UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. D.C. 20460
0-e'CE 0-
S-E -iNOEVEOGeS
OSWER Directive No. 9200.5-220
MEMORANDUM
SUBJECT: Guidance on Key Terms Used in Superfund
FROM: Timothy Fields, Jr., Acting Director
Office of Emergency and Remedial Response
TO: Directors, Waste Management Division, Regions I, iv, v,
VII, and VIII
Director, Emergency and Remedial Response Division,
Region II
Directors, Hazardous Waste Management Division,
Region III, VI, IX
Director, Hazardous Waste Division, Region X
Directors, Environmental Services Division, Regions I,
VI, and VII
PURPOSE
The purpose of this memorandum is to provide, as guidance,
suggested definitions for three^Jcey terms^ which are used in the
Super fund program and to transmit two drTft fact-sheets^ for,
review which address two of"these terms.The fact-sheet on the
third term, "Interim Actions," is being developed under a
separate effort and will be distributed separately. Comments are
requested by April 26, 1991. The final guidance is tentatively
scheduled for issuance this spring.
BACKGROUND
Several key terms have been identified by the Regions and
others as requiring additional guidance to ensure their
consistent application in the Superfund program. These terms are
as follows:
o Principal Threat Wastes
o Low Level Threat Wastes
o Immobilization
o Interim Actions
o Innovative Treatment Technologies
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The above terms were identified primarily because they play an
integral role in the Superfund remedy evaluation and selection
process and have been a source of some discussion as to their
appropriate use. For example, the terms principal threat wastes
and low level threat wastes are used to initially target wastes
for treatment or containment. The term immobilization (e.g.,
solidification/stabilization) was identified because of concerns
that have been raised as to the appropriate use of this treatment
technology for organic wastes. In the case of interim actions,
the meaning of the term has evolved over time.
Guidance on these terms is also needed to standardize their
use in reports on the Superfund program. Numerous studies have
been conducted to evaluate the Superfund program both within the
Agency and by outside parties. These studies have at times
presented different views of the Superfund program, sometimes due
to different definitions of key terms. For example, the
Superfund program has not used one consistent definition for the
term innovative treatment. It is hoped that by developing and
issuing Agency guidance on the meaning and use of these terms
that we will achieve a greater degree of uniformity in the
analysis of the Superfund program.
The terms principal threat and low level threat wastes are
of particular importance to the Superfund program. Some of the
issues raised by these terms are currently under consideration by
the National Superfund Risk Management Work Group. Therefore,
the draft fact-sheet is being provided to the Work Group for
review and comment prior to issuance to the Regions. We
anticipate that draft guidance definitions and a draft fact-sheet
will be available for Regional review this spring. The
information contained in the draft fact-sheet will be discussed
at the ROD Forums that are scheduled for April and May, 1991.
Definitionss This memorandum transmits, draft guidance on
defining three of the five key Superfund terms. The definitions
resulted from an effort to develop a detailed fact-sheet for each
term. The following definitions or policy statements provide an
overview of how these terms are to be applied:
1. Immobilisation is generally appropriate as a treatment
alternative only for material containing inorganics,
semi-volatile and/or non-volatile organics. Based on
present information, the Agency does not believe that
immobilization is an appropriate treatment alternative
for volatile organics. Selection of immobilization of
semi-volatile and non-volatile organics generally
requires the performance of a site-specific
treatability study or non-site-specific treatability
study data generated on waste which is very similar (in
terms of type of contaminant, concentration, and waste
matrix) to that to be treated and that demonstrates.
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through Total Waste Analysis (TWA), a significant
reduction (i.e., a 90-99 percent reduction) in the
concentration of chemical constituents of concern .
2. Innovative Treatment Technologies are those
technologies where limited available data on the
performance and/or cost inhibit their use for many
Superfund types of applications. Innovative treatment
technologies are considered based on the NCP
expectations for these technologies (40 CFR
300.430(a)(1)(iii)(E)). That is to say, innovative
technologies are generally considered when they offer
the "potential for comparable or superior treatment
performance or implementability, fewer or lesser
adverse impacts than other available approaches, or
lower costs for similar levels of performance than
demonstrated technologies." Because of the general lack
of available technologies we anticipate that at many
sites we will consider innovative technologies.
3. Interim Actions are temporary in nature and intended to
stabilize conditions and/or reduce threats from the
operable unit while a final solution to the operable
unit is studied and developed. Interim actions may be
taken under remedial or removal authority. For interim
action RODS, the intent is to revisit the action in a
subsequent final action ROD that will fully address the
statutory findings required by SARA.
The language provided for immobilization warrants further
explanation. The above "definition" is really a statement of
Agency policy as to when and how this treatment technology should
or should not be used. This policy was developed in response to
concerns regarding the types of treatment applications,
particularly for organic wastes, that provide for adequate
protection. This policy may change in the future as we gain
knowledge on the use of immobilization for organic wastes and
leachability testing.
