&EPA
United States
Environmental Protection
Agency
Office of Emergency and
Remedial Response
Washington, DC 20460
EPA 540-R-97-029
October 1997
Implementing
Presumptive
Remedies
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WHAT'S IN THIS PRESUMPTIVE REMEDY NOTEBOOK
Superfund's extensive experience in complex toxic waste site cleanup has revealed certain
consistencies in site characteristics and remedies. Some categories of sites have similar
characteristics, such as types of C9ntaminants present, past industrial use, or environmental media
affected. The "presumptive remedy" initiative looks for remedies that are appropriate for specific
site types and/or contaminants. Its objective is to use the program's past experience to streamline site
investigations and make remedy selection speedier and more predictable. The five types of sites for
which there is (or soon will be) presumptive remedy guidance are:
* VOCs in Soils ^ Wood Treaters
•> Municipal Landfills > Contaminated Ground Water
> Metals in Soils (scheduled for early FY98
release)
So, what are the advantages of using the presumptive remedies? They offer several advantages over
the conventional remedy selection process. Presumptive remedies:
+ Save time and money — At municipal landfills implementing the containment presumptive
remedy, for example, EPA estimates time savings ranging from 36 to 56 percent, and cost
savings up to 60 percent resulting from a streamlined remedial investigation/feasibility study
process.
* Help promote consistency in the remedy selection — Ensures that similar remedies are used
for similar types of contamination and allows cross-site comparisons, which ultimately
minimizes the time involved in remedy selection decisions.
* Improve the predictability of the remedy selection process for communities and PRPs
Allows interested parties to review previous actions taken at similar sites—increasing their
comfort level in accepting the selected remedy and hastening the selection process.
4 Take no extra time or effort — The steps you must follow to implement a presumptive remedy
are aspects of your daily job duties. In other words, these savings can be achieved without
increasing your workload, and they may even streamline your workload.
* Are supported by experts — RPMs can access presumptive remedy experts that will be able to
provide support and information to assist you during implementation.
* Are NCP compliant — The use of presumptive remedies advances the NCP remedy selection
objectives in that they promote consistency in decision-making and carry out the screening step
in a generic manner. This approach minimizes the steps needed to perform this analysis at a
site-specific level.
October, 1997
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Presumptive remedies are also Superfund policy. EPA guidance states that presumptive remedies are
expected to be used at all appropriate sites, except under unusual site-specific circumstances. This
means that RPMs working at the types of sites represented in this notebook should investigate the
possibility of implementing a presumptive remedy.
This notebook contains the current guidance, users guides, and supplemental information available
on specific presumptive remedies, including names and numbers of colleagues you can call for
advice. Contents include:
Chapter 1 — Three general fact sheets on presumptive remedies including one that can be used to
help explain the benefits to communities, and a presumptive remedies directive from
Richard Guimond.
Chapter 2 — VOCs in Soils and related information
Chapter 3 — Municipal Landfills and related information
Chapter 4 — Wood Treaters and related information
Chapter 5 — Contaminated Ground Water and related information
Chapter 6 — Administrative Record Requirements and related information
An annotated table of contents follows this introduction which contains a brief description explaining
each of the documents in the notebook. The notebook will be updated periodically as new
information or guidance becomes available; new chapters will be added as appropriate.
Presumptive remedies are not new. EPA has been using them since 1993. To date, presumptive
remedies have been used or are being used at 48 Superfund sites, and more than 80 operable units,
across the country. The chart on the following page provides a list of Regional contacts available to
assist EPA staff in implementing presumptive remedies.
In short, EPA expects that the use of presumptive remedies will streamline cleanup actions while
improving consistency, reducing costs, and speeding remediation. This notebook will provide you,
the RPM, with all the tools necessary to implement a presumptive remedy at your site.
October. 1997
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PRESUMPTIVE REMEDIES REGIONAL CONTACTS
(current as of August 1 , 1 997)
REGION
I
II
III
IV
V
VI
VII
VIII
IX
X
CONTACT
Mike Nalipinski
Mel Hauptman
Paul Leonard
Felicia Barnett
Dion Novak
Cathy Gilmore
Diana Engemann
Victor Kettelapper
Sean Hogan
Keith Rose
PHONE NUMBER
(617)223-5503
(212)637-3952
(215)597-3163
(404) 562-8659
(312)886-4737
(214)665-6766
(913)551-7746
(303)31^6578
(415) 744-2334
(206)553-7721
PRESUMPTIVE REMEDIES HEADQUARTERS CONTACTS
(current as of August 1, 1997)
PRESUMPTIVE REMEDY
Contaminated Ground Water
Municipal Landfills
Wood Treaters
Metals in Soils
VOCs in Soils
HEADQUARTERS
CONTACT
Ken Lovelace
Andrea Mc'Laughlin
Frank Avvisato
Richard Jeng
John Blanchard
PHONE NUMBER
(703) 603-8787
(703)603-8793
(703) 603-8949
(703)603-8749
(703)603-9031
October, 1997
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October, 1997 4
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Annotated Table of Contents
General Material
1. A Citizen's Guide to Understanding Presumptive Remedies (October 1997), This fact
sheet, written for a public audience, provides answers to general questions regarding
presumptive remedies. Assumes basic Superfund knowledge. EPA 540-F-97-019
2. Presumptive Remedies: Policy and Procedures (September 1993). Written in Q&A
format, this fact sheet serves as an overall guide to the presumptive remedies initiative and its
effect on site cleanup. It also explains how presumptive remedies will streamline or change the
remedial and removal processes and how certain Superfund policies will be affected by the
initiative. EPA 540-F-93-047
3. Superfund Accelerated Cleanup Bulletin: Presumptive Remedies (August 1992).
This short bulletin, written at the outset of the presumptive remedies initiative, describes
Superfund efforts for developing presumptive remedies for various types of sites including
Municipal Landfill Sites, Wood Treatment Sites, Solvent Sites, and Ground Water Sites.
Publication 9203.1-021
4. Presumptive Remedies Directives: Memo from Richard Guimond (September 1993).
This four page memo provides a brief history on the development of presumptive remedies,
explains the objectives of the presumptive remedy guidance including when they are expected
to be used.
VOCs in Soils
1. Presumptive Remedies: Site Characterization and Technology Selection for CERCLA
Sites With Volatile Organic Compounds in Soils (September 1993). This fact sheet
identifies the presumptive remedies for CERCLA sites with soils contaminated by volatile
organic compounds (VOCs). EPA 540-F-93-048
2. User's Guide to the VOCs in Soils Presumptive Remedies (July 1996). This user's guide is
based on the VOCs in soils, presumptive remedy guidance, Presumptive Remedies; Site
Characterization and Technology Selection for CERCLA Sites With Volatile Organic
Compounds in Soils, and includes recommendations on the preferred presumptive remedy for
sites where VOCs are present in soil and treatment is warranted. EPA 540-F-96-008
Implementing Presumptive Remedies: Octpber, 1997
A Notebook of Guidance and Resource Materials
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3. Presumptive Remedy: Supplemental Bulletin Multi-Phase Extraction (MPE)
Technology for VOCs in Soil and Ground Water (April 1997). This fact sheet serves as an
ancillary to the guidance on presumptive remedies for VOCs in soils and provides information
on the Multi-Phase Extraction (MPE) technology for extraction of VOCs present in soil and
ground water. This fact sheet recommends MPE as a technology option under the VOCs
presumptive remedy. EPA 540-F-97-004
Municipal Landfills
1. Presumptive Remedy for CERCLA Municipal Landfill Sites (September 1993).
This fact sheet describes presumptive remedies for municipal landfills and recommends
containment as the presumptive remedy for such sites. This directive also highlights the
importance of certain streamlining principles related to the scoping (planning) stages of the
remedial investigation/feasibility study (RI/FS). EPA 540-F-93-035
2. Landfill Presumptive Remedy Saves Time and Cost (January 1997). This bulletin
summarizes the results of implementing the containment presumptive remedy at three
CERCLA municipal landfill sites, including details on the achieved time and cost savings.
EPA540-F-96-017
3. Application of the CERCLA Municipal Landfill Presumptive Remedy to Military
Landfills (December 1996). This fact sheet discusses the application of the CERCLA
Municipal Landfill presumptive remedy to military landfills. It also highlights a step-by-step
approach to determining when a specific military landfill is an appropriate site for application
of the containment presumptive remedy. EPA 540-F-96-020
4. Superfund Accelerated Cleanup Bulletin: Presumptive Remedies for Municipal Landfill
Sites (Volume 1 Number 1, April 1992). This bulletin describes the kick-off of Municipal
Landfill Pilot Projects to expedite site investigation and remedy selection process for
municipal landfills. Publication 9203.1-021
5. Superfund Accelerated Cleanup Bulletin: Presumptive Remedies for Municipal Landfill
Sites (Volume 2 Number 1, February 1993). This bulletin describes the Municipal Landfill
Pilot Project and provides key findings from the pilots completed as of the date of publication
(four site visits), particularly with respect to the level of detail that was appropriate for
establishing risk at two of the sites. Publication 9203.1-021
6. Presumptive Remedies: CERCLA Landfill Caps RI/FS Data Collection Guide (August
1995). This fact sheet identifies the data pertinent to landfill cap design that will be required
for most sites. These data are organized within six categories: (1) waste area delineation; (2)
slope stability and settlement; (3) gas generation/migration; (4) existing cover assessment; (5)
surface water run-on/run-off management; and (6) clay sources. EPA 540-F-95-009
Implementing Presumptive Remedies: ,, October, 199
A Notebook of Guidance and Resource Materials
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7. Conducting Remedial Investigations/Feasibility Studies for CERCLA Municipal
Landfill Sites (February 1991). This streamlining manual presents the framework for the
presumptive remedy for CERCLA Municipal Landfill sites and details those principles related
to the scoping (planning) stages of the remedial investigation/feasibility study (RI/FS). This
document is not contained in this notebook but is a worthwhile source for more detailed
information. This document is available for a fee at: National Technical Information Center
(NTIS) U.S. Department of Commerce 5285 Port Royal Road Springfield, VA 22161 (703)
603-8919. OSWER Directive 9355.3-11,Publication 91-921205
Wood Treaters
1. Presumptive Remedies for Soils, Sediments, and Sludges at Wood Treater Sites
(December 1995). This directive provides guidance on selecting a presumptive remedy or
combination of presumptive remedies for wood treater sites with contaminated soils,
sediments, and sludges. EPA 540-R-95-128
2. Superfund Accelerated Cleanup Bulletin: Presumptive Remedies for Wood Treatment
Facilities (May 1992). This bulletin describes the presumptive remedy selection initiative as
it relates to wood treatment sites and provides a general overview of recommended
presumptive remedies for such sites. Publication 9203.1-021
3. Technology Selection Guide for Wood Treater Sites (May 1993). This fact sheet presents
information on technology performance for wood treater sites and is intended for use by a
decision-making team experienced with wood treater sites. EPA 540-F-93-020
4. Feasibility Study Analysis and Administrative Record for Wood Treater Presumptive
Remedy: Memo from Thomas Sheckells (July 1997). This memo transmits for Regional
use the Administrative Record documents supporting the policy directive entitled
"Presumptive Remedies for Soils, Sediments, and Sludges at Wood Treater Sites." The actual
administrative record is fairly large and is being forwarded to the presumptive remedies
administrative records contacts listed in Attachment A. Attachment B provides a list of
Presumptive Remedies Workgroup Members, and Attachment C contains a general guide on
the presumptive remedies Administrative Record.
Contaminated Ground Water
1. Presumptive Response Strategy and Ex-Situ Treatment Technologies for Contaminated
Ground Water at CERCLA Sites (October 1996). This guidance emphasizes the
importance of using site-specific remedial objectives as the focus of the remedy selection for
contaminated ground water and recommends a presumptive response strategy for all sites with
contaminated ground water. This guidance is available on the Internet at:
http://www.epa.gov/superfund/index.htmttproducts. EPA 540-R-96-023
Implementing Presumptive Remedies: . October, 1997
A Notebook of Guidance and Resource Materials
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Administrative Record Requirements
1. Presumptive Remedies and NCP Compliance: Memo from James Costello (June 1995).
This memorandum explains the relationship of EPA's presumptive remedies initiative for
CERCLA site remediation ,to the requirements of the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP), 40 CFR Part 300. In addition, this document suggests
methods for meeting the NCP administrative record requirements for Superfund sites where
presumptive remedies are considered.
2. Feasibility Study Analysis and Administrative Record for Presumptive Remedies: Memo
from David Bennett (September 1994). This memo provides a general guide on the
presumptive remedies Administrative Record and is intended to assist Regional staff in
understanding the administrative record documents and site-type directives for supporting
presumptive remedies at individual sites.
Implementing Presumptive Remedies: October, 1997
A Notebook of Guidance and Resource Materials
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United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Directive No. 9378.0-1 IPS
EPA 540-F-97-019
PB97-963303
October 1997
A Citizen's Guide
to Understanding
Presumptive Remedies
Office of Emergency and Remedial Response
5202G
Cleaning up abandoned hazardous waste sites has been the charge of EPA's Superfund program since 1980.
Over the past 17 years, Superfund has gained considerable experience on hazardous waste cleanup
approaches and technologies. As we gained experience, we found that certain sites have similar
characteristics that we could use to our advantage to improve the cleanup process. The "presumptive remedy"
initiative is one of the results. Essentially, we said: "Here's a site similar in all key ways to many other sites we've
cleaned up. Wouldn't it make sense to use that cleanup approach here, too?"
Presumptive remedies benefit both Superfund and you—the community members affected by a Superfund site.
Keep reading to find the answers to questions you may have about presumptive remedies, how they work, and
why we use them.
1,?, 'What are presumptive remedies?
.As Superfund worked through hundreds of cleanups, we
-discovered similarities. Certain types of sites, like wood
', treater sites, have similar chemical contaminants. Other
sites, like municipal landfills, share similar charac-
teristics. At similar sites, standard remedies (called
"presumptive") can be applied. Presumptive remedies are
based on historical patterns of remedy selection and our
scientific and engineering evaluation of how well cleanup
technologies perform. EPA now expects presumptive
" remedies to be considered at all applicable sites. And they
should—those applicable sites make up more than 60% of
sites on the National Priorities List!
2., jWhy use presumptive remedies?
-•• Presumptive remedies have helped us streamline the
cleanup process. This approach has led to many
advantages, for you and for Superfund. When we first
investigate a site, we try to decide whether it is a
candidate for a presumptive remedy. If it is, then we can
narrow down the cleanup choices. This could save us a lot
of time in site investigation and data coljection efforts.
More importantly, it means that we spend less time in
your community, so there are fewer disruptions. And,
since the presumptive remedies have been successfully
implemented at other sites, you can be confident that it
will fully protect your health and your community's
environment.
One of the most important advantages is that, the sooner
your community knows the remedy, the sooner you can
plan for how you may want to use the site once it's cleaned
up. We can work with your local land planning group to
help determine how the community would like to use the
cleaned up site. Finally, some sites that have used
presumptive remedies have shown significant time and cost
savings. The more time and money we save at a site, the
more resources we have available to clean up other sites.
3. What are the different types of presumptive remedies?
Presumptive remedies have been developed for four kinds
of sites: municipal landfills, volatile organic chemicals
(VOCs) in soils, wood treater sites, and contaminated
ground water. Presumptive remedies can be grouped by the
type of cleanup plan: containment, treatment, and response
strategy. "Containment" holds the waste and prevents the
spread of contaminants. 'Treatment" uses a single
technology or group of technologies to get rid of the
contaminants. A "response strategy" is a long-term
approach with several steps and options to decide among
treatment and containment options for different sections of
a site. '
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4. What is the presumptive remedy for municipal
landfills?
The presumptive remedy for municipal landfills is
containment, which can include some or all of the
following components, as appropriate, on a site-specific
basis: landfill cap, to minimize infiltration of rain water
through the buried waste and to ground water below;
leachate collection and treatment; source area ground
water control to contain plume; landfill gas collection
and/or treatment; and institutional controls to ensure that
the integrity of the landfill cap is preserved.
5. What is the presumptive remedy for a site with VOCs
in the soils?
We have three presumptive remedy technologies to treat
a site with soils contaminated with VOCs. The preferred
remedy is soil vapor extraction. With this method, we
can leave the soil in place and remove contaminants with
a process that forces air through the soil. The other
choices are thermal desorption and incineration. Both of
these technologies require us to excavate the soil and
treat it with a process using heat. Once the soil is treated,
cleaned, and tested, we can return it to the site.
6. What is the presumptive remedy for a wood treater
site?
The presumptive remedy for a wood treater site depends
on the types of contaminants located at the site. If the
contaminants are organic, we use bioremediation,
thermal desorption, or incineration. If they are inorganic,
we use immobilization. Bioremediation is a natural
process that uses microorganisms, such as bacteria,
fungi, or yeast, that "eat" harmful contaminants and
transform them into nonhazardous products. Thermal
desorption and incineration are the same tecnnologies
described above to treat VOCs in soils. Immobilization
does not treat the contaminants, but rather prevents them
from spreading. This process mixes the hazardous
substances with chemicals and cement-like materials to
bind them and makes them immobile and inactive.
7. What is the presumptive remedy for a site with
contaminated ground water?
We use a response strategy to address sites with
contaminated ground water. This means we take a phased
approach to characterize and clean the site. Information
from each sequence of steps, or phase, helps us to
improve future investigations or actions. Basically, this
presumptive remedy helps us with the process of selecting
a remedy rather than choosing a particular remedy.
8. Couldn't this "cookie cutter" approach overlook
special problems at my site?
No. Presumptive remedies are meant to improve the
remedy selection process, not undermine it. Our site
investigation professionals use their expertise to
examine every site carefully. EPA is committed to the
best and the safest cleanup for every community. And
Superfund understands your community's need to find a
unique solution to your unique problems. You can rest
assured that when a full-length investigation of the
remedy alternatives is considered necessary, we will
doit.
9. Can the community ask EPA to consider other
cleanup alternatives?
Your voice will be heard! Communities are full partners
in the remedy selection process. If residents request it,
we will consider investigating other cleanup approaches
even if a presumptive remedy exists, or give you a full
explanation of why the presumptive remedy was
selected. We will assess each suggested alternative on its
own merits, and may proceed with further studies.
Presumptive remedies still add value even if we include
other approaches. Presumptive remedies provide a
baseline for protecting human health and the
environment; if we consider other specific cleanup
alternatives, they add additional layers of protection.
For more information about each presumptive
remedy, see the box titled "For Further Reading."
For Further Reading
The following documents are available at:
National Technical Information Service (NTIS)
(703) 487-4650 (800) 553-NTIS (rush service only)
. VOCs in Soil, EPA 540F-93-048/PB93-963346
. Municipal Landfills, EPA 540-F-93-035/PB93-963339
Wood Treater Sites, EPA 540/R-95/128 PB-963410
Ground Water Strategy, EPA 540/R-96/023 PB96-963508
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United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Directive: 9355.O-47FS
EPA 540-F-93-047
PB 93-963345
September 1993
Presumptive Remedies: Policy
Procedures
Office of Emergency and Remedial Response
Hazardous Site Control Division 5203G
Quick Reference Fact Sheet
Since Superfund's inception in 1980, the remedial and removal programs have found that certain categories of sites have
similar characteristics, such as types of contaminants present, types of disposal practices, or how environmental media are
affected. Based on information acquired from evaluating and cleaning up these sites, Superfund is undertaking an initiative
to develop presumptive remedies to accelerate future cleanups at these sites. The presumptive remedy approach is one tool
of acceleration within the Superfund Accelerated Cleanup Model (SACM).
The objective of the presumptive remedies initiative is to use the program's past experience to streamline site investigations
and speed up selection of cleanup actions. Over time presumptive remedies are expected to ensure consistency in remedy
selection and reduce the cost and time required to clean up similar types of sites. Presumptive remedies are expected to
be used at all appropriate sites except under unusual site-specific circumstances. EPA plans to develop a series of directives
i presumptive remedies for various types of sites.
This directive serves as an overall guide to the presumptive remedies initiative and its effect on site cleanup. Through a
question and answer format, it explains, in general terms, ways in which presumptive remedies will streamline or change
the remedial and removal processes from the conventional processes and how certain Superfund policies will be affected
by the initiative. This directive also unites the series of directives, due to come out over the next year, on presumptive
remedies for specific site types (e.g.. Volatile Organic Compounds (VOCs), wood treaters. ground water). This general
directive, together with the site type-specific directives, will provide readers with a comprehensive knowledge of the
procedural as well as policy considerations of the presumptive remedies initiative. The directive is designed foruse by staff
involved in managing site cleanups (e.g.. Remedial Project Managers (RPMs). On-Scene Coordinators (OSCs). Site
Assessment Managers (SAMs)). Site managers in other programs, such as RCRA Corrective Action, the Underground
Storage Tank program. State Project Managers, or private sector parties, may also use this directive, as appropriate.
Provided below are several common questions and answers
regarding general issues associated with presumptive
remedies. • •
Q1.
A.
What Are Presumptive Remedies and
How Should They Be Used?
Presumptive Remedies are preferred technologies
for common categories of sites, based on historical
patterns of remedy selection and EPA's scientific
and engineering evaluation of performance data on
technology implementation. EPA has evaluated
technologies that have been consistently selected at
past sites using the remedy selection criteria set out
in the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP); reviewed
currently available performance data on the
application of these technologies; and has
determined that a particular remedy, or set of
remedies, is presumptively the most appropriate
for addressing specific types of sites.
Presumptive remedies are expected to be used
at all appropriate sites. The approaches described
in each presumptive remedies directive are designed
to accommodate a wide range of site-specific
circumstances. In somecases, multiple technologies
are included (e.g.. VOCs); in others, various
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components of the presumptive remedy are optional.
depending on site situation (e.g.. municipal
landfills). Further, these directives recognize that
at some sites, there may be unusual circumstances
(such as complex contaminant mixtures, soil
conditions, or extraordinary State and community
concerns) that may require the site manager to look
beyond the presumptive remedies for additional
(perhaps more innovative) technologies or remedial
approaches.
These tools will help site managers to focus data
collection efforts during site investigations (e.g..
remedial investigations, removal site evaluation)
and significantly reduce the technology evaluation
phase (e.g.. Engineering Evaluation/Cost Analysis
(EE/C A) and/or Feasibility Studies (FS)) for certain
categories of sites. The specific impacts on the
various stages of the remedy selection process are
highlighted in questions 7 and 8 of this guidance. It
is advised that presumptive remedies be used with
the assistance of the expert teams' for the various
categories of sites.
