oEPA
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 2771 1
EPA-600/7-79-073c
June 1979
Environmental
Assessment of Coal
Cleaning Processes:
First Annual Report;
Volume II. Detailed Report
Interagency
Energy/Environment
R&D Program Report
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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-600/7-79-073C
June 1979
Environmental Assessment of Coal
Cleaning Processes: First Annual Report
Volume II. Detailed Report
by
A. W. Lemmon, Jr., S. E. Rogers, G. L. Robinson
V. Q. Hale, and G. E. Raines
Battelle-Columbus Laboratories
505 King Avenue
Columbus, Ohio 4320I
Contract No. 68-02-2163
Task No. 11
Program Element No. EHE623A
EPA Project Officer: James D. Kilgroe
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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FOREWORD
Many elements and chemical compounds are known to be toxic to man and
other biological species. But, our knowledge concerning the levels and
conditions under which these substances are toxic is extremely limited.
Little is known concerning the emission of these pollutants from industrial
processes and the mechanisms by which they are transported, transformed,
dispersed, or accumulated in our environment.
Portions of the Federal Clean Air Act, the Resource Conservation
Recovery Act, and the Federal Water Pollution Control Act require the U.S.
Environmental Protection Agency (EPA) to identify and regulate hazardous
or toxic substances which result from man's industrial activities. Industrial
pollutants are often identified only after harmful health or ecological
effects are noted. Remedial actions are costly, the damage to human and
other biological populations is often irreversible, and the persistence of
some environmental contaminants may endanger future populations.
EPA's Office of Research and Development (ORD) is responsible for health
and ecological research, studies concerning the transportation and fate of
pollutants, and the development of technologies for controlling industrial
pollutants. The Industrial Environmental Research Laboratory, an ORD
organization, is responsible for development of pollution control technology
and conducts a large environmental assessment program. The primary objectives
of this program are:
• The development of information on the quantities of
toxic pollutants emitted from various industrial
processes—information needed to prioritize health
and ecological research efforts.
• The identification of industrial pollutant emissions
which pose a clearly evident health or ecological
risk and which should be regulated.
• The evaluation and development of technologies for
controlling pollution from these toxic substances.
The coal cleaning environmental assessment program has as its specific
objectives the evaluation of pollution and pollution control problems which
are unique to coal preparation, storage, and transportation. The coal
preparation industry is a mature yet changing industry and in recent years
significant achievements have been made in pollution abatement.
In focusing on the effectiveness and efficiency of coal cleaning processes
as methods of reducing the total environmental impact in the use of energy
derived from coal, this report describes the progress made on all facets
of this program during the first year of its existence. The information
derived from the studies performed will be used to evaluate the overall
desirability of expanding the use of coal cleaning as a means of mitigating
environmental impacts caused by the burning of coal.
11
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ABSTRACT
Battelle's Columbus Laboratories is performing an environmental assessment
of coal cleaning processes under Contract No. 68-02-2163 with the Industrial
Environmental Research Laboratory [Research Triangle Park (IERL/RTP), North
Carolina] of the U.S. Environmental Protection Agency (EPA). This report
describes progress on this program during the first year of work. A strong
base of engineering, ecological, pollution control, and cost data is being
established through data gathering and systems analysis efforts.
In addition to program management, three task areas have been defined.
These technically-oriented functions are: system studies, data acquisition,
and general program support.
Systems studies have specifically focused on three subtasks. The devel-
opment of information on coal cleaning process technology has been emphasized
in the first of these subtasks, while the second has been concerned primarily
with defining the technological and cost status of the control of pollutants
from coal cleaning and refuse disposal operations. The third subtask relates
to the establishment of criteria for meeting environmental goals. Substantial
progress was made on these three subtasks and early availability of draft
reports of accomplishments is anticipated. But effort on a fourth subtask
designed to acquire process data was terminated to avoid duplication of the
effort of another EPA contractor.
Data acquisition subtasks have been directed at the planning needed as
the forerunner of the anticipated environmental field testing programs. Progress
has been made in: developing and describing the overall environmental test
program, developing the rationale for selection and selecting the evaluation
sites, specifying the experimental testing techniques to be used, and developing
the master site test plan. Based on a statistical rationale, ten unique site
categories have been specified for testing; experimental techniques are based
on accepted U.S. EPA and open literature methods.
iii
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General program support has consisted of: obtaining background environ-
mental data in the vicinity of and refining a computer simulation model for
use in studying the performance of the demonstration coal cleaning facility
near Homer City, Pennsylvania; operating the coal cleaning information center;
providing support for a sulfur emissions study for the Organization for Economic
Cooperation and Development; participating in the USSR-US technical information
exchange program; and studying and evaluating physical coal cleaning as an
SC- emission control strategy. A draft report on the latter physical coal
cleaning evaluation has been submitted to the Office of Air Quality Programs
and Standards.
This first annual report consists of two volumes: Volume 1 - Executive
Summary and Volume 2 - Detailed Report. It covers the period from July 2, 1976,
through September 30, 1977.
iv
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CONTENTS
Pages
FOREWORD ii
ABSTRACT ill
ACKNOWLEDGEMENTS xi
INTRODUCTION 1
CURRENT PROCESS TECHNOLOGY BACKGROUND 4
Process Information 4
Status 8
REFERENCES 23
CURRENT ENVIRONMENTAL BACKGROUND 25
Potential Pollutants and Impacts in All Media 25
Federal and State Standards and Criteria 41
Other Regulatory Requirements 48
Occupational Health/Epidemiological Data 51
Dose/Response Data 51
Transport Models 55
REFERENCES 59
ENVIRONMENTAL OBJECTIVES DEVELOPMENT 63
Establishment of Permissible Media Concentration 63
Define Emission Goals 64
Non-Pollutant Impact Goals 64
Bioassay Criteria 65
Decision Criteria for Prioritizing Pollutants 66
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CONTENTS
(Continued)
Pages
Methodologies Being Developed 67
Source Analysis Models 69
REFERENCES 70
ENVIRONMENTAL DATA ACQUISITION 72
Existing Process Data 72
Sampling and Analytical Techniques 75
Test Development Program 83
Preoperational Environmental Monitoring 89
Conclusions 98
REFERENCES 103
CONTROL TECHNOLOGY ASSESSMENT 104
Control Systems and Disposal Option Information 104
Control Process Pollution and Impacts 138
REFERENCES 140
ENVIRONMENTAL ALTERNATIVES ANALYSIS 142
Pollutant Ranking 142
Modification of Computer Models for
Evaluating Process Technology 143
Modifications Made to Program 144
REFERENCES 151
TECHNOLOGY TRANSFER 152
Information Centers 153
vi
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CONTENTS
(Continued)
Pages
Coordination and Preparation of Monthly
and Quarterly Newsletters 156
Other Reports Issued 156
FUGURE EFFORTS 164
Current Process Technology Background 164
Current Environmental Background 164
Environmental Objectives Development 165
Environmental Data Acquisition 166
Control Technology Assessment 167
Control Technology Development Status 169
Environmental Alternatives Analysis 169
Technology Transfer 170
vii
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LIST OF TABLES
Pages
Table 1. Relationship of Organization of Battelle's
Program for Environmental Assessment of Coal
Cleaning to EACD Annual Report Categories 2
Table 2. Physical Coal Cleaning Plants Categorized
by States for 1975 9
Table 3. Preparation of Coal by Type of Equipment 10
Table 4. Generic Types of Coal Preparation Plants 11
Table 5. Sulfur Reduction by Physical Coal Cleaning 14
Table 6. Proposed Priority I Pollutants for
Coal Cleaning Processes 28
Table 7. Pollutant Effects on Vegetation 39
Table 8. Estimated Permissible Air Concentrations
for Elements Found in Coal and Coal Ash 52
Table 9. Suggested Scheme for Analytical Characterization
of Coal Cleaning Processes 78
Table 10. Classification Variables and Associated
Levels Used to Define Site Categories • 85
Table 11. Recommended Sequential Sampling Design
for Coal Cleaning Plants 87
Table 12. Prioritized Constraints Used in Specific
Site Selection Procedures 88
Table 13. Classification of Emission Control Equipment 106
Table 14. Typical Efficiency Ranges for Cyclone Collectors 109
Table 15. Dust Collector Characteristics and
Application Chart 114
Table 16. Summary of Applications for Particulate
Control Equipment 115
viii
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LIST OF TABLES
(Continued)
Pages
Table 17. Estimated Costs of Air Pollution Control
Equipment for Coal Cleaning Plants 118
Table 18. Classification of Water Treatment Technologies 120
Table 19. Estimated Costs of Water Pollution Control
Equipment for Selected 1000 TPH Coal Cleaning Plants . . . 124
Table 20. Effluent Standards for New Coal Refuse Areas 135
Table 21. Comparison of Results from Program CPSM4
with Actual Material Balance 149
ix
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LIST OF FIGURES
Pages
Figure 1. Illustration of Relationship of Elements
Selected for Priority I Pollutant List
to Those Omitted 29
Figure 2. Homer City Power Complex 90
Figure 3. Disposal Areas for Solid Refuse from Coal
Mining, Cleaning, and Burning 92
Figure 4. Liquid Refuse from Coal Mining, Cleaning, and Burning . . 93
Figure 5. Abiotic Environmental Evaluation Areas 95
Figure 6. Sampling Sites at Cleaning Plant Refuse Disposal Area . . 96
Figure 7. Water Quality Sampling Locations ... 99
Figure 8. Unit Operations Simulated 145
Figure 9. Material Balance 150
Figure 10. Coal Availability Bar Chart 160
Figure 11. Coal Availability Bar Chart 161
x
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ACKNOWLEDGEMENTS
Although this first annual report was actually written by the stated
authors, this document could not have been prepared without the completed
and continuing contributions of the numerous researchers who are involved.
These include: David P- Ambrose, Wayne E. Ballantyne, Donald P. Brown,
Ronald Clark, Barney W. Cornaby, Robert A. Ewing, Frederick K. Goodman,
Henry M. Grotta, Elton H. Hall, R. E. Heffelfinger, Robert D. Igou, Jane
H. McCreery, Seongwoo Min, David W. Neuendorf, David A. Sharp, Shirley J.
Smith, Ralph E. Thomas, Duane A. Tolle, and Bruce W. Vigon of the Battelle
staff. One of the authors, Dr. G. E. Raines of Raines Consulting, Inc.,
is a consultant to Battelle. Also, the contributions of the Program Manager,
Mr. G. Ray Smithson, Jr., are gratefully acknowledged.
This study was conducted as a part of the Battelle's Columbus Labor-
atories' ongoing program, "Environmental Assessment of Coal Cleaning Processes",
which is supported by the U.S. Environmental Protection Agency, Industrial
Environmental Research Laboratory, Research Triangle Park (IERL/RTP), North
Carolina. The advice and counsel of the EPA Project Officer, Mr. James D.
Kilgroe, and other IERL/RTP staff members were invaluable in performance of
this work.
xi
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INTRODUCTION
This is the first annual report describing activities of Battelle's
Columbus Laboratories under Contract No. 68-02-2163 for the environmental
/
assessment of coal cleaning processes. The program is organized into three
major task categories: (1) systems studies, (2) data acquisition, and
(3) general program support. The program is further divided into subtasks
which correspond to technical directives received from EPA. A special subtask
is allocated for project management.
The following subtasks were active during the year and were
designated by the three-digit numbers as indicated.
• Project Management (Oil)
Systems Studies
• Technology Overview (211)
• Detailed Process Descriptions (222)
• Process Data Acquisition (232)
• Develop Assessment Criteria (241)
Data Acquisition
• Develop Environmental Test Program (411)
• Select Evaluation Sites (421)
• Develop Experimental Techniques (431)
• Test Plan Development (451)
General Program Support
• Coal Cleaning Demo Planning (813)
• Coal Cleaning Information Center (821)
• OECD Support (831)
• US-USSR Information Exchange (841)
• Evaluation of Physical Coal Cleaning as an SO? Emission
Control Strategy (851)
The activities for these various subtasks are described in sections
of the "Executive Summary" and "Detailed Report" as indicated by Table 1.
In addition to completion of the ongoing tasks listed above, future
activities in the remaining 21 months of the contract are planned for
the following subtasks. These efforts are briefly described under "Future
Efforts".
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TABLE 1. RELATIONSHIP OF ORGANIZATION OF BATTELLE'S
FOR ENVIRONMENTAL ASSESSMENT OF COAL CLEANING
TO EACD* ANNUAL REPORT CATEGORIES
Subtask Number**^
Category in Management Summary
and Detailed Report
Systems
Studies
Data
Acquisition
General Program
Support
211 222 241 411 421 431 451 813 821 831 841 851
Process Information
Status
Schedules
Priorities for
Further Studies
Potential Pollutants and
Impacts in All Media
Federal and State Standards
and Criteria
Other Regulatory Requirements
Occupational Health/
Epidemiological Data
Dose/Response Data
Transport Models
Establishment of Permissible
Media Concentrations
Define Emission Goals
Non-Pollutant Impact Goals
Bioassay Criteria
Decision Criteria for
Prioritizing Pollutants
Methodologies Being
Developed
Source Analysis Models
Existing Data for Each
Process
Sampling and Analytical
Techniques
Test Program Development
Preoperational Environ-
mental Monitoring
MEG Pollutant List and
Recommended Additions
for Consideration
Control Systems and
Disposal Option Information
Control Process Pollution
and Impacts
Current Process Technology Back
X
X
X
X
X
'round
Current Environmental Background
s
nts
Enviroi
le
X
iment
X
il Ob
X
X
X
X
X
X
ecti-i
X
X
X
X
X
X
X
ires D
eveloi
ument
Environmental Data Acquisition
Coi
X
itroX
X
X
Technology Ass
X
X
X
X
X
X
essment
Control Technology Development Status
(no activity)
Environmental Alternatives Analysis
Pollutant Ranking
Modification of Computer
Models for Evaluating
Process Technology
Newsletter Status Reports
Information Centers
Other Reports Issued
X
X
X
Technology Transfer
X
X
X
X
X
* EPA Energy Assessment and Control Division, Research Triangle Park, N.C.
** Task 232 is utilized for input to Task 222 and, thus, is not reported separately.
2
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Systems Studies
• Pollution Control Trade-Off Studies (251)
• New Control Technologies (271)
• Revised Process Descriptions and Impact Assessments (281)
• Revised Technology Overviews (291)
Data Acquisition
• Test Support Development (441)
• Testing (461)
• Data Reporting (471)
General Program Support
(as authorized by EPA)
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CURRENT PROCESS TECHNOLOGY BACKGROUND
Current coal cleaning process technology was Investigated as part
of Subtask 211 for a technology overview study. A draft report on this
subtask, entitled "Technology Overview of Coal Cleaning Processes and
Environmental Controls", dated January, 1977, was prepared and submitted
to EPA.
The overall objective of Subtask 211 was to provide a review of
the objectives and U.S. methods for coal cleaning process technologies and
related environmental control. The technology overview report was to
provide a background against which the requirements can be established
for assessment of coal cleaning technology and the control of the associated
pollutants evolved from these processes and related activities.
The state of the art of coal preparation and related pollution
control technology were summarized. The physical and chemical properties
of coal important to coal preparation were described and the pertinent
literature on washability of many U.S. coals was compiled. A technological
review was provided for various coal preparation processes including size
reduction, screening, physical cleaning, chemical cleaning, dewatering,
drying, transportation, storage, coal handling, water handling, and
solid waste handling.
The results of the technology overview study related to coal
cleaning process technology are summarized in this section. Other results
of Subtask 211 are summarized in the sections entitled "Current Environmental
Background" and "Control Technology Assessment".
Process Information
As it comes from the mine, coal is known as run-of-mine (ROM) coal
and consists of a range of sizes from chunks to small particles mixed with some
dirt and rocks. In most cases, this ROM coal needs some degree of preparation
to meet certain market requirements as to sizes, ash, sulfur, moisture, and
heating values. Coal preparation processes as defined by this EPA study encom-
pass all activities between the mining of coal and the end use of cleaned coal.
These include coal sizing, cleaning, transportation, storage, refuse disposal,
etc.
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The principal coal-cleaning processes used today are oriented
toward product standardization and ash reduction, with increased attention
being put on sulfur reduction. Coal preparation in commercial practice is
currently limited to physical processes. In a modern coal-cleaning plant,
the coal is typically subjected to (1) size reduction and screening, (2)
separation of coal from its impurities, and (3) dewatering and drying.
Size reduction is usually accomplished by a staged operation using
a series of crushers rather than crushing to the desired size with a single
crusher. Primary breaking generally reduces the raw coal to a top size of
from 4 to 8 inches. The undersized materials are usually screened out
prior to breaking. Primary breaking is almost entirely done by the roll-
type crusher, although rotary screen-type breakers are employed to provide
rough cleaning. Secondary crushing reduces the coal to top sizes of about
1-1/2 or 1-3/4 inches, and screening crushers reduce the product from the
secondary crushers to the final top sizes from about 1 to 3/8 inch.
The extent of size reduction depends on the type of coal processed
and the desired product characteristics. It is a well known fact that more
of the impurities are liberated as the size of coal is reduced. However,
because the costs of preparation rise exponentially with the amount of fines
to be treated, there is an economic optimum in size reduction.
Coal is screened in either the wet or dry state to separate the
various size fractions resulting from the size reduction. Screens may be
stationary or moving. The screening surface may be a perforated plate, a
woven wire cloth, formed bars, or nonstationary parallel bars. By far the
most common screens are perforated plate and square-opening woven wire
screens that shake or vibrate. The screening surfaces are usually made of
high-carbon steels for larger openings and stainless steels for finer
openings to provide abrasion, corrosion, and erosion resistance.
In a modern coal cleaning plant, the crushed coal is often divided
into coarse, intermediate, and fine sizes, and separation of ash and pyrite
from the coal is then accomplished with a variety of devices for the three
individual size groupings. In coarse coal circuits, the coal is cleaned with
one or a combination of gravity separation equipment such as jigs, launders,
or heavy-medium vessels. The intermediate-size coals are usually cleaned
with concentration tables or heavy-medium cyclones. In cleaning of fine-
size coal, froth flotation or hydrocyclones are often employed.
5
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Following the wet cleaning process, the product requires dewatering
or complete drying depending on the ultimate use and transportation systems
being utilized. Moisture left in the coal decreases the combustion heat
available and also causes shipping and handling problems. Wet coal has a
tendency to adhere to bins, chutes, railroad cars, and trucks. Addition-
ally, in cold weather, wet coal freezes causing further handling problems.
Therefore, coal-water separation is an important process for the producer
as well as the buyer.
For coarse coal with particle sizes greater than 1/4 inch, the
coal can be dewatered readily by natural drainage using perforated bucket
elevators or dewatering screens. For fine coal, the watering is considerably
more difficult and costly. Some of the fine coal will pass through the
screen or bucket openings, and thus more complicated dewatering techniques
are required. In addition, fine-coal surface area per unit weight is large,
and hence the amount of moisture remaining on the surface per unit weight
of coal is also large. Moreover, fine coals tend to pack so tightly that
capillary action will hold water in the void spaces between coal particles.
Consequently, fine coals usually contain relatively high moisture after
mechanical dewatering and require thermal drying to obtain acceptable
moisture contents.
As a result of stream pollution regulations and the coal industry's
desire to improve fine coal recovery, recirculation and treatment of wash
water are integral parts of the operation of a modern coal cleaning plant.
In particular, closed water circuits have grown in popularity because they
eliminate discharge to streams, reduce make-up water, and allow for recovery
of coal. Since closing the circuit results in the build-up of slimes, it
is necessary to remove a certain portion of these fine solids. Standard
equipment generally applied in a closed water circuit consists of thickeners,
cyclones, filters, and/or solid bowl centrifuges.
The basic principles of waste water treatment are flocculation and
sedimentation. Numerous flocculation agents and a wide variety of sedi-
mentation equipment are employed for removing the suspended solids from
the washing water. Starches are probably the most commonly used flocculant
in wash water treatment. Recently, many synthetic organic flocculants
have been developed.
6
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The disposal of coal cleaning plant waste is a worldwide problem
of increasing magnitude. Coal refuse consists of waste coal, slate, carbon-
aceous and pyritic shales, and clay associated with a coal seam. It is
estimated that about 25 percent of the raw coal mined is disposed of as
waste. Coal refuse disposal involves two quite separate and distinct
materials—a coarse refuse (+28 mesh) and a fine refuse (-28 mesh). The
coarse refuse is normally disposed of in an embankment by dumping either from
an aerial tramway or from trucks. The fine refuse is normally removed
from the preparation plant water circuit as a thickener underflow and
impounded into nearby settling ponds. Mine refuse piles across valleys have
formed convenient, ready-made settling ponds for disposing of fine refuse.
Transportation of coal from the mines or preparation plants to
the point of consumption is one of the most important factors affecting coal
utilization because transportation costs frequently account for between
one-third and one-half of the delivered price of coal. Transportation
costs vary widely depending on the type of carrier, size of shipment, and
distance. Transportation modes are rail, waterway, truck, pipeline, and
belt conveyor. Often, more than one mode of transportation is used to convey
coal from the mine to the consumer.
Storage of coal is an economic necessity in coal preparation to
provide a reserve against production interruptions and also to facilitate
intermittent shipment. As production and transportation capacity are
increasing, coal cleaning plants require larger storage facilities to
•
secure the maximum utilization of coal cleaning and transportation equip-
ment. Coal is stored in huge open piles or enclosed bins and silos.
In conjunction with transportation and storage of coal, a wide
variety of material handling operations is needed. These include loading
and unloading, stacking and reclaiming, and transferring coal in a plant.
As the amounts of coal to be handled have grown, the material handling
systems have become more mechanized and equipped with more automatic and
integrated control devices.
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Status
Conventional Physical Coal Cleaning
Physical coal cleaning is a proven technology for upgrading raw
coal by physical removal of associated impurities. In the United States, there
are over 450 physical coal-cleaning plants which can handle over 400 million
tons of raw coal per year. Table 2 summarizes the status of coal-cleaning
(2)
plants operated in 1975. Some plants employ only one unit process, and
some use a series of cleaning processes. The capacity of individual plants
varies from less than 200 tons per day to more than 25,000 tons per•day.
The commercial practice of coal cleaning is currently limited to
the gravity methods together with minor application of froth flotation
methods. Table 3 summarizes the types of processes and equipment used over
(3)
the years in coal cleaning. It shows that jigging still handles the
largest portion of coal-cleaning. However, dense-medium processes and
concentrating tables are becoming more popular, and froth flotation is
starting to play an important role.
Sulfur reduction by physical cleaning varies widely. Physical
cleaning is capable of removing, on the average, about 50 percent of the
pyritic sulfur and 30 percent of total sulfur. The result depends on the
washability of coal, unit processes employed, and separating density.
In order to provide a systematic assessment of environmental
impacts, coal preparation has been classified into four levels according
to the coal sizes being washed. Coal preparation plants may be
categorized into nine generic types based on coal cleaning processes
employed. These levels of preparation and types of plants are summarized
in Table 4 and defined in more detail as follows.
• Level 1 - Crushing and Sizing
Type A: Crushing for top size control with limited
removal of coarse refuse and trash by scalping
screen and/or rotary breaker
• Level 2 - Coarse Size Coal Beneficiation
8
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TABLE 2. PHYSICAL COAL CLEANING PLANTS CATEGORIZED BY STATES FOR 1975
(2)
Estimated
Total
Coal Production
State 1000 tons
.Alabama
Arkansas
Colorado
Illinois
Indiana
Kansas
Kentucky
Maryland
Missouri
New Mexico
Ohio
Oklahoma
Pennsylvania
(Anthracite)
Pennsylvania
(Bituminous)
Tennessee
Utah
Virginia
Washington
West Virginia
Wyoming
Total
Total (Bituminous
excluding Pa.
anthracite)
21,425
670
8,168
59,251
24,922
568
146,900
2,792
5,035
9,242
44,582
2,770
5,090
81,950
9,295
6,600
36,500
3,700
110,000
23,595
603,055
597,965
Number
of
Coal-
, Cleaning
Plants
22
1
2
33
7
2
70
1
2
1
18
2
24
66
5
6
42
2
152
1
459
435
Number
of Coal Total
Cleaning Daily
Plants Capacity
for Which of
Capacity Reporting
Data Plants,
Reported tons
10
0
0
20
6
2
48
0
1
1
13
1
14
50
4
4
29
1
113
1
318
304
40,600
-
-
136,775
42,000
3,800
245,700
-
3,500
6.000
102,750
550
13,000
285,010
8,520
23,100
143,550
20,000
577,375
600
1,652,830
1,639,830
Estimated
Annual
Capacity
of
Reporting
Plants,^
1000 tons
10,150
-
-
34,195
10,500
950
61,425
-
875
1,500
25,690
140
3,250
71,255
2,130
5,775
35,890
5,000
144,345
150
413,210
409,960
Number of Plants Using Various
Cleaning Methods
Heavy
Media
Washers Jigs
8
1
2
17
2
-
43
-
-
1
6
1
21
30
1
2
26
1
104
-
266
245
10
-
-
20
5
2
27
-
2
-
11
1
4
19
1
4
15
1
55
-
177
173
Flotation Air
Units Tables
6
-
1
4
1
-
16
1
-
1
-
-
4
16
1
2
9
-
59
-
121
117
1
-
-
1
-
-
4
-
-
-
1
-
—
20
2
2
8
-
12
1
52
52
Washing
Tables
12
1
-
1
1
-
20
-
-
-
2
-
3
15
-
-
15
-
55
-
125
122
(a) The estimated annual-capacity values for the reporting plants were calculated from the daily-capacity values by
assuming an average plant operationg of 250 days per year (5 days per week for 50 weeks per year).
-------
TABLE 3. PREPARATION OF COAL BY TYPE OF EQUIPMENT
Yearly Percentage of
Clean Coal Produced
Washer Type
Jigs
Dense-medium processes
Concentrating tables
Flotation
Pneumatic
Classifiers
Launders
Combination of methods
1942
47.0
—
2.2
—
14.2
^1
y 29.6
J
7.0
1952
42.8
13.8
1.6
—
8.2
8.5
5.2
19.9
1962
50.2
25.3
11.7
1.6
6.9
2.1
2.2
__
1972
43.6
31.4
13.7
4.4
4.0
1.0
1.9
__
10
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TABLE 4. GENERIC TYPES OF COAL PREPARATION PLANTS
Level
1
2
3
3
3
4
4
4
4
Plant
Type
A
B
C
E
F
G
H
I
Coal Size and
Coarse
(3 x 3/8 in.)
CS
CS + J/DMV + MD
CS + J/DMV + MD
rc 4. T/DMV 4- NTH
CS + J/DMV + MD
CS + J/DMV + MD
CS + J/DMV + MD
CS + J/DMV + MD
CS + J/DMV + MD
Unit Operation
Medium Fine
(3/8 in x 28 M) (28 M x 0)
, ._
Cs Al
/ TYhfP 1 MT»
\ 1JP1L. 1 ML)
WT + MD HC + MD
WT + MD F + MD
DMC + MD HC + MD
DMC + MD F + MD
V
r
\
' 'f
+ TD
+ TD
+ TD
+ TD
Legend:
Level 1 - Crushing and Sizing
Level 2 - Coarse Size Coal Beneficiation
Level 3 - Medium Size Coal Beneficiation
Level 4 - Fine Size Coal Beneficiation
CS - Crushing and Sizing Devices
J - Jigs
DMV - Dense-Medium Vessels
DMC - Dense-Medium Cyclones
AT - Air Tables
WT - Wet Concentrating Tables
HC - Hydrocyclones
F - Froth Flotation Units
MD - Mechanical Dewatering Devices
TD - Thermal Dryers
11
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Type B: Type A followed, by dry screening at 3/8-
inch and wet beneficiation of plus 3/8-inch
material only with jig or dense-medium vessel.
Minus 3/8-inch material is mixed with coarse
product without washing. Simple mechanical
dewatering for plus 3/8-inch material.
• Level 3 - Medium Size Coal Beneficiation
Type C: Type B plus dry beneficiation of minus 3/8-
inch material with air table.
Type D: Type A followed by wet screening at 3/8-inch
and Type B beneficiation of plus 3/8-inch
material and wet beneficiation of minus 3/8-
inch material with concentrating table.
Type E: Same as Type ,D except that heavy-medium cyclone
is used for minus 3/8-inch material beneficiation.
• Level 4 - Fine Size Coal Beneficiation
Type F: Type D followed by wet beneficiation of minus
28 mesh material with hydrocyclones. Thermal
drying for fine coal product.
Type G: Same as Type F except that froth flotation
circuit is used for minus 28 mesh material
benef iciat ion.
Type H: Type E followed by wet beneficiation of minus
28 mesh material with hydrocyclone. Thermal
drying for fine coal product.
Type I: Same as Type H except that froth flotation
circuit is used for minus 28 mesh material
beneficiation.
Preparation practice for steam coal lies between Levels 2 and 3,
metallurgical coals are usually beneficiated through Level 4. During the
past few years, however, the coal industry has undergone significant changes.
First, steam coal prices tripled and metallurgical coal prices doubled from
1969 to 1974. This price structure has created a new environment for coal
preparation, and the increased value of coal justifies additional capital
investment in cleaning facilities to optimize yield and quality of clean
12
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coal product. Second, environmental considerations have given impetus to
the adaptation of existing coal-cleaning technology and development of new
or improved technology, particularly for the removal of sulfur from coal.
Consequently, it is anticipated that the majority of new coal-cleaning
plants built will be in Level 4 to obtain maximum ash and sulfur removal.
The sulfur reduction which could be brought about by physical
cleaning of coals from various regions of the U.S. is shown in Table 5.
These values are not based on actual results of commercial coal cleaning
but are estimated from the data of float-sink analysis by the U.S. Bureau
(A)
of Mines. ' These data indicate hypothetical enhancement of coal quality
which could be achieved by beneficiation. Actual values will vary with each
installation, reflecting coal seam characteristics, mining procedures, and
specific beneficiation processes selected.
An alternative strategy which could make greater utilization of
coal cleaning is the multi-stream coal system (MCCS) employed by the
Pennsylvania Electric Company, at Homer City, Pennsylvania. ' In the
MCCS process, the ROM coal (approximately 2.7 percent sulfur) is crushed
and cleaned in a dense-media cyclone circuit, yielding a product coal with
1.7 percent sulfur. The coal moves then to a second dense-media cyclone
circuit which produces low-sulfur coal (0.8 percent sulfur) and medium-sulfur
coal (2.2 percent sulfur). The low-sulfur coal is then used as feed for the
new generating unit to meet Federal sulfur emission regulations. The
medium-sulfur coal will be burned in existing boilers which are subject to
less stringent state emission standards.
New Physical Coal Cleaning Processes
Physical cleaning of coal in current practice can remove only a
portion of the pyritic sulfur content. The percentage that is removed by
any given technique depends on the size and distribution of pyrite grains
within the coal. In some cases, where the pyrite exists in large rela-
tively discrete crystals, a high degree of separation is easily obtained.
On the other hand, if the pyrite consists of small grains mixed intimately
through the coal matrix, separation by physical means can be extremely
difficult,
13
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TABLE 5. SULFUR REDUCTION BY PHYSICAL COAL CLEANING
(a)
Btu Recovery, %
Level 1
Beneficiation
99
Level 2
Beneficiation
95
Level 3
Beneficiation
90
Level 4
Beneficiation
85
Pyritic Sulfur
Reduction, %
Total Sulfur
Reduction, %
Ib S0_ Emission
per I06 Btu
Northern Appalachian
Southern Appalachian
Alabama
Eastern Midwest
Western Midwest
Western
U.S. Average
Northern Appalachian
Southern Appalachian
Alabama
Eastern Midwest
Western Midwest
Western
U.S. Average
Northern Appalachian
Southern Appalachian
Alabama
Eastern Midwest
Western Midwest
Western
U.S. Average
10
15
10
20
15
8
13
5
2
3
6
5
2
6
4.5
1.5
2.0
5.8
8.0
1.1
4.7
33
35
32
45
33
30
35
20
6
9
22
21
8
20
3.5
1.4
2.0
4.7
6.8
0.9
3.8
47
44
38
54
41
33
46
28
9
12
29
25
11
25
3.1
1.3
2.0
4.2
6.2
0.9
2.9
54
48
39
59
45
33
52
33
9
12
32
29
11
29
2.9
1.3
2.0
4.0
5.9
0.9
2.7
(4)
(a) Estimates by Bureau of Mines based on float-sink data for individual coal samples.
number of coal samples, not on weight of reserves represented by each coal sample.
Weightings based on
-------
A number of new techniques for physical coal cleaning have been
investigated to improve the pyritic sulfur removal. Among them are magnetic
separation, two-stage froth flotation, oil agglomeration, heavy liquid
separation, and chemical comminution. These processes are only in the experi-
mental stage and need considerably more work to determine their full potential.
A brief discussion of new processes is given in succeeding sections.
Two-Stage Froth Flotation. Single-stage froth flotation has long
been used as a beneficiation method-for fine coals usually denoted 28 mesh x 0.
This process consists of agitating the finely divided coal and mineral suspension
with small amounts of reagents in the presence of water and air. The reagents
help to form small air bubbles which collect the hydrophobic coal particles
and carry them to the surface, while the hydrophilic mineral matter is wetted
by water and drawn off as tailings.
Recently, a novel two-stage froth flotation process was developed
by the U.S. Bureau of Mines to remove pyrite from fine-size coals. In
the first stage, coal was floated with a minimum amount of frother (methyl
isobutyl carbinol) while coarse, free pyrite and other refuse are removed
as tailings. In the second stage, coal was suppressed with a coal depres-
sing agent (Aero Depressant 633), while fine-size pyrite was floated with a
pyrite collector (potassium amyl xanthate).
The two-stage froth flotation process has been demonstrated in a
half-ton-per-hour-capacity pilot plant. It is reported that negotiations
are under way to install a full-scale prototype of 12 ton/hour capacity in
an existing coal-cleaning plant. The pilot-plant data showed that up to
75 percent of pyritic sulfur could be removed from the Lower Freeport coal
(minus 35 mesh) at about 60 percent of weight recovery.
Oil Agglomeration. The use of a water-immiscible liquid, usually
hydrocarbons, to separate coal from the impurities is an extension of the
principles employed in froth flotation. The surface of coal is preferentially
wetted by the hydrocarbons while the water-wetting minerals remain suspended
15
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in water. Hence, separation of two phases takes place and produces a clean
coal containing some oil and an aqueous suspension of the refuse generally
free from combustible material.
Recently, the National Research Council of Canada developed a
spherical oil agglomeration process for cleaning coal fines in two steps:
flocculation followed by a balling step. In the flocculation stage, a
small amount of light oil (less than 5 percent) was added to a 20-30 percent
coal slurry in a high-speed agitator to form micro-agglomerates. In the
balling stage, a heavy, less expensive oil was added to a rotating pelletizer-
disc to form strong spherical balls.
It is reported that the spherical oil agglomeration process has
been incorporated into the coal fine recovery circuit of a western Canadian
preparation plant. The results of laboratory-batch experiments showed that
about 50 percent of the pyritic sulfur was removed from the Canadian coal
ground to less than 50 microns at over 90 percent Btu recovery.
High Gradient Magnetic Separation. ' A high gradient magnetic
separator utilizes electromagnets to generate a magnetic field and remove
mineral components, especially pyrite, from either an aqueous suspension of
finely ground coal or dry powder. The separator consists of a column packed
with Series 430 magnetic stainless steel wool or screens which are inserted
in the base of a solenoid magnet.
General Electric Company, in conjunction with the Massachusetts
Institute of Technology and Eastern Associated Coal, is attempting to
establish the technical feasibility of removing inorganic sulfur from dry
coal powders at commercially significant rates.
In addition, the Indiana University is currently investigating
the use of high-extraction magnetic filter for the beneficiation of coal
slurry containing fines below 200 mesh. A magnetic filter of 84-inch
diameter can process up to 100 tons of raw coal per hour.
