&EPA
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 2771 1
EPA-600/7-80-012a
January 1980
Waste and Water
Management for
Conventional
Coal Combustion
Assessment Report -1979
Volume I.
Executive Summary
Interagency
Energy/Environment
R&D Program Report
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from the
effort funded under the 17-agency Federal Energy/Environment Research and
Development Program. These studies relate to EPA's mission to protect the public
health and welfare from adverse effects of pollutants associated with energy sys-
tems. The goal of the Program is to assure the rapid development of domestic
energy supplies in an environmentally-compatible manner by providing the nec-
essary environmental data and control technology. Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
effects; assessments of, and development of, control technologies for energy
systems; and integrated assessments of a wide range of energy-related environ-
mental issues.
EPA REVIEW NOTICE
This report has been reviewed by the participating Federal Agencies, and approved
for publication. Approval does not signify that the contents necessarily reflect
the views and policies of the Government, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/7-80-012a
January 1980
Waste and Water Management
for Conventional Coal Combustion
Assessment Report -1979
Volume I. Executive Summary
by
C. J. Santhanam, R. R. Lunt, C. B. Cooper,
D. E. Kleinschmidt, I. Bodek, and W. A. Tucker (ADD;
and C. R. Ullrich (University of Louisville)
Arthur D. Little, Inc.
20 Acorn Park
Cambridge, Massachusetts 02140
Contract No. 68-02-2654
Program Element No. EHE624A
EPA Project Officer: Julian W. Jones
Industrial Environmental Research Laboratory
Office of Environmental Engineering and Technology
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
-------
PARTICIPANTS IN THIS STUDY
This First Annual R&D Report is submitted by Arthur D. Little, Inc.
to the U. S. Environmental Protection Agency (EPA) under Contract No.
68-02-2654. The Report reflects the work of many members of the
Arthur D. Little staff, subcontractors and consultants. Those partici-
pating in the study are listed below.
Principal Investigators
Chakra J. Santhanam
Richard R. Lunt
Charles B. Cooper
David E. Kleinschmidt
Itamar Bodek
William A. Tucker
Contributing Staff
Armand A. Balasco Warren J. Lyman
James D. Birkett Shashank S. Nadgauda
Sara E. Bysshe James E. Oberholtzer
Diane E. Gilbert James I. Stevens
Sandra L. Johnson James R. Valentine
Subcontractors
D. Joseph Hagerty University of Louisville
C. Robert Ullrich University of Louisville
We would like to note the helpful views offered by and discussions
with Michael Osborne of EPA-IERL in Research Triangle Park, N. C., and
John Lum of EPA-Effluent Guidelines Division in Washington, D. C.
Above all, we thank Julian W. Jones, the EPA Project Officer, for
his guidance throughout the course of this work and in the preparation
of this report.
iii
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ACKNOWLEDGEMENTS
Many other individuals and organizations helped by discussions with
the principal investigators. In particular, grateful appreciation is
expressed to:
Aerospace Corporation - Paul Leo, Jerome Rossoff
Auburn University - Ray Tarrer and others
Department of Energy - Val E. Weaver
Dravo Corporation - Carl Gilbert, Carl Labovitz, Earl Rothfuss
and others
Electric Power Research Institute (EPRI) - John Maulbetsch,
Thomas Moraski and Dean Golden
Environmental Protection Agency, Municipal Environmental Research
Laboratory - Robert Landreth, Michael Roulier, and Don Banning
Federal Highway Authority - W. Clayton Ormsby
IU Conversion Systems (IUCS) - Ron Bacskai, Hugh Mullen
Beverly Roberts, and others
Louisville Gas and Electric Company - Robert P. Van Ness
National Ash Association - John Faber
National Bureau of Standards - Paul Brown
Southern Services - Reed Edwards, Lamont Larrimore, and Randall Rush
Tennessee Valley Authority (TVA) - James Crowe, T-Y. J. Chu,
H. William Elder, Hollis B. Flora, R. James Ruane,
Steven K. Seale, and others
iv
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CONVERSION FACTORS
English/American Units
Length:
1 inch
1 foot
1 fathom
1 mile (statute)
1 mile (nautical)
Area:
1 square foot
1 acre
Volume:
1 cubic foot
1 cubic yard
1 gallon
1 barrel (42 gals)
Weight/Mass:
1 pound
1 ton (short)
Pressure:
1 atmosphere (Normal)
1 pound per square inch
1 pound per square inch
Concentration:
1 part per million (weight)
Speed:
1 knot
Energy/Power:
1 British Thermal Unit
1 megawatt
1 kilowatt hour
Temperature:
1 degree Fahrenheit
Metric Equivalent
2.540 centimeters
0.3048 meters
1.829 meters
1.609 kilometers
1.852 kilometers
0.0929 square meters
4,047 square meters
28.316 liters
0.7641 cubic meters
3.785 liters
0.1589 cu. meters
0.4536 kilograms
0.9072 metric tons
101,325 pascal
0.07031 kilograms per square centimeter
6894 pascal
1 milligram per liter
1.853 kilometers per hour
1,054.8 joules
3.600 x 10^ joules per hour
3.60 x 106 joules
5/9 degree Centigrade
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GLOSSARY AND ABBREVIATIONS
GLOSSARY
Cementitious: A chemically precipitated binding of particles
resulting in the formation of a solid mass.
Fixation; The process of putting into a stable or unalterable
form.
Impoundment; Reservoir, pond, or area used to retain, confine,
or accumulate a fluid material.
Leachate; Soluble constituents removed from a substance by the
action of a percolating liquid.
Leaching Agent: A material used to percolate through something
that results in the leaching of soluble constituents.
Pozzolan; A siliceous or aluminosiliceous material that in
itself possess little or no cementitious value but that in
finely divided form and in the presence of moisture will react
with alkali or alkaline earth hydroxide to form compounds possessing
cementitious properties.
Pozzolanic Reaction; A reaction producing a pozzolanic product.
Stabilization; Making stable by physical or chemical treatment.
vi
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ABBREVIATIONS
Btu British thermal unit
cm centimeter
cm/sec centimeter per second
°C degrees Centigrade
°P degrees Fahrenheit
ESP electrostatic precipitator
FGC flue gas cleaning
FGD flue gas desulfurization
ft feet
ft/sec feet per second
g gram
gal gallon
gpm gallons per minute
hp horsepower
hr hour
in. inch
j joule
j/s joule per second
k thousand
kg kilogram
km kilometer
kW kilowatt
kWh kilowatthour
1 liter
Ib pound
M million
n>2 square meter
n>3 cubic meter
MW megawatt
ppm parts per million
psi pounds per square inch
sec second
IDS total dissolved solids
Note: For conversion unita, see pagev.
vii
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VOLUME 1: EXECUTIVE SUMMARY
TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS iii
CONVERSION TABLE v
GLOSSARY AND ABBREVIATIONS vi
LIST OF TABLES x
LIST OF FIGURES xi
1.0 INTRODUCTION 1-1
2.0 EPA's WATER AND WASTE PROGRAM 2-1
3.0 PURPOSE AND ORGANIZATION OF THIS REPORT 3-1
3.1 Scope of Contract 3-1
3.2 Purpose 3~2
3.3 Organization of this Report 3-3
4.0 SUMMARY AND CONCLUSIONS 4-1
4.1 Overview 4-1
4.2 Regulatory Considerations 4-3
4.3 Water Recycle/Treatment/Reuse 4-12
4.3.1 Effluent Streams 4~14
4.3.2 Water Management 4-15
4.3.3 Data Gaps and Future Research Needs 4-18
4.4 FGC Wastes Overview 4-19
4.5 Characterization of FGC Wastes 4-21
4.5.1 Chemical Characteristics 4-21
4.5.2 Physical Properties 4-31
4.5.3 Research Needs in Characterization 4-35
4.6 FGC Waste Disposal 4-35
4.6.1 Impact Issues 4-35
4.6.2 Disposal Options and Potential Impacts 4-36
4.6.2.1 Land Disposal 4-38
4.6.2.2 Ocean Disposal 4-44
4.6.3 Potential Impacts 4-45
4.6.4 Impact Control Measures 4-47
viii
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VOLUME 1: TABLE OF CONTENTS
Page
4.6.5 Future Research Needs 4-50
4.6.6 Economics of FGC Waste Disposal 4-53
4.6.6.1 Costs of Waste Disposal
Alternatives 4-54
4.6.6.2 Economic (Cost) Impact
Studies 4-61
4.6.6.3 Economic Uncertainties
and Data Gaps 4-62
4.7 FGC Waste Utilization 4-63
4.8 Emerging Technologies and the Future 4-66
References
ix
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LIST OF TABLES
Table Page
S.I Projects in the Waste and Water Program 2-2
S.2 Federal Regulatory Framework for Disposal
of FGC Wastes and Water Effluents 4-4
S.3 Discharge Limits for the Utility Industry 4-6
S.4 Water Used for Electric Utility Generation
of Thermoelectric Power in Million Gallons
Per Day, By Regions, 1975 4-13
S.5 Projected Generation of Coal Ash and FGC Wastes 4-20
S.6 Composition of Coal Ash According to Coal Rank 4-22
S.7 Major Components in FGC Waste Solids 4-24
S.8 Range of Trace Species Present in Coal Ash 4-26
S.9 Total Concentration of Trace Constituents in
FGC Waste and Coal 4-28
S.10 Typical Concentration Ranges of Chemical
Species in FGC Waste Liquors and Elutriates 4-29
S.ll Physical and Engineering Properties of Fly Ash 4-32
S.12 Physical and Engineering Properties of FGC Waste 4-33
S.13 Potential Disposal Options 4-37
S.14 Present Disposal Practices Utility FGC Systems 4-39
S.15 Summary of Current Field Testing Program for
FGC Wastes Disposal 4-40
S,16 Disposal Options VS Impact Issues 4-46
S.17 Summary of General Conceptualized Cost Studies 4-55
S.18 Summary of TVA Cost Estimates for FGC Waste Disposal 4-57
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LIST OF FIGURES
Figures Page
S.I EPA Program Overview Technology Control Waste
and Water Pollution From Combination Sources 2-5
S.2 Generalized Schematic Water Balance for a
Typical 1000 MW Coal-Fired Power Plant 4-16
xi
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1.0 INTRODUCTION
Modern fossil-fueled boilers employing conventional coal combustion
(utility boilers and large industrial boilers) present a broad spectrum
of potential environmental problems. In recent years the development of
regulatory constraints pertaining to air and water pollution control have
required and will continue to require focus on the environmental manage-
ment of solid wastes and effluents.
A coal-fired utility or industrial boiler produces two broad
categories of wastes.
a. Solid wastes, principally
- fly ash
- bottom ash (or boiler slag)
- flue gas desulfurization (FGD) wastes
The predominant part of the solid wastes, excluding
bottom ash, are generated by the use of air pollution
control devices - electrostatic precipitators, bag-
houses, and scrubbers - to control emissions of fly
ash and sulfur dioxide (S0_). Although there are
other wastes, such as those from water treatment
systems, the quantities of these are small compared
to the large amounts of ash and SO- scrubber waste
produced. Together, coal ash and FGD wastes are
generally referred to as flue gas cleaning (FGC) wastes.
In many cases, fly ash and SO emissions are separately
controlled and represent separate waste streams. In
other cases, fly ash and FGD wastes are combined in a
single stream, either through admixture of these wastes
or through simultaneous collection of fly ash and S02«
b. Wastewater effluents from several sources in the power
plant. The major use points for water and, hence,
generation points for effluents are:
I. Continuous:
1-1
-------
• condenser cooling
• steam generation
• water treatment
• ash handling
• flue gas desulfurization
• miscellaneous
II. Intermittent:
• maintenance cleaning
• drainage (including coal pile runoff)
The multiplicity of uses of water in a power plant and
the widely varying requirements for water quality in
those uses present power plants with major opportunities
for water management through a combination of:
- Wastewater management by recycle. For example, boiler
blowdown is often of higher purity than original supply
and can be used at many points.
- Combination of compatible streams with appropriate
equalization. Ash pond and coal-pile runoff may help
neutralize each other.
- Treatment of appropriate streams for reuse or discharge.
c. Furthermore in the future increasing emphasis on water
recycle/treatment/reuse will generate some increasing
amounts of solid wastes with potentially hazardous
pollutants.
Optimum management of the potential environmental problems associated
with the above two categories requires an integrated approach to the
problem of waste and water pollution at power plants or industrial boilers
The environmental legislation of the past few years and that which
is now emerging, provides for the regulation of waste and water pollution
from combustion sources. However, a major reduction in pollution in one
medium (e.g., air) for a given pollution control requirement will lead
to an increase in the level of pollutants in the other media (water, land)
1-2
-------
Hence, a key element in environmental management is dealing with such
"cross-media" impacts. Recognizing this, the regulatory framework re-
quires the U. S. Environmental Protection Agency (EPA) to assist in the
development and application of technology to minimize the potential
adverse environmental impacts from such regulatory requirements. In the
case of waste and water pollution control from combustion sources, a
number of research, development and demonstration efforts have been
required. The need for these has been the basis for the formulation of
EPA's program concerning technology for control of waste and water pollu-
tion from combustion sources or briefly, the Waste and Water Program.
In addition to EPA, Electric Power Research Institute (EPRI), several
utilities and others have been active in this field.
Since 1974, the U. S. Environmental Protection Agency (EPA) has been
conducting a program for environmental management of solid wastes and
effluents from steam-electric generating plants. EPA programs like other
programs on waste and water pollution control from power plants has
focused principally on coal-fired power plants for two reasons:
1. Coal-fired plants offer the broadest and most complex
environmental management problems. Technology transfer
to other fossil fuels, where necessary, is more easily
achieved than with any other fuel.
2. The nation is anticipated to rely increasingly on coal
as a primary fossil-fuel for energy.
1-3
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2.0 EPA's WASTE AND WATER PROGRAM
The objectives of the Waste and Water Program are to evaluate,
develop, demonstrate and recommend environmentally acceptable, cost-
effective technology for:
• Flue Gas Cleaning (FGC) Waste Disposal/Utilization; and
• Power Plant Water Recycle/Treatment/Reuse.
EPA's Waste and Water Program is divided into five major areas, three
of which are relevant to the scope of this report:
a. FGC Waste Disposal
b. FGC Waste Utilization
c. Water Utilization/Treatment
d. Cooling Technology
e. Waste Heat Utilization
Each of these program areas includes a number of projects; these are
listed in Table S.I. It should be noted that EPA projects pertaining to
cooling technology or waste heat utilization are outside the scope of
this report and hence not listed. The FGC Waste Disposal area of the
Waste and Water Program consists of 19 projects, 5 of which were
recently completed.
An overview of how some of these programs fit into power plant
systems are shown in Figure S.I.
EPA's Waste and Water Program principally focuses on coal-fired
utility boilers at present. Coal-fired plants (vis-a-vis oil or gas)
generate the maximum range of wastes and present the most complex water
management problems. Further, there is universal consensus that coal
utilization in the United States is going to increase significantly in
the years to come. From the viewpoint of technology for waste and water
pollution control, coal-fired plants are the logical choice. While the
present focus is on utility power plants, EPA's focus in the years to
come will also be on large industrial boilers.
2-1
-------
Tabl.i S.I
Projects in the Waste and Water Program
Basis: Excludes those pertaining to cooling technology and waste heat utilization
Project Title
FCC WASTE DISPOSAL
1. Assessment of Technology for
Control of Waste and Water
Pollution
2. FGC Waste Characterization,
Disposal Evaluation, and Transfer
of FCC Waste Disposal Technology
3. Solid Waste Impact of Controlling
SO. Emissions from Coal-Fired
Steam Generators
4. Lab and Field Evaluation of 1st
and 2nd Generation FGC Waste
Treatment Processes
5. Ash Characterization and
Disposal
6. Studies of Attenuation of FGC
Waste Leachate by Soils a
7. Establishment of Data Base for
FGC Haste Disposal Standards
Development
8. Development of Toxics Speciation
Model and Economic Development
Document for FGC Waste Disposal
9. Shawnee FGC Waste Disposal Field
Evaluation
10. Louisville Gas and Electric
Evaluation of FGC Waste Disposal
Options
11. FGC Waste Leachate-Liner
Compatibility Studies
12. Lime/Linestone Wet Scrubbing
Waste Characterization and Dis-
posal Site Revegetation Studies
Contractor/Agency
Arthur D. Little, Inc.
The Aerospace Corp.