1 The 90-99 percent reduction in contaminant concentration
is a general guidance and may be varied within a reasonable range
considering the effectiveness of the technology and the clean-up
goals for the site. Although this policy represents EPA's strong
belief that TWA should be used to demonstrate effectiveness of
immobilization, other leachability tests may also be appropriate
in addition to TWA to evaluate the protectiveness under a
specific management scenario.
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Draft Fact-Sheets: TWO draft fact-sheets that address two of the
three terms are attached for your review. The titles of the
draft fact-sheets are "Immobilization as Treatment" and
"Innovative Treatment Technologies."
As mentioned previously, a fact sheet on "Interim Actions"
is not included in this package since it is being developed
separately. That fact-sheet is entitled "Guide to Developing
Superfund No Action, Interim Action, and Contingency Remedy RODs"
and is scheduled to be issued in the spring of FY 1991. Also, a
draft fact-sheet entitled: "Principal Threat and Low Level Threat
Wastes11 has been developed and is being provided to the National
Superfund Risk Management Work Group for review prior to issuance
to the Regions.
OBJECTIVE
The overall objective of this initiative is to standardize
the use of these terms, so that we achieve greater consistency
when applying these terms to the Superfund remedy selection
process and are better able to communicate clearly to the public
the achievements of the Superfund program.
IMPLEMENTATION
This memorandum requests comments on the definitions of the
terms discussed in this memo and the two draft fact-sheets
attached. Comments are requested by April 26, 1991 and should be
sent to:
Randy Breeden (OS-220W)
U.S. EPA
401 M. Street, S.W.
Washington, D.C. 20460
or FAX (FTS 398-8389 or Commercial 703-308-8389)
Comments may be provided either as a formal written response or
as notes in the margins of the fact-sheets. Your recommendations
regarding other key terms requiring guidance or additional
information needs are also appreciated.
The Regions are requested to utilize the draft suggested
definitions and draft fact-sheets until final guidance is issued
this spring. You should work with your Headquarter's Regional
Coordinator if you need additional assistance in applying these
terms.
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NOTICE: The policies set out in this memorandum are
intended solely as guidance. They are not intended, nor can
they be relied upon, to create any rights enforceable by any
party in litigation with the United States. EPA officials
may decide to follow the guidance provided in this
memorandum, or to act at variance with the guidance, based
on an analysis of specific site circumstances. The Agency
also reserves the right to change this guidance at any time
without public notice.
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Attachments
cc: Paul Nadeau, Acting Director, HSCD (OS-220W)
Steve Luftig, Director, ERD (OS-210)
Walt Kovalick, Director, TIO (OS-110)
Sally Mansback, Acting Director, CED/OWPE (OS-510W)
Clem Rastatter, Director, 0PM (OW-240)
Superfund Branch Chiefs, Region I-X
Superfund Section Chiefs, Regions I-X
Russ Hyer, Director, OSW/WMD
Ben Blaney, Branch Chief, ORD/RREL/STD/TSB
National Superfund Risk Management Work Group
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DRAFT
United States Office of Publication 9380.3-05FS
Environmental Protection Solid Waste February 1991
Agency and Emergency
Response
INNOVATIVE TREATMENT TECHNOLOGIES
•Office of Emergency and Remedial Response
Hazardous Site Control Division Quick Reference Fact Sheet
OS-220W
The Environmental Protection Agency believes that it is
important to foster the development and implementation of
innovative treatment technologies, particularly those
technologies which offer the potential for comparable or superior
treatment performance or implementability, fewer adverse impacts,
or lower cost for similar performance. The National Oil and
Hazardous Substances Pollution Contingency Plan (NCP) promulgated
on March 8, 1990 encourages the evaluation of innovative
technologies in developing remedial alternatives. (40 CFR Section
300.430(a)(l)(iii)(E).)
The purpose of this guide is provide guidance on innovative
technologies such that the Agency can direct efforts towards
fostering the use of such technologies and can evaluate the
progress of the program towards these ends. This guide provide a
definition of "innovative treatment technology(ies)", examples,
guidance on treatability studies, and ROD documentation
requirements.
DB7HHNO INNOVATIVE TREATMENT TECHNOLOGIES
Innovative Treatment Technologies are those technologies
where limited available data on the performance and/or cost
inhibit their use for many Superfund types of applications.
Innovative treatment technologies are considered based on
the NCP expectations for these technologies (40 CFR
300.430(a) (1) (iii) (E)). That is to say, innovative
technologies are generally considered when they offer the
"potential for comparable or superior treatment performance
or implementability, fewer or lesser adverse impacts than
other available approaches, or lower costs for similar
levels of performance than demonstrated technologies."
