PB85-116853
i-'e thuds/Materials Matrix of
Ultimate Disposal Techniques for
Spilled Hazardous Materials
Battelle Pacific ttorthwest Labs., Richland, WA
Prepared fee
Municipal Environmental Research Lab.
Cincinnati, OH
Oct
Ll Uj LJwrin'
U.S.
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EB85-116B53
EPA-600/2-84-170
October 3984
METHODS/MATER I PL S 1iATRIX
OF ULTIMATE DISPOSAL TECHNIQUES FOR
SPILLED HAZARDOUS MATERIALS
t>y
B. W. Mercer
G. W. Dawson
i). A. McNeese
E. G. Baker
Battelle Pacific Northwest Laboratories
Battelle Memorial Institute
Richland, Washington 99352
Contract No. 63-03-2494
Project Qff-'-.fr
John E. Brugqer
Oil and Hazardous Materials Spills Branch
Municipal and Environmental Research Laboratory - Cincinnati
Edison, New Jersey Oc837
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
KWOOUCCD 8V
NATIONAL TECHNICAL
INFORMATION SERVICE
U.S. OtP»SIBfNI OF COWMfRCf
. HL 22161
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TECHNICAL REPORT DATA
c nu RtPOHT DATc
October 1934 _ _
PtRIORMINGGHGANIZATIGNCODE
AUTHOFU3)
0. PERI ORMING ORGANIZATION Rl.POHT NO.
B.W. Mercer, G.W. Dawson,
J.A. McNeese, 6 d E.G. Baciated with each of these isposai methods
are discussea. Special emphasis is given tc spills of highly toxic ano persistent
hazardous materials.
An annotated matrix was prepared to provide a full assessment of conventional
dispcsai options for eacn class of hazardous material and for mixtures thereof. The
Hazardous materials are qroupeo according to physical/chemical properties and placed i
juxtaposition with the form (liquid, sludge) or composition of the spill residue
containing the hazardous material (e.g., mixtures with water, grass, sand, debris,
etc.). The disposal options are priority-ranged for each given set of conditions. The
annotation de-scribes each disposal option and evaluates the influence of spil1-situatio
parameters on the disposal method with regard to effectiveness, cost, safety,
availability c>f equipment and materials, and short and long-term hazards.
Deficiencies in conventional disposal methods, such as secured landfills, are
identified. An amended matrix, which supplements the matrix based solely on
conventional methods, includes novel disposal methods that show strong potential for
filling some of the gaps in existing disposal technology.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
h.lDENTII IERS/GPEN ENDED TERMS
COi.ATI I u;IJ/(.;roup
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19 SECURITY CLASS (Tim Report)
UNCLASSIFIED
20 SECUR~lTY~CLAl>b tThis~pa>
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DISCLAIMER
The information in this document has been funded wholly or in part by
the United States Environmental Protection Agency under Contract No.
68-03-2494 to Battelle Pacific Northwest Laboratories. It has been
subject to the Agency's peer and -idministrative review, and it has been
approved for publication as an EP/. document. Mention of trade names or
commercial products does not constitute endorsement or recommendation for
use.
CAUTIONARY MOTE TO READER
This study was conducted during the late 1970's and contains dated
information pertaining to U.S. Environmental Protection Agency regulations
and policies. Consequently, the reader is reminded to retain the same
perspective that would be appropriate in reading any document several
years after its initial preparation. Particular care should be exercised
when considering the cost data and references to "current and anticipated"
regulations and Agency policies, many of which have now become much more
demanding. It was decided to publish this report, even though portions
are out of date, based on the potential benefits that could be derived
from the technical content of the study.
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FOREWORD
The U. S. Environmental Protection Agency was created because of
increasing public and Government concern about the dangers of pollution to
the health and welfare of the American people. Noxious air, foul water,
and spoiled land are tragic testimonies to the deterioration of our natural
environment. The complexity of that environment and the interplay of its
components require a concentrated anu integrated attack on the problem.
Research and development is that necessary first step in problem
solution; it involves defining the problem, measuring its impact, and
searching for solutions. The Municipal Environmental Research Laboratory
develops new and improved technology and systems to prevent, treat, and
manage wastewater and solid and hazardous waste pollutant discharges from
municipal and community sources, to preserve and treat public drinking
water supplies, and to minimize the adverse economic, social, health, and
aesthetic effects of pollution. This publication is one of the products of
that research and provides a most vital communications link between the
researcher and the user community.
This study was undertaken to evaluate conventional and novel methods
for ultimate disposal of spilled hazardous materials. Disposal methods
studied include incineration, pyrolysis, landfilling, fixation, biological
treatment, and chemical treatment. Applications of these disposal methods
to spilled hazardous material residues is discussed with special emphasis
given to spills and releases of highly toxic and persistent hazardous
substances. The problems related to disposal of mixtures of hazardous
materials with other substances such as processing sludges, soil, debris,
and various aqueous inorganic and organic dilutents is also discussed. The
report contains information that can be used by on-scene coordinators, as
well as by waste generators and haulers, the hazardous waste disposal
industry, and environmentalists who seek a better understanding of waste
disposal options.
Francis T. Mayo, Director
Municipal Environmental Research Laboratory
m
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ABSTRACT
Conventional and novel methods for the ultimate disposal of spilled
or released hazardous substances are evaluated. Disposal methods reviewed
include incineration, pyrolysis, landfilling, fixation, biological treatment,
and chemical treatment. Applications of these disposal methods to hazardous
material residues is discussed with special emphasis given to spills or
releases of highly toxic and persistent hazardous materials. The problems
related to disposal of mixtures of hazardous materials with other substances
such as processing sludges, soil, debris, and various aqueous and organic
dilutents is also discussed.
An annotated matrix was prepared to provide a full assessment of
conventional disposal options for each class of hazardous material and for
mixtures thereof. The hazardous substances are grouped according to
physical/chemical properties and put in juxtaposition with the forr, of the
spill or release residue containing the hazardous material (P.9., mixtures
with water, grass, sand, debris, etc.). The disposal options are priority-
ranked for each given set of conditions. The annotation describes each
disposal option and evaluates th^ influence of spill-situation parameters
on the disposal method witr, regard to effectiveness, cost, safety,
availability of equipment and materials, and short-and long-term hazards.
Deficiencies in conventional disposal methods are identified. An amended
matrix which supplements the matrix based on conventional methods
includes novel disposal methods that show strong potential for filling
some of the gaps in existing disposal technology.
Maximal use of hazardous waste management facilities located
throughout the United States is recommended for disposal of spill and
release residuals. These facilities, including secured landfills, will
soon be operating under the stringent regulations mandated by the Resource
Conservation and Recovery Act, and will therefore provide greater
assur?nce of adequate containment or disposal of hazardous wastes.
This report was submitted in fulfillment of Contract No. 68-03-2494
by Battelle Pacific Northwest Laboratories under the sponsorship of the
U.S. Environmental Protection Agency. This report covers the period from
February 1977 to July 1980, and work was completed as of September 1982.
IV
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CONTENTS
FOREWORD iii
ABSTRACT iv
LIST OF FIGURES viii
LIST OF TABLES ix
ACKNOWLEDGMENTS x
1. INTRODUCTION 1-1
2. SUMMARY AND CONCLUSIONS 2-1
3. RECOMMENDATIONS 3-1
4. REVIEW OF REPORTED SPILLS 4-1
SPILL OCCURRENCES 4-1
Types of Material 4-1
Frequency of Spillage 4-1
DISPOSAL OF SPILL RESIDUALS 4-1
Methods Used 4-1
Disposal Problems Encountered 4-3
5. DESCRIPTION AND ASSESSMENT OF CONVENTIONAL DISPOSAL
ALTERNATIVES 5-1
BIOLOGICAL TREATMENT ..... , 5-1
General Description 5-1
Activated Sludge Process ..... 5-3
Trickling Filter 5-5
Waste Treatment Lagoon 5-7
Land Application Assessment of Biological Methods . . 5-8
Assessment of Biological Methods 5-9
Il.CINERATION 5-10
General Description 5-10
Types of Incinerators 5-11
Pyrolysis 5-19
Hazardous Waste Incineration 5-19
Assessment 5-24
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CONTENTS (contd]
NEUTRALIZATION 5-26
Description of Process 5-26
Assessment 5-27
PRECIPITATION 5-28
Description of Process 5-28
Assessment 5-29
CHEMICAL OXIDATION AND REDUCTION 5-30
Description of Process 5-30
Assessment 5-31
LOW TEMPERATURE FIXATION 5-31
Description of Process 5-31
Assessment 5-33
SANITARY LANDFILL . 5-33
Description of Process ..... 5-33
Assessment 5-34
SECURE LANDFILL 5-35
Description of Process 5-35
Assessment 5-36
DEEP-WELL DISPOSAL . 5-33
Description of Process 5-38
Assessment 5-40
OCEAN DISPOSAL 5-41
Description 5-41
Assessment 5-41
APPLICATION OF CONVENTIONAL DISPOSAL TECHNOLOGY 5-42
Spill Characteristics 5-42
Method Evaluation Matrix 5-43
vi
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CONTENTS (coritd)
6. THE HAZARDOUS WASTE PROCESSING INDUSTRY 6-1
7. NOVEL DISPOSAL METHODS 7-1
THERMAL DESTRUCTION . 7-1
Cement Kilns 7-1
Molten Salt Incineration 7-1
CHEMICAL DESTRUCTION 7-2
Brominaticn Process ... 7-2
Sodium Reduction Process . 7-4
BIOCHEMICAL DESTRUCTION ... 7-4
MICROWAVE DESTRUCTION . 7-4
ADVANCED FIXATION METHODS . 7-5
APPLICATION OF NOVEL DISPOSAL TECHNIQUES ...... 7-5
Need for New Disposal Methods 7-5
Modified Evaluation Matrix . 7-6
8. IMPACT OF REGULATIONS FROM RESOURCE CONSERVATION AND
RECOVERY ACT 8-1
REFERFflCES .............. Ref-1
APPENDIX A A-l
APPENDIX B B-l
VTl
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FIGURES
Number Page
1. Activated Sludge Process 5-4
2. Trickling Filter Diagram 5-6
3. Multiple Hearth Incinerator 5-13
4, Rotary Kiln Incinerator 5-14
5. Fluiciized Bed Incinerator 5-15
6. Diagram of Horizontal Liquid Waste Incinerator .... 5-17
7. Thermal Vortex Bu-ner 5-21
8. Location of Hazardous Vvaste Incinerators
in the United States ..... 5-23
9. Example of a Secure Landfill 5-37
10. Location of Secure Landfills in the United States . . . 5-39
11. Geographic Distribution of Hazardous Waste Management
Facilities 6-3
12. Flowsheet for Bromination Process for Destruction of
Hazardous Organic Materials 7-3
B-l. Diagram of a Horizontal Liquid Waste Incinerator . . . B-3
B-2. Typical Vertically Fired Liquid Waste Incinerator . . . B-5
B-3. Flow Diagram for Sludge Disposal by Fluidized Bed . . . B-6
Incineration
B-4. Catalytic Incinerator With Heat Recovery B-12
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TABLES
Number Page
1 Disposal Methods Employed for Hazardous Spill Residuals 4-2
2 Processing Capabilities of Five Types of Commonly Used
Incinerators 5-25
3 Matrix for Conventional Disposal Methods 5-44
4 Amended Matrix for Novel Disposal Methods 7-7
Also Tables in Appendix B
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ACKNOWLEDGEMENTS
The authors gratefully acknowledge the support and advice provided by
Or. John E. Brugger of the Municipal Environmental Research Laboratory,
Oil and Hazardous Materials Spills Branch, Edison, New Jersey. The
authors also wisr, to fiank the following Battelle personnel who
participated in the tasks of typing and proofreading of the manuscript:
Barbara Roberts, Mary Heid, Darla Kennedy, Marianna Cross, and Nancy
Painter. Dr. H. Skovronek, consultant to IT Corporation, prepared the
separately issued Project Summary Report. Mr. Gregory N. Bailey, MERL-OHMS
Branch, Ms. Darlene Williams and Ms. Joanne Cuoghi, IT Corporation,
proofread and retyped the Project Summary Report and the final manuscript.
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SECTION 1
INTRODUCTION
With promulgation cf the regulations on Hazardous Substance Spills
(Section 311 of PL 92-500 the Clean Water Act, as amended), increased
effort will be directed to the cleanup and collection of spilled and
released materials and the volume of contaminated spill residuals
requiring disposal will commeasurately increase. At the same time,
regulations mandated by the Resource Conservation and Recovery Act
(PL 94-580) will dictate the manner in which that disposal may be
conducted. Consequently, much more scrutiny will be placed on spill
residual management.
Cleanup activities following spills or releases of hazardous materials
or wastes frequently involve the disposal of extraneous matter such as
soil, sediment, water, and debris that has become contaminated by the
hazardous substance. Disposal methods normally used for the hazardous
material alone may no longer be fully applicable in these cases. For
example, the recommended disposal method for PCB's is incineration at
12003C with 3% excess oxygen and a dwell time of 2 seconds or at
160QQ C with 2% excess oxygen and a dwell time of 1.5 seconds. (1)
Under these conditions destruction of PCB's in a relatively pure form or
diluted with an appropriate solvent is a practical, proven disposal
method, whereas destruction by incineration of small amounts of PCB's
intermixed with large quantities of sediments is not as practical. An
alternate disposal method that is consistent witli good environmental
protection practices must be selected for this mixture.
The preceding example addresses a single substance and a single
technology. Disposal of spill residuals from over 650 designated
Hazardous materials(2-4) can involve a wide variety of pretreatmen-t and
disposal methods ranging from a simple water flush to complex chemical
treatment followed by burial of any residuals in a secure landfill.
Further, spills and releases need not consist of a single pure substance.
In addition to tne 650 designated hazardous substances spills may involve
numerous mixtures containing these substances in the form of industrial
process streams and liquid and solid wastes (RCRA wastes). Spillage of
either discrete hazardous materials or process streams and wastes
containing these materials can create a waste form with properties that
are substantially different than those of the original material. Chromium
sulfate solution spilled on soil, for example, becomes much less of a
threat to aquatic life than the original solution spilled in a stream
oecause the soil ties up the chromium ion, thereby reducing its
availability by leaching to aquatic life forms. Indeed, the chromium may
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be so diluted and so tightly held by the soil that the soil mixture would
not qualify as a hazardous waste and could safely be disposed in a
sanitary landfill instead of in a secure landfill as would be the case for
nearly pure chromium sulfate.
Heretofore, mixtures of hazardous materials with extraneous matter
have been largely dealt with on a judgmental basis since no uniform
criteria were available to classify mixtures. Hence, considerations such
as those discussed above were performed on an £d_ hoc basis. However,
EPA's Office of Solid Waste is currently developing criteria for
designating hazardous wastes that should simplify tie problem of
classifying mixtures of hazardous material with inert matter. Clean-up
debris from spills of designated hazardous materials will be defined
generically as hazardous wastes. For other spill residuals, a significant
element of these criteria will be a leach test to determine the
availability or mooility of hazardous substances in the mixture
(EP-toxicity test, 40 CFR 261.24). Consequently, spills of hazardous
material have the potential of creating a hazardous waste which, under
impending regulations, must be disposed of by an authorized method. In
tne case of small spills of hazardous materials not specifically cited in
the RCRA regulations, tests (ignitibi1ity, corrosivity, EP-toxicity,
reactivity) to classify spill residual mixtures may not be economically
justified if--for example—the cost of burial in a secure landfill is less
than the combined costs of the tests and burial in an ordinary sanitary
landfill. For spills involving large quantities of spill residual
mixtures, conducting the tests could save substantial disposal costs.
The following discussion is directed to a description of the
capability of current technology to cope with spill residuals management.
Special emphasis is placed on identifying gaps in that technology and on
specifying alternatives that may fill these gaps.
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SECTION 2
SUMMARY AMD CONCLUSIONS
Conventional technology is considered satisfactory for the ultimate
disposal of the majority oT waste residuals resulting from hazardous
spills and releases. Hazardous materials exhibiting low toxicity and
persistance generally do not represent a disposal problem; however,
continued effort is needed to assure use of the proper method in each
spill situation. Maximal use of hazardous waste management facilities
located throughout the nation is recommended for disposal of spill
residuals. These facilities are more likely to have the special equipment
and staff expertise needed to dispose of the residuals than are sewage
treatment or industrial waste treatment plants. Furthermore, the
hazardous waste disposal industry will soon be operating with permits
granted through regulations mandated by the Resource Conservation and
Recovery Act. As such, selection of a firm that has been granted a permit
carries some degree of assurance the proper disposal practices will be
employed. The need for effective disposal has now been enhanced
significantly by the passage of CERCLA ("Superfund") legislation
(PiL. 96-510.)
Areas where conventional technology is considered inadequate include
the disposal of highly toxic and persistent spill residuals intermixed
with extraneous matter including soil, sediments and debris.
Incinerators, for example, are generally not practical for economically
decomposing organic substances intermixed with substantial quantities of
noncombustible material such as soil. An effective leaching technique is
a potential alternative for recovering the residual for disposal.
Currently, research is planned to evaluate the effectiveness of leaching
(or solvent extraction) over a range of different materials and conditions.
The EPA's Oil and Hazardous Materials Spills Branch in Edison, New Jersey,
is currently sponsoring several research programs to develop alternate
methods of decomposing and detoxifying hazardous organic substances such
as persistent chlorinated hydrocarbon pesticides. The methods under
investigation include: 1) degradation by liquid alkali metals,
2) biological degradation with specially adapted microbial cultures, and
3) decomposition through oxidation by bromine (with recovery of Br2 from
HBr). These methods are aimed at the disposal of small quantities of
highly toxic material which may or may not be mixed with large quantities
of extraneous matter.
The lack of suitable incinerators and public objection to their
siting in many areas of the country are other problems associated with the
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destruction of hazardous organics. In addition to the chemical and
biological techniques identified above, incineration in ce ient kilns and
microwave or plasma arc decomposition show potential for destruction of
highly toxic organics.
The disposal of highly toxic heavy metals such as cadmium and arsenic
pose a special problem since these substances cannot be decomposed as in
the case of organic materials where the toxicity is dependent on structure
rather than on elemental composition. One potential alternative is
incorporation of these metals in a matrix such as glass that has a very
low leaching rate. Fixations of heavy metals can effectively minimize the
mobility of toxic heavy metals when a sufficiently low leach rate can be
maintained over an indefinite (but long) time period. Fixation in glass,
although higher in cost than other chemical waste fixation methods, is a
leaching candidate for achieving long-term stability with low leach rates.
Fixation in other matrixes (e.g. asphalt, plastics, cement-like compositions,
synthetic rocks) are other alternatives.
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SECTION 3
RECOMMENDATIONS
The continued development and demons;ration ot novel disposal methods
are recommended to overcome current deficiencies in conventional
technology and the lack of adequate dispo-al facilities in sufficiently
remote and controlled access areas. This effort should focus on methods
that achieve near-total destruction of hazardous organic materials and
permanent containment of highly toxic metals. Landfill disposal of highly
toxic persistent hazardous materials should be phased out as the primary
containment method for these materials since the long-term integrity of
most landfills cannot be assured (or "insured", as may be required under
"Superfund" regulations).
Incineration is the standard technique for destruction of hazardous
organic materials. However, facilities properly designed to accomplish
this task are not widely available. Current efforts to demonstrate the
use of cement kilns, smelters, blast furnaces, and other large processing
units for destruction of these wastes should bo intensified. Since cement
kilns, for example, cannot accept all waste forms, some attention should
be directed to development of mobile facilities to modify residuals to
acceptable forms, thus extending the applicability of kilns. In addition,
alternate methods for chemical destruction should be demonstrated to
provide coverage in areas where incinerator facilities are not available.
These alternate chemical disposal units should be equipped to destroy the
highly-toxic persistent spill residuals that are usually transported in
small shipping containers, such as drums, as opposed to bulk shipping in
tank cars. The disposal units may, therefore, be relatively small in size
to allow transport to the spill site or they may be constructed from
locally available equipment and materials. These units should also be
equipped to handle debris that is intermixed with the spill or release
residual. Studies are currently being conducted under EPA sponsorship to
evaluate oxiaation by bromination, reduction with elemental sodium, and
biochemical degradation with specific cultures to dispose of hazardous
organic spill residuals. Methods of leaching spill residues from debris
are also being developed under EPA sponsorship and rapid implementation of
these methods will greatly aid in recovery and disposal efforts.
Much more work is needed to demonstrate adequate fixation methods for
the highly toxic metals. Fixation should be sufficiently "tight" to
ensure that the leach rate is low enough to avoid the presence of toxic
levels of these metals in the leachate. Furthermore, the fixed waste
should exhibit essentially permanent stability under anticipated
environmental conditions (e.g., weathering, leaching, land use). Fixation
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in glass is presently being investigated as a potential method for
containment of toxic heavy metals (many radionuclides have been
successfully bound in glassy matrixes).
The need to upgrade and actively involve the hazardous v;aste
management industry for disposal of hazardous spill residuals should be
emphasized by EPA and state representatives who are responsible for
cleanup activities following a spill. An up-to-date listing of hazardous
waste disposal facilities in each region should be maintained and made
available to personnel responding to spills of hazardous materials.
Further, efforts should be made to pnsure that response personnel are
familiar with emerging hazardous waste regulations since these will
prescribe legal constraints on the management of spill residuals.
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SECTION 4
REVIEW OF REPORTED SPILLS
Information concerning recent spills and releases of hazardous
materials in the United States was reviewed to determine the current
frequency of these events, the countermeasures taken, the types of
problems encountered, and the disposal methods used for spill residuals.
SPILL OCCURRENCES
Types of Material
Substances designated as hazardous materials (for the purposes of
this project) are listed in alphabetical order in Appendix A. This list
was compiled'from the Environmental Protection Agency's list of Hazardous
Substances,(?) the U.S. Coast Guard's CHRIS Hazardous Chemical Data(3)
and pesticide data.(4) in addition to the materials included in
Appendix A, mixtures of these same materials and wastes designated as
hazardous under RCRA regulations^) are also considered to be hazardous
materials. Industrial wastes consisting of sluoqes, off-spec materials,
residues, bottoms, etc. which contain varying concentrations of hazardous
substances are typical examples or mixtures from manufacturing and
processing operations. Debris that becomes contaminated with spilled
hazardous material is another type of mixture that may be a hazardous
waste. Consultation with private firms whose business is cleaning up
hazardous material spills reveal that contaminated soil or sediments were
the most frequently encountered contaminated debris.
Frequency of Spillage
Approximately 13,000 spills of oil and hazardous materials occur in
waterways of the United States each year.(6) over 60% of the reported
spills involve oil substances for which mandatory reporting requirements
have been in effect since 1970. It has been estimated that 3000 spills of
hazardous materials excluding oil enter the nation's navigable waters each
year.(8) Land spills that do not directly threaten water are not
covered under PL 92-500 (Clean Water Act) but may be covered under RCRA,
CERCLA ("Superfund") or the Clean Air Act.
DISPOSAL OF SPILL RESIDUALS
Methods Used
A survey of waste disposal firms disclosed that landfilling is the
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most common method used for disposing of oil spill residuals that cannot
be recovered for re-use. A review of 78 randomly selected, hazardous
material spill reports received by the Oil and Hazardous Materials Spill
Branch of the EPA's Municipal Environmental Research Laboratory at Edison,
New Jersey, during the period December 1975 to May 1977 reveals that no
action for spill cleanup occurs in 36% of the spill events. This is
followed by the use of a water wash in 24% of the events as shown in
Table 1.
TABLE 1. Disposal Methods Employed for Hazardous Spill Residuals
Method Used No. of Incidents % of Total_
None 28 36
Water Wash 19 24
Chemical Treatment 9 11
Recovery 6 8
Landfill 2 3
Biological Treatment 1 1
Nothing Reported J_3_ 17
Total 78 100
Most of the hazardous material spills other than oil involve the
widely used chemicals of industry and agriculture such as ammonia and
sulfuric acid. A water wash is frequently used for these materials when
the spill occurs on land. No action whatsoever is usually taken for small
spills of anhydrous ammonia since tnis material quickly evaiorates to the
air- Of particular concern are the spills of highly toxic materials such
as certain pesticides. One of the most widely publicized pesticide spills
occurred when a plant in Virginia, producing Kepone, a chlorinated
hydrocarbon, allowed spills and off-standard batches of this material to
be discharged to the local sewage treatment plant and then to the James
River.(9) A considerable quantity of river sediments and soil has
become contaminated with Kepone as a result. The cleanup and disposal
problems associated with this Kepone spill are enormous. Two small spills
of pesticides occurred on highways, one involving 60 liters of a 1%
solution of a chlorinated hydrocarbon and another involving 210 liters of
an organophosphate compound. No cleanup action was taken in the former
while sand was used to sorb the latter. (The contaminated sand was
disposed in a landfill.)
A large number of spills and releases of pesticides or other
extremely toxic materials occur but are not reported. Because of the
small number actually reported, it is difficult to assess the adequacy of
the disposa": methods used. However, it is judged that landfill disposal,
frequently as surreptitious dumping, is most commonly used for these
materials and may rank only slightly ahead of illegal disposal in sewers
or watercourses.
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Disposal Problems Encountered
Review of the literature and consultation with privc~e firms reliably
dealing with hazardous materials spills indicate that the most frequent
problem encountered is locating a disposal site for the spill residual.