The Aerospace Corp.
U. S. Army Corps of
Engineers (Waterways
Experiment Station)
Tennessee Valley
Authority
U. S. Army Test & Evaluation
Command (Dugway Prov. Ground)
Stearns, Conrad and Schmidt
Consulting Engineers. Inc.
(SCS Engineers)
SCS Engineers
Tennessee Valley Authority
The Aerospace Corporation
Louisville Gas & Electric
(Subcontractor: Combustion
Engineering, Inc.)
U. S. Army Corps of
Engineers (Waterways
Experiment Station)
Tennessee Valley Authority
Tech.
Environ. Assess, i Econ. Charac.
Assess. Develop. Assess. Studies
Current
Status
Ongoing
Completed
Completed
Ongoing
Ongoing
Completed
Completed
Completed
Ongoing
Completed
Ongoing
Ongoing •
13. Development of EPA Pilot Plant
Test Flan Co Relate FGC Waste
Properties to Scrubber Operating
Variables*
Radian Corporation
Completed
*. Dirtct Support of Regulation Development
-------
Table S.I (Continued)
Projects In the Waste and Water Program
Project Title
FGC WASTE DISPOSAL (Continued)
14. Oewaterlng Principals and Equip-
ment Design Studies
IS. Conceptual Design/Cost Study
of Alternative Methods for Lime/
Limestone Scrubbing Waste Disposal
16. Evaluation of FGC Waste Disposal
In Mines and the Ocean
17. Evaluation of Power Plant
Wastes for Toxicity as Defined
by RCRA
18. Study of Non-Hazardous Wastes
from Coal-Fired Electric Utilities
19. Selection of Representative Coal
Ash & Coal Ash/FGD Waste Dis-
posal Sites
20. Characterization & Environmental
Monitoring of Full-Scale Waste
Disposal Sites
FGC WASTE UTILIZATION
1.
Gypsum Byproduct Marketing
Studies
2. Pilot Studies of a Process for
Recovery of Sulfur and Calcium
Carbonate from FGC Waste
3. Fertilizer Production Using Lime/
Limestone Scrubbing Wastes
4. Use of FGC Waste in a Process
for Alumina Extraction from
Low-Grade Ores
HATER UTILIZATION/TREATMENT
1. Assess Power Plant Water Recycle/
Reuse
2. Pilot Demonstration of Water
Recycle/Reuse
3. Characterization of Effluents
from Coal-Fired Power Plants
4. Water Pollution Impact of
Controlling SO, Emissions from
Coal-Fired Steam Generators a
5.
Treatment of Power Plant Wastes
with Membrane Technology
Contractor/Agency
Auburn University
Tennessee Valley
Authority
Arthur D. Little, Inc.
Radian Corporation
Department of Energy
(Oak Ridge Natl lab)
Radian Corporation
Versar
Contractor not yet
selected
T^r.nesoec Valley
Ajthority
Pullman-Kellogg
Tennessee Valley
Ai thority
TRW, Inc.
Radian Corporation
Contractor not yet
Selected
Tennessee Valley
Authority
Radian Corporation
Tennessee Valley
Authority
Tech.
Environ. Assess. & Econ.
Assess. Develop. Assess.
Charac. Current
Studies Status
Ongoing
Ongoing
Ongoing
Ongoing
Completed
Completed
Completed
Completed
Completed
Ongoing
Completed
Ongoing
Direct Support of Regulation Development
-------
Table S.I (Continued)
Projects In the Waste and Water Program
Project Title
WATER UTILIZATION/TREATMENT (Continued)
6. Power Plant Cooling Tower
Slowdown Recycle by Vertical Tube
Evaporator with Interface Enhance-
ment
Contractor/Agency
University of California-
Berkeley
Tech.
Environ. Assess. & Econ.
Assess. Develop. Assess.
Charac. Current
Studies Status
Ongoing
7. Treatment of Flue Gas Scrubber
Waste Streams with Vapor Compression
Cycle Evaporation a
8. Alternatives to Chlorination for
Control of Condenser Tube
Biofouling
9. Assessment of the Effects of
Chlorinated Seawater from Power
Plants on Aquatic Organisms
10. Bromine Chloride - An Alternative
to Chlorine for Fouling Control
in Condenser Cooling Systems a
11. Evaluation of Lime Precipitation
for Treatment of Boiler Tube
Cleaning Waste a
12. Assessment of Technology for
Control of Toxic Effluents from
the Electric Utility Industry8
13. Field Testing/Lab Studies for
Development of Effluent Standards
for Electric Utility Industry a
14. Effects of Pathogenic and Toxic
Material Transported via Cooling
Device Drift
15. Assessment of Measurement
Techniques for Hazardous Pollution
from Thermal Cooling Systems
16. Assessing Comparative Merits of
R.O., VCE and VTFE for Cooling
Tower Slowdown
Resources Conservation Co.
Monsanto Research
Corporation
TRW, Inc.
Martin Marietta
Corporation
Hittmen Associates, Inc.
Radian Corporation
Radian Corporation
H2M, Inc.
Lockheed Electronics Co.
Northrop Corporation
Bechtel, National
Completed
Completed
Completed
Completed
Completed
Ongoing
Ongoing
Ongoing
Direct Support of Regulation Development
-------
fV-X ft&M hA
COtXtCTOft * FCY *6H
O*>*
B C
A. __ U-HU1V _ -..c. ' O Sl»*V
COAA. ~ -111* povwtR " * ™1L * SCOUftfcWc.
PUkMT e*™
t
«• 1
M4D l-BSOKBfcMTJ
TR&MttAtXT
• Characterization of • Fly ash character!- • Lime and Liina-
effluents from coal- zation and disposal stone scrubbing
fired power plants (TVA), C.M.H. waste character-
(TVA), A.C.L. ization (TVA),
• Assess and demon- D.E.. j ^
strate power plant ' *
water reuse/recycle
(Radian), L.B.K.
• Renovate cooling
tower blowdovn by
vertical tube
evaporator (U of
Cal.). L.
m Evaluate uiie nf
vapor compression
Evaporator to re-
duce water pollu-
tion from FCD
processes (RCC).L.
' i
Mt» F "Z wk*T6 «- w5T?T,^«f
OfcWME*. TUtMWkWlT
.[ "
DISPOSE
uauom.
V9 !
LIOUOK. C.OUO Wa&TF
PROCESSIH&
J
iniuz.*.t
,
• Assessment of • Laboratory and •
waste & water field evaluation
program (ADLittle) of FGC treatment
E. - ,C,H,K,L,M, processes (U.S.
1'2'i Army UESKC.F.j.H
• Devatering ^ Evaluation of FGC
Principals and waste dt t
equipment design * }
studies (Auburn U) , K
- G.H.
h' •
• Conceptual
design and cost
studies of alter-
native methods
for lime and lime- e
s.one scrubbing
waste disposal
(TVA), C.H.
• Lime and Lime-
stone scrubbing •
waste conversion
pilot studies
(Pullman-Kellogg)
• Fertilizer pro- •
ductlon using
lime and limestone
Assessment of waste
and water program
(ADD, E
C.H.K.L.R: *
Shawnee FCD Waste
Disposal field eval-
uation (TVA and
Aerospace). H.G.Ej.
Attenuation of FCC
waste leachate by
soils (U.S. Army,
Dugway), H.
Establishment of
data base for foe
waste disposal
standards develop-
ment (SCS Engr) H.
Alternative disposal
methods development
(A. D. Little)
H>E1.2,C-
FGC waste leachate
liner compatibility
(U.S. Army WES).H.
•1
l»»*
scrubbing wastes
(TVA). 1.3. • FGD waste and fly
ash beneficlation
studies (TRW). J.I.
• Gypsum byproduct
marketing studies
(TVA).
• Environmental Effects
and control of various
FGC sludge disposal
options (SCS Engr),
H, E1PC.
• Study of non-hazardous
wastes (Radian)
Source: Arthur D.Little. Inc.
Figure S.I EPA Program Overview Technology Control
Waste and Water Pollution Frow Combination
Sources
-------
3.0 PURPOSE AND ORGANIZATION OF THIS REPORT
3.1 Scope of Contract
The purpose of Arthur D. Little's contract with the EPA (Contract
No. 68-01-2654) is to assemble, review, evaluate, and report data from
research and development as well as commercial activities in the areas
of:
a. Flue Gas Cleaning Waste Disposal/Utilization; and
b. Power Plant Water Management including Recycle/Treatment/
Reuse.
These efforts are conducted to assist the EPA in conducting an ongoing
program of research and development in the above-mentioned areas. Results
of these efforts are required to be reported annually.
The focus of this effort is:
• Evaluation of the technical, economic, regulatory and
environmental aspects of FGC waste disposal/utilization,
with particular emphasis on the effects of these factors
on the feasibilities and cost of various disposal/utiliza-
tion options. Where information gaps exist, recommenda-
tions are made on measures to fill these gaps, and, as
appropriate, conduct laboratory research to develop
additional data on FGC waste properties. The staff of
the Civil Engineering Department of the University of
Louisville, as a subcontractor to Arthur D. Little, will
conduct testing of FGC waste engineering properties and
has been assisting Arthur D. Little in the review and
evaluation of engineering and physical properties data.
c Evaluation of the technical, economic, regulatory and
environmental aspects of power plant water recycle/treat-
ment/reuse, where information gaps exist, recommendations
will be offered for programs to fill these gaps.
3-1
-------
3.2 Purpose of this Report
This Assessment Report is the first of a series to assess the
technology for control of pollution from conventional coal-fired combus-
tion sources (utility plants and large industrial boilers). The purpose
of this report is to assemble, review, evaluate and report data from
research and development as well as commercial activities pertaining to
these areas. This report has two objectives:
• To assist the EPA in assuring an ongoing program of
research and development in the above-mentioned areas;
and
o To serve as a state-of-the-art report on Water Recycle/
Treatment/Reuse and Flue Gas Cleaning (FGC) Waste
Disposal/Utilization for power plants and large industrial
boilers.
The review and assessment effort underlying this report involved
review of the data and information available as of February 1979, on:
- water management and wastewater characterization and
treatment and assessment of current R&D studies,
- generation of FGC wastes, and chemical, physical and
engineering properties of FGC wastes,
- disposal options including current practice, R&D and
field studies on disposal and environmental/economic
assessment of disposal,
- utilization practice including technical and economic
assessment of current practice and R&D studies.
The review is based upon published reports and documents as well as
contacts with private companies and other organizations engaged in technoloe
development or involved in the design and operation of water and waste man-
agement systems and waste disposal or wastewater treatment facilities. Much
of the information has been drawn from the waste characterization studies
and technology development/ demonstration programs sponsored by the
Environmental Protection Agency (EPA) and the Electric Power Research
Institute (EPRI).
3-2
-------
Based upon the review of the data and assessment of ongoing work in
the above fields, identification of data and information gaps relating
to each of the above fields is made. The objective is to help potential
EPA initiatives in the future to close these gaps. Ultimately, adequate
data should be available to permit reasonable assessment of the impacts
associated with the disposal and/or utilization of FGC wastes and water
management at utility plants and industrial boilers.
Throughout this work, emphasis has been placed upon wastes produced
by commercially demonstrated technologies and, where data are available,
by technologies in advanced stages of development that are likely to
achieve commercialization in the United States in the near future. In
terms of FGD wastes, consideration is limited primarily to nonrecovery
FGD systems with focus on those producing solid wastes (rather than
liquid wastes). There are very few recovery systems in operation or
under construction in the United States, and these generally produce a
small quantity of waste in comparison to nonrecovery systems.
3.3 Organization of This Report
This is the first of at least three Assessment Reports that will be
produced under this contract. Since this is the first report in this
series, an extensive amount of background material has been included,
thereby establishing a basic source of technical information in this area.
The result is an 1100-page report on waste and water management for con-
ventional coal combustion. For the convenience of the reader, the report
is divided into five (5) volumes as follows:
• Volume 1 - Executive Summary. This volumes provides a
brief overview of the technical, economic and environ-
mental aspects of water and waste management associated
with coal-fired boilers.
• Volume 2 - Water Management. This volume describes water
management issues including:
3-3
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- An overview on water balances in coal-fired power plants
including coal-pile runoff, steam generation, main con-
denser cooling, flue gas desulfurization (FGD), ash
handling, equipment cleaning and water treatment.
- A brief account of existing wastewater-related regulations.
- An assessment of treatment technology currently available
or being developed for water recycle or reuse and treat-
ment technology for effluent discharge.
- Treatment methods for each stream, central treatment,
recycle and reuse possibilities and potential applica-
tion of advanced water treatment technology have been
considered.
- To the extent that data are available and generically
applicable, economic data have been reported. No
independent economic analysis was undertaken; rather,
reported costs were updated to mid-1978 using Chemical
Engineering Cost Index.
- Identification of data gaps and prioritization of the gaps
and some recommendations for potential EPA initiatives.
Volume 3 - Generation and Characterization of FGC Wastes.
This volume:
- Presents an overview on technology of coal ash
collection and flue gas desulfurization.
- Discusses production trends for FGC wastes.
- Assesses current dewatering technology.
- Describes stabilization processes.
- Discusses chemical, physical and engineering
characterization of FGC wastes, including non-
recovery flue gas desulfurization (FGD) wastes,
stabilized FGD wastes and coal ash.
- Identifies current data gaps.
3-4
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• Volume 4 - Utilization of FGC Wastes. This volume:
- Describes current commercial ash utilization.
- Describes and assesses current R&D program on
ash and FGD waste utilization.
- Identifies constraints on utilization.
• Volume 5 - Disposal of FGC Wastes. This volume:
- Describes current and potential disposal options.
- Assesses ongoing and proposed R&D programs on
technical, environmental and economic aspects of
FGC waste disposal.
- Identifies data gaps on environmental and economic
aspects of disposal practice.
3-5
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4.0 SUMMARY AND CONCLUSIONS
4.1 Overview
The various programs described in Section 2.0 have achieved
significant results in a number of areas. To date, the emphasis has
been on utility plants but in the future will also encompass industrial
boilers. Important accomplishments of EPA's Waste and Water Program,
EPRI's efforts and other work in this field include the following:
Overall Power Plant Water Management
Substantial progress has been made in characterizing all major waste-
water streams in a power plant. Overall water management studies
have shown that more efficient water recycle/reuse can in many cases
be achieved at reasonable costs. In particular, such studies can
serve as models for water management plans in new facilities.
Treatment systems to maximize water reuse are being evaluated
in EPA and privately funded studies and the improved evapora-
tive systems appear promising. Studies of effluent treatment
to remove priority pollutants listed under the Clean Water
Act of 1977 prior to discharge are also underway.
Flue Gas Cleaning (FGC) Waste Disposal
Chemical, physical and engineering properties of FGC wastes
have been characterized to a significant extent although some
data gaps remain. Progress in dewatering and stabilization
processes has opened up a variety of potential and currently
practiced disposal options. Preliminary environmental assess-
ment of a variety of disposal options has been completed although
environmental monitoring data from field scale projects (i.e.
full-scale disposal operations) are not currently available.
Recently announced projects by EPA and EPRI will go a long
way towards closing this data gap.
Areas for continuing evaluation relating to reducing costs
of FGC waste disposal have also been identified. These
include forced oxidation to gypsum, improved FGD dewatering
equipment, codisposal of ash and FGD wastes and
4-1
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stabilization processes. Processes for stabilization of FGD
wastes have been evaluated and appear suitable for environ-
mentally sound disposal. Studies on the use of liners in
FGC waste disposal operations have been undertaken and are
nearing completion.
The substantial amount of data on FGC waste characterization
and disposal gathered under the various programs provide a por-
tion of the technical baseline needed for the development of
RCRA related guidelines and regulations for FGC waste disposal.
FGC Waste Utilization
Technical studies point to further potential for ash and FGD
waste utilization provided regulatory or public policy con-
straints do not discourage utilization. The use of coal ash is
current commercial practice, although much greater utilization
is feasible. Production of salable FGD gypsum is technically
and economically feasible, given a proper match of power plant
and manufacturing plant (e.g., for wallboard, cement). However,
institutional and other considerations constrain utilization of
FGC wastes. In the future, how regulations encourage FGC waste
utilization will impact utilization substantially. Additional
focus of these considerations would be worthwhile.
Continuation of some of the ongoing programs and initiation at an
early date of some recently announced projects (such as EPA's character-
ization and monitoring of full scale FGC disposal sites and EPRI's
monitoring program at Conesville) are expected to substantially close
the data gaps associated with water and waste pollution from combustion
sources.