Q2. Why Should Presumptive Remedies Be
Used?
Presumptive remedies are expected to have several
benefits. Limiting the number of technologies
considered should promote focused data collection.
resulting in streamlined site assessments and
accelerated remedy selection decisions which
achieve time and cost savings. Additional time
savinas could be realized during the remedial design
since^early knowledge of the remedy may allow
technology-specific data to be collected upfront
during the remedial investigation (RI). Presumptive
remedies will also produce the added benefit of
promoting consistency in remedy selection, and
improving the predictability of the remedy selection
process for communities and potentially responsible
panics (PRPs).
Presumptive remedies may be used as pan of a
wide variety of response actions. These actions
include non-time-critical removal and early
remedial actions, actions at sites with different
leads (e.g.. Fund-lead. State-lead. PRP-lead). actions
addressing one or more contaminated media, actions
with several operable units, and actions involving
treatment trains.
Q3. Can Presumptive Remedies be
Implemented Within the Existing NCP
Process?
Yes. The presumptive remedy approach is
consistent with all of the requirements of the NCP.
and in particular the site management principle of
streamlining (see section 300.43(Xa)( 1 )(")(C)). The
presumptive remedy approach simply consolidates
what have become the common, expected results of
site-specific decision making at Superfund sites
over the past decade. The various presumptive
remedies directives and supporting documentation
(e.g.. "Feasibility Study Analysis for CERCLA
Sites with Volatile Organic Compounds in Soils")
provide the basis for an adra inistrati ve record which
justifies consideration of a very limited number of
cleanup options. These materials summarize the
findings of EPA's research and analysis, and the
reasons that were found for generally considering
certain technologies more or less appropriate.
The availability of presumptive remedies does not
preclude a Region from expanding the FS (either
on its own initiative or at the suggestion of outside
parties) toconsiderothertechnologies underunusual
site-specific circumstances. The site type directives
will define the kind of circumstances (e.g.. soil
conditions, heterogeneous and complicated
contamination mixtures, field tests demonstrating
significant advantages of alternate or innovative
technologies, etc.) that may make presumptive
remedies less clearly suited for particular sites.
Most of these directives also provide references to
additional technologies if the presumptive remedies
are found not to apply at a particular site.
Q4. How Did the Presumptive Remedies
Initiative Evolve?
A. The general concept of presumptive remedies was
first V°P°sed in 199° dunng the Superfund 90-
Day Study and subsequently in 1991 during the
30-Day Study as a method of accelerating the
remedial process. These management studies
were efforts to generate options for accelerating
the overall Superfund clean-up process. The
presumptive remedies initiative is also consistent
with, and supports, a larger program initiative
known as the Superfund Accelerated Cleanup
1 It is envisioned 'that for most categories of sites, teams of experts (technical, legal, policy, etc.) who have developed the
presumptive remedies guidance and Regional site managers conducting field demonstrations, will be available to assist site
» * . « . _sr _!».. *« « A **•£•/* l«oc«c
uj tautuM"'"*'*""*"*^" o — — *••
managers in implementing presumptive remedies on a site-specific basis.
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Table 1
Current Presumptive Remedies and Contacts
Site Type/Schedule
General Policy and Procedures
(9/93)
Volatile Organic Compounds
(VOCs) m Soils
(9/93)
Wood Treaters
(094)
Municipal Landfills
(9/93)
Contaminated Ground Water
(1.94)
'Region 7 Pilots -
PCS Sites. Coal Gas Sites.
Grain Storage Sites (6/94)
KEY:
TBO - To Be D«termin*d
NA • Not Applicable
Presumptive Remedy(ies)
NA
Soil Vapor Extraction. Thermal
Desorption. Incneration
For Organics -
Incineration, Bioremediation.
Oechlorination
For Inorganics -
Immobilization
Containment (could include
capping, leachate collection
and treatment. IF gas
treatment, institutional
controls, etc.)
Pump and Treat
(Will specify preferred
treatment technologies &
describe overall approach)
TBD
Anticipated Products ....
Presumptive Remedies:.
Policy and Procedures
Presumptive Remedies: Site
Characterization and
Technology Selection for
CERCLA Sites with VOCs in
SoHs -
Presumptive Remedy: Wood
Treating Sites
Technology Selection Guide lor
Wood Treater Sites (S/yS)
Presumptive Remedy lor
CERCLA Municipal Landfill Sites
TBD
TBD
„ EPA Contact
Shahid Mahmud
Headquarters. HSCO
(703)603-8789
Shahid Mahmud
Headquarters. HSCO
(703)603-8789
Lisa Boynton
Headquarters. EHD
(703) 603-9052
Harry Allen
Emergency Response Division
(908)321-6747
Andrea Mclaughlin
Headquarters. HSCO
(703) 603-8793
Ken Lovelace
Headquarters. hSCO
(703) 603-8787
Diana Engeman
Region 7
(913)551-7746
Q5.
A.
Model (SACM). SACM incorporates the
experience gained from past Superfund actions
into an integrated approach to site cleanup aimed
at getting response action decisions made and
implemented more quickly. The presumptive
remedies initiative is one mechanism for
accomplishing the broad streamlining goal set
forth by SACM. The presumptive remedies
initiative was also identified as one of the
Administrative Improvements to Superfund in
June of 1993.
What Other Presumptive Remedy
Initiatives Are Underway or Planned?
There are a variety of presumptive remedy activities
currently planned or underway. Table 1 lists the
site types with the anticipated schedule of associated
presumptive remedy products that are currently
underway along with the Headquarters and Regional
contacts. There are four site types for which
presumptive remedies are being developed in EPA
Headquarters: VOCs. wood treaters, municipal
landfills, and contaminated ground-water sites.
Concurrently, Region 1 is preparing presumptive
remedy guidances for PCB. coal gasification, and
grain storage sites.
Q6. How Will Presumptive Remedies Affect
the Remedy Selection Process?
A. Presumptive remedies are anticipated to affect
several phases of the current remedy selection
process. A diagram depicting the generic impacts
on the overall process is provided in Table 2.
Data collection during the initial site assessment
(Preliminary Assessment/Site Inspection (PA7SI)
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Table 2
Generic Effect of Presumptive Remedies
Phases of Cleanup Process
OIILHOJI-OOMLUI
3
5
i
PA/SI or Removal Site Evaluation
Scoping
• Collect and analyze existing data
• Identity initial projocfOUs and remedial
action objectives
• Identify range of likely alternatives
• Identify potential ARARs
• Identify initial DQOs
• Prepare project plans
Remedial Investigation
* Conduct field investigation
• Define nature and extent of contamination
• Identify ARARs
• Conduct baseline risk assessment
Remedy Selection
• Identify potential treatment technologies
and containment/disposal requirements
• Screen technologies
• Assemble technologies into altemagves
• Screen alternatives as necessary to reduce
number subject to detailed analysis
• Further refine alternatives as necessary
• Analyze alternatives against the nine
criteria and each_other
Proposed Plan
Record of Decision
Remedial Design
Effect on
Cleanup Process
X
o
@
©
0
o
©
x<1>
O"'
O
O<"
•
•
•
•
©
0
'<&'
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0,
) = Not impacted @ = Streamlined
* Focused W = Eliminated
Streamlined for Municipal Landfills
or Removal Site Evaluation) can be used to help
define the specific site type and to determine whether
presumptive remedies may be potentially
applicable.
Assuming the site warrants further attention (i.e., it
is listed on the National Priorities List (NPL) or
determined by the Regional. Decision Team (RDT)
to be an NPL-caliber site or to merit a removal
action), further confirmation of the site type should
take place as either an RI/FS or EE/CA is scoped to
determine whether the site is a potential candidate
for presumptive remedies. For a detailed discussion
of how to make this determination, refer to the
appropriate site type-specific directive. If it is
determined that the site falls into a certain category,
the presumptive remedies associated with that site
type should be included in the list of likely remedial
alternatives (e.g., no action, presumptive remedies,
etc.) for the site. Other aspects of scoping that may
be affected by presumptive remedies are the
designation of appropriate operable units (OUs)
and identification of data needed to support the
evaluation and selection of a presumptive remedy.
Presumptive remedies are expected to help focus
data collection efforts. Specifically, initial data
collection would focus on confirming the site type.
If the site is of the type for which presumptive
remedies have been developed, the streamlined
steps for site characterization outlined in the site
type-specific directive for the particular site type
should be followed. These steps outline data
collection to determine the extent of contamination
and to support selection of the presumptive remedy
and Remedial Design (RD).
Presumptive remedies will streamline the FS and
the alternatives analysis in the EE/CA more than
any other phase of the remedy selection process. In
most cases, after a site is confirmed as being a type
for which presumptive remedies exist, a focused
FS or EE/CA which eliminates the technology
identification and screening step would be prepared.
The study would limit its consideration to the no
action alternative and the presumptive remedy
technologies. This is possible because EPA has
conducted an analysis of potentially available
technologies for most of the presumptive remedies
site categories and has determined that certain
technologies are routinely and appropriately
screened out either on the basis of effectiveness,
implementability, or excessive cost (NCP Section
300.430 (e)(3) and (7)), or have not been selected
under the nine criteria analysis identified in NCP
Section 300.430 (e) (9). This detailed analysis will
serve to substitute forthe development and screening
of alternatives phases of the FS (and will allow the
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Q7.
A.
Q8.
remaining alternatives to be limited to variations of
the presumptive remedy). The site-specific directive
and supporting documentation (e.g., "Feasibility
Study Analysis for CERCLA Municipal Landfill
Sites") along with this directive then can be placed
in the administrative record for the site 1:6 support
the elimination of the screening step identified in
section 300.430 (e) (1) of the NCP. Further
supporting materials can be provided by
Headquarters (e.g., FS reports included in the
analysis, technical reports), as needed. The specific
presumptive remedy directives address the process
of eliminating the alternatives development and
screening step of the RI/FS or EE/CA in further
detail. The directives also provide generic
discussion of a partial nine criteria analysis
(excluding state ARARs and community and state
acceptance) and may help streamline the detailed
analysis of alternatives within the FS and EE/CA
reports. However, the user is cautioned that the
criteria are discussed on a general basis and the nine
criteria analysis should be supplemented to reflect
the site-specific conditions.
The Proposed Plan (PP) and subsequent ROD
would be similarly streamlined by focusing only on
the presumptive remedy(ies). The remedial design
(RD) may be streamlined since some RD data will
likely have been collected previously during the
site assessment and RI.
How Will Presumptive Remedies Affect
the Removal Process?
Non-time critical removal actions are anticipated
to be used more often to accomplish early actions
at Superfund sites under SACM. The presumptive
remedies approach will focus the data collection
during the removal site evaluation and reduce the
number of technologies identified and analyzed in
the EE/CA. Presumptive remedies are not expected
to have an impact on emergency and time-critical
actions under the removal program.
What are the Implications of
Presumptive Remedies for Innovative
Technologies?
The NCP in section 300.430 (a) (1) (iii) (E) states
that "EPA expects to consider using innovative
technology when such technology offers the
potential for comparable or superior treatment
performance and implementability, fewer or lesser
adverse impacts than other available approaches.
or lower costs for similar levels of performance
than demonstrated technologies." The use of die
presumptive remedies may tend to reduce the
frequency of the full evaluation of innovative
technologies. However, as indicated previously,
the presumptive remedies provide a tool for
streamlining the remedy selection process.They
do not preclude the consideration of innovative
technologies should the technologies be
demonstrated to be as effective or superior to the
presumptive remedies. Innovative technologies
may be evaluated and recommended in addition to
the presumptive remedies where these criteria are
met.
EPA encourages review of the latest Innovative
Technologies Semi-Annual Reports or Engineering
Bulletins for the up-to-date information on the
potential effectiveness and applicability of various
innovative technologies. Site managers are strongly
encouraged to involve the site-type expert team
(see Question 13) to determine whether unusual
circumstances exist to consider a non-presumptive
remedy based on site-specific conditions and/or
community, state, and PRP concerns, or the
availability of a potentially promising innovative
technology.
Q9. How Will Presumptive Remedies Affect
Risk Assessments?
*» j
A. Generally, the role of baseline risk assessments
under the presumptive remedy approach would be
unaffected with Municipal Landfill sites being a
notable exception. It is anticipated that risk
assessments would still be needed on a site-specific
basis to assist site managers in determining the
need for a response action. EPA managers have
indicated the value of the risk assessment in
communicating with states. PRPs, and local
communities about the nature and extent of health
and environmental threats. Therefore, it is
recommended that the current risk assessment
process be continued on an individual site basts
except for Municipal Landfills. The site manager
should refer to the EPA Directive entitled
"Presumptive Remedy for CERCLA Municipal
Landfill Sites." Directive No. 9355.0-49FS to
identify streamlining opportunities at Municipal
Landfill sites.
Guidance on developing risk-based preliminary
remediation goals (PRGs) would be unaffected
under this initiative. These goals are needed for
individual sites especially in the absence of ARARs
to assist in determining which remedial options
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Q10.
A.
will result in medium-specific chemical
concentrations that are protective of human health.
For example, there may be several candidate
presumptive remedies identified in the site-type
directives. But it is the extent and degree of
contamination across a given site that will determine
whether a technology, which is predicted to reduce
a chemical's concentration to some specified level,
will be adequate by itself to produce protective
concentrations following remedial action. For
some sites or site locations, because of the magnitude
of contamination or co-occurrence of contaminants.
it may be necessary to assemble several technologies
into a treatment train to adequately reduce levels of
all chemicals of concern in a medium to protective
levels. In other cases, it may be necessary to
evaluate the use of institutional and/or engineering
controls on an area following remediauon to ensure
protection during subsequent land use. In other
words, it is not reasonable to assume that because
a specific technology resulted in "protection" at
one site, it will result in protective levels at all sites.
A determination that the selected remedy will result
in protection of human health and the environment
must be made for each site. Both ARARs and risk-
based PRGs are important tools in this exercise.
Generally, presumptive remedy directives will
specify those technologies that have been
determined to achieve levels protective of human
health and the environment under a variety of site
conditions. However, because all sites differ to
some extent, especially in their relation to
surrounding communities and sensitive ecosystems.
adetermination must still be made on a site-specific
basis as to how a given remedy design is expected
to achieve "protectiveness" during remedy
construction and following remedial action. Overall
protection of human health and the environment is
one of two threshold considerations (the other
being compliance with ARARs) that must be met in
order for an alternative to be eligible for selection
as the-remedy for a given site.
What if Outside Parties such as PRPs
or the Community Want Other
Alternatives Considered?
The identification of a presumptive remedy does
not relieve EPA of the obligation to propose the
remedy for public comment, or to respond to
0.11'.
comments suggesting that other alternatives should
have been considered. In some cases, the
information in the site-type directive and supporting
documentation may be sufficient to address such
comments: in others, additional analysis may be
required to assess the relative merits of an alternative
technology proposed by a commenter.
To reduce the risk of delay due to the need to
respond to such comments, it is generally desirable
to publicize the planned use of presumptive remedies
early on. and give States, communities, PRPs. and
others an early opportunity to express any concerns
they may have about focusing the FS or EE/CA in
this way. The agency may then decide whether to
include additional alternatives in the FS or EE/CA
so that those concerns can be addressed before the
remedy is proposed.
In general, it is expected that the directive and
supporting documents will provide substantial
justification for preferring the presumptive remedy
over alternative technologies. Therefore, the
submission of comments advocating other
approaches does not necessarily require broadening
of the FS or EE/CA, or conducting additional
analysis after the plan has been proposed. Whether
additional documentation is required will depend
upon how substantial or persuasive the comments
are (e.g.. whether a comment identifies unusual site
circumstances that seriously call into question the
applicability of the presumptive remedy). The
Region will have to assess this by evaluating each
comment on its own merits.
It should be noted that even if the FS is broadened
to consider alternatives other than the presumptive
remedy, much of the benefit of the presumptive
remedy approach can still be achieved. In such
cases, it is not necessary to address the full array of
possible technologies, rather only the presumptive
remedy and the specific altemati ve(s) that genuinely
warrant detailed study. Therefore, the FS can still
be narrowed and data gathering can still be focused.
How do State ARARs Affect the Use of
Presumptive Remedies?
Any remedy, including presumptive remedies, must
be selected in accordance with Section 121(d)
(2)(A)(ii) of the Comprehensive Environmental
Response, Compensation and Liability Act
-------
(CERCLAJ. which specifies that selected remedial
actions comply with promulgated standards under
Federal and more stringent State environmental
laws (i.e.. State ARARs). At this time it is difficult
to predict situations where presumptive remedies
will not comply with State ARARs, and such issues
must necessarily be addressed on a site-specific
basis. However, as the presumptive remedies have
been widely selected, they are likely to be capable
of meeting State ARARs.
Q12. What Are the Implications of
Presumptive Remedies on Community,
PRP, and State Relations?
A.
It will generally be desirable to notify the
community. State, and PRP(S) as early in the clean-
up process as possible that presumptive remedies
are being considered for the site. This notification
can take the form of a fact sheet, a notice in the
newspaper, and/or a public meeting in which the
site manager( with assistance from the expert team,
as desired) explains the rationale for taking such
actions and distributes the appropriate directives of
the site type in question. Additionally, the site
manager should explain the potential benefits
associated with the use of presumptive remedies
such as time and cost savings, and consistency.
Early discussions about the rationale for
presumptive remedies should help instill confidence
in both the technologies and remedy selection
processes.
Q13. How Will EPA Communicate Progress
on Current Presumptive Remedies,
Newly Developed Presumptive
Remedies, and Future Issues Related
to Presumptive Remedies?
A. Information about presumptive remedies will be
communicated in several ways. First, it is
anticipated that an orientation will be provided to
communicate the key elements of presumptive
remedies to Regional site managers as appropriate.
This may be followed by periodic meetings with
expert teams, if necessary, to scope out the
applications of presumptive remedies on a site-
specific basis. The expert team may also be used to
convey any new developments on technology or
policies and procedures for general or specific
applications. A quarterly conference call is also
anticipated between site managers and the expert
teams to allow for the exchange of ideas and to
identify and resolve technical issues. Technology
selection directives. SACM Bulletins, and Q&A
directives will be published periodically to
disseminate information on presumptive remedies
and related issues as they arise. Finally, the
presumptive remedies directives on the various site
categories will be updated every several years to
reflect new technology development and up-to-
date performance data, as appropriate.
Notice:
i i
The policies set out in this document are intended solely as guidance to the U.S. Environmental
Protection Agency (EPA) personnel; they are not final EPA actions and do not constitute rulemaking
These policies 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
document, or to act at variance with the guidance, based on an analysis of specific site circumstances
EPA also reserves the right to change the guidance at any time without public notice.
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SERA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Publication9203.1 -021
August f992
Super-fund Accelerated
Cleanup Bulletin
Presumptive Remedies
Superfund Revitalization Activity
Office of Emergency and Remedial Response
Hazardous Site Control Division OS-220W
Intermittent Bulletin
Volume 1 Number 3
Since Superfund's inception in 1980, the removal and remedial programs have found that certain site categories have
similar characteristics, such as types of contaminants present, past industrial use, or environmental media affected.
Based on a wealth of information acquired from evaluating and cleaning up these sites, Superfund is undertaking an
initiative to develop presumptive remedies that are appropriate for specific site types and/or contaminants. This
initiative is part of a larger program, known as the Superfund Accelerated Cleanup Model (SACM), which is designed
to speed all aspects of the Superfund clean-up process.
The objective of the presumptive remedies initiative is to use clean-up techniques shown to be effective in the past at
similar sites in the future. The use of presumptive remedies will streamline removal actions, site studies, ar.d clean-up
actions, thereby improving consistency, reducing costs/and increasing the speed with which hazardous waste sites are
remediated.
This bulletin outlines the Superfund efforts underway for developing presumptive remedies for various types of sites.
Presumptive Remedy Selection Initiatives
Superfund has selected four site type catego-
ries to test the presumptive remedy se-
lection approach. Each category was o
selected based on the number of j|\^
potential sites, the amount of his- ^
torical information available, the
type of contaminants, and the
technologies selected in the past
for remediating these types of
sites.
Several approaches are being
evaluated for determining the
most effective method(s) for
implementing the presumptive remedy selection pro-
cess. The approaches consist of Regional training on the
implementation of a streamlining guidance document
for landfill sites, developing new guidance or policy to
streamline remedy selection at other categories of sites,
and establishing expert teams to help evaluate sites and
make decisions on appropriate clean-up methods.
Municipal Landfill, Wood Treater, Solvent, and Con-
taminated Ground Water Sites will be the first types of
sites where the presumptive remedy approach is tried at
a national level. Additional pilot efforts are being tried
at the Regional level on PCB, Coal Gasification, and
Grain Storage sites. It is anticipated that the number of
site types that lend themselves to the presumptive rem-
edy selection process will be expanded as more infor-
Faster... C/eaner...Safer
mation becomes available and more experience is gained
on the approach.
The following is a brief description of the
efforts to be carried out under each
site-type category.
\
Municipal Landfill Sites
The goal of this initiative is to
assist the Regions in imple-
menting the recently developed
guidance on Conducting Reme-
dial Investigations/Feasibility
Studies for CERCLA Municipal
Landfill Sites. The focus of the
guidance is to streamline site characterization, baseline
risk assessment, and selection of remedial alternatives
for Municipal Landfill (MLF) sites.
A team of experienced Remedial Project Managers
(RPMs) and experts on landfill construction have worked
with RPMs for municipal landfill sites in Regions 1,4,
and 5. The team provided assistance in scoping a stream-
lined Remedial Investigation and Feasibility Study (RI/
FS). These RPMs will become a resource for their Re-
gions, and will assist other RPMs in streamlining their
MLF sites.
Two additional pilots are planned for this summer. The
purpose of these pilots is to bring the remaining Regions
into the pilot project, so that every Region will have at
£8) Printed on Recycled Paper
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least one individual who is knowledgeable about the
streamlining methods identified in the manual. It is in-
tended that RPMs who participate in the pilot projects will
become membersofan "Expert Team" forMunicipal Land-
fills and will be available to assist other RPMs in designing
streamlined processes for their sites. (Contact: Andrea
McLaughlin 703-603-8793)
Wood Treatment Sites
The goal of this initiative is to speed up response actions at
wood treatment sites. This acceleration will be accom-
plished by narrowing the list of potential technologies
from which to choose a remedy, early in the remedy
selection process. Program experience, guidance and an
expert team will be used in concert to identify technologies
that may be applied to specific situations. This approach
will provide the flexibility required to accommodate site-
specific characteristics, while shortening the time required
to identify, select, and implement a remedy.