Following the publicity usually associated with a spill, local residents
generally do not favor the disposal of spill residuals in nearby landfills
even though the landfill may be suitable to receive this waste.
Furthermore, some states have become quite restrictive in allowing
hazardous wastes to be shipped in from other states for disposal and court
tests are expected.
Improper design, location, and operation of landfills are well-known
problems that can result in loss of confinement of the hazardous materials
disposed at these sites. The Environmental Protection Agency has proposed
regulations for disposal of hazardous wastes.(5) When promulgated and
ultimately amended as necessary, these regulations will dictate the
reporting, packaging and labeling methods that must be employed for any
waste defined as hazardous. As a result, many of the options now open for
spill residuals management will be legally closed.
Poor communication between regulatory agencies and disputes between
these agencies concerning jurisdiction over the spill incident have been
reported as frequently occurring problems by private contractors involved
in the business of cleaning up spills. The problems are viewed as
transient and remediable as areas of jurisdiction are defined and
regulations promulgated.
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SECTION 5
DESCRIPTION AND ASSESSMENT OF CONVENTIONAL DISPOSAL ALTERNATIVES
In the following sections, techniques leading to ultimate disposal of
hazardous or toxic materials are reviewed. Many of these methods are not
ultimate disposal techniques in themselves but do constitute unique and
necessary steps in an ultimate disposal process. For this reason these
processes such as low-temperature fixation and certain types of
precipitation, are included in discussions of ultimate disposal
techniques. However, steps that have very general application, such as
sedimentation and filtration, are considered as dispor.al pr2-treatment
procedures.
BIOLOGICAL TREATMENT
General Description
Biological treatment processes are those which utilize microorganisms
(mainly bacteria) to oxidize dissolved and colloidal organic matter in
wastewaters. (Anaerobic treatment is not being considered here.) The
microorganisms metabolize the organic matter in wastewater to yield energy
for synthesis, reproduction, motility, and respiration. Biological
utilization of organic compounds involves a series of enzyme-catalyzed
reactions. Simple dissolved or soluble organic compounds are readily
transported through the cell walls of microorganisms and oxidized (or
accumulated). When some microbial cells come into contact with complex
organics, extra-cellular enzymes are released by the cells to hydrolyze
such high molecular weight materials as proteins, sugars, and fats into
diffusible fractions, enabling their transport though the cell wall for
assimilation. The larger, more complex organic compounds are thus
metabolized at a much slower rate. Some complex organic compounds are not
or cannot be degraded by biological oxidation; these are called
"refractory" organic compounds. Other compounds can be metabolized by the
microorganisms at low concentrations but are toxic at high
concentrations. In the case of toxic substances, a period of acclimation
is frequently necessary to allow the microorganisms to "adjust" to these
materials. A different population of microorganisms (including mutants)
may develop during the acclimation period and subsequently provide more
effective treatment.
The relationships between metabolism, energy, and synthesis are
important in understanding biological treatment systems. The primary
product.of metabolism is energy, and the chief use of this energy (usually
in the form of "high energy" organic phosphates) is for synthesis. Energy
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release and synthesis are coupled biochemical processes, where the maximum
rate of synthesis occurs simultaneously with the maximum rate of energy
yield (maximum rate of metabolism). This process may be simplistically
represented by the following reaction:
soluule organics + 02 + microorganisms—» C02 + H20 + energy + microorganisms,
(Nitrogen and phosphorus compounos, trace elements, and other
"requirements" must be available.) The primary purpose of most biological
treatment processes is to convert soluble or colloidal organic substrates
to C02, H20, and settleable matter (usually biomass or sludge) that can
be removed by sedimentation, in the case of hazardous or toxic substances,
note that complete removal may not be achieved and that the metabolites
from the process may also be toxic in themselves. Dilution (or other
pre-treatment) may be necessary if biochemical conversion is to achieve the
desired reductions in the quantity of the pollutants being biodegraded.
(For optimized performance, the microorganisms (bacteria, fungi, algae,
protozoa) almost unilaterally set "workplace11 conditions: oxygen,
pollutant, food, salinity, nutrient, illumination, and population levels,
pH, temperature, etc.)
Efficient and successful biological oxidation of organic wastes
requires a minimal quantity of nitrogen and phosphorus for the synthesis of
new cells. In addition, trace or larger quantities of several other
elements such as sodium, potassium, calcium, magnesium, iron, manganese,
vanadium, copper, nickel, etc. are required. The "trace" elements are
usually present in natural waters in sufficient quantities to satisfy
iaquirements for microbial metabolism. However, nitrogen and phospnorus
levels are sometimes deficient in wastewater substrates and cause
reductions in removal efficiencies of biological treatment systems. In
such cases, nutrients must be added to supplement those in the wastewater
substrate. Nitrogen should be added as a supplement in the form of
arnmoniacal nitrogen, because nitrite and nitrate nitrogen are not so
readily available for microbial usage. Several soluble phosphorus salts
that are readily assimilated by microorganisms are available. Generally, a
BOD:N:P ratio of 100:5:1 ib thought to be the optimum ratio of nutritional
requirements for microorganisms utilized in biological waste treatment.
(BOD or biochemical oxygen demand is the term applied to signify the
strength of biodegradable organics in wastewater and is defined generally
as the amount of oxygen required by microorganisms to biologically oxidize
a given quantity of organics. The more concentrated the organic waste
material, the higher the BOD. Some workers prefer measureFifhl of COD (car-
bon oxygen demand) or TOC (total organic carbon).
Biologically degradable organics in wastewater can be dissolved in
solution or be in solid form. Only dissolved (or soluble) organics can be
metabolized within microbial cells. In wastewaters, the undissolved forms
of biodegradable organics may be colloidal or suspended solids. These may
be hydrolyzed to soluble forms by exoenzymes released from within microbial
cells. (These remarks apply chiefly to bacterial action.)
5-2
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There are a number of approaches that utilize biological processes.
These include activated sludge ^nits, biological filter systems, aerated
lagoons, oxidation ponds, land application systems and anaerobic
fermentation reactors. Selection of a particular system is generally based
on wastewater cnaracteristics and volume, desired levels of pollutant
removal, and location. Biological systems generally achieve 50 to 90% BOD
removal althougn higher removal can be attained under optimum conditions.
Activated sludge units, biological filters, and stabilization ponds are the
most widely used oiological treatment processes. These processes along
with land application—a widely usea industrial process—are discussed
below.
Activated Sludge Process
The activated sludge process involves the production of a suspended
mass of microorganisms in a reactor to biologically convert soluble organic
conpuunds in wastewater to carbon dioxide, water, additional microorganisms,
and energy. In operation of the activated sludge process, wastewater
containing soluoie or finely suspended organic compounds is fed to the
aerobic reactor (aeration tank) which furnishes 1) air required by
microorganism; to oiochemically oxidize the waste organics, and 2) mixing
to insure intimate contact of microorganisms with the organic waste (see
Figure 1). The aerobic reactor contents are referred to as mixed liquor
suspendeo solids fMLSS). In ti.e vigorously mixed aerobic reactor, the
organic wastes ire metabolized to provide energy and growth factors for the
production of more microorganisms with the release of carbon dioxide ana
riater as metabolic end products. The organic waste compounds may thus be
degraded to innocuous end products (including inorganic salts) and also
utilized to form more microorganisms. The MiSS flows from the aeration
tank to a sedimentation tank, wiiich provides quiescent settling to allow
separation of the biological solids from the treated wastewater. The
treated and clarified water is collected and discharged as process
effluent. Most of the settled biological solids are recycled (as return
activated sludge) to the aerobic reactor to provide an activated mass of
microorganisms for continuous treatment of incoming wastewater. Some of
the settled biological solids are wasted to maintain a proper balance in
the population of microorganisms in the MLSS of the aerooic reactor.
The activatea sludge process is very flexible arid can be utilized for
the treatment of almost any type of biodegradable waste. The original
process configuration is called the conventional activated sludge process,
and has been modified in numerous ways. In the original conventional (or
plug flow) activated sludge process, wastewater and return activated sludge
enter one end of a long narrow aeration tank and are mixed in a longi-
tudinal direction as flow occurs along the length of the tank. The long,
rectangular aerotion tanks are generally designed so that the total tank
length is 5 to £u times the wiotn. Air is supplied by bubble type
diffusers that csuse a spiral ana helical flow of the mixed liquor as it
flows to the exit end of the tank. The spiralling flow along the length of
the tank is a uniform, straight-line flow pattern, hence the name
"nlugflow." Conventional and other activated sludge process variations are
discussed in References 10-15.
5-3
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in
i
SEDIMENTATION
TANK
AIR
I
RAW
•MM
INFLUENT
WASTE SLUDGE •<-
V//////////////////A AIR SUPPL*
4
n
s I
! !
i i j_ j.
AIR alFFUSERS-^"^
AERATION TANK j
RETURN ACTIVATED SLUDGE
EFFLUENT
FINAL
SEDIMENTATION
TANK
FIGURE,!. Activated Sludge Process
-------
A process tnat differs significantly from plug flow is the complete
mix activated sludge system which has become one of the more popular
designs in recent years because of its greater ability to withstand shock
loads and the introduction of new, chemically different toxic substances.
In the complete mix system, influent waste water is uniformly m-'xed
throughout the entire aeration basin as rapidly as possible. The mixing
tends to produce a uniform organic load through the entire contents of the
aeration basin. Since the influent, wastes are mixed throughout the
aeration basin, the entire basin volume acts to buffer hydraulic surges
and organic shock loads. For example, it has been shown that 100 mg/1 of
phenol io toxic to tne conventional activated sludge process, whereas a
loading of 2000 to 3000 mg/1 pnenol was not toxic in the complete mix
system.(16) This feature enables the establishment of near-equilibrium
conditions for stable operation.
Trickling Filter
The trickling filter process Consists of a fixed bed of coarse, rough
material jver which wastewater is intermittently or continuously
distributed in a uniforn manner by a flow distributor (see Figure 2).
Microorganisms grow on the surface of the filter 'media forming a
biological or zoogleel slime layer. As wastewater flows downward through
the filter, the fluid passes over the layer of microorganisms. Dissolved
organic material and nutrients in the wastewater are taken up by the
zooqleal film layer for utilization by the microbial population. Oxidized
end products are released to the liguid and collected in the underdrain
system for discharge via the effluent channel. Aerobic conditions are
maintained by natural draft, wind forces, temperature differences (filter
vs. ambient), and entrainment of air by the wastewater as this fluid
passes through the filter bed. A trickling filter will operate properly
so long as the void spaces are not clogged by solids or by excessive
growtn of the joogleal film layer. The zoogleal film layer g^ows and
gradually increases in thickness to the point that the hydraulic shear
force from the downward flow of wastewater causes portions of the film
layer to slough off the filter media. The slougned filter film is
separated as sludge in secondary clarification units.
The trickling filter process has some advantage in reliability over
the activated sludge process. The reservoir of captive microorganisms
that are readily adjustable to shock loadings is the basis of its
dependability. "The trickling filter achieves consistent BOD removals in
the face of fluctuating hydraulic and organic demands. The recent
introduction of plastic media (instead of minerals, Elag, etc.) has
resulted in shortened detention time requirements through the filter,
though BOO removal is still limited to a maximum of about 85%. A second
innovation recently introduced is the recirculation of biofloc from the
system back through the filter, achieving high EOD/COD removal efficiency
(COD = carbon oxygen demand). The recirculated trickling filter is
similar to an activated sludge process, and attains the same high (90%)
BCD removal. Additional information concerning the design and operation
of trickling filters is available in References 12, 17. 18 and 19.
5-5
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FIGURE 2. Trick11 ng Filtar'Uiagram
5.6
15
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Waste Treatmert Lagoons
Wastewaters may be effectively stabilized by the natural biological
processes that occur in relatively shallow ponds. Stabilization is"
attained by photosynthesis by algae and/or oxidation by bacteria. Waste
stabilization ponds (or lagoons, as they are sometimes called) are very
popular with small communities because of their low construction and
operating costs, which offer a significant financial advantage over other
recognized treatment methods.
Waste stabilization ponds are generally classified according to the
nature of the biological activity and environment within the pond. Thus
stabilization ponds are classified as aerobic, aerobic-anaerobic (or
faculative), and anaerobic. A waste stabilization pond system may include
a single pond or a number of ponds in series or parallel. Also, different
classifications of ponds may be utilized in series, i.e., aerobic followed
by an anaerobic or vice versa. This switch between aerobic and anaerobic
conditions is usually done to effect greater treatment efficiencies than
can be achieved via a single pond type.
Aerobic ponds are additionally separated into two categories based on
whether natural or artificial methods are utilized to supply oxygen to the
bacteria in the pond. In natural aeration, oxygen is supplied by surface
aeration and by algal photosynthesis: such ponds are generally termed
"oxidation ponds." Mechanical aeration units can be used to artificially
supply oxygen to the bacteria. The artificial (mechanical) aeration
process is essentially the same as the activated sludge process, but
occurs without recycle of microorganisms. Mechanically aerated ponas are
generally termed "aerated lagoons."
Oxidation ponds utilize algae and bacteria in a symbiotic
relationship to stabilize waste organics. The oxygen released by the
algae through the process of photosynthesis is utilized by bacteria for
the aerobic degradation of organic matter. The nutrients and the carbon
dioxide released via bacterial respiration are, in turn, used by the
algae. During the daylight hours, increased algal photosynthetic activity
occurs and oxygen concentrations may reach supersaturation levels.
Generally, solids will accumulate and settle in an oxidation pond because
of the lack of nixing. The accumulated settled solids form an anaerobic
sludge layer on the bottom, and the pond becomes an aerobic-anaerobic
(faculative) pond. Oxidation ponds generally are relatively shallow (3 to
5 ft deep). (20) (1 ft = 0.3m)
Aerated lagoons are an outgrowth of the development of the completely
mixed activated sludge process. Surface mechanical aerators are applied
to overloaded oxidation ponds. Aerated lagoons are generally constructed
at depths of 8 to 15 ft.(20,21) Generally, no consideration is given to
algie for supplying dissolved oxygen because the pond surface is turbulent
and the growth of algae is inhibited.
Aerobic-anaerobic (facultative) ponds were historically known as
stabilization ponds. The symbiotic algae-bacteria relationship is
5-7
15
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utilised to its fullest in these pondi. The ponds are generally 3 to 8 ft
in depth. The solids settle to the bottom and eventually decompose
anaerobically. The decomposition results in the interchange of anaerobic
decomposition byproducts with aerobic oxidation byproducts between the
upper and lower portions of the pond.
Anaerobic ponds were the inevitable result of the widespread use of
"stabilization" ponds (faculative) where the organic loading rates became
excessive and caused anaerobic conditions tnrougnout the pond. The
symbiotic stabilization relationship failed but was replaced by an
anaerobic stabilization process where waste organics are stabilized by
anaerobic, methane-forming bacteria similar to those which ocur in
anaerobic digesters.
Land Application
Land application as a treatment and disposal method utilizes the
interactions between plants and the soil surface to effectively stabilize
many different types of wastes. The combinplion of plants ana soil can
serve as a natural biological filter(22,23) since most top soils already
contain the microorganisms needed for biochemical decomposition of organic
matter. In addition, physical and chemical processes can occur within the
soil to neutralize either strong acids or bases, remove inorganic
constituents and filter out suspended solids. Passage of the Federal
Water Pollution Act PL 92-500 has focused attention on land application as
an alternative for effective treatment and disposal of wastewaters and
sludges to comply with zero discharge requirements slated for 1985,
General criteria for judging the suitability of land disposal for a
particular waste follow:(24)
1. The organic material must be biologically degradable at reasonable
rates.
2. Th2 waste must not contain materials in concentrations toxic to soil
microorganisms. Since some toxic materials may accumulate through
adsorption or ion excnsnge and approach toxic levels after prolonged
operation, there must be reasonable assurance that this effect can
either be prevented or mitigated.
3. The organic waste must not contain substances that will adversely
affect the quality of the underlying groundwater. In many instances,
decisions relative to this aspect of land disposal systems are
difficult to make because of the uncertain nature of available
estimating techniques. Nitrate-or nitrate-forming compounds are
often a limiting factor (nitrification) in this regard.
4. The waste must not contain substances that cause deleterious changes
to the soil structure, especially its infiltration, percolation, and
aeration characteristics. An imbalance of sodium is the most common
problem of this kind.
Land application is suitable for disposal of many different hazardous
materials including oil residues.(25)
5-fi
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Application of liquid wastes to land is generally accomplished by
irrigation methods. Solids may be applied through the use of mechanical
spreading devices installed on the truck or carrier used to haul tne waste
to the disposal site.
Assessment of Biological Methods
Biological degradation is probably tne most common method of ultimate
disposal for organic and organic-contaminated hazardous materials spill
residuals. The use of this method is perhaps not intentional in most
cases but it occurs, nevertheless, as a natural phenomena either in the
soil or the water that receives biodegradable organic hazardous material
spill residuals. Over half of the hazardous materials listed in
Appendix A are capable of biodegradation although, in many instances,
dilution or some form of pretreatment (e.g., neutralization) is needed to
allow the process to occur.
Intentional use of biological degradation processes, as in a
municipal sewage treatment pl^nt, is a viable option for disposal of
biodegradable hazardous materials spill residuals; however, considerable
care must be exercised to avoid plant upsets because of excessive loading
of toxic materials or of large inflow surges of biodegradable matter.
Permission to use a local sewage treatment plant for disposal of toxic
material will probably be difficult to obtain unless the amount of
material is small and toxicity is not a problem. Contracting the services
of a private waste disposal firm that operates a biological treatment
facility is a recommended option in those instances where discharge to a
municipal sewage treatment plant is not possible. The cost of disposal by
biological degradation ranges from essentially nothing (e.g., spill is
simply allowed to drain to soil) to about $4 per m3 (1.6^/gal) of
wastewater containing 200 mg/1 BOD. This upper level of costs is based on
a prefabricated 10,000 gpd (40 m3/d) extended aeration activated sludge
unit(26), with capital amortized at 10% over 5 years. This cost is
equivalent to about $20 per kg of BOO disposed. Considerably less costly
biodegradation operations are possible in lagoons or at land application
sites where the cost of land is low. Land application is particularly
attractive for waste oil disposal.(25)
Biodegradation of hazardous organic substances may not be practical
in many instances because of very slow conversion rates or of toxicity
problems. Acclimation of the biological culture to a particular organic
substance may be necessary to achieve acceptable biodegradation rates.
Certain classes of organic compounds are more resistent to biodegradation
than others. For example, hydrocarbons—particularly, cyclic structures —
and ethers are more resistant than alcohols, aldehydes, ketones, and
acids. Biological oxidation data for many organic chemicals was reported
by Heukelekian and Rand.(27) The relationship of biodegradability to
chemical structure has been discussed by Ludzak ar;d Ettinger.(28)
Amenability to biological treatment is indicated for most of the organic
compounds listed in Appendix A.
The selection of biodegradation for disposal will also be affected by
the substrate materials with which spill residuals are associated.
5-9
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Aqueous organic wastes are most readily treated biochemically. The
presence of large quantities of solids, combustible or noncombustible, may
cause difficulties with a given biochemical process. High solid loadings
may interfere with settling processes or inhibit uptake and metabolism by
active cell masses. In such cases, land application or a composting
process could be preferable.
INCINERATION
General Description
As the environmental problems associated with many of the relatively
cheap disposal options for hazardous wastes become increasingly evident,
incineration has become the alternative of choice for destroying many
organic hazardous wastes. The number and types of industrial waste
incinerators are continually increasing.
Incineration is essentially a controlled oxidation process that is
used to convert organic waste to CO?, HzO, and ash. Compounds in the
waste containing sulfur, nitrogen, phosphorous, and halogens may also be
oxidized to produce sulfur, nitrogen, and phosphorus oxides and hydrogen
halides. The toxic or hazardous property of organic waste usually arises
from the; structure of the organic molecule- as opposed to the properties of
the elements that it contains. Therefore, destruction of the molecular
structure to produce CC>2, HpO, and inorganic oxides or halides
eliminates the toxic or hazardous property. The existence of elements
otner than carbon, hydrogen, and oxygen (e.g., heavy metals) in the waste
may result in the appearance of toxic materials in the ash or off-gas.
The principal advantages to the use of incineration include:(29)
1. The basic process technology is available and reasonably well-
developed.
2. The process is broadly applicable to most organic wastes and can
handle large volumes.
3. Large land areas are not required.
4. The process is relatively rapid and not subject to upset due to toxic
materials.
5. Operation is better understood than that for biological processes and
therefore more easily optimized.
There are some generally applicable disadvantages:(29)
1. The equipment tends to be more costly and more complicated to operate
than many other alternatives. Incineration facilities may not be
conveniently located for periodic users.
2. The asn that usually results may or may not be toxic depending on the
material incinerated so that incineration may not always be a means
of ultimate disposal. In any case, the ash must be disposed.
3. Air pollution control equipment is required for treatment of the
gaseous combustion products and of particulates.
5-10
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Types of Incinerators
There are many types of incinerators that may prove adequate for
destruction of most hazardous wastes. These will be discussed briefly in
the following paragraphs. A more detailed discussion of the most
applicable incineration methods is included in Appendix B.
Most incinerators currently used to burn hazardous materials are
installed at industrial plant sites where the wastes are generated or at
privately owned, central disposal facilities. The use of municipal waste
incinerators to handle some hazardous wastes is being considered. Until
recently, all hazardous waste incinerators have been land-based; however,
hazardous wastes are currently being destroyed on specially equipped
incineration snips in the Nortn Sea and in tne Gulf of Mexico and a mobile
incineration system is under construction by EPA.
The various types of incinerators include open pit incinerators,
multiple chamber incinerators, multiple hearth incinerators, rotary kiln
incinerators, fluidized bed incinerators, liquid combustors, catalytic
combustors, gas combustors, flares and molten salt incinerators. To the
above may be added secondary abatement equipment, such as an afterburner
device. Afterburners are themselves incinerators for completing the
combustion of gases from the primary incinerators.
Open pit incineration has very limited application to the ultimate
disposal of wastes and will not be considered further as a technique
because of uncontrolled gaseous effluents. Note, however, that this
technique has often been used for disposal of oil soill residues in remote
locations and of certain waste explosives.
Multiple chamber incinerators are used for the disposal of solid
wastes and are of two general types. The retort multiple chamber
incinerator design is distinguished by the arrangement of chambers chat
forces the combustion gases to flow through 90 turns in both lateral and
vertical directions. The in-line multiple chamber incinerator allows flew
of the comDustion gases straight through the incinerator with 90 turns
only in the vertical direction. A capacity of from 50 to 750 Ib/hr is the
most efficient operating size for the retort incinerator. The upper limit
for the use of the in-line incinerator has not been determined. When the
moisture content of the combustible waste exceeds 10% by weight,
supplementary gas burners are usually required. Multiple chamber units
can be operated by one or two nen and represent proven technology. Some
of the wastes currently disposed of in multiple chambe^ units include
general refuse, garbage, wood, paper, rubber, phenolic resins, wire
coatings, acrylic resins, and polyvinyl chloride. The inability of the
multiple chamber incinerator to handle gases, sludges, tars, and liquids
limits its application in ultimate waste disposal operations. Multiple
hearth incinerators have been utilized to dispose of sludges, tars,
solids, gases, and liquid combustible v;astes. This type of incinerator-
was originally designed to incinerate sewage sludges with low secondary
fuel requirements, thus lowering operating costs when high water-content
sludges were processed. The sludge or feed material parameters that control
5-11
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combustion are moisture content, volatiles content, inert content, and
calorific value. The multiple hearth incinerator represents proven
technology and is generally applicable to the disposal of combustible
wastes. A diagram of a multiple hearth incinerator is presented in
Figure 3.
The rotary kiln incinerator consists of a drum mounted at a slight
angle from the horizontal on rollers to allow rotation in service (see
Figure 4). The combustion chamber is lined with refractory materials to
prevent damage to the steel shell. The rotary action during combustion
leads to excellent mixing of solid or liquid burning waste and oxygen.
Gases are normally not burned in a rotary kiln because the rotary action
is not required for good mixing of oxygen and burning material during
gaseous waste combustion. Tt.e lenyth-to-diameter ratios of rotary
incinerators vary from two to ten, depending upon the residence time ne^ds
of the combustible materials. Rotational speeds vary from 0.5 to
2.5 rpm. Combustion temperatures range from 870° to 1650°C, with solid;
residence time variations from minutes to hours. Efficient air seals and
negative operating pressures assure that no leakage of toxic or noxious
waste gases occurs. Sometimes a heat exchanger is used to preheat
combustion air with realization of a significant increase in incineration
capacity. The rotary kiln incinerator is generdlly applicable to the
ultimate disposal of any form cf combustible waste including explosives,
chemical warfare agents, gases, sludges, and viscous liquids (tars) and
represents proven technology.
Fluidized bed incineration is a relatively new technique for the
ultimate disposal of solid, liquid or gaseous combustible wastes (see
Figure 5). The bed is contained in a steel cylinder in which the
fluidizing air enters from the bottom through a distributor plate,
fluidizing a Sand or inert bed above the plate. The waste material is
injected into the bed above the distributor plate and combustion products
leave at the top of the column. The sand bed acts as a heat sink,
transferring heat to the combustible waste, which rapidly reaches ignition
temperature and returns heat to tne bed. The larger solid wastes remain
suspended in the bed until combustion is complete. Ash fines are carried
off in the gaseous combustion products to a scrubber or other processor
before atmospheric discharge. Operating temperatures of from 760 to
870°C are reached initially with the aid of an auxiliary heater. Bed
depths vary from 15 in. to several ft (1 m = 39.37 in.), depending on the
desired waste residence time and pressure drop across the system. Gas
velocities are usually from 5 to 7 ft/sec, with maximum velocity
constrained by the size of the bed particles. The present limit in
fluidized bed incinerator diameters is 15 m (50 ft). Large diameter
solic's must be shredded, pulverized or otherwise reduced in size, before
addition to the bed to permit injection and even combustion.
