United States Office of Research and Office of EPA/625/6-91/027
Environmental Protection Development Water Revised August 1998
Agency Washington DC 20460 Washington DC 20460
vvEPA Handbook
Optimizing Water Treatment
Plant Performance Using the
Composite Correction
Program
1998 Edition
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EPA/625/6-91/027
Revised August 1998
Handbook
Optimizing Water Treatment Plant
Performance Using the
Composite Correction Program
1998 Edition
Technical Support Center
Standards and Risk Management Division
Office of Ground Water and Drinking Water
Office of Water
Cincinnati, Ohio 45268
Center for Environmental Research Information
Technology Transfer and Support Division
National Risk Management Research Laboratory
Office of Reasearch and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
Printed on Recycled Paper
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Notice
This document has been reviewed in accordance with the U.S. Environmental
Protection Agency's peer and administrative review policies and approved for
publication. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
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Acknowledgments
This handbook was prepared for the United States Environmental Protection Agency (U.S. EPA) by
Process Applications, Inc. Although many individuals contributed to the preparation and review of this
document, the assistance of the individuals listed below is especially acknowledged.
Major Authors:
Bob A. Hegg and Larry D. DeMers, Process Applications, Inc., Fort Collins, Colorado
Jon H. Bender, Eric M. Bissonette, and Richard J. Lieberman, U.S. EPA Office of Groundwater and
Drinking Water (OGWDW) Technical Support Center (TSC), Cincinnati, Ohio
Project Managers:
James E. Smith, Jr., U.S. EPA Office of Research and Development, Technology Transfer and
Support Division, National Risk Management Research Laboratory (NRMRL)
Jon H. Bender, U.S. EPA OGWDW, TSC, Cincinnati, Ohio
Reviewers:
Frank Evans, U.S. EPA, NRMRL, Cincinnati, Ohio
Julie Z. LeBlanc, U.S. Army Corps of Engineers, New Orleans, Louisiana
David Parker, U.S. EPA, Region IV, Atlanta, Georgia
Chuck Schwarz, Texas Natural Resource Conservation Commission, Tyler, Texas
Jeff Robichaud, U.S. EPA, OGWDW, Washington, D.C.
Editing and Production:
M. Lynn Kelly, Process Applications, Inc., Fort Collins, Colorado
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Contents
Chapter Page
Acknowledgments iii
List of Figures x
List of Tables xi
1 Introduction 1
1.1 Purpose 1
1.2 Background 1
1.2.1 Wastewater Treatment Compliance 1
1.2.2 Water Treatment Optimization 2
1.2.3 Broad-Scale Application of CCP Concepts 2
1.3 Scope 3
1.3.1 Update of the CCP Approach and Implementation 3
1.3.2 Support for Future Regulations 3
1.3.3 Technical Resource for the Partnership for Safe Water 4
1.3.4 Considerations for Total System Optimization 4
1.4 Using the Manual 4
1.5 References 4
2 Protection Of Public Health From Microbial Pathogens 7
2.1 Background 7
2.2 Waterborne Disease History 7
2.3 Relationship Between Optimized Performance and Public Health Protection 8
2.3.1 Multiple Barrier Strategy 3
2.3.2 Basis for Optimization Goals 9
2.4 Optimization Performance Goals 10
2.4.1 Minimum Data Monitoring Requirements 10
2.4.2 Individual Sedimentation Basin Performance Goals 10
2.4.3 Individual Filter Performance Goals 10
2.4.4 Disinfection Performance Goal 11
2.5 Role of the Water Treatment Plant Staff in Public Health Protection 11
2.6 References 11
3 Assessing Composite Correction Program Application 13
3.1 Introduction 13
3.2 Optimization Program Experience 13
3.3 Area-Wide Optimization Model 14
3.3.1 Status Component 14
3.3.2 Evaluation Component 14
3.3.3 Follow-Up Component 14
3.3.4 Maintenance Component 14
3.4 Implementation of an Area-Wide Model 14
3.4.1 Establish Criteria to Prioritize Water Systems 16
3.4.2 Assess Water System Performance Relative to Optimization Goals -16
3.4.3 Prioritize Water Systems Based on Selected Criteria 17
3.4.4 Assess Response to Prioritized Water Systems 18
3.5 References 19
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Con tents (continued)
Chapter Page
4 Comprehensive Performance Evaluation 21
4.1 Introduction 21
4.2 CPE Methodology 21
4.2.1 Assessment of Plant Performance 21
4.2.1 .1 Review and Trend Charting of Plant Operating Records --21
4.2.1.2 Supplemental Data Collection 22
4.2.2 Evaluation of Major Unit Processes 25
4.2.2.1 Overview 25
4.2.2.2 Approach 27
4.2.2.3 Determining Peak Instantaneous Operating Flow 28
4.2.2.4 Rating Individual Unit Processes 29
Flocculation 30
Sedimentation 30
Filtration 31
Disinfection 32
Post-Disinfection 32
Pre-Disinfection 34
4.2.3 Identification and Prioritization of Performance Limiting Factors 35
4.2.3.1 Identification of Performance Limiting Factors 35
Identification of Administrative Factors -36
Policies 37
Budgeting 38
Staffing 38
Identification of Design Factors 38
Identification of Operational Factors 39
Plant Flow Rate and Number of Basins in Service .39
Chemical Dose Control 39
Filter Control 40
Process Control Activities 41
Other Controls 42
Identification of Maintenance Factors 42
4.2.3.2 Prioritization of Performance Limiting Factors 42
4.2.4 Assessment of the Applicability of a CTA 44
4.2.5 CPE Report 44
4.3 Conducting a CPE 44
4.3.1 Overview 49
4.3.2 Initial Activities 49
4.3.2.1 Key Personnel 50
4.3.2.2 CPE Resources 50
4.3.2.3 Scheduling 50
4.3.3 On-Site Activities 51
4.3.3.1 Kick-Off Meeting 51
4.3.3.2 Plant Tour 51
Pretreatment 52
Mixing/Flocculation/Sedimentation 52
Chemical Feed Facilities 53
Filtration 53
Disinfection 54
Backwash Water and Sludge Treatment and Disposal -.54
Laboratory 54
Maintenance 54
vi
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Con tents (continued)
Chapter Page
4.3.3.3 Data Collection Activities 54
4.3.3.4 Evaluation of Major Unit Processes 55
4.3.3.5 Performance Assessment .55
4.3.3.6 Field Evaluations 55
4.3.3.7 Interviews 57
4.3.3.8 Evaluation of Performance Limiting Factors.. 57
4.3.3.9 Exit Meeting 58
4.3.4 CPE Report 60
4.4 Case Study 60
4.4.1 Facility Information 60
4.4.2 Performance Assessment 61
4.4.3 Major Unit Process Evaluation 61
4.4.3.1 Flocculation Basin Evaluation 61
4.4.3.2 Sedimentation Basin Evaluation 62
4.4.3.3 Filter Evaluation 62
4.4.3.4 Disinfection Process Evaluation 62
4.4.4 Performance Limiting Factors 63
4.4.5 Assessing Applicability of a CTA 64
4.4.6 CPE Results 64
4.5 References 64
5 Comprehensive Technical Assistance 67
5.1 Objective.. 67
5.2 Conducting CTAs 68
5.2.1 Overview 68
5.2.2 Implementation 69
5.2.2.1 Approach 70
CTA Facilitator 70
On-Site CTA Champion 71
CTA Framework 71
5.2.2.2 Tools -73
Contingency Plans 73
Action Plans 73
Special Studies 73
Operational Guidelines 74
Data Collection and Interpretation .74
Priority Setting Tools 75
Topic Development Sheets 75
Internal Support 76
What If Scenarios 77
5.2.2.3 Correcting Performance Limiting Factors 77
Design Performance Limiting Factors -77
Maintenance Performance Limiting Factors -78
Administrative Performance Limiting Factors 78
Operational Performance Limiting Factors 79
Process Sampling and Testing -.80
Chemical Pretreatment and Coagulant Control -80
Unit Process Controls 82
VII
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Con tents (continued)
Chapter Page
5.3 Case Study 85
5.3.1 CPE Findings 85
5.3.2 CTA Activities 86
5.3.2.1 Initial Site Visit 86
5.3.2.2 Off-Site Activities 87
5.3.2.3 Follow-Up Site Visit 87
5.3.2.4 Other CTA Activities 88
5.3.2.5 CTA Results 88
5.4 References ••• 91
6 Findings From Field Work 93
6.1 Introduction 93
6.2 Results of Comprehensive Performance Evaluations 93
6.2.1 Major Unit Process Capability 93
6.2.2 Factors Limiting Performance 94
6.2.3 Summary of CPE Findings 96
6.3 Results of Comprehensive Technical Assistance Projects 97
6.4 References 98
7 The Future: Changing Regulations and New Optimization Challenges 99
7.1 Introduction 99
7.2 Background on M-DBP Regulations 99
7.3 M-DBP Requirements Relative to Optimized Performance Goals 100
7.3.1 Treatment Technique Turbidity Requirements 100
7.3.2 Removal/lnactivation Requirements 101
7.3.3 DBP Maximum Contaminant Levels (MCLs) 102
7.3.4 Enhanced Coagulation Requirements .103
7.3.5 Microbial Backstop 103
7.4 Summary 104
7.5 References 105
8 Other CCP Considerations 107
8.1 Introduction 107
8.2 Developing CCP Skills 107
8.2.1 CPE Training Approach 107
8.2.2 CTA Training Approach 107
8.3 Quality Control 108
8.3.1 CPE Quality Control Guidance 108
8.3.2 CTA Quality Control Guidance 109
8.4 Total System Optimization 110
8.5 References 112
VIII
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Con tents (continued)
Appendices Page
Appendix A Data Collection Spreadsheets and Macros for the Partnership for Safe Water 115
Appendix B Drinking Water Treatment Plant (DWTP) Advisor Software 1 123
Appendix C Major Unit Process Capability Evaluation Performance Potential Graph
Spreadsheet Tool for the Partnership for Safe Water /. 125
Appendix D CT Values for Inactivation of Giardia and Viruses by Free Cl, and Other
Disinfectants *....* * 135
Appendix E Performance Limiting Factors Summary Materials and Definitions 145
Appendix F Data Collection Forms 159
Appendix G Example CPE Report 205
Appendix H Example CPE Scheduling Letter.. 221
Appendix I Example Special Study 225
Appendix J Example Operational Guideline 227
Appendix K Example Process Control Daily Report.. 231
Appendix L Example Jar Test Guideline 233
Appendix M Chemical Feed Guidelines 237
Appendix N Conversion Chart * * . ..* 245
IX
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List of Figures
Chapter
Figure 2-1.
Figure 3-1.
Figure 3-2.
Figure 3-3.
Figure 4-1.
Figure 4-2.
Figure 4-3.
Figure 4-4.
Figure 4-5.
Figure 4-6.
Figure 4-7.
Figure 4-8.
Figure 4-9.
Figure 4-1 0.
Figure 5-1.
Figure 5-2.
Figure 5-3.
Figure 5-4.
Figure 5-5.
Figure 5-6.
Figure 5-7.
Figure 5-8.
Figure 5-9.
Figure 5-1 0.
Figure 5-1 1.
Figure 5-I 2.
Figure 5-I 3.
Figure 7-I.
Figure 7-2.
Page
Multiple barrier strategy for microbial contaminant protection 9
Area-wide optimization model 15
Area-wide treatment plant performance status 16
Example turbidity monitoring data for 12-month period 18
Example performance assessment trend charts 23
Example of individual filter monitoring .25
Major unit process evaluation approach 26
Example performance potential graph .27
Major unit process rating criteria 28
Example factors summary and supporting notes 45
CPE/CTA schematic of activities 47
Schematic of CPE activities 48
Flow schematic of Plant A 60
Performance potential graph for Plant A 61
CTA results showing finished water quality improvements 67
CTA priority setting model 68
Schematic of CTA framework 72
Example action plan 73
Special study format 74
Short term trend chart showing relationship of raw, settled and filtered
water turbidities
75
Example priority setting results from CTA site visit activity ..76
Example topic development sheet 76
A basic process control sampling and testing schedule 81
Performance improvement during CTA project - filter effluent -89
Performance improvement during CTA project - sedimentation basin effluent 89
Performance improvement during CTA project - filter backwash spikes -90
Plant performance after CTA 90
Historic perspective of turbidity goal and regulations 101
Example of disinfection profile daily variations in log inactivation .104
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List of Tables
Number
Table l-l.
Table 2-1.
Table 3-1.
Table 3-2.
Table 4-1.
Table 4-2.
Table 4-3.
Table 4-4.
Table 4-5.
Table 4-6.
Table 6-1.
Table 6-2.
Table 6-3.
Table 8-I.
Table 8-2.
Table 8-3.
Table 8-4.
Page
Information Pertinent to Specific User Groups 5
U.S. Outbreaks of Cryptosporidiosis in Surface Water Supplies.. 8
Example Prioritization Criteria for Surface Water Systems 17
Example Prioritization Database 18
Percentile Distribution Analysis of Water Quality Data.. 24
Major Unit Process Evaluation Criteria 29
Expected Removals of Giardia Cysts and Viruses by Filtration 33
Factors for Determining Effective Disinfection Contact Time Based on
Basin Characteristics
34
Classification System for Prioritizing Performance Limiting Factors.. 43
Evaluation Team Capabilities 49
Geographical Distribution of CPEs and CTAs 93
Summary of the Major Unit Process Ratings for 69 Plants 94
Most Frequently Occurring Factors Limiting Performance at 69 CPEs 95
Training Approach to Achieve Transfer of CPE Skills 108
Quality Control Checklist for Completed CPEs 109
Quality Control Checklist for Completed CTAs 110
Total System Optimization Considerations for Drinking Water Utilities 111
XI
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Chapter 1
Introduc tion
1 .1 Purpose
Maintaining public health protection at water sup-
ply systems has become more challenging in
recent years with the resistance of some patho-
gens to disinfection using chlorination and an
increase in the immuno-compromised population
(e.g., people with HIV, organ transplant patients,
the elderly). Also, as evidenced by recent out-
breaks, compliance with the 1989 Surface Water
Treatment Rule (SWTR) does not always assure
maximum protection of the public from waterborne
disease (1). Based on this awareness, the U.S.
Environmental Protection Agency (USEPA) is
developing regulations to control contamination
from microbial pathogens in drinking water while
concurrently addressing other concerns such as
disinfection by-products (2,3). These new and
interrelated regulations are moving the water sup-
ply industry toward meeting increasingly more
stringent water treatment requirements.
Research and field work results support optimizing
particle removal from water treatment facilities to
maximize public health protection from microbial
contamination (4,5,6). Since 1988 the Composite
Correction Program (CCP) has been developed and
demonstrated as a method of optimizing surface
water treatment plant performance with respect to
protection from microbial pathogens in the United
States and Canada (7,8). The approach is based
on establishing effective use of the available water
treatment process barriers against passage of par-
ticles to the finished water.
Specific performance goals are used by the CCP
approach to define optimum performance for key
treatment process barriers such as sedimentation,
filtration, and disinfection. These include a maxi-
mum individual sedimentation basin effluent tur-
bidity goal of less than 2 nephelometric turbidity
units (NTUs) to assure that the integrity of this
barrier is consistently maintained and to provide a
low particle loading to the filters. For the filtration
barrier, optimum performance has been described
as individual filter effluent turbidities of less than
0.1 NTU with a maximum post backwash "spike"
to 0.3 NTU and returning to less than 0.1 NTU in
less than 15 minutes. The disinfection goal has
been based on achieving the log inactivation
requirement for Giardia and/or viruses described in
the SWTR guidance (9).
This handbook is an updated version of the USEPA
Handbook: Optimizing Water Treatment Plant Per-
formance Using the Composite Correction Program
published in 1991 (7). It is intended to serve as a
resource document for optimizing the performance
of existing surface water treatment facilities to
provide protection from microbial contamination.
1.2 Background
7.2.7 Wastewater Treatment Compliance
The CCP approach was initially developed to
address compliance problems at wastewater
treatment facilities that were constructed in the
late 1960's and 1970's. A survey involving over
one hundred facilities was conducted to identify
the reasons for this non-compliance (10,1 1 j 2).
The survey revealed that operations and mainte-
nance factors were frequently identified as limiting
plant performance, but also disclosed that adminis-
trative and design factors were contributing limita-
tions. Most importantly, each plant evaluated had
a unique list of factors limiting performance.
Based on these findings, an approach was devel-
oped to identify and address performance limita-
tions at an individual facility and to obtain
improved performance. Significant success was
achieved in improving performance at many
wastewater treatment facilities without major capi-
tal improvements (13). Ultimately, a handbook
was developed that formalized the evaluation and
correction procedures (14). The formalized
approach was defined as the Composite Correction
Program (CCP), and it consists of two compo-
nents-a Comprehensive Performance Evaluation
(CPE) and Comprehensive Technical Assistance
(CTA). As a point of clarification, the technical
assistance phase was initially referred to as a
Composite Correction Program; however, the
name of this phase was changed to Comprehen-
sive Technical Assistance to better differentiate
the two phases. A CPE is a thorough review and
analysis of a plant's performance-based capabili-
ties and associated administrative, operation, and
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maintenance practices. It is conducted to identify
factors that may be adversely impacting a plant's
ability to achieve permit compliance without major
capital improvements. A CTA is the performance
improvement phase that is implemented if the CPE
results indicate improved performance potential.
During the CTA phase, identified plant-specific fac-
tors are systematically addressed and eliminated.
The wastewater CCP handbook was updated in
1989 to include specific low cost modifications
that could be used to optimize an existing facility's
performance (15). An "expert system" (POTW
Expert) was also developed to supplement the
handbook (1 6).
7.2.2 Water Treatment Optimization
Based on the state of Montana's successful use of
the CCP approach for improving compliance of
their mechanical wastewater treatment facilities,
state personnel evaluated the feasibility of using
the CCP to optimize the performance of small sur-
face water treatment facilities. With financial
assistance from USEPA Region 8, nine CPEs and
three CTAs were completed from April 1988 until
September 1990. Through these efforts, each of
the existing facilities where CTAs were imple-
mented showed dramatic improvements in the
quality of finished water turbidity. Additionally,
improved performance was achieved at three
plants where only the evaluation phase (CPE) of
the program was completed (17). The encourag-
ing results from Montana's adoption of the CCP
approach to surface water treatment plants led to
the USEPA's Office of Ground Water and Drinking
Water involvement with the program in 1989.
USEPA decided to further develop and demon-
strate use of the CCP approach as it applied to
compliance with drinking water regulations to
ensure its applicability nation-wide. In pursuit of
this goal, a cooperative project was initiated
between USEPA's Office of Ground Water and
Drinking Water, Technical Support Center (TSC)
and Office of Research and Development, Tech-
nology Transfer and Support Division, National
Risk Management Research Laboratory (NRMRL).
This project provided resources to: conduct an
additional twelve CPEs in the states of Ohio,
Kentucky, West Virginia, Maryland, Montana,
Vermont, and Pennsylvania; prepare a summary
report (8); and develop a water CCP Handbook
(7).
Following these initial efforts, work continued,
through a cooperative agreement between TSC
and the University of Cincinnati, on further refine-
ment and development of the CCP approach. For-
mal efforts were implemented to incorporate the
CCP into state programs. It was anticipated that
application of the CCP by state regulatory person-
nel would achieve desired performance levels with
a minimum financial impact on the utilities in their
jurisdiction. Pilot programs were implemented in
eight states (West Virginia, Massachusetts,
Maryland, Rhode Island, Kentucky, Pennsylvania,
Texas, and Colorado) which focused on develop-
ing CPE capability for state staff. A progressive
training process was developed within each state.
The training process included the completion of a
seminar followed by three CPEs conducted by a
state core team that was facilitated by USEPA and
Process Applications, Inc. Similar pilot programs
were also completed in USEPA Regions 6 and 9.
Typically, state regulatory staff selected the CPE
candidate plants based on their perception of the
plant's inability to meet .the SWTR turbidity
requirements.
The progressive training approach proved to be
successful; however, other issues and challenges
related to implementation within the existing state
regulatory program structure became apparent.
As the state pilot programs progressed, these
challenges to implementation became known col-
lectively as institutional barriers. The impact of
institutional barriers on state-wide optimization
efforts is discussed further in Chapter 3.
7.2.3 Broad-Scale Application of CCP
Concepts
The optimization concepts included within the CCP
approach have been expanded to a variety of
water industry and regulatory activities. A partial
list of current optimization efforts that utilize com-
ponents of the CCP is described below.
. The states of Alabama, Georgia, Kentucky,
and South Carolina, in cooperation with EPA
Region 4, are currently pursuing a multi-state
effort that focuses on optimization of their sur-
face water treatment facilities through a pilot
program based on the application of the CCP
concepts and tools.
• The Partnership for Safe Water is a voluntary
program for enhancing water treatment to
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provide higher quality drinking water. Organiza-
tions involved in the Partnership include the U.S.
Environmental Protection Agency, American Water
Works Association, Association of Metropolitan
Water Agencies, National Association of Water
Companies, Association of State Drinking Water
Administrators, and the American Water Works
Association Research Foundation. The Partnership
utilized the CCP as the basis of its Phase III com-
prehensive water treatment self-assessment (18).
Use of the CCP is also being considered for the
Phase IV third party assessment of participating
utilities. As of, May 1998, 217 water utilities
serving nearly 90 million people are participating in
the Partnership for Safe Water.
• In 1996 the American Water Works Associa-
tion Research Foundation conducted an opti-
mization workshop with national water quality
and treatment experts from throughout the
industry. As a result of this workshop, a self-
assessment handbook was published by
AWWARF (19). This handbook, which follows
the CCP approach, is intended to be a resource
for water utilities that choose to conduct a
self-assessment to improve performance.
• An expanded discussion of the relationship
between optimized performance and public
health protection.
• An expanded definition of optimized perform-
ance goals for microbial contaminant protec-
tion.
• Considerations for selection of CPE and CTA
candidates.
• Clarification on CCP terminology.
• Description and use of the Partnership for Safe
Water software for compiling and analyzing
turbidity data.
• Updated process criteria for completing the
major unit process evaluation.
• An updated database of completed CPEs and
CTAs and a summary of typical factors found
limiting performance.
• Streamlined forms for collection of field data.
1.3 Scope
Since publication of the predecessor of this hand-
book in 1991, several modifications have been
made to the CCP and its use for optimizing surface
water treatment plants. In addition, other com-
plementary drinking water optimization activities
(e.g., Partnership for Safe Water) have developed
and continue to have positive impacts in this area.
The purpose of this handbook update is to incor-
porate new information and to integrate the other
complementary programs.
1.3.1 Update of the CCP Approach and
Implementation
Experience gained from over 70 CPEs and 9 CTAs
provides the basis for updating the CCP approach
presented in this handbook. In addition, eight
state pilot programs have provided the basis for
the area-wide application of the CCP. Significant
additions and modifications to the CCP included in
this handbook are:
7.3.2 Support for Future Regulations
The initial CCP handbook focused on meeting the
requirements of the Surface Water Treatment Rule
(SWTR) (20). As the challenges of protecting the
public health from microbial contamination became
more paramount, the emphasis was shifted from
the SWTR requirements to achieving optimized
performance goals.
Pursuant to the requirements under the 1996
Amendments to the Safe Drinking Water Act
(SDWA), the USEPA is developing interrelated
regulations to control microbial pathogens and
disinfectants/disinfection byproducts in drinking
water, collectively known as the micro-
bial/disinfection byproducts (M/DBP) rules. The
1996 Amendment to the SDWA set a deadline for
promulgation of the Interim Enhanced Surface
Water Treatment Rule (IESWTR) of November
1998. USEPA's Notice of Data Availability (3)
indicates that this rule will include a revised fin-
ished water turbidity requirement of 0.3 NTU, new
individual filter monitoring requirements, and
requirements for states to have authority to
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require the conduct of CCPs for water utilities that
experience difficulties in meeting the turbidity
requirements of the rule. This handbook is
intended to provide a technical resource to support
the implementation of the IESWTR.
7.3.3 Technical Resource for the Partnership
for Safe Water
This updated handbook is also intended to comple-
ment and enhance the existing Partnership for
Safe Water documentation and program activities.
In addition to supporting the ongoing Phase III
self-assessment activities, the handbook will also
support the anticipated Phase IV activities. A
possible Phase IV approach could involve an inde-
pendent third party review of a utility using the
CCP format. This final step in the Partnership
process ensures that some of the potential limita-
tions of self-assessment (e.g., difficulty in identi-
fying operational and administrative factors) are
not overlooked.
7.3.4 Considerations for Total System
Optimization
Although this handbook is intended to be a techni-
cal resource for surface water treatment facilities
to pursue optimized performance for protection
against microbial contamination, it is recognized
that as the regulations change and optimum per-
formance is pursued, the focus of optimization
activities will expand to other parameters. Antici-
pated future areas for optimization include source
water protection, disinfection by-products, corro-
sion control, groundwater disinfection, and distri-
bution system water quality. This expanded scope
is called total system optimization. Minor addi-
tions are included in this handbook to address
some of these areas; however, future handbook
modifications or additional handbooks are envi-
sioned to more thoroughly address total system
optimization concepts and topics.
1.4 Using the Manual
The primary intended users of this handbook
include regulators (e.g., federal and state agency
personnel) and non-regulators (e.g., utility person-
nel and consultants). To facilitate the use of this
handbook, information has been separated into the
following chapters:
• Chapter 1 - Introduction
• Chapter 2 - Protection of Public Health
from Microbial Pathogens
• Chapter 3 - Assessing Composite Correc-
tion Program Application
• Chapter 4 - Comprehensive Performance
Evaluations
Chapter 5 - Comprehensive Technical
Assistance
• Chapter 6 - Findings From Field Work
Chapter 7 - Current and Future Regulation
Impacts on Optimization
Chapter 8 - Other CCP Considerations
Table l-l provides guidance on where specific
user groups can locate within this handbook
information that is considered pertinent to their
unique interest or intended use.
1.5 References
When an NTIS number is cited in a reference, that
reference is available from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650
1. Kramer, M.H., et al. 1996. "Waterborne
Disease: 1993 and 1994." Journal AWWA,
88(3):66.
2. USEPA. 1997. National Primary Drinking
Water Regulations: Disinfectants and Disinfec-
tion Byproducts; Notice of Data Availability;
Proposed Rule. Fed. Reg., 62:212:59338
(November 3, 1997).
3. USEPA. 1997. National Primary Drinking
Water Regulations: Interim Enhanced Surface
Water Treatment Rule Notice of Data
Availability; Proposed Rule. Fed. Reg.,
62:212:59486 (November 3, 1997).
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Table 1-1. Information Pertinent to Specific User Groups
User
Purpose
Chapter
Source
USEPA/State
Regulatory
Personnel
• Assess application of the CCP as part of an area-wide
optimization strategy
• Identify priority plants for CCP application
• Review/learn the CPE protocol
. Review/learn the CTA protocol
. Review CCP database for common factors limiting
performance
. Review quality control criteria for assessment of third
party CCPs
=> Chapter 3
=> Chapter 3
=> Chapter 4
=> Chapter 5
=> Chapter 6
=> Chapter 8
Utility
Personnel
• Utilize the CCP as a self-assessment resource
• Assess capabilities of CCP providers
Chapters
4& 5
Chapter 8
Consultants/
Peer Assessment
Team Members
. Review/learn the CPE protocol
• Review/learn the CTA protocol
• Review CCP database for common factors limiting
performance
Chapter 4
Chapter 5
Chapter 6
4. Patania, N.L., et al. 1996. Optimization of Fil-
tration for Cvst Removal. AWWARF, Denver,
CO.
5. Nieminski, E.G., et al. 1995. "Removing
Giardia and Cryptosporidium by Conventional
Treatment and Direct Filtration." Journal
AWWA, 87(9):96.
6. Consonery, P.J., et al. 1996. "Evaluating and
Optimizing Surface Water Treatment Plants:
How Good is Good Enough?" Paper presented
at
AWWA Water Quality Technology Conference,
Boston, MA.
7. Renner, R.C., B.A. Hegg, J.H. Bender, and
E.M. Bissonette. 1991. Qptimizina Water
Treatment Plant Performance Usina the Com-
posite Correction Proaram. EPA/625/6-
91/027, USEPA Center for Environmental
Research Information, Cincinnati, OH.
8. Renner, R.C., B.A. Hegg, and J.H. Bender.
1990. Summary Report: Qptimizina Water
Treatment Plant Performance With the Com-
posite Correction Proaram. EPA 625/8-
90/01 7, USEPA Center for Environmental
Research Information, Cincinnati, OH.
9. Guidance Manual for Compliance With the Fil-
tration and Disinfection Reauirements for Pub-
lic Water Systems Usina Surface Water
Sources. 1989. NTIS No. PB-90148016,
USEPA, Cincinnati, OH.
10. Hegg, B.A., K.L. Rakness, and J.R. Schultz.
1979. Evaluation of Operation and Mainte-
nance Factors Limitina Municipal Wastewater
Treatment Plant Performance. EPA 600/2-79-
034, NTIS No. PB-300331, USEPA, Municipal
Environmental Research Laboratory, Cincinnati,
OH.
-------
11. Gray, A.C., Jr., P.E. Paul, and H.D. Roberts.
1979. Evaluation of Operation and Mainte-
nance Factors Limitina Bioloaical Wastewater
Treatment Plant Performance. EPA 600/2-79-
087, NTIS No. PB-297491, USEPA, Municipal
Environmental Research Laboratory, Cincinnati,
OH.
12. Hegg, B.A., K.L. Rakness, J.R. Schultz, and
L.D. DeMers. 1980. Evaluation of Operation
and Maintenance Factors Limitina Municipal
Wastewater Treatment Plant Performance -
Phase II. EPA 600/2-80-I 29, NTIS No. PB-81-
1 12864, USEPA, Municipal Environmental
Research Laboratory, Cincinnati, OH.
13. Hegg, B.A., K.L. Rakness, and J.R. Schultz.
1979. A Demonstrated Approach for Improv-
ing Performance and Reliability of Bioloaical
Wastewater Treatment Plants. EPA 600/2-79-
035, NTIS No. PB-300476, USEPA, Cincinnati,
OH.
14. Hegg, B.A., J.R. Schultz, and K.L. Rakness.
1984. EPA Handbook: Imorovina POTW Per-
formance Usina the Composite Correction Pro-
gram Approach. EPA 625/6-84-008, NTIS No.
PB-88184007, USEPA Center for Environ-
mental Research Information, Cincinnati, OH.
15. Hegg. B.A., L.D. DeMers, and J.B. Barber.
1989. EPA Technoloav Transfer Handbook:
Retrofittina POTWs. EPA 625/6-89-020, NTIS
No. PB-90182478, USEPA Center for Envi-
ronmental Research Information, Cincinnati,
OH.
16. Publicly Owned Treatment Works Expert Users
Guide and Software. 1990. Eastern Research
Group, Inc. and Process Applications, Inc. for
USEPA Center for Environmental Research
Information, Cincinnati, OH.
17. Renner, R.C., B.A. Hegg, and D.L. Fraser.
1989. "Demonstration of the Comprehensive
Performance Evaluation Technique to Assess
Montana Surface Water Treatment Plants."
Presented at the 4th Annual ASDWA Confer-
ence, Tucson, AZ.
18. Bender, J.H., R.C. Renner, B.A. Hegg, E.M.
Bissonette, and R. Lieberman. 1995. "Part-
nership for Safe Water Voluntary Water
Treatment Plant Performance Improvement
Program Self-Assessment Procedures."
USEPA, AWWA, AWWARF, Association of
Metropolitan Water Agencies, Association of
State Drinking Water Administrators, and
National Association of Water Companies.
19. Renner, R.C., and B.A. Hegg. 1997. Self-
Assessment Guide for Surface Water Treat-
ment Plant Optimization. AWWARF, Denver,
co.
20. USEPA. 1989. Surface Water Treatment
Rule. Fed. Reg., 54:124:27486 (June 29,
19891.
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Chapter 2
Protection of Public Health From Microbial Pathogens
2.1 Background
One of the major objectives of water supply sys-
tems is to provide consumers with drinking water
that is sufficiently free of microbial pathogens to
prevent waterborne disease. Water supply sys-
tems can achieve this level of public health protec-
tion by providing treatment to assure that patho-
gens found in the raw water supply are removed
or inactivated. The relationship between optimized
water treatment plant performance and protection
of public health from microbial pathogens is pre-
sented in this chapter.
2.2 Waterborne Disease History
Several well documented disease outbreaks that
were associated with the use of untreated surface
water, contaminated well water, treatment plant
deficiencies, and contaminated distribution sys-
tems have occurred over the past 20 years. Dur-
ing this period the most common suspected
causes of waterborne disease outbreaks were the
protozoan parasites Giardia lamblia and Cryptospo-
ridium parvum ( 1). These parasites exist in the
environment in an encysted form where the infec-
tious material is encapsulated such that they are
resistant to inactivation by commonly used disin-
fectants. These parasites are transmitted to their
hosts by ingestion of cysts that have been
excreted in the feces of infected humans or ani-
mals. Infection can occur through ingestion of
fecally contaminated water or food or contact with
fecally contaminated surfaces. Recent studies
have indicated that these parasites are routinely
detected in surface water supplies throughout
North America (2,3,4). They can enter surface
water supplies through natural runoff, wastewater
treatment discharges, and combined sewer over-
flows,
A recent review of waterborne disease in the U.S.
during the period 1993 through 1994 identified 30
disease outbreaks associated with drinking water.
The outbreaks caused over 400,000 people to
become ill-the majority from a 1993 outbreak in
Milwaukee. Twenty-two of the outbreaks were
known or suspected to be associated with infec-
tious agents and eight with chemical contami-
nants. Giardia or Cryptosporidium was identified
as the causative agent for 10 of the outbreaks,
and six of these systems were associated with a
surface water source. All six systems provided
chlorination, and four also provided filtration. In
the filtered systems, deficiencies in the distribution
system were identified for one outbreak, inade-
quate filtration for one, and no apparent deficien-
cies were identified in two cases (1).
Cryptosporidium presents a unique challenge to
the drinking water industry because of 'its resis-
tance to chlorination and its small size, making it
difficult to remove by filtration. Cryptosporidiosis
is the diarrheal illness in humans caused by Cryp-
tosporidium parvum. Cryptosporidiosis outbreaks
from surface water supplies have been docu-
mented in the United States, Canada and Great
Britain (5,6,7). A summary of U.S. outbreaks
associated with surface water supplies is shown in
Table 2-1. Five of the outbreaks were associated
with filtered drinking waters. Three systems
(Carroll, Jackson - Talent, and Milwaukee) were
experiencing operational deficiencies and high fin-
ished water turbidities at the time of the out-
breaks. All three plants utilized conventional
treatment processes that included rapid mix, floc-
culation, sedimentation, and filtration. The Clark
County outbreak was the only outbreak associated
with a filtered drinking water for which no appar-
ent treatment deficiencies were noted. All five
systems were in compliance with the federal
drinking water regulations in effect at that time.
Recent research has shown that free chlorine and
monochloramine provide minimal disinfection of
Cryptosporidium oocysts at the dosage and deten-
tion time conditions found at most treatment facili-
ties (8). Disinfection requirements based on CT in
the 1989 SWTR guidance were developed solely
on inactivation of Giardia lamblia cysts. Research
conducted by Finch (9) showed approximately
0.2 log or less inactivation of Cryptosporidium
when free chlorine was used alone (5 to 15 mg/L
@ 60 to 240 min.). Monochloramine was slightly
more effective than free chlorine. Inactivation of
Cryptosporidium through the use of stronger
disinfectants (e.g., ozone, chlorine dioxide) and
combined disinfectants is currently being
investigated by the water industry and research
institutions.
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Table 2-1. U.S. Outbreaks of Cryptosporidiosis in Surface Water Supplies {5}
Location
Bernalillo County, New Mexico
Carroll County, Georgia
Jackson County, Oregon
Milwaukee County, Wisconsin
Cook County, Minnesota
Clark County, Nevada
Year
1986
1987
1992
1993
1993
1994
Type of System
Untreated surface water supply
Treated surface water supply
Medford - chlorinated spring
Talent - treated surface water
Treated surface water supply
Treated surface water supply
Treated surface water supply
Estimated
Number of
Cases
78
13,000
15,000
403,000
27
78
The recent incidence of waterborne disease associ-
ated with protozoan parasites and the resistance
of some pathogens to conventional disinfection
presents a challenge to the water industry. Use of
a single barrier, such as disinfection alone, or
operation of a conventional treatment plant that
had not been optimized has contributed to several
disease outbreaks. For surface supplied filtration
plants, minimizing consumer's risk from microbial
pathogens will require a proactive approach to
water treatment, including plant optimization.
2.3 Relationship Between Optimized
Performance and Public Health Protection
2.3. 7 Multiple Barrier Strategy
Microbial pathogens, including protozoan para-
sites, bacteria, and viruses, can be physically
removed as particles in flocculation, sedimenta-
tion, and filtration treatment processes or inacti-
vated in disinfection processes. Consequently, the
level of protection achieved in a water system can
be increased by optimizing the particle removal
processes in a system and by proper operation of
the disinfection processes. In a conventional
plant, the coagulation step is used to develop par-
ticles that can be physically removed by sedimen-
tation and filtration processes. Effective use of
these processes as part of a multiple barrier strat-
egy for microbial protection represents an opera-
tional approach for water systems that choose to
optimize performance. This strategy is also being
proposed as a method for addressing Cryptospo-
ridium in the Interim Enhanced Surface Water
Treatment Rule (10).
Particle removal through a water treatment proc-
ess can be monitored and assessed by various
methods including turbidity, particle counting, and
microscopic particulate analysis (MPA). An
increasing number of water systems treating a sur-
face water supply have turbidimeters installed to
monitor turbidity at various locations throughout
the process. Some systems are supplementing
turbidity monitoring with particle counting and
microscopic particulate analysis, However,
because turbidity monitoring is the most common
method of assessing particle removal in surface
water systems, performance goals based on this
parameter have been developed for the CCP to
define optimized system performance.
The role of multiple treatment barriers in optimiz-
ing water treatment for protection from microbial
pathogens and the associated performance goals
are shown in Figure 2-1. Despite variability in
source water quality, surface water treatment
plants must produce consistently high quality fin-
ished water. To meet this objective, each treat-
ment process must consistently produce treated
water of a specific quality. To this end,
-------
Figure 2-1. Multiple barrier strategy for microbial contaminant protection.
Coagulant
Addition
Variable
Quality
Flocculation/Sedimentation
Barrier
Filtration
Barrier
Disinfection
Barrier
performance goals have been established for each
of the treatment barriers in a plant.
When plants include a sedimentation process, the
maximum sedimentation basin effluent turbidity
goal of less than 2 NTU is used to define optimum
process performance. A sedimentation perform-
ance goal ensures the integrity of this barrier and
provides a consistent particle loading to the filtra-
tion process. With respect to optimum particle
removal for the filtration process, the optimum
performance goal is defined as achieving individual
filter effluent turbidities of less than 0.1 NTU.
The performance of the disinfection barrier is
based on the log inactivation requirement for Giar-
dia and virus, as established by the Surface Water
Treatment Rule guidance manual (11). This
document provides tables of the required CT (i.e.,
disinfectant concentration (C) times the time (T)
that the disinfectant must be in contact with the
water) to achieve different levels of inactivation
based on the temperature and pH of the water.
The amount of log inactivation, and hence the CT
value that the plant must achieve, is based on
SWTR guidance.
Inactivation requirements for Ctyptosporidium
based on CT have not been established but would
be significantly higher than those for Giardia and
virus. Since inactivation of Cryptosporidium is
difficult to achieve with chlorine disinfection,
maximizing particle removal could represent the
most cost effective and viable option for maximiz-
ing public health protection from this microorgan-
ism.
2.3.2 Basis for Optimization Goals
Strong evidence exists in support of maximizing
public health protection by optimizing particle
removal in a plant. Recent supportive evidence
from water treatment research and field evalua-
tions is summarized below:
• Pilot study work conducted by Patania (12)
showed that when treatment conditions were
optimized for turbidity and particle removal,
very effective removal of both Cryptosporidium
and Giardia was observed. Cryp tosporidium
removal ranged from 2.7 to 5.9 logs, and
Giardia removal ranged from 3.4 to 5.1 logs
during stable filter operation. Under the condi-
tions tested, meeting a filter effluent turbidity
goal of 0.1 NTU was indicative of treatment
performance producing the most effective cyst
and oocyst removal. A small difference in fil-
ter effluent turbidity (from 0.1 or less to
between 0.1 and 0.3 NTU} produced a large
difference (up to 1.0 log) in cyst and oocyst
removal.
• Pilot study and full-scale plant work performed
by Nieminski (13) demonstrated that consis-
tent removal rates of Giardia and Cryptospo-
ridium were achieved when the treatment plant
was producing water of consistently low tur-
bidity (0.1 - 0.2 NTU). As soon as the plant's
performance changed and water turbidity fluc-
tuated, a high variability in cyst concentration
was observed in collected effluent samples.
The pilot study work, confirmed by full-scale
plant studies, showed that in a properly
-------
operated treatment plant producing finished
water of 0.1 to 0.2 NTU, either conventional
treatment or direct filtration can achieve 3-log
removal of Giardia cysts.
• An extensive amount of water filtration
research was conducted at Colorado State
University on low turbidity water (14,151.
Using field-scale pilot filters, researchers dem-
onstrated greater than 2-log Giardia removal
when proper chemical coagulation was prac-
ticed on low turbidity raw water (i.e., 0.5 to
1.5 NTU), resulting in filter effluent turbidity
values of less than 0.1 NTU.
Filter plant performance evaluations conducted
by Consonery (16) at 284 Pennsylvania filtra-
tion plants over the past eight years have
included a combination of turbidity, particle
counting, and microscopic particulate analysis
to assess the performance of plant processes.
The person completing the evaluation uses this
information to rate the plant as to whether it
provides an acceptable level of treatment for
microbial pathogens. Evaluation results have
shown that when filter effluent turbidity was
less than or equal to 0.2 NTU, 60 percent of
the plants were given an acceptable rating.
When filter effluent turbidity was greater than
or equal to 0.3 NTU, only 11 percent of the
plants were given an acceptable rating.
Although this work did not assess plant per-
formance at the 0.1 NTU level, the increased
acceptable rating that occurred when effluent
turbidity was less than 0.2 NTU versus
0.3 NTU indicates the benefit of lowering
finished water turbidity.
An extensive amount of research and field work
results support a filtered water turbidity goal of
0.1 NTU. These findings are also compatible with
a long standing AWWA Policy Statement support-
ing treatment to this level (17). It is important to
understand that achieving this level of filter per-
formance (i.e., 0.1 NTU) does not guarantee that
microbial pathogens will not pass through filters;
however, it represents the current best practice for
water treatment plants to achieve the greatest
level of public health protection.
Particle counting can be used to support and
enhance turbidity measurements, and can be
especially useful when source water turbidity is
low (< 5 NTU). At low source water turbidity
levels, it is difficult to assess the level of particle
reduction being achieved in the filtration process
with turbidity measurements alone. This is due to
the insensitivity of turbidimeters at extremely low
turbidity measurements (i.e., below about
0.05 NTU) (18,19,20).
2.4 Optimization Performance Goals
For purposes of this handbook, optimized water
treatment performance for protection against
microbial pathogens is defined by specific meas-
urements and goals. This section presents the
performance goals for surface water treatment
systems. These goals are based on CCP field
work performed by the authors and experience
gained from the Partnership for Safe Water and
state optimization pilot programs. It is important
to note that these goals are the foundation for all
assessments in this handbook and that obtaining
this performance level exceeds present regulatory
requirements.
2.4.1 Minimum Data Monitoring
Requirements
• Daily raw water turbidity
• Settled water turbidity at 4-hour time incre-
ments from each sedimentation basin
• On-line (continuous) turbidity from each filter
• One filter backwash profile each month from
each filter
2.4.2 Individual Sedimentation Basin
Performance Goals
• Settled water turbidity less than 1 NTU
95 percent of the time when annual average
raw water turbidity is less than or equal to
10 NTU.
• Settled water turbidity less than 2 NTU
95 percent of the time when annual average
raw water turbidity is greater than 10 NTU.
2.4.3 Individual Filter Performance Goals
• Filtered water turbidity less than 0.1 NTU
95 percent of the time (excluding 15-minute
period following backwashes) based on the
10
-------
maximum values recorded during 4-hour time
increments.
If particle counters are available, maxi-
mum filtered water measurement of less
than 10 particles (in the 3 to 18 //m
range) per milliliter. (Note: The current
state-of-the-art regarding calibration of
particle counters and the inherent prob-
lems in comparisons of readings between
different counters must be considered in
using particle count information to assess
optimized performance. Higher readings
than the above 10 particles/ml goal from
a counter that is properly calibrated may
be a function of differences between
instruments. Relative changes in particle
count data will be of greater use in
assessing optimized performance than the
absolute values from the particle counter).
Maximum filtered water measurement of
0.3 NTU.
Initiate filter backwash immediately after tur-
bidity breakthrough has been observed and
before effluent turbidity exceeds 0.1 NTU.
Maximum filtered water turbidity following
backwash of less than 0.3 NTU.
Maximum backwash recovery period of
15 minutes (e.g., return to less than 0.1 NTU).
2.4.4 Disinfection Performance Goal
. ' CT values to achieve required log inactivation
of Giardia and virus.
2.5 Role of the Water Treatment Plant
Staff in Public Health Protection
The information presented in this chapter demon-
strates that the quality of water leaving a water
treatment plant has the potential to directly impact
the health of the consumers of its finished water.
All staff associated with the plant, from the opera-
tor to the highest level administrator, have an
important role in protecting public health and a
responsibility to provide finished water that mini-
mizes the possibility of a disease outbreak. Expe-
rience gained from implementing CCP optimization
activities at plants has demonstrated that, in most
situations, once utility staff become aware of the
importance of achieving optimized performance
goals, they have enthusiastically pursued these
goals through a variety of activities. Later chap-
ters present comprehensive procedures for
assessing and achieving the level of performance
described in this chapter.
2.6 References
1. Kramer, M.H., et al. 1996. "Waterborne Dis-
ease: 1993 and 1994." Journal A WWA,
88{3):66.
2. Chauret, C., et al. 1995. "Correlating Crypto-
sporidium and Giardia With Microbial Indica-
tors." JournalAWWA, 87(11):76.
3. LeChevallier, M.W., et al. 1995. "Giardia and
Ctyptosporidium in Raw and Finished Water."
Journal A WWA, 87(9):54.
4. States, S., et al. 1997. "Protozoa in River
Water: Sources, Occurrence, and Treatment. "
Journal A WWA, 89(9): 74.
5. Solo-Gabriele, H., et al. 1996. "U.S. Out-
breaks of Cryptosporidiosis. " Journal A WWA,
88(91:76.
6. Pett, B., et al. 1993. "Cryptosporidiosis Out-
break From an Operations Point of View:
Kitchener-Waterloo, Ontario." Paper presented
at AWWA Water Quality Technology Confer-
ence, Miami, FL.
7. Richardson, A.J., et al. "An Outbreak of
Waterborne Cryptosporidiosis in Swindon and
Oxfordshire." Epidemiol. Infect, 107(3)485.
8. Korich, D.G., et al. 1990. "Effects of Ozone,
Chlorine Dioxide, Chlorine, and Monochlora-
m i n e on Cryptosporidium parvum O o c y s t
Viability." Applied and Environmental Microbi-
ology, 56(5):1423.
9. Finch, G.R., et al. 1995. "Ozone and Chlorine
Inactivation of Cryptosporidium. " In Proceed-
ings of Water Quality Technoloov Conference.
November 6-10. 1994. San Francisco. CA.
AWWA, Denver, CO.
10. USEPA. 1997. National Primary Drinking
Water Regulations: Interim Enhanced Surface
Water Treatment Rule; Notice of Data
11
-------
Availability; Proposed Rule. Fed.
62:212:59486 (November 3, 1997).
Reg.,
11. Guidance Manual for Compliance With the
Filtration and Disinfection Reauirements for
Public Water Systems Usina Surface Water
Sources. 1989. NTIS No. PB-90148016,
USEPA, Cincinnati, OH.
12. Patania, N.L., et al. 1996. Ootimization of
Filtration for Cvst Removal. AWWARF,
Denver, CO.
13. Nieminski, E.G., et al. 1995. "Removing
Giardia and Cryptosporidium by Conventional
Treatment and Direct Filtration." Journal
AWWA, 87(9):96.
14. Mosher, R.R., et al. 1986. "Rapid Rate Filtra-
tion of Low Turbidity Water Using Field-Scale
Pilot Filters." Journal AWWA, 78(3) :42.
15. AI-Ani, M.Y., et al. 1986. "Removing Giardia
Cysts From Low Turbidity Water by Rapid
Sand Filtration." Journal A WWA, 78(5):66.
16. Consonery, P.J., et al. 1996. "Evaluating and
Optimizing Surface Water Treatment Plants:
How Good is Good Enough?" Paper presented
at AWWA Water Quality Technology Confer-
ence, November 1996, Boston, MA.
17. AWWA Statement of Policy. 1968. Quality
Goals for Potable Water, Journal AWWA,
60(12):1317.
18. Cleasby, J.L., et al. 1989. Design and Opera-
tion Guidelines for Optimization of the High
Rate Filtration Process: Plant Survey Results.
AWWARF, Denver, CO.
19. West, T., P. Demeduk, G. Williams, J.
Labonte, A. DeGraca, and S. Teefy. 1997.
"Using Particle Counting to Effectively Monitor
and Optimize Treatment." Paper presented at
AWWA Annual Conference, Atlanta, Georgia.
20. Veal, C., and B. Riebow. 1994. "Particle
Monitor Measures Filter Performance."
Opflow, 20(5): 1.
12
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Chapter 3
Assessing Composite Correction Program A pplica tion
3.1 Introduction
The CCP is currently used as an optimization tool
by several EPA regional offices and state drinking
water programs, and its use could increase as the
result of possible new turbidity requirements when
the Interim Enhanced Surface Water Treatment
Rule (IESWTR) is promulgated (1). However, the
most effective application of the approach has not
always been achieved. Results from CCP field
experience and state pilot programs have indicated
that the CCP is most effective when it is strategi-
cally integrated into a program that focuses on
area-wide optimization of water treatment sys-
tems. This chapter describes a developing pro-
gram for regulatory agencies and others to initiate
effective CCP-based optimization activities through
the implementation of an area-wide optimization
model.
3.2 Optimization Program Experience
The experience gained from the transfer of CCP
capability to state drinking water programs is dis-
cussed in Chapter 1, These activities provided
valuable insights into the use of the CCP as an
optimization tool by primacy agencies. The objec-
tive of the early pilot programs was to demon-
strate the capability to effectively transfer CCP
skills to state personnel and to facilitate state-wide
implementation of these activities. Several chal-
lenges became apparent during the implementation
phase. The CCP approach, while considered
extremely valuable, was also considered to be
resource intensive and, therefore, in competition
with other state program activities. In some
states with decentralized programs, field and cen-
tral office personnel had difficulty defining their
roles and responsibilities for implementing optimi-
zation activities. Primacy agency policies guiding
the implementation of follow-up efforts were
sometimes challenged (e.g., enforcement versus
assistance responsibilities). As the state pilot pro-
grams progressed, these challenges to implemen-
tation became known collectively as institutional
barriers. In some cases these institutional barriers
were pervasive enough to prevent state teams
trained in CCP procedures from using their new
technical skills at plants with potential public
health concerns.
Despite the identified institutional barriers, the
continued success of the CCP efforts at individual
facilities could not be ignored (2). In addition,
experience gained from the broad-scale implemen-
tation of the CCP through state optimization pilot
programs and the Partnership for Safe Water dem-
onstrated that improvement in water treatment
performance could be achieved through multiple
activities that are based on CCP concepts. Some
specific examples include:
• Self-Assessment Based on CCP Can Positively
Impact Performance: Activities that involve
water utilities with the development and inter-
pretation of their turbidity data have provided
utility staff with a different perspective on
assessing their performance and have resulted
in utility-directed changes to their operation
and system that have improved performance.
Specifically, many water utilities that have par-
ticipated in the Partnership for Safe Water
have acknowledged that associated turbidity
data trending activities have focused them on
improving their plant performance to achieve
the Partnership goals (3).
• Centralized Trainina Usina CCP Principles Can
Impact Multiple Facilities: The application of
CCP-based principles through centralized,
facilitated training workshops represents an
effective and efficient approach to assist a
group of utilities with achieving optimization
goals. Specifically, a training facilitator in
Pennsylvania, working with a group of water
utilities, used CCP-based process control pro-
cedures in a workshop format to improve
coagulant dosing understanding and applica-
tion (41.
• CCP Components Can be Used to Enhance
Existina State Proaram Activities: Aligning
existing programs (e.g., sanitary surveys,
facility outreach) with the CCP approach can
enhance achievement of performance goals.
For example, existing state sanitary survey
13
-------
programs in Texas and Pennsylvania were
modified to include performance-related CPE
activities (e.g., individual filter evaluations, fil-
ter backwash special studies, process control
interviews) (5).
These findings supported a strategic change in the
CCP direction. The result was an organizational
framework for implementing optimization activities
on an area-wide basis.
3.3 Area-Wide Optimization Model
An area-wide optimization model was developed
that creates an environment to effectively apply
existing resources (e.g., state programs and per-
sonnel) with proven performance improvement
tools (e.g., CCP). Major components of the cur-
rent model include: Status, Evaluation, Follow-Up
and Maintenance. These components are des-
cribed in Figure 3-1. This model represents a pro-
active approach to public health protection,
serving to promote continuous improvement and
addressing performance-related issues when they
first become apparent. Pervasive throughout the
area-wide optimization program is an awareness
building process linking treatment plant perform-
ance with public health protection. It is important
to note that an area-wide optimization program is
an ongoing activity with an overall objective to
improve the performance level of all water sys-
tems.
Future activities are planned to enhance the area-
wide optimization model. Potential activities
include expanded optimization efforts at surface
water treatment facilities (e.g., disinfection by-
products, source water protection, distribution
system water quality), and optimization activities
related to ground water systems.
3.3. / Status Component
Status Component activities are designed to deter-
mine the status of water systems relative to opti-
mized performance goals within a defined area
(e.g., state, region, district). Implementers of
optimization programs then use the results of
these activities in a prioritization process to con-
tinuously focus available resources where they are
most needed, typically at high risk public health
systems. A key activity under the Status Compo-
nent is continuous performance monitoring, which
can be used to effectively measure the success of
the various optimization efforts associated with
the model.
3.3.2 Evaluation Component
Evaluation Component activities focus on the
determination of factors limiting performance for
those water systems where performance problems
were identified from Status Component activities.
Existing evaluation programs can be utilized by
incorporating performance-focused activities. The
most resource-intensive evaluation tools, such as
CPEs, are applied at water systems presenting the
greatest risk to public health.
3.3.3 Folio w-Up Component
Follow-Up Component activities focus on identify-
ing and developing technical assistance method-
ologies, such as the CTA, to systematically
address performance limiting factors at these sys-
tems. Coordination and training of available tech-
nical resources (e.g., state drinking water program
trainers, non-profit organizations, water system
peers, consultants) are important activities to
assure consistency and effectiveness of this com-
ponent. The degree of involvement of regulatory
agency personnel in follow-up activities may be
impacted by the agency's policies on enforcement
versus technical assistance. In these situations,
policies should be clearly established and agreed
upon by agency staff prior to implementing follow-
up activities.
3.3.4 Maintenance Component
The Maintenance Component formalizes a feed-
back loop to integrate the "lessons learned" from
the various component activities back into the
model. In addition, these "lessons learned" can
provide opportunities to coordinate findings with
other related programs.
3.4 Implementation of an Area-Wide
Model
Figure 3-2 shows the status of filtration plant tur-
bidity performance during a two-year period when
a state was initiating an area-wide optimization
program <5). For those plants that achieved
improved performance levels, this progress was
accomplished through their participation in Status
14
-------
Component activities such as turbidity monitoring
and Follow-Up Component activities such as
chemical feed training. This figure demonstrates
some of the benefits of using the Status Compo-
nent to continuously monitor the water system's
level of performance relative to the desired per-
formance goal. For example, systems representing
the greatest public health risk are apparent. In
addition, systems showing improved performance
can be assessed to ascertain the reasons for such
improvement. In some cases, an awareness of the
importance of optimized performance by the water
system has been identified as a major contributing
factor for the change.
Figure 3-1. Area-wide optimization model.
9
9
9
9
9
STATUS COMPONENT
Establish optimized performance goals.
Routinely prioritize water systems based on public health risk.
Continuously monitor and assess performance data.
Incorporate performance-based activities into existing surveillance
programs.
Establish feedback mechanism to include monitoring and surveillance data
into ongoing prioritization process.
i
9
9
9
9
EVALUATION COMPONENT
Focus existing programs on optimized performance goals.
Use CCP-based evaluations to identify factors limiting performance.
Implement CPEs at high risk systems.
Identify and develop resources to provide CCP-based evaluations.
4
9
9
9
9
FOLLOW-UP COMPONENT
Establish parties responsible for follow-up component activities.
Utilize a follow-up protocol that systematically addresses factors limiting
performance.
Identify and develop resources to provide CCP-based follow-up activities.
Coordinate existing programs to complement performance improvement
efforts.
*
9
9
MAINTENANCE COMPONENT
Integrate optimization efforts with other drinking water program activities,
such as design review, training, and funding.
Identify and implement ongoing optimization program refinements.
15
-------
Figure 3-2. Area-wide treatment plant performance status.
= 70
^
d
60
|
5 *n J
| 50
I
0 J
01996 11997
Ell
•
12345
rl
6 7 B 9 10 11 12 13
System
-
-
14 15
In the following sections, the Status Component is
further defined to provide a systematic procedure
for assessing applicability of the CCP. The four
steps of the procedure are: 11 establish perform-
ance focused goals to prioritize water systems,
2) assess performance relative to defined optimiza-
tion goals, 3) prioritize water systems based on
selected criteria, and 4) assess the response to the
prioritized water systems.
3.4.1 Establish Criteria to Prioritize Water
Systems
The initial step in the development of a prioritized
facility database is the selection of performance
focused criteria. Example prioritization criteria for
surface water treatment systems are shown in
Table 3-1. In this example, criteria were selected
based on specific performance goals (e.g., tur-
bidity) and operations and management practices
that support optimized performance (e.g., process
control, staffing level).
Points are applied to each criterion relative to their
potential to impact public health risk. For exam-
ple, the ability to meet the filtered water turbidity
goal of 0.1 NTU is given a higher number of points
as the percentage of time meeting this goal
decreases. Additional data required to complete
the assessment outlined in Table 3-I can usually
be obtained from existing resources (e.g., plant
performance charts, water system monthly
reports, sanitary surveys). It may be necessary to
expand the data collection requirements from
water systems to assure that sufficient perform-
ance focused information is available for this
activity.
3.4.2 Assess Water System Performance
Relative to Optimization Goals
Typically, each water system utilizing a surface
water source collects and records plant perform-
ance data on a daily basis. These data can be
entered into a computer by either water system
staff, regulators, or others on a monthly basis
using a spreadsheet program such as the Partner-
ship lor Safe Wafer software included in
Appendix A. Data are then used to develop
turbidity trend charts and percentile tables.
Specific types of turbidity data included in the
assessment are listed below.
16
-------
. Raw water turbidity (daily value; maximum
value recorded for the day preferred).
. Sedimentation basin effluent turbidity (daily;
maximum value recorded for the day pre-
ferred).
. Filter effluent turbidity (daily for each filter;
maximum value preferred; combined filter or
finished water as alternative).
A minimum of 12 months of turbidity data is
desired to assess water system performance under
variable source water conditions. An example tur-
bidity monitoring chart for a surface water treat-
ment system is shown in Figure 3-3. Raw,
settled, and filtered water turbidity values are
plotted for a 12-month period. In this example,
overall filtered water quality is excellent; however,
occasional turbidity spikes occur in the filtered
water that correspond to increases in the raw
water turbidity.
3.4.3 Prioritize Water Systems Based on
Selected Criteria
When prioritization criteria data are available for
the water systems that are to be included in the
area-wide optimization program, each of the sys-
tems can be assigned points, as shown in Ta-
ble 3-2. The water systems are then ranked from
highest priority (i.e., most points) to lowest pri-
ority (i.e., least points). Ideally, a prioritized water
Table 3-1. Example Prioritization Criteria for Surface Water Systems
Prioritization Criteria
Has the water system had an imminent health violation within the last two (2)
years (turbidity, CT, positive coliform)?
Does the water system achieve the optimization turbidity goal for filtered water of
0.1 NTU?
>_ 95 % time
50 - < 95 % time
< 50 % time
Does the water system experience post filter backwash turbidity of > 0.3 NTU
for greater than 15 minutes?
Does the water system achieve the optimization turbidity goal for settled water
(e.g., < 2 NTU 95% time)?
Does the water system have operation and treatment problems (e.g., improper
chemical feed, improper jar testing, inadequate procedures)?
Does the water system experience sedimentation and filtered water turbidity
variability given changing raw water quality?
Does the water system lack administrative support (e.g., inadequate funding,
inadequate support of system operational needs)?
Does the water system have poor source water quality (e.g., high turbidity vari-
ability, high presence of protozoan parasites)?
Does consistent, high-quality source water lead to complacency in the operation
and management of the water system?
Does the water system fail to monitor raw, settled and filtered water turbidity?
Points
(0 if No)
10 - 15
0
5
10
O-l 0
o - 5
o - 5
O - 5
o - 5
o - 3
0-3
o - 3
17
-------
Figure 3-3. Example turbidity monitoring data for 12-month period.
1000
100-
95 % time settled turbidity <9 7 Nil!
95 % time filtered turbidity < 0.1 NTU
I
1-
1/1/95 2/1/95 3/4/95 4/4/95 5/5/95 6/5/95 7/6/95 8/6/95 9/6/95 10/7/95 11/7/95 12/8/95
Taible 3-2. Example Prioritization Database
Water
System
2
1
5
3
7
6
10
9
6
4
Violations
12
15
10
10
0
0
0
0
0
0
Filter
Turbidity
Performance
5
10
5
5
2
2
2
0
2
0
Settled
Turbidity
Performance
5
3
3
3
3
2
4
3
3
2
O&M
Problems
5
5
3
5
2
3
3
3
1
0
Variability
5
3
3
3
3
3
3
2
3
0
Backwash
Spikes
5
5
4
3
4
2
3
0
0
0
Admin
Support
5
2
2
0
3
4
S
4
2
2
Poor
Source
Water
0
0
2
0
2
0
0
3
3
0
Complacency
& Reliability
3
0
0
0
4
4
0
4
0
0
Lack of
Monitoring
3
3
3
3
4
5
3
0
0
0
Total
Points
46
46
35
32
27
25
23
19
14
4
system database would include each system and
their total point score. This database should be
updated routinely (e.g., quarterly) to reflect new
information from system reports, field surveys,
and performance data.
