United States
Environmental Protection
Agency
Office of Water (4203)
Washington, D.C. 20460
www.epa.gov/npdes
EPA 833-R-04-001
August 2004
v>EPA Report to Congress
Impacts and Control of CSOs and SSOs
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On the Cover
Large photo in background: Oklahoma City PVC sewer pipe stockpile. In response to problems from an aging sewer system
made up of more than 2,000 miles of pipe, Oklahoma City implementing a capital improvement planning program with the
goal of replacing sewer lines at the rate of 1 % per year. The City opted for replacing aging pipes with PVC pipes as a more
affordable, flexible and corrosion-resistant alternative. Photo courtesy of Julia Moore, Limno-Tech,lnc.
Top inset: Former Denny Way CSO outfall in Seattle, WA. The Denny Way outfall as shown was the largest volume CSO discharge
in the King County System.Through a joint effort of King Countyand the City of Seattle, the Denny Way/Lake Union CSO
Project was implemented to control over 600 million gallons of combined sewage from overflowing annually into Lake Union
and Elliott Bay. Under way since May 2000, construction is expected to be complete in 2005. Progress to date includes the
demolition of the pictured outfall, restoration of the shoreline, and revitalization of the surrounding public park. Photo courtesy
of King County.
Second inset: Monitoring team responding to sewer overflow. Photo provided by ADS.
Third inset: City of Richmond,VA Canal Walk.The City of Richmond incorporated downtown revitalization, historical
interpretation, and combined sewer overflow planning as part of a large-scale redevelopment of their downtown riverfront
area.The riverfront redevelopment was made possible, in part, by the environmental improvements achieved by the Richmond
CSO Control Program.The resulting Canal Walk extends for more than a mile along the Haxall and Kanawha Canals and includes
under canal routing of combined sewage while providing a pathway of access to revitalized businesses, museums and new
outdoor public vistas and arenas.Photo courtesy of City of Richmond.
Fourth inset: Orange County, CA. Orange County Health Care Agency's Environmental Health Ocean Water Protection Program
administers a beach water quality monitoring program to ensure public recreational waters meet bacteriological water quality
standards for full body contact recreational activities such as swimming, surfing and diving. Beach closure or advisory signs are
posted at Orange County beaches when high levels of bacteria are measured or when a sewage spill contamination of ocean or
bay waters occurs. Photo courtesy of OCHCA EH Ocean Water Protection Program.
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Table of Contents
Executive Summary—Report to Congress on the Impacts and Control of CSOs and SSOs ES-1
Chapter 1 —Introduction 1-1
1.1 What are CSOs and SSOs? 1-2
1.1.1 CSOs 1-2
1.1.2 SSOs 1-3
1.2 How is this Report Organized? 1-3
Chapter 2—Background 2-1
2.1 What is the History of Sewer Systems in the United States? 2-1
2.1.1 Combined Sewers and CSOs 2-3
2.1.2 Sanitary Sewers and SSOs 2-4
2.2 What is the History of Federal Water Pollution Control Programs? 2-6
2.2.1 Secondary Treatment 2-6
2.2.2 Construction Grants 2-7
2.2.3 Pretreatment 2-8
2.2.4 Wet Weather 2-8
2.2.5 Watershed-Based Permitting 2-9
2.3 What is the Federal Framework for CSO Control? 2-9
2.3.1 CSO Case Law 2-9
2.3.2 The National CSO Control Stategy and the MAG 2-10
2.3.3 The CSO Control Policy 2-10
2.4 What is the Federal Framework for SSO Control? 2-10
2.5 What is the Wet Weather Water Quality Act? 2-11
Chapter 3—Methodology 3-1
3.1 What Study Objectives and Approach Did EPA Use to Prepare this Report? 3-1
3.2 What Data Sources Were Used? 3-2
3.2.1 Federal Data Sources 3-2
3.2.2 NPDES Authority and Other State Program Data Sources 3-3
3.2.3 Community-Level Data Sources 3-3
3.2.4 Non-Governmental Organization Data Sources 3-3
3.3 What Data Were Collected? 3-4
3.3.1 Characterization of CSOs and SSOs 3-4
3.3.2 Extent of Environmental Impacts Caused by CSOs and SSOs 3-5
3.3.3 Extent of Human Health Impacts Caused by CSOs and SSOs 3-6
3.3.4 Evaluation of Technologies Used by Municipalities to Address Impacts Caused by CSOs and SSOs 3-8
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Report to Congress on the Impacts and Control ofCSOs and SSOs
3.3.5 Assessment of Resources Spent by Municipalities to Address Impacts Caused by CSOs and SSOs 3-8
3.4 How Were Stakeholders Involved in the Preparation of this Report? 3-9
3.5 What Data Considerations Are Important? 3-10
3.6 What Quality Control and Quality Assurance Protocols Were Used? 3-11
3.7 Summary 3-12
Chapter 4—Characterization of CSOs and SSOs 4-1
4.1 What Pollutants are in CSOs and SSOs? 4-2
4.1.1 Microbial Pathogens 4-3
4.1.2 BOD5 4-4
4.1.3 TSS 4-5
4.1.4 Toxics 4-6
4.1.5 Nutrients 4-7
4.1.6 Floatables 4-7
4.2 What Factors Influence the Concentrations of the Pollutants in CSOs and SSOs? 4-8
4.2.1 Factors Influencing Pollutant Concentrations in CSOs 4-8
4.2.2 Factors Influencing Pollutant Concentrations in SSOs 4-9
4.3 What Other Point and Nonpoint Sources Might Discharge These Pollutants to Waterbodies Receiving CSOs
and SSOs? 4-9
4.3.1 Wastewater Treatment Facilities 4-10
4.3.2 Decentralized Wastewater Treatment Systems 4-11
4.3.3 Industrial Point Sources 4-11
4.3.4 Urban Storm Water 4-12
4.3.5 Agriculture 4-12
4.3.6 Domestic Animals and Wildlife 4-12
4.3.7 Commercial and Recreational Vessels 4-13
4.4 What is the Universe of CSSs? 4-13
4.5 What are the Characteristics of CSOs? 4-16
4.5.1 Volume of CSOs 4-17
4.5.2 Frequency of CSOs 4-19
4.5.3 Location of CSOs 4-19
4.6 What is the Universe of SSSs? 4-20
4.7 What are the Characteristics of SSOs? 4-20
4.7.1 SSO Data Management System 4-20
4.7.2 Statistical Technique Used to Estimate Annual National SSO Frequency and Volume 4-23
4.7.3 Frequency of SSOs 4-24
4.7.4 Volume of SSOs 4-25
4.7.5 Location of SSOs 4-26
4.8 How Do the Volumes and Pollutant Loads from CSOs and SSOs Compare to Those from Other Municipal
Point Sources? . .. 4-29
Chapter 5—Environmental Impacts of CSOs and SSOs 5-1
5.1 What is EPAs Framework for Evaluating Environmental Impacts? 5-1
5.2 What Overall Water Quality Impacts Have Been Attributed to CSO and SSO Discharges in National Assessments? .. 5-3
5.2.1 NWQI 2000 Report 5-3
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5.2.2 Analysis of CSO Outfalls Discharging to Assessed or Impaired Waters 5-6
5.2.3 Modeled Assessment of SSO Impacts on Receiving Water Quality 5-8
5.3 What Impacts on Specific Designated Uses Have Been Attributed to CSO and SSO Discharges in National
Asssessments? 5-10
5.3.1 Recreation 5-10
5.3.2 Shellfish Harvesting 5-13
5.4 What Overall Water Quality Impacts Have Been Attributed to CSO and SSO Discharges in State and Local
Assessments? 5-15
5.4.1 Water Quality Assessment in New Hampshire 5-15
5.4.2 Water Quality Assessment of the Mahoning River Near Youngstown, Ohio 5-15
5.4.3 Water Quality Assessment in Indianapolis, Indiana 5-16
5.4.4 Water Quality Risk Assessment of CSO Discharges in King County, Washington 5-16
5.5 What Impacts on Specific Designated Uses Have Been Attributed to CSO and SSO Discharges in State and Local
Assessments? 5-17
5.5.1 Aquatic Life Support 5-18
5.5.2 Recreation 5-21
5.5.3 Shellfish Harvesting 5-25
5.6 What Factors Affect the Extent of Environmental Impacts Caused by CSOs and SSOs? 5-26
5.6.1 Timescale Considerations 5-28
5.6.2 Receiving Water Characteristics 5-28
Chapter 6—Human Health Impacts of CSOs and SSOs 6-1
6.1 What Pollutants in CSOs and SSOs Can Cause Human Health Impacts? 6-1
6.1.1 Microbial Pathogens 6-2
6.1.2 Toxics 6-4
6.1.3 Biologically Active Chemicals 6-6
6.2 What Exposure Pathways and Reported Human Health Impacts are Associated with CSOs and SSOs? 6-7
6.2.1 Recreational Water 6-7
6.2.2 Drinking Water Supplies 6-10
6.2.3 Fish and Shellfish 6-12
6.2.4 Direct Contact with Land-Based Discharges 6-13
6.2.5 Occupational Exposures 6-14
6.2.6 Secondary Transmission 6-15
6.3 Which Demographic Groups Face the Greatest Risk of Exposure to CSOs and SSOs? 6-16
6.3.1 Swimmers, Bathers, and Waders 6-16
6.3.2 Subsistence and Recreational Fishers 6-16
6.3.3 Wastewater Workers 6-17
6.4 Which Populations Face the Greatest Risk of Illness from Exposure to the Pollutants Present in CSOs and SSOs? .. 6-17
6.4.1 Pregnant Women 6-17
6.4.2 Children 6-17
6.4.3 Immunocompromised Groups 6-18
6.4.4 Elderly 6-18
6.5 How are Human Health Impacts from CSOs and SSOs Communicated, Mitigated, and Prevented? 6-18
6.5.1 Agencies and Organizations Responsible for Protecting Public Health 6-18
6.5.2 Activities to Protect Public Health from Impacts of CSOs and SSOs 6-22
6.6 What Factors Contribute to Information Gaps in Identifying and Tracking Human Health Impacts from CSOs
and SSOs? 6-24
6.6.1 Underreporting 6-24
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Report to Congress on the Impacts and Control ofCSOs and SSOs
6.6.2 Use of Indicator Bacteria 6-25
6.7 What New Assessment and Investigative Activities are Underway? 6-26
6.7.1 Investigative Activities 6-26
Chapter 7—Federal and State Efforts to Control CSOs and SSOs 7-1
7.1 What are States and EPA Regions Doing to Control CSOs? 7-1
7.1.1 Nine Minimum Controls 7-2
7.1.2 Long-Term Control Plans 7-2
7.2 What are States and EPA Regions Doing to Control SSOs? 7-3
7.2.1 Application of Standard Permit Conditions to SSOs 7-3
7.2.2 Electonic Tracking of SSOs 7-4
7.3 What Programs Have Been Developed to Control SSOs? 7-5
7.3.1 EPA Region 4's MOM Program 7-5
7.3.2 Oklahoma - Collection System Program 7-6
7.3.3 California - Record Keeping and Reporting of Events 7-7
7.3.4 North Carolina - Collection System Permitting 7-8
7.4 What Compliance and Enforcement Activities Have Been Undertaken? 7-8
7.4.1 National Municipal Policy on POTWs 7-9
7.4.2 Enforcement Management System 7-9
7.4.3 Compliance and Enforcement Strategy (2000) 7-9
7.4.4 Compliance Assistance 7-10
7.4.5 Summary of Enforcement Activities 7-11
Chapter 8—Technologies Used to Reduce the Impacts of CSOs and SSOs 8-1
8.1 What Technologies are Commonly Used to Control CSOs and SSOs? 8-2
8.1.1 Operation and Maintenance Practices 8-2
8.1.2 Collection System Controls 8-5
8.1.3 Storage Facilities 8-11
8.1.4 Treatment Technologies 8-13
8.1.5 Low-Impact Development Techniques 8-17
8.2 How Do CSO and SSO Controls Differ? 8-20
8.2.1 Common CSO Control Measures 8-20
8.2.2 Common SSO Control Measures 8-21
8.3 What Technology Combinations are Effective? 8-21
8.3.1 Inflow Reduction or Low-Impact Development Coupled with Structural Controls 8-22
8.3.2 Disinfection Coupled with Solids Removal 8-22
8.3.3 Sewer Rehabilitation Coupled with Sewer Cleaning 8-22
8.3.4 Real-Time Control Coupled with In-line or Off-line Storage Facilities 8-22
8.4 What New Technologies for CSO and SSO Control are Emerging? 8-23
8.4.1 Optimization of Sewer System Maintenance 8-23
8.4.2 Information Management 8-23
Chapter 9—Resources Spent Address the Impacts of CSOs and SSOs 9-1
9.1 What Federal Framework Exists for Evaluating Resources Spent on CSO and SSO Control? 9-1
9.2 What are the Past Investments in Wastewater Infrastructure? . .. 9-2
IV
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9.3 What Has Been Spent to Control CSOs? 9-5
9.4 What Has Been Spent to Control SSOs? 9-6
9.5 What Does it Cost to Maintain Sewer Systems? 9-7
9.6 What are the Projected Costs to Reduce CSOs? 9-8
9.7 What are the Projected Costs to Reduce SSOs? 9-9
9.8 What Funding Mechanisms are Available for CSO and SSO Control? 9-10
9.8.1 Self-financing 9-11
9.8.2 State and Federal Funding for CSO and SSO Control 9-12
Chapter 10—Conclusions and Future Challenges 10-1
Protecting Infrastructure 10-2
Implementing the Watershed Approach 10-3
Improving Monitoring and Information-Based Environmental Management 10-4
Building Strategic Partnerships 10-5
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Report to Congress on the Impacts and Control ofCSOs and SSOs
List of Figures
Figure ES.l—National Distribution of CSSs ES-5
Figure ES.2—National Distribution of SSSs ES-6
Figure ES.3—Sources of Pollution that Resulted in Swimming Beach Advisories and Closings ES-8
Figure 2.1—Typical Combined Sewer System 2-2
Figure 2.2—Typical Separate Sanitary and Storm Sewer Systems 2-2
Figure 2.3—National Distribution of Communities Served by CSSs 2-4
Figure 2.4—National Distribution of Communities Served by SSSs 2-5
Figure 4.1—Distribution of CSO Permits by Region and by State 4-14
Figure 4.2—Distribution of CSO Outfalls by Region and by State 4-15
Figure 4.3—Distribution POTW Facility Sizes Serving CSSs 4-17
Figure 4.4—Distribution of SSSs with Wastewater Treatment Facilities by Region and by State 4-21
Figure 4.5—Distribution of Satellite SSSs by Region and by State 4-22
Figure 4.6—States Providing Electronic Data on SSO Discharges 4-23
Figure 4.7—Total Number of SSO Events Reported by Individual Communities, January 1, 2001 - December 31, 2002 ... 4-25
Figure 4.8—Distribution of SSO Volume Reported Per Event 4-26
Figure 4.9—Most Common Reported Causes of SSO Events 4-27
Figure 4.10—Reported Causes of SSOs in Communities Reporting More than 100 SSO Events During a
Single Calendar Year 4-28
Figure 4.11—Reported Cause of Blockage Events 4-28
Figure 5.1—NWQI 2000 Summary of Assessed Waters by Waterbody Type 5-4
Figure 5.2—Sources of Pollution that Resulted in Beach Advisories and Closings 5-11
Figure 5.3—Sources of Water Quality Impairment in New Hampshire 5-16
Figure 5.4—Fish Species Found in the Chicago and Calumet River System, 1974 - 2001 5-22
Figure 5.5—Sources of Contamination Resulting in California Beach Closures in 2000 5-22
Figure 5.6—Beach Closures in California During 2000 Attributed to SSOs 5-23
Figure 5.7—Average Number Days per Year Coastal Municipalities in Connecticut Closed One or More Beaches 5-24
Figure 5.8— Lake Michigan Beach Closures, 1998- 2002 5-25
Figure 5.9— Movement of Bacteria Plume from SSO Discharge in Raritan Bay, New Jersey 5-27
Figure 6.1—Microbial Pathogens Linked to Outbreaks in Recreational Waters, 1985 - 2000 6-8
Figure 6.2—Microbial Pathogens Causing Outbreaks Linked to Drinking Water, 1985-2000 6-11
Figure 9.1—Annual Capital Expenditures on Wastewater Projects, 1970 - 2000 9-3
Figure 9.2—State and Local Expenditures on Wastewater O&M, 1970 - 2000 9-4
Figure 9.3—CWSRF Annual Expenditures for CSO Projects, 1988 - 2002 9-5
Figure 9.4—CWSRF Annual Expenditures for I/I and Sewer Replacement/Rehabilitation 9-6
Figure 9.5—Changes in Estimated Needs Between 1996 and 2000 CWNS 9-10
Figure 9.6—Revenue Sources for Municipal Wastewater Treatment 9-11
Figure 9.7—State and Local Expenditures Under the CWSRF Program for CSO Correction and SSO Capital Projects ... 9-12
VI
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Table of Contents
List of Tables
Table ES. 1—Comparison of Estimated Annual Discharge Volumes ES-7
Table 4.1—Fecal Coliform Concentrations in Municipal Discharges 4-3
Table 4.2—6005 Concentrations in Municipal Discharges 4-5
Table 4.3—TSS Concentrations in Municipal Discharges 4-5
Table 4.4—Cadmium and Copper Concentrations in Municipal Discharges 4-6
Table 4.5—Lead and Zinc Concentrations in Municipal Discharges 4-6
Table 4.6—Nutrient Concentrations in Municipal Discharges 4-6
Table 4.7—Volume Reduction Estimates Based on Implementation of CSO Control Policy 4-18
Table 4.8—SSO Event Volume by Cause 4-27
Table 4.9—Estimated Annual Municipal Point Source Discharges 4-29
Table 4.10—Estimated Annual 6005 Load from Municipal Point Sources 4-29
Table 4.11—Estimated Annual TSS Load from Municipal Point Sources 4-30
Table 4.12—Estimated Annual Fecal Coliform Load from Municipal Point Sources 4-30
Table 5.1—Pollutants of Concern in CSOs and SSOs Likely to Cause or Contribute to Impairment 5-3
Table 5.2—Pollutants and Stressors Most Often Associated with Impairment 5-6
Table 5.3—Leading Sources of Pollutants and Stressors Causing Water Quality Impairment 5-6
Table 5.4—Occurances of 305(b) Assessed Waters Within One Mile Downstream of a CSO Outfall 5-7
Table 5.5—Occurence of 303(d) Listed Waters Within One Mile Downstream of a CSO Outfall 5-8
Table 5.6—Estimated Perentage of Time SSOs Would Cause Water Quality Standard Violations 5-9
Table 5.7—NMDMP Marine Debris Survey Results from 1996 to 2002 5-12
Table 5.8—Pollution Sources Reported for Harvest Limitations on Classified Shellfish Growing Waters in the 1990 and 1995
National Shellfish Registers 5-14
Table 5.9—Harvest Limitations on Classified Shellfish Growing Areas Within Five Miles of a CSO Outfall 5-15
Table 5.10—Relative Contributions of Pollutant Sources to Water Quality Problems in Indianapolis, Indiana 5-17
Table 5.11—Fish Kills Reported in North Carolina: 1997 - 2002 5-18
Table 5.12—Fish Kills Caused by Sewage Spills in North Carolina: 1997 - 2001 5-20
Table 5.13—Summary of Unauthorized Wastewater Discharges in Orange County, California, that
Resulted in Beach Closures 5-25
Table 6.1—Common Pathogenic Bacteria Present in Sewage 6-3
Table 6.2—Common Enteric Viruses Present in Sewage 6-3
Table 6.3—Common Parasitic Protozoa Present in Sewage 6-4
Table 6.4—Concentration of Indicator Bacteria and Enteric Pathogens Shed by an Infected Individual 6-5
Table 6.5—Participation in Water-Based Recreation in U.S. during July 1999 and January 2001 6-7
Table 6.6—Estimated Number of Illnesses per Year Attributed to CSOs and SSOs 6-10
Table 6.7—Association of CSO Outfalls with Drinking Water Intakes 6-12
Table 6.8—Examples of Secondary Transmission from Waterborne and Non-Waterborne Disease Outbreaks 6-15
VII
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 7.1—Summary of Electronic SSO Data by State 7-4
Table 8.1—Summary of Operation and Maintenance Practices 8-3
Table 8.2—Summary of Collection System Controls 8-6
Table 8.3—Summary of Storage Facilities 8-12
Table 8.4—Summary of Treatment Technologies 8-15
Table 8.5—Summary of Low-Impact Development Techniques 8-18
Table 9.1—Annual Budget Expenditures in Sanitary Sewer Systems 9-7
Table 9.2—O&M Costs for Sewers . .. 9-8
VIM
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Table of Contents
List of Appendices
Appendix A Statutes, Policies, and Interpretative Memoranda
Appendix B Human Health Expert and Stakeholder Meeting Summaries
Appendix C Documentation of State and Municipal Interviews
Appendix D List of Active CSO Permits
Appendix E GPRACSO Model Documentation
Appendix F Analysis of CSO Receiving Waters Using the National Hydrography Dataset (NHD)
Appendix G National Estimate of SSO Frequency and Volume
Appendix H Estimation of SSO Impacts in Streams and Rivers
Appendix I Human Health Addendum
Appendix J Estimated Annual Illness Burden Resulting from Exposure to CSOs and SSOs at BEACH Survey Beaches
Appendix K Summary of Enforcement Actions
Appendix L Technology Descriptions
Appendix M Financial Information
IX
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List of Acronyms
AIDS- Acquired Immune Disorder
Syndrome
AMSA- Association of Metropolitan
Sewerage Agencies
AO- Administrative Order
APO- Administrative Penalty Orders
APWA- American Public Works
Association
ASCE- American Society of Civil
Engineers
BAT- Best Available Technology
Economically Achievable
BCT- Best Conventional Pollutant
Control Technology
BEACH Program- Beaches
Environmental Assessment and
Coastal Health Program
BMP- Best Management Practice
BOD5- Biochemical Oxygen Demand
(measured over 5 days)
CAFO- Concentrated Animal Feeding
Operation
CATAD- Computer Augmented
Treatment and Disposal
CBO- Congressional Budget Office
CCTV- Closed Circuit Television
CDC- Centers for Disease Control
and Prevention
CFR- Code of Federal Regulations
cfs- Cubic Feet per Second
CIPP- Cured-in-place Pipe
CMOM- Capacity, Management,
Operation, and Maintenance
CSO- Combined Sewer Overflow
CSS- Combined Sewer System
CTP- Central Treatment Plant
CWNS- Clean Watersheds Needs
Survey
CWSRF- Clean Water State Revolving
Fund
ECD- Enforcement and Compliance
Docket
ENR- Engineering News Record
EPA- Environmental Protection
Agency
FEE- Flow Equalization Basins
FAC- Federal Advisory Committee
FOG- Fats, Oils, and Grease
FR- Federal Register
FY- Fiscal Year
FWPCA- Federal Water Pollution
Control Act
GAO- Government Accounting Office
CIS- Geographic Information System
GPRA- Government Performance and
Results Act
HUD-Housing of Urban
Development
I/I- Infiltration & Inflow
ISSC- Interstate Shellfish Sanitation
Conference
LGEAN- Local Government
Environmental Assistance Network
LID- Low Impact Development
LOV- Letter of Violation
LTCP- Long-Term Control Plan
MAG- Office of Water Management
Advisory Group
MDE- Maryland Department of the
Environment
MDEQ- Michigan Department of
Environmental Quality
MG- Million Gallons
mgd- Million Gallons per Day
ml- Milliliter
ACR-1
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Report to Congress on the Impacts and Control of CSOs and SSOs
MMSD- Milwaukee Metropolitan
Sewarage District
MOM- Management, Operation, and
Maintenance
MPN- Most Probable Number
MWWSSB- Montegomery Water
Works and Sanitary Sewer Board
MS4- Municipal Separate Storm
Sewer System
NCDENR- North Carolina
Department of Environmental and
Natural Resources
NEEAR Water Study- National
Epidemiological and Environmental
Assessment of Recreational Water
Study
NIH- National Institutes of Health
NHD- National Hydrography Dataset
NJDEP- New Jersey Department of
Environmental Protection
NMC- Nine Minimum Controls
NMDSP- National Marine Debris
Survey Program
NMP-National Municipal Policy
NOAA-National Oceanic and
Atmospheric Administration
NPDES- National Pollutant Discharge
Elimination System
NRDC- Natural Resources Defense
Council
NURP- Nationwide Urban Runoff
Program
NWQI- National Water Quality
Inventory
WDR- Waste Discharge Requirements
WEF- Water Environment Federation
O&M- Operation and Maintenance
WERF- Water Environment Research
ODEQ- Oklahoma Department of Foundation
Environmental Quality
WISE- Watershed Initiative for a Safe
OMB- Office of Management and Environment
Budget
WWTP- Wastewater Treatment Plant
ORD- Office of Research and
Development
PCBs- Polychlorinated biphenyls
PCS- Permit Compliance System
PL.- Public Law
POTW- Publicly Owned Treatment
Works
REAP- Rural Economic Assistance
Program
RWQCB- Regional Water Quality
Control Board
SRF- State Revolving Fund
SSO- Sanitary Sewer Overflow
SSS- Sanitary Sewer System
TKN- Total Kjeldahl Nitrogen
TMDL- Total Maximum Daily Loads
TSS- Total Suspended Solids
USGS- United States Geological
Survey
UV- Ultraviolet
WATERS- Watershed Assessment,
Tracking, & Environmental Results
ACR-2
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Glossary
This glossary includes a collection of the terms used in this manual and an explanation of each term. To the
extent that definitions and explanations provided in this glossary differ from those in EPA regulations or other
official documents, they are intended for use in understanding this manual only.
A
Acute Toxicity- The ability of
a substance to cause severe
biological harm or death soon
after a single exposure or dose.
Also, any poisonous effect
resulting from a single short-term
exposure to a toxic substance.
B
Bacteria- Microscopic, unicellular
organisms, some of which
are pathogenic and can cause
infection and disease in animals
and humans. Most often, non-
pathogenic bacteria, such as fecal
coliform and enterococci, are used
to indicate the likely presence
of disease-causing, fecal-borne
microbial pathogens.
Best Available Technology
Economically Achievable (BAT)-
Technology-based standard
established by the Clean Water Act
as the most appropriate means
available on a national basis for
controlling the direct discharge
of toxic and nonconventional
pollutants to navigable waters.
Best Conventional Pollutant Control
Technology (BCT)- Technology-
based standard for the discharge
from existing industrial point
sources of conventional
pollutants including BOD, TSS,
fecal coliform, pH, oil and grease.
The BCT is established in light of
a two-part "cost reasonableness"
test, which compares the cost
for an industry to reduce its
pollutant discharge with the cost
to a POTW for similar levels of
reduction of a pollutant loading.
The second test examines the
cost-effectiveness of additional
industrial treatment beyond
BPT. EPA must find limits, which
are reasonable under both tests
before establishing them as BCT.
Biochemical Oxygen Demand
(BOD)- A measure of the
amount of oxygen consumed
by microorganisms from the
decomposition of organic
material in water over a specified
time period (usually 5 days,
indicated as BOD5). The
BOD5 value is used for many
applications, most commonly to
indicate the effects of sewage and
other organic wastes on dissolved
oxygen in water.
c
Chronic Toxicity- The capacity of
a substance to cause long-term
poisonous health effects in
humans, animals, fish, and other
organisms.
Clean Water Act- The Clean Water
Act is an act passed by the
U.S. Congress to control water
pollution. It was formerly
referred to as the Federal Water
Pollution Control Act of 1972 or
Federal Water Pollution Control
Act Amendments of 1972 (PL.
92-500), 33 U.S.C. 1251 et. seq.,
as amended by: PL. 96-483; PL.
97-117; PL. 95-217, 97-117,
97-440, and 100-04.
GL-1
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Combined Sewer Overflow (CSO)- A
discharge of untreated wastewater
from a combined sewer system at
a point prior to the headworks of
a publicly owned treatment works
(POTW).
Combined Sewer System (CSS)- A
wastewater collection system
owned by a municipality (as
defined by Section 502(4) of the
Clean Water Act) that conveys
domestic, commercial and
industrial wastewater and storm
water runoff through a single pipe
system to a POTW.
Concentrated Animal Feeding
Operation (CAFO)- New
and existing animal feeding
operations of a sufficient size
that are required to develop
and implement a nutrient
management plan as a condition
of a NPDES permit (defined at 40
CFR 122.23).
Construction Grants Program-
Federal assistance program
authorized under Section 201
of the Clean Water Act intended
to assist with the development
and implementation of waste
treatment management plans and
practices that will achieve the
goals of the Act.
Conventional Pollutants- As
defined by the Clean Water Act,
conventional pollutants include:
BOD, TSS, fecal coliform, pH, and
oil and grease.
D
Dissolved Oxygen (DO)- The
oxygen freely available in water,
vital to fish and other aquatic
life and for the prevention of
odors. DO levels are considered
a most important indicator of a
water body's ability to support
desirable aquatic life. Secondary
and advanced waste treatment
are generally designed to ensure
adequate DO in waste-receiving
waters.
Diurnal- Relating to or occurring
in a 24-hour period, or daily. A
pattern that repeats itself over a
daily cycle.
Dry Weather CSO- An unauthorized
discharge from a combined sewer
system that occurs during dry
weather conditions.
Dry Weather SSO- A sanitary sewer
overflow that occurs during dry
weather conditions, most often as
a result of blockages, line breaks,
or mechanical/power failures in
the collection system.
E
Effluent Limits- Restrictions
established by a state or EPA
on quantities, rates, and
concentrations in municipal or
industrial wastewater discharges.
Environmental Impact- Any change
to the environment, whether
adverse or beneficial, wholly
or partially resulting from an
organization's activities, products
or services.
Eutrophic Condition- The presence
of excess nutrients in a receiving
water body. During the later
stages of eutrophication the water
body can become choked by
abundant plant life due to higher
levels of nutritive compounds
such as nitrogen and phosphorus.
F
Federal Advisory Committee- Any
committee, board, commission,
council, conference, panel, task
force, or other similar group,
or any subcommittee or other
sub-group thereof (hereafter
in this paragraph referred
to as "committee"), which
in— (A) established by statute
or organization plan, or (B)
established or utilized by the
President; or (C) established or
utilized by one or more agencies;
in the interest of obtaining
advise and recommendations
for the President or one or more
agencies or offices of the Federal
Government, except that such
term excludes (i) any committee
that is composed wholly of full-
time, or permanent part-time,
officers or employees of the
Federal Government, and (ii) any
committee that is created by the
National Academy of Sciences of
the National Academy of Public
Administration.
First Flush- The occurrence of higher
concentrations of pollutants in
GL-2
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Glossary
storm water or CSO discharges at
the beginning of a storm.
Floatables and Trash- Visible buoyant
or semi-buoyant solids including
organic matter, personal hygiene
items, plastics, styrofoam, paper,
rubber, glass and wood.
H
Headworks of a Wastewater Treatment
Plant- The initial structures,
devices and processes provided
at a wastewater treatment plant
including screening, pumping,
measuring, and grit removal
facilities.
Human Health Impacts- Damage
to the health of an individual or
individuals due to a given exposure
or a series of exposures.
Indicator Bacteria- Bacteria that
are common in human waste.
Indicator bacteria are not harmful
in themselves but their presence is
used to indicate the likely presence
of disease-causing, fecal-borne
microbial pathogens that are more
difficult to detect.
Infiltration- Storm water and
groundwater that enter a sewer
system through such means
as defective pipes, pipe joints,
connections, or manholes.
(Infiltration does not include
inflow).
Infiltration/Inflow (I/I)- The total
quantity of water from both
infiltration and inflow.
Inflow- Water, other than wastewater,
that enters a sewer system from
sources such as roof leaders,
cellar drains, yard drains, area
drains, foundation drains, drains
from springs and swampy areas,
manhole covers, cross connections
between storm drains and sanitary
sewers, catch basins, cooling
towers, storm waters, surface
runoff, street wash waters, or
other drainage. (Inflow does not
include infiltration).
L
Long-Term Control Plan (LTCP)-
Water quality-based CSO control
plan that is ultimately intended
to result in compliance with
the Clan Water Act. Long-term
control plans should consider the
site-specific nature of CSOs and
evaluate the cost effectiveness of a
range of controls.
M
Major Facility- Classification for
wastewater treatment plants
that are designed to discharge
more than 1 mgd. Some facilities
with smaller design flows are
classified as major facilities
when the NPDES authority
deems it necessary for a specific
NPDES permit to have a stronger
regulatory focus.
Microbial Pathogens- Minute life
forms including bacteria, viruses
and parasites that can cause disease
in aquatic biota and illness or even
death in humans.
Million Gallons per Day (mgd)- A
unit of flow commonly used for
wastewater discharges. One mgd is
equivalent to a flow rate of 1.547
cubic feet per second over a 24-
hour period.
Minor Facility- A classification for
wastewater treatment plants that
are designed to discharge less than
1 mgd.
N
National Pollutant Discharge
Elimination System (NPDES)- The
national program for issuing,
modifying, revoking and reissuing,
terminating, monitoring and
enforcing permits, and imposing
and enforcing pretreatment
requirements, under Sections 307,
318, 402, and 405 of the Clean
Water Act.
Nine Minimum Controls (NMC)-
Technology-based CSO controls
that do not require significant
engineering studies or major
construction.
Nutrient- Any substance assimilated by
living things that promotes growth.
The term is generally applied
to nitrogen and phosphorus in
wastewater, but is also applied to
other essential and trace elements.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
o
Oxygen Depleting Substances-
Materials including human waste
and other organic matter that
cause a loss of oxygen in water and
wastewater, typically measured in
treatment, recycling, and
reclamation of municipal sewage
or industrial wastes of a liquid
nature. It also includes sewers,
pipes, and other conveyances only
if they convey wastewater to a
POTW treatment plant [40 CFR
§403.3].
terms of BOD c
P
Parasites- Animals or plants that live
in and obtain nutrients from a
host organism of another species.
Pathogenic- Capable of causing
disease.
Point Source- Any discernible,
confined, and discrete conveyance,
including but not limited
to any pipe, ditch, channel,
tunnel, conduit, well, discrete
fixture, container, rolling stock,
concentrated animal feeding
operation, landfill leachate
collection system, vessel, or
other floating craft from
which pollutants are or may be
discharged.
Primary Treatment- First steps in
wastewater treatment wherein
screens and sedimentation tanks
are used to remove most materials
that float or will settle.
Publicly Owned Treatment Works
(POTW)- A treatment works,
as defined by Section 212 of the
Clean Water Act that is owned
by a state or municipality. This
definition includes any devices
and systems used in the storage,
Q
Sanitary Sewer Overflow (SSO)- An
untreated or partially treated
sewage release from a sanitary
sewer system.
Sanitary Sewer System (SSS)- A
municipal wastewater collection
system that conveys domestic,
commercial and industrial
wastewater, and limited amounts
of infiltrated ground water and
storm water, to a POTW. Areas
served by sanitary sewer systems
often have a municipal separate
storm sewer system to collect and
convey runoff from rainfall and
snowmelt.
Satellite Sewer Systems- Combined
or separate sewer systems that
convey flow to a publicly owned
treatment works owned and
operated by a separate entity.
Secondary Treatment-
Technology-based requirements
for direct discharging
municipal sewage treatment
facilities. Standard is based
on a combination of physical
and biological processes for
the treatment of pollutants in
municipal sewage. Standards
are expressed as a minimum
level of effluent quality in terms
of: BOD^, suspended solids,
and pH (except as provided
for special considerations and
treatment equivalent to secondary
treatment).
State Revolving Fund Program- A
federal program created by the
Clean Water Act Amendments in
1987 that offers low interest loans
for wastewater treatment projects.
T
Technology-Based Effluent Limit-
Effluent limitations applicable to
direct and indirect sources, which
are developed on a category-by-
category basis using statutory
factors, not including water quality
effects.
Total Suspended Solids (TSS)- A
measure of the filterable solids
present in a sample of water or
wastewater (as determined by the
method specified in 40 CFR Part
136).
Toxics- Materials contaminating the
environment that cause death,
disease, and/or birth defects in
organisms that ingest or absorb
them. The quantities and length of
exposure necessary to cause these
effects can vary widely.
w
Water Quality Standard- A law
or regulation that consists of
the beneficial use or uses of a
waterbody, the numeric and
GL-4
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Glossary
narrative water quality criteria that
are necessary to protect the use or
uses of that particular waterbody,
and an antidegradation statement.
Water Quality-Based Effluent
Limitations- Effluent limitations
applied to dischargers when
technology-based limitations
insufficient to result in the
attainment of water quality
standards. Usually applied to
discharges into small streams.
Waters of the United States- All waters
that are currently used, were used
in the past, or may be susceptible
to use in interstate or foreign
commerce, including all waters
subject to the ebb and flow of the
tide. Waters of the United States
include but are not limited to all
interstate waters and intrastate
lakes, rivers, streams (including
intermittent streams), mudflats,
sand flats, wetlands, sloughs,
prairie potholes, wet meadows,
play lakes, or natural ponds. [See
40 CFR §122.2 for the complete
definition.]
Watershed Approach- An initiative
that promotes integrated
solutions to address surface
water, groundwater, and habitat
concerns on a watershed basis.
It is a decision-making process
that reflects a common strategy
for information collection
and analysis and a common
understanding of the roles,
priorities and responsibilities of all
stakeholders within a watershed.
Wet Weather Event- A discharge
from a combined or sanitary
sewer system that occurs in direct
response to rainfall or snowmelt.
Wet Weather SSO- A sanitary sewer
overflow that results from the
introduction of excessive inflow
and infiltration into a sanitary
sewer system, such that the total
flow exceeds conveyance capacity.
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Executive Summary
Report to Congress on the Impacts
and Control of CSOs and SSOs
The U.S. Environmental
Protection Agency (EPA or
"the Agency") is transmitting
this Report to Congress on the extent
of human health and environmental
impacts caused by municipal
combined sewer overflows (CSOs)
and sanitary sewer overflows (SSOs),
including the location of discharges
causing such impacts, the volume of
pollutants discharged, the constituents
discharged, the resources spent
by municipalities to address these
impacts, and the technologies used
by municipalities to address these
impacts.
Overview and Background
Why is EPA Preparing this Report?
In the Consolidated Appropriations
Act for Fiscal Year 2001, PL. 106-
554 (or "2000 amendments to the
Clean Water Act"), Congress requested
two reports and the development of
a technology clearinghouse. The first
report was transmitted to Congress in
December 2001 as Report to Congress-
Implementation and Enforcement
of the Combined Sewer Overflow
Control Policy (EPA 200la). This
second Report to Congress fulfills the
requirement that:
Not later than 3 years after
the date of enactment of this
Act, the Administrator of the
Environmental Protection Agency
shall transmit to Congress a report
summarizing-
(A) the extent of human health
and environmental impacts
caused by municipal combined
sewer overflows and sanitary
sewer overflows, including the
location of discharges causing such
impacts, the volume of pollutants
discharged, and the constituents
discharged;
(B) the resources spent by
municipalities to address these
impacts; and
(C) an evaluation of the
technologies used by municipalities
to address these impacts.
Further, the technology information
compiled for this Report to
Congress will serve as a key element
in developing the technology
SSOs include untreated discharges from SSSs
that reach waters of the United States, as
well as overflows out of manholes and onto
city streets, sidewalks, and other terrestrial
locations.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
clearinghouse requested by P.L. 106-
554.
What are CSOs and Why are They a
Problem?
Two types of public sewer systems
predominate in the United States:
combined sewer systems (CSSs) and
sanitary sewer systems (SSSs). CSSs
were among the earliest sewer systems
constructed in the United States and
were built until the first part of the
20th century. As defined in the 1994
CSO Control Policy (EPA 1994a), a
CSS is:
A -waste-water collection system
owned by a state of'municipality
(as defined by Section 502(4)
of the Clean Water Act) that
conveys domestic, commercial, and
industrial waste-waters and storm
water runoff through a single
pipe system to a publicly-owned
treatment works (POTW).
During wet weather events (e.g.,
rainfall or snowmelt), the combined
volume of wastewater and storm water
runoff entering CSSs often exceeds
conveyance capacity. Most CSSs are
designed to discharge flows that
exceed conveyance capacity directly to
surface waters, such as rivers, streams,
estuaries, and coastal waters. Such
events are called CSOs.
A CSO is defined as:
The discharge from a CSS at
a point prior to the POTW
treatment plant.
Some CSO outfalls discharge
infrequently, while others discharge
every time it rains. Overflow
frequency and duration varies from
system to system and from outfall to
outfall within a single CSS. Because
CSOs contain untreated wastewater
and storm water, they contribute
microbial pathogens and other
pollutants to surface waters. CSOs
can impact the environment and
human health. Specifically, CSOs
can cause or contribute to water
quality impairments, beach closures,
shellfish bed closures, contamination
of drinking water supplies, and other
environmental and human health
problems.
What are SSOs and Why are They a
Problem?
Since the first part of the 20* century,
municipalities in the United States
have generally constructed SSSs.
For the purposes of this Report to
Congress, an SSS is:
A municipal wastewater collection
system that conveys domestic,
commercial, and industrial
wastewater, and limited amounts
of infiltrated ground-water and
storm -water, to a POTW.
SSSs are not designed to collect large
amounts of storm water runoff from
precipitation events. Areas served by
SSSs often have a municipal separate
storm sewer system (MS4) to collect
and convey runoff from rainfall and
snowmelt.
Untreated or partially treated
discharges from SSSs are commonly
referred to as SSOs. SSOs have a
variety of causes including blockages,
line breaks, sewer defects that allow
excess storm water and groundwater
to overload the system, lapses in sewer
system operation and maintenance,
inadequate sewer design and
ES-2
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Executive Summary
construction, power failures, and
vandalism. An SSO is defined as:
An untreated or partially treated
sewage release from a SSS.
The discussion of SSOs in this
report, including national estimates
of SSO volume and frequency, does
not account for discharges from
points after the headworks of the
treatment plant, regardless of the
level of treatment, or backups into
buildings caused by problems in the
publicly-owned portion of the SSS.
EPA found that backups into buildings
are not widely tracked by permitting
authorities.
Generally speaking, SSOs can occur
at any point in an SSS, during dry
weather or wet weather. SSOs include
overflows that reach waters of the
United States. SSOs also include
overflows out of manholes and onto
city streets, sidewalks, and other
terrestrial locations. A limited number
of municipalities have SSOs that
discharge from fixed points within
their sewer system. SSSs can back
up into buildings, including private
residences. When sewage backups are
caused by problems in the publicly-
owned portion of an SSS, they are
considered SSOs.
SSOs can range in volume from
one gallon to millions of gallons.
The microbial pathogens and other
pollutants present in SSOs can
cause or contribute to water quality
impairments, beach closures, shellfish
bed closures, contamination of
drinking water supplies, and other
environmental and human health
problems.
What Statutory and Regulatory
Framework Applies to CSOs and
SSOs?
With extensive and documented
stakeholder support, EPA issued
its final CSO Control Policy on
April 19, 1994 (59 FR 18688). The
CSO Control Policy "represents a
comprehensive national strategy to
ensure that municipalities, permitting
authorities, water quality standards
authorities, and the public engage in a
comprehensive and coordinated effort
to achieve cost-effective CSO controls
that ultimately meet appropriate
health and environmental objectives."
When the CSO Control Policy was
released, many stakeholders, key
members of Congress, and EPA
advocated for it to be endorsed in
the Clean Water Act to ensure its full
implementation. In the Consolidated
Appropriations Act for Fiscal Year
2001, PL. 106-554, Congress stated
that:
...each permit, order, or decree
issued pursuant to this Act after
the date of enactment of this
subsection for a discharge from a
municipal combined storm and
sanitary sewer shall conform to the
CSO Control Policy signed by the
Administrator on April 11, 1994.
SSOs that reach waters of the United
States are point source discharges,
and, like other point source discharges
from municipal SSSs, are prohibited
unless authorized by an National
Pollutant Discharge Elimination
System (NPDES) permit. Moreover,
SSOs, including those that do not
reach waters of the United States, may
be indicative of improper operation
and maintenance of the sewer system,
CSO outfalls were constructed in a wide
variety of shapes and sizes, including the
large box culvert shown here. In general, CSO
outfalls discharge directly to receiving waters.
Photo: City of Wilmington, DE
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Report to Congress on the Impacts and Control ofCSOs and SSOs
and thus may violate NPDES permit
conditions.
What Methodology Did EPA Use
for this Report to Congress?
The basic study approach for this
report was to divide the congressional
request into a series of discrete study
questions, then to identify and collect
existing data appropriate to each study
question. This effort entailed:
• Reviewing existing data collected
by EPA and other federal agencies,
state and local governments, and
non-governmental organizations;
• Searching the existing literature
for environmental and human
health impacts attributable to
CSOs and SSOs, as well as the cost
and technologies used to control
CSOs and SSOs;
• Organizing forums to work
with EPA and external experts
and stakeholders on the specific
questions addressed in this report;
• Updating, verifying, and
establishing latitude and longitude
coordinates for the inventory of
CSO outfalls developed as part
of EPAs 2001 Report to Congress-
Implementation and Enforcement
of the Combined Sewer Overflow
Control Policy;
• Collecting SSO event information
from those states that compile
data on the volume, frequency,
and cause of SSO events in
electronic data management
systems;
• Developing national estimates
of the volume and frequency of
CSOs and SSOs; and
• Developing simple models to
estimate environmental and
human health impacts where there
was an absence of direct cause-
and-effect data.
EPA emphasized the collection,
compilation, and analysis of existing
data for this report. This effort allowed
the Agency to expand its knowledge
about CSOs and SSOs, and to identify
gaps in the existing data and in
current systems that provide such data.
This Report to Congress recognizes
that EPA should and will continue
to investigate the environmental and
human health challenges posed by wet
weather.
Response to Congress
EPAs response to the
congressional request set forth
in PL. 106-554 is presented
below, organized into five themes
addressing both CSOs and SSOs:
• Characterization
• Environmental impacts
• Human health impacts
• Control technologies
• Resources spent
What are the Location, Volume of
Pollutants, and Constituents of
CSOs and SSOs?
Currently, 828 NPDES permits
authorize discharges from 9,348 CSO
outfalls in 32 states (including the
District of Columbia). As shown in
Figure ES.l, most CSSs are located in
the Northeast and Great Lakes regions.
ES-4
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Executive Summary
The estimated volume of CSO
discharged nationwide is 850 billion
gallons per year. The number of
CSSs and CSO permits has decreased
slightly since publication of EPA's 2001
Report to Congress-Implementation
and Enforcement of the Combined
Sewer Overflow Control Policy. Further,
the percentage of CSO long-term
control plans (LTCPs) that have been
submitted to permitting authorities
has increased from 34 to 59 percent.
This represents progress in controlling
CSOs in the United States.
As shown in Figure ES.2, SSSs are
located across the country. EPA's
2000 Clean Watersheds Needs Survey
(CWNS) Report to Congress reported
15,582 municipal SSSs with wastewater
treatment facilities; an additional
4,846 satellite SSSs collect and
transport wastewater flows to regional
wastewater treatment facilities. SSOs
have the potential to occur in any of
these SSSs.
EPA estimates that between 23,000
and 75,000 SSO events occur per year
in the United States, discharging a
total volume of three to 10 billion
gallons per year. This estimate does
not account for discharges occurring
after the headworks of the treatment
plant or backups into buildings caused
by problems in the publicly-owned
portion of an SSS. The majority
of SSO events are caused by sewer
blockages that can occur at any time.
The majority of SSO volume appears
to be related to events caused by wet
weather and excessive inflow and
infiltration.
Figure ES.1
National Distribution
of CSSs
The majority of CSO permits are
held by communities located in
the Northeast and Great Lakes
regions.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure ES.2
National Distribution
of SSSs
SSSs are widely distributed
across the United States, serving
municipalities in all 50 states.
Approximately 75 percent of SSSs
are shown, where location data
(latitude/longitude) were available
from EPA's Permits Compliance
System.
A comparison of the estimated annual
CSO and SSO discharge volume with
treated wastewater is presented in
Table ES.l.
CSOs and SSOs contain untreated
wastewater, and therefore the pollutant
concentration depends on the service
population, the characteristics of the
sewer system, weather conditions, any
treatment provided, and other factors.
The principal pollutants present in
CSOs and SSOs are:
• Microbial pathogens
• Oxygen depleting substances
• Total suspended solids (TSS)
• Toxics
• Nutrients
• Floatables and trash
Pollutant concentrations in CSOs
and SSOs vary substantially, not only
from community to community and
event to event, but also within a given
event. CSOs and SSOs contribute
pollutant loadings to waterbodies
where discharges occur. It is important
to note that waterbodies also receive
pollutants of the types found in CSOs
and SSOs from other sources such as
storm water runoff.
ES-6
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Executive Summary
Treated wastewater3
CSOb
SSOC
Annual Discharge Volume
(billion gallons)
11,425
850
3-10
Table ES.1
a EPA 2000a
b GPRACSO model, Section 4.5.1 of this report
c Section 4.7.4 of this report
What is the Extent of
Environmental Impacts Caused by
CSOs and SSOs?
Pollutant concentrations in CSOs
and SSOs may be sufficient to cause a
violation of water quality standards,
precluding the attainment of one or
more of the designated uses (e.g.,
swimming, boating, fishing) for the
waterbody.
CSOs and wet weather SSOs discharge
simultaneously with storm water
runoff and other nonpoint sources of
pollution. EPA recognizes that this can
make it difficult to identify and assign
specific cause-and-effect relationships
between CSOs, SSOs, and observed
water quality problems. In addition,
EPA found that the identification
and quantification of environmental
impacts caused by CSOs and SSOs
at the national level is difficult
because there is no comprehensive
national data system for tracking the
occurrence and impacts of CSOs and
SSOs.
Nevertheless, CSOs and SSOs can
by themselves affect the attainment
of designated uses and cause water
quality standards violations. Average
bacteria concentrations in CSOs and
SSOs may be several thousand times
greater than water quality standard
criteria, and waterbodies that receive
CSO and SSO discharges may lack
sufficient dilution or assimilative
capacity. Based on modeling analysis
conducted by EPA and summarized in
Table 5.6 of this report, water quality
standards are projected to be violated
frequently, even in the absence
of other sources of fecal coliform
pollution, where discharges from SSO
events include more concentrated
wastewater (e.g., SSOs with limited
I/I) or when SSOs discharge to smaller
receiving waters such as a stream or
small tributary.
As shown in Figure ES.3, CSOs were
responsible for 1 percent of reported
advisories and closings, and 2 percent
of advisories and closings that had
a known cause during the 2002
swimming season. SSOs were reported
to be responsible for 6 percent of
reported advisories and closings, and
12 percent of advisories and closings
having a known cause. Studies also
identify CSOs and SSOs as a cause
of shellfish harvesting prohibitions
and restrictions in classified shellfish
growing areas.
The environmental impacts of CSOs
and SSOs are most apparent at the
local level, and as the result of large
or recurrent discharges. Examples of
localized impacts due to CSOs and
SSOs include:
Estimated Annual
Discharge Volumes
On an annual basis,the volume
of CSO and SSO discharged is a
proportionally small amount
compared to the total flow
processed at municipal treatment
facilities.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure ES.3
Sources of Pollution
Resulting in Swimming
Beach Advisories and
Closings (EPA 2003a)
EPA's Beaches Environmental
Assessment and Coastal (BEACH)
Program conducts an annual survey
of the nation's swimming beaches.
During the 2002 swimming season,
CSOs and SSOs (including sewer
line blockages and breaks) were
responsible for 1 and 6 percent of
reported closings and advisories,
respectively.
o
i/i
o
cso
POTW
Boat discharge
Septic system
SSO
Other
Wildlife
Storm water runoff
Unknown
• The City of Indianapolis assessed
receiving waters in the city and
ranked CSOs high in importance
relative to other sources of
pollution.
• The State of North Carolina has
documented fish kills attributed to
SSOs since 1997.
• The State of New Jersey closed
over 30,000 acres of classified
shellfish growing areas in the
Raritan Bay area due to a large
SSO in 2003.
What is the Extent of Human
Health Impacts Caused by CSOs
and SSOs?
Microbial pathogens and toxics can
be present in CSOs and SSOs at levels
that pose risks to human health.
Human health impacts occur when
people become ill due to contact with
water or ingestion of water or shellfish
that have been contaminated by CSO
or SSO discharges. In addition, CSSs
and SSSs can back up into buildings,
including private residences. These
discharges provide a direct pathway
for human contact with untreated
wastewater. Exposure to land-based
SSOs typically occurs through the
skin via direct contact. The resulting
diseases are often similar to those
associated with exposure through
drinking water and swimming (e.g.,
gastroenteritis), but may also include
illness caused by inhaling microbial
pathogens.
Although it is clear that CSOs
and SSOs contain disease-causing
pathogens and other pollutants, EPA
has limited information on actual
human health impacts occurring as a
result of CSO and SSO events. Further,
CSOs and wet weather SSOs also tend
to occur at times (e.g., storm events)
when exposure potential may be lower.
Identification and quantification
of human health impacts caused
by CSOs and SSOs at the national
ES-8
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Executive Summary
level is difficult due to a number of
factors, including under-reporting and
incomplete tracking of waterborne
illness, contributions of pollutants
from other sources, and the lack of a
comprehensive national data system
for tracking the occurrence and
impacts of CSOs and SSOs. As an
alternative to direct data on human
health impacts, EPA modeled the
annual number of gastroenteritis
cases potentially occurring as a result
of exposure to water contaminated
by CSOs and SSOs at BEACH survey
beaches. As shown in Table 6.6,
EPA found that CSOs and SSOs are
estimated to cause between 3,448 and
5,576 illnesses annually at the subset
of recreational areas included in the
analysis.
What Technologies Have
Municipalities Used to Reduce the
Impacts of CSOs and SSOs?
Municipalities have many options in
selecting technologies to reduce the
impacts of CSOs and SSOs. These
technologies range from large-scale
structural projects (e.g., wet weather
storage facilities) to operation and
maintenance practices (e.g., sewer
cleaning). Technology selection is
determined by characteristics of the
sewer system, problems identified in
the sewer system, performance goals
established for the sewer system,
resources available, and other site-
specific considerations.
Municipalities employ a wide variety
of technologies and operating
practices to maintain existing
infrastructure, minimize the
introduction of unnecessary waste
and flow into the sewer system,
increase capture and treatment of
wet weather flow reaching the sewer
system, and minimize the impact of
any subsequent discharges on the
environment and human health. For
this Report to Congress, technologies
used to address CSOs and SSOs
have been grouped into five broad
categories:
• Operation and maintenance
practices
• Collection system controls
• Storage facilities
• Treatment technologies
• Low-impact development
techniques
EPA, states, and municipalities have
made progress in developing tools and
strategies for reducing the frequency
and volume of CSOs and SSOs.
Much remains to be done, however,
to fully realize the objectives of the
Clean Water Act and the CSO Control
Policy. Municipalities have suggested
that limited resources prevent them
from acquiring and implementing
technologies as quickly as they and
regulatory agencies would prefer.
What Resources Have
Municipalities Spent to Address
the Impacts of CSOs and SSOs?
Municipal resources used to address
CSOs and SSOs are documented in
different ways. EPAs estimates of
municipal CSO expenditures rely
on requests for Clean Water State
Revolving Loan Fund (CWSRF)
loans and on documents submitted
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Report to Congress on the Impacts and Control ofCSOs and SSOs
to EPA's CWNS, which include CSO
LTCPs and other facility planning
documents. In addition, EPA uses a
cost curve methodology to estimate
costs for communities with CSSs
that do not submit documentation.
In communities served by SSSs, SSO
control expenditures are generally
a combination of general operation
and maintenance (O&M) and
capital expenditures. In total, EPA
documented expenditures of more
than $6 billion on CSO control
(through 2002) and at least $4 billion
on SSO control (1998-2002). EPA's
2000 CWNS estimated that at least an
additional $50.6 billion is required to
capture no less than 85 percent of the
CSO by volume, and an additional
$88.8 billion is required to control
SSOs over the next 20 years (EPA
2003b).
What Actions Should be Taken to
Reduce the Impacts of CSOs and
SSOs?
In its preparation of this report, EPA
found that:
Maintaining and improving the
integrity of the nation's wastewater
infrastructure will protect the high
level of environmental quality and
public health enjoyed in the United
States. Proper O&M of the nation's
sewers is integral to ensuring that
wastewater is collected, transported,
and treated at POTWs; and to
reducing the volume and frequency
of CSO and SSO discharges. Many
existing structural and non-structural
technologies are well suited for
CSO and SSO control. Emerging
technologies and innovative practices
hold promise for even greater
reductions in pollution. Municipal
owners and operators of sewer systems
and wastewater treatment facilities
need to manage their assets effectively
and implement new controls, where
necessary, as this infrastructure
continues to age.
The impacts of CSOs and SSOs are a
concern at the local watershed level.
CSOs and SSOs are two among many
sources of pollutants that contribute
to urban water quality problems.
The watershed approach is central
to water quality assessments and the
identification of control strategies
must include all sources of pollution
affecting water quality. The presence
of sewer systems in most developed
watersheds nationwide underscores
the importance of considering
potential SSOs impacts on water
quality. Similarly, the presence of
CSOs in 32 states places them in
many watersheds across the country.
EPA, states, and municipalities should
strive toward better integration of
wet weather programs with other
NPDES, compliance assistance,
and enforcement activities. Better
integration of programs and activities
at the watershed level will provide
economies of scale with respect to
monitoring and reporting, protecting
water quality, and reducing the
impacts of CSOs and SSOs.
Improved monitoring and reporting
programs would provide better
data for decision-makers on CSO
and SSO control. Better tracking
of environmental impacts and the
incidence of waterborne disease would
increase national understanding of
the environmental and human health
impacts associated with CSOs, SSOs,
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Executive Summary
and other sources of pollution. Use
of standardized reporting formats
for information on the occurrence
and control of CSOs and SSOs would
enable EPA, states, and others to track
pollutant loads and the performance
of controls. Recent EPA efforts such
as WATERS (Watershed Assessment,
Tracking, and Environmental
ResultS) work to unite national
water quality information that was
previously available only from several
independent and unconnected
databases. EPA will continue to work
to improve the information available.
The success that the nation has
achieved in improving water quality
since passage of the Clean Water Act is
due to the collective efforts of federal
and state agencies, municipalities,
industry, non-governmental
organizations, and citizens. Continued
cooperation among these groups
is essential to meet the challenges
to clean water that lie ahead. As
described in this Report to Congress,
numerous pollutant sources threaten
the environment and human health,
but establishing direct cause-and-
effect relationships is often difficult.
The information necessary to manage
water quality problems comes from
many sources. EPA recognizes the
value of working with stakeholders
and has pursued a strategy of extensive
stakeholder participation in its policy-
making on CSO and SSO issues.
Likewise, as communities continue
to implement CSO and SSO controls,
further cooperation with municipal,
industry, and environmental
organizations is essential to ensure
successful development and
implementation of environmental
programs.
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Chapter 1
Introduction
This Report to Congress presents
U.S. Environmental Protection
Agency's (EPA or "the Agency")
most recent and comprehensive
characterization of combined sewer
overflows (CSOs) and sanitary sewer
overflows (SSOs), including the extent
of human health and environmental
impacts caused by CSOs and SSOs,
the resources spent by municipalities
to address these impacts, and the
technologies used by municipalities to
address these impacts. This report has
been prepared in direct response to a
congressional mandate established in
December 2000 in the Consolidated
Appropriations Act for Fiscal Year
2001, PL. 106-554, which requires
that:
Not later than 3 years after
the date of enactment of this
Act, the Administrator of the
Environmental Protection Agency
shall transmit to Congress a report
summarizing—
(A) the extent of human health
and environmental impacts
caused by municipal combined
sewer overflows and sanitary
sewer overflows, including the
location of discharges causing such
impacts, the volume of pollutants
discharged, and the constituents
discharged;
(B) the resources spent by
municipalities to address these
impacts; and
(C) an evaluation of the
technologies used by municipalities
to address these impacts.
EPA prepared this report between
March 2002 and July 2004. During this
time, EPA developed a methodology;
collected data from federal, state, and
local sources; performed analyses;
coordinated with stakeholders; and
wrote this report. Data collection was
completed in early fall 2003, and select
analyses were updated in mid-2004.
This report is the second Report to
Congress required as part of PL. 106-
554. The first report was EPA's Report
to Congress-Implementation and
Enforcement of the Combined Sewer
Overflow Control Policy (EPA 833-R-
01-003).
PL. 106-554 also requires EPA to
develop and maintain a clearinghouse
of technologies for addressing the
impacts of CSO and SSO discharges.
In this chapter:
1.1 What are CSOs and
SSOs?
1.2 How is this Report
Organized?
Typical CSO outfall discharge following a
storm.
Photo: NJ Department of Environmental Protection
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Report to Congress on the Impacts and Control ofCSOs and SSOs
EPA expects that information
provided in this Report to Congress
will be the basis for the clearinghouse
when it is developed.
1.1 What are CSOs and SSOs?
In the United States, two types of
public sewer systems predominate:
combined sewer systems (CSSs)
and sanitary sewer systems (SSSs).
A CSS is a wastewater collection
system owned by a municipality (as
defined by Section 502(4) of the Clean
Water Act) that conveys domestic,
commercial, and industrial wastewater
and storm water runoff through a
single pipe system to a publicly-owned
treatment works (POTW).
An SSS is a wastewater collection
system owned by a municipality that
conveys domestic, commercial, and
industrial wastewater, and limited
amounts of infiltrated groundwater
and storm water to a POTW. Areas
served by SSSs often have a municipal
separate storm sewer system (MS4) to
collect and convey runoff from rainfall
and snowmelt.
1.1.1 CSOs
The term "CSO" refers to a discharge
from a CSS at a point prior to the
POTW treatment plant. CSOs
generally occur in response to wet
weather events; that is, during and
following periods when rainfall or
snowmelt drain to the CSS. Most CSSs
are designed to discharge flows that
exceed conveyance capacity directly to
receiving waterbodies, such as rivers,
streams, estuaries, and coastal waters.
CSSs can also back up into buildings,
including private residences. When
backups are caused by problems in
the publicly owned portion of a CSS,
they are considered unauthorized
discharges.
CSO discharges include a mix of
domestic, commercial, and industrial
wastewater, and storm water runoff.
As such, CSO discharges contain
human, commercial, and industrial
wastes as well as pollutants washed
from streets, parking lots, and other
surfaces. EPA's 1994 CSO Control
Policy (59 FR 18688) provides a
comprehensive national strategy
to ensure municipalities, NPDES
permitting authorities, water quality
standards authorities, EPA, and the
public to engage in a coordinated
planning effort to achieve cost-
effective CSO controls that ultimately
meet the requirements of the Clean
Water Act (EPA 1994a). The text of
the CSO Control Policy is provided
in Appendix A. In 2000, PL. 106-554
amended the Clean Water Act by
adding the following to Section 402:
(q)(l) Each permit, order, or
decree issued pursuant to this Act
after the date of enactment of this
subsection for a discharge from a
municipal combined storm and
sanitary sewer shall conform to the
CSO Control Policy signed by the
Administrator on April 11, 1994.
EPA's Report to Congress-
Implementation and Enforcement
of the Combined Sewer Overflow
Control Policy identified CSSs in
32 states (including the District of
Columbia) across nine EPA regions
(EPA 200la). As of July 2004, those 32
states had issued 828 permits to 746
communities.
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Chapter 1—Introduction
1.1.2SSOS
The term "SSO" refers to untreated or
partially treated sewage releases from
an SSS.
SSOs have a variety of causes,
including, but not limited to, severe
weather, blockages, line breaks,
power failures, lapses in sewer
system operation and maintenance,
inadequate sewer design and
construction, and vandalism. SSO
discharges typically contain a mix of
domestic, commercial, and industrial
waste. SSOs can pose challenging
public health and environmental
issues when they occur.
SSOs include those overflows that
reach waters of the United States, as
well as overflows out of manholes
and onto city streets, sidewalks, and
other terrestrial locations. A limited
number of municipalities have regular
SSO discharges from fixed points
within the sewer system. SSSs can back
up into buildings, including private
residences. When backups are caused
by problems in the publicly-owned
portion of an SSS, they are considered
SSOs.
SSOs that reach waters of the United
States are point source discharges,
and, like other point source discharges
from municipal SSSs, are prohibited
unless authorized by an National
Pollutant Discharge Elimination
System (NPDES) permit. Moreover,
SSOs, including those that do not
reach waters of the United States, may
be indicative of improper operation
and maintenance of the sewer
system, and thus may violate NPDES
permit conditions. EPA has focused
on SSO problems with compliance
assistance and enforcement activities
in accordance with the Compliance
and Enforcement Strategy Addressing
Combined Sewer Overflows and
Sanitary Sewer Overflows, issued
April 27, 2000 (EPA 2000b). In
addition, EPA is evaluating options
for improving NPDES permit
requirements for SSOs and municipal
SSSs.
EPAs 2000 Clean Watersheds Needs
Survey Report to Congress reported
15,582 municipal SSSs providing
wastewater collection, conveyance,
and treatment are presently operating
within the 50 states and the District
of Columbia (EPA 2003b). EPA also
identified an additional 4,846 satellite
SSSs providing only collection and
conveyance. Not all of these hold
NPDES permits (EPA 2003b). If not
properly maintained, satellite systems
have the potential to have an SSO
or to cause an SSO in downsewer
systems.
1.2 How is this Report
Organized?
The purpose of this report is
to respond to Congress with
a current characterization of
the volume, frequency, and location
of CSOs and SSOs, the extent of
human health and environmental
impacts caused by CSOs and SSOs,
the resources spent by municipalities
to address these impacts, and the
technologies used to address these
impacts. The report contains 10
chapters; the content and purpose of
which are summarized below.
Since the passage of the Clean Water Act in
1972,all levels of government have made
substantial investments in the nation's
wastewater infrastructure.
Photo: City of Chicago
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Sewer separation is one of the most often
used CSOcontrols.The separation project
shown here is underway in Louisville,
Kentucky.
Photo: Louisville-Jefferson County Metropolitan Sewer District
Chapter 2 summarizes the history of
regulatory efforts to control CSOs
and SSOs. It describes federal water
pollution control legislation, paying
particular attention to Clean Water Act
requirements for secondary treatment
and pretreatment, the Construction
Grants Program, and amendments to
the Clean Water Act made by P.L. 106-
554.
Chapter 3 describes the methodology
used to develop this Report to
Congress. In order to report on
impacts, resources spent to address
impacts, and the technologies
applied to control CSOs and SSOs,
EPA designed and implemented a
comprehensive approach to gather
the necessary data and information.
This effort included an extensive
literature search, site visits to EPA
regional offices and states, interviews
with state and local officials, an
experts workshop, and outreach to
stakeholders.
Chapter 4 characterizes the pollutants
present in CSO and SSO discharges
and identifies other watershed sources
of these pollutants. This chapter
describes the universe of CSS and
SSS permittees under the NPDES
program. The chapter also summarizes
information on the volume, frequency,
and location of CSOs and SSOs, as
well as the most common causes of
SSOs.
Chapter 5 describes the types of
environmental impacts attributable
to CSO and SSO discharges in terms
of water quality standards violations
and lost uses (i.e., closures of shellfish
beds and beaches). This chapter also
discusses the extent of environmental
impacts caused or contributed to by
CSO and SSO discharges. National
data are used to describe the extent of
environmental impacts. State and local
data are used to illustrate site-specific
examples of impacts.
Chapter 6 describes waterborne
diseases and other potential human
health impacts associated with
exposure to the pollutants found
in CSO and SSO discharges. The
chapter summarizes mechanisms
at the federal, state, and local levels
for reporting and tracking these
impacts. In addition, the chapter
describes different techniques used to
communicate the risk associated with
exposure to CSO and SSO discharges
and how these risks can be minimized
or prevented.
Chapter 7 summarizes federal and
state activities to regulate CSOs and
SSOs to minimize impacts associated
with discharges. The chapter reports
on the issuance of permits and
other enforceable orders requiring
control of CSOs or elimination of
SSOs. This chapter also summarizes
technical assistance provided by
federal and state governments to assist
municipalities in controlling CSOs
and SSOs.
Chapter 8 surveys the technologies
most widely used to control CSO and
SSO discharges, including: operation
and maintenance practices, sewer
system controls, storage facilities,
treatment technologies, and low-
impact development techniques.
The chapter also describes effective
combinations of technologies as
well as emerging practices that show
particular promise in the control of
CSOs and SSOs.
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Chapter 1—Introduction
Chapter 9 provides information on
the resources spent by municipalities
to control CSO and SSO discharges,
including a discussion of the
national investment in wastewater
infrastructure. Specific information
from select municipalities on
expenditures related to CSO and SSO
control is presented. The chapter
summarizes projected financial needs
for municipalities to meet current
regulatory requirements for CSO and
SSO control and discusses available
sources of funding to address impacts
ofCSOsandSSOs.
Chapter 10 summarizes report
findings and key considerations for
EPA in shaping future regulations and
program activities aimed at CSO and
SSO control.
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Chapter 2
Background
Municipal sewer systems
are an extensive and
valuable part of the
nation's infrastructure. In 2000, 16,202
wastewater treatment facilities and
21,264 sewer systems (both CSS and
SSS) were in operation in the United
States. These systems serve about 208
million people in the United States,
as reported in EPA's Clean Watersheds
Needs Survey 2000 Report to Congress
(EPA 2003b). EPA estimates that
publicly-owned sewer systems account
for about 724,000 miles of sewer pipe
and approximately 500,000 miles
of privately-owned pipes deliver
wastewater into these systems.
Much of the nation's wastewater
infrastructure is aging. Components
of some sewer systems date back
over 100 years, as evidenced by wood
and brick sewers still in operation in
some cities. A survey of 42 wastewater
utilities indicated the age of sewer
system components ranged from new
to 117 years, with an average age of
33 years (ASCE 1999). Over time,
municipalities have used a wide variety
of materials, design and installation
practices, and maintenance and
repair procedures, which has led to
considerable variability in the current
condition of sewer infrastructure.
This chapter provides a brief history
of sewer systems and wastewater
treatment in the United States, using
context provided by the Clean Water
Act. Additional information on federal
and state efforts related to the control
of CSOs and SSOs is presented in
Chapter 7.
2.1 What is the History of
Sewer Systems in the
United States?
In the pre-sewer era, human waste
was dumped into privy vaults and
cesspools, and storm water ran
into the streets or into surface drains.
Population increases during the 1800s,
particularly in urban areas, created
the need for more effective sanitary
systems. Between 1840 and 1880,
the percentage of Americans living
in urban areas rose from 11 percent
to 28 percent (Burian et al 1999).
This rapid urbanization resulted in
increased quantities of wastewater that
In this chapter:
2.1 What is the History of
Sewer Systems in the
United States?
2.2 What is the History of
Federal Water Pollution
Control Programs?
2.3 What is the Federal
Framework for CSO
Control?
2.4 What is the Federal
Framework for SSO
Control?
2.5 What is the Wet Weather
Water Quality Act?
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure 2.1
Typical Combined
Sewer System
Combined sewer systems are
designed to discharge directly to
surface waterbodies such as rivers,
estuaries,and coastal waters
during wet weather, when total
flows exceed the capacity of the
CSS or treatment plant.
Figure 2.2
Typical Separate
Sanitary and Storm
Sewer Systems
Sanitary sewer systems are
designed to collect and convey
wastewater mixed with limited
amounts of infiltration and inflow
to a treatment plant. A separate
storm sewer system is used in
many areas to collect and convey
storm water runoff directly to
surface waterbodies.
overwhelmed privy vaults and cesspool
systems. Consequently, municipalities
began installing sewer systems to
protect public health and to address
aesthetic and flooding concerns
(Melosi 2000). Little precedent existed
for the construction of underground
sewer systems, however, and engineers
were reluctant to experiment with
expensive capital works (Tarr 1996).
In 1858, the first comprehensive sewer
system was designed for the city of
Chicago (Burian et al. 1999). Extensive
construction of municipal sewer
systems did not start until the 1880s.
In the United States, municipalities
installed sewer systems using two
predominant design options:
• Combined sewer systems -
domestic, commercial, and
industrial wastewater, and storm
water runoff are collected and
conveyed in a single pipe system,
as shown in Figure 2.1; or
• Separate sanitary sewer and
storm sewer systems - domestic,
commercial, and industrial
wastewater, and storm water
runoff are collected and conveyed
using two separate systems of
pipe, as shown in Figure 2.2.
Combined sewer systems were less
expensive for municipalities that
needed both sanitary and storm
sewers, while SSSs were less expensive
2-2
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Chapter 2—Background
for municipalities that needed only a
wastewater collection system. Sanitary
sewers were sized to convey domestic,
commercial, and industrial wastewater,
and limited amounts of infiltrated
groundwater and storm water inflow.
Unlike CSSs, they were not intended
to collect large amounts of runoff
from wet weather events. In general,
large cities tended to construct CSSs,
given the flood control advantages
offered by such systems. By the end
of the 19 century, most of the large
urban areas with sewer systems had
CSSs. Smaller communities generally
pursued construction of separate
sanitary and storm sewers (Melosi
2000).
At the time, sanitary engineers
thought that both CSSs and SSSs
provided roughly equivalent health
protection, as neither design included
wastewater treatment (Tarr 1996).
This view was supported by an 1881
report to the National Board of
Health that recommended that design
choice be based on local conditions
and financial considerations (Hering
1977).
Construction of sewer systems greatly
improved local sanitary conditions
and in many cases reduced illness.
The direct discharge of untreated
wastewater to local receiving
waters, however, adversely impacted
downstream communities. During
the 1880s and 1890s, the rate of
typhoid deaths rose in cities with
drinking water intakes downstream
of untreated wastewater discharges.
Bacterial analysis confirmed the link
between sewage pollution in rivers
and epidemics of certain diseases
(Tarr 1996). Large outbreaks of
cholera, which claimed thousands
of lives, were also linked to sewage-
contaminated water supplies (Snow
1936). As a result, views on the safety
of discharging untreated wastewater
directly to receiving waters began
to shift toward the end of the 19*"
century.
As the need to provide wastewater
treatment was recognized, the major
design difference between CSSs and
SSSs became apparent. Although
combined sewers offered an efficient
means of collecting and conveying
storm water and wastewater, they
made treatment more difficult due to
the large variation in flows between
dry and wet weather conditions.
Sanitary sewer systems simplified
and lowered the cost of wastewater
treatment, due to significantly
smaller volumes of wet weather flows
(Burian et al. 1999). Nonetheless,
municipalities with CSSs often
continued to utilize and expand the
areas served by such systems (Tarr
1996).
Centralized municipal wastewater
treatment was still in its infancy in
the late 1800s (Burian et al. 1999). In
1892, only 27 municipalities treated
their wastewater; of these, 26 had SSSs.
2.1.1 Combined Sewers and CSOs
CSOs are primarily caused by wet
weather events (e.g., rainfall or
snowmelt), when the combined
volume of wastewater and storm
water entering the system exceeds the
capacity of the CSS or treatment plant.
When this occurs, combined systems
overflow directly to a receiving water.
Overflow frequency and duration
varies both from system to system and
Privy vaults and a water pump are located
side by side in this Pittsburgh neighborhood,
circa 1909.
Photo: Paul Underwood Kellog
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure 2.3
National Distribution of
Communities Served by
CSSs
CSSs are found throughout the
United States, but are most heavily
concentrated in the Northeast and
Great Lakes regions.
from outfall to outfall within a single
CSS. Some CSO outfalls discharge
infrequently, while others activate
every time it rains. When constructed,
CSSs were typically sized to carry
three to five times the average dry
weather flow. Thus, there is usually
considerable conveyance capacity
within a CSS during dry weather.
Discharges from a CSS during dry
weather, referred to as dry weather
overflows, are infrequent and are
prohibited under the NPDES program.
State and local authorities generally
have not allowed the construction of
new CSSs since the first half of the
20* century. As shown in Figure 2.3,
most of the communities served by
CSSs are located in the Northeast and
Great Lakes regions, while relatively
few are located in the Midwest,
Southeast, and Pacific Northwest.
Currently, 828 NPDES permits
authorize discharges from 9,348 CSO
outfalls in 32 states (including the
District of Columbia).
2.1.2 Sanitary Sewers and SSOs
SSOs include unauthorized discharges
from SSSs that reach waters of the
United States, as well as overflows out
of manholes and onto city streets,
sidewalks, and other terrestrial
locations. A limited number of
municipalities have SSO discharges
o»
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Chapter 2—Background
from fixed points within the sewer
system, similar to CSO outfalls.
SSOs, including those that do not
reach waters of the Unites States, may
be indicative of improper operation
and maintenance of the sewer system.
Causes of SSOs include, but are not
limited to:
• Blockages
• Structural, mechanical, or
electrical failures
• Collapsed or broken sewer pipes
• Insufficient conveyance capacity
• Vandalism
In addition, high levels of infiltration
and inflow (I/I) during wet weather
can cause SSOs. Many SSSs that
were designed according to industry
standards experience wet weather
SSOs because levels of I/I may exceed
levels originally expected; removal
of I/I has proven more difficult and
costly than anticipated; or the capacity
of the system has become inadequate
due to an increase in service
population without corresponding
system upgrades. SSSs are located
across the country, as presented in
Figure 2.4. EPA believes that all SSSs
have the potential to have occasional
SSOs.
Figure 2.4
National Distribution of
Communities Served by
SSSs
SSSs are located in all 50 states, but
are concentrated in the eastern
half of the United States and on the
west coast. SSSs are shown for ap-
proximately 75 percent of systems,
where locational data (latitude/
longitude) were available from EPA's
Permit Compliance System.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
San Francisco's CSO Oceanside Water
Pollution Control Plant treats an average
of 17 million gallons per day (mgd) during
dry weather and has 65 mgd of peak flow
capacity.
Photo: San Francisco Public Utilities Commission
2.2 What is the History of
Federal Water Pollution
Control Programs?
The desire for a federal water
pollution control program
increased steadily through the
first half of the 20* century. Congress
and the public became more aware
of the environmental and human
health impacts resulting from direct
discharges of untreated wastewater
to local receiving waters. Recognizing
the national interest in abating water
pollution for the benefit of water
supply and water resources, the 80*"
Congress stated:
"The pollution of our water
resources by domestic and
industrial wastes has become an
increasingly serious problem for
the rapid growth of our cities
and industries... Polluted waters
menace the public health through
the contamination of water and
food supplies, destroy fish and
game life, and rob us of other
benefits of our natural resources."
(Senate Report No. 462 of the 80th
Congress, 1948)
In 1948, Congress passed the
Federal Water Pollution Control Act
(FWPCA), P.L. 80-845, creating a
legislative basis for water pollution
control in the United States. The
original FWPCA was amended many
times (in 1956, 1961, 1965, 1966,
1970, 1972, 1977, 1981, and 1987).
Notably, the 1972 Amendments (P.L.
92-500), commonly known as the
Clean Water Act, restructured the
authority for water pollution control
and consolidated that authority in the
Administrator of the EPA. The Clean
Water Act provided a framework for:
• Prohibition of point source
discharges except as authorized by
a permit;
• Establishment of the National
Pollutant Discharge Elimination
System (NPDES), a regulatory
program that requires "point
source" dischargers, such as
municipal wastewater collection
and treatment plant operators,
to obtain a permit and meet
applicable regulations issued
under the Clean Water Act;
• Development of technology-
based effluent limits, based on
the pollutant reduction capacity
of demonstrable treatment
technologies, to be met by NPDES
permit holders; and
• Water quality standards and water
quality-based effluent limitations,
where technology-based limits
are inadequate to meet state water
quality standards.
As a result of investment in wastewater
treatment, the United States has
realized major improvements in
environmental quality and human
health. Widespread epidemics of
typhoid fever and cholera that
killed thousands of people in the
19* century and early 20* century
were brought under control and
have remained under control due to
disinfection of drinking water supplies
and advances in wastewater treatment.
2.2.1 Secondary Treatment
Many of the first wastewater treatment
facilities were designed to simply
separate solids and floating debris
from wastewater prior to discharge;
this process is often referred to as
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Chapter 2—Background
primary treatment (Rowland and
Held 1976). This modest level of
treatment, however, was unable
to offset increased pollutant loads
associated with rapidly growing urban
populations and associated increases
in the volume of wastewater generated.
An additional level of treatment was
needed to protect the quality of the
nation's waters.
The 1972 Clean Water Act provided
the first statutory requirement for
achievement of effluent limits based
on secondary treatment by POTWs.
Specifically, Section 301 of the Clean
Water Act required POTWs to meet
limits based on secondary treatment
by July 1, 1977. EPA developed
limits based on secondary treatment
to include maximum allowable
concentrations of key parameters as
well as percent removal requirements.
Limits based on secondary treatment
include maximum acceptable
concentrations for biochemical
oxygen demand measured over five
days (BOD5), total suspended solids
(TSS), and pH. Percent removal
requirements for BOD5 and TSS were
also included. Adjustments to percent
removal requirements are available, on
a case-by-case basis, for POTWs with
less-concentrated influent that may
prevent compliance with the standard
requirements (EPA2000a).
2.2.2 Construction Grants
In addition to establishing effluent
limits for POTWs, the FWPCA and
its amendments brought about
substantial investment in wastewater
treatment between the 1940s and the
present. The 1956 Amendments (PL.
84-660) established the Construction
Grants Program for the construction
of wastewater treatment facilities and
provided $150 million in funding for
the program. Additional construction
grant funding was authorized with the
1961, 1965, and 1966 amendments.
With passage of the Clean Water Act
in 1972, funding for the Construction
Grants Program dramatically
increased. EPAs Construction Grants
Program distributed $100.7 billion
(2002 dollars) to communities
between 1970 and 1995 (EPA 2000a).
The 1987 amendments to the Clean
Water Act transformed the financial
assistance from a grant program to
a loan program. The Construction
Grants Program was phased out
by 1991 and replaced by the State
Revolving Fund (SRF) program.
Federal funding provided a strong
impetus for constructing and
upgrading wastewater infrastructure.
The level of treatment provided at
POTWs improved substantially over
the last 50 years (EPA 2000a):
• 30 percent of POTWs (3,529
of 11,784) provided secondary
treatment in 1950.
• 72 percent of POTWs (10,052
of 14,051) provided secondary
treatment in 1968.
• 99 percent of 16,024 POTWs
provided secondary or greater
treatment, or were "no-discharge
facilities," in 1996.
High levels of compliance with
secondary treatment requirements
resulted in notable decreases in
pollutant loadings from POTWs, even
as the service population increased.
As an example, the amount of BOD5
discharged from POTWs declined by
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Some municipalities promote storm drain
stenciling as a storm water pollution
prevention measure.
about 23 percent between 1968 and
1996, despite a 35 percent increase in
influent loadings to POTWs during
the same period (EPA 2000a).
2.2.3 Pretreatment
In the mid-1980s, more than one-
third of all toxic pollutants entering
the nation's waters were discharged
from POTWs (EPA 1986a). POTWs
are not typically designed to remove
toxic pollutants, and in some cases
constituents in industrial wastewater
can actually interfere with the
removal of conventional pollutants
such as BOD5 and TSS. To address
the discharge of toxic pollutants,
EPA, pursuant to Clean Water Act
Section 307, established the National
Pretreatment Program. The National
Pretreatment Program requires that
industrial and commercial dischargers
treat or control toxic pollutants in
their wastewater prior to discharge to
a municipal sewer system.
The General Pretreatment Regulations
require all large POTWs (i.e.,
those designed to treat flows of
more than 5 million gallons per
day (mgd)) and smaller POTWs
with significant industrial users to
establish local pretreatment programs.
These local programs implement
national pretreatment standards and
requirements in addition to any more
stringent local requirements necessary
to protect site-specific conditions.
More than 1,500 POTWs have
developed and are implementing local
pretreatment programs designed to
control discharges from approximately
30,000 significant industrial users.
The National Pretreatment Program
has made great strides in reducing the
discharge of toxic pollutants to sewer
systems and to waters of the United
States (EPA 1999a).
2.2.4 Wet Weather
Initial implementation of the Clean
Water Act during the 1970s and 1980s
focused on discharges from traditional
point sources of pollution, such as
POTWs and industrial facilities.
Beginning in the late 1980s, attention
shifted to wet weather sources of
pollution. Under the NPDES program,
four program areas address wet
weather discharges: CSOs, SSOs, storm
water, and concentrated animal feeding
operations (CAFOs).
Storm Water
EPA published Phase I of the NPDES
Storm Water Program in 1990 (55
FR 47990). Phase I applies to large
dischargers; that is, those associated
with industrial activities, municipal
separate storm sewer systems
serving 100,000 people or more, and
construction projects disturbing
more than five acres of land. In 1999,
EPA published the Phase II Final
Rule, which requires NPDES permit
coverage for storm water discharges
from smaller sources, including cities
and towns in urban areas with separate
storm sewer systems serving fewer
than 100,000 people, and smaller
construction projects that disturb less
than five acres (64 FR 68722).
CAFOs
CAFOs are point sources, as defined
by Clean Water Act Section 502(14).
On February 12, 2003, EPA published
the Concentrated Animal Feeding
Operations Rule to ensure that manure
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Chapter 2—Background
and wastewater from CAFOs are
properly managed to protect the
environment and public health (68 FR
7175).
2.2.5 Watershed-Based
Permitting
On December 17, 2003, EPA
published the Watershed-Based
NPDES Permitting Implementation
Guidance (EPA 2003c). Watershed-
based permitting under the NPDES
program emphasizes addressing
all stressors (including CSOs and
SSOs) within a watershed, rather
than individual pollutant sources on
a discharge-by-discharge basis. The
watershed-based permitting approach
is supported by EPA as a cost-effective
mechanism for improving water
quality and meeting watershed goals.
The approach builds on watershed
policy and guidance developed during
the 1990s: EPA's Watershed Strategy,
Watershed Framework, and Clean
Water Action Plan (EPA 1994b, 1996a,
EPA and USDA 1998). In addition,
the approach fulfills commitments
articulated in recent initiatives such as
EPA's Trading Policy and Watershed-
Based Permitting Policy Statement
(EPA 2003d, 2003e).
Watershed-based permitting can
encompass a variety of activities
ranging from synchronizing NPDES
permits within a basin to developing
water quality-based effluent limits
using a multiple discharger modeling
analysis. Within a broader watershed
management system, the watershed-
based permitting approach is a tool
that can assist with implementation
activities such as monitoring,
reporting, and assessment.
2.3 What is the Federal
Framework for CSO
Control?
CSOs are point source
discharges and are subject to
NPDES permit requirements.
CSOs are not subject to limits based
on secondary treatment requirements
otherwise applicable to POTWs.
Permits for CSOs must include
technology-based effluent limits,
based on the application of best
available technology economically
achievable (BAT) for toxic and
non-conventional pollutants and
best conventional pollutant control
technology (BCT) for conventional
pollutants. Additionally, like all
NPDES permits, permits authorizing
discharges from CSO outfalls must
include more stringent water quality-
based requirements, when necessary,
to meet water quality standards. The
development of the federal framework
to address CSOs is described in detail
below.
2.3.1 CSO Case Law
In 1980, the U.S. Court of Appeals
for the D.C. Circuit accepted EPA's
interpretation of the Clean Water
Act that discharges at CSO outfalls
are not discharges from POTWs
and thus are not subject to the
limits based on secondary treatment
standards otherwise applicable to
POTWs (Montgomery Environmental
Coalition vs. Costle, 46 F2d 568 (D.C.
Cir. 1980)). Following this decision,
EPA and states renewed their focus
on permit requirements for CSO
discharges under the NPDES program.
The sewer utility serving Louisville, Kentucky,
has restructured its organization to
coordinate CSO control needs with other
water quality improvement programs as part
of an effort to move toward watershed-based
permitting.
Photo: Louisville-Jefferson County Metropolitan Sewer District
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Report to Congress on the Impacts and Control ofCSOs and SSOs
A CSO outfall in Wilmington, Delaware.
Photo: Wilmington Department of Public Works
2.3.2 The National CSO Control
Strategy and the MAG
In 1989, EPA issued the National
CSO Control Strategy (54 FR
37371). The National CSO Control
Strategy encouraged states to develop
statewide permitting strategies to
ensure all CSOs were subject to an
NPDES permit and recommended six
minimum measures for CSO control;
additional controls could be required
as necessary. As EPA, states, and
municipalities worked to implement
the National CSO Control Strategy in
the early 1990s, the impacts of CSOs
(discussed in Chapters 5 and 6 of this
report) continued to receive national
attention. Environmental interest
groups pushed for further action, while
municipal organizations, concerned
that the National CSO Control Strategy
did not provide sufficient clarity,
sought a consistent national approach
to CSO control. In response to these
concerns, EPA formed a Management
Advisory Group (MAG) in 1992.
The MAG included representatives
from states, municipalities, industry
associations, and environmental
interest groups.
2.3.3 The CSO Control Policy
EPA published the CSO Control Policy
on April 19, 1994 (59 FR 18688). The
purpose of the CSO Control Policy was
twofold: 1) to elaborate on EPA's 1989
National CSO Control Strategy; and
2) to expedite compliance with Clean
Water Act requirements. The policy
sought to minimize adverse impacts
from CSOs on water quality, aquatic
biota, and human health (EPA 1994a).
EPA's CSO Control Policy assigns
primary responsibility for its
implementation and enforcement
to NPDES authorities and water
quality standards authorities. This
policy also established objectives for
CSO communities: 1) to implement
the nine minimum controls (NMC)
and submit documentation on NMC
implementation; and 2) to develop
and implement a long-term control
plan (LTCP). Implementation status
of the NMC and LTCPs is presented
in Chapter 7. More information
on the CSO Control Policy is
provided in EPA's Report to Congress-
Implementation and Enforcement of
the Combined Sewer Overflow Control
Po/zcy(EPA2001a).
2.4 What is the Federal
Framework for SSO
Control?
SSOs that reach waters of the
United States are point source
discharges and, like other point
source discharges from municipal
SSSs, are prohibited unless authorized
by an NPDES permit. Moreover, SSOs,
including those that do not reach
waters of the United States, may be
indicative of improper operation and
maintenance of the sewer system,
and thus may violate NPDES permit
conditions. In the 1989 National CSO
Control Strategy, EPA explained that:
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Chapter 2—Background
"sanitary sewer systems must adhere
to the strict design and operational
standards established to protect the
integrity of the sanitary sewer system
and wastewater treatment facilities."
In 1994, a number of municipalities
asked EPA to establish an SSO
Federal Advisory Committee
(FAC) of key stakeholders to make
recommendations on how the NPDES
program should address SSOs. The
municipalities indicated a desire for
greater national clarity, consistency
in NPDES requirements applicable
to SSOs, and a workable regulatory
framework. Five general stakeholder
groups were represented in the SSO
FAC: sanitary sewer system operators,
SSO-related health professionals,
state regulatory agencies, technical
professionals, and environmental and
citizen groups.
In 1995, EPA chartered an Urban Wet
Weather Flows FAC with stakeholder
representation to address cross-
cutting issues associated with wet
weather discharges (i.e., CSOs, SSOs,
and storm water). The Urban Wet
Weather Flows FAC formed its SSO
Subcommittee by reconvening the
SSO FAC established in 1994. The
SSO Subcommittee was tasked with
developing a framework for addressing
SSOs and their impacts through
regulatory and non-regulatory actions.
Between 1995 and 1999, the SSO
Subcommittee held 12 meetings and
developed a number of documents,
including a series of issue papers
and a draft comprehensive guidance
document. In January 2001, EPA
prepared a notice of proposed
rulemaking related to SSOs, which
was withdrawn for review before it
was published in the Federal Register.
EPA is considering various options for
moving forward.
2.5 What is the Wet Weather
Water Quality Act?
In December 2000, as part of the
Consolidated Appropriations Act
for Fiscal Year 2001 (PL. 106-554),
Congress amended the Clean Water
Act by adding Section 402(q). This
amendment is commonly referred to
as the Wet Weather Water Quality Act
of 2000. Section 402(q) requires that
each permit, order, or decree issued
pursuant to the Clean Water Act after
the date of enactment for a discharge
from a municipal combined sewer
system shall conform to the CSO
Control Policy. It authorized a $1.5-
billion grant program for controlling
CSOs and SSOs. Section 402(q) also
required EPA to issue guidance to
facilitate the conduct of water quality
and designated use reviews for CSO
receiving waters. EPA issued this
guidance on August 2, 2001 (EPA
2001b).
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Chapter 3
Methodology
This chapter documents the
methodology EPA used
to prepare this Report to
Congress. It presents EPA's study
objectives and analytical approach,
and summarizes the steps EPA has
taken to compile information on the
impacts and control of CSOs and
SSOs. This chapter describes EPA's
data sources, explains information
collection methods, and outlines the
steps EPA took to involve stakeholders
in the development of this report.
The chapter also summarizes data
considerations and quality assurance
measures used to enhance the accuracy
and precision of results.
3.1 What Study Objectives and
Approach Did EPA Use to
Prepare this Report?
The overall objective for
this report is to respond
to Congress with a current
characterization of the volume,
frequency, and location of CSOs and
SSOs; the extent of human health
and environmental impacts caused by
CSOs and SSOs; the resources spent
by municipalities to address these
impacts; and the technologies used to
address these impacts. Some new data
were obtained through interviews in
the development of this report, but
EPA did not undertake surveys or
field monitoring to characterize CSOs,
SSOs, and their impacts. Instead, EPA
primarily emphasized the collection,
compilation, and analysis of existing
data.
EPA used a two-tiered approach
to address the questions posed by
Congress. The first tier focused on
national assessments, drawing on
existing data collected by EPA and
other federal agencies to the fullest
extent possible. These data were
supplemented with select data from
non-governmental organizations
that were also national in scope.
The second tier focused on the use
of anecdotal data to provide site-
specific examples of impacts, costs,
and technology applications, and
to demonstrate the significance of
CSOs and SSOs at the local level. Site-
specific examples were largely drawn
from state and local interviews and
reports.
In this chapter:
3.1 What Study Objectives
and Approach Did EPA
Use to Prepare this
Report?
3.2 What Data Sources Were
Used?
3.3 What Data Were
Collected?
3.4 How Were Stakeholders
Involved in the
Preparation of this
Report?
3.5 What Data
Considerations Are
Important?
3.6 What Quality Control
and Quality Assurance
Protocols Were Used?
3.7 Summary
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Clean Watersheds Needs
Survey 2000
Report to Congress
3.2 What Data Sources Were
Used?
EPA developed a comprehensive
list of potential data
sources that could be used
to characterize CSOs and SSOs,
including environmental and human
health impacts from the discharges,
technologies used to control the
discharges, and the costs of the control
measures. This list included:
• Federal data sources
• NPDES authority and other state
program data sources
• Community-level data sources
• Non-governmental organization
data sources
The following sections describe
specific data sources EPA used to
develop this report.
3.2.1 Federal Data Sources
EPA researched its own files and
library of CSO- and SSO-related
documents for data that could be used
to characterize CSOs and SSOs. Data
and reports relevant to CSOs and
SSOs developed by EPAs permitting,
compliance and enforcement, research
and development, and water quality
assessment programs were among
those reviewed. Specific EPA data
sources used in the analysis for this
Report to Congress include:
Beaches Environmental Assessment and
Coastal Health (BEACH) Program.
The BEACH Program focuses
on improving public health and
environmental protection programs
for beachgoers and providing the
public with information about the
quality of beach water.
Clean Watersheds Needs Survey
(CWNS). The CWNS summarizes
estimated capital costs for water
quality projects including projects to
control CSOs and SSOs.
Enforcement and Compliance Docket
(ECD). The ECD is the central archive
for all documents related to EPAs
enforcement and compliance activities.
It contains regulatory, case settlement,
and other policy related information.
EPAs 2001 Report to Congress-
Implementation and Enforcement of
the Combined Sewer Overflow Control
Policy. The 2001 Report to Congress
provides a comprehensive national
inventory of active CSO permits.
Government Performance and Results
Act (GPRA). EPA selected the CSO
program as a GPRA pilot program
for tracking programmatic benefits in
1997.
Municipal Technology Fact Sheets. EPA
maintains a series of more than 100
technology fact sheets, including more
than 20 with application to the control
of CSOs and SSOs.
National Water Quality Inventory
(NWQI). The biennial NWQI Report
to Congress is the primary vehicle for
informing Congress and the public
about general water quality conditions
in the United States.
Office of Research and Development
(ORD) projects. ORD works with
industry, universities, and other
agencies to develop technologies and
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Chapter 3—Methodology
techniques for protecting the nation's
freshwater and coastal resources and
human health.
Permit Compliance System (PCS). PCS
provides information on point sources
holding NPDES permits, including
permit issuance and expiration
dates, discharge limits, and discharge
monitoring data.
EPA also researched the programs
and files of other federal agencies to
ensure that relevant data from other
federal programs and activities were
assessed and included in this report,
as appropriate. The agencies consulted
included:
• Centers for Disease Control and
Prevention (CDC)
• Congressional Budget Office
(CBO)
• Government Accounting Office
(GAO)
• National Institutes of Health
(NIH)
• National Oceanic and
Atmospheric Administration
(NOAA)
• United States Geological Survey
(USGS)
3.2.2 NPDES Authority and Other
State Program Data Sources
Individual NPDES authorities and
associated state programs were the
primary sources of data on the
location of CSO outfalls as well as the
frequency, volume, and cause of SSO
events. EPA conducted interviews with
states to assess the availability of data.
State program data and interviews
with program staff were also used to
identify site-specific CSO- and SSO-
related examples of environmental
and human health impacts such as fish
kills, beach closures, and outbreaks of
waterborne disease.
3.2.3 Community-Level Data
Sources
EPA identified relevant community-
level data to supplement the national
data and drew on local planning
and monitoring studies, such as
CSO ETCPs, to illustrate site-specific
impacts and common technologies
used to control CSOs and SSOs.
Municipalities were interviewed
to obtain additional data to
characterize the volume, frequency,
and constituents of CSO and SSO
discharges; to identify the types of
controls implemented and results
achieved; and to quantify the resources
spent.
3.2.4 Non-Governmental
Organization Data Sources
EPA also reviewed reports prepared by
non-governmental organizations that
contained national-level data relevant
to the objectives of this report. These
included:
• American Public Works
Association (APWA)
• American Society of Civil
Engineers (ASCE)
• Association of Metropolitan
Sewerage Agencies (AMSA)
• The Ocean Conservancy
• Water Environment Federation
(WEF)
• Water Environment Research
Foundation (WERF)
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Report to Congress on the Impacts and Control ofCSOs and SSOs
3.3 What Data Were Collected?
Data collection involved
identification and
compilation of existing
information. The primary data sources
for this report were federal databases
and reports as well as interviews with
states and municipalities. In addition,
EPA performed a comprehensive
literature search and applied national
assessment models, where appropriate.
In compliance with the Paperwork
Reduction Act, EPA prepared and
submitted Information Collection
Request 2063.01, which was approved
by OMB on September 16, 2002
(OMB No. 2040-0248).
The following sections describe data
collection and the key assessments
carried out by EPA.
3.3.1 Characterization of CSOs and
SSOs
This report characterizes CSOs and
SSOs by addressing the following key
questions:
• What pollutants are in CSOs and
SSOs?
• What factors influence the
concentrations of these pollutants in
CSOs and SSOs?
• What other point and nonpoint
sources might discharge these
pollutants to waterbodies receiving
CSOs and SSOs?
• What is the universe of combined
sewer systems?
• What are the characteristics of
CSOs?
• What is the universe of sanitary
sewer systems?
• What are the characteristics of
SSOs?
• How do the volumes and loads from
CSOs and SSOs compare to those
from other municipal point sources?
To address these questions EPA used
NPDES permit files, state databases
for tracking CSO and SSO events, and
interviews with state and municipal
officials. Specific efforts included
updating data on the location of CSSs
and CSO outfalls from the 2001 Report
to Congress-Implementation and
Enforcement of the Combined Sewer
Overflow Control Policy (EPA 2001a),
and compiling SSO volume, frequency,
and cause data. This allowed
assessment of:
• Pollutants found in CSOs and
SSOs
• Location of CSSs and individual
CSO outfalls
• Volume and frequency of CSOs
and SSOs
• Causes of SSOs
• Comparison of pollutant loads
from CSOs and SSOs with other
municipal point sources
EPA relied on existing Agency data
systems wherever possible. These
include PCS, the CWNS, and NWQI.
EPA data systems were the principal
source of information used to locate
CSSs, CSO outfalls, and SSSs. Data
on the concentration of pollutants
found in CSO and SSO discharges
were developed from a number of
sources, including engineering and
scientific literature, EPA studies,
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Chapter 3—Methodology
municipal reports including CSO
LTCPs, and interviews with municipal
sewer system owners and operators.
EPA applied the GPPvACSO model
to calculate the annual volume
of CSOs. Documentation of the
GPRACSO model is included as
Appendix E of this report. EPA used
statistical techniques to develop
national estimates of the frequency
and volume of SSOs based on data
reported electronically by states.
Documentation of the statistical
techniques is included in this report as
Appendix G.
3.3.2 Extent of Environmental
Impacts Caused by CSOs and
SSOs
This report's analysis of the extent
of environmental impacts caused
by CSOs and SSOs addresses the
following key questions:
• What is EPA's framework for
evaluating environmental impacts?
• What overall water quality impacts
have been attributed to CSO
and SSO discharges in national
assessments?
• What impacts on specific designated
uses have been attributed to CSO
and SSO discharges in national
assessments?
• What overall water quality impacts
have been attributed to CSO and
SSO discharges in state and local
assessments?
• What impacts on specific designated
uses have been attributed to CSO
and SSO discharges in state and
local assessments?
• What factors affect the extent of
environmental impacts caused by
CSOs and SSOs?
EPA used federal reports and data as
the primary bases for reporting on
environmental impacts from CSOs
and SSOs on a national level. The
assessment included identification
of water quality impairments and
environmental impacts associated with
CSOs and SSOs with respect to:
• Impaired stream segments
• Impaired lakes
• Impaired estuaries
• Impaired ocean shoreline
• Impaired Great Lakes shoreline
• Beach closures
• Shellfish bed closures
EPA also reviewed national resource
assessments from NOAA and non-
governmental organizations such as
the Ocean Conservancy.
CSS location and individual CSO
outfall information published
in the 2001 Report to Congress-
Implementation and Enforcement of
the Combined Sewer Overflow Control
Policy was updated for this Report to
Congress by contacting states and EPA
regions to confirm active CSO permit
data. The data system developed as
part of the 2001 report effort contains
latitude and longitude information for
over 90 percent of the CSO outfalls
currently permitted under the NPDES
program. Having the latitude and
longitude of the CSO outfalls allowed
individual permitted outfalls to be
associated with specific waterbody
segments (called "reaches") within
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Water quality data from state 305(b) reports
were used in gathering information on the
environmental impacts of CSOs.
Photo: P. Macneill
the National Hydrography Dataset
(NHD). The NHD is a comprehensive
set of digital spatial data of surface
water features that enables analysis
of water-related data in upstream
and downstream order. Associating
CSO outfall locations with the NHD-
indexed assessed waters allowed for
comparison of the outfalls to known
impairments reported by states, as
required under Clean Water Act
Sections 303(d) and 305(b), and to the
location of protected resources and
sensitive areas. Additional detail on the
CSO analysis using the NHD-indexed
assessed waters is documented in
Appendix F.
SSOs are generally considered
unpermitted discharges, and SSO
locations are not typically included
in NPDES permits. As described in
Chapter 4, SSOs occur for a variety of
reasons and at many locations within
the sewer system, including manholes,
roadways, and pump stations. Further,
some SSOs discharge to land and not
to waters of the United States. For
these reasons, it was not possible to
conduct a parallel analysis for SSOs
using the NHD. EPA, however, did
develop a simple model for estimating
the likely impact of SSO events on
streams and rivers based on reasonable
assumptions about SSO event
duration, pollutant concentrations, and
waterbody characteristics. Additional
detail on the model is provided in
Appendix H.
National level assessments are unable
to convey the circumstances that
surround an individual CSO or SSO
event, the nature of site-specific
environmental impacts, and the
consequences with respect to water
quality criteria and designated uses.
To account for these localized impacts,
EPA used state and community-
level data to document site-specific
environmental impacts including
water quality standards violations,
shellfish bed closures, and fish kills.
These examples are not comprehensive
but are presented to illustrate the
potential of CSOs and SSOs to
cause or contribute to impacts and
impairments.
3.3.3 Extent of Human Health
Impacts Caused by CSOs and
SSOs
This report's analysis of the extent of
human health impacts caused by CSOs
and SSOs addresses the following key
questions:
• What pollutants are present in
CSOs and SSOs that can cause
human health impacts?
• What exposure pathways and
reported human health impacts are
associated with CSOs and SSOs?
• Which demographic groups face the
greatest risk of exposure to CSOs
and SSOs?
• Which populations face the greatest
risk of illness from exposure to the
pollutants present in CSOs and
SSOs?
• How are human health impacts
from CSOs and SSOs prevented,
communicated, and mitigated?
• What factors contribute to
information gaps in identifying
and tracking human health impacts
from CSOs and SSOs?
3-6
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Chapter 3—Methodology
• What new assessment and
investigative activities are
underway?
EPA began its effort to document
human health impacts from CSOs
and SSOs with a literature review. EPA
searched on-line databases including
PubMed, Toxline, LexisNexis, and
the Washington Research Libraries
Consortium for relevant reports and
articles. A series of waterborne disease
outbreak case studies developed from
published literature is provided in
Appendix I. EPA gathered data on the
general incidence and characteristics
of waterborne diseases as well as on
other impacts associated with the
pollutants found in CSO or SSO
discharges. The primary source of
data on the incidence of waterborne
disease in the United States is a joint
surveillance system operated by the
CDC, EPA, and the Council of State
and Territorial Epidemiologists (CDC
2002). Summaries of data collected
by CDC are published periodically
and divided into waterborne-disease
outbreaks resulting from drinking
water, recreational waters, or, in some
cases, cruise ships. EPA also reviewed
reports from non-governmental
organizations for data related to
human health impacts.
EPA identified experts in the fields
of epidemiology, public health
policy, and waterborne disease
research and invited them to attend
a workshop in August 2002. Experts
represented EPA, CDC, local health
departments, and academia. This
workshop did not constitute an
advisory committee under the Federal
Advisory Committees Act. Rather, it
solicited individual expert opinions
and provided a forum for information
exchange related to this Report to
Congress. EPA shared the results of its
initial data collection at this workshop,
received feedback on and refined the
study methodology, and sought to
ensure that gaps and redundancies in
the research effort did not exist. An
abstract of this workshop is provided
in Appendix B; the summary of this
workshop was published separately
(EPA2002b).
EPA also estimated the illness burden
resulting from exposure to CSOs
and SSOs at beaches recognized by
state authorities using data from the
BEACH Program's annual survey
(BEACH Survey) and other sources.
EPA analyzed data from responses
to the 1999-2002 BEACH Surveys
including the number of CSO and
SSO events, number of swimmers,
bacterial concentrations, and CSO
and SSO event duration. An illness
rate derived by Cabelli et al. (1983)
and Dufour (EPA 1984a) was applied
to estimate the number of swimmers
who contract gastrointestinal
illnesses. Additional details describing
this methodology are included in
Appendix J.
EPA also conducted interviews with
public health personnel, including
state or territorial epidemiologists and
local public health officials. States and
communities were selected from each
EPA region in an attempt to ensure
geographic, climatic, and population
variability among communities
interviewed. Nevertheless, the sample
is intentionally biased, targeting
communities that were likely to have
health data related to CSOs and SSOs,
or that employed noteworthy water
quality monitoring or waterborne
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Report to Congress on the Impacts and Control ofCSOs and SSOs
disease outbreak tracking techniques.
The results of the interviews are
provided in Appendix I.
3.3.4 Evaluation of Technologies
Used by Municipalities to
Address Impacts Caused by
CSOs and SSOs
This report's evaluation of the
technologies used by municipalities
to address impacts caused by CSOs
and SSOs addresses the following key
questions:
• What technologies are commonly
used to address CSOs and SSOs?
• How do CSO and SSO controls
differ?
• What are effective technology
combinations?
• What are emerging technologies for
CSO and SSO control?
EPA conducted a literature review
and collected reports on CSO and
SSO abatement efforts to evaluate
technologies used by municipalities
to address the impacts of CSO and
SSO discharges. These data included
existing EPA fact sheets, technical
reports covering relevant research, and
wet weather demonstration studies.
EPA also reviewed technical guidance
manuals developed by states, as well
as documentation of local programs,
including CSO LTCPs. The literature
review was supplemented with
discussions of CSO and SSO programs
in interviews with municipal sewer
system owners and operators.
The analysis conducted by EPA
included:
• Development of 23 technology
descriptions, included as
Appendix L of this report, that
summarize available technologies
and the factors that influence their
applicability and effectiveness.
• Identification of common and
promising technologies used by
municipalities to control CSOs
and SSOs.
EPA and non-EPA experts were
called upon to provide peer review
of technology descriptions, costs,
and performance. It is anticipated
that technology data gathered and
presented in this report's technology
descriptions will support development
of the technology clearinghouse
required by the Wet Weather Water
Quality Act of 2000 (P.L.106-554).
3.3.5 Assessment of Resources
Spent by Municipalities to
Address Impacts Caused by
CSOs and SSOs
This report's assessment of resources
spent by municipalities to address
impacts caused by CSOs and SSOs
addresses the following key questions:
• What federal framework exists for
evaluating resources spent on CSO
and SSO control?
• What are the past investments in
wastewater infrastructure?
• What has been spent to control
CSOs?
• What has been spent to control
SSOs?
• What does it cost to maintain sewer
systems?
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Chapter 3—Methodology
• What are the projected costs to
reduce CSOs?
• What are the projected costs to
reduce SSOs?
• What mechanisms are available for
funding CSO and SSO control?
EPA used several of its own reports
and reviewed data from other federal
agencies (e.g., CBO, GAO, and
Census Bureau), states, and non-
governmental organizations to assess
the national investment in wastewater
infrastructure and future needs. EPA
also reviewed data collected for the
2000 CWNS (EPA 2003b). EPA used
a variety of reports to quantify the
resources spent by municipalities to
control CSOs and SSOs, including:
• EPAs 1996 Clean Water Needs
Survey (EPA 1997a) and 2000
CWNS (EPA 2003b)
• EPAs Clean Water and Drinking
Water Infrastructure Gap Analysis
(EPA 2002a)
• Clean Water State Revolving Fund
(CWSRF) records
• Negotiated enforcement actions
• Interviews with municipal owners
and operators of sewer systems
• CSO LTCPs
• Recent AMSA, ASCE, and WERF
reports
EPA also used a variety of sources
to assess available mechanisms for
funding CSO and SSO control,
including:
• EPAs Clean Water and Drinking
Water Infrastructure Gap Analysis
(EPA 2002a)
• EPAs 2001 Report to Congress-
Implementation and Enforcement
of the Combined Sewer Overflow
Control Policy (EPA 200la)
• EPAs Fact Sheet: Financing Capital
Improvements for SSO Abatement
(EPA 200 Ic)
• EPAs Combined Sewer Overflows:
Guidance for Funding Options
(EPA 1995a)
• GAO reports
• CSO LTCPs
3.4 How Were Stakeholders
Involved in the Preparation
of this Report?
EPA consulted and worked with
a broad group of stakeholders
for this report. EPA conducted
site visits to several EPA regions
and six states; developed a series
of 23 technology descriptions in
cooperation with municipalities; and
sought review of sections of the report
from experts internal and external
to EPA. States and municipalities
featured in this Report to Congress
were provided the opportunity
to review information specifically
pertaining to them.
Throughout 2002 and 2003, EPA
met with representatives from key
stakeholder groups such as AMSA,
NRDC, and WEE During these
meetings, EPA presented an overview
of the congressional directive and the
Agency's planned response. EPA then
solicited feedback on its progress.
The comments and suggestions of the
stakeholder groups were incorporated
into the preparation of this report.
In 1999, North Bergen Municipal Utilities
installed numerous mechanical screen
bars and netting systems to control solids
and floatables in CSOs. The facilities cost
$3.3 million and annually cost $57,373 to
operate and maintain (2002 dollars).
Photo: NJDEP
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Report to Congress on the Impacts and Control ofCSOs and SSOs
As described in Section 3.3.3, EPA
facilitated a workshop for public
health experts in Arlington, Virginia.
Experts represented EPA, CDC, local
health departments, and academia.
Observers of the workshop included
representatives of many stakeholder
groups.
EPA also sponsored stakeholder
meetings during development of
this report in Washington, DC (June
2003), and in Huntington Beach, CA
(July 2003). Participants included
representatives from EPA regions;
states; municipal sewer system owners,
operators, and consultants; national
and local environmental organizations;
professional associations; and public
health experts. The purpose of these
meetings was to:
• Provide a preliminary description
of the report methodology and
findings
• Discuss the implications of
preliminary findings
• Describe data availability and
limitations
• Solicit additional data on impacts,
costs, and technologies
EPA presented preliminary data on
all aspects of the report, received
comments on data sources and
data interpretation, and received
input on the context within which
these findings should be viewed. A
summary of the stakeholder meetings
is provided in Appendix B of this
report. EPA also made presentations
at numerous national meetings and
conferences to provide progress
reports and updates to stakeholders.
3.5 What Data Considerations
Are Important?
The information collection
strategy used to support
this report includes several
important data considerations. First
and foremost, EPA based this report
on the collection, compilation,
and analysis of existing data and
program information. No surveys
or field monitoring were conducted
to quantify pollutant concentrations
or environmental and human health
impacts. Similarly, EPA did not
undertake new research or analysis
in the assessment of technologies or
evaluation of costs.
Another important data consideration
is state-to-state differences in the
definition of "CSO event" and "SSO
event" related to threshold volumes
and duration of events that last
beyond midnight or for more than 24
hours. EPA also found that wastewater
backups into buildings, including
private residences, are not typically
tracked by or reported to NPDES
authorities.
A third consideration is that often
the pollutants present in CSOs and
SSOs have numerous sources within a
given watershed. These sources include
municipal wastewater treatment plants,
storm water runoff, decentralized
wastewater treatment systems,
runoff from agricultural areas, and
wildlife and domesticated animals.
It can be difficult, if not impossible,
to differentiate environmental and
human health impacts caused by CSO
and SSO discharges from those caused
by these other sources.
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Chapter 3—Methodology
A fourth consideration is the potential
underreporting of waterborne disease
outbreaks. Existing systems for
tracking these outbreaks often lack
sufficient information on the cause
of the outbreak to establish whether
CSOs or SSOs are a suspected source.
A final data consideration is that
the nature of many CSO and SSO
control activities makes it difficult
to separate their costs from routine
municipal wastewater infrastructure
expenditures. Further, local and state
governments currently fund the
majority of wastewater infrastructure
costs. Mechanisms for compiling
comprehensive national level
information on expenditures on CSO
and SSO control do not exist. The
CWSRF is the most comprehensive
source of information on state
and local spending on wastewater
projects. There are, however, several
important limitations to using data
from the CWSRF. First, operation
and maintenance (O&M) costs are
not reported. Second, many CSO
communities do not participate in the
CWSRF. Third, the CWSRF has no
separate accounting categories for SSO
control. Moreover, although many
communities and states are making
concerted efforts to report additional
needs for CSO and SSO control, very
few report the cost of implementing
technologies.
Although the above considerations
shaped the approach used to develop
this report, the basic objectives—to
respond to Congress with an accurate
characterization of the volume,
frequency, and location of CSOs and
SSOs; the extent of human health
and environmental impacts caused by
CSOs and SSOs; the resources spent
by municipalities to address these
impacts; and the technologies used to
address impacts—never varied.
3.6 What Quality Control
and Quality Assurance
Protocols Were Used?
EPA applied a detailed data
verification and interpretation
process following data
collection. Federal and state data
sets were evaluated for missing and
inconsistent data. Follow-up phone
calls were made to data providers to
verify the accuracy and completeness
of EPAs records. Likewise, site-specific
examples of impacts and technology
application were reviewed by local
officials.
The data taken from reports prepared
by external sources, such as ASCE and
AMSA, were not obtained directly by
EPA and were used as reported. These
data were not subjected to the same
quality control as data collected and
compiled directly by EPA.
3.7 Summary
Chapters 4 through 9 provide
a detailed assessment of the
data and materials collected
in support of this Report to Congress.
The compilation of existing data led to
development of several new analyses
that previously did not exist. These
include:
• National estimates of the
frequency and volume of SSOs
• Analysis of causes of SSOs
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Report to Congress on the Impacts and Control ofCSOs and SSOs
• National modeling of SSO events
to estimate violations of water
quality standards
• Updated CSO permit information
with latitude and longitude for
over 90 percent of CSO outfalls
• Analysis linking CSO outfall
locations with impaired waters and
sensitive areas through the NHD
• Modeling to estimate the number
of gastrointestinal illnesses
resulting from exposure to CSOs
and SSOs at BEACH Survey
beaches
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Chapter 4
Characterization of
CSOs and SSOs
Consistent with the
congressional directive,
this chapter provides a
comprehensive description of
CSOs and SSOs with respect to the
location of discharges, the frequency
and volume of discharges, and the
constituents discharged. Similarities
and differences in the character of
CSO and SSO discharges are noted
where they occur. Comparisons of
CSOs and SSOs to other sources of
pollution have been made where
appropriate. The CSO and SSO
characterization information provided
in this chapter is important for
assessing the environmental and
human health impacts of CSOs and
SSOs.
For purposes of this Report to
Congress, the terms "wet weather" and
"dry weather" are used to distinguish
sewer overflows that are rainfall- or
snowmelt-induced from those that are
not caused by rainfall or snowmelt.
The discussion of CSOs in this report
is limited to wet weather CSOs. That
is, those CSOs that are rainfall- or
snowmelt-induced and occur at
permitted CSO outfalls. Dry weather
CSO discharges are prohibited under
the NPDES program.
SSOs can be induced by rainfall or
snowmelt when excess I/I causes the
conveyance capacity of the SSS to be
exceeded. SSOs also occur as a result
of other, non-wet weather causes such
as blockages, line breaks, vandalism,
mechanical failures, and power failure.
The terms "wet weather SSOs" and
"dry weather SSOs" are used in this
report to differentiate these two
general types of SSOs because these
events have different characteristics
and respond to different control
strategies. The discussion of SSOs
in this report, including national
estimates of volume and frequency,
does not account for wet weather or
dry weather discharges occurring after
the headworks of the treatment plant,
regardless of the level of treatment,
or backups into buildings caused
by problems in the publicly-owned
portion of the SSS.
In this chapter:
4.1 What Pollutants are in
CSOs and SSOs?
4.2 What Factors Influence
the Concentrations of the
Pollutants in CSOs and
SSOs?
4.3 What Other Point and
Nonpoint Sources Might
Discharge These Pollutants
to Waterbodies Receiving
CSOs and SSOs?
4.4 What is the Universe of
CSSs?
4.5 What are the
Characteristics of CSOs?
4.6 What is the Universe of
SSSs?
4.7 What are the
Characteristics of SSOs?
4.8 How Do the Volumes
and Pollutant Loads from
CSOs and SSOs Compare
to Those from Other
Municipal Point Sources?
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Report to Congress on the Impacts and Control ofCSOs and SSOs
4.1 What Pollutants are in CSOs
and SSOs?
T
he principal pollutants present
in CSO and SSO discharges
include:
• Microbial pathogens
• Oxygen depleting substances
(measured as BOD5)
• TSS
• Toxics
• Nutrients
• Floatables
The pollutants in CSOs and SSOs
come from a variety of sources.
Domestic wastewater contains
microbial pathogens, BOD5, TSS,
and nutrients. Wastewater from
industrial facilities, commercial
establishments, and institutions can
contribute additional pollutants such
as fats, oils, and grease (FOG), and
toxic substances including metals
and synthetic organic compounds.
Fungi do not have a major presence
in wastewater (WERF 2003b). Storm
water can also contribute pollutants to
CSSs and, in some instances, SSSs. The
concentration of pollutants in storm
water is generally more dilute than in
wastewater, but can contain significant
amounts of microbial pathogens,
BOD5, TSS, toxics (notably metals and
pesticides), nutrients, and floatables.
Pollutant concentrations in CSOs and
SSOs vary substantially, not only from
community to community and event
to event, but also within a given event.
Descriptions of the pollutants in CSOs
and SSOs are provided in the following
subsections and include comparisons
of concentration data for discharges
from different municipal sources. The
comparisons include, where available,
median pollutant concentrations
and ranges of concentrations found
in treated wastewater, untreated
wastewater, CSOs, wet weather
SSOs, dry weather SSOs, and urban
storm water. The origin and relative
availability of data on pollutant
concentrations in discharges were not
consistent for the different municipal
sources. In general, adequate data
were available to characterize treated
and untreated wastewater, CSOs, and
urban storm water. Monitoring data
to characterize actual wet and dry
weather SSO discharges, however, were
less readily available.
EPA compiled a limited dataset on
pollutant concentrations in wet
weather SSOs as part of municipal
interviews conducted for this Report
to Congress. EPA also identified a
study conducted by the Wisconsin
Department of Natural Resources
that quantified the concentration
of various constituents in wet
weather SSOs from a number of
federal and locally-sponsored studies
(WDNR 2001). The findings of
the WDNR study support the data
EPA collected on wet weather SSOs
for this Report to Congress. For
the purposes of this report, EPA
assumed that dry weather SSOs would
have the same characteristics and
pollutant concentrations as untreated
wastewater.
The descriptions of pollutants in CSOs
and SSOs include an overview of the
types of impacts typically associated
with these pollutants. The presence of
pollutants in a CSO or SSO discharge
in and of itself is not indicative of
4-2
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Chapter 4—Characterization of CSOs and SSOs
environmental or human health
impacts. The occurrence of actual
impacts depends on the concentration
of the pollutant present, the volume
and duration of the CSO or SSO
event, the location of the discharge,
the condition of the receiving water at
the time of the discharge, and, in the
case of human health, exposure. More
detailed discussions of environmental
and human health impacts of CSOs
and SSOs are presented in Chapters 5
and 6, respectively.
4.1.1 Microbial Pathogens
Microbial pathogens are
microorganisms that can cause disease
in aquatic biota and illness or even
death in humans. The three major
categories of microbial pathogens
present in CSOs and SSOs are
bacteria, viruses, and parasites. These
microbial pathogens are, for the most
part, easily transported by water. A
brief discussion of these pathogens,
including the concentrations present
in various municipal discharges, is
presented below. A more detailed
discussion of pathogens is presented in
Chapter 6 of this report.
Bacteria
The two broad categories of bacteria
associated with wastewater are
indicator bacteria and pathogenic
bacteria. Indicator bacteria are widely
used as a surrogate for microbial
pathogens in wastewater and water
quality assessments. Indicator bacteria
suggest the presence of disease-causing
organisms, but generally are not
pathogenic themselves. The principal
indicator bacteria used to assess water
quality are fecal coliform, E. coll, and
enterococcus. All three are found in
the intestines and feces of warm-
blooded animals.
Fecal coliform concentrations from
municipal sources are presented in
Table 4.1. As shown, concentrations of
fecal coliform found in CSOs and wet
weather SSOs are generally less than
the concentrations found in untreated
wastewater and dry weather SSOs,
and greater than the concentrations
reported for urban storm water.
Pathogenic bacteria are capable
of causing disease. Examples of
pathogenic bacteria associated with
untreated wastewater, CSOs, and SSOs
Municipal Sources
Untreated wastewater/dry
weather SSOs
Wet weather SSOsa
CSOsb
Urban storm water0
Treated wastewater
Number of
Samples
-
-
603
1,707
Fecal Coliform (colonies/100 ml)
Range Median
1,000,000a-
1 ,000,000,000d
-
3 - 40,000,000
1 -5,230,000
-
500,000
215,000
5,081
<200e
Table 4.1
Fecal Coliform
Concentrations in
Municipal Discharges
The presence of fecal coliform
bacteria in aquatic environments
indicates that the water has been
contaminated with fecal material
of humans or other warm-blooded
animals.
aWDNR2001
Data collected as part of municipal interviews
c Pitt etal. 2003
dNRC1996
e Limit for disinfected wastewater
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Report to Congress on the Impacts and Control ofCSOs and SSOs
include Campylobacter, Salmonella,
Shigella, Vibrio cholerae, and Yersina.
Viruses
More than 120 enteric (intestinal)
viruses may be found in sewage (NAS
1993). Concentrations of viruses
reported in wastewater vary greatly
and depend on the presence and
amount of infection in the population
served by a sewer system, season
of the year, and the methods used
for enumerating the virus counts.
Examples of viruses associated with
untreated wastewater, CSOs, and SSOs
include poliovirus, infectious hepatitis
virus, and coxsackie virus.
Parasites
The common parasites of human
health concern in untreated
wastewater are parasitic protozoa
and helminths (NAS 1993).
Parasitic protozoa include Giardia,
Cryptosporidium, and Entamoeba.
Giardia is the most common
protozoan infection in the United
States (NAS 1993). Giardia has been
detected in treated and untreated
wastewater at levels of 0.0002 to 0.011
cysts per L and 2 to 200,000 cysts
per L, respectively (Payment and
Franco 1993; Yates 1994; NAS 1998;
Rose et al. 200Ib). Cryptosporidium
has also been detected in treated
and untreated wastewater at
concentrations of 0.0002 to 0.042
oocysts per L and less than 0.3 to
13,700 oocysts per L, respectively
(Payment and Franco 1993; NAS 1998;
Rose et al. 200la; McCurin and Clancy
2004).
Several recent studies have specifically
investigated the presence of
Cryptosporidium and Giardia in CSOs.
Giardia concentrations ranging from
2 to 225 cysts per L were measured in
samples collected during two overflow
events at each of the six CSO outfalls
(EPA 2003f). A study conducted in
Pittsburgh also found Cryptosporidium
(0 to 30 oocysts per L) and Giardia
(37.5 to 1,140 cysts per L) in CSOs
(States et al. 1997). Given that both
CSOs and SSOs include untreated
wastewater, this suggests that CSOs
and SSOs are also likely to contain
significant concentrations of Giardia,
and possibly Cryptosporidium.
Helminths include roundworms,
hookworms, tapeworms, and
whipworms. These organisms are
endemic in areas lacking inadequate
access to hygiene facilities, including
toilets. Their transmission is generally
associated with untreated sewage and
sewage sludge. However, there is very
little documentation of waterborne
transmission of helminths (NAS
1993).
4.1.2 BOD5
BOD5 is widely used as a measure of
the amount of oxygen-demanding
organic matter in water or wastewater.
The organic matter in sewage is a
mix of human excreta, kitchen waste,
industrial waste, and other substances
discharged into sewer systems.
When significant amounts of BOD5
are discharged to a waterbody, the
dissolved oxygen can be depleted. This
occurs principally through the decay
of organic matter and the uptake of
oxygen by bacteria. The depletion
of dissolved oxygen in waterbodies
can be harmful or fatal to aquatic
life. Low levels of dissolved oxygen
are responsible for many of the fish
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Chapter 4—Characterization of CSOs and SSOs
1 Municipal Sources
Untreated wastewater/dry
weather SSOsa
Wet weather SSOsb
CSOsb
Urban storm water0
Treated wastewater0*
BOD5 (mg/l)
Number of Samples Range
88-451
22 6-413
501 3.9 - 696
3,110 0.4-370
Median
42
43
8.6
30
^^^E
BOD5 Concentrations in
Municipal Discharges
concentrations are the same as
those for low dissolved oxygen:
aquatic organisms become stressed,
— suffocate and die
I
a AMSA 2003a.85 facilities reported annual average BODs concentration data; each facility based its value on an
unspecified amount of monitoring
" Data collected as part of municipal interviews
c Pitt etal. 2003
Typical limit for wastewater receiving secondary treatment
kills reported and tracked by resource
agencies. BOD5 concentrations from
municipal sources are presented in
Table 4.2. As shown, the median
concentrations of BOD 5 in CSOs and
wet weather SSOs are typically five
times greater than concentrations
found in urban stormwater. Median
BOD5 concentrations in CSOs and
wet weather SSOs are typically 1.3 to
1.4 times greater than concentrations
found in treated wastewater.
4.1.3TSS
TSS is a measure of the small particles
of solid pollutants that float on the
surface of, or are suspended in, water
or wastewater. TSS in wastewater
includes a wide variety of material,
such as decaying plant and animal
matter, industrial wastes, and silt.
High concentrations of TSS can
cause problems for stream health
and aquatic life. TSS can clog fish
gills, reduce growth rates, decrease
resistance to disease, and impair
reproduction and larval development.
The deposition of solids can damage
habitat by filling spaces between
rocks that provide shelter to aquatic
organisms. TSS can accumulate in
the immediate area of CSO and
recurrent SSO discharges, creating
turbid conditions that smother the
eggs of fish and aquatic insects.
TSS concentrations from municipal
sources are presented in Table 4.3. As
shown, the median concentration of
TSS in CSOs and wet weather SSOs is
Municipal Sources
Untreated wastewater/dry
weather SSOsa
WetweatherSSOsb
CSOsb
Urban storm water0
Treated wastewaterd
Number of Samples
-
27
995
3,396
TSS (mg/l)
Range
118-487
1 0 - 348
1 - 4,420
0.5 - 4,800
Median
-
91
127
58
30
a AMSA 2003a. 121 facilities reported annual average TSS concentration data; each facility based its value on an
unspecified amount of monitoring
Data collected as part of municipal interviews
0 Pitt etal. 2003
" Typical limit for wastewater receiving secondary treatment
Table 4.3
TSS Concentrations in
Municipal Discharges
Over the long-term, the deposition
of solids in the immediate area of
CSO and SSO discharges can
damage aquatic life habitat.
ea of
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 4.4
Cadmium and Copper
Concentrations in
Municipal Discharges
For many municipalities, the largest
source of copper in wastewater is
corrosion of copper pipes (PARWQCP
1999). Other sources include
industrial discharges,copper-based
root killers,and cooling water
discharges.
Table 4.5
Lead and Zinc
Concentrations in
Municipal Discharges
Municipal wastewater treatment
facilities are reported to be the
largest point source for zinc
discharges to surface waters
(WSDOH1996).
higher than concentrations in urban
storm water.
4.1.4 Toxics
Toxics are chemicals or chemical
mixtures that, under certain
circumstances of exposure, present an
environmental or human health risk.
Toxics include metals, hydrocarbons,
and synthetic organic chemicals.
Concentrations of toxics in wastewater
can be a concern in industrialized
areas or where monitoring data
indicate potential toxicity (Moffa
1997). Storm water contributions
to CSOs in urbanized areas can also
contain significant concentrations
of hydrocarbons and metals. Metals
concentrations from municipal sources
are presented in Tables 4.4 and 4.5.
In general, environmental problems
related to toxicity fall into two
categories: chronic or long-term
exposure to toxics causing reduced
growth and reproduction, and acute
Municipal
Sources
Untreated
wastewater/dry
weather SSOsa
Wet weather
SSOs
CSOsb
Urban storm
water0
Treated
wastewaterd
Cadmium (|Jg/l)
Number of Range Median
Samples
401
2,582
465
0.1 -101
0.16-30 2
0.04-16,000 1
0.01 - 3.0 0.04
Number of
Samples
~
346
2,728
596
Copper (|Jg/l)
Range
1 .8 - 322
10-1,827
0.6-1,360
2.8-16.0
Median
~
40
16
5.2
a AMSA 2003a. 101 and 109 facilities reported annual average Cd and Cu concentrations, respectively; each facility
based its value on an unspecified amount of monitoring
"Data collected as part of municipal interviews
c Pitt etal. 2003
dWERF2000
Municipal
Sources
Untreated
wastewater/dry
weather SSOsa
Wet weather
SSOs
CSOsb
Urban storm
waterc
Treated
wastewaterd
Number of
Samples
~
-
438
2,954
21
Lead (|Jg/l)
Range Median
0.5 -250
-
5-1,013 48
0.2-1200 16
0.2 - 1 .4 0.6
Number of
Samples
~
-
442
3,016
530
Zinc(|Jg/l)
Range
9.7-1,850
-
1 0 - 3,740
0.1 - 22,500
20.0-57.5
Median
~
159
156
117
51.9
a AMSA 2003a. 106 and 109 facilities reported annual average Pb and Zn concentrations, respectively; each facility based
its value on an unspecified amount of monitoring
Data collected as part of municipal interviews
c Pitt etal. 2003
d WERF 2000
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Chapter 4—Characterization of CSOs and SSOs
or short-term exposure at higher
concentrations causing increased
mortality. Chronic effects are subtle
and difficult to identify, but can be
observed by lower productivity and
biomass (numbers of organisms),
bioaccumulation of chemicals, or
reduced biological diversity. Acute
effects can be observed as immediate
fish kills or severely reduced biologic
diversity.
4.1.5 Nutrients
Nutrients is the term generally
applied to nitrogen and phosphorus.
Untreated wastewater contains
significant amounts of nitrogen
and phosphorus from domestic and
industrial sources. CSSs also receive
nutrients contained in urban runoff
from street litter and chemical
fertilizers applied to landscaped
areas, lawns, and gardens. Nutrients
are essential to the growth of plants
and animals. Excess amounts of
nitrogen and phosphorus can cause
rapid growth of algae and nuisance
plants, as well as eutrophic conditions
that can lead to oxygen depletion.
Total phosphorus and total kjeldahl
nitrogen (a measure of ammonia
and organic nitrogen) concentrations
from municipal sources are presented
in Table 4.6. As shown for total
phosphorus, wet weather SSO
concentrations are roughly equivalent
to treated wastewater concentrations
and are approximately one-third of
untreated wastewater concentrations.
Total phosphorus concentrations
in CSO and urban stormwater are
generally less than those in wet
weather SSOs.
4.1.6 Floatables
Floatables is the term used to describe
the trash, debris, and other visible
material discharged when sewers
overflow. In SSSs, floatables generally
include sanitary products and other
wastes commonly flushed down a
toilet. In CSSs, floatables include litter
and detritus that accumulate on streets
and other paved areas that wash into
CSSs during rainfall or snowmelt
events. Floatables can have an adverse
impact on wildlife, primarily through
entanglement or ingestion. Floatables
Municipal
Sources
Untreated
wastewater/dry
weather SSOsa
Wet weather
SSOsb
CSOsc
Urban storm
waterd
Treated
wastewater3
Total Phosphorus
Number of Range
Samples
__
-
43
3,283
72
1.3-15.7
~
0.1 - 20.8
0.01 -15.4
0.07 - 6
(mg/l)
Median
5.8
2
0.7
0.27
1.65
Total Kjeldahl Nitrogen (mg/l)
Number of Range Median
Samples
59
~
373
3,199
64
11.4-61
~
0-82.1
0.05 - 66.4
0.5 - 32
33
~
3.6
1.4
3.95
Table 4.6
Nutrient Concentrations
in Municipal Discharges
Nutrient additions can cause
increased algae or aquatic weed
growth that, in turn, can deplete
dissolved oxygen, reduce biologic
diversity, worsen aesthetics,and
impair use for water supply (Moffa
1997).
a AMSA2003a. 59 facilities reported annual average total PandTKN concentrations; each facility based its value on an
unspecified amount of monitoring
bWDNR2001
c Data collected as part of municipal interviews
d Pitt etal. 2003
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Report to Congress on the Impacts and Control ofCSOs and SSOs
can also contribute to aesthetic impacts
in recreation areas.
An extensive monitoring program
conducted in New York City suggests
that more than 90 percent of
floatables in the city's CSOs originate
as street litter (NYCDEP 1997). The
monitoring program specifically found
that street trash, including plastics,
polystyrene, and paper, accounted
for approximately 93 percent of the
floatables discharged. Personal hygiene
items and medical materials accounted
for approximately one percent of all
floatables discharged into New York
Harbor through CSOs. The remaining
six percent of floatable items included
glass, metal, wood, and cloth.
4.2 What Factors Influence
the Concentrations of the
Pollutants in CSOs and
SSOs?
The pollutant concentrations
associated with CSO and SSO
discharges are highly variable.
Pollutant concentrations vary not
only from site to site and event to
event, but also within a given overflow
event. Brief descriptions of some of
the factors that influence pollutant
concentrations in CSOs and SSOs are
described in the following subsections.
4.2.1 Factors Influencing Pollutant
Concentrations in CSOs
The relative amounts of domestic,
commercial, and industrial wastewater,
and urban storm water carried by a
CSS during specific wet weather events
are the primary driver of pollutant
concentrations in CSOs. Other factors
that contribute to the variability
include:
• Elapsed time since the wet weather
event began, with higher pollutant
concentrations expected during
the early stages of a CSO event
(often termed the "first flush");
• Time between the current
and most recent wet weather
events, with higher pollutant
concentrations expected in CSOs
occurring after lengthier dry
periods; and
• Intensity and duration of the wet
weather event.
The sudden rush of flow into a CSS
brought on by rainfall, or in some
instances, snowmelt, can create a
first flush effect. The first flush effect
occurs when pollutants washed from
city streets and parking lots combine
with pollutants re-suspended from
settled deposits within the CSS.
This combination can produce
peak pollutant concentrations at
the beginning of the CSO event,
particularly if rainfall is intense. First
flush effects are typically observed
during the first 30 to 60 minutes of
a CSO discharge (Moffa 1997). They
are generally more pronounced after
an extended dry period and in sewer
systems with low gradients (slope).
Many CSO control programs have
been designed specifically to capture
the first flush.
4.2.2 Factors Influencing Pollutant
Concentrations in SSOs
Wastewater flows generated by
domestic, commercial, and industrial
sources fluctuate on diurnal, weekend/
weekday, and seasonal cycles. Periods
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Chapter 4—Characterization of CSOs and SSOs
of low and high flows are associated
with water demand and use. SSSs
carry varying amounts of I/I during
wet weather periods, when the ground
is saturated, and when the water table
is elevated. The amount of I/I entering
an SSS is influenced by:
• Age and condition of SSS
components
• Local use of SSS for roof and
foundation drainage
• Location of sewer pipes relative to
the water table
• Characteristics of recent rainfall
events
• Soil type and antecedent soil
moisture conditions
The amount of I/I, in turn, influences
the concentration of pollutants in SSO
discharges.
Dry weather SSOs consist mainly of
domestic, commercial, and industrial
wastewater, with limited amounts
of I/I. Therefore, the pollutant
concentrations in dry weather SSOs
are most heavily influenced by the
relative contribution from domestic,
commercial, and industrial customers
to the total flow.
4.3 What Other Point and
Nonpoint Sources Might
Discharge These Pollutants
to Waterbodies Receiving
CSOs and SSOs?
CSOs and SSOs contribute
to pollutant loadings where
discharges occur. Waterbodies
also receive pollutants of the types
found in CSOs and SSOs from other
point and nonpoint sources including:
• Wastewater treatment facilities
• Decentralized wastewater
treatment systems
• Industrial point sources
• Urban storm water
• Agriculture
• Domestic animals and wildlife
• Commercial and recreational
vessels
The contribution of pollutant loads
from CSOs and SSOs relative to
other point and nonpoint sources
varies widely depending on the
characteristics of the waterbody and
the volume, frequency, and duration
of CSO and SSO events. Each of these
sources is discussed briefly below.
In 1999, the Augusta Sanitary District completed the first phase of a $40-million
five-phase CSO Long Term Control Plan as part of an Administrative Order (AO).
Phase One involved a $12.2-million upgrade of the wastewater treatment plant to
increase the treatment capacity and to better treat excess wet weather flows from
the CSS. Prior to the upgrade,excess wet weather flows received minimal treatment
(sometimes bypassing primary and secondary treatment processes entirely) and
were not disinfected prior to discharge. Since completion of the treatment plant
upgrade, the District bypasses secondary treatment processes only during wet
weather events, and has the capacity to provide primary treatment, chlorination,
and dechlorination to the bypassed flows. Bypassing frequency has decreased by
70 percent.
CSO-related Bypass at
Wastewater Treatment Facility:
Augusta, ME
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Wet Weather Bypass at
Wastewater Treatment Facility
Serving SSS:
Jefferson County, AL
The Village Creek Wastewater Treatment Plant in Jefferson County, Alabama,
routinely experienced peak wet weather flows greater than 10 times its annual
average flow of 40 mgd. Due to extreme peak wet weather flows in the system,
untreated wastewater was frequently diverted from the Village Creek plant and
discharged without treatment. Between 1997 and 2001, excess wastewater flow
was diverted and discharged an average of 41 times per year. Under a Consent
Decree issued in 1996, Jefferson Country initiated corrective actions to address
diversions of untreated wastewater from the Village Creek facility, as well as other
problems within the system.The total cost for the improvements are estimated to
approach $2.5 billion.
4.3.1 Wastewater Treatment
Facilities
Wastewater treatment facilities
are designed to receive domestic,
commercial, and industrial wastewater,
and to treat it to the level specified in
an NPDES permit. Permits typically
define effluent concentration limits
for BOD5 and TSS, and for indicator
bacteria (typically fecal coliform, E.
coli, or enterococci) when disinfection
is required. Wastewater treatment
facilities that discharge to impaired
or sensitive waters may have more
stringent effluent limits for BOD5,
TSS, or additional parameters (e.g.,
additional reduction of nutrients and
metals).
Wastewater treatment facilities in
the United States are estimated to
contribute to the impairment of
four percent of the nation's assessed
rivers and streams; five percent of
the nation's assessed lakes, ponds,
and reservoirs; and 19 percent of
assessed estuaries (EPA 2002c). The
concentrations of fecal coliform,
BOD5, TSS, metals, and nutrients
in treated and untreated wastewater
can be compared using the tables in
Section 4.1 of this report.
Untreated and Partially Treated
Discharges from Wastewater
Treatment Facilities
In CSSs and to a lesser degree in
SSSs, flows to wastewater treatment
facilities increase during periods of
wet weather. Significant increases in
influent flow caused by wet weather
conditions (e.g., due to I/I into the
sewer system) can create operational
challenges for treatment facilities
and can adversely affect treatment
efficiency, reliability, and control
of treatment processes. Excess wet
weather flows can result in discharges
of untreated or partially treated
wastewater at the treatment facility.
Treatment plants are sometimes
designed to route peak wet weather
flows that exceed capacity around
secondary treatment units and then
blend them with treated wastewater to
meet permit limits. Volumes associated
with wet weather discharges can be
substantial.
Treatment facilities serving CSSs
may be allowed to discharge partially
treated wastewater (e.g., wastewater
having received primary treatment
and disinfection, if necessary) during
periods of wet weather, according to
4-10
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Chapter 4—Characterization of CSOs and SSOs
the terms of their permit. Untreated
wet weather discharges at treatment
facilities serving CSSs are not
permitted and are required to be
reported to the NPDES authority
within 24 hours of their occurrence.
With rare exception, treatment
facilities serving SSSs are only
permitted to discharge wastewater that
has received appropriate treatment.
Discharges of untreated wastewater
at treatment facilities serving SSSs are
required to be reported to the NPDES
authority within 24 hours of their
occurrence.
4.3.2 Decentralized Wastewater
Treatment Systems
Decentralized wastewater treatment
systems are on-site or clustered
wastewater systems used to treat and
dispose of relatively small volumes
of wastewater, generally from private
residences and businesses that are
located in close proximity to each
other. These systems serve individual
residences as well as trailer parks,
recreational vehicle parks, and
campgrounds. They are commonly
referred to as septic systems, private
sewage systems, or individual
sewage systems. Some decentralized
systems are designed to have a
surface discharge. Approximately
25 percent of the total population
of the United States is served by
decentralized wastewater treatment
systems, and about 33 percent of
new residential construction employs
this type of treatment (EPA 2003g).
The 2001 American Housing Survey
for the United States reported
that approximately 6 percent of
decentralized wastewater treatment
systems fail annually. Depending
on assumptions about persons per
household and water use, these failures
may result in improper treatment
of 180 to 396 million gallons of
wastewater daily, or 66 to 144 billion
gallons discharged annually. Failing
decentralized wastewater treatment
systems can contribute to pathogen
and nutrient contamination of surface
water and groundwater (Bowers 2001).
4.3.3 Industrial Point Sources
Industrial point sources include non-
municipal industrial and commercial
facilities that treat and discharge
wastewater, with attendant pollutants,
directly to receiving waters. Unlike
municipal wastewater treatment
facilities, the types of raw materials,
production processes, and treatment
technologies utilized by industrial
and commercial facilities vary
widely. Consequently, the pollutants
discharged by industrial point sources
vary considerably and are dependent
on specific facility characteristics (EPA
1996b). In addition to wastewater,
industrial point sources can also
collect and discharge storm water
runoff generated at their facility.
Industrial point sources are regulated
under the NPDES point source
and storm water programs. Many
discharges are governed by industry-
specific effluent guidelines. Industrial
point sources can be a major source
of pollutants, particularly nutrients
and toxics, in waters receiving the
discharges.
4.3.4 Urban Storm Water
Urban storm water runoff occurs
when rainfall does not infiltrate into
the ground or evaporate. Urban storm
water runoff flows onto adjacent
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Report to Congress on the Impacts and Control ofCSOs and SSOs
land, directly into a waterbody, or
is collected and routed through a
separate storm sewer system. Urban
storm water runoff is principally
generated from impervious surfaces
such as city streets and sidewalks,
parking lots, and rooftops. In
general, the degree of urbanization
increases the variety and amount of
pollutants carried by storm water
runoff. Although concentrations of
specific pollutants in urban storm
water runoff vary widely, the most
common pollutants include microbial
pathogens from pet and wildlife
wastes; TSS; metals, oil, grease, and
hydrocarbons from motor vehicles;
and nutrients, pesticides, and
fertilizers from lawns and gardens
(EPA2003h).
Urban storm water discharges are a
leading cause of impairment of the
nation's surface waters (EPA 2002c).
Storm water is estimated to contribute
to the impairment of 5 percent of
assessed river miles nationwide, 8
percent of assessed lake acres, and 16
percent of assessed estuarine square
miles (EPA 2002). EPA has estimated
that approximately 27.6 billion gallons
of storm water runoff are generated
daily from urbanized areas nationwide
(EPA2002c).
4.3.5 Agriculture
Agriculture is a major source of
pollution in the United States and
the leading source of impairment
in assessed rivers and streams, as
well as in assessed lakes, ponds, and
reservoirs (EPA 2002c). Agricultural
sources that contribute pollutant
loads to waterbodies include row
crops, pastures, feed lots, and holding
pens. Agricultural practices that add
pollution include over-application
of manure, other fertilizers, and
pesticides; tillage practices that leave
the earth exposed to erosion; and
pasture and range practices that
provide livestock with direct access
to waterways. These practices add
microbial pathogens, BOD 5, TSS,
toxics, and nutrients to runoff from
agricultural areas. More than 150
microbial pathogens found in livestock
manure are associated with health
risks to humans. This includes the
microbial pathogens that account
for more than 90 percent of food
and waterborne diseases in humans
(EPA 2003i). These pathogens are
Campylobacter, Salmonella (non-
typhoid), Listeria monoctyogenes,
pathogenic E. coll, Cryptosporidium,
and Giardia.
4.3.6 Domestic Animals and
Wildlife
Although livestock are believed to be
the greatest contributor of animal
waste to receiving waters, loads from
pets, wild birds, and other mammals
can be significant (EPA 200Id). This
is particularly true in urban areas
where there are no livestock, but pets
and wildlife are common. In addition,
the feces of waterfowl (e.g., geese
and ducks) can contribute significant
nutrient loads to waterbodies (Manny
et al. 1994).
Animal waste associated with pets,
wild birds, and small mammals can
present significant risk to humans.
Between 15 and 50 percent of pets and
10 percent of mice and rats may be
infected with Salmonella (NAS 1993).
In addition, many wildlife species are
reservoirs of microorganisms that can
be pathogenic to humans. Beaver and
4-12
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Chapter 4—Characterization of CSOs and SSOs
deer are large contributors of Giardia
and Cryptosporidium, respectively
(EPA 200Id). Waterfowl such as geese,
ducks, and heron can also contaminate
surface waters with microbial
pathogens (Graczyk et al. 1998).
Bacteria source-tracking can be
employed to establish the relative
contribution of human and non-
human sources to levels of indicator
bacteria measured in a given
waterbody. For example, watershed
studies in the Seattle, Washington
area found that nearly 20 percent of
bacteria in receiving water samples
were traceable to dogs (EPA 200Id). A
study of Four Mile Run in Northern
Virginia found that waterfowl
accounted for 37 percent, humans
and dogs together accounted for 26
percent, and raccoons accounted for
15 percent of the bacteria. Deer and
rats contributed smaller percentages
(NVPDC2000).
4.3.7 Commercial and Recreational
Vessels
Improper disposal of sewage by
commercial and recreational vessels
can spread disease, contaminate
shellfish beds, and lower oxygen levels
in receiving waters (CFWS 2003).
Improper disposal is also a problem
in marinas and harbors, despite
the prohibition on the discharge of
untreated sewage in the Great Lakes,
in all navigable rivers, and within
three miles of the U.S. coastline.
Improper disposal of sewage occurs
largely as a result of inadequate
facilities on-board vessels and at
docks, and a lack of education about
safe handling and disposal of sewage.
Boaters often illegally dump or dispose
sewage improperly in marina toilets,
overloading them (Baasel-Tillis
1998). Impacts due to pollution from
commercial and recreational vessels
are highly localized.
4.4 What is the Universe of
CSSs?
Most CSSs are located in
the Northeast and Great
Lakes regions. Thirty-
two states (including the District of
Columbia) have permitted CSSs in
their jurisdiction. As of July 2004,
these 32 states had issued 828 active
CSO permits to 746 communities.
These permits regulate 9,348 CSO
discharge points. The distribution
of CSO permits and CSO outfalls in
each state are shown in Figures 4.1
and 4.2, respectively. About 46 million
people are served by CSSs, which
include an estimated 140,000 miles of
municipally-owned sewers.
CSO permits have been issued to the
owners and operators of two types of
CSSs:
• CSSs owned and operated by
the same entity that owns and
operates the receiving POTW; and
• CSSs that convey flows to a POTW
owned and operated by a separate
entity under a different permit.
Communities that operate and
maintain a sewer system but send
wastewater flows to a treatment plant
owned and operated by another entity
are referred to as "satellite systems."
The 828 active CSO permits include
616 combined systems with POTWs,
176 satellite systems, and 36 systems
that EPA has been unable to classify
due to insufficient data.
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Report to Congress on the Impacts and Control of CSOs and SSOs
Figure 4.1
Distribution of CSO Permits by Region and by State
More than half of the nation's 828 active CSO permits are held by communities in
four states: Illinois, Indiana,Ohio,and Pennsylvania.
Total Permits: 828
108 107
11
AK OR WA
SD
46
68
IL IN Ml MN OH Wl
Region 10 Region 8
Region 5
NJ NY
Region 2
39
11 :ih;;
CT MA ME NH Rl VT
Region 1
Region 9
Region 7
Region 4
56
11- 3
DC DE MD PA VA WV
Region 3
4-14
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Chapter 4—Characterization of CSOs and SSOs
Figure 4.2
Distribution of CSO Outfalls by Region and by State
Similar to the distribution of CSO perm its, CSO outfalls are also concentrated in the
Northeast and Great Lakes regions.
1,378
Total Outfalls: 9,348
1,032
876
T-
224
86 1
!•! 1
2
262
h
255
I 1
278
207
1 40 76 62
1 . • •
AK OR WA SD IL IN Ml MN OH Wl NJ NY CT MA ME NH Rl VT
Region 10 Regions Regions Region 2 Region 1
Region 9
IA KS MOaNE
Region 7
GA KY IN
Region 4
DC DE MD PA VA WV
Region 3
aSince the 2001 Report to Congress—Implementation and Enforcement of the Combined Sewer Overflow Control Policy, the Missouri Department
of Natural Resources has been working with its CSO communities to confirm the number of CSO outfalls for each NPDES permit.The significant
increase in the number of CSO outfalls in Missouri is a result of this effort.
4-15
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Report to Congress on the Impacts and Control ofCSOs and SSOs
NPDES permittees are classified by
regulatory authorities as "major"
or "minor" dischargers. Facilities
are classified as "major" when the
wastewater treatment plant is designed
to discharge more than 1 mgd.
Facilities with flows less than 1 mgd
may be classified as "major" when the
NPDES authority determines that
a specific permit needs a stronger
regulatory focus. Classification as
"major" is used to guide permitting,
compliance, and enforcement activities
to ensure that larger sources of
pollutants are given priority. Major
facilities are typically inspected
annually and must report monthly
effluent concentrations and loadings.
Based on information available in
EPA's PCS for the 828 active CSO
permits, EPA found that 57 percent
were classified as major facilities.
Facilities classified as "minor" usually
have design flows less than 1 mgd.
The CSO Control Policy established
a population threshold of 75,000 to
define small jurisdictions that may
be held to less rigorous requirements
in developing an LTCP for CSO
control. EPA does not have population
data by permit for CSSs. EPA has
previously estimated that average daily
wastewater flows are approximately
100 gallons per capita per day (EPA
1985). As a surrogate, plants treating
7.5 mgd (75,000 x 100 gallons per
capita per day) are used to define the
upper limit of a small jurisdiction.
EPA obtained flow data for 398 of
the 616 permits for CSSs that include
a POTW. As shown in Figure 4.3, 73
percent of CSO permits (with available
flow data) are for POTWs with design
flows less than 7.5 mgd, and therefore
an estimated service population of less
than 75,000.
4.5 What are the
Characteristics of CSOs?
An accurate characterization
of the frequency, volume, and
location of CSO discharges,
coupled with information on the
pollutants present in the discharges, is
Figure 4.3
Distribution of POTW
Facility Sizes Serving CSSs
'OTWs serving CSSs are designed to
treat flows ranging from 0.1 mgd to
1,600 mgd, but most treat less than
.5 mgd.
7
Distribution of POTW Treatment Capacities
mgd
30%
13%
24%
Small
Jurisdictions
73%
9%
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Chapter 4—Characterization of CSOs and SSOs
needed to fully evaluate the potential
for environmental and human health
impacts from CSOs. This section
describes the process EPA used to
characterize CSO discharges at the
national level.
4.5.1 Volume of CSOs
EPA applied the previously developed
GPRACSO model to estimate
the volume and pollutant loads
attributable to CSOs nationwide. A
summary of the GPRACSO model and
how it was used to derive the national
estimates presented in this report is
provided in Appendix E.
The GPRACSO model was applied to
estimate the CSO volume associated
with three planning-level scenarios.
Corresponding BOD5 loads associated
with the CSO volumes were also
estimated. The three scenarios
modeled are:
• Baseline scenario (1992)
representing CSO volumes and
pollutant loads prior to issuance
of the CSO Control Policy.
• Current implementation scenario
(2002) representing estimates
of CSO volumes and pollutant
loads with CSO controls that are
currently in place.
• Full CSO Control Policy
implementation scenario
representing future CSO volume
and pollutant loads assuming
full implementation of the CSO
Control Policy (e.g., four to six
untreated overflows per year).
The three scenarios are compared in
terms of CSO volume and pollutant
load reduction in Table 4.7. National
estimates of the annual volume of
combined wastewater generated and
treated are added for context. The
volume of combined wastewater
generated represents the volume of
domestic, commercial, and industrial
wastewater and storm water runoff
that enters CSSs across the nation
during wet weather periods under
annual average conditions. The
estimate of combined wastewater
treated represents the amount of
combined wastewater that receives the
minimum treatment specified under
Scenario
Baseline, prior to
CSO Control Policy
Annual Volume
(billion gallons/yr)
Combined
Wastewater
Generated
4,250
Combined
Wastewater
Treated
3,180
Untreated
CSO
Discharged
1,070
Annual Load
(million pounds/yr)
BOD5 from Untreated CSO
Discharges
445
Current level of CSO
control
4,230
3,380
850
Full CSO
Control Policy
implementation
4,230a
4,070a
160
367
159
a Assumes that the areas and populations served by CSSs will remain relatively constant at current levels through full
implementation of the CSO Control Policy.
Volume Reduction
Estimates Based on
Implementation of CSO
Control Policy
EPA's GPRACSO model was used to
evaluate the potential reduction in
discharges of untreated CSO and
the attendant 6005 loads based
on current and future expected
implementation of CSO controls.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
the CSO Control Policy (primary
clarification or equivalent and
disinfection, as necessary). The volume
of combined wastewater treated under
the three scenarios is not constant,
as each reflects a different control
condition.
EPA took a conservative approach
in using the GPRACSO model to
estimate reductions in CSO volumes
and BOD5 loads. Only structural CSO
controls, such as expanded capacity at
a wastewater treatment facility, were
considered. Non-structural controls,
such as enhanced pretreatment
requirements, inflow reduction,
and pollution prevention, were not
simulated with the GPRACSO model.
The fact that sewer separation can
lead to increased storm water volumes
and loads was not factored into this
analysis.
The GPRACSO model estimates
that prior to issuance of the CSO
Control Policy (baseline scenario)
approximately 1,070 billion gallons
of untreated CSO and 445 million
pounds of BOD5 were discharged
annually from CSSs. Under the
current implementation scenario,
the GPRACSO model estimates that
approximately 850 billion gallons
of untreated combined sewage and
367 million pounds of BOD5 are
discharged from CSSs annually. The
GPRACSO model estimates that the
national CSO volume and associated
BOD5 loads have decreased by 21
percent and 18 percent, respectively,
since issuance of the CSO Control
Policy.
The full CSO Control Policy
implementation scenario assumes
that all CSO communities have, at a
minimum, implemented the controls
necessary to reduce the frequency of
CSO events to an average of four to
six untreated CSO events per year. The
actual level of control needed to meet
water quality standards may require
measures beyond those needed for an
average of four to six events per year.
When full implementation is achieved
under this scenario, the GPRACSO
model predicts that approximately
160 billion gallons of untreated CSO
and 159 million pounds of BOD5
would be discharged annually from
CSSs. Reaching a full implementation
of CSO control will require
communities with CSSs to provide
the equivalent of primary clarification
and disinfection, as necessary, to
an estimated additional 690 billion
gallons of currently untreated CSO
discharges.
4.5.2 Frequency of CSOs
In the CSO Control Policy, a "CSO
event" is defined as a discharge from
one or more CSO outfalls in response
to a single wet weather event. The
frequency of CSO events in a given
community can range from zero
events to 80 or more per year. The
frequency of CSO events in a given
community can also vary considerably
from year to year depending on
weather conditions. The CSO Control
Policy specifies that the evaluation
of CSO control alternatives and
development of LTCPs should be
on a system-wide, annual average
basis. Annual average conditions are
typically established by performing a
statistical analysis on local, long-term
precipitation records that consider the
number of precipitation events per
year, maximum rainfall intensity, and
average storm duration.
4-18
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Chapter 4—Characterization of CSOs and SSOs
In addition to estimating national
CSO volumes and pollutant loads,
the GPRACSO model was used to
estimate the frequency of CSO events.
Under the baseline scenario, prior to
issuance of the CSO Control Policy,
the GPRACSO model estimates that
there were approximately 60,000 CSO
events per year nationwide. Under
the current implementation scenario
with the current level of CSO control,
the GPRACSO model estimates
there are 43,000 CSO events per year
nationwide, a reduction of 28 percent
since the issuance of the CSO Control
Policy.
4.5.3 Location of CSOs
A key EPA initiative undertaken
as part of this Report to Congress
was to update, verify, and digitally
georeference the inventory of
CSO outfalls documented as part
of EPAs 2001 Report to Congress-
Implementation and Enforcement of
the CSO Control Policy. This effort
resulted in establishing latitude and
longitude coordinates for more than
90 percent of CSO outfalls.
With this new information, EPA
was able to associate those CSO
outfalls with latitude and longitude
coordinates with specific waterbody
segments (reaches) identified in the
NHD. The NHD is a comprehensive
set of digital spatial data of surface
water features that enables analysis
of water-related data in upstream
and downstream order. Associating
CSO outfall locations with the NHD-
indexed assessed waters allowed
analysis of the types of waterbodies
receiving CSO discharges. Through
this analysis, EPA found:
• 75 percent of CSOs discharge to
rivers, streams, or creeks;
• 10 percent of CSOs discharge to
oceans, bays, or estuaries;
• 8 percent of CSOs discharge to
waters that are unclassified or
unidentified in the NHD;
• 5 percent of CSOs discharge to
other types of waters (unnamed
tributaries, canals, etc.); and
• 2 percent of CSOs discharge to
ponds, lakes, or reservoirs.
Further, associating CSO outfall
locations with the NHD-indexed
assessed waters allowed comparison
with impairments reported by states
in the 303(d) program (waters not
meeting water quality standards or not
supporting their designated uses), and
the location of protected resources
and sensitive areas. These analyses are
discussed in more detail in Section
5.3 of this report. Additional detail on
the CSO analysis using the NHD is
presented in Appendix F.
4.6 What is the Universe of
SSSs?
EPAs 2000 CWNS reported
15,582 municipal SSSs with
wastewater treatment facilities
across the nation (EPA 2003b). EPA
has also identified an additional 4,846
satellite SSSs that collect and transport
wastewater to regional treatment
facilities (EPA 2003b). The number
of SSSs with wastewater treatment
facilities and the number of satellite
systems are shown for each state in
Figures 4.4 and 4.5, respectively.
4-19
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure 4.4
Distribution of SSSs with Wastewater Treatment Facilities by EPA
Region and by State
SSSs are located in all 50 states. EPA's 2000 CWNS reported 15,582 municipal SSSs with
wastewater treatment facilities across the nation.
100
200 300
400 500
600
700 800
Region 1
1500
1,363
^^
Region 10
4-20
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Chapter 4—Characterization of CSOs and SSOs
Figure 4.5
Distribution of Satellite SSSs by Region and by State
EPA identified 4,846 satellite SSSs that collect and transport flows to regional wastewater
treatment facilities; such systems exist in all states, with the exception of Hawaii.
Region 1
Region 2
Region 3
Region 4
Region 5
100
200
300
400
500
600
700
800
CT
MA
ME
NH
Rl
VT
NJ
NY
DE
MD
PA
VA
WV
AL
FL
GA
KY
MS
NC
SC
TN
IL
IN
ME
Ml
OH
Wl
4-21
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure 4.6
States Providing
Electronic Data on SSO
Discharges
EPA identified 25 states in which
the NPDES authority is using an
electronic data system to track the
volume, frequency, location, and
cause of SSO discharges within its
jurisdiction. Data from these states
were used to develop national
estimates of SSO frequency and
volume.
EPA estimates that 164 million people
are served by municipal SSSs. EPA
estimates that SSSs contain 584,000
miles of municipally-owned sewer
pipes and that approximately 500,000
miles of privately-owned pipes deliver
wastewater into SSSs (EPA 2003b).
As described in Section 4.4, NPDES
permittees are commonly classified
by NPDES authorities as "major"
or "minor" dischargers. Based on
information available in PCS for
permits issued to SSSs with wastewater
treatment facilities, EPA found that
80 percent were classified as minor
facilities, with average daily discharges
less than 1 mgd.
4.7 What are the
Characteristics of SSOs?
An accurate characterization
of the frequency, volume, and
location of SSO discharges,
coupled with information on the
pollutants present in the discharges, is
needed to fully evaluate the potential
for environmental and human health
impacts from SSOs. Currently, there
are no federal systems in place to
compile data on the frequency,
volume, and location of SSO
discharges. This section describes the
processes EPA used to characterize
SSOs.
4-22
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Chapter 4—Characterization of CSOs and SSOs
4.7.1 SSO Data Management
System
For the purposes of this report, EPA
identified 25 states where the NPDES
authority is using an electronic data
system to track the volume, frequency,
location, and cause of SSO discharges
within its jurisdiction. As shown in
Figure 4.6, these 25 states are spread
across the nation.
EPA collected the individual state
datasets and compiled them in a single
SSO data management system. In its
collection of SSO data from the states,
EPA found that the definition of an
"SSO event" varied. For example,
some states include incidents such as
secondary treatment bypasses which
exceed NPDES permit limits by more
than 50 percent at the main outfall,
and spills from septic haulers as SSO
events in their data systems. EPA also
found that backups into buildings
caused by problems in the publicly-
owned portion of an SSS are not
tracked by states.
SSOs are untreated or partially treated
releases from an SSS. The discussion
of SSOs in this report does not
include discharges occurring after the
headworks of the treatment plant,
regardless of the level of treatment;
or backups into buildings caused
by problems in the publicly-owned
portion of an SSS. Datasets for each
state were screened using these
qualifiers. SSO events that did not
meet the above criteria were omitted
from the SSO data management
system and from the analyses of
SSO frequency, volume, and cause
presented later in this chapter.
Additional information on the data
management system is provided in
Appendix G of this report.
4.7.2Statistical Technique Used
to Estimate Annual National
SSO Frequency and Volume
National estimates of SSO frequency
and volume were generated using
reported data on 33,213 SSO events
in 25 states that occurred in calendar
years 2001, 2002, and 2003, combined
with basic information describing
the sewered universe in each state
from the 2000 CWNS. This basic state
information included:
• Total number of sewer systems
by state (combined and separate
sanitary);
• Number of SSSs by state; and
• Population served by SSSs by state.
To account for the uncertainty in the
data reported by states, two separate
scenarios were evaluated:
• The first scenario assumed that
SSO events tracked in the state's
data system include all of the SSO
events that occurred statewide
during the reporting period.
• The second scenario assumed that
SSO events tracked in the state's
data system include SSO events
from only those communities that
chose to report and are therefore
a fraction of SSO events that
occurred statewide during the
reporting period.
Regression analyses demonstrated that
the frequency of SSO events in a state
is correlated both to the total number
of SSSs as well as to the population
served, although neither parameter
4-23
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure 4.7
Total Number of SSO
Events Reported by
Individual Communities,
January 1,2001 -
December 31,2003
Nearly 70 percent of the
communities in the 25 states
reported between one and four
SSO events during the three-year
reporting period.
is a perfect predictor. To account for
the uncertainty as to which provides
the better national estimate of SSO
frequency, two additional sub-
scenarios were analyzed:
• Estimating SSO event frequency
for non-reporting states based on
total number of SSSs in each state;
and
• Estimating SSO event frequency
for non-reporting states based
on the total population served by
SSSs in each state.
National estimates of SSO volume
were generated using the following
five-step procedure:
1. Tabulate the total number of
events and SSO volume for each
of the reporting states.
2. Estimate the total number of SSO
events per year for each non-
reporting state based on a) the
number of SSSs in the state, and
b) the population served by SSSs
in the state.
3. Divide the total number of events
in each non-reporting state into
different categories describing the
cause of the SSO event, accounting
for observed regional differences
from the 25 reporting states.
4. Calculate SSO volume for each
cause category in each non-
reporting state, accounting for
observed regional differences.
5. Calculate national estimates
by summing the total number
of events by state and the total
volume across all states.
A detailed explanation of the statistical
techniques applied to the SSO data
provided by the 25 states is presented
in Appendix G.
4.7.3 Frequency of SSOs
Between January 1, 2001, and
December 31, 2003, 33,213 SSO
events were reported by individual
communities in the 25 states.
During this three-year period, 2,663
communities reported one or more
SSO discharges. The number of
SSO discharges reported by each
community is presented in Figure
4.7. As shown, most of the 2,663
Percent Reported
VI
o
I/I
•a
Si
I
0)
ce
"o
0)
01
E
flj
OC
1
2-4
5-7
8-10
11-20
21-30
31-40
41-50
51-75
76-100
>100
^H
7%
^H 3%
H 2%
• 1%
H 2%
•
• 2%
4-24
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Chapter 4—Characterization of CSOs and SSOs
communities reported between one
and four SSO events during the
three-year reporting period. One
community reported more than 1,300
SSOs over the three years.
Using the statistical techniques
described previously, and in Appendix
G, SSO frequency information in
the SSO data management system
was extrapolated into a national
estimate. This analysis suggests that
between 23,000 and 75,000 SSO
events per year occur in the United
States. EPA evaluated the SSO
frequency information in the SSO
data management system for regional
trends and found only marginal
regional effects for overall event
frequency. Therefore, EPA did not
make adjustments to the estimated
number of SSO events in non-
reporting states based on geographic
location.
4.7.4 Volume of SSOs
Estimated SSO volumes were reported
and available for 28,708 (86 percent)
of the 33,213 events included in
the SSO data management system.
Between January 1, 2001, and
December 31,2003, a total of 2.7
billion gallons of SSO was reported
discharged in the 25 states. The
reported volume for individual SSO
events ranged from one gallon to 88
million gallons. The distribution of
reported SSO volumes for these events
is presented in Figure 4.8. As shown:
• More than half of the reported
SSOs were less than 1,000 gallons;
• More than 80 percent of the SSOs
were less than 10,000 gallons; and
• Approximately 2 percent of the
SSOs were greater than 1 million
gallons.
Further, the 1,000 largest SSO events
(3 percent of reported events)
accounted for almost 90 percent of the
total SSO volume reported.
01
o
in
in
1 -100
gallons
101 -1,000
gallons
1,001-10,000
gallons
10,001 -100,000
gallons
100,001 -1,000,000
gallons
1,000,001 -10,000,000
gallons
> 10,000,000
gallons
Distribution of SSO Volume Reported
17%
29%
12%
5%
Figure 4.8
Distribution of SSO
Volume Reported Per
36% Event
Estimated SSO volumes were
available for 86 percent of events in
the SSO data management system.
The reported volumes for individual
SSO events ranged from one gallon
to 88 million gallons.
1%
4-25
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Using the statistical techniques
described in Appendix G, data on the
volume discharged during individual
SSO events were extrapolated into
a national estimate of the annual
volume of SSO discharged. This
analysis suggests that the total SSO
volume discharged annually is
between three and 10 billion gallons.
In an unpublished EPA report
supporting a draft rulemaking on
SSOs, EPA previously estimated that
the national volume of SSO discharges
caused by wet weather totaled 311
billion gallons per year. That estimate
was derived from a model designed
to predict the relationship between
the frequency of wet weather SSO
events and the required national
investment in SSO control measures.
The model was based on variables
such as sewer system capacity, acreage
served by SSSs, and the percentage
of rainfall that became I/I. Values
assigned to each of these variables
were based on very little empirical
data, and the output of the model was
not verified. EPA has a much higher
degree of confidence in the national
SSO volume estimates presented in
this Report to Congress because the
new estimates are based on a much
larger empirical data set and rely on a
simplified approach for extrapolating
to a national estimate.