This initiative includes establishment of an expert team;
development of a presumptive remedy selection process,
using a selection outline and matrix; development of a
series of fact sheets; and performance of pilot studies and
ad hoc site support to implement the presumptive remedy
initiative at wood treatment sites. The expert team consists
of representatives from the Environmental Response Team
(ERT), the Office of Research and Development (ORD),
On-SceneCoordinators(OSCs)and Remedial Project Man-
agers (RPMs) with extensive experience at wood treatment
sites. The presumptive remedy selection process will fol-
low a generic outline of site activities and rely upon a
technology selection matrix to determine appropriate rem-
edies according to technical criteria. The fact sheets will be
used to report on the progress of this initiative and to
distribute information on the presumptive remedy pro-
cess. Pilot studies and ad hoc site support will be used to
implement the initiative in the field as it is refined by the
expert team. (Contact: David Ouderkirk 202-260-5614)
Solvent Sites
The goal of this initiative is to expedite response actions at
sites contaminated with solvents by focusing on a limited
number of effective technologies early in the remedial
process. This initiative will develop guidance on standard-
izing remedy selection and will issue a series of fact sheets
on technology selection and site characterization strate-
gies, and clean-up criteria for solvent-contaminated soils
and sediments.
As with the other site types, this initiative will include the
establishment of an expert team of representatives from
ERT, ORD, and experienced OSCs and RPMs to he-1
evaluate sites and streamline the remedy selection proct
The initiative will involve conducting pilot studies to test
implementation of the presumptive remedy approaches at
sites contaminated with solvents. Finally, the initiative will
develop a technical and policy directive on streamlining
the RI/FS process at these types of sites. (Contact: Shahid
Mahmud 703-630-8789)
Ground Water Sites
This initiative will consist of developing a Quick Reference
Fact Sheet that discusses the selection of a presumptive
remedy for sites with contaminated ground water. This is
especially relevant in light of the fact that over 75 percent
of sites currently listed on the National Priorities List
(NPL) exhibit ground-water contamination. The develop-
ment of presumptive remedies for ground-water contami-
nation sites will include the Agency's most recent policies
pertaining to sites that contain non-aqueous phase liquids
(NAPLs), both dense phase (DNAPLs) and light phase
(LNAPLs). In addition, EPA. will evaluate publishing a
notice in the Federal Register that will contain a generic
evaluation of six of the nine evaluation criteria set forth for
the selection of remedial alternatives in the National Con-
tingency Plan (NCP) (excluding ARARs, and community
and state acceptance). The Federal Register Notice would
allow for public review and comment on the application of
the six generic analysis criteria for ground-water conta '
nated sites. (Contact: Ken Lovelace 703-630-8787).
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. D.C. 20460
OFMCEOF
SOLID WASTE AND EMERGENCY RESPONSE
MEMORANDUM
SUBJECT: Presumptive Remedies Directives
FROM: Richard J, Guirnond ~
Assistant Surgeon General, USPHS
Acting Assistant Administrator
TO: Director, Waste Management Division
Regions I, IV, V, VII
..,.-'• ' .Director, Emergency and Remedial Response Division
.Region II
Director, Hazardous Waste Management Division
Regions III, VI, VIII, IX .
Director, Hazardous Waste Division
Region X
5 Director, Environmental Services Division
Regions I, VI, VII
PURPOSE
The purpose of this memorandum is to transmit for Regional
use the three directives entitled "Presumptive Remedies: Policy
and Procedures," "Presumptive Remedies: Site Characterization and
Technology Selection for CERCLA sites with Volatile Organic
Compounds in Soils," and "Presumptive Remedy for CERCLA Municipal
Landfill Sites." These directives are a part of a continuing
series of directives :being developed under the recent Superfund
Administrative Improvements initiative to accelerate site
cleanups. . . ,
This memorandum also transmits a list of Presumptive
Remedies Regional Contacts available to assist Regional staff in
implementing these directives.
BACKGROUND
In January of 1992, a workgroup was formed in response
to the Superfund 30-Day Study to develop "presumptive remedies"
for specific types of sites and contaminants. Presumptive remedy
guidance was to be based on historical patterns of remedy .
selection and EPA1 s scientific and engineering evaluation of
performance data on technology implementation for common
categories of sites. It was determined that the use of
presumptive remedies would improve the efficiency of the
Superfund process by building on past program experience and that
this guidance would provide practical tools to the Regions for
Printed on OicyclodR
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accomplishing the bread streamlining and acceleration goal set
forth by the Superfund , Accelerated Cleanup Moael (SACK).
Through this effort, seven site categories have
identified for presumptive remedy guidance development. iwo or
these site types are addressed in the attached directives.
Additional directives addressing woodtreater, polychlorinated
biphenyls (PCBs) , coal gasification, grain storage, and
groundwater sites will.be issued in FY 94.
OBJECTIVE
Use of the attached and subsequent directives by the
Regional Decision Teams, Site Assessment Managers (SAMS), on-
Scene Coordinators (OSCs), and Remedial Project Managers (RPMs)
should streamline the Superfund site evaluation and cleanup
process, thereby improving consistency/ reducing costs, ana
increasing the speed at which sites are cleaned up. Generally,
these benefits will be realized by eliminating the need for
initial identification and screening of alternatives during the
Feasibility Study (FS)' or Engineering Evaluation/Cost Analysis
(EE/CA) , streamlining the detailed analysis step of tne FS, and
focusing data collection during site investigations which in turn
may streamline remedial design. Additionally, it is anticipated
that both the RI and the baseline risk assessment may be
streamlined for municipal landfill sites.
Specifically, the "Policy and Procedures" directive
discusses a number of common issues encountered in using
presumptive remedies directives (e.g., impact of presumptive
remedy directives on risk assessment; selection of innovative
technologies). By doing so, this directive provides a broad
policy and procedural framework for the full series of category-
specific directives.
The "Volatile Organic Compounds (VOCs) in Soils" directive
identifies Soil Vapor Extraction (SVE), Thermal Desorption, and
Incineration as the presumptive remedies for Superfund sites with
VOC contaminated wastes. Through use of a decision tree, this
directive provides a streamlined process for site
characterization and remedy selection at these types of sites.
Additionally, the directive identifies both policy and practical
considerations for implementing this directive.
The "Municipal Landfill" directive establishes containment
as the presumptive remedy for CERCIA municipal landfills. The
directive also highlights and emphasizes the issportance of
certain streamlining principles related to th® scoping (planning)
stage of the RI/FS, provides guidance concerning the level of
detail that is appropriate when assessing risk associated wxth
the municipal landfill source area, and discusses factors to
consider when making the site-specific decision concerning
whether characterization and treatment of hot spots is warranted.
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"Demonstration" projects implementing these presumptive
remedies approaches are currently underway at four municipal
landfill sites and at one VOCs-in-soils site. Other
demonstration sites are being sought in the above-mentioned
categories to assist headquarters in evaluating the costs and
benefits of implementing these directives, as well as practical
lessons learned.
IMPLEMENTATION
These directives and their respective presumptive remedies
are expected to be used at all appropriate sites. The approaches
described in each directive are designed to accommodate a wide
range of site-specific circumstances. In some cases, multiple
technologies are included (e.g., VOCs); in others,various
components of the presumptive remedy are optional, depending on
site situation (e.g., municipal landfills). Further, these
directives recognize that at some sites, there may be unusual
circumstances (such as complex contaminant mixtures, soil
conditions, or extraordinary State and community concerns) that
may require the site manager to look beyond the presumptive
remedies for additional (perhaps more innovative) technologies or
remedial approaches.
Regional staff are encouraged to contact their Regional
Presumptive Remedies Contacts with questions related to
these directives (See Attachment 1). Further, quarterly
conference calls will be arranged by headquarters to establish a
forum for discussion of additional concerns or program
experiences. The results of demonstration projects (as
available) will also be discussed during these conference calls.
Finally, site-type expert teams will be available to provide
detailed site-specific technical assistance to Regional staff on
an as-needed basis.
These directives along with detailed supporting
documentation (e.g., "Feasibility Study Analysis for CERCLA sites
with Volatile Organic compounds in Soils," "Feasibility Study
Analysis for CERCLA Municipal Landfill Sites") should be placed
in the Administrative record to justify the presumptive remedy
approach for a particular site. The above-mentioned
documentation will be forwarded to the Regional Presumptive
Remedies contacts this fall. Additional documentation (e.g.,
feasibility study reports included in the analysis, other
technical reports) supporting this initiative will be available
through Superfund headquarters.
Attachments
cc: Superfund Removal Managers, Regions I-X
Superfund Branch Chiefs, Regions I-X
Superfund Section Chiefs, Regions I-X
Regional Counsel Branch Chiefs, Regions I-X
OSWER Division Directors
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• "'".*!* :.'•- — ;~l-V'f'. .•
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&TTACHI4E1CT I
PRESUMPTIVE REMEDIES REdlOMAL CQHT&CTS
PHOME MUMBER
HIKE NALXPXMSKS
212-264-7681
MEL HAUPTMAN
215-597-3163
PAUL LEONMIP
404-347-7791
FELICIA BARMOT
312-886-4742
214-655-6720
§13-551-7728
303-294-7146
VICTOR KETTELAPPER
415-744-2370
CRAIG COOPER
206-553-2106
KEVIH ROCHLIM
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United States
Environmental Protection
Agency
Office of Directive: 9355.0-48FS
Solid Waste and EPA 540-F-93-048
Emergency Response PB 93-963346
September 1993
cvEPA
Presumptive
Site Characterization and Technology
Selection For CERCLA Sites With
Volatile Organic Compounds In
Office of Emergency and Remedial Response
Hazardous Site Control Division 5203G
Quick Reference Fact Sheet
Since Superfund's inception in 1980, the remedial and removal programs have found that certain categories of sites have
^^^^
^^
5^
guidance on presumptive remedies for wood treatment, municipal landfill PCB grain storage coal
gasificafonandcontaminatedground-watersites. EPAh«dsodeveIo|^.d^wSd^S!
SSSSfeT^T- * C 9i55-/°-47FS) which ou"ines -d Besses the issues common t7al pr
remedies (e.g.. role of mwvanve technologies, consistency with the NCR. State, community involvement)
PURPOSE
The purpose of this directive is to provide guidance on
selecting a presumptive remedy at sites with soils
contaminated with VOCs. Specifically this guidance:
• Presents the presumptive remedies for this site
type;
• Describes the presumptive remedy process in terms
of site characterization and technology screenin"
steps; and , „..,„. °
Outlines the data required to select these
presumptive remedies.
Since a presumptive remedy is a technology that EPA
believes, based upon its past experience, generally will
be the most appropriate remedy for a specified type of
site, the presumptive remedy approach will accelerate
site-specific analysis of remedies by focusing the
feasibility study efforts. Where several presumptive
remedies are identified. EPA believes that all deserve
substantial consideration before utilizing the
presumptive remedy approach. EPA personnel should
review the directive entitled Presumptive Remedies:
Policy and Procedures (Directive 9355.0-47FS) for
general information on the presumptive remedy process.
Soil vapor extraction (SVE), thermal desorption,
and incineration are the presumptive remedies for
Superfund sites with VOC-contaminated soil assuming
the site characteristics meet certain criteria. Table T
provides a brief description of each of these presumptive
remedies.
The decision to establish these technologies as
presumptive remedies for this site type is based on
EPA's collective knowledge about site investigation
and remedy selection for VOC-contaminated soils,
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TABLE 1
Presumptive Remedies for VOCs
in Soil
Soil Vapor Extraction - Soil vapor extraction
(SVE) is an in-situ or ex-situ process which
physically removes contaminants from vadose
zone soils by inducing air flow through the soil
matrix. The flowing air strips volatile compounds
from the solids and carries them to extraction
wells. The recovered vapors may require further
treatment. In-situ SVE is the primary focus of this
document.
Thermal Desorption -Thermal desorption is an
ex- situ process that uses direct or indirect heat
exchange to vaporize organic contaminants from
soil, sediment, sludge or other solid and semisolid
matrices. The vapors are then condensed or
otherwise collected for further treatment.
Incineration - Incineration is an ex-situ
engineered process that employs thermal
decomposition via oxidation at temperatures
usually greater than 900 °C to destroy the organic
fraction of the waste.
The major difference between thermal desorption
and incineration is that incineration oxidizes
organic compounds, thereby destroying the
hazardous material. Thermal desorption
volatilizes contaminants, then concentrates them.
Thermal desorption reduces the volume of
contamination, but the concentrated waste stream
still requires treatment. Disposal or treatment of
residual waste stream, ash, and concentrated
VOC effluent is not covered by this directive.
Options such as off-site disposal/regeneration or
reuse should be considered.
including field experience from the Superfund, Resource
Conservation and Recovery Act (RCRA). and
Underground Storage Tank (UST) programs. In addition,
EPA conducted an analysis of FY86 to FY91 Records of
Decision (RODs) for sites where VOC contamination
drove remedy selection. The results of this analysts,
which are provided in Appendix A, demonstrate that these
three technologies represent over 90% of the remedies
selected in the RODs analyzed.
USE OF DOCUMENT
This directive is primarily intended for use by Superfund
site managers. However, site managers in other programs
(such as RCRA corrective action, the UST program,
States), and the private sector, may also use this directive.
This directive is not a "stand alone" document. To ensure
a full understanding of VOC site characterization and
remedy selection, site managers should refer to all
documents cited in the directive. For assistance in
understanding complex site conditions, an experienced
site manager, the presumptive remedy expert team, the
Superfund Technical Assistance and Response Team
(START) team, or the Environmental Response Team
should be consulted.
ANTICIPATED BENEFITS OF
PRESUMPTIVE REMEDIES
Use of this directive will reduce cost and time in remedy
selection at VOC sites in the following ways:
1. The directive facilitates identification of the presumed
or likely remedial options early in the investigation
process, hence allowing foramore focused collection
of data during the remedial investigation (RI) or
removal 4te evaluation. In addition, knowledge of
the presumptive remedy may facilitate collection of
some remedial design data before the ROD or action
memo, thereby allowing the action to proceed more
quickly after signature of the decision document.
2. This directive eliminates the need for the initial step
of identifying and screening a variety of alternatives
during the Feasibility Study. Additionally, it will
reduce the number of technologies identified and
analyzed in the EE/CA. The National Oil and
Hazardous Substances Pollution Contingency Plan
(NCP) (Section 300.430(e)(l)) states that "the lead
agency shall include an alternatives screening step,
when needed, (emphasis added) to select a reasonable
number of alternatives for detailed analysis." EPA's
analysis of feasibility studies for VOC-contaminated
soil sites (see Appendix A) found that certain
technologies are routinely screened out based on
effectiveness, implementability, or excessive costs,
consistent with NCP Section 300.430(e)(7).
Accordingly, EPA has determined that, when using
presumptive remedies at VOC-contaminated sites,
site-specific identification and screening of
alternatives is not necessary. However, this directive
and supporting documentation (see "Feasibility Study
Analysis for CERCLA Sites with Volatile Organic
Compounds in Soils") should be included in the
Administrative Record for all sites that use the
presumptive remedy(ies) to document the basis for
eliminating the "site-specific identification and
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TABLE 2
Typical VOCs Addressed by this
Directive
Halogenated Volatile Organics
Carbon Tetrachloride
Chlorobenzene
Chlo'roethane
Chloroform
1,1-Dichloroethane
1,1 -Dichloroethylene
1,2-Dichlorobenzene
1,2-Dichloroethane
1,2-Dichloroethylene
1,2-Dichloropropane
1,4-Dichlorobenzene
1,1,1 -Trichloroethane
1.1,2-Trichloroethane
1,1,2,2-Tetrachloroethane
Ethylene Dibromide
Methylene Chloride
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Non-Haloaenated Volatile Oroanics
Ketones/Furans
Acetone
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Aromatics
Benzene
Ethyl Benzene
Styrene
Toluene
m-Xylene
o-Xylene
p-Xylene
Note: Other compounds that have physical/chemical
characteristics similar to the compounds listed may
also be addressed by the presumptive remedy
process.
3.
screening of technologies" section. In addition, other
supporting materials (e.g., FS reports included in the
analysis, technical reports) will be made available at
EPA Headquarters and are available for inclusion in
the Administrative Record if needed.
Thisdirecti ve streamlines the detailed analysis portion
of the FS. Remedial alternatives developed for a site
must be evaluated against the nine criteria (required
under NCP Section 300.430(e)(9)). Under this
presumptive remedy approach, the detailed analysis
can be limited to the three presumptive remedies (in
addition to the no-action alternative), thereby
streamlining that portion of the FS. Appendix B
provides a generic evaluation of the presumptive
remedies for seven of the nine criteria. Thisevaluation
may serve as a basis for each detailed analysis
conducted under the presumptive remedy process
and should be augmented, as needed, to address site-
specific conditions.
One of these presumptive remedies is expected to be used
for all VOC sites except under unusual circumstances.
Such circumstances may include unusual site soil
characteristics, demonstration of significant advantages
of alternate (or other innovative) technologies over the
presumptive remedies, or extraordinary community and
state concerns. If such circumstances are encountered,
additional analyses may be necessary or a more
conventional detailed RI/FS may be performed.
PRESUMPTIVE REMEDIES PROCESS
This section and the accompanying diagram (Figure 1)
describe the sequence of steps involved in the presumptive
remedy process (site characterization and technology
selection) for sites containing soil contaminated with
VOCs. While the process is not mandatory, EPA believes
that following the steps outlined below will expedite the
clean-up process for this category of sites.
SVE is the primary presumptive remedy. SVE has been
selected most frequently to address VOC contamination at
Superfund sites and initial performance data indicate that
it effectively treats waste in place at a relatively low cost.
In cases where SVE will not work or where there is very
highly concentrated contamination, thermal desorption
may be the more appropriate response technology. In a
limited number of situations, incineration may be more
appropriate.
The numbered paragraphs below correspond to the
numbered steps in Figure 1 and provide a detailed
discussion of each step.
1. Are VOCs Present in the Soil'.' The first step is to
determine whether VOCs are the major contaminant
present in soil at the site. Table 2 lists the VOCs that
are amenable to the presumptive remedies outlined in
this directive. If VOCs are present at levels of
concern (see forthcoming guidance on soil screening
levels), then the presumptive remedies outlined in
this directive may be applicable. However, if it is
confirmed (at this point or at any later point during the
presumptive remedy process) that there are no VOCs
present in the soil, then this directive is not applicable
for use in technology selection at the site.
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FIGURE 1
Decision Tree for Investigating and Selecting a Remedy at Solvent Sites
Inmate
•arty
PRP.
Stale.
and
community
involvement
il
presumptive
remedy
approach
is
appropriate.
Assemble
Administra-
tive Record
ArenonVOC
contaminants
that preclude the
pmsumptrvB
ody'
This (act sheet is not
applicable.
N
Review advantages/
limitations table lor
presumptive remedies
Conduct tune-critical
removal action, if
necessary
Identify
ARARs
and Pre-
lim nary
Remedia
ton
Goals
(PRGs)
Site
Character
ization
Have any new
contaminants been
detected that
preclude the
presumptive
remedy?
Proceed with
ROD or Action
Memo and
implementation.
Complete assessment to
determne whether there is
an unacceptable nsk to
humans or the
environment and refine
PRGs
Is SVEsM feasible
alter conducting
pSot study?
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Most likely, this analysis will occur during scoping
oftheRI/FSorEE/CA. However, there may be only
limited information available at that time about the
site. Therefore, whatever information is available
should be used to determine whether VOCs are present
or suspected in the soil based on prior use. Chemical
use at a site can be ascertained from a number of
sources such as facility records, previous sampling
efforts by local or State agencies or through
Information Request letters.
2. Are Non-VOC Contaminants Present That Preclude
the Use of Presumptive Remedies? In addition to
determining whether VOCs are present in the soil, it
is also necessary to identify other non-VOC
contaminants, if any. present in the soil.
The site characterization and technology selection
procedures outlined in this directive are recommended
for use primarily on soil containing VOCs only. See
Table 2 for VOCs that are amenable to the presumptive
remedies.
For sites containing a mixture of VOCs and other
contaminants in soil, the presumptive remedies should
be considered only if they can also be effective in
removing the non-VOC contaminants or combined
with other, non-presumptive remedies in a treatment
train, assuming the presumptive remedies do not
exacerbate the problems presented by the non-VOCs.
For example, sites with VOCs and metals commingled
in soil may be effectively remediated by employing
SVE to remove VOCs followed by fixation or
solidification to address the metal contamination. In
contrast, a VOC and polyaromatic hydrocarbons
(PAHs) contaminant combination may be treated
more appropriately w.ith a single biological treatment
scheme that would be effective for both the VOCs and
PAHs. Note that sites containing mixtures of VOCs
and non-VOCs are varied, and. for this reason, remedy
selection may be more complicated than the
framework presented in this directive; therefore, the
, presumptive remedy analysis may need to be
supplemented or modified on a site-specific basis.
3. Initiate Early Community, State, and Potentially
Responsible Party (PRP) Involvement. As early in
the clean-up process as possible, EPA should notify
the community. State, and any PRPs that a presumptive
remedy is being considered for the site. It is important
for all stakeholders to understand completely how the
presumptive remedy process varies from the usual
clean-up process and the benefits of using the
presumptive remedies process.
Early identification of State applicable or relevant
and appropriate requirements (ARARs) also is a
critical part of this process. Because the presumption
set forth in this directive is national in scope, it does
not take into account State ARARs. For this reason,
State ARARs relating to the presumptive remedies
should be considered on a site-specific basis. Regions
may want to supplement this directive by compiling
the requirements of the States in their Regions that are
likely to be associated with the use of the presumptive
remedies and placing them in the administrative
record for a site where presumptive remedies are
being considered. This directive along with the
"Feasibility Study Analysis for CERCLA Sites with
Volatile Organic Compounds in Soils" should be
included in the administrative record for the site if one
of the presumptive remedies is proposed for a particular
VOC-contaminated site.
4. Review Advantages/Limitations of the Presumptive
Remedies. During initial site characterization. Table
3 should be reviewed to consider the advantages and
limitations of the presumptive remedies. This
information may be useful in preparing for and/or
modifying the site characterization or alternatives
analysis process. The "Practical Considerations"
section of this directive should also be reviewed at
this time to ensure a comprehensive site
characterization and remedy evaluation.