Because of the general lack of available technologies we
anticipate that at many sites we will consider innovative
technologies.
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ANALYSIS OF DEFINITION AS XT APPLIES TO SUPERFUHD
The Superfund program's definition of innovative technologies
includes the following:
o "New" technologies that have been demonstrated at the
bench- or pilot-scale for a limited number of
applications, and
o "Demonstrated" or "available" technologies used in
various industries but for which limited data are
available for Superfund site applications.
Since the types of materials encountered at Superfund sites
(particularly soil and debris) differ from bulk waste generally
treated at RCRA facilities, technologies that are commonly
employed at a RCRA facility may be considered innovative for a
Superfund application.
Although the Agency has selected diverse remedial
alternatives for Superfund sites, our experience in the
application of these technologies is limited. Immobilization of
inorganics and incineration of organics are generally considered
proven technologies for which we have extensive experience.
However, we have limited experience with many other types of
treatment technologies which may be utilized to treat source
material. For these reasons, we consider all source control
alternative technologies, with the exception of immobilization of
most inorganics and incineration of most organics, to be
innovative at the present time.
There will be occasions where a demonstrated or proven
technology is used in a manner that constitutes an innovative
application. For example, incineration of a complex waste
containing materials for which we have limited experience (e.g.,
NOx generating compounds) or innovative applications or designs
also may warrant the inclusion of these technologies into the
category of innovative technology. The selection of an
innovative design for thermal treatment or immobilization is
expected to be an infrequent event. RODs should usually identify
a generic type of technology (e.g., thermal destruction) rather
than a specific design (e.g., rotary kiln) unless specific
conditions warrant such as selection. Immobilization of some
inorganic compounds (e.g., arsenic, hydrogen cyanide, chromium
VI) is considered less proven and also would fall into the realm
of innovative treatment.
With regard to ground-water remediation, most technologies
selected for ex-situ treatment of ground water have found common
usage in the waste water treatment industry and it is believed
that these are generally "available technologies" for many
Superfund applications. There are a few technologies, and
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hopefully there will be acre in the future, which are or will be
considered innovative technologies. In addition, treatment of
waste water treatment residuals also nay utilize many of the
technologies applicable to source material, and these also may be
considered innovative.
Conversely, all in-situ technologies for remediating ground
water and source material are considered innovative at this time.
We anticipate that the list of remedial alternatives which
are characterized as "innovative technologies" in the Super fund
program will change over time. Technologies will graduate to the
"available technology" category and new technologies will enter
the "innovative technology" category. As a result, an annual
analysis of Superfund progress will use a consistent definition
but the list of technologies that comprise that category will
change.
This definition does differ slightly from that which is used
in the Agency's Superfund Innovative Technology Evaluation (SITE)
program but we believe the differences are justified and should
not affect analysis conducted by either program. The SITE
program considers three stages of technology development:
(1) Available Alternative Technology - technologies that are
fully proven and routinely used at hazardous waste sites.
(2) Innovative Alternative Technology - any fully developed
technology for which cost or performance information is
incomplete, thus hindering routine use. An innovative
alternative technology requires field testing and evaluation
before it is considered proven and available for routine
use.
(3) Emerging Alternative Technology - a technology in an
earlier stage of development. Documentation has involved
laboratory testing, and the technology is being developed at
pilot-scale prior to field testing at Superfund sites.
For purposes of the Superfund program we have grouped the last
two categories under the tern "innovative technology." While the
Agency will primarily be selecting technologies which fall under
the first two categories of the SITE program, there may be
situations where an "emerging technology" may also be selected
based on developmental efforts conducted at a site. Therefore,
for purposes of the Superfund program there does not appear to be
a reason for maintaining a separate category for emerging
technologies for the Superfund program.
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EXAMPLES
Table 1 provides a list of treatment technologies which are
currently considered "innovative" or "available". The list is
not intended to be exhaustive. Most of the technologies listed
have been selected in Records of Decisions (RODs); a few
additional technologies have been listed because they are
believed to have a high potential of being applied to Superfund
sites. Other technologies are under development and are
innovative technologies. As these are selected as remedial
alternatives for Superfund sites they will be added to the list.
Table 2 provides a listing of treatment technology synonyms
which will aid in the use of Table 1.
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Table.1
CliXflaiyiCATIOM OF TREATMENT TECHNOLOGIES
Treatment technologies for source material are grouped based on
the primary function for which they are generally used:
destruction/detoxification, separation/recovery, immobilization,
and other.