16
-------
The utility of the process has not yet been established. Test
data from the high gradient magnetic separation of dry coal powders showed
that up to 57 percent of total sulfur could be removed from an eastern coal
(48 mesh x 0) with the magnetic field intensity of 64 kilo oersteds at the
flow velocity of 2.8 cm/sec. Laboratory tests of the Indiana University
indicated that up to 93 percent of the inorganic sulfur could be removed
from a coal slurry containing 90 percent of minus 325 mesh sizes with the
magnetic field intensity of 20 kilo oersteds, using three passes at 30-seconds
retention.
Heavy Liquid Separation. Heavy liquid separation is a practical
extension of the laboratory float-sink test. The crushed raw coal is immersed
in a static bath of a heavy liquid having a density intermediate between clean
coal and reject. The float material is recovered as clean coal product and
the sink material is rejected as refuse. The used heavy liquid is recovered
completely by draining and evaporating the product coal and the reject material.
The use of a heavy liquid for coal cleaning is not new. In 1936, a 50-ton/hr
pilot plant was built by the du Pont Company using chlorinated hydrocarbons.
However, the high costs of these heavy liquids and the toxic effects of the
vapors have prohibited du Font's commercialization of their process.
Recently, the Otisca Industries reported the development of an
anhydrous heavy liquid for gravity separation of coal. The chemical compo-
sition of their liquid is presumably a fluorocarbon, with a boiling point of
24 C, a heat of evaporation of 43.1 cal/g, a specific gravity of 1.50 at
16 C. It is claimed that their process is capable of the near theoretical
separation which can be obtained in the laboratory float-sink test. The
data showed that about 44 percent of total sulfur was removed from 4 mm x 0
size coal at 74 percent weight recovery. The misplaced material fell in the
range of 0.5 +_ 0.25 percent under normal operating conditions.
17
-------
Chemical Comminution. The chemical comminution process is
basically an improved method for pyrite liberation to enable its removal. It
involves the permeation of certain low-molecular-weight compounds throughout
the existing faults, pores, and other discontinuities in coal resulting in
the weakening and disruption of the interlayer forces. The chemical selectivity
affects the coal but not the mineral matter associated with it. The net result
is the fracture of the coal, the breakage being induced selectively along the
bedding planes, mineral constituents, and the mineral boundaries. The fragmented
coal and unaffected mineral matter can then be separated by some conventional
cleaning process. The chemicals that have been reported to have the greatest
comminution ability are ammonia and methanol.
The chemical comminution of coal with ammonia has been studied by
the Syracuse University Research Corporation since 1971. The bench-scale
studies indicate that chemical comminution is capable of liberating more
pyrite and a comparable amount of ash than mechanical crushing to same size
consistency. The float-sink test for the Upper Freeport sample showed that
96.4 percent of the pyrite was removed at 1.3 specific gravity from the
chemically comminuted coal, while 90 percent of the pyrite was removed from
coal mechanically crushed to minus 14 mesh at the same specific gravity.
Chemical Coal Cleaning Processes
The usual concept of chemical cleaning of coal involves the
treatment of coal with reagents that convert the impurities into a soluble
form, usually water soluble, which can be removed by leaching. Although
chemical cleaning can remove ash from coal, the low-ash product may not
justify the cost of the extra step. Hence, the chemical cleaning is primar-
ily directed at the removal of sulfur compounds in coal. Physically cleaned
coal may be a preferred feed to the chemical cleaning process to reduce
the chemicals and the costs.
Chemical cleaning techniques currently under development are
capable of removing up to 90-95 percent of pyritic sulfur; however, only
limited success has been reported in removing organic sulfur. Because costs
of chemical treatments after commercialization are expected to be higher
18
-------
than those of physical cleaning, chemical coal cleaning may be suitable
only for low organic sulfur coals which can be utilized without stack gas
scrubbing systems. Chemical cleaning is in the early stages of develop-
ment, and it is estimated that a commercial plant could not be put into
operation for at least 5 to 10 years. A brief discussion of chemical
coal cleaning processes is given in succeeding sections.
(12)
Meyers Process. The Meyers process of TRW is one of the most
extensively studied chemical coal cleaning processes. This process employs a
chemical leach of the coal with aqueous ferric sulfate at temperatures of
between 50 and 130 C. The reagent is selective for pyrite, removing 83-98
percent of the pyrite. The products of the reaction are dissolved ferrous
sulfate and sulfuric acid, and precipitated free sulfur. The depleted leach
solution is removed by drainage and rinsing after which it is regenerated to
ferric sulfate by air oxidation. Precipitated free sulfur is washed out with an
appropriate solvent (toluene or kerosene) or vaporized and recovered by
condensation. The leaching rate depends on the pyrite concentration, the
ratio of ferric ion to iron, temperature, and coal-particle size. It has
shown that significant amounts of As, Be, Cr, Mn, Ni, Se, and Zn were
removed along with the pyrite by the Meyers process. This process was
claimed to be economically competitive with projected costs for flue-gas
scrubbing, particularly for small installations, and a pilot plant of a 6-
ton-per-day unit is being constructed with EPA sponsorship.
(13)
Ledgemont Process. The Ledgemont process of Kennecott Copper for
removing pyrite from coal employs another hydrometallurgical technique. In
this process the pulverized coal is treated at 130 C under oxygen pressure of
300 psi. The pyrite in coal is oxidized to form iron sulfate and sulfuric acid
which are washed and neutralized with lime. The advantages claimed for this
process are that there is no need for elemental sulfur removal, no regeneration
of leachant, and almost complete removal of pyrite in two hours. Kennecott
is not actively prusuing development of the process at this time.
19
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(14)
Battelle Process. Battelle has developed an alkaline leaching
process for cleaning coal known as the Battelle Hydrothermal Coal Process. It
involves the heating of an aqueous slurry of 70 percent minus 200-mesh coal
mixed with sodium hydroxide or a mixture of sodium hydroxide and calcium
hydroxide at temperatures of 220 to 340 C in an autoclave at pressures of 350
to 2500 psi. The treated coal is separated from the leachant by centrifugation,
washed and then dried to produce a solid fuel with up to 99 percent of the
pyritic sulfur removed and up to 70 percent of the organic sulfur removed. It
was shown that a number of potentially toxic or hazardous metals were also
extracted during this treatment. The treated coal was claimed to be an
improved feedstock for gasification because it was completely noncoking and
easily gasified at low temperatures. Battelle is presently funded by EPA for
a bench-scale investigation to pursue process improvement.
PERC Process.^ ERDA Pittsburgh Energy Research Center (PERC) has
developed an air/water leaching process in which the aqueous coal slurry is
exposed to air at 392 F and 1000 psia. It is claimed that pyritic sulfur is
substantially converted to iron oxide and sulfuric acid, and it is further
assumed that as much as 60 percent of the organic sulfur is removed as sulfuric
acid. The carbon loss in the PERC process is claimed to be less severe than
in caustic leaching at elevated temperatures or in the Ledgemont process. A
continuous, bench-scale unit is now under construction for further tests on
the process.
KVB Process. The KVB process developed by KVB, Inc., consists
of oxidation of the sulfur components in dry pulverized coal with gaseous NO
followed by a caustic washing operation to solubilize and remove sulfur com-
pounds generated in the oxidation step. It claims to remove both mineral and
organic sulfur at moderate temperature (250 F) and pressures (35 psia).
Nitrogen uptake by the coal structure, however, could be a problem.
Development work on the process is continuing in the laboratory, but
currently there are no further demonstration plans.
20
-------
Magnex Process. The Magnex process developed by Hazen Research
is a totally dry process in which dry pulverized coal is exposed to iron
pentacarbonyl vapor at 380 F and 40 psia. It is claimed that the iron penta-
carbonyl selectively reacts with the pyrite and other mineral elements
enhancing their magnetic properties.
The magnetized materials are then separated from the clean coal
with use of magnetic separators. The process is limited to the removal of
mineral sulfur only, and it will require grinding to liberate pyrites from
the coal. The process has been investigated on a bench scale and currently
is under further study in a one-ton-per-day process development unit.
Schedules
As described in the previous section, numerous commercially-
sized physical coal cleaning plants are in operation (see Table 1) primarily
for reduction of the ash content. The MSCC plant ' being constructed at
Homer City, Pennsylvania, is the outstanding example of a planned commercial-
size plant using physical coal cleaning to comply with SCL standards, and
its schedule is described.
Acceptance tests for the interim configuration of the Homer City
coal cleaning plant were^successfully completed in September, 1977- This
interim plant is designed to operate at a capacity of 900 T/hr of ROM coal,
and the clean coal product is to be used for existing generating units
No. 1 and No. 2.
Acceptance tests for the final configuration of the plant are
expected to be conducted in Spring, 1978. This final plant configuration is
designed to operate at a capacity of 1200 T/hr of ROM coal. The deep-cleaned
coal product is to be used for generating unit No. 3 which is now being
constructed, and the middling coal product is to be used for units No. 1
and No. 2.
Physical coal cleaning technology is available as described.
However, chemical coal cleaning is an emerging technology. Most significant
(12)
is a pilot plant planned by TRW for the Meyers Process and funded by
21
-------
EPA. The facility will process up to 8 metric tons per day and initial
operation was planned in late June/July, 1977. The first year's supply of
coal is committed from the Martinka mine in West Virginia by American
Electric Power.
Priorities for Further Studies
Increasing demand for coal as a primary energy source combined with
the stringent regulations for sulfur dioxide emission from coal combustion
results in increased pressure to expand coal preparation operations. There
are still, however, many technical and/or economic uncertainties which
must be overcome before extensive commercialization of coal cleaning as a
method of SC>2 emission control can be realized. Major areas which require
additional research, development, and demonstration activities are as
follows.
(1) The development of improved techniques for accurately
predicting the cleanability of raw coals.
(2) The development of improved techniques for quality
control of coal cleaning processes to produce cleaned
coal of consistent sulfur content.
(3) The development of improved and economical techniques
for liberating and removing fine-size pyrite.
(4) The development of commercially viable techniques
for removal of organic sulfur.
(5) The development of improved methods and expanded
capacity for coal transportation.
(6) More complete determination of the environmental
impacts and economic costs of coal cleaning.
(7) The improvement of dewatering and drying techniques.
22
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REFERENCES FOR CURRENT PROCESS
TECHNOLOGY BACKGROUND SECTION
(pp. 1-22)
(1) Min, S., Tolle, D. A., Holoman, F. L., Grotta, H., and Minshall, C. W. ,
"Technology Overview of Coal Cleaning Processes and Environmental
Controls", draft report to U.S. EPA, Battelle's Columbus Laboratories
(January 1977).
(2) 1976 Keystone Coal Industry Manual, Directory of Mechanical Coal
Cleaning Plants and Directory of Mines, McGraw Hill, New York (1976).
(3) U.S. Bureau of Mines Mineral Yearbooks 1942, 1952, 1962, 1972,
U.S. Government Printing Office, Washington, D.C.
(4) Cavallaro, J. A., Johnston, M. T., and Deurbrouck, A. W., "Sulfur
Reduction Potential of the Coals of the United States", U.S. Bureau
of Mines, RI 8118 (1976).
(5) McConnell, J. F. , "Homer City Coal Cleaning Demonstration", presented
in "Energy and the Environment", Proceedings of the 4th National
Conference on Energy and the Environment, Cincinnati, Ohio (October
1976).
(6) Miller, K. J., "Flotation of Pyrite from Coal Pilot Plant Study",
U.S. Bureau of Mines, RI 7822 (1973), and "Coal-Pyrite Flotation",
Trans. AIME 2.513, 30 (1975).
(7) Cape, C. E., Mcllhinney, A. E., and Coleman, R. D., "Beneficiation and
Balling of Coal", Trans. AIME _247. 233 (1970), and Cape, C. E.,
Mcllhinney, A. E., Sirianni, A. F., and Puddington, I. E., "Bacterial
Oxidation in Upgrading Pyritic Coal", Can. Inst. Min. and Metall.
j>6, 88 (1973).
(8) Trindale, S. C., Howard, J. B., Kolm, H. H., and Powers, C. J.,
"Magnetic Desulfurization of Coal", Fuel 53, 178 (1974).
(9) Murray, H. H., "High Intensity Magnetic Cleaning of Bituminous Coal",
NCA-2nd Symposium on Coal Preparation, Louisville, Kentucky
(October 1976).
(10) Keller, D. V., Jr., Smith, C. D., and Burch, E. F., "Demonstration
Plant Test Results of the Otisca Process Heavy Liquid Beneficiation
of Coal", presented at the Annual SME-AIME Conference, Atlanta,
Georgia (March 1977).
(11) Datta, R. S., Howard, P. H., and Hanchett, S., "Feasibility Study of
Pre-Combustion Coal Cleaning Using Chemical Comminution", final
report, FE-1777-4, to Energy Research and Development Administration,
Syracuse Research Corporation, Syracuse, New York (November 1976).
(12) Koutsoukos, E. P., Kraft, M. L., Orsini, R. A., Meyers, R. A.,
Santy, M. J., and Van Nice, L. J., "Meyers Process Development for
Chemical Desulfurization of Coal, Vol. I", final report, EPA-600/2-
76-143a, to EPA, TRW Systems Group, Redondo Beach, California (May 1976)
23
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(13) Agarwal, J. C., Giberti, R. A., Irminger, P. F., Petrovic, L. F., and
Sareen, S. S., "Chemical Desulfurization of Coal", Min. Cong. J. ,
61 (3) 40 (1975).
(14) Stambaugh, E. P., Miller, J. F., Tarn, S. S., Chauhan, S. P., Feldmann,
H. F., Carlton, H. E., Foster, T. H., Nack, H., and Oxley, J. H.,
"Hydrothermal Process Produces Clean Fuel", Hydrocarbon Processing
54 (7) 115 (1975).
(15) Friedman, S., LaCount, R. B., and Warzuiski, R. P., "Oxidative
Desulfurization of Coal", presented in Proceedings on Desulfurization
of Coal and Coal Char, American Chemical Society, New Orleans,
Louisiana (March 1977).
(16) Diaz, A. F., and Guth, E. D., "Coal Desulfurization Process",
U.S. Patent No. 3,909,211 (September 30, 1975).
(17) Kindig, J. K., and Turner, R. L., "Process for Improving Coal",
U.S. Patent No. 3,938,966 (February 17, 1976).
24
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CURRENT ENVIRONMENTAL BACKGROUND
The development of environmental assessment criteria including
information relating to "Current Environmental Background" was initiated under
Subtask 241. A preliminary report^ ' on this subtask, dated April 8, 1977,
was prepared and submitted to EPA.
As a result of discussions with the EPA Project Officer, the scope
of this Subtask is being restricted (1) to those activities directly related
to coal cleaning, handling, transportation, and storage, and (2) to a Priority
I list of potential pollutants with approximately 75 entries.
Results of Subtask 2A1 are summarized in this section and the
following section entitled "Environmental Objectives Development".
Potential Pollutants and Impacts
in All Media
The universe of potential pollutants depends on the boundaries
selected. Initially, the universe was taken to include the combustion of
coal in coal-fired power plants and burning coal refuse piles. Under this
interpretation, the myriad of organics formed by the combustion of coal in
oxygen-deficient regimes (coking-type reactions) were included as representative
of gob-pile burning. These numbered in the hundreds; over 800 compounds have
been identified from the coking of coal. Many different pollutants have been
identified as being associated with raw coal or with some segment of the coal
industry. A number of lists from various sources, containing hundreds of
elements and compounds, have been compiled and were presented in BCL's coal
(2)
cleaning technology overview draft report. However, the original investi-
gations by others, from which these lists were generated by Battelle, were
performed by different investigators with different objectives and different
approaches, so that there are major differences in the manner and format in
which the results were presented. In some cases, the approach was mineralogical;
25
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individual minerals and classes were identified. In others, where wet
chemical analyses were performed, results were variously reported as oxides
or in some other analytical convention, or, often, on an elemental basis.
Trace element analysis results, by either emission spectrography or by spark
source mass spectrography (SSMS) , are reported as the element, giving no
indication of the chemical form(s) present.
Thus, one of the first tasks involved the reorganization and rational-
ization of the overlapping lists, particularly the organic compounds. However,
even after the rationalization of the list of organic compounds, many hundreds
remained, only a fraction of which could be represented by "type" compounds
representative of the numerous subgroups.
Re-examination of the basic problem led to the conclusion that the
boundaries could and should be narrowed, to eliminate pollutants which result
from coking-type reactions. Most of these compounds will be present in minute
quantities, some not at all, in gases from oxidizing combustion, such as are
encountered in thermal coal driers or in coal-fired power plants.
Gob-pile burning is not an intrinsic operation in coal cleaning,
rather, it is symptomatic of mismanagement of refuse piles. The simple
solution, which eliminates a need to consider these complex organic compounds,
is prevention.
The pollutants associated with the cleaning of coal are primarily
inorganic compounds associated with the ash fraction. Water will be the
principal receptor of the pollutants; operations causing major emissions of
air pollutants are infrequent in the cleaning of coal. Largest air emissions
will include fugitive dust from coal handling and transfers and particulates
and combustion products from coal driers.
As the investigation progressed, it became clear that it would be
advantageous to develop a relatively small list of pollutants of most interest
for the first-phase effort. The original goal was a list of 50 or less; as the
list was created it seemed advisable to slightly exceed this number, and the
final list contains about 75 entries.
For the first phase, a logical criterion for selection was to define
Priority I pollutants as those which already have been identified as pollutants
of concern and whose presence in finite concentrations in coal cleaning
26
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processes is known or suspected. The chemical substances on this list were
drawn from a number of sources, including;
• EPA criteria pollutants for air
• Pollutants identified by effluent guidelines for
coal mining and coal preparation
• Substances included in EPA "Quality Criteria for
Water"
• Toxic and hazardous pollutants listed by EPA
which may be associated with coal cleaning.
In addition to these specific pollutants, a number of more general
non-chemical pollutants and aggregated pollutant parameters were included in
the list. The proposed list, shown in Table 6, includes 49 elements and 23
chemical substances or aggregated pollutant parameters. The selection of
elements was based on a number of factors, including their recognition by
EPA as pollutants to be regulated, their elemental group, their abundance in
coal, and the availability of information on toxicity, abundance, fractionation
factors, etc.
The elements selected and their relationship to the rest of those
in the periodic table are shown in Figure 1; the omitted elements are shaded.
The following elemental groups, or portions thereof, were omitted:
• Hydrogen Not applicable
• Group IIIB, except lanthanum Low abundance;
which will represent the group low toxicity
• Group VIIIA, fixed gases Not applicable
• Group VIII, all precious metals Low abundance;
low toxicity
• All lanthanides, except lanthanum Low abundance;
low toxicity
• All actinides, except uranium and Not applicable
thorium
• All other radioactive elements, i.e., Not applicable;
technetium, radium low abundance
• All elements above 57, except mercury, Low abundance;
lead, uranium, and thorium little information
27
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TABLE 6. PROPOSED PRIORITY I POLLUTANTS
FOR COAL CLEANING PROCESSES
Elements
Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Bromine
Cadmium
Calcium
Carbon
Cerium
Cesium
Chlorine
Chromium
Cobalt
Copper
Fluorine
Gallium
Germanium
Indium
Iodine
Iron
Lanthanum
Lead
Lithium
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Niobium
Nitrogen
Oxygen
Phosphorus
Potassium
Rubidium
Selenium
Silicon
Sodium
Strontium
Sulfur
Tellurium
Thorium
Tin.
Titanium
Uranium
Vanadium
Zinc
Zirconium
Specific Pollutant
Limitations**
A B C D E F G
X
X XX
X XX
X X
X X
X
XXX
X
X X
X* X X
X*
X* X
X
X
X X
X X
X XX
X XXX
X
X X
X
X X
X
X
X
X
XXX
X
Specific Pollutant
Limitations**
Groupings A B C D E F
Mkalinity
Ammonia X
Cyanide X XX
Chlorides X
Nitrates X
Sulfides
Sulfates X
SO XX
NOX X X
To^al Suspended
Solids (TSS)
Total Dissolved
Solids (TDS) X
Chemical Oxygen
Demand
Total Suspended
Particulates (TSP) X X
Carbon Dioxide X
Carbon Monoxide X X
Hydrocarbons X
Photochemical
Oxidants X
Oil and Grease
Phenols X X
Organic • Sulfur
Compounds
Organic Nitrogen
Compounds
Polycyclic Organic
Materials (POM's)
Carbon Chloroform
Extract (CCE) X
G
X
X
X
X
X
X
* Column headings are defined as follows:
A. National Primary and Secondary Ambient Air Quality Standards
B. OSHA Standards for Workroom Air Contaminants
C. National Emission Standards for Hazardous Air Pollutants
D. New Stationary Source Performance Standards (Coal Preparation Plants)
E. Drinking Water Regulations (EPA and PHS)
F. EPA Toxic Pollutant Effluent Standards (Proposed)
G. EPA Water Quality Criteria (Proposed-not regulations)
** Metal fume standard.
28
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VIIIA
:!*3 gpg&g
i^
-------
While the selection rules may be somewhat arbitrary, the elements selected are
judged to include those of greatest priority. Other elements and substances
not listed are regarded as more appropriate for a lower priority. Some of the
49 elements may drop out later, on the basis of insignificant abundance or
lack of sufficient information for analysis and evaluation.
The remaining 23 entries on the proposed Priority I list comprise a
number of substances, e.g., sulfur dioxide, defined statutorily as a criteria
air pollutant, or aggregated pollutant parameters, e.g., total suspended
solids (TSS), also defined as a pollutant in effluent guidelines. Since many
pollutants of the latter type are variable and undefinable mixtures, there may
be insufficient information to permit their treatment in a rigorous fashion.
Table 5 also indicates where existing and proposed standards and
criteria are judged to have application to coal cleaning processes, based on
(3)
Cleland and Kingsbury's recent draft report of key Federal regulations.
(4)
The last column (G) indicates water quality criteria recently issued by EPA
which will achieve the status of regulations when they are ultimately adopted
by the states as part of their implementation plan.
Although the Priority I list satisfies the requirement of a manageable
list containing the important pollutants expected from coal cleaning processes,
there appeared to be a need for an even more abbreviated list suitable for
preliminary testing of some of the concepts and approaches to environmental
assessment. To meet this need, an abbreviated "short list" has been proposed,
which includes the following chemical pollutants:
Arsenic Manganese
Beryllium Selenium
Cadmium Sulfate sulfur
Iron Sulfur dioxide
Mercury Nitrate nitrogen
Lead Nitrogen oxides
This list, which includes both air and water pollutants, will be used to
evaluate chemical and physical transport models, as well as estimated emissions
and permissible concentrations.
30
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Following completion of the compilation of the data base on Priority
I pollutants, it is recommended that a Priority II list of pollutants be
selected for further consideration. These are, by definition, of lesser impor-
tance and concern, on the basis of today's knowledge of estimated environmental
concentrations and estimated permissible concentrations. Such a list may
include part or all of the pollutants initially identified as being in the
universe of potential pollutants.
Analysis of these Priority II pollutants probably will result in the
upgrading of a few to the lower end of the Priority I group, with the rest
assigned to the category of unimportant pollutants.
It will not be possible to analyze Priority II pollutants in time
for inclusion in the draft final report on Task 241 scheduled for January, 1978.
A preliminary evaluation of Priority II pollutants probably could be accom-
plished by July, 1978.
Estimation of Emission Concentrations
The various lists of potential pollutants described above identify
those pollutants which may be of concern, providing that they are present above
some yet undefined environmental concentration. Thus, the amounts of these
substances in the coal and their distribution through the coal cleaning and
utilization processes is one of the important factors in an environmental assess-
ment.
Coal cleaning offers the possibility of controlling potentially
harmful emissions resulting from the combustion of large tonnages of coal, by
removing the pollutants prior to combustion. Heretofore, attention has been
focused on sulfur removal by cleaning, with little attention paid to the minor
and trace elements. This is now changing, as evidenced by the Priority I list
of pollutants for this investigation.
In order to evaluate the effect of coal cleaning on removal of poten-
tially harmful major, minor, and trace elements in coal, it is necessary to
determine fractionation factors, i.e., the distribution of these elements from
raw coal into their respective components in cleaned coal, refuse, and effluent
31
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discharges. The fractionation factors may be estimated, in some cases from
experimental data for raw coal, cleaned coal, particulate emissions, and
refuse. When relevant experimental data are not available, it may be possible
to predict fractionation factors from theoretical considierations.
Prediction of fractionation factors for trace elements in coal is
extremely difficult because the form in which they exist in coal is unknown.
A principal source of empirical data on fractionation factors for coal cleaning
(washing) has been studies by the Illinois State Geological Survey. ' ' Where
experimental fractionation factors are absent, the approach of Zubovic is
being used. He postulated that trace metals are present in the organic phase
as chelated metal-organic complexes, with complex formation favored for metal
ions with a high ionic charge: ion radius ratio. The existence of such complex
formation is supported by experimental data.
There appears to be a similar correlation between the fractionation
factor and the ionic potential. As was shown in the April, 1977 draft report
on the development of environmental assessment criteria, fractionation factors
tend to increase as ionic potentials increase. {*•' However, in its present
state of development, the approach is crude, but it can provide approximate
ranges of fractionation factors for many trace elements.
/•ON
"Fractionation factors" are also available from Klein, et al., and
others, for the partitioning of elements upon combustion in a boiler. These
can be used to estimate losses to the atmosphere from the thermal drying of
cleaned coal. Using estimated material balances and a simple computer model,
several exploratory simulations have been performed. This work is to be
continued and expanded as more and better data become available. These values
of emission concentrations are required as input to dispersion models to permit
the calculation of ground level concentrations (GLC) for air pollutants and
surface water concentrations for water pollutants.
Environmental Impacts to Biota and Man
Pollutants from coal cleaning processes are released as airborne
gases and particulates, waterborne ions and compounds (including dissolved
and suspended substances), and elements and compounds associated with solid
refuse piles. The ecological impacts of these pollutants are broken down in
32
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the following review according to their effects on human health, aquatic
biota, terrestrial biota, and entire ecosystems.
Human Health. Many pollutants associated with coal cleaning and
burning are toxic to humans. Although air pollutants probably pose the great-
est health hazard, the quantity of these emissions can be drastically reduced
by prevention of refuse pile fires. Air pollutants, in addition to their
primary direct toxic effects, are known to cause secondary effects by aggravat-
ing existing disease conditions. However, the quantity of certain pollutants,
such as heavy metals, may also be of great concern in the water effluents,
due to the potential for leaching these toxic trace elements from coal refuse
and storage piles.
Air pollutants such as sulfur dioxide, nitrogen dioxide, and carbon
monoxide (all of which are emitted from thermal driers and burning refuse piles)
are known stressors on the cardiopulmonary system. Sulfur dioxide irritation
of the nose and throat, for example, occurs at exposure concentrations of
(9)
about 6-12 ppm by volume in air. Long-term exposures to sulfur dioxide have
been reported to result in nasopharyngitis, chronic bronchitis, and changes in
the mucosa of the upper respiratory tract. Inhalation of sulfur dioxide
causes a local reaction in the respiratory tract with histopathological changes
in the epithelium of the trachea, bronchi, and elastic lung tissue.
Mixtures of sulfur dioxide and aerosols often have a greater effect
than is seen when the two components act independently. This synergism occurs
with increased frequency in humid air as sulfur dioxide dissolves in the vapor
in the air and forms aerosols of soluble salts and acids. The tiny droplets
carry the sulfur dioxide more deeply into the respiratory tract than would
occur with sulfur dioxide alone. ' It has been shown, however, that any
synergism between sulfur dioxide and particulates or aerosols in terms of
potentiation of an irritant effect depends on the chemical nature of the
particle.
Reports are cited that verify increased rates of lower respiratory
illness resulting from exposure to nitrogen dioxide (N02) at low concentrations.
Both ozone and NCL can cause increased airway resistance with as little as
33
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1.6 ppm NO. exposure for 15 minutes. Stokinger and Coffin Indicate
that the reported acute effects of NO and/or of associated oxides of nitrogen
range from odor, nose and eye irritation, pulmonary congestion and edema, and
obliterative bronchiolitis and pneumonitis to death. Chronic pulmonary fibrosis
and emphysema have been shown to develop in persons who have undergone chronic,
intermittent exposure to N0_ in the range of 10 to 40 ppm. Henkin indicates
that changes in sensory perception are the most sensitive indicators of the
presence of NO.. Exposure to low concentrations of N0?, 0.075 ppm, may also
impair dark adaptation.
The clinically recognized acute effects resulting from the inhalation
of ozone include dislike of its pungent odor; dryness of mucous membrane of
the mouth, nose, and throat; changes in visual acuity; severe irritation of
the eyes; headaches; functional derangements of the lung; and pulmonary conges-
, , (12,13)
txon and edema.
Particulates and aerosols produce adverse health effects in humans.
Inorganic mists such as sulfuric acid produce symptoms of irritation or tickling
of the upper respiratory tract as well as sneezing and coughing. '
(14)
The chemical nature of particulates determines their toxicity.
Toxic elements such as lead, cadmium, vanadium, and nickel tend to concentrate
in the smaller, respirable particles. Besides irritation, particulate deposi-
tion can also impair oxygen transfer in the lungs. Fine particulates are capable
of adsorbing significant quantities of toxic gases such as sulfur dioxide and
hydrogen chloride, thereby leading to potentially severe synergistic effects
when inhaled.
Man requires certain nutrients in relatively large quantities for
life processes but metals are needed to a much lesser extent. Those metals
which man requires in substantial amounts and to which he has a rather wide
tolerance include iron, sodium, and potassium. Those which are required in
much smaller amounts and are narrowly tolerated include copper, manganese,
and cobalt. Many elements (e.g., Ca, Mg, K, Na, Fe, Mn, Cu, Zn, Co,
Mo, and Ni) are known micronutrients which are clearly essential for normal
biochemical functions.
Those elements which do not, on the other hand, have a known essen-
tial role in the life process and are toxic even at low levels include many
34
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of the minor and trace elements such as cadmium, mercury, lead, selenium,
and chromium. Many toxic elements (trace metals) are associated with
aerosols and particulates. Effects produced by trace metals associated
with aerosols and particulates are:
• Beryllium—irritation of the mucous membranes of the
eyes and upper respiratory tract
• Cadmium—disturbances in conditioned reflex activity
• Manganese—destruction of ganglion cells of the
basal ganglia; perivascular degeneration in the
striatum and pallidum" and to a lesser extent in
the frontal and parietal cortex
• Mercury—acute toxicity manifested by renal and
gastrointestinal changes; chronic toxicity indicated
by neurological changes (anxiety, anorexia, insomnia,
etc.)
• Arsenic—neurological symptoms such as pain in the
limbs, headache, convulsions, muscular weakness,
and loss of consciousness indicate acute toxicity.
Chronic toxicity manifested by numbness, burning,
tingling, or itching followed by gross tremors with
muscle atrophy and paralysis.
Aquatic Biota
Of the wide variety of toxic chemicals that are known to be asso-
ciated with coal and coal preparation activities, the trace metals are of
great environmental significance. Trace metals are often introduced into
aquatic ecosystems as byproducts of acid mine drainage residues. Trace metals
are highly toxic to aquatic organisms, especially fish. Some of the trace
metals and related trace elements are also highly bioaccumulative.
35
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Several investigators have reported that trace metals (e.g., cadmium,
copper, zinc) inhibit photosynthesis, respiration, and growth in various genera
of freshwater algae (e.g., Chlorella, Anabaena, Selenastrum). ' ' Some
of the aquatic macrophytes (plant life visible with the naked eye) are able to
concentrate such metals from water without deleterious effects. There are
also reports of trace metals (e.g., zinc) acting alone to stimulate growth in
aquatic plants and then acting synergistically with other metals to inhibit
(19)
aquatic plant growth.
Lead, iron, nickel, zinc, copper, cobalt, tin, manganese, cadmium,
and chromium are among the trace metals which exert toxic effects on various
(17 20-23)
freshwater invertebrates (protozoa, flatworms, mollusks, crustaceans). '
Some of the toxic effects include reproductive impairment, growth reduction,
(21)
and reduced survival times. Clubb, et al., have reported a synergism
between dissolved oxygen and cadmium toxicity in five species of stoneflies.
Cadmium toxicity was found to increase with increasing levels of dissolved
oxygen.
Manganese, zinc, and copper were found to be bioaccumulative in
freshwater mussels. Copper concentrations were highest in the digestive glands
and zinc and manganese were highest in gill tissue. The accumulation of lead
in benthic invertebrates and fishes was shown to be a function of habitat and
niche. Lead was discriminated against in food chain transfers such that detritus
feeders and herbivores contained higher lead concentrations than did carnivores.
Metal toxicity to fishes varies with pH, temperature, chemical
species, and water hardness. Some of the effects of trace metals such as
mercury, cadmium, zinc and copper on various freshwater fishes include reduc-
tion of growth, of survival times, and of reproductive capacity. Behavioral
responses, e.g., avoidance reactions, are modified in some cases under chronic
exposure to sublethal metal concentrations. '''
The drainage of acid waters from coal storage and refuse piles poses
a serious threat to the aquatic environment because of the ensuing change in
pH. Some organisms which live in waters receiving acid mine drainage are able
to survive while others are completely intolerant. Overall, the effects of acid
drainage on aquatic communities include a reduction in diversity and density
of organisms and a dominance by pollution-tolerant organisms. Recovery is
36
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sometimes shown by the establishment of communities with a large number of
species most of which are represented by relatively few individuals. Butler,
et al.,^ ' studied the effects of acid mine drainage on fish populations in
several watersheds in Pennsylvania. These authors concluded that total acidity,
pH, and probably heavy metals are all involved in the toxic action of acid
mine drainage on fish populations. Concurrent readings of a pH as high as
4.5 and a total acidity as low as 15 ppm were sufficient to account for the
complete loss of fish populations at about 90 percent of the sampling stations
which were devoid of fishes.
Some of the ways in which suspended solids affect aquatic biota
are:
(1). Mechanical or abrasive action (i.e., clogging
or irritational)
(2) Blanketing action or sedimentation
(3) Loss of light penetration
(4) Availability as a surface for growth of
microorganisms
(5) Adsorption and/or absorption of various
chemicals
(6) Change in temperature fluctuations.
These ecological effects can severely affect aquatic biota by endangering the
integrity of community structure. For example, the integrity of the community
structure of algae and protozoa could be seriously interfered with by any
reduction in the penetration of visible radiation into aquatic ecosystems (due
to increases in suspended solids) which would restrict or prohibit the growth
of photosynthetic organisms. Predator-prey relationships (i.e., zooplankton
grazing on phytoplankton) might change, resulting in abnormal increases or
decreases of individuals, thereby causing an upset in the population balance
and stability.(20)
Terrestrial Biota. Vegetation is stressed or killed by a variety
of gases and particulate matter. These pollutants may enter the leaf
directly from the air or be taken in by the roots from the soil. Foliar
markings are used by experts to determine air pollution effects on vegetation.
Treshow(25) listed four basic types of markings which are symptomatic of air
pollutants:
37
-------
(1) Necrosis and bleaching of intercostal or leaf
margins
(2) Glazing or silvering of leaf surface, particularly
the under surface
(3) Chlorosis or loss of chlorophyll
(4) Flecking or stippling on upper leaf
surface.
Table 7 gives symptoms shown by vegetation from effects of a variety of air
pollutants. These pollutants create stresses on vegetation which can cause
reduced growth or death. The effect of the pollutant may be a result of:
(1) The concentration of the pollutant under
consideration
(2) Its combined effect with other pollutants
(3) Its combined effect with other stressors
such as temperature, nutrients, light,
(25)
humidity, etc.