At the same time, new factors for the future are:
• major growth in FGC waste generation by utility plants, and
• additionally, increasing use of coal by industrial boilers
leading to FGC wastes from these sources.
4-2
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Increasing use of coal in industrial boilers will add new complications
to the problem of waste and water pollution control. These will princi-
pally be caused by the differences between large utility boilers and
industrial boilers in terms of:
a. type and quantity of wastes generated.
b. distribution of such waste generation points (i.e.,
location of boilers) including proximity to urban
areas. Industrial boilers will be smaller and more
numerous than large utility boilers.
Focus on waste management problems arising from such differences is
necessary.
4.2 Regulatory Considerations
Table S.2 lists federal legislation pertaining to:
• water effluents from power plants and/or
• the handling and disposal of FGC wastes in ponds,
landfills, coal mines, and the oceans.
The Toxic Substances Control Act (TSCA) may have minor impact on
utilization but it is not expected to be significant.
The principal regulatory considerations pertaining to water recycle/
treatment/reuse and FGC waste disposal/utilization are:
• Federal Water Pollution Control Act (FWPCA) of 1972
• Clean Water Act (CWA) of 1977
• Resource Conservation and Recovery Act (RCRA) of 1976
Federal Water Pollution Control Act (FWPCA)
The FWPCA established a program whereby all point source dis-
charges to navigable waters require a permit issued by the EPA
or a state delegated the authority by the EPA. The Act also
required industries to use the "best practicable" control tech-
nology currently available (BPCTCA) to control pollutant dis-
charges by July 1, 1977, and requires application of "best
available" technology economically achievable (BATEA). The
4-3
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Table S.2
Federal Regulatory Framework for Disposal
of FGC Wastes and Water Effluents
Possible Environmental
Impact
1.
4.
Surface Water
Contamination
Groundwater
Contamination
Waste Stability/
Consolidation
Fugitive Air
Emissions
Legislation
• Federal Water Pollution
Control Act Amendments
of 1972
• Clean Water Act of 1977
• Resource Conservation and
Recovery Act of 1976
• Resource Conservation
and Recovery Act of 1976
• Safe Drinking Water Act
of 1974
• Dam Safety \ct of 1972
• Surface Mining Control and
Reclamation Act of 1977
• Occupational Safety and
Health Act of 1970
• Federal Coal Mine Health
and Safety Act of 1969
• Clean Air Act and Amend-
ments of 1977
• Hazardous Materials
Transportation Act
of 1975
• Federal Coal Mine Health
and Safety'Act of 1969
• Occupational Safety and
Health Act of 1970
• Resource Conservation and
Recovery Act of 1976
Administrator
• Environmental
Protection
Agency (EPA)
• EPA
• EPA
• EPA
• EPA
• Army Corps of
Engineers
• Office of Surface
Mining Reclamation
and Enforcement
• Occupational Safety
and Health Adminis-
tration (OSHA)
• Mining Enforcement
Safety AdministratiOn
• EPA
• Department of
Transportation
• Mining Enforcement
Safety Administratto
• OSHA
• EPA
5. Contamination of
Marine Environment
• Marine Protection Research
and Sanctuaries Act of 1972
EPA
Note: Water effluents can only impact items 1 and 2
and only those apply.
4-4
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FWPCA Amendments of 1977 made the effective date for BATEA a
variable, depending on the chemical(s) being controlled. EPA
has established national effluent guidelines (based on BPCTCA
and BATEA) for existing power plants, as well as New Source
Performance Standards (NSPS) for plants for which construction
was initiated after the regulations were proposed. The dis-
charge limits for utilities are shown in Table S.3
Clean Water Act (CWA)
The Clean Water Act of 1977 (PL 92-217) incorporates the list
of priority pollutants (129 pollutants, including heavy metals)
into specific portions of PL 92-500. Section 301 of PL 92-500
now requires the EPA to set effluent limitations for each pol-
lutant based on BATEA. Point source dischargers other than
publicly-owned treatment works (POTW's) must comply with these
limitations by a specified future date. The date of compliance
depends on:
• type of pollutant.
• the level of treatment that is possible.
The priority pollutants were also included in Section 307 of
PL 92-217, which deals with "Toxic and Pretreatment Effluent
Standards." The limitations may be relaxed, in some cases, if
the POTW removes all or any part of the toxic pollutants.
These regulations will tighten treatment requirements for water
effluents but would also result in additional solid wastes con-
taining the pollutants. Regulatory requirements under the CWA
and RCRA may need to be synchronized.
Effluents guidelines, including best available technology eco-
nomically achievable (BATEA), new source performance standards
(NSPS), and pretreatment standards including the priority pol-
lutants under the Clean Water Act, are expected to be issued
later this year.
4-5
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Table S.3
Discharge Limits
1.2
for the Utility Industry
BPCTCA Limit
mg/1
BATEA Limit
mg/1
Limit for New Sources
Stream Pollutant
All Streams
pH (except once-through
Cooling
PCBs
Low-Volume Waste Streams
TSS
Oil and Grease
Bottom-ash Transport Water
TSS
Oil and Grease
Fly Ash Transport Water
ISS
Oil and Grease
Metal-Cleaning Wastes
TSS
Oil and Grease
Copper (total)
Iron (total)
Boiler Slowdown
TSS
Oil and Grease
Copper (total)
Iron (total
Once-Through Cooling Water
Free Available Chlorine
9
Cooling Tower Slowdown
Free Available Chlorine?
Zinc9
Chromium9
Phosphorus9
Other Corrosion Inhibitors
Material Storage Runoff8
TSS
PH
Max.'
Avg.
Max.'
Avg.
6.0-9.0
No Discharge
100 30
20 15
100 30
20 15
100 30
20 15
100 30
20 15
1 1
1 1
100 30
20 15
1 1
1 1
0.5 0.2
0.5 0.2
6.0-9.0
No Discharge
100
20
100,
20 3
100
20
100
20
1
1
100
20
1
1
0.5
0.5
1
0.2
5
30
15
30
15
30
15
30
15
1
1
30
15
1
1
0.2
0.2
1
0.2
5
Max.
Avg.
6.0-9.0
No Discharge
100 30
20 15
100; 30
206 15*
No Discharge
No Discharge
100
20
1
1
100
20
1
1
0.5
0.5
Limits Determined on a Case-by-Case Basis
50 50
6,0-9.0 6.0-9.0
30
15
1
30
15
1
1
0.2
0.2
50
6.0-9.0
Except where specifled otherwise, allowable discharge equals flow multiplied by concentration limitation.
Where waste streams from various sources are combined for treatment or discharge, quantities of each pollutan
attributable to each waste source shall not exceed the specified limitation for that source.
All sources must meet State Water Quality Standards by 1977 (Section 301 (b)(l)(c).
Maximum for any one day.
Average of daily values for 30 consecutive days.
Allowable discharge equals flow multiplied by concentration divided by 12.5.
Allowable discharge equals flow multiplied by concentration divided by 20.0.
Limits given are maximum and average concentrations. Neither free available chlorine nor total residual chlo
may be discharged iron any unit for more than 2 hr in one day, not more than one unit ot any plant may dischar *
free available of total residual chlorine at the sane time, unless the utility can demonstrate that the units ?*
a particular location cannot operate at or below this level of chlorlnation. ^ "*
D
Only runoff flow from material-storage piles associated with the reference 10-yr, 24-hr rainfall Is exempt
from these limitations.
9 Not applicable for BPCTCA, no detectable discharge from new sources.
Source: [1]
4-6
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Resource Conservation and Recovery Act (RCRA)
A major environmental concern associated with FGC
waste disposal is the potential contamination of groundwater.
The principal federal legislation which addresses these
potential problems is RCRA. Prior to enactment of the RCRA,
there was no comprehensive federal authority to regulate
disposal of solid wastes. This act is designed to eliminate
improper disposal of solid wastes by federally-regulated
disposal of hazardous waste and by state implementa-
tion of federal regulations (with federal assistance) of
disposal of non-hazardous solid waste. The Act defines
a hazardous waste as a waste which poses a "substantial
present or potential hazard to human health or the environment"
if improperly managed.
The regulatory philosophy in the RCRA for hazardous waste is
"cradle-to-grave" control. A manifest system will be used to
track the movement of hazardous waste from the point of generation
through transportation, treatment, storage, (often required if dis-
posal is off-site) and disposal. Detailed standards for hazardous
waste management facilities will be established by the EPA and per-
mits will be required. In addition, criteria and test methods to
identify hazardous wastes will be established; a list of wastes
known to meet the criteria will be included in the regulations.
Proposed regulations under the RCRA were issued on December 18,
1978, and are under review. The criteria for identifying
hazardous wastes include characteristics such as ignitability,
corrosiveness, reactivity (e.g., strong oxidizing agents),
and certain aspects of toxicity. The protocol for toxicity
(which is the most pertinent to FGC wastes) includes subjecting
the waste to an extraction procedure (EP), followed by chemical
tests for metals and pesticides.
Based on RCRA guidelines published in December 1978, the steps
to determine RCRA related requirements for FGC waste disposal are:
4-7
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a. The proposed Extraction Procedure (EP) specified in Sec-
tion 3001 protocol will be employed on each FGC waste to
determine if it passes or fails the protocol.
b. If a waste passes the tests, Federal criteria can apply
under Section 4004. Individual states are required to
adopt and enforce Section 4004 to regulate FGC waste dis-
posal, if they wish to receive federal financial assis-
tance under subtitle D of RCRA.
c. If an FGC waste fails the tests, it will be considered a
special case of hazardous wastes. Then waste analysis,
site-selection, security inspections, monitoring, closure,
and record-keeping standards of Section 3004 (hazardous
wastes disposal) will apply. Design standards under Sec-
tion 3004 as currently proposed are not required for FGC
waste disposal. This assures that the "special waste"
category will be retrieved for FGC wastes. Potentially,
these could undergo significant modifications prior to
scheduled promulgation in December 1979.
National Energy Act (NEA)
Aside from the regulations concerning FGC waste disposal, the
regulatory development that will impact the generation of FGC
wastes is the National Energy Act of 1978 (NEA).
At present, detailed regulations to implement the overall frame-
work of NEA are being worked out by the Department of Energy
(DOE). The regulations would promote the use of coal, renew-
able energy sources, and other alternative fuels over oil or
natural gas wherever possible. While the full impact of NEA
on utility and industrial power plants needs further definition,
the following appear to be indicated:
a. All new boilers, gas turbine and combined cycle units with
a capacity larger than 10 MWt will be prohibited from
using oil or natural gas unless specifically exempted by
DOE.
4-8
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b. Existing facilities that are coal capable but not using
coal now may be required to switch to coal or an alter-
native fuel. Financial capability to use coal or alter-
nate fuels will be condisered by DOE. DOE will consider
whether an existing boiler has furnace configuration and
tube spacing to burn coal. However, addition of partic-
ulates and FGD systems may not be considered substantial
modification preventing a switch to coal. Furthermore,
derating (i.e., decrease in capacity) of a boiler by an
amount less than 25% of nominal capacity by switching to
coal will not be considered substantial [57]. These reg-
ulations will apply to single units of 100 MMBtu/hr or of
multiple units in one site which is aggregate are by
design capable of a fuel input rate of 250 MMBtu/hr or
more.
Provisions exist for exempting certain powerplants from
restrictions against burning oil or gas if the owner can
demonstrate a certain degree of adverse cost effective-
ness from consideration of coal as an alternate fuel.
It is anticipated that NEA will encourage use of coal over the
next twenty years. Additional solid wastes and wastewater will
be generated by a switch to coal. Focus on these incremental
problems is essential.
Clean Air Act (CAA) — New Source Perforamnce Standards (NSPS)
New Source Performance Standards (NSPS) were issued by the EPA
in accordance with the Clean Air Act of 1970 for regulating
emissions of sulfur oxide, particulates, and nitrogen oxides
from large coal-fired steam boilers (>250 MMBtu/hr heat input)
commencing construction on or after August 1, 1971. These
NSPS, which are still in effect, are as follows:
• Sulfur oxides - 1.2 Ib (S02)/MMBtu heat input
• Particulate - 0.1 Ib/MMBtu heat input
• Nitrogen oxides - 0.7 Ib (NO_)/MMBtu heat input
4-9
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The Clean Air Act Amendments of 1977, provide for review of
existing air quality standards and revisions in emissions
regulations for new fossil-fuel-fired utility boilers. These
amendments require that new fossil-fuel-fired sources meet
both a standard of performance for emissions and an enforceable
requirement for specific percentage reduction of pollution for
untreated fuels, reflecting the degree of emissions reduction
achievable through the best system of continuous emissions
reduction regardless of the sulfur content of the fuel. In
accordance with these amendments, the EPA has proposed revised
NSPS for utility boilers based upon an evaluation of available
control technology. Comments on these revised standards are now
being reviewed and revised NSPS are expected in 1979.
In accordance with the Clean Air Act Amendments of 1977, the
EPA is also formulating NSPS for new industrial boilers.
The sizes to be covered by the revised NSPS may include boilers
q
as small as 10.5 x 10 joules/hr (10 MMBtu/hr) heat input. At
Q
present, all boilers under 263.7 x 10 joules/hr (250 MMBtu/hr)
fall under state and local regulations.
In addition to emissions limitations and S(>2 removal
requirements for new sources, the Clean Air Act Amend-
ments of 1977 include provisions for prevention of sig-
nificant deterioration (PSD) and review and revision of
regulations concerning nonattainment areas. PSD provisions
are roughly equivalent to those which have been enforced
over recent years by the EPA and therefore represent a
legislative endorsement of the EPA's administration and
enforcement regarding PSD. For nonattainment areas,
states must have revised state implementation plans
(SIP) for achieving primary air quality standards
(protective of human health). In both nonattainment
and nondegradation areas, permits are required for
construction of any major stationary source. As a
4-10
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minimum, conformance with NSPS will be required, but
more stringent restrictions may be imposed to meet air
quality standards.
Issues requiring further clarification concern the
impacts of NSPS, RCRA and NEA with respect to each other.
For instance NSPS regulations, if tightened, increase the
quantity of FGC wastes for disposal and hence the quantity
of wastes regulated. Similarly, RCRA related costs for
disposal may impact coal utilization.
4-11
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4.3 Water Recycle/Treatment/Reuse
The issue of water recycle/treatment/reuse in steam-electric power
plants is a complex one encompassing technology, environmental protection
aesthetics, and economics. Prior to the advent of national environmental
legislation, the magnitude and nature of water recycle/treatment/reuse
was determined principally by two factors: water supply availability and
economics. To provide a perspective on total water use in the utility
industry, Table S.4 presents data on a state-by-state basis of water uses
in thermoelectric power generation (including coal, oil, gas and nuclear
power).
The largest water usage in power plants is for cooling; hence, those
regions of limited water availability were the first to focus on recycle
systems such as cooling towers or ponds, whereas those regions with ample
water supplies often utilized once-through cooling. The installation of
water treatment systems prior to the advent of environmental regulations
was based principally upon operational economics, i.e., the necessity to
control the quality of the water going into the boiler, and so on, in
order to sustain operability, reduce maintenance, etc. The large population
centers and, concomitantly, the large electric users are predominantly
located in water-plentiful parts of the United States; hence, the usage of
water recycle/reuse systems was, until recently, limited.
With the passage of the Water Pollution Control Act Amendments of
1972 (PL 92-500) and other increasingly stringent environmental regula-
tions on industrial discharges and steadily increasing pressure on avail-
able water supplies, water recycle/treatment/reuse in power plants has
assumed increasing importance. All fossil-fired boilers require some
degree of water management including recycle/treatment/reuse. However, coal-
fired boilers require the broadest application of particulate and sulfur
control technology. Hence, coal-fired boilers present the most complex
water management issues. In view of the nation's commitment to increasing
coal utilization, water recycle/treatment/reuse at coal-fired power plants
has been the focus of many EPA sponsored studies.
4-12
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Table S-4
Water Used for Electric Utility Generation of Thermoelectric Power
in Million Gallons Per Day, By Regions, 1975
[Partiil figures may nut add to totals because of independent rounding)
Condenser and reactor cooling
Water Resources Council
region
New England * .
Mid-Atlantic
South Atlantic*Gulf
Grt*at t-aVgc
Ohio
Te nnc ssce
Upper Mississippi •
Suuris-Red-RaL'iy * -
\*u&otiri fia^in •
•
A*kais3$-\Vhitc*Rcd .