4.7.5 Location of SSOs
SSOs can occur at any location in the
SSS, including: manholes, cracks and
other defects in sewer lines, emergency
relief outlets, and elsewhere. Reports
of SSO events often include street
addresses where the spill occurred.
Because SSO events can occur at so
many locations, gathering latitude and
longitude for SSOs at a national level
is impractical. Rather, it is more useful
to look at the cause of the events,
which is often linked to the type of
location where it occurs. EPA grouped
the reported SSO events into five
broad cause categories:
• Blockages
• Wet weather and I/I
• Power and mechanical failures
• Line breaks
• Miscellaneous (e.g., vandalism,
contractor error)
In general, SSOs attributed to
wet weather and I/I are caused by
insufficient sewer system capacity,
while the other types of spills are
attributable to sewer system operation
and maintenance.
Cause information was available for
77 percent of the SSO events included
in the SSO data management system.
As shown in Figure 4.9, 48 percent
of all SSO events with a known cause
were the result of the complete or
partial blockage of a sewer line, and
26 percent of SSO events were caused
by wet weather and I/I. In general, the
communities reporting large numbers
of SSO events have programs that
place a strong emphasis on tracking.
As a result, EPA believes that these
communities are likely to identify
additional low-volume SSO events
(e.g., SSOs resulting from blockages)
that have the potential to go unnoticed
or unreported in other jurisdictions.
EPA evaluated the reported causes
of SSO events in the SSO data
management system for regional
trends and found significant
4-26
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Chapter 4—Characterization of CSOs and SSOs
Causes of SSO Events
Percent
v ^y7 Blockages 48%
\ ^
V
/ v
r T
Total
Wet weather and I/I
Mechanical or power failures
Line breaks
Miscellaneous
26%
11%
10%
5%
100%
Figure 4.9
Most Common Reported
Causes of SSO Events
Nearly 50 percent of all SSO events
with a known cause were the result
of complete or partial blockage of
a sewer line.
differences in the cause of SSO events
between EPA regions. Specifically,
EPA found that nearly three-quarters
of SSO events in the arid Southwest
were caused by blockages, while more
than half of SSO events in Great
Lakes states were attributed to wet
weather and I/I. Therefore, average
regional distributions for SSO cause
were developed and applied in the
estimation of SSO volume in non-
reporting states. More information
on regional trends in SSO cause is
presented in Appendix G.
EPA found that individual SSO event
volumes show a strong correlation
with cause, with the smallest events
attributed to blockages and the largest
events occurring as a result of wet
weather or excessive I/I. As shown
in Table 4.8, the average volume of
SSO events caused by wet weather or
excessive I/I is much greater than the
average volume for any other type of
SSO event.
Additional analysis was performed
on the cause of SSO events in those
communities reporting more than
100 events during a calendar year
(either 2001 or 2002); this analysis
was done to determine whether the
distribution of causes was markedly
different in municipalities reporting
higher numbers of SSO events. As
shown in Figure 4.10, EPA found
that communities reporting higher
numbers of SSO events attributed
a significantly higher percentage of
their SSO events to blockages and a
correspondingly lower percentage of
SSO events to wet weather and I/I.
More detailed information on cause
was available for approximately 80
percent of the more than 12,000 SSO
events attributed to the complete or
Cause Average SSO Median SSO Total Volume
Event Volume Event Volume (million gallons)
(gallons) (gallons)
Blockages
Wet weather and I/I
Mechanical or power
failures
Line breaks
Miscellaneous
5,900
360,000
63,000
172,000
260,000
500
14,400
2,000
1,500
1,200
69
1,860
157
239
199
Percent
of Total
Volume
3
74
6
9
8
Table 4.8
SSO Event Volume by
Cause
Although wet weather and I/I
was listed as the cause for one-
quarter of SSO events, these events
account for nearly three-quarters of
the total SSO volume discharged.
4-27
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure 4.10
Reported Causes of
SSOs in Communities
Reporting More than
100 SSO Events During a
Single Calendar Year
EPA found that communities
reporting higher numbers of SSO
events (>100 per year) attributed a
significantly higher percentage of
their SSO events to blockages.
Causes of SSO Events
V
V
V
V
T
Total
Blockages
Wet weather and I/I
Line breaks
Mechanical or power failures
Miscellaneous
Percent
74%
14%
7%
3%
2%
100%
partial blockage of a sewer line. As
shown in Figure 4.11, grease from
restaurants, homes, and industrial
sources is the most common cause
of reported blockages. Grease is
problematic because it solidifies,
reduces conveyance capacity, and
blocks flow. Grit, rocks, and other
debris that find their way into the
sewer system account for nearly a
third of the reported blockages. Roots
are responsible for approximately
one quarter of reported blockages.
Roots are problematic because they
penetrate weaknesses in sewer lines
at joints and other stress points, and
cause blockages.
4.8 How Do the Volumes and
Pollutant Loads from
CSOs and SSOs Compare
to Those from Other
Municipal Point Sources?
A s described in Section 4.3,
L\ waterbodies receive pollutant
-/. AJoads of the types found in
CSOs and SSOs from other urban and
rural sources. Responsibility for two of
these sources—wastewater treatment
plants and urban storm water
runoff—belongs almost exclusively
to municipalities. Comparing
information on annual discharges
from municipal sources gives context
Figure 4.11
Reported Cause of
Blockage Events
Grease-the most common cause
of blockage-solidifies, reduces con-
veyance capacity,and can eventu-
ally block flow in sewers.
Causes of Blockage Events
V
V
V
V
Total
Grease
Grit, rock, and other debris
Roots
Roots and grease
Percent
47%
27%
22%
4%
100%
4-28
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Chapter 4—Characterization of CSOs and SSOs
to the magnitude of CSO and SSO
discharges. At a national level, as
shown in Table 4.9, the volume of
CSOs and SSOs discharged is one to
two orders of magnitude less than
the total flow processed at wastewater
treatment plants. The volume of urban
storm water runoff generated annually
is nearly equivalent to the volume of
treated wastewater.
In addition to considering the volumes
discharged by various municipal
sources, it is also informative to
consider their relative contributions
in terms of pollutant loads at the
national level. The comparisons of
BOD5, TSS, and fecal coliform loads
presented in Tables 4.10, 4.11, and 4.12
are based on the volumes presented in
Source
Treated wastewater3
CSOb
SSOC
Urban storm water runoffd
a EPA 2000a
b GPRACSO model, Section 4.5.1
c High estimate, Section 4.7.4
Average Discharge Volume
(billion gallons)
11,425
Percent of Total
Municipal Discharges
Annual Discharge Median BOD5 Total BOD5 % of Total
Volume Concentration Load Municipal
(billion gallons) (mg/L) (Ibs.xlO8) BOD5 Load
Treated wastewater
:so
SSO
Urban storm water runoff
7.2
19%
Table 4.9
Estimated Annual
Municipal Point Source
Discharges
On an annual basis,the volume
of CSO and SSO discharged is a
proportionally small amount of the
total flow processed at municipal
wastewater treatment facilities.
Table 4.10
Estimated Annual BOD5
Load from Municipal
Point Sources
CSOs and SSOs contribute to a
relatively low percentage of the
total municipal 6005 load disharged
annually.
1 BODr concentrations taken from the GPRACSO model vary with time, as described in Appendix E.
Source
Treated wastewater
SSO
Urban storm water
runoff
Annual Discharge Median TSS Total TSS Load % of Total
Volume Concentration (IbsxIO8) Municipal
(billion gallons) (mg/L) TSS Load
11,425
850
10
10,068
30
127
91
58
28.5
48.6
33%
10%
< 1%
56%
Table 4.11
Estimated Annual TSS
Load from Municipal
Point Sources
Storm water discharges account for
nearly 60 percent of the municipal
TSS load discharged annually.
it for
ipal
Source
Treated wastewater
Annual Discharge Median FC Total FC Load % of Total
Volume Concentration (MPNxlO14) Municipal
(billion gallons) (#7100 ml) FC Load
11,425
a Assumes wastewater treatment includes disinfection
865
69,172
1,892
19,362
1%
76%
2%
21%
Table 4.12
Estimated Annual Fecal
Coliform Load from
Municipal Point Sources
CSOs appear to be the most
significant source of fecal coliform
when compared to other municipal
point sources on an annual basis.
4-29
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 4.9, and on the concentrations
presented in Tables 4.1, 4.2, and 4.3.
As shown, CSOs and SSOs contribute
a relatively low percentage of the
total municipal BOD5 and TSS load
discharged annually. CSOs, however
appear to be the most significant
municipal source of fecal coliform.
Further, as shown earlier in Figure 4.1,
most CSSs are located in the Northeast
and Great Lakes regions. Therefore,
the fraction of discharge volume and
pollutant load attributed to CSOs in
states with many CSSs and locally in
communities with CSSs is likely to be
much higher. Similarly, communities
experiencing frequent and/or high
volume SSO events are likely to
attribute a larger percentage of the
discharge volume and pollutant load
to SSOs.
BOD5 , TSS, and fecal coliform loads
from several important watershed
sources of pollutants identified in
Section 4.3 of this report, including
agricultural practices and animal
feeding operations, domestic animals
and wildlife, and decentralized
wastewater treatment systems, are not
reflected in these comparisons. It is not
practical to estimate the contributions
of these various sources to the total
annual load of BOD5, TSS, or fecal
coliform on a national level; however,
local examples provide some context.
Relative Contribution of CSOs
to Bacterial Loads:
Rouge River, Ml
A recent study on Michigan's Rouge River (a river with a long history of CSOs and
pollution problems) assessed the relative contributions of CSOs to overall bacterial
indicator loads in the river (Murray and Bona 2001). This study conducted sampling
for fecal coliform and fecal streptococci bacteria at 28 sites within the watershed.
The results of the study suggest that CSOs contribute 10 to 15 percent of the total
bacterial load in the watershed. The authors acknowledge the contributions of
a variety of other sources, including non-CSO municipal sources and nonpoint
sources. The nonpoint sources mentioned as other contributors included wildlife,
domestic animals, rural runoff, contaminated groundwater, and faulty septic
systems.
Relative Contribution of CSOs
to Bacterial and 6005 Loads:
Washington, D.C.
The District of Columbia Water and Sewer Authority quantified pollutant loads
to receiving waters as part of its modeling analysis to support development of
a CSO LTCP (DCWASA 2002). The CSO contribution to the tidal Anacostia River in
Washington, D.C.,was estimated to be 61 percent for fecal coliform and 14 percent
for 8005. Similarly, the CSO contribution to Rock Creek was estimated to be 41
percent for fecal coliform and 6 percent for 8005. Storm water from Washington,
D.C., and suburban areas in Maryland as well as other upstream nonpoint sources
accounted for the remaining loads in both watersheds.
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Chapter 5
Environmental Impacts of
CSOs and SSOs
This chapter describes the
extent to which CSOs and
SSOs cause or contribute to
environmental impacts. The chapter
first discusses EPA's framework for
evaluating environmental impacts
from CSOs and SSOs, using water
quality standards. The chapter then
summarizes environmental impacts
from CSOs and SSOs as reported in
national assessments and presents
the results of new analyses completed
by EPA. Next, site-specific examples
are presented to illustrate the types
of impacts that CSOs and SSOs have
at the local watershed level. Lastly,
the factors that affect the extent of
environmental impacts caused by CSO
and SSO discharges are described.
In conducting data collection
and research for this report, EPA
found that CSOs and SSOs cause
or contribute to environmental
impacts that affect water quality and
the attainment of designated uses.
Pollutant concentrations in CSOs and
SSOs alone may be sufficient to cause
a violation of water quality standards.
Impacts from CSOs and SSOs are
often compounded by impacts from
other sources of pollution such as
storm water runoff, decentralized
wastewater treatment systems, and
agricultural practices. This can make
it difficult to identify and assign
specific cause-and-effect relationships
between CSO or SSO events and
observed water quality impacts and
impairments.
For the purpose of this report,
environmental impacts do not include
human health impacts. The extent of
human health impacts due to CSOs
and SSOs is discussed in Chapter 6.
5.1 What is EPA's Framework
for Evaluating
Environmental Impacts?
EPA's water quality standards
program provides a framework
for states and authorized tribes
to assess and enhance the quality of
the nation's waters. Water quality
standards define goals by designating
uses for the water (e.g., swimming,
boating, fishing) and setting pollutant
In this chapter:
5.1 What is EPA's Framework
for Evaluating
Environmental Impacts?
5.2 What Overall Water
Quality Impacts Have Been
Attributed to CSO and SSO
Discharges in National
Assessments?
5.3 What Impacts on Specific
Designated Uses Have
Been Attributed to CSO
and SSO Discharges in
National Assessments?
5.4 What Overall Water
Quality Impacts Have Been
Attributed to CSO and SSO
Discharges in State and
Local Assessments?
5.5 What Impacts on Specific
Designated Uses Have
Been Attributed to CSO
and SSO Discharges
in State and Local
Assessments?
5.6 What Factors Affect the
Extent of Environmental
Impacts Caused by CSOs
and SSOs?
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Report to Congress on the Impacts and Control ofCSOs and SSOs
limits (criteria) necessary to protect
the uses.
Attainment of water quality standards
is determined through a process of
evaluation and assessment, as follows:
• States adopt water quality goals
or standards that, once approved
by EPA, serve as the foundation
of the water quality-based control
program mandated by the Clean
Water Act.
• States, EPA, and other federal
agencies (e.g., U.S. Geological
Survey) conduct water quality
monitoring studies to measure
water quality and assess changes
over time.
• States compare measured water
quality to goals or standards in
a statewide assessment required
under section 305(b) of the Clean
Water Act and report conditions as
good, threatened, or impaired.
• Waters designated as impaired
are included on a state's 303(d)
list. A total maximum daily load
(TMDL) is required for each
pollutant causing impairment. The
TMDL establishes an allowable
pollutant load that, when achieved,
will result in the attainment of the
water quality standard.
The discussion of environmental
impacts in this chapter is focused on
circumstances in which a designated
use is not being attained due entirely
or in part to CSO and SSO discharges.
The pollutants found in CSOs and
SSOs can potentially impact five
designated uses:
• Aquatic life support, meaning the
water provides suitable habitat for
the protection and propagation of
desirable fish, shellfish, and other
aquatic organisms.
• Drinking water supply, meaning
the water can supply safe
drinking water with conventional
treatment.
• Fish consumption, meaning the
water supports fish free from
contamination that could pose a
significant human health risk.
• Shellfish harvesting, meaning
the water supports a population
of shellfish free from toxics
and pathogens that could pose
a significant health risk to
consumers.
• Recreation, meaning water-
based activities (e.g., swimming,
boating) can be performed
without risk of adverse human
health effects.
As discussed in Section 4.1 of this
report, the principal pollutants
present in CSOs and SSOs are:
microbial pathogens, oxygen depleting
substances, TSS, toxics, nutrients,
and floatables. Table 5.1 summarizes
designated uses likely to be impaired
by each of these pollutants.
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Chapter 5—Environmental Impacts of CSOs and SSOs
Oxygen-demanding substances
Sediment (TS:
Pathogens
Toxics
Nutrients
Floatables
Table 5.1
Pollutants of Concern in
CSOs and SSOs Likely to
Cause or Contribute to
Impairment
The pathogens present in CSO and
SSO discharges have the potential
to impact several designated uses,
including,drinking water supply,fish
consumption,shellfish harvesting,
and recreation.
5.2 What Overall Water
Quality Impacts Have Been
Attributed to CSO and SSO
Discharges in National
Assessments?
States are required to periodically
assess the health of their waters
and the extent to which water
quality standards are being met.
EPA compiles these reports into the
NWQI, which offers a comprehensive
review of water quality conditions
nationwide. This section summarizes
findings from the NWQI and describes
two original analyses undertaken by
EPA to identify potential water quality
impacts from CSO and SSO discharges
at the national level.
5.2.1 NWQI 2000 Report
Since 1975, EPA has prepared a series
of biennial NWQI reports as required
under Section 305(b) of the Clean
Water Act. The NWQI 2000 Report,
the most recently published report, is
a compilation of assessment reports
on the quality of state waters (EPA
2002c). The NWQI Report categorizes
assessed waters as follows:
Good - fully supporting all uses
or fully supporting all uses but
threatened for one or more uses; or
Impaired - partially or not supporting
one or more uses.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
The national summary of the
quality of assessed waters, by type, is
presented in Figure 5.1. This summary
shows that 19 percent of the nation's
total river and stream miles; 43
percent of lake, reservoir, and pond
acres; 36 percent of estuarine and
bay square miles; 6 percent of ocean
shoreline miles; and 92 percent of
Great Lakes shoreline miles were
assessed.
EPA's NWQI2000 Report also
identified the types of pollutants or
stressors most often found to impair
the assessed waters as well as the
leading sources of these pollutants.
These results are presented in Table
5.2 and Table 5.3, respectively. Overall,
EPA found that the three pollutants
most often associated with impaired
waters were solids, pathogens, and
nutrients. All three are present in CSO
and SSO discharges. Therefore, at a
minimum, CSOs and SSOs contribute
Figure 5.1
NWQI 2000 Report: Summary of Assessed Waters by Waterbody Type
(EPA 2002c)
Waterbody assessments are normally based on five broad types of monitoring data: biological
integrity, chemical, physical, habitat,and toxicity. Monitoring data are then integrated for an overall
assessment.
1
verall
Riversand Streams(miles)
Lakes, Reservoirs, and Ponds (acres)
Percent assessed
Assessed as good
Assessed as impaired
61%
39%
55%
45%
Total miles: 3,692,830
Total acres: 40,603,893
Estuaries and Bays (square miles)
Ocean Shoreline (miles)
Great Lake Shoreline (miles)
22%
14%
Total sq. miles: 87,369
Total miles: 58,618
Total miles: 5,521
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Chapter 5—Environmental Impacts of CSOs and SSOs
Pollutant/Stressor
Habitat alterations
Metals
Nutrients
Oil and grease
Oxygen-depleting substances
Pathogens (bacteria)
Pesticides
Priority toxic organic
chemicals
Siltation (sedimentation)
Suspended solids
Total dissolved solids
Turbidity
Rivers Lakes, Estuaries Ocean Great
and Ponds, and Bays Shoreline Lakes
Streams and Shoreline
Reservoirs
Table 5.2
Pollutants and Stressors
Most Often Associated
with Impairment
(EPA 2002c)
Overall, EPA found that the three
pollutants most often associated
with impaired waters were solids
(i.e., suspended solids,siltation,
and total dissolved solids),
pathogens,and nutrients. This
table ranks the top five pollutants
(or stressors) for each waterbody.
Pollutant Source
Agriculture
Atmospheric deposition
Contaminated sediment
Forestry
Habitat modifications
Hydrologic modifications
Industrial discharges
Land disposal
Municipal point sources
Nonpoint sources
Septic tanks
Urban runoff/storm sewers
Rivers Lakes, Estuaries Ocean Great
and Ponds, and Bays Shoreline Lakes
Streams and Shoreline
Reservoirs
1
1
Table 5.3
Leading Sources of
Pollutants and Stressors
Causing Water Quality
Impairment
(EPA 2002b)
Overall, EPA found that pollution
from urban and agricultural land,
transported by precipitation
and runoff, is a leading source of
impairment. This table ranks the
top five pollutant sources causing
water quality impairments.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
to the loading of these pollutants
where they occur.
The NWQI2000 Report did not cite
CSOs or SSOs as a leading source
of impairment in any of the five
waterbody types listed in Table 5.3
(EPA 2002c). CSOs were identified as a
source of impairment for 1,466 square
miles (5 percent) of assessed estuaries
and 56 miles (1 percent) of Great
Lakes shoreline.
The NWQI 2000 Report is based
on a compilation of individual
state assessments, and reporting
of the source of impairment varies
widely from state to state. The lack
of uniformity in assessment and
reporting makes it difficult to fully
assess the magnitude of CSO and
SSO impacts. Inconsistencies in
state reporting of CSOs and SSOs as
pollutant sources are described below.
Unknown sources and failure to
classify: Some states cite unknown
pollutant sources or do not attribute
impairment to a specific source.
Inconsistent source listing: CSOs are
tracked as a specific pollutant source
in many, but not all, states where they
occur. Twenty of the 32 CSO states
identified "combined sewer overflow"
as a source of impairment, in the
NWQI at least once. Where SSOs are
identified by states, they are tracked
in an inconsistent manner. States
use categories such as "collection
system failure (SSO)," "wet weather
discharges," and "spills" for tracking
SSOs.
Cumulative impacts from multiple
pollutant sources: Impacts from CSOs
and SSOs are often compounded
by impacts from other sources of
pollution, particularly during wet
weather. As such, CSOs and SSOs may
be grouped into municipal or urban
source categories.
EPA is working with the states to
develop a framework to promote
consistent listing of sources of
impairment (EPA 2002d).
5.2.2 Analysis of CSO Outfalls
Discharging to Assessed or
Impaired Waters
As described in Section 4.5, a key
EPA initiative undertaken as part of
this report was to update, verify, and
digitally georeference the inventory of
CSO outfall locations documented as
part of EPA's 2001 Report to Congress-
Implementation and Enforcement of
the CSO Control Policy. Through this
effort, EPA established latitude and
longitude coordinates for over 90
percent of CSO outfalls. EPA then
linked CSO outfall locations to other
national-level data and assessments.
For example, permitted CSO outfall
locations were linked to 305(b)-
assessed waters and 303(d)-impaired
waters. These analyses are presented
in the following subsections. A similar
analysis linking permitted CSO outfall
locations with classified shellfish
growing areas is presented in Section
5.3.2. An analysis of CSO outfall
proximity to drinking water intakes
is presented in Chapter 6. More
information on each of these analyses
is provided in Appendix F.
As discussed in Chapter 4, SSOs
do not necessarily occur at fixed
locations. Therefore, a parallel effort
to georeference SSO locations and
evaluate their location with respect
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Chapter 5—Environmental Impacts of CSOs and SSOs
to other national-level data and
assessments was not possible.
outfalls suggests some correlation
between impairment and CSOs.
Analysis of CSO Outfalls Discharging
to EPA's 305(b) Assessed Waters
EPA was able to compare CSO outfall
locations with assessed waters in the
NWQI2000 Report through the 305(b)
assessment database for 19 CSO
states with electronic 305(b) data.
The purpose of this analysis was to
determine the number of CSO outfalls
discharging to waters classified as good
or impaired. EPA limited the analysis
to assessed water segments located
within one mile downstream of a CSO
outfall. The results of this analysis are
summarized in Table 5.4. EPA found
that of the 59,335 assessed water
segments in CSO states with electronic
305(b) data only a small number (733
segments) were in close proximity
to CSO outfalls. Of these, 75 percent
(552 segments) were impaired. The
proximity of a permitted CSO outfall
to an impaired segment does not in
and of itself demonstrate that the
CSO is the cause of the impairment.
CSOs generally are located in urban
areas where waterbodies also receive
relatively high volumes of storm water
runoff and other pollutant loads.
Nevertheless, the high percentage
of impairment associated with CSO
Analysis of CSO Outfalls Discharging
to EPA's 303(d) Waters
EPA also compared CSO outfall
locations to water segments identified
in EPA's Section 303(d) list of impaired
waters in states with NHD-index
data. For the purpose of this analysis,
EPA assumed the causes of reported
Section 303(d) impairment most likely
attributed to or associated with CSOs
were:
• Pathogens
• Organic enrichment, leading to
low dissolved oxygen
• Sediment and siltation
Again, EPA limited the analysis to
water segments located within one
mile downstream of a CSO outfall. The
results of this analysis are summarized
in Table 5.5. EPA found that although
less than one-tenth of one percent
(1,560 of more than 1,495,000) of all
waterbody segments in CSO states
are within one mile of a CSO outfall,
between five and 10 percent of the
waters assessed as impaired are within
that one mile. EPA believes the strong
correlation between CSO location and
impaired waters is due in part to the
Assessed Waters
Assessed 305(b) segments in CSO
states with electronic 305(b) data
Total Assessed as Assessed as Percent
Assessed Good Impaired Impaired
59,335
44,457
14,878 25%
Table 5.4
Occurrence of 305(b)
Assessed Waters Within
One Mile Downstream of
a CSO Outfall
Assessed segments within one mile
downstream of a CSO outfall
733
181
552
75%
EPA was able to complete this
analysis only for states with
electronic 305(b) data; that is, for
19 of the 32 states with active CSO
permits.
. I
"
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Table 5.5
Occurrence of 303(d)
Listed Waters Within
One Mile Downstream
of a CSO Outfall
Waters within one mile of a CSO
outfall are much more likely to
be assessed as impaired than a
typical water in a CSO state.
Listed Waters
Reason or Cause of Listing
Pathogens Enrichment Leading Sediment
to Low Dissolved and
Oxygen Siltation
Total number of listed waters in CSO
states
Number of listed waters within one
mile of a CSO outfall
3,446
191
1,892
163
3,136
149
following factors: CSOs generally
are located in urban areas where
waterbodies also receive relatively
high volumes of storm water runoff
and other pollutant loads; and waters
within urban areas are much are more
likely to be assessed as part of the
305(b) process.
As described in the 305(b) analysis, the
existence of a permitted CSO outfall in
close proximity to an impaired water
does not in and of itself demonstrate
that the CSO is the cause of the
impairment. It does suggest, however,
that CSOs should be considered as
a potential source of pollution with
respect to TMDL development.
EPA has collected anecdotal data
demonstrating that CSOs are being
considered in TMDL development
and that substantial load reductions
have been assigned to CSOs in some
communities as a result of the TMDL
process.
5.2.3 Modeled Assessment of SSO
Impacts on Receiving Water
Quality
The unpredictable nature of most SSO
events makes it difficult to monitor
and collect the data needed to measure
the occurrence and severity of
environmental impacts. As described
in Section 4.7 of this report, however,
EPA was able to compile a substantial
amount of information on the
frequency, volume, and cause of SSO
events. From these data, EPA found
72 percent of these SSO events reach a
surface water.
Using the national SSO data, EPA
developed a simple model for
estimating the likely impact of SSO
events on different size receiving
waterbodies, based on reasonable
assumptions about SSO event
duration and concentrations of fecal
coliform bacteria in SSO discharges.
For the purpose of this report,
modeled impacts associated with
SSO events are evaluated in terms
of violations of the single sample
maximum water quality criterion for
fecal coliform. That is, a predicted
concentration of greater than 400
counts of fecal coliform per 100 mL of
surface water would be considered to
be a water quality standards violation.
The model was run under three
different scenarios: one that assumed
the entire volume of each modeled
SSO discharge reached a surface
water (100% delivery), a second that
assumed half the volume of each
modeled SSO discharge reached a
surface water (50% delivery), and
a third that assumed ten percent of
the volume of each modeled SSO
discharge reached a surface water
(10% delivery).
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Chapter 5—Environmental Impacts of CSOs and SSOs
Flow in a particular waterbody can increase dramatically with a wet weather
event. For example, after an extended period without rain, 2.6 inches of
rain fell in the Washington, DC area over two days in late February, 2004.
This, in turn, caused flow in local waterbodies to increase by varying
amounts-e.g., to 63 times the median flow in the Anacostia River. The
flows given reflect the peak daily flow observed due to this rainfall event.
Waterbody Median Flow February Storm Peak Peak Factor
(cfs) (cfs)
Potomac River
Monocacy River
Goose Creek
Seneca Creek
Anacostia River
8,490
624
250
91
47
79,300
9,130
4,480
1,630
2,950
9
15
18
18
63
Flow varies widely in receiving
waters both from year to year and
seasonally. Flow can also increase
substantially in a particular receiving
water during local wet weather
events. The potential impact of a
specific SSO discharge depends on a
number of factors including flow and
background pollutant concentrations
in the receiving water at the time the
discharge occurs, and the volume and
strength of the discharge that reaches
the receiving water.
The results of EPA's simple model of
SSO-related water quality impacts are
presented in Table 5.6 for a range of
flow conditions, wastewater strength,
and delivery ratios. In general, SSOs
consisting of concentrated wastewater
are predicted to violate water quality
standards the majority of the time,
particularly under low flow conditions.
In contrast, SSOs consisting of more
dilute wastewater are much less likely
to cause water quality standards
violations, particularly under high
flow conditions.
Example: Change in Flow
in Washington, D.C. Area
Waterbodies as a Result of Wet
Weather
Estimated Percentage
Time SSOs Would Cause
Water Quality Standard
Violations
EPA developed a frequency
distribution characterizing typical
volumes of SSO events based on
available data in order to estimate the
likely impact of SSO events on water
quality.
Dilute Wastewater
Flow Rate (FC = 500,000 #/ml)
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Report to Congress on the Impacts and Control ofCSOs and SSOs
A detailed description of the
methodology used to develop these
estimates is presented in Appendix
H. No comparable analysis of SSO
discharges to lake or estuarine waters
was undertaken.
5.3 What Impacts on Specific
Designated Uses Have Been
Attributed to CSO and SSO
Discharges in National
Assessments?
EPA, other federal agencies,
and non-governmental
organizations periodically
conduct national assessments of
environmental impacts that are framed
in terms of the loss of a specific
designated use. Examples include
beach closures in waters designated
for recreation and shellfish harvesting
restrictions in waters designated for
shellfishing. This section summarizes
findings from a number of national
assessments, with emphasis placed on
environmental impacts identified as
being caused, or contributed to, by
CSOs or SSOs.
EPA was unable to identify national
assessments that specifically consider
the impacts of CSOs and SSOs on
aquatic life, although EPA found
several state and local watershed
assessments which do so. These
assessments are discussed in Section
5.5 of this report. Also, for purposes
of this report, impairment of drinking
water supply as a designated use is
considered to be a human health
rather than an environmental impact.
Consequently, drinking water supply is
discussed in Chapter 6 of this report.
5.3.1 Recreation
Recreation is an important designated
use for most waters of the United
States. The results of national
assessments of recreational waters
and the causes of impairment are
described in the following subsections.
EPA BEACH Program
EPA's Beaches Environmental
Assessment and Coastal Health
Program (BEACH Program) conducts
an annual survey of the nation's
swimming beaches, the National
Health Protection Survey of Beaches.
Nearly 2,500 agencies representing
beaches in coastal locations, the
Great Lakes, and inland waterways
participate in the survey. With respect
to designated use impairment during
the 2002 swimming season, 25
percent of the beaches inventoried
(709 of 2,823) had at least one
advisory or closing (EPA 2003a).
Elevated bacteria levels accounted
for 75 percent of recreational use
impairments, manifested as beach
advisories and closings. As shown in
Figure 5.2, a wide variety of pollutant
sources were reported as causing
beach advisories and closings. Nearly
half of the advisories and closings,
however, were reported as having an
unknown cause. CSOs were reported
to be responsible for 1 percent of
reported advisories and closings, and 2
percent of advisories and closings that
had a known cause. SSOs (including
sewer line blockages and breaks)
were reported to be responsible for
6 percent of reported advisories and
closings, and 12 percent of advisories
and closings that had a known cause.
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cso
Figure 5.2
Sources of Pollution
that Resulted in Beach
Advisories and Closings
(EPA 2003a)
EPA's BEACH Program conducts
an annual survey of the nation's
swimming beaches. During the
2002 swimming season, CSOs and
SSOs were responsible for 1 and 6
percent, respectively, of reported
advisories and closings.
Floatables
Floatables are visible buoyant or semi-
buoyant solids that originate from a
variety of sources, including CSOs
and SSOs. CSOs can be a source of
floatables when debris in raw sewage
and storm water is released into the
receiving waterbody. The type of
floatables typically found in CSOs
include sewage-related items (e.g.,
condoms and tampons), street litter,
medical items (e.g., syringes), and
other material from storm drains,
ditches, or runoff (EPA 2002c).
Floatables on beaches and waterways,
also known as marine debris, create
aesthetic impacts and safety issues that
detract from the recreational value of
beaches and other public shorelines.
As defined by the EPA, marine debris
includes all objects found in the
marine environment that do not
naturally occur there. The marine
environment includes the ocean, salt
marshes, estuaries, and beaches.
The National Marine Debris
Monitoring Program (NMDMP),
coordinated by the Ocean Conservancy
(formerly the Center for Marine
Conservation) and funded by EPA,
maintains a national marine debris
database. The NMDMP has conducted
monthly beach cleanups since 1996.
Volunteers track information on
specific marine debris items that are
added to the national database. The
most frequently collected marine
debris items from 1996 to 2002
are presented in Table 5.7 (Ocean
Conservancy 2003).
Medical and personal hygiene items
are an important component of
marine debris. Given the nature and
use of these items and their disposal in
toilets, CSOs and SSOs are considered
a possible source. The Ocean
Conservancy's 2003 International
Coastal Cleanup, a large one-day event,
found a substantial amount of medical
and personal hygiene items on U.S.
beaches (Ocean Conservancy 2004).
More than 7,500 condoms and 10,000
tampons and tampon applicators were
collected from 9,200 miles of U.S.
shoreline during this event. While this
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Table 5.7
NMDMP Marine Debris
Survey Results from
1996-2002 (Ocean
Conservancy 2003)
Funded by EPA is Office of Water,
the NMDMP uses standardized
data collection methods to
determine the status of and
trends in marine debris pollution.
The data are compiled in a
national database.
Marine Debris
(excluding ocean-based)
Straws
Plastic beverage bottles
Other plastic bottles
Balloons
Plastic food bottles
Plastic bottles
Condoms
Syringes
Plastic bags with seam <1 meter
Cotton swabs
Metal beverage cans
Plastic bags with seam > 1 meter
Tampon applicators
Motor oil containers
Six-pack rings
Total Items
information is inconclusive on its own,
it does suggest that CSOs and SSOs
may contribute to the occurrence of
medical and personal hygiene waste
found on beaches and other shorelines.
5.3.2Shellfish Harvesting
Commercial and recreational
shellfishing in populated coastal areas
has declined steadily since the early
1900s, when outbreaks of typhoid
were linked to untreated wastewater.
Environmental impacts that restrict
shellfish harvesting as a designated use
are discussed in the following section.
Human health impacts related to the
consumption of contaminated fish and
shellfish are discussed in Chapter 6.
NOAA National Shellfish Register
NOAA published assessments of
classified shellfish growing waters
in the contiguous states every five
years between 1966 and 1995. The
last report, 1995 National Shellfish
Register of Classified Growing Waters,
provided an assessment of 4,230
different classified shellfish growing
areas in 21 coastal states (NOAA
1997). Areas open for harvesting are
rated as "approved" or "conditionally
approved;" areas where harvesting
is limited are rated as "restricted" or
"conditionally restricted;" and areas
where harvesting is not allowed are
rated as "prohibited."
Findings from the 1995 report with
respect to shellfish harvesting are as
follows:
• 76 percent of all classified waters
were approved or conditionally
approved for harvest (14.8 million
acres);
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• 11 percent of all classified waters
were restricted or conditionally
restricted (3.9 million acres); and
• 13 percent of all classified waters
were prohibited (2.8 million
acres).
NOAA reported that the primary
basis for harvest restrictions was
the concentration of fecal coliform
bacteria associated with untreated
wastewater and wastes from livestock
and wildlife. CSOs are one of many
sources of fecal coliform that impact
shellfish harvesting. A summary of
all pollution sources identified in
the 1990 and 1995 National Shellfish
Registers as causing or contributing
to restrictions and prohibitions is
presented in Table 5.8.
A cooperative effort between the
Interstate Shellfish Sanitation
Conference and NOAA has resulted
in the development of a state Shellfish
Information Management System.
The system will summarize basic
information about shellfish programs
CSO controls implemented in Oswego, NY,
have helped provide suitable habitat for
desirable fish.
Photo: P. MacNeill
Table 5.8
Pollution Sources Reported for Harvest Limitations on Classified Shellfish Growing
Waters in the 1990 and 1995 National Shellfish Registers (NOAA 1997)
Compared to the 1990 Register, the 1995 Register shows significant decreases in the acreage that is harvest-limited
due to contributions from industry and wastewater treatment plants; the acreage impacted by CSOs remained
relatively constant during the five-year period.
ted
Pollution Source
Urban Runoff
Precipitation-related discharges (e.g., septic leachate, animal wastes) from impervious surfaces, lawns,
and other urban land uses
Upstream Sources
Contaminants from unspecified sources upstream of shellfish growing waters
Wildlife
Precipitation-related runoff of animal wastes from high wildlife concentration areas (e.g., waterfowl)
Decentralized Wastewater Treatment Systems
Discharge of partially treated sewage from malfunctioning on-site septic systems
Wastewater Treatment Plants
Routine and accidental sewage discharge from public and private wastewater treatment plants with
varying levels of treatment
Agricultural Runoff
Precipitation- and irrigation-related runoff of animal wastes and pesticides from crop and pasture lands
Marinas
Periodic discharge of untreated or partially treated sewage from berthed vessels
Boating
Periodic discharge of untreated or partially treated sewage from vessels underway or anchored offshore
Industry
Routine and accidental discharges from production/manufacturing processes and on-site sewage
treatment
CSOs
Discharge of untreated sewage/storm water when sewage system capacity is exceeded by heavy rainfall
Total harvest-limited area, in acres
1990a
38%
46%
25%
37%
37%
11%
_
18%
17%
7%
6.4
million
1995a
40%
39%
38%
32%
24%
17%
17%
13%
9%
7%
6.7
million
a Harvest-limited areas are impacted by multiple pollution sources. Annual values do not total 100 percent.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
in each state, replacing NOAA's
national shellfish register. This system,
which will provide spatial data through
a web-based interface, is expected to be
operational in 2004.
Analysis of CSO Outfalls Discharging
Near Classified Shellfish Growing Areas
where shellfish harvesting is currently
prohibited or restricted are in urban
areas in the Northeast where CSOs
are one of several factors that might
account for impairment. Nevertheless,
the association between prohibited and
restricted conditions and the presence
of CSO outfalls is strong.
Table 5.9
Harvest Limitations
on Classified Shellfish
Growing Areas Within Five
Miles of a CSO Outfall
Fifty-eight active CSO permits in nine
states cover outfalls located within
five miles of a classified shellfish
growing area. Shellfish harvesting
is prohibited or restricted in the
majority of the 659 shellfish growing
areas in proximity to CSO outfalls
national database.
EPA associated the location of
individual CSO outfalls with classified
shellfish growing areas as reported
by NOAA in 1995, the last year for
which national data were available.
EPA limited the analysis to classified
shellfish growing areas within five
miles of a CSO outfall. The number
of classified areas was tabulated by
shellfish harvest classification. As
shown in Table 5.9, harvesting was
prohibited or restricted in most
of the classified shellfish growing
areas that are proximate to CSO
outfalls. As discussed earlier under
similar 305(b) and 303(d) analyses,
the presence of a CSO outfall alone
does not necessarily mean that the
CSO is causing or contributing to
the prohibition or restriction. Many
classified shellfish growing areas
Shellfish Harvest Classification
Prohibited
Restricte'
Approved
Unclassified
Total
5.4 What Overall Water
Quality Impacts Have Been
Attributed to CSO and SSO
Discharges in State and
Local Assessments?
State and local governments track
environmental impacts and
gather data for programmatic
reasons that are not necessarily
included in national assessments.
Examples of environmental impacts
included in this section were gathered
from state and local reports and from
watershed studies in which broad
assessments of water quality were
undertaken. These examples are not
meant to be comprehensive. They are
presented to illustrate environmental
impacts attributed to CSO and SSO
Number of Classified Shellfish Growing Areas
within 5 Miles of a CSO outfall
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Chapter 5—Environmental Impacts of CSOs and SSOs
discharges, and, in some instances,
the site-specific circumstances under
which they occurred.
5.4.1 Water Quality Assessment in
New Hampshire
In its 2000 Water Quality Report, New
Hampshire reported that bacteria is
the third leading cause of water quality
impairment in the state, causing or
contributing to 13 percent of the total
miles of impaired rivers and streams
in the state (NHDES 2000). Elevated
levels of bacteria impaired recreational
uses as well as shellfish harvesting
uses in New Hampshire. The overall
sources of water quality impairment to
rivers and streams in New Hampshire
are presented in Figure 5.3. As shown,
unknown sources cause 79 percent of
the 642 miles of impairment reported.
A total of 24.1 miles were impaired
due to CSOs; this represents 3 percent
of all impaired waters in the state and
19 percent of impaired waters with a
known source of impairment.
5.4.2 Water Quality Assessment
of the Mahoning River Near
Youngstown, Ohio
Working in cooperation with
the City of Youngstown, Ohio,
USGS conducted a comprehensive
assessment of water quality and
habitat in the Mahoning River and
its tributaries (USGS 2002). The
City of Youngstown has 80 CSOs
that discharge to local receiving
waters. Water quality monitoring was
conducted during 1999 and 2000. CSO
discharges were found to contribute to
bacterial and nutrient loads observed
in the Mahoning River, but they were
not the only factor adversely affecting
water quality and habitat. USGS found
that:
"Improvement of water quality in
the lower reaches of the Mahoning
River and Mill Creek (a tributary)
to the point that each waterbody
meets its designated-use criteria
will likely require an integrated
approach that includes not only
abatement of sewer overflow
loadings but also identification
and remediation of other loadings
in Youngstown and improvement
of water quality entering
Youngtown."
Other
Figure 5.3
Agriculture
7%
Urban Runoff
2%
CSOs
3%
Municipal Point
Sources
2%
Industrial Point
Sources
2%
Unknown
79%
Sources of Water Quality
Impairment in New
Hampshire (NHDES 2000)
In 2000, New Hampshire reported
a total of 24.1 miles of rivers and
streams impaired by CSOs; this
represents 3 percent of all impaired
waters in the state and 19 percent of
impaired waters with a known sourc
of impairment.
.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
5.4.3 Water Quality in Indianapolis,
Indiana
The City of Indianapolis, Indiana, is
working to identify and implement
CSO controls. The city identified
specific water quality problems in
waterbodies receiving CSO discharges
(City of Indianapolis 2000). The
city's assessment of pollutant sources
contributing to water quality problems
is presented in Table 5.10. As shown,
CSO discharges and wet weather
bypasses at POTWs are ranked high
relative to other sources of pollution.
5.4.4 Water Quality Risk
Assessment of CSO
Discharges in King County,
Washington
King County, Washington, conducted
a CSO water quality risk assessment
for the Duwamish River and Elliot
Bay, an estuary in Seattle (KCDNR
1999). The water quality assessment
consisted of three main parts. First,
more than 2,000 environmental
samples were collected and analyzed
to determine pollutant concentrations
in the water, sediment, and tissues of
aquatic organisms. Six CSO locations
within the estuary were included in
this sampling. The samples were
analyzed for 35 chemical, physical,
and biological attributes. Next, a
computer model was developed to
describe water flow and contaminant
transport within the estuary. The
model was used to estimate current
pollution levels in estuarine water
and sediment as well as to predict
pollution levels after CSO control.
Finally, a risk assessment was
conducted to determine the impacts
of the various pollutants on aquatic
life, wildlife, and people that use
the estuary. Key study findings with
respect to risk reduction resulting
from CSO control are as follows:
• No predicted reduction in risks
for water-dwelling organisms;
• Some predicted reduction in risks
to sediment-dwelling organisms
near the CSO discharges;
• A possible increase in the variety
of benthic organisms near CSOs
as the result of a decrease in
organic matter;
• A possible reduction in impacts
of localized scouring and
sedimentation, which may be
Table 5.10
Relative Contributions
of Pollutant Sources to
Water Quality Problems in
Indianapolis, Indiana (City
of Indianapolis 2000)
Indianapolis ranked the contribution
of CSO discharges and wet weather
bypasses at POTWs high relative
to other sources of pollution in
local receiving waters. Blank
spaces represent negligible or no
contribution in comparison to other
sources.
Pollutant Source Dissolved Oxygen Bacteria Aesthetic
Violations Violations Problems
CSO Discharges
Upstream Sources
Storm Water
Wet Weather Bypass at POTW
Electric Utility Thermal Discharge
Sediment Oxygen Demand
Dams
Water Supply Withdrawals
Septic Tanks
High
High
Low
Low
Low
Low
High
Low
Low
High
Low
High
High
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Chapter 5—Environmental Impacts of CSOs and SSOs
small compared to the overall
scouring impacts of the river and
sediment from other sources; and
• No predicted reduction in risks
to wildlife as other sources
contribute the majority of the
risk-related chemicals.
A stakeholder committee composed
of local citizens, business owners,
environmental organizations, and
tribal governments drew the following
conclusions from the study results:
not meant to be comprehensive.
They are presented to illustrate
representative environmental impacts
attributed to CSO and SSO discharges,
and, in some instances, the site-
specific circumstances under which
they occurred. CSO or SSO discharges
are clearly the cause of documented
environmental impacts in some cases,
and are a contributing factor in others.
Several examples summarize studies in
which impacts from CSOs and SSOs
were sought, but were not found.
• Existing sediment quality and
associated risks to people, wildlife,
and aquatic life in the estuary are
unacceptable;
• Levels of human pathogens and
fecal coliform in the estuary are
unacceptable;
• Controlling CSOs according to the
King County comprehensive sewer
plan will improve some aspects of
environmental quality; and
• Even if CSOs are completely
eliminated, overall environmental
quality of the estuary will
continue to be unacceptable.
5.5 What Impacts on Specific
Designated Uses Have Been
Attributed to CSO and SSO
Discharges in State and
Local Assessments?
Examples of environmental
impacts included in this section
were gathered from state and
local reports and watershed studies;
the examples are presented according
to the designated use impacted by
CSO and SSO discharges. They are
5.5.1 Aquatic Life Support
The designated use for aquatic
life support is achieved when the
water provides suitable habitat for
the protection and propagation
of desirable fish, shellfish, and
other aquatic organisms. Oxygen-
demanding substances are the
principal pollutants found in CSOs
and SSOs that can cause or contribute
to impaired aquatic life support.
CSO and SSO discharges can also
contribute sediment, pathogens,
nutrients, and toxics to receiving
waters, but there is little evidence that
levels of these pollutants in CSOs
and SSOs are major causes of aquatic
life impairment. Select examples
of impacts or relevant studies are
presented below.
Fish Kills in North Carolina
Reports of impaired aquatic life (i.e.,
fish kills) have been investigated
and documented in North Carolina
since 1997 (NCDENR2003). A
summary of fish kills attributed to
sewage spills from 1997 to 2002 is
presented in Table 5.11. As shown,
SSOs are a relatively small cause of the
documented fish kills. Other causes of
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 5.11
Fish Kills Reported in
North Carolina: 1997-
2002 (NCDENR 2003)
Between 1997 and 2002, NCDENR
attributed the deaths of nearly
10,000 fish to SSOs (sewer spills).
Year Total Number Number of Fish Total Number Number of Fish Killed
of Fish Kills Kills Attributed to of Fish Killed in Events Attributed to
Sewer Spills Sewer Spills
1997
1998
1999
2000
2001
2002
fish kills include chemical spills, heavy
rainfall, eutrophication, low dissolved
oxygen due to unspecified causes,
natural phenomena (e.g., temperature
and salinity effects), and unknown
causes.
Individual fish kill events linked to
sewage spills in North Carolina are
presented in Table 5.12. Descriptive
comments provided by field crews
investigating the fish kills are listed in
an abbreviated manner. The oxygen-
depleting substances in the spilled
sewage appear to reduce oxygen
levels to a point at which there is
insufficient oxygen to support aquatic
life, particularly when spills occur in
relatively small streams. No North
Carolina communities are served by
CSSs.
Assessment of SSO Impacts on Fish
and Aquatic Life at Camp Pendleton,
California
In September 2000, an SSO occurred
at the Marine Corps Base Camp
Pendleton near Oceanside, California.
The California State Water Resources
Control Board investigated the spill,
monitored water quality, and assessed
the impact of the spill on fish and
aquatic life (Vasquez 2003). The SSO
occurred at a deteriorated access port
in a sewer force main operated by
the Marine Corps. An estimated 2.73
million gallons of sewage was spilled
over an eight-day period. Data showed
that dissolved oxygen levels in the
impacted area dropped below 1 mg/L,
well below the numeric criteria of 5
mg/L and levels needed to support
most aquatic life, and remained low
for several days. The assessment of
impacted wildlife documented 320
dead fish, 67 dead shrimp, 169 dead
clams, 1 dead snail, and 1 dead bird.
Assessment of PCBs in the Buffalo
River, New York
Polychlorinated biphenyls (PCBs)
are a contaminant of concern for the
Buffalo River in New York and the
Great Lakes in general. PCB levels
in the river often exceed state water
quality criteria, and PCBs found in
fish tissue exceed levels allowed by
the Food and Drug Administration.
In 1994, a study was conducted
to identify sources of PCBs to the
Buffalo River (Loganthan et al. 1997).
Monitoring was conducted in the 700-
acre Babcock Creek sewershed, one
of 27 sewersheds served by combined
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Chapter 5—Environmental Impacts of CSOs and SSOs
Table 5.12
Fish Kills Caused by Sewage Spills in North Carolina: 1997 - 2001
(NCDENR2003)
Oxygen-depleting substances in SSOs (sewer spills) can reduce in-stream dissolved oxygen to levels that
are insufficient to support aquatic life.
Date Waterbody
Investigated
7/1/97
7/14/97
7/29/97
8/13/97
8/14/97
8/19/97
9/23/97
10/7/97
11/9/97
1/5/98
3/16/98
7/6/98
6/29/99
4/13/00
6/9/00
5/3/01
10/23/01
Tributary to Cokey Swamp
Elerbee Creek
Tributary to Elerbee Creek
Swift and Mahlers Creeks
Tributary to Northeast Creek
Coon Creek
Little Buffalo Creek
Lovills Creek
East Beaverdam Creek
Cooper's Pond
Unnamed Lake
Reedy Fork Creek
Muddy Creek
South Fork Catawba River
Town Branch
Subdivision Pond
Tributary to Hare Snipe Cree
Number of Comments
Fish
Killed
300 Spill of at least 23,000 gallons of sewage
120 Sewer spill at storm drain due to sump overflow
100 30,000 gallon spill at pump station
1,000 500,000-1,000,000 gallon sewer line spill
200 20,000 gallon sewer line spill
3,500 1,200,000 gallon spill at pump station
50,000 gallon sewage spill
Sewage leakage at junction in sewage lines
500,000 spill at broken manhole
Sewage spill
114,000 gallons spilled
3,000 gallons spilled at pump station
Sewer overflow reported in area
200 3,000 gallons spilled
5,200 gallons spilled due to blockage
Sewage overflow
40,000 gallon sewage spill
sewers in the City of Buffalo. The
study detected the presence of PCBs
in CSO discharges from the Babcock
Creek CSO outfall and confirmed
that the city's CSS was a source of
PCBs to the river. Monitoring at other
study locations as well as watershed
modeling indicated that the PCB
loadings from unknown, non-CSO
sources were more than 10 times
greater than the loading from all of
the CSOs in the lower Buffalo River
(Atkinson et al. 1994).
Whole Effluent Toxicity of CSO
Discharges in Toledo, Ohio
Whole effluent toxicity testing uses
Ceriodaphnia dubia (water flea)
and Pimephales promelas (fathead
minnow) to measure if a discharge
is toxic. The City of Toledo, Ohio,
conducted whole effluent toxicity
testing on samples collected at four
separate CSO outfalls during wet
weather conditions (Jones & Henry
Engineers 1997). In comparison
with laboratory control groups,
acute (short-term) toxicity was
observed in samples from two CSO
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Report to Congress on the Impacts and Control ofCSOs and SSOs
outfalls, and chronic (long-term)
toxicity was observed in samples from
the other two CSO outfalls. Some
chronic toxicity effects were also
observed in river samples taken above
and below the CSO discharges. Parallel
modeling analysis of CSO discharges
by the City of Toledo identified copper,
lead, silver, and zinc as pollutants of
concern.
As a result of the testing, Toledo
recently developed a draft Industrial
Wastewater Release Minimization
Plan with policies and procedures for
minimizing the discharge of industrial
wastewater during CSO events (City
of Toledo 2003). The plan includes
a variety of measures to reduce
the volume and concentration of
industrial wastewater discharged to the
CSS during wet weather events. Eight
industrial facilities identified as having
the potential to contribute toxics to
CSO discharges have implemented or
scheduled changes to their operations
to reduce flow, load, or both. The
city plans to contact the remaining
industrial facilities participating in its
Industrial Pretreatment Program to
encourage operational modifications to
reduce the volume and concentration
of wastewater discharged to the CSS
during wet weather events.
Analysis of Toxics in CSOs in
Washington, D.C.
The District of Columbia Water and
Sewer Authority monitored its CSO
outfalls for nine months during 1999
and 2000 (DCWASA 2002). The
purpose of the monitoring was to
characterize the chemical composition
of CSO discharges in order to assess
the potential for receiving water
impacts. Monitoring was carried out
for 127 priority pollutants including:
• Total recoverable metals and
cyanide
• Dissolved metals
• Pesticides and PCBs
• Volatiles and semivolatiles
The CSO monitoring data reported
by the Water and Sewer Authority
indicated that all results for priority
pollutants were below the laboratory
method reporting limits, except for
cyanide, chloroform, and several
metals. The cyanide and chloroform
concentrations were found to be
well below the applicable water
quality criteria. Further evaluation of
detected metals showed that all but
dissolved copper and dissolved zinc
were at acceptable levels. Additional
analysis using the EPA-approved
CORMIX and Biotic Ligand models
indicated that the effective instream
concentrations of dissolved copper and
dissolved zinc were also at acceptable
levels. Although Washington, D.C. is
not a heavily industrialized city, 25
permitted significant industrial users
and approximately 3,000 smaller
commercial dischargers (e.g., medical
facilities, printing and photocopying
facilities) discharge to its sewer system.
Fish Diversity in Chicago-area
Waterways
Prior to the implementation of
wastewater treatment facility upgrades
in the 1970s and CSO controls in
the 1980s, aquatic life suffered in
urban Chicago-area streams. The
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Chapter 5—Environmental Impacts of CSOs and SSOs
ability of Chicago-area waterways to
support a rich and diverse aquatic
community was severely limited
by inadequate levels of wastewater
treatment, discharges of chlorinated
effluent at treatment facilities,
and CSO discharges. In particular,
CSO discharges contributed large
amounts of oxygen-demanding
organic substances that depressed
oxygen levels in the waterways, and
the presence of chlorine in treatment
plant effluent contributed to
conditions that were toxic to aquatic
life. Improved wastewater treatment,
including facilities to dechlorinate
treated wastewater, and CSO control
over the past 30 years have improved
the richness and diversity of aquatic
life. As shown in Figure 5.4, the total
number of fish species found and
supported in the principal waterways
in Chicago has expanded during this
period (MWRD 1998).
5.5.2 Recreation
Primary contact and secondary
contact recreation uses are protected
when a waterbody supports swimming
and other water-based activities,
such as boating, without risk of
adverse human health effects from
contact with the water. The principal
pollutants found in CSOs and SSOs
that affect recreational uses at beaches
are microbial pathogens and, to a
lesser extent, floatables. Select local
examples of impacts to recreational
uses and relevant studies are presented
below. Additional information about
potential human health impacts
from recreational exposure to water
contaminated by CSO or SSO
discharges is presented in Chapter 6.
Beach Closures in California
SSOs were identified by the California
State Water Resources Control Board
as one of several sources of beach
pollution in its California Beach
Closure Report 2000 (CSWRCB
2001). Beach closures result from
exceedences of bacterial standards. A
closure provides the public with notice
that the water is unsafe for contact
recreation (i.e., swimming poses an
unacceptable risk of illness).
The majority of beach closures during
2000 were attributed to unspecified
creek and river sources. As shown in
3 7Ql
| 60 H
5" 50 1
^ 40
LL.
"o 30
| 20
£
3
10
0
1974 1978 1982
1986 1990
Year
1994 1998 2002
Fish Species Found in
the Chicago and Calumet
River System, 1974 - 2001
(MWRD 1998; Dennisen
2003)
The total number of fish species
found in the Chicago and Calumet
River system increased six-fold
between 1974 and 2001
:ies
umet
d
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure 5.5
Sources of Contamination
Resulting in California
Beach Closures in 2000
(CSWRCB2001)
In California, problems with sewer
lines such as line breaks; blockages
due to grease, roots, or debris;
and pump station failures have
been identified as the cause of a
to a significant number of beach
closures.
Sources of Contamination
Resulting in Beach Closures
Percent
\/ Unspecified river sources
58%
SSOs
42%
CSOs
\/ Unknown
Total
Figure 5.5, SSOs accounted for 42
percent and CSOs accounted for less
than one percent of all beach closures
in California during 2000. California
has only two communities with CSSs:
San Francisco and Sacramento.
A summary of beach closures due to
SSOs in California in 2000 is presented
in Figure 5.6. The total number of
days that at least one beach was closed
is presented in the map by county.
The accompanying bar graph shows
closures by county in beach-mile
days, a measure of beach availability
for recreation that integrates miles of
beach closed with days of impairment.
Beach Closures in Connecticut
The Connecticut Council on
Environmental Quality reported
on beach closures in the state in its
2001 Annual Report (CTCEQ 2002).
Connecticut's goal is to eliminate
beach closures caused by discharges
of untreated or poorly treated
wastewater, which Connecticut
identified as the most common cause
of elevated bacteria levels. Currently,
several towns close beaches following
a heavy rainfall as a precaution,
100%
presuming that CSO, SSO, and
storm water discharges will occur
and contaminate water. The average
number of days that beaches are closed
depends largely on the frequency and
amount of rainfall during the beach
season. The long-term trend in beach
closures reported by the Council is
presented in Figure 5.7.
Beach Closures in Orange County,
California
Orange County monitors and reports
on bacteria levels along 112 miles of
its ocean and bay coastline. Major
findings documented in its Annual
Ocean and Bay Water Quality Report
(Orange County 2002) are:
• The total number of SSOs
reported to the Orange County
Health Care Agency has steadily
increased over the past 15 years.
• The total number of ocean and
bay beach closures due to SSOs
has increased each year since 1999.
• The total number of beach mile-
days lost as a result of sewage spills
has remained constant since 1999.
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Chapter 5—Environmental Impacts of CSOs and SSOs
Beach Mile-Days
Figure 5.6
San Diego
Orange
San Mateo
Los Angeles
Monterey
Mendocino
Ventura
Sonoma
San LuisObispo
353.4
133.6
• 3.9
I 2.6
I 0.7
I 0.4
I 0.1
Beach Mile-Days is the product of the number
of miles of coastline and the number of days
of impairment.
187
Beach Closures in
California During 2000
Attributed to SSOs
(CASWRCB2001)
During 2000, nine coastal counties
in California reported beach
closures as a result of SSOs. Beach
closure statistics are presented two
ways.The number shown in each
county indicates the total number
of days that are least one beach in
the county was closed in 2000. The
number of lost beach mile-days
in each county is presented in the
adjacent bar chart.
n
1987 1989 1991 1993 1995 1997 1999 2001
Year
\verage Number of
Days per Year Coastal
Municipalities in
Connecticut Closed One
or More Beaches (CTCEQ
2002)
Yearly variations in beach closures
are a product of rainfall patterns
and incidents such as sewer line
ruptures. In 1999,a relatively
dry summer led to less than two
closings, on average.The sharp
increase in beach closings in 2000
was the result of a rainy summer.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Summary of
Unauthorized Wastewater
Discharges in Orange
County, California,
that Resulted in Beach
Closures (Mazur 2003)
Blockages were identified as the
cause of approximately three-
quarters of all unauthorized
wastewater discharges that resulted
in beach closures in Orange County
between 1999 and 2002.
Cause of Discharge
Line breaks
Blockages
Pump station failures
Treatment plant discharges
Miscellaneous
Total unauthorized discharges
1999
38
210
14
0
14
276
2000
55
288
8
0
25
377
2001
69
308
15
4
16
412
2002
95
409
11
2
2
522
A summary of the specific types of
unauthorized wastewater discharges
that resulted in beach closures is
presented in Table 5.13. As shown,
the total number of unauthorized
discharges resulting in beach closures
increased steadily between 1999 and
2002. However, during this same time
period the total number of beach mile-
days lost as a result of sewage spills has
remained constant, suggesting that the
impacts from individual spills have been
reduced. The Orange County Health
Care Agency attributes the reduced
impacts to improvements in wastewater
utility response procedures and increased
regulatory oversight.
Lake Michigan Beach Closures
The Lake Michigan Federation tracks
beach closures in Michigan, Indiana,
Illinois, and Wisconsin based on
data collected from local health
departments, parks managers, and
other municipal agencies. EPA and
NRDC data were used to augment
these sources prior to 2000. The
Federation's tabulation of beach
closures from 1998 to 2002 for all of
Lake Michigan is presented in Figure
5.8. The Federation believes that CSOs
are associated with a high percentage
of the beach closures. Other sources
of pathogens that cause or contribute
to beach closures include wildlife,
storm water runoff, direct human
contamination, and re-suspension
of bacteria in sediment (Brammeier
2003).
To examine whether CSOs were
responsible for beach closures and
advisories along Lake Michigan
in Cook County, Illinois, the
Metropolitan Water Reclamation
District of Greater Chicago conducted
independent research into river
reversals to Lake Michigan (MWRD
2003). River reversals to Lake
Michigan occur when, due to heavy
rainfall, the gates that separate Lake
Michigan and the Chicago River are
opened. River water impacted by
CSOs is discharged to the lake during
river reversals. Swimming at nearby
beaches is preemptively banned for
two consecutive days by park officials
when river reversals occur.
In its report, the District noted hat
river reversals (and thus the discharge
of CSO-impacted waters) to Lake
Michigan were infrequent and did
not explain most beach closings and
advisories (MWRD 2003). Other
sources of bacteria at Chicago beaches
include sea gulls and bacteria in sand
deposits (USGS 2001).
5-24
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Chapter 5—Environmental Impacts of CSOs and SSOs
„ 1000n
2!
2 800 -i
_o
U 600 H
o
£ 400-|
_Q
I 200 H
1998
1999
2001
2002
5.5.3 Shellfish Harvesting
The designated use of shellfish
harvesting is achieved when a
waterbody supports a population
of shellfish free from toxics and
pathogens that could pose a significant
human health risk to consumers.
Accordingly, the principal pollutants
in CSO and SSO discharges found to
impact this use are pathogens, and, to
a lesser extent, toxics. An example of
shellfishing restrictions imposed as a
result of SSO discharges is presented
below.
Shellfish Harvest Limitations as a
Result of SSO to the Raritan River,
New Jersey
On March 2, 2003, a 102-inch
diameter sewer in Middlesex
County, New Jersey, ruptured and
spilled untreated wastewater into
residential areas and the Raritan River.
Approximately 570 million gallons
of wastewater were discharged over
a nine-day period while the pipeline
was being repaired. Daily monitoring
tracked the movement of elevated
bacteria levels in the river (NJDEP
2003). The spill caused high levels of
fecal coliform in nearby, downstream
waters including Raritan Bay, Sandy
Hook Bay, and the Navesink River.
EPA and the New Jersey Department
of Environmental Protection (NJDEP)
sampled affected waters daily and
determined that fecal coliform counts
were highest in the Raritan Bay
(2,400-4,500 fecal coliform counts
per 100 mL); counts were also high
in Sandy Hook Bay (up to 1,100
fecal coliform counts per 100 mL).
Once the spill was stopped, levels
of fecal coliform dropped to below
88 counts per 100 mL throughout
the river and bay system. By March
15, 2003 (two weeks after the spill
began), the highest level reported was
in the western end of Raritan Bay
at an acceptable level of 43 counts
per 100 mL. Fecal coliform was not
detected at nearby ocean beaches. The
movement of the bacteria plume and
its dissipation and dilution over time
are illustrated in Figure 5.9.
The spill forced NJDEP to close
shellfish beds totaling approximately
30,000 acres in Raritan and Sandy
Hook Bays, as well as in the Navesink
and Shrewsbury Rivers. Of the total
acres closed, more than 6,000 acres
were reopened after four weeks,
and an additional 20,000 acres were
reopened after six weeks (NJDEP
2003).
Figure 5.8
Lake Michigan Beach
Closures, 1998-2002
(Brammeier 2003)
During the 2002 swimming season,
authorities issued a total of 919
beach closures and advisories for
Lake Michigan. Of the 34 Lake
Michigan coastal counties,65
percent were monitored for beach
pollution, up from 50 percent in
2000.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure 5.9
Movement of Bacteria
Plume from SSO
Discharge in Raritan Bay,
New Jersey (NJDEP 2003)
This large SSO event (570 million
gallons over nine days, beginning
on March 2,2003) resulted in the
closure of more than 30,000 acres
of shellfish beds for four to six
weeks, until shellfish tissue was clear
of fecal coliform, viral, and metal
contamination. Data are not shown
for the Navesink River and portions
of Sandy Hook Bay.
I 1 Land
Fecal Coliform Results
(MPN/lOOOmL)
0-88
88-500
500-1000
1000-1500
1500-2000
2000-2500
2500-3000
^H 3000-3500
^H 3500^)000
• 4000-5000
Monmoutn
County
I I Land
Fecal Coliform Results
[MPN/lOOOmL)
88-500
500-1000
1000-1500
1 500-2000
2000-2500
2500-3000
3000-3500
3500^1000
4000-5000
Monmouth
County
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Chapter 5—Environmental Impacts of CSOs and SSOs
5.6 What Factors Affect the
Extent of Environmental
Impacts Caused by CSOs
and SSOs?
Compiling and presenting
information on the extent of
environmental impacts caused
by CSOs and SSOs is complicated by
a number of factors. At the local level,
site-specific water quality impacts
vary depending on the volume and
frequency of CSO or SSO discharges,
the size and type of waterbody that
receives the overflows, other sources
of pollution, and the designated uses
for the waterbody. Depending on
the particular combination of these
factors, impacts from CSOs and SSOs
can be visible and intense or relatively
minor. Further, because CSO and SSO
discharges are intermittent and often
occur during wet weather, resulting
impacts can be transient and difficult
to monitor. This section discusses
key factors, including timescale and
receiving water characteristics, that
affect the extent of environmental
impacts caused by CSOs and SSOs.
5.6.1 Timescale Considerations
Although CSO and SSO discharges
are intermittent, the resultant impacts
may not be temporary and can persist
to varying degrees. Some impacts,
such as aesthetic impairment due to
the presence of floatable material,
occur immediately when sewers
overflow and are considered short-
term impacts. In contrast, nutrients
discharged with CSOs and SSOs can
contribute to eutrophication on a
time scale of weeks or months; such
impacts are classified as long-term
impacts. Similarly, chronic toxicity
impacts associated with metals,
pesticides, and synthetic organic
compounds that contaminate both
waterbodies and sediments can affect
aquatic systems over decades.
5.6.2 Receiving Water
Characteristics
The degree to which a CSO or SSO
discharge produces an environmental
impact in a particular waterbody
depends on the rate and volume of the
discharge, the degree of mixing and
dilution, and the assimilative capacity
of the waterbody (see Section 5.2.3).
In general, the larger the waterbody
and the smaller the discharge, the
less likely it is that environmental
impacts will occur. In contrast,
small waters with little dilution and
little assimilative capacity can be
severely impacted by relatively small
discharges.
Once pollutants are discharged into
a waterbody, fate and transport
processes determine the extent and
severity of environmental impacts.
Small-scale hydraulics, such as water
movement near a discharge point,
determine the initial dilution and
mixing of the discharge. Large-scale
water movement due to river flow
and tidal action largely determine the
transport of pollutants over time and
distance. Processes identified as most
important in assessing the impacts of
CSOs and SSOs include:
• Dilution and transport of
pathogens and toxics in the water
column;
• Deposition of settleable solids;
• Resuspension or scour of
settleable solids; and
• Chemical exchange or dilution
between the water column and
sediment pore water (Meyland et
al. 1998).
5-27
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Chapter 6
Human Health Impacts of CSOs
and SSOs
In addition to causing and
contributing to the environmental
impacts reported in Chapter
5, CSOs and SSOs can cause or
contribute to human health impacts.
Microbial pathogens and toxics can
be present in CSOs and SSOs at levels
that pose a risk to human health.
Human health impacts occur when
people become ill due to contact
with or ingestion of water or shellfish
that have been contaminated with
microbial pathogens or toxics.
Although it is clear that CSOs
and SSOs contain disease-causing
pathogens and other pollutants, EPA
found limited quantitative evidence
of actual human health impacts
attributed to specific CSO and
SSO events. Factors such as under-
reporting and incomplete tracking
of waterborne illness, the presence of
pollutants from other sources, and
the use of non-pathogenic indicator
bacteria in water quality monitoring
often make it difficult to establish a
cause-and-effect relationship between
human illnesses and CSO and SSO
discharges.
This chapter documents and expands
the current understanding of human
health impacts from CSOs and
SSOs. The chapter first describes
the pollutants commonly present in
CSOs and SSOs that can cause human
health impacts. The next sections
discuss human exposure pathways;
demographic groups and populations
that face the greatest exposure and
risk of illness; and ways in which
human health impacts from CSOs and
SSOs are communicated, mitigated,
or prevented. The identification and
tracking of illnesses associated with
CSOs and SSOs are also discussed.
Several examples of human health
impacts are provided in the chapter.
6.1 What Pollutants in CSOs
and SSOs Can Cause
Human Health Impacts?
The principal pollutants present
in CSOs and SSOs that can
cause human health impacts
are microbial pathogens and toxics.
The presence of biologically active
chemicals (e.g., antibiotics, hormones,
In this chapter:
6.1 What Pollutants in CSOs
and SSOs Can Cause
Human Health Impacts?
6.2 What Exposure Pathways
and Reported Human
Health Impacts are
Associated with CSOs and
SSOs?
6.3 Which Demographic
Groups Face the Greatest
Risk of Exposure to CSOs
and SSOs?
6.4 Which Populations Face
the Greatest Risk of Illness
from Exposure to the
Pollutants Present in CSOs
and SSOs?
6.5 How are Human Health
Impacts from CSOs and
SSOs, Communicated,
Mitigated, or Prevented?
6.6 What Factors Contribute
to Information Gaps in
Identifying and Tracking
Human Health Impacts
from CSOs and SSOs?
6.7 What New Assessments
and Investigative Activities
are Underway?
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Report to Congress on the Impacts and Control ofCSOs and SSOs
and steroids) is also a concern but is
less well understood at this time.
6.1.1 Microbial Pathogens
Microbial pathogens include hundreds
of different types of bacteria, viruses,
and parasites. Microbial pathogens
of human and non-human origin are
present in domestic and industrial
wastewater. The presence of specific
microbial pathogens in wastewater
depends on what is endemic or
epidemic in the local community and
is often transient. Some microbial
pathogens also have environmental
sources. In general, microbial
pathogens are easily transported
by water. They can cause disease in
aquatic biota and illness or even death
in humans. The three major categories
of microbial pathogens present in
CSOs and SSOs are bacteria, viruses,
and parasites. Fungi do not have a
major presence in wastewater (WERF
2003b), and thus in CSOs and SSOs.
Bacteria
Bacteria are microscopic, unicelluar
organisms. Two broad categories
of bacteria are associated with
wastewater: indicator bacteria and
pathogenic bacteria. Indicator bacteria
are common in human waste and
are relatively easy to detect in water,
but they are not necessarily harmful
themselves. Their presence is used
to indicate the likely presence of
disease-causing, fecal-borne microbial
pathogens that are more difficult to
detect. Enteric (intestinal) bacteria
have been used for more than 100
years as indicators of the presence
of human feces in water and overall
microbial water quality (NAS 1993).
Enteric bacteria commonly used as
indicators include total coliform, fecal
coliform, E. coli, and enterococci.
Further discussion of bacterial
indicators is provided in Section 6.6.
Pathogenic bacteria are also common
in human waste and are capable
of causing disease. Human health
impacts from pathogenic bacteria
most often involve gastrointestinal
illnesses. The predominant symptoms
of pathogenic bacterial infections
include abdominal cramps, diarrhea,
fever, and vomiting. Pathogenic
bacteria can also cause diseases such
as typhoid fever, although this is
not common in the United States.
In addition to attacking the human
digestive tract, the pathogenic bacteria
present in CSOs and SSOs can
cause illnesses such as pneumonia,
bronchitis, and swimmer's ear.
Common pathogenic bacteria, typical
concentrations present in sewage
(where available), and associated
disease and effects are summarized in
Table 6.1.
Viruses
Viruses are submicroscopic infectious
agents that require a host in which
to reproduce. Once inside the host,
the virus reproduces and manifests
in illness (EPA 1999c). More than
120 enteric viruses are found in
sewage (NAS 1993). The predominant
symptoms resulting from enteric virus
infection include vomiting, diarrhea,
skin rash, fever, and respiratory
infection. Most waterborne and
seafood-borne diseases throughout
the world are caused by viruses (NAS
2000). Many enteric viruses, however,
cause infections that are difficult to
detect (Bitton 1999). A list of common
enteric viruses, including typical
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Chapter 6—Human Health Impacts of CSOs and SSOs
Bacteria Concentration
in Sewage3
(per lOOmL)
Campy/o- 3,700 -1 00,000
bacter
Pathogenic 30,000-
£ co// 1 0,000,000
Salmonella 0.2 - 1 1 ,000
S. typhi
Shigella 0.1-1,000
Vibrio
cholera
Vibrio non- 10-1 0,000
cholera
Yersinia
Diseaseb
Gastroenteritis
Gastroenteritis
Salmonellosis
Typhoid fever
Shigellosis
Cholera
Gastroenteritis
Yersinosis
Effects* Infective Dose^d ^^^^^^""^7"
Vomiting, diarrhea
Vomiting, diarrhea,
Hemolytic Uremic
syndrome (HUS),
death in susceptible
populations
Diarrhea, dehydration
High fever, diarrhea,
ulceration of the small
intestine
Bacillary dysentery
Extremely heavy
diarrhea, dehydration
Extremely heavy
diarrhea, nausea,
vomiting
Diarrhea
102-
106-
104-
103-
101-
103-
102-
106
108
107
107
102
108
106
Common Pathogenic
Bacteria Present in
Sewage
Infective dose is defined as the
number of pathogens required to
cause subclinical infection. Infective
doses are typically given as ranges,
as the actual infective dose depends
on the pathogen strain and an
individual's health condition.
^ j
106
a Details in Appendix I
bEPA1999C
c Yates and Gerba 1998
d Lue-Hing 2003
concentrations present in sewage
(where available), and associated
disease and effects are summarized
in Table 6.2. Infective doses are not
reported; enteric viruses typically are
very infectious.
Parasites
Parasites by definition are animals or
plants that live in and obtain nutrients
from a host organism of another
species. The parasites in wastewater
that pose a primary public health
Virus Group
Adenovirus
Astrovirus
Noravi ruses (includes
Norwalk-like viruses)
Echovirus
Enterovirus (includes
polio, encephalitis,
conjunctivitis, and
coxsackie viruses)
Reovirus
Rota virus
Concentration
in Sewage3
(per lOOmL)
10-1 0,000
0.05-100,000
0.1 -125
0.1 - 85,000
Disease1*
Respiratory disease,
gastroenteritis,
pneumonia
Gastroenteritis
Gastroenteritis
Hepatitis, respiratory
infection, aseptic meningitis
Gastroenteritis,
heart anomalies,aseptic
meningitis, polio
Gastroenteritis
Gastroenteritis
Effects b
Various effects
Vomiting, diarrhea
Vomiting, diarrhea
Various effects,
including liver
disease
Various effects
Vomiting, diarrhea
Vomiting, diarrhea
Table 6.2
a Details in Appendix I
bEPA1999C
c Yates and Gerba 1998
d Lue-Hing 2003
Common Enteric Viruses
Present in Sewage
Enteric viruses are typically very
infectious: 1-10 virus particles can
cause infection.
I
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Report to Congress on the Impacts and Control ofCSOs and SSOs
concern are protozoa and helminths
(NAS 1993). Parasitic protozoa
commonly present in sewage include
Giardia lamblia, Cryptosporidium
parvum, and Entamoeba histolytica.
These protozoa cause acute and
chronic diarrhea (NAS 1993). Giardia
causes giardiasis, which is one of the
most prevalent waterborne diseases in
the United States (EPA 2001e).
Ranges of typical concentrations of
protozoa in sewage and information
on infective doses are summarized
in Table 6.3. As shown, ingestion of
a small number of parasitic protozoa
is capable of initiating infection.
Therefore, the presence of low levels
of parasitic protozoa in wastewater
is a greater health concern than are
low levels of most pathogenic bacteria
(NAS 1993).
Helminths, or parasitic worms, include
roundworms, hookworms, tapeworms,
and whipworms. These organisms are
endemic in areas lacking adequate
hygiene. Very little documentation of
waterborne transmission of helminth
infection is available (NAS 1993).
Helminth infections can be difficult to
diagnose and often exhibit no obvious
symptoms.
Indicator Bacteria and Microbial
Pathogens in Sewage
Microbial pathogen concentrations
in sewage vary greatly depending on
the amount of illness and infection in
the community served by the sewer
system. The time of year can also
be important, as some outbreaks of
viral disease are seasonal. Average
concentrations of indicator bacteria
(e.g., fecal coliform) and other
microbial pathogens (enteric viruses
and protozoan parasites) shed by
an infected person are shown in
Table 6.4. These high concentrations
illustrate that a single person shedding
pathogenic organisms can cause a
large pathogen load to be discharged
to a municipal sewer system.
6.1.2 Toxics
As described in Section 4.1 of this
report, toxics are chemicals or
chemical mixtures that, under certain
circumstances of exposure, pose a
risk to human health. Individuals can
suffer chronic health effects resulting
from prolonged periods of ingestion
or consumption of water, fish, and
shellfish contaminated with a toxic
substance. Generally, metals and
synthetic organic chemicals are the
Table 6.3
Common Parasitic
Protozoa Present in
Sewage
Parasitic protozoa have very low
infective doses, which makes their
presence in CSO and SSO discharges
an important public health
concern.
Parasitic
Protozoa
Concentration Diseaseb Effects'1
in Sewage3
(per L)
Cryptosporidium 3-13,700
Crypto-
sporidiosis
Diarrhea
Infective Dosec
1 -150
Entamoeba
4-52
Amedbiasis Prolonged diarrhea
(amoebic with bleeding,abscess
dysentery) of the liver and small
intestine
Giardia
2-200,000 Giardiasis Mild to severe diarrhea,
nausea, indigestion
a Details in Appendix I
bEPA1999C
c Yates and Gerba 1998
10-20
10 - 100
6-4
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Chapter 6—Human Health Impacts of CSOs and SSOs
Organism
Fecal Coliform Bacteria
Enteric Viruses
Protozoan Parasites
toxic substances present in CSO and
SSO discharges that can cause human
health impacts. Metals and synthetic
organic chemicals are introduced into
sewer systems through a variety of
pathways (Ford 1994). These include
permitted industrial discharges,
improper or illegal connections,
improper drain disposal of chemical
remnants, and urban runoff in areas
served by CSSs. While the occurrence
and concentration of specific toxics
in CSOs and SSOs vary considerably
from community to community and
from event to event depending on site-
specific conditions (see Tables 4.4 and
4.5), EPA found no evidence of human
health impacts due to toxics in CSO
and SSO discharges.
Metals
The metals most commonly identified
in wastewater include cadmium,
chromium, copper, lead, mercury,
nickel, silver, and zinc (AMSA
2003a). In CSSs, storm water can also
contribute metals. EPAs Nationwide
Urban Runoff Program (NURP)
identified copper, lead, and zinc in
91 percent of urban storm water
samples collected (EPA 1983a). That
is, all three metals were present in
91 percent of samples. Other metals
commonly detected in urban runoff
include arsenic, cadmium, chromium,
and nickel. The NURP Program
focused on end-of-pipe samples and
Number per Gram of Feces
108 to 109
103to1012
106 to 107
therefore did not consider receiving
water impacts.
Metals are a human health concern
for two reasons. First, metals are
persistent in the environment. This
creates an increased chance of long-
term human exposure once metals are
introduced to a waterbody. Second,
metals such as arsenic, cadmium,
lead, and mercury bioaccumulate
in the human brain, liver, fat, and
kidneys, causing detrimental effects.
Other impacts that can be caused by
metals include dermatitis, hair loss,
gastrointestinal distress, bone disease,
and developmental illnesses.
Synthetic Organic Chemicals
The synthetic organic chemicals that
have been identified in CSOs and
SSOs include chlorinated aromatic
hydrocarbons such as polychlorinated
biphenyls (PCBs), chlorinated
hydrocarbons such as pesticides, and
polycyclic aromatic hydrocarbons.
Synthetic organic chemicals can be
ingested by drinking contaminated
water or by eating contaminated
fish that have bioaccumulated the
chemical. Synthetic organic chemicals
can also be absorbed through the skin.
Their effects on humans range from
skin rash to more serious illnesses
including anemia, nervous system
and blood problems, liver and kidney
problems, reproductive difficulties,
and increased risk of cancer.
Table 6.4
Concentration of
Indicator Bacteria and
Enteric Pathogens Shed
by an Infected Individual
(Schaub1995)
This table shows that a single
infected person can shed a
number of pathogenic organisms.
le
large
nisms.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
6.1.3 Biologically Active Chemicals
Recent research efforts have begun to
consider the presence of biologically
active chemicals—antibiotics, caffeine,
hormones, human and veterinary
drugs, and steroids—in wastewater
(Kummerer 2001). For the most part,
these chemicals have not undergone
extensive analysis for environmental
fate and transport, human health
impacts, or ecological impacts.
Concerns about the presence of these
biologically active chemicals focus on
abnormal physiological processes and
reproductive impairments, increased
incidence of cancer, development
of antibiotic-resistant bacteria,
and potential increased toxicity of
chemical mixtures. Human health
effects, however, are largely unknown
(Kolpin et al. 2002).
Little is known about the effectiveness
of conventional wastewater treatment
processes in the removal of these
biologically active chemicals. The
relative concentrations of these
chemicals in CSOs and SSOs are also
unknown.
6.2 What Exposure Pathways
and Reported Human
Health Impacts are
Associated with CSOs and
SSOs?
Humans may be exposed
to the pollutants found in
CSOs and SSOs through
several pathways. The most common
pathways include recreating in waters
receiving CSO or SSO discharges,
drinking water contaminated by CSO
Sources of Synthetic Organic
Chemicals Deposition:
NY/NJ Harbor
The New York-New Jersey Harbor Estuary Program sponsored studies to estimate
pollutant loads, including loads of synthetic organic chemicals to New York
Harbor. As shown, the studies identified six sources of PCB inputs to the harbor.
Application of a mass balance water quality food chain model for PCBs indicated
that discharges of PCBs to the lower estuary from municipal point sources and
CSOs are significant in causing PCB levels in striped bass to exceed the FDA
standard for fish consumption (NYNJHEP 1996).
Atmospheric
deposition
3%
CSOs
10%
Landfill leachate
Tributaries/
upstream inputs
50%
Municipal
point sources
22%
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Chapter 6—Human Health Impacts of CSOs and SSOs
or SSO discharges, and consuming
or handling fish or shellfish that
have been contaminated by CSO
or SSO discharges. Other pathways
include direct contact with discharges,
occupational exposure, and secondary
transmission.
During wet weather events, CSO- and
SSO-impacted waterbodies typically
receive microbial pathogens and
toxics from a variety of other sources
including municipal and industrial
wastewater discharges, urban storm
water runoff, and agricultural
nonpoint source discharges. These
"interferences" can complicate the
identification of specific cause-and-
effect relationships between individual
CSO or SSO discharges and human
health impacts.
6.2.1 Recreational Water
In the United States, millions of
people use natural waters (e.g., oceans,
lakes, rivers, and streams) each year
for a variety of recreational activities.
The National Survey on Recreation
and the Environment, conducted by
the U.S. Forest Service and NOAA,
describes nationwide participation in
50 categories of outdoor recreation
activities (Leeworthy 2001). The
survey estimates the percentage of the
population, 16 years of age or older,
U.S. Population
(16 and Older)
Percent participating
Number in millions
Boating/Floating <
36%
participating in water-based recreation
activities. Participation in more than
one activity in a single water-based
recreation category is possible (e.g.,
respondents may report both sailing
and canoeing). Data from the most
recent version of the survey (the
period of July 1999 to January 2001)
are presented in Table 6.5.
A number of studies have documented
the risks of gastroenteritis among
people recreating in water
contaminated with microbial
pathogens (NAS 1993; Wade et al.
2003). Recreational exposure generally
comes from contaminants suspended
in the water column entering the body
via oral ingestion. Exposure can also
occur through the eyes, ears, nose,
anus, genitourinary tract, or dermal
cuts and abrasions (Henrickson et
al. 2001). Contact with and ingestion
of ocean water near wastewater or
storm drain outfalls have resulted in
increases in reported respiratory, ear,
and eye symptoms by ocean swimmers
and surfers (Corbett et al. 1993; Haile
et al. 1999).
As described in Chapter 5,25 percent
of the beaches inventoried in EPAs
National Health Protection Survey of
Beaches under the BEACH Program
had at least one advisory or area
closing during the 2002 swimming
Fishing
34%
Swimming'
61%
131
Table 6.5
Participation in Water-
Based Recreation in U.S.
between July 1999 and
January 2001
The National Survey on Recreation
and the Environment estimates
nationwide participation in various
outdoor recreation activities,
including water-based recreation.
Participation in more than one
activity is possible.
a Includes sailing, canoeing, kayaking, rowing, motor-boating, water skiing, personal watercraft use, wind
surfing,and surfing.
b Includes swimming in freshwater or saltwater, snorkeling, scuba, and visiting a beach.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure 6.1
Microbial Pathogens
Linked to Outbreaks
in Recreational Waters,
1985-2000
Shigella was the most commonly
identified cause of waterborne
disease outbreaks linked to
recreational waters between 1985
and 2000. Shigella has a relatively
low infective dose of 10-100 and
is typically found in wastewater in
concentrations of 0.1-1,000 per 100
ml of sewage.
season. Elevated bacteria levels were
cited as the primary cause for 75
percent of these beach advisories or
closures. CSOs were reported to be
responsible for 1 percent of reported
closings and advisories, and 2 percent
of advisories and closures that had
a known cause. SSOs (including
sewer line breaks) were reported to
be responsible for 6 percent of all
reported advisories and closings, and
12 percent of advisories and closing
that had a known cause (EPA 2003a).
Reported Human Health Impacts
A review of CDC Surveillance
Summaries identified 74 waterborne
disease outbreaks linked to open
recreational waters (i.e., rivers, streams,
beaches, lakes, and ponds) from 1985
to 2000. A waterborne disease outbreak
is defined by CDC as two or more
people experiencing similar illness after
exposure to a waterborne pathogen.
A total of 5,601 cases of illness were
attributed to these 74 waterborne
disease outbreaks (CDC 1988,1990,
1992, 1993, 1996a, 1998, 2000, 2002).
The source of the pathogens causing
these waterborne disease outbreaks
was not identified in CDC's reports.
These waterborne disease outbreaks,
however, were caused by the types of
microbial pathogens found in CSOs
and SSOs. Figure 6.1 shows that
Shigella, which is present in CSOs
and SSOs, caused the largest number
of recreational water-associated
outbreaks having a known cause.
Additional information from CDC
Surveillance Summaries on outbreaks
linked to recreational exposure in
fresh or marine waters contaminated
with microbial pathogens is presented
in Appendix I.
CDC Surveillance Summaries also
identify outbreaks linked to swimming
pools or hot tubs. For swimming
pools and hot tubs, 191 recreational
waterborne disease outbreaks with
14,836 cases of illness were reported
to CDC between 1985 and 2000 (CDC
1988, 1990, 1992, 1993, 1996a, 1998,
2000, 2002). This is 265 times the
Other known agents
Norwalk-like
virus
4%
Giardia
4%
Crypotosporidium
Schistosoma spp.
7%
Pathogenic E.coli
13%
Unknown Agent
23%
Shigella
21%
Naegleria fowler!
17%
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Chapter 6—Human Health Impacts of CSOs and SSOs
number of illnesses reported for open
recreational waters.
Estimated Illnesses at Recognized
Beaches
In developing this Report to
Congress, EPA found an absence of
direct cause-and-effect data relating
the occurrence of CSO and SSO
discharges to specific human health
impacts. Lacking comprehensive
data, EPA was able to implement an
alternate approach to estimate the
annual number of illnesses caused
by recreational exposure to CSO and
SSO discharges at a small subset of
the nation's swimming areas—that is,
those recreational beaches recognized
by state authorities ("recognized
beaches"). EPAs illness estimate was
based on existing environmental
and recreational use databases. Data
limitations made it impossible to
develop a comprehensive estimate
of illness at all swimming areas at
this time, but EPA believes that a
significant number of additional
illnesses occur in exposed swimmers
at many inland and unrecognized
beaches.
EPAs estimation of illness at
recognized beaches was limited to
gastrointestinal illness. EPA employed
a multi-step process, including the
following:
• Number of recognized beaches
using specific management
approaches;
• Number of CSO and SSO events
impacting recognized beaches;
• Number of individuals exposed
annually;
• Average concentration of fecal
coliform bacteria at affected
beaches;
• Rate of infection for exposed
population; and
• Total annual number of
gastrointestinal illnesses.
The number of highly credible
gastrointestinal illnesses (HCGI)
resulting from human exposure
to SSOs and CSOs at recognized
beaches was estimated by combining
information on the number
of exposed swimmer days, the
concentration of indicator bacteria
to which swimmers are exposed, and
the Cabelli/Dufour dose-response
functions for marine and fresh
waters. First, EPA calculated the total
number of illnesses caused by CSOs
and SSOs, and then attributed them
separately to CSO illnesses or SSO
illnesses according to the ratio of CSO
to SSO events in the BEACH Survey.
A more detailed presentation of EPAs
methodology is included in Appendix
J.
Results from the analyses are presented
in Table 6.6. The range shown reflects
differences in how compliance rates
with beach advisories were estimated.
The lower bound uses a compliance
rate of 90 percent, and the upper
bound uses a compliance rate of 36
percent. As shown, CSOs and SSOs
are estimated to cause between 3,448
and 5,576 illnesses annually at the
recognized beaches included in this
analysis. This estimate captures only a
portion of the likely number of annual
illnesses attributable to CSO and SSO
contamination of recreational waters.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 6.6
Estimated Illness
Resulting from
Recreational Exposure to
CSOs and SSOs at Select
Beaches
This table shows the portion of the
estimated number of annual illnesses
attributable to exposure to CSO and
SSO contaminated water at state-
recognized beaches in the U.S. and
its territories.
Source
Lower Bound
Upper Bound
6.2.2 Drinking Water Supplies
Public water systems regulated by EPA,
states, and tribes provide drinking
water to 90 percent of Americans (EPA
2002e). Approximately 65 percent of
the population served by these systems
receive water primarily taken from
surface water sources such as rivers,
lakes, and reservoirs. The remaining 35
percent drink water that originated as
groundwater (EPA 1999d).
Reported Human Health Impacts
People can contract waterborne
diseases through consumption of
municipal drinking water, well
water, or contaminated ice. Because
drinking water is directly ingested,
and it is generally ingested in larger
quantities than recreational water that
is accidentally ingested, drinking water
is an important pathway of exposure.
From 1985 to 2000, 251 outbreaks and
462,169 cases of waterborne illness
related to contaminated drinking
water were reported to CDC (CDC
1988, 1990, 1992, 1993, 1996a, 1998,
2000, 2002). The vast majority of
these cases of illness are from a
1993 cryptosporidiosis outbreak in
Milwaukee, Wisconsin, which affected
an estimated 403,000 people; the CDC
did not specifically identify untreated
wastewater as contributing to the
Milwaukee outbreak.
As shown in Appendix I, EPA
identified a subset of 55 of these 251
outbreaks linked to drinking source
water contaminated with human
sewage or to drinking water taken
SSOs linked to Drinking
Water Contamination:
Cabool, MO
Between December 15, 1989, and January 20, 1990, residents of and visitors to
Cabool, Missouri, experienced 243 cases of diarrhea and four deaths (Swerdlow
et al. 1992).The CDC conducted a household survey and concluded that persons
drinking municipal water were 18.2 times more likely to develop diarrhea than
persons using private well water (Geldreich et al. 1992). Observations suggested
that Cabool's SSS was prone to excessive storm water infiltration and therefore was
unable to convey all of the wastewater to the treatment facility. As a result, frequent
capacity-related SSOs occurred, spilling sewage onto the ground surface in areas
over drinking water distribution lines and near water meter boxes. During the
outbreak, the water distribution system was under construction,allowing untreated
sewage to contaminate the drinking water system (Geldreich et al. 1992).
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Chapter 6—Human Health Impacts of CSOs and SSOs
Other known
Shigella agents
Campylobacter
Pathogenic Eco//'
Cryptosporidium
10%
Unknown agent
31%
Microbial Pathogens
Causing Outbreaks
Linked to Drinking Water
1985-2000
Ciardia was responsible for 42
percent of the outbreaks of
waterborne disease linked to
drinking water.
from rivers, streams, or lakes. Of
these, EPA identified 11 outbreaks
accounting for 7,764 cases of
waterborne illness that CDC linked
to drinking water contamination with
sewage. Only one of these outbreaks
was linked directly to CSOs or SSOs.
The outbreaks were caused, however,
by the types of microbial pathogens
found in CSOs and SSOs. As shown in
Figure 6.2, Giardia, which is present
in significant concentrations in CSOs
and SSOs, caused the largest number
of outbreaks linked to drinking water.
A summary of these outbreaks is
provided in Appendix I.
Proximity of CSO Outfalls to Drinking
Water Intakes
As described in Chapter 5 and
documented in Appendix F, EPA geo-
referenced more than 90 percent of
all CSO outfalls. EPA compared the
locations of these CSO outfalls to
drinking water intakes. Only drinking
water systems that serve a community
on a year-round basis and that use
surface water as the primary source
of water were considered in this
analysis. Approximately 7,519 such
systems operate in the United States,
of which 6,631 (85 percent) have been
In July 1998, a lighting strike and the subsequent power outage caused 167,000
gallons of raw sewage to flow into Brushy Creek in Texas (TDH 1998). The sewage
contaminated municipal drinking water wells that supplied the community of
Brushy Creek. Although the wells are not in direct contact with surface waters (the
wells are more than 100 feet deep and encased in cement), drought conditions at
the time are thought to have caused water from Brushy Creek to be drawn down
into the aquifer and into the wells through a geologic fissure. It is estimated that 60
percent of Brushy Creek's population of 10,000 were exposed to Cryptosporidium
and approximately 1,300 residents became ill with cryptosporidiosis. Residents of
Brushy Creek were supplied water from the contaminated wells for approximately
eight days (TDH 1998).
Drinking Water
Contaminated by Sewage:
Brushy Creek, TX
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 6.7
Association of CSO
Outfalls with Drinking
Water Intakes
EPA identified 59 CSO outfalls in
seven states with outfalls located
within one mile upstream of a
drinking water intake.
geo-referenced to the NHD and are
included in this analysis.
All of the drinking water systems
within one mile of any CSO
outfall were selected for further
analysis. As shown in Table 6.7, EPA
identified seven states with outfalls
located within one mile upstream
of a drinking water intake. Phone
interviews were conducted with
both the NPDES permit-holder
and drinking water authority in
the identified areas to confirm the
location of the CSO outfall, the status
of the CSOs (active/inactive), and the
location of the drinking water intake.
In many cases, the NPDES permit-
holder reported that the CSO was
inactive, as a result of sewer separation
or other CSO controls.
EPA identified and confirmed 59
active CSO outfalls within one mile of
a drinking water intake. One NPDES-
permit holder reported that receiving
water modeling found that the
drinking water intake (located within
one mile, but on the opposite side
of the river) was not affected by the
CSO. Interviews with drinking water
EPA Region
authorities found, where a primary
drinking water intake was located
within one mile of an active CSO, each
drinking water authority was aware
of the CSO. Further, in all cases, lines
of communication existed between
the drinking water authority and the
NPDES permit-holder. In many cases
the drinking water authority indicated
adjustments are made to the treatment
process during wet weather.
This assessment indicates that CSO's
generally do not pose a major risk
of contamination to most public
drinking water intakes. However, to
understand the relationship between
a discharge point and a downstream
drinking water intake the transport
and fate of the discharge between the
two points must be modeled under the
range of real world flow conditions for
that stream reach. Such modeling is
beyond the scope of this report.
6.2.3 Fish and Shellfish
Fish and shellfish are widely
consumed in the United States and
are a valued economic and natural
resource (NYNJDEP 2002a). In 1995,
Number of CSO Outfalls within 1 mile
upstream of a drinking water intake
Total:
Note: EPA was unable to confirm data for an additional 14 outfalls in two states ( PA and WV); these outfalls
are not included in this table.
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Chapter 6—Human Health Impacts of CSOs and SSOs
the most recent year for which data
are available, 77 million pounds of
clams, oysters, and mussels were
harvested in the coastal United States
(NOAA 1997). Shellfish grown in
contaminated waters concentrate
microbial pathogens and can have
higher concentrations than the
waters in which they are found.
Viable pathogens can be passed on
to humans by eating whole, partially
cooked, or raw contaminated shellfish.
Reported Human Health Impacts
The World Health Organization
reported that seafood is involved in 11
percent of all disease outbreaks from
food ingestion in the United States
(WHO 2001). The most common
illness associated with eating sewage-
contaminated raw shellfish and fish is
gastroenteritis (CERI 1999).
A review of CDC Surveillance
Summaries identified eight
waterborne disease outbreaks linked to
the consumption of contaminated fish
or shellfish for the period 1985-2000.
These outbreaks resulted in 995 cases
of illness (CDC 1990, 1995, 1996b,
1997). More information on these
outbreaks is provided in Appendix
I. In most cases, the contaminated
fish or shellfish were exposed to or
grown in sewage-contaminated water.
Waste dumped overboard by boaters
and improperly treated sewage were
the most commonly cited sources
of fish and shellfish contamination.
The New York State Department of Health compiled data on shellfish-associated
illness (most commonly gastroenteritis) recorded in New York State from 1980 to
1999 (NYNJHEP 2002b). The incidence of reported illness has dropped markedly
since its peak in 1982. The study was able to trace most of the outbreaks in 1982 to
Rhode Island shellfish.The study noted that it is often difficult to identify the source
of the shellfish that induced the outbreak. Decreases in shellfish-associated disease
are attributed to a number of factors including: improvements in wastewater
treatment leading to reductions in concentrations of waterborne microbial
pathogens; more restrictions on shellfish harvesting in contaminated areas; and
more public awareness of the risks associated with consuming raw shellfish. The
study also noted that although shellfish beds are carefully monitored for pathogenic
contamination, the levels of toxic contaminants in shellfish, including impacts from
marine algal toxins, need additional study.
Number of Reported Outbreaks of Shellfish
Associated Illnesses, New York State
140
120
£ 100
I 80
5 60
2 40
20
0
••
Year
Shellfish-Associated Illness:
New York State
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Direct links to CSO and SSO events
as a cause of contamination were not
made.
6.2.4 Direct Contact with Land-
Based Discharges
Many SSOs discharge to terrestrial
environments including streets,
parks, and lawns. CSSs and SSSs
can also back up into buildings,
including residences and commercial
establishments. These land-based
discharges present exposure pathways
that are different than those pathways
associated with typical discharges to
water bodies. Exposure to land-based
SSOs and building backups typically
occurs through dermal contact. The
resulting diseases are often similar
to those associated with exposure
through drinking or swimming in
contaminated water, but may also
include illness caused by inhaling
microbial pathogens (CERI 1999).
Reported Human Health Impacts
In general, very few outbreaks
associated with direct contact
with land-based SSOs have been
documented. Land-based SSOs
tend to leave visible evidence of
their occurrence, such as deposits of
sanitary products and other wastes
commonly flushed down a toilet. The
presence of these items often acts as
a deterrent to direct contact with the
SSO. Further, municipal response
to land-based SSOs often includes
cleaning the impacted area by washing
the sewage into a nearby manhole
or storm drain and disinfecting as
needed. This review identified one
confirmed outbreak resulting from
direct contact with a discharge of
untreated sewage in Ocoee, Florida.
This event resulted in 39 cases of
hepatitis A (Vonstille 1993).
6.2.5 Occupational Exposures
Many occupational settings
occasionally expose personnel to
microbial pathogens. These include
restaurants and food processing,
agriculture, hospitals and healthcare,
emergency response, and wastewater
treatment.
Wastewater treatment plant workers
and public works department
personnel operate and maintain
wastewater treatment facilities and
respond to CSO or SSO events. In
doing so, they may be exposed to
microbial pathogens present in CSOs
and SSOs. Police, firefighters, rescue
divers, and other emergency response
personnel also face exposure to
CSOs and SSOs. Depending on the
context in which the overflow event
occurs, exposure can occur through
inhalation, ingestion, and dermal
contact. Adherence to good personal
hygiene and the appropriate use of
personal protective equipment are
important in minimizing the potential
for injury or illness.
Reported Human Health Impacts
Comprehensive epidemiologic
research on waterborne illness
associated with occupational exposure
to untreated wastewater is lacking.
Some researchers believe that
wastewater workers may experience
increased numbers of bacterial, viral,
and parasitic infections without
exhibiting signs or symptoms of
illness. These are called "sub-clinical"
infections (AFSCME 2003). One
study concluded that the lowest rates
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Chapter 6—Human Health Impacts of CSOs and SSOs
of illness are found among workers
employed in wastewater treatment
for less than five years, the highest
rates in workers with five to 10 years
of exposure, and lower rates again
in workers with 15 years or more
of exposure (Dowes et al. 2001). An
explanation for this is that workers
build immunity to many of the
microbial pathogens present in the
work environment over the course
of their employment, and those who
become very ill no longer work in the
plant. This phenomenon is also known
as the "healthy worker effect."
In general, the effect of microbial
pathogens, other than hepatitis A, on
wastewater workers has been given
little attention, and "there have been
few epidemiologic studies conducted
among sewage workers in the U.S. to
determine the actual prevalence and
types of infections" (AWR 2001).
One confirmed waterborne disease
outbreak through occupational
exposure was identified from
the review of CDC Surveillance
Summaries. In 1982, 21 cases
of gastrointestinal illness were
identified among 55 police and fire
department scuba divers training
in sewage-contaminated waters
(CDC 1983). The divers developed
gastrointestinal disease more than
four times as frequently as nondiving
firefighters, the control group in the
study. Although the causes of illness
in many divers were not identified,
gastrointestinal parasites were found
in 12 divers: Entamoeba histolytica
in five divers, and Giardia lamblia in
seven divers.
6.2.6 Secondary Transmission
An individual who contracts
an infection from exposure to a
waterborne microbial pathogen may,
in turn, infect other individuals,
regardless of whether symptoms are
apparent in the first individual. This
is commonly referred to as "secondary
transmission." The rate of secondary
transmission depends largely on
the particular microbial pathogen.
Illnesses caused by secondary
transmission are not included in CDC
Surveillance Summaries, which list
only primary illnesses.
Reported Human Health Impacts
Secondary transmission statistics
obtained from a variety of waterborne
and non-waterborne disease outbreaks
are shown in Table 6.8 (NAS 1998). As
presented, the secondary attack ratio
represents the ratio of secondary cases
to primary cases.
6.3 Which Demographic
Groups Face the Greatest
Risk of Exposure to CSOs
and SSOs?
Several demographic groups
face increased risk of exposure
to the pollutants in CSOs and
SSOs because they are more likely to
spend time in locations impacted by
such discharges. These groups include
people recreating in CSO- and SSO-
impacted waters, subsistence fishers,
shellfishers, and wastewater workers.
The sections that follow describe
exposure risks for each of these groups
in greater detail. This information is
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 6.8
Examples of Secondary
Transmission from
Waterborne and Non-
Waterborne Disease
Outbreaks (MAS 1998)
An individual who contracts an
infection may, in turn,infect other
individuals. This table shows for
every two individuals infected with
Norwalk virus, one to two individuals
can become infected via secondary
transmission.
Microbial Pathogen
Cryptosporidium
Shigella
Rotavirus
Giardia
Unspecified virus causing
viral gastroenteritis
Norwalk virus
Secondary Attack Ratio
0.33
0.28
0.42
1.33
0.22
0.5-1.0
Source of Outbreak
Contaminated apple cider
Child day care center
Child day care center
Child day care center
Contaminated drinking water
Contaminated recreational water
presented based on the availability of
literature documenting each group's
potential for exposure, rather than
on the relative sensitivity of each
population to the pollutants in CSO
and SSO discharges.
6.3.1 Swimmers, Bathers, and
Waders
Swimming in marine and fresh water
has been linked directly to diseases
caused by the microbial pathogens
found in wastewater (Cabelli et
al. 1982). For example, a 1998
study comparing bathers and non-
bathers found that 34.5 percent of
gastroenteritis and 65.8 percent of ear
infections reported by participants
were linked to bathing in marine
waters contaminated with sewage.
The percentage of people who lost at
least one day of normal activity due to
contacting one of the illnesses studied
ranged from 7 to 26 percent (Fleisher
etal. 1998).
Many variables influence the exposure
of people to pathogens in recreational
water. These factors include whether
people swim or wade, the type of
pathogens present at the time of
exposure, the route of exposure
(ingestion or skin contact), and
individual susceptibility to waterborne
disease (WSDH 2002).
6.3.2Subsistence and Recreational
Fishers
Subsistence and recreational fishers
and their families tend to consume
more fish and shellfish than the
general population, and men tend to
consume more fish and shellfish than
women (Burger et al. 1999). Further,
in areas conducive to fishing, people
with lower education levels or lower
income levels consume more fish and
shellfish, as it is often an inexpensive
source of protein (Burger et al. 1999).
Cultural preferences influence the
amount and frequency of fish as well
as shellfish consumption and the
methods for preparing and serving
fish and shellfish. For example, a study
of two Native American groups in
Puget Sound in Washington found
that these groups consumed fish at
much higher rates than the general
public and at rates greater than those
recommended by EPA (Toy et al.
1996). Asians and Pacific Islanders
generally consume fish at much higher
rates than the general United States
population (Sechena et al. 1999).
In addition, cooking methods and
consumption rates of parts of the
fish that tend to concentrate toxins
(e.g., skin, head, organs, and fatty
tissue) can increase the risk of human
health impacts from consuming
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Chapter 6—Human Health Impacts of CSOs and SSOs
contaminated fish and shellfish (e.g.,
Wilson et al. 1998; WDNR 2003).
Fish and shellfish advisories target
recreational and subsistence fishers.
Despite warnings and advisories,
however, many fishers consume
their catch. May and Burger (1996)
found that a majority of urban and
suburban recreational fishers ignored
warnings issued by the New York State
Department of Health and the New
Jersey Department of Environmental
Protection.
6.3.3 Wastewater Workers
Wastewater workers are more likely
to come into contact with untreated
wastewater than the general public,
but there is insufficient data to
determine whether wastewater
workers or their families face an
increased risk of illness as a result
of this exposure. Although there is
disagreement regarding the benefits of
additional immunization above those
recommended by CDC for the adult
general population (i.e., diptheria
and tetanus), WERF (2003b) asserts
that wastewater workers should be
vaccinated for both Hepatitis A and B.
6.4 Which Populations Face
the Greatest Risk of Illness
from Exposure to the
Pollutants Present in CSOs
and SSOs?
Certain demographic groups,
including pregnant women,
children, individuals with
compromised immune systems,
and the elderly, may be at greater
risk than the general population for
serious illness or a fatal outcome
resulting from exposure to the types
of pollutants present in CSOs and
SSOs. Specific characteristics of
these demographic groups that make
them particularly susceptible to these
illnesses are discussed in more detail in
the following sections. These sensitive
groups represent almost 20 percent
of the U.S. population (Gerba et al.
1996). Also, tourists and travelers may
be more prone to waterborne illnesses
than local residents (EPA 1983b). EPA
research has found that when exposed
to pathogens found in local sewage,
local residents have been shown to
develop fewer symptoms than non-
residents or visitors.
6.4.1 Pregnant Women
During pregnancy, women appear
to be at greater risk of more serious
disease outcomes from exposure to
the types of enteric viruses found
in CSOs and SSOs (Reynolds 2000).
Waterborne diseases contracted during
pregnancy may result in transfer of
the illness to the child either in utero,
during birth, or shortly after birth
(Gerba et al. 1996).
6.4.2 Children
The incidence of several waterborne
infectious diseases caused by the
types of pollutants present in CSO
and SSO discharges is significantly
greater in infants and children than
in the general population (Laurenson
et al. 2000). Factors contributing to
the susceptibility of children include
children's naturally immature immune
systems and child-associated behaviors
that result in abnormally high
ingestion rates during recreational
exposure to contaminated water
(Laurenson et al. 2000). For example,
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Report to Congress on the Impacts and Control ofCSOs and SSOs
children frequently splash or swim in
waters that would be considered too
shallow for full-body immersion by
adults (EPA 200Ib).
6.4.3 Immunocompromised Groups
People with compromised immune
systems, such as those with AIDS,
organ transplant recipients, and
people undergoing chemotherapy,
are more sensitive than the general
public to infection and illness caused
by the types of pollutants present
in CSO and SSO discharges (Gerba
et al. 1996). Using Wisconsin death
certificate data, Hoxie et al. (1997)
analyzed cryptosporidiosis-associated
mortality in AIDS patients following
the 1993 Milwaukee outbreak that
affected an estimated 403,000 people.
The researchers found that AIDS
was the underlying cause of death
for 85 percent of post-outbreak
cryptosporidiosis-associated deaths
among residents of the Milwaukee
area. Further, the researchers found
that AIDS mortality increased
significantly in the six months
immediately after the outbreak,
then decreased to levels lower than
expected, and then returned to
expected levels. This suggests that
some level of premature mortality was
associated with the outbreak.
6.4.4 Elderly
The elderly are at increased risk for
waterborne illness due to a weakening
of the immune system that occurs
with age (Reynolds 2000). Studies
have found that people over 74 years
old, followed by those between 55
and 74, and then by children under
5, respectively experience the highest
mortality from diarrhea as a result of
infection by waterborne or foodborne
illness (Gerba et al. 1996). Studies
of a giardiasis outbreak in Sweden
that occurred when untreated sewage
contaminated a drinking water supply
found people over 77 years old faced
an especially high risk of illness
(Ljungstrom and Castor 1992).
6.5 How are Human Health
Impacts from CSOs and
SSOs Communicated,
Mitigated, or Prevented?
A variety of programs are in
place to reduce human health
impacts associated with
exposure to microbial pathogens
and toxics. These programs generally
involve preventive measures enacted
by public health officials, including:
communication efforts to warn the
public about risk and threats; and
monitoring, reporting, and tracking
activities. This section is focused on
agencies, activities, and programs
designed to communicate, mitigate,
or prevent potential human health
impacts from exposure to CSOs and
SSOs.
6.5.1 Agencies and Organizations
Responsible for Protecting
Public Health
Numerous agencies and organizations
have responsibilities for monitoring,
tracking, and notifying the public of
potential human health impacts. These
include federal and state agencies,
local public health officials, owners
and operators of municipal wastewater
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Chapter 6—Human Health Impacts of CSOs and SSOs
collection and treatment facilities, and
non-governmental organizations.
Federal Agencies
EPA administers a national water
quality standards program that
establishes criteria to support
designated uses including recreation,
drinking water supply, and shellfish
harvesting. EPA also administers a
national safe drinking water program
with a goal that, by 2005, 60 percent of
the population served by community
drinking water systems will receive
their water from systems with active
source water protection programs
(EPA 1997b). In developing source
water protection programs, EPA
specifically encourages suppliers
to consider CSOs, sewer system
failures, and wet weather municipal
effluent point source discharges as
sources of microbial contamination.
Further, drinking water intakes and
their designated protection areas are
identified as "sensitive areas" under the
CSO Control Policy. The elimination,
control, or relocation of CSO outfalls
that discharge to sensitive areas
are to be given high priority in the
development and implementation of
CSO LTCPs (EPA 1994a).
As discussed earlier in Section 5.5.2
of this report, EPA's BEACH program
conducts an annual survey of the
nation's swimming beaches. The
program was created to reduce health
risks to swimmers due to contact
with contaminated water by working
to improve monitoring and public
notification procedures at beaches.
CDC's National Center for Infectious
Diseases works to prevent illness,
disability, and death caused by
infectious diseases. Waterborne
disease prevention is a priority for this
program. Working with EPA, CDC
coordinates national reporting of
waterborne illness outbreaks through
its Outbreak Surveillance System.
This system compiles state-reported
outbreaks to characterize waterborne
outbreaks epidemiologically (e.g., to
investigate the agents, reasons for the
outbreak, and adequacy of various
treatment methods) and to strengthen
the public health community's ability
to respond. Outbreak summaries
are produced biennially. With
the cooperation of state health
departments and other national
partners, CDC's Division of Parasitic
Diseases and Division of Bacterial and
Mycotic Diseases are responsible for
the investigation, surveillance, and
control of specific groups of diseases,
including many pathogens linked to
waterborne illness.
NOAA works to protect and
preserve U.S. living marine resources
through scientific research, fisheries
management, enforcement, and
habitat conservation. As detailed in
Section 5.3.2 of this report, NOAA
is currently working with Interstate
Shellfish Sanitation Conference
(ISSC), EPA, and FDA to develop an
information resource on shellfish
safety. This data system will house
shellfish growing area monitoring,
survey, and classification data.
FDA administers the National Shellfish
Sanitation Program, an effort intended
to standardize the inspection and
monitoring of shellfish growing
areas and shellfish packing/shucking
facilities. Working with EPA, FDA
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Report to Congress on the Impacts and Control ofCSOs and SSOs
publishes guidance on the safety
attributes of fish and fishery products,
including acceptable levels of organic
and inorganic compounds such as
mercury and PCBs.
USGS plays an active role in
monitoring and reporting the
quantity and quality of the nation's
water resources. USGS helps to assess
water quality problems and sources
of pollution, including CSOs and
SSOs, by studying how pathogens and
other agents of waterborne disease
interact with the environment and by
monitoring and reporting the quality
of the nation's water resources.
State Agencies
State public health agencies track
communicable diseases, perform
outbreak investigations, and issue
warnings to the public. These agencies
integrate and compile findings
from local efforts, and they provide
coordination with other state and
federal agencies and programs. This
coordination includes providing
data on waterborne illness and
investigations to CDC.
State environmental agencies conduct
water quality monitoring and
assessment programs and require
monitoring to be conducted by others,
such as local sanitation districts,
public water systems, regional
planning agencies, and recreational
facilities. State environmental or
natural resource agencies also
monitor fish and shellfish. These
monitoring programs provide data
for management decisions at the state
level in response to environmental and
public health concerns. In addition
to monitoring, state agencies perform
sanitary surveys to identify problems
that could affect the safety of the
drinking water supply. A sanitary
survey is a physical inspection of the
Coastal Beach
Monitoring Program:
Connecticut
Beach Monitoring and
Public Notification Program:
Rhode Island
The State of Connecticut has a comprehensive monitoring program for its coastal
waters, with standards and guidelines set by the state. The state collects and
analyzes samples taken at four coastal state parks on Long Island Sound. At least
18 municipalities in the state's four coastal counties monitor their own beaches,
following the ocean and bay beachwater-quality monitoring protocol established
by the Connecticut Departments of Public Health and Environmental Protection. In
2002, Connecticut set aside a $226,000 grant to integrate monitoring at municipal
beaches into a state-administered sampling and public notification plan for the
entire state. The beach grant funded a courier service to bring municipal beach
samples to the Department of Public Health lab, where the state analyzes the
samples free of charge.
The Rhode Island Health Department requires every licensed beach to sample its
water and test for the presence of fecal coliform bacteria. The Rhode Island water
quality standard for recreation is 50 MPN per 100 ml of salt water and 200 MPN
per 100 ml of fresh water. Results are posted on the department's website, along
with advisories on waterborne illness and beach closures and openings. Public
notification of beach closures is accomplished in several ways, including the use
of color-coded flags at beaches, press releases, and notices on the department
website. The website also supports on-line reporting by the public of suspected
beach-related illnesses.
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Chapter 6—Human Health Impacts of CSOs and SSOs
water treatment and distribution
system and a review of operation and
maintenance practices.
States also implement notification
programs to warn citizens about
human health impacts associated with
recreation at contaminated beaches
and consumption of contaminated
water, fish, or shellfish.
Local Agencies
Local public health agencies, regional
planning authorities, and the owners
and operators of wastewater collection
and treatment facilities have distinct
responsibilities to protect public
health. Working with state oversight,
city and county health departments
often maintain separate divisions
for tracking communicable diseases
and for environmental health. The
communicable disease divisions
of these departments generally
have responsibility for cataloging,
investigating, and reporting cases of
"reportable illness" to the appropriate
state agency. The environmental
health divisions generally have
responsibility for monitoring, analysis,
and posting of recreational waters,
where needed. Owners and operators
of municipal wastewater collection
and treatment facilities have their
own responsibilities, many of which
are stipulated as NPDES permit
requirements, including notifying
the public when SSOs occur and
reporting SSOs to state regulatory and
public health agencies. Communities
with CSSs are required to implement
public notification programs as part of
implementing the NMCs.
6.5.2 Activities to Protect Public
Health from Impacts of CSOs
and SSOs
The principal activities undertaken to
protect the public from the impacts
of CSOs and SSOs can be grouped
into three areas: exposure pathway
monitoring, public notification, and
research. These activities protect
public health by identifying possible
sources of pathogens, reducing public
exposure through notification and
In California, the Orange County Health Care Agency's Ocean Water Protection
Program has a mission to ensure that all public recreational waters meet
bacteriological water quality standards for full body contact recreation activities,
such as swimming, surfing, and diving. Staff collect water samples at approximately
150 locations along the shoreline of Orange County for laboratory analysis for
indicator bacteria. Results of the analysis are reviewed by program specialists who
determine if action needs to be taken to protect the public. Staff are available to
respond on a 24-hour basis to investigate reports of contamination incidents,
including SSOs, affecting Orange County's public beaches.
The Allegheny County Health Department in Pennsylvania implemented a public
notification program designed to warn recreational users of health risks in
CSO-impacted waters in the Pittsburgh area. The program includes publishing
advisories in local newspapers and producing public service announcements on
local television stations to educate the public about health risks associated with
CSO discharges.The department also installed orange warning flags that read"CSO"
at 30 locations near CSO outfalls. The flags are raised to warn recreational users
whenever CSO discharges cause or contribute to elevated bacteria levels.
Local Public Health Activity:
Orange County, CA
Local Public Health Activity:
Allegheny County, PA
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use restriction, when necessary, and
continuing research by public health
experts to better protect public health
in the future. More detail on each
activity is presented below.
Exposure Pathway Monitoring
Exposure pathway monitoring
programs focus on recreational waters,
public drinking water systems, and
fish and shellfish in order to reduce
the risk of human health impacts from
exposure to contaminated water and
food.
Recreational waters are typically
monitored using indicator bacteria to
detect the presence of or the potential
for microbial pathogen contamination.
If the bacteria levels in a given water
sample exceed the state standard for
recreational waters, advisories are
posted or the waterbody is closed. For
example, EPA's 2002 BEACH Program
found that 91 percent of surveyed
beaches had some type of water
quality monitoring program. Though
the frequency of monitoring varied, 63
percent of the beaches were monitored
at least once per week (EPA 2003a).
Public water systems are governed
by National Primary Drinking Water
Standards, also known as primary
standards (EPA2003f). Primary
standards are legally enforceable
standards that protect public health
by limiting the levels of specific
contaminants in drinking water.
To protect the health of those
being served, public water systems
have monitoring requirements.
Contaminants monitored are as
follows (EPA 2002f):
• Microorganisms including
indicator organisms, enteric
viruses, and parasitic protozoa;
• Disinfectants including chlorine,
chlorine dioxide, and chloramine;
• Disinfection byproducts including
bromate, chlorite, haloacetic acids,
and trihalomethanes;
• Inorganic chemicals including
metals, nitrate, and nitrite;
• Organic chemicals including a
broad list of agricultural and
industrial products; and
• Radionuclides.
If monitoring shows the drinking
water is contaminated, the owner or
operator of the public water system
is required to shut down the system
and/or direct the public to take
precautions, such as boiling water.
Fish and shellfish monitoring is
administered jointly by state agencies,
EPA, NOAA, and FDA. Bacteriological
monitoring is used to assess the
potential presence of microbial
pathogens in shellfish harvesting areas.
States, U.S. territories, and authorized
tribes have primary responsibility for
protecting residents from the health
risks of consuming contaminated,
noncommercially caught fish. This
is accomplished by issuing of fish
consumption advisories. These
advisories inform the public when
high concentrations of contaminants
have been found in local fish. They
also include recommendations to
limit or avoid eating certain fish
species from specific waterbodies or
waterbody types.
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Chapter 6—Human Health Impacts of CSOs and SSOs
Public Notification
Public notification programs provide
information to communities regarding
the occurrence of CSO and SSO
events and ongoing efforts to control
discharges.
Public notification programs include
posting temporary or permanent
signs where CSOs and SSOs
occur, coordinating with civic and
environmental organizations, and
distributing fact sheets to the public
and the media. Notices in newspapers
are used to publicize CSO or SSO
discharges in some states. Radio and
television announcements may be
appropriate for CSOs and SSOs with
unusually severe impacts. Distribution
of information on websites is rapidly
gaining wider use. Additional
information on reporting and public
notification is presented in Chapter 8
of this Report to Congress and in the
technology descriptions included as
Appendix L.
Research
Several research activities are expected
to improve the ability of public health
programs to protect humans from
impacts associated with CSOs, SSOs,
and other sources of pollution. Two
examples are provided below.
EPA's National Epidemiological
and Environmental Assessment of
Recreational (NEEAR) Water Study
is intended to develop a better
understanding of water pollution at
beaches, recreational use of beaches,
and public health. As part of the
BEACH Program, this effort seeks to
improve beach monitoring by linking
real-time monitoring results with
meaningful risk-based guidelines.
EPA's Office of Research and
Development has completed the
first in a planned series of studies
to estimate the urban contribution
to the total Cryptosporidium and
Giardia loads to receiving waters (EPA
2003f). It is hoped that the studies will
provide a basis for designing source
water protection programs.
6.6 What Factors Contribute
to Information Gaps in
Identifying and Tracking
Human Health Impacts
from CSOs and SSOs?
Systematic data on human
health impacts as a result of
exposure to CSOs and SSOs
are not readily available. The chief
factors that account for the absence
of direct cause-and-effect data
In 1984, public drinking water for the community surrounding Braun Station,Texas,
was drawn from an artesian well that was not filtered but was chlorinated prior
to distribution. At the time, well water was not routinely sampled in this region
of Texas. Community complaints, however, convinced authorities to begin testing.
Fecal coliform level as high as 2,600/100 ml were measured in untreated well water
samples. Subsequent dye tests indicated that the community's SSS was leaking into
the well water. When attempts to identify the exact site of contamination were not
successful, an alternative water source was provided to the community (D'Antonio
etal. 1985).
Monitoring Identifies SSS
as Source of Drinking Water
Contamination:
Braun Station, TX
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Report to Congress on the Impacts and Control ofCSOs and SSOs
are underreporting of waterborne
disease and the reliance of water
quality monitoring activities on
indicator bacteria instead of microbial
pathogens. Both factors are discussed
below.
6.6.1 Underreporting
Reporting and tracking of outbreaks
of waterborne disease are difficult
under the best circumstances.
Underreporting stems from a number
of causes. CDC's waterborne disease
outbreak surveillance system depends
on states to report outbreaks, and
this reporting is often incomplete.
Existing local systems for tracking
these outbreaks often lack sufficient
information on the cause of the
outbreak to establish whether CSOs
and SSOs are suspected source.
Factors that affect the likelihood that
outbreaks will or will not be detected,
investigated, and reported include
(adapted from CDC 2000):
• Public awareness about illness
symptoms, environmental
conditions that might precipitate
an outbreak, and where to report
symptoms;
• The frequency with which people
experiencing illnesses related to
exposure to contaminated water
seek medical care from the same
provider;
• The adequacy of laboratory
infrastructure to fully investigate
outbreaks;
• The compatability of local
reporting requirements for specific
waterborne diseases with data
tracking systems employed by the
CDC; and
• The integration of state and
local reporting and investigation
protocols for waterborne disease
outbreaks.
Large outbreaks are more likely
to be noticed and reported than
smaller outbreaks. Nevertheless, the
source and exposure pathway of the
1993 Milwaukee cryptosporidiosis
outbreak, the largest documented in
U.S. history, remained unidentified for
more than two weeks (CDC 1996a).
This outbreak, affecting an estimated
403,000 people, was detected only
"when increased sales of antidiarrheal
medicines were observed and reported
to the local public health agency"
(Frost etal. 1995).
6.6.2 Use of Indicator Bacteria
Indicator bacteria are used to
evaluate human health risks from
contaminated water without sampling
for every possible microbial pathogen.
As described in Section 6.1.1,
indicator bacteria are relatively easy
to detect and are used to indicate
the likely presence of fecal-borne
microbial pathogens. There is ongoing
scientific debate regarding the use of
indicators and their ability to predict
human health impacts. Some specific
criticisms of the use of indicator
bacteria are as follows:
• A single indicator organism
may be insufficient to establish
water quality standards. EPAs
current water quality criteria
are targeted toward protecting
people participating in
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Chapter 6—Human Health Impacts of CSOs and SSOs
recreational activities from acute
gastrointestinal illness (EPA
2002g).
• Current bacterial detection
methods are subject to false
positives and false negatives
(Griffin et al. 2001).
• Coliform bacteria can survive and
replicate in waters and soils under
certain environmental conditions.
Their presence is not always due
to recent fecal contamination.
In addition, all current bacteria
indicators are shed by animals.
Their occurrence in the
environment does not always
indicate that human pathogens are
present or that contamination was
due to a human source (Griffin et
al. 2001).
• Indicator bacteria do not directly
indicate the presence of viruses,
which survive longer in marine
waters and have a low infective
dose (Seyfried et al.1984; Freeman
2001; Schvoerer et al. 2001).
Bacteriophages have shown merit
for use as an alternative to indicator
bacteria to identify human health
risks. Specifically, Bacteroides fragilis
bacteriophages have been found to be
more resistant to chlorine than current
indicator bacteria and are thought to
be good indicators of enteric viruses.
Bacteriodes also show potential for
use as an indicator of recent fecal
contamination (Griffin et al. 2001).
Although EPA recognizes the
limitations of indicator bacteria, they
continue to be used to assess potential
human health risk because:
• Indicator bacteria area simple and
inexpensive to measure (Griffin et
al. 2001).
• Studies show that E. coll and
enterococci exhibit a strong
relationship to swimming-
associated gastrointestinal illness
(Fattal et al. 1987; Cheung et al.
1990; EPA 2002g).
• Indicator bacteria are present
where fecal contamination occurs;
they are always present in feces
and at higher levels than most
enteric pathogens (Griffin et al.
2001).
EPA continues to encourage states
and authorized tribes to use E. coli
or enterococcci as the basis of their
water quality criteria for protecting
recreational waters.
6.7 What New Assessment and
Investigative Activities are
Underway?
Several local government agencies
are implementing innovative
programs to identify risks and
to track the types of illness associated
with the pathogens present in CSO
and SSO discharges. Select examples
are provided in this section.
6.7.1 Investigative Activities
Monitoring, modeling, and other
investigative activities are useful
tools in reducing human exposure
to pathogens, identifying waterborne
and foodborne disease outbreaks,
and assessing illness patterns. Some
innovative investigative programs
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intended to reduce human health
impacts and risk are described below.
• In Texas, the Austin-Travis Health
and Human Services Department
has a predictive model for
recreational water quality at the
Barton Springs pool. If the Barton
Creek watershed receives more
than one inch of rainfall, the
pool is closed until monitoring
determines it is safe to reopen
(Staudt2002).
• New York City has an advanced
rainstorm modeling system that
predicts the estimated amount of
fecal matter that will contaminate
beaches after a measurable rainfall.
This information is used to make
decisions on beach closures and is
shared with all area beaches and
neighboring states (Luke 2002).
• Orange County, California,
maintains a passive reporting
system for illnesses from
recreational waters. Between 1998
and 2002, Orange County received
110 ocean and bay bather illness
reports and one illness report
from a freshwater lake (Mazur
2002).
• Boston, Massachusetts, operates
a waterborne surveillance project
that monitors Cryptosporidium
and Giardia illnesses from
drinking water. The program uses
fixed populations within the city
(schools, nursing homes, prisons)
as control groups (Gurba 2002).
• San Diego County, California
Department of Environmental
Health and a group called Surfers
Tired of Pollution conducted a
self-reported ocean illness survey.
Between August 1,1997, and
December 31, 1999, 232 illnesses
were reported. The county plans a
second survey (Clifton 2002).
• The Douglas County, Nebraska
Health Department compares
reported illnesses with a computer
model that provides epidemiologic
analysis for 1- to 10-year periods.
Reported illnesses are compared
with projected baselines and trends
to determine if an outbreak is
occurring (Kurtz 2002).
• New York City has an active
outbreak monitoring procedure.
The Department of Health
tracks reports of giardiasis and
cryptosporidiosis by visiting labs
in New York City on a weekly
basis and making sure all samples
testing positive for the pathogens
are reported. The Department of
Health receives weekly tallies of
diarrheal medicine sold in the area
and has a clinical lab monitoring
system to track the number of
stool samples tested. Finally, the
city monitors hospital emergency
rooms for the number of people
complaining of diarrhea and
vomiting (Seeley 2002).
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Chapter 7
Federal and State Efforts to
Control CSOs and SSOs
The federal and state regulatory
framework for controlling
CSOs and SSOs affects
municipal decision-making on how
to best protect human health and the
environment from these discharges.
This chapter describes the status of
the federal framework used to address
CSOs and SSOs. The discussion on
CSO policies summarizes findings
from the 2001 Report to Congress-
Implementation and Enforcement of
the CSO Control Policy (EPA 200la)
and updates data on the status of
NPDES permit requirements for CSO
control. A brief discussion of current
SSO regulatory efforts follows. This
chapter also describes a number of
state programs to address CSOs and
SSOs, and it presents an overview of
federal compliance assistance and
enforcement efforts related to CSOs
and SSOs.
7.1 What are States and EPA
Regions Doing to Control
CSOs?
On April 19, 1994, EPA
published the CSO Control
Policy that established
objectives for CSO communities and
expectations for NPDES permitting
authorities (59 FR 18688). The CSO
Control Policy also presented elements
of an enforcement and compliance
program to address dry weather CSO
discharges and to enforce NPDES
permit requirements. The four key
principles of the CSO Control Policy
that ensure that CSO controls are cost-
effective and meet the objectives of the
Clean Water Act are:
1. Provide clear levels of control
that would be presumed to
meet appropriate health and
environmental objectives;
In this chapter:
7.1 What are States and
EPA Regions Doing to
Control CSOs?
7.2 What are States and
EPA Regions Doing to
Control SSOs?
7.3 What Programs Have
Been Developed to
Control SSOs?
7.4 What Compliance and
Enforcement Activities
Have Been Undertaken?
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2. Provide sufficient flexibility to
municipalities, especially financially
disadvantaged communities, to
consider the site-specific nature
ofCSOs and to determine the
most cost-effective means of
reducing pollutants and meeting
[Clean Water Act] objectives and
requirements;
3. Allow a phased approach to
implementation ofCSO controls
considering a community's financial
capability; and
4. Provide for review and revision,
as appropriate, of water quality
standards and their implementation
procedures when developing CSO
control plans to reflect the site-
specific wet weather impacts of
CSOs.
Objectives for CSO communities with
NPDES permits are 1) to implement
the NMC and submit documentation
on NMC implementation; and 2) to
develop an LTCP.
7.1.1 Nine Minimum Controls
The NMC are:
1. Proper operation and regular
maintenance programs for the
sewer system and the CSOs
2. Maximum use of the collection
system for storage
3. Review and modification of
pretreatment requirements
to assure CSO impacts are
minimized
5. Prohibition of CSOs during dry
weather
6. Control of solids and floatable
materials in CSOs
7. Pollution prevention
8. Public notification to ensure
that the public receives adequate
notification of CSO occurrences
and CSO impacts
9. Monitoring to effectively
characterize CSO impacts and the
efficacy of CSO controls
Municipalities were expected to
implement the NMC and to submit
appropriate documentation to NPDES
authorities as soon as reasonably
possible, but no later than January 1,
1997. Of the 828 active CSO permits
identified by EPA in July 2004, 94
percent (777 permits) required
implementation of the NMC.
7.1.2 Long-Term Control Plans
In addition to implementing the
NMC, CSO communities are expected
to develop and implement an LTCP
that includes measures to provide for
attainment of water quality standards.
The policy identified nine elements
that an LTCP should include:
• Characterization, monitoring, and
modeling of the CSS
• Public participation
• Consideration of sensitive areas
• Evaluation of alternatives
4. Maximizing flow to the POTW for • Cost/performance considerations
treatment
• Operational plan
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Chapter 7—Federal and State Efforts to Control CSOs and SSOs
• Maximization of treatment at the
POTW treatment plant
• Implementation schedule
• Post-construction compliance
monitoring
LTCP implementation schedules were
expected to include project milestones
and a financing plan for design and
construction of necessary controls as
soon as practicable (EPA 1994a).
In July 2004, EPA confirmed the status
of LTCPs with states and regional
NPDES authorities:
• 86 percent (708 of 828) of permits
required development and
implementation of an LTCP;
• 59 percent (490 of 828) of LTCPs
have been submitted; and
• 35 percent (290 of 828) of LTCPs
have been approved.
More information on the CSO Control
Policy is provided in EPA's 2001 Report
to Congress-Implementation and
Enforcement of the CSO Control Policy.
7.2 What are States and EPA
Regions Doing to Control
SSOs?
SSOs that reach waters of the
United States are point source
discharges, and, like other
point source discharges from SSSs,
are prohibited unless authorized by
an NPDES permit. Moreover, SSOs,
including those that do not reach
waters of the United States, may be
indicative of improper operation and
maintenance of the sewer system,
and thus may violate NPDES permit
conditions.
7.2.1 Application of Standard
Permit Conditions to SSOs
The NPDES regulations establish
standard permit conditions that are
incorporated into all NPDES permits.
Several existing standard permit
conditions have particular application
to SSOs. These include:
Noncompliance Reporting - When
incorporated into a permit, the
standard permit conditions for
noncompliance reporting at 40
CFR 122.41(1)(6) and (7) require
permittees to report any instance
of noncompliance to the NPDES
authority. Unpermitted discharges
from SSSs to waters of the United
States constitute noncompliance,
which the permittee would report
under these provisions.
Recordkeeping - The permit
provisions required by 40 CFR
122.4l(j)(2) require permittees to
retain copies of all reports required
by the permit for a period of at least
three years from the date of the report.
This provision would require retention
of records of noncompliance reports
of SSOs.
Proper Operation and Maintenance
Requirements - The standard permit
conditions at 40 CFR 122.41 (d) and
(e) require proper operation and
maintenance of permitted wastewater
systems and related facilities to achieve
compliance with permit conditions
and that permittees take all reasonable
SSOs can occur at numerous locations in the
sewer system, including at manholes.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 7.1
Summary of Electronic
SSO Data by State
At a minimum, states with elec-
tronic systems for tracking SSOs
compile information on the date,
location, or cause of the overflow.
steps to minimize or prevent any
discharge in violation of the permit
that has a reasonable likelihood of
adversely affecting human health
or the environment. In a permit
for a wastewater treatment facility
and/or a sewer system, these two
standard conditions would require
the permittee to properly operate
and maintain its collection system
as well as take all reasonable steps to
minimize or prevent SSO discharges.
7.2.2 Electronic Tracking of SSOs
A growing number of states have
increased data collection and
tracking efforts for SSOs (excluding
building backups) in recent years.
As part of this report effort, EPA
identified 25 states that track SSO data
electronically. The states and the most
commonly tracked SSO data elements
are listed in Table 7.1.
CA
CO
CT
FL
GA
HI
IN
KS
MA
MD
ME
Ml
MN
NC
ND
NH
NV
OK
Rl
SC
SD
UT
WA
Wl
WY
Date & Start Date End Date Total SSO SSO
Time & Time & Time/ Overflow Location3 Cause
Reported Duration Volume
(gallons)
Response Receiving
Measures Water
Takenb Identified
a May not include exact SSO location point
b May include cleanup activities, volume recovered, and corrective or preventive measures
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SSO Data Publication via the Internet
Maryland and Michigan publish
CSO and SSO data periodically on
the Internet. In Maryland, owners or
operators of an SSS must report any
SSO that results in a discharge of raw
or diluted sewage into the waters of
the state to the Maryland Department
of the Environment (MDE). This
requirement is also applicable to
CSOs and wastewater treatment
plant bypasses. MDE coordinates
reporting requirements with local
health departments. Reports must
include the volume spilled, duration,
start and stop times, name of receiving
waters, cause, corrective action taken,
and information regarding public
notification. CSO and SSO data
reported to MDE can be found at http:
//www.mde.state.md.us/programs/
waterprograms/cso sso.asp.
The Michigan Department of
Environmental Quality (MDEQ)
has broad statutory and regulatory
authority for SSOs under Part 31,
Water Resources Protection, and
Part 41, Sewerage Systems, of the
Natural Resources and Environmental
Protection Act, 1994 PA 451, as
amended. Facilities in Michigan are
required to notify MDEQ within
24 hours of when a CSO or SSO
discharge begins. After the discharge
ends, the facility must submit a
complete report, including the
location and volume of the discharge
as well as the start/end date and time.
MDEQ's CSO and SSO discharge
information web page provides
specific event information on CSOs
and SSOs (http://www.deq.state.mi.us/
csosso/1. In addition to providing
final CSO and SSO reports, MDEQ's
website also displays records of recent
events for which MDEQ has not
yet received a final written report.
Recently, MDEQ produced its first
Combined Sewer Overflow (CSO) and
Sanitary Sewer Overflow (SSO) Report,
which compiled event information
during the period from July 2002
to December 2003. MDEQ expects
that subsequent reports will be made
available on a calendar-year basis.
7.3 What Programs Have Been
Developed to Control
SSOs?
Although there is no national
regulatory program specific
to SSOs, a number of EPA
regions and state agencies have
initiated efforts to address SSOs.
Some agencies require that permittees
assess sewer system condition or
implement specific O&M practices.
Other agencies have implemented
programs requiring sewer system
owners to obtain NPDES permit
coverage, whether or not they operate
a wastewater treatment facility.
The following descriptions are not
intended to be comprehensive, but
represent some innovative approaches
to addressing SSO issues.
7.3.1 EPA Region 4's MOM Program
EPA Region 4's Management,
Operations, and Maintenance
(MOM) Program is implemented in
cooperation with states in the region.
The MOM program encourages
all NPDES permit-holders and
any associated satellite utilities to
participate in a proactive approach to
managing, operating, and maintaining
their sewer system. Utilities that
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implement good MOM Programs
benefit by reducing the likelihood of
Clean Water Act violations, extending
the life of their infrastructure, and
providing better customer service
through steady rates and greater
efficiency. The goal of the MOM
Program is to bring 100 percent of the
POTWs handling domestic wastewater
in Region 4 into compliance with the
"proper operation and maintenance"
provision of their NPDES permits by
2011.
The Region 4 MOM Program
addresses SSO issues in sewer systems
(including satellites) by concentrating
on high priority watersheds. Region
4 uses a Geographic Information
System (CIS) to focus on watersheds
categorized as having existing water
quality problems or assessed as being
vulnerable to stressors (e.g., coastal
and shellfish harvesting areas). Based
in part on recommendations made by
states in the region, Region 4 selects
at least one watershed in each state
for each cycle of the MOM Program.
Region 4 started the second cycle of its
MOM Program in September 2003.
In the selected watersheds, the
operators of all sewer systems are
expected to provide a self-evaluation
report to the region. This report
identifies improvements that can be
made and the schedules necessary to
make those improvements. Region 4
encourages participants to conduct the
self-evaluation within seven months of
receiving the initial requests. To assist
participants with the process, Region 4
provides checklists and other outreach
information. Depending on the
thoroughness of the self-evaluation,
Region 4 may conduct follow-up
inspections and initiate further
discussions regarding the evaluated
programs. Where the permittee does
not conduct an evaluation, Region
4 conducts its own site inspection.
Through voluntary participation in
the program and by self-disclosing any
needed improvements, participants
may be eligible for a reduction in civil
penalties while under a remediation
schedule.
Region 4 expects participants to
develop a plan that addresses the
MOM requirements, which the
region typically includes in a Letter
of Violation (LOV) or an AO. Region
4 recently completed the first round
of LOV inspections and found that
many MOM Program participants
have made significant positive and
productive efforts (e.g., increased
staff, purchased maintenance
equipment, and increased cleaning
frequency) toward the development
and implementation of their MOM
Programs.
7.3.2 Oklahoma - Collection
System Program
The Oklahoma Department of
Environmental Quality (ODEQ)
has actively addressed SSO and
sewer system issues for many years
through its NPDES program.
Program elements include permitting,
compliance, enforcement, and
education/outreach.
Standard NPDES permit language
in Oklahoma requires proper O&M
of the sewer system and reporting
of bypasses and SSOs. A state
construction permit, which is distinct
and different from an NPDES permit,
is required for all new sewer lines
to ensure that the sewer system has
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Chapter 7—Federal and State Efforts to Control CSOs and SSOs
adequate capacity to accommodate
the growth. When a request is made
to ODEQ to expand an SSS, the
capacity of pipes, pumps, and other
system components is evaluated by
ODEQ design and engineering staff
during review of the construction
permit. These requirements encourage
municipalities to have a program in
place to address capacity, management,
operation, and maintenance issues in
their sewer system.
ODEQ evaluates system performance
through compliance evaluation
inspections, complaint and fish kill
investigations, and database record
reviews. Members of the general
public can report SSOs by calling
an ODEQ overflow hotline; ODEQ
investigates all complaints of alleged
SSOs. Oklahoma's criterion for
significant non-compliance due to
SSOs is more than one SSO at the
same location in a 12-month period.
As of 2003, ODEQ has 60-70 active
enforcement orders for SSOs.
ODEQ has maintained an SSO
database and tracking system since
1987. Over the last 15 years, the
annual number of reported SSO
events has decreased by 14 percent,
and the number of enforcement
orders issued annually has decreased
by approximately 25 percent. During
this same period, the number of
municipalities reporting at least one
SSO event has increased by 12 percent.
ODEQ attributes the increase in the
number of systems reporting SSOs
to elevated awareness of SSO issues
by the regulated community and
the public. ODEQ's education and
outreach efforts include operator
certification training, ODEQ-
sponsored seminars, and staff
presentations to municipal leagues,
rural water associations, regulated
communities, and other affected
groups.
7.3.3 California - Record Keeping
and Reporting of Events
Some of California's Regional Water
Quality Control Boards (RWQCBs)
use Waste Discharge Requirements
(WDR), a form of discharge permit,
to address SSOs. These orders
prohibit all discharges of wastewater
from a sewer system upstream of a
wastewater treatment plant. Priorities
in California are to address beach
closures linked to SSOs, such as those
occurring in Orange County, San
Diego, and Los Angeles.
The RWQCB Orders require proper
O&M, sewer system management
plans, capacity evaluations, and FOG
programs. For example, in May 1996,
the San Diego RWQCB adopted Order
No. 96-04 prohibiting SSOs. This
order was adopted as a mechanism
to achieve a reduction in the number
and volume of SSOs and to protect
water quality, the environment,
and public health. Order No. 96-04
also brings satellite sewer systems
under a regulatory framework. The
order regulates 48 cities and special
districts in the San Diego area
that own and operate SSSs. It also
requires a monitoring and reporting
program with specific SSO reporting
procedures.
In addition, California has a statewide
regulation requiring utilities to report
SSOs greater than or equal to 1,000
gallons and all SSOs that reach surface
waters. Reports must be made within
Advisory and closing signs are posted at
beaches throughout Orange County, CA, to
alert beachgoers of potential dangers, from
elevated bacterial levels.
Photo: OCHA Ocean Water Protection Program.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
24 hours of becoming aware of the
spill and followed up with a written
report within five days. The RWQCBs
have issued several large penalty
orders for SSOs (generally one dollar
per gallon spilled).
7.3.4 North Carolina - Collection
System Permitting
In 1999, the North Carolina General
Assembly ratified HB 1160 (1999
NC Sessions Laws Chapter 329),
a bill that requires SSSs to obtain
a comprehensive permit separate
from the NPDES permit obtained
by wastewater treatment facilities.
The North Carolina Department
of Environment and Natural
Resources (NCDENR) administers
this permitting program through the
Non-Discharge Permitting Branch in
coordination with the Enforcement
Group. The focus of the NCDENR
program is proactive, preventive O&M
of sewer systems.
NCDENR collection system permits
contain five principal sections:
performance standards, O&M,
inspections, record keeping, and
general conditions. Conditions
are included for grease control,
planned reinvestment in the SSS
through a capital improvement
plan, alarms for pump stations,
spare parts, inspections, cleaning,
mapping, observation, and preventive
maintenance. The permits also include
public notification and other reporting
requirements. NCDENR has provided
guidance for reporting SSOs that
includes a standardized calculation for
estimating the volume of SSOs when
they occur.
NCDENR is using a phased approach
to permit all SSSs over a five-year
period (20 percent/year). This
program incorporates a number of
older satellite systems that have never
been permitted. The first round of
permits was issued in 2001. Sewer
systems that fail to meet the standard
permit conditions may be subject to
enforcement action by NCDENR. The
1999 legislation dramatically increased
the potential civil penalties that may
be assessed against the municipality
for unauthorized discharges (G.S. 143-
215.6A).
7.4 What Compliance and
Enforcement Activities
Have Been Undertaken?
The goal of EPA's water
compliance and enforcement
program is to ensure
compliance with the Clean Water Act.
EPA's compliance and enforcement
program has five major objectives:
• Provide compliance assistance
tools and information to the
regulated community;
• Identify instances of
noncompliance;
• Return violators to compliance;
• Recover any economic advantage
obtained by the violator's
noncompliance; and
• Deter other regulated facilities
from noncompliance.
EPA established "wet weather"
(i.e., CSOs, SSOs, storm water,
and concentrated animal feeding
operations) as a national enforcement
priority for FY 2002 and FY 2003.
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Chapter 7—Federal and State Efforts to Control CSOs and SSOs
The compliance and enforcement
policies and strategies used to address
CSOs and SSOs are discussed in the
following subsections. In addition,
a summary of related enforcement
actions as of October 2003 is
presented.
7.4.1 National Municipal Policy on
POTWs
EPA's 1984 National Municipal
Policy on Publicly-Owned Treatment
Works (NMP) provided an impetus
for control of all discharges from
municipal sewer systems, treated or
otherwise (EPA 1984b). The NMP
encouraged a collaborative effort
between EPA and states in addressing
compliance with the Clean Water Act
at POTWs. The NMP focused EPA's
compliance efforts on three types
of POTWs: those that had received
federal funding and were out of
compliance, and all major POTWs,
and minor POTWs that discharged
to impaired waters. The NMP
recommended that each EPA region
draft a strategy to bring POTWs into
compliance with the Clean Water Act.
The NMP was intended to facilitate
compliance at all POTWs by July 1,
1988. While the main focus of the
NMP was to ensure that POTWs
complied with secondary treatment
and water-quality based NPDES
requirements, many enforcement
actions brought under the NMP also
addressed improvements to sewer
systems.
7.4.2 Enforcement Management
System
EPA's national enforcement guidance,
Enforcement Management System,
recommends using a scaled response
to noncompliance considering such
factors as the nature, frequency, and
severity of the violation; potential
harm to the environment and public
health; and the compliance history
of the facility. Chapter X: Setting
Priorities for Addressing Discharges
From Separate Sanitary Sewers includes
a list of priorities for dealing with
SSOs to ensure that enforcement
resources are used in ways that result
in maximum environmental and
public health benefit (EPA 1996c). The
complete text of Chapter X is provided
in Appendix A. EPA's enforcement
response guidelines range from
informal actions such as telephone
calls or warning letters to formal
administrative or civil judicial actions.
7.4.3 Compliance and Enforcement
Strategy (2000)
On April 27, 2000, EPA issued the
Compliance and Enforcement Strategy
Addressing Combined Sewer Overflows
and Sanitary Sewer Overflows (EPA
2000b). This strategy was designed to
ensure that CSO and SSO violations
are properly addressed by promoting
the enforcement and compliance
assistance components of the
following:
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Report to Congress on the Impacts and Control ofCSOs and SSOs
• CSO Control Policy (EPA 1994a);
• Joint Office of Enforcement
and Compliance Assistance/
Office of Water memorandum
"Enforcement Efforts Addressing
Sanitary Sewer Overflows" (March
7, 1995); and
• Chapter X of the Enforcement
Management System (EPA 1996c).
The strategy also supports the
Memorandum of Agreement for
EPA's regional office performance
expectations, EPA's Clean Water Action
Plan, and EPA's Strategic Plan.
The strategy calls for each EPA
region to develop compliance and
enforcement plans addressing CSOs
and SSOs. The plans should include:
• A systematic approach to address
wet weather violations through
compliance assistance;
• The identification of compliance
and enforcement targets; and
• Details on NPDES state
participation, including tracking
of state CSO and SSO compliance
and enforcement activities.
Specifically, the SSO response plan
should describe the process and
criteria that the region and states
use to identify priority systems each
year and include an inventory of SSO
violations (EPA 200la). As of August
2003, all regions except Region 4 had
developed and begun implementation
of their strategies.
7.4.4 Compliance Assistance
EPA has developed a number of tools
for tracking and sharing compliance
assistance and other information for
addressing CSOs and SSOs internally
among EPA staff and externally
with states, local governments, and
others. Several of these tools have
specific references and guidance for
implementing the NMC; developing
an LTCP; and implementing capacity,
management, operations, and
maintenance (CMOM) and asset
management approaches to eliminate
or reduce SSOs. Examples include:
Local Government Environmental
Assistance Network (LGEAN) - The
EPA-sponsored compliance assistance
center for local municipal governments
provides environmental management,
planning, and wet weather regulatory
and legislative information for elected
and appointed officials, managers, and
staff (http://www.lgean.org).
National Environmental Compliance
Assistance Clearinghouse - This
clearinghouse provides compliance
assistance tools, contacts, and other
wet weather (including CSO-specific)
resources available from EPA as well as
other public and private compliance
assistance providers
(http://www.epa.gov/clearinghouse).
Statistically Valid Non-Compliance
Study - EPA's Office of Enforcement
and Compliance Assistance (OECA)
completed the Statistically Valid
Non-Compliance Study to assess
compliance with NMC requirements.
EPA has a goal of ensuring that all
CSO communities have an enforceable
mechanism requiring implementation
of the NMC, are in compliance with
those controls, and, if needed, have
developed and are implementing an
LTCP. Determination of the current
compliance rate of CSO communities
with the NMC was an EPA priority in
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Chapter 7—Federal and State Efforts to Control CSOs and SSOs
FY 2002. OECA found the national
compliance rate with the NMC was
39 percent. OECA plans to repeat the
assessment of NMC compliance in
FY 2004. The new analysis will also
assess the status of CSO communities
with respect to development and
implementation of LTCPs.
Permit Compliance System - EPA is
working to modernize PCS. When
complete, this database of NPDES
point source dischargers will track
information specifically related to
CSOs and SSOs.
CSO Implementation Guidance - EPA
has released eight guidance documents
to assist in implementation of the
CSO Control Policy. The eight
guidance documents explain technical,
financial, and permitting issues related
to implementation of the policy and
are as follows:
• Combined Sewer Overflows
Guidance for Funding Options
(EPA 1995a)
• Combined Sewer Overflows
Guidance for Long-Term Control
Plans (EPA 1995b)
• Combined Sewer Overflows
Guidance for Nine Minimum
Control Measures (EPA 1995c)
• Combined Sewer Overflows
Guidance for Permit Writers (EPA
1995d)
• Combined Sewer Overflows
Screening and Ranking Guidance
(EPA 1995e)
• Combined Sewer Overflows
Guidance for Financial Capability
Assessment and Schedule
Development (EPA 1997c)
• Combined Sewer Overflows
Guidance for Monitoring and
Modeling (EPA 1999&)
• Guidance: Coordinating Combined
Sewer Overflow (CSO) Long-Term
Planning with Water Quality
Standards Reviews (EPA 200Ib)
7.4.5 Summary of Enforcement
Activities
Federal and state enforcement actions
concluded against municipalities for
CSO- and SSO-related violations
are summarized below. Individual
enforcement actions are listed in
Appendix K.
Summary of Federal Judicial Actions
Thirty-six federal judicial enforcement
actions have been concluded against
municipalities in Regions 1-5 as a
result of CSO violations. The relevant
state served as a co-plaintiff with the
EPA region in most cases. Since 1995,
26 judicial actions have been brought
against municipalities in Regions 1 -6
and Region 9 for SSO violations. As in
the CSO judicial actions, many of the
SSO actions were initiated by the EPA
region in cooperation with the state.
Summary of Federal Administrative
Actions
Sixty Federal AOs have been issued for
CSO violations in Regions 1, 3, and 5
since 1987. Two CSO Administrative
Penalty Orders (APOs) were issued
to municipalities in Massachusetts.
Between 1994 and 2003, 78 AOs were
issued to municipalities in Regions
1-7 and Region 10 for SSO violations.
Twelve SSO APOs were issued during
the same period.
Guidance For Monitoring
And Modeling
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Summary of State Judicial Actions state-initiated administrative actions
EPA's review of available state-initiated for CSO violations is included in
CSO enforcement cases yielded 16 Appendix K. EPA's review of available
CSO civil judicial actions. EPA's review state-initiated enforcement cases
of available state-initiated enforcement found 597 administrative actions
cases found six judicial actions against against municipalities for SSO
municipalities for SSO violations. violations. In addition, EPA identified
18 CSO administrative penalty orders
c r c. and 137 SSO administrative penalty
Summary of State Administrative ;
Actions orders issued by states.
A number of states have initiated
administrative enforcement actions
to address CSO violations. A list of 53
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Chapter 8
Technologies Used to Reduce the
Impacts of CSOs and SSOs
Since the enactment of the Clean
Water Act in 1972, federal,
state, and local governments
have made substantial investments
in the construction, operation, and
maintenance of wastewater collection
and treatment systems. Municipalities
employ a wide variety of technologies
and operating practices to maintain
existing infrastructure, minimize the
introduction of unnecessary waste
and flow into the sewer system,
increase capture and treatment of
wet weather flows reaching the sewer
system, and minimize the impact of
any subsequent discharges on the
environment and human health.
For the purposes of this Report to
Congress, technologies used to control
CSOs and SSOs are grouped into five
broad categories:
• Operation and maintenance
practices
• Collection system controls
• Storage facilities
• Treatment technologies
• Low-impact development
techniques
Most technologies and operating
practices are designed to reduce, not
eliminate, the discharge of pollutants
and attendant impacts because it is
generally not feasible to eliminate all
discharges.
This chapter provides an overview of
technologies used to control CSOs and
SSOs. In addition, the chapter also
discusses:
• Factors that can influence the
effectiveness of specific technology
applications;
• Combinations of technologies
that have proven more effective
than application of individual
technologies; and
• Emerging technologies that show
promise in controlling CSOs and
SSOs.
A complete set of detailed technology
descriptions is contained in Appendix
L of this report.
In this chapter:
8.1 What Technologies are
Commonly Used to Control
CSOs and SSOs?
8.2 How Do CSO and SSO
Controls Differ?
8.3 What Technology
Combinations are
Effective?
8.4 What New Technologies
for CSO and SSO Control
are Emerging?
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Report to Congress on the Impacts and Control ofCSOs and SSOs
8.1 What Technologies are
Commonly Used to Control
CSOs and SSOs?
Municipalities have used
numerous technologies
and operational practices
to reduce the volume, frequency,
and impacts of CSO and SSO
events. The performance and cost-
effectiveness of these technologies
is often related to a number of site-
specific factors. Technologies deemed
highly effective in one location may
prove inappropriate in another.
Specific factors that may influence
the selection of a given technology
include:
• Current condition of the sewer
system;
• Characteristics of wet weather
flows (e.g., peak flow rate, flow
volume, concentration of key
pollutants, frequency and duration
of wet weather events);
• Hydraulic and pollutant loading
to a particular facility;
• Climate, including seasonal
variations in temperature and
rainfall patterns;
• Implementation requirements
(e.g., land or space constraints,
surrounding neighborhood, noise,
disruption, etc.); and
• Maintenance requirements.
This section describes 23 of the
technologies and operational practices
most commonly used to control CSOs
and SSOs, including considerations
for determining the applicability
of different controls for individual
locations. More detailed information
on each technology, including cost
and performance considerations,
is presented in the technology
descriptions provided in Appendix L
of this report.
8.1.1 Operation and
Maintenance Practices
Over time, CSSs and SSSs can
deteriorate structurally or become
clogged by FOG and other
obstructions introduced into the
sewer system. Left uncorrected,
these conditions can result in dry
weather CSOs and SSOs. Further,
these conditions often are exacerbated
during wet weather when the capacity
of sewer systems and treatment
facilities can be severely taxed.
The objective of O&M practices is
to ensure the efficient and effective
collection and treatment of wastewater
and to minimize the volume and
frequency of CSO and SSO discharges.
For purposes of this report, O&M
practices include activities designed
to ensure that sewer systems
function as designed and strategies
that rely on public education and
participation. The specific O&M
practices considered for this report are
summarized in Table 8.1 and include:
• Inspecting and testing of the sewer
system to track condition and
identify potential problems;
• Cleaning or flushing deposits of
sludge, sediment, debris, and FOG
from the sewer system;
• Working with customers to reduce
pollutant loads delivered to the
sewer system; and
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Chapters—Technologies Used To Reduce the Impacts of CSOsand SSOs
• Establishing procedures for
notifying the public in the event
of a CSO or SSO.
Sewer Inspection and Testing
Sewer inspection is used to determine
the condition of sewer lines and
identify potential problems. Common
sewer system inspection techniques
can be grouped into two categories:
manual and remote. Manual
inspection techniques, such as visual
inspection and lamping, are simple
and typically limited to the first few
feet of pipe upstream and downstream
of each accessible manhole. Remote
inspection techniques, such as closed-
circuit television and sonar, use units
that are either self-propelled or pulled
through the sewer line to capture
information on sewer condition.
In general, sewer testing techniques
are used to identify leaks that allow
unwanted infiltration into the sewer
system and to determine the location
of direct connections of storm water
sources to the sewer system (e.g., roof
leaders, area drains, basement sump
pumps). Sewer testing techniques fall
into three categories:
• Air testing
• Hydrostatic testing
• Smoke testing
Technology
Sewer inspection and testing
Sewer cleaning
Pollution prevention
Air testing and hydrostatic testing
identify cracks and other defects in the
sewer system that might allow storm
water or groundwater to infiltrate.
Smoke testing is used to identify
connections that allow direct storm
water inflow to the sewer system.
Sewer Cleaning
Sewer cleaning and flushing
techniques remove blockages caused
by solids, FOG, and root intrusion.
Sewer cleaning techniques are
particularly important because
blockages are the leading cause of
SSO events (see Section 4.7). Cleaning
techniques fall into three categories:
• Hydraulic
• Mechanical
• Chemical
Hydraulic cleaning techniques employ
the cleansing action of high velocity
water. Cleansing velocities are achieved
by allowing water pressure to build
in a sewer line or by using a pump to
produce water pressure. In general,
hydraulic cleaning techniques tend
to be simpler and more cost-effective
in removing deposited solids when
compared to other sewer cleaning
techniques (CSU 2001). Alternatively,
mechanical cleaning methods rely on
a scraping, cutting, pulling, or pushing
action to remove obstructions from
sewer lines. Mechanical techniques
Type of System Pollutants/Problems Addressed
CSS, SSS
CSS, SSS
Table 8.1
Summary of Operation
and Maintenance
Practices
The objective of O&M practices
is to ensure that sewer systems
function as designed and convey
the maximum amount of flow
practicable to a treatment facility.
BOD5,TSS, nutrients, toxics, pathogens,
floatables,FOG
CSS,SSS
Water quality monitoring and CSS, SSS
public notification
Nutrients, toxics, FOG
BOD5,TSS, nutrients, toxics, pathogens
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Report to Congress on the Impacts and Control ofCSOs and SSOs
are typically used in areas where the
volume, size, weight, or type of debris
limits the effectiveness of hydraulic
techniques. Chemicals can be used to
control roots, grease, odors, concrete
corrosion, rodents, and insects (CSU
2001). Chemicals can be helpful aids
for cleaning and maintaining sewers,
though chemical applications often are
localized or coupled with a hydraulic
or mechanical technique.
Pollution Prevention
Pollution prevention is defined as
any practice that reduces the amount
of pollutants, hazardous substances,
or contaminants entering the waste
stream, which in turn would mean
fewer pollutants in potential CSO or
SSO discharges (EPA 2002b). Pollution
prevention practices most often take
the form of simple, individual actions
that reduce the pollutants generated
by a particular process. Therefore,
pollution prevention programs
must be implemented with broad
participation to realize a discernible
reduction in pollutant loads
discharged to sewer systems. Public
education is a key component of
most pollution prevention activities.
Education programs are most
successful when tailored to a specific
audience (i.e., residential, institutional,
or commercial).
Pollution prevention activities usually
focus on best management practices
for both commercial/industrial
facilities and residential customers to
reduce pollutant loads discharged to
sewer systems. Pollutants of concern
include FOG, household hazardous
wastes, fertilizers, pesticides, and
herbicides. In particular, the effective
management of FOG has recently
received attention as an important
technique for controlling SSOs.
As reported in Chapter 4, FOG is
the leading cause of blockages in the
United States, and blockages account
for nearly half of all SSO discharges.
The best way to prevent blockages
due to FOG is to keep FOG out of the
sewer system. Many municipalities
have adopted regulations controlling
the introduction of FOG into the
sewer system. Education programs
are important in making residents
and owners of institutional and
commercial establishments, especially
restaurants, aware of their role in
managing FOG. Grease trap design
and maintenance is a vital part of any
Sewer Cleaning:
Sioux Falls, SD
The SSS for the City of Sioux Falls, South Dakota, consists of 578 miles of pipes
ranging in size from six to 66 inches in diameter. The sewer system is divided
into 20 drainage basins, and the maintenance program provides that the entire
system is cleaned once every three years. Maintenance records are stored in a
database that generates work orders by date and drainage basin. Sanitary sewer
maintenance includes high pressure jetting, vacuuming to remove loosened debris,
and mechanical and chemical root control. Closed circuit television (CCTV) is used
to identify trouble spots.This results in more frequent cleaning than the scheduled
three-year interval requires in problem areas. In 2001,372 miles of sewer (64 percent
of the sewer system) were televised and cleaned. The cost for these activities was
approximately $236 per inch-diameter mile of pipe. Assuming an average pipe
diameter of ten inches, inspection and cleaning costs about $0.45 per linear foot.
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education program for commercial
and institutional customers.
Water Quality Monitoring and Public
Notification
Water quality monitoring and public
notification practices are important in
minimizing potential human health
impacts that can result from exposure
to pathogens and other pollutants
in CSO and SSO discharges. Water
quality monitoring is used routinely
to verify the suitability of a particular
waterbody for fishing, swimming, or as
a drinking water source; and to identify
whether a specific CSO or SSO event
has impaired water quality. Public
notification programs are intended to
communicate water quality monitoring
results, general information regarding
the occurrence of CSO and SSO events,
and municipal efforts to control
discharges. Public notification program
activities include posting temporary
or permanent signs where CSOs and
SSOs occur, coordinating with civic
and environmental organizations, and
distributing fact sheets to the public
and the media. Monitoring and public
notification programs should be a
high priority at beaches or recreational
areas, whether directly or indirectly
affected by CSOs and SSOs, due to the
increased risk of human contact with
pollutants and pathogens (EPA 2002i).
When developing a monitoring and
public notification program, the
lag time that often occurs between
collecting water samples and providing
the public with results is important
to consider. This lag is due to the
time required (from 24 to 72 hours)
to test for the presence of bacterial
indicators of contamination. During
this time, pathogen levels, weather,
and water conditions, and related
environmental or human health risks
may change. This means that decisions
regarding beach and recreational water
postings, closings, and re-openings
using bacterial indicators often reflect
conditions as they were one to three
days earlier (EPA 2002i). Further,
contaminants may no longer be
present once test results are available,
and safe beaches may be closed
needlessly. As described in Chapter
6, some communities and beaches
have procedures to close beaches
proactively when a CSO-producing
rainfall event has occurred.
8.1.2 Collection System Controls
Collection system controls are
designed to maximize the capacity of
the sewer system to transport or store
domestic, commercial, and industrial
wastewater. This is accomplished by
adjusting hydraulic control points
to maximize available sewer system
capacity and by implementing
programs and practices to minimize
the volume of I/I that enters the sewer
system. The specific collection system
controls considered for this report are
summarized in Table 8.2, and include:
• Maximizing flow to the treatment
plant;
• Installing a network of flow
monitors to better understand and
manage the response of the sewer
system to wet weather events;
• Identifying and eliminating direct
connections of storm water to the
sewer system (inflow);
• Separating combined sewer
systems into storm and sanitary
systems; and
This CSO notification sign is
posted along Brandywine Creek in
Wilmington, Delaware, as part of a
public notification program. It warns
swimmers of the presence of a CSO
outfall and advises that raw sewage
and bacteria may be present after a
storm.
Photo: City ofWilmington Department of Public Works
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 8.2
Summary of Collection
System Controls
Collection system controls are
designed to maximize the use
of existing sewers to collect and
convey wastewater to a treatment
facility.
• Rehabilitating sewer system
components.
Collection system controls are
designed to maintain the structural
integrity of CSSs and SSSs, and to
maximize available capacity for
transporting wastewater to a treatment
plant. Some municipalities have found
combining various rehabilitation
techniques with inflow reduction
activities to be a cost-effective and
successful means of controlling SSOs.
Other municipalities have found
that implementing one or more of
these collection system controls in
conjunction with storage facilities or
treatment a cost-effective CSO control.
Maximizing Flow
EPA encourages plants serving CSSs
and SSSs to minimize CSOs and SSOs
during wet weather events by using
existing infrastructure to maximize
flow to the treatment plant (EPA
1994a; NYSDEC 1997). Maximizing
flow to the treatment plant often
involves simple and low-cost measures,
including:
• Capacity evaluations of the sewer
system and pumping stations to
determine the maximum amount
of flow that can be transported
(Sherrill et al. 1997).
• Sewer investigations to identify
bottlenecks or constrictions that
limit flow in specific areas and
prevent downstream treatment
capacity from being fully utilized.
• Targeted O&M activities to
address structural deterioration,
obstructions due to FOG and
sediment buildup and excessive
I/I.
The benefits of maximizing wet
weather flows to the existing treatment
plant depend on the ability of the
plant to accept and provide treatment
to increased flows. The consequences
of mismanaging extreme flows at
the treatment plant include flooding
the treatment plant and washing
out biological treatment processes,
which can result in reduced treatment
capacity and efficiency at the plant for
extended periods of time. Likewise,
changes in sewer system operation
without a careful analysis of transport
capacity can result in increased
building backups or street flooding.
Technology
Maximizing flow to the
treatment plant
Monitoring and real-time
control
Inflow reduction
Sewer separation
Sewer rehabilitation
Service lateral
rehabilitation
Manhole rehabilitation
Type of
System
CSS,SSS
CSS,SSS
CSS,SSS
CSS
CSS,SSS
css,sss
sss
Pollutants/Problems
Controlled
6005, TSS, nutrients, toxics, pathogens,
floa tables
Peak wet weather flow rate
I/I, peak wet weather flow rate
I/I, peak wet weather flow rate
I/I, peak wet weather flow rate
I/I, peak wet weather flow rate
I/I, peak wet weather flow rate
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Chapters—Technologies Used To Reduce the Impacts of CSOsand SSOs
Monitoring and Real-Time Control
Basic flow monitoring is an important
component of O&M programs in
most systems. Effective monitoring
programs enable evaluations
of diurnal and day-to-day flow
patterns as well as I/I in a sewer
system. Moreover, monitoring is
extremely valuable in establishing
maintenance schedules, developing
hydraulic models, planning related to
capital improvements, and ensuring
regulatory compliance.
Enhanced monitoring programs in
SSSs and real-time control systems
in CSSs use more complex flow
monitoring networks to optimize
sewer system performance. In SSSs,
enhanced monitoring information
can be used to identify blockages or
capacity-constrained areas of the
sewer system where wet weather SSOs
are likely to occur. In CSSs, integration
of real-time flow, regulator, pump, and
storage information can be used to
maximize use of storage capabilities
and to maximize flow to the treatment
plant.
Inflow Reduction
Inflow is the entry of extraneous
storm water into a sewer system from
sources other than infiltration, such
as basement drains, roof leaders,
manholes, and storm drains. Inflow
reduction refers to the identification
and elimination of these sources to
reduce the amount of storm water
that enters CSSs and SSSs. By reducing
the volume of storm water entering
the sewer system, more conveyance,
storage, and treatment capacity is
available for sanitary flows during
wet weather. This, in turn, aids in
reducing the frequency, volume, and
duration of wet weather CSO and SSO
events. Common inflow reduction
techniques include the disconnection
of roof leaders, redirection of area and
foundation drains and basement sump
pumps, and elimination of cross-
connections between separate sanitary
and storm water systems (EPA 1999f).
Inflow reduction techniques can be
an efficient way to improve sewer
system performance, especially when
the diverted storm water can be
conveniently directed either to surface
waters or to open land for infiltration
or detention (EPA 1999f). For SSSs,
inflow reduction techniques usually
target specific areas with chronic SSOs.
For CSSs, these techniques are applied
more broadly to minimize the size of
structural controls.
Sewer Separation
Sewer separation is the practice of
separating the single-pipe CSS into
separate systems for sanitary and
storm water flows. Full separation
can be applied on a system-wide basis
to eliminate the CSS. This approach
is most practical for communities
with small areas served by combined
sewers. Separation of select areas
within a CSS is widely used by large
and small CSO communities as an
element of a broader LTCP.
Sewer separation can be highly
effective in controlling the discharge
of untreated wastewater. Under ideal
circumstances, full separation can
eliminate CSO discharges. A survey
of readily available information in
NPDES files indicates that sewer
separation is the most widely used
CSO control, accounting for half of
CSO control measures found in LTCP
The Milwaukee Metropolitan Sewer District
uses real-time data to monitor the flow in its
sewer system tunnels and pipes.