3.4.4 Assess Response to Prioritized Water
Systems
Information gained from the prioritization database
provides the basis for determining the appropriate
response to achieving performance .goals. For ex-
ample, some specific actions that could result from
an area-wide prioritization database include:
. High scoring utilities:
• Apply CCP
Modifications/major construction
• Enforcement action
18
-------
. Moderate scoring utilities:
Performance-focused sanitary survey
• Centralized training using CCP principles
(focus on high ranking performance limit-
ing factors)
• Low scoring utilities:
. Telephone contact
• Self-assessment
Maintain or reduce frequency of sanitary
surveys
Use of a performance-based prioritization database
provides assurance that the identified responses
are commensurate with the level of public health
risk. Following this approach, the CCP, a proven
process that can result in optimized performance,
is applied at water systems that have the highest
public health risk.
3.5 References
1 . USEPA. 1997. National Primary Drinking
Water Regulations: Interim Enhanced Surface
Water Treatment Rule; Notice of Data Avail-
ability; Proposed Rule. Fed. Reg.,
62:212:59486 (November 3, 1997).
2. Renner, R.C., B.A. Hegg, J.H. Bender, and
E.M. Bissonette. 1993. "Composite Correc-
tion Program Optimizes Performance at Water
Plants." JournalAWWA, 85(3):67.
3. Pizzi, N.G., B.A. Hegg, J.H. Bender, and
J. DeBoer. 1997. "Cleveland's Self-
Assessment and Contribution to the
Partnership for Safe Water Peer Review
Process." Proceedings - AWWA Annual
Conference. June 1997, Atlanta, GA.
4. Jesperson, K. 1997. "Pilot Program Ripples
Through PA DEP." E-Train, Published by the
National Environmental Training Center for
Small Communities.
5. Hoover, J.T., R.J. Lieberman, L.D. DeMers,
and J. Borland. 1997. "Public Water Supply
Area-Wide Optimization Strategy." Presenta-
tion at the Association of State Drinking Water
Administrators Annual Conference, October
1997, Savannah, GA.
19
-------
Chapter 4
Comprehensive Performance Evaluation
4,1 Introduction
This chapter provides information on the evalua-
tion phase of the CCP, which is a two-step proc-
ess to optimize the performance of existing sur-
face water treatment plants. For purposes of this
handbook, optimization is defined as achieving the
performance goals as outlined in Chapter 2. The
evaluation phase, called a Comprehensive Perform-
ance Evaluation (CPE), is a thorough review and
analysis of a facility's design capabilities and
associated administrative, operational, and main-
tenance practices as they relate to achieving opti-
mum performance from the facility. A primary
objective is to determine if significant improve-
ments in treatment performance can be achieved
without major capital expenditures. This chapter
covers three main areas related to CPEs. First, a
CPE methodology section presents all of the major
technical components of a CPE and their theoreti-
cal basis. The following section discusses how to
implement the CPE methodology when conducting
a CPE. This section also includes many practical
considerations based on the field experience
gained by conducting actual CPEs. The last sec-
tion of this chapter includes a case history of an
actual CPE.
4.2 CPE Methodology
Major components of the CPE process include;
1) assessment of plant performance, 2} evaluation
of major unit processes, 3) identification and pri-
oritization of performance limiting factors,
4} assessment of applicability of the follow-up
phase, and 5} reporting results of the evaluation.
Although these are distinct components, some are
conducted concurrently with others during the
conduct of an actual CPE. A discussion of each of
these components follows.
4.2, / Assessment of Plant Performance
The performance assessment uses historical data
from plant records supplemented by data collected
during the CPE to determine the status of a facility
relative to achieving the optimized performance
goals, and it starts to identify possible causes of
less-than-optimized performance. To achieve
optimized performance, a water treatment plant
must demonstrate that it can take a raw water
source of variable quality and produce a consistent
high quality finished water. Further, the perform-
ance of each unit process must demonstrate its
capability to act as a barrier to the passage of par-
ticles at all times. The performance assessment
determines if major unit treatment processes con-
sistently perform at optimum levels to provide
maximum multiple barrier protection. If perform-
ance is not optimized, it also provides valuable
insights into possible causes of the performance
problems and serves as the basis for other CPE
findings.
4.2.1.1 Review and Trend Charting of Plant
Operating Records
The performance assessment is based on turbidity
data located in plant operating records, These
records, along with a review of laboratory quality
control procedures (especially calibration of turbi-
dimeters) and sample locations, are first assessed
to ensure that proper sampling and analysis have
provided data that is representative of plant per-
formance. The next step is to prepare trend
graphs of the maximum daily turbidities for the
raw water, settled water, finished water, and indi-
vidual filter effluents, if available. Data for the
most recent one-year period is used in this evalua-
tion and can typically be obtained from the plant's
process control data sheets. Maximum values are
used in these trend charts since the goal is to
assess the integrity of each barrier at its most vul-
nerable time. A twelve-month period is utilized
because it includes the impacts of seasonal varia-
tions and provides a good indicator of long term
performance.
Data development can be accomplished by using a
commercial computer spreadsheet. However,
spreadsheets that work with several commercially
available spreadsheet programs were developed
for the Partnership for Safe Water (1) and have
proven valuable in making the desired performance
assessment trend charts. The Partnership data
development spreadsheets and a description of
how to use them are provided in Appendix A.
21
-------
Figure 4-1 shows an example of performance
assessment trend charts prepared for a typical
plant. In addition to the trend charts, a percentile
analysis can also be made using the data to
determine the percent of time that raw, settled
and finished water quality is equal to or less than a
certain turbidity. This information can be used to
assess the variability of raw water turbidity and
the performance of sedimentation and filtration
unit processes. The percentile analysis of settled
and finished water quality are useful to project a
plant's capability to achieve optimized perform-
ance objectives. An example of the percentile
analysis for the data shown in Figure 4-1 is pre-
sented in Table 4-I. It is noted that the trend
charts and the percentile analysis are developed as
a portion of the Partnership data development
spreadsheets and are shown in Appendix A. The
data provided in Table 4-I was taken from the
yearly summary on the percentile portion of the
software output. It is often useful to summarize
the data in this fashion since the spreadsheet pro-
vides a significant amount of information.
Once the trend charts and percentile analysis have
been developed, interpretation of the data can be
accomplished. A good indication of the stability of
plant operation can be obtained from comparing a
plot of raw water, settled water and finished water
turbidity. When comparing these data, the evalua-
tor should look for consistent settled and filtered
water turbidities even though raw water quality
may vary significantly. In Figure 4-I the raw
water turbidity shows variability and several sig-
nificant spikes. Variability is also evident in the
settled and finished water turbidities. In addition a
raw water "spike" on March 9th carried through
the plant resulting in a finished water turbidity
close to 1 NTU. These "pass through variations
and spikes" indicate that the performance of this
plant is not optimized and that a threat of particle
and possibly pathogen passage exists. In plants
that have consistent low raw water turbidities,
periodic spikes in sedimentation and finished water
that appear related to changes in raw water quality
may indicate that the plant staff are complacent
and lack process control skills. The administrative
support for the plant may also play a role in this
complacency.
Optimized performance for the sedimentation basin
in the example is assessed based on achieving set-
tled water turbidities consistently less than 2 NTU
in 95 percent of the samples, since the average
raw water turbidity exceeds 10 NTU (e.g.,
19 NTU). In the example shown, the settled
water turbidity was less than or equal to 5.3 NTU
at the 95th percentile. This indicates less-than-
optimum performance from this process barrier.
Optimized performance for the finished water is
assessed based on achieving 0.1 NTU or less in
95 percent of the samples. For the example
shown, the finished water was 0.48 NTU or less
in 95 percent of the samples; consequently, opti-
mum performance was not being achieved by this
barrier. In summary, the interpretation of the data
shown in Figure 4-I and Table 4-I indicates that
optimum performance is not being achieved, and it
will be necessary to identify the causes for this
less-than-optimum performance during the conduct
of the CPE.
CPEs conducted to date have revealed that oper-
ating records often do not have adequate informa-
tion to complete the performance assessment.
Maximum daily turbidities are often not recorded
and settled water turbidity information often does
not exist. The fact that this type of information is
not available provides a preliminary indication
about the priority that the utility has on pursuing
achievement of optimum performance goals.
Particle data, when available, can also be used to
assess optimized performance. Typically, particle
data will provide a more sensitive assessment of
filter performance when the turbidity is less than
0.1 NTU. Particle counts will normally show more
subtle changes in filter performance than indicated
by the turbidimeters. This does not mean that
turbidimeter information should be ignored when
particle count data is available. It is important that
the evaluator have confidence in the filter's per-
formance relative to producing water that is less
than 0.1 NTU.
4.2.1.2 Supplemental Data Collection
Plant records used for the trend charting perform-
ance assessment activities are usually based on
clean/veil samples collected at four-hour intervals
as required by regulations. Complete assessment
of optimized performance, however, also requires
knowledge of the instantaneous performance of
individual treatment units; especially for individual
filters. Many plants currently do not have separate
turbidimeters on individual treatment units, and
most of these do not have equipment that will
provide continuous recording of the data. To sup-
plement the performance data available from the
22
-------
Figure 4-1. Example performance assessment trend charts.
Raw Wats:
120.00
100.00
2
I-
Z 80.00
>•
2 60.00
JD
fe
a
*- 40.00
20.00
0.00
Example of Pass Through
Ev«nt on 3/9/98
25.00
20.00
— 1 5.00 --
10.00 --
i.OO --
0.00
g
I-
0.00
Settled Water
Finished W ater
23
-------
Table 4-1. Percentile Distribution Analysis of
Water Quality Date*
Percent of Time
Values
Less Than or
Equal To
Value Shown
50
75
90
95
Average
Raw
Water
Turbidity
NTU
17
22
29
34
19
Settled
Water
Turbidity
NTU
2.1
3.0
4.1
5.3
2.6
Finished
Water
Turbidity
NTU
0.30
0.38
0.44
0.48
0.31
'Percentile analysis is based on peak daily turbiditias measured
for each sample source for the twelve-month evaluation period.
plant records, additional turbidity performance
data is usually collected during the CPE.
Optimum performance cannot be assessed without
an evaluation of individual filter performance. Fin-
ished water samples are often obtained from the
clean/veil. The clean/veil "averages" the perform-
ance of the individual filters and thus may mask
the impact of damaged underdrains, of "blown
media" on an individual filter, or of malfunctioning
filter rate control valves. A malfunctioning indi-
vidual filter could allow the passage of sufficient
microbial contamination to threaten public health
despite the plant as a whole producing a low fin-
ished water turbidity. A second reason for the
need of supplemental data collection is that most
plants do not keep records of their filter backwash
recovery profiles. These are needed to assess if
the plant is meeting the filter backwash recovery
optimized performance goals.
Since this instantaneous individual filter perform-
ance data is so critical, it is usually best if one or
two independently calibrated on-line continuous
recording turbidimeters are available during the
CPE. Along with providing the ability to assess
the performance of individual filters, these units
also allow a quality control check on the plant's
monitoring equipment. On-line units will provide
more information on the impacts of various
operational changes such as filter backwashes and
changes in flow rates. Grab sampling from indi-
vidual filters can provide useful insights about the
performance of individual filter units, but a con-
tinuous recording turbidimeter provides more accu-
rate results. Grab sampling to assess individual
filter performance is also cumbersome because
many samples at short time increments (e.g.,
1 minute intervals) are needed to get an accurate
filter backwash recovery profile. It is noted, how-
ever, that in a plant with multiple filters it is
advantageous to collect grab samples from indi-
vidual filters for turbidity analysis before selecting
the filter that is to be monitored by the continuous
recording turbidimeter. The filter demonstrating
the poorest performance should be selected for
analysis. If all filters demonstrate similar perform-
ance, it is desirable to install the on-line turbidime-
ter on a filter to be backwashed to allow observa-
tion of the backwash recovery profile.
Continuous monitoring and recording of turbidity
from each filter allows identification of short term
turbidity excursions such as: impacts of malfunc-
tioning filter rate control valves, impacts of hy-
draulic changes such as adjustments to plant flow,
impacts of hydraulic loading changes during
backwash of other filters, impacts of plant start-
up, and impacts of backwashing on individual fil-
ters. When the plant staff can properly apply
process control concepts they can eliminate these
variations in turbidity either through proper control
of the hydraulic loadings to the treatment proc-
esses or through chemical conditioning. These
types of turbidity fluctuations on the filter tur-
bidimeters are often indicators of inadequate proc-
ess control that must be verified during the CPE.
Figure 4-2 shows results of continuous recording
of turbidity from a filter that was backwashed. As
indicated, optimized performance of 0.1 NTU or
less was not being achieved prior to the back-
wash. Also, the post backwash turbidity spike of
0.95 NTU exceeded the optimized performance
goal of 0.3 NTU, and the filtered water turbidity
did not recover to 0.1 NTU or less within a 15-
minute period.
These same goals are also used to assess back-
wash spikes and optimized performance at plants
that use filter-to-waste. The 15-minute recovery
period starts when the filter begins filtering after
backwash even though the plant may filter-to-
waste for longer periods of time. The rationale for
24
-------
Figure 4-2. Example of individual filter monitoring.
0.90
0.80
0.70
3 0.60
I-
£°-5°
V
•£ 0.40
3
0.30
0.20
0.10
Resume Filtration
Begin Backwash
\
Plant Flow Reduced - Limited Chlorine Available
6 8 10 12 14 16 18 20
Time From Start of Continuous Filter Monitoring - hrs
22
24
this approach is that the control of backwash
spikes is a key indicator of the adequacy of the
plant's process control program and chemical con-
ditioning of the filters. Waiting until the filter-to-
waste is completed to assess backwash spikes
could hide key information relative to the process
control capability of the plant staff.
As discussed above, many plants do not collect
and/or record data on sedimentation basin per-
formance. During a CPE, therefore, it may be
necessary to collect sedimentation basin perform-
ance data to assess if this process is meeting the
optimized performance goals. It may be necessary
to collect data on individual sedimentation units if
one appears to have worse performance than the
others. Usually, grab sampling of these units will
suffice.
4.2.2 Evaluation of Major Unit Processes
4.2.2.1 Overview
The major unit process evaluation is an assess-
ment of treatment potential, from the perspective
of capability of existing treatment processes to
achieve optimized performance levels. If the
evaluation indicates that the major unit processes
are of adequate size, then the opportunity to opti-
mize the performance of existing facilities by ad-
dressing operational, maintenance or administra-
tive limitations is available. If, on the other hand,
the evaluation shows that major unit processes are
too small, utility owners should consider construc-
tion of new or additional processes as the initial
focus for pursuing optimized performance.
It is important to understand that the major unit
process evaluation only considers if the existing
treatment processes are of adequate size to treat
current peak instantaneous operating flows and to
meet the optimized performance levels. The intent
is to assess if existing facilities in terms of con-
crete and steel are adequate and does not include
the adequacy or condition of existing mechanical
equipment. The assumption here is that if the
concrete and steel are not of adequate size then
major construction may be warranted, and the
pursuit of purely operational approaches to achieve
optimized performance may not be prudent. The
condition of the mechanical equipment around the
treatment processes is an important issue, but in
this part of the CPE it is assumed that the poten-
tial exists to repair and/or replace this equipment
without the disruption of the plant inherent to a
major construction project. These types of issues
are handled in the factors limiting performance
component of the CPE, discussed later in this
chapter. It is also projected in the major unit
25
-------
process evaluation that the process control
requirements to meet optimized performance goals
are being met. By assuming that the equipment
limitations can be addressed and that operational
practices are optimized, the evaluator can project
the performance potential or capability of a unit
process to achieve optimized performance goals.
The evaluation approach uses a rating system that
allows the evaluator to project the adequacy of
each major treatment process and the overall plant
as either Type 1, 2 or 3, as graphically illustrated
in Figure 4-3. Type 1 plants are those where the
evaluation shows that existing unit process size
should not cause performance difficulties. In
these cases, existing performance problems are
likely related to plant operation, maintenance, or
administration. Plants categorized as Type 1 are
projected to most likely achieve optimized per-
formance through implementation of non-construc-
tion-oriented follow-up assistance (e.g., a CTA as
described in Chapter 5).
Figure 4-3. Major unit process evaluation
approach.
Plant Administrators or
Regulators Recognize Need to
Evaluate or Improve Plant
Performance
Evaluation of
Major Unit Processes
1
Type 1
Major Unit Processes
Are Adequate
*
Type 2
Major Unit Processes
Are Marginal
Type 3
Major Unit Processes
Are Inadequate
The Type 2 category is used to represent a situa-
tion where marginal capability of unit processes
could potentially limit a plant from achieving an
optimum performance level. Type 2 facilities have
marginal capability, but often these deficiencies
can be "operated around" and major construction
is not required. In these situations, improved pro-
cess control or elimination of other factors through
implementation of a CTA may allow the unit proc-
ess to meet performance goals.
Type 3 plants are those in which major unit proc-
esses are projected to be inadequate to provide
required capability for the existing plant flows.
For Type 3 facilities, major modifications are
believed to be required to achieve optimized per-
formance goals. Although other limiting factors
may exist, such as the operator's lack of process
control capability or the administration's unfamili-
ar ity with plant needs, consistent acceptable per-
formance cannot be expected to be achieved until
physical limitations of major unit processes are
corrected.
Owners with a Type 3 plant are probably looking
at significant expenditures to modify existing facili-
ties so they can meet optimized performance
goals. Depending on future water demands, they
may choose to conduct a more detailed engineer-
ing study of treatment alternatives, rate struc-
tures, and financing mechanisms. CPEs that iden-
tify Type 3 facilities are still of benefit to plant
administrators in that the need for construction is
clearly defined. Additionally, the CPE provides an
understanding of the capabilities and weaknesses
of all existing unit processes, operation and main-
tenance practices, and administrative policies.
As discussed in Chapter 2, water suppliers have a
key role to play in public health protection and a
responsibility to water quality that they must meet
on a continuous basis. If a facility is found to
pose a severe health risk because of its perform-
ance, some action must be taken even if it is
found to be Type 3. In the short term, other
weaknesses in the plant that are identified in other
components of the CPE may need to be addressed
to improve performance as much as possible. If
these actions do not result in satisfactory perform-
ance, a boil water order or water restriction may
have to be implemented until modifications are
completed and performance is improved. This may
require coordination with appropriate state regula-
tory agencies. The water system must also make
long term plans to upgrade or replace deficient
treatment processes.
Another situation that must be considered in com-
pleting the major unit process evaluation is the age
and condition of the plant. Though the CCP
approach attempts to minimize construction of
new facilities, some plants are so old that they are
not structurally sound and/or contain antiquated
equipment (e.g., outdated filter rate-of-flow control
valves). It is possible that the major unit process
evaluation will show these plants as Type 1
because they were designed based on conserva-
tive loadings and/or the water demand of the area
has not increased. In these cases, the owner of
the plant will have to look at the plant needs, both
long term and short term. In addition, the plant
26
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may be able to optimize performance to meet
short term public health protection, but will also
have to consider construction of a new plant in
order to provide high quality water on a long term
basis.
4.2.2.2 Approach
Major unit processes are evaluated based on their
capability to handle current peak instantaneous
flow requirements. The major unit processes
included in the evaluation are flocculation, sedi-
mentation, filtration and disinfection. These proc-
esses were selected for evaluation based on the
concept of determining if the basin sizes are ade-
quate. The performance potential of a major unit
process is not lowered if "minor modifications",
such as providing chemical feeders or installing
baffles, could be accomplished by the utility. This
approach is consistent with the CPE intent of
assessing adequacy of existing facilities to deter-
mine the potential of non-construction alternatives.
Other design-related components of the plant pro-
cesses, such as rapid mix facilities, are not
included in the major unit process evaluation but
rather are evaluated separately as factors that may
be limiting performance. For purposes of the
major unit process evaluation, these components
are projected to be addressed through "minor
modifications. " It is important to note that the
maior unit process evaluation should not be
viewed as a comparison to the original desian
caoabilitv of a olant. The maior unit Process
evaluation is based on an assessment of existing
unit processes to meet optimized performance
goals. These goals are most likely not the goals
that the existing facility was designed to achieve.
A performance potential graph is used to evaluate
major unit processes. As an initial step in the
development of the performance potential graph,
the CPE evaluators are required to use their judg-
ment to select loading rates which will serve as
the basis to project peak treatment capability for
each of the major unit processes. It is important
to note that the projected capability ratings are
based on achieving optimum performance from
flocculation, sedimentation, filtration and disinfec-
tion such that each process maintains its integrity
as a "barrier" to achieve microbial protection. This
allows the total plant to provide a "multiple bar-
rier" to the passage of pathogenic organisms into
the distribution system.
The projected unit process treatment capability is
then compared to the peak instantaneous operat-
ing flow rate experienced by the water treatment
plant during the most recent twelve months of
operation. If the most recent twelve months is not
indicative of typical plant flow rates, the evaluator
may choose to review a time period considered to
be more representative. The peak instantaneous
operating flow is utilized because unit process per-
formance is projected to be most challenged dur-
ing these peak loading events and it is necessary
that high quality finished water be produced on a
continuous basis.
An example performance potential graph is shown
in Figure 4-4. The major unit processes evaluated
are shown on the left of the graph and the various
flow rates assessed are shown across the top.
Horizontal bars on the graph depict projected
capability for each unit process, and the vertical
line represents the actual peak operating flow
experienced at the plant. Footnotes are used to
explain the loading criteria and conditions used to
rate the unit processes.
Figure 4-4. Example performance potential graph.
flOW (MGO)
Unit Process I 10 20 30 40 60 60
i « [ i I i i
Flocculation'
Sedimentation7
Filtration*
Disinfection"
Peak Instantaneous
£/Operating Flow
Rate = 45 MGD
Rated at 20 min hydraulic detention time (HOT); assumes
variable speed drive would be added to existing flocculator.
Rated at 0.6 gpm/sq ft surface overflow rate (SOR); 12.5 ft
depth.
Rated at 4 gpm/sq ft hydraulic loading rate (HLR); dual
media: assumes adequate media depth and backwashing
capability.
Rated at CT = 127 mg/L-min based on 2.4 mg/L CI2
residual, 53-min HOT, total 4 log Giardia reduction (1.5 log
by disinfection), pH = 8, temperature = 5 °C, 10% of
usable clearwell volume, and depth in clearwell maintained
> 9 feet.
27
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The approach to determine whether a unit process
is Type 1, Type 2 or Type 3 is based on the rela-
tionship of the position of horizontal bars to the
position of the peak instantaneous operating flow
rate. It is noted that if a plant operates at peak
instantaneous operating flow with one unit out of
service, then the evaluation would be based on
these conditions. As presented in Figure 4-5, a
unit process would be rated Type 1 if its projected
capability exceeds the peak instantaneous operat-
ing flow rate, Type 2 if its projected capability was
80 to 100 percent of peak, or Type 3 if its pro-
jected capability is less than 80 percent of peak.
Figure 4-5. Major unit process rating criteria.
Unit Process
Flocctilation
Sedinrt entati on
'Filtration
Disinfection
Bow
Type 1
Type 2
Type 1
^ e ^
Type 3 j
> 100% of pejkflow
80 - 100% of peak fl
j >10O'K. of p»«k flow
< 80% of peak flow
Peak InstafrtsneoMS operating Row Rate
&
4.2,2.3 Determining Peak instantaneous
Operating Flow
A key aspect of the major unit process evaluation
is the determination of peak instantaneous oper-
ating flow rate. This is the flow rate against which
the capability of each of the major unit processes
is assessed. Based on this assessment, the unit
process type is projected, which determines if
major construction will be required at the plant.
An additional evaluation of both the peak instanta-
neous operating flow rate and plant operating time
allows the evaluator to determine if plant capability
can be enhanced by reducing the plant flow rate
and extending the plant operating time. Some
plants only operate for part of the day and shut
down at night. In these cases, the peak instanta-
neous operating flow rate of the plant could be
occurring only over a 12-hour period, and the
plant may be able to operate at half the flow rate
for a 24-hour period. In this example, a unit proc-
ess that received a Type 3 rating may be able to
achieve Type 2 or Type 1 status. When a plant
decides to reduce flows, however, there probably
will be additional expenses for staff to operate the
plant for the extended time periods needed to
meet water demand. Basically the plant is trading
off the costs for staff with those required to con-
struct additional treatment capacity. In addition,
it may be possible for a community to take steps
to reduce demand by activities such as increasing
water rates, water rationing, or leak detection and
repair of their distribution system.
The peak instantaneous operating flow rate and
unit process loadings need to be carefully selected
and assessed by the evaluator since these parame-
ters in the unit process evaluation can direct the
utility ei.ther toward construction or pursuing opti-
mization with existing facilities. During a CPE
every effort should be made to direct the plant
toward optimization with existing facilities. In
completion of the major unit process evaluation,
this means that selection of pararneter(s) such that
it directs a plant to pursue major construction
should be made after much consideration of the
impacts on optimized performance and public
health protection.
Peak instantaneous operating flow rate is identified
through review of operating records and observa-
tion of operation practices and flow control capa-
bility. A review of plant flow records can be mis-
leading in determining peak instantaneous flow.
For example, records may indicate a peak daily
water production value, and discussions with the
operating staff may indicate that the plant was not
operated for a full 24-hour period. If the recorded
production was not for the full 24-hour period but
had been determined by calculating an average
flow rate over the 24-hour period, a rate that was
less than the actual peak instantaneous operating
flow would be identified. Peak instantaneous
operating flow is that flow rate which the unit
processes actually receive. For example, a plant
may have two constant speed raw water pumps
each capable of pumping at 1,000 gpm. If only
one is operated at a time for 12 hours per day, the
peak instantaneous flow rate would be established
at 1,000 gpm. If, however, operating personnei
indicate that a control valve is used to throttle the
pump to 750 gpm on a continuous basis, the peak
instantaneous flow rate would be established at
750 gpm. In a third situation the plant staff may
operate both pumps during times of the peak
water demand {e.g., summer) which ideally would
make the peak instantaneous flow rate
2,000 gpm. It is noted that the peak flow rate
when both pumps are operated is often lower than
when using a single pump, The maximum value
for the two pumps should be used even if the
28
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plant only operates this way for a few days at a
timo
time.
4.2.2.4 Rating Individual Unit Processes
The next step in preparing a performance potential
graph is selecting appropriate loading rates for
each of the major unit processes. Once the load-
ing rates are selected, the performance potential of
a unit process to achieve optimized performance
goals can be projected. The criteria presented in
Table 4-2 can be used to assist in selecting load-
ing rates for individual unit processes. There is a
wide range in the criteria which can translate into
large differences in the projected unit process
capabilities. Criteria to help in "adjusting" loading
rates for site-specific conditions are provided.
However, using the performance potential graph
approach requires a great deal of judgment on
behalf of an experienced water treatment plant
evaluator to properly project capability of a major
unit process.
It is noted that other resources are available to
assist less experienced evaluators in completing a
major unit process evaluation. One of these
resources is the Water Advisor expert system (2)
which prepares a major unit process evaluation
based on pre-selected loading rates. This pro-
gram, developed to assess plants based on 1989
SWTR compliance, is several years old; and the
loading rates have not been recently updated.
When using this program, the evaluator has no
opportunity to change loading rates based on the
unique conditions of a particular plant. An inexpe-
rienced evaluator may find this a useful tool to
check the major unit process evaluation completed
using the procedures in this handbook. A further
description of this software is contained in Appen-
dix B.
An additional resource is the Partnership for Safe
Water software (1). A copy of this software, as
well as a description of its use, is located in Ap-
pendix C. The Partnership for Safe Water soft-
ware provides suggested loading rates based on
industry standards and operating experience, but
also allows the CPE evaluator to easily change
loading rates and plot different performance poten-
tial graphs.
The criteria presented in Table 4-2 are considered
to be the most current, relative to achieving
Table 4-2. Major Unit Process Evaluation Criteria (1-2-3'4-5'6-71
Hydraulic
Flocculatlon Detention Time
Base
Single-Stage
Multiple Stages
Temp<=0.5°C
Temp >0.5°C
Temp<=0.5°C
Temp>0.5°C
20 minutes
30 minutes
25 minutes
20 minutes
15 minutes
Filtration Air Binding Loading Rate
Sand Media
Dual/Mixed Media
Deep Bed
(Typically anthracite
^>0 in. in depth)
None
Exists
None
Exists
None
Exists
2.0 gpm/ft2
1 .0-1 .5 gpm/ft2
4.0 gpm/ft2
2.0-3.0 gpm/ft2
6.0 gpm/ft2
3.0-4.5 gpm/ft2
Sedimentation (cold seasonal water <5°C)*
Conventional (circular and rectangular) and solids contact units
Operating Mode
Conventional Solids Contact Turbidity Removal
Depth Depth SOR
(ft) (ft) (gpm/ft2)
10 12-14 0.5
12-14 14-16 0.6
>14 >16 0.7
Softening
SOR
(gpm/ft2)
0.5
0.75
1.0
Color Removal
SOR
(gpm/ft2)
0.3
0.4
0.5
Conventional (circular and rectangular) and solids contact units -
with vertical (>45°) tube settlers
Operating Mode
Turbidity Removal
Depth SOR
(ft) (gpm/ft2)
10 1.0
12-14 1.5
>14 2.0
Softening
SOR
(gpm/ft2)
1.5
2.0
2.5
Color Removal
SOR
(gpm/ft2)
0.5
0.75
1.0
f long term (1 2 months) data monitoring indicates capability to meet performance goals at higher loading rates, then these rates can be used.
29
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optimized performance goals and are the criteria
that are used for development of the major unit
process evaluation for this handbook. However,
the performance of the unit process in meeting the
optimized performance goals should be a major
consideration in the selection of evaluation criteria.
The situation where a unit process continuously
performs at optimized levels should not be rated
as a Type 2 or Type 3 unit process merely based
on the criteria in Table 4-2. Specific guidance for
assessing each unit process is described in the
following sections.
Flocculation
Proper flocculation requires sufficient time to allow
aggregation of particles so that they are easily re-
moved in the sedimentation or filtration processes.
The capability of the flocculation process is pro-
jected based on the hydraulic detention time in
minutes required to allow floe to form at the low-
est water temperature. Judgment is used to ad-
just the selected times based on the type of treat-
ment plant, number of stages, and ability to con-
trol mixing intensity.
Selection of the required detention time for ade-
quate flocculation can vary widely depending on
water temperature. For example, at plants where
water temperatures of less than 5°C (41°F) occur,
floe formation can be delayed because of the cold
water. In these instances, longer (e.g., 30-minute)
detention times may be required. If temperatures
are not as severe, detention times as low as 15
minutes or less could be considered adequate.
Other factors to consider include the number of
flocculation stages and the availability of variable
energy input to control flocculation. A minimum
of three stages of flocculation is desirable. How-
ever, because the baffling and variable mixing
energy can often be added or modified through
minor modifications, these items are not consid-
ered as significant in determining the basin capa-
bility rating. Baffling a flocculation basin to better
achieve plug flow conditions can often signifi-
cantly improve the size and settleability of the floe.
If adequate basin volume is available (i.e., typically
a Type 1 unit process), a one-stage flocculation
basin may result in a Type 2 rating with the stipu-
lation that baffling could be provided to overcome
the single-stage limitation if it was shown to be
limiting in follow-up CTA activities.
The following guidelines are provided to aid in se-
lecting a hydraulic detention time to be used in
development of the flocculation unit process per-
formance potential:
. Desired hydraulic detention times for floe for-
mation are:
1 Typical range: 15 to 30 minutes.
• Cold low turbidity waters (e.g., <0.5° C
and < 5 NTU): 30 minutes or greater for
a conventional plant.
1 With tapered mixing and at least three
stages, use lower end of ranges. Twenty
minutes is commonly used for multiple
stages in temperate climates.
• With single-stage, use upper end of
ranges shown in Table 4-2.
• Lower hydraulic detention times than those
shown in Table 4-2 can be used to project
capacity in cases where plant data demon-
strates that the flocculation basin contributes
to the plant achieving the desired performance
goals at higher loading rates.
Sedimentation
Except for consistent low turbidity waters, sedi-
mentation is one of the multiple barriers normally
provided to reduce the potential of cysts from
passing through the plant. The sedimentation pro-
cess is assessed based on achieving a settled
water turbidity of less than 1 NTU 95 percent of
the time when the average raw water turbidity is
less than or equal to 10 NTU and less than 2 NTU
when the average raw water turbidity exceeds
10 NTU.
Sedimentation performance potential is projected
primarily based on surface overflow rate (SOB)
with consideration given to the basin depth, en-
hanced settling appurtenances (e.g., tube settlers),
and sludge removal mechanisms. Greater depths
generally result in more quiescent conditions and
allow higher SORs to be used (see Table 4-2).
Sludge removal mechanisms also must be consid-
ered when establishing an SOR for projecting
sedimentation capability. If sludge is manually
removed from the sedimentation basin(s),
additional depth is required to allow volume for
30
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sludge storage. For these situations, the selected
SOR should be lowered.
Sedimentation capacity ratings can be restricted to
certain maximum values because of criteria estab-
lished by state regulatory agencies on hydraulic
detention time. In these cases, state criteria may
be used to project sedimentation treatment capa-
bility. However, if data exists that indicates the
sedimentation basins can produce desired per-
formance at rates above the state rate, it may be
possible to obtain a variance from the state crite-
ria.
As shown in Table 4-2, the availability of or the
addition of tube or plate settlers in existing tank-
age can be used to enhance the performance
potential of the sedimentation process (e.g., per-
form at higher SORs). Upflow-solids-contact clari-
fiers represent a unique sedimentation configura-
tion since they contain both a flocculation and
sedimentation process that have been designed as
a single unit. These units can be rated using the
center volume to assess the flocculation capability
and the clarifier surface area to rate the sedimen-
tation capability.
The following guidelines are suggested to aid in
selecting a surface overflow rate to be used in the
development of the sedimentation unit process
capability.
. SORs to project performance potential for rec-
tangular, circular, and solids contact basins,
operating in a temperate climate with cold sea-
sonal water (< 5°C) are shown in Table 4-2.
• SORs to project performance potential for
basins with vertical (> 45°) tube settlers,
operating in a temperate climate with cold sea-
sonal water (< 5°C) are shown in Table 4-2.
• SORs for projecting performance potential of
proprietary settling units are:
. Lamella plates:
10 ft long plates with 2-inch spacing
at 55" slope
* 4 gpm/ft2 (based on surface area
above plates)
• Contact adsorption clarifiers (CACs):
* 6-8 gpm/ft2
Higher SORs than those shown in Table 4-2
can be used to project capability in cases
where plant data demonstrates that a sedimen-
tation basin achieves the desired performance
goals at these higher loading rates.
Filtration
Filtration is typically the final unit treatment proc-
ess relative to the physical removal of microbial
pathogens and, therefore, high levels of perform-
ance are essential from each filter on a continuous
basis. Filters are assessed based on their capa-
bility to achieve a treated water quality of less
than or equal to 0.1 NTU 95 percent of the time
(excluding the 15-minute period following back-
wash) based on the maximum values recorded
during 4-hour time increments. Additional goals
include a maximum filtered water turbidity follow-
ing backwash of less than or equal to 0.3 NTU
with a recovery to less than 0.1 NTU within 15
minutes.
The performance potential of the filtration process
is projected based on a filtration rate in gpm/ft2
which varies based on the type of media as shown
in Table 4-2. For mono-media sand filters a maxi-
mum filtration rate of 2 gpm/ft2 is used because
of the tendency of this filter to surface bind by
removing particles at the top of the filter. Dual or
mixed-media filters use a filtration rate of
4 gpm/ft2 because of their ability to accomplish
particle removal throughout the depth of the an-
thracite layer. Using the anthracite layer allows
higher filtration rates to be achieved while main-
taining excellent filtered water quality. Filtration
rates can be, and often are, restricted to certain
maximum values because of criteria established by
state regulatory agencies. In these cases, state
criteria may be used to project filter performance
potential. However, if data exists that indicates
the filters can produce desired performance at fil-
tration rates above the state rate, it may be possi-
ble to obtain a variance from the state criteria.
Limitations caused by air binding can also impact
the selected loading rate for projecting a filter's
performance potential and could bias the selected
loading rate toward more conservative values (see
Table 4-2). Air binding is a condition that occurs
in filters when air comes out of solution as a result
of pressure decreases or water temperature
increases (i.e., the water warms as it passes
through the filter. The air clogs the voids between
the media grains, which causes the filter to behave
31
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as though it were clogged and in need of back-
washing. The result is shorter filter runs and limi-
tations in hydraulic capability.
Inadequate backwash or surface wash facilities,
rate control systems, and media and underdrain
integrity are areas that can be addressed through
minor modifications. As such, these items are
assessed during a CPE as factors limiting perform-
ance and are typically not used to lower the filtra-
tion loading rate.
Disinfection
Disinfection is the final barrier in the treatment
plant, and is responsible for inactivating any
microbial pathogens that pass through previous
unit processes. For purposes of this handbook,
assessment of disinfection capability will be based
on the SWTR (8). The rule requires a minimum of
99.9 percent (3 log) inactivation and/or removal of
Giardia lamblia cysts and at least 99.99 percent (4
log) inactivation and/or removal of viruses. Under
the rule, each state was required to develop its
own regulations to assure that these levels of dis-
infection are achieved.
USEPA has published a guidance manual that pre-
sents an approach to assure that required levels of
disinfection are achieved (9). The approach uses
the concept of the disinfectant concentration (C)
multiplied by the actual time (T) that the finished
water is in contact with the disinfectant. In the
guidance manual, CT values are provided that can
be used, to project the various log removals for
various disinfectants at specific operating condi-
tions (e.g., temperature, pH, disinfectant residual).
The guidance manual also indicates that, while the
3-log and 4-1 og inactivation and/or removals are
the minimum required, the log inactivation and/or
removal may need to be increased if the raw water
source is subject to excessive contamination from
cysts and/or viruses, Cyst and virus removal
credits for the different types of treatment proc-
esses (e.g., conventional, direct filtration) are also
provided in the guidance manual.
The following procedures present an approach for
projecting the capability of a plant to meet the
disinfection requirements based on the CT values
presented in the SWTR guidance manual. Proce-
dures are presented for both pre- and post-disin-
fection, with pre-disinfection defined as adding the
disinfectant ahead of the filtration process and
post-disinfection defined as adding the disinfectant
following filtration. Whether or not a utility can
use pre-disinfection depends on how the utility's
state has developed its disinfection requirements.
Some states discourage pre-disinfection because
of concerns with disinfection by-products and the
possible ineffectiveness of disinfectants in un-
treated water. Other states allow pre-disinfection
because of concerns with the limited capabilities
of post-disinfection systems (e.g., limited contact
time). Although the approach used in this Hand-
book is based on the SWTR requirements, it is
important to note that the major unit process
evaluation for disinfection will have to be based on
the disinfection requirements adopted by the util-
ity's state regulatory agency.
Future regulations may affect the following
approach for assessing disinfection unit process
capability. CPE evaluators will need to carefully
assess and modify the following procedures as
more details concerning disinfection requirements
are established.
Post-Disinfection:
The following procedure is used to assess the
plant's disinfection capability when using only
post-disinfection.
. Project the total log Giardia reduction and inac-
tivation required by water treatment processes
based on the raw water quality or watershed
characteristics. Typically, Giardia inactivation
requirements are more difficult to achieve than
the virus requirements; consequently, Giardia
inactivation is the basis for this assessment.
State health departments may have established
these values for a specific plant. If not, the
standard requirement for a watershed of rea-
sonable quality is a 3.0 log reduction/
inactivation of Giardia cysts. A 4.0 or more
log reduction/inactivation may be required for
an unprotected watershed exposed to factors
such as wastewater treatment effluents.
• Project the log reduction capability of the ex-
isting treatment plant. Expected removals of
Giardia and viruses by various types of filtra-
tion plants are presented in Table 4-3. As
shown, a 2.5 log reduction may be allowed for
a conventional plant with adequate unit treat-
ment process capability (e.g., Type 1 units
preceding disinfection). If a Type 1 plant does
not exist, the evaluator may choose to lower
the projection of log removal capability for the
32
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facility. For purposes of the projection of
major unit process capability, it is assumed
that the plant will be operated to achieve
optimum performance from existing units.
Table 4-3. Expected Removals of Giardia Cysts
and Viruses by Filtration (9)
Filtration
Conventional
Direct
Slow Sand
Diatomaceous Earth
Expected Log Removals
Giardia
2.5
2.0
2.0
2.0
Viruses
2.0
1.0
2.0
1.0
SeJect a required CT value from the tables in
the SWTR guidance document (also provided
in Appendix D) based on the required log
reduction/inactivation, the log reduction capa-
bility projected for the plant, the maximum pH
and minimum temperature of the water being
treated, and the projected maximum disinfec-
tant residual. The maximum pH and the mini-
mum temperature, of the water being treated
are selected to ensure capability under worst
case conditions. When chlorine is used as the
disinfectant, the maximum residual utilized in
the evaluation should not exceed 2.5 mg/L
free residual, based on research which indi-
cates that contact time is more important than
disinfectant concentration at free chlorine
residuals above 2.5 mg/L (10). Maximum
chlorine residual may also be impacted by
maximum residuals tolerated by the consumer.
Using these parameters, calculate a required
detention time {e.g., CT required value divided
by the projected operating disinfectant resid-
ual) to meet the required CT. The following
equation is used to complete this calculation.
rrea(min) =
CTFea(mg/L-min)
Disinfectant Residual (mg/L)
Where:
T...
= Required detention time in post disinfection
unit processes.
CTreq = CT requirements from tables in Appendix D
for post disinfection conditions.
Disinfectant Residual = Selected operating residual
maintained at the discharge point from the
disinfection unit processes.
Select an effective volume of the existing
clearwell and/or distribution pipelines to the
first user. Effective volume refers to the vol-
ume of a basin or pipeline that is available to
provide adequate contact time for the disinfec-
tant. Effective volumes are calculated based
on worst case operating conditions using the
minimum operating depths, in the case of
basins. This is especially critical in plants
where high service pumps significantly change
the operating levels of the clearwell and in
plants that use backwash systems supplied
from the clearwell. Depending on the informa-
tion available, there are two ways to determine
the effective volume.
Some plants have conducted tracer studies to
determine the actual contact time of basins.
Adequate contact time is defined in the regula-
tions as T,,, which is the time it takes 10 per-
cent of a tracer to be detected in the basin
effluent (9). For these plants the effective
volume is the peak instantaneous operating
flow rate (gpm) multiplied by the T10 value
(min) determined from the tracer studies. If a
tracer study has been conducted, the results
should be utilized in determining the effective
contact time. It is important to note that the
tracer study results must also consider peak
instantaneous operating flows as well as
minimum operating depths in order to project
an accurate CT.
For those plants where tracer studies have not
been conducted, the effective volume upon
which contact time will be determined can be
calculated by multiplying the nominal clearwell
or pipeline volumes by a factor. Nominal vol-
umes are based on worst case operating con-
ditions. For example, an unbaffled clearwell
may have an effective volume of only 10%
(factor = 0.1) of actual basin volume because
of the potential for short-circuiting; whereas, a
transmission line could be based on 100% of
the line volume to the first consumer because
of the plug flow characteristics. A summary
of factors to determine effective volume is
presented in Table 4-4. Typically, for unbaf-
fled clean/veils a factor of 0.1 has been used
because of the fill and draw operational prac-
tices (e.g., backwashing, demand changes)
and the lack of baffles. A factor of 0.5 has
been used when calculating the effective vol-
ume of flocculation and sedimentation basins
when rating prechlorination, and a factor of
33
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1 .0 has been used for pipeline flow. However,
each disinfection system must be assessed on
individual basin characteristics, as perceived
by the evaluator. Caution is urged when using
a factor from Table 4-4 of greater than 0.1 to
project additional disinfection capability for
unbaff led basins. Available tracer test infor-
mation indicates that actual T10/T ratios in
typical full-scale clearwells are close to
10 percent of theoretical time (10).
Table 4-4. Factors for Determining Effective
Disinfection Contact Time Based on Basin
Characteristics* (9)
Baffling Condition
Unbaffled
Poor
Average
Superior
Excellent
Perfect (plug flow)
Factor Baffling Description
0.1 None; agitated basin, high
inlet and outlet flow
velocities, variable water
level
0.3 Single or multiple unbaf-
fled inlets and outlets,
no intra-basin baffles
0.5 Baffled inlet or outlet with
some intra-basin baffling
0.7 Perforated inlet baffle,
serpentine or perforated
intra-basin baffles, outlet
weir or perforated weir
0.9 Serpentine baffling
throughout basin.
1 .0 Pipeline flow.
'Based on hydraulic detention time at minimum operating
depth.
Calculate a flow rate where the plant will
achieve the required CT values for post-
disinfection. The following equation is used to
complete this calculation.
Treq(min)
Where:
Q
"post
Flow rate where required CT,,, can
be met.
Effective volume for post-disinfection
units.
Pre-Disinfection:
The following procedure is used to assess the
plant's disinfection capability when using pre-
disinfection along with post-disinfection. For pur-
poses of the calculations, the approach assumes
that the disinfection requirements can be met
independently by both pre- and post-disinfection;
and, therefore, these capabilities are additive when
projecting plant disinfection unit process capa-
bility. The procedure is used to determine the
additional disinfection capability provided if pre-
disinfection is actually being practiced at the utility
being evaluated. If pre-disinfection is practiced
and the utility is concerned about disinfection by-
products, the performance potential graph should
be developed with two bars for disinfection: one
including pre- and post-disinfection and one
including only post-disinfection capability. This
allows the evaluators and the utility to assess
capability if pre-disinfection was excluded.
• Project the total Jog Giardia reduction and inac-
tivation required by water treatment processes
based on the raw water quality or watershed
characteristics as presented in the post-
disinfection procedure.
• Project the log reduction capability of the ex-
isting treatment plant as presented in the post-
disinfection procedure.
• Select a required CT value for pre-disinfection
from the tables in the SWTR guidance docu-
men t. This value should be based on the
required log reduction, the log reduction capa-
bility of the plant, the maximum pH and mini-
mum temperature of the water being treated,
and the projected maximum disinfectant resid-
ual. The required pre-disinfection CT value
may be different than the post-disinfection
conditions if different temperatures, pHs, and
residuals exist for the two conditions (e.g.,
addition of lime or soda ash to increase the pH
of finished water would change the required
post-disinfection CT value relative to the pre-
disinfection value). CT values for inactivation
of Giardia cysts and viruses are presented in
Appendix D.
NOTE: If chlorine is used as the pre-
disinfectant, a 1.5 mg/L free chlorine residual
can be used as a value in the calculations
unless actual plant records support selection of
a different residual.
34
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Calculate Trtq (e.g., CT required value divided
by the projected operating disinfectant resid-
ual) as presented in the post-disinfection pro-
cedure.
Select an effective volume available to provide
adequate contact time for pre-disin feet/on.
Assess which basins and lines will provide
contact time. These are typically the floccula-
tion and sedimentation basins, but could
include raw water transmission lines if facilities
exist to inject disinfectant at the intake struc-
ture. Filters typically have not been included
because of the short detention times typically
inherent in the filters and the reduction in chlo-
rine residual that often occurs through filters.
However, increasingly plants are adding free
chlorine ahead of the filters and ammonia after
the filters to improve particle removal while
minimizing DBP formation. Free residuals of
2.0 mg/L in the filter effluent are common.
These residuals with a filter bed contact time
of 10 to 1 5 minutes may meet the majority, if
not all, of the CT requirement. The actual
basin volumes should be converted to effective
volumes by applying factors described in
Table 4-4 and discussed previously in the
post-disinfection procedure. Add the individ-
ual effective volumes together to obtain the
total effective pre-disinfection volume.
Calculate a flo w rate where the plant will
achieve the required CT values for both pre-
and post-disinfection using the formula below.
Use this flow rate to project the pre- and post-
disinfection system capability on the perform-
ance potential graph.
Vpre (gal)
Vpost (gal)
Q(gpm) =
Where:
Q = Flow rate where required CT,,, can be
met.
Vprs = Effective volume for pre-disinfection
units.
Vposf = Effective volume for post-disinfection
units.
4.2.3 Identification and Prioritization of
Performance Limiting Factors
423.1 Identification of Performance Limiting
Factors
A significant aspect of any CPE is the identifica-
tion of factors that limit the existing facility's per-
formance. This step is critical in defining the
future activities that the utility needs to focus on
to achieve optimized performance goals. To assist
in factor identification, a list of 50 different fac-
tors, plus definitions, that could potentially limit
water treatment plant performance are provided in
Appendix E. These factors are divided into the
four broad categories of administration, design,
operation, and maintenance. This list and defini-
tions are based on the results of over 70 water
treatment plant CPEs. Definitions are provided for
the convenience of the user and also as a refer-
ence to promote consistency in the use of factors
from plant to plant. If alternate names or defini-
tions provide a clearer understanding to those
conducting the CPE, they can be used. However,
if different terms are used, each factor should be
defined, and these definitions should be made
readily available to others conducting the CPE and
interpreting the results. Adopting and using a list
of standard factors and definitions as provided in
this handbook allows the effective comparison of
factors identified from different plants which will
enhance the usefulness of the findings for
improving water system performance on an area-
wide basis.
It is noted that several of the design factors refer
to capability of major unit processes. If the major
unit process evaluation resulted in a Type 2 or 3
classification for an individual unit process, these
results are also indicated in the CPE findings as an
identified factor limiting the existing facility's per-
formance. This also applies to those situations
where major unit processes are rated Type 1, but
have equipment-related problems that are limiting
performance. This would include key equipment
that needs to be repaired and/or replaced.
A CPE is a performance-based evaluation and,
therefore, factors should only be identified if they
impact performance. An observation that a utility
does not meet a particular "industry standard"
(e.g., utility does not have a documented preven-
tive maintenance program or does not practice
good housekeeping) does not necessarily indicate
that a performance limiting factor exists in these
35
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areas. An actual link between poor plant perform-
ance and the identified factor must exist.
Properly identifying a plant's unique list of factors
is difficult because the actual problems in a plant
are often masked. This concept is illustrated in
the following example:
A review of plant records revealed that a con-
ventional water treatment plant was periodically
producing finished water with a turbidity
greater than 0.5 NTU. The utility, assuming
that the plant was operating beyond its capa-
bility, was beginning to make plans to expand
both the sedimentation and filtration unit proc-
esses. Field evaluations conducted as part of a
CPE revealed that settled water and finished
water turbidities averaged about 5 NTU and
0.6 NTU, respectively. Filtered water tur-
bidities peaked at 1.2 NTU for short periods
following a filter backwash. Conceivably, the
plant's sedimentation and filtration facilities
were inadequately sized. However, further
investigation revealed that the poor perform-
ance was caused by the operator adding
coagulants at excessive dosages, leading to
formation of a pin floe that was difficult to set-
tle and filter. Additionally, the plant was being
operated at its peak capacity for only 8 hours
each day, further aggravating the washout of
solids from the sedimentation basins. It was
assessed that implementing proper process
control of the plant (e.g., jar testing for coagu-
lant control, calibration and proper adjustment
of chemical feed) and operating the plant at a
lower flow rate for a longer time period would
allow the plant to continuously achieve opti-
mized finished water quality. When the opera-
tor and administration were questioned about
the reasons that the plant was not operated for
longer periods of time, it was identified that it
was an administrative decision to limit the plant
staffing to one person. This limitation made
additional daily operating time as well as week-
end coverage difficult.
It was concluded that three major factors con-
tributed to the poor performance of the plant:
1. Application of Concepts and Testing to
Process Control: Inadequate operator
knowledge existed to determine proper
coagulant doses and to set chemical feed
pumps to apply the correct chemical dose.
2. Administrative Policies: A restrictive
administrative policy existed that prohibited
hiring an additional operator to allow
increased plant operating time at a reduced
plant flow rate.
3. Process Control Testing: The utility had
inadequate test equipment and an inade-
quate sampling program to provide process
control information.
In this example, pursuing the perceived limitation
regarding the need for additional sedimentation
and filtration capacity would have led to improper
corrective actions (i.e., plant expansion). The CPE
indicated that addressing the identified operational
and administrative factors would allow the plant to
produce a quality finished water on a continuous
basis without major expenditures for construction.
This example illustrates that a comprehensive
analysis of a performance problem is essential to
identify the actual performance limiting factors.
The CPE emphasis of assessing factors in the
broad categories of administration, design, opera-
tion, and maintenance helps to ensure the identifi-
cation of root causes of performance limitations.
The following sections provide useful observations
in identifying factors in these broad categories.
Identification of Administrative Factors
For purposes of a CPE administrative personnel are
those individuals who can exercise control over
water treatment but do not work "on-site" at the
plant on a day-to-day basis. This definition
includes personnel with job titles such as: off-site
superintendents, Directors of Public Works, coun-
cil personnel, mayors, etc.
The identification of administrative performance
limiting factors is a difficult and subjective effort.
Identification is primarily based on interpretation of
management and staff interview results. Typi-
cally, the more interviews that can be conducted
the better the interpretation of results will be. In
small plants the entire staff, budgetary personnel,
and plant administrators, including a minimum of
one or two elected officials, can be interviewed.
In larger facilities all personnel cannot typically be
interviewed, requiring the CPE evaluator to select
key personnel.
36
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Interviews are more effective after the evaluator
has been on a plant tour and has completed
enough of the data development activities (includ-
ing the performance assessment and major unit
process evaluations) to become familiar with plant
capabilities and past performance. With this
information, the evaluator is better informed to ask
insightful questions about the existing plant.
Accurately identifying administrative factors
requires aggressive but non-threatening interview
skills. The evaluator must always be aware of this
delicate balance when pursuing the identification
of administrative factors.
Policies, budgeting, and staffing are key mecha-
nisms that plant owners/administrators generally
use to implement their objectives. Therefore,
evaluation of these aspects is an integral part of
efforts to identify the presence of administrative
performance limiting factors.
Policies:
In order for a utility to strive for optimized per-
formance, there needs to be a commitment to
excellence in the form of supplying a high quality
treated water. This commitment must be based
on an understanding of the importance of water
treatment to the protection of public health.
Administrators must understand that to minimize
the potential for exposure of consumers to patho-
genic organisms in their drinking water, all unit
processes must be performing at high levels on a
continuous basis. Accordingly, administrators
should develop goals for high quality water and
should emphasize to the operating staff the impor-
tance of achieving these goals. Relative to par-
ticulate removal, administrators should encourage
pursuit of optimized performance goals as
described in this handbook.
Typically, all administrators verbally support goals
of low cost, safe working conditions; good plant
performance; and high employee morale. An
important question that must be answered is, "Is
priority given to water quality?" Often administra-
tors are more concerned with water quantity than
water quality, and this question can be answered
by observing the items implemented or supported
by the administrators. If a multi-million dollar
storage reservoir project is being implemented
while the plant remains unattended and neglected,
priorities regarding water quality and quantity can
be easily discerned.
An ideal situation is one in which the administra-
tors function with the awareness that they want
to achieve high quality finished water as the end
product of their treatment efforts. At the other
end of the spectrum is an administrative attitude
that "We just raised rates last year, and we aren't
willing to pursue additional revenues. Besides my
family used to drink untreated water from the river
and no one ever got sick." Also, plant administra-
tors may emphasize cost savings as a priority to
plant staff. The staff may be told to keep chemi-
cal cost down and to cut back if the finished water
turbidity falls below the regulated limit (i.e.,
0.5 NTU). For instance, one administrator indi-
cated to a plant superintendent that he would be
fired if he did not cut chemical costs. Administra-
tors who fall into this category usually are identi-
fied as contributing to inadequate performance
during an administrative assessment.
Another area in which administrators can signifi-
cantly, though indirectly, affect plant performance
is through personnel motivation. A positive influ-
ence exists if administrators: encourage personal
and professional growth through support of train-
ing; encourage involvement in professional organi-
zations; and provide tangible rewards for pursuing
certification. If, however, administrators eliminate
or skimp on essential operator training, downgrade
operator or other positions through substandard
salaries, or otherwise provide a negative influence
on staff morale, administrators can have a signifi-
cant detrimental effect on plant performance.
When the CPE evaluator finds that the operations
staff exhibit complacency, the role of the utility's
management in this situation needs to be
assessed. Utility management must support de-
velopment of a work environment that generates a
commitment to excellence as the best defense
against complacency. This requires involvement
of the entire utility to create an empowered staff
that can effectively respond to changing condi-
tions.
Utility administrators also need to be aware of the
impact that their policies have on treatment plant
performance. For example, at one small utility the
city manager forbid the plant operators to back-
wash filters more than once a week because
operating the backwash pump caused excessive
power demand and increased the utility's power
bill. This administrative policy's negative impact
on plant performance is obvious.
37
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When a plant is using key process equipment
(e.g., filter rate controllers) that appear to be anti-
quated and are impacting plant performance cur-
rently or potentially long-term, concerns with plant
reliability must be assessed. In these cases the
utility administrator's role in 'influencing the plant
to use the antiquated equipment past its useful life
should be determined. For example, utility admin-
istrators may have delayed replacement of the key
equipment way beyond its useful life because
there was no immediate problem and they wanted
to keep the utility's budget low. Identification of
this situation would be used to support an admin-
istrator's policies factor limiting performance.
Budgeting:
Minor plant modifications to address performance
problems identified by the utility staff can often
serve as a basis for assessing administrative fac-
tors limiting performance. For example, the plant
staff may have correctly identified needed minor
modifications for the facility and presented these
needs to the utility manager, but had their
requests declined. The CPE evaluator must solicit
the other side of the story from the administrators
to see if the administration is indeed non-
supportive in correcting the problem. There have
been numerous instances in which operators or
plant superintendents have convinced administra-
tors to spend money to "correct" problems that
resulted in no improvement in plant performance.
Smaller utilities often have financial information
combined with other utilities, such as wastewater
treatment, street repairs, and parks and recreation.
Additionally, nearly every utility's financial infor-
mation is set up differently. Therefore, it is neces-
sary to review information with the assistance of
plant and/or budgetary personnel to rearrange the
line items into categories understood by the
evaluator. Forms for comprehensively collecting
plant information, including financial information,
have been developed and are included in Appen-
dix F.
When reviewing financial information, it is impor-
tant to determine the extent of bond indebtedness
of the community and whether the rate structure
creates sufficient revenue to adequately support
the plant, Water system revenues should provide
an adequate number of fairly paid staff and exceed
expenditures enough to allow establishment of a
reserve fund for future plant modifications. Crite-
ria for determining key financial ratios for a utility
and guidance on their use are included in
Appendix F.
Staffing:
Administrators can directly impact performance of
a plant by providing inadequate staffing levels
such that there is not an operator at the plant
when it is in operation. Inadequate plant coverage
often results in poor performance since no one is
at the plant to adjust chemical dosages relative to
raw water quality changes. Non-staffed plant
operation can sometimes be justified if remote
monitoring associated with performance parame-
ters and alarm and plant shutdown capability
exists.
Identification of Desian Factors
Data gathered during a plant tour, review of plant
drawings and specifications, completion of design
information forms in Appendix F, and the com-
pleted evaluation of major unit processes, includ-
ing the performance potential graph, provide
information needed to assess design-related per-
formance limiting factors. Typically, the identifica-
tion of design factors falls into two categories:
major unit process limitations, as indicated by the
performance potential graph, and other design fac-
tors indicated in the list in Appendix E.
When considering identifying major unit process
limitations, the evaluator needs to exercise a great
deal of judgment since identification of these fac-
tors directs the utility toward construction alter-
natives. If at all possible, the evaluator should
assess options for operational alternatives (e.g.,
lower plant loading during periods where the raw
water quality is poor or extended operational time
to bring loading more in-line with assessed capa-
bility). This emphasis is especially true for Type 2
unit processes.
When the CPE evaluator has concerns with plant
reliability because the plant is using antiquated
process equipment, the root cause of the reliability
must be assessed beyond just identifying this as a
design factor. Typically, a reliability issue from
use of antiquated equipment is an administrative
factor. In rare cases preventive maintenance pro-
grams can lead to reliability problems.
Frequently, to identify design factors the evaluator
must make field evaluations of the various unit
38
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processes to assess design limitations. Identifica-
tion of these factors often offers great potential to
improve facility performance (e.g., baffling of
basins or improvement of flow splitting). Field
evaluations will be discussed later in this chapter.
It is important to note that any field evaluations
undertaken during a CPE should be completed in
cooperation with the plant staff. This approach is
essential since the evaluator may wish to make
changes that could improve plant performance but
could be detrimental to equipment at the plant.
Plant staff have worked and maintained the
equipment, are familiar with control systems, and
are in the best position to ascertain any adverse
impact of proposed changes.
Identification of Operational Factors
The approach and methods used in maintaining
process control can significantly affect perform-
ance of plants that have adequate physical facili-
ties (3,7). As such, identification of operationally-
based performance limiting factors offers the
greatest potential in improving the performance of
an existing utility. Information for identifying the
presence or absence of operational factors is
obtained throughout the CPE activities and
includes the plant tour, interviews, and the field
evaluation activities.
A plant tour provides an opportunity to initially
assess process control efforts. For example, the
process control capability of an operator can be
subjectively assessed during a tour by noting if the
operator discusses the importance of process
adjustments that are made to correlate with
changes in raw water quality. A solid foundation
for a viable process control program exists if the
operator presents this key information.
It is also important to assess issues of compla-
cency and reliability with respect to the staff's
process control capabilities. It is especially critical
to determine if all of the staff have the required
process control skills or if plant reliability is jeop-
ardized because only one person can make proc-
ess control decisions. Causes for this situation
could be administrative policies, staff technical
skills, or supervisory style.
After the tour, the focus of the identification of
operational factors is the assessment of the util-
ity's process control testing, data interpretation,
and process adjustment techniques. Key process
controls available to a water treatment plant
operator are flow rate; number of basins in serv-
ice; chemical selection and dosage; and filter
backwash frequency, duration and rate. Other
controls include flocculation energy input and
sedimentation sludge removal. Process control
testing includes those activities necessary to gain
information to make decisions regarding available
plant controls. Information to assist in evaluating
process control testing, data interpretation, and
process adjustment efforts is presented below.