INNOVATIVE
DESTRUCTION/DETOXIFICATION
Bioremediation
Composting
Solid-Phase Bioremediation
Slurry-Phase Bioremediation
Soil Heaping
Vacuum-Enhanced Bioremediation
In-Situ Bioremediation
Chemical Destruction
Dehalogenation
Dechlorination
Chemical Oxidation
Chemical Reduction
Thermal Destruction
Incineration (Organics in the presence of inorganics2)
1 The list is not all inclusive.
2 Thermal destruction technologies are generally considered
available for most organic wastes. Thermal destruction of
organic waste mixed with inorganics (e.g., metals, hydrogen
cyanide, nitrous oxide generating compounds) may be innovative if
it requires innovative engineering approaches to address
emissions problems and/or concerns regarding residuals
characteristics.
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Classification of Innovative Treatment Technologies for Treatment
of Source Material* (Continued)s
SEPARATION/RECOVERY
Chemical/Phvaical Extraction
Solvent Extraction
Soil Washing
In-Situ Vacuum Extraction
Soil Vapor Extraction (SVE)
Thermally-Enhanced Vacuum Extraction
In-Situ Soil Flushing
Thermal Desorption
Ex-Situ Thermal Desorption
In-Situ Steam Stripping
In-Situ Hot Air Stripping
IMMOBILIZATION9
Solidification/Stabilization (Organics and select
inorganics (e.g., Ar, HCN, Cr(VI))
Stabilization (Organics and select inorganics (e.g.,
Ar, HCN, Cr(VI))
In-Situ Solidification/Stabilization (All wastes)
In-Situ Stabilization (All wastes)
OTHER4
Ex-Situ Vitrification
In-Situ Vitrification
5 Immobilization is generally considered innovative when it
involves treatment of organics and/or treatment of inorganics
which include arsenic, hydrogen cyanide, or chromium(VI). This
is primarily due to uncertainty regarding the effectiveness of
the technology for these waste types.
4 The "Other" category includes technologies involving
multiple treatment functions (e.g., destruction and
immobilization), generally due to the presence of both organics
and metals in the source material.
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Classification of Available Treatment Technologies for Treatment
of Source Materialss
AVAILABLE*
DESTRUCTION/DETOXIFICATION
Thermal Destruction
Incineration (Oganics)
Rotary Kiln Incineration
Fluidized Bed Incineration
Liquid Injection Incineration
Infrared Incineration
IMMOBILIZATION (Most inorganics and metals)
Stabilization
Solidification/Stabilization
Sorbent Solidification
CLASSIFICATION OF TREATMENT TECHNOLOGIES
FOR TREATMENT OP AQUEOUS STREAMS*
Treatment technologies for aqueous streams are grouped based the
categories commonly used in the waste water treatment industry:
biological, chemical/physical treatment, and other.
INNOVATIVE
BIOLOGICAL
In-Situ Biodegradation for Ground Water
OTHER
All in-situ treatment methods applied to the saturated zone
for ground water remediation.
5 In some cases, modifications of available technologies
may be considered innovative.
6 The list is not all inclusive.
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8
Classification of Available Treatment Technologies for Treatnent
of Aqueous Btreaasi
AVAILABLE7
BIOLOGICAL
Activated Sludge
Aerobic Treatment
Fixed-film Reactors
Rotating Biological Contactors
Sequencing Batch Reactors
CHEMICAL/PHYSICAL TREATMENT
Air Stripping
Carbon Adsorption
Chemical Precipitation
Ion Exchange
Reverse Osmosis
Steam Stripping
Ultrafiltration
UV/Oxidation
7 In some cases, modifications of available technologies
may be considered innovative.
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Table 2
TREATMENT TECHNOLOGY flYKONYMS
A listing of preferred terns and commonly used synonyms are
provided below.
PREFERRED TERM SYNONYM
Destruction/Detoxification
Thermal Destruction Thermal Treatment8
Solid-Phase Bioremediation Land Farming
Land Treatment
Land Application
Contained Solid-Phase
Separation/Recovery
Solvent Extraction Critical Fluid Extraction
Carbon Dioxide Solvent
Extraction
Propane Solvent Extraction
Triethylamine Solvent
Extraction
Ex-Situ Thermal Desorption Enhanced Volatilization
Low-Temperature Desorption
Low Temperature Thermal
Treatment
Thermal Aeration
Thermally Enhanced
Volatilization
Soil Vapor Extraction (SVE) Vapor Extraction
In-Situ Volatilization
Soil Venting9
Immobilisation Fixation
8 Thermal Treatment has been used in the past to mean
either thermal destruction (e.g., incineration) or thermal
desorption (e.g., steam stripping).
9 Passive soil venting is also a means of ventilating
subsurface gases or vapors (such as methane) in the absence of a
vacuum. This type of soil venting is not considered treatment.
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10
TREATABILITY STUDIES
It la Agency policy that treatability studies will be
conducted during the remedial investigation/feasibility study
(RI/FS) when there are insufficient data to support the
evaluation choice of a treat remedy during the selection process.
