EPA/540/2-88/004
September 1988
Technology Screening Guide for
Treatment of CERCLA Soils and
Sludges
Office of Solid Waste and Emergency Response
Office of Emergency and Remedial Response
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
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DISCLAIMER
This guide has been reviewed in accordance with the U.S. Environmental
Protection Agency's peer and administrative review policies and approved
for presentation and publication. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
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FOREWORD
The Environmental Protection Agency is committed to a broader use of
treatment technologies for the management of Superfund waste. These
technologies provide permanent long-term remedies which serve as
alternatives to land disposal. However, our experience with these
techniques for soils and sludges is somewhat limited, and relatively few
technologies are considered to be fully developed and available for
common use. In order to meet the goals contained in the 1986 Superfund
amendments, the Agency must rely on technologies which are currently
innovative and require further testing and development before they are
readily available for use.
This document provides a framework to assist the evaluation of
technologies in the Superfund program. The guide provides basic
information to initially screen technologies applicable to a given Superfund
site or waste. This screening helps to identify the information required to
further evaluate the treatment technologies, most of which are innovative at
this time.
The program encourages the use of these innovative technologies and
promotes their evaluation when they appear to promise better performance,
easier implementability, fewer adverse impacts, or lower costs than more
proven technologies. Relative to other, more established technologies, it is
particularly important to conduct treatability studies for innovative
approaches during the remedial investigation/feasibility study process and
to carefully consider scale-up factors.
We hope this guide will serve as a useful reference. Additional copies of
the report may be obtained at no charge from EPA's Center for
Environmental Research Information, 26 West Martin Luther King Drive,
Cincinnati, Ohio, 45268, using the EPA document number found on the
report's front cover. Once this supply is exhausted, copies can be
purchased from the National Technical Information Service, Ravensworth
Bldg., Springfield, VA, 22161, (702) 487-4600. Reference copies will be
available at EPA libraries in their Hazardous Waste Collection.
Thomas W. Devine, Director Henry L. Longest II, Director
Office of Program Management Office of Emergency and
and Technology Remedial Response
in
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PREFACE
This guide is intended to disseminate information on technologies
available at this time for treating CERCLA wastes in soils and sludges. The
technology data were obtained from individual treatment technology
vendors. The data have been reviewed by representatives of the U.S.
Environmental Protection Agency's Office of Emergency and Remedial
Response, Office of Solid Waste, and Office of Research and Development.
IV
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ABSTRACT
The Technology Screening Guide for Treatment of CERCLA Soils and
Sludges is a guide for screening feasible alternative treatment technologies
for soils and sludges at Superfund sites. The guide provides a screening
methodology to identify treatment technologies that may be suitable for the
management of soils and sludges containing CERCLA wastes.
A simplified screening methodology flowchart presents the decision
steps necessary to identify suitable treatment technologies, while the
waste/technology matrix tables included in this guide can be used to
ascertain whether the treatment technologies have demonstrated
effectiveness, potential effectiveness, or no effectiveness in the treatment of
organic, inorganic, and reactive wastes or whether the technologies could
adversely impact the environment.
For each of the treatment technologies, information is presented on (a)
the generic system, (b) individual, unique systems, (c) developmental
status, (d) process schematics, (e) characteristics affecting treatment
performance, and (f) contacts. Some limited information is also presented
about pretreatment, materials handling, and residuals management
requirements.
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TABLE OF CONTENTS
Section Page No.
EXECUTIVE SUMMARY 1
1 INTRODUCTION 3
2 USING THIS GUIDE 7
2.1 Waste Characteristics 7
2.1.1 Waste Matrix 7
2.1.2 Waste Constituents 9
2.1.3 Other Characteristics Impacting
Technology Applicability 9
2.2 Waste/Technology Tables 9
2.3 Technology Restriction Tables 15
2.4 Pretreatment Tables 16
2.5 Examples for Using this Guide 22
2.5.1 Example for a Single Waste Group 22
2.5.2 Example for Multiple Waste Groups 22
3 APPLICATION OF THIS GUIDE TO A HYPOTHETICAL WASTE 25
APPENDICES 31
APPENDIX A. THERMAL TREATMENT TECHNOLOGIES 33
Introduction 33
A.1 Fluidized Bed Incineration 35
A.2 Rotary Kiln Incineration 40
A.3 Infrared Thermal Treatment 43
A.4 Wet Air Oxidation 47
A.5 Pyrolytic Incineration 52
A.6 Vitrification 55
References 60
APPENDIX B. PHYSICAL/CHEMICAL TREATMENT TECHNOLOGIES 61
Introduction 61
B.1 Chemical Extraction 63
B.2 In Situ Chemical Treatment 68
B.3 Soil Washing 72
B.4 In Situ Soil Flushing 77
B.5 Glycolate Dechlorination 80
vii
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Section Page No.
B.6 Low Temperature Thermal Stripping 83
B.7 In Situ Vacuum and Steam Extraction 86
B.8 Stabilization/Solidification 90
B.9 Chemical Reduction-Oxidation 95
B.10 In Situ Vitrification 98
References 102
APPENDIX C. BIOLOGICAL TREATMENT TECHNOLOGIES 103
Introduction 103
C.1 Biodegradation 104
C.1.1 Composting 104
C.1.2 Slurry-Phase Treatment 104
C.1.3 Solid-Phase Treatment 105
C.2 In Situ Biodegradation 111
References 116
APPENDIX D. SELECTED REFERENCE TABLES 117
VIII
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FIGURES
Figure No. Page No.
1 Screening Methodology Flowchart 8
2 Technology Screening Procedure for a Hypothetical Waste . 26
A.1-1 Fluidized Bed Incineration 37
A.1-2 Circulating Bed Combustor 38
A.2-1 Rotary Kiln Incineration 41
A.3-1 Infrared Thermal Treatment 45
A.4-1 Wet Air Oxidation 49
A.4-2 Supercritical Water Oxidation Unit 50
A.5-1 Pyrolytic Incineration System 53
A.6-1 Vitrification ("Electric Pyrolyzer") 57
A.6-2 Vitrification ("Pyrolytic Centrifugal Reactor") 58
B.1-1 Chemical Extraction ("BEST") 65
B.1-2 Critical Fluid Solvent Extraction 66
B.2-1 In Situ Chemical Treatment ("Detoxifier") 70
B.3-1 Soil Washing System 74
B.3-2 Soil Washing 75
B.4-1 In Situ Soil Flushing 78
B.5-1 Glycolate Dechlorination 81
B.6-1 Low Temperature Thermal Stripping 84
B.7-1 In Situ Vacuum Extraction 88
B.8-1 Stabilization/Solidification 92
B.9-1 Chemical Reduction-Oxidation 96
B.10-1 In Situ Vitrification 100
C.1-1 Slurry-Phase Biodegradation 107
C.1-2 Solid-Phase Biodegradation 108
C.2-1 In Situ Biodegradation 113
IX
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Table No. Page No.
1 Examples of Constituents Within Waste Groups 10
2 Waste/Technology Matrix: Soils 13
3 Waste/Technology Matrix: Sludges 14
4 Pretreatment/Materials Handling Table: Sludges 17
5 Pretreatment/Materials Handling Table: Soils 18
6 Residuals Management 20
A-1 High Temperature Thermal Treatment (General)--Soils
and Sludges 34
A.1-1 Fluidized Bed Incineration-Soils and Sludges 39
A.2-1 Rotary Kiln Incineration-Soils and Sludges 42
A.3-1 Infrared Thermal Treatment-Soils and Sludges 46
A.4-1 Wet Air Oxidation-Sludges 51
A.5-1 Pyrolytic Incineration-Soils and Sludges 54
A.6-1 Vitrification-Soils and Sludges 59
B.1-1 Chemical Extraction - Soils and Sludges 67
B.2-1 In Situ Decontamination-Soils and Sludges 71
B.3-1 Soil Washing-Soils 76
B.4-1 In Situ Soil Flushing-Soils 79
B.5-1 Glycolate Dechlorination-Soils and Sludges 82
B.6-1 Low Temperature Thermal Stripping-Soils 85
8.7-1 In Situ Vacuum and Steam Extraction-Soils 89
B.8-1 Stabilization/Solidification-Soils and Sludges 93
B.9-1 Chemical Reduction-Oxidation-Sludges 97
B.10-1 In Situ Vitrification-Soils and Sludges 101
C.1-1 Biodegradation-Soils and Sludges 109
C.2-1 In Situ Biodegradation-Soils and Sludges 114
D.1 Examples of Constituents Within Waste Groups 118
D.2 Waste/Technology Matrix: Soils 121
D.3 Waste/Technology Matrix: Sludges 122
D.4 Pretreatment/Materials Handling Table: Sludges 123
D.5 Pretreatment/Materials Handling Table: Soils 124
D.6 Residuals Management 126
XI
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ACKNOWLEDGMENTS
This guide was prepared by Tim Holden, John Newton, Paul Sylvestri,
and Max Diaz of Versar Inc., Springfield, Virginia, and Colin Baker of Camp,
Dresser & McKee of Boston, Massachusetts, for the U.S. Environmental
Protection Agency in fulfillment of Contract 68-01-7053. Editing and
technical content of this report were the responsibilities of the contractor.
This document should not be viewed as a statement of Agency policy.
The authors wish to acknowledge the assistance of several individuals
and organizations that have made significant contributions to this study of
hazardous waste treatment and management. This includes the exceptional
guidance and review of drafts during the study provided by Linda Galer,
John Kingscott, and Don White of the Office of Emergency and Remedial
Response. Substantial contributions were made during data collection and
document review by the Office of Solid Waste, including members of the
Waste Treatment Branch, and by the Office of Research and
Development's Risk Reduction Engineering Laboratory in Cincinnati, Ohio.
We would like to recognize the data gathering and collection efforts
provided by Camp, Dresser & McKee, in particular the work of Colin Baker.
The authors would like to express particular gratitude to the Versar
production team, including the editors headed by Juliet Crumrine, and
particularly Martha Martin, the typists, and the artists for their many long
hours producing the numerous drafts of this extensive report.
Finally, the authors would like to acknowledge the members of the study
team who played such an important role in assembling these data,
developing the methodology, and preparing the technology writeups.
Study Team
Linda Galer EPA Work Assignment Manager
Tim Holden Versar Task Manager
John Newton Principal Investigator
Paul Sylvestri Study Engineer
Maximo Diaz Study Engineer
Thomas Drygas Engineering Review - Thermal Treatment
Technologies
Rajani Joglekar Engineering Review - Physical/Chemical and
Biological Treatment Technologies
Jerome Strauss Versar Program Manager
XII
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EXECUTIVE SUMMARY
This document is a guide for the screening of alternative treatment
technologies for contaminated so//s and sludges at CERCLA sites. The
guide has been developed to help those responsible for remedy selection
to identify potentially applicable treatment systems for the remediation of
uncontrolled hazardous waste sites. It contains technical information useful
for determining the feasibility and availability of 18 different treatment
technologies without consideration of cost. Some of the technologies are
still innovative, are not fully developed, and are not available for immediate
use. This guide is intended for use as a screening tool to facilitate the
scoping of site investigations and feasibility studies. This guide is not a
substitute for in-depth engineering analyses.
The application of many of the innovative technologies discussed here
has not been fully established. Therefore, judgment was often required to
assess technology applicability and limiting factors. Some readily available
references were used; however, an exhaustive literature search was beyond
the scope of this effort.
Included in the first part of this document are a methodology and
accompanying matrices that can be used to screen wastes for feasible
treatment technologies. The screening can be performed for both wastes in
soils and wastes as sludges. Liquid wastes are not addressed directly;
however, liquids produced in the treatment process are identified, and
associated information on residuals management is provided in a table.
Informational tables on waste pretreatment and materials handling for soils
and sludges are also provided. The result of the technology screening will
be a list of potentially feasible treatment options for the waste.
Appendices A, B, and C present information on the individual treatment
technologies that could appear on the screening list. For each technology,
the document presents a brief description of the generic process;
information on individual, available systems, including unique capabilities; a
discussion of parameters that can affect system operation; and a listing of
selected EPA contacts and vendors. Generic flow diagrams of technologies
or, where available, diagrams of specific systems are presented. Finally, for
each technology, a table is provided that lists waste characteristics
impacting process performance, the reasons that the characteristics may
restrict operation, and types of analyses needed to identify the presence of
such characteristics. This information can be used to develop plans for site
sampling and analysis. The table also gives references that provide
additional information about the potential problem.
Where available, quantitative data on restrictive characteristics have
been included in the tables to assist the user in evaluating potential
technologies. The data have been extracted from sources addressing the
technology generically and from sources, including vendors, that describe a
specific treatment system. The data should be used only as guidelines,
they may not be transferable to every application and are not intended as a
substitute for case-specific assessments by qualified professionals.
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The guide can be used iteratively to further refine technology options as
additional data are obtained. However, this guide is designed only to assist
in screening alternative technologies and in identifying the data collection
requirements needed to evaluate technical feasibility. The applicability and
availability of potential technologies thus identified must be further
evaluated by using the references provided, contacting technology experts
(including vendors), performing bench and/or pilot testing as necessary,
and considering site-specific circumstances on a case-by-case basis.
Treatability testing may be required to determine the applicability of some
technologies. This is particularly true for the innovative, undemonstrated
technologies and technologies whose effectiveness is highly dependent on
the characteristics of the waste.
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Section 1
Introduction
In the Superfund Amendments and Reauthorization Act of 1986 (SARA),
Congress directed the U.S. Environmental Protection Agency (EPA) to
promote the development of alternative and innovative treatment
technologies for use in Superfund response actions. Similarly, the
Hazardous and Solid Waste Amendments of 1984 (HWSA) to the Resource
Conservation and Recovery Act (RCRA) emphasize the treatment of
hazardous waste through the phased prohibition of land disposal of
untreated hazardous wastes. Therefore, Congress has clearly directed the
Agency to reduce the reliance on land disposal of wastes through the
development and increased use of alternative treatment technologies.
This guide for the screening of treatment alternatives for soils and
sludges has been developed to help identify potentially applicable
treatment technologies for the remediation of uncontrolled hazardous waste
sites. The guide is not designed to serve as the sole basis for selection of a
technology for a particular waste, but rather to identify the treatment
technologies potentially applicable to that waste based on technical
feasibility, not cost. Information on widely available, commercially
demonstrated technologies (e.g., incineration) as well as undemonstrated
innovative technologies (e.g., in situ soil flushing) has been included in this
guide. Judgment was often required to assess the applicability of these
newer techniques. Furthermore, some readily available references were
used, but the scope of the document did not include a thorough literature
search. Therefore, this guide is intended for use as a reference and is not
intended to replace the judgment of qualified professionals. Each situation
must be addressed on a case-by-case basis, considering the site-
specific circumstances and the status of technologies as they develop over
time.
This guide does not evaluate treatment technologies for liquid wastes but
focuses instead on soils and sludges, for which the greatest innovation and
challenge currently exist. However, the management of liquid residuals from
the treatment of soils and sludges is addressed.
Screening is accomplished by use of waste/technology tables and
technology restriction tables. These are used to analyze potentially
applicable technologies by:
1. Identifying treatment units potentially applicable to the remediation of the
many types of waste found at CERCLA sites; and /
2. Identifying interfering waste and/or site characteristics, treatment process
limitations, pretreatment options, and management of treatment
residuals, all of which must be considered when evaluating a potential
treatment system in detail.
The above information is provided in four groups of tables:
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(1) waste/technology tables for sludges and soils, (2) technology
restriction tables for all the technologies, (3) pretreatment tables to identify
potential pretreatment and materials-handling systems, and (4) a residuals
management table. The tables are designed to be used by both technical
and nontechnical personnel with a general scientific background.
The guide also identifies for some technologies an EPA contact who is
familiar with the operation and limitations associated with the technology. A
complete reference of knowledgeable individuals within and outside of EPA
is beyond the scope of this document.
In addition, for those technologies that have only one or a few
developers, the company name and contact for some of the "vendors"
have been included to assist the user in gathering additional information
about the technologies' limitations and/or applicability, availability, and cost.
Inclusion of a developer in this guide in no way implies an EPA
endorsement of the technology or developer. Developers have been
included only to assist users in screening potentially applicable tech-
nologies. Furthermore, a comprehensive listing of all vendors offering the
technologies discussed was beyond the scope of this document.
The principal information provided in this guide is contained in the
technology restriction tables. These tables assist in identifying waste, site,
and technology factors that should be considered in the evaluation or
implementation of treatment systems. Specifically, the tables identify the
data necessary for a more detailed evaluation of the technologies. Once
these data are collected, the guide can be used to focus on potentially
applicable technologies warranting further evaluation. A more detailed
analysis of each potentially applicable treatment alternative identified by
this guide would include assessments of cost, performance, and
environmental impacts and the availability of fulll-scale commercial units.
In particular, bench- and/or pilot-scale treatability studies may be
required before the actual applicability and performance of many
technologies can be determined. This guide is not meant to be used for
such in-depth analyses; it is designed to provide a preliminary screening
of treatment alternatives and to identify data needs.
The initial step in using this guide is to determine whether the waste is a
soil or sludge and to identify the contaminants requiring treatment. This
information allows the user to place the waste into broad waste groups
using Table 1. Next, technologies with demonstrated or potential
effectiveness on the waste groups can be identified using Table 2 or 3.
Each technology can then be further evaluated and data needs identified by
referring to the technology description and the technology restriction table
that follows each description. The effectiveness values shown in Tables 2
and 3 are based on the characteristics affecting performance that are
described in the technology writeups. It is important to note that
modifications to technologies and/or pretreatment of the waste may
preclude restrictions to the use of a treatment.
The pretreatment tables (Tables 4 and 5) identify potential techniques to
make the waste more amenable to treatment. Many wastes require
pretreatment prior to the use of a principal treatment method. It is important
to assess the potential for waste pretreatment before eliminating a principal
technology from consideration. Finally, the residuals management table
(Table 6) outlines general options for handling potential treatment residuals.
When using Table 1 to evaluate wastes that can be placed into two or
more groups (i.e., complex wastes), each waste group should initially be
treated separately to develop a list of potentially applicable treatment
technologies. The technology lists can then be compared to determine if
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one technology can treat all the waste groups or whether a sequence of
treatments (i.e., treatment train) may be required. Treatment train
development is discussed in further detail in Sections 2.5 and 3. As the
user obtains more information about waste characteristics, this guide can
be used to help further refine the list of potentially applicable technologies.
As stated earlier, however, the guide is intended for use as a reference only
and does not contain sufficient information to fully evaluate treatment
technologies.
The contents of this guide are organized into three sections and four
appendices as follows:
• Section 2 describes how to use this guide by outlining the waste
characterization process, describing the waste/technology tables and
explaining how the effectiveness of the technologies was determined;
discussing the content and utility of the technology restriction tables;
summarizing the purpose and use of the pretreatment tables and
residuals management table; and presenting a step-by-step approach
for the proper use of this guide.
• Section 3 illustrates how to use the guide by working through a
technology screening for a hypothetical waste.
• Appendix A describes thermal treatment technologies and includes a list
of applicable references.
• Appendix B describes chemical/physical treatment technologies and
includes a list of applicable references.
• Appendix C describes biological treatment technologies and includes a
list of applicable references.
For each technology a generic description is presented, followed by
examples and illustrations of systems provided by individual vendors. Note
that the illustrations are only examples; in most cases, many configurations
and add-ons are possible.
• Appendix D repeats several key tables for easy reference.
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Section 2
Using This Guide
To use this guide to screen potentially applicable technologies, the user
must first determine whether the waste of concern is a sludge or soil and
must identify the contaminants that require treatment. The guide then
provides information that facilitates the selection of technologies that may
apply to the site and identifies the additional data required to further
evaluate these technologies. This approach allows the screening of
technologies early in the study of a site and the identification of data needs
that should be considered in the scoping of the site sampling plan and site
feasibility studies. For instance, the potential need for treatability studies
can be assessed.
The screening methodology for selecting potential technologies is shown
as Figure 1. Generally, the methodology involves:
• Identification of waste constituents (see Section 2.1);
• Selection of effective or potentially effective technologies from the
appropriate tables for the identified waste constituents (see Section 2.2);
• Generation of a list of all potential technologies for the entire waste;
• Review of the technology writeups to determine how well the technology
may be expected to perform (see Section 2.3 and the appendices);
• Determination of pretreatment and residuals management needs (see
Section 2.4); and
• Identification of data collection needs and requirements for treatment
testing.
Simple examples of how to implement the methodology for single and
multiple wastes are provided at the end of this section.
2.1 Waste Characteristics -~
In order to conduct even a preliminary screen of technologies, wastes
must be categorized by certain fundamental characteristics. The two
principal waste characteristics used in this guide for initial technology
screening are waste matrix and waste constituents. Once technologies have
been identified based on matrix and constituents, further screening is
possible using other waste characteristics impacting technology
applicability and performance. These further waste attributes are identified
in the technology summaries.
2,1.1 Waste Matrix
Moisture content appears to be a key factor in distinguishing how soils,
sludges, and liquids can be treated and handled. Thus, this guide uses
moisture content to determine whether the waste should be considered a
soil or a sludge. It is recognized that many varying definitions can be used
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Figure 1. Screening methodology flowchart.
Identify Waste Matrix,
Contaminants of Concern,
and Waste Groups
(Table 1)
Generate List of
Potential Technologies
for Soils (Table 2) or
Sludge (Table 3)
Develop Treatment
Scenarios Addressing
Individual Waste Groups
Sequentially in Trains
Develop Treatment
Scenarios Addressing
Multiple Waste Groups
Concurrently
Review Technology
Summaries and Tables
for Limiting
Characteristics
Consult Pretreatment
(Table 4) and Residuals
Management (Table 5)
Screen Alternatives to
Determine Feasible
Scenarios
Identify Data Needs
and Contacts
Conduct Additional Waste
Characterization
* Refine Treatment
Alternatives
I
Finalize Treatment
Technologies to be
Considered Further
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for soils and sludges, but for the purpose of this guide, sludges are defined
as pumpable materials of both natural and man-made origin with a solids
content ranging from 10 to 85 percent. Wastes with a water content greater
than 90 percent are considered liquids. Furthermore, for the purpose of this
document, soils are naturally occurring earth materials, not meant to include
end-of-pipe manufacturing wastes. Generally, soils have a moisture
content of 10 to 20 percent or less. It should be noted that the EPA has
other definitions for these matrices derived for other purposes.
2.1.2 Waste Constituents '
Chemical constituents are the second basis for characterizing waste
treatability so that technologies can be screened. Chemical constituents can
be grouped in general categories according to their chemical nature (e.g.,
organics and metals). Table 1 provides examples of waste constituents
within a waste group. These waste groups provide the basis for selecting
potential treatment technologies. It is important to note, however, that
categorizing constituents by waste group may oversimplify treatability
categories. For some technologies such as biodegradation, treatability of
compounds within a waste group may differ substantially. In addition,
contaminated soils and sludges often contain more than one waste group;
to use the guide properly, all waste groups requiring treatment must be
identified.
2.7.3 Other Characteristics Impacting Technology Applicability "
Other waste characteristics and site factors can influence treatability.
Discussions of the impact of these factors on treatability are contained in
the technology restriction tables provided in the appendices. Examples of
key waste characteristics affecting treatability for soils treatment include:
grain size, organic content, pH, moisture content, soil/solvent reactions,
metals content, and the presence of various elements in the soil.