Plant Flow Rate and Number of Basins in Service:
Plant flow rate dictates the hydraulic loading rate
on the various plant unit processes. In plants that
operate 24 hours each day, water demand dictates
water production requirements. However, many
small plants operate at maximum flow rates for
short (e.g., 8-hour) periods of time. Also, some
plants have multiple treatment trains, and flexi-
bility exists to vary the number in service. If the
operator is not aware that operating for longer
periods of time at a lower flow rate or increasing
the number of trains in service could improve plant
performance, an operations factor may be indi-
cated. Rapid increases in plant flow rate can also
have a significant effect on plant performance by
forcing particles through the filters.
Chemical Dose Control:
Chemical coagulants and flocculant and filter aids
are utilized to neutralize charges on colloidal parti-
cles and to increase the size and strength of parti-
cles to allow them to be removed in sedimentation
and filtration unit processes. Either overdosing or
underdosing these chemicals can result in a failure
to destabilize small particles, including pathogens,
and allow them to pass through the sedimentation
and filtration processes. If disinfection is inade-
quate to eliminate the pathogens that pass through
the plant, a significant public health risk exists.
Chemicals used for stabilization, disinfection, taste
and odor control, and fluoridation must also be
controlled.
The following are common indicators that proper
chemical application is not practiced:
. Calibration curves are not available for chemi-
cal feed pumps.
39
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Operations staff cannot explain how chemi-
cals, such as polymers, are diluted prior to
application.
Operations staff cannot calculate chemical
feed doses (e.g., cannot convert a mg/L
desired dose to Ib/day or ml/min to allow
proper setting of the chemical feeder).
Operations staff cannot determine the chemi-
cal feeder setting for a selected dose role.
Operations staff do not adjust chemical feed
rates for varying raw water quality conditions.
Chemicals are utilized in combinations that
have detrimental effects on plant performance.
An example is the practice of feeding lime and
alum at the same point without consideration
of the optimum pH for alum coagulation.
Chemicals are not fed at the optimum location
(e.g., non-ionic polymer fed before rapid mix
unit).
Chemical feed rates are not changed when
plant flow rate is adjusted.
Chemical coagulants are not utilized when raw
water quality is good (e.g., less than 0.5 to
1 NTU).
Filter Control:
The effectiveness of the filtration unit process is
primarily established by proper coagulant control;
however, other factors, such as hydraulic loading
rate and backwash frequency, rate, and duration,
also have a significant effect on filter performance.
Filters can perform at relatively high filtration rates
(e.g., 8 gpm/ft2) if the water applied is properly
conditioned (1 1, 12). However, because particles
are held in a filter by relatively delicate forces,
rapid flow rate changes can drive particles through
a filter, causing a significant degradation in per-
formance (7, 11, 12). Rapid rate changes can be
caused by increasing plant flow, by bringing a high
volume constant rate pump on-line, by a malfunc-
tioning filter rate control valve, or by removing a
filter from service for backwashing without reduc-
ing overall plant flow.
Filters must be backwashed periodically to prevent
accumulated particles from washing through the
filter or to prevent the filter from reaching terminal
headloss. Filters should be backwashed based on
effluent turbidity if breakthrough occurs before
terminal headloss to prevent the production of
poor filtered water quality. Backwash based on
headloss should be a secondary criteria. For
example, particles that are initially removed by the
filter are often "shed" when velocities and shear
forces increase within the filter as headloss accu-
mulates as the filter becomes "dirty." This signifi-
cant breakthrough in particles can be prevented by
washing a filter based on turbidity or particle
counting. Also, inadequate washing, both in
terms of rate and duration, can result in an accu-
mulation of particles in the filter, resulting in poor
filtered water quality. When a filter is continually
returned to service with a significant amount of
particles still within the media, these particles can
accumulate to form mudballs. The accumulation
of mudballs displaces filter surface area and raises
the filtration rate through those areas of the filter
where water can still pass. The filter can also
reach a point where minimal additional particles
can be removed because available storage sites
within the media already have an accumulation of
filtered particles. The evaluator must determine
whether inadequate washing is caused by a design
or an operational limitation. Field evaluations,
such as bed expansion and rise rate, that can be
conducted to determine the capability of backwash
facilities are discussed later in this chapter.
Another key process control activity is returning a
filter to service following a backwash. Since start-
up of filters can often result in loss of particles and
high turbidities, process control practices should
be developed to minimize this impact on perform-
ance. Operational practices that have provided
improved quality from filters during start-up have
included: ramping the backwash rate down in
increments to allow better media gradation, resting
a filter after backwash for several minutes or up to
several hours before putting the filter in service,
adding a polymer to the backwash water, and
slowly increasing the hydraulic loading on the filter
as it is brought back on line. These process con-
trol practices should be implemented and observed
at each utility to develop the optimum combination
of activities that provides the best filter perform-
ance.
The following are common indicators that proper
filter control is not practiced:
. Filters are started dirty (i.e., without back-
washing).
40
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• Rapid increases in overall plant flow rate are
made without consideration of filtered water
quality.
• Filter to waste capability is not being utilized
or is not monitored if utilized.
• Filters are removed from service without
reducing plant flow rate, resulting in the total
plant flow being directed to the remaining fil-
ters.
• Operations staff backwash the filters without
regard for filter effluent turbidity.
• Operations staff backwash at a low rate for a
longer period of time, or stop the backwash
when the filter is still dirty to "conserve"
water.
• Filters have significantly less media than speci-
fied, damage to underdrains or support grav-
els, or a significant accumulation of mudballs;
and these conditions are unknown to the oper-
ating staff because there is no routine exami-
nation of the filters.
• Operations staff cannot describe the purpose
and function of the rate control device.
Process Control Activities:
It is necessary for the operations staff to develop
information from which proper process adjust-
ments can be made. As a minimum, a method of
coagulation control must be practiced, such as jar
testing. Samples of raw water, settled water, and
individual filter effluent should be monitored for
turbidity. Operations staff that properly under-
stand water treatment should be able to show the
evaluator a recorded history of raw, settled, and
filtered water quality and jar test results; and be
able to describe how chemical dosages are deter-
mined and calculated and how chemical feeders
are set to provide the desired chemical dose.
They should also be able to explain how chemical
feed rates are adjusted, depending on raw water
quality.
Two similar factors are described in Appendix E
which often are difficult to discern when identify-
ing operational factors: Water Treatment Under-
standing and Application of Concepts and Testing
to Process Control. Identification of the proper
factor is key since follow-up efforts to address
each factor are different. Water Treatment Under-
standing is identified when the technical skills of
the staff are not adequate to implement proper
process control procedures. This limitation would
require training in the fundamentals of water
treatment. Application of Concepts and Testing to
Process Control is identified if the staff have basic
technical skills but are not appropriately applying
their knowledge to the day-to-day process control
of the unit processes. This factor can often be
best addressed with site-specific hands-on train-
ing.
The following are common indicators that required
process control activities are not adequately
implemented at a plant:
• Specific performance objectives for each major
unit process (barrier) have not been estab-
lished.
• A formalized sampling and testing schedule
has not been established.
• Data recording forms are not available or not
used.
• Jar tests or other methods (e.g., streaming
current monitor, zeta potential, or pilot filter)
of coagulation control are not practiced.
• The operator does not understand how to
prepare a jar test stock solution or how to
administer various chemical doses to the jars.
• The staff collects one sample per day for raw
water turbidity despite a rapidly changing raw
water source.
• Settled water turbidities are not measured or
are not measured routinely (e.g., minimum of
once each shift).
• Individual filtered water quality is not moni-
tored.
• Recycle water quality is not monitored or its
impact on plant performance is not controlled
(e.g., intermittent high volume recycle pump-
ing).
• Raw water used in jar testing does not include
recycle streams.
41
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There are no records available which document
performance of the individual sedimentation or
filtration unit processes.
Performance following backwash is not moni-
tored or recorded.
Recorded data are not developed or interpreted
(e.g., trend charts are not developed for
assessing unit process performance).
Calibration and other quality control proce-
dures are not practiced.
An emergency response procedure has not
been developed for the loss of chemical feeds
or for unacceptable finished water quality
occurrences.
Other Controls:
Other controls available to the operations staff
include rapid mixing, flocculation energy 'input,
sedimentation sludge removal, and disinfection
control. The following are indicators that these
controls are not fully utilized to improve plant per-
formance:
• The rapid mixer is shut down (e.g., to con-
serve power) and no other means exists to
effectively mix coagulant chemicals with raw
water (e.g., through a pump or prior to a
valve).
• Variable speed flocculation drives are not
adjusted (e.g., they remain at the setting
established when the plant was constructed).
• There is no routine removal of sludge from
sedimentation basins.
• There is no testing to control sludge quantities
in an upflow solids contact clarifier (e.g., rou-
tine sludge withdrawal is not practiced).
• Clean/veil or disinfection contact basin levels
are not monitored or maintained above a mini-
mum level to ensure that CT values can be
met.
Identification of Maintenance Factors
Maintenance performance limiting factors are typi-
cally associated with limitations in keeping critical
pieces of equipment running to ensure optimum
unit process performance or with reliability issues
related to a lack of ongoing preventive mainte-
nance activities.
Maintenance performance limiting factors are
evaluated throughout the CPE by data collection,
observations, and interviews concerning reliability
and service requirements of pieces of equipment
critical to plant performance. If units are out of
service routinely or for extended periods of time,
maintenance practices may be a significant con-
tributing cause to a performance problem. For
example, key equipment, such as chemical feed-
ers, require back-up parts and on-site skills for
repair to ensure their continued operation.
Another maintenance limitation could be a smaller
raw water pump that was out of service for an
extended period of time. In this example, the staff
may be forced to use a larger raw water pump
that overloads the existing unit processes during
periods of poor raw water quality.
Another key distinction to make when trying to
identify maintenance factors is to assess the qual-
ity of the preventive maintenance program relative
to the reliability of the equipment due to age.
Many utilities have excellent maintenance pro-
grams and personnel that have kept equipment
running long beyond its useful/reliable lifetime. In
these cases frequent breakdowns of the aging
equipment can lead to performance problems.
However, the root cause of the performance limi-
tation may be plant administrators that have made
a decision to forego the costs of replacement and
continue to force the plant to rely on the old
equipment. In this example, the CPE evaluator
must identify whether the lack of reliability is due
to poor maintenance or is an attitude related to the
administration staff.
4.2.3.2 Prioritization of Performance Limiting
Factors
After performance limiting factors are identified,
they are prioritized in order of their adverse impact
on plant performance. This prioritization estab-
lishes the sequence and/or emphasis of follow-up
activities necessary to optimize facility perform-
ance. For example, if the highest ranking factors
(i.e., those having the most negative impact on
performance) are related to physical limitations in
unit process capacity, initial corrective actions are
directed toward defining plant modifications and
obtaining administrative funding for their
42
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implementation. If the highest ranking factors are
process control-oriented, initial emphasis of follow-
up activities would be directed toward plant-
specific operator training.
Prioritization of factors is accomplished by a two-
step process, First, all factors that have been
identified are individually assessed with regard to
their adverse impact on plant performance and
assigned an "A", "B" or "C" rating (Table 4-5).
The summary of factors in Appendix E includes a
column to enter this rating. The second step of
prioritizing factors is to list those receiving "A"
rating in order of severity, followed by listing
those receiving "B" rating in order of severity.
"C" factors are not prioritized.
Table 4-5. Classification System for Prioritizing
Performance Limiting Factors
Rating
A
B
C
Classification
Major effect on a long term repetitive
basis
Mpderate effect on routine
effect on a periodic basis
basis or major
Minor effect
"A" factors are the major causes of performance
deficiencies and are the central focus of any sub-
sequent improvement program. An example "A"
factor would be an operations staff that has not
developed or implemented process control adjust-
ments to compensate for changing raw water
quality.
Factors are assigned a "B" rating if they fall in one
of two categories:
1. Those that routinely contribute to poor plant
performance but are not the major problem.
An example would be insufficient plant proc-
ess control testing where the primary problem
is that the operations staff does not sample
and test to determine process efficiency for
the sedimentation basins.
2. Those that cause a major degradation of plant
performance, but only on a periodic basis.
Typical examples are sedimentation basins that
cause periodic performance problems due to
excessive loading during spring run-off or a
short flocculation detention time that limits
floe formation during cold water periods.
Factors receive a "C" rating if they have a minor
effect on performance. For example, the lack of
laboratory space could be a "C" factor if samples
had to be taken off-site for analysis. The problem
could be addressed through the addition of bench
space and, thus, would not be a major focus
during follow-up activities.
A particular factor can receive an "A", "B", or "C"
rating at any facility, depending on the circum-
stances. For example, a sedimentation basin could
receive an "A" rating if its size was inadequate to
produce optimized performance under all current
loading conditions. The basin could receive a "B"
rating if the basin was only inadequate periodi-
cally, for example, during infrequent periods of
high raw water turbidity. The basin would receive
a "C" rating if the size and volume were adequate,
but minor baffling would improve the consistency
of its performance.
Typically, 5 to 10 unique factors are identified for
a particular CPE. The remaining factors that are
not identified as performance limiting represent a
significant finding. For example, in the illustration
that was previously presented in the Identification
of Performance Limiting Factors section of this
chapter, neither sedimentation nor filtration were
identified as performance limiting factors. Since
they were not identified, plant personnel need not
focus on sedimentation basin or filter modifica-
tions and the associated capital to upgrade these
facilities, Factors that are not identified are also a
basis for providing recognition to plant personnel
for adequately addressing these potential sources
of problems.
Once each identified factor is assigned an "A",
"B", or "C" classification, those receiving "A" or
"B" ratings are listed on a one-page summary
sheet (see Appendix El in order of assessed sever-
ity on plant performance. Findings that support
each identified factor are summarized on an at-
tached notes page. An example of a Factors
Summary Sheet and the attached notes is shown
in Figure 4-6. The summary of prioritized factors
provides a valuable reference for the next step of
the CPE, assessing the ability to improve perform-
ance, and serves as the foundation for imple-
menting correction activities if they are deemed
appropriate.
43
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All factors limiting facility performance may not be
identified during the CPE phase, it is often neces-
sary to later modify the original corrective steps as
new and additional information becomes available
during conduct of the performance improvement
phase (CTA).
4.2.4 Assessment of the Applicability of
a CTA
Proper interpretation of the CPE findings is neces-
sary to provide the basis for a recommendation to
pursue the performance improvement phase (e.g.,
Chapter 5). The initial step in assessment of CTA
applicability is to determine if improved perform-
ance is achievable by evaluating the capability of
major unit processes. A CTA is typically recom-
mended if unit processes receive a Type 1 or
Type 2 rating. However, if major unit processes
are deficient in capability (e.g., Type 3), ac-
ceptable performance from each "barrier" may not
be achievable; and the focus of follow-up efforts
may have to include construction alternatives,
Another important consideration with Type 3
facilities is the immediate need for public health
protection regardless of the condition of the plant.
Even if a facility has serious unit process deficien-
cies and antiquated equipment, the plant still has a
responsibility to protect public health until new
treatment processes are designed and constructed.
in these situations every effort should be made,
therefore, to operate around marginal unit proc-
esses and unreliable equipment if it represents the
best short-term solution for providing safe drinking
water. This concept is shown schematically in Fig-
ure 4-7.
Although all performance limiting factors can theo-
retically be eliminated, the ultimate decision to
conduct a CTA may depend on the factors that are
identified during the CPE. An assessment of the
list of prioritized factors helps assure that ail fac-
tors can realistically be addressed given the unique
set of factors identified. There may be reasons
why a factor cannot be approached in a straight-
forward manner. Examples of issues that may not
be feasible to address directly are: replacement of
key personnel, increases in rate structures, or
training of uninformed or uncooperative adminis-
trators to support plant needs. In the case of
recalcitrant administrators who refuse to recognize
the importance of water quality and minimizing
public health risk, regulatory pressure may be nec-
essary before a decision is made to implement a
CTA.
For plants where a decision is made to implement
a CTA, all performance limiting factors should be
considered as feasible to address. These are typi-
cally corrected with adequate "training" of the
appropriate personnel. The training is directed
toward the operations staff for improvements in
plant process control and maintenance, toward the
plant administrators for improvements in adminis-
trative policies and budget limitations, and toward
administrators and operations staff to achieve
minor facility modifications. Training, as used in
this context, describes activities whereby informa-
tion is provided to facilitate understanding and
implementation of corrective actions.
4.2.5 CPE Report
Results of a CPE are summarized in a brief written
report to provide guidance for utility staff and, in
some cases, state regulatory personnel. It is
important that the report be kept brief so that
maximum resources are used for the evaluation
rather than for preparation of an all-inclusive
report. The report should present sufficient infor-
mation to allow the utility decision-makers to initi-
ate efforts toward achieving desired performance
from their facility, it should not provide a list of
specific recommendations for correcting individual
performance limiting factors. Making specific rec-
ommendations often leads to a piecemeal
approach to corrective actions, and the goal of
improved performance is not achieved. For
Type 1 and Type 2 plants, the necessity of com-
prehensively addressing the combination of factors
identified by the CPE through a CTA should be
stressed. For Type 3 plants, a recommendation
for a more detailed study of anticipated modifica-
tions may be warranted. Appendix G demon-
strates a sample CPE report.
4.3 Conducting a CPE
A CPE involves numerous activities conducted
within a structured framework. A schematic of
CPE activities is shown graphically in Figure 4-8.
Initial activities are conducted prior to on-site
efforts and involve notifying appropriate utility
personnel to ensure that they, as well as neces-
sary resources, will be available during the CPE.
The kick-off meeting, conducted on-site, allows
the evaluators to describe forthcoming activities,
to coordinate schedules, and to assess availability
of the materials that will be required. Following
44
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Figure 4-6. Example factors summary and supporting notes.
CPE PERFORMANCE LIMITING FACTORS SUMMARY
Plant Name/Location: XYZ Water Treatment Plant
CPE Performed By: Process Applications, Inc.
CPE Date: June 15 - 18, 1998
Plant Type: Conventional with mixed media filters
Source Water: Wolf Creek
Performance Summary:
Plant was not able to meet the Surface Water Treatment Rule turbidity requirement of 0.5 NTU
95 percent of the time during March - May 1998. Optimized performance to achieve maximum
public health protection from microbial contaminants by producing a filtered water turbidity of
0.1 or less 95 percent of the time has not been achieved.
Ranking Table
Rank
1
2
3
4
5
Rating
A
A
A
A
B
Performance Limiting Factor (Category)
Alarm Systems (Design)
Process Flexibility (Design)
Policies (Administration)
Application of Concepts and Testing to Process Control
(Operation)
Process Instrumentation/Automation (Design)
Rating Description
A — Major effect on long-term repetitive basis.
B — Moderate effect on a routine basis or major effect on a periodic basis.
C — Minor effect.
45
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Figure 4-6. Example factors summary and supporting notes (continued).
Performance Limiting Factors Notes
Factor
Rating
Notes
Alarm Systems
No alarm/plant shutdown capability on chlorine feed,
chlorine residual, raw water turbidity, and finished water
turbidity.
Process Flexibility
Inability to select plant flow rate (e.g., set at
2,100 gpm).
No ability to feed filter aid polymer to the filters.
Inability to gradually increase and decrease backwash
flow rate.
Policies
Lack of established optimization goals (e.g., 0.1 NTU
filtered water turbidity) to provide maximum public
health protection and associated support to achieve
these performance goals.
Applications of Concepts and
Testing to Process Control
No sampling of clarifier performance.
inadequate testing to optimize coagulant type and
dosages.
No individual filter turbidity monitoring.
Starting "dirty" filters without backwash.
Incomplete jar testing to optimize coagulant dose.
Non-optimized feed point for flocculant aid addition.
Process Instrumentation/
Automation
No turbidimeters on individual filters.
Start and stop of filters without backwash or filter-to-
waste (due to storage tank demand).
Location of raw water turbidity monitor cell resulting in
inaccurate readings.
46
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Figure 4-7. CPE/CTA schematic of activities.
Plant Administrators or
Regulators Recognize Need
To Evaluate or Improve
Plant Performance
CPE Evaluation of
Major Unit Processes
I
Type 1
Major Unit Processes
Are Adequate
Type 2
Major Unit Processes
Are Marginal
Type 3
Major Unit Processes
Are Inadequate
Implement CTA to
Achieve Desired
Performance
From Existing Facilities
Implement CTA to
Optimize Existing Facilities
Before Initiating
Facility Modifications
Facility
Modifications;
Optimized Performance
Achieved
Evaluate Options For
Facility Modifications
Address Public Health
Related Factors
Facility
Modifications
Plus CTA
Activities
Abandon
Existing
Facilities and
Design New
Ones Plus
CTA
Activities
the kick-off meeting, a plant tour is conducted by
the superintendent or process control supervisor.
During the tour, the evaluators ask questions
regarding the plant and observe areas that may
require additional attention during data collection
activities. For example, an evaluator might make a
mental note to investigate more thoroughly the
flow splitting arrangement prior to flocculation
basins.
Following the plant tour, data collection activities
begin. Depending on team size, the evaluators
split into groups to facilitate simultaneous collec-
tion of the administrative, design, operations,
maintenance and performance data. After data are
collected, the performance assessment and the
major unit process evaluation are conducted. It is
noted that often the utility can provide the per-
formance data prior to the site visit. In this case
the performance graphs can be initially completed
prior to the on-site activities. However, it is
important to verify the sources of the samples and
quality of the data during field efforts.
Field evaluations are also conducted to continue to
gather additional information regarding actual plant
performance and confirm potential factors. Once
all of this information is collected a series of inter-
views are completed with the plant staff and
administrators. Initiating these activities prior to
the interviews provides the evaluators with an
understanding of current plant performance and
plant unit process capability, which allows inter-
view questions to be more focused on potential
factors.
47
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Figure 4-8. Schematic of CPE activities.
48
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After all information is 'collected, the evaluation
team meets at a location isolated from the utility
personnel to review findings. At this meeting, fac-
tors limiting performance of the plant are identified
and prioritized and an assessment of the applica-
bility of a follow-up CTA is made. The prioritized
list of factors, performance data, field evaluation
results, and major unit process evaluation data are
then compiled and copied for use as handouts
during the exit meeting. An exit meeting is held
with appropriate operations and administration
personnel where all evaluation findings are pre-
sented. Off-site activities include completing and
distributing the written report. A more detailed
discussion of each of these activities follows.
4.3.7 Overview
A CPE is typically conducted over a three to five-
day period by a team comprised of a minimum of
two personnel. A team approach is necessary to
allow a facility to be evaluated in a reasonable
time frame and for evaluation personnel to jointly
develop findings on topics requiring professional
judgment. Professional judgment is critical when
evaluating subjective information obtained during
the on-site CPE activities. For example, assessing
administrative versus operational performance lim-
iting factors often comes down to the evaluators'
interpretation of interview results. The synergistic
effect of two people making this determination is a
key part of the CPE process.
Because of the wide range of areas that are evalu-
ated during a CPE, the evaluation team needs to
have a broad range of available skills. This broad
skills range is another reason to use a team
approach in conducting CPEs. Specifically, per-
sons should have capability in the areas shown in
Table 4-6.
Regulatory agency personnel with experience in
evaluating water treatment facilities; consulting
engineers who routinely work with plant evalua-
tion, design and start-up; and utility personnel
with design and operations experience represent
the types of personnel with appropriate back-
grounds to conduct CPEs. Other combinations of
personnel can be used if they meet the minimum
experience requirements outlined above. Although
teams composed of utility management and opera-
tions personnel associated with the CPE facility
can be established, it is often difficult for an inter-
nal team to objectively assess administrative and
operational factors. The strength of the CPE is
best represented by an objective third party
review.
4.3.2 Initial A c tivities
The purpose of the initial activities is to establish
the availability of the required personnel and
documentation. To assure an efficient and com-
prehensive evaluation, key utility personnel and
Table 4-6. Evaluation Team Capabilities
Technical Skills
• Water treatment plant design
. Water treatment operations and
process control
Regulatory requirements
Maintenance
• Utility management (rates,
budgeting, planning)
Leadership Skills
. Communication (presenting, listening,
interviewing)
. Organization (scheduling, prioritizing)
Motivation (involving people, recognizing
abilities)
staff
• Decisiveness (completing CPE within time frame
allowed)
. Interpretation (assessing multiple inputs,
judgments)
making
49
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specific information need to be available. Required
information includes basic data on the plant
design, staffing and performance. A letter should
be sent to the utility describing the schedule of
activities that will take place and outlining the
commitment required of plant and administrative
staff. An example letter is presented in Appen-
dix H. Topics that are discussed in the letter are
presented below.
4.3.2.1 Key Personnel
It is necessary to have key people available during
the conduct of the CPE. The plant superintendent,
manager or other person in charge of the water
treatment facility must be available. If different
persons are responsible for plant maintenance and
process control, their presence should also be
required. These individuals should be available
throughout the three to five-day on-site activities.
A person knowledgeable about details of the utility
budget must also be available. A one- to two-hour
meeting with this person will typically be required
during the on-site activities to assess the financial
information. In many small communities, this per-
son is most often the City Clerk; in small water
districts it may be the Chairman of the Board or a
part-time clerk. In larger communities, the Finance
Director, Utilities Director, or Plant Superintendent
can usually provide the required information.
Availability of key administrative personnel is also
required. In many small communities or water
districts, an operator or plant superintendent may
report directly to the mayor or board chairman or
to the elected administrative body (e.g., City
Council or District Board). In larger communities,
the key administrative person is often the Director
of Public Works/Utilities, City Manager, or other
non-elected administrator. In all cases the admin-
istrator^) as well as representative elected offi-
cials who have the authority to effect a change in
policy or budget for the plant should be available
to participate in the evaluation. Typically these
people are needed for a one-half to three-quarter
hour interview and to attend the kick-off and exit
meetings.
4.3.2.2 CPE Resources
Availability of specific utility and plant information
is required during a CPE. The following list of the
necessary items should be provided to the utility
contact for review at the kick-off meeting and
before initiating on-site activities:
• Engineering drawings and specifications which
include design information on the individual
unit processes, and plant equipment.
• A plant flow schematic.
• Daily plant performance summaries showing
the results of turbidity measurements on raw,
settled, and filtered water for the most recent
twelve-month period.
• Financial information showing budgeted and
actual revenues and expenditures (i.e., chemi-
cals, salaries, energy, training), long-term debt,
water rates and connection fees.
• An organizational chart of the utility.
• A list of utility staff members.
In addition to the information listed, meeting and
work rooms are required during the conduct of the
CPE. A meeting room large enough for the evalua-
tion team and utility personnel should be available
for the kick-off and exit meetings. During the
CPE, a somewhat private work room with a table
and electrical outlets is desirable. Two or three
small rooms or offices are necessary for the indi-
vidual interviews.
Some facilities do not have a sample tap available
on the effluent from each individual filter. If these
taps are not available they should be requested
prior to the on-site activities. During the CPE,
existing taps should be checked to see if they are
functional. All taps both new and existing must
be located at points that assure a continuous sam-
ple stream that is representative of the filter efflu-
ent.
4.3.2.3 Scheduling
A typical schedule for on-site CPE activities for a
small to medium-sized water treatment facility is
presented below:
• First Day - a.m. (travel)
• First Day - p.m.:
• Conduct kick-off meeting.
50
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Conduct plant tour.
Set-up and calibrate continuous recording
turbidimeter (if available).
Coordinate location of CPE resources.
Second Day - a.m.:
Compile data on plant performance,
design, administration, operations and
maintenance.
Second Day - p.m.:
Continue data compilation.
Develop performance assessment and per-
formance potential graph.
Third Day - a.m.:
• Conduct interviews with plant staff and
utility officials.
. Conduct field evaluations.
Third Day- p.m.:
Shut down continuous recording turbi-
dimeter (if available).
Meet to identify and prioritize performance
limiting factors.
Prepare materials for exit meeting.
Fourth Day - a.m.:
. Conduct exit meeting.
Meet to debrief and make follow-up
assignments.
4.3.3 On-Site A c tivities
4.3.3.1 Kick-Off Meeting
A short (i.e., 30-minute) meeting between key
plant operations and administration staff and the
evaluators is held to initiate the field work. The
major purposes of this meeting are to present the
objectives of the CPE effort, to coordinate and
establish the schedule, and to initiate the adminis-
trative evaluation activities. Each of the specific
activities that will be conducted during the on-site
effort should be described. Meeting times for
interviews with administration and operations per-
sonnel should be scheduled. Some flexibility with
the interview schedules should be requested since
time for data development, which is essential prior
to conducting interviews, is variable from facility
to facility. A sign-up sheet (see Appendix F) may
be used to record attendance and as a mechanism
for recognizing names. Information items that
were requested in the letter should be reviewed to
ensure their availability during the CPE.
Observations that can contribute to the identifica-
tion of factors are initiated during the kick-off
meeting. More obvious indications of factors may
be lack of communication between the plant staff
and administration personnel or the lack of famili-
arity with the facilities by the administrators.
More subtle indications may be the priority placed
on water quality or policies on facility funding.
These initial perceptions often prove valuable
when formally evaluating administrative factors
later in the CPE effort.
4.3.3.2 Plant Tour
A plant tour follows the kick-off meeting. The
objectives of the tour include: 1 ) familiarize the
evaluation team with the physical plant; 21 make a
preliminary assessment of operational flexibility of
the existing processes and chemical feed systems;
and 3) provide a foundation for discussions on
performance, process control and maintenance
and continued observations that may indicate per-
formance limiting factors. A walk-through tour
following the flow through the plant (i.e., source
to clean/veil) is suggested. Additionally, the tour
should include backwash and sludge treatment
and disposal facilities, and the laboratory and
maintenance areas. The evaluator should note the
sampling points and chemical feed locations as the
tour progresses.
The CPE evaluation is often stressful, especially
initially, for plant personnel. Consequently, during
the conduct of a tour, as well as throughout the
on-site activities, the evaluation team should be
sensitive to this situation. Many of the questions
asked by the evaluation team on the plant tour are
asked again during formal data collection activities.
The plant staff should be informed that this repeti-
tiveness will occur. Questions that challenge cur-
rent operational practices or that put plant person-
nel on the defensive must be avoided. It is
51
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imperative that the CPE evaluators create an open,
non-threatening environment so that all of the
plant staff feel free to share their perspective as
various questions are asked. The evaluator should
try to maintain an information gathering posture at
all times. It is not appropriate to recommend
changes in facilities or operational practices during
the plant tour or the conduct of on-site activities.
This is often a challenge since the evaluation team
will frequently be asked for an opinion. Handle
these requests by stating that observations of the
CPE team will be presented at the conclusion of
the on-site activities after all information is col-
lected and analyzed.
The plant tour continues the opportunity for the
evaluator to observe intangible items that may
contribute to the identification of factors limiting
performance (i.e., operator knowledge of the plant
operation and facilities, relationship of process
control testing to process adjustments, the quality
of the relationships between various levels, etc.).
The tour also presents an opportunity to assess
the potential of using minor modifications to
enhance current facility capability. Suggestions to
help the evaluation team meet the objectives of
the plant tour are provided in the following sec-
tions.
Pretreatment
Pretreatment facilities consist of raw water intake
structures, raw water pumps, presedimentation
basins and flow measurement equipment. Intake
structures and associated screening equipment can
have a direct impact on plant performance. For
example, if the intake configuration is such that
screens become clogged with debris or the intake
becomes clogged with silt, maintaining a consis-
tent supply of water may be a problem. While at
the raw water source, questions should be asked
regarding variability of the raw water quality,
potential upstream pollutant sources, seasonal
problems with taste and odors, raw water quantity
limitations, and algae blooms.
Presedimentation facilities are usually only found
at water treatment plants where high variability in
raw water turbidities occurs. If plants are
equipped with presedimentation capability, basin
inlet and outlet configurations should be noted,
and the ability to feed coagulant chemicals should
be determined. Typically, most presedimentation
configurations lower turbidities to a consistent
level to allow conventional water treatment plants
to perform adequately. If presedimentation facili-
ties do not exist, the evaluator must assess the
capability of existing water treatment unit proc-
esses to remove variable and peak raw water tur-
bidities.
Raw water pumping should be evaluated regarding
the ability to provide a consistent water supply
and with respect to how many pumps are oper-
ated at a time. Frequent changing of high volume
constant speed pumps can cause significant
hydraulic surges to downstream unit processes,
degrading plant performance. In addition, opera-
tional practices as they relate to peak flow rates,
peak daily water production, and plant operating
hours should be discussed to assist in defining the
peak instantaneous operating flow rate.
Flow measurement facilities are important to accu-
rately establish chemical feed rates, wash water
rates, and unit process loadings. Questions
should also be asked concerning location, mainte-
nance, and calibration of flow measurement
devices. Discussions of changes in coagulant
dosages with changes in plant flow rate are also
appropriate at this stage of the tour.
Mixinq/Flocculation/Sedimentation
Rapid mixing is utilized to provide a complete
instantaneous mix of coagulant chemicals to the
water. The coagulants neutralize the negative
charges on the colloidal particles allowing them to
agglomerate into larger particles during the gentle
mixing in the flocculation process. These heavier
particles are then removed by settling in the quies-
cent area of the sedimentation basin. These
facilities provide the initial barrier for particle
removal and, if properly designed and operated,
reduce the particulate load to the filters, allowing
them to "polish" the water. During the tour,
observations should be made to determine if the
mixing, flocculation, and sedimentation unit proc-
esses are designed and operated to achieve this
goal. The evaluators should also observe flow
splitting facilities and determine if parallel basins
are receiving equal flow distribution.
Rapid mix facilities should be observed to deter-
mine if adequate mixing of chemicals is occurring
throughout the operating flow range. The opera-
tor should be asked what type of coagulants are
being added and what process control testing is
employed to determine their dosage. Observations
should be made as to the types of chemicals that
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are being added together in the mixing process.
For example, the addition of alum and lime at the
same location may be counter-productive if no
consideration is given to maintaining the optimum
pH for alum coagulation. If coagulant chemicals
are added without mixing, observations should be
made as to possible alternate feed locations, such
as prior to valves, orifice plates or hydraulic
jumps, where acceptable mixing might be
achieved.
When touring flocculation facilities, the evaluator
should note inlet and outlet conditions, number of
stages, and the availability of variable energy
input. Flocculation facilities should be baffled to
provide even distribution of flow across the basin
and to prevent velocity currents from disrupting
settling conditions in adjacent sedimentation
basins. If multiple stages are not available, the
capability to baffle a basin to create additional
staging should be observed. The ability to feed
flocculation aids to the gentle mixing portion of
the basin should be noted. The operator should be
asked how often flocculation energy levels are
adjusted or if a special study was conducted to
determine the existing levels. In the case of
hydraulic flocculation, the number of stages, the
turbulence of the water, and the condition of the
floe should be noted to determine if the unit proc-
ess appears to be producing an acceptable floe.
For upflow solids contact units, questions con-
cerning control of the amount of solids in the unit
and sludge blanket control procedures should be
asked.
Sedimentation basin characteristics that should be
observed during the tour include visual observa-
tions of performance and observations of physical
characteristics such as configuration and depth.
Performance observations include clarity of settled
water, size and appearance of floe, and presence
of flow or density currents. The general configu-
ration, including shape, inlet conditions, outlet
conditions, and availability of a sludge removal
mechanism should be observed. Staff should be
asked about process control measures that are
utilized to optimize sedimentation, including sludge
removal.
Chemical Feed Facilities
A tour of the chemical feed facilities typically
requires a deviation from the water flow scheme in
order to observe this key equipment. Often all
chemical feed facilities are located in a central
location that supplies various chemicals to feed
points throughout the plant. Chemical feed facili-
ties should be toured to observe the feed pumps,
day tanks, bulk storage facilities, flow pacing
facilities, and chemical feeder calibration equip-
ment. Availability of backup equipment to ensure
continuous feeding of each chemical during plant
operation should also be observed.
Filtration
Filters represent the key unit process for the
removal of particles in water treatment. Careful
observation of operation and control practices
should occur during the tour. The number and
configuration of filters should be noted, including
the type of filter media. The filter rate control
equipment should be observed and discussed to
ensure that it regulates filter flow in an even, con-
sistent manner without rapid fluctuations. The
flow patterns onto each filter should be noted to
see if there is an indication of uneven flow to indi-
vidual filters. Backwash equipment, including
pumps and air compressors, should be noted. The
availability of back-up backwash pumping is desir-
able to avoid interruptions in treatment if a break-
down occurs.
The operator should be asked how frequently fil-
ters are backwashed and what process control
procedures are used to determine when a filter
should be washed. Since turbidity represents an
indication of particles in the water, it should be the
parameter utilized to initiate a backwash unless
the plant has on-line particle counters. The opera-
tor's response to this inquiry helps to demonstrate
his understanding and priorities concerning water
quality.
The tour guide should also be questioned con-
cerning the backwash procedure and asked if all
operators follow the same technique. The
evaluation team should determine if filter to waste
capability exists and, if so, how it is controlled.
Questions concerning individual filter monitoring
should also be asked. The availability of turbidity
profiles following backwash should be determined.
Some facilities utilize particle counting to assess
filter performance, and the availability of this
monitoring tool should be determined during the
plant tour.
The tour is an excellent time to discuss the selec-
tion of a filter and the location of the sampling
point for continuous turbidity monitoring to be
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conducted during the field evaluation activities.
Ideally, the filter that is most challenged to pro-
duce high quality water should be monitored by
the evaluation team. Often, the operational staff
will be able to quickly identify a "problem filter."
Disinfection
The evaluation team should tour disinfection facili-
ties to become familiar with the equipment feed
points and type of contact facilities. Special atten-
tion should be given to the configuration and baf-
fling of clearwells and finished water reservoirs
that provide contact time for final disinfection.
Observation of in-line contact time availability
should be made by noting the proximity of the
"first user" to the water treatment plant. Often,
distribution piping cannot be used in the assess-
ment of contact time since the plant staff repre-
sents the first user.
The availability of back-up disinfection equipment
should be determined to assess the capability of
providing an uninterrupted application of disinfec-
tant. The addition of a disinfectant prior to filtra-
tion, either as an oxidizing agent or disinfectant,
should also be noted. The capability to automati-
cally control the disinfection systems by flow
pacing should be determined.
Backwash Water and Sludge Treatment and
Disposal
The location of any recycle streams should be
identified during the tour. Recycle of water should
be assessed with respect to the potential for
returning a high concentration of cysts to the plant
raw water stream. Since this practice represents a
potential risk, the evaluator should determine the
method of treatment or other methods used to
handle the impact of recycle streams (e.g., storage
for equalization of flows with continuous return of
low volumes of recycle to the raw water). It is
also important to assess if plant piping allows col-
lection of a representative sample of recycle to be
used in jar tests to determine coagulant dose.
Typically, the main sources of recycle flows are
the settled filter backwash water and sedimenta-
tion basin sludge decant. If these streams are dis-
charged to a storm sewer system or a waterway,
questions should be asked to determine if the dis-
charge is permitted and if permit requirements are
being complied with. If recycle treatment facilities
exist, questions should be asked to determine the
method of controlling the performance of these
facilities.
Laboratory
The laboratory facilities should be included as part
of the plant tour. Source water and performance
monitoring, process control testing, and quality
control procedures should be discussed with labo-
ratory personnel. It is especially important to
determine if turbidity measurements represent
actual plant performance. The use of laboratory
results should be discussed and a review of the
data reporting forms should also be made. The
laboratory tour also offers the opportunity to
assess the availability of additional plant data that
could be used to assess plant performance (e.g.,
special studies on different coagulants, individual
turbidity profiles), Available analytical capability
should also be noted. An assessment should also
be made if all of the analytical capability resides in
the laboratory and, if so, does the operations staff
have sufficient access to make process control
adjustments?
Maintenance
A tour of the maintenance facilities provides an
opportunity to assess the level of maintenance
support at the plant. Tools, spare parts availa-
bility, storage, filing systems for equipment cata-
logues, general plant appearance, and condition of
equipment should be observed. Questions on the
preventive maintenance program, including meth-
ods of initiating work (e.g., work orders), are
appropriate. Equipment out of service should also
be noted.
4.3.3.3 Data Collection Activities
Following the plant tour, data collection proce-
dures are initiated. Information is collected
through discussions with plant and administrative
staff utilizing a formalized data collection format as
shown in Appendix F. Categories covered by
these forms are listed below:
. Kick-Off Meeting
. Administration Data
. Design Data
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Operations Data
Maintenance Data
Field Evaluation Data
Interview Guidelines
Exit Meeting
When collecting information requested on the
forms, the evaluation team should solicit the par-
ticipation of the most knowledgeable person in
each of the evaluation areas. For example, those
persons actually implementing the maintenance
activities should be included in the maintenance
data collection efforts.
When collecting information, the evaluator should
be aware that the data are to be used to evaluate
the performance capability of the existing facilities.
The evaluator should continuously be asking "How
does this information affect plant performance?".
If the area of inquiry appears to be directly related
to plant performance, the evaluator should spend
sufficient time to fully develop the information.
Often this pursuit of information will go beyond
the constraints of the forms. In this way, some of
the most meaningful information obtained is "writ-
ten on the back of the forms."
4.3.3.4 Evaluation of Major Unit Processes
An evaluation of the plant's major unit processes
is conducted to determine the performance poten-
tial of existing facilities at peak instantaneous
operating flow. This is accomplished by develop-
ing a performance potential graph and rating the
major unit processes as Type 1, 2, or 3, as previ-
ously discussed in 4.2.2 Evaluation of Major Unit
ProcessBS.
It is important that the major unit process evalua-
tion be conducted early during the on-site activi-
ties, since this assessment provides the evaluator
with the knowledge of the plant's treatment capa-
bility. If the plant major unit processes are deter-
mined to be Type 1 or 2 and they are not per-
forming at optimum levels, then factors in the
areas of administration, operation or maintenance
are likely contributing to the performance prob-
lems. The completed major unit process assess-
ment aids the evaluation personnel in focusing
later interviews and field evaluations to identify
those performance limiting factors.
4.3.3.5 Performance Assessment
An assessment of the plant's performance is made
by evaluating existing recorded data and by con-
ducting field evaluations to determine if unit proc-
ess and total plant performance have been opti-
mized. Typically, the most recent twelve months
of existing process control data is evaluated and
graphs are developed to assess performance of the
plant. Additional data (e.g., backwash turbidity
profiles, particle counting data, individual filter 24-
hour continuous turbidimeter performance) can be
developed if they aid in the determination of the
existing plant performance relative to optimized
goals. Evaluations are also conducted during the
performance assessment activities to determine if
existing plant records accurately reflect actual
plant-treated water quality. Calibration checks on
turbidimeters or a review of quality control proce-
dures in the laboratory are part of these evalua-
tions.
It is conceivable that a public health threat could
be indicated by the data during the development of
the data for the performance assessment compo-
nent. The CPE evaluation team will have to handle
these situations on a case-by-case basis. An
immediate discussion of the potential threat should
be conducted with the plant staff and administra-
tion and they should be encouraged to contact the
appropriate regulatory agency. Voluntary actions
such as plant shut-down or a voluntary boil water
notice should also be discussed. It is important
that the CPE evaluation team not assume respon-
sibility for the process adjustments at the plant.
Another key part of the performance assessment
is the use of a continuous recording turbidimeter
during the conduct of the on-site activities. This
effort will be further described in the next section
of this chapter. A detailed discussion of the
methods utilized in the performance assessment
was presented previously in the Assessment of
Plant Performance section of this chapter.
4.3.3.6 Field Evaluations
Field evaluations are an important aspect of the
on-site activities. Typically, field evaluations are
conducted to verify accuracy of monitoring and
flow records, chemical dosages, record drawings,
filter integrity, and backwash capability. Forms to
assist in the documentation of the data collected
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during field evaluations have been included in
Appendix F.
Performance monitoring records can be verified by
utilizing a continuous recording turbidimeter to
assess an individual filter's performance over a
twenty-four hour period. A backwash cycle is
conducted during this monitoring effort. It is
important that the evaluation team acquire or have
made available to them a properly calibrated tur-
bidimeter to support this field effort. If a recording
on-line turbidimeter is not available, an instrument
that allows individual analysis of grab samples can
be used. If the evaluation team does not have
access to a turbidimeter, the plant's turbidimeter,
which must be calibrated prior to the sampling and
testing activities, can be used.
Treated water quality obtained from the field
evaluation can be compared with recorded data to
make a determination if performance monitoring
records accurately represent treated water quality.
Differences in actual versus recorded finished
water quality can be caused by sampling location,
sampling time, sampling procedures, and testing
variations. The evaluation team's instrument can
also be used to assess the plant's turbidimeter and
calibration techniques.
The accuracy of flow records can be verified by
assessing the calibration of flow measurement
equipment. This is often difficult because of the
type of meters utilized (e.g., propeller, venturi,
magnetic). If these types of meters are utilized, it
may be necessary to require a basin to be filled or
drawn down over a timed period to accurately
check the metering equipment. If accuracy of
metering equipment is difficult to field-verify, the
frequency of calibration of the equipment by the
plant staff or outside instrumentation technicians
can be evaluated. If flow metering equipment is
being routinely (e.g., quarterly or semiannually)
calibrated, flow records typically can be assumed
to be accurate.
Dosages of primary coagulant chemicals should be
verified. Feed rates from dry feeders can be
checked by collecting a sample for a specified time
and weighing the accumulated chemical. Simi-
larly, liquid feeders can be checked by collecting a
sample in a graduated cylinder for a specified time.
In both cases the feed rate in Ib/min or mL/min of
chemical should be converted to mg/L and com-
pared with the reported dosage. During this
evaluation the operating staff should be asked
how they conduct chemical feed calculations, pre-
pare polymer dilutions, and make chemical feeder
settings. Additionally, the plant staff should be
asked how they arrived at the reported dosage. If
jar testing is used, the evaluation team should dis-
cuss this procedure, including preparation of stock
solutions. Often, a discussion can be used to
assess the validity and understanding of this
coagulation control technique. Performing jar
tests is typically not part of the CPE process.
The integrity of the filter media, support gravels,
and underdrain system for a selected filter should
be evaluated. This requires that the filter be
drained and that the evaluation team inspect the
media. The filter should be investigated for sur-
face cracking, proper media depth, mudballs and
segregation of media in dual media filters. The
media can be excavated to determine the depth of
the different media layers in multi or dual media
filters. The media should be placed back in the
excavations in the same sequence that it was
removed. The filter should also be probed with a
steel rod to check for displacement of the support
gravels and to verify the media depth within the
filter. Variations in depth of support gravels of
over two inches would signify a potential problem.
Variations in media depth of over two incl-ies
would also indicate a potential problem. If possi-
ble, the clear well should be observed for the
presence of filter media. Often, plant staff can
provide feedback on media in the clearwell if
access is limited. If support gravels or media loss
are apparent, a more detailed study of the filter
would then be indicated, which is beyond the
scope of a CPE.
Filter backwash capability often can be determined
from the flow measurement device on the back-
wash supply line. If this measurement is in ques-
tion or if the meter is not available, the backwash
rate should be field-verified by assessing either the
backwash rise rate or bed expansion. Rise rate is
determined by timing the rise of water for a spe-
cific period. For example, a filter having a surface
area of 150 ft2 would have a backwash rate of
20 gpm/ft2 if the rise rate was 10.7 inches in
20 seconds. This technique is not suitable for
filters where the peak backwash rate is not
reached until the washwater is passing over the
troughs.
Bed expansion is determined by measuring the
distance from the top of the unexpanded media to
a reference point (e.g., top of filter wall) and from
the top of the expanded media to the same refer-
ence point. The difference between these two
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measurements is the bed expansion. A variety of
techniques can be used to determine the top of
the expanded bed. A light-colored can lid attached
to the end of a pole is effective. The bed expan-
sion measurement divided by the total depth of
expandable media (i.e., media depth less gravels)
multiplied times 100 gives the percent bed expan-
sion. A proper wash rate should expand the filter
media a minimum of 20 to 25 percent (4).
Record drawings may have to be field-verified by
measuring basin dimensions with a tape measure if
there is doubt as to their accuracy. If no drawings
are available, all basin dimensions will have to be
measured.
Additional field tests such as verification of equal
flow splitting and calibration of monitoring or labo-
ratory equipment can also be conducted. Field
verification to support identified factors limiting
performance should always be considered by the
evaluation team; however, time requirements for
these activities must be weighed against meeting
the overall objectives of the CPE.
4.3.3.7 Interviews
Prior to conducting personnel interviews, it is nec-
essary to complete the data collection forms, the
major unit process evaluation, and performance
assessment. This background information allows
the evaluator to focus interview questions on
anticipated factors limiting performance. It is also
advantageous for the CPE evaluators to be familiar
with the factors outlined in Appendix E prior to
conducting the interviews. This awareness also
helps to focus the interviews and to maintain the
performance emphasis of the interview process.
For example, an adamantly stated concern
regarding supervision or pay is only of significance
if it can be directly related to plant performance.
Unless the number of the utility staff is too large,
interviews should be conducted with all of the
plant staff and with key administrative personnel
in order to obtain feedback from both resources.
Example key administrators include the mayor,
board members from the Water Committee, and
the Utility Director.
Interviews should be conducted privately with
each individual. The persons being interviewed
should be informed that the responses are pre-
sented in the findings as an overall perception, and
individual responses are not utilized in the exit
meeting or final report. Approximately 30 to 45
minutes should be allowed for each interview.
Interviews are conducted to clarify information
obtained from plant records and on-site activities
and to ascertain differences between real or per-
ceived problems. Intangible items such as com-
munication, administrative support, morale, and
work attitudes are also assessed during the inter-
view process. The interviews also offer an oppor-
tunity to ask questions about potential factors.
During the conduct of on-site activities, the CPE
evaluators begin to form preliminary judgments.
The interviews offer the opportunity to ask, in an
information gathering forum, what the utility per-
sonnel may think of the perceived limitation. An
adamant response may justify additional data col-
lection to strengthen the evaluation team's convic-
tions prior to the exit meeting. On the other hand,
sensitive findings such as operational and adminis-
trative limitations can be introduced in a one-on-
one setting and will allow the affected parties to
be aware that these issues may be discussed at
the exit meeting.
Interview skills are a key attribute for CPE evaluat-
ors. Avoidance of conflict, maintaining an infor-
mation gathering posture, utilizing initial on-site
activity results, creating an environment for open
communication, and pursuing difficult issues (e.g.,
supervisory traits) are a few of the skills required
to conduct successful interviews. An additional
challenge to the CPE evaluators is to avoid pro-
viding "answers" for the person being interviewed.
A major attribute is the ability to ask a question
and wait for a response even though a period of
silence may exist.
A key activity after conducting several interviews
is for the evaluation team members to discuss
their perceptions among themselves. Often, con-
flicting information is indicated, and an awareness
of these differences can be utilized to gather addi-
tional information in remaining interviews. To
assist in conducting interviews, guidelines have
been provided in Appendix F - Interview Guide-
lines.
4.3.3.8 Evaluation of Performance Limiting
Factors
The summarizing effort of the on-site activities is
identification and prioritization of performance lim-
iting factors. This activity should be completed at
a location that allows open and objective
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discussions to occur (e.g., away from utility
personnel). Prior to the discussion, a debriefing
session that allows the evaluation team to discuss
pertinent findings from their respective efforts
should be held. This step is especially important
since each team member is typically not involved
in every aspect of the CPE. All data compiled
during the evaluations should be readily available
to support the factor identification efforts.
The checklist of performance limiting factors pre-
sented in Appendix E, as well as the factor defini-
tions, provides the structure for an organized
review of potential factors in the evaluated facility.
The intent is to identify, as clearly as possible, the
factors that most accurately describe the causes
of limited performance. Often, a great deal of dis-
cussion is generated in this phase of the CPE
effort. Sufficient time (i.e., 2 to 8 hours) should
be allocated to complete this step, and all opinions
and perceptions should be solicited. It is particu-
larly important to maintain the performance focus
during this activity. A natural bias is to identify all
factors that may have even a remote application at
the current facility. Persons new to this phase of
a CPE often want to make sure that they do not
miss anything in identifying deficiencies. An
excellent method to maintain focus is to remember
that the list of factors is the evaluation team's
attempt to prioritize the future efforts for the
utility. If the total number of factors is greater
than 10, the evaluation team should reassess the
factors identified and look for ways to clarify the
message that will be sent during the exit meeting.
One option would be to combine factors and use
the examples given when the factor was identified
to provide greater justification as to why the
"combined factor" is limiting performance.
Another incentive to reduce the number of factors
is that extraneous factors can confuse the utility's
future activities and divert focus from priority
optimization efforts. Often, it is the factors that
are not identified that are important since by not
identifying factors, the team discourages future
emphasis in these areas.
One of the most difficult challenges facing a CPE
evaluator can be the identification of administra-
tive factors since the team may find itself criticiz-
ing high level administrators and the culture that
they have created. This can be especially difficult
in situations where these same administrators
have contracted for the CPE and may be current
and future clients. Given these pressures, the CPE
team may find themselves avoiding identifying any
administrative factors when there is clear evidence
that the administrator in question is having a direct
impact on performance. If a CPE team finds
themselves in this situation they should review
their responsibility in protecting public health and
the long term good that will occur if the adminis-
trative factors are addressed. Those responsible
for the review of CPE reports should also question
a CPE report that fails to identify any administra-
tive factors.
Each factor identified as limiting performance
should be assigned an "A", "B", or "C" rating.
Further prioritization is accomplished by complet-
ing the Summary Sheet presented in Appendix E.
Only those factors receiving either an "A" or "B"
rating are prioritized on this sheet. A goal of the
prioritization activity is to provide a clear story and
an associated clear set of priorities for the utility to
use to pursue optimized performance at the con-
clusion of the CPE. Additional guidance for iden-
tifying and prioritizing performance limiting factors
was provided in the Identification and Prioritization
of Performance Limiting Factors section previously
discussed in this chapter.
4.3.3.9 Exit Meeting
Once the evaluation team has completed the on-
site activities, an exit meeting should be held with
the plant administrators and staff. A presentation
of CPE results should include descriptions of the
following:
• Overview of optimized treatment goals
• Plant performance assessment
• Evaluation of major unit processes
• Prioritized performance limiting factors
• Assessment of applicability of follow-up
The overview of optimized treatment goals is pre-
sented to establish the basis upon which the utility
was evaluated. It is important to identify that the
CPE evaluation was based on goals, likely more
stringent than the plant was designed for and
more stringent than regulated performance criteria.
The positive public health aspects of achieving this
level of performance should also be discussed.
Chapter 2 described the optimized performance
goals and the public health benefits of achieving
these goals. A synopsis of this information should
be presented at the beginning of the exit meeting.
A brief presentation on the function of each water
treatment unit process and the effort required to
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produce acceptable finished water quality can also
be made to enhance water treatment understand-
ing for the administrators.
Handouts, based on information developed during
the on-site activities, can be utilized to assist in
presenting the other exit meeting topics. Graphs
are effective for presenting the performance
assessment findings. Typically, the time versus
turbidity plots (one year of data) and percentile
plots for raw, settled and filtered and/or finished
water are presented. Additionally, results of field
evaluations such as turbidity profiles following a
filter backwash, 24-hour individual filter perform-
ance profiles, or particle counting data may be
presented. The objective of this portion of the exit
meeting is to clearly establish the utility's historical
and existing performance relative to optimized per-
formance goals. If optimized performance is not
being achieved, this presentation establishes the
foundation for the remaining exit meeting topics.
If the CPE reveals that the treatment plant per-
formance represents a significant health risk, this
should be carefully explained to the utility staff.
Regulatory personnel conducting such a CPE
should determine if administrative or regulatory
action should be implemented and should establish
a time frame to protect public health (e.g., imme-
diately).
The performance potential graph summarizes the
major unit process evaluation. If Type 1 unit pro-
cesses are indicated, the utility participants can be
told that physical facilities were not determined to
be limiting the plant's ability to achieve optimized
performance goals. Type 2 unit processes do not
necessarily indicate a construction need, and the
potential of "operating around" these deficiencies
can be presented. Type 3 unit processes demon-
strate the need for construction alternatives.
The summary of prioritized performance limiting
factors and a supplemental summary of key points
that were used to identify these factors are the
handouts utilized for this portion of the exit
meeting. Throughout the presentation, the evalua-
tor must remember that the purpose is to identify
and describe facts to be used to improve the cur-
rent situation, not to place blame for any past or
current problems. Depending on the factors iden-
tified, this portion of the exit meeting can be the
most difficult to present. Factors in the areas of
operation and administration offer the greatest
challenge. The evaluation team must "tell it like it
is" but in a constructive and motivational manner.
Little impact can be expected if this presentation is
softened to avoid conflict or adverse feedback
from the utility staff. At the same time, it is also
important that the factors not be presented so
harshly that it creates an overly hostile environ-
ment, where the plant staff are so angry that they
don't listen to CPE findings. Experience is valuable
in balancing the presentation of difficult findings
and achieving a motivational response. Often, it is
valuable to have one person initiate the presenta-
tion of the findings with the option available for
other team members to support the discussion.
Arguments should be avoided during presentation
of the factors.
It is emphasized that findings, and not recommen-
dations, be presented at the exit meeting. The
CPE, while comprehensive, is conducted over a
short time and is not a detailed engineering study.
Recommendations made without appropriate fol-
low-up could confuse operators and administra-
tors, lead to inappropriate or incorrect actions on
the part of the utility staff, and ultimately result in
improper technical guidance. For example, a rec-
ommendation to set coagulant dosages at a spe-
cific level could be followed literally to the extent
that operations staff set coagulant dosages at the
recommended level and never change them even
though time and highly variable raw water condi-
tions should have resulted in dosage adjustments.
An assessment of the value of follow-up activities
should be discussed at the exit meeting. The
utility may choose to pursue addressing perform-
ance limiting factors on their own. The CPE
evaluators should emphasize the need to compre-
hensively address the factors identified. A piece-
meal approach to address only the design limita-
tions likely would not result in improved perform-
ance if adverse operation and administration
factors continue to exist. It should also be made
clear at the exit meeting that other factors are
likely to surface during the conduct of any follow-
up activities. These factors will also have to be
addressed to achieve the desired performance.
This understanding of the short term CPE evalua-
tion capabilities is often missed by local and regu-
latory officials, and efforts may be developed to
address only the items prioritized during the CPE.
The evaluator should stress that a commitment
must be made to achieve the desired optimized
performance, not to address a "laundry list" of
currently identified problems.
It is important to present all findings at the exit
meeting with utility staff. This approach elimi-
nates surprises when the CPE report is received.
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An ideal conclusion for an exit meeting is that the
utility fully recognizes its responsibility to provide
a high quality finished water and that, provided
with the findings from the CPE, the utility staff are
enthusiastic to pursue achievement of this goal.
4.3.4 CPE Report
At the conclusion of the on-site activities, a CPE
report is prepared. The objective of a CPE report
is to summarize findings and conclusions. Ten to
fifteen typed pages are generally sufficient for the
text of the report. The CPE report should be
available within a month following the on-site
activities to reinforce the need to address factors
limiting optimized performance. An example
report is presented in Appendix G. Typical con-
tents are:
• Introduction
• Facility Information
• Performance Assessment
• Major Unit Process Evaluation
• Performance Limiting Factors
• Assessment of Applicability of a CTA
As a minimum, the CPE report should be distrib-
uted to plant administrators, and they should be
requested to distribute the report to key plant per-
sonnel. Further distribution of the report (e.g., to
regulatory personnel or to the design consultant)
depends on the circumstances of the CPE.
4.4 Case Study
The following case study provides insights on the
conduct of a CPE at an actual water utility. The
state regulatory agency had identified in their
review of monthly monitoring reports that a con-
ventional water treatment plant was routinely vio-
lating the 0.5 NTU limit on finished water turbid-
ity. The state notified the community that they
intended to conduct a CPE to identify the reasons
for non-compliance with current regulatory
requirements.
4.4.7 Facility Information
Facility A serves a community of 10,000 people
and is located in an area with a temperate climate.
The facility was designed to treat 5.0 MGD. Nor-
mally during the year the plant is operated for
periods ranging from 5 to 12 hours each day.
During operation, the facility is always operated at
a flow rate of 5 MGD. A flow schematic of the
facility is shown in Figure 4-9.
The following data were compiled from the com-
pleted data collection forms, as presented in
Appendix F.
Design Flow: 5.0 MGD
Average Daily Flow: 1.2 MGD
Peak Daily Flow: 4.0 MGD
Peak Instantaneous Operating Flow:
5.0 MGD
Figure 4-9. Flow schematic of Plant A.
Sedimentation
Cleanwater Creek
Flash
Mix
'
Flocculation
'
-
I
r
• —
—
Claarwell/Contac
HighS
*• Pumps
&
^ -o-
K>
=ilters
I 1
ervice
'
TO
Distribution
Sludge to Ponds/
Drying Beds
Backwash to
Pond Supernatant
Returned to Plant
-------
Flocculation:
Number Trains: 2
• Type: Mechanical turbines, 3 stages
. Dimensions:
* Length: 15.5 ft
* Width: 15.5 ft
* Depth: 10.0 ft
Sedimentation:
Number Trains: 2
. Type: Conventional rectangular
. Dimensions:
* Length: 90 ft
* Width: 30 ft
* Depth: 12ft
Filtration:
Number: 3
. Type: Dual media (i.e., anthracite, sand),
gravity
• Dimensions:
* Length: 18 ft
* Width: 18 ft
Disinfection:
. Disinfectant: Free chlorine
• Application Point: Clearwell
Number: 1
. Clearwell Dimensions:
* Length: 75 ft
* Width: 75 ft
* Maximum operating level: 20 ft
* Minimum operating level: 14 ft
Baffling factor: 0.1 based on unbaffled
basin
4.4.2 Performance Assessment
The performance assessment, using the most
recent 12 months of data, indicated that the fin-
ished water turbidity was not meeting the regu-
lated quality of <0.5 NTU in 95 percent of the
samples collected each month. In fact, the
95 percent requirement was exceeded in 5 of 12
months, The raw water turbidity averaged
approximately 15 NTU and the settled water tur-
bidity was measured at 4.3 NTU during the CPE.
Routine sampling of settled water was not being
practiced. Field evaluation of one of three filters
during the on-site activities indicated a turbidity
spike of 1 .1 NTU following backwash with a
reduction to 0.6 NTU after one hour of operation.
The results of the performance assessment indi-
cated that optimized performance goals were not
being achieved.
