UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
REGION III - PHILADELPHIA, PENNSYLVANIA
SLUDGE MANAGEMENT STUDY
BLUE PLAINS WASTEWATER TREATMENT PLANT
WASHINGTON, D.C.
DRAFT
ENVIRONMENTAL IMPACT STATEMENT
MARCH 1989
• .il:^r \or
GANNETT FLEMING ENVIRONMENTAL ENGINEERS, INC.
HARRISBURG, PENNSYLVANIA
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION III
841 Chestnut Building
Philadelphia, Pennsylvania 19107
LETTER OF TRANSMITTAL
TO: ALL INTERESTED CITIZENS, AGENCIES AND PUBLIC INTEREST GROUPS:
This draft Environmental Impact Statement (EIS) represents the cul-
mination of a lengthy and detailed evaluation of disposal alternatives
for sewage sludge generated at the District of Columbia's Blue Plains
waste water treatment facility. Current sludge production is over 250
dry tons per day and is expected to increase to 410 dry tons per day
within the next 20 years, based upon original figures supplied by D.C..
The draft EIS studies the options for long-term disposal of approximately
one-half of the sludge generated at Blue Plains. For the remaining
sludge production, the District and other jurisdictions involved in the
operation of Blue Plains have agreed to composting, both on-site and in
suburban Maryland. In 1984, EPA issued a Finding of No Significant Im-
pact (FNSI) for the composting operation, pursuant to the requirements
of the National Environmental Policy Act (NEPA) and regulations promul-
gated by the President's Council on Environmental Quality (CEQ). At the
same time, the District proposed incineration of sludge as the other
long-term solution to be operated in tandem with composting. Over the
past five years land application has been utilized in addition to compost-
ing. However, the District and user jurisdictions view land application
as a short-term solution to sludge management.
EIS's are required for projects that involve "major Federal actions"
such as expenditure of Federal funds. Total capital costs for incinera-
tion are estimated at $96 to $113 million, depending upon the number of
units and design configuration. The District has included incineration
on the Construction Grants Priority List for proposed funding by EPA.
Because of environmental concerns with incineration and the large expen-
diture of public funds, EPA initiated the EIS process under NEPA and CEQ
regulations. As stated in CEQ Regulations, "The NEPA process is intended
to help public officials make decisions that are based on understanding
of environmental consequences, and take actions that protect, restore, and
enhance the environment." A thorough comparison of all viable alternatives
is required by the NEPA process. Public participation is part of the
NEPA process and is critical to making significant policy decisions.
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It is from this perspective that EPA has approached the evaluation
of the various alternatives for sludge disposal. Composting, pelletizing,
ocean disposal, and land application were evaluated in addition to incin-
eration. These were narrowed down to three primary alternatives — incin-
eration, composting, and land application. All were evaluated in depth.
It is important to note that none of these primary alternatives, if prop-
erly operated, would result in violations of existing environmental regu-
lations and standards. Given the probable regulatory compliance of the
alternatives, other factors were then considered. Most notably technical
feasibility, cost effectiveness, environmental acceptability, and imple-
mentability were considered. These issues are addressed in the body of
the report and refined in Appendix I, which was prepared in response to
concerns raised during EPA's internal review of the preliminary document.
In regard to technical feasibility and costs, early analysis revealed
that additional composting at Blue Plains could not be recommended because
of constraints imposed by lack of space at the facility. This left incin-
eration and land application as the primary alternatives for final con-
sideration. From a cost effectiveness viewpoint, land application and
incineration'are comparable based on standard engineering estimating tech-
niques.
From an environmental.acceptability perspective, EPA policy for the
funding of projects requires that recycling and reuse are to be considered
options of choice wherever economically feasible. Given the policy and
comparability of costs, land application is considered more environmentally
desirable. EPA's reasons for preferring land application relate to the
relatively low levels of chemical impurities in Blue Plains sludge, making
the sludge highly desirable as a soil conditioner and agricultural fertil-
izer. Using incineration, this potentially valuable resource would be
los.t. In addition, the application of sludge reduces the adverse effects
of soil erosion, nutrient runoff, and ground water contamination when com-
pared to chemical fertilizers that would otherwise be used.
The District currently land applies an average of 140 dry tons per day,
or nearly three-fifths of its production. The program has been successfully
implemented over the past four to five years. Under EPA's preferred alter-
native, an additional 60 tons per day would be land applied, bringing the
total to an average of 200 tons per day. Current composting accounts for
about 100 tons; an additional 110 tons was part of the 1984 FNSI and will
complement the tonnage disposal picture. Numerous municipalities employ
land-based technology for sludge management with proven reliability. This
includes larger municipalities which have higher levels of chemical impur-
ities in their sludges than the Blue Plains material. Although concern has
been raised about the availability of suitable land, EPA's evaluation indi-
cates that there is sufficient acreage for Blue Plain's sludge in Maryland
and Virginia. Land to accommodate Blue Plains sludge is available for at
least the next 20 years.
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Since 1984, the District of Columbia and the user jurisdictions have
been on a course of developing independence in managing Blue Plains sludge.
EPA acknowledges their desire to have total management control over sludge
disposal and that construction of incinerators would maximize that control.
The District and the user jurisdictions are particularly concerned over im-
plementing and sustaining a viable, long-term land application solution.
In addition, the District is concerned that the public acceptance of land
application of sludge will diminish over time, leaving them with no ade-
quate disposal system in place.
Land application requires a highly developed infrastructure of con-
tract management and inter-governmental coordination and cooperation.
Although incineration requires sophisticated technical management atten-
tion, it does not need the degree of inter-governmental coordination and
cooperation required by land application. Overall, EPA recognizes that
land application would impose more stringent sludge management require-
ments than incineration.
A primary purpose of this draft EIS is to encourage public involve-
ment in this'very important issue. Public involvement is essential to
arriving at an informed and balanced public policy decision. This deci-
sion is of extreme significance to the residents of the District of
Columbia, Maryland and Virginia. If land application is the selected al-
ternative, implementation will require continued cooperation and involve-
ment between the District and neighboring jurisdictions.
EPA is particularly interested in receiving comments on the imple-
mentability of the land application alternative. EPA will conduct a pub-
lic meeting on this EIS, open to all interested parties. Written comments
are also encouraged. All comments will be appreciated and considered in
preparation of the final Environmental Impact Statement.
t>
cowsk:
Stanley L. Laskowski
Acting Regional Administrator
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ACKNOWLEDGEMENTS
We wish to acknowledge the assistance of several persons and organiza-
tions associated with the Blue Plains Sludge Management Study:
Mr. Kenneth G. Laden, Chief, Environmental Policy Division, Department
of Public Works, Washington, D.C., who provided necessary regulatory
documents and helpful comments.
Dr. Timothy G. Shea, Project Manager, and D. A. Toothman, Engineering-
Science, Inc., Fairfax, VA and their staff who prepared numerous reports on
the Blue Plains facility and the proposed incineration system and provided
a review of sludge management experience at Blue Plains from 1973 to 1983.
Those individuals from the Washington Suburban Sanitary Commission, the
Council of Governments and the Blue Plains user counties of Montgomery,
Fairfax and Prince George's who provided comments and suggestions.
The District's contractors who provided data and support documents for
information presented in the land application and composting sections of the
EIS.
And the staff at the Blue Plains plant who answered numerous questions
regarding the present operations at the facility.
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TABLE OF CONTENTS
Page
Table of Contents i
List of Tables v
List of Figures viii
List of Plates ix
Executive Summary ES-1
Chapter 1. Background and History of the Project 1-1
1.1 Background and Purpose of the EIS 1-1
1.2 History 1-3
1.2.1 Wastewater Treatment 1-5
1.2.2 Wastewater Solids Management 1-6
1.3 Existing Facilities 1-13
1.3.1 Wastewater Treatment 1-13
1.3.2 Wastewater Solids Treatment 1-15
1.3.2.1 Blue Plains 1-15
1.3.2.2 Off-site Processing 1-18
1.4 Expansion and Upgrading Plans 1-21
Chapter 2. Description of Sludge Management Methods 2-1
2.1 Applicable Methods 2-1
2.2 No Action 2-4
2.3 Incineration With Ash Landfilling 2-7
2.3.1 Multiple Hearth Furnace (MHF) 2-7
2.3.2 Fluidized Bed Furnace (FBF) 2-10
2.4 Land Application 2-19
2.5 Composting 2-27
2.6 Drying and Product Use 2-36
2.7 Landfilling . 2-41
2.8 Ocean Disposal 2-46
Chapter 3. Cost, Operational, and Implementation Comparison 3-1
of Sludge Management Methods
3.1 Introduction 3-1
3.2 Cost Comparison 3-1
3.3 Operability Evaluation 3-5
3.3.1 Reliability 3-5
3.3.2 Flexibility 3-7
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TABLE OF CONTENTS (Cont'd.)
3.3.3 Maintainability 3-7
3.3.4 Overall Operability 3-8
3.4 Implementability Evaluation 3-9
3.4.1 Public Acceptability 3-9
3.4.2 Management Concerns 3-11
3.4.3 Overall Implementability 3-11
3.5 Regulatory Framework 3-13
3.5.1 Incineration With Ash Disposal 3-13
3.5.2 Land Application 3-13
3.5.3 Composting 3-14
3.5.4 Drying and Product Use 3-14
3.5.5 Landfilling 3-14
3.5.6 Ocean Disposal 3-14
3.6 Summary Comparison 3-15
Chapter 4. Affected Environment of the Methods and 4-1
Mitigative Measures
4.1 Environmental Impacts of the Methods 4-1
4.2 No Action 4-2
4.2.1 Land Application 4-3
4.2.2 Composting 4-4
4.2.3 Man-Made Environmental Impacts 4-6
4.3 Incineration 4-8
4.3.1 Air Quality Impacts 4-8
4.3.1.1 Regulations 4-8
4.3.1.2 Emissions - Existing Sources 4-9
4.3.1.3 Emission Factors 4-10
4.3.1.4 Emission Rates 4-13
4.3.1.5 Dispersion Modeling Analysis 4-17
4.3.1.6 Air Quality Impact Areas 4-18
4.3.1.7 Existing Ambient Air Quality- 4-18
PSD Increments
4.3.1.8 Projected Ambient Air Quality 4-20
4.3.1.9 Health Risk Assessment 4-23
4.3.2 Ash Disposal 4-25
4.3.3 Man-Made Environmental Impacts 4-27
4.3.4 Air Pollution Control Systems 4-28
4.4 Land Application 4-33
4.4.1 Natural Environmental Impacts 4-33
4.4.1.1 Nutrients 4-33
4.4.1.2 Heavy Metal 4-38
4.4.1.3 Pathogens 4-42
4.4.2 Impacts on the Man-Made Environment 4-45
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TABLE OF CONTENTS (Cont'd.)
4.5 In-Vessel Composting 4-46
4.5.1 Natural Environmental Impacts 4-46
4.5.2 Man-Made Environmental Impacts 4-51
4.5.3 Health Risk Assessment 4-53
4.6 Drying and Product Use 4-55
4.6.1 Natural Environmental Impacts 4-55
4.6.1.1 Air Quality 4-55
4.6.1.2 Soil and Surface Waters 4-56
4.6.2 Man-Made Environmental Impacts 4-59
4.7 Landfilling 4-62
4.7.1 Natural Environmental Impacts 4-62
4.7.2 Man-Made Environmental Impacts 4-66
4.8 Ocean Disposal 4-68
4.8.1 Natural Environmental Impacts 4-68
4.8.2 Man-Made Environmental Impacts 4-72
4.9 Adverse Impacts of the Alternatives and 4-76
Mitigative Measures
4.9.1 Sludge Management 4-76
4.9.2 Sludge Transport 4-80
4.9.3 Sludge Disposal 4-80
Chapter 5. Screening of Sludge Management Methods 5-1
5.1 Introduction 5-1
5.2 Basis for Screening 5-1
5.3 Screening 5-5
5.3.1 Landfilling 5-5
5.3.2 Ocean Disposal 5-5
5.3.3 Composting 5-5
5.3.4 Drying and Product Use 5-5
5.3.5 Incineration and Ash Landfilling 5-6
5.3.6 Land Application 5-6
Chapter 6. Development and Evaluation of Final Alternative 6-1
6.1 Introduction 6-1
6.2 Overall Sludge Management 6-1
6.3 Development of Alternatives 6-3
6.3.1 Methodology 6-3
6.3.2 No Action Alternative 6-3
6.3.3 Incineration (District Concept) 6-3
6.3.4 Land Application 6-7
6.3.5 Combined Incineration/Land Application 6-7
6.4 Evaluation of the Alternatives 6-11
6.4.1 Costs 6-11
111
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TABLE OF CONTENTS (Cont'd.)
6.4.2 Environmental Impacts
6.4.3 Implementation Characteristics
6.5 Summary
Chapter 7. Preferred Sludge Management Alternative at Blue Plains 7-1
7.1 Introduction
7.2 Sludge Management Alternatives
7.2.1 Management Concerns
7.2.2 Environmental Concerns
7.2.3 Economic Concerns
7.3 Preferred Alternative
7.3.1 Management Benefits
7.3.2 Environmental Benefits
7.4 Conclusions
REFERENCES
7-1
7-2
7-2
7-4
7-6
7-7
7-8
7-9
7-10
R-l
Appendix A. Local, State and Federal Regulations A-l
Appendix B. Prevention of Significant Deterioration (PSD) B-l
Categories, Major Source Definition
Appendix C. List of Priority Pollutants C-l
Appendix D. Survey: Facilities Composting Municipal D-l
Sludge in the United States
Appendix E. Survey: Facilities Incinerating Municipal E-l
Sludge in the United States
Appendix F. Summary and Conclusions: Incineration and F-l
Composting Technology Inventory, EcolSciences,
Inc., August, 1986
Appendix G. Solids Management Alternatives Cost Analysis Values G-l
Appendix H. Design Year Sludge Quantities Subject to EIS H-l
Appendix I. Additional Considerations Regarding Land 1-1
Application of Sewage Sludge in Virginia and
Maryland
IV
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List of Tables
Table Number Title Page
ES.1 Comparison of Alternatives ES-9
1.1 A Chronology of Events at the 1-25,26,27
Blue Plains Plant
2.1 Sludge Management Methods 2-2
2.2 Blended Sludge Ash Leachate Character- 2-16
ization
2.3 Sludge Characterization Summary 2-17
2.4 Sludge Stream Quality Summary 2-22
2.5 Summary of Contract Land Application 2-23
Facilities
2.6 Individual Sludge Stream Character- 2-24
ization Summary
2.7 Land Application Sludge Value 2-26
2.8 Sludge and Site Conditions 2-43
2.9 Range of Constituent Concentrations 2-45
in Leachate from Sludge Landfills
2.10 Typical Barge Capacities and Speed 2-47
3.1 Summary of Solids Management Methods 3-2
Present Worth Analysis
3.2 Summary of Annual Equivalent Cost 3-4
Per Dry Ton
3.3 Summary of Operability Evaluation 3-6
3.4 Summary of Implementability Character- 3-10
istics
3.5 Summary of Technical Evaluations and 3-17
Regulatory Framework
4.1 Existing and District Proposed Blue 4-2
Plains Sludge Disposal Methods
4.2 Air Emissions Summary 4-11
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List of Tables (Cont'd.)
Table Number Title Page
4.3 Summary of VOCs Detected in Blue Plains 4-12
Influent and Effluent Samples
4.4 Emission Factors 4-14
4.5 Estimated Emissions for the Fluidized 4-15
Bed Furnace System Proposed for Blue
Plains
4.6 Predicted Average Concentrations 4-19
4.7 Projected Ambient Air Quality 4-21
4.8 PSD Increment Consumption 4-22
4.9 Health Risk Assessment Results 4-24
4.10 Results of Analysis for Pollutants 4-26
with Threshold Health Effects
4.11 Estimated Removal Efficiencies for 4-30
Pollution Devices Proposed for Blue
Plains Incinerators
4.12 Individual Sludge Stream Character!- 4-34
zation Summary - January-May 1986
Data Period
4.13 Nitrogen Requirements for Selected 4-37
Crop Yields
4.14 Maximum Metal Accumulations for 4-38
Sludge Amended Soils
4.15 Pathogens Found in Sludges and 4-43
Resultant Diseases
4.16 Comparison of Sludge and Compost 4-47
Constituents
4.17 Analysis of Condensate, Leachate 4-50
and Runoff from a Composting
Operation
4.18 Average Major Chemical Components 4-58
of Sludge
4.19 Leachate Quality from Sludge - Only 4-64
Landfill
VI
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List of Tables (Cont'd.)
Table Number Title Page
4.20 Release in Seawater of Heavy Metals 4-69
from Sludge
4.21 Summary of Potential Impacts and 4-77,78,79
Mitigative Measures
5.1 Comparison of Alternatives 5-2
6.1 Summary of Solids Management 6-12
Alternatives Present Worth Cost
Analysis
6.2 Summary of Environmental Impact 6-13
Potential
6.3 Flexibility Characteristics 6-16
6.4 Public Acceptability Characteristics 6-17
6.5 Management Characteristics 6-18
vii
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List of Figures
Figure Number Title Paee
O " •" II ••' — I ^^fr^
1.1 Blue Plains Waste Water Treatment 1-14
Plant
1.2 Blue Plains Waste Water Treatment 1-16
Plant - Existing Wastewater
Solids Process Flow Diagram
1.3 Facility Layout - Site II Montgomery 1-19
County Composting Facility
1.4 Responsibilities of Sludge Manage- 1-23
ment as Defined in the Intermunicipal
Agreement of 1985
1.5 Proposed Long-Term Wastewater 1-28
Solids Management Plan for Blue
Plains Wastewater Treatment Plant
2.1 Blue Plains Wastewater Treatment 2-3
Plant Sludge Management Methods
2.2 Existing Wastewater Sludge 2-5
Management at Blue Plains
Wastewater Treatment Plant
2.3 Cross Section of a Typical 2-8
Multiple Hearth Incinerator
2.4 Plant Flow Diagram for Multiple 2-9
Hearth Furnaces
2.5 Cross Section of a Fluid Bed 2-11
Furnace
2.6 Flow Diagram for Fluid Bed 2-13
Incineration System
2.7 Comparison of Composting Processes 2-28
by Method
2.8 Schematic of the Beltsville 2-30
Extended Aerated Static Pile
Composting System
2.9 Schematic Diagram of Various 2-31
Mechanical In-Vessel Composting
Systems
viii
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List of Figures (Cont'd.)
Figure Number
2.10
2.11
2.12
4.1
4.2
6.1
6.2
6.3
6.4
6.5
6.6
6.7
Title
Proposed Layout of Facilities in
the Denitrification Area
Schematic for a Rotary Dryer
Wastewater Solids Deposition
at Sea
Sites Visually Impacted by
Incinerator Stacks
Comparison of Compost Metal
Concentrations
Total Sludge Distribution Over
Planning Period
No Action Alternative Average
Sludge Distribution Over Planning
Period
Four Unit Incineration at
Average Loading Conditions
Four Unit Incineration at Peak
Loading Conditions
Land Application at Average
and Peak Loading Conditions
Combined Incineration/Land
Application at Average Loading
Conditions
Combined Incineration/Land
Application at Peak Loading
Conditions
Page
2-33
2-37
2-49
4-29
4-48
6-2
6-4
6-5
6-6
6-8
6-9
6-10
List of Plates
Plate Number
1.1
Title
District and Suburban Area
Tributary to D.C. Sewer System
Page
1-4
IX
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EXECUTIVE SUMMARY
SHORT SUMMARY
The Blue Plains Wastewater Treatment Plant is a regional facility that
receives wastewater from much of the Washington Metropolitan area. As the
result of a major planning effort by the District of Columbia, recommenda-
tions were made that one portion of the wastewater sludge from the Blue
Plains facility be composted and that a second portion be incinerated.
In August 1984, the U.S. Environmental Protection Agency (EPA) issued a
Finding of No Significant Impact (FONSI) on the sludge composting portion of
the plan, but decided that an Environmental Impact Statement (EIS) would be
required to further evaluate the sludge incineration portion of the plan. A
Notice of Intent to prepare this EIS was also issued in August 1984.
In September 1985, the District of Columbia, the Washington Suburban
Sanitary Commission (WSSC) and the user Counties signed an Intermunicipal
Agreement (IMA) fully endorsing the use of both composting and incineration.
However, implementation of the incineration portion of the plan was held in
abeyance subject to a favorable outcome from the EIS.
After extensive study, the EIS has been completed. Because the FONSI
already approved composting as the method for managing one portion of the
Blue Plains sludge, the EIS addresses only the portion considered for
incineration. The seven alternatives evaluated were (1) no action, (2)
incineration with ash landfilling, (3) land application of dewatered sludge,
(4) in-vessel composting and product use, (5) heat drying and product use,
(6) landfilling dewatered sludge, and (7) ocean disposal.
Land application of dewatered sludge is the alternative preferred by
EPA. Compared with incineration, it maximizes resource reuse and minimizes
energy consumption; it is less operationally complex; permitted farmland is
available; has less environmental impacts; it keeps the District's long-term
options open, and is economically competitive. Furthermore, land application
represents a continuation of a current practice that has been successfully
used at Blue Plains for many years.
ES-1
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DETAILED SUMMARY
INTRODUCTION
The Blue Plains Wastewater Treatment Plant receives wastewater from much
of the Washington Metropolitan area. Because of the size of the plant and
volume of sludge generated (approximately 2,000 wet tons per day or 400 dry
tons per day based upon 20 percent solids) sludge handling and disposal have
been a constant concern. In July 1984, the District of Columbia proposed a
long-term plan based upon concurrent use 'of two disposal methodologies:
(1) Composting:
o Use of the Montgomery County Composting Facility (MCCF Site
II) in suburban Maryland.
o Use of a new mechanical composting facility to be constructed
at the Blue Plains site.
(2) Incineration:
o Use of new sludge incinerators to be constructed at the Blue
Plains site.
In August 1984, the U.S. Environmental Protection Agency (EPA) issued a
Finding of No Significant Impact (FONSI) on the composting portion of the
plan, but decided that an Environmental Impact Statement (EIS) would be
required to further evaluate the incineration portion of the plan. A Notice
of Intent to prepare this EIS was also issued in August 1984.
The FONSI assured the District that on-site composting of dewatered
sludge would remain a major long-term component of the sludge management
plan. Management and environmental problems associated with the existing
aerated static pile composting operations would be reduced with the intro-
duction of in-vessel composting. Composting would be performed in an
enclosed building and the process air would be treated before it is exhausted
to the atmosphere. Under the District's proposal, approximately one-third of
the sludge would be composted.
ES-2
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In September 1985, the District of Columbia, the Washington Suburban
Sanitary Commission (WSSC) and the user Counties signed an Intermunicipal
Agreement (IMA) fully endorsing the composting and incineration methods.
However, implementation of the incineration portion of the plan was held in
abeyance pending the issuance of a favorable EIS. The Intermunicipal
Agreement assumes in-vessel composting of sludge at Blue Plains; composting
of sludge at MCCF - Site II in Montgomery County, MD; and incineration of
sludge at Blue Plains.
Only that quantity of sludge proposed for incineration (200 DTPD as
established for the EIS) at Blue Plains was evaluated during preparation of
this EIS. The alternatives to incineration have been evaluated in terms of
their ability to handle and dispose of only that quantity; not the entire
amount generated at Blue Plains, and in particular not the portion already
approved for composting under the FONSI.
The District of Columbia has issued a series of background and prelimi-
nary engineering reports for the proposed sludge incineration plan. These
reports address: concept, cost, and engineering of multiple hearth and
fluidized bed incineration systems; sludge sampling and characterization; air
emission inventory at the Blue Plains facility; air pollutant emission
factors; and, projected air quality impacts using EPA-approved air dispersion
models. Information from these reports was used extensively during the
preparation of this EIS.
Sludge incineration and six other alternatives have been evaluated;
giving consideration to regulatory constraints, engineering, environmental
impacts, economics and mitigative measures. All alternatives were evaluated
for a 20-year planning horizon. Potential air emissions from the proposed
fluidized bed incinerators were also given considerable scrutiny.
ES-3
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EXISTING SLUDGE MANAGEMENT CONCERNS
The Blue Plains Wastewater Treatment facility has a design capacity of
309 million gallons a day and received flows averaging 287 mgd in 1986. The
continuing growth of the region around metropolitan Washington and a regu-
latory trend toward improved treatment of wastewater has forced the District
to evaluate several sludge disposal alternatives. Land application has been
used with some success over the years, but the District and the user juris-
dictions have encountered varying levels of public opposition to this sludge
disposal method.
The District's experience with the aerated static pile method of com-
posting has had only limited success. The compost facility at Blue Plains
has historically experienced moisture problems that have prevented the
District from producing a marketable compost. However, the District is
currently attempting to resolve this problem. In contrast, Montgomery County
has experienced success in composting 40 DTPD of dewatered sludge, but they
have encountered local opposition to the compost facility because of its
suburban location. Furthermore, odor control facilities are being installed
at MCCF.
Several interim attempts at alternative disposal technologies by the
District have culminated the utilization of in land application of sludge on
permitted points in Maryland and Virginia. The land application program has
experienced more longevity than other alternative methods. Although some
public relations problems have been experienced, the land application program
has been generally successful.
It is difficult to predict the level of public opposition that would
result from an incineration system at Blue Plains. At nearby sludge inciner-
ating facilities that have been operating for some time, there has generally
not been overwhelming opposition; however, an incineration system constructed
several years ago at the WSSC Piscataway treatment facility has never been
operated because of public opposition.
ES-4
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DESCRIPTION OF POTENTIAL SLUDGE MANAGEMENT ALTERNATIVES
There are several sludge disposal technologies available to the
District. These include: (1) no action; (2) incineration with ash landfill-
ing; (3) land application of dewatered sludge; (4) in-vessel composting; (5)
heat drying and product use; (6) landfilling dewatered sludge; and (7) ocean
disposal.
No Action - Composting and Land Application
The no-action alternative presumes a continuation of the current sludge
handling and disposal methods for the EIS sludge. All sludges not subjected
to the FONSI (composting) or the MCCF (composting) would be dewatered and
land applied to the limit of the ability of existing facilities. While land
application has been successfully used for many years, the District has
expressed concerns about its long-term viability because of a fear that
disposal sites will become increasingly limited and that a sharp escalation
in contract prices will also occur.
Incineration and Ash Landfilling
The District desires to construct six fluidized bed furnaces to process
the equivalent of 200 DTPD of sludge. The incineration proposal includes
final ash disposal at the Lorton Landfill. In preparing the EIS, both
multiple hearth and fluidized bed furnaces have been considered. In
addition, a scaled down incineration alternative using fewer fluidized bed
furnaces has been considered. Clearance from the Federal Aviation Admini-
stration would be required. Also there has been considerable concern
regarding the aesthetic impacts of the stacks in the area.
Land Application
Historically, land application of Blue Plains sludge has been part of
the District's solids management program. Approximately 600 to 700 wet tons
per day of dewatered sludge are presently transported off site, stored, and
applied as required to support crop nutrient requirements. Furthermore, the
ES-5
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quality of Blue Plains sludge is good because it is low in metals and toxics
as indicated from recent testing of the sludge. With proper adherence to
regulations, the practice can be safe and poses minimal threat to the
environment.
Concerns about land application relative to its long-term use are the
dependence on contractors to haul, store and land apply the dewatered sludge;
weather constraints; and the requirement for permitted storage and land
application sites. However, the high quality of the Blue Plains sludge is a
positive factor that does encourage long-term acceptance by the farming
community. Furthermore, there is more than sufficient acreage currently
permitted in Virginia and Maryland to handle projected sludge quantities from
Blue Plains during the 20-year planning horizon.
The "land application of dewatered sludge" and "no action" alternatives
are similar but differ in detail and degree. While the "no action" alterna-
tive assumed that there would be no improvements to the sludge dewatering
process, the "land application" alternative assumed that improved dewatering
would be implemented. Similarly, where the "no action" alternative assumed
that sludge handling and disposal constraints might limit loadings to the
plant, the land application alternative assumed that the program would be
constructed and operated so that sludge disposal would not be a constraint on
the capacity of the Blue Plains plant to handle projected influent wastewater
flows during the planning horizon.
Composting and Product Use
Composting of dewatered sludge is a major component of the District's
long-term plan for non-EIS sludge. Under the FONSI, the present on-site
aerated static pile composting is to be replaced with in-vessel composting to
provide increased capacity while using less of the space-constrained Blue
Plains site. On-site composting of the EIS portion of the sludge is not
practical because of the site limitations. Nearly all remaining open space
is being reserved for the anticipated additional wastewater treatment.
ES-6
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Drying and Product Use
Heat drying reduces the overall weight and volume of sludge to be
removed from the site. The final dry sludge pellets, which are stable and
pathogen-free, may be used for land application programs. Environmental
concerns focus on the moist gas stream discharge to the atmosphere and the
liquid sidestream from the scrubber unit.
Experience with heat drying the volume of sludge generated at the Blue
Plains facility is limited. A market for dried sludge pellets has not been
established in the northeastern United States.
Landfilling
The Lorton Landfill in Fairfax County, Virginia is currently the only
site available to accept dewatered sludge. However, the landfill's location
in the Occoquan Watershed, and Commonwealth of Virginia regulations that
prohibit the disposal of dewatered sludge in this basin, would prevent
disposal at this site.
Ocean Disposal
Ocean disposal was evaluated because of the location of Blue Plains on
the shores of the Potomac River. Barges departing from Blue Plains would
have access to the Atlantic Ocean; thus making ocean disposal a low-cost
alternative.
However, ocean disposal sites are not being permitted. The regulatory
trend away from ocean disposal would make site monitoring and management of
ocean disposal operations difficult for the District. If an accidental spill
occurs during the loading of sludge into barges, the risk of polluting the
Potomac River is increased. The U.S. Senate has approved legislation that
would ban ocean dumping of municipal sewage sludge by 1992.
ES-7
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evaluation Factors
Economic Analysis
(Total Equivalent
Annual Costs)
Operability (Includes
reliability, flexibility,
and maintainability)
Implementability (Includes
public acceptability and
management requirements)
Potential Adverse Environmental
Air Impacts
Table ES-1
Comparison of Alternatives
Alternatives
Incineration With In-Vessel Drying & Ocean
Ash Landfill ing Land Application Composting Product Use Landfilling Disposal
6 Units 4 Units
$21,298,000 $19,053,000 $20,218,000 $28,735,000 $15,130,000 $24,704,000 $8,164,000
Stack Emissions
Odor Emissions
Water Impacts
o Surface Water
o Groundwater
Land Impacts
o Transportation
o Land Use Conflicts
o Nutrients Overloading
o Landfill Capacity
o Aesthetics
Other Environmental
Considerations
Moderate
High
X1
xi
xl
Moderate
High
X
X
X3
Moderate
Low
Moderate Moderate
Low
Low
1 Potential impact at landfill; leachate generation from ash residue.
2 Impacts are possible but extremely low because of guidelines and regulatory controls.
3 Potential for nutrient overbadings are remote if state guidelines are followed.
Low
Low
ES-8
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SCREENING AND EVALUATION OF ALTERNATIVES
The screening and evaluation of alternatives was based on economic and
engineering factors that are discussed in Chapter 3 of the EIS, and environ-
mental factors that are discussed in Chapter 4 of the EIS. Table ES-1
provides a summary comparison of r,htst factors for each alternative.
PREFERRED ALTERNATIVE
Land Application of dewatered sludge is EPA's preferred alternative. It
includes the following major elements:
(1) Improved sludge handling and dewatering at Blue Plains.
(2) Continuation and renewal of long-term contracts to haul and dispose
of the sludge including:
o Contracts that provi.dp for disposal of 200 DTPD on average land
and for up to 384 DTPD during the maximum two months of the
year, and
o Contracts that provide for appropriate regulatory management,
environmental impacts mitigation, and traffic control.
(3) Coordination with programmed development of the FONSI'd composting
and with expanded use of MCCF.
The major factors behind EPA's selection of land application include:
(1) Of all of the alternatives, it best meets EPA's goals for maximum
reuse of resources and minimization of energy use.
(2) It is a proven technique with known managerial and technical
characteristics.
(3) There is sufficient land available for application; and a sufficient
number of contractors are willing to implement the program.
(4) Adverse environmental impacts are known to be minor and controll-
able. It has a secondary benefit in that it reduces nutrient runoff
to the Chesapeake Bay.
(5) It keeps the District's options open for implementation of other or
different technologies in the future.
(6) It is economically competitive with other viable alternatives.
ES-9
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CHAPTER ONE
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CHAPTER 1
BACKGROUND AND HISTORY OF THE PROJECT
1.1 BACKGROUND AND PURPOSE OF THE EIS
The Blue Plains Wastewater Treatment Plant, located on the Potomac River
Estuary in Washington, D.C., was originally constructed in 1938 to serve the
District of Columbia. During the past 50 years, the facility has been
expanded and upgraded several times. Although the facility is owned and
operated by the District of Columbia, it has become a regional treatment
plant which receives wastewater from over 70 percent of the Washington
Metropolitan Area. The facility currently treats wastewater from:
o Portions of Prince George's and Montgomery Counties, Maryland;
o Portions of Loudoun, Arlington, and Fairfax Counties, Virginia; and
o The entire District of Columbia.
The last major expansion and upgrade plan for the Blue Plains facility
was developed in October, 1970. The plans called for the Blue Plains
facility to provide advanced wastewater treatment for 419 mgd (later changed
to 309 mgd). The upgrade plan was developed to enhance the water quality of
the Potomac estuary and was one of the recommendations issued by the Potomac
Enforcement Conference of April 1969. As a result, an Environmental Impact
Statement (EIS) for the Blue Plains project was prepared by the EPA Region
III office and released in draft form in April 1972. As part of the upgrade
and expansion plan, it was proposed that sewage sludge generated at the
facility be incinerated on site.
Public concern over the environmental impact of sludge incineration
became a major issue after issuance of the DEIS. In the final EIS (released
in 1.974) , it was stated that an evaluation of potential mercury and beryllium
emissions from the proposed sludge incinerators should not constitute a
threat to public health in the vicinity of the Blue Plains WWTP; however,
there was limited specific information concerning the composition of the
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sludge and the fate of materials processed in sludge incinerators. There-
fore, it was decided that EPA would assume the responsibility for further
investigating the health aspects of the incinerator's emissions, and that the
District's Department of Environmental Services would investigate alterna-
tives to incineration. In addition, EPA decided it would prepare a supple-
ment to the EIS which would report on developments connected with each of the
sludge disposal alternatives; identify the alternative selected for implemen-
tation at Blue Plains; and present a discussion of the consequences of that
action.
In July 1984, the District of Columbia's consultant presented a report
which recommended a long-term sludge disposal plan. The recommended plan
involves the following three components.
o Composting sludge at an existing sludge composting facility in
suburban Maryland;
o Composting sludge at a new sludge composting facility to be
constructed at the Blue Plains site; and
o Sludge incineration in new sludge furnaces to be constructed at the
Blue Plains site.
In response to the proposed sludge incineration alternative, EPA served
notice to prepare an EIS on the ultimate disposal alternatives regarded as
feasible. In August 1984, Findings of No Significant Impact (FONSIs) were
issued for the composting portion of the plan. A Notice of Intent to prepare
an EIS on that portion of sludge to be disposed of at the Blue Plains WWTP
was issued in August 1984. On September 5, 1985, the District of Columbia,
the Washington Suburban Sanitary Commission (WSSC) and the user Counties
signed an Intermunicipal Agreement (IMA) fully endorsing the composting and
incineration methods. The adoption of the incineration method for Blue
Plains; however, was subject to a favorable EIS by EPA.
1-2
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1.2 HISTORY
The Blue Plains Wastewater Treatment Plant located in the District of
Columbia is operated by the D.C. Public Works, Water and Sewer Utility
Administration (WASUA). The plant treats wastewater from the District of
Columbia, sections of Fairfax and Loudoun Counties in Virginia, and sections
of Prince George's and Montgomery Counties in Maryland. These areas and
their geographical relationship to the District and Blue Plains are shown on
Plate 1.1.
A series of agreements dating back to the 1950's defined the arrange-
ments for allocating among the user jurisdictions the treatment and transmis-
sion capacity and the capital costs for wastewater treatment and solids
management for the sludge generated at Blue Plains.
Two primary agreements dictate the present sludge management practices
and preferred option for the planning period.
o The 1984 Sludge Memorandum of Understanding; and,
o The 1985 Intel-municipal Agreement (IMA) .
The 1984 Sludge Memorandum of Understanding provided the mechanism for award-
ing five-year contracts for the hauling and disposal of sludge from Blue
Plains. The contracts will continue in effect until the permanent sludge
disposal facilities at Blue Plains are constructed and accepted by the
District of Columbia for operation. The IMA, which was signed by the
District of Columbia, Washington Suburban Sanitary Commission (WSSC) and the
Counties of Fairfax, Montgomery and Prince George's, established the frame-
work for future allocation of capacity at the Blue Plains facility and
assigned responsibility for long-term sludge management.
The wastewater treatment plant currently has the capacity to provide
advanced treatment at peak flows of 585 mgd with an additional 289 mgd of
primary treatment and disinfection, thus providing a total peak flow capacity
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PLATE I.I
-------
of 874 mgd. Wastewater solids management has become increasingly more diffi-
cult as solids production increases with higher levels of wastewater treat-
ment required by the facility's NPDES Permit and continuing population growth
in the region. The Blue Plains treatment facility currently generates
approximately 1,500 wet tons per day (WTPD) or 300 dry tons per day (DTPD) of
dewatered raw sludge and 500 WTPD (100 DTPD) of dewatered digested sludge
which must be disposed of or recycled. Methods of processing, recycling,
and disposal currently in use include composting, compost distribution, and
land application. The recycling and disposal methods in use require bulk
hauling of lime stabilized raw and digested solids from the treatment plant.
The District has discontinued the practices of co-composting and chemical
fixation'of sludge.
1.2.1 Wastewater Treatment
A historical chronology of events of wastewater treatment and
solids management at the Blue Plains Wastewater Treatment Plant appears in
Table 1.1 at the end of this chapter. The District of Columbia wastewater
system has been in existence for approximately 170 years. During the first
125 years, the wastewater system functioned as a collector of sewage and
stormwater and as a conveyor of these wastewaters to the nearest waterway for
discharge without treatment. The practice of discharging untreated sewage
directly to local waterways and increasing District population created a
dramatic increase in water pollution and concern for public health by 1860.
To improve the local water pollution conditions, many sewer discharge points
were combined and relocated to the southern extreme of the District and were
separated in certain areas by the District between 1870 and 1930. During the
early 1930's the District determined that wastewater treatment was required
prior to discharge in order to control the degree of pollution present in the
Potomac River.
Construction of a wastewater treatment plant at the Blue Plains
site within the District began in 1935 and was completed in 1938. The plant
was initially designed to treat an average daily flow of 130 mgd from 650,000
people. The treatment process consisted of grit removal, grease separation,
and sedimentation. Wastewater solids (sludge) produced by the treatment
1-5
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process were digested, elutriated, and dewatered prior to use as a soil con-
ditioner. By 1951, the plant was expanded to 175 ragd to eliminate existing
capacity problems and provided treatment capabilities for a design population
of 975,000 people. This expansion provided additional sedimentation and
digestion tankage.
With deteriorating water quality conditions again being observed in
the Potomac River as the regional population increased, the District began
planning for secondary treatment. Concurrently, pre- and post-chlorination
facilities and a drying-incineration system were constructed at the plant
between 1951 and 1953. The secondary treatment expansion was completed in
1959. Completion of this project increased the plant treatment capability to
an average daily flow of 240 mgd with 75 percent removal efficiency of
influent biochemical oxygen demand (8005) and suspended solids.
Planning for the next plant expansion to process flows up to 309 mgd
began in 1968. The upgrade plan provided for 90 percent removal efficiency
of BOD5 and suspended solids. Subsequently, the Federal Water Quality
Administration, which later became part of the EPA, set the District's dis-
charge limits in 1969 at 309 mgd annual average daily flow; 5 mg/1 6005; 0.22
mg/1 phosphorus; and 2.4 mg/1 total nitrogen. These limitations required the
District to reevaluate the 1968 proposed expansion plan and initiate research
programs to develop cost effective methods of meeting the discharge limita-
tions. In 1975, denitrification was deferred; the remaining construction
projects were completed in late 1982 providing primary treatment capacity of
874 mgd at peak flow, 585 mgd of peak flow seroiviary trsarrnrtr.c along vi vh a
nitrification system, and a new combined multimedia filtration and chlorina-
tion facility.
1.2.2 Wastewater Solids Management
Wastewater solids management at the District of Columbia Blue
Plains Wastewater Treatment Plant has developed and become more complex with
each expansion of the plant. Initially, the digested dewatered solids were
1-6
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land applied to improve soil characteristics and provide necessary plant
nutrients. The sludge land application users at this time consisted of three
basic groups:
o The largest quantity was distributed at no cost to the general
public, truck farmers and homeowners for land application;
o Government facilities used dewatered sludge mixed with soil
and lime to form a soil conditioner for use in landscape
projects;
o The District land applied the sludge at its penal institution
farms in Lorton, Virginia.
This method of solids management was effective until around 1960 when bio-
logical sludge began to be produced by the new secondary treatment process.
In the early fifties a sludge incineration/drying building was
constructed at Blue Plains which housed three flash dryer-incinerators. The
dried product caused frequent dust explosions and the facility was abandoned
because it failed to pass acceptance tests.
Between 1960 and 1970 little progress was made in establishing an
effective solids processing and disposal program to manage the increasing
sludge volumes. As the sludge production exceeded the demand for land appli-
cation material, the practice of stockpiling sludge on site was instituted.
During this time District public health regulations were adopted that
required the sludge to be cured for one year, air dried, and mixed with soil
prior to giving it to the general public. Also, summer hauling of sludge was
not allowed because of excessive odor problems. These factors resulted in a
constantly increasing inventory of stockpiled sludge which is prominent in
1968 photographs of the plant site. The stockpiled sludge was removed in
1970 under an excavation contract for expansion of the advanced treatment
facilities. The expansion project included a new solids processing building
large enough to contain dissolved air flotation thickeners, vacuum filter
dewatering units, and space for multiple hearth incinerators.
1-7
-------
The District needed an interim solids handling program until the
new solids processing building could be completed; thus discussions with the
other user jurisdictions began. In 1971, an Interim Treatment Program
Agreement was executed which required plant effluent quality upgrading
through chemical addition. Under the agreement, the WSSC was responsible for
excess raw sludge disposal. As a result, the Maryland Environmental Service
(MES), as an agent of the WSSC, implemented the following sludge disposal
programs:
o Sludge trenching in Montgomery and Prince George's Counties;
and,
o Sludge drying with a toroidal dryer at Blue Plains.
After several years of operational problems, strong public and
political opposition and the development of local regulations which made new
sites unavailable, the sludge trenching program ended. Thus, the Maryland
Department of Health and Mental Hygiene stopped permitting sites for
trenching of dewatered sludge.
Maryland Environmental Service contracted with Organic Recycling
for the operation of the sludge drying project. The drying process was never
completely successful due to the sludge characteristics which resulted in a
product with a high dust component. Additionally, the air pollution controls
on the system were never sufficient to meet the District's regulations. This
ultimately led to the termination of the project.
The Blue Plains Sewage Treatment Plant Agreement of 1974 resulted
from further wastewater solids disposal discussions. Under the 1974
agreement, user jurisdictions were responsible for their share of sludge
disposal, based on their allotted flow, until a regional sludge program would
be operational in 1977. During the agreement development period it was
assumed that the incinerators would be operational by 1977. However, EPA
directed deferred incinerator installation in 1975 because of high energy
costs and other related concerns. While the agreements were being reached,
1-8
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approximately 150 DTPD of sludge were being applied to marginal and agricul-
tural lands in Maryland and aerated static pile composting was developed at
the Department of Agriculture's Beltsville Research Center in Maryland.
In 1976, the District proposed a new plan which involved construc-
tion of an interim composting facility at Oxon Cove, Maryland and the redesign
of the Blue Plains combustion system with heat recovery. Based on this plan,
the 1974 Agreement interim deadline was extended to 1978. In addition, a
compost marketing study completed in 1977 indicated there was a potential
market for finished compost in the region. However, the Oxon Cove compost
facility project proposed to handle 120 DTPD, was cancelled in 1978 as the
result of strong local opposition to the project.
The Federal District Court issued a two-part Order to the District,
the WSSC and the Blue Plains user jurisdictions when the Oxon Cove facility
was cancelled. The Order required the District to begin composting on-site
at Blue Plains and the WSSC to construct a composting facility at Site II
near Calverton, Maryland. Subsequently, WSSC had to shift its initial
composting activity to an interim cacility located in Dickerson, Maryland
until local opposition to Site II was resolved in the court system and con-
struction was completed.
The new Blue Plains solids processing building, initially proposed
around 1970, was completed in the summer of 1978. Although the incineration
units were not installed, the building shell and necessary structural founda-
tions were constructed under the contract work.
Lacking a long-term solids disposal solution, the District con-
tinued to evaluate alternatives. An overview study of management options
recommended dewatering the solids on filter presses, mixing it with refuse-
derived fuel (RDF), and incinerating the mixture in on-site incinerators with
heat recovery boilers (JRB Associates, 1979). The District decided not to
implement the study recommendation because the EPA requested that a compre-
hensive feasibility study be performed.
1-9
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The concept of shipping composted material to the Caribbean Islands
for use in soil restoration was evaluated but never developed beyond the
planning stages due to lack of U.S. Department of State and Caribbean govern-
mental support.
During the later part of 1970, the District contracted with a group
holding a license for the Dano drum composting system to develop an offsite
sludge and solid waste composting system using barge transport from Blue
Plains to a downriver site in King George's County, Virginia. However, local
opposition in King George's County stopped the issuance of a building permit
and this project also died.
In 1980, a second contract was structured with Dano to construct an
on-site drum co-composting system using space in the denitrification area at
the wastewater treatment plant site at Blue Plains. The contract supported a
demonstration phase followed by a full operational phase. The demonstration
facilities (200 tons per day) were constructed, operations initiated, and
from 45,000 to 50,000 tons of product were generated. However, product was
poorly composted, contained obvious refuse debris and was unmarketable.
Attempts to dispose of the product in Virginia and West; Virginia were
thwarted by water quality regulators. The contract was therefore terminated,
leaving the District with the disposal of the entire inventory.
The District then awarded a contract to Chem-Fix for the use of the
processed sludge as a sanitary landfill cover material. When this procedure
failed, Chem-Fix elected to switch to land application, which was success-
fully implemented through the duration of the contract.
During 1980, the Maryland Department of Health and Mental Hygiene
required Prince George's County to implement alternative sludge disposal
methods for its allotted quantity of Blue Plains sludge. The County
determined that aerated static pile composting was the best alternative.
Under the direction of the WSSC, the Maryland Environmental Service (MES)
constructed the Western Branch Compost Facility in Prince George's County
designed to process 1,000 WTPD (200 DTPD) adjacent to an existing wastewater
treatment plant.
1-10
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The facility was forced to start operation at 350 WTPD (70 DTPD)
before the construction work was completed and within four months, the ton-
nage went to 1,000 WTPD (200 DTPD). This increase resulted from the Maryland
Health Department's action to prohibit landspreading of sludge at several
locations because of public opposition. Overloading the uncompleted facility
resulted in operational problems and strong odors. The public demanded that
the facility be closed. After construction was completed, the facility
reopened at 350 WTPD (70 DTPD), but continued public pressure due to odor
problems forced the permanent closing of the Western Branch site at the
request of the Prince George's County Government. (19)
Montgomery County was also required to implement sludge disposal
alternatives and likewise determined that aerated static pile composting
provided the best solids management option. To comply with the 1978 court
order for construction of the Site II Compost Facility and because of con-
struction delays, the Dickerson Composting Interim Facility was built.
Designed and constructed by MES, it was completed at the same time sludge
trenching was discontinued. Dickerson was operated under an agreement with a
local citizens group that called for the closing of the facility when Site II
opened.
In 1981, Amendment No. 4 to the Blue Plains Agreement was drafted
and set forth a new schedule for planning. The Agreement called for a long-
term centralized sludge facility at or near Blue Plains to be operational by
the end of 1987 and listed the quantity of sludge to be disposed of by the
user jurisdictions in the interim period. The sludge quantity distribution
no longer represents current conditions. Concurrently, the operational
control of the 1-95 Lorton Landfill owned by the District has been shifted to
Fairfax County, Virginia.
Between 1982 and early 1986, the solids disposal program was moving
in a number of directions. As mentioned earlier, the Dano co-composting and
the chemical fixation on-site sludge projects, started in the early part of
the 1980's, were terminated. Both demonstration projects failed to produce a
final sludge product that could be effectively recycled, marketed or other-
wise disposed of within the region. The WSSC stopped composting at the
1-11
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Western Branch facility and began land application of about 350 WTPD
(70 DTPD) of Prince George's County's allocation. The interim Dickerson
compost facility was also closed with the start-up of the Site II Compost
Facility in 1983. The Site II facility is now known as the Montgomery County
Compost Facility (MCCF).