As an example, grain size affects most of the soil treatment
technologies. For soil washing and in situ soil flushing, homogeneous soil is
desirable because inconsistent flushing generally occurs in soil with highly
variable grain size. Stabilization also can be affected by grain size. Silt and
clay, which contain grain sizes of less than 0.0625 mm, (<200 sieve mesh)
may coat large contaminants like a dust layer, thereby weakening bonds
formed during the stabilization process. Soils of low permeability (i.e., soils
of high silt or clay content) can cause reduced percolation and leaching
capabilities, as well as reduced solid/liquid separation in soil washing or
flushing.
Organic content is another important characteristic in the screening of
treatment technologies. Organic content can affect the performance of
cement-based stabilization by reducing the binding capacity of the fixative
and may cause premature structural degradation. Decomposition of organic
material can also result in increased permeability of the final product in
stabilization/solidification processes. Excessive organic content can affect
soil washing and flushing as well, by inhibiting the desorption of
contaminants.
2.2 Waste/Technology Tables
This guide contains two waste/technology tables, Table 2 for soils and
Table 3 for sludges, designed to identify the effectiveness and/or potential
applicability of technologies to some or all compounds within specific waste
groups. The waste/technology tables assume that the user has
characterized the waste by matrix, principal contaminants, and waste
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Table 1
Examples of Constituents Within Waste Groups.
HALOGENATED VOLATILES
Bromodichloromethane
Bromoform
Bromomethane
Carbon tetrachloride
Ch/orodibromomethane
Chlorobenzene
Ch/oroethane
Chloroform
Chloromethane
Chloropropane
D/bromomethane
Cis,l,3-dichloropropene
1,1 -Dichloroethane
1,2 -Dichloroethane
1,1-Dictiloroethene
1,2-Dichloroethene
1,2-Dichloropropane
Fluorotnchloromethane
Methylene chloride
1,1,2,2-tetrachloroethane
Tetrachloroethene
1,1,1 -Tnchloroethane
1,1,2-Trichloroethane
1,2-Trans-dichloroethene
Trans-1,3-dichloropropene
l,l,2-trichloro-l,2,2-trifluoroethane
Tnchloroethene
Vinyl chloride
Total chlorinated hydrocarbons
Hexachloroethane
Dichloromethane
HALOGENATED SEMIVOLATILES
2-chlorophenol
2,4-dichlorophenol
Hexachlorocyclopentadiene
p-chloro-m-cresol
Pentachlorophenol
Tetrachlorophenol
2,4,5-trichlorophenol
2,4,6-trichlorophenol
Bis-(2-chloroethoxy)methane
Bis(2-chloroethyl)ether
Bis(2-chloroisopropyl)ether
4-bromophenyl phenyl ether
4-chloroanilme
2 -chloronapthalene
4-chlorophenyl phenylether
1,2 -dichlorobenzene
1,3 -dichlorobenzene
1,4-dichlorobenzene
3,3-dichlorobenzidine
Hexachlorobenzene
Hexachlorobutadiene
1,2,4 -trichlorobenzene
HALOGENATED SEMIVOLATILES (cont)
Bis(2-chloroethoxy)phthalate
Bis(2-chloroethoxy)ether
i,2-bis(2-chloroethoxy)ethane
NONHALOGENATED VOLATILES
Acetone
Acrolem
Acrylonitrile
Benzene
2-butanone
Carbon disulfide
Cyclohexanone
Etfiyl acefafe
Ethyl ether
Ethyl benzene
2-hexanone
Isobutanol
Methanol
Methyl isobutyl ketone
4-methyl-2-pentanone
n-butyl alcohol
Styrene
Toluene
Trimethyl benzene
Vinyl acetate
Xylenes
NONHALOGENATED SEMIVOLATILES
Benzoic acid
Cresols
2,4 -dimethylphenol
2,4-dmitrophenol
2-methylphenol
4-methyl phenol
2-nitrophenol
4-nitrophenol
Phenol
Acenaphthene
Acenapthylene
Anthracene
Benzidine
Benzo(a)anthracene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Benzo(a)pyrene
Benzo(ghi)perylene
Benzyl alcohol
Bis(2-ethylhexyl)phthalate
Butyl benzyl ph thai ate
Chrysene
Dibenzo(a,h)anthracene
Dibenzofuran
Diethyl phthatate
Dimethyl ph thai ate
Di-n-butyt phthalate
10
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Table 1
Examples of Constituents Within Waste Groups (continued).
4,6-dinitro-2-methylphenol
2,4-dinitrotoluene
2,6-dinitrotoluene
Di-n-octyl phthalate
1,2-diphenylhydrazine
Fluoranthene
Fluorene
lndeno(l,2,3-cd)pyrene
Isophorone
2-methylnapthalene
Napthalene
2-nitroaniline
3-nitroaniline
4-nitroaniline
Nitrobenzene
n-nitrosodimethylamine
n-nitrosodi-n-propylamme
n-mtrosodiphenylamine
Phenanthrene
Pyrene
Pyridine
2-methynaphthalene
Bis phthalate
Phenyl napthalene
PESTICIDES
Aldrm
Bhc-alpha
Bhc-beta
Bhc-delta
She-gamma
Chlordane
4,4'-ODD
4,4'-DDE.
4,4'-DDt
Dieldrin
Endosulfan I
Endosulfan II
Endosulfan sulfate
Endrin
Endnn aldehyde
Ethion
Ethyl parathion
Heptachlor
Heptachlor epoxide
Malathion
Methyl parathion
Parathion
Toxaphene
VOLATILE METALS
Arsenic
Bismuth
VOLATILE METALS (cont)
Lead
Mercury
Tin
Selenium
OTHER CATEGORIES
Asbestos
INORGANIC CORROSIVES
Hydrochloric acid
Nitric acid
Hydrofluoric acid
Sulfuric acid
Sodium hydroxide
Calcium hydroxide
Calcium carbonate
Potassium carbonate
PCBs
PCB(Arochlor)-1016
PCB(Arochlor)-1221
PCB (Arochlor)-1232
PCB (Arochlor)-1242
PCB (Arochlor)-1248
PCB (Arochlor)-1254
PCB (Arochlor)-1260
PCB NOS (not otherwise specified)
ORGANIC CORROSIVES
Acetic acid
Acetyl chloride
Aniline
Aromatic Sulfonic acids
Cresylic acid
Formic acid
NONMETALLIC TOXIC ELEMENTS
Fluorine
Bismuth
NONVOLATILE METALS
Aluminum
Antimony
Barium
Beryllium
Bismuth
Cadmium
Calcium
Chromium
Copper
Cobalt
Iron
Magnesium
11
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Table 1 Examples of Constituents Within Waste Groups (continued).
NONVOLATILE METALS (cont) ORGANIC CYANIDES
Manganese Organonitriles
Nickel
Potassium INORGANIC CYANIDES
Selenium Cyanide
Sodium Metallic cyanides
Vanadium (e.g., ferricyanide,
Zinc sodium cyanide)
RAD.OACTIVES
Radioactive ,sotopes of Chromates
iodine, barium, uranium
. . . REDUCERS
Gamma radioactivity Sulfides
Radon; alpha radioactivity Phosphides
Hydrazine
groups (Table 1). The waste groups are listed vertically down the left
margin, and the technologies are listed horizontally across the top of each
table.
The waste groups in the waste/technology tables are organized in a
manner that generally reflects similar treatability characteristics (e.g.,
volatility, biodegradability, heating value). Certain contaminants such as
RGBs and pesticides are presented separately from other halogenated
organics for easy reference.
Some of the technologies included in this guide may be used primarily
for volume reduction, waste separation, or other pretreatment and may not
completely treat or destroy the constituents of concern (e.g., chemical
extraction). They have been included because they represent a significant
step in the overall management of a waste.
The following descriptors are used to characterize the applicability of the
technologies to each waste group:
1. Demonstrated effectiveness - (Symbol •). The technology has been
used successfully on a commercial scale for treating CERCLA wastes in
repeated applications (e.g., rotary kiln incineration of most organics).
2. Potential effectiveness - (Symbol Q). The technology appears to have
the basic characteristics needed for successful application but has not
been proven for specific CERCLA wastes on a commercial scale or on a
continuous basis. That is, successful treatment technology tests of
(1) RCRA wastes or other CERCLA wastes on a commercial scale or
(2) CERCLA wastes on a demonstration or pilot scale, indicate potential
effectiveness of the technology. In many cases the commercial
technology will require further demonstration and development before it
is ready for use in site remediation. Effectiveness may depend on
specific waste or soil characteristics (e.g., soil flushing of organics
depends on soil permeability), or pretreatment may be required. The
potential for negative impacts on the environment is uncertain and
should be evaluated on a case-by-case basis. A decision on feasibility
requires careful consideration of waste-related limitations (i.e., waste
characteristics that affect performance) or mixture interferences and may
12
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Table 2
Waste Technology Matrix: Soils.
[Contaminant fej
Organic Table
1 Fluidized bed incineration
1 Rotary kiln incineration
Infrared thermal treatment , ..
1 Pyrolysis-incineration co l^ oo T- T- CM
<<<<
-------
Table 3
Waste Technology Matrix Sludges.
[ Contaminant
Organic Table
Halogenated volatiles
Halogenated semivolatiles
Nonhalogenated volatiles
Nonhalogenated semivolatiles
PCBs
Pesticides
Organic cyanide
Organic corrosives
Inorganic
Volatile metals
Nonvolatile metals
Asbestos
Radioactive materials
Inorganic corrosives
Inorganic cyanides
Reactive
Oxidizers
Reducers
.g
03
73
'x
O
c
O
I
c
O
.1
Bog,
.— *-• m
(0
T3
03
= o 4=
LL CC =
> O -E (5 W
-5 S .2 5>
± ^ ^ -s
8 "5 Ij
e .if 3
* <" ^ 'io
6 ^ii^
T^CMCO •^Lnco-^cviLqoq
<<< <<
-------
require bench- and/or pilot-scale testing. Indication of potential
effectiveness of a technology to a waste group does not signify
applicability to all chemical compounds within the waste group.
3. No effectiveness - (Symbol 0). The technology is not expected td
remove or destroy the contaminant to a significant degree, but the
contaminant does not interfere with or adversely impact the process
(e.g., vacuum extraction, used to remove volatile organics, neither treats
nor is affected by metals in the soil).
4. Adverse impacts - (Symbol X). The contaminant is likely to interfere
with or adversely impact the environment or the safety, effectiveness, or
reliability of the treatment process (e.g., the adverse impact of high
concentrations of available biotoxic metals on in situ biodegradation for
soils). Note that such adverse impacts may only occur above some
threshold concentration, and pretreatment may alleviate the adverse
impact. Refer to the technology summaries and tables for the specific
nature of the adverse impact.
2.3 Technology Restriction Tables
Following the identification of potentially applicable treatment
technologies on Tables 2 and 3, the user should refer to the appropriate
technology restriction tables (provided in the appendices) to identify
potentially restrictive waste and/or matrix (i.e., soil or sludge) characteristics
that can interfere with process feasibility and/or operation. To determine
whether these restrictive characteristics apply to the specific waste to be
treated, additional data on the waste or soil may be required. These general
data collection requirements are given in the technology restriction tables
provided in the appendices.
Where available, data on restrictive characteristics have been included in
the technology restriction tables to assist the user in evaluating potential
technologies. The data have been extracted from sources addressing the
technology generically and from sources, including vendors, that describe a
specific treatment system. The data should be used only as a guideline or
estimate for applicability purposes; they are not transferable to every
application and are not intended as a substitute for case-specific
assessments by qualified professionals.
A preliminary screening of remedial alternatives, detailed
characterization of the site, and analysis of remedial alternatives are the
next steps in the site remediation process. This guide is designed to make
these steps more efficient by focusing on potentially applicable
technologies and the data collection requirements needed to evaluate them.
This guide facilitates identification of each technology based on the
characteristics of the site and waste. Consequently, this guide is not
intended to replicate the site and alternatives evaluation, but is intended
only to help identify those technologies worthy of further evaluation.
The technology restriction tables can be used at several stages of the
remedial investigation or site-sampling process to support characterization
of the technical feasibility of a treatment method. However, this guide is
designed only to assist in screening alternative technologies and in
identifying the data collection requirements needed to evaluate technical
feasibility. The potential technologies thus identified must be further
evaluated by using the references provided, contacting technology experts
(including vendors), performing bench- and/or pilot-scale testing as
necessary, and considering site-specific circumstances on a case-by-
case basis. Treatability testing may be required to determine the
15
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applicability of some technologies. This is particularly true for the
innovative, undemonstrated technologies (e.g., soil washing, soil flushing,
and in situ biodegradation) and the technologies whose effectiveness is
highly dependent on the characteristics of the waste (e.g., stabilization).
2.4 Pretreatment and Residuals Management Tables *
As discussed in previous sections, the technology restriction tables
identify characteristics of wastes and sites that may affect the feasibility of
using a technology. The effects of many of these potentially restrictive
characteristics can be eliminated or reduced through pretreatment of the
waste. In many cases, wastes will require pretreatment before they can be
treated by any method. In addition, wastes normally will need to be
excavated and/or transported to the treatment unit. Therefore, for the
purposes of this guidance, waste materials handling is included as part of
pretreatment.
Pretreatment, materials handling, or processing requirements for a waste
are often not recognized until the advanced stages of pilot testing or
implementation of a treatment system. This may cause significant delays
and escalate costs while the waste or equipment is modified. For example,
vendors of soil-washing and mobile incineration systems often have cited
materials handling and processing as the key problems at a site rather than
the technical performance of the system.
This guide contains two pretreatment/materials handling tables: one for
sludges (Table 4) and one for soils (Table 5). These tables provide general
examples of how some common restrictive characteristics can be
pretreated. The tables also present some common materials handling
techniques. Whenever possible, an attempt has been made to alert the user
to those restrictive characteristics identified in the technology restriction
tables that may possibly be handled through pretreatment by referencing
the appropriate pretreatment/materials handling table.
These tables are not designed to identify every possible
pretreatment/materials handling technique for each restrictive characteristic.
Instead, they are designed to be used as a starting point and to convey to
the user that the presence of restrictive characteristics should not
necessarily eliminate a technology from consideration.
As a final table to facilitate selection of potential treatment technologies,
Table 6 presents a listing of the probable residual streams produced by
treatment. Ways of managing the residuals, such as stabilization of
incinerator ashes or biological treatment of leachates with trace quantities of
organics, are also cited.
16
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Table 4
Pretreatment/Materials Handling Table: Sludges.
Problem
Solution
Comments
Material Dragline
transport and
excavation
Backhoe,
excavator
Mudcat
Positive
displacement
pump (e g.,
cement pump)
Moyno pump
Excessive Evaporator
water content
Filter press
Belt filter
Vacuum filter
Centrifuge
(solid bowl)
Drying
Gravity
thickening
Chemical
addition
Crane-operated excavator bucket to dredge
or scrape sludge from lagoons, ponds, or
pits.
Useful for subsurface excavation or at the
original ground level.
Bulldozer or loader much like a crawler
capable of moving through sludge.
Pump that can handle high-density sludges
containing abrasives such as sand and
gravel.
Progressing cavity pump that can pump
high-viscosity sludges.
Excess water can be evaporated from
sludge. The Carver-Greenfield process is a
potentially applicable technology. The sludge
is mixed with oil to form a slurry, and the
moisture is evaporated through a multiple-
effect evaporator.
Sludge is pumped into cavities formed by a
series of plates covered by a filter cloth. The
liquid seeps through the filter cloth, and the
sludge solids remain.
Sludge drops onto a perforated belt, where
gravity drainage takes place. The thickened
sludge is pressed between a series of rollers
to produce a dry cake.
Sludge is fed onto a rotating perforated drum
with an internal vacuum, which extracts liquid
phase.
Sludge feeds through a central pipe that
sprays it into a rotating bowl. Centrate
escapes out the large end of the bowl, and
the solids are removed from the tapered end
of the bowl by means of a screw conveyer.
Rotary drying, flash drying, sand bed.
Slurry enters thickener and settles into
circular tank. The sludge thickens and
compacts at the bottom of the tank, and the
sludge blanket remains to help further
concentration.
Compounds may be added to physically or
chemically bind water
17
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Table 4
Problem
Excessive
sludge
viscosity
Extreme pH
Pretreatment/Materials Handling Table: Sludges (continued).
Solution
Slurry
Neutralization
Comments
Addition of water or solvent;
addition of dispersants.
LJme, an alkaline material, is
widely used for
neutralizing acid wastes; sulfuric acid is used
to neutralize alkaline wastes
Oversized
material.
removal
disaggregation,
sorting
See Table 5
(Soils)
Table 5
Pretreatment/Materials Handling Table: Soils.
Problem
Solution
Comments
Material
transport and
excavation
Oversized
material
removal,
disaggregation,
sorting
Dragline Crane-operated excavator bucket to dredge
or scrape soil to depths and farther
reaches..
Backhoe Useful for subsurface excavation or at the
original ground level.
Heavy Includes bulldozers, excavators, and dump
earthmoving trucks for excavation and transport.
equipment
Conveyer May be useful for large-volume transport or
feed to treatment unit.
Vibrating Vibrates for screening of fine particles from
screen dry materials. There is a large capacity per
area of screen, and high efficiency. Can be
clogged by very wet material.
Static screen A wedge bar screen consists of parallel bars
that are frame-mounted. A slurry flows down
through the feed inlet and flows tangent/ally
down the surface of the screen. The curved
surfaces of the screen and the velocity of the
slurry provide a centrifugal force that
separates small particles.
Grizzlies Parallel bars that are frame-mounted at an
angle to promote materials flow and
separation. Grizzlies are used to remove a
small amount of oversized material from
predominantly fine soil.
Hammer mill Used to reduce particle size of softer
materials.
18
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Table 5
PretreatmentlMaterials Handling Table: Soils (continued).
Problem
Solution
Comments
Oversized Impact Breaks up feed particles by impact with
material crusher rotating hammers or bars. Impact crushing
removal, works best with material that has several
disaggregation, planes of weakness, such as impurities or
sorting (cont.) cracks.
Shredder Reduces size of waste material. Shredders
are available to handle most materials,
including tires, metal, scrap, wood, and
concrete.
Tumbling mill Reduces size of rock and other materials
using a rotating drum filled with balls, rod,
tubes, or pebbles.
Cyclone Separates different sized particles by
centrifugation and gravity.
Fugitive Dust Natural (e.g., water) or synthetic materials that
emissions suppressant strengthen bonds between soil particles.
Negative Vacuum system that may be used to collect
pressure air vapors and/or dust particles and prevent
system release into atmosphere.
Foam Applied to soil surface to control volatile
emissions and dust during excavation
Covered Temporary shelter with structurally or air
shelter supported cover to restrict emissions to
enclosed volume.
Dewatering Belt filter Useful for dewatering of very wet soils
press, (lagoon sediments, wetlands).
centrifuge
Rotating dryer Additional drying may permit higher feed
rates for thermal treatment systems.
19
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Table 6
Residuals Management.
Technology
Residual Generating Residual
Contaminants Potential Management
Treated Fluidized bed
soil or ash incineration, infrared
thermal treatment,
rotary kiln incineration
Treated
soil
Low-temperature
thermal stripping
Afterburner Low-temperature
ash thermal stripping
Solids
(ash)
Glass
residue
Solids
Spent
activated
carbon
Aqueous
effluent
Wet air oxidation
Vitrification
Chemical extraction
- basic extractive
sludge treatment
Low-temperature
thermal stripping, air
pollution control
device, wastewater
treatment
Metals
Metals,
nonvolatile
organics
Volatile metals
Metal oxides,
insoluble salts
Nonvolatile
metals at the
operating
temperature
Metals, trace
organics
Volatile organics
Fly ash Electrostatic precip- Volatile metals
itator, baghouse,
cyclone
Leachate Biodegradation,
stabilization/
solidification
Chemical extraction,
soil washing
Wet air oxidation
Trace metals
Trace organics
Trace organics
Carboxylic acids
and other
carbonyl group
compounds; low
molecular weight
organics, such
as acetaldehyde,
acetone,
methanol
Stabilization/solidification,
vitrification
Stabilization/solidification,
vitrification
Stabilization/solidification,
vitrification
Mechanical dewatering,
stabilization/solidification
Disposal
Stabilization/solidification,
vitrification
Incineration, thermal
regeneration, wet air
oxidation, steam strip-
ping with water treatment,
biodegradation
Stabilization/solidification,
recycle to primary
thermal unit, reuse of ash
Chemical precipitation
Stabilization/solidification
Biological treatment or
carbon adsorption,
photooxidation, chemical
oxidation
Biological treatment or
carbon adsorption
Biological treatment or
carbon adsorption,
photooxidation, chemical
oxidation
20
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Table 6
Residuals Management (continued).
Technology
Residual Generating Residual Contaminants
Potential Management
Water/ Glycolate
reagant mix dechlor/nation
Water/ Soil washing!
flushing soil flushing
agent mix
Organic
effluent
Scrubber
water
Off-gas
Solvent extraction
Incineration
(fluid/zed bed
incineration, rotary
kiln incineration,
vitrification unit,
infrared thermal
treatment), off-gas
collection and
treatment
In situ vitrification
Stabilization/
solidification
Wet air oxidation
Organics
Organics
Metals
Cyanides
Organics (non-
PCBs)
Organics mixed
with PCBs
Caustic, high
chloride content,
volatile metals,
organics, metal
particulates, and
inorganic
particulates
Trace levels of
combustion
products, volatile
metals, and/or
volatile organics
Ammonia,
volatile organics
Low molecular
weight
compounds,
such as
acetaldehyde,
acetone, acetic
acid, methanol
Distillation followed by
incineration
Distillation, carbon
adsorption, biological
treatment, chemical
oxidation, photochemical
oxidation
Chemical precipitation
Chemical oxidation, wet
air oxidation, electrolytic
oxidation, photochemical
oxidation
Recycle or reuse as fuel
Incineration
Neutralization, chemical
precipitation, reverse
osmosis, settling ponds,
evaporation ponds,
filtration, and gas phase
incineration of organics,
chemical oxidation,
photochemical oxidation
Gas scrubber, activated
carbon adsorption
Gas scrubber,
carbon adsorption
Gas scrubber, carbon
adsorption, fume
incineration, biological
treatment
21
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2.5 Examples for Using This Guide
Provided below are two examples that illustrate how to use this guide.
The first example is for soils or sludges containing a single waste group (as
defined in Table 1); the second example illustrates the use of the guide for
soils and sludges containing multiple waste groups.
2.5.1 Example for a Single Waste Group
The steps involved in using this guide for contaminated soils or sludges
containing a single waste group are as follows:
1 Perform preliminary waste characterization.
• Identify the waste matrix (soil or sludge)
• Identify contaminants of concern.
•Classify contaminants into waste groups using Table 1; if waste
contains more than one waste group, use procedure given in Section
2.5.2.
2. Consult appropriate waste/technology table (Tables 2 and 3).
• Generate a list of potential technologies.
3. Evaluate technology restriction tables, technology descriptions, and
pretreatment/materials handling tables for identified technologies.
• Refine list of potential technologies.
• Identify data collection requirements.
4. Contact EPA experts and/or vendors for further information (if
necessary).
5. Finalize list of potential technologies and data collection requirements
needed for further evaluation.
As outlined above, the initial waste characterization step identifies the
waste matrix and waste group (contaminant). The user should then consult
the appropriate waste/technology table, Table 2 for soils or Table 3 for
sludges. The next step is to find the contaminant or waste group in the left
margin, read across the table, and list those technologies identified as
having a demonstrated or potential effectiveness. Next, the technology
restriction table for each potential technology should be evaluated to
identify possible restrictive waste characteristics, process limitations, and
data collection requirements needed for further evaluation. A number of
technology restriction tables direct the user to the pretreatment/materials
handling tables, Table 4 for sludges and Table 5 for soils. These tables
contain common materials handling, processing, and pretreatment options
that may eliminate or reduce restrictive waste characteristics.