4.4.3 Major Unit Process Evaluation
A performance potential graph (Figure 4-10) was
prepared to assess the capability of Plant A's ma-
jor unit processes. The calculations that were
conducted to complete the graph are shown in the
following four sections.
FIGURE 4-10. Performance potential graph for
Plant A.
Unit Process I
Flocculation<1>
Sedimentation*2'
Filtration Rate*3)
Disinfection!*'
Type 1
i
Type 2
80% of Peak *• J
Type 1
I
Type 2 |
1
S 1
1
Peak Instantaneous Operating
Row . 5.0 MGD
(1) Rated at 20 min (HOT) - 7.6 MGD
(2) Rated at 0.6 gpm/ft2 - 4.7 MGD
(3) Rated at 4.0 gpm/ft2 - 5.6 MGD
(4) Rated at 20 min HOT - 4.2 MGD
4.4.3.1 Flocculation Basin Evaluation
The flocculation basins were rated at a hydraulic
detention time of 20 minutes because the floccula-
tion system has desirable flexibility (i.e., three
stages with each stage equipped with variable
speed flocculators). The plant is also located in a
temperate climate, so the temperature criteria is
< 0.5°C.
61
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1. Basin Volume = 6 basins x 15.5 ft x
IS.Sn x 10 ft x 7.48 gal/ft3
= 107,824 gallons
2. Select 20-minute detention time to determine
peak rated capability.
3. Rated Capability = 107,824 gal/20 minutes
1 MOD
1. Filter Area
= 3 filters x 18 ft x 18 ft
= 972 ft2
= 5,391 gpm x
= 7.8 MGD
694.4 gpm
The 20-minute detention time results in a rated
capability of 7.8 MGD. Therefore, the flocculation
system is rated Type 1 because the 7.8 MGD
exceeds the peak instantaneous plant flow of
5.0 MGD.
4.4.3.2 Sedimentation Basin Evaluation
The sedimentation basins were rated at
0.6 gpm/ft2 surface overflow rate. This mid-range
criteria was selected based on the basin depth of
12 ft and the observed poor performance during
the on-site activities.
1. Basin Surface Area = 2 basins x 90 ft x 30 ft
= 5,400 ft2
2. Select 0.6 gpm/ft2 surface overflow rate to
determine peak rated capability.
3. Rated Capability = 5,400 ft2 x 0.6 gpm/ft2
= 3,240 gpm x 1 MGD
694.4 gpm
= 4.7 MGD
The 0.6 gpm/ft2 overflow rate results in a rated
capability of 4.7 MGD. The sedimentation basins
are rated Type 2 because the 4.7 MGD rating falls
within 80 percent of the 5 MGD peak instantane-
ous operating flow.
4.4.3.3 Filter Evaluation
The filters were rated at 4 gpm/ft2 filtration rate
based on dual-media with adequate backwashing
capability.
2. Select 4 gpm/ft2 to determine peak rated capa-
bility.
3. Rated Capability = 972 ft2 x 4 gpm/ft2
= 3,888 gpm x 1 MGD
694.4 gpm
= 5.S MGD
The 4 gpm/ft2 rate results in a rated capability of
5.6 MGD. The filters were rated Type 1 because
5.6 MGD exceeds the peak instantaneous operat-
ing flow of 5.0 MGD.
4.4.3.4 Disinfection Process Evaluation
The disinfection system was evaluated based on
post-disinfection capability only since prechlorina-
tion was not practiced at Plant A.
1. Determine required Giardia log reduction/
inactivation based on raw water quality.
Select 3.0 log, based on state regulatory
agency requirement.
2. Determine CT based on minimum water tem-
perature and maximum treated water pH.
From plant records select:
Temperature (minimum) = 0.5 ° C
pH (maximum) = 7.5
3. Determine log inactivation required by disinfec-
tion.
Allow 2.5 log reduction because plant is con-
ventional facility in reasonable condition with a
minimum Type 2 rating in previous unit proc-
ess evaluation.
Log inactivation required by disinfection =
3.0 -2.5 = 0.5
4. Determine CT required for 0.5 log inactivation
of Biarfia at pH = 7.5
T = 0.5°C, free chlorine residual = 2.5 mg/L
From tables in Appendix D, CT =
50.5 mg/L-min
82
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5. Determine required contact time based on
maximum free chlorine residual that can be
maintained.
Required contact time = 50.5 mg/L-min
2 5 mg/L
= 20 min
6. Determine effective clearwell (contact basin)
volume required to calculate peak rated
capacity.
Effective volume * = 75 ft x 75 ft x
14 ft x 0.1 x 7.48 gal/ft3
= 58,905 gallons
*Basin is unbaffled so use T10/T factor of 0.1.
Use 14' minimum operating depth.
7. Determine rated capability:
58.905 gal
Rated
Capability = 2Q mjn
= 2,945 gpm
= 4.2 MGD
Y 1MGD
694.4 gpm
The 20 minute HOT results in a rated capa-
bility of 4.2 MGD. The disinfection system
was rated Type 2 because 4.2 MGD falls
within 80 percent of the peak instantaneous
plant flow of 5.0 MGD.
Based on the above calculations, a performance
potential graph was prepared. The performance
potential graph for Plant A is shown in Fig-
ure 4-I 0. As shown, flocculation and filtration
were rated Type 1 because their rated capabilities
exceeded the peak instantaneous operating flow
rate of 5.0 MGD. Sedimentation and post-
disinfection unit process were rated Type 2
because rated capacity was within 80% of the
It is noted that the option to operate the facility for
a longer period of time to lower the peak instanta-
age daily flow rate on an annual basis is 1.2 MGD.
If the plant were operated for 8 hours per day at
flow rate below the projected capability of all of
the major unit processes. For peak demand days,
longer periods of operation. This option offers the
capability to avoid major construction and still pur-
ties.
4.4.4 Performance Limiting Factors
The following performance limiting factors were
"A" or "B."
was also conducted, as indicated by the number
/. Application of Concepts and Testing to Proc-
ess Control - Operation (A)
• The plant operators had established no
process control program to make deci-
sions regarding plant flow rate, coagulant
dose and filter operation.
• Coagulant dosages had not been estab-
lished based on jar tests or other means
and were typically maintained at a con-
stant setting despite raw water quality
variations.
• Filters were started dirty on a routine
basis and the plant was operated at
maximum capacity when a much lower
rate was possible.
• Filter effluent turbidities exceeded regula-
tory requirements for extended periods
following backwash of a filter.
• The operator's lack of awareness of the
existence or impact of these spikes dem-
onstrated a limited understanding of water
treatment technology and the importance
of producing high quality treated water on
a continuous basis.
2. Process Control Testing - Operation (A)
• The only process control testing that was
conducted was turbidity on daily grab
samples of raw water and treated water
from the clearwell and chlorine residual on
treated water after the high service
pumps.
• No process control testing was done to
establish coagulant dosages or optimized
sedimentation and filtration unit process
performance.
63
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Plant Coverage - Administration (A)
Plant operators were only allowed enough
time to be at the plant to fill the reservoir,
approximately six hours each day.
On occasion, the alum feed line would
plug and go unnoticed, resulting in peri-
ods of poor treated water quality.
• The operators were expected to conduct
other activities, such as monitoring the
city swimming pool, assisting wastewater
treatment plant operators, and assisting
street maintenance crews during summer
months.
plant flow can be reduced and operator coverage
increased, it appears that the utility would be able
to achieve improved performance through imple-
mentation of a follow-up CTA. These conditions
would require approval by the City Council before
a CTA could be initiated. Documentation of
improvement in finished water turbidity, including
reduction of spikes after dirty filter start-up and
backwashing, should result from CTA efforts.
Additionally, maintaining settled water turbidity at
< 2 NTU on a continuous basis would be the
expected result from a CTA. These improvements
to optimized performance will enhance the treat-
ment barriers that this facility provides and, thus,
enhance public health protection.
4. Disinfection - Design (B)
Operation of the plant at maximum flow
rate does not allow sufficient contact time
for disinfection. However, operation of
the plant at or below 4.2 MGD allows the
disinfection unit process to be in compli-
ance with existing regulations.
5. Sedimentation - Design (B)
. The sedimentation basin was not pro-
jected to be capable of achieving opti-
mized performance criteria at flows above
4.7 MGD. Reducing the flow would allow
the basin to perform adequately during
most periods of the year.
6. Sample Taps - Design (B)
Sample taps do not exist to allow samples
to be obtained from the individual filters.
This prevents the plant staff from obtain-
ing needed information to optimize indi-
vidual filter performance.
4.4.5 Assessing Applicability of a CTA
The most serious of the performance limiting fac-
tors identified for Plant A were process control-
oriented. The evaluation of major unit processes
resulted in a Type 2 rating at the present peak
instantaneous operating flow. However, it was
determined that the rating could be upgraded to
Type 1 if the plant peak instantaneous operating
flow rate could be reduced by operating for longer
periods of time each day. This adjustment will
require addressing the plant coverage factor by
convincing administrators to allow operators to
spend additional time at the treatment facility. If
4.4.6 CPE Results
The success of conducting CPE activities can be
measured by plant administrators selecting a fol-
low-up approach and implementing activities to
achieve the required performance from their water
treatment facility. If definite follow-up activities
are not initiated within a reasonable time frame,
the objectives of conducting a CPE have not been
achieved. Ideally, follow-up activities must com-
prehensively address the combination of factors
identified (e.g., implement a CTA) and should not
be implemented in a piecemeal approach. In the
previous example, plant administrators decided to
hire a third party to implement a CTA. The CTA
addressed the identified factors and resulted in the
existing plant achieving optimized performance
goals without major capital improvements.
4.5 References
1. Bender, J.H., R.C. Renner, B.A. Hegg, E.M.
Bissonette, and R. Lieberman. 1995. "Part-
nership for Safe Water Voluntary Water
Treatment Plant Performance Improvement
Program Self-Assessment Procedures. "
USEPA, AWWA, AWWARF, Association of
Metropolitan Water Agencies, Association of
State Drinking Water Administrators, and
National Association of Water Companies.
2. Eastern Research Group, Inc. 1992. Water
Advisor Utilizing the CCP Approach (Expert
System). USEPA Work Assignment No. 7391-
55. Eastern Research Group, Inc., Arlington,
MA.
64
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3. Renner, R.C., B.A. Hegg, J.H. Bender, and
E.M. Bissonette. February 1991. Handbook -
Optimizing Water Treatment Plant Performance
Usina the Composite Correction Proaram. EPA
625/9-91 7027. USEPA, Cincinnati, OH.
American Society of Civil Engineers and
American Water Works Association. 1990.
Water Treatment Plant Desian. McGraw-Hill,
2nd ed.
5. James M. Montgomery Consulting Engineers,
Inc. 1985. Water Treatment Principles and
Desian. John Wiley & Sons, Inc.
6. Sanks, R.L., ed.. 1978. Water Treatment
Plant Desian for the Practicing Enaineer. Ann
Arbor Science Publishers, Kent, England.
Renner, R.C., B.A. Hegg, and J.H. Bender.
March 1990. EPA Summary Report: Opti-
mizina Water Treatment Plant Performance
With the Composite Correction Prooram. EPA
625/8-90/01 7, USEPA Center for Environ-
mental Research Information, Cincinnati, OH.
8. "Surface Water Treatment Rule", from Federal
Register, Vol. 54, No. 124, U.S. Environ-
mental Protection Agency, 40 CFR, Parts 141
and 142, Rules and Regulations, Filtra-
tion/Disinfection (June 1989).
9. USEPA. 1989. Guidance Manual for Compli-
ance With the Filtration and Disinfection
Reauirements for Public Water Systems Using
Surface Water Sources. NTIS No. PB
90148016. USEPA, Washington, DC.
10. Regli, S. June 1990. "How's and Why's of
CTs." Presented at AWWA Annual Confer-
ence, Cincinnati, OH.
11. Cleasby, J.L., M.M. Williamson, and E.R.
Baumann. 1963. "Effect of Filtration Rate
Changes on Quality." Journal AWWA, 55:869-
878.
12. Cleasby, J.L., A.H. Dharmarajah, G.L. Sindt,
and E.R. Baumann. September 1989. Desian
and Operation Guidelines for Optimization of
the High Rate Filtration Process: Plant Survey
Results. AWWA Research Foundation and
AWWA, Denver, CO.
65
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Chapter 5
Comprehensive Technical Assistance
5.1 Objective
The objective of conducting Comprehensive Tech-
nical Assistance (CTA) activities is to achieve and
sustain optimized performance goals, as was
described in Chapter 2. Given this objective, the
results of a successful CTA can be easily depicted
in graphical form. Results from an actual CTA are
presented in Figure 5-I. As shown, plant per-
formance was inconsistent as depicted by the
variations in finished water turbidity. However,
after CTA activities had been implemented (April
1997) the treated water quality gradually improved
to a level that has been consistently less than
0.1 NTU. It is noted that other parameters, such
as improved operator capability, cost savings, and
improved plant capacity are often associated with
the conduct of a CTA, but the true measure of
success is the ability to achieve optimized per-
formance goals and demonstrate the capability to
meet these goals long-term under changing raw
water quality conditions. It is recommended that
CTA results be presented graphically to indicate
that the primary objective has been achieved.
An additional objective of a CTA is to achieve opti-
mized performance from an existing water treat-
ment facility (i.e., avoid, if possible, major modifi-
cations). If the results of a Comprehensive Per-
formance Evaluation (CPE) indicate a Type 1 plant
(see Figure 4-3), then existing major unit proc-
esses have been assessed to be adequate to meet
optimized treatment requirements at current plant
loading rates. For these facilities, the CTA can
focus on systematically addressing identified per-
formance limiting factors to achieve optimized per-
formance goals.
For Type 2 plants, some or all of the major unit
processes have been determined to be marginal.
Improved performance is likely through the use of
a CTA; however, the plant may or may not meet
optimized performance goals without major facility
modifications. For these plants, the CTA focuses
on obtaining optimum capability of existing facili-
ties. If the CTA does not achieve the desired fin-
ished water quality, unit process deficiencies will
be clearly identified and plant administrators can
be confident in pursuing the indicated facility
modifications.
Figure 5-1. CTA results showing finished water quality improvements.
67
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For Type 3 plants, major unit processes have been
determined to be inadequate to meet performance
objectives. For these facilities, major construction
is indicated and a comprehensive engineering
study that focuses on alternatives to address the
indicated construction needs is warranted. The
study should also look at long term water needs,
raw water source or treatment alternatives, and
financing mechanisms.
If an existing Type 3 plant has performance prob-
lems with the potential to cause serious public
health risk, officials may want to try to address
any identified limitations, in addition to the design
factors, to improve plant performance. In these
cases, activities similar to a CTA could be imple-
mented to obtain the best performance possible
with the existing facilities, realizing that optimum
performance would not be achieved. Additionally,
administrative actions such as a boil order or
water restrictions may have to be initiated by
regulators until improvements and/or construction
can be completed for Type 3 facilities.
5.2 Conducting CTAs
5.2. I Overview
The CTA was developed as a methodology to
address the unique combination of factors that
limit an individual facility's performance through
use of a consistent format that could be applied at
multiple utilities. This foundation for the CTA
necessarily required a flexible approach. Concepts
that define the general CTA approach are further
discussed.
Implementation of a CTA is guided by an unbiased
third party who is in a position to pursue correc-
tion of factors in all areas such as addressing
politically sensitive administrative or operational
limitations. This person, called the CTA facilitator,
initiates and supports all of the CTA activities.
The CTA facilitator uses a priority setting model as
a guide to address the unique combination of fac-
tors that have been identified in a CPE. Based on
the priorities indicated by this model, a systematic
long term approach is used to transfer priority set-
ting and problem solving skills to utility personnel.
The priority setting model is illustrated graphically
in Figure 5-2.
The first step in implementation of a CTA is estab-
lishing the optimized performance goals that will
be the objectives to achieve during the conduct of
the CTA. Since these goals exceed regulated
requirements, the plant administration has to
embrace achieving this level of performance from
a public health perspective. For example, adminis-
trators must be aware that even momentary
excursions in water quality must be avoided to
prevent Biardia and Cryptosporidium or other
pathogenic organisms from passing through the
treatment plant and into the distribution system.
To this end, all unit processes must be performing
at high levels on a continuous basis, thus provid-
ing a "multiple barrier" to passage of pathogenic
organisms through the treatment plant. Ulti-
mately, administrators must adopt the concept of
optimized performance goals and be willing to
emphasize the importance of achieving these goals
within the framework of the CTA.
Figure 5-2. CTA priority setting model.
Optimized Performance Goals
Operation (Process Control)
k
\.
\
r
Capable Rant
Administrative
Design
Maintenance
When the performance objectives are established,
the focus turns to operation (i.e., process control)
activities. Implementing process control is the key
to achieving optimized performance goals with a
capable facility. Administration, design and main-
tenance are necessary to support a capable plant.
Any limitations in these areas hinder the success
of the process control efforts. For example, if fil-
tered water turbidity cannot be consistently main-
tained at optimized levels because operating staff
is not at the plant to make chemical feed adjust-
ments in response to changing raw water quality,
then improved performance will require more staff
coverage. In this case, identified limitations in
making chemical feed adjustments established the
priority for improving staff coverage (i.e., an
administrative policy). Additional staff coverage
would alleviate the identified deficiency (i.e., sup-
port a capable plant) and allow process adjust-
ments to be made so that progress toward the
68
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optimized performance goals could be continued.
In this manner, factors can be prioritized and
addressed, ensuring efficient pursuit of the opti-
mized performance goals.
The results of the CPE (Chapter 4) provide the ini-
tial prioritized list of performance limiting factors
impacting an individual facility. The CTA facilita-
tor utilizes these factors, coupled with the priority
setting model, to establish the direction for the
CTA. It is important to note that a CTA is a
dynamic process, and the facilitator will have to
constantly readjust priorities as the events unfold.
The model can be used repetitively to assist in the
prioritization of CTA activities.
A systematic long term process is used to transfer
priority setting and problem solving skills to the
utility personnel during a CTA. Typically, 6 to 18
months are required to implement a CTA. This
long time period is necessary for several reasons:
Time necessary to identify and develop a local
champion or champions. Since the CTA facili-
tator is off-site, one or more personnel that
can implement the CTA activities need to be
identified. These persons are called champi-
ons since they are the focal point for CTA
implementation. They are designated as the
person at the plant responsible to understand
the implementation of the CTA and to assist
the plant staff with CTA activities on a day-to-
day basis. This person is also the key contact
for communications with the CTA facilitator
and the local personnel. The champion is also
the focal point for the transfer of priority
setting and problem solving skills. The cham-
pion will ultimately be responsible for transfer
of these skills to the other utility personnel.
This transfer is essential to ensure the conti-
nuity of water quality improvements after the
facilitator is gone. Ideally, the champion
would be the superintendent or lead operator.
. Greater effectiveness of repetitive training
techniques. Operator and administrator train-
ing should be conducted under a variety of
actual operating conditions (e.g., seasonal
water quality or demand changes). This
approach allows development of observation,
interpretation, and implementation skills nec-
essary to maintain desired finished water
quality during periods of variable raw water
quality.
Time required to make minor facility modifica-
tions. For changes requiring financial expendi-
tures, a multiple step approach is typically
required to gain administrative (e.g., City
Council) approval. First, the need for minor
modifications to support a capable facility
must be demonstrated. Then, council/
administrators must be shown the need and
ultimately convinced to approve the funds
necessary for the modifications, This process
results in several months before the identified
modification is implemented and operational.
Time required to make administrative changes.
Administrative factors can prolong CTA
efforts. For example, if the utility rate struc-
ture is inadequate to support plant perform-
ance, extensive time can be spent facilitating
the required changes in the rate structure.
Communication barriers between "downtown"
and the plant or among staff members may
have to be addressed before progress can be
made on improved performance. If the staff is
not capable, changes in personnel may be
required for the CTA to be successful. The
personnel policies and union contracts under
which the utility must operate may dictate the
length of time these types of changes could
take.
Time required for identification and elimination
of any additional performance limiting factors
that may be found during the CCP. It is impor-
tant to note that additional performance limit-
ing factors, not identified during the short
duration of the CPE, often become apparent
during conduct of the CTA. These additional
limitations must also be removed in order to
achieve the desired level of performance.
5.2.2 Implementation
Experience has shown that no single approach to
implementing a CTA can address the unique com-
bination of factors at every water treatment plant.
However, a systematic approach has been devel-
oped and specific tools have been used to increase
the effectiveness of CTA activities. The approach
requires involvement of key personnel and estab-
lishes the framework within which the CTA activi-
ties are conducted. Key personnel for the imple-
mentation of the CTA are the CTA facilitator and
69
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the utility champions. The framework for con-
ducting the activities includes site visits, commu-
nication events, and data and records review con-
ducted over a sufficient period of time (e.g., 6 to
18 months),
The tools utilized for conducting CTAs have been
developed to enhance the transfer of capability to
utility administrators and staff. Actual implemen-
tation of each CTA is site-specific, and the combi-
nation of tools used is at the discretion of the CTA
facilitator. Additional approaches to addressing
performance limiting factors exist,, and a creative
facilitator may choose other options,
Implementation of a successful CTA requires that
the CTA facilitator constantly adjust the priorities
and implementation techniques to match the
facility and personnel capabilities at the unique
site. The bottom line is that optimized perform-
ance goals, that can be graphically depicted, need
to be achieved as a result of the CTA efforts (see
Fioure 5-I). Components of CTA implementation
are further described.
5.2.2.1 Approach
CTA Facilitator
The CTA facilitator is a key person in the imple-
mentation of CTA activities and must possess a
variety of skills due to the dynamic nature of the
process. Desired skills include a comprehensive
understanding of water treatment unit processes
and operations and strong capabilities in leader-
ship, personnel motivation, priority setting, and
problem solving.
Comprehensive understanding of water treatment
unit processes and operations is necessary
because of the broad range of unit processes
equipment and chemicals utilized. For example,
numerous sedimentation devices exist such as
spiral flow, reactor type, lamella plate, tube set-
tlers, pulsators and solids contact units. Addition-
ally, multiple possibilities exist in terms of types,
combinations and dosages of coagulant, flocculant
and filter aid chemicals.
Operations capability is necessary to understand
the continually changing and sometimes conflicting
requirements associated with water treatment.
Optimization for particulate removal ultimately has
to be coordinated with control of other regulated
parameters such as disinfection by-products or
lead and copper. In addition, those responsible for
implementing a CTA must have sufficient process
control capability to establish an appropriate
approach that is compatible with the personnel
capabilities available at the utility.
A CTA facilitator must often address improved
operation, improved maintenance, and minor
design modifications with personnel already
responsible for these water treatment functions,
A "worst case situation" is one in which the plant
staff is trying to prove that "the facilitator can't
make it work either." The CTA facilitator must be
able to create an environment to maintain commu-
nications and enthusiasm and to allow all parties
involved to focus on the common goal of achiev-
ing optimized plant performance. Ultimately, the
CTA facilitator must transfer priority setting and
problem solving skills to the utility staff. The
objective here is to leave the utility with the nec-
essary skills after the facilitator leaves so that the
performance goals can be met long term. To
accomplish this transfer, the facilitator must create
situations for local personnel to "self discover"
solutions to ongoing optimization challenges so
that they have the knowledge and confidence to
make all necessary changes. In almost all cases
the facilitator must avoid assuming the role of
troubleshooter or the person with all of the
answers. Each situation has to be evaluated for
its learning potential for the staff.
A CTA facilitator must be able to conduct training
in both formal and on-the-job situations. Training
capabilities must also be developed so they are
effective with both operating as well as adminis-
trative personnel. When addressing process con-
trol limitations, training must be geared to the
specific capabilities of the process control decision
makers. Some may be inexperienced; others may
have considerable experience and credentials.
"Administrative" training is often a matter of
clearly providing information to justify or support
CTA objectives or activities. Although many
administrators are competent, some may not know
what to expect from their facilities or what their
facilities require in terms of staffing, minor modifi-
cations, or specific funding needs.
CTA facilitators can be consultants, state and fed-
eral regulatory personnel, or utility employees. For
consultants, the emphasis of optimizing the
"existing facility" without major construction must
be maintained. A substantial construction cost
can be incurred if an inexperienced facilitator is
not able to bring a capable water treatment plant
70
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to the desired level of performance. For example,
a consultant, involved primarily with facility
design, may not have the operational experience to
utilize the capability of existing unit processes to
their fullest extent and may be biased toward
designing and constructing new processes.
If utility personnel try to fill the role as CTA facili-
tator, they should recognize that some inherent
problems may exist. The individuals implementing
the CTA, for example, often find it difficult to pro-
vide an unbiased assessment of the area in which
they normally work (i.e., operations personnel tend
to look at design and administration as problem
areas; administrators typically feel the operations
personnel should be able to do better with existing
resources). These biases should be recognized,
and they must be continually challenged by utility
personnel who assume the role of CTA facilitator.
Individuals who routinely work with water utilities
to improve water treatment plant performance will
likely be the best qualified CTA facilitators. These
people are typically engineers or operators who
have gained experience in correcting deficiencies
at plants of various types and sizes. CTA facilita-
tors that have experience in a variety of plants
have a definite advantage in their ability to recog-
nize and correct true causes of limited perform-
ance.
On-Site CTA Champion
In addition to the capabilities of the CTA facilita-
tor, it is necessary to have one or several utility
personnel who "champion" the objectives and
implementation of the CTA process. The cham-
pion is the person who assumes the day-to-day
responsibilities of pursuing the implementation of
the established priorities. This person is also
responsible for the transfer of problem solving
skills learned from the CTA facilitator to the rest of
the staff.
Identification of the champion is a key step in the
success of the CTA. Ideally, the superintendent or
lead operator is the person that would fill the
champion role. However, many times these indi-
viduals may be part of the limitation to achieving
optimized performance because they tend to stick
to the old ways of conducting business. New
operators or laboratory personnel often offer the
greatest potential for the role as champion. To
resolve some of the issues with the selection of
these "junior" personnel, a champion team con-
sisting of the selected personnel and the personnel
that normally would assume the role (e.g., the
superintendent) can be selected.
Ideally the role of the champion is formally identi-
fied during the CTA activities. In other cases,
however, it may be necessary to use an informal
approach where the champion is only recognized
by the CTA facilitator. For example, in some
cases the champion may not be the typical person,
based on the "chain of command." In these cases
the use of a junior person to assist the supervisor
or superintendent in the actual implementation
may be the only option available to ensure pro-
gress on CTA activities. This is a delicate situa-
tion for the facilitator, and extra effort is required
to maintain open communications and acceptance
for project activities. In any event, the closer the
characteristics of the champion are to those out-
lined for the CTA facilitator, the easier the imple-
mentation of the CTA will be.
CTA Framework
A consistent framework has been developed to
support the implementation of a CTA. The
framework consists of on-site involvement (e.g.,
site visits) interspersed with off-site activities
(e.g., communication events such as phone/fax/
e-mail and data and guidelines review). A graphi-
cal illustration of the CTA framework is shown in
Figure 5-3.
• Site visits are used by the facilitator to verify
or clarify plant status, establish optimization
performance goals, initiate major process con-
trol changes, test completed facility modifica-
tions, provide on-site plant or administrative
training, and report progress to administrators
and utility staff. Dates for site visits cannot be
established at specific intervals and must be
scheduled based on plant status (e.g., process
upsets), training requirements, communica-
tions challenges, etc. As shown in Figure 5-3,
site visits and communication events typically
taper off as the CTA progresses. This is in
line with the transfer of skills to the plant staff
that occurs throughout the CTA. The number
of site visits required by a CTA facilitator is
dependent on plant size and on the specific
performance limiting factors. For example,
some administrative (e.g., staffing and rate
changes) and minor design modifications could
significantly increase the number of site visits
required to complete a CTA. Typically, the
71
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Figure 5-3. Schematic of CTA framework.
1234567
10 11 12
Site Visits
Communication:
Phone, Fax, E-Mai
Data and
Correspondence
Review
Reporting
Activities
I
«••
0 0
o
keo •
0 0
o«
e o
I
oo
O O
o
Months of Involvement
initial site visit is conducted over three to four
days and intermediate site visits are conducted
over two to three days. CTA accomplish-
ments and proposed future activities are pre-
sented to plant and administrative personnel at
an exit meeting at the conclusion of each site
visit.
. Communication events such as telephone
calls, faxes and e-mail are used to routinely
assess CTA progress. Communication activi-
ties are normally conducted with the on-site
CTA champion. Routine contact is used to
train and encourage plant personnel to pursue
data collection and interpretation, encourage
progress on prioritized activities, and provide
feedback on special studies and guideline
development. The CTA facilitator should
always summarize important points, describe
decisions that have been reached, and identify
actions to be taken. Further, both the CTA
facilitator and plant personnel should maintain
written phone logs. It is noted that communi-
cation events have limited ability to address all
identified factors. As such, the CTA facilitator
should always monitor the progress being
accomplished in the effectiveness of the com-
munication events to assess the need for a site
visit.
. Data and correspondence review are activities
where the CTA facilitator reviews the informa-
tion provided routinely by the utility. A format
for submittal of weekly performance data is
established during the initial site visit. This
information is provided in hard copy or elec-
tronically by the utility. Results of special
studies or draft operational guidelines are also
submitted to the CTA facilitator for review.
Review and feedback by the CTA facilitator are
key to demonstrate the importance of efforts
by the utility personnel. Findings from data
and records review are related to the staff by
communications events. The routine feedback
enhances the data development and interpreta-
tion skills of the utility staff.
Reporting activities are used to document pro-
gress and to establish future direction. Short
letter reports are typically prepared at the con-
clusion of each site visit. These reports can
be used to keep interested third parties (e.g.,
regulatory personnel) informed and to maintain
a record of CTA progress and events. They
also provide the basis for the final CTA report,
Short reports or summaries can also be devel-
oped to justify minor facility upgrades or
changes in plant coverage or staffing. A final
CTA report is typically prepared for delivery at
the last site visit. The report should be brief
(e.g., eight to twelve pages are typically suffi-
cient for the text of the report). Graphs docu-
menting the improvement in plant performance
should be presented. If other benefits were
achieved these should also be documented.
Typical contents are:
. Introduction:
* Reasons for conducting the CTA.
. CPE Results:
* Briefly summarize pertinent informa-
tion from the CPE report.
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. CTA Significant Events:
* Chronological summary of activities
conducted.
* Include special study results.
. CTA Results:
* Graph of plant performance plus
other benefits.
Conclusions:
* Efforts required to maintain improved
performance.
. Appendices:
* Compilation of site specific guidelines
developed by the plant staff.
5.2.2.2 Tools
Contingency Plans
Contingency plans should be prepared for facilities
producing finished water quality that is not meet-
ing current regulated requirements and for possible
instances when finished water degrades during
implementation of changes during the CTA. The
contingency plan should include actions such as
reducing plant flow rate to improve performance,
shutting down the plant, initiating a voluntary
public notification, and initiating a voluntary boil
order. If plant finished water exceeds a regulated
maximum contaminant level (MCL), the State
regulatory agency should be immediately informed,
and public notification procedures mandated by
the Public Notification Regulation Rule (1) should
be followed. To minimize the chance of producing
unacceptable finished water while conducting a
CTA, all experimentation with chemical doses and
different coagulant products should be done on a
bench scale (e.g., jar test) before implementing
changes on a full scale basis. Full scale experi-
mentation can be done on an isolated treatment
train or during low demand conditions that would
allow "dumping" of improperly treated water.
Action Plans
Action plans can be utilized to ensure progressive
implementation of performance improvement
activities. The action plan summarizes items to be
completed, including the name of the person that
is assigned a particular task and the projected due
date. The plan is normally developed during the
CTA site visits and distributed by the CTA facilita-
tor. The plan should identify tasks that are clear
to the person responsible and within their area of
control. The person should have been involved in
the development of the action item and should
have agreed to the assignment and the due date.
The action plan is provided to administrators and
plant personnel after site visits or communication
events. Communication events are used to
encourage and monitor progress on the assigned
action items. An example format for an "Action"
plan is shown in Figure 5-4.
Figure 5-4. Example action plan.
Item
1
2
3
Action
Develop calibration curve
for polymer feed pump.
Draft special study
procedure to evaluate use
of a flocculant aid to
improve sedimentation
basin performance.
Process control:
a. Develop daily data
collection sheet.
b. Develop routine
sampling program.
c. Draft guideline for jar
testing.
Person
Responsible
Jon
Bob
Larry
Eric
Rick
Date
Due
4/4
5/1
4117
4/24
4/28
Special Studies
Special studies can be used to evaluate and opti-
mize unit processes, to modify plant process con-
trol activities, or to justify administrative or design
changes necessary to improve plant performance.
They are a structured, systematic approach for
assessing and documenting plant optimization
activities. The format for development of a special
study is shown in Figure 5-5. The major compo-
nents include the special study topic, hypothesis,
approach, duration of the study, expected results,
documentation/conclusions, and implementation
plan. The hypothesis should have a focused
scope and should clearly define the objective of
the special study. The approach should provide
detailed information on how the study is to be
conducted including: when and where samples
are to be collected, what analyses are to be con-
ducted, and which specific equipment or proc-
esses will be used. The approach should be
73
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developed in conjunction with the plant staff to
obtain staff commitment and to address any chal-
lenges to implementation that may exist prior to
initiating the study. Expected results ensure that
measures of success or failure are discussed prior
to implementation. It is important that the study
conclusions be documented. Ideally, data should
be developed using graphs, figures and tables.
This helps to clarify the findings for presentation
to interested parties (e.g., plant staff, administra-
tors, regulators). Special study findings serve as a
basis for continuing or initiating a change in plant
operation, design, maintenance or administration.
An implementation plan in conjunction with con-
clusions identifies the procedural changes and
support required to utilize special study results. If
all of the steps are followed, the special study
approach ensures involvement by the plant staff,
serves as a basis for ongoing training, and
increases confidence in plant capabilities. An
example special study is presented in Appendix I.
Ooerational Guidelines
Operational guidelines can be used to formalize
activities that are essential to ensure consistent
plant performance. Examples of guidelines that
can be developed include: jar testing, polymer
dilution preparation, polymer and coagulant feed
calculations, filter backwashing, chemical feeder
calibration, sampling locations and data recording.
The CTA facilitator may provide examples, but
guidelines should be developed by the plant staff.
Through staff participation, operator training is
enhanced and operator familiarity with equipment
manuals is achieved. Additionally, communication
among operators and shifts is encouraged in the
preparation of guidelines. The guidelines should be
prepared using word processing software and
should be compiled in a three-ring binder so that
they can be easily modified as optimization
practices are enhanced. An example guideline is
presented in Appendix J.
Data Collection and Interpretation
Data collection and interpretation activities are
used to formalize the recording of results of proc-
ess control testing that is initiated. Typically, a
daily sheet is used to record operational data such
as lab test results, flow data, and chemical use.
These data are transferred to monthly sheets that
are used to report necessary information to the
regulatory agency and to serve as a historic record
for plant operation. Examples of daily and
monthly process control sheets are presented in
Appendix K. Graphs or trend charts can be used
to enhance the interpretation of process monitor-
ing results. The data developed can be plotted
over long periods to show seasonal trends and
changes in water demand or over shorter periods
to show instantaneous performance. Examples of
data development over a several month period are
shown in Figure 5-1. A short term trend chart
showing raw, settled and filtered water turbidities
over a one-day period is depicted in Figure 5-6.
During this period no change in coagulant dose
was initiated, despite the change in raw water tur-
bidity. As a result, settled water and finished
water quality deteriorated several hours after the
raw water turbidity increased. Without the use of
a trend chart this correlation would be difficult to
observe.
Figure 5-5. Special study format.
Special Study Topic: Identify name of the special study
and briefly describe why the study is being conducted
(i.e., one to two sentences).
Hypothesis:
Focused scope. Try to show definite cause/effect
relationship.
Approach:
Detailed information on conducting study. Involve
plant staff in development.
Duration of Study:
Important to define limits of the study since "extra
work" is typically required.
Expected Results:
Projection of results focuses attention on interim
measurements and defines success or limitations of
effort.
Conclusions:
Documented impact of study allows the effort to be
used as a training tool for all interested parties. Allows
credit to be given for trying an approach.
Implementation:
Identifies changes or justifies current operating
procedures. Formalizes demonstrated
mechanisms to optimize plant performance.
74
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Figure 5-6. Short term trend chart showing relationship of raw, settled and filtered water turbidities.
a 12
Time (hrs)
16
20
Priority Settina Tools
The CTA facilitator uses the priority setting model
(i.e., Figure 5-2) to aid in establishing priorities for
implementing a CTA. Awareness of this model
can be provided to utility personnel to aid them in
setting routine priorities for utility activities.
Another method that is useful for utility personnel
to aid in developing their priority setting skills is
the nominal group process. This mechanism uses
a facilitator (e.g., the CTA facilitator initially and
the utility champion or other staff as the CTA pro-
gresses) to solicit input from plant personnel dur-
ing a formal meeting by asking an open-ended
question concerning optimization activities. A
question such as "What concerns, activities, or
modifications, can we address to continue to pur-
sue optimization performance goals at our utility?"
can be asked to start the discussion. Participants
are given time to develop ideas and the facilitator
then solicits responses one at a time from each
person in a round-robin fashion. After all ideas are
documented (e.g., on a flip chart or chalk board)
the ideas are discussed for clarity and overlap.
The participants then priority vote on the issues
(e.g., vote for the top five issues, allowing five
points for the top issue, four for the second issue,
etc.). Topics are prioritized by the number of
votes that they get, and ties are differentiated by
the number of points. Based on the combined
results of all of the voting, the highest priority
issues are identified. These issues are discussed,
and action steps are identified and placed on an
action list. Example results from a priority setting
activity are shown in Figure 5-7.
The nominal group process encourages involve-
ment of all parties and provides significant training
during the open discussion of prioritized topics.
The CTA facilitator can interrupt the discussions if
technical inaccuracies exist; but, for the most part,
the facilitator should try to maintain a neutral role.
It is important to note, however, that the nominal
group process is only effective after the CTA is
underway and the initial key priorities have been
implemented. After the initial efforts, the utility
personnel are more aware of the purpose of the
CTA and better equipped to contribute meaningful
suggestions concerning optimization activities. It
is up to the CTA facilitator to ascertain when
utility personnel are able to effectively utilize this
tool.
Topic Development Sheets
Topic development sheets (see Figure 5-8) can be
used to develop problem solving skills in utility
personnel. In utilizing the topic development
sheet, the issue should be clearly defined. An
ideal starting point would be a prioritized issue
developed from the nominal group process. The
CTA facilitator, initially, and utility champion, as
the CTA progresses, would lead the discussion on
using the topic development sheet format.
75
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Figure 5-7. Example priority settinq. results from
CTA site visit activity.
Question: What concerns, activities or modifications can
be addressed to continue to pursue optimization goals at
your utility?
List of Responses:
1. Post backwash turbidity spikes
2. Retention of trained staff
3. End point for CTA project
4. Eliminate washwater return
5. Drought impact (color, taste and odor, rationing)
6. Flow indicators on chemical feeders
7. Reconsider particle counter capability
8. Recognition for utility staff by regulatory agency
9. Recent budget constraints
10. Public relations on optimization efforts
1 1. Maintaining optimization approach
Prioritized Topics:
Rank Item
1 Flow indicators on chemical
feeders
2 Post backwash turbidity spikes
3 Retention of trained staff
4 End point for CTA project
5 Maintaining optimization
approach
6 Recognition for utility staff
Votes
6
6
5
4
3
3
Points
24
23
17
7
10
6
Figure 5-8, provides a section listing obstacles.
Typically, it is easier for participants to discuss the
reasons why an idea will not work. After the
obstacles are presented, the facilitator should
focus the group on possible solutions. The facilita-
tor should have the group pursue a solution for
each obstacle. While the discussion occurs, the
benefits for making the change can be listed in the
benefits section of the sheet. The solutions
should be converted to action steps and docu-
mented on the sheet. The action steps should be
subsequently transferred to the optimization action
plan.
Use of the topic development sheet is effective in
enhancing the problem solving skills of utility per-
sonnel. The tool allows obstacles to be presented
but requires that solutions and action steps also be
developed. Use of the topic development sheet
and the associated activity also enhances commu-
nication skills among the staff.
Figure 5-8. Example topic development sheet.
TOPIC DEVELOPMENT SHEET
Topic/Issue:
Benefits:
Possible Obstacles:
Possible Solutions:
Action Steps: •
* ransfer to an Action Plan.
Internal Support
The CTA facilitator must ensure that internal
communication to maintain support for the CTA
occurs at all levels of the organization. This is
typically done through routine meetings (e.g.,
during site visits) or with summary letters and
communication events. Internal support is key to
develop during the conduct of a CTA and can be
useful in accomplishing desired changes. Typi-
cally, a CTA introduces a "new way of doing busi-
ness" to the water utility. This new approach is
not always embraced by the existing personnel.
Support from the personnel department or the
administrative staff can be utilized in establishing
the "acceptable behavior" required of the utility
staff to support the CTA objectives. For example,
the CTA facilitator and utility champion may have
clearly defined a new sampling procedure to
support the optimization efforts. If a staff member
will not comply with the approach or continues to
resist the change, administrative pressure can be
76
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solicited if internal support for project activities
has been maintained.
What-lf Scenarios
Many facilities have very stable raw water sources
and as such are not challenged with variations that
test the capability of facilities and personnel to
respond and maintain optimized performance
goals. In some facilities this is true even if the
duration of the CTA is over a period of a year or
greater. In these facilities, factors relating to reli-
ability and complacency often need to be
addressed. The CTA facilitator can create "what-if
scenarios" for the utility personnel to address.
Development of these scenarios may be the only
opportunity during the conduct of the CTA to pre-
pare local personnel for challenging situations.
"What-if scenarios" should only be utilized after
the plant staff have gained experience and confi-
dence from CTA training activities.
5.2.2.3 Correcting Performance Limiting
Factors
A major emphasis of a CTA is addressing factors
identified as limiting performance in the CPE phase
as well as additional limiting factors that may be
identified during the CTA. Correcting these fac-
tors provides a capable plant and allows the opera-
tional staff to utilize improved process control
(operation) to move the plant to achievement of
optimized performance goals. Approaches that
can be implemented to enhance efforts at
addressing factors in the areas of design, admini-
stration, maintenance and operation are discussed
in the following sections.
Design Performance Limitina Factors
The performance of Type 3 plants is limited by
design factors that require major modifications to
correct. Major modifications require the develop-
ment of contract documents (i.e., drawings and
specifications) and hiring a construction company
to complete the improvements. Examples include
the addition of a sedimentation basin or expansion
of a clear well. Major modifications can some-
times be avoided by operating the plant at a lower
flow rate for longer periods of time; thereby
reducing the unit process hydraulic loading rate to
a range that allows adequate performance to be
achieved. CTA experience with Type 2 facilities
may support the need for major construction; and
once this has been established, utility staff should
pursue this direction similar to a Type 3 facility.
The performance of Type 1 and Type 2 plants can
often be improved by making minor modifications
to the plant. A minor modification is defined as a
modification that can be completed by the plant
staff without development of extensive contract
documents. Examples of minor modifications
include: adding a chemical feeder, developing
additional chemical feed points, or installing baffles
in a sedimentation basin.
A conceptual approach to improving design per-
formance limiting factors is based on the premise
that if each proposed design modification can be
related to an increased capability to achieve opti-
mized performance goals, then the modification
will be supported. For example, if a chemical
feeder is necessary to provide a feed rate in a
lower range than current equipment can provide,
then the design modifications are needed to pro-
vide a capable plant so that desired process con-
trol objectives can be met (see Figure 5-2), The
need for this minor modification can be easily
documented and justified to the administration.
Support for the modification would be expected.
The degree of documentation and justification for
minor modifications usually varies with the associ-
ated costs and specific plant circumstances. For
example, little justification may be required to add
a sampling tap to a filter effluent line. However,
justification for adding baffles to a flocculation
basin would require more supporting information.
Extensive justification may be required for a facility
where water rates are high and have recently been
raised, yet there is no money available for an iden-
tified modification.
The CTA facilitator should assist in developing the
plant staff skills to formally document the need for
minor modifications. This documentation is valu-
able in terms of presenting a request to supervi-
sory personnel and in providing a basis for the
plant staff to continue such requests after the CTA
has been completed. For many requests the spe-
cial study format can be used as the approach for
documenting the change (see Special Studies sec-
tion previously discussed in this chapter). For
modifications with a larger cost, the following
items may have to be added to the special study
format.
77
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• Purpose and benefit of the proposed change
(i.e., how does the change relate to the devel-
opment of a capable plant so that process con-
trol can be used to achieve performance
goals?).
Description of the proposed change and an
associated cost estimate.
Many state regulatory agencies require that modi-
fications, other than repair and maintenance items,
be submitted for their approval. Improvements
requiring state approval may consist of items such
as changing types of chemicals added to the water
(e.g., substituting iron salts for aluminum salts),
adding another chemical feeder (e.g., filter aid
polymer feeder), or modifying filter media. If there
is any doubt as to whether approval is needed, the
facilitator should recommend submitting the pro-
posed modification to the regulatory agency for
approval. Typically, the same documentation that
would be prepared to obtain administrative
approval can be used for the submittal to the
regulatory agency.
Once the proposed modification has been
approved by plant administrators and the state
regulatory agency, the CTA facilitator should serve
as a technical reference throughout the implemen-
tation of the modification. Following completion
of a modification, the CTA facilitator should
ensure that a formal presentation of the improved
plant capability is presented to the administration.
This feedback is necessary to build rapport with
the plant administrators and to ensure support for
future requests. The intent of the presentation
should be to identify the benefits in performance
obtained from the expended resources.
Maintenance Performance Limitina Factors
Maintenance can be improved in nearly all plants,
but it is a significant performance limiting factor in
only a small percentage of plants (2,3,4). The
first step in addressing maintenance factors is to
document any undesirable results of the current
maintenance effort. If plant performance is
degraded as a result of maintenance-related
equipment breakdowns, the problem is easily
documented. Likewise, if extensive emergency
maintenance events are experienced, a need for
improved preventive maintenance is easily recog-
nized. Ideally, maintenance factors should have
been previously identified and prioritized during a
CPE. However, most plants do not have such
obvious evidence directly correlating poor mainte-
nance practices with poor performance; therefore,
maintenance factors often do not become apparent
until the conduct of a CTA. For example, in many
cases CTA activities utilize equipment and proc-
esses more extensively than they have been used
in the past, such as running a facility for longer
periods of time. The expanded use emphasizes
any maintenance limitations that may exist.
Implementing a basic preventive maintenance pro-
gram will generally improve maintenance practices
to an acceptable level in many plants. A sug-
gested four-step procedure for developing a main-
tenance record keeping system is to: 1) list all
equipment, 2) gather manufacturers' literature on
all equipment, 3) complete equipment information
summary sheets for all equipment, and 4) develop
and implement time-based preventive maintenance
activities. Equipment lists can be developed by
touring the plant and by reviewing available
equipment manuals. As new equipment is pur-
chased it can be added to the list. Existing manu-
facturers' literature should be inventoried to iden-
tify missing but needed materials. Maintenance
literature can be obtained from the manufacturer
or from local equipment representatives.
Equipment maintenance sheets that summarize
recommended maintenance activities and sched-
ules are then developed for each piece of equip-
ment. Once these sheets are completed, a com-
prehensive review of the information allows a
time-based schedule to be developed. This sched-
ule typically includes daily, weekly, monthly, quar-
terly, semiannual, and annual activities. Forms to
remind the staff to complete the tasks at the
desired schedule (e.g., check-off lists) can be
developed.
The above system for developing a maintenance
record keeping system provides a reliable founda-
tion for implementing a preventive maintenance
program. However, there are many other good
maintenance systems, including computer-based
systems. The important concept to remember is
that adequate maintenance is essential to reliably
achieve optimized performance goals.
Administrative Performance Limitina Factors
Administrators who are unfamiliar with plant
needs, and thus implement policies that conflict
with plant performance, are a commonly identified
factor. For example, such items as implementing
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minor modifications, purchasing testing equip-
ment, or expanding operator coverage may be rec-
ognized by plant operating personnel as needed
performance improvement steps, but changes
cannot be pursued due to lack of support by non-
technical administrators. Administrative support
and understanding are essential to the successful
implementation of a CTA. The following tech-
niques have proven useful in addressing adminis-
trative factors limiting performance:
• Focus administrators on their responsibility to
provide a "product" that not only meets but
exceeds regulatory requirements on a continu-
ous basis to maximize public health protection.
Often, administrators are reluctant to pursue
actions aimed at improving plant performance
because of a lack of understanding of both the
health implications associated with operating a
water treatment plant and of their responsibili-
ties in producing a safe finished water. The
CTA facilitator must inform and train adminis-
trators about their public health responsibilities
and the associated objectives of achieving
optimized performance goals from their facili-
ties. As an endpoint, administrators should be
convinced to adopt the optimum performance
goals described in Chapter 2. Administrators
should also be encouraged to emphasize to the
operating staff the importance of achieving
these goals.
• Build a rapport with administrators such that
candid discussions concerning physical and
personnel resources can take place (e.g., see
Internal Support section previously discussed
in this chapter).
• Involve plant administrators from the start.
Site visits should include time with key
administrators to explain the CTA activities. If
possible, conduct a plant tour with the admin-
istrators to increase their understanding of
plant processes and problems. Share perform-
ance results on a routine basis.
• Listen carefully to the concerns of administra-
tors so that they can be addressed. Some of
their concerns or ideas may be unrelated to the
technical issues at the plant, but are very
important in maintaining internal support for
ongoing CTA activities.
• Use technical data based on process needs to
convince administrators to take appropriate
actions.
Solicit support for involvement of plant staff in
the budgeting process. Budget involvement
has been effective in encouraging more effec-
tive communication, in motivating plant staff,
and in improving administrative awareness and
understanding. This activity also helps to
ensure continued success after the CTA facili-
tator is gone.
Encourage development of a "self-sustaining
utility" attitude. This requires financial plan-
ning for modification and replacement of plant
equipment and structures, which encourages
communication between administrators and
plant staff concerning the need to accomplish
both short and long term planning. It also
requires development of a fair and equitable
rate structure that requires each water user
(i.e., domestic, commercial, and industrial) to
pay their fair share. The revenues generated
should be sufficient to support ongoing oper-
ating costs as well as short term modification
and long term replacement costs. The CTA
facilitator may choose to encourage the utility
to gain professional help in this area,
depending on the circumstances. Information
is also available from other sources (5,6,7).
Operational Performance Limitinu Factors
Obtaining optimized performance goals is ulti-
mately accomplished by implementing formal
process control procedures, tailored for the par-
ticular personnel and plant. Additionally, the proc-
ess control skills must be transferred to the local
staff for the CTA to result in the plant having the
long term capability to maintain the desired per-
formance goals.
Initial efforts should be directed toward the train-
ing of the key process control decision-makers
(i.e., on-site CTA champion). In most plants with
flows less than 0.5 MGD, one person typically
makes and implements all major process control
decisions. In these cases, on-the-job training is
most effective in developing skills and transferring
capability. If possible, in plants of this size a
"back-up" person should also be trained. This
person may be an administrator or board member
at a very small utility. As the number of operators
to be trained increases with plant size, the need
for classroom training also increases. However, a
significant aspect of the CTA's effectiveness is the
"hands-on" training approach; therefore, any
classroom training must be supported by actual
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"hands-on" applicability and use. The only excep-
tion to this emphasis is in addressing complacency
issues with "what if scenarios" (see What If Sce-
narios section previously discussed in this chap-
ter).
A generic discussion of process control for water
treatment facilities is presented. The CTA facilita-
tor must identify deficiencies in any of the follow-
ing areas and implement activities to address these
limitations, recognizing existing facility and per-
sonnel capabilities.
Process Sampling and Testing:
Successful process control of a water treatment
plant involves producing a consistent, high quality
treated water despite the variability of the raw
water source. To accomplish this goal, it is nec-
essary that the performance of each unit process
be optimized. This is important because a break-
down in any one unit process places a greater
burden on the remaining processes and increases
the chance of viable pathogenic organisms reach-
ing the distribution system and consumers' taps.
By optimizing each unit process, the benefit of
providing multiple barriers prior to the consumer is
realized.
To optimize each unit process, information must
be routinely obtained and recorded on raw water
quality and on the performance of the various unit
processes in the plant so that appropriate controls
can be exercised to maintain consistent treated
water quality. The term "routinely" is stressed
because it is necessary to have the plant achieve
performance objectives at all times when it is in
operation. To allow information to be gathered
and for process control adjustments to be made
whenever water quality conditions dictate, staff
should be available during all periods of operation.
If staffing is not available, continuous water
aualitv monitoring with alarms and shutdown
capability should exist.
The gathering of information in an organized and
structured format involves development of a proc-
ess control sampling and testing schedule. A
basic process control sampling and testing sched-
ule for a conventional plant is shown in Figure 5-9.
Turbidity is the primary test because it provides a
quick and easily conducted measurement to
determine particulate levels and particle removal
effectiveness of individual plant unit processes.
Particle counting can be used in conjunction with
turbidity; however, most small facilities are not yet
using this technology. Raw water turbidity testing
should be conducted on a frequent basis (e.g.,
every four hours) to identify changes in quality.
During periods of rapid change, raw water tur-
bidity should be measured on a more frequent
basis to allow adjustment of coagulant aids. Set-
tled water turbidity from each basin should be
measured a minimum of every four hours to moni-
tor the effectiveness of the settling process and to
document that the integrity of this barrier is being
maintained. If the effectiveness of sedimentation
deteriorates (e.g., due to the unexpected failure of
an alum feeder), the monitoring allows immediate
corrective actions to be taken to minimize or
lessen the impact on downstream unit processes.
Filtered water turbidity should be measured and
recorded on a continuous basis from each filter to
allow constant monitoring of filtered water quality.
Continuous monitoring of filtered water tremen-
dously enhances the operators' capability to prop-
erly time backwashing of filters, to determine the
extent of post backwash turbidity breakthrough,
and to observe if filter control valve fluctuations
are impacting filtered water turbidity.
The process control data should be recorded on
daily sheets, and this data should be transferred to
monthly sheets to allow observation of water
quality trends. For turbidity measurement, maxi-
mum daily values are recorded since this repre-
sents the worst case potential for the passage of
particles. Appendix K includes examples of both
daily and monthly process control sheets. The
daily sheets should include space for recording
actual chemical feed rates and the conversion of
these values to a mg/L dosage so that dosage and
water quality can be correlated. This database can
then be used by the operator to better predict
chemical feed requirements during different raw
water quality events. Graphs and trend charts
greatly enhance these correlation efforts. The use
of computer spreadsheets is encouraged to sup-
port data development and the use of trend charts.
Chemical Pretreatment and Coagulant Control:
The selection and control of chemical coagulants,
flocculants and filter aids is the most important
aspect of improving water treatment plant per-
formance. Therefore, a method to evaluate differ-
ent coagulants and to control the selected coagu-
lant is a primary focus in implementing a process
control program. The special study format is
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especially effective for systematically optimizing
chemical pretreatment.
A coagulant control technique must exist or be
implemented during a CTA if optimized perform-
ance is to be achieved. Example coagulant control
techniques include: jar testing, streaming current
monitors, zeta potential, and pilot filters. Jar
testing is the most common technique and is dis-
cussed in more detail.
To successfully implement jar testing as a coagu-
lant control technique requires understanding of
stock solution preparation and conducting the test
so that it duplicates plant operating conditions as
closely as possible. A typical procedure for pre-
paring stock solutions, conducting jar tests, and
determining mixing energy settings is shown in
Appendix L. Stock solutions must be prepared for
all coagulant chemicals (e.g., metal salts and
polymers) that are going to be added to the jars.
The jar test can be set up to represent plant oper-
ating conditions by setting jar test mixing energy
inputs, mixing times, and settling detention times
similar to those found in the plant (Appendix L).
Plant mixing energy (i.e., G-values) can be deter-
mined by using worksheets presented in the
design section of Appendix F. The use of square
jars is recommended because square jars break up
the circular motion inherent in cylinders and more
accurately represent plant operating conditions.
Chemicals should also be added to the jars to try
to duplicate plant operating conditions. For exam-
ple, if alum is added to the plant flash mix and
polymer is added to a pipeline approximately
30 seconds downstream from the flash mix, the
same sequence should be used in the jar test. The
use of syringes without needles to measure and
deliver the appropriate chemical dose to each jar
simplifies the chemical addition step (i.e., 1 cc =
1 ml). Syringes are available from pharmacies or
veterinary/farm supply stores. The jar test proce-
dure should be adjusted to more closely duplicate
the plant processes. In direct filtration plants, a
small volume (about 50 ml) of flocculated water
should be removed from the jars and passed
through filter paper. Typically, 40 micron filter
paper (e.g., Whatman #40, Schleicher and Schuell
#560) can be used to approximate filter perform-
ance. The filtered samples should be tested for
turbidity, and the sample with the lowest turbidity
represents the optimum chemical dose.
In conventional plants, the jar contents should be
allowed to settle for a period of time relative to the
surface overflow rate of the basins. The approach
for determining the sampling time for settled water
is shown in Appendix L. Allowing the water in the
jar to settle for 30 to 60 minutes and then taking a
sample for turbidity measurement has no relation-
ship to a full-scale plant and should not be done
for collecting useful jar test information. After the
correct sampling time is determined, samples
should be drawn from the sample tap located
10 cm from the top of the jar, and the turbidity of
the sample should be determined. The lowest tur-
bidity represents the best chemical dosage. If
sample taps are not available on the jars, pipettes
can be used to draw-off samples from the jars.
Excellent references are available to guide the
facilitator in implementing jar testing techniques to
obtain optimum coagulant doses (8,9,10,11 I.
Figure 5-9. A basic process control sampling and testing schedule.
Sample
Plant Influent
Sedimentation
Basin
Filter Effluent
Treated or
Finished Water
Sample Location
Tap by Raw Water
Turbidimeter
Top of Filter
Tests
Turbidity
PH
Alkalinity
Flow Rate
Jar Test
Temperature
Turbidity
Frequency
Continuous
Daily
Weekly
Continuous
As Needed
Daily
Every 2 Hours
Turbidimeter Turbiditv Continuous
Lab Tap
PH
CI2 Residual
Turbidity
Daily
Continuous
Every 4 Hours
Sample By
Meter
Operator
Operator
Meter
Operator
Operator
Operator
Meter
Meter
Meter
Operator/Mater
81
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Once the correct chemical dose is determined, the
staff must be able to adjust the chemical feeders
to deliver the desired dosage. This requires the
ability to conduct chemical calculations and to
develop and utilize calibration curves for chemical
feeders. For example, a mg/L dose has to be con-
verted to a feed rate (e.g., Ib/day or mL/min) in
order to correctly adjust chemical feed equipment.
Calibration curves which indicate feed rate setting
versus feeder output must be developed for all
chemical feeders to assure the correct feeder set-
ting for a given desired chemical dosage. Some
chemicals, such as polymers, must often be pre-
pared in dilute solutions prior to introduction into
the plant flow stream. Therefore, the capability to
prepare chemical dilutions must be transferred to
the operators during the CTA. Example chemical
feed calculations are presented in Appendix M,
and a procedure to develop a chemical feeder cali-
bration curve is shown in Appendix J.
Chemical addition must not only be carefully con-
trolled, but the correct type of coagulants, floccu-
lants and filter aids must be applied.
A positively charged product (e.g., metal salt,
cationic polymer, polyaluminum chloride)
should be added for coagulation. Coagulants
typically require good mixing so they should be
added to the rapid mix.
If alum is being utilized with a raw water pH
exceeding 8.0 to 8.5, consideration should be
given to switching to iron salts, sodium alumi-
nate or polymerized products.
. The use of a flocculant polymer to enhance
floe formation and settling can also be investi-
gated.
Investigation of filter aid polymers should be
conducted since these products are often
required if filtered water turbidities less than
0.1 NTU are to be achieved on a continuous
basis. Flocculant and filter aids typically have
an anionic ornonionic charge, and they should
be introduced into the plant flow stream at a
point of gentle mixing, since excessive turbu-
lence will shear the polymer chains and reduce
the product effectiveness.
For low alkalinity waters (e.g., <20 mg/L),
consideration should be given to adding alka-
linity (e.g., soda ash, lime).
Some chemicals should not be added at the same
location. For example, the addition of lime and
alum at the same point is counter-productive if the
lime is raising the pH to the extent that the opti-
mum range for alum coagulation is exceeded. The
addition of powdered activated carbon at the same
location as chlorine is also detrimental since the
carbon will quickly adsorb the chlorine, inhibiting
the ability of both chemicals. The addition of chlo-
rine, potassium permanganate or other oxidant, in
combination with some polymers, will result in the
oxidation of the polymer, with a subsequent
reduction in its effectiveness.
Unit Process Controls:
Optimization of unit processes requires that those
parameters that can be controlled to adjust proc-
ess performance be identified and incorporated
into a plant specific process control program.
Ideally, existing process control procedures and
input from plant staff are used to develop this
program, This usually must be supplemented by
information from the CTA facilitator based on
experience at other facilities, equipment manuals,
or networking with peers. Multiple unit processes
and their unique control features exist in water
treatment facilities. An overview of the more con-
ventional unit processes and their associated con-
trols is presented in the following sections.
Mixing. Flocculation. and Sedimentation. The
main controls for mixing, flocculation and sedi-
mentation unit processes include the following:
. Plant process flow rate and flow splitting
between unit processes operating in parallel
• Type of chemical and chemical feed rate (see
Chemical Pretreatment and Coagulation Con-
trol section previously discussed in this
chapter)
. Flocculation energy input
. Sludge removal
Floe break-up at the effluent of sedimentation
tanks
Plant flow rate is a primary control at many small
plants that are operated for less than 24 hours
each day. At these plants an excessive hydraulic
loading rate on the flocculation/sedimentation
processes can be avoided by operating at a lower
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flow rate for a longer period of time. This pro-
vides an option to meet more rigorous perform-
ance requirements with existing units without
major capital improvements. The capability to
reduce plant flow rate to improve performance is
offset by the need to staff the plant for longer
periods of time, which adds to operating costs.
Therefore, plant administrators and staff, in con-
junction with the CTA facilitator, must evaluate
these options.
If multiple basins exist, flow splitting to ensure
equal loading to the units should be monitored and
controlled. Often, performance monitoring (e.g.,
turbidity) of individual sedimentation basins can be
used to indicate unequal flow splits.