In May, 1984, the 1981 Amendment No. 4 to the Blue Plains agreement
was superseded by a regional Memorandum of Understanding between Blue Plains
and the WSSC. The 1984 Memorandum established a unified regional approach
for disposing of sludge generated at the Blue Plains facility. Under this
Memorandum, the parties agreed to jointly solicit and enter into contracts
for the hauling and disposal of sludge from Blue Plains. The Memorandum
was based upon the assumption that the contracts would be an interim solution
to sludge management at Blue Plains. In addition, the Memorandum provided
that 400 WTPD of sludge would be composted at the MCCF - Site II.
Since the IMA was reached in 1985, sludge in excess of the
Montgomery County composting facility operating capacity is being managed
under two contracts as a. generic Blue Plains sludge. The JABB (Jones & Artis
Construction Company, BioGro, and Bevaid Brothers) contract covers raw sludge
composting and raw and digested sludge land application. The ADEM (AD+Soil,
EnviroGro, and MTI Construction Company) contract covers raw sludge land
application. At this time, approximately 360 WTPD (72 DTPD) of sludge is
being composted by the aerated static pile method on-site while the WSSC is
composting about 200 WTPD (40 DTPD) at the MCCF. The MCCF is not currently
operating at its 400 WTPD (80 DTPD) design capacity because of strong local
opposition and odor complaints. Based on extensive study by WSSC, compost
pad enclosure, exhaust air scrubbing, and dilution air fans have been added
to the MCCF and are minimizing problems with odor. Upon completion of the
modifications, it is expected that operations at the MCCF will resume at 400
WTPD. The remaining 600 to 700 WTPD (120-140 DTPD) of sludge are being
successfully land applied. The current disposal practices are to continue
until a decision is made on the selection of a long-term sludge management
program.
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1.3 EXISTING FACILITIES
1.3.1 Wastewater Treatment
The Blue Plains Wastewater Treatment Plant processes include
primary treatment, secondary treatment, nitrification, multimedia filtration
and chlorination. The primary and secondary treatment systems are divided
into independent east and west process trains. The existing layout of treat-
ment plant units is as shown in Figure 1.1. The areas where the denitrifica-
tion sedimentation and future basins shown here have not been constructed.
These areas are currently being used for the composting operation and will be
modified for the in-vessel facility and swing sedimentation basins.
Head works processing before primary treatment consists of screen-
ing, pumping, and grit removal. Thirteen mechanically cleaned bar screens
with one-inch clear openings are used to screen Wastewater. The screens have
a design capacity of 1,300 mgd. The pumping stations contain 15 pumps with a
total pump capacity of 1,300 mgd. Grit, which primarily enters through the
combined sewer portion of the collection system, is removed in aerated grit
chambers. The chambers are designed to provide a detention time of 3.4
minutes at a flow of 673 mgd with 10 of 16 units in service.
After the grit is removed, the wastewater flows to the primary
treatment section of the plant. The primary treatment section consists of 16
clarifiers in the west train and 20 clarifiers in the east train. At maximum
flows, the primary clarifiers provide one hour of detention time.
Nonsettleable solids and soluble organics not removed in the
primary treatment units flow into the secondary treatment section for further
processing. Secondary treatment is accomplished by the air-activated sludge
process in four aeration tanks in the east train and two aeration tanks in
the west train. The aeration tanks provide a detention time of two hours at
a flow rate of 309 mgd. An iron salt is added to both primary and secondary
process flows for phosphorus removal. There are 24 secondary sedimentation
tanks which provide an average detention time of 2.7 hours for the sedimenta-
tion process.
1-13
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Following secondary sedimentation, the wastewater is conveyed to the
nitrification reactors for tertiary treatment. Biological nitrification
converts ammonia nitrogen to nitrate nitrogen in 12 aeration tanks that
provide an average detention time of about four hours. There are 28 nitrifi-
cation sedimentation basins that provide an average detention time of 4.5
hours.
The final stage of wastewater treatment consists of multimedia
filtration and chlorination of the nitrification system effluent. Filtration
is accomplished through the use of 36 multimedia gravity flow filters and
prechlorination of the filter feed is practiced to increase filter run time.
Four chlorine contact tanks are located below the filters to provide proper
disinfection. The contact tank detention time at average flow is approxi-
mately 48 minutes prior to discharge into the Potomac River. The ability to
dechlorinate the effluent will be provided when current construction work on
the dechlorination process is completed.
1.3.2 Wastewater Solids Treatment
1.3.2.1 Blue Plains
Wastewater solids generated at Blue Plains as the result of waste-
water treatment undergo further processing prior to disposal. Solids proces-
sing includes thickening, anaerobic digestion, blending, dewatering, and on-
site aerated static pile composting. A flow diagram showing the present
solids treatment management system is shown in Figure 1.2 and the unit
processes are described below. Dewatered sludge which is not processed
further on-site is stored until it can be bulk hauled to off-site process-
ing facilities.
Thickening of the wastewater solids after clarification is accomp-
lished with the use of gravity and dissolved air flotation thickeners. There
are six gravity thickening units that are generally used for primary sludge
thickening but also have the operational flexibility of accepting activated
sludge for thickening. The gravity units produce a thickened sludge contain-
ing about seven percent solids. The waste secondary sludge is thickened by
1-15
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5
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FIGURE 1.2
1-16
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18 dissolved air flotation units which produce a thickened sludge of four to
six percent solids. After the separate thickening of primary sludge and
waste activated sludge each can be pumped either to the digesters or blending
tanks. Generally, 60 percent of the thickened primary is sent to the diges-
tion system and excess thickened primary and biological sludges are pumped to
the blending tanks.
There are 12 anaerobic digesters, each having a liquid volume
capacity of approximately one million gallons. Approximately 100 dry tons of
solids are digested daily and the daily output averages 60 dry tons of solids
with a typical sludge concentration of three percent solids. Methane gas
produced during digestion is stored in two gas storage tanks and used for
maintaining the process or heat. Excess gas is flared when the storage tanks
are full.
Following anaerobic digestion, the digested sludge and waste nitri-
fication sludge are combined and thickened by dissolved air flotation to
improve dewatering. Four dissolved air flotation units are used for this
thickening process and polymer is used in the process to improve the solids
capture rate. The units produce a sludge with a solids concentration of
approximately seven percent.
Prior to dewatering, the digested-waste nitrification sludge and
excess nondigested thickened sludge may be stored in one of four 300,000
gallon blending tanks. Two of these tanks are currently used for lime slurry
storage. Digested-waste nitrification sludge is stored in one of the remain-
ing two tanks while nondigested (raw) sludge is kept in the other.
Sludge dewatering is done on 24 vacuum filters and one centrifuge.
The nondigested raw sludge is dewatered on 15 of the vacuum filters with
typical conditioning chemical doses of 34 percent lime and eight percent
ferric chloride. The remaining nine filters or one centrifuge are used to
dewater the digested-waste nitrification sludge. Digested-waste nitrifica-
tion sludge dewatering usually consists of polymer conditioning with centri-
fuge dewatering followed by post-liming. The back-up method of operation
1-17
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includes lime and ferric chloride conditioning with vacuum filter dewatering.
Once dewatered, the sludge is conveyed to a truck loading area for transport
to the on-site composting operation or storage area.
At the present time, about 360 WTPD (72 DTPD) of dewatered sludge
are being composted on-site using the aerated static pile method. Mixing,
composting, and curing are done in the areas reserved for future and denitri-
fication tank construction. Woodchip and sludge mixing is done with a four-
wheeled horizontal auger mixer. Wheeled loaders with 10 cubic yard buckets
are used for compost pile construction and localized material moving.
Screening and final compost storage areas are located in an adjacent area
also reserved for future tank construction. Operation of the on-site compost
facility is managed under the JABB contract. Compost produced on-site which
meets established quality standards is available for use regionally and the
remaining unused compost is recycled.
1.3.2.2 Off-Site Processing
Dewatered sludge that is not composted at the Blue Plains facility
is stored on-site until it can be loaded on trucks for bulk hauling to off-
site disposal locations. Approximately 800 to 900 WTPD (160-180 DTPD) of
dewatered sludge are transported off-site to be further processed under two
basic programs. WSSC composts approximately 180 to 200 WTPD (36-40 DTPD) at
its 30 acre MCCF site. The facility layout as originally constructed is
shown in Figure 1.3. The compost facility has a design capacity of 400 WTPD
(80 DTPD), but is operating at a reduced level until public concerns related
to odor are resolved.
Dewatered sludge transported by trucks to the MCCF is unloaded in
the mixing building. Wood chips are mixed with the sludge using a roto-
shredder and front-end loaders. The mixture is composted for 21 days on pads
one and two which are in a fixed roof building with movable curtain side
walls. The aeration building in its current configuration has been con-
structed to control odors being generated on site. The 15 horsepower
aeration blowers discharge into a main header system that conveys the air to
a two-stage scrubber and dispersion fan odor control system. The scrubber
1-18
-------
•HUC04N09 I «
i «
X
3 ,-.
x
1-19
FIGURE 1.2
-------
system replaces the large odor filter piles which were unsuccessfully used
during facility start-up. After aeration, the compost is screened on three
vibrating deck screens with dust control hoods and cured for an additional 30
days under positive aeration prior to product distribution. The Maryland
Environmental Service under agreement with WSSC markets all of the compost
produced at the MCCF in the regional area.
The remaining 600 to 700 WTPD (120-140 DTPD) of sludge are cur-
rently being land applied at permitted sites in Maryland and Virginia.
Typically, dewatered sludge is transported from Blue Plains to several permit-
ted sludge lagoon facilities for storage prior to land application. The con-
tractors have permitted sludge storage capacity for approximately 100,000
cubic yards of solids within the regional area. The sludge is transported
from the storage facilities to permitted agricultural fields and applied at
rates to meet crop nutrient requirements in accordance with specific state
regulated procedures. There are about 22,700 acres of land in Maryland and
47,200 acres of land in Virginia permitted for use in the Blue Plains land
application program.
1-20
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1.4 EXPANSION AND UPGRADING PLANS
In July, 1984 the District completed a long-term sludge study (Camp,
Dresser and McKee (2)) to evaluate sludge disposal alternatives in the
region. The study recommended the following solids management plan:
o On an initial feed basis incineration of approximately 50 percent
(180 DTPD) of the sludge with heat recovery;
o In-vessel composting of approximately 23 percent (83 DTPD) of the
sludge on site;
o Composting about 27 percent (97 DTPD) of the sludge at the HCCF -
Site II.
The recommended plan was based on a total sludge production of 350 to
360 DTPD at a flow of 309 mgd and projected future sludge production around
500 DTPD at a flow of 370 mgd. Under the recommended plan the District would
dispose of the incinerator ash at the Lorton Landfill and the WSSC would be
responsible for marketing all of the compost produced.
In 1985, the Blue Plains Intermunicipal Agreement (IMA) was developed
and adopted by the District of Columbia, the Counties of Fairfax, Montgomery,
and Prince George's, and the Washington Suburban Sanitary Commission. This
Agreement was prepared for the purpose of upgrading Blue Plains and related
sludge management facilities. The purpose of the intermunicipal agreement
included the following:
o Supporting expansion of the Blue Plains Wastewater Treatment Plant
to 370 mgd;
o Allocating the Blue Plains wastewater treatment capacity in
accordance with projected 2010 needs;
o Equitably allocating the capital costs of wastewater treatment and
sludge management;
o Equitably allocating the operation and maintenance costs;
o Defining responsibilities of sludge management;
o Defining the process of making future planning decisions;
1-21
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o Providing a mechanism for continuing coordination, cooperation and
communication; and,
o Supporting a continuing water quality monitoring and evaluation
program.
The Agreement addresses interim, and future Blue Plains sludge manage-
ment in Section 5. On an interim basis all sludge produced at the treatment
plant will be processed and disposed of under the contracts (ADEM, JABB, see
below) awarded by the District in 1984, as amended, and the 1984 Sludge
Memorandum of Understanding, as amended. The WSSC, for Montgomery County, is
responsible for disposing of 80 DTPD of sludge from Blue Plains at the MCCF
or by other alternatives for the agreement term. The District agreed to
construct new dewatering and mechanized composting facilities and rehabili-
tate the digesters. The mechanized composting proposal is to process the
equivalent of 114 DTPD of sludge at Blue Plains. A future incineration
facility capable of processing 240 DTPD of sludge was proposed to be con-
structed by the District contingent upon EPA project approval. The equiva-
lent amounts of sludge to be managed under the IMA are shown in Figure 1.4.
The IMA also establishes responsibilities for residuals management and
operational contingency provisions for the sludge management system. The
WSSC is required to remove an equivalent of 114 DTPD of cured sludge compost
which meets specifically defined quality standards in the agreement from the
Blue Plains site. Marketing, distribution, and sale of all compost produced
is the responsibility of the WSSC. Ash, screenings, and grit were to be
disposed of at the 1-95 Landfill in Lorton, Virginia. If the sludge facili-
ties at Blue Plains are inoperable for other than normal repair and main-
tenance or abandonment, the WSSC, in conjunction with Montgomery, Prince
George's, and Fairfax Counties, will be responsible for removing and dispos-
ing up to 240 DTPD of sludge from Blue Plains until the situation is mutually
resolved. In addition, the WSSC and the Counties agreed to secure emergency
sludge disposal services which are to become active when the incinerators are
started up. These emergency disposal services are to be available for use
within three days after notification of need.
1-22
-------
Responsibilities of Sludge
Management as Defined
in the Intermunicipal
Agreement of 1985
Blue Plains Future
Incineration Facility
Equivalent of 240 Dry Tons/Day
MCCF Aerated Static
Pile Composting
Equivalent of
80 Dry Tons/Day
Blue Plains
Future Mechanized
Composting Facility
Equivalent of
114 Dry Tons/Day
SOURCE Blue Plains Intermunicipal
Agreement. 1985
1-23
FIGURE 1.4
-------
In 1985, Engineering-Science, Inc. initiated a series of studies to
develop concept designs; technical, economic and air quality evaluations of
the concept designs; and a recommended design and air permitting strategy as
part of the District's long-term sludge management plan. The following
scheme was developed in the concept design:
o Mechanical composting of 123-132 dry tons of sludge per day at Blue
Plains;
o Composting 87.5 dry tons of sludge per day at the Montgomery County
Composting Facility; and,
o Incinerating an annual average of 200 dry tons of sludge per day
and 384 peak month dry tons of sludge per day at Blue Plains.
The above information is presented in Figure 1.5.
1-24
-------
TABLE 1.1
A CHRONOLOGY OF EVENTS AT THE BLUE PLAINS PLANT
Year Month
1935-1938
1951
1951-1953
1959
1960
1968
1970
1971
1973
1974
1975
Events
Construction of primary treatment plant at Blue
Plains. Designed for 309 mgd.
Disposal by land application began shortly after
the plant became operational.
Plant expansion to treat 175 mgd.
Land application continued.
Construction of pre- and post-chlorination facil-
ities and a drying-incineration system at Blue
Plains. Dryer abandoned.
Land application continued.
Plant expansion for secondary treatment.
Land application continued.
Stockpiling sludge at Blue Plains site.
Upgraded secondary treatment to 309 mgd.
Stockpiled sludge removed under a mass excavation
contract.
Interim Treatment Program Agreement. Greater
dependence on land application under control of
Washington Suburban Sanitary Commission (WSSC).
Maryland Environmental Service implemented a
sludge trenching program for WSSC.
Blue Plains Sewage Treatment Plant Agreement.
User jurisdictions responsible for share of sludge
disposal.
Proposed construction of sludge incinerators at
Blue Plains to be operational by 1977.
Incinerator installation deferred due to high
energy costs.
1-25
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TABLE 1.1 (Cont'd.)
A CHRONOLOGY OF EVENTS AT THE BLUE PLAINS PLANT
Year
Mont.
1976
1977
1978
1979
1980
1981
Events
Land application continued and aerated static pile
composting project began (Dept. of Agriculture,
Beltsville Research Center, Maryland).
Oxon Cove Compost Facility in Maryland proposed.
Marketing compost study concluded a compost market
exists in region.
Oxon Cove Facility abandoned.
Federal District Court ordered the:
o District to construct a compost facility at
Blue Plains
o WSSC construct compost facility in Montgomery
County, Maryland (MCCF - Site II)
Solids processing building at Blue Plains
completed.
Dano Resource Recovery Inc. composting operation
at Blue Plains began.
Maryland Department of Health and Mental Hygiene
stopped permitting trenching sites for dewatered
sludge disposal.
Maryland Environmental Service (MES) constructed
the Western Branch Facility, Prince George's
County.
MES constructed Dickerson Composting Interim
Facility in Maryland.
Amendment to Blue Plains Agreement:
o Proposed central sludge facility
o Listed quantity of sludge for disposal by user
jurisdiction
o Operational control of Lorton Landfill owned by
District was shifted to Fairfax County,
Virginia.
1-26
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TABLE 1.1 (Cont'd.)
A CHRONOLOGY OF EVENTS AT THE BLUE PLAINS PLANT
Year Month
1982
1982
1983
1984
May
July
August
August
1985 September
1985-1986
Events
Advanced treatment: nitrification system and
combined multimedia filtration and chlorination
facility.
Dano Resource Recovery Inc. composting operations
closed.
Western Branch Composting facility closed July 15.
Interim Dickerson Compost facility closed.
Start-up of MCCF - Site II
Memorandum of Understanding between WSSC and Blue
Plains to contract for hauling and disposal of
Blue Plains sludge.
Camp, Dresser and McKee completed "Sludge, Solid
Waste, Co-Disposal Study" for the District recom-
mending a long-term sludge disposal plan.
Notice to Intent to prepare EIS.
Findings of No Significant Impact (FONSIs) issued
for composting portion of COM plan.
Blue Plains Intermunicipal Agreement.
Engineering-Science prepared sludge management
studies for Blue Plains Facility.
o Refer to list of ES reports in reference section.
o Refer to Figure 1.5 for the sludge value
designation used by ES for the fluidized bed
incineration design for the District.
1-27
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Proposed Long-Term
Wastewater Solids
Management Plan for Blue Plains
Wastewater Treatment Plant
Centrifuge Dewatered to
Mechanical Composting at
Blue Plains 123/132
Press Dewatering to
Fluid Bed Incineration at
Blue Plains
200/384
with Ash Landfilling
at Lorton Landfill
88/168
Centrifuge Dewatering
Post-Liming to
Montgomery County
Composting
NOTE: Value Designation - Projected Average Annual Dry Tons of Sludge
per Day/Peak Month Dry Tons of Sludge per Day.
SOURCE: Final Incineration System Concept
Designs for the District of
Columbia Wastewater Treatment
Plant at Blue Plains (Task II-IOF)
October 1986 Engineering Science
FIGURE 1.5
1-28
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CHAPTER TWO
-------
CHAPTER 2
DESCRIPTION OF SLUDGE MANAGEMENT METHODS
2.1 APPLICABLE METHODS
The proposed wastewater solids management plan as outlined in the 1984
Camp Dresser & McKee (COM) Report calls for on-site in-vessel composting,
off-site composting at the Montgomery County Composting Facility (MCCF) and
incineration at Blue Plains. EPA has approved the composting portion of the
plan (Finding of No Significant Impact, August, 1984), but has required that
an EIS be completed for the incineration component. Sludge management
methods considered, in addition to incineration, are:
o No Action
o Land Application
o Composting and Compost Use
o Drying and Product Use
o Landfill ing
o Ocean Disposal
The management methods address only the estimated annual average 200
DTPD or peak month 384 DTPD proposed to be incinerated unless economies of
scale or other factors indicate larger quantities are more suitable. Table
2 1 provides a summary of the process, site, and environmental concerns
related to the management methods. In addition, a flow diagram of the long-
term wastewater solids management alternatives and associated sludge
quantities on a dry ton basis is shown in Figure 2.1.
2-1
-------
TABLE 2.1
SLUDGE MANAGEMENT METHODS
Alternative
INCINERATION/ASH
LANDFILLING
LAND APPLICATION OF
DEWATERED SLUDGE
COMPOSTING/PRODUCT
REUSE
DRYING/PRODUCT
REUSE
LANDFILLING DEUATERED
SLUDGE
OCEAN DISPOSAL
NO ACTION (1)
o Land Application of
Dewatered Sludge
o Composting/Product
Reuse (FONSI)
Multiple Hearth;
Fluidized Bed
Surface Spreading
and Subsurface
Injection of Sludge
Aerated Static Pile;
In-Vessel
Flash Drying
Rotary Drying
Paddle Dryer
Transportation to
Disposal Site
Barge Transporta-
tion to Disposal
Site
Surface Spreading
and Subsurface
Injection of Sludge
In-Vesset
Disposal Site
Blue Plains STP and
Lorton Landfill (Ash
Disposal)
Agricultural/Reclamation
Permitted Sites in
Maryland and Virginia
Blue Plains/DC Regional
Market
Blue Plains STP/Lorton
Landfill/Land Application
Site
(No Permitted Site
Identified)
Atlantic Ocean (Sites
to be located off con-
tinental shelf)
Agricultural/Reclamation
Permitted Sites in
Maryland and Virginia
Blue Plains/DC Regional
Market
Environmental Concerns
o Air emissions
o Groundwater contamination
o Scrubber water disposal
o Participate and ash disposal
o Stack height
o Food chain toxicity
o Surface and groundwater
contamination
o Heavy metal and organic
compound accumulation in
soils
o Odor emissions
o Food chain toxicity
o Surface and groundwater
contamination
o Heavy metal and organic
accumulation in soils
o Air emissions
o Scrubber water disposal
o Paniculate disposal
o Food chain toxicity
o Surface and groundwater
contamination
o Volatile organic
contamination
o Heavy metal and organic
compound accumulation in
soils
o Groundwater contamination
o Volatized organic contamina-
tion
o Aquatic life toxicity
o Human consumption of seafood
o Effects of sedimentation on
aquatic life
o Food chain toxicity
o Surface and groundwater
contamination
o Heavy metal and organic
compound accumulation in
soils
o Air emissions
o Food chain toxicity
o Surface and groundwater
contamination
o Heavy metal and organic
accumulation in soils
(1) Current sludge management program.
2-2
-------
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2.2 NO-ACTION
The use or disposal of sludge solids under a. no action alternative would
result in the use of the existing programs. Land application is the primary
method of use or disposal at 55 percent of the solids, followed by Blue Plains
composting at 29 percent, and composting at the MCCF at 16 percent on a wet
tons basis. The use or disposal processes and approximate quantities of
sludge currently being managed by each process are shown in Figure 2.2.
There is some capacity available to expand the existing methods of use or
disposal. The MCCF is operating at 50 percent of its design capacity. There-
fore, it could potentially process an additional 200 WTPD. The FONSIed in-
vessel composting facility will replace the existing on-site aerated static
pile system and increase the composting capacity to 123 DTPD (585 WTPD). In
addition, utilization of the land application sites in Maryland and Virginia
could be increased.
Increases in sludge management capacity would be minimized by imposition
of a limit on new building construction and sewer connections in the area
served by the collection system. The wastewater flow to the treatment
facilities might be limited to the current capacity, and the resulting
quantity of sludge generated limited.
Potential adverse environmental impacts from the no action alternative
would be dependent on a number of singular or compounding events. If sludge
quantities do not exceed the capacity of the current land application and
composting programs, the level of any pollution would remain at present
levels. Should one of the programs be shutdown for any length of time, sludge
would have to be stockpiled and a pile leachate would be generated. This
leachate could cause surface water and groundwater pollution if not properly
managed.
2-4
-------
Existing Wastewater Sludge
Management at Blue Plains
Wastewater Treatment Plant
Land Application in Maryland and Virginia
700 Wet Tons/Day
(Contract Operation)
MCCF Aerated Static
Pile Composting
200 Wet Tons/Day
(WSSC Operation)
Blue Plains Aerated
Static Pile Composting
360 Wet Tons/Day
(Contract Operation)
SOURCE: District of Columbia Department of
Public Works Bureau of Wastewater
Treatment and Sludge Management
FIGURE 2.2
2-5
-------
Continuation of the current interim sludge disposal practices at the Blue
Plains facility provides a short-term solution to sludge management, and could
through refinements and commitments provide an alternative that would be in
keeping with EPA's sludge management policy. However, long-term sludge
management alternatives that can process the projected quantities of sludge
must be considered for use and implementation. Because the no action alterna-
tive includes land application and composting which are proposed program
alternatives, it will receive further evaluation under these options.
2-6
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23 INCINERATION WITH ASH LANDFILLING
The District proposes to use incineration at Blue Plains with final ash
disposal at the Lorton Landfill as a major component of its long-term sludge
management plan. Approximately 27 percent of the sludge processed in the
United States is incinerated. An EPA inventory of incineration facilities
completed in 1984 identified 268 facilities; of which 156 or 58 percent are
operational. There were 196 multiple hearth furnaces with 61 percent
currently operational, and 54 fluidized-bed furnaces with 46 percent of these
units being operational. The facilities determined to be nonoperational were
either no longer in service, still in construction or startup, being retro-
fitted, or used seasonally. Reasons given for nonuse included finding of
lower cost options, air emission problems or major design and mechanical/
operational problems. Sludge-only incineration by the District could use
either multiple hearth or fluidized bed furnaces. The energy requirements in
terms of using digester gas as an auxiliary fuel and potential energy recovery
through electrical production for each furnace system need to be considered in
the selection process.
2-3.1 Multiple Hearth Furnace (MHF1
A multiple hearth furr.ace consists of a circular steel shell con-
taining refractory hearths with a central rotating shaft and rabble arm
system (see Figure 2.3). Typical furnace sizes range from 7 to 22 feet in
outside diameter containing 4 to 12 hearths (see Appendix F and Reference 3
for facility listing), Cornmrr ,-.ip,-v i ; i es range fro"i . . . • ;.7F'>, vjr;.
operating temperatures of 1,400 to 1,700°F. Dewatered sl.>,ip,e enters the top
of the furnace and is moved downward through the furnace by the rotating
rabble arms. As the sludge is moved by the rabble arms it is broken into
small particles, exposed to hot furnace gases, dried and burned. Natural
gas, digester gas, or oil burners provide start-up and ^ ,( r;l-ircntal heat
required for incineration. Auxiliary furnace equipment , /,'ically consists of
afterburners for flue gas deodorization and scrubbers to meet air quality
standards.
2-7
-------
FLUE GASES OUT
DRYING ZONE
COMBUSTION ZONE
COOLING AIR DISCHARGE
SLUDGE INLET
RABBLE ARM
AT EACH HEARTH
COMBUSTION
AIR RETURN
COOLING ZONE
ASH DISCHARGE
COOLING AIR PAN
Source: Operations Manual Sludge Handling
and Conditioning EPA 430/9-78-002
Cross section of a typical
multiple hearth incinerator.
Figure 2.3
2-8
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The multiple hearth furnace system proposed for Blue Plains would
consist of six, 22.75 foot outside diameter, nine hearth units designed to
incinerate 133 dry tons/day/unit at a 32 percent total solids feed. A flow
diagram of the proposed system is shown in Figure 2.4. The proposed design
assumes a 75 percent availability factor with each unit capable of incinerat-
ing 100 DTPD. Installation of six furnaces provides added redundancy in that
two units are required for the annual average loads of 200 DTPD and three
units required for peak month loads of 384 DTPD at a 96 percent availability
factor.
Energy recovery in the multiple hearth system would depend on waste
heat boilers, a turbo-generator, and use of gas produced on site. Approxi-
mately 660,000 standard cu. ft/day of digester gas are available for use and
could maintain a. furnace exhaust gas temperature of around 900°F. Two drum
natural circulation waste heat boilers rated at 450 psig pressure with 100°F
of superheat are proposed. They would produce an estimated 75,000 Ibs/hr of
steam at average incinerator loadings and 140,000 Ibs/hr of steam at peak
loads. The steam produced by the boilers would be used to drive a turbo-
generator for on-site electrical production. The proposed generator system
would produce 5,000 kw of electricity at average load conditions and around
9,000 kw at peak loadings.
Furnace exhaust gases pass through air pollution control equipment
prior to reaching the stacks. The multiple hearth concept design proposes to
use an afterburner at up to 1,600CF with one second retention time to destroy
odor producing compounds; a Venturi scrubber for major particulate removal; an
aftercooler; and a wet electrostatic precipitator for fine particulate
removal. Before entering the stack, exhaust gases are reheated to 200eF for
white plume suppression. The stack system proposed consists of two 225 foot
stacks with three 4.5 foot diameter flues in each stack.
2.3.2 Fluidized Bed Furnace (FBF)
A fluidized bed furnace consists of a vertical cylindrical vessel
with a grid to support a sandbed in the lower section as shown on Figure
2.5. Injection of dewatered sludge takes place above the support grid and
2-10
-------
SAND
FEED
THERMOCOUPLE
/— SLUDGE
f INLET
^SIGHT
^yy GLASS
FLUIDIZING
AIR INLET
FLUIDIZED:
SAND BED •;.•.• :••/•:
REFRACTER
ARCH
EXHAUST AND ASH
PRESSURE TAP
BURNER
TUYERES
FUEL
GUN
PRESSURE TAP
STARTUP
-i PREHEAT
DBURNER
JT FOR HOT
WINDBOX
CROSS SECTION OF A FLUID BED FURNACE
Source: EPA Process Design Manual Sludge
Treatment and Disposal EPA 625/1-79-011
Figure 2.5
2-11
-------
combustion air moving upward fluidizes the sandbed and sludge. Within the
furnace, sludge moisture is evaporated and dried sludge is incinerated at
1,400 to 1,500°F in the fluidized hot sandbed. Supplemental fuel is supplied
by burners located above or below the support grid. The ash resulting from
the combustion process is carried out of the furnace with exhaust gases and
removed in a scrubber system. (See Appendix F and Reference 3 for incinerator
facility listing.)
The Blue Plains fluidized bed furnace system as proposed by
Engineering-Science (ES) consists of six, 28 foot inside diameter, windbox-
type fluid bed reactors. The units are designed to incinerate 133 dry tons/
day/unit of sludge at 32 percent total solids feed. A flow diagram of the
proposed system is shown in Figure 2.6. The sludge would be introduced to the
furnaces with a top feeding device which includes a steam spreader system.
This type of system is proposed by ES because it will improve combustion
efficiency through proper sludge distribution. The fluid bed furnace proposed
design assumes a 75 percent availability factor with each unit capable of
incinerating 100 DTPD. Installation of six furnaces provides added redundancy
in that two units are required for the annual average loads of 200 DTPD and
three units required for peak month loads of 384 DTPD at a 96 percent avail-
ability factor.
An alternative to the six furnace construction concept is a four
furnace installation. The four unit concept would utilize the same size and
capacity furnaces and necessary auxiliary equipment as the six unit concept.
Two of the furnaces would be required for the annual average loads of 200 DTPD
and three units would be required for peak month loads of 384 DTPD. During
average and peak loading periods the number of furnaces on standby would be
two and one, respectively. In comparison, the six unit concept would have
four and three furnaces on standby at similar loadings. The four furnace
concept would have less inherent redundancy than a six unit system but
equivalent six unit redundancy could be achieved through a flexible sludge
management system. For example, additional redundancy could be provided to a
four furnace system by having land application sites available and/or using
any remaining excess capacity in the proposed composting systems.
2-12
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Energy recovery in the fluid bed system would consist of waste heat
boilers, a turbo-generator, and use of gas produced on-site. An estimated
460,000 standard cubic feet per day of digester gas will be used to maintain
the preheated air temperature in the windbox at approximately 1,140CF. Two
drum natural circulation waste heat boilers rated at 450 psig pressure with
100°F of superheat are proposed. They would produce an estimated 28,000
Ibs/hr of steam at average loadings and 60,000 Ibs/hr of steam at peak
loadings. The steam produced by the boiler would be used to power a turbo-
generator which would produce electricity on-site. The generator would
produce 2,000 kw (kwhr/hr, or 48,000 kwhr/day) of electricity at average load
conditions and an estimated 3,700 kw at peak loads.
Furnace exhaust gases pass through air pollution control equipment
prior to reaching the stacks. The fluid bed concept design proposes to use an
afterburner, a Venturi scrubber, an aftercooler and a wet electro-static
precipitator. The afterburner assures complete combustion of the sludge and
aids in the destruction of volatile organic and nitrogen oxide compounds. The
Venturi scrubber removes the majority of particulate material which is
followed by the wet electrostatic precipitator for fine particulate removal.
The exhaust gases are reheated to 200°F for white plume suppression. The
stack system proposed consists of two 225 foot stacks with three 3.25 foot
diameter flues in each stack.
Fluid bed incinerators require a sand make-up system to replace the
bed material lost through operation. The Blue Plains proposed sand system
would include a sand silo and pneumatic charging system for addition of sand
to the incinerators.
The proper disposal of ash produced by either incinerator system
completes the sludge management task. The multiple hearth incinerator ash
system is a dry process consisting of pneumatic ash conveyance and storage.
The fluid bed incinerator ash system is a wet slurry process consisting of
thickening, dewatering and storage. Typically, incinerator ash which is
landfilled is low in moisture, free of pathogens and organic compounds, and
2-14
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is thus easier to dispose of than a dewatered sludge. The heavy metals con-
tained in the ash are usually in a less soluble oxidized form and when con-
tained in an alkaline environment they are less mobile. Incinerator ash has
been used as a soil conditioner and to supply necessary trace metals to
improve plant growth.
The proposed Blue Plains multiple hearth and fluidized bed incin-
erator systems are projected to produce 88 and 168 dry tons of ash per day at
annual average and peak month loads, respectively. The proposed long-term
management plan indicates that the ash will be landfilled at the Lorton facil-
ity. The District has characterized the expected leachate and ash resulting
froir- incineration through laboratory analysis (see Reference 7 for additional
information). The ash laboratory results are contained in Tables 2.2 and 2.3.
The ash leachate values shown in Table 2.2 are below the established EPA
Extraction Procedures (EP) toxicity characteristics criteria.
Environmental concerns related to incineration and ash landfilling
include air emissions, groundwater contamination, ash and particulate dis-
posal, stack height and scrubber water treatment. Locating the sludge
incinerators at Blue Plains enables the return of scrubber water to the
wastewater treatment system for processing. The proposed multiple hearth
scrubber system would have a recycle flow of 3.2 mgd which is estimated to
contain 8,200 Ibs/day of solids. This is equivalent to an increase of less
than 3 mg/1 in the 370 mgd plant flow. The fluid bed system as proposed would
recycle 1.9 mgd and contain 7,200 Ibs/day of solids which is equivalent to an
increase of less than 3 mg/1 in a 370 mgd plant flow. The disposal of ash and
particulates at the Lorton Landfill will reduce the potential for groundwater
contamination with proper leachate monitoring and control as compared to on-
site stockpiling.
The remaining major concerns are the stack height and the impact of
incineration on the regional air quality. Sludge incineration at Blue Plains
will be regulated by the air pollution laws and guidelines listed below; and
the regulations establish the criteria upon which control equipment are
evaluated.
2-15
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TABLE 2.2
BLUE PLAINS
BLENDED SLUDGE ASH LEACHATE CHARACTERIZATION (1)
(EP Toxicity Test)
Parameter
Concentration
(mg/1 liter leachate)
USEPA's
Maximum Allowable
Concentration (2)
(mg/1)
Arsenic
Mean
Stand. Dev.
Barium
Mean
Stand. Dev.
Cadmium
Mean
Stand. Dev.
Chromium
Mean
Stand. Dev.
Lead
Mean
Stand. Dev.
Mercury
Mean
Stand. Dev.
Selenium
Mean
Stand. Dev.
Silver
Mean
Stand. Dev.
0.007
0.004
0.869
0.422
0.002
0.001
0.140
0.290
0.107
0.290
0.0006
0.0004
0.004
0.003
0.007
0.014
5.0
100.0
1.0
5.0
5.0
0.2
1.0
5.0
NOTE: Sludge Polymer was 0.3% of sludge dry solids
(1) Source: Engineering-Science, "Final Incineration System Concept Design
for the District of Columbia Wastewater Treatment Plant at Blue Plains
(Task II-10F)," October, 1986.
(2) EPA criteria based on 100 times the Primary Drinking Water Standards.
2-16
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2-17
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o New Source Performance Standards (NSPS);
o National Emission Standards for Hazardous Air Pollutants
(NESHAP);
o District of Columbia, Department of Consumer and Regulatory
Affairs (DCRA) Environmental Standards; and
o Prevention of Significant Deterioration (PSD) Requirements.
Generally, air quality standards regulate opacity, ozone, total suspended
particulates, sulfur oxides, lead, nitrogen oxides, odor, and carbon mon-
oxide. Additional new air quality standards are expected for certain heavy
metals and toxic organic compounds.
The District has evaluated both the MHF and FBF alternatives in
detail over a period of time. Based on their evaluation of the systems, the
District has proposed to utilize the fluid bed incinerator alternative for
the following reasons:
o Operational characteristics expected to produce lower NOx and
VOC emissions;
o More energy efficient than a multiple hearth design; and
o As proposed in the concept design, the FBF would not be
subject to PSD review.
This state-of-the-art incineration system proposed at Blue Plains can be
classified as a high technology process. Many of the proposed incinerator
features are yet to be demonstrated and pilot tested in the United States,
such as the scrubber and afterburner arrangements, the combustion chamber
diameter and top loading sludge system. The ability of the new incineration
features and related dewatering components to function as a reliable full-
scale system remains to be determined. The pilot testing of a full-scale FBF
system as proposed should be considered prior to a multiple unit installa-
tion.
2-18
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2.4 LAND APPLICATION
The process of land application involves the spreading of sludge on the
surface or injecting sludge within the upper soil layer. Historically, land
application of Blue Plains sludge has been used as part of the solids manage-
ment program.
Land application can be subdivided into four basic site types which
include: agricultural, forested, land reclamation, and dedicated land sites.
The primary purpose in applying sludge in the first three types is to use the
fertilizer and soil conditioning qualities of the sludge to improve the
existing soil characteristics and plant growth. The goal of dedicated land
application is to maximize the disposal quantity, with use of the sludge
nutrients a secondary concern.
The characteristics of the application site, the rate of application,
and the form of sludge being applied are interdependent factors which affect
a land application program's success. Selecting an application site involves
the review of specific site criteria to determine the potential for impacting
the local environment. The site criteria include depth to groundwater,
distance to surface water, site slope, soil permeability, soil pH, soil
cation exchange capacity, and bedrock depth and type. Minimum distances to
groundwater and surface water are established to reduce the potential for
contamination. The potential for pollution resulting from site runoff
depends on slope and soil permeability. Generally, slopes of less than 15
percent and medium permeability soil are acceptable. Application site soil
pH's at or above 6.5 immobilize most metals and decrease plant uptake of
metals. The soil's ability to hold positive ions (i.e. metals) is a measure
of its cation exchange capacity. A soil having a high cation exchange cap-
acity can retain higher levels of metals than a soil with a low capacity,
thus concern for metal mobility is less in the high capacity soil. Sites
containing fractured bedrock or sinkholes which allow a direct route for
sludge contact with groundwater need to be identified and avoided. Finally,
a buffer zone between human activity areas and the application site is needed
to prevent direct contact with sludge.
2-19
-------
The rate of sludge application will vary based on the site type and
crop nutrient requirements. Application rates to meet crop requirements are
usually based on nitrogen with additional monitoring of the heavy metals;
cadmium, chromium, copper, nickel, mercury, lead, and zinc. High rates of
application require less land area; therefore, the application rate is a
major determining factor in establishing the number of acres a program will
require.
A land application program can use various forms of sludge, including
liquid, dewatered, air-dried, heat-dried, and composted. The degree of
dewatering and processing beyond stabilization is dependent on sludge quanti-
ties, additional handling, and transportation distance to the application
site.
Other factors affecting land application are climate and site avail-
ability. Land application operations are usually restricted during periods
of precipitation, frozen soil, snow covered soil, and saturated soil to
prevent site runoff and soil compaction. Site availability can be limited
by agricultural cropping schedules, public opposition, and development.
Sludge storage facilities and the allocation of additional land for applica-
tion are methods used to overcome cropping schedules and maintain sludge
removal at treatment facilities. Addressing local public opposition is a
site specific task requiring good program management and public relations.
The loss of sites as the result of regional development is a continuing
problem in growth areas.
The present land application program for the Blue Plains wastewater
treatment plant dewatered sludge is managed through a. group of private
contractors over a five year period. The contractors use agricultural sites
located in Maryland and Virginia because there is no available area within
the District. Approximately 600 to 700 WTPD of dewatered sludge are being
transported off site, stored, and applied as required to meet crop nutrient
requirements. Contractors applying the Blue Plains sludge report that the
current agricultural demand for the high quality sludge (low heavy metals
content, see Table 2.4) is greater than the supply, thus sufficient applica-
tion area exists. However, District officials have reported an increase in
2-20
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controversy and public opposition related to land application of sludge as
the region continues to develop. The quantity of sludge being applied
annually is approaching the quantity proposed for incineration. Therefore,
the land application alternative is one management option for which there is
an operational record.
In order to dispose of the average 200 DTPY of sludge over the next 20
years, an estimated 37,700 permitted acres of land would be required. The
land application acreage was determined through the use of the following con-
ditions: an average corn crop nitrogen requirement of 180 Ibs. per acre; a
sludge nitrogen content of 70 Ibs. per ton; a 1.4 application site avail-
ability factor; 32 percent of the sludge applied in Maryland; 68 percent of
the sludge applied in Virginia with a 3 year cycle; and adherence to EPA
regulations. The quantity of sludge (e.g. 32 percent) allocated for disposal
in each state was based on the reported number of permitted acres shown in
Table 2.5. The total acreage requirement would increase from 37,700 to
approximately 59,400 acres if a 5 year application cycle is used at the
Virginia sites. This could be offset by applying a larger quantity of sludge
in Maryland. The typical application site life is beyond 20 years for
cadmium and the most limiting metal (copper) at an annual loading rate of 6.4
dry tons per acre.
There are approximately 69,800 acres of permitted land available for
application of Blue Plains sludge under the present contract management
program (see Table 2.5). This permitted land area exceeds the average
loading area demand. It is important to note that sludge from other treat-
ment facilities has also been permitted for some of the same area, therefore,
the quantity of excess area is difficult to evaluate. The contractors also
have approximately 107,000 cu. yd. (19,300 dry tons) of permitted lagoon
capacity which provides an estimated 96 days of storage at average loadings.
The storage facilities allow the contractors to accept sludge on a regular
schedule and land apply the sludge on an irregular basis.
Land application of sludge has been promoted as a sludge management
method because the practice recycles the resource value of the sludge.
Additionally, the risk of inorganic nitrogen runoff can be reduced if crops
2-21
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TABLE 2.4
BLUE PLAINS
SLUDGE STREAM QUALITY SUMMARY (1)
Parameter
Cadmium
Chromium
Copper
Lead
Mercury
Nickel
PCBs
Zinc
Raw Sludge
ppm
6.5
121.98
267.3
191.7
0.9 (2)
40.64
-
408.6
Digested Sludge
ppm
5.64
109.5
279.3
171.5
-
38.1
-
428.4
Recommended
Maximum
Concentration ppm (3)
25
1,000
1,000
1,000
10
200
10
2,500
(1) Based on monthly sludge analyses provided by the Bureau of Wastewater
Treatment, District of Columbia, January-May 1986.
(2) Based on monthly sludge analyses provided by Enviro-Gro Technologies
from A&L Eastern Agricultural Laboratories Inc., March-July 1986.
(3) Levels reported in, "Criteria and Recommendations for Land Application
of Sludge in the Northeast.
2-22
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TABLE 2.5
SUMMARY OF CONTRACT LAND APPLICATION FACILITIES
State
Maryland
Subtotal
Virginia
County
Caroline
Carroll
Frederick
Howard
Kent
Montgomery
Prince Georges
Queen Annes
Talbot
Caroline
Culpeper
Essex
Fauquier
Goochland
Hanover
King George
King and Queen
King William
Londoun
Louisa
Land Application
Permitted Acreage
Acres (1.2)
Permitted Off-Site
Storage Capacity
Cubic Yards (3)
22,695
3,536
400
6,161
11,957
3,287
6,856
,200
,848
,609
,566
3 .759
20,000
30,000
50,000
17,000
40,000
Subtotal
Total
47.179
69,574
57.000
107,000
(1) Based on information supplied by Enviro-Gro Technologies, BioGro Systems,
Inc., and Ad+Soil, Inc. and reviewed with State agencies.
(2) Sludge from other treatment facilities has also been permitted for some
of the same area.
(3) Based on information supplied by the District, WSSC, and Metropolitan
Washington Council of Governments.
2-23
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TABLE 2.6
BLUE PLAINS
INDIVIDUAL SLUDGE STREAM CHARACTERIZATION SUMMARY
JANUARY - MAY 1986 DATA PERIOD (1)
Dewatered Raw Sludge
Dewatered Digested Sludge
Parameter
Total Nitrogen %
Ammonium Nitrogen %
Phosphorus, Total %
Potassium %
Calcium %
CaCOj Equiv. %
Magnesium %
Iron %
Cadmium ppm
Chromium ppm
Copper ppm
Lead ppm
Vickel ppm
Zinc ppm
Total Volatile Solids %
Soluble Salts %
Moisture %
pH
Average
3.17
0.056
1.42
0.079
10.478
26.83
0.217
8.049
6.5
121.98
267.3
191.7
40.64
408.6
41.02
3.44
81.47
11.80
Minimum
0.97
0 . 0034
0.50
0.04
5.82
15.54
0.121
6.30
4.1
94
190
100
21
300
37
1.07
77.81
11
Maximum
4.65
0.12
1.91
0.142
12.14
31.15
0.301
11.57
9.5
141
440
256
59.5
600
45.3
6.3
85.34
12.82
Average
3.97
0.048
1.36
0.085
11.15
28.54
0.231
7.92
5.64
109.50
279.30
171.5
38.1
428.4
41.51
4.38
85.21
11.65
Minimum
1.60
0 . 0044
0.091
0.031
6.36
17.91
0.114
4.00
3.3
69.5
150.0
104
23
264
35.68
1.31
78.48
10.15
Maximum
7.17
0.114
1.3
0.2
12.92
35.32
0.492
12.8
8.45
200
524
262
57
655
46.07
7.40
84.67
12.17
(1) Based on monthly sludge analyses provided by Che Bureau of Wastevater Treatment,
District of Columbia.
2-24
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are fertilized with sludge rather than nitrogen fertilizer. Assuming
available sludge quality data as shown in Table 2.6 and an average loading
rate, the estimated average fertilizer value for the Blue Plains sludge is
$45.17 per dry ton applied or $289 per acre (see Table 2.7). The estimated
total annual equivalent fertilizer value is approximately $3,297,000.
Environmental concerns related to land application include contamination
of water sources, food chain toxicity, site odors and increased heavy truck
traffic in agricultural areas. State and local regulatory control and
enforcement of land application site operations are designed to minimize
concerns on the part of the local population. The application site permits
and field conditions are reviewed on an annual or multiple year basis
depending on the state location. Land application is a closely regulated
sludge management option which when done in accordance with established
procedures, can be used without adversely impacting the environment.
However, land application does have limitations which must be considered
if it is to be used as a long-term sludge management alternative. These
limitations include:
o Vulnerability to seasonal conditions;
o Field storage capacity constraints;
o Increasing number of regulations; and,
o Strong public opposition to odors, trucks hauling sludge, location
of storage facilities and land application sites.
2-25
-------
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2-26
-------
2.5 COMPOSTING AND PRODUCT USE
Composting of dewatered sludge is a major component of the present
solids management program and will remain as part of the District's long-term
plan. EPA approved the composting component of the plan (Finding of No
Significant Impact) in August 1984. The present on-site aerated static pile
composting is to be replaced with in-vessel composting to provide increased
composting capacity in less area. The present large site area used for
static pile composting will be needed for swing sedimentation tank construc-
tion. Also, the siting and operation of composting facilities off-site with-
in the region is becoming increasingly difficult. The purpose of this
section is to review composting as a process and evaluate its potential for
processing additional quantities of sludge.
Composting is an aerobic process which allows microorganisms to decom-
porse a portion of the organic matter to carbon dioxide and water. Successful
composting occurs in the mesophilic to thermophilic temperature range (130° F
to 160° F). The elevated temperature is attained by biochemical activity in
the composting material, and no input of heat energy is required. The
process develops the temperatures necessary to kill weed seeds and pathogens.
The sludge is usually dewatered and is mixed with a bulking agent prior to
composting. The purpose of the bulking agent, typically wood or bark chips,
is to break up the solids mass and to absorb some of the moisture in the
sludge. The optimum moisture content for composting a mixture of sludge and
wood chips is between 50 to 60 percent by weight. Less moisture causes a
retardation of biochemical activity, and greater moisture may clog pore
spaces between particles, thus restricting oxygen transfer. Such clogging
would encourage anaerobic conditions in the composting mass, with the
resultant generation of unpleasant odors.
Composting of wastewater solids may be accomplished by several
methods. Mechanical units, which confine, mix, and aerate the solids, are
available from several manufacturers. The windrow method and aerated static
pile processes are the conventional composting schemes most commonly used.
Figure 2.7 provides schematic diagrams of the three composting processes.
2-27
-------
Sludge
Windrow Composting
* Screening will normally be accomplished either prior to or ]ust after the curing step.