The fluidized bed incinerator is generally suited to the ultimate
disposal of a wide range of combustible materials. Gas temperatures are
relatively low, minimizing the formation of nitric oxide, and excess air
requirements as low as 5% reduce the size and cost of gas treatment
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WASTE AIR TO
ATMOSPHERE
CLEAN GASES TO
ATMOSPHERE
VACUUM
FILTERS
SLUDGES
FILTRATE
GREASE AND TARS
FUEL
INDUCED
DRAFT FAN
SCRUBBERS
WATER
ASH TO
SLOWER DISPOSAL
ASH SLURRY TO FILTRATION AND
ASH DISPOSAL
FIGURE 3. Multiple Hearth Incinerator
5-13
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TAR PUMPING
FACILITY
PACK STORAGE AND
^FEEDING FACILITY
\
WATER SPRAYS
A
•J V
SCRAP METAL
FLY ASH
RESIDUE
FIGURE 4. Rotary Kiln Incinerator
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FLUE GAS
MAKEUP SAND
V
ACCESS DOCR-
AUXILIARY
BURNER (OIL CR GAS)
~~f_- - ,5AND BED--
i i
\ /
I
WASTE INJECTION
FLUIDIZiNG AiR
ASH REMOVAL
FIGURE 5. Fluidized Bed Incinerator
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facilities. In Addition, there are no moving parts in the region of
highest combustion temperatures which should result ir, prolonged equioment
life and ease of maintenance. The technology was first used commercially
in the United States in 1962, so that it is a relatively new technology.
Liquid waste incinerators are widely used in industry (see diagram in
Figure 6). When the heating value of a liquid waste is sufficiently hign
to support combustion, the material may be oxidized directly in a liquid
waste combustor. Usually a specially designed burner is required. When
the heating value of trie waste is low, the waste is atomized with air or
steam and injected into the flame of an auxiliary fuel-fired burner. The
entering 1-quia is finely atomized to droplets less than 50 m in diameter
in either two-phase nozzles or a pressure atomizer. Two-phase nozzles may
be used to mix tne air or steam and the fine oroplets of liquid before
entrance i ito the combustion chamber. When the liquid being burned is too
viscous to be atomized in the nozzle, in-line heaters or addition of a
miscible, lower viscosity liquid may be required to reduce viscosity.
Liquid cormustors require more turbulence and time for combustion to be
completed chart do gaseous combustors due to inherent liquid-air mixing
problems. Care must be taken that undesirable reactions such as
polymerization or nitration do not occur during heating of the liquid
prior to atomization. Opera-,ng temperatures for liquid waste
incinerators vary from 650 to 1650 C, depending on the feed autoignition
temperature. Residence times vary from 0.5 to 1 sec. Liquid waste
incineration is now used for the ultimate disposal of many industrial
wastes including lubricating oils, polyester paint, solvents, polymers,
resins, dyes, inks, latex paint, PVC paint, phenols, animal and vegetable
oils, potato starch, various sludges, and chlorinated pesticide wastes.
Tar incinerators are a type of liquid waste combustor specifically
designed for burning tars, contaminated solvents and sludges. Depending
on the products of combustion of the waste material, the design may or may
riot include a secondary combustion zone. Tar combustors have been
constructed to operate at specific temperatures from 98QOC to 1930°C.
At the highest temperatures, acid gases and fire brick corrosion nay
result. M wide variety of highly viscous tars and sludges can be handled
by tar burner nozzles, but there are limitations that, when exceeded, will
lead to the clogging of nozzles. Wastes exceeding these limitations
(e.g., maximum allowable viscosity) are treated as solid wastes.
Catalytic incinerators are used for ultimate disposal of combustible
wastes in low concentrations in a gaseous state. Catalytic oxidation is a
more common name for the process used for the incineration of solvents and
odiferous vapors from chemical and food processing. The effectiveness of
catalytic materials is a function of reaction temperature, waste
concentration, available oxygen, chemical composition, and geometric
design of each catalyst unit. Poisons, suppressants, and fouling agents
inhibit catalyst effectiveness. Vapors that contain metals such as
mercury, zinc, lead, or their compounds generally reduce catalyst
effectiveness ("poisoning"). A catalytic incinerator consists of a
housing containing a preheater, when required, and a catalyst bed
supported in such a manner as to expose a large surface area to the
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25
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f-LIQUlD WASTE STREAM
-STEAM
NATURAL
GAS —
PHASE
FROM THE
FIGURE 6. Flow Diagram of a Liquid Waste Incinerator
5-17
26
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incoming gases. Gas, velocities of about 6 m/sec (20 ft/sec) are commonly
used.
The maintenance costs for catalytic incinerators tend to be high
because of a gradual loss of catalyst activity through fouling or poisoning
of the catalytic surface. Cleaning, regeneration, or replacement are often
required.
Because tne waste must have a low concentration and be in the gaseous
or vapor state, catalytic incineration is usually conducted on the site cf
waste generation for odor and for toxic fume control in manufacturing
processes using oils, asphalt, nitric acid, resins, paint, and coatings or
involving roasting, rendering, and smoking. All of the hydrocarbons along
with H2$ and C$2, can be readily oxidized during catalytic incineration.
Gas combustors (direct-flame thermal incinerators) are used to dispose
of combustible gaseous wastes that have a concentration usually less than
25% of the lower flammability limit. The gases are destroyed by a flame at
temperatures of 480° to 815° C. A contaminated air stream containing
the gaseous waste is injected into the burner throat along witn fuel to
create a flame. Combustion takes place in the combustion chamoer with the
effluent gases passing to a stack. Direct-name incineration systems have
been operated continuously at 90 to 99% efficiencies and are readily
adaptable r thermostatic control. Residence times of from 0.3 to 0.5 sec
are commci. ..long with gas flows of 4.6 to 7.7 m/sec. Direct flame
incinerator applications work well in the resin industry, phthalic and
maleic anhydride manufacture, food processing, grain drying, paint and
varnish cookino, and carbon baking ovens.
Flares are basically pipes that discharge combustible gases to the
atmosphere with a flame device and pilot light on the end of the pipe to
ignite the gases. Oxygen for combustion is supplied from the surrounding
atmosphere to promote burning. Steam is sometimes injected into the high
volume gaseous stream to promote mixing. Flares are adversely affected by
strong winds, often venting unburned hydrocarbons to the surrounding
atmosphere or smoking due to incomplete oxidation of carbon particles.
Other health hazards that can be found in the smoke include sulfur dioxide,
when H2$ is present in the qas feed, and acidic effluents from
halogenated hydrocarbons. Elevated flares are used to dispose of tank and
reaction tower effluents while ground flares are used for the same purpose
on an open ground space. Flares are generally useful for the ultimate
disposal of large volumes of combustible gases5 but have the problem of
producing uncontrolled effluent gases and combustion products. For this
rejson, other types of incineration involving better effluent control are
suggested for gases that can form noxious or toxic combustion products.
A special case of incineration technology, and a relatively new
one,(32,33) is the ultimate disposal of organochlorine wastes at sea by
incineration. German firms have constructed three ships especially
outfitted for combustion operations. The Steel Plate and Construction
Company situated in the Ruhr Valley outfitted the Matthais I in 1968 and
the Matthias II in 1970. Burning operations have been carried out
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routinely in the North Sea area. In 1972, Ocean Combustion Services of
Bremen outfitted the ship Vulcanus as an incineration vessel that could
accommodate 4200 metric tons of waste. EPA tests of the comoustion of
organic chlorides containing 60 to 70% chlorine were concluded in 1974. A
permit was subsequently issued, based on the favorable test results, and
commercial burning operations began in the Gulf cf Mexico. The feed waste
included 1,2,3-trichloropropane, 1,1,2-trichloroethane, 1,2-dichloroethane,
allyl chloride, dichloropropenes, dichlorohydrins, and dichlorobutanes.
The incinerators employed were vertical liquid waste combustors about
5.2 m in diameter. In operation, fuel oil was used to preheat the
combustion chamber to 1480 C. Then 20 to 25 tonnes/hr of the
3300 kg-cal/kg, high chlorine waste was fed to the combustion chamber
whose temperature was adjusted to 1370 C. Excess air varied from 90 to
160%. The stack gases were emitted directly at about 1090 C and contained
from 25 to 75 ppm CO, 5.2-6.2% HC1, and 200 ppm Cl or less. More than
99.9% of the toxic wastes were oxidized to relatively innocuous gaseous
forms. The residence time in the incinerator varied from 0.5 to 1.0 sec.
There are land-based incinerators that can easily duplicate these results,
but emission controls are much more stringent for land-based operations.
The ocean burring permit issued in the above case was for specific
organocnloride wastes. Other types of wastes require testing before ocean
burning car, be evaluated as an ultimate disposal method.
Pyrolysis
Pyrolysis is a special incineration technique based on reacting or
burning refuse solids wHh insufficient oxygen for complete combustion.
Pyrolysis temperatures range from 500 to 800 C. Products include CO,
C°2> H20, H?, N2, CH4, small quantities of other light
hydrocarbons and char. The heating value of the resulting gas is usually
between 380-3500 kg-cal/m3 depending on whether air or oxygen is used.
The gas is typically used as a fuel gas to replace natural gas. Pyrolysis
units can be used for hazardous waste disposal; however, there are
relatively few units in operation today and the secondary treatment
faclities are typically designed for specific wastes. As a result,
pyrolysis is not considered as a significantly important technique for
hazardous waste disposal at this time.
Hazardous Waste Incineration
Incineration is most applicable to organic materials; however,
certain hazardous inorganics can be rendered harmless by oxidation. A
list of hazardous waste stream constituents for which incineration is
considered an acceptable waste treatment alternative is contained in a
report entitled Recommended Methods of Reduction, Neutralization,
Recovery, and Disposal of "Hazardous Wastes by the TRW Systems, Inc., (35)
"tor the Environmental Protection Agency.Reference to this source will
provide an indica ion cf whether a material in question may be incinerated
and, in many cases, operating procedures, parameters, and problems will be
outlined.
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Generally, hazardous wastes that can be disposed of by incineration
can be categorized in five groups, as below. The first three types of
wastes may be in either solid or liquid form while the last two are
self-explanatory.
1. Group I. Includes organic substances that contain only carbon,
hydrogen with or without oxygen and/or nitrogen and oxygen (sometimes
sulfur). The combustion products are clean and can be discharged to
the atmosphere with minimal off-gas treatment.
2. Group II. Organic substances containing halogens, sulfur, phosphorus,
and silicon. Chemicals such as carbon tetrachloride, vinyl chloride,
ethyl bromide, PCB, chlorinated pesticides, and other halogenated
materials appear in this group. Heating value of halogenated wastes
depends on the halogen content and these wastes may or may not need
an auxiliary fuel. The products of combustion will contain acids or
oxides, which require air pollution control devices.
3. Organic/Metallic Wastes. Wastes that have metals or metallic
compounds mixed with organic wastes, as well as organic wastes
continuing chemically bonded metals (organometallic compounds). When
these wastes are oxidized, the combustion products will contain
salts, which require that special attention be given to refractory
selection, oxidation temperature, and residence time. Auxiliary fuel
is often required for complete oxidation of these materials.
Sub-micron particulates and mists in the product gas will require
secondary gas treatment equipment.
4. Aqueous Wastes. Any or a combination of the above wastes in a
solution of greater than 60% water. Because of the low heat of
ccrrhustion, this group of wastes do not support combustion in a
burner and require an auxiliary fuel.
5. Solid Wastes. Any or a combination of the above wastes adsorbed
onto, absorbed into, or mixed with a nonhazardous solid material.
This group includes such items as contaminated adsorbents; sludge
from waste water treatment; sawdust, straw, and other absorbents used
to clean up hazardous materials spills; residual material from a
soill cleanup; whole capacitors containing PCB; and "empty" pesticide
cartons and containers.
Liquid organic wastes can usually be incinerated simply ana easily in
a liquid cornbustor providing their viscosity is low enough (750 ssu or
less) for proper atomization. A thermal vortex burner (see Figure 7) is
reported to work well in this application.(34) when proper operating
conditions are maintained, organic wastes can be completely oxidized.
Liquid halogenated wastes, when their heating value is sufficiently
great, may be oxidized in the same manner as organic wastes. Wastes with
high halogen content (60-70% chlorine by weight) require auxiliary fuel.
In this case, the waste is atomized by steam or air and injected into the
flame zone of the burner just beyond the exit of the burner combustion
chamber. Halogens and hydrogen halides will be present in the combustion
gases. Hydrogen halides can be removed by conventional wet scruboing
techniques; however, halogens are more difficult to handle. As a result,
hydrogen or methane is often added to the combustor to assure complete
conversion to halides.
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*>S*C>0:A a'-:--'-/--:
COMUfTIOMMt
FIGURE 7. Thermal Vortex Burner(34)
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Liquid organic/metallic wastes and aqueous wastes, which do not
support combustion and thus require an additional fuel, may be atomized
and injected into the flame zone of the burner. Aqueous wastes are often
preconcentrated to reduce secondary fuel costs. Materials containing
toxic heavy metals should not be incinerated unless the fate of the metal
components is known and can be satisfactorily controlled by pollution
control equipment. Some of these metals may end up not only in the ash
but in the gaseous combustion products as well.
Combustion of solid wastes and organic, halogenated, ano metallic
wastes in solid form is not so straightforward. Incineration of solid
hazardous wastes has not generally been considered an acceptable means of
disposal because most of the solid type incinerators in existence were
municipal refuse incinerators, which did not operate at conditions
appropriate for destruction of hazardous wastes and did not have suitable
air pollution equipment.
Rotary kiln incinerators specially designed for waste disposal have
been used successfully to incinerate many types of hazardous solid wastes
including explosives ana chemical warfare agents.(35) Recently PCB-
containing capacitors and nitrochlorobenzene wastes were incinerated in a
commercial-scale rotary kiln incinerator with 99.999% destruction
efficiency.(36) A rotary kiln incinerator was used to incinerate sewage
sludge contaminated with Kepone and Kepone wastes. Destruction
efficiencies of 99.999% were achieved.(37) Rotary kilns are used by
industry to dispose of refuse consisting of plastics, wood, paper, and
other combustible material inducing hazardous chemical wastes.
Generally, rotary kiln incinerators designed for waste disposal and
equipped with suitable pollution control equipment can be considered an
acceptable means for disposal of hazardous solid wastes; however, this
type of facility is not readily available in many areas. A map giving the
location of rotary kiln, liquid, and other types of hazardous waste
incinerators is presented in Figure 8 (Ref 35).
The newer sludge incinerators that utilize fluidized bed or multiple
hearth technology adapted from other industries are potential systems for
hazardous solid waste disposal. These new facilities can often be
operated at conditions acceptable for hazardous waste destruction and are
usually equipoed with suitable air pollution equipment. The large number
of these types of incinerators make them particularly attractive. Tests
were recently performed with DDT, 2,4,5,-T, and PCB to determine whether
these materials could be coincinerated with sewage sludge in a multiple
hearth incinerator.(38) in these tests, concentrations of the hazardous
waste material ranged from 2 to 5% based on dry sludge weight.
Destruction efficiencies were 99.99-% for DDT, 99.97+% for 2,4,5,-T, and
94% for PCB. The lower destruction rate for PCB may have resulted from
the configuration of the incinerator used. The sludge was fed through the
top hearth, and it is conjectured that some of the volatile PCB's were
vaporized directly into the gaseous exhaust and were discharged from the
incinerator before being oxidized.(39)
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FIGURE 8. Location of Hazardous Waste Incinerators in the Unit3d States
-------
The five types of incineration generally employed for destruction of
toxic organic water are illustrated in Table 2, which also shows the types
of feed materials that each is capable of processing.(41) Successful
application of incineration requires accurate and reliable information
about the composition and characteristics of the waste to be processed.
Specifically, for waste to be incinerated, the following are
determined initially:(42)
. heat content
. acid scrub requirement (elemental composition)
. ash content
. specific gravity.
Other evaluative or process control tests, such as burn rate, are
conducted later and are based on the initial test results.
As a general rule most organic hazardous materials can be virtually
destroyed in an oxygen-rich atmosphere at 1000°C at a dwell time of
2 sec.(29) Many are completely destroyed at lower temperature/dwell
time conditions but some (e.g., DDT, PCB's) require rrore rigorous
conditions. Proposed RCRA regulations specify a temperature of 1200°C
for 2 seconds for chlorinated aromatic hydrocarbons (5). Proposed
operating criteria for destruction of PCB's are 1200°C with a 2-second
dwell time and 3% excess oxygen.
Assessment
Incineration is a wioely applicable and reasonably viell-developed
method for hazardous waste disposal. When undertaken with proper air
pollution control equipment, incineration can be used to completely
dostroy approximately 60% of the hazardous materials listed in Appendix A
with little or no affect on the environment. This includes all
hydrocarbons, haiogenated organics, and organics containing nitrogen,
oxygen, and sulfur. (Incineration is not always classified as an ultimate
disposal method since any hazardous (heavy metal) or nonnazardous ash
resulting from incineration must be disposed of separately.)
Organometallic wastes can also be handled by incineration; however,
special consideration must be given to the selection of refractory liners
and to air pollution control equipment design. Note that the resulting
ash may contain hazardous metallic compounds,
The cost of incineration varies with the type of incinerator and the
waste material. Typically, costs range from $9 to $31/tcnne of waste for
solid incinerators (fluid bed, rotary kiln, and multiple hearth units) and
$0.26 to $26/m3 for liquid combustors.(35) These are total capital
and operating costs for the year 1973. Capital costs are around 75% of
the total.(35)
These costs do give an incomplete indication of the true cost of
disposal of hazardous materials from a spill or release. The total cost
of disposal depends on the type of spill (cost of spill cleanup and
preparation for incineration) and the location of the spill
(transportation costs to the incinerator).
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TABLE 2 PROCESSING CAPABILITIES OF FIVE TYPES
OF COMMONLY USED INCINERATORS
Process
Rotary Kiln
Fluidized Bed
Multiple Hearth
Liquid Injection
Pyrolysis
Waste Form
Solid* Liquid
X X
X X
X X
X
X
Gas
X
X
X
* " Size reduction may be necessary
X Acceptable
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Most incinerators that routinely burn hazardous wastes are located at
industrial plant sites or privately owned, central disposal facilities.
The number of these facilities, while growing fast, is small. It is not
likely that one of these units would be convenient or available to handle
waste material from a spill.
There are a large number of nev/er sewage sludge incinerators using
fluid bed or multiple hearth technology with suitable air pollution
equipment that could be used for destruction of hazardous material from a
spill or release.
In general, incineration is the most effective means of destroying a
wide range of hazardous materials with the smallest impact on the
environment and is the method of choice for disposal of nonbiodegradable
and highly toxic organics. However, incineration is more costly than
other disposal methods such as biological treatment and landfilling, and
properly equipped facilities are not readily available for periodic
users. Availability is limited further since individual incinerator types
cannot necessarily handle all substrate forms. Hence selection of a unit
must be based on a number of factors:
- proximity;
- design criteria as compared to the operating parameters required for
the hazardous material involved;
- ability to handle the substrate form; and
- capacity.
NEUTRALIZATION
Description of Process
Neutralization may be defined as adjustment of the pH of a solution
to a level between 6 and 9. Neutralization to this pH range normally
renders an aqueous solution safe to discharge to receiving waters or soils
with respect to hydrogen ion concentration. There are a number of methods
available to effect the neutralization of acidic or caustic
solutions.(43,44) Lime slurries and solutions of caustic soda (NaOH) or
soda ash ('^COs) are commonly employed by industry to neutralize
excessive acidity. Excessive alkalinity is generally neutralized by the
addition of sulfuric or hydrochloric acid solutions or by sparging flue
gas(or CC>2) tnro'jgh the solutions. Control led addition of these
reagents is required, except in the cas'? of C02, to avoid adding
excessive amounts ana overshooting the desired pH range. Controlled
addition is generally a:complished in ,' tank where the treated solution
can be easily monitored for ph with the aid of a pM meter or color
indicators. A spill of acid or caustic naterial outside such a controlled
environment cannot be neutralized as easily. The recommended approach to
in situ neutralization is the use of weakly acid or weakly basic materials
for neutralization of alkaline and acidic spills, respectively.(45)
Powdered limestone (CaCO^) and baking soda (NaHCOs) are excellent
reagents for neutralizing acid spills. Both of these reagents are capable
of neutralizing acid without exceeding the pH 9 limit. Furthermore, the
cessation of C02 evolution when additional quantities of these reagents
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are added to a spill indicates completion of the neutralization reaction.
Neutralization of caustic spill residuals with CO? would be the
best approach to neutralizing excessive alkalinity from an environmental
viewpoint; however, in situ application of C02 may be difficult in most
instances. Alternate commonly available weakly acidic reagents include
acetic acid, aluminum sulfate (?.1um), sodium mono- or di-hyclrogen
phosphate, and ferrous sulfate (copperas). Acetic acid has the
disadvantage of contributing BOO to receiving waters and aluminum or
ferrous sulfate can add metal ions and excessive acidity when more than
the stoichiometric quantity is usea. Phosphates are nutrients for
biological systems and high levels may be undesirable.
Neutralization is frequently used as a pretreatment step to effect
the precipitation of a toxic ion such as Cr+3. The ultimate disposal
method used in this case may be disposal of the hydrous chromic oxide in a
secure landfill. Lime is also used in a like manner to neutralize
excessive acidHy while precipitating toxic or undesirable anions such as
fluoride, arsenate, and phosphate.
Assessment
Neutralization is considered as an ultimate disposal step only for
those acids and alkalies that can be rendered nonhazardous by this
method. Common hazardous materials included in this category are listed
below:
calcium hydroxide potassium hydroxide
calcium oxide sodium hydroxide
hydrochloric acid sulfuric acid
nitric acid
Neutralization of the acids listed above with either sodium
bicarbonate or powdered limestone will result in nonhazardous reaction
products tnat can generally be flushed away with water. The use of sodium
bicarbonate is preferred in those instances where some mixing is required
to achieve effective neutralization. Sodium bicarbonate is soluble in
water and can be distributed more rapidly throughout a solution or a
porous mixture sucn as soil contaminated with acid, nood mixing normally
occurs as a result of C02 evolution in shallow pools or layers of acid
solutions treated by broadcasting solid sodium bicarbonate or powdered
limestone over the affected areas. Limited quantities of sodium
bicarbonate in the form of baking soda are Available for small acid spills
from grocery stores at approximately 50 tf per rjound. Powdered limestone
can generally be obtained from local agricultural product outlets at cost?
under 10£ per pound. Both sodium bicarbone'.>: and powdered limestone are
quite safe to handle. Substrate form will have little impact on
neutralization processes other than direct increases in reagent
requirements. For instance, seme soils may exhibit acid or alkaline
properties, wnich would augment chemical requirements. More often,
however, soil and other substrates will have buffering properties that
could reduce reagent requirements.
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PRECIPITATION
Description of Process
Precipitation in liquid medium is the formation of an insoluble or
sparingly soluble substance that is brought about by a chemical reaction,
a change in temperature, or--in the case of a supersaturated solution—the
introduction of seed crystals. Precipitation can serve to separate a
hazardous constituent from a solution to reduce the quantity of hazardous
material to be managed. Furthermore, precipitation can also render the
hazardous material much less soluble, v.hich reduces its potential for
migration from a disposal site. Under the proper conditions, a
precipitate containing a hazardous constituent may have a solubility low
enough to no longer qualify the material as hazardous when a leach test is
applied. Precipitation of chromic hydroxide is an example of the
formation of a sparingly soluble compound from a solution of a hazardous
heavy metal ion. Precipitation of chromic hydroxide by treatment with
lime is commonly performed with waste solutions containing Cr+3:
2 Cr*3 + 3 Ca(OH)2 = 2 Cr(OH)3 + 3 Ca+2
The precipitated chromic hydroxide can be separated from the wastewater by
sedimentation and filtration. In the absence of other effects (e.g.,
soluoilizing effect of chelating agents) the solubility of chromic
hydroxide in water at pH 5 is 2 x 10~H rr,g/ , which will give a Cr+3
concentration that is orders of magnitude less than the 0.5 rig/ limit
proposed for tnis metal in a leach test at pH 5.
Treatment of heavy metal salt solutions with alkaline reagents is
commonly used to precipitate the hydroxides of these metals.<4o,47)
However, one should be aware that not ell heavy metal hydroxides will
qualify as nonhazardous with a pH-5 leach solution. Cadmiun and lead
hydroxides, for example, are sufficiently soluble to exceed the proposed
RCRA limits. Nevertheless, hydroxide precipitates of heavy rretals are
useful to minimize the mobility of these hazardous substances in a secure
landfill.
Spill residues of many of the heavy metal salts listed in Appendix A
will not qualify as hazardous waste under currently proposed RCRA
guideline^. Salts of zinc, iron, copper, cobalt, and nickel, for example,
would be exempt unless associated with acidity or alkalinity outside the
pH 3 to 12 range or with other hazardous constituents (e.g., cyanide).