5. Conduct Site Characterization. Site characterization
for sites using VOC presumptive remedies should be
designed to:
• Positively identify the site type (i.e., VOC site);
• Obtaindatatodeterminewhetherthepresumptive
remedy is feasible for the site;
• Focus (and possibly streamline) site
characterization by collecting data to support the
selection of presumptive remedy(ies) only (e.g.,
volume and cost information); and,
• Collect some design data (i.e., pilot studies to
determine radius of influence and flow rates of
SVE), thereby streamlining datacollection during
the remedial design stage.
Table 4 lists the data that are required for
characterization of sites with soil contaminated with
VOCs. This table also includes the rationale for
collecting these data and references for established
collection methods. Note that bench-scale and pilot/
treatability studies should be performed whenever
possible concurrent with site characterization todefine
the parameters that will be important to designing the
system.
In areas with low organic content soil (e.g., alluvial
basins), or where there are impediments to obtaining
soil samples (e.g., under buildings), soil gas sampling
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is highly recommended as a site characterization
technique. In addition, the use of soil gas sampling
during implementation of S VE and confirmatory soil
sampling afterward is less expensive than constantly
installing new soil borings, especially for deep
contamination. '
If incineration or thermal desorption is under serious
consideration, bench-scale treatability studies may
be conducted, especially if metals or other inorganic
compounds are present. Thermal desorption generally
should be considered if concentrations of VOCs are
less than 5 to 10 percent; incineration may be
appropriate if VOC concentrations exceed 5 to 10
percent. Note that excavation and mixing of soil can
produce a desorber input of less than 10 percent
contaminant concentration and allow thermal
desorption to be chosen.
Additionally, the feasibility of excavation should be
determined by evaluating surface conditions and depth
of contaminants as well as the potential for any air
emissions associated with the excavation. Test digs
should be monitored closely to assure protection of
the public and the environment.
It \st important to note that during the site
characterization, the volume and concentration of
waste constituting the principal threats at the site
should be identified. The NCP (Section
300.430(a)(l)(iii)(A)andAGuiVferoPrmcJ/Ki;r/jr
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10. Does the Pilot/Treatability Study Indicate that SVE
isFeasible? SVE is the primary presumptive remedy.
Pilot/treatability study testing of SVE should be
conducted prior to final remedy selection. Such
testing will provide information on the rate of removal
of contaminants. EPA/540/2-91/091A cited in the
References section of this directive providesguidance
on conducting the pilot/treatability study. Removal
efficiencies and treatment effectiveness must be
carefully considered alongside the PRGs identified in
the FS toestimate the potential for successful remedial
action using SVE.
11. Is Thermal Desorption Feasible? If SVE will not be
sufficiently effective in achieving PRGs due to low
permeability, lithology or insufficient removal of
contamination during the pilot study, thermal
desorption should be considered as the primary ex-
situ presumptive remedy.
Thermal desorption technologies cover a variety of
vendors and processes. However, ample data are
available to substantiate remedy selection of thermal
desorption for soil contaminated solely with VOCs.
12. Is Incineration Feasible'.' If contaminant
concentrations and bench-scale testing indicate
thermal desorption will not achieve desired PRO
levels, incineration is the second ex-situ presumptive
remedy.
If incineration is planned, and a substantial numberof
inorganic contaminants are expected to be present
based on site characterization data, materials handling
problems, or slagging problems are likely.
If noneof the three presumptive remedies is considered
to be .feasible at a particular site, it will be necessary
to consider other technologies. (For more information.
refer to the Practical Considerations section below.)
13. Select Remedy for Remedial/Removal Action. At this
point, there should be enough data to identify a
preferred remedy in the proposed plan and distribute
the plan for public comment. Once the remedy has
been selected in the ROD, the user can proceed to do
a limited design which relies largely on the substantial
amount of design-related data collected during the
RI. The extent of additional or supplemental data
required will be determined on a site-specific basis.
Practical Considerations
The following factors should be considered prior to taking
any remedial action.
Enforcement: This directive applies to fund-lead sites as
well as to sites where a PRP is conducting the investigation
and/or response action. In the event that there is an
ongoing PRP-lead RI/FS, the scope of work may be
amended to reflect the presumptive remedy approach to
site characterization and remedy selection. The potential
savings in time and money to be gained by using the
presumptive remedy approach are expected to outweigh
the burden of modifying the scope of work in many cases.
Initial Site Actions: If the VOC material is still in
original, intact containers, it may be returned to the
manufacturer (if the manufacturer is willing to accept
these containers), assuming this response is a cost-effective
and feasible action as opposed to treating the material.
Reuse of material (i.e., process liquids and relocation of
equipment to other permitted facilities) should also be
considered. Further, phase separation should be conducted
and recycling considered depending on the purity of the
recovered phase or for any existing liquids that are high
enough in concentration. Refer to Appendix C for a list of
the currently recognized waste exchanges.
Site Characterization: Site characterization should
proceed as a single, multi-media activity whenever
possible. Field screening methods should be integrated
into the sampling and analysis plan in order to accelerate
information gathering. Data quality must reflect the
ultimate use of the information.
Ground Water: The decision maker should consider the
ground-water strategy for the site since soil clean-up
levels are-often set to protect ground-water quality.
Therefore, ground-waterclean-up levels may have a direct
impact on the selected clean-up levels for soil. (See
forthcoming guidance on Soil Screening Levels and the
directive entitled Presumptive Remedies: Remedial
Strategy and Treatment Technologies for CERCLA Sites
with Contaminated Ground Water.) It should be noted
that, of the VOC-type contaminants, listed in Table 2, the
halogenated volatiles are dense nonaqueous phase liquids
(dense NAPLs or DNAPLs) and many of the others are
light NAPLs (LNAPLs) in their pure liquid form. If
LN APLs are present, it may be possible to address them by
lowering the water table, removing free product (if present),
and applying SVE. To address DNAPLs contamination,
refer to the above mentioned ground-water guidance.
Management of Different Soils: A situation may arise
where highly contaminated shallow material cannot be
addressed by SVE. The action to address this contamination
may differ from the rest of the soil contamination and will
most likely involve incineration or thermal desorption. If
it is suspected that soil contamination existing at greater
depths will also be treated in this manner, then the excavated
shallow material should be staged and stored in order to
treat it with the deep material.
Another situation may arise where VOCs are mixed with
metals, and none of the presumptive remedies can address,
both sets of contaminants. The action to address this
situation may consist of a treatment train where VOCs are
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addressed through SVE or thermal desorption and the
metals are addressed through fixation.
Finally, the site manager should be aware of situations
where a mixture of principal and low-level threat wastes
call for the use of treatment (i.e., SVE or thermal treatment)
of principal threat waste and containment (capping) of
low-level contamination. (See A Guide to Principal
Threat and Low-Level Wastes in Reference Section).
Off-SiteDisposal: In general, it may not be cost-effective
to ship quantities of contaminated soil in excess of 5,000
cubic yards for off-site disposal. For this reason.
pretreatment of soil and water may be required prior to
shipment or discharge to another treatment facility.
Capping: Capping alone is not recommended to control
the migration of VOCs. However, capping can improve
the effectiveness of SVE by Decreasing the rate of
infiltration of residual VOCs through the vadose zone into
the ground water as well as possibly increasing the radius
of influence and preventing "short circuiting" of air
pathways in the vicinity of the extraction well. Capping
can also be used to address non-principal threat waste
unless it is more cost-effective to treat this waste along
with more highly contaminated materials.
Patents: SVEisapatenled technology. Royalty payments
may be required under certain conditions of
implementation.
Attainment of Remediation Goals: It should be noted
that, like other in-situ technologies, it is difficult to
ascertain with confidence whether SVE will attain
remediationgoals until the action is actually implemented.
However, the lower cost and ease of SVE implementation
will often weigh heavily in its favor, as long as protection
of human health and the environment is ensured.
Additional Technologies: If for some reason none of the
presumptive remedies is applicable to a particular site, the
si te manager is encouraged to refer to EPA's forthcoming
document entitled Contaminants and Remedial Options
at Solvent Sites for a discussion of additional VOC treatment
technologies. It should be noted that this comprehensive
document, which identifies additional VOCs and
technologies, may be appropriate to consider on a site-
specific basis.
Thermal Treatment Technologies: The site manager
should refer to EPA's Draft Strategy for Combustion of
Hazardous Waste (May 18, 1993) when considering any
thermal treatment technologies at a particular site.
Conclusion
For sites containing VOC-contaminated soil and
appropriate soil characteristics, SVE is a relatively
inexpensive and efficient technology. If material needs to
be excavated, thermal desorption is preferred. In a few
cases, incineration may be the most appropriate remedy -
- for example, where SVE and thermal desorption will not
meet clean-up criteria based on contaminant concentrations
or composition. •-
As remedies other than SVE, thermal desorption and
incineration become more widely used in the future, this
directive may be modified to reflect these trends. For
furtherassistance on presumptive remedy related activities
consult the Regional Presumptive Remedies contact.
Notice:
f
The policies set out in this document are intended solely as guidance to the U.S. Environmental
Protection Agency (EPA) personnel; they are not final EPA actions and do not constitute rulemaking.
These policies 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
document, or to act at variance with the guidance, based on an analysis of specific site circumstances.
EPA also reserves the right to change this guidance at any time without public notice.
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TA. £3
Comparison of Technologies for VOC Sites
PERFORMANCE
.(D
ADVANTAGES
LIMITATIONS
COSTS
d)
S
"B
UJ
5
Q.
3
Can be as high as 99%
removal of VOC
contaminants but is
typically tower than other
technologies with range
0(85-99%
i High level of effectiveness in removing
VOCs.
• Relatively inexpensive.
< Little site disturbance; no excavation
required.
. Effective for waste under buildings or
other construction.
Soil that is tight or has high moisture content (>50%) has a reduced permeability to air,
hindering the operation of SVE.
Soil with a high degree of heterogeneity has highly variable permeabilities, resulting in uneven
delivery of gas flow to the contaminated regions, which in turn reduces removal rates by SVE.
Soil with high organic content or that is extremely dry has a high sorpttori capacity for VOCs,
which results in reduced removal rates.
SVE may require treating residual soil tailings, liquids, and spent activated carbon.
Air emissions must be controlled to eliminate possible harm to the public and the environment.
SVE is not effective in the saturated zone. However, lowering the aquifer can expose more
media to SVE (this may address concerns regarding LNAPLs).
$10 - 150Aon
95-99% removal of VOCs
All compounds that are listed on Table 2
are readily treated by thermal desorption.
> Because of tower treatment temperatures
and often lower oxygen levels, thermal
desorbers should produce less nitrogen
oxides and sulfur dioxide than
incinerators.
> Process can be performed onsite or
offsite.
i Lower temperatures produce fewer
products of incomplete combustion
(PICs).
Requires excavation. If contamination is very deep or below the water table, excavation
may be difficult and expensive.
Mercury, if present, can be removed from soil by thermal desorption and impose additional
treatment costs for ttie oflgas.
Soil containing high fractions of clay or silt may result in a high percentage of paniculate carry-
over from the desorber into downstream treatment devices.
Soil that contains constituents greater than 1 to 2 inches in diameter will require screening or
crushing to prevent jamming the mechanical equipment.
Soil with a high moisture content (>30%) can result in tow processing rates, high operating
costs, and difficulty in materials handling.
High or tow pH wastes may corrode the metal components of the system, requiring
pretreatment.
Potential process residuals are treated solids, oversized debris, condensed contaminants and
water, paniculate control system solids, and contaminated activated carbon.
Air pollution control system required.
$2QO-300/!on
>99% removal of VOCs
o
••5
> Capable of accepting a wide range of
media.
' Processes can be performed onsite or
offsite.
' Metals can be concentrated in the
residuals.
• Requires excavation. If contamination is very deep or below the water table, excavation may be
difficult and expensive.
« Soil containing high fractions of clay or sift may result in a high percentage of paniculate carry-
over from the incinerator into downstream treatment devices.
• Air pollution control equipment is required.
• High treatment temperatures, as compared to thermal desorption, can produce nitrogen oxides,
sulfur dioxides, and PICs.
• Solids with volatile metals may require additional treatment or more elaborate air pollution
equipment.
$200-
1700/ton
NOTES:
(1) Actual performance and cost for any remediation technology is highly site specific. Both depend upon the original and target clean-up level concentrations of contaminants,
soil quantity to be treaed, soil characteristics, and the design and operation of the remediation technology equipment used.
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TABLE 4
Information Required for Characterization and Technology Selection at VOC Sites
INFORMATION
RATIONALE FOR COLLECTING ^FORMATION
REFERENCE
All Technologies:
Site Geology
SVEis most effective in porous, permeable, homogeneous sol. Highly heterogeneous soil (i.e., fractured porous
rock or sands interspersed with clay lenses) may exhibit a'r flow channelng through highly permeable soils. Abo.
desorpticn kinetics may be slow h some siuaticns (i.e., high organic content or high clay content sol). In these
cases, mass transfer kheticsmay reduce the rate of removal of SVE bebw that which is expected by calculations
wlh a local equilibrium model a pilot scale experiments carried out for only a few days. Often diffusion kinetbs
Imitations can be substantialy reduced by proper design of the SVE facility.
Guidance for Conducting Remedial
Investigations and Feasiblity
Studes under CERCLA {pp. 3-3 to
3-20) EPA/540/G-89/004
USGSSoilClassificatbn
For SVE to be effective, the sol must have sufficient pneumatic permeablity (>10 cm ) to perml air to move
through themedum. Sand/, gravely soils are the most conductive to SVE, while clays and silts are tess conductive.
However, remedaticns using SVE in clays and silts have been successful. Soil permeablity may need to be
measured in the field.
ASTMD2487
ASTMD2488
Soil Moisture
H'gh moisture content h soil may drastically decrease its air permeability and, thus, the effectiveness of SVE The
site rrust be sufficiently well drahedtoprevent the severe reduction in air permeability, which occurs whenthe
percent water saturatbn of the soil is greater than 50%. Conversely, organics can be strongly adsorbed onto
extremely dry soils, which also rnpedes SVE. The moisture content of the sol will affect the amount of energy
required to heat the sol, the target temperature and the handling properties of line-grahedsdl. Thermal desoiption
requires that the moisture content of the soil be less than 39%.
ASTMD2216
ASTMD3017
Depth to Ground Water
SVEis not effective in saturated soil. However, the waiertablecan be loweredby pumping. Theimal desoiption
and hcineratbn are more expensive for high moisture soilr '
Guidance for Conducting Remedial
Investigations and Feasiblity
Studes under CERCLA (pp.3-3to
3-20) EPA540/G-89AB4
Contamhant Identity
and Properties
Boiing Poht -Thermal desoiption target temperature is dependent on contaminant boilng point.
Vbpor Pressure • SVE is effective for compounds with a vapor pressure greater than 0.5 mm Hg at sol
temperatures.
D'mensionless Henry's Constant • SVE is effective tor compounds with a dmensionless Henry's constant higher
than 0.01 at soil temperatures.
Water Solubility • SVE is more successful for compounds with tower solubilties.
Liquid and vkpor Density -A contaminant witha density greater than water may form a DN&PL A contamhant win
adensity less than water may form an LNAPL. The flow characteristics of a compound's vapor fa SVE is a function
of its vapor density.
CFC Chembal Handbook
-------
TABL
Information Required for Characterization and Technology Selection at VOC Sites
(Continued)
INFORMATION
RATIONALE FOR COLLECTING INFORMATION
REFERENCE
AH Technologies: (continued)
Contaminart Concentration,
Location, Volume, and Depth
Presence of Pipes or Subsurface
Material
These data can be gathered via soil matrix ancVor soil gas sampling. Soil gas sampling, both shallow and at depths,
may be more appropriate, given depth to ground water and stratigraphy.
Thepresenceof vater or electrical conduits, sol fracture lines, debre, or any other objects that are more permeable
than the surrounding soil will be the preferred pathway for the advecting gases.
SVEOnly:
Soil/Air Filled Porosity
Soil/Air Permeability
Soil Temperature
Soil Humic Content
Contaminart Soil Soiption
Coefficiert Kd (Since Kd is less
readily avalable, Kcc, the
equlibnum between
contaminants soibed orto
organic car ton versus the
ground water is used.)
Contaminart Adsorption
Characteristics on Activated
Carbon
Porosity should be less than 40% for SVE to be effective.
Soil/air permeabilty should be greater than tO^crr? for air to move throughout the cortaminated soil. SVEis
potentially effective in less permeable soil (i e. , between 1 0 -6to 10-1 0 cm2 ), but further pibl-scale testhg and/or
mathematical modelng is recommended to better predct the t me for cleanup (vMch is likely to be prolonged for
lower permeability soil).
Contamhart vapor pressure, dhienaortess Henry's Law cons tart, water solubiity, and phase density are strong
functions of temperature. •'
Solvents adhere strongly to soil with high humc content, which decreases the effectiveness of SVE.
The parameter describes the tendency of the solvent to sorbortoscil or organic matter in the soil. Higher Kcc's
indicatethata subsurface is more Ikely lobird tocarbon rich mecfa (i.e., soil) than toremain in water.
The parameter is related to the feasiblity of removing contamiiarts from residuals by carbon adsoiptioa This
parameter is important since compounds such as MEK become unstable as they are adsorbed onto caibon.
Gu dance for Conducting Remedial
Irvestigatbnsand Feasiblity
Studies Under CERCLA (pp. 3-3 to
3-20) EPA/540/G-89/004
Geotechnical Techniques
Guidance for Conducting Remedial
Irvestigatbnsand Feasiblity
Studies Under CERCLA (pp. 3-3 to
3-20) EPA/54(yG-89/004
Gudance for Conducting Remedial
Irvestigatbnsand FeasibSity
Studies Under CERCLA (pp. 3-3 to
3-20) EPA/540/G-89/004
Guidance for Conducting Remedial
Irvestigatbnsand Feasiblity
Studies Under CERCLA (pp. 3-3 to
3-20) EPA/540/G-89/004
Guidance for Conducting Remedial
Irvestigatbnsand FeasibSity
Studes Under CERCLA (pp. 3-3 to
3-20) EPA/540/G-8W004
RREL Trealability Database
RREL Treatability Database
-------
TABLE 4
Information Required for Characterization and Technology Selection at VOC Sites
(Continued)
INFORMATION
RATIONALE FOR COLLECTING INFORMATION
Incineration and Thermal Desorption Only:
Soil Plasticity
Soil BTU Content
Contaminant Combustion
Characteristics
Soil Particle Size Distribution
Alkaline Metal Satis
(e;g..NaS04,KS04)
Volatile Metals Content
(e.g.. Hg, Pb. Cd, Zn. Sn)
Plastic soil, when subjected to compressive forces, can become molded into large particles that are difficult to
heat.
The soil BTU content determines the fuel requirements for thermal desorption and incineration.
Information on combustion characteristics of a VOC is required in order to determine the combustion
characteristics of the incinerator.
Thermal desorption usually requires that soil be pretreated to a maximum soil particle size ranging from 1 to 2
inches. —
Alkaline metal salts may cause refractory attack and slagging at high temperatures
High metal content may cause ash leaching and stack emission^ problems.
REFERENCE
Guidance for Conducting Remedial
Investigations and Feasibility
Studies under CERCLA (pp. 3-3 to
3-20) EPA/540/G-89/004
ASTMD3286
Bench/Pilot Testing
ASTMD422
Percentage of Na. K
Heavy Metals Analysis
N)
BTU = British Thermal Units
LNAPL = Light Nonaqueous Phase Liquid
DNAPL = Dense Nonaqueous Phase Liquid
mm Hg = millimeters of mercury pressure
NAPL = Nonaqueous Phase Liquid
PIC = Products of Incomplete Combustion
-------
APPEND9X A
TECHNICAL BASIS FOR PRESUMPTIVE REMEDIES
This Appendix summarizes the analyses that EPA conducted of Record of Decision (ROD) and
Feasibility Study (FS) data from VOC-contaminated sites which led to establishing soil vapor extraction
(SVE), thermal desorption. and incineration as the presumptive remedies for Superfund sites with VOC-
contaminated soil. The analyses consisted of:
• Identifying VOC-contaminated sites
• Determining the frequency of technology selection for VOC sites
• Identifying sites for the feasibility study (FS) analysis
• Conducting the FS analysis.
Results of these analyses, along with the scientific and engineering analysis of the performance data
on technology application (Primary Reference document), provide a support for the decision to eliminate
the initial alternatives identification and screening step for this site type. These technical reviews found
that certain technologies are appropriately screened out based on effectiveness, implementability, or
excessive costs. Review of technologies against the nine criteria led to elimination of additional
alternatives. Provided below is a discussion of each analysis.
Identification of VOC-Contaminated Sites
The first analysis involved generating a list of signed Records of Decision (RODs) (post-SARA).
documenting VOC contamination, from which data could be used for subsequent analyses. The ROD
Information Directory database was used for this purpose. Of the 821 signed FY86-FY91 RODs. 418
are identified in the database as containing VOC contamination in source material. This list of RODs
was subsequently divided into two lists: RODs where VOCs were the only contaminants of concern
identified in the source material and RODs containing VOCs, as well as other contamination, in source
material. For those RODs involving VOC plus other contaminants, a review of the ROD document was
conducted to identify cases where only VOCs were driving the selection of remedy. To make this
determination, the Remedial Response Objectives and Selected Remedy sections of the ROD were
reviewed to identify specific language indicating that the remedialaction was designed to address only
the VOCs at the site. In addition, if cleanup goals were specified only for VOCs. the assumption was
made that VOCs were driving the remedy.
As a result of this analysis. 88 RODs were identified as VOC-only RODs or VOCs plus other
contaminants RODs where a clear determination could be made that VOCs were driving the selection
of remedy.
Frequency of Technology Selection for VOC-Contaminated Sites
Table 1 presents the distribution of the 88 FY86-FY91 RODs among the treatment technologies used
to address VOCs in soil. This table demonstrates that the three presumptive remedies (SVE. thermal
desorption. and incineration) together were selected more often (over 90% of the RODs analyzed) than
the other applicable technologies. Presumptive Remedies were also those remedies where a fair
amount of performance data on technology implementation was available. Furthermore, SVE. chosen
in over two-thirds of the RODs analyzed, was the primary presumptive remedy selected.