*' The purpose of curing is provide storage time for the compost at elevated temperature for additional pathogen kill and stabilization
*** The purpose of the bulking agent is to add porosity to the sludge so air can pass through more readily.
SOURCE: OPERATIONS MANUAL SLUDGE HANDLING
AND CONDITIONING. EPA 430/19-78-002
SLUDGE
MIXING
AERATED PILE
21 DAYS
pprv
TI Fn
CURING
30 DAYS
\*/nnn rwip
-------
The windrow method of composting is accomplished by forming the sludge-
bulking agent mixture into long piles having a triangular cross - sections.
The windrows are maintained in an aerobic condition by daily mixing and
turning. This composting method is only suitable for composting digested
solids and requires a large working area which is not available at the Blue
Plains site.
The aerated static pile method was developed at the experimental waste-
water solids composting project at Beltsville, Maryland under the direction
of the U.S. Department of Agriculture using Blue Plains sludge. This method
involves the placement of either raw or digested solids mixed with a bulking
agent over perforated piping. The piping system is connected to an air
blower, which draws air through the pile, thus maintaining aerobic condi-
tions. Aerated static pile composting operations may use either individual
elongated piles or a more compact extended static pile approach. Figure 2.8
illustrates the typical extended static pile operation currently used at Blue
Plain and the MCCF. Odor problems associated with the windrow method for raw
solids are reduced in the forced aeration method. Construction of the swing
sedimentation tanks to allow for plant expansion will reduce the available
space for composting in the future and hinder processing of the existing and
any future increased sludge quantities by the aerated static pile composting
method.
A number of mechanical reactor closed system composting units are
becoming available and operate in a similar manner (see Figure 2.9). The
plug flow composting process commonly used in the mechanical systems mixes
dewatered sludge with a small amount of recycled compost and carbonaceous
material. The mixture is then placed into the reactor chamber where compost-
ing begins. A continual supply of air is diffused into the reactor and off
gases are collected and deodorized prior to release. The degree of mechani-
cal and monitoring complexity varies from one in-vessel system to another.
Microprocessors can be used to monitor the reactor environment and maintain
the optimal composting conditions. Retention time within the composting
reactors and type of curing, whether inside or outside the reactor, are
system and site specific. The final product is similar to that of other
composting methods.
2-29
-------
2-30
Figure 2.8
-------
CO.
MIXER
L
aooo
<
^COMPOSTING
MIX
—
r_f_r ^ ^-fJ
AIR^ ,
^ ^
-
— OUTFEED
MATERIAL -EEO
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AIR
REMOVAL
SYSTEM-
COMPOSTING
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MATERIAL
REMOVAL
SYSTEM
GRADED STONE
AIR
~AIR INPUT
SYSTEM
Rectangular Reactor
INFEED
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REMOVAL
Tunnel Reactor
Cylinder Tower Reactor
OUTTEEO
cowvrro*
MATERUU.
— MFLOW
AUQCRS
MATERIAL
RCMOVM.
AM MANIFOLD
Cross-section of a Tank Dynamic System
Source: Seminar Publication Composting of
Municipal '..'astewater Sludges.
EPA 625/4-85/014
Circular Dynamic Reactor
Schematic Diagram of Various
Mechanical In-Vessel Compost-
ing Systems
Figure 2.9
2-31
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The preliminary concept, developed by Engineering Science, for the
proposed FONSIed Blue Plains in-vessel system may consist of 8 agitated bed
composting bins, each 600 feet long by 20 feet wide by 12.5 feet deep with a
retention time of 21 days for processing the peak loading of 132 DTPD. In
addition, storage areas for recycle compost, curing, and bulking agent along
with mixing areas are to be provided. The complete composting process will
require approximately 8 acres of on-site area as shown in Figure 2.10. The
District's present FONSIed in-vessel facility schedule calls for Phase I
having a capacity of 60 DTPD to be operational in 1992 and a similar Phase II
to be operational in 1995.
The design criteria developed by ES for the proposed in-vessel system
and manufacturer's sizing information were used to develop the concept for
composting an additional 200 to 384 DTPD of sludge at Blue Plains. Based on
the peak month loading of 384 DTPD at 21 percent solids, an estimated 10
additional composting bins would be required. The bins as sized by the manu-
facturer would be 1,000 feet long by 20 feet wide by 12.5 feet deep with only
6 bins required at average loading conditions. Construction of this facility
would require 16 acres of plant site if a standard layout were used.
In early 1988, the District was advised that nitrogen removal would be
required at Blue Plains. The District has evaluated the nitrogen removal
requirement and prepared a preliminary facilities layout showing that nearly
all unallocated site space will be required for the denitrification function.
There is not sufficient space at the plant to compost both the FONSI'd
sludge and the 200/384 DTPD of sludge if a single level, conventional layout
is used. It will be necessary to develop a multiple level bin composting
building to reduce area requirements.
Another way to reduce the area needed for composting is to dewater the
sludge to 30-35% solids instead of the assumed 21%. The sludge compost-
ability evaluation completed by Engineering-Science for the District con-
cluded pulverizing and rewetting of a 32 percent solids sludge cake was
required for adequate sludge composting in their laboratory test unit.
However, a review of compost facility operational surveys has revealed that
2-32
-------
V NMOQ~=
Xc TflRDTTfl M3AO)
NOUVIS ONIOVOIinO 30QITIS Q3U3J.TM3Q'
Figure 2.10
2-33
-------
the City of Windsor, Ontario composts a dewatered sludge with solids as high
as 30 percent and the Upper Occoquan Sewage Authority, Virginia composts a
sludge cake dewatered to approximately 35 percent solids. While neither of
these facilities use an in-vessel system, they indicate that composting a
sludge cake with solids greater than 21 percent and approaching 32 percent
appears to be feasible. In addition, the control of excess moisture in the
feed sludge to a mechanical composting system appears to be a major factor in
the operational success or failure of the system. Therefore, additional full
bed depth and larger scale compost testing using a high solids sludge cake
and maintaining optimum process moisture, would be worthwhile based on the
potential for economic and site area savings.
The final compost produced by the above methods contains a high humus
content similar to peat. It has a slight musty odor, is moist, dark in
color, and can be bagged. Compost is stable, usually has no objectionable
odor, and is largely free of pathogenic organisms and weed seeds. Compost
increases the water holding capacity of sandy soils, improves the structure of
heavy clay soils, and increases the air content of the soils. The organic
matter in compost improves the workability of soils, thereby making it easier
for plant roots to penetrate. Compost contains relatively small amounts of
slow release nitrogen, phosphorus, and potash with a typical fertilizer value
of 1-2-0.2. The primary usefulness of a compost product is as a soil amend-
ment.
Currently, about 100 total average DTPD of sludge are composted at Blue
Plains and the MCCF, resulting in approximately 350 cubic yards/day of
finished product for use/disposal management. Compost produced at the MCCF
has been highly marketable, while Blue Plains compost has been more difficult
to market. Composting all the sludge generated at Blue Plains, approximately
410 DTPD on an annual average basis, would produce an estimated 1,760 cubic
yards/day (624,400 CYPY) of finished compost. The supply of compost result-
ing from the use of a full composting alternative will have a major impact on
the regional supply when considering production from other large facilities
such as Philadelphia and Baltimore.
2-34
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The Washington, D.C. regional market for compost has already been
established through activities at MCCF and Blue Plains. A preliminary
marketing report completed in 1985 by Delchem Sales Inc. for the District
indicated an initial annual potential market for 277,400 cubic yards with an
estimated increase to 1,350,000 cubic yards after ten years of market
penetration. The major problem reported in FY '87 for COMPROft marketing was
that demand exceeded the supply. Retail and wholesale clients in addition to
90 new clients were reportedly lost due to a lack of finished compost. This
latest report indicates the market is well established and could distribute
larger quantities of compost.
Phasing in the in-vessel facility construction and compost production
with the compost market expansion while phasing out the existing land
application program would provide program control. Selection of a full
composting alternative would be assured a better marketing base through
scaeduled compost production increases in contrast to overloading an under
developed market with the full production from the start. The marketing of
this quantity of compost on an annual basis would continue to require an
aggressive program and expansion into new use areas.
Environmental concerns associated with composting can be divided into
on-site and off-site impacts. On-site impacts which could potentially affect
the environment would include compost leachate, odor, dust, and operator
working conditions. Composting facilities that have been operational for a
period of time are not reporting any major operator health problems. Leach-
ate, odor, and dust can be effectively controlled through proper in-vessel
design and operation and their potential environmental impacts can be
mitigated. The off-site concerns would primarily be related to the product
quality and proper use. The lack of industrial discharges to the Blue Plains
treatment plant results in a compost that is low in heavy metals (see Tables
2.4 and 2.6) and, when properly stabilized through the composting process, is
accepted for use as a plant growth substance and soil conditioner.
2-35
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2.6 DRYING AND PRODUCT USE
Sludge drying combined with product use is an alternative to incinerat-
ing a portion of the sludge produced at Blue Plains. This method of sludge
processing and use or disposal has been successfully practiced in Milwaukee,
Wisconsin; Houston, Texas; Chicago, Illinois; and Clayton County, Georgia.
The District's earlier unsuccessful experience with sludge drying was
discussed in the previous chapter. The ability to generate revenue to offset
some of the drying costs through dry product sales has been demonstrated but
varies regionally. Heat drying is a stabilization process that further
reduces pathogens.
The process of heat drying dewatered sludge involves exposing the
sludge directly or indirectly to hot gases resulting in a dried sludge
containing 10 percent or less moisture. While drying the sludge, the tempera-
ture reachs above 80°C but temperatures that would destroy the organic
content of the sludge are avoided. The final product form resulting from
heat drying is usually a small sludge pellet or bead. A schematic of a
direct rotary dryer unit is shown in Figure 2.11. Other types of drying
units include: flash drying, irdlcc----1:, direct-indirect: rotary, toroidal,
spray drying, and solvent extraction drying. Typically, the drying process
is an energy consxoming operatrior
The physical process of drying takes place in three zones within a
drying unit. In the first zone, the sludge temperature is increased to that
of the next zone and little drying occurs. The second zone is the area in
which the majority of evaporation takes place. Sludge particles in this zone
dry from the core toward the outer surface and the surface remains in a
saturated state until the interior water is evaporated at the surface. The
sludge particles are heated only to the wet bulb temperature of the gas
stream as long as moisture remains on the particle surface. Therefore, the
sludge particle temperature is cool when compared to the gas temperature it
is exposed to. In the third zone, the sludge particle surface becomes
unsaturated and the rate of evaporation decreases as the particle temperature
2-36
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AIR
FURNACE
HOT
GASES
1300° TO
1400"*
ROTARY
DRYER
FUEL
BLENDED
SLUDGE
BLENDER
CYC
1
LONE
DRIED
SLUDC
180° F T£
DIRECT DISCHARGE
TO ATMOSPHERE
ATMOSPHERE
FUEL
ATMOSPHERE
f DRIED
FEED SLUDGE SL-UGE
FOR
USE/
DISPOSAL
BURNER
15
-------
begins to increase. The dried sludge then exits the drying unit where it
cools and is either recycled with wet feed material or stored prior to use or
disposal.
The dried sludge product that results from the heat drying process can
be used as a soil conditioner and plant growth substance. The fertilizer
value of the dried product would be approximately the same as the dewatered
sludge. Drying the sludge improves the materials handling in terms of
conveyance, transporting, and application. The overall mass and volume
reduction achieved through drying greatly reduces the number of truck trips
between Blue Plains and regional land application sites. The area required
for on and off site final product storage would be less than dewatered
sludge. The use of silos for product storage would also be less obtrusive in
an agricultural setting than dewatered sludge lagoons. If the dried product
land application uses were prohibited at any time, or storage of product
during periods of low seasonal demand was not acceptable, then disposal of
the product through landfilling or incineration with ash landfilling may
become a process option.
The heat drying sludge process considered for this Blue Plains treatment
plant alternatives evaluation is the direct rotary dryer unit system. The
system could consist of six drying units with four units required during peak
periods and three units utilized at average loads. Each dryer would be a
3-in-l drum design, 12.5 feet in diameter and 42 feet long. Within the dryer
the sludge moves forward through a center cylinder, then back through an
intermediate cylinder and forward through an outer cylinder toward a fan on
the discharge end. Heated air would be provided by a furnace which could
burn natural gas, fuel oil, or other fuels such as digester gas or wood. The
final exhaust air would be passed through an afterburner. The system
requires 580,000 Btu per dry ton of sludge processed which would be equiva-
lent to approximately 1.9 million cubic feet of digester gas at average
loads. Typical dryer inlet air temperatures would be 427°C (800°F) and out-
let temperatures would be about 82°C (180°F) . The average gas temperature in
the dryer would be 121°C (250°F) with cyclone separator exhaust gases
expected to be around 49°C (120°F), The final dried product in a small
pellet form would have a bulk density of 720 to 880 kg/m^ (45 to 55 Ibs/cu.
2-38
-------
ft.)- On-site storage of dried material in a silo would typically be equiva-
lent to 30 days of production. The estimated building area required for the
system described is about 68,000 square feet. This area requirement could be
met by using the sludge combustion area in the solids processing building and
area adjacent to the building.
The preferred use of the dried sludge product would be for a land appli-
cation program. The dried sludge product in the southeast region of the
country has been valued at $20/percent nitrogen/ton of product. A 3.5
percent average nitrogen value for Blue Plains sludge would equate to a
possible market value of $14/ton of product excluding any transportation cost
based on a unit price of $0.20/lb nitrogen. The lower product value is
perceived to be more reflective of the northeast region as indicated by
distributors. If the product were land applied to agricultural fields an
estimated 37,700 acres of permitted land would be required and the existing
land application sites could be used. The dried product form does allow
application for turf grass management which is typically not a use associated
with dewatered sludge.
In the case where land application sites would not be available, dis-
posal of the dried sludge would be necessary. The options for disposal would
be landfilling or incineration.
Environmental concerns associated with the sludge heat drying process
are possible toxic contaminants emitted in the moist gas stream exhausted to
the atmosphere, control of a liquid sidestream from a scrubber unit, and the
dry sludge product itself. Heat dried sludge should not be allowed to become
rewetted prior to application and incorporation into the soil. Rewetting the
product creates a favorable environment for organism regrowth and anaerobic
decompostition which generates noxious odors, particularly in sludges that
were not stabilized prior to drying. Concerns that the dried sludge product
may create conditions for spontaneous fires is reduced through the pelletiza-
tion process.
2-39
-------
Air pollution in the form of odors, volatile compounds, particulates and
visible plume emissions may result from the heat drying system gas exhaust
stream. Passing the exhaust through an afterburner, scrubber, and a plume
suppression system prior to atmospheric discharge would reduce the potential
environmental impact. If a wet scrubber is used, the liquid sidestream
created is usually recycled to the head of the plant for treatment.
2-40
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2.7 LANDFILLING
Sludge landfilling has commonly been used as a disposal method by many
communities. Current reports indicate about 15 percent of the sludge
produced in the United States is being landfilled. Within the political
boundaries of the District, appropriate area for landfilling wastewater
solLds does not exist. Therefore, the District would have to look in
Maryland and Virginia for potential landfill sites. The use of sites outside
the District requires adherence to a number of local and state governing
regulations specific to any given site.
The State of Maryland regulates the disposal of dewatered sludge in
sanitary landfills under Refuse Disposal Regulations Title 10, Subtitle 17,
Chapter 11 and new Chapter 10 Regulations on Sewage Sludge Management have
been approved. The State's regulatory goal is to allow only sludges pontain-
ing no free liquids in landfills. Mixing of sludge with soil to eliminate
free liquids prior to disposal and use as a cover material is considered an
acceptable practice.
The Commonwealth of Virginia regulates the disposal of dewatered sludge
in sanitary landfills under the Solid and Hazardous Waste Management Law
and the Solid Waste Regulations. The Virginia State Health Department has
the regulatory power to stop sludge landfilling when a potential hazard to
human health or the environment is created. The Department's concerns
related to the impact of the 1-95 Lorton Landfill on the Occoquan watershed
have resulted in an order stopping the landfilling of dewatered sludge at the
site .
The landfilling of sludge can be done on either a sludge-only or on a
codisposal basis, which involves the mixing of sludge with municipal solid
waste. Sludge-only landfilling techniques include trenching, area fill
mounds, area fill layers and diked containment. Sludge solids of 20 percent
are required for the support of cover material which should be applied daily.
The soil cover reduces the odor potential and places a barrier between the
sludge and possible vectors which cpuld spread contaminants. Codisposal of
sludge utilizes the absorption characteristic of solid waste to reduce excess
2-41
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sludge moisture. Typically, dewatered sludge containing at least 20 percent
solids is deposited on top of refuse and mixed in, or sludge is mixed with
soil and used as cover material. The rate of sludge disposal that a landfill
can handle depends on the quantity of refuse being delivered and the sludge
solids content. Table 2.8 summarizes the sludge and site characteristics
which need to be considered in the planning selection process.
Various landfill sites surrounding the District have been evaluated in
the past but none have proven to be acceptable. The 1-95 Lorton Landfill,
which previously received sludge, remains the only regional site with any
potential for landfilling. The Virginia Health Department has prohibited the
landfilling of sludge at Lorton due to environmental concerns (e.g. ground-
water contamination). These environmental concerns would have to be addres-
sed and satisfied prior to reuse of the site as a future dewatered sludge.
landfill. Thus, the use of Lorton has limited viability.
Use of the Lorton site as a landfill for Blue Plains sludge would
require truck transportation of the sludge to the site. The round-trip
transport distance to Lorton from the plant is about. 50 miles. Approximately
270 dry tons or 1,500 cubic yards/day of dewatered sludge, including
inorganic conditioning chemicals at a minimum of 20 percent solids, would
have to be transported based on annual average projections. It is assumed
that 25 to 30 cubic yard capacity vehicles would be used which would result
in 60 to 70 truck trips per day, with increased traffic volume during peak
periods. The number of truck trips would increase if local load limits
restrict truck carrying capacities. The ability to store sludge at the
treatment plant would also be necessary to provide scheduling flexibility to
match landfill operational schedules and to adjust to poor weather conditions
that prevent disposal.
The primary environmental concern related to landfilling of sludge is
the potential for groundwater contamination by landfill leachate. Leachate
is generated from the moisture fraction of the sludge in combination with
rainfall percolating through the landfill. The organic acids formed during
the anaerobic decomposition of sludge can enhance the leaching of metals from
the solid waste/sludge mixture. The potential for groundwater contamination
2-42
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can be reduced by covering the landfill, installing a liner and use of a
leachate collection and treatment system. Table 2.9 lists the range of pol-
lutant concentrations commonly found in sludge landfill leachate. Sludge
quality is directly related to the quality of leachate being generated.
Groundwater monitoring wells located above and down the hydraulic
gradient through a landfill provide necessary monitoring information.
Changes in down-gradient groundwater quality usually indicates that leachate
has moved past the liner and that a potential pollution problem may be
developing.
The proper control of gases resulting from the decomposition of organic
matter in a landfill also aids in reducing environmental concerns. The gas
primarily consists of methane, with small amounts of hydrogen sulfide, and
can reach explosive concentrations around buildings within the site area.
Use of a gas collection and venting system has proven to be a successful
control method. The impact of increased truck traffic between Blue Plains
and Lorton on regional air quality must also be considered with this
alternative.
2-44
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TABLE 2.9
RANGE OF CONSTITUENT CONCENTRATIONS IN LEACHATE
FROM SLUDGE LANDFILLS (1)
Constituent
Chloride
Total Organic Carbon
Chemical Oxygen Demand
Calcium
Cadmium
Chromium
Zinc
Mercury
Copper
Iron
Lead
Total Kjeldahl Nitrogen
Fecal Coliform
Fecal Streptococcus
Concentration (2)
20 - 600
1 - 430
100 - 15,000
100 - 26,000
10 - 2,100
0.001 - 0.2
0.01 - 50 (3)
0.01 - 36
0.0002 - 0.0011
0.02 - 37
10 - 350
0.1 - 10 (3)
100 - 3,600
2,400 - 24,000
MPN/100 ml (4)
2,100 - 240,000
MPN/100 ml (4)
(1) Technology transfer, "Environmental Regulations and Technology Use and
Disposal of Municipal Wastewater Sludge", EPA 625/10-84-003
(2) Concentrations are in milligrams per liter unless otherwise noted.
(3) The maximum concentrations shown exceed the limits specified in
40 CFR 261.24 Table 1. These limits define hazardous wastes under RCRA.
(4) MPN/100 ml - Most Probable Number/100 ml.
2-45
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2.8 OCEAN DISPOSAL
To date, ocean disposal has generally not been advocated by EPA as a
management option. However, the disposal of municipal wastewater sludge in
the ocean through an ocean outfall pipe or by vessel has been practiced by a
number of large metropolitan areas. A current report by the EPA Office of
Water Regulations and Standards noted approximately 4 percent of the sludge
produced in the United States is disposed of in the ocean. The Marine
Protection, Research, and Sanctuaries Act (MPRSA) of 1982, P.L. 92-532, and
as amended by P.L. 99-272, April 7, 1986, regulates ocean disposal and
requires EPA to select appropriate disposal sites. After evaluating suitable
ocean disposal sites, EPA has designated the use of deepwater areas beyond
the edge of the continental shelf. The use of deepwater disposal sites
increases the separation distance from other competing ocean uses and
generally decreases the degree of disposal impact. The EPA issuance of an
ocean disposal site permit to the District would require the demonstration
that no practicable alternative is available that has less impact on the
environment.
Ocean disposal of wastewater solids generated at the Blue Plains Waste-
water Treatment Plant would require thickened and dewatered sludge to be
loaded on a vessel at the existing plant dock. The Potomac River and
Chesapeake Bay shipping channels could provide access to the Atlantic Ocean
and a potential deepwater disposal site.
The type of barge equipment needed to transport the sludge to the dis-
posal site would depend on a number of factors. A critical item in the
system planning is the transit time and how it is affected by waterway
traffic and water conditions. Typical barge capacities and travel speeds are
listed in Table 2.10. Estimated round trip mileage to a potential deepwater
site could range from 350 to 450 miles and take 2 to 3 days to complete.
Because of the lengthy travel time, the decision to initiate a trip would be
highly dependent upon long range weather forecasting; thus reliability is
reduced. Barges are usually custom built; therefore, physical dimensions are
2-46
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TABLE 2.10
TYPICAL BARGE CAPACITIES AND SPEED (1)
Barge Capacity Average Velocity. Knots (2)
Barrels Gallons Loaded Unloaded
25,000 1,050,000 6 7
50,000 2,100,000 7 8
100,000 4,200,000 8 10
Draft in
Feet
N/A
18
N/A
(1) Source: Foss Tug, Seattle, Washington, a division of Dillingham
Corporation, various personal interviews with Metropolitan
Engineers/Brown and Caldwell staff members, 1975 through 1976.
Contained in EPA 625/1-79-011
(2) Velocities in open water. Waterway restrictions reduce average speeds.
1 barrel - 159 1 - 42 gallons
1 knot =0.51 m/s - 1.85 km/hr = 1.151 miles/hr
2-47
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not standardized and construction lead times are around two years. Barge
draft increases with capacity and would complicate navigation in the upper
Potomac River.
The District would have to choose between contracting the complete barge
transport services to a private firm or owning the barges and contracting
just the tug services. Large capacity barges would be required because of
the sludge volumes and transit time. Several days to two weeks or more of
sufficient sludge storage would be required for holding solids between
scheduled transit times and during inclement weather periods. Storage
facilities could be constructed on-site or additional barges could be used
for storage.
The EPA regulates ocean disposal activity at a given site by establish-
ing a toxicity threshold of one-hundredth of a concentration proven to be
acutely toxic to marine organisms. The Limiting Permissible Concentration
(LPC) must be maintained outside the disposal site at all times and within
the site for four hours after sludge discharge. The discharge rate for each
vessel, the vessel speed, and ocean conditions required to obtain optimal
mixing are some of the parameters considered to assure that the LPC is not
exceeded.
Upon reaching the disposal site, self-propelled tankers or towed barges
release the sludge which disperses in the vessel's wake. Volatile hydro-
carbons contained in the sludge evaporate from the water and are dispersed
in the atmosphere. The floatable sludge fraction, grease, oil, and scum
remain on the surface and are moved about by the wind and currents at the
disposal site.
The remaining sludge fraction sinks in an expanding cloud toward the
ocean floor with the heavier sludge particles sinking ahead of the cloud (see
Figure 2.12). The sinking and sludge material dispersion rates in the dis-
posal area are dependent on temperature, salinity, depth and currents.
Metals and chlorinated hydrocarbons have been observed accumulating at
density gradients in the water column at disposal sites. Organisms living in
the zones of accumulation are exposed to higher levels of contaminants.
2-48
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Accumulation of sludge deposits on the ocean floor are dependent on disposal
site depth, currents, erosional processes and storm activity. Generally, at
the shallow, less turbulent sites, sludge accumulation on the seafloor has
been reported.
Ocean disposal of sludge impacts the site environment, through the
addition of nutrients, pathogens, metals, and organic chemicals. The release
of nutrients at deepwater sites tends to stimulate the ecosystem by adding
limiting nutrients, such as nitrogen, necessary for biomass production.
Increased production of phytoplankton and other plant, life result in changes
in local water quality and species composition. Pathogens released through
sludge disposal may present a health risk to humans who consume shellfish
that have accumulated pathogens. Stabilization of wastewater solids is not
required prior to ocean disposal. However, it reduces the risk of pathogen
exposure and odor potential.
The extent of increased metal and organic chemical concentration
observed at a given disposal site is dependent on the sludge quality. The
constituent concentrations of the Blue Plains sludge are contained in Table
2.6. The accumulation of toxic metals and organic compounds in the food
chain are a concern based on the potential health effects of contaminated
seafood. The biomagnification of metals in the food chain has not been
reported except for methyl mercury. Regulations prohibit disposal of sludge
containing mercury and mercury compounds that could raise background
concentrations by 50 percent after dispersion.
Organic contaminants, such as halogenated hydrocarbons, tend to bioac-
cumulate up the food chain and have persistent long-term effects. Other
compounds, like polycyclic aromatic hydrocarbons, do not tend to biomagnify
and degrade more readily.
The risk of inland waterway pollution and potential health problems
resulting from an accidental spill are also a concern. Spills during loading
can be minimized through design and training. A spill prevention and cleanup
-------
program can also aid in reducing the effect of major spills. As with other
alternatives, proper program management minimizes the potential for environ-
mental impacts resulting from accidents and daily operation.
The increased barge activity on the waterways and its impact on recrea-
tional boating is an additional factor requiring consideration with this
alternative. Bridge openings and potential land transportation delays at the
Woodrow Wilson Bridge at 1-95 are not expected from the barge activity.
2-51
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CHAPTER THREE
-------
CHAPTER 3
COST, OPERATIONAL, AND IMPLEMENTATION
COMPARISON OF SLUDGE MANAGEMENT METHODS
3.1 INTRODUCTION
This chapter begins a three-phased evaluation and screening of sludge
management options. The first phase includes cost, operation and implemen-
tation comparisons of the sludge management methods described in Chapter 2.
The comparison presumes that all of the sludge subject to this EIS (200
DTPD/384 DTPD) is handled/disposed entirely by one of the management methods.
3.2 COST COMPARISON
A present worth analysis has been performed to compare the overall cost
characteristics of the management methods. The present worth of an alterna-
tive is defined as the current value of future capital and operation and
maintenance costs discounted at the EPA stipulated rate. The results of the
present worth analysis are summarized in Table 3.1. Cost details are cor
tained in Appendix G.
The analysis was performed under the following assumptions:
o A 20 year planning period beginning in 1988
o Equipment life of 20 years and structure life of 40 years
o Federal discount rate of 8.625 percent
o No phasing of construction activity
o All construction within current plant site
o Any investments in existing wastevater treatment facilities made
before or during facilities planning are sunk costs and excluded
from the cost analysis.
3-1
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3-2
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The management methods were assigned the ranking shown in the last row
of Table 3.1 based on their equivalent cost values. Ocean disposal has the
lowest overall and unit cost as compared with composting which has the
highest unit cost. In terms of cost, the six unit sludge incineration with
ash landfilling alternative, which is proposed by the District, ranks fifth
out of the seven alternatives. The four unit incineration option ranked
third. The second and fourth ranked alternatives respectively are drying
with product use and land application with product use.
The cost analysis is limited to the existing conditions. Alternatives
which are highly dependent on private sector contracts (such as land applica-
tion) have a higher risk of a substantial increase in unit cost over the
period(l). This risk factor is not reflected in the evaluation, but must be
considered in the overall decision making process. Generally, methods which
maximize fixed cost and minimize variable costs (e.g. annual O&M costs) have
a lower likelihood of varying substantially from the cost estimate results
shown here.
The component costs per dry ton for each method are summarized in Table
3.2. The impact of upgrading the dewatering process is reflected in all of
the methods except ocean disposal. The composting, land application, and
landfilling cost evaluations assume the use of centrifuge dewatering units
which would be installed in the existing Solids Processing Building. The
land application and landfilling costs include the chemical cost for
post-liming and account for the additional disposal tonnage resulting from
the lime addition. The in-vessel composting facility capital cost factor was
developed on a peak facility loading of 384 DTPD.
The incineration, drying, and composting component values include
credits for power, dry product contract sale revenue and compost product
contract sale revenue. It was assumed the District staff would not be
involved with the marketing, transportation, and distribution of sludge
products. These activities would be completed by a contractor who would also
guarantee removal of the sludge product from the site on a regular basis.
Multiple competitive bid contracts with long-terms of at least 5 years
and fee increases limited by an appropriate economic index represent
management practices available to lower the risk of increase.
3-3
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The product unit prices shown in Appendix G are based on discussions with
sludge product distribution firms; are intended to be conservative; and would
ultimately be set by future product availability and demand.
3.3 OPERABILITY EVALUATION
Assessment of operabilitv provides a measure of the ability of a given
solids management system to continuously provide the intended disposal
service. The evaluation of operability includes the following three factors:
o Reliability;
o Flexibility; and
o Maintainability.
Reliability concerns the propensity of the process to continually
function over the planning period. Flexibility is a measure of the system's
ability to adapt to changing conditions and meet the disposal requirements.
Maintainability reflects the complexity of equipment, frequency of main-
tenance down time, and maintenance ease. The results of the operability
evaluation are summarized in Table 3.3.
3.3.1 Reliability
The reliability of a given method is judged by a combined measure
of the process complexity and the ability of the District to control the
management system. The greater the complexity, the less reliable the system
because of the greater potential for failure. Also, the greater the degree
of vertical management integration the greater the reliability because of
decreasing impact of uncontrolled factors. The degree of vertical management
integration has been weighted equally with system complexity in this rating.
A major component of each system management includes the labor
requirements. Generally, the greater the complexity or dependence on high
technology and the longer the operating period, the greater the impact of the
labor component on system reliability. The incineration method is dependent
3-5
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TABLE 3.3
SUMMARY OF OPERABILITY EVALUATION
OveralI
Method Reliability<1> Flexibility*2* Maintainability*3* Operabilitv<4>
Incineration With
Ash Landfill ing Moderate Moderate Lou Moderate
Agricultural Land
Application of
Dewatered Sludge Moderate Moderate High Moderate
In-Vessel Composting
and Product Use/
Disposal Moderate Moderate Moderate Moderate
Drying and Product
Use/Disposal Moderate Low Low Low
Landfill ing Dewatered
Sludge
Ocean Disposal
Low
Low
Low
Low
Moderate
Moderate
Low
Low
Note: Rating Value
High - Positive or Desirable; 3
Moderate - Neutral; 2
Low - Negative or Undesirable; 1
Rating ranges, 4-12 possible
4-6 Low
7-9 Moderate
10-12 High
(1) Based on process complexity and management control of system.
*2) Based on the ability to adapt to changing conditions.
(3) Based on equipment complexity, frequency of maintenance, and general accessibility.
<4) calculated by assigning the numerical values noted above, multiplying the reliability
by two and adding across.
3-6
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on the highest skilled labor force over a 24-hour operational period. In
contrast, land application of sludge requires a lower skilled labor force and
the operational period is typically dawn to dusk.
Each of the methods being evaluated has reliability hindering
characteristics over the planning period and none of the alternatives
received a high reliability rating. Incineration has been given a moderate
rating based on its high degree of process complexity and high level of
management control required for the system to remain functional. Drying,
composting, and land application have a moderate rating based on the degree
of risk associated with final product disposal site availability. In addi-
tion, these methods are dependent on private contractors for final use or
disposal of the sludge. Ocean disposal and landfilling methods were given a
low rating because of the assumed unavailability of existing disposal sites,
the current regulatory trend against those forms of disposal, and because
disposal would be dependent on private contractors.
3.3.2 Flexibility
Flexibility is an assessment of a system's ability to adapt to
changing conditions while continuing to meet the disposal requirements.
Methods with minimum dependence on fixed facility processing equipment, with
low energy input, and with readily expandable disposal capacity earn a high
rating. The incineration, land application, and composting methods satisfy a
majority of the flexibility criteria through system redundancy and received a
moderate rating. The drying method has a low rating primarily as the result
of end product characteristics which limit its use. Landfilling and ocean
disposal methods have low ratings because of their inability to meet disposal
needs caused by a lack of potentially permittable disposal sites.
3.3.3 Maintainability
The maintainability rating of a method is based on a number of
criteria. These criteria include the equipment complexity, required degree
of maintenance, and the general accessibility of items to be maintained. The
incineration and drying methods involve the use of large, highly mechanical,
3-7
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high temperature process and air pollution control equipment. These
equipment components by nature require a high level of maintenance.
Therefore, the incineration and drying methods have a low maintainability
rating. The land application method has a high maintainability rating
because it uses a minimum amount of commonly available equipment. Ocean
disposal and composting methods use specialized equipment which is relatively
less complex than the incineration or drying equipment so they are assigned a
moderate rating. Landfilling also receives a moderate rating based on a
concern for leachate pollution and inaccessibility of leachate collection and
containment systems once installed.
3.3.4 Overall Operability
Overall operability is based on a weighted summation of reliabil-
ity, flexibility and maintainability. Reliability is considered to be of
greater importance than flexibility and maintainability and is "weighted" at
twice the value of the other factors. High, moderate, and low ratings of 3,
2, and 1 respectively, were assigned to each factor for each alternative.
The ratings were added and the totals compared. The totals ranged from 6 to
9 with a possible range of 4 to 12. Through the rating procedure, land
application, incineration, and composting received a moderate rating, and
ocean disposal, drying, and landfilling received a low rating.
3-8
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3.4 IMPLEMENTABILITY EVALUATION
The implementability evaluation considers the practicalities of imple-
menting a specific sludge management method. The implementability evaluation
rating provides a method for assessing the factors that affect the successful
implementation of the methods based on public and institutional realities.
The factors to be considered and assessed are public acceptability and
management concerns.
Unlike the other evaluations, the implementability rating is not in-
dependent, but rather is somewhat dependent on the results of the other
evaluations. This is especially the case with public acceptance which is
influenced by costs, the environmental impacts of the various alternatives,
and project location.
3.4.1 Public Acceptability
Public acceptability of a sludge management method is crucial to
the alternative's total implementability. The degree of public acceptance
for each alternative is listed in Table 3.4 and is based on the historical
and current public reactions related to sludge management in the area. The
landfilling and ocean disposal methods are considered unacceptable because of
the high risk of environmental impact associated with each alternative.
Land application of sludge at existing permitted sites, and
composting at Blue Plains, are presently accepted by the public. Some people
who live in the immediate vicinity of land application sites object to the
odors and to the truck traffic. The District staff have reported that local
opposition groups have been formed in some areas and strong opposition has
resulted in the termination of land application permits. The long-term
public acceptance of land application and composting in the region is dif-
ficult to predict. Public opposition to land application and composting may
increase as the regional population increases. However, this could be offset
through a public relations program.
3-9
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TABLE 3.4
SUMMARY OF IMPLEMEMTABILITY CHARACTERISTICS
Alternative
Public Acceptability
Management Concerns
Overall
Implementability
Rating
Incineration With
Ash Landfill ing
Agricultural Land
Application of
Dewatered Sludge
Public Concern Related to Air
Pollutants
Stack Height
Publicly Acceptable at Most
Current Sites
Local Opposition to Site
Odors, Truck Traffic
o Control of Air Pollutants to Meet
Approved Emission Rates
o Continued Availability of Ash
Landfill Disposal Site
o Maintenance and Repair Scheduling
o Contract Management
o Continue Application Site Avail-
ability, State and any Local
Permit Requirements
o Sludge quality
o Seasonal Limitations
o Hauling Distance
High
High
In-Vessel Composting
and Product Use/
Publicly Acceptable at Blue
Plains (FONSI)
o Very Limited On-Site Area to Con-
struct and Expand Composting
Facility
o Product Marketability
o Contract Sale Management
o Sludge Quality
Moderate
Drying and Product
Use/Disposal
Public Acceptability Unknown
at Blue Plains
o Control of Air Pollutants to
Meet Approved Emission Rates
o Product Marketability
o Contract Application Management
o Continued Application Site Avail-
ability
o Sludge Quality
o Fire Hazards
Moderate
Landfill ing Dewatered
Sludge
Publicly Unacceptable
Ocean Disposal
Publicly Unacceptable
o Approval of Lorton Landfill to
Receive Sludge or Establishment
of a New Disposal Site
o Continued Landfill Capacity
o Control of Leachate and Protection
of Groundwater Quality.
o Contract Tug and Barge Equipment
o Transportation to and from
Disposal Site
o Approval of Disposal Site and
Continued Site Monitoring
Low
Low
3-10
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Public acceptability of both incineration and sludge drying at Blue
Plains is unknown, but both have been accepted in other regional areas.
Public acceptance of these alternatives is dependent on not only the control
but the perception of air pollutants at levels below which health related
concerns are an issue. In addition, the public acceptance of the visual
impact of the incinerator stacks where no major stacks exist is difficult to
assess .
3.4.2 Management Concerns
Management concerns associated with the sludge management methods
involve aspects of construction, operation, and maintenance. The concerns
related to each method are shown in Table 3.4. Method has to effectively
address the management concerns to be successfully implemented. The District
staff, for example, have indicated a reluctance to enter a long-term sludge
management program which is heavily dependent on variables beyond the
District's control. This; reluctance is based on experiences with sludge
disposal through the 1970's and early 1980's.
In the view of the District staff, the incineration method provides
a disposal system having a minimum number of variables outside its control.
The success of the incineration method would be dependent on the ability of
highly qualified personnel operating the complex incinerators. In contrast,
the methods which rely on final disposal sites that are not owned by the
District and are impacted by changing public attitudes have more uncontrol-
lable variables.
3.4.3 Overall Imolementability
The overall implementability rating of each method is shown in
Table 3.4. A low rating was assigned to the ocean disposal and landfilling
method because of the lack of public acceptance and existing permitted
disposal sites; and because of the expected difficulty in obtaining a new
disposal site permit.
3-11
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Land application has been given a high implementability ranking.
Land application is currently a functioning management practice which,
through good management to minimize public opposition and meet regulatory
control, could continue to meet the disposal needs. While long-term
availability of sites and continuing regulatory measures require careful
management, this method has proven to be highly implementable.
Drying and product use merits a moderate rating because of uncer-
tainties associated with the ability to control air pollutants cost effect-
ively, and because of questions about final disposal of the product.
Incineration is given high rankings for implementability. Incin-
eration will handle, on a long-term basis, the volumes of sludge designated
for this process. In addition, there is space available for the units and
this technology is functioning and permitted in other areas. The major
concerns with incineration are air pollution and the visual impact of the
stacks.
Lorton landfill is remote from developed areas and is therefore
unlikely to be found more aesthetically unappealing through the disposal of
ash or dewatered sludge. The site is surrounded by trees which provide an
effective visual buffer for all local roadways except the weigh station area
off Furnace Road. No significant aesthetic impact is foreseen from the use
of Lorton landfill as a disposal site.
In-vessel composting is given a moderate rating. The generally
favorable experience with composting, and the decision relative to the
FONSIed portion of the sludge favor its implementability. However, the
severe site restrictions, the substantial structural requirements associated
with "stacking" the in-vessel units, and the somewhat experimental aspects of
constructing and operating an overall composting facility of this size,
partially offset the favorable aspects.
3-12
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3.5 REGULATORY FRAMEWORK
The development of any management method at Blue Plains must abide
within a network of regulations at the Federal, state and local levels. A
list of pertinent regulations relating to sludge handling and disposal are
provided in Appendix A. This section will review some of the regulatory
obstacles that lie in the path of developing any particular method.
3.5.1 Incineration With Ash Disposal
Major considerations here are air pollution regulations for
emissions and disposal of the ash resulting from the incineration process.
Emissions from the incinerator must meet New Source Performance Standards
(NSPS), Prevention of Significant Deterioration (PSD) criteria and District
of Columbia, Department of Consumer and Regulatory Affairs Environmental
Standards.
The proposed air pollution control systems - the afterburner, the
wet scrubber and the wet electrostatic precipitator - would allow the
incineration system to meet existing emission requirements in the area.
Furthermore, with proper attention to restricting the burn rate of sludge,
emissions can be held at levels that would not trigger a PSD review.
Ash generated from the incineration process would be landfilled.
The Lorton Landfill is the logical recipient of the ash. This landfill is
controlled by Commonwealth of Virginia regulations that currently prohibit
the landfilling of dewatered sludge at Lorton because of its location in the
Occoquan River watershed.
3.5.2 Land Application
Land application of dewatered sludge from Blue Plains is currently
used by both Virginia and Maryland. Both states require permits for land
application and have established guidelines for land application siting,
pathogen, nutrient and heavy metal content and for determination of applica-
tion rates.
3-13
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3.5.3 Composting
Composting of Blue Plains sludge is currently performed at Blue
Plains and in Montgomery County, Maryland. The State of Maryland regulates
compost quality, including moisture content and nutrient and metal content.
Maryland requires a distribution permit and both Maryland and Virginia
require permits for construction of a composting facility.
3.5.4 Drying and Product Use
The primary method of disposal of the dried sludge pellets that
result from heat drying sludge is land application. Dried sludge pellets
will have the same properties as dewatered sludge once they are land
applied. Therefore, it is assumed that the regulatory guidelines established
by the Commonwealth of Virginia and the State of Maryland for land applica-
tion will also apply to the dried sludge pellets.
3.5.5 Landfilling
Lorton Landfill in Virginia, which is located in the Occoquan River
watershed, previously received sludge and remains the only regional site with
potential for landfilling dewatered sludge. However, because of concern by
the Commonwealth of Virginia regarding the potential contamination of the
watershed, landfilling of dewatered sludge at the site is prohibited. The
District has evaluated the development of various new landfill sites within
the region but none have met necessary siting specifications.
3.5.6 Ocean Disposal
The Marine Protection, Research and Sanctuaries Act establishes a
schedule for phasing out ocean disposal of sewage sludge in favor of other
land-based management programs. EPA will grant a permit for disposal only if
the applicant can clearly demonstrate that no practicable alternative is
available that has less impact on the environment. In the case where ocean
disposal is deemed a feasible method, locating a suitable site and completing
the permitting process are difficult.
3-14
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3.6 SUMMARY COMPARISON
Table 3.5 provides a summary comparison of the cost, operability and
implementability evaluations for each method. Also included is a ranking
relative to the existing local, state and federal regulations and guidelines.
Incineration and in-vessel composting have a good rating for operability
and implementability but rank fifth and seventh respectively in the cost
analysis. The present worth cost analysis for the incineration alternative
was determined for both the construction of the proposed six unit system and
for construction of a four unit system. Option I (six units) had a higher
cost ranking than option II (four units), placing option II in a moderate
ranking in cost when compared to the other alternatives. Landfilling of
sludge and ocean disposal have low operability and implementability ratings.
Ocean disposal has the lowest present worth ranking while landfilling is
ranked sixth. Land application ranks fourth while drying and product use is
ranked second.
The ocean disposal and landfilling methods have a low ranking within the
existing regulatory framework. Since landfilling of dewatered sludge at the
Lorton Landfill is currently prohibited by the Commonwealth of Virginia, this
method is not feasible until a suitable landfill site is found and permitted.
The current regulatory trend is against ocean disposal and EPA will grant a
permit to the District only if no practicable alternative is available with
less impact to the environment.
Incineration, land application, composting, and drying and product use
all received a moderate regulatory framework ranking. Each of these alterna-
tives must be implemented and operated within a well-defined regulatory
network.
In summary, the incineration, composting, and land application appear to
have moderate operability and regulatory status with moderate to high imple-
mentation potential. The four unit incineration alternative has the lowest
3-15
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cost ranking of this group followed by land application, six unit incinera-
tion, and composting. Landfilling, which has the sixth highest present worth
cost, and ocean disposal, with the lowest, both appear to have the lowest
status for operability and implementability. The regulatory framework, as
previously stated, appears to discourage the use of these alternatives.
3-16
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TABLE 3.5
SUMMARY OF TECHNICAL EVALUATIONS
AND REGULATORY FRAMEWORK
Alternative
Incineration With
Ash Landfilling
Alternative I (*)
Alternative II (**)
Land Application of
Dewatered Sludge
In-Vessel Composting
Drying and Product
Use and Disposal
Landfilling Dewatered
Sludge
Ocean Disposal
Cost
Ranking(1) Operabilitv
Regulatory
Implementabilitv Framework
7
2
Moderate
Moderate
Moderate
Moderate
Low
Low
Low
High
High
High
Moderate
Moderate
Low
Low
Moderate
Moderate
Moderate
Moderate
Moderate
Low
Low
* I - Based on construction of six units.
** II - Based on construction of four units.
Based on Table 3.1 cost evaluation data.
3-17
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CHAPTER FOUR
-------
CHAPTER 4
AFFECTED ENVIRONMENT OF THE
METHODS AND MITIGATIVE MEASURES
4.1 ENVIRONMENTAL IMPACTS OF THE METHODS
The potential impacts of the sludge management methods are reviewed in
terms of their effects on the natural environment and the man-made environ-
ment. Methods evaluated are incineration, land application, composting,
drying and product use, landfilling, ocean disposal and no action. The no
action method is considered the combination of land application and the
FONSI'd composting which proposes the in-vessel composting of 123 DTPD on an
average basis.
Concerns for the natural environment include potential impacts on soil,
water quality, air quality, noise levels and life systems. Impacts on the
man-made environment include effects on the transportation systems, community
facilities, land-use planning, socioeconomics and aesthetic quality. Prior
to any new construction or expansion at the Blue Plains facility, considera-
tion was given to permit requirements, the availability of disposal sites and
the implementability of mitigative measures.
4-1
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4.2 NO ACTION
The no action method at the Blue Plains Wastewater Treatment Plant is
the continuation of land application, and the use of in-vessel composting at
Blue Plains, and composting at the Montgomery County Composting Facility -
Site II.
The present dewatered raw sludge at Blue Plains amounts to about 1,000
WTPD at an average of 17 percent total solids. Dewatered sludge is hauled on
a scheduled basis from the outloading stations to the existing JABB compost-
ing operation, to the Montgomery County Composting Facility (MCCF), or to an
on-site temporary sludge storage tank. From the storage tank, the dewatered
sludge is transported by truck to land application sites.
About 360 WTPD are hauled to the JABB composting operation located on
the Blue Plains site during the midnight to noon time period each day, and
from 150 to 200 WTPD are hauled to the MCCF - Site II location during the
morning to early afternoon hours. The remaining 600 to 700 WTPD are trans-
ferred to the sludge storage tank and hauled off site for land disposal
during daylight hours. (13) Existing sludge management methods at the Blue
Plains facility and those proposed by the District of Columbia for the next
20 years are compared on Table 4.1.
TABLE 4.1
EXISTING AND DISTRICT PROPOSED
BLUE PLAINS SLUDGE DISPOSAL METHODS
Composting On- Site
Composting MCCF
Land Application
Incineration
Ash Disposal/Lorton
Landfill
Existing(l)
72.0 DTPD
40.0 DTPD
140.0 DTPD
Percent of Future Percent of
Total (Ave.)(2) Total
28.5
16.0
55.5
123.0 DTPD
87.5 DTPD
200.0 DTPD (3)
(88.0 DTPD)
30
21
49
Total 252.0 DTPD 100 410.5 DTPD 100
(1) District of Columbia, Department of Public Works, Bureau of Wastewater
Treatment and Sludge Management. Calculations based on 20% solids.
(2) Engineering-Science, Task 11-10F, October, 1986.
(3) Incineration results in 88 DTPD to be landfilled.
4-2
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4.2.1 Land Application
A number of environmental problems may result from stockpiling
sludge prior to land application. The potential for leachate formation is
increased, and if the guidelines are not followed, the leachate may
eventually pollute groundwater and surface waters. Surface water pollution
would affect bird and small mammal habitats on the southern shore of the
site. The Potomac River and Oxon Cove provide substantial aquatic habitats
and numerous federal agencies have made an effort to improve water quality
within these areas. Unmanaged leachate could lead to a loss of habitat.
Groundwater pollution could also be a problem where nitrates would be the
major problem if any exist at all.
The stockpiling of dewatered sludge creates conditions for an-
aerobic decomposition and an environment for bacterial growth. This situa-
tion could result in odors which are difficult to control.
Measures to reduce the impacts of increased solids include:
o Off-site storage facilities;
o Expansion of sludge product market;
o Diversion of wastewater to other treatment facilities; and
o Limits on new construction in the area served by the
collection system.
Approximately 600 to 700 WTPD of dewatered sludge are presently
being transported from Blue Plains, stored and applied to meet crop nutrient
requirements at specific application sties in Maryland and Virginia.