Pathways of the pollutants associated with coal cleaning and burning
to terrestrial animals include:
(1) Inhalation of gases, aerosols, and particulates
(2) Ingestion of contaminated water
(3) Ingestion of vegetation covered with particulates
and/or vegetation which has absorbed pollutants
from the soil
(4) Ingestion of contaminated animals
(5) Absorption of pollutants through the eyes or skin.
Caution must be used in assessing the effects of pollutants on terrestrial
animals, since much of the available information on effects involves the inves-
tigation of single pollutant effects on laboratory animals. Much more research
is needed on the synergistic effects of the combination of pollutants released
from coal cleaning and burning on terrestrial animals. '
38
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TABLE 7. POLLUTANT EFFECTS ON VEGETATION
(25)
LO
VO
Injury threshold
Pollutant
Sulfur dioxide
Ozone
Pcroxyacctyl-
ailrcitc
Nitrogen
dioxide
Hydrogen
fluoride
Ethylene
Chlorine
Ammonia
Hydrogen
chloride
Mercury
Hydrogen
Milfide
2.4-DichIoro-
phono;:yacctic
acid (2-4 D)
Sulfuric acid
Symptoms
Bleached spots, bleached areas between
veins, chlorosis; insect injury, winter find
drought conditions may show similar
markings
Fleck, stipple, bleached spotting, pig-
mentation; conifer needle tips become
brown and ncerotic
Glazing, silvering, or bronzing on lower
surface of leaves
Irregular, white or brown collapsed lesions
on intercostal tissue and near leaf margin
Tip and margin burn, dwarfing, leaf
abscission; narrow brown-red band
separates necrosic from green tissue;
fungal disease, cold and high tempera-
tures, drought, and wind may show similar
markings; suture red spot on peach fruit
Scp.il withering, leaf abnormalities; flower
dropping, and failure of loaf to open
properly; abscission; water stress may
produce similar markings
Bleaching between veins, tip and margin
burn, leaf abscission; marking often
similar to that of ozone
"Cooked" green appearance becoming
brown or green on drying; over-all
blackening on some species
Acid-type ncerotic lesion; tipburn on fir
needles; leaf margin necrosis on broad
leaves
Chlorosis and abscission; brown spotting;
yellowing of veins
Basal and marginal scorching
Scalloped margins, swollen stems, yellow-
green mottling or stippling, suture red
spot (2,4,5-T); epinaaty
Ncerotic spots on upper surface similar to
Maturity of
leaf affected
Middle-aged
most sensitive;
oldest least
sensitive
Oldest most
sensitive;
youngest
least sensitive
Youngest most
sensitive
Middle-aged
leaves most
sensitive
Youngest
leaves most
sensitive
Young leaves
recover; older
leaves do not
recover fully
Mature leaves
most sensitive
Mature leaves
most sensitive
Oldest leaves
most sensitive
Oldest leaves
most sensitive
Youngest leaves
most affected
Youngest leaves
most affected
All
Part of leaf affected ppm (vol) jig/m*
Mesophyll cells 0.3 785
Palisade or spongy 0.03 59
parenchyma in
leaves with no
palisade
Spongy cells 0.01 50
Mesophyll cells 2.5 4700
Epidermis and 0.1 0.08
mcsophyll (ppb)
cells
All 0.05 58
Epidermis and 0. 10 290
mcsophyll cells
Complete tissue ~ 20 ~ 14,000
Epidermis and ~ 5-10 •-' 11,200
mcsophyll cells
Epidermis and < 1 < 8,200
mcsophyll cells
20 28,000
Epidermis < 1 < 0,050
Ail _ -_
Sustained
exposure
8 hours
4 hours
C hours
4 hours
5 weeks
6 hours
2 hours
4 hours
2 hours
1-2 days
5 hours
2 hours
__
caustic or acidic compounds; high
humidity needed
-------
Both sulfur dioxide and sulfuric acid irritate the respiratory system.
However, levels much higher than normal air pollutant levels are required to
(27)
cause death in laboratory animals. Sulfur dioxide is absorbed in the
upper airways, and very little penetrates deep into the lungs unless it is
(25 27)
sorbed on small particulates. ' Feeding of SC^-damaged alfalfa to cows
had little effect, but swine exposed to several different levels of SCL concen-
trations showed eye irritation, salivation, nasal secretion, altered respir-
( 28)
ation, hemmorhage, emphysema, and pulmonary fibrosis.
Airborne fluorides cause more worldwide damage to domestic animals
than any other air pollutant. Fluoride intoxication of animals may result
from inhalation or ingestion of fluorine-contaminated vegetation. Among farm
animals, cattle are most susceptible to fluorosis followed in descending order
of susceptiblity by sheep, horses, swine, rabbits, and poultry. Chronic
symptoms associated with fluorisis include dental lesions, skeletal changes,
(28)
lethargy, emaciation, poor health, and sometimes poor reproductive efficiency.
Nitrogen dioxide is about four times more toxic to animals than nitric
(29)
oxide. Increasing concentrations of N09 can cause pulmonary congestion,
(25)
edema, obliterative bronchiolitis, pneumonitis, and eventual death. Concen-
(29)
trations greater than 100 ppm are lethal to most animal species.
Terrestrial animals are subjected to a variety of toxic trace elements
in the vicinity of coal burning facilities. These elements are either relatively
(26)
volatile (i.e., Be, F, As, Se, Cd, Pb, and Hg) v ' and/or they are preferentially
concentrated on the surface of fly ash particles (i.e., Be, Ca, Cr, K, Li, Mn,
Na, P, Pb, S, Tl, V, and Zn) . ' Of these elements, it is fairly well estab-
lished that As, Be, Cd, Cr, Mn, Ni, Pb, Sb, Se, Tl, V, and Zn are particularly
toxic. Effects of these toxic trace elements include organ system injury,
(26)
carcinogenicity, genetic and neonatal toxicity-, and immunological injury.
Ecosystems. Ecosystems are the basic fundamental units of "nature"
in which the organisms and nonliving environment are interrelated. These
dynamic units may be conceived and studied in a variety of sizes, such as a
small pond, a large lake, or a tract of forest. Generally, the larger and
more diverse ecosystems are more stable and more independent of adjacent
systems.
40
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Stickel^ ' has reviewed the three basic effects of pollutants on
ecosystems, as follows:
(1) Continued contamination of an area results in an
increasing loss of species. These simplified
communities are often less stable and more subject
to wide fluctuations than communities with a large
number of species.
(2) Some species are much more sensitive to a given
pollutant than other species. Thus, only the hardy,
more broadly adaptable species are able to survive.
In the case of vegetation, the larger plant species,
which have broad leaf areas, are usually more vulner-
able to pollutants. This vulnerability could ulti-
mately result in a forest being changed to a stand of
grass or sedge. Thus, animal species which require
forest habitats for survival are also lost from the
polluted region.
(3) When the larger plants die there is also a loss in
organic matter and in the total inventory of nutrient
elements held in the system. These nutrients are lost
through erosion and leaching, and are not quickly
replaced.
Although these three effects apply mainly to plant communities, they have many
parallels in animal communities.
Federal and State Standards and Criteria
One of the subtasks under Task 241 was to investigate Federal and
state regulations governing pollution resulting from activities associated
with coal cleaning, transportation, storage, and handling. Detailed results
of this study were reported in the April 8, 1977 preliminary report on the
development of environmental assessment criteria. In summary, the following
Federal Acts were determined to constitute the principal regulatory authority:
41
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• Clean Air Act Amendments of 1970*
• Federal Water Pollution Control Act Amendments of 1972
State regulations are generally written or amended to incorporate the
provisions of the Federal laws. In some cases, state regulations are more
stringent than are the Federal regulations. Whatever the case, however, states
are usually required to submit implementation plans, for approval, to the appro-
priate Federal agency outlining how Federal standards will be met, and specifying
a reasonable time frame for implementing those standards.
The major Federal regulations which are applicable to coal activities
as related to environmental pollution are concerned with air and water pollution
control. In addition, health standards for the workplace environment have been
promulgated to regulate exposure to various airborne contaminants.
Air Pollution Regulations
Federal. The U.S. Environmental Protection Agency has set primary
and secondary ambient air quality standards which regulate pollutant levels
in order to, respectively, protect human health and public welfare (property
and plant and animal life).
Most of the air pollutants associated with coal processes are gener-
ated mainly from coal combustion and include sulfur oxides, nitrogen oxides,
and total suspended particulates.
In accordance with Section III of the Clean Air Act, the U.S. Environ-
mental Protection Agency has promulgated standards for emissions from new stationary
sources. Since these standards are based on emissions, the owner/operator may
use any control system, but the standard must be achieved without the privilege
of variances or exemptions.
The promulgated Federal standards of performance for new and modified
coal preparation plants and handling facilities (e.g., barge-loading facilities)
regulate particulate emissions from those facilities processing more than 200
tons per day of bituminous coal. The standards stipulate the maximum permissible
particulate emission levels in g/dscm and percent opacity.
* These have been substantially modified by the Clean Air Act Amendments of
1977 (enacted August 7, 1977).
42
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The U.S. Environmental Protection Agency is only responsible for
setting new source emission limitations. Federal regulations require states
to develop new source review procedures thereby ensuring that new sources do
not violate national ambient air quality standards (NAAQS).
Wherever air quality is already better than NAAQS, Federal regulations
do not permit states to allow significant deterioration of the present air
quality. The U.S. EPA has established a specified increment in air quality
which cannot be exceeded by any new source or combination of new sources
within the impact area. Land use classes or zones are required to be estab-
lished which designate the amount of development allowable in certain regions.
The Mining Enforcement and Safety Administration (MESA) of the U.S.
Department of the Interior has set health standards for those individuals
working in surface work areas of underground and surface coal mines. The defini-
tion of surface coal mine and surface work areas of an underground mine includes
"surface areas of land and all structures, facilities,...used in...the work of
preparing the coal so extracted, and includes custom coal preparation facilities".
Health standards for these surface work areas, which include coal cleaning
facilities, have been set for: (1) respirable dust, and (2) any other airborne
contaminants with threshold limit values (as adopted by the American Conference
of Governmental Industrial Hygienists).
State. Although the EPA promulgates national ambient air quality
standards (NAAQS), states have the privilege of establishing more standards.
Thirty-three states and the District of Columbia have ambient air quality
standards for one or more pollutants that are more stringent than the NAAQS.
Ten of the 19 states with coal preparation plants have ambient air quality
standards (AAQS) that are more stringent than the Federal standards.
Since the concentrations of nitrogen oxides and other pollutants
other than sulfur oxides and particulates, for which there are AAQS, are only
marginally related to the quality of coal prepared or burned, emphasis has been
placed on the standards for sulfur dioxide and particulate matter (total sus-
pended particulates). Those states with more stringent AAQS are Alaska, Arizona,
43
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California, Connecticut, Colorado, Delaware, Florida, Georgia, Hawaii, Indiana,
Kentucky, Louisiana, Maine, Maryland, Minnesota, Mississippi, Missouri, Montana,
Nevada, New Hampshire, New Mexico, New York, North Carolina, North Dakota, Ohio,
Oregon, South Dakota, Tennessee, Vermont, Washington, West Virginia, Wisconsin,
and Wyoming.
States are required to develop state implementation plans (SIP's)
which, on approval by the U.S. EPA, specify how the NAAQS or their own state
standards, if more stringent, will be achieved within three years of the promul-
gation of the SIP's. The SIP's cover existing source limits and, where appli-
cable, new source limits. These plans employ different regulatory means for
controlling pollutants from fuel-burning equipment. SIP's exist for sulfur
dioxide, total suspended particulates and nitrogen dioxide.
In terms of new source performance standards, all new sources must
conform to emission limits set by the U.S. EPA, but states are required to
develop new source review procedures. Such procedures must be conducted and
ensure that all new sources constructed do not violate NAAQS even if it involves
facility resiting or a total denial of a permit to construct a facility.
Water Pollution Regulations
Federal. Federal control of water pollution sources associated with
coal production, preparation, and consumption is achieved through the issuance
of permits to each discharger which contain the limits on the effluents dis-
charged. Effluent guidelines are presently based on the best practicable con-
trol technology currently available and must be based on the best available
technology economically achievable by 1983, except where modified requirements
are in order, pursuant to Section 301(c) of the Federal Water Pollution Con-
trol Act (FWPCA). Effluent guidelines are also being issued for new sources.
These new source performance standards, as mandated by the FWPCA's Section
306, are intended to be the most stringent standards applied.
(33)
In 1976, the Environmental Protection Agency established effluent
guidelines and standards for existing coal preparation sources which are attain-
able by the application of the best practicable control technology currently
(34)
available. These regulations specified no discharge of pollutants from
44
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coal preparation plants; controlled discharges were permitted from the coal
storage, refuse storage and preparation plant ancillary area subcategory of
sources.
At the time of preparation of the draft report, proposed effluent
guidelines for existing coal preparation sources based on the best available
technology economically achievable (BAT) had been proposed, along with proposed
(35)
standards of performance for new sources.
Subsequently, revised BAT effluent guidelines for existing sources
Clf.\
have been promulgated, which combined coal preparation plants and ancillary
operations into one subcategory, eliminated the requirement of no discharge
of pollutants for coal preparation plants, and also established slightly
different limitations for plants with acidic and alkaline discharges. Final
regulations for BAT effluent limitations have not yet been promulgated.
Very recently, standards of performance for new sources have been
proposed.(37) while ambient air standards are set at the Federal level,
ambient water quality standards are primarily a state responsibility. Federal
water quality standards presently cover only public (community) water supplies.
Maximum contaminant levels in public water supplies have been set for the
following contaminants that are associated with coal and coal activities:
arsenic, barium, cadmium, chromium, fluoride, lead, mercury, nitrate, selenium,
and silver.
Federal water quality criteria have recently been revised and ex-
panded, since the issuance of Battelle's preliminary report.(1) These cri-
teria were presented in "Quality Criteria for Water".(4) while these criteria
do not have direct regulatory use, they do form the basis for judgement by
the states in implementing state water quality regulations. They are being
utilized in developing estimated permissible concentrations (EPC's) for the
pollutants listed.
State. Water pollution control enforcement is based on effluent
standards rather than stream quality, and plant outfalls must be within certain
45
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limits prescribed for each industry. State control of water pollution sources
associated with coal preparation is achieved through the issuance of permits
independently or under the National Pollutant Discharge Elimination System
(NPDES). The permits, which contain limits on the effluents discharged, are
issued to each discharger. The objective of such control systems is to achieve
or maintain specified ambient water quality standards which are primarily a
state responsibility. The Federal laws are intended to aid the achievement of
state standards. The U.S. EPA, however, retains the authority to veto state
plans.
Since Federal and state laws have the same goals, the Federal Water
Pollution Control Act Amendments (Public Law 92-500) provide for the reduction
of duplicate laws by delegating permit issuance authority to the states.
Delegation of authority takes place when a state demonstrates that it has legal
authority and resources to operate the program as envisioned by that Federal
law. The States of Colorado, Indiana, Kansas, Maryland, Missouri, Montana,
North Dakota, Ohio, Virginia, Washington, and Wyoming are delegated NPDES-issuing
states. The effluent limitations vary among the delegated and nondelegated
states.
Solid Waste Disposal Regulations
Federal. Solid wastes generated from coal preparation are generally
subject to land disposal. Federal guidelines for land disposal of solid
wastes, accepted or excluded, are nonspecific in terms of definite quantities
which can or cannot be disposed of. Pursuant to Section 211 of the amended
Solid Waste Disposal Act, the guidelines are mandatory for Federal agencies
and are recommended to state, interstate, regional and local governmental
agencies for use in their solid waste disposal activities.
All facets (from location to operation) pertaining to land disposal
sites are covered by requirements to conform to the most stringent standards
applicable to water quality established in accordance with or effective under
the provisions of the Federal Water Pollution Control Act. Leachate collection
and treatment systems are required at disposal sites where it would be necessary
to protect ground and surface water resources.
46
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Provisions of the Solid Waste Disposal Act were significantly
modified by the passage October 21, 1976, of the comprehensive Resource Conser-
vation and Recovery Act (RCRA) of 1976 (P.L. 94-580). Since from 90 days to
two years was provided for consummation of many of the actions called for by
the Act, the exact direction which the Act will take is not yet clear. Some
of the general provisions of the Act are:
• The U.S. Environmental Protection Agency has to issue
guidelines within one year for defining sanitary land-
fills as the only acceptable land disposal alternative
which can be implemented; open dumps are to be prohibited.
• Within one year EPA shall develop and publish suggested
guidelines for solid waste management.
• Within eighteen months EPA shall promulgate criteria for
identifying hazardous waste, standards for generators,
transporters, and for treatment, storage, and disposal
of hazardous wastes.
• Permit programs are to be managed by the states but under
minimum guidelines to be provided by EPA.
• Each regulation promulgated shall be reviewed and, where
necessary, revised not less frequently than every three
years.
The indications are that coal refuse (and combustion ash) will not be classified
as hazardous wastes, which would avoid the most restrictive provisions of the
Act. Due to the lengthy time involved in fully implementing the Act, the details
of its application to coal cleaning cannot yet be ascertained.
The Geological Survey of the U.S. Department of the Interior also has
established regulations for the disposal of waste from coal preparation and
handling operations on the surface of land associated with underground mining:
"The operator shall...dispose of all waste resulting
from...preparation of coal in a manner designed to mini-
mize, control, or prevent air and water pollution and
hazards of ignition and combustion".
"Mine" in the regulation is defined as underground or surface excavation and
the surface or underground support facilities that contribute directly or
47
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indirectly to coal mining, preparation, and handling. How these regulations
will interact with the RCRA provisions is uncertain.
State. A few states have solid waste disposal regulations directly
applicable to coal preparation or consumption. The various states have
general regulations covering solid waste management, solid waste disposal,
and solid waste disposal areas (landfills, snaitary landfills, etc.). Loca-
tions of these disposal areas are to be such that there is the least possi-
bility of contamination of surface or ground waters. Presumably, the pro-
visions of the Resource Conservation and Recovery Act of 1976 will allow
definitive guidelines to be drawn up by each state for the storage and dis-
posal of solid wastes, including those generated from coal preparation and
consumption.
Other Regulatory Requirements
Regulations are ever-changing, and the discussion of them in Battelle's
April, 1977 preliminary report^ is already out of date. Some of the changes
were alluded to in the previous section; further comments may be in order.
Air Pollution Regulations
The Clean Air Act Amendments of 1977, enacted August 7, 1977, have
significantly modified the Clean Air Act Amendments of 1970, as amended June,
1974; some of these modifications will interact with coal cleaning.
One of the most important is the amendment of Section 111, covering
new source standards of performance, from the previous basis of an absolute
limitation on criteria pollutants (e.g., 1.2 Ib SC»2/10 Btu) for fossil-fuel-
fired stationary sources to a combination of a maximum emission limitation and
a percentage reduction in emissions from the level which would have resulted
from the use of fuels not subject to treatment prior to combustion. Any cleaning
48
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of the fuel after extraction and prior to combustion may be credited toward
compliance with the above standards of performance.
The actual values to be achieved have not yet been specified, and
are currently under consideration to evaluate technical and economic con-
straints. There are indications that limitations on S02 may fall in the
range of a 90 percent reduction with maximum emissions not to exceed 1.2 Ib
S02/106 Btu. It is probable that a lower emission limit of 0.2 Ib S02/106
Btu below which the percentage reduction provision will not be required will
be promulgated. Although reductions in allowable emissions of NOx and particu-
lates are also probable, these should have only a minor impact on the cleaning
of coal. The revised standards of performance are to be promulgated not later
than August 7, 1978.
Depending somewhat upon the S02 regulations finally promulgated,
these amendments are likely to influence significantly the role of coal clean-
ing in the utilization of coal. They may preclude the use of coal cleaning
as the sole method of S02 control for new utility boilers. However, in some
instances, such as non-attainment areas, coal cleaning and scrubbing may be
required to meet regulations more stringent than those for New Source Per-
formance Standards.
The atmospheric emission of several hazardous air pollutants found
in coal (beryllium and mercury) is already regulated. The establishment of
regulations governing arsenic emissions is now under consideration, with a
decision anticipated early in 1978. Other hazardous pollutants under consid-
eration include polycyclic organic matter (POM) and lead, with uncertain decision
dates. Except for POM's, emissions of the other hazardous pollutants mentioned
above, in concentrations likely to be affected by the standards, are expected
to be emitted only from sources other than fossil fuel combustion.
Water Pollution Regulations
There have been no major new Federal acts affecting water pollution
since the Federal Water Pollution Control Act Amendments of 1972 (P.L. 92-500).
New regulations have, however, been proposed under this Act which will affect
(37)
coal cleaning plants. Recently proposed New Source Performance Standards would
permit the continued discharge of process wastewater from coal cleaning plants
/OCN
which recycle waste water (adopted in April, 1977 as a revision ' of the
/ O/ \
original effluent guidelines limitations ).
49
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Slightly different limitations are proposed for acidic and alkaline
discharges, in that there are no limitations on manganese for alkaline dis-
charges. Proposed limits for total iron are 3.5 and 3.0 mg/1 (daily maximum
and 30-day average, respectively). These are considerably lower than the 0
analogous 7.0 and 3.5 mg/1 limits established for existing sources.
The establishment of effluent limitations for approximately 129 toxic
pollutants is under investigation; most of these are organic compounds which
are not expected to be present at significant concentrations in effluents from
coal cleaning plants.
Similarly, nearly 100 toxic substances are being evaluated relative
to the establishment of Federal water quality criteria. If any of these are
adopted they would affect primarily state regulations. This program is not
yet sufficiently advanced to predict the nature and extent of impacts upon coal
cleaning.
Solid Waste Disposal Regulations
A number of the components of the Resource Conservation and Recovery
Act of 1976 (RCRA) will affect coal cleaning operations, in ways not yet deter-
minable, since up to a couple of years will be required to fully implement
the provisions of the Act. Like its predecessor, the Solid Waste Disposal
Act, RCRA will leave the promulgation of governing regulations and their
enforcement to the individual states; there will not be specific Federal limi-
tations. The Federal role is to consist of financial and technical assistance
and leadership in the development, demonstration, and application of new and
improved methods of waste management.
As noted in the previous section, the U.S. EPA is mandated to develop,
within one year (i.e., by October 21, 1977) criteria for sanitary landfills,
and suggested guidelines for solid waste management. Within eighteen months
numerous criteria for identifying, transporting, treatment, and disposal of
hazardous wastes are to be promulgated. Criteria for defining hazardous wastes
are now under development but have not yet been published.
50
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Section 8002 of the Act calls for a detailed and comprehensive study
on solid wastes from active and abandoned surface and underground mines,
the scope of which will presumably include coal preparation. The report of
the study (no publication date is specified) shall include recommendations
for Federal and non-Federal actions concerning environmental effects. The
findings of this study may influence disposal procedures for coal refuse.
Occupational Health/Epidemiological Data
In assessing the potential health effects of toxic pollutants,
occupational health and epidemiolo'gical data are summarized in the form of
Threshold Limit Values (TLV's) for acute short term exposure to those major
and minor elements which are found in coal and coal ash. Since TLV's are
one of the best sources of toxicological data for humans in regard to
industrial pollutants in air, they were used in the calculation of estimated
permissible air concentrations which will not produce harmful effects as a
result of continuous long term exposure. The TLV's have been developed by
(38)
the American Conference of Governmental Industrial Hygienists and are
based on animal toxicology data and on measured effects produced on humans
working in a specific atmosphere. No attempt has been made to summarize
any other industry-related health or epidemiological literature.
TLV's were found for only 37 of the 80 elements known to occur in
coal and coal ash (Table 8) . These values permitted the calculation of esti-
mated permissible concentrations (EPC's) in air for those 37 elements using the
(39)
formula developed by Handy and Schindler. The use of the EPC values in
determining the need for control development is described later in this report.
Dose/Response Data
Dose/response data for use in calculating estimated permissible water
concentrations (EPC for water) were obtained from the National Institute for
Occupational Safety and Health (NIOSH) registry, ' which lists the toxic
effects of a large number of chemical substances. In order to calculate the
(39)
EPC for water using the formula developed by Handy and Schindler , it was
51
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TABLE 8. ESTIMATED PERMISSIBLE AIR CONCENTRATIONS
FOR ELEMENTS FOUND IN COAL AND COAL ASH
Elements Found
in Coal or Coal
Ash
TLV
mg/nf
(a)
Estimated
Permissible (jj)
Concentration
Carcinogenic
or Teratogenic
Elements
Major Elements
Aluminum
Calcium
Carbon (Black)
Hydrogen
Iron (Soluble salts)
Magnesium
Nitrogen
Oxygen
Potassium
Silicon
Sodium
Sulfur
3.5
1.0
8.33 x 10~3
2.38 x 10~3
Minor and Trace Elements
Antimony 0.5
Arsenic 0.5
Barium (Soluble compounds) 0.5
Beryllium 0.002
Bismuth
Boron
Bromine 0.7
Cadmium 0.05
Cerium
Cesium —
Chlorine 3
Chromium (Salts) 0.5
Cobalt (Metal dust & fumes) 0.1
Copper (Fume) 0.2
Dysprosium -
Erbium
Europium -
Fluorine 2
Gadolinium -
Gallium
Germanium -
1.19 x 10
1.19 x 10
1.19 x 10
4.76 x 10
-3
-3
-3
-6
1.67 x 10
0.12 x 10
-3
-3
7.14 x 10
1.19 x 10
0.24 x 10
0.48 x 10
-3
-3
-3
-3
4.76 x 10
-3
Car.
Car.
Car.
52
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TABLE 8. (Continued)
Elements Found
in Coal or Coal TLv'*'
Ash mg/m
Estimated
Permissible (b) Carcinogenic
Concentration , or Teratogenic
mg/nH Elements'0'
Minor and Trace Elements (continued)
Gold
Hafnium
Holmium
Indium
Iodine
Iridium
Lanthanum
Lead
Lithium
Lutetium
Manganese
Mercury
Molybdenum (Soluble comp.)
Neodymium
Nickel
Niobium
Osmium
Palladium
Phosphorus
Platinum (Soluble salts)
Polonium
Praeseodymium
Radium
Rhenium
Rhodium (Soluble salts)
Rubidium
Ruthenium
Samarium
Scandium
Selenium
Silver
Strontium
Tantalum
Tellurium
Terbium
Thallium (Soluble comp.)
Thorium
Thulium
Tin (Organic compounds)
_
0.5
—
_
1
-
_
0.15
0.025
—
5.0
0.05
5.0
-
1.0
-
0.002
_
0.1
0.002
-
-
-
_
0.001
-
-
-
-
0.2
0.01
-
5.0
0.1
—
0.1
-
-
0.1
^^
1.19 x 10~3
-
_
2.38 x 10~3
-
*y
0.36 x 10':? PVPVo: Car.
0.06 x 10 J *Tgr.
J-J-.y x JLU
0.12 x 10 -
11.9 x 10 ~J
~ _•?
2.38 Y 10 Car.
-6
4.76 x 10 °
„ PdCl9: Car.
0.24 x 10"^
4.76 x 10
-
-
-
z.jo x lu RhCl3: Car.
—
-
-
-3
0.48 x 10 ;?
0.02 x 10
~ -7
11.9 x 10 J
0.24 x 10"J
o
0.24 x ID""3
-
~ _7
0.24 x 10
53
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TABLE 8. (Continued)
Elements Found
in Coal or Coal
Ash
TLV
(a)
rag/m"
Estimated
Permissible
Concentration
mg/m3
Carcinogenic
or Teratogenic
Elements(°)
Minor and Trace Elements (continued)
Titanium
Tungsten (Soluble comp.) 1.0
Uranium 0.2
Vanadium (Fume) 0.05
Ytterbium
Yttrium 1.0
Zinc 1.0
Zirconium 5.0
2.38 x 10
0.48 x 10
0.12 x 10
2.38 x 10
2.38 x 10
11.9 x 10
-3
-3
-3
—3
i
-3
(a) Threshold Limit Values from American Conference Governmental Industrial
Hygienists for short term (acute) exposures.(38)
(b) Estimated Permissible Concentrations for continuous long term (chronic)
exposure computed by formula: EPC = 2.38 x 10~3 x TLV, as by Handy and
Schindler.(3^)
(c) From NIOSH Registry (Fairchild) .
54
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necessary to know either the LD5Q* or WIQ** value for oral ingestion of a
given pollutant by rats. However, these values were available for only 3 of
the 80 elements (antimony, cobalt, and indium) known to occur in coal or coal
ash which were reviewed to calculate permissible air concentrations.
Obviously, formulae for calculation of an EPC will have to be modified
to use other types of dose/response data, if an EPC is desired for all of the
potential pollutants from coal cleaning processes. This effort has been
initiated at Battelle and is discussed in a later section of this report.
However, for several pollutants known to occur in coal there are no dose/
response data in the NIOSH registry. In these cases, the dose/response
value for such an element can only be approximated by extrapolation from known
values for elements with similar chemical behavior.
Some additional dose/response data were reviewed during an analysis
of the ecological effects of pollutants from coal cleaning. The four major
headings considered in this review were human health, aquatic biota, terrestrial
biota, and ecosystems. Although the primary emphasis was on effects, some
information on doses causing these effects were reviewed and are presented in
another section of this report.
Transport Models
Pollutants emitted from coal cleaning processes can both accumulate
and disperse, in both a physical and a biological sense, depending upon the
characteristics of the pollutant and the environmental compartment. Activity
was initiated recently to develop simplified models for both the physical and
biological transport of key pollutants. These key pollutants are various
forms of sulfur, nitrogen, manganese, arsenic, cadmium, mercury, lead, iron,
beryllium, and selenium. These ten elements are all on the Priority I list
and are very significant. Application to other elements on the Priority I
list is postponed pending the outcome of this activity. The approaches being
undertaken are briefly described in the following.
* LD,_0 - Lethal Dose Fifty. The calculated dose of a pollutant which can be
expected to cause the death of 50 percent of an experimental animal
species population by any route other than inhalation. ^)
** LDLQ - Lethal Dose Low. The lowest dose of a pollutant, other than LD ,
reported to have caused the death of humans or animals by any route
other than inhalation over any time period and by any number of
individual portions. (40)
55
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Atmospheric Transport Models
The concentration of key pollutants in the flue gas and the thermal
drier atmospheric discharge will provide input for calculations of atmospheric
dispersion to yield ground level concentrations. The basic purpose of the
dispersion calculation is to provide an estimate of the dilution factor which,
when divided into the stack emission concentrations, will yield ground level
concentration.
Two basic models are required, depending on whether the pollutant is
associated with large or small particles, where 100 microns is a typical dividing
point. Large particles tend to deposit on surfaces close-in such that the air
concentration is depleted as distance from the stack increases. The concen-
tration of smaller particles is reduced only by dispersion.
Simplified dispersion models, as typified by that presented by Turner
are available to consider stack height and diameter, stack gas temperature and
exit velocity, and ambient air temperature and wind speed. Calculations would
be performed for different weather categories. Multiple sources can be consid-
ered to include the effects of more than one stack if distance between stacks
is large enough to merit this refinement.
The large particle deposition model requires only the deposition
factor, wind speed, and effective stack height. Deposition factors are avail-
able in the literature and various wind speeds of interest will be used.
Output consists of ground level concentrations and deposition rates
as a function of position (usually distance downwind) for pollutants associated
with small particles and large particles, respectively.
Aquatic Transport Models
For the estimation of surface water concentrations, the concentrations
of pollutants and the flows of waste water discharges are required as input.
Emission sources to be considered will include the waste water discharge from
coal cleaning, runoff and percolation from coal and refuse storage piles, as
56
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well as from ash ponds at coal cleaning plants and from coal storage piles at
user plants.
Sedimentation in settling basins can be allowed for by use of deposi-
tion coefficients, leaving a concentration in the water column. This water is
then further diluted by dispersion and additional sedimentation in streams, etc.
Simplified dispersion models using point sources of pollutants will be used.
These models provide a correlation of dispersion coefficient with flow velocity
and stream configuration so that reasonable approximations for surface water
concentrations associated either with a specific facility or with a generalized
case can be calculated for average flows, low flows, and high flows. USGS flow
data, precipitation data, and watershed areas can be used for estimates of flow
velocities at various flow stages of interest. Sedimentation is incorporated
by the use of deposition factors relating sedimentation rate to concentration
of the pollutant in the water body. Output will consist of sedimentation rate
and concentration in water as a function of position (normally distance down-
stream) for each case. Cases of interest will include various flow stages anti-
cipated.
Transport Through Porous Media
The leaching of key pollutants from coal and refuse piles and other
sources will provide an additional source of water pollution. Water flow,
permeability, and leachability data are needed to develop a model. Simple one-
dimensional column models are anticipated. Flow of water through a bed of soil
or other similar porous materials will leach pollutants from the bed. These
overall leaching rates can be estimated using simplified mass transfer models.
Cases of interest may include coal piles, refuse piles, pond bottoms, etc.
Ecological Transport
After a pollutant reaches the biological environment (animals and
plants), a variety of metabolic processes can alter the concentration and
form of the pollutant before it reaches the site within the body where it has
an effect and/or before a pollutant-carrying organism is eaten by an animal
(including man). Thus, models are needed to estimate the transport or redis-
57
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tribution and fate of pollutants within an ecosystem. Simplified linear
compartmental models with transfer from one compartment to another governed by
a transfer coefficient will be used. A hypothetical temperate deciduous forest
ecosystem (typically found in northern Appalachian and other regions) will be
the case of most emphasis. The ecosystem will be divided into terrestrial and
aquatic components, with functional groups being specific for each component
(i.e., primary producers, herbivores, omnivores, carnivores, and decomposers).
Output from the physical models (e.g., ground level and water concen-
trations) as well as mode of entry into the system and the chemical form of the
pollutants are needed as input.
Approach
Literature is currently being searched for specific data on the
physical and biological transport of the key pollutants. Simplified model runs
using estimated emission concentrations for the key pollutants from hypothetical
Type B and Type I coal cleaning plants will be performed. This output will assist
in the interpretation of environmental impact of such facilities and serve as
trial runs for later more extensive analysis.
58
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REFERENCES FOR CURRENT ENVIRONMENTAL
BACKGROUND SECTION
(pp. 25-58)
(1) Ewing, R.A. , D. A. Tolle, S. Min, G. E. Raines, and V. L. Holoman,
"Development of Environmental Assessment Criteria", Draft Report to
U.S. Environmental Protection Agency, Battelle's Columbus Laboratories,
April 8, 1977, 46 pp.
(2) Min, S. , D. A. Tolle, V. L. Holoman, H. Grotta, and C. W. Minshall,
"Technology Overview of Coal Cleaning Processes and Environmental
Controls", Draft Report to U.S. Environmental Protection Agency,
Battelle's Columbus Laboratories (January, 1977).
(3) Cleland, J.G. and G. L. Kingsbury, "Summary of Key Federal Regulations
and Criteria fo- Multimedia Environmental Control", Draft Report to
U.S. Environmental Protection Agency, Research Triangle Institute,
(June 1977) 132 pp + Appendix.
(4) U.S. Environmental Protection Agency, "Quality Criteria for Water",
EPA 440/9-76-023, U.S. Environmental Protection Agency, Washington, D.C.,
501 pp (1976).
(5) Ruch, R. R., H. J. Gluskoter, and N. F. Shimp, "Occurrence and Distri-
bution of Potentially Volatile Trace Elements in Coal: A Final Report",
Environmental Geology Notes No. 72, 111. State Geological Survey, Urbana,
Illinois, (August 1974), pp 41-50.
(6) Gluskoter, H. J., R. R. Ruch, W. G. Miller, R. A. Cahill, G. B. Dreher,
and J. K. Kuhn, "Trace Elements in Coal", EPA-600/7-77-064, Industrial
Environmental Research Laboratory, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina (1977) 163 pp.
(7) Zubovic, P., "Physiochemical Properties of Certain Elements as Controlling
Factors in Their Distribution in Coal", in Coal Science, Ed. by R. F.
Gould, Advances in Chemistry Series, No. 35, American Chemical Society,
Washington, D.C. (1966).