However, protection of the environment from mobile species of these heavy
metal ions is needed arid precipitation treatment of spill residues in
solution will serve a useful purpose in finny instances. The precipitated
hydroxides of zinc, iron, copper, cobalt, and nickel may be disposed in a
suitable sanitary landfill depending on local conditions and regulations.
In addition to hydroxide precipitates, other heavy metal precipitates
such as carbonates and sulfides may be used to prepare sparingly soluble
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compounds of these metals. Cadmium carbonate, for example, is less
soluble than cadmium hydroxide. Some of the sulfide precipitates cf heavy
metals also exhibit very low solubility (e.g., mercuric sulfide). The use
of sulfide as a precipitating agent involves careful control to avoid an
overdose, which will in itself be toxic. Furthermore, heavy metal sulfides
are prone to oxidize in the presence cf moist air and to release the heavy
metal in dilute sulfuric acid solution.
Precipitation may also be used as a scavenging process for removing
dilute hazardous metal ions from solution. Ferric hydroxide scavenging of
low concentrations of arsenic is an example.(48) Low concentrations of
other heavy metals in solution can frequently be "carried down" on a dense
floe of ferric or aluminum hydroxide. The sludges formed by scavenging
may or may not qualify as hazardous waste depending on the amount and
solubility of the hazardous metal scavenged.
Assessment
Precipitation of metal ions designated as hazardous under proposed
RCRA guidelines (i.e., As, Ba, Cd, Cr, Pb, Hg, Se and Ag) will probably
serve as a pretreatment step only and final disposition of the sludges
formed will te in a secure landfill. Under optimum conditions, however,
the soluuility of these metals can be reduced by precipitation to the
level where tne precipitate would not be designated as hazardous. In this
case it would not be necessary to rely on a secure landfill to prevent
dispersion to the environment.
Common chemical reagents that can be used to effect hydroxide
precipitation of heavy metals include lime, soda ash, sodium bicarbonate,
powdered limestone, ana sodium hydroxide. As in the case of
neutralization, in situ precipitation would best be accomplished with
powdered limestone or sodium bicarbonate since these reagents are least
likely to cause environmental damage if used in excess of the amount
needed to effect environmentally acceptable precipitation of the metal
ion. If possible, containment of spills of highly toxic metal salts
should be attempted in order to facilitate recovery of the sludge formed
by precipitation. Transfer of solutions corita'ming spill residues to
treatment vessels, either makeshift in the field(43) or at a treatment
facility, provides a better means of recovering the sludge than—for
example—in sHu treatment of an impounded stream.
Precipitation of heavy metals is likely to occur in the case of
spills on soil, especially alkaline soil. The rei'tralizing quality of
soil will cause the precipitation of heavy metal hydroxides or hydrous
metal oxides. In the case of low toxicity metals such as iron and
aluminum, this natural action will serve as a useful approach in many
instances. Precipitation in the soil may be enhanced by a water wash to
disperse the rretal salts or by treatment of the affected area with a
suitable alkaline reagent or by a combination of both.
It is anticipated that precipitation will be widely used as a method
to dispose of certain hazardous material spill residuals or as a
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pretreatment step to prepare a sparingly soluble compound of a hazardous
substance for disposal in a secure landfill. The reagents and equipment
for 3 precipitation process are readily available in most locations and
the process is relatively simple to carry out and monitor. Precipitation
is limited to a small fraction of the materials listed in Appendix A;
however, some ot these such as iron and aluminum salts are widely used in
commerce.
CHEMICAL OXIDATION AND REDUCTION
Description of Process
Chemical oxidation or reduction is an effective method for converting
certain types of hazardous reducing or oxidizing materials to less
hazardous or nunnazardous materials.(43,44,49-51) jn the latter case it
is considered as an ultimate disposal method by itself. Redox reactions
are perhaps more frequently used as a pretreatment step to produce a less
hazardous material as in the case of reduction of very toxic Cr+6 to
less toxic Cr+3, which can be precipitated as chromic hydroxide.
A variety of chemical reagents are available for the oxidation of
selected hazardous materials; and the choice of a particular oxidant
usually depends on: the oxidizing power needed, safety, cost, and
availability. Oxidants frequently employed for treating hazardous wastes
include: sodium and calcium hypochlorite, chlorine gas, ozone, and
hydrogen peroxide. Electrolytic oxidation is also used by industry;
however, electrolysis has very limited utility in the field, as does the
use of chlorine gas or ozcne, which also require special application
equipment. Sodium hypochlorite, calcium hypochlorite, and hydrogen
peroxide are widely available and merit first consideration for in situ
spill treatment or make-shift field treatment units. Oxidation of highly
toxic cyanide with chlorine gas or hypochlorite salts is a classic example
oxidation of a hazardous material to innocuous end products, e.g., CO?,
^2, and H20. Care r.iust be exercised to avoid overuse of chlorine or
reagents containing hypochlorite since these are highly toxic to aquatic
organisms. Hydrogen peroxide is a useful oxidant that has a low toxicity
when diluted.
Chemical reductants that are widely available include ferrous
sulfate, sulfur dioxide, and sodium sulfite. Sulfur dioxide is a gas at
arnuient temperatures and would be difficult to apply in most field
situations.
The reduction of very toxic Cr+6 to Cr+3 represents one of the
most important oxidation/reduction reactions. Chromates and dichromates
are widely used in the metal plating industry, in cooling tower water
conditioning, in the textile industry as mordants, in pigments with
barium, lead, molybdenum, and zinc compounds, in chrome tanning operations
as sodium dichromate and in the photographic industry (often as ammonium
chromate or bichromate) for accelerating development and for hardening
gelatin and in the manufacture of lithographic plates.
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Two disposal methods are now practiced for Cr+6 compounds. Both
methods reduce the Cr+6 to Cr+3 by addition of SOj, flue gas, sodium
sulfite or metabisulfite, iron filings or brass or aluminum turnings from
machining operations. Where tne Cr+3 concentration is very low it may
be directly disposed to the sewer. In the case of high Cr+3
concentrations, the solution is pH-adjusted to 9.5 and the metal hydroxide
is precipitated. The chromium hydroxide sludges are, however, high in
water content (80% H20 by volume) and require settling over long time
periods before disposal to a proper landfill operation.
Destructive chlorination or chlorolysis of organics can be considered
as a chemical oxidation technique. However, the carbon tetrachloride
product usually obtained by chlorolysis of organics is also a hazardous
material.
Assessment
Chemical oxidation or reduction is an ultimate disposal process that
should be used for the following hazardous materials whenever practicable:
cyanides chromates
hypochlorites permanganates
chlorates peroxides
sulfides hydroxylamine
sulfites nitrites
Reducing hazardous materials such as cyanides, bisulfite, sulfite,
bisulfide, sulfide. iiydroxylanine, nitrite, and sulfur dioxide can be
oxidized to nonnazardous substances with chlorine or hypochlorites. Care
must be exercised in using hypochlorites or chlorine to avoid an excess.
Solutions containing 5% sodium hypochlorite (common bleach solution) are
readily available at grocery stores at about $0.40 per liter. The use of
hydrogen peroxide may be preferable for the oxidation of sulfides,
bisulfides, sulfites, bisulfites, and sulfur dioxide. Sodium sulfite or
bisulfite are recommended reducing agents for hazardous oxidizing
materials such as hypochlorites, chlorine, hydrogen peroxide, and
permanganate. Variations in substrate materials will have little effect
on this process other than to change overall reagent requirements. For
instance, the presence of large amounts of organic solids could greatly
increase the demand for oxidizing agents in an oxidation process.
LOW-TEMPERATURE FIXATION
Description of Process
The disposal of toxic liquids or sludges into land disposal sites can
lead to problems witn groundwater contamination from leaching by nacural
precipitation and airborne contamination from windblown dust. Low
temperature fixation of wastes by mixing with asphalt, sulfur, tar
polyolefins, or epoxy resins encapsulates the wastes and prevents them
from leaching by rain water or dispersion by wind. Organic binding agents
are primarily hydrophabic in nature and many of them do not function well
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in a high moisture environment. These agents also suffer from ultraviolet
light and microorganism instability. Inorganic solidification systems using
various silicates in conjunction with proprietary constitutents have been
developed by several companies in the United States.(52,53) These
solidification processes have been applied to the ultimate disposal of SOX
power plant scrubber sludges.(54) Sulfate sludge is fixed in two steps
taking up to 72 hr. The first produces alkaline earth sulfate or sulfite
compounds, usually typified by a fibrous gypsum. The second reaction involves
cement-like reactions between fly ash a'.umina and silica, lime compounds and
sulfur oxide salts.
For fixation, the SOX sludge can be dewatered and mixed with dry fly
ash without any other additives . Soluble silicates and silicate-setting
agents can also be used to solidfy a wide range of liquid and sludge wastes.
The solids from the above processes are reported to have permeability
coefficients on the order of 1C-6 to 10-7 cm/sec (at 10-6. water
nominally takes 1 year to penetrate 30 cm).(55) Consequently, leach rates
of metals and other toxic inorganic materials contained in the original sludge
or liquid are very low. Long-term leaching results for the cited fixation
products are lacking. Extensive leaching tests have shown that the leaching
rates are generally low for these solids although all do leach pollutants to
some degree and may disintegrate as a result of weathering. Electroplating
sludge used hy Mah"loch(56) in his testing program showed that leaching
characteristics of the solids as compared to the raw sludges were a function
of the ion that has been fixed. Calcium, for example, showed little
difference between leach results on the raw sludge and three different
solidification-process solids. Cadmium, on the other hand, leached at a much
slower rate for all three solids than for the raw sludge.
Wiles and Lubowitz(57) described a process that uses polybutadiene as a
binder resin for encapsulating dry hazardous wastes. The process consists of
dewatering the waste, coating the particulates with polybutadiene resin in a
solvent, removing the excess solvent, agglomerating the resin-coated
particulates by compaction, and curing the thermosetting material, which may
then be jacketed with polyethylene into 230 to 460 kg blocks of waste. About
4 wt% of polybutadiene was required for coating and binding waste particulates.
The amount of polyethylene used depends upon the desired jacket thickness.
Immersion of several encapsulated wastes in distilled water, seawater NH/iOH
citric acid, HC1, and NaOH for up to 120 days showed minimal leaching of heavy
metals (Cu, Cr, Zn, Cd, and Hg) and calcium but somewhat greater leaching of
sodium. Monosodium methane-arsenate encapsulated by this process leached less
than 0.01 mg/L, as after 80 days in distilled water and 1.5 m NH4C1. The
cost of the process was estimated at $100/dry metric ton (tonne) of waste
(4 wt% polybutadiene coating and binder and a 0.64-cm thick polyethylene
jacket on a 360 to 460 kg waste block). Yearly throughput of 18,000 tonnes
and the use of commercial resins was assumed in the cost estimate. The
authors point out that, though the process is expensive, there are very few
alternatives that allow ultimate disposal of toxic inorganic wastes, such as
arsenic, in a lai.dfill operation.
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Replacement (substitution) reactions of one cation for another in a
mineral (say Ba"1"'' for CA++ in apatite, which is relatively insoluble
(S)8)) is one approach for fixing heavy metals. Apatite (Ca5(OH)
(P0/i)3) may be formed as follows:
NaOH + 3 Na3P04 + 5 CaCO-p* Ca5(OH)(P04)3 + 5 Na^O,.
The C.iC03 can be placed in a column and the Na3P04 added to the
influent. Approximately 38 rng/L P0z[3 are required for the reaction
to proceed. As the replacement occurs, barium and other cations that fit
into the forming apatite crystal structure are removed from solution into
the relatively insoluble apatite. Very high decontamination factors
between column influent and effluent are possible.
Fixation processes have generally focused on containment of inorganic
species. A few fixation agents appear to be effective for organic
substances. Epoxy resin and polymeric sulfur binders, for example, were
useful in reducing the Teachability of Kepone-contarninated sediments.(59)
Polymeric silica cements were not effective since the higher alkalinity of
these cements tends to solubilize the Kepone.
Assessment
Fixation processes, which convert hazardous materials to nonhazardous
materials by reducing the leach rate to an acceptable level, are reviewed as
ultimate disposal methods although actual disposal may take place in a
sanitary landfill. Heavy metal sluages containing the hydrous oxides of Fe,
Ni, Cu, Zn, and Co fit in this category; however, final determination of
utility must await the development o* landfill disposal standards. Little
work has been done on fixation of organic wastes and that alternative is not
recommended at this time. In this report, fixation processes that convert
hazardous materials to less hazardous forms are considered to be
pretreatment methods. In this report, deposition of the fixed waste in a
secure landfill is classified as the ultimate disposal method.
Fixation agents must be selected carefully, usually through screening
tests. This is particularly true for the disposal of complex mixtures such
as spill residuals. The presence of trace contaminants can greatly affect
the integrity of the stabilization product. For instance, organic materials
have long been known to reduce the strength and longevity of concrete and to
enhance weathering. Concrete is arialagous to the Portland Cement-based .
fixation mixtures. Similarly, some inorganic salts can prevent a good set.
Consequently, preliminary testing of proposed agents is necessary, and
long-t°rm evaluation is advisable.
SANITARY LANDFILL
pescrvjtiori
A sanitary landfill can be defined as a land disposal site employing an
engineered method of disposing of solid wastes on land in a manner that
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minimizes environmental hazards by spreading the wastes in thin layers,
compacting the solid wastes to the smallest practical volume, and applying
cover material at the end of each operating day. Landfills occupy a niche
between the surface disposal of wastes such as for sewage sludges ana the
deep burial or geologic storage of extremely hazardous wastes.
Landfill operations are characterized by the two functions of maximum
utilization of the soil adsorptive properties and the storage of wastes in
a manner to promote isolation from man and his environment. Some liquids
end slurries have been disposed into landfills, Out the potential for
leachate migration exists even in well-designed and operated sanitary
landfills. Study and selection of a landfill site minimizes use hazards
although the escape of hazardous gases such as cyanide always is possible
through tne indiscriminate mixing of wastes. Certain wastes such as
soluble heavy metals, salts, and other water soluble, toxic material
should not be disposed to sanitary landfills. Additional precautions over
and above tnose taken during sanitary laudfilling of municipal solid
wastes are required for ultimate land disposal of hazardous wastes. Tne
sanitary landfill should be limited to disposal of inert solid wastes
(nonhazarcous) that do not constitute a threat to the water quality ot
adjacent areas. Examples of the types of wastes that might be disposed
to a sanitary lanofill include calcium sulfate-calcium fluoride wastes
from the fertilizer industry and slag from some smelting operations if the
slag is in tne form of a glass containing no soluble heavy rnetal
compounds. Codisposal of industrial wastes with municipal wastes in
sanitary landfills nas caused problems. Consequently regulatory agencies
in tne early 1970's initiated campaigns to segregate these wastes.(°0)
The high organic content of municipal solid waste results in
biodegradation processes tnat can lead to solubilization and subsequent
migration of heavy metals, for example. Indiscriminate mixing or solid
wastes can also cause chemical reactions that, are detrimental to
containment of tne wastes. Sanitary landfills were reviewed by
LiptakU'l) in relation to site selection and preparation, environmental
impacts,, ana utilization.
Assessment
Sanitary landfills represent one of the most widely used ultimate
disposal metnods currently practiced in the United States. The use of
sanitary landfills for burial of anything is presently diminishing to some
extent as coTjnunities recognize the problems associated with burial of
some types of hazardous materials at these sites. Nevertheless it is
expected that sanitary landfills will continue to be extensively used for
hazardous spill residuals which can be disposed via this route. The
latter determination will depend heavily on pending hazrvdous waste
regulations, which may preclude this option entirely, ,''~terials amenable
to this method of disposal include materials that are not designated as
hazardous by regulatory agencies and would not be a potential problem in a
sanitary landfill. Vegetable oils and relatively innocuous inorganic
salts such as sodium phosphate and aluminum chloride or sulfate are
examples of materials which could be placed in a sanitary landfill. Large
volumes of soil or other inert substrates contaminated with low levels of
spill residuals would also be likely candidates for sanitary landfill
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disposal. From a technical viewpoint little or no impact on the
environment surrounding the landfill would be anticipated since normal
usage of the landfills would far overshadow the infrequent use of a
particular sanitary landfill for disposal of some types of hazardous spill
residuals. The social impact must be considered, however, since the
public's image of hazardous materials can be a strong deterent to *he
disposal of residuals that can be safely placed in a sanitary land-fill.
Great caution is needed when sanitary landfills are used in tte
disposal of hazardous wastes. The action of precipitation (rainfall) has
been a major factor in solubilizing hazardous wastes and causing pollutant
migration and groundwater contamination.
Sanitary landfills are widely available at reasonable costs. The
range of costs for sanitary landfills processing less than
45,000 tonnes/yr(44) is $1 to 6 per tonne (1973 costs). Burial in large
size landfills ranges from $0.68 to $1.82 per tonne.
SECURE LANDFILL
Description
In addition to the simple requirements for a sanitary landfill, a
secure landfill requires that the site be geologically end hydrologically
well-characterized and approved for the disposal of extremely hazardous
wastes.(44, 62-64) The site must allow for no discharge of the liquid
or solid wastes or their byproducts to ground or surface waters by
leaching, percolation,or any other means. Air quality also must not be
compromised. Chemical interactions are to be avoided by keeping records
of amounts, types, and locations of disposed cnemicals. Provisions for
leachate monitoring, and collection if necessary, have i,o be provided for
at the secured landfill.
Inputs to the secured landfill site selection process include
determination of average rainfall and rainfall patterns in the area and
the construction of i site wind rose.(64) Population distribution
around the disposal site should be compared with prevailing wind
directions. Tne geological and hydrological field conditions can be
obtained from local sources and through a. program of drilling. Soil and
iock data, as well as information on the depth, occurrence, and quality of
groundwater, should be obtained. When impervious basins are desired,
suitable artificial or natural liners must be designed; examples include
clay layers and plastic liners. The life of the liners snould be
investigated under the contemplated conditions of use but acceleratad
life-testing is difficult and controversial. Water-soluble materials of
high hazard potential may require asphalt caps, as well as plastic
liners. Specific requirements for siting and operating secure landfills
have been proposed oy the U.S. EPA(5) and have already been estaolished
in several states. Capping or covering a filled, secured landfill is
essential, as is maintenance of the cover's integrity. Cap cracking,
erosion, and gullying readily allow precipitation to enter the fil1. and
enhance backing and migration of stored pollutants.
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A secured landfill (e.g., Class I site in California) is a large pit
into which any liquid or solid compatible waste may be disposed. One
type of secure landfill is illustrated in Figure 10, Examples of hazar-
dous chemicals that can be disposed to a Class I site include aluminium
fluoride, antimony pentasulfide, antimony sulfate, antimony trisulfide,
nitrochlorobenzene, selenium metal, thailium metal, thallium sulfate, and
small amounts of the metal arsenates and arsenites.(44) Many heavy
metal hydroxide sludges, resulting from hydroxide treatment of soluble
heavy metal salts, also may be disposed to secure landfills.
The requirement to control drainage through the disposal site either
limits the location of a secure landfill to arid or semiarid western
regions or requires an elaborate system for recovery and treatment of the
infiltrate solutions. Though the initial preparation and operating costs
are higher for the secured landfill than for the sanitary landfill, the
variety of wastes that can be safely disposed is much greater than those
in a sanitary landfill. A secure landfill should not, however, be
considered as a disposal site for all types of hazardous wastes. For
example, California's largest sanitation agency, the County Sanitation
District of Los Angeles County, has banned the burial of concentrated
cyanide wastes at its Class I landfills in order to prevent dangerous
levels of cyanide gas from being created in the working area of these
landfills.(65) One must also be concerned with comingling in a secured
landfill of wastes that may react violently or produce highly toxic and
mobile gases. For instance, the introduction of acids to landfills
containing sulfides or cyanides can result in the release of toxic clouds
of hydrogen sulfide or hydrogen cyanide.
Proposed RCRA regulations on hazardous waste disposal include
requirements for record keeping and reporting (manifest system) and the
monitoring of groundwater and leachate from landfills. The location with
respect to permanently surveyed bench marks must be recorded for each type
of waste disposed in a secure landfill. A groundwater monitoring system
consisting of at least four monitoring wells must be maintained. One or
more wells must be located in an area hydraulically up-gradient from the
landfill and three or more wells located down-gradient. At least one of
the latter three must be located immediately adjacent to the active
portion of the landfill. Sampling and analysis schedules will be
established by State regulatory agencies or the EPA.
Assessment
The disoosal of highly toxic hazardous material spill residuals in
secure landfills represents an improvement over disposal of these
residuals in sanitary landfills. Although chemical destruction, including
incineration, is recommended as first priority where possible, it is
recognized that landfilling will be less costly or the only alternative
available in many incidences involving disposal of spill residuals or
releases. Disposal of persistent hazardous substances such as chlorinated
hydrocarbon pesticides and toxic heavy metals in a well-designed and
engineered secure landfill should provide adequate containment of these
materials as long as sufficient control is exercised over operational and
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Monitoring i
-.veil
Monitoring
well
FIGURE 9. Example of a Secure Landfill
retirement procedures. However, questions arise as to the consequences of
eventual abandonment of the site and loss of control at some future date.
(These problems are addressed in "Superfund" legislation (CERCLA, P.I.
96-510). Would the waste hazardous materials buried in a secure landfill
represent severe problems with respect to tne health and well-being of
future generations? This question has been hotly debated in the case of
ultimate disposal of radioactive wastes and many consider it an important
question with regard to persistent, highly toxic chemical wastes. Control
over a waste burial site cannot be maintained "forever". The burial site
markers can be destroyed or removed by acts of vandalism, for example.
Records can be lost or destroyed. Climate changes may occur whereby
rainfall increases substantially in a formerly arid region. The stability
of governments is rarely guaranteed for more than a few hundred years.
What happens if--in the distant future—an old, large secure landfill
becomes unwittingly exposed to dispersive forces by either natural events
or oy the ?ctions of man? Any number of scenarios can be written whereby
human health and welfare would suffer or devastation of the environment
would occur.
The debate over ultimate disposal of radioactive materials has
resulted in a more restrictive policy concerning landfilling of
radioactive wastes. Only low-level, relatively short half-life
radioactive waste is now buried in secure landfills. The U.S. Department
of Energy is presently embarked on a major program to convert high-level
radioactive wastes to materials, such as glasses, with very low leacn
rates and to dispose of these materials in geological formations that
provide a high degree of confinement. Hazardous, long-lived radio-
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nuclides—such as transurcmic isotopes--are also designated for disposal
at sites where isolation is assured for very long periods of time.
The restrictions that have been appliec to the disposal of
radioactive wastes could also be applied to those chemical wastes that
exhibit a similar degree of hazard. The need to establish such
restrictions for chemical wastes has not been demonstrated as this report
is being prepared. The EPA Office of Solid Waste Management Programs has
suggested that wastes bearing toxic heavy metals, such as arsenic and
cadmium, may safely be disposed in a properly designed and operated
landfill; ultimately, any decision regarding the environmental adequacy
and safety aspects of land disposal of a given waste material must depend
on one overall analysis of the individual situation.
A second line of defense against transport of hazardous materials
fran a secure landfill is warranted for the extremely toxic materials such
as soluble arsenic compounds. An effective fixation method—if indeed
"effective" can be defined—is a potential approach to assure confinement
of these materials in a landfill. Leachate control systems that prevent
infiltration of water may also be required to maintain confinement of the
waste.
Seven states were renorted to have secure landfills in 1977.(66)
Additional states such as Oregon have since then joined the list. A map
snowing the location of these sites is given in Figure 11. The cost of
sec (re landfilling of hazardous v/astes can be of ^e order of ten times
that for common sanitary landfilling.
DEEP WELL DISPOSAL
Description
Deep well disposal represents an ultimate disposal system in which
waste water is pulped under pressure into deep wells and contained in a
permeable subsurface zone that is separated by impermeable rock strata
from the surface and subsurface useable aquifers.(67) when the
repository zone is dry or contains a noncommercial brine and the waste
remains with'-i the desired disposal section, then the technique is a
valuable one for ultimate disposal. However, tne potential for
environmental pollution is high for deep well disposal. Any number of
problems may result in the contamination of fresh water aquifers. There
is a lack of control of the wastes cfter they are injected. Because of
the expense of drilling several monitoring v.ells around the injection well
the monitoring of waste migration following injection is absent in many
cases. Even when unexpected migration or the waste material is detected,
there is no easy, low cost way to effectively recover the waste or halt
the migration.
To ensure that all of the migration potentials are known, it is
generally necessary to undertake a very expensive program of drilling and
regional hydrogeologic mapping. In addition, pretreatment facilities may
be needed before the waste can be injected. Deep well injection is
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00
LOUISIANA'.
\ MS-f^ggS^-----
\ 1
V /-Y
Figure 10, Location of
—b
-..I
Landfills in the United States
-------
limited to aqueous solutions tnat are compatible with the geological
formations into whicn the solutions are injected.