The potential for overloading the soils with nutrients and trace
metals affects the acceptability of land application. Metal accumulations in
soils are strictly regulated by Maryland and Virginia. The transfer of
metals into soils depends on the metal content of the sludge. Blue Plains
sludge contains low concentrations of metals thus reducing the impact from
contamination of the soils at the application sites. An estimate of the
loading rates for nutrients and regulated metals from the Blue Plains sludge
4-3
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appears in Table 4.13. It is important to note that the calculation of
loading rates and life expectancies for land application sites is affected by
the topography, soil characteristics and the potential for pollution of
surface and groundwater at a particular site.
Land application of sludge may pose a public health risk if certain
spore-forming bacteria or parasite ova are transferred to the site. Plants,
especially root crops, may pick up contaminants and run-off from agricultural
fields where sludge has been applied may also pollute surface waters. If
groundwater is polluted, wells that are the source of drinking water for some
residences may become contaminated. A number of criteria and processes which
are described in Section 4.4 have been established by regulatory agencies
which significantly reduce the risk to the public from pathogens in sludge.
The dewatered sludge to be used for land application will be
transported from the Blue Plains site to permitted storage lagoons. Proper
maintenance and operation of the storage lagoons is necessary to avoid
spillage of sludge and leachate formation.
4.2.2 Composting
Environmental concerns associated with existing composting opera-
tions include odor and leachate formation. Proper management of the compost
operation is necessary to produce a quality product. In general, leachate
and odor problems depend upon the moisture content of the compost and can be
controlled with proper site management and leachate collection systems.
Proper aeration and mixing of the compost material should help to reduce odor
and moisture problems. The composting area at Blue Plains contains a
leachate collection system and the potential for surface or groundwater
contamination should be controlled.
Personnel at Blue Plains report problems with the composting opera-
tion caused by excessive moisture and mechanical problems with the aeration
equipment. At the present time, approximately 75 percent of the compost is
being recycled back into the compost pile as bulking material and for use as
4-4
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cover for the sides of the piles. The remaining 25 percent is supplied to
the District for use as soil conditioner by the Parks Department, Fort Meyer
and Washington National Airport.
Blue Plains staff report that much emphasis is being placed on
producing a marketable compost material. The District plans to contract with
a marketing service to find and develop a market for sludge compost. The
delays in marketing Blue Plains compost are, in part, attributable to the
fact that Maryland requires a general distribution permit and before a permit
can be obtained, the compost must meet certain quality criteria.
Blue Plains is planning to replace their aerated static-pile
composting operation with an enclosed in-vessel system. This facility would
handle an average of 123 DTPD and has already received a Finding of No
Significant Impact. Current planning by Blue Plains would have this facility
fully operational by 1995. The District plan indicates that a Phase I
composting project capable of processing about 60 DTPD will be completed by
1992 and a Phase II project of similar capacity by 1995. Impacts from this
facility would be similar to those outlined in Section 4.5, Composting, of
this Chapter.
Space at Blue Plains has been set aside for this in-vessel
operation and should not conflict with planned construction of denitrifica-
tion facilities at Blue Plains.
Composting operations at the MCCF Site II have been successful and
little difficulty in marketing the compost has occurred. Site II is present-
ly operating at 50 percent capacity and could handle an additional 200 WTPD.
Efforts to expand the Site II operation have been met with opposition by
nearby residents who fear the potential for odor from the dewatered sludge.
Compost has only a slight musty odor and should not contribute to odor
problems.
4-5
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The composting alternative for managing sludge represents an
environmentally acceptable practice. Proper management of the composting
operations can result in a high quality soil conditioner that is
environmentally safe.
4.2.3 Man-Made Environmental Impacts
The primary method of transporting dewatered sludge to storage
facilities and land application sites is by large capacity trucks. Trucks
are also necessary to deliver compost material to buyers. Both of these
methods are dependent on a large number of trucks and can have a significant
impact on the regional transportation system. Traffic flow patterns on 1-295
and 1-95 would be affected by trucks entering and leaving the Blue Plains
site. Trucks emit pollutants that would contribute to existing regional air
quality problems. The region around Blue Plains is a nonattainment area (NA)
for ozone and carbon monoxide. Any truck noise due to the large number of
trucks would be buffered by other vehicular traffic on 1-295 and 1-95. (See
References #1 and 2, COM, District of Columbia Final Report, Sludge, Solid
Waste, Co-Disposal Study and Supplemental Report, July 1984).
The present composting operations and land application practices
are managed through a group of contractors. The District feels that depen-
dence on outside contractors makes them vulnerable to labor disputes and
general uncertainty due to the lack of management control. Another variable
they perceive is the extent of the compost market. The District is presently
exploring the idea of contracting with a marketing service in an effort to
stabilize the composting operations and gain access to the marketplace.
The availability of land application sites for Blue Plains sludge
disposal has frequently been an issue. Currently there are 22,695 acres in
Maryland permitted to receive sludge. Virginia has permitted 47,179 acres.
Table 2.5 in Chapter 2 provides a summary of contract land applications in
the various counties in Maryland and Virginia.
4-6
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It should be noted that both Virginia and Maryland do not permit
sites exclusively for Blue Plains sludge, but from several wastewater treat-
ment plants. Nevertheless, there is adequate permitted land available for
the foreseeable future to dispose of the 200 dry tons per year of sludge that
is the concern of this EIS.
Public acceptance, which is crucial to the success of any sludge
management alternative, will remain a major consideration in the use of
sludge on agricultural lands. Farmers are interested in using sludge and
compost to reduce commercial fertilizer costs within state or federal
guideline.
4-7
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4.3 INCINERATION (District's Proposal)
The District of Columbia has proposed to use incineration at Blue Plains
with final ash disposal at the Lorton Landfill as a major component of its
long-term sludge management plan. An average of 200 DTPD of polymer-con-
ditioned dewatered sludge would be incinerated on an annual basis in
fluidized bed furnaces. The ash resulting from the combustion process would
be carried out of the furnace with exhaust gases and removed in a scrubber
system. ~ _,
4.3.1 Air Quality Impacts
Engineering-Science (ES) performed various analyses for the
District of Columbia in order to evaluate the impacts of air emissions on the
ambient air quality in the region surrounding the Blue Plains facility. The
studies identified the specific air pollutants emitted from existing sources
at Blue Plains and projected the levels of the significant air pollutants
emitted from the proposed incineration system as determined through the use
of EPA-approved dispersion models. This section summarizes the findings of
those studies.
4.3.1.1 Regulations
Sludge incineration at Blue Plains will be regulated by the
criteria established by the New Source Performance Standards (NSPS); the
National Emission Standards for Hazardous Air Pollutants (NESHAP); the
District of Columbia, Department of Consumer and Regulatory Affairs (DCRA)
Environmental Standards; and the Prevention of Significant Deterioration
(PSD) standards. The regulated pollutants are ozone (03), total suspended
particulates (TSP), sulfur oxides (SOX), nitrogen oxides (NOX), carbon
monoxide (CO), lead (Pb), mercury (Hg) and beryllium (Be). The control of
visible emissions and odors will fall under the District's regulations.
Since the Blue Plains facility is located within a nonattainment (NA) area
for 03 and CO; thus NA regulations will apply if emissions of CO and volatile
organic compounds (VOC) exceed the established limits. VOCs are precursors
to the formation of 03.
4-8
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The area around the Blue Plains plant is classified as a PSD Class
II area. There are no PSD Class I areas within 10 kilometers of the plant.
The nearest Class I is located 103 kilometers from Blue Plains. Class I
areas are designated environmentally sensitive and have very stringent air
quality deterioration limits. Examples are national parks and wildlife
preserves. Class II areas are those areas which consist of populated and
industrial centers where limited industrial growth is allowed.
According to PSD and District of Columbia regulations, the Blue
Plains facility is presently not considered a major pollution source.
However, a PSD permit review will be required if expected emissions of TSP,
SC>2 or NOx from the proposed sludge incinerators are equal to or greater than
250 tons per year. EPA requires that State Implementation Plans (SIP)
address stationary sources with lead (Pb) levels in excess of 5 tons per year
(40 CFR Part 51). Nonattainment area review will be required if CO or VOC
emissions are equal to or greater than 100 tons per year. The NESHAP
standards regulate emissions of mercury to 3,200 grams and beryllium to 10
grams over a 24-hour period.
The District's regulations are restrictive regarding visible
emissions. Discharges from stationary sources may not exceed 40 percent
opacity for two minutes in a 60-minute period or 12 minutes in any 24-hour
period during start-up, cleaning, soot blowing, adjustment of combustion
controls or malfunction. (DCRA, Section 600.3). Zero opacity emissions are
required at all other times. The District's regulations also prohibit the
emission of odorous or other nuisance air pollutants which are likely to be
injurious to public health and welfare.
4.3.1.2 Emissions - Existing Sources
An analysis of air emissions from existing sources at the Blue
Plains facility determined that the regulated air pollutants were below
the established levels. Table 4.2 summarizes the average annual emissions of
TSP, S(>2, CO, VOC and NOx. The major source of S02, NOx and CO is from the
4-9
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burning of fuel in boilers for space heating. Flaring digester gas emits NOX
and CO. Particulate emissions result primarily from composting operations
and, to a lesser extent, from the boilers.
During the month of February 1986, Engineering-Science (ES)
conducted a sampling program to identify individual VOCs present in the Blue
Plains wastewater influent and effluent. (14) The results are summarized in
Table 4.3 and are shown with results of a similar study performed by Black
and Veatch in 1980. The Black and Veatch study was limited to priority
pollutants as defined by EPA (see Appendix C) while the ES study determined
total VOC emissions.
The Black and Veatch findings were comparable with results of EPA
treatment plant sampling programs in other cities. (48) Concentrations of
VOCs found in the influent at Blue Plains were, on the average, lower than
what was detected in samples from 20 other cities. Also, the frequency of
the occurrence of priority pollutants was generally lower at Blue Plains than
in other cities.
Results of the ES survey indicated several findings:
o No benzene was detected during the Engineering-Science survey,
o Engineering-Science sampling identified 13 VOCs, of which only
eight were priority pollutants,
o Acetone (not a priority pollutant) constituted 86 percent of
the VOCs in the influent.
The ES findings are comparable to those of an EPA study of acetone loading to
receiving waters. (49)
4.3.1.3 Emission Factors
In order to establish criteria to project emissions from the
proposed Blue Plains incineration system, current emission test data from 60
sludge incinerators were reviewed and compiled by the District. The EPA
source data (AP-42 document) was also reviewed but did not include data for
4-10
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TABLE 4.2
AIR EMISSIONS SUMMARY
EXISTING BLUE PLAINS OPERATIONS
Annual Average Emissions
(tons per year)
Process
Uastewater (1)
Treatment
Boilers (2)
Flares (3)
Composting
Total
TSP S09
2 22
-
4 -^
6 22
CO VOC
58
9
3
_L _i
12 58
NOV
ii
33
12
— i
45
(1) Based on Engineering-Science sampling for total and individual VOCs.
(2) Based on burning 194,319 gallons of #2 fuel oil with a sulfur content of
0.2%, 237,713 gallons of #4 fuel oil with a sulfur content of 1% and 374
million cubic feet of digester gas with an H2S content of 4 ppm by
volume.
(3) Based on burning 174 million cubic feet of digester gas in flares.
Source: Engineering-Science, Task 11-14G, December 1986.
4-11
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TABLE 4.3
SUMMARY OF VOCs DETECTED IN BLUE PLAINS INFLUENT
AND EFFLUENT SAMPLES
Average Concentration fug/I)
Pollutant
Methylene Chloride (2)
Acetone
Chloroform (2)
2-Butanone
Bromodichloromethane
Trichloroethene (2)
Chlorodibromomethane
Tetrachloroethene (2)
Toluene (2)
Ethyl Benzene (2)
Xylene
Bromoform (2)
Trans-l,2-Dichloroethane (2)
Benzene (2)
Tetrachloroethylene
Trichloroethylene
Black and Veatch-
1980(1)
Influent Effluent
10
10
31
25
10
44
Engineering-Science-
1986
Influent Effluent
7.1
415.0
5.2
8.8
2.4
0.7
0.8
23.2
3.7
3.9
6.0
1.8
2.5
6.7
196.7
5.5
8.7
7.0
0.14
4.7
3.2
3.2
2.1
3.6
5.0
2.5
(1) Study limited to priority pollutants as defined by EPA. (Appendix C)
(2) Priority pollutant.
Source: Engineering-Science, Task 11-13, October, 1986.
4-12
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fluidized bed systems. The emission factors are used for calculating the
amount of pollutants to be emitted in relation to the amount of sludge that
will be burned each day by the incinerators. Table 4.4 lists the emission
factors for the pollutants for which emission data are available. The
fluidized bed furnace (FBF) is the District of Columbia's preferred tech-
nology for Blue Plains.
The emission factors, assuming the worst case sludge loading rates,
were then used to project the estimated emissions for all pollutants
identified in available test data. These include particulate matter, heavy
metals, sulfur dioxide, nitrogen oxides, VOCs and toxic organic compounds.
4.3.1.4 Emission Rates
Table 4.5 lists the maximum hourly emissions and the annual emis-
sions to be expected from sludge combustion. The projected hourly emissions
were based on a maximum burn rate of 16 dry tons per hour or 384 dry tons per
day with three incinerators operating at 96 percent load. The annual emis-
sions were based on a maximum burn rate of 99,790 tons per year of dry sludge
with three incinerators operating at approximately 70 percent load. This is
an artifically proposed limit on operations to avoid the need for a PSD
review.
Based on the emission factors listed in Table 4.4, the 99,790 tons
per year burn rate is the maximum amount of sludge that can be burned without
triggering review under the Prevention of Significant Deterioration regula-
tions. A burn rate of 99,790 dry tons per year (273.4 dry tons per day)
would emit an estimated 249 tons of nitrogen oxides (NOX) annually. The
District proposes to incinerate an annual average of 200 DTPD or 73,000 dry
tons of sludge per year and 384 DTPD during peak periods. (15)
The emission of VOCs is significant due to their contribution to
ozone formation. Assuming the worst case emission rate of 0.3 pounds of VOCs
per dry ton of sludge, the estimated VOC emissions would be 15 tons per year,
4-13
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TABLE 4.4
EMISSION FACTORS (1)
Controlled Emission Factor (Pounds per Drv Ton Sludee)
Pollutant
TSP
S02
CO
VOC
NOx
Pb
As
Cu
Cd
Cr (hexavalent)
Ni
Zn
Hg
Be
PCB
2,3,7,8 TCDD
(equivalent)
HC1
H2S04
Multiple Hearth Furnace
0.83
2.4
Neg
1.0
9.1
0.0065
0.00009
0.0027
0.0008
0.000000014
0.0002
0.0038
0.0001
0.000009
0.00003
0.000000009
0.3
0.11
Fluidized Bed Furnace
0.84
2.4
Neg
0.3
5.0
0.0011
0 . 00004
0.0004
0.00004
0.000000014
0.0007
0.0023
0.0003
0.000009
0.00003
0.000000009
0.3
0.11
(1) Based on review of emission test data for more than 60 municipal sewage
sludge incinerators and all available data on pollutants.
Source: Engineering-Science, "Air Pollutant Emission Factors for Sludge
Incineration", (Task 11-11), September 1986.
4-14
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TABLE 4.5
ESTIMATED EMISSIONS FOR THE
FLUIDIZED BED FURNACE SYSTEM PROPOSED FOR BLUE PLAINS
Maximum
Hourly Emissions
Pollutant ("pounds per hour) (1)
TSP
S02
CO
VOC
NOx
Pb
As
Cu
Cd
Cr (hexavalent)
Ni
Zn
Hg
Be
PCS
2,3,7,8 TCDD
(equivalent)
HC1
H2S04
13.4
38.4
Neg.
4.8
80.0
0.018
0.0006
0.006
0.0006
0.00000019
0.011
0.037
0.005
0.0001
0.0005
0.00000014
4.8
1.8
Annual Emissions
(tons per year) (2)
42
120
Neg.
15
249
0.055
0.002
0.020
0.002
0.0000007
0.035
0.115
0.015
0.0004
0.001
0.0000004
15
5
Annual Established
Emission Values
(tons per vear) (3)
250(3)
250(3)
100(4)
lOO(^)
250(3)
5.0(5)
NA (7)
NA (7)
NA (7)
NA (7)
NA (7)
NA (7)
3,200 gm/24 hr. (6
10 gm/24 hr. (5
NA (7)
NA (7)
NA (7)
NA (7)
(1) Based on maximum burn rate of 16 dry tons/hour.or 384 DTPD which requires
three incinerators operating at 96% load.
(2) Based on maximum burn rate of 99,790 tons/year of dry sludge which requires
three incinerators operating at approximately 70% load.
(3) Major source determinant based on the prevention of significant deterioration
(PSD) regulations.
(4) Major source determinant based on nonattainment (NA) regulations.
(5) 40 CFR 51; EPA requirements for State Implementation Plans.
(6) NESHAP emission limits.
(7) NA - not currently regulated.
Source: Engineering-Science, Task 11-14G, December 1986.
4-15
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which falls below the established limit of 100 tons per year. With proper
operation of the FBF and proposed afterburner control, VOCs would be
effectively destroyed.
Pollutants of major environmental concern are the metals chromium
(Cr), mercury (Hg), lead (Pb), cadmium (Cd), nickel (Ni) and beryllium (Be)
and the toxic organic compounds, PCBs, dioxins (PCDD), and furans (PCDF).
The inorganic metals interact harmfully with biological systems and are
potentially most dangerous because they have a cumulative effect. The toxic
organics as well as some metals warrant careful consideration due to their
carcinogenic and mutagenic potential.
Hypothetically, all metals are entrained or volatilized in the flue
gas stream in a FBF. Heavy metals such as Cd, Cr, Ni, Pb and As deposit onto
flyash particles and volatilize in the high temperature combustion zone.
Upon cooling these metals are absorbed or condensed onto fine particles and
comprise some portion of the total particulate matter. Volatile metals such
as Hg are volatilized and entrained in the flue gas stream. Emission rates
of the volatile metals (Cd, As, Hg, Zn; and, to a lesser extent Pb) have been
shown to be related to incineration temperatures. Emissions of Ni, Cr and Cu
are only slightly affected by the temperature within sludge incinerators.
(16)
Emission data from other FBF incinerators for mercury (Hg) and
beryllium (Be) are limited but the EPA studies published in 1985 indicate
that the estimated emission rates of Hg and Be from the proposed Blue Plains
sludge incinerators will fall below the NESHAP limit of 3,200 grams and 10
grams per 24-hour period, respectively. (16)
It is significant to note that the emissions of the trace metals
into the atmosphere are dependent upon the metals content of the sludge and
the removal efficiencies of the air pollution control equipment to be used.
Table 2.6 summarizes the metals content of Blue Plains sludge. The Blue
Plains treatment plant receives little flow from heavy industrial discharges,
therefore, metals content of the sludge is low.
4-16
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Although much attention has been directed to dioxins and other
toxic organics, little information is available as to their emissions from
FBF sludge incinerators. Available data on emissions of dioxins from MHF
incinerators show that most of the PCDD (dioxin) compounds detected in sludge
feed are destroyed during the incineration process. (16) The destruction is
dependent upon temperature, residence time and available oxygen for combus-
tion. Additional factors which have been suggested to have an impact on
dioxin formation are:
o The amount of dioxin precursors in the sludge feed; and
o The moisture content of the sludge,
Testing of Blue Plains sludge for the toxic organics shows that these
compounds are below the detectable levels based on EPA Extraction Procedure
(EP) toxicity tests (see Table 2.4).
4.3.1.5 Dispersion Modeling Analysis
The determination of the potential impact for the sludge incinera-
tion system on the National Ambient Air Quality Standards and the potential
for the systems to consume available PSD increments in the area are a
necessary part of this EIS. The methodology used by ES to evaluate the air
quality impacts of the incinerators was based on EPA-approved computer
dispersion models. The models predict the ground level concentrations
expected at all points in the area of concern for the significant air pol-
lutants. The types of models used were the Industrial Source Complex (ISC),
Complex-I, the PTPLU and the Human Exposure Model (HEM).
The area where emissions from the proposed sludge incinerators will
have a significant impact was determined with the UNAMAP series 5 and 6
models (ISCST, ISCLT, Complex-I, PTPLU). The pollutants of concern were
TSP, SC»2 and NOx. Carbon monoxide (CO) was not included because CO emissions
from the existing Blue Plains facility and the proposed incinerators are
negligible. Emission rates used in the analysis were the maximum hourly
emissions corresponding to 100 percent (full) load. (Table 4.5) The 100
percent load condition results in the worst-case air quality impacts.
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Meteorological input data included hourly surface observations of wind speed
and direction, temperature, and cloud cover at the Washington National
Airport and upper air data consisting of morning and afternoon mixing heights
measured at Dulles International Airport.
4.3.1.6 Air Quality Impact Areas
Table 4.6 summarizes the results of the model runs for the deter-
mination of short-term and long-term concentrations of TSP, SC>2 and NOx. The
table indicates that the maximum annual impact for TSP and S02 and the
maximum 24-hour impact for TSP is less than the significance levels. The
maximum distance to the significance levels for the 3-hour and 24-hour con-
centrations of SC>2 are 11.7 km and 3.0 km from Blue Plains, respectively.
The impact area for NOx is a circular area with a 5 km radius. The results
indicate that the 3-hour and 24-hour S02 and the NOX concentrations of 30, 6
and 1.9 ug/m^, respectively, are the only pollutant levels for which the Blue
Plains incinerator impacts are significant. Their impacts are significant
because their concentrations exceed the significance levels of 25, 5 and 1,
respectively. (15)
The largest impact area for which any pollutant would have signifi-
cant impact was determined to be an area 18 km by 13 km (11 miles by 8 miles)
around Blue Plains.
The impact areas described are based on the use of UNAMAP-5 models.
Although the impact areas would be somewhat smaller if computed with the
UNAMAP-6 models, which are an updated version of the UNAMAP-5, the larger
impact areas are more conservative estimates.
4.3.1.7 Existing Ambient Air Quality - PSD Increments
To assess the potential impact of emissions from the proposed
sludge incinerators at Blue Plains on the air quality in the area, the
existing ambient air quality levels and the available PSD increments were
determined. Measured air quality data for monitoring sites operated by the
District, Maryland and Virginia within the impact area of Blue Plains were
4-18
-------
TABLE 4.6
PREDICTED AVERAGE CONCENTRATIONS
Maximum
Distance from Distance to
Averaging Pollutant Concentration (ug/ml) Blue Plains Significant
Pollutant Time
TSP
S02
NOX
Annual
24 -hour
Annual
3-hour
24-hour
Annual
Blue Plains Significance Level^> Plant (km)
0.2
3
0.9
30
6
1.9
1
5
1
25
5
1
3.5
2.0
4.5
2.8
2.0
Levels (km)
b (2)
b (2)
b (2)
11.7
3.0
4.5
(1) Significance levels as defined by USEPA in terms of ambient air quality
impacts.
(2) "b" means there is no impact area because the maximum predicted concentration
is less than the significance level.
Source: Engineering-Science, Task 11-14G, December, 1986.
4-19
-------
reviewed. The concentration levels of the regulated pollutants indicate that
the area is in compliance with the air quality standards except for ozone.
The maximum observed pollutant concentrations within the impact area are
shown in Table 4.7.
The pollutants for which PSD increments have been established are
TSP and SC>2. The available increment is the difference between the existing
air quality levels and the ambient air quality standard or the maximum allow-
able increment, whichever is less. Table 4.8 summarizes the air quality
impacts resulting from the proposed Blue Plains incinerators and other
sources consuming PSD increments. As indicated, the incinerators consume
only a small fraction (less than 10 percent for SC>2 and less than 25 percent
for TSP) of the total available increments.
The maximum S02 concentrations resulting from the proposed incin-
erators and the two other major PSD sources consume less than 18 percent and
8 percent of the 24-hour and 3-hour PSD increments, respectively. (15)
Maximum concentrations for other averaging times or pollutants are below the
significance levels defined by USEPA.
4.3.1.8 Projected Ambient Air Quality
Table 4.7 summarizes both the ambient air quality levels expected
from other air pollution sources in the Blue Plains region combined with
emissions from the proposed incinerators as determined by the UNAMAP-6 dis-
persion models. The analyses indicate that emissions from the proposed
incinerators will not interfere with attainment or maintenance of the
National Ambient Air Quality Standards (NAAQS). Since the incinerators will
consume only a small fraction of the available PSD increments, no significant
deterioration of existing air quality will result. Under the conservative,
worst-case conditions used for analysis, the maximum SC>2 concentrations in
the impact area are 80 percent and 70 percent of the 24-hour and 3-hour
NAAQS, respectively. The annual S(>2 and TSP impacts were not modeled because
the proposed incinerators have an insignificant impact on annual S02 and TSP
concentrations. The maximum annual NOX concentration in the impact area is
70 percent of the NAAQS.
4-20
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TABLE 4.8
PSD INCREMENT CONSUMPTION
Averaging
Pollutant Time
TSP Annual
24 -hour
S02 Annual
24 -hour
3 -hour
Blue Plains Impact (1)
fug/ml)
FBF(4)
0.2
3(3)0)
0.7
8(8)
42(24)
Impact of
All PSD
Sources (2)
(ug/ml)
NM
NM
NM
16(12)
42(25)
Available
PSD
Increment
(ug/ro3.)
19
12
20
91
512
NM - Not modeled because Blue Plains impacts are not significant.
(1) Based on modeling five years of meteorological data.
(2) Based on modeling the worst year of meteorological data.
(3) Numbers in parentheses represent the predicted second highest
concentrations.
(4) Impacts for the fluidized bed furnace are shown although it is not subject
to PSD.
Source: Engineering-Science, Task 11-14G, December, 1986.
4-22
-------
4.3.1.9 Health Risk Assessment
For the purpose of determining the potential impacts on human
health due to pollutants, health risk assessments were made utilizing the
Human Exposure Model (HEM). HEM is used to estimate the population exposed
to air pollutants emitted from stationary sources and the increased
carcinogenic risk associated with this exposure. Analysis for carcinogens or
suspected carcinogens that may be emitted into the environment were performed
in order to estimate the increased cancer risk from a lifetime (70 years)
exposure to the maximum annual concentration. The inputs needed to run the
HEM include stack parameters, plant location, and the estimated maximum
annual emission rates shown on Table 4.5.
The results of the analyses are provided in Table 4.9. They indi-
cate that the increased risk of contracting cancer from emissions of all
carcinogens or suspected carcinogens from the fluidized bed reactors is 0.049
per million for maximum exposed individual. The increased risk of contract-
ing cancer from dioxin emissions is less than 0.02 per million. In setting
NESHAPs, EPA has generally assumed that a one per million risk to the most
exposed individual is acceptable.
The results of the HEM, which used 1980 population data and the
annual concentrations predicted by the ISCLT-5 model indicate the cumulative
number of excess cancers for the entire population located within a 20-kilo-
meter radius of Blue Plains over a 70-year life-span due to emissions of all
pollutants from FBFs. The data on Table 4.9 shows that the expected number
of excess cancers for all pollutants over a 70-year lifetime is 0.00014
(1.4x10 "4-) which is much less than one in 70 years. It should be noted that
risk assessment methodology is performed in a way so that actual risks and
excess cancers are likely to be less than those predicted but extremely
unlikely to be greater.
For noncriteria pollutants with threshold health effects, the ISCLT
model was used with the maximum annual emissions and the five-year STAR
summary to determine maximum concentrations. Pollutants that are carcinogens
4-23
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or suspected carcinogens but have threshold effects levels were also con-
sidered. The maximum concentrations were compared to ambient or reference
concentration criteria based on threshold limit values, other state regula-
tions, or data from EPA's Environmental Criteria and Assessment Office. In
general, such reference criteria are intended to protect the general popula-
tion from chronic health effects. The results of the analysis are shown in
Table 4-10. The maximum annual average concentrations are, in general,
orders of magnitude below the reference ambient criteria values found in the
literature. Therefore, no chronic adverse health impacts are expected from
the proposed incinerator emissions.
4.3.2 Ash Disposal
Although the primary emphasis of this section is the impacts of
incinerating sludge on the regional air quality, environmental concerns
related to final ash and particulate disposal and scrubber water treatment are
significant. The proposed fluidized bed furnace at Blue Plains is estimated
to produce an average of 88 dry tons and a peak load of 168 dry tons of ash
per day that will require landfilling. The proposed long-term plan is to
dispose of the ash at the Lorton landfill.
Typically, the ash resulting from incinerating sludge is low in
moisture, free of pathogenic organisms and organic compounds. Any heavy
metals in the ash would be in an insoluble oxidized form and less mobile in
an alkaline environment.
In order to characterize the ash that would result from the incin-
eration of Blue Plains sludge, EPA Extraction Procedure (EP) toxicity tests
were performed by ES on sludge ash samples. Data on leachable metals from
the ash samples show that the metals concentrations in the Blue Plains sludge
ash were at least an order of magnitude lower than the maximum allowable
concentrations for toxic metals and would comply with the Resource Conserva-
tion Recovery Act regulations. The incinerator ash is expected to be clas-
sified as a non-hazardous waste. Tables 2.2 and 2.3 contain the results of
the EP toxicity tests. In some instances the ash from sludge incineration
4-25
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has been used as a soil conditioner. The proposed disposal by landfilling
should have negligible impact to the ecosystems in the area of Lorton due to
the nature of the resultant ash matter.
The liquid sidestream resulting from the scrubber system would be
treated by recycling the scrubber water back to the head of the plant's
wastewater treatment process. The recycle stream from the fluid bed system
under average loading conditions is estimated at 1.9 mgd, with a suspended
solids burden of 7,200 Ibs./day. This load is equivalent to an increase of
less than 3 mg/liter of suspended solids in a proposed 370 mgd plant influent
flow. (13)
4.3.3 Man-Made Environment Impacts
The incineration of sludge at Blue Plains would result in a
significant reduction of the mass and volume of solids. Transporting the
resultant ash to Lorton landfill would require significantly fewer trucks
when compared to transporting dewatered sludge. Fewer trucks and a reduced
number of trips to Lorton would favorably affect traffic flow patterns on
Interstate Highways 295 and 95 and on the Woodrow Wilson Memorial Drawbridge.
Although fewer trucks would be entering and leaving, effects upon noise
levels would be minimal. Although sludge incinerators create some noise when
in operation, much of the increased noise will be buffered by the traffic
traveling on the surrounding interstates.
The environmental considerations associated with the construction
of two 225 foot stacks on the Blue Plains site include the potential impact
on air traffic safety for aircraft landing and departing from Washington
National Airport and nearby military fields and the impact on the visual
aesthetics in the region around Blue Plains.
The proposed 225 feet height of the stacks follow EPA's good
engineering practice (GEP) guideline. (15) Before construction of the
stacks can proceed, the District must notify the Federal Aviation
Administration which will review the potential impacts on all aircraft
operations in the area. Federal aviation regulations (Part 77, Section
4-27
-------
77.13) state that any construction of more than 200 feet in height above the
ground level at its site requires notice and review by the FAA prior to the
start of construction. On November 2, 1987 the FAA issued a. Determination of
No Hazard to Air Navigation. The study conducted by FAA concluded that:
o The structures would not interfere with any airport traffic
patterns;
o The structures would not adversely impact any VFR or IFR
terminal procedure;
o The structures would not adversely impact any VFR or IFR
enroute procedure;
o The proposal would not impact any plans on file; and
o The structures would exceed obstruction standards and should
be marked and lighted.
The visual impact of the stacks will affect the aesthetic quality
of parks along the Potomac River including the Shepard Parkway Park to the
north, the Bald Eagle Hill Park located 2,000 feet to the east and Oxon Hill
Children's Farm located to the southeast of Blue Plains. The Daingerfield
Island Park, which is on the west shore of the Potomac River in Alexandria,
is a major recreational area and will be a part of a waterfront open space
system along the Potomac River. (1) Other areas that would be visually
affected would include Old Town in Alexandria and the Port America complex to
be located to the south of Blue Plains as well as from the White House and
Tidal Basin area. (See Plate 4.1 for the locations of those sites).
4.3.4 Air Pollution Control Systems
The proposed air pollution control systems for the Blue Plains
sludge incinerators include an afterburner, a Venturi scrubber, an afterco-
oler and a wet electrostatic precipitator. (See Figure 2.7). Table 4.11
4-28
-------
I WHITE HOUSE AND TIDAL BASIN AREA
2 SHEPARD PARKWAY PARK
3 OXON HILL CHILDREN'S FARM
4 DAINGERFIELD ISLAND PARK
5 OLD TOWN ALEXANDRIA
6 PORTAMERICA DEVELOPMENT
SITES VISUALLY IMPACTED
BY INCINERATOR STACKS
4-29
FIGURE 4-1
-------
TABLE 4.11
ESTIMATED REMOVAL EFFICIENCIES FOR POLLUTION DEVICES
PROPOSED FOR BLUE PLAINS INCINERATORS (1)
Pollutant
TSP
SOx
CO
VOC
NOx
Pb
As
Cu
Cd
Cr
(hexavalent)
Ni
Zn
Hg
Be
TCDD (dioxins
and furans)
HC1
H2S04
Control
Venturi Scrubber, ESP (2)
Venturi Scrubber, ESP
FBF, Afterburner (4)
FBF, Afterburner (4)
FBF, VS (4)
Venturi Scrubber, ESP
VS, ESP
VS, ESP
VS, ESP
VS, ESP
VS, ESP
VS, ESP
Venturi Scrubber, ESP
Venturi Scrubber, ESP
FBF, Afterburner (4)
Venturi Scrubber, ESP
VS, ESP
Estimated Removal Efficiency
99.9%
90.2%
NA (3)
NA (3)
16.7%
99.6%
90.0%
NA (5)
99.0%
98.7%
97.7%
NA (5)
78.6%
NA (5)
NA (3)
80%
82.3%
(1) Calculations based on uncontrolled and controlled emission factor data
obtained from Engineering-Science, Task 11-11, September, 1986 and
Task II-14G, December, 1986.
(2) Wet electrostatic precipitator.
(3) NA - not applicable. Removal dependent on incinerator combustion
efficiency. Controlled emissions will be negligible.
(4) Addition of afterburner increases retention time of gases, assures
complete combustion, destroys remaining organics.
(5) Uncontrolled emission rate unavailable to estimate removal efficiency.
4-30
-------
summarizes the removal efficiencies for the proposed pollution control
devices.
With proper operation, the FBF could maintain a high combustion
efficiency which would reduce CO production to negligible amounts and destroy
any toxic organic compounds that may be present. Proper operation would also
help to control NOX and VOCs. The addition of an afterburner to the inciner-
ation process would assure complete combustion and increase the destruction
of VOCs and organics.
The proposed Venturi scrubber operates on the principle that as gas
enters a contracted throat area followed by a expanded section, high turbu-
lence is created. The water in the combustion gases condenses in the con-
traction and water is injected at the throat. This water atomizes and is
mixed with the combustion gases by the turbulence. Particles are collected
on the atomized water droplets using interception, impingement, and gravita-
tional mechanisms. The Venturi scrubber and aftercooler will remove approxi-
mately 99 percent of the particulates by weight dependent on the particulate
size. It will also remove some gaseous pollutants such as S02, hydrogen
chloride (HC1), 0*2804, NOX and oxidized mercury. Because the melting
temperature of Be is high, it is unlikely to volatilize and will be removed
much the same as the particulates. The Venturi scrubber and subsequent
aftercooler would cool the combustion gases, allowing condensation of the
trace metals into fine particles. These particles will tend to deposit on
small flyash particles. Finally, the cooling will reduce the volume of
combustion gas moving through the wet electrostatic precipitator (ESP).
A wet ESP operates by charging the suspended liquid droplets and
particles in the combustion gases with a positive electrode and allowing
these charged particles and droplets to migrate toward a negative potential
collector plate. The liquid droplets collect on the plates and form a water
film which washes the plates clean.
Based on data from ES the proposed Blue Plains wet ESP system would
collect 90 percent of the remaining TSP and some S02. Hydrogen chloride and
sulfuric acid (H2S04) mist removal could be increased to 80 percent. Removal
4-31
-------
of 90 percent or more of the trace metals Pb, Cr, Cd, Nl, As, Zn, and Cu
would be expected, along with over 75 percent removal of Hg. The ESP would
reduce the water In the combustion gases to help suppress the steam plume.
The steam plume is further reduced by the reheat chamber before the cleaned
combustion gases are emitted.
4-32
-------
4.4 LAND APPLICATION
Land application of sewage sludge involves the utilization of sludge as
a source of fertilizer and as a soil conditioner in primarily agricultural
areas. Loading rates are based upon nutrient requirements of given crops and
the life expectancy of a site is dependent upon the metals content of the
sludge. Adherence to the limits set by state regulations is an effective
mitigative measure in avoiding such impacts as groundwater contamination,
phytotoxicity and sickness in animals and humans. However, land application
programs have unavoidable impacts on the transportation system, surrounding
land use and may involve the generation of malodors. These impacts need to
be considered along with the value of the sludge as a fertilizer and the cost
of operating a land application system when evaluating the suitability of
land application as part of the total sludge management program.
4.4.1 Natural Environmental Impacts
4.4.1.1 Nutrients
The impacts of land application of municipal sludge on the natural
environment are dependent upon sludge quality and specific site character-
istics. Typically, prior to land spreading of sludge, at least three
composite samples from the treatment plant should be analyzed for total
nitrogen, ammonia as nitrogen, phosphorus, potassium, magnesium, manganese,
iron, zinc, copper, nickel, lead, cadmium, chromium, mercury, PCB's, percent-
age total solids and pH in order to determine the optimal loading rate.
Table 4.12 shows the concentrations of these constituents in Blue Plains
sludge with the exception of manganese, mercury and PCB's. Manganese is a
trace metal common in sludges is necessary for proper plant growth and
influences uptake of various heavy metals, but is not regulated in Maryland
or Virginia. Maryland and Virginia both regulate for various items including
mercury and PCB's by prohibiting land application of sludges which contain
levels of these elements. The remaining constituents are controlled in these
state's regulations to establish sludge suitability for land application and
to determine proper loading rates and site life expectancy.
4-33
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TABLE 4.12
INDIVIDUAL SLUDGE STREAM CHARACTERIZATION SUMMARY
JANUARY - MAY 1986 DATA PERIOD (1)
Dewatered
Parameter
Nitrogen, Total
Ammonium Nitrogen
Phosphorus , Total
Potassium
Calcium
CaC03 Equiv.
Magnesium
Iron
Cadmium
Chromium
Copper
Lead
Nickel
Zinc
Average
N %
NH4-N %
P %
K %
Ca %
%
Mg %
Fe %
Cd ppm
Cr ppm
Cu ppm
Pb ppm
Ni ppm
Zn ppm
Total Volatile Solids %
Soluble Salts
Moisture
pH
%
%
3
0
1
0
10
26
0
8
6
121
267
191
40
408
41
3
81
11
.17
.056
.42
.079
.478
.83
.217
.049
.5
.98
.3
.7
.64
.6
.02
.44
.47
.80
Raw Sludge
Minimum
0.
0.
0.
0.
5.
15.
0.
6.
4.
94
190
100
21
300
37
1.
77.
11
97
0034
50
04
82
54
121
30
1
07
81
Maximum
4.65
0.12
1.91
0.142
12.14
31.15
0.301
11.57
9.5
141
440
256
59.5
600
45.3
6.3
85.34
12.82
Dewatered Digested Sludge
Average
3
0
1
0
11
28
0
7
5
109
279
171
38
428
41
4
85
11
.97
.048
.36
.085
.15
.54
.231
.92
.64
.50
.30
.5
.1
.4
.51
.38
.21
.65
Minimum
1.
0.
0.
0.
6.
17.
0.
4.
3.
69.
150.
104
23
264
35.
1.
78.
10.
60
0044
091
031
36
91
114
00
3
5
0
68
31
48
15
Maximum
7.17
0.114
1.3
0.2
12.92
35.32
0.492
12.8
8.45
200
524
262
57
655
46.07
7.40
84.67
12.17
(1) Based on monthly sludge analyses provided by the Bureau of Wastewater
Treatment, District of Columbia.
4-34
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Potential for overloading the soil with nutrients and heavy metals
has led to current methodologies for determining site and sludge suitability
for land application. Adherence to these methodologies will minimize the
potential impacts of heavy metal concentrations in soil, phytotoxity, and
disease from ingestion of sludge amended crops.
Loading rates for municipal sludges like that from Blue Plains are
based on the amount of nitrogen necessary to produce maximum yields of a
given crop. Exceeding this rate will produce an excess of nitrogen which may
cause adverse effects on some crops such as lodging of small grains and
leaching of nitrates into the groundwater. Table 4.13 lists the nitrogen
requirements for various yields of selected crops grown in the Maryland-
Virginia region.
Nitrogen runoff, the movement of nitrogen from land surfaces to
surface water bodies, is one type of nonpoint source pollution currently of
great concern to the Chesapeake Bay area. This form of pollution is highly
variable because it depends on precipitation and local conditions. Research
has shown that the risk of inorganic nitrogen runoff from agricultural fields
can be reduced if crops are fertilized with sludge rather than nitrogen
fertilizer. A recent Clemson University study (Pasture Runoff Water Quality
from Application of Inorganic and Organic Nitrogen Sources - McLeod & Hogg,
1984) compared ammonia nitrogen (NH4-N) and nitrate nitrogen (N03-N) runoff
from fescue pastures that were fertilized with either municipal sewage sludge
or a common inorganic nitrogen fertilizer (NH4 NC>3). The sewage sludge plots
had lower rates of nitrogen runoff than the fertilizer plots. This reduced
transport may be attributed to high organic versus inorganic fractions of
nitrogen which are contained in sludge. Organic nitrogen tends to hold to
soil particles and not to move with runoff water. Inorganic nitrogen, both
NH3 and N03, is highly mobile and will move freely with runoff water.
An issue not considered by the above referenced study is that
organic nitrogen can contribute to nitrogen runoff, if sediment is being
carried by the runoff water. However, guidelines and regulations guard
against this. This is commonly called erosion and occurs most frequently in
areas with little vegetative cover, such as corn fields. Land application
4-35
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operators often inject sludge below the soil surface to decrease surface
runoff of organic nitrogen. Also there is some evidence that long-term
applications of sewage sludge can improve soil structure and decrease soil
erodibility.
An estimated maximum loading rate for Blue Plains sludge can be
calculated by dividing crop nitrogen requirements by the amount of nitrogen
present in the sludge which is available for crop uptake (estimated here at
40 percent of total N) . For example:
Expected Corn Yield - 125 bu/ac
Nitrogen Requirement - 155 lbs/ac(l)
N content of Sludge - 70 lbs/ton(2)
155 Ibs/acre
70 Ibs/ton (40% avail.) -5.5 tons/acre
(1) Based on Maryland sludge management regulations, Table 4.14
(2) Taken from Table 4.12, D.C. sludge stream characterization
The actual method for calculating nitrogen loading rates varies
with the regulations of the state receiving the sludge. This loading rate
should then be compared to those calculated for the other constituents tested
in order to determine the limiting factor and life expectancy of the site.
Excess phosphorus in surface waters has been a key factor contribut-
ing to the eutrophication of streams and lakes throughout the U.S. The major
source is agricultural land runoff burdened with excess phosphorus from
fertilizers, manure and sewage sludges. For this reason, estimated phos-
phorus requirements for crops should be considered along with nitrogen
requirements. Table 4.12 shows that sludge from Blue Plains typically has
less than one half the amount of phosphorus as compared to nitrogen (27.8
Ibs/ton P vs. 71.4 Ibs/ton N). In this case, nitrogen is the limiting
factor to be used in determining loading rates and phosphorus poses no
long-term or short-term threat at levels found in the sludge. In addition,
as noted above, there is the reduced erosion potential from soils treated
with sludge.
4-36
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TABLE 4.13
NITROGEN REQUIREMENTS FOR SELECTED CROP YIELDS
Crop
Corn Grain
Wheat
Oats
Soybeans
Yield
100 bu/ac
115
120
125
125
40 bu/ac
45-60
70
55 bu/ac
55
35 bu/ac
40
45
50
60
Lbs N/Acre
120
140
145
155
add 15 Ibs N for each 10 bu above 125
60
add 1 Ib N for each bu over 40
95
55
add 1 Ib N for each bu over 55
140
180
195
210
240
Source: Maryland Sewage Sludge Management Regulations COMAR 10.17.10.
4-37
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4.4.1.2 Heavy Metal
The actual calculation of loading rates and site life expectancies
is highly site specific due to the variability in soil and sludge. Sites
which are used in successive years must be retested to determine the movement
of nutrients and metals in the soil-plant environment. Maximum metal
accumulations allowed in Maryland and Virginia are listed in Table 4.14.
The U.S. EPA, U.S. Food and Drug Administration, and the U.S.
Department of Agriculture have adopted a Statement of Federal Policy and
Guidance for the Land Application of Municipal Sewage Sludge for the
Production of Fruits and Vegetables. This policy sets forth technical
guidance on lands that will subsequently be utilized for fruit and vegetable
crop production.
TABLE 4.14
MAXIMUM METAL ACCUMULATIONS
FOR SLUDGE AMENDED SOILS
Metal
Maryland
Soil Cation Exchange Capacity
Less Than 5 5 or Greater
Ibs/ac Ibs/ac
Virginia
Soil Cation Exchange Capacity
Less Than 5 5 to 15 15 or Greater
Ibs/ac Ibs/ac Ibs/ac
Cadmium
Copper
Nickel
Lead
Zinc
4.4
125
125
500
250
8.9
250
250
1,000
500
2.22
111
44
445
222
4.45
222
89
890
445
8.9
445
178
1,780
890
Source: Maryland Sewage Sludge Management Regulations.
Virginia Sewerage Regulations.
Once the loading rate has been chosen, the cumulative addition of
heavy metals to levels causing phytotoxicity, animal or human health problems
must be restricted. For this reason, the life expectancy of a site is calcu-
lated based upon regulated maximum heavy metal concentrations. These factors
4-38
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are calculated for the Blue Plains sludge being land applied in typical
Maryland soils.
Lead is a nonessential element for plants and animals and acts as a
cumulative poison in mammals. There has been relatively little concern about
lead contamination of soils in the past because of the relative insolubility
of adsorbed and precipitated lead in soils. Current regulatory action
reflects an increased concern dealing with lead levels now found in the
environment. Therefore, the levels of lead introduced by a land application
system are a potential health impact. Lead concentration in plants is gen-
erally low, although lead may reach higher accumulations in roots and contam-
ination of root crops may be of concern. Translocation of this lead from the
roots to plant tops may take place if background phosphate levels are low.
Additional concerns about crops grown for human consumption include contami-
nation through contact with soil particulates and increased soil accumulation
as a result of aerial contamination from leaded gasoline. An increase in
vehicular traffic for a land application system or site location adjacent to
a major thoroughfare may therefore be an additional contributor to the threat
of high lead concentrations in soil or plants.
Zinc is the most abundant and often the most valuable heavy metal
occurring in sewage sludge with respect to plant, animal and human nutrition.
In terms of toxicity, excessive zinc levels can be more detrimental to plants
by contributing to chlorosis (marked by yellowing) than to animals or humans
which can accept much higher levels before reaching toxicity. The mobility
of zinc in soil is influenced by soil pH, organic matter and texture although
it is unlikely to leach deep enough to cause groundwater contamination.
Chromium, in its trivalent form (CR III), is not required for plant
growth but is essential for human nutrition. On the other hand, hexavalent
chromium, or chromate, is toxic to aquatic life, microorganisms, higher
plants, and animals and is a suspected human carcinogen. Concern with toxic
chromium levels in soils and drainage to groundwater is limited to hexavalent
chromium since it constitutes a risk to humans. Considerable research is
taking place to determine the extent to which trivalent chromium may oxidize
into the toxic hexavalent form by contact with manganese oxides present in
4-39
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the soil. This process can create the more mobile and toxic hexavalent
chromium anion which can leach into groundwater supplies. The amount of
chromium in Blue Plains sludge is comparably low with respect to more
industrially related sludges. However, the monitoring process should include
testing of chromium III and VI in order to determine the oxidation rate and
the potential for groundwater contamination.
Copper is essential for plant growth but can also be toxic. The
level of difference in concentrations between a copper deficiency or toxic
condition is relatively narrow. Thus, determination of proper loading rates
is difficult. In addition, the interaction between soil and plants with
respect to copper is very complex. However, several observations can be made
regarding the impacts of copper content in municipal sludge. First of all,
copper content of roots is generally several times higher than in plant stems
and leaves and phytotoxicity is often manifested through a reduction in root
activity. Secondly, copper interactions are tied to the level of organic
matter in the soil and therefore the addition of low copper sludge should
provide protection for plants. On the other hand, as soil pH decreases,
availability of copper increases along with the threat of phytotoxicity.
Finally, copper does not move rapidly through the soil by leaching unless
found in excessive amounts. It is therefore less likely to cause contamina-
tion of water supplies but more likely to have residual effects on plants.
Absorption and retention of nickel by animals and humans is gen-
erally low and the threat of toxicity is therefore unlikely. However, nickel
is more mobile in acid soils and plants in these soils have a high uptake
rate which may cause phytotoxicity before it reaches levels that could affect
animals or humans. Due to nickel's high toxicity to plants, it is one of the
metals found in sludges most likely to cause reductions in crop yields.