2.5.2 Example for Multiple Waste Groups
The steps involved in using this guide for contaminated soils or sludges
containing multiple waste groups are as follows:
1. Perform waste characterization.
• Identify waste matrix (soil or sludge).
• Identify contaminants of concern.
•Classify contaminants into waste groups using Table 1.
22
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2. Consult appropriate waste/technology table (Table 2 or 3) for each waste
group.
•Generate a list of potential technologies for each waste group.
3. Evaluate technology restriction tables, technology descriptions, and
pretreatment/materials handling tables for each potential technology and
waste group.
• Identify technologies (if any) that alone are capable of treating all waste
groups identified.
• Develop potential treatment trains.
•Identify data collection requirements.
4. Contact EPA experts and/or vendors for further information (if
necessary).
5. Finalize list of technologies capable of treating all waste groups
identified, list of potential treatment trains, and data collection
requirements needed for further evaluation.
As shown above, this guide can also be used to evaluate the treatability
of waste soils or sludges containing more than one type of contaminant or
waste group. When evaluating wastes with multiple waste groups, the first
step is to evaluate each waste group independently, as described above.
The next step is to compare the list of technologies identified for the
waste groups. The ideal solution would be to find one or more technologies
that have effectiveness (demonstrated or potential) on all of the waste
groups of concern. If such a technology can be identified, its technology
restriction table should be carefully evaluated against each waste group for
possible restrictive characteristics and data collection requirements.
If a single technology with demonstrated or potential effectiveness
cannot be identified, combinations of technologies or treatment trains that
can successfully treat the waste should be identified. A treatment train is
composed of two or more technologies used in series. Each technology is
included to remove or destroy a certain waste group or contaminant;
therefore, each technology needs to be effective only on its target waste
group. Technologies may be effective on one waste group but are
adversely impacted by another present in the waste. These technologies
can be used as part of a treatment train provided the interfering waste
group is treated prior to being processed by the technology. Each
technology restriction table should, therefore, be thoroughly evaluated
against each waste group to identify contaminants that must be treated
prior to application of particular technologies. This step allows the user to
develop the order of the technologies within a potential treatment train.
By reviewing the waste/technology tables, technology restriction tables,
and pretreatment tables, the user will be able to identify possible treatment
trains, the restrictive waste characteristics that can affect the trains, the data
collection requirements necessary to identify potential problems, and the
pretreatment needed to resolve various waste-handling problems. This
information, along with the referenced documentation and EPA and vendor
contacts, will make it possible for the user to initiate advanced planning for
in-depth engineering studies and/or bench-scale testing of potential
treatment technologies.
23
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-------
Section 3
Application of this Guide to a Hypothetical Waste
This section illustrates the use of this guide by describing, step-by-
step, a technology screening for a hypothetical waste. (See Figure 2.) The
first step is to perform a preliminary waste characterization as described in
Section 2.1 The waste characterization step involves identifying the
physical/chemical form or matrix of the waste (i.e., soil or sludge) and
contaminants (usually based on existing data). For this example, the waste
characterized is a soil contaminated with trichloroethylene (TCE) and lead.
These constituents were chosen for this example because they represent
commonly occurring waste groups.
The two waste groups are initially screened separately. On Table 1
(Waste Group Examples), TCE is classified as a halogenated volatile
organic and lead is classified as a volatile metal.
Table 2 identifies the following technologies as having demonstrated
effectiveness or potential effectiveness on soils contaminated with
halogenated volatiles such as TCE:
Rotary kiln incineration (demonstrated);
Fluidized bed incineration;
Infrared thermal treatment;
Vitrification;
Soil washing;
Glycolate dechlorination;
Low temperature thermal stripping;
Chemical extraction;
In situ vacuum and steam extraction;
In situ vitrification;
In situ soil flushing; and
In situ biodegradation.
According to Table 2, three technologies have demonstrated
effectiveness or potential effectiveness on soils contaminated with volatile
metals such as lead:
• Stabilization/solidification (demonstrated);
• Soil washing; and
• In situ vitrification.
Comparison of the two lists reveals two technologies that could
potentially treat both waste groups in a single step. Soil washing and in situ
vitrification are potentially effective on both waste groups.
The next step is to consult the technology summaries for both
technologies to determine restrictive waste characteristics.
So/7 Washing (Table B.3-1) - The table indicates that the formulation
of a suitable washing fluid is difficult for wastes containing mixtures of
organics (i.e., TCE) and metals (i.e., lead). The effectiveness of the
technology also appears highly dependent on the characteristics of the soil.
25
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Figure 2. Screening methodology flowchart for a hypothetical waste.
Identify Waste Matrix
(soil), Contaminants of
Concern (TCE and lead),
and Waste Groups
(halogenated volatile
organic and volatile
metal)
Generate List of
Potential Technologies
for Soils (Table 2)
Develop Treatment
Scenarios Addressing
Individual Waste Groups
Sequentially in Trains
Develop Treatment
Scenarios Addressing
Multiple Waste Groups
Concurrently
Review Technology
Summaries and Tables
for Limiting
Characteristics
Consult Pretreatment
(Table 4) and Residuals
Management (Table 5)
Screen Alternatives to
Determine Feasible
Scenarios
Identify Data Needs
and Contacts
* Refine Treatment
Alternatives
Conduct Additional Waste _j
Characterization
Finalize Treatment
Technologies to be
Considered Further
26
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This technology may not be suitable for this waste; if the lead concentration
is such that extensive quantities of washing fluid would be required or if the
soil consists of a high percentage of clay, then the soil/metal complex may
be difficult to manage effectively.
In Situ Vitrification (Table B.10-1) - The table indicates that the
capacity of the off-gas treatment system to process combustion gas limits
the concentration of combustible liquids and solids that can be treated by
the melt during an established period of time. The allowable concentration
is also depth related. Mapping the site and bench-scale testing are vital to
determine the technology's feasibility at a particular site. Lead is not
identified as a restrictive characteristic. The technology summary indicates
that the TCE will be destroyed while the lead is solidified in the resulting
glass-like mass.
From the review of the technology restriction tables, in situ vitrification
shows promise as a single technology that can effectively treat soil
contaminated with both TCE and lead. Extensive site mapping and
feasibility testing are required to determine if in situ vitrification can be
implemented at the particular site. The technology description indicates that
an off-gas will be generated by the process, requiring off-gas collection
with a hood and treatment. The residuals management table (Table 6)
indicates that the off-gas will contain combustion products, traces of TCE
(from volatilization, during startup, of organics that are located close to the
surface), and traces of volatile metals (including lead) that may be present
on-site. A gas scrubber is necessary to treat the off-gas, as
recommended by the table.
The treatment of wastes containing organics and metals would be more
difficult with soil washing than with in situ vitrification. However, in situ
vitrification is not demonstrated at commercial scale on CERCLA waste.
Furthermore, no commercial, full-scale units are available at this time.
Since the feasibility of in situ vitrification is site specific and therefore
may not apply to the site in question and since soil washing will not likely
treat the contaminated soil effectively, the next step is to identify and
evaluate each possible multistep treatment process or treatment train.
Obviously, there are many possibilities to cover; only a few possible
treatment trains will be investigated here to illustrate the screening process.
Low Temperature Thermal Stripping Followed by Stabilization/
Solidification - One possible TCE-lead treatment train is low temperature
thermal stripping of TCE followed by stabilization/solidification of the lead
compounds. Table 2 indicates that low temperature thermal stripping is
potentially effective on TCE but has little effect on lead. In addition, Table
B.6-1, the technology restriction table for low temperature thermal
stripping, indicates that the technology is not effective on metals. This
restrictive characteristic would preclude the use of this technology for
removing both contaminants; however, the low temperature thermal
stripping segment of the train is included only for TCE removal. No
restrictive characteristics are listed in Table B.6-1 for volatile organics
(TCE), although the technology's effectiveness appears highly dependent
on soil characteristics. Therefore, further evaluation of this technology
should concentrate on defining site-specific soil characteristics. Table 6
presents potential management options for spent carbon adsorption units
that may be used in the process to remove the volatile organics from the
off-gas. Thermal regeneration, incineration, and wet air oxidation are
options that must be considered as part of the treatment train for treating
the spent carbon.
27
-------
The second segment of the treatment train would involve stabilization/
solidification of the lead. The majority (if not all) of the volatile organic, TCE
in this example, would have been removed by the low temperature thermal
treatment step of the treatment train. Furthermore, this segment of the
treatment train is targeted only at lead treatment; therefore, its effectiveness
on TCE is not important if the low temperature thermal stripping has
effectively removed the TCE. If the TCE has not been effectively treated in
the thermal treatment step, however, it could interfere with the
stabilization/solidification process.
Based upon the information contained in this guide, a low temperature
thermal treatment/stabilization treatment train would appear to be potentially
feasible and warrant further investigation as part of an engineering study.
Chemical Extraction Followed by Stabilization/Solidification - Another
possible TCE-lead treatment train is chemical extraction to extract the
TCE, followed by stabilization/solidification of the lead-containing solid
residue. Table 2 shows that chemical extraction is potentially effective on
TCE but has no effect on lead. The presence of elevated levels of volatiles,
such as TCE, is identified under Table B.1-1 as impacting the extraction
process. However, Table B.1-1 further explains that an additional
separation step, such as distillation, will remove the volatiles from the
process solvent, thus eliminating any problems. The technology description
(B.I) explains that lead, insolubilized by a standard neutralization/
precipitation pretreatment step, will remain with the solids following the
chemical extraction step.
Upon examination of Table B.1-1, listed technology restrictions that
affect the process can be addressed by using pretreatment methods such
as pulverizing to reduce particle size, slurrying to allow the soil to be
pumped, adjusting pH, and selecting the appropriate solvent-to-waste
ratio. Therefore, further evaluation of this technology should concentrate on
defining site-specific soil characteristics to determine the necessary
pretreatment steps. Also, pretreatment methods or materials handling
procedures may cause fugitive emissions of TCE and must be controlled.
The second segment of the treatment train would involve stabilization/
solidification of the lead. As explained above, although TCE is not
effectively immobilized by the process, it will already have been removed
by chemical extraction. If extraction has not effectively removed the TCE,
however, it could interfere with the stabilization/solidification process. The
lead should be effectively immobilized by the stabilization step.
The TCE residue extracted from the soil may potentially be reused as a
fuel or in some other process if analysis shows the organic stream to be of
sufficient purity and quantity. The potentially feasible chemical
extraction/stabilization treatment train may be an attractive option
warranting further investigation because of its ability to produce a reusable
organic stream.
Rotary Kiln Incineration Followed by Stabilization I Solidification - Rotary
kiln incineration followed by stabilization/solidification of the resulting ash
and/or treatment of scrubber water is another possible treatment train.
Table 2 indicates that rotary kiln incineration has been demonstrated on
soils contaminated with halogenated volatiles, such as TCE. Table A.2-1
does not mention lead as affecting the rotary kiln treatment process;
however, lead air emissions may restrict the use of incineration. The
presence of restrictive characteristics identified in Table A.2-1 must be
established by determining site-specific soil characteristics to further
evaluate the usefulness of this technology at a particular site.
28
-------
The treated soil or residual ash will no longer contain TCE but will still
contain lead. The residual ash will need to be treated in the
stabilization/solidification stage of the treatment train. Considerations for
stabilization/solidification were discussed in the previous examples.
The need for residuals management for this treatment train is identified
in both the technology restriction tables and Table 6. The rotary kiln will
generate a scrubber water from its off-gas cleaning process that will be a
caustic, high chloride content waste. Since volatile metals are in the influent
to the kiln, they may appear in the scrubber water and in air emissions if
the scrubber is not sufficiently effective. The residuals management table
indicates the need for neutralization (and possibly precipitation if some lead
is carried over in the off-gas and collected in the scrubber) before the
scrubber water can be discharged. A rotary kiln/stabilization treatment train
with appropriate residuals management would appear to be potentially
feasible and warrant further investigation as part of an engineering study.
29
-------
-------
APPENDICES
31
-------
-------
Appendix A
Thermal Treatment Technologies
Introduction
Thermal treatment is a term associated with the use of high
temperatures as the principal means of destroying or detoxifying hazardous
wastes. There are several thermal processing methods; some are well-
developed and proven, and others are in the development stage. The
thermal processing modes described herein are:
• Fluidized bed incineration for soils and sludges;
• Rotary kiln incineration for soils and sludges;
• Infrared thermal treatment for soils and sludges;
• Wet air oxidation treatment for sludges;
• Pyrolytic incineration for soils and sludges; and
• Vitrification for soils and sludges.
More specific information on the applications of each thermal process is
given in the sections that follow. Low temperature thermal volatilization (i.e.,
stripping) is discussed under physical/chemical treatment in Section B.6.
The advantages of thermal treatment include:
• Volume reduction;
• Detoxification;
• Energy recovery; and
• Materials recovery.
Thermal treatment offers essentially complete destruction of the original
organic waste. The destruction and removal efficiency (ORE) achieved for
waste streams incinerated in properly operated thermal processes often
exceeds the 99.99 percent requirement for hazardous wastes. Hydrogen
chloride (HCI) emissions are also easily controlled. Furthermore, available
air pollution control technologies can effectively address the potential for
particulate emissions. This appendix contains information on individual
thermal treatment technologies. Table A-1 summarizes waste
characteristics that impact thermal treatment technologies in general. For
each specific thermal technology, a technology description is provided,
followed by an illustration of the process and a technology restriction table.
Each technology restriction table includes a listing of the characteristics
impacting the feasibility of the process, reasons for restriction, data
collection requirements, and references. The numbers in the "Reference"
column are correlated with the list of references included at the end of this
appendix.
33
-------
Table A-1
Technology Summary.
Waste Type: Soils and Sludges
Technology: High-Temperature Thermal Treatment • Genera/*
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data
Collection
Requirements
Ref.
High moisture
content
Elevated levels of
halogenated
organic
compounds
Presence of
PCBs, dioxrns
Presence of
metals
Elevated levels of
organic
phosphorus
compounds
Moisture content affects handling Analysis for 1
and feeding and has major impact percent
on process energy requirement. moisture
Halogens form HCI, HBr, or HF Quantitative 2,3,4
when thermally treated; acid gases analysis for
may attack refractory material organic Cl,
and/or impact air emissions. Br,and F
PCBs and dioxins are required to Analysis for 2,3
be incinerated at higher priority
temperatures and long residence pollutant
times. Thermal systems may require
special permits for incineration of
these wastes.
Metals (either pure or as oxides, Analysis for 2,3,4
hydroxides, or salts) that volatilize heavy metals
below 2,000''F (e.g., As, Hg, Pb,
Sn,) may vaporize during
incineration. These emissions are
difficult to remove using
conventional air pollution control
equipment. Furthermore, elements
cannot be broken down to
nonhazardous substances by any
treatment method. Therefore,
thermal treatment is not useful for
soils with heavy metals as the
primary contaminant. Additionally,
an element such as trivalent
chromium (Cr + 3) can be oxidized
to a more toxic valence state,
hexavalent chromium (Cr+6), in
combustion systems with oxidizing
atmospheres.
During combustion processes, Analysis for 2,3
organic phosphorus compounds phosphorus
may form phosphoric acid
anhydride (PzOs), which contributes
to refractory attack and slagging
problems.
Applicable to fluidized bed, infrared, rotary kiln, wet air oxidation, and
pyrolytic as well as vitrification processes.
34
-------
A.1 Fluidized Bed Incineration
Technology Description
Fluidized bed incinerators are used to incinerate halogenated and
nonhalogenated solids, sludges, slurries, and liquids in a controlled
atmosphere with surplus oxygen levels. These systems are also used to
destroy RGBs and phenolic wastes and to thermally decontaminate soils.
The .fluidized bed incinerator consists of a refractory-lined vessel
containing a bed of inert, granular, sand-like material (sized crushed
refactory). Solids, sludges, and liquids can be injected directly into the bed
or at its surface. If contaminated soil is being processed, the soil mass acts
as the bed material. In one design (Waste-Tech) the decontaminated soils
and heavy noncombustible inert material are continually withdrawn from the
bottom of the vessel. In operation, combustion air is forced upward through
the bed, which fluidizes the material at a minimum critical velocity. The
heating value of the wastes plus minimal auxiliary fuel maintains a desired
combustion temperature in the vessel. The heat of combustion is
transferred back into the bed, and the agitated mixture of waste, fuel, and
hot bed material in the presence of fluidizing air provides a combustion
environment that resists fluctuations in temperature and retention time due
to moisture, ash, or Btu content of the waste.
A secondary reaction chamber is employed to permit adequate retention
time (2 seconds plus) for combustion of volatiles. Combustion gases are
drawn out of the end of the secondary reaction chamber and treated for
removal of acid gas and particulate constituents. Process residuals are
decontaminated ash, treated combustion gases, and possibly wet scrubber
water.
Fluidized beds can be operated at lower temperatures than other
incinerators because of the high mixing energies aiding the combustion
process. This mixing offers the highest thermal efficiency while minimizing
auxiliary fuel requirements and volatile metals emissions. Fluidized bed
systems may make use of in-bed limestone addition for acid gas capture,
which removes the requirement for wet scrubbers and blowdown water
treatment.
A variation of fluidized bed incinerator, the Circulating Bed Combustor
(CBC), uses higher air velocity and circulating solids to create a larger and
highly turbulent combustion zone for the efficient destruction of toxic
chemicals and the retention of resultant acid vapors. Solids, liquids, or
sludges are burned along the height of the combustion section. Dry
limestone, added to the feed, reacts in the combustion zone and captures
acid gases without using wet scrubbers. The high turbulence, staged
combustion, and long residence time in circulating bed combustors allow
incineration of the waste at lower temperatures (1500-1600°F), thus
eliminating ash agglomeration and reducing nitrous oxide (NOX) emissions.
The entrained solids are separated from off-gases by an integral cyclone
and recycled to the combustor through a nonmechanical seal. The flue
gases are cooled in an off-gas cooler by the heating of water, steam, or
combustion air. Any remaining particulates in the cooled off-gas are
separated in a baghouse filter, and the clean off-gas stream is vented to
the atmosphere.
Status: This technology is used widely in the U.S. paper industry and on
wastes throughout Europe. A full-scale fluidized bed system has
successfully completed its Part B Permit trial burn on RCRA and other toxic
wastes. Ogden Environmental Services has constructed at least one
commercial, mobile unit, and others are planned.
35
-------
Figure A. 1-1 is a diagram of the fluidized bed incineration process,
Figure A.1-2 is a diagram of a circulating bed combustor, and Table A.1-
1 is a technology restriction table.
EPA Contacts:
Donald Oberacker, (513) 569-7341, FTS 684-7341
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Joseph McSorley, (919) 541-2920, FTS 629-2920
U.S. Environmental Protection Agency
Air and Energy Engineering Research Laboratory
Research Triangle Park, NC 27711
Vendors:
Harold Diot, (619) 455-2383
Ogden Environmental Services, Inc. (CBC)
10955 John Jay Hopkins Dr.
San Diego, CA92121
Wayne L. Shipman, P.E., (303) 279-9712
Waste-Tech Services, Inc.
18400 West 10th Avenue
Golden, CO 80401
Minesh Kinkhabwala, (201) 922-2323
C-E Environmental
Combustion Engineering, Inc.
7 Becker Farm Rd.
Roseland, NJ 07068
36
-------
Figure A. 1-1. Fluidized bed incineration.
CO
-•j
F
Solid Haw 1 |n|et A
FMdm 1 Heceivmg.anK
1 Solids Feeder ^
Liquid Fuel *
Atomizer
om i
tmosphere '
Fluidized
Bed
^1 1 » %v.\«.>t 1 .-
l:::t.-ifjt.-l
|rv?/nt:u/|*_
To
Atmosphere
Particulate T
, Rfimoual 1
i
-M_^
Combustion 1
Air T
. \ *
Heat
Exchanger
» y
Preheated
Combustion Air Solld
l__ : 1 wast
— 1 1
Bed Material
Supply
4
s to
e Disposal
Spent Bed Material
and Ash
Source: Figure 2.2. EPA/540/2-86/003(f)
-------
Figure A.1-2 Circulating bed combustor.
Combustor
Forced Draft
Fan
Stack
Ash Conveyor
Cooling Water System
V
Source: Ogden Environmental Services
38
-------
Table A.1-1 Technology Summary.
Waste Type: Soils ana Sludges
Technology: Fluidized Bed Incineration'
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data
Collection
Requirements
Ref.
Feed particle size
Low-melting
point (less than
1600°F)
constituents,
particularly alkali
metal salts and
halogens (e.g., Na,
Cl compounds)
Ash content
Waste density
Presence of
chlorinated or
sulfonated wastes
Large particle size affects feeding Size, form,
and removal of solids from the bed. quantity of
Solids greater than 1 inch (2.5 cm) solid material;
must be reduced in size by size reduction
shredding, crushing, or grinding. engineering
(Note Waste-Tech fluid bed data: soil
systems can handle up to 3-m particle size
feed.) Fine particles (clays, silts) distribution;
result in high paniculate loading in USGS soil
flue gases. classification
Defluidization of the bed may occur Ash fusion
at high temperatures when particles temperature
begin to melt and become sticky.
Melting point reduction (eutectics)
may also occur. Alkali metal salts
greater than 5% (dry weight) and
halogen greater than 8% (dry
weight) contribute to such
refractory attack, defluidization, and
slagging problems.
Ash contents greater than 64% can Ash content
foul the bed. (Note: Waste-Tech's
continuous bed letdown, screening,
and rejection minimize th/s type of
problem.)
As waste density increases Waste-bed
significantly, particle size must be density
decreased for intimate mixing and comparison
heat transfer to occur.
These vvasfes require the addition Analysis for
of sorbents such as lime or sodium priority
carbonate into the bed to absorb pollutants
acidic gases or the addition of a
flue gas scrubbing system as part
of the treatment train.
1,2,3,
4
2,4
See also Table A-1, High-Temperature Thermal Treatment (General).
39
-------
A.2 Rotary Kiln Incineration
Technology Description
Rotary kiln incinerators are slightly inclined, refractory-lined cylinders.
Their primary use is the combustion of organic solids and sludges,
including SARA, RCRA, and other contaminated wastes. Rotary kiln
incineration involves the controlled combustion of organic wastes under net
oxidizing conditions (i.e., the final oxygen concentration is significantly
greater than zero).
Wastes and auxiliary fuel are injected into the high end of the kiln and
passed through the combustion zone as the kiln slowly rotates. Rotation of
the combustion chamber creates turbulence and improves the degree of
burnout of the solids. Retention time can vary from several minutes to an
hour or more. Wastes are substantially oxidized to gases and inert ash
within this zone. Ash is removed at the lower end of the kiln. Flue gases are
passed through a secondary combustion chamber and then through air
pollution control units for particulate and acid gas removal.
Although organic solids combustion is the primary use of rotary kiln
incinerators, liquid and gaseous organic wastes can also be handled by
injection into either the feed end of the kiln or the secondary combustion
chamber. Wastes having high inorganic salt content (e.g., sodium sulfate)
are not recommended for incineration in this manner because of the
potential for degradation of the refractory and slagging of the ash. Similarly,
the combustion of wastes with high toxic metal content can result in
elevated emissions of toxic air pollutants, which are difficult to collect with
conventional air pollution control equipment.
Residuals generated from this process are (1) ash from the low end of
the kiln and in some cases from air pollution control devices such as
hydrocyclones, (2) stack gases, and (3) brine solution from the ash quench
and wet scrubber. More information on residuals management is included in
Table 6.
Status: Rotary kiln incinerators, both fixed and mobile, are widely
available commercially from many vendors and are in broad use for most
hazardous waste applications, including RCRA, CERCLA, and other toxic
substances.