(8) Klein, D. H., A. W. Andren, J. A. Carter, J. F. Emergy, C. Feldman, W.
Fulkerson, W. S. Lyon, J. C. Ogle, Y. Talmi, R. I. Van Hook, and N.
Bolton, "Pathways of Thirty-Seven Trace Elements Through Coal-Fired
Power Plant", Environmental Science and Technology, £ (10) 973-9 (1975).
(9) Severs, R. K., "Air Pollution and Health", Texas Reports on Biology and
Medicine, _33 (1), p 45-83 (1975).
(10) Bustueva, K. A., "Health Effects of Sulfur Dioxide and Sulfuric Acid
Aerosols", International Conference on Environmental Sensing and Assessment,
Volume I, A Joint Conference Comprising the International Symposium on
Environmental Monitoring, Las Vegas, Nevada (September, 1975), pp 1-3.
59
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REFERENCES (Continued)
(11) Clinical Implications of Air Pollution Research, Edited by A. J. Finkel
and W. C. Duel, Publishing Sciences Group, Inc., Acton, Massachusetts
(1976), "Effects of Vapor Phase Pollutants on Nervous System and Sensory
Function" (R. I. Henkin), pp 193-216.
(12) Air Pollution, Volume I, Edited by A. C. Stern, Second Edition, Academic
Press, New York (1968), "Biologic Effects of Air Pollutants", (H. E.
Stokinger and D. L. Coffin), pp 445-546.
(13) Clinical Implications of Air Pollution Research, Edited by A. J. Finkel
and W. C. Duel, Publishing Sciences Group, Inc., Acton, Massachusetts
(1976), "The Effect of Ozone on Brain Function" (B. L. Johnson, J. G.
Orthoefer, T. R. Lewis, and C. Xintaras), pp 233-244.
(14) Fennelly, P. F., "Primary and Secondary Particulates as Pollutants. A
Literature Review", Journal of the Air Pollution Control Association,
25^ (7), 697-704 (1975).
(15) Pier, S. M. , "The Role of Heavy Metals in Human Health", Texas Reports
on Biology and Medicine, 33 (1), 85-106 (1975).
(16) Leland, H. V., E. D. Copenhaver, and D. J. Wilkes, "Heavy Metals and
Other Trace Elements", Journal Water Pollution Control Federation, 47
(6), 1635-1656 (1975).
(17) Leland, H. V., D. J. Wilkes, and E. D. Copenhaver, "Heavy Metals and
Related Trace Elements", Journal Water Pollution Control Federation,
J48 (6), 1459-1486 (1976).
(18) Malanchuk, J. L. and G. K. Gruendling, "Toxicity of Lead Nitrate to
Algae", Water, Air and Soil Pollution, £ (2), 181-190 (1973).
(19) Leland, H. V., E. D. Copenhaver, and L. S. Corrill, "Heavy Metals and
Other Trace Elements", Journal Water Pollution Control Federation, 46
(6), 1452-1476 (1974). ~~
(20) Pollution Ecology of Freshwater Invertebrates, Edited by C. W. Hart, Jr.
and S. L. H. Fuller, Academic Press, Inc., New York (1974), 389 pp.
(21) Clubb, R. W., A. R. Gaufin, and J. L. Lords, "Synergism Between Dissolved
Oxygen and Cadmium Toxicity in Five Species of Aquatic Insects", Environ-
mental Research, 9_ (3), 285-289 (1975).
(22) Clubb, R. W., A. R. Gaufin, and J. L. Lords, "Acute Cadmium Toxicity
Studies Upon Nine Species of Aquatic Insects", Environmental Research,
.9 (3), 332-341 (1975).
(23) Hubschman, J. H., "Effects of Copper on the Crayfish Orconectes rusticus
(Girard). I. Acute Toxicity", Crustaceana, 12, 33-42 (1967).
60
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REFERENCES (Continued)
(24) Butler, R. L., E. L. Cooper, J. K. Crawford, D. C. Hales, W. G. Kimmel,
and C. C. Wagner, "Fish and Food Organisms in Acid Mine Waters of
Pennsylvania", EPA-R3-73-032, from The Pennsylvania State University
to U.S. Environmental Protection Agency, Office of Research and Monitoring
(February, 1973), "The Effects of Acid Mine Drainage on Fish Populations"
(E. L. Cooper and C. C. Wagner), pp 73-124.
(25) Stern, A. C., H. C. Wohlers, R. W. Boubel, and W. P. Lowry, Fundamentals
of Air Pollution, Academic Press, Inc., New York (1973), Chapter 10,
pp 112-126.
(26) Trace Elements in Fuel, Edited by S. P- Babu, Advances in Chemistry
Series 141, American Chemical Society, Washington (1975), "Trace Element
Emissions: Aspects of Environmental Toxicology" (E. Piperno), pp 192-209.
(27) U.S. Department of Health, Education, and Welfare, "Air Quality Criteria
for Sulfur Oxides", AP-50, National Air Pollution Control Administration,
Washington (1970).
(28) Lillie, R. J., "Air Pollutants Affecting the Performance of Domestic
Animals: A Literature Review", Agricultural Handbook No. 380, U.S.
Department of Agriculture, Washington (1972), 109 pp.
(29) U.S. Department of Health, Education and Welfare, "Air Quality Criteria
for Nitrogen Oxides", AP-84, National Air Pollution Control Administration,
Washington (1970).
(30) Linton, R. W., A. Loh, and D. F. S. Natusch, "Surface Predominance of
Trace Elements in Airborne Particles", Science, 191, 852-854 (1976).
(31) Odum, E. P., Ecology, Holt, Reinehart and Winston, New York (1963), 152 pp.
(32) Ecological Toxicology Research; Effects of Heavy Metal and Organohalogen
Compounds, Edited by A. D. Mclntyre and C. F. Mills, Plenum Press, New
York (1975), "Some Effects of Pollutants in Terrestrial Ecosystems",
(W. H. Stickel), pp 25-74.
(33) U.S. Environmental Protection Agency, "Coal Mining Point Source Category,
Effluent Guidelines and Standards for Existing Sources", 40 CFR, Part 434,
Federal Register, 41 (94), 19832-19840, May 13, 1976.
(34) U.S. Environmental Protection Agency, Code of Federal Regulations, 4jO_
Protection of Environment, Revised as of July 1, 1976, Office of the
Federal Register, National Archives and Records Service, General Services
Administration, Washington, D.C. (1976), Part 434, "Coal Mining Point
Source Category", pp 662-677-
(35) U.S. Environmental Protection Agency, "Coal Mining Point Source Category,
Effluent Guidelines and Standards for Existing Sources", (Proposed)
40 CRF, Part 434, Federal Register, 41^ (94), 19841-19843 (1976).
61
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REFERENCES (Continued)
(36) U.S. Environmental Protection Agency, "Coal Mining Point Source Category,
Effluent Guidelines and Standards for Existing Sources", 40 CFR, Part
434, Federal Register, 42 (80), 21380-21390, April 26, 1977.
(37) U.S. Environmental Protection Agency, "Coal Mining Point Source Category"
Standards of Performance for New Sources", (Proposed) 40 CFR, Part 434,
Federal Register, _42_ (181), 46932-43938, September 19, 1977.
(38) American Conference of Governmental Industrial Hygienists, "TLV's,
Threshold Limit Values for Chemical Substances in Workroom Air Adopted
by ACGIH for 1976", Cincinnati, Ohio (1976), 94 pp.
(39) Handy, R. and A. Schindler, "Estimation of Permissible Concentrations of
Pollutants for Continuous Exposure", EPA-600/2-76-155, U.S. Environmental
Protection Agency, Research Triangle Park, N.C. (June, 1976), 136 pp.
(40) Fairchild, E. J., "Registry of Toxic Effects of Chemical Substances",
1976 Edition, National Institute for Occupational Safety and Health,
U.S. Department of Health, Education, and Welfare, Rockville, Maryland
(June, 1976), 1245 pp.
(41) Turner, D. B., "Workbook of Atmospheric Dispersion Estimates", McGraw-Hill
Publishing Company, New York, N.Y. (1970.
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ENVIRONMENTAL OBJECTIVES DEVELOPMENT
The development of environmental objectives is being undertaken as
part of Subtask 241. Results of Subtask 241 are summarized in this section
and the previous section entitled "Current Environmental Background".
Establishment of Permissible Media Concentrations
Establishment of permissible media concentrations of pollutants is
needed for pollution control development guidance, e.g., for setting
pollutant emission goals. Pollutant emission goals can, of course, be
set on the basis of best practicable technology, but from a health/ecological
viewpoint, such standards have the potential of being either too lax or
unnecessarily restrictive.
In view of the state of the art, which is still in the class of an
emerging technology, the permissible media concentrations are designated as
"estimated permissible concentrations" (EPC's), and they are regarded only
as estimates, subject to later revision as more data become available.
Since a multimedia approach is being taken to the environmental
assessment of coal cleaning, estimated permissible concentrations are needed
for all three media—air, water, and land, and these will be integral parts
of the multimedia environmental goals (MEG's), which are to be established.
EPC's will be especially germane for the homogenous media air and water,
which man and biota utilize directly. Because of the heterogenous nature of
soils, and the fact that, normally, there must be at least one transfer before
a soil pollutant impacts man, determination of EPC's for soil will prove to
be a difficult task.
The establishment of EPC's is recognized as a critical area central
to the entire environmental assessment. Unfortunately, there is no accepted
method for setting EPC's. A number of approaches have been suggested, based
on various manipulations of TLV, LD^Q, 1->T),Q values, etc. Many of the original
experimental data are in a form not directly usable, and methods for inter-
conversion and extrapolation are lacking. For these and other reasons, the
methods used have not been rigorous, and without exception, are open to
criticism on one or more counts.
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Early in the BCL program some attempts were made to compile EPC's
for air and water, (1) using basically the approach of Handy and Schindler.^'
These attempts were subsequently abandoned (a) to avoid duplicating the effort
which Research Triangle Institute is undertaking to estimate MEG's for several
hundred compounds, using available data and correlations, and, (b) because it
was deemed more fruitful for BCL to investigate and develop, if possible,
improved methodologies for deriving EPC's from health/ecological data. These
efforts are discussed in a later section on "Methodologies Being Developed".
Define Emission Goals
As noted in the preceding section, emission goals can be set on the
basis of health/ecological impacts or upon the basis of available pollution
control technology. Data for the first method are still being awaited, and
will depend upon the prior establishment of permissible environmental concen-
trations.
Preliminary data for pollution control technology capabilities and
costs have been assembled under Subtask 222, and a preliminary report has
recently been issued. However, more comprehensive data on coal character-
istics and coal cleaning process parameters will be needed before technology
related emission goals can be set with confidence; it would be premature to
attempt this at the present time.
Non-Pollutant Impact Goals
No work is in progress under the coal cleaning program on nonpollutant
impact goals. However, Battelle is working on establishing EPC's (and MEG's)
for several non-chemical pollutants and non-pollutant factors under Contract
(4)
No. 68-02-2138 for assessment of the environmental impact of fluidized-bed
combustion processes; some of the findings of this investigation may also be
applicable to coal cleaning where the same pollutants or factors are involved.
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Bioassay Criteria
Normal toxicological data (e.g., TLV's and LDso's) form the basis
for establishing permissible concentrations in air and water media for indi-
vidual substances. However, these data do not provide a basis for accounting
for synergistic and antagonistic interactions between pollutants in complex
mixtures, such as are encountered in effluents from coal cleaning and other
energy processes. To better evaluate the characteristics of such complex
mixtures, a new bioassay protocol is being developed under the EPA/ERL
Fluidized-Bed Combustion Program (Contract No. 68-02-2138). This protocol
may be used to assess the relative toxicity of an effluent by some combina-
tion of nine biological tests. Three of the nine biological tests (microbial
mutagenicity, cytotoxicity, and rodent acute toxicity) are designed to address
potential human health effects. The other six biological tests for ecological
toxicity assessment are as follows:
• freshwater algal assay
• acute static bioassays with freshwater fish and Daphnia
• bioassay with unicellular marine algae
• static bioassays with marine animals
• stress ethylene plant response
• soil-litter microcosm tests.
These tests provide a direct measure of toxicity and mutagenicity for
which there are few available data.
This bioassay method will be utilized for the coal cleaning program
to assess samples from test sites. Its use will also be considered in the
development of estimated permissible environmental concentrations and emission
goals.
The Level 1 screening techniques described in the bioassay proce-
dures manual^) are recommended by the Industrial Environmental Research
Laboratory (IERL-RTP) as part of a framework for prioritizing waste streams
according to their relative toxicity. The biological screening techniques
are designed to complement the chemical and physical procedures described
in another IERL-RTP manual by Hamersma, et al.(6).
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Results of these biological screening tests should be considered along
with the results from chemical and physical procedures to prioritize effluent
streams for more detailed (Level 2 or 3) environmental assessments.
Decision Criteria for Prioritizing Pollutants
A simple but logical basis for evaluating the importance of a pollutant
is to compare the concentration in which it is present in the environment to
the maximum concentration which presents no hazard to man or environmental
biota on a continuous long-term basis.
The environmental concentration is a function of the quantity of
pollutant emitted from the source, the extent of its dispersion or transforma-
tion in the environment, and the degree of transfer between compartments. The
environmental concentration of a pollutant may be defined in several ways. For
an air pollutant it may be the ground level concentration (GLC) associated with
a given pollutant concentration emitted from a stack. The corresponding aqueous
concentration might be the surface water concentration (SWC) reached at the
edge of the discharge mixing zone. In order to calculate either of the above
environmental concentrations, site-specific information on the physical situ-
ation must be known or assumed in order to apply the appropriate dilution factors.
The ratio of the estimated environmental concentration to the estimated
permissible concentration can serve as the basis of a rating technique for
prioritizing sources, pollutants, and emission or control problems, and this
concept is incorporated into the source analysis model (SAM) approach being
investigated by another contractor. Very preliminary attempts to apply the
concept to the coal cleaning environmental assessment proved ineffective,
primarily because the data needed to make the comparsons are not yet available.
Sufficient emissions data and dilution factors are available to satisfactorily
approximate environmental concentrations. The critical lack, as noted elsewhere
in this report, is permissible concentration data.
In the absence of rigorous criteria for prioritization, decision
criteria to date have been subjective and based on general knowledge of the
identity of the pollutants of most concern and their emission rates. One
important external decision criterion has been the need to restrict preliminary
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considerations to a small, manageable number of pollutants, rather than the
whole population of potential pollutants.
Methodologies Being Developed
It was noted in preceding sections that there is a critical need for
a sound and rigorous method for converting toxicological and epidemiological
data to estimated permissible environmental concentrations, which does not
depend upon a number of arbitrary pr unsupportable assumptions.
Battelle's Columbus Laboratories is investigating this challenging
problem under Subtask 241, with the goal of developing an improved methodology
over those currently available. Achievement of the ultimate goal may be
beyond the reach of the current program, but it is anticipated that signifi-
cant progress will be made.
Two specific areas of achievement are (a) review of formulae for
estimating permissible concentrations, and (b) development of rationale for
extrapolation from animals to man and other organisms.
Numerous formulae for estimating permissible concentrations have been
identified and reviewed. The following references are typical of this effort:
Stokinger and Woodward ; International Commission on Radiological Protec-
tion ; Dawson et al., ; American Conference of Governmental Industrial
Hygienists ; Handy and Schindler and Kingsbury . Each formula is
reviewed according to the format: (a) situation or purpose of equation, (b)
the equation with explanation of all parts, and (c) rationale for biologically-
based portions of quantitative relationships. We have concluded that a formula
qualifies as "best" when it is (a) simple, (b) appropriate for mixtures, (c)
utilizes LDCQ> TLV or other quantitative toxicological measurements, (d) incor-
porates knowledge of target species, target organs and biological half-life,
(e) considers chemical state of pollutant mixtures, and (f) has a supporting
rationale for the use of safety or adjustment factors.
The second problem area arises in attempting to extrapolate toxicity
data from animals to man. The raw data encompasses a wide variety of test
animals and toxicant administration procedures, and methods are needed to
interconvert these data and to extrapolate them to man.
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Areviewof 15 articles, including Kleiber(12)13); Freireich, et al.( ;
Anderson and Weber ; and Goldsmith, et al. , shows there are two basic
methods for extrapolating toxicity responses from animals to man. In Method I,
responses of numerous species of various sizes to one toxicant are identified;
the reponse of various species untested by the same toxicant is projected with
the relationship
Y = aW
where
Y = a response
a = a constant (derived from regression of W, Y data)
W = organisms' weight
b = a constant (derived from regression of W, Y data).
In Method II, one equation deals with responses of many different
toxicants on one animal species; extrapolation proceeds from one animal species
to another.
Briefly, these methods are shown pictorially with non-linear scales
as follows:
Type I
0)
w
c
o
CX
CD
OJ
'elephant
Pig
dog
rat
mouse
Weight (w) of Various Animals
Type II
C.S.5
C.S.4
C.S.4
C.S.3
C.S.2
Chemical Species (C.S.)l
Response of Species 1
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Battelle plans to use these approaches along with the "best" formulae
to further develop estimated permissible concentrations of selected sub-
stances to humans, other organisms, and ecological systems around coal clean-
ing facilities.
Source Analysis Models
The source analysis model (SAM) basically involves the utilization of
normalized hazard factors determined by computing the ratio of concentration
of a pollutant in a stream to the goal concentration from the MEG analysis.
This approach is being investigated by another contractor, and no work on it
is being conducted at Battelle's Columbus Laboratories.
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REFERENCES FOR ENVIRONMENTAL
OBJECTIVES DEVELOPMENT SECTION
(pp. 63-69)
(1) Ewing, R. A., D. A. Tolle, S. Min, G. E. Raines, and V. L. Holoman,
"Development of Environmental Assessment Criteria", Draft Report to
U.S. Environmental Protection Agency, Battelle's Columbus Laboratories,
Columbus, Ohio (April 8, 1977), 46 pp + App.
(2) Handy, R. and Schindler, A., "Estimation of Permissible Concentrations of
Pollutants for Continuous Exposure", EPA-600/2-76-155, U.S. Environmental
Protection Agency, Office of Research and Development, Industrial Environ-
mental Research Laboratory, Research Triangle Park, N.C. (June, 1976),
136 pp.
(3) Min, S., Ballantyne, W. E. , Neuendorf, D. W., and Sharp, D. A., "Pollution
Control Technology for Coal Cleaning Processes", Preliminary Report to
U.S. Environmental Protection Agency, Battelle's Columbus Laboratories,
Columbus, Ohio (June, 1977) 220 pp.
(4) Cornaby, B.W., "Complex Effluent Assays, Heat, Noise, Microorganisms,
Radionuclides, Nonpollutant Factors", to be presented at EPA Contractors
Meeting on Environmental Assessment Methodology Development, October
13-14, 1977, Research Triangle Park, North Carolina.
(5) Duke, K. M. , Davis, M. E., and Dennis, A. M., "IERL-RTP Procedures Manual:
Level 1 Environmental Assessment Biological Tests for Pilot Studies",
EPA-600/7-77-043, U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina (April, 1977), 106 pp.
(6) Hamersma, J. W., Reynolds, S. L., Maddalone, R. F., "IERL-RTP Procedures
Manual: Level 1 Environmental Assessment", EPA-600/2-76-160A, U.S. Govern-
ment Printing Office, Washington, D.C., 1976.
(7) Stokinger, H. E. and Woodward, R. L., "Toxicologic Methods for Establishing
Drinking Water Standards", Journal American Water Works Association,
5£ (4): 515-529 (1958).
(8) International Commission on Radiological Protection. Recommendations of
the International Commission on Radiological Protection. Report of
Committee II on Permissible Dose for Internal Radiation. ICRP Publica-
tion 2. Pergamon Press, New York (1959) 233 pp.
(9) Dawson, G. W. , Stratley, M. W. , and Shuckrow, A. J., "Methodologies for
Determining Harmful Quantities and Rates of Penalty for Hazardous Sub-
stances", Vols I-III. Draft Final Report to U.S. EPA for the Division of
Technical Standards, Office of Water Planning and Standards. Battelle's
Pacific Northwest Laboratories, Richland, Washington (1974).
(10) American Conference of Governmental Industrial Hygienists. TLVs
Threshold Limit Values for Chemical Substances and Physical Agents
in the Workroom Environment with Intended Changes for 1976. Cincinnati,
Ohio. 94 pp.
70
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REFERENCES (Continued)
(11) Kingsbury, G. L., "Development of Multimedia Environmental Goals
(MEG's) for Pollutants from Fuel Conversion Processes", paper pre-
sented at Symposium on Environmental Aspects of Fuel Conversion
Technology, September 1977, Tampa, Florida.
(12) Kleiber, M., "Body Size and Metabolic Rate", Physiological Reviews
27_ (4): 54-541. (1947).
(13) Kleiber, M., "The Fire of Life: An Introduction to Animal Energetics",
John Wiley & Sons, New York,-pp 200-212 (1961).
(14) Freireich, E. M., Gehan, E. A., Rail, D. P., Schmidt, L. H., and
Skipper, H. E., "Quantitative Comparison of Toxicity of Anticancer
Agents in Mouse, Rat, Hamster, Dog, Monkey, and Man". Cancer
Chemotherapy Reports, 50_ (4): 219-244 (1966).
(15) Anderson, P. D. and Weber, L. J., "Toxic Response as a Quantitative
Function of Body Size", Toxicology and Applied Pharmacology, 33:471-475
(1975).
(16) Goldsmith, M. A., Slavik, M., and Carter, S. K., "Quantitative Prediction
of Drug Toxicity in Humans from Toxicology in Large and Small Animals",
Cancer Research, 35:1354-1364 (1975).
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ENVIRONMENTAL DATA ACQUISITION
Existing Process Data
Published environmental data from coal cleaning processes are
essentially nonexistent. The following discussion, resulting primarily from
Task 222, briefly characterizes the kinds of data that are anticipated and
the variations expected from simple physical to complex physical to chemical
cleaning.
Physical Coal Cleaning
The pollutants generated from coal preparation plants include those
contained in solid waste, contaminated water, particulates, and gaseous
emissions. The nature and quantity of pollutants resulting from coal prepar-
ation facilities vary significantly depending upon characteristics of coal
treated, coal cleaning technology utilized, pollution control technology
employed, and geological, hydrological, and meteorological conditions where
the preparation plant is located. For a given type of coal, two important
factors affecting the environmental consequences of coal preparation are the
coal sizes being treated and the unit operations employed. As the coal sizes
become smaller, in general, coal preparation requires more sophisticated
processes and becomes susceptible to producing more environmental pollution.
Coal preparation has been classified into four levels according to
the coal sizes being washed and then categorized into nine generic types of
plants based on coal cleaning processes employed as indicated in Table 4 of
"Current Process Technology Background".
Chemical coal cleaning processes constitute another type of plant
but the technologies are still in the development and testing stages. The
nine physical cleaning plant types represent the majority of coal preparation
facilities throughout the United States, and each type is expected to produce
different environmental consequences of coal preparation although there are
many similarities.
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Thus, a spectrum of potential pollutants will yield a wide variety
of kinds of environmental data. The most simple preparation plant consisting
of only crushing and sizing will have solid waste consisting of coarse rock
and tramp iron, air pollution of coal dust and dust from refuse piles, and
water pollution from surface run-off around the facility. As washing or
cleaning circuits are added, a quantity of contaminated process water is
then present. Even though raw water is impounded and treated, effluents
are acid or alkaline, and contain suspended solids, dissolved solids, iron,
ammonia, and sulfates. Sludge and coarse refuse are added to the solid
waste. Addition of dense media cyclones or other dense media treatments
will result in a small amount of an additive, usually magnetite, being present
in both the waste water and solid waste. Washing of fine coal results in a
fine refuse addition to the solid waste. Use of froth flotation introduces
more additives to both solid waste and waste water as chemical reagents are
used in the flotation process. They may be grouped into two major classes:
first, the residual organic and inorganic reagents added deliberately to
the flotation circuit, and second, the metal ions and complexes contributed
to the aqueous phase due to dissolution by some of the flotation reagents.
No quantitative data are available to show pollutant emissions associated
with froth flotation processing of coal, but, the amounts of flotation
reagents used in the process are very small and are kept at a minimum not
only because of economics but also to avoid the detrimental effects of excess
reagents.
The cleaned fine coal that has resulted from a wet process must be
dried. Thermal driers normally take coal that has been partially dewatered
by mechanical means and remove as much of the remaining water as may be
required by a specific market. Emissions from thermal driers include particu-
lates from the coal being dried and particulates in the form of fly ash from
the coal-fired furnace that supplies the drying gases. Gaseous emissions from
thermal dryers include carbon monoxide, carbon dioxide, hydrocarbons, sulfur
dioxide, and oxides of nitrogen—all furnace combustion products.
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Chemical Coal Cleaning
In the chemical cleaning of coal, the dissolution of sulfur and ash
minerals would be accomplished using acid, alkaline, and oxidation reaction
methods. Potential pollutants from chemical coal cleaning may include un-
reacted chemical agents, by-products of chemical reactions, and contaminated
process water as well as many of the wastes, particularly solids, that might
be expected from physical coal cleaning, a logical first step in any integrated
cleaning facility. Because chemical coal cleaning processes are still in the
development stage, however, very few data on the environmental impact of chem-
ical cleaning are available.
Air pollutants can originate from perhaps two or three types of
sources associated with a chemical cleaning process. The type of source
about which the least is known would be process vents. Although the pollutants
in the vent gases would be controlled by scrubbers or by thermal or catalytic
combustors, some residuals might be expected. For example, a positively iden-
tified air emission stream from the Meyers process emanates from a gas scrubber
vent as a stream containing 90 percent oxygen, 10 percent sulfur dioxide, plus
(unspecified) volatile organic compounds.
Another source of air pollutants would be that from combustion opera-
tions designed to provide for addition of reaction heat. The provision for
reaction heat may be necessary for the Meyers process, for example. Fortun-
ately, the air pollutants from combustion operations and their control are
well understood and should prove no problem.
The final source for air pollutants would be from thermal dryers.
For the most part, the air emissions would be similar to those produced by
thermal dryers used in physical coal cleaning operations, and similarly con-
trollable.
In chemical cleaning, potential air pollutants from the coal are
converted to water soluble salts. Thus, the process water contains high con-
centrations of dissolved salts. In addition, the process water may contain
other inorganic and organic materials. For the Meyers process, for example,
special care should be taken for the organic solvent (e.g., light naphtha)
74
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used in sulfur removal section. Naphtha has a measurable solubility in water
and can appear in the purge stream. The buildup of organic impurities in the
recycled organic solvent and trace elements in the process water stream may
be potentially hazardous. Other liquid wastes from the Meyers process may
include sulfuric acid, wetting agents, and agents to control foaming.
In addition to any phsycial cleaning wastes, as previously noted,
the solid wastes from chemical coal cleaning will include solid reaction
products and sludges produced by the neutralization of scrubber waters and
process waters. These waste (or by-product) reaction products and sludges
may contain organic materials used in the process or dissolved or vaporized
from the coal. Trace element concentrations, too, may be many times higher
than in the untreated coal or even its ash.
In the Meyers process, for example, large quantities of iron sul-
fates (mixed ferrous and feric) are produced as a by-product. Also produced
are gypsum, from the neutralization of the sulfuric acid which is not recycled,
and elemental sulfur. Although their quantitative levels have not been
established, many trace elements from the mineral constituents in the coal
will also be present in the solid wastes produced because the trace elements
will be dissolved and reprecipitated in the process. Organic wetting and
antifoaming agents and other organic materials (such as naphtha) used in the
process or perhaps dissolved from the coal may also be present in the solid
wastes.
It should be concluded that compositions of the many waste streams
by chemical coal cleaning processes need to be quantized.
Sampling and Analytical Techniques
Objectives
Task 431 of this contract was established to evaluate applicable
methods of sampling and analyses for the purpose of assessing the environmental
effects of coal cleaning plants. The steps to be followed in achieving this
objective include:
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• The application of sampling methods which are
appropriate to anticipated pollutants from
various media
• Recommend accepted or new methods of preservation,
storage, transfer and preparation of samples for
analyses
• Indicate the analytical methods which possess the
desired detection and sensitivity limits for the
expected pollutants at the required levels of
characterization
• Evaluate the assessment strategy of the phased
versus the direct approach in regard to convenience,
cost, and utility
• Complete writeup of the overall desired or recommended
procedures of sampling and analysis.
Development of Experimental Techniques
The phased approach for determining the extent of pollution potential
of a process is divided into three consecutive levels of effort. Level I is
used as a survey tool to identify existing broad problems and to evaluate the
possible adverse environmental effects of effluents. As such, representative
sampling is not required and analytical results within a factor of + 2 or 3
are acceptable. Level II is an extensive qualitative, semiquantitative program
that is intended to identify specific substances that exist in effluent streams
having significant environmental effects. Level III is a quantitative study
of the effects of process variables on the emission of specific substances
which Level II identified as causes of environmental effects.
An alternative to the phased strategy is the direct approach. This
approach requires quantitative analyses of one set of representative samples.
This is essentially a Level II procedure and assumes that prior knowledge is
available as to the nature of emissions of the technology being investigated.
To avoid repeated sampling trips to any one plant, Battelle recommends the
direct approach with the assumption that it will be less costly to over-sample
76
-------
on a single visit than to make a second visit. The result is that samples may
be taken at Level II intensity but screened at Level I and followed up with
Level II analysis as needed. This level of sampling will be justified because
we will have some prior knowledge of the effluents of a plant.
Existing methods for collection, preservation, transport, preparation,
and analysis of known or anticipated effluents from coal cleaning processes
have been surveyed and appropriate methods have been compiled. These are
summarized in Table 9.
Sampling, Sample Preservation, and Transport. The sampling for
chemical analyses for this assessment will deal only with the source materials
of and the carriers for pollutants as contrasted to in-process sampling. The
sources of pollutants are noted to be raw coal, refuse and ash areas, holding
ponds, and process chemicals. The carriers of the pollutants are air, water,
and sediments. Pollutant sinks such as vegetation, soils, aquatic biota, and
terrestrial mammals are believed to be best assayed for ecological contami-
nation in a Level III monitoring program where effects can be observed over
periods of time. Some of these samples will be taken and preserved for
possible future analysis.
Solid samples such as coal, ash, and refuse are taken by grab
sampling with a core tube or from a conveyor belt. These are stored in air-
tight plastic bags or plastic-lined metal containers.
Grab samples of water are taken by dipping or by use of a Van Dorn
or equivalent sampler. Preservatives can be added immediately.
Atmospheric pollutants include both gas vapors and particulates.
Gaseous emissions come from thermal drying of clean coal and combustion of
coal in thermal driers while particulate sources are crushers and screens,
refuse and coal piles, transfer points, ash from thermal driers, and vehicular
dust. Particulates are collected on glass fiber filter pads by hi-vol samplers
and by Andersen impactors which are placed downwind of the plant. Gaseous
emissions are collected either by adsorption by an XAD-2 resin for C?-C _
organic compounds or by admission into evacuated vessels for inorganic and
C^-Cg organic compounds. Preservation measures are designed to reduce pickup
of moisture by particulates, stabile biological activity and prevent photo-
chemical reactions.
77
-------
TABLE 9. SUGGESTED SCHEME FOR ANALYTICAL CHARACTERIZATION OF COAL CLEANING PROCESSES
CO
Media Sample Measurement
Atmospheric Particulate weight
available elements
Hg
S04
N03
cr
NH/
Bioassay
Organics
Particle size
Particle morphology
Gaseous ^-Cg
C7-C12
Metals
Bioassay
H2S
COS
Sampling Technique
Hi-Vol, 8"xlO" glass filter
Hi-Vol, 8"xlO" glass filter
Hi-Vol, 8"xlO" glass filter
Hi-Vol, 8"xlO" glass filter
Hi-Vol, 8"xlO" glass filter
Hi-Vol, 8"xlO" glass filter
Hi-Vol, 8"xlO" glass filter
Hi-Vol, 8"xlO" glass filter
Hi-Vol, 8"xlO" glass filter
Andersen Impactor
Andersen Impactor
Evacuated glass bulb
Adsorption-XAD-2
XAD-2 cartridge
XAD-2 Cartridge
Gas bag
Gas bag
Preservation(a) Sample Preparation
Store in sealed
plastic
Store in sealed Acid extract
plastic
Store in sealed Acid extract
plastic
Store in sealed Water extract
plastic
Store in sealed Water extract
plastic
Store in sealed Water extract
plastic
Store in sealed Water extract
plastic
Store in sealed Solid and water
plastic extract
Store in sealed Pentane solvent
plastic extraction
Glass Bottles None
Glass Bottles None
Glass None
Cap and Refrigerate Methylene chloride
extract
Cap and Refrigerate Parr Bomb
Cap and Refrigerate Pentane extract
(Store in dark to
reduce photochemical
reactions) None
(Store in dark to
reduce photochemical
reactions) None
Analytical Method , ..
Method^0) Reference1 '
Gravimetric
SSMS
AAS
1C
ISE
ISE
ISE
Cytotoxicity,
mutagenicity
GC, IR, LC (8
fractions); IR, GMS
Gravimetric
LM, SEM, TEN
GC-FID (on-site)
GC, IR, LC (8
fractions); IR, GMS
SSMS
Cytotoxicity,
mutagenicity
GC-FPD
GC-FPD
(3)
(4)
(4)
(4)
(5)
(1,6,7)
—
(8)
(6,7)
(1)
(5)
(1)
(1)
-------
TABLE 9. (Continued)
vo
Media Sample Measurement Sampling Technique Preservation (a)
Gaseous CS? Gas bag
(Continued)
CO Gas bag
C02 Gas bag
CN Gas bag
NH3 Gas bag
NOX Gas bag
sox
Aquatic Water Total elements Grab
Hg Grab
Acidity
Alkalinity
BOD
COD
Chloride
(Store in dark to
reduce photochemical
reactions)
(Store in dark to
reduce photochemical
reactions
(Store in dark to
reduce photochemical
reactions
(Store in dark to
reduce photochemical
reactions
(Store in dark to
reduce photochemical
reactions)
(Store in dark to
reduce photochemical
reactions)
(Store in dark to
reduce photochemical
reactions)
P or G, HNOa to pH <2(2)
P or G, HN03 to pH <2(2)
P or G, Cool, 4° C
P or G, Cool, 4°C
P or G, Cool , 4°C
P or G, H2S04 to PH2
P or G, Cool 4°C
Sample Preparation
None
None
None
None
None
None
None
Dry for residue &
briquette
Reduce & amalgamate
with Ag
on site
on site
on site
Analytical Method , ,
Methodlb' Reference1 '
GC-FPD
GC-TC
GC-TC
GC-TC
GC-TC
Chemi 1 umi nescence
GC-FPD
SSMS
AAS
Hach kit, or
equivalent
Hach kit, or
equivalent
5 day incubation
Dichromate oxidation
Hach kit, or
(1)
(1)
(1)
(1)
(1)
(1,9)
(1)
(10)
(10)
(4)
(4)
equivalent
(10)
-------
TABLE 9. (Continued)
Media Sample Measurement Sampling Technique Preservation(a)
Water 02
(Continued)
Hardness
MBAS
Total N
Total organic
co C
o
pH
Phenols Grab
Total P
Total resdiue
Conductance
Total S
Temperature
Organics
Bioassay
Solids Coal Total elements Grab
Hg
Total sulfur
G
F or G, Cool to 4°C
P or G, Cool to 4°C
P or G, H2S04 to pH<2,
Cool 4°C
Glass, H2S04 to pH <2,
Cool 4°C
P, G, Cool to 4°C
G, H3P04 to pH<4, 1 gr
CuS04/l, Cool to 4°C
P or G, H2S04 to pH<2,
Cool 4°C
F or G, Cool to 4°C
P or G, Cool to 4°C
P or G, 2 cc zinc ace-
tate; Cool to 4°C
P or G
H2SC°4 to pH<2 Cool 4°C
Plastic Bag
Plastic Bag
Plastic Bag
r -, n *- Analytical Method f }
Sample Preparation Methodtb) Reference^'
on site
on site
oxidize
on site
Distillation
Oxidation
Evaporation
on site
oxidize to sulfate
on site
methyl ene chloride ext
None
Parr Bomb
Parr Bomb
Direct
Portable oxygen probe
(or Winkler method)
Hach kit, or
equivalent
Colorimetric
Kjeldahl + N03
Beckman instrument
or equivalent
Portable pH meter or
pH paper
Colorimetric
Colorimetric
Gravimetric
Portable meter
1C
thermometer
LC (8 fractions)
Cytotoxicity,
mutagenicity
SSMS
AAS
Eschka, grav.