Texa^-Oulf .
Rio Grande . . .
Upper Colorado •
Lower Colorado •
Crest Oastn • . •
Pacific Not iJiwtif •
Calil*ornij * . • •
Alaska
Hawaii
Caribbean • *
I *nit£
-------
A.3.1 Effluent Streams
The quality and quantity of water required at various use points and
effluents generated depend on a number of factors including:
• Site location
• Ambient climatic condition
• Plant size and age
• Coal characteristics
• Plant design
• Operating philosophy
• Regulatory framework
Steam electric power plants (including coal-fired units) generate
two types of wastes:
1. Chemical wastes, usually as aqueous wastes. These depend
on fuel characterization, raw water quality, system design,
and others.
2. Waste heat dissipated to the environment via the cooling
water system.
These are separate subcategories under EPA Guidelines. This report focuses
on chemical wastes.
The major use points for water and, hence, generation points for
effluents in a coal-fired power plant are:
I. Continuous • Condenser cooling
• Steam generation
• Water treatment
• Ash handling
• Flue gas desulfurization
• Miscellaneous
II. Intermittent • Maintenance cleaning
• Drainage (including coal pile run-off)
4-14
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4.3.2 Water Management
Due to the multiplicity of uses of water in a coal-fired boiler and
the widely varying requirements for water quality in those uses, coal-
fired power plants present major opportunities for better management
through a combination of:
• Proper wastewater management to minimize net effluent
leaving the plant. For example, boiler blowdown is
often of higher purity than the original source of supply
and may be used as makeup to demineralizers.
• Combination of compatible wastewater streams with
appropriate equalization for either treatment or reuse
in some other use point in the power plant.
• Treatment of the appropriate streams for potential reuse
in the power plant itself or, if that is economically un-
justified, for discharge to a receiving stream. The
quality of recycle water required in its intended reuse
is the key element in determining the level of treatment
for reuse.
For illustrative purpose, the water use, effluent generation, and
potential for recycle around a 1,000 MW coal-fired unit are shown in
Figure S.2. In Volume 2 of this report, an assessment of each effluent
stream, including characterization and potential treatment methods for
reuse or discharge, is presented.
Increasing the amounts of water recycled or reused in any or all of
the wastewater streams is affected by the chemicals that enter either
through their occurrence in natural waters or through the operation of the
plant (for example, corrosion inhibitors, biocides, etc.). Hence, the
nature and type of treatment of water for recycle or reuse is determined
both by these factors and the regulatory limitations that may be placed
on discharges to the environment. Consequently, the water treatment tech-
nologies applicable to power plants attempting to achieve high recycle or
reuse rates are influenced principally by site-specific and system-specific
(design and operational) factors. In addition, the differences between
4-15
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— _ — CAS OR STEAM
CHEMICALS
OPTIONAL PATH
CONTINUOUS WASTES
INTERMITTENT WASTES
CHEMICALS
WATER1 FOR
MAINTENANCE CLEANING
TO STACK
FLUE GASES
BOILER TUBE
CLEANING,
FIRE-SIDE 6
AIR-PREKEATER
WASHINGS
WATER
FOR BACKWASH
19-60ms/d«r .
i 5000-16,000 GP3I
CHEMICALS
EVAPORATION
STEAM
GENERATING
BOILER
STEAM
400-COO m
(100,000-l90.000GPOt
FGO
SYSTEM
EVAPORATION
•- LOSSES
MAKE-OP
WATER
5-5.3
(•00-14001
HAW WATER
0.11-0. J2
130-89)
SLOWDOWN
1.5-2.5
1400-650)
MAKE-UP
WATER
1.5-2.5
1400-6501
—•-SLUDGE
WASTE WATER
0.4-2
(100-5001
1.9-2.8.10s
10.5-079 HO6!
ONCE-THROUGH
COOLING WATER
REORCULATING COOLING WATER
ft
, _1_J
DISCHARGE TO
WATER BODY
\ COOLING
40-52 \ TOW^a
nO,500-1S,800) \
EVAPORATION
ft DRIFT LOSS
EVAPORATION
LAB, SANITARY, &
MISC. OPERATIONS.
j AUXILIARY COOL'NG
SYSTEM OPERATIONS
HOO-SOOO mVdoy
10.3-1.6 K)«6PO>
WASTE WATER
nO-l90mV
-------
existing and new (or planned) power plants on economic water recycle are
many. In existing plants, piping and collection systems for wastewater
management and increased recycle or reuse can be a major expense item and
may potentially outweigh any other consideration.
For the reasons discussed above, economics of optimum water management
cannot be summarized generically. Details on a number of individual op-
tions permitting various levels of recycle/reuse are presented in Volume 2.
It appears that substantial opportunities exist for increased water
recycle/reuse by using existing technology. In fact, technology does exist
for almost complete if not total reuse of water and elimination of pol-
lutant discharges through effluents. In many cases, however, economic
constraints may be prohibitive, particularly in old and existing plants.
Economic considerations also raise two important factors:
1. Existing technology in many cases is from other industries
and in some cases on a smaller scale than required in the
utility industry.
2. The utility industry, being a regulated industry, has been
very reluctant to accept economic estimates on technology
unless such technology is demonstrated on a large scale
in this industry.
Increasingly stringent regulations and constraints on water avail-
ability will force further emphasis on water recycle/reuse. This will
be resisted principally on an economic basis since the installation and
operation of the technologies required to effect high degrees of recycle
or reuse will, in general, result in reduced overall plant efficiencies
and increased capital investments with no concomitant increase in the
generation of power. This situation will be exacerbated by the industry
reluctance to install systems which have not been widely demonstrated
and, furthermore, which require a degree of integration with the power
generation cycle which has not heretofore been necessary. Further in
some cases, industry is also questioning the cost/benefit aspect of water
recycle reuse. Consequently, an effective program of technology transfer
coupled with a judicious assessment of the techno-economic-environmental
4-17
-------
aspects of environmental regulations will be preeminent in determining the
rapidity and magnitude of water recycle and reuse in the steam-electric
power industry.
4.3.3 Data Gaps and Future Research Needs
The assessment in this report indicates that for optimum water
management additional information is necessary in the following areas:
• Ash handling, particularly environmental impact aspects
of dry ash handling.
• Chlorination and potential alternatives, particularly tech-
nical optimization and environmental impact assessment.
• Coal waste leachate and technical assessment of methods
to simulate leachates.
• Metal cleaning wastewater treatment (particularly chelated
complexes).
• Impact of chemical additives.
• Control methods for priority pollutants.
It should be noted that some of the ongoing EPA and EPRI projects
will provide information and go towards closing some of the above
data gaps.
Field scale demonstrations on some of the recently developed
technologies for some of the above may be desirable to encourage
broader acceptance of such technology for judicious water management
by utilities.
Furthermore, as stated earlier in this report, increasing use
of coal in industrial boilers is likely to add a new dimension to
existing water management problems in the future. Problems of water
and waste management at industrial boilers which tend to be small to
moderate in size (as compared with large utility boilers) are different
partly due to differences in control technology employed (for example,
use of sodium-based FGD systems) and differences in scale of operation.
Potential problems and their solutions in waste management for industrial
boilers need to be better defined.
4-18
-------
4.4 FGC Wastes Overview
As coal utilization continues to grow, the generation of FGC wastes
is expected to grow dramatically. Table S.5 provides an estimate on
anticipated growth in FGC wastes up to the year 2000.
Important aspects of the projected generation are:
• Fly ash collection will be principally accomplished
by electrostatic precipitation or bag filtration.
Dry handling is expected to increase in future.
• Flue gas desulfurization will continue to be dominated by
nonrecovery systems producing a throwaway waste.
More importantly, the vast majority of FGC wastes produced will
be disposed of, rather than utilized. Utilization is expected to grow
but at a lesser rate than the increase in the generation of FGC wastes.
In assuming FGC waste disposal practice, it may be noted that in
the past utilities operating FGC systems typically have disposed of
wastes by storage in ponds, often without provision for control of
overflows or seepage into groundwater. However, several factors will
dramatically influence disposal options in the coming years.
a. An increase in coal-fired capacity in the United States.
The total U.S. coal-fired electric utility generating
capacity was estimated at over 191,000 MW in 1976 [3] and
is expected to increase by 1986 to over 3^6,000 MW [4].
Use of coal in large industrial boilers (+25 MW equivalent
or larger) is likely to further increase the total coal-
fired capacity [5].
b. A major increase in the application of scrubber tech-
nology by utilities and a consequent increase in FGC
waste generation. At present over 16,000 MW of generating
capacity at some thirty plants utilize FGD systems. As
of September 1978, over 59,000 MW of capacity have been
committed [8]. Future increases are likely to be even
more dramatic.
4-19
-------
TABLE S.5
Projected Generation of Coal Ash and FGC Wastes
PROJECTED
*-
to
0
Coal Ash
Industrial
Utility
Total
FGD Wastes
Industrial
Utility
Total
1975 1985
10 Metric Tons % of Total 10 Metric Tons
8,590
64,440
52,060 - 73,030
1,090
21,050
6,200 - 22,140
% of Total
12
88
100
5
95
100
3 2000
10 Metric Tons
19,950
84,800
104,750
5,260
29,860
35,120
% of Total
19
81
100
15
85
100
Note: Estimates made prior to the National Energy Act of 1978.
Source: [5], [6], [7]
-------
c. Advances in stabilization technology for FGD wastes which
permit landfill disposal of partially dewatered solids
instead of ponding of difficult-to-handle wastes. In the
future, disposal of wastes in managed fills is likely to
be encouraged. In many cases this will require stabiliza-
tion prior to disposal.
d. Regulatory developments including the Clean Air Act of
1977 and the Resource Conservation & Recovery Act of 1976
(RCRA). Under the Clean Air Act of 1977, New Source
Performance Standards (NSPS) for criteria pollutants are
now under review by the EPA and may be significantly
tightened.
Against this background, characterization of FGC wastes and
environmental and economic impacts of disposal are increasingly
critical aspects of coal-fired boiler system design and operations.
4.5 Characterization of FGC Wastes
4.5.1 Chemical Characteristics
The important chemical characteristics of FGC wastes with respect
to the disposal operations may be classified under:
• Major components composition;
• Trace components composition; and
• Leaching potential and leachate composition.
These properties are important in assessing potential environmental
Impact of these solids.
Major Components
Variation in the major components in coal ash is principally
caused by the variability in the mineralogy of the coal. Table S.6
summarizes the ranges observed for coal ash obtained from different
coal ranks. Generally, more than 80% of the total weight of the ash
is made up of silicon, aluminum, iron and calcium compounds (presumably
oxides).
4-21
-------
Table S.6
Composition of Coal Ash According to Coal Rank3
Constituent Bituminous Subbituminous
Major Constituents
Silicon Dioxide, SiO
Aluminum Oxide, Al 0
Iron Oxide, Fe^
Calcium Oxide, CaO
Sodium Oxide, Na20
Magnesium Oxide, MgO
Minor Constituents
Titanium Oxide, Ti02
Sulfur Oxide, S03
Potassium Oxide, KO
Phosphorous Pentoxide,
7-68
4-39
2-44
1-36
-------
Among the important factors that affect the composition of FGC
wastes are the composition of the coal, boiler type and operating con-
ditions, particulate control method, and the FGD system type and operating
conditions. The principal substances making up the solid phase of FGC
wastes are given in Table S.7. The calcium sulfate (hemi- or dihydrate)
content depends principally on the extent of oxidation in the FGD system.
Higher sulfate content is usually observed in systems burning low sulfur
western coals and in forced oxidation systems. The waste can also
contain a variable amount of fly ash which arises from admixing or if the
FGD unit is also used as a particulate control device. Various amounts
of unreacted raw materials (e.g., limestone) also can be present depending
on the quality and utilization of these materials.
A significant number of generic and proprietary processes have been
proposed whereby chemical and physical properties of FGC waste would be
modified leading to "stabilization" of the waste. Two of these (those
developed by IU Conversion System and Dravo) are now offered commercially
for treating FGC wastes from utilities. Data are available on the effects
of stabilization on strength and permeability properties of FGC wastes;
however, only limited data are available on complete chemical characteriza-
tion of the stabilized materials.
A number of dry sorbent processes are now under study and it is
expected that some will be in commercial practice by 1981. Very limited
data are available on the characteristics of these wastes produced by
the processes.
FGC waste solids may carry with them occluded liquors which may
contain a variety of dissolved substances. The major components of the
liquor (species which can be present at concentrations of 100 ppm or more)
include calcium, chloride, fluoride, magnesium, potassium, sodium, sulfate
and sulfite with total dissolved solid levels ranging between 2,500-100,000
ppm. Table S.10 summarizes some typical concentration ranges. The con-
centrations of calcium, sulfate and sulfite are generally limited by the
solubility products of the respective salts and the ion activities which
depend on ionic strength. Thus, variability in systems and operations
affect these levels.
4-23
-------
Table S.7
Major Components in FGC Waste Solids
Process
Limestone
Shawnee
Cholla
Moj ave
LaCygne
Lawrence
Lime
Shawnee
Phillips
Paddy's Run
Forced Oxidation
Shawnee (lime)
Shawnee (limestone)
Black Dog (limestone)
Dual Alkali
Parma
Scholz
Gadsby
Fly Ash
Cols trip
Milton R. Young
CaSQ3-l/2H20
Composition (Percent by Weight)
,. ~a
CaCO,
Fly Ash Other
19-23
11
2
20
:i-7
50
13
94
3
3
8
2-10
11
<1
—
7
1
9
40-70 5-30%MgSO
i
60
Generally X=l/2 for high sulfite solids and x=2 for low sulfite solids
Unknown soluble salt
Source: [10-21]
4-24
-------
Minor and Trace Constituents
The major source of minor and trace species present in coal ash is
coal which contains a large number of trace elements occluded in the
mineral matrix or as organometallic compounds. Typical ranges of minor
and trace species in coal ash are shown in Table S.8. A great many
trace species have been detected and over a wide concentration range in
various coal ash samples. A few elements originally present in the coal
(notably sulfur, chlorine and mercury) are nearly completely volatilized
and leave the boiler as gaseous products. Condensation of more volatile
species on the surface of fly ash particles may result in a higher con-
centration of these species on the smaller fly ash particles. This en-
richment has been observed, for example, for arsenic, antimony, selenium
and lead.
The type and concentration of trace species in FGC wastes depend
primarily on the amount of ash collected or mixed with the waste, the
efficiency of the scrubber in capturing volatile trace constituents and
the trace species content of any FGD additive. Typical data on the
range of trace species in FGC wastes are given in Table S.9 and represent
data on the sum of the content of the liquor and solid waste. There are
little available data on the distribution of these trace species between
the two phases. The presence of highly volatile species such as arsenic,
mercury and selenium will depend to a large extent on the efficiency with
which these are captured by the scrubber. In addition, the ash present
in the inlet to the scrubber may contain adsorbed compounds of these
elements and add to the total in the FGD wastes. However, for most of
the available data on the trace species content of FGC wastes, there
appears to be no direct correlation with the trace species content of
the coal burned. This may not be surprising in view of the fact that the
FGC waste solids which have been obtained came from units which do collect
varying amounts of the fly ash produced; and in addition, some highly
volatile species may not be collected in the scrubber.