Figure A.2-1 illustrates rotary kiln incineration, and Table A.2-1 is a
technology restriction table.
EPA Contact:
Frank Freestone, (201) 321-6632, FTS 340-6639
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Edison, NJ 08837
Vendor
No specific names of vendors are listed here
because the technology is widely available.
40
-------
Figure A.2-1. Rotary kiln incineration.
Solid Waste
Shredder
Rotary Kiln
Solids Feed Rate
1-6 Tons/Hour Waste < " >
Ash Conveyor
Ash
Bin
Raw Water
n
^
Air
F .1
Fuel Tfc[
Waste
Burner
Secondary
Combustor
_». To Ejector System
-*• To Brine Concentrator
-*• To Deaerator
Stack
Neutralizer'
Source: ENSCO Environmental Services
I
Ash Brine
- Solution
Concentrator
Concentrated
Brine Solution
-------
Table A.2-1 Technology Summary.
Waste Type:
Technology:
Soils and Sludges
Rotary Kiln Incineration1
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data
Collection
Requirements Ref.
Oversized debris
such as large
rocks, tree roots,
and steel drums
Difficult to handle and feed; may
cause refractory loss through
abrasion. Size reduction equipment
such as shredders must be
provided to reduce solid particle
size."
Size, form,
quantity of
oversized
debris. Size
reduction
engineering
data
2,3,4
Volatile metals
(Hg, Pb, Cd, Zn,
Ag. Sn)
Alkali metal salts,
particularly
sodium and
potassium sulfate
(NaSO* KSQ4)
Fine particle size
of soil feeds such
as clay, silts
Spherical or
cylindrical wastes
Ash fusion
temperature of
waste
Heating value of
waste
May result in high metals
concentration in flue gas, thus
requiring further treatment.
Cause refractory attack and
slagging at high temperatures.
Slagging can impede solids
removal from the kiln.
Results in high particulate loading
in flue gases due to the turbulence
in the rotary kiln.
Such wastes may roll through the
kiln before complete combustion
can occur.
Soil and
stack gas
analysis for
subject
metals
Percent Na, K 2,4
Soil particle
size
distribution,
USGS~ soil
classification
Physical
inspection of
the waste
Operation of the kiln at or near the Ash fusion
waste ash fusion temperature can temperature
cause melting and agglomeration of
inorganic salts.
Auxiliary fuel is normally required to
incinerate wastes with a heating
value of less than 8,000 Btu.
Btu content
1,4
See a/so Table A-1, High Temperature Thermal Treatment (General).
See Tables 4 and 5.
U.S. Geological Survey.
42
-------
A.3 Infrared Thermal Treatment
Technology Description
Infrared thermal units use silicon carbide elements to generate thermal
radiation beyond the red end of the visible spectrum. Materials to be
treated pass through the unit on a belt and are exposed to the radiation.
Off-gases pass into a secondary chamber for further infrared irradiation
and increased retention time. Flue gases are treated based on feed
constituents and are emitted, as are ash and any scrubber effluents.
The infrared thermal treatment unit originally developed by Shirco
Infrared Systems has a feed system and an infrared primary chamber with
a continuous waste conveyor. From the primary chamber, combustion
products flow into a secondary chamber, which can be either a combination
gas-fired/infrared unit or a conventional secondary chamber. Flue gas
treatment is accomplished by any conventional off-gas cleanup system.
Infrared energy, or thermal radiation of wavelengths outside the visible light
spectrum at the red end, is generated by silicon carbide resistance heating
elements. The significant difference between an infrared unit and a rotary
kiln is that the primary units (i.e., kiln or infrared) differs; the other parts of
the systems are similar.
The primary process variables in the infrared system are temperature,
residence time, waste material layer thickness on the conveyor belt, and
combustion air flow. In the incineration mode, nominal operating
temperatures are 1400°F and 1600°F in the primary and secondary
chambers, respectively. In the pyrolysis mode, temperatures can be as low
as 800°F. Optimum material thickness is 2 inches for throughput.
Temperature and residence time are inversely related; residence times can
vary from 5 to 50 minutes. Combustion air flow rate is adjusted to control
combustion efficiency.
The residuals from this process, like those of other thermal treatment
processes, are ash, scrubber water, and off-gases. The gases are
scrubbed to remove acid components and particulates. Table 6 contains
further information on residuals management.
Status: This technology has been used recently for the treatment of
CERCLA wastes containing halogenated and nonhalogenated organics,
including RGBs.
Figure A.3-1 illustrates infrared thermal treatment, and Table A.3-1 is
a technology restriction table.
EPA Contact:
Howard Wall, (513) 569-7691, FTS 684-7691
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendors:
Scott Berdine, (214) 404-7540
Ecova Corporation
Park Central IX
12790 Merit Drive
Dallas, TX 75251
(Ecova Corporation has acquired a license to use the Shirco technology)
43
-------
Saul Furstein, (404) 981-9332
Westinghouse Haztech, Incorporated
5280 Panola Industrial Blvd.
Decatur, GA 30035-4013
Samuel Insalaco, (419) 423-3526
OH Materials Corporation
P.O. Box 551
Findley, OH 45839
John Peterson, (503) 286-4656
Reidel Environmental Services
P.O. Box 507
Portland, OR 97205
44
-------
Figure A.3-1. Infrared thermal treatment.
Material Processing/De-Watering
n
Air Pollution Control
Equipment
Secondary Combustion
Chamber
Material
Holding
Feed Metering
Ash Disposal
H
IL
^^
if'
j'
8
V
>»
3 «^rra ~~ «^zr:a
^_£.
f 1 L
JL Jc~
Primary Combustion
Ash Discharge
_jj
Chamber
Source: Shirco Infrared System*, Inc.
-------
Table A.3-1 Technology Summary.
Waste Type: Soils and Sludges
Technology: Infrared Thermal Treatment"
Characteristics
Impacting Process
Feasibility
Nonhomogeneous
feed size
Reason for Potential Impact
Nonuniform feed size requires
pretreatment before feeding and
conveyance through the system.
The largest solid particle size
processible is 1 to 2 inches Debris
such as rocks, roots, and
containers must be crushed or
shredded to allow for feeding."
Data
Collection
Requirements
Size, form,
quantity of
solid material;
size reduction
engineering
data
Ref
3
Moisture content Since waste material is conveyed
through the system on a metal
conveyor belt, soils and sludges
must be firm enough (usually
>22% solids) to allow for proper
conveyance Soils and sludges with
excess water content (e.g., lagoon
sediments) require dewatering prior
to feeding."
Moisture
analysis
See a/so Table A-1, High Temperature Thermal Treatment (General).
See Tables 4 and 5.
46
-------
A.4 Wet Air Oxidation
Technology Description
Wet air oxidation is a thermal treatment technology that breaks down
suspended and dissolved oxidizable inorganic and organic materials by
oxidation in a high-temperature, high-pressure, aqueous environment.
Wet air oxidation is used primarily to treat biological wastewater treatment
sludges. It has, however, potential application to concentrated liquid or
sludge waste streams containing organic and oxidizable inorganic wastes
(including halogenated organics, inorganic/organic cyanide, and phenols in
inorganic/organic sludges) that are not readily biodegradable. It can also be
used to regenerate powdered activated carbon.
In this process, waste is mixed with compressed air. The waste-air
mixture passes through a heat exchanger and then into the reactor, where
oxygen in the air reacts with oxidizable material in the waste. In the heat
exchanger, the raw waste and air mixture is heated to reaction conditions
by indirect heat exchange with the hot oxidized effluent. The reaction is
exothermic, and the heat liberated further raises the temperature of the
reaction mixture to the design temperature. In cases in which the heat of
reaction is insufficient to maintain the design operating temperature
(because of a low influent concentration of oxidizable organics), additional
heat may be necessary. This extra heat is added either by injecting startup
steam into the reactor or by placing a startup heat exchanger before the
reactor and after the feed heat exchanger. The exit stream from the reactor
is passed through the heat exchanger, heating the incoming material. A
separator is then used to separate the resultant gas stream from the
oxidized liquid stream.
With halogenated organics, it may be necessary to use a catalyzed wet
oxidation process. The major impact of a catalyst on the system is either to
lower the reaction temperature or to increase the destruction efficiency.
The environmental impact of the gas, liquid, and solid effluent must be
addressed when considering wet air oxidation for hazardous waste
treatment. The oxidation products from treating toxic organic compounds
are not entirely carbon dioxide and water. Some low molecular weight
compounds, such as acetaldehyde, acetone, acetic acid, and methanol, are
also formed. These compounds are distributed between the off-gas and
oxidized liquid phase. Volatile organic components in the process off-gas
can be controlled by a variety of technologies including scrubbing
techniques, carbon adsorption, and fume incineration. The liquid effluent,
containing predominantly carboxylic acids and other carbonyl group
compounds, are readily treated by biological treatment or a combination of
biological treatment and carbon adsorption. The liquid effluent will contain
suspended solids, which are insoluble ash containing metal oxides and
other insoluble salts such as sulfates, phosphates, and silicates. The
insoluble ash can usually be dewatered and disposed of. See Table 6 for
more detail on residuals treatment.
Modar has a technology that operates in the supercritical state of water
(above 647 K and 22.1 MPa). Data indicate that faster reaction rates and
higher efficiencies are obtained because gases, including oxygen, and
organic substances are completely soluble in supercritical water.
Status: A pilot-scale Supercritical Water Oxidation Unit (by Modar) has
been successfully demonstrated on RCRA wastes, including PCBs
(Reference 6).
47
-------
Figure A 4-1 illustrates wet air oxidation, Figure A.4-2 illustrates a
Supercritical Water Oxidation Unit, and Table A.4-1 is a technology
restriction table.
EPA Contact:
Harry M. Freeman, (513) 569-7529, FTS 684-7529
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendors:
William Copa, (715) 359-7211
Zimpro, Incorporated
Military Road
Rothschild, Wl 54474
Fran Ferraro, (303) 452-8800
VerTech Treatment Systems
Westminster, CO 80234
KC. Swallow, Ph D., or Bill Killilea, (617) 655-7741
Modar, Incorporated
14 Tech Circle
Natick, MA 01760
48
-------
Figure A.4-1 Wet air oxidation.
_ Oxidizable
Waste
Feed
Pump
Process
Heat
Exchanger
Air
Compressor
Reactor
Off-Gas
to
Off-Gas Treatment
System
Separator
Source: Zimpro. Inc.
To Wastewater
Treatment
49
-------
Figure A.4-2. Supercritical water oxidation unit.
Heater
01
o
Hydrogen from
Common Storage
Compressor
Urine
&
Feces
.jV
A,
,i
te Water ^ ll •. ^j
centrate {I.) Slurry
Grinder RurnP
Oxygen from
Common Storage
• i> r"">
Fluid
Drawoff
1st
Rea
f ^
^J
Stag
ctor
/
\ So
Dr.
e
2nd-Stage
Reactor
ids
awoff
c*\-
To CO2
Removal
Subsystem
LPVL
Separator
Ion Exchange
Polishing
Source: Modar, Inc.
-------
Table A.4-1 Technology Summary.
Waste Type: Sludges
Technology: Wet Air Oxidation
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data Collection
Requirements
Ref.
Solids content
Viscosity of sludge
COD < 100,000 mg/l
COD > 200,000 mg/l
Soluble metals
Volatile organics
Abrasive and/or
acidic
characteristics
Fluoride content
<0.1 g/l for stainless
steel and titanium;
chloride content
< 20 g/l for titanium
and < 1 g/l for
stainless steel*
pH < 1 and > 12 for
titanium or pH < 5
and >12 for
stainless steel
Calcium and
magnesium content
less than 0.1 g/l
Solids should not unduly foul heat
transfer surfaces.
The waste must be in a pumpable
liquid or liquid-like form, with a
viscosity of less than 10,000 SSU.
Wastes with COD concentrations
outside this range are either too
dilute or too concentrated for a
feasible application.
Soluble metals, for the most part,
will remain in the liquid effluent
after treatment. See pretreatment
and res/duals treatment tables.
Volatiles may be stripped from the
aqueous phase before being
oxidized. Requires off-gas
treatment. See residuals treatment
table
Wastes that have high abrasive
and/or acidic characteristics may
require more expensive
equipment and materials (e.g.,
titanium).
Corrosion of reactor.
Corrosion of reactor. See
pretreatment table.
Can cause fouling of heat transfer
surfaces.
Physical
inspection
Viscosity, total
solids analysis,
suspended
solids analysis
Analysis for
heavy metals
Analysis for
volatile
organics
Treatability
testing
Analysis for
total halides
pH analysis
Analysis for
calcium and
magnesium
2,3
2,3
COD analysis 2,3
2,3
2,3
Data based on pilot-scale units. Higher limits are expected upon upscaling
to field units.
" Information supplied by Modar, Inc.
51
-------
A. 5 Pyrolytic Incineration
Technology Description
Pyrolysis involves the destruction of organic material in the absence of
oxygen at a high temperature to reduce toxic organic constituents to
elemental gas and water. The absence of oxygen allows separation of the
waste into an organic fraction (gas) and an inorganic fraction (salts, metals,
particulates) as char material. The process conditions range from pure
heating (thermolysis) to conditions in which only slightly less than the
theoretical (stoichiometric) air quantity is supplied. Gases are the principle
product generated by the pyrolytic reaction, although ash can also be
generated.
The pyrolytic incineration process marketed by Midland Ross
Corporation is a two-step process. In the first step, waste material is
decomposed at 1000 to 1400°F into an organic gaseous fraction and an
inorganic solid fraction in the absence of air, or oxygen. In the second step,
the organic fraction is fed into a high-temperature, direct-fired incinerator
operated at 2200°F, where hazardous elements from the organic fraction
are destroyed and the clean, decontaminated gases are sent to an energy
recovery device. This system is capable of handling drummed liquids,
solids, or sludges with heating values ranging from 0 to 20,000 Btu/lb. For
noncontainerized wastes or sludges, a continuous pyrolytic system is
recommended.
Status: This technology is commercially available and used at the RCRA
facilities; however, its application to CERCLA wastes has not been
demonstrated commercially.
Figure A.5-1 illustrates a pyrolytic incineration system, and Table A.5-
1 is a technology restriction table.
EPA Contact:
Ivars J. Licis, (513) 569-7718, FTS 684-7718
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendor:
Val Daiga, (419) 537-6125
Surface Combustion Division
Midland Ross Corporation
P.O. Box 907
Toledo, OH 4369-0907
52
-------
Figure A.5-1 Pyrolytic incineration system.
Carbottom Furnace
01
CO
ch Fume Reactor r-
id Dwell Chamber
J
V
Exhaust Stack
? Z *]
Source: Midland Ross Corp.
-------
Table A.5-1 Technology Summary.
Waste Type: Soils and Sludges
Technology: Pyrolytic Incineration'
Characteristics
Impacting Process
Feasibility
High Btu organic
waste
Temperature
Reason for Potential Impact
Desirable since energy recovery is
the ultimate goal.
First chamber requires temperature
lower than 1400°F to capture
gaseous organics.
Data
Collection
Requirements
gas analysis
temperature
monitoring
Ref
-
See also Table A-1, High Temperature
generic incineration restrictions.
Information provided by vendor.
Thermal Treatment (General) for
54
-------
A. 6 Vitrification
Technology Description
Vitrification thermal treatment is used to transform chemical and physical
characteristics of hazardous waste such that the treated residues contain
hazardous material immobilized in a vitrous mass. The destruction of the
hazardous waste is achieved in a reaction chamber in which high
temperature is used to reduce toxic organic compounds to elemental gas
(CO, H2> and carbon. Inorganic contaminants should remain entrained in
the glass and siliceous melts The advantages of vitrification over other
thermal processes are the lack of oxidation products and large air
emissions and the reduced leachability of inorganic materials, such as
heavy metals.
The reaction chamber is divided into upper and lower sections, both of
which are refractory-lined and have separate electric (480-volt, 3-phase)
heating systems. The upper section accepts the waste feed via gravity and
contains gases and other products of pyrolysis; the lower section contains
the two-layer molten zone for the melts of the metal and siliceous
components of the waste
For solid waste treatment, the feed-limited to 4 inches-is gravity
fed on a conveyer into the reactor. The wastes are destroyed at a nominal
temperature of 3002°F or 1650°C ( + /- 104°F or 40°C). The off-gas and
particulates are drawn off by an induction fan and treated through a
cyclone, a baghouse, and an acid gas scrubber. Solid waste is withdrawn
from the lower section of the chamber via separate molten glass and metal
taps Both particulate and gas streams can be recycled to the reactor.
The residue streams from the vitrification unit are molten glass, molten
metal, scrubber water, and off-gas The concentrations of hazardous
constituents in the residuals are such that further treatment is not required.
More detail on these residuals is provided m Table 6.
The Westinghouse electric pyrolyzer is a pyrolytic thermal process
developed for the destruction of hazardous waste solids, such as
contaminated soils and sludges, with concentrations of organics and water
up to 10 percent and 25 percent, respectively The process involves the
destruction of organic material in the absence of oxygen.
Another vitrification process, promoted by Vitrifix of North America, is
presently demonstrated for rendering asbestos nontoxic by thermal
decomposition. The vitrifix furnace temperature is maintained above
1300°C. If the temperature falls toward 1100°C, the resulting glass
becomes increasingly viscous. In this system, asbestos is thermally
decomposed at temperature below 900°C. Thus a temperature safety
margin of 200°C prevents unconverted asbestos from leaving the furnace.
The product of the process is silicate glass, dark green to black in color.
The Vitrifix furnace unit is a transportable system that comes in three
different sizes up to 2 tonnes/day, 2-10 tonnes/day, and >10 tonnes/day.
This method is presently used commercially in the United Kingdom to
destroy asbestos-containing soils, including debris, and to treat low-level
radioactive waste. A 2-tonne per day unit has been used under the
supervision of EPA to destroy asbestos-containing soils with feed size less
than 1 inch. The transportable system is not currently available in this
country commercially. Vitrifix is also developing the technology for
application to heavy metals in soils and fly ash. Metals such as Fe*2, Cr,
Ni, and Hg are a problem, and incorporation of an additional process step is
required.
55
-------
A third vitrification technology, marketed by Retech as a centrifugal
reactor, offers indirect heating of solid and liquid organic wastes via electric
conductance from a plasma torch. A high temperature of 2,800°F is
achieved, and at this temperature liquid components of the waste are
volatilized, reducing the organic constituents to carbon monoxide,
hydrogen, and hydrochloric acid, and, in some cases, reducing all the way
to carbon dioxide and water. The volatilized components are captured and
are treated in a gas scrubber unit. Metals and small amounts of solid
carbon remain in the vitrified combustion residue. If the residue analysis
indicates that hazardous organic constituents remain in the residue, then it
is recycled and treated again in the reactor. The vendor claims that the
volume of the waste is reduced by a factor of 20. This technology can be
used to treat a sludge or soil contaminated with PCBs or another high-
solids content waste.
Status: A commercial Westinghouse prototype was tested on Superfund
wastes in September 1986; the process is expected to be commercially
available in 1989. Vitrifix has demonstrated a small-scale commercial plant
on asbestos waste and is constructing a fixed, full-scale commercial
facility for asbestos-containing materials. Retech has a prototype unit not
yet demonstrated on RCRA or CERCLA waste.
Figures A.6-1 and A.6-2 illustrate vitrification systems, and Table
A.6-1 is a technology restriction table.
EPA Confacf:
Ivars J. Licis, (513) 569-7718, FTS 684-7718
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendors:
William H. Reed, (412) 722-5303
Westinghouse Electric Corporation
Environmental Technology Division
Box 286
Madison, PA 15663-0286
David Roberts, (703) 684-1090
Vitrifix North America
1321 Duke Street, Suite 304
Alexandria, VA 22314
John Pariola, (707) 462-6522
Retech, Incorporated
P.O. Box 997
100 Henry Station Road
Ukiah, CA 95482
56
-------
Figure A.6-1. Vitrification ("electric pyrolyzer").
Water
Surrogates
Feed
»
,
Rotary
Valve
0.
"*
|
Stack
Off-Gas - r"\ *
r
Pyrolyzer
Feed Reaction
Conveyor Chamber
1
1 4T ,-LT f-JT^
f Induction
1 a, 0) « 0,
1 Gas c ~ r " n «
* Bellows -J3 ^
-------
Figure A. 6-2. Vitrification ("pyrolytic centrifugal reactor").
Plasma Torch
Sealed Chamber Provides
Total Control of Atmosphere
Afterburner
Offgas Treatment System
Centrifugal
Reactor
(8ft dia
Source: Retech, Inc.
-------
Table A.6-1 Technology Summary.
Waste Type: Soils and Sludges
Technology: Vitrification
Characteristics
Impacting
Process
Feasibility
Feed
compatibility
(particle size)
Maintainability
and reliability
Reason for Potential Impact
Large particle size undesirable.
Size reduction is required,
nominally to 4 inches.
Full-scale units need to be
operated in the field to demonstrate
technology effectiveness.
Data
Collection
Requirements
Particle size
distribution
Field
operating data
Ref.
*
*
Gas emissions
Monitoring for PICs and metals
emission and to demonstrate ORE.
Moisture content
Organic content
Metals
Particulate air
emission
Maximum of 25% water by weight.
Organic content limited to 10%.
Presence of mercury and cadmium
undesirable
Particulate air emissions required
to be captured in gas scrubbing
system
Hydrogen
concentration,
oxygen
concentration,
organics and
inorganics
concentrations
Analysis
moisture
Analysis for
total organic
content
Analysis for
metals
Monitoring for
air emissions
Information supplied by Westinghouse.
Information supplied by Retech.
59
-------
References
(1) Niessen, Walter R. 1978. Combustion and incineration processes. New
York, N.Y.: Marcel Dekker, Inc.
(2) USEPA. 1986. U.S. Environmental Protection Agency, Office of Solid
Waste and Emergency Response. Mobile treatment technologies for
Superfund wastes. #540/2-86/003(f). Washington, D.C.: U.S.
Environmental Protection Agency.
(3) USEPA. 1986. U.S. Environmental Protection Agency, Office of Solid
Waste and Emergency Response. Superfund treatment technologies: a
vendor inventory. #540/2-86/004. Washington, D.C.: U.S.
Environmental Protection Agency.
(4) Versar Inc. 1985. Assessment of treatment technologies for hazardous
waste and their restrictive waste characteristics. Vol. 1A-D.
Washington, D.C.: U.S. Environmental Protection Agency, Office of
Solid Waste.
(5) Versar Inc. 1986. Assessment of technological options for management
of hazardous wastes: chemical monographs for the First Third P and U
waste codes. Vol. 1. Washington, D.C.: U.S. Environmental Protection
Agency, Office of Solid Waste.
(6) Staszak, C.N., Malinowski, K.C., and Killilea, W.R. The pilot-scale
demonstration of the MODAR oxidation process for the destruction of
hazardous organic waste materials. Environmental Progress. Vol. 6, No.
1 (February 1987).39 ff.
60
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, Appendix B
Physical/Chemical Treatment Technologies
Introduction
This appendix describes the applications and restrictions of
physical/chemical treatment technologies for the cleanup of hazardous
waste sites. These treatment technologies are widely used in industrial
waste treatment and pretreatment. Thus, more complete descriptions of the
processes can be found in the literature.
Physical treatment processes separate the waste stream by either
applying physical force or changing the physical form of the waste, while
chemical treatment processes alter the chemical structure of the
constituents to produce a waste residue that is less hazardous than the
original waste. Further, the altered constituents may be easier to remove
from the waste stream. The physical/chemical treatment processes
presented in this appendix are:
Chemical extraction;
In situ decontamination;
Soil washing;
In situ soil flushing;
Glycolate dechlorination;
Low temperature thermal stripping;
In situ vacuum and steam extraction;
Stabilization/solidification;
Chemical reduction-oxidation; and
In situ vitrification.