Identification of Sites for Feasibility Study Analysis
The purpose of the FS analysis was to document the technology screening step in FSs of VOC-
contaminated soil/sludge sites and identify the principal reasons given for eliminating technologies from
further consideration. To achieve a representative sample of FSs for the analysis, sites were selected
using ROD data according to the following criteria:
13
-------
APPENDIX A
TECHNICAL BASIS FOR PRESUMPTIVE REMEDIES
(Continued)
Table 1
Presumptive Remedy VOC Site Treatment
Summary Table, FY86-FY9V
TECHNOLOGIES USED TO
ADDRESS VOCs IN SOIL
Bioremediation <"
Incineration
Soil Flushing/Washing (1>
Soil Vapor Extraction
Thermal Treatment m
Total
TOTAL
3
11
3
62
9
88
Source: ROD Information Directory (RID), FY86 - FY91
Notes: (1 ) Relatively limited amount of performance data available for these technologies
versus the presumptive remedies.
(2) Thermal treatment includes RODs employing thermal desorption, thermal aeration,
low-temperature thermal desorption, and the generic remedy "thermal treatment".
* A population of 418 RODs was identified for this study based on the parameters: FY 1986-1991,
and VOC contamination of source media.
Sites were chosen, based on the selected remedy, to ensure an even distribution among the five
treatment technologies for VOCs in soil (i.e., bioremediation, incineration, SVE, soil flushing, and
thermal treatment).
Whenever possible, both VOC-only sites and VOC and other contamination sites were represented
under each technology.
Sites were selected to ensure an even distribution in geographic location, ROD signature date,
and site size.
Feasibility Study Analysis
The FS analysis involves a review of the technology screening phase, including any pre-screening steps,
followed by a review of the detailed analysis and comparative analysis phases in each FS and ROD.
Information derived from each review was documented on site-specific data collection forms, which are
available for evaluation as part of the Administrative Record for this directive. (See "Feasibility Study
Analysis forCERCLA Sites with Volatile Organic Compounds in Soils", September 1993, available at EPA
Headquarters and Regional Offices.)
14
-------
APPENDIX A
TECHNICAL BASIS FOR PRESUMPTIVE REMEDIES
(Continued)
For the screening phase, the full range of technologies considered was listed on the data collection forms,
along with the key reasons given for eliminating technologies from further consideration. These reasons
were categorized according to the screening criteria: cost, effectiveness, or implementability. The
frequency with which specific reasons were given for eliminating a technology from further consideration
was then tallied and compiled into a screening phase summary table (Table 2).
For the detailed analysis and comparative analysis, information on the relative performance of each
technology/alternative with respect to the nine NCP criteria was documented on the site-specific data
collection forms. The advantages and disadvantages associated with each clean-up option were
highlighted. In some cases, a VOC technology was combined with one or more technologies that address
minor site contaminants into one or more alternatives. Only the component of the alternative which
addressed the VOC contamination was evaluated in this analysis. The disadvantages of a technology/
alternative were then compiled into a detailed analysis/comparative analysis summary table, under the
assumption that these disadvantages contributed to non-selection. All summary tables are available for
review as part of the Administrative Record.
The FS analysis has been completed for 21 sites (representing approximately 25% of universe studied).
The information from these FSs has been compiled and summarized in Table 2. Additional FS analysis
is planned and will be added to the Administrative Record, when available. Table 2 demonstrates that
technologies, other than the presumptive remedies, are consistently eliminated from further consideration
in the screening phase due to effectiveness, implementability, or excessive costs. In addition, the
analysis indicates that, although certain technologies routinely passed the screening phase, these
technologies were selected infrequently because they did not provide the best overall performance with
respect to the nine criteria. Together these analyses (Appendix A to this directive and "Feasibility Study
Analysis for CERCLA Sites with Volatile Organic Compounds in Soils"), along with the scientific analysis
of performance data (USEPA (In Progress) Contaminants and Remedial Options at Solvent Sites) will
support the decision of using presumptive remedies and bypassing the technology identification and
screening step for a particular site. As previously indicated, this factsheet and accompanying analysis
should be part of the Administrative Record for the site. Further supporting materials, not found in the
Regional files, can be provided by Headquarters, as needed.
15
-------
TABLE 2 • SUMMARY OF SCREENING AND DETAILED ANALYSIS FOR VOC SITES1
Capping
21
Oflsite
Nonhazardous
Oflsite RCRA
Disposal
.18
12
10
Onsite
Encapsulation
Onsite
Nonhazardous
O\
Onsite RCRA
Landfill
14
11
Activated
Sludge
Composting
Land
Farming
Bioremediation
(unspecified)
Ex-situ
Bioremediation
In-situ
Bioremediation
11
10
Dechtorination/
APEG
-------
TABLE 2 « SUMMARY OF SCREENING AND DETAILED ANALYSIS FOR VOC SITES (Continued)1
REMEDIAL
TECHNOLOGY
OR
TREATMENT2
Other Chemical
Destruction
Reduction
Neutralization
Oxidation
Offsite
Incineration
(unspecified)
Onsite
Incineration
(unspecified)
Fluidized
Bed
Infrared
Pyrolysis
Multiple
Hearth
Rotary
Kiln
Other
Incineration
Other Thermal
Treatment
3
7
6
6
16
7
5
5
3
5
11
13
6
^
n
0
0
0
1
7.
1
0
i
0
0
6
1
0
^
3
6
6
5
8
6
4
4
3
4
3
12
6
^
/%?
0
i
0
0
1
0
1
0
0
1
2
0
0
^
y& *tk s
f$S(
0
0
0
0
5
2
3
2
2
2
3
5
2
/ / IFSsWrww
&$s Criterion Conlrtbuted. A
&"/ To ScrMnJrw Out3 s\/
0
0
0
0
0
0
0
.1
0
0
2
1
0
ifPcfF/'
0
0
q
i
7
i
0
0
0
0
4
0
0
/ / /
/ / IflODs Where Criterion Contributed to Non-Selection
•^•$"1 r
f^
0
0
0
0
2
0
0
0
0
0
1
0
0
..Ov>
OJ*
0
0
0
0
0
0
0
0
0
0
0
0
0
t^
0
0
0
0
1
0
0
0
0
0
0
0
0
^f-
0
0
0
0
0
0
0
0
0
0
0
0
0
#
0
0
0
1
7
1
0
0
0
0
5
0
0
CP*
0
0
0
1
6
1
0
0
0
0
3
0
0
s
0
0
0
1
2
0
0
0
0
0
4
0
0
^
•-
-•
--
-•
--
•-
-•
••
•-. - .
•-
•-
-•
--
^
••
-
••
••
-
••
••
-
••
-
-------
TABLE 2 • SUMMARY OF SCREENING AND DETAILED ANALYSIS FOR VOC SITES (Continued)1
REMEDIAL
TECHNOLOGY
OR
TREATMENT2
I RODs Where Criterion Contributed to Non-Selection
Vitrification
12
Wei Air
Oxidation
Low Temperature
Thermal Desorp/
Stripping
13
10
1..
In-situ Sleam
Stripping
Soil
Flushing
15
12
oo
Soil
Washing
14
12
10
0
In-silu Vacuum
Extraction
17
11
10
B.E.S.T.
Process
Liquified
Gas
Other Physical
Extraction
Fixation
Stabilization/
Solidification
13
Aeration
12
10
-------
« RODs Where Criterion Contributed to Non-Selection
REMEDIAL
TECHNOLOGY
On
TREATMENT 2
TABLE 2 » SUMMARY OF SCREENING AND DETAILED ANALYSIS FOR VOC SITES (Continued)1
In-situ
Hydrolysis
Soil
Slurries
1 This study was conducted on 21 RODs and their corresponding FSs.
2 This does not the include the no-action or institutional control only alternatives. No RODs selected either ot these as remedies. .,...,,
3 -f* SnfelS^^ onecnterton tor screening or non-selectwn ol technology. Abo. some FSs did no. lully explam the criteria lorscreenmg out a technology. Thus, the totals lor
screening and non-selection criteria are not equal to the number ol FSs and RODs considered.
4 information on State and community concerns was not included m this analysis because FSs do not conta.n this mlormat.on and RODs generally only
reference supporting documentation (i.e., State concurrence tetter and responsiveness summary).
-------
SOIL VAPOR EXTRACTION
§.
till1 SsfgS £lg§=-5? f
' * ?§
a
3-HLOI3
51
Il
3 0:55
I
a -o
s 3
-
5 s o w
g §• §.
-------
APPENDIX B
Criteria Evaluation for Technologies Used to Treat VOC-Confaminated Soil
(continued)
o
o,
oz
o
(0
HI
D
^
^
oc
H
CRITERIA
Overall Protection of
Human Health and the
Environment
• Provides both short-
and tang-term
protection by
eliminating exposure to
VOCs in soVsludge.
• Prevents further
goundwater
contamination and
of (site migration.
•
Requires measures to
protect workers and
community during
excavation, handling,
and treatment.
Compliance With
Federal ARARs
• Requires compliance with
RCRA removal .treatment,
transponation(ifoffs$e
treafrnent), and land
dsposal regulations (if a
hazardous waste).
• Excavation, construction,
and operation of onsito
treatment unit may require
compliance with wetlands
and other location -specie
ARARs.
• Treats hazardous waste to
BOAT levels; thus, there is
no LDR problem with
residuals.
• Generally, treats wastes to
levels ti at wiB prevent
exceedanceol ground-
wal erdearmp levels.
• Emission controls are
needed to ensure
compliance with air quality
standards.
Long-Term
Effectiveness and
Permanence
« Effectively removes
contamination source.
• b a well-demonstrated
technique for removing
VOCs from soii/siudge.
• involves some treatment
or disposal of residuals
generally through use of
carbon adsorpforV
regeneration or disposal.
Reduction of Toxitity,
Mobility, or Volume
Through Treatment
* Significantly reduces
toxidty, mobility, or
volume of contaminants
through treatment.
' Generally requires test
runs to ensure effective
treatment.
»• • •
Short-Term
Effectiveness
• Presents potential short-
term risks to workers and
community from air release
during excavation and
treatment (if onsle
t re a3 men!).
• Involves potential short-term
risks from hand ling and
transporting waste (i offeite
treatment).
• Relatively short timeframe
to achieve ctean-up levels.
Implemen {ability
* Construction and
substantive permit
requirements of an onsite
treatment unit may present
somedtleulties. Mobile
incineration units for ensile
treatment are available.
• Limited offsite treatment
capacity exists.
* Used successfully at other
Supedund sites to address
sotvent contamination.
' Requires engineering
measures to control air
emissions, fugitive dust,
run-off, erosion and
sedrnentation, site access,
and transportation
Cost"1
$200- 3007
ton
$250Aon
avg.
1. Mote: AdualcostofareniedationtecrTiologyishighrysite-speciia I is dependent upon theoriginaland target clean-up level cw(^ralions ()(oortaminants, soil characteristics, and the design
and operakon of the remediation technology used
-------
APPENDIX B
Criteria Evaluation for Technologies Used to Treat VOC-Contamlnated Sol!
(continued)
z
o
i
cc
UJ
0
CRITERIA
Overall Protection of
Human Health and the
Environment
• Provides both short- and
tang-term proteclion by
eliminating exposure to
solvent contaminants in
soil.
• Prevents further ground-
water contamination and
oflsite migration.
• Requires measures to
protect workers and
community during
excavation, handling, and
treatment.
Compliance With
Federal ARARs
• Requires compliance witi
RCRA removal, treatment,
transportation (if offsrte
treatment), and land
disposal regulations (if a
hazardous waste).
• Excavation, construction,
and operation of onsite
incinerators may require
compliance witi wetlands
and otier location-specific
ARARs.
• Treats hazardous waste to
BOAT levels; tius, tiere is
no LOR problem wit)
residuals.
• Treats wastes to levels that
wffl prevent exceedance of
ground-water clean-up
levels.
• Emission controls may be
needed to ensure
compliance wft air quality
standards during eceavation
and con suction.
Long-Term
Effectiveness and
Permanence
• Effectively destroys source
of contamination.
• Is a well-demonstrated
technique fortreafng VOCs
in soiYsludge.
• No organic residuals
contamination wil exist if
treating soil/sludge
contaminated only with
VOCs.
B*
Reduction of Toa'cfty,
Mobility, or Volume
Through Treatment
• Significant reduces
toxicily. mobility, or
volume of contaminants
through treatment.
Short-Term
Effectiveness
. Presents potential short-
term risks to workers and
community from air
release during
excavation and
treatment (if ensile
treatment).
• Involves potential short-
term risks from handing
and transporting waste
(I of site treatment).
. Relatively short
timsframe to achieve
clean-up levels.
Implementability
. Construction and
substantive permit
requirement of an
onsite incinerator may
be some what difficult.
Mobile incinerators
are readily available.
• Limited oflsite
incineration capacity
exists.
• Used successfully at
otier Superfund sites
to address VOC
contamination.
Co,,"1
S200-1700/
ton
$400ytonavg.
1. Note: Actual cost of a remediation technology is highly site-specific and dependent upon the orignal and target clean-up teve! concentrations of contaminanls. sol characteristics, and the design and
operation of the remedation technology used
-------
APPENDIX C
U.S. Waste Exchanges
CALIFORNIA WASTE EXCHANGE
Robert McCormick
Department of Health Services
Toxic Substances Control Division
400 P Street
Sacramento, CA 95812
(916)324-1807
INDIANA WASTE EXCHANGE
Environmental Quality Control
1220 Waterway Boulevard
P.O. Box 1220
Indianapolis, IN 46206
(317)232-8188
INDUSTRIAL MATERIAL EXCHANGE
SERVICE
Diane Shockey
2200 Churchill Road, #31
Springfield, IL 62794-9276
(217)782-0450
FAX: (217)782-9142
INDUSTRIAL MATERIALS EXCHANGE
Bill Lawrence
172 20th Avenue
Seattle. WA 98122
(206) 296-4899
FAX: (206)296-0188
PACIFIC MATERIALS EXCHANGE
Bob Smee
1522 North Washington Street. Suite 202
Spokane. WA 99205
(905) 325-0551
FAX: (509)325-2086
NATIONAL WASTE EXCHANGE NETWORK
1-800-858-6625
RENEW
Hope Castillo
Texas Water Commission
P.O. Box13087
Austin. TX 78711
(512)463-7773,
FAX: (512)463-8317 ; , :;i/^%::: :
INDUSTRIAL WASTE INFORMATION
EXCHANGE
William E. Payne
New Jersey Chamber of Commerce
5 Commerce Street
Newark, NJ 07102
(201) 623-7070
MONTANA INDUSTRIAL WASTE EXCHANGE
Don Ingles
Montana Chamber of Commerce
P.O. Box 1730
Helena. MT 59624
(406) 442-2405
NORTHEAST INDUSTRIAL WASTE EXCHANGE
Lewis M. Culter
90 Presidential Plaza. Suite 122
Syracuse. NY 13202
(315)422-6572
FAX: (316)422-9051
SOUTHEAST WASTE EXCHANGE
MaxiMay
Urban Institute
Department of Civil Engineering
University of North Carolina
Charlotte. NC 28223
(704) 547-2307
SOUTHERN WASTE INFORMATION
EXCHANGE
Gene Jones
P.O. Box 960
Tallahassee, FL 32313
(904)644-5516
FAX: (904)574-6704
23
-------
APPENDIX D
GLOSSARY
ApplicableorRelevantand Appropriate Requirements
£AEARsl - CERCLA Section 121 (d) and the NCP require
thatonsite remedial actions must attain (orjustify a waiver
of) require ments of en viionmental laws that are determined
to be Federal or more stringent State applicable or relevant
and appropriate requirements.
Hen.* N'on-Anuemis Phase Liquid (DNA PL) - DNAPLs
are immiscible hydrocarbon liquids that are denser than
water, such as chlorinated solvents (either as a single
component or as mixtures of solvents), wood preservative
wastes, coal tar wastes, PCBs and some pesticides.
DNAPLs can sink to great depths, can penetrate into
bedrock fractures, can move as a liquid in a direction
different from the flow of groundwater and can act as a
continual source of groundwater contamination over time.
Engineering Evaluation/Cost Assessment (EE/CA) -
An analysis of removal alternatives for non-time critical
removal actions.
Ex-Situ Treatment - Removal of material from the ground
for treatment.
Feasibility Study (FS) - A description and analysis of the
potential clean-up alternatives for a site. It is generally
conducted concurrently with the remedial investigation
(RI); together the studies are referred to as an RI/FS. (See
remedial investigation.)
In-Situ Treatment - The treatment or remediation of
media occurring in-place.
InnovativeTreatment Technologies-Technologies that
have been tested, selected, or used for treatment of
hazardous substances or contaminated materials but lack
well-documented costand performance data underavariety
of operating conditions.
Land Disposal Restrictions (LDRs) - The Hazardous
and Solid Waste Amendments (HSWA) to the Resource
Conservation and Recovery Act (RCRA) include specific
restrictions on the land disposal of RCRA hazardous
wastes. These restrictions, known as LDRs, prohibit the
land disposal of restricted RCRA hazardous wastes unless
these wastes meet treatment standards specified in 40CFR
268 or other compliance options.
Lieht Non-Aqueous Phase Liquids (LNAPL) - Like
DNAPLs. LNAPLs are immiscible liquids, but are lighter
than waterand therefore float on water. As they are lighter
than water, they are most frequently found at the ground-
water table/vadoze zone interface.
Record of Decision (ROD) - A public document that
explains the basis for selecting the clean-up altemative(s)
that will be taken or served under CERCLA.
Remedial Design (RD) -The remedial action that involves
designing and testing to determine whether the remedy
will be effective at a site.
Remedial Investigation (RI) - An in-depth study designed
to gather the data necessary to determine the nature and
extent of the threat posed by contamination at a Superfund
site. It also helps to establish the preliminary criteria for
cleaning up the site in the FS and supports the technical
and cost analyses of the alternatives. It is generally
completed and combined with the FS and referred to as the
RI/FS.
Risk Assessment - The qualitative and/or quantitative
evaluation performed in an effort to define the risk posed
to human health and/or the environment by actual and
potential exposures to specific pollutants in air. water, soil
or other media.
Superfund-Accelerated Cleanup Model (SACM) - An
initiative designed to accelerate all aspects of the Superfund
clean-up process.
Vadose Zone - The zone in soil that lies above the
permanent water table.
Volatile Organic Compounds (VOCs) - Any organic
compound which readily dissipates into the air.
24
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REFERENCES
Primary Reference:
U.S. EPA (In-Progress). Contaminants and Remedial
Options at Solvent Sites.
Compound Properties:
RREL Treatability Data Base - Available through
ATTIC (Contact Glenn Shaul (513) 569-7408)
General Site Investigations:
U.S. EPA, 1986. A Compendium of Superfiind Field
Operation Methods. EPA/540/87/001.
U.S. EPA. 1988. Guidance for Conducting Remedial
Investigations and Feasibility Studies Under
CERCLA. EPA/540/G-89/004, October.
U.S. EPA, 1989. Guide for Conducting Treatability
Studies Under CERCLA, Interim Final. EPA/540-2-89/
058.
U.S. EPA, 1991. Soil Sampling and Analysis for Volatile
Organic Compounds. EPA/540/4-91/001.
Incineration:
Dempsey, C.R. and Oppett, E.T., "Incineration of
Hazardous Waste: A Critical Review Update",
International Journal of Air Pollution Control and
Hazardous Waste Management, Volume 43, January
1993, pp. 25-73.
U.S. EPA, 1990. Mobile/Transportable Incineration
Treatment Engineering Bulletin. EPA/540/2-90/014,
February.
Presumptive Remedies:
U.S. EPA (In-Progress). Presumptive Remedies: Policy
and Procedures.
U.S. EPA (In-Progress). Presumptive Remedies:
Remedial Strategy and Treatment Technologies for
CERCLA Sites with Contaminated Groundwater.
Soil Vapor Extraction:
U.S. EPA, 1991. Soil Vapor Extraction Technology
Reference Handbook. EPA/540/2-91/003, February.
U.S. EPA, 1991. In-Situ Soil Vapor Extraction
Treatment Engineering Bulletin. EPA/540/2-91/006,
May.
U.S. EPA, 1991. Guide for Conducting Treatability
Studies Under CERCLA: Soil Vapor Extraction.
EPA/540/2-91/091A, September.
U.S. EPA, 1992. A Technology Assessment of Soil
Vapor Extraction and Air Sparging. EPA/600/R-
92/173, September
Thermal Desorption:
U.S. EPA. 1991. Thermal Desorption Treatment
Engineering Bulletin. EPA/540/2-91/(X)8, February.
U.S. EPA, 1991. Guide for Conducting Treatability
Studies Under CERCLA: Thermal Desorption
Remedy Selection - Interim Guidance. EPA/540/R-
92/074'A. September.
Additional References:
U.S. EPA, 1991. A Guide to Principal Threat and Low
Level Threat Wastes. Superfund Publication
9380.3-06FS.
U.S. EPA, 1991. Risk Assessment Guidance for
Superfund, Volume I: Human Health Evaluation
Manual. Part A. EPA/540/1-89/002, December.
U.S. EPA, 1989. Risk Assessment Guidance for
Superfund, Volume II: Environmental Evaluation
Manual. EPA/540/1-89/001. March.
U.S. EPA, 1991. Compendium of CERCLA ARARs
Factsheets and Directives. EPA Publication
9347.3-15, October.
25
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-------
United States
Environmental Protection
Agency
Off fee of
Sotid Waste and
Emergency Response
Directive No. 9355.0-63FS
EPA 540/F-96/008
PB 96-963308
July 1996
User's Guide to the
VOCs in Soils
:ive
Office of Emergency and Remedial Response
User's Guide
In order to expedite remedy selection at similar types of sites, EPA recommends the use of presumptive remedies—preferred
technologies for common categories of sites, based on historical patterns of remedy selection and EPA's scientific and
engineering evaluation of performance data on technology implementation. This User s Guide recommends the soil vapor
extraction (SVE) technology as the preferred presumptive remedy for sites where volatile organic components (VOCs) are
present in soil and treatment is warranted, although the thermal desorption and incineration technologies may be selected as
presumptive remedies at sites where conditions are appropriate. Presumptive remedies are expected to be used at all
appropriate sites except under unusual site-specific circumstances. This guide is based on the VOCs in Soils Presumptive
Remedy Guidance, Presumptive Remedies: Site Characterization and Technology Selection for CERCLA Sites with Volatile Organic
Compounds in Soils, OSWER 9355.0-48FS. Please refer to that guidance for a more detailed description of how the presumptive
remedy can be applied at sites where volatile organic components (VQCs) are present in soil.