The suitability of wasf.e for underground injection depends both on
.its volume and physical and chemical characteristics and on the physical
and chemical properties of V t.> potential injection zones and their
interstitial fluids. Wastewa.-r that is suitable for injection must be:
1) low in volume and high in concentration, 2) difficult to treat by
surface methods, 3) free of any adverse reaction with the formation fluid
or the strata, 4| free of suspended solids, 5) biologically inactive, and
6) noncorrosive.(68,69)
Waste disposal into deep underground aquifers depends on the use of
limited storage capacity of the aquifer, and only concentrated, very
objectionable, relatively untreatable wastes should be considered for
injection. The fluids injected into deep aquifers do not occupy empty
pores as in the vadose (surface) zone, but displace the fluids that
saturate the storage zone. Consequently, optimal use of the underground
storage space will be realized by the use of underground injection only
when more satisfactory alternative methods of waste treatment and disposal
are not available.
Reaction of the wastewater with the formation water or the strata
must be considered. Resultirg problems include dissolving the formation,
generating a gas c*"~ precipitate in the formation, and clogging by
biological growths. Walker and Stewart(70) suggest a laboratory test to
ensure compatibility of the wastewater with the formation. The wastewater
is mixed in a beaker with a formation water sample and held at formation
temperature to see whetner there is any precipitate or adverse reaction.
Pumping the wastewater through a core sample can reveal possible clogging
problems. The wastewater should be free of suspended solids and
biologically inactive to avoid reservoir clogging. The corrosiveness of
the wastewater should be low to prevent tubing and pump corrosion.
Assessment
Deep well injection is a viable option for the disposal of aqueous
solutions of certain types of hazardous materials; however, there are
presently only 6 injection wells iaencified in the United States that can
handle hazardous wastes and three of them are located in Texas.(b6) The
lack of available injection sites coupled with the low probability of
encountering aqueous solutions that are acceptable for deep well injection
is expected to result in little use for this method of ultimate disposal
for hazardous material spill residuals. Concentrated brines from residue
treatment processes may be an exception. Some claim that disposal of
these solutions into existing brine aquifers can bypass expensive
evaporation processes without creating adverse impacts, but the subject is
controversial.
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OCEAN DISPOSAL
Description
The oceans have long been used by man as ultimate refuse disposal
areas, and have come into much greater use for wa^tc disposal with the
advent of industrialization. Many of our most hazardous wastes, such as
munitions and other martial tools, have been disposed by scuttling
obsolete munitions-loaded ships at sea. Various sludges and liquid wastes
are barged to sea and dumped. The liquid and solid wastes may be very
acidic or basic because the sea acts as both a diluent and a system pH
buffer allowing disposal of acids, bases and toxic materials.
Incineration of chlorinated hydrocarbons has been undertaken at sea in
special incinerator ships to take advantage of the buffering capacity of
the ocean without having to resort to caustic scrubbing of HC1 and to
minimize the ecological effects. The ocean dumping of radioactive wastes
has been severely curtailed. Improved packaging is required and the
dumping of high level radioactive waste is prohibited.
Certain areas of the Atlantic and Pacific Ocean:, and the Gulf of
Mexico have been designated as ocean dumping areas. However, with the
renewed interest in offshore oil drilling and manganese module recovery
from deeper ocean areas, the waste disposal and mining or drilling areas
of interest may begin to overlap. Consequently, a permit system was
initiated by tne Environmental Protection Agency. (^U There are several
permit categories for waste disposal including general, special,
emergency, interim, ?nd research permits. General permits authorize
dumping of nontoxic wastes in small quantities. Special permits are valid
for three years and allow dumping of materials not covered by the general
permit except toxic metals, oils, inorganic wastes, and BOD producing
materials. Emergency permits allow dumping of prohibited materials when
there is no other alternative disposal procedure due to emergency
conditions. Interim permits are used during development and execution of
other acceptable waste disposal plans. Research permits are granted when
the benefits of a project outweigh the potential environmental hazards of
ocean disposal of its waste products. The EPA will not allow dumping of
high level radioactive wastes, biological or other warfare agents, and
unknown materials or materials that persist in suspension. Stringent
requirements are maintained on dumping of organohalogens, cadmium,
mercury, and oils. Current restrictions are now supported by
international convention ana are the 3i>uject of further discussion and
probable tightening.
Assessment
Restrictions placed on ocean dumping of water have substantially
reduced the number of materials that can be disposed via this route.
Furthermore, only a few contractors located in six states across the
country have facilities available for ocean oumping. Although ocean
dumping is a viaole option for some hazardous material residuals, the lack
of available facilities and regulatory restraints limit the use of this
method of ultimate disposal.
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APPLICATION OF CONVENTIONAL DISPOSAL TECHNOLOGY
Spill Characteristics
Hazardous material spills and releases can occur under a wide variety
of conditions on land as well as in water and may involve small or large
quantities of material that range from essentially nontoxic to deadly.
Depending on the circumstances, spillage of a hazardous material may or
may not result in the formation of a hazardous waste requiring disposal by
methods set forth under Rf.RA. A moderate or small spill of highly volatile
material, e.g., liauefied petroleum gas (LPG), will usually evaporate and
disperse to the atmosphere leaving little or no residue. A spill of
soluDle material in a large rapidly flov.'irg stream may be so quickly
diluted and dispersed that nothing can be recovered for disposal. In many
cases, especially for spills on land, the release or spill residue may not
be considered hazardous and disposal to a sanitary landfill or municipal
sewage treatment plant would be permitted. Common, low-toxicity materials
such as ri/ethanol, ethanol, acetone and other readily biodegradable
organics (corn syrup) can be disposed at a municipal sewage treatment
plant or, in some instances, simply allowed to drain into soil where
natural biological degradation will take place. Hazardous materials mixed
with soil will frequently be rendered nonhazardous because of
neutralization or fixation by the soil. Spilled strong acids such as
sulfuric or hydrochloric that percolate into soil will generally be
neutralized by the soil. Ammonia spilled in water is toxic to fish but
ammonia spilled on land may be readily sorbed by soil and not create much
of a problem. Designation of a spill residue as hazardous will depend on
criteria and tests to be established by regulatory agencies. Proposed
criteria can be found in the Federal Register, Volume 43, No. 243 -
Monday, December 18, 1978.
Admixture of spilled hazardous material with extraneous matter will
frequently dictate the type of disposal method to be used. Four basic
types of mixtures were considered in determining the type of disposal
needed:
- Mixtures with minor amounts of extraneous matter,
- Mixtures with or solutions in water,
- Mixtures with combustible material,
- Mixtures with noncombustible material.
Recovery and reuse of spilled hazardous material should be undertaken
whenever possible. In many instances, mixtures with minor amounts of
extraneous matter may be processed for recovery of the spilled material.
Recovery of spilled oil is often practiced since extraneous matter mixed
in oil can frequently be separated without much difficulty. When recovery
is not practical, disposal of spill residuals mixed with minor amounts of
extraneous matter can generally be accomplished in a manner similar to
that recommended for the pure material.
Mixtures or solutions in water constitute a separate category because
processes such as gravity sedimentation, absorption, ion exchange or
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precipitation are frequently used to remove the spillea hazardous material
from the water. In some instances (e.g., caustic spills), the spilled
hazardous material may be disposed by neutralization in the aqueous
solution. Materials removed from water are subject to appropriate
disposal methods.
Mixtures of spilled hazardous materials with combustible matter are
placed in a separate category from those with noncombustible matter since
incineration is a viable option when the mixture is combustible and
degrades to suitable end products. In case of mixtures between categories
(e.g., a spill mixed with both combustible and noncombustible matter),
judgment is necessary in selecting an appropriate disposal method. For
example, a sizeable fraction of noncombustible matter in a large quantity
of spill mixture may render the whole mixture unsuitable for
incineration. Mixtures of water with insoluble combustible or
noncombustible matter may be either settled, screened, or filtered to
remove the water.
Method Evaluation Matrix
A matrix was prepared to aid in evaluating conventional disposal
technology for spilled hazardous materials. The initial approach to
preparing such a matrix included classification into families for chemical
compounds that possessed the same or similar chemical and physical
characteristics. Disposal methods were to be selected and evaluated for
each of these separate classifications. This approach was abandoned,
however, because trie number of classifications was too large and did not
adequately focus attention on problems associated with disposal of highly
hazardous, persistent materials.
An alternate approach was adopted whereby spilled hazardous wastes
are divided into two categories, organic and inorganic. The organic
materials are subdivided into reactive, unreactive, and highly-toxic
persistent whereas inorganic materials are subdivided into reactive and
highly-toxic persistent. The evaluation matrix presented in Table 3
utilizes these five categories of hazardous materials combined with the
four basic mixtures with extraneous matter discussed in the previous
section. Only materials designated as hazardous waste under proposed RCRA
regulations are included in these categories. Spill residues that are
rionhazardous may be disposed of by conventional methods such as sanitary
landfills or municipal solid waste incinerators.
The subcategories "reactive" and "unreactive" pertain to the ease
with which the materials can be biochemically or chemically treated to
form less hazardous or nonhazardous materials. Reactive materials can be
treated in situ at the spill site or recovered and treated by methods
presented in the User's Manual for the Control and Treatment of Hazardous
Material Spills.(45) Treatment, designated by the letter "B" in the
matrix, includss biochemical arid chemical methods that may either occur
naturally or be induced by personnel responding to the spill. Unreactive
materials cannot be readily altered to less hazardous or nonhazaidous
forms by simple aqueous chemical or biochemical methods and are either
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incinerated (designated by letter "0" matrix) or disposed to a secure
landfill (designated by letter "S" in matrix). Diluted materials in
aqueous solution may be concentrated by chemical or physical
methods.
TABLE 3. MATRIX FOR CONVENTIONAL DISPOSAL METHODS
Hazardous
Composition Hazardous Organic Waste Inorganic Waste
Reactive
Mixture with
minor amounts of
extraneous matter
Mixture with
substantial
ainount of water
Mixtures witn
combustible
solids
Mixtures with
small non-
combustible solids
8
0
S
A-B
A-0
A-S
B
0
B
S
llnreactive
0
S
A-0
A-S
0
S
S
Highly Toxic/ Highly Toxic/
Persistent* Reactive Persistent*
0
S
A-0
A-S
0
S
S
B F-S
3 A-F-S
B F-S
B F-S
B = Treatment (biochemical or chemical)
0 Incinerate
S = Secured Tandfill
F Fixation
A = Concentrate and remove from water
* = See Appendix A for listing
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(designated by letter "C" in matrix) to cleanup the water and reduce the
residue to a small volume for disposal. The method used to concentrate
the hazardous material may also render tilt material nonhazardous.
Adsorpti'ji of the material on activated carbon, for example, may fix the
material 50 that it is nc longer leachatle at hazardous levels. As
previously discussed, precipitation can be used to remove and concentrate
hazardous materials for disposal but the precipitate may or may not
qualify as a hazardous material, depending on the solubility of the
precipitate and the toxicity of the hazardous constituent contained in the
precipitate. Disposal methods are listed from top to bottom in order of
preference.
The highly toxic, persistent subcategory includes organic materials
that are unreactive and persist in the environment beyond one year and
represent an especially great hazard due to unacceptable levels above
1 mg/L in water. This category of organic hazardous materials includes a
number of pesticides that represent a substantial threat to the
environment when not properly disposed. Inorganic highly-toxic,
persistent materials are limited to substances containing sufficient
leachable arsenic, barium, cadmium, chromium, mercury, lead, selenium, or
silver to qualify as hazardous. The list of hazardous materials in
Appendix A also includes information concerning amenability to biological
or chemical treatment or incineration and designates those materials in
the highly-toxic, persistent category and those defined as nazardous or
potentially hazardous under proposed RCRA regulations.
Chemical treatment indicated in the matrix presented in Table 3 is
limited to: 1) neutralization with acid-j and bases, 2) oxidation and
reduction at atmospheric pressure with common oxidants and reductants such
as nypochlorite and sulfite, and 3) precipitation. Chemical or physical
fixation is included only for inorganic material since this method is not
considered to be a conventional tecnnique for organic material. Ocean
disposal and deep-well injections are not included because of anticipated
restrictions on these disposal methods.
A discussion of the matrix in Table 3 is provided in the following
subsections for eacn of the subcategories of hazardous materials as
applied to the four basic mixtures.
Organic-Reactive. This subcategory includes many materials that can
be decomposed to innocuous end products by biological or chemical
treatment methods. Reference to the User's Manual for Control and
Treatment of Hazardous Spills(43) is recommended to determine the type
of treatment for a particular material. Materials not listed in the
User's Manual including industrial process or waste mixtures will require
judgment on the part of the On Scene Coordinator (OSC) to select the
proper method. Similarity to materials listed in the manual can be used
as a guide in selecting a specific method or methods. Consultation with
experts in the field can hardly be overemphasized to assure selection of
appropriate methods.
Hazardous wastes that can be readily biodegraded include aliphatic
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acids, acetone cyanohydrin, phenol, formaldehyde .Md many others listed in
Appendix A. Dilution and neutralization of the spill residue may be
accomplished by one or more of several different methods. The organic
substances listed abova that biodegrade readily can usually be discharged
to a biological treatment plant under controlled conditions to avoid
overloading tne plant. Alternately, in situ biodegradation is frequently
possible by allowing the material to remain in the soil into which it
drains from a spill site. This approach is possible where there is no
threat to ground or surface waters or to personnel in the vicinity of the
spill. Chemical methods should be given priority where possible for
reactive materials that are hignly toxic to quickly ameliorate the effects
of the spill. Incineration is considered applicable to all hazardous
organic materials except organometal1ic substances such as tetraethyl
lead. Although incineration has not been evaluated for all the organic
compounds listed in Appendix A, it is assumed that, with proper
temperature control ana residence times in the incinerator coupled with
suitable scrubber/filter systems, incineration represents a viable
disposal alternative for these materials.
The availability and cost of operating incinerators are the principal
limitations to widespread use of this method for disposal of spilled
hazardous materials. As e consequence, chemical or biological treatment
is given preference over incineration for the Organic-Reactive group of
materials.
Disposal in a secure landfill is the third option that can be used
althougn priority is given to the first two options, treatment and
incineration, which destroy and eliminate the spilled material. However,
in this subcategory there are a number of materials that will
anaerobically or chemically degrade in the landfill and would not present
long-term problems. Alcohols, aldehydes, ketones, carboxylic acids, and
carbohydrates are examples of materials that undergo relatively rapid
anaerobic decomposition. (Petroleum-based oils are not good candidates
for anaerobic decomposition although landfilling is a comnioi disposal
method for these materials. Landspreading for the more rapid aerobic
decomposition process is the preferred method. Waste oils are designated
as hazardous.)
A discussion of disposal options for each of the basic types of
mixtures under reactive organic hazardous waste is presented below:
1. Mixtures with minor amounts of extraneous matter. Methods outlined
'in trie user's Manual (43) are appropriate for most of the materials
in this group insofar as treatment by disposal is concerned.
Treatment is generally the preferred option followed by incineration
and then secured landfilling. Contaminated petroleum-based oils,
which represent a large fraction of the total spills, would in the
majority of cases be recovered rather than disposed when containing
only minor amounts of extraneous matter. Oils not recovered follow
the priority of: 1) treatment by land spreading, 2) incineration,
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and 3) landfill ing. In order to reduce the mobility of the oil for
landfilling, the oil should be absorbed in some porous material prior
to disposal. Whether oils mixed with absorbent materials constitute
a hazardous waste in all cases is uncertain. Regulated quantities of
oily material may be disposed in sanitary landfills rather than in
secured landfills.
2. Mixtures with water. Methods outlined in the User's Manual for
Control and Treatment of Hazardous Spills will be appropriate for
most of the materials in this group since the methods assume the
presence or use of water. No further action is required when
treatment renders the material nonhazardous in the water (e.g.,
neutralization of acids and bases). However, many of the materials
may be removed from the water by sorption methods and the sorbent
containing the spill residue will require disposal. Hazardous
materials sorbed, precipitated, or ion exchanged from water may be
disposed by chemical or biological treatment, incineration, or
secured landfilling. An oxalic acid solution, for example, may be
neutralized with lime to precipitate calcium oxalate, which can be
biologically degraded, incinerated, or landfilled. Activated carbon
adsorption is commonly used to remove organic materials tnat have
limited solubility in water. Very soluble substances cannot be
readily adsorbed by activated carbon but will undergo rapid
biological degradation when sufficiently diluted in water. Dilution
with water may also render the material nonhazardous. Oil-water
emulsions are prereraoly treated by land spreading although
incineration is possible (e.g., but supplemental fuel nay be
required) and landfilling may be permitted when the waste is mixed
with sorbent material.
3. Mixtures with combustible solids. All three disposal options may be
used with these mixtures^The choice depends on: the nature and
toxicity of the spill residue, the availability of facilities or
equipment, and the characteristics of the combustible solids. Large
objects (e.g., wooden items) contaminated with soluble, low-toxicity,
reactive organic spill residues may be rinsed with water with the
rinse water then being routed to a biological treatment facility or
spread on land (if suitable acreage is available). Small objects
(e.g., grass, sawdust) contaminated with these same substances may be
treated by land spreading (if volatility is not a problem) or placed
under water in a biological treatment lagoon. Water-insoluble
materials such as oily wastes can be disposed by land spreading even
when the waste is mixed with small objects. Large objects are best
removed.
4. Mixtures with noncombustible solids. The presence of substantial
amounts of noncomoustible solids normally rules out incineration as
an economic treatment option. The utility of chemical or biochemical
treatment and secure landfill disposal are essentially the same as in
3.(above).
Unreactive Organic Hazardous Wastes. These materials cannot be
chemically or biochemically treated by conventional methods; therefore,
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disposal is normally limited to incineration or secured landfilling.
Since the hazardous constituents of these wa-stes are persistent,
incineration is muc.li preferred over secured landfilling . Disposal of
mixtures in this category by incineration and secured landfilling will be
similar to that in the "reactive organic" category except dissolution in
water will generally be more difficult.
High-Hazard Persistent Organic Waste. Disposal is also limited with
little opportunity for cnemical and biochemical treatment ana even more
emphasis is placed on incineration as the preferred disposal method.
Secured landfilling is not considered to be an acceptable long-term
disposal method for these substances; however, it should oe is recognized
that mixtures of these substances with extraneous matter complicates
alternate disposal methods. Further research and development is needed in
this area to estaolish suitable alternatives to landfilling.
Hazardous Reactive Inorganic Wastes. For these wastes, the use of
incineration as a disposal method is exclucied but fixation processes may
be useful especially where fixation can be demonstrated to produce a
material that is stable for an inctefinite tinv period under conditions
present or anticipated at the disposal site. A discussion of the disposal
of each type of mixture is presented below:
1. Mixtures with minor amounts of extraneous matter. Treatment to
"3estroy the hazardous substance is tne nreferred option in this
subcattgory. Neutralization of strong acrJs and alkalis are common
examples of this type of treatment. Residuals following such
treatment are usually nonhazardous. When hazardous residuals are
produced, further treatment is required. Oxidation of cyanide is
included as a disposal method in this subcateoory.
Disposal of reactive substances such as antimony pentachloride
requires special attention since the hazards are associated with the
violent reactions expected and the toxic gases (e.g., HC1) that may
be evolved.
2. Mixtures with water. Treatment is similar to (1) above except
IHJtistances that react with water need not be dealt with unless a
hazardous residual (such as HC1) remains.
3. Mixtures with combustible solids. Treatment and disposal may require
rinsing with water to remove "Lh,:- hazardous suostance for trar.sfer to
a vessel for better control of the chemical reaction. Oxidation of
cyanide may be inhibited by the presence of combustible matter, which
may be oxidized preferentially. Neutralization of acids and alkalis
may be accomplished in a mixture when qood mixing or contact with the
neutralizing agent can be achieved and excessive heat release
control led.
4. Mixtures with noncombust.ible solids. Treatment and disposal is
similar to (3) above; nowever, noncombustible solids such as sano are
more ir.erz and may not interfere with the reaction. Soil is
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considered noncombustible but may contain material that would interfere
with or participate in oxidation/reduction reactions.
High-nazard Persistent Wastes. These wastes contain the hazardous
heavy metals (As, Ba, Cd, Hg, Pb, Se, Ag). low-temperature fixation arid
secured landfill ing are the disposal methods commonly employed.
Low-temperature fixation methods may not achieve the ver/ low leach rates
needed for safe, long-term storage; therefore, further research and
development is recommended to establish superior waste *orms for
disposal. The presence of organic matter may inhibit fixation. Effective
separation techniques are also needed to remove these rretals ions or
complexes from extraneous matter.
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SECTION 6
THE HAZARDOUS WASTE PROCESSIf!fJ INDUSTRY
Previous segments of tnis report have been dedicated to a discussion
of technological options for disposing of hazardous wastes. Little,
however, has been directed to suggest who should execute those processes.
There is, in fact, a hazardous waste industry that specializes in doing
just that. In a recent review of the industry, Lehman(72) reported
that, In 1975, there were 95 firms operating 110 sites in the United
States. Some 57% of these firms are privately owned Vii.ile the remainder
are publicly held, either directly or through parent corporations. Only
8% of the firms are municipally owned; they are in California. Employment
in the waste processing industry is estimated at 2,000, 11% of which
positions are classified as professional. The capacity of the industry
was judged to be 6.6 million tonnes per year in 1975; r.owever, only 73% of
that capacity may be deemed environmental ly acceptable as disposal
feyuldlions come on-line. It is further estimated that only 53% of that
capacity is presently being utilized. Hence, the industry can readily
accept residuals from spill clean-uo activities at this time. This
situation may reverse itself with promulgation of proposed RCRA
regulations. Projected volumes of regulated hazardous wastes will exceed
current capacity.
There are compelling reasons why the hazardous waste industry should
be employed as the first alternative for disposal of :pill residuals:
1. The operators are experienced in the handling, treatment, and
disposal of these materials and can therefore minimize the risk of
improper management;
2. The organizations have the facilities and equipment available to
perform the necessary processes in an expeditious Banner; and
3. Regulations to be promulgated under the Resource Conservation and
Recovery Act will soon require that disposal of hazardous wastes be
conducted only at permitted facilities found to meet specific
standards.
The U.S. EPA's, Office of Solid Waste Management Programs issues a
periodic index of "Hazardous Waste Management Facilities in the United
States." This pamphlet gives a brief synopsis of the capabilities of
operating firms and describes the kinds of wastes that they can accept.
Facilities identified in 1977 are located on the map in Figure 11.
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It must be noted that wnile the hazardous waste industry should be
the first choice for management of spill residuals, it will not always be
the oest option. Use of existing facilities will often require
transporting spill residues great distances. This raises further risk of
spillage and exposure. Transport may be impractical or impossible if any
of the intermediate states that must be crossed refuse passage. Finally,
the state in which tne facility of choice is located must permit use of
that facility for the spill residuals. These problems are minimized when
an acceptable site is operating within tne state where the spill or
release occurs. Complications magnify with the distance between the spill
and the disposal facility, fts is evident from Figure 11, the greatest
difficulties coin be expected in the Rorky Mountain, Midwest and Southern
States.
Regardless of the latter considerations, the use of the hazardous
waste industry for spill residuals disposal is recommended whenever
possible. Upon characterization of wastes from clean-up activities and
confirmation that they are hazardous, the EPA index should be consulted to
determine tne nearest firms capable of handling these wastes. Contact
should then be made to ascertain the feasibility of using that site. Many
times the operator can provide properly equipped and placarded vehicles
for transportation to the site as well.
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.,._.... . ,fi
j '•»-•. /vil
(uiHtUSOIA "X.*-/^'
( V ~—
/ *'"'-^**o,.
;W-*_. /
/ 7"M/r-/
i u?
\ /
\. /.. /
\ .j4ii«o«v ;.._
P \ | /'<<>,
.-
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SECTION 7
NOVEL DISPOSAL METHODS
Novel disposal methods, which are in various stages of development,
were investigatea to determine their potential for ultimate disposal of
spilled hazardous materials. Emphasis was placed on disposal methods for
extremely hazardous and pers"itant materials.
THERMAL DESTRUCTION
Cement Kilns
Recent woric on the destruction of PCB's in cement kims(73) shows
promise of providing an alternate incineration method that would be much
more widely availaole than the waste incinerators currently designed for
this purpose. Normal operation of cement kilns is in the range of 1370
to K50°C with a very long gas residence of more tnan 10 seconds, more
than adequate for decomposition of most chlorinated hydrocarbons. The
alkaline substances in tne raw material feo to these kilns act as
efficient scruobsrs for the HC1 produced.
Two cement
-------
baths in which unwanted explosives and propellants are burned. Another
design(31) (Yosim, et al 1974) suggested the use of a soaium carbonate-
sodium sulfate molten bath to destroy organic pesticides at 900 to 95QOC.
The reaction becomes eAulnermic when the pesticide reacts with oxygen in
the air that is forced through the salt bath. Enough heat is generated to
keep the salt bath molten. Since molten salt incineration has had very
limited use in practical applications, more experience is required before
it can be properly evaluated for use with hazardous wastes.
Atomics International proposed that hazardous wastes, particularly
pesticide wastes including used pesticide containers, be combusted in a
molten salt furnace. Using a melt consisting of 90% sodium carbonate and
10% sodium sulfate and operating temperatures of 800 to 1000°C, 99.99%
destruction of DDT, 99.96% destruction of chlordane, and 99.98%
destruction of 2,4-D were obtained in a test reactor. No hydrogen
chloride or organic chloride could be found in the melt or the exhaust
gases as the halogens reacted with the salt to form sodiu-n halicies.