Photo: Milwaukee Metropolitan Sewer District
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Monitoring and Real-
Time Control:
Seattle, WA
The direct connection of roof leaders (shown
above) and other inflow sources can limit
sewer system capacity for conveying sanitary
wastewater during wet weather.
Photo: Milwaukee Metropolitan Sewer District
Seattle was one of the first U.S. communities to implement and operate an advanced
real-time control system to control CSO discharges.Seattle's system,called Computer
Augmented Treatment and Disposal (CATAD), began operating in 1971. In the late
1980s, treatment plant computer hardware was upgraded, remote telemetry units
at regulators and pump stations were replaced by programmable logic controllers,
and graphical displays used by operators were improved. Based on the success of
the CATAD technology, Seattle implemented a new, predictive real-time control
system that went on-line in early 1992. Rainfall prediction capabilities that utilize
rain gage data and a runoff model were added. A global optimization program
was introduced that computed optimal flow and corresponding gate position for
each regulator within the CSS. A distributed network allows control decisions to be
implemented without operator intervention.The computer program uses real-time
operation and system performance data to predict or forecast conditions through
the system and directs control elements to utilize in-line storage during periods of
high flow.
documentation (EPA 200la). This
suggests that many CSO communities
identify portions of their CSS in which
separation is a cost-effective CSO
control. Under these circumstances,
separation is often implemented in
conjunction with other public works
projects, including road work and
redevelopment. Sewer separation on
its own, however, does not always lead
to an overall reduction in pollution
or the attainment of water quality
standards. Storm water discharges
from the newly created separate
storm sewer system can contain
substantial pollutant loads that may
cause or contribute to water quality
problems. Implementation of storm
water controls may be necessary
following sewer separation in order to
achieve the pollutant load reductions
necessary for attainment of water
quality standards.
In practice, there are three distinct
approaches to sewer separation:
• Full separation wherein
new sanitary sewer lines are
constructed with the existing CSS
becoming a storm sewer system.
This is probably the most widely
used form of separation.
• Full separation wherein an
entirely new storm sewer system
is constructed with the existing
CSS remaining as a sanitary sewer
system. This form of separation
is not often used because the
capacity of the existing CSS was
designed to accommodate storm
water runoff, which is more than
what is required to accommodate
sanitary flows.
• Partial separation wherein a new
storm sewer system is constructed
for street drainage, but roof
leaders and basement sump
pumps remain connected to the
existing CSS.
Sewer Rehabilitation/Replacement
The structural integrity of many sewer
system components deteriorates with
use and age. This gradual breakdown
allows more groundwater and storm
water to infiltrate into the sewer
system. This increases the hydraulic
load and, in turn, reduces the system's
ability to convey all flows to the
treatment plant. During wet weather
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Chapters—Technologies Used To Reduce the Impacts of CSOsand SSOs
events, excessive infiltration can cause
or contribute to CSOs and SSOs.
Sewer rehabilitation/replacement
restores and maintains the structural
integrity of the sewer system, in
part by reducing or mitigating the
effects of infiltration. Common
sewer rehabilitation and replacement
techniques include:
• Removal and replacement of
defective lines;
• Trenchless technologies that use
the existing sewer to support a
new pipe or line;
• Shotcrete, wherein a mixture of
cement, sand, and water is applied
to sewer walls; and
• Grouting and epoxy injections to
seal leaks and cracks.
Inspecting and evaluating current
sewer condition is necessary before
a sewer rehabilitation technique
is chosen, as the condition of the
sewer may favor specific techniques.
Removing and replacing defective
lines is the most commonly used
rehabilitation technique when the
sewer line is structurally deficient
(CSU 2001). Complete replacement is
often the most effective rehabilitation
method in areas where increased
conveyance capacity is needed (WEF
1999a).
Trenchless technologies are especially
well-suited to urban areas where the
traffic disruption associated with
large-scale excavation projects can be a
significant obstacle to a project (WEF
1999a). In addition, many sewers
are located near other underground
utilities in urban areas, which can
complicate traditional dig-and-replace
methods; trenchless technologies avoid
underground utilities by using the
existing sewer to support a new pipe
or line. Trenchless technologies include
sliplining, cured-in-place pipe (CIPP),
modified cross-section liners, and pipe
bursting.
Shotcrete, a non-invasive rehabilitation
method, is often used to rehabilitate
sewers with major structural problems.
Shotcrete, however, can be used only
in pipe with a diameter of at least 36
inches (CSU 2001).
Grouting and epoxy injections are
most appropriate when the sewer is
structurally stable but experiencing
infiltration.
Service Lateral Rehabilitation
Private building service laterals are
the pipes that convey wastewater from
individual buildings, including houses,
to the municipal sewer system. Recent
studies indicate that a significant
component of the infiltration in any
sewer system is the result of service
lateral defects that contribute varying
quantities of I/I (WEF 1999b). During
wet weather events, excessive I/I can
cause or contribute to CSOs and SSOs.
In general, service lateral rehabilitation
techniques are similar to those used for
larger diameter sewers and include:
• Removing and replacing defective
service laterals;
• Applying trenchless technologies
that use the existing service lateral
to support a new pipe or liner; and
• Using grouting and epoxy
injections to seal leaks and cracks.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Assigning responsibility for the repair
or replacement of service laterals is
often cited as the biggest obstacle to
correcting known defects. Notably,
several studies highlighted significant
problems in gaining access to private
property until the municipality
assumed full financial responsibility
for the repair or replacement costs
(Paulson et al. 1984; Curtis and
Krustsch 1995).
Manhole Rehabilitation
Manholes must be maintained
and kept in working condition.
Structurally defective manholes can
be a significant source of I/I that
otherwise would not enter an SSS.
Damage to manhole covers and rims
often occurs during road work, and
it can allow storm water runoff from
roads and sidewalks to flow directly
into the sewer system. Further, cracks
and openings in the sidewalk and base
of the manhole can allow groundwater
and storm water to infiltrate into the
sewer system. Manhole rehabilitation
can reduce I/I, restore the structural
integrity of the manhole, and
preserve SSS capacity for transporting
wastewater. Common manhole
rehabilitation methods include (ASCE
1997):
• Sealing pick holes in the manhole
cover and installing gaskets
between the manhole cover and
frame to eliminate storm water
inflow;
• Implementing spot repairs with
chemical grout or fast-drying
cement to patch defects in
manhole sidewalk or bases;
• Coating systems to rebuild
structural integrity and protect
concrete, steel, and masonry
manhole structures against
deterioration;
Service Lateral
Rehabilitation:
Montgomery, AL
In Alabama, the Montgomery Water Works and Sanitary Sewer Board (MWWSSB)
evaluated nearly 2.2 million linear feet of its sewer system, identifying 3,394 defects.
Eighty-five percent of these defects were in service laterals; 97 percent of lateral
defects identified have been repaired.
Lateral repairs necessary within the city street right-of-way are made by MWWSSB
with consent and release of liability from the property owner. MWWSSB replaces
missing clean-out covers for a minimal cost with written permission from the
property owner.The property owners are responsible for the cost of all lateral repair
and replacement on their property.
Property owners initially received a 60-day notice of lateral repair requirements.
Another 10-day notice was sent if the property failed to respond to the initial
notice. Finally, if the property owner failed to respond to either notice, water service
to the property was shut off. Sixty-five percent of property owners responded after
receiving the initial notice.The remaining property owners corrected their defects
under threat of having their water service discontinued.
In selected areas where service lateral rehabilitation has been completed, the I/I
was reduced by an average of 42 percent. It is estimated that the annual I/I volume
in the MWWSSB service area has been reduced by 36 million gallons. The cost
of establishing the I/I program was approximately $150,000. MWWSSB spends
$207,000 annually to operate the program.
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Chapters—Technologies Used To Reduce the Impacts of CSOsand SSOs
• Reconstructing manholes in
cases of substantial structural
degradation; and
• Placing inserts and liners in
deteriorated manholes.
Inspection of the manhole components
is a necessary first step in selecting an
appropriate rehabilitation technique.
Spot repairs of manhole components
are most appropriate for addressing
minor defects, and chemical grouts
are commonly used for rehabilitating
structurally sound manholes made of
brick. Coating systems are applicable
for manholes with brick structures
that show little or no evidence of
movement or subsidence and at sites
not conducive to excavation or major
reconstruction. Structural linings
are applicable for standard manhole
dimensions (48- to 72-inch inner
diameter) where substantial structural
degradation has occurred. Structural
linings tend to be more expensive than
other rehabilitation techniques.
8.1.3 Storage Facilities
Many sewer systems experience
increased flow during wet weather. In
systems that are unable to transport or
provide full treatment for wet weather
flows, storage facilities are often used
to reduce the volume, frequency, and
duration of CSO and SSO events.
Storage facilities fill during wet
weather and are drained or pumped to
the wastewater treatment plant once
conveyance and treatment capacity
have been restored following the wet
weather event. Specific types of storage
facilities considered for this report are
summarized in Table 8.3.
Storage facilities have seen wide
application as a CSO control because
of the large and frequent volumes of
combined sewage requiring control;
however, a number of communities
have also found storage facilities,
especially flow equalization basins,
to be an effective wet weather SSO
control.
In-line Storage
In-line or in-system storage is the
term used to describe storage of wet
weather flows within the sewer system.
Taking advantage of storage within the
sewer system has broad application
and can often reduce the frequency
and volume of CSOs and SSOs
without large capital investments.
Maximization of storage in the
sewer system is also one of the NMC
required of all CSO communities. The
amount of storage potentially available
in the sewer system largely depends
on the size or capacity of the pipes
that will be used for storage and on
the suitability of sites for installing
regulating devices.
Technology Type of Pollutants/Problems Addressed
System
In-line storage CSS, SSS Peak wet weather flow rate, BOD5,TSS, nutrients, toxics,
pathogens, floatables
Off-line storage CSS, SSS Peak wet weather flow rate, BOD5,TSS, nutrients, toxics,
pathogens, floatables
On-site storage and flow CSS,SSS Peak wet weather flow rate, BOD5,TSS, nutrients, toxics,
equalization basins pathogens,floatables
Damaged manholes, such as the broken
cover shown above,can be a significant
source of storm water I/I into an SSS.
Photo: Limno-Tech, Inc.
Table 8.3
Summary of Storage
Facilities
Storage facilities have seen wide
application in attenuating peak
wet weather flows in both CSS and
SSS.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
In-line storage techniques include the
use of flow regulators, in-line tanks
or basins, and parallel relief sewers.
Flow regulators optimize in-line
storage by damming or limiting flow
in specific areas of the sewer system.
Storage tanks and basins constructed
in-line are typically governed by flow
regulators. Dry weather flows pass
directly through in-line storage tanks
or basins, and flow regulators limit
flow exiting the facility during wet
weather periods. In-line capacity can
also be created by installing relief
sewers parallel to existing sewers or
by replacing older sewers with larger
diameter pipes. Again, flow regulators
are used to optimize storage within
these facilities.
Areas where the sewer slope is
relatively flat typically offer the best
opportunities for in-line storage. One
factor that limits the applicability of
in-line storage is the possibility that
this approach can increase basement
backups and street flooding (EPA
1999g). Use of in-line storage may
also slow flow, allowing sediment and
other debris to settle in the sewer. If
allowed to accumulate, sediment and
debris can reduce available storage
and conveyance capacity. Therefore, an
important design consideration for in-
line storage is to ensure that minimum
flow velocities are provided to flush
and transport solids to the wastewater
treatment plant.
Off-line Storage
Off-line storage is the term used
to describe facilities that store wet
weather flows in near-surface storage
facilities, such as tanks and basins or
deep tunnels located adjacent to the
sewer system. Off-line storage facilities
have broad applicability and can be
adapted to many different site-specific
conditions by changing the basin size
(volume), layout, proximity to the
ground surface, inlet or outlet type,
and disinfection mechanism. For
these reasons, off-line storage facilities
are one of the most commonly
implemented CSO controls (EPA
2001a). The use of off-line storage
tends to be more expensive than in-
line storage; it is usually considered
in areas where in-line storage is
insufficient or unavailable.
A typical near-surface storage facility
is a closed concrete structure built
at or near grade alongside a major
interceptor. Deep tunnel storage
facilities are used where large
storage volumes are required and
opportunities for near-surface storage
are unavailable. As their name implies,
deep tunnels are typically located
100 to 400 feet below ground. Tunnel
diameters range from 10 to 50 feet, and
many are several miles in length.
During dry weather, untreated
wastewater is routed around, not
through, off-line storage facilities. In
contrast, during wet weather, flows
are diverted from the sewer system
to the off-line storage facilities by
gravity drainage or with pumps. The
wastewater is detained in the storage
facility and returned to the sewer
system once downstream conveyance
and treatment capacity become
available. Overflows can occur if the
capacity of off-line storage structures is
exceeded. Some treatment is provided
through settling; however, the primary
function of such facilities is storage
and the attenuation of peak wet
weather flows.
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Chapters—Technologies Used To Reduce the Impacts of CSOsand SSOs
As part of Philadelphia's effort to control CSOs, the City Water Department plans
to install three inflatable dams in large diameter sewers that have available in-line
storage. The dams will range from 11 to 15 feet high and will be automatically
controlled for both dry and wet weather conditions.The three dams will enable 16.3
MG of flow that might otherwise discharge to local receiving waters to be stored in
existing sewers per storm event, reducing CSO volumes by 650 MG per year.
The first inflatable dam, located in the city's main relief sewer, will be operational by
the end of 2004. The associated civil work projects including sewer rehabilitation
have been completed for this project. When operational, the dam will have the
ability to store up to 4 MG of combined sewage, and it is expected to reduce the
number of CSO discharges to the Schuylkill River from 32 per year to four per year.
Another inflatable dam will be installed in Rock Run during the summer of 2005.The
total cost for the installation of the dams and sewer rehabilitation is approximately
$4.8 million, or $0.29 per gallon of storage.
In-line Storage:
Philadelphia, PA
On-site Storage
On-site storage, which is storage
developed at the wastewater treatment
facility, is often an effective control
for managing wet weather flows
in systems where sewer system
conveyance capacity exceeds that
of the treatment plant. On-site
storage can play an important role in
improving treatment plant operations
by providing operators with the
ability to manage and store excess
flows. The costs associated with the
development of on-site storage are,
on average, considerably lower than
the construction costs for typical near
surface off-line storage facilities built
outside the bounds of the treatment
plant. Much of the cost savings derive
from siting storage facilities on land
already owned by the utility. It should
be noted, however, that sewer system
conveyance capacity may limit the
amount of wet weather flow that
can be brought to an on-site storage
facility, and expanding conveyance
capacity can be extremely expensive.
The two most common forms of on-
site storage are flow equalization basins
(FEBs) and converted abandoned
treatment facilities. FEBs are used to
attenuate peak wet weather flows and
to improve wet weather treatment
plant operations (Metcalf and Eddy
2003). Abandoned treatment facilities
can function in a manner similar to
FEBs in attenuating peak wet weather
flows. Abandoned facilities that have
been successfully converted for storage
include old clarifiers, treatment or
polishing lagoons, and abandoned
pretreatment facilities at industrial
sites near the treatment plant.
8.1.4 Treatment Technologies
In many systems, wet weather flows
can exceed the existing conveyance
and treatment capacity. The
development of wet weather treatment
systems presents a viable alternative
to storing excess flows. Treatment
technologies are end-of-pipe controls,
used to provide physical, biological,
or chemical treatment to excess wet
weather flows immediately prior to
discharge from a CSS or SSS. Specific
treatment technologies can address
different pollutants, such as settleable
solids, floatables, and pathogens.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
On-site Storage:
Oakland, ME
The sewer system in Oakland, Maine, consists mainly of combined sewers.The city
has been implementing CSO controls since 1997.These efforts include separating a
portion of the CSS and targeted inflow reduction activities. As a result, Oakland has
been able to eliminate both of its CSO outfalls and transport all wet weather flows
to its wastewater treatment plant. Although the city had sufficient sewer system
capacity to transport these wet weather flows, it did not have facilities capable of
treating the peak wet weather flow. The city was able to use an FEB installed at a
nearby textile mill that is no longer operating. The FEB was built in 1990 by the
textile mill as part of their pretreatment program and had not been used since the
plant closed. Oakland is able to store 0.2 MG of excess wet weather flows in the
FEB, and release it back to the wastewater plant for treatment as capacity becomes
available.The FEB is mainly used to control excess wet weather flow during spring
snowmelts. Bringing the FEB back into operation cost approximately $27,610, or
$0.14 per gallon of storage.
For the purposes of this Report to
Congress, treatment technologies are
assumed to operate intermittently,
with dry weather flows from the
CSS or SSS handled by the existing
wastewater treatment plant. Treatment
technologies considered here include
strategies for developing wet weather
treatment capacity at remote locations
in the sewer system and for enhancing
the performance of the existing
treatment facility when flows exceed
the rated capacity of the plant. Specific
technologies and operational practices
are summarized in Table 8.4 and
include:
• Constructing supplemental
treatment facilities for treating
excess wet weather flows;
• Modifying the POTW to better
accommodate high flows;
• Disinfecting excess wet weather
flows;
• Using vortex separators to provide
partial treatment for excess wet
weather flows; and
• Constructing facilities to remove
floatables from CSO discharges.
In general, treatment technologies have
not been as widely applied as other
CSO and SSO controls, partly due
to cost and the difficulty of remote
control. Also, the requirements for
permitting treated discharges from off-
site SSO facilities during wet weather
are somewhat unclear.
Supplemental Treatment
As the name implies, supplemental
treatment technologies are intended
to supplement existing wastewater
treatment capacity during periods of
wet weather. Example applications
include installing a small scale
treatment facility in a capacity-
constrained area of the sewer system,
or adding a parallel treatment process
at the existing treatment plant to be
operated only during wet weather.
Selection of a supplemental treatment
technology is determined by the
level of treatment required and the
characteristics of the wet weather flow.
Technologies commonly considered
as potential supplemental treatment
processes for excess wet weather flows
include:
• Ballasted flocculation or
sedimentation using a fine-grained
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Chapters—Technologies Used To Reduce the Impacts of CSOsand SSOs
Technology
Type of
System
Supplemental treatment CSS,SSS
Plant modifications CSS, SSS
Disinfection CSS, SSS
Vortex separators CSS
Floatables controls CSS
Pollutants/Problems Controlled
Peak wet weather flow rate, 6005,TSS, pathogens
Peak wet weather flow rate, 6005,TSS
Pathogens
TSS,floatables
Floatables
sand, or ballast, and a coagulant to
accelerate settling of solids from
wastewater;
• Chemical flocculation using metal
salts and polymers to accelerate
settling of solids from wastewater;
• Deep bed filtration with coarse
sand to filter wastewater; and
• Microscreens.
Supplemental treatment technologies
must have quick start-up times after
extended periods of no flow (or
low flow) conditions, accommodate
sudden increases in flow at unplanned
times, and provide adequate treatment
despite significant variation in
flow rates and influent pollutant
concentrations.
Plant Modifications
Simple modifications to existing
wastewater treatment facilities can
increase their ability to handle wet
weather flows. Modifications can
involve changes to the physical
configuration of various treatment
processes and the operation of
specific plant processes during
wet weather. Most modifications
require the active involvement of the
treatment plant operator to ensure
effective implementation. Example
modifications that maximize the
treatment of wet weather flows
include:
• Ensuring the even distribution of
flow among treatment units;
Table 8.4
Summary of Treatment
Technologies
Based on life-cycle cost evaluations,
treatment technologies may be an
effective technique for handling
excess wet weather flows.
The Central Treatment Plant (CTP) for the City of Tacoma, Washington, receives
flow from an SSS serving a population of 208,000. The CTP has a peak biological
treatment capacity of 78 mgd. The sewer system, however, can deliver up to 110
mgd to the CTP.Tacoma plans to install a ballasted flocculation process at the CTP,
in parallel with the existing processes, to handle wet weather flows in excess of
the peak biological treatment capacity.The ballasted flocculation process will cost
approximately $12.4 million. All related peak wet weather flow facilities upgrades
are estimated at $50.7 million. In comparison, expanding the existing activated
sludge processes would cost an estimated $130 million; this estimate does not
include the cost for additional primary clarification capacity. When the ballasted
flocculation process is brought on-line for wet weather treatment, effluent from
the process will be separately disinfected and blended with disinfected biologically
treated effluent prior to discharge.The blended effluent is expected to meet permit
limits.The ballasted flocculation process is expected to operate a maximum of 5.5
days in a row,8 days in a month,and 21 days per year (Parametrix 2001).
Supplemental Treatment:
Tacoma, WA
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Ultraviolet light is used to disinfect wet
weather flows as part of the Columbus,
Georgia, Water Works CSO Technology
Testing Program.
Photo: Columbus Water Works
• Installing baffles to protect
clarifiers from hydraulic surges
(NYSDEC2001);
• Using metal salts and polymers to
increase suspended solids removal;
• Switching the mode of delivering
flow from the primary to the
secondary treatment units;
• Switching from "series" operation
of unit processes during dry
weather flows to "parallel"
operation during wet weather
flows; and
Performance evaluations are
conducted to determine whether
additional capacity can be obtained
from existing facilities. While plant
modifications are generally more
cost effective than new construction,
some modifications that improve wet
weather performance may result in
increased concentrations of pollutants
in treatment plant effluent during dry
weather. For example, if not properly
designed, a clarifier modified for wet
weather flows may have inadequate
settling characteristics during dry
weather (Metcalf and Eddy 2003).
Further, modifications that require
operator attention before and after
a wet weather event may interrupt
regular dry weather operations and
potentially compromise the quality of
treated wastewater during dry weather.
Disinfection
Disinfection of wastewater is necessary
for public health protection when the
public may come into contact with
wastewater discharges. Wastewater
treatment plants typically include
a disinfection process designed
specifically to inactivate bacteria,
viruses, and other pathogens in the
treated wastewater. The application
of disinfection to CSO and SSO
discharges has been limited.
Achieving adequate disinfection
of excess wet weather flows can be
difficult. High flow rates can result
in reduced exposure of wastewater
to the disinfecting agent and
possibly reduced effectiveness of
the disinfection process. Among
conventional disinfection processes,
chlorine disinfection has been used
most often to successfully disinfect wet
weather flows. Effects of this method,
however, include toxic residual
chlorine and chlorine disinfection
by-products that limit the utility of
chlorination for disinfection in some
areas. Experience with ultraviolet
(UV) light and other alternatives has
increased considerably in recent years
and may be practical for wet weather
flow receiving a minimum of primary
treatment.
Vortex Separators
Vortex separators (swirl concentrators)
are designed to concentrate and
remove suspended solids and
floatables from wastewater or
storm water. Applications of
vortex separators, for the most
part, have been limited to CSSs.
Vortex separators use centripetal
force, inertia, and gravity to divide
combined sewage into a smaller
volume of concentrated sewage, solids,
and floatables; and a large volume of
more dilute sewage and surface runoff.
Typically, the concentrated sewage and
debris are conveyed to the treatment
plant, and the dilute mix is discharged
to a receiving water. This discharge
may or may not receive disinfection.
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Chapters—Technologies Used To Reduce the Impacts of CSOsand SSOs
Vortex separators provide a modest
level of treatment for a modest
cost. They are useful in controlling
suspended solids and floatables and
in reducing pollutants associated
with solids such as metals bound to
sediments. Vortex separators have
limited ability to reduce dissolved
pollutant or bacteria concentrations
unless, in the latter case, disinfection
is applied in conjunction with vortex
separation (Brashear et al. 2002).
When used in combination with
other CSO controls, the placement of
vortex separators is very important.
Because they are designed to remove
suspended solids and floatables,
vortex separators should not be placed
downstream of other facilities that
perform the same function, such as
sedimentation basins or grit chambers.
(Moffa 1997).
Floatables Controls
Floatables controls are principally
applied in CSSs and are designed to
mitigate aesthetic impacts of CSO
discharges by minimizing the amount
of litter and other debris entrained in
the CSO. Floatables controls are widely
used to control solids and floatables
in urban storm water discharges
from separate storm sewer systems.
Improvements in water quality from
floatables controls may be secondary.
The CSO Control Policy recognized
the importance of controlling solid
and floatable material by including
it under the NMC (EPA 1994a).
Floatables controls can be grouped
into three categories:
• Source controls that work to
prevent solids and floatables from
entering the CSS.
• Collection system controls that
keep solids and floatables in the
sewer system, so they can be
collected and removed at strategic
locations or transported to the
wastewater treatment plant.
• End-of-pipe controls, such as
containment booms and skimmer
boats, capture solids and floatables
as they are discharged from
the sewer system. End-of-pipe
controls can create temporary
unsightly conditions near CSO
outfalls and may be undesirable
in areas with waterfront
development.
Ensuring the efficient and effective
operation of all types of floatables
controls requires proper maintenance.
The optimal period between
maintenance activities ranges from a
few weeks to semi-annually, depending
on the technology employed.
8.1.5 Low-Impact Development
Techniques
Low-impact development (LID)
techniques seek to control the timing
and volume of storm water discharges
from impervious surfaces (e.g.,
building roofs and parking lots) to the
sewer system as well as the volume of
wastewater generated by residential,
commercial, and industrial customers.
Controlling the timing and volume
of storm water discharges can be an
important component of a program
to control CSOs. Reducing the volume
of wastewater generated within the
service area frees capacity within
both CSSs and SSSs for transport of
additional flows during wet weather.
Specific LID techniques considered for
this report are summarized in Table
8.5.
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Table 8.5
I:
Summary of Low-Impact
Development Techniques
.ow-impact development
techniques are most useful in
attenuating peak wet weather flow
rates associated with urban and
suburban storm water runoff.
Technology
Porous pavement
Green roofs
Bioretention
Water conservation
While the concept of using LID to
control storm water runoff is familiar,
the application of LID techniques
for CSO control has been limited
(University of Maryland 2002). It is
unlikely that LID techniques alone are
sufficient to fully control CSOs, yet
they have shown promise as part of
larger programs in reducing the size of
structural controls (e.g. storage). The
use of LID as an SSS control is limited
to situations in which LID might
contribute to inflow control. LID
has great potential as a storm water
control for the separate storm sewer
system that complements an SSS.
Porous Pavement
Porous pavement is an infiltration
system in which storm water
runoff enters the ground through a
permeable layer of pavement or other
stabilized permeable surface (EPA
1999h). The use of porous pavement
reduces or eliminates impervious
surfaces, thus reducing the volume of
storm water runoff and peak discharge
volume generated by a site. Reducing
the amount of stormwater that enters
the CSS increases conveyance and
storage capacity. This in turn leads
to reductions in the volume and
frequency of CSOs.
Porous pavement is used as
an alternative to conventional
impervious pavement, under certain
Type of System Pollutants/Problems Controlled
Peak wet weather flow rate
Peak wet weather flow rate
Peak wet weather flow rate
Peak wet weather flow rate
conditions. The success of porous
pavement applications depends
on design criteria including site
conditions, construction materials,
and installation methods. Typically,
porous pavement is most suitable for
areas with sufficient soil permeability
and low traffic volume. Common
applications include parking lots,
residential driveways, street parking
lanes, recreational trails, golf cart and
pedestrian paths, shoulders of airport
runways, and emergency vehicle and
fire access lanes. This technology is not
recommended for areas that generate
highly contaminated runoff such as
commercial nurseries, auto salvage
yards, fueling stations, marinas,
outdoor loading and unloading
facilities, and vehicle washing facilities,
as contaminants could infiltrate into
groundwater (SMRC 2002).
Green Roofs
Green roofs use rooftop vegetation
and underlying soil to intercept storm
water, delay runoff peaks, and reduce
runoff discharge rates and volume.
Their use can lead to reductions in the
volume or occurrence of CSOs. Green
roofs are becoming an important
tool in areas with dense development
where the use of other space-intensive
storm water management practices,
such as detention ponds and large
infiltration systems, is impractical.
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Chapters—Technologies Used To Reduce the Impacts of CSOsand SSOs
There are two basic types of green
roofs: intensive and extensive.
Intensive green roofs, also known
as conventional roof gardens, are
landscaped environments developed
for aesthetic and recreational uses that
require high levels of management.
Extensive green roofs, or eco-roofs,
make use of a continuous, thin layer
of growing medium that sustains low-
maintenance vegetation tolerant of
local climatic conditions.
Intensive and extensive green roofs
have been successfully installed in
cities across the United States, both
as part of new building design and
retrofitted to existing buildings
(e.g., Chicago, IL; Philadelphia, PA;
Portland, OR). Green roofs can be
designed for commercial buildings,
multi-family homes, industrial
structures, and single-family homes
and garages. Factors that must be
considered before installing a green
roof include the load-bearing capacity
of the roof deck, the moisture and
root penetration resistance of the
roof membrane, roof slope and shape,
hydraulics, and wind shear.
Bioretention
Bioretention is a soil and plant-
based storm water management
practice used to filter and infiltrate
runoff from impervious areas such
as streets, parking lots, and rooftops.
Bioretention systems are essentially
plant-based filters designed to mimic
the infiltrative properties of naturally
vegetated areas, reducing runoff rates
and volumes. Their use can lead to
reductions in CSO and SSO volume
and frequency. The complexity of
bioretention systems depends on the
volume of runoff to be controlled,
available land area, desired level of
treatment, and available funding.
Bioretention systems can be used as
a stand-alone practice (off-line) or
connected to a separate storm sewer
system (on-line).
Bioretention systems can be
implemented in new development or
be retrofitted into developed areas.
Bioretention systems are easier to
incorporate in new developments,
due to fewer constraints regarding
siting and sizing. They can be
applied in heavily urbanized areas,
including commercial, residential,
and industrial developments. For
example, bioretention can be used as
a storm water management technique
in median strips, parking lots with
or without curbs, traffic islands,
sidewalks, and other impervious areas
(EPA 19991).
The effectiveness of bioretention
systems depends on infiltration
capacity and treatment capability.
Systems must be sized to match
expected runoff. Runoff volumes in
excess of the system's capacity must
be handled in such a way as to avoid
erosion and destabilization of the
site. Typical maintenance activities
for bioretention systems include
re-mulching void areas; treating,
removing, and replacing dead or
diseased vegetation; watering plants
until they are established; inspecting
and repairing soil, as needed; and
removing litter and debris.
Water Conservation
Water conservation is the efficient
use of water in a manner that extends
water supplies, conserves energy,
and reduces water and wastewater
In-system netting can provide floatables
control at strategic locations in the sewer
system.
Photo: New Jersey Department of Environmental Protection
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Bioretention systems can reduce the
amount of storm water runoff generated by
impervious surfaces, such as parking lots,
that enters a CSS during wet weather.
Photo: Prince Georges County, MD
treatment costs. Reducing water use
can decrease the total volume of
domestic sewage conveyed by a sewer
system, which can increase conveyance
and treatment capacity during periods
of wet weather and potentially
reduce the volume and frequency of
CSOs and SSOs. Numerous indoor
and outdoor practices reduce water
consumption, including (GBS 2002):
• High efficiency fixtures and
appliances such as low-flow toilets,
urinals, showerheads, and faucets,
and water-efficient washing
machines and dishwashers.
• Water recycling and reuse of
wastewater from sinks, kitchens,
tubs, washing machines, and
dishwashers for landscaping,
flushing toilets, and other non-
potable purposes.
• Waterless technologies such as
composting toilets and waterless
urinals.
• Rain harvesting, in which roof
runoff is collected, stored, and
used primarily for landscaping.
In most instances, money saved
from reduced water and sewer bills
offsets installation costs over time.
Among high efficiency fixtures and
appliances, low-flow showerheads
and faucet aerators are almost always
cost-effective to install due to their
relatively low cost and minimal
labor requirements. Low-flow toilets
also have widespread application,
particularly in commercial and
institutional settings, because the
economic offset period can be
relatively short. The cost effectiveness
of the other water conservation
technologies mentioned depends on
site-specific considerations.
8.2 How Do CSO and SSO
Controls Differ?
Although many of the
technologies considered
in this report have proven
useful in controlling overflows from
both CSSs and SSSs, EPA found that
applications of certain technologies
were more common to a particular
type of system. This section highlights
technologies with particular
application in either CSSs or SSSs.
8.2.1 Common CSO Control
Measures
Implementation of the NMC was
expected to be one of the first steps
taken by CSO communities in
response to the CSO Control Policy.
In general, the NMC are controls that
reduce CSOs and their impacts on the
environment and human health, but
do not require significant engineering
studies or major construction, and
are implemented in a relatively
short period (e.g., within a few
years). Most activities completed
as part of implementing the NMC
are considered O&M practices or
collection system controls. The most
common NMC activities include (EPA
2001a):
• Sewer cleaning
• Pollution prevention
• Inflow reduction
In developing and implementing a
CSO LTCP, municipalities are expected
to consider more significant structural
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Low-flow plumbing fixtures were installed in a 60-unit low income multi-family
housing complex in Houston,Texas.The average number of occupants per unit was
4.4. Devices installed in each unit included low-flow toilets (1.6 gallons per flush),
low-flow aerators on faucets (2.2 gallon per minute) and new water meters. Faucet
leaks were repaired, and tenants were educated on conservation techniques. The
project resulted in a reduction in average monthly water consumption for the
complex from 1.3 MG pre-installation to 367,000 gallons post-installation. Average
monthly water bills for the complex decreased from $8,644 to $1,810, resulting in
savings of approximately $6,834 each month. Due to the success of the project,
Houston retrofitted four other low income housing developments with low-flow
plumbing fixtures.
Water Conservation:
Houston, TX
controls. Specifically, municipalities
are asked to evaluate the applicability
of more comprehensive collection
system controls, storage facilities, and
treatment technologies.
Sewer separation is the CSO control
most widely implemented as part of
an LTCP (EPA 200la). Complete or
limited sewer separation has been
implemented or planned by the
majority of CSO communities for
which CSO controls were documented
in the NPDES authority files that EPA
reviewed as part of data collection to
support its 2001 Report to Congress-
Implementation and Enforcement of the
CSO Control Policy. Other common
CSO control measures identified in
LTCPs include:
• Off-line storage facilities
• Plant modifications
• Sewer rehabilitation
• Disinfection facilities
8.2.2 Common SSO Control
Measures
There is no national standard
equivalent to the LTCP for
communities with SSSs that are
working to control SSOs, so it is
difficult to determine the prevalence of
specific controls. Based on interviews
EPA conducted to support the
development of this report, it appears
that communities with recurrent dry
weather SSOs tend to rely on O&M
activities, while communities with wet
weather SSOs rely more heavily on
collection system controls (e.g., inflow
reduction, rehabilitation).
8.3 What Technology
Combinations are
Effective?
Most communities evaluate
and use a wide variety of
technologies for their CSO
and SSO programs. Some technologies
have proven to be advantageous
when applied together. This section
describes several examples of
beneficial technology pairings;
this list should not be construed
as an exhaustive list of technology
combinations.
8.3.1 Inflow Reduction or Low-
Impact Development Coupled
with Structural Controls
Inflow reduction and LID techniques
reduce the quantity of storm water
runoff that enters a sewer system.
Since these controls can reduce both
the peak flow rate and volume of
storm water delivered to a sewer
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system, the size of more capital-
intensive downstream control
measures, such as storage facilities
or treatment technologies, can be
reduced, or, in some cases, eliminated
completely.
8.3.2 Disinfection Coupled with
Solids Removal
A number of the pollutants present
in wastewater can interfere with
disinfection processes and reduce
their efficacy. High concentrations of
6005, ammonia, and iron can reduce
the effectiveness of disinfection.
These substances can consume or
otherwise prevent the disinfectant
from reaching microbial pathogens.
Solids in wastewater can also interfere
physically with the disinfection
process. Pathogens can be "shielded"
by larger solids that surround and
insulate microbial pathogens from the
disinfectant (Hoff and Akin 1986).
Physical interference can be significant
for both chlorine and UV disinfection.
In general, solids removal enhances
disinfection by removing interfering
substances and by physically
removing the pathogens themselves.
The performance of disinfection
facilities to treat CSO and SSO
discharges can be improved through
the use of technologies that provide
solids control. Technologies with
demonstrated abilities to remove
solids include off-line storage facilities,
vortex separators, and supplemental
treatment facilities.
8.3.3 Sewer Rehabilitation Coupled
with Sewer Cleaning
Sewer rehabilitation is undertaken
to restore the structural integrity
of sewers and reduce infiltration.
The presence of debris and roots
within sewer systems can limit the
effectiveness of sewer rehabilitation
efforts, particularly where Shortcrete
or trenchless technologies are
employed. Therefore, it is essential
that sewer cleaning techniques are
employed prior to any scheduled sewer
rehabilitation efforts.
8.3.4 Real-Time Control Coupled
with In-line or Off-line
Storage Facilities
Real-time control technology is
used to maximize storage within the
collection system and maximize flow
to the POTW, thereby reducing the
volume and frequency of untreated
discharges. Real-time control systems
use monitoring data, operating rules,
and customized software to operate
system components (e.g., weirs,
gates, dams, valves, and pumps) in a
dynamic manner to optimize storage
and treatment. Real-time control is
most often applicable in CSSs, as these
systems tend to have substantial in-
line storage in large diameter pipes
designed to transport excess wet
weather flows. CSSs may also have off-
line storage facilities (e.g., tunnels and
basins), which can be incorporated
into a real-time control strategy. The
dynamic operation possible under
real-time control tends to require less
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storage than would be required for
similar performance without real-time
control.
8.4 What New Technologies for
CSO and SSO Control are
Emerging?
This section describes two
different broad types of
measures that have potential
for widespread implementation in
controlling the impacts of CSOs or
SSOs. These controls are viewed as
"emerging" for the following reasons:
techniques are evolving and warrant
further study; and, in general,
applications to date have been limited
to larger municipalities, although the
technologies appear to have value for
use in smaller systems. Again, this
should not be construed to be an
exhaustive list.
8.4.1 Optimization of Sewer
System Maintenance
Sewer system maintenance is critical
to providing safe and efficient service.
Optimizing sewer system maintenance
involves allocating labor, equipment,
and materials to maximize system
performance, so that the system
can efficiently collect and transport
wastewater to the treatment plant.
Determining how much maintenance
is enough is rarely straightforward,
however. Currently, there is no
standard approach for determining
the optimal frequency of various
maintenance procedures except
through experience and professional
judgement (ASCE 1999). Several
EPA regions and states, as well as
professional organizations, have
initiated efforts to develop such an
approach. These include Region 4's
MOM Program (Section 7.3.1) and
the toolkit of effective O&M practices
recently published by WERF (WERF
2003a).
8.4.2 Information Management
Effective sewer system management
largely depends on the availability
of accurate, easily accessible data.
Manual, paper-based data systems
are used to some degree in all
sewer systems (Arbour and Kerri
1998). Many utilities have been
and continue to be operated and
managed in an effective manner
without the assistance of computer-
based systems. The use of a computer
system, however, can improve data
storage and processing. Previously,
the considerable expense of such
systems limited their applicability to
larger sewer systems. As the costs of
computers and customized software
have decreased, however, these
systems are now available to most
utilities (CSU 2002). An information
management system can be designed
to meet multiple needs, including:
• Simplifying maintenance planning
and scheduling;
• Tracking workforce productivity;
• Developing accurate unit costs for
specific maintenance activities;
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• Measuring the impact of resource
allocation to various maintenance
activities; and
• Developing and tracking sewer
system performance measures.
A number of vendors have designed
software packages specifically to
assist utility staff in sewer system
management. The software is typically
a tailored database program that
provides a means for efficient data
organization, storage, and analysis.
Most software packages include
basic tools for sorting and filtering
maintenance data; many also offer
report generation capabilities. Other
software packages contain basic tools
as well as more advanced decision
support systems. Most packages
offer the ability to link to other
external data systems such as a CIS or
computer models.
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Chapter 9
Resources Spent to Address the
Impacts of CSOs and SSOs
This chapter responds to
the congressional directive
to report on the resources
spent by municipalities to address
environmental and human health
impacts of CSOs and SSOs. The
chapter presents information on
historical investments in wastewater
infrastructure, resources spent on CSO
and SSO control to date, projected
costs to reduce CSOs and SSOs, and
financing mechanisms available to
municipalities.
Most municipalities are not required
to explicitly report costs to implement
CSO and SSO controls. Therefore,
financial information on resources
spent to address CSOs and SSOs
was drawn from alternative sources,
including: LTCPs and other facility
planning documents; municipal
interviews described in Appendix
C; information on state and
local expenditures on wastewater
infrastructure from the U.S. Census
Bureau (2002, 2003a); specific
reporting categories associated with
the CWNS (EPA 2003b) and the
CWSRF (EPA 2003J); other loan and
grant programs; and federal, state, and
industry reports, such as the AMSAs
triennial financial survey (AMSA
2003a).
All cost figures in this chapter are
presented in 2002 dollars, unless
otherwise noted. Unadjusted costs are
included in Appendix M.
9.1 What Federal Framework
Exists for Evaluating
Resources Spent on CSO
and SSO Control?
At the national level, two EPA
programs provide information
on the monies spent on CSO
and SSO control, as well as anticipated
needs:
• Clean Water State Revolving Fund
(CWSRF)
• Clean Watersheds Needs Survey
(CWNS)
The CWSRF is a national program
established in 1987 under the Clean
Water Act to fund water quality
projects. Through the CWSRF, all
50 states and Puerto Rico maintain
In this chapter:
9.1 What Federal Framework
Exists for Evaluating
Resources Spent on CSO
and SSO Control?
9.2 What are the Past
Investments in Wastewater
Infrastructure?
9.3 What Has Been Spent to
Control CSOs?
9.4 What Has Been Spent to
Control SSOs?
9.5 What Does it Cost to
Maintain Sewer Systems?
9.6 What are the Projected
Costs to Reduce CSOs?
9.7 What are the Projected
Costs to Reduce SSOs?
9.8 What Funding Mechanisms
are Available for CSO and
SSO Control?
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Report to Congress on the Impacts and Control ofCSOs and SSOs
revolving loan funds to provide
low-cost financing for these projects
through low-interest loans. The
CWSRF is primarily used to fund
wastewater treatment projects, but it
can also be used for nonpoint source
pollution control and watershed and
estuary management (EPA 2003J).
The CWSRF tracks state and local
expenditures on these projects on
an annual basis, and it includes a
separate reporting category for CSO
expenditures.
The CWNS, a joint effort between
states and EPA, includes a survey of
needs of facilities for control of CSOs
along with other wastewater and
watershed needs (EPA 2003b). Survey
data are maintained in a database and
used to produce a CWNS Report to
Congress, which provides a national
estimate of needs. The CWNS and the
CWSRF do not specifically track costs
related to SSO control.
The CSO Control Policy provides
a regulatory framework for CSO
control. Under the CSO Control
Policy, communities are required
to develop and implement LTCPs.
In developing an LTCP, the CSO
Control Policy recommends that
the community complete a detailed
evaluation of CSO control alternatives
and develop a financing plan to
fund implementation of the selected
controls. This means that communities
that have completed LTCPs usually
report the anticipated cost of CSO
control in their plan.
The costs of addressing SSO problems
can vary significantly among
communities. Currently, there is no
national framework for SSO control
that requires communities to develop
and report projected or realized costs.
Therefore, more financial information
is available for CSOs than SSOs. For
the purposes of this report, the costs
to address SSOs were estimated using
information from the CWSRF, the
CWNS, and recent EPA efforts.
9.2 What are the Past
Investments in Wastewater
Infrastructure?
Municipalities, states, and
the federal government
have been investing in the
nation's wastewater infrastructure
since the late 19th century (EPA
2000a, 2000c). With passage of the
Clean Water Act in 1972, investment
in wastewater infrastructure increased
markedly. The Clean Water Act
dramatically increased funding for
the Construction Grants Program,
establishing a national policy to
provide federal grants for the
construction and upgrade of POTWs.
The Construction Grants Program
provided grants for as much as 75
percent of the total capital cost for
construction of wastewater treatment
facilities from 1970 to 1995. During
this period, the Construction Grants
Program provided a total of more
than $100 billion in federal funding
for new construction and POTW
upgrades (EPA2000a). In 1981,
amendments to the Clean Water Act
cut the authorization for POTW
grants in half and reduced the
maximum federal match to 55 percent.
Legislation was amended to phase out
the Construction Grants Program by
1991 and replace it with the CWSRF.
Federal funding for the CWSRF
totaled more than $21 billion from
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Chapter 9—Resources Spent to Address the Impacts of CSOs and SSOs
1988 to 2002, and states have made
over $47 billion available through the
CWSRF for investment in wastewater
infrastructure; both figures are in
unadjusted dollars.
As shown in Figure 9.1, federal grant
funding for capital wastewater projects
peaked in 1977 at $14.1 billion
dollars. The U.S. Census Bureau
(2002,2003a) reported that total local
and state spending on wastewater
infrastructure exceeded $535 billion
between 1970 and 2000. EPA estimates
that the current capital investment
in wastewater infrastructure from all
public sources—federal, state, and
local—is just over $13 billion annually
(EPA 2002a). Today, according
to industry organizations, local
governments and utilities pay as much
as 90 percent of capital expenditures
on wastewater infrastructure (AMSA
andWEF 1999).
Billions of Dollars
0.0
3.0
6.0
9.0
12.0
15.0
• Federal
• State and local
re
0)
Figure 9.1
Annual Capital
Expenditures
on Wastewater
Infrastructure, 1970-
2000
Federal funding for capital
wastewater projects peaked in
1977. At that time, federal funding
accounted for more than 60 percent
of annual capital expenditures
on wastewater projects; by 2000,
federal funding represented
about 15 percent of annual capital
expenditures. Details on annual
federal, state,and local expenditures
are shown in Appendix M (Tables
M.2,M.3).
Sources: Construction Grants Program and CWSRF expenditures (EPA 2000a, 2000c, 2003J); and
U. S. Census Bureau (2002).
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Figure 9.2
State and Local
Expenditures on
Wastewater O&M, 1970-
2000 (EPA 2000c, U.S.
Census Bureau 2002,
2003b)
As the value of the nation's wastewater
infrastructure increased, O&M (non-
capital) expenditures at wastewater
facilities have increased from $1.3
billion in 1970 to $18.0 billion in
2000 (Figure 9.2). O&M expenditures
now account for 60 percent of total
spending on wastewater services
(U.S. Census Bureau 2003a). AMSA
(2003b) cites a "combination of aging
infrastructure, expectations of higher
quality service, a growing population,
The majority of O&M expenditures
are borne by local governments.The
Census Bureau does not, however,
report state and local expenditures
separately.
!
and increasingly expensive federal
regulations" as contributing to
increased O&M costs.
Since 1970, total public investment in
wastewater infrastructure (capital) and
O&M exceeded $658.4 billion (EPA
2001f). According to ASCE, water and
wastewater systems are the second
largest public works infrastructure
in the country (ASCE 2003). This
infrastructure includes:
$0
$2
$4
Billions of Dollars
$8 $10 $12 $14 $16 $18
5 1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
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Chapter 9—Resources Spent to Address the Impacts of CSOs and SSOs
• 16,202 wastewater treatment
facilities;
• 21,264 sewer systems (both CSS
and SSS);
• 100,000 major pumping stations;
• 584,000 miles of sanitary sewers;
• 200,000 miles of storm sewers;
and
• 140,000 miles of combined sewers
(EPA2001gand2003b).
9.3 What Has Been Spent to
Control CSOs?
Federal funding for CSO control
projects began in 1965.
Although some communities
financed CSO controls through
the Construction Grants Program,
investment in wastewater
infrastructure during the 1970s and
1980s was focused on POTW upgrades
to secondary and advanced treatment
and expansion (EPA 200la). Federal
funding for CSO projects through the
Construction Grants Program totaled
$3.4 billion.
Since 1988, the CWSRF has been used
to provide loans to CSO communities.
CSO projects financed under the
CWSRF total $3 billion (EPA 2003J).
As shown in Figure 9.3, total state and
local expenditures reported under the
CWSRF program for CSO projects
have increased to $0.44 billion per
year in 2002. The exact percentage of
total annual municipal investment
in CSO control projects funded
through the CWSRF is not known.
Some communities participate in
the CWSRF for only a portion of
their CSO financing; others do not
participate in the program at all.
Statewide information on past
expenditures for CSO control
is available in some states. Two
coordinated surveys were conducted
in Michigan in 1999 to obtain
community and state information
on CSOs, SSOs, and other water
pollution control efforts (SEMCOG
Billions of Dollars (2002)
$0.26
$0.20
$°-41 $0.41
$0.44
$0.28
$0.19
$0.20
$0.00 $0.01
$0.13
$0.17 $0.16
$0.14
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
Year
Figure 9.3
CWSRF Annual
Expenditures for CSO
Projects, 1988-2002
(EPA 2003b)
This figure shows state and local
expenditures reported under CWSRF
Category V (CSO correction). Some
communities participate in CWSRF
for a portion of their CSO financing;
other CSO communities do not
participate at all.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
HUD and CWSRF Funding
Used to Fund Sewer
Separation:
Agawam, MA
The Town of Agawam, Massachusetts had 132 miles of combined sewer and found
sewer separation to be a cost-effective CSO control. The town spent a total of
$5.85 million to implement CSO-control measures. Funding was provided through
a Housing and Urban Development (HUD) grant in the 1970s for limited sewer
separation. CWSRF loans provided $2 million for a pump station upgrade (1996-
1997) and $3.5 million to complete the sewer separation (1999).
2001; PSC & ECT 2002). Capital CSO
control expenditures by 63 Michigan
communities exceeded $1 billion
between 1989 and 1999 (PSC & ECT
2002). It should be noted that few of
Michigan's CSO communities began
implementing controls prior to 1989.
No comprehensive source of
individual municipal expenditures
for CSO control exists. Through this
report effort, however, EPA compiled
expenditures to date for 48 CSO
communities (Appendix M). These
expenditures total $6 billion, ranging
from $134,000 to $2.2 billion per
community. Information on the unit
costs of specific control technologies
used by communities to reduce
CSOs is available in the technology
decriptions provided in Appendix L.
9.4 What Has Been Spent to
Control SSOs?
Many of the expenditures
associated with controlling
SSOs are costs associated
with renewing aging sewer system
infrastructure. This makes separating
costs specifically associated with SSO
control from standard sewer system
O&M costs difficult.
The CWSRF does not explicitly track
expenditures related to SSO control.
The CWSRF, however, does track
"I/I correction" and "sewer system
replacement and rehabilitation"
expenditures. For the purposes of this
report, these CWSRF categories of
expenditures are used as a surrogate
for SSO capital projects, with
the understanding that they may
Figure 9.4
CWSRF Annual
Expenditures for I/I and
Sewer Replacement/
Rehabilitation (EPA 2003J)
Although the CWSRF does not
specifically track expenditures
related to SSO control, spending
related to I/I correction and
sewer system replacement and
rehabilitation may serve as a
surrogate for SSO capital projects.
These categories, however, may
overestimate CWSRF expenditures
on SSO control.
Billions of Dollars (2002)
D I/I correction
• Sewer system replacement and
rehabilitation
$0.42
$0.62
$0.53
$0.04 $0.06
$0.10
$0.13
$0.001 y u
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 20002001 2002
Year
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Chapter 9—Resources Spent to Address the Impacts of CSOs and SSOs
overestimate CWSRF expenditures
on SSO control. As shown in Figure
9.4, total state and local spending
through the CWSRF on I/I correction
(Category III-A) and sewer system
replacement and rehabilitation
(Category III-B) was $0.53 billion in
2002. From 1988 to 2002, expenditures
totaled $4.0 billion. Spending in these
areas has increased over the last several
years and now exceeds expenditures
for CSO projects under the CWSRF
program (EPA 2003J). It should be
noted that communities may have
reported expenditures on SSO projects
under other categories, and not
all communities participate in the
CWSRF.
Some local cost information on
expenditures to control SSOs was
obtained as part of the municipal
interviews conducted for this report
(Appendix C). These communities
had service populations ranging
from 75 to 615,000 people. Of the
45 communities with SSSs that
participated, 29 communities provided
cost information on either capital
or O&M annual expenditures on
SSO control. As shown in Table 9.1,
the total annual capital and O&M
expenditures for these 29 communities
totaled $196.8 million. The total
annual expenditures varied with
population served, from a minimum
of $20,000 in one small village
to nearly $96 million in a major
metropolitan area.
The cost of SSO control can vary
significantly, depending on the
size and condition of the SSS, the
technologies chosen to reduce
SSOs, and regulatory requirements.
Information on the unit costs of
specific control technologies used
by communities to reduce SSOs
is available in the technology
descriptions provided in Appendix L.
9.5 What Does it Cost to
Maintain Sewer Systems?
As discussed in Section 9.2, the
current capital investment by
federal, state, and local sources
in wastewater infrastructure is $13
billion dollars per year. O&M costs
exceed $18 billion per year, more than
60 percent of total spending.
As shown in Table 9.2, average annual
O&M costs per mile of sewer are
highly varible. Various studies have
estimated average O&M costs between
$3,100-$12,500 per year per mile of
Type of Cost
Capital
O&M
Total
(capital + O&M)
Number of
Communities
19
26
29
Minimum
$6,000
$12,500
$20,000
Maximum
$75M
$20.9M
$95.9M
Total
$154.5M
$42.3M
$196.8M
Table 9.1
Annual Expenditures in
Sanitary Sewer Systems
This table shows annual capital
and O&M expenditures for 29
communities with SSSs, which
service populations ranging from 75
to 615,000.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 9.2
O&M Costs for Sewers
This table shows the average annual
O&M costs per mile of sewer. Studies
have found that O&M costs can vary
widely.
Source
WERF (1997)
ASCE (2000)
WERF (2003)
AMSA (2003a)
Annual Average O&M
costs per mile
Range of O&M
costs per mile
$1,033-$51,051
$300-$57,000
sewer. A study commissioned by ASCE
and EPA on optimizing maintenance
of SSSs estimated that utilities should
spend, on average, $8,009 per mile
annually (ASCE 1999). This study
found that it is often difficult to
develop comparable unit costs for
different O&M techniques.
Communities participating in the
interviews for this report also provided
information on O&M expenditures.
On average, these communities spent
$33,000 per mile of sewer per year on
capital projects. O&M expenditures
averaged $7,886 per mile. These
findings are consistent with the
aforementioned ASCE, WERF, and
AMSA findings.
9.6 What are the Projected
Costs to Reduce CSOs?
The CWNS is the primary
source of data on anticipated
capital needs for CSO control
at the national level.
In the 2000 CWNS, EPA estimated
future capital financial needs for
CSO control at $50.6 billion (2000
Sewer System Operation
and Maintenance Costs:
Santa Margarita Water
District, CA
Sewer System Operation
and Maintenance Costs:
Somersworth, NH
The Santa Margarita Water District
in California serves 134,000 people,
and owns and operates three
wastewater treatment plants and
539 miles of SSSs; the District
also maintains unknown miles of
private laterals. The current O&M
budget for sewer system work is
approximately $5 million a year,
with more than one-third covering
labor costs.
Lift station
maintenance
Pipe
replacement
7%
The City of Somersworth, New Hampshire, maintains 24.4 miles of sewers. Prior to
obtaining CWSRF for SSO projects, the city typically cleaned less than one mile of
sewer each year. CWSRF funding was used to purchase a $325,000 flushing truck.
In 2002, the city was able to clean 15 miles of older sewer lines for $140,000. The
city currently anticipates spending at least $15,000 per year on O&M.The city also
anticipates spending $100,000 to analyze the SSS and the separate storm sewer
system and to enter that information into a CIS.These efforts have helped reduce
the frequency of SSOs, which cost an average of $1,200 per event for cleanup.
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Chapter 9—Resources Spent to Address the Impacts of CSOs and SSOs
dollars). This estimate is based on
LTCPs and CSO planning documents
(which indicate varying levels of
control) and a model used to estimate
missing costs. Thirty-four facilities
from 10 states documented CSO
needs using LTCPs. These needs,
totaling $3.9 billion, account for 7.7
percent of the CSO needs reported in
the CWNS. EPA also reviewed other
materials (e.g., capital improvement
program budgets) submitted by states
as part of the CWNS process which
documented municipal CSO needs. In
compiling this information EPA found
documentation of approximately
$16.7 billion in needs. The CWNS
reports that a cost curve methodology
was used to estimate the cost of CSO
control where documented needs
were not provided. The cost curve
methodology is based on communities
providing primary treatment and
disinfection, where necessary, for no
less than 85% of the CSO by volume.
Compliance with current state water
quality standards could, however,
require a higher level of control
resulting in additional needs.
Some organizations have compiled
information at the state level on
estimated capital needs for CSO
control. Recent analyses conducted
for Michigan estimated that $1.7-
$3.4 billion will be needed for CSO
communities in Michigan over the
next 12 years (PSC & ECT 2002).
Estimated costs to control CSOs
in West Virginia exceed $1 billion
(Mallory2003).
Community-specific information on
projected CSO needs is available from
several sources, including LTCPs, the
Report to Congress-Implementation
and Enforcement of the Combined
Sewer Overflow Control Policy (EPA
200la) and the 2000 CWNS (EPA
2003c). Together, these sources
provide information on the future
capital needs for CSO control in 71
communities (see Appendix M).
Information on O&M costs for CSO
control is not available at the national
level.
9.7 What are the Projected
Costs to Reduce SSOs?
The 2000 CWNS identified
$3.5 billion in I/I correction
needs (Category III-A) for
facilities reported by states as having
SSO problems (EPA 2003b). A further
$10.4 billion in needs were reported
for sewer system replacement or
rehabilitation (Category III-B). The
total needs for Category III-A and
III-B were reported at $8.2 and
$16.8 billion, respectively. Needs for
Category III-A and III-B account for
only 14 percent of the total CWNS.
As shown in Figure 9.5, needs for
Category III-A and III-B have
more than doubled since the 1996
CWNS. This increase demonstrates
that communities are planning for
the correction of problems that are
symptomatic of SSOs (EPA 2003b).
In addition to the documented needs,
national modeled cost estimates for
reducing SSOs to one overflow every
five years for each SSS were prepared
for the 2000 CWNS (EPA 2003b).
EPA estimated that it would require
$88.5 billion in capital improvements
to reduce the frequency of SSOs
caused by wet weather and other
conditions, such as blockages, line
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Figure 9.5
Change in Estimated
Needs Between 1996 and
2000 CWNS (EPA 2003b)
Between the 1996 and 2000
CWNS estimated needs related to
I/I correction and sewer system
replacement and rehabilitation have
more than doubled, increasing by
122% and 118%, respectively.
nave
'
25%
I Secondary
treatment
Advanced
treatment
II-A I/I correction
III-B Sewer replace-
ment/rehab
IV-A New collector
sewers
IV-B New intercepor
sewers
V CSO correction I 2%
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Chapter 9—Resources Spent to Address the Impacts of CSOs and SSOs
SSO Abatement (EPA 2003k) and in
CSO Guidance for Funding Options
(EPA 1995a). The following sections
provide an overview of common
financing options for capital projects,
including self-financing, CWSRF loans,
and federal and state grants. Financing
options for debt repayment and O&M
costs are more limited and often rely
solely on self-financing.
9.8.1 Self-financing
Self-financing is the most common
financing option used for CSO and
SSO control. Self-financing relies on
local revenue sources including:
• Fees - user charges, property taxes,
hookup fees, development charges,
assessments, permit fees, and
special levies.
• Bonds - general obligation and
revenue bonds.
• Other local income sources -
reserves or fund transfers, interest
payments, sales, and other
mechanisms.
The AMSA Financial Survey-2003
documents that local sources (i.e.,
fees, bonds, and other sources) have
been used to fund between 90 and
95 percent of capital investment
and operating funds for wastewater
infrastructure between 1992 and 2001
(AMSA 2003a). The distribution of
revenue sources based on AMSAs most
recent financial survey is presented in
Figure 9.6.
AMSAs recent financial survey notes
that, when adjusted for inflation,
residential service rates have decreased
slightly since 1999, while rates for
industrial customers have increased
for some pollutants and decreased
for others (AMSA 2003a). Specifically
AMSA stated:
"The overall average residential
sewer service charge from 1999
to 2002 rose 7.6 percent from
$216.02 to $232.59 per year
($19.38 per month) for a single-
family residence (for common 1999
and 2002 survey respondents the
increase was only 6.0percent).
Adjusting for inflation, average
residential sewer rates have actually
decreased by 0.3 percent from 1999
to 2002 (1.9 percent for common
agencies). For industrial customers,
inflation-adjusted rates for volume
(in dollars per 1,000 gallon) and
BOD have increased by 1 and 4
percent, respectively, since 1999,
while inflation-adjusted rates for
suspended solids have decreased by
2 percent from 1999 to 2002."
Revenue Sources
T
V
V
V
T
Total
Local fees
Other sources
Bonds
CWSRF loans
Federal & state grants
Percent
66%
16%
13%
4%
1%
100%
Figure 9.6
Revenue Sources for
Municipal Wastewater
Treatment (AMSA 2003a)
Self-financing is the most common
option used to fund capital
investments and O&M activities
wastewater treatment systems.
ion
'"
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Report to Congress on the Impacts and Control ofCSOs and SSOs
The costs associated with the control
of CSOs and SSOs can be substantial
and are likely to be borne mainly at
the local level. Planning is needed to
spread costs over time, as appropriate,
in developing comprehensive, long-
term programs.
9.8.2 State and Federal Funding for
CSO and SSO Control
State and federal funding can offset
some expenditures for capital projects
needed to control CSOs and SSOs. A
local match is typically required for
state and federal funding, which can
create debt repayment pressures for
some communities (EPA 2002d).
Clean Water State Revolving Fund
CWSRF programs operate much like
banks that are capitalized with state
and federal contributions. CWSRF
monies are loaned to communities for
planning, design, and construction of
environmental infrastructure. Loan
repayments are recycled back into the
program to fund additional projects.
The CWSRF is the federal
government's major funding
mechanism for financing capital
improvements in wastewater
infrastructure, including projects to
address CSOs and SSOs. The CWSRF
is used by states to provide loans at or
below market interest rates, purchase
existing local debt obligations, and
guarantee local debt obligations. Loans
are not available for O&M or other
non-capital I/I reduction activities
(e.g., downspout disconnection
programs). As shown in Figure 9.7, the
total expenditures under the CWSRF
have increased since 1986, as has the
amount being spent on CSO control
(Category V) and on I/I correction
and sewer repairs or rehabilitation
(Category III-A and III-B, a proxy for
SSO capital) projects.
Total assets of the CWSRF program
exceed $42 billion. States have
significant control over the CWSRF
funds. States set loan terms, including
maximum loan amount, fees, interest
rates (from zero percent to market
Figure 9.7
=
State and Local
Expenditures Under
the CWSRF Program for
CSO Correction and SSO
Capital Projects
Total expenditures under the CWSRF
have generally increased since
program inception in the late 1980s.
Billions of Dollars (2002)
D CSO correction
d SSO capital projects (I/I correction and
sewer rehabilitation)
• All other CWSRF expenditures
$3.9
$2.9 $2.9
$2.5
$5.1
$5.0
$4.3
$3.4
$3.5 $3.5
$2.9
$3.1
$1.3
• I
$^102
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
Year
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Chapter 9—Resources Spent to Address the Impacts of CSOs and SSOs
rate, sometimes on a sliding scale
based on community economics),
repayment periods (up to 20 years),
requirements on repayment dollars,
prioritization requirements, and
many other features of the program.
In some cases, legislative approval is
required for changes. Twenty-six states
are leveraging the federal funding by
issuing bonds. States can also tailor
their CWSRF programs to leverage
a number of financing mechanisms
to make funding opportunities more
attractive for communities. Options
include loans; refinancing, purchasing,
or guaranteeing local debt; and
purchasing bond insurance.
Federal Grants
As discussed in Section 9.3 of this
report, federal water pollution
control grants for CSO control were
available as early as 1965. The federal
Construction Grant Program was
used extensively during the 1970s
and 1980s to fund construction of
wastewater infrastructure, and several
communities used this program to
fund CSO projects. The program was
phased out in the late 1980s in favor of
the CWSRF.
Several other grant programs—the
Rural Utilities Service Grant
Program, the Economic Development
Administration Grant Program, and
Community Development Block
Grants—also are used for CSO and
SSO control projects, but they are only
available to small and economically
disadvantaged communities.
State Grants for CSO Control
Twenty-eight states have grant
programs specifically to help
communities implement CSO
projects (EPA 200la). These programs
vary significantly in funding level
and restrictions; many incorporate
CWSRF loan funding. Most of these
state programs are targeted at small
The City of Lawton, Oklahoma, is using CWSRF loans along with utility rate increases
to fund rehabilitation and replacement of the SSS. The project is separated into
three 7-year phases. The first phase ends in 2004. By establishing a Sanitary Sewer
Technical Division for design in May 1998 and a Construction Division in January
1999, the city has been able to complete many of the tasks associated with this
project on its own. While costs for Phase I were estimated to be $22 million, actual
costs held to $16.8 million (see table below). This cost difference is the result of city
efforts to use in-house designers and contractors. Actual costs for the remaining
phases of this project are expected to be substantially lower.
Contract and Actual Costs for Lawton, OK SSS Rehablitation Project
Phase Contract Actual Projected SRF
Cost Cost Acutal Loan
Cost
I
II
III
$22M
$37M
$40M
$16.8M
$28M
**
$15M
$28M*
Lawton has qualified for this loan but has not borrowed the money yet.
* It is too early for a projected cost for Phase III.
CWSRF Loans Fund SSO
Control:
Lawton, OK
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Report to Congress on the Impacts and Control ofCSOs and SSOs
State Grants for CSO
Control:
Hartford and
New Haven, CT
Connecticut's state grant program for CSOs has provided $173 million to eight
communities. Without this funding, the City of Hartford would have been unable
to proceed with CSO control, because independently the city could not issue $80
million in debt.The state grant program also allowed the City of New Haven to meet
its 12 to 15-year schedule for the LTCP, and the program kept user rates below EPA's
affordability cap (EPA 2002d).
and/or economically disadvantaged
communities, and often have fairly low
funding levels.
States with grant programs for CSO
control include Connecticut, Vermont,
and Maine. Connecticut established
a CSO grant program in 1986 that
provides grants for 50 percent of the
federal eligible project costs, and a
CWSRF loan at 2 percent interest for
the remaining costs. Vermont has a
similar program that requires a 25
percent local match, provides a 25
percent grant for construction costs,
and allocates CWSRF loans for the
remainder. Maine has a state bond
issue for $2.4 million that funds grants
awarded for 25 percent of the cost of
development of CSO Master Plans, the
functional equivalent of an LTCR
State Grants for SSO Control
Oklahoma and North Carolina are
examples of states with targeted grant
programs, primarily aimed at making
funding more readily available for
rural areas, that have been used for
SSO control projects. Oklahoma's
Water Resources Board administers
the CWSRF, provides low-interest
bonds, and provides competitive
funding through a Rural Economic
Assistance Program (REAP). REAP
provides grants between $50,000 and
$100,000 for towns with populations
between 500 and 1,000. The state has
awarded 379 REAP grants for a total
of $32.7 million. North Carolina's
General Assembly funded a program
of grants called the High Unit Cost
Program through issuance of state
bonds in 1987 and again in 1993.
State Grants for CSO
Control:
Springfield and
Rutland, VT
Vermont's grant program helped the Town of Springfield make CSO projects more
acceptable to voters. The town recently finished a $4 million project for which it
received $1 million in state grant funds and a 50-percent loan at close to zero-
percent interest. In Rutland, the Commissioner of Public Works also stated that grant
funds were beneficial and helped keep user rates down (EPA 2002d).
State Grants for SSO
Control:
Nowata, OK
Nowata, Oklahoma, secured $250,000 from the Community Development Block
Grant Program and $79,000 from the Oklahoma REAP grant program to replace
7,000 feet of failing sanitary sewer line. Prior to receiving the grants, Nowata was
able to replace 3,000 feet of sewer.The city plans to replace an additional 3,000 feet
in the next five years. The grants represented a significant source of funding to the
Maintenance Department, which operates with a $190,000 annual budget.
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Chapter 10
Conclusions and
Future Challenges
This report has been prepared
in response to a request by
Congress for information
related to CSOs and SSOs. EPA
collected data and performed
technical analyses to determine the
environmental and human health
impacts of CSOs and SSOs; the
location, volume, frequency, and
constituents of such discharges; the
technologies used by municipalities
to address CSOs and SSOs; and the
resources spent by municipalities on
CSO and SSO control.
In its preparation of this report, EPA
found that:
• The occurrence of CSOs and
SSOs is widespread. CSOs and
SSOs contain pollutants that
are harmful to the environment
and human health, and there is
evidence that CSOs and SSOs
may cause or contribute to
environmental and human health
impacts.
• CSOs and many SSOs are caused
by wet weather conditions and
occur at the same time that storm
water and other nonpoint source
pollutant loads are delivered to
surface waters. This often makes
it difficult to directly attribute
specific water quality impacts to
CSOs and SSOs. This suggests that
a holistic approach should be used
to address wet weather impacts.
• There are many existing structural
and non-structural technologies
that are well-suited for CSO and
SSO control. Implementation
of emerging technologies
and improved information
management hold promise
for increased effectiveness and
efficiency.
• Costs associated with the
technologies for controlling CSOs
and SSOs are often substantial.
Planning is needed to spread
costs over time, as appropriate, in
developing comprehensive, long-
term programs.
These findings are consistent with
programmatic initiatives currently
being implemented by EPA's Office
of Water. They correspond with
emerging needs and the findings
In this chapter:
Protecting Infrastructure
Implementing the Watershed
Approach
Improving Monitoring
and Information-Based
Environmental Management
Building Strategic
Partnerships
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Report to Congress on the Impacts and Control ofCSOs and SSOs
of other recent studies such as the
National Water Quality Inventory, the
BEACH Program, the Gap Analysis,
and the Clean Watersheds Needs
Survey. Further, they support EPA's
position that discharges from urban
areas—particularly wet weather
discharges resulting from rainfall or
snowmelt—continue to be significant
contributors to water quality
impairments nationwide.
Current challenges for clean water
encompass CSO and SSO control, and
include:
• Protection of existing
infrastructure;
• Development, approval, and
implementation of CSO LTCPs
under the CSO Control Policy;
• Development and implementation
of SSO controls;
• Implementation of Best
Management Practices (BMPs)
to reduce pollution from storm
water runoff in accordance with
EPA's Storm Water Phase I and II
Programs;
• Integration of wet weather
programs to increase the value of
monitoring, reporting, tracking,
and permitting to support
information-based environmental
management;
• Coordination of permits on a
watershed basis; and
• Maintenance of valued
partnerships with key stakeholder
groups.
Several initiatives and actions that will
enable EPA, states, municipalities, and
citizens at large to achieve success in
meeting these future challenges are
described below.
Protecting Infrastructure
Since 1972, EPA has worked to
implement the Clean Water Act
as it relates to the collection,
conveyance, and treatment of
wastewater. The national investment
in municipal wastewater infrastructure
has been substantial. This investment
has resulted in water quality and
human health improvements
throughout the United States. Today,
however, the nation's wastewater
infrastructure is aging and in need
of attention. The continued ability of
existing infrastructure to safeguard the
clean water accomplishments realized
since 1972 is at risk. Further, its ability
to serve as the platform for future
expansion of wastewater collection
and treatment capacity is jeopardized.
Proper O&M of the nation's sewers is
integral to ensuring that wastewater
is collected, transported, and treated
at POTWs; and to reducing the
volume and frequency of CSO and
SSO discharges. Municipal owners
and operators of sewer systems and
wastewater treatment facilities need
to manage their assets effectively
and implement new controls, where
necessary, as this infrastructure
continues to age. Innovative responses
from all levels of government and
consumers are needed to close the gap.
10-2
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Chapter 10—Conclusions and Future Challenges
Implementing the Watershed
Approach
CSOs and SSOs are two among
many sources of pollution that
can impact receiving water
quality. The watershed approach is
central to water quality assessments
and the identification of control
strategies that include all sources of
pollution that affect water quality.
The presence of sewer systems in
most developed watersheds across
the country underscores the potential
for SSOs to affect water quality on
a widespread basis. Similarly, the
presence of CSOs in 32 states places
them in many watersheds across the
country.
As described in this Report to
Congress, CSOs and wet weather
SSOs occur simultaneously with
the generation of storm water and
other forms of nonpoint source
pollution, making it difficult to
identify and assign specific cause-
and-effect relationships to observed
water quality problems. Attainment
and maintenance of water quality
standards requires that appropriate
attention is given to all sources.
Better integration of all of EPAs wet
weather programs will provide for
Sanitation District No. 1 of Northern Kentucky received an EPA grant to work
with the State of Kentucky to develop a watershed permitting approach and to
investigate the feasibility of implementing the approach. The District includes
Campbell, Kenton, and Boone counties, and covers an area of 580 square miles.
Located on the southern bank of the Ohio River, directly across from Cincinnati,
Ohio, this three-county area contains approximately 40 incorporated cities, each
with its own political and administrative structure.
Prior to July 1995, the operation and maintenance of the sewer systems in these
counties was the responsibility of the respective municipal jurisdictions. Ownership
for most of the sewer systems in Northern Kentucky was transferred to the District in
1995 as a result of revisions to state legislation. With this consolidation, the District
became responsible for managing 1,400 miles of combined and separate sanitary
sewers, one major wastewater treatment facility, eight small wastewater treatment
facilities, and approximately 100 CSO outfalls. Recently, with the development of a
regional facilities plan, the District has embarked on a program to construct two
new regional wastewater treatment facilities at a cost of more than $200 million
over the next 10 years. In addition, the District is responsible for implementing a
CSO LTCP that includes an integrated watershed approach to planning and an
SSO Plan (requested by the Kentucky Division of Water) to reduce the number of
unauthorized discharges.
At this time, the District and the Kentucky Division of Water have agreed to pursue
additional dialog on the development of a draft watershed permit for Banklick
Creek. This watershed was selected because it is impacted by urban storm water
runoff, CSOs, SSOs, septic systems, and rural runoff. It should be noted that the
District's wastewater treatment plant does not discharge into the Banklick Creek
watershed. The new watershed permit will enable the District to invest resources
(time, labor, and money) more effectively in water quality improvement projects.
The watershed permitting approach will also take advantage of the extensive
database of water quality and CIS information that the District has compiled for
its service area. Further, it provides an opportunity to consolidate monitoring and
reporting activities.
Implementing the
Watershed Approach:
Kentucky
10-3
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Improving Monitoring
and Information-
Based Environmental
Management:
Wisconsin
some economies of scale in achieving
this end. Similarly, concentration
of resources under the watershed
approach will help advance the control
of CSOs and SSOs in a cost-effective
manner.
Improving Monitoring
and Information-Based
Environmental Management
In developing this Report to
Congress, EPA found that
the data necessary to answer
many of Congress' questions were
limited. Improved monitoring
and reporting programs would
provide better data for decision-
makers to assess the frequency and
magnitude of CSO and SSO events,
the impact these discharges have on
the environment and human health,
and the importance of CSO and
SSO discharges with respect to other
pollution sources.
Numerous federal, state, and local
government agencies as well as non-
governmental organizations and
citizens are involved in monitoring.
Monitoring and reporting efforts
include collection of water quality
information, tracking impacts of
known activities affecting water
quality, linking water quality to human
health, and other activities. Effective
monitoring programs provide the data
and information needed to support
sound decision making. Too often,
however, the monitoring data do not
meet the needs of specific programs
or are not readily available. Better
alignment of monitoring programs to
address environmental management
and human health issues is needed.
Improved monitoring and reporting
may foster a better understanding of
cause-and-effect relationships. It may
also improve state/local government
and citizen access to environmental
information.
Along with improved monitoring and
reporting, data need to be effectively
managed. Modernization of EPAs
PCS will help in this regard. Use
of standardized reporting formats
for information on the occurrence
A cooperative effort between the Milwaukee Metropolitan Sewerage District
(MMSD), the Wisconsin Department of Natural Resources, USGS, and several
academic institutions resulted in the development of a single database for
environmental data.The project team is compiling data sets from various federal,
state, and local agencies in a centralized database of hydrology, water chemistry,
macroinvertebrate, fish, habitat, and CIS information for stream corridors in the
MMSD service area. The database is available on-line and allows the user to run
queries and retrieve data currently in the system.
The database serves as a comprehensive inventory of stream corridor conditions,
allowing for an improved understanding of the inter-relationship between the
various types of data and establishing a baseline of existing conditions. Using these
baseline conditions, impairments can be identified and assessed,and strategies can
be developed to address the most significant problems. MMSD plans to use the
database as a tool to prioritize future efforts to control CSO, SSO, and storm water
discharges. Future data incorporated into the database will allow verification of
improvements and identification of necessary adjustments or additional steps.
10-4
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Chapter 10—Conclusions and Future Challenges
and control of CSOs and SSOs will
enable EPA, states, and others to track
pollutant loads and performance
measures. Further, recent EPA efforts
such as Watershed Assessment,
Tracking, and Environmental Results
(WATERS) are working to unite
national water quality information
that was previously available only from
several independent and unconnected
databases.
Building Strategic Partnerships
The success that the nation
has achieved in improving
water quality since passage
of the Clean Water Act is due to the
The Watershed Initiative for a Safer Environment (WISE) was started by the Cities
of Elkhart, Mishawaka, and South Bend, Indiana.These cities have 102 CSO outfalls
that discharge to 48 miles of the St. Joseph and Elkhart Rivers. Land use within the
two-county area is 72 percent rural. Concentrations of £ coli in the main stem and
at the mouths of the tributaries routinely exceed water quality standards. A single
watershed tool was needed to educate the public and to assist in the selection of
cost-effective strategies to reduce point and non-point pollutant sources, including
CSOs.WISE utilized a stakeholder-driven approach to watershed planning involving
numerous stakeholders, including:
Indiana Department of Environmental Management
City of Elkhart Public Works & Utilities
City of Goshen Wastewater Utility
City of Mishawaka Wastewater Utility
City of South Bend Wastewater Utility
Elkhart County Planning Division
Jimtown Community School Corporation
Juday Creek Task Force
Local Farm Bureau Agency
Michiana Area Council of Governments
St. Joseph County Area Plan Commission
St. Joseph County Surveyor
St. Joseph and Elkhart County Health Departments
St. Joseph and Elkhart County Soil and Water Conservation Districts
Concerned citizens
WISE secured federal funding through the Clean Water Act 205(j) grant program
to conduct coordinated river sampling and to develop a calibrated water quality
model of the two rivers. WISE also expects to receive a 104(b)(3) grant in January
2004 to continue development of the model, including:
• Isolating the sources of £ coli;
• Identifying additional types of appropriate controls;
• Displaying the anticipated improvements in river water quality from
different source controls along with the cost for implementation; and
• Evaluating whether refined water quality standards are appropriate.
This work will provide a single model that can be used in NPDES programs to
further refine contaminant sources and assist in the selection of cost-effective
strategies toward meeting, and possibly refining, water quality standards.
Strategic Partnerships:
Indiana
10-5
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Report to Congress on the Impacts and Control ofCSOs and SSOs
collective efforts of federal and state
agencies, municipalities, industry,
non-governmental organizations, and
citizens. Maintenance and enhancing
existing cooperation among these
groups is essential to meet the
challenges to clean water that lie ahead.
As described in this Report to
Congress, threats to water quality
and human health have numerous
origins and sources; establishing direct
cause-and-effect relationships is often
difficult. The information necessary to
manage water quality problems also
comes from many sources.
EPA recognizes the value of working
with stakeholders and has pursued
a strategy of extensive stakeholder
participation in its policy-making
on CSO and SSO issues. This
effort should continue to improve
knowledge on the impacts of CSOs
and SSOs. Similarly, as communities
continue to implement CSO and
SSO controls, further cooperation
with municipal, industry, and
environmental organizations
is essential to ensure successful
development and implementation of
environmental programs.
10-6
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Appendix A
Statutes, Policies,and Interpretive
Memoranda
A.1 Consolidated Appropriations Act
for Fiscal Year 2001 (P.L. 106-554)
A.2 Combined Sewer Overflow
(CSO) Control Policy
A.3 Memorandum:Addition
of Chapter X to Enforcement
Management System
A.4 Enforcement Management
System-ChapterX: Setting
Priorities for Addressing
Discharges from Separate
Sanitary Sewers
-------
-------
Appendix A
A.1 Consolidated Appropriations Act for Fiscal Year 2001 (P.L. 106-554)
December 15, 2000
CONGRESSIONAL RECORD —HOUSE
H12273
SFC. m Wer WtATHfK WATER QUALITY, (a)
COMeiNto SEWER OVERFLOWS Section 402 of
the Federal Water Pollution Control Act (33
U.$.C 1342) is amended lay adding at the end
the following:
"M COMBINED SeWfR OVFRFl_OWS,~
"(1) RfQUIKEMENT FOR PERMITS. ORDERS, AND
DECREES.—Each permit, order, or decree issued
pursuant to this Act after the date of enactment
of this subsection for a discharge from a munic-
ipal combined storm and sanitary sewer shall
conform to the Combined Sewer Overflow Con-
trol Policy signed by the Administrator on April
11, 1994 (in this subsection referred to as the
'CSO control policy').
"(2) WATER QUALITY AND otsicnATED USE RE-
VIEW GUIDANCE.—Not later than July 31. 2O01,
and after providing notice and opportunity for
public comment, the Administrator shall issue
guidance to facilitate the conduct of water qual-
ity and designated use reviews for municipal
combined sewer overflew receiving waters.
"(3) REPORT.—Not later than September 1,
2001, the Administrator shall transmit to Con-
gress a report on the progress made by the Envi-
ronmental Protection Agency, States, and mu-
nicipalities in implementing and enforcing the
CSO control policy.".
(b) WET WEATHER PILOT PKIKHAM.—Title I of
the Federal Water Pollution Control Act (33
U.S.C. 1?S1 et seq.) Is amended by adding at the
end the following:
"SEC. 111. WET W&ATHRR WATERSHED PILOT
PROJECTS.
"(a) IN GENERAL.—The Administrator, in co-
ordination with the Stales, may provide tech-
nical assistance and grants for treatment works
to carry out pilot projects relating to the fol-
lowing areas of wet weather discharge control:
"(1) WATERSHED MANAGEMENT a^ WLI WEATH-
LN DISCHARGES.—The management of municipal
combined sewer overflows, sanitary sewer over-
flows, and stormwater discharges, on an inte-
grated watershed or iubwatershed basis for the
purpose of demonstrating the effectiveness of a
unified wet weather approach.
"(2) STORMWATF.R REST MANAGiMtNT PRAC-
TICES.—The control of pollutants from munic-
ipal separate storm sewer systems for the pur-
pox of demonstrating and determining controls
that are cost-effective and that use innovative
technologies in reducing such pollutants from
stormwater discharges.
"(b) ADMINISTRATION.—The Administrator, in
coordination with the States, shall provide mu-
nicipalities participating in a pilot project under
this section the ability to engage in innovative
practices, including the ability to unify separate
wet weather control efforts under a single per-
mit.
"(c) FUNDING.—
"ft) IN GENERAL.—There is authorized to ba
appropriated to carry out this section f 10,000.000
for fiscal year 2002, t15.000.QOO for fiscal year
2003, and 00,000,000 for fiscal year 2004. Such
funds shall remain available until expended.
"(!) STORMWATER.—The Administrator shall
make available not less than 20 percent of
amounts appropriated for a fiscal year pursuant
to this subsection to carry out the purposes of
subsection (a)(2).
"(3) ADMINISTRATIVE EXPENSES.—The Admin-
istrator may retain not to exceed 4 percent of
any amounts appropriated for a fiscal year pur-
suant fo this subsection for the reasonable and
necessary costs of administering this section.
"(d) REPORT TO CONGRESS.—Not later than 5
years after the date of enactment of this section,
the Administrator shall transmit to Congress a
report on the results of the pilot projects con-
ducted under this section and their possible ap-
plication nationwide.".
(c) SEWER OVERFLOW CONTKOL GRANTS.—Title
II of the Federal Water Pollution Control Act
(33 U.$.C. 1341 et seq.) is amended by adding at
the end the following:
-S«C. 1S1. SBWSH OVERFLOW CONTROL GRANTS.
"(a) IN GENERAL.—In any fiscal year in which
the Administrator has available for obligation at
least S13SO.OOO.OOO for the purposes of section
sot—
"(1) the Administrator may make grants to
States for the purpose of providing grants to a
municipality or municipal entity for planning.
design, and construction of treatment works to
intercept, transport, control, or treat municipal
combined sewer overflows and sanitary sewer
overflows: and
"(i) subject to subsection (g), the Adminis-
trator may make a direct grant to a munici-
pality or municipal entity for the purposes de-
scribed in paragraph (1).
"(b) pRiORiTiZATiON.—ln selecting from
among municipalities applying for grants under
subsection (a), a State or the Administrator
shall give priority to an applicant that—
"(1) is a municipality that is a financially dis-
tressed community under subsection (c):
1 '(2) has implemented or is complying with an
implementation schedule for the 9 minimum con-
trols specified in the CSO control policy referred
to In section 402(q)(1) and has begun imple-
menting a long-term municipal comoined sewer
overflow control plan or a separate sanitary
sewer overflow control plan,- or
"(3) is requesting a grant for a project that is
on a State's intended use plan pursuant to sec-
tion 606fc): or
' '(4) is an Alaska Native Village.
"(c) FINANCIALLY DISTRESSED COMMUNITY.—
"(I) DEFINITION.—In subsection (b), the term
'financially distressed community' means a com-
munity that meets sffordability criteria estab-
lished by the State In which the community is
located, if such criteria are developed after pub-
lic review and comment.
' '(2) CONSIDER* TION OF IMPACT ON WA TER AND
SfWtR KAILS.—In determining if a community is
a distressed community for the purposes of sub-
section (b), the State shall consider, among
other factors, the extent to which the rate of
growth of a community's tax basf has been his-
torically stow such ttiat implementing a plan de-
scribed in subsection (of (2} would result in a sig-
nificant increase in any water car sewer rote
charged by the community's publicly owned
wastewater treatment facility.
"(3) INFORMATION TO ASSIST STATES.—The Ad-
ministrator may publish infonnalion to assist
States in establishing afforttabtlity criteria
under paragraph (1).
"(d) COST SHARING.—The Federal share of the
cost of activities carried out using amounts from
a grant made under subsection (a) shall be not
less than SS percent of the cost. The non-Fed-
eral share of the cost may include, in any
amount, public and private funds and In kind
services, and may include, notwithstanding sec-
tion 603(h), financial assistance, including
loans, from a State water pollution control re-
volving fund.
"(e) AOMINISTKATIVE REPORTING REQUIRE-
MENTS—If a project receives grant assistance
under subsection (a) and loan assistance from a
State water pollution control revolving fund and
the loan assistance is for 1$ percent or more of
the cost of the project, the project may be ad-
ministered in accordance with State water pol-
lution control revolving fund administrative re-
porting requirements for the purposes of stream-
lining such requirements.
"(f) AUTHORIZATION OF APPROPRIATIONS.—
There is authorized to oe appropriated to carry
out this section S750,000,ooo for each of fiscal
years 200! and 2003. Such sums shall remain
available until expanded.
' '(g) ALLOCATION OF FUNDS.—
"(i) FISCAL VF.M aw—Subject to subsection
(h). the Administrator shall use the amounts ap-
propriated to carry out this section for fiscal
year 2002 for making grants to municipalities.
and municipal entities under subsection (a)(2),
in accordance with the criteria set forth in sub-
section (b).
"(2) FISCAL y«ff 2003.—Subject to subsection
(h), the Administrator shall use the amounts ap-
propriated to early out this section for fiscal
year 2003 as follows:
"(A) Not to exceed (250,000,000 for making
grants to municipalities and municipal entitles
under subsaction (a)(2), in accordance with the
criteria set forth in subsection (b).
1YSJ All remaining amounts for making grants
to States under subsection (a)(1), in accordance
with a formula to oe established by the Adminis-
trator, after providing notice and an oppor-
tunity for public comment, that allocates to
each State a proportional share of such amounts
based on the total needs of the State for munic-
ipal combined sewer overflow controls and sani-
tary sewer overflow controls identified in the
most recent survey conducted pursuant to sec-
tion SiefblO).
"(h) ADMINISTRATIVE EXPENSES.—or the
amounts appropriated to carry out this section
for each fiscal year—
"(1) the Administrator may retain an amount
not to exceed 1 percent for the reasonable and
necessary costs of administering this section;
and
"(!) the Administrator, or a State, may retain
an amount not to exceed 4 percent of any grant
made to a municipality or municipal entity
under subsection (a), for the reasonable and
necessary costs of administering the grant.
"(i) REPORTS,—Not later than December 31.
2003, ana periodically thereafter, thm Adminis-
trator shall transmit to Congress a report con-
taining recommended funding levels for grants
under this section. The recommended funding
levels shall be sufficient to ensure the continued
expeditious Implementation of municipal com-
bined sewer overflow and sanitary sewer over-
flow controls nationwide.",
(d) INFORMATION ON CSOS AND 5SO5.—
(i) REPORT TO CONGRESS.— Nat later then 3
years after the date of enactment of this Act,
the Administrator of the Environmental Protec-
tion Agency shall transmit to Congress a report
summariifng—
A-1
-------
Report to Congress on the Impacts and Control ofCSOs and SSOs
H12274 CONGRESSIONAL RECORD CHOUSE December 15,2000
(A) the extent of the human health and envi-
ronmental impacts caused by municipal com-
bined wivsr overflow* and sanitary sewer over-
flows, including the location of discharges caus-
ing such impacts, the volume of pollutants dis-
charged, and the constituents discharged;
(B) the resources spent by municipalities to
address these impacts; and
(C) an avafuation of the technologies used by
municipalities to address these impacts.
(2) TeCHNQL QGY CL EARiNGHOUSt:.—After
transmitting a report under paragraph (J), the
Administrator shall maintain a clearinghouse of
cost-effective and efficient technologies for ad-
dressing human health find environmental im-
pacts due to municipal combined sewer over-
flows and sanitary sewer overflows.
A-2
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A.2 Combined Sewer Overflow (CSO) Control Policy
Appendix A
18688 Federal Register / Vol. 59, No. 75 / Tuesday. April 19, 1994 / Notices
ENVIRONMENTAL PROTECTION
AGENCY
[FRL-473Z-7]
Combined Sewer Overflow (CSO)
Control Policy
AGENCY: Environmental Protection
Agency (EPA).
ACTKm: Final policy.
SUMMARY: EPA has issued a national
policy statement entitled "Combined
Sewer Overflow (CSO) Control Policy."
This policy establishes a consistent
national approach for controlling
discharge* from CSOs to the Nation's
waters through the National Pollutant
Discharge Elimination System (NPDES)
permit program.
Few FURTHER INFORMATION CONTACT:
Jeffrey Lape. Office of Wastewater
Enforcement and Compliance, MC—
4201, U.S. Environmental Protection
Agency. 401 M Street SW., Washington,
DC 20460. (202) 260-7361.
SUPPLEMENTARY INFORMATION: The main
purposes of the CSO Control Policy are
to elaborate on the Environmental
Protection Agency's (EPA's) National
CSO Control Strategy published on
September 8.1989. at 54 PR 37370. and
to expedite compliance with the
requirements of the Clean Water Ad
(CWA). While implementation of the
1389 Strategy has resulted in progress
toward controlling CSOs, significant
public health and water quality risks
remain.
This Policy provides guidance to
permittees with CSOs, NPDES
authorities and State water quality
standards authorities on coordinating
the planning, selection, and
implementation of CSO controls that
meet the requirements of the CWA and
allow for public involvement during the
decision-mating process.
Contained in the Policy are provisions
for developing appropriate, site-specific
NPDES permit requirements for all
combined sewer systems (CSS) that
overflow as a result of wet weather
events. For example, the Policy lays out
two alternative approaches—the
"demonstration" and the
"presumption" approaches—that
provide communities with targets for
CSO controls that achieve compliance
with the Act, particularly protection of
water quality and designated uses. The
Policy also includes enforcement
initiatives to require the immediate
elimination of overflows that occur
during dry weather and to ensure that
the remaining CWA requirements are
complied with as soon as practicable.
The permitting provisions of the
Policy were developed as a result of
extensive input received from key
stakeholders during a negotiated policy
dialogue. The CSO stakeholders
included representatives from States.
environmental groups, municipal
organizations and others. The negotiated
dialogue was conducted during the
Summer of 1992 by the Office of Water
and the Office of Water's Management
Advisory Group. The enforcement
initiatives, Including one which is
underway to address CSOs during dry
weather, were developed by EPA's
Office of Water and Office of
Enforcement.
EPA Issued a Notice of Availability on
the draft CSO Control Policy on January
19,1993. (58 FR 4994) and requested
comments on the draft Policy by March
22,1993. Approximately forty-one sets
of written comments were submitted by
a variety of interest groups including
cities and municipal groups.
environmental groups, States,
professional organizations and others.
All comments were considered as EPA
prepared the Final Policy. The public
comments were largely supportive of
the draft Policy. EPA received broad
endorsement of and support for the key
principles and provisions from most
commentary. Thus, this final Policy
does not include significant changes to
the major provisions of the draft Policy,
but rather, it includes clarification and
better explanation of the elements of the
Policy to address several of the
questions that were raised in the
comments. Persons wishing to obtain
copies of the public comments or EPA's
summary analysis of the comments may
write or call the EPA contact person.
The CSO Policy represents a
comprehensive national strategy to
ensure that municipalities, permitting
authorities, water quality standards
authorities and the public engage in a
comprehensive and coordinated
planning effort to achieve cost effective
CSO controls that ultimately meet
appropriate health and environmental
objectives. The Policy recognizes the
site-specific nature of CSOs and their
impacts and provides the necessary
flexibility to tailor controls to local
situations. Major elements of the Policy
ensure that CSO controls are cost
effective and meet the objectives and
requirements of the CWA.
The major provisions of the Policy are
as follows.
CSO permittees should immediately
undertake a process to accurately
characterize their CSS and CSO
discharges, demonstrate implementation
of minimum technology-based controls
identified in the Policy, and develop
long-term CSO control plans which
evaluate alternatives for attaining
compliance with the CWA, including
compliance with water quality
standards and protection of designated
uses. Once the long-term CSO control
plans are completed, permittees will be
responsible to implement the plans'
recommendations as soon as
practicable.
State water quality standards
authorities will be involved in the long-
term CSO control planning effort as
well. The water quality standards
authorities will help ensure that
development of the CSO permittees'
long-term CSO control plans are
coordinated with the review and
possible revision of water quality
standards on CSO-impacted waters.
NPDES authorities will issue/reissue
or modify permits, as appropriate, to
require compliance with the technology-
based and water quality-based
requirements of the CWA. After
completion of the long-term CSO
control plan, NPDES permits will be
reissued or modified to incorporate the
additional requirements specified in the
Policy, such BS performance standards
for the selected controls based on
average design conditions, a post-
construction water quality assessment
program, monitoring for compliance
with water quality standards, and a
reopener clause authorizing the NPDES
authority to reopen and modify the
permit if it is determined that the CSO
controls fail to meet water quality
standards or protect designated uses.
NPDES authorities should commence
enforcement actions against permittees
that have CWA violations due to CSO
discharges during dry weather. In
addition, NPDES authorities should
ensure the implementation of the
minimum technology-based controls
and incorporate a schedule into an
appropriate enforceable mechanism,
with appropriate milestone dates, to.
implement the required long-term CSO
control plan. Schedules for
implementation of the long-term CSO
control plan may be phased based on
the relative importance of adverse
impacts upon water quality standards
and designated uses, and on a
permittee's financial capability.
EPA is developing extensive guidance
to support the Policy and will announce
the availability of the guidances and
other outreach efforts through various
means, as they become available. For
example, EPA is preparing guidance on
the nine minimum controls,
characterization and monitoring of
CSOs, development of long-term CSO
control plans, and financial capability.
Permittees will be expected to comply
with any existing CSO-related
requirements in NPDES permits.
A-3
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Federal Register / Vol. 59, No. 75 / Tuesday. April 19. 1994 / Notices
18689
consent decrees or court orders unless
revised to be consistent with this Policy.
The policy is organized as follows;
I. Introduction
A Purpose and Principles
B. Application of Policy
C Effect on Cumnl CSO Control Efforts
D. Small System Consideration*
E. Implementation Responsibilities
P. Policy Development
IL EPA Objective* for Permittees
A. Overview
B. Implementation of IhtNine Minimum
Controls
C Long-Term CSO Control Plan
1. Charactorizalion, Monitoring, and
Modeling of the Combined Sewer
Systems
2. Public Participation
3. Cons ideratlon of Sens itivo Arms
4. Evaluation of Alternative*
S. Cod/Performance Conilderalion
8. Operational Plan
7. Maximizing Treatment at the Existing
POTWTre«tmenl Plant
8. Implementation Schedule
9. Post-Construction Compliance
Monitoring Program
III. Coordination With State Water Quality
Standards
A. Overview
B. Water Quality Standards Reviews
IV. Expectations for Permitting Authorities
A. Overview
B. NPDES Permit Requirement!
1. Phase 1 Permlla — Requirement* for
Demonstration of the Nine Minimum
Controls and Development of the Long-
Term CSO Control Plan
2. Phase II Permits— Requirements for
Implementation of a Long-Tenn CSO
Control Plan
3. Phtsing Considerations
V. Enforcement and Compliance
A. Overview
B. Enforcement of CSO Dry Weather
Discharge Prohibition
C. Enforcement of Wet Weather CSO
Requirements
1. Enforcement for Compliance With Phase
I Permits
2. Enforcement for Compliance With Phase
II Permit!
D. Penalties
List of Subjects in 40 CFR Put 122
Witer pollution control.
Authorityt Clean Water Act. 33 U.S.C. 1251
Deled: April 8. 1994.
Carol M. Browner,
Administrator.
Combined Sower Overflow (CSO)
Control Policy
/. Introduction
A. Purpose and Principles
The main purposes of this Policy are
to elaborate on EPA's National
Combined Sewer Overflow (CSO)
Control Strategy published on
September B. 1989 at 54 FR 37370 (1989
Strategy) and to expedite compliance
with the requirements of the Clean
Water Act (CWA). While
Implementation of the 1989 Strategy has
resulted in progress toward controlling
CSOs, significant water quality risks
remain.
A combined sewer system (CSS) is a
wastewater collection system owned by
a State or municipality (as defined by
section 502(4) of the CWA) which
conveys sanitary wastewaters (domestic,
commercial and industrial wastewaters)
and storm water through a single-pipe
system to a Publicly Owned Treatment
Works (POTW) Treatment Plant (as
defined In 40 CFR 403.3(p)). A CSO is
the discharge from a CSS at a point prior
to the POTW Treatment Plant. CSOs are
point sources subject to NPDES permit
requirements Including both
technology-based and water quality-
based requirements of the CWA. CSOs
are not subject to secondary treatment
requirements; applicable to POTWs.
CSOs consist of mixtures of domestic
sewage, industrial and commercial
wastewaters, and storm water runoff.
CSOs often contain high levels of
suspended solids, pathogenic
microorganisms, toxic pollutants,
floatable*, nutrients, oxygen-demanding
organic compounds, oil and grease, and
other pollutants. CSOs can cause
exceedances of water quality standards
(WQS). Such exceedajices may pose
risks to human health, threaten aquatic
life and its habitat, and impair the use
and enjoyment of (he Nation's
waterways.
This Policy is Intended to provide
guidance to permittees with CSOs.
National Pollutant Discharge
Elimination System (NPDES) permitting
authorities. State water quality
standards authorities and enforcement
authorities. The purpose of the Policy is
to coordinate the planning, selection.
design and implementation of CSO
management practices and controls to
meet the requirements of the CWA and
to involve the public fully during the
decision making process.
This Policy reiterates the objectives of
the 1989 Strategy:
1. To ensure that If CSOs occur, they are
only as a result of wet weather.
Z. To bring all wet weather CSO
discharge points into compliance with
the technology-based and water
quality-based requirements of the
CWA; and
3. To minimize water quality, aquatic
biota, and human health impacts from
CSOs.
This CSO Control Policy represents a
comprehensive national strategy to
ensure that municipalities, permitting
authorities, water quality standards
authorities and the public engage in a
comprehensive and coordinated
planning effort to achieve cost-effective
CSO controls that ultimately meet
appropriate health and environmental
objectives and require merits. The Policy
recognizes the site-specific nature of
CSOs and their impacts and provides
the necessary flexibility to tailor
controls to local situations. Pour key
principles of the Policy ensure that CSO
controls are cost-effective and meet the
objectives of the CWA. The key
principles are:
1. Providing clear levels of control that
would be presumed to meet
appropriate health and environmental
objectives;
2. Providing sufficient flexibility to
municipalities, especially financially
disadvantaged communities, to
consider the site-specific nature of
CSOs and to determine the most cost-
effective means of reducing pollutants
and meeting CWA objectives and
requirements:
3. Allowing a phased approach to
implementation of CSO controls
considering a community's financial
capability; and
4. Review and revision, as appropriate,
of water quality standards and their
implementation procedures when
developing CSO control plans to
reflect the site-specific wet weather
impacts of CSOs.
This Policy is being Issued in support
of EPA's regulations and policy
initiatives. This Policy is Agency
guidance only and does not establish or
affect legal rights or obligations. It does
not establish a binding norm and It not
finally determinative of the issues
addressed. Agency decisions In any
particular case will be made by applying
the law and regulations on the basis of
specific facts when permits are issued.
The Administration has recommended
that the 1994 amendments to the CWA
endorse this final Policy.
B. Application of Policy
The permitting provisions of this
Policy apply to all CSS* that overflow
as a result of storm water flow,
including snow melt runoff (40 CFR
122.26(b)(13)). Discharges from CSSs
during dry weather are prohibited by
the CWA. Accordingly, the permitting
provisions of this Policy do not apply to
CSOs during dry weather. Dry weather
flow is the flow in a combined sewer
that results from domestic sewage,
groundwater infiltration, commercial
and industrial wastewaters, and any
other non-precipitation related flows
(e.g.. Udal infiltration). In addition to
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the permitting provisions, the
Enforeainont and Compliance section of
this Policy describes an enforcement
initiative being developed for overflows
that occur during dry weather.
Consistent with the 1989 Strategy. 30
States that submitted CSO permitting
strategies have received EPA approval
or, in the case of one State, conditional
approval of its strategy. Stales and EPA
Regional Offices should review these
strategies and negotiate appropriate
revisions to them to implement this
Policy. Permitting authorities are
encouraged to evaluate water pollution
control needs on a watershed
management basis and coordinate CSO
control efforts with other point and
nonpoint source control activities.
C. Effect on Current CSO Control Efforts
EPA recognizes that extensive work
has been done by many Regions, Stales,
and municipalities to abate CSOs. As
such, portions of this Policy may
already have been addressed by
permittees' previous efforts to control
CSOs. Therefore, portions of this Policy
may not apply, as determined by the
permitting authority on a case-by-case
basis, under the following
circumstances:
1. Any permittee that, on the date of
publication of this final Policy, has
completed or substantially completed
construction of CSO control facilities
that are designed to meet WQS and
protect designated uses, and where it
has been determined that WQS are
being or will be attained, is not covered
by the initial planning and construction
provisions in this Policy; however, the
operational plan and post-construction
monitoring provisions continue to
apply. If, after monitoring, it is
determined that WQS are not being
attained, the permittee should be
required to submit a revised CSO
control plan that, once Implemented,
will attain WQS.
2. Any permittee that, on the date of
publication of this final Policy, has
substantially developed or is
implementing a CSO control program
pursuant to an existing permit or
enforcement order, and such program is
considered by the NPDES permitting
authority to be adequate to meet WQS
and protect designated uses and is
reasonably equivalent to the treatment
objectives of this Policy, should
complete those facilities without further
planning activities otherwise expected
by this Policy. Such programs, however,
should be reviewed and modified to be
consistent with the sensitive area,
financial capability, and post-
construction monitoring provisions of
this Policy.
3. Any permittee that has previously
constructed CSO control facilities in an
effort to comply with WQS but has
failed to meet such applicable standards
or to protect designated uses due to
remaining CSOs may receive
consideration for such efforts in future
permits or enforceable orders for long-
term CSO control planning, design and
implementation.
In the case of any ongoing or
substantially completed CSO control
effort, the NPDES permit or other
enforceable mechanism, as appropriate.
should be revised to include all
appropriate permit requirements
consistent with Section IV.B, of this
Policy.
D. Smalt System Considerations
The scope of the long-term CSO
control plan, including the
characterization, monitoring and
modeling, and evaluation of alternatives
portions of this Policy may be difficult
for some small CSSs. At the discretion
of the NPDES Authority, jurisdictions
with populations under 75,000 may not
need to complete each of the formal
steps outlined in Section II.C. of this
Policy, but should be required through
their permits or other enforceable
mechanisms to comply with the nine
minimum controls (H.B). public
participation (It.C.2). and sensitive areas
(II,C 3) portions of this Policy. In
addition, the permittee may propose to
implement any of the criteria contained
in this Policy for evaluation of
alternatives described in II.C.4.
Following approval of the proposed
plan, such jurisdictions should
construct the control projects and
propose a monitoring program sufficient
to determine whether WQS are attained
and designated uses are protected.
In developing long-term CSO control
plans based on the small system
considerations discussed in the
preceding paragraph, permittees are
encouraged to discuss the scope of their
long-term CSO control plan with the
WQS authority and the NPDES
authority. These discussions will ensure
that the plan includes sufficient
information to enable the permitting
authority to identify the appropriate
CSO control-!.
E. Implementation Responsibilities
NPDES authorities (authorized States
or EPA Regional Offices, as appropriate)
are responsible for implementing this
Policy, It is their responsibility to assure
that CSO permittees develop long-term
CSO control plans and that NPDES
permits meet the requirements of the
CWA. Further, they are responsible for
coordinating the review of the long-term
CSO control plan and the development
of the permit with the WQS authority to
determine if revisions to the WQS are
appropriate. In addition, they should
determine the appropriate vehicle (i.e.,
permit reissuance, information request
under CWA section 308 or State
equivalent or enforcement action) to
ensure that compliance with the CWA is
achieved as soon as practicable.
Permittees are responsible for
documenting the implementation of the
nine minimum controls and developing
and implementing a long-term CSO
control plan, as described in this Policy.
EPA recognizes that financial
considerations are a major factor
affecting the implementation of CSO
controls. For that reason, this Policy
allows consideration of a permittee's
financial capability in connection with
the long-term CSO control planning
effort, WQS review, and negotiation of
enforceable schedules. However, each
permittee is ultimately responsible for
aggressively pursuing financial
arrangements for the implementation of
its long-term CSO control plan. As part
of this effort, communities should apply
to their State Revolving Fund program.
or other assistance programs as
appropriate, for financial assistance.
EPA and the States will undertake
action to assure that all permittees with
CSSs are subject to a consistent review
in the permit development process.
have permit requirements that achieve
compliance with the CWA, and are
subject to enforceable schedules that
require the earliest practicable
compliance date considering physical
and financial feasibility.
F. Policy Development
This Policy devotes a separate section
to each step involved in developing and
implementing CSO controls. This is not
to Imply that each function occurs
separately. Rather, the entire process
surrounding CSO controls, community
planning. WQS and permit
development/revision, enforcement/
compliance actions and public
participation must be coordinated to
control CSOs effectively. Permittees and
permitting authorities are encouraged to
consider innovative and alternative
approaches and technologies that
achieve the objectives of this Policy and
the CWA.
In developing this Policy. EPA has
included information on what
responsible parties are expected to
accomplish. Subsequent documents will
provide additional guidance on how the
objectives of this Policy should be met.
These documents will provide further
guidance on: CSO permit writing, the
nine minimum controls, long-term CSO
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18691
control plans, financial capability,
sewer system characterization and
receiving water monitoring and
modeling, and application of WQS to
CSO-impacted waters. For most CSO
control efforts however, sufficient detail
has been included In this Policy to
begin immediate implementation of its
provisions,
U. EPA Objectives for Permittees
A. Overview
Permittees with CSSs that have CSGs
should immediately undertake a process
to accurately characterize their sewer
systems, to demonstrate implementation
of the nine minimum controls, and to
develop a long-term CSO control plan.
B. Implementation of the Nine
Minimum Controls
Permittees with CSOs should submit
appropriate documentation
demonstrating implementation of the
nine minimum controls, including any
proposed schedules for completing
minor construction activities. The nine
minimum controls are:
1. Proper operation and regular
maintenance programs for the sewer
system and the CSOs;
2. Maximum use of the collection
system for storage;
3. Review and modification of
pretreatment requirements to assure
CSO impacts are minimized;
4. Maximization of flow to the POTW
for treatment;
S. Prohibition of CSOs during dry
weather,
6. Control of solid and floatable
materials in CSOs;
7. Pollution prevention:
8. Public notification to ensure that the
public receives adequate notification
of CSO occurrences and CSO impacts;
and
9. Monitoring to effectively characterize
CSO impacts and the efficacy of CSO
controls.
Selection and implementation of
actual control measures should be based
on site-specific considerations including
the specific CSS's characteristics
discussed under the sewer system
characterization and monitoring
portions of this Policy. Documentation
of the nine minimum controls may
include operation and maintenance
plans, revised sewer use ordinances for
industrial users, sewer system
inspection reports, infiltration/inflow
studies, pollution prevention programs,
public notification plans, and facility
plans for maximizing the capacities of
the existing collection, storage and
treatment systems, as well as contracts
and schedules for minor construction
programs for Improving the existing
system's operation. The permittee
should also submit any information or
data on the degree to which the nine
minimum controls achieve compliance
with water quality standards. These data
and Information should include results
made available through monitoring and
modeling activities done in conjunction
with the development of the long-term
CSO control plan described in this
Policy.
This documentation should be
submitted as soon as practicable, but no
later than two years after the
requirement la submit such
documentation is included in an NPDES
permit or other enforceable mechanism.
Implementation of the nine minimum
controls with appropriate
documentation should be completed as
soon as practicable but no later than
January 1.1997. These dates should be
included in an appropriate enforceable
mechanism.
Because the CWA requires immediate
compliance with technology-based
controls (section 301 (bl), which on a
Best Professional Judgment basis should
include the nine minimum controls, a
compliance schedule for implementing
the nine minimum controls, If
necessary, should be included in an
appropriate enforceable mechanism.
C. Long-Term CSO Control Plan
Permittees with CSOs are responsible
for developing and implementing long-
term CSO control plans that will
ultimately result in compliance with the
requirements of the CWA. The long-
term plans should consider the site-
specific nature of CSOs and evaluate the
cost effectiveness of a range of control
options/strategies. The development of
the long-term CSO control plan and its
subsequent implementation should also
be coordinated with the NPDES
authority and the State authority
responsible for reviewing and revising
the State's WQS. The selected controls
should be designed to allow cost
effective expansion or cost effective
retrofitting if additional controls are
subsequently determined to be
necessary to meet WQS, including
existing and designated uses.
This policy identifies EPA's major
objectives for the long-term CSO control
plan. Permittees should develop and
submit this long-term CSO control plan
as soon as practicable, but generally
within two years after the date of the
NPDES permit provision. Section 308
information request, or enforcement
action requiring the permittee to
develop the plan. NPDES authorities
may establish a longer timetable for
completion of the long-term CSO
control plan on a case-by-case basis to
account for site-specific factors which
may influence the complexity of the
planning process. Once agreed upon,
these dates should be included in on
appropriate enforceable mechanism.
EPA expects each long-term CSO
control plan to utilize appropriate
information to address the following
minimum elements. The Plan should
also include both fixed-date project
implementation schedules (which may
be phased) and a financing plan to
design and construct the project as soon
as practicable. The minimum elements
of the long-term CSO control plan are
described below.
1. Characterization, Monitoring, and
Modeling of the Combined Sewer
System
In order to design a CSO control plan
adequate to meet the requirements of
the CWA, a permittee should have a
thorough understanding of its sewer
system, the response of the system to
various precipitation events, the
characteristics of the overflows, and the
water quality Impacts that result from
CSOs. The permittee should adequately
characterize through monitoring,
modeling, and other means as
appropriate, for a range of storm events,
the response of its sewer system to wet
weather events including the number,
location and frequency of CSOs,
volume, concentration and mass of
pollutants discharged and the impacts
of the CSOs on the receiving waters and
their designated uses. The permittee
may need to consider information on
the contribution and importance of
other pollution sources in order to
develop a final plan designed to meet
water quality standards. The purpose of
the system characterization, monitoring
and modeling program initially is to
assist the permittee in developing
appropriate measures to implement the
nine minimum controls and, if
necessary, to support development of
the long-term CSO control plan. The
monitoring and modeling data also will
be used to evaluate the expected
effectiveness of both the nine minimum
controls and. if necessary, the long-term
CSO controls, to meet WQS.
The major elements of a sewer system
characterization are described below.
a. Rainfall Records—The permittee
should examine the complete rainfall
record for the geographic ana of its
existing CSS using sound statistical
procedures and best available data. The
permittee should evaluate flow
variations in the receiving water body to
correlate between CSOs and receiving
water conditions.
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b. Combined Sewer System
Characterization—The permittee should
evaluate the nature and extent of it*
sewer system through evaluation of
available sewer system records. Geld
inspections and other activities
necessary to understand the number.
location and frequency of overflows and
their location relative to sensitive areas
and to pollution sources in the
collection system, such as indirect
significant industrial users.
c, CSO Monitoring—The permittee
should develop a comprehensive,
representative monitoring program that
measures the frequency, duration, flow
rate, volume and pollutant
concentration of CSO discharges and
assesses the impact of the CSOs on the
receiving waters. The monitoring
program should include necessary CSO
effluent and ambient in-stream
monitoring and. where appropriate.
other monitoring protocols such as
biological assessment, toxicity testing
and sediment sampling. Monitoring
parameters should include, for example.
oxygen demanding pollutants, nutrients.
toxic pollutants, sediment
contaminants, pathogens.
bacteriological indicators (e.g.,
Enlerococcus, E. Coli), and toxicity. A
representative sample of overflow
points can be selected that is sufficient
to allow characterization of CSO
discharges and their water quality
Impacts and to facilitate evaluation of
control plan alternatives.
d. Modeling—Modeling of a sewer
system is recognized as a valuable tool
for predicting sewer system response to
various wet weather events and
assessing water quality impacts when
evaluating different control strategies
and alternatives. EPA supports the
proper and effective use of models,
where appropriate, in the evaluation of
the nine minimum controls and the
development of the long-term CSO
control plan. It is also recognized that
there are many models which may be
used to do this. These models range
from simple to complex. Having
decided to use a model, the permittee
should base its choice of a model on the
characteristics of its sewer system, the
number and location of overflow points,
and the sensitivity of the receiving
water body to the CSO discharges. Use
of models should include appropriate
calibration and verification with Geld
measurements. The sophistication of the
model should relate to the complexity of
the system to be modeled and to the
information needs associated with
evaluation of CSO control options and
water quality impacts. EPA believes that
continuous simulation models, using
historical rainfall data, may be the best
way to model sewer systems, CSOs. and
their impact!. Because of the iterative
nature of modeling sewer systems,
CSOs. and their impacts, monitoring
and modeling efforts are complementary
and should be coordinated.
2. Public Participation
In developing its long-term CSO
control plan, the permittee will employ
a public participation process that
actively involves the affected public in
the decision-making to select the long-
term CSO controls. The affected public
includes rate payers, industrial users of
the sewer system, persons who reside
downstream from the CSOs, persons
who use and enjoy these downstream
waters, and any other interested
persons.
3. Consideration of Sensitive Areas
EPA expects a permittee's long-term
CSO control plan to give the highest
priority to controlling overflows to
sensitive areas. Sensitive areas, as
determined by the NPDES authority in
coordination with State and Federal
agencies, as appropriate, include
designated Outstanding National
Resource Waters, National Marine
Sanctuaries, waters with threatened or
endangered species and their habitat.
waters with primary contact recreation.
public drinking water intakes or their
designated protection areas, and
shellfish beds. For such areas, the long-
term CSO control plan should:
a. Prohibit new or significantly
increased overflows;
b. i. Eliminate or relocate overflows
that discharge to sensitive areas
wherever physically possible and
economically achievable, except where
elimination or relocation would provide
less environmental protection than
additional treatment; or
ii. Where elimination or relocation is
not physically possible and
economically achievable, or would
provide less environmental protection
than additional treatment, provide the
level of treatment for remaining
overflows deemed necessary to meet
WQS for full protection of existing and
designated uses, hi any event, the level
of control should not be less than those
described in Evaluation of Alternatives
below; and
C Where elimination or relocation has
been proven not to be physically
possible and economically achievable,
permitting authorities should require,
for each subsequent permit term, a
reassessment based on new or improved
techniques to eliminate or relocate, or
on changed circumstances that
influence economic achievability.
4. Evaluation of Alternatives
EPA expects the long-term CSO
control plan to consider a reasonable
range of alternatives. The plan should.
for example, evaluate controls that
would be necessary to achieve zero
overflow events per year, an average of
one to three, four to seven, and eight to
twelve overflow events per year.
Alternatively, the long-term plan could
evaluate controls that achieve 100%
capture, 90% capture. 85% capture,
80% capture, and 75% capture for
treatment The long-term control plan
should also consider expansion of
POTW secondary and primary capacity
in the CSO abatement alternative
analysis. The analysis of alternatives
should be sufficient to make a
reasonable assessment of cost and
performance as described in Section
n.CS. Because the final long-term CSO
control plan will become the basis for
NPDES permit limits and requirements,
the selected controls should be
sufficient to meet CVVA requirements.
In addition to considering sensitive
areas, the long-term CSO control plan
should adopt one of the following
approaches:
a. "Presumption" Approach
A program that meets any of the
criteria listed below would be presumed
to provide an adequate level of control
to meet the water quality-based
requirements of the CVVA. provided the
permitting authority determines that
such presumption Is reasonable in light
of the data and analysis conducted in
the characterization, monitoring, and
modeling of the system and the
consideration of sensitive areas
described above. These criteria are
provided because data and modeling of
wet weather events often do not give a
clear picture of the level of CSO controls
necessary to protect WQS.
i. No more than an average of four
overflow events per year, provided that
the permitting authority may allow up
to two additional overflow events per
year. For the purpose of this criterion,
an overflow event is one or more
overflows from a CSS as the result of a
precipitation event that does Dot receive
the minimum treatment specified
below; or
ii. The elimination or the capture for
treatment of no less than 85% by
volume of the combined sewage
collected in the CSS during
precipitation events on a system-wide
annual average basis; or
iU. The elimination or removal of no
less than the mass of the pollutants,
identified as causing water quality
impairment through the sewer system
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characterization, monitoring, and
modeling effort, for the volumes that
would be eliminated or captured for
treatment under paragraph ii. above.
Combined sewer flows remaining after
implementation of the nine minimum
controls and within the criteria
specified at II.C.4.a.i or ii. should
receive a minimum of:
• Primary clarification (Removal of
floatables and settleable solids may be
achieved by any combination of
treatment technologies or methods that
are shown to be equivalent to primary
clarification.):
• Solids and floatables disposal; and
• Disinfection of effluent, if
necessary, to meet WQS. protect
designated uses and protect human
health, including removal of harmful
disinfection chemical residuals, where
necessary.
b. "Demonstration" Approach
A permittee may demonstrate that a
selected control program, though not
meeting the criteria specified in II.C.4.a.
above is adequate to meet the water
quality-based requirements of the CWA.
To be a successful demonstration, the
permittee should demonstrate each of
the following;
i. The planned control program is
adequate to meet WQS and protect
designated uses, unless WQS or uses
cannot be met as a result of natural
background conditions or pollution
sources other than CSOs;
ii. The CSO discharges remaining
after implementation of the planned
control program will not preclude the
attainment of WQS or the receiving
waters' designated uses or contribute to
their impairment. Where WQS and
designated uses are not met in part
because of natural background
conditions or pollution sources other
than CSOs, a total maximum daily load,
including a wasleload allocation and a
load allocation, or other means should
be used to apportion pollutant loads:
ill. The planned control program will
provide the maximum pollution
reduction benefits reasonably attainable;
and
iv. The planned control program is
designed to allow cost effective
expansion or cost effective retrofitting if
additional controls are subsequently
determined to be necessary to meet
WQS or designated uses.
S. Cost/Performance Considerations
The permittee should develop
appropriate cost/performance curves to
demonstrate the relationships among a
comprehensive set of reasonable control
alternatives that correspond to the
different ranges specified in Section
n.C.4. This should include an analysis
to determine where the increment of
pollution reduction achieved in the
receiving water diminishes compared to
the increased costs. This analysis, often
known as knee of the curve, should be
among the considerations used to help
guide selection of controls.
6. Operational Plan
After agreement between the
permittee and NPDES authority on the
necessary CSO controls to be
implemented under the long-term CSO
control plan, the permittee should
revise the operation and maintenance
program developed as part of the nine
minimum controls to include the
agreed-upon long-term CSO controls.
The revised operation and maintenance
program should maximize the removal
of pollutants during and after each
precipitation event using all available
facilities within the collection and
treatment system. For any flows in
excess of the criteria specified at
Il.C 4.a,i.. ii. or iii and not receiving the
treatment specified in Il.C.4.H. the
operational plan should ensure that
such flows receive treatment to the
greatest extent practicable.
7. Maximizing Treatment at the Existing
POTW Treatment Plant
In some communities. POTW
treatment plants incy have primary
treatment capacity in excess of their
secondary treatment capacity. One
effective strategy to abate pollution
resulting from CSOs is to maximize the
delivery of flows during wet weather to
the POTW treatment plant for treatment.
Delivering these flows can have two
significant water quality benefits: First,
increased flows during wet weather to
the POTW treatment plant may enable
the permittee to eliminate or minimize
overflows to sensitive areas: second, this
would maximize the use of available
POTW facilities for wet weather flows
and would ensure that combined sewer
flows receive at least primary treatment
prior to discharge.
Under EPA regulations, the
intentional diversion of waste streams
from any portion of a treatment facility.
including secondary treatment, is a
bypass. EPA bypass regulations at 40
CFR 122.41(m) allow for a facility to
bypass some or all the flow from its
treatment process under specified
limited circumstances. Under the
regulation, the permittee must show that
the bypass was unavoidable to prevent
loss of life, personal injury or severe
property damage, that there was no
feasible alternative to the bypass and
that the permittee submitted the
required notices. In addition, the
regulation provides that a bypass may
be approved only after consideration of
adverse effects.
Normally, it is the responsibility of
the permittee to document, on a case-by-
base basis, compliance with 40 CFR
122.41 (m) in order to bypass flows
legally. For some CSO-related permits.
the Study of feasible alternatives in the
control plan may provide sufficient
support for the permit record and for
approval of a CSO-related bypass in the
permit itself, and to define the specific
parameters under which a bypass can
legally occur. For approval of a CSO-
related bypass, the long-term CSO
control plan, at a minimum, should
provide justification for the cut-off point
at which the flow will be diverted from
the secondary treatment portion of the
treatment plant, and provide a benefit-
cost analysis demonstrating that
conveyance of wet weather flow to the
POTW for primary treatment is more
beneficial than other CSO abatement
alternatives such as storage and pump
back for secondary treatment, sewer
separation, or satellite treatment. Such a
permit must define under what specific
wet weather conditions a CSO-related
bypass is allowed end also specify what
treatment or what monitoring, and
effluent limitations and requirements
apply to the bypass flow. The permit
should also provide that approval for
the CSO-related bypass will be reviewed
and may be modified or terminated if
there is a substantial increase in the
volume or character of pollutants being
introduced to the POTW. The CSO-
related bypass provision in the permit
should also make it clear that all wet
weather flows passing the headworks of
the POTW treatment plant will receive
at least primary clarification and solids
and floatables removal and disposal,
and disinfection, where necessary, and
any other treatment that can reasonably
be provided.
Under this approach, EPA would
allow a permit to authorize a CSO-
related bypass of the secondary
treatment portion of the POTW
treatment plant for combined sewer
flows in certain identified
circumstances. This provision would
apply only to those situations where the
POTW would ordinarily meet the
requirements of 40 CFR 12Z.41(m) as
evaluated on a case-by-case basis.
Therefore, there must be sufficient data
in the administrative record (reflected in
the permit fact sheet or statement of
basis] supporting all the requirements in
40 CFR 122.41(m)(4) for approval of an
anticipated bypass.
For the purposes of applying this
regulation to CSO permittees, "severe
property damage" could include
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situations where flows above a certain
level wash out the POTW's secondary
treatment system. EPA further believes
that the feasible alternatives
requirement of the regulation can be met
if the record shows that the secondary
treatment system is properly operated
and maintained, that the system has
been designed to meet secondary limits
for flows greater than the peak dry
weather flow, plus an appropriate
quantity of wet weather flow, and thai
it is either technically or financially
infoasible to provide secondary
treatment at the existing facilities for
greater amounts of wet weather flow.
The feasible alternative analysis should
include, for example, consideration of
enhanced primary treatment (e.g.,
chemical addition] and non-biological
secondary treatment. Other bases
supporting a finding of no feasible
alternative may also be available on a
case-by-case basis. As part of its
consideration of possible adverse effects
resulting from the bypass, the
permitting authority should also ensure
that the bypass will not cause
exceedances of WQS.
This Policy does not address the
appropriateness at approving
anticipated bypasses through NPDES
permits in advance outside the CSO
context.
8. Implementation Schedule
The permittee should include all
pertinent information in the long term
control plan necessary to develop the
construction and financing schedule for
implementation of CSO controls.
Schedules for implementation of the
CSO controls may be phased based on
the relative importance of adverse
impact* upon WQS and designated
uses, priority projects identified in the
long-term plan, and on a permittee's
financial capability.
Construction phasing should
consider
a. Eliminating overflows that
discharge to sensitive areas as the
highest priority;
b. Use impairment;
c. The permittee's financial capability
including consideration of such factors
as:
i. Median household income;
ii. Total annual waste water and CSO
control costs per household as a percent
of median household income;
iii. Overall net debt as a percent of
full market property value:
iv. Property tax revenues as a percent
of full market property value;
v. Property tax collection rate;
vi. Unemployment; and
vii. Bond rating:
d. Grant and loan availability,
e. Previous and current residential,
commercial and industrial sewer user
fees and rate structures; and
f. Other viable funding mechanisms
and sources of financing.
9. Post-Construction Compliance
Monitoring Program
The selected CSO controls should
include a post-construction water
quality monitoring program adequate to
verify compliance with water quality
standard* and protection of designated
uses as well as to ascertain the
effectiveness of CSO controls. This
water quality compliance monitoring
program should include a plan to be
approved by the NPDES authority that
details the monitoring protocols to be
followed, including the necessary
effluent and ambient monitoring and,
where appropriate, other monitoring
protocols such as biological
assessments, whole effluent toxicity
testing, and sediment sampling.
/W. Coordination With State Water
Quality Standards
A. Overview
WQS are State adopted, or Federally
promulgated rules which serve as the
goals for the water body and the legal
basis for the water quality-based NPDES
permit requirements under the CWA,
WQS consist of uses which States
designate for their water bodies, criteria
to protect the uses, an anti-degradation
policy to protect the water quality
improvements gained and other policies
affecting the implementation of the
standards. A primary objective of the
long-term CSO control plan is to meet
WQS, including the designated uses
through reducing risks to human health
and the environment by eliminating,
relocating or controlling CSOs to the
affected waters.
State WQS authorities, NPDES
authorities, EPA regional offices,
permittees, and the public should meet
early and frequently throughout the
long-term CSO control planning
process. Development of the long-term
plan should be coordinated with the
review and appropriate revision of WQS
and implementation procedures on
CSO-impacted waters to ensure that the
long-term controls will be sufficient to
meet weter quality standards. As part of
these meetings, participants should
agree on the data, information and
analyses needed to support the
development of the long-term CSO
control plan and the review of
applicable WQS, and implementation
procedures, if appropriate. Agreements
should be reached on the monitoring
protocols and models that will be used
to evaluate the water quality impacts of
the overflow), to analyze the
alt ui nubility of the WQS and to
determine the water quality-based
requirements far the permit. Many
opportunities exist for permittees and
Stales to share information as control
programs are developed and as WQS are
reviewed. Such information should
assist States in determining the need for
revisions to WQS and implementation
procedures to better reflect the site-
specific wet weather impacts of CSOs.
Coordinating the development of the
long-term CSO control plan and the
review of the WQS and implementation
procedures provides greater assurance
that the long-term control plan selected
and the limits and requirements
included in the NPDES permit will be
sufficient to meet WQS and to comply
with sections 30l(b)(l)(C) and 40Z(a)(Z)
of the CWA.
EPA encourages States and permittees
jointly to sponsor workshops for the
affected public in the development of
the long-term CSO control plan and
during the development of appropriate
revisions to WQS for CSO-impacted
waters. Workshops provide a forum for
including the public in discussions of
the implications of the proposed long-
term CSO control plan on the water
quality and uses for the receiving water.
B. Water Quality Standards Reviews
The CWA requires States to
periodically, but at least once every
three years, hold public hearings for the
purpose of reviewing applicable water
quality standards and, as appropriate,
modifying and adopting standards.
States must provide the public an
opportunity to comment on any
proposed revision to water quality
standards and all revisions must be
submitted to EPA for review and
approval.
EPA regulations and guidance provide
States with the flexibility to adapt their
WQS, and implementation procedures
to reflect site-specific conditions
Including those related to CSOs. For
example, a State may adopt site-specific
criteria for a particular pollutant if the
Slate determines that the site-specific
criteria fully protects the designated use
(40 CFR 131.11). In addition, the
regulations at 40 CFR 131 10(g), (h). and
(j) specify when and how a designated
use may be modified. A State may
remove a designated use from its water
quality standards only if the designated
use is not an existing use. An existing
use is a use actually attained in the
water body on or after November 28,
197S. Furthermore, a State may not
remove a designated use that will be
attained by implementing the
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18695
technology-baaed effluent limits
required under sections 301(b) and 306
of the CWA and by implementing co*l-
effective and reasonable best
management practices for nonpoint
source controls. Thus, if a State has a
reasonable basis to determine that the
current designated use could be attained
after implementation of the technology-
based controls of the CWA, then the use
could not be removed.
In determining whether a use is
attainable and prior to removing a
designated use. States must conduct and
submit to EPA a use attainability
analysis. A use attainability analysis is
a structured scientific assessment of the
factors affecting the use, including the
physical, chemical, biological, and
economic factors described in 40 CFR
131.10(g). As part of the analysis. States
should evaluate whether the designated
use could be attained if CSO controls
were implemented. For example, States
should examine if sediment loadings
from CSOs could be reduced so as not
to bury spawning beds, or if
biochemical oxygen demanding material
In the effluent or the toxicity of the
effluent could be corrected so as to
reduce the acute or chronic
physiological stress on or
bioaccumulation potential of aquatic
organisms.
In reviewing the attainability of their
WQS and the applicability of their
implementation procedures to CSO-
impacted waters, States are encouraged
to define more explicitly their
recreational and aquatic life uses and
then, if appropriate, modify the criteria
accordingly to protect the designated
uses.
Another option is for States to adopt
partial uses by defining when primary
contact recreation such as swimming
does not exist, such as during certain
seasons of the year in northern climates
or during a particular type of storm
event, hi making such adjustments to
their uses. States must ensure that
downstream uses are protected, and that
during other seasons or after the storm
event has passed, the use is fully
protected.
In addition to defining recreational
uses with greater specificity. States are
also encouraged to define the aquatic
uses more precisely. Rather than
"aquatic life use protection," States
should consider defining the type of
fishery to be protected such as a cold
water fishery (e.g., trout or salmon) or a
warm weather fishery (e.g., bluegill or
large mouth bass). Explicitly defining
the type of fishery to be protected may
assist the permittee in enlisting the
support of citizens for a CSO control
plan.
A water quality standard variance
may be appropriate, in limited
circumstances on CSO-impacled waters,
where the State is uncertain as to
whether a standard can be attained and
time is needed for the State to conduct
additional analyses on the attainability
of the standard. Variances are short-term
modifications in water quality
standards. Subject to EPA approval.
States, with their own statutory
authority, may grant a variance to a
specific discharger for a specific
pollutant. The justification fora
variance is similar to that required for
a permanent change in the standard,
although the showings needed are less
rigorous. Variances are also subject to
public participation requirements of the
water quality standards and permits
programs and are reviewable generally
every three years. A variance allows the
CSO permit (o be written lo meet the
"modified" water quality standard as
analyses are conducted and as progress
is made to Improve water quality.
Justifications for variances are the
same as those identified In 40 CFR
131 .lUfg) for modifications in uses.
States must provide an opportunity for
public review and comment on all
variances. If States use the permit as the
vehicle to grant the variance, notice of
the permit must clearly slate that the
variance modifies the State's water
quality standards. If the variance is
approved, the State appends the
variance to the Slate's standards and
reviews the variance every three years.
IV. Expectations for Permitting
Authorities
A. Overview
CSOs are point sources subject to
NPDES permit requirements including
both technology-based and water
quality-based requirements of the CWA.
CSOs are not subject to secondary
treatment regulations applicable to
publicly owned treatment works
(Montgomery Environmental Coalition
vs. Costle. 646 F.2d 56fl (D.C. Cir.
1980)).
All permits for CSOs should require
the nine minimum controls as a
minimum best available technology
economically achievable and best
conventional technology (BAT/BCT)
established on a best professional
judgment (BPT) basis by the permitting
authority (40 CFR 125.3). Water quality-
based requirements are to be established
based on applicable water quality
standards.
This policy establishes B uniform,
nationally consistent approach to
developing and issuing NPDES permits
to permittees with CSOs. Permits for
CSOs should be developed and issued
expeditiously A single, system-wide
permit generally should be issued for all
discharges, including CSOs, from a CSS
operated by a single authority. When
different parts of a single CSS are
operated by more than one authority,
permits issued to each authority should
generally require joint preparation and
implementation of the elements of this
Policy and should specifically define
the responsibilities and duties of each
authority. Permittees should be required
to coordinate system-wide
implementation of the nine minimum
controls and the development and
implementation of the long-term CSO
control plan.
The individual authorities are
responsible for their own discharges and
should cooperate with the permittee for
the POTW receiving the flows from the
CSS. When a CSO is permitted
separately from the POTW. both permits
should be cross-referenced for
informational purposes.
EPA Regions and Slates should
review the CSO permitting priorities
established in the State CSO Permitting
Strategies developed in response to the
1989 Strategy. Regions and Slates may
elect to revise these previous priorities.
In setting permitting priorities, Regions
and States should not just focus on
those permittees that have initiated
monitoring programs. When setting
priorities, Regions and States should
consider, for example, the known or
potential impact of CSOs on sensitive
areas, and the extent of upstream
industrial user discharges to the CSS.
During the permittee's development
of the long-term CSO control plan, the
permit writer should promote
coordination between the permittee and
State WQS authority in connection with
possible WQS revisions. Once the
permittee has completed development
of the long-term CSO control plan and
has coordinated with the permitting
authority the selection of the controls
necessary to meet the requirements of
the CWA. the permitting authority
should include in an appropriate
enforceable mechanism, requirements
for implementation of the long-term
CSO control plan, including conditions
for water quality monitoring and
operation and maintenance.
B. NPDES Permit Requirements
Following are the major elements of
NPDES permits to implement this
Policy and ensure protection of water
quality.
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1. Phase I Permits—Requirements for
Demonstration of Implementation of the
Nine Minimum Controls and
Development of the Long-Term CSO
Control Plan
In the Phase I permit Issued/modified
to reflect this Policy, the NPDES
authority should at least require
permittees to:
a. Immediately implement BAT/BCT.
which at a minimum includes the nine
minimum controls, as determined on a
HP) basis by the permitting authority:
b. Develop and submit a report
documenting the implementation of the
nine minimum controls within two
years of permit issuance/modification;
c. Compiy with applicable WQS. no
later than the date allowed under the
State's WQS, expressed in the form of a
narrative limitation; and
d. develop and submit, consistent
with this Policy and based on a
schedule in an appropriate enforceable
mechanism, a long-term CSO control
plan as soon as practicable, but
generally within two years after the
effective date of the permit issuance/
modification. However, permitting
authorities may establish a longer
timetable for completion of the long-
term CSO control plan on a case-by-case
basis to account for site-specific factors
that may influence the complexity of the
planning process.
The NPDES authority should include
compliance dates on the fastest
practicable schedule for each of the nine
minimum controls in an appropriate
enforceable mechanism issued in
conjunction with the Phase I permit.
The use of enforceable orders is
necessary unless Congress amends the
CWA. All orders should require
compliance with the nine minimum
controls no later than January 1,1997.
Z. Phase II Permits—Requirements for
Implementation of a Long-Term CSO
Control Plan
Once the permittee has completed
development of the long-term CSO
control plan and the selection of the
controls necessary to meet CWA
requirements has been coordinated with
the permitting and WQS authorities, the
permitting authority should include, in
an appropriate enforceable mechanism,
requirements for implementation of the
long-term CSO control plan as soon as
practicable. Where the permittee has
selected controls based on the
"presumption" approach described in
Section I1.C.4. the permitting authority
must have determined that the
presumption that such level of
treatment will achieve water quality
standards is reasonable in light of the
data and analysis conducted under this
Policy. The Phase II permit should
contain:
a. Requirements to implement the
technology-based controls including the
nine minimum controls determined on
a BPJ basis:
b. Narrative requirements which
insure that the selected CSO controls are
implemented, operated and maintained
as described in the long-term CSO
control plan;
c. Water quality-based effluent limits
under 40 CFR 122.44(d)(l) and
122.44(k), requiring, at a minimum.
compliance with, no later than the date
allowed under the State's WQS, the
numeric performance standards for the
selected CSO controls, based on average
design conditions specifying at least one
of the following:
i. A maximum number of overflow
events per year for specified design
conditions consistent with II.C.4.a.i: or
ii. A minimum percentage capture of
combined sewage by volume for
treatment under specified design
conditions consistent with Il.C.l.a.ii; or
iii. A minimum removal of the mass
of pollutants discharged for specified
design conditions consistent with
ll.C.4.a.iii; or
iv. performance standards and
requirements that are consistent with
H.C.4.b. of the Policy.
d. A requirement to implement, with
an established schedule, the approved
post-construction water quality
assessment program including
requirements to monitor and collect
sufficient information to demonstrate
compliance with WQS and protection of
designated uses as well as to determine
the effectiveness of CSO controls.
e. A requirement to reassess overflows
to sensitive areas in those cases where
elimination or relocation of the
overflows is not physically possible and
economically achievable. The
reassessment should be based on
consideration of new or improved
techniques to eliminate or relocate
overflows or changed circumstances
that influence economic achievability:
f. Conditions establishing
requirements for maximizing the
treatment of wet weather flows at the
POTVV treatment plant, as appropriate,
consistent with Section D.C.7. of this
Policy;
g. A reopener clause authorizing the
NPDES authority to reopen and modify
the permit upon determination that the
CSO controls fail to meet WQS or
protect designated uses. Upon such
determination, the NPDES authority
should promptly notify the permittee
and proceed to modify or reissue the
permit. The permittee should be
required to develop, submit and
implement, as soon as practicable, a
revised CSO control plan which
contains additional controls to meet
WQS and designated uses. If the Initial
CSO control plan was approved under
the demonstration provision of Section
Il.C.4.b., the revised plan, at a
minimum, should provide for controls
that satisfy one of the criteria in Section
1I.C.4.B. unless the permittee
demonstrates that the revised plan is
clearly adequate to meet WQS at a lower
cost and it is shown that the additional
controls resulting from the criteria in
Section II.C.4.8. will not result in a
greater overall improvement in water
quality.
Unless the permittee can comply with
all of the requirements of the Phase II
permit, the NPDES authority should
include, in an enforceable mechanism,
compliance dates on the fastest
practicable schedule for those activities
directly related to meeting the
requirements of the CWA. For major
permittees, the compliance schedule
should be placed in a judicial order.
Proper compliance with the schedule
for implementing the controls
recommended in the long-term CSO
control plan constitutes compliance
with the elements of this Policy
concerning planning and
implementation of a long term CSO
remedy.
3. Phasing Considerations
implementation of CSO controls may
be phased based on the relative
importance of and adverse impacts
upon WQS and designated uses, as well
as the permittee's financial capability
and its previous efforts to control CSOs.
The NPDES authority should evaluate
the proposed implementation schedule
and construction phasing discussed in
Section U.C.8. of this Policy. The permit
should require compliance with the
controls proposed in the long-term CSO
control plan no later than the applicable
deadline(s) under the CWA or State law.
If compliance with the Phase II permit
is not possible, an enforceable schedule.
consistent with the Enforcement and
Compliance Section of this Policy,
should be issued in conjunction with
the Phase II permit which specifies the
schedule and milestones for
implementation of the long-term CSO
control plan.
V. Enforcement and Compliance
A. Overview
It is important that permittees act
immediately to take the necessary steps
to comply with the CWA. The CSO
enforcement effort will commence with
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18697
an Initiative to address CSOs that
discharge during dry weather, followed
by an enforcement effort in conjunction
with permitting CSOs discussed earlier
In this Policy. Success of the
enforcement effort will depend in large
part upon expeditious action by NPDES
authorities in issu ing enforceable
permits that include requirements both
for the nine minimum controls and for
compliance with all other requirements
of the CWA. Priority for enforcement
actions should be set based on
environmental impacts or sensitive
areas affected by CSOs.
As a further inducement for
permittees to cooperate with this
process, EPA is prepared to exercise its
enforcement discretion in determining
whether or not to seek civil penalties for
past CSO violations if permittees meet
the objectives and schedules of this
Policy and do not have CSOs during dry
weather.
B. Enforcement of CSO Dry Weather
Discharge Prohibition
EPA intends to commence
immediately an enforcement Initiative
against CSO permittees which have
CWA violations due to CSOs during dry
weather. Discharges during dry weather
have always been prohibited by the
NPDES program. Such discharges can
create serious public health and water
quality problems. EPA will use its CWA
Section 308 monitoring, reporting, and
inspection authorities, together with
NPDES State authorities, to locate these
violations, and to determine their
causes. Appropriate remedies and
penalties will be sought for CSOs during
dry weather. EPA will provide NPDES
authorities more specific guidance on
this enforcement initiative separately.
C Enforcement of Wet Weather CSO
Requirements
Under the CWA, EPA can use several
enforcement options to address
permittees with CSOs. Those options
directly applicable to this Policy are
section 308 Information Requests,
section 309(a) Administrative Orders,
section 309(g) Administrative Penalty
Orders, section 309 {b) and (d) Civil
Judicial Actions, and section 504
Emergency Powers. NPDES States
should use comparable means.
NPDES authorities should set
priorities for enforcement based on
environmental impacts or sensitive
areas affected by CSOs. Permittees that
have voluntarily initiated monitoring
and are progressing expeditiously
toward appropriate CSO controls should
be given due consideration far their
efforts.
1. Enforcement for Compliance With
Phase I Permits
Enforcement for compliance with
Phase 1 permits will focus on
requirements to implement at least the
nine minimum controls, and develop
the long-term CSO control plan leading
to compliance with the requirements of
the CWA. Where immediate compliance
with the Phase I permit is infeasible, the
NPDES authority should issue an
enforceable schedule, in concert with
the Phase I permit, requiring
compliance with the CWA and
imposing compliance schedules with
dates for each of the nine minimum
controls as soon as practicable. All
enforcement authorities should require
compliance with the nine minimum
controls no later than January 1,1997.
Where the NPDES authority is issuing
an order with a compliance schedule for
the nine minimum controls, this order
should also include a schedule for
development of the long-term CSO
control plan.
If a CSO permittee fails to meet the
final compliance date of the schedule,
the NPDES authority should initiate
appropriate judicial action.
2. Enforcement for Compliance With
Phase II Permits
The main focus for enforcing
compliance with Phase II permits will
be to incorporate the long-term CSO
control plan through a civil judicial
action, an administrative order, or other
enforceable mechanism requiring
compliance with the CWA and
imposing a compliance schedule with
appropriate milestone dates necessary to
implement the plan.
In general, a judicial order is the
appropriate mechanism for
incorporating the above provisions for
Phase II. Administrative orders.
however, may be appropriate for
permittees whose long-term control
plans will take less tban Pvc years to
complete, and for minors that have
complied with the final date of the
enforceable order for compliance with
their Phase 1 permit. If necessary, any of
the nine minimum controls that have
not been implemented by this time
should be included in the terms of the
judicial order.
D. Penalties
EPA is prepared not to seek civil
penalties for past CSO violations, if
permittees have no discharges during
dry weather and meet the objectives and
schedules of this Policy.
Notwithstanding this, where a permittee
has other significant CWA violations for
which EPA or the State is taking judicial
action, penalties may be considered as
part of that action for the following:
1. CSOs during dry weather;
2. Violations of CSO-related
requirements in NPDES permits;
consent decrees or court orders which
predate this policy: or
3. Other CWA violations.
EPA will not seek penalties for past
CSO violations from permittees that
fully comply with the Phase I permit or
enforceable order requiring compliance
with the Phase ! permit. For permittees
that fail to comply, EPA will exercise its
enforcement discretion in determining
whether to seek penalties for the time
period for which the compliance
schedule was violated. If the milestone
dates of the enforceable schedule are not
achieved and penalties are sought.
penalties should be calculated from the
last milestone date that was met.
At the time of the judicial settlement
imposing a compliance schedule
implementing the Phase [I permit
requirements, EPA will not seek
penalties for past CSO violations from
permittees that fully comply with the
enforceable order requiring compliance
with the Phase I permit and if the terms
of the judicial order are expediliously
agreed to on consent. However,
stipulated penalties for violation of the
judicial order generally should be
included in the order, consistent with
existing Agency policies. Additional
guidance on stipulated penalties
concerning long-term CSO controls and
attainment of WQS will be issued.
Paperwork Reduclion Act
The information collection
requirements in this policy have been
approved by the Office of Management
and Budget (OMB) under the Paperwork
Reduction Act. 44 U.S.C. 3501 et seq
and have been assigned OMB control
number 2040-0170.
This collection of information has an
estimated reporting burden averaging
578 hours per response and an
estimated annual recordkeeping burden
averaging 25 hours per recordkeeper.
These estimates include time for
reviewing instructions, searching
existing data sources, gathering and
maintaining the data needed, and
completing and reviewing the collection
of information.
Send comments regarding the burden
estimate or any other aspect of this
collection of information, including
suggestions for reducing this burden to
Chief, Information Policy Branch: EPA:
401 M Street SW. (Mail Code 2136):
Washington. DC 20460: and to the
Office of Information and Regulatory
Affairs, Office of Management and
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Appendix A
18698 Federal Register / Vol. 59. No. 75 / Tuesday. April 19. 1994 / Notices
Budget. Washington. DC 20503. marked
"Attention: Desk Officer for EPA."
|FR Doc. 94-9295 Filed 4-1S-94; 8:45 am)
BMJJtQ COOC «i«0 II f
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Report to Congress on the Impacts and Control of CSOs and SSOs
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Appendix A
A.3 Memorandum: Addition of Chapter X to Enforcement Management System
March 7, 1996
MEMORANDUM
SUBJECT: Addition of Chapter X to Enforcement Management
System (EMS): Setting Priorities for Addressing
Discharges from Separate Sanitary Sewers
FROM: Steven A. Herman [SIGNED]
Assistant Administrator
TO: Water Management Division Directors, Regions I-X
NPDES State Enforcement Directors
Regional Counsels, Regions I-X
I am pleased to transmit to you a new chapter in final form
for the Enforcement Management System (EMS) Guide. This new chapter
provides a method of setting priorities for addressing discharges
of untreated sewage from separate sanitary sewer collection systems
prior to the headworks of a sewage treatment plant. Included with
this chapter is an Enforcement Response Guide, specifically tailored
to these types of discharges.
I want to express my appreciation to those Regional,
Headquarters, State personnel, and the members of the Federal
Advisory Sub-Committee for Sanitary Sewer Overflows (SSO) who helped
develop this document. The Advisory Sub-Committee reviewed it at
two public meetings in August and October, 1995. The cooperation
and hard work of all interested parties has produced this final
document which I believe will help protect public health and the
environment from these serious sources of water pollution.
This guidance supplements the current EMS by establishing
a series of guiding principles and priorities for use by EPA
Regions and NPDES States in responding to separate sanitary sewer
discharge violations. The guidance allows sufficient flexibility
to alter these priorities based on the degree of public health
or environmental risk presented by specific discharge conditions.
Implementation of this guidance by EPA and the States will promote
national consistency in addressing discharges from separate sanitary
sewers. Implementation will also ensure that
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enforcement resources are used in ways that maximize public health
and environmental benefits.
The Regions should ensure that all approved States are aware
of this additional EMS guidance, and the Regions and NPDES States
should begin the process of modifying their written EMS documents
to include it. Both Regions and States should have these documents
revised and implemented no later that November 15, 1996.
If you have questions about this document, please feel free to
contact Brian J. Maas, Director, Water Enforcement Division (202/
564-2240), or Kevin Bell of his staff (202/564-4027).
cc: Mike Cook, OWM
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Appendix A
A.4 Enforcement Management System - Chapter X
THE ENFORCEMENT MANAGEMENT SYSTEM
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
(CLEAN WATER ACT)
CHAPTER X: Setting Priorities for Addressing Discharges
from Separate Sanitary Sewers
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF REGULATORY ENFORCEMENT
1996
ENFORCEMENT MANAGEMENT SYSTEM - CHAPTER X
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Setting Priorities for Addressing Discharges from
Separate Sanitary Sewers
Discharges of raw or diluted sewage from separate sanitary
sewers before treatment can cause significant public health and
environmental problems. The exposure of the public to these
discharges and the potential health and environmental impacts are
the primary reasons EPA is developing this additional guidance on
these discharges. This document provides a method of setting
priorities for regulatory response, and serves as a supplement to
the Enforcement Management System guidance (EMS, revised February
27, 1986). As such, this document addresses only those
discharges which are in violation of the Clean Water Act. As a
general rule, the discharges covered by this guidance constitute
a subset of all discharges from separate sanitary sewer systems.
Legal Status
In the context of this document, a "discharge from a
separate sanitary sewer system" (or "discharge") is defined as
any wastewater (including that combined with rainfall induced
infiltration/inflow) which is discharged from a separate sanitary
sewer that reaches waters of the United States prior to treatment
at a wastewater treatment plant. Some permits have specific
requirements for these discharges, others have specific
prohibitions under most circumstances, and still other permits
are silent on the status of these discharges.
The legal status of any of these discharges is specifically
related to the permit language and the circumstances under which
the discharge occurs. Many permits authorize these discharges
when there are no feasible alternatives, such as when there are
circumstances beyond the control of the municipality (similar to
the concepts in the bypass regulation at 40 CFR Part 122.41 (m)).
Other permits allow these discharges when specific requirements
are met, such as effluent limitations and monitoring/reporting.
Most permits require that any non-compliance including
overflows be reported at the end of each month with the discharge
monitoring report (DMR) submittal. As a minimum, permits
generally require that overflow summaries include the date, time,
duration, location, estimated volume, cause, as well as any
observed environmental impacts, and what actions were taken or
are being taken to address the overflow. Most permits also
require that any non-compliance including overflows which may
endanger health or the environment be reported within 24 hours,
and in writing within five days. Examples of overflows which may
endanger health or the environment include major line breaks,
overflow events which result in fish kills or other significant
harm, and overflow events which occur in environmentally
sensitive areas.
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Appendix A
For a person to be in violation of the Clean Water Act:
1) a person must own, operate, or have substantial control over
the conveyance from which the discharge of pollutants occurs,
2) the discharge must be prohibited by a permit, be a violation
of the permit language, or not be authorized by a permit, and 3)
the discharge must reach waters of the United States. In
addition, discharges that do not reach waters of the United
States may nevertheless be in violation of Clean Water Act permit
requirements, such as those requiring proper operation and
maintenance (O&M) , or may be in violation of state law.
Statement of Principles
The following six principles should be considered as EPA
Regions and States set priorities for addressing violating
discharges from separate sanitary sewers:
1. All discharges (wet weather or dry weather) which cause or
contribute significantly to water quality or public health
problems (such as a discharge to a public drinking water supply)
should be addressed as soon as physically and financially
possible. Other discharges may, if appropriate, be addressed in
the context of watershed/basin plans (in conjunction with state
or federal NPDES authorities).
2. Discharges which occur in high public use or public access
areas and thus expose the public to discharges of raw sewage
(i.e., discharges which occur in residential or business areas,
near or within parks or recreation areas, etc.) should be
addressed as soon as physically and financially possible.
3. Dry weather discharges should be addressed as soon as
physically and financially possible.
4. Discharges due to inadequate operation and routine
maintenance should be addressed as soon as possible. (Physical
and financial considerations should be taken into account only in
cases where overflow remedies are capital intensive.)
5. Discharges which could be addressed through a comprehensive
preventive maintenance program or with minor capital investment
should be addressed as soon as physically and financially
possible.
6. With respect to principles 1 through 5 above, schedules of
compliance which require significant capital investments should
take into account the financial capabilities of the specific
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Report to Congress on the Impacts and Control ofCSOs and SSOs
municipality, as well as any procedures required by state and
local law for publicly owned facilities in planning, design, bid,
award, and construction. (See later sections on Schedules).
Causes of Sanitary Sewer Discharges
Discharges from separate sanitary sewers can be caused by a
variety of factors including, but not limited to:
1. Inadequate O&M of the collection system. For example,
failure to routinely clean out pipes, failure to properly seal or
maintain manholes, failure to have regular maintenance of
deteriorating sewer lines, failure to remedy poor construction,
failure to design and implement a long term replacement or
rehabilitation program for an aging system, failure to deal
expeditiously with line blockages, or failure to maintain pump
stations (including back-up power).
2. Inadequate capacity of the sewer system so that systems
which experience increases in flow during storm events are unable
to convey the sewage to the wastewater treatment plant. For
example, allowing new development without modeling to determine
the impact on downstream pipe capacity, insufficient allowance
for extraneous flows in initial pipe design (e.g. unapproved
connection of area drains, roof leaders, foundation drains), or
overly optimistic Infiltration/Inflow reduction calculations.
3. Insufficient capacity at the wastewater treatment plant so
that discharges from the collection system must occur on a
regular basis to limit flows to the treatment plant. For
example, basic plant designs which do not allow sufficient design
capacity for storm flows.
4. Vandalism and/or facility or pipeline failures which occur
independent of adequate O&M practices.
Applicable Guidance
For many years, EPA and the States have been working with
municipalities to prevent discharges from separate sanitary sewer
systems. The preferred method has been to use the general policy
on responding to all violations of the Clean Water Act which is
contained in the EMS guidance. Factors which are considered are
the frequency, magnitude, and duration of the violations, the
environmental/public health impacts, and the culpability of the
violator. This guidance sets up a series of guiding principles
for responding to separate sanitary sewer discharge violations,
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Appendix A
and it supplements the current EMS.
Every EPA Region and State uses some form of this general
enforcement response guidance as appropriate to the individual
state processes and authorities. Under the guidance, various EPA
Regions and States have taken a large number of formal
enforcement actions over the past several years to address
sanitary sewer discharge problems across the country. Responses
have included administrative orders and/or civil judicial actions
against larger municipalities to address sanitary sewer discharge
problems, resulting in substantial injunctive relief in some
cases.
As a result of EPA Region and State enforcement efforts, a
number of municipalities have invested substantial resources in
diagnostic evaluations and designing, staffing, and implementing
O&M plans. Other municipalities have undertaken major
rehabilitation efforts and/or new construction to prevent
sanitary sewer discharges.
Priorities for Response
There are approximately 18,500 municipal separate sanitary
sewage collection systems (serving a population of 135 million),
all of which can, under certain circumstances, experience
discharges. Given this fact, the Agency has developed a list of
priorities in dealing with the broad spectrum of separate
sanitary sewer discharges to ensure that the finite enforcement
resources of EPA and the States are used in ways that result in
maximum environmental and public health benefit. However, these
priorities should be altered in a specific situation by the
degree of health or environmental risks presented by the
condition(s).
In the absence of site-specific information, all separate
sanitary sewer discharges should be considered high risk because
such discharges of raw sewage may present a serious public health
and/or environmental threat. Accordingly, first priority should
be given within categories (such as dry weather discharges and
wet weather discharges) to those discharges which can be most
quickly addressed. The priority scheme listed below takes this
into account by first ensuring that municipalities are taking all
necessary steps to properly operate and maintain their sewerage
systems. Corrective action for basic O&M is typically
accomplished in a short time, and can yield significant public
health and environmental results.
Risk again becomes a determinant factor when conditions
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Report to Congress on the Impacts and Control ofCSOs and SSOs
warrant long term corrective action. The goal here should be to
ensure that capital intensive, lengthy compliance projects are
prioritized to derive maximum health and environmental gains.
The priorities for correcting separate sanitary sewer
discharges are typically as follows:
1) Dry weather, O&M related: examples include lift stations or
pumps that are not coordinated, a treatment plant
that is not adjusted according to the influent flow, poor
communication between field crews and management,
infiltration/inflow, and/or pretreatment problems.
2) Dry weather, preventive maintenance related: examples include
pumps that fail due to poor maintenance, improperly calibrated
flow meters and remote monitoring equipment, insufficient
maintenance staff, deteriorated pipes, and/or sewers that are not
cleaned regularly.
3) Dry weather, capacity related: examples include an
insufficient number or undersized pumps or lift stations,
undersized pipes, and/or insufficient plant capacity.
4) Wet weather, O&M related: examples include excessive inflow
and/or infiltration (such as from improperly sealed manhole
covers), inadequate pretreatment program (i.e. excessive
industrial connections without regard to line capacity),
uncoordinated pump operations, treatment plant operation that is
not adjusted according to the influent flow, poor coordination
between field crews and management, illegal connections, and/or
no coordination between weather forecast authorities and sewer
system management.
5) Wet weather, preventive maintenance related: examples
include poor pump maintenance leading to failure, improperly
calibrated flow meters and remote monitoring equipment,
insufficient maintenance staff, and/or sewers that are not
cleaned regularly.
6) Wet weather, O&M minor capital improvement related: examples
include the upgrading of monitoring equipment, pumps, or computer
programs, and/or repair or replacement of broken manholes or
collapsed pipes.
7) Wet weather capacity, quick solution related: examples
include a known collection system segment that is a "bottleneck",
pumps beyond repair in need of replacement, and/or need for
additional crews or technical staff.
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Appendix A
7
8) Wet weather, capacity, health impact related requiring long
term corrective action: examples include frequent discharges to
public recreational areas, shellfish beds, and/or poor
pretreatment where the total flow is large.
9) Wet weather, capacity, sensitive area related requiring long
term corrective action: examples include discharges to
ecologically and environmentally sensitive areas, as defined by
State or Federal government.
Selecting A Response
The appropriate regulatory response and permittee response
for separate sanitary sewer discharges will depend on the
specifics of each case. The regulatory response can be informal,
formal, or some combination thereof. Typical regulatory
responses include a phone call, Letter of Violation (LOV),
Section 308 Information Request, Administrative Order (AO),
Administrative Penalty Order (APO), and/or judicial action. The
permittee response can range from providing any required
information to low cost, non-capital or low capital improvements
to more capital intensive discharge control plans.
The attached chart lists some categories of separate
sanitary sewer noncompliance along with the range of response for
each instance. The chart is intended as a guide. The responses
listed on the chart are not to be considered mandatory responses
in any given situation. EPA and the States should use the full
range of regulatory response options (informal, formal, or some
combination thereof) to ensure that the appropriate response or
remedy is undertaken by the permittee or municipality. All
regulatory responses should be in accordance with the concept of
the EMS regarding orderly escalation of enforcement action.
Developing Compliance Schedules
A compliance schedule should allow adequate time for all
phases of a sanitary sewer discharge control program, including
development of an O&M plan, diagnostic evaluation of the
collector system, construction, and enhanced O&M.
Municipalities should be given a reasonable length of time to
develop schedules so they can realistically assess their
compliance needs, examine their financing alternatives, and work
out reasonable schedules for achieving compliance. Nevertheless,
timelines for schedules should be as short as physically and
financially possible.
Short Term Schedules
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In general, short term schedules would be appropriate for
sanitary sewer discharges involving O&M problems, or where only
minor capital expenses are needed to correct the problem. The
schedule should have interim dates and a final compliance date
incorporated in the administrative order or enforcement
mechanism.
Comprehensive Discharge Control Schedules
Comprehensive discharge control schedules should be used
where specific measures must be taken to correct the discharges,
and the measures are complicated, costly, or require a
significant period of time to implement. If appropriate, these
schedules should include the use of temporary measures to address
high impact problems, especially where a long term project is
required to correct the sanitary sewer discharge violation.
When working with municipalities to develop comprehensive
schedules, EPA Regions and States should be sensitive to their
special problems and needs, including consideration of a
municipality's financial picture. Factors that should be
considered are the municipality's current bond rating, the amount
of outstanding indebtedness, population and income information,
grant eligibility and past grant experience, the presence or
absence of user charges, and whether increased user charges would
be an effective fund-raising mechanism, and a comparison of user
charges with other municipalities of similar size and population.
Physical capability should be considered when schedules are
developed. Schedules should include interim milestones and
intermediate relief based on sound construction techniques and
scheduling such as critical path method. Compliance schedules
should be based on current sewer system physical inspection data
adequate to design sanitary sewer discharge control facilities.
Schedules should not normally require extraordinary measures such
as overtime, short bidding times, or other accelerated building
techniques. Where possible, schedule development should be
completed according to normal municipal government contracting
requirements.
Financial capability should also be considered in schedule
development, including fiscally sound municipal financing
techniques such as issuing revenue bonds, staging bond issuance,
sequencing project starts, sensitivity to rate increase
percentages over time.
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Appendix A
Note: The intent of this guidance is to aid the Regions and
States in setting priorities for enforcement actions based on
limited resources and the need to provide a consistent level of
response to violations. This does not represent final Agency
action, but is intended solely as guidance. This guidance is not
intended for use in pleading, or at hearing or trial. It does
not create any rights, duties, obligations, or defenses, implied
or otherwise, in any third parties. This guidance supplements
the Agency's Enforcement Management System Guide (revised
February 27, 1986).
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Report to Congress on the Impacts and Control ofCSOs and SSOs
ENFORCEMENT RESPONSE GUIDE
DISCHARGES FROM SEPARATE SANITARY SEWERS
NONCOMPLIANCE
Discharge without a
permit or in violation
of general prohibition
Discharge without a permit
or in violation of general
prohibition
Discharge without a permit
or in violation of general
prohibition
Discharge without a permit
or in violation of general
prohibition
Discharge without a permit
or in violation of general
prohibition
Discharge without a permit
or in violation of general
prohibition
Discharge without a permit
or in violation of general
prohibition
Discharge without a permit
or in violation of general
prohibition
Discharge without a permit
or in violation of general
prohibition
Discharge without a permit
or in violation of general
prohibition
CIRCUMSTANCES
Isolated & infrequent,
dry weather O&M
related
Isolated & infrequent,
dry weather capacity
related
Isolated & infrequent,
wet weather O&M
related
Isolated & infrequent,
wet weather, quick and
easy solution
Isolated & infrequent, wet
weather capacity related,
health and/or sensitive areas
Isolated & infrequent, wet
weather capacity related,
non-health, non-sensitive areas
Cause unknown
Permittee does not respond
to letters, does not follow
through on verbal or written
agreement
Frequent, does not signifi-
cantly affect water quality,
no potential public health
impact
Frequent, cause or contribute
significantly to WQ problems,
or occur in high public use and
public access areas, or other-
wise affect public health
RANGE OF RESPONSE
Phone call, LOV,
308 request
308 request, AO,
APO, Judicial action
Phone call, LOV,
308 request
LOV, 308 request
LOV, 308 request, AO,
APO
Phone call, LOV, 308
request
Phone call, LOV, 308
request
AO, APO, judicial
action
LOV, 308 request,
AO, APO
AO, APO, judicial
action
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Appendix A
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ENFORCEMENT RESPONSE GUIDE
DISCHARGES FROM SEPARATE SANITARY SEWERS
NONCOMPLIANCE
CIRCUMSTANCES
RANGE OF RESPONSE
Missed interim date in CDCP
Will not cause late final date
or other interim dates
LOV
Missed interim date in CDCP
Missed final date in CDCP
Missed final date in CDCP
Failure to report overflows
(as specified in permit)
Failure to report overflows
(as specified in permit)
Failure to report overflows
(as specified in permit)
Failure to report permit
requirements
Will result in other missed
dates, no good and valid cause
Violation due to force
majeure
Failure or refusal to comply
without good and valid
cause
Isolated and infrequent,
health related
Isolated and infrequent, water
quality and environment related
Permittee does not respond to
letters, does not follow through
on verbal or written agreement,
or frequent violation
Any instance
LOV, AO, APO,
judicial action
Contact permittee and
require documentation of
good or valid cause
AO, APO or judicial
action
Phone call, LOV, AO, APO
Phone call, LOV, AO, APO
AO, APO, judicial action,
request for criminal
investigation
Phone, LOV, AO, APO
CDCP=Comprehensive Discharge Control Plan
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Appendix B
Human Health Expert and Stakeholder
Meeting Summaries
B.1 Summary of the August 14-15,2002,
Experts Workshop on Public
Health Impacts of Sewer Overflows
(Abstract and Background)
B.2 Stakeholder Meeting Summary,
Washington, D.C.
B.3 Stakeholder Meeting Summary,
Huntington Beach,CA
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Appendix B
B.1 Summary of the August 14-15, 2002, Experts Workshop on Public Health Impacts of Sewer Overflows (Abstract
and Background)
United States Off ice of Wastewater Management EPA 833-R-02-002
Environmental Protection Washington, D.C. 20460 November 2002
Agency www.epa.gov/npdes
Summary of the August 14- 15, 2002,
Experts Workshop on Public Health
Impacts of Sewer Overflows
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Summary of the August 14 - 15, 2002, Experts Workshop on Public
Health Impacts of Sewer Overflows
Table of Contents
Abstract 1
Background 1
Rationale for the Workshop 1
Opening Remarks 3
Review of Goals and Agenda 3
Overview of the 2001 and 2003 Reports to Congress 5
The Public Health Chapter of the 2003 CSO/SSO Report to Congress:
Questions and Proposed Methods 8
Discussion Session 1: Characterizing Pathogens and Pollutants 13
Discussion Session 2: Pathways of Exposure 22
Discussion Session 3: Open Discussion Session 25
Welcome and Structure of Day Two 26
Breakout Session A: Significance of the CSO and SSO Problem 26
Breakout Session B: Options for the Current Study 28
General Discussion 30
Final Comments and Next Steps 31
Appendices
Appendix A: Attendee List
Appendix B: Agenda
Appendix C: Clarifying Questions from Observers
Appendix D: The Public Involvement Process for the 2001 and 2003 Reports to Congress
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Appendix B
Abstract
In embarking upon the task of assessing the human health impact portion of Congress' request for
a report on the impacts and control of sewer overflows in the United States, initial research
revealed that relatively little data were available that linked waterborne illness or other exposures
to combined sewer overflows (CSOs) and sanitary sewer overflows (SSOs). In response to these
challenges, EPA held a Public Health Impacts Experts Workshop on August 14 and 15, 2002. A
group of nine external and EPA experts in public health, epidemiology, and wastewater treatment
attended the workshop. Observers included representatives of stakeholder groups and EPA
personnel. This workshop did not constitute an advisory committee under the Federal Advisory
Committees Act (FACA), but rather solicited individual opinions and provided a forum for
information exchange related to this Report to Congress.
Background
In the Consolidated Appropriations Act for fiscal year 2001, also known as the "Wet Weather
Water Quality Act of 2000"or "2000 Amendments to the Clean Water Act" (CWA), Congress
made several changes to the CWA regarding combined sewer overflows (CSOs) (P.L. 106-554).
Among these changes was a requirement for the U.S. Environmental Protection Agency (EPA) to
provide two Reports to Congress. The first report, Implementation and Enforcement of the
Combined Sewer Overflow Control Policy (EPA 833-R-01-003), was delivered on January 29,
2002. The second report, which is due to Congress on December 15, 2003, is to investigate:
• The extent of the human health and environmental impacts caused by municipal
CSOs and sanitary sewer overflows (SSOs), including the location of discharges
causing such impacts, the volume of pollutants discharged, and the constituents
discharged;
The resources spent by municipalities to address these impacts; and
• An evaluation of the technologies used by municipalities to address these impacts.
Rationale for the Public Health Experts Workshop
In embarking upon the task of assessing the human health impact portion of Congress' request,
initial research revealed that relatively little data were available that linked waterborne illness or
other exposures to CSOs and SSOs. Factors complicating collection of information and data in
this arena include public perception of reporting overflows in recreational areas; difficulty in
contributing CSO/SSO loadings of pathogens in our nation's waters from other background
sources; multiple possible pathways for fecal-related illness; underreporting of certain types of
waterborne illnesses; and a lack of comprehensive local or national tracking for such illnesses.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
In response to these challenges, EPA held a Public Health Impacts Experts Workshop on August
14 and 15, 2002. The purpose of this workshop was to enlist technical and subject matter experts
from federal agencies, local health departments, and academia to ensure that EPA frames the
study questions correctly, benefits from all pertinent data, and develops a methodology that bears
out actual experiences. A group of recognized experts in the field of public health and interested
observers met with the goals and objectives of:
• Fully elucidating the issues and the magnitude of those issues associated with
health impacts of CSOs and SSOs;
• Reviewing and supplementing data and information sources identified to date; and
Critiquing the proposed methodology for gathering and analyzing the public health
information and data for the 2003 report.
The experts were asked to give individual opinions relating to the study questions. No consensus
opinions or policy recommendations were solicited.
This Public Health Experts workshop is part of a larger public involvement process for the 2001
and 2003 CSO/SSO Reports to Congress. It occurs between two broader stakeholders' meetings
(June 2001 and summer 2003, anticipated), at which a broad range of stakeholders discuss and
provide input on draft report findings and recommendations, experiences in CSO control, and
future policy and program directions. For a more detailed discussion of the overall stakeholder
approach, please refer to Appendix D of this summary.
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Appendix B
B.2 Stakeholder Meeting Summary, Washington, D.C.
2003 Report to Congress on the Impacts and Control of Combined Sewer
Overflows and Sanitary Sewer Overflows
Stakeholder Meeting Summary
Washington, D.C.