As discussed under many of the other treatment technologies, physical
treatment processes will also produce residuals that must be disposed of in
an environmentally safe manner. Treatment sludges may require additional
treatment either on site or off site prior to disposal Treatment needed may
include dewatering (and subsequent treatment of wastewater) and
immobilization.
The further treatment required for concentrated solids and sludges will
depend on the type and level of contamination. A number of thermal,
physical, chemical, and immobilization processes may be used as
treatment alternatives. Liquids will also require further treatment if
hazardous constituents, such as volatile organics, are present.
Treatment sludges from any of these processes may require additional
treatment either on site or off site prior to disposal. Treatment needed may
include dewatering (and subsequent treatment of water) and immobilization.
Depending upon the applicable requirements, solid residuals can be
disposed of on site or off site.
This appendix contains information on individual physical/chemical
treatment technologies. For each technology, a technology description is
provided, followed by an illustration of the process and a technology
restriction table. Each technology restriction table includes a listing of the
61
-------
characteristics impacting the feasibility of the process, reasons for
restriction, data collection requirements, and references. The numbers in
the "Reference" column are correlated with the list of references included
at the end of this appendix.
62
-------
B.1 Chemical Extraction
Technology Description
The chemical extraction processes are used to separate contaminated
sludges and soils into their respective phase fractions: organics, water, and
particulate solids. One demonstrated process, Basic Extraction Sludge
Treatment (BEST), developed by Resources Conservation Company, has
been used primarily to treat oily sludges containing hydrocarbons and other
high-molecular weight organics. This process has not been used to treat
soils. Another process that is available to treat aqueous waste and sludges
is known as solvent extraction with liquified gas.
In the BEST process, a secondary or tertiary amine (usually
triethylamine, TEA) solvent is mixed at cool temperatures with soils or
sludges. Depending on the waste matrix, waste may need slurrying, which
is achieved as part of the treatment train. At the low temperature the solvent
is simultaneously miscible with oil and water. The solvent extracts organics
adsorbed on the particles. The resulting mixture is centrifuged or filtered to
separate the oil-extracted solids from the liquid phase. The solids are
dried to recover the solvent for recycle within the system.
The particulate-free solvent/oil/water solution is heated, breaking any
emulsions present and separating the organic and aqueous fractions by
reducing their mutual solubility The heated two-phase solution is
decanted. The top fraction leaving the decanter is primarily solvent and oil,
which are sent to a stripping column where solvent is recovered and oil is
discharged. Some volatile organics, such as acetone, toluene, or methyl
ethyl ketone, may boil off with the amine, requiring an additional selective
distillation step. The bottom fraction, predominantly water, is sent to another
stripping column to remove residual solvent. The contaminated oil is further
treated, if necessary.
The waste, whether sludge or soil, commonly requires pretreatment
before solvent addition. It may be necessary to add water or solvent to the
waste so that it becomes pumpable. The process requires alkaline
conditions, generally a pH of 10, so that TEA can exist. Alkaline conditions
are created by a front-end neutralization step in which caustic soda is
added to the feed stream to raise the pH. This step has the added
advantage of insolubilizing any heavy metals existing in the aqueous phase.
TEA is a weak base that can also be used to raise the pH of the feed
stream by forming triethylammonium salts; however, this option is not
usually cost effective. See Table 5 for more details concerning pretreatment
options.
The BEST process produces an aqueous effluent stream, dry solids,
waste oil, and solvent. The solvent is recycled back to the treatment
system. The aqueous effluent may require biological treatment or carbon
adsorption to remove residual organics before final discharge. If soluble
metals are present in concentrations above allowable discharge limits,
chemical precipitation will also be needed. The recovered waste oil should
be analyzed to determine suitability for recycle or reuse as fuel. If neither
option is viable, the waste oil must be incinerated. The residual solids are
essentially free of mobile organics. Extraction tests should be conducted on
the residual solids to determine the need for stabilization before their final
disposal. See Table 6 for further details concerning residuals treatment
options.
Critical fluid solvent extraction with liquified gas technology has been
developed by CF Systems Corporation. Liquified gases (carbon dioxide and
63
-------
propane) at high pressure are used to extract oils and organic solvents from
wastewater and sludge in a continuous process. The evaporated gases are
recycled following recompression. This technology is similar to supercritical
fluid extraction.
CF Systems has operated a small-scale unit to extract dissolved and
emulsified organics from aqueous waste. A small-scale sludge deoiling
unit is available and has been used for the extraction of heavy oil from
sludge. The material must be pumpable. The ideal pressure is 250 psi for
propane and 950 psi for carbon dioxide and ambient temperature for
extraction of organics. In order to use this technology for solids or soils
treatment, the material must be slurried so that it can be pumped into the
unit.
Using this technology, aqueous-based oily sludges or PCB-
contaminated surface impoundment sludges can be treated. Materials that
are primarily contaminated with heavy metals or inorganic compounds are
not appropriate for this technology.
Status: A 100-ton per day BEST unit has been successfully used at a
CERCLA cleanup site to treat PCB-contaminated oily sludge. CF Systems
plans to demonstrate the small-scale sludge deoiling unit on PCB-
contaminated sediments in 1988.
Figure B.1-1 illustrates chemical extraction, and Table B.1-1 is a
technology restriction table.
EPA Confacf:
Edward Bates, (513) 569-7774, FTS 684-7774
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendors:
Paul McGough, (206) 828-2400
Resources Conservation Company
3101 N.E. Northup Way
Bellevue, WA 98004
Thomas Cody, (617) 890-1200
CF Systems Corporation
140 Second Avenue
Waltham, MA 02154-1100
64
-------
CD
Figure B.1-1. Chemical extraction ("BEST").
Raw Waste
r
I Frontend
I Neutralization I
I I
—i Power I ' I
I »' I I '
I Steam I I •
• m> • I
ling vvdiei i i
_»J I
rumentation Air I
_ - ^— - _ _—— — — ^ I
Site Specific
Source Resources Conservation Company
-------
Figure B.1-2. Critical fluid solvent extraction.
Compressor
Recycled Solvents
Solvents and Organics
Solvent
Feed
Solids
Source: CF Systems, Corporation
66
-------
Table B.1'1 Technology Summary.
Waste Type:
Technology:
Soils and Sludges
Chemical Extraction
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data
Collection
Requirements
Ref.
Presence of
elevated levels of
volatiles
Particle size
greater than 114
inch
pH
Presence of high
amounts of
emulsifiers
Metals (e.g.,
aluminum) or
other compounds
that undergo
strong reactions
under highly
alkaline conditions
Types of waste
Volatiles may combine with process Volatile
solvent, requiring an additional organic
separation step. analysis
Equipment used in process not
capable of handling large particle
size. (See pretreatment table for
size reduction techniques.) Waste
must be pumpable.
TEA (used in BEST process) is
weak base and will exist in solvent
form only at approximately pH &10.
Wastes with lower pH must be
pretreated to raise pH. See
pretreatment table.
Adversely impact oil/water phase
separation. A greater quantity of
solvent is required for appropriate
treatment
Strong reactions may occur during
treatment process because of
caustic addition. The adverse
reaction may be avoided by using
TEA for pH adjustment.
Materials contaminated with heavy
metals not suitable. Wastes that are
reactive with carbon dioxide and
propane must be pretreated. ***
Wastes containing >200 ppm
organics and oil concentration up
to 40 percent are acceptable.
Particle size
distribution
pH
measurement
Glassware
process
simulation to
measure
phase
separation
characteristics
Analysis for
aluminum
Metals
analysis
Information supplied by Resources Conservation Co.
Information supplied by CF Systems Corp.
See Tables 4 and 5.
67
-------
B.2 In Situ Chemical Treatment
Technology Description
In situ chemical treatment allows treatment of contaminated soils and
waste deposits in place. By using this treatment method a wide range of
treatment agents, including solvents, precipitating and neutralizing
chemicals, and stabilizing agents, can be delivered directly to the waste
source. These treatment agents can be used to treat many types of
contaminants, including petroleum hydrocarbons, chlorinated hydrocarbons,
metals, PCBs, and radionuclides.
In situ soil decontamination using a wide variety of chemicals is
marketed by Toxic Treatment (USA), Inc. under the trade name Detoxifier.
The Detoxifier is a mobile treatment unit capable of neutralization or pH
adjustment by the addition of acids or bases; destruction or chemical
modification of contaminants via the use of oxidizing or reduction
chemicals; and solidification/stabilization by the addition of chemicals or
physical agents. Other applications include the addition of nutrients,
microorganisms, and oxygen to promote in situ biodegradation and air or
steam stripping of volatile contaminants.
The Detoxifier unit consists of a process tower, a control unit, and a
process treatment train. These components are custom designed and
configured to meet site-specific requirements. The process tower
accomplishes the drilling and dispenses the remediation agents. The
process tower is capable of penetrating the soil/waste medium to depths of
more than 30 feet. Remediation agents (in dry, liquid, vapor or slurry form)
are added to and mixed with the soil/waste at various depths during the
upward and/or downward movements of the drill head assembly. A
rectangular shroud, under vacuum, covers the drill head assembly to isolate
the treatment area and prevent any environmental release. On-line
analytical instruments continuously monitor the treatment conditions. The
remediation of a large area is affected by a block-by-block treatment,
approximately 30 square feet per block.
Another technology using a combination of direct delivery system and
drilling is a deep soil mixing (DSM) system developed by Geo-Con
Corporation. The system consists of a set of crane-supported leads which
guide a series of mixing paddles and augers, hydraulically driven. As the
ground is penetrated, stabilizing agents or other fluids are fed through the
center of each shaft. The auger flights break the soil loose and lift it to the
mixing paddles, which blend the additives with the soil. The augers are
positioned to overlap each other and form a continuous block. As the
augers advance to a greater depth, the soil and agent are remixed by
additional mixing paddles on each shaft. When the desired depth is
reached, the augers are withdrawn, and the mixing process is repeated on
the way to the surface. Each auger is 36 inches in diameter, and there are
four shafts together on 27-inch centers. The four shafts treat
approximately three square yards of area per stroke. Each shaft is supplied
with 40,000 foot pounds of torque. The DSM system can be used in almost
any soil type; however, the more fines in the soil, the more mixing is
required. The system can be used below the water table, and very soft rock
formations can be drilled and mixed. Large obstructions such as buried
concrete blocks, boulders, or pilings, must be avoided, but rocks less than
one foot in diameter can be mixed. Objects such as drums, trash, and
bottles may be broken up and penetrated.
Potential applications for in situ remediation in general include treatment
of metals and radionuclides (mining mill tailings) by neutralization,
68
-------
precipitation, and solidification/stabilization; and treatment of hydrocarbons,
metals, and radionuclides by oxidation/reduction.
Sfafus: Toxic Treatment's process is commercially available and has been
demonstrated successfully on RCRA sites but has not been used at
Superfund sites to date. A demonstration is scheduled to occur in late 1988
in California at a State Superfund site. Solidification/stabilization using the
Geo-Con/DSM system has been demonstrated on PCB-contaminated
soils.
Figure B.2-1 is a process diagram for Toxic Treatment's in situ
chemical treatment system. Table B.2-1 is a technology restriction table.
EPA Contacts:
Mary Stinson, (201) 321-6683 FTS 340-6683
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Edison, NJ 08837
Paul dePercin, (513) 569-7797
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendors:
Michael Ridosh, (415) 572-2994
Toxic Treatment (USA) Incorporated
901 Mariner's Island Blvd. Suite 315
San Mateo, CA 94404
Brian Jasperse, (412) 856-7700
Geo-Con, Incorporated
P.O. Box 17380
Pittsburgh, PA 15235
69
-------
Figure B.2-1. In situ chemical treatment ("Detoxifier").
Steam
Makeup
Water
Tank
Compressor
Shroud
Water
ator
'P
Scrubbing
System
Cyc
Den-
Cooling
System
one
uster
3-Stage
Activated
Carbon
Polishing
System
\
Reheat
System
Cryogenic
Conden-
sation
System
Recovered Hydrocarbons
Source: Toxic Treatment (USA) Inc.
Spent Carbon
•™^»-
To Regeneration
Recovered
—»-
Hydro-
carbons
-------
Table B.2-1 Technology Summary.
Waste Type: Soils and Sludges
Technology: In Situ Chemical Treatment
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data
Collection
Requirements Ref.
Site Site must be level and flat with few Topography
characteristics underground obstructions. assessment
Type of soil Sandy loam soil preferred to clay; Soil analysis
fines require more mixing.
* Information supplied by Toxic Treatments (USA), Inc..
71
-------
B.3 Soil Washing
Technology Description
The soil washing process extracts contaminants from sludge or soil
matrices using a liquid medium such as water as the washing solution. This
process can be used on excavated soils that are fed into a washing unit.
The washing fluid may be composed of water, organic solvents,
water/chelating agents, water/surfactants, acids, or bases, depending on the
contaminant to be removed. In contrast, in situ soil washing is performed on
unexcavated soils and consists of injecting a solvent or surfactant solution
to enhance the contaminant solubility, resulting in increased recovery of
contaminants in the leachate or ground water (see B.4).
EPA's mobile extraction system uses water as the washing fluid.
Contaminated soil enters the system through a feeder, where oversized
nonsoil materials and debris that cannot be treated are removed with a
coarse screen. The waste passes into a soil scrubber, where it is sprayed
with washing fluid. Soil particles greater than 2 mm in diameter are sorted
and rinsed, leave the scrubber, and are dewatered. The remaining soil
enters a countercurrent chemical extractor, where additional washing fluid is
passed countercurrent to the soil flow, removing the contaminants. The
treated solids are then dewatered. The remainder of the process is a
multistep treatment for removal of contaminants from the washing fluid prior
to its recycling. Treatment is generally accomplished by conventional
wastewater treatment systems depending on the type of contamination. See
Table 6 for residuals management techniques.
A soil washing process developed by MTA Remedial Resources, Inc.
(MTARRI) utilizes technology transfers from both the mining and enhanced
oil recovery fields to simultaneously remove and concentrate the organic
contaminants from soils. Release of contaminants from clay and sand is
accomplished through alkaline and surfactant addition, which results in
changing the interfacial tension. The treatment residues, detoxified soil, can
be returned to the site and the treatment byproducts, concentrated
organics, require either incineration, landfilling, or additional treatment for
ultimate contaminant removal. This technology has been also demonstrated
to remove metallic compounds of lead, cadmium, chromium, copper, and
nickel. This technology is commercially available. Restoration of aquifers
contaminated with aromatic, aliphatic, and/or organo-chlorides is
accomplished using alkaline agents, surfactants, and biodegradable
polysaccharides. The vendor claims that 5 tons of treatment residue is
generated per 100 tons of soil treated.
Status: Two mobile units are commercially available. This technology is
currently used at Department of Defense sites as a modified air stripper to
treat volatiles. Two mobile units will be operational by the end of 1988.
Figures B.3-1 and B.3-2 illustrate soil washing systems, and Table
B.3-1 is a technology restriction table.
EPA Contact:
Richard Traver, (201) 321-6677, FTS 340-6677
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Edison, NJ 08837
72
-------
Vendors:
Paul B. Trost, (303) 279-4255
MTA Remedial Resources, Inc.
1511 Washington Avenue
Golden, CO 80401
Al Bourquin, (206) 883-1900
Ecova Corporation
3820 159th Avenue NE
Redmond, WA 98052
73
-------
Figure B.3-1. Soil washing system.
Contaminated Soil
Feeder
Rough
Screen
Oversize
Non-Soil
Materials
and Debris
f
+2mm Scrubbed Soil
Clean Air
Discharge
t
Air Cleaner
Exhaust
from Hood
Drum Screen
Water Knife
Soil Scrubber
t r
Recycled
Stripper Spray
Makeup
Water
-2mm
Soil
Slurry
Skimmings
to Disposal
Exhaust
from Hood
Counter-Current
Chemical
Extractor
Clean
Rinse
Spent
Washing
Fluids
Clanfier
Filter
Backwash
-2mm
Scrubbed
Soil
Dewatering
Device
Clarified
Washing Fluids
H Washing Fluid Recycler
~\
^ Fines to
Disposal
Spent
Carbon
Source: EPA
-------
Figure B.3-2. Soil washing.
Water Bleed
When Necessary
Sized Contaminated
Soil
n
oo
Reagents
3
^^^ /
^^s
1
Flocculant
r
4
Reactor
Flotation Cells
Plate and
Frame Filter
Surge Tank
Continuous Plate
and Frame Filter
Clean
Dewatered Soil
Source: MTARRI
-------
Table B.3-1 Technology Summary.
Waste Type: Soils
Technology: Soil Washing
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data
Collection
Requirements Ref.
Unfavorable
separation
coefficient for
contaminant
Complex mixtures
of waste types
(e.g., metals with
organics)
Variation in waste
composition
Unfavorable soil
characteristics:
• High humic
content
• Soil, solvent
reactions
• Fine particle size
(silt and clay)
• Clay soil
containing
semivolatiles
Unfavorable
washing fluid
characteristics:
Excessive volumes of leaching
medium required.
Formulation of suitable washing
fluids difficult.
May require frequent reformulation
of washing fluid.
Equilibrium 1
partition
coefficient
Analysis for
priority
pollutants,
solubility data
Statistical
sampling,
analysis for
priority
pollutants
Inhibition of desorption.
May reduce contaminant mobility.
Fine particles difficult to remove
from washing fluid.
Low recovery rate because
organics are held more tenaciously.
Analysis for
organic matter
Pilot testing
Soil particle
size
distribution,
USGS soil
classification
1,2,
3,4
1,2
• Difficult recovery
of solvent or
surfactant
• Poor treatability
of washing fluid
• Reduction of soil
permeability
• High toxicity of
washing fluid
High cost if recovery low.
Requires replacement of washing
fluid.
Surfactant adheres to soil to
reduce effective porosity.
Soil may require additional
treatment for detoxification. Fluid
processing requires caution.
Bench-scale
testing
Bech -scale
testing,
conventional
analysis*
Permeability
pilot testing
Toxicity of
washing fluid
1
1
1
2
' Conventional analysis should include organic content (e.g., BOD, COD, TOC),
solids content, iron, manganese, and leachate pH.
*" Information supplied by MTARRI.
76
-------
B.4 In Situ Soil Flushing
Technology Description
In situ soil flushing, an active system, is a process applied to
unexcavated soils using a ground water extraction/reinjection system. In situ
soil flushing consists of injecting a solvent or surfactant solution (or water)
to enhance the contaminant solubility, which results in increased recovery
of contaminants in the leachate or ground water. The system includes
extraction wells drilled in the contaminated soils zone, reinjection wells
upgradient of the contaminated area, and a wastewater treatment system.
The technology is often used for removal of volatile organics from
permeable soils. More aggressive flushing involves ponds or sprinklers over
the contaminated zone to accelerate migration of contaminants. The
migration of contaminants into ground water must be prevented by
incorporating proper control measures. Sandy soils may result in
uncontrolled migration, and the inclusion of a clay-confining layer would
be a desirable measure to control migration.
The technology includes extraction and treatment systems for
contaminated ground water. Following treatment, the ground water is
reinjected upgradient of the extraction wells and leaches through the
contaminated soils. The leachate is then collected, treated, and re-injected
back into the system, creating a closed loop system. Nontoxic or
biodegradable surfactants or chelating agents may be added to the ground
water prior to reinjection. The contaminated ground water is treated using
various common wastewater techniques depending on the contaminant
being removed. If surfactants or chelating agents that pose risks of
additional contamination are added, they also must be removed for
complete remediation. See Table 6 for further information on residuals
management.
In situ soil flushing is both innovative and contaminant-specific. It has
the greatest potential for success on soils contaminated with only a few
specific chemicals. For soils and sludges that are contaminated with a
variety of hazardous materials, the effectiveness is limited, and
pretreatment or posttreatment may be necessary.
Status: Full-scale mobile units are currently available. This technology
has been selected to decontaminate a CERCLA site, and the work will
begin in 1988.
Figure B.4-1 illustrates in situ soil flushing, and Table B.4-1 is a
technology restriction table.
EPA Contact:
Richard Traver, (201) 321-6677 FTS 340-6677
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Edison, NJ 08837
Vendor:
Paul B. Trost, (303) 279-4255
MTA Remedial Resources, Inc.
1511 Washington Avenue
Golden, CO 80401
Al Bourquin, (206) 883-1900
Ecova Corporation
3820 159th Avenue NE
Redmond, WA 98052
77
-------
Figure B.4-1 In situ soil flushing.
Contaminant
Treatment &
Removal
Re-Injection of
Treated
Groundwater
Contaminant
Original
Water Table
Source EPA/540/2-86/003(f)
78
-------
Table B.4-1 Technology Summary.
Waste Type: Soils
Technology: In Situ Soil Flushing
Characteristics
Impacting Process
Feasibility
Unfavorable
separation
coefficient for
contaminant
Complex mixtures
of waste types
(e g., metals with
organics)
Variation in waste
composition
Unfavorable soil
characteristics:
• Variable soil
conditions
• High organic
content
• Low permeability
(high clay and/or
sl/t content)
• Soil, solvent
reactions
Unfavorable site
hydrology
Unfavorable
flushing fluid
characteristics:
• High toxicity or
volatility
• Difficult recovery
of surfactant
• Poor treatability
of flushing fluid
• Reduction of soil
permeability
Reason for Potential Impact
Excessive volumes of
surfactants required.
Formulation of suitable
flushing fluids difficult
May require frequent
reformulation of flushing fluid
Inconsistent flushing
Inhibition of desorption.
Reduces percolation.
May reduce contaminant
mobility.
Ground-water flow must
permit recapture of flushed
contaminants and. in some
cases, soil-flushing fluids.
Health risks.
High cost if recovery low.
Requires replacement of
flushing fluid.
Surfactant adheres to soil to
reduce effective porosity.
Data Collection
Requirements
Equilibrium partition
coefficient
Analysis for priority
pollutants, elemental
analysis
Statistical sampling,
analyses for priority
pollutants
Soil mapping
Analysis for organic
matter
Percolation test
Pilot testing
Site hydrogeology
must be well
defined
Surfactant
characterization
Bench-scale
testing
Bench-scale
testing, conventional
analysis'
Permeability pilot
testing
Ref.
1
2
2
1,2
1,2,
3,4
2,3
1,2
1,2
1,2
1
1
1
Conventional analysis should include organic content (e.g., BOD, COD, TOC),
solids content, iron, manganese, and leachate pH.
79
-------
B.5 Glycolate Dechlorination
Technology Description
Potassium polyethylene glycolate (KPEG) dechlorination is an innovative
process used to dehalogenate certain classes of chlorinated organics in
contaminated organic liquids, sludges, and soils. For example, KPEG is
used on waste oils containing dioxins and diesel fuel containing RGBs,
dioxins, and chlorobenzenes, to convert them into lower toxicity, water-
soluble materials. The KPEG solution reacts with the chlorinated organic
and displaces a chlorine molecule. This technology, developed by General
Electric, uses glycol reagent and has been demonstrated to destroy PCBs
in contaminated soil to levels required by the regulation. The contaminated
soils contained PCB in the range of <10 to 70/2 ppm, and the
contamination was reduced to meet the regulatory standard in between
1.25 and 6.25 hours.