„
(10)
(4)
(4)
(4)
_.
(4)
(4)
(4)
—
(3)
—
(1)
(5)
(11)
-------
TABLE 9. (Continued)
oo
Media Sample Measurement
Refuse Total elements
Hg
Available elements
Available Organics
Bioassay
Acidity
Alkalinity
COD
Chloride
CN
Total N
Organic Carbon
PH
Phenols
Total P
Total residue
Total S
Total S
Sampling Technique Preservation (b) Sample Preparation
Grab Plastic Bag Direct
Grab Plastic Bag Direct
Grab -- Water leach
Grab — Methyl ene chloride ext
Water leach grind
solid
Water leach
Water leach
Water leach
Water leach
Water leach
Water leach
Water leach
Water leach
Water leach
Water leach
Water leach
Water leach
Analytical
Method(b)
SSMS
AAS
SSMS
GC, LC/IR-GMS
Cytotoxicity,
mutagenicity
(see methods for
water)
(see methods for
water)
(see methods for
water)
(see methods for
water)
(see methods for
water)
(see methods for
water)
(see methods for
water)
(see methods for
water)
(see methods for
water)
(see methods for
water)
(see methods for
water)
(see methods for
water)
Method / »
Reference1 '
(1)
(5)
(see water
references)
(see water
references)
(see water
references)
(see water
references)
(see water
references)
(see water
references)
(see water
references)
(see water
references)
(see water
references)
(see water
references)
(see water
references)
(see water
references)
(a) P- Plastic, G - Glass
(b) SSMS - Spark Source mass spectrometry; AAS-Atomic Absorption Spectrcmetry, IC-Ion Chromatography; ISE-Ion selective Electrode; LM-Light
Microscope; SEM-Scenning Electron Microscopy; TEK-Transmission Electron Microscopy; GC-Gas Chromatography; IR-Infrared Spectroscopy;
LC-Liquid Chroma tography; GMS-Gas Mass Spectrometry; FID-Flame lom'zation Detector; TC-Thermal Conductivity Detection; FPD-Flame Photometric Detection
(c) References are given at the conclusion of this section of the report.
-------
Sample Preparation. Each kind of instrumental analysis has its set
of operating ranges and conditions which requires that samples from whatever
source they come must be prepared for that analytical method. In general,
this requires samples, whether air, water, or solid, to be brought into solu-
tion by dissolution or extraction with appropriate solvents for chemical
analysis or bioassay or dried for gravimetric or spectrometric analysis. Com-
bustible solids such as coal will be burned and the residues taken up in
nitric acid.
Chemical Analyses^. Level I chemical analyses are performed by
methods with low detection limits. The methods listed in Table 8 are
sufficiently sensitive to identify potential pollution problems without
accurately measuring the pollutant concentrations. Inorganic elements in
solids and liquids will be analyzed by spark source mass spectrometry; in-
organic gases and low molecular weight organic compounds (C^-Cg) will be
analyzed by gas chromatography; and higher molecular weight organic com-
pounds (07-012) will be resolved for functional groups and typed by solvent
separation and analyzed by gas chromatography, infrared spectroscopy, and
gas mass spectrometry. Some analyses can be performed on site with reagent
test kits (Each or equivalent). Mercury is a special case of an inorganic
element for which atomic absorption spectrometry is the accepted method of
analysis even for Level I.
Bioassays. Level I bioassays are based on the exposure of organisms
to whole samples to estimate the potential adverse health and ecological
effects. Sensitive aquatic organisms are exposed to various levels of liquid
effluents to determine toxicity levels of the pollutants. Leachates from
solids can also be tested in this manner.
Gaseous samples are tested by the plant stress ethylene test in
which plants (soybeans) are exposed to the gaseous emissions for varying lengths
of time after which they are enclosed in plastic bags and the evolution of
ethylene by the plants monitored for several days.
82
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Test Development Program
The test program was developed under Subtask 411 to provide overall
guidance for the field program, identify sources of coal cleaning pollutants,
and select the ecological compartments to be evaluated for the environmental
effects of those pollutants. The test program is described in Battelle's
draft report^12^ of September 30, 1977.
The largest single source of potential pollution from coal cleaning
is solid waste. Potential impacts of solid waste include air, water, and
land pollution; safety hazards; and ecological and esthetic impacts. These
solids include soluble and suspendable materials which can produce acid
run-off, toxic solutions, and silted waterways. The greatest adverse
biological impact of solid wastes occurs as water pollution. Acid run-off
and leachate are products of reactions with the pyrite present in the refuse
pile, and it can leach into the groundwater as well as drain into surface
waters. Solid wastes can also contribute to air pollution in the forms of
blowing dust and smoke and gases from burning piles.
Polluted water can come from the preparation plant washing
processes as well as the solid waste run-off. Acid waters dissolve
metals and mineral salts which they contact. Lime treatment to decrease
the acidity can create highly alkaline waters with the precipitation of
calcium carbonate and metal salts which may affect aquatic organisms.
Silts and suspended solids cause changes in aquatic habitats.
Air pollution results from the dusts and particulate matter that
come from the mechanical and thermal processes in the preparation plants
as well as the gases, odors, and particulates from burning refuse and
coal piles. The biggest source of particulates is thermal drying. A
number of toxic trace elements and gases have been identified in emissions
from thermal driers.
Although it is quite localized, noise is another form of air
pollution which originates in the crushers, screens, conveyors, and other
parts of the coal cleaning plant.
The field test program is designed to assess the severity of these
environmental pollutants and the effectiveness of pollution controls. To
accomplish this, a well planned test program must be carried out to test,
83
-------
sample, and analyze wastes, effluents, and emissions from coal cleaning
plants which have been selected to be representative of the coal cleaning
processes and the environmental settings in which these plants are located.
The procedure for selecting these test sites and the general test plan
development are discussed briefly below.
Site Selection Procedure
To support the study of.coal cleaning and pollution control techno-
logies, Battelle will make field visits, measure environmental factors,
and take samples of process streams for subsequent laboratory analysis. A
site selection scheme has been developed to permit the study of as many
variables as possible with a limited number of field trips.
Four unique and important variables were selected for study. These
variables which are expected to have the greatest influence on the kinds
of pollution controls needed for coal cleaning operations are neutralization
potential (N), pyritic sulfur (S), annual precipitation (R), and process
technology (T).
Based on the low (0) and high (1) potential pollution levels for
each of these variables as shown in Table 10, 16 types of site categories
are possible. Six of these site categories are excluded from further consi-
deration because they are nonexistent, e.g., low rainfall which occurs in
the western U.S. in not consistent with high sulfur or acid conditions.
A basic statistical rationale for identifying sampling sequences for factorial
designs may be stated as follows:
• Early in the sampling sequence, sample those site
categories that permit the "main effect" of each
classification variable to be investigated; next
include those site categories that permit investi-
gations of the "interaction effect" associated with
two classification variables, then three classifi-
cation variables, etc.
This rationale is based on the assumption that the most desired information
is that associated with the main effects of single variables. After obtaining
84
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TABLE 10. CLASSIFICATION VARIABLES AND ASSOCIATED
LEVELS USED TO DEFINE SITE CATEGORIES
Variable Low Level (0) High Level (1)
N (Neutralization pH ^ 7.5* pH <_ 6.0*
potential)
S (Pyritic £ 1.0% >. 3.0%
sulfur)
R (Average annual _< 15 in/yr >^ 25 in/yr
rainfall)
T (Coal cleaning Plant Type A&B^ Plant Type F
process technology thru I?
* pH of soil in the receiving environment. As defined,
low level of N actually refers to a low pollution
potential which is, in fact, a high ability to neutralize
acid streams.
^ See Table 4 in "Current Process Technology Background"
for definitions of plant types.
85
-------
information on the effect of each classification variable, the next priority
is then associated with information on the combined effects of two classifi-
cation variables, etc.
Table 11 shows the recommended sequential sampling design for the
ten remaining coal cleaning plant categories. One site from each site
category is to be sampled in the sequence from 1 to 10, as shown in Column
2, with site category 1, defined as (1111), sampled first and site category
10, defined as (0000), sampled last. The sampling may be terminated after
sampling the first four site categories (Option C), after sampling the
first eight site categories (Option B), or after sampling all ten site
categories (Option A).
Once the existing coal cleaning plants have been classified into
these site categories, the next step of the selection process is that of
selecting specific sites within each site category. The specific sites
are intended to yield the maximum information concerning coal cleaning
impacts upon environments from a given number of sites. The selection
of specific sites is to be accomplished by applying constraints or defining
specific needs. Published information, telephone contact, and site visits
will be used to provide information on candidate sites. Constraints which
will be imposed in making the final site selections are shown in Table 12.
These constraints will be applied in the order shown.
Test Plan Development
The master test plan and the site-specific test plans are intended
to ensure that the testing is performed effectively with regard to costs,
schedules, and data requirements. This activity is designated as Subtask
451. The objectives dictate that the test planning subtask be a coordinated
activity involving several other subtasks. Determination of data requirements
comes about in part through interaction with the systems studies task (200
series) since one of the functions of that task is to identify data gaps in
the coal cleaning literature. Development of realistic testing cost esti-
mates and schedules requires participation of the key test personnel. Test
86
-------
TABLE 11. RECOMMENDED SEQUENTIAL SAMPLING DESIGN
FOR COAL CLEANING PLANTS
Group Site f.* Site Characteristics Geographic
Number Category^ (N, S, R, T)(2) Regions
1 1 (1111) NA
2 (1110) NA
3 (1011) NA
4 (0111) MW
2 5 (1010) NA
6 (0110) NA
7 (0011) MW, SA
8 (0010) MW, SA
3 9 (0001) W
10 (0000) W
(1) One site from each site category is to be sampled in the sequence
from 1 through 10, with site category 1, defined as (1111), sampled
first and site category 10, defined as (0000), sampled last. The
sampling may be terminated after sampling 4 site categories (Option
C), 8 site categories (Option B), or 10 site categories (Option A).
(2) See Table 10 for definitions of low (0) and high (1) levels for
neutralization potential, N, pyritic sulfur, S, average annual
rainfall, R, and coal cleaning process technology, T. The combin-
ation (1010), for example, denotes a site category with N and R
at level 1 and S and T at level 0.
(3) Geographic regions associated with the site categories are denoted
by Northern Appalachian (NA), Southern Appalachian (SA), Midwestern
(MW), and Western (W).
87
-------
TABLE 12. PRIORITIZED CONSTRAINTS USED IN SPECIFIC
SITE SELECTION PROCEDURES
Constraints
Essential
(1) Best practicable pollution control technology
(2) Plant management cooperation
Needed
(1) Two ages of refuse piles
(2) Plant capacity greater than the mean of the site category
(3) Baseline data available
Desired
(1) Minimal coal industries in area
(2) Nonmixed refuse piles
(3) Homogeneous coal source
planning personnel are involved in the site selection process described in
the preceding section to ensure that selected sites are physically reasonable
for sampling purposes.
To date, progress in test plan development has primarily involved
key test personnel input to the master test plan. Specialists in hydrology,
structural geology, water chemistry, air pollution measurement, air pollution
modelling, aquatic and terrestrial biota, and noise measurement have identi-
fied for their respective disciplines those test elements which will be
site-independent. These common elements are being integrated into a master
test plan. Approximately 15 percent of the work on the master test plan is
complete.
The site-specific test plans are, at the time of this writing,
awaiting selection of the first site. In development of specific site
test plans, coordination with the systems studies task will be especially
important in determining data requirements.
88
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Preoperational Environmental Monitoring
Homer City, Pennsylvania
A major environmental monitoring evaluation has been completed for
the U.S. Environmental Protection Agency in a study area containing an ad-
vanced physical coal cleaning facility, presently in the final stages of con-
struction at the Homer City (Pennsylvania) electric generating complex. The
Homer City generating complex is jointly owned by Pennsylvania Electric Com-
pany (Penelec), a subsidiary of General Public Utilities Corporation (GPU),
and New York State Electric and Gas Corporation (NYSEG). Because of the
technically advanced nature of the new coal cleaning facility, the U.S. EPA
has arranged for the collection and analysis of data, to enable an evalua-
tion to be performed of the effectiveness and cost of physical coal cleaning
techniques in controlling pollutants, principally sulfur and its compounds,
currently being emitted by power generation facilities. The primary objec-
tive of this environmental monitoring in the study area surrounding the
Homer City coal cleaning plant was to obtain background information on
environmental conditions prior to the operation of the coal cleaning plant.
Homer City Coal Cleaning and Generating Complex. The Homer City
station is part of an integrated power complex which includes coal mines;
coal cleaning, storage, and transport facilities; power-generation facili-
ties; and waste disposal facilities as illustrated by Figure 2. Coal used
at the Homer City station comes from two dedicated mines located at the site,
as well as coal hauled by truck from other mines. The Helvetia and Helen
mines are both deep mines which obtain coal from the Upper Freeport seam and
have life expectancies of approximately 50 and 30 years, respectively. Both
mines will deliver crushed coal to the new coal cleaning plant by conveyor.
The coal cleaning plant or MCCS will receive about 24 percent of its coal
from the Helen mine, 52 percent from the Helvetia mine, and about 24 per-
cent from coal trucked to the complex from nearby mines. Cleaned coal
will leave the cleaning plant in two streams, one with low and the other
with medium sulfur content for use in the Homer City station boilers. The
89
-------
Coal Sources
Helen Mine
Helvetia Mine
Trucked In
Coal Preparation
Crushers & Breakers at Mines
Multi-stream Coal Cleaning
Plant
Coal Storage
Active Pile
Reserve Pile
Power Units
#1) medium sulfur
#2 j coal
#3 low sulfur coal
Solid Waste
Refuse Disposal Area (from MCCS)
Ash Disposal Area (from power plant)
Boney Piles (from mines)
Liquid Waste Ponds
Refuse Leachate Ponds (2)
Ash Leachate Pond (1)
Coal Pile Runoff Ponds (3)
Bottom Ash Desilting Pond (4)
Emergency Holding Pond (1)
Water Treatment Facilities
Leachate Water
Industrial Waste
Cooling Tower Makeup
Boiler Feedwater
Sewage Treatment (2)
Streams Receiving Runoff and/or Effluent
Cherry Run
Blacklick Creek
Two Lick Creek
FIGURE 2. HOMER CITY POWER COMPLEX
90
-------
existing power units, numbers 1 and 2, will use the higher sulfur content
coal and the deep cleaned coal will be burned in the new power unit, number 3.
Solid refuse from coal mining, cleaning and burning will even-
tually be deposited in the three different types of disposal areas indicated
in Figure 3. Refuse from the cleaning plant and sludge from the emergency
holding pond will be stored in a newly created refuse disposal area. Both
the Helen and Helvetia mines will continue to dump their mine waste,
including high-ash coal or "bone" coal, in the boney piles near each mine
shaft. The ash disposal area is the third type of area for solid refuse.
It receives sludge dredged from the two coal pile run-off desilting ponds
which receive a slurry of bottom ash and pulverizer reject. Finally, fly
ash captured by the electrostatic precipitators is trucked from fly ash
storage silos to the ash disposal area.
Liquid wastes from coal mining, cleaning, and burning are
clarified and/or treated by several different methods prior to discharge
into tributaries of Blacklick and Two Lick Creek as indicated in Figure 4.
A proposed 4,000 gpm capacity plant will treat leachate water with calcium
oxide pellets and aeration before release into an unnamed tributary of
Blacklick Creek. Water entering this new plant will be pumped from
leachate settling ponds at the ash and cleaning plant refuse disposal
areas. In addition, mine drainage from the two mines at the complex will
also be treated at this new facility. In the event of an emergency,
slurry from the cleaning plant will be discharged into a seven-million-
gallon emergency holding pond, which also receives storm run-off and spillage
from around the MCCS. Two 135-foot-diameter static thickeners will clarify
water in the holding pond and return it to the cleaning plant.
Storm run-off from the coal storage area is diverted in ditches to
two desilting ponds where the suspended solids are permitted to settle.
Caustic is fed at the inlets to these ponds for neutralization and removal
91
-------
vo
NJ
Cleaned
Coal
Stockpile
Emergency
Holding
Pond
Bottom Ash
Desilting
Ponds
FIGURE 3. DISPOSAL AREAS FOR SOLID REFUSE FROM COAL MINING, CLEANING, AND BURNING
-------
MCCS
Emergency
Holding Pond
vo
u>
Station
Run-Off
Desilting
Pond
General
Plant
Wastes
Thickeners
Industrial
Waste
Treatment
Plant
Two Coal Pile
Run-Off Desilting
Ponds
Helen &
Helvetia
Mines
Proposed
Leachate
Water
Treatment
Plant
Four Bottom
Ash Desilting
Ponds
Leachate
Pond
FIGURE 4. LIQUID REFUSE FROM COAL MINING, CLEANING, AND BURNING
-------
of iron. Average flows from these ponds are pumped to the industrial
waste treatment plant and eventually discharged in a ravine leading to
Two Lick Creek.
Storm run-off from roof and paved surface drains at the power
station leads to a desilting pond after oil from the oil handling area has
been removed by a concrete oil separator-skimmer tank. Average flows from
this pond pass through an underdrain filter system before release into
a ravine. Sluice water, containing bottom ash and pulverizer reject, is
discharged into clay-lined settling ponds. Two of the four ponds used
for this purpose are in operation while sludge collected in the other pair
of bottom ash settling ponds is removed. Some clarified effluent from
these ponds is recycled for ash sluicing and the remaining effluent is
discharged into a tributary of Two Lick Creek.
General plant wastes not directly in contact with coal are also
treated at the industrial waste treatment plant. These wastes include
boiler blowdown water, furnace bottom-seal water, vacuum seal water, and
floor washing. This plant waste water, coal storage-pile drainage, and
some ash sluice water are neutralized by the addition of lime and then sub-
jected to air agitation. Prior to discharge into a ravine the water is
allowed to settle for removal of suspended solids. Sanitary wastes are
treated in two package sewage treatment plants sized for 5,000 and 12,000
gallons per day. After chlorination to 1-2 ppm residual, the effluent
flows into a ravine which discharges into Two Lick Creek.
Monitoring Protocol. Nine general environmental evaluation areas
at the Homer City complex listed in Figure 5 have been examined for a
variety of abiotic factors that involve sampling and analysis of fugitive
dusts, surface and groundwaters, and refuse. One or more of (1) minor and
trace elements, (2) sulfur, (3) waste water characteristics, (4) stream
flow, and (5) particulates were determined. A brief selected example of the
sampling performed in the environmental evaluation study area is shown
diagrammatically in Figure 6 for the cleaning plant refuse disposal area.
The 13 sampling sites are indicated by the numbers in circules. Samples of
the major input and output streams to this disposal area include solid
refuse from the cleaning plant, sludge from the emergency holding pond,
94
-------
1. Bottom and Fly Ash Disposal Area
2. Cleaning Plant Refuse Disposal Area
3. Treatment Plant for Leachate Water
4. Emergency Holding Pond for Cleaning Plant
5. Airborne Dust from Coal and R.efuse Transport
and Storage
6. Streams and Underground Aquifers With Potential to
Receive Pollution
7- Coal Pile Run-Off Desilting Ponds
8. Desilting Pond for Plant Facilities Storm Run-Off
9. Ash Sluice Water Desilting Ponds
FIGURE 5. ABIOTIC ENVIRONMENTAL EVALUATION AREAS
95
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Solid Refuse.
from MCCS
Airborne
Dust from
Piles
Storm
Runoff
\
Ground Water
up Gradient
x^ S
(n) /
fe\ Springs
Disposal
Area
Sludge from
Emergency
Holding Pond
©
i
T
Leachate
Flow by
Gravel |
Underdrains
Leachate
Pond
A
Leachate
Pond
B
Refuse Leachate
Water Pumped to
Treatment Plant
Direction of Surface &
Ground Water Flow
Water Sample
Upstream
1 Ground Water
Down Gradient
Leaching
into
8 J Surface
Water
Water Sample
Downstream
FTGURE 6. SAMPLING SITES AT CLEANING PLANT REFUSE DISPOSAL AREA
96
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and leachate water pumped to the treatment plant. In addition, the poten-
tial for leaching of pollutants into the surface and groundwater were
examined. Water samples and flow rates from the aquifer lying under the
disposal area were obtained both up and down gradient from the disposal
area by a series of piezometers. These samples were analyzed to determine
differences in concentrations of pollutants caused by leaching from the
disposal area. Similarly, storm run-off diverted around the disposal area
and surface water flowing downgradient from the leachate ponds were sampled
and their pollutant levels compared. Water samples from springs in the
disposal area and leachate flow in the gravel underdrains have been compared.
Finally, water and sediment samples and flow rates were obtained at sites
upstream and downstream from the reach of Cherry Run likely to receive
leachate from the refuse disposal area.
The other environmental evaluation areas noted in Figure 5 have
been sampled in a manner similar to the refuse disposal area, with appropriate
modifications for differences in direction of water flow, distance to other
potential sources of pollution, and differences in construction of the
facility.
Accepted sampling and analysis techniques have been documented for
most of the components of each of the five environmental parameters listed
earlier. Some additional techniques have been recommended by Battelle.
The Illinois Geological Survey recommended analysis techniques for 33 of
the minor and trace elements likely to be found in particulate samples.
Waste water characteristics including sulfur analysis methods have followed
those recommended by EPA in the Federal Register. Stream flow may be
determined by several different methods depending on the circumstances,
but the most widely used method was the current meter (pygmy meter).
Groundwater flows were determined from piezometer observations. Fugitive
dust particulate samples were weighed, analyzed for minor and trace
elements, and mass concentrations calculated.
97
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A computer simulation model was developed to predict the zones
of fugitive dust fallout and the predicted rates of dispersion of the fall-
out. This model will be further refined and utilized in Battelle's national
coal cleaning testing program.
General Results
The studies performed in December 1976, and April 1977, included
assessments of water quality, sediments (both surface and groundwaste) fugi-
tive dust, and aquatic and terrestrial biota. Three separate campaigns were
performed for water quality, sediments, fugitive dust and aquatic biota. A
single survey was performed of the terrestrial biota.
Aspects of water quality were measured at 41 sampling locations
on eight streams within the study area as shown in Figure 7. Overall
water quality ranges from fair to poor; the low level of quality is due to
aqueous discharges from existing facilities. Alghough water quality is
generally poor in the vicinity of facility operations and outfalls, within
a short distance downstream, because of inherent buffering and dilution
capacities of the stream quality improves. As would be expected in a coal
region lithology, the streams had quantitative levels of forms of iron,
manganese, sulfur, and calcium, high enough to be of concern. In addition,
oil sheens were present during all sampling periods conducted in the common
ravine area.
Conclusions
(1) The groundwater quality as measured and as recorded
in the literature is quite marginal to being unfit for
human and some animal consumption. The stream sedi-
ments of the area are heavily laden with metallic com-
pounds. But, the streams have a high level of oxygen
and, if it were not for the pH extremes and suspended
solids, the streams could begin a rather rapid recovery
as the chemical character of the stream returned to
background values for that region.
98
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Refuse disposal area
Coal pile
Coal cleaning plant
Power plant
Substation
Burial yard
Cooling towers
Stacks
Ash sluice ponds
Employees parking lot
Boney pile
Ash disposal area
Mine siltation ponds
Coal pile retention ponds
Rager's Pond
Paved road
o Surface water sample
• Groundwater sample
• Sediment and surface
water samples
FIGURE 7. WATER QUALITY SAMPLING LOCATIONS
99
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(2) In assessing the quality of aquatic life, it was found
that Cherry Run's tributary North of the coal cleaning
refuse area, now under construction, has good overall
biological quality. Similarly, the upstream portion
tributary south of the refuse was judged to be of good
aquatic quality.
Cherry Run was evaluated as having fair biological quality
based on the number of species of fish inhabiting this
stream. However, the quality of the biological community
inhabiting Cherry Run has been affected by both plant and
mining operations in the area. Low standing crops of
benthic macroinvertebrates and fishes clearly demonstrate
this purturbance.
The remaining streams, Wier's Run, Rager's Pond tributary,
Common Ravine and the downstream portion of the tributary
south of the disposal area were all considered to have
poor biological quality. Two Lick Creek was not rated
because of the small number of samples collected in this
study.
(3) A wide range of particulate loadings were found in the
vicinity of the coal cleaning plant (under construction).
The heaviest mass loadings occurred at stations located
200 meters downwind of the coal cleaning plant/coal pile.
At stations 2000 meters downwind the levels dropped to
those typical of an agrarian region. The stations that
were within 1000 meters of the site had a distinct
diurnal loading phase. In the daytime the mass weighs
were 50 percent higher than the contiguous nightime
values. The extent of obvious and significant impact
was found to exist to about 1200 meters downwind. The
snow cover assisted in determining the fugitive dust
impact area. The overall average of the coal particle
sizes at all stations was measured to be between 20 and
100
-------
70 microns in diameter. The average ash size at all
stations was in the 5 to 20 micron range. Coal was
the predominant material deposited on the hi-volume
and "Anderson" filters.
Trace element concentrations by chemical species was
not found to be directly related to the variance of
mass weights. The average trace element concentra-
tions were higher at 12-hour sampling sites than the
24-hour sampling sites. The 12-hour sites were
generally 500 meters downwind of the coal cleaning
plant site. Southwest winds prevailed at the site
for 70 percent of the time during the 3 sampling
campaigns. These southwest winds generated the
highest level of particulate loadings as compared
with the other major wind directions. The lowest
fugitive dust values were captured under a north-
west wind.
To support this fugitive monitoring activity a
multiple source fugitive dust dispersion model was
developed. It was field calibrated to the results
and source conditions at the Homer City Coal Cleaning
Plant. It is probably that this model will continue
to function well at other coal handling and storage
facilities. The utility of this model, besides being
able to predict dispersion levels with distance and
meteorologic conditions, is that it is a valuable
tool in choosing the optimum air sampling receptor
locations.
The fugitive dust chemical analysis revealed that
there is uncombusted coal dust at distances of 2000
meters downwind of the coal cleaning plant site; this
dust exhibits higher levels of lead, cadmium, arsenic
and mercury than is present in the whole coals analysis.
101
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Cadmium and lead values are several orders of magnitude
higher than the whole coal analysis. Beryllium and vanadium
were not found in the coal dusts; but these are quite evi-
dent in the source coals.
(4) The terrestrial habitats of the off site properties are
quite diverse and provide good to excellent habitats for
animal populations when compared to the current land use
common to that region. The area does not exhibit suit-
able conditions for water bird habitats. Due to the
accumulation of particulate matter in the neighboring
1 mile area it is expected that the plant biota there
soon will begin to show signs of stress.
The current design and construction of the refuse disposal facility
covers most of the important potential environmental problems in coal refuse
disposal, such as slope stability, erosion and leachate control. The actual
construction, however, as it existed in the field as of April 21, 1977, may
not completely control the migration of the heavy metal laden leachate.
This is principally due to the excavation of the main leachate collection
line into an unconsolidated sandstone saddle bench that surfaces on the site.
The second major problem with the site, as of the above date, was the con-
struction of a refuse area storm drain trunk line at a lower vertical dis-
placement than the leachate collection pond elevation in the first lift
area. This may permit the surface run-off leachates to by-pass the leachate
collection pond and treatment system.
MEG Pollutant List and Recommended
Additions for Consideration
No work has been performed under the coal cleaning program on deriva-
tion of MEG's for chemical pollutants. However, Battelle is working on es-
tablishing EPC's (and MEG's) for several nonchemical pollutants and non-
pollutant factors (such as noise) under Contract No. 68-02-2138(13) for assess.
ment of the environmental impact of fluidized-bed combustion processes. The
findings concerning EPC's will be applicable to the coal cleaning program
where the same pollutants or factors are involved.
102
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REFERENCES FOR ENVIRONMENTAL
DATA ACQUISITION SECTION
(pp. 72-102)
(1) Hamersma, J. W., Reynolds, S. L., and Maddalone, R. F. , "IERL-RTP
Procedures Manual: Level I Environmental Assessment", Report No.
EPA 600/2-76-160a, EPA Contract No. 68-02-1412, Task 18, Redondo
Beach, California, TRW Systems Group, June 1976.
(2) US EPA, ''Manual of Methods for Chemical Analysis of Water and
Wastes", EPA 625-16-74-003a, US EPA Technology Transfer, Cincinnati
(1974).
Dionex Ion Chromatography Operating Manual, 1976.
Standard Methods for Water and Waste Waters, 14 edition, American
Public Health Association, Inc., New York, New York (1975).
(5) Duke, K. M. , Davis, M. E., and Dennis, A. J., "IERL-RTP Procedure
Manual: Level I Environmental Assessment, Biological Test for
Pilot Studies", Report No. EPA 600-12076-160a, EPA Contract No.
68-02-2138, Columbus, Ohio, Battelle's Columbus Laboratories,
(May 1977).
(6) "Liquid Phase and Solid Support Applications to Chromatographic
Separation", Hewlett-Packard Applications Laboratory, Avondale,
Pennsylvania (1970), 67 pp.
(7) Snyder, L. R. , Analytical Chemistry, 33, 1527 (1961).
(8) McCrone, W. C., Draft, R., and Dilly, J. C., "The Particle Atlas",
first edition, Ann Arbor Science Publishers, Ann Arbor, Michigan
(1967), 406 pp.
(9) Black, F. M., and Sigsby, J. E., "Chemiluminescent Method for NO
and NOX (NO + N02) Analysis", Environ. Sci. Technol. 8 (2),
149 (1974).
(10) HACK Chemical Co., Water Test Kits (1974).
(11) Annual Book of ASTM Standards, Part 26, "Gaseous Fuels; Coal and
Coke; Atmospheric Analysis", D 3177-75, American Society for Testing
and Materials, Philadelphia, Pennsylvania (1975).
(12) Hale, V. Q., Clark, R., Stilwell, J. M., and Neuendorf, D. W.,
"Development of Experimental Text Program", draft report to US
EPA, Battelle's Columbus Laboratories (September 1977).
(13) Cornaby, B. W., "Complex Effluent Assays, Heat, Noise, Microorganisms,
Radionuclides, Nonpollutant Factors", to be presented at EPA Contractors
Meeting on Environmental Assessment Methodology Development, October
13-14, 1977, Research Triangle Park, North Carolina.
103
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CONTROL TECHNOLOGY ASSESSMENT
An assessment of pollution control technology for coal cleaning
processes was initiated as part of Subtask 222. A preliminary report on
this subtask, dated June, 1977, was prepared and submitted to EPA. The
results of this study, with respect to control technology for air pollution,
water pollution, and solid waste, are summarized in this section.
The information in this section applies mostly to the EPA outline
subheading entitled "Control Systems and Disposal Option Information and
Design Principles Application". A brief general commentary is supplied for
"Control Process Pollution and Impacts" illustrating major points. No work
has been done yet on this program with respect to the other subheadings in
the EPA outline under "Control Technology Assessment".
Preliminary information relating to costs is included in this
section rather than in "Environmental Alternatives Analysis" because the
Battelle program has not yet progressed to the stage of comparing alternatives.
Control Systems and Disposal Option Information
Air Pollution Control Technology
An evaluation was made of the various air pollution control techno-
logies to determine their applicability for treating emissions from coal cleaning
processes. Major factors considered in the evaluation of each control tech-
nology are performance, operational constraints and limitations, and costs.
Based on this evaluation, cost estimates are given for the most applicable
control technologies for controlling major emissions for two different sizes
of coal cleaning plants: 500 and 1000 tons per hour (tph).
Several types of air pollution control devices are available for
application to coal cleaning operations. The choice of the control device
depends on the type of pollutant (particulate or gaseous), the properties of
the pollutant (such as size, density, and shape for particulates, and equili-
brium solubility, reactivity, and adsorptivity for gases), and the properties
of the conveying medium (such as density, temperature, and velocity). Particu-
late control devices may be broadly classified as dry inertial collectors
104
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(gravity settlers and cyclones), filters, wet scrubbers, and electrostatic
precipitators. Control devices for the removal of gases or vapors involve
adsorption or absorption in a variety of contacting devices. Table 13 provides
a general outline of the mechanisms and types of equipment in common use today
for the removal of the two basic air pollutant types.
Considerations in the Evaluation of Control Equipment. Five major
sources of air pollution were identified for coal cleaning processes; they
are
• Crushing and sizing
• Pneumatic cleaning
• Thermal drying
• Coal storage, transportation, and handling operations
• Coal waste disposal areas.
In general, the fugitive emissions from coal storage, transportation and handling
operations, and solid waste disposal areas are not amenable to treatment by air
pollution control devices. The practical way of controlling these fugitive -——
emissions is prevention and, therefore, only the first three sources are consi-
dered in this section.
Several factors must be considered in the evaluation of equipment
for controlling the air emissions from coal cleaning processes. Important
factors are:
(1) Characteristics of air emissions and
operational constraints
(2) Control efficiency
(3) Capital and operating costs.
The air emissions from each of these three sources vary somewhat, but
certain generalizations can be made as to their characteristics. Typically,
the crushing and sizing operations produce dry, small particulates (0.5 to 6.0
microns) at ambient temperature. The quantity of dust generated depends on
the coal type, moisture level, and type of sizing and screening operations. In
the pneumatic cleaning operations, large volumes of dry particulates (~120
gr/dscf) are generated with particle sizes up to 100 mesh. The thermal drying
105
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(2)
TABLE 13. CLASSIFICATION OF EMISSION CONTROL EQUIPMENTV '
Control of
Control of Particulates Gases and Odors
Dry Inertial Collectors Dry Adsorbers
Gravity Settling Chembers Wet Absorbers
Cyclones
Fabric Filters
Electrostatic Precipitators
Wet Inertial Scrubbers
Impingement
Centrifugal
Venturi
Self-Induced
106
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operations produce high volumes of particulate emissions (50 to 200 gr/dscf) at
high moisture levels and temperatures above 200 F. Combustion gases containing
SO , NO , and CO, produced from the coal fuel, also accompany the particulates.
^ x
These emission characteristics dictate to a significant degree the type of
technology most applicable for their control. Factors such as temperature,
humidity, particle size distribution, loading, and the potential for an explo-
sion pose operational constraints on the control equipment.
The promulgated Federal standards of performance for new and modified
coal preparation plants, processing more than 200 tons per day, limit particu-
late emissions as follows:
• Not in excess of 0.070 g/dscm (0.031 gr/dscf) and
20 percent opacity for thermal driers
• Not in excess of 0.04 g/dscm (0.018 gr/dscf) for
pneumatic coal cleaning equipment
• Not in excess of 20 percent opacity (approximately
0.1 gr/dscf) for coal handling and storage equipment.
Some states have established standards more stringent than the above; in some
cases the presence of a visible dust plume is all but prohibited. To meet
these standards, the control equipment must either be highly efficient over a
wide range of particle sizes or operate in conjunction with another control
device and be selectively efficient for a specific range of particle sizes.
An important consideration in the evaluation of applicable control
equipment is the capital and operating cost. The installed costs vary signi-
ficantly with equipment types; and operating costs, depending on utility, raw
material, and maintenance requirements, can also vary substantially, making
some types of capital Intensive equipment with low operating costs appear
relatively attractive when capitalized over the life of the equipment.