The range of trace elements observed for FGC waste liquors is given
in Table S.10. A small fraction of the total trace species present in
4-25
-------
Table S.8
a
Range of Minor and Trace Species Present in Coal Ash
Concentration Species Range (ppm)
Category
101 - 104 ppm
2
1-10
As
B
Ba
Cu
F
Mn
Mo
P
Pb
Sn
Sr
V
Zn
Zr
Ag
Be
Ce
Cl
Co
Cr
Ga
Ge
Hg
La
Li
Nb
Ni
Sb
2-1000
15-6,000
50-13,900
20-3,000
16-1,000
31-10,000
5-1,500
5-10,000
10-1,500
10-4,250
40-9,600
10-1,000
25-15,000
100-1,450
1-50
1-200
< 53-250
41-270
5-440
5-500
10-135
20-285
0.01-100
19-270
48-500
21-78
15-610
< 2-200
4-26
-------
Table S .8 (continued)
Range of Trace Species Present in Coal Ash'
Concentration
Category
Species
.Range (ppm)
<2
Sc 2-155
Se 1-50
Th 21-54
W 7-30
Y 21-460
Yb 2-23
Au, Bi, Br, Cd,
Hf, I, Ir, Lu,
Pd, Re, Ru, Os,
Rh, Rt, W
<2
Most of the data were derived from coals ashed at 600°C
(1140°F) using atomic absorption spectroscopy
Source: [22,23,24]
4-27
-------
Table S.9
Total Concentrations of Trace Constituents in FGC Waste and Coal
Species FGC Waste Coal
Solids (pptn) (ppm)
Arsenic 0.6 - 63 3-60
Beryllium 0.05 - 11 0.08 - 20
Cadmium 0.08 - 350
Chromium 3 - 250 2.5 - 100
Copper 1-76 1 - 100
Lead 0.2 - 21 3-35
Manganese 11 - 120 -
Mercury 0.001 - 6 0.01-30
Nickel 6-27
Selenium <0.2 - 19 0.5-30
Zinc 10-430 0.9 - 600
Source: [25,26]
4-28
-------
Table S.10
Typical Concentration Ranges of Chemical Species
In FGC Waste Liquors and Elutriates
pH (PH units)
TDS (ppm)
Major Constituents (ppm)
Calcium
Chloride
Magnesium
Potassium
Sodium
Sulfate
Fluoride
Trace Constituents (ppm)
Antimony
Arsenic
Beryllium
Boron
Cadmium
Chromium
Cobalt
Copper
Iron
Lead
Manganese
Mercury
Nickel
Selenium
Zinc
Eastern Coal FGC Wastes
(3-20 Observations)
7.1 - 12.8
2,500 - 150,000a
<100 - 2,600
400 - 5,600
0.1 - 3,400
11 - 760
36 - 50,000a+
720 - 50,000a+
<1 - 770
Western Coal FGC Wastes
(3-10 Observation)
2.8 - 10.2
5,000 - 95,000
240 - 45,000
25 - 43,000b
1,650 - 9,000
2,100 - 19,000
0.7 - 3.0
0.46 -
<0.004 -
<0.0005 -
18 -
0.004 -
0.001 -
<0.002 -
0.002 -
0.02 -
0.0002 -
<0.01 -
0.00006 -
0.03 -
0.003 -
<0.001 -
1.6
1.8
0.05
76
0.1
0.5
0.1
0.4
0.1
0.55
9.0
0.07
0.91
2.7
27
0.09 -
<0.004 -
0.0006 -
8 -
0.011 -
0.024 -
0.05 -
0.002 -
0.11 -
0.0014 -
0.007 -
<0.01 -
0.005 -
<0.001 -
0.028 -
0.22
0.2
0.14
140
0.044
0.4
0.17
0.6
8.1
0.37
2.5
0.07
1.5
2.2
0.88
Levels of soluble sodium salts in dual alkali waste (filter cake) depend strongly
on the degree of cake wash. The highest levels shown reflect simple measurements
on an unwashed dual alkali filter cake (see next in Volume 3).
Levels of soluble chloride components in wastes are dependent upon the chloride-
to-sulfur ratio in the coal. The highest levels shown are single measurements
for a western limestone scrubbing system operating in a closed-loop using cooling
tower blowdown for process makeup water.
Source: [26,27]
4-29
-------
FGC wastes Is found dissolved in the waste liquor; the major portion is
found in the solid phase. No direct generalized correlation exists
between trace species level in the parent coal and the waste liquors.
These two factors suggest that some of the levels are limited by the low
solubilities of the trace metal hydroxides, oxides, or carbonates.
Leaching Potential and Leachate Composition
The potential for groundwater and surface water contamination from
FGC waste disposal varies with waste characteristics, method of disposal,
and site conditions. This contamination may occur by release of occluded
waste liquors and/or leachings of FGC waste species. Leaching may involve
surface leachings usually limited by waste dissolution and diffusion and/
or flow-through waste pores. For either mechanism to occur, the waste
must be nearly or fully locally saturated with moisture. The species
that are dissolved in the waste liquor are more readily available than
those in the solid phase. The initial leachate composition in a first
flush mechanism will be roughly equivalent to composition to the occluded
liquor. Subsequent pore volumes would contain levels which would be de-
termined to a greater extent by the amount of solid waste dissolution.
This has been shown experimentally with first pore volume displacement
(PVD) data approximating those of interstitial liquor and successive dis-
placements showing rapidly decreasing levels of total dissolved solids
and certain highly soluble species (e.g., sodium, chloride). Pore volume
refers to the interstitial space in a mass of FGC solid particles not
occupied by the solids themselves. If liquors are present, they occupy
this space. Initial concentrations of trace elements tend to be low
generally although some have been noted to exceed drinking water stan-
dards. Successive PVD's (i.e., pore volume displacements) usually contain
decreasing concentrations of most trace species. The concentrations of
some trace species (e.g., arsenic and zinc) have been observed to remain
relatively constant. Concentrations of calcium and sulfate have also been
observed to level off based on the gypsum solubility product.
4-30
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4.5.2 Physical Properties
Disposal of FGC wastes involves handling and transport, placement
at a disposal site, potential reuse, and assessment of environmental
impacts are key factors in ensuring reasonable disposal practices. Many
physical properties of FGC wastes affect the manner in which they are
carried through the disposal process and hence influence impacts. Re-
lationships of waste consistency versus solids content (for example,
Atterburg limits), viscosity, compaction characteristics, and particle
size are important in determining handling methodology. Strength and
compressibility properties yield data on both placement and filling
conditions at the disposal site. Properties such as permeability may
govern the quantity and quality of leachate and thus determine the extent
of groundwater pollution. A listing of the range of values observed for
physical and engineering properties of fly ash and FGC wastes is given
in Tables S.ll and S.12.
The specific gravity of fly ash generally increases with its iron
oxide content [33]. The specific gravity of ash-free sulfite wastes is
higher than that of ash-free sulfate wastes. (See Table S.12).
Both fly ash and other FGC wastes have a generally very uniform particle
size distribution. As much as 70% by weight of a fly ash sample may
consist of hollow spheres.
FGC wastes exhibit little or no plasticity (they convert from a semi-
solid to a viscous slurry over a narrow moisture content) and are similar
to silts and sandy silts.
The viscosity of fly ash is generally lower than other materials
of similar grain size at equal solids content. Results of pumping tests
on FGC wastes indicate that some of these wastes may be pumped at 60%
solids content and that addition of fly ash increases the fluidity of
the waste.
4-31
-------
Table S.ll
Physical and Engineering Properties of Fly Ash
Property
a
Grain Properties
Specific Gravity
Grain Size
Coefficient of Uniformity
Atterburg Limits
Range of Values
1.97 - 2.85
88 - 93% in the 2-74ym range
1.2 - 1.4
not plastic
Compaction Properties
Bulk Dry Density
Field Density
Controlled Compacted Density
Optimum Moisture Content
Maximum Proctor Dry Density
Permeability
0.96 gm/cc (average)
1.12 gm/cc (average)
Up to 1.65 gm/cc
16 - 31%
1.14 - 1.65 gm/cc
-4
0.5 - 5 x 10 cm/sec
Strength Parameters
Angle of Internal Friction
28° - 38° (at densities of 0.8
to 1.2 g/cc)
Source: [28, 29, 30]
'Source: [31, 32-34, 35, 36]
:Source: [32, 35, 36]
Source: [32]
4-32
-------
Table S.12
Physical and Engineering Properties of FGD Wastes
Property
Range of Values
Grain Properties
Specific Gravity
Grain Size
Coefficient of Uniformity
Atterburg Limits
Sulfite Rich
2.49 - 2.86
85-93% in the
2-74ym
4-10/i >74um
1.3 - 1.5
Little or no
Plasticity
Sulfate-Rich
2.34 - 2.35
66-76% in the
2-74ym
18-30% >74um
2.3 - 2.5
Little or no
Plasticity
Compaction Properties
Maximum Dry Density
Optimum Moisture Content
Compressibility
1.15 - 1.36 gm/cc
35-52%
Up to 10% of Original
height
1.26 - 1.52 gm/cc
13-33%
Much less than 10%
of Original Height
Permeability
Strength Parameters
Angle of Internal
Friction
Effective Cohesion
(0.9 - 4) x 10
(unstabilised)
-5
(0.005 - 14)
(stabilized)
x 10
-5
30-36° (unstabilized)
M) (unstabilized)
(1 - 98) x 10
(unstabilized)
-5
up to 42° (unstabilized)
»\X) (unstabilized)
Source:[33,37,38,39,40,41,42,43]
'Source:[44, 45, 46]
:Source:[16,26,40,47,48]
Source .-[33,40,47]
4-33
-------
The compressibility of fly ash near its maximum dry density is low.
Since the density of fly ash is lower than compacted natural soils, it
may cause less settlement when placed over subsoils of equal fill
stiffness.
The compaction behavior of sulfate and sulfite FGC wastes is sig-
nificantly affected by the particle morphology, grain size distribution
and specific gravity of the material. Generally, addition of fly ash to
sulfate- and sulfite-rich wastes increases their maximum dry density and
decreases their moisture content at the maximum dry density. Repeated
impacts on sulfite-rich wastes appear to cause progressive breakdown of
the waste particles. Sulfate wastes are generally less compressible
than sulfite wastes due in part to different particle morphology. Con-
solidation tests indicate that uncompacted sulfite-rich FGD wastes may
compress as much as 10% of their original height in a fill while sulfate-
rich wastes are much less compressible.
The shear strength of freshly placed fly ash depends primarily on
its dry density. Aged fly ash may exhibit greater strength due to greater
cohesion produced by pozzolanic cementation. Angles of internal friction
may increase to 43° and cohesion to more than 100 psi.
FGD wastes generally exhibit insignificant effective cohesion but
unconfined compression strength in the 10-20 psi range is obtained for
samples at their maximum dry density. Strength parameters for stabilized
wastes are sensitive to moisture content and age of the waste. Addition
of stabilizing agents such as fly ash and lime causes great increases in
strength for the cured materials.
Fly ash is a freely draining material. The permeability of sulfite-
rich wastes is generally lower than that of sulfate-rich wastes, although
well-managed gypsum formation in a dual alkali plant may produce low
permeability waste. Addition of stabilizing agents may decrease permea-
bility by one or more orders of magnitude. A decrease in permeability
is also observed with an increase in fly ash content due to a decrease
in the void ratio (or increase in solids content).
4-34
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4.5.3 Research Needs in Characterization
Major data gaps exist in the characterization of coal ash and FGD
wastes with respect to:
• Data from field scale operations. There is an important
need to characterize both stabilized and unstabilized
wastes in terms of their behavior in the actual field
disposal operation.
• Data on leaching behavior and leachate characteristics
which will lead to better methods of assessing environ-
mental impacts.
• Characterization of dry sorbent FGC process wastes and
environmental impacts associated with their disposal.
• Data on trace species migration from ash/FGD waste co-
disposal and from stabilized FGC waste disposal into
the surrounding environment.
• Data on variation of waste properties (physical and
chemical) with various stabilization processes.
• Data on speciation of trace contaminant, both inorganic
and organic. Speciation refers to the actual chemical
compounds of the trace contaminants. While analytical
methods usually indicate the concentration of such trace
contaminants, the nature of the compounds in which the
trace contaminant occurs (i.e., speciation) is usually
unknown.
4.6 FGC Waste Disposal
4.6.1 Impact Issues
The environmental impact issues requiring consideration in handling
and disposal of FGC wastes are:
a Air-related. These include fugitive particulate emissions,
emissions <
compounds;
emissions of S02 and H_S and emissions of trace metal
4-35
-------
• Water-related. These include groundwater contamination,
surface water point source discharges and runoff;
• Land-related. These include physical stability (subsidence,
liquefaction or other structural failure, erosion, etc.) and
land use considerations; and
• Biological impacts both in the site and adjacent areas.
Potential impact issues are highly site- and system-specific. With
that understanding, the major types of impact issues associated with
various disposal options will be discussed below. The range of waste
types and possible disposal conditions is sufficiently broad to elimi-
nate the potential for "generally significant" issues to be associated
with any of the disposal options. Further, site-specific application
of appropriate control technology can be employed to mitigate adverse
impacts. In other words, issues of potential significance in FGC waste
disposal can best be defined in terms of specific waste types, disposal
practices, and disposal environments. The significance of many potential
impact issues may be better quantified by additional field-scale operating
experience (and environmental monitoring) with FGC waste disposal. This
is particularly desirable for defining potential issues in the categories
of water quality and biological impacts.
A.6.2 Disposal Options and Potential Impacts
A number of methods are potentially available for the disposal of
FGD wastes either on land or in the ocean. Applicability of disposal
options for FGD wastes can be broadly categorized on the basis of the
nature of the wastes and the type of disposal.
Table S.13 lists potential disposal options for the various types of
wastes. In this table sulfur is included as a potential waste product;
however, it is more likely that sulfur as a final product from recovery
FGD systems will be produced for utilization. More importantly, recovery
FGD processes are likely to require prescrubber systems to remove particu-
lates, chlorides, and other flue gas constituents which might contami-
nate absorbent liquors. Prescrubber blowdown from these systems will
4-36
-------
Table S.13
Potential Disposal Options
Land Disposal
Wet Pond (Conventional)
Gypsum Stacking
Dry Impoundment
Surface Mine
Underground Mine
Ash FGD Waste Codisposal Sulfur
C
P
C
C
P
C
P
P
C
C
P
P
P
P
Ocean Disposal
Shallow - Outfall
Concentrated (con-
vent, ional) Dump
Dispersed Dump
Reef Construction
(Stabilized)
Deep - Concentrated (con-
ventional) Dump
Dispersed Dump
P
P
P
P
P
P
P
P
P
P
P
P
C - commercial practice
P - reasonable potential
Source: Arthur D. Little, Inc.
4-37
-------
result in wastes analogous to the wastes from nonrecovery FGD systems
(although In smaller quantities). Hence, in the future if recovery pro
cesses are used, it will thus reduce, not eliminate, FGD wastes.
At present, all FGC wastes are disposed of on land. To provide a
perspective, Table S.14 summarizes data on present disposal practices
on utility FGC systems. In addition to the commercially operating units,
a number of FGC disposal systems are in operation for testing, develop-
ment and/or data gathering purposes. A list of such current field test-
ing programs on FGC wastes and associated data on the systems involved
is presented in Table S.15.
A brief review of land disposal methods and potential ocean disposal
options is presented below.
4.6.2.1 Land Disposal
The principal methods of land disposal .°re:
• Wet ponding;
• Dry impoundment; and
• Mine disposal.
Wet Ponding; This method is at present more widely used than
any other. Ponding can be employed for a wide variety of FGD
wastes including unstabilized materials; however, ponding has
been employed with the Dravo stabilization process. Ponds can
be designed based on diking or excavation and can even be engi-
neered on slopes. But the construction of dikes or other
means of containment for ponds is usually expensive. In the
future, particularly if stabilization of FGD wastes is widely
practiced, ponding will probably be limited to those sites that
can be converted to a pond with minimal construction of dams
or dikes. A special case of wet ponding is gypsum stacking now
4-38
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Table S.14
Present Disposal Practices
Utility FGC Systems
(No. Plants/Total Capacity in Mw)
Western
Eastern
i
U)
VO
Waste
FGD Only
Co-disposal
Stabilized
Totals
Dry Fill Wet Pond
1/200
8/4135 13/6705
8/4135
14/6905
Dry Fill Wet Pond
2/365
2/245 6/1965
6/2615 1/1650
8/2860
9/3980
Source: Arthur D. Little, Inc.