The process involves mixing equal portions of contaminated soil and
KPEG reactants in a heated reactor. The slurry is then heated and mixed
while the reaction occurs. The reaction time can range from 0.5 hour to up
to 5 hours, depending on the type and concentration of the contaminants
and the amount of dechlorination desired. The excess reagent is then
decanted and the soil is washed two to three times with water to remove
excess reagent and the products of the reaction. The decontaminated soil is
then removed from the reactor. The decanted reagent and washes can be
recycled to treat additional soil.
In the alkaline polyethylene glycolate (APEG) process developed by
Galson Research Corporation, the reaction can be catalyzed by dimethyl
sulfoxide (DMSO). The DMSO increases the rate of the reaction by
increasing the alkalinity (i.e., strength) of the KPEG. The DMSO also aids in
the extraction of the contaminant from the soil, thereby providing for better
mixing of the reactants. The reagent and rinse waters are recycled.
Although KPEG reduces the toxicity of the waste, it increases the volume
of waste that must be further treated as wastewater. Wastewaters
containing reaction materials similar to those created as a residual by the
KPEG process are commonly treated by chemical oxidation,
biodegradation, carbon adsorption, or incineration. See Table 6 for further
information on residuals treatment.
Status: A bench-scale unit was tested on PCB-contaminated soil
during August 1987, a pilot-scale unit was tested in late 1987, and a full-
scale unit is expected to be operational in 1988.
Figure B.5-1 illustrates the glycolate dechlorination process, and Table
B.5-1 is a technology restriction table.
EPA Contact:
Charles J. Rogers, (513) 569-7757 FTS 684-7757
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendor:
Robert Peterson, Edwina Milicic, (315) 432-0506
Galson Research Corporation (APEG Process)
6601 Kirkville Road
E. Syracuse, NY 13057
80
-------
Figure B.5-1. Glycolate dechlorination.
oo
Waste to Treatment
I
and Volatiles
i k
^"
Makeup Wate
Recycle V
I
Vater
___
Soils aprt ^ Mix <-fe Docant fc First Wash
L A.
t
REAGENT
^
Reag
Rec
i
r Wash V
' Rec
entto
ycle
r
Vater to
ycle
^ Second Wash
f--->
1— ^ Clean
i Soil
~"~
Wash Water to
Recycle
Source: Galson Research Corp.
-------
Table B.S-1 Technology Summary.
Waste Type: Soils and Sludges
Technology: Glycolate Dechlorlnatlon
Characteristics
Impacting Process
Feasibility
Elevated
concentrations of
chlorinated
organics
Presence of:
* Aliphatic
organics
• Inorganics
• Metals
High moisture
content (>20%)
Reason for Potential Impact
Concentrations greater than 5%
require excessive volumes of
reagent. (Low ppm is optimum.)
Reagent effective only with aromatic
halides (PCBs, dioxms,
chlorophenols, chlorobenzenes).
Water may require excessive
volumes of reagent
Data
Collection
Requirements
Analysis for
priority
pollutants
Analysis for
priority
pollutants
Soil moisture
content
Ref.
5
5
5
LowpH(<2)
Process operates under highly
alkaline conditions.
pH testing
Presence of other Aluminum and possibly other metals Metals
alkaline reactive that react under highly alkaline analysis
onditions may increase amount of
reagent required by competing for
the KPEG. The reaction may also
produce hydrogen gas.
High humic Increases reaction time. Clay and Organic
content in soil sandy soils as well as high organic content in soil
content soils can be treated with
increased reaction time.
' Information supplied by vendor.
82
-------
B.6 Low Temperature Thermal Stripping
Technology Description
Ore design for a low temperature thermal stripping system processes
contaminated soils through a pug mill or rotary drum system equipped with
heat transfer surfaces. An induced airflow conveys the desorbed volatile
organic/air mixture through a carbon adsorption unit or combustion
afterburner for the destruction of the organics. The airstream is then
discharged through a stack. These types of systems generally may be
used to remove volatile organic compounds (Henry's Law constant >3.0 x
10-3 atm-rrr3/mole) from soils or similar solids. Process residuals are
processed soil, ash from the afterburner or spent carbon, and stack gases.
Chemical Waste Management has developed a mobile thermal desorption
system called X*TRAXtm. This system employs a process in which solids
with organic contamination are heated in the presence of water, driving off
the water and organic contaminants and producing a dry solid containing
trace amounts of the organic residue. The X*TRAX system consists of a
dryer and an off-gas handling trailer. The dryer is a rotary kiln indirectly
fired with propane as fuel. The contaminated solids or sludges are fed by
auger or pump into the dryer and heated to 500-800°F. An inert nitrogen
carrier gas transports the volatilized water and organics to the off-gas
handling system, a three-stage cooling and condensing train which
condenses organics of low, intermediate and high volatility in a stepwise
fashion. The carrier gas is reheated and recirculated into the dryer. A small
portion of carrier gas passes through a filter and a carbon adsorption drum
before being vented to the atmosphere. The relatively low temperature
heating in the presence of nitrogen prevents undesirable oxidation
reactions.
The XTRAX system is designed to treat solids or sludges containing
organics with boiling points less than about 800°F, less than 10% total
organics, and less than 60% moisture. For wastes that with higher organic
or moisture levels, an economic evaluation is conducted to determine if the
process is cost effective. Solid feeds must be screened to less than 1.25
inches in size, and for pumpable sludges, solids less than 0.4 inches must
be removed.
Status: A pilot system constructed of off-the-shelf components has
been tested on soils on at least one CERCLA site. The Chemical Waste
Management System is to be tested on mixed hazardous and radioactive
waste and PCB-contaminated soils in late 1988 and 1989.
Figure B.6-1 illustrates low temperature thermal stripping, and Table
B.6-1 is a technology restriction table.
EPA Contact:
Robert Thurnau, (513) 569-7692, FTS 684-7692
Paul dePercin (513) 569-7797, FTS 684-7797
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendor:
Raja Venkateswar, (312) 841-8360
Chemical Waste Management, Incorporated
150 West 137th Street
Riverdale, IL 60627
83
-------
Figure 8.6-7 Low temperature thermal stripping.
Air to
Atmosphere
Hot Oil
Reservoir
Air Containing
Stripped VOCs
Source: U.S. Army Toxic and Hazardous Materials Agency. Aberdeen Proving Ground
84
-------
Table B.B-1 Technology Summary.
Waste Type: Soils and Sludges
Technology: Low Temperature Thermal Stripping
Characteristics
Impacting Process
Feasibility Reason for Potential Impact
Presence of: Some process effective only for
• Metals highly volatile organics (Henry's Law
• Inorganics Constant >3 x 10~3 atm-m3/
• Less volatile mole). X'TRAX system can treat
organics organics with boiling points up to
about 800°F
Data
Collection
Requirements
Analysis for
priority
pollutants
Ref.
2,"
pH <5, >11 Corrosive effect on system
components
pH analysis
Presence of
mercury (Hg)
Unfavorable soil
characteristics:
• High percent of
clay or silt
• Tightly
aggregated soil
or hardpan
• Rocky soil or
glacial till
• High moisture
content
Boiling point of mercury (356° C)
close to operating temperature for
process (100 to 300° C).
Fugitive dust emissions during
handling."
Incomplete devolatilization during
heating.
Rock fragments interfere with
processing.
High energy input required.
Dewatenng may be required as
pretreatment."
Analysis for
mercury
Grain size
analysis
Soil sampling
and mapping
Soil mapping
Soil moisture
content
2
6
6
6
6
See Table 5.
Information supplied by vendor
85
-------
B.7 In Situ Vacuum and Steam Extraction
Technology Description
In situ vacuum extraction is a technology used to remove volatile
(Henry's Law constant >3 x 10'3 atm-m/mole) organic compounds
(VOCs) from soils. The basic components include production wells,
monitoring wells, and high-vacuum pumps. The vacuum pumps are
connected via a pipe system to a series of production wells. The production
wells are drilled through the contaminated soil zone to just above the
ground-water table. Spacing of the production wells is determined by
mathematical models or pilot testing. Monitoring wells are drilled around the
production wells to monitor the interstitial air pressure.
The system operates by applying a vacuum through the production
wells. Once the wells are tightly sealed at the soil surface, a vacuum is
created by the vacuum pumps. The vacuum is controlled by bleeding air
into the system. Because of the pressure gradient created by the vacuum
pumps, volatiles in the soil percolate and diffuse through the air spaces
between the soil particles to the production wells. The vacuum established
in the soil continuously draws VOC-contaminated air from the soil pores
and draws fresh air from the soil surface down into the soil. The removed
volatiles are processed through a liquid-vapor separator. The VOC vapors
are then treated by an activated carbon bed, catalytic converter, or
afterburner or are dispersed into the atmosphere. The liquid (VOC-
contaminated ground water) is treated in a vacuum-assisted, fully
enclosed aeration unit, which causes the VOCs to volatilize. The now
gaseous VOCs are treated as above, and the ground water is discharged or
reinjected into the ground. In most applications, the quantity of VOC-
contaminated ground water extracted will be minimal. In areas with a high
ground-water table, the VOC-contaminated air and ground water are
removed simultaneously through the production wells without the need for
additional pumps.
A similar system involves a series of air injection and air extraction wells.
Fresh air is forced down the injection wells and VOC-contaminated air is
withdrawn through the extraction wells. The removed VOC-contaminated
air is then treated in a carbon adsorption unit.
Another technology, marketed under the trade name Detoxifier by Toxic
Treatment (USA), Inc., uses a combination of drilling rig process tower,
treatment agent, and delivery tool to remove petroleum and chlorinated
hydrocarbons by steam stripping. The treatment system that has been
demonstrated to treat volatile organics consists of two hollow blades that
inject steam and hot air into the soil to a depth of almost 30 feet. The
mixture heats the soil and raises the temperature of the chemicals,
eventually causing them to evaporate. The evaporated chemicals are then
trapped at the surface in a metal box and piped to a processor, which cools
the chemical vapors until they turn into liquid. The liquid chemicals are
taken to an incinerator. A technology known as the Geo-Con/DSM System
can also be used to accomplish steam stripping of volatile organics (see
B.2).
Status: Full-scale mobile units for vacuum and steam extraction are
currently available and have been demonstrated on CERCLA wastes.
Forced air injection units are currently being tested at pilot scale.
Figure B.7-1 illustrates in situ vacuum extraction, and Table B.7-1 is a
technology restriction table. Figure B.2-1 is a process diagram that also
applies to in situ steam extraction.
86
-------
EPA Contact-
Mary Stinson, (201) 321-6683, FTS 340-6683
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Edison, NJ 08837
Paul DePercin, (513) 569-7797, FTS 684-7797
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendors:
Jim Malot, (809) 723-9171
Terra Vac, Inc.
P.O. Box 1591
San Juan, PR 00903
Brian Jasperse, (412) 856-7700
Geo-Con Inc.
P.O.Box 17380
Pittsburgh, PA 15235
Michael Ridosh, (415) 572-2994
Toxic Treatment (USA) Inc.
901 Mariner's Island Blvd., Suite 315
San Mateo, CA 94404
Al Bourquin, (206) 883-1900
Ecova Corporation
3820 159th Avenue NE
Redmond, WA 98052
87
-------
Figure B.7-1. In situ vacuum extract/on.
To Atmosphere
Vacuum Pump
f
V
Ir
i/loni
Veil
[I
toring
[I Mr
b
_ LJ.
] ^^
s-\
~
( 1
/A1
Carbon
Adsorption
1 1
Liquid/Vapor
Separator
^•^ Collected
Vapors
_
tf V
*••£
^y
^5=^
*J ^iT-li
Recover
Tank
*
Water
or
RemjecK
Production
Well
Source COM
-------
Table B.7-1 Technology Summary.
Waste Type: Soils
Technology: In Situ Vacuum and Steam Extraction
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data
Collection
Requirements Ref.
Presence of:
• Less volatile
organics
• Metals
• Cyanides
• Inorganics
High solubility of
volatile organics in
water
Only volatile compounds with a
Henry's Law constant of
approximately >3 x 1Q-3 atm-
m-/mole can be effectively
removed by vacuum extraction;
theoretically, steam or hot air
extraction should apply to less
volatile compounds.
Dissolved organics are more
mobile and harder to remove from
aqueous phase.
Analysis for
priority
pollutants,
Henry's Law
constant or
vapor
pressures for
organics
Contaminant
solubilities
8
B
Unfavorable soil
characteristics:
• Low permeability
• Variable soil
conditions
• High humic
content
• High moisture
content
Hinders movement of air through
soil matrix.
Inconsistent removal rates.
Inhibition of volatilization.
Hinders movement of air through
soil.
Percolation
test, pilot
vapor
extraction
tests
Soil mapping
Analysis for
organic matter
Analysis of soil
moisture
content
89
-------
B.8 Stabilization/Solidification
Technology Description
Stabilization, also known as solidification or fixation, technology is
applicable to solid, liquid, or sludge waste. Stabilization can be performed
in situ or in tanks or containers. In situ stabilization is achieved by a deep
soil mixing technique. In situ stabilization allows direct application of
stabilizing agents, utilizing mixing paddles and augers that blend the soil
with a stabilizing agent fed through the center of each shaft. At the end of
the treatment, a treated block of soil or a continuous stabilized mass is left
behind. Two in situ technologies marketed currently include Detoxifier and
the Geo-Con/DSM System (see B.2).
Whether in ground or above ground in tanks, stabilization facilitates a
chemical or physical reduction of the mobility of hazardous constituents.
Organic oily wastes, sludges, and contaminated soil containing nonvolatile
organics such as PCBs and creosote, and incinerator ash containing heavy
metals may be treated successfully. Mobility is reduced through the binding
of hazardous constituents into a solid mass with low permeability that
resists leaching. The actual mechanism of binding, which depends on the
type of stabilization process, can be categorized by the primary stabilizing
agent used: cement-based, pozzolanic- or silicate-based,
thermoplastic-based, or organic polymer-based. Techniques may overlap
because additives, such as silicates, are frequently used in conjunction with
the stabilizing agent to control curing rate or to enhance properties of the
solid product.
On a commercial basis, organophilic proprietary compounds-based,
asphalt-based, cement-based, and pozzolanic-based techniques have
been more successful for treating hazardous wastes than the other
techniques because of their wider range of applicability and less expensive
reagents. Thus, the major focus of this discussion is on cement-based and
pozzolanic-based techniques.
Stabilization technologies have been most widely successful when
applied to inorganic waste streams. Before stabilization, the waste slurry or
sludge may be pretreated to adjust pH and msolubilize heavy metals,
thereby reducing their mobility. The high alkalinity of most cements and
setting agents will serve to neutralize acidic leachate, keeping heavy metals
in their insoluble, less mobile form.
Data suggest that silicates used with lime, cement, or other setting
agents can stabilize a wider range of materials than cement-based
technologies, including oily sludges and sludges and soils contaminated
with solvents. Several vendors use organophilic proprietary compounds as
additives to bind organics to the solid matrix. Both the cement-based and
pozzolanic-based methods have been applied to radioactive wastes as
well. The presence of solid organics such as plastics, resins, and tars often
increases the durability of the solid end product.
The equipment used for container or tank stabilization is similar to the
one used for cement mixing and handling. It includes a feed system, mixing
vessels, and a curing area. Stabilization is applicable to many waste
streams and waste matrices as well as contaminated soil because the
mixing and handling techniques employed are very adaptive. Stabilization
can be accomplished in situ using a lagoon or mixing pit. The existing
lagoon may serve as mixing vessel, curing area, and final disposal site; or
waste may be transferred to a mixing pit, which then serves as a curing
area and possibly as a final disposal site. These techniques involve the use
of common construction machinery such as a backhoe, pull shovel, or
90
-------
front-end loader to mix the waste and reagents. Pumps can be used to
transfer light sludge wastes to the mixing pits and pumpable uncured
wastes to the curing site.
Critical parameters in stabilization treatment include selection of
stabilizing agents and other additives, the waste-to-additive ratio, mixing,
and curing conditions. All of these parameters are dependent on the
chemical and physical characteristics of the waste. Bench-scale
treatability tests should be conducted to select the proper additives and
their ratios and to determine the curing time required to set the waste
adequately. Leaching tests and compressive strength tests should be
conducted to determine the integrity of the solid end product.
The short-term environmental impact of stabilizing most amenable
wastes is small, but long-term reliability is not well known. Leachate that
may be produced as a result of the curing process should be collected and
analyzed to determine the necessity for treatment before disposal. The
volume of leachate is usually minimal. Gas monitoring, collection, and
treatment may be necessary with wastes containing ammonium ions or
volatile organics. The alkalinity of cement drives off ammonium ion as
ammonia gas. The heat generated by the curing or setting of the stabilized
product can drive off organic volatiles. See Table 6 for further detail
concerning residuals treatment.
Status: This technology has been commercially available for the
treatment of RCRA and CERCLA wastes prior to landfilling. In situ
stabilization has been used to treat CERCLA waste.
Figure B.8-1 illustrates stabilization/solidification, and Table B.8-1 is a
technology restriction table. Figure B.2-1 illustrates the in-situ delivery
technique.
EPA Contact:
Carlton Wiles, (513) 569-7795 FTS 684-7795
Edward Barth (513) 569-7669 FTS 684-7669
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendor:
This technology is readily available through numerous vendors.
91
-------
Figure B.8-1 Stabilizationlsoliaitication.
Liquid Chemical
Feed Pump
Waste
Feed
Pump
To Disposal
or Curing
Area
Source: EPA
92
-------
Table B.8-1 Technology Summary.
Waste Type: Soils and Sludges
Technology: Stabilization/Solidification
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data
Collection
Requirements
Ref.
Organic content
should be no
greater than 20-
45% by weight
when using
cement-based
technologies
Semivolatile
organics
> 10,000 ppm
PAHs
> 10,000 ppm
Wastes with less
than 15% solids
Oil and grease
should be 3,000 ppm
Organics interfere with bonding of
waste materials.
Organics interfere with bonding of
waste materials
Large volumes of cement or other
reagents required, greatly
increasing the volume and weight
of the end product. Waste may
require reconstitution with water to
prepare waste/reagent mix.
Weaken bonds between waste
particles and cement by coating the
particles.
Insoluble material passing through
a No. 200 mesh sieve can delay
setting and curing Small particles
can also coat larger particles,
weakening bonds between particles
and cement or other reagents.
Particle size >1/4 inch in diameter
not suitable.
May retard setting easily leached
Reduce physical strength of final
product; cause large variations in
setting time; reduce dimensional
stability of the cured matrix, thereby
increasing leachability potential.
Cyanides interfere with bonding of
waste materials
Analysis for
volatile
solids, total
organic
carbon
Analysis for
semivolatile
organics,
PAHs
Analysis for
total solids
and
suspended
solids
Analysis for
oil and
grease
Soil particle
size
distribution
Analysis
for.total
halides
Analysis for
inorganic
salts
Analysis for
cyanides
2,10
2,10
* Information provided by vendors marketing this technology.
93
-------
Table B.8-1 Technology Summary (continued).
Waste Type: Soils and Sludges
Technology: Stabilization/Solidific ation
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data
Collection
Requirements Ref.
Sodium arsenate,
borates,
phosphates,
iodates, sulfide,
and
carbohydrates
Sulfates
Volatile organics
Presence of
teachable metals
Phenol
concentration
greater than 5%
Presence of coal
or lignite
Retard setting and curing and
weaken strength of final product.
Retard setting and cause swelling
and spallmg.
Volatiles not effectively immobilized.
Driven off by heat of reaction.
Sludges containing volatile organics
can be treated using a heated
extruder/evaporator to evaporate
free water and VOCs and mixing
with asphalt. VOCs with flashpoint
below 350° F, thermally unstable
materials, solvents in sufficient
concentrations to soften the
asphalt, and highly reactive
materials require pretreatment.
Effectiveness of stabilization
methods may vary.
Results in marked decreases in
compressive strength.
Coals and lignite can cause
problems with setting, curing, and
strength of the end product.
Bench-scale
testing
Analysis for
sulfate
Analysis for
volatile
organics,
bench-scale
testing
Analysis for
priority
pollutants,
bench-scale
testing
Analysis for
phenols
Core
sampling with
specific
analysis for
coal.
2,10
2,6
10
5,9
* Information provided by vendors marketing this technology.
94
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B.9 Chemical Reduction-Oxidation
Technology Description
The chemical reduction-oxidation (redox) process is employed to
destroy hazardous components or convert the hazardous components of
the waste stream to less hazardous forms. Redox processes are based on
reduction-oxidation reactions between the waste components and added
reactants in which the oxidation state of one reactant is raised while that of
another is lowered.
A significant use of chemical redox is the reduction of hexavalent
chromium (Cr+6) to tnvaient chromium (Cr + 3), which is less toxic and
more susceptible to chemical precipitation. Redox has also been used to
treat mercury-, silver-, and lead-contaminated wastes. Common
reducing agents include alkali metals (sodium, potassium) sulfur dioxide,
sulfite salts, ferrous sulfate, iron, aluminum, zinc, and sodium borohydrides.
Chemical oxidation is used primarily for treatment of cyanide and dilute
waste streams containing oxidizable organics. Among the organics for
which oxidative treatment has been reported are aldehyde, mercaptans,
phenols, benzidme, unsaturated acids, and certain pesticides. Common
commercially available oxidants include potassium permanganate,
hydrogen peroxide, hypochlorite, and chlorine gas.
The chemical redox treatment process consists of initial pH adjustment,
addition of redox reagents, mixing, and treatment to remove or precipitate
the reduced or oxidized products Chemical redox has limited application to
sludges because of difficulties m achieving intimate contact between the
reagent and the hazardous constituent. Sludges must be slurried prior to
treatment to achieve a suspended solids content of 3 percent or less.
Chemical redox is not well suited for high-strength, complex waste
streams. The most powerful oxidants and reductants are relatively
nonselective, and any oxidizable/reducible constituents in the waste may be
treated. For highly concentrated waste streams this will result in the need to
add large concentrations of reagent to treat target compounds.
The chemical redox process generates a solids/liquids effluent that
requires further treatment. If the reduced hazardous components are still in
a soluble form under system conditions, chemical precipitation methods
must be employed to convert these components to an insoluble form.
Following reduction and/or precipitation, the solids must be separated from
the liquid by filtration, settling, or evaporation. Chemical oxidation reactions
with organics are frequently incomplete, requiring biological or carbon
adsorption post treatment When using the chemical reduction-oxidation
technique for treating chlorinated organics, a possibility of producing HCI
exists Leach tests should be conducted on the residual solids to determine
the need for stabilization before imal disposal. The liquid effluent should be
analyzed before discharge to ensure regulatory compliance.
Wastes that can be treated via redox include: (a) benzene, phenols, most
organics, cyanide, arsenic, iron, and manganese (oxidation treatment) and
(b) chromium (VI), mercury, lead, silver, chlorinated organics like PCBs, and
unsaturated hydrocarbons (reduction treatment).
Status: This technology is widely available for RCRA wastes and is
potentially applicable to a variety of CERCLA wastes.
Figure B.9-1 illustrates the chemical reduction-oxidation process, and
Table B.9-1 is a technology restriction table.
95
-------
EPA Contact:
Charles J. Rogers, (513) 569-7757, FTS 684-7757
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendor:
No specific names of vendors are listed
here since the technology is widely available
Figure 8.9-7 Chemical reduction/oxidation.
Reduced Waste
Mixing Tank
Source EPA
96
-------
Table B.9-1 Technology Summary.
Waste Type: Sludges
Technology: Chemical Reduction/Oxidation
Waste
Characteristics
Impacting Process
Feasibility
Organic content
Variation in waste
composition
Chromium (+3),
mercury, lead,
silver
High viscosity
Reason for Potential Impact
Oxidizable organics in the sludge
will create competing redox
reactions, therefore requiring larger
amounts of oxidation/reduction
reagent.
Chemical redox is indiscriminate;
unwanted side reactions could
occur.