Cumulative limits are generally held to no more than a few times the back-
ground level.
Cadmium is the trace metal in sludges which produces the greatest
concern for human health. Concentrations of cadmium in levels greater than
three pounds per acre in silt loam soils (level varies for other soil types)
4-40
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have been shown to cause accumulations in the liver and kidneys of laboratory
animals. In fact, the relatively high soil and plant concentrations of
cadmium which are toxic to plants are irrelevant when considering loading
levels which may create toxic conditions for animals and humans. There is an
additional concern of adverse impacts on soil microorganisms and inverte-
brates from cadmium additions. Although no toxic effect on earthworms has
been found, toxicity with respect to microorganisms, invertebrates, higher
animals and humans may indeed occur if levels exceed those recommended by
current regulations.
The potential for environmental contamination through land applica-
tion of Blue Plains sludge is dependent upon the levels of the metals found
in. the sludge and the procedures used in the land application process.
Nitrogen overloading from the sludge is unlikely if loading rates are based
on state regulations and crop requirements. Groundwater and crop contamina-
tion is mitigated by matching the amount of available nitrogen to the amount
necessary for maximum yields. Lead contamination is also unlikely due to the
low level found in Blue Plains sludge. However, other localized sources,
may contribute to lead levels in soil and plants and may increase the poten-
tial for reaching toxic levels. Zinc and nickel both cause phytotoxicity
well before reaching levels which are hazardous to animals and are found in
low concentrations in Blue Plains sludge. Therefore, these metals are
unlikely to cause environmental contamination if loaded at properly calcu-
lated rates. The amount of chromium found in Blue Plains sludge is rela-
tively low in comparison to other metals. Copper is calculated to be the
limiting factor with, respect to site life expectancy and is therefore likely
to be the first metal to reach toxic levels. Adherence to loading rates set
by state regulations should keep copper levels within an acceptable range.
Cadmium is a highly toxic element and is strictly regulated to reduce the
threat to human health. Blue Plains sludge typically contains from 3.3 to
9.5 ppm of cadmium which is well within the Maryland Class I limit of 25 ppm.
Blue Plains sludge is therefore suited for land application if loading rates
are kept below regulatory and toxic limits.
4-41
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4.4.1.3 Pathogens
In addition to concern over the potential overloading of soil with
nutrients and heavy metals, land application of sludge carries the threat of
possible pathogen transfer since pathogens may survive treatment processes.
The disease-causing agents commonly found in municipal sludges are listed in
Table 4.15. Pathogen transfer is a concern in the land application of
municipal sewage sludge. EPA has set forth regulations that establish
criteria for municipal sewage sludge disposal practices. These regulations
provide for Processes to Significantly Reduce Pathogens (PSRP) and Processes
to Further Reduce Pathogens (PFRP). As stated, these processes are to be
utilized by municipal wastewater facilities to reduce pathogens in the sludge
and therefore reduce the potential for transfer during the land application
process.
The survival of pathogens in soil is highly variable and may extend
to as much as 12-14 years for the eggs of parasites and spore-forming
bacteria. The actual survival time is dependent on such factors as moisture
availability, temperature and soil pH.
Most bacteria and parasite ova are immobilized in the soil through
physical and chemical straining. Therefore, the greatest threat to water sup-
plies is through runoff into surface streams and ponds. Virus removal is
primarily through adsorption on soil, although some removal may take place
through physical sieving. Since mechanical removal of pathogens is the
primary method of pathogen reduction, soil texture is a major factor in pre-
dicting and preventing pathogen transport to groundwater supplies. Areas
with a soil cover of 20 inches or less and highly fractured bedrock should be
avoided in a land application program in order to further reduce the threat
of toxicity from pathogen transfer into the groundwater.
4-42
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TABLE 4.15
PATHOGENS FOUND IN SLUDGES
AND RESULTANT DISEASES
Type of Organism
Bacteria
Viruses
Protozoa
Nematodes
Cestodes
Pathogen
Salmonella
Mycobacterium
Shigella
Escherichia coli
Leptospira
Enteroviruses
Adenoviruses
Hepatitus virus
Toxoplasma
Giardia
As caris
Toxacara
Taenia
Disease
Typhoid fever, gastroenteritis
Tuberculosis
Dysentery
Gastroenteritis
Leptospirosis
Gastroenteritis, polio
Acute respiratory disease
Hepatitis
Toxoplasmosis
Gastroenteritis
Ascaritis pneumonitis
Visceral larva migrans
Cysticerocis
Source: Criteria and Recommendations for Land Application of Sludges in the
Northeast, 1984.
4-43
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Land application of sludge for agricultural use represents the
useage of a potentially valuable resource rather than the disposal of a waste
product. Table 2.7 indicates that sludge from Blue Plains has an approximate
fertilizer value of $42 to $46 per dry ton of sludge. This represents a
total value of over $25,000 if spread over 100 acres at a rate of 5.5 dry
tons per acre. This value can be further enhanced through the inclusion of
the value of the increased level of crop production. Therefore, the
potential adverse impacts of nutrient, metal and pathogen overloading caused
by improper operating procedures must be weighed against the beneficial
utilization of a resource. These have been taken into consideration by the
regulatory agencies in the preparation of regulations and guidelines
regarding land application.
Another area of potential impacts from a land application program
involves off-site storage of sludge in temporary facilities. Both Maryland
and Virginia regulate the design and operation of storage lagoons in order to
avoid many of these potential impacts.
Specific areas of concern include many of those items previously
discussed in this section such as leachate control, generation of malodors,
the potential for spills and metal accumulation in soils and pathogen
transfer into the local environment. Leachate and excessive accumulations of
heavy metals could occur in the event of accidental spillage or leakage from
the lagoon. The impacts of these occurrences has been discussed previously
in this section. Generation of unpleasant odors is an unavoidable impact due
to the amount of sludge in contact with the air. The most effective mitiga-
tive measures are pretreatment and timely incorporation of sludge into the
soil using modern equipment that discs or injects the sludge beneath the
surface. Pathogen transfer is made possible through aerosols and direct
contact with the sludge. Once again, these impacts are mitigated through
pathogen reduction in pretreatment and rapid incorporation into the soil.
4-44
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4.4.2 Impacts on the Man-Made Environment
In addition to the potential impacts on the natural environment, a
land application program may influence the man-made environment through the
existing transportation system and existing land use patterns.
A major concern in an agricultural land application program is the
transportation of dewatered sludge from the treatment plant to the farm. In
the case of Blue Plains, sludge must be transported to available land in
Maryland and Virginia. If the sludge is dewatered to 21 percent solids, the
transport of 200 dry tons plus 50 dry tons of post lime, or 1,100 cubic yards
per day would require a minimum of 37 to 44 truck trips per day (25-30 cubic
yard/truck). Specialized agricultural vehicles are also required to properly
apply the sludge. The overall impact on the transportation system is related
to the availability and location of land application sites as well as the
loading capacity of the individual farms.
In addition to the transportation impacts in rural areas, the land
use of these areas may also be restricted by land application of sludge.
Legislation in Maryland and Virginia limits the types of crops which can be
grown in sludge amended soils, determines the areas suitable for land appli-
cation and establishes buffer areas in which sludge may not be applied.
According to information from the Virginia Department of Health, the State
strongly encourages a one-time land application of agricultural sites. The
State requires soil testing and groundwater monitoring at sites where an
application is repeated within a three year period. These factors may
increase the amount of necessary acreage and create the potential for con-
flicts with areas of non-conforming land use. Future land use may also be
affected through limits placed on sludge amended areas, especially those
areas dedicated for sludge disposal.
4-45
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4.5 IN-VESSEL COMPOSTING
This section will define the potential impacts of in-vessel composting
an average of 200 dry tons/day of Blue Plains sludge. Sludge compost is a
stable soil conditioner which is considered to be free of pathogenic organ-
isms and weed seeds and lacking in objectionable odors. The nutrient value
of the final product is low, with a typical Blue Plains Nitrogen-Phosphate-
Potassium value of only 1-2-0.1. However, the texture and high organic
matter content of sludge compost increases the air and water holding capacity
of most soils, improves the structure of clay soils, decreases erosion
potential, improves soil workability, and increases the metal holding ability
(cation exchange capacity) of the soil. The use of compost by the general
public necessitates that adequate monitoring of the product take place to
avoid potential adverse impacts and assure the long-term marketability of the
final product.
4.5.1 Natural Environmental Impacts
Many of the impacts of a sludge composting program are similar to
those discussed under the land application alternative due to the similar use
of the final product. However, the composting process transforms the sludge
so that several of the impacts previously mentioned are mitigated or altered.
These impacts include metal and nutrient loading in soil and vegetation,
pathogen transfer, leachate and condensate production, odors and related
impacts on the man-made environment.
The heavy metal concentrations in compost from Blue Plains and Site
II are relatively low due to the low metals content of the sludge. Table
4.16, Comparison of Sludge and Compost Constituents, shows the nutrient,
metal and pathogen content of dewatered raw and digested sludge and compost
from Blue Plains and Site II. The slightly lower metal concentrations of the
compost may be attributed to absorption onto the bulking material.
In addition to the lower heavy metal concentrations of compost, the
stabilized organic matter binds the metals more tightly through an increased
cation exchange capacity. This indicates that the potential impact of metals
4-46
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TABLE 4.16
COMPARISON OF SLUDGE AND COMPOST CONSTITUENTS
Parameter
Total N
Total P
Potassium
Solids
pH
Cadmium
Copper
Iron (4)
Mercury
Nickel
Zinc
Lead
Blue Plains
Dewatered Digested
3.17%
1.42
.08
20.00
11.80
6 . 50 ppm
267.30
80,490.00
40.64
408.60
191.70
Blue Plains
Sludged) Comoost(2)
1.32%
1.50
.07
58.31
7.28
5 . 40 ppm
365.00
65,000.00
38.80
468.70
75.10
Site II CompostO)
1.02%
.43 (phosphate only)
.12
50.80
7.30
4 . 60 ppm
90.00
22,596.00
1.20
15.50
147.10
227.10
(1) January - May 1986 average monthly values - See Table 2.6 in Chapter 2.
(2) June, August and September 1986 biweekly average values.
(3) 1985 average monthly values.
(4) Ferric (iron) chloride is added in the wastewater treatment systems for
phosphorus removal .
All values are based on dry weight.
reaching the groundwater from compost application is unlikely. These metals
may still be taken up by some plants and application on vegetable gardens
should be done with great care and avoided when possible.
In order to assure long-term marketability, a consistent product
quality and low metal levels must be maintained within regulatory constraints
established by Maryland and Virginia. Figure 4.2 shows that the metal
content of compost from Blue Plains and MCCF is well below the metals levels
established by the Maryland Environmental Service.
4-47
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c
o
•r-l
IX
Figure 4.2
Comparison of Compost Metal Concentrations
250 -,
200 4
150 J
100 1
50 H
Cadmium
Copper* Mercury
Nickel
Zinc*
Lead*
| ] MES Regulatory Limits
Compro (MCCF) (1965 avg.)
Blue Plains Compost (6/86, 8/86, 9/86)
* Values expressed in tenths of actual value.
4-48
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The N-P-K ratio of 1-2-0.1, illustrates the fact that compost has
limited fertilizer value and that its use is primarily as a soil conditioner.
There is little threat of significant nitrate leaching or nutrient runoff
problems from the use of sludge compost. In addition, compost nitrogen is a
slow release form rather than the rapid release form commonly found in
dewatered sludge.
Composting is listed by EPA as a process to further reduce patho-
gens (PFRP) which indicates that the final product is safe for distribution
to the general public. Although composting typically destroys pathogens,
there still exists the potential threat of survival of resistant primary and
secondary pathogens (those affecting healthy and susceptible people, respec-
tively) in the final product as the result of improper process operation and
insufficient volatile solids destruction (Reference 20). The increased
process control achieved through in-vessel composting should minimize these
problems.
One of the major concerns at a composting site is the control of
leachate, condensate and runoff in order to mitigate potential water quality
impacts. The amount of condensate and leachate generated during composting
is related to the moisture content of the sludge and bulking material and
other ambient conditions. Approximately 2,000 to 6,000 gallons per day
(10-30 gpd/dry ton) would typically be generated in an aerated static pile
composting operation with an input of 200 DTPD. Levels found in an in-vessel
system would be similar, although system design allows for easier capture of
those liquids. Most precipitation falling on a compost pile is absorbed or
evaporated and runoff levels are typically low. If these liquids are allowed
to collect on the surface, odors, or ice in winter may result. Inadequate
collection systems may also result in ground and surface water contamination.
In-vessel composting permits liquid capture and recycling into the wastewater
treatment process. Water input from precipitation is not a factor in the
in-vessel composting system. Table 4.17, Analysis of Condensate, Leachate
and Runoff from a Composting Operation, indicates typical contaminant levels
found in these liquids.
4-49
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TABLE 4.17
ANALYSIS OF CONDENSATE, LEACHATE AND RUNOFF
FROM A COMPOSTING OPERATION
Constituent
BOD
COD
P04-P
N03-N
Organic N
NH3-N
TKN
CaC03
(Alkalinity)
PH
Condensate
2,000 mg/1
4,050
1.87
.73
139
1,140
1,279
4,030
7.7
Leachate
2,070 mg/1
12,400
2.13
.46
655
905
1,560
2,930
7.7
Runoff (I)
91 mg/1
61.3
.31
.16
58
115
173
361
8.2
(1) Runoff characteristics are a function of rainfall rate and volume.
Source: Composting of Municipal Wastewater Sludges, U.S. EPA 625/4-85/014.
4-50
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Perhaps the most readily recognized impact of sludge composting is
the potential for the production of malodors. These odors tend to predomi-
nate at facilities where sludge piles are left exposed before mixing and
where composting is left incomplete. One of the most common odor causing
problems is inadequate aeration and anaerobic conditions within the compost.
The best method for controlling potential odor generation is by maintaining a
proper oxygen supply, adequate temperatures and by keeping the site clean.
In the case of the proposed in-vessel system, off-gases would be captured and
deodorized in a scrubber system and temperature and oxygen levels would be
monitored by microprocessors.
Odor and noise control are major concerns of an in-vessel compost-
ing facility. The manufacturers of the various in-vessel reactors have
addressed the control of these concerns with their specific designs.
Generally, the reactors are contained within a building or system enclosure
which reduces noise levels and assures odorous process exhaust air is col-
lected for treatment.
Typically, all exhaust air from a reactor building is treated by a
multi-stage odor control system consisting of:
o Exhaust air fan system
o Heat exchanger for cooling
o Two-stage wet scrubber chemical reactor for particulate
removal and chemical treatment of odorous compounds
This control system is intended to assure treatment of all odorous
air contained within the building prior to discharge outside of the building.
4.5.2 Man-Made Environmental Impacts
Most of the potential impacts on the man-made environment are
directly related to the large volume of compost that would be produced if all
of the sludge from Blue Plains were to be composted. This would lead to a
4-51
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total production of approximately 1,300 cubic yards/day of finished compost.
An estimated 600 cubic yards/day of the total production would result from
the 200 DTPD of sludge. While the 600 cubic yard volume is less than the
current volume of sludge transported off-site, the total volume may poten-
tially impact the transportation systems in the area.
Transportation of 1,300 cubic yards/day of compost requires a
minimum of 44-52 trucks (25 and 30 cubic yard capacities) if the compost is
delivered in large volumes to only a few buyers. In comparison, an estimated
1,000 cubic yards/day of dewatered sludge are currently being transported
off-site under the interim management program. It is more likely that the
transportation of the final product will require a larger number of smaller
capacity vehicles to reach all markets. However, this is not the total
traffic volume because the transportation requirements for the bulking agent
must also be taken into account. Therefore, the composting alternative has
the largest potential impact of any of the alternatives on the existing
transportation system because of the transport of both the compost and a
bulking agent.
The total number of vehicles and routes taken in the composting
alternative are related to the marketability of the final product. Compost
from Site II has been highly marketable within the region while compost from
Blue Plains has been more difficult to market. The proposed composting of
all of the Blue Plains sludge would have to overcome this problem and expand
the existing market area in order to dispose of the increased quantity of
compost. The supply of compost resulting from the use of a full composting
alternative will have a major impact on the regional supply when production
from other facilities is accounted for. A preliminary market report prepared
for the District in 1985 stated that the initial annual market potential
demand was 277,400 cubic yards, with an estimated increase to 1,350,000 cubic
yards within ten years. In addition, the compost market roughly corresponds
to the growing season which takes place in the warmer months, when traffic
volumes are at their peaks. Successful marketing of compost year-round will
be required in order to decrease the impact of this alternative during times
of peak activity.
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Section 2.5, Composting and Product Use, indicates that an esti-
mated 24 acres of land may be required for in-vessel composting of an average
of 346 DTPD of sludge at Blue Plains. Available land at the Blue Plains site
is finite and a majority of the remaining area is committed to treatment
basin expansion (e.g. swing sedimentation basins) to improve treatment
capabilities. The use of the remaining site area, even with a. specific site
minimizing design approach, for a full composting option must consider the
future inability to expand the wastewater treatment processes due to site
constraints. Additional land may therefore have to be acquired to handle
this volume of compost based on the final system design.
Compost has a potential to catch fire during the composting or
curing process if the material becomes too dry and internal temperatures
approach peak levels. The threat of fire can be minimized through adequate
mixing, aeration and prompt marketing of the finished product. In-vessel
composting should have a lessened potential for igniting through closer
monitoring of the product throughout the composting process. Proper on-site
controls and adequate fire protection should be maintained at all times to
reduce the potential for a serious fire.
The aesthetic aspects of in-vessel composting are highly sub-
jective. However, the removal of the aerated static piles at Blue Plains and
subsequent replacement with an enclosed unit should be seen as an aesthetic
improvement. Improved quality control and odor control will add to the
aesthetic advantages of this alternative.
4.5.3 Health Risk Assessment
The health risks associated with composting have been evaluated and
assessed periodically since the early Beltsville aerated static pile
composting work. A study was conducted between 1979 and 1981 at wastewater
sludge composting facilities in Camden, N.J., Philadelphia, PA, Beltsville,
MD, and Washington, D.C. to evaluate operator exposure to bacteria, fungi,
and microbial products. The investigation used clinical, microbiological and
immunological methods to evaluate the health effects related to composting
dewatered sludge.
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A potential risk to workers at wastewater sludge composting sites
may occur because of possible exposure to Aspergillus Fumigatus spores. They
are pathogenic, through inhalation of dust generated during composting
operations. No consistent increase in antibody to A. Fumigatus was detected
in some compost workers. However, throat and nasal cultures indicated
exposure to the fungus A. Fumigatus and one worker had a serious ear
infection caused by exposure to Aspergillus Niger. Physical examinations of
exposed workers found they had an excess of nasal, ear, and skin disorders
compared to non-exposed workers. Illness symptoms of burning eyes and skin
irritation were also reported more often in exposed workers and there was
some indication of low-grade inflammatory responses.
Appropriate work practices including facilities for daily showers and
separation of clothing used on the job and after work has been recommended,
along with continued exposed-worker studies. (54, 55).
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4.6 DRYING AND PRODUCT USE
The environmental considerations associated with heat drying sludge
include impacts from the moist gas stream that would be discharged into the
atmosphere, the liquid sidestream from scrubber units and particulate emis-
sions that may result from the storage and transport of the dried sludge
pellets. The final sludge pellets resulting from the drying process would be
transported by truck to permitted land application sites. Therefore, the
transportation systems in the vicinity of Blue Plains would be affected.
Storage of the pellets would be in enclosed silos constructed at the Blue
Plains site and at the land application sites.
The process of exposing dewatered sludge to hot gases will result in the
release of moist air due to evaporation of water from the sludge. The temper-
atures in a drying unit typically reach 121°C (250*F) and will result in the
removal of volatile organic compounds (VOCs), the destruction of disease-
causing organisms and the stabilization of the sludge to a point where
further decomposition will not occur. The dried sludge product is a solid
that contains about 10 percent moisture and most of the organic and nutrient
value found in dewatered sludge.
4.6.1 Natural Environmental Impacts
Heat drying sludge at Blue Plains would impact the available
on-site storage area, the regional ambient air quality and the need for
permitted land application sites for the dried sludge product.
4.6.1.1 Air Quality
The impact on the ambient air quality in the region around Blue
Plains is linked to the pollutants emitted in the gases exhausted from the
dryer. The sources of pollutants would be from fuels burned in the furnace,
the sludge feed, the remining volatile organic compounds after the drying
process and the hot moist air that causes a plume in the exhaust.
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The combustion fuels considered were fuel oil, natural gas or
digester gas. The pollutants that result from the combustion of fuel would
be transported through the rotary dryer and discharged into the atmosphere
along with pollutants emitted from the drying process.
The region surrounding the Blue Plains facility is classified as a
nonattainment area for CO and 03. Volatile organic compounds (VOCs) that are
not removed by the pretreatment process will contribute to ozone formation.
The control of VOCs will rest primarily within the rotary heat dryer and the
average temperature levels inside. Temperatures reaching 250°F should be
high enough to remove any VOCs remaining in the sludge after pretreatment
processes. The installation of an afterburner and a wet scrubber unit would
reduce S02, NOx, VOC and CO emissions.
Particulate emissions due to dust particles from the dried sludge
are an environmental concern from the standpoint of air quality. Dust
particles may result during the storage and transport of the dried sludge
product. Control of dust due to these operations would be difficult. The
pelletization of the final dried sludge product reduces dust emissions.
Particles escaping with the exhaust gas would be removed by the scrubber
unit.
4.6.1.2 Soil and Surface Waters
The impacts of the heat drying process on soil and the surface
waters near Blue Plains and near land application sites depend on the quality
of the sludge, the management of the liquid sidestream, and the topography
and soil characteristics of the land application sites. The impacts on the
Blue Plains site would result from removal and treatment of the liquid side-
stream from the scrubber unit and from any accidental leachate rewetting of
the product. Treatment of the sidestream by recycling it back to the head of
the plant will reduce the potential for pollution to the nearby surface
waters. Leachate collection systems will also be necessary to avoid pollu-
tion of surface waters.
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The removal of dried sludge pellets to storage silos, and the trans-
port of the pellets from Blue Plains to the site where the product will be
land applied may create environmental problems if the pellets are rewetted.
The addition of moisture will create an environment for bacterial regrowth
and decomposition. Rewetting will also contribute to odor problems due to
decomposition. Proper moisture-free storage areas on-site, in transit and at
application sites are necessary in order to control rewetting problems.
The recommended use for the heat dried sludge pellet is land
application on agricultural fields. The pellet is primarily a soil con-
ditioner with a fertilizer value comparable to that of dewatered sludge.
It will be assumed in this assessment that the impact of land applying the
pellet will be similar to that of land applying dewatered sludge. Section
4.4 contains an assessment of the environmental impacts associated with the
land application of Blue Plains sludge. Land application is regulated by
federal, state and local agencies.
The chemical content of sludge feed determines what components will
be found in the final sludge product. Numerous analyses have been performed
on Blue Plains sludge to characterize the components and the concentrations
of soil nutrients, trace metals and organic compounds. The results have been
summarized on Table 2.3. Table 4.18 compares the chemical components of
Blue Plains sludge with that of the average concentrations of municipal
sludges from over 150 U.S. wastewater treatment plants. The metals content
of Blue Plains sludge is comparatively low. Metals that may pose an
environmental threat due to their accumulative nature or toxicity such as
cadmium (Cd), chromium (Cr), and lead (Pb) fall well below the average
concentrations reported in other municipal sludges. The Blue Plains treat-
ment plant does not receive large volumes of industrial wastewater and there-
fore, the sludge or sludge products have these low levels of metals and other
industrial chemicals.
The evaluation and continued monitoring of metals content in sludge
will affect the success of the land application program. The heavy metals of
greatest environmental concern are mercury (Hg), cadmium (Cd), chromium (Cr)
and lead (Pb) due to their accumulative nature and toxicity to plants, animals
4-57
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TABLE 4.18
AVERAGE MAJOR CHEMICAL COMPONENTS OF SLUDGE
A COMPARISON WITH BLUE PLAINS SLUDGE
Component
Blue Plains Sludge(!)
Raw Digested
U.S. Sludge(2)
Anaerobic
Nitrogen, Total N
Ammonium Nitrogen NH4-N
Phosphorus, Total P
Potassium
Calcium (3)
Magnesium
Iron (4)
Cadmium
Chromium
Copper
Lead
Nickel
Zinc
Mercury
%
%
%
%
%
%
%
ppm
ppm
ppm
ppm
ppm
ppm
ppm
3.17
0.056
1.42
0.079
10.478
0.217
8.049
6.5
121.98
267.3
191.7
40.64
408.6
N/A (5)
3.97
0.048
1.36
0.085
11.15
0.231
7.92
5.64
109.50
279.30
171.5
38.1
428.4
N/A (5)
5.0
0.94
3.3
0.52
5.8
0.58
1.6
106.0
2,070.0
1,420.0
1 , 640 . 0
400.0
3,380.0
1,100.0
(1) Refer Table 2.4. Monthly sludge analyses from D.C. - January-May 1986.
(2) Analysis of 150 municipal sewage treatment plants in northcentral and
eastern U.S.
(3) Lime (calcium carbonate) is added for pH adjustment in the nitrification
reactors during wastewater treatment.
(4) Ferric (iron) chloride is added in the wastewater treatment systems for
phosphorus removal.
(5) Below detectable levels.
Source: Evaluation of Sludge Management Systems (EPA - 430/9-80-001).
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and humans. Section 4.4, Land Application, examines the movement of metals
into the soil from dewatered sludge. It is assumed that the transfer of
nutrients and metals into soils from dried sludge pellets is comparable to
that of dewatered sludge.
The nutrient value of dried sludge pellets impacts its effectiveness
as a soil conditioner and will impact the loading of nutrients into soils.
Life expectancies of land application sites can be determined if the nutrient
and metals content of sludge are known. Section 4.4 presents specific
methodology for calculating nutrient loading rates.
Concern over the potential transfer of pathogenic organisms into
soils is minimized by the heat drying process. There is little possibility
for disease-causing organisms to survive the temperatures inside the dryer and
the dried sludge pellet should be pathogen-free and stable. However, if the
pellet is accidentally rewetted prior to land application, the possibility for
anaerobic decomposition and organism regrowth exists. Care must be taken to
avoid rewetting of the dried pellets during the transfer, storage and all
steps prior to land application.
4.6.2 Man-Made Environmental Impacts
The Blue Plains site is situated in an area of diverse land use
most of which does not appear compatible with treatment plant operations.
However, the least compatible use, the residential complexes, are located to
the east of Blue Plains and Interstate 295 serves as a buffer between the
two. The installation of sludge drying units at Blue Plains would require a
building with an estimated area of about 68,000 square feet. The visual
impact of silos on the surrounding area may be objectionable. However, silos
in an agricultural setting, as in the case where pellets are land applied to
farmlands, have little visual impact.
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Drying sludge into pellets should reduce dusting problems. How-
ever, in the event that heavy dusting occurs during the transport and storage
of the sludge pellets, the potential for spontaneous fires exists. If dust
particles are in close proximity with high temperatures, high gas velocities
and oxygen, a fire hazard may exist.
The transport of dried sludge from the Blue Plains site would be by
truck. The number of trucks and frequency of trips will impact traffic flow
patterns on 1-295, 1-95 and across the Woodrow Wilson Memorial drawbridge.
Traffic problems have been identified at the signal light at the intersection
north of the site which is the access point for 1-295. Since heat drying
substantially reduces the mass and volume of sludge, the number of trucks
required to transport the dried sludge pellets to land application sites will
also be substantially reduced when compared to transporting dewatered sludge.
A reduction of vehicles on the surrounding interstates, in addition to
improved traffic flow conditions, may contribute favorably to the ambient air
quality in the region around Blue Plains. Any noise to the. area due to truck
traffic from the site will also be reduced.
The drying process would result in direct discharge of exhaust
gases into the atmosphere in the formation of a plume. Plumes consist of
steam heat and any pollutants that are not removed during the sludge drying
process. If not controlled, visible plumes may contribute to degradation of
the air quality in the Blue Plains region. The presence of a plume from
stacks will also have an adverse visual impact. The District's regulations
regarding visible emissions from stationary sources is restrictive and
controls to remove the plume will be necessary.
Odors may also be apparent from the exhaust gases or may result
from improper management of the sludge pellets. Accidental rewetting of the
pellets or inadequate removal of moisture during the heat drying process will
create an odor problem. Removal of a visible plume and deodorization of the
moist exhaust gases will be possible by installing an afterburner. Careful
operational practices can reduce odor problems that may result from acci-
dental rewetting of the dried sludge.
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Economic considerations associated with heat drying include the
need to find markets for the product and competition for permitted land ap-
plication sites. The transport, storage and application of sludge pellets
would require a dependency on a group of contractors. These conditions could
impact overall management control.
There are several limitations to heat drying and product use that
would affect the feasibility of using this alternative at the Blue Plains
facility. These include:
o The District's prior unsuccessful experience with heat drying;
o Undetermined market for the dried sludge pellets in the
region;
o Unproven experience with heat drying the quantities of sludge
generated at the Blue Plains facility; and,
o Uncertainty of the costs and methods of disposal of the dried
sludge (incineration or landfilling) if a land application
site is not available.
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4.7 LANDFILLING
The District has evaluated various landfill sites within the regional
area but none have been proven to be acceptable. (1) The 1-95 Lorton
Landfill, which is owned by the District and operated by Fairfax County,
appears to be the only regional site acceptable for landfilling at this time.
Maryland regulates sludge landfilling through Maryland Refuse Disposal
Regulations, Title 10, and new sewage sludge management regulations.
Virginia duplicates this with its Solid and Hazardous Waste Management Law,
Title 32.1, and solid waste regulations. In addition, the concerns of the
Virginia State Health Department, regarding the potential hazard to human
health and the environment have caused the prohibition of dewatered sludge
landfilling at the Lorton facility which is located in the Occoquan River
watershed. This is a major concern in the implementability of a landfilling
alternative for Blue Plains sludge. This section will analyze the potential
environmental impacts of codisposal of solid waste and 200 dry tons of sludge
with 50 dry tons of post lime per day at the Lorton facility.
4.7.1 Natural Environmental Impacts
Under this alternative stabilized sludge with 20 percent solids
would be applied on top of the working face of the Lorton landfill. The
sludge and refuse would then be thoroughly mixed before they are spread,
compacted and covered with soil. Sludge typically represents at least ten
percent of this mixture to assure adequate absorption of liquids by the
refuse. Application rates range from 500 to 4,200 cubic yards of sludge per
acre.
A major concern of sludge landfills is the control of ground and
surface water contamination by leachate and runoff. Monitoring of surface
water total solids, dissolved oxygen, BOD, chloride, hardness and fecal
coliform levels at Lorton, both up and down gradient, indicates that the
landfill is not currently detrimentally affecting surface water. The site is
located so that 1) no upland drainage flows into the site, 2) springs and
streams originating on-site, or adjacent to the site, are protected by
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culverts, and 3) runoff is collected in on-site basins. However, the
addition of dewatered sludge to the landfill could potentially lead to
surface water pollution and degradation of groundwater quality with improper
management or operation.
Typical quality of sludge-only landfills is shown in Table 4.19.
The actual quality and quantity of the leachate which would be produced at a
Lorton co-disposal facility is dependent on the sludge composition, soil
conditions, drainage characteristics, climate, along with chemical and
biological activity within the landfill. For this reason the composition of
the leachate cannot be defined at this point. In any co-disposal program,
the leachate components of particular concern are nitrogen, heavy metals and
pathogens. The content of Blue Plains sludge with respect to these elements
is given in several previous tables (see Tables 2.2 and 4.12).
Under anaerobic landfill conditions the predominant nitrogen
compounds are ammonia (NH3> and ammonium (NH^+). Typical low pH conditions
in landfills tend to promote a predominance of ammonium which binds with
negatively charged soil particles and becomes relatively immobile. The
amount of the more mobile nitrate form (N03> is dependent on site specific
conditions. Heavy metals are more mobile under acid conditions and are
likely to leach toward the groundwater. However, the total amount of metals
in the leachate is reduced through adsorption onto soil particles. This
condition indicates that the addition of sludge may increase the levels of
these metals reaching the groundwater unless additional leachate controls are
installed such as underground collection systems or increased drainage
modifications.
Maryland and Virginia both have regulations stating that sludge
must be treated by processes which significantly reduce pathogens (PSRP) as a
minimum requirement prior to landfilling. These processes reduce the threat
of pathogen transfer into the ecosystem, but to an extent less than that of
the incineration or composting alternatives. There is, therefore, pathogen
survival into the landfill environment. Many of the pathogens found in the
sludge (see Table 4.15) are filtered by the physical properties of the soil
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TABLE 4.19
LEACH ATE QUALITY FROM SLUDGE-ONLY LANDFILL
Constituents Values (1)
Constituents
pH 6.7
TOO 1,000
COD 5,100
Ammonia nitrogen 198
Nitrate nitrogen 0.28
Chloride 6.7
Sulfate 10
Cadmium 0.017
Chromium 1.1
Copper 1.3
Iron 170
Mercury 0.0004
Nickel 0.31
Lead 0.60
Zinc 5.0
(1) Values expressed as mg/1 except for pH.
Source: Process Design Manual: Sludge Treatment and Disposal, EPA
625/1-79-011.
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as they move downward. Daily covering of the landfill will also help to
reduce the potential impacts of pathogens carried by aerosols or airborne
solid particulates.
Landfills can potentially impact plant and animal life through the
deleterious effects of metals, pathogens, toxic organics and through the
destruction of habitat. The removal of habitat is an unavoidable impact
which can only be mitigated through the use of the maximum environmentally
safe loading rate. This action will minimize the overall acreage requirement
of the site but it may increase the threat of toxicity from overloading of
metals or pathogens, especially for those elements with relatively low toxic
levels, such as cadmium or mercury.
The extent of the impact on the natural environment can be cor-
related to the quality of the sludge and solid waste in the landfill. Metals
are at comparatively low levels in Blue Plains sludge (see Table 4.18).
Current monitoring practices would continue to measure the solids content,
volatile solids, nitrogen, inorganic ions, bacteriological quality, toxic
organic compounds and pH of the sludge and the extractable portions of the
sludge/refuse mixture. This program would help identify potential contamina-
tion problems and adequate mitigative measures before the environmental
impacts become severe.
Another impact of landfilling is the production of gases and
odors. Decomposition of organic matter in a landfill produces methane and
smaller amounts of hydrogen sulfide. These gases may reach explosive concen-
trations around site buildings and gas collection and venting systems are
necessary for safe operations. Hydrogen sulfide, along with other gases, can
also produce malodors in the vicinity of the landfill. The Lorton facility
currently experiences this problem and sludge addition has the potential of
further contributing to this problem. Daily cover and thorough mixing of
materials will help in minimizing the amount of these odors produced through
absorption of liquids and filtering of the waste through soil.
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4.7.2 Man-Made Environmental Impacts
One of the major areas of concern with respect to the development
of the landfilling alternative is the unavailability of a suitable site. The
District has evaluated potential landfill sites in the past and determined
that the Lorton facility is the only suitable site for sludge landfilling.
However, Virginia has prohibited the landfilling of dewatered sludge at
Lorton because of its location in the Occoquan River watershed. This restric-
tion would have to be overcome prior to serious planning consideration of the
alternative. In addition, Maryland prohibits the landfilling of sludges with
free liquids. This increases the costs involved in dewatering the sludge
prior to landfilling.
This alternative also has the potential of affecting the community
and cultural resources of the area by impacting upon local schools and
recreational facilities. Two elementary schools are located in the vicinity
of the Lorton site. One school is located 5,000 feet northeast of the site
on Legion Drive near Lorton Road, the other, Gunston School, is 8,000 feet
east of the site on Route 611, near the intersection of Gunston Hall Road.
These facilities may be impacted by odors and transportation vehicles if a
route passes by the school. Trucks may introduce noise, air pollutants,
traffic congestion and the potential for spills into the environment. Local
recreation facilities include an area south of the landfill along the
Occoquan River and extending northward along 1-95 and the Pohick Bay Regional
Park, located east of the site on Mason Neck. These areas may be impacted in
ways similar to the educational facilities. Proper operating and emergency
programs will aid in minimizing the potential for substantial environmental
impact.
At least 37 to 44 truck trips per day would be required for dis-
posal of sludge generated at the Blue Plains WWTP. The hauling route from
the Blue Plains WWTP to Lorton landfill is via Interstate 1-95 to within
three miles of the disposal site. Furnace Road serves as the access road to
the Lorton landfill from 1-95. Interstate 1-95 was designed to handle heavy
trucks and could easily accommodate the impact of increased traffic. Traffic
volumes on 1-95 in the vicinity of the Lorton site range from 67,490
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vehicles/day (between Route 124 to Route 1) to 87,200 vehicles/day (from
Backlick Road to Old Keene Mill Road). Average traffic volume between Route
1 and the District of Columbia is 99,870 vehicles/day; 6,300 vehicles/day are
trailer trucks and 760 are 3-axle, 6-to-10 tire trucks. The highest volume
of traffic on this thoroughfare is encountered from Route 644, Springfield,
to Route 395-495 (139,500 vehicles/day). Furnace Road is paved and is in
good condition. Traffic volume on Furnace Road from Route 123 to Hoes Road
averages 1307 vehicles/day and increases to 1414 vehicles/day at Lorton
Road. The highest traffic volumes on Furnace Road are encountered between
the north intersection of Lorton Road to the south intersection of Lorton
Road (4,421 vehicles/day). Within the Lorton site, all roads are paved and
approach within 0.25 miles of the operating face of the landfill. (All
traffic counts are 1984 values).
Another area of impact on the man-made environment is the potential
degradation of the local aesthetics. However, the site is surrounded by
trees which provide an effective visual buffer for all local roadways except
the weigh station area off Furnace Road. This minimizes the overall
aesthetic impact of the landfill and the addition of sludge will not greatly
alter existing conditions. The most effective methods of mitigating the
aesthetic impacts include daily covering of the landfill and maintenance of
the vegetative buffer zone.
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4.8 OCEAN DISPOSAL
Currently, about four percent of municipal wastewater sludge produced in
the U.S. is ocean disposed. The dispersion of sludge in the water column is
described in Section 2.8 and illustrated in Figure 2.12. Basically, volatile
organics evaporate into the atmosphere; grease, oil and scum remain on the
surface; and the remaining sludge fraction sinks in an expanding cloud toward
the ocean floor. The dispersion rate is site specific and is dependent on
the temperature, salinity, depth, currents and composition of the sludge.
EPA issuance of an ocean disposal site permit to the District would require a
demonstration that no practicable alternative is available that has less
impact on the environment.
4.8.1 Natural Environmental Impacts
The impact of sewage sludge on the marine environment is dependent
upon the interactions of sludge and seawater. Ocean disposal of sludge has
the potential for adverse impacts on ocean sediments, the water column and
marine biota. Ecosystem impacts may be minimized either by containing the
pollutants in a very small area (to concentrate the toxic substances) or by
dispersion. Impacts on biota, especially benthos, can best be mitigatsd by
dispersing the contaminants in the water column, thereby diluting them before
they reach bottom.
The release of nutrients at deepwater sites tends to stimulate
the ecosystem by adding limiting nutrients, such as nitrogen, necessary for
biomass production. Increased production of phytoplankton and other plant
life result in changes in local water quality and species composition. How-
ever, studies of phytoplankton nutrients and productivity indicate that the
effects of sludge dumping on planktonic composition in the New York Bight are
localized and almost imperceptible. (37) The annual production of the Inner
Bight, which is comparable to that of very productive upwelling systems, is
caused by the influx of nutrient rich water from the estuaries which flow
into the Bight. (37) Therefore, the overall impact of nutrient loading is
highly site specific and dependent on background conditions surrounding the
disposal site.
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A significant portion of the heavy metals in sewage sludge is con-
tained in the particulate fraction. Field analyses at the Hyperion Sewage
Treatment Plant in Los Angeles, California, show that many of these metals
become soluble in seawater (See Table 4.20). As soon as the sludge is
dumped, there is a rapid, initial first-stage release of metals, followed by
a slower, second-stage release. The first-stage release is attributable to
the oxidation of organic particles and metal sulfides and to the desorption
of metals from particles. Metals not dissolved or oxidized during first-
stage release may be released in time as the organic matter with which they
are bound decomposes or as they are desorbed from inorganic material. The
amount of metals typically released into the water column is shown in
Table 4.19.
TABLE 4.20
RELEASE IN SEAWATER OF
HEAVY METALS FROM SLUDGE(!)
Metal
Percent Released
Est. Annual Tons
of Metals Released
From Blue Plains (2)
Cadmium
Chromium
Copper
Lead
Manganese
Nickel
Zinc
93-96
2
5-9
35
35
49-64
18-39
3.2-3.3 tons/yearO)
1.3
8.5-15.4
36.8
11.4-14.9
47.2-102.4
(1) Source: Rohatgi and Chen, 1975.
(2) Gannett Fleming Environmental Engineers, 1987.
(3) Values based on discharge of 346 dry tons/day.
The extent of metal and organic chemical concentration increases
observed at a given disposal site is dependent on the sludge quality. The
constituent concentrations of the Blue Plains sludge are contained in Table
4.12. The accumulation of toxic metals and organic compounds in the food
chain poses the potential human health effects of ingesting contaminated
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seafood. The biomagnification of metals in Che food chain has not been
reported, except for methyl mercury, USEPA regulations currently prohibit
disposal of sludge containing mercury and mercury compounds that would raise
background concentrations by 50 percent after dispersion. Organic contami-
nants, such as halogenated hydrocarbons, tend to bioaccumulate up the food
chain and have persistent long-term effects. Other compounds, like poly-
cyclic aromatic hydrocarbons, do not tend to biomagnify and degrade more
readily.
Organic constituents of ocean dumped sludge are subject to oxida-
tion and scavenging in both the water column and bottom sediments. Duedall
et al. demonstrated that the organic carbon content of bottom sediments in
the vicinity of existing sewage sludge dump sites is not high when compared
with that in other coastal areas. Further, they postulated that different
microorganisms act to hydrolyze the organic matter in sludge, and this leads
to a reduction in the dissolved oxygen levels in seawater.
Several studies have shown that materials within the surface slick
may be released into the atmosphere on jet drops from bursting bubbles.
Typically higher concentrations of bacteria near the surface should then be
reflected in the bacterial content of the jet drops. This has been found to
be the case in laboratory studies but has not been tested under field condi-
tions. (41) This process presumably has the same impact on particulate
trace metals. Lead, iron, manganese, chromium and vanadium have been found
in significantly higher concentrations in the surface layer. In addition,
enrichments of organic carbon on the seasalt aerosol have been measured in
levels which indicate the same sea to air transfer process. (42) The
significance of this process is related to the known impacts of aerosols from
sewage treatment plants, cooling towers and tanneries: These emissions
contain bacterial aerosols that travel to outlying areas and have produced
viral disease. (Wellock, 1960). Therefore the potential exists of diseases
being caused by these agents in oceanic and coastal environments.
Most oxygen in the ocean enters from the atmosphere through the
air-water interface. The rate of this exchange is fairly slow and depends on
surface mixing rates and boundary layer diffusion. The concentration of
4-70
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oxygen at saturation is a function of both salinity and temperature of the
water and, therefore, varies on a seasonal basis. Waste disposal may cause
an initial transient decrease in oxygen due to microbial actions and inor-
ganic oxidation of reduced compounds. (Odum, 1960). Oxygenated seawater
will oxidize such materials as ferrous and manganous ions, causing them to
precipitate. There will then be a longer term oxygen demand as disposal
materials slowly degrade. The relatively low levels of these materials in
Blue Plains sludge (see Table 4.17) will reduce the potential impact of an
increased oxygen demand although overloading and periodic site conditions
which concentrate the contaminants may result in lessened water quality.
The presence of hydrogen sulfide, a product of anaerobic reduction
of sulfur compounds, indicates conditions which may affect biological com-
munities. Hydrogen sulfide is toxic in low concentrations to many aerobic
organisms. When this compound is released into oxygenated water, it is
oxidized within hours and may account for a major fraction of the initial
chemical oxygen demand of certain wastes. Because of its short half-life in
aerated water columns, hydrogen sulfide does not normally represent a long-
term hazard.
Studies at the Philadelphia sewage disposal site, located approxi-
mately 35 miles east of Ocean City, Maryland, found evidence of pollution of
the benthic environment in the vicinity of the disposal site within 5 years
after sludge disposal commenced in 1973. Positive indications of bacterial
and viral contamination were in evidence up to 3 years after sludge dumping
ended. Pollution included accumulations of metals in organisms and sedi-
ments, sludge deposits on the ocean bottom, bacteria normally associated with
sewage, a change in the structure of the benthic community, and pathological
conditions in bottom dwelling crustaceans. (40) Studies conducted in the
New York Bight showed bacteria in disposal sites 3-5 years after dumping
ceased.
Bacterial contamination may occur as a result of the ocean disposal
of sludge. Shellfish near the New York Bight sludge dumpsites contain high
concentrations of coliform bacteria. (37) Coliform counts exceeding FDA's
standards have been found in surf clams collected five miles from the center
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of the site. Pathogens released through sludge disposal may present a human
health risk by consumption of contaminated shellfish. Sludge stabilization
prior to ocean disposal reduces the risk of bacterial contamination.
Benthic organisms are usually in contact with polluted sediments
and overlying water for long periods of time, and therefore are good indica-
tors of chronic pollution. Benthic organisms form an important link in the
marine food chain as they are important food sources for many sport and food
fishes. They also accumulate contaminants such as trace metals, petro-
chemicals and organic pollutants. (34) The small fraction of dumped sludge
which reaches the sea floor is further affected by biological activities and
physical forces. Benthic organisms burrowing in the deposits incorporate the
material into existing substrates, reducing the possibility that it will be
transported out of the area. Benthic organisms consume fine sludge solids
and excrete them, along with other waste products, as coarse pellets, thus
reducing the potential for resuspension.
Contamination of benthic organisms and plankton can impact the
human environment through biomagnification of pollutants and entrance into
the food chain. For this reason, EPA established limiting permissible concen-
trations (LPC) based on a toxicity threshold of .01 of the concentration
proven to be acutely toxic to sensitive marine organisms in bioassays. The
result of the bioassay is the concentration of sludge in ocean water that is
acutely toxic to half of the marine organisms within a 96 hour period.
4.8.2 Man-Made Environmental Impacts
The Potomac River is approximately 3,000 feet wide at the Blue
Plains site. There are many activities associated with loading and transport
of sludge on the Potomac River that may impact the river. The increase in
barge activity could impact recreational activities such as boating and
fishing. The risk of inland waterway pollution and the potential for health
problems are also increased if an accidental spill should occur during the
loading and transport of sludge.
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The land requirements at Blue Plains for ocean disposal would
include area for sludge storage, barge docking and loading facilities. Spare
barges and/or excess tank capacity are needed for sludge storage during
periods when the vessels are in transit and during times when disposal opera-
tions are disrupted. Numerous factors which may impact storage requirements
include inclement weather, equipment breakdown, labor disputes and the
distance the barge must travel to and from the disposal site. Sludge manage-
ment problems will be magnified if sludge must be stored for lengthy periods
of time due to disrupted barge transport.
The risk of pollution to the Potomac River is increased if sludge
is accidentally spilled during loading operations. The presence of floating
sludge, grease, oil and scum on the surface of the water will create an
aesthetically undesirable appearance. The fraction of the spilled sludge
that sinks to the river bottom will impact the ecosystem through the addition
of nutrients, pathogens, metals and organics. Measures to minimize the
adverse affects from an accidental spill should include the development of a
spill prevention plan and the proper training of personnel to handle contain-
ment techniques and cleanup.
Ocean pollution due to accidents at sea will impact disposal sites
and, if weather conditions are severe and high winds exist, the sludge may be
widely dispersed. Containment and cleanup at sea is difficult and would
require a temporary storage barge and an additional tugboat. In some cases
severe weather may hinder efforts to protect the environment due to accidental
spills.
Weather conditions are a major consideration when looking at the
ocean disposal alternative. Delays in barge trips due 'to inclement weather
will impact storage capacity and can prevent disposal of the sludge at the
designated site. If weather is too severe, the vessel may be required to
return and make a second trip. The scheduling of longer trips necessitates
the use of long-range forecasting which is generally unreliable. Measures to
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avoid impacts associated with bad weather are proper on-site storage facili-
ties for the sludge and the availability of extra barge equipment. The use
of larger barges, which will withstand harsher weather conditions, could
reduce the risk of delays.
Increased barge traffic along the Potomac River will increase the
potential for erosion of the river bank due to the wakes created by a moving
barge. Daingerfield Island Park, on the west shore of the Potomac River in
Alexandria, is a major recreational facility and barges at Blue Plains will be
completely visible to anyone in the park area. Small craft operators risk
serious injury if the craft accidentally gets into the path of an on-coming
barge.
Barges departing from Blue Plains would pass under the Woodrow
Wilson Memorial drawbridge. If bridge openings are required for the barge
operations, which usually includes a tugboat, traffic patterns on 1-95 across
the bridge will be disrupted.
A significant environmental impact of the disposal of sludge in the
ocean will result if sludge materials wash to the shoreline from the off-
shore disposal sites. Not only will the presence of sludge or sludge by-
products degrade the beaches, public reaction to sludge washing up on the
beaches will be negative.