This policy was provided in the directive entitled: "Advancing
the Use of Treatability Technologies for Superfund Remedies"
(OSWER Directive No. 9355.0-26, Feb. 21, 1989). The directive
points out the importance of treatability studies particularly
for "innovative technologies." The importance and need for
treatability studies was also identified in A Management Rev ley
of the Superfund Program (July 1989).
Treatability studies will be needed for the selection and
implementation of innovative treatment technologies except for
those situations where sufficient information is available for
the treatment technology for similar waste and waste matrix.
Currently this information does not exist for most treatment
technologies termed innovative. Treatability studies may also be
needed for the "available" treatment technologies where
insufficient data are available to support the remedy evaluation
and/or implementation.
Guidance for designing and executing treatability studies
is provided in the Guide for Conducting Treatability Studieq
under CERCLA. Interim Final, EPA 540/2-89/058, December 1989 and
in the Treatability Studies under CERCLA! An Overview. Quick
Reference Fact Sheet, Directive 9380/3-02FS, December 1989.
ROD DOCUMENTATION
The characterization of a treatment alternative as
"innovative" or "available" should be documented in the "Selected
Remedy" section of the ROD Decision Summary. The information
provided above together with knowledge about the technology and
site-specific information should be used to characterize
technologies.
The following information should be discussed in the
"Description of the Alternatives", "Summary of Comparative
Analysis of Alternatives" and the "Selected Remedy" sections of
ROD:
Identification of treatment alternative(s),
Characterization of the treatment technology as
innovative or available,
Supporting justification for those situations where a
technology is characterized differently from that
provided in the examples above.
Information on the media/waste type and volume which
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11
will be treated by the treatment technology,
Information on the performance and effectiveness of
treatability studies, and
References of treatability study(ies), if provided in
lieu of a site-specific study.
FOR FURTHER ZMFORNATXOK
The appropriate Regional Coordinator for each Region located
in the Hazardous Site -Control Division/Office of Emergency and
Remedial Response or the CERCLA Enforcement Division/Office of
Waste Programs Enforcement should be contacted for additional
information.
NOTICE: The policies set out in this memorandum are
intended solely as guidance. They are not intended, nor can
they be relied upon, to create any rights enforceable by any
party in litigation with the United States. EPA officials
may decide to follow the guidance provided in this
memorandum, or to act at variance with the guidance, based
on an analysis of specific site circumstances. The Agency
also reserves the right to change this guidance at any time
without public notice.
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DRAFT
United States Office of Publication 9380.3-07FS
Environmental Protection Solid Waste February 1991
Agency and Emergency
IMMOBILIZATION AS TREATMENT
Office of Emergency and Remedial Response
Hazardous Site Control Division Quick Reference Fact Sheet
Section 121(b) of CERCLA mandates the EPA to select remedies
that "utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the maximum
extent practicable" and to prefer remedial actions in which
treatment "permanently and significantly reduces the volume,
toxicity, or mobility of hazardous substances, pollutants, and .
contaminants as a principal element." Immobilization is one such
treatment technology which may find application at Superfund
sites to meet the CERCLA mandate for treatment. Since
immobilization is not generally considered a destructive or
removal treatment technology for which treatment effectiveness
can most easily be defined, it is important that the Agency
establish clear guidelines as to when and under what conditions
immobilization satisfies the CERLA mandate.
The purpose of this guide is to provide guidance on the
conditions under which immobilization is an appropriate treatment
technology under the Superfund program. This guide provides: a
definition of immobilization, the current Agency policy on the
use of immobilization for Superfund applications, the status of
the immobilization as it relates to the RCRA Land Disposal
Restrictions, and ROD documentation requirements.
DEFINITION OF IMMOBILIZATION
The term "immobilization" is used to mean any of the
technologies which limit the solubility or mobility of
contaminants. The term "fixation" has also been used as a
synonym for immobilization. Technology types which fall within
the realm of immobilization include:
Stabilization
Solidification/Stabilization
Sorbent Solidification
The various immobilization technologies limit solubility or
mobility with or without a change in physical characteristics of
the matrix. Immobilization may involve physical/chemical
processes that do more than simply entrap the contaminants.
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Solidification alone !• not included as a treatment
technology under the Superfund definition of immobilisation
because it does not satisfy the statutory preference for
treatment to reduce tae toxicity, mobility, or volume (TMV) under
Superfund. The term "solidification11 implies a treatment
technology which is intended to produce a monolith for purposes
of structural integrity. Since the principal purpose of
solidification is structural integrity, it does not qualify as
treatment under Superfund for purposes of .reduction of TMV.
Solidification performed in conjunction with stabilization (i.e.,
solidification/stabilization), however, would satisfy the
preference for treatment under Superfund and falls within the
Superfund program's definition of immobilization.