Phosphorus, sulfur, arsenic, and silicon form their respective oxygenated
sodium salts. This conversion to salts that remain in the nelt eliminates
the need for scrubbing required with other types of incineration.(40)
CHEMICAL DESTRUCTION
Bromiriation Process
The Atomics International bromination process is currently being
investigated for the disposal of orgaric spill residues.(74) Organic
materials are first reacted at a moderate temperature of about 300 C with
bromine and water to produce carbon dioxide and hydrobromic acid according
to the following equation:
CH + 2H20 + 5/2 Br2 > 5HBr (aqueous solution) + COz.
Off-gas from the reaction is stripped of HBr and excess Br£ and the
C02 is released to the atmosphere. Bromine is recovered from the HBr by
electrolysis by the following reaction:
5 HBr (aq. soln.) —•* 5/2 H2 + 5/2 Br2 (in dil. HBr soln.)
The bromine is returned for further reaction and the H2 is stripped of
Br2 and H8>" vapors prior to disposal or retse. A schematic flowsheet
for the process is presented in Figure 12.
Oxidation of materials such as copper acetate, malathion, and
tn'chloroethane were achieved on e laboratory scale at temperatures cf
3000C and reaction times of one, three and five hours respectively.
Copper bromide oroduced by bromination of copper acetate can be recovered
as copper sulfate for reuse by reactions of sulfuric acid. Reaction with
sulfiric acid evolves HBr, which is recycled. Oxidation of malathion
forms sulfuric and phosphoric acid, which can be precipitated from the
electrolysis liquor with lime.
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CC-f (TO AT
Figure 1?^ Flowsheet for Bromination Process for Destruction of
Hazardous Organic Materials
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Sodium Reduction Process
A sodium reduction process was being developed under contract by the
EPA for the destruction of halogenated organic materials and other
substances that undergo reduction reactions with elemental sodium to
produce nonnazardous end products. Elemental sodium reacts with
chlorinated hydrocarbons, for example, to produce sodium chloride, carbon
(graphitic) a,id hydrogen. The liquid sodium metal system is designed
along the lines of current heat transfer equipment and uses technology
derived from inert gas cleaning equipment. The carbon is filtered from
the moltan sodium and collects in a "cold trap" along with inorganic
salts. The hydrogen is flared. Destruction is complete to limits of
detection of waste (2-chloro-4-phenyl phenol, Kepone, sodium
fluorosilicate, antimony trisulfide).
BIOCHEMICAL DESTRUCTION
The feasibility of using selected pure cultures of microorganisms is
under investigation for use in degrading spilled hazardous material
residuals.(75; Certain organisms are known to be effective for
metabolizing normally biorefractory substances; nowever, practical use of
such organisms depends on their ability to survive in the presence of
indigenous bacteria. Pentachlorophenol, hexachloropentadiene, and methyl
parathion were successfully degraded in laboratory screening tests.
Greater than 90% removal of pentachlorophenol was achieved in a continuous
pilot scale unit operated at 2 liters per hour with c residence time of
48 hours and populated either with a bacterium or a fungus. Through
control of operating parameters, growth of indigenous bacteria that may
consume contaminant-degrading species is minimized.
MICROWAVE DECOMPOSITON
A microwave decomposition process for the decomposition of organic
wastes and pesticides has been reported by the Lockheed Palo Alto
Laboratories and the Solid and Hazardous Waste Research Division of the
U.S. EPA in Cincinnati, Ohio.(76) The microwave system consists of a
reactor through which the waste passes. Microwaves energy is applied to
the reactor and forms a plasma or ionized gas that breaks down the waste
by ion and electron impost reactions. Recovery of byproducts was
emphasized in the work. For example, phenylrrecuric acetate was decomposed
to water plus carbon dioxide and carbon monoxide, with the mercury
recovered in the metallic form. Methyl bromide and polychlorobiphenyls
have also been decomposed in the same system. The process handles a
kilogram per hour presently but may be scaled up to about 50 kg/hour.
Wet-air oxidation of hazardous organic materials is another possible
process for rendering these substances in nonhazardous forms. This
process is being investigated for treatment of hazardous industrial wastes
through the Hazardous Waste Research Division of the EPA in Cincinnati,
Ohio.
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ADVANCED FIXATION METHODS
The disposal of toxic heavy metals such as cadmium and arsenic can
present long-term storage problems. These toxic substances—being
elements—cannot be chemically decomposed; alternative processes such as
fixation in a form that exhibits very low Teachability must be used.
Incorporation of these substances in a suitable glass is one possibility
currently being explored by tne EPA. Borosilicate glass is one of the
leading candidate processes for fixation cf high level radioactive
wastes. Glass has the advantage of being a very inclusive material and
many elements of the periodic table can be incorporated in glass as
network formers or modifiers even though these elements are not glass
formers by themselves. A typical borosilicate glass used for high level
waste fixation will contain 20 to 35% of waste oxides and the leach rate
will be in the range of 10-4 to 10-7g/cn2 per day. Soluble
constituents such as cesium will exhibit a high leach rate whereas
insoluble constituents such as cerium nay have a leach rate that is 2 to 3
orders of magnitude less.(78) The leach rate of a high quality glass
will generally be several orders of magnitude less than that of a low
temperature fixation product such as in asphalt mix.
One problem with glassification methods is to ensure that the
hazardous waste is uniformly dispersed as very fine particles throughout
the glassy matrix. In an effort to reduce clumping of the waste, a
mixture of finely powdered glass anJ inorganic waste was thoroughly mixed
with a "Thermite"-!ike material anc1 the resulting powder was compacted
into a billet. Upon ignition, the mass fused into a dense frit that had
very low Teachability characteristics. Unfortunately, the hot billet
released some hazardous inorganics as vapors during melting, an aspect
that is undesirable since a chamber must be placed around the billet
during fusion and then the enclosure must be subsequently cleaned.(75A)
APPLICATION OF rjQVFL DISPOSAL TECHNIQUES
Need for New nisposal Methods
Evaluation of conventional disposal methods for spilled hazardous
material residuals has revea.'-d the need for additional methods to fill
the gap where conventional methods are either inadequate, uneconomical, or
frequently unavailable. One such gap involves destruction of chlorinated
hydrocarbons. Tne availability of a suitable incinerator for particularly
persistarit and hazardous matarials such as PCB's can be a problem in many
areas of the United States. Of particular concern is the disposal of
small quantities of highly J;oxic persistant materials.
The disposal of mixtures of hazardous spill residuals with extraneous
matter represents another jf the major problems with respect to extremely
toxic and persistant substances. Conventional disposal methods may not be
readily adapted to these materials. Disposal in a secure landfill does
not provide adequate long-term protection for the highly toxic peristant
materials. Therefore, efforts should be focused on substituting other
methods that do provide che protection desired. The EPA is currently
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considering various techt.iques for extracting or leaching the spill
residuals from mixtures with extraneous matter (such as soil or sediments)
in order to more readily convert the residuals to forms more suitable for
ultimate disposal.
yodified Evaluation Matrix
An evaluation matrix incorporating novel disposal methods was
prepared to determine the potential for achieving adequate environmental
protection with the use of these methods. The basic change includec in
the modified matrix is elimination of the secured landfill as an ultimate
disposal method (see Table 4). The objectives of the modified disposal
approach is: 1) to decompose all hazardous organic spill residuals to
innocuous end products and 2) to apply effective fixation processes to
materials containing hazardous heavy metals to ensure permanent
encapsulation of the metals under normal environmental conditions (e.g.,
burial in soil).
Biological and chemical treatment remains the first choice for
reactive organics and this can be accomplished with conventional
techniques. Unreactive and high hazard persistant organics show
incineration as a first choice, but novel chemical and biochemical
treatment methods will be available as options where a suitable
incinerator is not available. The effectiveness of leaching techniques
must be demonstrated in the case of mixtures with large quantitites of
inert matter.
New technology cannot dispose of toxic inorganic materials; the toxic
metals (ions) are elements and are not transmutable. Those materials that
are toxic in all forms will remain a major disposal problem. Secured
landfilling stands as the only option for these materials unless fixation
processes are sufficiently effective to produce a nonharzardous residue
that can go through normal disposal channels. In passing, one should
recognize that in some cases toxicity resides in an element or its ions
(Hg, As+35 C04 -2), in others the toxicity results from the
structure of the chemical (PBC, HCN) where the elements can be rearranged
into compounds that are generally not toxic (N?, C02, NaCl). A few
suostances (phenyl mercuric acetate) have structural and elemental
toxicity.
Based on the above considerations, future work must focus .on three
areas:
1) Economic alternatives to high temperature incineration;
2) Recovery or insolubilization techniques to remove the need for secure
landfills; and
3) means of concentrating hazardous constituents from large volumes of
inert substrates.
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TABLE 4 AMENDED MATRIX FOR NOVEL DISPOSAL METHODS
Hazardous
Composition Hazardous Organic Waste Inorganic Waste
Reactive Unreactive
Mixture with
minor amounts of
extraneous matter
Mixture .-.ith
substantial
amount of water
Mixtures ^ith
combustible
solids
Mixtures with
small non-
ccmhustible solids
B
0
A-B
A-0
L*-E
0
L*-3
L*-S
0
s
A-0
A-B
0
L-B
L-0
L-B
Highly Toxic/ Highly Toxic/
Persistent* Reactive Persistent*
0
S
A-0
A-B
0
L-0
L-B
B F-S**
B A-F-S**
B F-F-S**
B L-F-S**
+ See Appendix A for listing
* = optional
**= not required if fixeo product no longer meets hazardous waste criteria
B = Treatment (chemical or biochemical)
0 - Incinerate
F = Fixation
A = Concentrate and remove from water
L = Leach
S = Secured landfi11
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SECTION 8
IMPACT OF REGULATIONS FROM RESOURCE CONSERVATION AND RECOVERY ACT
Many residual materials associated with the clean-up of hazardous
material spills will by definition constitute hazardous wastes. While in
the past this has suggested that certain legal constraints existed to
prevent contamination of water and air through direct discharge, no
regulations addressed these materials specifically, and little or no
language addressee the use of land as a repository. Consequently, the bulk
of these wastes (spill residuals included) were disposed of on the land—
often indiscriminately. This option is no longer readily available. With
passage of the Resource Conservation and Recovery Act (PL 94-580) and
especially Title C of that Act, there is now a section of Federal law
mandating the promulgation of rules, guidelines, and standards regulating
the management of hazardous wastes. The implications of Title C are
therefore of direct importance to spill residuals management and warrant a
review.
Title C addresses hazardous waste management as one of the primary
objectives of RCRA. It directs the EPA to identify which wastes are
hazardous; the quantities, qualities, and concentrations of the wastes that
are hazardous; and the forms of disposal that pose a threat to public
health. Standards must also be issued for generators and transporters of
hazardous wastes. These include record-keeping practices, labeling,
selection of appropriate containers, use of a manifest system, and
reporting of quantities and disposition. Coordination is required to
ensure compatibility with transportation regulations (DOT, CFR Title 49).
Most importantly, persons owning or operating facilities for the
treatment and storage of hazardous wastes are required to obtain permits
within 90 days after identification and listing. Permit applications must
indicate composition, quantities, the rate at which such wastes are to be
disposed of, and the location of the disposal site. Permits can be revoked
for noncompliance.
The Administrator must also publish guidelines to enable the states to
develop approved hazardous waste programs. States with existing programs
may receive interim (two-year) authorization to show that their programs
are substantially equivalent to the Federal program. If non-conformities
resurface, authorization can be withdrawn. To facilitate enforcement, the
EPA and state officials are authorized to inspect facilities, ropy records,
and obtain samples as required.
While detailed guidelines and provisions have yet to be promulgated,
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'jroposed guidelines and regulations have been published in the Federal
Register, Volume 43, No. 243, Monday, December 18, 1978. The impact of
these regulations on spill residuals management must be considered. In the
event of a spill and subsequent response activity, management of residuals
will now require much greater attention to details. Only certified
disposal contractors can be used. Residuals will have to be properly
categorized and labeled. Manifest forms must be completed and submitted.
In most cases, prior permission will also be required before residuals can
be shipped to the disposal site. This will generally be the case, since as
a "one-time" waste, the residuals will not have been listed in the permit
application of the final permit granted to the site operator. In some of
the states that have already initiated their own version of Title C (e.g.,
California, Minnesota) there are emergency variance provisions that can be
invoked to bypass some of these time-consuming requirements and otherwise
expedite movement of residuals to an acceptable sice. It is entirely
possible that, in a trade-off between immediate safety considerations and
proper management, some residuals will still receive quick burial on-site;
but these will be infrequent occurrences.
As noted, the specifics of requirments have not been finalized as this
report is being prepared and may differ somewhat among states. Indeed,
several states have proposed more restrictive definitions than those
recommended by the EPA. It is therefore not possible to detail the
required course of action for handling spill residuals from any give7!
occurrences. Rather, response personnel must note that: 1) there will be
regulatory requirements, both Federal and state, and ?) only certified or
permitted contractors should be considered. Cognizance ot these factors
should stimulate proper inquiries at the time that disposal is
contemplated. Since the Federal program is in the formation stages, no
rosters are currently available to identify permitted disposal operators.
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REFERENCES
1. Environmental Protection Agency. 1976. "PCB Containing Wastes
Disposal Procedure," Federal Register, p. 1413o, April 1, 1976.
X. Environmental Protection Agency. 1975. "Hazardous Substance,"
Federal Register, Vol. 40, No. 250, Paper 59970-6.
3. U.S. Coast Guard. 1974. "CHRIS Hazardous Chemical Data," Report
No. CG-446-2, pp. 9-1 to 9-6, Washington, D.C.
4. Lawless, E. W., T. I. Ferguson, and A. F. Meiners. "Guidelines for
Disposal of Small Quantities of Unused Pesticides," Midwest Research
Institute, Report No. EPA-670/2-75-057, pp. 161-167.
5. Environmental Protection Agency. 1978. "Proposed Regulations fcr
Disposal of Hazardous Wastes," Federal Register, Volume 43, No. 243,
December 18, 1978.
6. "0)1 Spills and Spills of Hazardous Substances," U.S. Environmental
Protection Agency Publication, Oil and Hazardous Materials Control
Division, Office of Water Program Operations, Washington, D.C., 1975.
7. department of Transportation, United States Coast Guard. "Polluting
Incidents in and Around U.S. Waters; Calenaary Year 1973," U.S.
Government Printing Office, Washinqto, DC, 1974.
8. Wilder, 1. and J. Lafornara. 1972. "Control of Hazardous Material
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10. Schmiot, 0. J. I9b3. "Developments in Activated Sludge Practice,"
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Ref-1
7)
-------
13. Eo.enfelder, W. w. 1966. "Theory of Design," in Activated Sludge
Process in Sewage Treatment, Theory and Application Seminar,
University of Micnigari, Arm Arbor.
14. Hazeltine, T. R. 195b. "A Rational Approach to the Design of
Activated Sludge Plants," Biological Treatment of Sewage and
Industrial Wastes, Vol. I, Reinhold Pub'iishina Co., New York.
15. Sawyer, C. N. 1965. "Milestones in the Development of the Activated
Sludge Process," J. Water Pollution Control Federation, 37_(2).
16. KcKinney, R. E., and R. J. Ooten. 1969. "Concepts of Complete
Mixing Activated Sludge," Transactions 19tn Annual Conference on
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17- Sewage Treatment PI ant Design, Manual of Practice No. 8, Water
Pollution Control Federation, Washington, DC, 1959 (fifth printing,
1972).
18. Wing, B. A., and W. M. Steirifeldt. 1970. "A Comparison of Stone
Packed and Plastic Packed Trickling Filers," J. hater Pol hition
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19. BaUkrishnan, S., et al. 1969. "Organics Removal by Selected
Trickling Filter Media," J. Water and Wastes Engineering, 6jl).
20. McKinney, R. E. 1971. "Waste Treatment Lagoons—State-of-the-Art,"
Environmental Protection Agency, Washington, O.C., FPA Water
Pollution Control Research Series No. 17090 EHA 07/71.
21. Eckenfelder, W. W. 1970. Water Quality Engineering for Practicing
Engineers, Barnes & Noble.
22. Spyridakis, D. E. and E. B. .-.elder. 1976. "Treatment Processes and
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Publishers, Ann Aroor, Michigan.
23. Stewart, B. A. and L. R. Weber. 1°26. "Consideration of Soils for
Accepting Wastes," Land Application of Waste Materials, Soil
Conservation Society of America, Ankeny, Iowa.
24. Wallace, A. T. I97b. "Land Disposal of Liquid Industrial Wastes,"
Land Treatment and Disposal of Municipal anj Industrial Wastewater,
R. L. Sands and T. Asano, Editors, pp. 1-16, Ann Arbor Science
Publishers, Ann Arbor, Michigan.
Ref-2
72
-------
2b. Snyder, H. J., Jr. 1976. "Disposal of Waste Oil Re-Refining
Residues by Land Farming," Proceedings of a Research Symposium neld
at trie University of Arizona, February 2-4, 1976 en Residual
Management by Land Disposal, EPA-600/9-71-015, pp. 195-105.
2o. Benjes, H. J., Jr. 1977. "Small Community Wastewater Treatment
Facilities--Biological Treatment Systems." EPA Technology Transfer,
National Seminar on Small Wastewater Treatment System.
27. Heukelekian, H. and V. C. Rand. 1955. "Biochemical Oxygen Demand of
Pure Organic Compouncs." Sewage ano Industrial Wastes, 27(9):1040.
28. Ludzak, F. J. and M. B. Ettinqer. 1960. "Chemical Structures
Resistant to Aerobic Biochemical Stabilization. J. Water Poll.
Control Fed., 32jll):1172.
29. Scurlock, A. C., A. '„. Lindsey, T. Fields, and 0. R. Huber. 1975.
"Incineration in Hazardous Waste Management," EPA/530/SW-141, U.S.
Environment)! Protection Agency, 103 pp.
30. Yosim, S. u., L. F. brantham and D. A. Huber. 1973. U.S. Patent
3,778,320.
31. Yosim, S. J., 0. F. N'ckerizie, L. F. Grantham, and J. R. Birks.
1974. U.S. Patent 3,£45,190.
32. Miller, S. S. 1975. "How Hot is Ocean Incineration?" Environmental
Science and Tech-iology. _9(5):412-413.
33. Ricci, L. J. 1976. "Offshore Incineration Gets United U.S.
Backing." Chemical Engineering. 83(1):86-88.
34. Kianq, Y. 1976. "Licuid Waste Disposal System." Chemical
Engineering Progress. 83(1):71-77.
35. TRW Systems Group, "Recommended Methods or Reduction, Neutralization,
Recovery, or Disposal of Hazardous Waste," Report NO.
21485-6013-RU-OO, U.S. Environmental Protection Agency, 16 Voluir.es.
36. Ackerman, D., et al. 1977. "Destroying Chemical Wastes in
Commercial Scale Incinerators." EPA-o8-01-29o6, for the
Environmental Protection Agency, 173 p.
37. riemsath, K. H., and T. J. Schultz. 1977. "Application of Advanced
Combustion Technology for the Disposal of Toxic Waste," Paper
presented at Western States Combustion Institute Spring Meeting,
Seattle, WA, 29 p.
Ref-3
73
-------
38. Anonymous. 1976. "PCB-Containing Wastes--Recominended Procedures for
Disposal,11 Federal Register, 4JJ64): 14134-14136.
39. Whitmore, F. C. 1976. "Destruction of Polychlorinated Biphenyls, in
Sewage Sludge During Incineration/' EPA-68-01-1587, for the U.S.
Environmental Protection Agency, 80 p.
40. Anonymous. 1977. "Molten Salt Decomposes Pesticide Wastes,"
Chemical and Engineering News. b_5(37);44.
41. Shen, T. T., M. Shen and J. Lauber. "Incineration of Toxic Chemical
Wastes," Pollution rn-]ineering, p. 45, October 1978.
42. Philipbar, W. B., and J. T. Lurcott. "Incineration: the Best
Solution to Some Problems," Paper presented at the National Meeting
of the American Chemical Society, Honolulu, Hawaii, April 1-6, 1979.
43. Hubregtse, K. R., et al. 1976. "Users Manual for Control and
Treatment of Hazardous Spills." Final Report to EPA from Rexnard Co.
44. TWR Systems Group. 1973. "Recommended Methods of Reduction,
Neutralization, Recovery or Disposal of Hazardous Waste."
Volumes XII and XIII. hnvironmental Protection Technology Series,
EPA-670/2-73-G53-1.
45. Pi lie, R. J. et al. 1975. "Methods to Treat Control and Monitor
Spilled Hazardous Materials," environmental Protection Technology
Series, EPA-67U/2-75-042.
4t>. Donnent, E. H. 1978. "Precipitation, Flocculation, and
Sedimentation," Unit Operations for Treatment of Hazardous Industrial
Wastes, D. J. DeRenzo (ed.). Hoyer Data Corporation, Park Ridge,
New Jersey, pp. 502-534.
47. Battelle Memorial Institute. 1968. "A State-of-the-Art Review of
the Metal Finishing Industry," Environmental Protection
Agency 12010 EIE.
48. Skripach, T., V. K.^gan, M. Komanov et al. 1971. "Removal of
Fluoride arid Arsenic from Wastewater of the Rare Earth Industry,"
Proc. 5th International Conference Water Pollution Research,
2:111-34, Pergamon Press, New York.
49. Program for the Management of Hazardous Water for the Environmental
Protection Agency, Office of Solid Waste Management Programs; Final
Report, Battelle Memorial Institute, Richlano, WA, July 1973.
Ref-4
74
-------
50. Howe, R. H. iyo3. Recent Advance in Cyanide Waste Reduction
Practice. Purdue Industrial Waste Conference, pp. 690-705.
51. feattelle Memorial Institute. An Investigation of Techniques for
Removal of Cyanide from Electroplating Wastes. Enviromental
Protection Agency, 12010 FIE.
52. Che.-emisinoff, P. N. and W. F. Holcomo. 1976. Management of
Hazardous ana Toxic Wastes. Poll. Eng., pp. 24-32.
53. Conner, J. R. 197t>. "Chemical Fixation of Hazardous Spill
Residues." In Proc. 1976 Nat. Conf on Control of Hazard. Mat.
Spills, pp. 416-423.
54. Kleiman, G. 1975. "A Practical Approach to Handling Flue Gas
Scrubber Sludge." Paper presented before the 37th Annual Meeting of
the American Power Conference, Cnicago, IL.
55. Anonymous. "The Stabilization Game." Envir. Sci. Tech. 9, No. 7,
pp. 622-623.
56. Maloch, J. L. "Leacnability and Physical Properties of Chemically
Stabilized Hazardous Wastes." EPA-600/9-76-015, U.S. Envir.
Protection Agency, Cincinnati, Ohio, pp. 127-138.
57. Wiles, C. C. and H. R. Labowitz. 1976. "A Polymeric Cementing and
Encapsulating Process for Managing Hazardous Waste."
EPA-600-9/76-015, U.S. Environ. Protect. Agency, Cincinnati, Ohio,
pp. 139-150.
ba. Ames, L. L., Jr. I960. Some Cation Suostitutions During the
Formation of Phosphorite from Calcite. Econ. Geol., 55, pp. 354-362.
59. Christensen, D. C. and W. Wakamiya. "A Solid Future for
Solidification/Fixation Processes," Paper presented :t the 177th
National Meeting of the American Chemical Society, Honolulu,
April 1-6, 1979.
60. Perket, C. "An Assessment of Hazardous Waste Disposal in Landfills:
State-of-the-Art,-' Proceedings of the National Conference on Control
of Hazardous Material Spills" Miami Beach, Florida, April 11-13, 1978.
61. Liptak, B. &. 1974. Environmental Engineers handbook. ChiHo Book
Co., Radnor, PA.
62. Field, T. Jr. and A. W. Lindsey. 1975. "Landfill Disposal of
Hazardous Wastes: A Review of Literature and Known Approaches."
EPA/530/SW-165, U.S. Environ. Protection Agency, Washington, DC.
Ref-5
75
-------
63. Lindsey, A. w. "Ultimate Disposal of Spilled Hazardous Materials,
Chem. Eng., October 27, 1975.
64. Pavoni, J. L., 0. J. Hagerty, ana p. E. Lee. "State-of-the-Art of
Land Disposal of Hazardous Wastes," paper presented at the Seventh
American Waste Resources Conference, Washington, D.C., October 24-28
1971.
6b. Andres, D. R. 1977. "Disposal System Swallow Cyanide," Waste Aqe,
pp. 65-68. "-
66. Straus, M. A. 1977. "Hazardous Waste Management Facilities in the
United States - 1977." Report No. EPA/539/SW-146.3.
67. David, K. E. aiid R. J. Funk. 1974. "Subsurface Disposal of
Industrial Wastes," Industrial Water Engineering, 11(16).
68. Tofflemine, T. J. and u. P. Brezner. 1971. "Deep-Well Injection of
Wastewater," J. Water Pollution Control Fed., 43(1473).
69. Warner, D. L. "Subsurface Disposal of Liquid Industrial Wastes by
Deep-Well Injection," American Assoc. ot Petroleum Geologists Memoir,
No. 10, p. 16, 1968.
70. Walker, W. R. and R. C. Stewart. 1968. "Deep Well Dispcsal of
Waste," J. Sanitary Eng. Div., Proc. American Soc. Civil Engr.,
y£( 94 5). '
71. Environmental Protection Agency. 1973. "Ocean Dumping-Final
Regulation and Criteria, Federal Register, 33, No. 198.