On June 23, 1988 the Senate Environment and Public Works Committee
approved a bill that would ban ocean dumping of municipal sewage sludge by
1992. The Bill (S.2030) establishes a deadline of December 31, 1991 on ocean
disposal and would require municipalities dumping at the 106-mile site to
enter into consent agreements with EPA to submit detailed alternative
disposal plans. Failure to meet consent agreement deadlines could result in
fines of $20 to $40 per ton of sludge dumped with a maximum penalty of
$50,000 per day under the bill.
The House Merchant Marine and Fisheries Committee approved a
similar measure (H.R. 4338) on June 9, 1988. The House bill extends the
ocean dumping deadline to December 31, 1992 and has higher penalties.
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The House Public Works and Transportation Committee is expected to
consider ocean dumping legislation under a 60-day limitation that could
result in House consideration by the end of 1988.
4-75
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4.9 ADVERSE IMPACTS OF THE ALTERNATIVES AND MITIGATIVE MEASURES
This chapter describes the potential environmental impacts of the seven
sludge management alternatives under consideration. This Section reviews the
most significant impacts and identifies the measures that can be used to
mitigate those impacts. Table 4.21 provides a summary of the impacts with a
corresponding list of measures to minimize their effects on the natural and
man-made environment. Some of the impacts listed in the Table cannot be
mitigated and must be accepted as consequences of a given alternative. Other
impacts can be partially or completely mitigated through pretreatment, trans-
portation management and off-site controls.
4.9.1 Sludge Management
Consistent and adequate (based on regulations) pretreatment of
sludge is a key factor in minimizing the impacts of any of the sludge manage-
ment alternatives. Maintaining consistent sludge characteristics makes
product processing easier and allows for regular loading rates in land
application and drying/product use programs. Pretreatment which includes
Processes to Significantly Reduce Pathogens (PSRP) will reduce the threat of
pathogen transfer under each of the alternatives. Part of maintaining a
consistent product is the utilization of proper sludge processing controls.
This includes consistent pretreatment as well as a constant moisture content,
maintaining combustion efficiency under incineration, adequate mixing and
aeration of compost and proper operation of pollution control devices
described in the incineration and drying sections.
Providing adequate cover for the sludge or sludge products will
help reduce product moisture levels, potential leachate and runoff production
and the presence of malodors. This is particularly appropriate under the no
action, composting and drying/product use alternatives.
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TABLE 4.21
SUMMARY OF POTENTIAL IMPACTS
AND MITIGATIVE MEASURES
ALTERNATIVE
NO ACTION
IMPACTS
Stockpiling materials at Blue Plains
o Pile leachate
o Surface and groundwater contamination
o Rodents
Production of maIodors
Nutrient and metal overloading of soil
Heavy transportation requirements
o Costs
o Disruption of traffic patterns
o Lack of management control
MITIGATIVE MEASURES
o Leachate collection and treatment
system
o Off-site storage
o Expansion of sludge product market
o Divert wastewater to other treat-
ment facilities
o Limit new construction in area
served by collection system
o Restrict stockpiling
o Complete aeration and mixing of
compost
o Prompt incorporation using modern
methods
o Calculation of loading rates with
current sludge properties
o Long-term competitive contracts
o Schedule truck trips for off-peak
hours
o Unavoidable
INCINERATION
Air emissions
Scrubber water
Stack height
o Visual
o Air traffic safety
Ash landfill ing
o Ash transport
o Ash disposal
o Proper maintenance and operation
of furnace to ensure combustion
efficiency
o Install proper pollution control
system
o Restrict sludge feed rates
o Recycle to head of plant
o Unavoidable
o Proper markings on stacks
o Coordination with F.A.A.
o Proper management
o Leachate collection and treatment
systems at landfill
o Groundwater monitoring
o EP toxicity testing
LAND APPLICATION
Nutrient and metal overloading of soil
Production of maIodors
Pathogen transfer
Ground and Surface water contamination
Off-site storage requirements
o Costs
o Disruption of traffic patterns
o Lack of management control
Land use conflicts
Seasonal limitations
o Calculation of loading rates with
current sludge properties
o Adhere to Virginia, Maryland
regulations
o Prompt incorporation
o Pretreatment with Process to
Significantly Reduce Pathogens
o Proper loading rates
o On-site run-off controls
o Groundwater monitoring
o Long-term competitive contracts
o Schedule truck trips for off-peak
hours
o Avoidable through proper contractor
selection and management
o Site availability
o Proper siting and buffering of
application sites
o Unavoidable, but overcome through
storage practices
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TABLE 4.21 (Cont'd.)
SUMMARY OF POTENTIAL IMPACTS
AND MITIGATIVE MEASURES
ALTERNATIVE
COMPOSTING/PRODUCT USE
IMPACTS
Heavy metal concentrations in soil
and crops
Fire
Production of meIodors
Leachate, condensate and runoff to
surface waters
Heavy transportation requirements
Use of remaining plant area at Blue
Plains
Product market
Seasonal limitations
MITIGATIVE MEASURES
o Chelated in compost process
o Restricted loading on crops for
human consumption
o Proper operating procedures
(aeration, mixing)
o Treatment of gaseous discharges
o Proper mixing with bulking agent
o Liquids collection system
o Recycle liquid runoff to head of
treatment plant
o Long-term competetive contracts
o Schedule truck trips for off-peak
hours
o Design that includes efficient use
of space
o Quality assurance of product
o Aggressive regional marketing program
with contract sales agreement
o Unavoidable, but amenable to manage-
ment
DRYING/PRODUCT USE
Particulate emissions/gas plume
o Fire hazard from dust
accumulation
Resetting dried sludge pellets
o MaIodors
o Leachate
o Bacterial decomposition
Nutrient and metal overloading of soil
Pathogen transfer
Liquid sidestream
Land application seasonal
o Installation of proper pollution
control systems
o Pelletization
o Proper storage facilities
o Proper handling
o Proper endpoint use
o Calculation of loading rate with
current product properties
o Pretreetment with Processes to
Significantly Reduce Pathogens
o Recycle to head of treatment plant
o Unavoidable, but amenable to manage-
ment
LANDFILLING
Ground and surface water contamination
Pathogen transfer
Gas and odor production
Landfill ing Occoquan watershed
prohibited for dewatered sludge
o Leachate collection and treatment
system
o Proper mixing
o Daily soil cover
o Pretreatment
o Proper mixing
o Daily soil cover
o Landfill gas collection and venting
systems
o Location of new landfill
o Siting landfill outside watershed
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TABLE 4.21 (Cont'd.)
SUMMARY OF POTENTIAL IMPACTS
AND MITIGATIVE MEASURES
ALTERNATIVE
OCEAN DISPOSAL
IMPACTS
Water pollution (metals, toxic
organics, DO reduction)
Biomagnification of pollutants
Sludge spill
Barge traffic
o Riverbank erosion
o Disrupted recreational boating
and fishing
Disruption of vehicular traffic at
drawbridge
weather conditions
o On-site storage facilities
o Barge storage
MITIGATIVE MEASURES
o Pretreatment to remove pollutants
o Concentration or dilution in
larger area
o Spill prevention practices
o Operator training
o Equipment maintenance
o Structural controls on riverbanks
o Use of smaller barges at slower
o Unavoidable, but timing departures/
arrivals could reduce impacts
o Construct sludge storage facil-
ities
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4.9.2 Sludge Transport
Transport of sludge/sludge products has the potential of environ-
mental impact through spillage or riverbank erosion and/or impacts related to
traffic disruption and additions to the present traffic volume. Spill pre-
vention procedures include vehicular maintenance and personnel training.
Emergency procedures should be outlined and adequate equipment made available
in the event of an accidental spill. Large barges necessary for the ocean
disposal alternative will contribute to riverbank erosion. The use of smal-
ler barges at slower speeds may reduce this problem but will require the use
of more barges. This will in turn increase the amount of traffic disruption
by increasing the number of times the Woodrow Wilson bridge must be raised.
The composting, no action, land application, drying/product use and landfil-
ling alternatives have high truck transportation requirements. These
requirements are unavoidable impacts if all of the sludge products are to be
utilized or disposed in either a single or mixed alternative(s) scenarios.
4.9.3 Sludge Disposal
Surface application of sludge or sludge products has the potential
of overloading soil and crops with nutrients and heavy metals. One method of
mitigating this impact is through proper calculation of loading rates based
upon current sludge characteristics, site specific properties, and maximiza-
ing of the amount of land available for land application. Sample calcula-
tion of loading rates based upon sludge nutrient and metal content and soil
properties can be found in Section 4.4, Land Application. Actual calcula-
tions must follow state regulations in order to mitigate the potential
impacts of nutrient and metal overloading. The amount of land available for
application of sludge, dried sludge pellets or compost can be increased by
maintaining the quality of the sludge and aggressive marketing of sludge
products. Current problems with marketing Blue Plains compost may be
alleviated through the increased process control achieved through in-
vessel composting and contract sale program. However, an effective marketing
campaign is the key in developing an adequate area for either compost or
sludge application programs.
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In-vessel composting an average of 200 DTPD would require an
estimated 16 acres of land. This land requirement may conflict with the
installation of the swing sedimentation basins at Blue Plains and other land
uses for solids management.
The landfilling alternative involves the use of the Lorton landfill
for co-disposal of dewatered sludge. This has been prohibited in the
Occoquan watershed by the Virginia State Department of Health. This may be
an unavoidable impact unless another existing landfill or new site outside of
the Occoquan watershed can be located.
The no action, incineration, land application, composting, drying
and landfilling alternatives will all require the use of leachate collection
and treatment systems and surface water controls. Control of leachate at
landfill sites includes the use of underdrains and liners. Specific areas
must be separated for collection and treatment of leachate. Runoff from the
landfill site or sludge processing areas should be collected and treated
prior to discharge into surface waters.
Grading to minimize slopes and slope length as well as protective
structures such as swales or culverts to nearby streams will mitigate runoff
into surface waters from land application sites. If these measures are
implemented at the sites erosion and off-site transfer of sludge or the
enriched soil will be minimized.
Prior to land applying dewatered sludge or dried sludge products,
off-site storage areas must be set up and maintained. Measures to avoid
leachate formation, runoff or spillage of sludge are necessary to protect the
environment at the site and the surrounding areas. Adequate storage cap-
acity, regular inspection of temporary lagoons and operator training are
requirements for spill prevention and facility maintenance. Therefore, off-
site storage can help alleviate on-site storage problems but can result in
other environmental impacts if not managed properly.
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Landfilling dewatered sludge has the potential for pathogen trans-
fer and gas and odor production. Pretreatment of sludge contributes to the
mitigation of these impacts. Additional controls include proper mixing with
the solid waste at the working face of the landfill to assure absorption of
excess liquids and daily soil covering to minimize the amount of airborne
particulates and aerosols. These actions will help improve the aesthetics as
well as mitigate the other impacts listed here.
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CHAPTER FIVE
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CHAPTER 5
SCREENING OF SLUDGE MANAGEMENT METHODS
5.1 INTRODUCTION
In the preceding chapters of this document, six sludge management
methods have been examined. With the exception of the no-action option,
which combined land application and composting, each uses a single technology
(excluding FONSI'd and MCCF sludge).
In this chapter these methods are screened to eliminate those which are
the least desirable.
5.2 BASIS FOR SCREENING
Table 5.1 provides a summary of the evaluation factors and character-
istics of the six sludge management methods which have been described in
detail in Chapters 2, 3, and 4. In addition to the evaluation factors iden-
tified on Table 5.1 (i.e. costs, operability, implementability and environ-
mental factors) comparison of the sludge management methods must include
consideration of Section 101(b)(6) of Title I of the National Environmental
Policy Act of 1969 (NEPA).
5-1
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Table 5-1
Comparison of Alternatives
Alternatives
Evaluation Factors
Total Equivalent
Annual Costs
Incineration With In-Vessel Drying & Ocean
Ash LandfillIng Land Application Composting Product Use landfillira Disposal
6 Unite 4 Units
$21,298,000 $19,053,000 $20,218,000 $28,735.000 $15,130,000 $24,704,000 $8,164,000
Qperabilitv Moderate
Inclementability High
Potential Environmental Adverse Impacts
Moderate Moderate Low
High Moderate Moderate
Air
o
0
Impacts
Stack Emissions X X
Odor Emissions X
X
Water Impacts
0
o
Land
o
0
o
o
o
Surface Water X1 X1 X2
Groundwater X1 X1 X2
Impacts
Transportation X
Land Use Conflicts X
Nutrients Overloading X3
Landfill Capacity X X
Aesthetics X X
X
X
Low
Low
Low
Lou
1 Potential impact at landfill; leachate generation from ash residue.
2 Impacts are possible but extremely low because of guidelines and regulatory controls.
3 Nutrient overloading* are rewote if state guidelines are followed.
26042.000
JJBAD011
5-2
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Section 101(b)(6) specifies that it is the responsibility of the Federal
Government to "enhance the quality of renewable resources and approach the
maximum attainable recycling of depletable resources". In addition, and in
concert with this responsibility, EPA established on June 12, 1984 a policy
dealing with municipal sludge management that states, "The Agency will
actively promote those municipal sludge management practices that provide for
the beneficial use of sludge while maintaining or improving environmental
quality and protecting public health." (18)
Many federal laws require environmentally sound management of municipal
sludge and several of these laws emphasize the importance for sludge
utilization and reuse. These include the Clean Water Act; Clean Air Act;
Resource Conservation and Recovery Act; Marine Protection, Research and
Sanctuaries Act; and the Toxic Substances Control Act. To implement the
policy, the EPA has established the following guidance:
o EPA believes that the risks, benefits, and costs of all sludge use
and disposal practices should be considered on an intermedia basis
when formulating and implementing sludge regulations and management
programs. Potential short-term and long-term impacts to public
health and the environment should be addressed to ensure that the
options chosen protect human health and the environment.
o EPA believes that minimization of potential widespread or
irreversible impacts, as well as involuntary hazards, should
receive primary emphasis in both regulations and sludge management
decisions. Where the risks are uncertain but potentially
significant, additional safeguards may be needed.
o EPA believes that the planning and operation of wastewater and
sludge treatment processes should be closely integrated to control
both sludge volume and sludge quality.
o EPA believes that contaminant levels in municipal sludge which
interfere with its management should, whenever possible, be con-
trolled at the source through changes in waste generating
activities or through local pretreatment requirements beyond the
minimum requirements specified by Federal categorical standards.
o EPA believes th&t beneficial sludge use should be the intent of
major sludge management technologies of the future and has devoted
research in support of them. Regulations and guidelines that
establish the requirements for these systems are essential to the
wider use of these technologies.
5-3
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EPA believes that in most cases States should have the primary
responsibility for implementing regulatory programs for sludge use
and disposal which provide for clear and expeditious decision-
making, and the States should help local governments and others to
develop, implement, and maintain proper sludge management systems.
EPA encourages public and private sector development of improved
sludge management and pretreatment technologies and practices that
increase the number of cost effective and environmentally
acceptable sludge management methods available.
5-4
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5.3 SCREENING
The screening of the sludge management methods was performed by
eliminating the.weakest methods first. The results of the screening are
summarized below in order of elimination of methods.
5.3.1 Landfilling (eliminated)
Landfilling is the weakest method. It has high cost and has low
operability and implementability rankings. It does not meet EPA's goal of
beneficial use.
5.3.2 Ocean Disposal (eliminated)
Ocean disposal is not implementable because other methods of
disposal are available to the District. Additionally, it also does not meet
EPA's goal of beneficial use.
5.3.3 Composting (eliminated)
Composting does meet EPA's beneficial use criterion. The District
is already committed to composting 210.5 DTPD (51.3%) of the sludge through
the FONSI'd project and MCCF. However, there are significant problems
associated with additional composting. There is not sufficient space on
site. Essentially all new unused space will be used for nitrogen removal
facilities mandated by the Chesapeake Bay Agreement. Therefore, to fit the
necessary in-vessel units on-site it would be necessary to place them in an
expensive multi-story structure. Additionally, there would be significant
technical obstacles associated with handling exhaust air from this large
number of in-vessel units.
5.3.4 Drying and Product Use (eliminated)
Sludge drying is an attractive method from the standpoint of cost
and reuse of the sludge. However, sludge drying on this scale in the
Washington, D.C. area may have implementation problems. Unlike composting or
5-5
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land application, there is no experience demonstrating that the dried sludge
can effectively be marketed and disposed. Although drying may be worth
considering on a trial pilot basis for a small part of the sludge, there
appear to be unreasonable risks associated with implementing it on the scale
of 200 DTPD.
5.3.5 Incineration and Ash Landfilling (retained)
Incineration has significant implementation advantages to the
District in that it enables the District to independently control sludge
management. It also can be effectively accomplished within the limited Blue
Plains site. Its chief disadvantage is that (other than some energy
generation) it does not meet EPA's goal for beneficial use.
5.3.6 Land Application (retained)
Land application is a proven method that meets EPA's goal for
beneficial use. It's principal disadvantage is that it relies on outside
contractors and jurisdictions. This makes it more uncertain and difficult
than incineration for the District to administer. Nevertheless because of
its economic and reuse advantages, it is retained for further consideration.
5-6
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CHAPTER SIX
-------
CHAPTER 6
DEVELOPMENT AND EVALUATION OF FINAL ALTERNATIVES
6.1 INTRODUCTION
Preceding chapters examined and screened sludge management methods. This
chapter describes a procedure in which final alternatives are developed from
the sludge management methods that remained after the Chapter 5 screening
process.
To develop the final alternatives, it is useful to review and further
consider the overall sludge management needs facing the District.
6.2 OVERALL SLUDGE MANAGEMENT
The District will be managing and disposing of sludge in several ways.
The long-term plans are that 87.5 DTPD will go to the Montgomery County
Composting Facility, and 123 DTPD will be composted by an in-vessel system at
Blue Plains. The remaining sludge (200 DTPD average, 384 DTPD peak month) is
the subject of this EIS.
Figure 6.1 is a representation of the quantities of sludge, and their
disposition, over the planning period. Assuming that total sludge quantities
increase rapidly by 1998, approximately 200 DTPD will be going to agricultural
land application if further action is not taken. With a more moderate growth
in sludge quantities, the total sludge handling capacity of 410.5 DTPD will
not be needed until around 2010.
The District has indicated that the rate of increase in sludge quantities
cannot be predicted accurately. The rate will depend upon population
increases in the Washington metropolitan area and process changes at the
treatment plant. This uncertainty is a factor to be considered in developing
sludge management alternatives.
6-1
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6.3 DEVELOPMENT OF ALTERNATIVES
6.3.1 Methodology
EPA recognizes that there are planning and environmental advantages
in developing and maintaining a flexible and technically varied management
program. This is reflected in the decisions to send some of the sludge
off-site (to MCCF), and to compost some on-site (FONSI'd sludge). Consistent
with that approach, this EIS endeavors to develop alternatives that will
continue to provide the desired long and short-term flexibility for the
remainder of the sludge.
6.3.2 No Action Alternative
The no-action alternative would rely upon full utilization of the
MCCF, on-site in-vessel composting as approved by the FONSI, and continued use
of land application at approximately current levels. The disposition of all
sludges under this alternative is represented in Figure 6.2.
6.3.3 Incineration (District Concept)
The District proposes to construct 6 fluid bed incinerators to
dispose of the sludge. Figures 6.3 and 6.4 show the disposition of sludge in
this alternative under both average and peak month conditions, assuming 4
incinerators are operating. The figures show that 4 incinerators are adequate
for both average and peak periods. They also indicate that for the "average
rate sludge production" scenario, all 4 incinerators will not be required
until 2010.
In previous chapters, information was provided on a "4 incinerator"
system as well as the proposed 6 incinerator system. Inasmuch as 4 incinera-
tors are adequate to handle the 200/384 DTPD, 6 incinerators are clearly not
required.
6-2
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o
Booms jo AVQ
SNOI
6-6
FIGURE 6.4
-------
6.3.4 Land Application
The land application alternative would continue indefinitely. As
shown by Figure 6.5, overall quantities of sludge going to land in the long-
term would be comparable to current quantities. The primary differences
between the no-action and land application alternatives are that under the
land application alternative, dewatering would be upgraded and the program
would expand to meet both average and peak disposal needs of the District.
6.3.5 Combined Incineration/Land Application
Combined incineration/land application provides flexibility in the
short and long-term that neither of the single-method alternatives provides.
This alternative is based on:
o Construction of two fluid bed incinerators and related
facilities (rated capacity; 133 DTPD each).
o Operation of one incinerator at a derated capacity (100 DTPD)
and the second kept as standby under average conditions. (This
is considered very conservative. Most of the time, both
incinerators could be operating).
o Operation of both incinerators during the peak month at an
assumed capacity of 100 DTPD each.
o Land application of all other sludges during both average and
peak periods.
Figures 6.6 and 6.7 depict the disposition of sludge using the
combination alternative. Figure 6.6 shows that when only one incinerator is
operating, approximately 100 DTPD on average would go to land application in
2010. Under peak conditions, 184 DTPD would be land applied.
6-7
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lOz
O.K-W
I
*
39anis
AVQ
SNOI Ada
6-8
FIGURE 6.5
-------
g
<
o
Q. Li
-------
g
<
o
_
z,x
m Cm
0> 3
o
8
-------
6.4 EVALUATION OF THE ALTERNATIVES
6.4.1 Costs
Capital, operating, and present worth costs have been estimated for
each of the three final sludge management alternatives. The costs are
summarized in Table 6.1. All cost estimates are consistent with estimates
developed in previous chapters. Additional cost details are shown in the
Appendix.
The present worth and total annual equivalent cost of all three
alternatives are similar. Considering the range of accuracy of these
estimates, they must be considered essentially equal.
The distribution of costs, however, is extremely variable. The land
application alternative has a low capital cost and high operating costs. The
alternatives that include incineration have higher capital costs and lower
operating costs than land application.
Capital costs associated with the incineration alternatives are
lower than they would normally be because it is assumed that existing struc-
tures would be used to contain the proposed incinerators. As a consequence,
the cost of the structures are considered "sunk costs" and are not included in
this evaluation.
Costs for the "No-Action" alternative will be essentially the same
as those for the land application alternative.
6.4.2 Environmental Impacts
The environmental impacts of the three alternatives were reviewed,
and are summarized in Table 6.2. The impacts of the total incineration and
land application alternatives were detailed in Chapter 4.
6-11
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Cost Component
TABLE 6.1
SUMMARY OF SOLIDS MANAGEMENT ALTERNATIVES
PRESENT WORTH COST ANALYSIS (1)
LAND
APPLICATION
TWO UNIT
INCINERATION/
LAND APP.
FOUR UNIT
INCINERATION
10/12/88
BPTC
DISK*1
CAPITAL COSTS
1988 Estimated
Project Cost
OPERATION AND
MAINTENANCE COSTS
Annual O&M Cost
Present Worth
Annual Cost
(9.3778)
SALVAGE VALUE (5)
Plant Structures
40 Years (50%)
Present Worth
Salvage Value
(0.1912)
PRESENT WORTH (PW)
Capital Cost
PW Annual Cost
PW Salvage Value
PW of Alternative
TOTAL ANNUAL
EQUIVALENT COSTS
(0.1066)
$17,490,000 $76,294,000 $96,347,000
18,360,000 11,377,000
172,176,000 106,691,000
0 (6) 1,7759,000
0 0
8,966,000
84,081,000
17,759,000
8,880,000
1,698,000
17,490,000
172,176,000
0
189,666,000
$20,218,000
76,294,000
106,691,000
0
182,985,000
$19,506,000
96,347,000
84,081,000
1,698,000
178,730,000
$19,053,000
ESTIMATED ANNUAL
EQUIVALENT COST
PER DRY TON (7)
$277
$267
$261
(1) Values based on a 20 year planning period, 8.625X federal discount rate, EPA construction cost
index base year 1973 large city, and consumer price index
(2) Based on Appendix G Table 5
(3) Based on Appendix G Table 7 and excludes sunk costs associated with incinerator section of
Solids Processing Building
(4) Based on Appendix G Table 1 and excludes sunk costs associated with incinerator section of
Solids Processing Building
(5) Based on EPA established guidelines and Appendix G Table 8
(6) Capital cost is for process equipment which has a design life of 20 years and no salvage value over the
planning period
(7) Based on an annual loading of 73,000 dry tons of sludge solids
6-12
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TABLE 6.2
SUMMARY OF ENVIRONMENTAL IMPACT POTENTIAL
Potential Environmental
Adverse Impacts
Air Impacts
Stack Emissions
Odor Emissions
Water Impacts
Surface Water
Groundwater
Land Impacts
Transportation
Land Use Conflicts
Nutrient Overloading
Landfill Capacity
Aesthetics
Incineration With
Ash Landfilling
X
X
Land
Application
X2
X2
X
X
X3
Combined
Incineration
Land Application
X
X
XL2
X
X
X3
X
X
1 Potential impact at landfill; leachate generation from ash residue.
2 Impacts are possible but extremely low because of guidelines and regulatory
controls.
3 Nutrient overloadings are remote if state guidelines are followed.
6-13
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The land application alternative has an indirect positive environ-
mental benefit related to nutrient loadings from non-point sources to the
Chesapeake Bay. With the land application of sludge, farmers are able to
partially avoid addition of commercial fertilizers. The commercial
fertilizers in general, provide "fast-release" of nutrients (including
nitrogen) into the soils, some of which are washed into the Bay. The "slow-
release" characteristics and soil conditioning effects of sludge nutrients
precludes some of the wash-off. As a result, the District may not have to
provide the same level of nutrient removal in wastewater treatment at Blue
Plains because of the benefit obtained from use of the sludge on farmlands.
The combination incineration/land application alternative is
necessarily a hybrid of the impacts associated with the other two. Since both
disposal techniques are included in the combination, the negative impacts of
both are included. However, the Degree of most of the impacts is reduced.
This evaluation did not place relative values on the environmental
impacts or on the degree to which impacts are additive or mitigated in the
combination alternative. It is judged that overall impacts of the combination
alternative are comparable to those associated with the other two.
6.4.3 Implementation Characteristics
Implementability depends upon three major factors, which in some
ways are interrelated: flexibility to meet current and variable future needs,
public acceptability, and management characteristics. Table 6.3, 6.4 and 6.5
summarize the characteristics of the alternatives.
The flexibility comparison in Table 6.3 indicates that the combina-
tion incineration/land application is best. The single method alternatives
(all incineration, all land application) are self limiting. The combination
alternative allows suitability or emphasizing of disposal methods. The land
application alternative provides superior flexibility in that (because of it's
low capital cost) it does not preclude switching to another method later. The
high capital cost of incineration will make switching difficult.
6-14
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The public acceptability comparison is inconclusive. All three
alternatives present concerns. In a way, the combined alternative combines
the problems associated with the other two. However, the degree of the
problem is mitigated somewhat by splitting the sludge into two disposal
methods.
Land application is now generally accepted by the public. However,
continued public acceptance will require strict adherence to regulations and
competent program management.
Public acceptability of incineration and Blue Plains has not been
tested. However, there is no doubt there will be at least some adverse public
reaction to potential emissions and to the visual impact of the incinerator
stacks.
EPA, to a great extent, represents the public. Therefore, EPA's
policy to encourage reuse of natural resources, is considered a part of the
public acceptability comparison. The public will be favorably inclined to
methods that are directed towards EPA's policy. The land application method
best meets the EPA goal; the incineration method is least effective; and the
combination alternative falls in between the other two.
The management characteristics summary on Table 6.5 indicates that
there may be management advantages to the District with total incineration.
The advantage lies principally in that the District would not have to rely on
outside contractors, or deal with the public beyond the plant site limits.
Nevertheless, all three alternatives do have both advantages and disadvantages
and the District has dealt successfully with most of these management
characteristics in the past.
The land application alternative, in addition to the characteristics
summarized in Table 6.5, also has the advantage that it may permit the
District to take "credit" for the reduced non-point nitrogen discharge from
lands tributary for the Chesapeake Bay (as was discussed in Section 6.4.2).
This credit could not be applied to an incineration alternative because it
6-15
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TABLE 6.3
FLEXIBILITY CHARACTERISTICS
Incineration with
Ash Landfilling
o Flexible to changing sludge quantities
o Inflexible to regulatory changes
(e.g. emission requirements, ash disposal
requirements).
o High capital costs commits District to
long-term use. Discourages future changes,
Agricultural Land
Application of
Dewatered Sludge
o Flexible to changing sludge quantities
o Inflexible to regulatory changes
(e.g. agricultural loading rates, aesthetic
requirements).
o Low capital cost permits District to change
to other methods later.
Combined Incineration/
Land Application
Flexible to changing sludge quantities and
characteristics. Allows switching between
disposal methods.
Flexible in meeting changing regulations by
switching between methods.
Intermediate capital costs discourages
switching off incineration.
6-16
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TABLE 6.4
PUBLIC ACCEPTABILITY CHARACTERISTICS
Incineration with
Ash Landfilling
Public concern with air pollutants and
with stacks (appearance).
Minimal use of natural resource (Public
and EPA concern).
Agricultural Land
Application of
Dewatered Sludge
o Local concern with site odors and truck
traffic.
o Maximize reuse of natural resource (Public
and EPA goal).
Combined Incineration/
Land Application
Local concern with site odors and truck
traffic (at land sites).
Public concern with air pollutants as with
stacks (appearance).
Moderate use of natural resource.
6-17
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Incineration with
Ash Landfilling
TABLE 6.5
MANAGEMENT CHARACTERISTICS
o Independent of outside contractors, etc.
o Must meet air pollution regulations.
o Must have ash disposal available.
o Has high operating, maintenance require-
ments .
Agricultural Land
Application of
Dewatered Sludge
Has reduced operating, maintenance require-
ments .
Must maintain site availability, site
permits.
Must maintain sludge quality.
Must work around seasonal limitations.
Must negotiate/renegotiate outside
contracts.
Has continuing high public visibility.
Combined Incineration/
Land Application
o
o
Provides District with options for dis-
posal.
Relies partially on outside contractors.
Must meet both air pollution and land
application regulations.
Has continuing high public visibility.
6-18
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would increase the use of commercial fertilizer and non-point nitrogen dis-
charge. If the land application nutrient control advantage can be demon-
strated, there is a possibility that the District could avoid some additional
nutrient control at Blue Plains. This would allow alternative uses for the
plant site in lieu of the intended denitrification facilities.
6.5 SUMMARY
The District will be managing and disposing of sludge in various ways.
It is committed to dispose of 87.5 DTPD through the MCCF and 123 DTPD by an
on-site FONSI'd composting facility. The sludge that is the subject of this
EIS could be disposed in various ways.
Three alternatives are viable. Land application is superior in that it
more fully meets EPA's reuse goals and has been shown by the District to be an
effective technique. Incineration has management advantages in that the
District will not be dependent upon outside contractors, municipalities,
public opinion land use. The combined incineration/land application alterna-
tive provides flexibility to the District in both for the present and for
meeting future changes.
6-19
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CHAPTER SEVEN
-------
CHAPTER 7
PREFERRED SLUDGE MANAGEMENT ALTERNATIVE AT BLUE PLAINS
7.1 INTRODUCTION
The history of sludge management at Blue Plains has ranged from the
earliest practice of land disposal, to sludge trenching, to drying, and to the
current practice of composting and land application at agricultural sites.
During the 1950's flash drying/incineration was used briefly followed by a
return to land application during the 1960's. However, land application at
that time was hampered by transportation difficulties and uneven product
quality. As a result, sludge was stockpiled and eventually removed through a
crash program starting in 1970.
From 1971 to the present, a succession of interim sludge management
methods have been used. Among these were trenching, drying on-site, land
application, composting, and chemical-fixing. Eventually, the methods
narrowed to just composting and land application on agricultural lands.
Currently, Blue Plains is composting 72 DTPD on-site, and transporting 40
DTPD to the MCCF for composting. The remaining 120 - 140 DTPD is applied to
agricultural lands. These disposal methods are a subject of the IMA which
places the responsibility on the District to manage an average of 323 DTPD.
Eventually, the MCCF will compost 87.5 DTPD and Blue Plains will compost 123
DTPD in the FONSI'd facility. Disposition of the remaining 200 DTPD is the
subject of this EIS.
Sludge disposal alternatives at Blue Plains have been subjected to
rigorous study during this EIS and previous studies. It has been confirmed
that the sludge is of high quality, with low metal concentrations. It is a
valuable material for both composting and land application.
7-1
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Since 1975, composting and land application have been, collectively, a
common denominator for sludge management. Difficulties have been encountered
ranging from storage to overflowing on site and odor problems at MCCF to
complaints at application sites. Current composting and land application have
alleviated the sludge storage problem on-site and upgrading at MCCF is
intended to alleviate odor complaints there. Problems at the land application
sites are intermittent with most resolved, generally, to the satisfaction of
all parties. However, the District government and user jurisdictions view
total recycling as fraught with regulatory and management implications. Long-
term dependence on this alternative is regarded as unwieldy.
7.2 SLUDGE MANAGEMENT ALTERNATIVES
7.2.1 Management Concerns
The following discussion summarizes the management implications of
each alternative:
Incineration: The District has already constructed a solids
processing building with space available for incinerators. The District would
not need to rely upon land availability, or markets outside its jurisdiction,
if incinerators were used. All personnel hired or contracted to operate the
incinerators would be solely reporting to the District management and there-
fore not subject to other authority.
Incineration is attractive and competitive because it minimizes
management variables. Major capital costs occur at the outset, followed by
lower operating costs over the life of the facility. This differs from the
other alternatives that rely upon recycling, where the costs are spread over a
number of years. For these reasons, the incineration option is attractive to
those responsible for plant operation.
Land Application: To implement this alternative, the District would
most likely continue the contractual arrangements already in place or
institute similar ones. The contractors or the District would have the
responsibility of maintaining land availability through obtaining permits and
7-2
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compliance with state and federal guidelines. Land application requires good
public relations on the part of the District or its contractor so that state
and local officials are agreeable to a continuing land application program.
The uncertainty of a continuing demand for this product is also a legitimate
concern, but one that appears to be lessening with time, as refinements in
application methods develop. The state management agencies are refining land
application through revisions to the regulations, as problems are recognized
and defined.
Successful operation of the land application program involves many
long-term management concerns, ranging from contract management through
scheduling of many interdependent operations. However, it has been a. success-
ful disposal method for the past several years, although requiring efforts on
the part of the contractors to alleviate problems. In addition, it has been
used at large cities throughout the Nation, e.g., Chicago.
Land Application/Incineration Combination: This alternative
incorporates the management concerns and advantages of both of the alterna-
tives. However, it presents a duplication of effort for operations that are
markedly different. That is, little similarity exists between the land
application and the incineration alternatives. Inasmuch as the District is
also managing a composting program, this combination of three disposal methods
requires a large management effort.
The combination alternative, incineration and land application, is
viewed as the least attractive from the management viewpoint because of the
complications of short and long-term costs, and the need for intensive manage-
ment.
Discussion: Management of sludge over the past few years has
depended heavily on reuse by land application and composting. Both compost-
ing, as conducted at MCCF, and land application, as demonstrated through the
contractual arrangements entered into by the District, have successfully
alleviated the sludge disposal problems experienced prior to the 1980's.
Although reuse is a continuing management concern, the District has
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demonstrated it can be done. Both composting and land application require
constant attention, but once instituted and with experience gained over time,
they have proven to be acceptable and successful alternatives.
The District government takes issue with a program that relies at
least partly on management outside their jurisdictional control. Since 1984,
the District of Columbia has been on a course towards developing independence
in sludge management. EPA acknowledges the District's desire to have total
management control over sludge disposal and that incineration represents that
control. Their major concern is a view that implementing and sustaining a
long-term land application program will be difficult. It requires a highly
developed infrastructure of contract management and inter-governmental
coordination and coordination. Although incineration requires sophisticated
technical management attention, it does not require the degree of inter-
governmental coordination and cooperation required by land application. EPA
recognizes that land application imposes different sludge management require-
ments than incineration. However, EPA also believes that successes achieved
thus far in the recycling effort can continue and be a long-term solution to
sludge management at Blue Plains.
7.2.2 Environmental Concerns
In keeping with EPA's municipal sludge management policy, which
states that recycling and reuse are the alternative of choice, (see page 5-3
for a description of this policy), the preferred alternative should maximize
recycling and reuse. This policy, combined with NEPA's purpose of fostering
good environmental decisions, leads towards a non-destructive alternative with
reuse as a major component.
Incineration: The incineration option carries little if any reuse
value and involves the loss of nutrients that are both of value to the soil
and potentially helpful in improving water quality in the Chesapeake Bay.
Nutrients returned to farmland replace some uses of inorganic fertilizers and
in that way nutrient runoff is reduced because organic nutrients tend to
7-4
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incorporate into the soil better than inorganic nutrients. The incinerator
ash, which must be landfilled, constitutes a further loss in resource because
it cannot be used again and because of its long-term land use commitment.
Incineration results in a two-thirds reduction in mass and a similar
reduction in truck traffic. Therefore, there will be less air pollution
compared to the other alternatives from hauling. However, this is offset to a
degree by the emissions from the incineration stacks. Additionally, the
incinerator stacks will significantly detract from the visual quality of the
District's horizon.
Land Application: Roughly 70,000 acres of land in Maryland and
Virginia are currently permitted for this use. The replacement of nutrients
in the farmland soils with sludge is a reuse method with few drawbacks. In
addition, the fertilizer and soil conditioner values of sludge reduce the use
of inorganic fertilizers and runoff of polluting nutrients to the Chesapeake
Bay. Reduction in fertilizer use not only saves on natural resources, but
also has secondary benefits of energy surveys.
The disadvantages of high volumes of truck traffic, and associated
noise and exhausts, are problems that can be mitigated through timing of
departures and arrivals, and by using alternative transportation modes where
feasible. The use of proper land application methods, which incorporate
sludge into the soil within a short period of time, will also mitigate odors.
These proper land application methods are being incorporated into state
environmental management programs, thus easing any environmental concerns
regarding impacts.
Land Application/Incineration Combination: This alternative
combines both the positive and the negative aspects of the other alternatives.
Reuse would be provided, but at a reduced rate. Air pollution from incinera-
tion would be reduced because the amounts would not exceed 100 DTPD, except
during peak conditions when 200 DTPD would be incinerated.
7-5
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However, truck traffic would remain high, requiring hauling of both
ash and sludge. Benefits to the Chesapeake Bay from reduced uses of inorganic
fertilizers would be less than half, because of the reduction in the
levels of high quality sludge applied to the land. Aesthetic considerations
would also be an issue because the proposed incinerators would still require
stacks.
7.2.3 Economic Concerns
Capital, operating, and present worth costs have been estimated for
each of these three major sludge management alternatives. Costs for each
alternative have been developed in Table 6.1 in Chapter 6. The following are
the key components of this table.
Land Application Incineration and Incineration
Alone Land Application Alone
1988 Estimated $17,490,000 $76,294,000 $96,347,000
Project Cost
Annual Operation & $18,360,000 $11,372,000 $ 8,966,000
Maintenance Cost
Total Annual $20,218,000 $19,325,000 $19,053,000
Equivalent Costs
Estimated Annual $277 $265 $261
Equivalent Cost
Per Dry Ton
The estimated total annual equivalent cost of the three alterna-
tives, considering the bounds of statistical error in engineering estimates,
are nearly equal.
The initial capital investment for construction of the incinerators
is considerably higher than land application. Conversely, land application
has a higher annual O&M cost. Lower annual operations and maintenance costs,
and the salvage values, of the incineration alternatives make them competitive
with land application on an annual equivalent cost basis.
7-6
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7.3 PREFERRED ALTERNATIVE
Under 40 CFR 1500.l(c), it is stated that "the NEPA process is intended
to help officials make decisions that are based upon understanding of environ-
mental consequences, and take actions that protect, restore, and enhance the
environment." While the incineration alternative has certain management
advantages, and it appears from the air emissions modeling that it will not
violate existing regulations, it does not meet NEPA's purpose as effectively
as does land application. However, the incinerator alternative would require
the management of a high level of sophisticated, on-site engineering tech-
nology.
There are potential secondary benefits to the Chesapeake Bay from land
application of sludge. Through reducing the amount of inorganic fertilizers,
soluble nutrients in runoff will be lessened. The organically bound
nutrients in sludge are released more slowly and are more readily bound in
soils than the nutrients from inorganic fertilizers. In addition, potential
pollution from fertilizer manufacturing will be reduced along with a reduction
in raw materials usage.
This EIS applies to the disposition of 200 DTPD, with peaks occasionally
reaching as high as 384 DTPD. However, the peak level may not be reached
until as late as 2010. The FONSI'd in-vessel composting on-site will be
increased to accommodate some of the additional sludge, up to at least 123
DTPD. This will leave substantial amounts for disposal. However, the period
of time until that level is reached can be used to develop and refine the
alternative selected.
Current reliance on reuse by composting and land application is
consistent with the generally successful application of these techniques in
the late 1970's and early 1980's. As the regulatory agencies refine their
guidelines and the contractors increase public awareness, the problems have
eased. Although land application appears to cost slightly more than inciner-
ation, that disadvantage is somewhat offset by the value of nutrients returned
to the land, and the benefits to water quality from lower nutrient concentra-
tions in runoff that results from inorganic fertilizers.
7-7
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From the conclusion of this EIS, EPA has determined that land applica-
tion, in combination with FONSI'd composting, as shown by Figures 6.1 and 6.5,
is the preferred alternative. Land application of roughly 200 DTPD will be
required throughout the year. The occasional peak will be offset by the
equally occasional lower-than-average quantity. The management scheme in
place is currently operating efficiently and in time this already successful
course can be improved upon.
The preferred alternative is supported by a number of management and
environmental considerations. Each of these has been discussed previously in
the EIS but needs to be again emphasized in support of the preferred alterna-
tive.
7.3.1 Management Benefits
A management infrastructure for reuse of sludge solids is already in
place in the Washington, D.C. area. The Washington Suburban Sanitary
Commission (WSSC) through its MCCF facility is successfully marketing its
compost materials. This facility will be expanded and along with a new
in-vessel facility at Blue Plains will produce a high quality compost product
that is in demand as a soil conditioner.
Lands permitted for sludge application in Maryland and Virginia are
abundant. As indicated in Chapter 2 (see Table 2.5) there are approximately
70,000 acres of permitted land available for application of Blue Plains sludge
under the present contract management program. This availability of land
substantially exceeds the land required to dispose of the average 200 DTPY
over the next 20 years.
The District and its contractors have accumulated valuable opera-
tional experience with land application. This experience is substantial and
can be utilized to improve and enhance the success of this technology.
Although occasional public relations problems associated with land applica-
tion have arisen, they can be handled by contractors with a minimum of impact
to users and the District because of increased sensitivity to this need. It
is anticipated that public acceptance of this practice will continue to grow.
7-8
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Land application is probably the least complicated operation of any
of the alternatives under consideration. However, land application still
requires good planning, careful field operations and a keen awareness of what
is required to gain and maintain public support and awareness. It has been in
practice at Blue Plains over the past several years. It is an alternative
that is economically competitive with other alternative sludge disposal
techniques; ample land has been consistently available and permitted to
receive sludge; and it is the simplest alternative to operate.
7.3.2 Environmental Benefits
There are numerous environmental benefits from the use of land
application. These include the return of nutrients to the land as a valuable
commodity rather than their loss through a non-recycling, disposal alterna-
tive. Sludge can be used to replace some of the uses of inorganic fertil-
izers, with the accrued environmental benefits and the reduction in surface
and groundwater pollution potential from inorganic fertilizers.
The reduction of nutrients to the Bay is an overall goal of the
Chesapeake Bay program. Using sludge as a supplement or even replacement for
commercial inorganic fertilizers can assist in the effort to clean up the Bay.
Land application will also assist in preserving the visual integrity
of the Washington, D.C. area. The D.C. area has always attempted to maintain
its low profile skyline and, with few exceptions, this has been successfully
maintained. The proposed incinerator stacks would be approximately 225 ft. in
height and would clearly penetrate the low profile horizon.
Emissions from the stacks would be eliminated as a source of air
pollution in the area. They would be somewhat replaced by diffused mobile
sources from the trucks that would transport the sludge material to land
application sites throughout the region.
7-9
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7.4 CONCLUSIONS
o The preferred alternative is land application of all wastewater
sludge generated at Blue Plains. The District should continue its
current practice of land application.
o There is contractor interest in land application and sufficient
permitted lands are available.
o Land application provides for recycling and utilization of a
valuable commodity.
o Land application is economically competitive with other
alternatives.
o Land application can be managed with relative ease provided there is
good planning and implementation.
o Land application will not impact upon any of the current space
utilization problems at Blue Plains.
o Land application will have the least environmental impacts, through
recycling an important source of nutrients, comply with goals for
protection of the Chesapeake Bay, reduce air emission in the area
and eliminate visual impacts on the D.C. skyline.
o EPA acknowledges that the preferred alternative does not provide the
autonomous control over sludge management that the District govern-
ment believes is necessary.
7-10
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REFERENCES
1. Camp Dresser & McKee, "District of Columbia Final Report Sludge,
Solid Waste, Co-Disposal Study," July 1984.
2. Camp Dresser & McKee, "District of Columbia Supplemental Report
Sludge, Solid Waste, Co-Disposal Study", July 1984.
3. Engineering Science, "Dewatering, Composting and Incineration
System Evaluations for Sludge Management at Blue Plains Wastewater
Treatment Plant, Volume II Technical Data", February 1985.
4. Engineering Science, "Dewatering, Composting and Incinerator
System Evaluations for Sludge Management at District of Columbia
Wastewater Treatment Plant at Blue Plains, Volume I Technical
Report", April 1985.
5. Engineering Science, "Preliminary Incineration System Concept
Designs for District of Columbia Wastewater Treatment Plant at
Blue Plains (Task II-10B)", December 1985.
6. Engineering Science, "Report on the Plate and Frame Filter Press
Sludge Dewatering Test Program (Task II-12B)", June 1986.
7. Engineering Science, "Report on the Sludge Sampling and
Incineration Characterization Program (Tasks II-12A and 12C)",
June 1986.
8. Engineering Science, "Report on the Centrifuge Sludge Dewatering
Test Program (Task II-12C)", August 1986.
9. Engineering Science, "Report on the late and Frame Filter Press
Sludge Dewatering Test Program (Task II-12B)", August 1986.
10. Engineering Science, "Report on the Sludge Sampling and
Incineration Characterization Program (Tasks II-12A and 12C)",
August 1986.
11. Engineering Science, "Report on the Sludge Compostability Test
Program (Task II-12D)", September 1986.
12. Engineering Science, "Report on the High Pressure Sludge Pumping
T«st Program (Task II-12E), September 1986.
13. Engineering Science, "Final Incineration System Concept Designs
for the District of Columbia Wastewater Treatment Plant at Blue
Plains (Task II-10F), October 1986. (Preliminary)
14. Engineering Science, "Air Emission Inventory" (Task 11-13),
October, 1986.
R-l
-------
15. Engineering Science, "Air Quality Modeling Analysis for Sludge
Incineration at the District of Columbia Wastewater Treatment Plant
at Blue Plains (Task 11-14G), December, 1986.
16. Engineering Science, "Air Pollutant Emission Factors for Sludge
Incineration (Task 11-11), September, 1986.
17. Grumpier and Rubin, Office of Water Regulations and Standards US
EPA, "Development of Federal Management Regulations Under 405(d)",
Proceedings of the National Conference on Municipal Treatment Plant
Sludge Management, May 1986.
18. U.S. Environmental Protection Agency, "Environmental Regulations
and Technology, Use and Disposal of Municipal Wastewater Sludge",
September 1984, Technology Transfer EPA 625/10-84-003.
19. U.S. Environmental Protection Agency, "Seminar Publication
Composting of Municipal Wastewater Sludges", August 1985,
Technology Transfer EPA 625/4-85-014.
20. U.S. Environmental Protection Agency, "Pathogen Risk Assessment
Feasibility Study", November 1985, WH-585.
21. U.S. Environmental Protection Agency, "Process Design Manual
Sludge Treatment and Disposal", September 1979, Technology
Transfer, EPA 625/1-79-011.
22. U.S. Environmental Protection Agency, "Process Design Manual
Municipal Sludge Landfills", October 1978,, Technology Transfer,
EPA 625/1-78-010.
23. U.S. Environmental Protection Agency and U.S. Department of
Agriculture, "Manual for Composting Sewage Sludge by the Beltsville
- Aerated Pile Method", May 1980, EPA 600/8-80-022.
24. Wilson, Agricultural Research Service, U.S. Department of Agri-
culture, "Forced Aeration Composting", Water Science Technology.
Volume 15, 1983.
25. U.S. Environmental Protection Agency, "Handbook Estimating Sludge
Management Costs", October 1985, Technology Transfer,
EPA/625/6-85/010.
26. U.S. Environmental Protection Agency, "Process Design Manual Land
Application of Municipal Sludge", October 1983, Technology Transfer,
EPA-625/1-83-016.
27. Personal Communications - Messrs. Thomas, and Laden, Riddle
Department of Public Works, District of Columbia.
28. Personal Communications - Mr. Murray, Montgomery County Composting
Facility, Washington Suburban Sanitary Commission.
R-2
-------
29. Personal Communications * Mr. Pepperman, Envlro-Gro Technologies,
Baltimore, Maryland.