In addition, the steps of assembling technologies into
alternatives and reducing alternatives are streamlined since
the number of technologies under consideration have been
minimized. Figure 1 presents the presumptive remedy
technologies for VOCs in soils and important features of
each.' -.• -'-.'••' . .-.'-"-': '"•• • . .-• '.-•'.-
PURPOSE
Jhis User's Guide is intended to aid the site manager. It:
• Explains the benefits of using the "presumptive
remedy approach"; ; , •
• Highlights how to decide if the presumptive
remedy approach can be applied to your site;
• Explains which presumptive remedy approach to
select for your site (the preferred presumptive
remedial alternative for sites with VOCs in the
soils is soil vapor extraction (SVE));
• Describes how to write the feasibility study (FS) or
engineering evaluation/cost analysis (EE/CA) for
a presumptive remedy; and
• Outlines administrative record requirements.
WHY USE THE PRESUMPTIVE
REMEDY APPROACH?
Time and cost savings can be realized "by following the
presumptive remedy approach during a remedial
investigation/feasibility study (RI/l^);F^t; since a preferred
cleanup technology can be identified prior to or early in the
RI, technology-specific remedial design data can be collected
and analyzed sooner- In addition, use of the presumptive
remedy approach eliminates the need to:
. • Identify potential treatment technologies
• Screen technologies in your site-specific FS or
EE/CA.
Figure 1. Presumptive Remedies for VOCs in Soils
Soil Vapor Extraction (SVE): The preferred
presumptive remedy
• In-situ process
• Removes contaminants from vadose zone
soils by inducing air flow through the soil
• Highly cost effective alternative
• Vapor treatment may be required
Thermal Desorption
• Soil excavation required
• Uses direct or indirect heat to vaporize VOCs
from soil
• Vapor treatment may be required
Incineration
• Soil excavation required
• Employs thermal decomposition via oxidation
• Destroys the organic fraction of the waste
• Vapor treatment may be required
-------
CAN YOU APPLY THE VOCS IN SOILS PRESUMPTIVE REMEDY;APPROACH|TO;YOUR!SITE^
In order to determine if you can use the presumptive remedy
approach at your site, you need to answer the following
questions. Regardless of the status of your RI or removal
evaluation, these questions can be addressed once you
establish the nature of any VOC and non-VOC waste
contained in the soil, where treatment is warranted.
Are VOCs present in soil or sludge?
VOCs include halogenated and non-halogenated organics
such as trichl6roethylene, carbon tetrachloride, acetone and
benzene. A complete a list of typical VOCs is found in the
master VOCs presumptive remedy guidance referenced on
^ page 1. If your site does not have VOCs in the soil, then this
User's Guide is not applicable for use in remedy selection at
the site.
Are non-VQCs present that will preclude the use of
the presumptive remedy guidance?
For sites with a mixture of VOCs and other contaminants in
soil, the presumptive remedies should be considered only if
they also can also be effective in removing the non-VOC
contaminants, or can be used in combination with other
remedies. For combination remedies, this presumptive
remedy approach canbe used to select the VOC portion of the
remedy. For example, sites with VOCs and metals
commingled in soil may be effectively remediated by
employing SVE to remove VOCs and fixation or solidification
to address the metal contamination. The presumptive remedy
approach can still be used for the selection of the SVE rerr
whereas a traditional FS analysis would be necessary fot
treatment of metals.
In conclusion, if VOCs are present in soils and non-VOCs do
not preclude a VOC remedy, you may also select the
presumptive remedy for the VOC component of the site.
Have all key stakeholders been notified?
Please keep in mind that it is important to notify the
community, (especially any community working groups)
the State, and any PRPs that a presumptive remedy is being
considered at your site. It is important to get their buy-in
early in the cleanup process.
This notification should begin as early as possible and can
continue to occur throughout the RI/FS in the form of fact
sheets and agenda items during public meetings. Early
disaissionsaboutmerationaleforpi^urr^tiveremediescreates
. confidence inboththetechnology and remedyselectionprocess.
Once a candidate presumptive remedy site has been
identified and a response action involving treatment is
warranted under the NCP, you can decide which of the 3
VOCs in soils presumptive remedy technologies to select.
WHldH VOCs IN SOILS PRESUMPTIVE REMEDY IS:BEST FOR MYjiSITE?
If SVE is determined to be ineffective based on site-specific
circumstances, thermal desorption is the next technology that
should be assessed for use at your site. Thermal Desorption is
the primary VOC presumptive remedy at sites where sod
exdavation is required to remediate a non-VOC contaminant.
At some sites, public perception is that incineration can be
disruptive to a community, and it has been ruledoutdue to that
perception. Be aware of this if you prove incineration as a
remedy. For a complete discussion of the characteristics that
affect the use of SVE, thermal desorption and incineration
technologies, refer to Tables 3 and 4 of the master VOC
presumptive remedy guidance.
Once you have determined that your site is a candidate for a
presumptive remedy, SVE should be analyzed first since it is
the preferred presumptive remedial alternative. In most,
cases, SVE is extremely cost effective and can be implemented
in-situ. The SVE Checklist (Figure 2) can help you decide if
SVE is appropriate at your site1. The questions posed in the
SVE Checklist provide a preliminary "first-cut" assessment
of basic site characteristics that relate to potential SVE
treatment effectiveness. Your site is a strong carididate for
SVE if you answer "yes" to all of these questions. At this
point, you may wish to assume SVE as the preferred
technology for VOC remedial action at your site. Therefore,
you may immediately proceed to an SVE Pilot Study and a
Presumptive Feasibility Study (see p. 3).
For the purposes of this Users Guide, the terms "Presumptive
FS or EE/CA" refer to the FS or EE/CA developed at sites
where the presumptive remedy is applied. The SVE Checklist
is not a definitive screening test for SVE. So, even if you
answer "no" to one or more of these questions, SVE may still
be an appropriate presumptive technology for your site, but
greater technical analysis may be warranted. Considerations
such as best professional judgment and community opinion
should guide your decision to proceed with an SVE Pilot
Study to confirm the appropriateness of the SVE technology
at your site.
'If you are scoping an RI or a removal evaluation, the information requested in Figure 2 should be identified as a "
need- along wUh common data needs for an RI/FS. As you develop the RI/FS Work Plan, you should estab'f
objectives for each set of RI data needs. All presumptive remedy data needs should be collected dunng the first round of
data collection of the RI if not before. cv,.,,Q
»See Table 4 of the VOCs in Soils Presumptive Remedy Guidance for a description for each of the terms listed in Figure
Figure 2. SVE Checklist
Site Characteristics2
Soil Permeability > 1Q-* cm2
Soil Moisture Content < 50%?
VOC Vapor Pressure > 0.5mm Hg?
Dimenstonless Henrv's constants > 0.01?
Soil/Air Filled Porosity < 40%?
Low organic carbon content <
Yes
No
-------
After determining that your site can use a VOCs in soils
presumptive remedy, the next step is to p repare a presumptive
"S or EE/CA. Note that for non-time-critical removals, you
can prepare an EE/CA. Regardless of the status of your RI
or removal evaluation, the Presumptive FS or EE/CA for the
soil remedy should begin immediately:
As highlighted on page 1, the presumptive remedy approach
allows you to streamline and focus the FS or EE/CA by
eliminating the technology screening step because EPA has
already conducted this step onagenericbas is in the document
Feasibility Study Analysis for VOCs in Sails Sites. Basically,
only the "No- Action" alternative and presumptive remedy
alternative require further consideration. If SVE is
appropriate, the other presumptive technologies (thermal
desorption and incineration) may be eliminated from further
consideration. To tailor the Presumptive FS to the specific
conditions at your site, you may first need to refine the
presumptive remedy alternative, as necessary. Forexample,
if off gas treatment is required, the technology for off gas
treatment is not selected presumptively and should be
addressed in the FS. As shown in Figure 3, the presumptive
technology should be matched with an appropriate mix of
conventional and innovative vapor treatment technologies.
The final step of the Presumptive FS would consist of
analyzing the No-Action and Presumptive Remedy
alternatives against the. nine NCP evaluation criteria.,
An example format for critical elements of a Presumptive FS
is provided in Figure 4. Please note that it is advisable to
•pand the Introduction Chapter of your Presumptive FS or
uE/CA to include a brief discussion of the presumptive
remedy approach and justification for using this approach at
your site.
You may wish to consider technologies that enhance the
performance of the presumptive remedy based on site-
specific conditions. For example, SVE enhancements include
bioventing, ca'pping, hot air injection, steam injection, and
subsurface mining. Additionally, you may consider using a
phased approach to designing and implementing an ^VE
system similar to EPA's suggested phased approach to
characterizing and remediating contaminated groundwater
sites. In order to maximize engineering flexibility during
remedial design and remedial action, it isnotalways necessary
to address potential enhancements in your Presumptive FS.
Only where: (a) there is a high degree of confidence that the
enhancement is essential for cost-effective remediation; or,
(b) the addition of the enhancement significantly changes the
cost or scope of the base SVE alternative, should such
enhancements be included in the Presumptive FS. For more
information on whether to include enhancements in your FS
and determining what would require changes to a ROD, see
"Guide to Addressing Pre-ROD and Post-ROD changes,
OSWER 9355.3-Q2FS-4, April 1991.
Figure 3. Example of a Possible SVE
Alternative Refinement
Alternative 1 - No Action
Alternative 2 - SVE with No Off Gas Treatment
Alternative 3 - SVE with Off Gas Treatment (e.g. acti-
vated carbon, catalytic oxidation, flameless thermal oxi-
dation, resin adsorption, etc.)
Alternative 4 - SVE with Off Gas Treatment and Capping
Figure 4. Example Format For
Critical Elements of A Presumptive FS
I. Introduction ,
A.' Background to the Site
B.'' Introduction to the Presumptive Remedy
Approach
C. Determination to use the Presumptive Remedy
Approach
II. Description of trie No Action Alternative, the
Presumptive Remedy Alternatives, and ARARs
III. Detailed (Nine Criteria) Analysis of the No Action
Alternative and the Presumptive Remedy Alternative
IV. Description of the Preferred Alternative
A. Rationale for the Preferred Alternative
You must compile an administrative record in accordance
with the Final Guidance on Administrative Records for Selecting
CERCLA Response Actions, OSWER Directive 9833.3A.I. The
administrative record must contain both EPA guidance and
site-specific information documenting1 the selection of the
VOCs in soils presumptive remedy. Other required EPA
guidance documents include:
• Presumptive Remedies: Policiesand Procedures, OSWER
9355.0-47FS
• Presumptive Remedies: Site Characterization and
Technology Selection for CERCLA Sites with VOCs in
Soils, OSWER 9355.0-48FS
Feasibility Study Analysis for VOCs in Soils Sites, OSWER
9356.0-01. [Note: The administrative record file index
should include a notice specifying the location of and
times when public access is available to the generic file
of backup materials used in developing this document.
The generic file contains background materials such as
technical references and previous feasibility studies.
Each EPA Regional office has a copy of this file.)
"Guide to Principal Threat and Low Level Threat Wastes,"
OSWER 9380.3-06FS
-------
-------
United States
Environmental
Protection
Agency
Office of Directive No. 9355.C
Solid Waste and EPA 540-F-97-OCW
Emergency Response PB97-963501
April 1997
Presumpti^ Remedy:
United States Air Force
Air Combat Command
Supplemental Bulletin
Multi-Phase Extraction (MPE)
Technology for VOCs in
Soil and Groundwater
Quick Reference Fact Sheet
This Quick Reference Fact Sheet is issued jointly by the U.S. EPA and Air Combat Command (ACC) of
ieUnSed States Air Force (USAF) to provide information on the Multi-Phase Extracfon (MPE) technology
oTertraetion of volatile organic compounds (VOCs) present in soil and groundwater. Th.s fact sheet
recomS MPE as a potentially valuable enhancement for the SVE option under the presumptive
remedy for sites with VOCs in soils;
PURPOSE
This Fact Sheet will:
Provide an explanation of the MPE
technology; ,
Explain how to determine if MPE is
applicable to your site;
Explain how to select between the
three MPE applications;
Discuss the advantages and
disadvantages of the MPE
applications;- ;,.:..
provide contaminant extraption
costs for MPE; and
ahd
^ ; ^coniacttPOCs) for more information
'' ' onMPE. '"' -.•'.• '''' ' '"' '
BACKGROUND
Presumptive remedies are preferred
technologies for common categories of sites
based on historical patterns of remedy
selection and U.S. EPA's scientific and
engineering evaluation of performance data
on technology implementation. By
streamlining site investigation and
accelerating the remedy selection process,
presumptive remedies are expected to
ensure the consistent selection of remedial
alternatives and reduce time and costs
required to clean up similar sites.
Presumptive remedies are generally
expected to be used at all appropriate sites;
however, site-specific circumstances dictate
whether a presumptive remedy is
appropriate at a given site. The U.S. EPA
has established presumptive remedies for
sites with soils contaminated by VOCs. The
U.S. EPA guidance documents on these
presumptive remedies are Presumptive
Remedies: Site Characterization and
Technology Selection for CERCLA Sites with
Volatile Organic Compounds in Soils,
OSWER 935S.Q-48FS and User's Guide to
the VOCs in Soils Presumptive Remedy.
-------
This fact sheet is a supplemental bulletin for
the VOC Presumptive Remedy. It is intended
to provide site managers with recent
information that may be useful in making
decisions about the specific type of
• extraction technology to employ at a VOC,
presumptive remedy site.
What is MPE Technology?
The MPE process was developed for the
remediation of VOCs and other contami-
nants in low to moderate permeability
subsurface formations. The process is a
modification of the conventional soil vapor
extraction (SVE) technology. Traditional SVE
is the process of stripping and extracting
volatile compounds from the soil by inducing
air flow through the soil. Soil vapor flow is
induced by applying a vacuum to extraction
wells. Generally, SVE is applied to soil
above the groundwater table.
MPE is an enhancement of the traditional
SVE system. Unlike SVE, MPE simultane-
ously extracts both groundwater and soil
vapor The groundwater table is lowered in
order to dewater the saturated zone so that
the SVE process can be applied to the newly
exposed soil. This allows the volatile com-
pounds sorbed on the previously saturated
soil to be stripped by the induced vapor flow
and extracted. In addition, soluble VOCs
present in the extracted groundwater are
also removed.
MPE is a generic term for technologies that
extract soil vapor and groundwater, simul-
taneously. Under this generic term, this fact
sheet presents two technologies, the two-
phase extraction technology (TPE) and the
dual-phase extraction technology (DPE).
Both technologies extract groundwater and
soil vapor from a single well. You can .
consider MPE as a tool for VOC remediation
as illustrated in Highlight 1.
The TPE technology employs a high vacuum
(approximately 18 to 26 inches of mercury)
pump to extract both groundwater and soil
vapor from an extraction well. A suction pipe
is lowered into the extraction well to extract
the soil vapor and groundwater from the
subsurface. A typical two-phase type system
is illustrated in Figure 1.
For some TPE methods, turbulence
generated within suction pipe facilitates the
transfer of aqueous phase contaminants to
the vapor phase (up to 98% stripping).
By comparison, the DPE technology
employs a submersible or pneumatic pump
to extract the groundwater, and a high „•
vacuum (approximately 18 to 26 inches of
mercury) or low vacuum (approximately 3 to
12 inches of mercury) extraction blower is
used to extract the soil vapor as illustrated in
Figure 2. For DPE wells using submersible
pump, a sump is installed at the bottom of
the well to prevent cavitation of the
submersible pump. Under vacuum
conditions, a net positive suction head may
be maintained, to prevent cavitation of the
submersible pump, using a standing water
coiumn. Under high vacuum conditions, a
sump as deep as 20 feet may be required to
provide, proper water column at the pump.
intake. " •,•'•-•
Note that some specific hardware and well
configurations associated with the MPE
technologies are patented. In those cases,
potential users should contact,the patent
owners about the patent owner's licensing
Highlight 1
Multi-Phase Extraction (MPE) - A remediation
tool for simultaneous extraction of VOC
contaminated soil vapor and groundwater.
The two types of MPE are:
• Two-Phase Extraction (TPE)
. tow or High Vacuum Dual-Phase extraction
(DPE) ,
-------
requirements. Description, or use of specific
products, methods or companies does not
constitute an endorsement by the USEPA or
the U.S. Air Force's Air Combat Command.
Is MPE Appropriate at my Site?;
Once you have determined that your site is a
candidate for a presumptive remedy using
. ,the VOC User's Guide, you must determine
;i jfMPE can be implemented to treat the VOC
'dbnfaminated media at your site. MPE is
most cost effective for cleaning up low to
moderate permeability sites with
halogenated VOC contamination in the soil
and groundwater. MPE is also effective at
cleaning up sites contaminated with non-
halogenated VOCs and total petroleum
hydrocarbons (TPH). MPE may be
particularly useful when expedited cleanups
are necessary.
When considering use of MPE, it is
important to choose an engineering firm that
has experience implementing the MPE
technologies. Prior to implementation, a
treatability pilot study should be performed
and the results evaluated to maximize the
effectiveness of the MPE technology
selected.
To determine if the MPE technologies may
be effective at your site, compare your site
conditions to the guidelines presented in
Table 1. These guidelines provide a
preliminary assessment of the basic site
characteristics that relate to MPE treatment
effectiveness. The MPE technologies are
generally applied below the water table.
They also may be applied above and below
the water table simultaneously. Note that if
you wish to apply MPE above the water
table, your site should also meet the air
permeability guidelines. If your site
conditions meet these guidelines, then your
site is a candidate for MPE. At this point you
may wish to select one of the MPE
technologies as the preferred technology for
VOC remedial action at your site and
proceed with a treatability pilot study. These
guidelines are not a definitive screening test
for MPE. So, even if one of your site
conditions does not meet these guidelines,
MPE may still be an appropriate technology
for your site, but greater technical analysis
may be warranted. An engineering
evaluation, by experienced professionals,
should guide your decision to proceed with
an appropriate MPE treatability Pilot Study to
confirm the applicability of the MPE
technologies.
Tabie 1. MPE General Guidelines
Site Conditions
Contaminant
, Contamination location
Henry's Law Constant of majority of
contaminants
Vapor pressure of majority of contaminants
Geology below qroundwater table
Guideline
1. Halogenated VOCs.
2. Non-Halogenated VOCs and/or Total
Petroleum Hydrocarbons (TPH).
1. Below groundwater table.
2. Both above and below groundwater table.
> 0.01 at 20 C2 (dimensionless)3
> 1 .0 mm Hg at 20 Ce
Sands to Clays
MPE application above the groundwater table
Air permeability of soil above the groundwater
Moderate and low permeability (k< 0.1 darcy")
soils.
' Dimenstonless Henry's Law Constant in the form: (concentration in gas phase) / (concentration in liquid phase)
5 Soil Gas permeability (k): 1 darcy = 1 x 10'8cm2
-------
The effectiveness of the MPE technologies
are directly dependent on site characteristics
including geologic, hydrogeologic, and
contaminant characteristics. The MPE
technologies tend to be less effective under
conditions outside of the guidelines shown
above. MPE has shown to be less effective
for sites that have very high permeabilities
and lithologies consisting primarily of gravels
or cobbles. For effective MPE, the aquifer
must be able to be dewatered. Sites with
extremely high groundwater flow rates may
be not as suitable for MPE. MPE is not
recommended for sites where the target
contaminants are not volatile compounds
(i.e. inorganic and semi-volatile).
Which Type of MPEJs; Best ;f or, my Site?
Once you have determined that a MPE
technology will be effective at your site, you
must determine which variation of MPE will
be most effective for contaminant removal.
All of the MPE technologies; low-vacuum
DPE (LVDPE), high-vacuum DPE (HVDPE),
or TPE, have optimum site conditions where
they are considered to be the most cost
effective for VOC contaminant removal. To
determine which MPE technology will be
most effective at your site, compare your site
conditions to the guidelines presented in
Table 2. These guidelines provide a
preliminary assessment of the basic site
characteristics that relate to potential
treatment effectiveness of LVDPE, HVDPE,
and TPE.
Table 2. MPE Technology Selection Guide: LVDPE, HVDPE, or TPE
Site
Conditions
Groundwater production
ratej
Maximum depth of
targeted contamination
Geology below
qroundwater table
LVDPE
Guideline
not limited by
typical groundwater
production rate,
however aquifer
must be able to be
dewatered.
not limited by depth
of contaminant
Sands to silty sands
HVDPE
Guideline
not limited by
typical
groundwater
production rate,
however aquifer
must be able to
be dewatered.
Not limited by
depth of
contaminant
Sandy silts to
clays
TPE
Guideline
< 5 gpm
1. Up to 50V feet below
ground surface fags
(for groundwater
production < 2 gpm).
2. Up to 20-30 feet bgs
(for groundwater
production
between 2 and 5
qpm).
Sandy silts to clays
For MPE application above the groundwater table
Air permeability of soil
above the groundwater
table.
Moderate
permeability
, (greater than 1 x
10'3darcv)
Low
permeability
(less than 1 x
10'2darcy)
Low permeability (less
thanl x10'2darcy)
a For MPE, the aquifer must be able to be dewatered.
-------
Generally, the high vacuum (approximately
18-26 inches mercury) applications, HVDPE
and TPE, are most cost effective where the
target geologic formations have low
permeabilities (i.e., sandy silts to clays). Both
HVDPE and TPE will be effective at depths
less than 50 feet BGS with low ground water
production rates (<5 gpm). However,
HVDPE has a broader range of application
and may also be applied at greater depths
and higher flow rates.
The low vacuum (3 to ,12 inches of mercury)
application, LVDPE, is suitable for more
permeable soils (i.e., sands to silty sands).
LVDPE is not limited by depth of
commitment or typical groundwater flow
rates, however the aquifer must be able to
be dewatered. Generally MPE is applied
below the groundwater table. However, MPE
may also be applied simultaneously above
and below the water table. Where MPE is to
be applied above the groundwater table, the
air permeability must also be considered.
Figure 3 presents a decision logic flowchart
that may assist you in the selection of
LVDPE, HVDPE, or TPE.
Prior to implementation of the chosen MPE
technology, a treatability pilot study should
be performed by an experienced engineering
firm. Proper interpretation of the pilot study
results are needed to maximize the
effectiveness of MPE.