Flocculation energy input is often fixed at small
plants, either by hydraulic flocculation systems or
by constant speed flocculation drives. However,
flocculation energy, if low enough to allow forma-
tion of settleable floe, is not considered an essen-
tial variable to achieve desired performance of a
small plant. More important are the plug flow
characteristics of the flocculation system. Plug
flow characteristics, similar to those found in most
hydraulic flocculation systems, result in the forma-
tion of floe particles of uniform size, which greatly
aids settleability. As such, greater priority may be
placed on installing baffling in flocculation systems
rather than trying to optimize mixing energies.
Adequate time for chemical reaction is typically
more important when the water temperature is
less than 5°C, and under these conditions per-
formance can be improved by reducing plant flow
rate.
Sludge needs to be removed from conventional
sedimentation basins frequently enough to prevent
solids carryover to the filters. The frequency of
sludge removal can be determined by using a core
sampler to monitor build-up in the basin. The
duration of sludge removal can be determined by
collecting samples during draw-off (e.g., every
30 seconds) and determining when the sludge
begins to thin. A centrifuge, graduated cylinder,
or Imhoff cone can be used to observe the density
changes.
Sludge control is very important in the operation of
reactor type upflow sedimentation basins that
operate using a sludge blanket. The reactor sec-
tion of the basin must be monitored daily, and the
appropriate amount of sludge must be removed
from the basin to maintain the optimum reactor
concentration and sludge blanket depth. Inade-
quate monitoring of the basin can lead to a loss of
the sludge blanket over the weirs, which signifi-
cantly degrades unit process performance and,
ultimately, filter performance. A 100 ml gradu-
ated cylinder has been used to monitor sludge
mass in a reactor type basin. A volume of 18 -
25 ml of sludge in a 100 ml cylinder, after five
minutes of settling, has provided satisfactory per-
formance at one location (12).
Another issue to consider is the possibility of floe
breakup after the settled water leaves the sedi-
mentation basins. Depending on the chemical
conditioning used in the plant, coagulated particles
may break apart because of turbulence when the
settled water is conveyed to the filtration process
(e.g., sedimentation effluents with large elevation
changes at the discharge of the basin). If floe
breakup is suspected, operational changes, such
as flooding the effluent weirs, can be tried to
assess if performance improves. Additionally, the
use of a filter aid can assist in overcoming the det-
rimental impacts of floe breakup.
Filtration. The controls for the filtration process
include the following:
• Coagulation control
. Filtration rate control
. Filter aid chemical and chemical feed rate
• Backwash frequency, duration and rate
. Filter to waste
Proper chemical pretreatment of the water prior to
filtration is the key to acceptable filter perform-
ance. Improper coagulation (e.g., incorrect feed
rate, inappropriate coagulant) fails to produce par-
ticles that can be removed within the filter or to
produce particles large enough that they can be
removed by sedimentation. Because of this
impact, the importance of a good plant specific
coagulant control technique cannot be overempha-
sized.
For waters that are properly chemically condi-
tioned, filter flow rate becomes less critical. The
most important aspect of flow rate relative to filter
performance is the magnitude and rate of change
of flow rate adjustments (4,131. Rapid, high mag-
nitude flow rate can cause a large number of
particles to be washed through the filter. This can
be observed by the associated increases in
turbidity measurements or particle counts. Since
the filters are the most effective barriers to cysts,
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even short term performance deviations can
potentially expose consumers to significant
concentrations of cysts.
Filtration rate changes most often occur during
backwashing events, raw water pumps cycling on
and off, start-up of filters, and periods when filter
rate controllers malfunction.
. When one filter is removed from service for
backwashing, many operators leave plant flow
rate the same and direct the entire plant flow
to the remaining filter or filters. At plants with
a limited number of filters this places an
instantaneous, high magnitude flow increase
on the remaining filters. This is frequently
inherent in automatic backwash control sys-
tems where the plant was not designed to
adjust flow during backwash. This can be
prevented by lowering the plant flow rate prior
to removing the filter from service, thereby
controlling the hydraulic loading to the
remaining on-line filters.
. Rapid changes in plant influent flow by starting
and stopping constant speed raw water pumps
also encourages the loss of particles from fil-
ters. This may be prevented by using a man-
ual or automatic control valve to slowly adjust
plant influent flow rate.
• Start-up of dirty filters can also result in the
washout of entrained particles. Backwashing
of filters prior to returning them to service is
essential to maintain the integrity of this unit
process.
. Malfunctioning filter rate control valves can
result in rapid changes in filtration rates. The
impact of filter rate control valve malfunction-
ing is difficult to identify without continuous
on-line monitoring. An ongoing preventive
maintenance program can be effective to keep
the valves in good working order and to avoid
this source of poor filter performance.
The utilization of a low dose of filter aid polymer
can improve filtered water quality from dual or
mixed media filters. These products are very
effective but, if overdosed, can quickly blind a
filter. They, therefore, should be used at optimum
doses (i.e., typically less than 0.1 mg/L) to avoid
excessively short filter runs. Once activated,
these products are subject to shearing because of
their long polymer chains and should be fed at
points of low turbulence, such as flocculation
basins or sedimentation basin effluent lines,
During a filter run, backwashing must occur before
particle breakthrough occurs. Filtered water tur-
bidity should be monitored continuously, and the
filter should be backwashed at the first indication
of an increasing turbidity trend. Particle counters
have recently been used to monitor individual fil-
ters at some plants. Results have shown that par-
ticle breakthrough is indicated prior to deteriora-
tion in filtered water turbidity (14,15). Excessive
filter runs (e.g., greater than 48 hours) can some-
times make filters difficult to clean during back-
wash due to media compaction and can cause an
increase in biological growth on the filter. How-
ever, filter run times are site-specific and should
be determined at each treatment plant. One
method to assess filter run time is to conduct a
special study involving microscopic evaluations of
filtered water throughout the filter run (16,17).
Particle breakthrough, as measured by turbidity or
particle counting, should always remain a primary
control in establishing filter run times.
The filter backwash duration and intensity must be
sufficient to clean the filter, but not so great that
damage occurs with the support gravel and
underdrain system or media is washed out of the
filter. A filter bed expansion test can be used to
assess the adequacy of backwash rate (see the
Field Evaluations section discussed in Chapter 4).
The backwash duration should be long enough to
adequately clean the media, otherwise filter per-
formance will degrade and mudballs could form in
the media. The filter should be probed periodically
(e.g., semi-annually) to inspect for support gravel
problems and to check media depths. Proper
cleaning can be evaluated by inspecting the filter
media for mudballs and overall cleanliness. Filters
occasionally require the addition of media (i.e.,
topping due to washout of media during back-
wash).
Operating guidelines should be developed to
describe consistent methods of backwashing fil-
ters. Guideline content should include measures
to: 1) prevent rapid flow rate increases to the
remaining on-line filter(s), 2) ensure that the filter
is properly cleaned, 3) prevent damage to the filter
by operating at excessive flow rates or opening
valves too quickly, and 4) return a filter to service.
When a filter is returned to service following
washing, it should be rested for a period of time to
allow the media to consolidate before it is
restarted, or it should be slow-started by gradually
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increasing the filtration rate over a period of
30 minutes (18). Conducting a special study to
define backwash procedures that result in the
achievement of optimized performance goals
should be completed and serve as the foundation
for the backwash guideline.
At some plants where operational adjustments do
not allow filters to return to optimized performance
goals within 15 minutes following backwash, more
aggressive steps may be required. These include
addition of coagulant to the water used to back-
wash the filter or modifications to provide filter to
waste capabilities. Some utilities have found that
addition of coagulants to the backwash water
helps in minimizing turbidity spikes by conditioning
the filter prior to returning it to service. Filter to
waste allows the initial filtered water to be
directed to a drain until the quality achieves the
performance criteria, at which time it can be redi-
rected to the clean/veil. These approaches should
only be implemented after other less costly
approaches described above have proven ineffec-
tive during a series of special studies.
Disinfection. The controls for the disinfection
process include the following:
. Contact time
• Disinfectant concentration
Disinfectant application point
To prove adequate disinfection, the plant unit
processes, including disinfection, must meet a
state-specified criteria for log reduction/inactiva-
tion of Giardia and viruses. Presently, this criteria
is defined as achieving a CT value outlined in the
SWTR Guidance Manual (19). The CT value,
which is the concentration of disinfectant (mg/L)
multiplied by the effective contact time (minutes)
prior to the first user's tap, is affected both by
plant flow rate and the concentration of the disin-
fectant applied. The maximum concentration of
disinfectant that can be added because of effec-
tiveness and aesthetic concerns (taste and odor) is
normally 2.5 mg/L as free chlorine residual.
Therefore, adjustments to contact time offer the
best process control option for optimizing disinfec-
tion. Most plants apply chlorine as a disinfectant
to the filtered water prior to a clean/veil. The
clean/veil is typically designed as a storage basin
for backwash water or a wet well for finished
water pumps and not as a disinfectant contactor.
As a result, there are no baffles or other means to
make the basin plug flow, and the clearwell
basin's small size provides limited contact time.
Reducing the plant flow rate, operating at greater
clearwell depth, or baffling the basin can often be
used to gain more effective contacting.
Adding a chlorine application point prior to the
plant rapid mix to provide contact time in raw
water transmission lines and flocculation. and
sedimentation basins can also be evaluated. How-
ever, this practice, while allowing greater CT val-
ues to be obtained, may cause the formation of
excessive disinfection by-products. State regula-
tory personnel should be consulted prior to initiat-
ing this practice.
If operational changes cannot be made to achieve
the specified CT values, modifications to the plant
may be required to provide sufficient disinfectant
contact time. It is noted that actual levels of disin-
fection required for water treatment plants is pres-
ently established by the state where the plant is
located. Additionally, future regulations may
impact disinfection practices (20). Modifications
to a plant's disinfection system should include a
thorough review of proposed regulations and
coordination with the state regulators.
5.3 Case Study
A case study of a CTA is difficult to present
because many of the activities are conducted over
a long period of time and include numerous events
such as on-site training, transfer of technical and
interpersonal skills, weekly data review, phone
consultations and site visits, and multiple special
studies. Since these activities do not lend them-
selves readily to the case study format, an abbre-
viated overview of a CTA will be presented.
5.3.7 CPE Findings
A CPE was conducted at a conventional water
treatment plant that included facilities for chemical
addition, rapid mixing, flocculation, sedimentation,
filtration, and clearwell storage. Raw water was
supplied to the plant from a reservoir fed by a
river. The facility was constructed in 1994 and
had a rated design capacity of 13 MGD. The plant
is operated 24 hours per day and serves approxi-
mately 23,000 people.
The performance assessment of the plant revealed
that this new facility had not consistently met the
0.5 NTU turbidity limit required by the 1989
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SWTR (21) during its first year of operation. In
fact, enforcement action was being considered by
the state regulatory personnel due to the frequent
violations. Turbidity values at the levels observed
indicated that the plant was definitely not achiev-
ing optimized performance goals as described in
Chapter 2. Along with not meeting the filtered
water optimization goals, the plant had inconsis-
tent sedimentation basin performance with peaks
as high as 8 NTU. Turbidity spikes of 0.6 NTU
after backwash were also found.
The major unit process evaluation revealed that all
of the major unit processes had sufficient physical
capacity to support achievement of optimized per-
formance goals. The rated design capacity of the
facility was 13 MOD, and the peak instantaneous
flow rate was 7.5 MGD. All of the major unit
processes were rated above the 13 MGD capa-
bility.
Three major performance limiting factors were
identified in the CPE. The highest ranking factor
was related to the operations staff's capability to
apply proper process control concepts to improve
the performance of their facility. Performance
monitoring and process control testing were not
consistent, and data was not developed nor used
to make process adjustments. Limited efforts had
been completed to define optimum chemical feed
strategies. Backwashing practices were inconsis-
tent and not focused on limiting turbidity spikes or
shortening recovery time after filters were placed
back in service.
The second factor was related to administration.
Specific administrative policies were limiting per-
formance of the plant by failing to create an envi-
ronment necessary to support optimization. Start-
up training for the operators in connection with
the new facilities was deleted as a cost saving
measure. Optimization goals were not embraced
by administrative personnel, and personnel
changes at the plant had resulted in conflicting
directives to the plant staff and confusion over
who was in charge.
The third factor was related to design with several
issues related to process controllability. The loca-
tion of the recycle line from the sludge and back-
wash storage pond was after the point of chemical
addition to the raw water. This prevented the
plant staff from properly monitoring and control-
ling the coagulation chemistry of the blended raw
water. Chemical feed facilities were also contrib-
uting to the performance problems since several
chemical feed pumps were oversized for current
flows and sufficient flexibility had not been pro-
vided with respect to adding chemicals at various
locations in the plant.
A CTA was initiated at the plant to attempt to
achieve optimized performance goals. The dura-
tion of the CTA was about 18 months, and high-
lights from the project are summarized below.
5.3.2 CTA Activities
5.3.2.1 Initial Site Visit
During the initial site visit, the CTA facilitator used
the CPE results and the priority setting model to
prioritize activities. At the CTA facility, caution
had to be taken to consider the potential adverse
impact of any changes on plant performance and
public health since the facility was producing
unacceptable finished water quality. A contin-
gency plan was developed that included plant
shutdown, lowering plant flow rate, and initiating
an order to boil water. Fortunately, the staff had
improved process monitoring (e.g., began indi-
vidual filter monitoring and initiated sedimentation
basin monitoring) after the CPE exit meeting.
These steps had resulted in process control
changes that allowed improved performance and,
for the most part, compliance with the SWTR.
After the CPE, the plant staff had also dealt with
the oversized chemical feed pumps by interchang-
ing with others within the plant. They also made
provisions for some additional chemical feed
points.
A key step in the CTA was the identification of the
local CTA champion. The person selected was the
new superintendent for the utility. Although he
was new to the position, it was felt that he was
the best choice for utility champion and was the
best person to assist the CTA facilitator in making
the necessary changes to the "old ways of doing
business."
Jar testing procedures were developed, and rou-
tine testing was initiated. A sampling and jar test
set-up modification was implemented to allow jar
testing to be conducted on the blended raw water
and recycle water. Based on the jar test results,
the need for coagulant dosage adjustments was
indicated. The operations staff participated in all
of the testing and data development. Despite the
results, the staff was reluctant to make changes.
This stemmed from the fact that jar testing had
-------
never been a routine activity at the plant and,
thus, the operators lacked the confidence to take
jar tests results and use the information to make
chemical feed changes in the plant. However, a
staff consensus of "We don't think it will work,
but we can try it" was achieved. Preliminary
results during the site visit were very encouraging.
A formal meeting was set up between the CTA
facilitator and the plant staff to discuss additional
high priority items. The topics for discussion were
established by the CTA facilitator. During this
meeting, optimized unit process performance goals
were established. The guidelines in Chapter 2
were used to set the performance goals. Limited
staff acceptance for the goals was accomplished
at this meeting because they were more focused
on just being able to meet the SWTR require-
ments. In addition, they did not have the confi-
dence that the optimized treatment goals could be
met. Sampling, monitoring and data recording
procedures were also discussed. The negative
impact of the location of the recycle line was also
discussed, and it was decided to pursue modifica-
tion of this line with the utility administration.
An action list was developed which included
assignments to the staff to develop operational
guidelines on jar testing and unit process perform-
ance sampling, monitoring, and data recording.
Arrangements were made with the on-site CTA
champion to provide plant monitoring and per-
formance data to the CTA facilitator on a weekly
basis.
Prior to the conclusion of the site visit, the CTA
facilitator and the on-site CTA champion met with
the City Manager and the Director of Public
Works. The basis for the meeting was to report
on the process control changes and the action list
and to initiate discussions on the desired recycle
line modification. The initial response on the need
for the recycle line was "Wasn't that the design
consultant's responsibility?". The CTA facilitator
identified that the optimized performance goals
that were being pursued required much closer con-
trol than would be required to just meet the SWTR
requirements. The utility was encouraged to pur-
sue modifications on their own, and the adminis-
trators agreed to begin an evaluation of the possi-
ble approaches for completion of -the modification
and associated costs. A discussion was also held
concerning the less-than-enthusiastic response by
the staff to the new procedures and performance
goals. This information was provided to lay the
groundwork for administrative support if condi-
tions didn't change. Questions were received
from the administrators concerning the need and
costs of achieving water quality goals that
exceeded regulatory requirements. The public
health implications were explained by the CTA
facilitator, with only limited acceptance on behalf
of the administrative personnel. A report which
summarized the progress made and the action list
that was developed was prepared by the facilitator
at the conclusion of the site visit.
5.3.2.2 Off-Site Activities
The on-site CTA champion provided drafts of the
agreed upon guidelines as well as weekly summa-
ries of plant data. The CTA facilitator reviewed
the guidelines and provided written comments to
the utility. Data review was also completed by the
CTA facilitator, and trend charts were developed
to aid in data interpretation.
Phone calls were made on a weekly basis to dis-
cuss data trends and to follow up on action items.
Feedback from the CTA champion indicated that
even after his best efforts, the plant staff were still
balking at the increased sampling and laboratory
activities and that the administration had not pur-
sued the recycle line modification. A decision was
made to make a return site visit to address these
issues,
5.3.2.3 Follow-Up Site Visit
During the second site visit the nominal group
process was used to establish priorities for con-
tinued optimization activities (see Priority Setting
Tools section previously presented in this chapter).
The issue of increased work load and lack of rec-
ognition was rated high and received extensive
discussion. The CTA facilitator used the trend
charts developed from plant data to show the
improvements that had been accomplished in
achieving optimized performance goals, Several of
the operators took pride in these accomplishments
and voiced support for the increased process con-
trol activities. However, one operator remained
adamantly opposed to the changes. At the con-
clusion of the discussion it was decided to con-
tinue the additional process control effort for at
least several more months.
The concept of special studies was introduced
during the staff meeting, and two special studies
were developed to evaluate the use of a filter aid
87
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polymer and to assess control of backwash spikes.
Additional guidelines for turbidimeter calibration
and sludge removal from the sedimentation basins
were also discussed. An action list was developed
to conduct the special studies, draft the additional
guidelines, and to pursue the modification to the
recycle line.
At the conclusion of the site visit, an administra-
tive exit meeting was held where the preliminary
graph of improved performance was presented.
The results of the plant meeting and discussions
were presented, and support for the recycle line
modification was again requested. These discus-
sions revealed that the administrators did not
completely understand the importance of the recy-
cle line modifications with respect to being able to
perform effective process control. Once they
understood the need for timely modifications to
the recycle line, these modifications were quickly
made.
A report was prepared by the facilitator at the
conclusion of the second site visit which summa-
rized the progress made and the updated action
list. The site visit was an effective mechanism to
demonstrate improved performance to the utility
staff, provide positive feedback on achieving
interim milestones, and reinforce the long term
project goals. This site visit also demonstrated the
importance of the facilitator in resolving issues
that the CTA champion finds difficult to resolve on
his/her own.
5.3.2.4 Other CTA Activities
not quickly accepted by all of the operators. One
recalcitrant operator was found to be undermining
the CTA champion's efforts to get consistent
process control procedures implemented. A sig-
nificant amount of the time during the CTA was
involved in obtaining the administrative support to
reassign this person to maintenance.
After the CPE, the plant staff made changes to the
existing piping so that polymers could be added
before and after the rapid mix basin. During the
CTA, a decision was made that a separate polymer
feed system would also be needed so that a filter
aid could be added to the sedimentation basin
effluent. This was deemed necessary to meet the
filter effluent and backwash spike turbidity goals.
Controlling the turbidity spikes after filter back-
wash required a significant effort by the plant
staff. Many special studies were completed to
evaluate a variety of filter backwash procedures,
including gradual ramping of the backwash flow
and resting of the filter before returning it to serv-
ice. Problems were also found with the sample
tap locations when the special study results
showed that the spikes were eliminated on two of
the filters but remained on the other two.
5.3.2.5 CTA Results
Figure 5-10 graphically depicts the success of the
case history CTA. There was a dramatic change
from highly variable finished water prior to the
CPE to stable, high quality finished water after the
CTA.
Activities conducted by the CTA facilitator off-site
and on-site (an additional two site visits)
continued, using a similar format for another
twelve months. During that time, the modification
to the recycle line was accomplished, and process
control skills were transferred to all of the plant
staff. A significant part of transferring process
control skills was getting all of the operators to
accurately record individual filter effluent
turbidities on the plant's process control sheets.
Procedures had to be developed and implemented
where readings above a certain level (0.1 NTU)
had to be verified before being recorded. A total of
23 operational guidelines were developed by the
plant staff.
Acceptance of the optimization goals and the
process control procedures to achieve them were
Along with the optimized performance from their
filters, Figure 5-I 1 shows how the plant also
achieved the settled water turbidity performance
goals. Additionally, after much effort, the plant
has essentially eliminated the turbidity spikes after
backwash, as shown in Figure 5-I 2. A significant
benefit achieved from the CTA was the develop-
ment of staff tenacity to address any deviations
from the optimized water quality goals. This
tenacity, coupled with the experience and confi-
dence that the staff gained during the CTA, sup-
ports the long term achievement of the optimiza-
tion goals. This is demonstrated in Figure 5-13
which shows the performance of this plant for a
year after completion of the CTA without the
assistance of the facilitator.
88
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Figure 5-10. Performance improvement during CTA project - filter effluent.
0,0
Jan-94 Apr-94 Jul-94 Oct-94 Jan-95 Apr-96 JuI-95 Oct-95 Jan-96 Apr-96
Figure 5-11. Performance improvement during CTA project - sedimentation basin effluent.
3.00
Apr-95 Jun-95 Aug-95 Oct-95 Dee-95 Feb-96
Date
89
-------
Figure 5-12. Performance improvement during CTA project - filter backwash spikes.
0.3
0.2
•a
5
0)
0.1
0.0
10 16 20
Time After Filter Start-Up
25
30
Figure 5-13. Plant performance after CTA.
0.25
0.00
Jan-97 Mar-97 May-97 Jul-97 Sep-97 Nov-97 Jan-98 Mar-98
Date
90
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Additionally, the administrators developed pride in
their utility's capability to maintain consistent, high
quality treated water that exceeds regulatory
requirements. Most importantly, the consumers of
the utility's water have benefited from the high
level of protection against water-borne disease
outbreaks.
A final CTA report was prepared and was used to
present the benefits of utilizing the CTA process to
plant administrators.
5.4 References
When an NTIS number is cited in a reference, that
reference is available from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650
1. Public Notification Regulation Rule. October
1987. U.S. Environmental Protection Agency,
40 CFR, Part 141, Subpart D, Reporting, Pub-
lic Notification and Record Keeping.
2. Renner, R.C., B.A. Hegg, and J.H. Bender.
March 1990. EPA Summary Report: "Opti-
mizing Water Treatment Plant Performance
With the Composite Correction Proaram.
EPA 625/8-90/017, USEPA Center for Envi-
ronmental Research Information, Cincinnati,
OH.
3. Renner, R.C., B.A. Hegg, and D.L. Fraser.
February 1989. "Demonstration of the Com-
prehensive Performance Evaluation Technique
to Assess Montana Surface Water Treatment
Plants. " Presented at the 4th Annual ASDWA
Conference, Tucson, AZ.
4. USEPA. February 1991. Handbook: Opti-
mizing Water Treatment Plant Performance
Using the Composite Correction Proaram. EPA
625/6-91/027, USEPA Office of Research and
Development, Cincinnati, OH.
5. Water Rates and Related Charges (M25).
1986. AWWA Reference Manual, No.
30026, Denver, CO.
6. Small System Guide to Rate Setting. Commu-
nity Resource Group, Inc., Springdale, AK.
7 . USEPA. 1989. A Water and Waste water
Manaaer's Guide for Staving Financially
Healthy. USEPA (#430-09-89-004), Cincinnati,
OH.
8. Hudson, H.E., Jr. 1980. Water Clarification
Processes: Practical Design and Evaluation.
Van Nostrand Reinhold Co.
9. Singley, H.E. June 1981. "Coagulation Con-
trol Using Jar Tests." Coagulation and Filtra-
tion: Back to Basics, Seminar Proceedings,
1981 Annual Conference, p.85. AWWA,
Denver, CO.
10. Hudson, H.E. and J.E. Singley. June 1974.
"Jar Testing and Utilization of Jar Test Data."
Upgrading Existing Water Treatment Plants.
AWWA Seminar Proceedings, VI-79. Denver,
CO.
11. AWWA.
1992.
Ooerational Control of
Coaaulation and Filtration Process.
Manual M37. AWWA, Denver, CO.
AWWA
12. Process Applications, Inc. December 1990.
"Summary Report - Loma, Montana Water
Treatment Plant Composite Correction Pro-
gram." Unpublished report.
13. Cleasby, J.L., M.M. Williamson, and E.R.
Baumann. 1963. "Effect of Filtration Rate
Changes on Quality," Journal AWWA, 55:869-
878. Denver, CO.
14. West, T., P. Demeduk, G. Williams,
J. Labonte, A. DeGraca, and S. Teefy. June
1997. "Using Particle Counting to Effectively
Monitor and Optimize Treatment." Presented
at AWWA Annual Conference, Atlanta, GA.
15. Veal, C., and B. Riebow. May 1994. "Particle
Monitor Measures Filter Performance. "
Opflow, Vol. 20, No. 5. AWWA, Denver, CO.
16. Hibler, C.P. and CM. Hancock. "Inter-
pretation - Water Filter Participate Analysis."
CH Diagnostic & Consulting Service, Inc., Fort
Collins, CO.
17. Hibler, C.P. "Protocol - Sampling Water for
Detection of Waterborne Particulates, Giardia,
and Cryptosporidium." CH Diagnostic &
Consulting Service, Inc., Fort Collins, CO.
91
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18. Pizzi, N. 1996. "Optimizing Your Plant's Filter 21. "Surface Water Treatment Rule." June 1989.
Performance." Opflow, Vol.22, No.5. AWWA, From Federal Register, Vol. 54, No. 124, U.S.
Denver, CO. Environmental Protection Agency, 40 CFR,
Parts 141 and 142, Rules and Regulations, Fil-
19. USEPA. October 1989. Guidance Manual for tration/Disinfection.
Compliance With the Filtration and Disinfection
Reauirements for Public Water Systems Using
Surface Water Sources. NTIS No. PB-90 148-
016, USEPA, Cincinnati, OH.
20. USEPA. 1997. Microbial/Disinfection By-
Products Federal Advisory Committee Agree-
ment in Principle. Dated June 9, 1997.
Signed July 15, 1997.
92
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Chapter 6
Findings From Field Work
6.1 introduction
This chapter summarizes findings from the field
activities and draws conclusions concerning future
efforts and potential impacts of utilizing the CCP
approach in improving performance of surface
water treatment plants.
The field activities conducted to refine the CCP
approach have focused on three distinct areas:
. Development/application of the process to
water treatment plants.
. Demonstration and transfer of principles and
practices to state, third-party and utility per-
sonnel.
• Incorporation of the process into an area-wide
optimization program (see Chapter 3).
In addition, the CCP approach has evolved from a
focus of achieving compliance with the Surface
Water Treatment Rule (1) to one of minimizing the
passage of Ctyptosporidium oocysts through the
treatment plant by achieving optimized perform-
ance goals (see Chapter 2).
The basis for the conclusions and results
described in this chapter is drawn from 69 CPEs
and 8 CTAs conducted in 17 states and Canada.
The geographical distribution of the CPEs and
CTAs is described in Table 6-I. The plants had a
wide range of peak instantaneous operating flow
rates and populations served. Thirty-five percent
of the plants served communities with populations
less than 3,300, with peak flow rates typically
less than 3.0 MGD, while 10 percent of the plants
provided service to populations in excess of
50,000 persons. The majority of the systems
served small to medium-sized communities. Larger
plants typically required more time to conduct the
plant tour and interviews; otherwise, the CPE pro-
cess was only minimally affected by plant size.
All of the plants evaluated used surface water for
their raw water source. The majority of the plants
utilized conventional treatment consisting of rapid
mix, flocculation, sedimentation, filtration and
disinfection. Several of the plants that were
evaluated operated in a direct or in-line direct fil-
tration mode. Three lime softening plants were
evaluated. In addition, several types of unique
filtration processes were evaluated; they included
automatic valveless gravity filters, traveling bridge
backwashing filters, and several types of pressure
filters. The CCP approach was found to be appli-
cable regardless of plant size or type.
Table 6-1. Geographical Distribution of CPEs and
CTAs
CPEs CTAs
Montana
Maryland
West Virginia
Texas
Massachusetts
Pennsylvania
Canada
Colorado
Navajo Tribal
Lands in Utah,
New Mexico
11 3
10
a i
7 1
4
4 1
4
3 1
2 1
CPEs
Louisiana
Rhode Island
Wisconsin
Kentucky
Ohio
California
3
3
3
2
2
1
Vermont 1
Washington
1
6.2 Results of Comprehensive Perform-
ance Evaluations
6.2.7 Major Unit Process Capability
A summary of the major unit process capability for
the 69 plants is shown in Table 6-2. The unit
processes were assigned a rating of Type 1, 2 or
3 depending on their projected ability to consis-
tently meet optimized performance goals at the
peak instantaneous operating flow rates under
ideal conditions. Ideal conditions are those in
which all ancillary features of a unit process are
operational (e.g., paddles, drive motors and inter-
basin baffles are functional in a flocculation basin)
and process control activities have been optimized.
93
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As described in Chapter 4, a Type 1 or 2 rating
indicates that the unit processes are potentially
adequate to consistently meet optimized perform-
ance goals. A unit process rated as Type 3 would
not be expected to perform adequately.
Table 6-2. Summary of the Major Unit Process
Ratings for 69 Plants
Flocculation
Sedimentation
Filtration
Post-Disinfection
Only
Pre- & Post-
Disinfection
Type 1
Percent
of Plants
88%
77%
86%
46%
86%
Type 2
Percent
of Plants
7%
17%
13%
3%
5%
Type3
Percent
of Plants
5%
6%
1%
51%
9%
The basis for rating the major unit processes has
been consistent for all 69 CPEs except for the
disinfection process. The disinfection process ini-
tially was evaluated on the ability of a plant to
provide two hours of theoretical detention time.
This was done for the initial nine plants evaluated
in Montana. The disinfection evaluation was later
modified based on the SWTR CT requirements.
The disinfection ratings for the initial nine Montana
CPE sites are not included in the summary in
Table 6-2.
As shown in Table 6-2, the flocculation, sedimen-
tation and filtration unit processes were typically
judged adequate to justify attempts to optimize
performance using existing facilities (e.g., major
unit processes rated either Type 1 or 2). Only 5
percent of the flocculation and 6 percent of the
sedimentation processes were judged to require
major capital improvements. Also, the filtration
processes were almost always rated as being
Type 1. In some circumstances filters that had
been rated as Type 1 were found to require modi-
fications such as media replacement because of
damaged underdrains or support gravels; however,
media replacement was not judged to be a major
construction requirement. In some circumstances,
reducing the peak instantaneous flow rate and
operating the plant longer enabled a Type 3 unit
process to be reclassified as Type 2 or 1. Based
on these findings, it was projected that 92 percent
of the plants evaluated could meet optimized per-
formance goals without major capital construction.
Disinfection was evaluated at 60 of the facilities
with respect to their ability to meet the CT
requirements of the SWTR. Post-disinfection
alone was only found capable to meet the CT
requirements in 49 percent of the plants. The
primary deficiency was the limited contact time of
the clean/veils that were typically designed to pro-
vide backwash water storage or wet wells for high
service pumps. The majority of disinfection con-
tact basins were unbaffled and operated on a fill
and draw basis. This operation is less than ideal
for optimizing contact time.
For facilities where both pre- and post-disinfection
was practiced, 91 percent of the plants were pro-
jected to comply with the SWTR CT requirements.
Although use of both pre- and post-disinfection
may allow some plants to provide adequate disin-
fection capability with existing facilities, its appli-
cation may be limited due to requirements related
to the allowable levels of disinfection by-products
(DBFs). Proposed requirements of the Disinfec-
tants and Disinfection By-Products Rule (2) would
establish DBP requirements for all systems. The
final regulations regarding CT credit for predisin-
fection will be established by individual states.
Because the regulations governing disinfection are
changing, it is likely that capability projected from
the historical CPE disinfection unit process evalua-
tions will change.
6.2.2 Factors Limiting Performance
Factors limiting performance were identified for
each of the 69 CPEs utilizing the list of factors
described in Appendix E. An average of eight fac-
tors was identified at each plant. Each factor was
given a rating of A, B, or C, depending on its
impact on performance (see Chapter 4). To
assess the degree of impact from an overall basis,
A factors (i.e., major impact on performance) were
assigned 3 points, B factors (i.e., moderate impact
on performance on a continuous basis or a major
impact on performance on a periodic basis) were
assigned 2 points, and C factors (i.e., minor
impact on performance) were assigned 1 point.
The summary of factors that occurred most
frequently and the degree of impact of the factors
identified during the 69 CPEs are presented in
Table 6-3.
94
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Table 6-3. Most Frequently Occurring Factors Limiting Performance at 69 CPEs
Rank
1
2
3
4
5
6
7
8
9
10
11
12
Factor
Applications of Concepts
Disinfection
Process Control Testing
Sedimentation
Filtration
Administrative Policies
Process Flexibility
Process Controllability
Flocculation
Water Treatment Understanding
Plant Staff
Ultimate Sludge Disposal and/or
Backwash Water Treatment
Category
Operations
Design
Operations
Design
Design
Administrative
Design
Design
Design
Operations
Administrative
Design
Number
of Points
113
112
88
79
72
69
58
47
45
41
40
39
Number
of Plants
43
39
36
39
29
29
29
22
23
14
18
15
Three of the top twelve factors were related to
operations: Number I- Application of Concepts,
Number 3 - Process Control Testing, and Number
10 - Water Treatment Understanding. The overall
high ranking of operational-related factors is of
major significance. Consistently achieving opti-
mized performance goals requires optimization of
each unit process in the treatment scheme. Addi-
tionally, achieving optimized performance goals
requires timely adjustments in response to chang-
ing raw water quality.
Essentially, inadequate or marginal process control
programs existed in over half of the plants where
CPEs were conducted. At 62 percent of the
plants, the operators had problems applying their
knowledge of water treatment to the control of the
treatment processes. These operators could dis-
cuss coagulation chemistry and filter operation but
had difficulty in demonstrating that they could
apply this knowledge to changing raw water
quality and subsequently to achieving optimized
performance goals. Water treatment understand-
ing was identified at 14 of the 69 plants. A lack
of understanding means that the operators did not
have the basic knowledge of water treatment,
which would make successful implementation of a
process control testing program impossible. Since
operator limitations in applications of concepts and
limitations in water treatment understanding are
mutually independent in identifying CPE factors,
these results can be combined, which indicates
that 85 percent of the plants had operational limi-
tations that adversely impacted performance.
Seven of the top 12 factors were related to design
aspects of the facility. While most flocculation,
sedimentation, and filtration processes were found
to be of adequate size during the major unit proc-
ess evaluation, limitations associated with these
unit processes contributed to their identification as
factors limiting performance. Sedimentation proc-
esses were projected to be marginal at 39 plants,
typically due to the inability to treat seasonal high
raw water turbidities, improper placement of efflu-
ent weirs that disrupted quiescent settling, and
effluent conditions that resulted in floe shear prior
to filtration. Problems such as backwash limita-
tions, improperly maintained rate-of-flow control-
lers, and disrupted support gravels and
underdrains contributed to filtration being identi-
fied as a performance limiting factor. Flocculation
problems were typically related to marginal vol-
ume, lack of multiple stages, fixed speed mixer
drives that made tapered flocculation impossible,
and inoperative mechanical equipment.
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Disinfection was also identified as a top factor
limiting performance. As noted, the adoption of
final regulations by the states may affect the
future results in identifying the ranking of this fac-
tor. Although plants may be able to improve con-
tact time by installing baffles, some plants may
require major capital improvements (e.g., new con-
tact basins, alternate disinfectant capabilities) to
accommodate the need for greater contact time
and/or reduced DBF levels.
Process flexibility, process controllability and ulti-
mate sludge disposal/backwash water treatment
were the other design factors that were consis-
tently identified. The identification of these fac-
tors was usually.attributed to plants that were not
equipped with the capability to add chemicals at
different points in the plant, were unable to oper-
ate processes in different configurations (e.g.,
series or parallel), were unable to measure or con-
trol flows through processes, or lacked appropriate
backwash water treatment facilities that limited
the plant's ability to backwash filters based on
performance degradation.
It was projected that implementing minor modifica-
tions, reducing peak flows, and improving process
control could provide alternatives at individual
facilities to avoid major modifications. Ideally,
CIAs implemented at these facilities could be used
to implement these alternatives. If the CTA
results were unsuccessful, a construction alterna-
tive could be more clearly pursued. It was con-
cluded that, despite the high ranking for design
factors, immediate construction of major plant
modifications was not indicated or warranted.
Two administrative factors, policies and inade-
quate plant staff, were among the top factors
identified. Plant administrative policies were
observed in 29 CPEs to be detrimental to perform-
ance. Typically, these administrators were not
aware of the significance of finished water quality.
For example, most were unaware of the impact on
public health of even short-term excursions from
high quality treated water. Additional items con-
tributing to the identification of these factors
included plant administrators that: 1} were not
aware of plant resources or training requirements,
2) could not relate the impact of their decisions on
plant performance and thus public health, 3) had
policies related to minimizing production cost at
the expense of performance, and 4) maintained
plant staffing at levels too low to support process
control requirements.
Eighteen of the 69 plants had a plant staff size
considered to be too small to properly operate and
monitor the treatment plant. This was considered
to be critical with respect to the projected need for
increased levels of process control and monitoring
required to achieve optimized performance goals.
Staffing limitations were felt to be especially criti-
cal for plants that were being operated for periods
without staff on-site and without alarm and shut-
down capability triggered by performance parame-
ters.
It was interesting to note that insufficient
resources were not found to be a significant factor
limiting performance of the water plants evaluated
despite the fact that lack of resources is a widely
publicized reason for noncompliance of small sys-
tems. Insufficient funding was identified in only
13 of 69 plants. Furthermore, in only 4 of the 13
plants where insufficient funding was identified, it
was considered to be a major factor limiting per-
formance. Numerous utilities had sizable capital
reserve funds, and those that did not often had
water rates set at unreasonably low levels. It was
projected that resources could be made available
to address operations limitations and to implement
minor design modifications at these facilities.
Time would be required in follow-up CTAs at these
utilities to gain administrative support and under-
standing for reallocation or development of
resources, but the option to achieve this support
was projected to be viable.
The lack of identification of any significant mainte-
nance-related factors is also important to note.
Maintenance-related factors were assessed as
having a lessor or minor impact relative to the
operations and administrative factors. Only 2 of
the 69 CPEs had a maintenance factor identified
as having a major impact on performance. At both
facilities, total neglect was apparent. At these
facilities administrative policies that were contrary
to supporting the integrity of the infrastructure
were also identified as factors.
6.2.3 Summary of CPE Findings
• The flocculation, sedimentation and filtration
processes in 92 percent of the plants were
projected to have adequate capacity to handle
plant peak instantaneous operating flows.
• Construction would be required for 13 percent
of the plants if only post-disinfection were
96
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allowed, and baffling of existing clear-wells is
not sufficient. Disinfection capabilities are
dependent on the final interpretation and
implementation of the disinfection regulations
by individual states.
Operations factors limited performance in 60
percent of the CPEs performed. This finding,
coupled with the fact that 92 percent of the
existing facilities were assessed to have ade-
quate capacity to meet turbidity removal
requirements, indicates that addressing opera-
tions factors could significantly improve water
treatment plant performance.
Although design factors represent half of the
top factors identified, it was projected that
these deficiencies could be satisfactorily
addressed in many cases by utilizing minor
modifications, decreasing plant flows, and
improving process control/operations.
Administrative factors were identified as hav-
ing a significant impact on plant performance.
Training of plant administrators must be an
integral part of implementation of programs to
optimize performance.
Administrators must assure that adequate pro-
visions have been made to deal with compla-
cency and reliability issues. These issues are
prevalent for systems using stable high quality
source waters where administrators and staff
may be lulled into a false sense of security by
over-relying on the source water to protect
them from performance degradation. Adminis-
trators need to encourage operational staff to
maintain skills relative to proper process con-
trol for changing source water quality.
Impacts due to plant size only affected the
amount of time that it took to conduct the
actual CPE. Larger plants required more time
to conduct the interview process due to larger
operational and administrative staffs, yet the
approach was still applicable to large systems.
On-site performance assessments indicated
that reported finished water turbidities were
often not representative of true performance.
Continuous recording of turbidity from each fil-
ter is considered essential to provide operators
with enough information to minimize excur-
sions in treated water turbidities.
Numerous plant-specific impacts on perform-
ance were identified during the conduct of the
CPEs:
• Lack of attention to filter rate control
devices resulted in deteriorated filter per-
formance.
• Lack of attention to the impact of flow
rate changes on operating filters resulted
in deteriorated filter performance.
• Starting dirty filters resulted in deterio-
rated filter performance.
• Filter performance immediately following
backwash was often unsatisfactory and
posed a significant health threat during
this critical operational period. Improved
operational practices, chemical condition-
ing of the backwash water, or use of
existing filter-to-waste provisions are
alternatives to address this negative
impact on filter performance.
• Adequate process control was only prac-
ticed in just over half of the plants where
CPEs were conducted.
1 Decreased flows and increased operating
time offer a significant alternative to con-
struction of new facilities for many small
water treatment plants.
• Exit meetings with the administrators
were identified as one of the major advan-
tages of the CPE over other surveys and
inspections.
6.3 Results of Comprehensive Technical
Assistance Projects
CTAs have been conducted at eight facilities to
establish that plant performance
improved. Seven facilities achieved improved per-
formance without major capital expenditures.
remaining CTA, and improved performance was
not documented at this facility.
facilities where successful CTAs were imple-
mented, four were completed when the goal was
SWTR. The remaining three facilities were com-
pleted when the performance objective was the
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optimized performance criteria outlined in
Chapter 2. It is noted that performance results of
all seven of the facilities where CTAs were
completed would meet the proposed turbidity
performance objectives outlined in the IESWTR.
(3)
The potential in existing facilities to achieve cur-
rent and proposed regulatory requirements is a
viable alternative for many water treatment utili-
ties. More importantly, the CTA component has
demonstrated that optimized performance goals
can be achieved at small to medium-sized facilities
without major construction. This capability should
be utilized, especially at high risk facilities, as
described in Chapter 3, to obtain maximum benefit
toward public health protection from existing
plants.
6.4 References
When an NTIS number is cited in a reference, that
reference is available from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650
1. Surface Water Treatment Rule From Federal
Register, Vol. 54, No. 124. June 1989. U.S.
Parts 141 and 142, Rules and Regulations, Fil-
tration/Disinfection.
2. USEPA. November 3, 1997. National Primary
Drinking Water Regulations: Disinfectants and
Disinfection Byproducts; Notice of Data
Availability; Proposed Rule. Fed. Reg.,
62:212:59338.
3. USEPA. November 3, 1997. National Primary
Drinking Water Regulations: Interim Enhanced
Surface Water Treatment Rule; Notice of Data
Availability; Proposed Rule. Fed. Reg.,
62:212:59486.
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Chapter 7
The Future: Changing Regulations and
Ne w Optimization Challenges
7.1 Introduction
This handbook presents procedures for optimizing
filtration plant performance for particle removal. It
is the intent of this chapter to discuss how, even
when a water system has used these procedures
and attained the desired turbidity performance
goals, the challenges of plant optimization will
continue. Water systems face other regulatory
requirements, both current and future, that they
will need to consider as they maintain the opti-
mized turbidity performance achieved through use
of the CCP procedures. While water systems
must comply with a wide variety of drinking water
regulations, this chapter will focus on a series of
regulations known as the microbial-disinfectants/
disinfection by-product regulations (M-DBP) which,
from a regulatory perspective, represent one of the
biggest challenges facing water suppliers over the
next several years. It is not intended that this
chapter discuss the detailed requirements of these
regulations or serve as the definitive resource on
the technical issues around these regulations.
Most of these regulations have not been finalized;
and, when finalized, USEPA will provide detailed
guidance on the specific requirements and the
relevant technical information needed to comply.
7.2 Background on M-DBP Regulations
The M-DBP regulations were the result of a regula-
tory negotiation process (Reg-Neg) in 1993 (1,2,3)
between the USEPA and representatives of the
water supply industry over mutual concerns about
the possible health impacts of microbial pathogens
and DBPs. The following concerns were identified
during discussions to identify ways to minimize
health risks:
1. The adequacy of microbial control, especially
for Cryptosporidium, under the current Surface
Water Treatment Rule (SWTR).
2. The possibility that, if systems were to reduce
levels of disinfection to control DBPs, microbial
control could be compromised.
Control of microbial pathogens and DBPs were
linked together in these regulatory discussions
because of a fundamental concern that operational
changes to control DBPs could potentially lead to
changes in treatment. These changes could
adversely impact microbial pathogen control,
Regulations for microbials and DBPs, therefore,
needed to simultaneously consider the inherent
tradeoff of public health risks associated with
changing treatment practices for reducing levels of
DBPs along with the potential risks of lower
microbial pathogen control. In order to balance
these "risk-risk" tradeoffs, separate regulations for
microbial pathogens and DBPs are to be promul-
gated with effective dates set such that water sys-
tems will have to comply with both regulations at
the same time.
The original M-DBP Reg-Neg agreement included
the following:
. A "Stage 1 " DBP regulation that would apply
to all systems. This regulation would initially
apply to systems with a population of
> 10,000. Systems with a population of
< 10,000 would have extended compliance
dates.
. A "Stage 2" DBP regulation to evaluate the
need for further reductions in DBPs when more
health effects and occurrence information
becomes available.
. An "Interim" Enhanced SWTR (IESWTR) for
PWSs > 10,000 to address improvements in
microbial control and risk-risk trade-off issues
related to the "Stage 1 " DBP regulation which
would be implemented at the same time.
. A "Long Term" ESWTR (LTESWTR) that
would apply to PWSs C 10,000 which would
be implemented when they are required to
comply with the "Stage 1 " DBP regulation.
This regulation could also include enhance-
ments that would also apply to the large sys-
tems.
99
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During the Reg-Neg process there was also
agreement that additional data and research was
needed on occurrence, treatment capabilities, and
health effects of both microbials and DBFs to pro-
vide a sound technical basis for these regulations.
These issues were to be resolved by:
• An Information Collection Rule OCR) to collect
occurrence and treatment information to
evaluate possible components of an IESWTR,
LTESWTR, and "Stage 2" DBP regulations.
• Additional research, including health effects
studies, to support regulatory development.
In July 1994, USEPA proposed a "Stage 1 " DBP
regulation (4) and an IESWTR (5) which reflected
the 1992-93 negotiations. The ICR was promul-
gated in May 1996 (6) with data collection start-
ing in July 1997 and continuing for 18 months.
Based on this schedule, the ICR data will not be
collected, validated and available for regulation
development until January 2000.
In August 1996 congress passed amendments to
the Safe Drinking Water Act (SDWA) (7) that
included the following statutory deadlines for
USEPA to promulgate the M-DBP regulations:
- IESWTR and "Stage 1" DBPs - November
1998
. LTESWTR - November 2000
. "Stage 2" DBPs - May 2002
These deadlines were such that it would be
impossible to use the ICR data to develop the
IESWTR and LTESWTR as intended by Reg-Neg.
In early 1997, USEPA formed the M-DBP Advisory
Committee under the Federal Advisory Committee
Act (FACA) to help the Agency meet the new
SDWA deadlines. This resulted in an agreement in
principle that formed the basis for the Notice of
Data Availability (NODA) for the "Stage 1 " DBP (8)
and the IESWTR (9) to supplement the 1994
proposal for these regulations. Based on com-
ments on the 1994 proposals and these NODAs,
the IESWTR will be promulgated in November
1998. USEPA plans to promulgate the LTESWTR
in 2000 in order to meet the SDWA mandate with
a compliance date that will correspond to the
"Stage 1 " DBP regulations for PWSs < 10,000.
Even though the LTESWTR applies to PWSs
< 10,000, it could include refinements for larger
systems.
USEPA also plans to promulgate a "Long Term 2"
ESWTR (LT2ESWTR) at the same time that the
"Stage 2" DBP regulation is promulgated in order
to address risk-risk trade-offs.
7.3 M-DBP Requirements Relative to
Optimized Performance Goals
The discussions above indicate that by the year
2002 USEPA will have promulgated several differ-
ent SWTRs and DBP regulations, and water sys-
tems will be facing compliance. It is also apparent
that these regulations are interrelated such that
water systems will need to consider the impacts of
treatment process changes from the perspective of
both regulations. The remainder of this section
will discuss some of the major areas where special
consideration of optimization with respect to
M-DBP will need to be considered.
7.3.7 Treatment Technique Turbidity
Requirements
Figure 7-I presents a historical perspective of tur-
bidity goals and regulations. The original SDWA
passed by congress in 1974 (1 0) required USEPA
for the first time to regulate turbidity. A require-
ment of 1 NTU was established, which was to be
measured at the combined plant effluent based on
one sample per day. There was also a maximum
turbidity level of 5 NTU. In 1989 the original
SWTR (1 1) was promulgated that lowered the
combined plant turbidity levels to 0.5 NTU based
on samples every four hours, but retained the
maximum of 5 NTU.
The 1997 Microbial and Disinfectants/Disinfection
Byproducts (M-DBP) Federal Advisory Committee
meetings, resulted in the collection, development,
evaluation, and presentation of substantial data
and information related to turbidity control. The'
FACA committee recommended that the turbidity
performance requirements be changed such that
the combined filter effluent limit be reduced to
0.3 NTU and that the maximum value be reduced
to 1 NTU. In addition, the Committee recom-
mended that systems conduct individual filter
monitoring and that exceptions reports be pro-
vided to states under specific circumstances,
namely:
100
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1. any individual filter with a turbidity level
greater than I.O NTU based on two
consecutive measurements fifteen minutes
apart; and
2. any individual filter with a turbidity level
greater than 0.5 NTU at the end of the first
four hours of filter operation based on two
consecutive measurements fifteen minutes
apart.
The Committee also recommended that if an indi-
vidual filter has turbidity levels greater than
1.0 NTU based on two consecutive measurements
fifteen minutes apart at any time in each of three
consecutive months, the system should be
required to conduct a self-assessment of the filter,
utilizing as guidance relevant portions of guidance
issued by the Environmental Protection Agency for
Comprehensive Performance Evaluation (CPE).
Also, if an individual filter has turbidity levels
greater than 2.0 NTU based on two consecutive
measurements fifteen minutes apart at any time in
each of two consecutive months, the system
should be required to arrange for the conduct of a
CPE by the State or a third party approved by the
State.
The IESWTR is scheduled for promulgation in
November 1998, at which time the specific
turbidity requirements and provisions will be
available. EPA will issue detailed guidance at that
time on the relevant technical information needed
to comply with the rule. Both the L TE1ES WTR
and L T2ESWTR are in pre-developmental stages.
Figure 7-1 also shows the turbidity goal of
0.1 NTU that was discussed in previous chapters
of this handbook and how regulated turbidity lev-
els are approaching this long held turbidity goal.
This is not intended to predict that future regula-
tions will be set at the 0.1 NTU level, but to
encourage plants to pursue the 0.1 NTU perform-
ance goals outlined in this handbook, as a way to
assure regulatory compliance on a combined plant
basis.
7.3.2 Removal/lnactivation Requirements
The original SWTR required water systems to pro-
vide a minimum of 3-log removal/inactivation of
Giardia cysts. State regulatory agencies that
received primacy from USEPA were given broad
latitude in how plants would meet this require-
ment, including the option to increase the
removal/inactivation requirements for water sys-
tems that may have higher levels of cysts in their
source water. Rule guidance stated that properly
operating filtration plants could be expected to
remove between 2.0 to 2.5-log of Giardia cysts,
and this removal could be credited against the
3-log requirement. The remaining log removal was
to be achieved with disinfection. Log removal
credits for various disinfectants and operating
conditions were provided in tables of disinfectant
concentration (C) multiplied by the contact time
(T).
A major impetus for the IESWTR was that Crypto-
sporidium was not regulated under the original
Figure 7-1. Historic perspective of turbidity goal and regulations.
1.5
SDWA (1 .0 NTU)
SWTR (0.5 NTU)
IESWTR (0.3 NTU;
"Stag
Optimized Performance Goal (0.1 NTU)
1" DBFs
ESWTR
;Stag
e 2" DBFs
"^ ** Is. O f
£ I I ? ?
10 eg
o>
o>
«* %
101
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SWTR. This was of concern since chlorine is not
an effective disinfectant against Cryptosporidium,
and the impact of other disinfectants (e.g., ozone,
chlorine dioxide) has not been well established.
The 1997 M-DBP Federal Advisory Committee
recommended adoption of a 2-log Cryptosporidium
removal requirement for all surface water systems
that serve more than 10,000 people and are
required to filter. The committee also recom-
mended that systems which use rapid granular
filtration (direct filtration or conventional filtration
treatment - as currently defined in the SWTR) and
meet strengthened turbidity requirements would
be assumed to achieve at least a 2-log removal of
Cryptosporidium. Systems which use slow sand
filtration and diatomaceous earth filtration and
meet existing SWTR turbidity performance
requirements (less than 1 NTU for the 95th per-
centile or alternative criteria as approved by the
State) also would be assumed to achieve at least a
2-log removal of Cryptosporidium.
The IESWTR is scheduled for promulgation in
November 7998, at which time the specific
removal requirements and provisions will be
available. EPA will issue detailed guidance at that
time on the relevant technical information needed
to comply with the rule. Both the L TE1ESWTR
and L T2ES WTR are in pre-developmental stages.
7.3.3 DBF Maximum Contaminant Levels
(MCLs)
DBFs were first regulated in 1979 (12) when an
MCL of 0.10 mg/L was established for the sum of
four trihalomethanes (THM), which applied to only
those water systems serving populations
> 10,000 persons. As discussed above, the pur-
pose of the M-DBP regulations is to reduce the
health risk for these compounds and other DBFs
by promulgation of disinfectant and disinfectant
by-product (D/DBP) regulations to be implemented
in two stages. The NODA for Stage 1 of the
D/DBP rule has lowered the MCL for THMs and a
new MCL has been added for the sum of five addi-
tional compounds called haloacetic acids (HAA5).
The NODA also contains maximum residual disin-
fectant levels (MRDLs) permitted in the distribution
system.
Fundamental control procedures for THMs and
HAAs remain essentially the same and include:
. Removal of natural organic matter (NOM),
which are precursors, in the raw water.
• Altering the point of disinfectant addition.
Reducing the amount of disinfectant used.
(NOTE: This may not be feasible because of
microbial backstop requirements.)
• Switching to alternate disinfectants,
In conventional treatment, NOM is removed by a
coagulation/adsorption mechanism accomplished
by changing the coagulation process to enhance
the removal of these organics. A potential con-
flict exists from the standpoint of plant process
meet the optimized turbidity performance goals
described in this handbook may not be compatible
goals. Some research has shown, however, that
enhanced coagulation conditions also achieved
ies have evaluated the impacts of enhanced
coagulation on filterability which may be more of a
problem.
Altering the plant's disinfection practices to meet
the DBF MCLs, either through changing the point
of disinfectant addition or lowering the disinfectant
dose, can potentially also lead to other types of
conflicts. When disinfectants are added ahead of
can also provide additional important benefits
(e.g., enhance the coagulation process for tur-
bidity removal, enhance iron and manganese con-
trol, etc.) along with meeting the plant's CT
requirements. Lowering pre-disinfection doses to
reduce DBF formation, therefore, could result in
turbidity performance problems or higher levels of
iron and manganese in the finished water. The
major consideration in changing disinfection prac-
tices to control DBFs, however, is to assure that
the change will not result in compliance problems
with state SWTR disinfection and the IESWTR
microbial backstop requirements. The major unit
process evaluation described in Chapter 4 presents
disinfection conditions (e.g., chlorine residual, pH)
that are necessary to achieve desired inactivation
levels.
If none of the above process control changes are
sufficient to control DBFs, then the utility may
have to consider alternate disinfection including
102
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ozone, chlorine dioxide, or chloramines. Ozone
and chlorine dioxide will result in major modifica-
tions to the treatment plant and will require the
design and installation of new treatment processes
and equipment. Chloramines, depending on the
plant, may be considered a modification that
would be addressed as part of a CTA.
7.3.4 Enhanced Coagulation Requirements
The Stage 1 DBF regulations, proposed in the
NODA for the first time require surface water sys-
tems that use conventional treatment or softening
to remove a specified minimum percentage of the
total organic carbon (TOO from their raw water
using a process called enhanced coagulation. TOC
removal is required because other DBFs besides
THMs and HAAs are formed when disinfectants
react with a NOM, measured as TOC. The occur-
rence and health effects of these unidentified
DBFs are unknown at this time. The intent of this
part of the proposed regulation is to control the
formation of unknown, as well as known, DBFs by
requiring that a minimum percentage of NOM in
the raw water, measured as TOC, is removed by
the plant.
The percentage of TOC removal required is based
on the TOC and alkalinity levels of the plant's raw
water. These TOC removal requirements are
broken down into nine different percent TOC
removal categories. They are presented in a table
for three different alkalinities and raw water TOC
levels.
Plants that cannot meet the specified percent TOC
removals will follow a "Step 2" procedure to
determine what levels of TOC removal are "rea-
sonable and practical" to achieve. The plant uses
this information to request an alternative TOC
removal requirement from its primacy regulatory
agency.
The "Step 2" procedures consist of special jar
tests to determine the maximum percent TOC
removal that they can achieve by incremental
increases in coagulant dose. Coagulant dose is
increased in 10 mg/L increments until a specified
pH level (depending on the raw water alkalinity) is
achieved. Residual TOC levels in each jar are then
measured, and an analysis is made of the "point of
diminishing return" (POOR). The POOR is defined
as when a 10 mg/L increase in coagulant does not
decrease the residual TOC by more than 0.3 mg/L.
This percentage TOC removal would then be con-
sidered "reasonable and practical" and would be
used in discussions with the primacy agency rela-
tive to giving the plant an alternate enhanced
coagulation requirement.
When a water system meets one of a variety of
conditions it may be exempted from the enhanced
coagulation part of the regulation. It was recog-
nized that only the humic fraction of the raw water
TOC is amenable to removal by enhanced coagula-
tion. Plants, therefore, with high levels of non-
humic TOC may not be able to meet any of the
enhanced coagulation removal requirements and
could be exempt from this part of the regulations.
Plants can assess the amount of humics in their
raw water by measuring its specific UV absorb-
ance or SUVA. SUVA is defined as the UV
absorbance divided by the dissolved organic car-
bon (DOC). SUVAs of <3 L/mg-cm represent
largely non-humic materials, and SUVAs in the
4-5 L/mg-cm range are mainly humic. SUVA val-
ues can also be used to request exemption from
the regulations and to determine POOR.
Plants may find that achieving desired TOC
removal will require some significant changes in
plant process control procedures. Enhanced
coagulation typically requires that additional
coagulant and/or acid is added to depress the pH
to a point where the TOC is removed in the
coagulation process. As with control of DBFs,
potential conflicts exist from the standpoint of
plant process control procedures. Chemical feed
rates needed to meet the turbidity performance
goals in this handbook may not be compatible with
those needed for enhanced coagulation.
7.3.5 Microbial Backs top
As discussed above, the Reg-Neg agreement
required that the M-DBP regulations would balance
the risk-risk tradeoffs between control of microbial
contaminants and DBFs. Control of DBFs was not
to result in any decrease in microbial protection.
Since alteration of disinfection practices is one
way of controlling DBFs, major concern was
expressed during the 1997 FACA process regard-
ing reduced disinfection capability. An approach
was needed to make sure that water systems did
not change disinfection practices to control DBFs
and decrease microbial protection.
The approach that resulted from these discussions
was the microbial backstop. As part of the micro-
bial backstop requirements, water systems will be
103
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required to prepare a disinfection profile when they
approach specified levels of THMs and HA As. A
disinfection profile is a historical characterization
of the system's disinfection practices over a period
of time using new or "grandfathered" daily moni-
toring data. A disinfection profile consists of a
compilation of daily Giardia log inactivation values
based on SWTR CT tables. These calculations will
be based on daily measurements of operational
data (disinfectant residual concentration(s); con-
tact time(s); temperature(s); and, where neces-
sary, pH(s)).
The second part of the microbial backstop
requirement is benchmarking, which quantifies the
lower bound of the system's current disinfection
practices. It is intended that water systems take
the results from the profiling and work with the
state regulatory agency to evaluate changes in
disinfection practices which could be used to con-
trol DBFs so that these changes result in no sig-
nificant decreases in microbial protection. Bench-
marking is only required if a PWS intends to make
a significant change to its disinfection practices
such as moving the point of disinfection, changing
disinfectants, changing the disinfection process, or
any changes the state considers significant.
Part of the concern that led to the microbial back-
stop was based on data that showed water plants
with widely varying disinfection levels. Figure 7-2
shows a profile where it is apparent that the plant
was not operating their disinfection systems at
any common baseline. Day-to-day variations
above the state disinfection requirement could be
caused by plants not determining their required CT
based on seasonal changes in water temperature
and pH and/or not having close operational control
over the actual CT provided by the plant. An
example would be not changing the applied disin-
fectant dose to respond to changes in the required
CT, disinfectant demand, and/or operating flow.
Plants could also be adding disinfectant for other
treatment issues such as to control Fe, Mn, algae,
and/or taste and odor. The microbial backstop
would require water systems to understand in
more detail how much disinfectant they are
applying on a daily basis, and it would force them
to make rational decisions on why they are adding
higher levels of disinfectant above that required for
the state's disinfection requirements.
7.4 Summary
Water systems pursuing optimization for public
health protection must remain vigilant concerning
the ramifications of new and changing regulations.
Those plants that have met the optimized
performance goals defined in this handbook should
be well positioned to take those regulations in
stride and continue to meet the ever more
stringent challenges facing the water industry.
Figure 7-2. Example of disinfection profile daily variations in log inactivation.
Why the Difference?
"Improper Operational Practices
•Fe and Mn Control
Taste and Odor
•Algae
State Disinfection Requireme
104
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7.5 References
1. Means, E.G. and SW. Krasner. February
1993. "D-DBP Regulation: Issues and Ramifi-
cations." Journal A WWA, 85:2:68. Denver,
CO.
2. Pontius, F.W. September 1993. "Reg-Neg
Process Draws to a Close." Journal AWWA,
85:9:18. Denver, CO.
3. Roberson J.A., J.E. Cromwell, S.W. Krasner,
M.J. McGuire, D.M. Owen, S. Regli, and R.S.