On June 23 and 24, 2003, the U.S. Environmental Protection Agency held a meeting in Washington,
D.C., to discuss the upcoming Report to Congress on the impacts and control of CSOs and SSOs. The
meeting held at the Renaissance Hotel, 999 9th St. NW, provided an opportunity for EPA to present the
results of the data collection, request verification of information and data sources, and solicit feedback on
preliminary findings and interpretation.
The main goals of the meeting were to:
• Discuss the data, report methodology, and analysis of the 2003 Report to Congress;
• Discuss implications of the major analyses in the report; and
• Discuss participants' experiences in controlling impacts from CSOs and SSOs.
The summary below describes the presentations given to outline the contents of the report and recounts
the resulting discussions. The summary is organized into the following major sections, which correspond
to the meeting agenda:
Opening Remarks
Background on the Report
Characterization of CSOs and SSOs
Environmental Impacts of CSOs and SSOs
Closing Remarks, Day One
Recap of Day One and Agenda Review for Day Two
Welcome and Opening Remarks, Day Two
Human Health Impacts of CSOs and SSOs
Technologies for CSO and SSO Control
Resources Spent Addressing CSOs and SSOs
Common Themes Heard During the Meeting
Closing Remarks, Day Two
Opening Remarks
James A. Hanlon - Director, Office of Wastewater Management, EPA
Mr. Hanlon opened the meeting by welcoming the participants to Washington, D.C., and providing
an overview of the 2000 Wet Weather Water Quality Act, the 2001 CSO Report to Congress, and its
associated stakeholder meeting. Mr. Hanlon reminded the participants that this Report was not intended
to set policy, instead it was intended to present data and cite additional data sources that Congress
could look to when entering into policy discussions. He mentioned that responding to the charge from
Congress had proven difficult, specifically in identifying loadings and in correlating discharges with
environmental and human health impacts.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Background on the 2003 Report to Congress
Kevin DeBell - Office of Wastewater Management, EPA
Mr. DeBell presented the background to the 2003 Report to Congress. He started by mentioning
the near-term EPA policies that directly led to the request for the 2003 Report to Congress. First, he
described the 1994 National CSO Control Policy which formalized EPA's management expectations for
CSS communities. Next, a summary of the 2001 Report to Congress - Implementation and Enforcement of
the Combined Sewer Overflow Control Policy was presented. This report acted as a program evaluation in
which success of CSO Control Policy implementation was assessed; one useful product of the 2001 Report
is the CSO database, which includes information on all CSO permits. Mr. DeBell then mentioned the
draft SSO Notice of Proposed Rulemaking, and the 2000 Wet Weather Water Quality Act, which required
the 2003 Report. The statutory requirements for the 2003 Report are stated below:
The Administrator of the Environmental Protection Agency shall transmit to Congress a report
summarizing:
a. the extent of human health and environmental impacts caused by municipal combined
sewer overflows and sanitary sewer overflows, including the location of discharges causing
such impacts, the volume of pollutants discharged, and the constituents discharged;
b. resources spent by municipalities to address these impacts; and
c. an evaluation of the technologies used by municipalities to address these impacts.
Mr. DeBell next explained that EPA is not required to have a public review of Reports to Congress, but
that this particular program has a legacy of stakeholder collaboration, which EPA values.
Finally, Mr. DeBell presented the report outline. The report is organized as follows:
Introduction
Background
Methodology
Characteristics of CSOs and SSOs
Environmental Impacts of CSOs and SSOs
Human Health Impacts of CSOs and SSOs
Federal and State Actions to Control CSOs and SSOs
Technologies Used to Reduce the Impacts of CSOs and SSOs
Findings and Recommendations
Stakeholder Questions and Comments on the Background Presentation
Questions and comments received after the background presentation are summarized below. The
comments represent stakeholder opinion(s) and may not reflect EPA's position.
• Are data collected during the Report to Congress effort also being used to inform the SSO economic
analysis?
• Is EPA still attempting to make an economic model to justify the SSO Rule, despite the fact that the
public health experts (during the August 2002 Experts Workshop) said that an economic model was
not feasible?
• In relation to municipalities' actions on CSOs and SSOs, will the Report to Congress help
municipalities prioritize resources spent on CSO/SSO versus other wet weather events?
• Regarding the Pretreatment Rule streamlining, enforcement of this rule may reduce the human health
risks associated with CSOs and SSOs fed by industrial wastewater flows during wet weather. Has EPA
consulted with municipalities regarding enforcement of this rule?
• Will the SSO/CSO data (compiled for both Reports to Congress) be publicly available? When?
• Some stakeholders were worried about the lack of representation at the stakeholder meeting from
certain stakeholder groups (i.e., NOAA and public health officials) and urged EPA to try to increase
representation from each group.
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• A stakeholder pointed out that many enforcement actions and consent decrees are currently in place
(for CSO and SSO violations), and wanted to ensure that these actions were represented in the report.
Characterization of CSOs and SSOs
Kevin DeBell - Office of Wastewater Management, EPA
Mr. DeBell presented data on the location of CSO and SSO discharges, the volume of pollutants
discharged, the constituents discharged, and the frequency of discharge events.
This presentation defined a CSO as a mixture of untreated sewage and storm water discharged from a
combined sewer system at a point prior to the headworks of the POTW. Generally, CSOs occur during
wet weather when the CSS becomes overloaded. SSO is defined as a discharge of untreated or partially
treated wastewater from a sanitary sewer system at any point prior to the headworks of a POTW. Backups
of wastewater to private property are not included in the definition of SSO used for this Report to
Congress.
Data Sources for the Characterization Chapter
EPA used the following data sources to characterize CSOs and SSOs.
State databases for tracking CSO and SSO events;
NPDES permit files;
Approximately 80 interviews with state and municipal officials;
LTCPs and other capital improvement documentation;
Literature review; and
Existing EPA documentation, including technical reports and products of cooperative
agreements.
Key Research Questions for the Characterization Chapter
This presentation introduced three key research questions for the characterization chapter:
• How many NPDES permits exist for combined sewer systems and sanitary sewer systems?
• What are the common pollutants found in CSOs and SSOs?
• What are the volume, frequency, and location of CSOs and SSOs?
Stakeholder Questions and Comments for the Characterization Chapter
Questions and comments received after the characterization presentation are summarized below. The
comments represent stakeholder opinion(s) and may not reflect EPA's position.
• With respect to the pollutants and pathogens found in CSOs and SSOs, specifically concentrations,
stakeholders questioned the accuracy of the data presented in the meeting and asked that it be
verified. Stakeholders identified possible data sources, including the Nationwide Urban Runoff
Program and Hydraulic Characteristic Reports (needed for NPDES permits).
• The concentrations of constituents within CSOs, SSOs, and storm water vary widely, depending
on many factors, such as the amount of precipitation or sources contributing to the wastewater.
Therefore, it is very difficult to present general characteristics. Stakeholders questioned whether CSOs
and SSOs should be characterized in this fashion. Some suggested concentrating on specific and acute
impacts.
• Stakeholders suggested that EPA take a look at "hot spots" or incidents of the most dangerous,
concentrated CSOs and SSOs.
• Stakeholders suggested that EPA express to Congress what can be supported by available data- local,
acute impacts can be terrible, while the national impact looks relatively small; both are very difficult
to track or assess.
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• Stakeholders said the information presented in this section needed to be placed in the context of the
environmental and human health impacts.
• Do not present data in aggregate format. For example, separate wet weather and dry weather SSO
data.
• Characteristics of the receiving water need to be addressed.
• More specificity is needed. Add community data where available, including volume, cause, and
receiving water information. A stakeholder thought that this would help Congress better understand
why national data are and are not representative.
• Stakeholders asked for clarification of the charge from Congress. Was the directive to look at
municipalities only or also at decentralized wastewater treatment systems?
• Stakeholders were concerned that describing the volume of current CSO discharges as "a large
amount" would give Congress the impression that municipalities were not doing anything to correct
the CSO problem.
• Were small communities contacted and interviewed in this methodology?
• A clarifying question was asked regarding the statistic on the amount of SSOs that reach waterbodies
and how researchers were estimating the impact on sensitive areas.
• Concerns were raised about how information presented in this report was going to inform Congress's
decisions regarding wet weather policy as a whole.
Environmental Impacts of CSOs and SSOs
Julia Moore - Limno-Tech, Inc.
Ms. Moore began by defining "environmental impacts" as water quality, aquatic life, and aesthetic
impacts that affect designated uses. Violations of water quality standards were used as an indicator
for environmental impacts. While researching this chapter, EPA used previously completed national,
state, and local assessments. Literature and web searches were performed and interviews with state and
municipal officials were carried out.
EPA sought to characterize types of environmental impacts from CSOs and SSOs. First, EPA presented
ranges in concentrations of the constituents typically found in CSOs and SSOs. EPA presented the results
of assessments of environmental impacts caused by CSOs and SSOs. EPA acknowledged that while beach
closures and shellfish bed closures have been traced to CSOs and SSOs, the data are not complete.
EPA described planned national assessments in which CSO outfall locations will be integrated with EPAs
WATERS database. This will allow CSO locations to be associated with information such as 303(d)
impaired reaches and drinking water intakes.
Conclusions for the Environmental Impacts Chapter
EPA presented preliminary conclusions regarding the environmental impacts from CSOs and SSOs.
These included:
• CSOs and SSOs contain pollutants that cause impairments to designated uses, as reported in
national assessments.
• CSOs and SSOs can be a principal cause or a contributing cause of an environmental impact.
• National data are inconsistent in tracking CSOs and SSOs as a direct cause of impairment.
• While data are not comprehensive, some national estimates of use impairment have been
made.
• State and local examples of cause and effect exist where CSO and SSO reporting and tracking
are undertaken.
EPA asked the stakeholders present at the meeting for additional information on documented
environmental impacts from CSOs and SSOs.
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Appendix B
Stakeholder Questions and Comments on the Environmental Impacts Chapter
Questions and comments received after the environmental impacts presentation are summarized below.
The comments represent stakeholder opinion(s) and may not reflect EPA's position.
• Need to put a greater emphasis on water quality impacts.
• Need to do a better job of conveying that the data are all anecdotal.
• Researchers have only presented suspicion of impacts.
• Regarding the concentrations of metals in CSOs, some stakeholders commented that most metal
contamination comes from storm water and that CSO controls would not make a difference.
• In the presentation, it was stated that dry weather SSOs were responsible for 7 percent of the total
volume discharged annually. Stakeholders were interested in the characteristics of the other 93
percent of the SSO events contributing to the volume to determine if dry weather overflows are a
problem.
• Some stakeholders expressed the opinion that in urban watersheds, current water quality standards
are impossible to meet during wet weather and that even without CSO or SSO discharges,
waterbodies would exceed water quality standards.
• Stakeholders questioned the source of pathogen data. They stated that municipalities would argue
strongly against the source allocation and mentioned the new Santa Ana Regional Water Quality
Control Board beach closure study in California, which attributed most beach closures to urban
runoff. The stakeholders also mentioned the Four Mile Run TMDL study, in Virginia, in order
to clarify pathogen source information. As a follow up to this comment, it was mentioned that
stormwater may be impacted by cross-connections or SSOs.
• Stakeholders reiterated the need to characterize both dry and wet weather SSOs and CSOs, specifically
stating that the sources of pathogens vary widely depending on whether the event takes place during
dry weather or wet weather.
• A stakeholder commenting on the North Carolina example stated that none of the overflows
highlighted in the presentation appeared to be attributed to wet weather.
• Stakeholders questioned the concentration of metals being contributed to receiving waters via CSOs.
• Regarding shellfish advisories, stakeholders commented that over 90 percent of these were due to
stormwater, not CSOs.
• Stakeholders challenged the research team to find fish kills that occurred during wet weather as a
result of CSOs or SSOs. They doubted this had happened.
• Regarding the Ohio River study, stakeholders commented that urban runoff contributes more
pollutants and pathogens than the CSOs, so removal of CSOs will not show different results.
• Stakeholders stated that many pathogen source studies performed to date showed that primary
sources of pathogens were not of human origin (specifically mentioned studies in Chicago, Detroit,
and Milwaukee). Other stakeholders disagreed, citing Lake Michigan studies.
• Stakeholders pointed out that constituents in CSOs and SSOs can vary. One stakeholder was
particularly concerned about hospital sewage and radionuclide contamination.
• One stakeholder mentioned that it is still very difficult to attribute pathogens to their source. The
stakeholder said that source tracking is still in the research stage and suggested that the technology be
used to monitor CSOs and SSOs. The stakeholder did not agree that current data "show no human
impact" and mentioned that some studies have shown higher human viral concentrations at overflow
sites.
• From a local perspective, stakeholders mentioned that there are other wet weather sources about
which Congress needs to know in order to prioritize funding. Stakeholders wanted to know if this
report would help Congress do that.
• Stakeholders wanted to know what studies were chosen and why.
• Can we make gross estimates about how often CSOs or SSOs will push waterbodies into non-
attainment?
• Regarding the amount of Great Lakes shoreline reported impaired, does EPA know the amount of
shoreline assessed?
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• Regulations currently focus on the most easily regulated communities. There is much disagreement
over how much implementing control regulations will cost. Will the Report to Congress help remedy
this?
Closing Remarks, Day One
Benita Best-Wong - Office of Wastewater Management, EPA
Ms. Best-Wong stated that stakeholder comments would inform the report. She also reminded the
audience that the report was not intended to cover all wet weather events and policy, and therefore, some
of the stakeholder questions were beyond the scope of this report. Ms. Best-Wong then touched on the
Office of Water's watershed management approach, which focuses on many of the other issues raised
during the first day.
Recap of Day One & Agenda Review for Day Two
Linda Manning - Facilitator, SRA International
Ms. Manning described some of the main themes from the previous day, which centered around the
accuracy of data. The themes included:
Do not oversell the data or paint with too broad a brush;
Get a local flavor; it is important to present local impacts;
Fully explain the limitations in the data and be clear about the data gaps;
Do not have interpretational bias;
Be clear about the data gaps and provide the clear message that more data are needed;
Make sure the report is useful by providing context and placing the issues in relation to other
wet weather events;
Acknowledge variability in the data; and
Address big picture policy questions.
Welcome and Opening Remarks, Day Two
Ben Grumbles - Deputy Assistant Administrator for Water, EPA
Mr. Grumbles talked about the importance of the report as well as the importance of the stakeholder
involvement process. He mentioned the challenges confronting the Office or Water in the 21st century
and the resulting shift of EPA's focus from point source controls to a more holistic watershed approach.
Mr. Grumbles touched on the history of the Wet Weather Water Quality Act and Congress's intention for
the Report. He stressed the need for increased monitoring and data gathering to make more informed
policy decisions. Mr. Grumbles addressed the following comments and questions from the stakeholders.
Question/Comment: Progress needs to be made regarding EPA's policy on the blending of treated and
partially untreated wastewater at POTWs during wet weather.
Response: EPA is very much engaged in the blending issue and asked the stakeholders to provide any
information they have on the use of blending to manage wet weather flows.
Question/Comment: Too much government regulation and intervention runs the risk of dictating
technology, which, in turn, may stymie development of innovative alternatives.
Response: The current EPA leadership is very sensitive to the danger of dictating too much and
understands that EPA needs to be open-minded when considering technologies in order to achieve water
quality standards. But, wet weather issues also need to be addressed. We will do our best to be cost
effective and environmentally responsible.
Question/Comment: We currently have decades of data from California, yet will never have enough data.
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Appendix B
Please do not continue to say that we lack enough data. Instead, take our collective knowledge and make
conclusions carefully. Do not skew the data one way or the other.
Question/Comment: At the Expert Workshop, public health officials said that is was not feasible to make
an economic argument for preventing SSOs. What is happening with the EA?
Response: EPA is looking to the report to inform policy decisions.
Human Health Impacts of CSOs and SSOs
Greg Frey - SRA International
Mr. Frey began by introducing the key questions addressed in this chapter:
• What constituents of CSOs and SSOs cause human health impacts?
• Of what consequence are these impacts?
• Which exposure pathways are the most significant and what populations are most sensitive?
• What are the impediments to understanding the linkages between CSOs and SSOs, exposures,
and the human health impacts?
• What is the institutional framework to assess and address potential human health impacts of
CSOs and SSOs?
Mr. Frey explained that EPA first performed an extensive literature review. Then, EPA held an experts
workshop in order to verify the accuracy of data already collected, find new sources, and ascertain an
understanding of experts' opinions of the human health impacts of CSOs and SSOs. EPA next performed
a series of state and community interviews for the purpose of understanding local and state health agency
staff's opinions of the impacts of CSOs and SSOs and to characterize the current activities being carried
out that address this potential threat.
Mr. Frey went on to present the range of human health symptoms resulting from exposure to the
pollutants typically found in CSOs and SSOs. Next, Mr. Frey discussed exposure pathways and the groups
facing the most frequent exposure, as well as the groups most sensitive to waterborne illnesses.
Mr. Frey described the limitations of the major data sources used to identify and describe waterborne
disease outbreaks, one potential indicator of human health impacts from CSOs and SSOs. He next
presented local, site specific examples of outbreaks attributed to exposure to sewage in order to illustrate
the potential for acute health impacts.
Next, EPA outlined the challenges to identifying the human health impacts of CSOs and SSOs. These
include:
• The lack of connectivity in the monitoring and reporting systems for CSO and SSO events,
human exposures, and human health impacts.
The difficulty identifying the source of pathogens.
The difficulty in attributing disease outbreaks to specific CSO and SSO events.
The fact that outbreak reporting to CDC is voluntary.
The understanding that many people who become ill do not seek medical treatment due to
the nature of such illnesses.
There are inconsistent probabilities of diagnoses within the health care system.
The general tendency towards underreporting.
Conclusions for the Human Health Impacts Chapter
Finally, Mr. Frey identified the actions that are currently being taken by state and local governments
to address the human health impacts from CSOs and SSOs and EPA's preliminary conclusions. These
include:
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• The pathogens and pollutants found in CSOs and SSOs have the potential to cause human
health impacts.
• Exposures to the pathogens and pollutants resulting from CSOs and SSOs occur, but are
difficult to quantify.
• Human health impacts from waterborne diseases are underreported.
• Responsibilities for protecting human health from waterborne illnesses are distributed among
many agencies and institutions.
Stakeholder questions and comments on the Human Health Impacts Chapter
Questions and comments received after the human health presentation are summarized below. The
comments represent stakeholder opinion(s) and may not reflect EPA's position.
• Regarding the Austin example, there are no CSOs in Austin, and since there is no source attribution,
the slide on the predictive closings at Barton Springs makes the observer think that all the pathogens
are due to CSOs or SSOs. Be careful which examples you use.
• Does EPA have data on bacterial concentrations in different effluents? If so, add it.
• In the slide that attempts to put the outbreaks of E. coli into perspective, shellfish pathways would be
listed under foodborne, but actually may be exacerbated by an SSO or CSO issue.
• Why did EPA not include shellfish advisories for the Great Lakes?
• Remember to add specific information whenever possible.
• Some stakeholders questioned whether the Brushy Creek, Texas, incident was related to an SSO.
Because it was caused by a power failure, they did not think it was a good example.
• Stakeholders debated how much disease and antibody production could be attributed to SSOs or
CSOs (i.e., how may cases are from human sources).
• Was the Milwaukee outbreak due to a CSO? If so, please clarify.
• There is a Great Lakes Watershed pathogen source study underway, but it will not be completed in
time to inform the Report to Congress.
• Stakeholders questioned the proportion of illness attributable to CSOs or SSOs and thought the
presentation was misleading.
• Rather than stating that quantification of exposure is difficult, EPA should say why it is difficult.
EPA has data about what is "coming out of the pipe" but needs to better understand receiving water
characteristics.
• Regarding the responsibilities slide, there has been a 25-year lag between legislation and the
production of a comprehensive communication system. Will EPA state who should take responsibility
for this?
• Are the pathogen measurements from the sediment or do they just represent the water column
concentrations?
• Why did EPA not include aerosols as a pathway?
• Some stakeholders said that there is no way to attribute a portion of mercury loadings to CSOs and
SSOs.
• Has EPA found characteristics from the different agencies that lead to communication difficulties?
• How do our pathogen concentrations compare to concentrations internationally? Should we
be concerned with migration if pathogen concentration and type is partially dependent on
demographics?
• Make sure that EPA's findings are not biased. Everything presented in the report should be definitely
attributed to CSOs and SSOs.
• How did EPA come up with those populations who are most frequently exposed to pathogens from
CSOs and SSOs? It looks like the majority of illnesses are from drinking water.
What about the risks to people who are exposed to mold after basement backups?
Clarify difference between storm water and sewer overflows.
There is potential to contract the SARS virus from CSOs that are contaminated with hospital waste.
Include all state and community interviews in the Report to Congress, giving specific examples.
There have been thousands of beach water samples that show CSOs are not a problem. Attainment
issues are wet weather problems.
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• Beach closures are based on a 24-hour time lag from the time the sample is collected. There have
been 150-200 closures in Indiana and yet no one has reported sicknesses (despite this time lag);
therefore, the indicators are wrong.
• Need to remove the fish advisories from PCBs and mercury since these constituents are not in CSOs
and SSOs.
• Make a distinction between events occurring during dry weather and wet weather.
• Maybe drinking water monitoring and treatment should be improved, rather than spending on CSO
and SSO controls.
• How would proper enforcement of the long-term surface drinking water rule address
Cryptosporidium issues, especially since so much is attributable to animals?
• Two percent of beach closures are due to CSOs. This may mislead people, since CSOs are
concentrated geographically and therefore the local impacts may be much more significant.
• The report should comment on the relative risks of human versus non-human bacteria.
Technologies for CSO and SSO Control
Kevin DeBell - Office of Wastewater Management, EPA
Mr. DeBell described the key data sources for the technology chapter. These included:
• Extensive literature reviews of existing EPA documentation as well as other sources;
• Interviews with municipal officials;
• Meetings with key EPA staff; and
• Informal peer review by internal and external experts.
Key Questions for the Technologies Chapter
Mr. DeBell introduced the key questions that were addressed:
• What technologies have been used by municipalities to control CSOs and SSOs?
• What factors influence the effectiveness of these technologies?
• Have there been any recent technological innovations in the control of CSOs and SSOs?
While researching this chapter, EPA identified common and promising technologies used by
municipalities to address CSOs and SSOs. From this research, EPA developed technology descriptions
summarizing available technologies and factors influencing their effectiveness. Mr. DeBell explained that
it is very difficult to compare certain types of technologies, as they are designed to deal with different
aspects of wet weather challenges. Therefore, the technologies were not ranked for effectiveness against
each other within this chapter.
Presentation of Technologies
Mr. DeBell said that a wide range of technologies are available and that, within the report, they had been
grouped into five key categories:
Operations and maintenance activities;
Collection system controls;
Storage facilities;
Treatment technologies; and
Low impact development techniques.
Mr. DeBell mentioned that EPA developed case studies on each of the researched technologies, and
presented preliminary findings pertaining to the relative cost of implementing the systems, the type
of system for which the technology was designed, and the pollutants or problems controlled by the
technology.
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Stakeholder Questions and Comments on the Technologies Chapter
Questions and comments received after the technologies presentation are summarized below. The
comments represent stakeholder opinion(s) and may not reflect EPA's position.
• This information is not useful from a policy perspective, as it does not evaluate the technologies.
At least "tell the story" on a community basis. Things that should be included in these evaluations
include volume, flow, constituents, what the community did to address the problem, results, etc.
• Available technologies are dependent on what EPA allows communities to use, so defining the
technology type takes decisions out of municipalities' hands.
• How will the technology clearinghouse be managed?
• What about technologies used for satellite facilities?
• What about blending technologies?
• Most of the technologies were better suited to combined sewer systems. Stakeholders were concerned
that SSO control was not looked at extensively enough.
• Some pollution prevention activities should be the responsibility of the individual and not the
municipality, but municipalities still have to enforce the regulations and the ultimate responsibility is
theirs.
• EPA needs to get more specific. This report needs a discussion of the effectiveness of technologies.
• EPA needs to add data on collateral damage from implementing technologies, for example, in- or off-
line storage can lead to contamination of groundwater.
Resources Spent on CSO and SSO Control
Kevin DeBell - Office of Wastewater Management, EPA
Mr. DeBell outlined the methodological approach to this chapter which included:
• Data analysis which tabulated information of past investments in clean water infrastructure
and compiled information on what has been spent on CSO and SSO control.
• EPA's estimate of the investment needed to meet the current requirements for CSO and SSO
controls.
• EPA's acknowledgement of the fact that costs of CSO and SSO control are borne almost
exclusively by local governments and utilities but local governments and utilities have not
been requested to report the costs incurred for CSO and SSO control.
Stakeholder Questions and Comments on the Resources Chapter
Questions and comments received after the resources presentation are summarized below. The
comments represent stakeholder opinion(s) and may not reflect EPA's position.
• EPA cited funding of $9.1 billion in 1980 (in the presentation) - the stakeholder believed that
Congress never appropriated more than $2.4 billion through construction grants.
• All State Revolving Funds money has to be paid back, so these really are local expenditures, not
federal.
• At least one community had money earmarked from the federal government. EPA needs to
distinguish between local and federal expenditures.
• EPA should do an analysis of per capita costs.
• Stakeholders questioned the term "significant" with respect to past grant funding.
• Emphasize the need for grants to move things forward, especially for communities with small
populations. Expanding grant money to small communities can result in huge benefits to water
quality.
• The "knee of the curve" diagram is right on target. EPA needs to understand that it is not cost
effective to eliminate all overflows. EPA should understand how the level of CSO control compares
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Appendix B
to water quality - four overflows per year would be cost effective and we would have improved water
quality (provided that we capture the first flush). See Akron Regional Sewer District for more "knee
of the curve" information.
Make sure to reflect what caused the environmental benefits. Is it CSO and SSO prevention or
controls for other wet weather events?
There are many agencies and organizations that have done financial analyses, including the Army
Corps of Engineers
The reference to EPAs Gap Analysis is good. Stakeholders suggested that EPA include a summary of
the Gap Analysis in this report.
EPA should reference growing interest in a clean and safe water trust fund.
Qualify the reference to 106 grants and how they contribute to CSO or SSO control.
Community cost estimates are larger than in the Gap Analysis. Will both be reflected in the report?
Distinguish between points of fact and policy suggestions.
In the presentation, the Gap Analysis information was presented two different ways, make sure that
this information is presented in such a way that it can be compared. Use a common denominator.
All of the analysis is based on anecdotal evidence; there are no real data.
Put numbers in the context of per capita flow and the time frame of the project.
Estimates will be different if blending is allowed. EPA should indicate the difference in cost if
blending is allowed.
• A goal of the CSO Control Policy was to move forward with realistic plans and make sure that they
are economically sound.
Common Themes Heard During the Meeting
The following comments are paraphrases and summaries of actual stakeholder comments that emerged at
many points throughout the meeting. They reflect recurring themes. Because the statements came from
different stakeholders at the meeting, there are conflicts and disagreements among them. Additionally, all
of the comments listed below are stakeholder opinion(s) and may not reflect EPAs position.
Specific Policy and Program-Related Questions and Comments
• The report should help municipalities prioritize resources spent on CSOs and SSOs versus
other wet weather events.
• The report should help Congress make more informed decisions about wet weather issues
and other water quality issues as a whole, not just look at CSOs and SSOs in a vacuum.
• The report should help Congress prioritize funding for wet weather issues.
• The report states that there is a significant lag (25 years) between the development of water
quality laws and the comprehensive communication system regarding detecting, reporting
and tracking waterborne diseases related to water quality issues.
• Are data collected during the Report to Congress effort also being used to inform the SSO
economic analysis?
• Enforcement of the Pretreatment Rule may reduce the human health risks associated with
CSOs and SSOs, which include an industrial wastewater component. This was brought up
with regard to hospital waste.
• Does EPA have an understanding of the total costs of all of the regulations that are coming?
• Are all wet weather events extreme events? What are acceptable levels of discharge?
Across the presentations, there were questions related to the completeness, accuracy, and representation
of the information and data. While some of the comments are a product of the limited amount of
information that can be conveyed in presentation format during a two-day meeting, they are all included
here. All of the comments listed below are stakeholder opinion(s) and may not reflect EPAs position.
• Make sure that the data EPA uses are as current, correct, and complete as possible. When
a clear source of information is not apparent, feel free to provide Congress with conflicting
data, but explain them.
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• Make sure that data are unbiased in selection and presentation. On one hand, make sure
that EPA does not lead the reader to draw unsupported conclusions of the negative impacts
of CSOs and SSOs - avoid guilt by association. On the other hand, do not limit inclusion of
information and data to national-scale, complete data sets. Local information and experience
is valuable.
• Draw conclusions that are appropriate for the scale of the available data.
• Whenever possible, provide ranges in your data and interpretations in order to adequately
describe the variability. All data should be transparent and the reader should be able to
understand how EPA is using the data.
• Provide context to your information. For example, if the report states that something is 5
percent of something else, make sure that the overall universe is clear.
• Describe data in a manner that is useful to Congress, municipalities, and other stakeholders.
• Because the data are so variable and include so much anecdotal evidence, it is important to
present it in a useful way. While there may not be enough information to completely inform
policy decisions, there are conclusions that EPA should draw to help Congress, municipalities,
and other stakeholders understand the data presented. One of the biggest findings of this
report may be that we have a serious lack of data and an incomplete picture.
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Appendix B
Report To Congress
Stakeholder Meeting Attendee List
Washington D.C.
June 24-25, 2003
Name, Office/Organization
Angela Akridge, Louisville & Jefferson County Metropolitan Sewer District
David Baron, Earthjustice
Benita Best-Wong, USEPA
Steve Bieber, Metropolitan Washington Council of Governments
Joe Boles, New Iberia (Louisiana) Municipal Government
Karl Boone, ADS Corporation
Linda Boornazian, USEPA
Walter Brodtman, USEPA
Jason Brooks, Knoxville Utilities Board
Ted Brown, Center for Watershed Protection of Ellicott City MD
Thomas Brueckner, Narragansett Bay Commission
Deb Caraco, Center for Watershed Protection of Ellicott City MD
Sharie Centilla, USEPA
Shellie Chard McClary, Oklahoma Department of Environmental Quality
John Chorlog, Miami-Dade County Water and Sewer Department
Victoria Cluck, Indianapolis Department of Public Works
Gary Cohen, Hall & Associates
Hubert Colas, BPR CSO
Anna Collery, Engineering Field Activities (EFA) Chesapeake
Lamont "Bud" Curtis, The TAP Group
Kimberly V. Davis, Hazen and Sawyer
Kevin DeBell, USEPA
Mike Domenica, Black & Veatch
Gary A. DuVal, City of Richmond Public Utilities
Janet Faulk, New Iberia (Louisiana) Municipal Government
Erin Flanagan, Rockefeller Family Fund
Ruth Fontenot, New Iberia (Louisiana) Municipal Government
Peter Fortin, City of Norfolk, VA
Tom Franza, San Francisco Public Utilities Commission
Greg Frey, SRA
Wil Garland, ADS Corporation
Heather Gewandter, SRA
Paul Greenfield, University of Queensland
Frank Greenland, Northeast Ohio Regional Sewer District
Ben Grumbles, USEPA
Ahmad Habibian, Ph.D., P.E., Black & Veatch Corporation
Art Hamid, MWH Americas, Inc.
Jim Hanlon, USEPA
Eric M. Harold, RE., Buchanan Street Consulting
Marvin Hayes, Parsons
Jim Heist, CDS Technologies Inc.
Roy A. Herwig, Brown and Caldwell
John Hills, Irvine Ranch Water District
Bud Hixson, Friends of Beargrass Creek
Lisa E. Hollander, Northeast Ohio Regional Sewer District
Chris Hornback, AMSA
Carol Hufnagel, Tetra Tech
J. Leonard Ignatowski, P.E., EFA Chesapeake
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Rick Karasiewicz, PBS&J
Rachel Katonak, Michigan State University
Ifty Khan, Wastewater Collection Division, DPWES
Don Killinger, Cuyahoga County Board of Health
Carol Kocheisen, National League of Cities
Fred Krieger
Jane Lavelle
Norman E. LeBlanc, Hampton Roads Sanitation District
Stewart T. Leeth, McGuireWoods LLP
Carol Leftwich, Environmental Council of the States
Roger Lemasters, Tennessee Department of Environment and Conservation
Federico Maisch, Greeley and Hansen LLC
Linda Manning, SRA
George L. Martin, Greenwood Metropolitan District
Bob Matthews, CDM, Inc
Michael J. McCabe, Milwaukee Metropolitan Sewerage District
Nate McConoughey, Cuyahoga County Board of Health
Jane McLamarrah, MWH
Heather McTavish, American Public Works Association
James B. Meyer, Meyer & Wyatt, PC.
Sarah Meyland, Citizens Campaign for the Environment
Peter Moffa, Brown and Caldwell
Julia Moore, Limno-Tech, Inc.
John Murphy, RE., City of Bangor
Gary Nault, United States Air Force
Sharon Nicklas
Paul Novak, U.S. Environmental Protection Agency, Ohio
Jan Oliver, Allegheny County Sanitary Authority (ALCOSAN)
Laurel O'Sullivan, Lake Michigan Federation
Betsy Otto, American Rivers
Karen L. Pallansch, Alexandria Sanitation Authority
Stacy Passero, P.E., Water Environment Federation
Tom Ripp, USEPA
J. Alan Roberson, P.E., American Water Works Association
Dr. Joan Rose, Michigan State University
Nelson Ross, Tennessee Izaak Walton League
Lesley Schaaff, U.S. Environmental Protection Agency
Nancy Schultz, CH2M
Eric Seaman, Department of Natural Resources
Michael J. Sharp, Sonny Callahan and Associates, LLC
Mohsin R. Siddique, DC Water and Sewer Authority
Nancy Stoner, Natural Resources Defense Council
Mike Sullivan, Limno-Tech, Inc.
Chris Swann, Center for Watershed Protection of Ellicott City MD
Rod Thornhill, White Rock Consultants
Peter Trick, SRA
Betsy Valente, Limno-Tech, Inc.
TaraVanAtta, SRA
Lynn Vendinello, EPA, Evaluation Support Division
Mark G. Wade, P.E., Wade & Associates, Inc.
Robert C. Weaver, Kelly & Weaver, PC.
Neil Weinstein, The Low Impact Development Center, Inc.
Nancy Wheatley, Water Resources Strategies
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Appendix B
Clyde Wilber, Greeley and Hansen LLC
Gus Willis, CDS Technologies Inc.
George Zukovs, XCG Consultants Ltd.
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Appendix B
B.3. Stakeholder Meeting Summary, Huntington Beach, CA
2003 Report to Congress on the Impacts and Control of Combined Sewer
Overflows and Sanitary Sewer Overflows
Stakeholder Meeting Summary
Huntington, CA
On July 8, 2003, the U.S. Environmental Protection Agency held a meeting in Huntington Beach,
California, at the Huntington Beach Public Library to discuss the upcoming Report to Congress on the
impacts and control of CSOs and SSOs. The meeting provided an opportunity for EPA to present the
results of the data collection, request verification of information and data sources, and solicit feedback on
preliminary findings and interpretations.
The main goals of the meeting were to:
• Discuss the data, report methodology, and analyses for the 2003 Report to Congress;
• Discuss implications of the major analyses in the report; and
• Discuss participants' experiences in controlling impacts from CSOs and SSOs.
The summary below describes the presentations that outline the contents of the Report to Congress and
the resulting discussions. The summary is organized into the following major sections which correspond
to the meeting agenda:
Welcome
Goals and Agenda for the Meeting
Background on the Report
Characterization Presentation
Environmental Impacts Presentation
Human Health Presentation
Resources Spent Addressing CSO and SSO Issues
Technology Presentation
Presentation of Stakeholder Comment and Question Themes
Welcome
Benita Best-Wong - Office of Wastewater Management, EPA
Ms. Best-Wong thanked the Orange County Sanitation District for alerting EPA to the region's interest
in the Report to Congress. She mentioned that this meeting was the second of two - the first was held in
Washington, D.C., the previous week. She next answered some of the questions that were repeatedly heard
at the previous meeting but would not be covered during the presentations.
Ms. Best-Wong gave updates on the blending issue, the SSO Rule, and the Storm Water Phase II Rule.
Ms. Best-Wong next touched on the desire of Assistant Administrator for Water, Tracy Mehan, to ensure
policy that facilitates a watershed approach. He would like EPA to focus on efficient ways of doing things
and be aware of areas where EPA can help municipalities economize and make the best decisions possible.
She went on to say that EPA hopes to focus on environmental outcomes, such as water quality and
swimmer safety, and not outputs. She reminded the participants that the information gathered for this
report forms a baseline and is something from which to work. EPA hopes that the report can be used not
only to inform decision making but also for stakeholders to use as a resource.
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Goals and Agenda for the Meeting
Linda Manning - Facilitator, SRA International
Ms. Manning began by setting "ground rules" for the meeting. The ground rules were as follows:
• Do not repeat points. This meeting is simply a way to collect perspectives and the number of
times a comment was made will not be presented.
• Remember that participants are only being presented with representational data.
• Please provide us with additional information sources.
• Remember that this is the first effort to pull together all available information on this topic.
The data are incomplete.
Background on the 2003 Report to Congress
Kevin DeBell - Office of Wastewater Management, EPA
Mr. DeBell presented the background to the 2003 Report to Congress. He started by mentioning
the near-term EPA policies that directly led to the request for the 2003 Report to Congress. First, he
described the 1994 National CSO Control Policy which formalized EPA's management expectations for
CSS communities. Next, a summary of the 2001 Report to Congress - Implementation and Enforcement
of the Combined Sewer Overflow Control Policy was presented. This report acted as a program evaluation
in which success of CSO Control Policy implementation was assessed; one useful product of the 2001
Report is the CSO database, which includes information on all CSO permits. Mr. DeBell then mentioned
the draft SSO Notice of Proposed Rulemaking, and the 2000 Wet Weather Water Quality Act, which
required the 2003 Report. The statutory requirements for the 2003 Report are stated below:
The Administrator of the Environmental Protection Agency shall transmit to Congress a report
summarizing:
a. the extent of human health and environmental impacts caused by municipal combined sewer
overflows and sanitary sewer overflows, including the location of discharges causing such
impacts, the volume of pollutants discharged, and the constituents discharged;
b. resources spent by municipalities to address these impacts; and
c. an evaluation of the technologies used by municipalities to address these impacts.
Mr. DeBell next explained that EPA is not required to have a public review of reports to Congress, but
that this particular program has a legacy of stakeholder collaboration, which EPA values.
Finally, Mr. DeBell acknowledged the research team and presented the report outline. The Report to
Congress is organized as follows:
Introduction
Background
Methodology
Characteristics of CSOs and SSOs
Environmental Impacts of CSOs and SSOs
Human Health Impacts of CSOs and SSOs
Federal and State Actions to Control CSOs and SSOs
Technologies Used to Reduce the Impacts of CSOs and SSOs
Findings and Recommendations
Stakeholder Questions and Comments on the Background Presentation
Questions and comments received after the background presentation are summarized below. The
comments represent stakeholder opinion(s) and may not reflect EPA's position.
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Appendix B
• Is EPA taking this opportunity to weigh in on the blending rule?
• In the Wet Weather Water Quality Act of 2000, is there a context for larger wet weather events in the
act language?
Characterization of CSOs and SSOs
Kevin DeBell - Office of Wastewater Management, EPA
Mr. DeBell presented data on the location of CSO and SSO discharges, the volume of pollutants
discharged, the constituents discharged, and the frequency of discharge events.
This presentation defined a CSO as a mixture of untreated sewage and storm water discharged from a
combined sewer system at a point prior to the headworks of the POTW. Generally, CSOs occur during
wet weather when the CSS becomes overloaded. SSO is defined as a discharge of untreated or partially
treated wastewater from a sanitary sewer system at any point prior to the headworks of a POTW.
Backups of wastewater to private property are not included in the definition of SSO used for this Report
to Congress.
Data Sources for the Characterization Chapter
EPA used the following data sources to characterize CSOs and SSOs.
State databases for tracking CSO and SSO events;
NPDES permit files;
Approximately 80 interviews with state and municipal officials;
LTCPs and other capital improvement documentation;
Literature review; and
Existing EPA documentation, including technical reports and products of cooperative
agreements.
Key Research Questions for the Characterization Chapter
This presentation introduced three key research questions for the characterization chapter:
• How many NPDES permits exist for combined sewer systems and sanitary sewer systems?
• What are the common pollutants found in CSOs and SSOs?
• What are the volume, frequency, and location of CSOs and SSOs?
Stakeholder Questions and Comments for the Characterization Chapter
A list presenting the questions and comments received after the characterization presentation are
summarized below. The comments represent stakeholder opinion(s) and may not reflect EPA's position.
• The term "basement backup" is misleading. EPA should replace it with "private property" backup, as
many areas of the county do not have basements. The critical link in this phenomenon is the laterals.
Private citizens do not know how to clean the laterals and plumbers do not report the problem.
• EPA needs to highlight the lack of consistency between different jurisdictions. There is no baseline
for SSO reporting. It is important to let Congress understand that this information is missing.
• Look at WERF reports for other estimates on pollutant concentrations and other CSO/SSO
characteristics.
• Differentiate between major and minor sources.
• Make sure to assess benefits versus the costs of elimination, so that we know where we can best put
our resources to help the environment.
• Can the federal government fund this collection system program like they did for secondary
treatment? Municipalities cannot do it.
• Stakeholders commented that communities had SSO tracking systems.
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• How were sewer systems rated in the report? Some stakeholders wanted to know if they would be
able to see how their system compared to a national average.
• Characterize SSO by volume per 100 miles of pipe in order to compare systems.
• Present SSO events by cause. EPA may also want to break out events regionally. Doing this will help
identify extreme weather events.
• SSO should only be defined based on what agencies are responsible for (i.e., agencies are not
responsible for all laterals).
• It will be very difficult to compare systems nationally, due to the differences in reporting
requirements.
• In the slides, how do the volume and frequencies of SSOs compare to the amount of sewage
collected?
• Is EPA distinguishing between the SSO effluent that actually gets to surface water versus how much is
collected and disposed of properly?
• Does EPA have details about how many of the SSOs in the database were due to wet weather and I/I?
• It is not possible to design sewers based on every potential storm event. The report should address
what can not be contained in the system.
• The conclusion "On a local scale, pollutant loads from CSOs and SSOs can be significant"- the
opposite can also be true. On a local scale, pollutant loads may not have significant impacts.
• Regarding reporting thresholds, maybe there is a reason for thresholds, the report should discuss the
rationale.
• Excluded from the study is storm water, but a significant source of pathogens found in storm water
are from SSOs.
• Need to understand the water quality issues in receiving waters.
• In the SSO database, has EPA identified repeated, chronic, or preventable spills? Sewage collection
agencies are responsible for these incidents and they need to correct them. This type of spill may
skew or misrepresent the real problem.
• EPA could describe money spent versus pipe miles versus spills to compare communities.
• What percent of the spills reach receiving waters? A stakeholder said that during wet weather, very
little of the amount spilled was contained, but during dry weather most was contained.
• Stakeholders mentioned that flood control systems are designed to withstand 195-year floods but
there are no standards for sewer systems.
• Stakeholders said that the report needed to focus on impacts and focus on specifics.
Environmental Impacts of CSOs and SSOs
Hans Holmberg - Limno-Tech, Inc.
Mr. Holmberg began by defining "environmental impacts" as water quality, aquatic life, and aesthetic
impacts that affect designated uses. Violations of water quality standards were used as an indicator
for environmental impacts. While researching this chapter, EPA used previously completed national,
state, and local assessments. Literature and web searches were performed and interviews with state and
municipal officials were carried out.
EPA sought to characterize types of environmental impacts from CSOs and SSOs. First, EPA presented
ranges in concentrations of the constituents typically found in CSOs and SSOs. EPA presented the results
of assessments of environmental impacts caused by CSOs and SSOs. They acknowledged that while
beach closures and shellfish bed closures have been traced to CSOs and SSOs, the data are not complete.
EPA described planned national assessments in which CSO outfall locations will be integrated with EPAs
WATERS database. This will allow CSO locations to be associated with information such as 303(d)
impaired reaches and drinking water intakes.
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Appendix B
Conclusions for the Environmental Impacts Chapter
EPA presented preliminary conclusions regarding the environmental impacts from CSOs and SSOs.
These included:
• CSOs and SSOs contain pollutants that cause impairments to designated uses, as reported in
national assessments.
• CSOs and SSOs can be a principal cause or a contributing cause of an environmental impact.
• National data are inconsistent in tracking CSOs and SSOs as a direct cause of impairment.
• While data are not comprehensive, some national estimates of use impairment have been
made.
• State and local examples of cause and effect exist where CSO and SSO reporting and tracking
are undertaken.
EPA asked the stakeholders present at the meeting for additional information on documented
environmental impacts from CSOs and SSOs.
Stakeholder Questions and Comments on the Environmental Impacts Chapter
Questions and comments received after the environmental impacts presentation are summarized below.
The comments represent stakeholder opinion(s) and may not reflect EPA's position.
• Most impacts seem very locally specific.
• Because of the ambiguity of the data, should you split them into separate categories in order to direct
policy talks and funding allocations?
• There may be a time lapse between the event and the environmental impact. Does the report
measure that?
• The beach closure chart should clarify miles by including the total miles of beach.
• Is EPA saying that municipal point sources, specifically CSOs and SSOs, are leading sources of water
quality impairment?
• Stakeholders said that within their jurisdictions, a significant amount of water contamination is due
to failing septic tanks.
• Stakeholders thought that EPA should try to gain an understanding of the concentration of pathogens
from SSO to storm water, which leads to beach closing.
• Distinguish between beach advisories, which (in California) are based on bacteria levels from ongoing
water quality monitoring, and beach closures, which (in California) happen after every reported SSO/
CSO event.
• For SSO, EPA cannot blame natural phenomenon, such as rain and snowmelt, for overflows.
Human Health Impacts of CSOs and SSOs
Heather Gewandter - SRA International
Ms. Gewandter began by introducing the key questions addressed in this chapter:
• What constituents of CSOs and SSOs cause human health impacts?
Of what consequence are these impacts?
• Which exposure pathways are the most significant and what populations are most sensitive?
• What are the impediments to understanding the linkages between CSOs and SSOs, exposures,
and the human health impacts?
• What is the institutional framework to assess and address potential human health impacts of
CSOs and SSOs?
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Ms. Gewandter explained that EPA first performed an extensive literature review. Then, EPA held an
experts workshop in order to verify the accuracy of data already collected, find new sources, and ascertain
an understanding of experts' opinions of the human health impacts of CSOs and SSOs. EPA next
performed a series of state and community interviews for the purpose of understanding local and state
health agency staff's opinions of the impacts of CSOs and SSOs and to characterize the current activities
being carried out that address this potential threat.
Ms. Gewandter went on to present the range of human health symptoms resulting from exposure to the
pollutants typically found in CSOs and SSOs. Next, she discussed exposure pathways and the groups
facing the most frequent exposure, as well as the groups most sensitive to waterborne illnesses.
Ms. Gewandter described the limitations of the major data sources used to identify and describe
waterborne disease outbreaks, one potential indicator of human health impacts from CSOs and SSOs.
She next presented local, site specific examples outbreaks attributed to exposure to sewage in order to
illustrate the potential for acute health impacts.
Next, EPA outlined the challenges to identifying the human health impacts of CSOs and SSOs. These
include:
• The lack of connectivity in the monitoring and reporting systems for CSO and SSO events,
human exposures, and human health impacts.
Difficulty identifying the source of pathogens.
The difficulty in attributing disease outbreaks to CSO and SSO events.
The fact that outbreak reporting to CDC is voluntary.
The understanding that many people who become ill do not seek medical treatment due to
the nature of the illness.
There are inconsistent probabilities of diagnoses within the health care system.
The general tendency towards underreporting.
Conclusions for the Human Health Impacts Chapter
Finally, Ms. Gewandter identified the actions that are currently being taken by state and local governments
to address the human health impacts from CSOs and SSOs and EPA's preliminary conclusions. These
conclusions include:
• The pathogens and pollutants found in CSOs and SSOs have the potential to cause human
health impacts.
• Exposures to the pathogens and pollutants resulting from CSOs and SSOs occur, but are
difficult to quantify.
• Human health impacts from waterborne diseases are underreported.
• Responsibilities for protecting human health from waterborne illnesses are distributed among
many agencies and institutions.
Stakeholder Questions and Comments on the Human Health Impacts Chapter
Questions and comments received after the human health impacts presentation are summarized below.
The comments represent stakeholder opinion(s) and may not reflect EPA's position.
• Comment on warnings: In California, in event of SSO, beaches close immediately and there is no lag
time.
• Clarify between postings, advisories, and closures.
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Appendix B
• CDC released a paper in 1999 that said there were 300 cases of Cryptosporidiosis annually. This is
contradictory to the information EPA presented and shows that there is a lot of uncertainty.
• The information regarding sensitive populations is all speculation.
• EPA needs to distinguish between large and small potential exposures; break out one-time exposure
risk (metals) versus chronic exposures.
• There are no criteria for metals for recreational use.
• Just because a person has Cryptosporidiosis does not mean they get sick.
• Did EPA coordinate with the new epidemiology studies?
• Did EPA do risk assessment with pathogen data? Has EPA put the risk (of health impacts from CSO
and SSO) in context with other risks?
• Did the literature review find epidemiological studies on WWTP workers? Did they build immunity?
• The material is inconclusive.
• Tie in anticipated exposure levels.
• Make sure to qualify that the pathogens and pollutants are coming from human waste and wastewater
in the table.
• If groundwater impacts are a concern, many parameters are attenuated.
Resources Spent on CSO and SSO Control
Kevin DeBell - Office of Wastewater Management, EPA
Mr. DeBell outlined the methodological approach to this chapter which included:
• Data analysis which tabulated information of past investments in clean water infrastructure
and compiled information on what has been spent on CSO and SSO control.
• EPA's estimate of the investment needed to meet the current requirements for CSO and SSO
controls.
• EPA's acknowledgement of the fact that costs of CSO and SSO control are borne almost
exclusively by local governments and utilities but local governments and utilities have not
been requested to report the costs incurred for CSO and SSO control.
Stakeholder Questions and Comments on the Resources Chapter
Questions and comments received after the resources presentation are summarized below. The comments
represent stakeholder opinion(s) and may not reflect EPA's position.
• Are SSO control expenditure needs distinguished from overall needs?
• Is the cost EPA has designated as SSO cost incremental or is it the total cost of running the sewage
collection system? Since all money spent on the sewage collection system is aimed at getting sewage
to the plant and preventing sewage spills, the total number may be more accurate.
• Do you plan to use other financial studies besides EPA's Gap Analysis (i.e., Waste Infrastructure
(WIN) report)? The two studies have contradictory findings and a stakeholder did not want
Congress to be confused if it heard the findings from the WIN report and they were not mentioned
in this report.
• Stakeholders were concerned about private spills. Since municipalities do not pay for those, some
stakeholders did not want them included, or they wanted these estimates to at least be called out.
Technologies for CSO and SSO Control
Kevin DeBell - Office of Wastewater Management, EPA
Mr. DeBell described the key data sources for the technology chapter. These included:
• Extensive literature reviews of existing EPA documentation as well as other sources;
• Interviews with municipal officials;
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Report to Congress on the Impacts and Control ofCSOs and SSOs
• Meetings with key EPA staff; and
• Informal peer review by internal and external experts.
Key Questions for the Technologies Chapter
Mr. DeBell introduced the key questions that were addressed:
• What technologies have been used by municipalities to control CSOs and SSOs?
• What factors influence the effectiveness of these technologies?
• Have there been any recent technological innovations in the control of CSOs and SSOs?
While researching this chapter, EPA identified common and promising technologies used by
municipalities to address CSOs and SSOs. From this research, EPA developed technology descriptions
summarizing available technologies and factors influencing their effectiveness. Mr. DeBell explained that
it is very difficult to compare certain types of technologies, as they are designed to deal with different
aspects of wet weather challenges. Therefore, the technologies were not ranked for effectiveness against
each other within this chapter.
Presentation of Technologies
Mr. DeBell said that a wide range of technologies are available and that, within the report, they had been
grouped into five key categories:
Operations and maintenance activities;
Collection system controls;
Storage facilities;
Treatment technologies; and
Low impact development techniques.
Mr. DeBell mentioned that EPA developed case studies on each of the researched technologies and
presented preliminary findings pertaining to the relative cost of implementing the systems, the type of
system for which the technology was designed, and the pollutants or problems controlled.
Stakeholder Questions and Comments on the Technologies Chapter
Questions and comments received after the technologies presentation are summarized below. The
comments represent stakeholder opinion(s) and may not reflect EPA's position.
• There is a lack of innovative technologies investigated, especially the decentralized technologies.
• Did EPA discuss odor control?
• What about the fats, oils, and grease requirements, will they be included in the SSO rule?
• Do you have any understanding about the total cost of all of the regulations that are coming?
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Appendix B
Report To Congress
Stakeholder Meeting Attendee List
Huntington Beach, CA
July 8, 2003
Name, Office/Organization
Andy Aguilar, Surfrider Foundation
Richard Alcorn, City of Rancho Cucamonga
Jody Allen, Sacramento County
Ric Amador, City of San Diego
Rodney Andersen, City of Burbank
Nick Arhontes, Orange County Sanitation Districts
Daniel Askenaizer, MWH
Regan Bailey, City of Riverside
Dennis Baker, Earth Resource Foundation
Richard Bardin, Boyle Engineering Corporation
Danilo Batson, City of Glendale
Cindy Beck, Irvine Ranch Water District
Matthew Bequette, City of Los Angeles
Benita Best-Wong, USEPA
Thomas Blanda, Orange County Sanitation Districts
M. Todd Broussard, City of Huntington Beach
Bryan Brown, City of Los Angeles
Ray Burk, City of Santa Ana
Ed Burt, City of Newport Beach
John Butcher, NCPI
Olson Childress, City of Chino Hills
Marvin Chiong, Los Angeles County Department of Public Works
James Clark, Black & Veatch
Daniel Cooper, Lawyers for Clean Water
Lee Cory, Yorba Linda Water District
Kevin DeBell, USEPA
Jim Delicce, City of Newport Beach
Bill Denhart, City of San Diego
Parivash Dezham, Inland Empire Utilities Agency
Dick Dietmeier, South Coast Water District
Rick Donahue, City of San Diego
Mike Dunbar, South Coast Water District
Bill Echols, Central Contra Costa County Sanitary District
Michele Farmer, Orange County Sanitation Districts
Tom Fauth, Costa Mesa Sanitary District
Michael Feroz, Jacobs Civil Inc.
Ken Fischer, City of Burbank
Michael Flores, HDR
Paul Forsthoefel, ADS Environmental Services
Phil Friess, LACSD
Kevin Gensler, City of San Diego
Heather Gewandter, SRA
Marco Gonzalez, Surfrider Foundation
Chris Gray, City of Huntington Beach
Don Greek, DGA Consultants
Ken Greenberg, U.S. EPA, Region 9
Paul Guzman, Costa Mesa Sanitary District
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Roy Hafar, City of Folsom
Roger Ham, Union Sanitary District
Robin Hamers, Costa Mesa Sanitary District
Daniel Hardgrove, City of Glendale
Alan Harrell, Coachella Valley Water District
E Patrick Hassey, Sacramento County
Jonathan Hasson, ADS Environmental Services
Brent Hayes, Garden Grove Sanitary District
Jeannie Heimberger, City of Fountain Valley
Penny Hill, Los Angeles County Sanitation Districts
Hans Holmberg, Limno-Tech, Inc.
Larry Honeybourne, County of Orange
Lisa Marie Kay, MEC Analytical Systems Inc.
Zeki Kayiran, AKM Consulting Engineers
Bill Knitz, DGA Consultants
Ruth Kolb, City of San Diego
Bob Kreg, Southern California Alliance of Publicly Owned Treatment Plants
Patty Lambaren, City of Fullerton
Winnie Lee, PBS&J
Sylvie Lee, Inland Empire Utilities Agency
Albert Lee, Jr., City of Glendale
Keith Linker, City of Anaheim
Russell Maguire, City of Anaheim
Linda Manning, SRA
Lisa Mattert, City of Orange
Ziad Mazboudi, City of San Juan Capistrano
Monica Mazur, County of Orange
Joe McDivitt, South Coast Water District
Charles McGee, Orange County Sanitation Districts
Patrick McNelly, Orange County Sanitation Districts
Dayna Michaelsen, Midway City Sanitary District
Victor Moraga, City of Ontario
Andy Morrison, Union Sanitary District
Margie Nellor, Sanitation Districts of Los Angeles County
Bryan Ortega, City of Glendale
Ralph Palomares, El Toro Water District
Diann Pay, AKM Consulting Engineers
Ken Payne, City of Folsom
John Perry, City of San Bernardino
Michele Pla, CH2M Hill
Denis Pollock, MGD Technologies Inc.
Craig Proctor, Inland Empire Utilities Agency
Lloyd Prosser, EMA
Ronn Rathbun, City of Huntington Beach
Robert Reid, West Valley Sanitation District
Don Rhoads, Central Contra Costa County Sanitary District
Kenny Robbins, Midway City Sanitary District
Manuel Romero, City of Santa Barbara
Dick Runge, South Coast Water District
Jeff Sadler, EGA
Dale Schindler, Crestline Sanitation District
Kathy Schindler, Crestline Sanitation District
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Appendix B
Don Schulz, Surfrider Foundation
John Shaffer, Environmental Engineering & Consulting
David Shissler, City of Laguna Beach
Mike Shope, Camp Pendleton
Gary Skipper, MGD Technologies Inc.
Mary Snyder, County of Sacramento
Stan Steinbach, Environmental Engineering & Consulting
Ken Theisen, California Regional Water Quality Control Board
Leo Truttmann, ETEC
Roger Turner
TaraVanAtta, SRA
Clarence Van Corbach, City of Manhattan Beach
Gonzalo Vazquez, City of Cypress
Konya Vivanti, Garden Grove Sanitary District
Jeff Walker, City of Chino Hills
Dan Wall, City of Burbank
Stephanie Warren, Surfrider Foundation
Jason Wen, City of Downey
Dave Williams, East Bay Municipal Utility District
James Wilson, City of Fresno
Rick Wilson, Surfrider Foundation
Hu Yi, Los Angeles County
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Appendix C
Documentation of State and
Municipal Interviews
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Appendix C
Documentation of State and Municipal Interviews
Data collection for this report involved a series of site visits and telephone interviews. Such data collection efforts
were conducted in accordance with an Information Collection Request (ICR 2063.01), which was approved by
OMB on September 16, 2002 (OMB No. 2040-0248).
Site Visits
EPA conducted site visits to seven states to obtain specific information regarding CSOs and SSOs for the report.
The states visited include Connecticut, Kansas, Maryland, Missouri, North Carolina (SSO only), Oklahoma (SSO
only), and Rhode Island. While there, EPA met with permitting staff to discuss programmatic issues related to
CSO and SSO discharges. EPA also accessed the NPDES authority's electronic data management system for SSOs,
where available.
North Carolina was specifically visited to obtain information on its collection system permitting program.
Oklahoma was selected for a site visit to collect information on the state's collection system program used to
address SSOs and other sewer system issues. The five states with both CSSs and SSSs- Connecticut, Kansas,
Maryland, Missouri, and Rhode Island- were selected for site visits, because CSO permit file reviews were not
conducted in these states for the 2001 Report to Congress-Implementation and Enforcement of the CSO Control
Policy (EPA 2001). The information gathered from these states was used to update the inventory of CSO outfalls,
documented in Appendix D of this report.
EPA also conducted site visits to regional offices, municipal governments, sewer utilities and non-governmental
organizations. EPA visited EPA Region 4 offices in Atlanta, GA, to collect pertinent information about the region's
Management, Operation and Maintenance (MOM) program, and to review program files. EPA conducted site
visits to Orange County and San Francisco, California. In Orange County, EPA met with the Orange County
Sanitation District to gather SSO information and met with the Orange County Health Care Agency to collect
beach monitoring data (including beach closings and postings). In San Francisco, EPA met with the San
Francisco Public Utilities Commission to discuss CSO and environmental impact data. Moreover, EPA met with
Save the Bay in Rhode Island and Heal the Bay in the greater Los Angeles-area to collect CSO and SSO-related
information.
Public Health State and Municipal Phone Interviews
EPA also conducted interviews with public health personnel. State or territorial epidemiologists and local public
health officials were the primary sources of data. During these interviews, EPA gathered data on pathogen
sources, contaminated water exposures, and illness tracking. In addition, EPA inquired about innovative local
programs in place to monitor CSOs or SSOs and/or waterborne illnesses. Through these interviews, EPA sought
a clearer understanding of the roles and responsibilities of these agencies in preventing, tracking, and monitoring
potential human health impacts associated with CSO and SSO discharges within their jurisdiction.
States and communities were selected from each EPA region in an attempt to ensure geographic, climatic, and
population variability among communities interviewed. Nevertheless, the sample was intentionally biased,
targeting communities that were likely to have health data related to CSOs and SSOs, or which employed
noteworthy water quality monitoring or waterborne disease outbreak tracking techniques. In total, officials from
even states and 23 municipalities, as shown in Appendix I, were interviewed.
C-1
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
CSO and SSO Municipal Telephone Interviews
In order to gather representative information to characterize CSOs and SSOs, EPA interviewed officials with 85
sewer agencies, 40 with CSSs and 45 with SSSs, which varied widely in terms of service area, population served,
and sewer age. For example, EPA interviewed officials representing systems that served as few as 75 people
to systems that served over one million people. In total, EPA interviewed municipal officials in 27 states by
telephone. In some states, both CSO and SSO interviews were conducted. State NPDES authorities were contacted
in advance of any interviews conducted within their states. At that time, EPA briefly interviewed state officials to
gather information about environmental and human health impacts as well as cost information relevant to CSO
and SSO discharges.
Potential CSO and SSO interviewees was selected as follows. For the CSO interviews, a list of CSO permittees that
had developed and/or implemented CSO controls were extracted from the inventory of CSO permits (Appendix
D). A list of unique entities with SSSs, which have reported at least one SSO, was extracted from the SSO data
management system described in Appendix G. SSO communities studied in EPA fact sheets (EPA 2003) were
excluded from consideration. A random sampling was taken from the CSO and SSO lists to create the pool of
potential interviews. Municipal officials unable or unwilling to participate in the survey were replaced with
alternate candidates.
Through the CSO interviews, EPA gathered information about collection systems, treatment plants (if applicable),
operational responsibility, CSO events, environmental and human health impacts from CSO discharges, LTCP
implementation, and funding. As part of the SSO interviews, EPA collected information about collection systems,
treatment plants (if applicable), operational responsibility, SSO events, environmental and human health impacts
from SSO discharges, O&M, and funding.
References
EPA. 2003. Office of Water. "Featured Factsheets, Case Studies, and Other Information." Retrieved October 3,
2003. http://cfpub2.epa.gov/npdes/sso/featuredinfo.cf.
EPA. 2001. Office of Water. Report to Congress- Implementation and Enforcement of the Combined Sewer Overflow
Control Policy. EPA833-R-01-003.
C-2
-------
Appendix D
List of Active CSO Permits
-------
-------
Appendix D
List of Active CSO Permits, Sorted by Region and State
• EPA
Region
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
State
CT
CT
CT
CT
CT
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
NPDES Permit
Number
CT01 00056
CTO 100251
CTO 100366
CT0100412
CT0101010
MA01 02997
MA0101168
MA0101192
MA0101338
MA0101621
MA0101877
MA0101974
MA01 00986
MA01 02351
MA0101508
MA01 03331
MA0101982
MA0 100455
MA0101630
MA01 00897
MA0 100 137
MA01 00382
MA0 100447
MA01 00552
MA0 100625
MA01 00633
MA01 00781
ME01 00625
ME01 00633
ME01 02369
ME0100617
ME0100951
ME0100781
ME01 00846
ME01 00854
ME01 00722
ME0101117
ME0101214
ME0101478
ME0101494
ME0101681
ME01 02075
ME01 00595
ME0101702
ME01 00897
ME0101532
ME0100153
ME0 102466
MEU508074
ME0101435
ME01 00005
ME0100013
ME0100021
Facility Name
Bridgeport-West WPCF
Hartford MDC WPCF
New Haven East Shore WPCF
Norwich WPCF
Bridgeport-East WPCF
Worcester Combined Overflow Facility
Palmer WPCF
Boston Water and Sewer Commission
Town of Ludlow CSOs
Haverhill WWTF
Chelsea
City of Cambridge
Fitchburg WWTF
MWRA, Deer Island WWTP
Chicopee WPCF
Springfield CSOs
Somerville DPW
South Hadley WWT
Holyoke WPCF
Taunton WWTPs
Montague WPCF
Fall River WWTP
Greater Lawrence Sanitary District
Lynn WWTF
Gloucester WPCF
Lowell Regional WWU
New Bedford WWTF
Skowhegan WPCP
City of South Portland
Fort Kent Utility District
Sanford Sewerage District
Paris WWTP
Bangor WWTP
Westbrook/Portland Water District
Kennebec Sanitary District
Winslow Sanitary District
Saco WWTP
Bar Harbor WWTF
Lewiston-Auburn WPCA
Fairfield
Madawaska PCF
Portland Water District
Rockland WWTF
City of Gardiner
Hamden
Belfast WWTF
Corrina Sewer District
Bar Harbor Hulls Cove
Randolf
City of Portland
Auburn Sewerage District
Augusta Sanitary District
Bath WWTP
32
44
19
15
12
1
6
37
1
21
4
11
27
14
31
25
2
3
15
1
2
19
5
4
5
9
35
9
8
1
2
1
12
5
3
2
5
3
1
2
2
23
4
2
1
2
1
1
1
12
6
24
4
D.1
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
EPA
Region
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
State
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
NH
NH
NH
NH
NH
NH
Rl
Rl
Rl
VT
VT
VT
VT
VT
VT
VT
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NPDES Permit
Number
ME01 00048
ME01 00072
ME0100501
ME01 00994
ME0100196
ME01 00285
ME0100307
ME01 00323
ME0100391
ME01 00439
ME0100471
ME01 00498
ME01 00111
NH01 00234
NH01 00366
NH0100871
NH0100170
NH0100013
NH01 00447
RI01 00072
RI0100315
RI01 00293
VT0100153
VT0100196
VTO 100285
VTO 100374
VTO 100404
VT01 00579
VT01 00871
NJ0108731
NJ01 08766
NJ0021016
NJ0111244
NJ01 08782
NJ0109118
NJ0108791
NJ0108812
NJ01 08847
NJ0108871
NJ01 08880
NJ01 08723
NJ01 08758
NJ0025321
NJ01 09240
NJ01 17846
NJ0020028
NJ0020141
NJ0020141a
NJ0020591
NJ0024741
NJ0024643
NJ0108715
Facility Name
Biddeford Wastewater Department
City of Brewer
Town of Dover-Foxcroft Wastewater Department
Lewiston
Town of East Millinocket
Town of Kittery
Lisbon WWTF
Machias WWTP
Mechanic Falls Sanitary District
Milo Water District
Old Town PCF
Orono Water Pollution Control Facility
Bucksport WWTF
City of Portsmouth
City of Lebanon WWTF
Exeter
Nashua WWTF
Berlin PCF
City of Manchester WWTF
Narragansett Bay - Bucklin
Narragansett Bay - Fields Point
Newport City Hall
Burlington Main WWTF
Montpelier WWTF
Randolph WWTF
Springfield WWTF
Vergennes WWTF
St. Johnsbury WWTF
Rutland WWTP
City of Rahway
City of Hackensack
Passaic Valley Sewerage Commissioners
Town of Kearny
City of Elizabeth
Ridgefield Park Village
Camden County MUA
City of Camden
Gloucester City
Town of Harrison
City of Paterson
Jersey City MUA
Newark
North Hudson SA-West NY (River Road)
City of Bayonne CSOs
East Newark
Bergen County WWTP Utilities Authority
Middlesex County Utility Authority
Perth Amboy
Edgewater MUA
Joint Meeting of Essex & Union Counties
Rahway Valley Sewerage Authority
Guttenberg Town
Number of
Outfalls
11
7
4
30
1
3
2
2
1
3
3
1
2
2
6
1
8
1
22
28
45
3
1
15
3
21
0
19
3
0
2
0
10
33
6
1
31
7
7
31
27
27
2
28
1
0
0
16
0
0
0
1
D.2
-------
Appendix D
1
1
EPA
Region
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
State
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NPDES Permit
Number
NJ0026085
NJ0026182
NJ0029084
NJ0034339
NJ0034517
NJ01 08707
NJ0020923
NJ01 08898
NY0027081
NY0029114
NY0029106
NY0029050
NY0028410
NY0028339
NY0027961
NY0248941
NY0027545
NY0029807
NY0027073
NY0027057
NY0026689
NY0026336
NY0026310
NY0027766
NY0031208
NY01 83695
NY0099309
NY0087971
NY0036706
NY0035742
NY0033545
NY0029173
NY0031429
NY0029351
NY0031194
NY0031046
NY0030899
NY0029939
NY0029831
NY0026247
NY0033031
NY0020818
NY0026280
NY0023981
NY0023256
NY0022403
NY0022136
NY0022039
NY0024481
NY0021873
NY0025747
NY0020621
Facility Name
North Hudson SA-Hoboken (Adams Street)
Camden County MUA
North Bergen MUA (Woodcliff)
North Bergen MUA (Central)
Fort Lee
Passaic Valley Sewerage Commissioners
Trenton Sewer Utilities Authority
North Bergen MUA (Central)
Syracuse Metro WWTP
City of Oswego, East Side STP
Oswego-West Side STP
Glens Falls WWTP
Bird Island WWTF
Frank E. VanLare STP
Dunkirk WWTP
City of Mechanicville CSO
Clayton Village WTF
Canastota WPCF
Red Hook WPCP
Lockport WWTP
Yonkers Joint WWTP
Niagara Falls WWTP
Newburgh WPCP
Lewiston Master S.D.
Dock Street STP
Washington County S.D. 2
Troy CSO
Rensselaer County
Ticonderoga S.D. #5 WPCP
Chemung County-Elmira S.D. STP
Village of Coxsackie STP
Waterford WWTP
Utica CSO
Kingston WWTF
Massena WWTP
Cohoes CSO
Watervliet CSO
Tupper Lake WPCP
Ogdensburg WWTP
North River WPCF
Green Island CSO
Potsdam WPCP
North Tonawanda WWTP
Village of Johnson City CSO
Village of Holley STP
Little Falls WWTP
Erie County S.D. #6
Hudson STP
Lewiston ORF
Medina WWTP
Albany CSO
Wellsville WWTP
Number of I
Outfalls ^^^^1
11
1
1
0
2
0
1
9
62
6
1
1
58
6
1
3
2
1
34
30
26
9
12
1
0
11
49
0
2
11
3
4
82
7
10
16
5
3
17
50
3
1
13
2
0
3
1
10
1
13
12
3
D.3
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
• EPA
Region
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
State
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
DC
DE
MD
MD
MD
MD
MD
MD
MD
MD
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
NPDES Permit
Number
NY0020516
NY0020494
NY0020389
NY0020290
NY0020117
NY0021903
NY0026131
NY0026239
NY0026221
NY0026204
NY0026191
NY0026182
NY0026174
NY0024406
NY0026158
NY0026255
NY0026115
NY0026107
NY0026026
NY0026018
NY0025984
NY0025780
NY0026166
NY0026212
DC0021199
DE0020320
MD0067547
MD0021571
MD0021598
MD0021601
MD0021636
MD0067384
MD0067407
MD0067423
PA0036820
PA0036650
PA0028673
PA0028631
PA0028436
PA0028223
PA0039489
PA0028401
PA0037044
PA003771 1
PA0028207
PA0038920
PA0027421
PA0042234
PA0043273
PA0043877
PA0043885
PA0070041
Facility Name
Schenectady WPCP
Boonville WWTP
Catskill WWTP
Amsterdam WWTP
Gouverneur STP
Auburn STP
Wards Island WPCP
Tallmans Island WPCP
NYCDEP Rockaway WWTP
Newtown Creek WPCP
NYCDEP-Hunt's Point WPCP
NYCDEP Coney Island WPCP
NYCDEP Oakwood Beach WPCP
Binghamton CSO
NYCDEP Bowery Bay WPCP
Poughkeepsie WPCP
NYCDEP Jamaica WPCP
Port Richmond WPCF
Rensselaer CSO
Pittsburgh WPCP
Watertown WPCP
Oneida County WPCP
NYCDEP Owls Head WPCP
NYCDEP 26th Ward
District of Columbia WWTP
Wilmington
LaVale CSOs
Salisbury City
Cumberland WWTP
Patapsco WWTP
Cambridge WWTP
Western port Town
Allegany County CSOs
Frostburg CSOs
Galeton Borough Authority
Titusville City
Borough of Gallitzin WWTP
Mid-Cameron Authority
Elizabeth Borough STP
Corry City Municipal Authority
Garrett Boro SIP
Dravosburg Borough STP
Ford City WTP
Everett Borough Municipal Authority
Reynoldsville Sewer Authority
Burnham Borough
Norristown MWA
Kittanning Borough STP
Hollidaysburg Regional WWTP
Greater Pottsville Area Sewer Authority (West End)
Greater Pottsville Area Sewer Authority
Mahanoy City (MCSA) STP
Number of I
Outfalls ^^^^1
2
1
6
3
1
9
78
21
27
85
42
4
1
10
49
6
6
36
8
14
17
1
16
4
60
40
3
2
18
1
14
2
3
15
4
4
6
1
6
3
2
1
3
5
7
4
2
9
4
4
56
3
D.4
-------
Appendix D
• EPA
Region
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
State
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
NPDES Permit
Number
PA0037818
PA0027227
PA0027049
PA0027057
PA0027065
PA0027081
PA0027090
PA0027103
PA0027111
PA0027456
PA0027197
PA0027693
PA0027324
PA0027391
PAG064801
PA0027430
PA0070386
PA0027570
PA0027626
PA0027651
PA0027120
PAG066127
PAG066116
PAG066117
PAG066118
PAG066119
PAG066120
PAG066123
PA0027014
PAG062201
PAG066126
PAG066113
PAG066128
PAG066129
PAG066130
PAG066131
PAG066132
PAG066134
PAG066122
PAG066121
PAG066125
PAG066105
PA0096229
PA0217611
PA0027022
PAG062202
PAG066124
PAG064802
PAG066101
PAG066102
PAG066115
PAG066104
Facility Name
Saltsburg Borough STP
Farrell City
Williamsport Sanitary Authority West Plant
Williamsport Sanitary Authority Central
Lackawanna River Basin Sewer Authority-Archibald
Lackawanna River Basin Sewer Authority-Clinton
Lackawanna River Basin Sewer Authority-Throop
DELCORA Chester STP
New Kensington STP
Greater Greensboro STP
Harrisburg Authority
Minersville Sewer Authority
Shamokin-Coal Township Joint Sewer Authority
Upper Allegheny Joint Sanitary Authority STP
Shamokin City
Jeannette WWTP
Shenandoah STP
Brush Creek STP
Kiski Valley STP
West Newton Borough STP
Warren City
Munhall Boro
West View Borough
City of Uniontown
Borough of Turtle Creek
Borough of Etna
Borough of East Pittsburgh
Borough of West Homestead
Altoona City Authority-East
Easton City
Carnegie Borough
Borough of Aspinwall
Borough of Swissvale
Mayview State Hospital
Export Borough
Freedom Borough
East Rochester Borough
Township of Lett
East Conemaugh Borough
City of Arnold
Sharpsburg Borough
Borough of Rankin
Marianna-West Bethlehem STP
City of Pittsburgh
Altoona West STP
Lackawanna River Basin Authority-Moosic
Dale Borough
Coal Township
Pitcairn Borough
Braddock Borough
Ferndale Borough
Bureau of Wilmerding
Number of I
Outfalls ^^^^1
6
4
1
3
6
9
20
26
5
39
60
7
5
19
33
5
13
3
32
13
4
4
2
28
10
8
3
2
1
2
1
3
1
1
5
3
1
1
2
2
6
2
1
217
1
3
7
33
1
8
5
9
D.5
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
1
1
EPA
Region
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
State
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
NPDES Permit
Number
PAG066114
PAG066106
PAG066107
PAG066108
PAG066109
PAG066110
PAG066111
PAG066112
PA0092355
PAG066103
PA0023701
PA0024490
PA0022306
PA0022331
PA0023175
PA0023248
PA0022209
PA0023558
PA0021814
PA0023736
PA0024163
PA0024341
PA0024406
PA0024449
PA0020125
PA0023469
PA0021237
PA0020397
PA0020613
PA0020681
PA0020702
PA0020940
PA0022292
PA0021148
PA0024511
PA0021407
PA0021521
PA0021539
PA0021571
PA0021610
PA0021687
PA0021113
PA0026492
PA0024481
PA0026204
PA0026301
PA0026310
PA0026352
PA0026182
PA0026476
PA0026174
PA0026557
Facility Name
Borough of North Braddock
Girty's Run JSA, Millvale
Township of Stowe
Township of Wilkins
McDonald Sewage Authority
Borough of Crafton
Emsworth Borough
Borough of McKee Rocks
North Belle Vernon WPCP
Borough of Homestead
Midland Borough Municipal Authority STP
Rockwood Bora STP
Brownsville Municipal Authority-Shady Avenue STP
West Elizabeth WWTP
Kane Borough
Berwick Area Joint Sewer Authority
Bedford Borough Municipal Authority
Ashland Borough
Mansfield WWTP
Tri-Borough Municipal Authority WWTP
Cambria Township Sewer Authority (Revloc STP)
Canton Borough Authority
Mt. Carmel Municipal Authority
Youngwood Borough STP
Boro of Monaca STP
Honesdale STP
Newport Borough Municipal Authority
Bridgeport Borough
Waynesbug STP
Sewickley WWTP
Fayette City WWTP
Tunkhannock Borough Municipal Authority
Ebensburg WWTP
Mt. Pleasant STP
Redbank Valley Municipal Authority
Point Marion WWTP
Smethport Borough
Williamsburg Borough
Marysville Municipal Authority
Blairsville Borough STP
Wellsboro Municipal Authority
Glassport STP
Scranton WWTF
Meyersdale STP
Oil City STP
Erie City STP
Clearfield Municipal Authority
Coraopolis WPCF
Lansdale Borough
Coaldale Landsford-Summitt Hill TP
Franklin City General Authority
Municipal Authority of the City of Sunbury
Number of I
Outfalls ^^^^H
1
9
7
2
20
4
1
3
16
1
1
5
4
1
2
4
2
9
4
2
1
1
19
2
6
9
3
6
2
4
2
1
2
6
1
6
1
1
3
16
2
5
78
5
16
15
9
6
2
6
5
6
D.6
-------
Appendix D
• EPA
Region
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
State
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
VA
VA
VA
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
NPDES Permit
Number
PA0026581
PA0026662
PA0026671
PA0026743
PA0026689
PA0026361
PA0025950
PA0024589
PA0024686
PA0024716
PA0024864
PA0025224
PA0026191
PA0025810
PAG066133
PA0025984
PA0026042
PA0026069
PA0026107
PA0026140
PA0026158
PA0025755
PA0026832
PA0027006
PA0026981
PA0026921
PA0026913
PA0026905
PA0026891
PA0020346
PA0026824
VA0024970
VA0063177
VA0087068
WV0023167
WV0020648
WV0027324
WV0026832
WV0025461
WV0027472
WV0028088
WV0020621
WV0084042
WV0020109
WV0020028
WV0020150
WV0024856
WV0020273
WV0 105279
WV0029289
WV0084310
WV0024848
Facility Name
Scottsdale STP
Philadelphia Water Department-Southeast
Philadelphia Water Department-Southwest
Lancaster City
Philadelphia Water Department-Northeast
Lower Lackawanna Valley Sanitary Authority
City of Monongahela
Leetsdale STP
Mid Mon Valley WPCP
Freeland WWTP
Ligonier Boro STP
St. Clair S.A. WWTP
Huntington Borough
Shade-Central City STP
Rochester Borough
Allegheny County Sanitary Authority
Bethlehem WWTP
Latrobe Borough
Wyoming Valley Sewer Authority
Rochester Area Joint Sewer Authority WTP
Monongahela Valley WWTP
Borough of Freeport STP
Ellwood City Borough
Tamaqua Borough Sewer Authority
City of Duquesne STP
Hazelton WTP
McKeesport WPCP
Connellsville STP
Charleroi STP
Punxsutawney Sewer Authority STP
Clairton STP
Lynchburg STP
Richmond WWTW
Alexandria CSOs
Martinsburg
City of Benwood
Monongah
Wellsburg
City of Bridgeport
New Martinsville
Weston
Montgomery
Flatwoods-Canoe Run PSD
Town of West Union
City of Elkins
Moorefield
Thomas
City of Follansbee
City of Piedmont
City of Belington
Greater Paw Paw Sanitary District
Town of Davis
8
35
83
5
59
26
1
6
8
1
2
7
6
3
5
21
3
18
54
1
21
6
1
13
4
14
28
16
12
4
5
36
29
4
1
14
2
10
12
10
5
5
5
7
19
2
1
5
7
7
7
3
D.7
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
• EPA
Region
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
4
4
4
4
State
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
GA
GA
GA
GA
GA
GA
GA
GA
KY
KY
KY
KY
KY
KY
NPDES Permit
Number
WV0081434
WV0054500
WV0035939
WV0035912
WV0035637
WV0028118
WV0033821
WV01 00901
WV0023175
WV0021865
WV0021857
WV0021822
WV0023094
WV0022080
WV0022063
WV0022039
WV0024732
WV0022004
WV0032336
WV0021881
WV0021750
WV0021741
WV0023124
WV0023299
WV0024589
WV0024562
WV0024473
WV0024449
WV0024392
WV0020681
WV0023302
WV0023159
WV0023264
WV0023230
WV0023205
WV0023183
WV0020141
WV0023353
GA0037109
GA0037168
GA0037133
GA0037117
GA0036871
GA0036854
GA0036838
GA0037125
KY0020095
KY0022373
KY0027413
KY0020257
KY0020711
KY0021440
Facility Name
Town of Barrackville
City of Shinnston
Boone County PSD
City of Kenova
Cedar Grove
Dunbar
City of Logan
Nutter Fort
St. Albans
City of Farmington
City of Philippi
Grafton
Princeton
Town of Bethany
City of Parsons
Point Pleasant
City of Hinton
Richwood
Buckhannon
Kingwood
Marmet
Smithers
City of Morgantown
Nitro
Welch
City of Wayne
Marlington
City of Westover
Keyser
Mullens
City of Clarksburg
Huntington
City of Moundsville
Wheeling
Charleston
Beckley
McMechen
Fairmont
Atlanta-Tanyard Creek
Atlanta-lntrenchment and Custer Avenue
Atlanta-McDaniel Street
Atlanta-Proctor Creek/North
Atlanta-Clear Creek
City of Albany CSOs
Columbus CSO
Atlanta-Proctor Creek/Greenferry
Owensboro-West
Ashland WWTP
Prestonsburg WWTP
Maysville WWTP
Henderson WWTP
Morganfield WWTP
Number of I
Outfalls ^^^^^H
12
10
5
2
1
17
10
2
3
1
13
39
1
3
5
2
6
2
5
3
3
4
40
6
26
3
1
5
1
3
55
25
6
137
55
1
3
43
1
2
1
1
1
8
2
1
8
8
1
11
15
2
D.8
-------
Appendix D
• EPA
Region
4
4
4
4
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
State
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
TN
TN
TN
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
NPDES Permit
Number
KY0021466
KY0021512
KY0026115
KY0026093
KY0022411
KY0035467
KY0025291
KY0024058
KY0022926
KY0022861
KY0022799
TN0020575
TN0020656
TN0024210
IL0029815
ILM580035
IL0022471
IL0028070
ILM580031
ILM580034
ILM580003
ILM580030
IL0066818
IL0068365
ILM580012
IL0070505
IL0021253
ILM580009
ILM580023
IL0072001
IL0030660
IL0034495
IL0033618
ILM580008
IL0033472
IL0031852
IL0031356
IL0045039
IL0030783
IL0037800
IL0030503
IL0030457
IL0030384
IL0030015
IL0029874
IL0029831
IL0031216
ILM580011
ILM580036
IL0045012
ILM580007
ILM580021
Facility Name
Northern Kentucky S.D. #1
Vanceburg WWTP
Loyall WWTP
Harlan WWTP
Morris Forman WWTF
Catlettsburg WWTP
Pikeville WWTP
Pineville STP
Worthington WWTP
E.G. McManis WWTP
Paducah WWTP
Nashville
Clarksville
Chattanooga
City of Mason City
Village of NilesCSOs
Glenbard WW Authority-Lombard
MWRDGC-Lemont WRP
City of Blue Island CSOs
Lincolnwood CSOs
Village of Melrose Park CSO
Village of North Riverside CSOs
Hinsdale CSOs
Marshall STP
Wilmette CSO
City of Elgin CSOs
Monmouth Main WWTP
Village of LaGrange CSOs
Village of Stickney CSOs
Bloomington CSOs
City of Peru STP
Pekin STP 1
Village of Villa Park CSOs
LaGrange Park CSOs
East St. Louis CSOs
Wood River STP
Taylorville S.D. STP
Village of Western Springs CSOs
Rock Island
City of Peoria CSOs
Quincy STP
Pontiac STP
Ottawa STP
Morton STP 2
City of Metropolis STP
Mattoon WWTP
Spring Valley WWTP
Dixmoor CSO
Skokie CSOs
Chicago CSOs
Village of Riverdale CSOs
Village of River Grove CSO
71
5
6
1
115
5
3
3
3
20
11
30
2
9
1
8
2
1
5
2
1
2
4
2
1
12
6
3
1
6
22
4
4
3
2
1
2
4
6
16
6
5
14
2
1
4
9
1
3
231
4
6
D.9
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
• EPA
Region
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
State
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
NPDES Permit
Number
ILM580013
ILM580032
IL0035084
ILM580014
ILM580002
ILM580026
ILM580037
IL0043061
ILM580018
IL0039551
ILM580028
IL0029424
ILM580025
IL0022004
IL0029564
IL0023272
IL0023141
IL0022675
IL0022519
IL0022462
IL0023388
IL0022161
IL0023825
IL0021989
IL0021971
IL0021873
IL0021792
IL0021661
IL0021601
IL0021423
IL0022331
IL0028053
ILM580015
IL0028657
IL0028622
IL0028592
IL0028321
IL0028231
IL0023281
IL0028061
IL0029467
IL0027839
IL0027731
IL0027464
IL0027367
IL0026450
IL0025135
IL0024996
IL0028088
IL0047741
ILM580020
ILM580006
Facility Name
Village of Schiller Park CSO
Brookfield CSOs
City of Casey STP
Park Ridge CSOs
City of Evanston CSOs
Des Plaines CSO
Posen CSO
Prophetstown STP
Village of Burnham CSOs
Village of Lemont CSOs
City of Markham CSO
LaSalle WWTP
City of Calumet City CSOs
City of Streator STP
Lincoln STP
Milford STP
Galesburg Sanitary District
Carlinville STP
City of Joliet-Eastside STP
Farmer City STP
Havana STP
Watseka STP
Cairo STP
Spring Creek STP
Sugar Creek STP
City of Belleville STP #1
Wenona WWTP
Jacksonville STP
Fairbury STP
Village of Hartford CSO
Granville STP
MWRDGC Stickney, West-Southwest STP
Riverside CSOs
Fox River WRD-South STP
Effingham STP
Metro East S.D. CSOs
S.D. of Decatur Main STP
Cowden STP
Gibson City STP
MWRDGC Calumet Water Reclamation Plant
Lawrenceville STP
Canton-West STP
Bloomington/Normal WRD/STP
City of Alton STP
Addison
Dixon STP
Beardstown S.D.
City of Oglesby STP
MWRDGC-Northside Water Reclamation Plant
MWRDGC James C. Kire WRP
City of Harvey CSOs
Village of Arlington Heights CSO
1
6
1
4
15
2
1
2
3
2
1
3
7
17
2
4
40
1
9
2
2
6
3
6
2
15
1
2
11
1
4
15
5
1
3
4
4
1
1
13
4
2
9
6
1
4
1
7
9
1
7
1
D.10
-------
Appendix D
• EPA
Region
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
State
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
NPDES Permit
Number
ILM580016
ILM580004
ILM580019
ILM580005
ILM580029
ILM580022
IL0048518
ILM580033
IL0072389
IL0021113
IL0021059
ILM580024
IL0020621
ILM580017
IL0072834
IL0072508
ILM580010
IL0020818
IN0035696
IN0024520
IN0023183
IN0024473
IN0024414
IN0020044
IN0024406
IN0024023
IN0033073
IN0023914
IN0023752
IN0023736
IN0023621
IN0023604
IN0023582
IN0024554
IN0050903
IN0024805
IN0038318
IN0039314
IN0023302
IN0032719
IN0031950
IN0032191
IN0032328
IN0032336
IN0032468
IN0024775
IN0032573
IN0025674
IN0032875
IN0032956
IN0032964
IN0032972
Facility Name
Village of Calumet Park CSO
Village of Lyons CSOs
Village of Forest Park CSOs
Village of Morton Grove CSOs
Franklin Park CSOs
Village of Maywood CSOs
Aurora CSOs
Summit CSOs
Golf CSOs
City of Morris STP
Marseilles STP
Village of River Forest CSOs
Litchfield STP
Village of Dolton CSOs
Phoenix CSOs
Town of Normal CSOs
Village of South Holland CSOs
Fox Metro Water Reclamation District
Mt. Vernon WWTP
City of South Bend WWTP
Indianapolis-Belmont
City of Seymour WWTP
Rensselaer
City of Alexandria WPCP
Town of Redkey POTW
Paoli Municipal STP
Evansville East WWTP
City of New Castle WWTP
Michigan City
Markle WWTP
Lowell Municipal STP
City of Logansport WWTP
LigonierWWTP
City of Sullivan WWTP
City of Aurora WW Collection System
Warsaw WWTP
Milford
City of Decatur WWTP
Jeffersonville
Elwood
Indianapolis-South Port
City of Fort Wayne WWTP
City of Peru WWTP
Connersville
Lafayette
Wakarusa WWTP
City of Columbus POTW
City of Elkhart WWTP
City of Kokomo Municipal Sanitation Utility
Evansville Westside WWTP
City of Crawfordsville WWTP
Civil Town of Speedway WWTP
1
3
2
2
4
8
16
4
1
5
1
2
1
3
1
0
5
1
3
44
131
1
17
3
6
8
8
8
2
2
1
16
6
5
5
1
1
4
16
15
2
42
16
5
15
7
3
39
30
15
2
2
D.11
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
1
1
EPA
Region
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
State
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
NPDES Permit
Number
IN0023132
IN0023060
IN0032476
IN0025607
IN0024660
IN0024716
IN0024741
IN0024791
IN0024821
IN0025232
IN0025763
IN0025585
IN0025755
IN0025615
IN0025631
IN0025640
IN0025658
IN0025666
IN0024562
IN0025577
IN0020427
IN0020109
IN0020907
IN0020877
IN0020770
IN0020745
IN0020711
IN0020672
IN0020664
IN0020656
IN0020567
IN0020991
IN0020451
IN0021016
IN0020362
IN0020346
IN0020222
IN0020176
IN0020168
IN0020133
IN0020125
IN0020117
IN0020095
IN0020001
IN0022977
IN0020516
IN0021628
IN0022829
IN0022683
IN0022535
IN0022624
IN0022608
Facility Name
City of Huntington WWTP
Hammond WWTP
Anderson WWTP
City of Terre Haute POTW
Elden Kuehl Pollution Control Facility
Veedersburg WWTP
City of Wabash WWTP
Warren
West Lafayette WWTP
Town of Akron WWTP
City of Crownpoint WWTP
City of Marion WWTP
City of Goshen WWTP
William Edwin Ross WWTP
Muncie Sanitary District
City of Mishawaka WWTP
Washington Municipal STP
City of Madison WWTP
Summitville
LaPorte Municipal STP
Bremen WWTP
Greenfield
Rossville
North Judson Municipal STP
Middletown
Ossian WWTP
Waterloo Municipal STP
Auburn WWTP
Avilla WWTP
City of Kendallville WWTP
South Whitley Municipal STP
Plymouth Municipal STP
North Vernon WWTP
Tell City WWTP
North Manchester STP
New Haven STP
Attica
Monticello Municipal STP
City of Noblesville WWTP
Greensburg WWTP
Royal Center WWTP
MontpelierWWTP
Portland Municipal STP
Ridgeville WWTP
Gary WWTP
Winamac Municipal STP
Hartford City
East Chicago S.D.
Town of Crothersville WWTP
Centerville Municipal STP
Columbia City WWTP
City of Clinton POTW
Number of I
Outfalls ^^^^1
15
20
17
10
2
1
8
3
5
3
5
9
6
4
25
19
5
7
2
1
2
0
2
2
3
6
2
4
1
1
2
10
2
5
8
4
2
5
7
1
1
4
16
3
14
5
17
3
2
0
12
6
D.12
-------
Appendix D
1
1
EPA
Region
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
State
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
NPDES Permit
Number
IN0022578
IN0022560
IN0022462
IN0022420
IN0022411
IN0020958
IN0021652
IN0022934
IN0021474
IN0021466
IN0021385
IN0021369
IN0021342
IN0021296
IN0021270
IN0021245
IN0021211
IN0021202
IN0021105
IN0021067
IN0022144
MI0048046
MI0026735
MI0025453
MI0025500
MI0025534
MI0025542
MI0025577
MI0025585
MI0025631
MI0026069
MI0026077
MI0024058
MI0026115
MI0028819
MI0036072
MI0048879
MI0051462
MI0051471
MI0051489
MI0051535
MI0051811
MI0051829
MI0051837
MI0037427
MI0026085
MI0022284
MI0023973
MI0020214
MI0020362
MI0020591
MI0020656
Facility Name
Chesterton Municipal STP
Chesterfield WWTP
Butler
Boonville
City of Bluffton WWTP
Fortville WWTP
Eaton
Frankfort
Tipton Municipal STP
Nappanee
City of Knox WWTP
Berne
Oxford WWTP
City of Angola WWTP
Rushville
Town of Brownsburg WWTP
Brazil Municipal STP
Plainfield Municipal STP
Fairmount
Rockport WWTP
Albion
Bloomfield Village CSO
St. Joseph CSO
Martin RTB
Milk River CSO
Birmingham CSO
Dearborn CSO
Saginaw WWTP
Chapaton RTB
Menominee WWTP
Grand Rapids WWTP
Grosse Pointe Farms CSO
Sault Ste Marie WWTP
Oakland County SOCSDS 12 Towns RTF
River Rouge CSO
Southgate/Wyandotte CSO RTF
Crystal Falls CSO
Wayne County/ Inkster/Dearborn Heights CSO
Wayne County/lnkster CSO
Wayne County/Dearborn Heights CSO
Wayne County/Redford/ Livonia CSO
Dearborn Heights CSO
Redford Township CSO
Inkster/Dearborn Heights CSO
Oakland County-Acacia Park CSO
Grosse Pointe Shores CSO
Bay City WWTP
Saginaw Township WWTP
Norway WWTP
Manistee WWTP
St. Clair WWTP
Marysville WWTP
1
0
1
2
1
7
2
1
7
13
1
3
3
3
2
2
3
5
16
1
2
1
5
2
1
1
19
7
1
1
10
7
6
1
1
2
2
2
10
7
8
1
1
1
1
0
5
0
1
4
0
1
D.13
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
IEPA
Region
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
State
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
MN
MN
MN
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
NPDES Permit
Number
MI0021083
MI0021440
MI0021695
MI0022152
MI0022802
MI0022853
MI0022918
MI0023001
MI0023205
MI0023400
MI0023515
MI0023647
MI0023701
MI0023833
MI0043982
MN0025470
MN0024571
MN0046744
OH0023981
OH0026671
OH0026565
OH0026522
OH0026514
OH0026352
OH0026263
OH0026069
OH0026026
OH0026018
OH0025852
OH0025771
OH0024732
OH0025291
OH0024139
OH0025160
OH0025151
OH0025135
OH0025127
OH0025003
OH0024929
OH0024899
OH0024759
OH0024741
OH0058971
OH0026841
OH0024686
OH0025364
OH0031062
OH0020826
OH01 26268
OH01 05457
OH0094528
OH0020893
Facility Name
Croswell WWTP
Wakefield WWSL
Blissfield WWTP
Adrian WWTP
Detroit WWTP
East Lansing WWTP
Essexville WWTP
Gladwin WWTP
Iron Mountain-Kingsford WWTP
Lansing WWTP
Manistique WWTP
Mt. Clemens WWTP
Miles WWTP
Port Huron WWTP
North Houghton County W&SA CSO
MCWS-St. Paul
Red Wing
MCWS-Minneapolis
City of Avon Lake
Newark WWTP
Village of Mingo Junction
Middletown WWTP
Middleport WWTP
Marion Water Pollution Control
City of McComb WWTP
City of Lima WWTP
Lancaster WWTP
Lakewood WWTP
Ironton WWTP
Hicksville
Columbus-Jackson Pike
Fremont WWTP
City of Bowling Green
Fort Recovery WWTP
Forest WWTP
Findlay Water Pollution Control Center
Fayette WWTP
City of Elyria WWTP
Delphos WWTP
Defiance
Columbus Grove
Columbus-Southerly
Luckey STP
Oak Harbor
City of Clyde WWTP
City of Girard WWTP
Euclid
Village of Leipsic
Lisbon WWTP
Hamilton County Commissioners
Village of Malta
Napoleon WWTP
Number of |
Outfalls
1
1
2
2
86
2
1
1
1
30
1
1
8
14
2
2
1
8
14
25
6
8
13
3
2
19
31
9
9
5
31
13
1
4
3
18
15
27
6
44
4
1
4
9
3
4
18
1
9
213
9
3
|
D.14
-------
Appendix D
• EPA
Region
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
State
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
NPDES Permit
Number
OH0058408
OH0023884
OH0052922
OH0052876
OH0052744
OH0052604
OH0049999
OH0052949
OH0043991
OH0027197
OH0029122
OH0028240
OH0028223
OH0028185
OH0028177
OH0028118
OH0027987
OH0027952
OH0027910
OH0027740
OH0027511
OH0027481
OH0027332
OH0048321
OH0020192
OH0020974
OH0023833
OH0020117
OH0020214
OH0020338
OH0020451
OH0020486
OH0020524
OH0020559
OH0020591
OH0020613
OH0020664
OH0020851
OH0020940
OH0021831
OH0020001
OH0023400
OH0023396
OH0022471
OH0021008
OH0022110
OH0022578
OH0021725
OH0021491
OH0021466
OH0021326
OH0021148
Facility Name
Metamora
Village of Ansonia WWTP
City of Bucyrus
Port Clinton
City of Fostoria
City of Norwalk
Eastern Ohio Regional Wastewater Authority
Tiffin
Northeast Ohio Regional Sewer District
Portsmouth
Village of Gibsonburg
Zanesville WWTP
City of Youngstown WTP
Wooster
Woodsfield WWTP
CityofWillard
Warren
Wapakoneta WWTP
Van Wert
Toledo
Steubenville
Springfield STP
City of Sandusky
Dunkirk
Village of Bradford
Delta WWTP
City of Akron
North Baltimore
Toronto WWTP
Village of Paulding
City of Milford WWTP
Village of Greenwich WWTP
Village of Swanton
Village of Caldwell WWTP
Woodville
Village of New Boston
Crestline WWTP
Bluffton WWTP
Arcanum WWTP
Montpelier WWTP
Upper Sandusky
City of Wauseon
Ohio City
DeshlerWWTP
Perrysburg Water Pollution Control
Newton Falls WWTP
Green Springs WWTP
Pomeroy
Bremen
McConnelsville
Village of Payne WWTP
Village of Pandora WWTP
4
2
22
2
5
3
47
30
126
10
3
21
101
3
5
3
4
4
6
37
16
58
15
6
9
9
38
2
7
2
2
10
13
22
17
2
1
20
14
3
1
4
2
7
4
28
1
13
1
11
2
7
D.15
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Report to Congress on Impacts and Control ofCSOs and SSOs
• EPA
Region
5
5
5
5
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
8
9
9
9
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
State
OH
OH
Wl
Wl
IA
IA
IA
IA
IA
IA
IA
IA
IA
IA
KS
KS
KS
MO
MO
MO
MO
MO
MO
MO
MO
MO
NE
NE
SD
CA
CA
CA
AK
OR
OR
OR
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
NPDES Permit
Number
OH0021105
OH0022322
WI0025593
WI0024767
IA0076601
IA0058611
IA0047961
IA0043079
IA0042609
IA0035947
IA0027219
IA0021059
IA0020842
IA0023434
KS0042722
KS0039128
KS0038563
MO0050580
MO0025178
MO0024929
MO0023027
MO0024911
MO0023221
MO0023043
MO01 17960
MO0025151
NE01 33680
NE0021121
SD0027481
CA0079111
CA0037681
CA0037664
AK0023213
OR0026361
OR0026905
OR0027561
WA0024473
WA0037061
WA0031682
WA0029548
WA0029289
WA0024490
WA0024074
WA0023973
WA0023744
WA0020257
WA0029181
Facility Name
HamlerWWTP
Put-In-Bay WWTP
Superior Sewage Disposal System
Milwaukee MSD-Jones Island
Des Moines CSOs
Ottumwa STP
CityofWapelloSTP
City of Burlington STP
City of Keokuk STP
City of Clinton STP
City of Ft. Madison STP
City of Spencer STP
City of Lake City STP
City of Muscatine STP
Topeka City of Oakland STP
Atchison City WWTP
Kansas City WWTP (and Wyandotte County)
Cape Girardeau WWTP
MSD, Bissell Point WWTP
Kansas City, Westside STP
Sedalia North WWTP
Kansas City, Blue River STP
Macon WWTF
St. Joseph WWTP
Moberly East WWTP
MSD, Lemay WWTP
City of Omaha CSS
Plattsmouth WWTF
City of Lead
Sacramento Regional County S.D.
Oceanside WPCP and Westside Wet Weather CSO System
Bayside WW Facilities WPCP & SF Southeast
Juneau-Douglas WWTP
City of Corvallis WWRP
City of Portland Columbia Blvd WWTP
City of Astoria WWTP
City of Spokane
City of Olympia
City of Seattle
Snohomish WWTP
Bremerton WWTP
City of Everett
City of Mt. Vernon WWTP
City of Port Angeles WWTP
City of Bellingham WWTP
City of Anacortes WWTP
Metropolitan King County - West Point
6
3
3
120
18
10
2
12
9
10
9
4
1
5
6
9
66
0
56
6
1
218
2
15
4
149
31
0
1
6
7
29
3
4
44
38
24
3
113
2
16
14
2
5
2
3
40
D.16
-------
Appendix E
GPRACSO Model Documentation
-------
-------
Appendix E
E.I GPRACSO Database and GPRACSO Model
EPA developed the GPRACSO Database and GPRACSO Model to estimate CSO volume and the attendant
pollutant loads on a national level. The GPRACSO Database contains information for all CSO communities in
the United States. The GPRACSO Model estimates CSO volume and the 6005 load in CSOs for communities
with combined sewer systems (CSSs). This documentation presents background on the sources of information
and the methodology used to develop the GPRACSO Database and Model.
The GPRACSO Database includes information on all of the CSO communities across the United States. The
primary sources of community-specific information include:
EPAs CWNS (1992, 1996, and 2000)
EPAs PCS database
EPAs 2001 Report to Congress- Implementation and Enforcement of the CSO Control Policy
EPA-sponsored municipal interviews with select CSO communities during 2002 and 2003
Individual CSO community long-term control plan documentations
Internet searches
The GPRACSO database contains information on how the CWNS Facility identifying numbers relate to CSO
community names and NPDES numbers, and how complex CSO community systems connect to discharge into
single regional POTWs. For highly detailed assessments of a single CSO community, the GPRACSO database
may not have sufficiently accurate information. However, for EPAs efforts to summarize national conditions, the
combination of the GPRACSO Database and the GPRACSO Model is sufficient for policy, cost, and technology
assessments.
Each CSO community is represented as a specified land area within the GPRACSO Model, and each is associated
with a known quantity of dry weather flow, and a known quantity of wet and dry weather treatment and wet
weather storage. The GPRACSO Model is applied to represent annual average conditions. Typical rainfall years
were developed from long-term meteorologic records for each CSO community. The key inputs to the GPRACSO
model include: service area, population served, impervious cover, rainfall, temperature, treatment plant capacity,
and wet weather storage. A detailed description of each of these parameters, including database sources, is
provided in Table E. 1
A "CSO community" is used herein to generically refer to the entity that terminates at a single POTW. Each
POTW is evaluated as a single entity whether it is an individual sewer system or a totaled regional system.
Wherever multiple CSO communities comprise a single regional system, a single data record, representing
the total treatment capacity, wet-weather storage, and combined sewer service area of all the combined sewer
communities in the regional system, is included in the GPRACSO Database.
The GPRACSO Model was used to estimate CSO volumes and 6005 concentrations for three national planning-
level scenarios: baseline (1992) prior to CSO Control Policy, current level of control, and (future) full CSO
Control Policy implementation. To accomplish this, the GPRACSO Model generates rainfall-derived runoff
from each combined sewer area on an hourly basis, adds the runoff to dry weather flow, calculates the volume of
combined sewage delivered to the POTW, and estimates CSO volume based on storage and treatment capacities.
Hourly estimates of BOD^ concentrations within CSSs are used to calculate the pollutant loads in CSOs and
treated effluent from POTWs. The following sections provide more detail on the GPRACSO model algorithms
and key assumptions.
E-1
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Report to Congress on Impacts and Control ofCSOs and SSOs
Table E.I Summary of Key Inputs to the GPRACSO Model
Combined Sewer System Description Parameters
Service area acreage and
population information
Runoff coefficient
Meteorologic data
Rainfall
Temperature
Estimated CSO service area data for 1992, 1996, and 2000 were obtained from a myriad of sources
including CWNS. Where necessary, either population served or miles of sewer pipe were used to
estimate source area. For a small fraction of the communities, other sources of service area included
direct responses in EPA-sponsored interviews, published reports, and LTCPs.
This coefficient was set to the impervious fraction of each community. Land use/land cover CIS layers
from the USGS (EPA 2001) were used to aerial weight imperviousness based on five urban land use types.
The boundary of each community was identified and was graphically superimposed on the USGS data.
The United States was divided into 84 common hydrologic zones based on average annual precipitation,
mean January air temperature, geography, and peak 2-year, 6-hour rainfall. For modeling purposes,
rainfall is represented in terms of hourly rainfall amounts. It is presumed that all communities located in
common zone would experience the same hydrologic conditions, including snow generation and melt.
(EPA 2001)
Once a "typical" rainfall year was identified for each of the 84 hydrologic zones, the associated hourly
temperature record was taken from National Weather Service records such that snow generation and
melting could be assessed. Estimated (modeled) snow accumulation and snow melt was based on hourly
air temperatures using degree-day methodology (McCuen 1998).
Treatment System/Management System Parameters
Dry weather and
maximum wet weather
POTW flow rates
End-of-pipe wet-weather
treatment capacity
Secondary bypass with
flow recombination
Wet weather storage
capacity
Multiple sources have been reviewed to establish current and historic POTW treatment levels. The bulk
of the information on POTWs originated from EPA's PCS database. For use in the GPRACSO model, the
median value was calculated for both average and maximum design POTW flow based on up to two
years of reported daily average and daily peak discharge rates.
Data was obtained from the internet, published literature, responses in EPA-sponsored interviews, and
LTCPs.
Data was obtained from the internet, published literature, responses in EPA-sponsored interviews, and
LTCPs.
Data was obtained from the internet, published literature, responses in EPA-sponsored interviews, and
LTCPs.
E.2 Simulation of Dry Weather Sanitary Flows
Average daily dry weather sanitary flows for CSO communities are based on discharge monitoring reports
available in PCS. Typical flow peaking factors based on literature values are used to represent the hourly variation
of sanitary flows relative to the average daily flow rate within the CSS and entering the POTW (Metcalf & Eddy
1991). For example, the GPRACSO model sets the minimum and maximum hourly sanitary inflows to 32
percent and 141 percent of the average daily reported POTW inflow. Wherever PCS or other data on both average
and maximum POTW capacity are available for a CSO community, GPRACSO peaking factors are modified
accordingly. Regardless of the conditions encountered, simulated average dry weather sanitary inflow into a
POTW always matches the average inflow obtained from the best available source for each CSO community. The
maximum daily dry weather inflow never exceeds the reported maximum daily POTW treatment capacity.
E.3 Dry Weather Sanitary Pollutant Concentration Estimation
For the purposes of this report, the GPRACSO Model was used to estimate the BOD5 load associated with CSO
discharges. The GPRACSO Model assumes that the average dry weather BOD^ concentration entering the POTW
is 158 mg/L, with minimum and maximum hourly values of 40 and 290 (mg/L), respectively. The average dry
weather concentration and the diurnal (i.e., hourly) variations in pollutant concentration are based on the trend
E-2
-------
Appendix E
reported by Metcalf & Eddy (1991) for the City of Chicago. There were no other influences on hourly dry weather
concentrations unless there were additional inflow from snowmelt or from stored combined sewage returned
from wet weather storage facilities. Algorithms associated with these two inputs are:
Flow source #1: The GPRACSO Model identifies that there is a snow pack present in the CSO community and
that hourly air temperature is above 32 degrees.
Model Response
From the calculated melt rate,an estimate of the snowmelt is made,all of which
is assumed to flow into the CSS. The relative volumes of dry weather sewage and
snowmelt are used to calculate a reduction in the 6005 concentration entering the
POTW.
Assumptions
It is assumed that snowmelt contains
zero pollutant and as a result dilutes the
inflow entering the POTW.
Flow source #2: A CSO community has dedicated wet weather storage available to capture any wet weather flows
in excess of the POTW maximum treatment capacity.
Model Response
The GPRACSO model tracks all of the storage
volume along with the amount of pollutant
(6005) it contains on an hourly basis.
Assumptions
GPRACSO assumes that the stored flow is discharged to the POTW as soon
as there is available treatment capacity (i.e., the hourly POTW inflow is less
than the reported maximum POTW treatment capacity).
E.4 Estimation of CSO Volume
The GPPvACSO Model performs many hydrologic computations as it evaluates the potential and actual wet-
weather inflow into the CSS. The data sources used and the computations performed are as follows.
Typical meteorological conditions were estimated for each CSO community based on a review of long-term data
from the National Weather Service. CSO communities were geographically grouped based on hydrology into 84
common zones, and a typical rainfall year was identified for each zone. As a rule, the typical year contained within
+/-10 percent of the annual average precipitation for that zone or location, and had no single rainfall event larger
than the two-year return period rainfall. Depending on the zone evaluated, the typical rainfall year presents
between 30 and 80 potential overflow-producing events for each CSO community within the zone. Hourly
temperature records was associated with rainfall records for each zone so that snow accumulation and melting
could be included in the GPRACSO Model simulation.
Runoff calculations were performed using the rational method, which multiplies hourly rainfall by a single
coefficient to calculate the runoff. The coefficient was set to equal the overall impervious cover of each CSO
community. As described in Table E. 1 under runoff coefficient, land use/land cover GIS layers from the USGS
were used to help estimate the geographically weighted imperviousness for the land area found within the
political boundaries of the CSO communities.
Snow accumulation and melting were calculated using a degree-day approach applied on an hourly basis
(McCuen 1989). The GPRACSO Model monitors the conditions in each CSO community to determine if snow
pack is present and if it is aggregating or shrinking in any simulated hour. Each hour's temperature was evaluated
to establish the potential snowmelt, and snowmelt was simulated if a snow pack existed.
E-3
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Report to Congress on Impacts and Control ofCSOs and SSOs
POTW wet weather treatment capacity is an important management feature. The GPRACSO model assumes
the average event-period wet weather POTW treatment capacity is 130 percent of the reported maximum daily
treatment rate. Rainfall and CSO events often occur over a period between two and eight hours, a period short
enough for POTWs to "max-out" their systems at a greater rate than possible for a full 24-hour period. For
example, if DMR data for a single POTW indicates 100 MGD is the maximum daily discharge rate (the median of
maximum monthly values reported in PCS), then GPRACSO assumes that the POTW can actually treat 130 MGD
over the short-term (i.e., during wet weather conditions). This 130 percent rule was developed from in-depth
comparison between GPRACSO simulations and the results of local models/studies for four CSO communities.
The GPRACSO simulation assumes the POTW secondary treatment capacity above the simulated hourly dry
weather inflow (the annual average daily POTW inflow multiplied by the appropriate hourly peaking factor) is
available for treating potential CSO. So a POTW with a daily 100 MGD maximum secondary treatment capacity
and an estimated hourly dry weather flow rate of 76 MGD (at 2 pm) would have 54 MGD capacity available
between 2 and 3 pm to manage any wet weather flows (resulting from 100 MGD * 1.3 - 76 MGD). At 3 pm, the
estimated dry weather flow would be about 71 MGD, so any wet weather flows entering the system between 3 and
4 pm would be treated up to 59 MGD (resulting from 100 MGD * 1.3 - 71 MGD).
Wet weather end-of-pipe (EOF) treatment was assumed to occur only after both the maximum wet weather
treatment capacity of the POTW and any wet weather storage is fully utilized during a CSO event. The GPRACSO
Model uses EOF as a last resort treatment, and it cannot be used to drain stored wet weather flows. EOF treatment
technologies considered by the GPRACSO Model include things like vortex treatment facilities.
Wet weather storage was simulated using a built-in algorithm within the GPRACSO Model. The algorithm assesses
the operation of wet weather storage facilities designed to capture and hold wet weather flows until treatment
capacity is available. The operation of wet weather storage is simulated such that any hourly flows in excess of
POTW treatment would go directly to wet weather storage. Only after all available wet weather storage is filled
and EOF treatment capacity is exceeded will GPRACSO simulate a CSO discharge. Available POTW capacity for
draining storage is defined as the difference between the maximum POTW treatment rate and the flow entering
the simulated POTW for any given hour.
Conveyance limits for combined sewer interceptor systems are not considered by the GPRACSO Model. The
GPRACSO Model assumes that the total interceptor system discharging into a POTW has a capacity greater than
the maximum treatment rate of the POTW. As a result, the limiting factor within the GPRACSO Model is the
POTW wet weather treatment capacity. While it is acknowledged that this assumption is not appropriate for some
CSO communities, maximization of flows to the POTW is a required minimum control measure under EPA's CSO
Control Policy.
E.5 Estimation of CSO Pollutant Loads
The GPRACSO Model attempts to recognize the major influences on CSS pollutant concentration on an hour-to-
hour basis. The influences accounted for include:
Flushing of accumulated materials from the CSS
Dilution of sanitary flows by storm water inflow late in the overflow periods
Variation in sanitary flow rate and concentration through the day
The first two influences are lumped into a single load or calculation referred to as "storm water pollutant load".
This load represents the combination of pollutants flushed from pipes and pollutants washed from the urban surface,
E-4
-------
Appendix E
independent of any sanitary inflow rates. In order to estimate the BOD5 loadings attributable to storm water
(including the flushing of settled pollutant in pipes), the following exponential relationship between time and
BOD5 concentration was applied:
Equation 1. C = (200 * 10 -1-5>f(t)) + 15
Where:
C = the BOD^ concentration in mg/L used to calculate the storm water load
t = time in hours since the overflow started
15 = the BOD5 concentration in mg/L assumed to be in urban storm water
Information from two data sources was used to develop the above relationship. The first data source is multi-
event CSO monitoring results of first-flush concentrations in combined sewers for a medium-sized east
coast CSO community. The second data source was from 90*" percentile event mean concentration BOD^
concentrations reported in EPA's Nationwide Urban Runoff Program (EPA 1985). The first data source suggests
that BOD^ concentrations (grab samples in sewers) at the very start of runoff events range between 200 and 400
mg/L, but that concentrations decrease rapidly within the first hour of runoff. As a result, the average first hour
BOD^ concentration is set to be 215 mg/L, using the equation above. The second data source suggests a high-
end long-term urban runoff BOD^ concentration in the absence of CSOs is approximately 15mg/L, a feature also
provided by the equation above.
Calculation of hourly overflow concentration in storm water/sanitary mix. While the first flush effect results in a
high concentration of EOD^, later in the CSO event storm water dilutes the more concentrated sanitary flows. As
a result, the GPRACSO Model continuously mixes the sanitary flow/pollutant load with the storm water runoff/
pollutant load each hour to calculate the average hourly concentration. It is assumed that the mixing of sanitary
and storm water is 100 percent complete for each hour simulated and that any CSOs that occur will contain the
same pollutant concentration as what enters the simulated POTW. The logic used to select the uniform
concentration for any particular hour is:
If EventTime = 0 (the runoff has just started entering the CSS), then
CSCConc(ttt,0) =(200*1CT1-5*leventtime)) + 15
If EventTime > 0 (the overflow event is progressing), then
CSCConc(ttt,0) = (200 * 10 -1 -5*(event time)) + -, 5
If CSCConc(ttt,0) < DWBODconc* hours, then
CSCConc(ttt,0) = (HRDischarge(ttt,0) - HRDWF(ttt,0)) * (CSCConc(ttt,0) +
HRDWF(ttt,0) * DWBODconc * hours) / HRDischarge(ttt,0)
EventTime = time since the start of the overflow event (hours)
CSCConc = uniform concentration of the storm water/sanitary mixture (mg/L) from the combined sewer
community
DWBODconc* hours = the sanitary flow concentration in the absence of overflow (mg/L) for the "hour" under
simulation
HRDischarge(ttt,0) = the simulated total hourly flow in the combined sewer (MGD)
HRDWF(ttt,0) = the hour's sanitary flow rate in the absence of overflow (MGD)
The CSCConc(ttt,0) value is used to compute the CSO BOD5 load, the inflow load entering the POTW, and the
pollutant load stored in any wet weather storage that may be present in the system. For BOD^, the assumed
storm water concentration for the first hour when overflow occurs is 215 mg/L regardless of when it occurs in
the day. For any subsequent hour in which overflow can occur, the BOD5 concentration is the greater of (1) the
E-5
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
value taken from Equation 1 based on the time elapsed since the start of the overflow, or (2) the flow weighted
combination of Equation 1 and the dry weather sanitary flow concentration based on hourly variation. The first
flush is recognized as the strongest influence on concentration at the beginning of the event, the dominant role
of storm water dilution is recognized later in the event, and the daily variation in sanitary flow concentration is
accounted for throughout the event.
E.6 Comparison with Other Estimates
EPA compared GPRACSO results against those of "local CSO models" of varying complexity and sophistication
in five CSO communities. While there is no guarantee that they are correct, the local CSO models were developed
to support LTCPs, and were assumed to be reasonably accurate. EPA used the departure from local CSO model
estimates to gage the relative accuracy of the GPRACSO Model. Based on the local CSO model results, EPA
established the following error brackets for GPRACSO estimates:
CSO volumes are within +/- 50 percent of local CSO model estimates
CSO community-wide average annual pollutant EMCs are at +/- 80 percent of local CSO model estimates
CSO pollutant loads are within +/- 80 percent of local model estimates
Overall, errors originate from two principal sources: inaccuracies in data describing CSO communities, and
errors resulting from the GPRACSO Model algorithms. EPA believes that the larger error is associated with the
first source; that the bulk of the model error originates from errors in the basic system data (e.g., the combined
sewer service area in each CSS). For several years, EPA has collected data to improve its understanding of historic,
current, and future conditions in communities with combined sewers, obtaining better data each year. Additional
investigation of CSO communities is anticipated to improve the assessment with the GPRACSO Model and its
associated database.
To date, an in-depth comparison of local models and GPRACSO algorithms has not been performed. For the
GPRACSO Model, extensive efforts were made to account for the majority of physical and hydrologic factors
encountered in the generation of sanitary and storm water flows. Reasonable data sources are used to estimate the
performance of POTWs and the operation of wet weather treatment and storage. However, the GPRACSO Model
greatly simplifies the influence of geographic dissimilarities to each city, e.g., network of sewer pipes and pump
stations are not explicitly modeled.
E.7 Summary
The GPRACSO Database and application of the GPRACSO Model have been applied to estimate the CSO
volume and annual BOD^ load for all combined sewer communities nationwide. The GPRACSO Model has
been applied to estimate the current annual performance expected under rainfall that are both local to each
community and typical on an annual basis. In addition, GPRACSO model results are conditions based on historic
POTW performance data. Recent POTW upgrades and/or new wet weather management facilities may not be
incorporated within the current version of the GPRACSO database. (Note: EPA is continuously collecting data on
CSS facilities that can be used to update the GPRACSO database). For this reason, the estimates produced by the
GPRACSO simulation may not fully recognize current management.
For its analysis of CSO regulations, EPA has used the typical or average meteorologic conditions faced by each
community to analyze annual CSO management performance, and then summed all communities to obtain
a national total performance. The GPRACSO Model estimates of the typical performance will vary from the
actual performance measured at a specific place and time, in a single community. This is because the actual
E-6
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Appendix E
meteorologic conditions (e.g., the weather at 12 PM on May 1, 2002) will vary from that found in the matching
hours meteorologic record for the selected typical year.
References
EPA. 1983. Results of the Nationwide Runoff Program, Vol 1, Final Report. NTIS PB84-185552.
EPA. Office of Science and Technology. 2001. Better Assessment Science Integrating Point and Nonpoint Sources:
BASINS Version 3.0, User's Manual. EPA 823-B-01-001.
McCuen, R.H. 1989. Hydrologic Analysis and Design, 2nd edition. Prentice-Hall. Upper Saddle River, NJ.
Metcalf & Eddy. 1991. Wastewater Enginnering Treatment, Disposal, Reuse, 3rd edition. McGraw Hill International.
Water Environment Federation (WEF) and American Society of Civil Engineers (ASCE). 1998. Urban Runoff
Quality Management. WEF Manual of Practice No. 23. ASCE Manual and Report on Engineering Practice No. 87.
Reston,VA:ASCE.
E-7
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Appendix F
Analysis of CSO Receiving Waters
Using the National Hydrography
Dataset(NHD)
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Appendix F
F.I Background
EPA compiled a national inventory of NPDES permits for CSO facilities during the development of the Report
to Congress-Implementation and Enforcement of the Combined Sewer Overflow Control Policy (EPA 2001). Data
collection, management, and analysis are documented in Appendix F of the 2001 report. The national CSO
inventory was developed from a review of permit files and information provided by NPDES authorities. The
resulting inventory included a summary of total CSO outfalls per permit and, where available, a narrative
descriptions of CSO outfall location (e.g., "near intersection of Water and Main Streets") and/or by spatial
coordinates (i.e., latitude and longitude). This inventory was reviewed by states and EPA regions to determine if
the total number CSO outfalls was correct, but the information on outfall location was not verified as part of the
2001 report effort.
F.2 Objectives
As specified in the Consolidated Appropriations Act for Fiscal Year 2001 (PL. 106-554):
..the Environmental Protection Agency shall transmit to Congress a report summarizing—
(1) the extent of the human health and environmental impacts caused by municipal combined sewer
overflows and sanitary sewer overflows, including the location of discharges causing such impacts, the
volume of pollutants discharged, and the constituents discharged;...
Given this requirement, and with the CSO permit inventory in-place from the 2001 report, EPA established a
goal of updating the CSO data to include geographical locations for CSO outfalls included in CSO permits. EPAs
overriding objective for this effort was to provide a framework for identifying areas at and downstream of CSO
outfalls to examine potential environmental and human health impacts.
F.3 Development of a National CSO Outfalls GIS Database
EPA began the process of geographically locating CSO outfalls by building on data originally collected for the
2001 report. The CSO permit inventory was updated through a review by states and EPA regions. Based on
the latest data updates, EPA obtained latitude and longitude for outfalls included in more than two-thirds of
active CSO permits. Most of the other permits had narrative descriptions locating CSO outfalls. These narrative
descriptions varied, but generally mentioned the nearest cross-street or public landmark and often included the
name or description of the receiving waterbody.
EPA extracted CSO outfalls with narrative location descriptions. EPA utilized ESRI ArcGIS for the geo-spatial
processing and analysis of these outfalls. EPA developed a GIS base map of land areas, transportation networks,
and local waterbodies for each CSO permit to help locate outfalls based on narrative data. The analysis utilized
the Census 2000 Topologically Integrated Geographic Encoding and Referencing (TIGER®) database of the U.S.
Census Bureau for reference mapping. The geographic data for the TIGER® database is freely available from ESRI
in ArcGIS format. The TIGER® database includes geographic data for roads, railroads, hydrography, utility lines,
and government entities (e.g., places and counties).
EPA extracted TIGER® base map data for over 200 areas to match the more than 2,000 narrative outfall locations
to a spaital location. A combination of ArcGIS address mapping (where street data were available) and visual
identification were employed to match the narrative location to a geographic point. Once located, additional
descriptive information was used to verify the position. This included comparing the ArcGIS mapped position
relative to receiving waters or distance from landmarks recorded in the CSO inventory. Narrative locations
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Report to Congress on Impacts and Control ofCSOs and SSOs
not identifiable within the ArcGIS analysis were excluded, and points that could not be confirmed with other
narrative descriptive locators were flagged for follow-up with the NPDES authority and were updated as
necessary. Upon completion of identification and updates, the spatially-referenced CSO outfall latitude and
longitude coordinates were computed and exported.
With this procedure, over 90 percent of CSO outfalls were geographically mapped. These outfalls were then tested
for data quality and consistency. The CSO outfalls were intersected with available GIS data (states, watersheds,
and waterbodies). CSO permits were linked to PCS to supplement data for descriptive outfall locations within the
CSO inventory. Spatially-referenced CSO outfalls with state, watershed 8-digit HUC, or waterbody information
from PCS inconsistent with that obtained from the ArcGIS base data were flagged for review by the NPDES
authority. Upon completion of review and incorporation of available updates, the CSO outfalls associated with
nearly 95 percent of active CSO permits were geographically referenced, as shown in Figure E1. The spatially-
referenced CSO outfalls served as a data source for evaluating and assessing potential environmental and human
health impacts from CSO discharges.
F.4
Available EPA Data Sources
EPA conducted literature reviews and developed an inventory of possible data sources at the federal, state, and
local levels that could be used to assess potential impacts from CSOs. The listing below reflects national scale
data sources used to assess potential impacts from CSOs. These descriptions include website citations where the
data source is described in more detail, including references to data dictionaries and/or other metadata, analyses
conducted, and findings. The application of these data sources for this Report to Congress is presented in the next
section.
Figure F.I Location of CSO Outfalls
.O
F-2
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Appendix F
Permit Compliance System (PCS) - http://www.epa.gov/enviro/html/pcs/
Discharge of pollutants into waters of the United States is regulated under the NPDES program, a mandated
provision of the Clean Water Act. To assist with the regulation process, state and federal regulators use an
information management system known as PCS. PCS stores data about NPDES facilities, permits, compliance
status, and enforcement activities for up to six years. PCS includes data on CSO permits but lacks data on location
of outfalls for most permits. EPA is currently working with the regions and states to develop an approach for
including and maintaining CSO outfall locations within the existing PCS framework. While PCS is a tool for EPA
and state use only, public data are made available through EPAs Envirofacts website http://www.epa.gov/enviro/,
which provides a single point for accessing EPAs facility dataset.
National Assessment Database (NADB) - http://www.epa.gov/305b/2000report/
The National Assessment Database contains information on the attainment of water quality standards.
Assessed waters are classified as "fully supporting," "threatened," or "not supporting," their designated uses. This
information is reported in the NWQI Report to Congress under Section 305(b) of the Clean Water Act. Analyses
presented in this report use EPAs 2000 NWQI Report to Congress and the NHD-referenced data as means of
assessing areas downstream of CSO outfalls.
Water Quality Standards Database (WQSDB) - http://www. epa.gov/wqsdatabase/
The WQSDB contains information on the designated uses for waterbodies. Designated uses set a regulatory goal
for the waterbody, define the level of protection assigned to it, and establish scientific criteria to support that
use. While not directly used for this report, the WQSDB provides supporting reference and data for EPAs 305(b)
NWQI.
303 (d) Total Maximum Daily Load (TMDL) Tracking System - http://www.epa.gov/tmdl/
The TMDL Tracking System contains information on waters that are not supporting their designated uses. These
waters are listed by the state as impaired under Section 303 (d) of the Clean Water Act. The status of TMDLs is
also tracked. This report uses the April 1,2002 NHD-referenced data to consider 303(d) listed waters downstream
of CSO outfalls and to examine TMDLs in place for those areas.
Safe Drinking Water Information System (SDWIS)
The Safe Drinking Water Act requires that states report information to EPA about public water systems,
including violations of EPAs drinking water regulations. The Safe Drinking Waters Act regulations and their
enabling statutes establish maximum contaminant levels, compliance guidelines, and monitoring and reporting
requirements to ensure that water provided to customers is safe for human consumption. This information is
stored in SDWIS. Data as of June 25, 2003, was provided by EPAs Office of Ground Water and Drinking Water in
an NHD-referenced format to facilitate comparison with known CSO outfall locations.
National Shellfish Register of Classified Growing Waters
The classification of shellfish-growing waters is based on the National Shellfish Sanitation Program (NSSP),
a cooperative effort involving states, the shellfish industry, and the FDA. Since 1983, it has been administered
through the Interstate Shellfish Sanitation Conference (ISSC). The ISSC was formed to promote shellfish
sanitation, adopt uniform procedures, and develop comprehensive guidelines to regulate the harvesting,
processing, and shipment of shellfish. In 1995, the NSSP and coastal states listed over 33,000 square miles of
marine and estuarine waters as classified shellfish-growth areas and published the coverage for distribution in
ArcGIS geographically referenced areas. The areas are very site-specific and not a part of a hydrography network.
Nonetheless, the data were easily linked to nearby CSO outfalls via standard ArcGIS geoanalysis detailed later in
this appendix.
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Report to Congress on Impacts and Control ofCSOs and SSOs
F.5 Technical Approach
The technical approach taken to link a digital CSO outfall dataset to other EPA data and program assessments is
summarized below. The key activities undertaken for this effort include converting CSO outfall data to a spatially
referenced digital format, relating the outfall locations to the NHD, and using the NHD stream network to look
at areas at and downstream of the CSO outfalls through comparative analysis of other EPA data referenced to
the NHD. EPA maintains program data including 303(d) lists, 305(b) assessments, and drinking water intake
data linked to the NHD in its Reach Address Database (RAD). RAD provides the linkage from EPA datasets to
the NHD referenced water reaches. EPAs Watershed Assessment, Tracking, & Environmental Results (WATERS)
initiative serves as a common platform for linking data from all of EPAs surface water programs. These
relationships are discussed in more detail below.
National Hydrography Database (NHD) - http://nhd. usgs.gov/
NHD is a nationally consistent hydrography dataset for the United States. A culmination of recent cooperative
efforts between EPA and USGS, it combines elements of USGS digital line graph hydrography files and the EPA
Reach File (RF3). NHD is designed to serve three simultaneous functions for surface waters:
1. Provide a standard unique identifier (reach code) for each part of the surface water network.
Reach codes act like street addresses in a road network, providing a unique identifier for streams
and other waterbodies.
2. Contain a tabular routing (navigation) network of these features.
3. Include a digital map representation of these features.
The analyses conducted for this report use the three functions of NHD. With NHD, CSO outfall locations are
described by reach, the network is used to examine downstream conditions, and a visual representation of the
locations and downstream pathway is given.
NHD is currently available in 1:100,000 (1:100K) scale format from USGS for the continental United States.
Although some states are moving to higher resolution representations of their waters (e.g., the 1:24,000 (1:24K)
scale), the 1:100,000 scale NHD was used for the analyses presented in this report.
Reach Address Database (RAD) - http://www. epa.gov/waters/about/rad. html
EPAs RAD stores program data linked to NHD reaches, including information on the spatial extent of various
program data. Datasets in RAD include, but are not limited to, the 303(d) and 305(b) programs. RAD stores only
locational information for stream addresses (i.e., position of the listing within the NHD reach network). The
details of that reach, such as designated use, monitoring results, assessment scores, or impairment type, remain
in the program database. This report uses RAD as the gateway for linking CSO outfalls referenced to NHD with
other EPA program data.
Reach Index and Reach Navigation of the Digital CSO Outfalls
A Reach Indexing Tool (RIT) was used to designate CSO outfall locations to the nearest point of an NHD reach,
creating a CSO outfall stream address. These data were transferred to the RAD to provide instant linkage to other
RAD program data. In order to access the other data, the CSO outfall addresses were then 'reach walked' to other
RAD data. The reach walk is a service available within the WATERS system that allows upstream or downstream
navigation of the NHD network, and thus a traverse of any data in the RAD/WATERS system. The reach walk
was conducted to provide information on the distance between the CSO outfall stream address and other EPA
F-4
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Appendix F
program data within RAD.
Downstream Analysis, Impacts, and Pollutants of Concern
For analysis of the reach walked NHD data, a downstream distance of one mile was considered to be a point
where CSO impacts would be most discernable. Where pollutant or stressor information was available, the
primary pollutants found in CSOs (pathogens, solids (TSS), and oxygen-demanding organic materials measured
as BOD^) were included in the analysis.
F.6 Analysis and Results
305(b) Analysis and 303(d) Analysis
Electronic data were available via WATERS within the RAD framework for 305(b) (assessment) and 303(d)
(listing) information, as part of the Clean Water Act requirements. While 303 (d) listed waters were available
electronically for all states except Alaska, electronic 305(b) assessments were available for 13 of the 32 CSO states
(as shown in Figure F.2). Data comparisons were made only for states where data were available.
State assessed waters within one mile downstream of CSO outfalls were evaluated. Waters in that distance with
a cited impairment (pathogens, sediment/siltation, and organic enrichment causing low dissolved oxygen) were
further examined. For example, existing TMDLs were reviewed to explore the relationship between impairment
and source load allocation, including CSOs, as part of the existing TMDL. The tables on the next page summarize
the findings.
Figure F.2 CSO States with Electronic NHD-lndexed 305(b) Assessed Waters
CSO States
CSO States w/electronic 305(b) data
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Report to Congress on Impacts and Control ofCSOs and SSOs
Table F.2 Waters Considered in this Analysis
In CSO States
# of NHD Reaches
1,495,853
within 1 mile downstream of a CSO Outfall
1,560
Table F.3 2000 NWQI Assessment within 1 mile of CSO Outfall
Assessed Waters
Total Assessed as Assessed as Percent
Assessed Good Impaired Impaired
Assessed 305(b) segments in CSO _- ,,_
states with electronic 305(b) data
44,457
14,878 25%
Assessed segments within one mile
downstream of a CSO outfall
733
181
552
75%
Table F.4 303(d) Listed Waters by Cause Categories aligning with impacts from CSOs
Reason or Cause of Listing
Listed Waters
Pathogens Enrichment Leading Sediment
to Low Dissolved and
Oxygen Siltation
Total number of listed waters in CSO
states
Number of listed waters within one
mile of a CSO outfall
3,446
191
1,892
163
3,136
149
Drinking Water Analysis
The SDWIS database and the CSO database were geospatially cross-referenced using the NHD. The location of
drinking water intakes downstream of a CSO was determined and their proximity was assessed.
The database was queried selecting the drinking water intakes within one mile of a CSO outfall. Phone interviews
were conducted with both the NPDES and drinking water authorities for cities with CSOs located within one mile
upstream of a drinking water intake to confirm the location of the CSO outfall, whether the CSOs are active, and
the location of the drinking water intake. Two facilities were eliminated from the analysis because their drinking
water intake or their CSO outfalls were not located within the one-mile analysis radius. The results of this analysis
are summarized in Table E5.
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Appendix F
Table F.5 Association of CSO Outfalls with Drinking Water Intakes
EPA Region
CSO Outfalls within 1 Mile Upstream
of a Drinking Water Intake
Total:
59
Note: EPA was unable to confirm data for an additional 14 outfalls in two states (PA and WV);
these outfalls are not included in this table.
Classified Shellfish-Growing Areas Analysis
Classified shellfish-growing areas are not georeferenced to the NHD. The geographic coverage available from NOAA
provides spatial locations of the shellfish-growing areas and associated attribute data. The attribute data include
information such as the shellfish classification and suspected sources of pollution including wastewater treatment
plants and CSOs.
Given the geospatial location of the CSOs and shellfish-growing areas, it is possible to analyze the distance between
the two datasets using a buffer. A buffer creates an area around a geospatial dataset for a specified distance. It is
then possible to intersect the buffer with another dataset to determine if they coincide spatially. This buffer process
was used to determine how many CSOs are located within five miles of a shellfish-growing area. The results of this
analysis are summarized in Table E6 below.
Table F.6 Classified Shellfish-Growing Areas Within Five Miles of a CSO Outfall
Shellfish Harvest Classification
Prohibited
Restricted
Approved
Unclassified
Total
Number of Classified Shellfish Growing Areas
within 5 Miles of a CSO outfall
659
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Appendix G
National Estimate of SSO
Frequency and Volume
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Appendix G
G.I Summary
National estimates of SSO frequency and volume were generated based on reporting data for more than 33,000
SSO events provided by 25 states during calendar years 2001, 2002, and 2003. The discussion of SSOs in this
report does not account for discharges from points after the headworks of the treatment plant, regardless of
the level of treatment, or backups into buildings caused by problems in the publicly-owned portion of the
SSS. Therefore, these estimates of SSO volume and frequency do not account for discharges occurring after the
headworks of the treatment plant or backups into buildings. Estimates were generated by extrapolating these
data across the remaining 25 states and Washington, D.C., through a five-step procedure:
1. Tabulate the total number of SSO events and the SSO volume for each of the reporting states.
2. Estimate the total number of SSO events per year for each non-reporting state based on the number
of sewer systems in the state or the population served by sewer systems in the state.
3. Divide the total number of events in each non-reporting state into different categories describing
the cause of the SSO event based on observed regional differences among the 25 reporting states.
4. Calculate the SSO volume for each cause category in each non-reporting state to account for
observed regional differences.
5. Calculate national estimates by summing the total number of events by state and the total volume
across all states.
A range of estimates corresponding to different assumptions regarding the nature of the reported data was
generated. Results of the analysis indicate that the annual frequency of SSO events is between 23,000 and
75,000 events per year, with a corresponding volume of 3 to 10 billion gallons per year. This relatively large
range is due to uncertainty regarding the extent to which the reported SSO events reflect all SSO events that
occurred during calendar years 2001, 2002, and 2003.
This appendix summarizes how the estimates of SSO frequency and volume were generated. The discussion is
grouped into the following sections:
Data available • Assumptions • Results
Inital data assessment • Calculation procedure
G.2 Data Available
The national estimates of SSO frequency and volume were based on data provided by 25 states over three years
(January 1, 2001 to December 31, 2003). Data were provided by:
California • Maryland • Rhode Island
Colorado • Massachusetts • South Carolina
Connecticut • Michigan • South Dakota
Florida • Minnesota • Utah
Georgia • New Hampshire • Washington
Hawaii • Nevada • Wisconin
Indiana • North Carolina • Wyoming
Kansas • North Dakota
Maine • Oklahoma
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Report to Congress on Impacts and Control ofCSOs and SSOs
These data were obtained directly from the NPDES authority in each of these states. Data were typically compiled
in either a database or spreadsheet. Specific data elements tracked by NPDES authorities are summarized in Table
G.I.
Table G.I Data Elements Tracked by NPDES Authorities with Electronic Systems
Date & Start Date End Date
Time &Time &Time/
Total
Overflow
Volume
(gallons)
SSO Cause Response Receiving
sures Water
Identified
a May not include exact SSO location point
b May include cleanup activities, volume recovered,and corrective or preventive measures
A total of 36,325 SSO event records were collected from the NPDES authorities and compiled into a single data
management system. No attempt was made to verify the quality or accuracy of the data with the individual
jurisdictions reporting the SSOs; however, a quality check of the data was performed to identify discrepancies
(e.g., gallons versus million gallons, dates outside of the 2001-2003 range, and records with no dates). Reported
events with missing event volumes were used to generate frequency estimates, but were not used for volume
G-2
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Appendix G
estimates. Reported events with dates outside of the 2001-2003 range and events with no dates were not used
to estimate SSO frequency or volume. After the screening, a total of 33,213 records remained describing event
frequency, and 28,708 records remained describing event volumes.
Some states did not provide data for the entire three-year period. SSO frequency data for these states were
adjusted proportionally to account for the missing months. For example, the number of observed events for a
state providing 21 months of reports out of the 36-month period were scaled up by a factor of 36/21.
Basic information describing the sewered universe in each state was obtained from the 2000 CWNS and
included:
Total number of collection systems by state
Number of SSSs by state
Population served by SSSs by state
Lastly, data for each state were grouped by EPA Region to facilitate analysis of regional differences. The number
of SSSs and the population served are presented by Region in Table G.2.
Table G.2 Number of SSSs and the Population Served by the SSSs for each Region
•T.A r, • -r * i i. i <•<•.- Population served by SSSs
EPA Region Total number of SSSs K , '
(in millions)
1
2
3
4
5
6
7
8
9
10
705
1,518
2,149
2,678
4,296
2,983
2,619
1,437
1,003
823
6.18
14.51
15.49
29.89
27.05
25.67
7.58
7.78
33.38
6.36
G.3 Initial Data Assessment
Several analyses were conducted to assess the data prior to estimating SSO frequency and volume. The initial
data assessment included:
Analysis of climatic conditions
Analysis of the variability of discharge volume, number of systems reporting at least one event,
population served, and SSO event frequency
Regional characterization of frequency, volume, and cause category
Analysis of volume discharged by cause category
Statistical regressions to predict frequency of events for non-reporting states
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Report to Congress on Impacts and Control ofCSOs and SSOs
These analyses are discussed in more detail below.
Analysis of Climatic Conditions
Annual precipitation statistics developed by the National Climatic Data Center (NCDC) suggest that no obvious
bias towards wet or dry conditions was observed. Climatic conditions in the reporting states over the three-year
period ranged from record drought to record rainfall. The results of NCDC's analysis for 2001-2003 are presented
in Table G.3 for the 24 of the reporting states. Data for Hawaii were not available.
Table G.3 National Precipitation Summary by State for 2001-2003
State 2001 2002 2003
CA
CO
CT
FL
GA
IN
KS
MA
MD
ME
Ml
MN
NC
ND
NH
NV
OK
Rl
SC
SD
UT
WA
Wl
WY
Near normal
Near normal
Below normal
Near normal
Below normal
Above normal
Near normal
Near normal
Much below normal
Record driest
Much above normal
Above normal
Much below normal
Near normal
Much below normal
Near normal
Near normal
Near normal
Much below normal
Above normal
Near normal
Near normal
Above normal
Below normal
Below normal
Record driest
Near normal
Above normal
Near normal
Above normal
Below normal
Near normal
Near normal
Near normal
Near normal
Above normal
Near normal
Below normal
Near normal
Much below normal
Near normal
Near normal
Near normal
Below normal
Much below normal
Below normal
Above normal
Much below normal
Near normal
Below normal
Much above normal
Above normal
Above normal
Above normal
Near normal
Much above normal
Record wettest
Near normal
Near normal
Below normal
Record wettest
Below normal
Above normal
Near normal
Below normal
Above normal
Above normal
Near normal
Near normal
Near normal
Below normal
Below normal
Analysis of Variability
The first data assessment step was to statistically characterize the variability in the parameters used to generate
the national estimates. The first parameter evaluated was SSO event discharge volume. A frequency distribution
was generated for the reported volume data and goodness-of-fit tests were conducted to determine the type of
statistical distribution that the data exhibited. The volume distribution was reasonably described with log-normal
distributions.
Three additional parameters related to event frequency were investigated, and each was characterized with a
single value for each state. The parameters were: 1) number of systems with events; 2) population served; and 3)
number of events per year. Frequency distributions were generated for each of these parameters and goodness-of-
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Appendix G
fit tests were conducted to determine the type of statistical distribution. Log-normal distributions were found to
adequately describe each parameter.
Regional Characterization
The data for SSO frequency, volume, and cause were stratified by EPA region to determine if geographical
differences in SSO characteristics existed. The cause of SSO events was found to vary significantly by region.
Box and whisker plots were initially generated to provide a visual depiction of differences in volume by region.
Analysis of variance (ANOVA) testing was then conducted to verify that significant differences existed between
regions. Once these differences were confirmed, additional Bonferroni-adjusted ANOVA testing was conducted
to identify individual differences between regions. Analyses were conducted on log-transformed data, consistent
with the determination of log-normality discussed earlier. Based on these results, all subsequent analyses for
cause category were conducted on a region-specific basis. State-specific cause information was used for the 25
states in EPAs data management system. Distributions for SSO cause were developed and applied by region to
states without state-specific information in EPA Regions 1, 3,4, 5, 9, and 10. One average cause distribution was
used for Regions 6, 7, and 8 because the cause of SSO events reported by the states in these regions was very
similar. Finally, none of the 25 states in EPAs data management system are in EPA Region 2, so an average cause
distribution was developed and applied from the reporting states in Regions 1, 3 and 5. The cause distributions,
by region, for non-reporting states are summarized in Table G.4.
Table G.4 Percentage of SSO Events, by Cause, by Region
„ . „. . . ,... Mechanical/Power ,., ... . ... ...
Region Blockage Line Break/Misc. .. Wet Weather - I/I Unknown
1
2
3
4
5
6
7
8
9
10
41%
25%
36%
34%
8%
48%
48%
48%
69%
22%
13%
12%
13%
11%
10%
9%
9%
9%
15%
13%
10%
11%
7%
7%
16%
7%
7%
7%
6%
16%
30%
36%
13%
12%
58%
21%
21%
21%
1%
6%
6%
17%
30%
35%
8%
15%
15%
15%
9%
43%
Less significant regional differences were observed for SSO event frequencies and the volume of individual spills;
therefore, subsequent analyses regarding SSO event frequencies and volumes were not stratified on a regional
basis.
Analysis of Volume Discharged by Cause Category
The next data assessment step was to determine whether a relationship existed between volume discharged
and cause of the SSO event. SSO volumes were found to vary significantly across most cause categories. Box-
and-whisker plots were generated to provide a visual depiction of differences in volume by cause category.
No significant differences in volume discharged were observed across the cause categories of Line Break and
Miscellaneous. These two categories were therefore combined into a single category, as shown in Table G.4.
ANOVA testing was conducted to verify that significant differences existed between the remaining categories.
Once these differences were confirmed, additional Bonferroni-adjusted ANOVA testing was conducted to identify
G-5
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Report to Congress on Impacts and Control ofCSOs and SSOs
individual differences between cause categories. Analyses were conducted on log-transformed data, consistent with
the determination of log-normality discussed earlier.
Statistical Regression to Estimate SSO Frequency
In order to estimate national SSO frequency, the frequency data from the reporting states were extrapolated to
estimate the non-reporting states. For this final data assessment step, a series of linear regressions were developed
allowing event frequencies to be estimated for each state. Several regressions (both in linear and log-log space) were
conducted to evaluate potential predictors of event frequency. The independent variables evaluated were:
Number of SSSs in the state reporting at least one SSO event
Total number of SSSs in the state
Population served by SSSs in the state
Based upon these analyses, the two best predictors of event frequency were:
1) Log-log regression of number of SSO events per year as a function of the number of SSSs in the state with
events, linked to a second regression of number of SSSs in the state reporting at least one SSO event with
events, as a function of total number of SSSs in the state; and
2) Log-log regression of number of events per year as a function of total population.
Both methods provided a similar level of accuracy, explaining approximately 40 percent of the variability in the
observed frequency data; therefore, both the system-based and population-based methods were used in generating
the national estimates.
G.4 Assumptions
Estimating the national SSO frequency and volume from available data required a number of assumptions. The two
primary assumptions that have the greatest potential to affect the estimates are:
The degree to which reported SSO events in a specific time period represent all SSO events that occurred
statewide during the same period; and
The degree to which the number of SSSs in a state serves as a predictor of SSO frequency and volume,
compared to population served.
To account for the uncertainty caused by these assumptions, separate analyses were conducted using a range of
values. The range of results obtained from these alternative analyses helps to bound the uncertainty in the estimates
generated.
Scenarios Evaluated
Different assumptions can be made regarding the degree to which the reported data represent statewide conditions.
It could be assumed that each state's reporting data reflect all SSO events that occurred in that state. Alternatively,
it could be assumed that the data reflect SSO events that occurred only for those communities that chose to
report SSO events. It is not clear at this time which of these assumptions is most appropriate. To account for the
uncertainty caused by these alternate assumptions, two separate scenarios were simulated:
Scenario 1: Available reporting data reflect all SSO events that occured statewide
Scenario 2: Available reporting data reflect events that occured for only those communities that chose to
report
G-6
-------
Appendix G
These scenarios were further evaluated using two different predictors of SSO frequency for states that do not
track SSOs electronically:
Predictor a: Event frequency based on total number of separate sewer systems in state
Predictor b: Event frequency based on population served by separate sewers in state
The two pairs of assumptions discussed above result in four possible combinations of scenarios: la, Ib, 2a, and
2b. Scenario 2b, however, could not be evaluated as it requires data on population served by separate sewers in
each municipal jurisdiction reporting at least one SSO event. These data were available only on a statewide basis.
Consequently, only three scenarios were evaluated: la, Ib, and 2a.
G.5 Calculation Procedure
National estimates of SSO frequency and volume were generated by extrapolating the available data across the
remaining 25 states (and Washington, D.C.) through the following five-step procedure:
1. Tabulate the total number of SSO events and the SSO volume for each of the reporting states.
2. Estimate the total number of SSO events per year for each non-reporting state.
3. Divide the total number of SSO events in each non-reporting state into different categories describing
the cause of the SSO event.
4. Calculate the SSO volume for each cause category in each non-reporting state.
5. Calculate national estimates by summing across all states.
Step 1. Data Tabulation
Data tabulation was described earlier.
Step 2. Estimate total number of SSO events per year for each state
The total number of SSO events per state was calculated for all three scenarios. Scenarios la and Ib assume
that the available reporting data reflect all SSO events statewide, so the reported frequencies were not adjusted
when calculating frequencies for the non-reporting states. Scenario 2a assumed that the available reporting data
reflect only those communities that choose to report. For Scenario 2a estimates, the expected frequencies were
scaled upward to represent the ratio of separate sewer systems reporting SSO events to the total number of sewer
systems. Non-reporting communities in each state were assumed to experience SSOs in a frequency distribution
that matched the reporting communities.
Step 3. Divide total number of SSO events into respective cause categories
The initial data assessment calculated the relative frequency of the cause of SSO events by EPA region. Region-
specific ratios are applied in Step 3 to define the number of events by cause category for each non-reporting state,
as presented in Table G.4.
Step 4. Calculate SSO volume for each cause category
The initial data assessment defined SSO event volume as a function of cause. These region-specific cause and
cause-specific volumes were applied in Step 4 to the frequency of events to define the total volume of SSO by
cause category for each of the non-reporting states.
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Report to Congress on Impacts and Control ofCSOs and SSOs
Step 5. Calculate national estimates
SSO event frequency and cause-specific volumes for each non-reporting state were generated in Steps 2
through 4. These estimates were combined with the data from the reporting states and were summed to
provide a national estimate of SSO frequency and volume for each of the three scenarios examined.
G.6 Results
The results of the analyses for each of the three scenarios are summarized in Table G.5. These results
indicate that the annual frequency of SSO events is between 23,000 and 75,000 events per year, with a
corresponding volume of 3 to 10 billion gallons per year. The methodology used in developing this estimate
results in an average volume per spill of approximately 125,000 gallons, while the average volume per spill
in EPA's data management system is approximately 94,000 gallons per spill. This occurs as a direct result of
a methodology that accounts for regional differences in the cause of SSO events. Of the six states with the
highest populations and numbers of systems that did not provide data for this analysis, five (IL, NJ, NJ, OH,
and PA) are in areas of the country where higher volume wet weather SSO events are more common.
The relatively large range is due to the uncertainty regarding the extent to which communities reporting at
least one SSO event reflect all communities that had an SSO event, as the differences between Scenario la
and Scenario 2a are much greater than the differences between Scenario la and Scenario Ib. Absence of a
Scenario 2b does not seem to affect the overall range. As seen for Scenario 1, the population-based estimates
are lower than the systems-based estimates. This suggests that Scenario 2a would be greater than Scenario
2b. It is important to note that the ranges provided in Table G.5 are not necessarily all-encompassing, as the
estimates contain additional assumptions that could either raise or lower the values provided. For example,
this estimate assumes that reporting communities report every SSO event that occurred within their
community; that is, no SSO event went unnoticed and unreported. If reporting communities failed to report
any number of their SSO events, the estimates provided in Table G.5 would underestimate the true frequency
and volume of SSOs. The estimate also assumes that non-reporting communities have SSOs in the same
frequency distribution as reporting communities; this assumption could over-estimate the frequency and
volume of SSOs for non-reporting communities. There is no way to quantify the significance of these types
of assumptions, but the uncertainty introduced by these assumptions is anticipated to be small compared to
the variability already considered in the analysis. Further, EPA believes that the alternative assumptions are
more likely to affect SSO event frequency, rather than volume estimates.
Table G.5 National Estimates of SSO Frequency and Volume
_ . Estimated Number of Events Estimated SSO Volume
per Year (billion gallons)
Scenario la- systems based
Scenario Ib- population based
Scenario 2a- systems based
24,564
23,103
74,81 3
3.06
2.85
9.74
G-8
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Appendix I
Human Health Addendum
1.1 Selected Waterborne Disease
Outbreaks Documented by the Center
for Disease Control and Prevention
1.2 Interviewed Communities'and States'
Roles and Responsibilities Matrix
1.3 Selected Case Studies
1.4 Documented Concentrations of
Bacteria, Enteric Viruses, and Parasitic
Protozoa in Sewage
-------
-------
Appendix I
I.I Selected Waterborne Disease Outbreaks Documented by the Center for Disease Control and
Prevention
The CDC routinely publishes reports of waterborne disease outbreaks as part of their Mortality and
Morbidity Weekly Report Surveillance Summaries. These reports include incidents of waterborne disease
contracted through exposure to contaminated recreational waters or consumption of contaminated
drinking water, fish, or shellfish. EPA compiled reports from the Surveillance Summaries for etiologic
agents that are known to be present in untreated wastewater; however, in doing so EPA does not intend to
imply that all outbreaks listed in the following tables are related to untreated wastewater or CSO or SSO
discharges. Outbreaks are indicated in bold when untreated wastewater was specifically identified by the
CDC as contributing to the outbreak.
Table 1.1 Selected Outbreaks from Exposure to Contaminated Drinking Water
Etiologic Agent Cases State(s)/Territory Year Type of Source Water
Salmonella typhii
Giardia
Acute Gastrointestinal Illness (AGI)
Giardia
Campylobacter
Giardia
AGI
Giardia
AGI
Shigella sonnei
Norwalk-like virus
Cryptosporidium
Giardia
AGI
Giardia
Norwalk-like virus
(Setting: Resort)
Giardia
AGI
Giardia
Giardia
(Setting: Prison)
60
12
36
44
250
68
71
513
1,400
1,800
5,000
1 3,000
90
7
172
900
19
31
308
152
Virgin Islands
Maine
New Mexico
New York
Oklahoma
Vermont
New Hampshire
Pennsylvania
Puerto Rico
Puerto Rico
Pennsylvania,
Delaware, and New
Jersey
Georgia
Colorado
Colorado
Pennsylvania
Arizona
Colorado
Idaho
New York
New York
1985
1986
1986
1986
1986
1986
1987
1987
1987
1987
1987
1987
1988
1988
1988
1989
1989
1989
1989
1989
Suspected cross connection between
water and sewer MneJ
River2
River2
Lake2
Lake2
River2
Lake2
River2
Community water supply.2
Contamination of a reservoir with
sewage following a rain event and
power failure.2
For cases in Pennsylvania and Delaware,
outbreak is due to commercially
manufactured ice produced from a
contaminated water well. The outbreak
in New Jersey is also from ice from a
contaminated water well.2
River2
River2
River2
Lake2
Outbreak due to "effluent from
sewage treatment facility seeping
directly into resort's well through
cracks in the subsurface rock.
River3
Untreated surface water from a lake.3
Reservoir3
Treatment deficiencies for drinking
water from a reservoir.3
1-1
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Report to Congress on the Impacts and Control of CSOs and SSOs
Table 1.1 continued
Etiologic Agent Cases State(s)/Territory Year Type of Source Water
Giardia
E.coliO157:H7
Giardia
AGI
AGI
Giardia
AGI
AGI
AGI
Giardia
Cryptosporidium
AGI
Cryptosporidium
Cryptosporidium parvum
Cryptosporidium parvum
Giardia lamblia
Giardia lamblia
Giardia lamblia
Giardia lamblia
Cryptosporidium parvum
Giardia lamblia
Giardia lamblia
Viral outbreak (small, round-
structured virus)
Shigella sonnei
Giardia intestinalis
AGI
Cryptosporidium parvum
AGI
AGI
AGI
Eco//0157:H7
Giardia intestinalis
Giardia intestinalis
Giardia intestinalis
Norwalk-like virus
53
243
18
109
63
24
202
9,847
250
80
3,000
28
27
103
403,000
20
18
36
304
134
10
1,449
148
83
50
123
1,400
6
4
46
5
27
12
4
123
New York
Missouri
Alaska
Missouri
Pennsylvania
Vermont
Puerto Rico
Puerto Rico
Minnesota
Nevada
Oregon
Pennsylvania
Minnesota
Nevada
Wisconsin
Pennsylvania
New Hampshire
New Hampshire
Tennessee
Washington
Alaska
New York
Wisconsin
Idaho
New York
New Mexico
Texas
Florida
Florida
Washington
California
Colorado
Minnesota
New Mexico
West Virginia
1989
1989
1990
1990
1990
1990
1991
1991
1992
1992
1992
1992
1993
1993
1993
1993
1994
1994
1994
1994
1995
1995
1995
1995
1997
1997
1998
1999
1999
1999
2000
2000
2000
2000
2000
Lake3
SSO contamination of municipal
drinking water well. This outbreak
resulted in four deaths.3
River3 (Setting: Lodge)
Lake3
Lake3 (Setting: Inn)
Lake3 (Setting: Resort)
Deficiency with penitentiary
distribution system for drinking water
taken from a river.4
River4
Lake4
Lake4
Wastewater discharges and low flow
in a river used for drinking water/*
River4
River5
Lake5
Treatment deficiencies and decline in
raw water quality.5
Well contaminated with sewage.^
Reservoir5
Lake5
Reservoir5
Well contaminated with wastewater.5
Surface water contaminated by
unknown source.6
Lake6
Lake6
Sewage leak contaminated drinking
water well.6
Lake7
Sewage leak contaminated drinking
water well.7
Sewage spill contaminated drinking
water wells.7
River/Stream8
River/Stream8
River/Stream8
River/Creek8
River/Creek8
Well contaminated with sewage.**
River8
Well contaminated with sewage.**
1-2
-------
Appendix I
1 Center for Disease Control (CDC). 1988. Water-Related Disease Outbreaks, 1985. Morbidity 6- Mortality Weekly Report Surveillance Summaries. 37
(SS-2): 16-17.
2 CDC. 1990. Waterborne-Disease Outbreaks, 1986-1988. Morbidity^ Mortality Weekly Report Surveillance Summaries. 39 (SS-1): 1-13.
3 CDC. 1991. Waterborne-Disease Outbreaks, 1989-1990. Morbidity 6- Mortality Weekly Report Surveillance Summaries. 40 (SS-3): 1-21.
4 CDC. 1993. Surveillance for Waterborne-Disease Outbreaks - United States, 1991-1992. Morbidity & Mortality Weekly Report Surveillance
Summaries 42 (SS-5): 1-22.
5 CDC. 1996. Surveillance for Waterborne-Disease Outbreaks - United States, 1993-1994. Morbidity 6- Mortality Weekly Report Surveillance
Summaries 45 (SS-1): 1-33.
6 CDC. 1998. Surveillance for Waterborne-Disease Outbreaks - United States, 1995-1996. Morbidity 6- Mortality Weekly Report Surveillance
Summaries 47 (SS-5): 1-34.
7 CDC. 2000. Surveillance for Waterborne-Disease Outbreaks - United States, 1997-1998. Morbidity & Mortality Weekly Report Surveillance
Summaries 49 (SS-4): 1-35.
8 CDC. 2002. Surveillance for Waterborne-Disease Outbreaks - United States, 1999-2000. Morbidity 6- Mortality Weekly Report Surveillance
Summaries 51 (SS-8): 1-28.
1-3
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Report to Congress on the Impacts and Control of CSOs and SSOs
Table 1.2 Selected Outbreaks from Exposure to Contaminated Recreational Waters
Etiologic Agent Number Location Date Type of Recreational Water
of cases
AGI
Shigella sonnei and boydii
Norwalk-like virus
Leptospira
Shigella sonnei
Shigella sonnei
Shigella sonnei
AGI
AGI
AGI
AGI
AGI
AGI
AGI
Shigella sonnei
Shigella sonnei
AGI
Shigella sonnei
AGI
AGI
Leptospira
Adenovirus
Eco//
Shigella sonnei
Shigella sonnei
Giardia
ACI
Giardia
Giardia
Shigella sonnei
Giardia
Shigella sonnei
Shigella sonnei
Cryptosporidium parvum
Eco//
E co//
AGI
21
68
41
8
130
22
138
300
36
24
22
17
26
18
7
9
60
68
244
79
6
595
80
203
23
4
15
43
12
160
6
35
242
418
166
12
12
New York
California
California
Hawaii
South Carolina
Georgia
Pennsylvania
Vermont
Vermont
Minnesota
Maine
New Jersey
New Jersey
Minnesota
New York
Oregon
Pennsylvania
North Carolina
Washington
Wisconsin
Illinois
North Carolina
Oregon
Pennsylvania
Rhode Island
Washington
Maryland
New Jersey
Maryland
Ohio
Washington
Minnesota
New Jersey
New Jersey
New York
Illinois
Minnesota
1982
1985
1986
1987
1987
1988
1988
1988
1988
1988
1989
1989
1989
1990
1990
1990
1990
1990
1990
1990
1991
1991
1991
1991
1991
1991
1992
1993
1993
1993
1993
1994
1994
1994
1994
1995
1995
Diving in waters known to be
contaminated with human sewage
caused outbreak among New York
City Police scuba divers.
Lake2
Lake2
Stream2
Lake2
Lake2
Lake2
Lake - Recreational Area2
Lake - Swimming Area2
Lake2
Lake3
Lake3 (Setting: Park)
Lake3 (Setting: Swimming Area)
Lake3
Lake3
Lake3
Lake3
Lake3
Lake3
Lake3
Pond4
Pond linked to outbreak of
pharyngitis.4
Lake4
Lake4
Lake4
Lake4
Creek4
Lake5
Lake5
Lake5
River5
Lake5
Lake5
Lake5
Lake5
Lake6
Lake6
1-4
-------
Appendix I
Table 1.2 continued
Etiologic Agent Number Location Date Type of Recreational Water
of cases
£ co//
E.coli
AGI
Shigella sonnei
E.coli
Shigella sonnei
Shigella sonnei
Cryptosporidium parvum
AGI
E.coli
AGI
£ co//
Schistosoma spindale
AGI
£ co//
Norwalk-like virus
Cryptosporidium parvum
AGI
AGI
Norwalk-like virus
Leptospira
Shistosomes
£ co// 01 21:1-1 19
AGI
Ciardia intestinalis
Norwalk-like virus
£ co// 01 57:1-17
£ co// 01 57:1-17
£ co// 01 57:1-17
AGI
AGI
AGI
Cryptosporidium parvum
Shigella sonnei
Shigella sonnei
Leptospira
Schistosomes
Schistosomes
Schistosomes
6
2
17
70
8
39
81
3
4
6
32
8
2
650
5
30
8
41
248
18
375
2
11
25
18
168
36
5
5
2
4
32
220
15
25
21
6
4
2
Minnesota
Minnesota
Pennsylvania
Pennsylvania
Wisconsin
Colorado
Colorado
Indiana
Indiana
Minnesota
Oregon
Missouri
Oregon
Maine
Minnesota
Ohio
Pennsylvania
Washington
Washington
Wisconsin
Illinois
Oregon
Connecticut
Illinois
Massachusetts
New York
Washington
Wisconsin
California
Florida
Florida
Maine
Minnesota
Minnesota
Minnesota
Guam
California
California
Oregon
1995
1995
1995
1995
1995
1996
1996
1996
1996
1996
1996
1997
1997
1998
1998
1998
1998
1998
1998
1998
1998
1999
1999
1999
1999
1999
1999
1999
1999
2000
2000
2000
2000
2000
2000
2000
2000
2000
1999
Lake6
Lake6
Lake6
Lake6
Lake6
Lake6
Lake6
Lake6
Lake6
Lake6
Lake6
Lake7
Lake7
Lake7
Lake7
Lake7
Lake7
Lake7
Lake7
Lake7
Outbreak among triathletes exposed
to a lake.7
Lake8
Lake8
Lake8
Swimming at a pond.8
Lake8
Lake8
Lake8
Lake8
Lake8
Lake - Summary states that this
outbreak occurred from an outdoor
spring.8
Lake/pond8
Lake8
Lake/pond8
Lake8
Lake8
Pond8
Pond8
Lake8
1-5
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Report to Congress on the Impacts and Control of CSOs and SSOs
1 CDC. 1983. Epidemiologic Notes and Reports: Gastrointestinal Illness among Scuba Divers - New York City. Morbidity & Mortality Weekly
Report 32 (44): 576-577.
2 CDC. 1990. Waterborne-Disease Outbreaks, 1986-1988. Morbidity 6- Mortality Weekly Report Surveillance Summaries 39 (SS-1): 1-13.
3 CDC. 1991. Waterborne-Disease Outbreaks, 1989-1990. Morbidity 6- Mortality Weekly Report Surveillance Summaries 40 (SS-3): 1-21.
4 CDC. 1993. Surveillance for Waterborne-Disease Outbreaks - United States, 1991-1992. Morbidity & Mortality Weekly Report Surveillance
Summaries 42 (SS-5): 1-22.
5 CDC. 1996. Surveillance for Waterborne-Disease Outbreaks - United States, 1993-1994. Morbidity 6- Mortality Weekly Report Surveillance
Summaries 45 (SS-1): 1-33.
6 CDC. 1998. Surveillance for Waterborne-Disease Outbreaks - United States, 1995-1996. Morbidity 6- Mortality Weekly Report Surveillance
Summaries 47 (SS-5): 1-34.
7 CDC. 2000. Surveillance for Waterborne-Disease Outbreaks - United States, 1997-1998. Morbidity & Mortality Weekly Report Surveillance
Summaries 49 (SS-4): 1-35.
8 CDC. 2002. Surveillance for Waterborne-Disease Outbreaks - United States, 1999-2000. Morbidity & Mortality Weekly Report Surveillance
Summaries 51 (SS-8): 1-28.
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Appendix I
Table 1.3 Selected Outbreaks from Consumption of Contaminated Fish or Shellfish
Etiologic Agent Number of Location Date Exposure Pathway
cases
AGI
Norwalk-like virus
AGI
Hepatitis A
Vibrio cholerae
Norwalk-like virus
Viral gastroenteritis
Viral gastroenteritis
150
20
42
61
26
73
103
N/A
493
New York
N/A
Maine
Multiple states
Guam
Louisiana
Multiple States
Florida and
Georgia
Alabama, Florida,
Georgia, Louisiana,
and Mississippi
1982
1983
1984
1988
1990
1993
1994-
1995
1996-
1997
Fourteen separate outbreaks
of gastroenteritis due to the
consumption of raw clams. It appears
that the outbreak originated from
coastal waters in Massachusetts,
Rhode lsland,and New York due to
harvesting beds being contaminated
as a result of heavy rains during May
and JuneJ
Consumption of raw clams. ^
Consumption of Seafood Newburg.^
Consumption of raw oysters
harvested from water contaminated
by human feces.^
Consumption of contaminated reef
fish.3
A shellfish harvester with high levels
of immunoglobulin A to Norwalk-like
virus reported having been ill before
the outbreak and admitted dumping
sewage directly into harvest waters.^
December 1 994 to January 1 995, 34
clusters of cases of viral gastroenteritis
were traced to shellfish harvested to
beds in Florida's Apalachicola Bay. The
source of the Norwalk-like virus was
attributed to sewage contamination
either from land-based sources or
recreational or commercial vessels,
according to preliminary findings.-*
Consumption of oysters thought
to have been contaminated by
harvesters improperly disposing of
sewage. ^
CDC. 1982. Epidemiologic Notes and Reports: Enteric Illness Associated with Raw Clam Consumption - New York. Morbidity & Mortality Weekly Report 31 (33):
449-451.
2CDC. 1990. Foodborne Disease Outbreaks, 5-Year Summary, 1983-1987. Morbidity 6- Mortality Weekly Report Surveillance Summaries 39 (SS-01): 15-23.
3 CDC. 1996. Surveillance for Foodborne-Disease Outbreaks, United States, 1988-1992. Morbidity 6- Mortality Weekly Report Surveillance Summaries 45 (SS-05): 1-55.
CDC. 1993. Multistate Outbreak of Viral Gastroenteritis Related to Consumption of Oysters - Louisiana, Maryland, Mississippi, and North Carolina,1993. Morbidity
6- Mortality Weekly Report 42 (49): 945-948.
CDC. 1995. Epidemiologic Notes and Reports: Multistate Outbreak of Viral Gastroenteritis Associated with Consumption of Oysters - Apalachicola Bay, Florida,
December 1994-January 1995. Morbidity 6- Mortality Weekly Report 44 (2): 37-39.
6 CDC. 1997. Viral Gastroenteritis Associated with Eating Oysters - Louisiana, December 1996-January 1997. Morbidity 6-Mortality Weekly Report 46 (47): 1109-1112.
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Report to Congress on the Impacts and Control of CSOs and SSOs
1.10
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Appendix I
1.2 Interviewed Communities' and States' Roles and Responsibilities Matrix
As part of this report effort, EPA conducted a series of interviews with officials in state and local
governments. Through the interviews, EPA sought a clearer understanding of the roles and responsibilities
of these agencies in preventing, tracking, and monitoring for potential human health impacts associated
with CSO and SSO discharges within their jurisdiction. The results of these interviews are summarized in
the following two tables.