Gase Studies airtdi§@£lti
The MPE technology has been applied at
dozens of low to moderate permeability sites
and has consistently proven to be more
effective at removing subsurface VOCs than
conventional pump-and-treat or soil vapor
extraction systems alone. This is due to the
increase in groundwater and contaminated
soil vapor removal rates, and the
volatilization of contaminants in the
previously saturated soils. The increased
mass removal rates result in decreased total
Removal costs. Note that the effectiveness of
the MPE technologies are directly dependent
'on site characteristics (geologic,
hyrogeologic, and contaminant
characteristics, etc).
Pilot study and/or full-scale MPE system
field data, demonstrating the
effectiveness of MPE at multiple military
sites (including McClellan AFB, Travis AFB,
Nellis AFB, FE Warren AFB, Offutt AFB,
Ellsworth AFB, DDRW-Tracy Depot, and Air
Force Plant-44 [AFP-44]) are currently
available. Appendix A presents the results of
selected case studies. Appendix A also
includes estimated full-scale contaminant
extraction costs, presented in dollars per
pound of contaminant removed ($/lb), for
each of the case studies. These costs are
based on a single well extraction system
operated for one year. They include capital
costs, installation costs and operation and
maintenance costs. The costs do not include
design, well installation, or soil
vapor/groundwater treatment costs. These
costs also do not include any costs
associated with patent requirements. As
demonstrated in Appendix A, the
contaminant extraction costs for MPE
applications are highly site-specific. It is
dependent upon the original and target
clean-up level concentrations of
contaminants, aquifer/vadose zone
characteristics, groundwater and vapor
flowrates, as well as the design and
operation of the technology used.
-------
The key to designing an effective MPE
system is experience and performing a
treatability pilot study beforehand. Pilot study
results provide key parameters, such as
effective well vacuum, groundwater and
vapor radii of influence, and groundwater
and soil vapor extraction flowrates. These
parameters are essential for the selection
and design of vacuum pumps, submersible
pumps, and eventually, groundwater and
vapor treatment.
Because TPE and HVDPE application
parameters overlap, other site parameters
will also affect your decision on which MPE
technology to use. The ability to use existing
extraction wells at a site may.be the key
factor in deciding to use HVDPE or TPE.
Table 3 provides the advantages and
disadvantages of HVDPE, LVDPE, TPE
which may assist you in final selection of a
MPE technology.
Advantages
Disadvantages
Between HVDPE/LVDPE and TPE
HVDPE and LVDPE
No limitation on depth of targeted
contamination.
Lower vacuum losses within extraction
well.
No limitation on groundwater production
rate.
Where submersible pumps are used, a
standing water column above the pump
is required, therefore, installation of a
new extraction well with a sump may be
required.
More controls required for pump as
compared with TPE.
TPE
Groundwater stripping: up to 98%
transfer of aqueous phase
contaminants to vapor phase.
No pumps or mechanical equipment
required in well.
Can be applied at existing extraction
or monitoring wells.
Limited to a maximum groundwater
depth of approximately 50 feet below
ground surface.
Limited to a maximum groundwater
flowrate of approximately 5 gpm.
Higher vacuum losses due to lifting
water from the well.
-------
CONCLUSION
For sites with VOC-contamination in the soil
and/or groundwater and appropriate site
characteristics, MPE is a cost effective
technology. MPE has been applied at
dozens of low- to moderate-permeability
sites and has consistently proven to be more
effective at removing subsurface VOCs than
conventional pump-and-treat.or soil-vapor
extraction systems alone. For further
information or assistance on MPE
applications, refer to Table 4 for points of
contact or reference information.
Table 4. MPE Points-of-Contact and References
oints of
ontact
Site Contacts
Affiliation
DDRW-Tracy
Travis AFB
Neilis AFB
Title
Phone
Number
(209) 982-2086
Marshall Cloud Project Manager/
Environmental
Specialist
"Mar'k'Sandy " Remedial Program (707) 424-3172
Manager
Jim PedrickChief of Environmental (702) 652-6103
Restoration Division
McClellanAFB Kevin Wong Remedial ^Program (916)643-0830
Manager
Fi'Warren'AFB Barry'Mountain Chief of Missile (307)-775-2532
Engineering, _
mTsworthAFBJohnDeYre Remedial'progValn (605)385-2675
Manager _
Ofrutt AFB Phil Cork installation Restoration (402) 294-7621
WrighrPattereonAFB Dennis'Scott """ Remedaal'ProgSrn" (513) 255-0258
AFp.44) Manager JSiiZ
EPA Contacts U.S.EPA^adquarters ^cott Fredericks^^ ^
—•— _.—.——«-—«-•• • *• * u——i tiii*-i4 r^Vi^mict (703) o03~oo3o
U g EPA Headquarters M^?!?.??.: fJ™ - *-nerms..... ...x...::.../..::—
-•-U^ipTH-eadqu^^^ ^^^
ACC Contacts ACC Headquarters Margaret Program Manager (757)764-6249
Patterson . —
Fating U.S.EPA Guidance ^^'Presumptive Remedies: Site Characterization and Technology
Existing US*.rA uuioance Selection for CERCLA Sites with Volatile Organic Compounds in
Soils/ OSWERJt3J5JM8FS. -
- ^Presumptive Response"Strategy and Ex-Situ Treatment Technologies
for Contaminated Groundwater at CERCLA Sites," Final, October
1996, OSWER 9283.1-12.
"User7s Guide"to~me VOCs iri Soils Presumptive Remedy," April 1996.
-------
<=>
Vacuum
Gauge
Atmospheric.
Air Bleed Valve
To
Water Water
Pump Phase
Treatment
x=x
0
Liquid
Ring
Vacuum
Pump
To
Vapor
Phase
Treatment
Vadose Zone
Static Water Table
Suction Pipe ,,
NOTE: The extraction well may also be screened
above the saturated zone for treatment
of the vadose zone.
Figure 1. Schematic of a TPE System
-------
Vapor-Water
Separator
Groundwater plow
To Treatment & Disposal
Electrical
Control Panel
vadose Zone
Static Water Table
NOTE: The extraction well may also be screened
above the saturated zone for treatment
of the vadose zone.
Figure 2. Schematic of a DPE System (Low Vacuum or High Vacuum)
-------
Are
Non-Halogenated
VOCs or TPH Present in
the Groundwater
9
Are
Haiogenated
VOCs Present in the
Groundwater
9
MPE Is Not
Applicable
at This Site
Is
A Timely
Cleanup
Necessary
9
Other Technologies
May Be More Applicable
Is the
Depth to
Groundwater
<50 Feet bgs
9
Is the
Saturated Zone
Composed of Sandy
Silts to Clays
Is the
Saturated Zone
Composed of Sands
to Silty Sands
Can
Extraction
Well with Sump be
Installed
9
Are
Pneumatic Pumps
Applicable
Other Technologies
May Be More Applicable
Can
Extraction
Well with Sump be
Installed
Are
Pneumatic
Pumps
Applicable
Can
Aquifer be
Dewatered with
LVDPE
Data Suggests LVDPE
Should Be Applied
Is the
Vadose Zone
Contaminated
with VOCs
Permeability
of the Vadose Zone
Moderate (>1
Darcy)
Data Suggests LVDPE
wpl be Most
Effective Applied to
Both the Saturated Zone
and the Vadose Zone
Data Suggests LVDPE
will be Most
Effective Applied
to the Saturated
Zone Only
-------
Can
Aquifer be
Oewatered
with TPE
9
Is the
Groundwater
Rowrate
<5gpm
Data Suggests TPE
Shoi-id Be Applied
Can
Aquifer be
Dewatered with
HVDPE
9
'••2&&£>. 4r:&7fe?'^
....ZZMS-W; _j±: ••-•••'••••tV&X
^TPIEAefSlfcability
irnsFs*;^-^^,"- ? ""YjrjjS.
^ff;:«m
S»*y^
Data Suggests TPE
will be Most
Effective Applied
to the Saturated
Zone Only
S^S^a
a^Eiij
Data Suggests TPE
will be Most
Effective Applied to
Both the Saturated Zone
and the Vadose Zone
Data Suggests HVDPE
Should Be Applied
Is the
Permeability of
the Vadose Zone Low
<1 xlO'Darcy
9
Is the
Vadose Zone
Contaminated
with VOCs
Data Suggests HVDPE
will be Most
Effective Applied to
Both the Saturated Zone
and the Vadose Zone
Data Suggests HVDPE
will be Most
Effective Applied
to the Saturated
Zone Only
Figure 3.
MPE Selection Decision
Logic Diagram
-------
Appendix A. Summary ol Case Study Results
SITE
DDRW-Tracy
out
Travis AFB, MW
269
Travis AFB,
Ragsdala & V,
MW-7
Travis AFB,
OSA
Nellia AFB, Site
44
McClellan AFB,
Bld.666
FE Warren AFB,
OU2. EW1
Ellsworth AFB
OU-11.BG-04
OHull AFB, Bid.
301
McClellan AFB,
Bid. 360, EW-
321
McClellan AFB.
Bid. 380, MW-
224
Air Force Rant
44, IRPSileS.
Air Forco Plant
44, IRPSII82,
Air Force Plant
Trttlrotnt
Typ»
TPE
TPE
TPE
TPE
TPE
TPE
TPE
TPE
LVDPE
LVDPE.
HVDPE
LVDPE
""HVDP'E"
LVDPE
LVDPE
Dtpthol
W«tK
«(Mt
BQ8)
24.0
13.7
10.0
8.0
45.0
109.0
10.0
18
50.0
112.0
112.0
112.5_
i'lTs""
132.0
145.0
Uthology
VidoMZom
illty clay
tills, clayi
tills, day*
elltv day
silly day
sandy silt
dayty.
gravely, ttty,
sandy sIRy
day, dayoy
sand
day
days, sills
days, silts
aandy8jM__
sandy tilt
Interbedded
sandy gravel
& eandy day
Intefbedded
sandy gr avel
& sandy day
intetitoedded
sand
Saturated
ZOM
tiltyday
illli, days
silts, days
silly day
calidw, silly
d«y
sandy silt
clayey sands
and day
dayay graval,
plerre shale
ettysand
sandy silts,
stt&sand.
sandy silts,
sUtysand
San&aUL
"""sandy '*¥'
Mwbadded
sandy grave
& sandy day
(nterbedded
sandy grave
& sandy day
inlertaeddod
sand
TirgttKi
Conbunlnwt
TCE
TCE
TCE.TPH,
Benzene
TCE. PCE
TCE (VOCs)
TCE, PCE,
Freon
TCE
TCE
TCE
TCE (VOCs)
TCE (VOCs)
TCE (VOCs)
TCE (VOCs)
TCE.DCE,
TCA. Freon
113
TCE
TCE. DCE
Groundvrtttr
ConcsntrstlMi
(pgft)
3.5-6.5
1.030
3,700
900
1.760
8,400
0-150
40.5
24,600
10,500
10,500
11,000
11,000
190-510
240-2,100
25-58
Jurob»rcf
Mmctlon
Wells
1
1
1
1
1
1
1
1
1
1
i
1
1
1
1
1
Dtpthol
Extortion
Well
((MtBQS)
31
22.5
29
29
60
124.5
25
33
92
160
161
119.5
119.5
175
250
180
EtfKllvt
Wsll
Vacuum
(In. of HO)
18
19-22
17
22.5
6.5
20
9-13
9-14
9-14.5
10
15
10
24
6.5
6
6
8crt«ned
tnttrval
(fettBQS)
15.5-30.S
11.7-21.7
8.5-28.5
8-28
30-60
1055-124.5
12.7-24.7
13-23
50-70
110-140
110-140
110-140
109.5-119.5
42-184
120-245
120-150
InMW Tolsl Miss of
VOCs Rtmovtd
(tbs/diy)
MPE
2.5x10°
0.113
24
0.875
0.39
9
0.029
0.003
0.7
11.4
13.6
0.68
2.54
177
735
23.5
P*f
8.7x10''
0.008
0.29 -
0.11
0.012
0.36
0.011
0.001
0.33
0.28
0.28
0.08
0.08
0.21
1.55
0.032
Oroundwitir Flow rate
(GPH)
MPE
3.5
3.72
5
0.5
1.7
5.2
2.7-3.0
2-3
3.1
5.9
6.7
1.6
1.8
58
112
69
P4T
0.5
0.8
2
<0.25
0.8
4
2-3
<2gpm
(estimated)
1.5
2.75
2.75
0.6
0.6
47
110
64
Vapor
Flow r»U
(sefm)
13-17
6-10
17
3.5-5
87-97
94
2-4
15-30
9-14.5
58
78
4.5
11
231
181
EitlmtUdCoitol
ConUmlrunt
Extraction (Mb)
38,000
848
4
110
351
58
3.300
32,000
137
245
225
1,700
1,290
3
<1
Refitirkt
a
b
c
"*,
a
d
e
e
1
1
Remarks:
a. High contaminant removal costs are due to low groundwater concentrations.
b. Test results indicate that LVDPE would be more effective than TPE at this site.
c. Test results indicate that HVDPE would be more effective than TPE at this site.
d. Test results indicate that HVDPE would be more effective than LVDPE at this site.
e. HVDPE and LVDPE shown to be nearly equally cost effective lor EW-321 at McClellan
f. HVDPE shown to be most cost effective for MW-224 at McClellan. .
N/A = Not applicable
Note: Costs associated with any patent requirements are not included in the cost.
-------
United Slates
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Oirectwe No. 9355.Q-49F5 I
EPA S40-F-93-035 I
PB 93-963339 i
September 1993
Presumptive Remedy for
CERCLA Municipal Landfill
Sites
Office of Emergency and Remedial Response
Hazardous Site Control Division 5203G
Quick Reference Fact Sheet
Since Superfund's inception in 1980, the remedial and removal programs have found that certain categories of sites have
similar characteristics, such as types of contaminants present, types of disposal practices, or how environmental media
are affected. Based on information acquired from evaluating and cleaning up these sites, the Superfund program is
undertaking an initiative to develop presumptive remedies to accelerate future cleanups at these types of sites. The
presumptive remedy approach is one tool of acceleration within the Superfund Accelerated Cleanup Model (SACM).
Presumptive remedies are preferred technologies for common categories of sites, based on historical patterns of remedy
selection and EPA's scientific and engineering evaluation of performance data on technology implementation. The
objective of the presumptive remedies initiative is to use the program's past experience to streamline site investigation
and speed up selection of cleanup actions. Over tune presumptive remedies are expected to ensure consistency in remedy
selection and reduce the cost and time required to clean up similar types of sites. Presumptive remedies are expected to
be used at all appropriate sites except under unusual site-specific circumstances.
This directive establishes containments the presumptive remedy for CERCLA municipal landfills. The framework for
the presumptive remedy for these sites as presented in a streamlining manual entitled Conducting Remedial Investiga-
tions/Feasibility Studies for CERCLA. Municipal Landfill Sites, February 1991 (OSWER Directive 9355. 3-11). This
directive highlights and emphasizes the importance of certain streamlining principles related to the scoping (planning)
stages of the remedial investigation/feasibility study (RI/FS) that were identified in the manual. The directive also
provides clarification of and additional guidance in the following areas: (1) the level of detail appropriate for risk
assessment of source areas at municipal! landfills and (2) the characterization of hot spots.
BACKGROUND
Superfundhasconducted pilot projects at four municipal
landfill sites1 on the National Priorities List (NPL) to
evaluate the effectiveness of the manual Conducting
Remediallnvestigations/FeasibilityStudiesforCERCLA
Municipal Landfill Sites (hereafter referred to as "the
manual") as a streamlining tool and as the framework for
the municipal landfill presumptive remedy. Consistent
with the National Oil and Hazardous Substances Pollution
Contingency Plan (or NCP), EPA's expectation was that
containment technologies generally would be appropriate
for municipal landfill waste because (he volume and
heterogeneity of the waste generally make treatment
impracticable. The results of the pilots support this
expectation and demonstrate that the manual is an
effective tool for streamlining the RI/FS process for
municipal landfills.
'Municipal landfill site* typically contain acombtnation of principally
municipal and to a lesser extent hazardous wastes.
Since the manual's development, the expectation to
contain wastes at municipal landfills has evolved into a
presumptive remedy for these sites.2 Implementation of
the streamlining principles outlined in the manual at the
four pilot sites helped to highlight issues requiring
further clarification, such as the degree to which risk
assessments can be streamlined for source areas and the
characterization and remediation of hot spots. The
pilots also demonstrated the value of focusing
streamlining efforts at the scoping stage, recognizing
that the biggest savings in time and money can be
realized, if streamlining is incorporated at the beginning
of the RI/FS process. Accordingly, this directive
addresses those issues identified during the pilots and
highlights streamlining opportunities to be considered
during the scoping component of the RI/FS.
'See EPA Publication 9203.1-021, SACM Bulletins, Presumptive
Febnnuy 1993, Vol. 2, No.l. and SACM Bulletin Presumptive
Remedies, August 1992. VoU. No. 3.
-------
Finally, while the primary focus of the municipal landfill
manual is on streamlining the RI/FS, Superfund's goal
under S ACM is to accelerate the entire clean-up process.
Other guidance issued under the municipal landfill
presumptive remedy initiative identifies design data that
may be collected during the RI/FS to streamline the
overall response process for these sites (see Publication
No. 9355.3-18FS, Presumptive Remedies: CERCLA
Landfill Caps Data Collection Guide, to be published in
October 1993).
CONTAINMENT AS A PRESUMPTIVE
REMEDY
Section 300.430(a)(iii)(B) of the NCP contains the
expectation that engineering controls, such as
containment, will be used for waste thatposesarelatively
low long-term threator where treatmentisimpracticable.
The preamble to the NCP identifies municipal landfills
as a type of site where treatment of the waste may be
impracticable because of the size and heterogeneity of
the con tents (55 FR 8704). Waste in CERCLA landfills
usuallyispresentin large volumes and isaheterogeneous
mixture of municipal waste frequently co-disposed
with industrial and/or hazardous waste. Because
treatment usually is impracticable, EPA generally
considers containment to be the appropriate response
action, or the "presumptive remedy," for the source
areas of municipal landfill sites.
The presumptive remedy for CERCLA municipal
landfill sites relates primarily to containment of the
landfill mass and collection and/or treatment of landfill
gas. In addition, measures to control landfill leachate,
affected ground water at the perimeter of the landfill,
and/orupgradientground-waterthatiscausingsaturaiion
of the landfill mass may be implemented as part of the
presumptive remedy.
The presumptive remedy does not address exposure
pathways outside the source area (landfill), nor does it
include the long-term ground-water response action.
Additional RI/FS activities, including ariskassessment,
will need to be performed, as appropriate, to address
those exposuie pathways outside the source area. It is
expected that RI/FS activities addressing exposure
paihwaysoutside the source generally will be condiKSed
concurrently with the streamlined RI/FS for the landfill
source presumptive remedy. A response action for
exposure pathways outside the source (if any) may be
selected together with the presumptive remedy (thereby
developing a comprehensive site response), or as an
operable unit separate from the presumptive remedy.
Highlight 1 identifies the componentsof the presumptive
remedy. Response actions selected for individual sites
will include only those components that are necessary.
. based on site-specific conditions.
Highlight 1: Componentsof
the Presumptive Remedy:
Source Containment
Landfill cap;
Source area ground-water control
to contain plume;
Leachate collection and treatment;
Landfill gas collection and
treatment; and/or
Institutionalcontrolsto supplement
engineering controls.
The EPA (or State) site manager will make the initial
decision of whether a particular municipal landfill site
is suitable for the presumptive remedy or whether a
more comprehensive RI/FS is required. Generally, this
determination will dependon whether the site is suitable
for a streamlined risk evaluation, as described on page
4. The community, state, and potentially responsible
parties (PRPs) should be notified that a presumptive
remedy is being considered for the site before worit on
the RI/FS work plan is initiated. The notification may
takethefoimofafactsheet,anotkeinalocalnewspaper,
and/or a public meeting.
Use of the presumptive remedy eliminates the need for
the initial identification and screening of alternatives
during the feasibility study (FS). Section 300.430(e)(l)
of file NCP stales that,"... the lead agency shall include
an alternatives screening step, when needed, (emphasis
added) to select a reasonable number of alternatives for
detailed analysis."
EPA conducted an analysis of potentially available
technologies for municipal landfills and found that
certain technologies are routinely and appropriately
screened out on the basis of effectiveness, feasibility, or
cost(NCP Section 300.430(e)(7)). (See Appendix A to
this directive and "Feasibility Study Analysis for
CERCLA Municipal Landfills," September 1993
available at EPA Headquarters and Regional Offices.)
Based on this analysis, the universe of alternatives thai
will be analyzed in detail may be limited to the
components of the containment remedy identified in
Highlight 1, unless site-specific conditions dictate
otherwise or alternatives are considered that were not
addresssdin the FS analysis. TheFS analysisdocument,
together with this directive, must be included in the
administrative record for each municipal landfill
presumptive remedy site to support elimination of the
initial identification and screening of site-specific
alternatives. Further detailed and comprehensive
-------
supporting materials (e.g., FS reports included in
analysis, technical reports) can be provided by
Headquarters, as needed.
While the universe of alternatives to address the landfill
source will be limited to those components identified in
Highlight 1, potential alternatives that may exist for each
component or combinations of components may be
evaluated in the detailed analysis. For example, one
component of the presumptive remedy is source area
ground-water control. If appropriate, this component
may be accomplished in a number of v/ays. including
pump and treat, slurry walls, etc. These potential
alternatives may then be combined with other components
of the presumptive remedy to develop a range of
containment alternatives suitable for site-specific
conditions. Response alternatives must then be evaluated
in detail against the nine criteria identified in Section
300.430(eXg) of the NCP. The detailed analysis will
identify site-specific ARARs and develop costs on the
basis of the particular size and volume of the landfill.
EARLY ACTION AT MUNICIPAL
LANDFILLS
EPA has identified the presumptive remedy site categories
as good candidates for early action under SACM. At
municipal landfills, the upfront knowledge that the source
area will be contained may facilitate such early actions as
installatwnofalandfillcaporaground-watcrcontainrnent
system. Depending on the circumstances, early actions
may be accomplished using either removal authority
(e.g.. non-time-critical removal actions) or remedial
authority. In some cases, it may be appropriate for an
Engineering Evaluation/Cost Analysis to replace part or
all of the RI/FS if the source control component will be a
non-time-critical removal action. Some factors may affect
whether a specific response action would be better
accomplished as a removal or remedial action including
the size of the action, the associated state cost share, and/
or the scope of O&M. A discussion of these factors is
contained in Early Action and Long-term Action Under
SACM - Interim Guidance, Publication No. 9203.1-051.