30. Personal Communications - Mr. O'Neal, Ad + Soil, Inc., West
Chester, Pennsylvania.
31. Personal Communications - Mr. Campbell, Bio Gro Systems,
Annapolis, Maryland.
32. Personal Communications - Ms. Knight, Eastern Research Group,
Inc., Arlington, Massachusetts.
33. Duedall, I.W., H.B. O'Connors and B. Irwin, "Fate of Wastewater
Sludge in the New York Bight Apex", Journal of the Water Pollution
Control Federation. Vol. 47(11), pp. 2702-2706, 1975.
34. National Academy of Sciences, "Assessing Potential Ocean
Pollutants", 1975.
35. Rohatgi, N., and K.Y. Chen, "Transport of Trace Metals by Suspended
Particulates on Mixing with Seawater", Journal WPCF. Vol. 47(9),
pp. 2298-2316, 1975.
36. Rowe, G. T., "The Effects of Pollution on the Dynamics of the
Benthos of the New York Bight", Thalassla Juposlavica. 7(1):
353-359, 1971.
37. U.S. Department of Commerce, Ocean Dumping in the New York Bight.
Marine Ecosystems Analysis Program, 1975.
38. U.S. Environmental Protection Agency, "Ocean Disposal of
Barge-delivered Liquid and Solid Wastes from U.S. Coastal Cities",
golid Was£e Management Office Publication SW-19c, 1971.
39. U.S. Environmental Protection Agency, "Environmental Impact
Statement on the Ocean Dumping of Sewage Sludge in the New York
Bight", September, 1978.
40. U.S. Environmental Protection Agency, NOAA, "Environmental Effects
of Sewage Sludge at the Philadelphia Dumping Site", June 12, 1979.
41. Bezdek, H. F., and A. F. Carlucci "Surface Concentration of Marine
Bacteria", Limnol Oceanography. 17:566-569, 1972.
42. Hoffman, E. J., and R. A. Duce, "The Organic Carbon Content of
Marine Aerosols Collected on Bermuda", J. Geophys. Res. 79, 1974.
43. Odum, H. T., "Analysis of Diurnal Oxygen Curves for the Assay of
Reaeration Rates and Metabolism in Polluted Marine Bays,
Proceedings of the First International Conference on Waste Disposal
in the Marine Environment", 1960.
44. WeHock, C. E., "Epidemiology of Q Fever in the Urban East Bay
Area", Calif. Health 18, 1960.
R-3
-------
45. Chen, K. Y., "Trace Metals in Wastewater Effluents" Journal of the
Water Pollution Control Federation. Vol. 42(12); pp. 2663-2675,
1974.
46. Blue Plains Intermunicipal Agreement, September 1985.
47. EcolSciences, "Incineration and Composting Technology Inventory",
August, 1986.
48. U.S. Environmental Protection Agency, "Fate of Priority Pollutants
in Publicly Owned Treatment Works", Interim Report, EPA
440/1-80-30, October 1980.
49. U.S. Environmental Protection Agency, "Report to Congress on the
Discharges of Hazardous Waste to Publicly Owned Treatment Works",
EPA 530/SW-86-004, February 1986.
50. Biocvcle. "Sewage Sludge Composting Maintains Momentum", November-
December, 1986.
51. U.S. Environmental Protection Agency, Technology Transfer, Seminar
Publication, "Municipal Wastewater Sludge Combustion Technology",
EPA 625/4-85/015, September 1985.
52. Personal Communications - Mr. Gossett, Compost Systems Company,
Cincinnati, Ohio.
53. Personal Communications - Mr. Laurenson, American BioTech Inc.,
Jacksonville, Florida.
54. Clark, C.S., et al., "Biological Health Risks Associated with the
Composting of Wastewater Treatment Plant Sludge", Journal Water
Pollution Control Federation. 56, 1269, 1984.
55. Clark, C.S., "Potential aud Actual Biological Related Health Risks
of Wastewater Industry Employment". Journal Water Pollution
Cpntrol Federation. 59, 999, 1987.
56. McLeod, R. V., and Hegg, R. 0., "Pasture Runoff Water Quality from
Application of Inorganic and Organic Nitrogen Sources", Journal
Environmental Quality. Vol. 13, No. 1, 1984.
R-4
-------
APPENDICES
APPENDIX A - LOCAL, STATE AND FEDERAL REGULATIONS
APPENDIX B - PREVENTION OF SIGNIFICANT
DETERIORATION (PSD) CATEGORIES,
MAJOR SOURCE DEFINITION
APPENDIX C - LIST OF PRIORITY POLLUTANTS
APPENDIX D - SURVEY: FACILITIES COMPOSTING
MUNICIPAL SLUDGE IN THE UNITED STATES
APPENDIX E - SURVEY: FACILITIES INCINERATING
MUNICIPAL SLUDGE IN THE UNITED STATES
APPENDIX F - SUMMARY AND CONCLUSIONS: INCINERATION
AND COMPOSTING TECHNOLOGY INVENTORY,
ECOLSCIENCES, INC., AUGUST, 1986
APPENDIX G - SOLIDS MANAGEMENT ALTERNATIVES
COST ANALYSIS VALUES
APPENDIX H - DESIGN YEAR SLUDGE QUANTITIES
SUBJECT TO EIS (GRAPH OF ANNUAL AVERAGE,
PEAK, AND NON-PEAK MONTH SLUDGE QUANTITIES
APPENDIX I - ADDITIONAL CONSIDERATIONS
REGARDING LAND APPLICATION OF
SEWAGE SLUDGE IN VIRGINIA AND MARYLAND
-------
-------
APPENDIX A - LOCAL, STATE AND FEDERAL REGULATIONS
-------
APPENDIX A
LOCAL, STATE AND FEDERAL REGULATIONS
FEDERAL REGULATIONS
Clean Water Act and Federal Water Pollution Control Act
o Authorizes EPA to issue comprehensive sewage sludge management
guidelines and regulations.
o Authorizes the National Pollutant Discharge Elimination System
(NPDES).
o Authorizes Federal funding for eligible costs of municipal WWTP's
sludge treatment and disposition facilities.
Resource Conservation and Recovery Act
o Requires regulations for the safe disposal of hazardous and
nonhazardous waste.
Clean Air Act
o Authorizes the development of State Implementation Plans to meet
Federal ambient air quality standards.
o Authorizes regulations for the control of hazardous air pollutants
and new source performance standards.
Toxic Substances Control Act
o - Requires coordination with the Clean Air and Clean Water Acts to
restrict disposal of hazardous wastes (PCB from sludge).
National Environmental Policy Act
o Requires EIS's to be performed if potential adverse impacts are
suspected for a new or modified sludge disposition facility.
Safe Drinking Water Act
o Requires coordination of CWA and RCRA to protect drinking water
from contamination.
Marine Protection, Research and Sanctuaries Act
o Regulates ocean dumping of sewage sludge and establishes a schedule
for phasing out ocean disposal in favor of other land-based
methodologies.
A-l
-------
40 CFR, Part 761, PCB Regulations
o Regulates all sludges containing more than 50 mg/kg.
40 CFR, Parts 220-228 - Ocean Discharge Regulations
o Regulates the discharge of sludge from barges or other vessels.
40 CFR, Part 60, New Sources of Air Emissions
o Sets standards for emissions from sludge incineration operations at
rates above 1,000 kg/day.
40 CFR, Part 61, Mercury Regulations
o Regulates the incineration and heat drying of sludge.
40 CFR, Part 257, Hazardous Waste Regulations
o Sets standards for cadmium, PCB's and pathogenic organisms for land
application, landfills and storage lagoons.
40 CFR, Part 261, Appendix II - Extraction Procedure Toxicity Regulations
o Determine whether sludges are hazardous wastes.
STATE REGULATIONS
Virginia
Virginia Solid and Hazardous Waste Management Law
o Regulates the collection, handling and disposal of solid and
.hazardous wastes.
o Establishes the waste management permitting system and
justification for permit revocation.
Virginia Solid Waste Regulations
o Prohibits ocean disposal of solid waste, with the exception of
certain inert solid waste (concrete, rubble, ash, etc.).
o Outlines accepted methods of solid waste disposal including
sanitary landfills, incinerators and acceptable new and unique
methods.
o Prohibits disposal of hazardous wastes in sanitary landfills except
as permitted.
o Establishes guidelines of sanitary landfill and incinerator
operating procedures.
A-2
-------
Virginia Draft Revisions to the Sewerage Regulations, May 16, 1986
o Sets the standards for sludge testing to determine sludge
characteristics.
o Requires sludge treatment which significantly reduces pathogen
content, volatile solids content and potential for odor problems.
o Prohibits public access and excavation of sludge amended land for
twelve months and grazing or feeding of green forage from these
areas for 30 days and 60 days for livestock and dairy animals
respectively.
o Establishes standards for emergency, temporary and routine storage
of sludge.
o Establishes guidelines for land application siting, including a 750
foot buffer zone (some exceptions), prohibition of areas within the
100-year flood/wave area and conformance with local zoning regula-
tions.
o Supernatant/leachate may be returned to the treatment plant,
incorporated with sludge and land applied or treated and land
applied separately.
o Sludge used for agricultural purposes must be treated by a process
to significantly reduce pathogens.
o Agricultural soils must be at least IS inches deep and the sludge/
soil moisture must have a pH of 6.5 or greater if the sludge
cadmium content is greater or equal to 2 ing/kg.
o Slopes for agricultural utilization should not exceed 12 percent
- unless incorporated within 48 hours.
o Agricultural application rates shall not exceed 15 dry tons per
acre per year, 10% of maximum cumulative loading of any metals the
maximum CCE loading rate, or the previous years' sludge nitrogen
mineralization rates for frequently used areas.
o Groundwater and surface water monitoring may be required for
frequent agronomic rates or for application with cumulative metal
loadings above 50% of the maximum allowed.
Maryland
Maryland Refuse Disposal Regulations
o Defines solid waste as not containing solids or dissolved materials
in domestic sewage.
o Regulates the design and operation of sanitary landfills.
A-3
-------
Maryland Proposed Regulations under COMAR 10.17.10, Sewage Sludge
o $100,000 set aside in Sludge Utilization Fund for mitigation of
adverse environmental impacts of sewage sludge impacts.
o Requires permits for collection, handling, burning, storage, treat-
ment, land application, disposal or transportation of sewage
sludge, treated sewage sludge or any product containing these
materials (with exceptions).
o All sludge must be treated by a process to significantly or further
reduce pathogens including aerobic digestion, air drying, anaerobic
digestion, composting, heat drying, heat treatment thermophilic
aerobic digestion or other methods acceptable to the Department.
o Groundwater and soils monitoring must take place in areas used for
sludge storage.
o Methods and calculations are set to determine maximum sludge
loading rates in a land application program.
o Only Class I sewage sludge may be applied to agricultural land.
o Application on the land may not exceed limits for metals set in the
regulations.
o After January 1, 1987 the annual application of cadmium may not
exceed .04 pounds per acre.
o Crops for direct human consumption may not be grown in a sludge
amended area for three years.
o Incineration of sludge must take place in a manner which does not
cause environmental degradation, meets air quality standards and
must be 1,000 feet from the nearest off-site inhabited building
(possible exceptions).
o Sludge to be incinerated must be tested for content by Department
standards.
o Sludge placed in sanitary landfills may not contain free liquids.
LOCAL REGULATIONS
Montgomery County, Maryland
o Landfilling prohibited for municipal sludge.
o No sludge trenching permitted.
o Solid waste plan sets composting and thermal processing as the
goal.
A-4
-------
Prince Georges County, Maryland
o Contents of sludge, compose, etc. tested and regulated.
o Haul roads and sices must be approved if disposal is not under
contract with WSSC.
o Methods of land application must be approved.
o Trucks used for sludge transport must be covered,
o No current sludge incineration regulations.
Fairfax County, Virginia
o No land application permitted within the Occoquan River watershed.
o No other direct County regulations; State regulations apply.
Washington, D.C.
o National Capital Planning Commission must approve the project if it
alters or significantly impacts the District's Comprehensive Plan.
o Home Rule Act requires Advisory Neighborhood Commission review of
any proposed alternative.
o District of Columbia, Department of Consumer and Regulatory Affairs
(DCRA) regulates emissions of particulates from sewage sludge
incinerators.
o DCRA regulates visible emissions from smokestacks and emissions of
odors.
A-5
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APPENDIX B - PREVENTION OF SIGNIFICANT
DETERIORATION (PSD) CATEGORIES,
MAJOR SOURCE DEFINITION
-------
APPENDIX B
PSD SOURCE CATEGORIES
1. Fossil fuel-fired steam electric plants of more than 250 million BTU/hr.
heat input
2. Coal cleaning plants (with thermal dryers)
3. Kraft pulp mills
4. Portland cement plants
5. Primary zinc smelters
6. Iron and steel mill plants
7. Primary aluminum ore reduction plants
8. Primary copper smelters
9. Municipal incinerators capable of charging more than 250 tons of refuse
per day
10. Hydrofluoric acid plants
11. Sulfuric acid plants
12. Nitric acid plants
13. Petroleum refineries
14. Lime plants
15. Phosphate rock processing plants
16. Coke oven batteries
17. Sulfur recovery plants
18. Carbon black plants (furnace process)
19. Primary lead smelters
20. Fuel conversion plants
21. Sintering plants
22. Secondary metal production plants
23. Chemical process plants
24. Fossil fuel boilers (or combinations thereof) totaling more than 250
million/BTU/hr. heat input
25. Petroleum storage and transfer units with a total storage capacity
exceeding 300,000 barrels
26. Taconite ore processing plants
27. Glass fiber processing plants
28. Charcoal production plants
These source categories are listed in both the Clean Air Act and PSD
regulations. A source is considered major if:
(1) listed in PSD source category with emissions of any criteria
pollutant greater than 100 tons per year.
(2) not listed in one of these categories with emissions of any
criteria pollutant exceeding 250 tons per year.
(3) it is a source which is located within or impacts a nonattainment
area (NA) and emits 100 tons per year or more of any pollutant for
which the area has been designated as NA.
Source: Engineering Science, Task 11-13, October 1986.
B-l
-------
APPENDIX C - LIST OF PRIORITY POLLUTANTS
-------
APPENDIX C
LIST OF EPA PRIORITY POLLUTANTS (1)
(Listed by EPA Numerical Order)
1 acenc >hthene
2 acrolein
3 acrylonitrile
4 benzene
5 benzidine
6 carbon tetrachloride
7 chlorobenzene
8 1,2,4-trichlorobenzene
9 hexachlorobenzene
10 1,2-dichloroethane
11 1,1,1-trichloroethane
12 hexachloroethane
13 1,1-dichloroethane
14 1,1,2-trichloroethane
15 1,1,2,2-tetrachloroethane
16 chloroethane
17 bis(chloromethyl)ether (a)
18 bis(2-chloroethyl)ether
19 2-chloroethyl vinyl ether
20 2-chloronaphthalene
21 2,4,6-trichlorophenol
22 parachlorometacresol
23 chloroform
24 2-chlorophenol
25 1,2-dichlorobenzene
26 1,3-dichlorobenzene
27 1,4-dichlorobenzene
28 ' 3,3-dichlorobenzidine
29 1,1-dichloroethylene
30 1,2-trans-dichloroethylene
31 2,4-dichlorophenol
32 1,2-dichloropropane
33 1,3-dichloropropylene
34 2,4-dimethylphenol
35 2,4-dinitrotoluene
36 2,6-dinitrotoluene
37 1,2-diphenylhydrazine
38 ethylbenzene
39 fluoranthene
40 4-chlorophenyl phenyl ether
41 4-bromophenyl phenyl ether
42 bis-(2-chloroisopropyl)ether
(a) Deleted February 24, 1981.
(1) Priority Pollutants - Toxic with respect to carcinogenicity,
mutagenicity, teratogenicity, and/or persistence.
C-l
-------
A3 bis(2-chloroethoxy)methane
44 methylene chloride
45 methyl chloride
46 methyl bromide
47 bromoform
48 dichlorobromomethane
49 trichlorofluoromethane (a)
50 dichlorodifluoromethane (a)
51 chlorodibromomethane
52 hexachlorobutadiene
53 hexachlorocyclopentadiene
54 isophorone
55 naphthalene
56 nitrobenzene
57 2-nitrophenol
58 4-nitrophenol
59 2,4-dinitrophenol
60 4,6-dinitro-o-cresol
61 N-nitrosodimethylamine
62 N-nitrosodiphenylamine
63 N-nitrosodi-n-propylamine
64 pentachlorophenol
65 phenol
66 bis(2-ethylhexyl)phthalate
67 butyl benzyl phthalate
68 di-n-butyl phthalate
69 di-n-octyl phthalate
70 dimethyl phthalate
71 benzo(a)anthracene
72 benzo(a)pyrene
73 3,4-benzofluoranthene
74 benzo(k)fluoranthene
75 chrysene
76 acenaphthylene
77 anthracene
78 benzo(ghi)perylene
79 fluorene
80 phenanthrene
81 dibenzo(a,h)anthracene
82 indeno(l,2,3-cd)pyrene
83 pyrene
84 tetrachloroethylene
85 toluene
86 trichloroethylene
87 vinyl chloride
(a) Deleted February 3, 1981.
C-2
-------
89 aldrin
90 dieldrin
91 chlordane
92 4,4'-DDT
93 4,4'-DDE
94 4,4'-ODD
95 alpha-endosulfan
96 beta-endosulfan
97 endosulfan sulfate
98 endrin
99 endrin aldehyde
100 heptachlor
101 heptachlor epoxide
102 alpha-BHC
103 beta-BHC
104 gamma-BHC
105 delta-BHC
106 PCB-1242
107 PCB-1254
108 PCB-1221
109 PCB-1232
110 PCB-1248
111 PCB-1260
112 PCB-1016
113 toxaphene
114 antimony
115 arsenic
116 asbestos
117 beryllium
118 cadmium
119 chromium
120 copper
121 cyanide
122 lead
123 mercury
124 nickel
125 selenium
126 silver
127 thallium
128 zinc
129 2,3,7,8-tetrachlorodibenzo-p-dioxin
C-3
-------
APPENDIX D - SURVEY: FACILITIES COMPOSTING
MUNICIPAL SLUDGE IN THE UNITED STATES
-------
APPENDIX D
FACILITIES COMPOSTING MUNICIPAL
SLUDGE IN THE U.S. - A SUMMARY
Number of Facilities
OPERATIONAL :
In-Vessel
Aerated Static Pile
Windrow
Aerated Windrow
Vermicomposting
Not Specified
8
52.5
20.5
6
1
1
(1)
TOTAL OPERATIONAL: 89
UNDER CONSTRUCTION:
In-Vessel 11
Aerated Static Pile 8
Windrow 2
Aerated Windrow 1
TOTAL UNDER CONSTRUCTION:22
PLANNING, DESIGN, BID:
In-Vessel 11
Aerated Static Pile 10
Windrow 3
Aerated Windrow 3
Not Specified 1
TOTAL PLANNING, DESIGN, BID:28
PILOTS:
In-Vessel 4
(Also counted in "Consideration"
Category)
Aerated Static Pile 5
Windrow 3
Aerated Windrow 1
Vermicomposting 1
TOTAL PILOTS:14
CONSIDERATION:
In-Vessel 14
Aerated Static Pile 5.5
Windrow 2
Aerated Windrow .5
Not Specified 5
TOTAL CONSIDERATION:27
SURVEY TOTALS:
Operational 89
Under Construction 22
Planning, Design, Bid 28
Pilots 14 (4 in Consideration)
Consideration 27
Not Specified 2
TOTAL:'178
(1) Decimal points indicate that facilities utilize more than 1 technology.
Source: Biocycle, November-December, 1986.
D-l
-------
APPENDIX D
FACILITIES COMPOSTING
MUNICIPAL SLUDGE IN THE U.S.
State
1. Alabama
2. Alaska
3. Arizona
4. Arkansas
5. California
6. Colorado
7. Connecticut
8. Delaware
9. Florida
Plant Name
1.
1.
1.
Do than City
Juneau
Phoenix: 23rd St. Plant
Status
Operational (10/29/86)
Design
Operational (by Western
Agricultural Products)
Type
In-Vessel (Taulman-Ueiss)
In-Vessel (Taulman-Weiss)
Windrow
Sludge Volume
dry ton/day
(unless noted)
6.75 (Design)
3-4
None
I.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
1.
2.
3.
4.
5.
1.
2.
3.
4.
5.
6.
7.
1.
2.
3.
1.
2.
3.
4.
5.
Chino
Fallbrook
Hayvard
Los Alisos: El Toro
Los Angeles County
JWPCP
North San Diego County
Oakland: East Bay Mud
Oxnard
San Diego
Santa Barbara
City of S. San Francisco
Simi Valley
Denver Metro
Ft. Collins
Greeley
Longmont
Wheatridge
Bristol
Greenwich
Hartford
Killingly
New London
Norwich
Wlndham
Middletown/Odessa
Seaford
Wilmington
Broward Cty. Streets &
Highway Div.
Collier Cty.
Cooper City Utilities
Fort Lauderdale
Hlllsborough Cty.
Utilities
Operational (by Garden
Mate)
Pilot
Operational (by Mlltona
Brothers)
Operational
Operational
Consideration
Operational
Design
Planning
Planning
Operational
Design
Operational
Bid stage
Consideration
Pilot
Operational
Construction
Operational
Planning
Consideration (short-
term pilot w/Intl.
Processing Systems:
IPS)
Consideration (short-
term pilot w/IPS)
Consideration (short-
term pilot w/IPS)
Consideration (short-
term pilot w/IPS)
Construction
Construction
Operational (Co-
composting)
Operational
Consideration
Planning
Construction
Consideration
A-SP (1)
Vernicomposting
Windrow
A-SP
Windrow
Air drying w/wlndrow
composting)
A-SP
In-Vessel w/windrow curing
(Fair field)
Windrow
In-Vessel
Windrow
Air drying w/wlndrow
composting
Aerated windrow
Aerated windrow
A-SP or aerated windrow
A-SP
Windrow
A-SP
A-SP
In-Vessel (Paygro)
In-Vessel
In-Vessel
In-Vessel
In-Vessel
In-Vessel
A-SP
In-Vessel (Falrfleld)
Windrow
Windrow
Windrow
In-Vessel (Purac)
In-Vessel
1
.25
300
52 (max. size)
60
30
25
10
10
11
73
6
10
3/month
10
2500 cu.
yd./yr.
33
2
5-6
.5
1.7
.5
6
70
7.93
30
35
(1) A-SP - Aerated Static Pile.
D-2
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APPENDIX D (Cont'd.)
FACILITIES COMPOSTING
MUNICIPAL SLUDGE IN THE U.S.
10.
11.
12.
13.
14.
15.
16.
17.
IB.
19.
State
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Plant Name
6. Jacksonville: Buckman
Plant
7. Kissimee: Martin St.
Plant
8. Lee County
9. Loxahatchee River Disc.
10. Manatee Cty. Southeast
11. Mandarin Cty. Utilities
12. Margate
13. Meadowwood Utilities
14. Orange County
15. Orlando
16. Plant City
17. Reedy Creek
18. Sarasota
1. Plains
2. Northeast Clayton
County WPCP
1. Waimanalo WWTP (Oahu)
None
None
1. Blucher Poole WWTP
(Bloomington)
None
1. Mission (Johnson Cty.)
2. Topeka: Oakland WWTP
3. Wichita: WPCP #1 4 #2
1. West Hickam Creek WWTP
(Nicholsville)
None
1 . Bangor
2. Bar Harbor
3. Gardiner
4. Kennebunkport
5. Old Orchard Beach
(& Saco)
6. Old Town (& Orono)
7. Portland Water Dist.
8. Scarborough San. Dist.
9. South Portland
10. Yarmouth
Status
Operational
Operational
Consideration
Consideration
Consideration
Construction
Planning
Operational
Planning
Consideration
Construction
Construction
Consideration
(Privatized regional
facility-Green Grow
Industries)
Operational
Operational (Private
arrangement w/nursery)
Planned (1990)
Operational
Pilot (Full-scale under
consideration)
Operational
Operational
Operational
Operational
Operational
Operational
Operational
Operational
Operational
Operational
Operational
Operational
Operational
Type
A-SP
Vermicomposting
A-SP
Windrow
Windrow
A-SP
A-SP
In-Vessel (Taulman-Welss)
In-Vessel (Purac)
A-SP
In-Vessel (Taulman)
Windrow
A-SP
Windrow & A-SP
Windrow
Windrow
Windrow
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
Sludge Volume
dry ton/day
(unless noted)
2
16
4
2-3
3
5
6
9
10 (pilot)
200 (design)
1 (operational)
3 (design)
5
2-3
16-18
10
4.5-5
(5 days/wk.)
3500 cu.
yd./yr.
(3 2000 cu.
yd./yr.
1.5
@1
160-170 cu.
yd./wk.
350 cu.
yd. /month
16.2
30 cu. yd./wk.
5
.25-. 5
D-3
-------
APPENDIX D (Cont'd.)
FACILITIES COMPOSTING
MUKICIPAL SLUDGE IN THE U.S.
State
20. Maryland
21. Massachusetts
22. Michigan
23. Minnesota
24. Mississippi
25. Missouri
26 . Montana
27. Nebraska
28. Nevada
Plant Name
1. Aberdeen
2. Baltimore: Back River
3. Cambridge
4. Elkton
5. Havre de Grace
6. Montgomery Cty.
7. Parkway WWTP (WSSC)
8. Perryville
1. Amherst
2. Barre
3. Billerica
4. Boston
5 . Bridgewater
6 . Concord
7. Deer Island (MWRA)
8. Gloucester
9. Haverhill
10. Leicester
11. Leominster
12. Mansfield
13. Marlboro
14. Nantucket
15. Orleans
16. Pepperell
17. Somerset
18. Southbridge
19. SwampscotC
20. Wes thorough
21. Williamstown/Hoosac
1. Battle Creek
2. Mackinac Island
1. Pine River
None
None
1. Mlssoula
1. Beatrice
2. Grand Island
3. Kearney
It. Omaha: Paplllion Creek
WPCP
5. Omaha: Missouri River
1. Las Vegas
2. Clark County San.
District
Status
Design
Construction
Operational
Operational
Construction
Operational
Consideration
Operational
Design
Design
Consideration (Long-
term)
Planning
Operational
Pilot
Planning
Design
Construction
Bid stage
Construction
Design
Construction
Operational
Planning
Consideration
Construction: (Start-
up: 1/87)
Operational
Construction (Start-
up: 2/87)
Operational
Consideration
Operational
Operational
Operational
Operational
Operational
Operational
Construction (Retrofit-
1987 Start-up)
Pilot
Operational (Private
contractor)
Pilot
Type
Aerated Windrow
In-Vessel (Paygro)
A-SP
Aerated Windrow
Aerated Windrow
A-SP
In-Vessel
Aerated Windrow
A-SP (Pilot)
A-SP
A-SP
Aerated Windrow
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
In-Vessel or AS-P
Windrow
Aerated Windrow
A-SP (EKO Systems)
Windrow
Windrow
Windrow
Windrow
Windrow
Windrow
Aerated windrow
Sludge Volume
dry ton/day
(unless noted)
1.4
120-150
5
2
2-3
40
3.2
2.5
6
5 yds. /week
5
3.5
3
2,000/yr.
500 cu. yd./wk.
(§.20
6
(3300/yr.
12
18 cu. yd. /day
1.4/week
35 cu. yd. /day
120 cu. yd. /day
24 (if full
scale)
3-4/month
5+
?1.5
7-10
1.5-2
40
30 (At full
scale)
D-4
-------
APPENDIX D (Cont'd.)
FACILITIES COMPOSTING
MUNICIPAL SLUDGE IN THE U.S.
State
29. New Hampshire
30. New Jersey
31. New Mexico
32. New York
.
33. North Carolina
34. North Dakota
35. Ohio
Plant Name
1.
2.
3.
it.
5.
6.
7.
8.
9.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Claremont
Durham
Keene
Lebanon
Littleton
Merrimack WWTP
Herrimack: Lagoon
Milford
Plymouth
Buena Borough MUA
Burlington County
Camden County MUA
Cape May County MUA
Manville Boro STP
Middletown Township
Pennsvllle
Rockaway Valley MUA
Sussex County MUA
(Upper walkill)
Wanaque Valley MUA
Warren County MUA
(Pequest River)
Status
Operational (Start-
up: 11/86)
Operational
Operational
Operational
Pilot
Operational
Operational (Seasonal)
Construction (Start-
up: 12/86)
Operational
Operational
Design
Consideration
Operational
Operational
Operational
Operational
Consideration (Long-
term)
Operational
Consideration
Consideration
Type
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
A-SP
In-Veasel (Co-Composting)
In-Vessel
In-Vessel (Purac)
A-SP
A-SP
A-SP
In-Vessel
A-SP
In-Vessel
A-SP
Sludge Volume
dry Con/day
(unless noced)
6.4
.6
.8
1
21
15
2.5
.5
3.5
30
20-25
12
1.5
2.7
5.5
7
1
None
1.
2.
3.
4.
5.
6.
7.
8.
1.
2.
3.
4.
None
1.
Alden
Binghamton
Clinton County
(Plattsburgh)
Endicott
Guilderland
Herkimer County
Schenectady
Sylvan Beach
Charlotte
Hickory, Newton,
Conover & Catawba
Counties
Morganton (Catawba
River Plant)
Valdese
Akron
Operational
Design
Operational
Operational
Operational
Consideration
Construction
Operational
(Intermittent)
Design
Bid stage
Operational
Operational
Construction (Dry run:
A-SP
In-Vessel (Taulman-Weiss)
In-Vessel (Fairfield)
In-Vessel (Taulman-Weiss)
A-SP
In-Vessel (American
Bio-Tech)
A-SP
In-Vessel
In-Vessel
A-SP
A-SP
In-Vessel (Paygro)
15
25
2
20
24
1
60
36. Oklahoma
2. Columbus
3. Hamilton WWTP
4. Lake County
1. Tulsa
11/86)
Operational
Construction
Operational
Pilot
A-SP w/In-Vessel drying 24
(Paygro)
In-Vessel (Ashbrook-Simon- 17
Hartley)
Aerated windrow 7
A-SP
D-5
-------
APPENDIX D (Cont'd.)
FACILITIES COMPOSTING
MUNICIPAL SLUDGE IN THE U.S.
State
37. Oregon
38. Pennsylvania
39. Rhode Island
40. South Carolina
41. South Dakota
42. Tennessee
43. Texas
44. Utah
45. Vermont
46. Virginia
47. Washington
Plant Name
1.
2.
1.
2.
3.
4.
5.
6.
1.
2.
1.
2.
3.
4.
None
1.
2.
3.
1.
2.
3.
4.
1.
1.
1.
2.
3.
4.
5.
1.
2.
3.
Newberg
Portland
Hazleton Joint Sewer
Auth.
Lancaster
Lancaster
Philadelphia
Scranton
Springettsbury Township
Jamestown
West Warwick
East Richland County
PSD (Gills Creek)
Greenville
Hilton Head
Myrtle Beach
Bristol
Nashville: Central
Treatment Plant
Nashville: Dry Creek
Austin
El Paso: Haskell St.
Plant
El Paso: Socorro Plant
Fredricksburg
Salt Lake City: Central
Valley Plant
Bennington
Fairfax Cty. & City of
Alexandria
Hampton Roads San. Dlst.
Henrico County
Moores Creek
(Chariot tesville)
Upper Occoquan
Seattle
Seattle METRO
Miller Creek & Salmon
Status
Construction
Operational
Design
Construction
Operational (by A&M
Composting)
Operational
Operational
Operational
Operational
Operational
Operational
Consideration
Consideration
Operational
Bid stage
Operational
Operational
Pilot (6 yd. /every
few days)
Operational
Operational
Operational
Consideration
Design
Operational
Operational
Bid stage
Operational
Operational
Operational (by Groco,
Inc.)
Consideration
Consideration
Type
In-Vessel (Ashbrook-Slmon-
Hartley)
In-Vessel (Taulman-Weiss)
A-SP
In-Vessel (Taulman-Weiss)
A-SP
A-SP
A-SP
A-SP
Windrow
A-SP
In-Vessel (Taulman-Weiss)
In-Vessel
In-Vessel or A-SP
A-SP
In-Vessel
A-SP
A-SP
Windrow
Windrow
Windrow
Windrow
In-Vessel
In-Vessel
A-SP
A-SP
In-Vessel
A-SP
Aerated Windrow
A-SP
In-Vessel
In-Vessel
Sludge Volume
dry ton/day
(unless noted)
3.5 (at 15%
solids)
60
11.4
30
20-40 cu.
yd. /day
300
9.2
6
350 cu. yd./yr
3-5
4-5
35
393 tons of
compost/yr.
14.3
20 (1987: 40)
5-6
75-100
(Potential)
18
14
25-30
2
65
12
17.5
2.5
7.5
18
45
6-8
Creek (Southern King
Cty.)
48. West Virginia None
D-6
-------
APPENDIX D (Cont'd.)
FACILITIES COMPOSTING
MUNICIPAL SLUDGE IN THE U.S.
49.
50.
51.
State
Wisconsin
Wyoming
District of
Columbia
Plant Name
1. Portage
2. Stevens Point (Univ.
of Wisconsin)
None (interest expressej
1. Blue Plains
Status
Construction
Pilot
in starting a pilot research
Operational (In-Vessel
under consideration)
Type
In-Vessel (Co-Composting:
Ewe son)
A-SP (Co-Composting)
Sludge Volume
dry ton/day
(unless noted)
2.4
project)
A-SP
40
52. Puerto Rico
1. Arecibo
Design
A-SP
IS
Source: Biocycle, "Sewage Sludge Composting Maintains Momentum", November-December, 1986.
D-7
-------
APPENDIX E - SURVEY: FACILITIES INCINERATING
MUNICIPAL SLUDGE IN THE UNITED STATES
-------
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E-l
-------
APPENDIX F - SUMMARY AND CONCLUSIONS: INCINERATION
AND COMPOSTING TECHNOLOGY INVENTORY,
ECOLSCIENCES, INC., AUGUST, 1986
-------
APPENDIX F
SUMMARY AND CONCLUSIONS OF
INCINERATION AND COMPOSTING TECHNOLOGY
INVENTORY
ECOLSCIENCES, INC.
AUGUST, 1986
Based upon a review of the information compiled for the incineration
facilities, the following are important considerations in the implementation
of an incineration alternative:
o Incineration facilities have a longer operational history than
composting. Multiple hearth furnaces are most common, fluidized bed
furnaces are a more recent incineration technology, with few
operational facilities.
o Advantages of incineration include:
Flexibility and reliability.
Provides for on-site sludge management with reduced dependence
on haulers, weather conditions, application sites or decreasing
landfill capacity.
o In terms of cost, when selected incineration was often the most cost
effective alternative. These facilities are significantly effected
by rising fuel costs; however, depending upon the region, incinera-
tion may still be less costly than land intensive operations.
o System reliability is dependent on age and availability of backup
units. Of the facilities surveyed, operational time ranged from 7
days per week, 24 hours per day to 200 operation days per year.
o Operation problems noted include: induced draft fans, clinker
formation, low percent solids in sludge cake.
o Ash disposal is required; methods used by facilities surveyed
include on-site storage in lagoons and landfilling.
o Problems meeting particulate standards are common and may be related
to a variety of factors. Facilities surveyed corrected particulate
problems by adding wet scrubbers and changing sludge processing from
chemical to thermal conditioning.
A similar review of the information compiled for the composting
facilities, indicates the following to be important considerations when
implementing a composting alternative.
F-l
-------
Composting large volumes of sludge on a full scale basis has a
shorter operational history than incineration. This is particularly
evident for in-vessel processes which have been in operation for
only a few years in the U.S.
Advantages of the composting alternative include:
Provides for the beneficial reuse of sludge and the recovery of
a marketable product.
Cost effective.
Process reliability.
Flexibility in terms of processing and end product character-
istics.
The cost of constructing and operating a composting facility varies
widely and is dependent on process chosen and site specific
factors. All facilities surveyed indicated that composting was the
most cost effective sludge management alternative.
Composting method should be tailored to regional weather conditions
(i.e. seasonal variations, wet weather conditions), adjacent land
use (for aesthetics and odor reasons), and land costs (certain
methods require large areas for processing and storage).
Provisions to capture runoff, leachate and condensate are required.
Operation problems identified include: wet weather extends drying
time and causes much downtime in screening operations, fire hazard
in storage areas.
Odor problems are easily controlled by a number of methods, includ-
ing: increasing the bulking agent; fresh sludge ratio, changing
bulking agent, reduce frequency of turning piles, increase windrow
size, provide odor filler of screened compost or woodchips or vent
through scrubbers (such as wet or granular activated carbon) prior
to exhaust, chemical bath and misting methods, lime and masking
agents.
Routine temperature and oxygen monitoring is required {jhrough the
composting process; nutrients, metals and pH also sampled.
Compost product analyzed for nutrients, pH, metals, organics,
salmonella and other pathogens.
Compost products can be utilized for many purposes:: nurseries,
retail outlets, agricultural application, land reclamation, Highway
and Parks Departments, landfill cover, turf grass production,
hydroseeding, fertilizer carrier, soil amendment, ballfield
renovation, public. The facilities surveyed indicated that demand
for compost products generally outweighed production.
F-2
-------
Not all compost products are suitable for unrestricted public
distribution.
F-3
-------
APPENDIX G - SOLIDS MANAGEMENT ALTERNATIVES
COST ANALYSIS VALUES
-------
APPENDIX G
08/23/88
COST COMPONENT
TABLE 1
DEWATERING INCINERATION AND ASH LANDFILL ING
COST ANALYSIS VALUES
(MARCH 1988 DOLLARS)
ESTIMATED COSTS
ALTERNATIVE I ALTERNATIVE II
SIX UNITS FOUR UNITS
Capital Costs
Filter Press Building (1)
Site Work $1,697,000 $1,697,000
Building 10,400,000 10,400,000
Process Equipment 24,771,000 24,771,000
Subtotal $36,868,000 $36,868,000
Engineering & Contingencies 11,060,000 11,060,000
Subtotal $47,928,000 $47,928,000
Fluid Bed System (1)
Fluid Bed Reactor $10,794,000 $7,196,000 (2)
Afterburner 1,270,000 847,000 (2)
Air Preheater 3,238,000 2,159,000 (2)
Sludge Feed System 1,428,000 952,000 (2)
Scrubber 4,127,000 2,752,000 (2)
Dry Ash System 847,000 847,000
Wet Ash System 794,000 794,000
Fluidizing Blower 825,000 551,000 (2)
Induced Draft Fan 825,000 551,000(2)
Duct and Dampers 2,858,000 1,905,000 (2)
Uasteheat Boiler 2,064,000 2,064,000
Boiler Feedwater Pimps 286,000 286,000
Boiler Make-Up System 445,000 445,000
Condenser 365,000 365,000
Turbo-Generator 1,111,000 1,111,000
Electrical Suitchgear 211,000 211,000
Stacks 1,798,000 980,000 (3)
Process Piping 3,175,000 2,117,000 (2)
Instrumentation 3,810,000 2,540,000 (2)
Power Wiring 3,334,000 2,223,000 (2)
Sand Handling System 529,000 529,000
Building Modifications 4,762,000 4,762,000
Demolition Work 1,058,000 1,058,000
Subtotal $49,954,000 $37,245,000
Engineering & Contingencies 14,986,000 11,174,000
Subtotal $64,940,000 $48,419,000
1988 Estimated Project Cost $112,868,000
$96,347,000
(1) Based on Engineering Science concept design cost information
(2) Based on EPA four unit concept with values 4/6 of six unit concept costs
(3) Based on EPA four unit concept with value 1/2 of six unit concept
G-l
-------
APPENDIX G
08/23/88
COST COMPONENT
TABLE 1 (Continued)
DEWATERING INCINERATION AND ASH LANDFILLING
COST ANALYSIS VALUES
(MARCH 1988 DOLLARS)
ESTIMATED COSTS
ALTERNATIVE I ALTERNATIVE II
SIX UNITS FOUR UNITS
Operation And Maintenance Costs
Filter Press Dewatering (1)
Labor
Power
Chemicals and Supplies
Materials
Subtotal
Fluid Bed Incineration (1)
Labor
Power (3)
Ash Transport & Disposal
Makeup Sand
Maintenance Materials
Subtotal
Power Credit (1)
Subtotal
$1,206,000
541,000
2,333,000
42,000
$4,122,000
$1,206,000
541,000
2,333,000
42,000
$4,122,000
$865,000
686,000
3,056,000
55,000
1,484,000
$6.146,000
($808,000)
$5,338,000
$865,000
686,000
3,056,000
55,000
990,000 (2)
$5,652,000
($808.000)
$4,844,000
Total Annual O&M Cost
$9,460,000
$8,966,000
(1) Based on Engineering Science concept design cost information
(2) Based on EPA four unit concept with value 4/6 of six unit concept cost
(3) Based on Engineering Science Information Indicating 9X of Cost is for Startup
Fuel and 91X of Cost is for Electrical Power
G-2
-------
APPENDIX G
08/23/88
TABLE 2
DEWATERING, DRYING AND PRODUCT USE
COST ANALYSIS VALUES
(MARCH 1988 DOLLARS)
COST COMPONENT
ESTIMATED COSTS
Capital Costs (1)
Filter Press Building
Site Work $1,697,000
Building 10,400,000
Process Equipment 24,771,000
Subtotal $36,868,000
Engineering & Contingencies 11,060,000
Subtotal $47,928,000
Drying System (2)
Building and Site Work $3,742,000
Process Equipment 17,196,000
Subtotal $20,938,000
Engineering & Contingencies 6,281,000
Subtotal $27,219,000
1988 Estimated Project Cost $75,147,000
Operation And Maintenance Costs
Filter Press Dewatering (1)
Labor $1,206,000
Power 541,000
Chemicals and Supplies 2,333,000
Materials 42,000
Subtotal $4,122,000
Drying System (2)
Labor $741,000
Power 721,000
Fuel (3) 2,061,000
Maintenance (4) 705,000
Subtotal $4,228,000
Dried Product Revenue (5) ($1,067,000)
Subtotal $3,161,000
Total Annual O&M Cost
$7,283,000
(1) Based on Engineering Science concept design cost information
(2) BaMd on MEANS' and Manufacturer's info., 68,000 SO FT bldg., 6 units, 215 KU/DT, 580,000 BTU/DT, 6 Man/Shift
(3) Value includes energy credit of 240 mil. cu. ft. of available gas from Engineering Science reference
(4) Value based on 20X of labor, power, and fuel subtotal cost
(5) Based on 73,000 DTPY, 3.5X Nitrogen, $0.21/Lb N contract sale price and no cost for transport or marketing
G-3
-------
APPENDIX G
08/23/88
TABLE 3
DEUATERING IN-VESSEL COMPOSTING AND PRODUCT USE
COST ANALYSIS VALUES
(MARCH 1988 DOLLARS)
COST COMPONENT
ESTIMATED COSTS
Capital Costs (1)
Centrifuge Dewatering
Centrifuge Process
Equipment $13,454,000
Engineering & Contingencies 4,036,000
Subtotal $17,490,000
In-Vessel Composting System (2)
Site Work $6,825,000
Buildings & Covered
Storage Areas 64,722,000
Scrubber System 22,600,000
Process Equipment 33,249,000
Front End Loaders 835,000
Subtotal $128,231,000
Engineering I Contingencies 38,469,000
Subtotal $166,700,000
1988 Estimated Project Cost $184,190,000
Operation And Maintenance Costs (1)
Centrifuge Dewatering
Labor $1,206,000
Power 310,000
Chemicals 1,785,000
Materials 220,000
Sidestream Treatment 145,000
Subtotal $3,666,000
In-Vessel Composting System (2)
Labor $1,052,000
Bulking Agent 1,546,000
Power 1,637,000
Chemicals 1,383,000
Fuel and Lubricants 220,000
Maintenance 582,000
Supplies 139,000
Subtotal $6,559,000
Compost Product Revenue (3) ($392,000)
Subtotal $6,167,000
Total Annual DIM Cost $9,833,000
(1) Based on District Cost Data and Engineering Science concept design cost information
(2) Based on Engineering Science and Manufacturer's cost information
(3) Based on average producer contract sale price of $2.SO/TON; 4.3 cy compost/D.T. sludge;
50% solids in final product
G-4
-------
GANNETT FLEMING
APPENDIX G 08/23/88
TABLE 4
OCEAN DISPOSAL OF DEUATERED SLUDGE
COST ANALYSIS VALUES
(MARCH 1988 DOLLARS)
COST COMPONENTS ESTIMATED COSTS
Capital Costs
1988 Estimated Project
Costs None
Operation And Maintenance Costs
Annual Ott Costs
Vacuum Filter Dewatering (1)
Labor $1,810,000
Power 365,000
Chemicals and Supplies 2,535,000
Materials 57,000
Subtotal $4,767,000
Contract Ocean Disposal (2) $3,088,000
Administrative Costs (3) $309,000
Total $8,164,000
(1) Based on FY86 costs for dewatering supplied by District staff adjusted to 1/87 rounded dollars
(2) Based on available contract ocean disposal costs on east coast; $6.27/WT at 20X solids;
450 mile round trip; 73,000 DTPY sludge solids plus 25,500 DTPY conditioning chemicals
(3) Based on 10X of contract ocean disposal cost and complexity of contract operation
G-5
-------
APPENDIX G 08/23/88
TABLE 5
LAND APPLICATION OF DEUATERED SLUDGE
COST ANALYSIS VALUES
(MARCH 1988 DOLLARS)
COST COMPONENTS ESTIMATED COSTS
Capital Costs
Centrifuge Dewatering (1)
Centrifuge Process
Equipment $13,454,000
Engineering & Contingencies 4,036,000
1988 Estimated Project Cost $17,490.000
Operation And Maintenance Costs
Centrifuge Dewatering (1)
Labor $1,206,000
Power 310,000
Chemicals 1,785,000
Post-Liming Chemical 1,381,000
Materials 220,000
Side Stream Treatment 145,000
Subtotal $5,047,000
Contract Land Application (2) $12,988,000
Administrative Costs (3) $325,000
Total $18,360,000
(1) Based on District Cost Data and Engineering Science Concept Design Cost Information
(2) Based on District Contracts for Land Application; 73,000 DTPY Sludge Solids and Conditioning
Chemical, Dewatered to 21X Solids, 18,250 DTPY Post Lime, $35.50/WT
(3) Based on 2.5X of Contract Land Application Cost and Complexity of Contract Operation
G-6
-------
APPENDIX G 08/23/88
TABLE 6
LANDFILL ING OF DEUATERED SLUDGE
COST ANALYSIS VALUES
(MARCH 1988 DOLLARS)
COST COMPONENTS ESTIMATED COSTS
Capital Costs
Centrifuge Deuatering (1)
Centrifuge Process
Equipment $13,454,000
Engineering & Contingencies 4,036,000
1988 Estimated Project Cost $17,490,000
Operation And Maintenance Costs
Centrifuge Dewatering (1)
Labor $1,206,000
Power 310,000
Chemicals 1,785,000
Post-Liming Chemical 1,381,000
Materials 220,000
Side Stream Treatment 145,000
Subtotal $5,047,000
Contract Hauling (2) $9.513,000
Landfill Disposal Fee (3) $8,049,000
Administrative Costs (4) $238,000
Total $22,847,000
(1) Based on District Cost Data and Engineering Science Concept Design Cost Information
(2) Based on MEANS' and District Contract Hauling Prices; $26/VT; 50 Mile Round Trip,
73,000 DTPY of Sludge Solids and Conditioning Chemical, Deuatered to 21X Solids, 18,250 DTPY Post Lime
(3) Based on Landfill Disposal Fee of S22/UT at 21X Solids for 73,000 DTPY Plus 18,250 DTPY Post Lime
(4) Based on 2.5X of Contract Hauling Cost and Complexity of Contract Operation
G-7
-------
08/23/88
APPENDIX G
TABLE 7
DEUATERING INCINERATION AND ASH LAND FILL ING 100 DTPD
WITH LAND APPLICATION 100 DTPD AND PEAK LOADS
(MARCH 1988 DOLLARS)
COST COMPONENT ESTIMATED COSTS
Capital Costs
Filter Press Building (1)
Site Work $1,697,000
Building 10,400,000
Process Equipment 24,771,000
Subtotal 36,868,000
Engineering & Contingencies 11,060,000
Subtotal 47,928,000
Two Unit Incineration
Fluid Bed System (1)
Fluid Bed Reactor, 2 Units $3,562,000 (2)
Afterburner 419,000 (2)
Air Preheater 1,069,000 (2)
Sludge Feed System 471,000 (2)
Scrubber 1,362,000 (2)
Dry Ash System 424,000 (3)
Wet Ash System 396.000 (3)
Fluidizing Blower 272,000 (3)
Induced Draft Fan 272,000 (2)
Duct and Dampers 943,0000 (2)
Uasteheat Boiler 1,032,000 (3)
Boiler Feeduater Pumps 143,000 (3)
Boiler Make-Up System 222,000 (3)
Condenser 183,000 (3)
Turbo-Generator 555,000 (3)
Electrical Suitchgear 106,000 (3)
Stacks 900,000 (3)
Process Piping 1,048,000 (2)
Instrumentation 1,257,000 (2)
Power Wiring 1,100,000 (2)
Sand Handling System 264,000 (3)
Building Modifications 4,762,000
Demolition Work 1,058,000
Subtotal $21,820,000
Engineering fc Contingencies 6,546,000
Subtotal $28,366,000
Land Application None
1988 Estimated Project Costs $76,294,000
(1) Based on Engineering Science concept design cost information.