Table 1.4 Local Agency Responsibilities Related to Human Health as Identified During Community
Interviews
Community Waterborne Recreational Wastewater Drinking Water Monitoring Fish
Illness Water Monitoring Treatment Monitoring and Shellfish
Investigations & Posting
Boston, MA
Portland, ME
Cape May, NJ
New York, NY
Arlington, VA
Erie County, PA
Pittsburgh, PA
Atlanta, GA
Ft. Pierce, FL
Akron, OH
Milwaukee, Wl
City Health
City Health
Department
State Health
Department
County Health
City Health
Department
City
Environmental
Agency
County Health
Department
County Health
Department
County Health
Department
County Health
Epidemiology &
Environmental
Division
County Health
Departments
City Health
Department
City Health
Department
Metropolitan
District
Commission and
MWRA
State
Environmental
Agency
County Health
State
Environmental
Agency
N/A
County Health
Department
State
Environmental
Agency
County Health
Environmental
Division
County Health
Departments
N/A
City Health
Department
MWRA
Public Works
County
Municipal
Utilities
Authority
City Public
Works
State
Environmental
Agency
County
Environmental
Health
Department
Public Works
Drinking and
Wastewater
Agency
Each
municipality
County Health
Dept, State
Environmental
Agency
Waste Treatment
Agency
MWRA
Water District
Individual Water
Utilities, County
Health State
Environmental
Agency
City
Environmental
Agency
State
Environmental
Agency
Public Works
Water District
Drinking and
Wastewater
Agency
Each
municipality
County Health
Department
State DEP
State
Environmental
Agency
State
Environmental
Agency
State
Environmental
Agency
N/A
N/A
Local Level
Environmental
Health
State
Environmental
Agency
State
Environmental
Agency
1-11
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Report to Congress on the Impacts and Control of CSOs and SSOs
Table 1.4 continued
Community Waterborne Recreational Wastewater Drinking Water Monitoring Fish
Illness Water Monitoring Treatment Monitoring and Shellfish
Investigations & Posting
Austin,TX
Little Rock,AR
Tulsa,OK
Omaha, NE
St. Louis, MO
Denver, CO
Las Vegas, NV
Los Angeles, CA
Orange County, CA
San Diego, CA
Portland, OR
Seattle, WA
City/County
Health
Department
State Health
Department
County Health
Department
& State Health
Department
County Health
Department
City Health
Department
City/County
Environmental
Agency
County Health
Department,
Water Authority
State Health
Department,
City Health
Department
County Health
Department
Epidemiology
County
Environmental
Health,
Department
of Health
Epidemiology
State Health
Department
County Health
Department
Watershed
Protection Division
State
Environmental
Department
State
Environmental
Department
County
City/County
Environmental
Agency
Water Authority
National Parks
Service
City Health
Department
County Health
Department
Environmental
County Sanitation
District Wastewater
Authority
County
Environmental
Health
State Health
Department
(ocean beaches
only) State
Environmental
Agency
local
municipalities
City Government
Local
Wastewater
Treatment
Local sanitation
districts
Local water
and sanitation
districts
Municipal
POTWs
State
Environmental
Agency (or
the Native
American tribes,
if treatment is
associated with
tribal lands)
State
Environmental
Department
City Government
Public Works
Water Authority
State Health
Department,
City Health
Department
Water Authority
under
jurisdiction
of State
Department of
Health
Local water
purveyor
and State
Department of
Health
State Health
Department
- monitor
groundwater in
general
State
Environmental
Department
State
Environmental
Department
County Health
Department
State Health
Department
State
Department of
Health Services/
Biotoxin
Monitoring
State
Department
of Health
and County
Environmental
Health
State
Environmental
Agency
Department of
Agriculture
1-12
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Appendix I
Table 1.5 State Agency Responsibilities Related to Human Health, as Identified During Interviews
Waterborne
Illness
Investigations
Recreational
Water
Monitoring &
Posting
Wastewater Drinking Water Monitoring Fish
Treatment Monitoring and Shellfish
New Jersey
Pennsylvania
Florida
Massachusetts
Missouri
Wisconsin
Oregon
State Department
of Health
State Health
State Department
of Health
Local Boards
of Health, State
Department of
Health
Department of
Health
State Department
of Health and local
health agencies
State Health
Department State
Environmental
Agency
State
Environmental
Agency and
Local Health
Departments
State
Environmental
Protection, State
Department of
Health
County health
officers
Local Boards
of Health, State
Department of
Health
Local or state
agency that"owns
the beach"
State Health
Department
(ocean beaches
only)
State
Environmental
Agency
State
Environmental
Protection
State
Environmental
Agency permits
the wastewater
program
Local Boards
of Health, State
Environmental
Agency
State
Environmental
Agency
Local
Government
State
Environmental
Agency (or
the Native
American tribes,
if treatment is
associated with
tribal lands)
State
Environmental
Agency and
Local Health
Departments
State
Environmental
Protection, State
Department of
Health
State
Environmental
Agency
oversight for
drinking water
suppliers
State
Environmental
Agency
State
Environmental
Agency
Local
Government
State Health
Department
- monitor
groundwaterin
general
State
Environmental
Agency
Department of
Agriculture
The Dept. of
Agriculture,
DOH issues
the health
advisories. State
environmental
agency
does tissue
monitoring
State
Environmental
Agency- Division
of Marine
Fisheries, State
Department of
Health
State
Environmental
Agency
State
Environmental
Agency
Department of
Agriculture
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Report to Congress on the Impacts and Control of CSOs and SSOs
1-14
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Appendix I
1.3 Selected Case Studies
A Case Study of the 1993 Milwaukee Cryptosporidiosis Outbreak
Background
In the spring of 1993, the City of Milwaukee, Wisconsin and surrounding areas saw a marked increase
in absenteeism and reported cases of diarrhea (MacKenzie 1994). Clinical investigations found that
residents were suffering from Cryptosporidiosis, a diarrheal disease caused by a microscopic parasite,
Cryptosporidium parvum. This parasite can live in the intestines of humans and other mammals and
can be passed in the feces of an infected individual (CDC 2003a). It is estimated that more than 400,000
people were infected during this outbreak; more than 600 persons had laboratory confirmed cases
(MacKenzie 1994).
About Cryptosporidiosis
Cryptosporidiosis, caused by the parasite Cryptosporidium parvum, is a disease affecting many
large mammals. Its symptoms include, diarrhea, abdominal cramps, loss of appetite, low-grade
fever, nausea, and vomiting (CDC 2003a). Cryptosporitiosis is highly contagious and is passed via
fecal oral contamination from one host to another. Cryptosporidium oocysts are very resistant to
disinfection and can survive outside of a host for a long period of time. Cryptosporidium oocysts
are found throughout the United States in soil, animal waste, and water (CDC 2003a). Once
ingested by the host, the parasite attacks the small intestine and rapidly reproduces.
Incubation takes two to fourteen days from the initial infection. For individuals with healthy
immune systems, the infection will last approximately two weeks; however, symptoms may
cycle and the individual can appear to get better and then experience a relapse (CDC 2003a).
The disease is potentially fatal for immunocompromised individuals. In those individuals the
symptoms may last longer, and the disease may reappear after white blood cell numbers drop
(CDC2003b).
It is estimated that in industrialized countries, approximately 0.4% of the population pass
Cryptosporidium parvum oocysts at any one given time, and of patients admitted to hospitals for
diarrhea, 2-2.5% have Cryptosporidiosis. Further, 30-35% of the U.S. population has antibodies
for Cryptosporidium parvum, evidence that they have been exposed to the parasite at some point
(Upton 2001).
Exposure Pathway and Source of Parasite
The Milwaukee Cryptosporidiosis outbreak was caused by ingestion of contaminated water from Lake
Michigan. The Milwaukee Water Works (MWW) supplies water, obtained from Lake Michigan, to the
City of Milwaukee and nine surrounding municipalities via two water treatment plants, one located in the
northern part of the district and the other in the south.
Beginning on approximately March 21, 1993, and continuing through April 9, the southern treatment
plant reported increases in the turbidity of treated water, rising from a low of 0.25 NTU to a peak of 1.7
NTU. This finding, coupled with the fact that a majority of the laboratory and clinically confirmed cases
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Report to Congress on the Impacts and Control of CSOs and SSOs
of Cryptosporidiosis were from households predominately supplied by the southern water treatment
plant, led investigators to conclude that contaminated water from Lake Michigan was not properly
filtered and was supplied to, and ingested by, residents in the southern plant treatment service area.
(MacKenzie 1994) Although the environmental source of the parasite is not known, inferences include
agricultural run-off, slaughterhouses, and untreated wastewater leaks (MacKenzie 1994).
Tracking, Reporting, and Response
On April 5, 1993, the Milwaukee Department of Health contacted the Wisconsin Division of Health
after widespread absenteeism in key professions was reported. On April 7, 1993, two laboratories in
the Milwaukee area identified Cryptosporidium oocysts in stool samples. On the evening of April 7,
1993, a boil water advisory was issued and the southern plant was temporarily closed on April 9, 1993
(MacKenzie 1994). Although the MWW was within required water quality limits, a streaming-current
monitor, which helps determine the amount of coagulant needed for filtration, was not installed
correctly. This was quickly fixed.
Impact
It is estimated that over 400,000 people were infected with Cryptosporidiosis (MacKenzie 1994).
Their symptoms included: cramps, malaise, nausea, decreased appetite, weight loss, muscle pain, and
rash (Frisby 1997). These symptoms resulted in decreased productivity and it was reported that the
"gastrointestinal illness resulted in widespread absenteeism among hospital employees, students, and
schoolteachers" (MacKenzie 1994).
Additional Comment
The Milwaukee outbreak helped identify shortcomings of the waterborne disease outbreak surveillance
system that was in operation in the United States. Researchers suggested that laboratories should perform
routine stool tests for Cryptosporidium when patients' symptoms warranted (Mac Kenzie 1994). They
also suggested that the Cryptosporidium tests were not sensitive enough and should be repeated in order
to account for the time needed for the Cryptosporidium oocysts to enter the feces (Cicirello 1997). Most
importantly, at the time of the Milwaukee outbreak, Cryptosporidiosis was not legally required to be
reported to state health officials. As a result of this, and other outbreaks, Cryptosporidiosis is now a
"reportable illness" in many jurisdictions.
1-16
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Appendix I
A Case Study of the 1998 Brushy Creek Cryptosporidiosis Outbreak
Background
On July 13, 1998, a lightning strike during a thunderstorm incapacitated the controls at a wastewater lift
station located upstream from the Brushy Creek Municipal Utility District's (MUD) five drinking water
wells. This power outage caused 167,000 gallons of raw sewage to flow into Brushy Creek (TDH 1998).
Beginning on July 24, 1998, the Texas Department of Health Infectious Disease Epidemiology and
Surveillance Division (IDEAS) and the Williamson County and Cities Health Districts began to receive
calls from Brushy Creek residents complaining of nausea, diarrhea, and abdominal cramps. It was later
determined that residents of Brushy Creek were suffering from Cryptosporidiosis. It is estimated that 60
percent of Brushy Creek's population of 10,000 were exposed to the parasite and approximately 1,440
residents contracted Cryptosporidiosis (TDH 1998).
Exposure Pathway and Source of Parasite
The Brushy Creek Cryptosporidiosis outbreak was caused by ingestion of contaminated water from
the Brushy Creek MUD wells. It was reported that MUD customers whose water came from the
contaminated wells were five times more likely to be ill than MUD customers whose water came from
treated surface water (TDH 1998). Fecal coliform tests performed on raw water samples taken from the
five wells after the sewage leak showed high levels of E. coli and helped to confirm that the wells had been
contaminated (four of the five wells were positive) (TDH 1998).
Tracking, Reporting, and Response
In response to the massive sewage spill, the Texas Natural Resources Conservation Commission (TNRCC)
instructed the Brushy Creek MUD to test its five water wells for fecal coliform (July 17). Based on results
of those tests, received on July 21, the Brushy Creek MUD was ordered to take all the wells off-line and
purchase water from the city of Round Rock. On July 24, 1998, the Texas Department of Health and local
health districts began receiving residents' complaints of symptoms related to gastrointestinal disease,
and TNRCC contacted the Texas Department of Health to request assistance with a possible waterborne
disease outbreak in Williamson County (TDH 1998). In cooperation with local health departments,
IDEAS distributed specimen containers to Brushy Creek residents in order to obtain stool samples. Twelve
of the specimen containers were returned, all were tested and found negative for viral and bacterial
pathogens, six however, were positive for Cryptosporidium parvum (TDH 1998).
Impact
It is estimated that 1,440 people suffered from Cryptosporidiosis during this outbreak (there were 89
laboratory confirmed cases). The infected persons complained of nausea, diarrhea, and abdominal
cramps. Based on a residents survey, the mean duration of the illness was seven days (range 1- 45 days)
(TDH 1998).
Additional Comments
Brushy Creek MUD wells are 100 feet deep and encased in cement. It is generally thought that these types
of wells would not be influenced by surface water. This presumption is probably the reason residents
of Brushy Creek were supplied water from the contaminated well for approximately eight days. This
outbreak illustrates that even wells with this degree of protection can be contaminated by surface water
(TDH 1998).
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Report to Congress on the Impacts and Control of CSOs and SSOs
Forty-five additional cases of Cryptosporidiosis were reported in the Brushy Creek area between
September 1 and December 31, 1998. It was not possible to determine if these cases would have occurred
without the earlier water contamination because no reliable data were collected to establish a normal rate
of Cryptosporidiosis in Texas.
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Appendix I
A Case Study of the 1995 Idaho Shigellosis Outbreak
Background
In August 1995 the local health department requested that the Idaho Department of Health investigate
reports of diarrheal illness among resort visitors in Island Park, Idaho. Clinical investigations found that
these individuals were suffering from Shigellosis, a diarrheal disease caused by a microscopic parasite,
Shigdla sonnei (CDC 1996). This parasite can live in the intestines of humans and other mammals and
can be passed in the feces of an infected organism. (CDC 2003c). Eighty-two cases were identified amon^
visitors to the resort as well as a few cases among local residents (CDC 1996).
About Shigellosis
Shigellosis, caused by the parasite Shigella sonnei, is a well-recognized cause of gastrointestinal
illness in humans and is the most common cause of bacillary dysentary in the United States
(CDC 2003c). Symptoms include diarrhea, fever, abdominal pain, and blood or mucus in the
stool. Most outbreaks of Shigellosis are attributed to person-to-person transmission, however,
the disease has also been reported to spread through food, water, and swimming (CDC 2003c).
Waterborne outbreaks are commonly associated with wells that have been fecally contaminated.
However, because Shigella organisms rarely are isolated from water sources, the identification of a
waterborne source usually is based on epidemiologic evidence (CDC 2003c).
Most people who are infected with Shigella develop diarrhea, fever, and stomach cramps starting
a day or two after they are exposed. The diarrhea usually resolves in five to seven days. In some
persons, especially young children and the elderly, the diarrhea can be so severe that the patient
needs to be hospitalized. Some persons who are infected may have no symptoms at all, but may still
pass the bacteria to others.
Approximately 14,000 laboratory confirmed cases of shigellosis and an estimated 448,240 total
cases (mostly due to Shigella sonnei) occur in the United States each year (CDC 2003d). This
disease is very common in developing countries and, depending on the strain, can be deadly.
Further, Shigella has, in some areas, become resistant to antibiotics.
Exposure Pathway and Source of Parasite
The Island Park Shigellosis outbreak was probably caused by the ingestion of contaminated well water.
Testing of wells in the neighborhood indicated that a number of the wells were contaminated with
fecal coliform bacteria (CDC 1996). While cultures did not indicate the presence of Shigella sonnei, it
is known that Shigella organisms are rarely successfully isolated from water sources. Identification of a
waterborne source is generally based on epidemiologic evidence (CDC 1996). Plasmid profile analyses
indicated that the Shigella organisms were of the same strain in both the infected resort visitors and the
infected neighbors. This suggests that the organisms may have been transmitted from multiple wells in
the same area through common groundwater (CDC 1996). The water table in the area was higher than
normal due to increased rainfall levels during the spring. Inspection of a nearby sewer line found that the
wastewater was not draining properly, but no specific leaks were identified when sections were excavated
for inspection (CDC 1996).
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Report to Congress on the Impacts and Control of CSOs and SSOs
Tracking, Reporting, and Response
After receiving reports of diarrheal illness among guests at the resort, the local health department
recommended several prevention measures before initiating the investigation (CDC 1996). On August
17, the resort posted warning signs at water taps cautioning against drinking water; on August 19, food
service was terminated; and on August 21, bottled water was placed in every room. Resort water is
supplied by one well, which was dug in 1993 (CDC 1996). Samples of water obtained from the well on
August 23 were positive for fecal coliform bacteria; however, cultures were negative for Shigella. After this
testing was completed the local health department required that the resort provide bottled or boiled water
to visitors and recommended that persons residing in the area have their well water tested and boil all
drinking water. Since the investigation, the resort has drilled a new and deeper well (CDC 1996).
Impact
Eighty-two cases were identified among resort visitors and six cases were identified among individuals in
neighboring houses. After testing well water throughout the neighborhood the local health department
recommended that residents have their well water tested and a boil water advisory was put into effect. No
specific source of Shigella organisms was ever identified.
Additional Comments
Routine water-quality testing, including testing for fecal coliform bacteria, is the most practical indicator
of possible bacterial contamination of drinking water from both community and private water supplies.
However, many privately owned wells are never tested for fecal coliform bacteria (CDC 1996). In
addition, timely testing, reporting, and follow-up in cases of contaminated public water systems are often
constrained by limited resources available to local health departments (CDC 1996).
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Appendix I
A Case Study of the 1993 Las Vegas Cryptosporidiosis Outbreak
Background
Over a seven month period in 1993 and 1994, Clark County, Nevada, which includes Las Vegas,
experienced a rise in the number of HIV-infected individuals with diarrheal disease. Clinical
investigations found that these individuals were suffering from Cryptosporidiosis. There was no estimate
of the number of individuals infected during the course of this outbreak (Goldstein 1996).
Exposure Pathway and Source of Parasite
The Clark County Cryptosporidiosis outbreak was most likely caused by ingestion of contaminated water
from Lake Mead. The water treatment plant serving Clark County supplies water, obtained from Lake
Mead, to the City of Las Vegas and the rest of the county (Goldstein 1996). It was not reported to be
malfunctioning at any point during the seven month outbreak period. The maximum recorded turbidity
value during the outbreak period reached 0.17 NTU, as compared with the 1.7 NTU value recorded
during the 1993 Milwaukee Cryptosporidiosis outbreak (Goldstein 1996).
Due to the widespread geographic nature of the infected patients, it is assumed that the municipal
drinking water supply was contaminated before reaching the treatment plant (Goldstein 1996). While
the water was filtered and chlorinated at the treatment plant some Cryptosporidium oocysts survived
the process and entered the municipal drinking water system. This is not surprising considering the
resistance of Cryptosporidium oocysts to chlorination. Individuals then were exposed. The lack of positive
test results for this parasite in the water supply, coupled with the persistence of this outbreak suggest an
intermittent, low-level of contamination of the water.
Tracking, Reporting, and Response
Because water quality exceeded all standards, waterborne transmission of this parasite was not suspected
and no advisory warning residents to boil their water was issued. This situation remained unchanged for
approximately fourteen weeks after the possible outbreak was first noted in mid-March 1993 (Goldstein
1996).
The fact that Cryptosporidiosis is a reportable disease in Nevada combined with the awareness of
physicians regarding the sensitivity of immunocompromised patients to exposure to this disease led to
recognition of an outbreak that might have otherwise not been reported (Goldstein 1996). Generally,
the appropriate laboratory tests that would identify Cryptosporidiosis infection are not carried out
unless a physician is aware of a source of contamination in the community or if they are dealing with an
individual who is particularly sensitive to this type of disease.
Impact
There is no estimate of the number of people infected during the course of this outbreak. A much higher
incidence of reported infections occurred among HIV-infected individuals. The short-term mortality rate
for the HIV-infected adults who had Cryptosporidiosis was high. Two thirds of those who died during
or shortly after the outbreak had Cryptosporidiosis listed on their death certificates. These data do not
differentiate dying "of" from dying "with" Cryptosporidiosis. For these HIV-infected case-patients early
mortality was higher, but one year mortality was not when compared with a HIV-positive, but non-
Cryptosporidium exposed control group (Goldstein 1996).
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Report to Congress on the Impacts and Control of CSOs and SSOs
Additional Comments
Laboratories do not routinely test for this type of infection as this diagnosis is rarely considered when
not dealing with an immunosuppressed patient. Researchers suggest that the public health significance
of waterbome-Cryptosporidium infection in the United States must be determined. To accomplish this
task epidemiologists need more sensitive and rapid methods for detecting oocysts in water, workable
surveillance systems able to detect cases associated with low-level transmission of Cryptosporidium,
and epidemiologic studies specifically designed to address the risk for waterborne transmission of
Cryptosporidium in nonoutbreak settings (Goldstein 1996).
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Appendix I
A Case Study of the 1985 Braun Station, Texas Cryptosporidiosis Outbreak
Background
In a period between May and July 1984 two distinct gastroenteritis outbreaks were identified in the
community surrounding Braun Station, Texas (D'Antonio 1985). Clinical investigations found that
individuals impacted during the first outbreak were suffering from Norwalk virus and those impacted
during the second outbreak were suffering from Cryptosporidiosis. This parasite can live in the intestines
of humans and other mammals and can be passed in the feces of an infected organism. (CDC 2003a).
Cryptosporidium oocysts were identified in 47 of 79 tested Braun Station patients (D'Antonio 1985).
Oocycsts were also identified in samples from 12 patients suffering from gastroenteritis, but who did not
reside in Braun Station.
Exposure Pathway and Source of Parasite
No geographical clustering or age-related patterns emerged upon examination of the July
Cryptosporidiosis outbreak in Braun Station. However, consumption of tap water was greater among
those afflicted and individuals who were not in the area during the month of July were generally not
infected (D'Antonio 1985). Public drinking water is drawn from an artesian well that is not filtered, but
is chlorinated shortly before distribution. The outbreak was investigated as it occurred. Well water is
generally not tested in this region of Texas, but community complaints convinced authorities to begin
testing in mid-June. Chlorinated water samples were found to be coliform-negative. However, untreated
well water samples tested had fecal coliform counts as high as 2600/100 mL (D'Antonio 1985). A boil
water advisory was put into effect. Subsequent dye tests indicated that the community's wastewater system
was leaking into the well water. Attempts to identify the exact site of contamination were not successful.
The pattern of repeated outbreak but differing major causative agent suggested that contamination of the
water supply was intermittent (D'Antonio 1985). The community was provided with an alternate water
supply.
Tracking, Reporting, and Response
A cluster of patients suffering from gastroenteritis in Braun Station led to the recognition of both
outbreaks. Community-requested water testing and subsequent dye tests identified wastewater
contamination of the community's well water. A boil water advisory was issued after evidence of
contaminated water was gathered. When the source of the wastewater could not be identified and
stopped, an alternative water source was provided to the community. The differing types of causative
agents at the root of each outbreak suggested intermittent water supply contamination.
Impact
Symptoms associated with Cryptosporidiosis infection were experienced by an estimated 2,006 patients
in Braun Station. Once the source of infection was identified, proper steps were taken to ensure that the
community was supplied with a healthy water supply.
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Report to Congress on the Impacts and Control of CSOs and SSOs
References for Case Studies
Bitton, G. 1980. Introduction to Environmental Virology. New York, NY: John Wiley & Sons.
Centers for Disease Control and Prevention (CDC). 1996. Shigella sonnei Outbreak Associated with
Contaminated Drinking Water- Island Park, Idaho, August 1995. Morbidity and Mortality Weekly Report
45(11): 229-234.
CDC. 2003a. "Parasitic Disease Information Fact Sheet: Cryptosporidiosis." Retreived May 12, 2003b.
http:://www.cdc.gov/ncidod/dod/parasites/cryptosporidiosis/factsheet cryptosporidiosis.htm.
CDC. 2003b. "Preventing Cryptosporidiosis: A Guide for People With Compromised Immune Systems."
Retreived May 12, 2003c.
http://www.cdc.gov/ncidod/dpd/parasites/cryptosporidiosis/factsht crypto prevent ci.htm.
CDC. 2003c. "Disease Information: Shigellosis". Retrieved September 2003.
http://www.cdc.gov/ncidod/dbmd/diseaseinfo/shigellosis g.htm.
Cicirello H.G., et. al. 1997. Cryptosporidiosis in Children During a Massive Waterborne Outbreak in
Milwaukee, Wisconsin: Clinical, Laboratory, and Epidemiologic Findings. Epidemiol Infect 119(1):53-60.
D'Antonio, R.G., et al. 1985. A waterborne outbreak of Cryptosporidiosis at Brushy Creek. Epidemiology
in Texas, 1999 Annual Report. Annals of Internal Medicine 103(6): 886-888.
Frisby, H.R. 1997. Clinical and Epidemiologic Features of a Massive Waterborne... Journal of Acquired
Immune Deficiency Syndromes and Human Retrovisrus 16 (4-5): 223-422.
Goldstein, S.T., et al. 1996. Cryptosporidiosis: An Outbreak Associated with Drinking Water Despite State-
of-the-Art Water Treatment. Annals of Internal Medicine 124(5):459-968.
MacKenzie W.R., et. al. 1994. A Massive outbreak in Milwaukee of Cryptosporidium infection transmitted
through the public water supply. N English journal of Medicine. 331:161-7.
Texas Department of Health (TDH). 1998. Cryptosporidiosis at Brushy Creek. Epidemiology in Texas,
1999 Annual Report.
http://www.tdh.state.tx.us/epidemiology/98annual/reports/crypto.pdf.
Upton, S.J. 2001. Cryptosporidium: they probably taste like chicken. Presented at the Cryptosporidium from
Molecules to Disease Conference, Fremantle, Western Australia, October 7-12,2001. (Cited in Text Box 1:
About Cryptosporidiosis)
1-24
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Appendix I
1.4 Tables showing various concentrations of pathogenic bacteric, enteric viruses, and parasitic protozoa
in sewage.
Table 1.6 Concentrations of Common Pathogenic Bacteria in Sewage
Bacteria Concentration in Sewage (per lOOmL) Reference
Camplyobacter
Pathogenic E.coli
Salmonella
S. typhi
Shigella
Vibrio cholera
Vibrio non-cholera
Yersinia
3,700
10,000-100,000
1,321,594 (30,000-6,200,000)
1,000,000-10,000,000
1,190,000
2,500,000
3,180,000
4,120,000
2,880,000
1,600,000
2,170,000
2.3-8,000
240-1,200
93-1,100
1,100-11,000
150-1,100
100-10,000
400-8,000
8,000
528
400-1,200
500-8,000
418
0.2-8,000
13
62
>190
45
<20
170
<40
-
1-1,000
1-1,000
1,000
1-1000
0.1-1,000
-
10-10,000
-
Holler 1988
WHO 2003
Payment 2001
WHO 2003
Gore etal. 1999
NAS 1 993
Koivunen 2003
NRC1998
EPA 1 992
NRC1996
Bitton 1 980
Pettygrove and Asano 1 985
Yates 1 994
Payment and Franco 1 993
WHO 2003
Gore etal. 1999
-
NAS 1 993
EPA 1 992
NRC1996
NRC1998
WHO 2003
-
NAS 1 993
-
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Report to Congress on the Impacts and Control of CSOs and SSOs
Table 1.7 Concentrations of Enteric Viruses Present in Sewage
Virus Group Concentration in Sewage Reference
(per lOOmL)
Adenovirus
Astrovirus
Noravirus (includes Norwalk-like
viruses)
Echovirus
Enterovirus (includes polio,
encephalitis, conjunctivitis, and
coxsackie viruses)
1 0-1 0,000
-
—
-
1 8.2-9,200
>0.720
23
4.5
96.2(0.4-1,251)
1,000-10,000
1.085
1
7
5
40
2
1
1.1
1 00-50000
7 (0.75-80)
1.98
0.05
14.8
3.95
6.91
3.95
50,000
1 00-49,200
10,000-100,000
0.284
0.42
1 0,000
NAS1993
-
—
-
NAS1993
Rose 2001 a
Payment etal. 2001
NRC1998
Rose 2001 (WER article)
EPA 1992
Hej kali 984
Smith and Gerba 1982
NRC1996
Pettygrove and Asano 1985
Yates 1 994
Payment and Franco 1993
Rose 1 996
Wyn-Jones and Sellwood 2001
1-26
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Appendix I
Table 1.7 continued
Virus Group Concentration in Sewage (per Reference
lOOmL)
Reovirus
Rotavirus
0.1-124.7
40.1
0.98(0.1-32.1)
9.6
9.6
6.7
17.4
1.5
400-85,000
NAS 1 993
NAS 1 993
Hejkaletal.1984
Smith and Gerba 1982
WHO 2003
1-27
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 1.8 Concentrations of Common Parasitic Protozoa Present in Sewage
Parasitic Protozoa Concentration in Sewage (per L) Reference
Cryptosporidium
Entamoeba
10-1000
47.7
6(1-560)
<40-625
226.0
60 (3-400)
20 (0-3,000)
20
17
<4.348
8.16
9.52
14.84
15
0.3
2
1
15
15
7.42
40
280
160
80
120
3.7
69.1
1-390
<2-24
0
0
<2
2
<2-8
<2-8
<2-24
4.1-13,700
28-52
0-100
4.0
4
NAS 1 993
Chauret1999
Payment 2001
Mahinand Pancorbo 1999
Rose 2001 a
NRC1998
Rose 2001 b
Payment and Franco 1 993
LACountySD2003
Rose 1996
Gennaccaro et al. 2003
WHO 2003
McCuin and Clancy 2004
NAS 1 993
EPA 1 992
Bitton 1980
WHO 2003
1-28
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Appendix I
Table 1.8 continued
Parasitic Protozoa Concentration in Sewage (per L)
Reference
Giardia
530-100,000
82.5
1,165(100-9,200)
390
315
10-13,600
642-3,375
354 (90-2,830)
290(40-1,140)
200
480
200
220
42.86
490
69
39
325
2
69
490
13.76
29,000
19,000
16,000
27,000
32,000
4,760
5,080
15,560
9,760
19,280
500-100,000
100,000
9,000-200,000
39
125-200,000
NAS1993
Chauret1999
Payment 2001
Mahin and Pancorbo 1999
Rose 2001 a
NRC1998
Rose 2001b
Payment and Franco 1993
LA County SD 2003
EPA 1992
NRC1996
Yates 1994
Rose 1996
WHO 2003
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Report to Congress on the Impacts and Control of CSOs and SSOs
References for Tables 1.6 -1.8
Bitton, G. 1980. Introduction to Environmental Virology. New York, NY: John Wiley & Sons.
Chauret, C, et al. 1999. Fate of Cryptosporidium oocysts, Giardia cysts, and microbial indicators during
wastewater treatment and anaerobic sludge digestion. Canadian Journal of Microbiology 45:257-151.
Environmental Protection Agency (EPA). 1992. Manual: Guidelines for Water Reuse. EPA 625/R-92/004.
Gennaccaro, A.L., et al. 2003. Infectious Cryptosporidium parvum oocysts in final reclaimed effluent. Applied
and Environmental Microbiology 69(8): 4983-4984.
Gore, R., et al. 1999. Report No. 99-17: Bacteria in raw sewage and viable helminth ova in raw sewage and
primary sludge at the water reclamation plants of the Metropolitan Water Reclamation District of Greater
Chicago. Metropolitan Water Reclamation District of Greater Chicago Research and Development
Department. Chicago, IL.
Hejkal, T.W, et al. 1984. Seasonal occurrence of rotavirus in sewage. Applied and Environmental Microbiology
47(3): 588-590.
Holler, C. 1988. Quantitative and qualitative investigations of Campylobacter in a sewage treatment plant.
Zentralblatt fur Bakteriologie, Mikrobiologie und Hygiene. Serie B 185: 326-339.
Koivunen, J., et al. 2003. Elimination of enteric bacteria in biological-chemical wastewater treatment and
tertiary filtration units. Water Research 27: 690-698.
Los Angeles County Sanitation Districts. 2003. Memo containing a summary of various Giardia cyst and
Cryptosporidium oocyst data sets compiled by the San Jose Creek Water Quality Laboratory over the previous
nine years. July 21, 2003.
Mahin, T., and Pancorbo, O. 1999. Waterborne pathogens: more effective analytical and treatment methods
are needed for pathogens in wastewater and stormwater. Water Environment and Technology 11(4): 51-55.
McCuin, R.M. and Clancy, J.L. 2004. Cryptosporidium Occurrence, Removal and Inactivation Methods for
Wastewaters. Final Report: Water Environment Research Foundation, Project 98-HHE-l, Alexandria, VA. In
press.
National Academy of Sciences (NAS). 1993. Managing Wastewater in Coastal Urban Areas. Washington, D.C:
The National Academies Press.
National Research Council (NRC), Committee on the Use of Treated Municipal Wastewater Efflents and
Sludge in the Production of Crops for Human Consumption. 1996. Use of Reclaimed Water and Sludge in
Food Crop Production. Washington, D.C: The National Academies Press.
National Research Council (NRC), Committee to Evaluate the Viability of Augmenting Potable Water
Supplies with Reclaimed Water. 1998. Issues in Potable Reuse: The Viability of Augmenting Drinking Water
Supplies with Reclaimed Water. Washington, D.C: The National Academies Press.
1-30
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Appendix I
Payment, P., and Franco, E. 1993. Clostridium perfringens and somatic coliphages as indicators of the
efficiency of drinking water treatment for viruses and protozoan cysts. Applied and Environmental
Microbiology 59(8): 2418-2424.
Payment, P., et al. 2001. Removal of indicator bacteria, human enteric viruses, Giardia cysts, and
Cryptosporidium oocysts at a large wastewater primary treatment facility. Canadian Journal of
Microbiology 47: 188-193.
Pettygrove, G.S., and Asano, T. 1985. Irrigation with Reclaimed Municipal Wastewater—A Guidance
Manual. Prepared by the Department of Land, Air, and Water Resources, University of California, Davis
for the California State Water Resources Control Board. Ann Arbor: Lewis Publishers, Inc. (Reprint).
Rose, J.B., et al. 1996. Removal of pathogenic and indicator microorganisms by a full-scale water
reclamation facility. Water Research 30(11): 2785-2797.
Rose, J.B., et al. 200 la. Reduction of pathogens, indicator bacteria, and alternative indicators by wastewater
treatment and reclamation processes. Water Environment Research Federation. Project Number 00-PUM-
2T.
Rose, J.B., et al. 200Ib. Reduction of enteric microorganisms at the Upper Occoquan Sewage Authority
Water Reclamation Plant. Water Environment Research 73(6): 711-720.
Smith, E.M., and Gerba, C.P. 1982. Development of a method for detection of human rotavirus in water
and sewage. Applied and Environmental Microbiology 43(6): 1440-1450.
World Health Organization (WHO). 2003. Guidelines for Safe Recreational Water Environments, Volume I:
Coastal and Fresh Waters. Geneva: World Health Organization.
Wyn-Jones, A.P., and Sellwood, J. 2001. Enteric viruses in the aquatic environment. Journal of Applied
Microbiology 91: 945-962.
Yates, M.V. 1994. Monitoring concerns and procedures for human health effects. In: Wastewater Reuse for
Golf Course Irrigation. Ann Arbor: Lewis Publishers.
1-31
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Appendix J
Estimated Annual Illness Burden
Resulting from Exposure to CSOs and
SSOs at BEACH Survey Beaches
-------
-------
Appendix J
This appendix provides a detailed description of the data and methodology used by EPA to estimate the annual
illness burden associated with exposure to CSO and SSO discharges in recreational waters at state-recognized
beaches. The analysis does not capture all of the likely annual illnesses attributable to CSOs and SSOs at beaches.
EPA believes that CSO and SSO contamination at swimming areas other than those included in this analysis
causes additional illnesses in exposed swimmers. A lack of information on these swimming areas, including
water quality reporting data, precludes developing a more complete estimate of annual human illness frequency
from beach exposure to CSO or SSO contaminants at this time. Moreover, this analysis accounts only for
gastrointestinal illnesses.
J.I National Health Protection Survey of Beaches
EPA's BEACH Survey served as the primary data source for estimating exposure to CSO and SSO discharges to
recreational waters, as noted in Section 6.2.1.
BEACH Survey data include beach-specific information on advisories and closings for 3,067 beaches from 274
federal, state, and local agencies; not all beaches provided data for the four-year period. Beaches included in the
survey are located in 34 states and the U.S. territories of Guam, Puerto Rico, and the U.S. Virgin Islands. These
beaches are primarily marine water beaches, but some freshwater beaches are included. Table J. 1 shows the
number of beaches covered in the BEACH Survey for each state and the number of beaches with and without
pre-emptive actions or monitoring programs.
As shown in Table J.2, California accounts for a significant portion of the total number state-recognized beaches,
closure events, and closure events attributed to CSO and SSO discharges. As a result, California may exert a
disproportionate influence on illness estimates. There are several possible explanations for this, including that
California has a longer swimming and monitoring season and has more rigorous monitoring programs than
many other beaches in the nation, resulting in the discovery of more events than at beaches with less frequent
monitoring and with an abbreviated swimming season. However, EPA lacks the data to make these comparisons at
the time.
Although the BEACH Survey was initiated in 1998 (for the 1997 swim season), only data for the 1999,2000,2001,
and 2002 swimming seasons were used. Data from the 1997 swimming season were excluded from this analysis
because the initial BEACH Survey did not request information from respondents on the source, reason, or cause
of advisories or closings. Further, information from the 1998 swimming season was not used due to an error in
the data recording procedures.
The BEACH Surveys have been modified over time, including changes to the wording of some questions between
1999 and 2002. Furthermore, the rate of participation by beach authorities has changed somewhat with each
BEACH Survey. Nonetheless, EPA believes these differences do not preclude using data from the four most recent
surveys.
EPA recognizes the limitations of the BEACH Survey. Specifically, although the data provided by the respondents
are reviewed by EPA for potential gross errors, the quality and accuracy of the information may vary significantly
with each respondent. In addition, because the BEACH Survey data used in the analysis cover only four years
significant climatological events such as La Nina, which caused a severe drought in southern California during
1999, could have a disproportionate affect on the number of CSOs and SSOs reported in the database. Despite
these shortcomings, EPA believes that the BEACH Survey is the most accurate and comprehensive source of
information on beach contamination and beach authority responses to contamination events. For the purposes
J-1
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Report to Congress on Impacts and Control of CSOs and SSOs
Table J. 1. Number of BEACH Survey Beaches and Type of Program by State
...... „ . ... .. Beaches with no pre-
Number of beaches Beaches with pre-emptive . .
State ••>•-.*-• i 1 »• j/ •» • emptive actions or
in BEACH survey ' actions and/or monitoring .. .
monitoring
Alabama
California
Delaware
Florida
Georgia
Guam
Hawaii
Illinois
Indiana
Iowa
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
New Hampshire
New Jersey
New York
North Carolina
Northern Mariana Islands
Ohio
Pennsylvania
Puerto Rico
Rhode Island
South Carolina
Texas
Vermont
Virgin Islands
Virginia
Washington
Wisconsin
Total
38
1,078
70
962
16
160
288
153
185
102
16
25
200
783
812
74
9
689
906
893
80
3
252
60
47
480
105
65
133
145
56
202
196
9,671
22
803
70
858
16
160
288
153
185
102
16
18
199
748
771
61
9
689
906
837
80
3
252
60
47
480
105
44
132
145
35
184
138
9,002
16
275
0
104
0
0
0
0
0
0
0
7
1
35
41
13
0
0
0
56
0
0
0
0
0
0
0
21
1
0
21
18
58
669
1 The number of total beaches include beaches that reported in any of the four years of the BEACH survey used in this analysis: 1999,
2000,2001,2002; thus,a beach that reported in all four years would be counted four times.
J-2
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Table
J.2. Comparison of California reporting to all other states in the Beach Survey
Appendix J
CA All other states Total Percent
1999 Beach Survey
Number of Beaches
Number of all events
Number of SSO/CSO events
256
1,277
22
1,795
665
102
2,051
1,942
124
1 2.5%
65.8%
17.7%
2000 Beach Survey
Number of Beaches
Number of all events
Number of SSO/CSO events
281
1,545
61
2,073
1,214
148
2,354
2,759
209
1 1 .9%
56.0%
29.2%
2001 Beach Survey
Number of Beaches
Number of all events
Number of SSO/CSO events
272
1,495
268
2,171
2,184
59
2,443
3,679
327
11.1%
40.6%
82.0%
2002 Beach Survey
Number of Beaches
Number of all events
Number of SSO/CSO events
269
1,057
76
2,554
2,157
196
2,823
3,214
272
9.5%
32.9%
27.9%
of this analysis, EPA contacted a limited number of BEACH Survey respondents to collect additional data on
monitoring practices and levels of contamination resulting from SSO events. Other data were obtained from
publicly available sources including beach authority websites, where available.
J.2 Methodology for Counting a CSO or SSO Event
In the BEACH Survey, beach authorities were asked to select the sources of pollution that caused any closures or
advisories. Respondents could choose the following:
•SSO
•CSO
• cso/sso
•POTW
• Septic systems
• Sewer line/blockage/break
• Boat discharge
• Storm water runoff
• Wildlife
• Unknown
• Other (please specify)
For advisories and closings where "SSO" or "sewer line/blockage/break" were identified, the event was classified as
an SSO.
J.3 Categorizing BEACH Survey Beaches
Based on the management practices used to address contamination events, each beach authority and its
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Report to Congress on Impacts and Control ofCSOs and SSOs
corresponding beach(es) were assigned to one of the following categories:
(1) Beaches where the sewer authority reports CSO and SSO events to the beach authority.
(2A) Beaches that preemptively initiate advisories or closures due to wet weather events.
(2B) Beaches where advisories or closure decisions are based on monitoring data or preemptive actions
due to wet weather events.
(3) Beaches where advisory or closure decisions are made based on beach monitoring alone.
(4) Beaches that have reported advisories and closures, but do not have programs described in
Categories 1,2, and 3.
J.4 Calculation of Swimmer Days
The number of swimmers per typical day at beaches where either a closing or advisory action had been
implemented (due to CSOs or SSOs) was estimated by using beach attendance data included in the BEACH
Survey. The BEACH Survey contained the following responses to the question on attendance per day:
•Less than 100
• 100-499
• 500 - 999
• 1,000 - 9,999
•More than 10,000
• Don't know
Respondents provided answers for weekdays, weekend days and holidays, during the summer season, and during
other seasons. Respondents also estimated the length of their swimming season and the percentage of beach
visitors that go into the water.
To calculate the number of swimmers per day on weekdays, on weekend days, for the summer season, and for the
"other season" category, a midpoint value was selected to represent each numeric response range. For example, 50
was assigned for the "less than 100" response, and 5,500 for the "1,000 - 9,999" response. For a beach where the
response was "more than 10,000," EPA assumed an average summer weekday attendance value of 10,000. For a
beach where the response was "don't know", the overall average for beaches who supplied data was used.
The difference between the weekday and weekend values was estimated separately for each year of data. For
example, the BEACH Survey data for the 2002 BEACH Survey indicated that during the summer, the average
weekend attendance levels were on average 62 percent greater than during the weekdays. For the other seasons,
weekend attendance was on average 31 percent greater than the weekday.
A daily summer average was estimated by multiplying the summer weekday value by five, multiplying the summer
weekend value by two and dividing the sum by seven. This procedure was repeated to estimate the daily average
for "other seasons." EPA next calculated a daily average for the year, which consisted of summer and other season
daily averages. EPA estimated the proportion of the values for "summer weekday," "summer weekend," "other
weekday," and "other weekend" based on the length of the season of the beach. If a beach authority reported that
the swim season was six months long, the summer values were counted for six months of the year and the other
values were counted for six months of the year. Similarly, if a beach authority noted that the swim season was only
three months long, summer values were counted for three months of the year, and other values were counted for
nine months of the year.
The percentage of swimmers that enter the water was calculated for each beach, because it was assumed that only
the people who actually go in the water are at risk from CSO- and SSO-related contamination. The percentage
of swimmers was estimated for each beach based on the beach authority's response to the question: "What
percentage of people who use this beach go into the water?" If a beach did not respond to this question the overall
J-4
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Appendix J
average (calculated for all beaches that answered in that survey year) was substituted. Some beaches responded
with a range. In these cases, the midpoint of the range was used. In other cases, beaches responded with either less
than or greater than a number. In these cases, the midpoint between the number provided and 0 or 100 was used
(e.g., if a beach responded greater than 95 percent, then the value used was 97.5). The percent of swimmers was
applied to the attendance for each beach to yield the number of swimmers at each beach.
J.5 Extrapolation Method
This section describes the methods used to extrapolate the exposure estimates for swimmers at BEACH Survey
beaches to other state-recognized beaches that did not participate in the BEACH Survey.
From responses to BEACH Survey questions about visitation and the fraction of visitors who swim, EPA estimated
that 315 million swimmer days per year occur at the BEACH Survey beaches. The BEACH Survey, however,
does not cover all swimming at state-recognized beaches. For example, approximately 13 percent of the beach
authorities to whom the survey was mailed did not respond.
To estimate 1) the number of swimmers at state-recognized beaches not accounted for in the BEACH Survey and
2) the number of swimmers not accounted for at beaches where authorities received a survey and did not respond,
EPA compared selected BEACH Survey attendance data with corresponding state attendance data estimates
reported on the U.S. Life Savers Association and state web sites. A comparison of the Beach Survey data with
the other state attendance data is shown in Table J.3. EPA used an adjustment factor of 1.362 to extrapolate the
Table J.3 Attendance Adjustment Calculations
State Estimated Attendance in BEACH Total Attendance Including
Survey Alternate Sources
California
Delaware
Hawaii
Illinois
Maryland
Total
Adjustment factor
143,283,136
2,479,627
9,462,739
5,399,233
3,353,142
163,977,877
171,146,608
6,000,000
17,285,810
24,885,1 97
4,000,000
223,317,615
1.362
number of swimmer days from the BEACH Survey beaches to all state-recognized beaches in the United States.
EPA applied an approach based on attendance to estimate the fraction of all beach swimmer days represented by
BEACH Survey respondents. The Agency did not have sufficient data to support the assumption that visitation
and swimmer days are proportional to mileage of beaches. EPA believes that heavily-used beaches are more likely
to be surveyed by and respond to the BEACH Survey than are lightly-attended beaches. EPA also assumes that
BEACH Survey beaches likely account for a substantially larger fraction of total beach visitation than the fraction
of total beach mileage accounted for by these beaches. Using the attendance-based approach, EPA estimated
that BEACH Survey beaches account for 73 percent of total national visitation and swimmer days at all state-
recognized beaches.
This approach resulted in the following estimated distribution of the estimated 429 million days per year of
outdoor non-pool swimming:
• 315 million swimmer days at BEACH Survey beaches
• 114 million swimmer days at other formal beaches that either were not sent or did not respond to the
BEACH Survey
J-5
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Report to Congress on Impacts and Control ofCSOs and SSOs
These swimmer days are distributed among categories as shown in Table J.4.
Table J.4 Number of Swimmer Days Per Year, by Category
Number of Category 1 Category 2A Category 2B Category 3 Category 4 Total
Swimmers/Year
BEACH Survey
beaches
Beaches not in
Survey
Total
1 35,049,677
48,871,303
48,871,303
3,674,342
1,319,658
1,319,658
41,754,509
15,109,975
15,109,975
114,619,121
41,477,965
1 56,097,086
19,763,032
7,151,776
26,914,808
314,860,682
1 1 3,940,677
428,801,359
J.6 Exposure/Noncompliance Rates
It is important to note that each jurisdiction has its own definition of an advisory. EPA defines an advisory as "a
recommendation to the public to avoid swimming in water that has exceeded applicable water quality standards
to reduce the potential of contracting a swimming related illness." Although each jurisdiction's definition may
vary, most authorities use an advisory to recommend that visitors not swim in the water. Closures, on the other
hand, usually require that visitors do not enter the water or beach area. The degree to which a closure is enforced,
however, can vary widely.
Different jurisdictions also have different policies regarding when they issue a closure or an advisory. South
Carolina, for example, issues advisories only and does not issue closures. California generally issues an advisory
on a preemptive basis when there is heavy rain; posts a beach warning when monitoring indicates a standard
is exceeded, but there is no known source of human sewage; and closes a beach when there is a CSO, SSO, or
repeated exceedances of standards. The State of New Jersey issues closures only. And, in many states, individual
communities have policies on advisories and closures that can differ from the state's policy regarding state-owned
beaches.
For this analysis, EPA found it was not feasible to standardize the BEACH Survey data and adjust for differences
in how jurisdictions define and use advisories and closures. Instead, EPA aggregated advisories and closures and
refers to them collectively as "actions." Among the "actions" taken by beach authorities in response to CSO or SSO
events, 63 percent were denoted as closures and 37 percent were denoted as advisories.
Effectiveness of actions was estimated by requesting information on the actual effectiveness of beach closures
and advisories in preventing swimming from several local lifeguard offices. There was consensus that closures are
typically well enforced and effective in preventing swimming. Based on this input, EPA assumes that 95 percent
of potential swimmers at a closed beach would comply. The effectiveness of advisories estimate was based on
information in the report, Coastal Beach Water Quality and Public Health: Preliminary Steps Toward Improving
Public Notification in Wisconsin Under the Federal Beach Act (Vail, 2002). It reports results from a social survey
conducted at Wisconsin's public beaches in 2002, in which survey respondents were shown a sign stating "Alert,
Elevated Bacteria Levels, Swim at your own Risk." The survey respondents were asked, "If you saw this sign posted
at this beach, would you swim here?" and could answer either "yes," "no," or "don't know." Results were obtained
for several different counties in Wisconsin. For this analysis, EPA weighted the responses by population and used
the response rate for "no" as the lower bound of compliance; the upper bound was calculated by adding percent
"no" and "don't know". For example, in Door County, 6 percent of the respondents answered "yes," 9 percent
J-6
-------
Appendix J
Table. J.5 Calculations for Advisory Compliance Rates
County Lower Bound Upper Bound Population* Percent of Population
Kenosha
Racine
Milwaukee
Ozaukee
Sheboygan
Manitowac
Kewaunee
Door County
Iron
Ashland
Bayfield
Douglas
Weighted
Average
41
27
9
9
36.42
95.5
73
94
72
90.33
1 56,209
1 92,284
933,221
84,772
113,376
82,065
20,455
28,402
6,727
16,561
15,114
44,093
1,693,369
9.22
11.36
55.11
5.01
6.70
4.85
1.21
1.68
0.40
0.98
0.89
2.60
* Population estimates obtained from U.S.Census 2003.
answered "no," and 85 percent responded "don't know." The upper bound of compliance was calculated by adding
the response rate for no (9 percent) and don't know (85 percent) to yield 94 percent, and the lower bound of
compliance only accounts for the "no" responses (9 percent). Survey results and populations from 12 counties are
shown in Table J.5.
In estimating the overall effectiveness of actions, EPA developed a weighted average of the effectiveness of closures
(95 percent effective) and advisories (36 to 90 percent effective), weighted by the proportion of CSO- or SSO-
caused actions in the baseline that are closures (63 percent) and advisories (37 percent). This results in an estimate
that 73 to 93 percent of potential swimmers, on average, will not swim at a beach when the beach is under a CSO-
or SSO-related action. Conversely, 7 to 27 percent would swim at a beach when a beach is under a CSO- or SSO-
related action.
J.7 Monitoring Data Analysis
Figure J. 1 presents a timeline that shows the relevant events in detecting and responding to beach contamination
from a CSO or SSO discharge and the duration between these events. The timeline is portrayed for instances in
which contamination from a CSO or SSO is detected through monitoring at the beach.
The monitoring data from the beach authorities were analyzed to determine approximately when the
contamination was discovered, when the existence of the contamination was confirmed by analysis of an
additional sample by a beach authority, when the beach authority issued the action, and the period during which
the action remained in effect. The results of this analysis are summarized, by category, on the next page and are
shown in Table J.6.
Category 1 Beaches with preemptive programs close beaches upon notification of CSO or SSO discharges.
It is assumed that the beach is closed prior to contamination and lasts until contamination ends. To
calculate exposure duration, duration data from the 2001 and 2002 BEACH Survey (end date subtracted
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Report to Congress on Impacts and Control ofCSOs and SSOs
Figure J.I Timeline for Response Activities to CSO and SSO Discharges
Contamination
CSO/SSO begins at the Detection of
occurs beach contamination Confirmation
Beach
posted
Contamination
ends
yi
y4
x = The length of time that contamination from the CSO or SSO exists at the beach.
yi =The period between the onset of contamination at the beach and when it was detected.
y2 = The period between the detection of contamination and its confirmation by the beach authority.
y3 =The period between confirmation and action (e.g., beach posting,closure, public notification).
y4 = The period during which the action remains in effect.
from start date) were averaged for all Category 1 beaches. The average length of exposure duration was 5.1
days.
Category 2A The preemptive programs for precipitation events (where beaches automatically close or
post an advisory due to a precipitation event) prevent the full duration exposure to CSOs and wet weather
SSOs, but not dry weather SSOs. Because there is no monitoring or other means to detect dry weather
SSOs, it was assumed that exposure to these SSOs occurs. The estimated exposure duration for these
events is 2.1 days.
Category 2B Similar to Category 2A, preemptive programs for precipitation events eliminate exposure due
to wet weather CSOs and SSOs. Some percent of dry weather SSOs would be detected and actions would
be taken; however, some exposure occurs due to the delay from monitoring. For the purposes of this
analysis, EPA assumed that the percentage of SSO events that were dry weather and that were wet weather
were the same as the percentage of such events reported in the BEACH Survey. That is 34 percent of the
events in Category 2B occurred during dry weather and 66 percent were wet weather related. Exposure to
contamination due to dry weather events was estimated to last 8.7 days, and exposure during wet weather
contamination events was estimated to last 4.5 days.
Category 3 CSOs and SSOs at these beaches are acted upon once monitoring results confirm
contamination, and therefore exposure is avoided only during the period of closure. Exposure during the
actions is 4.5 days and exposure during the lag period is 4.2 days, for a total exposure period of 8.7 days.
J-8
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Table J.6. Duration Calculations by Category
Appendix J
Category
Time Periods
Y1
NA
NA
2.56
2.56
NA
Explanation
For beaches for which there were monitoring data
(categories 2b and 3), the value was calculated
by subtracting the date of the first contaminated
sample from the date of the last clean sample and
dividing by 2.
Y2
NA
NA
1.00
1.00
NA
For beaches for which there were monitoring data
(categories 2b and 3), the value was calculated by
subtracting the date of confirmation from the date
of the first contaminated sample.
Y3
NA
NA
0.68
0.68
NA
For beaches for which there were monitoring data
(categories 2b and 3), the value was calculated by
subtracting the start date of the action from the
date of confirmation.
For beaches for which there were monitoring data
(categories 2b and 3), the value was calculated by
subtracting midpoint between the end date as
reported in the beach report and the last sample
Y4 5.13 2.1 4.45 4.45 10.07 showing contamination from the start date of
the action. For beaches for which there was no
monitoring data (Categories 1,2a,and 4), the end
date was subtracted from the start date reported in
the beach survey.
TOTAL
5.15
2.1
8.69
8.69
10.07 Calculated by adding Y1-Y4
Category 4 Although there were no reported mechanisms in place to detect CSOs and SSOs for these
beaches in the BEACH Survey, some of these beaches reported advisories and closings caused by CSOs or
SSOs. EPA calculated the duration reported from these beaches to be 10 days.
EPA combined information on the number of baseline CSO- and SSO-related contamination events documented
in the BEACH Survey, the duration of events and days of exposure, and the number of swimmer-days, to estimate
the number of swimmer-days of exposure to CSOs and SSOs that would occur at the beaches included in this
analysis. The results of this analysis are summarized in Table J.7.
J-9
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Report to Congress on Impacts and Control ofCSOs and SSOs
Table J.7 Calculations for Exposed Swimmer-Days
Category
^^^^^^^^^^^^^^^B
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ro
Q
OJ
1/1
u
OJ
CO
rs
o
o
rs
01
u
c
ro
"o.
E
o
u
c
o
c
01
c
T3
OJ
VI
O
Q.
X
LLJ
C
t~i
Exposure before detectii
Number of beaches
Average number of beaches per year
Number of SSO and CSO events
acted upon in survey
Number of events per year, per
beach
Number of swimmer days/year for
beaches
Days of exposure during
noncompliance (per event)
Number of such events per year, per
beach
Number of days of exposure during
non-compliance
Percent of year
Number of swimmer days exposed
(7-27% of swimmers do not comply)
Days of exposure before detection
Number of such events per beach
Number of days of exposure per year
per beach
Percent of year
Number of swimmer days (1 00
percent swimmers are exposed)
Total number of swimmer days occurring
during the contamination period
I^M
3,907
977
118
0.121
1 83,920,980
5.13
0.121
0.622
0.17%
21,068-
83,552
0
0
0
NA
0
21,068-
83,552
E^m
91
23
5
0.209
5,004,000
2.10
0.209
0.438
0.12%
404-
1,604
0
0
0
NA
0
404-
1,604
2B
985
246
14
0.055
56,864,485
0.055
0.244
0.07%
2,555-
10,133
4.25
0.019
0.079
0.022%
12,329
14,884-
22,462
3
4,020
1,005
77
0.076
156,097,056
0.076
0.339
0.09%
9,738-
38,620
4.25
0.076
0.323
0.089%
138,209
147,948-
176,830
4
668
167
20
0.117
26,914,808
10.07
0.117
1.175
0.32%
5,830-
23,122
0
0
0
NA
0
5,830-
23,122
Total
9,671
2,418
234
428,801,329
—
-
39,596-
157,030
~
150,538
190,135-
307,568
The first five rows of Table J.7 present information from the 1999-2002 BEACH Surveys. On average, 153 CSO-
and SSO-related closure/advisory actions were reported in the BEACH Survey at these beaches between 1999 and
2002. The number of swimmer days includes swimmer days at state-recognized beaches not in the BEACH Survey,
as described in Section J.5.
The middle section of the table estimates the level of exposure that occurs when non-compliant swimmers
are exposed to CSO and SSO contamination. Multiplying this amount of exposure prevention per event by
the frequency of such events gives an estimate for the average number of days of exposure per beach per year
occurring for noncompliant swimmers. The number of exposed days is then divided by 365 to calculate the
percent of the year when contamination is present at a beach. Next, the percent of the year is multiplied by the
number of swimmer days and by 7 percent and 27 percent (to account for the range of noncompliance exposure
rates) to estimate the total number of swimmer days of exposure to CSO and SSOs during closures and advisories.
J-10
-------
Appendix J
The third section of Table J.7 (exposure before detection) estimates the days of exposure occurring during CSO
and SSO contamination events before they are detected. In this case, exposure occurs only during the lag time
between actual contamination and when the action begins at Category 2B and 3 beaches. Again, the amount
of exposure occurring per event is multiplied by the frequency with which such events occur, to estimate the
average number of days of exposure per beach per year occurring during the lag-time between contamination and
detection. The number of days is divided by 365 to calculate the percent of the year contamination is present at
these beaches. This percentage is multiplied by the number of swimmer days to estimate the number of swimmer
days of exposure to CSOs and SSOs before the advisories and closings are in effect.
The last row of the table presents the number of exposed swimmer days for the two different scenarios of exposure.
J.8 SSO Events Excluded From Exposure Duration Calculations
Several SSO actions were removed from the exposure duration analysis because they were determined to be non-
representative of typical SSO events. Actions were considered to be non-representative of typical SSO events when:
• Action durations were greater than 100 days for a single event.
• Survey entries were found to be erroneous, based on information supplied by the beach authorities or
based on internal quality control checks performed by technical reviewers.
Action durations greater than 100 days for a single event were removed from the analysis or adjusted when
appropriate, because EPA assumed that such extended SSO contamination likely represented a continuous SSO
problem that was well known, and therefore human exposure is less likely. Additional actions were removed from
Categories 1 and 2B calculations. By definition, beach actions issued for these categories were issued preemptively.
However, closer review of 2001 BEACH Survey responses indicated that several actions for these categories had
been issued based on monitoring data alone. The actions in Categories 1 and 2B that were based on monitoring
data alone were not included in these category calculations. In addition, these data were not used in any other
duration categories. All of the actions (four in total) were removed from Category 2B because they were issued
based on monitoring data alone; therefore, no duration estimates could be calculated for this category based on
those four actions.
J.9 Pathogen Concentrations
EPA estimated the average level of pathogens at beaches during closures attributed to CSO and SSO events
and through analysis of monitoring data obtained from the states and reported in the 2001 and 2002 BEACH
Survey. EPA obtained additional monitoring data from relevant state or county websites and by contacting beach
authorities. EPA estimated the in-water concentration during an event by averaging monitoring data observations
obtained during the event including: the first monitoring result indicating exceedance of the bacteria standard and
the presence of contamination, and all subsequent monitoring results until the first monitoring result indicating
that bacteria concentrations had fallen to an acceptable level. The monitoring data indicated similar, highly variable
bacteria concentrations for both CSO- and SSO-contaminated recreational waters and were therefore averaged.
• For salt water closures/advisories, data were obtained for 26 actions. The average enterococci concentration
during these events was 532/100 mL.
• For freshwater closures/advisories, data were obtained for 29 actions. This E. coli concentration was 695/
100 mL.
To account for bacteria levels present at times when SSO and CSO events are not occurring, EPA estimated
background levels. This was accomplished by averaging concentration levels from the last monitoring result
not below the bacteria standard preceding a contamination event at each beach for which there were data. The
monitoring data showed similar, highly variable bacteria concentrations for both CSO- and SSO-contaminated
J-11
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Report to Congress on Impacts and Control ofCSOs and SSOs
recreational waters and were therefore averaged.
• The average background enterococci concentration was 12/100 mL
• For freshwater the background E. coli concentration was 71/100 mL
J.10 Dose Response Equations
The following dose-response functions derived by Cabelli (1983) and Dufour (EPA 1984) were used by EPA
to relate highly-credible gastrointestinal illness (HCGI) symptoms among swimmers to the concentrations of
enterococci (for marine water and for freshwater) or E. coli (for freshwater only):
For marine water:
HCGI symptoms/1000 swimmers = 0.2 + 12.17 log(mean enterococci/100 mL)
For freshwater:
HCGI symptoms/1000 swimmers = -11.74 + 9.4 log(mean E. coli/100 mL)
These equations derive from epidemiological studies sponsored by EPA at several beach locations in the late 1970s
and early 1980s, and provide the basis for EPA's current water quality criteria for recreational waters. EPA's marine
water quality criterion of 35 enterococci per 100 mL, for example, was derived by solving the first equation for
the water quality that would yield the traditionally accepted illness rate of 19 cases per 1000 swimmers. Several of
Cabelli's and Dufour's findings are notable:
• The clearest statistical relationships between water quality and swimmer illness rates were found for
gastrointestinal illness. The statistical relationships were even more definitive when only "highly credible"
gastrointestinal symptoms were considered, in contrast to all gastrointestinal symptoms.
• Enterococci (marine water and freshwater) and E. coli (freshwater) were found to be the best indicator
parameters. They correlated with swimmer illness rates more closely than did other possible indicator
parameters (e.g., fecal coliform).
Despite EPA's adoption of the Cabelli/Dufour dose-response functions as the basis for recreational water quality
criteria, a great deal of uncertainty is associated with the number of illnesses predicted by these functions, as
discussed above. EPA believes most other studies generally support the Cabelli/Dufour conclusion that enterococci
and E. coli are the best indicators (EPA 1984). A comprehensive recent review of epidemiological studies on health
effects from exposure to recreational water conclude similarly that enterococci/fecal streptococci for both marine
and freshwater, and E. coli for freshwater, correlate best with health outcomes (Pruss 1998).
EPA's Office of Research and Development recently reviewed the Cabelli/Dufour studies and the other swimmer
illness studies conducted since 1984, when the last of Cabelli/Dufour's studies were published. The review
concluded:
In examining the relationships between water quality and swimming-associated gastrointestinal
illness, the epidemiological studies conducted since 1984 offer no new or unique principles that
significantly affect the current water quality criteria EPA recommends for protecting and maintaining
recreational uses of marine and freshwaters. Many of the studies have, in fact, confirmed and
validated the findings of EPA's studies. Thus, EPA has no new scientific information or data justifying
a revision of the Agency's recommended 1986 water quality criteria for bacteria at this time (EPA
2002).
J-12
-------
Appendix J
In light of these findings, EPA concluded that Cabelli/Dufour remained the most reliable set of dose-response functions
available to estimate swimmer illness rates in the United States.
Cabelli and Dufour found a statistically significant relationship between indicator bacteria density and gastrointestinal
symptoms for some beaches. However, they found a stronger statistical relationship between indicator bacteria density
and HCGI symptoms, and decided therefore to express their preferred dose-response relationship in terms of HCGI
symptoms rather than total gastrointestinal symptoms. The implication for this analysis is that the Cabelli/Dufour dose-
response relationships may understate by a factor of two to four the total number of gastrointestinal cases that are likely
occurring. This factor may result in EPA substantially underestimating the number of illnesses resulting from exposure
to beach water contaminated by CSO and SSO discharges.
J.I 1 Illness Calculations and Results
The number of HCGI illnesses resulting from exposure to beach water contaminated by CSOs and SSOs was estimated
by combining information on the number of exposed swimmer-days, the concentration of indicator bacteria to which
swimmers are exposed, and the Cabelli/Dufour dose-response functions for marine and freshwaters. Table J.8 shows how
the number of illnesses was calculated from the number of person days exposed to beach water contaminated by CSO
and SSO discharges at beaches included in this analysis.
Table J.8 Derivation of Number of HGCI Cases
Steps
Person Days of Exposure
Allocation of Exposure
Days
Person Days of
Exposure
Pathogen Level
During Contamination
Rate of HCGI Cases
Background Pathogen
Level
Rate of HCGI Cases
Illness Rate for
Contamination Events
- Background Levels
Number of Primary
HCGI Cases
Water Type
(per dose-response functions)
Percent in marine waters
Percent in freshwaters
In marine waters
In freshwaters
Marine waters (EN/100 ml)
Freshwaters (E. coli/1 00 ml)
Marine waters (per 1,000 swimmers)
Freshwaters (per 1,000 swimmers)
Marine waters (EN/100 ml)
Freshwaters (E. coli/1 00 ml)
Marine waters (per 1,000 swimmers)
Freshwaters (per 1,000 swimmers)
Marine waters (per 1,000 swimmers)
Freshwaters (per 1,000 swimmers)
In marine waters
In freshwaters
Total estimated primary HCGI occuring due to human
exposure to SSO and CSO contamination
1
21,068-
83,552
83
17
1 7,487-
69,348
3,582-
14,204
532
695
33
15
12
71
13
6
20
9
350-
1,387
32-128
382-
1,515
2A
404-
1,604
83
17
336-
1,331
69-
273
532
695
33
15
12
71
13
6
20
9
7-
27
1-2
8-
29
Category
2B 3
1 4,884-
22,462
83
17
1 2,534-
1 8,643
2,530-
3,818
532
695
33
15
12
71
13
6
20
9
247-
373
23-34
270-
407
147,948-
176,830
83
17
122,797-
146,769
25,151-
30,061
532
695
33
15
12
71
13
6
20
9
2,456-
2,935
226-271
2,682-
3,206
4
5,830-
23,122
83
17
4,839-
19,191
991-
3,931
532
695
33
15
12
71
13
6
20
9
97-
384
9-35
106-
419
Total
190,135-
307,568
83
17
157,813-
255,282
32,323-
52,287
532
695
33
15
12
71
13
6
20
9
3,157-
5,106
291-470
3,448-
5,576
J-13
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Report to Congress on Impacts and Control ofCSOs and SSOs
References
Cabelli, V.J. et al. 1983. A marine recreational water quality criterion consistent with indicator concepts and risk
analysis. Journal of Water Pollution Control Federation 55(10):1306-1314.
EPA. 1984. Office of Research and Development. Health Effects Criteria for Fresh Recreational Waters. EPA 600/1-
84-004.
May, H., and J. Burger. 1996. Fishing in a polluted estuary: fishing behavior, fish consumption, and potential risk.
RiskAnalysis 16(4):459-471.
National Sporting Goods Association (NSGA).1992. Sports participation in 1990, Series I and II.
Priiss, A. 1998. Review of Epidemiological Studies on Health Effects From Exposure to Recreational Water.
International Journal of Epidemiology 27:1-9.
US DOC, Census (U.S. Department of Commerce, Bureau of the Census). 2004. State and County QuickFacts.
Retrieved July 28,2004. http://www.census.gov
Vail, B. J. 2002. Coastal Beach Water Quality and Public Health: Preliminary Steps Toward Improving Public
Notification in Wisconsin Under the Federal BEACH Act. Wisconsin Department of Natural Resources.
J-14
-------
Appendix K
Summary of Enforcement Actions
K.1 Federal CSO Judicial Orders
K.2 Federal SSO Judicial Orders
K.3 Federal CSO Administrative Orders
K.4 Federal SSO Administrative Orders
K.5 Federal CSO Administrative Penalty Orders
K.6 Federal SSO Administrative Penalty Orders
K.7 State CSO Judical Orders
K.8 State SSO Judicial Orders
K.9 State CSO Administrative Orders
K.1 OState SSO Administrative Orders
K.11 State CSO Administrative Penalty Orders
K.12 State SSO Administrative Penalty Orders
-------
-------
Appendix K
K.1 Federal CSO Judicial Orders
Region State Case Name/City Name Effective Date
1
MA Boston Harbor (MWRA) 1987
Description
MWRA has completed four hydraulic relief projects including,
CAM005, BOS017, Chelsea Trunk, and Chelsea Branch. They have
completed CSO facility upgrades at Cottage Farm, Prison Point,
Commercial Point, Fox Point and Summerville-Marginal. They have
completed upgrades to the floatables removal facility and have
closed outfalls. Under construction are the East Boston Branch
Sewer relief and Union Park Detention/Treatment facility. Sewer
separation is proceeding in South Dorchester, Stony Brook and
Neponset River. Still in the design phase are Fort Point Channel
Storage, the BOS019 storage conduit and parts of the East Boston
Branch Sewer relief and, the South Dorchester and Stony Brook
separation projects.
MA City of Lowell
11/10/88; The Consent Decree required that the City complete construction of
Amended the Southwest Bank Interceptor Project and eliminate all discharges
06/29/01 from outfalls 001 and 003 by 12/15/88. It further required that the
City complete construction of the Northwest Bank Interceptor
Project, eliminate all discharges from outfalls 005 and 006, and
complete construction of Storm Water Diversion Structure Number
Two by 09/01/88. The City was required to eliminate all dry weather
discharges from its West Street Pump Station by 01/15/89 and also
eliminate discharges from outfall 004 by 04/15/89. Finally, they were
required to complete construction for rehabilitation of Marginal
Street Interceptor and eliminate all discharges from outfall 032 by
01/15/90. The City was required to submit a completed Combined
Sewer Overflow (CSO) Facilities Plan to EPA and the Department of
Environmental Quality Engineering of the Commonwealth of
Massachusetts (DEQE) which would address further CSO
abatement.
MA City of New Bedford
12/07/87; The Consent Decree required the City to prepare and submit a CSO
Amended - Facilities Plan by 07/01/89. The Plan identified all of the projects
4/28/95 necessary to meet permit requirements and CSO discharge
requirements. The City was required to construct whatever projects
necessary to eliminate dry weather discharges from CSO outfalls by
03/01/90.
MA
MA
Gloucester
Lynn Water and Sewer
Commission
11/30/88
11/02/89;
Amended
11/15/94;
Amended
06/29/01
The Order addressed noncompliance by failing to complete a CSO
study and treatment plan.
The Order required that by 12/31/03, the Commission would
complete construction of the Summer Street Sewer Separation
Project and complete 100% of the sewer separation for outfall 006
thereby eliminating discharges of combined sewage to outfall 006.
The Order also required that by 12/31/06, the Commission would
complete the sewer separation for outfall 005 eliminating discharges
of combined sewage to outfall 005. Also, by 12/31/09, the
Commission would complete the sewer separation for outfall 004
eliminating discharges of combined sewage to outfall 004.
MA Swampscott
05/05/88 The Order required the completion of a CSO analysis and
development of a schedule for construction of CSO facilities.
K-1
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
Region
1
1
1
1
2
2
2
2
3
State
ME
ME
ME
NH
NJ
NY
NY
NY
MD
Case Name/City Name
City of Bangor
City of Bangor
City of South Portland
City of Portsmouth
North Bergen Township
Niagara Falls
Poughkeepsie
Utica
City of Baltimore
Effective Date
04/09/91 ;
Modified-
06/28/91
6/30/87;
Amended
12/01/87
04/16/92;
Amended-
08/18/94
No date
provided
No date
provided
03/13/87
03/31/88
06/22/77
09/30/02
Description 1
The Order required a CSO facility's plan and CSO abatement
projects implementation.
This Order addressed certain NPDES permit violations.
This Order required a Publicly Owned Treatment Work (POTW)
upgrade and a CSO abatement program for NPDES permit
compliance.
This Order required the implementation of a Long-Term Control
Plan (LTCP).
This Order addressed the failure to meet the construction schedule
for CSO abatement.
This Order required the City to eliminate all dry weather overflows
and submit final plans for repairs necessary to the combined sewer
system (CSS).
This Order required the City to eliminate all dry weather overflows.
This Order required the City to eliminate dry weather overflows and
conduct a Sewer System Evaluation Study (SSES).
The Consent Decree required the City to separate the CSS and
eliminate all CSO structures from the Warbrook neighborhood by
06/30/02 and in the Forest Park neighborhood by 06/30/05. This
represented elimination of all CSOs in Baltimore.
GA City of Atlanta
GA City of Atlanta
GA City of Atlanta
07/13/98 The Consent Decree required Atlanta to perform an evaluation of
their existing CSO control facilities, perform studies and testing of
their CSS and receiving waters and prepare a remedial measures
report which will evaluate appropriate alternatives for CSO control.
The City was required to perform various other studies to evaluate
the efficacy of previous CSO control efforts. The Consent Decree
required that the City prepare CSO Management, Operation, and
Maintenance Plans by 12/01/98.
09/24/98 This Order addressed the nonattainment of water quality standards
resulting from CSOs and it required an evaluation of CSO
discharges and remedial action plan. All construction will be
complete by 07/11/14.
07/29/99 This Order required the City to complete construction for the 10th
Ward Trunk Sewer Improvements (Plan 6) by 07/31/00, complete
construction for the Fairmont/Glidden CSO Separation by 09/30/01,
complete construction for the Phase III Relief Sewer by 08/31/02,
complete construction for the Veterans Hospital Trunk Sewer
Improvements by 11/30/02, complete construction for the Peachtree
Interceptor Relief Sewer by 12/31/02, complete construction for the
Pine Meadows Sewer Improvements by 01/31/03, and complete
construction for the North Fork Peachtree Creek Relief Sewer and
Nancy Creek Sewer System Rehabilitation; the 10th Ward Trunk
Sewer Improvements (Part 1-5); the South Fork Peachtree Creek
Trunk Relief Sewer; and the Indian Creek Trunk Relief Sewer by
02/28/03.
K-2
-------
Appendix K
Region State Case Name/City Name Effective Date
5 IL Metropolis
5 IL Paris
5 IL Rock Island WWTP
5 IN Anderson
5 IN City of Bonnville
IN
Hammond
No date
provided
No date
provided
08/21/03
07/18/02
04/16/87;
Amended
08/13/01
04/23/99
Description
The Consent Decree required correction of the CSO overflow
structure.
The Order addressed NPDES permit violations, resulting in CSO
separation, testing, and first flush treatment.
The Order addressed permit violations. Rock Island was required to
prepare and submit a LTCP. A penalty of $150,000 was assessed.
The Consent Decree required that by 12/31/09, they will complete
construction for all improvements.
The 1987 Consent Decree required the City to adequately maintain
the CSS and improve plant operations.
The Consent Decree required Hammond to maximize combined
sewage flow through the collection system and treatment plant and
implement their LTCP. They were directed to construct facilities as
needed to eliminate three of their CSOs, including but not limited to:
a storage reservoir, pump station improvements, sewer separation,
sewer interceptors, and sewer interceptor improvements by
05/01/09.
IN
Madison
5 Ml Menominee
5 Ml Wayne County
OH
OH
OH
Bedford
OH
OH
City of North Olmsted
Port Clinton
No date The Consent Decree required development of a CSO management
provided plan.
04/21/88 The Order addressed unauthorized CSO discharges.
1994 The Order addressed CSOs contributing to public health advisories
against swimming and nutrient loading stimulating plant and algae
growth in downstream water bodies including Lake Erie.
09/30/85
Cincinnati Metropolitan No date
Sewer District provided
City of Akron No date
provided
07/31/91
09/08/99
5 OH Portsmouth
5 OH Toledo
1992
12/19/02
This Order required City to conduct a CSO facility study and
implement a plan for appropriate treatment of CSOs.
This Order addressed unauthorized dry weather discharges from
CSOs.
This Consent Decree addressed CSOs causing violation of effluent
limits and failure to meet schedule for elimination of CSOs.
Under this Order they were required to achieve consistent
compliance with its permit within 40 days of the Order.
This Order required monitoring and scheduled CSO abatement.
Port Clinton was required to submit a plan for permanent CSO
improvement or closure by 11/01/99.
This Order addressed CSOs causing water quality standard
exceedances in the Scioto and Ohio Rivers.
The Toledo Consent Decree addressed both CSO issues and
Sanitary Sewer Overflow (SSO) issues. Regarding CSOs, Toledo
was required to design and construct certain "Phase I" CSO control
measures including: East Side and Bay View Pump Stations
improvements, secondary treatment backup power, a 60 MG
equalization basin, an additional secondary clarifier, and a 185
MGD capacity ballasted flocculation wet weather treatment system.
These "Phase I" projects were estimated to cost $157 million, and
were to be complete within approximately 40-45 months of decree
entry (depending on plan review and approval). Toledo was also
required to develop and implement a LTCP. The LTCP control
measures were to be completed by August 2016.
K-3
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
OH
Wellston
OH Youngstown
10/13/87
03/05/02
Description
This Order addressed CSO discharges due to improper Operation
and Maintenance (O&M) and unpermitted bypasses.
Youngstown was required by the Consent Decree to: eliminate an
outfall in a local park (Outfall 6108) by 05/06; eliminate two small
direct sewage discharges ("Tod & Irving East & West") by 08/03;
develop a LTCP by 01/03; remove accumulated sediment from the
Mill Creek Collector Sewer by 06/02; and implement various short-
term operational (i.e., Nine Minimum Controls (NMCs))
improvements and pump station upgrades/ replacements by 2007.
K-4
-------
Appendix K
K.2 Federal SSO Judicial Orders
Region State Case Name/City Name Effective Date
Description
1 CT Greenwich
1 CT Waterbury
MA Winchendon
Puerto Puerto Rico Aqueduct
Rico and Sewer Authority
(PRASA)
01/15/02
11/21/02
07/29/02
This Consent Decree required that construction be complete by
12/08.
The Consent Decree was issued to prevent future Sanitary Sewer
Overflows (SSOs) from occurring. Multiple construction schedules
were established in the Order and were pending EPA approval.
MD City of Baltimore
This Consent Decree required that construction for the SSO
improvements be complete by 01/04 and construction for the
Publicly Owned Treatment Works (POTW) improvements be
complete by 07/05.
Lodged 03/13/03 This Consent Decree required specific remedial actions at a defined
list of pump stations. PRASA was required to submit the detailed list
of actions to be performed at each station and a proposed schedule
for same, within 90 days of entry date of Consent Decree. All
remedial actions at these stations were to be complete within 32
months of the date of final approval of the list. All pump stations
were to be subject to an Operation and Maintenance (O&M) plan,
which was to be developed by PRASA. A Spill Response and
Cleanup Plan was required to be submitted within 90 days of date of
entry of Consent Decree. The Plan was to be reviewed annually and
updated as necessary.
09/30/02 Remedial actions included: elimination or modification of designated
SSO structures; reporting of SSO events; identification of all SSO
structures, flow monitoring, collection system evaluation and
sewershed planning, Infiltration and Inflow (I/I) evaluation;
elimination of cross connections between sanitary and storm sewers;
peak flow modeling; inspection of all gravity sewers 8-inches and
larger and all force mains, manholes, etc.; evaluation of long-term
capacity; identification and elimination of illegal private connections;
rehabilitation of certain pump stations; inspection of all pump
stations twice daily until SCADA is installed; update of maintenance
information management system; performing pump station
preventive maintenance; updating existing O&M manuals;
implementing a maintenance program for the collection system and
an overall information management system program; inspection of
all valves in the collection system; development of an Emergency
Response Plan; and reporting both orally and in writing any
unauthorized discharges to waters.
PA Borough of Indiana
3 PA Bradford
3 VA Galax
06/17/02 Objectives of the Consent Decree included compliance with final
effluent limits, elimination of bypasses at the treatment plant, and
elimination of SSOs. The remedial action for SSO elimination was to
implement the EPA-approved SSO Response Plan that was
previously submitted. With regard to the other issues, by 07/01/03,
the Borough was supposed to have completed the wastewater
treatment plant expansion projects, including the entire Wastewater
Detention Tank. The Borough was also supposed to complete the
Main Plant Interceptor project by 08/01/03.
04/11/03 This Consent Decree addressed NPDES permit violations and
assessed a $40,000 civil penalty.
01/30/03 This Consent Decree required the City to implement a
Comprehensive Management, Operation and Maintenance (CMOM)
program. All construction was to be complete by 03/03.
K-5
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
AL
Jefferson County
12/15/96
Description
The Consent Decree laid out a three-phase plan. Phase I required
the County to develop a series of planning documents that would
identify the scope, methodologies, time frames, and resources to be
allocated to evaluate the condition and capacity of the collection
system, identify sources of I/I, and develop remedial measures.
Phase II consisted of analyses and reports to determine the extent of
rehabilitative needs and corrective actions necessary. Phase III was
the implementation phase, in which specific improvements were to
be made according to the Capacity Improvement Schedules and the
Performance Improvement Plans developed in Phase II.
AL
Mobile
01/24/02 The Consent Decree required them to develop both Short-Term and
Long-Term Capacity Assurance Programs. They were required to
implement an EPA-approved SSO Reporting, Notification, and
Record Keeping Program and submit a semi-annual report to EPA
analyzing information available through its information management
systems. They were also required to submit and implement Legal
Support Programs, including an ordinance for grease control, as well
as develop and submit a Contingency Plan for Sewer and
Wastewater Treatment Facilities. They also had to submit and
implement the following programs: Scheduled Pump Station
Operation Program, Electrical Maintenance Program, Mechanical
Maintenance Program, Force Main Preventive Maintenance (PM)
Program, Gravity Line PM Program, Scheduled Hydraulic Cleaning
Program, Root Control Program, Unscheduled Maintenance
Program, revised Grease Control Program. A wet weather and dry
weather water quality monitoring program was also required.
FL Miami-Dade
(Second and Final Partial
Consent Decree)
04/95
This Consent Decree required an I/I evaluation and rehabilitation
program; identification of a service area for each pump station;
complete evaluations of 6.96 million feet of sewer lines and
associated manholes; addressing I/I on private property;
identification and elimination of illegal storm sewer connections to
the sanitary sewer; development of a program to identify illegal
storm sewer connections; inspection and, where necessary, repair of
each pump station; repair or other improvements to pump stations
that caused or contributed to SSOs; completion of the installation for
the online remote monitoring equipment; submission of a Short-Term
Collection System Operating Plan and a Long-Term Collection
System Operation Plan; development of and implement a
computerized collection and transmission system model;
development of a program of pump station upgrades and collection
system improvements; implementation of a collection system
maintenance program; development of an inventory management
system; and develop a program to optimize wastewater treatment
efficiency and effectiveness.
GA City of Atlanta
12/20/99 This Consent Decree required that construction for all improvements
be complete by 07/01/14.
K-6
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Appendix K
Region State Case Name/City Name Effective Date
GA City of Atlanta
07/29/99
Description
This Consent Decree required the City to complete construction for
the 10th Ward Trunk Sewer Improvements (Plan 6) by 07/31/00,
complete construction for the Fairmont/Glidden CSO Separation by
09/30/01, complete construction for the Phase III Relief Sewer by
08/31/02, complete construction for the Veterans Hospital Trunk
Sewer Improvements by 11/30/02, complete construction for the
Peachtree Interceptor Relief Sewer by 12/31/02, complete
construction for the Pine Meadows Sewer Improvements by
01/31/03, and complete construction for the North Fork Peachtree
Creek Relief Sewer and the Nancy Creek Sewer System
Rehabilitation, the 10th Ward Trunk Sewer Improvements (Part 1-5),
the South Fork Peachtree Creek Trunk Relief Sewer, and the Indian
Creek Trunk Relief Sewer all by 02/28/03.
4
GA City of Atlanta
GA Dalton
IN New Albany
07/13/98
Lodged
01/18/01;
Entered
03/28/01
06/18/93;
Amended
05/03/02
This Consent Decree addressed violations of its NPDES permits by
discharging untreated wastewater containing raw sewage and
partially treated wastewater into the Chattahoochee and South
Rivers and their tributaries.
This Consent Decree covered SSO, sludge, land application, and
pretreatment. Construction was expected to be complete by 12/03.
This amended Consent Decree required the City to develop a
computerized collection system model, a SSO response plan, and a
capacity assurance plan. They were also required to identify and
remove all l&l sources unless exempted by EPA, perform wet
weather survey and sampling, identify and remove any cross
connections, and remove or separate any combined sewers. The
capacity assurance plan included proposed remedial measures and
a schedule for their design and construction. A comprehensive
preventive maintenance program and a grease control program were
also required to be developed and implemented. All piped overflows
were to be flow metered. Flow volumes and rates of sanitary sewage
input to a flood control pump station were to be estimated and
sampled, and results submitted to EPA. Bypasses at these locations
were to be reported to EPA within 24 hours. Alternative power
sources and lightning protection at pump stations were to be
provided to prevent overflows and the City was required to
demonstrate for one year that all capacity related overflows had
been eliminated.
5 IN South Haven Sewer
Works
5 OH Akron
Lodged 07/17/03 This Consent Decree addressed permit violations.
07/28/95 This Consent Decree required them to have construction complete
for all improvements by 12/31/96.
K-7
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
Description
OH Hamilton County (Interim Lodged 02/15/02 This Consent Decree required Interim Remedial Measures (IRM) to
Partial Consent Decree)
include expenditure of $10-$15 million on an overflow treatment and
storage facility for "SSO 700" and development of an IRM Plan
evaluating system, including cost/performance, design storm
parameters, etc., and schedule for completion by no later than
12/31/07. After its completion, the County was to conduct an
Effectiveness Study of the treatment and storage facility. Permanent
Remedial Measures included a Remedial Plan due 12/31/09, with a
goal of eliminating the "SSO 700" discharge point. The Remedial
Plan was to specify proposed measures, estimated costs, annual
O&M costs and expected performance during various storms. It also
required a Comprehensive SSO Remediation Program to deal with
SSOs in other parts of the system. This included modeling, capacity
assessment, SSO response program, SSO monitoring and reporting
plan, pump station operation program, industrial waste SSO/CSO
management, etc.
OH
Toledo
12/19/02 This Consent Decree addressed NPDES permit violations, including
failure to implement a Long-Term Control Plan (LTCP). They were
required to have construction complete for all improvements by
12/16. This Consent Decree only addressed those that were point
source discharges to waters, referred to as Sanitary Sewer
Discharges (SSDs). Provisions that apply to SSDs include
performing a Sanitary Sewer Evaluation Study (SSES), development
of schedule for construction of sanitary sewer improvements;
elimination of all known points of illegal discharge by 11/01/06;
development of a Separate Sewer System Monitoring and Reporting
Plan; development of an SSD response plan; development of an
Industrial Wastewater Release Minimization Plan to reduce
discharge of industrial pollutants through SSDs; and development of
a Sewer System Management, Operation and Maintenance Plan to
include gravity sewers, force mains, pump stations.
LA City/Parish of East Baton
Rouge
12/23/88; Remedial measures in this Consent Decree included elimination of
Modified cross connections, development of preventive maintenance program
07/23/97 and SSO response plans, reporting unauthorized discharges, and
monitoring environmental results. Also, a collection system remedial
program was to be selected and completed. The components of this
program were to include construction of storage basins and tanks,
construction, modification or elimination of pump stations,
construction of deep underground sewers and construction of
treatment facilities. A treatment facility assessment was to be
performed to evaluate whether improvement or expansion of three
existing plants, or changes in plant O&M, were needed to comply
with NPDES permits and handle future loading.
LA City/Parish of East Baton
Rouge
03/14/02 The environmental benefit of this Consent Decree was that 1.2 billion
gallons will be eliminated annually. A $1.12 million SEP was to be
performed by the City and a penalty of $945,500 was assessed.
K-8
-------
Appendix K
Region State Case Name/City Name Effective Date
LA
New Orleans
04/08/98
Description
This Consent Decree required the Board to operate the fluidized bed
incinerator with the EPA-approved O&M plan, have backup pumps
for the pump stations, have the SCADA installed at all but one of the
pump stations, operate a 24-hour manned central dispatch center,
and certify that most known cross connections have been
permanently sealed. Some cross connections were permitted to be
retained, for these, the Cross Connection Security Plan would be
followed and a physical barrier such as a valve or gate would be
between the storm and sanitary sewers. They were also required to
comply with the EPA-approved Preventive Maintenance Program
and the Sewer Overflow Action Plan, track and report all
unauthorized discharges, undertake a Remedial Action Program
which would include flow monitoring, development of a computerized
model, identification of construction projects, performance of
collection system evaluation studies, and development of a
Remedial Measures Action Plan (RMAP). Additionally, they will
develop a storm sewer monitoring program.
CA San Diego
HI
Honolulu
06/09/97
Judicial ruling as
to liability and
penalties,
settlement and
injunctive relief
05/15/95
This Consent Decree required them to have all construction
complete by 12/07.
This Consent Decree required implementation of the EPA-approved
pretreatment program, and included a requirement to develop
technically based local limits for any pollutants of concern. They
were also required to submit annual goals for reduction of SSOs for
the years 1994 through 1999, and submit a Spill Reduction Action
Plan by 12/31/95. This Plan was to include a Preventive
Maintenance Plan, procedures for conducting grease trap
inspections, evaluation of staffing needs, and equipment inventory.
Interim preventive maintenance activities were also specified,
including inspection and cleaning of at least 300 miles of sewer per
year, semi-annual grease trap inspections, and inspection and
cleaning of SSO hot- spots. Additionally, they were required to
implement a computerized wastewater information and management
system by 12/31/95 and developed an I/I program to prevent wet
weather overflows.
HI
Maui
09/09/99 This Consent Decree required the County to submit a Spill
Reduction Action Plan (SRAP) to include implementation schedules,
a spill response plan, a sewer preventive maintenance plan, a pump
station spill reduction plan, an employee training program, a Fats,
Oil, and Grease (FOG) control program, and a construction spills
prevention plan by 01/01/00. They were also required to update its
information management system to include systematic recording of
collection system O&M activities and information obtained from
sewer inspections and grease interceptor inspections and implement
a Long-Term Sewer Line System Analysis and Rehabilitation Plan. A
long-term treatment plant and pump station plan was required for
rehabilitation, replacement and expansion of these facilities. Both of
these plans have varying schedules depending on area and quarterly
reporting.
K-9
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Report to Congress on the Impacts and Control of CSOs and SSOs
K-10
-------
Appendix K
K.3 Federal CSO Administrative Orders
Region State Case Name/City Name Effective Date
1
MA Chicopee WPCF
06/06/97
Description
This Order required them to complete construction of eliminating
dry weather overflows at CSOs 027 and 037 and to complete river
inflow improvements. Chicipee WPCF has constructed a CSO
related bypass at the WWTP, allowing additional wet weather flow
to receive primary treatment at the WWTP, thereby reducing CSOs.
MA Chicopee WPCF
MA City of Chicopee
MA
MA
MA
City of Fall River
City of Fall River
City of Fall River
1 MA City of Fall River
1 MA City of Fall River
1 MA City of Fall River
1 MA City of Fitchburg
06/03/99 The Order required them to complete construction to eliminate dry
weather overflows at CSO 027 (Front Street), CSO 037 (East Main
Street), and River inflow improvements and to complete the
cleaning of the second siphon at CSO 024 (V).
09/95 This Order required an abatement schedule for CSOs to
Connecticut River.
1987 This Order addressed unauthorized CSO discharges.
1988 This Order addressed unauthorized CSO discharges.
05/05/90 This Order required submittal of a report detailing the causes of the
violations, including recommendations for bringing the discharge
into compliance with the permitted limitations and a schedule for
implementing the recommendations and achieving full compliance.
08/29/91 This second Order required a detailed engineering report
evaluating the City's ability to comply with the NPDES permit
requirements.
05/05/94 This third Order required, among other things, that the City submit a
plan and schedule for bringing its discharge into compliance by
11/01/95.
05/05/97 Under this Order, the City was required to complete construction
and attain operational level of the dechlorination system to comply
with the permits effluent limits for total residual chlorine and
coliform.
08/31/94 This Order required them to submit a scope of work and an
implementation schedule to complete a Long-Term Control Plan
(LTCP).
K-11
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
1 MA City of Fitchburg
1 MA City of Fitchburg
02/2/96;
Amended
07/02/96
12/01/00
Description
This Order required the immediate implementation of the Nine
Minimum Controls (NMCs), submission of a report documenting
NMC implementation by 07/31/96, submission of a draft Long-Term
Control Plan by 04/30/98, submission of a final LTCP by 08/29/98,
and then implementation of the approved LTCP. The City is
proposing separation.
This Order required that the City identify appropriate measures to
prevent all dry weather CSO discharges from the Collection
System. The Order required the City to submit a report that
described those measures and provided a schedule for their
implementation "as soon as possible". The report was to be
submitted within 30 days of receipt of the Order.
1 MA City of Haverhill
1 MA City of Haverhill
08/09/99 This Order addressed CSO discharges in violation of permit
requirements. The Order required the City to complete and submit
to EPA and MADEP a draft LTCP by 08/31/00, and a final LTCP by
01/15/01.
12/17/01, The Order required the City to submit a Final LTCP by 08/02/02.
supercedes The Order also required the City, by 04/01/03, to submit plans and
11/02/01 specifications to EPA for: a parallel force main, measures to
increase the WWTP peak wet weather capacity (through primary
treatment), and primary bypass disinfection. Once approved by
EPA, the City was to implement these measures within 28 months.
The Order also required the City to submit plans for the structural
modifications of Bradford-Side CSOs by 05/03/03, and complete
those modifications within 15 months. The Order also required
submission and implementation of a CS monitoring program.
MA City of Holyoke
1 MA City of Holyoke
12/08/00
04/11/01
1 MA City of Holyoke 09/95
1 MA City of Holyoke WPCF 03/27/97
The Order required the City to complete construction of the Green
Brook Sewer Separation Project, remove Green Brook flow from
the combined sewer system (CSS) and eliminate all dry weather
overflows from CSO discharge points.
The Order required the City to complete construction of Day Brook
detention basin project and complete construction of the upgrade to
the wastewater treatment facility.
Under this Order, they were required to prepare an abatement
schedule for CSOs to Connecticut River.
This Order required the City to: initiate the appropriation of funds
needed to complete the LTCP by 04/15/97; complete the
appropriation of those funds by 05/06/97; submit a SRF application
by 06/01/97; submit to EPA and MADEP a CSO monitoring plan by
08/01/97; begin implementing the CSO monitoring plan by
09/01/97; submit to EPA and MADEP a CSO optimization plan by
10/01/97; complete implementation of the CSO monitoring plan by
06/30/98; complete implementation of the CSO optimization plan by
03/01/99; complete calibration of a computer model of the collection
system by 03/31/99; submit to EPA and MADEP a draft LTCP by
10/01/99; and submit a final LTCP to EPA and MADEP by
04/01/00.
K-12
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Appendix K
Region State Case Name/City Name Effective Date
1
MA City of Taunton
01/29/96
Description
The Order required the City to submit to EPA and to the
Massachusetts Department of Environmental Protection (MADEP)
a revised Scope of Work for conducting long-term improvement
projects addressing Infiltration and Inflow (I/I) reduction, combined
sewer overflow (CSO) abatement, and the Wastewater Facilities
Capital Improvements Plan, all by 02/15/96. The Order also
required the implementation of short-term improvements including:
installation of a tide gate on the Water Street CSO by 03/01/96,
submission of a high flow management plan by 03/15/96, updating
of the sewer mapping system by 05/01/96, and submission of
collection system and WWTP operating budgets by 05/01/96.
MA
City of Worcester
09/18/00 The Order required the City to submit a Scope of Work for
development of a Phase I LTCP within 4 weeks of the Order date.
The Order required submission of the Phase I LTCP within one
year of EPA and MADEP approval of the LTCP SOW. The Phase I
LTCP was to include a SOW for development of a Phase II LTCP.
Submission of the Phase II LTCP was required 12 months following
approval of the Phase I LTCP by EPA and MADEP.
1 MA Gloucester 1989
1 MA Greater Lawrence 06/24/99
Sanitary District, North
Andover
1 MA Massachusetts Water 05/13/96
Resources Authority
^^^^^^ (MWRA)
1 MA Springfield Water and 04/26/02
Sewer Commission,
Springfield
The 1989 Consent Decree required a LTCP development. The
LTCP was received 04/01.
This Order required the District to submit to USEPA and MADEP a
revised NMC report, and to develop and submit to EPA and
MADEP for approval, draft (due 06/31/01) and final (due 12/31/01)
LTCP report.
Under this Order, they were required to plan and implement actions
to attain water quality standards.
This Order required the Commission to: submit a BMP Plan for the
Watershops Pond by 03/31/02; submit a final LTCP to EPA and
MADEP by 03/15/03; and complete construction of the approved
Chicopee River CSO abatement program by 11/15/07.
MA Springfield Water and 09/95
Sewer Commission,
Springfield
MA Springfield Water and 03/21/97
Sewer Commission,
Springfield
This Order required an abatement schedule for CSOs to
Connecticut River.
The Order required the Commission to: secure funding necessary
to develop and implement the LTCP by 04/01/97; submit to EPA
and MADEP a report documenting implementation of the NMCs by
04/15/97; submit to EPA and MADEP a CSO monitoring plan and
LTCP Work Plan by 07/01/97; engage a consultant to develop the
LTCP by 08/15/97; begin implementing the CSO monitoring plan by
03/01/98; complete implementation of the CSO monitoring plan by
06/30/98; complete calibration of a computer model of the collection
system and submit to EPA and MADEP a draft LTCP by 05/31/99;
and submit a final LTCP by 08/31/99.
K-13
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
1 MA Springfield Water and 11/14/00
Sewer Commission,
Springfield
1 MA TownofAgawam 09/21/95
1 MA TownofAgawam 12/30/96
MA Town of Ludlow 09/95
MA Town of Ludlow WTP 12/30/96
MA Town of Palmer 01/06/97
MA Town of South Hadley 09/95
MA Town of South Hadley, 03/14/97
WTP
MA West Springfield
09/01/95
ME Augusta Sanitary District 07/20/97
Description
Under this Order, the Commission was required to begin
construction of interceptor relief conduits and a local storage
conduit for CSO 019 by 06/01/02; complete construction of those
interceptor relief conduits and local storage conduit for CSO 019 by
12/31/03. Additionally, the Order required the Commission to begin
improvements to the York Street Pump Station by 03/01/01; begin
improvements to the Union Street Pump Station by 02/01/02; and,
complete the pump station improvements by 03/01/04. The City
was required to submit a final LTCP by 03/15/02.
Under this Order, the Town was required to submit a Scope of
Work and schedule for CSO facilities planning activities.
Under this Order, the Town was required to submit a report
documenting its implementation of the NMCs by 03/30/97.
Following completion of the then-ongoing Little Canada Sewer
Separation Project, the Town was then required to implement its
existing CSO monitoring plan. Following completion of monitoring,
the Town was then required to either submit a plan for additional
CSO control, or for the sealing of all CSOs.
This Order required an abatement schedule for CSOs to
Connecticut River.
Under this Order, they were required to submit a report on the
implementation of the NMCs as part of controlling discharges from
its CSOs. The Town will implement the CSO monitoring plan.
This Order addressed CSO discharges in violation of permit and a
penalty of $5,000 was assessed.
This Order required an abatement schedule for CSOs to
Connecticut River.
This Order required the Town to: apply for SRF funds by 03/31/97;
complete construction of the Falls Sewer Separation Project by
05/03/99; submit plans and a schedule for the East Side sewer
separation project by 03/14/98 ; and complete construction of the
Mount Holyoke I/I project, the Silver Street catch basin elimination
project, and eliminate CSOs #10 and #14 all by 01/01/01.
This Order addressed CSO discharges in violation of permit. The
Order required a CSO abatement schedule.
This Order required the District to: complete "Phase I" WWTP wet
weather flow capacity improvement projects by 10/31/98; and
complete adjustments to the regulators tributary to CSOs 010, 019,
023, 032, and regulators 029B, 029C, 029D, 029E, 029F, and 029G
by 08/01/95. Where those adjustments and "flow slipping", are
insufficient to control CSOs, the District must complete separation
projects by 06/01/98.
K-14
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Appendix K
Region State Case Name/City Name Effective Date
1 ME Biddeford 04/22/94
1 M E City of South Portland 11/10/97
Description
This Order required a CSO abatement schedule.
Under this Order, the City was required to not bypass secondary
treatment at flows less than 22.9 MOD. Bypassing was to occur in
accordance with a "High Flow Management Plan" approved by
MEDEP. Bypassed flow was to receive the equivalent of at least
primary treatment and be disinfected during the disinfection season.
This requirement was to remain in effect until either: the permit was
modified to incorporate a generic bypass provision; expiration of
that permit; compliance by the blended effluent with secondary
limits; or elimination of the need to bypass as a result of the sewer
separation phase of the CSO abatement project.
ME Lincoln Sanitary District 12/17/98
Under this Order, the District was required to implement the
collection system and wastewater treatment facility (WWTF)
improvements and CSO abatement projects in accordance with the
approved Implementation Schedule. Immediate and continued
compliance with the NMCs was also required. Also under this
Order, the District was required to not bypass secondary treatment
at flows less than 2.8 MOD (instantaneous flow) or 1.07 MOD (daily
average flow). Bypassing was to occur in accordance with a "High
Flow Management Plan" approved by MEDEP. Bypassed flow was
to receive the equivalent of at least primary treatment and be
disinfected during the disinfection season. This requirement was to
remain in effect until either: the permit was modified to incorporate
a generic bypass provision; compliance by the blended effluent with
secondary limits; or elimination of the need to bypass as a result of
sewer separation projects.
ME Sanford Sewerage 07/13/98
District, Town of Sanford
The Order required the District to submit a "Draft CSO Master Plan"
within 180 days of receipt of the order, and further required
completion of the approved Master Plan in accordance with the
schedule included therein. Immediate and continued compliance
with the NMCs was also required.
NH
City of Nashua
04/16/99
1 NH City of Portsmouth 07/11/02
Under this Order, the City was required to implement the
construction of specified combined sewer separation projects, as
well as to implement a yet-to-be-completed Combined Sewer
Separation Plan (due within five years of the Order's effective date.
The City will eliminate all CSOs by 2019. The City was also
required to revise and implement its WWTF High Flow
Management plan.
This Order required the City to submit a LTCP and an updated
NMC plan by 08/01/02. The City was required to submit a
preliminary design report for the CSO measures recommended by
the LTCP by 02/08/03, and advertise for bids for the construction of
a particular project in the vicinity of Outfalls 01OA and 01 OB by
03/03/03 (two of the three CSOs in the City's CS).
K-15
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
1 NH Lebannon WWTP & City
STP
06/06/00
Description
The Order required them to design and construct combined sewer
separation projects to eliminate six CSOs (CSOs 010, 027, 026,
005, 022, and 023) by 12/31/08. Additionally, the City was required
to submit a plan to EPA to eliminate the seventh CSO (CSO 024)
by 12/31/12.
NH Manchester STP 03/08/99 Action was taken to address nonattainment of water quality
standards caused by CSOs. The Order required the City to submit
plans and specifications for WWTP wet weather treatment
modifications within 6 months of the Order's effective date, and to
complete construction of those modifications within 12 months of
plans and specifications approval. Completion of specified CSO
abatement projects ("Phase I" projects) within 10 years of the
Order's effective date, completion of a study of CSO #44 within 5
years of Order issuance, provision of a revised ("Phase II") LTCP
within 11 years of the Order's effective date, and a $5.6 million
supplemental environmental project (SEP) were also required.
NH
Town of Exeter
02/03/97
PA Connellsville Municipal 09/30/02
Authority
The Order required the City to submit a report documenting the
Town's implementation of the NMCs by 04/30/97.
Under this Order, the Authority was required to provide, within 15
days, an explanation of actions taken to comply with the CSO
policy's NMCs requirements and to implement the Authority's
existing NMCs Report. Within 30 days, the Authority was required
to submit a detailed plan and schedule for fully implementing the
NMCs. The order also required the Authority to, within 30 days,
identify the resources needed to properly operate and maintain
collection system, and to describe any actions the Authority was
planning to take to further minimize CSO discharges and water
quality impacts.
PA Export Borough
05/15/97
PA Lower Lackawanna Valley 12/06/01
Sewer Authority (LLVSA)
This Order addressed the Borough's failure to obtain and
implement the requirements in the CSO general permit. This Order
required the Borough to apply to PADEP for a NPDES permit for
CSO discharges.
This Order required the Authority to submit, within 60 days of
receipt of the order, a plan and schedule that identified specific
measures to eliminate dry weather overflows. The Authority was
required to submit, within 60 days, a plan and schedule detailing
how the Authority was expected to fulfill the CSO-related monitoring
requirements in its NPDES permit. The Authority was also required
to submit, within 180 days, a report identifying critical CSO points
and identifying root causes and preventive measures to prevent
and/or minimize the impact of discharges from the critical CSO
points. Within 45 days of each submittal, the Authority was required
to implement that plan.
K-16
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Appendix K
Region State Case Name/City Name Effective Date
PA Pittsburgh Water and
Sewer Authority
PA Scranton
11/20/96
11/27/02
WV City of Marmet
WV City of McMechan
09/04/02
09/30/02
WV Kenova
IL City of Lawrenceville
06/10/03
09/30/02
IL City of Rock Island
IN Bluffton POTW
IN Bluffton Utilities
IN Fort Wayne
OH Columbus WWTP
OH Port Clinton
02/13/98
06/06/00
03/19/98
1995 and 1996
07/17/98
1995
Description
This Order addressed the Authority's failure to obtain and
implement the requirements in the CSO general permit. This Order
required the Authority to apply to PADEP for a NPDES permit for
CSO discharges.
Under this Order, they were required to submit appropriate
documentation demonstrating implementation of and compliance
with the 1998 NMCs Plan. They were also required to complete and
submit to the Pennsylvania Department of Environmental Protection
(PADEP) and EPA a revised LTCP and a schedule for
implementation.
The Order required the City to submit within 60 days: a plan and
schedule for complying with the water quality monitoring
requirements of its NPDES permit, and a plan and schedule for
reducing I/I levels in the collection system.
The Order required the City to submit within 60 days plans and
schedules for complying with: the water quality monitoring
requirements of its NPDES permit, the collection system O&M
provisions of its NPDES permit, the pollution prevention
requirements of its NPDES permit, and the CSO monitoring and
characterization requirements of its NPDES permit. The Order
required implementation of each of these plans within 90 days of
the issuance of the order.
No additional information provided.
The Order required City to construct and operate an oil collection
device at the storm sewer outfall to ensure the discharge of oil and
pollutants is minimized. Upon completion and after proper operation
of the new replacement sewer, the City had the option of removing
the oil collection device. The City was also required to submit a
New Sewer Work Plan to EPA by 10/30/02, and shall complete
construction by 10/30/03.
This Order addressed CSOs to environmentally sensitive areas and
failure to implement the NMCs. The Order also required plant and
sewer improvements to reduce CSOs.
The Order addressed failure to submit CSO plan. An Administrative
penalty order required a SEP and assessed a $60,000 penalty.
The Order addressed permit violations.
The Order required them to identify all CSO outfalls and to submit a
sanitary sewer overflow (SSO) elimination plan and implement the
SSO elimination plan.
The Order addressed permit violations.
The Order addressed CSOs in violation of permit. This Order
eventually resulted in a judicial referral.
K-17
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Report to Congress on the Impacts and Control of CSOs and SSOs
K-18
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Appendix K
K.4 Federal SSO Administrative Orders
Region State Case Name/City Name Effective Date
1
MA
Town of Winchendon
10/16/00
Description
This Order required the permitee to implement a block testing
program to determine the frequency of Sanitary Sewer Overflow
(SSO) occurrence and report these results to EPA and
Massachusetts Department of Environmental Protection (MADEP).
The order also required that an update to the 1998 Preliminary
Design Report be submitted to include recommendations on
measures necessary to ensure compliance with the NPDES permit.
Puerto PRASA Bayamon WWTP 11/20/02
Rico
Puerto PRASA Bayamon WWTP 12/23/02
Rico
Puerto PRASA Puente Blanco 12/23/02
Rico Pump Station &
Collection System
Puerto PRASA Puente Blanco 01/16/01
Rico Pump Station &
Collection System
PA Prospect Borough 04/27/01
The order required that Puerto Rico Aqueduct and Sewer Authority
(PRASA) take immediate steps to unclog and clean all sewer
pipelines and manholes causing sewage bypasses.
The order required that PRASA take immediate steps to unclog and
clean all sewer pipelines and manholes causing sewage bypasses
A $104,000 penalty was assessed for failure to provide proper
operation and maintenance leading to the discharge of partially or
untreated pollutants to waters of the U.S.
The Order addressed NPDES permit violations.
This Order required them to install and operate the flow
equalization tank to eliminate overflows of their sewage. The Order
further required the City submit a detailed Compliance Plan,
conduct an SSES and establish actions to address deficiencies
detected in the SSES, and establish a comprehensive
management, operation and maintenance (CMOM) program.
KY City of LaGrange
05/09/01
KY City of Radcliff Sewerage 05/09/01
System
The Order required them to establish numerous programs and
evaluate and revise existing programs to achieve continuous
compliance with its Permit.
The Order required them to establish engineering, continuing sewer
assessment, infrastructure rehabilitation, system capacity
assurance, and pump station operation programs and to evaluate
and revise existing programs to remediate the causes of the
discharges of untreated pollutants to waters of the U.S.
K-19
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
4 MS City of Moss Point Sewer 09/28/01
System
4 MS City of Ocean Springs 06/05/01
4 MS City of Pascagoula Sewer 12/04/01
System
4 MS City of Pass Christian 09/09/02
Sewerage System
MS Gautier Utility District 03/26/01
Sewer System
SC City of Simpsonville 02/04/03
4 SC City of Travelers Rest 11/15/02
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
TN
Diamondhead Water & 10/18/02
Sewer District Sewer
System
Fountain Inn
06/27/02
Gantt 04/29/03
Georgetown 04/01/03
Greer 03/20/03
Laurens County Water 08/12/02
and Sewer Commission
Marietta Water, Fire,
Sanitation and Sewer
District
09/06/02
Piedmont 05/27/03
Taylors 03/04/03
Wade Hampton Fire and 12/16/02
Sewer District
Rockwood Water and 02/19/02
Gas
Description
The Order required them to establish numerous programs with
respect to collection system assessment, operations and
maintenance, and evaluate and revise existing programs to achieve
continuous compliance with the Permit.
The Order required them to establish numerous programs with
respect to collection system assessment, operations and
maintenance, and evaluate and revise existing programs to achieve
continuous compliance with the Permit.
The Order required them to establish numerous programs with
respect to collection system assessment, operations and
maintenance, and evaluate and revise existing programs to achieve
continuous compliance with the Permit.
The Order required them to establish numerous programs with
respect to collection system assessment, operations and
maintenance, and evaluate and revise existing programs to achieve
continuous compliance with the Permit.
The Order required them to establish numerous programs with
respect to collection system assessment, operations and
maintenance, and evaluate and revise existing programs to achieve
continuous compliance with the Permit.
The Order required them to establish numerous programs with
respect to collection system assessment, operations and
maintenance, and evaluate and revise existing programs to achieve
continuous compliance with the Permit.
The Order required them to establish numerous programs with
respect to collection system assessment, operations and
maintenance, and evaluate and revise existing programs to achieve
continuous compliance with the Permit.
The Order required them to establish numerous programs with
respect to collection system assessment, operations and
maintenance, and evaluate and revise existing programs to achieve
continuous compliance with the Permit.
The Order required the City to review, evaluate, and revise its
current Management Program. Additionally, a Training Program, a
Safety Program, and the Engineering Program were to be revised
and/or developed within 18 months.
No additional information provided.
No additional information provided.
No additional information provided.
The Order required them to establish numerous programs with
respect to collection system assessment, operations and
maintenance, and evaluate and revise existing programs to achieve
continuous compliance with the Permit.
The Order required the City to review, evaluate, and revise its
current Management Program. Additionally, a Training Program, a
Safety Program, and the Engineering Program were to be revised
and/or developed within 18 months.
No additional information provided.
No additional information provided.
The Order required them to develop a financing and cost analysis
program and a contingency plan for sewer.
The order required review, evaluate, revise and/or develop
collection system management programs, including Engineering
Programs.The City was required to maintain a Pump Station
Maintenance and Grease Control Program.
K-20
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Appendix K
Region State Case Name/City Name Effective Date
TN West Knox Utility District 10/29/01
IL City of Rock Island, Rock 02/13/98
Island
IN Fort Wayne 01/17/96
IN Fort Wayne 1995
IN Lawrence STP 09/30/02
IN Town of West College 03/22/02
Corner
Description
The order required the establishment of numerous collection
system management programs, including the Information
Management Systems/Programs and Engineering Programs, to be
implemented within 12 months.
The Order required that a plan of action for achieving compliance
must be submitted to EPA for approval within 11 months
The order required the City to prepare and submit an SSO
elimination plan to be implemented upon approval or within 45 days
of submittal, whichever came first.
No additional information provided.
The Order addressed permit violations.
The Order required that the City submit certain information to EPA
stating: the current status of compliance for each item on the IDEM
approved action plan and the costs associated with each activity,
and the needed plant improvements to come into consistent
compliance with the NPDES permit, including proposed time to
construct and the costs of construction.
IN Town of West College
Corner
OH City of Fostoria
OH City of Willoughby Hills 09/26/01
OH Lake County
OH Licking County Buckeye 02/05/97
Lake Sewer District No. 1
WWTP
OH Village of College Corner 03/22/02
Wl City of South Milwaukee 03/19/01
AK City of Hot Springs
12/08/97 The Order required that the Town will submit a Compliance Plan
(CP) to the Indiana Department of Environmental Management
(IDEM) for approval within 30 days.
09/27/01 The Order required the City to submit a detailed Plan of Action
containing a fixed date schedule describing actions taken, or, to be
taken, to eliminate Outfall 009E which are not in accordance with
the NPDES permit.
The order required the City to eliminate the discharge of raw or
partially treated sewage within 20 days. The City plans to install
sanitary sewers in the Oak Street area to alleviate the failing septic
system.
09/26/01 The Order required the County to eliminate the discharges of raw or
partially treated source within 20 days.
The order required the preparation of a detailed plan of action to
eliminate SSOs.
The Order required that the City submit certain information to EPA.
The Order required that by 11/30/01, the City will eliminate the
sanitary flow restrictive junction at 15th Avenue and Manitowac
Avenue, install manhole liners in 1,000 manholes and upgrade the
Lake Drive Lift Station.
06/02/00 Within one month of this Order, the City will submit a
comprehensive plan for the expeditious elimination and prevention
of unauthorized discharges and overflows of wastewater from its
collection system. The plan will provide specific actions to be taken
and include a schedule for achieving compliance.
K-21
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
6 LA City of Opelousas 06/06/02
LA City of Opelousas 04/30/99
6 LA City of Rayne
2002
LA City of Shreveport 07/29/97
LA City/Parish of East Baton 09/09/94
Rouge
LA City/Parish of East Baton 01/30/98
Rouge
NM City of Carlsbad
08/29/00
TX City of Austin
TX City of Austin
TX City of Austin
06/10/99
10/25/99
04/29/99
Description
The Order required that the City provide a comprehensive
construction progress summary to EPA for Phase I and Phase II
rehabilitation activities within one month
This Order required that all projects for the Phase I, Collection
System Rehabilitation will be complete by 08/31/99. The Order also
required that all projects for the Phase II, Collection System
Rehabilitation will be complete by 09/31/01 and that all projects for
the Phase III, Collection System Rehabilitation will be complete by
07/31/02.
The Order required that the City take whatever corrective action is
possible to eliminate and prevent recurrence of the violations within
one month. If one month is not possible, then the City will submit an
action plan detailing how the City intends to eliminate overflows in
the collection system in the shortest amount of time possible. This
plan will include a schedule for eliminating overflows in the
collection system.
The Order required that the City take whatever corrective action is
possible to eliminate and prevent recurrence of the violations within
one month. If one month is not possible, then the City will submit an
action plan detailing how the City intends to eliminate overflows in
the collection system in the shortest amount of time possible. This
plan will include a schedule for eliminating overflows in the
collection system.
This Order was issued requiring the City to report past SSOs from
its collection system and to continue reporting those SSOs in
tabular form along with its monthly Discharge Monitoring Report
(DMRs).
The Order required that the City take whatever corrective action is
possible to eliminate and prevent recurrence of the violations within
one month. If one month is not possible, then the City will submit an
action plan detailing how the City intends to eliminate overflows in
the collection system in the shortest amount of time possible. This
plan will include a schedule for eliminating overflows in the
collection system.
The Order required that the City take whatever corrective action is
possible to eliminate and prevent recurrence of the violations within
one month. If one month is not possible, then the City will submit an
action plan detailing how the City intends to eliminate overflows in
the collection system in the shortest amount of time possible. This
plan will include a schedule for eliminating overflows in the
collection system.
A penalty of $27,500 was assessed based on, among other things,
the number of violations the City committed.
The civil penalty of $21,000 listed in this Order settles all violations.
The Order required that the City perform numerous pump station
upgrades, carry out infiltration and inflow (I/I) and SSES studies,
and implement remedial actions. The Order required that
compliance be achieved by 12/31/07.
K-22
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Appendix K
Region State Case Name/City Name Effective Date
6
TX City of Austin
09/11/98
Description
The Order required that the City take whatever corrective action
was possible to eliminate and prevent recurrence of the SSOs
within one month. If one month was not possible, then the City was
to submit an action plan detailing how the City intended to eliminate
overflows in the collection system in the shortest amount of time
possible. This plan will include a schedule for eliminating overflows
in the collection system.
TX City of Dallas
10/25/00 Within one month of this Order, the City will take whatever
corrective action is possible to eliminate and prevent recurrence of
the violations. If one month is not possible, then the City will submit
an action plan detailing how the City intends to eliminate overflows
in the collection system in the shortest amount of time possible.
This plan will include a schedule for eliminating overflows in the
collection system. A $27,500 penalty was assessed.
6 TX City of Dallas
TX City of Denton
TX
TX
City of Denton
City of Denton
TX City of Denton
TX City of Galveston
TX City of Galveston
TX City of Galveston
08/08/00 This Order was issued requiring the City to take corrective action to
prevent a discharge to occur again and set up a meeting with EPA.
07/26/02 The City will complete construction of Pecan Creek WWTP
improvements by 01/04. The City will complete construction of
Cooper Creek Lift Station Improvements and the Pecan Creek
Interceptor Phase I by 06/04. The City will complete construction of
Pecan Creek Interceptor Phase II by 10/05.
09/19/02 A $137,500 penalty was assessed.
06/30/99 EPA provided the City with a list of scheduled activities. The City
will follow the schedule so that the violations due to
overflows/unauthorized discharges from the collection system of the
POTW will be corrected.
01/14/99 The Order required that the City take whatever corrective action is
possible to eliminate and prevent recurrence of the violations within
one month. If one month is not possible, then the City will submit an
action plan detailing how the City intends to eliminate overflows in
the collection system in the shortest amount of time possible. This
plan will include a schedule for eliminating overflows in the
collection system.
05/18/01 This Order modified the schedule for construction improvements.
Complete the Lift Station Improvements and the Trunk Sewer
Improvements (trunk sewers without adequate capacity) by
12/31/01. Complete the Trunk Sewer Improvements (to prevent
overflows under surcharge conditions) by 12/31/02. All overflows
and bypasses of the collection system will be eliminated by
01/31/03.
12/18/00 A$14,850 penalty was assessed.
07/26/99 The Order modified the schedule for construction improvements. It
required the completion of the Lift Station Number One Upgrade by
03/31/00. It required the completion of the Trunk Sewer
Improvements (trunk sewers without adequate capacity and Lift
Station Improvements) by 12/31/01. All overflows and bypasses of
the collection system must be eliminated by 01/01/02.
K-23
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
6 TX City of Galveston
12/09/96
TX City of Galveston
6 TX City of Humble
10/07/96
1998
TX City of Jacksonville 02/22/99
TX City of Jacksonville 10/22/97
6 TX City of Nederland 05/30/97
6 TX City of Nederland 09/16/96
6 TX City of Nederland 01/31/95
6 TX City of South Houston 09/17/98
TX City of South Houston 06/25/96
6 TX City of South Houston 01/23/96
TX San Antonio Water
System
07/11/96
Description
This Order required that the City complete the Port Industrial Main
improvements, the 10th Street Trunk replacement/Jones Drive
replacement, manhole rehabilitation and structural repairs, and
trunk sewer improvements. All improvements were to be complete
by 06/30/01.
This Order incorporated a compliance schedule, submitted by the
City, for the elimination of wet weather and dry weather overflows
throughout the collection system.
The Order required that the City take whatever corrective action is
possible to eliminate and prevent recurrence of the violations within
one month. If one month is not possible, then the City will submit an
action plan detailing how the City intends to eliminate overflows in
the collection system in the shortest amount of time possible. This
plan will include a schedule for eliminating overflows in the
collection system.
The Order required that the City complete the rehabilitation of the
western portion of the collection system by 06/01/99, complete the
Sewer System Improvements, Line B4 by 11/01/00, complete the
Sewer System Improvements, Line B2 by 04/01/02, and complete
more specified improvements on an annual basis.
The Order required that by 08/31/98, the City submit to EPA a
construction schedule for all improvements necessary to eliminate
overflows from their collection system.
The Order required that the City will complete a SSES and submit a
schedule for the rehabilitation of all system defects not completed
during the SSES by 07/98.
This Order was issued for overflows from the sewer system.
This Order was issued requiring, among other things, that the City
submit a plan and schedule for mitigating of the effects of the I/I on
the system and the immediate elimination of the bypass located on
Avenue C.
Within one month of this Order, the City will take whatever
corrective action is possible to eliminate and prevent recurrence of
the violations. If one month is not possible, then the City will submit
an action plan detailing how the City intends to eliminate overflows
in the collection system in the shortest amount of time possible.
This plan will include a schedule for eliminating overflows in the
collection system.
The Order required that the City take whatever corrective action is
possible to eliminate and prevent recurrence of the violations within
one month. If one month is not possible, then the City will submit an
action plan detailing how the City intends to eliminate overflows in
the collection system in the shortest amount of time possible. This
plan will include a schedule for eliminating overflows in the
collection system.
This Order was issued requiring compliance with a schedule for
Activity Numbers One thru Four in the Industrial User Survey
submittals.
The Order required that the System perform an I/I study of their
collection system to include flow monitoring. A submission of
schedules for rehabilitation was required when the studies were
complete.
K-24
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Appendix K
Region State Case Name/City Name Effective Date
6 TX San Antonio Water 04/14/94
System
7 MO City of Campbell 04/04/01
7 MO City of Platte City 05/22/02
7 MO City of Platte City 12/10/02
10 AK City and Borough of 09/11/00
Juneau, Alaska,
Mendenhall Wastewater
Treatment Facility
Description
The Order contained a schedule for the installation of permanent
flow meters and a study of the collection system. The schedule was
modified 04/11/96.
Action taken to eliminate SSOs.
A $60,000 penalty was assessed.
The City will immediately pay a $15,000 penalty. Upon satisfactory
completion of multiple SEPs projects, the remaining $45,000 of the
total ($60,000) will be suspended. The SEPs were intended to
serve as significant environmental or public health protection and
improvement.
The Order required that a written plan for the elimination of
unauthorized discharges be submitted to EPA within one month.
The plan must include provisions for a thorough study of the
collection system, a plan for addressing the problems identified and
a schedule of completion for activities
10 WA Lummi Indian Business
Council of the Lummi
Nation, WA
07/29/02 The Order required that the Council perform various wastewater
treatment plant upgrades and to investigate and seek available
funding mechanisms for the Lummi Shore collection system
upgrade by 12/31/02.
K-25
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Report to Congress on the Impacts and Control of CSOs and SSOs
K-26
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Appendix K
K.5 Federal CSO Administrative Penalty Orders
Region State Case Name/City Name
1 MA City of Fitchburg
MA Town of Palmer
Effective Date Penalty Amount
02/02/96;
Amended
07/02/96
01/06/97
$208,800
$5,000
K-27
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Report to Congress on the Impacts and Control of CSOs and SSOs
K-28
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Appendix K
K.6 Federal SSO Administrative Penalty Orders
Region
2
3
5
6
6
6
6
6
7
7
10
State
Puerto
Rico
PA
IN
TX
TX
TX
TX
TX
MO
MO
AK
Case Name/City Name
PRASA Puente Blanco Pump Station &
Collection System
Monaca Borough
Town of West College Corner
City of Austin
City of Austin
City of Dallas
City of Denton
City of Galveston
City of Campbell
City of Platte City
City and Borough of Juneau, Mendenhall
Wastewater Treatment Facility
Effective Date
12/23/02
05/20/99
12/08/97
10/25/99
06/1 0/99
10/25/00
09/19/02
12/18/00
04/04/01
05/22/02
09/11/00
Penalty Amount
$27,500
$18,000
$24,062
$21,000
$27,500
$27,500
$137,500
$14,850
$87,500
$60,000
$60,000
10 AK City and Borough of Juneau, Mendenhall
Wastewater Treatment Facility
08/15/01
$30,000
K-29
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Report to Congress on the Impacts and Control of CSOs and SSOs
K-30
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Appendix K
K.7 State CSO Judicial Orders
Region State Case Name/City Name Effective Date
1 ME City of Bangor and State Entered
of Maine 06/30/87;
Amended
12/01/87
1 ME City of Bangor and State 04/09/91
of Maine
NJ Borough of East Newark 02/11/99
NJ Borough of Fort Lee 08/16/95
NJ City of Bayonne
NJ City of Bayonne
08/24/00
08/01/00
NJ City of Kearny
02/11/99
NJ City of Paterson
05/22/02
NJ Village of Ridgefield Park 08/20/99
Description
NJ Village of Ridgefield Park 07/22/98
This Order addressed NPDES permit violations. The City was
required to pay a $40,000 civil penalty which provide other relief for
certain violations of the NPDES permit requirements.
The City completed a short-term sewer rehabilitation project for a
previous State Consent Order and has begun long-term sewer
rehabilitation and Combined Sewer Overflow (CSO) abatement
projects.
The Order required that within 12 months of East Newark's receipt
of the Department's Stage ll/lll TWA, the Borough will complete the
required construction and commence operation of the approved
treatment works.
The Order addressed failure to meet the discharge of
solids/floatable requirements established in the 1995 Administrative
Consent Order.
This was a settlement between both parties stating that both parties
had voluntarily agreed to a settlement and that the agreement fully
disposed of all issues in controversy and was consistent with the
law.
The Order required that construction of the Group One CSO Points
006 and 015 will be complete by 07/22/99. Within 15 months from
the Department's issuance of the Stage ll/lll Treatment of Works
Approval (TWA) for the Group I CSO points, construction will be
complete and the Solids/Floatables control measures will be
implemented. Within 15 months of Bayonne's receipt of the
Department's Stage ll/lll TWA, the Group Two CSO Points required
construction will be complete.
The Order required that within 12 months of the City's receipt of the
Department's Stage ll/lll TWA, the City will complete the required
construction and commence operation of the approved treatment
works. By 01/31/00, the City will complete construction for the
Storm Sewer System 1A (Sewer Separation Project).
The Order required the City to complete construction of Romag
CSO Points 30 and 31 by 06/01/05. The City will complete
construction of Romag CSO Point 16 by 06/01/04. The City will
complete construction of Romag CSO Points 25, 27, and 29 by
12/01/07. The City will complete construction of the sewer
separation by 12/31/04.
The Order required, among other things, construction of the
approved Long-term Solids/ Floatables Control Measures will be
complete within nine months of receipt of Department's Stage ll/lll
approval. Construction will be complete for the Solids/Floatables
Control Facilities at outfall 001 and outfall 002 by 01/17/00, at
outfall 003 by 11/30/99, at outfall 005 by 12/01/99, and at outfall
006 by 11/09/99.
The Order addressed permit violations.
K-31
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
Description
NY Onondaga County
Department of Drainage
and Sanitation and,
Onondaga County
01/20/98 The County was required to design, test, and construct
modifications and additions to the Metro facility, including diversion
of the Metro's effluent to the Seneca River. By 11/01/03, the County
will complete construction of the Full Scale Ammonia Removal
Project. By 04/01/05, the County will complete construction of the
Phosphorus Removal/ Effluent Filtration Project. By 06/01/02, the
County will complete construction and commence full operations of
all projects to achieve Stage III effluent limits, or achieve revised
effluent limits.
NY Onondaga County 02/01/89
Department of Drainage
and Sanitation and,
Onondaga County
MD Frostburg (The Mayor 12/14/01
and Town Council of)
MD The City of Cambridge 02/05/99
(The Mayor and
Commissioners of)
The County was obligated to develop a Municipal Compliance Plan
that would bring the County's effluent discharges from the Metro
facility and the CSOs into compliance with the State's effluent
limitations and water quality standards, and then implement such a
plan.
Immediately following the Department's approval of its LTCP,
Frostburg will begin implementation of the LTCP and then complete
implementation of the LTCP in accordance with the approved
schedule.
This Order stated that within 11 months of the notice to proceed
construction, the City will complete construction of the interceptor
work along Water Street and complete separation of the combined
sewer and storm water lines along Mill Street and Vue de L'eau
Street. Within seven months of the respective notice to proceed
with construction of the Phases II, III, IV, V, and VI improvements,
complete construction of Phases II, III, IV, V, and VI improvements.
MD The City of Cambridge
(The Mayor and
Commissioners of)
11/23/93 The Order required the City to improve the Cambridge Wastewater
Treatment Plant and the sewer system. The City will also submit a
study, plan and schedule for improvements to the sewer system
design to alleviate wastewater discharges into any and all streets.
MD Westernport (The Mayor 08/23/02
and Town Council of)
Within one month after this Consent Decree, Westernport will
implement all elements of the Nine Minimum Controls (NMCs).
Within one month following the Department's approval of its Long-
Term Control Plan (LTCP) and schedule, Westernport will
implement its LTCP.
K-32
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Appendix K
K.8 State SSO Judicial Orders
Region State Case Name/City Name Effective Date
NJ Rahway Valley Sewerage 07/09/01
Authority (RVSA)
Description
Within 31 months of this Order, RVSA will complete construction of the
Final Effluent Polishing Facilities, Disinfection Facilities, Pumping
Facilities, Sampling Chambers, and Auxiliary Power. Within 31 months
of completion of Phase I, Phase II construction will be complete.
VA District of Columbia, 01/25/02
Fairfax
WV Crab Orchard/ MacArthur 02/04/00
Public Service District
In this Order, the District agreed to pay the Commonwealth $325,000
in settlement of violations and close the Lorton facility.
This Consent Decree was issued for failure to comply with State water
quality standards and effluent limitations for discharging pollutants into
the Piney Creek and other waters of the State, for violating their
NPDES Permit, and for failure to comply with several orders.
WV St. Albans Municipal Utility 10/13/98
Commission, City of St.
Albans
This Consent Decree was issued for failure to comply with state water
quality standards and effluent limitations for discharging pollutants into
the Kanawha River and other waters of the State, for violating their
NPDES Permit, and for failure to comply with several orders.
AL The City of Brent, Brent 01/30/02
Water and Sewer Board,
City of Centreville, and the
Centreville Waterworks
and Sewer Board
Within 12 months of this Order, they will repair Pump Stations
Numbers One, Two, Three, Four, and Five in the Centreville and Brent
collection system.
AL The Water Works and 01/30/97
Sewer Board of the City of
Prichard
Within 420 days of this Order, the construction of the Gumtree Branch
replacement sewer line or any other cost-effective remedy approved
by Alabama Department of Environmental Management will be
complete. Within 1,230 days of this Order, the construction of the new
side stream storage facility will be complete.
K-33
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Report to Congress on the Impacts and Control of CSOs and SSOs
K-34
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Appendix K
K.9 State CSO Administrative Orders
Region State Case Name/City Name Effective Date
Description
1
ME City of Bath
01/09/92 Before 06/01/93, the City will submit to the Department for review
and approval a master plan for abatement of Combined Sewer
Overflows (CSOs) from its sewerage system, including a schedule.
The City will also develop a long-term Pump Stations Facility Plan,
including a schedule. By 07/01/92, develop a Comprehensive
Treatment Plant Facilities Plan to address the current and future
needs of the City to achieve state of the art wastewater treatment
consistent with its discharge license limitations.
ME City of Biddeford
ME City of Brewer and
Eastern Fine Paper
Company
07/22/91 The Order required, among other things, that by 01/01/93, they will
complete sewer system improvement projects in order to eliminate
or abate CSO discharges. Beginning in 01/92, the City will complete
all other CSO abatement projects described in the approved interim
and final Sewer System Master Plan.
02/27/92 The Order required a CSO Master Plan will be submitted to the
Department before 06/01/93. This master plan will include a
schedule for implementation and construction of all projects.
ME City of Westbrook, 10/21 /91
Portland Water District,
Westbrook
ME The City of Portland and 02/13/91
Portland Water District
ME Town of Bucksport
03/01/90
ME Town of Lisbon
05/24/90
The Order required that by 12/91, Westbrook and Portland Water
District will complete all projects listed and described in the Final
Sewer System Master Plan.
The Order required that by 12/93, Portland and Portland Water
District will complete sewer system improvement projects in order to
eliminate or abate CSO discharges.
The Order required that by 02/01/90, the Town will submit to the
Department for review and approval, plans and a schedule for the
installation of chlorination/dechlorination facilities. By 02/15/90, the
Town will submit to the Department for review and approval a plan
monitoring CSOs from its sewage system.
The Order required that by 05/01/90, the Town will submit to the
Department for review and approval, a process control plan to
specifically deal with filamentous bulking. The Town will also submit
to the Department for review and approval, a pump station and
sewer maintenance program, including a time schedule for
implementation of this pump station and sewer maintenance plan.
ME Town of Lisbon
04/13/88 The Order addressed upgrading the Town's secondary wastewater
treatment facilities.
K-35
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
NJ Borough of Fort Lee 06/01/95
NJ Camden County 02/27/98
Municipal Utilities
Authority
NJ Camden County 03/31/97
Municipal Utilities
Authority
NJ City of Camden 08/23/99
NJ City of Camden 03/31/97
NJ City of Gloucester 07/22/99
NJ City of Gloucester
NJ
03/31/97;
Amended
^^^^^^^^^^ 06/30/98
City of New Brunswick 04/25/94
NJ City of Newark 05/21/01
NJ City of Newark 12/07/98
NJ City of Paterson 02/01/99
NJ City of Perth Amboy 07/26/95
Description
The Order required that within 15 months of the Borough's receipt
of the New Jersey Department of Environmental Protection's
(NJDEP's) Stage ll/lll approval, the Borough will complete
construction and commence operation of the approved Long-term
Solids/Floatables Control Measures.
The Order addressed, among other things, permit violations.
The Order addressed, among other things, permit violations.
The City was required to fully implement the O&M Program and
develop and implement the CSO Pollution Prevention Plan by
09/30/99.
The Order addressed, among other things, permit violations.
The Order addressed, among other things, permit violations. The
City was supposed to plan, design, improve, operate and maintain
its combined sewer system (CSS) as required and set forth by its
permit.
The Order addressed, among other things, permit violations.
The Order required that within six months from the start of
construction for the backflow prevention device, the construction
will be complete. Additionally, the City was required to submit a time
table for attaining the completion of the sewer separation project by
12/01/94.
Under this Order, the City was required to complete construction
and commence operation of the Long-Term Solids/ Floatable
Control Plan for all its CSO points within 15 months of the City's
receipt of the Department's Treatment of Works Approval (TWA).
The Order addressed the City's noncompliance with its permit.
The Order addressed permit violations.
The City was required to complete construction and eliminate the
illegal discharges from the homes located on High and Hartford
Streets at the corner of Buckingham Avenue, complete construction
for the Budapest sewer separation project, eliminate the raw
sanitary waste water discharge from DSN 001, and permanently
close the seal at DSN 001. The City was also required to complete
the upgrades/ repairs to the State Street, Front Street, and Amboy
Avenue pump stations within 12 months of beginning construction
and complete the repair of the CSO pipes at DSN 002 and DSN
017 within six months.
K-36
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Appendix K
Region State Case Name/City Name Effective Date
NJ City of Perth Amboy
NJ City of Rahway
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
09/30/93
05/08/00
Edgewater Municipal
Utilities Authority
09/30/93
09/30/93
Hoboken/Union
City/Weehawken
Sewarage Authority
(HUCWSA)
Middlesex County Utilities 04/13/95
Authority
Middlesex County Utilities 06/05/96
Authority (MCUA)
Rahway Valley Sewerage 09/30/93
Authority (RVSA)
Town of Guttenberg 09/30/93
Town of North Bergen 12/13/95
Municipal Utilities
Authority (NBMUA),
Town of Guttenberg/
Woodcliff Sewage
Treatment Plant
Town of North Bergen 09/30/93
Municipal Utilities
Authority (NBMUA),
Town of Guttenberg/
Woodcliff Sewage
Treatment Plant
Description
The City was required to complete construction and implementation
of a project that is used to control the discharge of solids/ floatables
and properly dispose of solids/ floatables by 03/01/97.
This Order required the City to complete construction necessary to
remove the identified sources of inflow contributing to outfalls 001,
004 and 005 by 11/01/03. Additionally, the City was required to
complete construction necessary for the separation of the combined
sewer tributary to outfalls 003 and 004 by 03/01/03. The City was
required to complete construction necessary to remove the
identified sources of inflow contributing to outfalls 002 and 003 by
05/01/04. The City was also required to complete construction
necessary for the separation of the combined sewer tributary to
outfall 002 by 03/01/04.
The Order required the City to complete construction and
implement measures to control the discharge of solids/ floatables
and properly dispose of these solids/floatables by 03/01/97.
Under this Order, HUCWSA will complete construction and
implementation of a project that is used to control the discharge of
solids/ floatables and properly dispose of solids/ floatables by
07/01/97.
This Order addressed violations of the Water Pollution Control Act
(WPCA), implementing regulations, and its permit.
The Order required MCUA to complete the upgrade of the worse 20
metering chambers to accurately measure all flows, including peak
flows during storm events by 10/01/97. MCUA was also required to
complete the upgrade of all of the remaining metering chambers to
accurately measure all flows, including peak flows during storm
events by 04/01/98, .
RVSA was required to complete construction and implementation of
a project that is used to control the discharge of solids/ floatables
and properly dispose of solids/ floatables by 03/01/97.
This Order addressed the failure to comply with its permit, the
WPCA, and the SNA.
This Order required NBMUA to complete construction and
commence operation of the control measures in the Interim Solids/
Floatables Control plan within 12 months of the NBMUA's receipt of
NJDEP's Stage ll/lll approval. Also, NBMUA will complete
construction and commence operation of the Long-Term Solids/
Floatables Control measures within 15 months of receipt of
NJDEP's Stage ll/lll approval.
This Order addressed the failure to comply with its permit, the
WPCA, and the Sewage Infrastructure Improvement Act (SNA).
K-37
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
NJ West New York Municipal 09/30/93
Utilities Authority
(WNYMUA)
NY New York City, 06/26/92
Department of
Environmental Protection
(NYDEP)
NY New York City, Modification
Department of 03/96
Environmental Protection
(NYDEP)
Description
Under this Order, WNYMUA will develop and implement technology-
based control measures to address the minimum technology-based
limitations by 10/01/95. Additionally, WNYMUA will complete
construction/ implementation of the Long-Term Solids/ Floatables
Control Measure Strategy by 03/01/97.
The Order required the NYDEP to establish an environmental
benefit program, costing $250,000; continue its CSO abatement
program, including the Track One CSO Abatement (DO and
Coliform) and the Track Two CSO Abatement (Floatables); and
supplement the data collection gathered as part of the NY/NJ
Harbor Estuary Program and gather additional information
concerning the contribution of heavy metals to the Harbor from
CSOs.
In addition to the CSO Abatement Program required by the 1992
Order, this modification required the NYDEP to add another
program which consisted of the inspection, inventory, mapping,
replacement of missing hoods, and cleaning to facilitate inspection
and hood replacement of those catch basins located in Phases I &
II areas identified in this Order. They were required to retain a
consulting firm to perform the inspections of each of the catch
basins identified. Additionally, they were required to submit a scope
of work to determine an appropriate and cost-effective catch basin
cleaning program for floatables capture and flood control in specific
locations throughout the City.
DE City of Wilmington
MD Mayor and City Council 12/30/96
of Frostburg
TN Metropolitan Government 09/17/99
of Nashville and
Davidson County
5 IN City of Bluffton
5 IN City of Boonville
5 IN City of New Castle
5 IN City of Sullivan
02/06/03 The Order required the City to modify the significant industrial users
(SlUs) permits, determine whether any dry weather flow from a
CSO is an overflow or infiltration, and notify the citizens of when
and where CSOs occur.
This Order was issued requiring them to implement a CSO Control
Program or a plan to enable it to comply with the EPA CSO Control
Policy, including NMCs by 07/01/97.
The City and County was required to have all CSO controls,
including but not limited to, floatable material and debris removal,
combined sewage storage and/or detention and CSO elimination, in
place by 07/01/01. The City and County will eliminate all overflows
or bypassing from its sanitary sewers to all waters of the state by
07/01/01. Of the total $600,000 penalty, $100,000 will be due within
one month of this Order. However, in lieu of the $100,000, a SEP
may be performed by the City and the County.
06/24/03 This Order required the City to immediately implement the approved
LTCP and adhere to the milestone dates.
11/25/02 This Order required the City to immediately implement the approved
LTCP and adhere to the milestone dates.
01/27/03 This Order required the City to immediately implement the approved
LTCP and adhere to the milestone dates.
01/22/03 This Order required the City to immediately implement the approved
LTCP and adhere to the milestone dates. Also, the City was
required to submit to IDEM a Compliance Plan, including a
construction schedule by 03/01/03.
K-38
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Appendix K
Region State Case Name/City Name Effective Date
IN Town of Centerville 11/25/02
IN Town of Remington 06/06/03
IN Town of Ridgeville 09/11/02
IN Town of Ridgeville 10/15/01
IN Town of Summitville 01/29/03
MO City of Macon, MO 05/29/01
MO City of Sedalia, MO
10
OR City of Astoria
10 OR City of Astoria
10 OR City of Corvallis
10 OR City of Portland
06/15/92;
Amended
02/10/03
01/07/93
08/05/02
11/09/92
08/11/94
10 OR City of Portland
10 WA City Of Spokane
Description
This Order required the Town to submit to Indiana Department of
Environmental Management (IDEM) the CSO Operational Plan and
the Stream Reach Characterization Evaluation Report as soon as
possible but no later than 06/01/03, and complete the LTCP.
The Order required the Town to complete construction, cease
overflows from Outfall 004, and provide IDEM a certification
statement of completion of construction within nine months of this
Order.
This Order required the City to immediately implement the approved
LTCP and adhere to the milestone dates.
This Order required the Town to submit to the IDEM its complete
Stream Reach Characterization and Evaluation Report by 09/30/01
and submit its LTCP for approval by 03/15/02.
This Order required the City to immediately implement the approved
LTCP and adhere to the milestone dates.
This Order required that a schedule for the Nine Minimum Controls
(NMCs) be submitted by 06/01/01. Upon review and approval of the
LTCP and the schedule for implementation of the LTCP, the City
will complete each phase of the LTCP in accordance with the
approved schedule.
This Order required the City to complete construction of Phase I by
12/01/04, complete construction of Phase II by 12/01/05, and
complete construction of Phase III by 09/15/07.
The City has completed the studies and planning activities required
by the Order, and on 09/30/98, submitted a CSO Facilities Plan to
the Department.
This Order required the City to eliminate all untreated CSO
discharges within 15 months of Department approval of the Plans
and Specifications.
Under this Order the City was required to eliminate discharges that
violate applicable water quality standards, subject to storm return
frequencies at five CSO discharge points by 12/31/01.
Under this Order, the City was required to eliminate untreated CSO
discharges at 20 of the CSO discharge points, including discharges
to Columbia Slough by 12/01/01, eliminate untreated CSO
discharges at 16 of the remaining discharge points by 12/01/06,
and eliminate untreated CSO discharges at all remaining CSO
discharge points by 12/01/11.
08/05/91 Under this Order, they were required to carry out necessary studies
and corrective actions to eliminate the discharge of untreated
overflows from the combined sewer system, up to one in ten year
summer storm event and up to a one in five year winter storm
event. The City was required to submit scope of study for the
facilities plan and for an interim control measures study.
12/13/99 This Order addressed untreated sewage discharging from the City's
CSO outlet #15. A penalty of $15,000 was eventually assessed for
the violation.
K-39
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Report to Congress on the Impacts and Control of CSOs and SSOs
K-40
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Appendix K
K.10 State SSO Administrative Orders
Region State Case Name/City Name Effective Date
1
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NY
Bergen County Utilities
Authority Sewage
Treatment, Bergen
County
Cliffside Park Borough,
Bergen County
12/17/91;
Amended
05/20/97;
Amended
02/01/99
06/22/01
Borough of Flemington 10/20/99
Borough of Flemington 04/08/03
City of Summit 05/28/99
City of Summit
07/23/02
Englewood Cliffs Borough 05/15/97
Ewing-Lawrence 09/14/00
Sewerage Authority,
Trenton
West Milford Township 03/28/00
Municipal Utilities
Authority
CityofOneida 01/04/01
NY City of Sherrill
04/09/90
NY County of Westchester 08/17/98
Description
This Order required Bergen County Utilities Authority to complete
the Municipal Sewer Operations and Maintenance Program and
submit a final report to the Department by 10/01/05.
This Order required the Borough to plan, design, construct,
operate, and/or implement modifications to the collection and
conveyance facilities that will result in the elimination of major storm
water contributions to the CSOs from Sanitary Sewer Outlet Plan,
Regulator Ten. Construction was required to be completed by
06/01/02.
The Borough was required to immediately cease all unpermitted
discharges of pollutants emanating from its wastewater collection
system.
This Order addressed permit violations.
The City was required to immediately cease all unpermitted
discharges from the System and seal the overflow point from the
Chatham Road Pump Station holding tank.
This Order required the city to submit a comprehensive upgrade
plan with a time schedule by 08/01/02; within 12 months of
issuance of the Treatment Of Works Approval (TWA), the City was
to complete construction and installation and commence operation
of the additional pump(s).
This Order required the Borough to complete construction of
Category 1A by 04/01/02, and complete construction of Category
1B by 04/01/09.
Under this Order, Ewing-Lawrence Sewerage Authority was
required to complete private property I/I corrective action for all
properties which discharge into the sewage collection system
upstream of Jacobs Creek Diversion Chamber by 07/01/02.
This Order required the Authority to complete construction of the
recommendations of the Phase I Report by 10/16/02.
This Order required the City to submit for review an approvable
composite correction program with a proposed schedule of work
within two months of this Order, after Department approval of the
comprehensive performance evaluation final report.
This Order required the City to submit to the Department for
approval a plan and implementation schedule for bringing the City
into compliance with its flow limits of its State Pollutant Discharge
Elimination System (SPDES) permit within nine months of this
Order.
The County was required to complete all repairs to the Public I/I by
12/31/02, and complete construction of the SSO Treatment
Facilities for New Rochell S.D. Outfalls 003 and 005 by 04/01/04.
K-41
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
NY Mount Vernon Sewer 10/22/01
District, Hamburg
NY Town of Coeymans 05/04/01
NY
NY
NY
NY
NY
NY
NY
NY
Town of East Greenbush 11 /08/00
Town of Greenport 06/06/01
Town of North Greenbush 11/27/00
Town of North Greenbush Modified 10/2/01
Town of Owasco
06/11/01
Town of Sand Lake 07/21/00
Town of Tonawanda
Town of Tonawanda
01/02/87;
Revised
03/22/95
07/05/95
NY
Town of Tonawanda 02/87
NY Village of Attica
09/18/97
Description
This Order required the District to submit an engineering report for
abatement of all SSOs, including an approvable schedule, within six
months of this Order.
The Order required the Town to submit to the Department for
approval an I/I reduction plan to address excessive I/I within the
Town. They were also required to submit to the Department for
approval a detailed Wet Weather Operations Plan to minimize the
discharge of pollutants during wet weather and to prevent/minimize
upset conditions.
This Order required the Town to submit to the Department for
approval an I/I investigation plan by 01/15/01.
This Order required the Town to submit to the Department for
approval an I/I remedial plan and expeditious schedule by 08/01/02.
This Order required that by 10/15/00, the Town would submit to the
Department for approval an I/I removal plan that will result in the
elimination of excessive I/I within the sewer system.
The Order required the Town to submit to the Department for
approval an I/I remedial plan which was to include the results of the
I/I investigation by 01/01/02.
This Order required the Town to complete construction of Contract
Number One by 10/26/01, as well as complete construction of
Contract Number Two and eliminate existing sewer overflows by
02/28/02.
This Order required the Town to submit to the Department for
approval an I/I investigation plan which will include a schedule for
implementation by 08/15/00.
The Town was required to install 4,400 new sump pumps and
correct 1,650 existing sump pumps and 6,600 downspouts by
12/31/05.
The Town was required to submit to the Department for approval a
City Sanitary and Storm Sewer Management Plan by 09/01/95, and
eliminate 322 of the 446 cost effective private sources of inflow
identified in the City by 06/30/95.
This Order required the Town to submit a report detailing cost-
effective work which would minimize raw sewage overflows to
surface waters and the complete the required work established in
the schedule of this Order.
This Order required the Village to submit certification from a
professional engineer that the inflow removal Compliance Actions
would be completed according to the Schedule of Compliance
outlined in the permit by 11/01/97. The Order also required them to
submit a Plan of Study prepared by a professional engineer to
identify and remove all sources of excessive infiltration in the
Village's sanitary sewer collection system by 12/01/97.
K-42
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Appendix K
Region State Case Name/City Name Effective Date
NY Village of Cobleskill 07/22/98
2 NY Village of Cobleskill Modified
05/31/01
NY Village of Endicott 02/01/90
NY Village of Fort Ann 08/07/01
NY Village of Hancock
NY Village of Kenmore
01/31/02
NY
01/28/87;
Modified
06/09/95
Village of Saranac Lake 10/03/00
NY Village of Schuylerville 04/04/01
NY Village of Stamford
NY Village of Stamford
01/24/00
Modified
06/05/00
Description
This Order required that within 12 months of this Order,
construction of Phase I would be complete, within 24 months of this
Order, construction of Phase II would be complete, within 36
months of this Order, construction of Phase III would be complete,
and Phase IV would be complete within 48 months of this Order if
Phases l-lll do not adequately address I/I.
This Order required that by 12/31/01, the design and construction
of walls and additional piping in the aeration tanks would be
complete and by 06/15/01, bypasses to the wastewater treatment
facility would be eliminated. Additionally, construction of Phase I
was required to be complete within six months of this Order and
construction of Phase II would be complete within 24 months of this
Order.
This Order required the Village to submit to the Department a plan
to locate, install, and monitor newly installed wells by 03/15/90. The
Village was also required to submit to the Department for approval,
a Scope of Services report by 02/15/90 and within the appropriate
time frame, complete the Phase I and Phase II of the I/I
investigation.
This Order addressed permit violations and assessed a $17,000
penalty. Within 12 months of construction start, all corrective
measures were supposed to be complete.
This Order required the Village to have the valves located upstream
of the Brooklyn and Pennsylvania Avenue pump stations be
permanently closed by 06/01/02.
This Order required the Village to install sump pumps, if necessary,
by 05/01/89.
The City was required to implement all improvements to manhole
number ten by 11/30/00. The City will submit an approvable plan for
continuous ongoing sewer system assessment, flow monitoring,
correction and maintenance, including a schedule for each, by
02/28/01.
The Village was required to submit to the Department, within 14
months after completion of "the project," an engineering report that
evaluates the effectiveness of sump pump removal and
replacement of sanitary sewers and manholes at reducing I/I.
The Order required the Village to begin the I/I remedial work and
complete all work by 06/30/02.
This Order required that by 06/30/00, the Village would submit to
the Department for approval an I/I investigation plan.
K-43
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Report to Congress on Impacts and Control ofCSOs and SSOs
hJJJ!m4MM*U^JJM..IJi*PiJM..MJJJJJlUJ
2 NY Village of Williamsville 04/13/98
3 VA Caroline County Regional 04/01/02
WWTP, Caroline County
Description
This Order required the Village to submit to the Department for
approval a plan for continuous ongoing sewer system assessment,
flow monitoring, correction and maintenance, including a
compliance schedule by 09/01/97, as well as an engineering report
for abatement of discharges from sanitary sewer outfalls 001 thru
008 by 09/01/98.
This Order addressed violations of its permit for an unpermitted
discharge, failure to take reasonable steps to minimize or prevent
any discharge which has a likelihood of adversely affecting human
health or the environment, and failure to properly operate and
maintain systems. The County was required to develop and
implement written procedures for identification of potential collection
system problems; review and evaluate operation and maintenance
staffing; update all O&M manuals for the pumping stations and the
WWTP; and develop and implement an inspection program.
VA Commander, Navy
Region, Mid-Atlantic
(Regional Engineer)
This Order resolved certain violations of the State Water Control
Law and Regulations of the State Water Control Board. To correct
these violations, the Navy was supposed to install a cured-in-place
lining in the sewer line adjacent to pump station 1958; submit a
maintenance plan for grease traps for approval; submit a line-
cleaning plan for specific lines for approval; and submit a map and
list of all gravity sewer lines that have experienced overflow
problems all by 03/01/03.
VA Henrico County Water
Reclamation Facility,
Henrico County
VA Henrico County Water
Reclamation Facility,
Henrico County
VA Lorton Correctional
Complex STP, District of
Columbia Department of
Corrections, Fairfax
County
This Order addressed violations of environmental laws and
regulations, which required the County to begin implementation of
the Operation and Maintenance (O&M) manual and maintenance
schedule within three months of Department approval of the
manual. A schedule for completion of specific I/I projects was
supposed to be submitted for approval within two months of this
Order.
02/19/98 A Consent Order was issued to Henrico County due to SSOs of
sewage from its collection system. In a letter dated 01/08/02, the
County reported that all projects outlined in the Consent Order had
been completed except for one, which the Order required this
project to be completed by 01/01/03.
08/24/89; The 1989 Order required the District to upgrade the STP in phases
Amended to achieve compliance with more stringent permit effluent limits. In
08/20/92 and 1992, the construction schedule was amended at the District's
08/25/95 and request and the 1995 Amendment was in response to the District's
Canceled decision to construct the pumpover system and bring the STP off-
04/28/00 line.
K-44
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Region State Case Name/City Name Effective Date
VA Lorton Correctional 05/09/97;
Complex STP, District of Amended
Columbia Department of 8/15/00
Corrections, Fairfax
County
Appendix K
Description
The 1997 order required the District to, among other things,
eliminate overflows from the STP and collection system. The
District also had to comply with the permit and interim effluent limits
and eliminate the STP's discharge or, at a minimum, 0.5 MOD of
the discharge, by 08/01/99. A penalty of $25,000 was assessed.
The amended order required the District to maintain an adequate
staff of operators at the STP, secure the services of a consultant
engineering firm, and install a high-level alarm at the manhole that
overflowed at the corrections facility.
VA
VA
VA
Massaponax WWTP, 02/19/98
County of Spotsylvania
Massaponax WWTP, Amendment
County of Spotsylvania 11/25/98
Town of Vinton
The Order required the County to pay a civil penalty of $53,200 for
permit violations. The Order also required, among other things, that
the County operate the WWTP in a workman-like manner, in
compliance with the WWTP's Permit and O&M manual, in order to
ensure that overflows of raw or partially treated sewage are
eliminated.
This amendment required the County to submit revised plans,
specifications, and a schedule for review and approval for
upgrading and expanding the WWTP to meet specific permit limits;
operate the WWTP in a workman-like manner, and complete
construction of the upgrade and expansion by 01/15/03.
This Order addressed I/I issues that occurred in the collection
system. Three projects were initiated as a result of this order. The
first project was the Wolf Creek Sanitary Sewer Improvements
which called for the pump station and part of a gravity sewer pipe to
be replaced by 04/01/04. The second project was the Chestnut
Mountain Subdivision Sewer System Evaluation and Repairs which
called for the Town to complete repairs of the sewer line and
associated manholes serving that area by 02/15/05. The third
project is the Lindenwood Subdivision Sewer System Evaluation
and Repairs which required the Town to complete repairs of the
sewer line and the associated manholes in that area by 02/15/08.
VA U.S. Marine Corps,
Marine Corps Base
Quantico, Quantico
Mainside WWTP
This Order resolved certain violations of the State Water Control
Law and Regulations, particularly violations of exceeding effluent
limitations. By 08/30/02, the Department of Environmental Quality
(DEQ) was notified by Quantico that the WWTP's upgrade was
completed in accordance to approved plans.
WV City of Parkersburg Utility 08/26/02
Board, Parkersburg
In this Order, the City and Parkersburg Utility Board will maximize
flows to the treatment plant during both dry and wet weather
conditions in order to reduce the number, volume, and duration of
discharges from the City's SSOs. The City plans on completing
construction of the Long-term SSO Abatement Improvements by
10/31/09. A penalty of $12,500 was assessed.
K-45
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
WV City of South Charleston 12/18/98
Sanitary Board and South
Charleston Sewage
Treatment Company,
South Charleston
Description
The City was required to submit a CSO plan, complete and
implement the technology based controls established in the Order,
and complete an evaluation of water quality impacts. By 06/01/99,
they will submit a revised corrective action plan and compliance
schedule for the elimination of the 26 SSOs.
WV North Putnam Public
Service District, Scott
Depot
11/01/00 This Order required the District to proceed with the continued
implementation of the I/I identification and elimination measures
needed to eliminate extraneous flows, and, in the interim, utilize the
temporary sanitary sewer system overflow to alleviate potential
adverse conditions.
WV North Putnam Public Amended
Service District, Scott 04/13/01
Depot
WV Town of Athens 06/23/99
This amendment requested an extension to the compliance
schedule outlined in the 2000 Order.
This Order required the Town to immediately comply with the
interim limitations established in the Order. By 06/30/01, the Town
will either cease operation of their existing WWTP or have it
upgraded to meet the Permit requirements. Construction of the
treatment plant upgrade will be complete by 06/30/01.
WV Town of Winfield 04/16/02 The Town was required to immediately proceed with the continued
implementation of the I/I identification and elimination measures
needed to eliminate extraneous flows, and, in the interim, utilize the
temporary sanitary sewer system overflow to alleviate potential
adverse conditions.
WV Town of Winfield Amended This amendment requested a temporary SSO, actively pursued the
06/06/03 necessary processes for identifying and eliminating sources of I/I
within the Town's wastewater collection system, and requested an
extension to complete the wastewater system improvements and
cessation of the temporary SSO.
AL Arab Sewer Board (Arab
Riley Maze Creek
WWTP)
04/28/00 This Order required them to have a professional, licensed engineer
prepare a compliance plan for them to submit. The plan was to
evaluate the causes of the bypass and overflow discharges of raw
sewage at the treatment plant and make recommendations on how
to eliminate or significantly reduce the discharges. A civil penalty of
$2,300 was assessed.
AL Arab Sewer Board
(Gilliam Greek WWTP)
04/28/00 This Order required them to have a professional, licensed engineer
prepare a compliance plan for them to submit. The plan was to
evaluate the causes of the bypass and overflow discharges of raw
sewage at the treatment plant and make recommendations on how
to eliminate or significantly reduce the discharges. A civil penalty of
$1,300 was assessed.
AL CityofAttalla, Attalla
Wastewater treatment
lagoon
02/26/02 This Order required the City to pay a civil penalty of $1,200 plus
remove pollutants from their discharge during wet weather to the
maximum extent possible. Additionally, the City was required to
conduct and complete a thorough investigation of the existing
treatment works and maintenance and operating procedures of the
facility and, prepare and submit a compliance plan.
K-46
-------
Appendix K
Region State Case Name/City Name Effective Date
AL City of Cullman, Cullman Modification
WWTP 11/10/99
AL City of Cullman, Cullman 10/29/98
WWTP
Description
This Order required the City to execute the necessary contracts for
the construction of the new or additional treatment works or
modification of existing treatment works necessary to achieve
compliance.
This Order established certain deadlines for the City to achieve
compliance, which the City later requested extensions for those
deadlines due to conditions beyond its reasonable control.
AL
City of Moulton
06/19/97 This Order required the City to submit a compliance plan which
evaluated the causes of SSOs at the manhole near the intersection
of Alabama Highway 24 and 33 and the City and made
recommendations on how to eliminate or significantly reduce SSOs
and achieve compliance. They were also required to employ a
registered professional engineer to inspect the entrance bridge and
service road to determine the need for repairs and replacement to
ensure reliable access to the facilities.
AL
AL
AL
AL
City of Tuscaloosa 11 /07/01
Decatur Utilities
11/09/00
Demopolis Water Works 11/23/98
and Sewer Board, City of
Demopolis
Demopol is Water Works 08/02/01
and Sewer Board, City of
Demopolis
The Order required the City to complete the ultraviolet disinfection
project and have a substantially complete and operational
ultraviolet disinfection system at the wastewater treatment plant by
10/01/03.
The Order required them to have a registered professional engineer
prepare and submit a compliance plan which evaluated the causes
of the bypasses or overflows and made recommendations on how
to eliminate or significantly reduce the bypasses or overflows to
achieve compliance.
The Order addressed violations of the limitations established in the
Permit as indicated by the Discharge Monitoring Reports (DMRs)
submitted to the Department by the City. Interim limitations on
discharge of pollutants from Outfall 001 into the Tombigbee River
were established.
This Order rescinded the 1998 Order and required the City to pay a
civil penalty of $5,300. An engineering report investigating the
needs for changes in maintenance and operation procedures and
the need for modification of existing treatment works or the need for
any new or additional treatment works was supposed to be
submitted to the Alabama Department of Environmental Protection
(ALDEP) within three months of this Order.
AL Stevenson Utilities Board, 01/09/02
Stevenson Wastewater
Treatment Lagoon,
Stevenson
This Order required them to complete construction and start up the
new or additional treatment works or modification of existing
treatment works necessary to achieve compliance with Fecal
Coliform discharge limitations by 10/14/03. They were also required
to complete construction and start up of new pumping stations,
SCADA System and upgrade of sewage collection system by
08/30/03. Construction of any additional sewer system rehabilitation
was to be complete by 10/22/04.
AL The Water Works and
Sewer Board of the City
of Anniston, Choccolocco
Creek WWTP
06/25/98 This Order required the City to immediately make revisions to the
overflow weirs at the headworks of the WWTP and at the
Southeastern Area Lift Station to eliminate any leaking of untreated
wastewater that resulted in continuous bypasses. They were also
required to have a professional, licensed engineer prepare a report
outlining the causes of noncompliance and they were supposed to
later implement those preventative measures listed in the report.
K-47
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
AL Utilities Board of the City 08/06/97
of Athens
AL Utilities Board of the City 01/08/99
of Bayou La Batre
AL Utilities Board of the City 12/03/01
of Helena
Description
The City was required to have a professional engineer prepare a
compliance plan for the City to submit to the Department no later
than 09/30/97. The compliance plan was to evaluate the causes of
the SSO's at the cited manholes near the Athens Limestone
Hospital and the L&N Railroad overpass and make
recommendations on how to eliminate or significantly reduce the
SSO's.
The City was required to prepare and submit a Compliance Plan to
the Department for approval no later than 03/31/99. The plan will
identify causes of effluent limitations violations and describe
corrective actions, as well as provide a schedule implementing the
Compliance Plan.
The 1997 Order was rescinded. These Order required them to have
a registered professional engineer prepare and submit the plans
and specifications to upgrade the existing Helena WWTP to a 4.95
MOD. All construction was supposed to be complete by 11/30/03. In
lieu of paying the $100,000 civil penalty, they performed a
Supplemental Environmental Project (SEP) which consisted of the
construction of a new pump station in the park area.
AL Utilities Board of the City 08/22/97
of Helena
This Order to addressed 53 SSOs in 1996 at several manhole
locations in the collection system. The 53 SSO's resulted in a total
of 29,330,000 gallons of raw sewage overflow from its collection
system. They were required to submit a compliance plan schedule
to resolve the violations. They failed to meet the milestones of two
engineering activities, did not complete the replacement of the main
pumping station at the scheduled date, and failed to expand the
existing Helena WWTP to a 4.95 MGD plant.
FL South Cross Bayou
WWTF, Pinellas County,
Clearwater
04/20/94 The Order authorized the County to proceed with the corrective
actions outlined in the document and temporarily operate the
WWTP and injection well system for a period of five years. They
were also required to pursue construction and implementation of a
County regional reuse system and upgrade the Facility to Advanced
Wastewater Treatment (AWT) to include surface water discharge
for backup disposal. A stipulated penalty of $36,000 was assessed.
4 NC Belmont City-A Sludge/ 10/30/01
Lars
4 NC Mebane Bridge WWTP 01/25/02
4 NC Morrisville Town- 04/11/00
Carpenter
4 NC Murfreesboro Town 10/11/00
WWTP
4 NC Neuse Crossing WWTP 02/17/00
4 NC Pond Creek WWTP 01/25/02
4 NC SanfordWWTP 11/25/02
4 NC SanfordWWTP 07/09/03
4 NC Town of Canton 03/27/00
4 NC Town of Green Level 03/16/01
4 NC Warsaw WWTP 08/03/00
K-48
-------
Appendix K
Region State Case Name/City Name Effective Date
SC
sc
Bath and Water and
Sewer District, Aiken
County
08/21/97
Berkeley County Water 05/07/02
and Sanitation Authority,
Lower Berkely WWTF,
Berkeley County
Description
This Order required the County to clean out the sewer line within
three days of the Order and replace the section of sewer line from
the main trunk line to the edge of the property at 15 Hill Street
within four months of the Order. A $10,000 civil penalty was
suspended.
The Order required the County to submit a summary report of
corrective actions taken to prevent future unauthorized discharges.
A civil penalty of $9,900 was assessed.
SC City of Hanahan
03/20/00 The City was required in this Order to complete development of a
comprehensive CMOM program and implementation of the initial
system audit and by 09/01/00, submit a summary detailing the
findings of the initial audit. A civil penalty of $11,200 was assessed.
SC City of Hardeeville 02/28/02
SC City of Lancaster
The Order addressed the discharge of sewage into the environment
not in compliance with their permit and failure to properly operate
and maintain, at all times, all waste treatment systems. An $8,000
civil penalty was assessed.
01/27/97 This Order addressed raw sewage leaking from an exposed
polyvinyl chloride (PVC) line under a bridge and from an
abandoned line adjacent to the bridge decreased dissolved oxygen
levels below stream standards resulting in a fish kill. As a result of
this violation, the City was required to submit a schedule to survey
the collection system as well as a schedule to inspect the collection
system on a routine basis. A civil penalty of $12,000 was assessed
plus $3,061.35 for the cost of the fish kill.
SC City of Lancaster
07/31/01 The Order required the City to begin developing a Capacity,
Management, Operation, and Maintenance (CMOM) audit for the
wastewater collection system. A summary report of corrective
actions addressing deficiencies in the wastewater collection system
and ammonia-nitrogen and toxicity were also to be submitted.
SC City of Lancaster, 11/30/99
Catawba River Plant,
Lancaster County
SC City of Rock Hill/ 01/09/01
Manchester Creek
This Order addressed an unauthorized discharge caused by an
overflowing manhole. The City was required to submit a SSES
study plan outlining plans for evaluation of the deficiencies within its
sewer system.
This Order required the City to submit a corrective action plan for
compliance with the permitted discharge limits for fecal coliform. A
corrective action plan and schedule was also required to address
priority deficiencies in the wastewater collection system (pump
stations, manholes, line breaks/ deteriorations, etc.). Within six
months of the Order and every six months until the Order is closed,
they were supposed to submit a summary report of corrective
actions addressing deficiencies in the wastewater collection
system. A civil penalty of $23,000 was assessed.
K-49
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
SC City of Rock Hill/ 06/19/97
Manchester Creek
SC East Richland County 07/27/01
Public Service District,
Richland County
Description
This Order addressed, among other things, violations of the
permitted discharge limits for fecal coliform bacteria, total residual
chlorine, and total suspended solids.
The Order required the County to begin development of a CMOM
audit and to submit a corrective action plan and schedule to
address priority deficiencies in the wastewater collection system
(pump stations, manholes, line breaks/deterioration, etc.). Within
six months of the Order and every six months until the Order is
closed, the County was also supposed to submit a summary report
of corrective actions addressing deficiencies in the wastewater
collection system.
SC East Richland County
Public Service
District/Gills Creek
WWTP, Richland County
06/29/98 The Order required the County to submit an administratively
complete Preliminary Engineering Report addressing upgrade of
the effluent pump station and the elimination of the Gills Creek
discharge point. They were also required to submit an I/I study,
outlining deficiencies in the waste disposal system and a schedule
for completion of the study and of any necessary repairs.
SC McCormick County Water 07/21/03
and Sewer, McCormick
County
SC McCormick County Water 08/19/02
and Sewer, McCormick
County
This Order required the County to implement and re-evaluate the
approved MOM program, submit a schedule for lift station
inspections, submit a report of reduction of SSOs during the most
recent 12 months, and submit a schedule plan to pump out
interceptor tanks in Savannah Lakes Village including disposal
sites.