Oxidation of organic sludges will
oxidize these metals to their more
toxic and mobile forms.
Subsequent need for addition of
liquid to aid mixing.
Data
Collection
Requirements
Analysis for
priority
pollutants,
chemical
oxygen
demand
(COD)
analysis
Statistical
sampling.
priority
pollutant
analysis
Analysis for
total
chromium.
mercury, and
silver
Bench-scale
testing
Ref.
10
2,3
3
4
Low pH of sludge
Oil and grease
content
Suspended solids
content
A low pH (<2) may interfere with pH testing
redox reagents.
Oil and grease content of greater Analysis for
than 1% by weight interferes with oil and
reactant/waste contact. grease
A suspended solids content of Total
greater than 3% by weight can suspended
interfere with reductant/waste solids
contact inhibiting reduction.
Sludges therefore will need to be
slurried prior to treatment.'
11
' See Table 4.
97
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B.10 In Situ Vitrification
Technology Description
In situ vitrification (ISV) is the process of melting wastes and soils or
sludges in place to bind the waste in a glassy, solid matrix resistant to
leaching and more durable than granite or marble. ISV technology is based
on the concept of joule-heating to electrically melt soil or sludge. Melt
temperatures are in the range of 1600 to 2000 °C and act to destroy organic
pollutants by pyrolysis. Although the process was initially developed to
provide enhanced isolation to previously disposed radioactive wastes, the
process may also destroy or immobilize many inorganic and organic
hazardous chemical wastes. There are several general areas where the ISV
process might be applied to hazardous waste: contaminated soil sites,
burial grounds, tanks that contain a hazardous heel in the form of either a
sludge or a salt cake, and process sludges.
In the ISV process, four electrodes are inserted into the soil to the
desired treatment depth. A conductive mixture of flaked graphite and glass
frit is usually placed among the electrodes to act as the starter path for the
electrical circuit. Heat from the high current of electricity passing through
the electrodes and graphite creates a melt. The graphite starter path is
eventually consumed by oxidation, and the current is transferred to the
molten soil, which is now electrically conductive. As the melt grows
downward and outward, it incorporates nonvolatile elements and destroys
organic components by pyrolysis. The pyrolyzed byproducts migrate to the
surface of the vitrified zone, where they combust in the presence of
oxygen. Inorganic materials are dissolved into or are encapsulated in the
vitrified mass. Convective currents within the melt uniformly mix materials
that are present in the soil. When the electric current ceases, the molten
volume cools and solidifies. A hood placed over the processing area
provides confinement for the combustion gases, drawing the gases into an
off-gas treatment system.
Specific site characteristics must be considered in determining the
applicability of ISV. In the event that feasibility tests indicate problems in
soil conductance or vitrification, sand, soda ash, or glass frit can be mixed
with the soil to improve the process. A combination of high soil permeability
and the presence of ground water can create economic limitations to the
process. The process will work with fully saturated soils; however, the water
in the soil must be evaporated before the soil will begin to melt. If the soil
moisture is being recharged by an aquifer, there is an additional economic
impact. Soils with permeabilities higher than 10"4 cm/sec are difficult to
vitrify in the presence of flowing ground water and therefore require
temporary ground-water diversion, if practical, during processing. If buried
metals, such as drums, occupy over 90 percent of the linoar distance
between electrodes, a conduction path that leads to electrical shorting
between electrodes may result.
The environmental impact of the off-gas must also be addressed when
considering ISV. A hood must be placed over the processing area to collect
volatiles driven off during startup, combustion gases, and steam and
convey them into the off-gas treatment system. The depth of inorganics,
such as cadmium or lead, has a direct effect on the retention of the
inorganic in the melt. The presence of combustibles can provide a path to
the surface by entraining heavy metal oxides in the combustion product
gases. The closer they are to the surface, the more likely it is that the
entrained materials will not be removed and recaptured by the melt or
recaptured in the off-gas treatment system. Individual applications must
98
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be reviewed in detail prior to making final applicability decisions. Small-
scale feasibility tests and detailed site mapping are of vital importance.
By-products of the process include an aqueous scrub solution. When
scrub solution contains low levels of contaminants, residual treatment may
be required. See Table 6 for more detail on residuals treatment.
Figure B.10-1 illustrates the in situ vitrification process, and Table
B.10-1 is a technology restriction table.
EPA Contact:
Jonathan Herrmann, (513) 569-7839 FTS 684-7839
U.S Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendor:
James Hansen, (206) 822-4000
GeoSafe Corporation
303 Parkplace Suite 126
Kirkland, WA 98033
99
-------
Figure B.I0-1. In situ vitrification.
to Treatment
Off Gas-
Graphite
and Frit
Starter
Hood
Electrode
a i
Melting
Zone
3 !
Backfill
Vitrified Soil/Waste
Source: Battelle Pacific Northeast Laboratories
-------
Table B.10-1 Technology Summary.
Waste Type:
Technology:
Soils and Sludges
In Situ Vitrification
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data Collection
Requirements
Ref.
Severely limits economic
practicality because much
energy will be expended in
driving off water.
Buried metals can result in a
conductive path that would lead
to electrical shorting between
electrodes.
May start underground fire.
Time-ordered limits to the
capacity of the off-gas system
to contain combustion gas. Not
cumulative capacity.
Time-ordered limits to the
capacity of the off-gas system
to contain combustion gas. Not
cumulative capacity.
Time-ordered limits to the
capacity of the off-gas system
to contain combustion gas. Not
cumulative capacity.
Retention of volatile metals in
melt is reduced as surface is
approached. Clean soil may be
placed on top to increase depth
to which off-gas treatment mey
be relied on.
Combustible liquids 9600 Ib/yd of depth or 7% by
weight.
Presence of
ground water and
soil permeability
less than 1 x 10-5
cm/sec
Buried metals
(drums) occupying
over 90% of linear
distance between
electrodes
Loosely packed
rubbish, buried
coal
Combustible
liquids' (9600 Iblyd
of depth or7wt"/»)
Combustible
solids* (6400 Ib/yd
of depth or 4.7 wt
%, including 30%
soil with the
solids)
Combustible
packages" (1.2 yd3
or 32 ft3)
Volatile metal
content and depth
Percolation
test/water table
mapping
Site mapping
Site mapping
Site mapping,
analysis for
priority
pollutants,
feasibility testing
Site mapping,
analysis for
priority
pollutants,
feasibility testing
Site mapping,
analysis for
priority
pollutants,
feasibility testing
Site mapping,
analysis for Cd,
Pb, Hg, As
12
12
12
12
12
12
Void volumes
5-6 yd3 or 152 ft3.
Concentration limits are generic in nature; individual applications need to be
reviewed in detail.
Vendor information sheet.
101
-------
References
(1) In situ flushing and soils washing technologies for Superfund sites.
1985. Presented at RCRA/Superfund Engineering Technology Transfer
Symposium by Risk Reduction Engineering Laboratory, U.S.
Environmental Protection Agency, Cincinnati, Ohio.
(2) USEPA. 1986. U.S. Environmental Protection Agency, Office of Solid
Waste and Emergency Response. Mobile treatment technologies for
Superfund wastes. #540/2-86/003(f). Washington, D.C.: U.S.
Environmental Protection Agency.
(3) Akers, C.K., Pilie, R.J., and Michalouic, J.G. 1981. Guidelines for the
use of chemicals in removing hazardous substance discharges.
EPA - 600/52-81-25.
(4) Ellis, W.D., and Payne, J.R. The development of chemical
countermeasures for hazardous waste contaminated soil. Edison, N.J.:
Oil and Hazardous Materials Spills Branch, U.S. Environmental
Protection Agency.
(5) Cullinane, M.J., Jr., Bricka, R.M., and Francingues, N.R., Jr. 1987. An
assessment of materials that interfere with stabilization/solidification
processes. In land Disposal, Remedial Action, Incineration, and
Treatment of Hazardous Waste, Proceedings of the Thirteenth Annual
Research Symposium. Cincinnati, Ohio U.S. Environmental Protection
Agency, Risk Reduction Engineering Laboratory.
(6) Noland, N.W., McDevitt, N., and Koltuniak, D. 1985. Low temperature
thermal stripping of volatile organic compounds from soils. Edgewood,
Maryland: U.S. Army Toxic and Hazardous Materials Agency,
Aberdeen Proving Ground.
(7) Malot, J. 1985. Vacuum extraction of VOC contamination in soils.
Dorado, Puerto Rico: Terra Vac, Inc.
(8) USEPA. 1985. U.S. Environmental Protection Agency, Office of
Research and Development. 1985 handbook - remedial action at
waste disposal sites. Risk Reduction Engineering Laboratory, Office of
Research and Development. #625-6-85-006. Cincinnati, Ohio: U.S.
Environmental Protection Agency.
(9) Cullinane, M., Jr., Jones, L.W., and Malone, P.G. 1986. Handbook for
stabilization/solidification of hazardous waste. Cincinnati, Ohio: U.S.
Environmental Protection Agency, Risk Reduction Engineering
Laboratory.
(10) USEPA. 1979. U.S. Environmental Protection Agency. Survey of
solidification/stabilization technology for hazardous industrial waste by
environmental laboratory - U.S. Army Engineer Waterways
Experiment Station, Vicksburg, Miss. #600/2-79-056.
(11)Versar Inc. 1985. Assessment of treatment technologies for hazardous
waste and their restrictive waste characteristics. Vol. 1A-D.
Washington, D.C.: U.S. Environmental Protection Agency, Office of
Solid Waste.
(12)Fitzpatrick, V.F., Timmerman, C.L., and Buelt, J.L. 1986. In-situ
vitrification - a candidate process for in-situ destruction of hazardous
waste. Presented at the Seventh Superfund Conference, Washington,
D.C., December 1-3, 1986. Richland, Washington: Pacific Northwest
Laboratory.
102
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Appendix C
Biological Treatment Technologies
Introduction
Several well-developed biological technologies exist for the treatment
of aqueous waste streams contaminated at various levels with
nonhalogenated organics and some halogenated organics. The subject of
this appendix, however, is the biodegradation of organic contaminants in
sludges and soils. Contaminated sludges and soils can be biologically
treated in situ or excavated and treated by solid-phase and slurry-phase
bioremediation processes. Solid-phase and slurry-phase processes are
being developed, and in some cases have been used, to treat a wide range
of contaminants such as pesticides, diesel, gasoline, fuel oil, creosote,
pentachlorophenol, and halogenated volatile organics. Enhanced in situ
biodegradation is being used for sites having soil and ground water
contaminated with readily biodegradable organics such as gasoline and
diesel This technology is being developed for contaminants that are more
difficult to degrade.
This appendix contains information on biological treatment technologies.
For each technology, a technology description is provided, followed by an
illustration of the process and a technology restriction table. Each
technology restriction table includes a listing of the characteristics
impacting the feasibility of the process, reasons for restriction, data
collection requirements, and references. The numbers in the "Reference"
column are correlated with the list of references included at the end of this
appendix.
103
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C.1 Biodegradation
Technology description
Biodegradation is the bio-oxidation of organic matter by micro-
organisms. Composting, in situ biodegradation, solid-phase and slurry-
phase treatment are four biodegradation techniques applicable to soils and
sludges. In situ biodegradation is discussed separately.
C.1.1 Composting
Composting involves the storage of highly biodegradable and structurally
firm material (e.g., chopped haw, wood chips, etc.) with a small percentage
(<10%) biodegradable waste. Composting is enhanced by waste size
uniformity. Adequate aeration, optimum temperature, moisture and nutrient
contents, and the presence of an appropriate microbial population are
necessary to enhance decomposition of organic compounds.
There are three basic types of composting: open windrow systems,
static windrow systems, and in-vessel (reactor) systems. The open
windrow system consists of stacking the compost into elongated piles.
Aeration is accomplished by tearing down and rebuilding the piles. The
static windrow system also involves long piles of compost. However, the
piles are aerated by a forced air system; i.e., the piles are built on top of a
grid of perforated pipes. Finally, the in-vessel system involves placing the
compost into an enclosed reactor. Aeration is accomplished by tumbling,
stirring, and forced aeration.
In general, compared to in situ biodegradation, composting is relatively
insensitive to toxicants. The optimum temperature range for composting is
between 10 and 45°C or between 50 and 70°C.
When treating CERCLA wastes, it is necessary to collect leachate and
runoff water from the composting beds. See Table 6 for information on
residuals management.
Composting has not been widely used but is potentially applicable to
both sludges and soils.
C.1.2 Slurry-Phase Treatment
A second biodegradation technology involves the treatment of
contaminated soil or sludge in a large mobile bioreactor. This system
maintains intimate mixing and contact of microorganisms with the
hazardous compounds and creates the appropriate environmental
conditions for optimizing microbial biodegradation of target contaminants.
The first step in the treatment process is to create the aqueous slurry.
During this step stones and rubble are physically separated from the waste,
and the waste is mixed with water, if necessary, to obtain the appropriate
slurry density. The water may be contaminated ground water, surface
water, or another source of water. A typical soil slurry contains about 50
percent solids by weight; a slurried sludge may contain fewer solids. The
actual percent solids is determined in the laboratory based on the
concentration of contaminants, the rate of biodegradation, and the physical
nature of the waste. The slurry is mechanically agitated in a reactor vessel
to keep the solids suspended and maintain the appropriate environmental
conditions. Inorganic and organic nutrients, oxygen, and acid or alkali for
pH control may be added to maintain optimum conditions. Microorganisms
may be added initially to seed the bioreactor or added continuously to
maintain the correct concentration of biomass. The residence time in the
bioreactor varies with the soil or sludge matrix, physical/chemical nature of
104
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the contaminant, including concentration, and the biodegradability of the
contaminants. Once biodegradation of the contaminants is completed, the
treated slurry is dewatered. The residual water may require further
treatment prior to disposal.
Depending on the nature and concentration of the contaminants, and the
location of the site, any emissions may be released to the atmosphere, or
treated to prevent emission. Fugitive emissions of volatile organic
compounds, for instance, can be controlled by modifying the slurry-phase
bioreactor so that it is completely enclosed. See Table 6 for information on
residuals management.
Aside from the biodegradability of a particular compound, other limiting
factors include the presence of inhibiting compounds and operating
temperature. Heavy metals and chlorides may inhibit microbial metabolism
because of their toxicity. The operating temperature range is approximately
15-70°C. Dissolved oxygen is also critical and must be monitored along
with pH, nutrients, and waste solubility.
One advantage of treatment in a contained process is that a remediation
system can be designed to pretreat waste contaminated with heavy metals
as well as biodegradable semi-volatile and volatile compounds. Soil
washing and extraction of metals using weak acids and chelating agents
can be combined with biological treatment by coupling two separate
slurry-phase reactors in series.
Several firms market slurry-phase biological treatment systems. Ecova
Corporation markets slurry-phase treatment for highly-contaminated soils
(e.g., up to 14,000 ppm pesticides). Ecova can combine their biological
system with several other processes to handle vapors and heavy metals.
Ecova's system removes debris greater than 0.25 inches in diameter prior
to transferring to the bioreactor.
Detox Industries uses a slurry-phase biological treatment system to
biodegrade chlorinated hydrocarbons with naturally occurring
microorganisms. Detox claims that the process is particularly suited to
degradation of RGBs in soil and in sludges.
MoTec calls its slurry-phase system liquid-solid contact digestion.
They specialize in treating soil and sludge contaminated with creosote and
pentachlorophenol but are also studying the application of their system to
other types of biodegradable waste. This system requires co-metabolites
which provide carbon and hydrogen that can be easily digested by the
microorganisms. Once the co-metabolites such as polynuclear aromatics,
chlorinated hydrocarbons, or chlorinated aromatics are consumed, the
bacteria begin to metabolize target molecules in the waste that resemble
the co-metabolites. After completion of treatment, the solids are allowed to
settle, and the water is decanted. The sludge is then air-dried, and the
water is treated.
C.7.3 Solid-Phase Treatment
Solid-phase soil bioremediation is a process that treats soils in an
above grade system using conventional soil management practices to
enhance the microbial degradation of contaminants. The system can be
designed to contain and treat soil leachate and volatile organic compounds.
A system used by Ecova consists of a treatment bed which is lined with
an 80-millimeter high-density liner with heat-welded seams. Clean sand
is placed on top of the line to provide protection for the liner and proper
drainage for contaminated water as it leaches from contaminated soils
placed on the treatment bed. Lateral perforated drainage pipe is placed on
105
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top of the synthetic liner in the sand bed to collect soil leachate. If volatile
contaminants must be contained, the lined soil treatment bed is completely
covered by a modified plastic film greenhouse. An overhead spray irrigation
system contained within the greenhouse provides for moisture control and a
means of distributing nutrients and microbial inocula to the soil treatment
bed.
Volatile organic compounds which may be released from the soil during
processing are swept through the structure to an air management system.
Biodegradable volatile organic compounds can be treated in a vapor phase
bioreactor. Non-biodegradable volatile organic compounds can be
removed from the effluent gas stream by adsorption on activated carbon or
incineration.
Contaminated leachate which drains from the soil is transported by the
drain pipes and collected in a gravity-flow lined sump and then pumped to
an on-site bioreactor for treatment. Treated leachate can then be used as
a source of microbial inocula and reapplied to the soil treatment bed
through an overhead irrigation system, after adjusting for nutrients and
other environmental parameters.
Status: The MoTec technology has been used to treat pentachlorophenol
and creosote wastes, oil field and refinery sludges, and pesticide
wastewaters. The Detox process has been used to treat wastes containing
PCBs and pentachlorophenol. Ecova has applied slurry-phase bio-
remediation at the full scale to soil containing pesticides and diesel fuel,
and at the pilot scale to soil contaminated with polyaromatic hydrocarbons
(PAHs). Ecova has used solid-phase biodegradation at full scale to treat
soil containing gasoline, pesticides, and a mixture of motor oil and diesel,
and at the pilot scale to soils containing PAHs and pentachlorophenol.
Figure C.1-1 illustrates the slurry-phase biodegradation process,
Figure C.1-2 illustrates the solid-phase biodegradation system, and
Table C.1-1 is a technology restriction table.
EPA Contact:
Ronald Lewis, (513) 569-7856, FTS 684-7856
Eugene Harris, (513) 569-7862, FTS 684-7862
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
Vendors:
Tom Dardas, (713) 240-0892
Detox Industries, Inc.
12919 Dairy Ashford
Sugarland, TX
John Bogart, (615) 754-9626
MoTec, Inc.
P.O. Box 338
Mt. Juliet, TN 37122-0338
Al Bourquin, (206) 883-1900
Derek Ross (206) 883-1900
Ecova Corporation
3820 159th Avenue NE
Redmond, WA 98052
106
-------
Figure C.1-1. Slurry-phase biodegradation.
To Atmosphere
Biomass
Nutrients
Makeup Water
To Atmosphere
To Atmosphere
Source: MoTec, Inc.
-------
Figure C.1-2. Solid phase biodegradation.
o
03
Contaminated Soil
Excavation
Perforated
Dram Pipe
Soil
Screening
Solid-Phase
Treatment
Soil Layer
Compacted Clay
Oversized Material
to Special Handling
Sprinkler
System
Source: Ecova Corp.
-------
Table C.1-1 Technology Summary.
Waste Type: Soils and Sludges
Technology: Biodegradation
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data Collection
Requirements
Ref.
Variable waste
composition
Water solubility
Biodegradability
Temperature
outside iS-70'C
range
Inconsistent biodegradation caused
by variation in biological activity.
Contaminants with low solubility are
harder to biodegrade.
Low biodegradability inhibits
process.
Larger, more diverse microbial
population present in this range.
Nutrient deficiency Lack of adequate nutrients for
biological activity (although nutrient
supplements may be added).
Oxygen deficiency Lack of oxygen is rate limiting.
Moisture content
pH outside
4.5-8.5 range
Microbial
population
Water and air
emissions and
discharges
(composting only)
A moisture content of greater than
79% affects bacterial activity and
availability of oxygen. A moisture
content below 40% severely inhibits
bacterial activity.
Inhibition of biological activity
If indigenous microorganisms not
present, cultured strains can be
added.
Potential environmental and/or
health impacts (control achieved
through air scrubbing, carbon
filtration, forced aeration, cement
liner).
Waste
composition
Solubility
Chemical 1
constituents,
bench-scale
testing
Temperature 1,2
monitoring
CINIP ratio
Oxygen 1
monitoring
Ratio of air to 1,2,3
water in
interstices,
porosity of
composting
mass
Sludge pH
testing
Culture test 3
Concentrations 1
of
contaminants
109
-------
Table C.1-1 Technology Summary (continued).
Waste Type: Soils ami Sludges
Technology: Btodegradatfon
Characteristics
Impacting Process Date Collection
Feasibility Reason for Potential Impact Requirements Ref.
Compaction of Particles tend to coalesce and Determine 3
compost form an amorphous mass that is not integrity.
(composting only) easily maintained in an aerobic physical nature
environment (wood chips or of material
shredded tires may be added as
bulking agents).
Nonuniform Waste mixtures must be of uniform Particle size 2
particle particle size. distribution
(composting only)
Presence of Can be highly toxic to Analysis for 4,5
elevated levels of: microorganisms. priority
• Heavy metals pollutant
• Highly
chlorinated
organics
• Some
pesticides,
herbicides
• Inorganic salts
110
-------
C.2 In Situ Biodegradation
Technology Description
In situ biodegradation uses indigenous or introduced aerobic or
anaerobic bacteria to biodegrade organic compounds in soils. The
technology involves enhancing the natural biodegradation process by
injecting nutrients (i.e., phosphorus, nitrogen, etc.), oxygen, and even
cultured bacterial strains. It is also possible to adjust some environmental
parameters such as soil pH and temperature.
In situ biodegradation is often used in conjunction with a ground-water
pumping and reinjection system to circulate nutrients and oxygen through a
contaminated aquifer and associated soils. It can provide substantial
reduction in organic contaminant levels in soils without the cost of soil
excavation.
Under favorable conditions indigenous and/or introduced soil
microorganisms are known to degrade many organic compounds.
Microorganisms are capable of completely degrading organic compounds
into water and carbon dioxide in the presence of sufficient oxygen and
nutrients such as nitrogen and phosphorous, a near neutral pH, and warmer
soil temperatures. Anaerobic degradation of organics is possible although
the rates of degradation are generally too slow to constitute an active
remediation.
Enhanced biodegradation (bioreclamation) is one of the in situ methods
that is engineered to create favorable aerobic conditions in unfavorable
conditions such as nonhomogeneous soils, delicate geochemical balances,
and uncertain organic substrates. A major rate limiting factor in in situ
biodegration is the presence of dissolved oxygen. Hydrogen peroxide is
currently the preferred oxygen source; at 40 mg/l of ground water, it
releases enough oxygen to maintain continuous biodegradation. The
presence of iron in the subsurface causes hydrogen peroxide depletion at a
faster rate. A prerequisite for the application of hydrogen peroxide as an
oxygen source is soil pretreatment, which is necessary to prolong the
stability of peroxide in situ. Several phosphate compounds are currently
being tested as complexing agents for iron to increase the stability of
peroxide. Anaerobic pathways are also available but are generally
considered too slow to constitute active cleanup.
It is recommended that a control area be established on the upgradient
end of the site. The purpose of this area is to compare natural levels of
degradation to the enhanced biodegradation reaction provided by nutrient
and peroxide additions. An aeration and settling unit may be required to
reduce iron fouling if the iron content of the shallow ground water is greater
than 10 mg/l.
This technology is not suitable for soil contaminated with metals present
in inhibitory concentrations but is well suited for soil contaminated by
petroleum by-products.
Status: Ecova has applied this technology to solvents and chlorinated
aromatic compounds. The technology has been used most frequently to
treat soil contaminated with gasoline and diesel.