IMMOBILIZATION AS A TREATMENT ALTERNATIVE
Concerns have been raised regarding the types of
immobilization that provide for adequate protection. The
principal reason for these concerns rest on the fact that
immobilization is not generally considered a destructive
technique but rather prohibits or impedes the mobility of
contaminants.
Although experts are in general agreement regarding the
effectiveness of immobilization for most inorganics and metals,
the effectiveness of immobilization for organics cannot be
predicted without testing. Furthermore, the testing methods
available (i.e., leachability tests) provide different types of
information on the mobility of contaminants depending on the
test. For these reasons, Superfund has developed general
guidelines for evaluating and selecting immobilization taking
into consideration the testing methods currently available,
scientific understanding to date, and the NCP expectations
regarding treatment.
The preamble to the NCP (55 FR Page 8701, March 8, 1990)
provides the following guidance regarding treatment
e f fectiveness:
"...The Superfund program also uses as a guideline for
effective treatment the range 90 to 99 percent reduction in
the concentration or mobility of contaminants of
concern....EPA believes that, in general, treatment
technologies or treatment trains that cannot achieve this
level of performance on a consistent basis are not
sufficiently effective and generally will not be
appropriate."
The use of any treatment technology, including immobilization,
needs to be weighed against this policy and current knowledge
regarding the technology application.
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8UPBR*Un> POLICY OH USB OF IMMOBILIZATIOM
This guide provides Agency policy on the use of
immobilization for treatment in view of concerns that have been
raised regarding technology performance primarily for organics.
The Superfund policy is as follows:
Immobiliiation is generally appropriate as a treatment
alternative only for material containing inorganics, semi-
volatile and/or non-volatile organics. Based on present
information, the Agency does not believe that immobilization
is an appropriate treatment alternative for volatile
organics. Selection of immobilization of semi-volatile and
non-volatile organics generally requires the performance of
a site-specific treatability study or non-site-specific
treatability study data generated on waste which is very
similar (in terms of type of contaminant, concentration, and
waste matrix) to that to be treated and that demonstrates,
through Total Waste Analysis (TWA), a significant reduction
(i.e., a 90-99 percent reduction) in the concentration of
chemical constituents of concern1.
The need for treatability study data and the importance of
conducting appropriate leachability tests as part of the study,
are important parts of this policy statement. Treatability
studies to demonstrate the effectiveness of treatment of organics
is needed since we do not believe that we can predict the degree
of performance which may be provided without such testing.
Although immobilization has a long history of application for
inorganics, treatability testing may also be advisable for site
specific cases for both inorganics and organics constituents
where we have insufficient data.
EPA believes that .given the uncertainty associated with
immobilization of organics, the most stringent leachability test
available (i.e., TWA) should be used to demonstrated the
effectiveness of the technology. A successful demonstration
using TWA provides a measure of assurance regarding the
leachability of the organics. TWA does not mirror environmental
conditions, however, and does not provide information on the
protectiveness under specific management scenarios for the
immobilized product. One or more other leachability tests may
1 The 90-99 percent reduction in contaminant concentration
is a general guidance and may be varied within a reasonable range
considering the effectiveness of the technology and the clean-up
goals for the site. Although this policy represents EPA's strong
belief that TWA should be used to demonstrate effectiveness of
immobilization, other leachability tests may also be appropriate
in addition to TWA to evaluate the protectiveness under a
specific management scenario.
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also toe used in conjunction with TWA to ensure that the remedy is
protective and can meet the remediation levels for the site-
specific conditions.
Immobilization is not currently viewed as an effective
treatment method for volatile organics since these compounds will
be released during treatment as well as following treatment.
Alternative treatment methods should be evaluated to destroy or
remove the volatile organics to remediation levels either prior
to or concurrently with immobilization. A treatability study
will be needed to demonstrate the effectiveness of the
destruction or removal treatment technology through measurement^
of emissions,.
The Superfund policy on immobilization is based on current
knowledge with regards to immobilization effectiveness. This
policy may change in the future as we gain knowledge on the use
of immobilization and leachability testing.
POLICY ANALYSIS
The immobilization policy focuses principally on the
appropriate use of the technology as a treatment alternative.
The performance of the technology against site specific
remediation goals also needs to-be considered in the evaluation
of the treatment technology.
The policy is broken down into various components to clarify
when immobilization will and will not be considered to constitute
treatment to reduce TMV under Superfund:
Immobilisation generally constitutes treatment of wastes to
reduce TKV ia the following circumstances:
o Immobilization of inorganics.2
o Immobilization of semi-volatile and non-volatile
organics contaminants of concern where a treatability
study was performed during the RZ/FS or is planned
during the RD/RA, and the performance achieved or
performance goal is generally 90 percent reduction or
greater of the contaminant concentration or mobility
using TWA before and after treatment.