Particulate Control Devices.
Dry Inertial Collectors. Dry inertial collection systems utilize
either gravitational or inertial forces to separate the particulates from the
gas stream. The collection systems are characterized by moderate removal effi-
ciencies, low energy requirements, low capital and operating costs, and an
107
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ability to accommodate high inlet dust loadings and operate at high temper-
atures. For applications at coal cleaning plants, the inertial collectors
are used primarily as scalping units or precleaners to remove the major volume
of particulates from pneumatic cleaner and thermal drier off-gases. To meet
the particulate emission standards, they are generally followed by more effi-
cient removal devices, such as high-energy scrubbers or filters.
Gravity settling chambers are among the simplest and oldest known
methods for particulate collection. The chamber consists of a large rec-
tangular, horizontal or vertical duct with a sufficiently large cross-sectional
area to reduce the velocity of the gas to below that of the terminal settling
velocity of the dust particles. The bottom of the chamber is equipped with a
hopper or collection chamber to collect the settled dust particles.
Gravity chambers are low in capital and maintenance cost, produce a
low pressure drop, and have no temperature or pressure limitations beyond those
of the materials of construction. They do, however, have large space require-
ments and low removal efficiencies for particles smaller than 75 microns diameter
(3)
at the typical design space velocity of 1 fps. Because of their poor perfor-
mance gravity chambers are not commonly utilized at coal cleaning plants for
treating any of the major emission sources.
Cyclones are the most widely used devices for particulate control.
Their simplicity of design, ease of operation, and low maintenance make them
one of the more trouble-free particulate collectors available.
Cyclones may be fabricated from a number of materials, and can be
used to collect particles over a broad range of pressures and temperatures
(from ambient to above 2000 F). They can also accommodate high inlet dust
concentrations, well in excess of 200 gr/dscf, and demonstrate increased removal
efficiency with increasing inlet particle concentration. Moreover, cyclones are
relatively compact, and can handle high volumetric flow rates, e.g., a 4-inch-
(3")
diameter cyclone can handle 100 to 150 scfm of air.
The major disadvantage of cyclones is their somewhat low collection
efficiency, particularly with particles smaller than 10 microns. Typical
efficiency ranges for conventional and high efficiency cyclones are shown in
Table 14. Because of its moderately high removal efficiency for large size
particles, coupled with its capacity to accommodate high dust loadings (above
3 grains/scf) and, in effect, fractionate a poly-dispersed dust stream, the
108
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C3")
TABLE 14. TYPICAL EFFICIENCY RANGES FOR CYCLONE COLLECTORS
Size Range
(microns)
5
5-20
15-20
40
Efficiency,
Conventional
Cyclone
NA*
50-80
80-95
95-99
percent
High Efficiency
Cyclone
50-80
80-95
95-99
95-99
* NA = Not Available
cyclone has become a common choice for reclaiming coal dust discharged from
pneumatic cleaners and thermal driers on coal preparation plants. When utilized
as primary reclaiming devices, cyclones are regarded as integral components of
the pneumatic cleaner or thermal drier and are not considered, from a cost stand-
point, to be emission control equipment.
Cyclones have no moving parts and are usually very reliable. The
major operational problems are erosion and corrosion, plugging of the dust out-
let or a build-up of cake on the walls.
Fabric Filters. Fabric or bag filters are regarded as one of the
simplest and most reliable high efficiency dry collector devices, being capable
of 99.9 percent removal of submicron size particles. They are suitable for a
wide variety of dry particulate removal applications, and depending on the
type of fabric selected, are resistant to chemical and mechanical rigors, and
are operable at moderately high temperatures.
The most common fabric filter device consists of several long, cylin-
drical bags, enclosed in a sealed vessel with a gas inlet and outlet, and a
dust collection hopper and discharge valve. Gas, contaminated with dust, is
passed through the fabric filter medium from either the inside or the outside
of the bag. The particulate matter impinges on and adheres to the filter
medium and is thus removed from the gas stream.
109
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Basically, two fundamental types of filter system are used, depending
on the type of filter medium and method of cleaning. The first type utilizes
a woven fabric filter bag, where the dust, which is usually collected on the
inside face of the fabric, builds up a thin cake which helps augment the
filtering action. As time passes and the dust cake continues to build, the
pressure drop increases to a point where it must be reduced to prevent a loss
of system capacity or bag rupture. The entire filter unit is temporarily shut
down and the filter bags mechanically shaken to dislodge the dust, or a compart-
mented section of the filter is isolated from the gas stream and cleaned mechan-
ically or with air. The woven fabric filter operates with a design volumetric
capacity of 2 to 3 cfm/sq ft filter area and A to 8 inches of water pressure
drop. Filter efficiencies range from 99.0 to 99.9+ percent for dust particles
down to the submicron size range.
The second filter type utilizes a felted fabric where the dust parti-
cles penetrate but do not pass through the fabric due to the constricted tortuous
path. These filters are cleaned continuously by intermittently subjecting
individual bags to a reverse jet or pulse while the remainder of the bags
continue filtering. The felted-fabric, continuously cleaned filters are designed
to accommodate 6 to 12 cfm/sq ft of filter area. They are capable of handling
higher dust loads and operate with more constant filter resistance than the
woven fabric filters.
Several different types of filtering media are available for fabric
filters depending on the application. The predominant factors in the selection
of the media type are thermal endurance, resistance to chemicals, and cost.
Fabric filters have several features that make them attractive as
particulate collectors, namely (1) very high removal efficiencies over a wide
range of particle sizes, (2) simplicity of operation, (3) relative compactness,
(4) no water requirements or creation of water disposal problems, and (5)
moderate operating pressure drops. These features make them a common choice
for collectors for dust control systems for crushing and sizing operations and
backup systems for cyclones on air tables.
The filters do, however, suffer from several operational restrictions.
The temperature at which they can operate is limited to 550-600 F for period-
ically cleaned filters and 250 F for continuously cleaned filters. This limi-
tation minimizes their applicability for flue gas or drier gas treatment.
110
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Moreover, the moisture in the gas must be low to avoid condensation and/or
bag plugging by the filter cake.
Electrostatic Precipitators. The electrostatic precipitator consists
of a chamber housing a series of high-voltage electrodes and a series of
grounded electrodes and collectors. The precipitation process involves charging
the airborne particles with ions in the electrical field produced between the
two series of electrodes and driving them onto the collector surface from where
they are removed by washing, vibrating, or rapping. The dislodged particles
fall from the surface into a hopper from which they are subsequently removed
for disposal.
The principal advantages of electrostatic precipitators are collection
efficiencies in excess of 99 percent for particles smaller than 20 microns in
diameter, low gas-phase pressure loss, and relatively low total power consump-
tion compared to other systems operating with comparable collection efficiency.
The major disadvantage, however, in dust removal applications for coal cleaning
plants, is the explosive nature of a coal dust-air mixture and the danger
imposed by the charged field in the precipitator. This danger precludes the
use of electrostatic precipitators for any of the coal dust control applications.
Wet Inertial Scrubbers. Wet scrubbers or collectors utilize a liquid,
generally water, to assist in removing the dust particles from the gas stream.
The major features that make wet collectors popular dust control devices are
their high removal efficiencies, ability to remove gaseous pollutants, tolerance
of moisture in the gas, and relatively low capital costs. Some disadvantages
inherent with wet collectors in general are (1) the captured particulate is in
the liquid state and sometimes presents a water or waste disposal problem,
(2) the scrubber internals are subject to plugging and corrosion, (3) the
scrubbed gas is saturated with the liquid vapor, and (4) the energy require-
ments for some units are high, resulting in higher operating costs than for
some dry collectors. Several different types of wet collectors are used for
particulate control; some of the more common are impingement, centrifugal,
venturi, and self-induced spray scrubbers.
Ill
-------
Impingement scrubbers consist of cylindrical or rectangular
chambers into which water is introduced through one or more spary nozzles.
The gas usually flows upward through the chamber where it contacts the
water spray and passes through a series of baffles or a packed bed and
finally through a centrifugal drum or chevron type mist eliminator to knock
out entrained water droplets before venting. Gas velocities are on the
order of 10 to 12 fps through the scrubber and water consumption is in the
range of 1/2 to 2 gallons per 1000 cu ft of gas. Pressure drops range from
1/2 to 8 inches of water.(^
The impingement separator is more suitable for removing particulate
material 5 microns and larger, as removal efficiencies are shown to be 97, 92,
and 85 percent, for 5-, 2-, and 1-micron particles, respectively. In addition
to the moderate removal efficiencies, the impingement separator is subject
to plugging.
Centrifugal scrubbers consist of a cylindrical vessel equipped
with spray nozzles and one or more stages of directional or centrifugal
vanes. The gas stream enters the bottom of the vessel where centrifugal
motion is imparted and where it is initially wetted to remove the larger
particles. After passing up through the directional vanes at a velocity of 6
to 8 fps and one or more washing stages, the gas is directed through the mist
eliminator and out the top of the scrubber. Water requirements are typically
2 to 10 gallons per 1000 cu ft of gas and pressure drops are usually 1-1/2 to
3 inches water gage. Removal efficiencies for smaller particles are relatively
low at only 90 percent for 5-micron particles.
In the venturi scrubber, scrubbing water is introduced normal to
the direction of gas flow, at, or upstream of, the constriction of the venturi,
where it is atomized and conducted with the gas stream into a centrifugal
separation chamber. The atomizing action helps induce contact of the water
with the particulates which are subsequently separated from the carrier gas
in the separation chamber. Approximately 3 to 10 gallons of water are required
per 1000 cu ft of gas.
The removal efficiency of the venturi varies with the power input
and can be increased to 99+ percent for submicron particles. As a result of
the high removal efficiencies attainable with venturi scrubbers, they have
112
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found common application in coal cleaning plants as dust collectors for the
grinding and sizing, pneumatic cleaning, and thermal drying operations.(5)
The self-induced scrubber consists of a vertical cylindrical
vessel consisting of baffle plates and various constrictions and one or more
standing water levels. The gas stream is directed around or through the con-
strictions to increase its velocity and then made to impinge upon the surface
of the scrubbing liquor. Removal efficiencies of self-induced scrubbers are
lower than those for venturi scrubbers and are less than 90 percent for
particulates 2 microns in size. Water requirements are lower than for most
other types of wet scrubbers at 1/4 to 1 gallon per 1000 cu ft of gas and
pressure drops are moderate at 3 to 6 inches of water.
Evaluation of Particulate Collection Devices. The information
compiled in the preceding discussion is assembled in tabular form to permit
an easier comparison and evaluation of the various types of particulate removal
equipment for their application in coal cleaning operations. Table 15 outlines
the operating constraints and removal efficiencies for each of the different
eq uipment typ es.
Based on the characteristics outlined for the three major emissions
from coal cleaning unit operations, and the performance evaluation of the con-
trol equipment, those equipment types most appropriate as control equipment
for each major emission may be selected. The selections are presented in Table
16.
Gaseous Removal and/or Collection Devices. Gaseous removal and/or
collection devices are designed to extract specific gaseous compounds from a
carrier gas stream. Although not practiced to date, the major potential
application for gaseous removal devices in coal cleaning operations is for
the removal of S02 from thermal drier off-gases. To this end, two major
types of gaseous removal processes, dry adsorption and wet absorption, can
be considered for controlling sulfur dioxide emissions. Both processes have
achieved commercial status in flue gas desulfurization for utility and in-
dustrial boilers. They are not, however, efficient dust removal devices,
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TABLE 15. DUST COLLECTOR CHARACTERISTICS AND
APPLICATION CHART(8'
Dust
Collector
Louver
Settling
Chamber
Low-
efficiency
Cyclone
High-
efficiency
Cyclone
Wet
Scrubbers
(Spray tower
and other
scrubber
types)
Fabric
Filters
(unit frame,
bag and
reverse- jet
types)
Venturi
Scrubber
Electro-
static
Precipi-
tator
Operating
Particle Dust Temperature, Operating Space
Size Load F Efficiency Requirement
30 microns Medium
and up to heavy
20 microns Light to
and up (200 heavy
mesh is
ideal)
1 micron Very light
and up to very
heavy
All Light to
heavy
Minus 200 Light to
mesh medium
All Light to
heavy
Very Light to
fine medium
Up to
1,500
Up to
1,500
Up to
1,500
Up to
1,500
Cotton:
175
Wool:
225
Dacron:
275
Fiber-
glass:
550
Up to
1,500
Up to
550
. 45% for 30
microns to 99%
on flyash
75% on all
plus 325 mesh
95% on plus
10 micron
feed
80% in 1 to
10 micron
range
Up to 100%
in 10 micron
range
99%+ in 1 to
10 micron
range
90 to 100
Medium
Needs
consid-
erable
space.
Small
and
compact.
Small
and
compact .
Small
to
medium.
Small
and
compact.
Small
to
medium.
Remarks
No moving parts.
Will handle heavy
surge. Coarse sizes
can cause excessive
wear. Good as a
scalping unit.
Usually placed
out of doors
because of bulk.
No moving parts.
Best on plus 20
micron sizes.
Good for classifying,
Can handle heavy
dust loads.
Excessive moisture
will blind fabric.
Good on fumes .
Requires high water
supply, up to
1,000 cfm.
Most efficient
system for handling
extremely fine dust
and fumes . Not
suitable for use
on explosive
mixtures.
114
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TABLE 16. SUMMARY OF APPLICATIONS FOR PARTICIPATE
CONTROL EQUIPMENT
Emission Source
Typical
Characteristics of Dust
Appropriate
Control
Crushing and Sizing
Operations
Pneumatic Cleaners
Thermal Dryer
Dry, submicron up to about
6 microns In size; light
dust load, ambient temperature
Dry, submicron up to 48 mesh
in size, heavy dust load
(>100 gr/dscf), ambient
temperature
High humidity, submicron up
to about 100 microns in size,
heavy loadings up to 200 gr/
dscf, temperature 200 to 250 F.
Cloth filters or
high-energy
wet scrubbers
(a)
Primary cyclone- '
cloth filter or
primary cyclone-
high-energy
wet scrubber
Primary cyclone-
high efficiency
wet scrubber
(a)
(a) Not considered as emission control equipment but rather as pneu-
matic cleaner or thermal drier process equipment utilized to recover
coal.
115
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and to meet partlculate control regulations must be used in conjunction
with or preceded by a high-efficiency wet scrubber.
Dry Adsorbers. Removal of sulfur dioxide from flue gas or drier
off-gas may be accomplished by either molecular sieves or carbon adsorption.
Unfortunately, molecular sieves have a greater affinity for water than for
SO , and since water in flue gas or drier off-gas is present in considerably
greater concentrations than SO-, the sieve is rendered essentially ineffective
unless preceded by a drying device., i.e., another sieve.
The most practical adsorbent for SO- from coal-processing-related
gas streams is activated carbon which has been demonstrated to be an effective
adsorbent of SO- at temperatures of less than 300 F. Two primary drawbacks,
however, to a carbon-based system are the limited capacity and low gas velocity
requirements. The sorbent capacity is generally only about 2 to 10 percent
sulfur by weight and the rate of adsorption of S09 on carbon is limited to the
rate of SO- diffusion into the pores. Thus, large quantities of adsorbent
must be used and gas velocities must be limited to 1 to 4 feet per second.
Adsorption is a high-initial-cost process which can vary from $7 to
$13 per cfm for installed carbon steel units without regeneration to $14 to
(9)
$25 per cfm with regeneration. Operating costs consist of the blower power
requirements and regeneration or adsorbent make-up costs and can run $0.60 to
$1.20 per 1000 cfm-yr.
Wet Absorbers. Absorption is regarded as the most developed method
for removing S02 from flue gases, and to date, several hundred various commer-
cial-size installations have been applied worldwide to utility and industrial
boilers.
Several different types of absorption equipment are utilized to
effect contact of the gas with the scrubbing slurry; some of the more common
types are spray towers, venturi scrubbers, and marble bed scrubbers. A
variety of different aqueous solutions are also utilized to capture the SO .
They may be classified into four different categories: slurry solutions,
clear solutions, weak acid solutions, and organic liquids. The most developed
systems to date are those utilizing slurry solutions in spray towers or
venturi scrubbers.
116
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Slurry solutions involve the use of a 5 to 15 percent lime or lime-
stone slurry to absorb S0~. The spent absorbent, CaCO and CaSO^, is transferred
to a disposal facility and discarded as waste. Removal efficiencies range from
70 to 90 percent of the SO. in the inlet gas.
The attractive feature of the lime/limestone-based scrubbing system
is that the low cost of the absorbent eliminates the need for regeneration ^-
facilities. But, alternately, provisions must be made to dispose of the CaSO^
and CaSO, waste, reheat the flue gas, if necessary, and grind the limestone.
Estimated Plant Costs. Based on the emission characteristics and
equipment costs compiled in the preceding sections, an estimate can be made
of the costs for air pollution control technology for each of the three
emission sources.
These costs are presented as installed capital costs and operating
costs for hypothetical 500 and 1000 tph coal cleaning plants with the follow-
ing levels of treatment:
Crushing and Sizing Plant (Level 1)
Medium Size Coal Beneficiation Plant with Air Tables (Level 3)
Fine Size Coal Beneficiation Plant with Thermal Drying (Level 4)
A more detailed description of each plant and its characteristic
emissions is provided in "Current Process Technology Background". This pre-
liminary cost analysis was limited to the above three cleaning levels be-
cause they each contain at least one of the three major emission sources
described earlier.
As summarized in Table 17, for some plants more than one particulate
control device is applicable; in this case, cost estimates are prepared for
each type of treatment. For the Type F plant, an additional cost was include
to account for flue gas desulfurization on the thermal drier. This prelimi-
nary analysis is given as an example. Other alternatives will be appraized
for sulfur control for thermal driers, e.g., firing with cleaned coal in some
cases. Limestone scrubbing was selected as the basis for the cost estimate
due to its more developed status.
The summary of the estimated installed and operating costs for each
pollution control system are presented in Table 17.
117
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TABLE 17. ESTIMATED COSTS OF AIR POLLUTION CONTROL
EQUIPMENT FOR COAL CLEANING PLANTS
Plant Type
and Emission
Applicable
Control Equipment
Installed Cost of
Control Equipment,
Dollars (1977)/tph
Annual Operating
Cost of Control
Equipment, (•)
cents/ ton
500 tons/hr 1000 tons/hr 500 tons/hr 1000 tons/hr
Type C.F.G.H, or I
(Level 1): Dust enclosures
Dust from crushing with dry bag
and sizing operation collectors
Dust enclosures with
high-efficiency
wet scrubbers
52
30
36
20
0.2
0.2
Primary cyclones
followed by
.high-efficiency
wet scrubbers
220
200
10.0
0.1
0.2
Type C (Level 3) :
Air tables
operating on
medium- size
coal
Primary cyclones 400 360
followed by dry
bag collectors
2.8 2.8
9.7
Type F.G.H, or I
(Level 4):
Thermal dryers
associated with
fine size coal
beneflciation
Primary cyclones 270
with high effic-
iency wet scrub-
bers
Primary cyclones 9450
with high-effic-
iency wet scrub-
bers followed by
limestone scrub-
bing
250
9250
12.5
93.8
12.2
93.8
(a)
Excludes capitalization, depreciation, and interest. Based on 180 (2-shift) days.
118
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Additional Information Required. To more accurately determine pollu-
tion control costs for the different plants, the equipment capital and operating
cost information should be better quantified. In addition to more accurate
modular costs, information is also needed on instrumentation and control,
installation, power, and maintenance costs.
Furthermore, to more effectively assess the possible environmental
problems associated with disposing of the collected particulate wastes generated
from the crushing and sizing operations, information is being sought on the
characteristics of the wastes. Knowledge of the composition, leachability and
chemical activity of the wastes would be helpful in determining any potential
environmental complications with their disposal as well as alternative handling
or disposal procedures.
Water Pollution Control Technology
Process and scrubbing water effluents from coal cleaning operations
contain two types of pollutants: suspended materials (solid or liquid) and
dissolved substances. The technology available for removing suspended mater-
ials from the water includes mechanical dewatering, sedimentation, and flotation.
Dissolved substances can be removed from water or converted to less objectionable
forms by neutralization, adsorption, ion exchange, reverse osmosis,, freezing,
or biological treatment. Table 18 lists the methodology currently in use or
contemplated for use in treating coal cleaning waste water.
Before assessing the applicability of these classes of technology
to various coal cleaning waste streams, a brief description of each class is
presented. Information relevant to this assessment includes removal efficiency,
and operational constraints. Potential water treatment technologies
are then matched with significant emission sources. Each source/technology
pair is evaluated with respect to anticipated performance, and capital and
operating costs for typical coal cleaning plant configurations.
119
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TABLE 18. CLASSIFICATION OF WATER TREATMENT
TECHNOLOGIES
Control of Control of
Suspended Materials Dissolved Materials
Mechanical Dewatering Neutralization
Centrifuges
Filters
Sedimentation
Settling Ponds
Sedimentation Tanks (Thickeners)
Flocculation
Control of Suspended Materials. Suspended solids may be removed
from liquid streams by mechanical dewatering methods, sedimentation, or flo-
tation. Each of these methods produces a solid material which may be processed
further in the coal cleaning plant, in the case of a coal-rich material, or
disposed of as solid waste.
Mechanical Dwatering. Mechanical dewatering devices applicable
for removing solid materials from water include centrifuges and various kinds
of filters.
A centrifuge is a device which rapidly rotates a solids-containing
stream in order that centrifugal force can separate the solid and liquid
fractions.
The perforated basket centrifuges use centrifugal force to filter
water through perforated sides, while removing trapped solids from the base
of the cone. The solid bowl centrifuge has a helical conveyor inside a trun-
cated conical solid bowl, both of which rotate at slightly different speeds.
The solids are removed at the apex end of the bowl by the helical conveyor,
while the water exits at the base of the cone (the lip of the bowl). Perfor-
ated basket machines require at least a 40 percent solids feed, while solid bowl
centrifuges can handle more dilute slurries.
120
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None of the centrifuges completely remove fine suspended materials
from water. As a water treatment device, a centrifuge is useful for roughing
purposes and would be followed by sedimentation, filtration, or some other
finishing method. Thfe centrifuge has found application, however, as a
dewatering device for the land-destined thickener underflow.
Vacuum filters are used in the dewatering of fine coal products
and fine refuse from wastewater. Although a drum type of vacuum filter is
available, only the disc type will be addressed in this report as it has
been the traditional choice in coal cleaning plants.
The disc type vacuum filter consists of a number of discs arranged
along a single axis with the assembly sitting in a rectangular chamber. As
the discs rotate, a vacuum pump pulls water and suspended solids through the
submerged portion of the screen fabric discs. As the cake rises from the water,
the air pressure within the disc is maintained at slightly above atmospheric
pressure to loosen the cake from the fabric. A scraper and conveyor system
finally remove the cake from the screen surface before the fresh filtering
surface is submerged again.
Standard models of disc-type vacuum filters range in disc diameter
from 4 to 12 feet and in surface area from 20 to 2400 square feet.
Granular media filter's may either be gravity or pressure filters.
Pressure filters are generally used in smaller plants where package units
are economical or where the additional pressure in the effluent can replace
a pump(s) downstream.(12) jn either case, the bed of granular filter medium
has a depth of 18 to 30 inches. The influent water filters up or down through
the bed under the force of pressure or gravity respectively. When the filter
capacity drops to a given level as a result of loading of the medium, the
load is shifted to another filter(s) while the bed is backwashed in prepara-
tion for another cycle.
Filter media available for use include silica sand (most common),
crushed anthracite, diatomaceous earth, perlite, and activated carbon. Two or
more of these media may be combined (layered) for a multimedia bed, or a
gradation of particle sizes of one material may be used; all of the possible
combinations of media and particle sizes produce different filtering charac-
teristics with a given waste water.
121
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Sedimentation. Sedimentation processes allow suspended materials
to settle to the bottom of a vessel and incorporate means for continually
removing settled solids and supernatant liquor separately. Systems classified
under sedimentation include settling ponds or lagoons and various configura-
tions of sedimentation tanks.
A settling pond or lagoon is the simplest and largest capacity
approach to sedimentation. It consists simply of routing wastewater with or
without flocculants to an excavated area. Suspended solids settle out in the
lagoon, and the supernatant is continuously decanted either to a stream, with
or without additional treatment, or back to the plant. When the depth of the
sediment in the lagoon reaches a predetermined level, the solids are dredged
or otherwise removed to a disposal area. Depending on the permeability of
the ground and the nature of the wastewater, a lagoon may or may not have to
be lined with clay, concrete, limestone» or other material.
Advantages of lagoons include low maintenance, no daily sludge
disposal problem, and flexibility with respect to flow rates, (l-^)
Thickeners are available in a variety of configurations, including
rectangular, square, round, and inverted pyramidal.^- ' Flow through the
pyramidal unit is upward, with sludge pumped continuously from the apex
(bottom) and clarified effluent overflowing at the top. Round thickeners
use radial horizontal flow and rectangular units use parallel horizontal
flow; the horizontal flow types all have sloping bottoms, with continuous
sediment removal at the lowest point.
Thickener size varies between 35 and 200 feet in diameter for round
units, with depth of 7 to 15 feet. Rectangular units as long as 300 feet with
length-to-width ratios of 3:1 to 5:1 exist. Bottom slopes range from 1 degree
to 8 degrees. '1^'
Filtration and sedimentation can be improved by the addition of
flocculants. Among commonly used additives are alum, lime, iron salts,
sulfuric acid, starches, and polymers. Although polymers are the most ex-
pensive, on a per unit basis, they are used in very small concentrations and
work very well.
122
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Control of Dissolved Materials. The most common pollution problem
of dissolved substances in wastewater is pH control. For coal cleaning waste-
water, and drainage from coal and refuse piles, the problem is usually
acidity, so an alkaline additive is needed; lime is the preferred reagent for
this purpose.
In an acid waste stream from a plant, lime is added to neutralize
the wastewater. The CaSC-4 or other insoluble precipitate which is formed is
removed in a thickener or other solids-removing device and disposed of as a
solid waste.
Applicability of Wastewater Treatment Processes to Coal Cleaning
Process Waste Streams. In this section each potentially applicable treat-
ment process is matched with each type of water stream from the nine generic
types of coal cleaning plants and evaluated with respect to anticipated
performance. Capital and operating costs (including depreciation and
interest on capital) for typical water pollution control facilities are
documented in Table 19 for three types of plants. In addition to the nine
plant types, the storage, transportation, and handling of coal, which are
common to all types of plants, are evaluated.
In generating the treatment costs, it was assumed that all water
treatment is performed to satisfy environmental constraints. Actually, much
of the treatment, particularly dewatering, is an integral operation in the
coal cleaning process. Thus, all or a portion of the costs cited may be attri-
buted to process requirements rather than environmental requirements.
Since the use of a closed water circuit is a viable alternative to
treatment and release of wastewater, much of the water treatment will be
aimed at upgrading the wastewater to render it suitable for process use.
In the absence of information on the actual treatment flows, the
process water flow characteristics of each plant type have been used to estimate
the capital and operating costs for process water treatment. These cost
estimates probably represent some extreme maximum resulting from an overestimate
of the size of the treatment facility required, from an overestimate of the
flow rates, and from lack of knowledge about number of operating hours per
year (for the treatment facility).
123
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TABLE 19. ESTIMATED COSTS OF WATER POLLUTION CONTROL EQUIPMENT FOR
SELECTED 1000 TPH COAL CLEANING PLANTS
S3
-C-
Plant Type
Crushing and
Sizing with
Dry Screening
and Wet
Beneficiation
Crushing and
Sizing with
Wet Screening-
and Wet
Beneficiation
Fine Size Coal
Beneficiation
with Hydroclones
and Thermal
Drying
Quantity,
Effluent gpm
Process Water 3,450
Flow-
Suspended Solids
Dissolved Solids
Process Water 7,650
Flow-
Suspended Solids
Process Water 9,250
Flow-
Suspended Solids
'
Applicable Control
Equipment
Radial flow thickener
lagoon, or
froth flotation
Absorption-activated
carbon treatment
Mechanical dewatering-
hydroclones ,
microscreens, or
pressure filters
Thickener or
lagoon
Radial flow thickener
or lagoon
Installed Cost of
Control Equipment,
(1977 Dollars)
345,000
108,000
33,000, . .
1.700,000W
150,000
230,000
310,000
510,000
160,000
560,000
180,000
Annual Operating
Cost of (b)
Control Equipment
cents/ton '
•
0.8
0.6
0.7-1.4
2.0
1.4
1.0
1.8
1.2
0.8
1.3
0.9
(a) Adsorption is not presently used to treat coal cleaning process water, and would not be necessary for treating the
recirculating process water for any plant with a closed water circuit.
(b)
Including depreciation and interest on capital.
-------
Information on wastewater treatment costs will be refined for the
final report on pollution control technology for coal cleaning processes.
The final report will also discuss the allocation of waste treatment costs
relating to process and environmental requirements.
Type A Preparation Plant. The coal cleaning plants described as
Type A perform crushing and sizing operations only. Since the operations are
performed dry, there are no process water streams in the plant.
Type B Preparation Plant. A Type B coal cleaning plant is a Type A
plant followed by dry screening at 3/8-inch and wet beneficiation of plus
3/8-inch material only, with jig or heavy medium vessel. Mechanical dewatering
is performed on the plus 3/8-inch product. The minus 3/8-inch material is
mixed with the course product. The untreated process water contains TSS, TDS,
alkalinity, iron, manganese and some metals.
Since the process water stream in a Type B plant is the result of
mechanical dewatering, further mechanical dewatering probably would not be
sufficient to remove the remaining suspended solids from the stream. A
lagoon or thickener would most likely be the method of choice for removal of
suspended solids from the process water. In either case, alum, or some other
flocculant, would be added to decrease settling time, since coal particles
are rarely readily settleable without flocculants. Both thickeners and
lagoons produce a solid waste stream (the thickener continuously, the lagoon
intermittently) which must be either disposed of or in some cases reprocessed
for use as a fine, clean coal.
The pH of coal cleaning plant process water is routinely main-
tained between 7.3 and 8.1 for those processes recycling the process water.
Water reciruclation or pollution control needs therefore should not require
any further neutralization.
Type C Preparation Plant. A Type C coal cleaning plant is a Type B
plant with an air table circuit added to clean minus 3/8-inch coal. No
difference in process water quantity or quality is expected between Types B
and C. Thus, identical treatment technology should be applicable.
125
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Type D Preparation Plant. A Type D plant is a Type A plant followed
by wet screening at 3/8-inch, and Type B beneficiation of plus 3/8-inch material,
It includes wet concentrating table beneficiation of minus 3/8-inch material,
mechanical dewatering of plus 28-mesh product, and discard of minus 28-mesh.
The process water is expected to contain higher concentrations of suspended
solids than plant Types B and C, and the quantity of water flow is expected
to be considerably greater due to concentrating table requirements. The
process water flow is 7650 gpm for a 1000 tph plant.
Thickeners, lagoons, and froth flotation would be applicable treat-
ments for Type D plant water, as they are for Type B.
With a closed water circuit, only the process pH control should be
necessary.
Type E Preparation Plant. A Type E coal cleaning plant is the same
as a Type D plant, with the concentrating tables replaced by heavy medium
cyclones. The quantity of process water in the Type E plant (10,200 gpm for a
1000 tph plant) is greater than for a Type D plant (7,650 gpm for a 1000 tph
plant). In addition to the constituents in Type D plant wastewater, magnetite
particles will be present as suspended solids in Type E plant wastewater, but
the applicable treatment processes should be similar to those used for a Type D
plant.
Type F Preparation Plant. A Type F coal cleaning plant is the same
as a Type D plant except that the Type F plant includes wet beneficiation of
minus 28-mesh material with hydrocyclones and thermal drying of minus 28-mesh
product. The process water flow is approximately 9,250 gpm for a 1000 tph
plant, which is greater than that for a Type D plant, but suspended solids
content should be lower for a Type F and comparable to a Type B plant. Thus
the same water treatment methods used for a Type B plant should be applicable
to Type F.
126
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Type G Preparation Plant. A Type G coal cleaning plant is the same
as a Type D plant except that the Type G plant includes froth flotation for
minus 28-mesh, and thermal drying of minus 28-mesh product. The process water
flow is approximately 7750 gpm for a 1000 tph plant, which is intermediate
between plant Types D and F. Suspended solids content should be about the same
as for a Type F plant. Flotation reagents in the water may constitute an
additional problem in a closed water circuit or wastewater stream.
Applicable treatment methods should be essentially the same as for
a Type F plant, for all pollutants,except flotation reagents. These reagents,
however, are not expected to build up in the water circuit, since they are
probably removed with the coal or waste solids. The reagents which leave the
plant in this way are potential water pollution problems in coal and refuse
runoff or potential air pollutants in thermal driers. Some residual flotation
reagents may also leave the plant in any treated wastewater streams.
Type H Preparation Plant. A Type H coal cleaning plant is the same
as a Type E plant, except that the Type H plant includes wet beneficiation of
minus 28-mesh coal with hydrocyclones, and thermal drying of minus 28-mesh
product. The process water flow is approximately 11,450 gpm for a 1000 tph
plant, which is greater than for a Type E plant, but suspended solids content
should be lower for the Type H plant and comparable to a Type B plant. Thus,
treatment methods useful in a Type B plant should be applicable to a Type H
plant.
Type I Preparation Plant. A Type I coal cleaning plant is the same
as a Type E plant, except that the Type I plant includes froth flotation for
minus 28-mesh, and thermal drying of minus 28-mesh product. The process water
flow is approximately 9,950 gpm for a 1000 tph plant which is intermediate
between plant Types E and H. Suspended solids content should be about the
same as for a Type H plant. Flotation reagents in the water may constitute an
additional hazard, as in the case of a Type G plant. The water treatment
methods useful for Type G plants should also be applicable to Type I plants.
127
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Coal Transportation, Storage, and Handling. The major type of
water pollution arising from the transportation, storage, and handling of
coal is leachate from coal storage piles which is in general very much like
acid mine drainage.
All forms of treatment for the leachate are preceded by a collection
pond of some kind. The collection pond would also serve the function of a
settling pond or lagoon, removing most of the suspended solids. Certain other
treatment, such as lime neutralization, may take place in the pond itself.
Subsequent treatment would take place downstream before the water is released
to a stream or used in the plant.
No further treatment for suspended solids should be necessary after
the collection pond. The acidity and much of the metals content of the
water would be removed by lime neutralization in the collection pond.
Coal Waste Disposal Areas. The drainage from coal refuse storage
areas is very much like acid mine drainage and drainage from coal storage piles
The leachate from coal refuse areas is usually mixed with any drainage from
the mine before treatment. The same treatment methods used for coal storage
pile leachate would apply to refuse area drainage and mine drainage. Since
the refuse contains much more inorganic matter than coal, the refuse area
drainage should have somewhat higher concentrations of acid, iron, and other
acid-soluble minerals. Thus, the treatment system for refuse pile leachate
should be of higher capacity than that for coal storage pile leachate.
Items Requiring More Information. Much of the information presented
in this report is based on preliminary information and estimates. Many of
these approximations will be replaced by more exact information in the final
report. Contacts are being made with plant operators and vendors to obtain
more detailed capital and operating costs of control equipment, especially as
applied to the specific plant types. More information is being acquired on
disposal of waste streams produced by ion exchange and reverse osmosis treat-
ments. This data acquisition task will eventually be able to provide
detailed information on performance of control equipment, and actual pollutant
128
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concentrations in raw and treated water streams. In addition, the propor-
tions of treated and untreated process water will be determined, making it
possible to estimate actual pollution control costs more accurately.
Solid Waste Control Technology
Properties of Physical Coal Preparation Refuse. Coal preparation
refuse can be expected to contain all of the inorganic substances found in
the raw coal. An important constituent of coal preparation refuse is sulfur.