72. Lehman, J. "Growth Potential for Hazardous Waste Management Service
Industry,"NSwMA Industrial Wastes Equipment and Technology
Exposition. Chicago, June 2, 19/6.
73. Black, M. W. and 0. Usher. "Safe Disposal of PCB's." Proceedings of
tne 1977 National Conference on Treatment and Disposal of Industrial
Wastewaters and Residues, Houston, TX, April 26-28, 1977.
74. Darnell, A. J. "Disposal of Spilled Hazardous Materials by the
Bromination Process," Proceedings of the 1978 National Conference on
Control of Hazardous Material Spills, Miami Beach, April 1978.
75. Thuma, N. K.., P. E. O'Neil, S. G. Brownlee and R. S. Valentine.
"Biodegradation of Spilled Hazardous Materials," Proceedings of the
1978 National Conference on Control of Hazardous Material Spills,
Miami Beach, April 1978.
75a. Greer, J.S., G.H. Griwatz, S.S. Gross, R.H. Hiltz. "Sodium Fluxing
and In-Situ Classification for Hazardous Spills, EPA-600/2-82-029,
U.S. Environmental Protection Agency, Cincinnati, Ohio, 1932, 27pp.
Ref-6
76
-------
76. fneremisinoff, P. N. and W. F. Hoi comb. 19/6. "Management of
Hazardous and Toxic Wastes," Pollution Engineering, pp. ^4-32.
77. Battelle, Pacific Northwest Laboratories. 1976. "Alternatives
Manaaing Wastes from Reactors and Post-Fission Product Operations in
the LWR Fuel Cycle," Report No. EPOA 76-43, Volune 2.
78. l-'.endel, J. E. 1973. "A Review of Leaching Test Methods and
teachability of Various Solid Meaia Containing Radioactive Water," US
AEC Report No. BNV.t-1765.
Ref-7
77'
-------
Columns 1-3
X
(blank)
NR
Column 4
C
I
R
T
X
APPENDIX A
SYMBOLS
Aff irmative
Negative
No information available
Potentially hazardous due to corrosivity
Potentially hazardous due to ignitabi1ity
Potentially hazardous due to reactivity
Potentially hazardous due to toxicity
Spill residues definea as hazardous in proposeu RCRA
regulations
C = pH <3 or 21?.
I Plash point <60«C (1400F)
ASTM D-93-72 Pensy Martin closed cup.
R - Reactive, e.g., reacts with water and other common suostances.
T - Toxic as As, Ba, etc.
A-l
73
-------
APPENDIX A
LIST OF HAZARDOUS MATERIALS AND TREATNtdT OPTIONS
Common Haute
ANTU
Acetaldehyds
Acetic Acid
Acetic inl.ydrMe
Acetone
Acetone cyanonydrln
Acotunltrite
Acetopiie'ione
Acetyl oroailde
Acetyl chloride
Acety'ene
Acrolain
f cry Me actd
Acrylonltrlle
Adlponltrlle
Alachlor
Aldtcarb
Aldrin
Ally) alcohol
Allyl chloride
Aluminum chloride
Aluminum fluoride
Aluminum sulfate
Ami noe th Jnol a .nine
Amenable to Conventions!
Biological Treatment
NR
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Amenable to Aqueous
Chemical Treatment
NR
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Highly
Amenable to Toxic and
Incineration Persistent
X
5!
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X X
X
X
k
RCRA
Defined
Hazardous
1
C
C
1
X
1
I
1
X
1
X
X
X
I
1
R
-------
AvpnnU
Coapounds
CO
CD
I
CO
acetate
Anaionlua benjoata
i blcirbonat*
bisulfite
brealda
carba.Trite
carbonate
cltloride
citrate; dibasic
Aranonlusa flcuborate
Amasoniua hydroxide
Asmoniua hypopliosphlte
An3743nlaa iodide
Asrnnniua nitrate
i oxalsle
pentaborats
porchlorate
pe'suUite
siliconuoride
sulfsoute
sulfate
sutHde
sulflte
tartrate
thlocyanate
Arayl acetate
Amy) alcohol
Aniline
Antlaony Compounds
Antl[A>ny pentachlortde
Antisxiny pentafluorlde
Antimony potasslus tartrate
Antiuwny tribrc&lds
Ainenable to Conventional
Biological Treatment
X
X
X
X
X
X
X
X
X
m
X
X
X
X
X
X
X
NR
X
X
X
X
X
X
X
X
X
Amenable to Aqueous
Cheated! Treftetnt
R
X
r«R
x
x
X
X
X
to
Inclnerativ...
Highly
Toxic and
Persistent
RCRA
Defined
Hazardous
-------
Coisaon
Antlgiony trichloride
Antliaony trifluarlda
Antloony trloxlde
Arsenic Cot^wunds, Inorganic
Arsenic acid
Arsenic dlsulflde
Arsenic pentaoxlde
Arsenic trlcliioride
Arsenic triaxlde
Arsenic trlsulftde
Calcluss arsenate
Potesslos) arsenate
Pctssslua arscnlte
Sadlua arssn^te
Sodtua fir-sen lie
Asphalt blending stocks
Roofers flux
Asphalt
Asphalt blending stocks
Straight run residue
Atrazlne
Bacillus thurSngus
Barlua carbonate
Benzaldehyde
Benzene
Benzole acid
Benzonltrlle
Benzoyl chloride
Benzyl chloride
Amenable to Conventional
Biological Treatment
NR
X
X
X
X
X
X
Amenable to Aqueous Amenable to
Cheatcal Treatment Incineration
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Hitjhly
Toxic and
Persistent
X
X
X
X
X
X
X
X
X
X
X
RCRA
tH fined
Hazardous
R
R
T
T
T
T
T
T
T
T
T
T
r
NR
X
NR
-------
Co
Compounds
i,. ,>! i;.,3 chloride
i'-.j,-;Hue fluoride
Ccryiltu: nitrate
SliphenoJ A
Butadiene, inhibited
Eutene
1,4-Btjtenediol
Butyl «celst*
r,-Butyl acrylata
fso-Butyl
n-3utyl
sac-Butyl alcohol
tert-Butyl alcoto)
Duty late
Butylene
tert-Butyl hydruperonlde
! ,4-Butyncdlol
n-ButyraUtehyd«
Iso-Butyraldeiiyde
Butyric acid
Bux
CDAA
Cacodyllc acid
Amenable to Conventional
Biological Traatsant
NR
NN
KR
NR
NR
X
X
X
X
X
X
X
NR
NR
NR
X
X
X
NR
NR
NR
Asenable to Aqueous
Chealcal Treatcant
£aen«ble to
X
X
X
ER
KB
X
MR
NR
W
NR
NR
HR
X
a
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
NR
X
X
X
HR
NR
X
Highly RCRA
Toxic and Defined
Persistent Hazardous
-------
teeneble to Conventional
Biological Treatment „
oo
Cadaiuo Compounds
acetate
Cadratusa b reside
Cadaluai chloride
Calolua carbide
Celclu* fluoride
Calclun hydroxide
Calclun hypochlorlte
talcluo os Ids
Caoiphor oil
Csptafol
Captan
Carbaryl
Carbofuran
Carbon dlsulflde
Carbon tetrachlorlde
Carbophenothlon
Chlorani-an
CMordane
Chlorine
Chlorobenzene
Chlorobenzllate
Chlorofora
Chlorohydrlns
Chloroplerln
Chloroprophaa (CIPC)
Chl&roculfnnlc acid
tffi
NR
X
NR
NR
NR
X
NR
X
NR
NR
NR
kmenebla to Aqueous
Cher, tea? Treatment
X
X
X
X
X
X
X
BR
X
NR
HP
NR
X
NR
NR
Wk
NR
X
Angnable to
Incineration
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Highly RCRA
Toxic and Defined
Persistent Hazardous.
NR
HP
X
NR
NR
NR
X
X
NR
NR
C
CR
X
X
X
X
X
R
X
X
X
-------
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-------
Kaise
CO
ChrcwtuM Compounds
Aranontua bichromate
Amnoniua chronate
Calciua chrffiMte
Cliroalc acetate
Chroaic «cld
Chrcxaic sulfate
Chroffious chloride
Chrcayl cillcrida
LUhiua bichromate
LUhiu!G chrosrate
Potasstea bichromate
Potassluia chrozate
Sodlti-!! bichrceite
Sodtusa chroisate
Strcncitca ctircoate
Zinc btchroevate
Cobalt Cospcunds
Cobattous broalde
Cobsltous fluoride
CcfcsHoys fore^te
Cobaito-js sulfasate
Copper
Cuprtc
Cuprlc
Cuprtc
Cuprlc
Cuprlc
Cuprlc
Cu-napl
Cupric
Cuprlc
Cuprlc
Cupric
Cuprlc
Cupric
Cuprous
to Convention*!
Biological Treatment
acetate
chloride
formate
glydi.ate
lectata
litt'.cnates
nUrete
oxalats
subacetate
sulfite
sulfate, asaaoouted
tartmte
brc-alde
Aasnable to Aquoous
Tretteant
AaenabJe to
Incineration
Hiyhly
Toxic and
Persistent
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
RCRA
Defined
Hazardous
-------
H-saa
CO
en
Corn syrup
COliMfilOS
Cresol
Creosote
Crotortaldehyde
Crufoaate
Cuaaivs
Cyanide Compounds
lEUrlua cyanide
Calclua cyanide
Hyirogsn cy^ntda
Potfisslua cyanide
Sodli..^ cyanide
Zinc cyanide
Cyanogen brcaide
Cyanogen chloride
Cyclohexsne
Cyclchexanone
Cyclohs»ylac;!ne
2.4-0 (acid)
2,4-D (esters)
08CP
DCPA
DEET
0£F
D«lapon
K)T
Decaldehyde
Amenable to Conventional
Biological Treat-lent
X
X
X
NR
NR
MR
NR
X
X
X
X
X
X
X
X
X
X
X
X
NH
m
Amenable to Aqueous
Chtslcal Treatment
X
X
X
X
«n
«a
x
x
X
X
X
X
X
X
NR
Assemble to
Incineration
X
X
X
X
X
X
X
X
X
X
Tsxlc and
persistent
X
X
X
X
X
X
X
X
*
Defined
Hazardous
X
I
X
1
X
X
X
X
X
X
X
X
1
I
I
X
X
X
MR
NR
NR
KR
KR
X
KR
NR
KR
HR
MR
X
-------
Coajson ftaae
J-deuifia
n-decyl alcohol
Dextrose solution
Oiacetorie alcohol
Dlszir.on
Dlbssuoyl peroxide
OtbutylphtlialetB
Oicaaba
Olchlotenll
iitchlona
Ptchlorvos
a-utchl oro benzene
p-d!ch!oroben:ena
Olchlcrodlfluoroscthane
Dlchiora-Mthanc
2,4-dichlorop!icno)
Olchloropropsne
Olchloropropcne
Olcofol
Otcyclopentadiene
Dleidrln
Olethanolanlne
Dlethylaaine
Diethylbeniene
Olethyl carbonate
Dlethylen* glycol
Aaenatle to Conventional
eioloq'.cal Treatment
NR
X
X
X
NR
X
NR
NA
HS
x HR
X
X
X
X
X
NR
HR
X
X
X
X
X
Aaenoble to Aqueous Asentblc to Toxic ai
Chsstcal TreaUent Incineration Persist
X
X
X
X X
X
?SS X
X
KR X
HR X WR
KR X Kft
X
X
X
X
X
X
X
NR X NR
X
X X
X
X
X
X
X
Highly RCRA
Defined
Hazardous
-------
Co
—I
I
»—J
(_J>
Ccsnson Haas
Dlethylene glycol
Konoethylothcr
Otethylene glycol
Bonossthyl ether
Oifrthylene glycol
dlnethyletticr
Diethytenetrtaalne
Dltsobutylcarbinol
Dltsobutylene
D«soprot>3noUaine
DJBsthoat'
OfaatfiyUtaintf
Blawthy) fonsaaide
1 ,t-dn«
OloethyUuKite
Olnethyl«i>)fax1de
Otnoseb
2,4-dinUrcanillne
Dlnttrobenzens
Olnttrcphenol
Dior'yladlpstj
OJactylphthaltte
1.4-dtoxcne
DIptierMJd
Dlphenyicathane
LM Isocycr.ate
Dlprcpylane glycol
Olquat
A«en£ble to Conventional
B1olo<)(c*l Treatment
X
X
X
X
X
Nft
X
MR
X
X
X
KR
NR
X
HR
NR
NR
HR
HR
N£
X
KR
tecnible to Aqueous
Cheoic«1 Treatment
NR
KR
NR
rat
KR
KS
NR
NR
t»
HR
Aaenible to
Incineration
X
X
X
X
X
X
X
X
X
X
X
X
• X
X
X
X
X
X
X
X
X
X
X
X
X
Toxic and Defined
Persistent Hazardous
KR X
I
1
X X
X
X
X
1
X
-------
Amenable to Conventional
CoozBon Naise Biological Treatment
Distillates: flashed
feed stocks
Distillates: straight run
CUolfoton
Dtthiocarbaeates
Diuron
Dodecene
1-dodecene
Oodecenol
Dodecylbsnzenesulfonlc acid
Dodecylbenzenesulfonic «ctd,
-alclua salt
Oodecyltenzsnesulfontc acid.
taopropanolatolne salt
Dodecylbenzsnesulfonk scla,
sedlua salt
CodecylbeRtenesulfonic acfi,
triethir.otsaine salt
Oodin'S
Cowthena
D-.irsban
DyfuoaU
EPTC
Endosulfan
tndotna1-
Endrln
Epichlorohyfrln
EpoxlJixed vegetable oils
X
X
NR
NR
NR
X
X
X
X
X
X
X
X
NR
NR
NR
NR
K'R
NR
NR
Amenable to Aqueous
Cheaical Treatment
C?.
HR
«R
NR
Hft
NR
HR
NR
NR
NR
Amenable to
Incineration
X
X
X
X
I
X
X
X
X
X
X
X
*
X
X
X
X
X
X
X
X
X
X
Toxic ai
Persist'
X
X
NR
NR
Nfl
NR
NR
X
Highly RCRA
Defined
Hazardous
-------
Highly RCRA
taenabie to Conventional Aaenable to Aqueous Aaentbte to Toxic and Defined
Coeraon Macs __ Biological Treatatiit Cheatct) Treitceot Incineration Persistent Hazardous
Ethane ^ I
Ethlon I!S X t!R X
Ethoxylated dodecanol X X
Ethenylated pentadecenol X X
Ethoay^ated tetradecanol X X
EthoxyUtvXl trldecano) X X
Ethaxy trlgtycol X X
Ethyl acetate X X
Ethyl scrylate X X
Ethyl alcohol X X
Ethylbeniene X X
Ethyl buUnol X X
Ethyl chloride x X
--, Ethylene
>-• Ethylene cyanohydrfn KS KM X R
ro
Ethylenedl&alne X XX I
Ethytenedlaalre, tetraacettc
ecld X x X
Ethylene dlbronttd NR X X
Ethylene dlchlorlde NR X '
Ethylene glycol Aonoethylether
acetate X X
Eihylene glycol dlnethylether X X
Ethylene glycol nonoethylether X X
Ethylene ylyccl X X
Ethylene glycol nonobutyl ether X X
Ethylena glycol «onoacthylether X X
Ethyleneimlne X X
-------
Ccanon Name
Ethylene oxide
Eihylether
Ethyl hexandiol
2-eth>Jl hexanol
Ethyl hexyl tallate
2-ethyl-3-propylacrole1n
Fenltrothion
Fensulfothlon
Ferrous sulfate
Fluasoturon
fluorine
Fluorine Confounds
Aluslr.^j fluoride
tesonlira blfluoride
fesnonluJi fluoride
Hydrofluoric acid
Sodiua bifluortde
Sodium fluoride
Stannous fluoride
Folex
Folpet
Formaldehyde
Fcrraic acid
Funartc acid
Furfural
Gas oil: cracked
teenable to Conventional
Biological Treat-event
A
NR
X
X
X
NFI
NH
NR
X
X
NR
NR
X
X
K
X
X
.'aenabte to Aqueous
Cheat-.*! Trpstaent
NR
NR
NR
X
NR
X
X
X
X
X
X
X
X
NR
NR
X
Anenable to Toxic and
Incineration Persistent
X
X X
X
X
X
X
X
X
X
X NR
X NR
X
X
X
X
X
Defined
Hazardous
1
1
X
X
X
X
1
Gasoline blending stocks:
slkylates
-------
Gasolines: autcoctive
(<4.23 g lesd/gal)
Gasolines: avUtion
(<4.86 s lead/gal)
Gasolines: casinghead
Gasolines: polymer
Gasoline blending
Stocks: refonsates
Glycerine
GlycidyloethacryUte
Guthicn
Meliotropin acetat
Heptochlcr
Heptena
1-heptcne
Hexjaethy 1 enedl aoi r.e
Eiexanol
1-hexena
Hexylcne glycol
Hydraz'ne
Hydrochloric *cid
Hydrogen peroxide
Hydrogen suiflde
Mydroxylaralnc'
Amenable to Conventional
Biological Treatment
X
X
X
X
MR
X
X
X
X
X
X
X
X
X
/taenable to Aqueous
Cheajcal Treataent
Alienable to
Incineration
Hi'jhly RCRA
Toxic and Defined
Persistent Hazardous
X
HR
X
X
X
X
X
X
X
X
X
X
X
\ X X
\X MR
s
? *
,\
«\
X •.
\
X ^
\
y V
* V
x' \
X
X
X
-------
Cnraon Kama
iron
ferric esxontua citrate
Ferric amonlua oxclate
Ferric chloride
Ferric fluoride
Ferric nitrate
Ferric sulfste
Ferrous in-jscniua sulfate
Ferrous chloride
Ferr'ui sulf«ta
to Conventlonil
Biological Treatment
Isoat^ylslcohol
Isobutane
Isabutylalcouol
Isobuiylene
IsodecaldehyJ"
Isodscylalcohol
Isohexane
Isocctatdehyde
Iscoctylalcohol
Isopentane
Isoprcne
Isopropylacetate
Jot fuels: JP-4
Jet fuels: JP-1 (kerosene)
Jet fuels: JP-3
Jet fuels: JP-5 (kerosene.
heavy)
Kerosene
Kerthane
Late,«,. liquid synthetic
X
X
X
X
X
X
X
X
X
X
X
Amenable to Aqueous
Chealol Treatasrt
Aosnable to
Incineration
Highly
Toxic and
Persistent
Rf.RA
Defined
Hazardous
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
-------
I
H-*
m
Conxion Name
Laurvl nercaptan
Lead Compounds
Lead acetate
Lead trsenate
lead ehlorlda
Lead fluotorate
Lea
-------
COKESOO tisas
Kercury Compounds
Ksrcuric *cetsta
Kercurtc cyanide
Mercuric nitrate
Marcurlc sulf«te
t&rcurtc thiocyanate
Harcurous nitrate
Amenable to Conventional
Biological Treatment.
Kethane
Kathanearsonlc tcld
Sodiua Salts
Katho^yl
Hat'ioxychlor
Itsthyl acrylate
Kethyl alcohol
Methyl £qyl acetate
Kathyl aayl alcohol
Kethyl broaide
Kethyl chloride
Kfithylethylketone
fethyluthylpyrldlns
Kethy UsoLutyicsrbtnol
Hethyl IsobutyUetoae
ftethyl ceercaptan
Kethyl Betliacrylate
pa rath ton
HR
HR
NR
Mineral spirits
tble to Aqueous
steal Treatment
X
X
X
X
X
X
Na
HR
Nft
MR
taenable to
Incineration
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Highly RCRA
Toxic and Defined
Persistent Hazardous
T
X T
X I
X T
X T
X T
X T
m i
I
X T
T
NR X
X
I
1
1
1
X
1
I
1
I
1
I
X
X
1
-------
CO.TSB/I Hams
Amenable to Conventional
Biologic*! Treatment
Honocrotophos
Honoethartol aai ne
Honoethylagilne
Honolscpropanolanlne
KostcissthyUatne
Horphollne
Naptslaa
Kaphths: coal Ur
Naphthalene
Kophtha: solvent
N^phtha: stoddard solvent
Niphthi: «4 I f (7SS naphtha)
Haphthenlc acid
Nickel Compounds
Nickel sicrajitua sulfate
Nickel chloride
Nickel foreute
Nickel hydroxide
Nickel nitrate
Nickel sulfate
nicotine
Nttralln
Nitric acid
Nitrobenzene
NUrogen dioxide
Nltrometho,.e
.'(Urophenol
NR
X
X
X
X
X
KR
X
X
X
X
X
X
NR
X
X
Amenable to Aqueous
Chealca! Trsitsent
KR
X
X
X
X
NR
X
X
X
X
X
X
X
KR
KR
X
Anenabl* to
Incineration
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Highly RCPA
Toxic and Defined
Persistent Hazardous
X NR
X NR
X HR
-------
Cotroor! Nac*
I
Nltrosylchlorlde
Monattol
Honene
1-iwneae
Konylphenol
Norbomlde
Korea
Octanol
'-octsne
Oils: clarified
Oils: etude'
Oils: diesei
Oils, edlblri: castor
;
Oils, edible: cottonseed
Oils, edlbie: fish
01 is, edHle: olive
Oils, ediole: peanut
Oils, edible: soyabean
Oils, enible: vegetabij
Oils, fuel: no.
Amenable to Conventional Amenable to Aqueous.
Biological Treatment Chemical Treatment
Oils, /uet:
Oils, fuel:
01 u, fuel:
Oils, fuel
Oils, fuel
Oils, Fuel
Oils, Miscellaneous:
absorption
(kerosene)
no. 1-0
no. 2
no. 2-D
no. 4
no. 5
no. 6
KR
X
X
X
X
KR
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
NR
NR
NR
Highly
Ataenable to Toxic and
Incineration Persistent
NR
X
X
X
X
X NR
X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
RCRA
Defined
Hazardous
1
1
1
!
1
I
I
I
i
-------
COBROII Name
ro
O
Oils, miscellaneous: coal tar
Oils, miscellaneous:
lubricating
Oils, miscellaneous:
mineral
Otis, miscellaneous:
mineral seal
Oils, miscellaneous, motor
Oils, miscellaneous:
• neatsfoot
Oils, miscellaneous.
penetrating
Oils. cslscellaneous:
Oils, eslicellaneous:
Oils, miscellaneous:
Oils, miscellaneous:
Oils, miscellaneous:
Oils, miscellaneous:
Oils, miscellaneous:
Oils, nfscellaneous:
Oils, miscellaneous:
Oils, miscellaneous:
trans fontsir
Amenable to Conventional
Biological Treatment
X
X
Amenable to Aqueous
Chemical Treatment
l'; acid
PCN3
Parafonsaldenyde
Paraquat
Pa rath Ion
Pentachiorophenol
range
resin
road
rosin
spera
spindle
spray
tall
tanner's
X
X
X
X
X
y
X
X
X
X
X
HR
X
NR
X
X
NR
NR
Amenable to
Incineration
X
X
X
X
X
X
X
X
X
X
X
X
X
X
NR
X
X.