The Ordered required the County to immediately begin inspecting
all lift stations on a daily basis or have them equipped with
telemetry monitoring. The lift station inspection records were
supposed to be maintained for at least three years. Additionally, the
Order required the County to submit a report identifying the
reduction of SSOs since 01/01/00, as a result of compliance
requirements of the 1999 Consent Order, as well as submit a five
year on-going schedule to pump out interceptor tanks in Savannah
Lakes Village, and submit "Sanitary Sewer Overflow or Pump
Station Failure Forms" for unreported SSOs identified.
SC McCormick County Water 12/14/99
and Sewer, McCormick
County
The County agreed to operate and maintain the wastewater
collection system, develop and implement a CMOM program,
evaluate all lift stations and take corrective actions accordingly,
report all SSOs, and pay a penalty.
K-50
-------
Region State Case Name/City Name Effective Date
SC Spartanburg Sanitary
Sewer District/Fairforest
Plant, Spartanburg
County
06/09/99
Appendix K
Description
The Order required the County to submit a Sewer System
Evaluation Survey (SSES) study plan and later results for both,
Camp Croft collection system and Fairforest Drainage Basin. The
plans were supposed to have an implementation schedule for the
phases of the SSES. A comprehensive Management, Operation,
and Maintenance program (MOM) for the entire wastewater
collection system was also to be submitted along with a corrective
action plan detailing operation and maintenance procedures and/or
pretreatment program modifications. At civil penalty of $36,000 was
assessed.
SC Town of Carlisle 09/02/99 This Order required the Town to obtain a generator capable of
operating the lift stations during power outages, submit a SSES
study plan for the Westwood and Clearbranch subsystems along
with an implementation schedule for the phases of the SSES,
submit the results of the Phase I of the SSES, and submit a MOM
plan for the entire wastewater collection system.
SC
Town of Chesterfield
10/01/02 The Order required the Town to submit a summary of corrective
actions taken to prevent SSOs, implement temporary measures to
prevent SSOs at the high school lift stations and submit a summary
report detailing the measures taken, submit a corrective action plan
for the upgrade of the high school lift station, begin development of
CMOM audit, submit a corrective action plan and schedule to
address priority deficiencies in the wastewater collection system,
and within six months of the Order and every six months after the
Order is closed, submit a summary report of corrective actions
addressing deficiencies in the wastewater collection system.
SC Town of Fort Mill 05/03/00 The Order required the Town to begin development of a CMOM
audit and to submit a corrective action plan and schedule to
address priority deficiencies in the wastewater collection system
(pump stations, manholes, line breaks/ deterioration, etc.). Within
six months of the Order and every six months until the Order is
closed, the County was also supposed to submit a summary report
of corrective actions addressing deficiencies in the wastewater
collection system. A civil penalty of $11,200 was assessed.
SC
Town of McColl
07/22/02 The Town was required to begin development of a cMOM audit,
submit a corrective action plan and schedule to address priority
deficiencies in the wastewater collection system, and within six
months after the Order and every six months after the Order is
closed, submit a summary report of corrective actions addressing
deficiencies in the wastewater collection system.
SC Town of Pamplico
05/17/00 The Order required the Town to submit a corrective action plan
detailing measures taken or to be taken to prevent overflows. They
were also required to submit detailed reports of all I/I work
performed, including flow isolation and visual manhole inspections.
A civil penalty of $10,200 was assessed.
K-51
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
SC Town of Varnville
08/11/97
Description
The Order addressed the Town allowing unauthorized discharges
of untreated wastewater into the environment. As a result, the Town
was required to notify the Department verbally within 24 hours of a
spill and follow-up with a written description within five days. A civil
penalty of $3,500 was assessed.
4 SC Western Carolina 06/09/99
Regional Sewer Authority,
Greenville County
This Order required the County to submit a study plan for instream
water quality assessment of fecal coliform bacteria, implement the
water quality assessment for fecal coliform bacteria, submit a study
plan for a biological assessment around the collection systems, and
pay a civil penalty of $82,000.
TN Athens Utilities Board 01/05/99
TN City of Alexandria 07/19/00
TN City of Alexandria 10/02/02
TN City of Bluff City 07/28/98
The Order required the City to submit to the Chattanooga
Environmental Assistance Center (CEAC) an engineering report by
08/15/99.
The City was required to complete construction of the approved
wastewater treatment plant (WWTP) additions and/or
improvements by 08/31/01.
The City was required to complete construction of the WWTP
facility by 10/31/02. Of the total $104,000 penalty, $7,500 will be
due within one month of this Order and the remainder will be
contingent with fulfilling the remaining tasks.
This Order required the City to complete construction of the sewer
connection by 05/15/98, and complete closure of the WWTP,
without the bypass of sewage, within three months of the systems
connection to the City of Bristol Utilities. A penalty of $17,750 was
assessed, of which $2,250 was due within one month of this Order,
and the remainder was contingent upon fulfilling required tasks.
4 TN City of Church Hill 04/02/97
This Order required the City to notify the Tennessee Department of
Environment and Conservation (TNDEC) of all sewage facility
projects constructed or under construction without the Department's
approval within one month of this Order. A penalty of $5,000 was
due within one month of this Order.
4 TN City of Copperhill
10/21/99
4 TN City of East Ridge 04/29/96
4 TN City of Franklin
4 TN City of Franklin
10/26/99
11/13/00
4 TN City of Greenbrier 03/20/00
The City was required to have two adequately sized and
operational pumps installed at the City's lift station by 12/01/99, as
well as have two adequately sized and operational return activated
sludge pumps installed at the WWTP.
This Order required the City to complete the approved Corrective
Action Plan by 12/31/98. A $30,000 contingent penalty was
assessed.
The Order addressed, among other things, permit violations. The
City was required to pay a damage fee of $6,326 and a civil penalty
of $3,750.
This Order required the City to implement all remedial measures
detailed in the approved report within six months of this Order. Of
the total $57,500 civil penalty, $15,000 will be due within one month
of this Order and the remainder will be contingent of fulfilling the
remaining tasks.
This Order required the City to complete the WWTP
upgrade/expansion and interceptor improvements within nine
months of start of construction or, by 03/01/01. Of the total
$141,750 penalty, $1,500 will be due within one month of this Order
and the remainder will be contingent with fulfilling the remaining
tasks.
K-52
-------
Appendix K
Region State Case Name/City Name Effective Date
TN City of Harriman
06/28/00
TN City of Harriman
07/23/02
TN City of Jefferson City 06/04/01
TN City of Jellico 10/03/97
TN City of Kingston
11/30/01
TN City of Lafayette
TN City of LaVergne
TN City of LaVergne
04/22/03
11/08/99
10/24/00
4 TN City of Lawrenceburg 11/19/98
4 TN City of Lawrenceburg 03/27/01
4 TN City of Middleton 11/10/98
4 TN City of Middleton 08/25/00
Description
This Order required the City to complete the WWTP
upgrade/expansion and interceptor improvements within 14 months
of start of construction or, by 03/01/03. Of the total $266,250
penalty, $30,000 will be due within one month of this Order and the
remainder will be contingent with fulfilling the remaining tasks.
The City was required to complete construction of Woodyard Pump
Station/Force Main by 06/31/03, complete
construction/rehabilitation of the South Harriman Pump Stations by
12/15/03, and complete construction of WWTP project by 03/01/04.
A penalty of $30,000 will be due within one month of this Order.
The City was required to complete construction of the WWTP
improvement project by 01/31/02.
This Order required the City to complete collection system repairs
and treatment plant upgrades/ expansion, and implement an
ongoing program for collection system rehabilitation. Of the total
$11,500 penalty, $1,500 will be due within one month of this Order
and the remainder will be contingent with fulfilling the remaining
tasks.
This Order required the City to complete the implementation of the
Corrective Action Plan and within three months of complete
implementation, the City will be in full compliance with its NPDES
permit. Of the total $207,000 penalty, $5,000 will be due within one
month of this Order and the remainder will be contingent with
fulfilling the remaining tasks.
The City was required to complete construction of the WWTP
upgrade. Of the total $92,500 penalty, $7,500 will be due within one
month of this Order and the remainder will be contingent with
fulfilling the remaining tasks.
This Order addressed the discharge of wastewater and raw sewage
overflowing from manholes. A civil penalty fee of $2,500 will be due
within one month of this Order.
The Order addressed, among other things, permit violations. A civil
penalty fee of $2,000 will be due within one month of this Order.
This Order required the City to complete repairs to the WWTP and
collection system by 02/15/99.
This Order required the City to complete the installation of the new
sludge filter belt press in the WWTP by 03/01/01. A penalty fee of
$9,375 will be due within one month of this Order..
The Order required the City to complete construction by 09/30/00.
The Order required the City to complete construction of the
proposed upgrades to the existing lagoon, the modifications to the
force main, and the replacements of the effluent pumps.
Additionally, within six months of this Order, the City will complete
construction of the parallel force main. Of the total $47,750 penalty,
$5,000 will be due within one month of this Order and the
remainder will be contingent with fulfilling the remaining tasks.
K-53
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
4 TN City of Murfreesboro 08/21/99
4 TN City of Murfreesboro 05/22/01
4 TN City of Portland Public 08/02/02
Works
4 TN City of Pulaski
05/08/98
4 TN City of Red Bank 02/25/97
4 TN City of Rockwood 10/29/98
4 TN City of Sparta
Description
The City was required to complete the expansion of the sewer
treatment plant and place the sewer treatment plant into full
operation by 01/31/00. As a result, the Town was charged a
damage fee of $12,107 in addition to the penalty of $400,000. Of
the total penalty, $50,000 was due within one month of this Order
and the remainder was to be contingent upon fulfilling the required
tasks.
The Order requested that the City perform a Supplemental
Environmental Project (SEP) in lieu of paying the $50,000 civil
penalty. The City was to purchase a five acre lot, which had a
wetland and protect, in perpetuity, the aesthetic, educational, or
ecological values of this wetland.
The Order addressed discharges into waters of the U.S. without a
NPDES permit and causing a condition of pollution that resulted in
a fish kill. The damage fee totaled $541.11 and the penalty fee
totaled $5,000.
The Order required the City to submit to the Division of Water
Pollution Control a plan to eliminate permit limit violations by
06/15/98.
The Order required the City to implement and complete the
approved 1997 Sewer Rehabilitation and Corrective Action Plan
and, if necessary, additional collection system improvements by
09/30/01. Of the total $164,500 penalty, $10,000 will be due in
increments by 09/01/97.
This Order required the City to complete the Corrective Action Plan
and obtain full compliance with its NPDES permit by 08/01/01. Of
the total $16,750 penalty assessed, $1,500 was due within one
month of this Order and the remainder was to be contingent upon
fulfilling required tasks.
10/04/00 The Order required the City to submit a report evaluating the
effectiveness of the WWTP upgrade/expansion. Additionally, the
city was required to submit a Corrective Action Plan to address the
collection system I/I problems. Of the total $62,000 penalty, $7,500
will be due within one month of this Order and the remainder will be
contingent with fulfilling the remaining tasks.
4 TN City of Watertown 02/08/00
4 TN City of Watertown 06/03/03
4 TN Knoxville Utilities Board 05/20/03
4 TN Lenoir City Utilities Board 01/03/01
TN Lynnwood Utility No date
Corporation provided
This Order addressed effluent discharge violations. A civil penalty
of $1,100 will be due within one month of this Order.
This Order required the City to complete construction of the
wastewater collection system and WWTP improvements by
08/31/03. Of the total $87,500 penalty, $10,500 will be due in
increments by 03/31/04.
This Order required a Phase I Corrective Action Plan/Engineering
Report to be submitted within ten months of receiving comments
from the Department. A Phase II Corrective Action
Plan/Engineering Report was required to be submitted by 06/30/06.
A contingent penalty was assessed at $475,000.
This Order required the Board to complete collection system
improvements by 07/31/01 and to complete all planned WWTP
improvements by 12/31/01. They were also required to complete
construction of approved additions and/or improvements within 18
months of start of construction or, by 06/30/05.
The Order addressed permit violations. A civil penalty of $5,000 will
be due within one month of this Order.
K-54
-------
Appendix K
Region State Case Name/City Name Effective Date
4 TN Metropolitan Government 09/17/99
of Nashville and
Davidson County
Description
The City and County were required to have all CSO controls,
including but not limited to, floatable material and debris removal,
combined sewage storage and/or detention and CSO elimination, in
place by 07/01/01. The City and County were also supposed to
eliminate all overflows or bypassing from its sanitary sewers to all
waters of the state by 07/01/01. Of the total $600,000 penalty
assessed, $100,000 was due within one month of this Order.
However, the City and County had the option to perform a SEP in
lieu of paying the $100,000.
TN Town of Collierville 06/03/98
The Town was required to complete the installation of the new
return sludge pumping system within three months of this Order.
They were also required to complete the new aerated lagoon
treatment plant within two months of this Order. Of the total
$118,500 penalty, $5,000 was due within one month of this Order
and the remainder was contingent with fulfilling the remaining tasks.
4 TN Town of Gainesboro 11/22/00
4 TN Town of Gainesboro 03/27/01
4 TN Town of Monterey 09/11/02
TN Town of Mosheim 04/25/01
TN Town of Pikeville
01/09/00
The Order required the Town to complete construction on the
WWTP upgrade/expansion by 09/01/02. Of the total $67,625
penalty, $6,500 will be due within one month of this Order and the
remainder will be contingent of fulfilling the remaining tasks.
This Order required the Town to complete construction on the
WWTP upgrade/expansion by 03/01/03. A penalty of $5,500 will be
due within one month of this Order.
The Town was required to complete the implementation of the
Corrective Action Plan and obtain full compliance with its NPDES
permit within three years of approval. As a result, the Town was
charged a damage fee of $6,413 in addition to the penalty of
$115,500. Of the total penalty, $12,500 was be due within one
month of this Order and the remainder was to be contingent upon
fulfilling required tasks.
The Order required the Town to complete construction on the
WWTP upgrade/ expansion by 06/01/01 and complete the l&l
rehabilitation by 12/31/01. A civil penalty of $3,000 will be due
within one month of this Order.
This Order required the Town to submit a pretreatment program for
approval and, within one year of this Order, be in compliance with
its NPDES permit. Of the total $58,250 penalty, $4,125 will be due
within one month of this Order and the remainder will be contingent
with fulfilling the remaining tasks.
TN Town of Spring City 07/31/03
The Order required the Town to submit a plan for approval to
comply with permit requirements and within 12 months of approval,
the plan will be implemented. Of the total $15,000 penalty, $5,000
will be due within one month of this Order and the remainder will be
contingent with fulfilling the remaining tasks.
TN Town of Spring Hill 06/04/99
TN Town of Spring Hill 01/26/00
The Town was required to implement a plan to prevent any future
bypassing in the Pipkin Hills subdivision area by 09/01/99.
The Order required the Town to complete the Corrective Action
Plan and obtain full compliance with its NPDES permit by 01/01/01.
Of the total $73,312 penalty, $1,312 will be due within one month of
this Order and the remainder will be contingent with fulfilling the
remaining tasks.
K-55
-------
Report to Congress on Impacts and Control of CSOs and SSOs
Region State Case Name/City Name Effective Date
Description
IN
IN
City of Batesville
City of Brazil
03/23/01
12/09/93;
Amended 10/95
5 IN City of Brazil 12/07/99
5 IN City of Charlestown 04/03/02
5 IN City of Dunkirk 05/28/93
5 IN CityofElwood 10/04/93
5 IN City of Garrett 12/13/02
5 IN City of Gas City 03/25/91
5 IN City of Gas City 11/07/02
5 IN City of Greencastle 05/11/99
5 IN City of Greenwood 07/25/97
5 IN City of Indianapolis
5 IN City of Jasonville 12/20/93
Referred to EPA 08/20/02.
The City was required to submit a Compliance Plan, including a
schedule with fixed dates for each milestone and a reasonable date
for final compliance. They were also required to initiate the work
detailed in the plan within 30 days of being fully approved and
complete the work according to the plan's schedule.
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN City of Lawrence
City of Madison
City of New Albany
City of Portland
City of Rockport
City of Salem
City of Salem
City of Scottsburg
Community University of
Gary
Henryville
Town of Advance
Town of Albany
Town of Ashley
Town of Austin
Town of Bristol
Town of Brooklyn
Town of Carthage
Town of Cedar Lake
Town of Churubusco
Town of Clay City
Town of Converse
Town of Cumberland
Town of Dillsboro
IN Town of Elizabethtown
IN Town of Farmersburg
01/04/99;
Amended
9/26/00
12/10/97
05/09/97
03/30/93
01/29/03
09/18/96
08/18/98
07/23/03
08/07/91
10/31/01
07/28/03
11/30/00
09/11/01
05/11/98
11/10/98
10/20/98
01/12/99
03/04/99
06/24/03
03/05/02
02/23/99
02/01/02
05/01/03
11/27/91;
Amended
05/20/98
08/08/02
The City was required to develop and submit to IDEM its
Compliance Plan for IDEM approval.
The Town was required to submit a Compliance Plan detailing the
construction of the new oxidation ditch wastewater treatment
system, including an implementation and construction schedule
within three months of this Order.
K-56
-------
Appendix K
Region State Case Name/City Name Effective Date
Description
IN
IN
IN
IN
IN
Town of Farmland
Town of Flora
Town of Fort Branch
Town of Fountain City
Town of French Lick
05/09/03
04/30/92;
Amended
06/20/03
03/23/01
09/30/02
11/12/93
The Town was required to develop and submit to Indiana
Department of Environmental Management (IDEM) for approval a
Compliance Plan which identified actions the Town was to take in
order to achieve compliance within six months of this Order. This
included eliminating sewer system overflows (SSOs).
This Order required the Town to complete construction of its I/I
removal project by 12/21/94, complete construction of its sewage
treatment plant by 06/30/97, and complete the necessary actions to
assure that the downspouts and the sump pumps do not connect
with the sewage treatment plant.
IN
Town of Galveston
07/02/02 The Town was required to immediately implement the approved
Compliance Plan and adhere to the milestone dates.
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
Town of Geneva
Town of Grabill
Town of Grandview
Town of Greentown
Town of Hanover
Town of Hartsville
Town of Haubstadt
Town of Jonesboro
Town of LaGrange
Town of Lapel
Town of Leavenworth
Town of Lynnville
Town of Milan
Town of Montpelier
Town of Moores Hill
Town of Mt. Etna
Town of Mulberry
Town of New Providence
Town of Palmyra
Town of Paoli
04/29/03
02/07/02
01/21/99
03/18/98
03/07/01
01/27/00
08/1 0/94
06/17/94
03/18/98
11/21/97
07/23/01
07/28/03
05/22/98
09/20/93
09/26/00
11/16/98
10/18/98
12/28/98
01/02/01
05/12/97
5 IN Town of Parker City
5 IN Town of Parker City
5 IN Town of Pierceton
5 IN Town of Remington
5 IN Town of Riley
5 IN Town of Rockville
5 IN Town of Rome City
5 IN Town of Santa Glaus
05/23/94
01/02/01
11/18/98;
Amended
06/24/03
06/06/03
12/12/02
07/22/97
05/12/00
06/01/01
The Town was required to submit to IDEM a Compliance Plant
which included an implementation schedule.
This Order required the City to develop and submit to IDEM its
Compliance Plan for IDEM approval.
The Town was required to complete sludge handling improvements
to assure NPDES compliance, complete a Sewer System
Evaluation Study (SSES), and submit a list of I/I sources found and
corrected.
K-57
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
Region
5
5
5
5
5
5
5
5
5
5
6
State
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
LA
Case Name/City Name
Town of Schererville
Town of Sellersburg
Town of Staunton
Town of Sweetser
Town of Trafalgar
Town of Upland
Town of Upland
Town of West College
Corner
Town of Whitestown
Town of Wolcottville
City of Pineville
Effective Date
08/15/91
12/14/00
09/26/00
01/29/02
01/26/95
06/06/94;
Amended 12/01
01/12/01
12/18/97
05/01/01
06/20/02
05/31/02
Description ^^1
The Town was required to develop and submit to IDEM a
Compliance Plan for approval.
Later referred to EPA.
The Order required them to submit a comprehensive plan for the
LA
LA
City of Ruston
City of Ruston
12/16/99
05/31/01
expeditious elimination and prevention of non-complying discharges
and complete a written report to include a detailed description of the
circumstances of the violations, the actions taken to achieve
compliance, and corrective or remedial actions taken to mitigate
any damages.
Under this Order, they were required to cease all unauthorized
discharges, meet and maintain compliance with their Permit, submit
a written report to include a detailed description of the
circumstances for the violations and the actions taken to achieve
compliance, and to submit a schedule for corrections.
This Order required them to immediately cease unauthorized
discharges to the waters of the state or any unenclosed areas that
drain to the waters of the state, submit a comprehensive plan for
the expeditious elimination and prevention of the noncomplying
discharges, complete a written report to include a detailed
description of the circumstances for the violations, the actions taken
to achieve compliance, and any corrective or remedial actions
taken.
LA
LA
LA
LA
City of Ruston
City of Ruston
City of Ruston
City of Ruston
LA
City of Westwego
Amendment The Order required the City to complete repairs/replacement of
11/29/2001 U.S. Highway 80 East force main by 06/15/02, complete
rehabilitation of the clarifiers by 01/15/03, and complete
construction of the WWTF/pump station/ force main by 12/31/06.
07/11/97 This Order required the City to immediately cease all unauthorized
discharges from the facility to the waters of the state, submit a
comprehensive plan for the expeditious elimination and prevention
of noncomplying discharges, and submit a completed Louisiana
permit application.
04/29/98 This Order addressed the discharge of inadequately treated
sanitary wastewater.
12/16/99 This Order required the City to submit a written report detailing the
circumstances for the violations, actions taken to achieve
compliance, and corrective or remedial actions taken to mitigate
damages. They were also required to submit a comprehensive plan
for the expeditious elimination and prevention of noncomplying
discharges.
04/27/98 This Order addressed the City's O&M deficiencies, sampling
deficiencies, and violations of effluent limitations.
K-58
-------
Appendix K
Region State Case Name/City Name Effective Date
6
LA City of Westwego
04/24/01
LA
City of Westwego
08/29/02
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
LA
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
City of Westwego
Bethany/Warr Acres
Public Works Authority
Bixby Public Works
Authority
Bixby Public Works
Authority
Blackwell Municipal
Authority
Bokoshe Public Works
Authority
Carney Public Works
Authority
Checotah Public Works
Authority
Checotah Public Works
Authority
Chouteau Public Works
Authority
City + A1 53 of McAlester
City of Ada
City of Altus
City of Apache
City of Ard more
City of Atoka
City of Bartlesville
City of Bethany
City of Blackwell
City of Broken Bow
12/24/02
03/09/00
Closed
05/23/02
06/01/98
Closed
1 2/1 7/99
Closed
10/01/95
Closed
04/11/97
Closed
12/01/99
Closed
03/08/01
Closed
06/14/95
Closed
11/30/00
Closed
12/01/99
Closed
01/11/94
Closed
07/12/93
Closed
06/12/02
Description
This Order addressed the City's the violation of effluent limitations,
operation and maintenance requirements, and self-monitoring
programs. The Order required them to immediately cease
unauthorized discharges to the waters of the state, submit a written
report to include the circumstances for the violations, and submit a
comprehensive plan for the elimination and prevention of such non-
complying discharges.
This Order required them to immediately cease unauthorized
discharges to the waters of the state, submit semi-annual progress
reports until completion of proposed improvements, and to
complete a written report to include a detailed description of the
circumstances for the violations, the actions taken to achieve
compliance, and corrective or remedial actions taken to mitigate
any damages resulting from the violations.
This Order addressed the City's failure to properly operate and
maintain its facility.
This Order addressee bypasses of untreated wastewater.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed unpermitted bypasses.
This Order addressed discharges without a permit. The Authority
was required to complete construction of the new collection system
by 01/01/04.
This Order addressed exceeding discharge limits.
This Order addressed discharges without a permit.
This Order addressed discharge violations.
This Order addressed violation of discharge permit.
This Order addressed discharges without a permit.
This Order addressed the City discharging without a permit.
This Order addressed unpermitted discharges.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed unauthorized bypasses.
This Order addressed discharges without a permit. The City was
required to complete construction of the lift station upgrades by
04/01/03.
This Order addressed failure to report bypasses.
This Order addressed discharges without a permit.
K-59
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
1 Region
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
State
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Case Name/City Name
City of Bulter
City of Chandler
City of Claremore
City of Claremore
City of Cleveland
City of Clinton
City of Clinton
City of Cordell
City of Corn
City of Coweta
City of Davis
City of Del City
City of Durant
City of Durant
City of Durant
City of El Reno
City of El Reno
City of El Reno
City of El Reno
City of El Reno
City of El Reno
City of El Reno
City of Elgin
City of Elk City
City of Elk City
City of Elmore City
City of Enid
City of Enid
City of Fairview
City of Fairview
City of Glenpool
City of Guthrie
Effective Date
07/28/99
Closed
07/26/99
Closed
1 0/1 0/94
Closed
12/01/99
Closed
10/16/98
Closed
04/11/97
Closed
1 2/1 5/99
Closed
11/19/98
Closed
01/26/96
Closed
10/10/95
Closed
04/24/00
Closed
11/16/00
Closed
07/10/95
Closed
07/10/95
Closed
08/01/97
Closed
02/1 3/97
Closed
10/01/95
Closed
10/21/02
02/05/01
Closed
06/12/01
Closed
07/10/95
Closed
05/19/95
Closed
03/06/01
Closed
Description ^^1
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed violation of discharge permit.
This Order addressed violation of discharge permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed unpermitted bypass from manholes.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed unpermitted bypasses.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed unreported sewage bypasses.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed exceeding discharge limits.
This Order addressed exceeding discharge limits.
This Order addressed discharges without a permit. The City was
required to complete construction on the collection system
upgrades by 12/01/03.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharge violations.
This Order addressed violation of discharge permit.
This Order addressed exceeding discharge limits.
This Order addressed bypasses.
K-60
-------
Appendix K
1 Region
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
State
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Case Name/City Name
City of Haileyville
City of Haileyville
City of Hartshorne
City of Healdton
City of Heavener
City of Heavener
City of Henryetta
City of Henryetta
City of Henryetta
City of Hobart
City of Hobart
City of Holdenville
City of Holdenville
City of Holdenville
City of Hollis
City of Hooker
City of Hugo
City of Hugo
City of Hugo
City of Hugo
City of Idabel
City of Kingfisher
City of Kingfisher
City of Konawa
City of Lawton
Effective Date
03/1 5/99
Closed
08/27/96
Closed
02/22/96
Closed
08/01/02
05/25/99
Closed
05/25/99
Closed
07/11/95
Closed
1 0/1 0/95
Closed
11/07/02
05/30/97
Closed
07/11/95
Closed
12/01/99
Closed
10/29/01
Closed
09/25/98
Closed
02/01/00
Closed
08/14/98
Closed
06/21/00
Closed
07/01/96
Closed
12/17/01
Closed
11/14/95
Closed
01/17/03
Description ^^1
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed bypass from manhole.
This Order addressed discharges without a permit. The City was
required to complete construction on the collection system
upgrades by 12/01/03.
This Order addressed discharge of sewer, failure to sample, and
bypassing.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit. The City was
required to complete construction of improvements at the Heritage
Village by 09/01/03, and complete construction of improvements to
eliminate the connections between the storm sewer and the
sanitary sewer systems within 12 months of obtaining adequate
funding.
This Order addressed discharges without a permit.
This Order addressed discharges of sewage effluent.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
The City was required to complete construction/rehabilitation of
Phase I by 07/01/05, and complete the flow monitoring assessment
for Phase I by 01/01/06. The City was also required to complete
construction/rehabilitation of Phase II by 07/01/12, and complete
the flow monitoring assessment for Phase II by 01/01/13.
OK City of Lawton
This Order addressed discharges without a permit.
K-61
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
1 Region
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
State
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Case Name/City Name
City of Madill
City of Marland
City of McAlester
City of McAlester
City of McAlester
City of Minco
City of Moore
City of Moore
City of Morris
City of Noble
City of Noble
City of Norman
City of Nowata
City of Nowata
City of Oklahoma City
City of Oklahoma City
City of Okmulgee
City of Okmulgee
City of Okmulgee
City of Okmulgee
City of Okmulgee
City of Owasso
City of Pawhuska
City of Pawhuska
City of Pawhuska
City of Pawnee
City of Pawnee
City of Picher
City of Piedmont
City of Ponca
City of Poteau
City of Poteau
Effective Date
08/27/96
Closed
1 0/1 0/95
Closed
04/1 5/98
Closed
07/11/95
Closed
07/11/95
Closed
10/01/95
Closed
07/11/95
Closed
05/24/96
Closed
05/18/01
Closed
03/21/01
Closed
09/23/97
Closed
06/20/01
Closed
04/17/00
Closed
11/01/01
Closed
09/07/01
Closed
09/15/97
Closed
10/01/95
Closed
12/01/99
Closed
1 0/1 0/95
Closed
09/26/00
Closed
Description ^^1
This Order addressed the inadequate facility to treat sewage
effluent.
This Order addressed discharge permit violations.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed the discharge of sewage effluent to Buggy
Creek.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed failure to obtain a discharge permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed bypass violations.
This Order addressed discharges without a permit.
This Order addressed unpermitted bypasses.
This Order addressed discharges without a permit.
This Order addressed noncompliance with discharge procedures.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed bypass of untreated wastewater from
manholes.
This Order addressed discharges without a permit.
This Order addressed unpermitted bypasses.
This Order addressed discharges without a permit.
This Order addressed sewage bypasses.
This Order addressed exceedings of discharge limits.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed sewage treatment discharges.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
K-62
-------
Appendix K
1 Region
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
State
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Case Name/City Name
City of Poteau
City of Sand Springs
City of Sand Springs
City of Sapulpa
City of Sapulpa
City of Seminole
City of Seminole
City of Spencer
City of Stillwater
City of Sulphur
City of Sulphur
City of Tonkawa
CityofValliant
City of Watonga
City of Waynoka
City of Weleetka
City of Wetumka
City of Wetumka
City of Wetumka
City of Wetumka
City of Wetumka
City of Wewoka
City of Wewoka
City of Wewoka
City of Wewoka
City of Wilburton
City of Wilson
City of Wilson
City of Woodward
City of Woodward
Effective Date
1 0/1 0/95
Closed
05/03/01
Closed
11/10/94
Closed
06/20/00
Closed
09/26/02
03/15/01
Closed
04/12/01
Closed
10/16/00
Closed
07/11/95
Closed
10/03/97
Closed
05/31/95
Closed
06/21/00
Closed
1 0/1 0/95
Closed
1 0/07/99
Closed
1 0/07/99
Closed
02/08/02;
Amended
10/14/02
07/11/95
Closed
07/11/95
Closed
Description ^^1
This Order addressed discharges without a permit.
This Order addressed unpermitted bypasses.
This Order addressed unpermitted bypasses.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit. The City was
required to complete construction of the collection system
improvements by 04/01/03.
This Order addressed discharges without a permit.
This Order addressed eliminating defects contributing to bypasses.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed violations of discharge permit.
This Order addressed, among other things, bypasses.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed violations of discharge permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed bypasses.
This Order addressed violations of discharge.
This Order addressed discharges without a permit. The City was
required to complete the previously approved Environmental
Enhancement Project (EEP) by 04/01/04, and complete
construction of the approved wastewater treatment facility (WWTF)
Number S-20104 and associated lift stations at Facility Numbers S-
20103 and S-20105 by 11/01/04.
This Order addressed violations of discharge permit.
This Order addressed violations of discharge permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
K-63
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
1 Region
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
State
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Case Name/City Name
City of Woodward
City of Wynnewood
Delaware Public Works
Authority
Fairfax Public Works
Authority
Fairfax Public Works
Authority
Grand Lake Public Works
Authority
Grand Lake Public Works
Authority
Green Country Sewer
Company
Haskell County Water
Company
Haskell Public Works
Authority
Heavener Public Works
Authority
Helena Public Works
Authority
Hinton Public Works
Authority
Hominy Public Works
Authority
Hugo Municipal Authority
Hugo Municipal Authority
Hugo Municipal Authority
Hulbert Public Works
Authority
Jay Utilities Authority
Jay Utilities Authority
Jay Utilities Authority
Jenks Public Works
Authority
Jenks Public Works
Authority
Jenks Public Works
Authority
Keota Public Works
Authority
Krebs Utilities Authority
Lakeland Water System
Marietta Public Works
Authority
Marietta Public Works
Authority
Marietta Public Works
Authority
Effective Date
10/01/95
Closed
07/10/95
Closed
12/20/99
Closed
10/10/95
Closed
12/01/99
Closed
05/26/95
Closed
06/04/97
Closed
01/11/01
Closed
07/11/95
Closed
07/11/95
Closed
04/05/94
Closed
04/14/00
Closed
07/11/95
Closed
12/01/99
Closed
10/01/95
Closing
08/04/93
Closed
10/10/95
Closed
07/11/95
Closed
06/10/99
Closed
11/14/99
Closed
10/1 6/93 Closed
10/1 6/93 Closed
06/1 9/98
Closed
This
This
This
This
This
This
This
This
This
This
This
This
This
This
This
This
This
This
This
This
This
This
This
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Description ^^1
discharges without a permit.
discharges without a permit.
discharges without a permit.
violation of discharge permit.
discharges without a permit.
discharges without a permit.
discharges without a permit.
discharges without a permit.
discharges without a permit.
discharges without a permit.
discharges without a permit.
discharges without a permit.
lagoon sewage effluent.
discharges without a permit.
bypassing collection system.
bypassing untreated sewage.
unpermitted bypasses.
discharges without a permit.
discharges without a permit.
discharges without a permit.
permit violations.
discharges without a permit.
the inadequate facility to treat sewage
effluent.
This
This
Order addressed
Order addressed
discharges without a permit.
the inadequate facility to treat sewage
effluent.
This
This
This
This
This
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
discharges without a permit.
discharges without a permit.
unpermitted discharges.
discharges without a permit.
discharge permit violations.
K-64
-------
Appendix K
1 Region
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
State
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Case Name/City Name
Muskogee Municipal
Authority
Muskogee Municipal
Authority
Muskogee Municipal
Authority
Ochelata Utilities
Authority
Okay Public Works
Authority
Okemah Public Works
Authority
Okemah Public Works
Authority
Okemah Utilities Authority
Owasso Public Works
Authority
Panama Public Works
Authority
Pensacola Public Works
Authority
Pocola Municipal
Authority
Pocola Municipal
Authority
Pocola Municipal
Authority
Quinton Public Works
Authority
Regional Metropolitan
Utility Authority
Ringling Municipal
Authority
Sapulpa Municipal
Authority
Sapulpa Public Works
Authority
Savanna Public Works
Savanna Public Works
Authority
Savanna Public Works
Authority
South Coffeyville Public
Works Authority
Stroud Utilities Authority
Tahlequah Public Works
Authority
Town + A304 of Freedom
Town of Achille
Town of Alderson
Effective Date
07/15/98
Closed
07/11/95
Closed
1 0/06/00
Closed
01/26/00
Closed
07/11/95
Closed
10/04/01
Closed
08/24/99
Closed
1 0/02/02
11/22/94
Closed
07/11/95
Closed
07/11/95
Closed
1 0/1 0/95
Closed
12/21/00
Closed
10/10/95
Closed
12/21/00
Closed
09/23/97
Closed
08/27/96
Closed
12/09/98
Closed
This
This
This
Order addressed
Order addressed
Order addressed
Description
discharges without a permit.
chronic bypasses.
the inadequate facility to treat
^^^m
sewage
effluent.
This
This
This
This
This
This
This
This
This
This
This
This
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
systems overflows and bypasses.
unpermitted bypasses.
discharges without a permit.
discharges without a permit.
unpermitted bypasses.
discharges without a permit.
unpermitted bypasses.
discharges without a permit.
unpermitted bypasses.
discharges without a permit.
discharges without a permit.
the inadequate facility to treat
sewage
effluent.
This
This
This
This
This
This
This
This
This
This
This
This
This
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
Order addressed
discharge violations.
violations of discharge permit.
discharges without a permit.
discharges without a permit.
discharges without a permit.
bypasses/permit limits.
discharges without a permit.
discharges without a permit.
violations of discharge permit.
discharges without a permit.
unpermitted bypasses.
the Town discharging without
the Town discharging without
a permit.
a permit.
K-65
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
1 Region
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
State
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Case Name/City Name
Town of Alex
Town of Antlers
Town of Antlers
Town of Antlers
Town of Antlers
Town of Antlers
Town of Arapaho
Town of Arkoma
Town of Atoka
Town of Blair
Town of Bokoshe
Town of Boswell
Town of Boynton
Town of Cad do
Town of Canute
Town of Canute
Town of Chelsea
Town of Cimarron City
Town of Copan
Town of Covington
Town of Crescent
Town of Dacoma
Town of Davenport
Town of Deer Creek
Town of Deer Creek
Town of Devol
Town of Dill City
Town of Dougherty
Town of Dougherty
Town of East Duke
Town of Fairmont
Town of Fargo
Effective Date
10/01/95
Closed
09/20/95
Closed
12/01/99
Closed
03/10/00
Closed
09/14/00
Closed
08/15/00
Closed
1 0/23/96
Closed
11/22/94
Closed
04/20/95
Closed
06/23/99
Closed
07/27/99
Closed
07/10/95
Closed
10/10/01
Closed
05/18/95
Closed
07/18/94
Closed
07/10/95
Closed
07/10/95
Closed
11/07/00
Closed
08/17/01
Closed
10/01/95
Closed
12/01/99
Closed
10/10/95
Closed
1 0/03/95
Closed
Description ^^1
This Order addressed, among other things, the Town discharging
without a permit.
This Order addressed bypasses/discharges without a permit.
This Order addressed bypass and discharge violations.
This Order addressed unpermitted bypasses.
This Order addressed unpermitted bypasses.
This Order addressed unpermitted bypasses.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed unpermitted bypasses.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed violation of discharge permit.
This Order addressed unpermitted bypasses.
This Order addressed discharges without a permit.
This Order addressed discharge permit violations.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed violation of discharge permit.
This Order addressed discharges without a permit.
K-66
-------
Appendix K
1 Region
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
State
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Case Name/City Name
Town of Freedom
Town of Freedom
Town of Ft. Towson
Town of Gans
Town of Garvin
Town of Geronimo
Town of Gore
Town of Inola
Town of Jennings
Town of Jet
Town of Keota
Town of Kingston
Town of Kingston
Town of Kiowa
Town of Krebs
Town of Kremlin
Town of Lamont
Town of Langston
Town of Lone Wolf
Town of Mannford
Town of Maud
Town of Meeker
Town of Meeker
Town of Muldrow
Town of Muldrow
Town of Nash
Town of Okarche
Town of Okarche
Town of Oktaha
Town of Panama
Town of Panama
Town of Panama
Effective Date
09/17/99
Closed
07/10/95
Closed
12/01/99
Closed
05/30/00
Closed
1 0/1 3/99
Closed
12/01/99
Closed
07/11/95
Closed
09/14/92
Closed
01/18/00
Closed
1 0/06/94 Closed
1 0/06/94 Closed
09/12/97
Closed
09/04/01
Closed
01/09/03
12/01/99
Closed
04/11/95
Closed
04/1 0/92
Closed
06/06/97
Closed
04/04/00
Closed
07/11/95
Closed
07/11/95
Closed
07/11/95
Closed
Description ^^1
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed unpermitted bypasses.
This Order addressed discharges without a permit.
This Order addressed the exceeding discharge limits.
This Order addressed violation of discharge permit.
This Order addressed discharges without a permit.
This Order addressed bypasses and discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed unpermitted bypasses.
This Order addressed discharges without a permit. The City was
required to complete construction of the upgrades to the
wastewater treatment plant within 14 months from the start of
construction.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed bypassing.
This Order addressed the inadequate facility to treat sewage
effluent.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed plant overload, no operator, and discharges.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed violations of discharge permit.
K-67
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
1 Region
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
State
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Case Name/City Name
Town of Pond Creek
Town of Quinton
Town of Quinton
Town of Ralston
Town of Ratliff City
Town of Salina
Town of Salina
Town of Salina
Town of Skiatook
Town of Soper
Town of Soper
Town of Soper
Town of Soper
Town of Spiro
Town of Spiro
Town of Springer
Town of Temple
Town of Tipton
Town of Tryon
Town of Wakita
Town of Wanette
Town of Wanette
Town of Wanette
Town of Washington
Town of Wayne
Town of Wayne
Town of Wayne
Town of Wellston
Town of Wellston
Town of Wister
Effective Date
09/12/95
Closed
09/14/99
Closed
06/11/96
Closed
12/05/00
Closed
10/20/99
Closed
11/21/01
Closed
07/11/95
Closed
12/01/99
Closed
1 0/1 0/95
Closed
08/10/01
Closed
07/06/00
Closed
11/25/96 Closed
02/22/00
Closed
12/01/99
Closed
03/11/97
Closed
09/19/94
Closed
01/12/01
Closed
12/01/99
Closed
10/10/95
Closed
12/09/98
Closed
10/10/95
Closed
03/15/94
Closed
03/15/94
Closed
02/01/87
Closed
Description ^^1
This Order addressed violations of discharge permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed unpermitted bypasses.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed violations of discharge permit.
This Order addressed the inadequate facility to treat sewage
effluent.
This Order addressed violations of discharge permit.
This Order addressed bypass of raw sewage.
K-68
-------
Appendix K
1 Region
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
9
State
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
CA
Case Name/City Name
Town of Wister
Town of Wright City
Tulsa Metropolitan Utility
Authority
Tulsa Metropolitan Utility
Authority
Tulsa Metropolitan Utility
Authority
Valliant Public Works
Authority
Wagoner Public Works
Authority
Wagoner Public Works
Authority
Warner Utilities Authority
Warner Utilities Authority
Warr Acres Public Works
Authority
Warr Acres Public Works
Authority
Weleetka Public Works
Authority, City of
Weleetka
Wilburton Public Works
Authority
Wright City Public Works
Authority
Wright City Public Works
Authority
City of Chico, Central
Valley Region
Effective Date
07/06/00
Closed
01/08/02
Closed
08/20/91
Closed
08/08/98
Closed
07/19/96
Closed
06/04/93
Closed
07/01/93
Closed
07/01/93
Closed
10/14/02
1 0/1 0/95 Closed
10/01/95
Closed
01/25/99
Closed
2000
Description ^^1
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed violations of discharge permit.
This Order addressed discharges without a permit.
This Order addressed infiltration problems and bypasses.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit.
This Order addressed discharges without a permit. The City was
required to complete construction of the collection system
improvements by 12/01/03.
This Order addressed violations of discharge permit.
This Order addressed violations of discharge permit.
This Order addressed violations of discharge permit.
The Order required the City to submit a detailed workplan and
timeline which were supposed to include dates for submission of
progress reports and for completion of the Supplemental
Environmental Project (SEP). A $50,000 civil liability penalty was
assessed.
CA City of Crescent City, 2000
North Coast Region
CA City of Folsom, Central 2000
Valley Region
CA City of Los Angeles, Los 2000
Angeles Region
This Order established a schedule for the City to complete the long-
term planning process to provide adequate wastewater treatment
capacity.
This Order addressed discharges of pollutants without waste
discharge requirements. A civil liability penalty of $70,000 was
proposed.
This Order required the City to upgrade sewers in the Hyperion
service area, such upgrades included: implement the corrective
measures for Boyle Heights and Silver Lake, construct the North
Hollywood Interceptor Sewer, the North Outfall Relief Sewer (NOS)-
East Central Interceptor Sewer (ECIS), the Northeast Interceptor
Sewer (NEIS) - Eagle Rock Blvd. to Mission Rd., and the Eagle
Rock Area Relief Sewer Phases 2B, 2C, and 2D. Additionally, the
City was required to reduce the risk of SSOs by bypassing filtration
processes at the Tillman and LA/Glendale Plants under specified
conditions until completion of the ECIS and NEIS projects.
K-69
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
CA City of Pacifica, Calera
Creek Water Recycling
Plant
CA Coachella Valley Water 2001
District, Colorado River
Basin Region
CA Fort Bragg Municipal 03/22/01
Improvement District No.
1.WWTF
CA Fort Bragg Municipal 03/28/02
Improvement District No.
1.WWTF
CA Long Beach Water 07/11/02
Reclamation Plant, Long
Beach
Description
This Order required the City to either pay a civil liability in the
amount of $125,033 or, pay a $10,000 and complete a SEP in the
amount of $115,033.
This Order addressed the discharge of untreated wastewater to the
Coachella Branch of the All American Canal and Lake Cahuilla.
This was a Cease and Desist Order which modified the time
schedule of a previous Order to reflect a nine month delay in the
NPDES permit renewal.
This Order addressed their request to adjust the 2001 time
schedule to reflect delay in permit renewal, with the exception of
those tasks already completed.
The Order required them to complete construction of the modified
process for nitrification and de-nitrification, submit a pollution
prevention plan (PPP) workplan with a time schedule for
implementation of the construction, achieve compliance with its
permit, and submit quarterly progress reports.
CA Los Coyotes Water
Reclamation Plant,
Cerritos
07/11/02 The Order required them to complete construction of the modified
process for nitrification and de-nitrification, submit a PPP workplan
with a time schedule for implementation of the construction, achieve
compliance with its permit, and submit quarterly progress reports.
CA Orange County Sanitation
District (OCSD), Fountain
Valley
CA Orange County Sanitation 10/12/00
District (OCSD), Fountain
Valley
This Order addressed the release and spill of approximately
122,000 gallons of sewage. An estimated 20,000 gallons was
recovered and an estimated 102,000 gallons entered Newport Bay.
As a result of this spill a precautionary beach closure for all
beaches within the western half of Newport Bay was issued for six
days.
This Order addressed an estimated 60,600 gallons of sewage
overflowing from a manhole in Beach Blvd., approximately 200 feet
south of Imperial Highway. As a result, sewage flowed
approximately 1,000 feet to a storm drain drop inlet and eventually
entered Coyote Creek. An estimated 1,000 gallons of sewage was
recovered, and approximately 59,600 gallons were not recovered.
CA Sonoma County 05/23/01
Sanitation District, City of
Sonoma
Two Administrative Orders were issued addressing violations of its
NPDES permit limits during two separate periods. Action was taken
to address their pollution prevention/ source reduction and
pretreatment programs not being managed adequately or
implemented aggressively enough.
CA Sonoma County 04/01/02
Sanitation District, City of
Sonoma
This Order required them to cease and desist from discharging
wastes in violation of its NPDES permit and, they were required to
continue and expand its current "Zinc Source Identification and
Reduction Study." The Order also indicated that if they were
successful in identifying the sources of zinc in its effluent, then a
workplan identifying all necessary courses of actions to reduce the
zinc in its treatment plant influent and effluent.
K-70
-------
Appendix K
Region State Case Name/City Name Effective Date
CA Whittier Narrows Water 08/29/02
Reclamation Plant, El
Monte
CA Yucaipa Valley Water 01/24/03
District, Yucaipa
10
OR City of Albany
05/16/01
Description
The Order required them to complete construction of the modified
process for nitrification and de-nitrification, submit a PPP workplan
with a time schedule for implementation of the construction, achieve
compliance with its permit, and submit quarterly progress reports.
This Order addressed 28 effluent limit violations and a penalty of
$84,000 was assessed. They agreed to perform a SEP that would
benefit the Upper Santa Ana Watershed, contributing $49,500
towards the cleanup of the perchlorate contamination in the Colton-
Rialto area.
The City was required to complete constructin and attain
operational level of the Maple Street pump station and force main
upgrades by 10/31/02, and complete construction and attain
operational level of the approved treatment facility improvements by
12/31/09. A$107,5000 civil liability was imposed.
10
OR City of Amity
03/01/00 Under this Order, the City was required to submit construction plans
and specifications for upgrading the drinking water system and
complete the necessary upgrades or improvements within 22
months of this Order. They were also required to submit a
Reclaimed Water Use Plan outlining the minimum rule
requirements for how the City will achieve compliance and a final
Phase I and Phase II construction plans and specifications for
completing improvements to the WWTP.
10 OR City of Amity
10 OR City of Amity
10 OR City of Amity
Amendment This amendment to the March 2000 Order approved the City's
04/12/00 request for an extension to one compliance date requiring the City
to submit a Reclaimed Water Use Planby 10/01/00.
Amendment This amendment to the March 2000 Order approved the City's
11/02/00 request for an extension to one compliance date requiring the City
to submit a Reclaimed Water Use Planby 02/01/01.
Amendment This amendment required them to, among other things, complete all
03/28/02 necessary upgrades to the drinking water system by 09/01/02.
Additionally, by 05/20/02, they were required to submit engineering
plans and specifications for the entire wastewater improvement
project and by 10/01/03, complete the upgrades to the wastewater
treatment facilities.
10
10
10
OR City of Amity
OR
OR
City of Ashland
City of Brookings
Amendment This amendment approved the request for an extension to the
05/17/02 engineering plans and specifications from 05/20/02 to 07/30/02.
02/06/95 This Order required the City to submit to the Department for
approval a complete facilities plan by 10/95.
04/16/92 Under this Order, the City was required to complete construction on
the facultative sludge lagoon(s) and associated structures by
11/01/93, and complete construction on the Wastewater Treatment
Plant Improvement Project by 12/01/94.
K-71
-------
Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
10 OR City of Coos Bay, WWTF 08/21/03
#1
Description
This Order addressed the prevention of future waste discharge
violations. The Order required that within 12 months of approval of
the final engineering Plans and Specifications, the City will
complete construction of the wastewater control facilities.
10 OR City of Coos Bay, WWTF 08/21/03
#2
10 OR City of Falls City, OR 04/04/00
This Order required that within two years after award of a contract
for construction, the City will complete construction of the approved
wastewater control facilities and initiate operations.
This Order required that within six months following the
Department's approval of the Final Plans and Specifications, the
City will complete the removal of the Fair Oaks Pump Station and
replace it with a gravity line. They were also required to complete
the necessary optimization/upgrades to the WWTF.
10 OR City of Garibaldi
10/01/02 The Order required the City to complete the upgrades/expansion to
the WWTFs as specified in the approved engineering Plans and
Specifications and comply with all permit requirements, State, and
Federal regulations and water quality standards by 05/31/04.
10 OR City of Glendale
11/03/98 This Order required the City to complete the necessary upgrades or
improvements to the drinking water system and achieve compliance
with all applicable drinking water requirements by 09/30/01,
complete the removal of inflow sources identified and prioritized in
the Inflow Evaluation and Reduction Report for the WWTFs by
10/01/00, and complete the necessary upgrades/expansion to the
WWTFs and comply with all permit requirements, State, and
Federal regulations and water quality standards by 12/31/03.
10 OR City of Grants Pass 10/24/01
10 OR City of Lowell, OR 11/08/01
10 OR City of McMinnville 04/05/93
10 OR City of Medford
12/27/02
The Order required that within two years of Department approval of
diffuser Plans and Specifications, the City will complete
construction of the effluent diffuser.
This Order required that within 18 months after award of the
construction contract, the City will complete construction
upgrades/expansions required by the approved engineering Plans
and Specifications.
The Order required the City to upgrade and repair its sewage
collection system pursuant to the approved overall I/I Correction
Plan by 10/31/99.
This Order required the City to complete construction of Phase I of
the City's Best Management Practices (BMPs) by 06/02/03, and
complete construction of Phase II of the City's BMPs by 03/01/04.
10 OR City of Monroe
11/03/98 This Order required the City to complete the necessary upgrades or
improvements to the drinking water system by 01/02/01, install and
operate an influent flow meter at the treatment plant site by
10/31/98, complete the removal of all inflow sources identified in
the approved Pre-Design Report by 11/01/03, and complete the
necessary upgrades/expansion to the WWTFs by 11/01/06.
K-72
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Appendix K
Region State Case Name/City Name Effective Date
10 OR City of Myrtle Creek 05/30/02
10 OR City of Powers 12/29/00
Description
This Order required the City to have wastewater control facilities in
operation to comply with water quality standards immediately upon
approval of Plans and Specifications and have the WWTF will be
constructed and operational by 12/31/04.
This Order required the City to complete Phase I by 10/01/03, and
no later than the same time as completion of Phase I, the City will
complete monitoring of flows in the collection lines, complete Phase
II by 10/01/02, and complete all upgrades to the WWTP and
comply with all NPDES permit conditions by 10/01/05.
10 OR City of Rainier
12/15/95 The City was required to complete the upgrades to the drinking
water treatment facility within 15 months following approval of the
Plans and Specifications. Additionally, they were required to
complete Phase I of the interim improvements to the WWTF by
01/02/96, complete Phase II of the interim improvements to the
WWTF by 01/02/97, and complete the decommissioning of the
underground storage tanks (USTs) within four months of approval
of the decommissioning plan.
10 OR City of Salem
10 OR City of Sweet Home
10 OR City of Sweet Home
10 OR City of Sweet Home
10 OR City of Tillamook
01/21/98 This Order required the City to complete construction and initiated
operation of the approved facilities and complete construction for all
projects identified in the Salem Master Plan for the purposes of
eliminating overflows to tributary streams by 01/01/00, and
eliminate all SSOs by 12/31/09.
01/19/99 This Order required the City to complete the removal of all
reasonably removable inflow sources into the City's wastewater
collection system by 01/15/00. Within two years after award of
construction contracts, the City will complete construction of the
wastewater improvements.
Modification This Order required the City to submit a draft facility plan and time
1 /19/01 schedule that evaluates alternatives for either increasing treatment
capacity or reducing raw sewage flows down to the current
treatment capacity by 10/31/05.
05/09/01 This was a modification approving the City's request to extend the
compliance deadlines.
01/06/03 This Order required the City to complete construction of a new
digester supernatant pump station and modifications and repairs for
the RBCs as required in the approved Plans and Specifications for
the expanded Corrective Action Plan by 05/01/03. Additionally, the
City was required to complete construction of the modifications to
the facilities and repairs to the wastewater treatment facilities as
required by the approved plans and specifications for the expanded
Corrective Action Plan by 07/31/03.
10 OR City of Toledo 11/15/00
10 OR City of Warrenton 12/24/01
This Order required that within 24 months after award of the
construction contract, the City will complete construction of the
necessary improvements.
This Order required that within 15 months of awarding contracts for
construction, the construction of the approved Plans and
Specifications will be complete.
K-73
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name Effective Date
10
OR City of Willamina
09/26/96
Description
This Order required that within 12 months following the award of the
construction contract, the City will complete construction of the
necessary Phase I and Phase II improvements. By 07/01/03, the
City will complete inflow corrective work.
10 OR Clackamas County 01/13/94
Service District #1,
Oregon City
10 OR Oak Lodge Sanitary 05/17/95
District, Clackamas
County
10 OR Roseburg Urban Sanitary 06/27/94
Authority, Douglas County
10 OR Roseburg Urban Sanitary 09/30/92
Authority, Douglas County
The Order required the County to have their wastewater control
facilities in compliance with the water quality standards for chlorine
by 12/31/94.
This Order required the District to have wastewater control facilities
in operation to comply with the water quality standards for chlorine
by 12/31/98.
This Order required the Authority to complete construction and
installation of the back-up power generators at the Goedeck Waste
Water Treatment Plant by 02/15/95.
This Order required that within eighteen months after approval of
the engineering Plans and Specifications, the City will complete
construction of the necessary improvements.
10 OR Tri-City Service District, 02/28/94
Clackamas
This Order required the District to complete the planning, designing,
financing, and construction to increase the pump station capacity to
accommodate a one in five year event and thereby substantially
relieve bypass/overflows from certain discharge points by 07/01/97.
FL
FL
City of St. Petersburg 02/04/00
The Order required the City to budget appropriate monies,
implement, and complete the recommendations for improvements
to the Facilities and Systems established in the Final Report. They
were also required to immediately initiate the capital improvements
set forth in the Order, which were expected to be complete within
seven years. In lieu of a $391,533 civil penalty, they elected to
implement several in-kind penalty projects.
K-74
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Appendix K
K.11 State CSO Administrative Penalty Orders
Region State Case Name/City Name
1 ME City of Bath
1 ME City of Biddeford
1 ME City of Brewer
1 ME Town of Lisbon
2 NJ Camden County Municipal Utilities Authority
2 NJ City of Camden
2 NJ City of Gloucester
2 NJ City of Newark
2 NJ City of Paterson
2 NJ City of Rahway
2 NJ Middlesex County Utilities Authority
2 NJ Middlesex County Utilities Authority (MCUA)
4 TN Metropolitan Government of Nashville and
Davidson County
5 IN Bluffton POTW
5 IN City of Sullivan
5 IN Town of Remington
5 IN Town of Ridgeville
5 IN Town of Sullivan
Effective Date Penalty Amount
01/09/92
07/22/91
02/27/92
05/24/90
07/11/98
08/23/99
07/22/99
05/09/01
02/01/99
05/08/00
04/13/95
06/05/96
09/17/99
06/06/03
01/22/03
06/06/03
10/15/01
01/22/03
$14,000
$24,000
$75,000
$10,400
$1,886
$17,680
$9,875
$30,709
$15,000
$8,953
$336,750
$54,000
$600,000
$60,000
$575
$825
$750
$2,625
K-75
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Report to Congress on the Impacts and Control of CSOs and SSOs
K-76
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Appendix K
K.I 2 State SSO Administrative Penalty Orders
• Region
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
State
AL
AL
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
Case Name/City Name
Demopolis Waterworks and Sewer Board, City of
Demopolis
Stevenson Utilities Board, Stevenson Wastewater
Treatment Lagoon, Stevenson
Belmont City-A Sludge/Lars
Mebane Bridge WWTP
Morrisville Town-Carpenter Plant
Murfreesboro Town-WWTP
Neuse Crossing WWTP
Pond Creek WWTP
Sanford WWTP
Sanford WWTP
Town of Canton
Town of Green Level
Warsaw WWTP
Wrenn Road Spray Irrigation Facility
City of Alexandria
City of Bluff City
City of Church Hill
City of East Ridge
City of Franklin
City of Franklin
City of Greenbrier
City of Harriman
City of Harriman
City of Jellico
City of Kingston
City of Lafayette
City of LaVergne
City of LaVergne
City of Lawrenceburg
City of Middleton
City of Murfreesboro
City of Murfreesboro
Effective Date
08/02/01
01/09/02
10/30/01
01/25/02
04/11/00
10/11/00
02/17/00
01/25/02
11/25/02
07/09/03
03/27/00
03/16/01
08/03/00
03/16/01
1 0/02/02
07/25/98
04/02/97
04/29/96
1 0/26/99
11/13/00
03/20/00
06/28/00
07/23/02
10/03/97
11/30/01
04/22/03
11/08/99
10/24/00
03/27/01
08/25/00
08/21/99
05/22/01
Penalty Amount
$5,300
$1,300
$4,234
$1,774
$7,421
$4,240
$10,801
$4,100
$18,214
$19,423
$21,742
$5,862
$12,517
$7,295
$104,000
$17,750
$5,000
$30,000
$6,326 - Damage Fee; $3,750
Civil Penalty
•
-
$78,295 - Damage Fee; $57,500
Civil Penalty
$141,750
$266,250
$30,000
$11,500
$207,000
$92,500
$2,500
$2,000
$9,375
$47,750
$400,000
In lieu of paying the $50,000
civil penalty, the City agreed
to perform a Supplemental
Environmental Project (SEP).
The City was supposed to
purchase a five-acre lot which
had a wetland.
4 TN City of Portland Public Works
4 TN City of Red Bank
4 TN City of Rockwood
4 TN City of Sparta
4 TN City of Watertown
4 TN City of Watertown
08/02/02 $541 - Damage Fee; $5,000 -
Penalty Fee
02/25/97 $164,500
10/29/98 $16,750
10/04/00 $62,000
02/08/00 $1,100
06/03/03 $87,500
K-77
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name
4
4
4
4
4
4
4
4
4
4
4
9
9
9
9
9
9
9
9
9
9
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
OK
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
Knoxville Utilities Board
Lynnwood Utility Corporation
Metropolitan Government of Nashville and
Davidson County
Effective Date Penalty Amount
05/20/03 $475,000
$5,000
09/17/99 Of the total $600,000 penalty,
$100,000 was due within one
month of this Order. However,
in lieu of the $100,000, they
agreed to perform a SEP.
$118,500
$67,625
$5,500
$115,500
$3,000
$58,250
$15,000
$73,312
$5,000
$96,000
$33,000
$135,000
$87,000
Town of Collierville 06/03/98
Town of Gainesboro 11/22/00
Town of Gainesboro 03/27/01
Town of Monterey 09/11702
Town of Mosheim 04/25/01
Town of Pikeville 01/09/00
Town of Spring City 07/31/03
Town of Spring Hill 01/26/00
CityofHoldenville 11/07/02
California Department of Corrections, Sierra 06/01/01
Conservation Center WTF, Tuolumne County
California Department of Parks and
Recreation, Angel Island State Park
California Department of Parks and 09/20/02
Recreation, Big Basin Redwoods State Park
WWTP
California Men's Colony San Luis Obispo 10/26/01
County and Indirect Dischargers and Local
Sewering Entities of Camp San Luis Obispo,
Cuesta College, San Louis Obispo County
Educational Center, and San Luis Obispo
County Operational Facility
Carpinteria Sanitary District, Santa Barbara 04/09/01 $6,000
County
Cedars-Sinai Medical Center, Imaging 09/27/02 $3,000
Building
Centinela State Prison WWTF, Imperial 04/30/01 $33,000
County
Centinela State Prison WWTF, Imperial 2000 $9,000
County
Central Marin Sanitation Agency, San Rafael, $15,000
Marin County
Central Marin Sanitation District, San Rafael, 2001 $6,000
Marin County
Cities of South San Francisco and San Bruno 07/16/03 $81,000
Water Quality Control Plant
City and County of San Francisco, Southeast $3,000
Water Pollution Control Plant
K-78
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Appendix K
1 Region
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
State
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
Case Name/City Name
City of Anderson Water Pollution Control
Plant, Shasta County
City of Anderson Water Pollution Control
Plant, Shasta County
City of Anderson Water Pollution Control
Plant, Shasta County
City of Anderson Water Pollution Control
Plant, Shasta County
City of Atwater WWTF, Merced County
City of Atwater WWTF, Merced County
City of Benicia WWTP, Solano County
City of Benicia WWTP, Solano County
City of Benicia WWTP, Solano County
City of Brawley WWTF, Imperial County
City of Brawley WWTF, Imperial County
City of Brawley WWTF, Imperial County
City of Brentwood WWTP, Contra Costa
County
City of Burlingame, San Mateo County
City of Chico WWTF, Butte County
City of Chico WWTF, Butte County
City of Corona
City of Corona
City of Coronado, Glorietta Bay Pump Station
Construction Dewatering
City of El Centra WWTP
City of Escondido Hale Avenue Resource
Recovery Facility, San Diego County
City of Escondido, San Diego County
City of Lakewood, Department of Water
Resources
City of Livermore, Alameda County
City of Morro Bay and Cayucos Sanitary
District WWTP, San Luis Obispo County
City of Palo Alto, Santa Clara County
City of Pasadena Department of Water and
Power (Power Plant)
City of Petaluma, Sonoma County
City of Redondo Beach, Seaside Lagoon
City of Rialto
City of Rio Vista Trilogy WWTF, Solano
County
City of Rio Vista WWTF, Solano County
City of San Diego, San Diego Convention
Center Dewatering
City of San Mateo Wastewater Treatment
Plant, San Mateo County
City of Santa Cruz
City of Santa Rosa, Laguna Subregional
WWT, Reuse, and Disposal Facilities
Effective Date
2000
2000
04/27/01
2000
2000
10/29/2001
03/15/02
2001
2000
07/26/01
12/21/01
01/29/00
2000
2001
1 0/09/02
07/27/00
09/29/00
05/09/02
1 0/07/03
08/19/02
02/01/02
03/29/02
08/02/02
07/10/02
07/10/02
04/25/02
01/24/03
07/30/02
04/30/02
Penalty Amount ^^1
$3,000
$10,000
$3,000
$10,000
$36,000
$30,000
$3,000
$9,000
$18,000
$33,000
$6,000
$3,000
$243,000
$3,000
$6,000
$100,000
$15,000
$288,000
$39,000
$15,000
$3,000
$6,000
$3,000
$15,000
$12,000
$12,000
$6,000
$30,000
$51,000
$30,000
$3,000
$6,000
$81,000
$39,000
$40,000
$15,000
K-79
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Report to Congress on Impacts and Control ofCSOs and SSOs
Region State Case Name/City Name
Effective Date Penalty Amount
9
9
9
9
9
9
9
9
9
9
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
07/10/02
04/30/01
04/30/01
2001
03/15/02
$27,000
$45,000
$27,000
$3,000
$51,000
$24,000
9 CA City of Santa Rosa, Subregional Wastewater 05/02/02 $12,350
Treatment, Reuse and Disposal Facilities
9 CA City of Vacaville WWTP, Solano County
9 CA Coachella Sanitary District WWTF Coachella,
^^^^^^^^^ Riverside County
9 CA Coachella Sanitary District WWTF, Riverside
County
9 CA Coachella Sanitary District WWTF, Riverside
County
9 CA Coachella Sanitary District WWTF, Riverside
County
9 CA Coachella Sanitary District, Owner/Operator
Coachella Sanitary District WWTF Coachella,
Riverside County
9 CA Coachella Valley Water District WWTP $20,000
9 CA Colton/San Bernardino Regional Tertiary 08/02/02 $54,000
Treatment and Water Reclamation Authority
9 CA County of Los Angeles Department of Parks 09/23/02 $21,000
and Recreation, Val Verde County Park
Swimming Pool
9 CA County of Los Angeles Department of Public 09/27/02 $24,000
Works Alamitos Barrier Project (San Gabriel
River), Long Beach
County of Los Angeles Department of Public 12/05/02 $6,000
Works Storm Drain Project 9037
Department of Public Works City of Los 09/27/02 $51,000
Angeles, Marina Interceptor Sewer
East Bay Municipal Utility District, Orinda $9,000
WTP, Contra Costa County
East Bay Municipal Utility District, Orinda $25,000
WTP, Contra Costa County
Eastern Municipal Water District 06/22/00 $10,000
Fairfield Suisun Sanitary District, Solano $9,000
County
Fallbrook Public Utility District 12/11/02 $87,000
Fallbrook Public Utility District WWTP No.1, 10/24/02 $87,000
San Diego
Harris Water Conditioning, Inc., Culligan Soft 02/07/02 $9,000
Water
Las Virgenes Municipal Water District, Tapia 03/27/02 $12,000
Water Reclamation Plant, Calabasas
9 CA Mt. View Sanitary District, Contra Costa $3,000
County
9 CA Napa Sanitation District, Napa County $153,000
9 CA Natural History Museum of Los Angeles 08/19/02 $3,000
County
K-80
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Appendix K
Region State Case Name/City Name
Effective Date Penalty Amount
9 CA Rancho California Water District, Santa Rosa 03/13/02 $66,000
Water Reclamation Facility, Riverside County
Rancho California Water District, Well No. 12/11/02 $3,000
121
Rodeo Sanitary District, Contra Costa County $33,000
San Francisco International Airport, Water $27,000
Quality Control Plant
Sewerage Agency of Southern Martin, Mill $6,000
Valley, Marin County
Southern California Water Company, Yukon 01/11/02 $21,000
Plant
State of California Department of Corrections, $6,000
Centinela State Prison WWTF, Imperial
County
9 CA The City of Chico WWTF, Butte County $9,000
9 CA The City of Santa Cruz 09/20/02 $40,000
9 CA University of California at Los Angeles 03/06/01 $6,000
9 CA West County Wastewater District, Contra $192,000
^^^^^^^ Costa County
9 CA Western Riverside County Regional 01/18/02 $96,000
Wastewater Authority
9 CA Yucaipa Valley Water District $39,000
9 CA Yucaipa Valley Water District $48,000
10 OR City of Albany 05/16/01 $5,080
9
9
9
9
9
9
CA
CA
CA
CA
CA
CA
K-81
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Appendix L
Technology Descriptions
L.I Operation and Maintenance
Practices
Sewer Testing and Inspection
Techniques
Sewer Cleaning Techniques
Pollution Prevention
Monitoring, Reporting, and
Public Notification
L.2 Collection System Controls
Maximizing Flow to Treatment
Plant
Monitoring & Real-Time Control
Inflow Reduction
Sewer Separation
Sewer Rehabilitation
Service Lateral Rehabilitation
Manhole Rehabilitation
L.3 Storage Facilities
In-line Storage
Off-line Storage
On-site Storage
L.4 Treatment Technologies
Supplemental Treatment
Plant Modifications
Disinfection
Vortex Separators
Floatables Control
L.5 Low-Impact Development
Techniques
Porous Pavement
Green Roofs
Bioretention
Water Conservation
-------
-------
RIPTION
OPERATIC^
Sewer Testing and
Inspection Techniques
Overview
Operations and maintenance practices, such as sewer
testing and inspection, enhance sewer system performance.
Specifically, testing and inspection practices ensure that
new connections are made correctly, help locate and protect
against unwanted inflow and infiltration (I/I), and assess
the structural condition of the sewer system. Inspection
techniques can also be useful in identifying locations
where grease and debris accumulate or where roots intrude
into the sewer, which can cause sewer blockages resulting
in unexpected CSOs and SSOs. The keys to a successful
sewer testing and inspection program are identification
of potential or current problem locations; correction of
the problem; and evaluation of the effectiveness of the
corrective measures.
Sewer Testing Techniques
In general, sewer testing techniques are used to identify
leaks which allow unwanted infilitration into the sewer
system and determine the location of illicit connections
and other sources of storm water inflow. Air testing and
hydrostatic testing are used to identify leaks in the sewer
system. Smoke testing is used to determine connectivity
and to identify points where inflow to the sewer system can
occur. These testing techniques are described in further
detail below.
Air Testing
Air testing is used to determine if a particular section
of sewer line has leaks that would allow unwanted
groundwater to infiltrate into the system or sewage
to exfiltrate into the surrounding soil. Plugs, such
as inflatable stoppers, are placed at either end of the
test section, and in all service connections to the
section. The test section is pressurized with air. After
the pressure is allowed to stabilize, it is monitored
for a predetermined amount of time. The acceptable
range of pressure drop and the duration of the test are
based on the pipe material and diameter, detailed in
American Society for Testing and Materials (ASTM)
standards. An unacceptable drop in the pressure
indicates that the pipe has leaks that could lead to
excessive infiltration. To isolate the leaks, air testing can
be repeated on smaller sections of line.
Hydrostatic Testing
Hydrostatic testing is another technique used to detect
and locate leaks in a sewer system. As with air testing,
the sewer reach of interest is isolated using plugs. The
test section is filled with standing water and the water
level is monitored. A drop in the water level over time
indicates the presence of leaks. The acceptable decrease
in water level and the test duration are specified in
ASTM standards based on pipe material.
Smoke Testing
Smoke testing is commonly used to detect sources of
unwanted inflow such as down spouts, or driveway
and yard drains. With each end of the sewer of interest
plugged, smoke is introduced into the test section,
usually via a manhole. Sources of inflow can then be
identified when smoke escapes through them. This
technique can also be used to identify cross connections
between sanitary and storm sewer systems. The smoke
can be tracked through the sewer system for a limited
distance. The length of the sewer that can be tested at
one time is dependent on a number of environmental
factors affecting smoke dissipation, such as wind and
the number of sewer and surface connections to the
system.
Sewer Inspection Techniques
Sewer inspection is an important component of any
maintenance program. Sewer inspections establish the
current condition of sewer lines and identify potential
problems. The most common sewer system inspection
techniques are described in detail below.
Visual Inspection
Visual inspection, which is the most basic sewer
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Report to Congress on the Impacts and Control ofCSOs and SSOs
inspection technique, can include surface and internal
inspections. In either case, the manhole cover is
removed and an inspection of the manhole condition,
as well as the flow characteristics in the pipe, is made.
For smaller pipes, mirrors and lights can be used
to inspect the first few feet of pipe upstream and
downstream of each accessible manhole. For larger
pipes, a maintenance crew member can enter the pipe
to inspect the inside of the pipe.
Lamping
Lamping involves lowering a still camera into a
maintenance shaft or manhole. The camera is lined
up with the center line of the junction of the manhole
frame and the sewer. A picture is then taken down the
pipe using a strobe-like flash. This method can typically
be used to inspect the first 10-12 feet of the pipe
upstream and downstream from the access point.
Camera Inspection
Camera inspection is slightly more comprehensive
than lamping. In camera inspections, a still camera is
mounted on a floatable raft that is released into a pipe.
As it floats down in the sewer, the camera takes pictures
of the pipe using a strobe-like flash. Camera inspections
can be performed in any pipe that is large enough to
accommodate the camera and raft device.
Closed-Circuit Television
Closed-circuit television (CCTV) is the most
commonly used technique for inspecting the internal
condition of a sewer (EPA 1999). A closed-circuit
camera with a light is self-propelled or pulled down the
pipe. As it moves, it records the interior of the pipe. The
focus of the camera can be controlled remotely for a
clear image of points of interest. The distance traveled
is recorded so that the location of any irregularities
can be noted. This technique can be used in lines with
a diameter ranging from 4-inches to 48-inches (CSU
2001).
Sonar
Sonar is a newer technology available for inspecting
sewer lines. Sonar is deployed in the same manner as
CCTV cameras and, therefore, can be used in the same
diameter pipes. Sonar works by emitting a pulse that
is bounced off the walls of the sewer. The time it takes
for the pulse to bounce back is a function of the wall
geometry. This wall geometry can then be analyzed to
develop an image of the interior of the pipe. At low
frequencies, less than 200 kHz, the pulse can penetrate
the walls and provide information on the structural
condition of the pipe.
Sewer Scanner and Evaluation Technology
Sewer Scanner and Evaluation Technology (SSET) is an
experimental sewer line inspection technology. A full digital
picture of the interior of a pipe can be produced by using a
probe with a 360 degree scanner.
Key Considerations
Sewer Testing Techniques
The location and elimination of leaks in a sewer system
are the major concern of system operators (CSU 2001). An
effective sewer testing and inspection program will identify
existing leaks and prevent other leaks from developing. Key
considerations, including advantages and disadvantages, in
selecting appropriate testing and inspection techniques are
detailed below.
Air Testing
Air testing tests the entire circumference of the pipe
for leaks by exerting the same amount of pressure in all
directions on the pipe. Air can leak through a smaller
crack than wastewater, therefore air testing helps find
vapor leaks which may attract roots. In addition, in
areas with steep terrain, air tests are better than water
tests because of excessive hydrostatic pressure created at
the lower end of the sewer line (CSU 2001). However,
air testing can be difficult to apply in areas that have
numerous service lateral connections as each one must
be individually plugged, and the test section must be
taken out of service during air testing. Due to safety
concerns, air testing can also only be used in 4-inch to
24-inch pipes. For example, pressure on a 24-inch plug,
even during a low pressure test, is enough to cause an
improperly installed plug to explode (Rinker Material
2002).
Hydrostatic Testing
Hydrostatic testing also requires that the test section be
taken out of service during testing. Individual service
lateral connections do not need to be plugged as long
as the water level at which the test is conducted is below
that of the lowest basement in the test area. However, if
residential taps are not plugged, the service laterals will
be included in the test area. Further, since the release of
pressure due to a failure of a plug in the hydrostatic test
is much lower than in an air test, it can be conducted
in larger diameter pipes. The principle disadvantages
of hydrostatic testing are the time, money, and water
wasted in conducting these tests (CSU 2001).
Smoke Testing
Smoke testing does not require the test section to be
removed from service. However, all floor and sink
drains must be filled with water prior to introducing
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Operation & Maintenance: Sewer Testing and Inspection Techniques
smoke to the system. Use of smoke testing is best done
when the groundwater levels are low (i.e., below the
elevation of the pipe) so that any cracks will leak smoke.
It is important to realize that the location of smoke on
the ground surface does not necessarily reveal where the
smoke is escaping underground, but rather the point of
exit at the ground surface (CSU 2001).
Sewer Inspection Techniques
Logging and recording inspections is critical to ensuring
their utility. Typically, each municipality will have a standard
log sheet for recording observations made through any of
the inspection techniques described below. In cases where
old sewers are to be inspected, it may be important to clean
the lines before inspection. Ideally, sewer line inspections will
take place during low flow conditions. Key considerations for
different inspection techniques are discussed below.
Visual Inspections
In conducting visual inspections of sewer interiors, the
maintenance crew is required by law to have confined
space entry training and to strictly follow confined
space entry procedures. Safety concerns also arise when
attempting visual inspections in sewers with access
points more than 600 feet apart.
Lamping
Lamping does not require confined space entry.
Additionally, little equipment and set-up time are
needed. Inspection is only possible, however, in the areas
clearly captured in the photograph. Further, lamping has
limited use in small diameter sewers (CSU 2001).
Camera Inspection
Camera inspection is often a viable alterative to visual
inspections in larger sewers when the access points
are more than 900 feet apart. The main disadvantage
of camera inspection, similar to lamping, is that the
pictures are not comprehensive and portions of the
pipe may be missed. Additionally, there must be flow in
the pipe for the raft to float. If there is flow in the pipe
usually the invert of the pipe cannot be seen and is not
photographed. Therefore, this method of inspection
does not fully capture the condition of the invert of the
Pipe-
Closed-Circuit Television
One of the primary advantages of CCTV over still-
photography methods, such as lamping and camera
inspections, is that the camera can be stopped and
pulled back or forth for a more precise observation.
A footage meter can also be used in conjunction with
CCTV equipment to keep track of the location of any
irregularities. CCTV, however, cannot capture pipe
condition below the water. In addition, CCTV-based
assessment is subjective and can be error prone as its
accuracy depends heavily on the skill and concentration
of the operator.
Sonar Technology
Sonar technology is able to map the sewer condition
both above and below the level of flow. The primary
use for sonar equipment is to inspect and assess the
structural condition of otherwise inaccessible or flooded
sections of sewer lines. The disadvantage is that it
requires more power and heavy equipment than the
CCTV, and therefore tends to be more expensive.
Sewer Scanner and Evaluation Technology
Similar to sonar, SSET also offers the benefits of a
more complete image of the pipe than CCTV, but this
technology is still in the experimental phase. SSET
does not identify all types of sewer defects, such as
infiltration and corrosion, equally. Also, it is not possible
to see laterals, and SSET is slow compared to CCTV
(CERE 2000). It appears that comprehensive data on
the condition of the pipeline can be determined by
combining SSET with CCTV.
Cost
Costs for testing and inspection will vary based on
location and technique used. CCTV is the most commonly
used inspection technique and the costs are presented in
Table 1.
Table 1. CCTV costs per linear foot, includes labor
and equipment costs.
Location
Los Angeles, CA
Sacramento, CA
Santa Rosa,CA
Honolulu,HI
Boston, MA
Laurel, MD
Albuquerque, NM
Charleston, SC
FortWorthJX
Fairfax County, VA
Norfolk, VA
Virginia Beach,VA
Average
1 Costs in 2002 dollars.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Implementation Examples
FORT WORTH, TX
Sewer Maintenance and Service Program
Responsible Agency: City of Fort Worth
Population Served-880 000 ~^e ^'^ °f Fort Worth Water Department created a Preventative Maintenance
Section and a Technical Service Section in 1998.The Preventive Maintenance
Service Area: 291 sq. mi. r ,.. . , .,, . . ,.. ., .... ,.
Section was tasked with implementing a system-wide small diameter (less
n: 2,589 mi. of sewer than , 8 jnches) sewer deaning and inspection program. Larger pipes are
cleaned and inspected by private contractors, due to technical logistics and
the specialized equipment needed.The Sewer Maintenance Section handles
all other sewer maintenance activities such as cleaning blockages,and pipe installation and repair.The sewer system is divided
into nine major drainage basins containing 167 subbasins. Each subbasin,along with its SSO and maintenance histories,is tracked
in a Geographic Information System (CIS) database. Spatial analysis based on information from the CIS database and baseline
performance criteria is used to prioritize the cleaning and inspection of the subbasins. Once a subbasin is selected for cleaning,
approximately two-thirds of the cleaned lines are evaluated by CCTV.This information is used as part of the decision making
process for determining whether or not further maintenance is needed. During 2001-2002,176 miles of pipe were televised.The
cost for inspection of small diameter sewers by city employees was $0.48 per linear foot including labor and equipment.
Contact: Darrell Gadberry, City of Fort Worth Water Department, Field Operations Division
FAIRFAX COUNTY, VA
Improved Sewer Maintenance Program
Responsible Agency: Fairfax County
Population Served: 835,000
Service Area: 234 sq. mi.
Sewer System: 3,100 mi. of sewer
Fairfax County believes that improved record keeping,along with
the reorganization and streamlining of their sewer maintenance
program, has resulted in significant reductions in SSOs in recent
years. By tracking the number of inspections and cleanings,as well
as the number of overflows in each individual line, the county has
established and prioritized inspection and cleaning schedules for
each line.This customized cleaning and inspection schedule,along with the resulting decrease in SSOs, led to a decrease in overall
sewer maintenance costs. Inspection activities include visual inspection using a mirror attached to a pole,a portable camera, and
CCTV.The sewers are then cleaned based on the regular schedule or sooner,as determined by the inspection results. In 2002,the
cost of visual inspection and cleaning was $0.87 per linear foot.The cost of CCTV inspection was $0.78 per linear foot.
Contact: Ifty Khan, Fairfax County Department of Public Works & Environmental Services,
Wastewater Collection Division
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Operation & Maintenance: Sewer Testing and Inspection Techniques
References
California State University (CSU), Sacramento, College
of Engineering and Computer Science, Office of Water
Programs. 2001. Operation and Maintenance of Waste-water
Collection Systems. Vol. 1, 5th ed. Prepared for EPA Office
of Water Programs, Municipal Permits and Operations
Division. Sacramento, CA: CSU, Sacramento Foundation.
Civil Engineering Research Foundation (CERF). 2000.
Sewer Scanner & Evaluation Technology (SSET). Retrieved
July 28, 2003.
http://www.cerf.org/ceitec/eval/ongoing/sset.htm
EPA Office of Water. 1999. Collection System Oe^M Fact
Sheet: Sewer Cleaning and Inspection. EPA 832-F-99-031.
Rinker Materials. 2002. Information Series: Low Pressure Air
Testing. Retrieved July 28, 2003.
http ://www.rinker.com/hydroconduit/infobriefs/i 105 .htm
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
0&M-5
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RIPTION
OPERATIC^
Sewer Cleaning
Techniques
Overview
Operations and maintenance practices, such as sewer
cleaning, enhance sewer system performance. Specifically,
sewer cleaning can remove blockages caused by the
deposition of solids and grease, as well as root intrusion.
Sewer cleaning is important in maintaining sewer system
capacity and can reduce the frequency and volume of CSOs
and SSOs.
The three major techniques used to clean wastewater sewer
systems are hydraulic, mechanical, and chemical. Some
of the more widely used technologies in each of these
categories are described below.
Hydraulic Cleaning Techniques
Jetting
Jetting involves aiming a high-pressure stream of water
at the blockage or debris in the pipe. The shape of the
nozzle can be changed depending on the surface in
need of cleaning (CSU 2001). Jet cleaners can either be
truck- or trailer-mounted. Jet cleaners are very efficient,
require minimal staff, and are able to handle most types
of sewers and blockages. Jetting is the most common
hydraulic cleaning technique due to its comparatively
low cost and effective cleaning results.
Balling
Balling involves inserting a rubber ball with a diameter
slightly smaller than the interior diameter of the pipe
into a sewer line. The ball is placed in the upstream end
of the sewer line and reduces the area through which
wastewater can pass, causing it to flow at a higher
velocity. This increased velocity flow scours the interior
of the pipe. Additional cleaning can also be achieved by
threading the ball so that it spins as water flows past,
scrubbing the interior of the pipe.
Kites
Kites are cone shaped devices that resemble a windsock
and are used to hydraulically clean sewers. Kites work
similar to balling, increasing the velocity of the flow so
that it scours the sewer line. They are made of a canvas
material that traps and funnels the wastewater so that
it is released as a high velocity stream. This wastewater
stream works to break up deposits in the line.
Scooters
Scooters consist of a metal shield attached to a wheeled
framework and are designed to be self-propelled. The
shields are available in various sizes for use in different
diameter pipes. Similar to the balling technique, the
scooter blocks the flow in the pipe and forces it to go
around the edges of the shield at a high velocity. The
wheeled framework allows the scooter to be pushed
by the wastewater built up behind it. The depth of
wastewater behind the scooter is controlled by a spring
system that adjusts the angle of the shield relative to
the walls of the pipe. By adjusting the angle of the
shield, the flow around the edges is either increased or
decreased. The high velocity water flowing around the
shield breaks up and moves debris down the pipe.
Flushing
There are two methods used in flushing sewers: manual
flushing and self-flushing. Manual flushing involves
introducing large volumes of low velocity water at the
upstream end of the sewer. The large flow volume
is capable of transporting floatables and low density,
loose debris to the downstream manhole for removal,
but not necessarily heavy or attached debris. This
method is most effective when used in combination
with a mechanical method such as rodding. Self-
flushing techniques use the flow within the sewer for
hydraulic cleaning. A gate or other device is used to
store a volume of wastewater and then release it in a
flood wave that washes deposits out of the sewer line.
Mechanical Cleaning Techniques
Rodding
Power rodding machines use an engine to force a
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Report to Congress on the Impacts and Control ofCSOs and SSOs
small diameter rod (less than one inch) through the
sewer line. The rod turns as it passes through the pipe.
Usually a cleaning attachment made of multiple small
blades is located at the end of the rod. The attachment
works to loosen and break up debris; it also cuts
through roots that protrude into the interior of the
pipe. In addition, power rodding can be used to thread
cables for closed-circuit television (CCTV) inspection
or bucket cleaning.
Bucket Machines
Bucket machines use a steel bucket that is pulled
through the sewer along a cable threaded between two
manholes. The front of the bucket has jaws that open
and scrape the debris and deposits from the interior
of the pipe capturing them in the bucket for removal.
Bucket machines are available in a range of sizes to
allow for cleaning of both small and large diameter
pipes. The power of the equipment being used to pull
the bucket determines the size of the pipe that can be
cleaned with this method.
Chemical Grouting Techniques
Herbicides
Roots can inhibit flow, collect debris, and reduce
the line's capacity. Herbicides are used to kill roots
protruding into the sewer line and inhibit future root
growth. Herbicides are typically applied by one of two
methods: soaking the roots inside the sewer with a
liquid solution for a short time period, or filling the
sewer with a herbicidal foam. Chemical root control
must be used in combination with some other cleaning
technique to remove the roots killed by the herbicides.
Enzyme Additives
Enzyme additives can be used to break up scum,
grease, and other accumulated organic matter. These
additives can control odors in the sewer system as well
as removing blockages. The additives usually come in a
dry flaky form and are applied in small doses.
Key Considerations
Selection of the most appropriate sewer cleaning technique
will need to be made on a site-specific basis. In general,
hydraulic cleaning techniques tend to be simpler and
more cost-effective in removing deposited solids when
compared to other sewer cleaning techniques (CSU
2001). Mechanical techniques are typically used in areas
where the volume, size, weight, or type of debris limit the
effectiveness of hydraulic techniques. Chemicals can be
helpful aids for cleaning and maintaining sewers, but most
chemical applications are localized or used to enhance
the effectiveness of other cleaning techniques. Specific
considerations for each of the aforementioned cleaning
techniques are described below.
Applicability
Hydraulic Cleaning Techniques
Jetting
Jetting is most effective in cleaning flat, slow-flowing,
smaller pipes (less than 15 inches in diameter). As the
pipe diameter increases, the distance between the high
velocity nozzle and the interior of the pipe increases,
which decreases its cleaning potential. Jetting is often
more effective in low flow pipes as the jets can easily
penetrate shallow flow to clean the deposits in the
invert of the pipe. Jetting must be used with caution
in pipes with fixtures such as gauges and valves as they
may be damaged by the jets. Basement backups can
occur if the jetting hose is mistakenly fed into a service
line, or if the volume of water introduced exceeds the
capacity of the sewer line.
Balling
Balling is best suited for removing deposits of inorganic
material and grease (CSU 2001). Balling can only be
used in areas where sufficient hydraulic capacity is
available to pressurize the water flowing around the
ball without causing sewer backups, and it is most
successful in 24-inch or smaller diameter pipes. It
cannot be used in sewer lines that have large offsets,
service connections, or roots protruding into the
sewer line since the ball can get caught. The required
frequency of balling varies from six months to three
years (CSU 2001).
Kites
Kites clean in a manner similar to balling, but they are
commonly used to clean larger diameter sewers. Kites
require only a small amount of hydraulic pressure to
create a cleansing velocity. Yet, they can only be used in
areas where sufficient hydraulic capacity is available to
pressurize the water flowing around the kite without
causing sewer backups. Some accommodation for
hydraulic capacity can be made by feeding the kite
through the system at a faster rate. However, this faster
rate may not allow for sufficient pressurization of the
water flowing out of the end of the kite. A kite cannot
be used in pipes with large offsets, which could cause
the kite to become lodged in the line.
Scooters
Scooters are capable of removing large objects and
heavy materials (i.e., brick, sand, gravel, and rocks).
Scooters are considered more effective in larger lines,
over 18 inches in diameter (CSU 2001). The operation
of a scooter is quite simple, and the cost is often
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Operation & Maintenance: Sewer Cleaning Techniques
considerably less than other cleaning operations. Since
scooters depend on the build-up of water pressure,
caution must be used where sewers are shallow or the
danger of flooding homes or businesses exists. A scooter
cannot be used in lines with protruding pipes or service
lateral connections, and it may not be appropriate for
lines with significant root intrusion, where it could
become entangled.
Flushing
Flushing is most often used in conjunction with other
mechanical techniques, especially rodding. Mechanical
devices are used to cut roots and grease from the walls
and joints of pipes. This is followed by flushing to
remove the cut material. Flushing is not as effective
as balling or jetting because sufficient velocities are
not developed to remove grease, grit, or heavy debris.
It is also important to note that the amount of water
required to clean a line is dependent on the size, length,
and slope of the line. Flushing is not a common practice
due to poor results and large volumes of water required
for cleaning, which ultimately flow to the wastewater
treatment plant.
Mechanical Cleaning Techniques
Rodding
Rodding is one of the most widely used methods for
cleaning sewers. Rodding is typically used to handle
stubborn stoppages of roots, grease, and debris (CSU
2001). This method works best when applied in pipes
with diameters of 12 inches or less. When used in larger
diameter pipes, the rod tends to bend and coil up on
itself. Rodding is most effective when it is applied in
conjunction with some form of flushing because it
works to loosen and break up debris, but rodding itself
does not remove debris from the line. If the rod happens
to break in the sewer line, retrieval and repair may be
very difficult.
Bucket Machines
Bucket machines are most often used to clean a line
after a pipe breaks or debris that cannot be removed
by hydraulic cleaning techniques accumulates. They
should not be used as a routine cleaning tool. Bucket
machines are heavy, and set-up of the equipment is more
time consuming than for other mechanical methods.
In addition, if the sewer line is completely blocked, the
pull cable cannot be threaded through the line, making
this method ineffective. Bucket machines are costly
to operate and maintain, and they can be potentially
damaging to sewer pipes.
Chemical Cleaning Techniques
Herbicides
Proper application of chemical root control is essential
in ensuring their effectiveness. Root control using
chemicals is not as fast as cutting roots with a power
rodder, however, it is more permanent. Effective
chemical application can control roots in a sewer for
two to five years (CSU 2001). It is important to take into
consideration how the toxicity of the herbicide will affect
the biological treatment process at the downstream
wastewater treatment plant.
Enzyme Additives
The addition of enzyme additives to control grease and
scum are effective under specified conditions in specific
locations. Careful comparison of the results produced
by the additives with those achieved via mechanical or
hydraulic cleaning methods should be made to ensure
that the most appropriate technique is selected.
Cost
Representative costs for various cleaning methods are
summarized in Table 1. The relative effectiveness of the
cleaning techniques is presented in Table 2.
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Table 1. Cleaning costs per linear foot.
Municipality
Los Angeles, CA
San Diego, CA
HammondJN
Afton,OH
Sioux Falls, SD
Fort Worth, TX
Fairfax,VA
Cleaning Method
Hydraulic- Jetting
Mechanical - Rodding
Mechanical - Manual Rodding
Overall Cleaning
Overall Cleaning
Overall Cleaning
Overall Cleaning
Overall Cleaning
Hydraulic- Jetting
Mechanical - Rodding
Average Cost per Linear
Foot1
$0.27
$0.41
$1.32
$0.54
$1.26
$0.42
$0.45
$0.61 -$1.02
$0.44
$0.86
1 Costs include labor and equipment.
Table 2. Effectiveness of sewer cleaning techniques (CSU 2001).
Cleaning Technique
Emergency
Stoppage
Maintenance Issue
(Effectiveness scaled from 1 =low to 5=high)
Sand, Grit,
Grease Roots _ . .
Debris
Jetting1
Balling
Kiting
Scooters
Flushing
Rodding
Bucket Machines
Chemicals
Microorganisms
Effectiveness decreases as pipe diameter increases.
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Operation & Maintenance: Sewer Cleaning Techniques
Implementation Examples
SIOUX FALLS, SD
Sewer Cleaning and Maintenance
Responsible Agency: City of Sioux Falls
Population Served: 120,000
Service Area: 70 sq. mi.
Sewer System: 578 mi. of sewer
The City of Sioux Fa I Is'sewer system consists of 578 miles of sanitary pipe. The
pipes range in size from 6-66 inches in diameter.The sewer system is divided
into 20 drainage basins, and the current maintenance program provides that
the entire system is cleaned once every three years. Maintenance records are
stored in an Oracle database that generates work orders by date and drainage
basin. Sanitary sewer maintenance includes high pressure jetting, vacuuming
to remove loosened debris, and mechanical and chemical root control. Closed circuit televising (CCTV) is used to identify trouble
spots, where more frequent cleaning is required than the scheduled three year intervals. In 2001,372 miles of sewer (64 percent of the
system) were cleaned and televised.The cost for these maintenance activities equates to $236 per 5,280 feet (1 mile) of inch-diameter
pipe . Using a ten-inch diameter pipe as an average, maintenance costs are about $0.45 per linear foot.
Con tact: Richard McKee, M. O. U. Public Works, Water Reclamation Division
FORT WORTH, TX
Sewer Cleaning Efforts
Responsible Agency: City of Fort Worth
Population Served: 880,000
Service Area: 291 sq. mi.
Sewer System: 2,589 mi. of sewer
The City of Fort Worth's sewer system consists of approximately 2,589 miles
of pipe.The pipes range in size from 6-96 inches in diameter. Ninety percent
of the system is composed of pipes with diameters of18 inches or less. The
city has established maintenance goals which include cleaning all sewers 18
inches or smaller once every eight years and all sewers larger than 18 inches
once every 15 years.The cleaning and maintenance of the smaller diameter
pipes is conducted by city employees, while the cleaning of larger diameter pipes is outsourced due to technical logistics and the
specialized equipment needed.
The sewer system is divided into nine major drainage basins containing 167 subbasins. Each subbasin, along with its SSO and
maintenance histories, is contained in a Geographic Information System (CIS) database. Spatial analysis of the CIS database is
compared to baseline performance indicators to prioritize the cleaning order of the subbasins. In 2001-2002,1.15 million linear
feet of pipe were cleaned by the city.The cost for city cleaning activities during this time, including labor and equipment, was $0.61
per linear foot (in 2002 dollars) and the cost for cleaning of larger pipes by private contractors was $1.02 per linear foot (in 2002
dollars).
Contact: Darrell Gadberry, City of Fort Worth, Water Department, Field Operations Division
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Report to Congress on the Impacts and Control ofCSOs and SSOs
References
Arbour, Rick, and Ken Kerri. 1998. Collection Systems:
Methods for Evaluating and Improving Performance.
Prepared for EPA, Office of Water Programs, Municipal
Permits and Operations Division and developed under EPA
Grant No. CX924908-01-0. Sacramento, CA: California
State University, Sacramento Foundation.
California State University (CSU), Sacramento - College
of Engineering and Computer Science, Office of Water
Programs. 2001. Operation and Maintenance of Waste-water
Collection Systems. Vol. 1, 5th ed. Prepared for EPA Office
of Water Programs, Municipal Permits and Operations
Division. Sacramento, CA: CSU, Sacramento Foundation.
EPA Office of Research and Development. 1998. Sewer and
Tank Sediment Flushing: Case Studies. Prepared by Pisano,
William C., et al. EPA 600-R-98-157.
EPA Office of Water. 1999. Collection System Oe^M Fact
Sheet: Sewer Cleaning and Inspection. EPA 832-F-99-031.
Fan, Chi-Yuan, Richard Field, William C. Pisano, James
Barsanto, James Joyce, and Harvey Sorenson. 2001.
"Sewer and Tank Flushing for Sediment, Corrosion, and
Pollution Control." Journal of Water Resources Planning and
Management. May/June: 194-201.
Mitchell, Scott E. 2001. "Benchmarking Operations for
Sewer Cleaning vs. Private Contractor - Cost Analyses,
1997-2001." Retrieved July 28, 2003.
http://www.ci.hammond.in.us/sewer/paper.html
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
0&M-12
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TECHNOLOGY
OPERATIOr
RIPTION
M Ot I V I AA MM I l_ I M
Pollution Prevention
Overview
Pollution prevention is defined as any practice that
reduces the amount of pollutants, hazardous substances,
or contaminants entering the waste stream (EPA 2002).
Pollution prevention focuses on source control, seeking to
reduce the pollutants generated by a particular process. It
relies on individual action, and therefore, public education
and awareness. A range of pollution prevention activities
including best management practices (BMPs) for fats, oils,
and grease; household hazardous waste; and commercial
and industrial facilities are detailed below.
Fat, Oil, and Grease Control Programs
Fat, oil, and grease (FOG) are a by-product of many food
items that are prepared in homes and restaurants. Often,
when used for cooking, FOG is improperly disposed of by
pouring it down a sink drain. FOG can also enter the sewer
system when dishes are washed. Over time, FOG builds up
in sewers, leads to blockages, and can cause combined and
sanitary sewer overflows (CSOs and SSOs).
Nationally, EPA believes that FOG is one of the leading
causes of SSOs contributing to approximately one out of
every five SSOs. The best way to prevent these blockages is
to keep FOG out of the sewer system. Education programs
are important in ensuring residents, institutional, and
commercial establishments, especially restaurants, are
aware of their role in managing FOG. In addition, many
municipalities have adopted regulations controlling the
introduction of FOG into the sewer system.
In commercial areas, grease traps or interceptors are often
used to remove FOG from wastewater before it enters the
sewer system. Grease traps slow the flow of wastewater,
allowing it to cool and FOG to float to the top of the trap.
Baffles are located at the beginning and end of the trap to
prevent FOG from escaping as shown in Figure 1. The size
of the trap depends on the anticipated flow and the amount
of FOG in the wastewater. Grease trap capacities range from
small units (less than 10 gallons) located in the kitchen area
to 5,000 gallon tanks installed underground outside the
Clean-out
Figure 1. A schematic showing the collection of FOG by a
grease trap located within a sewer line.
building (NCDPPEA 2002). Often, for restaurants, the size
of the trap is determined by the number of seats.
Household Hazardous Waste Management
Household hazardous waste includes products that
are corrosive, toxic, reactive, or flammable. Household
hazardous waste management focuses on the proper
application and disposal of these otherwise hazardous
materials. Common household hazardous waste are paint
thinners, auto batteries, pesticides, and oven cleaners.
Household hazardous waste collection programs highlight
the importance of proper disposal of these materials and
potential hazards resulting from improper disposal (i.e.,
pouring down kitchen sinks or storm drains and thus into
the sewer system). Collection programs typically include
schedules for home pick-up or drop-off points for the
waste.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
The inappropriate or excessive application of fertilizer and
pesticide can allow large amounts of these chemicals to
be washed off lawns and other landscaped areas during
wet weather events. Fertilizer contains nitrogen and
phosphorous that can contribute to the eutrophication
of receiving waters. Pesticides contain chemicals that are
toxic to aquatic life and can impact the biological processes
used at the wastewater treatment plant. In areas served by
combined sewers, runoff contaminated with fertilizer and
pesticides may be discharged during a CSO event. Drain
disposal of chemical remnants can also introduce the
fertilizer or pesticide into the sewer system.
Integrated pest management (IPM) programs can be
effective in limiting fertilizer and pesticide application. IPM
programs teach residents the difference between insects that
are beneficial and harmful to plants to avoid the over use of
pesticides. For example, if one branch of an azalea bush is
infected with an azalea lace bug, that branch can be cut out
of the bush eliminating the pest and reducing the need for
pesticide (NVPDC 1996). Further, IPM programs advocate
using a diverse selection of native plants and maintaining
a healthy plant bed by using organic compost instead of
fertilizer.
Commercial and Industrial Waste Management
Commercial and industrial facilities can discharge large
amounts of pollutants to sewer systems through direct
disposal or storm water runoff (EPA 1999). Pollution
prevention plans that incorporate storm water BMPs
and water conservation measures can play an important
role in reducing the pollutants discharged directly to the
sewer system, as well as those washed-off commercial
and industrial sites during wet weather events. BMPs for
commercial and industrial sites can be used to control the
volume or quality of storm water runoff. BMPs may include
using temporary covers for outside storage areas, installing
covered bays for vehicle maintenance, purchasing rain proof
dumpsters, and adopting environmentally-friendly building
and grounds maintenance practices. Water conservation
measures at commercial and industrial facilities often
include installing water efficient fixtures such as low-flow
toilets and faucets and reusing or recycling cooling water.
For more information on water conservation activities,
refer to the "Water Conservation Technology Description"
in Appendix B of the Report to Congress on the Impacts and
Controls ofCSOs and SSOs.
Key Considerations
Pollution prevention practices most often take the form
of simple, individual actions which reduce the pollutants
generated by a particular activity. Therefore, pollution
prevention programs must be implemented with broad
participation in order for there to be a discernible
reduction in pollutant loads discharged to sewer systems.
Specific considerations for each of the pollution prevention
practices described above are provided below.
Applicability
Fat, Oil, and Grease Control Programs
FOG is a common problem in both combined sewer
systems (CSSs) and sanitary sewer system (SSSs).
Numerous municipalities have invested in programs to
educate customers about the proper handling and disposal
of FOG. Education programs are most successful if they are
tailored to a specific audience (i.e., residential, institutional,
or commercial).
Education programs should make residents aware that
FOG can block private laterals, in addition to municipal
sewers, resulting in basement backups. Utility bill inserts,
direct mailings, newspaper articles, and community events
are ways to reach residential customers (NCDPPEA 2002).
Outreach materials can include a "Do and Don't" list such
as the following:
Do:
• Collect FOG in a container and dispose of it with the
trash
• Scrape grease and food from cooking/serving ware
before washing
• Encourage neighbors and friends to help eliminate
FOG from the sewers
Don't:
• Pour FOG down the sink drain or toilet
• Put greasy waste or food down garbage disposals
• Place FOG wastes in the toilet
Education for commercial and institutional customers
can take the form of workshops, mailings, and web
information. Workshops provide a forum for disseminating
information concerning environmental and health effects
of FOG, BMPs for controlling FOG, and any municipal
ordinances that pertain to FOG. Workshops can emphasize
the important link between employee behavior and possible
FOG blockages. If new ordinances are put into place, direct
mailings can be used to inform those effected of their new
responsibilities, as well as techniques for controlling FOG.
A vital part of any education program for commercial and
institutional customers is discussion of grease trap design
and maintenance. Grease traps do not remove all the FOG
in the wastewater; proper design and regular maintenance is
critical for effective grease trap performance. The effective
separation of water and grease is based on four design
criteria (NCDPPEA 2002):
0&M-14
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Operation & Maintenance: Pollution Prevention
• Sufficient volume to allow the wastewater to cool for
separation
• Proper retention time for the FOG to separate from
the wastewater
• Low turbulence to prevent FOG and solids from
resuspending
• Adequate volume to handle the accumulation of FOG
and solids between cleanings
Household Hazardous Waste Management
Programs that promote appropriate disposal of household
hazardous waste and the proper application of fertilizers and
pesticides can be instituted in any community.
Household hazardous waste collection programs provide
information to residents about materials that are considered
hazardous and provide opportunities for proper disposal.
State or local governments can establish a network of
regional, local, or mobile household hazardous waste
collection facilities providing residents with multiple options
for disposing of the waste (MPCA 2002). Municipalities may
organize simple or elaborate drop off events that incorporate
other environmental education programs.
The control of fertilizer and pesticide levels involves
convincing residents, institutions, and municipal
departments to adhere to handling and application
techniques that limit pollutant runoff. Public education
programs should emphasize that "more is not better," and
that the lowest effective dose listed on the label for any one
application should always be used. Education programs
can also include information on IPM and other alternative
pest control measures. The caretakers of large parcels of
urban land, including local park departments and other
institutions, should be encouraged to demonstrate the
responsible use of fertilizers and pesticides.
Commercial and Industrial Waste Management
The development and implementation of a pollution
prevention plan can benefit almost any commercial or
industrial facility. Pollution prevention plans can reduce
operating costs and improve the facility's public image, while
reducing the quantity of pollutants generated. Technical
assistance and incentives may also be used to encourage
commercial and industrial facilities to participate.
Some states, regional agencies, and counties have developed
programs to aid businesses in developing pollution
prevention plans. These programs typically include a waste
analysis to determine which portions of the commercial
or industrial facility's production could benefit from waste
reduction measures and services to help implement the
suggested measures.
Water conservation measures can be an important
component of a pollution prevention plan helping to
reduce the amount of water consumed by commercial and
industrial operations. This in turn reduces the amount of
water discharged to the sewer system. When establishing a
water conservation plan, a facility should perform a water
audit to survey its water use. The true cost of water usage
can then be calculated by considering the water and sewer
costs, on-site wastewater treatment costs, if any, and energy
costs to heat or pump water. After water use is characterized,
areas for improvement can be identified and prioritized.
Changes in behavior, as well as the replacement or retrofit of
equipment, can be used to implement more efficient water
use practices.
Cost
Pollution prevention measures are site-specific, and it is
therefore difficult to compare costs between programs.
Tables 1 and 2 provide cost examples for pollution
prevention practices. Table 2 specifically details commercial
and industrial pollution prevention measures including
potential cost savings.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 1. Example costs associated with pollution prevention programs.
Technology
Fats, Oil, Grease
Program
Education Program
Grease Trap/Interceptor
Typical Costs
Raleigh, NC- Budgeted $100,000 for program set-up and $50,000 annually
for implementation.
Wisconsin - Grease traps can cost $750 per cubic foot or $211,000 per
structure .2
Household Waste
Management
Hazardous Household
Waste Management
Fertilizer and Pesticide
Control
Jefferson County, KY - Operates a permanent collection facility for
hazardous household materials.The annual operation budget is $250,000
and they collect approximately 150,000 Ibs. per year ($3,333/ton or $1.677
Ib.).
Greater Detroit Resource Recovery Authority - Collected 60 tons of waste in
1995 for $223,000 ($3,716/ton or $1.86/lb.).2
Lovinia, Ml - Spent an average of $80,918 annually for their hazardous
household materials collection program from 1991-1995. The average
disposal cost was $12.19/gallon.2
Prince William County, VA- Provides soil test kits to residents for $10, which
includes analysis for fertilizer needs.2
Commercial and Industrial Waste Management
Management
King County,WA- Operates the Industrial Materials Exchange, which helps
businesses find markets for their surplus materials, wastes,and industrial by-
products.The annual operating budget is $250,000.
Waste Reduction Partners of the Land-of-Sky Regional Council, Ashland,
NC-Annual budget for 2001 was $132,097. In 2001, the program diverted
10,609 tons of solid waste from landfills.3
1 EPA 1999,2Ferguson,et al. 1997,3 Land-of-Sky 2001
Table 2. Examples of commercial and industrial pollution prevention programs.
Company State
Air Products and OH
Chemicals, Inc.
Cooper Hand NC
Tools
Frigo Cheese Wl
Corporation
Lockheed Martin GA
Quality Metal CO
Products/Sheet
Metal Shop
Small Engine Wl
Manufacturer
Unilever Home GA
and Personal
Care, Inc.
Program
Wastewater
Discharge
Reduction
Reuse Hazardous
Waste Reduction
Reuse
Hazardous Waste
Reduction
Hazardous Waste
Reduction
Hazardous Waste
Reduction
Water
Conservation Plan
Activity
Batch seal pot water is
recovered and reused
in continuous emulsion
process
Concentrate chromic acid
rinse water for reuse and
recover nickel from nickel
electroplating bast sludge
Salt whey recovery and
reuse by evaporation
Minimized paint waste
through improved planning
Installed solvent recovery
unit
Replaced chlorinated
solvents with aqueous
cleaners for parts cleaning.
Reuse of cooling water and
collected rainwater used in
the manufacturing process.
Capital
Cost
$1,000
N/A
$2,000
$4,000
$14,700
$10,000
N/A
Cost
Savings/Yr.
$2,000
$68,000
N/A
$120,649
$13,000
N/A
$20,000
Results
Reduced waste flow to sewer
system by 56% annually.
Reduced purchase of new
chromic acid by 1 0,000 Ibs.
annually. Eliminated generation
of 1 2 tons of hazardous waste
annually.
Not Available
Reduced hazardous waste
stream by 2,020 gallons
annually.
Prevented formation of 375
gallons of hazardous liquid
waste annually.
Not Available
Reduced wastewater effluent
by 77%. No longer a Significant
Industrial User in relation to
pretreatment program.
0&M-16
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Operation & Maintenance: Pollution Prevention
Implementation Examples
RALEIGH, NC
Public Education "Can Can" Campaign
Responsible Agency: City of Raleigh Department
of Public Works
Population Served: -315,000
Service Area: Not Available
Sewer System: 1,525 mi. of sewer
In 1999, the City of Raleigh passed an ordinance that made it unlawful to
dispose of grease by pouring it into the sewer system.To educate the public
about this ordinance and their responsibilities, the city launched the "Can
Can" Campaign in 2000.The city developed a website; produced television
and newspaper advertisements and radio spots; sponsored a poster contest
during the
City of Raleigh's annual Water Fest; and developed informational
brochures. The website contains information about grease and
its affect on the sewer system including a "Do and Don't" list.
The first newspaper advertisement run by the city is shown.
The city's efforts continue to educate the public on the proper
disposal of grease. Currently, a video is being developed for
civic groups and students. Public service announcements
on grease management will air on community and network
television stations. Press releases reminding citizens about
the problems grease can cause in the sewer system will also
continue. Also, water bills will contain informational inserts.
During 2001, the city experienced 51 SSO events, a 22 percent
reduction from the previous year. The city attributes this reduction
to the FOG education program and an aggressive sewer maintenance
program. The "Can Can" Program operates on an annual budget
of $50,000; the start-up cost of the program was $100,000.
DO NOT pour grease, fats or cite from coctang down the (frail
DO NOT use the totet as a wastetactol
DO NOT use the kifchersnk to (ispose of food scraps *^1
ciil qi*»tem /itHH jl if* fiofiei us* of you SMrAti^ sew& system?
Pease Ml toe Off a Ratagh Puclc Utttes DEtxrtment 390-3400
More information athttp://www.raleigh-nc.org/pubaffairs/cancan/index.htm
DENTON COUNTY, TX
Household Hazardous Waste Collection
Responsible Agency: Upper Trinity Regional Water District
Population Served: ~158,000
Service Area: Not Available
Sewer System: Not Available
The Upper Trinity Regional Water District in the Dallas/Fort Worth
area provides drinking water, wastewater, hazardous waste
management, biosolids management, and non-potable water
supply services. Approximately 13 cities have contracts with the
district for the specific services they need. In 1998, a household
hazardous waste collection program was established to provide
the district's customers with ways to dispose of their hazardous wastes in an environmental-friendly manner. The collected waste is
then transported in a specially modified cargo trailer to a regional disposal facility.The trailer was purchased in 1998 using a grant
from the Texas Commission on Environmental Quality. During collection events, residents can dropoff batteries, used car oil, solvents,
antifreeze, herbicides, pesticides, aerosols, mercury, and paint. Paint is the most disposed item.The district charges each city $80 per
participating household for disposal fees and administration costs.The first collection event was held in June 1999. In 1999,a total of
375 households handed in 51,468 pounds of material.The total cost for the participating cities was approximately $26,250.
More information at http://www.utrwd.com/HHW.HTM
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Report to Congress on the Impacts and Control ofCSOs and SSOs
ORANGE COUNTY, CA
FOG Control Study
Responsible Agency: Orange County
Sanitation District
Population Served: 2.4 million
Service Area: 470 sq. mi., 23 cities
Sewer System: 650 mi. of sanitary sewer
draft report that details the building blocks of a FOG control
studies and pilot tests of FOG control technologies.
A two-phase FOG control study is currently being conducted by
the Orange County Sanitation District.The first phase, completed
in March 2003, consists of a set of 13 building blocks that can be
used interchangeably to create FOG programs specific to local
conditions.The building blocks are grouped into four categories:
programmatic, best management practices, best available
technologies, and regional and watershed. A summary of the
program is presented.The second phase is on-going and involves field
Cost comparisons of the various technologies that will be pilot tested as part of the FOG control study are not currently
available. The first phase of the study cost $268,000. It is expected that another $1 million will be spent on pilot tests and system
characterization.
Contact: Adriana Renescu
Building blocks of Orange County Sanitation District's FOG control study.
Programmatic Building Blocks
FOG Characterization
Ordinance
Monitoring and Enforcement
Fees and Incentives
Education and Outreach
Grease Disposal Practices and
Alternatives
Description
Characterization of local FOG conditions including the extent and nature of SSO problems;
identification of current or potential "hot spots"
Provides the legal framework for implementing a FOG program; establishes monitoring requirements,
enforcement conditions, and fees.
Ensures that FOG control requirements are being followed. Enforcement: penalize entities that fail to
correctly implement FOG controls.
Fees, often in the form of increased sewer fees, pay for the FOG program. Reduced fees may be
used as an incentive if commercial and institutional establishments can prove they are successfully
implementing controls.
Many different stakeholders contribute to the success of FOG programs, it is important to identify
and target key partners. Also, it is necessary to take into consideration language barriers (multilingual
programs are required).
Best Management Practices
Kitchen BMPs Practices to reduce and eliminate residential FOG before it enters the sewer system.
Collection System Cleaning Collection system cleaning and TV-monitoring should focus on areas in the sewer system where FOG is
most problematic.
Best Available Technologies
Grease Interceptors
Passive Grease Traps
Automatic Grease Traps
Biological Additives and Services
Chemical Additives
Grease interceptors located outside of buildings that have a minimum volume of 750 gallons.
Small collection devices with volumes less than 50 gallons, which are installed under sinks and must be
cleaned manually.
Automatic grease traps are self-cleaning.
Biological additives digest FOG and prevent it from blocking sewer lines or overloading traps.
Chemical additives break down FOG and have been found to be useful in solving lift station grease
problems.
Regional and Watershed
Once FOG controls have been put in place, there must be grease disposal mechanisms available to
customers. Such disposal methods include converting grease into biofuels and feeding the waste into
POTW digesters. Also, it is important to regulate haulers and disposal sites to avoid illicit dumping.
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Operation & Maintenance: Pollution Prevention
PRINCE WILLIAM
COUNTY, VA
Horticulture and Water Quality Program
Responsible Agency: Prince William County
Cooperative Extension
Since the early 1990s, the Prince William County Cooperative Extension has
administered a water quality program that educates residents about the
effects of over fertilizing their lawns and using too many pesticides. Residents
are recruited using direct mailings and programs with civic and homeowner
associations. Once a resident registers with the program,they complete a pre-program survey and attend educational seminars such
as "Fall Fertilization" and "IPM Basics! Upon completing the program, a master gardener volunteer visits with the residents to ensure
that they are implementing the IPM and fertilization practices correctly. Finally, the resident completes a post-program survey.To
date, over 2,000 households have completed Prince William's turf care and management program.To determine the effectiveness of
the program, Prince William compared 1996 survey results from 600 participating households pre- and post-program. Results of the
survey is summarized below.
Turf care and management program participant responses.
Participant Activities
Tested soil to determine fertilizer rates
Linked excessive nutrients to water quality problems
Considered IPM to be important
Followed a fall fertilization schedule
Pre-Program
17%
60%
42%
50%
Post-Program
78%
86%
62%
82%
The survey results showed reductions in fertilizer and pesticide application.The average amount of nitrogen applied to lawns was
reduced by 40 percent, pesticide and water use were reduced by 25 percent, and the volume of yard trimmings sent to the landfill
was reduced by 25 percent.The program is facilitated by a part-time water quality technician and master gardener volunteers. Prince
William County's operating cost for the program ranges between $5,000-$10,000 annually. Except for the $10 soil test, the program is
free for residents.
More information at http://www.co.prince-william.va.us/vce/enr/enr.htm
WINSTON-SALEM, NC
Ultra filtration for Pollution Prevention
Responsible Agency: Sara Lee Knit Products Corporation Sara Lee Knit Products Corporation produces an array of finished
textiles, many of which include cotton material dyed with reactive
dyestuff. Cotton dying produces large waste streams, composed
mostly of color and salt.The dyestuff has a low affinity to the cotton fabric, even with the help of the salts used to bind the color to
the fabrics. Almost all of the salt and approximately half of the dye ends up in discharges to the sewer system.
To reduce the amount of chemicals purchased and wastewater generated, Sara Lee Knit Products investigated a pilot-scale
ultrafiltration and nanofiltration system.The filtration system separates the salts from other impurities for reuse and generates
a concentrated color waste stream that can be more efficiently treated. The pilot study revealed that the system removes most
pollutants of concern while allowing sodium chloride to remain in the permeate. Also, the polymer treatment scheme applied to
the filtrate was successful and economical.
Projections from the pilot study suggest that the facility, which generates 240,000 gallons per day of wastewater, would reduce its
water use by 120,000 gallons per day and salt discharges by 26,000 pounds per day.The filtration system will remove an estimated
60 percent of the dyestuff and 50 percent of the salt typically discharged. The total capital cost for the filtration and treatment
system would be $990,000 with annual operating costs of $180,000. Savings on salt purchases were estimated at $335,000 annually.
An additional annual savings of $460,000 could be achieved using the color removal process.
Contact: Donald Brown, Sara Lee Knit Products Corporation
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Report to Congress on the Impacts and Control ofCSOs and SSOs
References
EPA Office of Prevention, Pesticides, and Toxic Substances.
2002. "Definitions National Prevention Pollution Policy."
Retrieved November 22, 2002.
http://www.epa.gov/p2/p2policy/definitions.htm.
EPA Office of Water. 1999. Combined Sewer Overflow
Management Fact Sheet: Pollution Prevention. EPA 832-F-
99-038.
Ferguson, T. et al. 1997. "Rouge River National Wet Weather
Demonstration Project: Cost Estimating Guidelines
Best Management Practices and Engineering Controls."
Retrieved December 9, 2002.
http://www.rougeriver.com/pdfs/stormwater/srlO.pdf.
Land-of-Sky Regional Council. 2001. "Waste Reduction
Partners Annual Report 2001." December 10, 2002.
(Retrieved July 10, 2003.)
http://www.landofsky.org/publications/annual_report2001/
default.htm.
Minnesota Pollution Control Agency (MPCA). 2002.
"Household Hazardous Waste." Retrieved November 25,
2002.
http://www.pca.state.mn.us/waste/hhw.htmltmap.
North Carolina Division of Pollution Prevention
and Environmental Assistance (NCDPPEA). 2002.
"Considerations for the Management of Discharge of Fats,
Oil, and Grease (FOG) to the Sanitary Sewer Systems."
Retrieved November 22, 2002.
http://www.p2pays.org/ref/20/19024.pdf.
Northern Virginia Planning District Commission
(NVPDC). 1996. Nonstructural Urban BMP Handbook.
Prepared for the Department of Conservation and
Recreation/Division of Soil and Water Conservation.
Annandale, VA: NVPDC Coastal and Chesapeake Bay
Program.
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
0&M-20
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\M
RIPTION
M Ot I V I AA MM I l_ I M AA I M
%fa&frf$ Monitoring, Reporting,
^f*?'S and Public Notification
\v^
Overview
Operation and maintenance practices are intended to
enhance sewer system performance and minimize or
reduce the occurrence of CSOs and SSOs and the potential
impacts they have on receiving waters. Monitoring, public
notification, and reporting of CSOs and SSOs and their
impacts do not directly accomplish these objectives, but
they are essential to:
• Understand sewer system performance and impacts of
CSOs and SSOs on receiving waters;
• Provide the potentially impacted public with
information about overflow locations, specific events,
and performance trends;
• Improve oversight by the National Pollutant Discharge
Elimination System (NPDES) authority; and
• Improve operations and maintenance (O&M) program
efficiency.
Monitoring Techniques
Monitoring of both the sewer system and receiving waters
provides valuable information for the operation and
maintenance of sewer systems and the control of CSOs and
SSOs. Monitoring provides knowledge of:
• The hydraulic characteristics of a sewer system and
how it responds to a range of rainfall events; and
• The degree of impact caused by CSOs and SSOs on
receiving waters.
Results from monitoring programs can also be used to
track improvements associated with control efforts. The
basic components of a monitoring program include:
• Rainfall;
• Sewer system flows and overflow frequency, duration
and magnitude; and
• Water quality in both CSOs and SSOs and receiving
waters.
Techniques for monitoring each of these components are
briefly described below. Additional guidance on monitoring
can be found in Combined Sewer CSOs and SSOs: Guidance
for Monitoring and Modeling (EPA 1999).
Rainfall
Precipitation is the primary cause of CSOs and a
major contributor to SSOs. Consequently, rainfall
measurements are an integral part of a monitoring
program.
Monitoring rainfall is fairly simple and provides
valuable information in assessing the response of a
sewer system to various rainfall events. Advanced
techniques that merge radar data with rain gage data
are available and can provide better rainfall estimates
than either radar or a rain gage can provide alone.
Sewer System Flow
Flow measurements in the sewer system provide
essential information related to the magnitude,
duration, and frequency of CSOs and SSOs. This
information can be used to design structural controls
and to better operate and maintain the system, all in an
effort to reduce CSOs and SSOs. Flow measurements
following construction of controls and improved
O&M practices can be used to assess the performances
of controls and track improvements. Techniques
for measuring flow in sewer systems vary greatly in
complexity, expense, and accuracy.
Manual methods are the simplest technique for
measuring flow and are most useful for instantaneous
flow measurement or for determining whether or not
an overflow occurred during or between measurements.
Manual methods can be labor intensive and do not
provide continuous flow records.
Primary flow devices control flow in a portion of a
pipe such that the flow rate can be calculated from
flow depth. Relationships between depth and flow are
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Report to Congress on the Impacts and Control ofCSOs and SSOs
accurate as long as surcharging or backflow does not
occur. Manual or automatic measurements of the depth
can be made. Depth-sensing devices can be used to
measure water depth behind a primary flow device to
determine flow rates.
Velocity meters use ultrasonic or electromagnetic
technology to sense the velocity of flow in the sewer
system. The velocity measurement is combined with
a depth measurement from a depth-sensing device to
calculate flow rates. Velocity meters can be used without
the need for a primary flow device and in situations
where surcharging or backflow occurs.
Pressurized flow rates can be estimated from the length
of time pumps are on and the specifications for the
pumps. Alternatively, full pipe flow can be measured
using orifices, venturi flow meters, flow nozzles,
turbines, and ultrasonic, electromagnetic, and vortex
shedding meters.
Water Quality
Monitoring water quality in both the sewer system and
receiving waters provides essential information for:
• Characterizing CSOs and SSOs
• Assessing the attainment of water quality standards
• Defining baseline conditions
• Assessing the relative impacts of CSOs and SSOs
on receiving water quality
Water quality monitoring programs can also be used to
track improvements associated with control efforts.
Data characterizing the water quality in the sewer
system and receiving waters during both dry and wet
weather conditions is needed. The water quality data
can be analyzed to identify pollutants of concern, their
concentrations, and likely sources of such pollutants.
Pollutant concentrations along with sewer system
flows can be used to calculate pollutant loadings to the
receiving waters.
In addition to pollutant characteristics, monitoring in
the receiving waters may include:
• Biological assessment (including habitat
assessment)
• Sediment monitoring (including metals and other
toxics)
• Flow conditions
In many cases, the primary parameter of concern
with respect to CSOs and SSOs will be pathogens,
represented by an indicator bacteria such as fecal
coliform or E. coli. Observations of floatables,
objectionable deposits, or algal growths may also
provide relative measures of CSO and SSO impacts.
Two distinct types of water quality samples can be
collected:
• Grab samples: a discrete, individual sample
representing the conditions at one location at the
time the sample is taken.
• Composite samples: a combination of samples
collected over a period of time from one location
or combination of samples from more than one
specific location.
Grab and composite samples can be collected using
either manual or automatic sampling methods. Manual
samples are collected by a trained individual using
a hand-held container. Automated samplers can be
programmed to collect multiple discrete samples as
well as single or multiple composited samples. Many
automated samplers can be connected to flow meters
that will activate flow-weighted compositing programs,
and some samplers are activated by inputs from rain
gages.
A Quality Assurance Project Plan (QAPP) is an essential
component of any monitoring program to ensure
precise, accurate, and reliable data. EPA guidance for
the development of a QAPP should be followed (EPA
2002c). The QAPP should address field sampling
methods and protocols as well as laboratory analytical
methods and quality assurance/quality control (QA/
QC). Data management techniques and responsible
personnel should also be addressed in a QAPP.
Public Notification
Public notification programs provide information to the
potentially impacted community regarding the occurrence
of CSO and SSO events and on-going efforts to control
the discharges. The Nine Minimum Controls (NMC)
outlined in EPAs CSO Control Policy specifically require
implementation of a public notification program to ensure
that the public receives adequate notification of CSO
occurrence and CSO impacts. Public notification programs
can assume a variety of forms, including posting temporary
or permanent signs where CSOs and SSOs occur (Figure 1),
coordinating with civic and environmental organizations,
distributing fact sheets to the public and the media, and
stenciling storm drains. Notices in newspapers are required
to report occurrences of CSOs or SSOs in some states.
Radio and TV announcements may be appropriate for
CSOs or SSOs with unusually severe impacts. Distribution
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Operation & Maintenance: Monitoring, Reporting, and Public Notification
of information on websites is another technique that is
rapidly gaining wider use.
Posting Signs
Signs are one of the most common mechanisms used to
communicate the potential hazard posed by CSO and
SSO discharges. Signs can be posted in the area where
the use is affected (e.g., along a beach front) or at select
public places (e.g., a public information center at a park
where recurrent SSOs have occurred). EPA specifically
recommends posting at visible CSO outfalls and in
locations where affected shoreline areas are accessible
to the public. In addition to notifying the public of the
potential risk of exposure to CSO or SSO discharges,
signs may provide contact information for citizens
interested in obtaining additional information or to
submit concerns. Call centers may be established to
receive sign-prompted calls.
WARNING
Possible Sewage
^During aad Following Haauy Rain
Figure 1. CSO warning sign (King
County, WA)
Coordinating with Civic Organizations
There are a number of ways that a municipality can
involve public interest or civic and environmental
groups in various aspects of programs to control CSOs
and SSOs. One way is to involve the public in the
process of evaluating technologies for controlling CSOs
and SSOs. Involvement in assessing willingness to pay,
determining the implementation schedule, and selecting
or modifying the method of financing for the controls
are other ways to involve these groups. Public meetings
or hearings allow public interest or civic groups to
officially comment or pose questions to the municipality
regarding a control program.
For example, the State of Wisconsin organized a
workgroup including representatives from state and local
health departments and citizen groups with an interest
in beach health. This group worked to gather data on
beach use and potential sources of contamination. They
also interviewed beachgoers and collected suggestions
for improvement of beach health. As a result of
this program, Wisconsin's 180 coastal beaches were
categorized into high, medium, and low priority based
on popularity and risk of contamination by sources
including CSOs and SSOs. Higher priority beaches
are tested more frequently, including 25 high-priority
beaches that are tested five times per week. Every day, the
high-priority beaches post one of three signs to advise
beachgoers of water quality for that day- good, poor,
or closed. In addition, bathers can also check a website
to view daily water quality reports for all high-priority
beaches along the Great Lakes.
Distributing Fact Sheets
Another method of outreach to the public is through
the dissemination of fact sheets on CSOs and SSOs.
Municipalities often use these fact sheets to describe
what CSOs or SSOs are, address specific local issues,
and discuss impacts to local water bodies. Local issues
addressed in the fact sheets can include disconnecting
downspouts from the sewer system, local monitoring
programs, and system improvements that are planned
or are being implemented to address CSOs and SSOs.
Fact sheets can also be developed to target specific
commercial or industrial sewer customers encouraging
best management practices, explaining regulatory
requirements, or highlighting important pollution
prevention measures.
EPAs Office of Wastewater Management has also
developed a series of outreach materials and fact sheets
to help municipalities educate citizens on important
wastewater issues. These materials are available online
at: http://cfpub.epa.gov/npdes/wastewatermonth.cfm.
The materials include space to insert local contact
information for citizens to find more information. Local
governments can inexpensively produce custom versions
of the materials with their own addresses and phone
numbers.
Stenciling Storm Drains
Storm drain stenciling is frequently used in separate
storm sewer systems to educate the public that wastes
disposed of in storm drains flow directly to receiving
waters without treatment. Similarly, municipalities with
CSSs can use storm drain stenciling as part of a public
0&M-23
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Report to Congress on the Impacts and Control ofCSOs and SSOs
education program (Figure 2). Stenciling the name of
the water body to which the street inlet drains provides
a concrete link to the public to the consequences
of dumping or littering. Storm drain stenciling
programs can also generate useful information for the
municipality. Since cities often have more storm drain
inlets than can be efficiently inspected by city staff,
program volunteers may be asked to note drains than
\ ' 1JIUIXS Til STRUM I
Figure 2. Community education on the
importance of storm drain stenciling (King
County, WA)
are clogged with debris or show signs of dumping.
The municipality can then target these drains for
maintenance.
Reporting
An essential element of a proper O&M program is
documentation of accurate and reliable records related
to CSOs and SSOs. Reporting requirements related to
CSO and SSO events are typically included in the NPDES
permit issued to a wastewater utility. Current reporting
requirements for CSOs and SSOs are not always consistent
from state-to-state; however, reporting typically involves
notifying the appropriate regulatory agencies in a timely
manner after a CSO or SSO event. Several states require
that the duration and frequency of every CSO event be
reported in a discharge monitoring report and submitted
on a monthly basis. Twenty-four hour oral reporting of
SSO events is generally required, and must be followed by a
written report within five days of the SSO event. States may
also require an annual report estimating the volume of CSO
or SSO discharged over the past year, identifying known or
potential water quality impacts, and, in the case of SSOs,
the cause of the spill. Several states compile information
on reported SSO events in databases or spreadsheets; at
least two states, Michigan and Maryland, publish lists of
reported CSO and SSO events on their websites.
The CSO Control Policy states that the municipality should
submit to the NPDES permitting authority documentation
on the implementation of the NMC. Documentation
should include information that demonstrates:
• The alternatives considered for each minimum control
• The actions selected and the reasons for their selection
• The selected actions already implemented
• A schedule showing additional steps to be taken
• The effectiveness of the minimum controls in
reducing/eliminating water quality impacts.
The Guidance for Nine Minimum Controls (EPA 1995)
presents examples of the information that should be
documented for the NMCs.
Key Considerations
Responsibility for monitoring, public notification, and
reporting efforts is often shared by a number of agencies
within a single jurisdiction. These can include:
• Wastewater utility operators
• City, county, or state health department
• City, county, or state environmental agencies
• Drinking water providers
• Public works departments
This potential overlap can lead to a duplication of efforts
(e.g., multiple agencies monitoring water quality conditions
in a single location). Good communication between these
agencies can help ensure cost-effective data collection and
a coordinated response to those CSO and SSO events with
potential to impact the environment or human health.
Other key considerations related specifically to monitoring,
public notification, and reporting are discussed below.
Monitoring
Developing the extent of the monitoring program and
selecting the most appropriate monitoring techniques will
depend on site characteristics, budget constraints, and
availability of trained personnel. The development of the
monitoring program should be closely coordinated with the
NPDES permitting authority to make sure that monitoring
results will be acceptable and satisfy the regulatory
requirements. Some specific considerations for monitoring
rainfall, sewer system flow, and water quality are discussed
below.
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Operation & Maintenance: Monitoring, Reporting, and Public Notification
Rainfall
Rainfall conditions may vary significantly over a sewer
system. Sufficient rain gages should be located to
provide data representative of the entire study area.
Rain gages should be located in open spaces away
from trees or buildings that may shield the gage from
rainfall. Installing the gages at ground level is preferred,
rooftops are also an option. Police and fire stations
and other public buildings are desirable locations as
vandalism is prevented.
Sewer System Flow
Monitoring flows in sewer systems can be difficult
because of surcharging, backflow, tidal flows, and
the intermittent nature of CSOs and SSOs. Although
some metering installations are designed to operate
automatically, they are prone to clogging in sewer
systems and should be checked as often as possible.
Monitoring locations should be selected to identify
which structures in the sewer system limit hydraulic
capacity and should target portions of the system
that are most likely to have CSOs and SSOs or receive
significant pollutant loadings. A representative range
of land uses and basin sizes should be monitored. As
many overflow outfall locations as possible should be
monitored with an emphasis on discharges to sensitive
areas. Flow measurement devices can be rotated
between locations to obtain more comprehensive
coverage of the sewer system.
For CSOs and SSOs dependent on rainfall, a sufficient
number of storms should be monitored to accurately
predict the sewer system's response to a range of rainfall
conditions.
Water Quality
Flow-weighted composite samples should be collected
from the sewer system or outfalls to determine the
average pollutant concentration from an overflow
event (also known as the event mean concentration or
EMC). Discrete samples from the same location over
the course of an overflow can help determine whether
a pattern of pollutant concentration exists, such as a
first-flush phenomenon. A range of rainfall events and
receiving water conditions should be monitored.
In developing a water quality monitoring plan, the
location and impacts of all sources of pollutant
loadings should be considered, and monitoring
locations should be selected to isolate the impacts
from CSOs and SSOs as best as possible. Monitoring to
characterize the pollutant loadings from sources other
than CSOs and SSOs may be needed. Sensitive areas
should be given priority for monitoring, such as waters
with drinking water intakes or recreational uses. The
implementation of water quality monitoring programs
should be a high priority at beaches or recreational
areas directly or indirectly affected by CSOs and
SSOs due to the increased risk of human contact
with pollutants and pathogens. Finally, the safety and
accessibility of monitoring locations should be given
consideration.
One of the key considerations related to conventional
water quality monitoring is the lag time between
collecting water samples and providing the public
with results. This lag is due to the time it takes (from
24 to 72 hours) to test for the presence of bacterial
indicators of CSO or SSO contamination. During this
time, pathogen levels, weather, and water conditions
may change, and related environmental or human
health risks may also change. This means that decisions
regarding beach and recreational water postings,
closings, and reopenings using bacterial indicators
often reflect conditions as they were one to three days
earlier (EPA 2002). Further, contaminants may no
longer be present once test results are available and
safe beaches may be posted needlessly. Recent studies
of southern California beach closures showed that 70
percent of the postings of water quality exceedences last
less than one day, meaning that water quality is likely to
have already returned to acceptable levels by the time
laboratory results are available and warning signs are
posted (Leecaster and Weisberg 2001).
To address this time lag problem, a number of
municipalities are using time-relevant water quality
monitoring and receiving water quality models. These
techniques seek to shorten analysis times, use quicker
predictive methods, and communicate water quality
information to the public on a timely (e.g., near-daily)
basis so the public can make more informed decisions
regarding recreational water use (EPA 2002). Specific
activities undertaken to support these objectives
include monitoring more frequently or at additional
locations, using analytical methods that provide
results sooner, using a predictive model to supplement
monitoring, and improving public notification
programs.
Public Notification
The principal advantage of a public notification program
is the potential to reduce exposure of the general public to
health risks associated with exposure to CSOs and SSOs.
Well-designed public notification programs also offer
wastewater utilities an opportunity to educate customers
and seek assistance from the public in identifying problems,
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Report to Congress on the Impacts and Control ofCSOs and SSOs
such as dry weather CSOs and SSOs. It can be challenging,
however, to interest and involve the public in municipal
efforts to control CSOs and SSOs.
Public notification programs may be developed
cooperatively with other agencies and organizations
including city, county, or state health departments;
shoreline owner associations; boating and fishing
associations; or local planning and zoning authorities.
Cooperative efforts can be a valuable mechanism for
leveraging resources, as well as enhancing the quality,
credibility, and success of public notification programs
(EPA 2002). Experience shows that it may also be valuable
for the wastewater utility to establish a relationship with
the local media to help promote efforts to control CSO
and SSO events, as well as to distribute time-relevant
recreational water quality information. More extensive
experience working with the local news media can also help
ensure minimal misinterpretation regarding the occurrence
of CSO and SSO events.
The public is often not interested in the details behind
the monitoring project, but rather if the water body is
safe to use. Therefore, it is important that information
is disseminated in a clear and concise format so that
the public can consider the relative risk associated with
exposure to the water body. Unless beachgoers are informed
about current water quality conditions in a particular
area, they will be unable to make informed choices about
destinations or how to avoid exposure to pollutants, if
necessary.
Reporting
The timely reporting of CSO and SSO events is a regulatory
requirement; therefore, penalties are assessed for failing to
report. It is important to maintain regular communication
with the regulatory authority to ensure that submissions
comply with permit requirements and meet the
expectations of the permitting authority.
As municipalities, NPDES permitting authorities, and
the public undertake efforts to control CSOs and SSOs,
consideration should be given to developing and reporting
on performance measures such as:
• End-of-pipe measures that show trends in the
discharge of CSOs and SSOs, such as reduction in
pollutant loadings and the frequency, duration, and
magnitude of CSOs and SSOs;
• Receiving water measures that show trends in relevant
water quality parameters, such as bacteria and
dissolved oxygen concentrations; and
• Measures of the use of the receiving waters including
beach closures, shellfish bed closures, and fish
populations.
• Administrative measures that track programmatic
activities;
Reporting on performance measures will allow
municipalities, states, and EPA to demonstrate the benefits
and long-term success of CSO and SSO control efforts.
Cost
The cost of monitoring will vary greatly based on the size
and complexity of the sewer system and receiving waters,
the number of CSO and SSO events that occur, and the
techniques used. The costs of monitoring can be significant,
especially for a large sewer system, a large number of
outfalls, or frequent occurrences of CSO or SSO events.
A small scale monitoring program may necessitate more
conservative assumptions or result in more uncertainty
when reporting on overflow events and when selecting
and designing CSO or SSO controls. It should be noted
that large sums of money spent on monitoring should be
avoided if the additional data will not significantly enhance
understanding of how a sewer system responds to a range
of rainfall events, and to what extent receiving waters are
impacted by CSOs and SSOs.
Analysis of water samples for the presence of indicator
bacteria typically costs about $35 per sample (EPA 2003).
Bacteria data tend to be highly variable; therefore, samples
may need to be collected in duplicate or triplicate from a
single location. Additionally, if a CSO or SSO event occurs
over an extended period of time, multiple samples may
need to be collected over time.
EPA believes that, in general, costs for public notification
programs should be nominal (EPA 1995), but will vary
with the size of the potentially-impacted population. Costs
for reporting should be nominal as well, if a well-designed
O&M plan is carried out.
0&M-26
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Operation & Maintenance: Monitoring, Reporting, and Public Notification
Implementation Examples
NARRAGANSETT BAY, Rl
Responsible Agency: Rhode Island Department of Health
Population Served: 360,000
CSOs have historically caused use restrictions in large
areas of the upper Narragansett Bay.There are several
beach areas in the upper bay that are used by the
public for swimming, diving, and water skiing. The
occurrence of recreational use in areas with use restrictions is a public health concern.
To address this public health issue, the Rhode Island Department of Health's (RIDOH's) Beaches Monitoring Project samples 23
sites in the upper bay. RIDOH conducts weekly beach monitoring from mid-May through mid-September to coincide with the
summer beach season. Beaches are closed based on exceedances of bacterial water quality standards. RIDOH also closes beaches
preemptively, without waiting for sampling results,if a CSO or SSO occurs near a beach. If a beach is closed because of high bacteria
levels, it is resampled daily until bacteria levels fall below the water quality criteria. The beach is reopened if five consecutive
samples are collected at least 24 hours apart that are at or below the bacterial water quality standard. Upon reopening, at least
three samples are collected each week for three months.The public is notified of beach closures using the following procedures:
• Appropriate municipal and state officials are notified
• An advisory or closure notice is posted at the beach, as needed
• A press release is issued and the project website and hotline are updated with current conditions
Many of these sites sampled were found to display consistently poor water quality, exceeding the state bacteria standard more
than 50 percent of the time.
More information at: http://www.health.state.ri.us/environment/beaches/index.html
KING COUNTY, WA
Responsible Agency: King County Wastewater
Treatment Division
Population Served: 1.3 million
Service Area: 420 sq. mi.
Sewer System: 275 mi. of sewer
The King County Wastewater Treatment Division works jointly with the
Seattle Public Utilities and the Seattle-King County Health Department in
posting warning signs at CSO locations and undertaking public outreach.
The Health Department maintains a CSO information line and website to
answer any health concerns about CSOs or questions such as,"How long
does water stay contaminated after a discharge?" In early 1999, King County
and the City of Seattle posted signs near CSO outfalls.The signs warn people
not to swim or fish at these outfalls during or following rainstorms.The signs also include the phone number of the CSO Information
Line operated by the Seattle-King County Health Department.The Health Department recommends that people not go in the water
near these signs for 48 hours after a heavy rain.
Contact: Bob Swarmer, King County Wastewater Treat,emt Division
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Report to Congress on the Impacts and Control ofCSOs and SSOs
PITTSBURGH/
ALLEGHENY COUNTY, PA
Responsible Agency: Allegheny County Health Department
Population Served: 850,000
Service Area: 311 sq.mi.
Sewer System: 85 mi. of interceptor sewer
The Allegheny County Health Department (ACHD)
implemented a public notification program designed to
warn the public of possible river contamination as a result
of CSO events, and advise limited contact while engaging
in recreational activities on the river during periods
immediately following wet weather events. The frequency
and duration of the alerts varies depending on the amount of
rainfall. ACHD publishes river water advisories in local newspapers and produces public service announcements on local television
stations to educate the public of the dangers attributable to the CSO discharges. When an alert is in effect, marinas, docks, and other
sites along the rivers fly an orange-colored flag with black CSO lettering.Thirty-four sites participated in the program during the 2003
recreation season-seventeen on the Allegheny River,eight each on theMonongahelaand Ohio Rivers,and one on theYoughiogheny
River.The flags are lowered when "safe" levels have returned.The public can also call the river water advisory hotline or visit the ACHD
website to obtain updates 24 hours a day.
Thirteen alerts were issued during the wet summer of 2002, lasting 83 days altogether or an average of six days each. By contrast,
during the dry summer of 1999,11 alerts were issued and lasted a total of 33 days or an average of three days each.
More information athttp://www.achd.net/
BOSTON. MA
Responsible Agency: Charles River Watershed
Association, Metropolitan District Commission,
and Massachusetts Water Resources Authority
One of the monitoring objectives of the Charles River Basin/Boston Harbor
Beaches Project was to develop a predictive model that would supplement the
water quality monitoring program and provide quick, conservative estimates
of bacteria levels at four Boston Harbor beaches.The four beaches are sampled
seven times per week; rain gages have been installed close to the beaches.
Analysis of data collected at the beaches showed that the previous day's rainfall was a better predictor of water quality than the
previous 24-hour bacteria measurement.Therefore,a simple rainfall model was developed for each of the beaches,and combined
results from the rainfall model and bacteria monitoring are used to determine when to post the beaches. Beaches are reopened only
when monitoring results indicate attainment of the bacterial water quality standard.The project uses several different types of public
notification techniques to communicate the results of the monitoring prog ram.These include:
• Availability of daily water quality conditions on the Metropolitan District Commission website
• A telephone hotline that provides updated water quality conditions for Boston Harbor beaches on a daily basis
throughout the beach season
• Posters, water bottles,and brochures that explain and highlight the beach monitoring program
• Notification and other communications with the Massachusetts Department of Public Health and local boards of health
More information at http://www.crwa.org
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Operation & Maintenance: Monitoring, Reporting, and Public Notification
References
Allegheny County Health Department. "Topic: Water
Pollution - Surface and Underground Sources of Water."
Retrieved June 3, 2003.
http://trfn.clpgh.org/achd/sewage.html.
Bartram, J., and G. Rees, eds. 2000. Monitoring Bathing
Waters: A Practical Guide to the Design and Implementation
of Assessments and Monitoring Programmes. London and
New York: E&FNSPON.
Boehm, A.B., et. al. 2002. Decadal and shorter period
variability and surf zone water quality at Huntington Beach,
California. Environmental Science and Technology. 36:3885-
3892.
Citizens Environmental Research Institute (CERI). 1999.
Assessment Strategy for Evaluating the Environmental and
Health Impacts of Sanitary Sewer CSOs and SSOsfrom
Separate Sanitary Sewers. EPA Cooperative Agreement CX-
824848-01-1.
EPA Office of Water. 1995. Combined Sewer CSOs and SSOs:
Guidance for Nine Minimum Controls. EPA 832-B-95-003.
EPA Office of Wastewater Management. 1999. Combined
Sewer CSOs and SSOs: Guidance for Monitoring and
Modeling. EPA 832-B-99-002.
EPA Office of Water. 2001. Report to Congress:
Implementation and Enforcement of the Combined Sewer
Overflow Control Policy. EPA 833-R-01-003.
EPA Office of Water. 2001a. Source Water Protection
Practices Bulletin: Managing Sanitary Sewer CSOs and
SSOs and Combined Sewer CSOs and SSOs to Prevent
Contamination of Drinking Water. EPA 916-F-01-032.
EPA Office of Research and Development and Office of
Water. 2001. National Coastal Condition Report. EPA 620-R-
01-005.
EPA Office of Research and Development. 2002a. Time-
Relevant Beach and Recreational Water Quality Monitoring
and Reporting. EPA 625-R-02-0017.
EPA Office of Water. 2002b. National Beach Guidance and
Required Performance Criteria for Grants. EPA-823-B-02-
004.
EPA Office of Environmental Informantion. 2002c.
Guidance for Quality Assurance Project Plans (EPA QA/G-5).
EPA 240-R-02-009.
EPA Office of Water. 2003. Guidelines establishing test
procedures for the analysis of pollutants; analytical
methods for biological pollutants in ambient water: Final
rule. Federal Register 68, no. 139, July 21, 2003.
King County Department of Natural Resources and
Parks Wastewater Treatment Division. "The CSO
Control Program." Retrieved June 3, 2003. http://
www.dnr.metrokc.gov/wtd/cso/page02.htm.
King County Department of Natural Resources and Parks
Wastewater Treatment Division. March 2002. "Regional
Wastewater Services Plan - Water Quality Report." Retrieved
October 1, 2003.
http://dnr.metrokc.gov/wtd/rwsp/documents/WQ2002.pdf.
King County Department of Natural Resources and
Parks Wastewater Treatment Division. 2002. "2001/2002
Combined Sewer Overflow Report." Retrieved October 1,
2003.
http://dnr.metrokc.gov/WTD/cso/2001-02-intro.htm.
Leecaster, M.K., and S.B. Weisberg. 2001. Effect of sampling
frequency on shoreline microbiology assessments. Marine
Pollution Bulletin 42:1150-1154.
Southern California Coastal Water Research Project
(SCCWRP). 2003. "Research Plan 2003-2004." Retrieved
July 7, 2003.
http://www.sccwrp.org/about/rspln2003-2004.html.
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
0&M-29
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RIPTION
Collection
ntrols
Maximizing Flow to
Treatment Plant
Overview
Maximizing the amount of wet weather flow transported
to the wastewater treatment plant (WWTP) is a common
technique for reducing the volume and frequency
of CSO and SSO discharges. Maximizing the use of
existing facilities to treat wet weather flows that would
otherwise overflow without treatment is constructive in
all circumstances. The various technologies available for
maximizing the amount of flow conveyed to the WWTP
include minimum measures that can be implemented
without capital investment, and more capital intensive
projects that require planning, design, and construction.
Maximizing flow to the WWTP is one of the nine
minimum controls (NMC) established under EPA's 1994
CSO Control Policy. As an NMC, maximization of flow
to the WWTP includes measures that do not require
significant engineering studies or major construction.
Simple modifications to existing facilities such as
adjustment of regulators to divert more flow to the WWTP
can be done rather inexpensively. The CSO Control Policy
Table 1. Considerations in maximizing flow to the WWTP.
Location Measures
Sewer System Determine the capacity of the major interceptor(s) and pumping station(s) that deliver flows to the
treatment plant.
Treatment Plant Develop cost estimates for any planned physical modifications and any other additional operations
and maintenance (O&M) costs at the treatment plant due to increased wet weather flow.
Compare the current flows with the design capacity of the overall facility, as well as the capacity of
individual unit processes. Identify the location of available excess capacity.
Determine the ability of the facility to operate acceptably at incremental increases in wet weather
flows and estimate the effect on theWWTP's compliance with the effluent limits in its permit.
For example, increased flows may upset biological processes and decrease performance for an
extended period after the wet weather flows have subsided.
Determine whether inoperative or unused treatment facilities on the WWTP site can be used to
store or treat wet weather flows.
Analyze existing records to compare flows processed by the plant during wet weather events and
dry periods and determine the relationships between performance and flow.
also encourages municipalities to consider use of WWTP
capacity for CSO control as part of developing a long-
term control plan (LTCP). In doing so, municipalities may
consider more capital intensive measures to maximize the
wet weather flow delivered to the WWTP, including pump
station enhancements and construction of relief sewers in
areas with insufficient system capacity.
Many of the techniques for maximizing flow to the WWTP
specifically referenced and expected for combined sewer
systems (CSSs) have broad utility and can also be applied
to sanitary sewer systems (SSSs). EPA recommends that
the measures listed in Table 1 be considered as part of any
effort to maximize flow to the WWTP (EPA 1995).
Effective implementation of controls to maximize flow
to the WWTP requires a thorough understanding of the
sewer system and how it functions during wet weather. This
often includes a concurrent assessment of the sewer system
and treatment plant operations to ensure that increased
flows do not have adverse consequences, such as flooding
within the system or at the WWTP, or upset of biological
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Report to Congress on the Impacts and Control ofCSOs and SSOs
treatment processes. This technology description is focused
on the modifications and operational changes within the
sewer system. Specific measures discussed include:
• Regulator adjustments
• Pump station operation and maintenance practices
• Sewer system operation and maintenance practices
• Conveyance capacity evaluations
• Real-time control and monitoring
Additional information on optimizing WWTP
performance during periods of wet weather is presented
in the "Plant Modifications Technology Description" in
Appendix B of the 2003 Report to Congress on the Impacts
and Control of Combined Sewer Overflows and Sanitary
Sewer Overflows.
Regulator Adjustments
Simple modification to regulating devices in CSSs,
such as weirs, can be useful in maximizing flow to
the WWTP. Adding stop planks or raising brick/
concrete weirs through the construction of either
temporary or permanent structures, can increase the
volume of wet weather flows stored in the CSS and
eventually delivered to the WWTP for treatment. Such
modifications should be made incrementally with
careful observation of resultant changes in wet weather
flow patterns in the CSS to prevent flooding.
Pump Station Operation and
Maintenance Practices
Routine pump station O&M can also improve the
conveyance of wet weather flows to the WWTP;
this includes regular maintenance of pumps and
accessories, as well as periodic cleaning of wet wells
to remove grit, scum, and debris. Where emergency
generators are provided, generators should be exercised
weekly (NYSDEC 2003). Automatic transfer switches
for transferring power from emergency generators
or backup utility power feeds should be tested and
exercised periodically. To be sure that all equipment
is ready for service when wet weather arrives, regular
maintenance of all equipment should be provided in
accordance with the manufacturer's recommendations.
In addition to routine O&M, more detailed assessment
of pump station performance can be made to ensure
that the maximum flow is delivered to the WWTP.
These include evaluating whether the pumps are
currently able to achieve their rated pumping capacities
and whether improved wet weather operating
procedures would increase the flow volume delivered
to the WWTP. Rehabilitation or replacement should be
considered for pumps that are no longer able to achieve
their rate pumping capacity. Wet weather operating
procedures can include adjustment to pump stations
and their control systems to increase in-system storage
during wet weather. For example, if the inlet sewer to
the pumping station is not normally submerged and
has available storage capacity, pump controls can be
adjusted to allow the wet well level to rise above the
feed pipe elevation, resulting in storage in the sewer
system (NYSDEC 2003).
Sewer System Operation and
Maintenance Practices
Operations and maintenance activities are necessary
for sewer systems to function as designed and to deliver
the maximum flow possible to the WWTP. Over time,
sewer systems can deteriorate structurally or become
clogged through the introduction of oil and grease and
other obstructions into the sewers. Grit buildup reduces
the hydraulic capacity of sewers and interceptors
by reducing the cross-sectional area and increasing
frictional resistance.
O&M practices include pollution prevention, sewer
cleaning, monitoring, testing, inspection, and repair or
rehabilitation. These activities enhance sewer system
performance and are important for maintaining
conveyance capacity. Some states include specific O&M
requirements in NPDES permits for sewer systems in
order to maximize the transport of wet weather flow to
the WWTP for treatment. For additional information
on proper O&M, see the series of O&M Technology
Descriptions in Appendix B of the 2003 Report to
Congress on the Impacts and Control of Combined Sewer
Overflows and Sanitary Sewer Overflows.
Conveyance Capacity Evaluations
Quantifying sewer system transport capacity is
valuable for communities seeking to maximize flow to
their WWTPs. Evaluating transport capacity involves
determining the maximum amount of flow that can
be transported by the primary trunk sewers and
interceptors without raising water elevations in these
sewers to levels which increase the risk of basement or
street flooding (Sherrill et al 1997).
Models, varying from simple to complex, are
commonly applied to rate a sewer system's transport
capacity. Historical information can be used to identify
target water levels within the system that do not cause
problems such as SSOs, basement backups, or street
flooding. Transport capacity is determined through
evaluation of modeled flows at flow rates less than or
equal to the target water levels. Interceptor sewers and
trunk lines are usually rated separately.
CSC-2
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Collection System Controls: Maximizing Flow to Treatment Plant
It is important to consider site-specific characteristics
of the sewer system when evaluating conveyance
capacity. Conveyance of flow through a sewer is
dependent on the difference in water level from the
upstream to the downstream end, pipe slope, sewer size
(length, shape, and cross-sectional area), and roughness
characteristics. Under ideal conditions, a single sewer
pipe may be able to convey flow at its entire capacity.
However, real-system boundary conditions such as
river elevations, downstream sewer capacities, regulator
capacities, and pump station wet well levels will affect
the transport of flow (Sherrill et al. 1997).
The presence of bottlenecks in a sewer system is also
an important consideration in conveyance capacity
evaluations. Bottlenecks may occur at any point in the
sewer system; they limit the amount of flow that can be
transported to the WWTP for treatment during periods
of high flow. Chronic bottlenecks typically occur as a
result of insufficient interceptor capacity that causes
flow to backup in connecting sewers. An example of
a bottleneck resulting from insufficient interceptor
capacity during a wet weather event is presented in
Figure 1. As shown, the hydraulic response to the
bottleneck is a decrease in flow velocity and an increase
in water level. In acute situations, water levels increase
until they rise above an overflow point (in this case the
manhole rim) and an SSO occurs (ASCE 2000). Both
velocity and water level return to normal once the high
wet weather flow rates subside.
Increase in Time
Figure 1. Schematic showing water levels and velocity
conditions at a manhole when a bottleneck
occurs (ASCE 2000).
Bottlenecks may also occur when the sewers delivering
flow to the WWTP have less capacity than the
individual unit processes at the plant. For example, if
interceptors leading to the WWTP have a conveyance
capacity of 50 MGD, yet unit processes (e.g., primary
treatment, secondary treatment, and disinfection) at
the plant can treat 75 MGD, a hydraulic bottleneck
exists in the sewer system. This bottleneck prevents
the treatment capacity of the plant from being fully
utilized. In order to maximize flow to the WWTP,
bottlenecks need to be reduced or removed. Potential
modifications include (Field etal 1994):
• Increasing interceptor, pumping station, and/or
trunk line transport capacity by replacing,
rehabilitating, or adding parallel sewer
components;
• Injecting polymers into the sewer system to reduce
sewer roughness and increase carrying capacity in
surcharged areas; and
• Improving operations and management
procedures to remove obstructions.
Real-Time Control and Monitoring
Monitoring and the use of real-time control
technologies can also assist in maximizing flows to
the WWTP. An effective monitoring program that
gathers information on rainfall, flow, and storage
at major hydraulic control points enhances the
overall understanding of system performance. In
SSSs, enhanced monitoring information can be used
operationally to identify blockages or rainfall induced
SSOs. In CSSs, the linkage of real time flow, regulator,
pump, and storage information can be used effectively
to maximize use of the sewer system for storage and to
maximize flow to the WWTP for treatment. Additional
information on real-time control technologies is
presented in the "Monitoring and Real-Time Control
Technology Description" in Appendix B of the
2003 Report to Congress on the Impacts and Control
of Combined Sewer Overflows and Sanitary Sewer
Overflows.
Key Considerations
Applicability
Maximizing flow to the WWTP requires attention to both
regulatory issues (e.g., NPDES permit requirements) and
technical considerations (i.e., conveyance and treatment
capacity). WWTPs are generally subject to EPAs secondary
treatment regulations. Secondary treatment requirements
specify effluent concentration limits for biochemical
oxygen demand (BOD) and total suspended solids (TSS),
as well as a minimum removal percent (85 percent). These
requirements are enforceable conditions in WWTP permits.
The regulations provide some flexibility for WWTPs in
communities receiving elevated flows (and more dilute
influent) during wet weather by allowing for waivers of the
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Report to Congress on the Impacts and Control ofCSOs and SSOs
percent removal requirement. Waivers are not available,
however, from effluent concentration limits (EPA 1995).
Therefore, the optimal volume of wet weather flow
transported to the plant may be constrained by provisions
in existing discharge permits and the ability to modify
provisions for increased flows during wet weather events.
Understanding the link between sewer system and
WWTP operation can be the difference between effective
treatment of wet weather flows and adverse environmental
and financial consequences. Operational and structural
modifications to maximize flow transport to the WWTP
should only be made if the WWTP can accept the increased
flows. Otherwise, consequences may include flooding
the treatment plant and reducing treatment efficiency at
the plant for extended periods of time. Likewise, changes
in sewer system operation without a careful analysis of
transport capacity could result in an increase in basement
backups or street flooding. For these reasons, both sewer
system and WWTP capacity issues should be evaluated
when implementing this control (see Table 1).
Cost
Maximization of flow to the WWTP can be a very cost-
effective technique for controlling CSOs and SSOs. This
control seeks to optimize use of existing sewer system and
treatment plant capacity, which can lessen the need for
construction of new facilities. The value of maximizing
flow to the WWTP is dependent on the system-specific
availability of underutilized conveyance and treatment
capacity. Although some cost increases can be expected for
WWTP operation, optimizing the use of existing facilities
is likely to be more cost-effective than construction of
structural controls at one or more upstream locations.
Implementation Examples
PHILADELPHIA, PA
Maximizing Conveyance Capacity
Responsible Agency: Philadelphia Water Department
Population Served: 2.1 million
Service Area: Not Available
Sewer System: 1,600 mi. of combined sewer;1,200 mi.
of separate sanitary and storm sewer
The first phase of the Philadelphia Water Department (PWD) CSO
strategy focused on the implementation of the nine minimum
controls (NMC), including increasing the transport of flow to the
WWTP for treatment.To garner information for PWD's NMC program
(and eventually the long term control plan), PWD instituted a
$6.5 million project to upgrade its comprehensive system flow
monitoring network in its three drainage districts. This flow
monitoring program provided information to monitor system performance and enhance operation of the system through existing
infrastructure (PWD 1997).
PWD also took steps to maximize flow to their wastewater treatment facilities in the second phase (capital improvement) of their
CSO program. For example, analysis of the Northeast Drainage District Collector System, which conveys flow from almost half of
the combined sewer area, showed that sewer operation modifications could significantly increase the volume of wet weather
flow transported for treatment. Potential modifications included (1) reduction of hydraulic constraints in the system that limit
the conveyance capacity of the sewers; and (2) modification of large sewers to provide additional wet weather flow storage and
conveyance capacities.
PWD has implemented a range of projects to maximize conveyance to their treatment plants including adding a real-time control
system, replacing pipes and raising dams at regulators,and cleaning and modifying the hydraulic control point regulators along the
main level gravity sewers. A major goal of PWD's LTCP strategy also includes optimizing interceptor sewer system performance by
maximizing the conveyance capacity of existing interceptors. Example projects are provided below.
• Somerset Interceptor Conveyance Improvements: Removal of grit, sediment, and debris from the interceptor enabled the full
hydraulic capacity of the interceptor to be utilized, allowing for increased capture and representing an approximately 10
percent reduction in CSO volume.The project budget was $300,000.
• Cobbs Creek Low Level Control Projects: Grit accumulation reduced the hydraulic capacity in an interceptor that conveys flow
to the low-level pumping station.The grit was removed; flow was also rerouted with a 30-inch pipe, increasing the capacity
from 11.8 MGD tol 5 MGD.This project was completed at a cost of $200,000.
More information athttp://www.phila.gov/water/
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Collection System Controls: Maximizing Flow to Treatment Plant
DETROIT, Ml
Assessing Transport Capacity
Responsible Agency: Detroit Water and
Sewage Department
Population Served: 3 million
Service Area: 921 sq. mi.
Sewer System: 3,000 mi. of sewer
The WWTP for the City of Detroit receives wastewater via three interceptors.The city
conducted an extensive study which rated its sewer system for both conveyance and
storage of combined sewage. Rating the conveyance capacity involved determining
the maximum amount of flow that can be transported by the primary trunk sewers
and interceptors without raising water elevations in these sewers to levels that
increase the risk of basement or street flooding. Historical information was used to
establish these water levels throughout the CSS. In addition, design data at specific locations were used,and detailed risk evaluations
were conducted at specific locations in the system.
System rating included use of the Greater Detroit Regional Sewer System model to simulate flow throughout the sewer system for
a range of storm events.Target water levels determined from the historic information were compared against the resulting water
levels produced by the model. Flow rates, which predicted water levels equal to or less than target water levels, were used to establish
the transport ratings.Trunk sewers and four interceptor sewers were rated separately (Sherrill etal. 1997).
More information athttp://www.wadetrim.com/resources/pub_conf_collmte.pdf
BOSTON, MA
Elimination of Bottlenecks and System Optimization
Responsible Agency: Massachusetts
Water Resources Authority
Population Served: 2.5 million
Service Area: 228sq. mi.
Sewer System: Not Available
Massachusetts Water Resources Authority's (MWRA) CSO plan was developed as part
of an overall master plan that recommended interceptor system projects to eliminate
bottlenecks that contribute to CSOs and to optimize existing facility operation
during wet weather. Between 1988-2000, several transport-related projects were
conducted to maximize wet weather flow conveyance to Deer Island Treatment
Plant.This included rehabilitation of trunk sewers, improved pumping at Deer Island
Treatment Plant, replacement of other pump stations within the collection system,
and construction of a new pumping station.This component of MWRA's CSO program provided reductions in CSO discharge from
approximately 3.3 billion gallons (BG) annually in 1988 to approximately 1.0 BG in 2000 (MWRA 2000).
More recently, MWRA has begun work on the Braintree-Weymouth Relief Facilities Project.This project will expand and improve the
Braintree-Weymouth System, which is MWRA's network of sewer pump stations, interceptors,and siphons that serves six Boston area
communities. Wastewater generated by the six communities currently must pass through the Braintree-Weymouth pump station.
The 54 MGD capacity at this pump station, however, is not sufficient to handle peak flows and presents a hydraulic bottleneck.The
project will increase the Braintree-Weymouth System's peak flow capacity by approximately 19 MGD, streamlining the flow route
from South Shore communities to the Nut Island Headworks and the Deer Island Treatment Plant. Specifically, the project includes
constructing an intermediate pump station and a multi-use deep rock tunnel, replacing and rehabilitating the Braintree pump
station,and adding new interceptors and siphons.The total project cost is estimated at $150 million (MWRA 2001).
More information at http://www.mwra.state.ma.us
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References
American Society of Civil Engineers (ASCE). 2000. Protocols
for Identifying Sanitary Sewer Overflows. Prepared by Black
& Veatch under EPA, Office of Wastewater Management
Cooperative Agreement. EPA Cooperative Agreement #CX
826097-01-0. Reston, VA: ASCE.
EPA Office of Water. 1995. Combined Sewer Overflows-
Guidance for Nine Minimum Controls. EPA 832-B-95-003.
Field, R., et al. 1994. Optimization ofCSO Storage and
Treatment Systems. Presented at "A Global Perspective for
Reducing CSOs: Balancing Technologies, Costs, and Water
Quality" Water Environment Federation (WEF) Specialty
Conference, Louisville, Kentucky. July 10-13, 1994.
Massachusetts Water Resources Authority (MWRA). 2000.
MWRA Business Plan Strategy #17: Implement CSO Control
Plan byFY09 - Draft, v. 1.2. Retrieved September 1, 2003
http://www.mwra.state.ma.us/org/busplan/17.pdf
MWRA. 2001. Facts about the Braintree-Weymouth Relief
Facilities Project. Boston, MA: Massachusetts Water
Resources Authority. Retrieved September 4, 2003
http://www.mwra.state.ma.us/03sewer/graphic/
braintreeweyFSO 1 .pdf
NYSDEC. 2003. Wet Weather Operating Practices for POTWs
with Combined Sewers: "Technology Transfer Document."
Retrieved September 1, 2003
http://www.dec.state.ny.us/website/dow/bwcp/ww_
techtran.pdf
Philadelphia Water Department (PWD). 1997. CSO
Documentation Long Term Control Plan. Submitted to:
Pennsylvania Department of Environment Protection
Bureau of Water Quality Management in partial fulfillment
of NPDES Permit Nos. PA 0026689, 002662, 0026671
(January 27, 1997).
Sherrill, J.D., et al. 1997. Rating and Optimization of
Collection System Transport and Storage. Presented at
Water Environment Federation Technical and Exhibition
Conference in Chicago, IL. October 18-22, 1997.
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
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RIPTION
Collection
ntrols
Monitoring &
Real-Time Control
Overview
Effective monitoring programs enable evaluations of
diurnal and day-to-day flow patterns as well as inflow and
infiltration (I/I) in the system. Such programs also provide
a basis to assess the need for, or effect of, maintenance
efforts. Monitoring has the potential to provide insight
into operational issues and problems, including the
identification of CSO and SSO events, in a timely
manner. Moreover, monitoring is valuable in establishing
maintenance schedules, in developing hydraulic models
for planning related to capital improvements, and for
regulatory compliance.
In sanitary sewer systems (SSSs), enhanced monitoring
information can be used operationally to identify blockages
or capacity constrained areas of the system where wet
weather SSOs may occur. The use of rainfall-derived
infiltration and inflow (RDII) quantification methods can
also serve as a predictive tool to control SSOs. In combined
sewer systems (CSSs), the linkage of real-time flow,
regulator, pump, and storage information can effectively
maximize use of in-system and off-line storage facilities
and maximize flow to the treatment plant. It should be
noted that real-time control can also have substantial value
in some SSSs (e.g., those sized for future growth or I/I).
However, for practical as well as operational purposes,
enhanced monitoring is discussed herein as an SSO control,
and real-time control is discussed as a CSO control.
Enhanced Monitoring
Enhanced monitoring takes routine monitoring of
system conditions a step further by using monitoring
information to track patterns and guide operations and
maintenance (O&M) decisions. Enhanced monitoring
generally consists of a network of rain gages, flow
meters, pump station, and storage measurement
devices that are fully integrated into an information
management system. The components of the
information management system can include:
• Hardware to measure system conditions (i.e.,
rainfall, sewer flow, pumping rate, storage level,
etc.);
• Software, a central processor, and work stations
to house management programs and to track,
analyze, and display system information;
• Reporting mechanisms for compliance purposes;
and
• Established procedures to respond to problems as
they are identified.
In practice, enhanced monitoring is typically applied
systemwide as an SSO control. Abnormal wastewater
flow patterns indicative of a blockage, pump station
failure, or excessive I/I can be detected automatically.
In sewer systems with enhanced monitoring programs
(e.g., flow monitoring alarm systems), problematic
conditions and blockages may be identified in advance
so that prompt attention and repair may prevent SSOs
from occurring. In cases where SSOs have already
occurred due to blockage or power failure, early remote
detection by an enhanced monitoring network can
lead to a prompt response that minimizes the volume
and duration of the overflow as well as any potential
environmental and human health impacts. Enhanced
monitoring can be an economical way to identify
and track SSO events that were previously largely
unpredictable.
RDII Quantification
During dry weather, flow in SSSs primarily consists of
domestic, commercial, and industrial wastewater mixed
with some groundwater infiltration. During periods of
rainfall and snowmelt, however, dramatic increases in
wastewater flows are often noted and can contribute
to SSOs and increased treatment costs. The portion
of sewer flow above normal dry weather flow is called
RDII. Most communities served by SSSs are challenged
to find effective means for predicting sewer system
response to wet weather events; enhanced monitoring
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Report to Congress on the Impacts and Control ofCSOs and SSOs
programs often exceed their financial and staffing
capabilities (WERF 1999).