Summers. October 1995. "The D/DBP Rule:
Where did the Numbers Come From?" Journal
A WWA, 87:10:48. Denver, CO.
4. USEPA. July 29, 1994. National Primary
Drinking Water Regulations: Enhanced Surface
Water Treatment Requirements; Proposed
Rule. Fed Reg., 59:145:38832.
5. USEPA, July 29, 1994. National Primary
Drinking Water Regulations: Disinfectants and
Disinfection By-products; Proposed Rule. Fed.
Reg., 59:145:38668.
6. USEPA. May 14, 1996. National Primary
Drinking Water Regulations: Monitoring
Requirements for Public Drinking Water Sup-
plies. Fed. Reg., 61:94:24353.
7. US Code. August 6, 1996. Title XIV of the
Public Health Service Act (The Safe Drinking
Water Act) as Amended by Public Law 104-
182.
8. USEPA. November 3, 1997. National Primary
Drinking Water Regulations: Disinfectants and
Disinfection By-products; Notice of Data
Availability; Proposed Rule. Fed Reg.,
62:212:59338.
9. USEPA. November 3, 1997. National Primary
Drinking Water Regulations: Interim Enhanced
Surface Water Treatment Rule; Notice of Data
Availability; Proposed Rule. Fed Reg.,
62:212:59486.
10. USEPA. December 4, 1975. National Interim
Primary Drinking Water Regulations. EPA-
570/9-76-003.
11 USEPA. June 29, 1989. Filtration and Disin-
fection: Turbidity, Giardia lamblia, Viruses,
Legionella, and Heterotrophic Bacteria; Final
Rule. Fed. Reg., 54:124:27486.
12. USEPA. November 29, 1979. National Pri-
mary Drinking Water Regulations: Control of
Trihalomethanes in Drinking Water; Final Rule.
Fed. Reg., 44:231:68624.
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Chapter 8
0 ther CCP Considerations
8.1 Introduction
The purposes of this chapter are to present train-
ing requirements for persons wanting to conduct
CCP activities and to identify parameters that can
be used by CCP providers or recipients of CCP
services to assure quality control of the CCP
approach. In addition, a brief discussion is pre-
sented concerning the applicability of the CCP
approach to other optimization and compliance
activities that a utility may be required to achieve
now or in the future.
8.2 Developing CCP Skills
8.2. 1 CPE Training Approach
In Chapters 4 and 5 the type of training and expe-
rience necessary to implement CPEs and CTAs
was discussed. In addition to these basic skill
requirements, it has been demonstrated that
hands-on training is very effective for developing
CCP skills in interested parties. For conducting
CPEs, a training approach has been formalized and
demonstrated with several state drinking water
program personnel. The training consists of train-
ees participating in a one-day seminar that pro-
vides instruction and workshop opportunities for
them to become familiar with the CPE terminology
and approach. This seminar is followed by three
actual CPEs where the trainees gain CPE skills
through progressive training that is facilitated by
experienced CPE providers. The roles of the CPE
provider and trainee are described in Table 8-1.
During the first CPE, the trainees are involved in
the data collection and special study activities but
are largely in an observation role during the kick-
off meeting, interview, and exit meeting activities.
Involvement in the remaining two CPEs is gradu-
ally increased such that by the time the third CPE
is conducted the trainees are responsible for all of
the activities. CPE provider observation and
involvement take place only when necessary.
This approach has proven to be very effective in
transferring CPE skills to trainees. Currently, the
training process is scheduled over a four to six-
month period. It is noted that in addition to the
training activities, a quality CPE must be provided
to the water utility. Because of this expectation,
the number of participants that can be trained
while still completing the CPE must be limited to
about four to six people.
8.2.2 CTA Training Approach
Participation in the CPE training, as described in
the previous section, is considered a prerequisite
to participation in CTA training. Training for per-
sonnel to implement CTAs has followed a format
similar to the one used for CPE training. CTA pro-
viders can be used to progressively transfer skills
to trainees through the conduct of actual CTA
activities. The difficulty with this approach is the
fact that the CTA typically occurs over a 6 to 18-
month period. Also, routine telephone contact
with the facility can only be effectively imple-
mented by one person. The current training
approach consists of CTA provider and trainee
involvement at site visits, with the provider sup-
plying technical assistance to a designated trainee
who maintains routine contact with the utility per-
sonnel. The CTA provider utilizes telephone calls
and exchange of materials (e.g., telephone
memos, operations guidelines, plant data) to main-
tain trainee involvement. Although the approach
and time commitment limit the number of trainees
involved, effective transfer of CTA skills has been
achieved.
A key component of CTA training is the emphasis
on providing problem solving and priority setting
capability to the utility staff. Using this approach,
the trainees must learn not to "lead with their
troubleshooting skills" but rather to recognize how
to utilize situations to enhance utility priority set-
ting and problem solving skills. This does not
mean that CTA providers do not give technical or
administrative guidance when necessary; they only
use these activities when they are absolutely nec-
essary to accomplish the long term transfer of
capability to the utility staff and administration.
107
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Table 8-1. Training Approach to Achieve Transfer of CPE Skills
Training Activity
CPE Provider Role
Trainee Role
CCP Seminar
(1 day)
Present CPE seminar
Participate in seminar
First CPE
(3-4 days)
• Conduct kick-off meeting
. Facilitate data collection
Conduct special studies
• Conduct interviews
. Facilitate information exchange with team
• Prepare exit meeting materials
• Conduct exit meeting
. Facilitate feedback session with team
• Prepare final report
Observe kick-off meeting
Participate in data collection
Participate in special studies
Observe interviews
Review exit meeting materials
Observe exit meeting
Review final report
Second CPE
(34 days)
, Conduct kick-off meeting
, Facilitate data collection
. Conduct special studies
. Conduct interviews
Facilitate information exchange with team
> Finalize exit meeting materials
Facilitate exit meeting
Facilitate feedback session with team
Review draft report
Participate in kick-off meeting
, Participate in data collection
Participate in special studies
> Participate in interviews
> Prepare exit meeting materials
> Participate in exit meeting
Prepare final report
Third CPE
(34 days)
. Observe kick-off meeting
> Participate in data collection
, Observe special studies
. Participate in interviews
, Review exit meeting materials
. Observe exit meeting
Facilitate feedback session with team
, Review draft report
> Conduct kick-off meeting
. Facilitate data collection
Conduct special studies
> Conduct interviews
Facilitate information exchange with team
> Prepare exit meeting materials
> Conduct exit meeting
> Prepare final report
8.3 Quality Control
It is important for CCP providers and recipients of
CCPs to be aware of appropriate CCP applications,
expectations of the process, and maintenance of
program integrity, Maintaining the integrity of the
CCP approach can best be accomplished by fol-
lowing the protocols described in this handbook.
However, to assure effective and consistent CCP
results, quality control considerations have been
developed and are presented in this section.
8.3.1 CPE Quality Control Guidance
Table 8-2 presents a checklist for CPE providers
and recipients to assess the adequacy of a CPE
relative to the guidance provided in this handbook.
Some of the key areas are discussed in more detail
in this section.
A challenging area for the CPE provider is to main-
tain the focus of the evaluation on performance
(i.e., public health protection). Often, a provider
108
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will tend to identify limitations in a multitude of
areas which may not be related to optimized per-
formance criteria. Typical areas may include poor
plant housekeeping practices, lack of preventive
maintenance, or lack of an operation and mainte-
nance manual. Limitations in these areas are
easily observed and do not challenge the capability
of the operations staff. While they demonstrate a
thoroughness by the provider to identify all issues,
their identification may cause the utility to focus
resources on these areas and to ignore areas more
critical to achievement of optimized performance
goals. The evaluator should be aware that a utility
will have the tendency to take the CPE results and
only address those factors that are considered
relatively easy to correct without consideration of
priority or the inter-related ness of the factors.
Table 8-2. Quality Control Checklist for
Completed CPEs
Findings demonstrate emphasis on achievement of
optimized performance goals (i.e., performance
emphasis is evident in the discussion of why priori-
tized factors were identified).
Lack of bias associated with the provider's back-
ground in the factors identified (e.g., all design fac-
tors identified by a provider with a design back-
ground or lack of operations or administrative fac-
tors identified by the utility personnel conducting a
CPE).
Emphasis in the CPE results to maximize the use of
existing facility capability.
All, components of the CPE completed and docu-
mented in a report (i.e., performance assessment,
major unit process evaluation, identification and pri-
oritization of factors, and assessment of CTA appli-
cation).
Less than 15 factors limiting performance identified
(i.e., excessive factors indicates lack of focus for
the utility).
Specific recommendations are not presented in the
CPE report, but rather, clear examples that support
the identification of the factors are summarized.
Identified limitations of operations staff or lack of
site specific guidelines instead of a need for a third
party-prepared operation and maintenance manual.
Findings address administrative, design, operation
and maintenance factors (i.e., results demonstrate
provider's willingness to identify/present all perti-
nent factors).
When implementing a CPE, it is important to
understand that specific recommendations involv-
ing plant modifications or day-to-day operational
practices should not be made. For example, direc-
tion on changing coagulants or chemical dosages
is not appropriate during the conduct of a CPE.
There is a strong bias for providers to give specific
recommendations and for recipients to want spe-
cific checklists to implement. CPE providers
should focus their observations during the evalua-
tion on two key areas: 1) identification of factors
limiting the facility from achieving optimized per-
formance goals and 2) provision of specific exam-
ples to support these factors.
Another significant challenge in conducting an
effective CPE is the tendency for providers to iden-
tify limitations that are non-controversial rather
than real factors that may challenge utility person-
nel's roles and responsibilities. For example, it is
often easy to identify a design limitation, since the
utility could not be expected to achieve optimum
performance with inadequate facilities. It is much
more difficult to identify "lack of administrative
support for optimized performance goals" or an
operators' "inability to apply process control con-
cepts" as the causes of poor performance. Failing
to appropriately identify these difficult factors is a
disservice to all parties involved. A common result
of this situation is the utility will address a design
limitation without addressing existing administra-
tive or operational issues. Ultimately, these
administrative and operational issues remain and
impact the utility's ability to achieve optimized per-
formance. The challenge to properly identify the
true factors can best be achieved by the CPE pro-
vider focusing on the "greater good" (i.e., achiev-
ing sustainable water quality goals). Understand-
ing this concept allows the CPE provider to pres-
ent the true factors, even though they may not be
well received at the exit meeting.
8.3.2 GTA Quality Control Guidance
Table 8-3 presents a checklist for CTA providers
and recipients to assess the quality of a CTA. A
review of the components of the checklist would
be a good way to ensure that the integrity of the
CTA approach has been maintained. Some of the
key components are discussed further in this
section.
109
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Table 8-3. Quality Control Checklist for
Completed CTAs
Plant specific guidelines developed by utility staff.
Demonstrated problem solving skills of utility staff.
Demonstrated priority setting skills of utility admini-
stration and staff.
Tenacity of plant staff to pursue process changes
when optimized performance goals are exceeded
(i.e., filtered water turbidity begins to increase and
approaches 0.1 NTU).
Utility policy established by administrators to
achieve optimized performance goals.
Demonstrated communication between utility man-
agement and staff.
Training plan that supports front line operators to
be capable of achieving performance goals under all
raw water conditions. For very stable raw water
conditions the training plan should include capability
to address "what if" situations (e.g., avoid compla-
cency).
Adequate staffing or alarm and shut down capa-
bility to ensure continuous compliance with opti-
mized performance goals.
Adequate funding to support maintaining optimized
performance goals.
Clear direction for utility personnel if optimized per-
formance goals are not achieved.
Trend charts showing unit processes meeting opti-
mized performance objectives over long time peri-
ods despite changes in raw water quality.
Quality control for a CTA is more easily measured
than for a CPE, since the bottom line is achieve-
ment of unit process and plant optimized perform-
ance goals. Consequently, a graphical depiction of
performance results can be used to demonstrate
the CTA endpoint. In some cases the desired per-
formance graph cannot be achieved because of
physical limitations (e.g., a Type 2 unit process
was not able to perform as desired); however, the
utility officials can then proceed with confidence in
addressing the limiting factor.
Some attributes of a successful CTA are subtle
and difficult to measure. However, they ensure
that the integrity of the process is maintained after
the CTA provider is gone. Long term performance
can only be achieved by an administrative and
operations staff that have established water
quality goals and demonstrated a commitment to
achieve them. A successful CTA will result in a
tenacious staff that utilize problem solving and
priority setting skills in their daily routine. Plant
staff recognition of the role that they play in pro-
tecting the public health of their customers can
create a strong professional image. These attrib-
utes can often be difficult to assess, but they are
obvious to the utility personnel and the CTA pro-
vider if they have been developed during the CTA.
One of the most difficult challenges for a CTA
provider and utility personnel is to address the
issue of complacency. Complacency can occur for
all parties if stable raw water quality exists or if
stable performance occurs due to the efforts of a
few key personnel. It is important that a CTA
provider and the utility personnel look beyond the
comfort of existing good performance and develop
skills to address the scenarios that could upset the
current stable situation.
8.4 Total System Optimization
As current and future regulations continue to be
implemented, the challenges facing the water
treatment industry will also expand. One of the
challenges will be the integration of optimizing par-
ticle removal with other, sometimes competing,
optimization goals (e.g., control of disinfection by-
products, corrosion control). The CCP approach
has been successfully applied to wastewater
treatment, water treatment (i.e., microbial protec-
tion), and ozone applications for water treatment
(1,2). Based on this success, it is anticipated that
the CCP approach can be adapted to new drinking
water regulations and associated requirements.
Future areas for optimization, such as watershed
management, balancing disinfection by-product
control with microbial protection, and controlling
water quality in distribution systems, are believed
to be suitable for development utilizing the CCP
approach. This overall approach is called total
system optimization, and the concept is intended
to be developed through additional publications
that will enhance this handbook. Table 8-4 pre-
sents a summary of total system optimization con-
siderations for drinking water utilities.
The USEPA is funding the development of a Cen-
ter for Drinking Water Optimization that will focus
research on the impacts of new regulations on
water treatment plant process control. Results of
this research, coupled with field applications and
110
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Table 8-4. Total System Optimization Considerations for Drinking Water Utilities
Optimization
Area
Watershed/
Source Water
'rotection
Disinfection By-
products
.ead
Copper
7/yp tosporidium
Control
3lant Recycle
Distribution
System
Performance
Focus
Microbial
Protection
THMs
HAAs
Bromate
Lead and
Copper
l/licrobial
Protection
Microbial
Protection
Microbial
Protection
Optimization Activities
Monitor for sources of microbial
contamination
Develop watershed protection
program
Remove/address known sources
of contamination: develop
pollution prevention partnerships
Develop emergency response
plans
Reduce current level of
prechlori nation
Relocate prechlorination to post
sedimentation
Increase TOO removal
Change disinfectant type; change
from chlorine to chloramines for
maintaining residual
Corrosion control; feed corrosion
inhibitor, adjust pH to achieve
stable water
Achieve optimization criteria
defined in Chapter 2
Stop recycle practices
Stop recycle to plant; discharge
wastewater to sewer or obtain
permit to discharge to receiving
water
Provide treatment of recycle for
particle removal
Develop monitoring program:
include routine, construction, and
emergency coverage
Maintain minimum disinfectant in
system; consider booster
stations, changing from chlorine
to chloramines; eliminate dead-
end zones
Develop unidirectional flushing
program
Cover treated water storage
reservoirs
Develop storage tank inspection
program, provide vent screens,
routine cleaning procedure
Maintain turnover rate in storage
tanks based on monitoring results
Possible Treatment Conflicts
Reduction in prechlorination
reduces preoxidation effects and
reduces particle removal
Increased TOC removal increases
sludge production/impacts
facilities
Lowering disinfectant residual
causes regrowth
Lowering oxidant level increases
T&O
Lowering disinfectant residual
reduces disinfection capability
Increased pH levels could reduce
available CT for disinfection
. Discharge of water treatment'
residuals to sewer impacts
wastewater treatment capacity
Optimizing storage tank turnover
impacts disinfection capability
111
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Table 84. Total System Optimization Considerations for Drinking Water Utilities (Continued)
Groundwater
Treatment
Microbial
Protection
Eliminate contaminants from
entering wells (i.e.. well head
protection program)
Monitor for microbial
contamination
Provide disinfection (e.g.,
establish policy to achieve virus
inactivation, CT)
evaluations, will be used to integrate total system
optimization components with the CCP approach.
8.5 References
1. DeMers, L.D., K.L. Rakness, and B.D. Blank.
1996. Ozone System Enerav Optimization
Handbook. AWWARF, Denver, CO and Elec-
tric Power Research Institute Community Envi-
ronmental Center, St. Louis, MO.
2. Hegg, B.A., L.D. DeMers, and J.B. Barber.
Handbook:
Retrofittina POTWs.
1989.
EPA/625/6-89/020, USEPA Center for Envi-
ronmental Research Information, Cincinnati,
OH.
112
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Appendices
113
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Appendix A'
Data Collection Spreadsheets and Macros for
the Partnership for Safe Water
Section 1 Background on the Data Collection Spreadsheets and Macros
Section 2 Selecting the Spreadsheet and Macros for Your Applications
Section 3 Loading the Spreadsheet and Macros
Section 4 Running the Macro Self-Test
Section 5 Entering Performance Data
Section 6 Activating the Macros
Section 7 Printing Spreadsheet Output
Section 8 Important Rules to Remember When Using the Spreadsheets and Macros
Figure A-l Example performance assessment data collection spreadsheet output
Table A-l File Designations for Various Software Spreadsheets - Single Sample Per Day Format
Table A-2 File Designations for Various Software Spreadsheets - Multiple Sample Per Day Format
1 Developed by Eric M. Bissonette, Technical Support Center, USEPA.
115
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Section 1 - Background on the Data
Collection Spreadsheets and Macros
Spreadsheets have been prepared to assist utility
formance data (raw, settled, and filtered turbidity)
of the Self-Assessment.
spreadsheets will also form the basis of reports to
the Partnership activities.
The spreadsheets have been developed to capture
turbidity data from raw water, sedimentation basin
effluent and filter effluent, but can be used to
manage repetitive data of any kind (e.g., particle
counts in certain size ranges, turbidity data from
an individual filter, chemical dosages and flows)
from any point in the process for up to 365 days
worth of data. Macros have been written to gen-
erate frequency distributions, on a monthly and
annual basis, to help evaluate trends and summa-
rize the large amounts of data. Graphics capabili-
ties of the spreadsheets are also built in to auto-
matically plot trend charts and frequency distribu-
tions. There are also capabilities for generating
summaries of the data to report as background
information or on an annual basis. Other data
summaries within the capabilities of each spread-
sheet software version could be generated as well.
The spreadsheets accommodate up to six values
per day or one value per day.
Interpretation of data from the performance
assessment is addressed in Chapter 4 of this
handbook. In general, turbidity fluctuations in raw
water being propagated through the sedimentation
basin and filter effluents could indicate inadequate
process control or physical limitations in one or all
of the major unit treatment processes. The trend
charts and frequency distributions can indicate
variability of turbidity and trends in performance.
Individual filter turbidity or particle data can be
examined to determine if individual filters are not
performing up to expectations,
Each spreadsheet has memory requirements of
1 MB of RAM, of which 250 KB at minimum has
been allocated as expanded or enhanced memory.
Systems with computers incapable of allocating
memory above 640 KB should restrict data entry
to one turbidity value per day for six months
worth of data per spreadsheet. If memory con-
straints persist, memory management techniques
specified for individual software versions should
be utilized.
Execution of the spreadsheet macros to analyze
data, generate trend graphs, and calculate monthly
percentile distributions is straightforward. The
following instructions for loading selected spread-
sheets, entering data, activating macros, and
printing output were, however, generated assum-
ing that users have some familiarity with spread-
sheet software packages. Specific instructions for
entering data are discussed in Section 5. Macro
execution for LOTUS 123 Release 2.4 spread-
sheets is approximately 15 minutes on a 486
25 MHz computer for twelve months of data. The
WINDOWS spreadsheet macros take four minutes
to complete once activated.
The spreadsheets are designed such that upon
macro execution the user may simply print the
previously defined range containing the percentile
tables and graphs and submit this as the baseline
report (please see the attached example Perform-
ance Assessment Data Collection Spreadsheet
Output). Users requiring assistance in data entry
and macro execution should contact Eric
Bissonette of USEPA/OGWDW Technical Support
Division at (5 13) 569-7933 or e-mail requests for
assistance to bissonette.eric@epamail.epa.gov.
Users are encouraged to continue to use the
spreadsheets to collect and analyze data after the
baseline collection effort has been completed.
Simply copy the provided spreadsheet with a new
filename and continue data entry as defined for
each spreadsheet type. Continued long term use
of the data management spreadsheets will assist
users in the conduct of Phase III - the self-assess-
ment/self-correction phase and Phase IV - the third
party assessment/correction phase of the Partner-
ship for Safe Water, as well as provide fundamen-
tal input to a plant process control testing pro-
gram.
PLEASE NOTE: Never work from the diskette con-
taining the master copy of the data collection
spreadsheets. Folio w instructions for copying the
appropriate spreadsheet and files described in Sec-
tion 3 and work from that copy.
116
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Section 2 - Selecting the Spreadsheet and
Macros for Your Applications
Spreadsheets with macros have been developed to
execute in LOTUS 123 Release 2.4 for DOS and
5.0 for WINDOWS, EXCEL Release 4.0 and 5.0 for
WINDOWS, and QUATTRO PRO Release 5.0 for
WINDOWS software systems. The spreadsheets
will accommodate data entry of a single value per
day or up to six values per day. Files preceded by
the letter "d" represent spreadsheets capable of
accommodating one sample per day. Files pre-
ceded by the number "4" represent spreadsheets
capable of accommodating six samples per day (a
sample every four hours). Select the files corre-
sponding to your application and data entry needs
from the following table and proceed to Section 3.
Section 3 - Loading the Spreadsheet and
Macros
The Spreadsheet files with macros have been
stored in a compressed mode on the diskette and
must be "exploded" to create the "working" files
listed in Section 2. Files may be "exploded" as
follows:
. Start from the drive prompt of the desired
directory (e.g., C:\123\PA_data\).
• Copy the appropriate "compressed" file for
your spreadsheet software application as
specified in Section 2 from the Spreadsheet
Master Diskette to a directory resident on your
hard drive.
Table A-l. File Designations for Various Software Spreadsheets - Single Sample Per Day Fdrmat
Single Component
Spreadsheets
Compressed Files
Working Files
External Format
Files
External Macros
for DOS
LOTUS 123 2.4
D_L24.EXE
D-1 23R24.WK1
D-1 23R24.FMT
None
for WINDOWS
LOTUS 123 5.0
D_L5W.EXE
D-1 23R5W.WK4
None
None
EXCEL 4.0 or 5.0
D_XCL.EXE
D_EXCEL4.XLS
None
MACRO 1 .XLM
QUATTRO PRO 5.0
D_QP.EXE
D_QUTPRO.WB1
None
None
Table A-2. File Designations for Various Software Spreadsheets - Multiple Sample Per Day Format
Multiple
Component
Spreadsheets
Compressed Files
Working Files
External Format
Files
External Macros
for DOS
LOTUS 123 2.4
4_L24.EXE
4J23R24.WK1
4_1 23R24.FMT
None
for WINDOWS
LOTUS 123 5.0
4_L5W.EXE
4J23R5W.WK4
None
None
EXCEL 4.0 or 5.0
4_XCL.EXE
4_EXCEL4.XLS
None
MACR04.XLM
QUATTRO PRO 5.0
4_QP.EXE
4_QUTPRO.WB1
None
None
117
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• For non-WINDOWS applications, simply type
the compressed filename with the .EXE exten-
sion and press return (e.g., type D_L5W.EXE
at the C:\123\PA data> prompt and press
return).
For WINDOWS applications, select Bun from
the File submenu and type the compressed
filename with the .EXE extension and click on
OKAY.
When control of the keyboard is returned to the
user:
• Copy the required "External" format and macro
files and "DATA1.WK1 " from the Master
Diskette to the directory containing the newly
created "working" file.
• Return to the menu or WINDOWS screen.
• Select the icon or menu option to enter the
spreadsheet package (e.g., click on the
LOTUS 123 Release 5.0 icon). (NOTE:
WYSIWYG needs to be invoked for the
LOTUS 123 Release 2.4 spreadsheets.)
• Open the newly created "working" file as
specified in Section 2 and save the file under a
new file name. Please note: The EXCEL
spreadsheets require that the macro files
"MACRO1 .XLM" or "MACR04.XLM" are
opened in addition to the spreadsheet file.
Once the macro file has been opened, utilize
the HIDE feature under the WINDOW com-
mand to redisplay the data entry worksheet.
• Proceed to Section 4 to run the macro self-test
or Section 5 to begin entering performance
data.
Section 4 - Running the Macro Self-Test
Should users have concerns about the compati-
bility of the spreadsheets and macros and their
spreadsheet software package, they should con-
duct a self-test of the macro. The self-test output
will resemble the attached Example Performance
Assessment Data Collection Spreadsheet Output.
Run the self-test as follows:
. Open the "working" file created in Section 3
(refer to Section 2 table file name) and
save/rename the file.
• For a single component (one sample per day)
self-test: Copy range B1 ..B365 from the file
"DATA1 .WK1 " to cell B49..B413. Go to the
Single Component portion of Section 5 and
proceed.
• For a multiple component (up to six samples
per day) self-test: Copy range D1 ..1365 from
the file "DATA1 .WK1 " to Cell D49..I413. Go
to the Multiple Component portion of
Section 5 and proceed.
. Activate the macro using steps specified in
Section 6.
. Print output using steps specified in Section 7.
The printed output should resemble the attached
Example Performance Assessment Data Collection
Spreadsheet Output. Please note: Outputs gener-
ated will vary slightly due to differences in the
spreadsheet software package being used. Should
the macro prove inoperable, reinstall the files from
the Master Diskette and repeat the process and/or
refer to Section 8 prior to requesting assistance.
Section 5 - Entering Performance Data
Prior to entering data, users should set the work-
sheet recalculation mode to manual to decrease
data entry and macro execution time. To begin
the data entry process:
• Open or Retrieve the working and external files
specified in Section 3.
• Enter the appropriate Utility/Plant specific
information in cells F39.. F44.
• Enter the last two digits of the start year in
cell B40 (e.g., 94 for 19941.
• Enter the start month in cell B41 (e.g., 7 for
July!.
• Data entry should always begin on the first of
each month and include the entire month.
• All graphical and percentile table computations
key on the entered dates. Therefore, no dates
should be left blank.
118
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For Single Component Spreadsheets (for use when
entering one value per day):
• The formula residing in cell A50 will automati-
cally increase the date entered in A49 by one
day. Copy cell A50 to A51, A52, A53 and so
on to the end of the year or the data entry
period.
• After the column of dates has been generated
in Column A, begin entering data (turbidity or
particle counts, etc.) one value at a time in cell
B49, B50, B51, etc. until all data has been
entered. Note: The data entry section of the
spreadsheet is highlighted in yellow. Skip cells
when no data exists for those days.
. Do NOT enter data in Column A.
For Multiple Component Spreadsheets (for use
when entering six values per day - e.g., 4-hour
data):'
• The formula residing in cell A50 will automati-
cally increase the date entered into A49 by
one day. Copy cell A50 to A51, A52, A53
and so on to the end of the year or the data
entry period.
• The formula residing in cell B49 calculates the
maximum value of the six daily entries. Copy
cell B49 to B50, B51, B52 and so on to the
end of the year or until the end of the data
entry period. Note: Until data is entered in
Columns D through I, the value in Column B
will show an "ERR" message. Ignore this
message.
• After the column of dates and formulas for
daily maximums has been generated in
Columns A and B, begin entering the 40 hour
data (turbidity or particle counts, etc.) one
value at a time in cells D49 and E49 and F49
and G498 and H49 and 149, etc. until all data
has been entered. Note: The data entry sec-
tion is highlighted in yellow. Skip cells when
no data exists for those days.
• Do NOT enter data in Column A or B.
• After all data has been entered the worksheet
should be saved with a new file name. This
will protect the data in the unlikely event of
error during execution of the macro.
Section 6 - Activating the Macros
To activate the macros when using:
. LOTUS 123 Release 2.4 for DOS, press the
ALT and F3 keys simultaneously. Highlight A
and press C Enter> or . Note: the
LOTUS 123 Release 2.4 spreadsheets generate
graphs during execution, and users must press
c Return> or when graphics appear
on the screen to proceed through execution.
These graphs summarize previous entries and
may be confusing during the first entry
process.
LOTUS 123 Release 5.0 for WINDOWS or
QUATTRO PRO Release 5.0 for WINDOWS,
position and click the mouse button on any
button contained within the spreadsheet
labeled "Run Macro."
EXCEL Release 4.0 or 5.0 for WINDOWS,
press the CTRL and A keys simultaneously.
Section 7 - Printing Spreadsheet Output
To print the percentile tables and graphs generated
during macro execution using:
. LOTUS 123 Release 2.4, invoke the
WYSIWYG add-in and print the previously
defined range by pressing then
selecting and after the sys-
tem has been configured to the user's printer.
If the WYSIWYG add-in is unavailable, users
should'generate and print the graph PIC files
Filtyear.PIC and Filtprob.PIC using the LOTUS
Printgraph procedures.
. LOTUS 123 Release 5.0 or QUATTRO PRO
Release 5.0 or EXCEL Release 4.0 or 5.0, fol-
low printing techniques specified for
WINDOWS applications by clicking on a printer
icon (which will print the previously defined
range) or select PRINT from the File submenu
(and select "previously defined range") when
the system requests a printing option. Users
may have to adjust margins to accommodate
individual applications in order to print output
to a single sheet of paper.
119
-------
Section 8 - Important Rules to Remember
When Using the Spreadsheets and
Macros
. Please remember that the spreadsheets and
macros were developed and tested to operate
sions specified in Section 2. The spreadsheets
other release versions. Users have had suc-
for DOS spreadsheet in a Release 2.3 ope rat-
to execute the WINDOWS QUATTRO PRO 5.0
ALT and F2 in lieu of depressing the RUN
WINDOWS applications. Please remember that
tested by the Partnership for Safe Water soft-
ware development group.
. The only DOS version of the spreadsheets is
LOTUS 123 Release 2.4. All other spread-
sheets are WINDOWS applications.
• Make certain that the correct spreadsheet and
macros are used for analyzing the appropriate
data based on the number of daily samples
(e.g., 1 sample per day versus 6 samples per
day).
Do NOT enter more than 12 months of data on
any spreadsheet. Users should create a sepa-
rate spreadsheet for each 12 months worth of
data. The spreadsheet will inaccurately depict
percentiles in the table and on the probability
graph when data entry exceeds one year.
• Do NOT expect the percentile tables and trend
and percentile graphs to update with correct
values until the macros for the spreadsheets
have been executed. Prior to macro execu-
tion, the spreadsheet percentile tables and
graphs contain data generated from the test
data.
• When using the EXCEL spreadsheets do NOT
open both external macro files simultaneously.
Use only the designated macro for the appro-
priate spreadsheet.
• Individual spreadsheets need to be created for
handling raw, settled, and filtered/finished
data. Memory constraints preclude accommo-
dating all sampling points within a single
spreadsheet.
• Table and graph titles, when working in
WINDOWS applications, may be edited by
simply positioning the mouse pointer on the
appropriate cells and double clicking the cell.
This enters the edit mode.
• When using the DOS spreadsheet, the titles
may be edited by depressing the F2 key in the
appropriate cell and typing in the changes.
Users must enter the graph mode to modify
the chart/graph titles.
120
-------
Figure A-l. Example performance assessment data collection spreadsheet output.
Daily Filtered Water Turbidity
Percantlk Yearly Jurv94 Jul-94
50 0,03 0,02 0,02
75 0.04 0,02 0.03
90 0.07 0.03 0.04
9S 0.11 0.06 0.06
96 0,14 0,05 0.06
97 0.16 0.07 0.09
88 0.19 NA IA
99 0.20 NA IA
Av( 0.04 0.02 0.02
Mil 0.01 0.01 0,01
Ma: 0.54 0.07 0.09
RSI 121.9% S7.3-J 07.4%
Aug-94
0.02
0.02
0.02
0.03
0.03
0.03
NA
NA
0.02
0,01
0.03
27.9*
Sep. 94 Oct-94
O.OZ 0.02
0.02 0.03
O.03 0.04
0,03 0.07
0,03 0.07
0,07 0.07
A
A
NA N
NA N
0.02 0.03
0.01 O.O1
0.07 0.07
50.3% 43.2%
Nov-94
0.02
0,05
0.09
0.24
0.24
0.54
A
A
0.08
O.O2
O.S4
170.5%
Deo-94
0.03
0.08
0.08
0.11
0,11
0.12
NA
NA
0.04
0.01
0,12
71.1%
Jan-05
0.04
O.OS
0.06
0.07
0,07
0.08
NA
NA
0.04
0.03
O.OS
29.8%
Feb-95
0.03
0.03
0.04
0,04
0.04
O.OS
NA
NA
0.03
O.O2
0.05
28.8%
Mor-35
0.04
0.10
0.17
o.ia
0.1 a
0.40
NA
NA
0.07
0.02
0.40
104.44
Apr- 95
0.06
0.12
0.19
0,20
0,20
0.22
IA
IA
0.09
0.02
0.22
72 7%
MW-SS
0,03
0.04
0.04
0.08
0.06
0.07
IA
IA
0.03
0.01
0,07
40.0%
Filtered Water Turbidity
0.5 -•
5 0.4
2
£ 0.3 ••
S
€
£ 0.2 -
1
OA " 1 1 1, i 1, ll
. juiuL^JuJ^
1 1 I 1 I 1 I I i 1
Start Year 94 365 = Total Days
Month 6 12,00 = Total Months
Day 1
Utility Nom<
Plant Name
if HI
111
1
(PVu
i 1
Probability Dietribution of All Data
0 6
0,5 •
2 0.4
5
£• 0.3
•n
'.5
a 0.2
r-
0.1 -
0
j
f
\
^f
—
0 10 20 30 40 50 60 70 60 90 100
Percent of time turbidity values < = X
>
Rant Street Address
Plant Cfty. state. Zip
Plant Contact Name
Plant Prmn«
-------
Appendix B
Drinking Water Treatment Plant (D WTP) Advisor Software
Development of the DWTP Advisor
The DWTP Advisor is a computer software appli-
cation designed as an "expert system" to provide
assistance in the evaluation of drinking water
treatment plants. The program was based on the
source document Interim Handbook: Optimizing
Water Treatment Plant Performance Usina the
Composite Correction Program Approach (1). The
Interim Handbook is the predecessor document to
this handbook, of which this appendix is a part.
The software was developed to assist personnel
responsible for improving the performance of
existing water treatment plants in order to achieve
compliance with the 1989 SWTR.
The system consists of two major components:
Major Unit Process Evaluation and Performance
Limiting Factors. These two component parts were
designed to work together. The evaluator, there-
fore, cannot choose to use only one of the pro-
gram's components. In addition, the evaluator
cannot modify the loading values, some of which
are currently outdated. The software leads the
evaluator through a series of questions and pro-
vides responses based on the experience and
judgment of a group of experts that were used to
delineate the logic for the program. The complex-
ity of the multiple interrelated factors limiting per-
formance and the uniqueness of individual plants
makes production of an expert system with broad
scale application difficult. This coupled with the
fact that the program has not been updated for
several years, should make persons considering
use of the software aware of these inherent
limitations.
Even though an expert system like the DWTP
Advisor would theoretically have many uses, its
current level of development limits its usefulness
in conducting CPEs. Persons familiar with the fun-
damental CCP concepts and who understand the
limitations of the software, however, may find it a
useful tool.
Technical Information
Hardware Requirements
The DWTP Advisor requires an IBM AT or com-
patible computer with the following components:
• A hard disk with at least 5.0 megabytes of
free space
• At least 640 Kbytes of RAM (560,000 bytes
user-available)
• A high density floppy disk drive (5.25" 1.2 MB
or 3.5" 1.4 MB)
• DOS version 3.0 or higher
• A printer (EPSON compatible) configured as
system device PRN (optional)
If you installed the DWTP Advisor, but are unable
to run the program, you may need to check your
computer's memory configuration. Although your
computer may have the minimum memory
required, memory resident programs may use
some of this memory. "User-available" memory is
the amount of memory remaining after the oper-
ating system and memory resident programs are
loaded. If memory resident programs are installed
and adequate memory is not available for the
DWTP Advisor, an error message will appear on
the screen when you attempt to run the program.
If this occurs, memory resident programs should
be disabled (e.g., by editing your computer's con-
figuration files, config.sys and autoexec.bat) and
your computer rebooted before running the sys-
tem. To check the status of your computer's disk
and available memory, run the MS-DOS CHKDSK
program by typing CHKDSK and pressing
. For more information, see the MS-DOS
manual that came with your computer or consult
your PC support staff.
Software Specifications
The DWTP Advisor has been developed using sev-
eral commercially available software tools. The
system interface was developed using Turbo
Pascal 6. The "reasoning" or evaluating portion of
the system uses the expert system shell 1ST
Class. The system also consists of data files in
dBase.dbf format.
123
-------
Contents of the System
The DWTP Advisor package includes one double-
sided, high density disk and complete User Docu-
mentation.
A copy of the Water Advisor Software may be
obtained by contacting:
ORD Publications (G-721
26 West Martin Luther King Drive
U. S. Environmental Protection Agency
Cincinnati, Ohio 45268-I 072
Telephone: 513-569-7562
Fax: 5 13-569-7566
Ask for: Drinking Water Treatment Plant
Advisor Software: 625/R-96/02
124
-------
Appendix C
Major Unit Process Capability Evaluation
Performance Po tentiaf Graph Spreadsheet Tool
for the Partnership for Safe Water
Section 1 Background on the Major Unit Process Capability Evaluation
Section 2 The Performance Potential Graph Spreadsheet Tool
Section 3 Selecting the Appropriate Spreadsheet for Your Application
Section 4 Loading the Spreadsheet
Section 5 Entering Plant Information/Data
Section 6 Printing Spreadsheet Output
Section 7 Important Rules to Remember When Using the Performance Potential Graph
Spreadsheet Tool
Figure C-l Example performance potential graph output for LOTUS 123 files.
Figure C-2 Example performance potential graph output for EXCEL and QUATTRO
PRO files.
Figure C-3 Example performance potential graph data entry section for all files.
Figure C-4 Performance potential graph data entry guide.
Table C-l Various Software Spreadsheets - The Designations for Performance Potential Graph
Table C-2 Major Unit Process Evaluation Criteria
125
-------
Section 1 - Background on the Major Unit
Process Capability Evaluation
Water treatment plants are designed to take a raw
water source of variable quality and produce a
consistent, high quality finished water using mul-
tiple treatment processes in series to remove tur-
bidity and prevent microbial contaminants from
entering the finished water. Each treatment proc-
ess represents a barrier to prevent the passage of
microbial contaminants and particulates in the
plant. By providing multiple barriers, any microor-
ganisms passing one unit process can possibly be
removed in the next, minimizing the likelihood of
microorganisms passing through the entire treat-
ment system and surviving in water supplied to
the public.
The performance potential graph (see Figures C-l
and C-2) is used to characterize capabilities of
individual treatment processes to continuously
function as a barrier for removing particulates and
harmful pathogens. Each of the major unit proc-
esses is assessed with respect to its capability to
consistently contribute to an overall plant treated
water quality of less than 0.1 NTU turbidity during
peak flows. Specific considerations are given only
to process basin size and capability under optimum
conditions. Limitations in process capability due
to minor deficiencies or incorrect operation (e.g.,
degraded baffles which allow short-circuiting or
improper process control) do not contribute to
development of the performance potential graph.
These operational or minor modification limitations
are addressed during the evaluation of the other
aspects of the treatment plant conducted as part
of the Partnership for Safe Water self-assessment
procedures.
Specific performance goals for the flocculation,
sedimentation, filtration, and disinfection unit
processes are used when developing the perform-
ance potential graph. These include settled water
turbidities of less than 2 NTU and filtered effluent
turbidities of less than 0.1 NTU. Capabilities of
the disinfection process are assessed based on the
CT values outlined in a USEPA guidance manual
for meeting filtration and disinfection require-
ments. Rated capacities are determined for each
of the unit processes based on industry standard
loading rates and detention times with demon-
strated capability to achieve specific unit process
performance goals. These evaluation criteria are
defined in Table C-2 of this appendix. The result-
ing unit process rated capacities are compared to
the peak instantaneous operating flow for the
treatment plant. Any unit process rated capacities
which do not exceed the plant's peak instantane-
ous operating flow are suspect in their ability to
consistently meet desired performance goals that
will maximize protection against the passage of
microbial contaminants through the treatment
plant. Specific interpretation of the results of the
performance potential graph are discussed in Sec-
tion 3 of the Partnership for Safe Water self-
assessment procedures. It is important that the
Figure C-l. Example performance potential graph
spreadsheet output for LOTUS 123 releases.
Major Unit Process Evduation
Performance Potential Graph
Flow IMGD)
2.5
7.5 10 12.5 15 17.5 20
Unit Processes
Flocculation
Sedimentation
Filtration
Disinfection
Pre & Post
Post Only
1 I 1 I 1 'I
9.60 i
14.04 |
18.82
16.82
8.98 ,
\ \
^14.5 MOD
,
m
Figure C-2. Example performance potential graph
spreadsheet output for EXCEL and QUATTRO PRO
releases.
M4<* Urit PTOOMI EmluMion
Pwfonrano* Prt«nttsl Qnph
22.5
20
17.6
Rocoulition SedimtrrtBtlon
Filtration Dwiirftttton: Pie t Post
Unh Pracc««t
726
-------
evaluator recognize that the guidance provided by
this computer software should not exceed the
evaluators' judgement in projecting unit process
capability. Options to change loading rate projec-
tions to values different from those provided are
available and should be considered if data or the
evaluators' experience justifies the modification.
Section 2 - The Performance Potential
Graph Spreadsheet Tool
Spreadsheets have been generated to assist Utility
Partners in creating the performance potential
graph required for Section 3 for use in the Part-
nership for Safe Water self-assessment proce-
dures. Generating the performance potential graph
requires opening the appropriate spreadsheet file
and entering specific physical plant information in
the defined cells (see Figure C-4). A performance
potential graph will be generated automatically.
Rated capacities for each unit process are gener-
ated from user-defined criteria as well as from cri-
teria defined in Table C-2 and discussed in Section
3 of the Partnership for Safe Water self-
assessment procedures. The user may print a
hard copy of the performance potential graph by
following steps defined in Section 6 of this
appendix.
Users requiring expanded instructions for entering
appropriate information in the spreadsheet cells
should refer to Figure C-3. Should users require
additional assistance in preparing a performance
potential graph using the spreadsheet, please con-
tact Eric Bissonette of USEPA/OGWDW Technical
Support Division at (513) 569-7933.
Section 3 - Selecting the Appropriate
Spreadsheet for Your Application
Performance Potential Graph Spreadsheets have
been developed in LOTUS 123 Release 2.4 for
DOS and 5.0 for WINDOWS, EXCEL Release 4.0
and 5.0 for WINDOWS, and QUATTRO PRO
Release 5.0 for WINDOWS software systems.
Select the files corresponding to your application
and data entry needs from Table C-l and proceed
to Section 4.
Table C-l. File Designations for Various Software
Spreadsheets - Performance Potential Graph
Performance
Potential
Graphs
Working Files
External
Format Files
for DOS
LOTUS
123 2.4
PPG.WK1
PPG.FMT
tor WINDOWS
LOTUS 123
5.0
PPG.WK4
None
EXCEL 4.0 or
5.0
PPGXLC-XLS
None
QUATTRO
PRO 5.0
PPGQP.WB1
None
Section 4 - Loading the Spreadsheet
. Copy the required working file and external
format file from the Master Diskette to a direc-
tory resident on the hard drive of your com-
puter. Do NOT work from the files contained
on the Master Diskette.
• Enter your spreadsheet software by selecting
the appropriate icon or menu option (e.g., click
on the LOTUS 123 Release 5.0 icon). (Note:
WYSIWYG needs to be invoked for the LOTUS
123 Release 2.4 spreadsheets.)
. Open the working file as specified in Section 3
and save the file under a new file name.
Section 5 - Entering Plant Information
Each spreadsheet contains a data entry section
and a chart which depicts the resulting individual
unit process rated capacities. The LOTUS 123
spreadsheets generate a performance potential
graph with the unit process rated capacities char-
acterized by horizontal bars (see Figure C-l). Con-
trarily, the EXCEL and QUATTRO PRO perform-
ance potential graphs characterize the unit process
capacities by vertical bars (see Figure C-2). The
data entry sections are identical for the LOTUS
123, EXCEL, and QUATTRO PRO performance
potential graph files (see Figure C-3).
• Begin entering appropriate physical plant data
in cells B31..B71 and E32..E69. Figure C-4
contains in-depth description of the acceptable
entries for each of the cells in the spreadsheet.
. The entered physical plant data will appear in
blue. Cells containing black values are calcu-
lated from data entered in other cells and can-
not be modified.
127
-------
Figure C-3. Performance potential graph data entry guide.
Peak Instantaneous Flow
What is the peak flow in MGD at any instant through the treatment plant? This peak flow is based on historical records and pumping capacity.
(See Section 3 of the Self-Assessment for further discussion.1
N)
00
P red is infection
Presedimentation
Presed. Basin Volume
Presed. Basin Baffling
Predisinfection Practiced
Temperature (*C)
PH
Predisinf. Residual (mg/L)
Predisinf. Application Paint
Required CT
Predisinfection Volume
Effective Predisinf. Volume
Flocculation
Basin Volume
Temperature (°C)
Mixing Stages
Assigned
Rated Capacity
Sedimentation
Basin Volume
Surface Area
Basin Depth
Operation Mode
Process Type
Tubes Present
Does the plant have and utilize a presedimentation basin? Enter Yes or No.
What is the volume (in gallons) of the presedimentation basin(s)?
What is the baffling condition of the presedimentation basin(s)? Unbaffled Poor Average Superior Impacts effective volume calculation regarding
Predisinfection contact time based on estimated T10to T ratios.
Does the plant apply a disinfectant prior to the clearwell? Enter Yes or No.
What is the coldest water temperature (in degrees Celsius) at the predisinfectant application point?
What is the maximum pH at the predirinfectant application point?
What is the maximum predisinfectant residual (in mg/L)?
Where is the predisinfectant applied? Prior to the presedimentation or flocculation or sedimentation or filtration unit processes?
Using the predisinfection operating conditions (pH and Temp and required log removals), obtain the required CT value from Appendix C
of the Surface Water Treatment Rule Guidance Manual or Appendix A of the CCP Handbook.
Calculated from data entered in other areas. No entry is required here.
Calculated from data entered In other areas. Incorporates effective contact of the disinfectant based on baffling In each of the unit processes.
What Is the total volume (in gallons) Of the flocculation basin(s)?
What is the coldest water temperature (In Celsiusl that the flocculation basin experiences?
Describe the stages contained within the flocculation basin(s). Single or Multiple? No baffling or interbasin compartments equals
single-staged. All other conditions equal multiple-staged.
I Suggested detention time calculated using above information from existing conditions (see Attachment 21. No entry is required here.
Enter a detention time (in minutes). Use the suggested detention time or select one based on site-specific circumstances.
This is the rated capacity of the unit process (in MGD) calculated from the Assigned hydraulic detention time. No entry is required here.
This volume is calculated from other entered data. No entry is required here.
What is the total area (in square feet) of the sedimentation basin(s)?
What is the average depth (in feet) Of the sedimentation basin(st?
Enter Turbidity or Softening, depending an the process used. Is the process operated mainly to remove turbidity or to provide softening?
What settling process is utilized? Enter Rectangular/Circular/Contact/Lamella Plates/Adsorption Clarifier or SuperPulsator.
What type of settling tubes is present in the sedimentation basin(s|? Enter None or Vertical (>45°) or Horizontal «45°).
-------
Figure C-3. Performance potential graph data entry guide (continued).
Process SOR
Suggested I
Assigned
Rated Capacity
Filtration
Total Filter Surface Arcs
Total Number of Filters
Filters Typically In Service
Total Volume Above Filters
Media Type
Operation Mode
Raw Turbidity
Air Binding
I Suggested surface overflow rate calculated using above information from existing conditions (see Attachment 21. No entry is required hers.
Enter a surface overflow rate (SOR) (in gpm/ft2). Use the suggested SOR or select one based on site-specific circumstances.
This is the rated capacity of the unit process (in MGD) calculated from the Assigned surface overflow rate. No entry is required.
Whet is the total surface area (in square feetl of the fiiter(s)?
What is the total number of filters in the treatment plant?
What number of filters are typically in service?
What Is the total volume of water above the filter media (in gallons)?
What media configuration Is present In the filters? Enter Sand, Duel. Mixed. Deep Bed.
How are the filters operated? Enter Conventional Direct. Inline Direct.
What is ths yearly 95th percentile raw water turbidity value? Refer to the raw water turbidity spreadsheet output table.
What level of air binding is noticeable in the fliter(s|? Enter None, Moderate, High.
fO
CO
Suggested
Assigned
Rated Capacity
Loading Rate
Suggested filter loading rate calculated using above information from existing conditions (see Attachment 2). No entry la required here.
Enter a filter loading rate (in gpm/ft2). Use the suggested rate or select one based on site-specific circumstances.
This is the rated capacity of the unit process (in MGD) calculated from the Assigned filter loading rate. No entry Is required here.
Disinfection
Clearwell Volume
Effective Baffling
Temperature (°C)
pH
Disinfectant Residual (mg/L)
Required Log Inactivation
Reqd. Disinfection Log Inactivation
Pipe Distance to First User
Pipe Diameter
What is the total volume (In gallons) of the clearwell(s)?
What is the baffling condition of the clearwell(s)? Enter Unbaffled. Poor, Average, Superior. Impacts effective volume calculation
regarding disinfection contact time.
What Is the temperature (in degrees Celsiusl et the disinfectant application point?
What is the pH St the disinfectant application point?
What is the maximum disinfectant residual (in mg/U?
Enter the total number of log removals required for the plant. Enter 3 or 4 or > 4 (must be a numeric value).
Required disinfection log removals calculated from other dots. No entry is required hare.
What is the transmission distance (in feet) to the first user/customer?
What is the pipe diameter (in inches.1 of the transmission pipe?
-------
Figure C-3. Performance potential graph data entry guide (continued).
Required CT I
Using the disinfection operating conditions (pH end Tamp end required log removals), obtain the required CT value from Appendix C
of the Surface Water Treatment Rule Guidance Manual or Appendix A of the Composite Correction Program Handbook.
Effective Contact Volume
Suggested
Assigned
Post Disinfection Rated Capacity
Pre & Post Oisinf. Rated Capacity
Detention Time
Calculated from data entered in other areas. No entry is required here.
Suggested detention time calculated using above information from existing conditions (see Attachment 2). No entry is required here.
Enter a detention time (in minutes). Use the suggested detention time or select one based on site-specific circumstances.
This is the rated capacity of the unit process (in MGD) calculated from the Assigned detention time end required CTs.
No entry is required here.
This is tha rated capacity of the unit process (in MGD} calculated from the Assigned detention time and required CTs.
No entry is required here.
CO
o
-------
Figure C-4. Example performance potential graph data entry section.
CO
Plant Name
Peaklnstantaneous flow
Davenport, New Mexico |
9 (MGD)
Predrsinfection/Presedlmentation Contact
Basin Type
Basin Volume
Basin Baffling
Disinfectant Applied
Temperature (C)
fl»
Disinfect residual (nrts/L))
Required CT
Flocculation
Basin Volume
Temperature (C)
Mixing Stages
Disinfectant Applied
,fl¥
Disinfect residual (mj/L))
Respited CT
Suggested
Assigned
Rated Capacity
Sedimentation
Basin Volume
Surface Area
Basin Depth
Operation Mode
Process Type
Tubes Present
Percent Tube Area
Disinfectant Applied
PH
Disinfect residual (mg/L)
Required CT
Suggested
Assigned
Rated Capacity
Pradfa
suuuft
Poor
ozone
5
7
0,8
o.§7
200000
0.5
Multiple
None
7
Detention Time
20
20
14.40
6S"tl35
6500
14
turbidity
rectangular
Vertical
80
none
None, Pressd, Predfe, both
(gallons)
Unbaffled Poor Average Superior
None, Chlorine, Chbramines, Chlorine Dioxide, 0
See Guidance Manual Appendk C
(gallons)
Single or Multiple
None, Chlorine, Chtoramines, Chlorine Dioxide
See Guidance Manual Appendix c
(m in) HOT
(mh) HOT
MGD
(gallons)
<«2)
TO
Tuibidty or Softening
None/Rectangular/Circular/Conlact Required
LamellaPlates/AdsorpCIarifier/SuperPulsatar
None or Vertical or Horizontal Distributio
% of basin containing lubes
None, Chlorine, Chloramines. Chlorine Dioxide
See Guidance Manual Appendix C
Process SOR
1.34
1.32
gpm/ft2
gpm/ft2 Post
-14. 36 MGD Hre & Host
Filtration
Total Fitter Surface Area
Total Number of Fitters
Filters Typically in Service
Total Volume Above Fitters
Media Type
zone
Operation Mode
Raw Turbidity (NTU)
Air Binding
25UO
10
9
20000
Dual
conventional
35
None
Disinfectant Applied un tonne
Disinfect residual (mg/L)
Required CT
Suggested
Assigned
Rated Capacity
Disinfection
Cleaiwen Volume
Effective Baffling
Disinfectant Apptild
Temperature (C)
pH
Disinfectant residual (mg/L)
Required Log Inactivation
Disinfection Log Removals
i Pipe Distance to First User
Pipe diameter
Required CT
Effective Contact Volume
Suggested
Assigned
Disinfection Rated Capacity
Disinfection Rated Capacity
. 1.5
75
Loading Rate
4
4
12.S6
^oobrJoo
Unbaffled
Chlorine
5
7.5
2.5
4
1.5
1000
12
82
2Qfe87§
Detention Time
33
33
&.^8
fft2)
(gallons)
Sand Dual Mbed
DeeoBed
Conventional Direct Inline
>0
None Moderate High
Chlorine, Chloramines
None, Chlorine Dioxide
See Guidance Manual
Appendix C
gpm/ft2
gpm/ft2
MGD
(gallons)
Unbaffled Poor
Averaae Sucerior
Chlorine, Chloramines
None, Chlorine Dioxide
3 or4 or>4
(feet)
(inches)
see SWTR Guidance
Manual Appendix c'
(gallons)
(min) HOT
(mh) HOT
MGD
29,51 |MBU
-------
Table C-2. Major Unit Process Evaluation Criteria*
Flocculation Hy?raulic
Detention Time
Base
Single Stage
Multiple Stages
Temp < = 0.5"
C
Temp >0.5<>C
Temp < = 0.5°
Temo >0.5°C
20 minutes
+ 10 minutes
+ 5 minutes
+0 minutes
-5 minutes
Filtration Air Binding Loading Rate
Sand Media
Dual/Mixed Media
Deep Bed
None
Moderate
High
None
Moderate
Hiah
None
Moderate
High
2.0 gpm/ft2
1 .5 apm/ft2
1 .0 gpm/ft2
4.0 apm/ft2
3.0 apm/ft2
2.0 apm/ft2
6.0 aom/ft2
4.5 ocm/ft2
3.0 gpm/ft2
Sedimentation Surface Overflow
Rate I
Rectangular/Circular/Contact
Turbidity Mode
Softening Mode
Vertical O45") Tube Settlers
Turbidity Mode
Softening Mode
Horizontal «45°) Tube Settlers
Adsorption Clarifier
Lamella Plates
SuperPulsator
with tubes
Claricone Turbiditv Mode
Claricone Softenina Mode
Basin Death
> 14ft
12 - 14 ft
10 - 12 ft
<10ft
> 14 ft
12- 14ft
10- 12ft
<10 ft
> 14 ft
12 -14 ft
10 -12ft
<10 ft
> 14ft
12 -14 ft
10 - 12 ft
<10ft
0.7 gpm/ft2
0.6 com/ft2
0.5 - 0.6 gpm/ft2
0.1 - 0.5 apm/ft2
1.0 apm/ft2
0.75 apm/ft2
0.5 - 0,75
apm/ft7
0.1 - 0.5 apm/ft2
2.0 flpm/ft2
1,5spm/ft2
1.0-1.5 apm/ft2
0.2- 1.0 apm/ft2
2.5 apm/ft2
2.0 apm/ft2
1 .5 - 2.0 gpm/ft2
0.7 -1.5 apm/ft'
2.0 apm/ft2
9.0 apm/ft2
4.0 apm/ft2
1.5 apm/ft2
1.7 apm/ft2
1.0 apm/ft2
1.5 apm/ft2
*lf long term (12-month) data monitoring indicates capability to meet performance goals at higher loading
rates, then these rates can be used.
Renner, R.C., B.A. Hegg, J.H. Bender, and E.M. Bissonette. 1991. Handbook - Optimizing Water Treatment Plant Performance
Using the Composite Correction Program. EPA 625/9-91/027. Cincinnati, OH: USEPA.
AWWARF Workshop. 7995. Plant Optimization Workshop. Colorado Springs, CO: AWWARF.
Eastern Research Group, Inc. 1992. Water Advisor Utilizing the CCP Approach (Expert System). USEPA Work Assignment No.
7391-55. Eastern Research Group, Inc., Arlington, MA.
USEPA, AWWA, AWWARF, Association of Metropolitan Water Agencies, Association of State Drinking Water Administrators, and
National Association of Water Companies. 1995. Partnership for Safe Water Voluntary Water Treatment Plant Performance
Improvement Program.
132
-------
Each major unit process section contains a
suggested and assigned evaluation criteria cell
(e.g., the flocculation section contains a sug-
gested and an assigned hydraulic detention
time cell). The suggested loading rates, sum-
marized in Table C-2 of this appendix, for
specified situations are representative of condi-
tions in which identified unit processes have
demonstrated effectiveness in serving as a
multiple barrier in the prevention of cyst and
microorganism passage through the treatment
plant.
The actual rated capacities for each of the unit
processes are calculated from the loading rates
entered into the cells labeled "assigned loading
rates." Users must enter a value into the
assigned cell, either selecting the "suggested"
value or entering their own loading rate.
The performance potential graph contained at
the top of each spreadsheet will instantane-
ously update after each data entry. Complete
the entire data entry process prior to proceed-
ing to printing the spreadsheet output
described in Section 6.
Section 6 - Printing Spreadsheet Output
To print the performance potential graph using:
. LOTUS 123 Release 2.4 for DOS, invoke the
WYSIWYG add-in and print the previously
defined range by pressing then
selecting and after the sys-
tem has been configured to the user's printer.
If the WYSIWYG add-in is unavailable, users
should generate and print the graph PIC file
PPG. PIC, using
procedures.
the LOTUS Printgraph
LOTUS 123 Release 5.0 for WINDOWS, or
QUATTRO PRO Release 5.0 for WINDOWS, or
EXCEL Release 4.0 or 5.0 for WINDOWS, fol-
low printing techniques specified for
WINDOWS applications by clicking on a
printer icon (which will print the previously
defined range) or select PRINT from the File
submenu (and select "previously defined
range" when the system requests a printing
option). Users may have to adjust margins to
accommodate individual applications in order
to print output to a single sheet of paper.
Section 7 - Important Rules to Remember
When Using the Performance Potential
Graph Spreadsheet Tool
• Cells containing "Black" values are calculated
from other pertinent data entries and cannot
be modified because the cells have been pro-
tected.
. The actual rated capacities for each of the unit
processes are calculated from the loading rate
entered into the cells labeled "assigned loading
rates." Users must enter a value into the
assigned cell, either selecting the "suggested"
value or entering their own loading rate.
• The external format file must be copied from
the Master Diskette to the same directory as
the working file or the Performance Potential
Graph will not be visible when using LOTUS
123 Release 2.4 for DOS.
133
-------
Appendix D
CT Values for Inactivation of Giardia and Viruses
by Free CI2 and Other Disinfectants
All tables in this appendix are taken from Guidance Manual for Compliance With the Filtration
and Disinfection Requirements for Public Water Systems Using Surface Water Sources,
Appendix E, Science and Technology Branch, Criteria and Standards Division, Office of
Drinking Water, USEPA, Washington, D.C., October 1989.
I
I
135
-------
'able D-l. CT Values for Inactivation of Giardia Cysts by Free Chlorine at 0.5 °C or Laiwer
Marine
oncent ration
(mg/U
<-0.
0.8
0.8
1
1.2
1.4
1.8
1.8
2
2.2
2.4
2.8
2.8
Chlorine
Concentration
(mg/U
< -0.
0.6
0.9
1
1.2
1.4
1.6
1.6
2
2.2
2.4
2.6
2.6
pH <- 8.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
23 48 80 01 114 137
24 47 71 04 119 141
24 48 73 97 121 145
25 49 74 99 123 148
25 51 78 101 127 152
26 52 78 103 129 155
26 52 70 105 131 157
27 54 81 108 135 182
28 55 83 110 138 165
26 58 85 113 141 169
20 57 88 115 143 172
20 58 86 117 148 175
30 59 89 119 146 176
30 60 91 121 151 191
pH - 8.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
46 92 130 185 231 277
49 05 143 101 238 286
49 08 148 197 248 205
51 101 152 203 253 304
52 104 157 209 281 313
54 107 161 214 266 321
55 110 185 219 274 320
58 113 189 225 292 336
58 115 173 231 288 348
50 118 177 235 204 353
80 120 191 241 301 381
81 123 184 245 307 386
63 125 168 250 313 375
64 127 101 255 318 382
pH - 8.5
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
27 54 82 109 138 183
28 58 84 112 140 188
20 57 88 115 143 172
20 50 88 117 147 176
30 60 00 120 150 160
31 81 92 123 153 164
32 63 95 126 159 199
32 84 07 129 181 193
33 86 99 131 164 197
34 87 101 134 169 201
34 66 103 137 171 205
35 70 105 130 174 200
38 71 107 142 176 213
38 72 100 145 181 217
pH - 8.5
Log Inactivation
0.5 1.0 1.6 2.0 2.5 3.0
55 110 165 219 274 329
57 114 171 229 285 342
59 119 177 238 295 354
61 122 183 243 304 365
63 125 188 251 313 378
65 120 104 258 323 397
88 132 199 285 331 307
88 138 204 271 330 407
70 130 209 278 346 417
71 142 213 284 355 428
73 145 216 200 383 435
74 148 222 208 370 444
75 151 228 301 377 452
77 153 230 307 393 480
pH - 7.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
33 85 98 130 163 195
33 87 100 133 187 200
34 68 103 137 171 205
35 70 105 140 175 210
38 72 109 143 179 215
37 74 111 147 184 221
38 75 113 151 199 228
39 77 118 154 193 231
39 79 118 157 197 236
40 51 121 161 202 242
41 92 124 185 209 247
42 84 126 166 210 252
43 86 120 171 214 257
44 87 131 174 216 281
pH < -9.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
65 130 195 280 325 300
88 136 204 271 339 407
70 141 211 261 352 422
73 148 219 201 364 437
75 150 226 301 376 451
77 155 232 300 387 484
80 159 239 316 398 477
82 183 245 328 409 489
83 187 250 333 417 BOO
85 170 258 341 428 511
87 174 281 346 435 522
89 178 287 355 444 533
01 181 272 362 453 543
02 184 276 368 460 552
pH - 7.5
Log Inactivation
0.5 1.0 1.6 2.0 2.5 3.0
40 79 119 158 198 237
40 80 120 150 109 230
41 82 123 184 205 248
42 64 127 169 211 253
43 88 130 173 218 259
44 89 133 177 222 288
46 01 137 162 228 273
47 93 140 186 233 279
49 95 143 191 238 266
50 99 149 106 248 297
50 99 149 199 248 288
51 101 152 203 253 304
62 103 155 207 259 310
53 105 156 211 283 318
CO
O)
NOTE: CT 00.0 = CT for 3-log inactivation.