2 Treatability tests for immobilization of inorganic wastes
may be appropriate in situations where insufficient data is
available to support remedy selection or implementation.
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'0 Immobilization of semi-volatile and non-volatile
organics where non-site-specific data (treatability or
full scale operational data) are available for similar
wastes (in terms of contaminants, concentration, and
waste matrix), and the performance achieved was
generally 90 percent reduction or greater in the
concentration or nobility of contaminants of concern
using a TWA before and after treatment. The reference
for the treatability study report and a discussion of
the data applicability at this site was provided.
Immobilisation is not deemed to constitute treatment to
reduce TM7 in the following circumstances:
o Immobilization of volatile organics.3
o Immobilization of semi-volatile and non-volatile
organics where a treatability study producing data
meeting the above criteria is not performed, planned
and/or referenced.
ANTICIPATED APPLICATIONS OF IMMOBILIZATION
Immobilization is most commonly accepted as an appropriate
remedy for wastes which contain only inorganics or high levels of
inorganics in combination with semi- and/or non-volatile organics
which would not in themselves result in a waste being deemed a
principal threat. For example, a waste may contain elevated
levels of lead and -a low-level concentration of a relatively
immobile organic (e.g. PCBs). In such a case one could
immobilize the waste for the metal but the organic might not be
targeted for treatment since it is at levels at which engineering
controls would be more appropriate. A treatability study for the
organics would not be needed unless we were attempting to achieve
a significant degree of treatment (e.g., 90 percent or greater
reduction in mobility) for purposes of protectivcness. A
treatability study would need to be conducted, if the organics
were of concern and immobilization was being used to treat those
constituents. A treatability study would also be needed for the
inorganics if insufficient information is available to support
the remedy decision for these constituents.
5 This general statement does not apply to carbon
adsorption of volatile emissions which is followed by carbon
regeneration or treatment. Carbon adsorption has found wide
acceptance for volatile organic control from air emission sources
and waste water treatment facilities.
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Although treatment of high levels of organics may be
achievable with immobilization, the Agency is recommending that
alternative treatment technologies be evaluated in addition to
immobilization, or that treatment trains (which combine pre-
treatment or concurrent treatment to destroy or remove the
organics together with immobilization) be evaluated. Treatment
technologies which have found application to organic wastes
include destructive or removal technologies such as thermal
destruction, thermal desorption, solvent extraction, etc. If
pre-treatment or concurrent treatment is evaluated to address the
organics, the technology should generally be able to achieve a
significant reduction of the organics constituents (i.e., 90
percent reduction or greater or a level that is deemed protective
under the reasonably expected use scenarios).
Since immobilization is not currently considered a viable
treatment alternative for volatile organic materials, an
alternative treatment method to immobilization (i.e., use of a
pre-treatment or concurrent treatment method) should be used to
remove or destroy the volatile organics to remediation levels.
Treatability study data are required to demonstrate the
destruction or removal of the volatile organics to these levels.
EXAMPLES
Examples of immobilization which constitute treatment:
o The waste matrix contains inorganics at concentrations
that represent a principal threat and high molecular
weight organics that are low-level threat wastes since
they are near above unrestricted use levels and are
relatively non-mobile under the current and future
environmental conditions. The disposal of the
treatment product would generally require engineering
controls since the organics would generally be above
levels of concern. Selection of immobilization would
constitute treatment to reduce TMV for the inorganic if
it Bet the remediation goals for the inorganics since
the waste warrants treatment solely due to the presence
of inorganics.
o The waste matrix contains mobile semi- and non-volatile
organics at concentrations that represent a principal
threat. A treatability study is conducted that shows
that the concentration or mobility of the organics is
reduced 90 percent or greater by using TWA before and
after immobilization. The treatability study is
documented in the ROD. Immobilization of the organics
constitutes treatment to reduce TMV since a
treatability study verified its probable performance
which was documented in the ROD.
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•9 The wast* matrix contains inorganics at levels deemed
appropriate for treatment (i.e., principal threat) and
seal- and non-volatile organic contaminants at levels
deemed appropriate for containment (i.e., low-level
threat). Treatment of the both types of wastes is
selected based on economies of scale (cost
effectiveness) and treatability study data which
demonstrate a 90 percent reduction in the concentration
or nobility for both inorganics and organics of
concern. Immobilization of the organics and inorganics
constitutes treatment to reduce TMV because a
treatability study was conducted and documented showing
effective treatment of the organics.