RDII quantification methods are a tool for estimating
the magnitude (frequency, location, and volume) of
RDII and can inform efforts to improve sewer system
performance. RDII quantification often precedes the
development of enhanced monitoring programs
The Water Environment Research Federation (WERF)
recently funded an extensive study that identified eight
RDII hydrograph generation or RDII quantification
categories (WERF 1999):
• Constant unit rate methods
• Percentage of rainfall volume (R-value) methods
• Percentage of streamfiow methods
• Synthetic unit hydrograph methods
• Probalistic methods (frequency analysis of peak
RDII)
• Predictive equations based on rainfall/flow
regression
• Predictive equations based on synthetic streamfiow
and basin characteristics
• RDII as a component of hydraulic software
These methods were tested under varying climatic and
sewer operation conditions. With the goal of improved
prediction and control of SSOs, the study found that
no single RDII quantification method was universally
applicable. Availability of data and experience of the
research team were among the factors that influenced
the usefulness of each method (WERF 1999).
A hydraulic (routing) analysis, which models the
existing sewer system's ability to transport RDII, is
recommended with RDII quantification to determine
where SSOs will likely occur in the system. Once
problems are characterized, RDII methods may also
be used to evaluate and size appropriate control
technologies and capacity relief scenarios. Because the
same storms (including the same antecedent conditions
and rainfall distributions) are unlikely to occur before
and after controls are implemented, sewer system
evaluations must rely on RDII quantifications (WERF
1999).
Real-Time Control
Real-time control seeks to optimize sewer system
performance during wet weather events as flow
and storage conditions change within the system.
Many of the same information management system
components described as part of enhanced monitoring
are also required for real-time control. Real-time
control is typically most applicable in CSSs, as these
systems tend to have substantial in-system storage in
large pipes designed to transport excess wet weather
flows. In addition to large pipes, CSSs may also have
additional storage space (e.g., tunnels and tanks)
that can be incorporated into a real-time control
strategy. Maximizing system performance may lead to
substantial savings in capital improvement programs
if evaluated during the development of a long-term
control plan (LTCP) (Field et al. 2000). Using feedback
loops and rules to optimize storage, pumping, and
treatment, real-time control technologies are capable of
reducing the frequency, duration, and volume of CSOs
through optimization of sewer system operations.
CSSs that use real-time control technology have system
regulator elements such as weirs, gates, dams, valves, or
pumps that can function in a real-time environment.
Real-time control systems rely on monitoring data and
use a customized software program to operate regulator
elements without a significant time delay. Figure 1
shows a monitoring network used to operate a real-
time control system.
Figure 1. Schematic of a monitoring network.
The regulator elements function according to operating
rules that are generally based on flow level, storage, or
pumping rates monitored at points within the CSS. In a
simple example, a regulator element can be controlled
locally based on conditions that are monitored within
the vicinity of that element. Alternatively, in a more
complex example, global control of regulator elements
would rely on a centralized control device that analyzes
system-wide monitoring data. Centralized control
systems can rely on either human operators or fully
automated computer controls. Real-time control
regulators that operate based on monitoring inputs are
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Collection System Controls: Monitoring & Real-Time Control
referred to as reactive systems. Predictive systems, in
contrast, include additional forecast data in the control
process. Some predictive real-time control systems
include a sewer system model as a component of the
control device. In some instances, rainfall forecasts have
been used successfully to optimize system operations in
anticipation of rainfall.
Key Considerations
Applicability
The use of enhanced monitoring and real-time control
is consistent with the goals and objectives of many O&M
programs and EPA's 1994 CSO Control Policy. Enhanced
monitoring and real-time control can be used to ensure
that the public receives adequate notification of CSO and
SSO events and potential impacts. Further, use of real-time
control technologies for CSO control addresses two of the
nine minimum controls (NMC). These are: maximizing
use of the sewer system for storage; and maximizing
flow to the wastewater treatment plant. In comparison,
RDII quantification methods have lesser information
requirements than enhanced monitoring techniques. RDII
hydrograph generation methods can be used to predict
RDII in different portions of an SSS and to evaluate source
control scenarios, and in some cases, to develop enhanced
monitoring programs.
Enhanced Monitoring
Sewer system monitoring is an essential component
of an O&M program in most systems. An enhanced
monitoring network utilizes fact-based knowledge
to optimize sewer system performance. Enhanced
monitoring can be used to determine the magnitude
of the I/I and to better define locations where it is
occurring. It can also provide direction for maintenance
activities, detection of illicit storm water connections to
the SSS, and in some cases, the detection of SSO events.
The size and complexity of the monitoring network
usually depend on the size and complexity of the
sewer system as well as financial considerations. In
general, automated monitoring technologies are more
applicable in larger systems, while simpler monitoring
devices are better suited to smaller systems. In either
case, the use of enhanced monitoring techniques
can lead to better decisions on capital improvements
required for wet weather control facilities.
Many municipalities have supervisory control and
data acquisition (SCADA) systems already in place,
which can be operated in an enhanced monitoring
role if they are linked to broader information
technology management systems. The information
collected by existing SCADA systems is often used
locally rather than globally. Sharing relevant SCADA
system information among many linked facilities as
part of an information management system makes
the information more meaningful; it also presents
opportunities for detection of SSOs that would not
otherwise exist.
RDII Quantification
Many communities do not have the resources necessary
to implement enhanced monitoring programs.
However, over-reliance on limited data and/or the
rough interpretation of monitored flows can lead to
oversimplification of RDII causes and implementation
of inadequate control technologies. Selection of an
appropriate technique for estimating RDII is critical.
Usefulness of a given RDII quantification method
depends on availability of data, experience of the
analysis team, and purpose of the RDII evaluation
(e.g., source control evaluation). Further, regardless of
the RDII method selected, WERF (1999) found that
testing on multiple storms is necessary to evaluate the
true potential of the RDII quantification method for
extrapolation or comparison with other wet weather
events. Table 1 presents a number of factors that may
confound the interpretation of monitoring data in SSSs.
Real-time Control
Real-time control, in general, works best for CSO
communities with populations greater than 50,000.
Local, rather than centralized, real-time control systems
may be cost-effective for smaller CSO communities
with limited control points. Real-time control tends
to be more effective in areas with level, as opposed
to steep, terrain where it is more practical to store
wastewater in existing sewers. Further, a CSS that is
already operating at or near capacity will not benefit
from real-time control; systems which have capacity
that is not being used effectively stand to gain more.
Real-time control has also proved useful for
communities with both sanitary and combined sewers
(e.g., Milwaukee, WI; Louisville, KY; and Quebec,
Ontario, Canada). In such systems, real-time control
is used to divert flows to and from storage systems
during wet weather. For example, real-time control is
used to prevent storage systems from filling entirely
with combined sewage, reserving space for separate
sewage. This is achieved by incorporating separate
sewer volume predictions into the real-time operational
strategies, where the goal is eliminating SSOs and
minimizing CSOs (Schultz et al 2001).
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 1 .Common interpretations of flow monitoring data (WERF 1999).
Monitoring Data Observation Common Interpretation Confounding Factors
Dry weather flow consistently
higher than expected sanitary
flow contribution
Infiltration through leaky
pipes
• Leakage from an adjacent lake or river directly into sanitary
sewer
• Underground spring intercepted by the sanitary sewer
• Seasonal fluctuation in groundwater
Rapid,dramatic rise in flow
coincides with rainfall initiation
Unauthorized direct
connection of roof or yard
drains
• Leaking manhole lids or corbels in depressions that collect
runoff
• Leaky pipes along stream banks
• Cross-connection with storm water systems
• Interconnection of the sanitary sewer with underground
solution channels (common in karst topography)
Delayed and prolonged flow rise
occurs after rain
Unauthorized connection of
sump pumps or foundation
drains to sanitary sewer
• Granular backfill in the sanitary sewer trench acting as a french
drain
• Seasonal fluctuation in groundwater; response may be rapid
depending on soils and trenches
Flows rise proportionately
to rainfall, but only up to an
observable maximum
Direct connections with
capacity restrictions
• Further flow increases restricted by downstream blockages,
backwater, or lift station capacity
• Further flow increases relieved by upstream overflows
Some advantages of real-time control include:
• Storage facilities can be dynamically operated and
continuously optimized in response to changing
conditions;
• Runoff and hydraulic models can be integrated
into operating rules and control algorithms;
• System response can be predicted through use of
rainfall forecast data and a local rain gage network
with adequate spatial coverage; and
• Seasonal and spatial variation in rainfall and
receiving water flows and volumes can be
accounted for in the system.
Communities that do not experience much spatial
or seasonal rainfall variation or that utilize receiving
waters with a static assimilative capacity may not be
able to take advantage of some these real-time control
features.
Cost
The capital cost of implementing an enhanced monitoring
or real-time control scheme depends on the quality and
quantity of control, the measurement devices required
for successful implementation, as well as any software
needed to manage or process the data (Field et al 2000).
Monitoring and control schemes may not be sufficient as a
stand-alone solution to completely control CSOs or SSOs;
therefore, they should be evaluated as part of the solution.
O&M costs are dependent on the characteristics of the
system being monitored and include regular inspection
of the monitors. In systems using real-time control, O&M
costs also include mechanical maintenance of the regulator
elements.
The initial costs of enhanced monitoring or real-time
control can be significant and may be prohibitive for small
communities. The monitoring costs, however, may be a
fraction of the cost of large capital projects that would
achieve similar levels of CSO and SSO reduction, such
as construction of additional conveyance, storage, or
treatment facilities.
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Collection System Controls: Monitoring & Real-Time Control
Implementation Examples
SEATTLE, WA
Reol-Time Sewer System Controls
Responsible Agency: Seattle Public Utilities
Population Served: 1.4 million
Service Area: 64 sq. mi.
Sewer System: 335 mi. sewer
Seattle was one of the first U.S. communities to implement and operate
an advanced real-time control system. Seattle's system, called Computer
Augmented Treatment and Disposal (CATAD), began operating in 1971.CATAD
manages 13,120 acres of fully combined sewer area as well as 28,000 acres of
partially-separated sewers.The network included 17 regulator structures and
one major pumping station. CATAD has reduced CSO volume between 9 and
49 percent at different outfall locations. The actual reduction realized depends on the rainfall volume and patterns during each
individual year.
The capital cost for CATAD was $16.8 million, and O&M costs were approximately $16 per acre (2002 dollars). Estimated costs for
sewer separation or construction of additional storage capacity to achieve equivalent reductions in overflow volume range between
$127-$760 million (2002 dollars). In the late 1980s, treatment plant computer hardware was upgraded, remote telemetry units at
regulators and pump stations were replaced by programmable logic controllers, and operators'graphical displays were improved.
Based on the success of the CATAD technology, Seattle implemented a new, predictive real-time control system that went online
in early 1992. Rainfall prediction capabilities that utilized rain gage data and a runoff model were added at this time. A global
optimization program was introduced that computed optimal flow and corresponding gate position for each regulator. Currently,
the system's centralized computer hardware is being upgraded.
Contact: Bob Swarmer, King County Wastewater Treatment Division
MILWAUKEE,WI
Real-Time Sewer Sytem Controls
Responsible Agency: Milwaukee
Metropolitan Sewerage District
Population Served: 1.1 million
Service Area: 420 sq. mi.
Sewer System: 2,200 mi. of collector sewer;
310 mi. of intercepting and main sewer
In 1986, Milwaukee Metropolitan Sewerage District (MMSD) designed and
installed real-time sewer system controls.The MMSD sewer system includes
the Metropolitan Interceptor Sewer System (MIS) that collects flow from the
local sewers; an Inline Storage System (ISS) that temporarily stores excess
flows until treatment capacity is available, and a computer-based central
control system.The MIS system collects wastewater from both sanitary and
combined sewers and conveys flow to two wastewater treatment plants.
MMSD uses remote and local sensors to control intra-system flow diversions to both relief interceptors and temporary storage.
Flows can be rerouted to avoid surcharging the system or to maximize treatment capacity during wet weather events. Routing is
performed by adjusting diversion gates, which are controlled by monitoring multi-level sensors located at critical points in the MIS.
Importantly, MMSD's real-time control system is used to prevent storage systems from filling entirely with combined sewage and to
reserve space for the separate sanitary sewage.This is achieved by incorporating sanitary sewer volume predictions into the real-
time operational strategies, where the goal is eliminating SSOs and minimizing CSOs. Precipitation and meteorological forecasts are
used to calculate the storage volume that must be reserved for anticipated sanitary sewage flows.
MMSD's system was implemented to address chronic CSO and SSO problems cited in national and state court actions in the 1970s.
In the mid-1970s, the city regularly experienced hundreds of SSOs and over 100 CSOs during wet weather; many homes in the
sanitary sewer service area also faced sewage backups one or more times per year. MMSD has seen dramatic reductions in CSOs,
SSOs,and backups in the last few decades. Furthermore,the real-time control system has provided much-needed flexibility in system
operation,allowing MMSD to better accommodate variable precipitation patterns,growth patterns,and lake and groundwater levels
(Schultz eta/. 2001).
Contact: Nancy Schultz, CH2M Hill
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Report to Congress on the Impacts and Control ofCSOs and SSOs
QUEBEC, ONTARIO,
CANADA
'
Reol-Time Control System
Responsible Agency: Quebec Urban Community
Population Served: 500,000
Service Area: 213 sq. mi.
Sewer System: Not Available
In 1998-1999, the City of Quebec implemented a centralized, or
global, optimal and predictive real-time control (GO RTC) system
in its westerly sewer system. Quebec Urban Community's (QUC's)
westerly catchment drains 82,000 acres and contains 41 miles of
interceptor and 22 regulators; it is served by an 82 MGD treatment
plant.The GO RTC equipment consists of five control stations, four
monitoring stations,thirteen rainfall stations,and one central control station (Colas etal. 2001).The GO RTC system improves the flow
management of the westerly system by taking advantage of 3.7 million gallons of in-line storage as well as wet weather treatment
capacity at the plant. Pressure flow conditions that occur in the system are also eliminated, thereby protecting downstream areas
against basement backups.The cost of the western installation GO RTC system was approximately $2 million. Operation costs are low
because existing staff were trained to operate and maintain the system (Colas 2003).
In the late 1990s, EPA funded a demonstration study of three real-time control scenarios in the westerly QUC catchment (Field etal.
2000). Using modeling tools and rainfall data from the summer of 1998, Field etal. (2000) found that the automated central control
system, eventually implemented as GO RTC, performed better as system complexity increased. Actual reductions in CSO volume
have exceeded those predicted by Field et a/.(2000)-i.e., reductions of 24-47 percent. Compared to simulations of past system
configurations, CSO volumes were reduced by 60 percent in 1999,75 percent in 2000,and 83 percent in 2001. At some sites, CSOs
were eliminated. In other areas, where storage was limited, CSO frequency was reduced by more than 40 percent (Colas 2003).
Contact: H. Colas, BPR CSO
SAN DIEGO, CA
Flow Metering Alarm System
Responsible Agency: City of San Diego
Metropolitan Wastewater Department
Population Served: 1.3 million
Service Area: 310 sq. mi.
Sewer System: 2,300 mi. sewer
The City of San Diego MWWD installed a Flow Metering Alarm System
(FMAS) in September 2000. FMAS uses flow meters to monitor wastewater
flow conditions, which provides real-time event notification through the
land-line telemetry system. Specifically, 92 alarmed flow meters provide
coverage for 95 percent of MWWD's sewers with a diameter of 15 inches or
greater. Flow meters are also used by MWWD to meter flows from San Diego
and its 15 satellite agencies,collect data for sewer modeling, evaluate trunk
sewer capacities, and investigate I/I issues. MWWD hired a maintenance contractor to maintain all the flow meters in their system
including those used for FMAS. In addition, MWWD created a new section of three to four staff (with supplemental help on nights
and weekends) to monitor the sewer system,analyze data,and dispatch crews to investigate potential spills and/or minimize active
SSOs.
The purpose of FMAS is to help prevent, detect, and minimize the impact of major SSOs in the MWWD system. An alarm signals
when a FMAS meter experiences a 25 percent loss of flow. For some areas where the base flow is more consistent, the alarms can be
set to activate when a 15 percent fluctuation in flow occurs. MWWD installed FMAS largely as a result of a large spill that occurred
in February 2000 when the Alvarado Trunk Sewer was damaged during a winter storm, causing a 34 million gallon spill in an
inaccessible canyon that went undetected for seven days.This spill forced beach closures,a highly undesirable situation for the City
of San Diego and surrounding communities.
The FMAS has allowed MWWD to concentrate on specific areas of the SSS: trunk sewers where capacity is critical, remote areas, and
sensitive areas including areas that would trigger beach closures. Although FMAS is principally used to detect major SSOs, it has also
provided early warning of potential spills allowing crews to be dispatched in time to alleviate blockages. Over the past three years,
MWWD has also considerably expanded its maintenance and cleaning program and is embarking on a 10-year capita I improvement
program to replace or rehabilitate structurally defective pipe,all in an effort to reduce future SSOs.
Contact: G. Hwang, City of:San Diego Metropolitan Wastewater Division
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Collection System Controls: Monitoring & Real-Time Control
ATLANTA, GA
Automated Monitoring System
Responsible Agency: Atlanta Department
of Public Works
Population Served: 1.2 million
Service Area: 131.4 sq.mi.
Sewer System: 2,000 mi. of sanitary and
combinedsewer
In 2002, Atlanta installed a web-based information system that automates
data collection from flow meters and rain gages. One hundred twenty flow
meters and 35 rain gages provide coverage of the city's entire sewer system
and supply data to the information system. This system enables city staff
to view pipe capacities, flow levels, and float positions (in the pumping
stations) via the Internet. Alarms calibrated to the system activate when
flow velocities or depths reach predefined critical levels, where the potential
forSSO events is high.
Flow meters and rain gages have been used in the Atlanta sewer system for a number of years. In the past, field crews were required
to collect the data,and it often took many weeks for the data to be analyzed. Without alarms or real-time data, the city was frequently
faced with responding to spills after they had been reported by the public or detected by field crews. By automating data collection,
the city is better able to analyze the data in a timely manner. Crews may be sent to investigate potential problems and act to prevent
SSOs rather than respond to an overflow event.
In addition, the system has helped the city better allocate its resources and focus on sewer lines that need repair,areas where flow
capacity is frequently exceeded,and sections where recurrent blockages occur. If grease build-up is identified as a chronic problem
in a certain section of pipe, the crew that handles oil and grease issues will be dispatched to investigate (e.g., check grease traps).
The city reports that businesses, such as restaurants, a re more receptive to preventative operation and maintenance changes when
shown evidence (provided by the monitoring data and CCTV) of the recurrent problem.
Contact: K. Toomer, Atlanta Department of Public Works
References
Colas, H., et al 2001. Operation and Performance of an
Optimized Real time Control System for Wet Weather
Pollution Control, Vulnerability of Water Quality in
Intensively Developing Watersheds, Making the Case for
High-Performance Integrated Control. Presented at the
University of Georgia, Athens, Georgia, May 14-16, 2001.
Colas, H. BPR CSO. E-mail correspondence with Limno-
Tech, Inc., 2003. Washington, DC.
Field, R., Villenueve, E., Stinson, M.K. 2000. "Get Real!"
Water Environment & Technology. Vol. 12, No. 4: 64-67.
Hwang, G., City of San Diego Metropolitan Wastewater
Division (MWWD). Interview by Limno-Tech, Inc.,
February 2003. Washington, DC.
Schultz, N., et al. 2001. Milwaukee's Experience in
Collection System Controls. Proceedings of WEF Speciality
Conference, A Collection System Odyssey, Bellevue,
Washington, July 2001.
Schultz, Nancy, CH2M Hill. E-mail correspondence with
Limno-Tech, Inc., 2003. Washington, DC.
Stevens, Pat, ADS Environmental Services. Interview by
Limno-Tech, Inc., January 2003. Washington, DC.
Swarmer, Bob, King County, WA Wastewater Treatment
Division. Interview by Limno-Tech, Inc., December 2002.
Washington, DC.
Toomer, K., Atlanta Department of Public Works. Interview
by Limno-Tech, Inc., February 2003. Washington, DC.
Water Environment Research Foundation. 1999. UsingFlow
Prediction Technologies to Control Sanitary Sewer Overflows.
Prepared by D. Bennett, et al Project 97-CTS-8. Alexandria,
VA: Water Environment Research Foundation.
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
CSC-13
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RIPTION
Inflow Reduction
Overview
Inflow is the direct introduction of storm water into
a sewer system; common sources include roof leaders,
basement sump pumps, area drains in yards and driveways,
foundation drains, cracked or broken manhole covers,
and cross connections with a separate storm water system.
Inflow occurs by design, through disrepair, and via illicit
connections. Inflow reduction refers to techniques used to
reduce the amount of storm water that enters a combined
sewer system (CSS) or a sanitary sewer system (SSS).
This technology description focuses on inflow associated
with direct connections of storm water sources to the
sewer system. Much of the inflow to CSSs is intentional as
these systems were designed to convey excess storm water
away from dwellings and to reduce localized flooding.
Inflow to SSSs is generally not by design and is often
illicit. By reducing the volume of storm water entering
a sewer system, inflow controls free conveyance capacity
and available storage. This, in turn, aides in reducing the
frequency, volume, and duration of wet weather CSO and
SSO events. Inflow reduction is particularly applicable in
areas where open land is available to receive redirected
storm water for infiltration or detention, or where storm
water can be diverted to surface waters either directly or via
a separate storm water system.
Specific inflow reduction techniques that will be discussed
in this technology description include disconnection
of roof leaders; redirection of area drains, foundation
drains, and basement sump pumps; and cross connection
elimination.
Disconnection of Roof Leaders
Roof leaders or down-spouts convey rain that falls on
residential and commercial roofs directly to the sewer
system. The use of this practice in CSSs is usually
intentional, and in some instances, required by local
ordinance. Use of roof leaders to convey rainwater to an
SSS is generally considered to be an illicit connection
in most, but not all, communities. In SSS areas,
roof leaders may have been connected to the SSS by
builders or homeowners to alleviate localized flooding
associated with wet weather events. The disconnection
of roof leaders from the sewer system and redirection
to lawns, dry wells, or drain fields, where flows can
infiltrate into the soil, reduces the amount of storm
water entering the sewer system. Disconnection of
roof leaders works best in residential areas where open
land is available. City-wide surveys are often necessary
to determine the extent of roof leader connections to
the sewer system. This inflow reduction technique can
be introduced as a voluntary effort or as a mandatory
requirement. Guidance can be offered to individual
homeowners on how to redirect the inflow from
roof leaders, and it can be combined with other
inflow reduction techniques such as area drain and
basement sump pump redirection. Some communities
have offered financial incentives to homeowners to
disconnect roof leaders and have prequalified local
contractors to provide this service.
Redirection of Area and Foundation Drains and
Basement Sump Pumps
Many buildings have a system of area and foundation
drains and basement sump pumps to alleviate drainage
problems. As with roof leaders, area and foundation
drains and basement sumps are typically connected
to CSSs by design. In some parts of the country, both
area drains and foundation drains are connected
to the SSS by design, but in most instances they are
considered to be illicit connections to the SSS. Flows
from area and foundation drains and basement sumps
can generally be redirected away from the sewer system
to lawns, dry wells, drain fields, or an existing separate
storm water system. However, redirection may require
additional pumping. City-wide surveys often need to
be conducted to determine where area drains and sump
pumps are located, whether they discharge directly to
the sewer system, and whether it is feasible to redirect
them.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Elimination of Cross Connections
Cross connections are direct connections between an
SSS and a separate storm water system. By definition,
it is not possible to have a cross connection in a CSS.
Cross connections most commonly occur where the
sanitary service lateral from a home or commercial
establishment is inappropriately connected to the
storm water system. Cross connections also often exist
as remnants of incomplete sewer separation projects.
Detection and elimination of cross connections
between separate sanitary and storm water systems can
reduce inflow during wet weather events and reduce
the concentration of bacteria, nutrients, and oxygen
demanding substances contained in storm water
discharges.
Key Considerations
Applicability
There are a number of different sewer testing and
inspection approaches that are useful for locating sources
of inflow. These include visual inspections, smoke testing,
dye-water flooding, water sampling from manholes,
interpretation of public complaints, and video inspection.
The most appropriate technique will depend on suspected
inflow sources and site-specific conditions. Additional
information on techniques for locating sources of inflow
is provided in the "Testing and Inspection Technology
Description" in Appendix B of the Report to Congress on the
Impacts and Control ofCSOs and SSOs.
Inflow reduction can be an efficient way to reduce the
volume of storm water delivered to both CSSs and SSSs,
and can result in improved sewer system performance.
Provided below are specific considerations for each of the
inflow reduction techniques described above.
Disconnection of Roof Leaders
Disconnection of roof leaders is a relatively simple
and low-cost technique for reducing inflow. It is more
feasible in residential areas where houses are detached,
yards are sufficiently large to accommodate increased
overland flow and soils have relatively high infiltration
rates. In order for a roof leader disconnection
program to be successful the public must be educated
about the benefits of disconnection and methods
for implementing the program. This can be time-
consuming and will most likely require some type of
rebate program or other incentive for compliance.
Communities who have experimented with voluntary
disconnection programs found that approximately 20
percent of property owners are willing to participate
(NBC 2000). In addition, because the effect per
individual roof leader is small, this program must be
implemented with broad participation across entire
neighborhoods in order for there to be a discernible
reduction in sewer system flow.
Redirection of Area and Foundation Drains and
Basement Sump Pumps
In general, area and foundation drains and sump
pumps are a less common source of inflow than roof
leaders, and their location may be harder to determine.
The feasibility of redirecting drains and sump pumps
depends on soil type, land slope, and the drainage
conditions around the home or building. If a separate
storm water system does not exist, then the excess
rainwater must be conveyed to a distance far enough
away and at a reverse slope from the building so that
water is not allowed to migrate back into the building.
Similar to the redirection of roof leaders, the volume
controlled per individual drain or sump pump is small.
Consequently, the program must be implemented with
broad participation across neighborhoods in order for
there to be a discernible reduction in sewer system flow.
Implementation of this type of redirection program can
be time-consuming and may necessitate use of a rebate
program or other incentives for compliance.
Elimination of Cross Connections
Several methods exist for detecting and eliminating
cross connections. Common sewer testing and
inspection approaches are often appropriate
for identifying storm water sources that were
inappropriately connected to the SSS. In addition,
there are a number of useful indicators for detecting
connections between private building service laterals
and the separate storm water system. These include
inspections to determine the presence of unexpected
dry weather flow in storm sewer lines, and finding
biological indicators that denote the presence of
human fecal matter in storm drain outfalls. Once cross
connections are detected, excavation and correction are
necessary. In addition to detection and elimination of
existing cross connections, plans for new development
should be carefully reviewed and inspections should
be conducted during construction in order to prevent
future cross connections from being placed.
Cost
The actual cost associated with implementation of an
inflow reduction program varies considerably and is
dependent on site-specific conditions. Disconnection of
roof leaders and redirection of basement sump pumps
can be quite economical under some circumstances.
Disconnecting area and foundation drains typically requires
CSC-16
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Collection System Controls: Inflow Reduction
excavation around homes, and is therefore more expensive
and disruptive than other inflow controls. Key parameters
in determining the effectiveness of inflow reduction
techniques are the infiltration rate of the soil in the area
where flows will be redirected and the land area available
to infiltrate the wet weather flow. Typical cost ranges for
various techniques discussed in this technology description
are presented in Table 1.
Table 1. Costs of inflow reduciton activities
Technology
Disconnection of roof
leaders
$45-$75 for individual
homeowners
Redirection of area and
foundation drains and
basement sump pumps
Varies based on site-specific
requirements.
Sump pump redirection costs
$300-$500 per home"
Cross connection
elimination
Varies depending on location.
Typical point repairs costs $600-
$8,500 b
1 EPA 1999
' Arbour and Kerri 1998
Implementation Examples
JOHNSON COUNTY, KS
Inflow Reduction Prog mm
Responsible Agency: Johnson County Wastewater (JCW)
Population Served: 500,000 Wet weather SSOs were a frequent occurrence in Johnson
Service Area-20 sq mi County in the early 1980s. A comprehensive system-wide
Sewer System: 1,700 mi. of sanitary sewer evaluation was conducted in 1983 which included smoke and
dye-water testing of sewer lines,flow and rainfall monitoring,
visual pipe inspections, and closed circuit television
inspections. The survey identified inflow as a major contributor to wet weather SSOs. JCW's response was to launch an inflow
reduction and sewer system rehabilitation program. An ordinance was passed by the Johnson County Board of Commissioners that
made it illegal for residents to make connections from surface or groundwater sources to the SSS.This ordinance provided JCW with
the legal authority to require removal of unpermitted inflow sources,and to prohibit construction of new ones.
As part of the disconnection program, JCW initiated private property inspections to
identify inflow sources and advise property owners on removal actions. Inspectors
toured commercial and residential building interiors and grounds,and they gathered
data on the location of foundation and area drains, roof leaders, and other apparent
connections to the SSS. Sources suspected of contributing to storm water inflow
were subjected to smoke and/or dye-water testing, and all unpermitted sources
were scheduled for disconnection. As shown on the right, the most common sources
of inflow were foundation drains, area drains, sump pumps, and roof leaders. JCW
established informal fixed-price contracts with local contractors to complete the
work.To help JCW prioritize its remedial efforts,a hydraulic model was developed with
the data from the survey.The inflow reduction program was completed in 1994. The
inflow reduction and sewer rehabilitation program resulted in significant reductions
in capacity-related SSOs; wet weather flow rates in the sewer system were reduced by
an average of 280 MGD during the 10-year, 6-hour storm.The total cost of the program
was $48.8 million, which includes $11.2 million for the reduction of inflow from private
property.
Foundation
Drains
Area
Drains
Sump
Pumps
Roof
Leaders
Types and distribution of inflow
More information at http://cfpub2.epa.gov/dearinghouse/preview.cfm?RESOURCE_ID=253743
CSC-17
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Report to Congress on the Impacts and Control ofCSOs and SSOs
ROCKFORD, IL
Sewer System Evaluation Survey
Number of identified inflow sources."
Responsible Agency: The Rock River Water
Reclamation District The Rock RiverWater Reclamation District in Rockford conducted a survey of a
Population Served: 250,000 portion of its service area that was experiencing SSOs during periods of heavy
Service Area- 80 sq mi rainfall. The purpose of the survey was to determine the extent of inflow and
Sewer System: 1,100 mi. of sanitary sewer to recommend
a plan for
mitigation
that included a
cost-effectiveness analysis to justify the recommended work.
Inflow sources were identified by smoke testing all sanitary sewers
(approximately 77,000 linear feet) by dye-water testing storm
systems adjacent to sanitary sewers, and with voluntary inspections
of approximately 1,300 buildings for sources on private property.
Infiltration and inflow (I/I) data were collected and analyzed in terms
Number of
Area .
Defective Sites
Cherry Valley
Dawson Avenue
Pepper Drive
7
26
35
Inflow
(Gallons Per
Minute)
38.0
167.6
147.8
of location, pipe condition, flow rate, potential rehabilitation method, and cost. The relative cost-effectiveness calculations, using
ratios of rehabilitation costs versus treatment-transport costs, provided the basis for rehabilitation recommendations.The primary
sources of inflow identified were roof leaders, foundation drains, and sump pumps.This investigation identified 68 inflow sources
that contributed an estimated 421 gallons per minute, based on a 5-year storm event (1.7 inches per hour).The investigation also
determined that 75 percent of the I/I originated on private property.
More information athttp://www.rrwrd.dst.il.us/
SOUTH PORTLAND, ME
Rebate Program to Reduce Inflow
Responsible Agency: City of South Portland
Population Served: 23,200
Service Area: 12 sq. mi.
Sewer System: 16.6 mi. of combined sewer
The City of South Portland invested almost $2.5 million
between 1986 and 1995 to reduce wet weather inflow into
their CSS.The program involved surveying 6,000 residential
buildings. The survey identified approximately 380 roof
leaders and 300 sump pumps that were connected to
the CSS. Property owners were notified and offered the
following incentives to disconnect the inflow sources: $75 for roof leader redirection and $400 for sump pump redirection. At the
program's completion in 1995,64.5 percent of all known sources had been redirected.The program resulted in a reduction in CSO
volume of 58 MG per year, a three percent reduction in annual flow to the local wastewater treatment plant, and fewer reported
residential backups. The total cost of the rebate program was $128,000. The inflow reduction program eliminated more than 420
gallons per year of storm water from the CSS for every dollar spent.
Contact: Dave Pineo, Engineering Department, City ofSouth Portland
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Collection System Controls: Inflow Reduction
References
Arbour, Rick, and Ken Kerri. 1998. Collection Systems:
Methods for Evaluating and Improving Performance.
Prepared for EPA, Office of Water Programs, Municipal
Permits and Operations Division and developed under EPA
Grant No. CX924908-01-0. Sacramento, CA: California
State University, Sacramento Foundation.
EPA Office of Water. September 1999. Combined Sewer
Overflow Technology Fact Sheet: Inflow Reduction. EPA-F-99-
035.
Narragansett Bay Commission (NBC). April 2000.
Stormwater Attenuation Study - Technical Memorandum
No. 3, Evaluation of Alternatives. Prepared by the Maguire
Group Inc. Rhode Island: NBC.
Water Environment Federation (WEF). 1999. Control of
Infiltration and Inflow in Private Building Connections.
Alexandria, VA: WEF.
Inclusion of this technology description in this Reportto
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
CSC-19
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RIPTION
Sewer Separation
Overview
Sewer separation is the practice of separating the single
pipe system of a combined sewer system (CSS) into
separate systems for sanitary and storm water flows. Sewer
separation, like other types of CSO control, is intended to
reduce CSO volume, the number of CSO outfalls, or both.
In practice, there are three distinct approaches to sewer
separation:
• Full separation wherein new sanitary sewer lines are
constructed with the existing CSS becoming a storm
sewer system. This is probably the most widely used
form of separation.
• Full separation wherein an entirely new storm sewer
system is constructed with the existing CSS remaining
as a sanitary sewer system. This form of separation is
not often used because the capacity of the existing CSS
was designed to accommodate storm runoff, which is
more than what is required to accommodate sanitary
flows.
• Partial separation wherein a new storm sewer system
is constructed for street drainage, but roof leaders
and basement sump pumps remain connected to the
existing CSS allowing flow to enter the CSS during wet
weather periods.
Full separation can be applied on a system-wide basis to
eliminate the CSS. This approach is often practical only for
communities with small areas served by combined sewers.
Partial separation of select areas within the CSS is widely
used in large and small CSO communities. In fact, a survey
of readily available information in NPDES files indicates
that sewer separation is the most widely used CSO control
(EPA 2001). This suggests that most CSO communities
opportunistically find portions of their CSS where
separation is a cost-effective CSO control. Under these
circumstances, separation is often implemented in
conjunction with other public works projects, including
road work and redevelopment.
Key Considerations
Sewer separation can be highly effective in controlling
the discharge of untreated sewage to water bodies. Under
ideal circumstances, full separation can eliminate CSO
discharges. However, sewer separation on its own does not
always lead to an overall reduction in pollutant loads or
the attainment of water quality standards. Discharges of
urban runoff from the newly separate storm sewer system
often contain substantial pollutant loads that contribute to
water quality problems. A comparison of average pollutant
concentrations from a variety of sources is presented in
Table 1. As shown, the pollutant concentrations in urban
runoff can be quite high. From a management standpoint,
the implementation of storm water controls is usually
required following sewer separation in order to achieve the
necessary pollutant load reductions for attainment of water
quality standards.
Table 1. Typical pollutant concentrations.
Contaminant
Source
Untreated
wastewater
CSOC
Urban runoffd
Treated
wastewater6
(disinfected)
BOD5
(mg/L)
88-451"
4-699
0.41 - 370
12-140
TSS
(mg/L)
1 1 8 - 487a
4 - 4,420
0.5 - 4,800
0.5 - 35
Fecal Coliform
(#/100mL)
1,000,000-
1,000,000,000b
1,100-1,645,000
1 - 5,230,000
<200
' AMSA 2003
"NRC 1996
c Chapter 4 of EPA's 2003 Report to Congress on the Impacts and Control
ofCSOsandSSOs
o Pittef al. 2003
e EPA 2000
From a regulatory standpoint, implementation of
sewer separation satisfies the requirements of the CSO
Control Policy. However, the newly-created sanitary and
storm water systems become subject to existing NPDES
requirements for storm water and separate sanitary sewer
systems.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Some CSO communities find that more cost-effective
overall reductions in pollutant loads can be achieved with
the implementation of other CSO controls such as storage
and treatment, instead of sewer separation. Having the
storm water collected and conveyed in a CSS does present
some environmental advantages if most of the wet weather
flow is given the minimum treatment required by the CSO
Control Policy (i.e., the equivalent of primary treatment
and disinfection, if necessary).
From both cost and design standpoints, it is often difficult
to fully separate CSSs. The occurrence of occasional
residual overflows is common in many CSSs that have been
separated. The cost of full separation can be prohibitive,
and some communities opt for partial separation for this
reason. Several states require sewer separation to the extent
necessary to eliminate CSOs under specific design storm
conditions (i.e., the 2-year, 24-hour storm). This leaves
a legacy of infrequent but substantial CSOs during large
wet weather events or periods of snow melt. The difficulty
in achieving full separation can leave a community with
residual overflows that may be subject to potentially more
stringent requirements for SSOs.
Applicability
A major benefit of sewer separation is that it has the
potential to completely eliminate the CSOs and the
unwanted discharge of raw sewage to receiving waters from
an antiquated sewer system. Consequently, public health,
water quality, ecological, and aesthetic benefits can be
achieved through sewer separation. Another advantage of
sewer separation is the reduction of wet weather flows to
the wastewater treatment plant. Sewer separation diverts
storm water to a separate storm water system during
rainfall periods. The diversion of storm water reduces
system-wide stress and frees up sewer system conveyance
and wastewater treatment capacity. Sewer separation also
offers a solution to localized flooding and basement backup
problems caused by excess water entering the sewer system.
Public health and aesthetic benefits accrue where public
exposure to raw sewage in homes, businesses, and other
public areas is reduced.
Cost
Sewer separation is expensive relative to other CSO
controls, and full sewer separation is typically the most
expensive CSO control alternative evaluated in most
communities. Example unit costs for sewer separation are
presented in Tables 2 and 3.
Table 2. Sewer separation costs per linear foot of CSS.
CSO Community
Detroit, Ml:
Rouge River Project13
Cost per Linear Foot"
$175-$220
Syracuse, NY:
Onondaga Lake
Improvement Project11
$490 for residential areas
(estimate)
$610 for commercial areas
"Costs are in 2002 dollars
""Includes removing existing pavement, laying a new sewer line, re-
paving, and re-sodding
Includes a 25 percent contingency for mobilization, bonds, permits,
survey, stakeout, and drawings; does not include internal building
plumbing modifications
Table 3. Sewer separation costs per acre of service area.
CSO
Community
Seaford, DE
Skokie/
Wi Imette, ll-
St. Paul, MN and
surrounding
areas
Portland, OR
Providence, Rl
CSS Area
(Acres)
1,260
6,784
21,117
N/Ab
180
Reported Costs3
(Million)
$2.2
$2132
$374
N/A
$14.6C
Cost Per
Acre
$1,750
$31,397
$17,730
$19,000
$81,000
' Costs are in 2002 dollars
b Not available
Estimated costs; community found other CSO controls to be more cost
effective (NBC 2000)
Sewer separation can also be very disruptive. Disturbances
caused by construction activities required to implement
sewer separation are widespread and relatively long-lasting;
and include digging up roads, altering traffic patterns, and
potentially disrupting other utility services.
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Collection System Controls: Sewer Separation
Implementation Examples
RANDOLPH,VT
Sewer Separation
Responsible Agency: Town of Randolph
Population Served: 2,270 Randolph, a town of approximately 2,270, is located on the White River in
central Vermont. In 1990, the State of Vermont developed a CSO Control
Policy that encouraged sewer separation. Compliance requires elimination
of CSO discharges during any storm with precipitation less than 2.5 inches of rain over a 24-hour period. Randolph completed a
sewer separation program during the mid-1990s that consisted of construction of a new separate storm water system throughout
much of the downtown commercial district and adjacent residential areas. A total of 44 storm water catch basins were separated
from the CSS, which was approximately 85 percent of the catch basins that were known or suspected to be connected.
Since completion of the main CSO abatement program in 1996, Randolph has continued to implement additional CSO control
through separation of smaller combined sewer areas as part of road improvements under its capital improvement plan.This has
resulted in the separation of six additional catch basins. Currently, the town has separated 95 percent of its combined sewers. Post-
sewer separation monitoring has shown an 80 percent reduction in the duration of CSO events recorded at the CSO outfall located
at the wastewater treatment facility.This reduction is based upon data collected from a 20-month period from 1998-2000 compared
with data collected prior to CSO control. As of 1997, approximately $2.66 million had been spent on the town's CSO abatement
program.
Though significantly reduced, CSOs still occur,and Randolph plans to further its CSO abatement efforts through a plan that spans
six years (2001-2006) at a projected cost of $500,000. Planned projects include sewer line replacement and upgrades as well as
continued sewer separation.
Contact: Joe Mod, Town of Randolph
SEAFORD, DE
City-wide Sewer Separation
Responsible Agency: City of Seaford
Population Served:6,699 The City of Seaford, a community of 5,900, is located in southwestern
Service Area: Not Available Delaware. In 2002, Seaford completed a major sewer separation program
covering approximately 1.97 square miles. The goal of this program was to
Sewer System: 22.7 mi. of sewer _'
eliminate untreated CSO discharges into the Nanticoke River, a tributary of the
Chesapeake Bay,during periods of wet weather. Compliance with Delaware and
EPA regulations and water quality initiatives provided the driving force for this
program. In addition, the program was designed to benefit city residents and recreational users of the Nanticoke River. Prior to sewer
separation, Seaford's wastewater treatment plant was unable to process all the combined sewage captured by the CSS during wet
weather events.This led to frequent discharges at four CSO outfalls located in downtown residential and commercial areas.
The initial plan to separate the combined sewers of Seaford was developed in 1984 with the objective of complete separation.
Implementation of the entire program was scheduled in eight phases and took 18 years to complete, due to construction and
financial constraints.The entire combined sewer area has been separated (approximately 40 percent of the city). Efforts to control
the resulting storm water discharges to the Nanticoke River are currently underway. The cost of the sewer separation program was
$2.2 million.
Contact: Charles Anderson, City of Seaford
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Report to Congress on the Impacts and Control ofCSOs and SSOs
A I
ST. PAUL, SOUTH ST. PAUL,
AND MINNEAPOLIS, MN
Full Sewer Separation
Responsible Agency: Metropolitan Council Environmental Services
Division (MCES) and the cities of St. Paul, South St. Paul, and Minneapolis
Population Served: 2.5 million
Service Area: 3,000 sq. mi.
Sewer System: 600 mi. of sewer
Working cooperatively under the Metropolitan
Council's Environmental Services Division (MCES),
the cities of St. Paul, South St. Paul,and Minneapolis
completed a 10-year, $331 million dollar sewer
separation program in 1996 (MCES 1996). The
goal of this program was to reduce the pollutant
load delivered to the Mississippi River from CSO
discharges. Prior to sewer separation, the average volume of untreated CSO discharges from the metro areas was estimated at 4.6
BG per year, with discharges occurring on average once every three days. Separation of St. Paul, South St. Paul, and Minneapolis
combined sewers began in 1985 as part of an on-going capital improvement program, with construction initially scheduled to be
complete in 2025. Due to public demand,the Minnesota Legislature adopted an accelerated program aimed at completing the sewer
separation by 1995. Implementation of the program resulted in the installation of 189 miles of separate storm sewers and 11.9 miles
of new sanitary sewers.This amounted to separation of approximately 33 square miles of combined sewer areas: 6.66 square miles
in Minneapolis, 24.53 square miles in St. Paul, and 1.8 square miles in South St. Paul. The disconnection of roof leaders was also an
important component of the program as it was estimated that they contributed 20 percent of the CSO volume in St. Paul.
By design, the sewer separation program provided the opportunity to implement other municipal infrastructure improvements
during construction.These included:
• Repairof existing sewers
• Disconnection of 21,900 residential rain leaders from the CSS
• Replacement of 3,500 lead water services with copper pipes
• Upgrade of other local utilities
• Installation of 8,200 new street lights
• Installation of handicapped-accessible ramps
As a result of sewer separation, water quality in the Mississippi River and other local waterbodies has improved. MCES noted lower
fecal coliform bacteria levels in the river, the return of the pollution-sensitive Hexagenia Mayfly, and increases in fish populations.
Sewer separation is believed to be the major reason for the decrease in fecal coliform levels from an average of 500 MPN/100 ml
in 1976 to an average of 150 MPN/100 ml in 1995 in the waters below Minneapolis.The program also benefited local waterfront
development along the Mississippi River.
Contact Tim O'Donnell, Metropolitan Council
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Collection System Controls: Sewer Separation
References
Association of Metropolitan Sewerage Agencies
(AMSA). 2003. TheAMSA 2002 Financial Survey: A
National Survey of Municipal Wastewater Management
Financing and Trends. Washington, DC.
EPA. 2001. Report to Congress: Implementation and
Enforcement of the Combined Sewer Overflow Control
Policy. EPA/833-R-01-003.
EPA Office of Water. 2000. Progress in Water Quality:
An Evaluation of the National Investment in Municipal
Wastewater Treatment. EPA-832-R-00-008.
Metropolitan Council Environmental Services
(MCES). 1996. Separating Combined Sewers to Improve
and Protect Mississippi River Water Quality: A Ten-
Year Commitment, Annual Progress Report to the
Public - Year Ten. St. Paul, MN: MCES and Cities of
Minneapolis, St. Paul, South St. Paul.
The Narragansett Bay Commission (NBC).
2000. Storm Water Attenuation Study: Technical
Memorandum No.3 Evaluation Alternatives. Prepared
by MacGuire Group, Inc. Rhode Island: NBC.
National Research Council (NRC), Committee on
the Use of Treated Municipal Wastewater Effluents
and Sludge in the Production of Crops for Human
Consumption. 1996. Use of Reclaimed Water and
Sludge in Food Crop Production. The National
Academies Press.
Pitt, R. et al. 2003. "The National Stormwater Quality
Database (NSQD, version 1.0)." Retreived August 6,
2003. Tuscaloosa, AL: University of Alabama.http:
//www.eng.ua.edu/~rpitt/Research/ms4/Paper/
Mainms4paper.html
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
CSC-25
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RIPTION
Sewer Rehabilitation
Overview
The structural integrity of many sewer system components
has deteriorated from use and age. This gradual breakdown
allows greater amounts of groundwater and storm water
to infiltrate into the sewer system, which increases the
hydraulic load, and in turn, reduces the system's ability to
convey all flows to the treatment plant. During wet weather
events, excessive infiltration can cause or contribute to
CSOs and SSOs. There are many reasons why a system
may deteriorate to the point where infiltration becomes a
problem. These include (WEF 1999):
• Inadequate design and construction practices
• Inadequate or improper bedding material
• Root intrusion
• Pipe breakdown from chemical corrosion
• Traffic loadings
• Soil movement and settling
• Groundwater fluctuations
• Cracking and aging
• Inadequate installation and maintenance
Sewer rehabilitation helps restore and maintain the
structural integrity of a sewer system, in part by reducing
or mitigating the effects of infiltration. Specific sewer
rehabilitation techniques discussed in this description
include:
• Removing and replacing defective lines
• Shotcrete
• Trenchless methods
The presence of debris will limit the effectiveness of sewer
rehabilitation efforts; therefore, before initiating sewer
rehabilitation, it is essential to remove any debris or roots
that may be present in the sewer line. When rehabilitating
a sewer line, it is also important to consider rehabilitation
of system components, such as manholes and service
laterals, since these may also be subject to infiltration. More
information on sewer cleaning and manhole and service
lateral rehabilitation is presented in additional technology
descriptions included in Appendix B of Report to Congress
on the Impacts and Control of Combined Sewer Overflows
and Sanitary Sewer Overflows.
Removing and Replacing Defective Lines
In many cases, it is not practical or desirable to rehabilitate
existing sewers. Removing and replacing part or all of a
defective sewer is the most common and proven method
for eliminating inflow and infiltration (I/I), as well as
correcting other structural problems. Often called "dig-and-
replace," the original pipe is excavated and disconnected
from the sewer system. The pipe is then removed and
replaced with a new, often larger, pipe. Alternatively, a new
pipe may also be positioned parallel to the existing sewer
and connected to the sewer system.
Shotcrete
Shotcrete is a mix of cement, sand, and water that is applied
to the walls of the sewer using air pressure. Shotcrete
generally consists of 30 percent cement and 70 percent
sand (Shotcrete 2001). A welded wire mesh screen is often
constructed over the section to be rehabilitated to provide
additional support for the shotcrete mixture. The screen is
covered by at least one inch of shotcrete to create a smooth
surface. To apply shotcrete, the sand and cement mixture is
forced through a hose to a mixing chamber that contains
water. The mixture is then "shot" into place using air
pressure. Major structural problems can often be remedied
using shotcrete (CSU 2001).
Trenchless Technologies
Trenchless sewer rehabilitation technologies use the existing
sewer to support a new pipe or a liner. As the name implies,
trenchless technology requires less surface interruption
than to dig-and-replace a defective sewer line. Trenchless
technologies include sliplining, cured-in-place pipe (CIPP),
modified cross-section liners, and pipe bursting.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Sliplining
Sliplining involves placing a new, smaller diameter liner
in the existing sewer. The new liner is then grouted to
the existing pipe to improve structural integrity and
prevent leaks (EPA 1999). The sliplining process can
be continuous, segmented, or spiral wound. During
continuous installation, the total length of lining is
inserted at strategic locations. Segmented installation
requires the pipe liner to be broken into portions and
then assembled at access points in the sewer system. As
shown in Figure 1, spiral wound lining is interlocked
forming a spiral that is inserted into the pipe from a
manhole or other access point. Sliplining may require
access to the sewer line beyond that which a manhole
can provide; an insertion pit may need to be created.
Therefore, sliplining is not always a completely
trenchless technology, but it is much less intrusive than
traditional dig-and-replace methods (EPA 1999). Also,
sliplining is not applicable in force mains.
Existing
pipe
Spiral wound pipe
with interlocking
edges
Figure 1. Schematic of a spiral wound lining.
Cured-in-Place Pipe
During CIPP rehabilitation, a flexible fabric liner
coated with a thermosetting resin is inserted into the
existing sewer and then cured (EPA 1999). The most
common techniques for installing the liners are the
winch-in-place and invert-in-place methods. In the
former, a winch is used to pull the liner into place. The
liner is then filled with air to push it against the existing
pipe. When using the invert-in-place technique, the
resin is applied to the inside of the liner. Water or air
pressure is used to invert the liner so that the resin
covered side "flips out" to meet the existing pipe. For
both methods, heat is used to seal the liner to the pipe
(EPA 1999). CIPP liners can be installed from existing
Roller truck
Circulation
pump
Manhole
Heated water
Figure 2. Schematic of a cured-in-place technique (O'Brien
and Gere 2002)
manholes, making it a true trenchless technology, as
shown in Figure 2.
Modified Cross Section Lining
Modified cross section lining rehabilitation methods
modify the cross-sectional area of the liner to facilitate
its installation. The three most common techniques
are Swagelining™, deform and reform, and roll down.
Swagelining™ uses heat and a chemical dye to reduce
the size of the liner. After the liner is pulled through
the pipe and allowed to cool, it returns to its original
diameter. In the deform and reform method, a flexible
pipe is deformed, often forming a U shape, and is then
inserted into the existing pipe. The roll down technique
minimizes the size of the liner using a series of rollers.
Heat is used to reform the liner for both the deform
and reform and rolldown methods (EPA 1999).
Pipe Bursting
Pipe bursting uses the existing pipe as a guide for
an expansion head. A cable rod and winch pull the
expansion head, which cracks the existing pipe by
pushing it radially outwards. The new sewer line is
pulled behind the expansion head, as shown in Figure
3. Expansion heads are either static or dynamic; the
dynamic head provides additional pneumatic or
hydraulic force to counter the pressure created by
pulling the expansion head through the existing pipe
(EPA 1999).
CSC-28
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Collection System Controls: Sewer Rehabilitation
Pulling.
device
Pipe fragments Bursting head
In
New pipe
I—^
Expander (if used)
Cable or
chain
Figure 3. Schematic of pipe bursting technique.
Key Considerations
Applicability
In selecting a sewer rehabilitation technique, site-specific
conditions, project goals, and sewer system characteristics
should be evaluated. Inspection and evaluation of the
current sewer condition are necessary before a sewer
rehabilitation technique is chosen, as the condition of the
sewer may favor specific techniques. Additional information
on sewer inspection techniques is provided in the "Sewer
Testing and Inspection Technology Description" located
in Appendix B of Report to Congress on the Impacts and
Control of Combined Sewer Overflows and Sanitary Sewer
Overflows.
Removing and Replacing Defective Lines
Removing and replacing defective lines is the most
commonly used rehabilitation technique when the sewer
line is structurally deficient. Replacing defective lines
results in a line segment design life that exceeds any other
rehabilitation method. Also, in areas in need of increased
conveyance capacity, complete replacement provides an
opportunity for installation of a larger-diameter sewer
(WEF 1999). Sewer replacement can be quite disruptive to
automotive and pedestrian traffic, however. Construction
times and service interruptions for replacement are
typically lengthy compared to other rehabilitation
methods. In addition, sewer flows must be rerouted during
construction. Construction costs are also considerably
higher for dig-and-replace than for other rehabilitation
methods (EPA 1991).
Shotcrete
Shotcrete is often used to rehabilitate sewers with major
structural problems. As with dig-and-replace, flow must be
completely diverted during construction since equipment
and personnel must access the pipe. Shotcrete may only be
used in pipes with a diameter greater than 36 inches.
The advantages of using shotcrete include (CSU 2001):
• Rehabilitation can be accomplished using manholes to
access the sewer system;
• Restoration of the original pipe strength; and
• Method is safer for crews than grouting and epoxy
injections.
Disadvantages of shotcrete include (CSU 2001):
• A long curing time;
• Complete diversion of the flow during application; and
• Reduction in hydraulic capacity because the diameter
of the sewer is reduced.
Trenchless Technologies
Trenchless technologies are especially well-suited to urban
areas where the traffic disruption associated with large-
scale excavation projects can be a significant obstacle to a
project (WEF 1999). In addition, many sewers are located
near other underground utilities in urban areas which can
Tablel. Sewer system characteristics for trenchless
technologyies (CSU 2001).
Method
Grouting and Epoxv Injections
Remote Application
Manual Application
Sliplining
Continuous
Segemented
Spiral wound
CIPP
Invert-in-Place
Winch-in-Place
Modified Cross Section Liners
Swagelining™
Deform and Reform
Rolldown
Pipebursting
Pneumatic Head
Static Head
Diameter
Range (in.)
4-63
12-158
4-100
4-54
4-100
4-24
4-64
4-24
2-24
4-24
Maximum
Installation
(ft.)
Not Available
1,000
5,600
300
500
3,000
300
300
300
475
650
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Report to Congress on the Impacts and Control ofCSOs and SSOs
complicate traditional dig-and-replace methods; trenchless
technologies avoid underground utilities.
Advantages of trenchless technologies include (EPA 1999):
• Reduced air pollution from construction equipment
• Fewer traffic detours
• Decreased construction noise
• Reduced vegetation disturbance
• Limited areas where safety concerns must be identified
Table 1 highlights conditions for which various trenchless
technologies are most applicable. Trenchless technologies
are not without limitations, however, and they are
summarized in Table 2.
Table 2. Disadvantages of trenchless sewer rehabilitation
technologies (EPA 1999).
Method
Grouting and Epoxy
Injections
Sliplining
CIPP
Modified Cross
Disadvantage
1 Utilize harsh chemicals that may be
dangerous for installation crews
1 Will not prevent further pipe
movement, and may crack if pipe shifts
1 Requires an insertion pit
1 Reduces pipe diameter
1 Cannot be used with small diameter
pipes
• Curing can be difficult for long pipe
sections
1 Requires diversion of flow
1 Resin can clump together
1 Reduces pipe diameter
Liner may shrink after installation
Section Liners • Infiltration may occur between pipe
and liner
• Liner may not provide adequate
structural support
• Requires dversion of flow
• Reduces pipe diameter
Pipe Bursting • Insertion pit needed
• Dynamic head may cause soil settling
around the newly installed pipe
• Requires diversion of flow
• Not suitable for all pipe materials
Cost
Selection of a cost-effective sewer rehabilitation technique
depends on the present condition of the sewer and other
site-specific considerations. In general, grouting is the least
expensive of the sewer rehabilitation methods presented.
Further, trenchless sewer rehabilitation techniques are often
less expensive than open-cut methods because the amount
of excavation for the trenchless technology is minimal
(EPA 1999). A representative range of costs for several
trenchless technologies (CIPP, sliplining, and pipe bursting)
is presented in Table 3; actual costs for sewer rehabilitation
projects undertaken by a number of municipalities are
summarized in Table 4. As shown in Table 4, there is
considerable variation in the cost per foot for an individual
technology; the diameter of the pipe drives much of this
variation. Figure 4 illustrates the increase in cost of CIPP
replacement as a function of increasing sewer diameter.
Tables. Cost of selected trenchless technologies.
Technology
CIPP
Sliplining
Pipe Bursting
Cost ($/foot)
42-1200
10-560
46-260
l/l
£" "o
~ ~ 200
D 4J
X
.X
^/
^^
^iif***~'
^___^^--^"^^
~~~
20 25 30 35 40 45 50
Pipe Diameter (inches)
Figure 4. CIPP cost versus pipe diameter (Zhao etal. 2001).
CSC-30
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Collection System Controls: Sewer Rehabilitation
Table 4. Costs of municipal sewer rehabilitation projects.
Municipality Technology Project Characteristics
Buffalo, NY Shotcrete
Shotcrete was applied to 1,465 linear feet of
the Military Road sewer that was over 50 years
old.The pipe diameter tapered down from 53
to 48 inches.
Year Costs1
Constructed
1997 Approximate cost:
$280,552 or $192 per foot
Indianapolis, IN Shotcrete
Trenchless
After sewer evaluation was performed a
total of 12,495 feet for sewer have been
rehabilitated using Shotcrete, CIPP,and
sliplining.
1998-2002 $4 million or $317 per foot
St. Louis, MO Open-Cut
1,560 feet of sewer were replaced, providing
surcharge relief to upstream sewer system.
Costs include all excavation, refill,and
engineering costs.
2002
$535,000 or $343 per foot
Austin,TX
Open-Cut
Trenchless
The Austin Clean Water Program is a
comprehensive project to eliminate SSOs from
the city's sanitary sewer system.
The project will be complete by 2007.
2002
(construction
started)
Cost for Crosstown Tunnel
Service Area:
$44 million or $530 per foot
Torrence, CA2 Open-Cut
Trenchless
8,400 feet of pipe was rehabilitated.
90 percent of the sewers were repaired using
machine spiral wound PVC pipe liner.
Open-cut methods were used for the
remaining sewers.
2002 Total construction cost:
$530,000
Open-cut:
$191,000 or $955 per foot
Trenchless:
$339,000 or $41 per foot
DuPage Trenchless
County, IL
U-liner to rehabilitate 24,000 feet of 8-inch and
4,000 feet of 10-inch VCP mains.
1994 8- tol 2-inch U-Liner:
$34-$44 per foot
Glendale,WI Trenchless
U-Liner was used to repair 3,462 feet of eight
to 10 inches pipes; CIPP was used for 1,966
feet of 15-inch pipes..
1999 8-to 10-inch U-Liner:
$29-$33 per foot
15-18 inches CIPP:
$58-68 per foot
Muscatine, IA Trenchless
CIPP method was used to rehabilitate 3,800
feet of 24- to 27-inch diameter pipes and 187
feet of 8-inch clay pipes.
2001 24-to 27-inch CIPP:
$67-$ 103 per foot
South Fayette Grouting
Township, PA
Pilot program grouting a total of 2,788 feet was
conducted.
A total of 303 gallons of acrylmide grout was
used.
1997
$33,475 or $12 per foot
Dallas,TX Grouting
Approximately 10,000 feet of pipe were
cleaned, tested, and sealed as part of a project
to eliminate I/I.
2000
$89,331 or $9 per foot
1 All costs are converted to 2002 dollars based on the ENR Construction Cost Index
2 Costs include traffic control, which increase the cost per linear foot; total construction cost was $530,000 (Ringland 2003)
CSC-31
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Implementation Examples
AUSTIN, TX
Clean Water Program to Control SSOs
^
Responsible Agency: City of Austin Water and
Wastewater Utility
Population Served: 1 million
Service Area: 364 sq. mi.
Sewer System: 2,262 mi. of sewer
In April 1999, the City of Austin received an Administrative Order from EPA
requiring it to eliminate SSOs by 2007. The order stemmed from a review of
Austin's sewer system performance following a 170,000 gallon SSO to Bushy
Creek, a tributary of the San Gabriel River.To comply with the order, the city
created the Austin Clean Water Program. The order requires inspection of
approximately 40 percent of the city's 2,200 mile sewer system, and, where
appropriate, the rehabilitation of failing sewer lines. The project is broken
up into three areas, Crosstown Tunnel Service Area, Onion Creek Service Area, and Govalle Tunnel Service Area, which are being
inspected and rehabilitated in a phased approach.To date,500,000 linearfeet have been rehabilitated using sliplining and open-cut
methods.
The total cost estimate for the Austin Clean Water Program is $150 million, which includes an I/I study and sewer system evaluation
and rehabilitation projects in each service area. Estimated cost for the rehabilitation completed in the Crosstown Tunnel Service Area
is approximately $44 million or $530 per linear foot.
More information athttp://www.ci.austin.tx.us/acwp/
MIAMI, FL
/// and Rehabilitation Program
Responsible Agency: Miami-Dade Water and Sewer
Department
Population Served: 2.1 million
Service Area: Not Available
Sewer System: 2,441 mi. of gravity sanitary sewer
The Miami-DadeWaterand Sewer Department (MDWASD) initiated
an infiltration/inflow and rehabilitation (I/I & R) program in 1995 in
response to an EPA consent decree.The I/I & R program established
an ongoing sewer evaluation and rehabilitation schedule to
preserve the sewer system's integrity and maintain acceptable
levels of I/I. The I/I & R program includes sewer cleaning, CCTV
inspection, smoke testing, dye water flooding, and system rehabilitation.
Approximately 14.5 million feet of sanitary sewer have been inspected and rehabilitated. Sewer rehabilitation methods include dig-
and-replace, sliplining,and grouting. Over 32,000 repairs have been completed, helping to reduce SSO volumes by 90 percent and I/I
by an estimated 118 MGD since program inception. MDWASD believes the I/I & R program is working; for example, in June and July
2002, the area received more than 20 inches of rain, but the sewer system experienced no capacity-related SSOs.The total cost of the
I/I & R program, since its inception, has been approximately $174 million or $12 per foot of sewer inspected or rehabilitated.
More infromation at http://www.co.miami-dade.fl.us/wasd/
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Collection System Controls: Sewer Rehabilitation
COLUMBUS, OH
Sewer Inspection and Rehabilitation Program
Responsible Agency: Department of Public
Utilities, Division of Sewage and Drainage
Population Served: 1 million
Service Area: 219 sq. mi.
Sewer System: 4,000 mi. of sanitary and
combined sewer
In 1995, the City of Columbus initiated a sewer line inspection and rehabilitation
program.To assure the quality of products used by contractors in the program,
the city developed a list of approved rehabilitation technologies. When a new
technology or product of interest emerges, the manufacturer may request to
have their product added to the approved list.The city has developed a process
to standardize the introduction of new products.The process requires that:
The products meet and conform to American Society for Testing and Materials (ASTM) and other professionally
recognized standard specifications.
The products must have been used successfully by three municipalities over a minimum of three years.
The city visits both construction sites and product manufacturing facilities to inspect operation and observe standard
construction practices.
The manufacturer provides information on the expected service life of the product with supporting data.
When a product is selected for preliminary review, it is installed in a small portion of the
city's sewer system.The product's effectiveness is then monitored for three years. Once
the product is judged effective, it can be placed on the list of approved technologies.
The current list of approved technologies includes several CIPP products, sliplining,
and shotcrete. These technologies have been utilized to repair numerous sections of
structurally impaired combined sewers. The city has recently started rehabilitating
sanitary sewers using the approved technologies.
Sewer rehabilitation is a priority for Columbus, and the program has been funded
accordingly. The dollars spent on sewer rehabilitation between 1996 and 2001
are shown in the table on the right. Costs presented do not include construction,
administration,and inspection costs.
Construction Dollars Spent1
(Millions)
1996 $6.5
1997 $2.6
1998 $5.9
1999 $2.6
2000 $6.8
2001 $9.3
1 All costs are converted to 2002 dollars based
on the ENR Construction Cost Index
Contact: Miriam Siegfried, Department of Public Utilities, City of Columbus
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Report to Congress on the Impacts and Control ofCSOs and SSOs
N7 1C Greater Houston Wastewater Program
Responsible Agency: City of Houston In 1987, the Texas Natural Resource Conservation Commission and EPA
Department of Public Works and Engineering mandated that Houston eliminate the 200 known SSO points that were
Population Served: 1.9 million part of their sanitary sewer system by 1997.The first step the city took was
Service Area-600 sq mi to inspect over 27 million linear feet of sewer.The results of the inspections
Sewer System: 5,000 mi. of sanitary sewer were used to rate each sewer Se9ment The ratin9 took into account the
severity of I/I, roots, concrete deterioration, and structural defects. The
| inspection program found that 50 percent of the inspected sewer segments
were in need of rehabilitation or replacement.
To help prioritize the numerous rehabilitation projects, the city developed a numeric sewer rehabilitation rating system, which
considered:
• Accessibility of the line
• Potential future capacity requirements
• Surrounding environment
• Cost
Prior to rehabilitation,a second analysis was performed to determine the most appropriate technique.The analysis considered:
• Current condition of the sewer line
• Maximum service capacity
• Hydraulics
• Site constraints
In areas that were fully built-out, with no future plans for redevelopment, trenchless technologies were generally used for sewer
rehabilitation. Where trenchless technologies were utilized, a hydraulic analysis was performed to determine if reducing the inner
diameter of pipe would cause capacity constraints that could lead to SSOs. For sewers where the use of trenchless technologies
yielded an unacceptable reduction in pipe diameter, or areas where undeveloped land was still available, lines targeted for
rehabilitation were typically replaced with a larger pipe to add additional capacity.
Technologies approved for use by the city included sliplining, cured-in-place pipe, pipe bursting, and limited use of modified cross-
section liners. The city rehabilitates approximately 120 miles of sewers annually using trenchless technologies. The city committed
to spend a total of $300 million on sewer rehabilitation as part of the settlement with EPA.
Con tact: Teresa Battenfield, City of Houston, Department of Public Works and Engineering
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Collection System Controls: Sewer Rehabilitation
INDIANAPOLIS,!
N
Combined Sewer Infrastructure Assessment
Responsible Agency: City of Indianapolis
Department of Public Works
Population Served: 800,000
Service Area: 58.4 sq. mi.
Sewer System: 82.2 mi. of combined sewer
The Indianapolis Combined Sewer Infrastructure Assessment Project
investigated the integrity of approximately 50 miles of sewer with diameters
of 60 inches or larger.The city used the study to identify sewers in need of
immediate rehabilitation and to develop the basis for a more integrated
Capital Improvement Program.This project was also important to the city
in developing its CSO long-term control plan.The city wanted to maximize
storage in the existing sewer system, but needed to be sure that the pipes
used to store flows were structurally sound. If a weak sewer pipe was stressed to the point of failure in using it for storage, the
environmental impacts could be much larger than those attributed to a single CSO event. Approximately 253,000 feet of brick,
concrete,and vitrified tile combined sewer were physically inspected and rated based on their structural integrity between 1994 and
1998. The study found that the majority of sewers were in good condition, identifying approximately 71,000 feet (28 percent of the
assessed length) in need of rehabilitation. Since the Assessment Project was completed in 1998, a total of 12,495 feet of sewer have
been rehabilitated.The city has used shotcrete,CIPP,and sliplining techniques to rehabilitate their large diameter combined sewers.
The total cost for the Assessment Project was $1.1 million. An additional $4 million or $317 per foot has been invested in targeted
sewer rehabilitation.
Contact: T.J. Short, Greeley and Hansen
References
EPA. 1991. Sewer System Infrastructure Analysis and
Rehabilitation. EPA 625-6-91-010.
EPA. 1999. Collection Systems O&M Fact Sheet: Trenchless
Sewer Rehabilitation. EPA 832-F-99-032.
California State University (CSU), Sacramento - College
of Engineering and Computer Science, Office of Water
Programs. 2001. Operation and Maintenance ofWastewater
Collection Systems. Vol. 1, 5th ed. Prepared for EPA Office
of Water Programs, Municipal Permits and Operations
Division. Sacramento, CA: CSU, Sacramento Foundation.
Ringland, David, City of Torrence. Interview with Limno-
Tech, Inc., March 2003. Washington, DC.
Water Environment Federation (WEF). 1999. Prevention
and Control of Sewer System Overflows: WEF Manual of
Practice No. FD-17. Prepared by Gray, W et al. Alexandria,
VA: Water Environment Federation.
Zhao, J. Q. et al. 2001. Guidelines for Condition Assessment
and Rehabilitation of Large Sewers. Ottawa, Canada:
Institute for Research in Construction, National Research
Council Canada. Report No. NRCC-45130.
National Research Council Canada (NRC). 2002.
Construction and Rehabilitation Costs for Buried Pipe with
Focus on Trenchless Technologies. Research Report No. 101.
Ottawa, Canada: National Research Council Canada.
O'Brien & Gere. 2002. 'Wastewater Management: Trenchless
Technologies.'Viewed December 17,2002.
http://www.obg.com/wastewater/pdf/Trenchless_Syr(l).pdf
Shotcrete Technologies, Inc. 2001. "Shotcrete Tips and
Tricks: Mix Design and Quality Control." Retrieved
February 21,2003.
http://www.shotcretetechnologies.com/tips.html
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
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RIPTION
Service Lateral
Rehabilitation
Overview
Private building service laterals (herein referred to as
"service laterals") are the pipe or pipes used convey
wastewater from individual buildings to the municipal
sewer system. Typical service laterals are four to six inches
in diameter, with lengths ranging from 15-100 feet. Service
laterals are often thought of in two segments: the upper
lateral, which includes the section of pipe between the
building and private property boundary; and the lower
lateral, which includes the section of pipe between the
private property boundary and the municipal sewer system.
For many years, the effect of leaking service laterals was
considered insignificant because it was assumed that
most service connections were above the water table, and
therefore, subject to infiltration only during periods of
excessive rainfall or high groundwater levels (EPA 1991).
More recent studies indicate that a significant component
of the infiltration in any sewer system is the result of
service lateral defects that contribute varying quantities
of inflow and infiltration (I/I) to the sewer system.
Many of these defects are traceable to poor design, pipe
selection, and improper construction (WEF 1999). Further,
fluctuating groundwater levels, variable soil characteristics
and conditions, traffic, erosion, and washouts stress service
lateral pipes and joints. As shown in Figure 1, the most
common problems found in service laterals include:
• Improper connections
• Faulty pipe joints
• Root intrusion
• Failure of service lateral bedding or backfill to support
the pipe
• Pipe material failure in aging service laterals
• Missing or broken cleanout caps
Service lateral testing is an important first step in any
rehabilitation program. Testing is used to assess the
structural condition of the service lateral and to help locate
defects. Additional information on sewer testing practices is
provided in the "Sewer Testing and Inspection Technology
Description" in Appendix B of Report to Congress on the
Impacts and Control of Combined Sewer Overflows and
Sanitary Sewer Overflows.
Improper
connection
Faulty joint
Root intrustion
Figure 1. Common defects in service laterals.
There are a number of techniques available for repairing
defective service laterals. These include:
• Removing and replacing defective service laterals
• Spot repairs
• Trenchless technologies
• Eliminating inflow sources
These four techniques are discussed in some detail below.
Removing and Replacing Defective Service Laterals
In many cases, it is not practical or desirable to rehabilitate
existing sewers. Removing and replacing part or all of a
defective service lateral is the most common and proven
method for eliminating I/I from private property. A key
factor to a successful program using remove and replace is
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Report to Congress on the Impacts and Control ofCSOs and SSOs
obtaining the private property owners' consent to access the
property for construction.
Spot Repairs
Spot, or point, repairs are typically used to correct isolated
or severe problems in relatively short portions of a service
lateral. Spot repairs can also be made as an initial step
in the use of other rehabilitation methods (NASSCO
1996). Spot repairs can be made using either open cut or
trenchless technologies. The open-cut technique involves
excavating and removing the defective section, and then
installing new pipe with proper seals to ensure watertight
connections to the existing service lateral and/or municipal
sewer system. Trenchless technologies for spot repairs
typically use epoxy or resin to fill defects; in general, their
use is limited to service laterals with a diameter of six
inches or more.
Trenchless Technologies
Trenchless service lateral rehabilitation uses the existing
pipe to support a new pipe or a liner. Generally, the use
of trenchless technology methods is neither as widespread
nor extensive as open cut techniques for repairing service
laterals (WEF 1999). As the name implies, trenchless
technology requires less surface interruption than complete
replacement of a defective line. Therefore, trenchless
technologies show particular promise in areas where
construction impacts on trees, shrubbery, and other
landscaping materials would make open-cut service lateral
repair costs prohibitive. Trenchless rehabilitation techniques
include lining, cured-in-place pipe (CIPP), pipe bursting,
grouting, and epoxy injections.
Lining Service Laterals
Lining service laterals is typically used to extend
the life of an existing service lateral by increasing
its strength and/or protecting it from corrosion or
abrasion (NASSCO 1996). Lining involves sliding a
flexible liner pipe of slightly smaller diameter into the
existing lateral. The space between the liner and the
existing service lateral is then grouted. Lining is most
often used to rehabilitate extensively cracked laterals,
especially those in unstable soil conditions. The most
popular materials used to line sewers are polyolefins,
reinforced thermosetting resins, and PVC (EPA 1991).
The lateral must be thoroughly cleaned prior to lining.
Typically, lining the service lateral requires excavating
an entry point at both upstream and downstream ends
to be able to insert and move the liner into position.
Therefore, similar to remove and replace and open-cut
spot repairs, lining service laterals requires private
property access.
Cured-in-Place Pipe
The cured-in-place pipe (CIPP) process involves
installing and curing a resin-saturated, flexible fabric
liner inside the service lateral. The liner is installed
using air or water inversion or a pull-in process. With
water inversion, the lining is inverted using water
pressure; air inversion uses air pressure to invert the
liner. The pull-in process involves winching the liner
into place and using an air bladder to "inflate" the liner.
The liner is then cured by circulating low pressure hot
water or steam. The lateral must be thoroughly cleaned
prior to installing the CIPP, and areas with excessive
infiltration must be sealed. Typically, installing CIPP
liners requires excavating an entry point at either the
upstream or downstream end. Therefore, installing
CIPP liners may not require private property access.
Pipe Bursting
Pipe bursting replaces the existing lateral with a pipe of
similar or larger diameter by fragmenting the existing
pipe into the surrounding soil, thereby creating a cavity
for the new pipe. Pipe bursting has been used in the
gas industry for some time, but only more recently has
been looked at for rehabilitating service laterals. Similar
to lining a lateral, excavated entry points at both the
upstream and downstream ends of the service lateral
are required, which requires private property access.
Grouting and Epoxy Injections
Grouting and epoxy injections are most commonly
used for sealing leaking joints in pipes that are
otherwise structurally sound (NASSCO 1996).
Small holes and radial cracks may also be sealed by
grouting or epoxy injections. Grouts and epoxies are
applied internally within a pipe and are a trenchless
rehabilitation method.
Eliminating Inflow Sources
Service lateral cleanouts allow access to the lateral
for routine maintenance. Often, the cap used to
prevent storm water inflow into the service lateral at
the cleanout is broken or missing. One study found
that almost 25 percent of service lateral defects were
related to missing or damaged cleanout caps (Rowe
and Holmberg 1995). Replacing missing or defective
cleanout caps can result in substantial reductions in
inflow into the sewer system.
Although disconnecting inflow sources is not a repair
of the service lateral per se, elimination of direct
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Collection System Controls: Service Lateral Rehabilitation
connections of extraneous storm water is important.
Other, often significant inflow sources include:
• Roof leaders
• Area, foundation, yard, patio, and driveway drains
• Basement sump pumps
• Cross-connections to separate storm sewers
Additional information on disconnecting inflow
sources is provided in the "Inflow Reduction
Technology Fact Sheet" in Appendix B of Report to
Congress on the Impacts and Control of Combined Sewer
Overflows and Sanitary Sewer Overflows.
Key Considerations
Applicability
Assigning responsibility for the repair or replacement of
service laterals has often been cited as the biggest obstacle
to correcting known defects. Notably, several studies
highlighted significant problems in gaining access to private
property until the municipality assumed full financial
responsibility for the repair or replacement of service
laterals (Curtis and Krustsch 1995; Paulson et al. 1984).
Removing and Replacing Defective Service Laterals
The removal and replacement of a service lateral is
usually more expensive than other rehabilitation methods.
Replacing a defective service lateral, however, ensures that
the design capacity of the lateral is maintained, whereas
rehabilitation may result in an unacceptable reduction in
capacity. Construction activities associated with removal
and replacement involve a greater risk of damage to or
interruption of other utilities than most trenchless lateral
rehabilitation techniques.
Spot Repairs
Spot repairs are often a cost-effective means of addressing
minor defects in service laterals. While spot repairs
eliminate infiltration at the location of the repair they are
typically not an appropriate approach for rehabilitating
a lateral with multiple defects. Without correcting all of
the defects in a given lateral, groundwater will simply
find another location to enter the pipe. Depending on
the number and type of defects in a given lateral, it
may be more cost-effective to address the infiltration by
rehabilitating the entire length of the lateral.
Trenchless Technologies
Trenchless sewer rehabilitation techniques require
substantially less construction work than traditional
remove-and-replace methods (EPA 1999). However, with
the exception of pipe bursting, trenchless technologies
reduce the lateral diameter, resulting in decreased capacity.
Lining Service Laterals
To date, there has been limited experience using liners
to rehabilitate service laterals, although application
is expected to increase (WEF 1999). In lining service
laterals, particular attention must be paid to local
plumbing codes, specifically, whether changes will be
required to accommodate the reduced interior diameter
of the lateral after it is lined.
Pipe Bursting
The primary advantage of pipe bursting is that the flow
carrying capacity of the existing lateral does not have to
be reduced; further, pipe bursting allows the new lateral
to be up-sized, if needed. In addition, the amount of
surface disruption associated with pipe bursting is less
than that required for total lateral replacement. The soil
type surrounding the existing lateral is an important
variable when considering pipe bursting. In soils that
are predominated by sand, the soil "relaxes" almost
instantaneously onto the new pipe causing very slow
progress. It is also important to ensure that no large
boulders or rock formations are located in the path of
the pipe bursting equipment. Finally, the forces exerted
by the bursting equipment may adversely affect other
pipes near the lateral being replaced. Unit replacement
costs with pipe bursting are typically 20-40 percent
lower than traditional open cut methods.
Cured-in-Place Pipe
The use of CIPP for rehabilitating laterals with
diameters as small as four inches is common (NASSCO
1996). Unlike other types of lining, CIPP does not
require grouting. Although the installation of a CIPP
liner is rapid, the curing period can be extensive, and
flow and groundwater infiltration in the lateral will
need to be controlled during installation. CIPP also has
relatively high set-up costs for small projects.
Grouting and Epoxy Injections
Grouting is relatively inexpensive. Grouting does not
improve the structural strength of the lateral, and for
that reason, should not be considered when the pipe
is severely cracked, crushed, or badly broken (EPA
1991). Epoxy injections, although similar to grouting in
most respects, provide the added benefit of improving
somewhat the structural integrity of the rehabilitated
pipe. Because epoxy is more viscous than grout, it
cannot be pumped as far (WEF 1999). The service life
of grout is an important consideration. The average
service life of grouts is seven years (NASSCO 1996).
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Grouting requires flow control, because the section
being grouted cannot transport flow until the grout
has cured. Therefore, it is also difficult to line service
laterals if infiltration is present. Most coatings cannot
be successfully applied to either water leaks or ponded
water (NASSCO 1996). Large cracks, badly offset joints,
and misaligned pipes may not be scalable using grouts
or epoxies.
Eliminating Inflow Sources
Eliminating sources of inflow can be an efficient way
to reduce the volume of storm water delivered to
both combined and separate sanitary sewer systems.
The feasibility of disconnecting inflow sources
depends on the soil type, land slope, and drainage
conditions around the home. Additionally, for an
inflow disconnection program to be successful, the
public must be educated about the benefits of and the
methods for disconnecting sources. This can be time-
consuming and will likely require some sort of rebate
program or other incentive for compliance.
Cost
Often, very little specific data are available to compare the
I/I contribution from service laterals with that from other
sewer system components. Flow meters are rarely used to
monitor individual service laterals for reasons including
it is physically difficult to isolate service laterals from the
sewer system for installing flow meters; placing flow meters
in a service lateral requires significant and often expensive
modifications; and the large number of service lateral
connections can make sampling representative locations
costly. Rehabilitating service laterals, however, has proven
to be a critical component of an I/I reduction program.
Studies have found that service lateral rehabilitation can
reduce the introduction of extraneous I/I into the sewer
system from 45-87 percent (Rowe and Holmberg 1995;
Curtis and Krustsch 1993; EPA 1985; Roberts 1979).
Actual I/I reductions achieved, however, are dependent on
a number of factors, and therefore the cost-effectiveness
of lateral rehabilitation will vary from community to
community.
Costs associated with the various techniques available for
rehabilitating or replacing service laterals vary considerably
and are driven by site-specific conditions. Table 1 presents
the relative costs of the various techniques discussed in this
technology description. For example, replacing a service
lateral, either using open cut or pipe bursting techniques,
is almost always more expensive than other rehabilitation
alternatives. The exact cost of replacing the lateral, however,
will be driven by the landscape and length of the lateral
among other factors.
Table 1. Relative cost of various service reheabilitation costs.
Technique Relative Cost
Removing and replacing service laterals $$$$
Spot repairs $
Lining service laterals $$
Grouting and epoxy injections $$
Eliminating inflow sources $$
Implementation Examples
DARIENJL
Hinsbrook Subdivision I/I Rehabilitation
Responsible Agency: DuPage County Public |n the early 1990s, the DuPage County Public Works Division initiated efforts to
Works Division control I/I in the Hinsbrook Subdivision, which suffered from frequent SSOs. A
Population Served: 585 single family homes study of the sewer system determined that 25-30 percent of the I/I was entering
from the sewer system service laterals. Rehabilitation of the service laterals was
necessary, but politically complicated as it involved coordinating three groups:
the Public Works Division of DuPage County, the Public Works Department of the City of Darien,and the property owners. DuPage
County owns the SSS, while the City of Darien is responsible for storm water control in the subdivision, and property owners are
responsible for the portion of the service lateral on their property.
Pipe bursting was used to rehabilitate the majority of the service laterals in the subdivision. Property owners were informed in
advance of the replacement and given the option of hiring their own contractor or allowing the county to make the needed repairs.
Only 35 homeowners chose to hire their own contractor. For the pipe bursting, a small pit was excavated at the foundation of each
home. The pipe bursting head and new pipe were pulled with a winch from a pit located near the main pipe. The new service
lateral was then connected to the house and the service main. Installation time averaged two hours limiting the time service was
interrupted. Property owners who chose to have the county rehabilitate their service lateral paid the county $966.
More information at http://www.dupageco.org/publicworks/index.cfm
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Collection System Controls: Service Lateral Rehabilitation
MONTGOMERY. AL
/// Tracking and Service Lateral Rehabilitation
Responsible Agency: Montgomery Water Works and Montgomery Water Works and Sanitary Sewer Board (MWWSSB)
Sanitary Sewer Board evaluated the condition of its sewer system in the early 1990s and
Population Served: 225,000 discovered inflow sources could be cost-effectively eliminated in
Service Area: 150 sq. mi. 86 percent of the system. Nearly 2.2 million linear feet of pipe were
Sewer System: 1,098 mi. of sewer investigated in the first five years of the program. Of the 3,394 sewer
system problems detected, 85 percent were service lateral problems; a
defect was found in approximately every 700 feet of sewer inspected. Of
the 113 subbasins served by MWWSSB, 35 were smoke tested in the first six years of the program; 97 percent of the lateral defects
identified have been repaired.
Lateral maintenance and repair has always been the responsibility of the property owner, who was notified when defects were
discovered. Due to the number of defects identified, MWWSSB adopted a more aggressive maintenance and repair policy. Property
owners initially received a 60-day notice of the lateral repair requirements. If they failed to respond to the initial notice, a 10-day
notice was sent to the property owner. Finally, if the property owner had not responded to either notice, their water service was
shut-off.
Lateral repairs necessary within the city street right-of-way are made by MWWSSB with consent and release of liability from the
property owner. MWWSSB also replaces missing clean-out covers for a minimal cost with written permission from the property
owner.
To help manage the numerous service lateral repairs, MWWSSB created a sewer maintenance database. The database includes
information regarding when smoke testing was initiated, any defects found during testing, digital photos of the defect, when the
first owner notice was generated,and any repairs that were performed.
The public notice process was implemented in the Fall of 1994; 65 percent of property owners responded after receiving the 60-day
notice.The remaining property owners repaired their defects under threat of having their water service discontinued. In selected
subbasins where service lateral rehabilitation is complete, a 42 percent reduction of I/I has been measured.lt is estimated that the
annual I/I volume in the MWWSSB service area has been reduced by 36 million gallons.The initial cost of establishing the I/I program
was approximately $150,000; MWWSSB annual program operation costs are $207,000.
Contact: Danny Holmberg, Montgomery Water Works and Sanitary Sewer Board
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Report to Congress on the Impacts and Control ofCSOs and SSOs
o
ORLANDO. FL
Lateral Lining Program
Responsible Agency: City of Orlando Public
Works Department,Wastewater Bureau
Population Served: 200,000
Service Area: 104sq. mi.
Sewer System: 500 mi. of sanitary sewer
The City of Orlando Public Works Department (PWD) is responsible for the
maintenance and repair of the city's sewer system. Service laterals in the sewer
system are made from several different materials, including clay (45 percent),
PVC (35 percent), and concrete (20 percent). PWD found that the clay and
concrete pipes were particularly prone to I/I problems and that root intrusion
was the most common defect in service laterals.
PWD began to excavate and replace laterals from the property line to the main sewer. Excavation was expensive and disturbed the
local landscape and traffic patterns,frustrating residents. PWD looked into various trenchless technology options and selected CIPP
liners installed using an air inversion system to rehabilitate laterals.
PWD only rehabilitates laterals from the property line to the main sewer. Lateral rehabilitation begins when city crews excavate the
lateral at the property line.The crew then performs an initial inspection,and the proper length of liner is prepared and impregnated
with resins.The liner is installed into the host pipe by inflating a bladder that forces the liner into the pipe and causes it to adhere to
the walls of the host pipe. After a two-hour curing period, the bladder is deflated and removed. After a final inspection, the pipe is
reconnected and the excavation site is resodded. It is estimated that this process takes four to five hours per lateral. It is believed that
this system will help mitigate SSOs by controlling I/I into the system and will reduce service calls.The equipment for this program
cost $21,500,and it is estimated that rehabilitation will cost $800 per lateral.
Contact: Ron Proulx, Public Works Department, City of Orlando
SAN LUIS OBISPO,CA
Voluntary Service Lateral Program
Responsible Agency: City of San Luis Obispo Utilities
Department
Population Served: 44,613
Service Area: 10.7 sq. mi.
Sewer System: 130 mi. of combined sewer
The City of San Luis Obispo was experiencing I/I problems
during their rainy season. At the time, the city treatment plant
was suffering from wastewater flows that would increase from
a daily average of 4.5 MGD to over 30 MGD during wet weather
events, pushing the city's wastewater treatment facility over its
design limit.Aflow monitoring study of the city sewer system was
conducted to identify the extent of I/I and its sources.
Flow monitoring data showed that a residential area served by sewers built between 1930 and 1965 was the major contributor of I/I.
The city then video inspected the sewer mains to determine the locations of the I/I within this area.The inspection phase occurred from
1991-1994 and concluded that service laterals were the main source of the I/I. A small sample of laterals revealed that failures were
mainly due to aging construction materials and failed mortar joints, particularly where laterals were constructed from orangeburg or
clay pipe. Service lateral defects identified included root intrusion, misaligned joints, broken pipes, holes,and missing pipes. Based on
these findings, the city adopted and implemented the Voluntary Sewer Lateral Rehabilitation Program (VSLRP) in 1997.
TheVSLRP was developed to mutually benefit the city and homeowners. Homeowners who participate in the program received free
lateral inspection, construction permits, technical advice, and a rebate of half the cost of the replacement or repair up to $1,000 per
property from the city.The lateral rehabilitation methods used by the city were removal and replacement, the most popular method,
as well as trenchless rehabilitation methods of pipe bursting and lining.
More information athttp://www.ci.san-luis-obispo.ca.us/utilities/vslrp_technical.asp
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Collection System Controls: Service Lateral Rehabilitation
References
Curtis, N. M., and Krustsch, A.H. "Trying on Flow
Reduction for Size." Water Environment Technology. 3 (No.
4): 48.
Curtis, N. M., and Krustsch, A.H. 1995. Sewer Rehabilitation
Using Trenchless Technology on Mainlines and Service
Laterals. Conference proceedings at Water Environment
Federation WEFTEC, Anaheim, CA. October 1993.
EPA. 1985. Demonstration of Service Lateral Testing and
Rehabilitation Techniques. Prepared by C. H. Steketee. EPA
600-2-85-131.
EPA. 1991. Sewer System Infrastructure Analysis and
Rehabilitation. EPA 625-6-91-030.
EPA. 1999. Collection Systems O&M Fact Sheet: Trenchless
Sewer Rehabilitation. EPA 832-F-99-032.
National Association of Sewer Service Companies
(NASSCO). 1996. Manual of Practices - Wastewater
Collection Systems. 2nd ed. Baltimore, MD: NASSCO.
Institute for Research in Construction, National Research
Council Canada. 2002. Construction and Rehabilitation
Costs for Buried Pipe with a Focus on Trenchless Technologies.
Prepared by Jack Q. Zhao and Balvant Rajani. Research
Report No. 101.
Paulson, R. I., et al. 1984. "Attacking Private Infiltration/
Inflow Sources." Public Works. 115 (2):54-59
Roberts, G. C. 1979. "Expediting Sewer Studies." Water
Sewer Work. 126 (No. 2): 52.
Rowe, R., et al. 1995. Data Handling Procedures Expedite
Sewer Evaluation and Repair of Service Laterals. Proceedings
of the National Conference on Sanitary Sewer Overflows,
Washington, DC, April 1995.
Water Environment Federation (WEF). 1999. Control of
Infiltration and Inflow in Private Building Sewer Connections.
Alexandria, VA: WEF.
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
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RIPTION
Manhole Rehabilitation
Overview
Manhole rehabilitation is one of several sewer system
controls that can be implemented as part of an on-going
maintenance or sewer rehabilitation program. Structurally
defective manholes can be a source of significant
infiltration and inflow (I/I) to a sewer system. Manhole
rehabilitation is one way to reduce or eliminate I/I and
preserve sewer system capacity for transporting wastewater.
Manhole rehabilitation can range from spot repairs of
structural components to complete manhole replacement.
A typical manhole and its components are presented in
Figure 1. Descriptions of manhole components and a
summary of common defects are presented in Table 1.
Frame Seal or
Chimney Seal
Cover or Insert
Frame
Joint
Cone
Wall
Bench
Base-
Figure 1. Schematic of a typical manhole
The most common manhole rehabilitation methods are:
chemical grouting, spot repairs, coating systems, and
structural reconstruction (ASCE 1997; NASSCO 1996).
These methods are described in more detail below.
Chemical Grouting
Chemical grouting applications are used to fill and
repair cracks and openings in manhole components,
primarily in the frame, chimney, and cone. There
are variety of grouts available including acrylamide,
acrylate, acrylic, urethane gel, and urethane foam.
The selection of a grout type should be based on
site-specific considerations. A single grout or a
combination of grout types may be used depending on
the manhole's depth. The ideal ambient temperature
for applying grout is about 40 °E Grouts need to be
chemically stable; be resistant to acids, alkalis, and
organics; have controlled reaction times; and have a 15
percent shrinkage control (ASCE 1997). For projects
using a combination of grout types, urethane foam is
typically used in the upper five feet of the manhole,
while urethane gel or acrylamide are used for the
lower section (ASCE 1997). Careful inspection of
the grouting work and dye testing is recommended
to ensure adequate sealing. The effectiveness of this
method depends on soil conditions, groundwater table
elevation, type of grouting mixture applied, pattern
of injection, experience of the grout crew, and project
quality control (ASCE 1997).
Spot Repair
Spot repairs include a variety of activities intended
to restore damaged manhole components to a proper
functional condition that prevents or minimizes I/I.
Spot repairs may include: restoration or overhaul of
specific components, or patch work depending on the
degree of damage and the availability of replacement
parts. The types of manhole I/I that can be addressed
with spot repairs include surface water entering
through holes in the manhole cover and the space
between the manhole cover and frame, and subsurface
water entering from under the manhole frame and
chimney. Damaged manhole covers can be sealed by
replacing them with a new watertight cover; sealing the
existing cover with asphaltic mastic and plugging vent
and pick hole plugs; installing watertight inserts under
the existing manhole cover; or by installing rubber
gaskets. Damaged frame-chimney joint areas can be
sealed internally, without excavation, when frame
alignment and chimney conditions permit.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 1. Summary of manhole components and common defects1.
Component
Bench
Chimney
Cone
Cover
Frame
Description
Concrete or brick floor which
directs incoming flows to the
outlet piping and minimizes
solids buildup. Includes bench/
channel joint.
Narrow vertical section built from
brick or from concrete adjusting
rings that extends from the top
of the cone to the frame and
cover.
Reducing section which tapers
concentrically or eccentrically
from the top wall joint to the
chimney or the frame and cover.
Lid which provides access to the
interior of the manhole.
The cast or ductile ring which
supports the cover.
Typical Defects
Cracked, loose, missing pieces, leaking
channel/bench seal, deteriorated, or
debris/deposition
Cracked, broken, or deteriorated
Cracked, loose, missing mortar, leaking
cone/wall joint, or deteriorated
Open vent or pick holes subject to
ponding, bearing surface worn or
deteriorated, poor fitting, cracked or
broken, or missing
Bearing surface worn or deteriorated,
no gasket for gasketed frames, cracked
or broken, or frame offset from chimney
Defect Result
Infiltration
Infiltration
Infiltration
Inflow
Infiltration and
Inflow
1 ASCE1997
Coating Systems
Coating systems have been used successfully for
manhole rehabilitation for over 20 years. The
application of coating systems to the inner surface
of the manhole protects concrete, steel, masonry,
and fiberglass structures against chemical attack,
abrasion, high temperatures, infiltration, and erosion.
There are numerous coating systems available under
various trade names, but in general they have similar
basic components: rapid set patching, plugging, and
coating compounds. The coating is applied in one or
more layers to the manhole interior either by machine
(spraying) or by hand. Surfaces that need coating
require proper cleaning and preparation. If there
is a potential for the presence of hydrogen sulfide,
corrosion-resistant additives should be included in
the coating mixture. Careful monitoring of cleaning,
preparation, coating, and clean-up is important, as is
testing for effectiveness after rehabilitation, using dye-
water flooding, water exfiltration, or vacuum air testing
Structural Reconstruction
Structural reconstruction is a rehabilitation method
that completely restores the structural integrity
of manhole walls through in-situ reconstruction
methods. Structural reconstruction can be done with
the following: poured-in-place concrete; prefabricated
fiberglass, PVC rib-lock liner, prefabricated reinforced
plastic mortar, spiral wound liner, cured-in-
place structural liners, prefabricated high-density
polyethylene, and spray-applied systems (NASSCO
1996). Selection criteria for using this rehabilitation
method include substantial structural degradation and
life-cycle cost justifications. When completed, the wall
should be a minimum of 36 inches in diameter and
three inches thick. The use of Type II Portland cement
mix and calcium aluminate or other special cement
mixes or linings for corrosion resistance is generally
recommended (ASCE 1997).
Key Considerations
The first step in selecting an appropriate manhole
rehabilitation method is to conduct a thorough inspection
of the manhole and its components. Selection of the
appropriate method depends on several factors including:
• The type of problem to be remediated;
• Physical characteristics of the structure such as
construction material, age, and condition of manhole;;
and
• Location with respect to traffic and accessibility, risk
of damage or injury associated with current condition,
and cost/value in terms of rehabilitation performance
(NASSCO 1996).
CSC-46
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Collection System Controls: Manhole Rehabilitation
Applicability
Selection of an appropriate manhole rehabilitation
technique is based on site-specific conditions. Chemical
grouts are commonly used for rehabilitating manholes
made of brick that are structurally sound. Spot repairs
of manhole components are most appropriate for
addressing minor defects. Coating systems are applicable
for manholes with brick structures that show minimal
or no evidence of movement or subsidence, since the
coatings have minimal shear or tensile strength, and at
sites not conducive to excavation or major reconstruction.
Structural reconstruction is applicable for standard
manhole dimensions (48-72 inches inner diameter) where
substantial structural degradation has occurred. Structural
reconstruction methods tend to be more expensive than
other rehabilitation techniques.
Advantages
The primary advantage of manhole rehabilitation is a
reduction in the capacity demanding I/I entering the sewer
system through damaged manholes. Many municipalities
have successfully implemented manhole rehabilitation
programs as part of larger efforts aimed at reducing I/I and
other extraneous flows into sewer systems. For manholes
experiencing inflow from the surface, repairing or replacing
individual components can be the most efficient and
cost-effective rehabilitation method. For example, rubber
gaskets are inexpensive and can effectively seal the cover
without costly excavation. On a similar note, chemical
grouting which seals cracks and voids along the manhole
walls, is significantly less expensive than applying a coating
system. Structural relining is often the most appropriate
rehabilitation method for severely deteriorated manholes.
An added benefit of structural relining is the renewal of
manhole structural integrity and extended service life of the
entire manhole.
Disadvantages
Manhole rehabilitation methods that require excavation can
be significantly more expensive. For example, replacement
of a manhole frame, rebuilding of a chimney and cone, and
structural relining all require more extensive construction
procedures including pavement replacement and surface
restoration. Structural relining can reduce the diameter
of the manhole and may entail higher initial costs. On
the other hand, spot repairs or chemical grouting do not
improve the structural integrity, and in some cases, may not
be the most cost-effective long-term solution, especially for
older manholes. In addition, the location of the manhole
can entail significant safety risks for the work crew as some
manholes are located in busy intersections and subject to
considerable vehicle traffic.
Cost
The cost of rehabilitating individual manholes varies
depending on the method selected and other site-specific
conditions. A range of average costs for specific methods
along with the anticipated useful life of the rehabilitated
manhole or component are presented in Table 2. Selection
of the most appropriate rehabilitation method often
involves an assessment of cost and cost-effectiveness. If the
amount of I/I controlled through manhole rehabilitation
is known, then the cost of manhole rehabilitation can
be compared directly with the cost of transporting and
treating the I/I. When assessed in this manner, replacing
or sealing of manhole covers is often cost-effective if
substantial I/I enters the sewer system at manhole covers.
However, in some situations, it may be more cost-effective
to conduct a system-wide, comprehensive rehabilitation
instead of assessing the need for repair or replacement of
individual components. In addition to the volume of I/I
removed, other important considerations include life-cycle
cost, risk of failure, damage to surface from unrepaired
manholes, disruption during construction, and life
expectancy.
Table 2. Manhole rehabilitation costs and life expectancies.3
Rehabilitation Method
Seal existing cover
Replace cover
Adjust frame
with excavation
without excavation
Seal frame/applied seal
gasket (applied seal)
manufactured seal
Replace frame
Coating systems
with corrosion
protection
without corrosion
protection
Chemical grouting
Structural lining
Replace manhole
Initial Cost
Range ($)b
20-50
1 20-240
1 50-640
150-200
250-350
250-415
250-415
415-685
500-850
350-650
540-835
1,600-3,500
2,400-5,500
Anticipated
Life (Years)
8
50
50
25
7
7
25
50
15
15
15
50
50
" Based on a standard 9-foot,48-inch diameter manhole (ASCE
1997)
b Costs are in 2002 dollars
CSC-47
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Implementation Examples
PERKASIE
BOROUGH, PA
Manhole Sealing
Responsible Agency: Perkasie Borough The Perkasie Borough Authority provides water and sewer services to Perkasie
Authority Borough and three neighboring communities in southeastern Pennsylvania.Itis
Population Served: 10,000 also one of six municipal members who have their sewage treated at a regional
Service Area: 2.5 sq. mi. sewage treatment plant. In the early 1990s, the regional plant rated at 4 MGD
Sewer System: 33.5 mi. of sanitary sewer was receiving 6-7 MGD of flow during wet weather. Concerned about the I/I,
the Pennsylvania Department of Environmental Protection (DEP) implemented
a moratorium on new sewer connections until I/I was substantially reduced.
Perkasie Borough found that manhole rehabilitation provided a simple, economical,and acceptable means to reduce I/I and get the
moratorium on development lifted.
Perkasie Borough conducted a comprehensive study to determine the extent to which I/I contributed to high flow rates. As part of
the study, flow monitoring was carried out at eight representative locations over a three month period which included extended
dry periods, small to medium storm events, and three storms greater than one inch. The extent of I/I was determined through
comparison of water use data with monitored flow data. Sewersheds were ranked from best to worst and prioritized for corrective
action. A second flow monitoring effort was undertaken to determine the amount of I/I attributable specifically to manholes. Flow
was measured in a sewershed serving 230 homes that had relatively new PVC piping.The flow monitoring showed that most of the
inflow was entering the sewer system through manhole covers, frames, and connecting seals. Further, pilot tests showed that the
installation of new seals would produce dramatic reductions in I/I.The evidence was so persuasive that the Pennsylvania DEP agreed
that for every 3.2 seals installed, one new dwelling unit could be constructed in the service area. Perkasie Borough handles its own
installations, and has found that the average cost-per-manhole is $310 for components and installation. Installation of the seal is an
economical and effective way to reduce I/I and has become a standard procedure for new manholes.
Contact Gary Winton, Perkasie Borough Authority
BROWARD
COUNTY, FL
Manhole Rehabilitation
Responsible Agency: Broward County
Southern Regional Sewer Authority
Population Served: 288,600
Service Area: 106 sq. mi.
Sewer System: 536 mi. of collection sewer
The Broward County Southern
Regional Sewer Authority completed
a comprehensive sewer system
rehabilitation program in 1996. The
rehabilitation program eliminated
approximately 5.64 MGD of extraneous
flow via 429 manholes repairs, 427
sewer line point repairs covering approximately 179,360 linear feet of lined or grouted
main sewer line,and 314 private service lateral repairs.The sewer rehabilitation program
reached its goal of eliminating 35 percent of the total system I/I.The construction cost for
this project was $6.9 million.
Manhole Rehabilitation
Method
Cementitious liner
Realign manhole cover
Install cover inserts
Replace frame and cover
Install fiberglass liner
Number
Completed
333
59
58
32
10
More information at http://www.avantigrout.com/literature/casestudymiamil.pdf
CSC-48
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Collection System Controls: Manhole Rehabilitation
CINCINNATI, OH
Manhole Rehabilitation Project
Responsible Agency: Metropolitan Sewer
District of Greater Cincinnati
Population Served: 800,000
Service Area: 400 sq. mi.
I Sewer System: Over 3,000 mi. of sanitary and
combined sewer
The Metropolitan Sewer District of Greater Cincinnati (MSD-GC) provides
wastewater treatment services to more than 800,000 customers in Hamilton
County, Ohio. Faced with I/I problems, MSD-GC conducted a demonstration
project to evaluate various manhole rehabilitation products as part of a larger
sewer system rehabilitation program. In 2001, over 35 different manhole
rehabilitation products were installed and tested.The knowledge gained from the
demonstration project allowed MSD-GC to develop specifications to maximize the
success of future manhole rehabilitation efforts.These specifications involved the
development of guidelines on substrate preparation, material application,frost-line protection, testing and inspection,and contract
warranty requirements. Manholes requiring rehabilitation of the invert (flow channel) were found to be more costly due to the need
to plug and bypass flows.
Following the demonstration project, MSD-GC launched a project to evaluate the performance and cost of three particular manhole
rehabilitation methods (i.e.,cementitious coatings, spray-on epoxy coatings,and cured-in-place manhole liners).This project will result
in the rehabilitation of 150-300 brick and concrete manholes per year,at an annual cost of approximately $1 million.This project also
allows MSD-GC to test the effectiveness of its current manhole rehabilitation specifications and to make necessary adjustments based
on performance results. Initial post-rehabilitation flow monitoring data indicate improvement as a result of the manhole rehabilitation.
The data show that cementitious coatings and spray-on epoxy are less effective than cured-in-place methods in reducing I/I.
Contact Ralph Johnstone, Metropolitan Sewer District of Greater Cincinnati
References
American Society of Civil Engineers (ASCE). 1997. Manhole
Inspection and Rehabilitation. In Manuals and Reports on
Engineering Practice No. 92. Prepared by the Committee
on Manhole Rehabilitation of the Pipeline Division of the
ASCE. New York, NY: ASCE.
EPA Office of Research and Development, Center for
Environmental Research Information. 1991. Handbook:
Sewer System Infrastructure Analysis and Rehabilitation.
Cincinnati, OH: EPA Office of Research and Development.
EPA/625/6-91/030.
Johnstone, Ralph. Interview by Limno-Tech, Inc., December
2002. Washington, D.C.
Larson, J.P., and C. Garcia-Marquez. 2000. Broward County,
Florida - Successful I/I Rehabilitation Programs. Presented at
the Water Environment Federation WEFTEC Conference,
Anaheim, CA, 2000.
National Association of Sewer Service Companies
(NASSCO). 1996. Manual of Practices: Wastewater Collection
Systems. 2nd ed. Maitland, FL: NASSCO.
Metropolitan Sewer District of Greater Cincinnati (MSD-
GC). "MSD Receives Trenchless Technology Award."
Retrieved December 9, 2002.
http://www.msdgc.org/news/ archives/trenchless_tech_
award/
Winton, Gary. Interview by Limno-Tech, Inc., March 2003.
Washington, D.C.
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
CSC-49
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RIPTION
In-Line Storage
Overview
Many sewer systems experience high flow rates during wet
weather periods. The use of storage facilities to attenuate
and store peak wet weather flows is widely implemented to
reduce or eliminate CSOs and SSOs. In-line or in-system
storage is the term used to describe facilities that depend on
existing, available storage in the sewer system to control wet
weather flows. In-line storage techniques include the use of
flow regulators, in-line tanks or basins, and parallel relief
sewers. Each of these types of in-line storage is described
below.
Flow Regulators
Flow regulators are used to optimize in-line storage
by damming or limiting flow in specific areas of the
sewer system. Flow regulators can be grouped into two
categories: fixed and adjustable.
Fixed regulators, as their name implies, are stationary
and do not adjust to variations in flow. They are ideally
located at key hydraulic control points. With fewer
moving parts and sensors, fixed regulators tend to be
less expensive to install, operate, and maintain than
adjustable regulators. Fixed regulators include:
• Orifices
• Weirs
• Flow throttle valves
* Restricted outlets
• Vortex throttle valves
One specific type of fixed regulator is the vortex
throttle valve shown in Figure 1. Low flows pass
through vortex throttle valves without restriction. Once
the flow reaches a pre-determined level, an air-filled
vortex is automatically created that reduces the area
through which flow can pass, damming the flow behind
the valve (John Meunier/USFilter 2002). The vortex
does not create a constriction. Trash and debris flow
Vortex
throttle
Outfall
Figure 1. Schematic of a vortex throttle.
through the valve easily after excess flows subside (EPA
1993).
Adjustable regulators are more complex and can be
operated in a dynamic mode. Consequently, they offer
a greater potential to maximize the available in-system
storage by reacting to the variable nature of flow in
the sewer system (Moffa 1997). Adjustable regulators
include:
• Inflatable dams
• Reverse-tainter gates
• Float-controlled gates
• Sluice-type gates
• Tilting plate regulators
An example of an adjustable regulator is the inflatable
dam, shown in Figure 2. Inflatable dams are typically
made of rubberized fabric and are inflated and deflated
to control flow. Automatic sensors are often used to
activate the dams. The dams can be filled with air,
-------
Report to Congress on the Impacts and Control ofCSOs and SSOs
Dam
controls
Inflatable dam
Figure 2. Schematic of an inflatable dam system.
water, or a combination of both. Air control is generally
less costly, but water provides better control over dam
shape (EPA 1993). With the dam inflated, flow can be
stored in upstream pipes.
In-Line Storage Tanks or Basins
Storage tanks and basins constructed in-line within the
sewer system can also be used to attenuate and store
flows during wet weather periods. Dry weather flows
pass directly through in-line storage tanks or basins.
Storage within the in-line tanks or basins is typically
governed by a flow regulator which limits flow exiting
the facility during wet weather periods. The primary
function of in-line storage structures is the attenuation
of peak flows, not treatment. Flows exiting the storage
structure are conveyed downstream for treatment.
Therefore, unlike off-line retention basins and deep
tunnel storage facilities, in-line tanks and basins are
rarely equipped with disinfection, and may not have an
outlet to discharge directly to a receiving water.
Parallel Relief Sewers
In-line capacity can also be created by installing relief
sewers parallel to existing sewers, or by replacing older
sewers with larger diameter pipes. The installation of
parallel relief sewers, or larger pipes, is accomplished
in the same manner as installing new pipes - using
traditional open-cut construction methods or
trenchless technologies. Trenchless technologies refer
to several types of construction methods that minimize
the environmental and surface impacts of sewer
installation. More information on these techniques
is provided in the "Sewer Rehabilitation Technology
Description," in Appendix B of the 2003 Report to
Congress on the Impacts and Control ofCSOs and SSOs.
Key Considerations
Applicability
Taking advantage of existing storage within the sewer
system has broad application in CSSs and SSSs. It is
regarded as a cost-effective way to reduce the frequency
and volume of CSOs and SSOs, often without large capital
investments. Maximization of storage in the sewer system
is one of the NMC required of all CSO communities. EPA
guidance describes maximization of storage as "making
relatively simple modifications to the CSS to enable the
system itself to store wet weather flow until downstream
sewers and treatment facilities can handle them" (EPA
1995).
The physical condition of the sewer system must be
considered when examining potential in-line storage. The
amount of storage potentially available in the sewer system
largely depends on the size or capacity of the pipes that will
be used for storage, and the suitability of sites for installing
regulating devices. The trunk sewers and many interceptors
within CSSs are often designed to convey flows 5-10 times
greater than average dry weather flows, and often provide
some potential capacity for storage. Also, areas where the
pipe slope is relatively flat often offer opportunities for
storage.
An important component of successful in-line storage
applications is proper operation and maintenance. By
maintaining the initial condition of the sewer system (i.e.,
not allowing sediment build up within the pipes), the
complete capacity of the sewer is available for storing and
transporting excess wet weather flows. Similarly, CSO and
SSO volumes can be reduced by removing obstructions that
decrease the capacity of the sewer system. Larger objects
often must be removed by hand, whereas sewer flushing can
be used to remove smaller obstructions and sediment build
up (EPA 1999). Additional sewer cleaning techniques are
discussed in the "Sewer Cleaning Technology Description,"
in Appendix B of the 2003 Report to Congress on the Impacts
and Controls ofCSOs and SSOs.
Certain factors limit the applicability of in-line storage; for
example it can increase the possibility of basement backups
and street flooding (EPA 1999). Basement backups occur
when the level of the flow in the sewer is higher than the
level of the connection between the service lateral and
the building basement. Storing flow in existing pipes may
exacerbate this condition because damming devices raise
the level of the flow in the sewer system. Field surveys and
investigations of sewer maps and as-built drawings are
required in order to prevent the throttling back of flows to
a degree that causes flooding and backups.
STR-2
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Storage Facilities: In-Line Storage
Use of in-line storage may also slow flows and allow
sediment and other debris present in wastewater or urban
runoff to settle out in the pipes. If allowed to accumulate,
the sediment and debris can reduce available storage and
conveyance capacity. Therefore, an important design
consideration for in-system storage is to ensure that
minimum flow velocities are provided to flush and transport
solids to the wastewater treatment plant.
Advantages
Advantages of in-line storage include:
• Maximum utilization of existing capacity, which may
reduce size or scope of other controls;
• Development of in-line storage in parallel relief or
upsized sewers can be coupled with other sewer
rehabilitation projects;
• Relatively inexpensive in comparison to other types of
storage;
• Attenuates peak wet weather flows and equalizes loads
to the treatment facility; and
• Reduces frequency and volume of CSOs and SSOs
during light to moderate rainfall events.
Disadvantages
Disadvantages of in-line storage include:
• Provides little treatment of wet weather flows on its
own;
• May be difficult to construct large storage volumes
typically required for complete CSO control; and
• Increased potential for basement backups and street
flooding.
Cost
The largest expenditure for most types of storage facilities
is the construction of the actual storage volume. By taking
advantage of underutilized capacity that may currently exist
within the sewer system, costs are limited to flow regulators
and other equipment needed to optimize the attenuation
and storage of wet weather flows. The costs associated with
construction of in-line storage range from approximately
$0.06 per gallon to more than $1 per gallon. Cost
information from a number of in-line storage applications is
presented in Table 1 and 2.
The cost information shows that per gallon costs of storage
developed using flow regulators are significantly less than
storage developed through the installation of large diameter
or parallel relief sewers.
Table 1. Summary of costs of inflatable dam installed in select communities.
Municipality
Washington, DC
Louisville, KY
Saginaw, Ml
Technology
Inflatable Dam
Inflatable Dam
Flow Control
Chamber with a
Vortex Throttle
Characteristics
•Total Storage = 36 MG
• 2 dams in 8 locations throughout the system
• Fully inflated under low pressure during dry
weather
•Total Storage = 2.5 MG
• Sneads Branch Relief Sewer collects wet weather
flow from 1 1 CSOs
•Total Storage = 1.4MG
Year
Constructed
1990
2001
1986
Cost
Construction Cost:
$2.2 million or
$0.06/gallon
Construction Cost:
$1.07 million or
$0.43/gallon
Construction Cost:
Less than $290,000
or $0.21/gallon
Philadelphia, PA Inflatable Dam
•Total Storage = 16.3MG
• 3 large inflatable dams located in large sewers
11-15 ft. high
• Can inflate in 15 minutes and deflate in 5 minutes
Planned Dam Cost: $650,000
Civil Construction
Cost: $4.2 million
Total Cost:
$4.8 million or
$0.29/gallon
Houston,TX Parallel Relief -Total Storage = ~ 0.64 MG
Sewer " Diameter: 36 in., 18 in.,and 15 in.
• Length: over 6,000 ft.
• Installed parallel to the existing system which was
abandoned in place
• Part of a plan to eliminate overflows from sewer
system
1995 Construction Cost:
$436,126 or
$0.68/gallon
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Table 2. Summary of costs of in-line basins and relief sewers in communities.
Municipality Technology Characteristics
Bangor, ME In-line Basin • In-line storage tunnel
• Made from V-bottom precast box sections
Davis Brooke Storage Facility
Year
Constructed
Total Storage = 1.2MG
Barkersville Storage Facility
Total Storage = 1.4MG
Houston, TX Parallel Relief -Total Storage = ~ 0.64 MG
Sewer • Diameter: 36 in., 18 in., and 15 in.
• Length: over 6,000 ft.
• Installed parallel to the existing system which
was abandoned in place
• Part of a plan to eliminate overflows from
sewer system
Portland,OR Parallel Relief -Total Storage = ~ 42 MG
Sewer • Conveyance pipe that is 6 ft. in diameter and a
storage pipe that is 1 2 ft. in diameter
•Total length is 3.5 mi.
Syracuse,NY In-line Basin -Total Storage = 5 MG
• Erie Boulevard Storage Facility
• Box culvert with sluice gate control
Dimensions: 7.5 ft. wide, 1 0.5 ft. high, and 8,640
ft. long
1 998 Construction Cost:
$1.4 million or
$1.17/gallon
2002 Construction Cost:
$2 million or
$1.43/gallon
1995 Construction Cost:
$436,1 26 or
$0.68/gallon
2000 Design and Construction
Cost: $76 million or
$1.81/gallon
1 970s; Approximate Cost of
refurbished Refurbishment:
2002 $2.6 million or
$0.53/gallon
Implementation Examples
BOSTON, MA
System Optimization Plan
Responsible Agency: Massachusetts
Water Resources Aufnorit
ority
Population Served: 2.5 million
Service Area: 406 sq. mi.; 13 sq. mi. of
combined sewers
Sewer System: 228 mi. of interceptor sewer
The Massachusetts Water Resources Authority (MWRA) provides sewer services
for 43 communities in the Boston metropolitan area. The City of Boston and
three surrounding communities have combined sewer areas. MWRA developed
a system optimization plan in 1993, which included operational modifications
and simple, low-cost structural changes to reduce CSO frequency. Structural
alterations included repairing regulators, raising weir heights, and installing
new weirs and regulators to increase storage within the sewer system. All 103
projects outlined in the system optimization plan have been completed. MWRA has since completed other system evaluations that
have resulted in more simple structural alterations to reduce the occurrence of CSOs. As of 1997, MWRA had spent a total of $3.1
million on structural alterations, which have reduced average annual CSO discharges by 400 MG.The typical capital costs for brick
and mortar weirs, formed concrete weirs, and stop logs are $3,650, $13,525, and $20,315, respectively.
More information at http://www.mwra.state.ma.us/sewer/html/sewcso.htm
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Storage Facilities: In-Line Storage
LOUISVILLE, KY
Responsible Agency: Louisville and Jefferson
County Metropolitan Sewer District
Population Served: 600,000
Service Area: 205 sq. mi.
Sewer System: ~ 2,800 mi. of sewers
Snead Branch Relief Sewer Inflatable Dam
The Sneads Branch Relief Sewer is an 11 foot semi-elliptical tunnel that
was built in 1951 to control flooding. The relief sewer receives no dry
weather flow, which was one of the reasons it was selected for storage of
wet weather events. An inflatable rubber dam was installed to maximize
storage in the relief sewer; minimal tunnel modifications were necessary.
During normal flow conditions,the dam is half inflated. During wet weather
events, it is inflated to full height. A water level sensor just above the dam activates the inflation.The relief sewer captures flow from
11 upstream CSOs,and it can store up to 2.5 MG of combined sewage.lt is predicted that the inflatable dam will reduce the average
annual CSO volume by 63 percent from 43 MG per year to 18 MG peryear.The cost of the Sneads Branch Relief Sewer Inflatable Dam
was $1.07 million or $0.43/gallon of storage.
Contact: Angela Akridge, Louisville and Jefferson Metropolitan Sewer District
PHILADELPHIA, PA
Inflatable Dams
Responsible Agency: Philidelphia Water
Department
Population Served: 2 million
Service Area: 335 sq. mi.
Sewer System: 1,600 mi. of combined
sewers
As part of Philadelphia's effort to control CSOs,the City Water
Department plans to install three inflatable dams in large sewers
that have available in-line storage.The dams will range from 11 to 15
feet high and will be automatically controlled for both dry and wet
weather conditions.The three dams will enable 16.3 MG of flow that
might otherwise discharge to local receiving waters to be stored in
existing sewers, reducing CSO volumes by 650 MG per year.
The first inflatable dam, located in the city's main relief sewer, will
be operational by the end of 2004.The associated civil work projects such as sewer rehabilitation have been completed for this
project. When operating, the dam will have the ability to store up to 4 MG of combined sewage, and it is expected to reduce the
number of CSO discharges to the Schuylkill River from 32 per year to four per year. Another inflatable dam will be installed in
Rock Run during the summer of 2005.The total cost for the installation of the dams and sewer rehabilitation is approximately $4.8
million, or $0.29/gallon of storage.
More information at http://www.forester.net/sw_001 l_innovative.html and http://www.phila.gov/water/index.html
STR-5
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Report to Congress on the Impacts and Control ofCSOs and SSOs
SYRACUSE, NY
Erie Boulevard Storage System
Responsible Agency: Onandaga County
Department of Water Environment
Protection
Population Served: 400,000
Service Area: 13 sq. mi.; 11 sq. mi. of
combined sewer
ewer System: 3,000 mi. of sewer
The Erie Boulevard Storage System was originally constructed in the 1970s as a
separate storm water system.The facility is a box culvert that is 7.5 feet by 10.5
feet and 8,640 feet long. It has a storage volume of 5 MG,and an additional 1 MG
of storage is available in ancillary conveyance pipes. It was retrofitted in 1985
with four sluice gates to facilitate the storage of combined sewage, and reduce
CSO discharges to Onondaga Creek.
The original sluice gate control system was located within underground concrete
vaults. Moisture and road salt severely damaged the control system requiring a facility upgrade.The upgrade was completed in July
2002, and included refurbishment of the sluice gates, construction of an above ground control center, and installation of a real-
time control system. It is estimated that the Erie Boulevard Storage System will now capture 220 MG of wet weather flow annually.
Upgrades to the Erie Boulevard Storage System cost $2.6 million or $0.52/gallon of storage.
More information at http://www.lake.onondaga.ny.us/ol3113.htm
PORTLAND. OR
Parallel Relief Sewers
Responsible Agency: City of Portland
Population Served: 500,000
Service Area: 133 sq. mi.
Sewer System: 2,256 mi. of sewer
In 1972, the City of Portland's CSS was estimated to release 10 BG of CSO
annually into local receiving waters. In 1991, the city started a 20-year
program to curb CSOs to the Willamette River by 94 percent, and to the
Columbia Slough by over 99 percent.The plan includes actions to fully utilize
storage in the existing sewer system by modifying 32 diversion structures.
The city has also invested in the construction of parallel relief sewers to store
combined sewage that would otherwise be discharged to the Columbia Slough. Specifically, the city constructed 3.5 miles of six
foot diameter conveyance pipe and a 12 foot diameter parallel relief sewer. It took three years to construct this relief sewer, which
became operational in September 2000. It captures 100 percent of the overflows from the eight CSO outfalls in its drainage area and
an average of 440 MG of combined sewage per year.The cost of the Columbia Slough Consolidation Conduit was approximately $76
million or $1.81/gallon of storage.
More information at http://www.cleanriverworks.com/
STR-6
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Storage Facilities: In-Line Storage
References
City of Portland, Oregon, Bureau of Environmental
Services. 2002. "Action 4: Upgrading Portland's Eastside
Sewer System." Retrieved October 2, 2002. http://
www.cleanrivers-pdx.org/pdf/action4.pdf
Dahme, J. and J. Sullen. 2000. "Innovative Strategy Helps
Philadelphia Manage Combined Sewer Overflows."
Retrieved October 7, 2002.
http://www.forester.net/sw_001 l_innovative.html
District of Columbia Water and Sewer Authority. 2002.
"Final Report: Combined Sewer System Long Term Control
Plan." Retrieved October 9, 2002.
http://www.dcwasa.com/education/css/
longtermcontrolplan.cfm
EPA Office of Research and Development. 1993. Manual:
Combined Sewer Overflow Control. EPA 625-R-93-007.
EPA Office of Water. 1995. CSO Guidance for Nine
Minimum Controls. EPA-832-B-95-003.
EPA Office of Water. 1999. Combined Sewer Overflow
Technology Fact Sheet: Maximization of In-line Storage. EPA
832-F-99-036.
Gray, W. et al. 1999. Prevention and Control of Sewer System
Overflows: WEF Manual of Practice No. FD-17. Alexandria:
Water Environment Federation.
John Meunier/USFilter. 2002. "CSO/Stormwater
Management: Hydrovex Product Line." Retrieved
December 9, 2002.
http://www.johnmeunier.com/2002/en/products/pdf/
hydrovex_line_card.pdf
Moffa, Peter. 1997. Control and Treatment of Combined
Sewer Overflows. New York: Van Nostrand Reinhold.
Inclusion of this technology description in this Reportto
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
STR-7
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RIPTION
STORAGE FACILITIES
Off-line Storage
Overview
Many sewer systems experience high flow rates during wet
weather periods. The use of storage facilities to store and
attenuate peak wet weather flows is widely implemented
to reduce or eliminate CSOs and SSOs. Off-line storage
is the term used to describe facilities that store or treat
excess wet weather flows in tanks, basins, tunnels, or other
structures located adjacent to the sewer system. During dry
weather, wastewater is passed around, not through, off-line
storage facilities. During wet weather, flows are diverted
from the sewer system to these off-line storage facilities by
gravity drainage or with pumps. The stored wastewater is
temporarily detained in the storage facility and returned
to the sewer system once downstream conveyance and
treatment capacity become available. Most off-line storage
structures provide some treatment through settling, but
their primary function is storage and the attenuation of
peak flows. The use of off-line storage is usually considered
to be a good option where in-line storage is insufficient or
unavailable.
Near-Surface Storage Facilities
Near-surface storage facilities are typically located at
key hydraulic control points. In CSSs, they are often
located near a CSO outfall; in SSSs, they are often
situated in areas where inflow and infiltration (I/I)
problems are severe and difficult to otherwise control.
A typical near-surface storage facility is a closed
concrete structure with a simple design that is built at
or near grade alongside a major interceptor. As shown
in Figure 1, the basic components of near-surface
storage facilities are:
• Basin or tank
• Flow regulating device to divert wet weather flows
to the basin or tank
• Flow regulating device or pumps to drain the basin
or tank
• Emergency relief or overflow point
Near-surface storage facilities in CSSs are sometimes
designed for both storage and treatment. When
designed and operated for these purposes, they can
provide primary treatment or its equivalent including
primary clarification, capture of solids and floatables,
and disinfection of effluent, where necessary, to meet
water quality standards (EPA 1994). Consequently,
screens and disinfection equipment are sometimes
added to those near-surface storage facilities designed
to discharge directly to receiving waters.
Flow-Through
Interceptor
Near-Surface
Storage Basin
T
Emergency
Relief
Figure 1. Basic components of near-surface storage facility.
An illustration of a more complex near-surface storage
facility with multiple tanks that is designed to provide
both storage and treatment is presented in Figure 2. As
shown, screens are employed to remove floatables and
coarse solids, and flows receive disinfection prior to
discharge. Multiple tanks are used to enhance pollutant
removal and facilitate maintenance activities. The
benefits of using multiple tanks include:
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Report to Congress on the Impacts and Control ofCSOs and SSOs
• The "first flush" of pollutants can be retained in
one or more of the tanks long enough to settle
suspended solids, BOD, and nutrients, while the
remainder of the flow is handled in subsequent
compartments
• Allows portions of the facility to remain in service
while maintenance is performed on other portions
of the facility. The number of compartments
used can vary from storm-to-storm according
to the volume of excess wet weather flow
generated, potentially reducing the area requiring
maintenance after smaller storms, which in turn
reduces costs
In a multiple tank configuration, excess wet weather
flows can either pass through each compartment
sequentially (i.e., the flow proceeds through chamber
one, followed by chamber two, and then chamber
three) or through each compartment simultaneously
(i.e., there is flow in compartments one, two, and three
at the same time). Both operational strategies are
illustrated in Figure 2. However, near-surface storage
facilities with multiple compartments are typically
operated in a sequential manner. Specific advantages of
sequential operation include:
• Tanks are only filled as the capacity of a preceding
tank is exceeded; and
. Only that flow reaching the final tank is
disinfected, saving on chemical costs.
Excess Flow
from Sewers
Sequential Flow Pattern
Simultaneous Flow
Disinfected
Flow to
Receiving
Stream
Figure 2. Flow paths for sequential and simultaneous
storage facilities.
Deep Tunnels
Deep tunnel storage facilities are typically used where
large storage volumes are required and opportunities
for near-surface storage are unavailable. Deep tunnels
are primarily implemented as controls in CSSs, but
have had some application in SSSs. As their name
implies, deep tunnels are typically located 100-400 feet
below ground. Tunnel diameters range from 10-50 feet,
and many are several miles in length. Construction
usually requires large tunnel boring machines. Most
deep tunnels are built in hard rock, but some have
been built in unconsolidated material. Lining the
tunnel with concrete or other impermeable material
to prevent infiltration and exfiltration is required in
unconsolidated material, and is recommended for hard
rock. Like near-surface storage facilities, stored flow is
typically conveyed from deep tunnels to a wastewater
treatment plant (WWTP) after wet weather events, as
capacity becomes available.
An illustration of a deep tunnel, as constructed in
Milwaukee, WI, is presented in Figure 3. The basic
components of deep tunnels include:
• Storage tunnel;
• Flow regulating devices to divert wet weather flows
to the tunnel;
• Coarse screening to protect tunnel facilities from
large debris;
• Vertical drop shafts to convey wet weather flows to
the tunnel;
• Pumps to drain and de-water the tunnel;
• Vent shafts to balance air pressure in the tunnel;
• Access shafts that give maintenance personnel
access to the tunnel;
• Solids removal system for areas where grit may
accumulate; and
• Odor control system, if necessary.
Separate Sewer
System
Combined Sewer
System
WWTP
Figure 3. Deep tunnel storage (MMSD 2001).
STR-10
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Storage Facilities: Off-line Storage
Key Considerations
Applicability
Near-Surface Storage Facilities
Near-surface storage facilities have broad applicability
and can be adapted to many different site-specific
conditions by changing the basin size (volume), layout,
proximity to the ground surface, inlet or outlet type,
and, where required, disinfection mechanism. They are
particularly applicable in areas where land is readily
available and the disruption, due to construction, will
be minimal. The adaptability of near-surface storage
facilities has led to their use throughout the country. The
flexibility of the basin design makes near-surface storage
facilities practical for utilities, both large or small, in all
climates.
Deep Tunnels
Deep tunnels provide an alternative to near-surface
storage facilities where space constraints, potential
construction impacts, and other issues make
constructing near-surface facilities challenging. Deep
tunnels can be constructed in a variety of mediums,
but geotechnical exploration is needed to assess the
suitability of subsurface conditions.
The major construction concerns are the structural
integrity of the tunnel, infiltration of groundwater,
and exfiltration of the stored flows. Tunneling in hard
rock tends to be more economical because such tunnels
need minimal, temporary, or permanent structural
supports. Hard rock tunnels also require less lining to
prevent infiltration and exfiltration (NBC 1998). When
tunneling in soft rock or soil, the tunneling equipment is
more expensive. Special equipment is needed to support
the tunnel during construction to prevent the ground
from collapsing. In addition, the cost of lining the tunnel
can be greater because the lining is used to maintain the
shape of the tunnel as well as to prevent infiltration.
Advantages
Near-Surface Storage Facilities
Advantages of near-surface storage facilities include:
• Structural design is simple compared to tunnels and
supplemental treatment facilities;
• Construction and O&M costs are favorable relative
to other structural approaches such as sewer
separation (EPA 1999);
• Operation and response to intermittent and
unpredictable wet weather events is automatic to a
certain extent;
• Operators are allowed the flexibility of returning
the stored wastewater flow to the treatment facility
where it can receive full treatment; maximizing
utilization of existing treatment facilities;
• Helps equalize the delivery of pollutants to the
treatment plant, which tends to improve effluent
quality at the treatment facility as well as treatment
efficiency;
• Treatment of excess wet weather flows consistent
with the CSO Control Policy can be achieved in
CSSs; and
• Aesthetic benefits and other locally defined
objectives can be realized with imaginative design.
For example, Wayne County, MI, constructed two
covered near-surface storage facilities that were
landscaped with recreation facilities including
soccer fields and basketball courts (Wayne County
2000).
Deep Tunnels
Advantages of deep tunnel storage include:
• Large volumes can be stored and transported while
having a minimal effect on the existing surface
features (EPA 1993);
• Disruptions that occur with the open-cut
excavations associated with near-surface storage
facilities can be avoided (EPA 1993); and
• Valuable surface land area is saved by building deep
under the ground's surface.
Disadvantages
Near-Surface Storage Facilities
Disadvantages of near-surface storage facilities include:
• Costs can be substantial relative to non-structural
controls such as I/I reduction;
• Land required for basins and tanks is often located
in premium waterfront locations ;
• Construction activities are disruptive;
• On-going maintenance with attendant costs is
required to keep facilities operating; and
• Solids and captured floatables must be removed and
properly disposed to maintain storage capacity.
Deep Tunnels
Disadvantages of deep tunnel storage include:
• Difficult to map subsurface;
• Budget overruns can occur when boring does not
proceed as planned;
• Tunnels may require substantial, on-going
maintenance activities, including the disposal of
built-up sediment deposits;
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Exfiltration from deep tunnels has the potential
to adversely affect the quality of groundwater in
adjacent aquifers; and
Construction schedules for deep tunnels may be
lengthy, allowing considerable time to pass between
the initial investment and any measured water
quality improvements.
Table.1. Deep tunnel costs from select communities.
Cost
The costs associated with construction of off-line storage
facilities range from less than $0.10 per gallon to $4.61 per
gallon. In general, costs for near-surface storage facilities were
considerably less than those for deep tunnels. The average
cost for deep tunnels was $2.82 per gallon, while the average
cost for near-surface storage was $1.75 per gallon. Tables 1
and 2 present cost information for near-surface and deep
tunnel storage facilities, respectively.
1 Municipality
Washington, DC
Atlanta, GA
Chicago, IL
Rochester, NY
Providence, Rl
Facility Name
Intrenchment
Creek
TARP Project
Milwaukee,WI
1 All costs are in 2002 dollars.
Facility Characteristics
Total Storage = 194MG
3 deep rock tunnels
Total Storage = 34 MG
26 ft. diameter
9,293 ft. long
Total Storage = 2.3 BG
109 mi. of deep rock tunnels
1 50-350 ft. below ground
Total Storage = 175MG
Total Storage = 56 MG
200-300 ft. below ground
26ft. in diameter
13,500 ft long
Total Storage = 405 MG
Depth up to 325 ft.
Year Initiated
To be constructed
1985
1976 (Near
completion)
1993
2001 (Under
construction)
1994
Construction Cost1
$761 million or
$3.92/gallon
$42.2 million or
$1.24/gallon
$2.51 billion or
$1.09/gallon
$690 million or
$3.94/gallon
$258 million or
$4.61/gallon
$866 million or
$2.13/gallon
Table 2. Near-surface storage costs from select communities.
1 Municipality
Atlanta, GA
Chicago, IL
Bangor, ME
Birmingham, Ml
Grand Rapids, Ml
Fairport Harbor,
OH
Seattle,WA
Richmond, VA
Facility Name
McDaniel CSO
Facility
TARP Project
Market Avenue
Retention Basin
Shockoe Basin
Facility Characteristics
Underground basin
Total Storage = 2 MG
Three retention basins
Total Storage = 15.7 BG
Made from pre-cast concrete
sections
Total Storage = 1.2MG
Two compartment retention basin
Flow is simultaneous
Total Storage = 5.5 MG
Three compartment
retention basin; flow is sequential
Total Storage = 30.5 MG
Old oil tank converted for wet
weather storage
Total Storage = 3.2 MG
Total Storage = 1.6MG
Covered and uncovered retention
basin
Total Storage=41 MG
Year Initiated
1986
1976 (Under
construction)
2000
1997
1992
1994
1984
-1988
Construction Cost1 1
$9.2 million or
$1.53/gallon
$1.11 billion or
$0.07/gallon
$2.5 million or
$2.08/gallon
$14.4 million or
$2.61/gallon
$39 million or
$1.24/gallon
$3.1 million or
$0.97/gallon
$6.1 million or
$3.80/gallon
$70 million or
$1.73/gallon
1 All costs are in 2002 dollars.
STR-12
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Storage Facilities: Off-line Storage
Implementation Examples
CHICAGO, IL
Tunnel and Reservoir Plan (TARP)
Responsible Agency: Metropolitan Water
Reclamation District of Greater Chicago Construction of Chicago's Tunnel and Reservoir Plan (TARP) began in 1976. The
TARP contains both deep tunnels and a system of three large reservoirs that act
Population Served: 5.1 million , , .... _„__, , _.
as near-surface storage facilities.TARP has been implemented in two phases.The
Service Area: 873 sq. mi. fjrst phase focused on reducing CSOs. The second phase provides flood control
Sewer System: 4,300 total miles of sewer benefits as well as further increases CSO capture. When completed, the TARP
will have 18 BG of total storage between the three reservoirs and multiple deep
tunnels.The three reservoirs hold 15.7 BG;the plan also includes 109 miles of deep
rock tunnels, located 150-350 feet beneath the ground surface. One reservoir is
located on the site of an abandoned quarry.This siting reduces the amount of excavation needed for the reservoir, but does not
eliminate it.The tunnels are lined to prevent infiltration and exfiltration. Pumping and treating the total volume stored in the TARP
facilities will take two to three days. Since construction started, water quality in the Chicago area receiving waters has improved.
Mass loadings of BOD5,TSS,and volatile suspended solids have dropped by 13,62,and 60 percent, respectively. Once the system is
completed, tunnels in 2006 and reservoirs in 2014, it is believed that further water quality improvements will be observed.The total
predicted cost of TARP is $3.62 billion.The cost of the reservoirs is $1.11 billion or $0.07/gallon.The deep tunnels when completed ,
will cost $2.51 billion or $1.09/gallon.
More information at http://www.mwrdgc.dst.il.us/plants/tarp.htm
ATLANTA, GA
Near-Surface Storage Facilities and Tunnels
Responsible Agency: City of Atlanta
Department of Public Works
Population Served: 1.5 million
Service Area: 260 sq. mi.
Sewer System: 230 mi. of combined sewer
and 1,970 mi. of separate sewer
Twenty percent of Atlanta's sewershed is composed of combined sewers, which
includes the most highly developed area of downtown Atlanta.The city started to
control CSOs in the mid-1980s, using a mix of near-surface storage facilities, deep
tunnels, and sewer separation projects. The Intrenchment Creek Tunnel, which
has a diameter of 26 feet and is 1.76 miles long, can store 30-34 MG of excess wet
weather flows. It can be de-watered in one to two days, by sending the stored
flows for physical and chemical treatment at the associated Intrenchment Creek
Treatment Facility. During a study performed from August 1999 to January 2000,fecal
coliform levels in the effluent from the Intrenchment Creek Facility were below the water quality standard that requires a geometric
mean of 1,000 MPN col/100 ml.
The city also maintains one near-surface storage facility at the McDaniel CSO Facility.This near-surface storage basin holds 2 MG of
combined sewage.The combination of tunnel and near-surface storage creates a total storage volume of 36 MG.This storage has
reduced the frequency of CSO events from 50-60 times per year to approximately 17 per year.The Intrenchment Creek CSO project
cost was approximately $42.2 million or $1.24/gallon.The McDaniel CSO Facility was constructed for $9.2 million or $1.53/gallon.
More information athttp:/www.atlantapublicworks.org
STR-13
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Report to Congress on the Impacts and Control ofCSOs and SSOs
PROVIDENCE, Rl
Deep Tunnel Storage
Responsible Agency: Narrangasett Bay
Commission The Combined Sewer Overflow Abatement Program being implemented by
Population Served- 360 000 tne Narragansett Bay Commission will reduce the frequency of CSO events
_ ... , 10 .' from 71 to four per year. The plan includes sewer separation projects as well
as construction of storage and treatment facilities.The project is divided into
Sewer System: 89 mi. of interceptor sewer three phases Jhe majn component of the first phase js a deep tunne| The
tunnel is 27 feet in diameter, 200-300 feet below the ground surface, and
2.5 miles long. The tunnel's storage volume is 56 MG, and it is designed to
be de-watered within 24 hours. Phase I is expected to reduce CSO volume by 40
percent; the entire project is expected to reduce CSOs by 98 percent. Construction of Phase I started in 2002 and will be completed
in 2009. Phase I will be followed by a two-year monitoring period to assess improvements in water quality as a result of the tunnel.
The final completion date of the entire project is contingent on the success of Phase I.It is anticipated that the reduction in CSOs to
Narragansett Bay will contribute to reductions in shellfish bed closures.The estimated construction cost for the deep tunnel is over
$258 million or $4.61/gallon.
More information athttp://www.narrabay.com/CSO.asp
BANGOR, ME
Kenduskeog East CSO Storage Facility
Responsible Agency: City of Bangor Sewer
Division
Population Served: 33,000
Service Area: 6.4 sq. mi.
Sewer System: 33.21 mi. of sewer, 30 percent
combined
Bangorbegan developmentofa CSO long-term control plan in 1992.Initially,
the city separated a portion of its sewer system. The sewer separation
projects were followed by the installation of three storage facilities,
including the Kenduskeag East CSO Storage Facility. The 1.2 MG near-
surface storage facility is located underneath an existing public parking lot.
Stored flows are released back into the sewer system for treatment at the
WWTP. The basin has a small on-line portion through which dry weather
flows pass everyday. During a wet weather event, when levels rise to 3.5 feet in
the on-line portion of the basin, wastewater spills over into the off-line portion.The off-line portion is comprised of five box section
rows that are 360 feet long and 8 feet wide.The basin's flushing system utilizes stored flow to create waves that clean settled solids
from the bottom of each section.The wastewater level in the basin is monitored electronically, and if the basin reaches capacity, the
monitoring system opens control gates that allow for a controlled and measured CSO event.The construction cost of the storage tank
was $2.3 million or $1.92/gallon.
More information at http://www.precast.org/pages/Solutions/Summer_2002/overflow_in_bangor.html
STR-14
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Storage Facilities: Off-line Storage
GRAND RAPIDS. Ml
Market Ave. Near-Surface Storage Facility
Responsible Agency: Grand Rapids Public Works
Population Served: 261,000
Service Area: 750 sq. mi., 3.9 sq. mi. is combined
Sewer System: 850 mi. of sewer
The Grand Rapids wastewater service area includes the city of Grand
Rapids and six other surrounding towns. The CSS area is small and
consists of only a half percent of the entire service area. In the early
1990s,the city created a plan to deal with the excess wet weather flows
from this area. Part of this plan was the Market Avenue near-surface
storage facility. The design included a multi-stage basin with treatment
facilities to control the 10-year,one-hour storm.The 30.5 MG basin has three compartments which are operated sequentially.The first
compartment allows for primary settling and grit removal. Once this compartment is full,the second compartment begins to fill.The
bottom of the second compartment is equipped with a floor wash system. If the second compartment reaches its capacity, the excess
flow spills over into the third compartment where sodium hypochlorite is added for disinfection.The third compartment discharges
the partially treated and disinfected flow to the Grand River.The near-surface storage facility came on-line in 1992. Since this time,
there has been a noticeable decline in fecal coliform levels in the Grand River.Asan example,in 1989,the annual geometric mean for
fecal coliform was 500 MPN/100 mL,and in 1996,the value was 75 MPN/100 mL.The city believes the reduction can be attributed to
the 90 percent reduction in discharges of untreated CSOs.The construction cost for the Market Avenue near-surface storage facility
was $39 million or $1.24/gallon. Operation and maintenance costs a re approximately $40,000/year or $0.001/gallon.
More information at http://www.epa.gov/owm/mtb/csoretba.pdf
FAIRPORT HARBOR. OH
Responsible Agency: Lake County Regional Sewer District
Population Served: 3,180
Service Area: Not available
Sewer System: Separate sewer system
Converted Surface Storage Facility
Fairport Harbor Village is a historic town located on
Lake Erie in Ohio. The separate sewer system that serves
the city receives considerable I/I, which can be linked
to the system's aged clay pipes. In 1994, engineering
investigations determined that 1.8 MG of storage was
needed to contain the wet weather flows associated with
a five-year design storm event.The original proposal to build a near-surface storage facility near a major overflow point was rejected
largely on the basis of citizen complaints. An alternative industrial site with an aging oil storage tank built in the 1940s was viewed
more favorably,and had the potential to provide 3.2 MG of storage. Further investigations demonstrated the feasibility of converting
the oil tank into an off-line storage tank. It was also found that even with extensive rehabilitation, the tank would provide a savings
of $170,000-$500,000 when compared to the construction of a new facility. Rehabilitation of the oil tank included the removal of
lead-based paint, asbestos-covered exterior piping, crude oil sludge, and interior pipes. A majority of the vertical and horizontal
welds were replaced to meet current standards. In addition to rehabilitation of the tank,a new 5 MGD pump station and a one mile
long force main were installed to convey flows to the tank.The cost of the Fairport Harbor storage facility was $3.1 million or $0.97/
gallon.
Contact: Phillip Shrout,CT Consultants
STR-15
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Report to Congress on the Impacts and Control ofCSOs and SSOs
References
EPA Office of Research and Development. 1993. Manual:
Combined Sewer Overflow Control. EPA 625-R-93-007.
EPA Office of Water. 1994. Combined Sewer Overflow (CSO)
Control Policy. EPA-830-B-94-001.
EPA Office of Water. 1999. Combined Sewer Overflow
Technology Fact Sheet - Retention Basins. EPA-832-F-99-042.
http://www.epa.gov/owm/mtb/csoretba.pdf
Gray, W. et al. 1999. Prevention and Control of Sewer System
Overflows: WEF Manual of Practice No. FD-17. Alexandria:
Water Environment Federation.
Milwaukee Metropolitan Sewerage District. "Sewer
Operations Under Different Weather Conditions." Retrieved
September 20, 2002.
http://www.mmsd.com/deeptunnel/sewersystem.asp
Narragansett Bay Commission. 1998. Combined Sewer
Overflow Abatement Program Concept Design Report
Amendment. Providence, RI: Narragansett Bay Commission.
Wayne County Department of Environment. "CSO
Demonstration Projects." Retrieved September 17, 2002.
http://rougerivercom.readyhosting.com/cso/projects.html
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
STR-16
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RIPTION
STOR,
On-Site Storage
Overview
Many sewer systems experience high flow rates during wet
weather periods. The use of storage facilities to attenuate
and store peak wet weather flows is widely implemented to
reduce or eliminate CSOs and SSOs. On-site storage, that
is storage developed at the wastewater treatment facility, is
often an effective control for managing excess wet weather
flows in systems where sewer system conveyance capacity
exceeds that of the treatment plant.
The two most common forms of on-site storage are flow
equalization basins (FEBs) and converted abandoned
treatment facilities. Flow equalization is used to overcome
operational problems caused by flow rate variations, to
improve the performance of downstream processes, and to
reduce the size and cost of downstream facilities (Metcalf
& Eddy 2003). FEBs are typically located downstream of
screening and grit removal facilities, but they can be placed
just before the headworks of the treatment plant. FEBs
can be configured in two general ways. The FEE can be
placed within the flow path, meaning that all flow reaching
the treatment plant passes through the basin, or it can be
placed outside the flow path, where wet weather flows that
exceed plant design capacity are diverted into the basin.
Both configurations are shown in Figure 1.
On-site storage capabilities may also be developed in
abandoned treatment facilities such as: old clarifiers that
have since been replaced; treatment lagoons or polishing
ponds no longer needed after the construction of more
modern treatment facilities; or pretreatment facilities at
industrial sites near the treatment plant. Storing flows
in abandoned facilities may require modification of the
current wastewater flow path; a flow control device and
piping may be needed to transport flows to and from the
storage facility. It may be possible to retrofit existing piping
for this purpose, otherwise new piping and a pump, if
needed, will have to be installed.
Entering
Flow
Entering
Flow
Remaining
Process
Equalization
Basin
(B)
Pump
Station
Figure 1. Alternative locations for flow equalization basins
(Metcalf & Eddy 2003).
There are three primary design considerations related to
on-site storage facilities: sizing and locating the facility,
handling settled solids, and pumping systems to return
stored flows for treatment. The best location for an on-
site storage facility will vary with the characteristics of the
sewer system, the wastewater, and the type of treatment
required (Metcalf & Eddy 2003). The size of the storage
facility will depend on the wet weather volume it is
designed to hold, and the amount of land available at the
treatment plant for construction, if needed.
On-site storage facilities must be designed to handle the
solids present in the wastewater. For example, in Oklahoma
the state design standards require storage facilities to
be constructed with a minimum of two compartments
(OKDEQ 2002). One compartment, which is lined with
concrete or asphalt, is where the solids are allowed to
settle. The other compartment holds overflow from the
first, during moderate or large wet weather events. The
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Report to Congress on the Impacts and Control ofCSOs and SSOs
settled solids are washed back into the headworks of the
treatment plant, allowing them to receive full treatment.
Other facilities utilize mixing to prevent the deposition of
solids. Mixing equipment requirements can be minimized
by constructing on-site storage downstream of grit removal
facilities. Examples of effective mixing mechanisms for
storage facilities include tipping weirs and flushing gates.
Aeration systems may be necessary if storage basins are
susceptible to becoming oxygen-deprived and septic.
Variable or constant speed pumps may be used to return
stored flows to the treatment plant. A constant speed
pump will return flows at the same speed independent of
the volume of flow stored, whereas a variable speed pump
can be adjusted depending on the stored volume. A flow-
measuring device should be installed to monitor the return
of the stored flow.
While the volume of an on-site storage facility can be very
large, there will be occasions when wet weather flows will
exceed storage capacity. A mechanism to discharge flows
that exceed facility capacity, with or without treatment,
must be available.
Key Considerations
Applicability
On-site storage at the wastewater treatment plant can be
a viable alternative for reducing or eliminating CSOs and
SSOs. There are a number of important considerations
that must be evaluated to determine the applicability of
on-site storage at a given wastewater treatment plant. These
include:
• Maximum flow that can be conveyed to the treatment
plant;
• Maximum flow that can be treated with the existing
treatment processes;
• Availability of land on site for the construction of a
new FEE;and
• Location and volume of abandoned treatment facilities.
Advantages
On-site storage can play an important role in improving
wet weather treatment plant operations. It provides
operators with the ability to manage and store excess flows,
which helps maintain treatment efficiency and ensures that
all flows reaching the plant receive the maximum treatment
possible. Development of on-site storage can also facilitate
operation and maintenance activities. If problems occur at
on-site facilities, it is likely that they will be detected earlier,
and that many of the tools required to make the needed
repairs will already be at the treatment plant.
Constructing storage outside the bounds of the wastewater
treatment plant typically requires an environmental site
assessment. Site assessments are less likely to be required for
on-site storage facilities because the storage is being placed
in a location that has already been approved for such use.
If an assessment is needed, the requirements may be less
rigorous since environmental conditions at the wastewater
treatment plant are known and may have already been
investigated.
Disadvantages
There are limitations to on-site storage that must also be
considered. Development of a large FEE uses space that
might be needed for future plant expansion. Restored
facilities, because of their age, may deteriorate faster than
a new facility. The conveyance system or plant headworks
may limit the amount of wet weather flow that can be
brought to the treatment plant. The headworks can be
expanded, but it can be costly to expand the conveyance
system capacity. Finally, as with any storage facility, on-site
storage has finite capacity which may not be sufficient to
prevent CSOs and SSOs during extreme wet weather events.
Cost
The costs associated with the development of on-site
storage facilities range from as little as $0.01 per gallon to
more than $1.00 per gallon. These costs are, on average,
considerably lower than the construction costs for typical
near-surface storage facilities built outside the bounds
of the treatment plant. Much of the cost savings derives
from being able to site the storage facilities on land already
owned by the utility. The following table presents cost
information from a number of on-site storage applications.
STR-18
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Storage Facilities: On-site Storage
Table. 1. Summary of on-site storage costs.
Municipality
Auburn, NY
Barlesville,OK
Cleveland, OH
Covington, LA
ldabel,OK
Lafayette, LA
Oakland, ME
South Paris, ME
Tulsa,OK
Vinita,OK
Technology
Restored Storage
Flow Equalization
Basin
Restored Storage
Flow Equalization
Basin
Flow Equalization
Basin
Flow Equalization
Basin
Restored Storage
Restored Storage
Flow Equalization
Basin
Holding Ponds
Characteristics
Total Storage = 0.2 MG
Cleaned annually
Total Storage = 20 MG
Sewer system also
includes two other FEBs
Total Storage = 6 MG
Converted ImhoffTanks
Total Storage = 6 MG
Cleaned annually
Total Storage = 10MG
EastWTTP:
Total Storage = 3 MG
WestWTTP:
Total Storage = 3.5 MG
Total Storage = 0.2 MG
FEB from a closed textile
mill
Total Storage = 1.5MG
Clarifiers from old
tannery
Total Storage = 13MG
Total Storage = 7MG
Two holding ponds with
capacity of 3.5 MG each
Year
Initiated
1997
1986
1985
1997
1999
1999
1999
1998
1995
1994
1996
Approximate
Construction Cost1
$930,000 or
$4.65/gallon
$1.70 million or
$0.08/gallon
$18.3 million or
$3.05/gallon
$1.22 million or
$0.20/gallon
$450,000 or
$0.05/gallon
$1.6 million or
$0.53/gallon
$1.9 million or
$0.54/gallon
$27,610 or
$0.14/gallons
Annual Debt Service:
$11 0,000 or
$0.07/gallon
$3.81 million or
$0.35/gallon
$94,000 or
$0.01/gallon
1 All costs aren in 2002 dollars.
2 South Paris, ME, reported negligible construction costs associated with restoring their abandoned on-site facilities. The cost numbers
presented reflect annual operation and maintenence for the facilities.
3 Vinita, OK, approximate construction cost does not include land or other facility improvement costs.
STR-19
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Implementation Examples
AUBURN. NY
Reusing Primary Treatment Facilities
Responsible Agency: City of Auburn
Department of Municipal Utilities In 1993, the City of Auburn began efforts to control both their CSOs and I/I within
Population Served: 35,000 the separate sewer portion of their system.This included the conversion of primary
Service Area: Not Available settling tanks, originally built in the 1930s, into storage for wet weather events.When
Sewer System- Not Available wet weatner f°ws exceed the treatment plant's 25 MGD capacity, excess influent is
directed to the settling tanks. Four tanks, with a combined capacity of approximately
158,000 gallons, serve as storage. When the capacity of the storage tanks is fully
utilized,two additional tanks are used to provide high-rate disinfection and dechlorination before flows are discharged.
To modify the tanks, the primary sludge collectors were removed. A flushing system was then installed to wash the system after a wet
weather event. Weirs were installed to permit flow between the tanks. Odors associated with the facility a re minimized by returning
the entire stored volume to the treatment plant within 24 hours of the wet weather event. Annually, the retrofitted primary settling
tanks capture 5.8 MG of excess flow.The facility captures 76 percent of the possible overflows, which are returned to the plant for full
treatment; the volume that does overflow receives primary treatment and disinfection.The conversion of the primary settling tanks
into wet weather storage facilities cost $930,000 or $4.65/gallon.
Contact: Frank DeOrio, City of Auburn
CLEVELAND, OH
Reusing ImhoffTonks
:
Responsible Agency: Northeast Ohio Regional
Sewer District (NEORSD)
Population Served: 500,000
Service Area: 355 sq. mi.
Sewer System: Not Available
In order to reduce CSO discharges, NEORSD refurbished old Imhoff tanks
located at the Westerly wastewater treatment plant to store combined
sewage. The Imhoff tanks required reconfiguration for CSO storage;. In
addition, sludge removal equipment, bar screens, flow control gates,
and an effluent conduit and pump were installed. The tanks can store
approximately 6 MG and the related interceptor can hold an additional 6
MG,fora total storage of approximately 12 MG.Volumes which exceed the
storage capacity are disinfected and then discharged.The conversion of the tanks was completed in 1985.The storage at the Westerly
plant has helped reduce CSO discharges to the Edgewater State Park swimming beach on Lake Erie.The conversion of the Imhoff
tanks into CSO storage facilities cost $18.3 million or $1.53/gallon.
Contact: Frank Greenland, Northeast Ohio Regional Sewer District
STR-20
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Storage Facilities: On-site Storage
LAFAYETTE, LA
Flow Equalization Basins
Responsible Agency: Lafeyette Utilities System
Population Served: 37,500 'n tne mid 1990s, the Lafayette Consolidated Government started to look at
Service Area- 38 sq mi inflow and infiltration (I/I) problems prevalent in their sanitary sewer system.
, After surveying, rehabilitating, and maximizing flow to the treatment plants,
Sewer System: 650 mi. of separate sewer . ' , .
the Utilities decided to construct FEBs at their East and South wastewater
treatment plants. The FEBs were constructed as part of a larger project that
* included other plant upgrades. The East and South wastewater treatment
plants'FEBscan hold SMGand 3.5 MG, respectively.When flows exceed the maximum flow rate which can be handled by the plant,a
portion of the flow is diverted to the FEB,to protect the treatment processes. Once the wet weather flows subside,the plants continue
to operate at maximum capacity while the basins are drained. Emptying the FEBs can take one to three days. Since the FEBs have
been in operation, hydraulic overload violations have been reduced from an average of six to nine annually to zero.The estimated
cost for the East FEB was $1.6 million or $0.53/gallon.The estimated cost for the South FEB was $1.9 million or $0.54/gallon.
More information athttp://www.lus.org/site.php?pagelD=2
>AKLAND.ME
Restored Flow Equalization Basin
Responsible Agency: Oakland Public Works
Population Served: 6,000
Service Area: Not Available
Sewer System: 7 mi. of sewer
Oakland's sewer system consists mainly of combined sewers. The city has
been implementing CSO controls since 1997.These efforts include separating
a portion of the combined sewer system and other targeted inflow reduction
activities. As a result, Oakland has been able to eliminate both of its CSO
outfalls and transport all remaining wet weather flows to its wastewater
treatment plant. Although the city had sufficient sewer system capacity to
transport these wet weather flows, it did not have treatment facilities capable of handling the peak wet weather flow.The city was
able to utilize an FEB installed at the treatment plant for a nearby textile mill that had since ceased operation.The FEB was built in
1990 by the textile mill as part of their pretreatment program, but had sat unused since the mill closed shortly afterwards. Oakland is
able to store 0.2 MG of excess wet weather flows in the basin,and then bleed it back to the wastewater plant for treatment as capacity
becomes available.The FEB is available to the city year-round, but is mainly used during spring snow melts.To bring the FEB back into
operation will cost approximately $27,610 or $0.14/gallon; operational costs are minimal.
Contact: Jim Fitch, Woodardand Curran
STR-21
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Report to Congress on the Impacts and Control ofCSOs and SSOs
SOUTH PARIS. ME
Clarifiers from Old Tannery Storage
Responsible Agency: Paris Utility District
Population Served: 1,000
Service Area: Not Available
Sewer System: 16.3 mi. of combined sewer
The combined sewer system owned and operated by the Paris Utility District
has one overflow point. Utilization of an unused pretreatment facility for
storing excess wet weather flows has enabled the District to reduce the
frequency of CSO events. The District's wastewater system was designed
with pretreatment facilities for the two major industries in the city,a tannery
and a cannery. The tannery pretreatment facility is considered part of the
South Paris wastewater treatment plant.The tannery closed in 1985. In the mid 1990s, the tannery pretreatment facility was brought
back into service to store excess wet weather flows from the District's CSS and provide primary treatment during extreme events.The
tannery facility provides a total storage volume of 1.5 MG. Costs for returning the tannery facility to service were minimal because the
infrastructure was already in place; operation and maintenance costs are also quite small.The only true cost of the tannery storage is
its portion of the facilities debt service for plant modifications, which costs approximately $110,000 annually or $0.07/ga Hon.
Contact: John Barlow, Paris Utility District
TULSA, OK
Flow Equalization Basins
Responsible Agency: Tulsa Public Works
Tulsa's separate sanitary sewer system is divided into three major sewersheds,
85/000 with a wastewater treatment plant located in each. Multiple sanitary sewer
Service Area: Not Available evaluations have been performed to help Tulsa establish a plan for controlling
Sewer System: 1,800 mi. of sewer SSOs. SSO abatement efforts in the Northside Sewershed have facilitated on the
attenuation of storage of excess wet weather flows.Tulsa has constructed three
near-surface storage basins located remotely in the Northside Sewershed, and
one FEB located within the bounds of the wastewater treatment plant.The four basins together provide a total of 83.2 MG of storage,
with the treatment plant FEB accounting for 13 MG.The treatment plant site is large enough to accommodate the FEB as well as all
anticipated future additions to the plant.The Northside FEB is used when a large wet weather event overwhelms the capacity of the
three upstream storage basins.The construction cost for the Northside FEB was approximately $3.81 million or $0.35/gallon.
More information athttp://www.cityoftulsa.org/Public+ Works/wastewater/wastewater+treatment+process.htm
STR-22
-------
Storage Facilities: On-site Storage
References
Metcalf and Eddy, Inc. 2003. Waste-water Engineering:
Treatment, Disposal, and Reuse, 4th ed. Boston: Irwin
McGraw Hill.
Oklahoma Department of Environmental Quality
(OKDEQ). 2002. "Title 252: Oklahoma Administrative
Code Chapter 656 Water Pollution Control Facility
Construction." Retrieved January 27, 2003.
http://www.deq.state.ok.us/rules/656-correction.pdf
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
STR-23
-------
-------
RIPTION
Supplemental Treatment
Overview
When wet weather flow rates exceed available sewer system
or treatment capacity, constructing supplemental treatment
facilities may be a cost-effective alternative to expanding
existing conveyance capacity or treatment facilities.
Supplemental treatment facilities are designed solely
to treat excess wet weather flows; the level of treatment
provided is typically driven by regulatory requirements.
Supplemental treatment facilities can be located and
configured in multiple ways, including:
• Providing treatment at established overflow locations
by installing a small scale treatment process at or near
a known CSO or SSO location. For example, a vortex
separator with disinfection capabilities might be
installed near a CSO outfall. The treated effluent would
be discharged directly to a receiving water.
• Constructing a separate treatment facility upstream
of the existing treatment plant. Such a facility would
accept and treat excess wet weather flows that might
otherwise result in untreated CSOs or SSOs from one
or more locations in the sewer system; for example, a
ballasted flocculation treatment process constructed
in a capacity-constrained area of the sewer system.
Effluent would be discharged directly to a receiving
water from this facility.
• Adding parallel treatment process(es) at the existing
treatment plant that would operate as necessary during
wet weather. To be successful, this requires sufficient
sewer system capacity to deliver wet weather flows to
the existing treatment plant. Effluent from the parallel
treatment process would be discharged directly or
recombined with flows from existing treatment units
prior to discharge.
For any of these configurations, the selection of a specific
supplemental treatment technology will be driven by wet
weather flow characteristics. Important characteristics to
consider include:
• Frequency of wet weather events requiring
supplemental treatment;
• Limited event duration, often lasting less than 24
hours;
• High flow rate and volume with potential peak wet
weather flows of four to 20 times the average daily
flow; and
• Weak influent pollutant concentrations, diluted by
storm water inflow/infiltration (I/I).
These flow characteristics can pose technical challenges to
efficient and effective treatment. Supplemental treatment
facilities must be able to handle sudden increases in flow at
unplanned times, have quick start-up time, or in the case of
biological processes, quick acclimation time after extended
periods of no flow (or low flow conditions), and provide
adequate treatment despite significant variation in influent
pollutant concentrations.
The technologies best suited for treating excess wet
weather flows commonly involve physical or chemical
processes rather than biological processes. The applicability
of biological treatment processes is limited by factors
including:
• Biological processes do not respond well to adverse,
intense, and intermittent flow conditions typical of wet
weather events.
• Rapid changes in the amount and quality of the
influent reduce biological process treatment efficiency.
In some cases, large hydraulic loads can wash out the
microorganisms necessary for treatment.
• Microorganisms need a minimum level of food (i.e.,
organic matter) in the influent to survive. Therefore,
it is often technologically and operationally difficult,
if not impossible, to maintain a large enough
microorganism population during dry weather or low
flow periods, so that there is a sufficient population
available for biological treatment of large wet weather
flows.
-------
Report to Congress on the Impacts and Control ofCSOs and SSOs
Trickling filters are the biological treatment technology
option considered most operationally feasible for treating
excess wet weather flows. This is based on their ability to
handle peak flow conditions with less likelihood of upset,
relative to conventional activated sludge processes (WEF
1998). In a trickling filter system, microorganisms are
maintained as a biological film attached to a fixed media.
In contrast, microorganisms in an activated sludge process
are suspended in a less stable, liquid media. Nonetheless,
supplemental treatment facilities with any biological
process must operate continuously with a minimum flow
rate to maintain the biomass necessary for treatment of wet
weather flows. During dry weather, effluent from biological
supplemental treatment facilities is typically returned to the
sewer system for further treatment and discharged at the
wastewater treatment plant.
A number of physical and chemical treatment technologies
are suited for use as supplemental treatment facilities
handling excess wet weather flows. These include:
Primary clarification
Excess wet weather flows enter a large basin where the
velocity of flow decreases, allowing solids to settle to the
bottom of the tank and floatable materials (e.g., grease
and debris) to rise. Mechanical equipment skims the
floating material, while other mechanical devices collect
and remove settled material from the bottom of the
basin.
Screening
Excess wet weather flows are strained through a mesh
of metal, plastic, ceramic, or cloth. Solids are collected
on the surface of the screen where they are removed by
mechanical scraping, a spray mechanism that washes
solids off the screen, or by gravity. Various screen
aperture sizes are available; solids removal efficiency
decreases as the aperture increases.
Vortex separators
Vortex separators use centripetal force, inertia, and
gravity to remove floatables, trash, and other settleable
solids from excess wet weather flows. Additional
information on vortex separators is presented in
"Vortex Separators Technology Description" in
Appendix B of the Report to Congress on Impacts and
Control of Combined Sewer Overflows and Sanitary
Sewer Overflows.
Ballasted flocculation
In ballasted flocculation or sedimentation, a metal salt
coagulant is added to the excess wet weather flows to
aggregate suspended solids. Then, fine-grained sand,
or ballast, is added along with a polymer. The polymer
acts like glue which bonds the aggregated solids and
sand. The process increases the particles' size and mass
which allows them to settle faster. The high dosages of
fiocculent may require pH adjustments.
Chemical flocculation
Similar to ballasted flocculation, chemical flocculation
is a high-rate treatment process that adds metal salts
and polymers to clump particles together. Depending
on their density, the clumps will either sink to the
bottom or float to the surface where they can be
removed.
Deep bed filtration
A deep bed filter system consists of a series of large
tanks (depths greater than 6 feet) filled with coarse
medium (typically sand or anthracite). Excess wet
weather flows are directed to the top of each tank and
exit at the bottom of the tank. Pollutants can either
attach to the filter media or become trapped in the
interstitial space of the filter; the filter is later cleaned
through backwashing. Chemical additives can be used
to improve removal rates.
Key Considerations
Applicability
Supplemental treatment facilities are not intended to
treat dry weather flows from combined or sanitary
sewer systems, although biological facilities will need
to be operated continually. The type and location of
supplemental treatment facilities will be driven by site-
specific considerations, which include:
• State and federal permit requirements and effluent
limits;
• Characteristics of the excess wet weather flows;
• Land or space constraints;
• Capacity constraints within the existing sewer system
or treatment facility;
• Anticipated population growth; and
• Financial resources.
For example, if available land is a constraint, a facility with
a large "footprint" would not be appropriate. Alternatively,
if the existing sewer system cannot convey all of the wet
weather flow to the WWTP, a supplemental treatment
facility upstream of the plant may be the most practical
alternative.
It should be noted that primary clarification and trickling
filter technologies can have a difficult time handling
the highly variable flows associated with wet weather
TMT-2
-------
Treatment Technologies: Supplemental Treatment
events; these technologies may, therefore, require some
type of flow equalization to operate efficiently. Adequate
disinfection of treated excess wet weather flows is also a
concern. High flow rates can result in reduced exposure to
the disinfecting agent and reduced pathogen inactivation.
Increased solid concentrations may also exist in treated wet
weather flows, which can shield pathogens from exposure
to the disinfectant. Specific wet weather considerations
related to disinfection technologies are discussed in more
detail in the "Disinfection Technology Description" in
Appendix B of the Report to Congress on Impacts and
Control of Combined Sewer Overflows and Sanitary Sewer
Overflows. The advantages and disadvantages of each of
the aforementioned supplemental treatment processes are
summarized in Table 1.
Table 1. Advantages and disadvantages of various supplemental treatment technologies.
Technology
Primary Clarification
Advantages
1 Little manual operation
Disadvantages
• Large"footprint"
• Reduced retention and settling time (i.e., residence
time) and possible short circuiting during high flow
rates
• Lack of removal of dissolved or soluble pollutants
• Need for significant periodic maintenance
requirements
Screening
1 Small "footprint"
1 Little manual operation
1 High reliability with proper operations and
maintenance (O&M)
1 Low energy consumption
• Susceptible to clogging or poor solids removal
• Require regular operator observation,especially
microscreens
• Prompt solids disposal required due to potential odor
problems
• Incomplete removal of solids from wastewater
(coarse and fine screens generally only remove
floatables and visible solids)
• High cost for high performance microscreens
Vortex Separation
1 Small "footprint"
1 Ability to handle high hydraulic loading rate
1 No moving parts (no mechanical
maintenance)
1 Low construction cost
• Inability to remove fine solids and dissolved or
soluble pollutants
• Loss of floatables to overflow during extremely high
flows
• Potential loss of foam and floatables in initial
overflow
• Manual cleaning needs for settled solids
Ballasted Flocculation
• Small "footprint" (typically 5-15 percent of
the space required for conventional primary
clarification)
• Ability to handle high hydraulic loading
rate(s)
• Reduced capital cost relative to
conventional clarification
• Ability to treat rapidly varying flows
• Ability to consistently achieve secondary
treatment concentration standards for BOD
andTSS
• Limited ability to remove soluble pollutants
• Increased operational cost relative to biological
treatment or conventional clarification due to the
cost of the chemicals and sludge disposal along with
ballasted media
Chemical Flocculation
1 Production of concentrated sludge,
requiring no additional thickening
equipment
1 Ability to handle high hydraulic loading rate
1 Ability to treat rapidly varying flows
• Limited ability to remove soluble pollutants
• Potential increase in sludge produced due to the
addition of treatment chemicals
• Increased operational costs relative to biological
treatment or conventional clarification due to the
cost of the chemicals
Deep Bed Filtration
• Ability to treat high and rapidly varying
flows
• Ability to consistently achieve secondary
treatment concentration standards for BOD
andTSS
1 High initial construction costs
1 Limited ability to remove soluble pollutants
1 Frequent backwash requirements to avoid clogging
Trickling Filters • Small "footprint"
• Ability to achieve all secondary treatment
requirements
• Rapid reduction of soluble BOD in wet
weather flow
• Ability to treat high and rapidly varying
flows
1 Continuous operation required
1 Degraded removal efficiencies when excess biomass
exists
1 High clogging potential
1 Regular operator supervision and maintenance
requirements
1 Potential odor and snail population problems
TMT-3
-------
Report to Congress on the Impacts and Control ofCSOs and SSOs
Cost
Performance information for each of these technologies is
presented in Table 2. Screening data are presented according
to screen aperture size in millimeters. Typical performance
for hydraulic loading capacity, BOD removal, and TSS
removal is presented where available. The range in observed
performance is largely due to changes in either hydraulic
loading rates or influent characteristics (e.g., concentration,
fraction of soluble pollutants). Where typical ranges were
not available, data for performance at a single location are
provided with notation.