-------
Table D-2. CT Values for Inactivation of Gfardla Cysts by Free Chlorine at 5 °C
hlorine
ancantration
(tng/U
< -0,
0.8
0.8
1
1.2
1.4
1.6
1.6
2
2.2
2.4
2.8
2.9
3
Morlm
oncentratlon
Crog/l
<»o
0.8
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.8
2.8
3
pH<-6.0
Log InactivaHon
0.5 1.0 1.5 2.0 2.5 3.0
18 32 49 85 81 97
17 33 SO 87 83 100
17 34 52 69 98 103
18 35 53 70 86 105
18 38 54 71 88 107
18 38 55 73 01 100
19 37 68 74 93 111
19 38 57 78 95 114
19 3« 56 77 87 118
20 39 69 79 38 118
20 40 80 BO 100 120
20 41 81 81 102 122
21 41 62 83 103 124
21 42 83 84 105 128
pH-8.0
Log Inactlvstlon
0.5 1.0 1.5 2.0 2.5 3.0
33 66 89 132 165 188
34 89 102 136 170 204
35 70 108 140 175 210
36 72 108 144 ISO 216
37 74 111 147 194 221
38 78 114 151 180 227
39 77 118 155 193 232
40 79 119 159 198 239
41 81 122 162 203 243
41 a3 124 185 207 248
42 84 127 189 211 253
43 a8 129 172 215 258
44 88 132 175 219 283
46 89 134 170 223 286
pH-6.5
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
20 39 59 78 98 117
20 40 80 80 100 120
20 41 61 a1 102 122
21 42 83 83 104 125
21 42 64 a5 106 127
22 43 85 87 108 130
22 44 86 88 110 132
23 45 88 8O 113 135
23 48 «S 92 115 138
23 47 70 93 117 140
24 48 72 95 110 143
24 49 73 07 122 148
25 49 74 so 123 148
26 50 78 101 128 151
pH-8.5
Log fciastivatlon
0.5 1.0 1.5 2.0 2.5 3.0
39 70 118 157 107 238
41 a1 122 163 203 244
42 64 128 186 210 252
43 87 130 173 217 260
45 89 134 178 223 267
48 91 137 183 229 274
47 04 141 167 234 261
48 98 144 191 230 287
40 09 147 198 245 294
50 100 150 200 250 300
61 102 153 204 255 308
52 104 158 208 280 312
53 108 159 212 285 318
54 108 182 218 270 324
pH = 7.0
Log tnactfvatlon
0.5 1.0 1.5 2.0 2.S 3.0
23 46 70 03 118 139
24 48 72 95 119 143
24 40 73 97 122 146
25 50 75 99 124 149
25 51 78 101 127 152
26 52 7S 103 129 155
26 53 79 105 132 158
27 54 81 108 136 Ia2
29 95 a3 110 138 165
28 56 65 113 141 189
29 57 86 115 143 172
.29 59 89 117 148 175
30 59 88 119 148 178
30 81 81 121 152 182
pH< -9.0
Log Inactivotlon
0.5 1.0 1.5 2.0 2.5 3.0
47 03 140 188 233 270
49 97 148 194 243 291
50 loo 151 201 251 301
52 104 158 208 280 312
S3 107 180 213 287 320
55 110 185 219 274 320
56 112 180 225 281 337
58 115 173 230 299 345
59 118 177 235 204 353
80 120 181 241 301 381
81 123 184 245 307 388
83 125 188 250 313 375
84 127 191 255 318 382
85 130 105 259 324 389
pH-7,8
Log InaetlvstJon
0.5 1.0 1.5 2.0 2.5 3.0
28 55 a3 111 138 166
29 57 88 114 143 171
29 58 88 117 146 175
30 iO 00 119 140 179
31 81 02 122 153 183
31 82 94 125 158 197
32 64 98 129 160 192
33 65 98 131 183 198
33 87 100 133 187 200
34 86 102 138 170 204
35 70 105 130 174 209
38 71 107 142 178 213
36 72 109 145 181 217
37 74 111 147 184 221
NOTE: GT 08.0 » CT for 3-)og Inactivation.
-------
'able D-3. CT Values for Inactivation of Giardia Cysts by Free Chlorine at 10 "C
Marina
onoantration
(mg/U
c - o . 4
0.8
0.9
1
1.2
1.4
1.8
1.6
2
2.2
2.4
2.6
2.8
3
Torino
aficentration
(mq/L)
C-O.4
0.8
0.8
1
1.2
1.4
1.8
1.8
2
2.2
2.4
2.8
2.8
3
pH< -6.0
Log Inactfvation
n 5 1 15 9 95 3D
12 '24 37 49 81 73
13 25 38 SO 63 79
13 28 39 52 85 78
13 28 40 53 68 79
13 27 40 53 87 SO
14 27 41 55 88 62
14 26 42 55 69 63
14 29 43 57 72 88
15 20 44 58 73 87
15 30 45 59 74 89
15 30 45 60 75 so
15 31 46 81 77 92
18 31 47 62 78 03
16 32 49 63 70 05
pH - a.O
Log Inactivation
0.5 1 1.5 2.0 2.5 3.0
25 50 75 00 124 149
28 51 77 102 128 153
28 53 79 105 132 158
27 54 61 108 135 182
28 55 63 111 136 188
28 67 85 113 142 170
20 58 a? 118 145 174
30 80 00 110 149 179
30 81 01 121 152 182
31 32 93 124 155 188
32 83 85 127 159 100
32 85 97 129 182 104
33 66 99 131 184 107
34 87 101 134 188 201
pH-e.5
Log Inactivation
0.5 1 1.5 2 2.5 3.0
15 20 44 50 73 88
15 30 45 80 76 90
15 31 48 81 77 02
16 31 47 83 78 04
18 32 48 83 79 95
18 33 49 85 a2 88
17 33 50 66 93 99
17 34 51 67 a4 101
17 35 52 69 a7 Io4
18 35 53 70 88 106
18 36 54 71 88 107
10 37 55 73 02 110
10 37 56 74 93 111
19 38 57 75 04 113
pH - 0,5
Log Inaethratfon
0.5 1.0 1.5 2.0 2.5 3.0
30 SB B9 119 148 177
31 61 92 122 153 183
32 63 95 126 1SB 180
33 85 98 130 183 195
33 87 loo 133 187 200
34 89 103 137 172 208
35 70 106 141 178 211
36 72 108 143 179 215
37 74 111 147 184 221
38 75 113 150 188 225
38 77 115 153 192 230
39 78 117 158 195 234
40 SO 120 159 189 230
41 81 122 182 203 243
pH-7.0
Log Inactivation
0.6 I 1.5 2 2.5 3.0
17 35 52 89 87 104
18 36 54 71 S3 107
18 37 55 73 02 110
10 37 58 75 93 112
19 38 57 76 95 114
19 39 58 77 07 118
20 40 80 79 93 119
20 41 61 a1 102 122
21 41 82 a3 103 124
21 42 84 85 Io6 127
22 43 65 a8 108 129
22 44 66 87 100 131
22 45 87 80 112 134
23 46 89 01 114 137
pH < -9.0
Log inactlvation
0.5 1.0 1.5 2.0 2.5 3.0
35 70 105 139 174 209
38 73 Ib8 145 182 218
38 75 113 151 188 228
39 78 117 156 195 234
40 80 120 180 200 240
41 a2 124 165 208 247
42 a4 127 188 211 243
43 96 130 173 218 250
44 8§ 133 177 221 285
45 00 136 161 228 271
46 92 138 184 230 278
47 94 141 187 234 281
48 98 144 191 230 287
40 97 148 196 243 202
pH-7.5
Log Inactivatlon
0.5 1 1.5 2 2.5 3.0
21 42 83 S3 Io4 '125
21 43 84 85 107 128
22 44 88 87 108 131
22 45 87 89 112 134
23 48 SO 01 114 137
23 47 70 03 117 140
24 46 72 98 120 144
26 40 74 98 123 147
25 50 75 100 125 180
28 61 77 102 128 153
28 52 79 105 131 157
27 53 80 107 133 160
27 54 a2 Io9 138 163
29 55 63 111 138 168
NOTE: CT 99.9 « CT for 3-teg inactivatlon.
-------
Table D-4. CT Values for Inactivation of Giardia Cysts by Free Chlorine at 15 °C
Norlm
oncant ration
(mg/U
< -O.I
0.6
0.6
I
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
Marine
loncentration
(mg/U
<-0.<
0.6
0. ff
1
1.2
1.4
1.6
1.6
2
2.2
2.4
2.6
2.6
3
pH<-6.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
16 25 33 41 49
8 17 25 33 42 50
9 17 26 35 43 52
9 18 27 35 44 53
9 18 27 36 45 54
9 18 26 37 46 55
9 19 26 37 47 58
10 19 29 36 48 57
10 1s 2s 39 49 58
10 20 30 39 49 59
10 20 30 40 50 60
10 20 31 41 51 61
10 21 31 41 52 62
11 21 32 42 53 63
pH-8.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
17 33 50 66 83 99
17 34 51 68 85 102
16 35 53 70 66 105
18 36 54 72 90 108
19 37 56 74 93 111
19 38 57 76 95 114
19 39 58 77 97 116
20 40 60 79 99 119
20 41 61 81 102 122
21 41 62 63 103 124
21 42 64 85 106 127
22 43 65 86 108 129
22 44 66 88 110 132
22 45 67 89 112 134
pH-8.5
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
] 20 30 39 49 59
1 20 30 40 50 60
1 20 31 41 51 61
11 21 32 42 53 63
11 21 32 43 53 64
11 22 33 43 54 65
11 22 33 44 55 66
11 23 34 45 57 68
12 23 35 46 58 69
12 23 35 47 58 70
12 24 36 46 60 72
12 24 37 49 61 73
12 25 37 49 62 74
13 25 38 51 63 76
pH-8.5
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
20 39 59 79 96 116
20 41 61 61 102 122
21 42 63 64 105 126
22 43 65 67 109 130
22 45 67 69 II2 134
23 46 69 91 114 137
24 47 71 94 118 141
24 46 72 96 120 144
25 49 74 96 123 147
25 50 75 100 125 150
26 51 77 102 126 153
26 52 78 104 130 156
27 53 60 106 133 159
27 54 81 106 135 162
pH-7.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
12 23 35 47 58 70
12 24 36 48 60 72
12 24 37 49 61 73
13 25 38 50 83 75
13 25 38 51 63 76
13 26 39 52 65 78
13 26 40 53 66 79
14 27 41 54 68 61
14 26 42 55 69 63
14 28 43 57 71 95
14 29 43 57 72 86
15 29 44 59 73 88
15 30 45 59 74 89
15 30 46 61 76 81
pH< -0.0
Log Inactivatlon
0.5 1.0 1.5 2.0 2.5 3.0
23 47 70 93 117 140
24 49 73 97 122 146
25 50 76 101 126 151
26 52 78 104 130 156
27 53 80 107 133 160
28 55 83 110 139 165
28 56 65 113 141 169
29 56 67 115 144 173
30 58 80 118 146 177
30 60 91 121 151 181
31 61 92 123 153 194
31 63 94 125 157 166
32 64 96 127 158 191
33 65 98 130 163 195
pH-7.5
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
14 29 42 55 69 83
14 2s 43 57 72 86
15 29 44 59 73 88
15 30 45 60 75 9O
15 31 46 81 77 92
18 31 47 63 78 04
16 32 46 64 80 98
18 33 49 65 82 98
17 33 50 67 63 1OO
17 34 51 68 85 102
18 35 53 70 88 105
18 36 54 71 89 107
19 36 55 73 91 1O9
19 37 56 74 93 111
NOTE: CT 99.9 - CT for 3-log inactivation.
-------
Fable D-5. CT Values for Inactivation of Giardia Cysts by Free Chlorine at 20 °C
Marine
oneentration
<-0.4
0.6
0,8
t
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.9
3
Narine
oncsntration
Imq/L)
<=0,4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
pH<-fl.O
Log Inactivation
n R in 15 ^ o, 25 30
S 12 18 24 30 38
6 13 18 25 32 38
7 13 20 28 33 38
7 13 20 26 33 39
7 13 20 27 33 40
7 14 21 27 34 41
7 14 21 28 35 42
7 14 22 28 36 43
1 15 22 28 37 44
7 15 22 29 37 44
8 15 23 30 38 45
8 15 23 31 38 48
8 16 24 31 39 47
8 16 24 31 3i 47
pH-S.O
Lot Inactivation
05 1 1.5 20 2.5 3.0
12 25 37 49 62 74
13 26 39 51 84 77
13 26 40 83 88 78
14 27 41 54 68 81
14 26 42 55 68 S3
14 26 43 57 71 65
15 23 44 56 73 87
15 30 45 59 74 89
15 30 46 61 76 91
18 31 47 62 78 93
16 32 48 83 79 96
16 32 49 85 81 87
17 33 SO «B 83 88
17 34 51 87 84 101
pH-6.5
Log Inactivation
05 1.0 15 2.0 2.6 3.0
7 15 22 28 37 44
8 15 23 30 38 45
8 15 23 31 36 46
8 18 24 31 38 47
8 16 24 32 40 48
8 16 25 33 41 49
8 17 25 33 42 50
8 17 26 34 43 51
9 17 26 35 43 52
a 18 27 35 44 53
8 18 27 36 45 84
9 18 28 37 48 55
9 19 28 37 47 58
10 19 29 38 48 57
pH-B.i
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
15 30 45 59 74 69
15 31 46 61 77 92
16 32 48 63 79 95
16 33 49 66 62 98
17 33 50 87 33 100
17 34 52 69 86 103
18 35 53 70 66 106
18 36 54 72 90 108
18 37 65 73 92 110
19 36 57 75 94 113
18 38 58 77 98 115
20 38 59 78 98 117
20 40 80 79 89 119
20 41 61 81 102 122
pH-7.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
9 17 26 35 43 52
3 16 27 38 45 54
8 18 26 37 48 55
9 13 28 37 47 68
10 19 29 38 48 57
10 19 29 39 48 58
10 20 30 39 49 59
10 20 31 41 61 61
10 21 31 41 52 62
11 21 32 42 63 63
11 22 33 43 54 65
1"! 22 33 44 65 66
11 22 34 45 56 87
11 23 34 45 57 68
0H<-8.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
18 35 53 70 88 105
18 3* 55 73 91 109
13 38 57 75 94 113
20 39 59 78 98 117
20 40 60 80 100 120
21 41 62 82 103 123
21 42 83 64 105 126
22 43 85 S6 108 120
22 44 86 88 110 132
23 45 68 80 113 135
23 48 69 92 115 138
24 47 71 94 118 141
24 48 72 95 119 143
24 49 73 97 122 146
pH~7.S
Log Inactfvation
0.5 1.0 1.5 2.0 2.5 3.0
10 21 31 41 52 82
11 21 32 43 S3 64
11 22 33 44 55 66
11 22 34 45 58 67
12 23 35 46 58 69
12 23 35 47 56 70
12 24 36 48 80 72
12 25 37 49 62 74
13 25 38 50 83 75
13 26 39 51 84 77
13 26 39 52 86 78
13 27 40 53 67 BO
14 27 41 54 88 81
14 28 42 55 89 83
NOTE: CT 88,8 = CT for 3-log Inaotivatlon.
-------
Table D-6. CT Values for Inactivation of Giardia Cysts by Free Chlorine at 25 °C
riorirw
mcentration
(mg/L)
<=0.4
0.6
0.9
1
1.2
1.4
1.6
1.9
2
2.2
2.4
2.6
2.8
3
farina
Hicamration
(mg/L)
< -0.4
0.6
0.8
1
1.2
1.4
1.6
1.6
2
2.2
2.4
2.8
2.8
3
pH< -6.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
4 8 12 16 20 24
4 8 13 17 21 25
4 9 13 17 22 28
4 9 13 17 22 26
5 9 14 16 23 27
5 9 14 18 23 27
5 9 14 19 23 29
5 10 15 19 24 29
5 10 15 19 24 29
5 10 15 20 25 30
5 10 15 20 25 30
5 10 16 21 26 31
5 10 16 21 26 31
5 11 18 21 27 32
pH-8.0
Log Inactivalfon
0.5 1.0 1.5 2.0 2.5 3.0
8 17 25 33 42 50
9 17 26 34 43 51
9 18 27 35 44 53
9 18 27 36 45 54
9 18 28 37 46 55
10 19 29 38 48 57
10 19 29 39 48 56
10 20 30 40 50 80
10 20 31 41 51 61
10 21 31 41 52 62
11 21 32 42 53 63
11 22 33 43 54 65
11 22 33 44 55 66
11 22 34 45 56 67
pH-6.5
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
5 10 15 18 24 29
5 10 15 20 25 30
5 10 18 21 26 31
5 10 16 21 26 31
5 11 16 21 27 32
6 11 17 22 28 33
6 11 17 22 28 33
6 11 17 23 26 34
6 12 18 23 29 35
6 12 18 23 29 35
6 12 16 24 30 36
6 12 19 25 31 37
6 12 19 25 31 37
6 13 19 25 32 39
pH-8.5
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
10 20 30 39 49 59
11 20 31 41 51 61
11 21 32 42 53 63
11 22 33 43 54 65
11 22 34 45 56 67
12 23 35 46 56 69
12 23 35 47 56 70
12 24 36 48 60 72
12 25 37 49 62 74
13 25 36 50 63 75
13 26 39 51 84 77
13 28 39 52 65 78
13 27 40 53 67 80
14 27 41 54 66 El
pH-7.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
6 12 19 23 29 35
8 12 16 24 30 36
6 12 19 25 31 37
6 12 19 25 31 37
6 13 19 25 32 38
7 13 20 28 33 39
7 13 20 27 33 40
7 14 21 27 34 41
7 14 21 27 34 41
7 14 21 26 35 42
7 14 22 29 36 43
7 15 22 29 37 44
6 15 23 30 39 45
6 15 23 31 36 46
pH<-9.0
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
12 23 35 47 58 70
12 24 37 49 61 73
13 25 38 50 63 75
13 26 39 52 65 76
13 27 40 53 67 80
14 27 41 55 68 82
14 26 42 56 70 04
14 29 43 57 72 86
15 29 44 59 73 88
15 30 45 60 75 90
15 31 46 61 77 92
16 31 47 63 76 94
16 32 40 64 80 96
16 32 49 65 81 97
PH-7.5
Log Inactivation
0.5 1.0 1.5 2.0 2.5 3.0
7 14 21 26 35 42
7 14 22 2s 36 43
7 15 22 29 37 44
6 15 23 30 36 45
8 . 15 23 31 38 46
6 16 24 31 39 47
8 16 24 32 40 48
8 16 25 33 41 49
6 17 25 33 42 50
9 17 26 34 43 51
9 17 26 35 43 52
9 18 27 35 44 53
9 16 27 36 45 54
9 19 26 37 46 55
NOTE: CT 99.9 - CT for 3-log inactivatkm.
-------
Table D-7. CT Values for Inactivation of Viruses by Free Chlorine
Log Inactivation
2.0 3.0 4.0
PH
Temperature (C)
0.5
5
10
15
20
25
6-9 10
6 45
4 30
3 22
2 15
1 11
1 7
6-9 10
9 66
6 44
4 33
3 22
2 16
1 11
6-9 10
12 90
8 60
6 45
4 30
3 22
2 15
Table D-8. CT Values for Inactivation of Giardia Cysts by Chlorine Dioxide
Temperature (C)
0.5-log
1-log
1.5-log
2-log
2.5-log
3-log
< = 1
10
21
32
42
52
63
5
4.3
8.7
13
17
22
26
10
4
7.7
12
15
19
23
15
3.2
6.3
10
13
16
19
20
2.5
5
7.5
10
13
15
25
2
3.7
5.5
7.3
9
11
Table D-9. CT Values for Inactivation of Viruses by Chlorine Dioxide pH 6-9
Temperature (C)
2-log
3-log
4-log
< = 1 5
8.4 5.6
25.6 17.1
50.1 33.4
10
4.2
12.8
25.1
15
2.8
8.6
16.7
20
2.1
6.4
12.5
25
1.4
4.3
8.4
Table D-10. C . Values for Inactivation of Giardia Cysts by Ozone
Temperature (C)
0.5-tog
1-log
1.5-log
2-log
2.5-log
3-log
< = 1
0.48
0.97
1.5
1.9
2.4
2.9
5
0.32
0.63
0.95
1.3
1.6
1.9
10
0.23
0.48
0.72
0.95
1.2
1.43
15
0.16
0.32
0.48
0.63
0.79
0.95
20
0.1
0.2
0.36
0.48
0.6
0.72
25
0.08
0.16
0.24
0.32
0.4
0.48
742
-------
Table D-l 1. CT Values for Inactivation of Viruses by Ozone
Temperature (C)
2-log
3-log
4-log
< =1
0.9
1.4
1.8
5
0.6
0.9
1.2
10
0.5
0.8
1
15
0.3
0.5
0.6
20
0.25
0.4
0.5
25
0.15
0.25
0.3
Table D-12. CT Values for Inactivation of Giardia Cysts by Chloramine pH 6-9
Temperature (C)
0.5-log
l-log
1.5-log
2-log
2.5-log
3-log
< = 1
635
1270
1900
2535
3170
3800
5
365
735
1100
1470
1830
2200
10
310
615
930
1230
1540
1850
15
250
500
750
1000
1250
1500
20
185
370
550
735
915
1100
25
125
250
375
500
625
750
Table D-13. CT Values for Inactivation of Viruses by Chloramine
Temperature (C)
2-log
3-log
4-log
<=1
1243
2063
2883
5
857
1423
1988
10
643
1067
1491
15
428
712
994
20
321
534
746
25
214
356
497
Table D-14. CT Values for Inactivation of Viruses by UV
Log Inactivation
2 3
21
36
143
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Appendix E
Performance Limiting Factors Summary Materials
and Definitions
145
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CPE Factor Summary Sheet Terms
Plant Type
Source Water
Performance Summary
Ranking Table
Rank
Rating
Brief but specific description of plant type (e.g., conventional
with flash mix, flocculation, sedimentation, filtration and chlorine
disinfection; or direct filtration with flash mix, flocculation and
chlorine disinfection).
Brief description of source water (e.g., surface water including
name of water body).
Brief description of plant performance based on performance
assessment component of the CPE (i.e., ability of plant to meet
optimized performance goals).
A listing of identified performance limiting factors that directly
impact plant performance and reliability.
Relative ranking of factor based on prioritization of all "A" and
"B" rated factors identified during the CPE.
Rating of factor based on impact on plant performance and
reliability:
A — Major effect on a long-term repetitive basis
B — Moderate effect on a routine basis or major effect on a
periodic basis
C — Minor effect
Performance Limiting
Factor (Category)
Notes
Factor identified from Checklist of Performance Limiting Factors,
including factor category (e.g., administration, design, operation,
and maintenance).
Brief listing of reasons each factor was identified (e.g., lack of
process control testing, no defined performance goals).
146
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CPE Performance Limiting Factors Summary
Plant Name/Location:
CPE Performed By:
CPE Date:
Plant Type:
Source Water:
Performance Summary:
Ranking Table
Rank
Rating
Performance Limiting Factor (Category)
Rating Description
A — Major effect on long-term repetitive basis.
B — Moderate effect on a routine basis or major effect on a periodic basis.
C — Minor effect.
147
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Performance Limiting Factors Notes
Factor
Notes
148
-------
Checklist of Performance Limiting Factors
A. ADMINISTRATION
1. Plant Administrators
a. D Policies
b. D Familiarity With Plant Needs
c. Q Supervision
d. D Planning
e. D Complacency
f. D Reliability
g. D Source Water Protection
2. Plant Staff
a. D Number
b. D Plant Coveraae
c. D Personnel Turnover
d. Q Compensation
e. Cl Work Environment
f. D Certification
3. Financial
a. D Ooeratina Ratio
b. D Coveraae Ratio
c. 0 Reserves
B. DESIGN
1. Source Water Quality
a. D Microbial Contamination
2. Unit Process Adequacy
a. D Intake Structure
b. D Presedimentation Basin
c. D Raw Water Pumoina
d. D Flow Measurement
e. D Chemical Storaae and Feed
Facilities
f. D Flash Mix
g. Q Flocculation
h. U Sedimentation
i. D Filtration
j. D Disinfection
k. D Sludge/Backwash Water
Treatment and Disposal
149
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3. Plant Operabilitv
a. Q 'Process Flexibility
b. Q Process Controllability
c. U Process Instrumentation/
Automation
d. Q Standby Units for Kev
Eauipment
e. Q Flow Proportioning
f. U Alarm Systems
g. U Alternate Power Source
h. Q Laboratory Space and Eauipment
i. D Sample Taos
C. OPERATION
1. Testing
a. Cl Process Control Testing
b. Q Representative Sampling
2. Process Control
a. D Time on the Job
b. D Water Treatment Understanding
c. D Application of Concepts and
Testina to Process Control
3. Operational Resources
a. D Trainina Proaram
b. D Technical Guidance
c. D Operational Guidelines/Procedures
D. MAINTENANCE
1. Maintenance Program
a. El Preventive
b. D Corrective
c. D Housekeeping
2. Maintenance Resources
a. •! Materials and Eguioment
b. Cl Skills or Contract Services
150
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Definitions for Assessing Performance Limiting Factors
NOTE: The following list of defined factors is provided to assist the evaluator with identifying perform-
ance limitations associated with protection against microbial contaminants in water treatment systems.
Performance limiting factors are described below using the following format.
A. CATEGORY
1. Subcategory
a. Factor Name
• Factor description
9 Examole of factor aoolied to soecific plant or utility
A. Administration
1. Plant Administrators
a. Policies
• Do existing policies or the lack of policies discourage staff members from making
required operation, maintenance, and management decisions to support plant perform-
ance and reliability?
9 Utility administration has not communicated a clear policy to optimize plant per-
formance for public health protection.
9 Multiple management levels within a utility contribute to unclear communication
and lack of responsibility for plant operation and performance.
9 Cost savings is emphasized by management at the expense of plant performance.
9 Utility managers do not support reasonable training and certification requests by
plant staff.
9 Administration continues to allow connections to the distribution system without
consideration for the capacity of the plant.
b. Familiarity With Plant Needs
• Do administrators lack first-hand knowledge of plant needs?
9 The utility administrators do not make plant visits or otherwise communicate with
plant staff.
9 Utility administrators do not request input from plant staff during budget develop-
ment.
c. Supervision
• Do management styles, organizational capabilities, budgeting skills, or communication
practices at any management level adversely impact the plant to the extent that per-
formance is affected?
9 A controlling supervision style does not allow the plant staff to contribute to opera-
tional decisions.
9 A plant supervisor's inability to set priorities for staff results in insufficient time
allocated for process control.
d. Planning
• Does the lack of long range planning for facility replacement or alternative source water
quantity or quality adversely impact performance?
9 A utility has approved the connection of new customers to the water system with-
out considering the water demand impacts on plant capacity.
9 An inadequate capital replacement program results in utilization of outdated equip-
ment that cannot support optimization goals.
151
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e. Complacency
• Does the presence of consistent, high quality source water result in complacency within
the water utility?
9 Due to the existence of consistent, high quality source water, plant staff are not
prepared to address unusual water quality conditions.
9 A utility does not have an emergency response plan in place to respond to unusual
water quality conditions or events.
f. Reliability
• Do inadequate facilities or equipment, or the depth of staff capability, present a poten-
tial weak link within the water utility to achieve and sustain optimized performance?
9 Outdated filter control valves result in turbidity spikes in the filtered water entering
the plant clearwell.
9 Plant staff capability to respond to unusual water quality conditions exists with
only the laboratory supervisor.
g. Source Water Protection
• Does the water utility lack an active source water protection program?
9 The absence of a source water protection program has resulted in the failure to
identify and eliminate the discharge of failed septic tanks into the utility's source
water lake.
9 Utility management has not evaluated the impact of potential contamination
sources on water quality within their existing watershed.
2. Plant Staff
a. Number
4 Does a limited number of people employed have a detrimental effect on plant operations
or maintenance?
9 Plant staff are responsible for operation and maintenance of the plant as well as
distribution system and meter reading, limiting the time available for process con-
trol testing and process adjustments.
b. Plant Coveraae
• Does the lack of plant coverage result in inadequate time to complete necessary opera-
tional activities? (Note: This factor could have significant impact if no alarm/shutdown
capability exists - see design factors).
9 Staff are not present at the plant during evenings, weekends, or holidays to make
appropriate plant and process control adjustments.
9 Staff are not available to respond to changing source water quality characteristics.
c. Personnel Turnover
• Does high personnel turnover cause operation and maintenance problems that affect
process performance or reliability?
9 The lack of support for plant needs results in high operator turnover and, subse-
quently, inconsistent operating procedures and low staff morale.
d. Compensation
• Does a low pay scale or benefit package discourage more highly qualified persons from
applying for operator positions or cause operators to leave after they are trained?
9 The current pay scale does not attract personnel with sufficient qualifications to
support plant process control and testing needs.
B. Work Environment
• Does a poor work environment create a condition for "sloppy work habits" and lower
operator morale?
9 A small, noisy work space is not conducive for the recording and development of
plant data.
152
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f. Certification
• Does the lack of certified personnel result in poor 0 & M decisions?
9 The lack of certification hinders the staff's ability to make proper process control
adjustments.
3. Financial
a. Ooeratina Ratio
• Does the utility have inadequate revenues to cover operation, maintenance, and
replacement of necessary equipment (i.e., operating ratio less than 1 .0)?
9 The current utility rate structure does not provide adequate funding and limits
expenditures necessary to pursue optimized performance (e.g., equipment
replacement, chemical purchases, spare parts).
b. Coveraae Ratio
• Does the utility have inadequate net operating profit to cover debt service requirements
(i.e., coverage ratio less than 1.25)?
9 The magnitude of a utility's debt service has severely impacted expenditures on
necessary plant equipment and supplies.
c. Reserves
• Does the utility have inadequate reserves to cover unexpected expenses or future
facility replacement?
9 A utility has a 40-year-old water treatment plant requiring significant modifications;
however, no reserve account has been established to fund these needed capital
expenditures.
B. Design
1. Source Water Quality
a. Microbial Contamination
• Does the presence of microbial contamination sources in close proximity to the water
treatment plant intake impact the plant's ability to provide an adequate treatment bar-
rier?
9 A water treatment plant intake is located downstream of a major wastewater
treatment plant discharge and is subject to a high percentage of this flow during
drought periods.
2. Unit Process Adequacy
a. Intake Structure
• Does the design of the intake structure result in excessive clogging of screens, build-up
of silt, or passage of material that affects plant equipment?
9 The location of an intake structure on the outside bank of the river causes exces-
sive collection of debris, resulting in plugging of the plant flow meter and static
mixer.
9 The design of a reservoir intake structure does not include flexibility to draw water
at varying levels to minimize algae concentration.
b. Presedimentation Basin
• Does the design of an existing presedimentation basin or the lack of a presedimentation
basin contribute to degraded plant performance?
9 The lack of flexibility with a presedimentation basin (i.e., number of basins, size,
bypass) causes excessive algae growth, impacting plant performance.
9 A conventional plant treating water directly from a "flashy" stream experiences
performance problems during high turbidity events.
153
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c. Raw Water Pumping
• Does the use of constant speed pumps cause undesirable hydraulic loading on down-
stream unit processes?
9 The on-off cycle associated with raw water pump operation at a plant results in
turbidity spikes in the sedimentation basin and filters.
d. Flow Measurement
• Does the lack of flow measurement devices or their accuracy limit plant control or
impact process control adjustments?
9 The flow measurement device in a plant is not accurate, resulting in inconsistent
flow measurement records and the inability to pace chemical feed rates according
to flow.
e. Chemical Storage and Feed Facilities
• Do inadequate chemical storage and feed facilities limit process needs in a plant?
9 Inadequate chemical storage facilities exist at a plant, resulting in excessive chemi-
cal handling and deliveries.
9 Capability does not exist to measure and adjust the coagulant and flocculant feed
rates.
f. Flash Mix
• Does inadequate mixing result in excessive chemical use or insufficient coagulation to
the extent that it impacts plant performance?
9 A static mixer does not provide effective chemical mixing throughout the entire
operating flow range of the plant.
9 Absence of a flash mixer results in less than optimal chemical addition and insuffi-
cient coagulation.
g. Flocculation
• Does a lack of flocculation time, inadequate equipment, or lack of multiple flocculation
stages result in poor floe formation and degrade plant performance?
9 A direct filtration plant, treating cold water and utilizing a flocculation basin with
short detention time and hydraulic mixing, does not create adequate floe for filtra-
tion.
h. Sedimentation
• Does the sedimentation basin configuration or equipment cause inadequate solids
removal that negatively impacts filter performance?
9 The inlet and outlet configurations of the sedimentation basins cause short-
circuiting, resulting in poor settling and floe carryover to the filters.
9 The outlet configuration causes floe break-up, resulting in poor filter performance
9 The surface area of the available sedimentation basins is inadequate, resulting in
solids loss and inability to meet optimized performance criteria for the process.
\. Filtration
• Do filter or filter media characteristics limit the filtration process performance?
9 The filter loading rate in a plant is excessive, resulting in poor filter performance.
9 Either the filter underdrain or support gravel have been damaged to the extent that
filter performance is impacted.
• Do filter rate-of-flow control valves provide a consistent, controlled filtration rate?
9 The rate-of-flow control valves produce erratic, inconsistent flow rates that result
in turbidity and/or particle spikes.
• Do inadequate surface wash or backwash facilities limit the ability to clean the filter
beds?
9 The backwash pumps for a filtration system do not have sufficient capacity to
adequately clean the filters during backwash.
154
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9 The surface wash units are inadequate to properly clean the filter media.
9 Backwash rate is not sufficient to provide proper bed expansion to properly clean
the filters.
j. Disinfection
• Do the disinfection facilities have limitations, such as inadequate detention time,
improper mixing, feed rates, proportional feeds, or baffling, that contribute to poor dis-
infection?
9 An unbaffled clean/veil does not provide the necessary detention time to meet the
Giardia inactivation requirements of the SWTR.
k. Sludge/Backwash Water Treatment and Disposal
• Do inadequate sludge or backwash water treatment facilities negatively influence plant
performance?
9 The plant is recycling backwash decant water without adequate treatment.
9 The plant is recycling backwash water intermittently with high volume pumps.
9 The effluent discharged from a sludge/backwash water storage lagoon does not
meet applicable receiving stream permits.
9 Inadequate long-term sludge disposal exists at a plant, resulting in reduced cleaning
of settling basins and recycle of solids back to the plant.
3. Plant Operability
a. Process Flexibility
• Does the lack of flexibility to feed chemicals at desired process locations or the lack of
flexibility to operate equipment or processes in an optimized mode limit the plant's
ability to achieve desired performance goals?
9 A plant does not have the flexibility to feed either a flocculant aid to enhance floe
development and strength or a filter aid to improve filter performance.
9 A plant includes two sedimentation basins that can only be operated in series.
b. Process Controllability
• Do existing process controls or lack of specific controls limit the adjustment and control
of a process over the desired operating range?
9 Filter backwash control does not allow for the ramping up and down of the flow
rate during a backwash event.
9 During a filter backwash, the lack of flow control through the plant causes hydrau-
lic surging through the operating filters.
9 The level control system located in a filter influent channel causes the filter effluent
control valves to overcompensate during flow rate changes in a plant.
9 Flows between parallel treatment units are not equal and cannot be controlled.
9 The plant influent pumps cannot be easily controlled or adjusted, necessitating
automatic start-up/shutdown of raw water pumps.
9 Plant flow rate measurement is not adequate to allow accurate control of chemical
feed rates.
9 Chemical feed rates are not easily changed or are not automatically changed to
account for changes in plant flow rate.
c. Process Instrumentation/Automation
• Does the lack of process instrumentation or automation cause excessive operator time
for process control and monitoring?
9 A plant does not have continuous recording turbidimeters on each filter, resulting
in extensive operator time for sampling.
155
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9 The indication of plant flow rate is only located in the pipe gallery, which causes
difficulty in coordinating plant operation and control.
9 Automatic shutdown/start-up of the plant results in poor unit process performance.
d. Standby Units for Kev Equipment
• Does the lack of standby units for key equipment cause degraded process performance
during breakdown or during necessary preventive maintenance activities?
9 Only one backwash pump is available to pump water to a backwash supply tank,
and the combination of limited supply tank volume and an unreliable pump has
caused staff to limit backwashing of filters during peak production periods.
e. Flow Proportioning
• Does inadequate flow splitting to parallel process units cause individual unit overloads
that degrade process performance?
9 In fluent flow to a plant is hydraulically split to multiple treatment trains, and
uneven flow distribution causes overloading of one fiocculation/sedimentation train
over the others.
f. Alarm Systems
• Does the absence or inadequacy of an alarm system for critical equipment or processes
cause degraded process performance?
9 A plant that is not staffed full-time does not have alarm and plant shut-down capa-
bility for critical finished water quality parameters (i. e., turbidity, chlorine residual).
g. Alternate Power Source
• Does the absence of an alternate power source cause reliability problems leading to
degraded plant performance?
9 A plant has frequent power outages, and resulting plant shutdowns and start-ups
cause turbidity spikes in the filtered water.
h. Laboratory Space and Equipment
• Does the absence of an adequately equipped laboratory limit plant performance?
9 A plant does not have an adequate process control laboratory for operators to per-
form key tests (i.e., turbidity, jar testing).
i. Sample Taos
* Does the lack of sample taps on process flow streams prevent needed information from
being obtained to optimize performance?
9 Filter-to-waste piping following plant filters does not include sample taps to meas-
ure the turbidity spike folio wing back wash.
9 Sludge sample taps are not available on sedimentation basins to allow process con-
trol of the sludge draw-off from these units.
Operation
1. Testing
a. Process Control Testing
• Does the absence or wrong type of process control testing cause improper operational
control decisions to be made?
9 Plant staff do not measure and record raw water pH, alkalinity, and turbidity on a
routine basis: consequently, the impact of raw water quality on plant performance
cannot be assessed.
9 Sedimentation basin effluent turbidity is not measured routinely in a plant.
156
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b. Representative Sampling
• Do monitoring results inaccurately represent plant performance or are samples collected
improperly?
9 Plant staff do not record the maximum turbidity spikes that occur during filter
operation and following filter back wash events.
9 Turbidity sampling is not performed during periods when the reclaim backwash
water pump is in operation.
2. Process Control
a. Time on the Job
• Does staff's short time on the job and associated unfamiliarity with process control and
plant needs result in inadequate or improper control adjustments?
9 Utility staff, unfamiliar with surface water treatment, were given responsibility to
start a new plant; and lack of experience and training contributed to improper
coagulation control and poor performance.
b. Water Treatment Understanding
• Does the operator's lack of basic water; treatment understanding contribute to improper
operational decisions and poor plant performance or reliability?
9 Plant staff do not have sufficient understanding of water treatment processes to
make proper equipment or process adjustments.
9 Plant staff have limited exposure to water treatment terminology, limiting their
ability to interpret information presented in training events or in published informa-
tion.
C. Application of Concepts and Testina to Process Control
• Is the staff deficient in the application of their knowledge of water treatment and inter-
pretation of process control testing such that improper process control adjustments are
made?
> Plant staff do not perform jar testing to determine appropriate coagulant dosages
for different water quality conditions.
> Plant filters are placed back in service following backwash without consideration
for effluent turbidity levels.
> Filter to waste valves are available but are not used following filter backwash.
> Plant staff do not calculate chemical dosages on a routine basis.
> Plant staff do not change chemical feed systems to respond to changes in raw
water quality.
> Filters are backwashed based on time in service or headloss rather than on opti-
mized performance goal for turbidity or particle removal.
> Plant staff "bump " filters by increasing the hydraulic loading to see if backwashing
is necessary.
> Sedimentation basin performance is controlled by visual observation rather than
process control testing.
3. Operational Resources
a. Trainina Program
• Does inadequate training result in improper process control decisions by plant staff?
9 A training program does not exist for new operators at a plant, resulting in incon-
sistent operator capabilities.
157
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b. Technical Guidance
• Does inappropriate information received from a technical resource (e.g., design engi-
neer, equipment representative, regulator, peer) cause improper decisions or priorities to
be implemented?
9 A technical resource occasionally provides recommendations to the plant staff:
however, recommendations are not based on plant-specific studies.
c. Operational Guidelines/Procedures
• Does the lack of plant-specific operating guidelines and procedures result in inconsistent
operational decisions that impact performance?
9 The lack of operational procedures has caused inconsistent sampling between
operator shifts and has led to improper data interpretation and process control
adjustments.
D. Maintenance
1. Maintenance Program
a. Preventive
• Does the absence or lack of an effective preventive maintenance program cause unnec-
essary equipment failures or excessive downtime that results in plant performance or
reliability problems?
9 Preventive maintenance is not performed on plant equipment as recommended by
the manufacturer, resulting in premature equipment failures and degraded plant
performance.
9 A work order system does not exist to identify and correct equipment that is func-
tioning improperly.
b. Corrective
• Does the lack of corrective maintenance procedures affect the completion of emergency
equipment maintenance?
9 A priority system does not exist on completion of corrective maintenance activities,
resulting in a critical sedimentation basin being out of service for an extended
period.
9 Inadequate critical spare parts are available at the plant, resulting in equipment
down time.
c. Housekeeping
• Does a lack of good housekeeping procedures detract from the professional image of
the water treatment plant?
9 An unkempt, cluttered working environment in a plant does not support the overall
good performance of the facility.
2. Maintenance Resources
a. Materials and Equipment
• Does the lack of necessary materials and tools delay the response time to correct plant
equipment problems?
9 Inadequate tool resources at a plant results in increased delays in repairing equip-
ment.
b. Skills or Contract Services
• Do plant maintenance staff have inadequate skills to correct equipment problems or do
the maintenance staff have limited access to contract maintenance services?
9 Plant maintenance staff do not have instrumentation and control skills or access to
contract services for these skills, resulting in the inability to correct malfunctioning
filter rate control valves.
158
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Appendix F
Data Collection Forms
159
-------
Contents
Section Page
Kick-Off Meeting 161 - 163
Administration Data 164 - 169
Design Data 170 - 180
Operations Data 181 - 189
Maintenance Data 190-191
Field Evaluation Data 192 - 197
Interview Data 198- 200
Exit Meeting 201 - 203
160
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KICK-OFF MEETING
A. Kick-Off Meeting Agenda
1.
Purpose of the CPE
• Background on CCP process development and application
• Basis for conducting the CPE at the utility
* Assess ability of plant to meet optimized performance goals
Optimized performance criteria description
Multiple barrier concept for microbial protection
* Identify factors limiting plant performance
• Describe follow-up activities
2. Schedule CPE events
• Plant tour
• On-site data collection
Performance
Design
Operations
Maintenance
Administration
Utility Staff Involved
Date/Time
Special studies
Interviews
Exit meeting
161
-------
KICK-OFF MEETING
3. Information Resources
• Performance monitoring records
• Plant operating records
• As-built construction drawings
• Plant flow schematic
• As-built construction drawings
• 0 & M manuals
• Equipment manuals
• Previous and current year budgets
• Organizational structure
• Water rate structure
162
-------
KICK-OFF MEETING
B. Attendance List
Utility Name
Date
Name
Title/Position
Teleohone No.
163
-------
ADMINISTRATION DATA
A. Name and Location
1. Name of Facility
2. Utility Name
3. Current Date
4. Contact Information:
Contact Name
Title
Mailing Address
Phone
Fax
Administration
Plant
B. Organization
1. Governing Body (name and scheduled meetings)
2. Utility structure (attach organizational chart if available)
764
-------
ADMINISTRATION DATA
3. Plant Organizational Structure (include operations, maintenance, laboratory personnel; attach chart if
available)
C. Communications
1. Utility Mission Statement
2. Water Quality Goals
765
-------
ADMINISTRATION DATA
3. Communication Mechanisms:
Type
Cl Staff Meetings
n Administrator/Board
Visits to Plant
d Reports (plant staff to
manager; manager to
governing board)
EH Public Relations/
Education
Description
D. Planning
1. Short-Term Needs
2. Long-Term Needs
766
-------
ADMINISTRATION DATA
E. Personnel
Title/Name
No.
Certification
Pay Scale
% Time
at Plant
Comments (e.g., vacant positions, adequacy of current staffing):
F. Plant Coverage
1. Shift Description (e.g., length, number per shift, weekend/holiday coverage)
2. Unstaffed Operation Safeguards (e.g., alarm/shutdown capability, dialer)
167
-------
ADMINISTRATION DATA
G. Financial Information
1. Budget (basis for budget: total utility D
plant only D)
Enter Year
1. Beginning Cash on Hand
2. Cash Receipts
a. Water Sales Revenue
b. Other Revenue (connection fees, interest)
c. Total Water Revenue (2a +2b)
d. Number of Customer Accounts
e. Average Charge per Account (2a •*• 26)
3. Total Cash Available (1 + 2c)
4. Operating Expenses
a. Total O&M Expenses*
b. Replacement Expenses
c. Total 0,M&R Expenses (4a + 4b)
d. Total Loan Payments (interest + principal)
e. Capital Purchases
f. Total Cash Paid Out (4c + 4d + 4e)
g. Ending Cash Position (3 - 4f)
5. Operating Ratio (2a + 4c>*
6. Coverage Ratio (2c - 4c) -*• (4d)t
Last Year Actual
7. Year End Reserves (debt, capital improvements)
8. End of Year Operating Cash (4g - 7)
Current Year Budget
Source: USEPA Region 8 Financial Analysis Document (1997)
* Includes employee compensation, chemicals, utilities, supplies, training, transportation,
insurance, etc.
± Measure of whether operating revenues are sufficient to cover O,M&R expenses. An
operating ratio of 1 .0 is considered minimum for a self-supporting utility.
t Measure of the sufficiency of net operating profit to cover debt service requirements of
the utility. Bonding requirements may require a minimum ratio (e.g., 1.25).
168
-------
ADMINISTRATION DATA
2. Supporting Financial Information:
Category
D
D
D
D
a
Rate Structure
. User fees
. Connection fees
• Planned rate changes
Debt Service
• Long-term debt
. Reserve account
Capital
Improvements
. Planning
. Reserve account
Budget Process
. Staff involvement
Spending Authorization
. Administrator
. Plant staff
Information
169
-------
DESIGN DATA
A. Plant Schematic and Capacity Information
1. Attach or draw plant flow schematic; include the following details:
• Source water type/location . Chemical injection locations
• Major unit processes • Piping flexibility
. Flow measurement locations . On-line monitoring type/location
2. Flow Conditions:
Parameter
Design Capacity
Average Annual Flow
Peak Instantaneous Flow
Flow
170
-------
DESIGN DATA
B. Major Unit Process Information
1. Flocculation:
Topic
1 . Description
2. Dimensions
3. Major Unit
Process
Evaluation
4. Other
Design
Information
(G values)
Description
Type (reel, turbine, hydraulic)
Number trains/stages per train
Control (constant/variable speed)
Information
Length per stage:
Width per stage:
Depth per stage:
Total volume:
Selected Process Parameter(s):
Detention time (min)
Assigned process capacity
Calculation of mixing energy as expressed by the mean velocity gradient (G) for mechanical mixing:
G = Velocity gradient, sec "'
U = viscosity, Ib-sec/ft2
v = volume, ft3
P = energy dissipated, ft-lblsec
= hp x 550 ft-lb/sec/hp
Calculation of G for hydraulic mixing:
G =
,1/2
p = water density, 62.4 Ib/ft3
hL = head loss, ft
t = detention time, sec
Viscosity -Of Water Versus Temperature
Temp. <°F)
32
40
BO
60
70
80
90
100
Temp. (°C)
0
4
10
16
21
27
32
38
Viscosity
x 10 "5
(Ib-sec/ft2)
3.746
3.229
2.735
2.359
2.050
1.799
1.595
1.424
171
-------
DESIGN DATA
B. Major Unit Process Information (cont.)
2. Sedimentation:
Topic
1 . Description
2. Dimensions |
3. Major Unit
Process
Evaluation
4. Other
Design
Information
Description
Type (conventional, tube settlers)
Number trains
Weir location
Sludge collection
information
Width:
Depth:
Total surface area:
Selected Process Parameter(s):
Surface loading rate
Assigned process capacity
172
-------
DESIGN DATA
B. Major Unit Process Information (cont.)
3. Filtration:
Topic
Description
Information
1. Description
Type (mono, dual, mixed)
Number of filters
Filter control (constant, declining)
Surface wash type (rotary, fixed)
2. Dimensions
Length or diameter:
Width:
Total surface area:
3. Media design conditions (depth, effective size, uniformity coefficient):
4. Backwash
Backwash initiation (headloss, turbidity, time):
Sequence (surface wash, air scour, flow ramping up/down, filter-to-waste):
173
-------
DESIGN DATA
B. Major Unit Process Information (cont.)
3. Filtration (cont.):
Topic
5. Major Unit
Process
Evaluation
6. Other
Design
Information
Description Information
Selected Process Parameter(s);
Surface loading rate
Assigned process capacity
174
-------
DESIGN DATA
B. Major Unit Process Information (cont.)
4. Disinfection:
Topic
1 . Description
2. Dimensions
3. Major Unit
Process
Evaluation
5. Other
Design
Information
Description
Contact type (clearwell, storage)
T10/T factor (see Table 4-4 or use
tracer study results)
Information
.ength or diameter:
Width:
Minimum operating depth:
Total volume:
Volume adjusted for T10/T:
Selected Process Parameters:
Disinfectant (chlorine, chloramines)
Max. disinfectant residual (mg/L)
Maximum pH
Minimum temperature (°C)
Required Giardia inactivation
Required virus inactivation
Assigned process capacity
175
-------
DESIGN DATA
C. Miscellaneous Equipment Information
1. Miscellaneous Equipment/Unit Processes:
Equipment/Process
1. Intake Structure
• Location
• Size of screen opening
• Design limitations
2. Presedimentation
. Detention time
. Flexibility to bypass
• Chemical feed capability
. Design limitations
3. Rapid Mix
. Type (mech., inline)
. Chemical feed options
. Mixing energy
. Design limitations
Description/Information
776
-------
DESIGN DATA
C. Miscellaneous Equipment Information (cont.)
1. Miscellaneous Equipment/Unit Processes (cont.):
Equipment/Process
4. Backwash/Sludge
Decant Treatment
•
•
. Design limitations
5. Sludge Handing
. Onsite storage volume
• Long-term disposal
. Design limitations
Description/Information
177
-------
DESIGN DATA
C. Miscellaneous Equipment Information (cont .)
4. Pumping:
Flow Stream Pumped
. Location
. Number of pumps
• Rated capacity
1.
2.
3.
4.
5.
6.
7.
Pump Type
. Turbine
. Centrifugal
Comments
• Flow control method
. Design issues
• Source of rated capacity (name plate,
specifications, flow meter)
180
-------
OPERATIONS DATA
A. Process Control Strategy and Communication
Describe the process control strategy used by the staff and associated communication mechanisms.
Topic
1. Process Control Strategy
• Does the staff set specific
performance targets? Are they
posted?
• Who sets process control
strategies and decisions?
» Are appropriate staff members
involved in process control
and optimization activities?
2. Communication Methods
• Does the staff have routine
plant/shift meetings?
• How is communication
conducted among operations,
maintenance, and lab?
• Does the staff develop and
follow operational procedures?
Description/Information
181
-------
OPERATIONS DATA
B. Process Control Procedures
Describe specific process control procedures for the following available processes.
Process
1. Intake Structure
• Flexibility to draw water from
different locations & depths
. Operational problems
2. Pumping/Flow Control
. Flow measurement and control
. Proportioning to multiple units
. Operational problems
3. Presedimentation
. Chemicals used/dose control
• Monitoring (turbidity)
• Sludge removal
• Operational problems
4. Preoxidation
. Chemicals used/dose control
• Monitoring (residual)
. Operational problems
Description/Information
182
-------
OPERATIONS DATA
Describe specific process control, procedures for the following available processes (cont.)
Process
5. Coagulation/Softening
• Chemicals used/feed location
. Dose control (adjustment for
flow changes; adjustment for
water quality - jar testing,
streaming current, pilot filter)
. Monitoring (turbidity, particle
counting)
• Operational problems
6. Flocculation
• Mixing energy adjustment
• Use of flocculant aid
. Monitoring
. Operational problems
7. Sedimentation
• Performance objective/
monitoring (turbidity)
• Sludge removal (control,
adjustment)
• Operational problems
Description/Information
183
-------
OPERATIONS DATA
Describe specific process control procedures for the following available processes (cont.)
Process
J. Filtration
1 Performance objective/
monitoring (turbidity, particles,
headloss, run time)
' Rate control due to demand,
filter backwash
> Use of filter aid polymer
• Basis for backwash initiation
(turbidity, particles, headloss,
time)
> Backwash procedures (wash
sequence, duration and rates,
basis for returning filter to
service)
• Filter/media inspections
(frequency and type)
» Operational problems
9. Disinfection
• Performance objective/
monitoring (residual, CT)
. CT factors (pH, minimum depth
of contactor, T10/T, maximum
residual)
. Operational problems
Description/Information
184
-------
OPERATIONS DATA
Describe specific process control procedures for the following available processes (cont.)
Process
10. Stabilization
• Chemical used/feed location
• Performance objective/
monitoring (pH, index)
. Operational problems
11. Decant Recycle
. Duration, % of plant flow
• Type of treatment (settling,
chemical addition)
• Operational problems
12. Sludge Treatment
Description/Information
185
-------
OPERATIONS DATA
C. Data Management
Describe data collection and management approaches and tools used by plant staff.
Topic
1. Data Collection
. Type of forms used (water
quality testing, shift rounds,
plant log)
. Computer (SCADA, database)
2. Data Application
. Development of daily, monthly
reports
. Development of trend charts
Description/Information
D. Problem Solving and Optimization Activities
Describe specific approaches and tools used to solve problems or optimize plant processes.
Topic
1 . Problem Solving/Optimization
• Use of special studies
• Pilot plant
. List recent and ongoing
problem solving/optimization
activities
. Available resources (technical
assistance providers, training,
manuals of practice)
Description/Information
186
-------
OPERATIONS DATA
E. Complacency and Reliability
Describe specific approaches used to address complacency and reliability issues in the plant.
Topic
Description/Information
1. Complacency
• How does staff respond to
unusual water quality
conditions?
• Does staff have an emergency
response plan? How does staff
train for unusual conditions or
events?
2. Reliability
• Does staff capability to make
process control decisions
exist at more than one level?
187
-------
OPERATIONS DATA
F. Laboratory Capability
1. Describe available analytical testing capability.
Analytical Capability
. Color
• Jar test
• Particle counting
• pH
• Solids (dissolved)
• Taste and odor
• Temperature
• Turbidity
• Aluminum
• Calcium
• Fluoride
• Hardness
• Iron
• Magnesium
• Manganese
• Sodium
• Alkalinity
• Ammonia Nitrogen
• Nitrite/nitrate
• Phosphate
• Sulfate
• Chlorine residual
• Bacteriological
• Disinfection byproducts
Capability S
Description/Comments
188
-------
OPERATIONS DATA
2. Describe laboratory space/equipment and procedures.
Process
Lab Space and Equipment
• Does adequate lab space exist?
. Do adequate equipment and
facilities exist?
Lab Procedures
• Is testing conducted following
standard procedures?
• Where is lab data recorded?
• Describe quality control
procedures.
Equipment Calibration
• Describe procedure for
calibrating turbidimeters.
. Describe procedures for
calibrating other equipment
(continuous chlorine and pH
monitors).
Description/Information
189
-------
MAINTENANCE DATA
A. Maintenance Program
Describe the plant maintenance program.
Topic
1 . Preventive Maintenance
> Describe equipment inventory
method (cards, computer).
• Describe maintenance scheduling
method (daily, weekly, monthly,
annual).
2. Corrective Maintenance
• Describe the work order system
(issuing orders/documentation).
• Describe priority setting
(relationship to process control
and plant performance needs).
• List major equipment out of
service within last 6 months.
3. Predictive Maintenance
• Describe methods used to
predict maintenance needs
(vibration, infrared analysis).
4. Housekeeping
. Does poor housekeeping detract
from plant performance/image?
Description/Information
190
-------
MAINTENANCE DATA
B. Maintenance Resources
Describe the available maintenance resources at the plant.
Topic
1. Equipment Repair and Parts
• Are critical spare parts stored at
the plant?
. Can vendors provide quick
response to spare parts needs?
. What is the policy on parts
procurement by staff?
2. Maintenance Expertise
. Describe staff expertise
(mechanical, electrical,
instrumentation).
. Does the staff use any contract
maintenance services? How
responsive are they to needs?
• Does staff develop and use
maintenance procedures?
3. Work Space and Tools
. Does the plant have adequate
work space and tools to perform
maintenance tasks?
4. Performance Monitoring
• How is maintenance performance
measured (time to complete
task, work order backlog)?
Description/Information
191
-------
FIELD EVALUATION DATA
A. Historical Water Production Data
1. Use the following table to determine the peak instantaneous operating flow for the plant.
Month/Year
Maximum
Daily Flow
Operating
Time Per Day
Flow During
Operation {1)
Instantaneous Peak
Flow (2)
111 If a plant operates less than 24 hr/day, flow during operation can be determined from the
equation below:
Q _QT 24hr
A T day
QA = Average flow during operation
QT = Total flow in 24-hour period
T = Time of plant operation, hours
121 Peak instantaneous flow through a plant is often different than the average flow due to
changing water demands that the plant must meet. The peak instantaneous flow during a
day can sometimes be obtained from plant logs (e.g., raw pump operation, rate change
time and flow).
192
-------
FIELD EVALUATION DATA
B. Water Usage
1. Determine the water usage per capita based on water production records and population seirved.
Water usage statistics for the United States are shown in the table below.
Qc = Usage per capita per day
QT = Total flow in 24-hour period
P = Population served
Population
Qc Avg.
Qc Peak
State
Alabama
Alaska-
Arizona
a
California
Connecticut
Delaware
Florida
Georgia
Hawaii
Use (qpcpd)
State
191
191
175
inn
120
124
146
160
180
[Nebraska
I Nevada
New Hampshire
New Mexico
nrk
North Carolina
Use (qpcpd)
I North Dakota
lohio
Oregon
174
85
184
1CC
107
114
127
164
Idaho
Illinois
163
154
Pennsylvania
Rhode Island
128
115
Indiana
Iowa
115
131
South Carolina
South Dakota
148
1C1
Kansas
144
Tennessee
148
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
128
147
81
165
119
136
I Texas
Utah
I Vermont
Washington
West Virginia
176
255
80
119
217
96
Minnesota
Mississippi
Missouri
Montana
105
127
131
164
Wisconsin
yoming,
Puerto Rico
Virgin Islands
118
188
115
63
Source: Solley, W.B. Preliminary Estimates of Water Use in the United States, 1995,
U.S. Geological Survey (1997).
193
-------
FIELD EVALUATION DATA
2. Determine unaccounted for water based on monthly or annual water production and meter records.
Unaccounted for water typically varies from 10 to 12 percent for new systems and 15 to 30 percent
for older systems (Metcalf and Eddy, Inc. 1991).
QT
Q% = % unaccounted
QT = Total plant water production for month or year
QM = Total metered water for month or year
QT _
QM _
Q* _
3. Determine backwash water percent based on volume of water filtered and volume of water used for
backwash. Typically, the amount of water used for backwash ranges for 2 to 6 percent for conven-
tional plants. Higher percentages can occur for direct filtration plants.
BW =
BW% = % backwash water
VF = Volume of water filtered
VBW = Volume of water used for backwash
VBW
BW%
194
-------
FIELD EVALUATION DATA
c. In-Plant Studies
Describe results of in-plant studies conducted during the CPE.
Topic
1 . Filter Media Evaluation
• Check media depth and type.
. Check media condition (presence
of chemicals/debris, mudballs,
worn media).
. Check support gravel level
(variation of less than 2 inches
acceptable).
2. Backwash Evaluation
• Check backwash rate (measure
rise rate in the filter versus time
and convert to backwash rate;
> 15 gpm/ft2 acceptable).
. Check bed expansion
> 20 percent acceptable).
Description/Information/Findings
.
195
-------
FIELD EVALUATION DATA
C. In-Plant Studies (cont.)
Describe results of in-plant studies conducted during the CPE.
Topic
2. Backwash Evaluation (cont.)
. Observe backwash procedure
(flow distribution, ramping of flow
rate, turbidity of water at end of
backwash).
3. Coagulant Dosage Evaluation
• Verify reported dose with actual;
measure liquid or dry feed rate
(Ib/min, mL/min) and convert to
dose (mg/L).
4. Turbidity Meter Evaluation
. Check meter calibration or
compare with calibrated meter.
Descri ption/l nformation/Fi ndi ngs
196
-------
FIELD EVALUATION DATA
C. In-Plant Studies (cont.)
Describe results of in-plant studies conducted during the CPE.
Topic
Descri ption/l nformation/Fi ndi ngs
197
-------
INTERVIEW DATA
A. Interview Guidelines
The following interview guidelines are provided to assist CPE providers with the interview process.