Examples of immobilizations which generally do not
constitute treatment to reduce TMV:
o The waste matrix contains inorganics that due to
mobility and concentration result in the waste matrix
being deemed a principal threat and volatile organics
which result in emissions above levels that are
protective. Immobilization- would generally count as
treatment to reduce TMV for the inorganics but not for
the volatile organics which would volatilize during the
immobilization process and may continue to volatilize
after completion of the remedy. Pre-treatment to
remove or destroy the volatile organics to remediation
levels established in the ROD is generally required.
o The waste matrix contains mobile semi- and non-volatile
organics at levels which constitute a principal threat.
A treatability study was not conducted, treatability
study data of similar waste was not documented in the
ROD, and a treatability study is not planned post-ROO.
Immobilization would generally not constitute treatment
to reduce) TMV in this situation since the waste
warrant* treatment due to the presence of the organics
and a treatability study was not performed, planned, or
documented.
RCRA UUO DISPOSAL RESTRICTIONS
CERCLA remedial actions must comply with the requirements of
the Resource Conservation and Recovery Act (RCRA) when they are
determined to be applicable or relevant and appropriate
requirements (ARARs) unless a waiver is justified. Potential
ARARs for CERCXA responses include the RCRA land disposal
restrictions (LDRs) established under the Hazardous and Solid
Waste Amendments (HSWA). The LDRs prohibit the land disposal of
restricted RCRA hazardous wastes unless these wastes meet
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treatment standards specified in 40 CFR Part 268, meet the
minimum technology requirements during a national treatment
capacity extension, or satisfy the requirements of one of the
other available compliance options (i.e., treatability variance,
equivalent treatment method, no migration demonstration, or
delisting).
While immobilization may be treatment to reduce TMV, it may
not be able to comply with the LDRs, which are based on best
demonstrated available technology (BOAT). In setting BOAT, the
Agency can decide that BOAT involves destroying or recovering the
hazardous constituents, or that decreasing the mobility
represents BOAT. To date, immobilization has been selected as
BOAT only for metals. Immobilization is not generally
appropriate for compliance with existing BOAT standards for
organics (40 CFR Part 268.43) because it serves to dilute the
waste, lower the effectiveness of the analytical method, and not
significantly lower the amount of hazardous constituents present.
Immobilization of organics does have a role in the
treatability variance process for contaminated soil and debris.
The fact sheet entitled: Superfund LDR Guide »6A f2nd Edition)
Obtaining a Soil and Debris Treatability Variance for Remedial
Actions. Superfund Publication 9347.3-06FS, September 1990 should
be consulted for guidance on applying this variance.
The evaluation method specified in Superfund LOR Guide ISA
for the immobilization of organic waste (first foot-note on page
two) has changed since the issuance of the guidance. The
September 1990 guidance specified the "TCLP method" but should
read TWA. The revised foot-note should read:
"TWA should be used when evaluating wastes with relatively
low levels of organics that have been treated through
immobilization."
As stated previously, TWA is believed to provide a more stringent
test of the immobilization and the potential degree of chemical
interaction which may have occurred.
The treatability variance guidance for soil and debris (as
modified above) will apply on a case-by-case basis until final
LDR soil and debris standards are issued.
ROD OOCUMBMTATZOM
The Record of Decision (ROD) should indicate clearly what
materials are targeted for treatment by immobilization and the
rationale that supports the selection of immobilization. The
following information should be provided in the ROD for
immobilization to be characterized as treatment to reduce TMV:
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o Type of waste (i.e., non-volatile organics, semi-
volatile organics, volatile organics, or inorganics),
o Constituents in the waste to be remediated by
immobilization,
o Treatability study results (literature reference and
results of site-specific studies) which demonstrate 90
percent reduction or greater in contaminant
concentration or mobility using TWA.
o Treatability study results that demonstrate the
effectiveness of immobilization to achieve remediation
levels.
This information should be provided in the "Selected Remedy11
section of the ROD Decision Summary to ensure that it is
documented appropriately. This information also should be
provided in the "Description of the Alternatives", "Summary of
comparative Analysis of Alternatives" and the "Selected Remedy"
sections of ROD. Please refer to the Interim Final Guidance on
Preparing Superfund Decision Documents (OSWER Directive 9355.3-
02, November 1989) for additional information on ROD
documentation.
FOR FURTHER XHFORJOtTXOV
The appropriate Regional Coordinator for each Region located
in the Hazardous Site Control Division/Office of Emergency and
Remedial Response or the CERCLA Enforcement Division/Office of
Waste Programs Enforcement should be contacted for additional
information.
NOTICE: The policies set out in this memorandum are
intended solely as guidance. They are not intended, nor can
they be relied upon, to create any rights enforceable by any
party in litigation with the United States. EPA officials
may decide to follow the guidance provided in this
memorandum, or to act at variance with the guidance, based
on an analysis of specific site circumstances. The Agency
also reserves the right to change this guidance at any time
without public notice.
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