Capital cost information for each supplemental treatment
technology is summarized in Table 3. Cost per gallon of
capacity is provided where possible.
The capital costs for biological trickling filters are generally
greater than capital costs for physical and chemical
alternatives. In comparing daily operating costs, biological
processes are typically significantly less expensive to operate
Table 2. Performance data summary for supplemental treatment technologies.
Technology
Primary Clarification
Screening
Coarse (5-25 mm)
Fine (0.1 -5 mm)
Micro (less than 0. 1 mm)
Vortex Separation
Ballasted Flocculation
Chemical Flocculation
Deep Bed Filtration
Trickling Filters (with
settling)11
Source(s)
Metcalf and Eddy 1991;
NEIWPCC1 998; WEF 1996
Metcalf and Eddy 1991
EPA 1 996;
Boner eta/. 1995;
WERF 2002
Radick eta/. 2001;
Scruggs era/. 2001;
Vick 2000;
Poppeera/. 2001
Metcalf and Eddy 1991;
Moffa 1 997
El lard era/. 2002
Metcalf and Eddy 1991;
WEF 1998
Hydraulic Capacity
(gpd/ft2)
600-3,000
21,000-86,000
150-1,400
150-1,400
Up to and greater than
1 00,000
Up to 90,000
Up to 20,000
Not Available
Up to 11, 000
BOD Removal
(Percent)
25-40
Not Available
Not Available
Not Available
Up to 55 a
65-80
40-80
65b
40-90
TSS Removal
(Percent)
50-70
15-30
40-50
40-70
5-60
70-95
60-90
87 b
Not Available
" Based on two monitored events (Boner et. al. 1995); limited data exist since BOD is not a common performance indicator for vortex
separators.
b Average performance based on pilot test data from Jefferson County, Alabama (Ellard et al. 2002).
c High-rate trickling filters achieve 65-85 percent BOD removal. Related technologies, including rotating biological contactors and packed-
bed reactors, use the same processes as trickling filters and have similar removal rates, ad vantages, and disadvantages.
TMT-4
-------
Treatment Technologies: Supplemental Treatment
because of the chemical costs associated with physical or
chemical treatment. Supplemental biological treatment
processes need to be operated continuously, however, so the
actual annual operating costs for a biological supplemental
process will likely be greater than for a physical or chemical
supplemental process. For example, annual operation and
maintenance (O&M) costs for a 10 MGD trickling filter
facility are estimated at $150,000 (EPA 2000). Assuming it
operates 365 days per year, daily operating costs are $411
per day. In comparison, annual O&M costs for a 10 mgd
ballasted flocculation facility are estimated at $49,000
(Wendle 2002). Assuming this facility operates eight days
per year (a conservative estimate based on an expected two
to four events per year in Lower Paxton Township), daily
operating costs are $6,125 per day.
Table 3. Performance data summary for supplemental treatment technologies.
Technology
Primary Clarification
Screening
Vortex Separation
Vortex Separation with
Screening
Ballasted Flocculation
Chemical Flocculation -
Aluminum as Additive
Chemical Flocculation -
Ferrous Sulfate as Additive
Deep Bed Filtration
Trickling Filters
Source
Hufford 2001
EPA 1 999
Sacramento 1999
Sacramento 1999
Wendle 2002
Hufford 2001
WERF 2002
Bremerton 2002
Hewing et.al. 1995
Hewing et.al. 1995
Chandler 2001
EPA 2000
Capacity
(MGD)
78
0.75-375
1.8-16.2b
0.71-194
15
78
100
20
Not
Available
Not
Available
360
1-100
Estimated Total
Capital Cost a
$11.0 million
$40,800-$2.2 million
$10,000-$50,000
$13,000-$630,000
$5.5 million
$12.4 million
$20.0 million
$4.0 million11
$0.50 (cost per pound)
$0.17 (cost per pound)
$55 million6
$760,000-$63.4 million
Unit Cost a
(Per Gallon/Day
of Capacity)
$0.14
$0.01-$0.05
$0.01
$0.01-$0.02
$0.37
$0.16
$0.20
$0.20
$0.04 (per gallon
treated) d
$1.03 (per gallon
treated) d
$0.15
$0.63-$0.76
"Costs in 2002 dollars.
b Vortex separator capacities are hydraulic capacities. Manufacturer recommended design capacities for optimal TSS removal
are generally 25 percent of the hydraulic capacities.
c Includes costs for a 20 MGD Ultraviolet (UV) disinfection process.Cost for ballasted flocculation alone was not available.
d Capital costs for chemical feed mechanisms not available.Treatment costs include chemical costs and sludge handling costs.
Ferrous sulfate generates larger sludge volumes than aluminum, significantly increasing treatment costs.
e Includes costs for a 360 MGD UV disinfection process. Cost for deep bed filtration alone was not available.
TMT-5
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Implementation Examples
JEFFERSON
COUNTY, AL
Deep Bed Filter to Manage Peak Wet Weather Flows
Responsible Agency: Jefferson
County Environmental Services
Population Served: 232,000
Service Area: Not Available
Sewer System: 3,100 mi. of sewer
geology, and sewer system
age have contributed to extreme peak wet weather flow issues for the
county.
Under consent decree, Jefferson County will spend approximately $200
million for the construction of a deep bed filter supplemental treatment
facility. The deep bed filter facility will be constructed on a 450-acre site
and will discharge through a separate outfall. Construction is scheduled
for completion in late 2003. During pilot testing of the filter technology,
the best effluent and longest filter runs were achieved with no chemical
addition. Pilot testing performance showed average removals of 87
percent of TSS and 65 percent of BOD, on average.
To prevent filter clogging from high influent flow and solids loadings, new
methods of operating and backwashing were developed during the pilot
study.These methods are now patented or patent-pending.
Jefferson County's Village Creek Wastewater Treatment Plant receives an average daily
flow of 40 MGD; peak flows exceed 400 MGD once per year on average. Exceedence of
available 120 MGD of primary treatment and disinfection capacity at the treatment plant
occurs an average 41 times per year (based on data from 1997-2001). Flows exceeding
the 60 MGD of secondary capacity occur more frequently. Elevated wet weather flows
have continuously exceeded treatment capacity for as long as six days. A combination of
rainfall patterns,topography, Deep bed fj|ter construction costs.
Component
Influent tunnel (15 foot diameter)
Pump station (360 MGD)
Surge basins (20 basins, total capacity:
90 MG)
Deep bed filters plus UV disinfection
(360 MGD) (22 filters, each at 1,167 ft2)
24 megawatt generator building and
equipment (primarily for pump station
and UV operation)
Site work/access, road, and
miscellaneous
Total:
Contract Cost
(Million)
$17.0
$46.0
$54.2
$55.0
$22.0
$14.3
$208.4
Contact: Harry Chandler, Assistant Director of Environmental Services, Jefferson County
SYRACUSE, NY
Microscreens to Treat CSOs
Responsible Agency: Onondaga
County Public Utilities
Microscreen performance data (EPA 1979).
Aperture (microns)
Hydraulic loading rate
(gpd/ft2)
Average influent TSS
concentration (mg/L)
Average effluent TSS
concentration (mg/L)
Average TSS removal
(Percent)
2,500- 4,000-
11,000 18,000
619
290
58
308
172
45
16,000-
95,000
284
196
32
The Syracuse demonstration program evaluated the treatment of CSOs
with screening. Three screening units, ranging from an aperture size of
23 microns to 105 microns, were used in this program.The table on the
left lists the hydraulic loading rates and averageTSS removal efficiencies
associated with each of these microscreens.These results show that as
aperture increases, hydraulic loading rates also increase. As aperture
increases, however, the TSS removal efficiencies decrease.
Contact: Rich Field, EPA Office of Research and Development, Edison, NJ
TMT-6
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Treatment Technologies: Supplemental Treatment
TACOM A, WA
i
Ballasted Flocculation to Manage Wet Weather Flow
Se
"
Responsible Agency: City ofTacoma
Population Served: 258,000
Service Area: Not Available
Sewer System: 700 mi. of sewer
The City of Tacoma's Central Treatment Plant (CTP) receives flow from a separate sanitary
sewer system serving a population of 208,000. The CTP has a hydraulic capacity of 103
MGD (primary plus disinfection),and a peak biological treatment capacity of 78 MGD.The
sewer system can currently deliver up to 110 MGD to the CTP.
The CTP has reached the criterion specified in their permit that triggers a requirement
to develop a plan for maintaining adequate capacity. The city plans to install a 78
MGD ballasted flocculation process at the CTP parallel to the existing processes.The ballasted flocculation process alone will cost
approximately $12.4 million. All related peak wet weather flow facility upgrades are estimated at $50.7 million. In comparison, to
expand the existing activated sludge processes by 78 MGD would cost an estimated $130 million; this estimate does not include the
cost for additional primary clarification capacity.
During pilot testing, the ballasted flocculation process reached acceptable performance levels within 10-15 minutes of start-up. Pilot
testing performance data, collected over a nine-day period, indicate effluent TSS concentrations below 30 mg/L(with the exception
of the first day) and percent removals for TSS ranging from 79-92 percent. Effluent BOD concentrations ranged from approximately
20-42 mg/L, and removal rates for BOD ranged from 63-73 percent (Tacoma 2000).The lower percent removals generally occurred
during weaker influent conditions.
When the actual ballasted flocculation process is constructed and operated for wet weather treatment, effluent from the process
will be separately disinfected and blended with disinfected biologically treated effluent prior to discharge. The blended effluent
is expected to meet permitted effluent concentrations and removal efficiencies. The ballasted flocculation process is expected to
operate a maximum of 5.5 days in a row, 8 days in a month, and 21 days per year (Tacoma 2001).
Contact: David Hufford, Division Manager, Environmental Services/Wastewater Management, City ofTacoma
BREMERTON, WA
Ballasted Flocculation to Treat CSOs
Responsible Agency: City of Bremerton The Qty of Bremerton maintains a partially combined sewer system that
Population Served: 37,000 provides service to approximately 37,000 people.The WWTP receives an average
Service Area: 5.2 sq. mi. annual flow of 7.6 MGD and has a peak hydraulic capacity of 29.5 MGD. During
Sewer System: Not Available periods of wet weather, however, flows in excess of 38 MGD have been delivered
to the plant. Currently, Bremerton has 16 permitted CSO outfalls. As part of their
CSO long term control plan, the city constructed the Pine Road Eastside CSO
Treatment Facility.The CSO treatment facility was completed in December 2001.
The facility uses ballasted flocculation in combination with UVdisinfection.Total construction costs were $4 million.The CSO treatment
facility also includes a 100,000 gallon storage tank that was constructed in 2000 for an additional $400,000 (Bremerton 2002).
No performance data are currently available for the constructed facility (Bremerton 2002). Pilot testing performance showed a 71
percent removal ofTSS,63 percent removal of total BOD, and 46 percent removal of soluble BOD, on average. During pilot testing, the
ballasted flocculation unit reached peak efficiency within 10 minutes of start-up.
Contact: John Poppe, Wastewater Manager, City of Bremerton
TMT-7
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Report to Congress on the Impacts and Control ofCSOs and SSOs
References
Boner, M.C., et al 1995. "Modified Vortex Separator and
UV Disinfection for Combined Sewer Overflow Treatment."
Water Science and Technology. Vol. 31( No. 3-4).
Bremerton, City of 2002. "City of Bremerton Public
Works and Utilities' Wastewater/CSO Update." Retrieved
December 11,2002.
http://www.cityofbremerton.com/content/ww_
csoupdate.html.
Chandler, Harry, Assistant Director of Environmental
Services, Jefferson County. Interview by Limno-Tech, Inc.,
Birmingham, AL. Fall/Winter 2001.
Ellard, Gregory, Meek, R., and H. Chandler. 2002. Direct
Filtration for Wet Weather Conditions. Presented at
Water Environment Federation Technical Exhibition
and Conference (WEFTEC) Chicago, IL. September 29 -
October 2, 2002.
EPA. 1979. Disinfection/Treatment of Combined Sewer
Overflows - Syracuse, New York. Prepared by O" Brien and
Gere Engineers, Inc. EPA 600-2-79-134.
EPA. 1996. Assessment of Vortex Solids Separators for the
Control and Treatment of Wet-Weather Flow. EPA 832-B-96-
006.
EPA, Office of Water. 1999. Combined Sewer Overflow
Technology Fact Sheet: Screens. EPA 832-F-99-040.
EPA, Office of Water. 2000. Wastewater Technology Fact
Sheet: Trickling Filters. EPA 832-F-00-014.
Hewing, Albert, et al. 1995. "Reducing Plating Line Metal
Waste." Pollution Engineering.
Hufford, David, Division Manager, Environmental Services/
Wastewater Management, City of Tacoma. Interview by
Limno-Tech, Inc., October 2001. Tacoma, WA.
Metcalf and Eddy, Inc. 1991. Wastewater Engineering:
Treatment, Disposal, and Reuse. 3rd Ed. Boston: Irwin
McGraw Hill.
Moffa, P.E. (Ed.). 1997. Control and Treatment of Combined
Sewer Overflows. 2nd ed. New York: Van Nostrand Reinhold.
New England Interstate Water Pollution Control
Commission (NEIWPCC). 1998. Technical Report #16:
Guides for the Design of Wastewater Treatment Works.
Wilmington, MA: NEIWPCC.
Poppe, John, Wastewater Manager, City of Bremerton. 2002.
Interview by Limno-Tech, Inc., Fall 2002. Washington, DC.
Poppe, John, et al. 2001. "High-Rate Wet Weather Solution."
Public Works. Vol. 132 (No. 8).
Radick, Keith A. and Morgan, Marc A. Ocotber 2001.
Ballasted Flocculation: A Technology for Long Term CSO
Control. Presented at Water Environment Federation
WEFTEC Conference Atlanta, GA. October 13 - 17, 2001.
Sacramento, County of. 1999. Stormwater Management
Program: Investigation of Structural Control Measures for
New Development. Prepared by Larry Walker Associates, Inc.
Retrieved December 12, 2002
www.sacstormwater.org/const/manuals/pdf/scm99_
scm99.pdf
Scruggs, Caroline and C. Wallis-Lage. 2001. Ballasted
Flocculation: A Wet-Weather Treatment Solution? Presented
at Water Environment Federation WEFTEC Conference
Atlanta, GA. October 13 - 17, 2001.
Tacoma, City of. 2000. Ballasted Sedimentation Pilot
Study Report and Feasibility Analysis, Central Wastewater
Treatment Plant, City of Tacoma. Prepared by Parametrix,
Inc. Sumner, WA: Parametrix.
Tacoma, City of. 2001. Facilities Plan: Central Wastewater
Treatment Plant, City of Tacoma - Draft Final Edits.
Prepared by Parametrix, Inc. Sumner, WA: Parametrix.
Vick, Rebecca Chambers. 2000. "High-Rate Clarification
Takes the Prize." Pollution Engineering. Vol. 32 (No. 10).
Water Environment Federation (WEF). 1996. Operation of
Municipal Wastewater Treatment Plants, Manual of Practice
No. 11. 5th Ed, Vol. 2. Alexandria, VA: WEF.
Water Environment Federation (WEF). 1988. Design of
Municipal Wastewater Treatment Plants, Manual of Practice
No. 8. 4th Ed., Vol. 2. Alexandria, VA: WEF.
Water Environment Research Foundation (WERF). 2002.
Best Practices for the Treatment of Wet Weather Wastewater
Flows. Prepared by Brashear, Robert, et. al. WERF Project
No.OO-CTS-6. Alexandria, VA: Water Environment
Foundation; London, United Kingdom: IWA Publishing.
Wendle, Jeff, CTE Engineering Services. Interview about
Lower Paxton Township, PA by Limno-Tech, Inc., August
200 I.Ann Arbor, MI.
TMT-8
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Treatment Technologies: Supplemental Treatment
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
TMT-9
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-------
Plant
RIPTION
Overview
Excess wet weather flows can cause sudden hydraulic surges
and changes in pollutant loads that adversely affect the
performance of wastewater treatment plants (WWTP).
Excess wet weather flows can disrupt treatment processes
and result in the discharge of untreated or partially treated
sewage. As an alternative to constructing supplemental
treatment units to handle excess wet weather flows,
modifications of existing facilities may be sufficient to
achieve the needed capacity and treatment efficiencies.
In general, these modifications involve either process
control changes or physical reconfiguration of unit
processes. Process control changes are operational;
examples include the addition of chemicals to a clarifier
to enhance settling and the modification of return sludge
flow rates. Physical reconfiguration of unit processes
involves actual modification of the internal components
of a process. For example, a clarifier's internal components
would be redesigned to improve its hydraulics and expand
the range of flow and solids load it is able to handle.
In addition to unit process modifications, system-wide
or overall plant modifications can be used to improve
performance with respect to treatment of excess wet
weather flows; examples include flow distribution and real-
time control.
A generalized schematic of a WWTP depicting typical unit
processes and the associated sludge handling is shown in
Figure 1. This technology description first describes unit
process modifications and then overall plant modifications
which can improve the ability of a WWTP to provide
treatment for excess wet weather flows.
Unit Process Modifications
Clarification Processes
The performance of both primary and secondary
clarifiers impacts the performance of biological
secondary treatment units. The modifications described
below pertain to both primary and secondary clarifiers,
unless otherwise noted.
Influent
Effluent
Figure 1. Schematic of a typical WWTP.
Chemical enhancement can improve solids removal
in primary and secondary clarifiers. Two classes
of chemicals used are coagulants and flocculants.
Coagulants neutralize the charge associated with
suspended solids in wastewater. This is important
since most suspended solids in water are negatively
charged and particles with the same charge repel
each other. With the charges neutralized, the particles
are able to stick together and form larger, heavier
particles which settle faster. Flocculants (also referred
to as coagulant aids) can help bridge and bind solids
together, further increasing particle size, density, and
settleability. Treatment plant operators may choose to
use one or both types of chemicals depending on the
wastewater characteristics, chemical costs, and other
factors. Common coagulants include: aluminum sulfate
(alum), polyaluminum chloride, ferric chloride, ferric
sulfate, ferrous sulfate, calcium hydroxide carbonate
(slaked lime), calcium oxide (quicklime), and sodium
aluminate. The degree of clarification obtained when
chemicals are added to untreated wastewater depends
on the quantity of chemicals used, characteristics of
the wastewater, and the care with which the process is
-------
Report to Congress on the Impacts and Control ofCSOs and SSOs
monitored and controlled. For any chemical application
to be effective, the chemicals must adequately mix with
the wastewater.
Baffles are most commonly used to interrupt or
disperse density currents. Density currents travel at a
higher velocity than surrounding waters and can carry
solids through a clarifier and over its effluent weir,
reducing effluent quality. The occurence of density
currents is also referred to as short-circuiting. These
currents may exist in both circular and rectangular
clarifiers, and may become more apparent and
problematic during peak flows (NYSDEC 2001). Dye
testing can be used to identify the existence of density
currents and assist in determining the best baffle
configuration. Baffles can be of any size and configured
in multiple ways (e.g., placed in the top, middle, or
bottom of the tank; constructed of one solid board or
several boards with gaps in between). Various materials
can be used to construct the baffle, including wood,
fiberglass, plastic, and metal. In a rectangular clarifier,
a baffle is a thin, vertical wall of material placed across
the width of a clarifier. It may span up to the entire
width and a portion of the depth of the clarifier. In
a circular clarifier, baffles are commonly angled at
45-60 degrees along the perimeter of the clarifier wall,
but they can also be placed perpendicular to the wall.
Cross-section views of both placements in a circular
clarifier are shown in Figure 2.
Water surface
lOutlet weir
Water surface
lOutlet weir
Baffle
'wastewater flow
45-60 degree angle
90 degree angle
Figure 2. Example baffle replacement in circular clarifiers.
Lengthening weirs can reduce the loss of solids during
periods of excess wet weather flow. For rectangular
clarifiers, weirs can be lengthened by placing additional
lateral weir troughs. In circular clarifiers with one
peripheral effluent weir, weir lengths are normally
sufficient under average as well as peak flow conditions.
For circular clarifiers with double-sided effluent weir
troughs, eliminating identical V-notch spacing on outer
and inner weirs can reduce solids loss during periods of
excess wet weather flow. This can be accomplished by
blocking alternating V-notches on the outer weir with
plywood or other materials.
Biological Suspended Growth (Activated Sludge)
Processes
Maintaining a concentration of biological solids in
the activated sludge system higher than necessary for
proper treatment will increase the potential for solids
loss during peak flow periods. Operators should try
to maintain the solids concentration that is necessary
to ensure adequate treatment. The concentration of
solids is managed primarily by controlling the total
sludge mass in the system. Although long-term changes
in total sludge mass must be made by adjusting the
sludge wasting rate, short-term changes can be brought
about by adjusting the return rate. Shifting the mode
of operation to step feed or contact stabilization can be
particularly effective, as described below.
Return sludge flow rate control is used to manage
the sludge mass and detention time in the aeration
basin of the activated sludge process. The return
sludge flow is settled biomass that is removed from
secondary clarifiers and recycled or returned back
into the aeration basin (see Figure 1). It is necessary
to return a portion of the secondary clarifier sludge
to the aeration basin because the sludge contains the
bacteria needed to maintain the biological treatment
process. It is important to note that the rate at which
the sludge is returned must be managed in accordance
with influent conditions, sludge settling characteristics,
and the dynamics of the biomass inventory which is
continuously shifting between the clarifiers and the
aeration basin. Understanding when to increase or
decrease the return sludge flow can assist in maximizing
secondary treatment capacity during periods of excess
wet weather flow and improve effluent quality.
The step feed mode of operation introduces settled
wastewater at several points in the aeration tank, as
shown in Figure 3. Step feed mode can be used to
handle increased organic loads by distributing them
evenly across the aeration basin, but primarily provides
more capability for handling hydraulic surges. To be
effective, this approach generally requires three or more
parallel channels in the aeration basin.
Contact stabilization is an operational modification
in which the feed point is moved downstream in the
TMT-12
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Treatment Technologies: Plant Modifications
Compressed air
pfflupnt I V ^ I T T I TT
Reactor
Primary effluent
Return sludge
Figure 3. Step feed mode of operation.
aeration tank approximately one-half to two-thirds
the length of the tank or into a separate tank. This
configuration is shown in Figure 4. Return activated
sludge is added to the basin inlet upstream of the feed
point and aerated before being blended with influent.
Similar to step feed, contact stabilization can reduce
solids loss during hydraulic surge events. Solids in the
reaeration basin are protected from the direct influent
flow, thereby minimizing the potential for solids
loss. Contact stabilization provides a relatively short
detention time, which increases system stability.
Biological Fixed Film Processes
The biomass of fixed film processes, such as trickling
filters and rotating biological contactors (RBCs), is
not as easily washed out as the biomass of suspended
growth processes. Nonetheless, their performance is
impacted by excess wet weather flows. Techniques for
improving the performance of fixed film processes
under wet weather flow conditions are described below.
For trickling filters, recirculation of flow is commonly
practiced to provide adequate wetting of the biological
media. For RBCs, recirculation of sludge may be
practiced to encourage some suspended growth and
maintain dissolved oxygen and hydraulic loading.
During peak flow periods, however, recirculation is
generally not necessary and can be temporarily reduced
or halted to allow increased capacity for peak flows.
Trickling filter flow distributors are used to spread
wastewater influent evenly over the biological media.
Distributor arms that are hydraulically driven may turn
at excessive speeds during peak flow periods, but can be
slowed by installing nozzles on the arms that discharge
in the opposite direction. The new nozzles can be
capped to return the arm to normal speed during
normal flow conditions. In practice, such changes are
not made routinely.
Trickling filters are sometimes operated in series or
sequentially. Pipes and pumping may be configured
between units, however, such that during peak flow
periods, the units could be converted to parallel
operation allowing flows to pass through all filters
simultaneously. This would increase the biological
treatment capacity by reducing the hydraulic loading
rate. Biochemical oxygen demand (BOD) removal
efficiency may be reduced by placing the units in
parallel operation; however, the reduced efficiency
Waste_sludge
Figure 4. Contact stabilizer mode of operation.
would be offset somewhat by the fact that each unit will
operate at or below design loading rates.
Chemical Disinfection Processes
During periods of excess wet weather flow, influent
exposure time to chemical disinfectants may be
insufficient for adequate disinfection. Key operational
variables for optimizing performance of disinfection
facilities include mixing and dosage. Poor disinfectant
mixing or poor diffuser placement can significantly
reduce effectiveness. For chlorine disinfection,
it is possible to provide adequate disinfection at
detention times of less than 15 minutes with the
appropriate dosage (NYSDEC 2001). Determining
the optimal dosage at high flows, however, requires
some experimentation. Additional information on
disinfecting wet weather flow is provided in the
"Disinfection Technology Description" in Appendix
TMT-13
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Report to Congress on the Impacts and Control ofCSOs and SSOs
B of Report to Congress on the Impacts and Control
of Combined Sewer Overflows and Sanitary Sewer
Overflows.
Overall Plant Modifications
Flow Distribution and Control
Treatment facilities that have multiple treatment
units used in a process must be able to control
the distribution of flow. In general, uneven flow
distribution can affect the hydraulic capacity in one
or more of the treatment units, which can have a
negative impact on performance (e.g., solids loss from
a secondary clarifier) (NYSDEC 2001). Flow control
can be incorporated into an existing facility through
the addition of adjustable control weirs or appropriate
valves.
Equal distribution of solids to the treatment processes,
such as return sludge, is also important. Unless
provided for in the design, equal distribution of solids
to the treatment units may not occur coincidentally
with the equal distribution of flow.
Sidestream Control
A sidestream is a liquid or sludge flow that is produced
by a treatment process; wastewater treatment plants
typically produce several sidestreams. Sidestreams are
either handled separately from the wastewater flow,
or returned to a specific unit process for additional
treatment or to support operation. Controlling
the timing and location of sidestream returns can
prevent overload of the treatment facility. Specifically,
consideration should be given to reducing or halting
sidestream returns during peak wet weather flows
(NYSDEC 2001).
Real-Time Automated and Remote Controls
Automated and remote operation controls, based on
real-time system information, can improve preparation
for and response to wet weather events. Real-time
information from the sewer system can allow operators
to anticipate the need for operational changes before
excess wet weather flows reach the treatment facility,
thereby optimizing the efficiency and effectiveness
of mode shifts or operational changes. Additional
information on the use of real-time control is provided
in the "Monitoring and Real-Time Control Technology
Description" in Appendix B of Report to Congress on the
Impacts and Control of Combined Sewer Overflows and
Sanitary Sewer Overflows.
At the treatment plant, automated or remote control
systems optimize adjustments to gates, valves, and
weir levels during wet weather events. Such real-time
controls have been shown to improve wet weather
operations by reducing CSO events and maximizing
sewer system storage capacity (Batzell 1994; Field
et al. 2000). Real-time control within individual
processes can also optimize unit process operation. For
example, real-time information on dissolved oxygen
concentrations in the aeration basin can optimize the
performance of an activated sludge process.
Key Considerations
Applicability
A performance evaluation should be done prior to any
plant modifications to determine whether it is feasible to
obtain the needed capacity from the existing unit processes.
Plant modifications are preferred over new construction
since the cost of plant modifications is relatively small
compared to new construction. Some of the recommended
modifications for improving peak wet weather flow
capacity, however, may result in increased effluent
concentrations of BOD or other constituents. The ability to
increase the capacity of existing processes must be balanced
with the need to meet short- and long-term permit limits.
In addition, modifications that require operator attention
before and after a wet weather event may interrupt regular
dry weather operations and potentially compromise the
quality of treated effluent during dry weather.
Cost
In general, the costs for the modifications described
above are low. Some modifications require only simple
changes in operation and no additional treatment process
units. Construction materials (e.g., lumber) for unit
reconfiguration are typically simple and readily obtainable.
Material costs for density current baffles built in-house,
for example, are quite low. In an article by the New York
State Department of Environmental Conservation, the
highest cost for a density current baffle reported was $300
(NYSDEC 2002). Further, the addition of baffles can often
be implemented by plant staff. Baffles commonly result
in TSS reductions of 25-35 percent under average flow
conditions and 40-50 percent under peak flow conditions
(NEFC02002).
Of the potential modifications presented, chemical
enhancement and real-time controls are expected to be the
most expensive. Chemical enhancement represents an on-
going cost that will vary depending on the chemicals used,
and the frequency and volume of usage. Sludge volume
and handling costs may also increase as a result of chemical
addition. Nonetheless, chemical enhancement in primary
TMT-14
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Treatment Technologies: Plant Modifications
clarifiers has been demonstrated to improve TSS removal
from the normal range of 50-70 percent to 80-90 percent.
Real-time control costs are summarized and presented in the
Monitoring and Real-Time Control Technology Description in
Appendix B of the Report to Congress on Impacts and Control
of Combined Sewer Overflows and Sanitary Sewer Overflows.
Case studies for larger sewer systems indicated capital
costs in millions of dollars. These systems represent highly
sophisticated automated and predictive technology. Simpler
Implementation Examples
WASHINGTON
COUNTY, NY
Use of Contact Stabilization and Baffles
Responsible Agency: Washington
County Sewer District #2
Population Served: 15,000
Service Area: 5.8 sq. mi.
Sewer System: 90 percent of combined
sewer; 10 percent of sanitary sewer
In March 1996, the NYSDEC and Washington County jointly conducted studies
to investigate methods for increasing the wet weather treatment capacity of the
existing secondary treatment process at the Sewer District #2 WWTP. The WWTP is
an activated sludge facility designed to treat an average dry weather flow of 2.28
MGD.The actual dry weather flow averages 2.1 MGD. However, during wet weather,
flow to the WWTP can exceed 15 MGD. Operators only allow 7.5 MGD to enter the
plant in order to protect unit processes. Prior to the study, flow to the activated
sludge process was further restricted to 5 MGD. During periods of wet weather, flows
entering the plant in excess of 5 MGD were bypassed around the activated sludge units and received only primary treatment and
disinfection.
Two techniques for increasing secondary treatment capacity were investigated: operating the activated sludge process in contact
stabilization mode; and evaluating primary and secondary clarifiers for short-circuiting.The studies found that the contact stabilization
mode could treat a higher flow rate than conventional operation. Conventional operations failed to meet permit limits at flow rates
greater than 7 MGD.The contact stabilization mode, however, was able to treat 7.5 MGD and meet permit limits.
Both the rectangular primary and circular secondary clarifiers exhibited short-circuiting. Baffle systems were designed for each, but
installation was delayed for the secondary clarifier. The system initially installed in the primary clarifier was a seven-foot high, solid,
mid-tank baffle that consisted of a used belt press supported by a wooden frame. The construction cost was less than $50. After
installation,testing showed no improvement in clarifier performance.The baffle was modified by cutting a six-inch opening every six
inches.This configuration reduced the density currents and reduced effluent suspended solids by 10 percent (NYSDEC 2001).This also
reduced the solids loading to the activated sludge process, improving overall treatment efficiency.
Contact: Joe McDowell, Washington County Sewer District
TMT-15
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Report to Congress on the Impacts and Control ofCSOs and SSOs
GRANVILLE, NY
Plant Modifications Increase Capacity
Responsible Agency: Village of Granville The VjNage of Granvi||e WWTP investigated methods for improving biological
Population Served: 2,646 trickling filter and secondary clarifier performance during periods of wet weather.
Service Area: 1 sq. mi. The WWTP experiences dramatic and prolonged peak flow events. Flows can rise
Sewer System: Not Available quickly from a dry weather flow of 0.3 MGD to more than 3 MGD,and the elevated
flows may last for up to a week. During periods of wet weather, the trickling filter
distributor arm speed would increase and result in sloughing of biomass from the
filter media. Effluent quality was often degraded for a period of time beyond the wet weather event,as much of the biomass necessary
for treatment was washed out.
During periods of high flow, the arm speed would increase from two revolutions per minute to more than seven revolutions per
minute.Two retro nozzles (pointing in the opposite direction of existing nozzles) were installed on each trickling filter arm.The retro
nozzles successfully slowed the arm speed to less than three revolutions per minute during periods of excess wet weather flow
(greater than 2 MGD) (NYSDEC 2001). Excess sloughing and loss of biomass was reduced, resulting in higher effluent quality.
Suspended solids removal was problematic in the rectangular secondary clarifiers during both dry and wet weather periods. Extensive
dye testing was conducted, and baffles were designed and installed.The initial baffle was installed at the one-third point in the tank.
The baffle was solid at the top with staggered 2x8 lumber at the bottom. Dye test results after installation showed a 6 percent
reduction in effluent solids. An additional baffle was designed and installed at the two-thirds point of the clarifier.This baffle was solid
from top to bottom, but left a 14-inch opening at the bottom of the tank and a smaller area for flow at the top. With the second baffle,
effluent solids concentrations were reduced by 19 percent (NYSDEC 2001).
Contact: Dan Williams, Village of Granville
Contact Stabilization Used for Treatment
Responsible Agency: Clatskanie People's Utility
District
Population Served: 4,300
Service Area: 3.5 sq. mi.
Sewer System: Not Available
The Clatskanie WWTP is an activated sludge treatment facility that
underwent a two-year full-scale performance evaluation of its wet
weather treatment capabilities. High inflow and infiltration in its
separate sanitary sewers resulted in the delivery of excess wet weather
flows. During the evaluation, the plant was operated in the conventional
mode during dry weather conditions.The average dry weather flow
was 0.2 MGD and the peak dry weather flow was 0.5 MGD. During wet
weather flows, the activated sludge process was operated in contact stabilization mode. By switching operational modes during
wet weather conditions, six to 12 times the average dry weather flow rate (approximately 1.25-2.3 MGD) was treated. For flows of
up to 1.25 MGD, the mean suspended solids and BOD5 effluent concentrations ranged from 2-24 mg/Land 6-11 mg/L, respectively.
Removal efficiencies for wet weather flows ranging from 0.5-2.3 MGD were 71 percent and 73 percent for suspended solids and
BOD5, respectively (Benedict and Roelfs 1981).
TMT-16
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Treatment Technologies: Plant Modifications
References
Batzell, Russell W. 1994. "Computer Control of CSOs," Civil
Engineering.Vol 64 (No.ll): 58-59.
Benedict, A.H. and Roelfs, V.L. 1981. Joint Dry/Wet Weather
Treatment of Municipal Waste-water at Clatskanie, Oregon.
EPA-600/2-81-061, NTIS PB 81-187262.
Field, R., Villeneuve, E., and Stinson, M. K. 2000. "Get
Real!" Water Environment & Technology. Vol 12 (No. 4): 64-
68.
NEFCO, Inc. 2002. "Baffle Basics...A Brief Tutorial."
Retrieved December 30, 2002.
http://www.nefcoinc.com/torial.html.
New York State Department of Environmental
Conservation (NYSDEC). 2001. "Wet Weather Operating
Practices for POTWs with Combined Sewers." Retrieved
June 26, 2003.
http://www.dec.state.ny.us/website/dow/bwcp/ww_
training.pdf
NYSDEC. 2002. "Clarifier Baffles Work." Retrieved
December 30, 2002.
http://www.dec.state.ny.us/website/dow/bwcp/tt_baffles.pdf
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
TMT-17
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RIPTION
Treatment T
les
Disinfection
Overview
Disinfection of wastewater is necessary for the protection of
public health. Therefore, municipal wastewater treatment
processes are typically followed by a disinfection process
that is designed specifically to inactivate bacteria, viruses,
and other pathogens in the treated wastewater. The
application of disinfection to CSOs and SSOs has been
more limited, however, owing to uncertainties in process
design, performance, and regulatory requirements. This
technology description describes two processes that have
been used to treat wet weather CSOs and SSOs: chlorine
disinfection and ultraviolet (UV) light. Other technologies
that have had more limited application in disinfecting
CSOs and SSOs include ozonation, chlorine dioxide,
peracetic acid, and electron beam irradiation. These will
not be discussed in this fact sheet; more information is
available in EPA's "Alternative Disinfection Methods" fact
sheet (EPA 832-F-99-033).
Chlorine Disinfection
Chlorine disinfection involves the application of
chlorine to wastewater to inactivate microorganisms.
Wastewater disinfection most often employs gaseous
chlorine. The gas is usually supplied in either 150-
pound or 1-ton cylinders. When added to wastewater,
gaseous chlorine undergoes hydrolysis and forms
a mixture of hypochlorous acid (HOC1) and
hydrochloric acid (HC1); some of the HOC1 further
dissociates to hypochlorite ion (OC1~). Hypochlorous
acid and hypochlorite ion provide the majority of the
disinfection. When ammonia is present, chloramines
are also formed, although they are less potent as
disinfectants.
Chlorine can also be applied in hypochlorite form.
The chemistry of hypochlorination is very similar
to gaseous chlorine in that the main agents of
disinfection are hypochlorous acid and, to a lesser
extent, hypochlorite ion. The two most commonly used
hypochlorites are sodium hypochlorite, a clear, yellow
liquid, and calcium hypochlorite, a dry solid that comes
in powder, granular, or tablet form.
Sodium hypochlorite, also known as bleach, is available
in strengths ranging from 1-16 percent, but typically
contains 12.5 percent available chlorine. Solutions
of less than one percent strength can be generated
electrochemically from salt brine solution, but must
be done on-site. Calcium hypochlorite is a solid
that contains 65-70 percent available chlorine. It is
commonly used in tablet erosion systems, which pass a
stream of water over the tablets and generate a solution
of generally less than one percent available chlorine.
The performance of a chlorine disinfection system can
be characterized in terms of the product of the chlorine
concentration in milligrams per liter (mg/L) and the
contact time in minutes, usually referred to as "CT."
Disinfection efficiencies are usually fairly consistent for
a given CT, and increase in proportion to increasing
CT. Decreased contact time can therefore be offset by
increased disinfectant concentration and vice versa.
Ultraviolet Light
Ultraviolet (UV) light disinfection involves the direct
exposure of the wastewater stream to UV light, which
alters genetic material in microbial cells and prevents
them from reproducing. Germicidal wavelengths range
from 200-320 nanometers (nm), with peak effectiveness
at approximately 260 nm. In UV disinfection systems,
a relatively thin film of wastewater flows past the UV
lamps, and for a few seconds, the microorganisms are
exposed to a dosage of UV energy.
Ultraviolet radiation is generated by striking an electric
arc through mercury vapor contained in a lamp.
Because ordinary glass absorbs UV light, the lamp is
made of special UV light transmitting quartz, polymer,
or silica. Factors that influence the level of radiation
emitted from UV lamps include mercury vapor
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Report to Congress on the Impacts and Control ofCSOs and SSOs
pressure, chemical composition of the quartz sleeve,
and electrical power input (Acher et al 1997).
Low-pressure, low-intensity lamps have found the
greatest application in disinfection of wastewater
treatment plant effluents, primarily because they emit
around 85 percent of their UV output at 254 nm, which
is close to the most effective germicidal wavelength of
around 260 nm. Due to their low-intensity, however,
the number of lamps required is relatively large, which
makes them impractical for high-rate applications such
as disinfecting CSOs and SSOs. There is effectively
no economy of scale in UV disinfection; much of the
capital and operating costs are directly proportional
to the number of bulbs, and the number of bulbs is
directly proportional to the flow being disinfected.
Medium-pressure, high-intensity lamps are becoming
more widely available and have been shown to be more
effective on lower-quality wastewaters such as CSO and
SSO discharges. In addition, higher intensity means that
fewer bulbs are required, which makes these systems
more economical for CSO and SSO applications.
Ultraviolet disinfection technologies fall into two
categories: closed systems and open channel systems.
Closed system contact units consist of UV lamps
encased in quartz around which wastewater flows.
Open channel systems consist of submerged UV lamps
either vertically or horizontally suspended in an open
channel. Both systems are typically modular in design
and are applicable to a wide range of flows.
To achieve inactivation, UV radiation must be absorbed
into the microorganism. Therefore, anything that
prevents UV light from reaching the microorganism
will decrease the disinfection efficiency. Other factors
that have been determined to affect disinfection
efficiency include (EPA 1999):
• Chemical and biological films that develop on the
surface of UV lamps
• Dissolved organics and inorganics in the
wastewater, especially iron
• Clumping or aggregation of microorganisms
• Turbidity
Color
• Incomplete exposure of wastewater to UV light
The effectiveness of UV disinfection is typically
characterized by the UV dose. The dose is most often
expressed in milliwatt-seconds per square centimeter
(mW-s/cm2), and is defined as the product of the
average intensity of UV energy emitted by the lamps (in
mW/cm2) and the exposure time (in seconds). UV dose
is analogous to the CT concept used to characterize
chlorine disinfection and is of similar use in comparing
results from studies.
Key Considerations
Applicability
Chlorine Disinfection
Chlorine is a fairly stable disinfectant that provides
continuous disinfection. Chlorine disinfection often has
significant space requirements; large tanks are usually
required to allow for sufficient contact time between
the chlorine and the wastewater. Chemical storage and
the location of feed equipment must also be considered.
Chlorine reacts quickly with many constituents of
wastewater including, but not limited to, pathogens,
such that not all of the chlorine added is available
for disinfection. The difference between the amount
added and the residual concentration (that is, the
concentration that persists long enough to provide
disinfection) is called the "chlorine demand" (White
1999). The initial chlorine demand of the wastewater
must be known to some extent so that enough chlorine
can be added to satisfy initial demand and still provide
a sufficient residual concentration.
Chlorine disinfection leaves residual chlorine in the
treated wastewater, which is highly toxic to aquatic
organisms. In addition, it may react with organics and
inorganics in wastewater to form toxic compounds
that can have long-term adverse effects on the receiving
waters. For these reasons, residual chlorine levels are
sometimes restricted by a facility's discharge permit,
and must be reduced by dechlorination. Dechlorination
is typically done with either sulfur dioxide (a gas) or
sodium bisulfite (a liquid).
Another effect of the chlorine disinfection process is
the formation of disinfection by-products (DBFs),
specifically halogenated organics such as total
trihalomethanes (THMs) and haloacetic acids. DBFs
form when natural organic matter reacts with free
chlorine added for disinfection or free bromine
that results from the chlorine disinfectant oxidizing
bromide ions in the wastewater. DBF formation is
affected by the type and concentration of natural
organic matter, chlorine form and dose, time, bromide
ion concentration, pH, organic nitrogen concentration,
and temperature. The utility of chlorine for disinfection
maybe limited where DBFs are subject to regulatory
limits. Removal of DBF precursors, modification of the
TMT-20
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Treatment Technologies: Disinfection
chlorine disinfection strategy, or changing disinfectants
are typically used to lessen DBF formation.
UV Disinfection
UV disinfection requires no chemical storage and
is very stable in this sense. Space requirements are
relatively small due to short wastewater contact times
and the lack of chemical storage.
Power consumption is an important consideration
in UV applications. The process is energy-intensive
compared to chemical methods. High-flow situations
present high power demands, and will usually require
an on-site generator, adding to the total construction
and operating cost.
Advantages
Chlorine Disinfection
The primary advantage of gaseous chlorine is its
low cost in relation to its overall effectiveness as a
disinfectant. The technology is well-developed and
straightforward to apply, and the chemical itself is
widely available.
Hypochlorination acts in a similar fashion as gaseous
chlorine and shares most of its advantages and
disadvantages. It provides reliable inactivation of
bacteria, it is widely available, and the technology is
fully developed. Liquid sodium hypochlorite is usually
somewhat more expensive than gas per pound of
available chlorine.
UV Disinfection
UV disinfection is attractive for disinfection of CSOs
and SSOs for several reasons. The disinfection process
requires much shorter detention times than chemical
methods, on the order of seconds as compared to
10 minutes or greater for chlorine. There are also no
chemicals to transport, handle, or store, which appeases
numerous concerns, including worker and public safety,
environmental impacts, and degradation of chemical
strength during storage. UV also does not form any
known, potentially toxic byproducts, nor does it leave
any toxic residuals.
Disadvantages
Chlorine Disinfection
Disadvantages of gaseous chlorine include poor
inactivation of viruses and protozoan cysts and
oocysts relative to bacteria, the formation of DBFs,
and reactions with ammonia that result in combined
chlorine residuals that are less effective disinfectants.
These issues are especially important when treating
CSOs and SSOs, since in many cases suspended solids
and ammonia levels are elevated in these flows. In
addition, the hazards posed by leaking chlorine gas may
make it infeasible for use at satellite locations, which
could be in heavily populated areas. Fire and building
codes may require scrubbers or other equipment to
mitigate leaks.
Hypochlorination shares some disadvantages with
gaseous chlorine, including lesser inactivation of
viruses and protozoa, the formation of DBFs, and
reactions with ammonia that lessen its effectiveness at
a given residual concentration. Although liquid sodium
hypochlorite is highly corrosive and must be handled
with care, it is generally considered to pose less of a
safety hazard than gaseous chlorine.
Solutions of sodium hypochlorite will decay in strength
over time, especially at higher concentrations and
temperatures. This can be a significant disadvantage for
CSO and SSO facilities that are operated infrequently
and which would require chemicals to be stored for
potentially long periods of time. Decay rates can be
attenuated by diluting the hypochlorite after delivery
to 10 percent or even 5 percent, although this requires
additional storage facilities. Calcium hypochlorite,
used in tablet erosion systems, has a much longer shelf
life than liquid sodium hypochlorite. Tablet erosion
systems, however, may not be able to provide large
enough volumes of chlorine solution with the short
notice given by CSOs and SSOs during many wet
weather events.
UV Disinfection
A major disadvantage of UV light disinfection of CSOs
and SSOs has been its sensitivity to wastewater quality.
Its efficiency is reduced by increased suspended solids
and turbidity. The buildup of mineral deposits on the
lamp sleeves also reduces effectiveness by reducing
the applied dose of UV light. Recent advances are
addressing these issues, however, by using higher
intensity lamps and more effective self-cleaning
mechanisms.
Cost
Chlorine Disinfection
Table 1 summarizes fecal coliform data for two
chlorine disinfection facilities (more information on
these facilities is provided in the case studies below):
Washington, D.C., and Acacia Park in Oakland County,
MI. The Washington, D.C., Northeast Boundary Swirl
Facility (NEBSF) also tests for enterococci, and these
results are also shown in Table 1. Samples at NEBSF are
taken both in the disinfection chamber and at the river
outfall.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
The table shows the variability of performance that is
often the case when treating CSOs and SSOs. A major
operational issue is optimizing the addition of chlorine;
the experience at these facilities and others has been
that inadequate pathogen reduction is usually the result
of insufficient chlorine levels. Achieving the desired
chlorine level requires reliable flow measurement and
knowledge of the strength of the chlorine solution.
Capital costs for construction of chlorine disinfection
facilities are usually proportional to the peak design
flow. The majority of the cost is in the construction of a
basin that provides sufficient contact time (for example,
15 minutes); a smaller portion consists of equipment,
such as feed pumps, mixers, and storage tanks. Analysis
of construction costs of CSO detention and treatment
facilities in the River Rouge area in southeast Michigan
showed that the equipment portion of the chlorine
disinfection costs were approximately three to four
percent of the total project cost (Tetra Tech MPS
2002). These facilities generally included significant
storage volume beyond what would be needed solely
for chlorine disinfection, however. If the basin costs
are adjusted to provide a 15-minute detention time,
the costs for the facilities average around $14,000 per
MGD of peak flow. Reducing the detention time to 10
minutes, which is feasible if highly efficient chemical
mixing is provided, reduces this cost to about $9,500
per MGD. Actual construction costs vary considerably
because of site-specific conditions.
Ultraviolet Light
UV systems do not have as long a record as chlorine
disinfection facilities in disinfecting CSOs and SSOs.
Pilot studies have shown, however, that fecal coliform
levels of 1,000 #/100 mL can be met consistently by
medium-pressure, high-intensity units operating
within their normal range of power usage (CDM 1997;
Curtis and Blue 1999). In another study, E. coli levels
of 126 #/100 mL were met by both low- and medium-
pressure systems treating effluent from a physical/
chemical process using alum as the coagulant (Matson
et al. 2002). The desired E. coli level was not met when
ferric chloride was used, however.
Capital costs for construction of UV disinfection
facilities are not well known, due to a lack of data
for this relatively new technology. As part of a CSO
disinfection pilot study, capital costs for construction of
UV disinfection facilities were projected by the US EPA
Office of Research and Development. In this study, it is
estimated that a UV disinfection facility that results in a
four-log reduction in fecal coliform with a peak flow of
88 MGD will cost approximately $27,600 per MGD of
peak flow (EPA 2002).
Table 1. Pathogen removal performance for chlorine disinfection facilities.
Geometric Mean Fecal Coliform (#7100 mL)
Geometric Mean Enterococci
(#/100mL)
1997
1998
1999
Jan-Mar 2001
Apr-Jun 2001
Jul-Aug2001
Number of
Samples
13
NEBSF
Acacia Park
Disinfection
Chamber
Disinfection
Chamber
TMT-22
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Treatment Technologies: Disinfection
Implementation Examples
WASHINGTON, DC
Northeast Boundary Swirl Facility (NEBSF)
Responsible Agency: District of Columbia Water
and Sewer Authority
Population Served: 572,000
Service Area: 19.50 sq. mi.
Sewer System: 1,800 mi. of sanitary and combined
sewer
The District of Columbia Water and Sewer Authority (WASA) operates a sewer
system that includes combined sewers serving approximately 12,478 acres.
Among its existing CSO controls is the NEBSF, which provides treatment and
disinfection for up to 400 MGD of CSO before discharging to the Anacostia
River.The facility provides mechanical screening followed by three 57 foot
diameter swirl concentrators.The effluent from the swirl concentrators flows
to a mixing chamber where sodium hypochlorite is added, usually at a dose
of 5 mg/L Sodium bisulfite is added at the end of the outfall for dechlorination, usually at a dose of 2 mg/L Flows above 400 MGD
receive no treatment and are discharged through the same outfall as treated flows.
Samples taken during CSO events at the mixing chamber and at the river outfall are analyzed for enterococcus and fecal coliform.
Reported counts range from less than 10 MPN/100 ml to in excess of 250,000 MPN/100 ml.The high numbers are associated with
events in excess of 400 MGD and represent a comingling of treated and untreated CSO.
Annual operating costs for the NEBSF are estimated to be about $230,OOO.This is based on $180,000 for labor and $50,000 for chemicals.
Labor includes two full-time operators,a part-time supervisor,and other part-time support for cleaning and maintenance.The facility
discharges on average about 100 times peryear,withan average total volume of approximately 1,500 MG.
Contact:Mohsin Siddique, CSO Control Program Manager, DC WASA
BIRMINGHAM, AL
UV Disinfection at Peak Flow WWTP
Responsible Agency: Jefferson County
Environmental Services Division
Population Served: 376,000
Service Area: Not Available
Sewer System: 3,100 mi. of sewer
The Jefferson County Environmental Services Division owns and operates
nine wastewater treatment facilities, collecting and treating wastewater from
the City of Birmingham and some 20 neighboring municipalities.These nine
plants, along with about 658 miles of separate sewers, serve an approximate
population of 376,000 at an average daily flow of 97 MGD.The Village Creek
WWTP has at times received peak flows greater than ten times its annual
average flow (in excess of 400 MGD versus an average of 40 MGD). Currently,a
350 MGD peak excess flow treatment facility is under construction.
The Village Creek Peak Flow Wastewater Treatment Plant (PFWWTP) includes a pump station with 360 MGD capacity, 20 surge
basins with surface aeration for mixing (total capacity of 90 MG), granular monomedia deep bed filters with 350 MGD capacity, UV
disinfection,and a 24-megawatt generating facility (primarily to power the pump station and UVJ.The entire facility is scheduled to
be completed in the summer of 2003.
The Village Creek PFWWTP uses a UV disinfection system with a total of 2,688 lamps and has a peak power requirement of 7,526 kW.
The total installed cost of the UV facility at Village Creek is estimated to be $13 million; the cost for the UV equipment is approximately
$10.7 million. Operating costs are not available.
Contact: Harry Chandler, Assistant Director, Environmental Services, Jefferson County
TMT-23
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Chlorine Disinfection at Acacia Park
Responsible Agency: Oakland County Drain The Office of the Oakland County Drain Commissioner (OCDQ
Commissioner currently operates three CSO retention basins in southeastern
Population Served: 4,500 Michigan, all of which provide treatment and disinfection of
Service Area: 1.28 sq. mi. flows that exceed their storage capacity. The Acacia Park CSO
Sewer System: Not Available Retention Treatment Basin (RTB) is a 4 MG basin that serves
a combined area of approximately 816 acres. Disinfection is
by sodium hypochlorite, which is stored at about 6 percent to
reduce the rate of degradation during storage.The feed system
is designed to provide a dose of 10 mg/L at a CSO flow rate of 426 MGD.The hypochlorite is fed at the discharge of the influent
pumps, which provides sufficient mixing. Dechlorination is not currently provided at this facility.
Extensive monitoring of the basin performance was conducted during a three-year demonstration period from 1997-1999 (Johnson
etal. 2000).The disinfection target was a fecal coliform count of less than 400 #7100 ml at a total residual chlorine (TRQ level of 1.0
mg/L.The purpose of the TRC goal is to ensure that a sufficient dose of chlorine is delivered to the basin.
Five of the nine events monitored had average TRC levels above 1.0 mg/L, and the fecal coliform target was met in four of these five
events. The four events with average TRC levels less than 1.0 mg/L did not meet the fecal coliform target. Low TRC was generally
attributed to sodium hypochlorite solutions being weaker than anticipated either because of degradation or inaccurate dilution of
the chemical.
Annual operating costs for the Acacia Park facility are estimated to be $120,OOO.This includes $58,600 for labor, $24,800 for energy and
utilities, $26,000 for chemicals,and $10,500 for laboratory and other services.These costs reflect some additional expense associated
with startup, testing, and performance evaluation. Over the three-year demonstration period, the facility captured approximately
60 percent of the flow it received; that is, treated overflows represented 40 percent of flow into the facility.The total volume of flow
into the facility was estimated at 146MG,with 88 MG retained and returned to the sewer system and 58 MG treated and discharged.
Overflows occurred on average four to five times per year, and ranged in volume from 0.13-17 MG.
Contact: Dan Mitchell, Hubbell, Roth, and Clark, Michigan
BREMERTON, WA
Responsible Agency: City of Bremerton
Population Served: 40,000
Service Area: 10 sq. mi.
Sewer System: 250 mi. of sewer
UV Disinfection at CSO Treatment Facility
The City of Bremerton has recently constructed a CSO treatment facility that
uses high-rate clarification, followed by UV disinfection, to treat flows up to
45 MGD.The facility uses a medium-pressure, high-intensity UV system that
employs a total of 90 bulbs. A 500 kilowatt generator is located on site to supply
power to the UV system as well as pumps, mixers, and other appurtenances.
The clarification system uses a polyaluminum chloride coagulant, which was
selected over the equally effective ferric chloride to avoid UV interferences by residual iron.The primary reason for choosing UV over
chlorination was to avoid the degradation of hypochlorite between discharge events, which are estimated to occur approximately 20
times per year. Bremerton installed a UV system at a cost of about $600,000 to disinfect CSO discharges.The annual operation cost for
the entire facility is estimated to be about $50,000; UV power costs and bulb replacement are a portion of this.
Contact: John Poppe, Wastewater Division Manager, City of Bremerton
TMT-24
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Treatment Technologies: Disinfection
COLUMBUS/GA Chlorine and UVDisinfection Demonstration Project
Responsible Agency: Columbus Water
Works
Population Served: 186,000
Service Area: 95 sq. mi.
Sewer System: 8.1 mi. of combined sewer
Columbus Water Works (CWW) operates a sewer system and treatment plant that
includes 5,200 acres of combined sewer service area. Pilot studies aimed at gathering
more information for controlling CWW's CSOs grew, in part with the aid of an
appropriation from Congress, into the Uptown Park Advanced Demonstration Facility
(ADF).The ADF included vortex separators,compressed media filtration,and chemical
and UV disinfection systems. Chemicals evaluated included sodium hypochlorite,
chlorine dioxide and peracetic acid; vortex separators were used as contact chambers
for chemical disinfection.The UV system used medium pressure, high-intensity lamps.
The study demonstrated the challenges to chemical disinfection posed by the variation of chemical oxidant demand in CSO. In
general, no direct relationships were observed between effluent fecal coliform concentrations and CT values based on disinfectant
dose alone. Useful relationships were obtained, however, when CT values were normalized by both CSO ammonia concentration and
the mass of chemical oxygen demand (COD) removed.The results were used to develop control algorithms for disinfectant dosing that
are based on CSO influent conditions, rather than relying on residual chlorine measurements that can be difficult to obtain reliably
under rapidly changing flow conditions.
UV disinfection performance was characterized by the inactivation of E.coli. The inactivation increased with increasing UV dose, which
was calculated as the product of applied lamp power, UV percent transmittance, and contact time. UV transmittance of the filtered
effluent was typically less than 60 percent, and at levels less than 40 percent, effluent bacteria increased by an order of magnitude
(from hundreds to thousands). In contrast, the unfiltered CSO UV transmittance was as low as 20 percent.
Capital and operating costs were developed for an optimized treatment train consisting of screening and grit removal, vortex
separation,filtration,and combined chemical and UV disinfection. UV and chlorine disinfection/dechlorination accounted for about 28
percent of the capital cost and 39 percent of the operating cost. Capital costs for a treatment system designed for 63 percent removal
ofTSS were estimated to be approximately $10,000 per acre of combined sewer service area; annual operating costs were estimated
to be about $163 per acre. Designing the system for 80 percent removal of TSS increased the capital cost nearly threefold, with annual
operating costs doubling.
Contact: Cliff Arnett, Columbus Water Works
TMT-25
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Report to Congress on the Impacts and Control ofCSOs and SSOs
References
Acher, A., et al. 1997. "Ecologically Friendly Wastewater
Disinfection Techniques." Water Research. 31(6):1398-1404.
Camp, Dresser & McKee (COM). 1997. "Spring Creek
AWPCP Upgrade - CSO Disinfection Pilot Study - Final
Report." Location: Publisher.
Curtis, M. and K. Blue. City ofUnalaska Ultraviolet
Disinfection of a Primary Effluent. Conference proceedings
at Water Environment Federation WEFTEC New Orleans,
LA, 1999.
EPA Office of Research and Development. 2002. CSO
Disinfection Pilot Study: Spring Creek CSO Storage Facility
Upgrade. EPA 600-R-04-077.
EPA Office of Water and Office of Ground Water and
Drinking Water. 1999. Alternative Disinfectants and
Oxidants Guidance Manual. EPA 815-R-98-009.
Johnson, C. E., et al. Operating Experience with Large
CSO Control Facilities. Conference proceedings at Water
Environment Federation WEFTEC Anaheim, CA, 2000.
Matson, B., et al. Meeting SSO Requirements with a High
Rate Process Train: Pilot Results Lead the Way. Conference
proceedings at Water Environment Federation WEFTEC
Chicago, IL 2002.
Poppe, John. Wastewater Division Manager, City of
Bremerton, WA. Interview by Limno-Tech, Inc., December
2002. Ann Arbor, MI.
Siddique, Mohsin. CSO Control Program Manager, District
of Columbia Water and Sewer Authority. Interview by
Limno-Tech, Inc, December 2002. Ann Arbor, MI.
Tetra Tech MPS. Interview by Limno-Tech, Inc., December
2002. Ann Arbor, MI.
White, G.C. 1999. Handbook of Chlorination and Alternative
Disinfectants. 4th Ed. New York: Wiley and Sons, Inc.
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
TMT-26
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RIPTION
Treatment T
les
Vortex Separators
Overview
Vortex separators are designed to concentrate and remove
suspended solids and floatables from wastewater or storm
water. Sometimes referred to as swirl concentrators, vortex
separators use centripetal force, inertia, and gravity to
provide treatment. The vortex design induces solids to
settle out into a sump; floatables are captured by screens.
In combined sewer systems (CSSs), vortex separators are
used at hydraulic control points (regulators) to separate
combined sewage into a small volume of concentrated
sewage and solids, and a large volume of more dilute
sewage and storm water runoff. The concentrated sewage
is typically conveyed to a wastewater treatment plant
(WWTP) for treatment, and the dilute mix is discharged
directly to a receiving water. This discharge may or may not
be disinfected. In storm water systems, vortex separators are
used to capture solids and floatables at storm water outfalls.
In storm water applications, captured material needs to be
cleaned out and removed for disposal on a regular basis. In
general, vortex separators are not used to provide treatment
at remote locations in sanitary sewer systems (SSSs). The
focus of this technology description is the use of vortex
separators for controlling wet weather discharges from
CSSs.
Vortex separators are flow-through structures that usually
have one inlet and two outlets: one for concentrated sewage
and solids, and one for more dilute sewage. Different
vendors provide different design features to optimize
liquid-solid separation and pollutant removal. Many vortex
separators use screens and baffles to collect floatables.
Floating sorbent materials are also used in some designs
to capture oil and grease. The range of size and capacity of
vortex separators is quite large.
A simple diagram of a vortex separator is shown in Figure
1. The basic operation of a vortex separator is as follows:
• Excess wet weather flow enters the separator
tangentially through an inlet pipe.
Velocity causes flow to move through the separator in a
circular path, forming a vortex.
Inertia, gravity, and centripetal forces cause the heavier
solid particles to move to the center and bottom of
the swirling flow. Clearer water rises and discharges
through the outlet.
The concentrated sewage, including heavier solids and
debris, becomes underflow and is discharged through
a foul sewer outlet at the bottom of the separator and
routed to a WWTP.
Overflow to
recieving water
To wastewater
treatment plant
Figure 1. Simplified diagram of a vortex separator.
When the separator is full, the more dilute and clarified
effluent is discharged through an overflow outlet at the top
of the separator and conveyed to local receiving waters.
At the end of an event, as excess wet weather flows subside
and the water level in the separator drops below the level of
the overflow outlet, the separator ceases to discharge to the
receiving water.
Disinfection of the discharge from vortex separators
is sometimes added for public health reasons (Boner
et al 1995). Sodium hypochlorite can be injected into
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Report to Congress on the Impacts and Control ofCSOs and SSOs
the separator basin, allowing the wet weather flows to
be disinfected as the solids are removed. Chlorinated
discharges may also need to be dechlorinated to prevent
toxicity. Discharges from a vortex separator can also be
treated using ultraviolet (UV) disinfection. If the separator
design includes a sump to capture solids, the solids should
be removed in advance of the next wet weather event.
Some designs enable buoyant floatables to be skimmed
from the dilute overflow and mixed with the underflow for
conveyance to the treatment plant.
Key Considerations
Applicability
Vortex separators provide a modest level of treatment
for a modest cost. In CSS, they can be used as a "stand-
alone" CSO control, or in conjunction with other controls.
When used on their own, they are useful in controlling
suspended solids and floatables and in reducing pollutants
associated with solids, such as metals bound to sediments.
Their ability to reduce floatables in CSO discharges is
valuable in situations where control of aesthetic impacts
is important to the public. They have limited ability to
reduce the strength of dissolved pollutants or bacteria
unless disinfection is applied in conjunction with vortex
separation. When used in combination with other CSO
controls, the placement of vortex separators is important.
Because they are designed to remove suspended solids
and floatables, vortex separators should not be placed
downstream of other facilities that perform the same
function, such as sedimentation basins or netting systems.
Vortex separators are often retrofitted within CSSs to
provide some level of treatment where none had existed
before. Considerations in implementing vortex separators
include:
• Vortex separators do not require a power source
because the energy of the flowing water is used to
separate the solids. Therefore, the utility of vortex
separation technologies is diminished in situations
where the velocity of wet weather flows is limited.
• Space requirements are minimal relative to storage
units because they separate rather than store sewage.
• Units can range in diameter from 2 feet to more than
40 feet and are typically installed underground.
• Soil conditions and depth to bedrock at potential sites
influence site suitability and construction costs.
• Vortex separators can be either pre-fabricated or built
on-site. They can be constructed of concrete, high-
density polyethylene (HDPE), aluminum, or stainless
steel, depending on the manufacturer.
Advantages
The major advantage of vortex separators is their ability
to remove suspended solids and floatables, which are the
most visible and aesthetically displeasing components of
CSO discharges. Vortex separators begin to separate out
suspended solids and floatables as soon as inflow begins to
move through the unit. Additional advantages include:
• Maintenance requirements are low. Vortex separators
have no moving parts to wear out or break. They can
be allowed to go dry between storms without affecting
performance.
• Vortex separators have a high hydraulic loading
capacity.
• Space requirements at implementation sites are low.
Disadvantages
The principal disadvantage in the use of vortex separators
for CSO control is that they do not eliminate CSOs or
reduce CSO volume; they just reduce the strength of the
CSO discharge with respect to suspended solids, pollutants
associated with suspended solids, and floatables. Other
disadvantages include:
• Removal rates of fine solids and soluble pollutants are
low or negligible in vortex separators.
• Disinfection is difficult because of the large volumes of
excess wet weather flow received by vortex separators,
short contact time for disinfection, and space and
security requirements associated with disinfectants.
• Floatables may be lost during extremely high flows or
in the initial overflow, when the surge of inflow could
carry them around and over the baffles and weirs
designed to remove them.
• Vortex separators with sumps require periodic cleaning
to achieve optimal removal performance.
Cost
The performance of vortex separators with respect to
pollutant removal is based on the difference in pollutant
load, not volume, that is discharged to a receiving
water over time, with and without a vortex separator.
Performance is directly related to the nature of the solids
and floatables in the influent wastewater, as well as the
influent concentrations and loading rates. Qualitatively,
vortex separators can be expected to provide "good"
removal of heavier particles and floatables and "fair to
poor" removal of lighter weight materials such as oil and
grease, nutrients, and colloidal material (WERF 2002).
Some common performance characteristics are as follows:
• Vortex separators perform better for concentrating
larger or heavier suspended solids for treatment
TMT-28
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Treatment Technologies: Vortex Separators
than smaller or lighter suspended solids. Removal of
dissolved solids or dissolved fractions of pollutants is
negligible.
• Site specific design matched to particle size and settling
velocity profiles of suspended solids is essential to
optimize performance.
• Floatables capture decreases as hydraulic loading
increases.
Available data for basic vortex separation suggest widely
varying performance, with total suspended solids (TSS)
removal ranging from five percent to 60 percent (EPA
1996; Boner et. al. 1995; WERF 2002). The higher removal
rates are comparable to primary clarification, but can
be achieved in a vortex separator that is one-fourth the
volume and one-fifth the surface area of a conventional
sedimentation basin (Boner et. al. 1995). TSS removal
rates of up to 80 percent have been achieved when units
are operated at one-fourth of the hydraulic capacity (Larry
Walker Associates 1999). In a survey of vortex separator
performance documented by Moffa (1997), removal
efficiencies were shown to vary substantially from storm-
to-storm, and from one facility to another.
Additional vortex separation performance information for
other pollutants is as follows:
• BOD5 removal rates have ranged from 20 percent and
79 percent in laboratory studies (Moffa 1997). Actual
BOD5 removal rates for two storms in Columbus, GA,
reached 55 percent (Boner et. al. 1995). Data for the
Northeast Boundary Swirl Facility in Washington, D.C.,
indicate BOD5 removal efficiencies of up to 28 percent
(WERF 2002).
• Manufacturer laboratory tests show that vortex
separators can remove 80 percent of oil and grease;
however, no data are available for oil and grease
removal rates under actual, full-scale operating
conditions.
• UV disinfection of vortex discharges can achieve a
90-99 percent reduction in the concentration of fecal
coliform bacteria (WERF 1994).
Costs for purchasing a basic vortex separator range from
approximately $8,000 for a 1.8 MGD unit to $40,000 for
a 16 MGD unit. Installation costs typically from 25-50
percent of the purchase costs (Larry Walker Associates
1999). A summary of products from various manufacturers
with ranges in available hydraulic capacities and costs is
presented in Table 1.
Maintenance costs for vortex separators vary depending on
cleaning frequency, travel distances, and disposal costs for
captured solids and floatables.
Table 1. Comparison of vortex separation products and costs.
Product
(Manufacturer)
Continuous Deflective Separation (CDS Technologies]
Downstream Defender (/-/. /. L Technology, Inc.)
V2B1 (KistnerConcrete)
Vortechs Storm WaterTreatment System (Vortechnics)
Available Hydraulic
Capacity Sizes (MGD)
Purchase Costs
$9,600-$332,500
$10,300-$26,000
$8,000 - $40,000
$10,500- $40,000
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Implementation Examples
RANDOLPH,VT
Vortex Separator Used to Treat CSOs
Responsible Agency: Burlington Main
WastewaterTreatment Facility
Population Served: 37,712
Service Area: Not Available
Sewer System: 100 mi. of sewer
The Burlington Main Wastewater Treatment Facility (WTF) treats municipal
wastewater from the city's CSS and discharges treated flow through an outfall into
Lake Champlain.The WTF also has a CSO treatment system on-site which includes
vortex separation,mechanical screening,and disinfection; the system was installed
in the early 1990s.The CSO treatment system is designed to handle wet weather
instantaneous flows greater than 11 MGD, but not exceeding 86 MGD.
The vortex separation process, combined with the capacity of the treatment plant, is designed to provide a relatively high level
of treatment for the "first flush" generated during the early stages of storm events that usually contains the highest pollutant
concentrations. Chemical disinfectant is added to the CSO flow prior to and after treatment by the vortex separator.The concentrated
underflow from the vortex separator, approximately 2 MGD, is diverted to the WTF for full treatment. During wet weather events
when the instantaneous storm flow rate exceeds 75 MGD, ultrasonic sensors allow flows to bypass the vortex separator. According to
self-monitoring reports from January 1995 through December 1999, the CSO system was activated an average of 32 times per year,
13 times on average during the"beach season" of June through August.
More information at http://www.dpw.ci.burlington.vt.us/
COLUMBUS, GA
Notional Demonstration Project
Responsible Agency: Columbus Water Works The Co|umbus css extends over the o,d downtown area draining into the
Population Served: 186,000 Chattahoochee River. Prior to CSO control, elevated levels of fecal coliform bacteria
Service Area: 2,400 sq. mi. and visible sewage debris often plagued the Chattahoochee. Columbus began to
Sewer System: Not Available implement CSO controls in 1995, including construction of two water resource
facilities (WRFs). One of the WRFs, in Uptown Park, also serves as a national CSO
technology testing facility used to demonstrate and evaluate alternative methods
of CSO pollutant removal and disinfection.
A five year CSO testing program was conducted at the Uptown WRF to analyze the performance, operation and maintenance (O&M),
costs, and applications of CSO treatment technologies, including vortex separators. At this facility, Columbus installed six vortex
separators, each 32 feet in diameter, with a conical ring bottom where grit and concentrated solids are removed. All six vortex vessels
start empty and fill with CSO flow as CSS capacity is exceeded.The vessels have no moving parts.The vortex vessels serve as storage for
small events,pollutant reduction during medium events,and grit removal and chemical disinfection forall events.Chemical disinfectant
is added once the vortex vessels are full. For loading rates of 5 gallons per minute per square foot (gpm/sf) of surface area, the vortex
separators functioned similar to a primary clarifier. For loading rates above 5 gpm/sf, however, the removal of pollutants was reduced
to zero except for grit and oil and grease.The study also found that the use of vortex separators in combination with media filters was
an effective treatment method in terms of load reduction and cost.The annual O&M for the vortex separators is estimated at $16,320,
which is about 7 percent of the total O&M costs at the Uptown ParkWRF.The capital cost of the vortex separators was $4.8 million.
Contact: Cliff Arnett, Columbus Water Works
TMT-30
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Treatment Technologies: Vortex Separators
References
Boner, M. C., et. al. 1995. "Modified Vortex Separator and
UV Disinfection for Combined Sewer Overflow Treatment."
Water Science Technology. 31: 263-274.
EPA Office of Wastewater Management, Municipal
Support Division and National Risk Management Research
Laboratory (Cincinnati) Water Supply and Water Resources
Division. 1996. Assessment of Vortex Solids Separators for the
Control and Treatment of Wet-Weather Flow. EPA 832-B-96-
006.
Larry Walker Associates, Inc. 1999. "Investigation of
Structural Control Measures for New Development.
Prepared for the Sacramento Storm water Management
Program." Retrieved December 12, 2002.
www.sacstormwater.org/const/manuals/pdf/scm99_
scm99.pdf
Moffa, P.E. (Ed.). 1997. Control and Treatment of Combined
Sewer Overflows. 2nd ed. New York, NY: Van Nostrand
Reinhold.
Water Environment Research Federation (WERE). 1994.
Optimization of Vortex Separator Removal Efficiencies for
CSO Treatment. Prepared by Boner, M. C., et al. Alexandria,
VA: WERE Project 92-TCR-2.
WERE 2002. Best Practices for Treatment of Wet Weather
Wastewater Flows. Prepared by Brashnear, R., et. al.
Alexandria, VA: WERE. Project OO-CTS-6.
Inclusion of this technology description in this Reportto
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
TMT-31
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RIPTION
Floatables Control
Overview
Solids and floatables are the trash, debris, and other visible
materials that are discharged when sewers overflow. In
sanitary sewer systems (SSSs), solids and floatables are
generally limited to human waste and sanitary products
that are flushed down a toilet. In combined sewers systems
(CSSs), solids and floatables can also include litter and
detritus that accumulates on streets and parking lots that
are washed into storm drains during rainfall events. The
presence of solids and floatables in receiving waters causes
aesthetic impacts that can threaten wildlife, cause beach
closures, and pollute recreational areas.
Floatables control technologies are principally applied in
CSSs because of the recurring nature of CSOs. They are
also used to control solids and floatables in urban storm
water discharges from separate storm water systems.
Floatables controls are most often designed to lessen
aesthetic impacts that affect recreational uses. Water
quality benefits from floatables controls, if they occur,
are secondary. The CSO Control Policy recognized the
importance of controlling solids and floatables by including
it as part of the nine minimum controls. Floatables controls
can be grouped into three categories:
• Source controls work to prevent solids and floatables
from entering the sewer system.
• Sewer system controls work to keep solids and floatables
in the sewer system, so that they can be collected and
removed at strategic locations or transported to a
wastewater treatment plant.
• End-of-pipe controls work to capture solids and
floatables as they are discharged from the sewer system.
Source Controls
Source controls collect solids and floatables before
they enter the sewer system. Two of the most common
source controls are street sweeping and catch basin
modifications. Street sweeping is a pollution prevention
activity that removes litter, debris, dirt, and other
floatables materials from streets and other paved
surfaces before it can be washed into a CSS during
wet weather events. Paved surfaces can be swept using
manual, mechanical, or vacuum sweepers (WEF 1999).
The degree of floatables control achieved by street
sweeping is influenced by the frequency of cleanings,
local climate, and parked vehicle control (EPA 1999b).
Catch basins are the surface-level wells or chambers
that serve as an entrance to CSSs and separate storm
water systems for street runoff and overland flow. Catch
basins are designed to trap grit and solids before they
enter the sewer system (Moffa 1997). There are several
modifications that can be made to catch basins to
improve the capture of solids and floatables. Inlet grates
installed at the entrance to the catch basin can reduce
the amount of street litter and debris that enters the
catch basin. If floatables enter the basin through these
grates, they can be collected in colander-like structures
called trash buckets installed beneath the grate.
Other catch basin modifications, such as hoods and
submerged outlets (Figure 1), modify the connection
between the catch basin and the CSS to trap floatables
Figure 1. Typical hood design in a catch basin.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
in the catch basin. Submerged outlets are located below
the elevation of the sewer system and are connected by
a riser pipe. Hoods are vertical cast iron baffles installed
over the outlet pipe in the catch basin.
Collection System Controls
Collection system controls are designed to keep solids
and floatables in the sewer system so that they can
be collected and removed at strategic locations or
transported to a wastewater treatment plant. Screens,
baffles, and in-system netting are types of collection
system controls.
Screens can be installed near CSO outfalls or at other
strategic locations in the CSS. Screens trap floatables
behind metal bars or mesh, allowing wastewater to
pass through. Screen openings typically range in size
from 0.1 inch to 6 inches. The type of screen and size of
openings determine the amount and size of floatables
captured (EPA 1999c). Major categories of screens
include:
• Bar screens or trash racks with openings greater
than 1 inch;
• Coarse screens with 0.25-1 inch openings; and
• Fine screens with 0.001-0.25 inch openings.
The nature and quantity of floatables in wet weather
flows makes them likely to clog fine screens therefore
their utility maybe limited. Screens are usually set 0-30
degrees from vertical and may be cleaned manually or
mechanically.
Baffles can be installed at flow regulators in CSSs or at
outlets from storage facilities. Baffles are commonly
made from concrete beams, steel plates, wood, or
plastic, and, as shown in Figure 2, extend from the top
of the sewer to just below the regulating weir. As flow
rises in the CSS or storage facility, water passes under
the baffle and over the regulator to the CSO outfall.
Most floatables are trapped behind the baffle and
remain in the CSS where they are transported to the
treatment plant (EPA 1999a).
In-system netting is installed at strategic locations
in the sewer system in concrete vaults, often near
regulators in the outfall pipe. One or more nylon mesh
bags are supported by a metal frame. Netting system
design, including the aperture of the mesh nets, is based
on the size and types of floatables targeted for capture
and the anticipated volume of flow. Wet weather
flows carry floatables into the nets, which are replaced
periodically (EPA 1999a).
Figure 2. Baffle placement at a CSO regulator.
End-of-Pipe Controls
End-of-pipe controls use netting systems or
containment booms and skimmer vessels to capture
floatables in the receiving water after they have been
discharged from the sewer system.
End-of-pipe netting systems consist of an in-water
containment area that funnels CSO discharges through
a series of nylon mesh bags attached to a modular
pontoon structure. Also referred to as a floating netting
system, nets are located a short distance from the CSO
outfall, allowing the floatables to rise to the water
surface after the discharge mixes with the receiving
water (EPA 1999a). As with in-system nets, the size of
the mesh net used will depend on the volume and type
of floatables targeted for capture (EPA 1999a). After the
nets become full, they are removed and disposed.
Containment booms can be located in a receiving water
downstream of one or more CSO outfalls. The booms
are floatation structures with a suspended curtain
that captures buoyant materials. Booms are typically
anchored to the shoreline and bottom of the waterbody.
They may also be designed to absorb oils and grease.
The size of the boom is determined by the volume of
floatables expected from a design storm event. After
a storm, floatables and other debris trapped by the
boom will need to be removed with a vacuum truck,
manually, or using a skimmer vessel (EPA 1999a).
Skimmer vessels are boats designed to gather
floatables in lakes, harbors, or bays, and can be used in
conjunction with containment booms. Skimmer vessels
capture floatables using either a capture plate located at
the bow of the boat that collects debris on a conveyor
TMT-34
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Treatment Technologies: Floatables Control
belt system or by lowering large nets into the water.
Skimmer vessels may require companion equipment to
transport the debris for land disposal.
Key Considerations
Applicability
Source Controls
Street sweeping can be performed on any paved surface
and is often already part of a municipality's standard
activities. In colder climates, sweeping during the
spring snow-melt reduces the road salt and sand load
delivered to the CSS (EPA 2002). The optimal timing
between street sweepings ranges from a few weeks to
a month based on the amount of debris present on
the street. The sediment removal efficiency of street
sweeping as a function of the time between sweeps is
illustrated in Figure 3.
80%
20 30 40 50
Weeks Between Sweeping
Figure 3. Cumulative sediment removal by street sweeping.
Catch basin modifications increase the capture of
solids and floatables, which often necessitates more
frequent maintenance. Without proper maintenance,
catch basin performance can be compromised. The
more solids and floatables that are collected and held
in a catch basin, the less effective the basin becomes
at trapping additional material. A catch basin filled
with solids and floatables can have the unintended
consequence of blocking the inlet to the sewer system.
Catch basin cleaning frequencies vary greatly, with
some municipalities performing maintenance annually
and others scheduling catch basin cleaning once every
five to six years. Often, individual basins are cleaned
as specific needs arise, such as citizen complaints
of localized street flooding. In general, a cleaning
frequency of at least twice per year maintains the
effectiveness of catch basins for pollutant removals
(Moffa 1997). Manual and vacuum cleaning are two
methods available to remove accumulated debris from
catch basins (EPA 1999b).
Collection System Controls
Screens can be used effectively for CSO control because
they capture a significant amount of the floatables
contained in CSO discharges. Removal efficiencies
are tied closely to the spacing between bars or mesh
aperture and can range from 25-90 percent of the
total solids. The effectiveness of screening is reduced
significantly by the presence of oil and grease in the
flow (EPA 1999a). Many screens are self-cleaning
but regular maintenance is required to ensure their
effectiveness. Finer screens have higher removal
efficiencies, but are more susceptible to clogging and
tearing and may require maintenance after every
CSO event. Additional information on fine screens is
presented in the "Supplemental Treatment Technology
Description" included in Appendix B of the Report to
Congress on the Impacts and Control of Combined Sewer
Overflows and Sanitary Sewer Overflows.
The design of existing regulators or storage facilities
will determine the effectiveness of baffles, as well as
the cost to retrofit the structure. In some retrofits, the
addition of baffles may restrict access to the regulators
making maintenance more difficult. When a new
structure is installed, baffles can be included in the
design. Maintenance requirements for baffles are low
compared to other floatables controls, requiring only
occasional cleaning to remove debris and reduce odors.
In-line netting units are widely applicable and can
be adapted to most CSSs (EPA 1999a). Access to in-
system netting is important since the mesh bags must
be inspected after each overflow event and changed
when full. The frequency of bag changing depends on
site-specific conditions, including the frequency and
volume of CSO events and the volume of floatables
in the discharges. Cities report changing the mesh
bags between 12 to 36 times a year. Field tests indicate
netting can provide removal efficiencies of up to 90
percent for floatables (EPA 1999a).
End-of-Pipe Controls
The nature of the receiving water influences the
applicability of end-of-pipe controls. End-of-pipe
netting systems are most suitable for lakes, estuaries,
and tidal waters (EPA 1999a). Netting systems are
sized based on the peak flow expected, the maximum
flow velocity, and the quantity of floatables and other
debris per million gallons of CSO. End-of-pipe netting
systems require a minimum water depth of two feet and
should not be located near heavily traveled waterways.
As described in the discussion of in-line netting
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Report to Congress on the Impacts and Control ofCSOs and SSOs
systems, end-of-pipe systems have relatively high
maintenance requirements.
Site conditions, such as receiving water velocity, should
be considered when evaluating containment boom
design, placement, and anchoring. Although booms
float and can therefore accommodate some fluctuation
in water level, high river velocities and winds may
dislodge them. Furthermore, booms cannot be used
during winter months in waters that are subject to
freezing. Maintenance requirements for containment
booms are moderate relative to other floatables
controls; floatables trapped behind booms will need to
be removed periodically.
Skimmer vessels are used to clean broad areas of
open water. As a result, the floatables and other debris
collected are likely to come from a variety of sources
including CSOs, separate storm water systems, and
upstream sources. Ice and high wind can impede
skimmer vessel navigation and the collection of
floatables. It is also important to be aware of minimum
depth and clearance height requirements specific to
each vessel (EPA 1999a).
All end-of-pipe systems can create temporary unsightly
conditions near CSO outfalls, and therefore, may be
inappropriate in areas with waterfront development.
Cost
A summary of cost and maintenance considerations, as well
as the relative capture efficiency, for each of the floatables
control technologies is presented in Table 1. Representative
costs from actual applications are presented in Table 2.
Table 1. Comparison of floatables control technoloqies.
Category
Source Controls
Collection System Controls
End-of-Pipe Controls
Technology
Street Sweeping
Catch Basin Modifications
Screens and Trash Racks
Baffles
In-System Netting
End-of-Pipe Netting
Containment Booms
Skimmer Vessels
Capital Cost
H1
L
M
M
M
M
H
H1
Maintenance
Requirements
M
M
L
L
H
H
M
M
Floatables Capture
Efficiency
L
M
M
M
H
H
H
M
Assumes program would require vehicle/vessel purchase.
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Treatment Technologies: Floatables Control
Table 2. Cost comparison of floatable control technologies.
Category Technology
Source Controls Street Sweeping
Costs depend on frequency of cleaning, volume of litter, enforcement of
parking regulations,and other labor costs.1
Contracted street sweeping costs $130-$150 per curb mile.2
Plymouth Township, Ml, swept 511 miles of curb at a cost of $68 per
mile.2
Vacuum sweeping trucks cost between $150,000-$200,000 depending
on the material holding capacity. Maintenance costs range from
$12,500-$ 15,000 per truck peryear.1
Collection
System Controls
Screens and Trash Racks
Baffles
Catch Basin Modifications
In-Line Netting
Cost for screens depends on the size of the screen, the means of
cleaning, construction materials,flow rate,and whether construction
is new or a retrofit. Costs can range from $40,000 to $9 million per
screen.4
Seattle,WA, installed 25 MGD rotary screen for approximately $1.7
million.4
Steel or aluminum curtains are usually used for retrofits at an average
cost of less than $10,000 each.3
Costs range from $65-$100 per basin.1
Trash buckets can cost an average of $100 per basin to install.3
Contracted catch basin cleaning costs range from $50-$ 170 per hour.3
Netting system costs range from $75,000-$300,000 per site.5
Operations and maintenance (O&M) costs for changing full nets are
$1,000 per site.3
End-of-Pipe
Controls
End-of-Pipe Netting
Containment Booms
SkimmerVessels
Netting system costs range from $25,000-$300,000 per site.5
Installation costs for booms range from $100,000-$ 150,000 per site.3
O&M costs for changing full nets are approximately $1,000 per site.3
Skimmer vessels cost between $300,000-$700,00 depending on vessel
features.3
O&M costs can range between $75,000-$ 125,000 peryear per boat.3
A pier conveyor to remove debris from the vessel can cost $37,000.6
1 EPA 1999b
2 Ferguson 1997
3 EPA1999a
4 EPA 1999c
5 EPA 1999d
6 Shenman 2003
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Implementation Examples
PORTLAND, ME
Street Sweeping
Responsible Agency: City of Portland Public The Qty of Port|and Sweeping Program sweeping crews work five nights a
Works Department week from late March to the beginning of December. During the sweeping
Population Served: 190,000 season, the crews routinely sweep a total of 480 curb miles.The city tries
Service Area: 17.7 sq. mi. to sweep each street at least once a month and twice a month if the street
Sewer System: Not Available is more heavily trafficked. One section of town has daytime sweeping at
the request of the area residents. A parking program is in effect in the
downtown portion of the city and an odd/even parking program is used
in residential areas.The sweepers are effective in removing debris from the streets of Portland. It is estimated that during the spring
street cleaning, up to 9,000 tons of sand and salt are caught before entering the sewer system.
The sweeping fleet consists of eight sweepers with an annual maintenance budget of $125,000. The total annual budget of the
program is $412,000 or $51,500 per sweeper.
More information athttp://www.ci.portland.me.us/publicworks/street.htm
NEW YORK CITY, NY
City-Wide Floatables Study
Responsible Agency: New York City Department of
Environmental Protection
Population Served: 7.6 million
Service Area: 297 sq. mi.
Sewer System: 4,200 mi. of combined sewer, 1,800
mi. of sanitary sewer
New York City studied street sweeping extensively in the early 1990s, as
part of a city-wide effort to reduce CSO discharges of floatable material
to New York Harbor (NYCDEP 1995). The study found that the primary
sources of floatables were trees, littering, and spilled trash receptacles.
Most debris was found within 3.5 feet of the curb. As shown in the table
below, plastics were the most prevalent floatable material by volume.
Enhanced mechanical sweeping
within a 450-acre study area (increased from two times per week to six times per week)
produced a 42 percent reduction in floatables on an item count basis, and a 54 percent
reduction on a weight basis. Using a city-wide model, it was estimated that street sweeping
twice per week would reduce floatables loadings to New York Harbor by 29 percent from
current levels,and that increasing the frequency to three times per week would bring the total
reduction in floatables to 49 percent.
In addition to street sweeping, the city has implemented various other floatables control
practices. The city also retrofitted numerous catch basins with hoods. NYCDEP has installed
23 containment booms near CSO outfalls. Once floatables are collected by the containment
booms, they are removed using the city's fleet of skimmer vessels. The city operates four
skimmers designed for smaller tributary streams and one designed for open water conditions.
Some areas have also been equipped with end-of-pipe netting systems, including the Fresh
Creek outfall, one of the city's largest. Studies have shown that the Fresh Creek net has a
capture efficiency of 90-95 percent.
Type of
Material
Plastic
Glass
Metal
Styrene
Cloth
Paper
Wood
Misc
Rubber
Volume of
Floatables (%)
56
12
7
7
6
5
4
2
1
Program costs include $6.5 million to purchase and engineer the containment booms/nets; $6.8 million to purchase and operate the
skimmer vessels; and $6.7 million to purchase 41 catch basin cleaning trucks or $164,000 per truck.
More information athttp://home.nyc.gov/html/dep/html/float.html
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Treatment Technologies: Floatables Control
NORTH BERGEN, NJ
Responsible Agency: North Bergen Municipal Utilities
Authority
Population Served: 48,000
Service Area: 1.8 sq. mi.
Sewer System: Not Available
CSO Floatables Control Facilities
In 1999, North Bergen installed numerous solids and floatables control
technologies, including a mechanical screen bar, four in-system netting
systems, and five end-of-pipe netting systems. An Army surplus boom
truck was purchased for net removal. A dump truck then transports
the nets to the wastewater treatment plants, where the floatables are
disposed of with the screenings taken from flows entering the plant. A
portable vacuuming system is available to remove fine solids.
Replacement of the nets depends on the physical characteristics of the CSS upstream of the netting system. The in-line nets in
relatively fiat areas of the sewer system collect more silt and grit than those downstream of areas with steeper terrain. Changing the
nets at a single location usually takes two hours, but can take up to four hours if the site must be vacuumed. The least active CSO
facility is serviced four times a year, whereas the most active is serviced an average of once per month. A total of 90 tons of floatables
were collected between 1999-2002.
The actual construction cost for the CSO facilities was $3.3 million. Supporting equipment such as the boom truck and vacuum unit
cost $80,000; it is estimated that annual operation and maintenance costs are $57,373.
Contact: Frank Bruno, Maintenance Supervisor, City of North Bergen
BALTIMORE, MD
Keeping Inner Harbor Clean
Baltimore's Inner Harbor has become a symbol of success for waterfront
revitalization efforts around the country.With more people visiting the harbor,
it is important to remove the
debris and trash discharged
into the harbor from the
^ ~~T^^^ Vk»- • -* ^^^K,
u
Responsible Agency: Department of Public
Works, Bureau of Water and Wastewater
Population Served: 1.8 million
Service Area: Not Available
Sewer System: 3,100 mi. of sewer
water systems. In 1988, the
city purchased its first skimmer vessel and currently maintains a fleet of four boats.
The original skimmers were made of machine steel, which have been refurbished
using stainless steel because of the brackish nature of the harbor. The boats remove
floatables,such as styrofoam cups and soda bottles,as well as large and unusual items,
such as refrigerators. Once the floatables are collected, they are off loaded using a
pier-conveyor into dumpsters for later disposal. Patrolling 25 miles of coastline, the
skimmers collect approximately 394 tons of floatables per year.The city has seen marked improvement in the appearance of the water
in Inner Harbor with the use of the skimmer vessels. Over the years, Baltimore has purchased skimmer vessels of varying capacity; costs
for individual boats have ranged from $200,000 to over $500,000.
Contact: Tom Finnerty, Manager, Marine Operations in Baltimore Department of Public Works
United Marine International, LLC
TMT-39
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Report to Congress on the Impacts and Control ofCSOs and SSOs
References
EPA Office of Water. 1999a. Combined Sewer Overflow
Technology Fact Sheet: Floatables Control EPA 832-F-99-008.
EPA Office of Water. 1999b. Combined Sewer Overflow
Management Fact Sheet: Pollution Prevention. EPA 832-F-
99-038.
EPA Office of Water. 1999c. Combined Sewer Overflow
Technology Fact Sheet: Screens. EPA 832-F-99-040.
EPA Office of Water. 1999d. Combined Sewer Overflow
Technology Fact Sheet: Netting System for Floatable Control.
EPA 832-F-99-037.
EPA. 2002. "Pollution Prevention/Good Housekeeping for
Municipal Operations: Parking Lot and Street Cleaning."
Retrieved December 9, 2002. http://cfpub.epa.gov/npdes/
stormwater/menuofbmps/poll_10.cfm
Ferguson, T. et al. 1997. "Rouge River National Wet Weather
Demonstration Project: Cost Estimating Guidelines
Best Management Practices and Engineering Controls."
December 9,2002.
http://www.rougeriver.com/pdfs/stormwater/srlO.pdf
Moffa, P.E. (Ed.). 1997. Control and Treatment of Combined
Sewer Overflows. 2nd ed. New York, NY: Van Nostrand
Reinhold.
New York City Department of Environmental Protection
(NYCDEP). 1995. City-Wide Floatables Study. Prepared by
HydrQual, Inc. Mahwah, NJ: NYCDEP.
Shenman, Lou, President - United Marine International
(UMI). Interview by Limno-Tech, Inc., 2003. Washington,
DC.
Water Environment Federation (WEF). 1999. Prevention
and Control of Sewer System Overflows: Manual of Practice
No. FD-17. Edited by Gray, W et al. Alexandria, VA: WEF.
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
TMT-40
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LOW IMPACT DEVELOPMENT
Porous Pavement
~B •»
Overview
Porous pavement is an infiltration system where storm
water runoff is infiltrated into the ground through a
permeable layer of pavement or other stabilized permeable
surface (EPA 1999a). Porous pavement is considered a low
impact development (LID) control intended to replicate
pre-existing hydrologic site conditions through application
of innovative land planning and engineering design. The
use of porous pavement reduces or eliminates impervious
surfaces, thus reducing the volume of storm water runoff
and peak discharge volume generated on a site. This
curtailment in storm water generation can keep storm
water from entering combined sewer systems and taking up
valuable conveyance and storage capacity. This in turn can
lead to reductions in the volume or frequency of CSOs or
stormwater discharges.
There are several types of porous pavement. Porous asphalt
consists of an open-graded coarse aggregate that is bonded
together by asphalt cement with enough interconnected
voids and sufficient permeability to allow water to infiltrate
through the medium and into the underlying soil quickly
(EPA 1999b).
Porous concrete consists of uniform, open-graded,
coarse aggregate and a lower water-to-cement ratio,
which produces a pebbled, open surface that is roller
compacted. Similar to porous asphalt, porous cement has
interconnected voids that increase its permeability. Porous
pavers are pre-fabricated units, rather than a medium, that
come in two general types: block pavers and grass pavers.
Block pavers consist of interlocking paving materials where
the void areas are filled with pervious materials such as
sand or grass (GSMM 2001). Grass pavers are mats of high
strength plastic grids (often made of recycled materials)
that are filled with gravel. An engineered aggregate material
or a sand and soil mixture is installed beneath the grid and
gravel that allows grass to grow through the gravel to the
surface (TBS 2002). The grids function as mini-holding
ponds where storm water is collected and infiltrated into
the ground.
Installation techniques for porous pavement vary
depending on the type of porous pavement utilized. As
shown in Figure 1, a typical porous pavement system
consists of the following layers: (1) porous pavement;
(2) gravel or coarse sand; (3) filter fabric; (4) reservoir
consisting of 1.5-3 inch diameter stones; (5) gravel or
sand layer; (6) optional filter fabric; and (7) undisturbed
existing soil (EPA 1999b). The water storage capacity of the
stone reservoir beneath the pavement can vary. Perforated
overflow pipes may be installed near the top of the reservoir
to drain excess storm water when the reservoir is full.
\\ \ \ \ \
Porous Pavement (0.5 - 4 ")
\ \ \ \ \ \
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I =1111= i InHktnrhpH pyktinn snil
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= = = IN = 1= MM= MM = IJM = 1111= 111= = 111= =
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Not drawn to scale
Adapted from EPA 1999a
Figure 1. Porous pavement cross-section.
Key Considerations
Applicability
Porous pavement can be used in place of conventional
impervious pavement under certain conditions. Typically,
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Report to Congress on the Impacts and Control ofCSOs and SSOs
porous pavement is most suitable for areas with sufficient
soil permeability and low traffic volume. Porous pavement
is a useful option in urban areas where little pervious
surface exists, provided that the grade, subsoil, drainage
characteristics, and groundwater conditions are suitable
(EPA 1999b). Common applications include: parking lots,
shoulders of airport runways, residential driveways, street
parking lanes, recreational trails, golf cart and pedestrian
paths, and emergency vehicle and fire access lanes. Use of
this technology may be more limited in arid regions with
high wind erosion and cold regions where sand can clog
pores and road salt can contaminate groundwater. Also,
they should not be installed in areas that generate highly
contaminated runoff such as commercial nurseries, auto
salvage yards, fueling stations, marinas, outdoor loading
and unloading facilities, and vehicle washing facilities as
the contaminants could infiltrate into the groundwater
(SMRC 2002). The success of porous pavement applications
depends on several key design criteria including site
conditions, construction materials, and installation
methods. These criteria are further described in Table 1.
Advantages
The primary advantage of porous pavement is a reduction
in the volume of storm water runoff generated on site. By
reducing runoff, porous pavement can reduce the need
for storm water holding systems; allow the use of smaller,
less expensive storm water collection systems; reduce the
need for curbs, gutters, and inlets; maximize waste water
conveyance capacity in combined sewer systems; and reduce
puddling and flooding. A secondary advantage of porous
pavement is that it can remove both soluble and particulate
pollutants such as total phosphorus, total nitrogen, and
heavy metals via natural filtration through the underlying
soil (GSMM 2001). By promoting pollutant treatment,
porous pavements reduce the potential impact of storm
water runoff on local receiving waters.
Disadvantages
A major disadvantage of porous pavement is its tendency
to clog. This can occur as a result of improper design
or construction, but it occurs most commonly from a
lack of maintenance (WMI 1997). Proper maintenance
includes periodic vacuum sweeping followed by high-
pressure hosing to remove sediment from the pores (EPA
1999b). Once clogged, it is very difficult and expensive to
rehabilitate porous pavement, often requiring complete
replacement (EPA 1999a). Another disadvantage is the lack
of expertise of pavement engineers and contractors with
this technology. In addition, some building codes may not
allow installation. Since not all soils are absorptive enough
to provide proper drainage, selection of the technology
must be based on site-specific considerations (TBS 2002).
If the underlying soils are unable to dry out between storm
events, anaerobic conditions may develop which can result
in odors.
Table 1. Design criteria for porous pavement (EPA 1999b).
Design
Site Evaluation
Traffic Conditions
Design Storage Volume
DrainageTime for Design
Storm
Construction
Criterion Guidelines
•Take soil samples by boring to a depth of at least 4 feet below bottom of stone reservoir to check
permeability, porosity, depth of seasonally high water table, and depth to bedrock
• Not recommended on slopes greater than 5% and best with slopes closer to 0%.
• Minimum depth to bedrock and seasonally high water table: 4 feet
• Minimum infiltration rate of 3 feet below bottom of stone reservoir: 0.5 inches per hour
• Minimum setback from water supply wells: 100 feet
• Minimum setback from building foundations: 10 feet downgradient, 100 feet upgradient
• Not recommended in areas where wind erosion supplies significant amounts of windblown
sediment
• Drainage area should be less than 15 acres
1 Use for low-volume automobile parking area and lightly used access roads
1 Avoid moderate to high traffic areas and significant truck traffic
• Highly variable; depends upon regulatory requirements.Typically designed for storm water runoff
volume produced in the drainage area by the 6-month, 24-hour storm event
• Minimum: 12 hours
• Maximum: 72 hours
• Recommended: 24 hours
1 Excavate and grade with light equipment with tracks or oversized tires to prevent soil compaction
Pretreatment
1 Pretreatment, such as bioretention or vegetative swales, recommended for runoff with high levels of
suspended solids
LID-2
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Low Impact Development: Porous Pavement
Cost
Porous pavement can initially cost more than traditional
pavement. The overall cost-effectiveness varies depending
on the site conditions, design requirements, and local
installation and long-term maintenance costs. For porous
asphalt and cement, the raw materials are the same as those
utilized in conventional paving operations, but contractors
may charge higher prices for jobs that involve unfamiliar
formulas or techniques. For porous pavers, the cost can vary
depending on the type utilized. Both grass pavers and block
pavers require a high level of construction workmanship
and expertise to ensure proper installation (GSMM 2001).
The range of costs estimated for basic installation of porous
pavement is summarized in Table 2.
Estimated cost for an average annual maintenance program
for a porous pavement parking lot is approximately $200 per
acre per year (EPA 1999b). This cost estimate assumes four
inspections each year with appropriate vacuum sweeping
and jet hosing. Savings from reduced investments in storm
sewer extensions and costs associated with storm drain
systems (i.e. repair and maintenance) have the potential to
offset the initial costs.
Table 2. Estimated costs for installation.
Paver System
Cost (Sq. Ft) Life Span1
Traditional & Porous Asphalt $0.50 to $1.00 20yrs
Traditional & Porous Concrete $2.00 to $6.50 20yrs
Grass Pavers $1.50 to $5.75 ~20yrs
Block Pavers $5.00 to $10.00 ~20yrs
'Actual values may vary as life span is site specific and maintenance
dependent
Implementation Examples
RENTON.WA
Cesponsible Agency: University of
Washington Center for Urban Water Resources
Porous Pavers Pilot Test
The University of Washington Center for Urban Water Resources untertook a
pilot test of porous pavement in the King County Department of Public Works
building parking lot in Renton, WA. Four types of porous pavement were
installed in sections of the lot: (1) grass pavers with virtually no impervious
surface, (2) plastic grid pavers with grass and gravel in-filling with 60 percent impervious surface, (3) concrete pavers with grass in-
filling with 60 percent impervious surface, and (4) concrete block pavers with 90 percent
impervious surface. There were sections of the parking lotthat were unmodified and thus left
as impervious surfaces (asphalt). Runoff volumes from the porous and impervious sections
were monitored during several storm events in 1996 and in a follow-up evaluation in 2002.
Monitoring during the 1996 study and the 2002 follow-up study showed that the impervious
asphalt surface generated a significant amount of runoff for the majority of precipitation
events. Whereas, minimal storm runoff was generated on the porous pavers as virtually all
precipitation from the observed storms was infiltrated. Therefore, replacing asphalt with
pervious pavement would decrease surface runoff and attenuate peak discharges. The
study found no significant differences in the performance of different types of pavers. The photo: university of Washington
follow-up study in 2002 demonstrated that the porous pavement systems were structurally functional after six years of daily use. The
concrete pavers and block pavers were found to be pa rticularlyrobust,while the grass and gravel pavers did undergo some minor wear.
Contact: Derek B. Booth, Center for Urban Water Resources Management, University of Washington
LID-3
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Report to Congress on the Impacts and Control ofCSOs and SSOs
TAMPA. FL
Florida Aquarium Storm Water Study
Responsible Agency: Florida Aquarium
^^^^1 The 11.25 acre parking lot at the Florida Aquarium in Tampa, FL, was modified
for a study that compared storm water runoff reduction rates from several
different porous pavement applications including swales,asphalt pavement
with swales,asphalt pavement without swales,and cement pavement with swales. Swales, which are areas of vegetation, were
placed between the rows of parking stalls without reducing the total number of stalls. Results showed that for all rainfall events
that produced flow,the basin with pervious paving and a swale reduced runoff by over 60 percent compared to asphalt pavement
with no swale. Also, the area with porous pavement reduced the average amount of runoff by 41 percent compared to the other
areas with swales and impervious pavement. Porous pavement was found to be more effective for small storms; for rainfall events
less than 0.8 inch, the area with porous pavement and a swale had 80-90 percent less runoff than the asphalt pavement without a
swale.
Contact: Betty Rushton, Southwest Florida Water Management District
KINSTON. NC
Parking Lot Demonstration Project
..
Responsible Agency: NC State University
A porous pavement parking lot was designed as a demonstration project,
I monitoring the amount of storm water runoff controlled by both block pavers
and grass pavers.The parking lot was 9,340 square ft and was considered an ideal candidate because it was not a high traffic area, the
in situ soil had sufficient capacity,and there was no indication of a seasonally high water table within five feet of the surface. Modular
and grass pavers were installed in separate areas of the lot, and runoff volumes were monitored from June 1999 through July 2001.
Monitoring results indicated that runoff from the concrete paver parking lot occurred only 11
out of the 48 wet weather events recorded (less than 25 percent of total storms during study
period). In addition, rational method runoff coefficients for the permeable pavement used in
this study were calculated. Rational method runoff coefficients (0-1.0) are a way of describing
the amount of runoff generated during a wet weather event; a coefficient of 0 reflects
maximum rainfall infiltration,whereas a coefficient of 1.0 reflects maximum runoff generation.
The estimated runoff coefficient for the permeable pavement in this study ranged from 0.1-
0.48, depending on method used and amount of precipitation recorded.The project cost was
estimated to be 25 percent more than the cost of building a conventional asphalt parking lot.
Photo: North Carolina State University
Contact: Bill Hunt, North Carolina State University
LID-4
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Low Impact Development: Porous Pavement
References
Booth, D. B. and J. Leavitt, 1999. "Field Evaluation
of Permeable Pavement Systems for Improved Storm
Water Management". Journal of the American Planning
Association. 65:314-325.
Booth, D.B. and Ben Brattebo, 2002. "Permeable Parking
Lot Demonstration Project-The Six-Year Follow-Up". Draft
submitted to Water Research.
EPA Office of Water. 2000. Low Impact Development (LID)
A Literature Review. EPA-841-B-00-005.
EPA Office of Water. 1999a. Preliminary Date Summary of
Urban Storm Water Best Management Practices. EPA-821-
R-99-012.
EPA Office of Water. 1999b. Storm Water Technology Fact
Sheet Porous Pavement. EPA 832-F-99-023.
Low Impact Development Center. "Permeable Paver Costs."
Retrieved October 25,2002. http://www.lid-stormwater.net/
permeable_pavers/permpaver_costs.htm
Storm Water Manager's Resource Center (SMRC). "Storm
Water Management Fact Sheet: Porous Pavement." October
25,2002.
http ://www.st ormwatercenter.net
Tool Base Services (TBS). "Permeable Pavements" Retrieved
October 25, 2002.
http://www.toolbase.org/tertiaryT.asp?TrackID=&CategoryI
D=38&DocumentID=2160
Watershed Management Institute (WMI), 1997.
Operation, Maintenance, and Management of Storm Water
Management Systems. Ingleside, MD.
Georgia Storm Water Management Manual
(GSMM)(Volume 2). 2001.
http://www.georgiastormwater.com
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
LID-5
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LOW IMPACT DEVELOPMENT
Green Roofs
Overview
A green roof is a type of low impact development (LID)
control that uses soil and plant growth for the purpose of
rooftop runoff management. The rooftop vegetation and
underlying soil serve to intercept storm water, delay runoff
peaks, and reduce runoff discharge rates and volume. This
can lead to reductions in the volume or occurrence of
CSOs. A green roof is intended to minimize the impact
of development on hydrologic site conditions through
application of innovative building and engineering design.
Green roof technology has been used in Europe for over
25 years and is gaining increased recognition in the United
States. As shown in Figure 1, the series of engineered layers
that make up a green roof, from bottom to top, typically
include (GBS 2002):
• Waterproof membrane to protect the roof deck
• Root barrier to prevent roots from penetrating the
waterproof membrane
• Optional insulation
• Drainage layer to direct excess water from the roof
• Filter fabric to keep fine soil from clogging the layers
below
• Engineered soil substrate or growing medium
• Vegetation
There are two basic types of green roofs: intensive and
extensive (Peck and Kuhn 2002). Factors to consider when
choosing which type of green roof to install include:
location, structural capacity of the building, budget,
material availability, and client and/or tenant needs.
Intensive Green Roofs
Intensive green roofs, more commonly known
as conventional roof gardens, can be landscaped
environments developed for aesthetics and recreational
uses. The landscaped roofs are likely to include garden-
variety and food producing plants requiring high levels
of management, though the degree of maintenance
can be reduced by using tolerant plants that would
deal well with the micro-climate of the particular
roof (Beckman et al 1997). As ten inches or more of
soil depth is necessary for growing larger trees and
shrubs, intensive green roofs can add as much as 80-
150 pounds per square foot of load to the underlying
structure (Sholz-Barth 2002) and often require an
irrigation and drainage system. Food-producing plants
are usually planted in containers rather than directly
onto the rooftop. Intensive roofs are usually installed
on flat roofs.
Extensive Green Roofs
In contrast to intensive green roofs, extensive green
roofs (also called eco-roofs) are primarily utilized for
their environmental benefits (Beckman 1997). This
type of roof is composed of a continuous thin growing
medium which sustains low-maintenance vegetation
tolerant of local climatological conditions. Extensive
roofs require little maintenance after the vegetation
is established, typically within the first year or two
after installation, and irrigation systems are generally
Vegetation
Soil medium
Filter fabric
Drainage system
Insulation
Root barrier
Waterproof
membrane
Roof surface
Figure 1. Typical layers of a green roof.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
unnecessary. Suitable for large roofs, vegetated cover
will extend across the entire roof and should only
be accessed to perform periodic maintenance. The
extensive green roof can be more readily retrofitted
to an existing structure due to smaller loads, typically
ranging between 15-50 pounds per square foot
(Sholz-Barth 2001). In addition, extensive roofs can be
installed on roofs with slopes up to about 25 percent
(MUSS Manual 2001).
Design considerations for waterproofing, drainage,
and soil type are important in any type of green roof.
Common waterproofing options are rubber, modified
bituminous membrane, polyvinyl chloride (PVC),
rubberized asphalt, thermal polyolefins (TPO), and
coal tar pitch (GBS 2002; Miller 2002). The two
most common waterproofing materials are PVC and
modified bituminous membranes (Miller 2002). To
discourage roots from penetrating the waterproofing
in intensive roof systems, a physical or chemical root
barrier is usually installed over the protective layer.
The key to moisture management and drainage is the
use of absorptive growth media (Miller 2002). There
are various drainage materials that can be used for
moisture management including a synthetic sheet such
as polystyrene or a granular drainage media. Depth
of the drainage layer varies, depending on the level of
runoff management desired and roof loading capacity.
A geosynthetic filter mat is usually placed between
the soil and drainage material to prevent the drainage
system from becoming clogged with fine particles
from the soil. Soils used for vegetated roofs are lighter
in weight than typical soil mixes; they are usually 75
percent mineral aggregate and 25 percent organic
material (MUSS Manual 2001).
Key Considerations
Applicability
Green roofs can be incorporated into new building design
or retrofitted to existing buildings. Green roofs can be fitted
to commercial buildings, multi-family homes, industrial
structures, as well as single-family homes and garages.
Depending on whether the system is intensive or extensive,
green roofs can be installed on either flat or sloping roofs.
Newly developed synthetic drainage materials have made
green roofs feasible to install on most conventional flat
roofs. The appropriate choice of vegetation is determined
by substrate type, soil thickness, regional climate, and
expected precipitation. Intensive and extensive green roofs
have been successfully installed in cities with varying
climatic conditions across the United States. Some factors
that must be considered are the load-bearing capacity of the
roof deck, the moisture and root penetration resistance of
the roof membrane, roof slope and shape, hydraulics, and
wind shear. In regions of the country where snow is part
of the expected annual precipitation, the maximum roof
design loads must incorporate expected snow accumulation
and drifting patterns.
Green roofs can be an important tool to reduce storm
water runoff and subsequent CSOs in areas with dense
development. Heavy development in urbanized areas may
preclude the use of other space-intensive storm water
management practices such as storm water management
detention ponds and large infiltration systems. In these
situations, green roofs maybe a cost-effective technique
for reducing storm water volumes. They can also be a
component of an integrated runoff management program
using a combination of low impact development practices.
Advantages
In a green roof system, storm water is released slowly over a
period of several days rather than discharging immediately
into a sewer system (Beckman et al 1997). Studies show
that both extensive and intensive green roofs can absorb
as much as 75 percent of the precipitation during a typical
rainfall event (Sholz-Barth 2001), while runoff from low
volume storms may be eliminated entirely. The choice of
soil substrates and vegetation will determine the storm
water retention capacity of the roof. When fully saturated,
storm water runoff is filtered through the vegetative layer
to a drainage outlet. The following formula estimates the
potential gallons of precipitation captured based on acres
of green roof area and average annual rainfall (City of
Portland 2002):
[ (Acres of Green Roof) x (43,560 footVacre) x (144 inchVfoot)2 /
(231 inch3/gallon) ] x (60 % of Annual Rainfall in Inches)
= Gallons Rainfall Captured
The gallons of runoff potentially captured by green roofs
in various cities can be calculated based on annual rainfall
statistics and assuming 100 acres of vegetated roof cover.
Table 1 shows hypothetical results for green roofs in
Atlanta, GA; Chicago, IL; Philadelphia, PA; and Portland,
OR. These results will vary depending on rainfall patterns
and whether the rainfall was preceded by a dry period,
which affects absorption.
An additional benefit to green roofs is they can filter air-
borne pollutants that are deposited via precipitation on
the roof (i.e., nitrogen and particulate matter). They can
also help counteract the "urban heat island effect," created
when the natural environment is replaced by pavement
LID-8
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Low Impact Development: Green Roofs
and buildings; green roofs provide a cooling effect as
the plants' foliage evaporate moisture via the process of
evapotranspiration. In addition, green roofs can help
Table 1. Hypothetical gallons of storm water captured,
assuming 100-acres of green roof cover.
Avg. Annual
City Rainfall (Inches)
Atlanta, GA
Chicago, IL
Philadelphia, PA
Portland, OR
48
35
45
37
Potential Gallons
Captured (Millions)
78
57
73
60
reduce the roof temperature and insulate the building, as
well as have aesthetic benefits. Vegetated covers can prolong
the life of a roof by providing ultraviolet protection and
reducing impacts resulting from extreme temperature
fluctuations and high winds. The typical life-span of a
green roof is about 40 years, significantly longer than
a conventional roof. When used as accessible park-like
building amenities, roof gardens can provide substantial
aesthetic benefits. Where self-sufficient native vegetation
tolerant of natural elements is used in green roofs, minimal
maintenance is required.
Disadvantages
Potential disadvantages of green roofs include the difficulty
of repairing possible leaks that are buried under the plant
and soil substrate layers; additional structural support load
requirements for substrate and vegetation layers; and cost
considerations due to increased initial capital outlay. Roof
slope can be a limiting factor as horizontal roofs will require
a system that drains excess water from the root zones, while
sloped roofs may need erosion control measures. Also,
maintenance costs may exceed those of a conventional roof.
Buildings that are retrofitted with green roof covers are likely
to incur more costs than a building that incorporates green
roofs in its construction. For example, a building may need
upgraded structural support for the added weight of the
green roof.
Cost
The average cost of a green roof is estimated at S10-S25 per
square foot compared to conventional roofs that cost S3-S20
per square foot (LIDC 2002; City of Portland 2002). Factors
influencing cost include: the size of the installation; design
complexity; local expertise and suppliers; type and depth of
growing medium; selected vegetation and planting methods
(seed, plug, or pot); and irrigation requirements.
Costs associated with intensive vegetated roofs tend to
be higher compared to extensive roofs due to increased
development and maintenance needs including more
water, fertilizer, weeding, and clipping (Beckman et al
1997). Although green roofs may initially cost more than
conventional roofs, the increase in membrane life-span
and the decreased frequency of replacement make the
green roof a cost-effective choice (City of Portland 2002).
Costs of green roof installation may decrease with further
development of the green roof market in the United States.
In Europe, costs are typically one-fourth of those in the
United States due to a more established green roof market.
LID-9
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Implementation Examples
PHILADELPHIA, PA
Green Roof Demonstration Project
Responsible Agency: Fencing Academy of
Philadelphia A green roof demonstration
project was installed at the
Fencing Academy of Philadelphia.
Like many urban areas on the east coast, 90 percent of all rainfall in Philadelphia occurs
during storms with 24-hour volumes of two inches or less.The 3,000 square foot extensive
green roof was installed on the existing roof with the goal of replicating natural processes
in detaining and treating a rainfall volume. The green roof was designed to reduce the
peak runoff rate of a standard two year, 24-hour design storm. The overall depth of the
green roof is three inches, featuring a synthetic
under-drain layer; thin and lightweight growth
Photo: Roofscapes, Inc.
*'
Photo: Roofscapes, Inc.
media; and, vegetation selected for their hardiness and
tolerance of the local climate. Perennial Sedum varieties create a meadow-like setting and
require no irrigation or regular maintenance. The green roof weighs less than five pounds
per square foot when dry, and approximately 17 pounds per square foot when saturated.
The light weight allows installation on the existing conventional roof without the need for
structural adjustments.The saturated infiltration capacity is 3.5 inches per hour. A pilot-scale
test monitoring rainfall and runoff found that the green roof was able to detain 65% of the
rainfall over a nine-month period. Runoff was negligible for storm events with less than 0.6
inch of rainfall. Based on typical costs of green roofs, the cost of the green roof at the Fencing
Academy is estimated at $18,000 or $6/sq.ft.
Contact: Charlie Miller, Roofscapes, Inc.
PORTLAND, OR
Green Roof Demonstration Project
Responsible Agency: City of Portland The Housing Authority of Portland, in cooperation with the City of Portland's
Housing Authority and Portland Bureau Bureau of Environmenta| services (BES), installed an 8,500 square foot
extensive green roof atop the 10-story Hamilton Apartment building. The
type of vegetation used is hardy plants species such as Sedum, native wild
flowers, and grasses. The Hamilton Apartment green roof system covers 60
percent of the total roof surface area and is comprised of two plots: the first is two inches thick and another is four inches thick.
Storm events and runoff volumes are being monitored. During August 2001, a storm event was monitored for 9.5 hours by the
BES. From a total measured rainfall of 1,485 gallons, 890 gallons ran off the two-inch ««^«^^»
plot and only 80 gallons ran off the four-inch plot.These runoff measurements do not
take into consideration runoff generated from the remaining impervious areas of the
roof (areas without green roof cover) that may be flowing into the green roof plots
or directly into the drainage system. The estimated cost for the project was $70,200.
The City of Portland acknowledges green roofs can play an important role in
storm water management and have included them in their "Clean River Incentive
and Discount Program," which is still under development. This program will offer
incentives and discounts to commercial, industrial, institutional, and residential
properties implementing storm water mitigation measures such as green roofs.
Photo: City of Portland Housing Authority
Con tact: Tom Liptan, City of Portland Storm Water Specialist
LID-10
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Low Impact Development: Green Roofs
CHICAGO. IL
City Hall Green Roof
Responsible Agency: City of Chicago
Twelve stories above ground, the demonstration green roof on Chicago's City
Hall covers 20,300 of the 38,800 square foot roof surface area (one square city
block). This roof was retrofitted as part of an urban heat island effect study initiated by EPA (City of
Chicago 2002). The thickness of this green roof ranges from a 2.4 to 3.4-inches deep. Based on the
structural capacity of the roof, it was determined that the roof could support an extensive system
overall with intensive localized systems over the support columns. Given constraints such as snow load,
the structural capacity for the roof was determined at an average of 30 pounds per square foot.The
precipitation storage capacity was an average of one inch of rain. About 20,000 plants were used for the
green roof, including those native to the Chicago region and tolerant of dry soil and sunny conditions.
A drip-irrigation system, partially served by roof runoff collected in storage tanks, was installed as a
supplemental water source for the plants during roof establishment and dry periods. Monitoring plant
survival and environmental benefits related to energy and "urban heat island effect" is in process. Due
to the expense of installing flow meters, storm water runoff is not being monitored at this site.The
vegetated cover cost was $500,000 of the entire re-roofing project cost, which totaled $1.5 million.
Photo: City of Chicago
Contact: Mark Farina, City of Chicago
References
Beckman, S.; Jones, S.; Liburdy, K.; and Peters, C., Greening
Our Cities: An Analysis of the Benefits and Barriers
Associated with Green Roofs. Planning Workshop at Portland
State University, 1997.
http://www.greenroofs.com/Ecotrust%20Article.pdfhttp:
//www.lsdg.net/EcoRoofs.pdf
City of Chicago. "The components and design report of
City Hall's Rooftop Garden." Retrieved December 2002.
http://www.ci.chi.il.us/Environment/rooftopgarden/
designpage.html
City of Portland. "Ecoroof: Question and Answers"
Retrieved December 2002.
http://www.cleanrivers-pdx.org/pdf/eco_questions.pdf
Green Building Services (GBS). "Green Rooftop
Technology." Retrieved November 2002.
http://www.greenbuildingservices.com/green_resources/
pdfs/ecoroofs.pdf
Low Impact Development Center (LIDC). "General
Information on Green Roofs." Retrieved November 2002.
http://www.lid-stormwater.net/intro/
sitemap.htm#greenroofs
Miller, Charlie. Interviewed by Limno-Tech, Inc. 2002.
Minnesota Urban Small Sites (MUSS). 2001. BMP Manual:
Storm Water Best Management Practices for Cold Climates.
Prepared for the Metropolitan Council Environmental
Services by Barr Engineering Company.
Peck, Steven and Monica Kuhn. "Design Guidelines for
Green Roofs." Retrieved October 18, 2002.
http://www.cmhc-schl.gc.ca/en/imquaf/
himu/loader.cfm?url=/commonspot/security/
getfile.cfm&PageID=32570
Sholz-Barth, Katrin. 2001. "Green Roofs: Stormwater
Management from the Top Down." Environmental Design &
Construction Magazine. Jan-Feb. 2001:1-11.
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
LID-11
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TECHNOLOGY
RIPTION
LOW IMPACT DEVELOPMENT
Bioretention
Overview
Bioretention is a soil and plant-based storm water
management practice used to filter and infiltrate runoff
from impervious areas such as streets, parking lots, and
rooftops. Essentially, bioretention systems are engineered
plant-based filters designed to mimic the infiltrative
properties of naturally vegetated areas, which in turn can
reduce the volume and frequency of CSOs. Bioretention is
considered a low impact development (LID) practice and
was developed in the early 1990s.
One of the unique qualities of bioretention is the flexibility
of design themes. Bioretention systems can range in
complexity depending on available funding, volume of
runoff to be controlled, available land area, and the desired
level of treatment. Bioretention systems can be used as a
stand-alone practice (off-line) or connected to a storm
drainage system (on-line). It is important to note that
changes and improvements to a bioretention system design
are continually being made as use of the practice becomes
more developed.
On-line Bioretention System
A typical on-line bioretention system, as shown in
Figure 1, includes components designed to capture,
temporarily store, infiltrate, and treat storm water
runoff. A graded surface conveys the runoff from
impervious areas (i.e. roofs, driveways, parking lots)
toward an optional grass buffer or swale. The grass
buffer pretreats the runoff by reducing the runoff
velocity, filtering particulates, and evenly distributing
the incoming runoff. The rain garden, the main
treatment component of an on-line bioretention
system, is located in a depressed area that allows the
runoff to pond and infiltrate, as well as evaporate from
the surface. The rain garden is usually designed to
hold up to six inches of standing water for one or two
days, and consists of a mix of woody and herbaceous
species planted in a soil mixture designed to optimize
percolation and pollutant removal. The best type of
vegetation is native plant species that are tolerant of
both wet and dry conditions. The planting soil should
be two to four feet deep topped with an organic layer.
This configuration allows the rain garden to maximize
biological activity and enhance root growth. Factors
affecting depth of the system include size of plants
and depth to groundwater. Under the planting soil
layer is a gravel layer that blankets an underdrain and
serves to increase porosity of the system (Figure 1).
The underdrain, a perforated pipe that collects and
carries the runoff to the storm water system, ensures
proper drainage for the plants and proper infiltration
rates. Earlier bioretention system designs included a
filter fabric between the soil and gravel layers, however
this was found to cause premature clogging that led to
infiltration problems. Replacing the filter fabric with
a pea gravel diaphragm is an option. For storm flows
exceeding the system's storage capacity, the excess
Runoff
Pavement
Gravel
Blanket
Underdrain
Berm
Ponding Zone
(0.51)
Filtration Zone
Recharge Zone
(V)
Adapted from PGC 2002
Figure 1. Cross-section of an on-line bioretention system.
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Report to Congress on the Impacts and Control ofCSOs and SSOs
runoff is allowed to flow over a grassy berm swale into
an inlet pipe connected to the storm drain system.
Other system designs allow the treated storm water to
percolate back into the groundwater.
Off-line Bioretention Systems
Off-line bioretention systems possess similar general
features to on-line systems, but are more simplistic
and tend to be smaller in scale. One common design is
where the bioretention areas (i.e. flower beds or other
landscaping) are depressed so ponding and infiltration
of storm water runoff can occur. Such designs do not
include underdrains. Excess runoff overflows onto the
adjacent surface areas. Another design is a bioretention
"trap area" used in tree box areas, behind curbing,
sidewalks, and pathways. With this technique, the paved
surface is graded toward the adjoining grass areas to
intercept runoff as it flows towards a drain or gutter
(PGC 2002). Bioretention trap areas are common in
urban areas with limited open space and high flow
rates. In turn, tree boxes can be designed to serve as
localized bioretention systems. This is done by creating
a shallow ponding storage area by "dishing" mulch
around the base of the tree or shrub (Figure 2).
Grassy or Paved Area
Adapted from PGC 2002
Figure 2. Schematic diagram of a tree-pit, which is a type of
off-line bioretention system
Successful bioretention systems may also include soil
amendments, which aim to improve health of the soil
and its environmental functions. As a result of urban
development, soils become compacted, which reduces
soil porosity and ability to absorb water (ODEQ 2001).
One type of soil amendment that can improve runoff
absorption and treatment is the addition of compost.
According to the Natural Resources Conservation
Services (NRCS) hydrologic soils classification,
compacted urban soils are classified under Group D
due to their limited ability to infiltrate runoff. Compost
amendments can upgrade the compacted urban soils
to Group B, soil with moderate infiltration rates, by
increasing soil porosity (AACED 2002; City of Portland
2002). The soil is amended by spreading a layer of
compost on the surface and tilling both the soil and
compost to a total depth of 12 inches. The general soil
to compost ratio rule is 2:1 by unit volume (ODEQ
2001).
Key Considerations
Applicability
Both on-line and off-line bioretention can be utilized in
new developments or be retrofitted into developed areas.
However, there is much more latitude to incorporate
bioretention practices in new developments because there
are fewer constraints regarding siting and sizing. In fact,
good planning and design may result in an integrated site-
wide bioretention system that decreases both initial project
costs and long-term maintenance expenses. Bioretention
practices are applicable in heavily urbanized areas such
as commercial, residential, and industrial developments.
For example, bioretention can be used as a storm water
management technique in median strips, parking lots
with or without curbs, traffic islands, sidewalks, and other
impervious areas (EPA 1999).
The effectiveness of a bioretention system is a function of
its infiltration and treatment ability and so the system must
be sized to match the expected runoff. Miscalculating the
capacity limits in the system design can lead to erosion and
stabilization issues, particularly for on-line systems. The
following criteria can be used to determine the suitability of
bioretention:
• Drainage area - 0.25 to one acre per bioretention
system (multiple systems maybe required for larger
areas);
• Space required - Approximately five percent of the
impervious area that will contribute runoff; and
• Minimum depth to water table - No less than two feet
between ground surface and seasonally high water
table.
Typical maintenance activities for any bioretention system
are re-mulching void areas; treating, removing, and
replacing dead or diseased vegetation; watering plants until
they are established; soil inspection and repair; and litter
and debris removal.
LID-14
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Low Impact Development Technology: Bioretention
Advantages
Bioretention reduces storm water runoff and can
consequently help reduce the size and cost of storm water
control facilities, and the volume and frequency of CSOs.
Bioretention can be an effective LID retrofit, especially
in urban areas with minimal open space and extensive
impervious area. Bioretention systems have also shown
promise in the removal of pollutants via physical and
biological processes of adsorption, filtration, plant uptake,
microbial activity, decomposition, sedimentation, and
volatilization (EPA 1999). Types of pollutants removed
include metals, phosphorus, hydrocarbons, suspended
solids, nitrogen, organic matter, and oils (EPA 1999). Also,
bioretention systems can reduce on-site flooding, improve
groundwater recharge, help maintain stream baseflows,
provide habitat, and have aesthetic value. On-line systems
are most cost-effective when incorporated into the initial
design or into the repair/reconstruction process of an area
(i.e. parking lots). Off-line bioretention systems are cost-
effective as retrofits in urban areas as they require little space
and can be incorporated into existing urban landscapes.
Disadvantages
Functional problems of bioretention systems may arise
such as clogging of the ponding area with sediment over
time. Thus, pretreatment and regular maintenance are
necessary components to the overall implementation. In
many cases, maintenance tasks can be completed by a
landscaping contractor. Systems with compost amendments
require regular replacement of the compost. Additional soil
amendments, such as lime or gypsum, may also be necessary
to replenish nutritional deficiencies and correct unsuitable
alkalinity levels (Chollak and Rosenfeld 1998).
Cost
The cost of a residential off-line bioretention system
averages about S3-S4 per square foot, depending on the
soil conditions and the density and types of plants used,
whereas the cost of commercial, industrial, and institutional
applications of bioretention systems range between S10-S40
per square foot, based on the need for control structures,
curbing, storm drains, and underdrains (LID 2003).
Landscaping costs required regardless of bioretention
installation should be subtracted when determining the net
cost of the bioretention system. As the size of bioretention
systems can vary, so can the associated installation costs.
In addition, in residential areas, storm water management
controls become a part of each property owner's landscape,
reducing the public burden to maintain large centralized
facilities (LID 2003).
Retrofitting a site may entail additional costs (EPA 1999).
The higher cost of a retrofit is attributed to the demolition
of existing concrete, asphalt, and other structures and
replacing fill material with planting soil. The costs of soil
amendments are site specific as well. For a shallow (up to an
8-inch depth) compost amendment that incorporates in-site
soil in a small area, the estimated cost is S1-S3 per square
foot (LID 2002).
Bioretention has the potential for cost savings compared
to other types of storm water drainage techniques, such
as curbs and gutters. The operation and maintenance
costs for a bioretention facility are comparable to that of
typical landscaping. Additional costs beyond the normal
landscaping fees will be site specific, but can include soil
testing, planting soil installation, and soil amendment
components.
LID-15
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Implementation Examples
MAPLEWOOD, MN
Rain Gardens in Residential Development
Responsible Agency: City of Maplewood _, _.. ...
TheCityofMaplewood launched a storm water management project that
implemented rain gardens instead of traditional curband guttersystems
in three neighborhoods.This decision was prompted by a combination of positive results of previously completed rain garden pilot
projects, the need for road upgrades, and existing drainage problems in several neighborhoods. Considering bioretention as an
environmentally friendly and aesthetically pleasing alternative,the city decided to focus on demonstration,education,and outreach
to convey the benefits of using rain gardens for runoff management. Each bioretention system incorporated rain gardens and grass
swales to collect runoff from streets and yards with a holding capacity of 0.5 inch of rain (85 percent of the local rainfall occurs during
storms totaling 0.5 inch or less) (NSN 2001).The utilization of rain gardens in the neighborhoods was on a voluntary basis. However,
the city offered incentives providing homeowners with plants, landscape plans, educational materials, and demonstrations free of
charge.The three standard garden sizes offered were 12 foot by 24 foot, 10 foot by 20 foot,and 8 foot by 16 foot. At least 130 rain
gardens are expected to be installed by the end of 2003. Within the project neighborhoods, the city is installing rain garden systems
at schools, nature centers, and neighborhood parks.The city is providing necessary regrading or curb work to achieve the proper
slope for each system.Volunteers for disabled or elderly residents wishing to participate in the program are being provided as well.
Whether the residents utilize the gardens or not, all residents must pay an annual assessment to cover the costs of the projects.
This bioretention project costs 75-85 percent of the cost of traditional curband gutter systems (NSN 2001). Each garden costs $600-
$700 including excavation, rock infiltration sump, scarifying of the soils, bedding material, shredded wood mulch, and vegetation.
Costs were kept low by recycling and using street material in lieu of gravel, by obtaining the plants from a local correctional facility
green house program,and by having residents be responsible for the planting. Otherwise, the cost of each garden was estimated to
be between $1,200-$1,500.The potential long-term savings are more difficult to quantify, but include reduced demand on the city's
downstream storm sewer infrastructure.
. ,
. .§fc1*
Photo: City of Ma plewood
Contact: Chris Cavett, Assistant City Engineer, City of Maplewood
LID-16
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Low Impact Development Technology: Bioretention
PRINCE GEORGE'S
COUNTY, MD
Residential Rain Garden Program
Responsible Agency: Prince George's
Department of Environmental Resources An 8°-acre resldentlal development site in Prince Georges County,
MD, consisting of 199 homes on 10,000 square foot lots was designed
featuring bioretention rain gardens. One to two rain gardens were built
on each lot in the development. Each garden is 300-400 square feet in size and consists of ornamental grasses, mulch, shrubs, and
trees. The rain gardens were implemented as means of storm water attenuation. The gardens control storm water quantity and
quality by collecting runoff from driveways and rooftops for infiltration into the ground. Each garden generally includes a mulch layer
underlain by a sandy loam or loamy sand planting media with a minimum depth of two feet. A one-foot sand layer was placed below
the planting media to help store the runoff at sites with low porosity subsurface soils. Grassy swales were used to connect the rain
gardens to storm drain inlets and provided additional quantity and quality management compared to a traditional curb and gutter
system. Water was allowed to pool to a depth of six inches in the rain garden after each rain event.The basins provided a maximum
of 48-hour storage onsite.
Analysis of the project costs showed the rain gardens were a cost-effective storm water management strategy. Each garden cost
approximately $500, which consisted of $150 for excavation and $350 for vegetation. The total cost of the project was $100,000
compared to the projected cost of $400,000 for a pond system which was the other storm water management alternative considered
for the development. In addition, this allowed the developer to recover six lots that otherwise would have been used for the pond
system. The area's naturally sandy soil was suitable for the sand base required in the rain garden profile, which kept the costs of
the gardens down. Homeowners are responsible for replacing dead vegetation, regulating soil pH, removing filter clogs and excess
sedimentation, keeping the storm water intake open, and repairing erosion damage.The overall savings to the developer from the
use of bioretention was over $4,000 per lot.
Photo: Prince George's County DER
Photo: Prince George's County DER
Contact: Larry Coffman, Prince George's County Department of Environmental Resources
LID-17
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Report to Congress on the Impacts and Control ofCSOs and SSOs
WASHINGTON, DC
Bioretention System Retrofits
Responsible Agency: U.S. Navy
The Navy demonstrated LID effectiveness and applicability by installing
a number of storm water retrofits, including both on-line and off-line
bioretention systems, throughout the Washington Navy Yard (Lehnerefa/. 1999).These retrofits complement the Navy's effort to
update the 150-year old separate storm sewer system. Video investigation, cleaning, and system modernization were conducted
prior to the installation of ten pilot projects demonstrating the use of LID techniques in urban areas. Currently, the projects are
undergoing monitoring and evaluation of maintenance requirements and pollution control effectiveness. Engineers designed the
bioretention retrofits to treat the first one-half inch of rain, at a minimum.The two main retrofits were at the Willard Park and Dental
Clinic parking lots, and cover a total of three acres of impervious surface. The Willard Park parking area incorporated the on-line
bioretention retrofits in the replacement and repair of the parking lot. Bioretention was utilized to temporarily store and slowly
release storm water to reduce the peak discharge. In an effort to maximize parking area, the bioretention systems were installed as
strips between parking rows. Each unit is designed to treat 0.5 acre of impervious surface.
The Dental Clinic project is an example of implementing a combination of LID practices as part of a major reconstruction of the
parking lot. Bioretention islands, sand filter gutter strips,and permeable pavers were installed between parking rows. Also,a tree box
was installed within the property and soil amendments were made in some open space areas to increase infiltration capabilities of
the soil.
Contact: Camille Destafney, Naval District Washington
References
Anne Arundel County Environmental Demonstration
(AACED). "Revitalizing Compacted Soils." Retrieved
November 11,2002.
http://www.srlt.org/compactsoils.shtml
Chollak, Tracy and Paul Rosenfeld. 1998. Guidelines for
Landscaping with Compost-Amended Soils. Prepared for City
of Redmond Public Works.
City of Portland. 2002. Storm Water Management Manual.
Environmental Services City of Portland Clean Water
Works. Portland: City of Portland.
Coffman, Larry. Interview by Limno-Tech, Inc., 2002.
EPA. 1999. Storm Water Technology Fact Sheet: Bioretention.
EPA832-F-99-012.
Lehner, Peter, George Aponte Clark, Diane Cameron,
Andrew Frank. 1999. Storm water Strategies: Community
Responses to Runoff Pollution. New York: Natural Resources
Defense Council.
Low Impact Development Center (LID) "Bioretention Cell
Costs" Retrieved April 30,2003.
http://www.lid-stormwater.net/bioretention/bio_costs.htm
Low Impact Development Center (LID) "Soil Amendment
Costs." Retrieved November 21,2002.
http://www.lid-stormwater.net/soilamend/soilamend_
costs.htm
Nonpoint Source News-Notes. "Landscaped Rain Gardens
Offer Stormwater Control." In Notes on Watershed
Management. No. 66. October 2001. Retrieved November
14,2002.
http://notes.tetratech-ffx.com/newsnotes.nsf
Oregon Department of Environmental Quality (ODEQ).
2001. Restoring Soil Health To Urbanized Lands: The Crucial
Link between Waste Prevention, Land Use, Construction,
Stormwater Management and Salmon Habitat Restoration.
Portland: Oregon Department of Environmental Quality.
Prince George's County Department of Environmental
Resource, Programs and Planning Division (PGC) 2002.
The Bioretention Manual. Prince George's County, MD:
Department of Environmental Resource, Programs and
Planning Division.
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
LID-18
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LOW IMPACT DEVELOPMENT
Water Conservation
Overview
Water conservation is the careful and efficient use of
water in a manner that extends water supplies, conserves
energy, and reduces water and wastewater treatment costs.
As such, it is considered to be a low impact development
(LID) control. With regard to CSO and SSO control, the
reduced use of water through water conservation can
decrease the total volume of dry weather sanitary sewage
flowing through a sewer collection system. This produces
an increase in conveyance and treatment capacity which
then prevents some sewage from being discharged during
periods when runoff, infiltration, and blockage exacerbate
capacity constraints within wastewater collection systems.
Water conservation can be an important component of
a program to control sewer overflows. It is not often a
solution on its own, but can be effective when implemented
in combination with other control methods.
There is a broad group of indoor and outdoor practices
that reduces water consumption. Several of the important
water conservation practices to reduce CSOs and SSOs are
described below.
Water Efficient Fixtures and Appliances
Low-flow fixtures include low-flow toilets and urinals,
showerheads, and faucets. Aerators, which break the
flowing water into fine droplets by incorporating air
without affecting wetting effectiveness, can be attached
to showerheads and faucets to reduce water use. Self-
closing and sensored faucets with automated water flow
are available for commercial facilities (PNNL 2001).
Installation of pressure-reducing valves can lower water
consumption by reducing water flow and the likelihood
of leaking pipes and faucets. Water efficient clothes
and dish washers are also available. For example, high
performance clothes washers can reduce water use from
35-55 to 18-25 gallons per load (PNNL 2001).
Water Recycling
Water recycling is the reuse of water for beneficial
purposes (EPA 1998). Greywater, which is wastewater
from sinks, kitchens, tubs, clothes and dish washers,
can be reused for home gardening, lawn maintenance,
cooling tower or boiler makeup water, landscaping,
toilets, and exterior washing. More elaborate treated
effluent recycling measures can also be implemented
for residential, agricultural, and industrial uses.
Waterless Technology
Some available technologies eliminate the need for
water for operation. Composting toilets treat domestic
sewage (also food scraps, paper, lawn clippings,
and grease) by composting and dehydration. This
technology does not require hook-up to sewage or
septic systems, and the end-product can be used as
fertilizer. Waterless urinals use a liquid with a lower
specific gravity than urine, such as barrier oil or other
sealant liquid, that allows waste to pass through while
an airlock cartridge in the base of the urine bowl
prevents any malodor (GBS 2002).
Rain Harvesting
Rain harvesting is an interception practice that collects
and stores roof runoff before it enters the sewer or
storm water system. Typical components of a rain
collecting system are a gutter or down spout; holding
vessels (i.e., cisterns, rain barrels, or tanks); and a filter
or screen (TWDB et al. 1997). Most often, harvested
water is for home gardening or lawn care. More
complex systems designed to collect water for in-home
use require a water treatment system to settle, filter, and
disinfect the water, as well as a gravity or pump system
to transport the treated water (TWDB et al. 1997).
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Key Considerations
Applicability
Water conservation makes sense for many reasons.
One important reason is the contribution that water
conservation can make to reducing the volume of CSO and
SSO discharges. A few considerations regarding specific
practices are discussed in the paragraphs below.
Water Efficient Fixtures and Appliances
Water efficient fixtures can be installed or retrofitted in
residential, commercial, institutional, and recreational
facilities. Buildings undergoing construction or
remodeling have great potential for incorporating
water-wise technologies, and most of these technologies
are readily available in the U.S. Water efficient fixtures
can be a practical and economical alternative for
homes.
Toilets, showers, and faucets account for approximately
60% of all indoor residential water use (EPA 1995).
In most instances, money saved from reduced water
and sewer bills can offset installation costs over time,
and the reduction of wastewater places less stress on
sewer systems. Toilets in particular are one of the
greatest residential water uses and have considerable
water saving potential. By installing low-flow toilets,
toilet water use can be reduced from more than 3.5
gallons to 1.6 or less gallons per flush (gpf). Low-flow
toilets function similar to conventional toilets, and
are therefore easy to substitute. Since low-flow toilets
were first introduced in the 1980s, manufacturers
have made significant improvements in toilet design,
thus reducing the need to double flush, which was a
source of customer dissatisfaction and a reduction
in efficiency among earlier models (EPA 2002). In
fact, current federal law requires that residential
toilets manufactured after January 1,1994, must use
no more than 1.6 gpf; and that commercial toilets
manufactured after January 1, 1997, must use no more
than 1.6 gpf; and urinals must use no more than 1 gpf
(FEMP 2002). Similar to low-flow toilets, low-flow
showerheads conserve water by reducing water use
from 4.5 to 2.5 gallons per minute (gpm) (EPA 1995).
These showerheads are simple to install and relatively
inexpensive, but flow can be reduced over time by scale
buildup (EPA 1995). Various cities throughout the U.S.
have established incentive programs, such as rebates,
promoting the use of low-flow or water efficient
technologies.
Water Recycling and Reuse
Water recycling and reuse have the potential to satisfy
many household water needs and have numerous
potential applications. In general, water recycling
provides a locally controlled water supply that can
be developed in both residential and non-residential
facilities. Benefits to users of greywater systems
are reduced water and sewer bills due to lowered
wastewater discharge and water usage. Reuse of
greywater also can improve local water quality by
reducing greywater pollution (i.e. organics) that may
otherwise be discharged into local rivers and streams
during sewer overflow events. The disadvantages
are mainly in the costs of equipment and labor to
install the system. For more complex systems, the
economic payback period may extend beyond the life
of the system. Periodic maintenance is required, and
contaminants such as paint, bleach, and dye must
not enter the system. Some local regulations may
not be adapted for such systems. Sanitary engineers,
inspectors, and boards of health may lack familiarity
with such systems as well.
Cooling tower water recycling is most useful for
commercial, institutional, and industrial facilities such
as hospitals, factories, nuclear power plants, apartment
buildings, and chemical plants. The recycling of cooling
water reduces wastewater discharge, lowers water and
sewer bills, and reduces the discharge of chemicals
to wastewater collection systems. The operation of
recirculating cooling towers in industrial buildings,
however, can reduce production efficiency as the
system pumps consume power. Regular maintenance is
required to ensure efficient application of cooling tower
technologies.
Waterless Technology
Technologies that eliminate the need for water all
together are the ultimate water conservation tool.
Composting toilets are particularly suitable for use
in recreational facilities such as parks, although there
are residential and commercial applications as well.
The advantages include eliminating the need for
potable water to flush the toilet and reduced sewer
bills. Composting toilets, however, are not ideal in cold
climates, can require some energy (i.e., ventilation and
heating) to optimize composting, and need regular
maintenance. Waterless urinals are another product line
that conserve water. While suitable for commercial and
other public facilities, their use can be limited because
they are not always socially acceptable, and they require
regular maintenance.
Institutions such as hospitals can benefit from ozonated
laundering which provides disinfection but does
not require detergent or rinsing. Ozone generation
is power-intensive, requiring significant amounts
LID-20
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Low Impact Development: Water Conservation
of electricity that may reduce its cost-effectiveness
in certain applications. Also, ozone is reactive and
corrosive and thus requires resistant material such as
stainless steel (NSFC 1998).
Rain Harvesting
Important considerations for rain harvesting include
age and type of roof, amount of canopy overhang, and
availability of space to position rain barrels or other
storage units. Rain harvesting costs vary depending on
the complexity of the system. Rainwater yield varies with
the size and texture of the catchment area. Systems can
be custom designed and built or purchased as a package.
Minimal costs are associated with simple systems
consisting of a gutter and collection barrel serving a
home. Applications of rain harvesting can be limited to
certain geographical regions, as some western states have
water laws that may impose restrictions on the practice
of rain harvesting.
Cost
Important considerations in evaluating the effectiveness
of water conservation technologies include determining
if the water conservation savings offset the costs of
implementing the technology; assessing the feasibility of
the technology given local restrictions and building codes;
size and complexity of installation; location (residential
vs. non-residential); and local water and sewer rates. Cost-
effectiveness of specific technologies varies greatly depending
on water use and geography. It is also important to consider
the water conservation potential of combining the various
technologies.
Among water efficient fixtures and appliances, low-flow
showerheads and faucet aerators are almost always cost-
effective due to the relative low cost and minimal labor
required. Low-flow toilets also have widespread application,
particularly in commercial and institutional settings,
because the economic offset period can be relatively short.
The cost-effectiveness of other technologies mentioned
in this fact sheet, however, will be based on site-specific
considerations. Major factors affecting the cost-effectiveness
of water efficient landscaping include landscape area, type of
vegetation, geography, and climate. The cost-effectiveness of
rain harvesting is controlled by the amount of rainfall and
storage capacity. For greywater systems, the cost-effectiveness
will vary based on flow rate, water quality, temperature,
local building regulations (TBS 2002), and size of the
reuse system. Due to the various types of applications for
cooling towers, cost-effectiveness calculations are system
specific. The cost-effectiveness of waterless technology will
be controlled by the availability of connections to water and
sewer lines. Table 1 provides general estimates of the costs
and benefits of each water conservation technology.
Table 1. Water conservation technology cost and performance .
Category
Water Efficient
Fixtures and
Appliances
Recycling/
Reuse
Waterless
Rain Harvesting
Technology
Ultra low-flow toilet
Low-flow showerhead
Faucet aerator
Clothes washer
Residential greywater
reuse
Cooling tower
Composting toilet
Waterless urinal
Rain barrels or cisterns
% Water
Conserved2
54-68%
45%
40%
49-55%
up to 54%
up to 90%
1 00%
1 00%
Varies
Approximate
Cost ($)
$200-300
$23
$13
$1000
$400-$5000
Not Available
$1000-$2000
$300-$500
$100-$20,000
Life Span
(yrs.)
15-25
2-10
1-3
12
Not Available
Not Available
Not Available
Not Available
Not Available
'These estimates are for illustrative purposes and may not be applicable to a given situation. Estimates are from
various sources including PNNL 2001 and CUWCC 2002.
2 Percentage of water saved when compared to conventional water use application (no conservation measures
taken).
LID-21
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Report to Congress on the Impacts and Control ofCSOs and SSOs
Implementation Examples
SIERRA VISTA, AZ "Water Watch" Program
Responsible Agency: Sierra Vista Water
Management Team The City of Sierra Vista established a water management team in September
2000 to assess the public's perception of local water issues, educate and
involve the public on water management issues, provide incentive-based
conservation alternatives,identify and address new water conservation opportunities,and implement water conservation programs.
The water conservation programs include a toilet rebate program to encourage residents to voluntarily install low-flow toilets, free
in-home retrofits of high-use water fixtures, a leak detection prog ram,an internal "Water Watch" program to monitor municipal water
use, public education and surveying,and partnerships with the Chamber of Commerce to involve the business community. For the
toilet rebate program, qualified participants received $100 for each unit replaced with a limit of two units per household. Sierra
Vista has approximately 13,400 homes built prior to 1987 that may have high-flow toilets and fixtures. Replacement of all high-flow
fixtures could save the city up to 261 million gallons of water annually.The old high-flow fixtures collected by the city through this
rebate program were crushed and used as road-base material for various city projects. For fiscal year 2002,195 toilets were replaced
through the rebate program saving two million gallons of water, while 110 homes were retrofitted with low-flow fixtures saving an
additional 3.3 million gallons of water. The program provided homeowners the opportunity to have their high-flow fixtures modified
with low-flow alternatives at no cost to the homeowner. Sierra Vista has also taken regulatory measures by adding the following code
requirements:
New commercial car washes must recycle 75% of their water
Waterless urinals in all commercial facilities with urinals
Turf limits for new golf courses and new developments
Commercial landscapes must feature low water use plants from city-approved list
New irrigation standards for steep slopes and medians
Hot water recirculating pumps in new homes
Independent water meters required for each multi-family unit
In addition, the "Water Watch" program involved internal monitoring and evaluation aimed at reducing water consumption in the
city's facilities. Monthly water invoices from the city's use of water from its wells and from private water companies were checked for
anomalies.Trained personnel also conducted inspections at virtually all of the city's facilities, providing an inventory of waterfixtures
and identifying leaks and inefficiencies.The city was also involved in an internal retrofitting program where water fixtures were
replaced with low-flow units. A study by the city showed the total acre-feet of water consumed between calendar year 2000 to 2001
decreased from 2.5 billion gallons to 2.3 billion gallons of water for Sierra Vista.
Contact: Patrick J. Bell, Environmental Services Manager, City of Sierra Vista
ALBUQUERQUE. NM Water Recycling in Cooling System
Responsible Agency: U.S. Department of Energy
Sandia National Laboratory has established several water
conservation programs within its facilities, one of which is located
at the Compound Semiconductor Research Laboratory (CSRL). The CSRL replaced its cooling system used for its laser installations
from a once-through water cooling system to a cooling loop cooling system. By reusing cooling water, CSRL is able to save five to
ten million gallons of water peryear based on normal usage. The water bill savings are estimated at $10,000-$30,000 peryear.The
project cost was $200,000.
Contact: Darrell Rogers, Sandia National Laboratories
LID-22
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Low Impact Development: Water Conservation
HOUSTON, TX
Water Efficient Fixtures In Housing Project
Responsible Agency: City of Houston and
Houston Housing Authority Joint Water
Conservation Project
Low-flow plumbing fixtures were installed in a 60-unit low income multifamily
housing complex in Houston, owned and managed by the Housing Authority of
the City of Houston (HACH).The average number of occupants per unit was 4.4.
Devices installed in each unitincluded low-flowtoilets(1.6gpf),low-flowaerators
on faucets (2.2 gpm),and new water meters for each unit. Faucet leaks were repaired,and tenants were educated on conservation
techniques. The project resulted in a reduction in average monthly water consumption for the complex from 1.3 million gallons
pre-installation to 367,000 gallons post-installation. Average monthly savings on water bills for the complex was $6,834. Due to the
success of the project, HACH (funded by HUD) has retrofitted four of its other low income housing developments.
Water use and bill comparison before and after project.
Water Use Comparison
Avg Monthly Consumption
Avg Monthly Consumption/Unit
Avg Monthly Consumption/Person
Avg Consumption/Person/Day
Water Bill Comparison
Avg Monthly Bill
Avg Monthly Bill/Unit
Before
1,300,000 gals.
21, 666 gals.
4,924 gals.
146 gals.
$8,644.00
$144.00
After
376,000 gals.
6,1 16 gals.
1,390 gals.
46 gals.
$1,810.00
$30.17
Contact: PatTruesdale, City of Houston Public Works and
Engineers Water Conservation Branch
HILLSBOROUGH
COUNTY. FL
H
Water Conservation Program
Responsible Agency: Hillsborough County
Water Department
Due to rapid urban growth on Florida's west coast, Hillsborough County's
water resources were experiencing significant stress. To address this
problem, the county established a comprehensive water conservation
program. The program is composed of public education and regulatory, operational, and financial incentive/disincentive
components. Examples of some of the program's projects include full-time enforcement of water use restrictions, rebates for water
efficient devices, and educating communities on water conservation. The program has effectively reduced the per capita water
consumption in the county from 146 to 105 gallons per person per day; well below the regional requirement of 130 gallons.The
low-flow toilet rebate program that was started in 1994 replaced 75,200 fixtures, saving an estimated 1.7 MGD. The county also
established a reclaimed water program where approximately 11 million gallons of reclaimed water are used by approximately
7,000 residential and commercial customers daily, and the numbers are growing.This program has helped reduce the need for
groundwater withdrawals and wastewater discharges.
Contact: Norman Harcourt Davis IV, Water Conservation Manager,
Hillsborough County Water Department
LID-23
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Report to Congress on the Impacts and Control ofCSOs and SSOs
WASHINGTON. DC
Rain Harvesting Study
Responsible Agency: DC Water and Sewer
Authority (WASA) In 2001, the DC Water and
Sewer Authority undertook a
study of the effectiveness of
rain harvesting in controlling storm water runoff from rooftops within its combined sewer
service area. Rooftops are a major type of impervious surface whose runoff can contribute
to CSO events. Rain barrels were analyzed as a means for capturing storm water runoff
from rooftops, thereby reducing flow in the combined sewer system. The 75-gallon rain
barrels were installed at two types of homes (detached and rowhouse), each with distinct
roof configurations, and were monitored over a nine-month period. For the study area,
under a design rainfall of 0.19 inch, the study showed that approximately 27,521 gallons
out of a total of 211,950 gallons of runoff generated would be controlled using rain barrels.
Rain harvesting from roofs on rowhouses appeared to be more cost-effective than on
detached homes. Calculations indicated that for a one million gallon reduction in storm
water volume, rain barrels would need to be installed in 20 percent of the rowhouses at an
estimated cost of $1.7 million (MWCOG 2001).
Photo: DC WASA
Contact: Phong Trieu, Peter Guillozet, John Galli, or Matt Smith,
Metropolitan Washington Council of Governments
COLORADO SPRINGS. CO
Water Reuse at Vehicle Wash
Responsible Agency: U.S.Army
Fort Carson's Central Vehicle Wash Facility services
approximately 4,000 military vehicles using recycled
water and has been in operation for over 11 years. This facility is an example of
a closed loop recycling water treatment system that consists of grit chambers,
sand filters, oil skimmers, and aeration basins,and has a storage capacity of 9.6
million gallons. Grass carp were introduced in the aeration and stilling basins to
control aquatic vegetation and to avoid use of algacides. On a given day, up to
491 vehicles can be washed, using 10 million gallons of water. As this treatment
system is essentially self-sustaining, there is minimal impact on Fort Carson's
sewage and industrial wastewater treatment systems.The yearly rainfall is usually
sufficient to make-up for evaporation losses. Each year, the system conserves
150-200 million gallons of water. The facility was built at a cost of $7 million.
Contact:Richard Pilatzke, Fort Carson
LID-24
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Low Impact Development: Water Conservation
References
California Urban Water Conservation Council. "H2Ouse."
Retrieved October 16,2002.
http://www.h2ouse.net/action/index.cfm
EPA Office of Water. "High Efficiency Toilets." Retrieved
June 28, 2002.
http://www.epa.gov/OW-OWM.html/water-efficiency/
toilets.htm
EPA Water Division Region 9.1998. Water Recycling and
Reuse: The Environmental Benefits. EPA 909-F-98-001.
EPA Office of Water. 1995. Cleaner Water Through
Conservation. EPA 841-B-95-002.
Federal Energy Management Program. "Water-Conservation
Best Management Practices." Retrieved October 10, 2002.
http://www.eren.doe.gov/femp/techassist/best_
practices.html
Green Building Services. "Green Technology Brief: Water
Conservation." Retrieved June 14,2003.
http://greenbuildingservices.com/images/PDF/
WaterConWeb.pdf
Metropolitan Washington Council of Governments
(MWCOG). 2001. Combined Sewer Overflow Rooftop Type
Analysis and Rain Barrel Demonstration Project. Prepared
for The District of Columbia Water and Sewer Authority.
Washington DC: Metropolitan Washington Council of
Governments.
National Small Flows Clearinghouse (NSFC). 1998.
Environmental Technology Initiative Fact Sheet: Ozone
Disinfection. National Small Flows Clearinghouse Item
#WWFSGN100. Morgantown, WV, West Virginia University.
Pacific Northwest National Laboratory (PNNL). 2001.
Market Assessment for Capturing Water Conservation
Opportunities in the Federal Sector. Prepared for the US
Department of Energy Federal Energy Management
Program. Richland, WA: Pacific Northwest National
Laboratory.
Tool Base Services. "Water Conservation." Retreived October
11,2002.
http://www.toolbase.org/secondaryT.asp?TrackID=&Catego
ryID=1002
Texas Water Development Board (TWDB) and Center for
Maximum Potential Building Services (CMPBS)CMPBS.
1997. Texas Guide to Rainwater Harvesting. Austin, TX:
TWDB and CMPBS.
Inclusion of this technology description in this Report to
Congress does not imply endorsement of this technology
by EPA and does not suggest that this technology is
appropriate in all situations. Use of this technology does
not guarantee regulatory compliance. The technology
description is solely informational in intent.
LID-25
-------
Appendix M
Financial Information
M.1 Cost Escalation Factors
M.2 Past Investments in Wastewater
Infrastructure
M.3 Projected Needs for CSO Control
-------
-------
Appendix M
M.I Cost Escalation Factors
All cost information presented in this Report to Congress is in 2002 dollars unless otherwise noted. Capital costs
were adjusted using the Chemical Engineering Plant Cost Index (CEPCI); O&M Costs were adjusted using the Gross
Domestic Product Implicit Price Deflator (GDPIPD). A summary of these cost factors from 1970 to 2002 is provided
in Table M.I.
Table M.1 Cost Escalation Factors
Year Capital
1970
2002
1.0940
1.1080
M-1
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Report to Congress on Impacts and Control ofCSOs and SSOs
M-2
-------
Appendix M
M.2 Past Investments in Wastewater Infrastructure
The federal government has been investing in the nation's wastewater infrastructure since the late 19th century.
With the passage of the Clean Water Act in 1972, federal investment markedly increased, peaking in 1977. As
shown in Table M.2, between 1970 and 2000, the federal government invested more than $122 billion in the
nation's wastewater infrastructure.
Table M.2 Federal Funding for Wastewater Infrastructure, 1970 - 2000
(billions of dollars)
Construction /~w<;Rpb EPA Line Unadjusted Total
Grant3 LWi>K|- )tem Tota| (2000 Dollars)
M-3
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Report to Congress on Impacts and Control ofCSOs and SSOs
EPA estimates that current combined capital investment in wastewater infrastructure from federal, state, and
local governments is just over $13 billion annually (EPA 2002). Today, according to industry organizations,
individual utilities can pay as much as 90 percent of capital expenses (AMSA and WEE 1999). As shown in
Table M.3, capital expenditures by state and local governments have remained relatively constant since 1988;
annual O&M expenditures have more than doubled.
Table M.3 State and Local Expenditures on Wastewater Infrastructure, 1970 - 2000
(billions of dollars)
Adjusted
Year Capitala-b Capital (2002 O&Ma-b
Dollars)
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Total
$1.4
$1.7
$2.2
$2.4
$2.6
$3.6
$4.0
$4.2
$4.4
$5.6
$6.3
$6.9
$5.9
$5.8
$5.7
$5.
$6.5
$7.5
$8.3
$8.3
$8.4
$9.1
$8.9
$10.3
$8.0
$8.
$9.3
$9.6
$9.1
$9.7
$10.1
$200.2
$4.4
$5.1
$6.3
$6.6
$6.2
$7.8
$8.2
$8.1
$8.0
$9.3
$9.5
$9.2
$7.4
$7.2
$7.0
$7.2
$8.1
$9.2
$9.6
$0.4
$0.8
$1.0
$1.2
$1.4
$1.7
$2.0
$2.3
$2.8
$3.2
$3.6
$4.2
$4.9
$5.4
$5.8
$6.3
$6.8
$7.4
$8.0
Adjusted
O&M (2002
Dollars)
$1.6
$3.0
$3.5
$4.1
$4.4
$4.9
$5.4
$5.7
$6.5
$6.9
$7.1
$7.6
$8.3
$8.7
$9.0
$9.5
$8.7
$10.0
$11.0
$11.4
$12.4
$13.6
$14.7
$15.3
$16.1
$16.6
$17.3
$18.0
$234.4
$10.0
$10.6
$11.1
$11.6
$12.9
$13.6
$13.8
$14.6
$15.7
$16.6
$17.0
$17.5
$17.8
$18.3
$18.7
$316.0
Total
(2002
Dollars)
$6.0
$8.0
$9.9
$10.7
$10.6
$12.7
$13.6
$13.9
$14.5
««*
$16.7
$16.8
$20.9
$22.2
$23.6
$23.6
$26.0
$24.3
$25.9
$26.6
$27.3
$27.0
$28.1
$28.8
$276.9
a U.S. Census Bureau. 2003. State and Local Government Finances by Level of Government. Retrieved October 2003.
http://www.census.gov/govs/www/estimate.html.
" EPA. 2000. Office of Water and Office of Policy, Economics, and Innovation. "A Retrospective Assessment of the
Costs of the Clean Water Act:1972 to 1997. Final Report." Retrieved October 2,2003.
http://www.epa.gov/ost/economics/costs.pdf
M-4
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Appendix M
Many municipalities have made significant investments in CSO control within their jurisdictions. As part of
the data gathering for this report, EPA was able to document expenditures on CSO control in 48 communities.
To date, these expenditures total more than $6 billion, ranging from $134,000 to $2.2 billion per community.
(Table M.4)
Table M.4 Community Expenditures on CSO Control
CA
DC
GA
IA
IA
IL
IL
IL
IL
IL
IL
IL
IN
KY
MA
MA
MA
MA
ME
ME
ME
Community
San Francisco,CA
Washington, D.C.
Atlanta, GA
Columbus, GA
Burlington, IA
Washington, IA
Alton, IL
Chicago, IL
City of Batavia,IL
Decatur,IL
Galesburg, IL
Havana, IL
Lincoln, IL
Goshen,IN
Hammond,
Muncie,IN
Louisville, KY
Agawam,MA
Fitchburg,MA
MWRA, Boston, MA
South Hadley,MA
Biddeford,ME
Hamden,ME
South Portland, ME
Armada,Ml
Rouge River,Ml
Saginaw,MI
East Lansing,MI
Scottvile,MI
Capital
Expenditure
$1,450.0
$35.0b
$759.0
Annual
O&M ($M)
$20.3
$13.7
$0.3
Sources
EPA 2001, EPA 2003
EPA 2001
EPA 2001
EPA 2001, AMSA 2003
EPA 2001
CSO Municipal Interview
CSO Municipal Interview
EPA2001,EPA2003
CSO Municipal Interview
CSO Municipal Interview
CSO Municipal Interview
CSO Municipal Interview
CSO Municipal Interview
CSO Municipal Interview
CSO Municipal Interview
EPA 2001
EPA 2001
CSO Municipal Interview
CSO Municipal Interview
EPA 2001, EPA 2003
CSO Municipal Interview
CSO Municipal Interview
CSO Municipal Interview
EPA 2001
CSO Municipal Interview
EPA 2001
EPA 2001, EPA 2003
EPA 2003, CSO Municipal Interview
CSO Municipal Interview
M-5
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Report to Congress on Impacts and Control of CSOs and SSOs
Table M.4 continued
Community
MO Cape Girardeau,MO
NJ EastNewark,NJ
NJ North Bergen, NJ
NJ Perth Am boy, NJ
NY Salamanca, NY
OH Fremont, OH
OH Perrysburg,OH
OR Portland,OR
PA Altoona, PA
PA Freeland,P,
PA Wyoming Valley, PA
VA Richmond,VA
VT Randolph,VT
VT Richford,VT
VT Windsor,VT
WA Bellingham,WA
WA Bremerton,WA
WA King County,WA
WA Spokane,WA
Capital
Expenditure
Annual
O&M ($M)
Sources
CSO Municipal Interview
CSO Municipal Interview
EPA 2001
EPA 2003, CSO Municipal Interview
CSO Municipal Interview
CSO Municipal Interview
EPA 2003,CSO Municipal Interview
EPA 2001
CSO Municipal Interview
CSO Municipal Interview
CSO Municipal Interview
EPA 20C
EPA 2001
CSO Municipal Interview
CSO Municipal Interview
CSO Municipal Interview
EPA 2001
CSO Municipal Interview
EPA 2003
a Capital Expenditure reflects the total amount (in unadjusted dollars) spent by the community on CSO control.
k Includes updated information from the community's LTCP or other documents.
M-6
-------
Appendix M
M.3 Projected Needs for CSO Control
Community-specific information on projected CSO needs was available from several sources including:
• Report to Congress - Implementation and Enforcement of the CSO Control Policy
• 2000 Clean Watersheds Needs Survey Report to Congress
Together, these sources provide information on projected capital needs for CSO control in 71 communities, less than 10
percent of the CSO universe. The individual community needs, presented in Figures M.I, M.2, and M.3, total more than
$22 billion.
Figure M.1 Communities with Projected Capital Needs for CSO Control Exceeding
$100 million
$o
New York, NY
Cleveland, OH
Washington, DC
Atlanta, GA
Providence, Rl
King County, WA
Cincinnati, OH
Boston, MA
San Francisco, CA
New Haven, CT
Lynchburg, VA
Nashville & Davidson Cnty, TN
Richmond, VA
Hoboken, NJ
Manchester, NH
Lowell, MA
Akron, OH
Louisville/Jefferson Cnty, KY
Nashua, NH
Springfield, MA
Chicopee, MA
Lansing, Ml
Hartford, CT
Haverhill, MA
Wilmington, DE
Millions of Dollars
$200 $400 $600 $800 $1,000 $1,200 $1,400 $6,500
H $6,545
Data Source
^H LTCPsinEPACWNS2000
I I Other documented needs (EPA CWNS 2000)
^ Other LTCPs pending regulatory approval
M-7
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Report to Congress on Impacts and Control ofCSOs and SSOs
Figure M.2 Communities with Projected Capital Needs for CSO Control Between
$10and $100 million
$o
$20
Millions of Dollars
$40 $60
$80
$100
Cumberland, MD
Lynn, MA
Newark, NJ
Saginaw, Ml
Morgantown, WV
Everett, WA
Portsmouth, NH
Holyoke, MA
Lima, OH
Defiance, OH
Augusta, ME
Lebanon, NH
Gloucester, MA
Auburn, ME
Westernport, MD
East Lansing, Ml
Bangor, ME
Middletown, OH
Saco, ME
Waterloo, IA
Sault St. Marie, Ml
Data Source
^H LTCPsinEPACWNS2000
I I Other documented needs (EPA CWNS 2000)
^ Other LTCPs pending regulatory approval
M-8
-------
Appendix M
Figure M.3 Communities With Projected Capital Needs for CSO Control Ranging
from $735,000 to 10 million
Millions of Dollars
$0 $1 $2 $3 $4
Palmer, MA
Marion, OH
Wakefield TWP, Ml
Nitro, WV
Jacksonville, IL
Bucyrus, OH
Perrysburg, OH
Kennebec, ME
Maysville, KY
Port Clinton, OH
Lancaster, OH
Newark, OH
Juneau-Douglas, AK
Alexandria, VA
Belfast, ME
Oregon, IL
St. Joseph, Ml
Morganfield, KY
Monmouth, IL
Van Wert, OH
Catlettsburg, KY
Lewiston- Auburn, ME
Jewett City, CT
Essexville, Ml
Reynoldsville, PA
$5 $6 $7 $8 $9 $1
1
1
—
1
•
•
|
•
1
1
|
'
1
Data Source
^H LTCPsinEPACWNS2000
1 1 Other documented needs (EPA CWNS 2000)
1 1 Other LTCPs pending regulatory approval
M-9
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Report to Congress on Impacts and Control ofCSOs and SSOs
References
Association of Metropolitan Sewerage Agencies (AMSA) and Water Environment Federation (WEF).
1999. "The Cost of Clean." Retrieved March 1999.
hhtp://www.amsa-cleanwater.org/pubs/cost/coc.pdf.
EPA. 2000. Office of Water. Progress in Water Quality: An Evaluation of the National Investment in
Municipal Wastewater Treatment. EPA 832-R-00-008.
EPA. 2001. Office of Water. Report to Congress on Implementation and Enforcement of the Combined
Sewer Overflow Control Policy. EPA 833-R-01-003.
http://cfpub2.epa.gov/npdes/cso/cpolicy report.cfm.
EPA. 2002. Office of Water. The Clean Water and Drinking Water Infrastructure Gap Analysis. EPA 816-
R-02-020.
EPA. 2003. Office of Water. Clean Watersheds Needs Survey 2000 Report to Congress. EPA 832-R-03-001.
M-10
-------
References
American Federation of State, County,
and Municipal Employees (AFSCME).
2003. "Risky Business: An AFSCME
Health and Safety Guide for Water and
Wastewater Treatment Plant Workers."
Retrieved October 3,2003.
http://www.afscme.org/health/
riskybtc.htm.
American Society of Civil Engineers
(ASCE). 1997. Manhole Inspection
and Rehabilitation. Prepared by the
Committee on Manhole Rehabilitation
of the Pipeline Division of ASCE. New
York: ASCE.
ASCE. 1999. Optimization of
Collection System Maintenance
Frequencies and System Performance.
Prepared by Black & Veatch, LLP
under EPA Cooperative Agreement
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