X
X
Highly
Toxic and
Persistent
RCRA
Defined
Hazardous
I
X
NR
NR
X
-------
Highly RCRA
Amenable to Conventional Amenable to Aqueous Amenable to Toxic and Defined
Coaaion Name Bloioiieal Treatggnt_ Chemical Treabrent Incineration Persistent Hazardous
Pentadecaitol _ X X
Pentane X I
1-pentena X I
Petrol atua X X
Petroleum naphtha • X I
Phenol X X
Phorate KH KR X NR X
Phosgene X
Phosphoric acid X C
Phosphorus MR KR R
Phosphorus oxychlorlde NR NR R
Phosphorus pentasulflde NR NR R
r'0 Phosphorus trichloride NR NR R
" Phthallc anhydride X X
Plcloraa NR X NR
Plndone MR KR XXX
PtpBronyl butoxlde NR HR X
Polyacrylonltrlle X
Polychlorlnated blphenyls. XXX
Polyiiedrlvli-us NR NR - X
Polyphosphorlc acid X
Polypropylena glycol X X
Kathylether X
Pot»stus hydroxida X C
Potasslua Iodide X
Potasjlus) por-oangiinsta X R
Propachlor NR NR X Nit
-------
Cccsnon Name
ro
ro
Propane
Propanll
Propazlne
Proplenaldehyde
Proplonic ecld
Propicnlc
Propyl alcohol
Propylene
Propylene butylene polycer
Propylcne glycol
Propylene glycol ;na thy lather
Propylene oxide
Pyrethrlne
Pyrldlne
Qulnotlne
Resorclnol
Ronnal
Ro tenor. 2
Selenium oxide
Silver nitrate
Sllvex
Sodiua
Scdtusi aldyl bsnienesul fonates
Benzenesul for.ates
SoJIura aUylsulfates
Amenable to Conventional
Biological Treatment
NR
KR
X
X
X
X
HR
NR
NR
NR
NR
AiRsnable to Aqueous
Chealcal Treatnent
Aneneble to
incineration
Highly RCRA
Toxtc and Defined
Persistent Hazardous
I
HR
NR
X
X
NR
NR
X
X
NR
KX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
NR
X
X
X
HR
NR
I
I
1
I
I
X
1
X X
X X
T
T
R R
NR
-------
Conrnon Name
o
O
Sod1us amide
Sodium bisulfite
Sod!un borohydrlda
Sodlua chlorate
Sodiua ferrocyanide
Sodlua fluoracetate
Sodtuo hydride
Sodlua hydrosulflde
Sodlura hydroxide
Sodtun hypoch'.ortte
Sodium ntethyUte
Sodium nitrite
Sodlun phosphate, dibasic
Sodium phosphate, aonobaslc
Sodium phosphate, tribastc
Sodiua selenitc
Sodtun sillc.te
Sodium sulfide
Sodium sulfite
Sorbitol
Strychnine
Styrene
Sulfolana
Sulfur (l<(|uld)
Sulfur dioxide
Sulfuric acid
Sulfur Ewnochlorlde
Amenable to Conventional
Biological Treatrent
NR
NR
X
HR
X
NR
Hi{!hiy
Aa«nable to Aqueous Auenable to Toxic
-------
Coamon Name
Sulfurylchloride
2,4.5-T (acid)
2.4.5-T (esters)
TBA
TCP and salts
TOE
Tallow
Tetrachloroethy'. ene
Tetradecstiol
1-tetradecene
Tetraethyl lead
Tetraethyl pyrophosphate
o '" Tetrahydrofuran
4:1 Tetrahydronaphthalene
Tetranethyl lead
Titanium tetrachloride
Toluene
Toluene 2.4-dlssocyanate
Toxaphene
Trichlorfon
Trlchloroethane
Trichloroethylene
Trlchlorofluoroce thane
TrlcMorophenol
Trlcresyi phosphate
Tridecanol
Amenable to Conventional
Biological Trea tisane
NR
NR
X
X
X
X
NR
NR
HR
NR
NR
X
Amenable to Aqueous
Chemical Treatment
X
NR
NR
X
X
X
KR
HR
NR
HR
NR
Highly
Amenable to Toxic and
Incineration Persistent
X
X X
X X
X X
X X
X
X
X
X
X X
X
X
X
X X
X
X
X X
X
X
X
X
X X
X
X
RCRA
Defined
Hazardous
R
T
T
X
X
X
X
1
R
I
r
X
X
X
X
X
X
-------
o
ISO
Cojrmon Nane
1-trldecene
TrtethanoU^lne
Trlethylasilne
Trlethylbenzene
Trlethylens glycol
Trie thy lenetetrasilne
Trlfiuralin
Trlssedlure
TrleKthylaiclne
Turpentine
Undecanol
1-undecene
Uranlua Ccopounds
Uranium peroxide
Urany] acetate
Uranyl nitrate
Uranyl sulfate
Amenable to Conventional
Biological Treatrent
X
X
X
X
X
X
ttt
NR
X
X
X
X
Amenable to Aqueous
Chemical Treatment
X
NR
NR
X
X
X
X
Amenable to
Incineration
X
X
X
X
X
X
X
X
X
X
X
X
Toxic >
Persls
NR
X
Highly RCRA
Defined
Hazardous
Urea
Valeraldchyds
VanadUni Cos\j>ounds
Vensdlua pentoslda
Vanadyl sulfete
Vernoiate
Vinyl acetate
Vinyl chloride
VinylIdenechlorlde Inhibited
Vinyl toluene
Warfarin
NR
X
NR
HR
KR
KR
HR
H-
KR
KR
-------
o
Co
Kataa
Waxes: cenvaubj
Waxes: paraffin
XylerM .
Xylenol
Zectrsn
Zinc Compounds
Zinc acetate
Zinc assoniusi chloride
Zinc borate
Zinc brealda
Zinc carbonate
Zinc chloride
line fluoride
Zinc forsate
Zinc hydrosulfite
Zinc nitrate
Zinc phanolsulfonate
Zinc phosphide
Zinc potassiioi chrosste
Zinc sUtcofluortde
Zinc sulfa'.a
Zinc suUfite, eonohydrate
Zlrcontuta Compounds
Zirconlua acetate
Zirconim potasslua fluoride
Zirconiua nitrate
Zirci-niwB oxychloride
Zirconiua sulfate
Zircontua tetrachlortdc
to Conventional
Biological Treatment
Amenable to Aqueous
Chaaical Treatment
taenable to
incineration
X
X
X
X
X
Highly
Toxic and
Persistent
RCRA
Defined
Hazardous
-------
APPENDIX B
DESCRIPTION AND OPERATION OF INCINERATORS
LIQUID INCINERATORS
Horizontally Fired
Monsanto operates a liquid injection incinerator to dispose of inhouse
liquid wastes and contaminated PCB's from customers. It is located at Mon-
santo's Krummricn Plant at East St. Louis, Illinois. -
The incinerator is a liquid injection type housed in a horizontal
cylinder- 20 ft long and 9.5 ft in diameter. High pressure steam is used
to atomize the waste liquid and inject it into the liquid combustor. The
typical feed rate is 2 gal/min. An additional burner uses natural gas as
an auxiliary fuel. The operating temperatures vary from 2COO to 2200°F.
The outer cylindrical shell is protected from the heat by a lining of
refractory brick. A blower supplies 25% excess air forcing the fumes frcrn
the plenum and through an oxidizer. The residence time in the oxidizer is
2 to 3 sec.H)* Tne fumes leave tne oxidizer and enter a water quench
column that reduces the temperature of the hot fumes. Particulates arp
removed in a nigh energy venturi scrubber. Finally, acidic emissions are
removed in a packed-bed scrubber at the base of the stack. The stack is
40 ft high anu equipped with a demister.
A large majority of the wastes burned in the Monsanto incinerator are
PCB derivatives from process still bottoms and contaminated transformer
oils. The heating value of tne waste is about 9000 Btu/lb. Phosphorus
compounds can not be burned because of the formation of particulates
(P^Ot,) that are not. efficiently collected by the system. The
incinerator is not equipped to handle suspended solids.
A typical liquid incineration system is shown in Figure B-l. This
unit is operated by Dow Chemical Company at their Midland, Michigan
plant. It is similar to the Monsanto incinerator described previously.
The unit has a combustion chamber 35 ft long and 10 ft square in cross
section.
Liquid wastes are fed through a combination of four dral-fired
nozzles. The exhaust gases are quenched in a spray chamber and scrubbed
in a high energy venturi scrubber and a packed-bed scrubber equipped with
*Cited references are listed at the end of this appendix ("B").
B-l
104
-------
UGUIO WASTES FROM PLANT
iEPAKAff (Af-.'KS FOR
HlGri A NO LOW
MUIING-POINT LIQUIDS
STACK 100 FT. MICH
4 fT. 6 IN. I. 0.
•i FT. 6 IN. i. o. CUTLET
LINED WITH AClO-RESlSTING
PLASTIC
VENlURI SCRLiBeE/l LINED WITH
AC!0. RESISTING ("LASTiC
\ 8ECYCLED
WASTE
WATER
I.JOOGCM.
WASTE-TAR
ftto
BURNING
TANK
fP
RELIEF
STACK
(CLOSED
CURING
OPERATION)
TEMPERING
A'R ELOwER
10,000
CU. FT./MIN.
300 GPM. \ 6frY(
\ WAST
\ WATt
\ 1.000
J
SPRAY
ChAMflER
— ^B«*
\
160 f
— \
\J-
fi
|
COM8USTION AIR 3LGw£*
10,000 CU. FT./MIN.
75 rtP.
TOTAL AIR, 26 L3./LS. WASTE
TEMPERING
Alfi SLOWER
10.000
CU. FT WIN.
25 HP.
WATER
240 GPM.
pn i.O
\ /
F-ALL
RINGS
MIST
ELIMINATOR
f
,VAUK
2,:oo GPM.
pH I .0
INDUCED-ORAF: FAN
2,oOO L8./MIN.
•15,000 CU. FT./MIN.
600 nP.
WASTE TAR FEED AvG. IOCPM.
13,00 aTu. La.
TEMPERAIURt 30-iOOOC.
VISCOSITY ISO SSu.
5 PSI TECD
4 SL'KNtKS, COMSuStiO
GAS AND IAii rjQZiLlS
5'14 - iN.CRlFiC:
Figure B-l. Diagram of horizontal liquid waste iTicinerator.
B-2
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a mist eliminator. An induced drift fan draws the oases and vapors
tnroLiuh^the system and forces the clean gas out from the 100 ft
stack.(2,3)
Many of the liquid wastes treated in trie now facility are solids at
room temperature and must be kept hot in order to remain liquid. Most of
the Bastes are chlorinated Hydrocarbons and can contain as much as bO wt%
chlorine. (<-»3)
Vertically Fired
Figure B-2 snows a vertically fired liquid waste incinerator. This
unit is desiqned and sold by Prenco Division of Picklands Kather and
Company.(4) After the retort is brought to operating temperature (1600
to 30000F) by burning natural gas, liquid waste is admittc-o to the
air-waste entrainment compartment. The aerated waste moves to the
turbulence compartment where it is mixed with more air and injected into
the high-temperature retort. The exhaust qases and any inert particles
produced flow vertically tnrough the air cone and out the top of the
retort. To handle hazardous wastes, secondary treatment equipment would
be required just as with the horizontal liquid combustors.
SOLID INCINERATORS
Fluidized Bed Incinerators(5.o,7, 8,)
Fluidized bed technoloiy from the petroleum and chemical processing
industries has been adaptec to the incineration of wasters. The most
common application involves tne disposal of sludges or slurried wastes. A
flow diagram for a typical solids disposal system utilizing fluid bed
incineration is shown in Figure B-3. The major processing steps are
listed below:
1. Grit removal to protect unit from abrasion
2. Sludge thickening
3. Solids size reduction
4. Hewatering
b. Incineration
6. Exhaust gas treatment and ash disposal.
A typical fluidized bed incinerator is shown in Figure B-4. The reactor
operates at a pressure of about 2 psiq arid a temperature of 1400 to
lb^O°F. When sand is used as the oed material the maximum temperature
is limited to 2UOO°F.(y) Lower temperature operation is avoided to
ensure odor control. The sludge is fed at the bottom of the reactor just
above the distributor plate. Fluidizing air enters below the distributor
plate. The siudge is dried and oxidized. Much of the heat o* combustion
is transferred to tne sand bed. The combustion gases and the ash leave at
the top of the reactor. An auxiliary burner is used to heat the bed to
temperature prioi to feeding sludge. Once the unit has reached tne proper
operating tempeature this auxiliary burner may be operated at partial fire
to incinerate low heat-of-combustion liquid or gaseous wastes.
B-3
106
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FREE STANDING
INTERLOCKING REFRACTORY
MODULES
TEMPERATURE MEASURING
INSTRUMENTS
EFFLUENT DIRECTLY TO ATMOSPHERE FPF,M ,,„ ,,,TA),f
OR TO SCRU8BERS AND STACK . FOR TURBO - BLOWER
AND AFTER8URBER FAN
AIR CONE
TURBO-BLOWER
IGNITION CHAMBER
HIGH VELOCITY
AIR SUPPLY
AIR-WASTE ENTRAiNMENT
COMPARlMENT
WASTE LINE
UPPER NACELLE
DECOMPOSITION CHAMBER
DECOMPOSITION STREAM
AFTER-BURNER FAN
FLAME SENSITIZER
TURBULENCE COMPARTMENT
- LOWER NACELLE
AUXILIARY FUEL LINE
TUBULAR SUPPORT COLUMNS
ELECTRICAL POWER LINE
Figure 3-2. Typical vertically fired liquid
waste incinegator.
C-4
107
-------
OTHER
LSES '
RECYCLE
WASTE
INPUT'
I
WATER CONDITIONING
FOR RECYCLE OR
DISPOSAL
MAKEUP
WASTE MATERIAL
RECEIVING AND
STORAGE
•DISCHARGE
WASTE PRE - PROCESSING
o DE - WATERING
o DISINTEGRATION
o SEPARATION
FLUIDIZED BED
INCINERATION
WASTE HEAT
UTILIZATION
ELECTRICAL
POWER GENERATION
AIR CORRECTION
EQUIPMENT
ATMOSPHERIC
DISCHARGE
Figure 3-3. Flow diagram for sludge disposal
by fluidized bed incineration.
3-5
108
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GAS
MAKEUP SAND
V
ACCESS DOOR-
i i
\ /
AUXILIARY
BURNER (OIL CR GAS)
WASTE INJECTION
FLUIDIZING AIR
ASH REMOVAL
Figure B-4. r^uidized Bed Incinerator.
O r
o-Q
109
-------
Fluidized bed incinerators are relatively new and are becoming
increasingly popular for sludge incineration. Some of the advantages of
these units are: I) good mixing of sluage and air, ?.) no moving parts
(requires less maintenance), 3) heat exchange within the sand bed (requires
fewer neat exchanges for efficient operation), and 4) sand bed service as
a heat reservoir (permitting intermittent operation without excessive
heatup).(S)
Multiple Hearth Incinerators!5,6,7,8)
The multiple hearth incinerator is widely used as an incineration
system because or its simplicity, durability, and flexibility. This type
of unit was initially designed to incinerate sewage plant sludges in 1934
and has been used quite successfully in this application,(2)
A flow sheet for a typical waste disposal plant with a multiple
hearth incinerator is shown in Figure j (Refer to main text, Chapter 5).
The solid waste is degritted and dewatsred before it is fed to the in-
cinerator. The exhaust gases are scrubbed prior to release to the
atmosphere. Ash is removed tc a landfill.
The incinerator consists of a refractory-lined circular steel shell
with refractory hearths located one abo*'e the other. Solid waste or
partially dewatered sludge is fed to the top of the unit, where a rotating
central shaft plows it across the heartn to drop holes. The uncombusted
material falls to the next heartn and the process is repeated until,
eventually, ash is discharged at the bottom. Combustion air flews counter-
current to the s lodge; the exnaust gases exit at the top of the
incinerator. In the upper zone of the incinerator the incoming solid
waste or sludge is heated by tne hot exhaust gases. Temperatures of
approx. lutiO&F are typical in tnis zone. In the middle zone volatile
gases and solids are burned at temperatures of 16UU to 13COor. In the
lower zone, fixed carbon burns at temperatures around 60QOF.(8)
An auxiliary burner is usually available for oxidizing low energy,
alternative wastes including linuids and solios.
Rotary Kiln Incinerators!6,8)
Rotary kilns are versatile units that have been used to dispose of
various solid and liquid wastes including chemical refuse, paper, wood,
obsolete chemical warfare agents, munitions, and chlorinated hydro-
carbons. (2,4,b) Kilns have been utilized in both industrial and
municipal installations arid are not typically used as sewage sludge
incineration units.
Figure B-6 shows a rotary kiln incineration facility that is operated
by Dow Chemical Company at Midland, Michigan. Solid waste is dumped into
the refuse pit where an overhead crane mixes it and raises it to the
charging hopper. While the solid waste is being fed, liquid wastes
are atomized with air and steam and are fired horizontally into the kiln.
As the refuse 'moves down the kiln the organic matter is destroyed and only
B-7
no
-------
WASTE AIR TO
ATMOSPHERE
CLEAN GASES TO
ATMOSPHERE
VACUUM
FILTERS
SLUDGES
FILTRATE
GREASE AND TARS
AIR
INDUCED
DRAFT FAN
SCRUBBERS
—« WATER
ASH TO
BLOWER DISPOSAL
ASH SLURRY TO FILTRATION AND
ASH DISPOSAL
Figure 3-5. Multiple hearth incinerator.
B-8
111
-------
s
TAR PUMPING
FACILITY
PACK STORAGE AND
'FEEDING FACILITY
SCkAP METAL
V FLY .ASH
RESIDUE
Figure B-5. .jtary kiln incinerator
B-9
112
-------
an inorganic asn remains. The ash is discharged from the end of the kiln
into ". conveyor trough that contains 3 ft of water. After quenching, the
ash is conveyed to a dumping trails- and hauled to a landfill.
After leaving the kiln, the gaseous and vapor products of combustion
enter the secondary comuustion chamber and impinge on refractory
surfaces. No secondary fuel or afterburners are used. Combustion gases
are scruboed in ?. spray tower and then exhausted to the atmospnere through
a stack.(2)
The kiln itself is a cylindrical shell lined with refractory and
mounted with its axis at a slight angle to the horizontal. Rctary kilns
are highly efficient wnen applied to solids, liquids, sludges, and tars as
it attains excel ent mixing of unburned waste and oxygen as it revolves.
Temperatures in the kiln range from 1600 to 3000°F and residence times
from seconds (gases) to hours (solids) depending on the feed naterial.
GAS INCINERATORS
Direct Flame Incineration
Direct flame incineration is normally used with materials that are at
or near their lower limit of combustion. In a well-designed combustor or
burner, gases having a heating value as low as 100 BTU/ft3 Can be burned
without auxiliary fuel.
Less combustible mixtures of organic material and air (heating values
of the order of 1-20 BTu/ft3) can be injected along with an auxiliary
fue'i directly through a ourner. However, most conventional industrial
burners require temperatures of 22UO&F or greater to sustain combustion
and tne amount of natural gas required is quite high. Since temperatures
of only 1000 to 15000F are needed for thermal incineration, it is often
more economical to heat a combustion chamber using a conventional fuel in
an industrial burner and then to inject the dilute gas into the chamber
just downstream of the flame.
Most waste gas incineration proolems involve mixtures of organic
material and air in whicn the organic material loading is very smal1.
Related to hazardous waste spills it may sometimes be desirable to
separate the waste from the spill substrate by drying (vaporization). The
vapor produced can then be incinerated in a gas incinerator.
Catalytic Incineration
Catalytic incineration is also applicable to dilute organic gas
streams. In these systems, the gas is preheated by a gas burner and then
contacts o catalyst supported in the gas. Oxidation takes place on the
surface of the catalyst. Most catalytic reactions can be carried out at
lower temperatures, (600 to 1000°F) and result in significant fuel
savings. A higher initial investment is required, however (Figure B-7).
B-10
113
-------
O3
I
CATALYST
PERFORATED
PLATE
PREHEAT
BURNERS
DISCHARGE
TO ATMOSPHERE
GASEOUS INFLUENT
CONTAINING COMBUSTIBLE
MATERIAL
Figure B-7. Catalytic incinerator with heat recovery
-------
Since transporting gases over significant distances is net economical,
gas incinerators are typically found at the sites of waste gds production.
Gas incinerators are common in the chemical process industries for
incineration of solvents and the destruction of odorous gases and vapors.
Gas incinerators are also used extensively in petroleum refiniries for the
disposal of waste vapors.
SECONDARY TREATMENT
Met Collection Equipment
Wet collection equipment can oe used to remove both gaseous
pollutants and particulate matter. In the collection of gaseous
pollutants the primary removal meuianism is the absorption of the gaseous
pollutant into a liquid, usually water. For particulate removal, tne
primary collection mechanism is tne imoaction of solid particulate
material on liquid droplets generated in the scrubber.
Spray Towers/Chambers
A spray tower is a chamber into which water or an aqueous solution is
introduced through spray nozzles. The gas stream to be cleaned passes
through tne chamber. Because of their simple design, spray towers are one
of the most economical control devices to purchase and install. They are
often used effectively for eliminating gaseous pollution when some of the
more soluole pollutants are being treated. Surface contact area, an
important consideration in qas absorption, is relatively low compared with
tnat in otner type^ of liquid scrjobers. For this reason, spray towers
must be very large to yield efficiencies equivalent to more sophisticated
liquid collection systems.
The efficiencies of spray towers for particulate removal are ratner
io.v and suitable only for removal of particulate materials ^10 microns in
size. High pressure water has been used to generate a fog spray that will
achieve collection efficiencies of the order of 90% for particles in the 1
to 2 micron range.
Packed-Bed Scrubber
A packed-bed scrubber is a tower filled with packing materials,
usually plastic, of various shapes that have a high ratio of surface area
to volume. These shapes include rings, spiral rings, and berl saddles.
Typically, scrubbing liquid passes through this type of system either
crosscurrent or countercurrent to gas flow. The interaction of the
scrubbing liquid with the packing material produces a high liquid surface
area to which the gas stream is exposed.
A condition known as flooding occurs when the upward gas velocity
reaches a point at "Jhi<-h there is a holdup of the liquid phase on the
packing. Thr, bitnation results in an increased pressure drop across the
scrubber and cntraimnent of liquid by the gas phase. Operation at prope*"
lujuid-to-gas flow ratios can achieve high gaseous pollutant removal at
relatively low gas flow pressure drops.
115
-------
Trie packed-bed scrubber is not often used strictly for particulata
removal as gas streams with high concentrations of particulates can plug
the bed. Usually, some form of dry collection equipment is used co reduce
the participate load on the packed-bed scrubber.
Wet Cyclone Scrubbers
Wet cyclones are characterized oy tangential entry of the gas stream
to be cleaned. The gas passes through the cyclone in d helical spiroid
path while the liquid is directed outward (centrifugal force) from the
center of the circular cnambe".
The wet cycline can handle high particulate loadings and produces
acceptable collection and removal efficiencies for medium sized
(>5 microns) particulate and gaseous pollutants. Where high particulate
collection efficiencies are required, a wet cyclone can be used in
conjunction with a high efficiency collection unit.
Wet Impingement Scrubbers
This class of wet collection equipment includes self-induced spray
scrubbers, orifice plate bubblers, and other scrubbers in which the
gas-liquid contact is created by impingement of the pas upon a liquid.
This type of equipment is applicable to nigh particulate loadings;
clogging is not a problem as it can be in some wet collectors.
Particulate collection efficiency approacnes 90% for particles 2 microns
and larger. Gas pollutant removal has oeen reported to be greater than
99%.
Venturi Scrubbers
In venturi scrubbers, the gas passes through a venturi-type
constriction, which produces high linear gas velocities. The scrubbing
liquid is introduced normal to the qas flow and near the minimum flow area
of the venturi. The high gas velocity atmoizes the scrubbing liquid into
fine droplets that are maintained in turbulent contact with the gas
stream.
Particulate removal in u venturi unit is directly proportional to the
gas phase energy input. Gas pressure drops of 10 to 100 in. of water are
common with particulate removal approacning 99% at higner pressure
drops.(10) Gas pollutant removal efficiencies from 60 to 99% have been
reported.
Dry Collection Equipment
Dry collection equipment is used to remove particulate pollutants and
to collect powdered solid adsorbents that have been introduced to reduce
the stream's gaseous pollutant content. These units nave little direct
effect on gaseous pollutants. Dry collectors can be used upstream of wet
scrubbers to reduce the particulate loaoing on these units.
B-13
116
-------
Mechanical Collectors
Mechanical collectors remove participate material by utilizing
centrifugal force, gravitational force, or rapid ch-anges in direction of
the particulata-laden stream. Types of equipment that fall -,n this class
are settling chambers, baffle chambers, skimming chambers, louver-type
collectors, ary cyclones, and impingement collectors. Typical mechanical
collectors have particulate collection efficiencies of around 90% for
>50 micron-size part-'-.les and bli to 90% efficiencies for 20 to 50 micron-
size particles.
Electrostatic Precipitators
Electrostatic precipitators use an electric field for charging the
particles ~;n the incoming gas stream. The charged particles then migrate
to a collecting electrode. Electrostatic orecipitators typically remove
90% of particles 2 microns and smaller.(10) Although electrostatic
precipitators require a larger initial investment than comparable wet
collectors, operating costs are significantly less. Wet electrostatic
collectors have been introduced.
Fabric Filters (Bag Houses)
Fabric filters collect particulate material as the gas stream
passes through a fabric bag. A filter-like cake builds up on the fabric
and the pressure drop tnrough the bag increases. Wnen the cake has built
up to the optimum thickness it is either shaken loose or blown off and
falls into a collection hopper. Particle collection efficiency for these
units often exceeds 99%. Fabric filters cannot be used with wet gas
streams or at high temperatures (>btKJ°F).( 10)
B-14
117
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REFERENCES
1. Federal Register, "PCB-Containing Wastes", vol. 41, no. 64, April 1,
1976, pp. I4l34-I413b.
?. Novak, R.G. "Eliminating or Disposing of Industrial Solid Wastes."
Cnemical Engineering, 77(21):79-82, October 5, 1970.
3. TRW Systems Groups, "Recommended Methods of Reduction,
Neutralization, Recovery, or Disposal of Hazardous Waste," Vol. III.
Report No. 214ob-6Ul3-JU-00. Prepared for the Environmental
frotection Agency under Contract Ho. 68-03-OO&'J.
4. Prenco. Prenco Brochure: "The Mcdern Approach r.o Liquid PoPution
Control." Detroit, Michigan, Pick lands Mather and Company. 7p.
5. BalaKrishnan, S. et al "State of the Art Review on Sludge
Incineration Practice. Prepared f-.r the Federal Water Quality
Administrction, Department of the Interior iraer Contract Nol
M-12-499. 197U.
6. TRW Systems Groups, "Recommended Methods of Reduction,
Neutralization, RFcovery or Disposal of Hazardous Waste." Vol. III.
Report No. 214dl5=bul3-RU-OG. 1973. Prepared for the Environmental
Protection Agency under Contract No. 68-03-0089.
7- Environmental Protection Agency. "Incineration in Hazardous Waste
Management." Report No. '-PA/530/SWW-141. 1975.
8. Witt, Jr., p.A. Disposal of Solid Wastes. Cnemical Engineering.
78(22):62-78, October 4, 1971.
9. TRW Defense and Space Systems Group. "Destroying Chemical Wastes in
Commercial Scale Incinerators" Prepared for the EPA under Contract
No. EPA-768-U1-2966. \'JTI.
10 Strauss, W. .'ndustrial Gas Cleaning, pp. 244-396, Perqamon Press New
York. 1966. '
8-15
118
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