Figure C.2-1 is an illustration of in situ biodegradation. and Table C.2-
1 is a technology restriction table.
111
-------
EPA Contact:
John Wilson, (405) 332-8800, FTS 743-2259
U.S. Environmental Protection Agency
Robert S. Kerr Environmental Research Laboratory
Ada, OK 74820
Vendors:
Al Bourquin, (206) 883-1900
Derek Ross, (206) 883-1900
Ecova Corporation
3820 159th Avenue NE
Redmond, WA 98052
John Kopper, (201) 225-2000
IT Corporation
165 Fieldcrest Avenue
Edison, NJ 08818
Paul B. Trost, (303) 279-4255
MTA Remedial Resources, Incorporated
1511 Washington Avenue
Golden CO 80401
112
-------
Figure C.2-1. \ns\tubioremediation.
Chemical/Biological
Additive Control
and
Feed System
Injection
Well
Biological
Inoculum
Fermenter
•:• Bedrock
Source: Ecova Corp
-------
Table C.2-1 Technology Summary.
Waste Type: Soils and Sludges
Technology: In Situ Biodegradation
Characteristics
Impacting Process
Feasibility
Variable waste
composition
Water solubility
Biodegradability
Temperature
outside 25-70°C
Reason for Potential Impact
Inconsistent biodegradation caused
by variation in biological activity.
Contaminants with low solubility are
harder to biodegrade.
Low biodegradability inhibits
process.
Larger, more diverse microbial
population present in this range.
Data
Collection
Requirements
Waste
composition
Solubility
Chemical
constituents,
presence of
metals/salts,
bench-scale
testing
Temperature
monitoring
Ref.
1
1
1
1,2
range
Nutrient deficiency Lack of adequate nutrients for
biological activity (although nutrient
supplements may be added).
Oxygen deficiency Oxygen depletion slows down the
process.
Moisture content
pH outside
4.5-7.5 range
Microbial
population
A moisture content of greater than
79% affects bacterial activity and
availability of oxygen. A moisture
content below 4O% severely inhibits
bacterial activity.
Inhibition of biological activity.
If indigenous microorganisms not
present, cultured strains can be
added.
Presence of Can be highly toxic to
elevated levels of: microorganisms.
• Heavy metals
• Highly
chlorinated
organics
• Some
pesticides,
herbicides
• Inorganic salts
C/N/S ratio
Oxygen
monitoring
Ratio of air to
water in
interstices,
porosity of
composting
mass
Sludge pH
testing
Culture test
Analysis for
contaminams
1,2,3
4,5
114
-------
Table C2-J Technology Summary (continued).
Waste Type: Soils and Sludges
Technology: In Situ Biodegradation
Characteristics
Impacting Process
Feasibility
Reason for Potential Impact
Data Collection
Requirements
Ref.
Unfavorable soil
characteristics
• Low permeability
• Variable soil
conditions
• Low soil pH
Hinders movement of water and
nutrients through contaminated
area.
Inconsistent biodegradation due
to variation in biological activity.
Inhibition of biological activity.
• Low soil organic Lack of organic substrate for
content biological growth
• Low moisture Subsurface biological growth
content (< 10%) requires adequate moisture.
Unfavorable site
hydrology
Unfavorable
groundwater
quality parameters
• Low dissolved
oxygen
Groundwater flow patterns must
permit pumping for extraction
and rejection.
Oxygen necessary for biological
growth.
• Low pH, alkalinity Inhibition of biological activity.
Percolation
testing
Soil mapping
Soil pH testing
Soil humus
content
Soil moisture
content
Site
hydrogeology
must be well
defined.
Dissolved
oxygen in
ground water,
determine
amount of hy-
drogen per-
oxide needed to
satisfy oxygen
demand
pH and alkalinity
of ground water
4,5
4,5
4,5
4,5
115
-------
References
(1) USEPA. 1985. U.S. Environmental Protection Agency, Office of
Research and Development. 1985 handbook - remedial action at
waste disposal sites. Hazardous Waste Engineering Research
Laboratory, Office of Research and Development. #625-6-85-006.
Cincinnati, Ohio: U.S. Environmental Protection Agency.
(2) Versar Inc. 1985. Assessment of treatment technologies for hazardous
waste and their restrictive waste characteristics. Vol. 1A-D.
Washington, D.C.: U.S. Environmental Protection Agency.
(3) COM, Inc. 1985. Alternative treatment technologies for Superfund
wastes. Prepared for U.S. Environmental Protection Agency, Office of
Solid Waste. U.S. Environmental Protection Agency, Contract No. 68-
01-7953. Washington, D.C.: U.S. Environmental Protection Agency.
(4) USEPA. 1986. U.S. Environmental Protection Agency, Office of Solid
Waste and Emergency Response. Mobile treatment technologies for
Superfund wastes. #540/2-86/003(f). Washington, D.C.: U.S.
Environmental Protection Agency.
(5) USEPA. 1986. U.S. Environmental Protection Agency, Office of Solid
Waste and Emergency Response. Superfund treatment technologies: a
vendor inventory. #540/2-86/004. Washington, D.C.: U.S.
Environmental Protection Agency.
116
-------
Appendix D
Selected Reference Tables
117
-------
Table D-1 Examples of Constituents Within Waste Groups.
HALOGENATED VOLATILES
Bromodichloromethane
Bromoform
Bromomethane
Carbon tetrachlonde
Chlorodibromomethane
Chlorobenzene
Chloroethane
Chloroform
Chlommethane
Chloropropane
Dibromomethane
Cis, 1,3-dichloropropene
1,1-Dichloroethane
1,2-Dichloroethane
1,1 -Dichloroethene
1,2-Dichloroethene
1,2 -D/chloropropane
Fluorotrichloromethane
Methylene chloride
1,1,2,2-tetrachloroethane
Tetrachloroethene
1,1,1-Trichloroethane
1,1,2-Trichloroethane
1,2-Trans-dichloroethene
Trans -1,3-dichloropropene
i,i,2-trichloro-i,2,2-tnfluoroethane
Tnch/oroethene
Vinyl chloride
Total chlorinated hydrocarbons
Hexachloroethane
Dichloromethane
HALOGENATED SEMIVOLATILES
2-ch/orophenol
2,4-dichlorophenol
Hexachlorocyclopentadiene
p-chloro -m -cresol
Pentachlorophenol
Tetrachlorophenol
2,4,5 -trichlorophenol
2,4,6-trichlorophenol
Bis-(2 -chloroethoxy)methane
Bis(2-chloroethyl)ether
Bis(2-chloroisopropyl)ether
4-bromophenyl phenyl ether
4-chloroanihne
2-chloronapthalene
4-chlorophenyl phenylether
1,2-dichlorobenzene
1,3-dichlorobenzene
1,4-dichlorobenzene
3,3 -dichlorobenzidine
Hexachlorobenzene
Hexachlorobutadiene
7,2,4-fricWorotoenzene
HALOGENATED SEMIVOLATILES (cont)
Bis(2-chloroethoxy)phthalate
Bis(2-chloroethoxy)ether
1,2-bis(2-chloroethoxy)ethane
NONHALOGENATED VOLATILES
Acetone
Acrolein
Acrylonitrile
Benzene
2-butanone
Carbon disulfide
Cyclohexanone
Ethyl acetate
Ethyl ether
Ethyl benzene
2-hexanone
Isobutanol
Methanol
Methyl isobutyl ketone
4 -methyl-2 -pentanone
n-butyl alcohol
Styrene
Toluene
Trimethyl benzene
Vinyl acetate
Xylenes
NONHALOGENATED SEMIVOLATILES
Benzole acid
Cresols
2,4-dimethylphenol
2,4-dinitrophenol
2-methylphenol
4-methylphenol
2-n/trophenol
4-nitrophenol
Phenol
Acenaphthene
Acenapthylene
Anthracene
Benzidine
Benzo(a)anthracene
Benzo(b)ftuoranthene
Benzo(k)fluoranthene
Benzo(a)pyrene
Benzo(ghi)perylene
Benzyl alcohol
Bis(2-ethylhexyl)phthalate
Butyl benzyl phthalate
Chrysene
Dibenzo(a,h)anthracene
Dibenzofuran
Diethyl phthalate
Dimethyl phthalate
Di-n-butyl phthalate
118
-------
Table D-1 Examples of Constituents Within Waste Groups (continued).
4,6-dimtro-2-methylphenol
2,4-dinitrotoluene
2,6-dimtrotoluene
Di-n-octyl phthalate
1,2-diphenylhydrazine
Fluoranthene
Fluorene
lndeno( 1,2,3 -cd)pyrene
Isophorone
2-methylnapthalene
Napthalene
2-nitroanilme
3-nitroanilme
4-nitroanilme
Nitrobenzene
n-nitrosodimethylamme
n-nitrosodi-n-propylamme
n-nitrosodiphenyiamme
Phenanthrene
Pyrene
Pyrtdine
2-methynaphthalene
Bis phthalate
Phenyl napthalene
PESTICIDES
Aldnn
Bhc-alpha
Bhc-beta
Bhc-delta
Bine-gamma
Chlordane
4,4'-ODD
4,4'-DDE
4,4'-DDt
Dieldrin
Endosulfan I
Endosulfan II
Endosulfan su/fate
Endrin
Endrin aldehyde
Ethion
Ethyl parathion
Heptachlor
Heptachlor epoxide
Malathion
Methylparathion
Parathion
Toxaphene
VOLATILE METALS
Arsenic
Bismuth
VOLATILE METALS (cont)
Lead
Mercury
Tin
Selenium
OTHER CATEGORIES
Asbestos
INORGANIC CORROSIVES
Hydrochloric acid
Nitric acid
Hydrofluoric acid
Sulfunc acid
Sodium hydroxide
Calcium hydroxide
Calcium carbonate
Potassium carbonate
PCBs
PCB (Arochlor)-10T6
PCB (Arochlor)-1221
PCB (Arochlor)-l232
PCB (Arochlor)-l242
PCB (Arochlor)-1248
PCB (Arochlor)-1254
PCB (Arochlor)-1260
PCB NOS (not otherwise specified)
ORGANIC CORROSIVES
Acetic acid
Acetyl chloride
Aniline
Aromatic Sulfonic acids
Cresylic acid
Formic acid
NONMETALLIC TOXIC ELEMENTS
Fluorine
Bismuth
NONVOLATILE METALS
Aluminum
Antimony
Barium
Beryllium
Bismuth
Cadmium
Calcium
Chromium
Copper
Cobalt
Iron
Magnesium
119
-------
Table D-1 Examples of Constituents Within Waste Groups (continued).
NONVOLATILE METALS (cont) ORGANIC CYANIDES
Manganese Organonitriles
Nickel
Potassium INORGANIC CYANIDES
Selenium Cyanide
Sodium Metallic cyanides
Vanadium (e-9- ferricyanide,
sodium cyanide)
Radioactive isotopes of Chromates
iodine, barium, uranium
Radium REDUCERS
Gamma radioactivity Sulfides
Radon: alpha radioactivity Phosphides
Hydrazine
120
-------
Table D-2 Waste Technology Matrix Soils.
[ Contaminant
Organic
o
ed bed incinerati
_N
Table <•
Technology
ISSiSl'SwH
01
kiln incineration
d thermal treatm
sis-incineration
at ion
^ 0) >* O
« « 2 «
CC JE Q- >
CM CO IO 03
< <
c < <
WSft-iSSSS?
a)
cal extraction
chemical treatm
11
0 £
T- CM
m m
TO
C
'.C
w
CO
CO
m
\
*}
en
c
'o
c/)
3
C
4
m
c
ate dechlorinatio
1
O
IT)
m
E1 c
a o
•9- T?
•t: m
« 2
mperature therm
vacuum/steam
OJ 3
^ =
UD l~~
m CD
o
zation/solidificat
1
w
00
m
LI vitrification
0
m
radation
biodegradatlon
y a
0 «
in S
*- CM
O O
Halogenated volatiles
Halogenated semivolatiles
Nonhalogenated volatiles
Nonhalogenated semivolatiles
PCBs
Pesticides
Organic cyanides
Organic corrosives
Inorganic
Volatile metals
Nonvolatile metals
Asbestos
Radioactive materials
Inorganic corrosives
Inorganic cyanides
Reactive
Oxidizers
Reducers
* Do not use this matrix table
alone. Please refer to the cit
appendices for guidance.
O
•
•
Q
e
e
O
d
e
g
e
e
e
Q
Q
O
Q
e
9
9
9
9
o
9
9
O
O
O
O
O
o
o
o
9
9
9
9
9
9
9
9
X
9
9
X
X
O
o
o
o
o
X
o
0
0
o
o
X
o
o
o
o
Q
o
0
o
o
d
Q
X
e
•
o
Q
Q
0
0
O
O
D
O
o
o
o
o
9
Q
9
9
0
0
9
9
9
9
O
O
9
O
O
O
0
0
O
O
O
O
o
o
o
o
o
o
o
o
o
o
•
•
•
•
•
•
g
9
9
•
9
9
X
X
o
X
X
X
X
X
o
X
X
X
9
Q
•
•
ed
9
Q
e
o
9
O
X
X
9
O
9
9
o
O
o
O
o
o
o
o
9
9
f^ Demonstrated effectiveness^
Q Potential effectiveness
Q No effectiveness
X Potential adverse impacts to
. process or environment i
^^ , **$>
9
9
X
X
X
X
^2^
-------
Table D-3 Waste Technology Matrix: Sludges.
Organ
Hale
Nor
Nonhalc
Inorga
Reacth
* Do not
alone.
appem
uidized bed incineration
Contaminant ]K "-
c Table
Halogenated volatiles
genated semivolatiles
ihalogenated volatiles
genated semivolatiles
PCBs
Pesticides
Organic cyanide
Organic corrosives
nic
Volatile metals
Nonvolatile metals
Asbestos
Radioactive materials
Inorganic corrosives
Inorganic cyanides
/e
Oxidizers
Reducers
use this matrix table
Please refer to the cited
dices for guidance.
Rotary kiln incineration
Infrared thermal treatment
[Technology j
Wet air oxidation
Pyrolysis-incineration
Vitrification
Chemical extraction
In situ chemical treatment
Glycolate dechlorination
Stabilization/solidification """"
Chemical reduction oxidation
-1 In situ vitrification
Biodegradation
In situ biodegradation
•Acsicb 4- in cb ch T-T^-CXJ
< < < < < < m m m m CD cd d d
Q
d
Q
Q
Q
Q
9
Q
•
•
•
•
•
•
•
•
•
•
•
•
•
O
Q
Q
O
Q
Q
d
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e
Q
d
9
e
o
e
Q
o
Q
Q
Q
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9
o
Q
Q
Q
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e
•
Q
•
•
Q
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O
o
o
o
o
o
o
Q
d
o
0
o
o
9
Q
o
o
Q
e
o
Q
0
9
Q
Q
9
O
Q
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9
e
•
o
d
e
Q
Q
e
e
Q
Q
Q
Q
d
d
Q
d
o
X
Q
Q
e
d
Q
O
e
X
X
o
o
o
o
g
X
o
o
o
o
Q
X
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o
0
o
o
o
o
o
o
o
o
o
0
Q
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Q
Q
X
Q
•
e
e
9
o
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o
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o
e
Q
o
0
o
o
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o
•
•
•
•
•
•
o
e
o
o
o
•
e
d
o
•
o
Q
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X
o
X
X
X
X
X
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X
X
X
Q
9
®
Q
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e
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9
9
Q
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9
X
X
e
Q
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o
9
9
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e
(^ Demonstrated effectiveness i>
Q Potential effectiveness
Q No effectiveness
X Potential adverse impacts to
, process or environment >
\^ ^K:
X
X
X
X
<
'.;
1
122
-------
Table D-4 PretreatmentlMaterials Handling Table: Sludges.
Problem
Treatment/Solution
Material Dragline Crane-operated excavator bucket to dredge
transport and or scrape sludge from lagoons, ponds, or
excavation pits.
Backhoes, Useful for subsurface excavation or at the
excavators original ground level.
Mudcat Bulldozer or loader much like a crawler
capable of moving through sludge.
Positive Pump that can handle high-density sludges
displacement containing abrasives such as sand and
pump (e.g., gravel.
cement pump)
Moyno pump Progressing cavity pump that can pump
high-viscosity sludges.
Excessive Evaporator Excess water can be evaporated from
water content sludge. The Carver-Greenfield process is a
potentially applicable technology. The sludge
is mixed with oil to form a slurry, and the
moisture is evaporated through a multiple-
effect evaporator.
Filter press Sludge is pumped into cavities formed by a
series of plates covered by a filter cloth. The
liquid seeps through the filter cloth, and the
sludge solids remain.
Belt filter Sludge drops onto a perforated belt, where
gravity drainage takes place. The thickened
sludge is pressed between a series of rollers
to produce a dry cake.
Vacuum filter Sludge is fed onto a rotating perforated drum
with an internal vacuum, which extracts liquid
phase.
Centrifuge Sludge feeds through a central pipe that
(solid bowl) sprays it into a rotating bowl. Centrate
escapes out the large end of the bowl, and
the solids are removed from the tapered end
of the bowl by means of a screw conveyer.
Drying Rotary drying, flash drying, sand bed.
Gravity Slurry enters thickener and settles into
thickening circular tank. The sludge thickens and
compacts at the bottom of the tank, and the
sludge blanket remains to help further
concentration.
Chemical Compounds may be added to physically or
addition chemically bind water
123
-------
Table D-4 Pretreatment/Materials Handling Table: Sludges (continued).
Problem
Excessive
sludge
viscosity
Extreme pH
Treatment/Solution
Slurry
Neutralization
Addition of water or solvent.
Addition of dispersants
Lime, an alkaline material, is
widely used for
neutralizing acid wastes; sulfuric acid is used
to neutralize alkaline wastes.
Oversized
material.
removal
disaggregation,
sorting
See Table 5
(Soils)
Table D-5 Pretreatment/Materials Handling Table: Soils.
Problem
Treatment/Solution
Material
transport and
excavation
Oversized
material
removal,
disaggregation,
sorting
Dragline Crane-operated excavator bucket to dredge
or scrape soil to depths and farther
reaches..
Backhoes Useful for subsurface excavation or at the
original ground level.
Heavy Includes bulldozers, excavators, and dump
earthmoving trucks for excavation and transport.
equipment
Conveyers May be useful for large-volume transport or
feed to treatment unit.
Vibrating Vibrates for screening of fine particles from
screen dry materials. There is a large capacity per
area of screen, and high efficiency. Can be
clogged by very wet material.
Static screen A wedge bar screen consists of parallel bars
that are frame-mounted. A slurry flows down
through the feed inlet and flows tangentially
down the surface of the screen. The curved
surfaces of the screen and the velocity of the
slurry provide a centrifugal force that
separates small particles.
Grizzlies Parallel bars that are frame-mounted at an
angle to promote materials flow and
separation. Grizzlies are used to remove a
small amount of oversized material from
predominantly fine soil.
Hammer mill Used to reduce particle size of softer
materials.
124
-------
Table 0-5 Pretreatment/Materials Handling Table: Soils (continued).
Problem
Treatment/Solution
Oversized
material
removal,
disaggregation,
sorting (cont.)
Impact
crushers
Break up feed particles by impact with
rotating hammers or bars. Impact crushing
works best with material that has several
planes of weakness, such as impurities or
cracks.
Shredder Reduces size of waste material. Shredders
are available to handle most materials,
including tires, metal, scrap, wood, and
concrete.
Tumbling mill Reduces size of rock and other materials
using a rotating drum filled with balls, rod,
tubes, or pebbles.
Cyclone Separates different sized particles by
centrifugation and gravity.
Fugitive Dust Natural (e.g., water) or synthetic materials that
emissions suppressant strengthen bonds between soil particles.
Negative Vacuum systems that may be used to collect
pressure air vapors and/or dust particles and prevent
systems release into atmosphere.
Foams Applied to soil surface to control volatile
emissions and dust during excavation
Covered Temporary shelter with structurally or air
shelters supported cover to restrict emissions to
enclosed volume.
Dewatering Belt filter Useful for dewatering of very wet soils
press, (lagoon sediments, wetlands).
centrifuge
Rotating dryer Additional drying may permit higher feed
rates for thermal treatment systems.
125
-------
Table 0-6 Residuals Management
Technology
Residual Generating Residual Contaminants
Potential Management
Treated Fluidized bed
soil or ash incineration, infrared
thermal treatment,
rotary kiln incineration
Metals
Treated
soil
Low-temperature
thermal stripping
Afterburner Low-temperature
ash thermal stripping
Solids
(ash)
Glass
residue
Solids
Spent
activated
carbon
Fly ash
Leachate
Aqueous
effluent
Wet air oxidation
Vitrification
Chemical extraction
- basic extractive
sludge treatment
Low-temperature
thermal stripping, air
pollution control
device, wastewater
treatment
Electrostatic precip-
itator, baghouse,
cyclone
Biodegradation,
stabilization/
solidification
Chemical extraction,
soil washing
Wet air oxidation
Metals,
nonvolatile
organics
Volatile metals
Metal oxides,
insoluble salts
Nonvolatile
metals at the
operating
temperature
Metals, trace
organics
Volatile organics
Volatile metals
Trace metals
Trace organics
Trace organics
Carboxylic acids
and other
carbonyl group
compounds; low
molecular weight
organics, such
as acetaldehyde,
acetone,
methanol
Stabilization/solidification
Vitrification
Stabilization/solidification
Vitrification
Stabilization/solidification
Vitrification
Mechanical dewatering
Stabilization/solidification
Disposal
Stabilization/solidification
Vitrification
Incineration, thermal
regeneration, wet air
oxidation, steam strip-
ping with water treatment,
biodegradation
Stabilization/solidification,
recycle to primary
thermal unit, reuse of ash
Chemical precipitation
Stabilization/solidification
Biological treatment or
carbon adsorption,
photooxidation, chemical
oxidation
Biological treatment or
carbon adsorption
Biological treatment or
carbon adsorption,
photooxidation, chemical
oxidation
126
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Table D-6 Residuals Management (continued).
Technology
Residual Generating Residual
Contaminants
Potential Management
Water/
reagant mix
Water/
flushing
agent mix
Glycolate
dechlorination
Soil washing/
soil flushing
Organic
effluent
Scrubber
water
Off-gas
Solvent extraction
Incineration
(fluidized bed
incineration, rotary
kiln incineration,
vitrification unit,
infrared thermal
treatment), off-gas
collection and
treatment
In situ vitrification
Stabilization/
solidification
Wet air oxidation
Organics
Organics
Metals
Cyanides
Organics (non-
PCBs)
Organics mixed
with PCBs
Caustic, high
chloride content,
volatile metals,
organics, metal
particulates, and
inorganic
particulates
Trace levels of
combustion
products, volatile
metals, and/or
volatile organics
Ammonia
Volatile organics
Low molecular
weight
compounds,
such as
acetaldehyde,
acetone, acetic
acid, methanol
Distillation followed by
incineration
Distillation, carbon
adsorption, biological
treatment, chemical
oxidation, photochemical
oxidation
Chemical precipitation
Chemical oxidation, wet
air oxidation, electrolytic
oxidation, photochemical
oxidation
Recycle or reuse as fuel
Incineration
Neutralization, chemical
precipitation, reverse
osmosis, settling ponds,
evaporation ponds,
filtration, and gas phase
incineration of organics,
chemical oxidation,
photochemical oxidation
Gas scrubber, activated
carbon adsorption
Gas scrubber
Carbon adsorption
Gas scrubber, carbon
adsorption, fume
incineration, biological
treatment
•tr U.SGPO 1988-548-158/87017
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