-------
Table S.15
Summary of Current Field Testing Programs for FGC Waste Disposal
(Status as of March 1979
•c-
o
Location/Utility (Plant)
Land Disposal
Pilot/Prototype
TVA (Shawnee)
Louisville Gas & Electric (Paddy's
Run)
Gulf Power (Scholz)
Gulf Power (Scholz)
(Not applicable)
Sponsors
Principal
Contractors'
Scjrubber System
EPA(IERL)/TVA Bechtel/TVA
EPA/IERL LGE/CE/UL
EPA(IERL)/EPRI CEA/ADL
EPRI CIC/Radian/Ardaman
EPRI
Full Scale
Columbus & Southern Ohio (Conesville)EPRI(IERL)
Louisville Gas & Electric (Cane Run) EPA(IERL)
Minnesota Power (M.R.Young) EPA(IERL)
(Monitoring 3 Disposal Areas) EPA(IERL)
(Multiple Site Monitoring) EPA(IERL)
(Unspecified)
Ocean Disposal
Pilot/Prototype
Columbus & Southern Ohio (Conesville) DOE/EPA(IERL)/ SUNY/IUCS/NYSERDA
(Not Applicable) EPA(IERL) NEA/ADL
MB/Batelle
LGE/Bechtel
UND/ADL
WES
Not selected yet
MB
Conventional Lime
Conventional Limestone
Forced Oxidation
Conventional Lime (Carbide)
Dual Alkali (Limestone
Limestone Forced Oxidation
Conventional Lime (Thiosorbic)
Dual Alkali (Lime)
Alkaline Ash
Conventional Lime & Limestone
Many
Conventional Lime
Conventional Lime (Thiosorbic)
MANY
AM. - Arthur D. Little
CE - Cmabuatlon EnRlnperlnR
CEA - Combustion Equipment Asuorlates
CIC - Chlyoda International
DOE - Department of F.nerRy
EPA - U.S. Environmental Protection Aitenry
EPRI - Ftertrlr Power Rocenrrh Institute
ntrr, - ii' onvf-minn
l.cr - Loulivlllf* f.m ami Flortrlc
ml - Mlrh.vl B.lkrr, Jr.. [nr.
NTA - N-u lni'l.iml Aqinrhim
ffYSHRDA - New Vork ^t.Tlr Cn'Trv Reaenrrh fc Development Authority
PASNY - Pover Authority of the State of**"
SWY - Stnlo (inlverfitty of Ni-w York
TVA - Tennessee Vullev Authority
UL - University of l.nulnvllle
IIND - University of North Dnkota
WFS - Armv Corps of Knglneers
(W.iterw.iv 4 Experiment Station)
-------
Table S.15(Continued)
Summary of Current Field Testing Programf for FGC Waste Disposal
Waste Characteristics
Type Form
Disposal
Mode
Program
Status
.p-
i
Sulfite-Rich
Gypsum
Sulfite Rich
Sulfite Rich
Gypsum
Wet & Dry Impoundment
Dry Impoundment
Filter Cake (Stab &Unstab)Dry Impoundment
Many
Filter Cake (Unstab)
Filter Cake (Stab & Unstab)Dry Impoundment
Thickened Slurry (Unstab) Stacking
- Liner Study
Underway
Underway
Underway
Planned
Underway
Planned
Sulfite-Rich
Sulfite-Rich
Sulfite-Rich
Unspecified
Many
Sulfite-Rich
Filter Cake (Stab) Dry Impoundment
Filter Cake (Stab) Dry Impoundment
Filter Cake (Unstab) Surface Mine
Ash & FGD Waste Slurries Wet Ponds (unlined)
Many
Slurry (Stabilized)
Many
Underground Mine
Planned
Planned
Underway
Underway
Planned
Proposed
Sulfite-Rich
Many
Filter Cake (Stab)
Many
Reef Construction
Conventional Dump
Underway
Underway
-------
under evaluation. In this case, if the operation were analo-
gous to that for phos-gypsum, gypsum slurry (typically from
forced oxidation systems) would be piped to a pond and allowed
to settle and the supernate recycled. Periodically the gypsum
would be dredged and stacked around the embankments, thus build-
ing up the embankment.
Leaching from wet ponds is likely to be an important environ-
mental issue that must be addressed in pond design and opera-
tion. Recent R&D efforts on wet ponding have centered on:
• Effective means of containing pollutants within the
disposal area; i.e., study of potential liner material.
• Better definition of leaching mechanism from lined and
unlined ponds.
Dry Impoundment Methods; These may include any of the following
variations:
• Land disposal of dry ash.
• Interim ponding followed by dewatering and sometimes
excavation and landfilling;
• Mechanical dewatering and landfilling of FGD wastes;
• Blending with fly ash and landfilling of FGD wastes; and
• Stabilization through the use of additives (non-proprietary
or otherwise).
Typically, for dry impoundment type of disposal, the wastes,
if necessary, are thickened and dewatered to a high solids
content and blended with fly ash and lime or other additives
like cement, Calcilox® etc., thus forming a material with
cementitious properties. This material is transported to
the disposal site where it is spread on the ground in
4-42
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0.3 to 0.9 meters (1 to 3 foot) lifts and compacted by wide
track dozers, heavy rollers or other equipment. Layering
proceeds In 0.3 to 0.9 meters (1 to 3 foot) lifts in segments
of the site. The ultimate height of a disposal fill is site-
specific but may be 9 meters (30 feet) to as high as 25 meters
(^80 feet) or more. A properly designed and operated dry
impoundment system can enhance the value of the disposal site
after termination or at least permit post operational use.
Mine Disposal; A disposal method that is receiving increased
attention is mine disposal. It appears that surface coal mines
and underground room and pillar mines for coal, limestone, or
lead/zinc ores offer particular potential. Of the four cate-
gories of mines noted above, coal mines, and in particular
surface area-type coal mines, are the most likely candidates
for waste disposal. Coal mines offer the greatest capacity
for disposal, and they are frequently tied directly to power
plants. In fact, many new coal-fired power plants are "mine-
mouth" (located adjacent to the mine or within a few miles of
it) and the mine provides a dedicated coal supply. Since the
quantity (volume) of FGC wastes produced is considerably less
than the amount of coal burned, such mines usually would have
the capacity for disposal throughout the life of the power
plant. The space available in surface mines for FGC waste
disposal is also a function of the overburden and swell ratio
and strictures on final contouring.
In general, inactive surface mines are considerably less promising
than active mines for FGD waste disposal. Unreclaimed surface
mines can be used for disposal of wastes between remaining spoil
banks, and these may offer suitable sites for disposal. However,
because of recent surface mine reclamation and other legislation,
the number of sites and total capacity available for wastes in the
future will be limited.
4-43
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In active surface mines, there are basically three options for
the placement of FGD wastes:
• In the working pit, following coal extraction and prior
to return of overburden;
• In the spoil banks, after return of overburden but prior
to reclamation; and
• Mixed with or sandwiched between layers of replaced over-
burden.
At present there are only two commercial operations involving
mine disposal of FGD wastes in surface coal mines—one at Texas
Utilities' Martin Lake Station and the other at Square Butte's
Milton R. Young Station (North Dakota). Both stations fire lig-
nite and the disposal involves returning combined fly ash and
calcium-sulfur solids from S0~ removal to the respective mines.
The operation at the Baukol-Noonan mine which supplies coal to
the Milton R. Young Power Station is an EPA mine disposal demon-
stration project. At this time both pit-bottom and spoil bank
disposal are being employed. Mine disposal of FGD wastes can
potentially be employed for subsidence control, acid mine drain-
age neutralization, reclamation of mine areas or as soil amend-
ments for tailings disposal from mining operation. Thus, there
could be subsidiary benefits from this type of disposal.
4.6.2.2 Ocean Disposal
Ocean disposal of FGD wastes is not practiced in the United States
today. However, if it could be practiced under environmentally acceptable
conditions, it could represent an important option, particularly in Fed-
eral Regions 1 and 2 (the Northeast) where land for disposal is limited.
For this and other reasons, EPA has been studying the disposal of FGD
wastes in the ocean. Ocean disposal may be considered in the shallow
ocean (i.e., on the continental shelf) or deep ocean (off shelf). Each
of these has a different ecosystem with a different set of potential
impacts. At present a number of viable techniques exist for transporting
FGC wastes to offshore disposal sites.
4-44
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At present, regulation of dispersed ocean dumping of stabilized and
unstabilized FGD waste falls under the Marine Protection Research and
Sanctuaries Act and is administered by the Environmental Protection Agency.
The dumping would be required to be limited to an EPA-prescribed dumpsite
under the specified disposal criteria.
• Trace contaminant (e.g., Hg, Cd) content of the dumped
materials would be no higher than 50% above that of
background sediments at the dumpsite;
• Concentrations of the dumped material in the water
column four hours after release would not exceed 1%
of the 96-hour LC^Q of the material to local sensitive
species; and
• No feasible alternatives to ocean disposal are available.
Stabilized, brick-like FGC waste may be used to create artificial
fishing reefs with EPA concurrence. Artificial fishing reefs are not
subject to the Ocean Disposal Criteria but FGC waste disposal may be
a special case. While ocean disposal of FGC sludges is an option that
may be available to throwaway system users with economic access to
the ocean, new ocean disposal initiatives are now discouraged by the
regulatory agencies. At present, two studies under EPA sponsorship
or participation involve the ocean disposal of FGC wastes.
4.6.3 Potential Impacts
Potential impacts are determined by:
• Characteristics of wastes
• Mode of disposal
• Characteristics of the site.
Potential impacts that should be considered in planning a disposal opera-
tion are summarized in Table S.16. Proper application of site specific
control technology as discussed in Sec. 4.6.4 can mitigate against adverse
impacts.
4-45
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Table S.16
Disposal Options Vs Impact Issues
Impact Issues
Disposal Mode
Wet Ponding
Dry Impoundment
Mine - Surface
- Underground
Ocean - Shallow
- Deep
Land Use
X
X
Water
Surface
X
X
X
X
X
Quality
Groundwater
X
X
X
X
Air Quality
Fugitive Gaseous Biota
X
X XX
X XX
X X
X
X
Source: Arthur D. Little, Inc.
-------
4.6.4 Impact Control Measures
It is expected that much of the difference between potential and
actual impacts for the FGC waste disposal options discussed above will
be determined by the degree to which presently available control technology
becomes incorporated as "good design" and "good practice" in typical dis-
posal operations. Good design and practice could also minimize the
potential for adverse impact from abnormal events. Important considera-
tions in the application of present control technology are briefly discussed
below:
a. Site Selection; Site selection may or may not be considered
control technology. However, there is no question that proper
site selection could help ameliorate or even eliminate most
of the potential disposal impacts discussed above. Specifically,
the following mitigative combinations of site characteristics
and impact issue categories are considered applicable:
Potential Impact Issue
Land Use
Water Quality
Air Quality
Mitigative Site Characteristics
Proper topography, geology and
hydrology; absence of nearby
conflicting land uses.
As above for land use, plus
absence of nearby sensitive
receiving waters (surface or
aquifers). For example, a small
stream or very pure aquifer may
impose greater constraints than
a relatively large stream or
impure aquifer.
Absence of "non-attainment area"
and Class I Prevention of Signif-
icant Deterioration designations
for total suspended particulates.
Usually this is even more important
for the Power Plant Siting.
4-47
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Biological Effects Absence of sensitive biological
resources.
Control Options; Process operations to ameliorate environmental
impacts of FGC waste disposal are:
1. Dewatering; As discussed earlier, dewatering of FGC
waste prior to processing or land disposal can result
in major improvements in physical stability and reduce
water quality impacts regardless of which disposal
approach is employed, including those discussed below.
2. Stabilization; Stabilization appears to be highly
relevant to the mitigation of land use issues, in-
cluding the potential for abnormal events (i.e.,
disposal area liquefaction or other catastrophic
failure modes), and the suitability of disposal sites
for a broader range of post closure uses requiring
increased bearing strength. Stabilization techniques
resulting in decreased waste permeability and elimina-
tion or reduction of hydraulic load can be considered
mitigative of potential water quality impacts due to
leachate migration. This factor should be considered
in balance with the requirements for disposal area
runoff on a site-specific basis.
Stabilization reduces permeability and hence reduces
rate of contaminant transfer from a disposal site.
However, long-term cumulative contaminant migration
could be important. In particular, it is not clear
that reductions in long-term trace contaminant avail-
ability would take place when fly ash is used as a
stabilization additive to a waste initially containing
no ash. However, migration of contaminants to the
environment at a slower rate is more desirable.
4-48
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Cementitious stabilization process, because of
increased particle size, may also be considered miti-
gative of the potential for post-disposal fugitive
particulate emissions from dry FGC waste disposal
operations, and may minimize or prevent gaseous
emissions by reducing exposure of waste to water and
biological organisms.
In ocean disposal, cementitious stabilization may
remove liabilities of FGC wastes as benthic sub-
strates and as sources of sulf±te-related depletion
of dissolved oxygen. However, questions of sulfite
and trace contaminant availability, among others,
preclude definitive judgment on this issue at this
time.
Forced Oxidation; The intentional production of
sulfate-rich, rather than sulfite-rich FGC wastes, is
presently a subject of considerable interest. In
ocean disposal, the sulfate-rich products of forced
oxidation would have the obvious advantage of miti-
gating the potential for sulfite-related depletion
of dissolved oxygen. This advantage would be shared
in land disposal operations (especially wet impound-
ments) , but its relative importance is less clear. A
dominant question concerning the mitigative potential
of forced oxidation for land disposal is whether or
not the process results in increased or decreased
physical stability. Based on experience with soils,
gypsum FGD wastes comprised of relatively uniform,
sand-sized particles may exhibit considerable failure
potential in the absence of: 1) effective compaction
and dewatering, and/or 2) codisposal with materials of
varying particle size (i.e., fly ash). However, if
FGD gypsum is analogous to phos-gypsum, recrystallization
mechanisms occurring in the disposal pile may improve stability.
4-49
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c. Co-disposal of Wastes and Creation of Waste/Soil Mixtures
Although the term co-disposal is often used in reference to the
creation of disposal mixtures of two waste streams (e.g., FGD
wastes and coal ash), it is used here to imply a broader range
of potential opportunities. Specifically, for land disposal
of FGD wastes, "co-disposal" might also include the application
of technologies for the creation of soil/waste mixtures. If soils
with the proper characteristics are available, the creation of
soil/waste mixtures may be an alternative to the addition of fly
ash where only limited increases in physical stability are desired
in a disposal operation, or where trace contaminant availability
needs to be reduced to facilitate revegetation or decrease water
quality impacts. Traditional co-disposal involving fly ash plus
FGD waste appears to have substantial advantages over independent
disposal in terms of improved physical stability and (potentially)
decreased permeability. This might be especially relevant to
sulfate-rich FGC wastes of uniform particle size. However, in
some situations the extent to which the ash serves as a reservoir
of certain trace contaminants could prove a liability from the
standpoint of potential water quality degradation.
d. Use of Liners: Liners may not be usually required for FGC waste
disposal except under certain site specific conditions. However,
the use of liners may be desirable. Field experience with liners
for FGC waste disposal at present is limited, but ongoing and
recently announced programs are likely to close this gap.
4.6.5 Future Research Needs
A number of programs have been undertaken (and are in progress)
by the Environmental Protection Agency (EPA), the Department of Energy
(DOE), the Electric Power Research Institute (EPRI), and others.
These efforts have provided much of the baseline information for
environmental assessment. Provided these programs continue, additional
data and insight permitting better environmental assessment will be obtained .
4-50
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Research needs pertinent to environmental assessment of FGC disposal
are:
a. Acquisition of field data on the actual impacts of full-
scale disposal operations under varying environmental
conditions. Field-scale monitoring of large disposal
operations over a period of several years is warranted.
EPRl's proposed program at Conesville Plant of Columbus
and Southern Ohio Electric is one such example. EPA is
also planning an extensive two-year study on characteriza-
tion and environmental monitoring of full-scale utility
disposal sites.
b. A corrollary of the above would be the development of
correlations and tools of extrapolation to relate exist-
ing lab/pilot scale data on physical stability and water
quality impacts to full-scale field data.
C. Integrated study and evaluation of the environmental
trade-offs in co-disposal of various FGD wastes and var-
ious coal combustion ashes. (It appears that this type
of initiative could emphasize laboratory work with limited
pilot and full-scale field verification.)
d. Development of basic data (laboratory and field-scale) on
the biological impact potential of principal land-based
FGC waste disposal options, especially data relating to
water-related impacts of major soluble species and trace
contaminants. Typical questions are:
• What are the biological and health effects of mix-
tures of trace metals (in the form found in liquors),
such as zinc, copper, lead, mercury, cadmium or
nickel in combination with selenium in particular, but
also in combinations with other trace metals? Are
synergistic effects significant?
4-51
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• What is the uptake of potentially toxic materials by
vegetation and wildlife associated with disposal areas?
• What are the levels of ambient concentration of waste-
related potentially toxic materials in vegetation and
surface water that may produce chronic health problems
for wildlife?
EPA is presently supporting biological testing work on FGC
wastes at Oak Ridge National Laboratory and will support
field scale testing beginning in 1980 at TVA.
e. Development of basic (laboratory and field) data on the
potential for fugitive particulate emissions from areas
previously used for the dry disposal of FGC wastes.
f. Socio-economic impacts of FGC waste disposal on land need
to be better defined.