(2) Based on two unit concept with values 2/6 of six unit concept costs
(3) Based on two unit concept with values 1/2 of six unit concept costs
G-8
-------
APPENDIX G
08/23/88
TABLE 7 (Continued)
DEUATERING INCINERATION AND ASH LANDFILL ING 100 DTPD
WITH LAND APPLICATION 100 DTPD AND PEAK LOADS
(MARCH 1988 DOLLARS)
COST COMPONENT
ESTIMATED COSTS
Operation And Maintenance Costs
Fitter Press Dewatering (1)
Labor
Power
Chemicals and Supplies
Materials
Subtotal
Fluid Bed Incineration (1)(4)
Labor
Power
Ash Transport & Disposal
Makeup Sand
Maintenance Materials
Subtotal
Power Credit
Subtotal
Land Application
Contract Land Application
Administration Cost
Subtotal
Total Annual O&M Cost
$1,206,000
541,000
2,333,000
42,000
$4,122,000
$536,000 (5)
343,000 (6)
1,528,000
28,000
742,000 (3)
$3,177,000
($404,000)
$2,773,000
$4,373,000 (7)
109,000 (8)
$4,482,000
$11,377,000
(1) Based on Engineering Science concept design cost information
(2) Based on two unit concept with values 2/6 of six unit concept costs
(3) Based on two unit concept with values 1/2 of six unit concept costs
(4) Based on two unit concept loading of 100 DTPD which is 1/2 of the six unit concept cost
(5) Based on Engineering Science information with 1/2 the operating staff
of the 6 unit system and same maintenance staff level
(6) Based on Engineering Science information indicating 9X of cost
is for startup fuel and 91X of cost is for electrical power
(7) Based on District contracts for land application; 36,500 DTPY sludge solids
and conditioning chemical, dewatered to 32X solids, 9,125 DTPY post lime, $35.50/W.T.
(8) Based on 2.5X of contract land application cost and complexity of contract operation
G-9
-------
APPENDIX G
10/12/88
SUMPU
DISK#1
SALVAGE VALUE PLANT
STRUCTURES
TABLE 8
SOLIDS MANAGEMENT ALTERNATIVE
SALVAGE VALUE COSTS (1)
INCINERATION DEUATERING
ALTERNATIVE I ALTERNATIVE II DRYING AND
SIX UNITS FOUR UNITS PRODUCT USE
DEUATERING
IN-VESSEL COMPOSTING
AND PRODUCT USE
INCINERATION
TWO UNIT
WITH LAND
APPLICATION
Fitter Press Bldg.
Site Work
Building
$1,697,000
10,400,000
$1,697,000
10,400,000
$1,697,000
10,400,000
$1,697,000
10,400,000
Solids Processing
Building
Stacks
Building Modifications
Drying BuiIding &
Site Work
$1,798,000
4,762,000
$900,000
4,762,000
3,742,000
$900,000
4,762,000
Compost Buildings
Site Work
BuiIdings &
Covered Areas
6,825,000
64,722,000
Total Plant
Structures
$18,657,000 $17,759,000 $15,839,000
$71,547,000
$17,759,000
(1) Based on values in Tables 1, 2, 3 and 7 of Appendix G and existing facilities
were considered sunk cost in accordance with EPA guidelines. The salvege value is the
value based on a straight-line depreciation from the initial new facility cost
at the time of analysis to the end of the planning period. Process equipment
given a design life of 20 years has no salvage value.
G-10
-------
APPENDIX H - DESIGN YEAR SLUDGE QUANTITIES
SUBJECT TO EIS
(Graph of Annual Average, Peak, and Non-Peak
Month Sludge Quantities)
-------
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APPENDIX H
-------
APPENDIX I - ADDITIONAL CONSIDERATIONS
REGARDING LAND APPLICATION OF
SEWAGE SLUDGE IN VIRGINIA AND MARYLAND
-------
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION III
PHILADELPHIA, PENNSYLVANIA
ADDITIONAL CONSIDERATIONS
REGARDING LAND APPLICATION
OF SEWAGE SLUDGE
IN VIRGINIA AND MARYLAND
A SUPPLEMENT TO THE
BLUE PLAINS SLUDGE MANAGEMENT EIS
MARCH 1989
PREPARED BY:
GANNETT FLEMING ENVIRONMENTAL ENGINEERS, INC.
HARRISBURG, PENNSYLVANIA
-------
ADDITIONAL CONSIDERATIONS
REGARDING LAND APPLICATION
OF SEWAGE SLUDGE
IN VIRGINIA AND MARYLAND
A SUPPLEMENT TO THE
BLUE PLAINS SLUDGE MANAGEMENT EIS
TABLE OF CONTENTS
Page
A. HISTORIC BLUE PLAINS SLUDGE DISPOSAL PRACTICES
1. Historic Practices 1-1
2. Summary 1-3
B. LAND AVAILABILITY FOR LAND APPLICATION OF SEWAGE SLUDGES
1. Currently Permitted Acreage 1-3
2. Acreage Required 1-4
3. Trends in Land Availability 1-8
4. Land Application and Agricultural Activities 1-8
5. Summary 1-9
C. THE PERMITTING PROCESSES FOR SEWAGE SLUDGE LAND APPLICATION SYSTEMS
1. Virginia Permitting Process 1-10
2. Maryland Permitting Process 1-12
3. Permit Approval Success Rates 1-15
4. Local and National Policies and Trends 1-15
5. Summary 1-18
D. ENVIRONMENTAL CONCERNS
1. Contamination of Water Sources 1-18
2. Food Chain Toxicity 1-20
3. Gaseous Emissions 1-22
E. ENERGY CONSUMPTION
1. Energy Consumption 1-26
2. Summary 1-28
F. LAND PURCHASE/LEASING
1. Land Purchase/Leasing 1-28
2. Summary 1-29
G. LORTON LANDFILL CAPACITY 1-29
SOURCES 1-32
-------
LIST OF TABLES
Page
1. Permitted Acreage for Land Application 1-5
of Sewage Sludge
2. Comparison of Emissions from Land Application 1-23
vs. Incineration
3. Summary of Energy Cost 1-27
4. Summary of Land Costs for Sludge Land 1-30
Application Sites
LIST OF FIGURES
1. Permitted Land Application Acreage and Total Cropland 1-6
Acreage
2. Virginia and Maryland Land Application Permitting 1-13
Processes
-------
A. HISTORIC BLUE PLAINS SLUDGE DISPOSAL PRACTICES
1. Historic Practices
A critical period for sludge management at Blue Plains was from 1974 to
1984 when a number of events occurred that have influenced the District's
outlook on sludge management. This was the period known locally as the
"sludge war" which was finally settled by the negotiation of the 1974 Sludge
Memorandum of Understanding and the 1985 Intermunicipal Agreement. In
chronological sequence, these are the major events that occurred during that
time frame:
o 1974 - The Blue Plains STP Agreement between the District and the
users of the plant established the principle that the users of the
plant would accept their proportion of the sludge for disposal.
o 1975 - The EIS reached the conclusion that incinerators were unac-
ceptable due to the potential for air pollution and fuel costs.
o 1976 - Maryland continued to accept 150 DTPD for land disposal, but
public and official opposition was building. Composting at
Beltsville began operations using Blue Plains sludge. The 1974
agreement was extended to 1978 and composting was considered for the
site near Blue Plains known as Oxon Cove. This alternative was
opposed by local citizens and abandoned. Some trenching continued
in Maryland.
o 1978 - A solids building that could accommodate incinerators was
constructed at Blue Plains.
o 1979 - A Court Order was issued requiring the District to compost
on-site and Montgomery County to accept its share, which led to the
development of Site-II.
o 1980 - Composting at Western Branch and Dickerson, Maryland began.
Maryland stopped permitting trenching sites for dewatered sludge
disposal.
1-1
-------
o 1981 - In an amendment to the 1974 agreement among users and the
District government, it was agreed to have a centralized sludge
handling facility in place and operational by 1987.
o 1982 - 1984 - Interim composting sites at Western Branch and
Dickerson shut down. The District contracted with Dano and other
companies to alleviate the sludge problem.
o 1984 - WSSC contracted with haulers to dispose of the residues. The
District had hoped that these materials would be marketable, but
none were and the materials remained at the site until the current
haulers removed it. At the same time, the District contracted for
the interim land application of sludge at about the same time as EPA
published its sludge recycling policy.
o 1984 to present - Blue Plains sludge is being land applied at the
rate of 140 DTPD.
The design rate of sludge production used for the EIS is 410.5 DTPD. It
is assumed that the earliest date this level will be reached is 1997. An
average (and probably more realistic) sludge production rate of 410.5
DTPD rate will probably not be reached until well into the 20th century,
at 2010. In any event, the EIS was only to consider 200 DTPD, the amount
the District has proposed for incineration.
In effect, a phased approach to land application is already in place.
Currently, 37.5 DTPD is being composted at Site-II and an increase to
87.5 DTPD has been FONSI'd. A FONSI also applies to the nearly 123 DTPD
that is to be composted at Blue Plains. For its part, the District has
considered composting up to nearly 150 DTPD. Land application currently
accounts for roughly 140 DTPD.
o Site-II will phase up from 37.5 DT/dy to 87.5 DTPD:
o On-site will phase up from the current 70 DT/dy to 123 DTPD; and
o Land application would involve a phase up from the current 140 DTPD
to 210.5 DTPD.
1-2
-------
2. Summary
Sludge management at Blue Plains has had a long and complicated
history. Sludge is currently being composted at Site II and at Blue Plains.
The remainder is being land applied, a practice that is recommended in the
draft EIS for continuation.
B. LAND AVAILABILITY FOR LAND APPLICATION OF SEWAGE SLUDGE
1. Currently Permitted Acreage
Table 2.5 in the Draft EIS contains a summary of the permitted
acreage for land application of sludge in each of 20 counties in Maryland and
Virginia. This information was supplied by the three land application con-
tractors operating at Blue Plains and verified by the appropriate state
agencies. At the time when this data was collected, there were 69,874 acres
permitted for land application. This acreage is not solely permitted for Blue
Plains sludge and includes acreage which could be used for sludges from other
treatment plants. Based upon information from BioGro Systems, acreage permit-
ted only to receive Blue Plains sludges are in Louisa County, Virginia (3,759
current permitted acres).
This data has been updated as part of this report and is presented
in Table 1 and illustrated in Figure 1. The three contractors have provided
permitted acreage numbers as of January 1989. Culpeper County, Virginia no
longer has permitted acreage. Calvert, Charles and St. Mary's County,
Maryland and Orange and Prince William County, Virginia have been added to the
list. The total permitted acreage has increased to 78,280. This is an
increase of 8,406 acres since the last inventory. In addition to the 78,280
acres currently permitted, there are 27,543 additional acres pending permit
approval. Approval of these applications would bring the total permitted
acreage to over 105,800 acres.
1-3
-------
2. Acreage Required
The draft EIS states (Pg. 2-21) that the disposal of 200 DTPD over
the next 20 years would require an estimated 37,700 permitted acres based on
the assumed conditions. Changing the application cycle from 3 years to 5
years at the Virginia sites to provide increasingly conservative estimates
while maintaining the other conditions results in increasing the acreage
requirement to about 59,400 acres. Based on information supplied from state
regulatory agencies and contractors it is apparent that about 78,280 acres of
permitted land are available for the application of sewage sludge. The 78,280
acres represent 5.1 percent of the total agricultural acreage in the counties
in which permitted acreage exists, according to information obtained from the
"1982 Census of Agriculture" for Maryland and Virginia.
Calculations
Given: Corn Crop: 180 Ibs N/ac required
Sludge: 70 Ibs N/ton and 40% available
EPA Site Availability Factor: 1.4
Permitted Acres: 27,215 Ac Maryland
51,065 Ac Virginia
Sludge Production: 73,000 DTPY
Loading Rate
Tons/ac - 180 Ibs N/ac/ (70 Ibs N/ton) (0.40)
- 6.4 tons sludge/ac
Land Application Potential Based on Permitted Sites
Maryland Tons/yr. - 27,215 Ac (1/1.4) 6.4 ton/Ac
- 124,411 tons/yr.
Virginia Tons/yr.3 - 51,065 Ac (1/1.4) (1/3) 6.4 ton/Ac
- 77,813 tons/yr.
Tons/yr.5 - 51,065 Ac (1/1.4) (1/5) 6.4 ton/Ac
- 46,688 tons/yr.
1-4
-------
Table 1
Permitted Acreage
for Land Application of Sewage Sludge
County
Maryland
Calvert
Caroline
Carroll
Charles
Frederick
Howard
Kent
Prince George's
Queen Anne's
St. Marys
Talbot
Subtotal
Virginia
Caroline
Essex
Fauqui er
Goochland
Hanover
King George
King and Queen
King William
Loudoun
Louisa
Orange
Prince William
Subtotal
Total
Total1
Cropland
26,918
107,719
136,433
43,372
187,201
40,349
N/A
39,231
134,909
50,729
97,951
864,812
42,617
51,173
135,736
27,991
69,300
21,502
34,256
40,641
135,040
40,950
60,528
N/A
659,734
1,524,546
Total
Permitted
Acreage
Enviro-Gro
0
1.0002
350
0
200
2.500
500
1,100
1,0002
0
0
6,650
0
0
0
2,000
2,000
1,200
0
0
0
0
0
1,000
6,200
12,850
Total
Permitted
Acreage
Bio-Gro
500
1,734
260
670
0
416
0
7,977
3.056
104
3,982
18,699
2,875
9,575
5,301
1,297
4,699
1,608
4,562
4,649
4,596
3,759
1,944
0
44,865
63,564
Total
Permi tted
Acreage
Ad + Soil
0
0
0
0
0
0
0
0
1,866
0
0
1,866
0
0
0
0
0
0
0
0
0
0
0
0
0
1,866
Total
Permitted
Acreage
500
2,734
610
670
200
2,916
500
9,077
5,922
104
3,982
27,215
2,875
9,575
5,301
3,297
6,699
2,808
4,562
4,649
4,596
3,759
1,944
1,000
51,065
78,280
Acreage
Pending
Approve I
0
32
0
1,225
0
305
0
1,303
2,317
0
0
5,182
8.915
555
783
2,531
295
2,567
3,843
1,534
1.348
0
0
0
22,361
27,543
1. Data prepared by BioGro based upon the "1982 Census of Agriculture" for Maryland and
Virginia.
2. The actual acreage values for these two counties is unknown, but was estimated by
Enviro-Gro as 2000 to 5000 acres for both. A conservative estimate of 1000 acres for
each county is given here.
Sources: 1, 2, 3.
1-5
-------
FIGURE 1
1-6
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Potential Range - 171,099 to 202,224 tons of sludge/year could be applied
as compared to 73,000 DTPY of sludge produced, based on given conditions.
Land Application Required Acreage
Maryland Tons/yr. - 73,000 DTPY (0.32)
- 23,360 DTPY
Acres - (23,360 DTPY / 6.4 tons/Ac) 1.4
- 5,110 acres
Virginia Tons/yr. - 73,000 DTPY (0.68)
- 49,640 DTPY
Acress - (49,640 DTPY / 6.4 tons/Ac) 1.4
(3 yr. cycle)
- 32,576 acres
Acres5 - (49,640 DTPY / 6.4 tons/Ac) 1.4
(5 yr. cycle)
= 54,294 acres
Required Range 37,686 to 59,404 acres/year depending on the
application cycle used at Virginia sites. This requirement is lower
than the 78,280 acres currently permitted.
A second scenario involves the approach where reclamation applica-
tion rates are used. Under this approach, assuming the production of 1,800
wet tons per day, and the application rate of 60 tons per acre, this program
would require 30 acres per day and a total of about 11,000 acres per year.
However, the regulations allow a program of reuse of the acreage over a period
of several years with a following period of "rest" prior to intensive farming
or development.
Several other alternative analyses are also possible resulting in
the reduction of total acreage needed. Therefore, even by using the most con-
servative approach, permitted land for sludge application is available well in
excess of the acreages actually required.
1-7
-------
3. Trends in Land Availability
The permitted acreage for land application of sludge in the D.C.
area has been gradually increasing since land application was initiated for
Blue Plains sludge in 1984. The amount has increased 8,406 acres since the
last inventory in 1988. An additional 27,543 acres is pending permit
application approval. While this area is not reserved, strictly for sludge
from Blue Plains, it represents only 5.1 percent of the total agricultural
acreage in the two state area. In addition, since sludge application was
begun in 1984, the hauling distance has been reduced by roughly 25%; from a
one way average of 87 miles to 67 miles.
The haulers do not enter into long-term contracts with farmers
because: a) the demand is so great that farmers make their needs known
sufficiently in advance for planning; and b) contracts require commitment on
the part of the hauler to provide a certain quantity of plant nutrients. They
are reluctant to make such guarantees because of demands and business
considerations.
4. Land Application of Agricultural Activities
Figure 1 in this section shows the number of acres permitted for
land application of Blue Plains sludges in Maryland and Virginia. This
information is based upon data provided by three land application contractors
including: Enviro-Gro, Bio-Gro and Ad+Soil. Figure 1 also shows the acreage
of farmland in Virginia and Maryland that is potentially available for land
application.
The area in Virginia stretching from the Norfolk/Newport News area
to Richmond and north to Washington, D.C. will see heavy development along the
rivers, bay and ocean front over the next 10-20 years. However, the inland
areas are projected to remain largely in agricultural uses and therefore
provide the available land for future land application needs.
1-8
-------
The picture in Maryland is virtually identical to Virginia, with the
Eastern Shore and southern Maryland farming areas remaining fairly stable for
the next 20 years. Only 5% of these agricultural lands are currently under
permit to accept sludge, however, the acreage under permit does not mean that
every permitted area is receiving sludge. At the current application rates,
only about half of the acreage is being used.
In Virginia, sludge from Blue Plains represents about 75% of the
total that is applied to lands. The competition for sludge is actually keener
among the farmers than among the generators since the only major centers of
sludge production are Richmond, the Atlantic Plant (serving the Norfolk,
Newport News, Virginia Beach area), and Roanoke.
In Maryland, about 40,000 DTPY of sewage sludge from Blue Plains are
land applied to agricultural lands. This represents nearly 90% of that
state's land application program. Heavy competition may soon come from
Baltimore's 60,000 DTPY that is planned for land application. Most of the
time, the sludge is of sufficient quality, meaning that it can be used for
application on agricultural lands. Currently, an abundance of lands is
available so that Baltimore's program is no threat to the land available to
Blue Plains. Other sources of sludge are Carroll County, MD (650 DTPY),
Charles County, MD (2,000 DTPY), and Howard County, MD (2,500 DTPY).
5. Summary
The trend over the past five years has been toward increasing
availability of land permitted for land application of sludge. The current
amount of 78,280 acres of permitted land has an estimated capacity for 171,099
to 202,224 DTPY; well in excess of the 73,000 DTPY proposed for land applica-
tion from Blue Plains. The amount of land required for Blue Plains is
estimated at 37,700 to 59,400 acres. This represents 48.2% to 75.9% of the
current permitted acreage. Only 5.1 percent of the existing agricultural
acreage in the counties inventoried has been permitted for land application.
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C. THE PERMITTING PROCESSES FOR SEWAGE SLUDGE LAND APPLICATION SYSTEMS
1. Virginia Permitting Process
This section of the report is based upon the "Draft Revisions to the
Sewerage Regulations Pursuant to Section 62.1-44.19(8) of the Code of Virginia
(1950), as amended" dated April 1, 1988. Although these regulations are
subject to further revision before they are adopted, discussion with the
Virginia Department of Health^ revealed that little, if any, changes to the
permitting process are expected. Variations from the existing permitting
process are noted when applicable.
Under the proposed regulations, the owner (sludge generator) will
apply for a Virginia Pollution Abatement (VPA) permit through submission of a
sludge management plan in compliance with applicable sections of Part 3,
Article 7 and Appendix G. If the plan includes the construction of sludge
storage or processing facilities, the owner must submit final engineering
documents, in accordance with Section 1.6 concurrently with the submission of
the plan. The owner submits copies of these documents to the appropriate
regional office of the State Department of Health and copies to the appropri-
ate regional office of the State Water Control Board. If the owner contracts
out the sludge application program, the owner must be permitted, but may have
the contractor included as a co-permittee. The owner should notify landowners
adjacent to proposed application site(s).
In the existing system the contractor holds the permit. Part of the
justification for the change involves giving the owner the responsibility for
the land application program. The Commonwealth makes no bonding or other
assurance requirements in the draft regulations as this is to be left up to
the owner's discretion.
The Department and the Board will review the plan and engineering
documents (if applicable) to determine if they are complete. The Department
notifies appropriate local governments in accordance with current statutes and
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procedures. The Department may schedule a public meeting in accordance with
these statutes. The Board develops a draft certificate and forwards a
complete copy to the owner.
The owner then authorizes the Board to advertise the permit
application in the form of a public notice by publication for two successive
weeks, one week apart, in a newspaper of general circulation in the county,
city, or town in which the land application or storage site(s) are located.
The public comment period extends 30 days from the first day after the
publication of the notice. The Board will evaluate the comments received as a
result of the public notice and determine whether a public hearing is
necessary. If so, the Board will prepare a public notice of the hearing and
hold the hearing after completion of the public notice period. The Board will
then issue, reissue, modify or deny the certificate.
If the determination proposed is to deny the certificate, the Board
must so advise the owner along with the requirements, if any, necessary to
modify that determination.
Upon issuance (reissuance or modification) of the certificate, the
owner may initiate operation of the plan and may begin construction of the
storage facilities. Prior to operation of the storage facilities, the owner
must submit an O&M manual in accordance with Section 1.8.
According to a 1986 article entitled "Winning Strategies for Land
Application" published in BioCycle magazine and written by Mr. John Walker of
the U.S. EPA, the Virginia sludge permitting process frequently requires six
months or longer. This statement was verified by the Virginia Health Depart-
ment. The permit is then valid for 5 years, if limitations are met. The
permit renewal process is very similar to the original process, with the
exception that public hearings may not be required. Therefore, the renewal
process is sometimes shorter than six months.
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Under the current system the contractors obtain a permit for a site
and add other sites through amendments to the permit. The only change in the
revised regulations is the owner will be the holder of the permit. Separate
permits for all sites used by the owner will not be reqviired.
A flow diagram on the next page illustrates the permitting processes
of Virginia.
2. Maryland Permitting Process
Basic differences between the Virginia and Maryland permitting
process include bonding requirements; contractor, rather than owner permit-
ting; and a shorter permit approval and renewal process in Maryland.
Sewage sludge utilizers must file a bond or other approved security
with the Maryland Department of the Environment that will be conditioned upon
the fulfillment of any requirement related to the sewage sludge utilization
permit. The amount of the bond for land application permits is $25,000 for
agricultural loading rates and $50,000 for marginal land loading rates.
Although each site is permitted separately in Maryland, applicants for
agricultural or marginal land application sites may file one bond for several
sites equivalent to the costs listed above for the first site and 40 percent
of that bond amount for each additional site, up to a maximum total bond of
$200,000.
There are specific procedures for any complete application to either
land apply sewage sludge on marginal land or before construction can begin on
any permanent facility designed primarily for sewage sludge utilization. The
Department shall publish notice in a local newspaper having a substantial
circulation in the affected county and mail a copy of the notice and the
application to the local health official, the chairman of the county
legislative body, and the elected executive, if any, of the respective county
or municipality in which these activities would occur. Within 15 days of the
receipt of the complete application, the executive or legislative body of the
county or municipality may request a public hearing. If requested, the
Department will make all arrangements and publish a notice in a newspaper of
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general circulation in the affected area 7 days in advance of the hearing and
will then hold the hearing. Any comments received must then be taken into
account in the permit approval or denial process.
For permit applications for land application of sewage sludge to
other than marginal land, the Department still mails notices to appropriate
local officials. Those officials then have 10 days to request a public
informational meeting. The Department must then publish notice of the meeting
5 days prior to the meeting and hold the meeting. Comments received should be
reviewed in the permit approval or denial process.
For either type of application, the local governments have 20 days
after notification to provide the Department with written comments and sugges-
tions regarding issuance, denial or restrictions for the permit. Notification
is also given to counties within one mile of a proposed application site if
one exists other than the county in which the site is located.
The Department may consolidate the hearings or informational meet-
ings for more than one permit application if several exist in one general
area.
Permit applications cannot be denied strictly because of public
opposition. Denial must be based upon undue risk of environmental hazards;
inability to meet application or regulatory requirements; the applicant's
inability to fulfill permit requirements for other sites; or a lack of
sufficient resources on the part of the applicant to meet the provisions of
the permit. The permit approval process, upon receipt of a complete
application, typically takes between 45 and 90 days, unless significant
modifications need to be made.
Sewage sludge land application permits may not exceed 5 years.
Renewals may be granted if the proper renewal application form is completed,
appropriate fees are paid and permit requirements have been met and can
continue to be met. The renewal process is typically faster than the initial
permitting process.
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The Department will consider all applications to change cover crops,
adjust application rates for different cover crops or current sludge analyses,
to add other sludges from the same source treated by PSRP or PFRP, change haul
routes, change application methods or change transportation vehicles to be
minor permit modifications and these changes can be made without going through
the permit approval process again. Other modifications may necessitate a
repeat of the approval process.
3. Permit Approval Success Rates
According to the Virginia Department of Health^, the success rate
for land application permits is approximately 95 percent. Some sites have
been turned down due to elevated water tables, soil limiting zones, or other
similar restrictions. The Department or Board cannot deny a permit applica-
tion based upon public opposition. Some applicants have been requested to
withdraw their application because of anticipated public opposition, but no
permits have been denied because of it.
The success rate for permit applications in Maryland^ is similar to
the Virginia rate. Permits are often modified from the initial application to
account for soil or sludge limiting factors, but the application is rarely
denied in total.
4. Local and National Policies and Trends
Virginia has a "pro-sludge" land application policy^ and the
Commonwealth sees sludge application on agricultural and disturbed lands as a
beneficial use of a resource.
The existing and draft regulations contain several waivers of
requirements where application rates of less than once in five years are
proposed. These waivers are included because of the excess available land
around the state for land application, not from a fear of environmental
degradation resulting from more frequent loadings. Mos-t sites do have resting
periods between applications but sites with annual loadings do exist.
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Maryland also has a policy supporting the reuse of resources^.
While the state's regulations are expected to be tightened over time to ensure
proper land application practices, their policy prefers composting and land
application of sewage sludge over other disposal practices.
Information provided by both state contacts and contractors is in
close agreement.
o A permit for land application has rarely been denied because
farmers who want the material have thorough soil and parent
material analyses included with the permit application.
Therefore, permit approval is a virtual certainty in all cases.
o Permits encountering public opposition are few in number
because the state agencies discourage applications from those
areas where opposition is anticipated. In questionable areas,
the state agency carries out pre-permit surveys to ascertain
the potential for opposition, does pre-project coordination,
and may hold public meetings and hearings prior to permitting.
o On two occasions, sites were lost to a sludge hauler due to
development. Both sites were selected for proximity to the
sludge source and were not sufficiently investigated prior to
permit application for development pressures. These
experiences were early in the history of the contractor's
sludge application business in Pennsylvania.
o No sites have been revoked for these reasons in the District's
program, but none of the contractors are concerned because the
demand is so great that loss of sites would be quickly recti-
fied. In fact, one contractor has already begun the process of
permitting lands farther from the District in anticipation of
development pressures and to accommodate other municipalities'
needs.
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o One contractor has been cited for 12 - 15 violations over the
15 years or more of his business. Violations were for odors
and corrections were immediately made without loss of permit.
o EPA's John Walker relates that the permitting process is
evolving nationally and the possibility exists that regulations
too restrictive to allow for land application of some sludges
will result. However, it appears that the District's material
is of sufficiently high quality to preclude any permit denials
in the foreseeable future.
o Permit criteria are based upon USDA and EPA regulations that
are backed up by state land grant college research.
In addition to these state policies and trends, John Walker explains
the historical perspective for the period since 1976, as follows:
o From 1976 through 1980, recycling of sludge rose to nearly 40%
of the total sludge generated.
o By 1988, this figure was up to 50%, with more than half of the
nation's wastewater treatment plants operating some variety of
recycling process.
o Baltimore has incorporated pretreatment and now recycles most
of its materials.
o In Maryland, approximately 80% of the sludge is recycled.
o Land application and composting are used in disposing of 50% of
the sludge produced in Virginia.
o Site II, in Calverton, Md. (where 40 DTPD of Blue Plains sludge
is composted) won this year's sludge recycling award for their
efforts at controlling odors.
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o The current attitude in Maryland is that proper land applica-
tion practices are a statewide concern and efforts towards
increased state control are underway. However, Maryland^ views
land application of properly treated sewage sludges in
appropriate areas as a beneficial reuse of a resource and the
state prefers the recycling of resources over product disposal.
5. Summary
The permitting process in Virginia is a lengthy (6 months or longer)
and thorough process that provides necessary safeguards and public input into
the process. Under the current system, the contractors obtain and hold the
permits. With proposed draft regulations the owner (sludge generator) will
apply for and obtain the permit. Permits are valid for 5 years.
Procedures in Maryland are similar except that bonding is required
by the applicant; the contractor holds the permit; and the approval process
can take less time for approval. Permits are valid for 5 years.
Most land application permits are approved. According to both
states approximately 95 percent of the land application permits are approved.
Both states support a policy of beneficial reuse of a resource.
This is reflected in state-wide regulations that are stringent yet provide a
process that provides for permitting of sites throughout both states.
D. Environmental Concerns
1. Contamination of Water Sources
Regarding land application, studies by Clemson University, the
University of Iowa, and the Virginia Polytechnic Institute show that ground-
water pollution is more severe with chemical based fertilizers than with
organic based soil amendment due to the greater solubility of the chemical
salts commonly used in chemical based amendments. The Clemson study is
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briefly summarized and referenced in the EIS on page 4-35. Both application
rates and tillage are being further studied by Virginia Polytechnic Institute
and State University and Pennsylvania State University.
The EIS (Page 4-35) presents the concept of reduced nitrogen runoff
from fields receiving sludge to meet crop fertilizer needs as compared to com-
mercial fertilizer. As stated in the EIS, "This form of pollution is highly
variable because it depends on precipitation and local conditions."
Calculations of a quantity appears to be difficult at this time
because of a range of varying reported results. However, an illustrative
value can be determined if one applies the values for ammonium nitrogen, NH4-N
from Table 4 of the Clemson paper cited earlier and EIS Table 4-12:
Calculation
Given: Blue Plains Sludge Nfy-N 1.04 Ibs/ton
Fertilizer NIfy-N loss in runoff 7.1%
Sludge NH4-N loss in runoff 2.1%
Application rate 73,000 DTPY
Fertilizer NH4-N - Sludge NH4-N
Sludge NH4-N - 73,000 DTPY (1.04 Ibs/ton)
= 75,920 Ibs NH4-N
Fertilizer NH4-N runoff - 75,920 Ibs Nfy-N (0.071)
- 5,390 Ibs NH4-N/yr.
Sludge NH4-N runoff - 75,920 Ibs Nfy-N (0.021)
- 1,594 Ibs NH4-N/yr.
Estimated ammonium nitrogen reduction due to sludge replacement of
fertilizer is about 3,780 Ibs/yr. based on the above conditions.
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Ground and surface water contamination from sludge land application
sites is'estimated to be less than the amount originating from the same site
using commercial fertilizer. Both Maryland and Virginia have groundwater
monitoring requirements, loading rate limits, and sludge constituent and
treatment requirements as safeguards to limit potential water contamination.
Development of a nitrogen removal offsetting credit for the Blue
Plains Wastewater Treatment Facility if land application of sludge nitrogen is
used in place of commercial nitrogen fertilizer is difficult to calculate and
presents a complex regulatory policy issue.
Summary
Existing research shows that nutrient runoff from sludge amended
sites is less than the amount from the same sites using commercial fertilizer.
Maryland and Virginia have strict regulatory requirements to limit the
potential of environmental impacts on ground and surface waters. Development
of a nitrogen removal credit for land application used in place of commercial
nitrogen fertilizer is difficult to calculate and presents a complex regula-
tory policy issue.
2. Food Chain Toxicity
In order to determine the potential threat of food chain toxicity
resulting from a Blue Plains sewage sludge land application program, a series
of "Environmental Profiles and Hazard Indices for Constituents of Municipal
Sludge" printed by US EPA were consulted. Specifically, the hazard indices
for cadmium, chromium, copper, lead, nickel and zinc were evaluated to
determine the potential food chain toxicity hazards arising from land applying
Blue Plains sludge at agricultural and marginal land rates.
Cadmium, lead and zinc were the only metals for which food chain
toxicity hazard indices were exceeded for sludge loading rates below 100 tons
per acre per day. Although no loading rate maximums for marginal lands were
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given in the Maryland or Virginia regulations, the 100 ton level was estab-
lished here as a conservative estimate of the maximum permittable loading
rate.
Cadmium
The background level of cadmium in the soil used in the EPA testing
(0.2 ppm) was high enough to cause decreased egg production in chickens fed a
diet of earthworms from the site. Chickens were used as the indicator species
because of their high level of sensitivity to cadmium. Background levels on
sites used for Blue Plains sludge may be higher or lower than the background
level in the study. The addition of 22 tons per acre of sludge to the test
site increased the risk of this hazard by 2.5 times. The amount of the
increased risk from applying dewatered raw Blue Plains sludge would be less
because the average cadmium level in Blue Plains sludge is 80 percent of the
sludge used in the EPA study. In addition, the chance of this impact actually
taking place is decreased further by the common use of commercial feeds in
chicken farming.
The cadmium level in soil loaded with 22 tons per acre of sludge was
also high enough to exceed the recommended daily cadmium intake of human
vegetarians fed a diet of crops grown on the site. Crops grown for direct
human consumption cannot be grown in sludge amended soils in Virginia for a
period of m to 3 years. The limitation in Maryland is for three yeras. In
addition, the plant tissue level at which the hazard-index is first exceeded
(8.9 ppm) is equivalent to the maximum cumulative loading of cadmium in
Maryland in Virginia. Therefore, even if the crops withdraw all of the soil's
cadmium in the application year, the likelihood of a significant health hazard
is low. The three year waiting period is an additional safeguard to mitigate
the potential hazard.
The only hazard index exceeded for lead involved exceeding the
acceptable daily intake of 150 ug for toddlers ingesting crops grown on sludge
amended soils; animal products from animals ingesting crops grown on sludge
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amended soil; and the sludge amended soil itself from sites loaded at rates of
22 tons per acre or more. The existing regulatory safeguards limiting crop
production and human access to land application sites are adequate to reduce
the risk of this hazard.
Zinc
The background level in the soil used in the EPA studies (44 ppm)
was sufficient to cause a decrease in growth, hemoglobin and hematocrit in
Japanese quail. However, this species is not typically found in this region
of the United States. No hazard indices were exceeded for chickens or
turkeys, which were the two other species evaluated in the EPA study.
Summary
The most significant risk of food chain toxicity resulting from
metals typically found in a sewage sludge land application program is from
cadmium. Virginia and Maryland have maximum annual and cumulative loading
rates that appear to be sufficient to at least significantly reduce, if not
eliminate altogether, the potential of any impact. Use of commercial chicken
feed or otherwise restricting the interaction of chickens and products from
sites with high cadmium levels will further reduce the potential for any
impact.
3. Gaseous Emissions
A Dialog Science literature search for titles describing gaseous
emissions from sewage sludge was conducted to determine the extent of the
research involving gaseous emissions associated with the land application of
sewage sludge. There are odors associated with non-volatile gas emissions
from treated sludge. These gases include, among others, sulfur dioxide (S02),
ammonia (NH3), and methane. Although these gases give off an unpleasant odor,
they are not harmful in the concentrations typically present and the odor is
alleviated once the treated sludge is incorporated into- the soil.
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There is a paucity of available information in relation to environ-
mental hazards linked to VOCs given off by treated sludge, as evidenced by the
location of only one reference to literature through the Dialog search. An
EPA Project Summary document stated that volatile priority pollutant organics
were rarely detected.1 The document further stated that if VOCs were
detected, they were detected at a level far below toxic detection limits.
However, the sludge is not the prime source of VOCs and other gaseous
emissions in a land application system. The transportation of sludge and
lime generates the greatest volume of gases. Table 2 is a comparison of
estimates of gaseous emissions from land application and incineration of
73,000 DTPY of Blue Plains Sludge.
Table 2
Comparison of Emissions (Ibs/year)
Land Application vs. Incineration
(73,000 DTPY)
Pollutant
Land Application
(260.000 gpv of fuel)
Stack Emissions
Incineration
Ash Haul
(26.000 gpv of fuel)
TSP
S02
CO
NOX
voc
3,725
8,025
82,250
59,900
13,200
84,000
240,000
Negligible
498,000
30,000
400
1,000
8,230
6,000
1,300
84,400
241,000
8,230
504,000
31,300
Source: 8,
The Table shows that the transportation of sludge will result in
higher carbon monoxide emissions than incineration, but otherwise incineration
is the greater source.
To further analyze the impact of transporting 200 DTPD of Blue
Plains Sludge to land application sites, the Air Programs Planning Section of
the U.S. EPA, Region III completed an analysis of the air quality impact of
diesel truck exhaust. They determined that the impact of hydrocarbons, carbon
monoxide, nitrogen oxides, and particulates will be insignificant.
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The following information, provided by EPA, Region III was used to
complete the analysis:
1986 Mack 686 ST diesel trucks
80 trips per day (a highly conservative estimate)
Operating 8 hours per day
Idling 2 hours per day
Average trip is 150 miles round trip
The analysis was made assuming the area of impact to be the National
Capital Interstate Air Quality Control Region (AQCR), which is defined to
include: Montgomery and Prince George's Counties in Maryland, the District of
Columbia, and Arlington, Fairfax, Loudoun and Prince William Counties in
Virginia.
The emission factors for the heavy duty diesel trucks were calcu-
lated using the fourth edition of AP-42, Compilation of Air Pollutant Emission
Factors, Volume II: Mobile Sources. The basic and idle emissions were
determined on a gram per day basis and summedvto get a total emission for each
pollutant; specifically hydrocarbons, carbon monoxide and nitrogen oxides.
These values were converted to tons per day based upon 80 trips per day and a
150 mile trip. Then these values were compared to the estimated 1987 mobile
emissions inventory found in the Final Washington Metropolitan Air Quality
Plan for Control of Ozone and Carbon Monoxide, Appendices, Volume I, December
1982 which was prepared by the Metropolitan Washington Council of Governments
as part of the 1982 State Implementation Plan revision (SIP) for the National
Capital Interstate AQCR.
Based on the 1987 mobile source inventory, the diesel truck emis-
sions generated by the Blue Plains proposal are estimated to be 0.04% and
0.08% of the total emissions of hydrocarbons and nitrogen oxides, respec-
tively. Therefore, the hydrocarbon and nitrogen oxide emissions appear to be
insignificant. The total carbon monoxide emissions were calculated to be 0.01
tons per day. The 1982 SIP revision analyzed carbon monoxide on a "hot spot"
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level and therefore cannot be used for comparison with the calculated emission
values. 'However, the carbon monoxide emissions are very small and appear to
be insignificant in impact.
The particulate emissions were estimated to be 0.22 tons per day.
These estimates were made using the report entitled Size Specific Total
Particulate Emission Factors for Mobile Sources, prepared by Energy and
Environmental Analysis, Inc. for EPA, August 1985. Diesel particulates are
very small (less than 10 microns in size (PM-10)). There is no emissions
inventory for PM-10 in the National Capital AQCR. In 1970, the District of
Columbia submitted a SIP for total suspended particulates. This emissions
inventory cannot be compared with the calculated particulate emissions because
the SIP inventory is over 18 years old, only covers the District of Columbia
and not the entire AQCR, and because the inventory includes those particulates
larger than 10 microns in size. In conclusion, the particulate emissions are
very small and appear to be insignificant in impact.
It should be noted that the calculated emissions discussed herein
are estimates. The MOBILES mobile source model was used to make the calcula-
tions. However, in the 1982 SIP which was used for comparison, the 1987
mobile emission inventory was estimated using MOBILE2, an outdated version of
the mobile source model.
Summary
The results of a literature search and two sludge transport
emissions analyses show that the environmental impacts of gaseous emissions
from a sludge land application program are insignificant. Carbon monoxide was
the only gas from a land application program which exceeds the projected
emissions from the incineration alternative. However, even the carbon
monoxide emissions were described in an EPA analysis as insignificant in
impact.
Emissions from sludge are minor, including VOC emissions. Addi-
tional emissions from sludge transporting the sludge appear to be insignifi-
cant in terms of their impacts upon air quality in the Washington area.
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E. ENERGY CONSUMPTION
1. Energy Consumption
The land application and incineration-ash landfilling sludge manage-
ment alternatives consume various types of energy for system operation and by
design each supplements energy consumption of other processes. Comparing the
energy usage of land application and incineration has generally shown energy
use to be a very important alternative selection parameter for information
while it is not important in selecting land application^. Both alternatives
consume electrical power for dewatering sludge, but the incineration dewater-
ing power consumption is greater due to the system complexity and higher
degree of dewatering required. The incineration process as proposed would use
460,000 SCF of digester gas per day, 60,000 gallons of No. 2 fuel oil for
startup fuel and the combustible fraction (65%) of the dewatered sludge which
has a heating value of about 5,850 BTUs/lb. The electrical power expected to
be generated from the incineration process auxiliary equipment is 48,000
kwhr/day. The land application program as proposed would use about 669,000
gal/yr of diesel fuel. Also, through replacement of commercial fertilizer
with equivalent sludge nutrient value, fertilizer production energy require-
ments would be offset.
Based on the information available, an energy summary of each
alternative was developed as shown in Table 3. The dewatering and incinera-
tion energy cost data came from the EIS and ES* reports excluding ash trans-
portation which was adjusted to be on a similar basis as sludge transporta-
tion. The land application energy costs were based on information supplied by
the current District sludge hauling contract operators. A review of the total
dollar value of the input energy for the alternatives indicates there is an
energy savings of about $770,700/yr if land application were used in place of
incineration-ash landfilling.
* Engineering Science - Consultant to D.C. to provide concept design for the
incineration alternative.
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Table 3
Summary of Energy Cost (1)
Four Unit Land
Energy Item Incineration Application
Dewatering
Electrical Power
Filter Press $ 541,000
Centrifuge $ 310,000
Incineration
Electrical Power $ 624,300
Startup Fuel 61,700
Digester Gas Value (2) 503,700
Ash Transportation Fuel (3> 19.000
Subtotal $1,208,700
Land Application N/A
Sludge Transportation and
Spreading Fuel (4) $ 669,000
Total $1,749,700 $ 979,000
(1) Based on information in the EIS as based on ES reports and other sources.
(2) Based on 460,000 SCFD digester gas requirement valued at $3/1000 CF.
(3) Based on 88 DTPD, 50% solids, 1.25 T/CY, 50 mile round trip, 5 MPG, 27
CY/truck and $l/gal. fuel.
<4> Based on 73,000 DTPY, 21% solids, 18,250 DTPY post lime, 0.825 T/CY, 160
mile round trip, 5 MPG, 27 CY/truck, $l/gal. fuel, tractor and loader 8
gal/hr, 90 hrs/wk, spreader 1 gal/hr, 70 hrs/wk, 20 minute cycle time, and
10% additional for miscellaneous and support vehicle fuel.
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Each of the alternatives has an offsetting energy output which
should also be considered. The 48,000 kwhr/day of electrical power generated
by the incineration auxiliary equipment has an estimated market value of
$808,000/yr. The estimated average fertilizer value for the Blue Plains
sludge is $45.17/dry ton applied which results in a total annual market value
of $3,297,000. While the total annual market values indicate land application
has the higher offsetting value, it is important to consider the market value
of the end product includes other non-energy cost factors.
A comparison of the offsetting energy outputs of each alternative
based on the number of therms/day(*) provides a more direct result. The
incineration electrical power therms/day equivalent was determined to be
1,638. The energy to produce a ton of nitrogen fertilizer has been reported
to require 44,760 SCF of natural gas, 150 kwhr of electricity and 8.95 gallons
of fuel oillO. Based on this information, the land application alternative
equivalent therms/day was determined to be at least 3,462 and excludes the
additional energy to provide the phosphorus, potassium, and lime fertilizer
components. Land application again has a higher offsetting energy component
than incineration when the therms/day are compared.
2. Summary
In summary, the land application alternative appears to have a lower
energy input dollar cost and a higher offsetting energy component than the
incineration-ash landfilling alternative.
F. Land Purchase/Leasing
1. Land Purchase/Leasing
One of the factors in considering land application is both the
availability of land and the cost of that land. In most land application
programs, land value is not a factor since the land owner provides the use of
(*) 1 therm - 100,000 Btus
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the land for sludge disposal purposes. However, land purchase for land
application of sewage sludges is grant eligible.
However, the consideration in this section is the potential cost of
land either on a purchase or rental basis. Table 4 provides a comparison of
approximate cost on both a rental or purchase basis for land in selected
counties in Virginia and Maryland.
The purchase or rental/lease of land for sludge disposal is not the
normal practice. For instance, the purchase of land by one community within
another may create public distrust and opposition in the host community, could
impact local tax revenues and could present other legal obstacles.
The purchase or lease of lands for wastewater or solids disposal is
grant eligible and has been done many times across the country. However, as
Table 4 indicates, the rental or leasing of agricultural land on an annual
basis is far less expensive than purchasing the land.
2. Summary
Land application processes should not consider rental/leasing or
purchase of land. Sufficient land is currently permitted and leasing/purchase
arrangements could send the wrong signals to those counties who are currently
participating in land application programs.
G. Lorton Landfill Capacity
The Lorton Landfill or 1-95 Landfill, as it is locally known, is owned
and operated by Fairfax County, Virginia. In conversations with the Fairfax
County Division of Solid Waste regarding the operation of this facility, the
following information was offered:
o Without implementation of the resource recovery facility (1-95
energy recovery facility) at Lorton, the landfill will reach
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Table 4
Summary of Land Costs for Sludge
Land Application Sites (1)
Number of
State County Permitted Acres Local Contact
Maryland Howard 2,916 Roberta Weber
(301) 992-2030
Prince Georges 9,077 David Conrad
(301) 868-8783
Queen Ames 5,922 Paul Gunther
(301) 758-0166
Talbot 3,982 Don Osburn
(301) 822-1244
Aver)
Virginia Caroline 2,875 Dan Moody
(804) 633-6550
Essex 9,575 Keith Balderson
(804) 443-3551
Fauquier 5,301 W. C. Broun
(703) 347-8650
Goochland 3,297 Jim Grove
(804) 556-5341
Hanover 6,699 Timothy Ethridge
(804) 537-6030
Loudoun 4,596 Gary Hornbaker
(703) 478-1852
Approximate
Rental Cost
Agricultural
Land $/ac
30-45
65
_§5
ige 58
60
30-45
20-60
15-60
35-40
3-35
Approximate
Purchase Cost
Agricultural
Land $/ac (2)
1,900 - 3,800
2,000 - 5,000
2.700 - 4.000
3,233
800 - 1,500
1,200 (Non Water
Front)
1,800 - 10,000 (2)
500 - 1,200
2,000 - 5,000
3.500
Average 39
2,000 (2)
(1) Based on land prices provided by county extension agents.
(2) The higher range values Mere reported to represent agricultural land being sold for development.
(3) Average excludes Fauquier County high range value.
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capacity in the mid 1990's. However, once the resource recovery
operation is in operation, the capacity should be expanded by 10-15
years.
Average daily intake at the landfill is currently 5,000 tons/day.
Ash is currently being disposed at Lorton. Ash comes from the
Arlington Resource Recovery facility and sludge incinerator ash from
Fairfax County.
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SOURCES
1. Telephone conversation with Mr. Robert Pepperman, Enviro-Gro Tech-
nologies, January 5, 1989.
2. Telefax from Mr. Timothy Ford, Ad + Soil, January 16, 1989.
3. Telefax from Ms. Carol Pavon, BioGro Systems, January 17, 1989.
4. Telephone conversations with Mr. Paul Farrell, Virginia Department of
Health, January 5 and 10, 1989.
5. Telephone conversations with Mr. Doug Proctor, Maryland Department of the
Environment, Manuary 5 and 12, 1989.
6. Environmental Profiles and Hazard Indices for Constituents of Municipal
Sludge, US EPA, June 1985.
7. "Trace Organics and Inorganics in Distribution and Marketing Municipal
Sludges, " US EPA 600/51-88/001, 1988.
8. Written communication from John E. Touchstone, Director, D.C. Department
of Public Works, to Greene A. Jones, Director, Environmental Services
Division, US EPA, December 9, 1988.
9. EPA 625/10-84-003 Technology Transfer, Environmental Regulations and
Technology, Use and Disposal of Municipal Wastewater Sludge, September
1984, Pg. 61.
10. Energy requirements for New York State Agriculture Part II Indirect
Energy Inputs, Agricultural Engineering Extension Bulletin, Cornell
University.
11. Telephone conversation with Mr. James Maglione, Division of Solid Waste,
Department of Public Works, Fairfax County, Virginia, December 20, 1988.
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