Physical coal preparation removes primarily the inorganic sulfur forms, pyrite
and marcasite. These may be present in quantities from less than 0.1 percent
to as much as 7.1 percent by weight.(1°) The presence of these sulfur com-
pounds has important implications for acid generation from the refuse.
Other trace elements found in coal refuse are not uniformly distri-
buted. Some elements, particularly Ge, Be, and B, have been found to concen-
trate in the organic fraction of coal and, therefore, are not likely to be
as abundant in the refuse. A second group of trace metals, including Hg, Zr,
Zn, Cd, As, Pb, Mn, Mo, Si, Al, Ca, and Fe, tends to concentrate in the
mineral matter and therefore in the refuse.
Particle sizes and size distributions, specific gravity, and
in-place density of the coal preparation refuse seem to be similar to ordinary
non-cohesive (sandy) soils.
Potential Problems from Land Disposal of Coal Preparation Refuse.
Generally, the problems caused by land disposal of coal waste fall into these
categories: aesthetics, blowing dust and debris, gas generation, fire poten-
tial, erosion, leachate, and final land use.
The potential aesthetic impact is largely site-dependent. Good
disposal practice would have the working area of the disposal facility held
to a minimum and other areas kept vegetated until needed and revegetated upon
completion.
The refuse generated by a coal preparation plant contains consider-
able quantities of fine particles, leading to potentially serious fugitive
129
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dust problems. Site selection is partly the solution to this problem. The
orientation of the valley with respect to prevailing winds should be considered
A crusting agent may be employed to prevent water infiltration and fugitive
dust from refuse piles.
Gas generation within the refuse has not been identified in research
so far as a potential problem. However, as there still remains a considerable
amount of organic matter in the refuse, fire resulting from spontaneous
combustion in the refuse banks is a matter of concern. Compacting the
coal preparation refuse piles will, minimize air circulation and reduce the
likelihood of fire. In addition, sealing the pile, either with an occasional
soil covering or with a crusting agent, also may reduce the fire potential.
Particle sizes are such that the refuse is particularly susceptible
to erosion. Diversion ditches to minimize flow of water over the refuse
surface, as well as siltation basins to capture eroded material, are essential.
The supernatant liquid (leachate) from the siltation basin should be monitored
for high pH, sulfate, calcium, total dissolved solids, and heavy metals before
being discharged to the environment. Treatment of this liquid may be necessary.
Because of the heavy metals concentration in coals, the leachate from
the refuse can be expected to be high in metal ions. This is especially true
if the leachate is acidic, as most of the metallic minerals are quite soluble
in acid.
It is possible to minimize leachate production from a disposal
facility by (1) diverting away all surface drainage, (2) applying a cover
material to prevent infiltration of rainfall, (3) grading to promote rapid
run-off (but not so rapid as to create excessive erosion), (4) minimizing the
open (working) area, and (5) applying a vegetative cover upon completion of
an area. In most cases, a naturally impermeable soil, or in some cases a
synthetic liner, is used to prevent infiltration of the leachate into the
ground and eventually the groundwater. An underdrain system is needed to
gather the leachate and carry it to a leachate treatment system. Leachate
treatment will probably consist of lime neutralization and settling. As well
as improving pH, lime treatment also will remove large quantities of metal
ions, which are relatively much less soluble at higher pH levels. However,
additional physical or chemical treatment may be required.
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Present and Future Limitations Imposed by State and Federal Laws.
The Resource Conservation and Recovery Act of 1976 (RCRA) was signed into
law on October 21, 1976. The law authorizes financial and technical assist-
ance to state, regional, and local agencies to develop comprehensive programs
for environmentally disposing of solid waste, including both hazardous and
non-hazardous waste. Coal preparation refuse clearly falls under the laws
definition of solid wastes.
Primary enforcement responsibility will be delegated to the states.
Minimum criteria for acceptable state programs must be developed by U.S. EPA
by October, 1977- These criteria will include appropriate methods and degrees
of control of solid waste disposal facilities to protect public health and
welfare, protect quality of groundwater and surface water from leachate,
(18)
protect surface waters from run-off, and provide for safety and aesthetics.
The U.S. EPA is to establish criteria for determining specifically
which materials fall into the category of hazardous wastes. The hazardous
waste criteria presently being considered are flammability, corrosiveness,
"reactivity", radioactivity, toxicity, and potential for bioaccumulation,
(19)
persistence, and potential for causing disease. Any material found to
meet the criteria established for any of these hazard classifications will
be considered a hazardous waste.
For wastes which may contain soluble hazardous constituents, the
leachate from those wastes will be tested against the hazardous waste criteria.
The leachate will be generated using a standardized technique now being
developed. If the leachate is found to be hazardous, the solid material it
was derived from will be considered hazardous. For coal refuse, the criterion
most applicable will be toxicity, principally due to the heavy metal ion con-
centrations expected to be in the leachate. Other criteria such as pH and
sulfate ion concentration may be important as well.
If the refuse, by virtue of its leachate, is not considered hazar-
dous, standard sanitary landfill practice, as outlined by Federal guidelines
and enforced by the states, will apply.
In 1974, U.S. EPA issued guidelines to be applied to Federal disposal
facilities and which were recommended for use by the states. These guidelines
are still highly relevant and, with some updating regarding leachate collection
(21)
and treatment, may be used as a basis for the guidelines required by RCRA.
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Site selection will be of primary importance. A refuse disposal
site should have adequate isolation, through physical barriers or by distance,
so as not to create a nuisance by virtue of noise, dust, or traffic, to nearby
residences. The site should be oriented to the prevailing wind in such a way
as to minimize blowing dust. A thorough hydrogeologic investigation will be
required to determine the depth of soil, groundwater, and geologic strata
underlying the site. Water pollution can be prevented by locating the site
away from lakes, streams, wells, and other water sources; avoiding sites where
subsurface strata will allow leachate to reach water sources, e.g., fractured
limestone and sandstone; providing good surface water diversion and site
drainage to minimize infiltration of water into the fill area; tightly com-
pacting the residue; collecting and treating leachate if necessary; and never
depositing residue directly into groundwater or surface water. As coal pre-
paration refuse does not present most of the problems associated with garbage,
daily cover may not be required.
If coal preparation refuse is found, by leachate testing as described
previously, to be hazardous, there probably will be only a few additional
requirements. The principal changes will be in the management/permit system
and in the degree of leachate control needed. Periodic reports to the respon-
sible state will be required. Furthermore, a permit will be required from
either U.S. EPA or the state for each hazardous waste disposal facility.
These requirements fall into the category of "added paperwork" and do not
affect the design or operation of a facility. In addition to the leachate
collection and treatment described earlier, a liner may be required to assure
that no leachate is allowed to escape the site.
Monitoring wells are certain to be required for a hazardous waste
site. These will have to be installed upgradient and downgradient to detect
changes in groundwater quality. Contingency plans will have to be made a
part of the permit process in case leakage should occur and in case any other
accident or spill should occur.
Coarse Refuse Disposal. Coarse refuse is considered to be refuse
larger than 28 mesh. It is generated by all levels of coal preparation (Types
A-I). There have been four major methods of coarse refuse disposal. The
method selected depends upon topography, economics, regulations, and other
factors.
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The four common disposal methods are:
(1) Valley-fill dumps
(2) Side-hill dumps
(3) Cross-valley fill
(4) Waste piles.
With the methods above, refuse is generally transported and placed
by aerial trams, conveyors, or trucks. These transporting/dumping techniques
lead to very loose, unstable fills, which in turn lead to refuse bank fires,
acid generation, erosion, and slope failures. Present day engineering demands
careful compaction, usually by means of bulldozers at the dump site. Further-
more, the Buffalo Creek disaster in 1972 has led to legislation and engineering
improvements which have reduced the numbers of impounding cross-valley fills.
Fine Refuse Disposal. Fine refuse is considered to be refuse smaller
than 28 mesh. It is generated by Level 3 and 4 preparation plants (Types D-I).
Fine refuse occurs as the thickener underflow and may contain 75 percent
moisture. Therefore, handling of fine refuse is generally done hydraulically,
by pumping the slurry from the preparation plant to a disposal area. Direct
disposal of the fine slurry into streams is no longer practiced. Disposal of
fine refuse will be by slurry impoundment, dewatering, or underground disposal.
Earth or coarse refuse is often used to build dams or dikes to
impound fine refuse slurries. The particular type of impoundment is related
to topography and many times to the method used for coarse refuse disposal.
Types of impoundments parallel the coarse refuse methods. These impound-
ments usually serve multiple functions—to provide for collection and storage
of water and to remove, by settling, the suspended solids from the fine refuse
slurry. Impoundment disposal is a convenient and relatively inexpensive way
of disposing of fine coal refuse.
The National Dam Safety Act, Public Law 92-367, was passed shortly
after one of these slurry impoundments, the Buffalo Creek dam at Saunders,
West Virginia, failed, causing heavy loss of lives and property. The act was
intended to greatly improve the engineering of refuse embankments which are
intended to, or which might, impound water. The result of this Act has been
economic pressure on the coal industry to eliminate slurry ponding. Therefore,
the next two methods have received increased attention.
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Fine refuse slurries may be dewatered, allowing the resulting fine
solids to be disposed of together with the coarse refuse fraction. There
are four categories of dewatering methods available for potential application.
• Mechanical dewatering is done by filtration and by
centrifuge, with the addition of flocculants. (The
addition of flocculants to the refuse may affect its
mechanical properties in a land disposal facility, its
leaching characteristics, and its utility for other
purposes.)
• Thermal dewatering is accomplished with driers or
incinerators.
• In situ dewatering usually involves placing layers of
fine refuse slurry alternately with layers of coarse
refuse, allowing the moisture to drain. Another tech-
nique, electrokinetic densification, has not yet been
applied to surface disposal of fine refuse but has been
' successfully used for years to dewater fine-grained
soils in a variety of construction projects.
• Chemical solidification of the fine refuse involves
addition of chemicals to produce a solid material
with substantial strength, while allowing the moisture
to be freed.
Returning coal refuse to underground mines has long been practiced
in Europe. A study done in 1975 for the National Science Foundation showed
that disposal of coal refuse in underground mines is technically, but not
economically, feasible in most cases.
Dewatering and handling of fine refuse may be made more difficult in
the future. This is due to the smaller particle sizes created by a number of
new techniques being investigated to improve pyritic sulfur removal from coal.
These techniques include magnetic separation, electrophoretic separation,
electrostatic separation, and 2-stage froth flotation.
134
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Secondary Pollution and Other Problems from Waste Dipsosal. Air
pollution may result from blowing dust and from refuse bank fires. Both of
these sources are controllable.
Leachate and surface drainage will result from coal refuse disposal
in most parts of the country. Both can be collected and treated. U.S. EPA
has published effluent standards for new and existing coal refuse areas. Table
20 shows those standards for new sources.
TABLE 20. EFFLUENT STANDARDS FOR NEW COAL
REFUSE AREAS
Effluent Characteristics
Total suspended solids,
mg/1
Iron, total, mg/1
Manganese, total, mg/1
PH
Daily
Maximum
70
3.5
4.0
6-9
30-Day
Average
35
3.0
2.0
6-9
Reclamation of Waste Disposal Area. It is estimated that the coal
waste piles and impoundments accumulated between 1930 and 1971 in the United
(23)
States cover approximately 225,000 acres of land. The most positive
approach to preventing pollution from disposal areas is probably reclamation.
Refuse piles are very similar to spoil banks and thus reclamation of refuse
piles can be achieved through similar procedures to those practiced for the
reclamation of mine spoil banks.
The reclamation procedures can be divided into these steps:
Contouring. Contouring involves shaping the surface of waste dis-
posal areas to achieve some predetermined objectives. The top surface of an
area is sloped to conform with the surrounding countryside. Terraces are often
used to control water run-off. Bulldozers are generally used to spread and
compact the refuse, and some compaction is done by the refuse hauling vehicles.
135
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In most cases, it is necessary to add a soil capable of supporting
plant growth. Twelve or eighteen inches of fine soil or topsoil cover is
capable of supporting vegetation.
Conditioning. Conditioning of the soil is essential on some coal
wastes prior to attempts at revegetation. Salinity, pH, and nutrient content
are among the most important factors which must be improved. Agents which
have been demonstrated to increase pH are lime, crushed limestone, and fly
ash. Nutrients may be added by standard fertilizers or along with sewage
sludge used for pH control.
Revegetation. In areas studied by the Bureau of Mines, grasses
combined with legumes gave the best results. Mulches are used after planting
or during planting to protect the seed and soil from drying.
Costs of Disposal and Reclamation. The Bureau of Mines studied the
costs of refuse disposal and reclamation for nine coal waste disposal projects.
The results disclosed that refuse disposal costs ranged from 13 to 29 cents
per ton-mile, spreading and compacting ranged from 4 to 28 cents per ton, and
(24)
soil covering and planting ranged from $1,070 to $2,319 per acre. These
costs did not include the cost of installing or operating leachate collection
or surface drainage collection and treatment facilities.
A report done by the Institute of Mining and Minerals Research at
the University of Kentucky stated that coal refuse disposal costs ranged from
(25)
$0.50 to $1.00 per ton, although specific disposal methods were not described.
Waste Utilization. Because the potential pollution problems associated
with refuse disposal are so great and because coal refuse offers significant
combustion heat content and other mineral values, serious consideration is being
given to its utilization as a raw material. The coal industry and the government
are developing new uses and reexamining earlier uses for coal refuse.
136
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Landfill. Refuse can be used as landfill for a variety of construc-
tion purposes. One coal mine in West Virginia has converted a refuse pile into
useful real estate. The Bureau of Mines has reported that refuse sites have
(24)
been used for housing and small industrial development.
Road Construction. Coal refuse has been used extensively in Britain
as a road base and for embankments. Adequate compaction is considered to be
the main factor in successful utilization, and composition is of secondary
significance. Refuse has successfully competed with conventional aggregates
on an economic basis.
Building Materials. Coal refuse can be used as a raw feed in cement-
making to replace the clay fraction. The refuse provides the silica and alumina
required for the preparation of Portland cement clinker. Coal refuse also is
being used in the manufacture of brick. Coal refuse is also used in the manu-
Cjc.\
facture of lightweight aggregates for the building industry.
(27)
Sulfur Compounds, A U.S. patent reveals that coal refuse containing
pyrite could be used to produce elemental sulfur and pelletized coherent calcium
carbonate.
Heat. Since coal refuse still contains a significant combustion heat
content, it can be used as a fuel. It has great potential for application in
the thermal drying of fines.
Metals. Work done by the Institute of Mining and Minerals Research of
the University of Kentucky showed that aluminum and the transition metals
"(28)
exist in coal refuse piles in sufficient quantities to be of economic interest. .
Additional Data Needs. Further data are needed on the relative
proportions and total amounts of fine waste that are being dewatered and dis-
posed of with the coarse refuse, as opposed to being disposed of in slurry
ponds. An idea of the trends in the proportion would also be helpful.
137
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Costs should be updated to include the costs of constructing and
operating leachate and surface drainage collection and treatment systems and
the costs associated with combined coarse and fine disposal.
More data are needed on leachate characteristics of both the fine and
coarse waste, particularly as to heavy metal concentrations, as these are
expected to be the determining factor in deciding whether coal refuse is or is
not hazardous. More data are also needed on the physical characteristics of
the refuse, especially of dewatered fine refuse.
Control Process Pollution and Impacts
No contractual activity was performed by Battelle-Columbus in this
specific area. The following two sections provide a general commentary
relating to pollution and impacts resulting from air and water pollution control.
No significant pollution results from any of the solid waste control measures.
Air Pollution Control
Air pollution control equipment on coal cleaning plants captures
particulates and gases that are destined for the atmosphere and transforms
them to solids or sludges. The disposition of the solids and their potential
for environmental impact is determined by the type of control equipment, the
type of coal cleaning equipment the control equipment is installed on, and the
process configuration of the coal cleaning plant.
Particulate control equipment functions principally as gathering
devices, transforming the airborne particulates into dry solids or sludges
and add no additional, or secondary, pollutants to the solid stream. The
collected solid, depending on the coal cleaning process configuration, is
either combined with the product coal stream as with control equipment on
pneumatic cleaners or some thermal driers, or combined and disposed of with
the coal refuse. As the quantity of captured particulate represents only a
small fraction of the coal refuse, no additional environmental impact is expected
beyond that attributed to the coal refuse itself.
138
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Some gaseous control equipment, specifically that for SCL control,
can generate sludges. The most common S0_ control systems, those using lime
or limestone, generate a calcium sulfite or calcium sulfate sludge. The sludge
waste is unfortunately of little commercial value and must be disposed of.
The most environmentally sound methods for sludge disposal are landfilling of
chemically fixed sludge and disposal of untreated sludge in ponds lined with an
impervious material such as clay, plastic, or rubber. However, calcium sulfite
presents a significant land use problem. Sulfites tend to crystallize into
small, thin platelets which settle to a loose bulky structure that may occlude
a relatively large amount of water. The sludge is difficult to compress and
dewater, and conversion to a suitable landfill presents an expensive and
formidable problem. Ponds on the other hand require a large, suitable disposal
site close to the plant and may not only be structurally unstable but aesthe-
tically objectionable.
Water Pollution Control
Wastewater treatment equipment designed for removing suspended
solids from coal cleaning plant process water are essentially gathering devices
serving to remove suspended particles from the water stream and collect them
in a solid or sludge form. No additives other than flocculants are generally
introduced into the wastewater, and the collected solids are either combined
with the coal product and sold or are disposed of with the coal refuse. The
composition of the produced solid waste is generically the same as that of the
coal refuse and it would not be expected to add to the environmental impact
beyond that to be attributed to the coal refuse itself.
Wastewater treatment equipment designed for the control of dissolved
solids, typically pH control, results in the addition of a small amount of
calcium sulfate to the solid wastes. Calcium sulfate is relatively innocuous,
insoluble, and would not be expected to add to an might even result in a slight
reduction of, the environmental impact of the coal refuse.
139
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REFERENCES FOR CONTROL
TECHNOLOGY ASSESSMENT SECTION
(pp. 104-139)
(1) Min, S., W. E. Ballantyne, D. W. Neuendorf, and D. A. Sharp, "Pollution
Control Technology for Coal Cleaning Processes", preliminary report to
U.S. Environmental Protection Agency, Battelle's Columbus Laboratories,
Columbus, Ohio (June, 1977), 220 pp.
(2) Lund, Herbert F., Industrial Pollution Control Handbook, McGraw-Hill,
New York, N.Y. (1971).
(3) Air Pollution Manual, Part II, American Industrial Hygiene Association,
Detroit, Michigan (1968).
(4) Industrial Gas Cleaning Institute, Inc., "Air Pollution Control Technology
and Costs in Nine Selected Areas", prepared for U.S. Environmental
Protection Agency, September, 1972.
(5) Sedman, C. B., "Coal Preparation Study", Draft report prepared for the
U.S. Environmental Protection Agency, December, 1973.
(6) Zimmerman, 0. T., "Dust Collectors", Cost Engineering, January, 1972,
pp. 4-5.
(7) Anon., "Marshall and Swift Equipment Cost Index", Chemical Engineering,
March, 1977.
(8) "Dust Control Methods", Coal Age, August, 1967, p. 56.
(9) MSA Research Corporation, "Package Sorption System Study", prepared for
U.S. Environmental Protection Agency, Contract No. EHSO 71-2, April, 1973.
(10) Choi, P. S. K., et al., "S02 Reduction in Non-Utility Combustion Sources",
prepared by Battelle Memorial Institute for the U.S. Environmental
Protection Agency, EPA-600/2-76-073, October, 1975.
(11) Guthrie, K. M., "Capital Cost Estimating", Chemical Engineering, March,
1969.
(12) "Process Design Manual for Suspended Solids Removal", U.S. Environmental
Protection Agency, Washington, D.C. (1975).
(!3) Coal Preparation, Edited by J. W. Leonard, et al., Third Edition, AIME,
New York, N.Y. (1968).
(14) Weber, W. J., Jr., Physicochemical Processes for Water Quality Control,
Wiley Interscience (1972), 640 pp.
(15) Anon., "Mine Drainage and Acid Water Treatment", Coal Age, 76 (7),
pp 186-192 (1971). —
140
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REFERENCES (Continued)
(16) Hummer, E. D., "Refuse Removal and Disposal", Coal Preparation, (J. W.
Leonard and D. R. Mitchell, Editors), Third Edition, AIME, New York,
N.Y. (1968), Chapter 16.
(17) Anon., "Spray of Crusting Agent Puts Damper on Coal Pile", Coal Age,
26 (6), p. 110 (June, 1971).
(18) Public Law 94-850, The Resource Conservation and Recovery Act of 1976.
(19) U.S. Environmental Protection Agency, "Hazardous Waste Guidelines and
Regulations", Federal Register, 42^ (84), May 2, 1977.
(20) Personal communication between Alan S. Corson, U.S. Environmental
Protection Agency, and D. A. Sharp, Battelle's Columbus Laboratories.
(21) U.S. Environmental Protection Agency, "Thermal Processing and Land
Disposal of Solid Waste", Federal Register, August 14, 1974.
(22) Anderson, J. C., "Coal Waste Disposal to Eliminate Tailings Ponds",
Min. Cong. J., 61 (7), pp. 42-45 (1975).
(23) National Academy of Sciences, Underground Disposal of Coal Mine Waste,
report to the National Science Foundation, 1975.
(24) U.S. Bureau of Mines, "Methods and Costs of Coal Refuse Disposal and
Reclamation", 1C 8576 (1973).
(25) Rose, J. G., et al., "Composition and Properties of Refuse from
Kentucky Coal Preparation Plants", Proceedings of the Fifth Mineral
Waste Utilization Symposium, Chicago, Illinois, U.S. Bureau of Mines
(April, 1976).
(26) Maneval, D. R., "Recent Foreign and Domestic Experience in Coal Refuse
Utilization", First Symposium on Mine and Preparation Plant Refuse
Disposal, Louisville, Kentucky, National Coal Association (October, 1974).
(27) Pelczarski, E. A., et al., "Methods of Treating Coal Refuse", U.S. Patent
No. 3,917,795 (November, 1975).
(28) Robl, T. L., et al., "Kentucky Coal Refuse: A Geochemical Assessment
of its Potential as a Metals Source", Second Symposium on Coal Prepar-
ation, Louisville, Kentucky, National Coal Association (October, 1976).
141
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ENVIRONMENTAL ALTERNATIVES ANALYSIS
Environmental alternatives analysis is one of the most important
requirements in environmental impact assessment. However, it is also one
of the last activities undertaken in a program. Hence, Battelle's activity
in the first year in this area was limited to a preliminary pollutant ranking
(Subtask 241) and the modification of a computer model for evaluating
process technology (a segment of Subtasks 222 and 813).
Pollutant Ranking
When the initial group of approximately 1000 potential pollutants
from coal cleaning processes was identified, it was recognized that all
were not of equal importance and that priorities had to be established.
However, it was also recognized that attempts to rank them serially in
order would be a meaningless academic exercise. Thus, ranking efforts have
sought only to classify pollutants by priority groups. As described in an
earlier section, a Priority I group of about 75 pollutants regarded as most
important was selected as given by Table 6 in "Current Environmental
Background". The basis of selection of pollutants, which was not a rigorous
one, reflected such factors as toxicity, abundance, classification as a
named hazardous substance, and appearance in environmental standards.
For purposes of developing and testing an environmental assessment
methodology on actual substances, a "short Priority I list" of 12 pollutants
was drawn from the Priority I group as discussed in "Potential Pollutants and
Impacts in all Media" under the major heading "Current Environmental Back-
ground". However, no particular ranking significance is attached to this
list. Twelve was a convenient number to test, and the pollutants selected
possess a spread of characteristics desirable for testing. They do rank among
the most important pollutants and will rank high on any list of pollutants from
coal. Prioritization of pollutants, on a group basis, can be carried further
as more data on emissions and estimated permissible concentrations are developed.
142
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Modification of Computer Models for
Evaluating Process Technology
This work consisted of a modeling effort related to existing computer
programs in the area of coal preparation simulation. The purpose was to review
and modify this software to (1) aid in the evaluation of an advanced coal
cleaning facility being constructed at Homer City, Pennsylvania, and (2) use
in trade-off studies later in the Coal Cleaning Program. Four computer
programs were surveyed:
(1) A U.S. Bureau of Mines coal preparation plant simulation
model, version 4 (CPSM4), described in Gottfried, Jacobsen,
and Vaillant. ^
(2) A program to perform complete coal washability and
froth flotation calculations and to automatically
plot all washability curves, described in Humphreys,
(2)
Leonard, and Buttermore.
(3) Coal cleaning programs described by PEDCo-Environmental,
(3)
Inc. described in Isaacs.
(4) A computer simulation model for coal preparation plant
(4)
design and control, described in Walters.
Each of these programs contained unique features which hopefully will
be available at some future date in a single program. However, only the coal
preparation plant simulation model was sufficiently flexible to be directly
usable in the evaluation of the Homer City Plant. This program was, therefore,
selected for modification.
The original purpose for the modeling effort at the Bureau of Mines
that resulted in the construction of program CPSM4 was to give the user the
ability to simulate 'the performance of...configurations representative of
actual preparation plants'. The key word in the above purpose is representative.
The program was not originally designed to simulate actual plant conditions.
Rather, its role was to give users the ability to examine a representative
picture of some configuration as it might impact on a given type of coal.
143
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Such analysis is important and valuable for the various design tasks which
might precede the actual construction of a plant or, more importantly, which
might precede the very decision to build a plant.
With this purpose in mind, the authors of the program made every
effort to derive algorithms and generalized coefficients which would give
good generalizations of the behavior of the various types of equipment listed
in Figure 8. These algorithms included generalized distribution curves,
classification functions, selection for breakage functions, breakage distri-
butions, and others, all of which are discussed in detail in Goodman. This
work was very well formulated and programmed in the original version of the
program. It is a major asset to the design effort and all of it has been
maintained in the present version of the program, though in slightly different
form.
The goal of this research effort was not to simulate a representative
configuration; rather it was to simulate a particular plant - the Homer City
plant. Actual design curves describing the expected performance of units of
equipment in the plant were available. Eventually, actual performance curves
will also be made available after the plant becomes operational. The goal
set for the program was to generate results which agreed as closely as
possible with the material balance prepared by the design team for the plant.
To achieve this goal it was necessary to modify the program to deal not just
with generalized descriptions of equipment behavior but also with particular
descriptions - those used by the designers in preparing the material balance.
This basic modification was the purpose of the modeling effort which resulted
in the version of CPSM4 described herein.
Modifications Made to Program
The major goal of the initial modification effort was to restructure
CPSM4 so that it could be used in the evaluation of an actual coal cleaning
plant. In this context the term could be used was taken to have two levels of
144
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Unit Operation
Equipment Type
Blending
Splitting
Screening
Single-stage washing
Two-stage washing
Froth flotation
Rotary breaking
Crushing
Stream blender
Stream splitter
Dry upper screen
Dry lower screen
Wet upper screen
Wet lower screen
Concentrating table
Dense medium vessel
Dense medium cyclone
Hydrocyclone
Single-stage Baum jig
Classifying cyclone
Two-stage Baum jig
Froth flotation cell
Rotary breaker
Primary multiple roll crusher
Primary gyratory/jaw crusher
Primary single roll crusher
Primary cage mill crusher
Secondary multiple roll crusher
Secondary gyratory/jaw crusher
Secondary single roll crusher
Secondary cage mill crusher
FIGURE 8.. UNIT OPERATIONS SIMULATED
145
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meaning. In one sense, it was assumed that the program could be used for a
particular plant only if it could reproduce the performance, or expected per-
formance, of that plant. In this sense the utility of the program is measured
in terms of its predictive ability. In the other sense, it was assumed that
the program could be used for a particular plant only if the personnel asso-
ciated with that plant felt that they understood the mathematics of the
simulation and knew how to control it. The point here is that no matter what
the predictive ability of a program might be, it will not be used if the staff
who require its use either cannot control it or do not understand it.
The modification effort itself was divided in to five phases. The
overall purpose of the first phase was to make the program easily usable on
Battelle's Cyber 73 computer. In particular, three types of changes were
planned: (1) to reduce the core requirements of the program; (2) to simplify
the logic of the program; and (3) to develop a notation to aid in the
structuring of input to the program. As a result of this phase, the program
runs in 600000 words of core (versus 202000Q) and the processes of unit summar-
o o
ization, normalization, size bridging, etc., were unified into single routines.
Also, a block diagram notation was developed for describing plant configurations
which greatly simplified structuring the input to the program.
The second phase of the modification effort had as its goal to begin
making the program actually usable for the Homer City application. In parti-
cular, this phase was designed to modify the program so that it would accept
the actual washabilities that were used in designing the total cleaning plant.
As a result of the effort during this phase, the program was modified to accept
missing size-fraction data, to accept multiple input flows, and to accept a
much higher level of detail than the original version. At the end of this phase,
a set of runs was made for the Homer City plant and the results of and assump-
tions made in these runs were reviewed in great detail with the individuals
responsible for the design and operation of the plant.
The objective of the third phase in the modification effort was to
make any additional changes needed, as determined by the above review, to
make the results obtained from the program as representative as possible of
the expected performance of the plant. During this phase the size capabilities
were increased so as to allow for the simulation of the final plant configuration
146
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a provision was added allowing the program to accept Btu data classified both
by size and specific gravity; a capability was added to circumvent the gener-
alized distribution curves with actual curves; and various other miscellaneous
changes were made. At the end of this phase another review meeting was held.
At this meeting it was agreed that the present version of the program seemed
capable of representing the plant, and plans were made to make some data modi-
fications and to do extensive sensitivity runs.
The fourth phase effort for the program modifications started at the
beginning of the task and was completed with the preparation of a user handbook
by Goodman. Its purpose was to fully describe and document the program and
its logic so that it could be used as an effective and understandable tool.
Initially, a basic description of the mathematical approach to the program was
written and reviewed, then a detailed user handbook and program description
was written and distributed to the following along with a program deck and
sample data deck:
(1) Pennsylvania Electric Company, Johnstown, Pennsylvania
(2) New York State Electric and Gas Corporation, Binghamton,
New York
(3) Versar, Incorporated, Springfield, Maryland
(4) U.S. Bureau of Mines, Pittsburgh, Pennsylvania.
To date no serious problems have been reported by any of the above in their
attempts to make CPSM4 operational on their computers.
The fifth phase effort is not yet completed. Its purpose is to
modify CPSM4 to provide a tool to
(1) Evaluate effects of coal and equipment variables
on circuit and plant performances, and
(2) Compare alternative coal cleaning systems with
respect to environmental impact, energy recovery,
and cost.
Within this phase there are two major thrusts. The first is to incorporate
the calculation of costs into the program. At this point in time, a basic
set of cost estimation routines have been written and are being tested. In
addition, a working paper describing the overall approach has been distributed
for review and comment.
147
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The other thrust involves expanding the list of unit operations
within CPSM4 so that it can simulate not just coal preparation plants, but
also entire coal processing systems from mine to end-use. The types of
processes being studied include
(1) Mechanical dewatering
(2) Sedimentation
(3) Dissolved materials control
(4) Particulate control
(5) Gaseous removal and/or collection
(6) Storage, handling, and transportation
(7) Thermal drying
(8) End uses.
At this point in time, alternative approaches to simulating the above processes
are being examined. No actual implementations of these processes in CPSM4 have
begun.
Simulation of Homer City Plant
To date three input decks which relate to the Homer City plant have
been prepared, run, and reviewed. These are as follows:
(1) The initial plant configuration (for power plant
Units #1 and #2)
(2) The final plant configuration (for power plant Units
#1, #2, and #3)
(3) The material balance flowsheet.
By far the most important of these is the material balance flowsheet run.
Figure 9 shows the configuration and the results of the original material
balance prepared. Table 21 gives a comparison of results from CPSM4 with that
original material balance. The two results are quite close.
148
-------
TABLE 21. COMPARISON OF RESULTS FROM PROGRAM CPSM4 WITH ACTUAL
MATERIAL BALANCE - Prepared for Homer City Plant,
Units 1, 2, and 3
vo
Flow
Stream
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
20
19
22
23
28
29
30
31
32
% of
Actual
100.0
15.5
84.5
7.9
7.6
34.8
49.8
9.3
25.5
4.0
5.3
42.8
7.0
23.8
19.0
16.1
2.9
19.5
4.3
16.9
8.6
19.1
56.2
24.8
Feed
CPSM4
100.0
15.5
84.5
8.1
7.4
34.7
49.8
9.5
25.2
4.1
5.4
42.8
7.0
21.8
20.9
17.4
3.6
19.6
2.2
16.9
8.3
19.4
55.6
25.0
% Ash
Actual CPSM4
24.0
45.7
20.0
19.8
72.8
27.1
15.0
4.2
35.4
4.2
4.2
14.7
17.0
5.1
25.5
19.3
67.7
2.5
17.0
19.1
67.6
69.7
17.8
2.8
24.0
45.7
20.0
21.6
72.1
27.1
15.0
4.3
35.7
4.3
4.3
14.6
17.7
2.6
27.1
19.7
62.7
2.5
3.2
19.7
67.9
68.5
17.9
2.9
% Sulfur
Actual CPSM4
2.65
2.90
2.60
2.02
3.81
2.92
2.38
1.00
3.62
1.00
1.00
2.40
2.29
1.11
4.01
2.84
10.48
0.85
2.29
2.03
6.75
6.15
2.24
0.88
2.65
2.90
2.61
2.07
3.80
2.93
2.38
1.01
3.64
1.01
1.01
2.38
2.42
.85
3.98
2.86
9.37
0.85
0.86
2.10
6.76
6.11
2.24
0.88
Btu/lb
Actual CPSM4
11
7
12
12
2
10
13
14
9
14
14
13
12
14
10
12
3
15
12
12
3
3
12
15
,442
,599
,145
,187
.809
,898
,019
,970
,421
,970
,970
,071
,702
,804
,906
,272
,371
,262
,702
,309
,729
,367
,549
,200
11,452
7,596
12,160
11,881
2,932
10,899
13,040
14,944
9,377
14,944
14,944
13,118
12,561
15,243
10,904
12,211
4,594
15,254
15,141
12,202
3,663
3,555
12,523
15,187
RO?/MMBtu
Actual CPSM4
4.64
7.64
4.28
3.32
27.14
5.36
3.66
1.34
7.68
1.34
1.34
3.68
3.60
1.50
7.36
4.62
62.16
1.12
3.60
3.30
36.22
36.54
3.56
1.16
4.63
7.64
4.29
3.49
25.94
5.37
3.66
1.36
7.77
1.36
1.36
3.63
3.85
1.11
7.29
4.68
40.78
1.11
1.13
3.45
36.94
34.38
3.58
1.16
-------
Ln
O
1200 TPH"'!,!, 3107* /" \ Btu/hr to »3 Unit - 0.902 x I010 Feed rate -1200TPH 8tu/hr into pUnt - 2.746 x I010
IBB*-! I ^TJihV (• ' } etu/hr to *l «nd « Umtl • 1.682 « 10'° Reject rate • 229 TPH Btu/hr rejected • 154 « ID10
/.iilbi VMI«/ Total Btu/hr . 2.594 x 1010 Recovery rate - "I7TTPH Btu/hr recovery -O92x1010
10° Btu Wt. recovery -80.9% Btu recovery - 94.4%
f
1
7588 Btu/W
186 TPH - A* 46.72% f
2.80% Sul.- 3*2 fcS (~
10* Btu V
f
rit No 2 [^H.M.C. • 1.80 |
Sir* - 1.80
2 «» Btu/
B1TPH-A
3.81% Sul.
Unif No. 14
Unit No. 18 ,
Final Refine
Float -1 JO
12.187 Btu
86 TPH -A
2.02% Sul.
# VV
»h72.76%
-13.67 IbS
lO^Btu
r
1
f
Sink - 1
3.729 8
103 TPH
Ash 67 .f
Sul. 6.1
-18.