In the future, FGC waste generation will not be limited to those
from coal-fired utility systems. Coal utilization in industrial boilers
(25 MW or larger) is also likely to grow substantially in the future.
FGC wastes from such coal-fired industrial boilers (which may be analogous
in composition to solid wastes from utility boilers or maybe liquid
wastes) present additional waste management issues due to differences in
distribution of generation facilities, in quantity of FGC wastes generated
at each facility and other factors. These issues also require further
evaluations and study.
4-52
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4.6.6 Economics of FGC Waste Disposal
The economics of waste disposal is quickly becoming one of the most
important factors in the implementation of FGC systems. Generic studies
of FGC process technologies and the evaluation of specific process
applications now routinely incorporate analyses of waste processing and
disposal costs. In addition, numerous generalized economic studies have
also been undertaken. These studies basically fall into one of two
categories. First, studies involving conceptualized designs and generic
cost estimates for a variety of different waste types and disposal
options using a model plant approach in order to evaluate the comparative
economics of disposal alternatives and to investigate the sensitivity
of waste disposal costs to a range of design and operating parameters; and
second, economic or cost impact studies focused on assessing the waste
disposal costs on an industry-wide basis for compliance with RCRA and/or
other regulatory scenarios.
At present, there is little published cost data on full-scale
commercial disposal operations to provide a basis for these generalized
studies. More accurate accounting of waste disposal costs is expected
to be employed, especially for new plants. Additional cost data are
also expected to become available from a number of FGD demonstration
systems such as the dry impoundment at LG&E's Cane Run Station and the
mine disposal operation at the Baukol-Noonan mine in North Dakota. In
addition, the planned full scale utility waste disposal study at a
number of sites by the EPA will develop broad baseline data on costs of
FGC waste disposal.
An overview of the principal waste disposal cost studies is provided
in the following sections. A more detailed review is given in Volume 5
of this report. All major cost studies to date have been based on
existing practices and do not fully consider RCRA related requirements.
Some studies on RCRA related impacts are expected by mid-1979.
4-53
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4.6.6.1 Costs of Waste Disposal Alternatives
Fly Ash
A number of generalized economic studies relating to the disposal of
fly ash have been performed. One of the more important of these is the
study conducted by NUS [49] sponsored by the Utility Water Act Group.
The purpose of this study was to evaluate the costs associated with dry
fly ash removal systems for new power plants comparing dry ash handling
and disposal versus wet handling and disposal. The results of this study
indicate that the cost of a dry system may be considerably less expensive
than that for a wet system. For the 1,000-MW model plant considered,
waste handling and disposal costs ranged from $8 to $17 per dry ton with
the cost for a dry system almost half that for a wet system.
FGD Wastes
Most of the studies of a general nature developing comparative
economics for waste disposal alternatives and completed prior to 1979,
have been sponsored either by the EPA or EPRI. Most of these have dealt
with existing practices for waste disposal and have not attempted to spe-
cifically address the possible impacts of RCRA on design and operation.
Such studies have been performed by TVA [50, 51], Aerospace [52, 58-62],
Michael Baker, Jr. Inc. [53], and Arthur D. Little [54]. All of the
studies involve medium or high sulfur coal-fired power plants and all use
a model plant approach for preparing cost estimates. Table S.17 summarizes
these studies with regard to their general scope and the cost bases
employed. For those studies that are now ongoing, base years for most
recent cost estimates are shown.
Unfortunately, the design and operating assumptions in these various
studies as well as the battery limits assumed for the disposal systems
differ. Costs are generally presented in lump sum form, covering the
entire waste processing and disposal facilities, and breakout of modular
costs for different sections of the waste disposal plant and/or waste
disposal operations are usually difficult. Hence, direct comparisons of
cost estimates frequently are not possible. In this regard, efforts are
now underway to develop a standard cost basis for future cost analyses of
FGD systems and disposal operations prepared by EPA contractors.
4-54
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FGD WASTES
Contractor
TVA
EPA
Table S.I7
Summary of General Conceptualized Cost Studies for FGC Waste Disposal
Type of Scrubber Mode of Operation
Disposal Options Considered
Wet Surface Underground Ocean No. Cases Base Year Reference
High S Oxidatior Onfy -t_Ash. _ Landfill _Pond__ Mine Mine
Sponsor Conv. Forced
SO,
SO,,
Dry
Limestone3 Limestone
150+ 1979/1980 50, 51
Aerospace
EPA Limestone Limestone /
-30 1976/1977 52
Michael Baker EPRI Lime
4 1976
53
ADL
EPA Lime
16 1977
I
m
Ln
NUS
UWAG
Fly Ash
Only
1974
49
Four cases include lime scrubbing.
Included only for forced oxidation.
cNumber of cases studied varies with report.
Source: Arthur D. Little. Inc.
-------
The most comprehensive of the studies performed to date is that
being conducted by TVA. More than 150 cases and case variations are
being evaluated including dry impoundment, wet ponding, and surface mine
disposal of stabilized and unstabilized wastes. For the most part, costs
have been based upon wastes from either conventional direct limestone
scrubbing systems or limestone scrubbing systems incorporating forced
oxidation; however, a few cases of conventional direct lime scrubbing
have also been considered. All of the costing work has been rather
general in nature, focusing on gross effects of major parameters and
variables on disposal economics. The principal variables studied include
power plant capacity, sulfur and ash content of the coal, distance to the
disposal site, land requirements and availability, and waste processing
requirements.
Generally, costs are presented on integrated system basis (including
both waste processing and disposal) starting at the scrubber battery
limits. Simplifying assumptions have been made with regard to the engi-
neering properties of various types of wastes and equipment design para-
meters. The design bases are generic and partly based on prototype data*
they represent some engineering studies. Similarly, the cost estimates
are based on cost studies of the processes. The estimates are general
in the sense that they do not represent actual systems. Actual systems
are often very site specific in nature. The properties and equipment
design bases are now being reviewed and modified to more closely reflect
variations in different types of wastes, and efforts are being made to
provide costs on a modularized basis to allow addition and deletion of
processing units for comparison with other cost estimates.
A summary of disposal costs estimated by TVA for a model 500 MW
utility burning typical high sulfur midwestern coal (3.5% and 5.0% sulfur)
is presented in Table S.18. Only costs for onsite disposal (one mile
from the plant) of ash and FGD wastes from a direct limestone scrubbing
system are shown. For wet ponding, the costs are based upon simultaneous
fly ash and SO- scrubbing; and the range of costs shown reflects variations
in sulfur content of the coal, land availability (constraints on the
4-56
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Table S.18
Summary of TVA Cost Estimates for FGC Waste Disposal
Basis: 500 Mw Plant (30-year lifetime)
High Sulfur Coal
7,000 hours operation/year (years 1-10)
Onsite Codisposal (1-mile)
Limestone Scrubbing
Coal - 3.5 and 5.0% sulfur, 16% ash
Mid-1980 Cost Basis
Annual Revenue Requirements ($/dry ton)a
Disposal Mode Wet Ponding Dry Impoundment
__ (Simultaneous Ash & S02 Scrubbing) (Separate Ash & SO Control)
Unstabilized $6-12
Ash-Blending - $8-9
b c
Stabilized $14-20 $11-13
Unstabilized Gypsum
(Forced Oxidation) - 6-8
^o monitoring costs included
K R
Stabilization via Dravo's Synearth Process
p
CStabilization via lUCS's Poz-0-Tec Process
Source: [50,51]
4-57
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acreage of the site), pond lining requirements (type of lining) and the
density of the settled waste.
The basis used by TVA in estimating dry impoundment costs differed
depending upon the type of waste. For conventional sulfite-rich wastes,
it was assumed that the wet scrubber would follow an electrostatic pre-
cipitator. The dry ash would then be admixed with the FGD wastes either
with or without the addition of stabilization chemicals prior to landfill.
In the case of gypsum from forced oxidation systems, it was assumed that
blending of dry ash with the gypsum would not be required due to its
better dewatering and handling properties. Hence, simultaneous ash and
SC>2 removal was assumed for forced oxidation systems. The ash blending
and stabilization cases for conventional wastes, therefore, include not
only process equipment but also the incremental cost of an ESP over a
wet particulate scrubber neither of which are included in the forced
oxidation system. (It should be noted that forced oxidation systems
have not yet been fully demonstrated on high sulfur coals and the use of
wet particulate scrubbers may be impractical under the revised NSPS.)
The range of costs shown for dry impoundments incorporates variations
in the sulfur content of the coal, and, for stabilization, variations in
the additive feed rate. No variations in land availability were considered
and it was assumed that no lining would be required.
Power plant size (quantity of waste) and distance to the disposal
site were determined to be particularly important factors in waste dis-
posal costs. Over the range of power plant capacity from 200 Mw to 1500 Mw
annual revenue requirements for waste disposal varied according to a
capacity (quantity) factor of 0.55-0.65. Increasing the distance to the
disposal site from 1 mile to 10 miles, increased revenue requirements by
30-40% for dry impoundment and 40-125% for wet ponding.
Another important factor affecting wasted disposal costs for a new
plant is the actual on-stream time for the plant. The costs shown in
Table S-18 are based upon an estimated annual average of 7000 hours of
operation per year, which might be experienced during the first ten years
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of the plant life. However, as the plant ages, the annual operating hours
will generally decrease. TVA estimates that the actual annual average
on-stream time of a plant over its 30-year lifetime would be expected on
the order of 4500 hours/year. Use of this lower operating factor would
obviously indicate higher cost estimates for waste disposal reported on
a $/ton basis. However, while use of such a lifetime average operating
factor may provide a higher estimate of disposal costs, a proper compari-
son of costs can only be made on a levelized basis by discounting future
costs.
Aerospace has been preparing cost estimates for FGC waste disposal
since 1974 under contract to EPA. These estimates have been updated and
revised as more waste properties data and disposal operating requirements
have become available. Much of the work has focused on various types of
wet ponding of wastes including disposal of unstabilized waste in ponds
provided with under drainage. Costs have also been developed for land-
filling of stabilized wastes, surface disposal of gypsum and production
of wallboard grade gypsum from limestone forced oxidation systems (for
comparison with conventional limestone scrubber waste disposal). In
general, the cost estimates for wet ponding are lower than those prepared
by TVA (on an equivalent basis), but there are significant differences
in assumptions for design of the pond and pipeline transport systems.
The costing by Michael Baker, Jr., [53] and Arthur D. Little [54] are
more limited in scope than either the Aerospace or TVA studies. The
Michael Baker analysis was part of a larger study of stabilization
technology sponsored by EPRI, and involved a comparison of landfilling
stabilized and unstabilized (ash-blended) wastes. Cost estimates, based
upon inputs from commercial stabilization process suppliers, indicated
that stabilization would result in about a $.70/dry ton increase in
cost over simple ash blending for a 1000 Mw, high sulfur coal-fired plant
assuming an additive feed of 2 weight percent (dry basis). While no
equivalent case was considered by TVA, interpolation between the serious
cases considered indicate a difference of about twice this amount based
upon TVA's work.
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Waste disposal cost estimates prepared by Arthur D. Little focused
exclusively on disposal of wastes in the ocean and mines. These costs
were developed as part of an ongoing study for the EPA to evaluate the
feasibility of ocean and mine disposal. The estimates were based upon
very generalized conceptual systems. Unlike the other costing work
described above, these costs do not include waste processing; rather
only the waste transport and disposal operations. Based upon a prelimin-
ary analysis, waste disposal in on-site mines was found to be slightly
less expensive than conventional dry impoundment. Ocean-disposal costs
varied greatly depending upon the disposal mode and distance off-shore;
however, some ocean disposal methods were found to be cost competitive
with land disposal, especially where off-site land disposal would be
required. These costs are being reviewed and additional mine disposal
costs are being independently prepared by TVA.
In developing generalized cost studies for waste disposal, such as
those discussed above, it is important to recognize the fact that it is
frequently difficult to totally divorce the waste disposal system from
the scrubber. This is particularly true when comparing systems with
different types of ash collection or scrubber technology (e.g., forced
oxidation), and it may be equally important when developing the design
basis for the waste processing facilities. In most cases, waste pro-
cessing will be coupled directly to FGC scrubbers or thickeners, and the
waste processing plant must be capable of handling the short-term sustained
peak loads expected for the FGC system itself, especially with regard to
variations in coal sulfur and ash content. Such considerations need to
be factored into the capacity of the equipment itself. Alternatively,
provision must be made for a buffer between the FGC system and parts of
the waste processing plant (such as interim storage of filter cake and
ash). It is best, therefore, to evaluate waste disposal in the context
of total FGC system costs rather than independently.
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4.6.6.2 Economic (Cost) Impact Studies
Two studies have recently been completed assessing the impact of
waste disposal regulations on the industry-wide costs for FGC waste
disposal for the electric utility industry. One study performed by
Radian [55] for the U.S. EPA (IERL) focused on the cost impact of RCRA
on future FGC waste disposal. The other study performed by SCS Engineers
[56] for the U.S. EPA (MERL) assessed the impact of a range of different
regulatory scenarios on the cost of waste disposal. Draft reports on
both of these studies are now in review.
The results of the Radian assessment indicate that the capital
costs related to the disposal of utility nonhazardous wastes will
increase about 36%, or about one billion dollars (in mid-1979 dollars)
for plants in operation by 1985 due to compliance with RCRA. However,
annual revenue requirements are estimated to increase by only about 6%,
or about 70 million dollars. These estimates were based upon a model
plant cost estimation approach using a 1,000-MW plant. The major impacts
of RCRA were assumed to be in distance from plants to disposal sites
(greater distances being required under RCRA to locate suitable sites)
and the use of lined rather than unlined ponds.
The SCS study assessed the impact of five different regulatory
scenarios ranging in severity from regulation at the state level with
no change in current disposal practices to enforcement of regulations
at the federal level with chemical stabilization universally required
(where specifications would be given for acceptable stabilization
techniques). Costs were based upon a set of 10 model plants representing
different geographic regions, coal types, and rural versus urban locales.
Waste disposal cost estimates were prepared for six different disposal
options drawing from the TVA cost model previously discussed. Results
indicate that annual revenue requirements for plants in operation by
1985 can increase by up to 75-80%, or 2.3 billion dollars (1980 dollars)
under the most stringent regulatory scenario assumed. This most stringent
scenario would correspond to an increase of about 1.3 mills/kwh in con-
sumer power costs (1980 dollars).
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A.6.6.3 Econonic Uncertainties and Data Gaps
There are a number of uncertainties concerning FGC waste disposal
that importantly affect overall disposal economics and viability of dis-
posal modes. We feel that the two most important relate to land use/
availability/cost and long-term maintenance of retired disposal sites.
They are not strictly data gaps in the sense that they can be readily
resolved through current studies and R&D efforts; rather, they are social/
technical/economic issues that will require continuing consideration and
evaluation with increasing coal utilization and the growing implementation
of nonrecovery FGC systems.
Current data gaps related to the economics of FGC waste disposal
which can be addressed by government and/or industry initiatives include
both cost information per se as well as waste properties and disposal
requirements directly impacting disposal costs. The most important of
these data gaps are the following:
• There is a general lack of reliable cost information from
commercial operations of most types of FGC disposal. This
is particularly true of wastes from industrial boilers which
are likely to become more important in the future. Ongoing
and planned EPA projects should at least partially fill this
gap.
• There have been no definitive studies on the disposal of
wastes from dry sorbent systems and the associated costs.
• Existing physical and engineering properties data on some
types of wastes are not adequate as a basis for developing
designs needed for reliable estimates of cost-effective
disposal systems. Examples include: the disposal of gypsum
untreated in dry impoundments; the amount of ash and lime
required for adequate stabilization of some sulfite-rich
wastes; and the potential use of stabilized FGC waste mate-
rials as liners for dry impoundments of blended coal ash/
FGD wastes (i.e., as disposal of coal ash/FGD wastes).
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• RCRA is likely to impose some additional costs due to
constraints pertaining to waste analysis, site selection,
monitoring, closure. These need to be defined further.
Ongoing EPA and DOE studies are expected to provide
data on this issue.
4.7 FGC Waste Utilization
At present, although utilization of FGC wastes is feasible, the
percentage of FGC wastes generated that is utilized in the United States
is modest in comparison with other industrial nations. In 1977, 21% (12.7
million metric tons) of the coal ash and none of the FGD wastes generated
were utilized [7]. Many European countries and Japan utilize proportion-
ately much more of the FGC wastes that they produce than the United States.