1. Conduct interviews with one staff person at a time in a private location.
• It is important to create a comfortable environment for the interview process to take place. Con-
fidentiality of the interview should be explained.
2. Keep the interview team size small.
The number of people included on each interview team should be kept to a minimum (e.g., 1 to 3)
to avoid overwhelming the person being interviewed. If more than one person is included on the
team, one person should be assigned as the lead interviewer.
3. Allow 30 to 45 minutes for each interview.
Interview times will vary depending on the personality of the individual being interviewed and the
number and type of issues involved. It is the responsibility of the interviewer to maintain the
focus on performance-related issues. Interviews can easily be detracted by individuals who find
an "open ear" for presenting grievances.
4. Explain the purpose of the interview and use of the information.
It is important for the people being interviewed to understand that any information obtained from
this process is only used to support identification of factors limiting performance (i.e., areas
impacting performance). The interview information is not used to place blame on specific indi-
viduals or departments.
5. Conduct interviews after sufficient information has been aathered from CPE activities.
• Utilize results and observations gained from the plant tour, performance assessment, major unit
process evaluation, and data collection activities to identify areas of emphasis during the inter-
views.
6. Proaress throuah the interview In a logical order.
For example, if an administrator is being interviewed, focus questions on administrative support,
then on design issues, followed by operation and maintenance capabilities,
7. Ask relevant auestions with respect to staff area of involvement.
• For example, when interviewing maintenance personnel, ask questions related to relevant topics
such as maintenance responsibilities, communication with supervisors, and administrative support
for equipment.
8. Ask open-ended auestions.
For example, a question such as "Are you aware of any design deficiencies with the current
plant? " would provide better information than a question like "Do you think that the flocculation
basin provides sufficient detention time for flocculation?".
198
-------
INTERVIEW DATA
9. Ask the auestions: don't aive the answers.
• The purpose of the interview is to gain the perspective of the person being interviewed. Ask the
question and wait for the response (i.e., don't answer your own question based on information
you may have received from previous activities). Rephrasing the question may sometimes be
necessary to provide clarity.
10. Repeat a response to a auestion for clarification or confirmation.
For example, the interviewer can confirm a response by stating, "If I understand you correctly,
you believe that the reason for poor plant performance during April was due to excessive algae
growth in the source water."
11. Avoid accusatory statements.
Accusatory statements will likely lead to defensiveness by the person being interviewed. Rather,
if an area of concern is suspected, ask questions that can confirm or clarify the situation.
12. Use the interview to clarify or confirm field information.
For example, if performance problems occurred during one month of the past year, ask questions
to clarify the perceived reasons for these problems.
13. Note specific responses that support factor identification.
During or following the interview, the interviewer may want to note or underline specific
responses that support the identification of possible factors limiting performance. This summary
can then be used during team debriefing and factor identification meetings.
199
-------
INTERVIEW DATA
B. Personnel Interview Form
Name Title
Time at plant Years of experience
Education/training/certification
Interview notes (concerns, recommendations in administration, design, operation, and maintenance):
200
-------
EXIT MEETING
A. Attendance List
Utility Name
Date
Name
Title/Position
Telephone No.
201
-------
EXIT MEETING
B. Mutiple Barrier Concept for Microbial Contaminant Protection
Coagulant
Addition
Variable
Quality
Source
Watsr
* »«•
•••I
Flocculation/Sedimentation
Barrier
Disinfection
Barrier
. Given a variable quality source water, the treatment objective is to produce a consistent, high quality
finished water.
. Protozoan parasites, such as Giardia and Cryptosporidium, are found in most source waters; however,
it is difficult to quantify their presence and assess their viability.
. Microbial pathogens in the source water, such as protozoan parasites, bacteria, and viruses, can be
physically removed as particles in treatment processes and inactivated through disinfection.
. Multiple barriers are provided in a treatment plant to remove or inactivate microbial pathogens.
. Key treatment barriers include flocculation/sedimentation, filtration, and disinfection.
. Since measurement of protozoan parasites is difficult, surrogate parameters, such as turbidity, particle
counting, and pathogen inactivation, are used to assess the performance of each barrier.
202
-------
EXIT MEETING
C. Optimization Performance Criteria
A summary of performance criteria for surface water treatment plants to provide protection against
microbial contaminants is presented below:
1. Minimum Data Monitoring Requirements
• Daily raw water turbidity
• Settled water turbidity at 4-hour time increments from each sedimentation basin
• On-line (continuous) turbidity from each filter
• One filter backwash profile each month from each filter
2. Individual Sedimentation Basin Performance Criteria
Settled water turbidity less than 1 NTU 95 percent of the time when annual average raw water
turbidity is less than or equal to 10 NTU
Settled water turbidity less than 2 NTU 95 percent of the time when annual average raw water
turbidity is greater than 10 NTU
3. Individual Filter Performance Criteria
• Filtered water turbidity less than 0.1 NTU 95 percent of the time (excluding 1 5-minute period
following backwashes) based on the maximum values recorded during 4-hour time increments
• Maximum filtered water measurement of 0.3 NTU
Initiate filter backwash immediately after turbidity breakthrough has been observed and before
effluent turbidity exceeds 0.1 NTU.
Maximum filtered water turbidity following backwash of 0.3 NTU
Maximum backwash recovery period of 15 minutes (i.e., return to less than 0.1 NTU)
> Maximum filtered water measurement of less than 10 particles (in the 3 to 18 //m range) per milli-
liter (if particle counters are available)
4. Disinfection Performance Criteria
• CT values to achieve required log inactivation of Giardia and virus
203
-------
Appendix G
Example CPE Report
205
-------
Results of the
Comprehensive Performance Evaluation
of Water Treatment Plant No. 005
Prepared by:
Prepared for:
206
-------
Mailing Address:
Date of Site Visit:
Utility Personnel:
CPE Team:
Site Visit Information
207
-------
Table of Contents
Paoe No.
INTRODUCTION 210
FACILITY INFORMATION 211
PERFORMANCE ASSESSMENT 212
MAJOR UNIT PROCESS EVALUATION 216
PERFORMANCE LIMITING FACTORS 218
Alarms (Design) A 218
Process Flexibility (Design) A 218
Policies (Administration) A 218
Insufficient Time on the Job (Operation) A 218
Process Instrumentation/Automation (Design) B 218
Presedimentation (Design) B 219
EVALUATION FOLLOW-UP 219
REFERENCES 219
208
-------
List of Figures
FIGURE 1 Comprehensive Performance Evaluation methodology.
FIGURE 2 Water treatment flow schematic.
FIGURE 3 Daily maximum plant influent water turbidity.
FIGURE 4 Daily maximum finished water turbidity.
FIGURE 5 Filter effluent turbidity profile after backwash.
FIGURE 6 Major unit process evaluation.
FIGURE 7 Process evaluation for individual treatment unit.
Page No.
210
211
213
214
215
216
217
List of Tables
TABLE 1 Frequency Analysis of Raw Water Turbidity
TABLE 2 Frequency Analysis of Finished Water Turbidity
213
215
209
-------
Introduction
The Composite Correction Program (CCP) (1 ) is an
approach developed by the U. S. Environmental
Protection Agency and Process Applications, Inc.
to improve surface water treatment plant perform-
ance and to achieve compliance with the Surface
Water Treatment Rule (SWTR). Its development
was initiated by Process Applications, Inc. and the
State of Montana (2), who identified the need for
a program to deal with performance problems at
their surface-supplied facilities. The approach
consists of two components, a Comprehensive
Performance Evaluation (CPE) and Comprehensive
Technical Assistance (CTA).
The methodology followed during a CPE is
described in Figure 1. A comprehensive assess-
ment of the unit process design, administration
and maintenance support is performed to establish
whether a capable plant exists. Additionally, an
assessment is made on the plant staff's ability to
apply process control principles to a capable plant
to meet the overall objective of providing safe and
reliable finished water. The results of this
assessment approach establish the plant capability
and a prioritized set of factors limiting perform-
ance. Utility staff can address all or some of the
identified factors, and improved performance can
occur as the result of these efforts. A CTA is
used to improve performance of an existing plant
when challenging or difficult-to-address factors are
identified during the CPE. Therefore, the CCP
approach can be utilized to evaluate the ability of a
water filtration plant to meet the turbidity and
disinfection requirement of the SWTR and then to
facilitate the achievement of cost effective compli-
ance.
In recent years, the CCP has gained prominence as
a mechanism that can be used to assist in opti-
mizing the performance of existing surface water
treatment plants to levels of performance that
exceed the requirements in the SWTR. The cur-
rent standards do not always adequately protect
against some pathogenic microorganisms, as evi-
denced by recent waterborne disease outbreaks.
Producing a finished water with a turbidity of
<0.1 NTU provides much better protection
against pathogens like Cryptosporidium (3,4,5,
6,7,8,9,10,11 ), the microorganism responsible for
a large outbreak of Ctyptosporidiosis in Milwaukee
in April 1993, where 403,000 people became ill
and at least 79 people died.
USEPA has chosen to use the CCP approach to
evaluate selected surface water treatment plants in
this region. Water Treatment Plant No. 005 was
selected as the first candidate for a CPE. This
plant has experienced difficulties with continuously
meeting the turbidity requirements of the SWTR,
and the water system manager and staff
expressed interest in receiving assistance with cor-
recting this situation.
FIGURE 1. Comprehensive Performance Evaluation methodology.
SafaEeJiahle. Finished
Operation (Process Control)
Capable Plant
Design
210
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The following report documents the findings of the
CPE conducted at Water Treatment Plant No. 005.
The CPE identifies and prioritizes the reasons for
less-than-optimum performance. The CPE may be
followed by the second phase of the CCP, Com-
prehensive Technical Assistance (CTA), if appro-
priate.
Facility Information
A flow schematic of Water Treatment Plant
No. 005 is shown in Figure 2. The water source
for the plant is Clear Creek. Staff reported that
turbidity in the creek reaches a maximum level of
50 - 80 NTU. The Clear Creek Basin can be
characterized as mountainous and forested.
Sources of potential contamination include wildlife
and human sources (e.g., recreation use, camping
etc.).
The intake for the treatment plant is located in
Clear Creek upstream of a small diversion dam.
The turbidity in the raw water pipeline has not
been recorded regularly since the treatment plant
began operation. Limited raw water pipeline tur-
bidity data from before plant start-up was
reviewed during the CPE. The data indicate that
turbidity in the raw water pipeline was typically
low (i.e., < 1.5 NTU) with some peaks in the
spring that were less than 5 NTU. About 100
cubic yards of sediment is dredged and removed
at two-year intervals in the vicinity of the intake,
upstream of the diversion dam. Settling of par-
ticulates at this location may partially account for
the low raw water turbidity values observed. The
utility is also constructing a dam upstream of the
intake; and, as a result, even less raw water tur-
bidity variations are expected in the future.
FIGURE 2. Water treatment flow schematic.
System
211
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About 6 cfs of water flows by gravity from the
intake through about four miles of 14-inch
diameter ductile iron pipe to a utility-owned
hydroelectric power generating station near the
water treatment plant. After the hydroelectric
station, about 4 cfs flows back into Clear Creek
and the remaining 2 cfs flows through two large
presedimentation ponds. Detention time through
these ponds is estimated to be about 14 days. A
raw water pump station located beside the lower
pond includes four constant speed raw water
pumps, each with a 700 gpm capacity.
The amount of water that can be run through the
presedimentation ponds and discharged to the
creek is limited by the capacity of the Parshall
flume on the overflow of the lower pond. Also,
there are no provisions to bypass an individual
pond to reduce the detention time. The ponds can
be bypassed by directing the raw water to the
pump station intake; however, this results in the
bypassing of the hydroelectric station. The utility
is planning to install another pipeline from the
hydroelectric station to the raw water pumping
station before the spring runoff occurs. This will
allow the ponds to be bypassed without interfering
with the hydroelectric station operation.
The water treatment plant began operation in
August 1996. Prior to that, chlorination was
provided after the settling ponds before entering
the distribution system. The plant has a reported
firm design capacity of about 3 MOD. Major
treatment components include chemical feed
equipment, four package treatment trains consist-
ing of an upflow clarifier and filter basins, a
110,000 gallon clearwell, and a 600,000 gallon
finished water storage tank. Each of the upflow
clarifier and filter units has a reported capacity of
1 MGD. The plant is designed to operate at
1 MGD incremental flow rates with one raw water
pump dedicated to each treatment train in opera-
tion. Unique characteristics of the plant are sum-
marized as follows.
• Large presedimentation ponds prior to treat-
ment.
• Static mixer for coagulant mixing.
. Chemical feed capability: alum, polymer, soda
ash, powdered activated carbon, chlorine.
. Upflow clarifiers with gravel media (1 to 5 mm
size).
. Mixed media filters.
. Filter-to-waste capability set by a common
control valve to 1 MGD. (NOTE: This flow
rate is not easily adjusted and limits the flexi-
bility to change the individual treatment train
flow rate to a value other than 1 MGD.)
. Two continuously monitoring particle counters
on filter effluent (one shared by two trains).
. Clearwell with intra-basin baffles
Performance Assessment
During the CPE, the capability of the Water Treat-
ment Plant No. 005 was evaluated to assess
whether the facility, under existing conditions,
could comply with the turbidity and disinfection
requirements that are used to define optimized
performance. Optimized performance, for pur-
poses of this CPE, represents performance criteria
that exceeds the SWTR requirements. Optimized
performance would require that the facility take a
source water of variable quality and consistently.
produce a high quality finished water. Multiple
treatment processes (e.g., flocculation, sedimenta-
tion, filtration, disinfection) are provided in series
to remove particles, including microbial pathogens,
and provide disinfection to inactivate any remain-
ing pathogens.
Water Treatment Plant No. 005 utilizes a package
water treatment process that includes combined
flocculation/sedimentation in an upflow clarifier
and filtration. Each of the available processes rep-
resents a barrier to prevent the passage of micro-
bial pathogens through the plant. By providing
multiple barriers, any microorganisms passing one
process can be removed in the next, minimizing
the likelihood of microorganisms passing through
the entire treatment system and surviving in water
supplied to the public. The role of the water
treatment operator is to optimize the treatment
processes (i.e., barriers) under all conditions
because even temporary loss of a barrier could
result in the passage of microorganisms into the
distribution system and represents a potential
health risk to the community.
A major component of the CPE process is an
assessment of past and present performance of
the plant. This performance assessment is
intended to identify if specific unit treatment
212
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processes are providing multiple barrier protection
through optimum performance. The performance
assessment is based on data from plant records
and data collected during special studies per-
formed during the CPE.
Specific turbidity performance targets were used
during this assessment. These specific perform-
ance targets include:
• Sedimentation - turbidity of less than 1 NTU
95 percent of the time, since average annual
raw water turbidity is less than 10 NTU.
• Filtration - individual filter turbidity less than
0.1 NTU 95 percent of the time (excluding 15-
minute period following backwash); also,
maximum filtered water turbidity following
backwash of 0.3 NTU.
• Disinfection - CT values to achieve required log
Giardia cyst and virus inactivation.
A plant influent turbidimeter and strip chart
recorder are provided, but the plant operators do
not routinely record daily influent water turbidity in
their operating log. The plant influent turbidity
strip charts for the past year were reviewed during
the evaluation. A frequency analysis of these data
is summarized in Table 1. As indicated, the raw
water turbidity is less than or equal to 4 NTU 95
percent of the time. Maximum daily plant influent
turbidity varied from less than 1 NTU to 10 NTU,
as shown in Figure 3.
TABLE 1. Frequency Analysis of Raw Water
Turbidity
Percentile
50
75
90
95
Average
Raw Water
NTU*
2.2
3.0
3.6
4.0
2.6
*Daily maximum value
The turbidimeter is located a long distance from
the influent pipe. A significant number of brief (a
few minutes to less than 1 hour) turbidity spikes
were noted on the strip chart. A special study
would be required to determine the cause of these
brief influent turbidity spikes. Influent turbidity
during the CPE was less than 1 NTU.
FIGURE 3. Daily maximum plant influent water turbidity.
213
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The finished water turbidimeter is located at the
outlet of the 600,000 gallon finished water stor-
age tank. This meter has a strip chart recorder,
and operators routinely record this data for water
quality reporting purposes.
The plant operators do not routinely sample and
measure turbidity after the upflow clarifiers. Dur-
ing the CPE, turbidities of 0.56 to 0.71 NTU were
measured between the upflow clarifier and the fil-
ter over a two-hour period. During the same
period the plant influent turbidity ranged from 0.5
to 0.7 except for a 15-minute spike from 3 to
10 NTU after a brief filter shutdown. Because of
the low influent water turbidity conditions during
the CPE and the lack of historical turbidity data at
the clarifier outlet, the ability of the plant to meet
the 1 NTU turbidity goal on a long-term basis
could not be determined.
The plant does not have on-line turbidimeters for
monitoring turbidity following individual filters, and
plant operators do not routinely collect grab sam-
ples to measure turbidity at this location. Two on-
line particle counters are available for monitoring
filter performance; however, staff have experi-
enced operating problems with at least one of the
units. To assess historical plant performance, tur-
bidity values from after the treated water storage
tank were used. The daily maximum finished
water turbidity for the previous 12 months is
shown in Figure 4. The results of a frequency
analysis of the finished water data are shown in
Table 2 and indicate that 95 percent of the time
the filtered water turbidity was less than
0.87 NTU.
During several months, plant performance did not
meet the turbidity requirement of the SWTR (i.e.,
<0.50 NTU 95 percent of the time on monthly
basis). From April through June, filtered water
turbidity consistently exceeded the regulated limit
of 0.50 NTU, Plant staff reported that this period
of poor performance was due to a bad batch of
alum and poor water quality from the ponds. A
large amount of algae or other filamentous material
from the ponds caused clogging problems on the
media support screens of the upflow clarifiers for
several weeks. This material was cleaned manu-
ally with great difficulty, and during the worst
period cleaning was required on a daily frequency.
Hand-cleaned screens have been installed on the
raw water pump intakes in the lower pond to
assist with removing this material before it reaches
the treatment units. It is also possible that post
flocculation may have occurred in the clearwell
and finished water storage tank during this period.
FIGURE 4. Daily maximum finished water turbidity.
214
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TABLE 2. Frequency Analysis of Finished Water
Turbidity
Percent! le
50
75
90
95
Average
Finished Water
NTU*
0.16
0.32
0.55
0.87
0.33
'Daily maximum value
Although significant improvement in performance
has recently occurred, the plant d i d not achieve
the optimized filtered water turbidity target of less
than 0.1 NTU during the past year. This perform-
ance allows an increased opportunity for patho-
gens, such as Cryptosporidium oocysts, to pass
into the public water supply.
During the CPE a special study was conducted on
the filter media, backwash procedure, and per-
formance of a filter following a backwash. Prior to
backwashing, filter unit #2 was drained to allow
physical observation of the filter media. The total
depth of the mixed media was consistently about
31.5 inches. Of this mixed media depth, about 18
inches was anthracite. Inspection of the media at
and below the surface showed that the media was
very clean. During the backwash, a filter bed
expansion of 21.8 percent was calculated, which
is within the acceptable range of 20 to 25%.
Immediately after completion of the filter back-
wash, the filtered water turbidity was measured
periodically for about 35 minutes. These data are
shown in Figure 5. The current procedure is to
filter to waste for ten minutes after the end of the
backwash cycle. As indicated by the performance
graph, the filter did not meet the backwash optimi-
zation criteria of a maximum turbidity spike of
0.3 NTU and return to less than 0.1 NTU within
15 minutes.
In summary, performance data for the last year
show that Water Treatment Plant No. 005 has not
been in compliance with the SWTR on a consistent
basis. In addition, the plant has not met the opti-
mized performance goal of 0.1 NTU for filtered
water. Consequently, this performance assess-
ment indicates that the water system is at risk of
passing microbial pathogens to consumers.
FIGURE 5. Filter effluent turbidity profile after backwash.
0.45
0.40 ••
15 20
Minutes After Backwash
25
30
35
215
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Major Unit Process Evaluation
Major unit processes were assessed with respect
to their capability to provide consistent perform-
ance and an effective barrier to passage of micro-
organisms on a continuous basis. The perform-
ance goal used in this assessment for the filtration
process was a settled water turbidity of less than
2 NTU and a filtered water turbidity of less than
0.1 NTU. Capabilities of the disinfection system
were based on the USEPA guidance manual (12)
requirements for inactivation of Giardia and
viruses.
Since the plant's treatment processes must pro-
vide an effective barrier at all times, a peak instan-
taneous operating flow is typically determined.
The peak instantaneous operating flow represents
the maximum flow rate that the unit processes are
subjected to, which represents the hydraulic con-
ditions where the treatment processes are the
most vulnerable to the passage of microorganisms.
If the treatment processes are adequate at the
peak instantaneous flow, then the major unit proc-
esses are projected to be capable of providing the
necessary effective barriers at lower flow rates.
Water Treatment Plant No. 005 has a maximum
raw water pumping capacity of 4 MGD. The plant
was designed for a maximum treatment capacity
of 3 MGD with one treatment unit out of service.
A peak instantaneous flow rate of 3 MGD is used
for the major unit process evaluation, based on the
highest instantaneous flow rate reported by the
staff.
Major unit process capability was assessed by
projecting treatment capacity of each major unit
process against the peak instantaneous flow rate.
The major unit process evaluation for the entire
treatment plant is shown in Figure 6. The unit
processes evaluated are shown on the left side of
the graphs, and the flow rates against which the
processes were assessed are shown across the
top. Horizontal bars on the graph represent the
projected peak capability of each unit process to
achieve the desired optimized process perform-
ance. These capabilities were projected based on
the combination of treatment processes at the
plant, the CPE team's experience with other simi-
lar processes, industry guidelines, and regulatory
standards. The shortest bar represents the unit
process which limits plant capability the most rela-
tive to achieving the desired plant performance.
FIGURE 6. Major unit process evaluation.
0.0 0.5
1.0
Water Flow Rate (MGD)
1.5 2.0 2.5
3.0
3.5
4.0
Floe/Sedimentation (1)
Filtration (2)
Disinfection (3)
Peak
Instantaneous
Flow
(1) Surface area = 280 ft*; rated at 8.0 gpm/ft2, upflow clarifier with rock gravel media
(2) Surface area = 580 ft*; rated at 4 gpm/ftf; mixed media
(3) Volume = 98,000 gal; total 3-log Giardia inactivation/removal required; assume 2.5-log
removal allowed through conventional plant credit and OS-log required by disinfection;
pH = 7.5; temp = 0.5°C; chlorine residual = 1.8 mg/L; T10/T = 0.7; 3 ft minimum
cleatwell depth
276
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The major unit processes evaluated were the
upflow clarifiers (flocculation and sedimentation),
filtration, and disinfection processes. Criteria used
to assess each major unit process are described in
the notes below the graph.
The upflow clarifiers were rated based on their
surface overflow rate. Typically, conventional
sedimentation basin capability is rated based on a
surface overflow rate of 0.5 to 0.7 gpm/ft2. A
surface overflow rate of 10 gpm/ft2 is used by the
package plant manufacturer for the design rating
of their upflow clarifier units. Because of the
combined flocculation and sedimentation function
and the short detention time of these units, they
were rated based on an overflow rate of
a gpm/ft2. This produced a combined floccula-
tion/sedimentation capability rating of 3.23 MGD
when using all four treatment units.
The filtration process was rated based on a load-
ing rate of 4 gpm/ft2 and use of all four filters.
These criteria resulted in a combined filtration
capability of 3.23 MGD.
The disinfection process was assessed based on
USEPA Surface Water Treatment Rule require-
ments for inactivation of 3-log of Giardia cysts and
4 log of viruses. The Giardia removal/inactivation
is the most stringent criteria; consequently, it was
used as the basis of the disinfection evaluation. A
well-operated conventional filtration plant is
allowed a 2.5-log removal credit for Giardia cysts,
and the remaining 0.5-log removal is achieved by
meeting specified CT requirements associated with
chemical disinfection. CT is the disinfectant con-
centration (C) in mg/L multiplied by the time (T) in
minutes that the water is in contact with the disin-
fectant. The required CT value was obtained from
the USEPA guidance manual (3), using typical
plant values for free chlorine residual (i.e.,
1 .0 mg/L) and pH (i.e., 7.5) and a worst case
water temperature of 0.5°C. The volume of the
clearwell was adjusted for the minimum operating
depth of 3 feet. A T10/T ratio of 0.70 was used
because of the superior baffling conditions in the
clearwell. Under this scenario, the disinfection
process is capable of treating 3.44 MGD, using a
required free chlorine CT value of 46 mg/L-min.
The results of the major unit process evaluation
indicate that the plant should be capable of treat-
ing the peak instantaneous flow rate of about
3.2 MGD with four treatment trains in service (i.e.,
0.8 MGD per train). However, the control of the
plant is set up so that each treatment train
operates at a constant flow rate of 1 MGD (see
Figure 7), and flexibility does not exist to easily
operate each train at lower flow rates without
modifying the filter to waste piping from the
filters.
FIGURE 7. Process evaluation for individual treatment unit.
o.o
Water Flow Rate (MGD)
0.5 1.0
1.5
Floe/Sedimentation (1)
Filtration (2)
Peak
Instantaneous
Flow
(1) Surface area = 70 ft2; rated at 8.0 gpm/ft2; upflow clarifier with gravel media
(2) Surface area = 140 ft2; rated at 4 gpm/ft2; mixed media
277
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The major unit process evaluation indicates that
the current practice of operating individual treat-
ment units at a constant flow rate of 1 MGD, as
required by the design and control system, may be
contributing to the less-than-optimum performance
of the flocculation/sedimentation and filtration
processes.
Performance Limiting Factors
The areas of design, operation, maintenance, and
administration were evaluated in order to identify
factors which limit performance. These evalua-
tions were based on information obtained from the
plant tour, interviews, performance and design
assessments, special studies, and the judgment of
the evaluation team. Each of the factors was
classified as A, B, or C according to the following
guidelines:
A — Major effect on a long term, repetitive basis
B — Minimal effect on a routine basis or major
effect on a periodic basis
C — Minor effect
The A and B factors were prioritized as to their
relative impact on performance and are summa-
rized below. In developing this list of factors lim-
iting performance, 50 potential factors were
reviewed; and their impact on the performance of
Water Treatment Plant No. 005 was assessed.
The evaluation team identified six factors that are
limiting plant performance. Numerous other fac-
tors were not felt to be affecting plant perform-
ance. The factors and the findings that support
their selection are summarized below in prioritized
order.
Alarms (Design) A
• The plant does not have alarm and shutdown
capability on chlorine feed, chlorine residual,
influent turbidity and finished water turbidity.
Process Flexibility (Design) A
Inability to automatically change the filter to
waste flow rate to values other than 1 MGD.
(NOTE: This lack of flexibility limits the flow
rate of the individual treatment trains, since
the plant flow rate must be 1 MGD to match
the filter to waste flow rate of 1 MGD; other-
wise, the water level in a filter changes.)
• No ability to feed filter aid polymer to the fil-
ters. (NOTE: This flexibility can be used to
enhance filter performance, especially during
times when clarifier performance is less than
optimum.)
. Inability to gradually increase and decrease
backwash flow rate. (NOTE: This flexibility
provides better cleaning of the filter media,
less opportunity for loss of media, and better
re-stratification of the media following back-
wash.)
Policies (Adminis tra tion) A
• Lack of established performance goals for the
plant, such as 0.1 NTU filtered water turbidity,
that would provide maximum public health
protection and associated support to achieve
these performance goals.
Insufficient Time on the Job (Operation) A
• No sampling and evaluation of upflow clarifier
performance.
• Inadequate testing to optimize coagulant type
and dosages. (NOTE: Some jar testing was
completed by staff; however, standard testing
procedures were not followed to determine
optimum dosages.)
• No monitoring of individual filter turbidity.
• Excessive caution on use of the creek source
to achieve optimized performance.
• Starting "dirty" filters without backwashing or
using filter to waste.
• Non-optimized feed point for flocculant aid
addition. (NOTE: Flocculant aid products are
typically fed at a location with gentle mixing to
avoid breaking the long-chain organic mole-
cules.)
Process Instrumen ta tion/Automa tion (Design) B
• No turbidimeters are located on individual fil-
ters and creek source (i.e., at turbine).
218
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Plant is designed to automatically start and
stop operation based on storage tank level and
upflow clarifier backwash requirements.
(NOTE: Without initiating a filter backwash or
the filter to waste mode after each shutdown,
the potential exists to pass trapped particles
(i.e., potential pathogens) through the plant
due to hydraulic surging.)
Location of influent turbidity sample line rela-
tive to the monitor cell may cause inaccurate
readings.
Presedimen ta tion (Design) B
• Long detention time and subsequent low turn-
over contributes to excessive algae growth
and poor water quality.
• Lack of flexibility to operate one, or portion of
one, presedimentation pond to reduce deten-
tion time and increase turnover.
• Lack of flexibility to bypass ponds without
bypassing the turbine. (NOTE: A new bypass
is under construction which will provide this
flexibility.)
• Limited ability to maintain high turnover
through ponds when not in use because of
restriction in Parshall flume from pond 2 to
creek.
Evaluation Follow-Up
The potential exists to achieve optimized perform-
ance goals and, therefore, enhance public health
protection with Water Treatment Plant No. 005.
Implementation of a Comprehensive Technical
Assistance (CTA) project by a qualified facilitator
has been demonstrated to be an effective
approach to achieve optimum performance goals
(13). Through a CTA project, the performance
limiting factors identified during the Comprehen-
sive Performance Evaluation would be addressed
in a systematic manner. A partial list of potential
CTA activities that could be implemented by a
facilitator and plant staff is presented below:
• Facilitate development of optimization per-
formance goals by the city administration to
provide adequate direction and support to
operation and maintenance staff.
Establish a process control program based on
prioritized data collection, database develop-
ment, data and trend interpretation, and proc-
ess adjustments.
Provide technical guidance on use of the creek
source versus the presedimentation ponds
during seasonal water quality changes.
Facilitate special studies with plant staff to
assist them with optimizing plant performance
and establishing the need for minor plant modi-
fications.
Provide training to assist operators with opti-
mizing coagulant type and dosages.
References
1. Renner, R.C., B.A. Hegg, J.H. Bender, and
E.M. Bissonette. February 1991. Handbook -
Optimizing Water Treatment Plant Perform-
ance Using the Composite Correction Pro-
gram. EPA 625/6-91/027. Cincinnati, OH:
USEPA.
2. Renner, R.C., B.A. Hegg, and D.F. Fraser.
February 1989. "Demonstration of the Com-
prehensive Performance Evaluation Technique
to Assess Montana Surface Water Treatment
Plants." Association of State Drinking Water
Administrators Conference. Tucson, AZ.
3. AWWA Statement of Policy. 1968. "Quality
Goals for Potable Water." Jour.A WWA,
60(121:1317. Denver, CO.
4. AWWA White Paper. 1995. "What Water
Utilities Can Do to Minimize Public Exposure
to Cryptosporidium in Drinking Water."
AWWA Mainstream. Denver, CO.
5. Logsdon, G.S. and E.G. Lippy. December
1982. "The Role of Filtration in Preventing
Waterborne Disease. " Jour.AWWA:654.
Denver, CO.
6. USEPA Water Engineering Research Labora-
tory. 1985. Project Summary - Filtration of
Giardia Cvsts and Other Substances:
Volume 3 - Rapid Rate Filtration. EPA/600/
S2-85/027. Cincinnati, OH: USEPA.
219
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7. Logsdon, G.S., L. Mason, and J.B. Stanley,
Jr. 1988. "Troubleshooting an Existing
Treatment Plant." In Proc. of A WWA Semi-
nar - Filtration: Meeting New Standards:
109-1 25. Denver, CO.
8. Consonery, P.J., et. al. November 1996.
"Evaluating and Optimizing Surface Water
Treatment Plants: How Good is Good
Enough." Paper presented at AWWA Water
Quality Technology Conference. Boston, MA.
11.
12.
9. Nieminski, E.G., et. al. 1995. "Removing
Giardia and Cryptosporidium by Conventional
Treatment and Direct Filtration." Journal 13.
AWWA, 87(9):96. Denver, CO.
10. West, T., P. Daniel, P. Meyerhofer, A.
DeGraca, S. Leonard, and C. Gerba. 1994.
"Evaluation of Cryptosporidium Removal
Through High Rate Filtration." In Proceedings
of 1994 AWWA Annual Conference - New
York. NY. AWWA. Denver, CO.
Patania, N.L., et. al. 1996. "Optimization of
Filtration for Cyst Removal." Denver, CO:
AWWARF.
Guidance Manual for Compliance With the
Filtration and Disinfection Requirements for
Public Water Systems Using Surface Water
Sources. 1989. USEPA Office of Drinking
Water. Washington, D.C.
Schwarz, C., J.H. Bender, and, B.A. Hegg.
December 1997. "Final Report - Comprehen-
sive Technical Assistance Project - City of
Greenville Water Treatment Plant. " Texas
Natural Resource Conservation Commission,
220
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Appendix H
Example CPE Scheduling L e tier
221
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April 6, 1998
Chairman/Mayor/Public Works Director
Water Authority/City/Town
RE: Evaluation of the Water Authority/City/Town Water Treatment Plant
May 18-21, 1998
Dear Mr./Ms.
You were recently contacted by of the (regulatory agency) regarding an
evaluation of your water treatment facility. This letter is intended to provide you with some information
on the evaluation and describe the activities in which the Water Authority/City/Town will be
involved. The evaluation procedure that will be used at your facility is part of an overall water treatment
optimization approach called the Composite Correction Program.
The Composite Correction Program (CCP) was developed by the U. S. Environmental Protection Agency
and Process Applications, Inc. to optimize surface water treatment plant performance for protection
against microbial contaminants such as Giardia and Cryptosporidium. The approach consists of two com-
ponents, a Comprehensive Performance Evaluation (CPE) and Comprehensive Technical Assistance (CTA).
The first component, the Comprehensive Performance Evaluation, will be conducted at your facility the
week of . During the CPE, all aspects of your water treatment administration, design,
operation, and maintenance will be reviewed and evaluated with respect to their impact on achieving
optimized performance.
The evaluation will begin with a brief entrance meeting on Monday, May 18, 1998 at approximately
2:00 P.M. The purpose of the entrance meeting is to discuss with the plant staff and administrators the
purpose of the evaluation and the types of activities occurring during the next three days. Any questions
and concerns regarding the evaluation can also be raised at this time. It is important that the plant
administrators and those persons responsible for plant budgeting and planning be present because this
evaluation will include an assessment of these aspects of the plant. Following the entrance meeting,
which should last approximately 30 minutes, the plant staff will be requested to take the evaluation team
on an extensive plant tour. After the plant tour, the team will begin collecting performance and design
data. Please make arrangements so that the monitoring records for the previous 12 months, operating
records, and any design information for the plant are available for the team. Also, a continuous recording
on-line turbidimeter will be installed on one or more of your filters. Sample taps to accomodate this con-
nection should be available.
On Tuesday, the evaluation team will be involved in several different activities. The major involvement of
the plant staff will be responding to the evaluation team's questions on plant performance and operation
and maintenance practices. Several special studies may also be completed by the team to investigate the
performance capabilities of the plant's different unit treatment processes. Requests to inspect filter media
and monitor filter backwashes will be coordinated with staff to minimize the impact on plant operation.
Also on Tuesday, a member of the evaluation team will meet with the administrators to review the
administrative policies and procedures and financial records associated with the plant. We would like to
review your water treatment budget for the previous and current fiscal years. We would expect that most
of this information would be available in your existing accounting system.
222
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April 6, 1998
Page 2
We request that the plant staff and administrators be available for interviews either Tuesday afternoon or
Wednesday morning. We will be flexible in scheduling these interviews around other required duties of
you and your staff. Each of the interviews will require about 30 to 45 minutes of time.
We are anticipating that an exit meeting will be held on Thursday morning at 8:30 A.M., and it will last
about 1 hour. During the exit meeting, the results of the evaluation will be discussed with all of those
who participated. The performance capabilities of the treatment processes will be presented, and any fac-
tors found to limit the performance of the plant will be discussed. The evaluation team will also answer
any questions regarding the results of the evaluation. The results presented in the exit meeting will form
the basis of the final report, which will be completed in about one month.
We look forward to conducting the CPE at your facility. If you have any questions prior to the evaluation,
please don't hesitate to contact us.
Very truly yours,
Evaluation Team Contact
223
-------
Appendix I
Example Special Study
225
-------
Example Special Study
(as developed by CTA facilitator and plant staff prior to implementation)
I. Hypothesis
A. Increasing the ferric chloride dosage for low turbidity water (< 5.0 NTU) will improve the
finished water turbidity and increase plant stability.
B. Increasing the ferric dosage may decrease alkalinity below level to maintain finished water
pH target.
II. Approach
A. Conduct series of jar tests using established jar testing guidelines that vary ferric chloride
dosages (start with 0.5 mg/L increments and bracket down to 0.1 mg/L).
B. Add filter aid at the end of the flocculation time to simulate plant dosage (up to 0.1 mg/L).
C. Measure pH, alkalinity, temperature and turbidity of raw and finished water.
D. Document and interpret test results.
E. Test optimum dosage at full plant scale (pilot mode where filtered water is directed to
waste).
F. Measure same parameters as above.
G. If results indicate alkalinity limitation is necessary (finished water alkalinity c 20 mg/L),
conduct jar tests with soda ash addition.
III. Duration of Study
A. Two weeks to complete jar and full-scale testing.
IV. Expected Results
A. Improved finished water turbidity and increased plant stability at higher ferric chloride dos-
ages.
B. Deficiency in finished water alkalinity.
C. Loss of finished water pH.
D. Potential change in primary coagulant.
E. Potential need for alkalinity (soda ash) addition.
V. Conclusions
A. To be compiled in summary report after completion of study.
VI. Implementation
A. To be determined after completion of study.
226
-------
Appendix J
Example Operational Guideline
227
-------
Example Operational Guideline
Subject: Process Control Data Collection Number: 5
Objective: To establish a data collection method Date Adopted: 4/29/97
Date Revised:
Measure and record the following water quality, chemical usage, and flow data at the
frequency noted.
A. Raw water parameters (measure/record once per day):
1. Plant flow rate - MGD (8:00 a.m. to 8:00 a.m.)
2. Raw turbidity - 7 days per week
3. pH - units - 7 days per week
4. Alkalinity - mg/L - 5 days per week
5. Temperature - °C - 7 days per week
B. Chemical usage data (record once per day):
1. Coagulant use - gal/day
2. Coagulant batch density - Ib/gal
3. Filter aid use - gal/day
4. Filter aid batch density - Ib/gal
5. Chlorine use - Ib/day
6. Orthophosphate use - Ib/day
C. Finished water parameters (measure/record once per day, unless noted otherwise):
1. Alkalinity - mg/L - 5 days per week
2. pH - 7 days per week
3. Free chlorine residual - mg/L - 7 days per week (minimum value for day from chart)
4. Turbidity - NTU - value at established 4-hour increments
Individual sedimentation basin turbidity.
A. Collect samples once each 4-hour period from the effluent of each basin and use lab
turbidimeter to measure turbidity.
Individual filter monitoring data collection methods.
A. Circular recording charts will be used for turbidity monitoring.
1. Individual turbidity charts are located on top of the individual turbidity monitors.
2. Twenty-four hour charts will be used.
3. When changing charts, record the "change chart time" for the 24-hour period.
B. Data to record from individual filter charts.
1. Start of all backwashes (note time and record on chart).
2. Return to service after all backwashes (note time and record on chart).
3. Backwash turbidity spike (highest turbidity value after filter is back on-line).
4. Recovery turbidity (turbidity 15 minutes after filter placed back in service).
5. Highest turbidity recorded every 4 hours for each individual filter, excluding
backwash spike and recovery turbidities.
228
-------
Process Control Data Collection (Continued)
IV. Utilize the process control data entry form below for data recording.
A. Complete the data entry form once per day, 7 days per week.
Enter daily data into computer database program and print out daily report.
B.
C.
At the end of each month, print monthly process control report from the database program
and distribute as follows:
1. Public Works Director
2. Monthly process control file in filing cabinet
3. Post copy on plant bulletin board
Water Treatment Plant Process Control Data Entry Form
Parameter
Date
Flow rate
Raw turbidity
RawpH
Raw alkalinity
Raw temperature
Coagulant daily use
Coaq. batch density
Filter aid dally use
Turbidity Data
Max. Sedimentation 1
Max. Sedimentation 2
Max. fitter 1 turbidity
Max. filter 2 turbidity
Max. filter 3 turbidity
Max. filter 4 turbidity
Finished turbidity
Post Backwash Data
BW turbidity spike
Turb. 1 5 min, on-line
Units
m/d/y
MOD
NTU
units
mg/L
C
qa I/day
Ib/qal
qal/day
Time
NTU
NTU
NTU
NTU
NTU
NTU
NTU
Filter No.
NTU
NTU
Data
24004)400
1
Parameter
Filter aid batch density
Other chemical use
Other chemical density
Finished alkalinity
Finished pH
Finished free chlorine
Giardia Inact target
Chlorine use
Orthophosphate use
0400-0800
2
0800-1200
3
Units
ib/qal
qal/dav
Ib/dav
mg/L
units
mg/L
log
Ib/dav
Ib/day
1200-1600
4
Data
1600-2000
2000-2400
229
-------
Appendix K
Example Process Control Daily Report
231
-------
Water Treatment Plant Process Control Daily Report
28-Feb-98
arameter
ate
low rate
aw turbidity
awpH
aw alkalinity
aw temperature
oagulant daily use
oag. batch density
Filter aid daily use
Units
m/d/y
MGD
NTU
units
mg/L
gal/day
Ib/gal
gal/day
Data
2/28/98
1.00
5.00
7.5
34.0
5.0
13.0
3.36
2.00
Parameter
Fitter aid batch density
Other chemical use
Other chemical density
Finished alkalinity
Finished pH
Finished free chlorine
Giardia Inact. target
Chlorine use
Orthophosphate use
Units
tb/gal
gal/day
Ib/day
mg/L
units
mg/L
log
Ib/day
Ib/day
Data
0.3
0.000
0.0
30.0
7.2
1.0
1.0
12.0
16.0
urbidity Data
Time
2400-0400
0400-0800
0800-1200
1200-1600
1600-2000
2000-240)
Max. Sedimentation 1
NTU
0.55
0.60
0.75
0.80
0.70
0.50
Wax. Sedimentation 2
NTU
0.60
0.70
0.85
0.90
0.80
0.60
Wax. filter 1 turbidity
NTU
0.05
0.04
0.04
0.06
0.06
0.05
Max. filter 2 turbidity
NTU
0.02
0.02
0.03
0.02
0.03
0.04
vlax. filter 3 turbid ty
NTU
0.08
0.07
0.09
0.10
0.11
0.07
Max. filter 4 turbid ty
NTU
0.05
0.04
0.04
0.03
0.03
0.04
:inished turbidity
NTU
0.04
0.04
0.05
0.06
0.06
0.05
ost Backwash Data
Filter No.
iW turbidity spike
NTU
0.20
0.15
0.25
0.18
'urb. 15 min. on-line
NTU
0.07
0.06
0.11
0.07
Calculated Parameters
toaqulant dose
ilter aid dose
Jtlier chemical dose
Chemical cost
mg/L
mg/L
mg/L
$/m gal
5.24
0.060
0.00
47.91
Required CT
mg/L-min
Measured CT
mg/L-min
CT ratio
57.2
103.7
1.8
Filter 1
--O--Filter2
0.16
. 0.14
D0.12
5.0.10
£ 0.08
1 0.06
£ 0.04
0.02
0.00
t—r
li
o°
II
Time
Filter 3 - • O • • Filter 4. J
2400-
0400
0400-
0800
0800- 1200-
1200 1600
Time
1600-
2000
2000-
2400
E3BW spike
E 15 min after BW
0.00
— • — Sed1
• - O
--Sed2
— 0.50
2 0.40
5 0.30
H 0.20
0.10
0.00
2400-
0400
0400-
0800
0800-
1200
1200-
1600
1600-
2000
2000-
2400
232
-------
Appendix L
Example Jar lest Guideline
233
-------
JAR TEST PROCEDURE (page 1)
EST CONDITIONS
Facility
Date
Time I Turbidity Temperature! pH
Alkalinity
I
Water Source
Coagulant
Coagulant Aid
'REPARING STOCK SOLUTIONS
tep 1
Select desired stock solution concentration (see Table 1).
Choose a stock solution concentration that will be practical for transferring chemicals to jars.
Table 1
Stock
Solution
0.01
0.05
0.1
0.2
0.5
1.0
1.5
2.0
Concentration
(mg/L)
100
500
1,000
2,000
5,000
10,000
15,000
20,000
Desired Stock Solution
/O/ \
\ "*/
mg/L dosage per mL
of stock solution
added to 2 liter jar
0.05
0.25
0.5
1
0
2.5
5,0
7.5
10.0
Coagulant
Coag. Aid
itep 2
Determine chemical amount to add to 1 liter flask.
If using dry products, see Table 2. If using liguid products, go to step 3.
Table 2
Stock Solution
0.01
0.05
0.1
0.2
0.5
1.0
1.5
2.0
Cone.
(mg/L)
100
500
1,000
2,000
5,000
10,000
15,000
20,000
Desired Amount
in 1 liter flask (mU
mg of alum added
to 1 liter flask
100
500
1,000
2,000
5,000
10,000
1 5,000
20,000
Coagulant | Coag. Aid
itep 3
Determine liguid chemical amount to add to volumetric flask.
For liquid chemicals, use the eguation below -
mL coagulant =
(stock solution %) x (flask volume, mL) x (8.34 Ib/gal)
100 x (chemical strength, Ib/gal)
Chemical Strength (Ib/gal)1
Stock Solution Volume (mL)
Desired Volume of Chemical
to add to Flask (mL)
Coagulant
Polymer
' Note: Chemical Strength = chemical density x % strength
234
-------
JAR TEST
PROCEDURE (page 2)
JAR SETUP
Set up individual jar doses based on desired range of test.
Determine amount of stock solution by dividing dose by mg/L per ml fsee Table 1).
Coagulant- Jar #
Dose (mg/L)
Stock Solution (ml)
Coagulant Aid- Jar #
Dose (mg/L)
Stock Solution (ml)
Dose (mg/L)
Stock Solution (mL)
1 2
1 2
1 2
3
3
3
456
456
456
TEST PROCEDURE
Stepl
Set rapid mix time equal to rapid mix detention time.
To determine rapid mix time, use the following equation -
Rapid mix time (min) = (rapid mix volume, gal) x
Step 2
Roc time (min) =
(plant flow
Mix Volume (gal)
Plant Flow Rate (gal/day)
Mix Time (sec)
(1 ,440 min/day) x (60 sec/min)
rate, gal/d)
Set total flocculation time equal to total flocculation detention time in plant.
To determine total flocculation time, use the following equation -
(flocculator volume, aal) x (1,440 min/day)
(plant flow rate, gal/d)
Step 3
Step 4
Sample time (min) =
Floe Volume (gal)
Floe Time (min)
Use Figure 1 to determine the jar mixing energy values (rpm) that correspond to the approximate
flocculator mixing energy values (G). Flocculator mixing energy can be esfmated from plant
design information (O&M manual) or can be calculated from the equation described in
Appendix F - B.1 . Flocculation.
Flocculator Stage
Flocculator Mixing (G)
Jar Mixing (rpm)
1st
2nd 3rd
Set sample time based on particle settling velocity. Use the equation below to determine
sample time when using 2 liter gator jars as described in Figure 1 .
(10 cm) x (surface area, ft2) x (1 ,440 min/day) x (7.48 gal/ft3)
(plant flow rate, gal/d) x (30.48 cm/ft)
Sedimentation Surface Area (ft2)
Plant Flow Rate (gal/day)
Sample Time (min)
235
-------
JAR TEST PROCEDURE (page 3)
'EST RESULTS
Record test results in the table below.
iettled Turbidity (NTU)
lettled pH
iltered Turbidity (NTU)
1
2
3
4
5
6
lomments:
toe
rot
too
+OO
J00
IOO
to
to
O-7.ec/n
f f
s 1 t m t t
Impeller Speed (rpm)
z
\ "" I '
too tat
Figure 1. Laboratory G Curve for Flat Paddle in 2 Liter Gator Jar
236
-------
Appendix M
Chemical Feed Guidelines
237
-------
Chemical Feed Guidelines
The following guidelines provide information on
the use of water treatment chemicals for coagula-
tion and particle removal. Typical chemicals used
for these applications include coagulants, floccu-
lants, and filter aids. To use these chemicals
properly, it is necessary to understand how the
specific chemicals function and the type of calcu-
lations that are required to assure accurate feed-
ing. Although these guidelines focus on coagula-
tion and particle removal, the discussion on
determining feed rates and preparing feed solu-
tions applies to other water treatment chemical
applications such as corrosion and taste and odor
control.
Chemicals for Coagulation and Particle
Removal
Coagulation Chemicals
Alum
1. Alum (aluminum sulfate) is one of the most
widely used coagulants in water treatment.
When alum is added to water, insoluble pre-
cipitates such as aluminum hydroxide (AI(OH)3)
are formed.
2. The optimum pH range for alum is generally
about 5 to 8.
3. Alkalinity is required for the alum reaction to
proceed. If insufficient alkalinity is present in
the raw water, the pH will be lowered to the
point where soluble aluminum ion is formed
instead of aluminum hydroxide. Soluble alu-
minum can cause post flocculation to occur in
the plant clearwell and distribution system.
4. As a rule of thumb, about 1 .O mg/L of com-
mercial alum will consume about 0.5 mg/L of
alkalinity. At least 5 to 10 mg/L of alkalinity
should remain after the reaction to maintain
optimum pH.
5. 1 .O mg/L of alkalinity expressed as CaC03 is
equivalent to:
0.66 mg/L 85% quicklime (CaO)
. 0.78 mg/L 95% hydrated lime (Ca(OH)3)
• 0.80 mg/L caustic soda (NaOH)
1.08 mg/L soda ash (Na2C03)
1.52 mg/L sodium bicarbonate (NaHC03)
6. If supplemental alkalinity is used it should be
added before coagulant addition, and the
chemical should be completely dissolved by
the time the coagulant is added.
7. When mixing alum with water to make a feed
solution, maintain the pH below 3.5 to prevent
hydrolysis from occurring which will reduce
the effectiveness of the chemical. A 10 to 20
percent alum solution by weight will maintain
this pH requirement in most applications.
8. Density and solution strength values for com-
mercial alum can be found in Table M-l. A
solution strength of 5.4 Ib/gal can be used for
approximate chemical calculations.
Ferric Chloride
1. The optimum pH range for ferric chloride is 4
to 12.
2. When mixing ferric chloride with water to
make a feed solution, maintain the pH below
2.2.
3. Ferric chloride consumes alkalinity at a rate of
about 0.75 mg/L alkalinity for every 1 mg/L of
ferric chloride.
4. Ferric chloride dosage is typically about half of
the dosage required for alum.
5. Density and solution strength values for com-
mercial ferric chloride vary with the supplier.
A solution strength of 3.4 Ib FeCI3/gallon can
be used for approximate chemical calculations
(i.e., product density of 11.3 Ib/gal and 30
percent FeCI3 by weight).
238
-------
Table M-l. Densities and Weight Equivalents of Commercial Alum Solutions'
Specific
Gravity
1.0069
1.0140
1.0211
1.0284
1.0357
1.0432
1.0507
1.0584
1.0662
1.0741
1.0821
1 .OOO3
1.0985
1.1069
/ 1.1154
1.1240
1.1328
1.1417
1.1508
1.1600
1.1694
1.1789
1.1885
1.1983
1.2083
1.2185
1.2288
1.2393
1 .2600
1.2609
1.2719
1.2832
1.2946
1.3063
1.3182
1.3303
1.3426
1.35R1
l.MB__.
Density
Ib/gal
8.40
8.46
8.52
8.58
8.64
8.70
8.76
8.83
8.89
8.96
9.02
o.oo
9.16
9.23
9.30 1
9.37
9.45
9.52
9.60
9.67
9.57
9.83
9.91 1
9.99
10.08
10.16
10.25
10.34
10.43
10.52
10.61
10.70
10.80
% AI203
0.19
0.39
0.59
0.80
1.01
1.22
1.43
1.64
1.85
2.07
2.28
2.50
2.72
2.93
3.15
3.38
3.60
3.82
4.04
4.27
4.50
4.73
4.96
5.19
5.43
5.67
5.91
6.16
6.42
6.67
6.91
7.16
7.40
10.89 7.66
10.99
11.09
11.20
11.30
11.41
7.92
8.19
8.46
8.74
9.01
Equivalent %
Dry Alum2
1.12
2.29
3.47
4.71
5.94
7.18
8.41
9.65
10.88
12.18
13.41
14.71
16.00
17.24
18.53
19.88
21.18
22.47
23.76
25.12
26.47
27.82
29.18
30.53
31.94
33.35
34.76
36.24
37.76
Strength
Ib alum/gallon
0.09
0.19
0.30
0.40
0.51
0.62
0.74
0.85
0.97
1.09
1.21
1.34
1.47
1.59
1.72
1.86
2.00
2.14
2.28
2.43
2.58
2.74
2.89
3.05
3.22
3.39
3.56
3.74
3.93
39.24 4.12
40.65
42.12
43.53
45.06
46.59
48.18
49.76
51.41
53.00
4.31
4.51
4.71
4.91
5.12
5.34
5.57
5.81
6.05
Strength
g alum/liter
11.277
23.221
35.432
48.438
61.521
74.902
88.364
102.136
116.003
130.825
145.110
160.368
175.760
190.830
206.684
223.451
239.927
256.540
273.430
291.392
309.540
327.970
346.804
365.841
385.931
406.370
427.131
449.122
472.000
494.777
517.027
540.484
563.539
588.619
614.149
640.938
668.078
696.657
724.987
'From Allied Chemical Company "Alum Handbook", modified by adding gm/L dry alum column.
217% AI203 in Dry Alum + 0.03% Free AI203.
239
-------
Polyaluminum Chloride (1 )
Flocculation Chemicals
1. Polyaluminum chloride (PACI) products are less
sensitive to pH and can generally be used over
the entire pH range generally found in drinking
water treatment (i.e., 4.5 to 9.5).
2. Alum and PACI products are not compatible; a
change from feeding alum to PACI requires a
complete cleaning of the chemical storage
tanks and feed equipment.
3. The basicity of the product determines its
most appropriate application:
Low basicity PACIs (below 20 percent):
Applicable for waters high in color and
total organic carbon (TOO.
Medium basicity PACIs (40 to 50 per-
cent): Applicable for cold water, low tur-
bidity, and slightly variable raw water
quality.
High basicity PACIs (above 70 percent):
Applicable for waters with highly variable
quality, as a water softening coagulant,
for direct filtration, and some waters with
high color and TOC.
4. Check specific manufacturer's product infor-
mation for density and strength values.
Polymers (Coagulation)
1. Polymer can be added as either the primary
coagulant or as a coagulant aid to partially
replace a primary coagulant (e.g., alum).
2. Polymers used for coagulation are typically low
molecular weight and positively charged (cati-
onic).
3. The dosage for polymers used for coagulation
is dependent on raw water quality.
4. Product density and solution strength informa-
tion can be obtained from the individual poly-
mer manufacturers.
1. Polymers used as flocculants generally have a
high molecular weight and have a charge that
is positive, negative (anionic), or neutral (non-
ionic).
2. The purpose of a flocculant is to bridge and
enmesh the neutralized particles into larger floe
particles, and they are generally fed at a dos-
age of less than 1 mg/L.
3. Flocculants should be fed at a point of gentle
mixing (e.g., diffuser pipe across a flocculation
basin) to prevent breaking apart the long-
chained organic molecules.
4. Product density and solution strength informa-
tion can be obtained from the individual poly-
mer manufacturers.
Filter Aid Chemicals
1. Polymers used as filter aids are similar to floc-
culants in both structure and function.
2. Filter aid polymers are typically fed at dosages
less than 0.1 mg/L; otherwise, when fed in
excess concentrations they can contribute to
filter head loss and short filter run times.
3. Filter aid polymers are fed at a point of gentle
mixing (e.g., filter influent trough).
4. Product density and solution strength informa-
tion can be obtained from the individual poly-
mer manufacturers.
Feeding Chemicals in the Plant
Step 1. Determining the Required Chemical
Dosage
1. The appropriate chemical dosage for coagu-
lants is typically determined by lab or pilot
scale testing (e.g., jar testing, pilot plant), on-
line monitoring (e.g., streaming current meter,
particle counter), and historical experience. A
guideline on performing jar testing is include in
Appendix L.
240
-------
2. Flocculants are typically fed at concentrations
less than 1 mg/L. Jar testing can be used to
estimate the optimum dosage.
3. The typical dosage for filter aid polymers is
less than 0.1 mg/L. Jar testing, including fil-
tering the samples, is typically not effective for
determining an optimum dose. The polymer
manufacturers can provide guidelines on use
of their products as filter aids.
Step 2. Determining the Chemical Feed Rate
1. Once the chemical dosage is determined, the
feed rate can be calculated by the equation
below:
Feed Rate (Ib/day) = Flow Rate (MGD) x
Chemical Dose (mg/L) x 8.34 Ib/gal
Step 3. Determining the Chemical Feeder
Setting
1. Once the chemical feed rate is known, this
value must be translated into a chemical feeder
setting. The approach for determining the set-
ting depends on whether the chemical is in a
dry or liquid form.
2. For dry chemicals, a calibration curve should
be developed for all feeders that are used in
the plant. A typical calibration curve is shown
in Figure M-l, The points on the curve are
determined by operating the feeder at a full
operating range of settings and collecting a
sample of the chemical over a timed period for
each setting. Once the sample weight is
determined by a balance, the feed rate can be
determined for that set point. For example,
the feed rate for the 100 setting was deter-
mined by collecting a feeder output sample
over a 2-minute period. The sample weight
was 5.8 Ib. The associated feed rate can then
be converted into an equivalent hourly feed
rate as follows:
Feed Rate = 5-^-x60min
2min
hr
174 Ib
hr
a plant. An approach similar to dry feeder
calibration is followed; however, a volumetric
cylinder is typically used to collect the sample.
For example, 50 mL of liquid chemical col-
lected over 2 minutes would equate to a feed
rate of 25 mL/min. A graph similar to
Figure M-l can be developed showing pump
setting (e.g., % speed) versus feed rate in
mL/min.
4. For liquid chemicals, an additional step is nec-
essary to convert the required weight-based
feed rate to a volume-based pumping rate.
The following equation can be used to deter-
mined the pumping rate:
PumpRate(ml/&ffi) = *-x *£
3,785 mL
6'ay (Csflb 1,440miri gal
FR = Feed Rate (Ib/day)
Cs = Chemical Strength (Ib/gal)
Preparation of Feed Solutions
Liquid solutions of both dry and liquid chemicals
are frequently prepared in a plant to prepare the
chemical for feeding (e.g., activating polymer) and
to allow the feeding of the chemical in an efficient
manner. Two examples are presented below to
describe approaches for preparing chemical solu-
tions from dry and liquid chemicals.
Preparation of an Alum Feed Solution
1. Determine the desired percent solution for
feeding the alum. As described under the pre-
vious alum discussion, a percent solution of
10 to 20 percent is typically used. In this
example, assume a 15 percent solution.
2. Based on the volume of alum solution to be
prepared, determine the weight of alum to add
to the solution tank. For an alum solution vol-
ume of 500 gallons, determine the alum
weight as follows:
Alum Weight = 500 gal x — xO.15 = 625 Ib
gal
3. For liquid chemicals, a calibration curve should
also be developed for all liquid feeders used in
241
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Figure M-l. Example dry chemical feeder calibration chart.
Setting
0
100
200
300
400
500
Sample Wt.
(Ib)
0
5.8
5.1
7.3
4.8
5.7
Time
(minutes)
0
2.0
1.0
1.0
0.5
0.5
Feed Rate
(Ib/hr)
0
174
306
438
576
684
700
600
500
•c-
1 400
| 300
200
100
50 100 150 200 250 300 350 400 450 500
Feeder Setting
3. Determine the alum strength (A,) for use in
calculating feed rates. The alum strength for
the example above is calculated as follows:
Alum Strength (A,) =
625 Ib 1.25lb
500 gal gal
Preparation of a Polymer Feed Solution
1. Polymer manufacturers provide guidelines on
preparation of their products, including
whether the product is fed neat (i.e., undi-
luted) or in a diluted form. Diluted polymers
are typically mixed at 2% by weight or less;
otherwise, they become difficult to mix effec-
tively. For this example, assume a 1% solu-
tion is to be prepared.
2. Based on the volume of solution to be pre-
pared, determine the weight of polymer to add
to the solution tank. For a solution volume of
200 gallons, determine the polymer weight as
follows:
Polymer Weight = 200 gal x 8'34 lb x 0.01 = 16.7 Ib
3. It is frequently easier to measure polymer
volumetrically rather than by weight, so the
weight of polymer can be converted to an
equivalent volume by obtaining the product
density from the manufacturer. For example,
if the polymer density is 9.5 Ib/gal, the volume
is calculated as follows:
Polymer Volume = 16.7 Ib x
gal
9.5 lb
= 1.76 gal
242
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4. Determine the polymer strength (Ps) for use in
calculating feed rates. The polymer strength
for the example above is calculated as follows:
.u/r, N 16.7lb 0.0835 Ib
Polymer Strength (Ps) = __, _-
Ref ecences
1. Lind, Chris. 1996. "Top 10 Questions about
Alum and PACI." Opflow, 22(8):7. AWWA,
Denver, CO.
243
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Appendix N
Conversion Chart
245
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Conversion Chart
English Unit
acre
acre-ft
cfs
cu ft
cuft
°F
ft
ft/sec
gal
gpm
gpm
gpd/sq ft
gpm/sq ft
inch
Ib
Ib
MGD
psi
sqft
Multiplier
0.405
1,233.5
1.7
0.0283
28.32
5/9 x ("F-32)
0.3048
30.48
3.785
0.0631
8.021
0.0408
40.7
2.54
0.454
454
3,785
0.070
0.0929
SI Unit
ha
cu m
cu m/min
cu m
I
°C
m
cm/sec
I
liter/sec
cu ft/hr
cu m/day/sq m
l/min/sq m
cm
kg
g
cu m/day
kg/sq cm
sq m
246
>U.S GOVERNMENT PRINTING OFFICE: 1998 653-662
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