Ha* Coil Screens | Unit N«.l
1-1/4 » 1/4 f 1/4x0
B
11/4 x 2 MM
^ i
* 10.898 Btu/#
sh 1832% 417 JPH . Alh 27 ,Q% f 6 \
'•«6»>s 2-sHK Sul. - 2.6B IbS I. u J
106 BtU _ IfrSBtu V~X
1 H.M.C. S1.30 Unit No. 4
*
i
©Float -1.30 I *}
14.970 8tu/#- 111 TPH I c ]
Ash 4.19% ^*—/
Sir* - 1.30 Sul. 1.00%
9,421 Btu/# -0.67 IbS ,
306 TPH - Ash 35.41% 106 Btu '
3.62 Sul. " 3B4 fcS 3,371 Btu/#
to6 Btu 36 TPH - Aj
10.48% Sul.
Unit No. 5
i i
14.970 Btu/# /^I3\ 14.970 Btu fll\
48 TPH (— ' j 63 TPH t— - — j
Ash 4.19% V_!L^ Ash 4.19* V^X
1.00% Sul. 1.00% Sul.
- 0.67 Ib S = 0.67 Ib S
10* Btu '0* Btu (jrijts
(J ,) fJ No. 11.13 '
f \ m f \
. ., ... Units No 15, 16
[ H.M.c.euoJ Unit No. 17
I
^-^ i C™\ unit Na2°
/is\ 1 v c / "™
ao t-^ f v_y
u/« VJ_X Float -1.80
12.309 Btu/*
ss* s,,l 3rm.«l(SlhS Unit 3 Product
llbS 106 Btu 15.200 8tu/«
^ 1 SJ^
Sul. 0.88%
i Unit MQ 19 '°6B"/
3.367 Btu/#
229TPH x-
A« 89.89% L_f
Sul- 8.15% - 1837 IbS \^
106 Btu
Unit 1 & 2 Product AszA
12549 Btu/» I c )
-^ 674 TPH /7l\
«_\ Atfl ,,.75% (_1LJ
R! Sul. 2.24* VLx
— = 1.78 Ib S
106 B,U FIGURE 9 .
,
12.145 Btu/»
1014 TPH -Ash 19.98% fZ\
2.60* Sul. = 2. 14 IbS { ^~~J
106 Btu X
(
Deslime e> 2 MM
1
10.906
228 TP
Ash 26
1 Sul. 4.(
Unit No. 3
2MM«0
B,u/» (^
04% ^
K^Btu
| Hydro-Tables | Units NO. 8 "10
Reiect Unit 1 & 2 Product
(^\
\lx
(i 67.71%
» 31 OS Ih 5
10«Btu
12.272
193 TPt
Ash 19.
Sul. 2JJ
= 2.3
Btu/ff x — V
1 1 '9 I
26% V C ./
4% ^—^
1lbS
1fl6 Btu
- r
,
13,019 Btu/#
\ 597 TPH - Ash 15.01*
1 2.38% Sul. - 1.83 IbS
Id6 Btu
*
CvTJr «»H..S
Overflow | UnrHrllow
... . pt-\
12.702 Blu/« f^\ 13'071 Btu/*
84 TPH -Ash 1658% I 'R ) 513 TPH -A* 14.68%
Sul. 2J9%- I.80I6S V_X Sul. 2.40%" 134 fcS
I06 Btu 106 Btu
i
fi4"o. HJ..C. 1.30 | Unit No. 7
* /rr\
* ^viy
Sir* -1.30 /iT\ Flon-1.30
10W6 Btu/# I ' 1 14J04 8tu/#
228 TPH \^S && T»H
Ash 26.54% A* 5.07%
Sul. 4.01% Sul. 1.11%
•3.68 IbS -0.76 IbS
'0s Btu 10«8lu
I
V 1
r
12.702 Btu/'
51 TPH
Ash 16.98%
Sul. 2.29% -130
1
f
1 Spirel Classifier | Unit No. 12
100 Mesh | Unit 3 Product
S~^
( " } ?««ll5L.f°S.T_(?!!!.£!!!!
^ — ' «^ lucaiiiiv - ao5%
- - , — . Btu Recovery - 94.4%
Ih 5 15.262 Btu/* f' £2 \
— ; 234 TPH f )
10 8tu Ash 2 48% V^y
Sul. 0.85% = 0.56 Ib S
I06 Btu
MATERIAL BALANCE
-------
REFERENCES FOR ENVIRONMENTAL
ALTERNATIVES ANALYSIS SECTION
(pp. 142-150)
(1) Gottfried, B.S., Jacobsen, P.S., and Vaillant, A., "Computer Analysis of
Coal Plant Performance", presented at the 14th International Symposium
on the Application of Computer Methods in the Mineral Industries, the
Pennsylvania State University, Pittsburgh, Pennsylvania (October, 1976).
(2) Humphreys, K.K., Leonard, J.W., and Buttermore, J.A., "Computers for
Coal-Part X", Coal Age .
(3) Isaacs, G.A., Letter dated 10/5/76 containing output data from two coal
programs and a description of the cleaning plant configuration index
used, PEDCo-Environmental Specialists, Inc., Cincinnati, Ohio.
(4) Walters, A.D., "A Computer Simulation Model for Coal Preparation Plant
Design and Control", unpublished Master's of Engineering Thesis,
Pennsylvania State University, Department of Mineral Engineering, Pitts-
burgh, Pennsylvania, 1976.
(5) Goodman, F.K., "User Handbook for Coal Preparation Simulation Model
Version 4 (as Modified)", unpublished draft report for U.S. Environmental
Protection Agency, July, 1977.
151
-------
TECHNOLOGY TRANSFER
Contractual activities performed by Battelle-Columbus in this
area consist of (1) preparation of the Monthly Current Events Summary and a
quarterly Coal Cleaning Review, (2) the implementation, development, and
operation of a Coal Cleaning Information Center (CCIC), (3) support to the
Organization for Economic Cooperation and Development (OECD), (4) US-USSR
information exchange, and (5) evaluation of physical coal cleaning as an SC^
emission control strategy. The first two activities are described under
"Newsletter Status Reports" and "Information Centers", respectively. The
last three activities are described under "Other Reports".
Monthly Current Events Summary
The first issue of the Monthly Current Events Summary was included
in the monthly progress report for June, 1977. Subsequent issues of the
Summary have been included in the progress reports for July, August, and
September, 1977. It is planned that the preparation of the Monthly
Current Events Summary will continue throughout the current contract
period.
In brief, the Monthly Current Events Summary covers the following
topics.
(1) Calendar of meetings and short courses
(2) Annotated literature citations
(3) Organizational news
(4) New contract awards
(5) Requests for proposals
(6) Topics of general interest
Numerous journals, newsletters, reports, and other publications
are reviewed on a continuing basis to identify items of interest for inclu-
sion in the summary. It is planned that the calendar of meetings and
short courses and selected items from topics 2 through 6 above will be
utilized as imput to the Coal Cleaning Review (published quarterly).
152
-------
Coal Cleaning Review
The Fall, 1977, issue of the Coal Cleaning Review (the first issue)
is scheduled for completion by October 31, 1977.
The Coal Cleaning Review will provide descriptions of current
research results and new developments in (a) coal cleaning processes,
(b) related environmental effects, and (c) applicable pollution control
technology. It is expected that each review will contain several articles
which pertain to these three topics. In addition, the latest calendar of
meetings and short courses from the Monthly Current Events Summary and
pertinent items from various sections of all issues of the Summary during
the quarter will be included in the Coal Cleaning Review.
Information Centers
Coal Cleaning Information Center (CCIC)
The Coal Cleaning Information Center (CCIC) was implemented in
September, 1976. The most important functions and services of the CCIC
and the work accomplished during the past 13 months are summarized in the
following sections.
Data Base Development. Among the first tasks in establishing the CCIC
was that of data base development, which has been accomplished during the past
13 months through the following activities.
• The searching of commercial- and government-operated
data bases to identify citations of interest to the
coal cleaning program
• The screening of multiple information sources to
identify items of interest to the coal cleaning
program
153
-------
• The acquisition of articles and reports that were
identified through the screening process or which
have been brought to the attention of the CCIC by
project personnel
• The logging of new articles and reports, the assign-
ment of accession numbers, and the typing of a title
card and an input processing form for each item
• The review of each item being processed and the
selection of index terms for later use in computer
searching
• The keypunching onto tape, for each item being
processed, all information from the input process-
ing forms and all index terms which were selected
• The processing of tape into the CCIC computer data
base through the use of a computer program especially
prepared for this operation.
Contacting Organizations Conducting Ongoing Research. Searches of
the SSIE (Smithsonian Science Information Exchange) data base and one of the
ERDA/RECON data bases provided the material necessary for one of the important
activities of the CCIC during the past 13 months. The computer printouts
from these data base searches contained summary information of ongoing research
projects of interest to the coal cleaning program.
Telephone and letter contacts have been made with many of the organ-
izations conducting ongoing research to determine if research reports are
available to CCIC. A number of research reports have been obtained through
these contacts and, in a number of instances, Battelle has been placed on the
distribution for reports which are scheduled for publication in the future.
Document Storage and Retrieval. Data base storage has been accom-
plished through the processing into the computer of appropriate bibliographic
data and index terms for each item selected. As of September 30, 1977, there
had been approximately 900 items processed into the CCIC data base. The actual
hard copies of these 900 items are stored in the CCIC in accession number order
by year of processing.
154
-------
The identification and retrieval of items of interest are accom-
plished in two steps, i.e.:
(1) A search of the CCIC data base is conducted via
remote terminal. The search is made through the
use of appropriate index terms and all pertinent
citations are printed from the computer tapes.
(2) The computer printout lists all citations identified
through the computer search as being pertinent. An
examination of the printout will identify the most
important items and the hard copy of these can be
ordered from the CCIC holdings by referring to the
accession numbers listed on the printout.
Preparation of User Guide for Data Base Searching. In May, 1977,
a CCIC On-Line User Guide was prepared. This guide was prepared to instruct
the user in how to search the CCIC data base.
Detailed information was provided the user on log-in procedures,
query build-up, display of CCIC records, off-line printing, retrieval/
display aids and log-out procedures. In addition, tables were included
on searchable fields and output fields. An appendix included a Tymshare/
Tymnet communications network (including Tymnet telephone numbers) and an
abbreviated instruction page on the use of the CCIC data base.
After completion of the user guide, CCIC user names and passwords
were established for data base searching. Six user names and passwords
were forwarded to the EPA Project Officer and two user names and passwords
were retained for use by BCL project personnel. It is expected that the
EPA Project Officer will allocate CCIC user names and passwords for use
within EPA and to selected EPA contractors who would find it helpful to
search the CCIC holdings.
155
-------
Coordination and Preparation of Monthly and Quarterly Newsletters.
Monthly Current Events Summary. The monthly Current Events Summary
was initiated in June, 1977, and the first issue was included in the monthly
progress report for June, 1977. A more detailed description of the Monthly
Current Events Summary can be found in the section entitled "Newsletter Status
Reports".
Coal Cleaning Environmental Review. The preparation of the first
issue of the Coal Cleaning Environmental Review was started in September, 1977,
for publication as the Autumn, 1977, issue. Further details on the Coal
Cleaning Environmental Review can be found in the section entitled "Newsletter
Status Reports".
Other Reports Issued
Letter Report on "Desulfurization
of Coal" for OECD
A letter report, dated May 20, 1977, on "Desulfurization of Coal"
was prepared and submitted to the Organization for Economic Cooperation
and Development, Paris, France, for use in preparing a report for its 24
member countries on "Clean Fuel Supply".
In December, 1976, Battelle participated in a workshop on coal
desulfurization organized by OECD and held in Paris. The purpose of this
workshop was to initiate the preparation of a draft report on coal desul-
furization in western Europe and the United States.
Battelle's letter report was reviewed by the EPA Project Officer
prior to submission to OECD. The first draft of the OECD report on "Clean
Fuel Supply" was distributed for comments on September 8, 1977. Information
was provided in Battelle's May 20, 1977, letter report with respect to
the following six topics.
(1) Description of technologies available for
desulfurization of coal which can be used
between now and 1985
156
-------
(2) Estimates of capital and operating costs
versus plant capacity and quantity of sulfur
removal for these technologies for the U.S.
(3) Estimates of the time frame to construct and
shakedown coal desulfurization plants
(4) Estimates of the quantity of coal now being
desulfurized in the United States and the
quantity of sulfur being removed
(5) Estimates of the quantity of coal which could
be desulfurized in the United States and the
quantity of sulfur that would be removed in 1985
(6) Constraints preventing or delaying the use of
coal desulfurization technologies.
US-USSR Information Exchange
The exchange of information on coal utilization with the USSR began
about three years ago, shortly after 'the signing of the environmental agreement.
The information which has been exchanged has been in two general areas—coal
preparation and the use of coal in complex advanced energy generation systems.
Until the most recent meeting, the coal preparation activities have
been concerned primarily with the use of flotation for the removal of pyritic
sulfur. The transfer of that activity to the Energy Agreement led to a shift
in emphasis on coal preparation at the July, 1977, meeting in Moscow. The
activities now will focus upon the environmental consequences of coal prepar-
ation. It has been proposed that the initial activities be to conduct a
bilateral symposium on "Discharges and Controls for Coal Beneficiation Plants".
The USA and USSR delegations have met on two occasions during the
past year to pursue the exchange of information on the utilization of coal in
complex advanced energy generation systems—in the U.S. during December, 1976,
and in the USSR during July, 1977- The principal activity during both meetings
was the exchange of technical material which will be used in a joint report
which will be issued in 1978. The delegations will meet in November, 1977, and
twice in 1978 to finalize the joint report.
157
-------
Evaluation of Physical Coal Cleaning
as an S0? Emission Control Strategy
This effort has had two related but separate components. The first
objective was to provide a report to the Office of Air Quality Planning and
Standards (OAQPS) incorporating technical information on coal cleaning needed
by OAQPS in its evaluation of possible revisions in the New Source Performance
Standards (NSPS) for S0_ from utility boilers. The second component involves
a much broader effort to determine.the technological, environmental, institu-
tional, economic, and social factors which affect the adoption by industries
of physical coal cleaning (PCC) as an SO- emission control strategy, and to
analyze optional initiatives designed to overcome barriers to PCC commercial-
ization.
Report to OAQPS. The objectives of this portion of the task were:
to define available coal supplies by location and sulfur content for raw and
for physically-cleaned coal, to assess the impact of sulfur variability and
averaging times for determination of compliance on coal availability, to assess
the impact for alternative standards for utility boilers on coal markets and
supplies, and to describe existing and emerging technologies to abate SO
emissions from coal burning. A draft report was submitted June 30, 1977, and
a revised draft was completed October 14, 1977-
The analysis of coal availability under selected alternative NSPS
and control technique options was conducted in terms of years of coal avail-
ability assuming a constant utility demand. This is a useful way of showing
the effects of various NSPS and other factors on coal availability. The
utility demand for coal in 1985 was arbitrarily selected for this purpose.
Projections of coal use to 1985 are based on utility planning. While these
projections are not expected to be precise, they are more soundly based than
longer-range projections. If the utility coal use growth rate were essentially
constant, the 1985 projected demand would represent the average demand over
the next two decades. Changes in the demand rate chosen would affect the
years of availability (a higher demand would result in fewer years of coal
availability), but such changes would not affect the conclusions with respect
to the availability of raw coal or cleaned coal to meet selected NSPS.
158
-------
Federal Power Commission projections of coal demand for coal-fired
utility boilers call for 715 million kkg (788 million short tons) in 1985.
Given this projected utility demand for coal, the availability was determined
for various alternative NSPS and, for comparison, for the case of no emission
standards. The availability of coal which could meet the various NSPS with
coal cleaning together with flue gas desulfurization (FGD) also was determined.
The bounded solution to this analysis was obtained by using:
(1) The projected annual demand-pull of coal, by all
the coal-fired electric utilities (existing and
new) scheduled for 1985 operation;
(2) The annual coal demand by the potential utility
candidates for conversion from oil and gas to coal;
(3) The demonstrated recoverable coal reserve base;
(4) The potential cleanability of the reserve base;
(5) Assumptions regarding the effectiveness of FGD
applied to the combustion products from cleaned coal,
and
(6) Assumptions regarding the variability of sulfur in coal.
Summaries of the results of the analysis are displayed in the form
of bar charts in Figure 10, in which sulfur variability is not considered,
and in Figure 11, in which sulfur variability effects are included. The
bar chart is an effective means of conveying the effects of emission regula-
tions and techniques for compliance on the coal availability throughout the
United States.
The nature of the information presented in Figure 10 may be illus-
trated by reference to the four bars for the entire United States. If there
were no emission standards, the demonstrated recoverable coal reserve base
could supply the utility demand for 330 years if consumed at the projected
1985 rate. For a NSPS of 0.52 kg S02/GJ (1.2 Ib S02/106 Btu), raw coal
availability drops to 46 years. Physical cleaning to the level noted increases
the availability to 79 years'. If FGD and PCC were applied, the availability
becomes 326 years. This is almost the equivalent of the raw coal recoverable
reserve. This simply means that there is a small amount of coal which could
159
-------
500
400
300
u
HI
_l
CD
g 200
<
LU
>•
100
FIGURE 10.
COAL AVAILABILITY BAR CHART
STATUS OF THE AVAILABILITY OF COAL TO MEET THE NSPS OPTIONS
FOR ALL COAL-FIRED UTILITIES OPERATING IN 1985 (EXISTING PLUS NEW)
RAW AND PREPARED COAL WITH AND WITHOUT FLUE GAS DESULFURIZATION (FGD)
WESTERN REGION
THE ENTIRE
UNITED STATES
EASTERN-MIDWEST
REGION
EASTERN REGION
WESTERN-MIDWEST
REGION
555y
NO 1.2 0.8 0.4
NO 1.2 0.8 0.4 NO 1.2 0.8 0.4 NO 1.2 0.8 0.4
EMISSION STANDARD (SO2 Pounds Per Million Btu)
NO 1.2 0.8 0.4
-------
5001—
400
S 300
ui
LL
O
CO
*
in
200
100
THE ENTIRE
UNITED STATES
FIGURE 11.
COAL AVAILABILITY BAR CHART
STATUS OF THE AVAI LABI LITY OF COAL TO MEET THE NSPS OPTIONS
FOR ALL COAL-FIRED UTILITIES OPERATING IN 1985 (EXISTING PLUS NEW)
RAW AND PREPARED COAL WITH AND WITHOUT FLUE GAS DESULFURIZATION (FGD)
INCLUDING THE EFFECTS OF THE VARIABILITY OF THE SULFUR CONTENT OF COALS
THE RELATIVE STANDARD DEVIATION, RSD = 10%, COMPLIANCE = 99.87%
EASTERN-MIDWEST
REGION
WESTERN REGION
NO 1.2 0.8 0.4
I^vvXl Raw Coal
EASTERN REGION
WESTERN-MIDWEST
REGION
NO 1.2 0.8 0.4 NO 1.2 0.8 0.4 NO 1.2 0.8 0.4
EMISSION STANDARD (SO2 Pounds Per Million Btu)
NO 1.2 0.8 0.4
Prepared Coal (PCC)
>90% Btu Recovery, Crushed to 1-1/2" Top Size
FGD Combined with the Prepared Coal
90% Removal Efficiency, 100% of Gas Cleaned
-------
not meet a 0.52 kg/GJ (1.2 Ib S02/10 Btu) standard on a long-term averaging
basis even with PCC and FGD applied. For the optional 0.34 kg/GJ (0.8 Ib SC>2/
106 Btu) NSPS, raw coal and PCC coal availability both drop still further.
Essentially no raw coal or coal which could be sufficiently cleaned is avail-
able for the optional 0.17 kg S02/GJ (0.4 Ib S02/106 Btu) NSPS, and the
availability drops to 218 years even if both PCC and FGD control techniques
were applied. A regional breakdown also is presented in Figure 10. For each
region the available coal in the region is compared with the projected 1985
utility demand for coal in the same region.
All of the information presented in Figure 10 is based on average
sulfur values. Consideration of the effect of sulfur variability was incor-
porated in the analysis as summarized in Figure 11. The net effect of requiring
short-time averaging in determining compliance with a stated emission limit is
to reduce the availability of raw coal, and of cleaned coal as can be seen by
comparing Figure 11 with Figure 10.
The summary results of Figures 10 and 11 indicate the following
conclusions:
(1) PCC alone will be of limited value in meeting optional
NSPS for utilities.
(2) FGD or other control techniques with comparable sulfur-
removal effectiveness will be required, if more stringent
SO- emission standards are imposed.
(3) If the practicality of coal distribution from one region
to another region were ignored, and if it were assumed
that the coal reserves were available for use anywhere
in the United States, compliance with more stringent
regulations would still be impossible without FGD or
comparable control techniques.
(4) Since the potential for conversion from oil and gas to
coal would increase the demand-pull for coal by only
6 percent, this by itself would only cause a ripple
effect in the coal availability results.
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Initiatives Study. The second portion of the effort is directed
toward the identification of barriers to PCC commercialization and initiatives
for overcoming these barriers. The study involves: assembly of information
on coal supply, demand, reserves, and cleanability; review of coal cleaning
technology and costs; comparative analysis of alternative sulfur removal
options; review of environmental impacts of alternative sulfur removal
strategies; summary of air quality factors and emission control strategies;
identification of barriers; identification of initiative alternatives; assess-
ment of environmental, energy, and-economic trade-offs; and impact assessment.
Work is proceeding in all of these areas, however, completed results
are not available at this time. An interim progress report was submitted in
September, 1977, which included progress reports on the several areas under
study with respect to barriers and initiatives. A draft final report will be
issued in March, 1978.
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FUTURE EFFORTS
The following sections briefly describe Battelle's currently author-
ized and/or planned efforts for the remainder of the contract period ending
June 30, 1979.
Current Process Technology Background
Technology Overview - Subtask 211
The draft report entitled "Technology Overview of Coal Cleaning
Processes and Environmental Controls" will be revised to include information
on economics of coal cleaning, potential of coal cleaning technology for meeting
state implementation plans and regulations, limitations of washability data,
and other topics to be determined by EPA.
Revised Technology Overview - Subtask 291
The final report entitled "Technology Overview of Coal Cleaning
Processes and Environmental Controls", prepared on Subtask 211, will be revised
approximately during the last half year of the program to include updated
information obtained from both the outputs of other Subtasks of this program
and a continuing review of the literature.
Current Environmental Background
Develop Assessment Criteria - Subtask 241
Little further effort is anticipated on identifying additional
potential pollutants; however, some effort will be made in characterizing the
mode of occurrence and transformations of pollutants already identified.
An updated summary of pollution control regulations related to coal
cleaning processes will be prepared. This effort will involve revising
Appendix A to Battelle's April 8, 1977, preliminary report on "Development
of Environmental'Assessment Criteria" to include new regulations proposed and
promulgated since the report was submitted.
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The extent of further investigation and compilation of health/
epidemiological literature and dose/response data will depend upon the results
of the methodology development for estimated permissible concentrations. It
is expected that primary reliance will be on the MEG and MATE compilations, with
only limited investigation of a few specific substances, where additional data
may be needed.
Work on transport models will be continued and expanded; this will
include physical transport (including initial dispersion) and biological
transport. Initially, the models will be delineated for the 12 pollutants on
the "short Priority I list". The results from these efforts can be used to
extend the modeling to additional pollutants in the Priority I group.
Environmental Objectives Development
Develop Assessment Criteria - Subtask 241
The principal objective continues to be to develop an improved
methodology for estimating permissible environmental concentrations of pollutants
acceptable for the health and well-being of man on the basis of a long-term
continuous exposure. Various approaches to estimating permissible concen-
trations on the basis of toxicological data have been proposed, but none of
these appears to be adequate. Also necessary to this effort is a parallel
development of improved methods for interconverting and extrapolating a wide
variety of animal test results to man for use when the usual LD values for
the rat are absent.
It is clear from the work to date that development or synthesis of
the "best" method of extrapolation will be a difficult and complex task, and
perhaps one that cannot be completed during the present task investigation.
However, it is expected that the methodology presently being used can be signi-
ficantly improved.
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Environmental Data Acquisition
Development of Environmental Test Plan - Subtask 411
The report on this subtask has been submitted for review and all
that remains to be done is final revision following receipt of comments.
Selection of Evaluation Sites - Subtask 421
Upon approval of the site selection scheme, coal cleaning plants
will be classified into site categories. Information will be gathered on plant
characteristics from literature, government agencies, and site visits to make
site selections. Information on selected sites will be submitted for site
approval before field work begins. A total of ten sites will be recommended
as a prioritized list.
Development of Experimental Techniques - Subtask 431
Future effort on Subtask 431 will be to provide detail on those
experimental procedures to be implemented at the site investigations. The
detail will consist of work descriptions of procedures or reference to well-
known standards, flow charts showing the sequence of how samples may be
divided, and diagrams of equipment where appropriate. Quality assurance and
control aspects of Level I sampling and analysis will be addressed. Inade-
quacies in current practices of sampling and analysis, such as in the deter-
mination of leachable materials in refuse piles, will be indicated and
discussed.
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Test Support Development - Subtask 441
Appropriate equipment and instruments will be acquired as needed
to conduct the field and laboratory samplings and analyses in the field test
program.
Test Plan Development - Subtask 451
A master test plan, which is now being prepared, and which will
encompass the general requirements for testing all selected sites and coal
cleaning processes will be submitted. As individual evaluation sites are
selected, specific test plans will be prepared to add the details of sampling
location, kinds of samples, etc. that are unique to each site.
Testing - Subtask 461
As test sites are selected and approved, the field testing program
will be implemented. Sampling, testing, and laboratory analyses will be
carried out in accordance with the test plans prepared in Subtask 451 and the
analytical procedures outlined in Subtask 431. Testing is expected to begin
in the Fall of 1977 on sites of highest priority.
Data Reporting - Subtask 471
Data will be compiled, analyzed, and reported for each test site as
the programs at that site are completed.
Control Technology Assessment
Detailed Process Descriptions - Subtask 222*
In an effort to secure the previously defined additional information,
required to prepare the final report on "Pollution Control Technology for Coal
* Process Data Acquisition - Subtask 232 provides input data for this subtask
and is not reported separately.
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Cleaning Processes", visits are being conducted to vendors of pollution control
equipment, engineering consulting firms, and selected coal cleaning plants.
The types of information to be obtained from these visits and other sources are
summarized as follows:
• Dust emissions from transfer points (loading and
unloading) and access roads.
• Characteristics of process water from different
types of coal cleaning plants including total
suspended solids, pH, chemical composition, and
particle size distribution.
• Detailed material balances and performance charac-
teristics, including secondary pollution potential,
for existing pollution control equipment or
processes, e.g., ponds, thickeners, filters,
scrubbers, and cyclones.
• Detailed information on capital and operating
costs of pollution control equipment including
costs for power, water, labor, space, and material
requirements.
• Detailed capability and adaptability of new
pollution control equipment or processes.
• Process flow diagrams for treatment of runoff
from refuse and storage piles.
New Control Technology Studies - Subtask 271
Studies will be undertaken to generate preliminary conceptual designs
for improved pollution control systems for coal cleaning processes. This
task will utilize results from other subtasks including 211 (Technology Overview)
222 (Detailed Process Descriptions), 232 (Process Data Acquisition), 241
(Development of Assessment Criteria), 251 (Trade-Off Studies), and 461 (Testing).
Conceptual designs of control systems for air pollution, water
pollution, and solid waste will be developed. Advanced control technology will
168
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be examined for possible application to various types of coal cleaning processes,
The major emphasis will be on control technology for physical coal cleaning
processes, although control technology applicable to chemical coal cleaning
processes also will be addressed. Preliminary consideration will be given
to pollution control for biological coal cleaning processes.
Control Technology Development Status
Battelle-Columbus has no- planned contractual activities in this
area.
Environmental Alternatives Analysis
Detailed Process Descriptions - Subtask 222
Existing computer programs will be modified for utilization in
performing pollution control trade-off studies on Subtask 251. The major effort
in this area will involve further modifications to the U.S. Bureau of Mines
Coal Preparation Simulation Model Version 4 (CPSM4), as previously modified by
Battelle for use in evaluating the advanced coal cleaning facility at Homer
City, Pennsylvania.
The primary types of computer program modifications to be accom-
plished for the trade-off studies include providing the capability of (1)
modeling additional equipment types and/or operations, primarily related to
pollution control, coal handling, and end use, (2) analyzing capital and
operating costs for various configurations of coal cleaning plants including
pollution control systems, and (3) comparing alternative coal cleaning systems,
including various pollution control options, with respect to environmental
impact, energy recovery, and cost.
Pollution Control Trade-Off Studies - Subtask 251
Studies will be performed to establish cost and performance trade-
offs associated with various pollution control techniques for coal cleaning
processes (CCP). These studies will be used to identify the pollution control
169
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equipment and configurations which provide systems for minimal environmental
impact and/or minimal cost in coal cleaning plants.
Using information on existing and projected Federal and state regu-
lations for the control of pollutants from CCP, an assessment will be made
of the costs (energy and economic) and effectiveness of both existing and
recently developed applicable pollution control technologies. Capital and
operating costs, equipment life, maintenance requirements and performance will
be evaluated for each technology. This information will be integrated to
construct a cost-performance profile as a function of size for the various
control technologies.
Revised Process Descriptions and
Impact Assessments - Subtask 281
A detailed review will be made of information pertaining to perfor-
mance and costs of pollution control technology. Results from other subtasks,
including 251 (Pollution Control Trade-Off Studies), will be utilized to
revise and update process descriptions in the report entitled "Pollution
Control Technology for Coal Cleaning Processes", originally prepared on
Subtask 222. Emphasis will be placed on the relative advantages and disad-
vantages of each control technology and the trade-offs related to environmental
impact, costs, and energy utilization.
A comprehensive assessment of the environmental consequences of coal
cleaning processes will be provided. This environmental assessment will be
based on the assessment criteria developed on Subtask 241 and the field test
results from Subtask 461.
Technology Transfer
Coal Cleaning Information Center - Subtask 821
Newsletter Status Reports. It is planned that the preparation of
both the Monthly Current Events Summary and the Coal Cleaning Review (Quarterly)
will continue throughout the current contract period. Primary emphasis on the
Monthly Current Events Summary will be to include greater coverage through
the review of additional sources of information.
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Inputs to the Coal Cleaning Review will be solicited from other EPA
contractors who are performing research under the EPA coal cleaning program.
These inputs from other organizations should result in a newsletter much
broader in scope than that which was originally envisioned.
Information Centers. It is anticipated that the routine operations
of data base development, document storage and retrieval, and the contacting
of organizations conducting ongoing research, will continue throughout the
current contract period for the Coal Cleaning Information Center (CCIC). By
June 30, 1979, it is estimated that the CCIC data base will contain approxi-
mately 1,800 items of interest to the coal cleaning program.
In addition to the continuation of routine operations of CCIC during
future months, there is the possibility that two additional assignments will
be assumed by the CCIC. These new assignments, which were described within the
draft of Technical Directive (TD) No. C2-2 (822), dated May 18, 1977, are as
follows:
Annotated Bibliography. If funding is available in future'months,
it is possible that annotated bibliographies will be prepared for the EPA.
It is planned that these bibliographies will be printed from the CCIC data
base in alphabetical order by personal or corporate author.
In order to accomplish this task, considerably effort will be
required in adding selected annotations to the existing bibliographic infor-
mation within the CCIC data base and in making quarterly updates as suggested
in the May 18, 1977, TD. It will also be necessary to revise the present CCIC
computer program so that the annotated bibliographies can be printed in the
manner desired.
Reference Services. When resources are available, the service of both
manual and computer searches of the CCIC data base as well as computer searches
of commercial- and government-operated data bases can be made available to EPA
and to selected EPA contractors.
Remote terminal access to the CCIC data base is already possible by
EPA and EPA contractors as described in the CCIC On-Line User Guide. Assign-
ments to perform searches of commercial- and government-operated data bases
could be accepted by CCIC if directed by EPA.
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Coal Cleaning Demo Planning - Subtask 813
The U.S. Bureau of Mines CPSM4 program, as modified by Battelle,
will be used in the evaluation of the Homer City coal cleaning plant. The
following types of tasks are envisioned in this effort.
(1) Adjust the equipment specifications for the Homer
City configurations as input to program CPSM4 to
obtain agreement with experimental results obtained
during the plant performance testing and any process
characterization studies which might be performed.
(2) Using data obtained from equipment performance tests
which will be conducted to measure the sensitivity
of that performance to coal properties and operating
variables, further adjust program CPSM4 and/or its
input data to achieve agreement with these results.
(3) Perform trade-off studies using CPSM4 to identify
changes in operating conditions and coal blends which
will maximize Btu recovery and pyritic sulfur removal
and which can be used to operate the plant for extended
periods of time.
(4) Incorporate changes into CPSM4 which would allow the
program to estimate detailed coal washability data
given only a limited number of experimental data
values (probably about 20 points).
(5) Using a newly developed cost model within CPSM4 and
available cost data, incorporate a cost component
into the trade-off studies.
US-USSR Information Exchange - Subtask 841
Meetings of US-USSR delegations are anticipated in November, 1977
and twice during 1978 to finalize a joint report on the utilization of coal
in complex advanced energy generation systems.
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Evaluation of Physical Coal Cleaning as
an SOp Emission Control Strategy - Subtask 851
Work on this task is scheduled to be completed with revision of the
draft report on "Initiatives Study" due December, 1977. Some discussions have
been conducted regarding additional modeling work required after completion of
this effort, however, no work has been directed, and none has been incorporated
in future planning at this time.
Symposium on Coal Cleaning to Achieve
Energy and Environmental Goals - Subtask 861
A symposium on the environmental aspects of coal preparation will
be planned and held.
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/7-79-073C
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE Environmental Assessment of Coal
Cleaning Processes: First Annual Report; Volume n.
Detailed Report
5. REPORT DATE
June 1979
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
A. W. Lemmon, Jr., S. E. Rogers, G, L. Robinson,
V. Q. Hale, and G. E. Raines
8. PERFORMING ORGANIZATION REPORT NO.
). PERFORMING ORGANIZATION NAME AND ADDRESS
Battelle-Columbus Laboratories
505 King Avenue
Columbus, Ohio 43201
10. PROGRAM ELEMENT NO.
E HE 62 3 A
11. CONTRACT/GRANT NO.
68-02-2163, Task 11
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PER
Annual; 7/76 - 9/77
ERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTESIERL..RTp project officer is James D. Kilgroe, Mail Drop 61, 919/
541-2851.
16. ABSTRACT
report gives results of the first year's work on an environmental
assessment of coal cleaning processes. A strong base of engineering, ecological,
pollution control, and cost data is being established through data gathering and sys-
tems analysis efforts. In addition to program management, three task areas are
defined: system studies, data acquisition, and general program support. Early avail-
ability is anticipated for draft reports of progress for three subtasks : (a) developing
information on on coal cleaning process technology; (b) defining the technological and
cost status of the control of pollutants from coal cleaning and refusal disposal; and
(c) establishing criteria for meeting environmental goals. (A fourth subtask, acqui-
ring process data, was terminated to avoid duplication.) Progress has been made on
data acquisition subtasks, aimed at the planning needed as the forerunner of the anti-
cipated environmental field testing program: (a) developing and describing the overall
environmental test program; (b) developing the rationale for selection and selecting
the evaluation sites; (c) specifying the experimental testing techniques to be used;
and (d) developing the master site test plan. (Ten site categories have been specified
for testing. ) General program support includes : (a) obtaining background environmen-
tal data, and (b) operating a coal cleaning information center.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Pollution
Assessments
Coal Preparation
Waste Disposal
Mathematical Models
Emission
Sulfur
Sulfur Oxides
Pollution Control
Stationary Sources
Environmental Assess-
ment
13B
14B
081
12A
07B
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
185
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
174
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