Although differences in raw material availability and marketability account
for some of this difference, in general there are institutional factors
which favor increased utilization abroad and hinder expansion of domestic
utilization. This situation may change as the utilization of coal for
electric power expands and an energy and resource conservation ethic
begins to take shape.
The principal present and potential uses of coal ash are:
• Structural fill (landfill cover, land recovery, surface mine
reclamation, highway or similar embankments, etc.)
• Use in building materials (cement, concrete block, aggregate,
etc.)
• Paving materials (road base, etc.)
• Agricultural use (soil amendment or stabilizer)
• Environmental uses (road icing control, sludge dewatering,
neutralizing, acid mine drainage, etc.)
• Recovery of chemicals (alumina, calcium, oxide, etc.)
Commercial utilization of coal ash is expected to increase in the
United States , continuing the historical trend. The increasing reliance
on coal as a utility fuel with attendant increases in ash production may
result in the percentage of utilization being unchanged or even decreasing
despite efforts to promote ash utilization through increased market
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visibility and technological development. Tightening environmental con-
trol regulations concerning disposal of wastes and constraints on land
availability in some areas, however, would continue to enhance the
attractiveness of utilization.
In contrast to coal ash, there are essentially no markets developed
for utilizing wastes from nonrecovery FGD systems in the United States,
and the utilization of FGD sludge is expected to progress more slowly
because of the need to demonstrate commercial viability.
In Japan, gypsum is produced in FGD systems and is marketed for use
in wallboard production and the manufacture of cement. However, in the
United States, there is little current market for gypsum as a byproduct
material. Studies indicate the possibility that production of FGD gypsum
for utilization may offer economic advantages over FGC waste disposal in
some site-specific cases; in particular, use in portland cement manufacture
may be promising [65], The use of FGD sludge from nonrecovery FGD proc-
esses as a filler material and fertilizer and the use of sulfur from
recovery FGD processes are potential utilization options. However, these
are not considered promising at this time. Further development of the
fertilizer production process is needed to establish its viability, as
are plant toxicity studies. Conversion of FGD sludge to elemental sulfur
with recovery of the absorbent for recycle to the scrubber has been studied.
Other possible uses of nonrecovery FGD wastes that continue to be explored
include use as a concrete additive, a low grade construction base for
construction of artificial reefs, for soil amendments, and for mine sub-
sidence control.
Economics of utilization vary widely with site- and system-specific
conditions and, hence, are not generalized here. Available data are
assessed in Volume 4 of this report.
As an alternative to nonrecovery FGD systems, recovery FGD systems
produce sulfur or sulfuric acid as a byproduct. Markets for these prod-
ucts, though, are quite location-specific and the cost for producing the
byproduct with FGD systems is high. Successful applications will prob-
ably be in specific locations where a market for the products exists or
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in areas where availability of disposal options for nonrecovery processes
is so constrained that the cost of waste disposal is high. It is im-
portant to note that most recovery systems also produce wastes; e.g.,
blowdown from prescrubbers (which remove fine particulate matter and
chlorides from the flue gas prior to its entering the sulfur dioxide
absorber) and blowdown of contaminants from the regenerative portion of
the process.
A variety of explanations have been given for the slow growth of
utilization in the U.S., usually in some way related to the research
perspective of the organization doing the assessment. Specifications,
quality control, lack of markets, consumer bias, lack of technical
development, and many other reasons have been put forward as
hindering increased utilization of ash and sludge in the United States.
All of these reasons are valid in at least some instances, and some-
times across the board. However, on balance a combination of three
types of factors constrain FGC waste utilization:
• Technical considerations, particularly in comparison with
alternative materials;
• Institutional barriers related to poor understanding of
the byproducts and failure to develop markets by either
the utility industry or user industries; and
• Possible environmental concerns related to some uses.
Considering the anticipated growth in the generation of FGC wastes,
removal of or reduction in barriers to FGC waste utilization becomes
important. In some cases, technical problems preclude successful large-
scale utilization. The more serious impediments are apparently insti-
tutional in nature and require study and assessment.
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4.8 Emerging Technologies and the Future
At present conventional coal combustion remains the dominant method
of electric power generation. As the Nation continues its increasing
reliance on coal, this trend will continue. However, several R&D efforts
at EPA, DOE, EPRI and other organizations are being focused on ways to
burn or utilize coal more effectively.
Any possible alternatives for the utilization of coal must deal with
the following issues:
• Air pollution control leading to particulate and sulfur
oxides control (in future NO control also).
X
• Water pollution control leading to effluent standards
and water management for recycle/reuse.
• Solid waste management to deal with the ultimate disposal
of wastes from the above two.
Potential options to use coal are:
a. Conventional combustion including flue gas cleaning (FGC).
b. Coal cleaning and conventional (or other) combustion
of coal with adequate flue gas control.
c. Fluid bed combustion (FBC).
d. Low Btu gas and combined cycles.
e. Coal liquefaction.
f. Magnetohydrodynamics (MHD).
Considering coal utilization over the next twenty years, some of
these technologies are likely to reach significant levels of commercializa-
tion. It should be emphasized that all these technologies will have their
own waste management problems. All these technologies will generate
wastes; however, quantity, the physical and chemical characteristics and
point of generation (mine end, utility end, or other) of the wastes
would be different from those associated with conventional coal combustion.
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Coal Cleaning
Coal cleaning processes can be broadly categorized into
• Mechanical coal cleaning.
• Advanced cleaning processes.
Mechanical Cleaning; Mechanical cleaning processes are based
on differences in specific gravity or surface characteristics
of the materials being separated. They can be designed to
remove a large fraction of the pyritic sulfur, generally
the major part of the sulfur in high-sulfur coals. Pyritic
sulfur occurs as discrete particles. It is much heavier
than coal, with a specific gravity of 5.0, compared to
coal's 1.4. Hence, when raw coal is immersed in a dense
medium, the coal floats and the pyrites sink. This process
is widely used to remove shale and rocks, etc. (specific
gravities from 2 to 5) but pyrite is more dispersed and
finer crushing of the coal than is generally practiced for
shale and rock removal alone is required to free it for
removal.
Advanced Cleaning Processes: Several physical and/or
chemical treatments have been proposed for improved pyritic
sulfur removal.[63] These are:
(1) High-gradient magnetic separation (HGMS) -
separation of pyrite by exploiting its
magnetic properties.
(2) Magnex process - a "pretreatment" process
allowing better magnetic separation.
(3) Meyers process - a chemical leaching of
pyrite from the coal.
(4) Otisca process - washing with a heavy
liquid rather than a water suspension.
(5) Chemical comminution - a "pretreatment"
process that chemically breaks down the
coal to smaller sizes.
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(6) Ledgemont oxygen leaching process -
dissolution of pyrites and some organic sulfur
using a process simulating the production of
acid mine water.
(7) Bureau of Mines/DOE oxidative desulfurization
process - a higher temperature, air instead of
oxygen variation of the ledgemont process.
(8) Battelle hydrothermal process - leaching of
pyrites and organic sulfur under high pressure.
(9) KVB process - gaseous reaction of the sulfur
with nitric oxide.
b. Fluid Bed Combustion (FBC)
Fluidized-bed combustion (FBC) is an important technological
alternative for industrial applications and perhaps coal-based
power generation. Its basic principle involves the feeding of
crushed coal for combustion into a bed of inert ash mixed with
limestone or dolomite. The bed is fluidized (held in suspension)
by injection of air through the bottom of the bed at a controlled
rate great enough to cause the bed to be agitated much like a
boiling fluid. The coal burns within the bed, and the SO
X
formed during combustion react with the limestone or dolomite
to form a dry calcium sulfate.
FBC has the following advantages:
• The flexibility to burn a wide range of rank and quality
of coals.
• A higher heat transfer rate than in conventional boilers,
which reduces the requirements for boiler tube surface
and furnace size and also lowers capital costs.
• An increased energy conversion efficiency through the
ability to operate without the power requirements
needed for flue gas cleaning.
• Reduced emissions of SO and NO .
x x
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• A solid waste potentially more readily amenable and
acceptable to disposal than that from a wet-scrubber
applied to conventional boilers although current
quantities on a dry weight basis will be substantially
higher because of high stoichiometric requirements.
• The potential for operation at an elevated pressure
sufficient to use with a combined gas-turbine/steam-
turbine cycle for generating electricity at higher
efficiency.
c. Low Btu Gas and Combined Cycles
Coal can be gasified to produce a low-Btu gas. Since the
gas cannot economically be stored or shipped more than a few
miles before combustion, it is effectively a form of direct
combustion of coal. The gas is cleaned before burning so
that no emission controls are required at the combustion
facility. Low-Btu gas can be burned directly in a boiler
to produce steam for industrial use or for the production of
electricity in a conventional steam turbine. Alternatively,
the gas generator can be integrated with a combined cycle
plant. EPRI [64] concludes that this combination offers
potential advantages over conventional combustion. Texaco [64]
is planning to proceed with a demonstration facility (90-100 Mw)
based on the Texaco gasifier and a combined cycle power plant
at Southern California Edison facilities.
d. Coal Gasification to High Btu Gas
Gasification technology to produce high Btu gas is also
under development. However, this method is not focused on
electric power production.
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e. Coal Liquefaction
Conversion of coal to liquid hydrocarbons is also under
intense study. Processes for liquefying coal can be one of
three general categories.
(1) Conversion to low Btu gas followed by catalytic synthesis,
(2) Pyrolysis.
(3) Direct liquefaction involving solvent refining or
catalytic hydrogeneration.
Three processes all based on direct liquefaction
(Exxon Donor Solvent, H-Coal and Solvent Refined
Coal-SRC-II) are under development.
f. Magnetohydrodynamics (MHD)
The interest in MHD steins mainly from high expected thermal
efficiency for an entire system including a conventional steam
cycle. In MHD generators, a stream of very hot gas (roughly
5,000°F), flows through a magnetic field at high velocity.
Because the gas at high temperatures is an electrical conductor,
an electrical current is produced through electrodes mounted
in the sides of the gas duct. Coal-fired systems are under
research and study.
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Power 120 (4), 1977.
2. Geological Survey Circular 765. U. S. Geological Survey, Washington
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3. National Electric Reliability Council 7th Annual Review of Overall
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R-l
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14. Ifeadi, C. N. and H. S. Rosenberg, "Lime/Limestone Sludges - Trends
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Related to Steam Electric Power Generating Point Source Category
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Environmental Protection Agency, Washington, D. C., 20460, Draft
Report May 1978.
51. Barrier, J. W., H. L. Faucett, and L. J. Henson, "Economics of
Disposal of Lime/Limestone Scrubbing Wastes," Tennessee Valley Authority
EPA 600/7-78-023a, Environmental Protection Agency, Washington, D. C.,
February 1976.
52. Leo, P. L. and J. Rossoff, Aerospace Corporation, "Controlling SO
Emissions from Coal-Fired Steam-Electric Generators: Solid Waste
Impact," Two Volumes, EPA Rpt. No. EPA-700/7-78-044a and b. Envir-
onmental Protection Agency, Washington, D. C. , 20460, 1978.
53. "State of the Art of FGD Sludge Fixation," W. A. Duvel, W. R.
Gallagher, R. G. Knight, C. R. Kolarg, R. J. McLaren, Michael Baker, Jr.,
Inc., EPRI FP-671, Project 786-1, Electric Power Research Institute,
Palo Alto, Ca. January 1978.
54. "An Evaluation of the Disposal of FGD Wastes in Mines and the Ocean -
An Initial Assessment," R. R.Lunt, et al. EPA-600/7-77-051 Environmental
Protection Agency, Office of Research and Development, Washington, D.C.
20460, Mayl977.
R-4
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55. Jones, B. F., et al., Radian Corporation, "Study of Nonhazardous
Wastes from Coal-Fired Electric Utilities," DCN 200-187-41-08 Report
to EPA-IERL, Research Triangle Park, N.C., 27711, Draft Final Report,
December 15, 1979.
56. SCS Engineers "Economic Impact of Alternative Flue Gas Desulfurization
(FGD) Sludge Disposal Regulations in the Utility Industry" Report
to EPA Municipal Environmental Research Laboratories, Cincinnati, Ohio,
Draft Final Report, January 1979.
57. "Fuel Exemptions for Existing Plants", Power, April 1979, p. 20.
58. Leo, P. P. and Rossoff, J., Control of Waste and Water Pollution
from Coal-Fired Power Plants: Second R&D Report, EPA-600/7-78-224,
November 1978.
59. Fling, R. B., et al, Disposal of FGC Wastes: EPA Shawnee Field
Evaluation: Initial Report, EPA-600/2-76-070, March 1976.
60. Fling, R. B., et al, Disposal of Flue Gas Cleaning Wastes: EPA
Shawnee Field Evaluation: Second Annual Report, EPA-600/7-78-024,
February 1978.
61. Fling, R. B., et al, Disposal of Flue Gas Cleaning Wastes: EPA
Shawnee Field Evaluation: Third Annual Report, Published as an
EPA Report.
62. Rossoff, J., et al, Disposal of By-Products from Nonregenerable
Flue Gas Desulfurization Systems: Initial Report, EPA-650/2-74-037-a,
May 1974.
63. Personal communication from J. D. Kilgroe of EPA to C. J. Santhanam,
Arthur D. Little, Inc., February 1979.
64. Personal communication from F. Guptill of Texas Development to
C. J. Santhanam, Arthur D. Little, Inc., January 1979.
65. Ash at Work, Vol. X, No. 4, Page 4, 1978.
R-5
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TECHNICAL REPORT DATA
(Please read Infractions on the reverse before completing)
REPORT NO,
EPA-600/7-80-012a
2.
3. RECIPIENT'S ACCESSION NO.
.. TITLE AND SUBTITLE
Waste and Water Management for Conventional Coal
Combustion Assessment Report—1979
Volume I. Executive Summary
5. REPORT DATE
January 1980
6. PERFORMING ORGANIZATION CODE
c.J.Santhanam. R.R.Lunt, C.B.Cooper,
D.E.Kleinschmidt. I.Bodek, and W. A. Tucker (ADL);
and C.R.Ullrich (U. of Louisville)
8. PERFORMING ORGANIZATION REPORT NO
PERFORMING ORGANIZATION NAME AND ADDRESS
Arthur D. Little, Inc.
20 Acorn Park
Cambridge, Massachusetts 02140
10. PROGRAM ELEMENT NO.
EHE624A
11. CONTRACT/GRANT NO.
68-02-2654
2. SPONSORING AGENCV NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final; 9/77 -8/79
14. SPONSORING AGENCY CODE
EPA/600/13
^.SUPPLEMENTARYNOTES IERL-RTP project officer is Julian W. Jones, Mail Drop 61, 919/
541-2489.
6. ABSTRACT The j^p^t; js ^ executive summary, the first of five volumes giving a de-
tailed assessment of the state-of-the-art of water and waste management technology
for conventional combustion of coal. Various R and D programs sponsored by EPA
and private industry have achieved significant results in many areas. Substantial
progress has been made in characterizing major wastewater streams and in deter-
mining physical, chemical, and engineering properties of flue gas cleaning (FGC)
wastes. Overall water management studies have shown that more efficient water
recycle/reuse can be achieved, and can serve as models for water management
plans in new facilities. Generation of FGC wastes is expected to increase dramati-
cally. Utilization of FGC wastes is also expected to grow, but much more slowly.
Major FGC waste disposal methods are ponding, disposal in managed fills, and mine
disposal. Progress in dewatering and stabilization processes is expected to increase
the relative attractiveness and viability of the latter two methods. Potential environ-
mental impacts are primarily contamination of surface water and groundwater, and
land degradation (physical instability, large land requirements); actual impacts are
site- and system-specific. Applying appropriate control technology can mitigate
adverse impacts. Disposal costs are $9-15 per dry ton of FGC wastes.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Pollution
Coal
Combustion
Assessments
Management
Waste Disposal
Water
Flue Gases
Cleaning
Pollution Control
Stationary Sources
Flue Gas Cleaning
13B
21D
21B
14 B
05A
07B
13H
IS. DISTRIBUTION STATEMEN'
Release to Public
19. SECURITY CLASS (This Report)
Unclassified
20 SECURITY CLASS (This page)
Unclassified
21. NO. OF PAGES
99
22. PRICE
EPA Form 2220-1 <»-73)
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