December 1992.
SCOPING A STREAMLINED RI/FS
UNDER THE PRESUMPTIVE REMEDY
FRAMEWORK
The goal of an RI/FS is to provide the information
necessary to: (1) adequately characterize the site; (2)
define site dynamics: (3) define risks; and (4) develop the
response action. As discussed in the following sections.
the process for achieving each of these goals can be
streamlined for CERCLA municipal landfill sites because
of the upfront presumption that landfpl contents will be
contained. The strategy for streamlining each of these
areas should be developed early (i.e., during the scoping
phase of the RI/FS).
1. Characterizing the Site
The use of existing data is especially important in
conducting a streamlined RI/FS for municipal landfills.
Characterization of a landfill's contents is not necessary
or appropriate for selecting a response action for these
sitesexcept in limited cases; rather, existingdata are used
to determine whether the containment presumption is
appropriate. Subsequent sampling efforts should focus
on characterizing areas where contaminant migration is
suspected, such as leachate discharge areas or areas
where surface water runoff has caused erosion. It is
important to note that the decision to characterize hot
spots should also be based on existing information, such
as reliable anecdotal information, documentation, and/or
physical evidence (see page 6).
In those limited cases where no information is available
for a site, it may not be advisable to initiate use of the
presumptive remedy until some data are collected. For
example, if there is extensive migration of contaminants
from a site located in an area with several sources, it will
be necessary to have some information about the landfill
source in order to make an association between on-site
and off-sitet»ntamination.
Sources of information of particular interest during
scoping include records of previous ownership, state
files, closure plans, etc.. which may help to determine
types and sources of hazardous materials present In
addition, a site visit is appropriate for several reasons,
including she verification of existing data, the identification
of existing site remediation systems, and to visually
characterize wastes (e.g., leachate seeps). Specific
information to be collected is provided in Sections 2.1
through 2.4 of the municipal landfill manual
2. Denning Site Dynamics
The collected data are used to develop a conceptual site
model, which is the key component of a streamlined
RI/FS. The conceptual site model is an effective tod for
defining the site dynamics, streamlining the risk
evaluation, and developing the response action. Highlight
2 presents a generic conceptual site model for municipal
landfills. The model is developed before any RI field
activities are conducted, and its purpose is to aid in
understanding and describing the site and to present
hypotheses regarding:
The suspected sources and types of
contaminants present;
• Contaminant release and transport
mechanisms;
-------
Highlight 2: Generic Conceptual Site Model
SECONOAMV
COHTAUMAMT
3OUHCZ
• Raieofcomaminantrcleaseand transport
(where possible);
• Affected media;
• Known and potential routes of migration;
and
Known and potential human and
environmental receptors.
After the data are evaluated and a site visit is completed,
the con taminaiuielease and transport mechanisms relevant
to the site should be determined. The key element in
developing the conceptual site model is to identify those
aspects of the model that require more information to
make a decision about response measures. Because
containment of the landfill's contents is the presumed
response action, the conceptual site model will beof most
use in identifying areas beyond the landfill source itself
that will require further study, thereby focusing site
characterization away from the source area and on areas
of potential contaminant migration (e.g., ground water or
contaminated sediments).
3. Defining Risks
The municipal landfill manual states thatastreamlined or
limited baseline risk assessment will be sufficient to
initiate response action on the most obvious problems at
a municipal landfill (e.g.. ground water, leachate, .landfill
contents, and landfill gas). One method for establishing
risk using a streamlined approach is to compare
contaminantcaneentration levels (if available) (ostaodards
that are potential chemical-specific applicabteor relevant
and appropriate requirements (ARARs) for the action.
The manual states thai where established standards for
one or more contaminants in a given medium are clearly
exceeded, remedial action generally is warranted.
It is important to note, however, that based onate-
specific conditions, an active response is not CHSUttEfl r"
ground-water contaminant concentrations exceed
chemical-specific standards but the site risk is within the
Agency's acceptable risk range (10* to 10*). For
example, if it is determined that the release of
'See dtoOSWER Directive 9355.0-30. RoU cftht fl««/i~ Risk
Atsessmaa m Suptrfiiad *m* ,
l991.whichaaailuiifMCLiornon-ieroMCLOfueexcaeaeo.it
response) action generally ii w
-------
contaminants from a particular landfill, is declining, and
concentrations of oneor more ground-water contaminants
are at or barely exceed chemical-specific standards, the
Agency may decide not to implement an active response.
S uch a decision might be based on the understanding that
the landfill is no longer acting as a source of ground-water
contamination, and that the landfill does not present an
unacceptable risk from any other exposure pathway.
A site generally will not be eligible for a streamlined risk
evaluation if ground-water contaminant concentrations
do not clearly exceed chemical-specific standards or the
Agency's accepted level of risk, or other conditions do
not exist that provide a clear justification for action (e.g.,
direct contact with landfill contents resulting from unstable
slopes). Under these circumstances, a quantitative risk
assessment that addresses all exposure pathways will be
necessary to determine whether action is needed.
Ultimately, it is necessary to demonstrate that the final
remedy addresses all pathways and contaminants of
concern, not just those that triggered the remedial action.
As described in the following sections, the conceptual
site model is an effective tool for identifying those
pathways and illustrating that they have been addressed
by the containment remedy.
Streamlined Risk Evaluation Of The Landfill
Source
Experience from the presumptive remedy pilots supports
the usefulness of a streamlined risk evaluation to initiate
an early response action under certain circumstances. As
a matter of policy, for the source area of municipal
landfills, a quantitative risk assessment that considers all
chemicals, their potential additive effects, etc., is not
necessary to establish a basis for action if ground-water
daiaareavailabletodemoristratethatcontaminanisclearly
exceed established standards or if other conditions exist
that provide a clear justification for action.
A quantitative risk assessment also is not necessary to
evaluate whether the containment remedy addresses all
pathways and contaminants of concern associated with
the source. Rather, all potential exposure pathwayscan be
identified ugfflg Kfo6 confifffflU8ill E^ model and compared
to the oath wavs addressed bv the containment presumptive
remedy. Highlights UlusBrates that the contiiinmentremedy
addresses all exposure pathways associated with the
source at municipal landfill sites.
Finally, a quantitative risk assessment is not required to
determine clean-up levels because the type of cap will be
determined by closure ARARs. and ground water that is
extracted asacompooent of the presumptive remedy will
be required to meet discharge limits, or other standards for
its disposal. Calculation of clean-up, levels for ground-
water contamination that has migrated away from the
source will not be accomplished under the presumptive
Highlight 3: Source Contaminant
Exposure Pathways Addressed
by Presumptive Remedy
1. Direct contact with soil and/or
debris prevented by landfill cap;
2. Exposure to contaminated ground
water within the landfill area
prevented by ground-water
control;
3. Exposure to contaminated
leachate prevented by leachate
collection and treatment; and
4. Exposure to landfill gas
addressed by gas collection and
treatment, as appropriate.
remedy, since such contamination will require a
conventional investigation and a risk assessment.
Streamlining the risk assessment of the source area
eliminates the need for sampling and analysis to support
thec^ciilationofcunentorpoientialfutureriskassociated
with direct contact It is important to note that because the
continued effectiveness of the containment remedy
depends on the integrity of the containment system, it is
likely that institutional controls will be necessary to
restrict future activities at a CERCLA municipal landfill
afterconsmiction of thecap and associaied systems. EPA
has thus determined that it is not appropriate or necessary
to estimate the risk associated with future residential use
of the landfill source, as such use would be incompatible
with the need to maintain the integrity of the containment
system. (Long-term waste management areas, such as
municipal landfills, may be appropriate, however, for
recreational or other limited uses on a site-specific basis.)
The availability and efficacy of institutional controls
should be evaluated in the FS. Decision documents
should include measures such as institutional controls to
ensure thecontinuedintegrity of suchcontainmentsysteins
whenever possible.
Areas of Contaminant Migration
Almostevery municipal landfillsitehassomecharacteristic
that may require additional study, such as leachate
discharge toawedand or significant surface water run-off
caused by drainage problems. These migration pathways,
as well as ground-water contamination that has migrated
away from the source, generally will require
diaracterizationandamcre comprehensive risk assessment
to determine whether action is warranted beyond the
source area and, if so, the typeof action that is appropriate.
While future residential use of the landfill source area
itself is not considered appropriate, the land adjacent to
-------
landfills is frequently used for residential purposes.
Therefore, based on site-specific circumstances, it may be
appropriate to consider future residential use for ground
water and other exposure pathways when assessing risk
from areas of contaminant migration.
4. Developing the Response Action
As a first step in developing containment alternatives,
response action objectives should be developed on the
basis of the pathways identified for action in the
conceptual site model. Typically, the primary response
action objectives for municipal landfill sites include:
Presumptive Remedy
• Preventing direct contact with landfill
contents;
Minimizing infiltration and resulting
contaminant leaching to ground water;
• Controlling surface water runoff and
erosion;
• Collecting and treating contaminated
ground water and leachate to contain
the contaminant plume and prevent
further migration from source area;
and
• • Controlling and treating landfill gas.
Non-Presumptive Remedy
• Remediating ground water;
Remediating contaminated surface
water and sediments; and
• Remediating contaminated wetland
areas.
As discussed in Section 3. "Defining Risks," the
containment presumptive remedy accomplishes all but
the last three of these objectives by addressing all
pathways associated with the source. Therefore, the
focus of the Rl/FS can be shifted to characterizing the
media addressed in the last three objectives
(contaminated ground water, surface water and
sediments, and wetland areas) and on collecting data to
support design of the containment remedy.
Treatment of Hot Spots
The decision to characterize and/or treat hot spots is a
site-specific judgement that should be based on the
consideration of a standard set of factors. Highlight 4
lists questions that should be answered before making
the decision to characterize and/or treat hot spots. The
overriding question is whether the combination of the
waste's physical and chemical characteristics and volume
is such that the integrity of the new containment system
will be threatened if the waste is left in place. This
question should be answered on the basis of what is
known abouta site (e.g.. from operating records or other
reliable information). An answer in the affirmative to all
of the questions listed in Highliglu4 would indicate that
it is likely that the integrity of the containment system
would be threatened, or that excavation and treatmentof
hot spots would be practicable, and that a significant
reduction in risk at the site would occur as a result of
treating hot spots. EPA expects that few CERCLA
municipal landfills will fall into this category; rather,
based on the Agency's experience, the majority of sites
are expected to be suitable for containment only, based
on the heterogeneity of the waste, the lack of reliable
information concerning disposal history, and the
problems associated with excavating through refuse.
The volume of industrial and/or hazardous waste co-
disposed with municipal waste at CERCLA municipal
landfills varies from site to site, as does the amount of
information available concerning disposal history. It is
impossible to fully characterize, excavate, and/or treat
the source area of municipal landfills, so uncertainty
about the landfill contents is expected. Uncertainty by
itself does not call into question the containment
approach. However, containment remedies must be
designed to take into account the possibility that hot
spots are present in addition to those that have been
identified and characterized. The presumptive remedy
must be relied upon to contain landfill contents and
prevent migration of contaminants. Thisisaccomplished
by a combination of measures, such as a landfill cap
combined with a leachate collection system. Monitoring
will further ensure the continued effectiveness of the
remedy.
The following examples illustrate site-specific decision
making and show how these factors affect the decision
whether to characterize and/or treat hot spots.
Examples of Site-Specific Decision Making
Concerning liot Spot Characterization/
Treatment . . .
Site A
There is anecdotal information that approximately 200
druifs of hazardous waste were disposed of at this 70-
acre former municipal landfill, but their location and
contents are unknown. The remedy includes a landfill cap
and ground-water and landfill gas treatment.
A search for and characterization of hot spots is not
supported at Site A based on the questions listed in
-------
Highlight 4: Characterization
of Hot Spots
If all of the following questions can be
answered in the affirmative, it is likely
that characterization and/or treatment
of hot spots is warranted:
1. Does evidence exist to indicate
the presence and approximate
location of waste?
2. Is the hot spot known to be
principal threat waste?*
3. Is the waste in a discrete,
accessible part of the landfill?
4. Is the hot spot known to be large
enough that its remediation will
reduce the threat posed by the
overall site but small enough that
it is reasonable to consider
removal (e.g., 100.000 cubic
yards or less)?
'See A Guide to Principal Throat and Low
Level Threat Wastes. November 1991.
Superfund Publication No. 9380.3-O6FS.
Highlight 4: (1) no reliable information exists to indicate
the location of the waste; (2) the determination of whether
the waste is principal threat waste cannot be made since
the physical/chemical characteristics of the wastes are
unknown; (3) since the location of the waste is unknown.
the determination of whether the waste is in a discrete
accessible location cannot be made; (4) in this case, the
presenceof200 drums ina70-acrelandfill is not considered
to significantly affect the threat posed by the overall site.
Rather, the containment system will include measures to
ensure its cantinuedeffectiveness(e.g.. monitoring and/or
leachate collection) given the uncertainty associated with
the landfill contents and suspected drums.
SiteB
Approximately 35,000 drums, many containing hazardous
wastes, were disposed of in two drum disposal units at this
privately owned 80-acre inactive landfill, which was
licensed to receive general refuse. The site is divided into
two operable units. The remedy for Operable Unit 1 (OU
1) is incineration of drummed wastes in the two drum
disposal units. The remedy for OU 2 consists of treatment
of contaminated ground water and leachate and
containment of treatment residuals (from OU 1) and
remaining landfill contents, including passive gas
collection and flaring.
Treatment of landfill contents is supported at Site, B
because all of thequestions in Highlight4can be answered
in the affirmative: (1) existing evidence from previous
investigations and sampling conducted by the state (prior
to the RI) indicated the presence and approximate location
of wastes; (2) the wastes were considered principal threat
wastes because they were liquids and (based on sampling)
were believed to contain contaminants of concern; (3) the
waste is located in discrete accessible parts of the landfill;
and (4) the waste volume is large enough that its
remediation will significantly reduce the threat posed
by the overall site.
CLOSURE REQUIREMENTS
Subtitle D
In the absence of Federal Subtitle D closure regulations.
State Subtitle D closure requirements generally have
govemedCERCLA response actions atmunicipal landfills
as applicable or relevant and appropriate requirements
(ARARs). New Federal Subtitle D closure and post-
closure care regulations will be in effect on October 9,
1993 (56 FR 50978 and 40 CFR 258).* State closure
requirements that are ARARs and that are more stringent
than the Federal requirements must be attained or waived.
The new Federal regulations contain (equiremeamelated
to construction and maintenance of the final cover, and
leachate collection, ground-water monitoring, and gas
monitoring systems. The final cover regulations will be
applicable requirements for landfills that received
household wasteafterOctober9,1991. EPA expects that
the final cover requirements will be applicable to few. if
any, CERCLA municipal landfills, since the receipt of
household wastes ceased at most CERCLA landfills
beforeOctober 1991. Rather, the substantive requirements
of the new Subtitle D regulations generally will be
considered relevant and appropriate requirements for
CERCLAresponseaokxisthatoocurafkrtheeffectivedate.
Subtitle C
RCRASubtitleC closure requirements may Inapplicable
or relevant and appropriate in certain circumstances.
RCRA Subtitle C is applicable if the landfill received
waste that is a listed or characteristic waste under
RCRA. and:
1. TnewastewasdisposedofafterNovemberl9,1980
(effective date of RCRA), or
'An extouion of the effective date has been proposed but mx
finalized at this lime.
-------
2. The new response action constitutes disposal under
RCRA (i.e.. disposal back into the original landFdl).'
The decision about whether a Subtitle C closure
requirement is relevant and appropriate is based on a
variety of factors, including the nature of the waste and its
hazardous properties, the date on which il was disposed,
and the nature of the requirement itself. For more
information on RCRA Subtitle C closure requirements.
see RCRA ARARs: Focus on Closure Requirements,
Directive No. 9234.2-04FS. October 1989.
'Note thai disposal of only until qutntity hazardous wane and
household hazardous waste does not make Subtitle C applicable.
Notice:
The policies set out in this document are intended solely as guidance to the UJS. J07'1?"^"?!^
Protection Agency (EPA) personnel; they are not final EPA actions and do not ™^*™*™e™™Hto
Thesepoliciesarenot intended, norcan they be relied upon, to create any n9Wse"forceabte5MlS
in litigation with the United States. EPA officials may decide to follow the ^'J^PJJJJJIJS?
document, or to act at variance with the guidance, based on an analysis of specific site circumstances.
EPA also reserves the right to change the guidance at any time without public notice.
-------
APPENDIX A
TECHNICAL BASIS FOR PRESUMPTIVE REMEDIES
This Appendix summarizes the analysis that EPA conducted of feas.b.lrty study (FS) and Record
of Decision (ROD) data from CERCLA municipal landfill sites which led to the establishment of
containment as the presumptive remedy for these sites. The objective of the study was to identrfy those
technologies that are consistently included in the remedies selected, those that are consistently
screened out, and to identify the basis for their elimination. Results of this analysis support the decision
to eliminate the initial technology identification and screening steps on a site-specific basis for this site
type. The technical review found that certain technologies are appropriately screened out based on
effectiveness, implementability, or excessive costs.
The methodology for this analysis entailed reviewing the technology identification and screening
components of the remedy selection process for a representative sample of municipal landfill sites. The
number of times each technology was either screened out or selected in each remedy was compiled.
A detailed discussion of the methodology used is provided below.
METHODOLOGY
Identification of Sites (or Feasibility Study Analysis
Of the 230 municipal landfill sites on the NPL, 149 sites have had a remedy selected for at least
one operable unit. Of the 149 sites. 30 were selected for this study on a random basis, or slightly greater
than 20 percent. The sites range in size from 8.5 acres to over 200 acres and are located primanty in
Regions 1,2,3. and 5. This geographical distribution approximates the distribution of municipal landfills
on'the.NPL.
Teehnotoav Screenina and Remedial Alternative Analysis
The FS analysis involved a review of the technology identification and screening phase,
including any pre-screening steps, followed by a review of the detailed analysis and comparative
analysis phases. I nformation derived from each review was documented on site-specific data collection
forms, which are available for evaluation as part of the Administrative Record for this presumptive
remedy directive. The review focused on the landfill source contamination only; ground-water
technologies and alternatives were not included in the analysis.
For the screening phase, the full range of technologies considered was listed on the data
collection forms, along with the key reasons given for eliminating technologies from further consider-
ation. These reasons were categorized according to the screening criteria: cost, effectiveness, or
implementability. The frequency with which specific reasons were given for eliminating a technology
from further consideration was then tallied and compiled into a screening phase summary table.
For the detailed analysis and comparative analysis, information on the relative performance of
each technology/alternative with respect to the seven NCR criteria was documented on the site-specific
data collection forms. The advantages and disadvantages associated with each clean-up option were
highlighted. In some cases, a technology was combined with one or more technologies into one or more
alternatives. The disadvantages of a technology/alternative were then compiled into a detailed
analysis/comparative analysis summary table, under the assumption that these disadvantages
contributed to non-selection. All summary tables are available for review as part of the Administrative
Record.
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APPENDIX A
TECHNICAL BASIS FOR PRESUMPTIVE REMEDIES (continued)
RESULTS
The information from the technology screening and «n""J8r
in Table 1 . It demonstrates that containment (the presumptive ^^
of the selected remedy at all thirty of the sites analyzed. No other ^
consistent* selectees a remedy or retained for consideration in £, r
eight of the thirty sites, there were circumstances where technotog.es i were !
remedy to address a site-specific concern, such as pnnapal threat wastes.
included in the column entitled "Tech. Not Primary Component of Alternate' i
incineration at two sites, waste removal and off-site disposal at two sites. so,l vapor extracts at two
sites, and bioredamation at one site.
Leachate collection and gas collection systems were also tracked as
analysis and comparison of remedial alternatives. These types of **"%
considered as remediation technologies during the screening phases. At fifteen
collection was selected as part of the overall containment remedy. At seventeen srtes. gas collection
systems were selected as part of the overall containment remedy.
This analysis supports the decision to eliminate the initial technology identification and
screening step for municipal landfill sites. On a site-specific basis, consideration of remed.aton
technologies may be retained as needed. . _____ __
« This column title is used for record-keeping purposes only and is not meant to imply that these treatment
technologies are not considered important components of the selected remedies.
10
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TABLE !• SUMMARY OF SCREENING AND DETAILED ANALYSIS FOR LANDFILLS 1
TECHNOLOGY 2
8 ROOs WHERE CRCERION CONTRIBUTED TO NON-SELECTION
X
Multi-layer
Cap
28
25
18
Clay
Cap
16
Asphalt
Cap
17
17
14
Conertte
Cap
17
17
14
Soil
Cover
16
Synthetic
Cap
13
10
10
Chemical
Seal
•' 6
Slurry
Wall
22
14
Gnut
Curtain
18
18
15
Sheet
Piling
17
16
13
Gnut
Injecfon
Block
Displacement
Bottom
Sealing
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TABLE 1 • SUMMARY OF SCREENING AND DETAILED ANALYSIS FOR LANDFILLS (Continued)
i RODs WHERE CWERICH CONTRIBUTED TO NOH-SELECTICN
-------
TABLE 1 • SUMMARY OF SCREENING AND DETAILED ANALYSIS FOR LANDFILLS (Continued)
I RODs WHERE CRITERION CONTRIBUTED TO NON-SELECTION
itwrmal
3wtruction
'unspocHwd)
LowTtmpmttn
Thwmal Dtsw el
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TABLE 1 • SUMMARY OF SCREENING AND DETAILED ANALYSIS FOR LANDFILLS (Continued)
TECHNOLOGY '
IfStWlwt
OtwfenCenttltuUd
I RODs WHERE CRIIRICH CONTRIBUTED TO NOK-SELECTICH
Sol
Wuhtng
12
Soil Vapor
Enaction (SVE)
14
11
Rxation
Stabilization/
Solidification
Aeration
20
19
13
ThisituoVwaiconduclBdonaOROOnndMrcofWipondingFS*.
!£?.!!
ntaranc* supportng doeunwntafcn (L«., Stan ooneurwne* tos«r an(Jft«(x»i«iv«ntMiunmjy).
-------
United States
Environmental Protection
Agency
Washington. D.C. 20460
Official Business
Penalty for Private Use
$300
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EPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Directive No. 9355.0-661
EPA 540/F-96/017
PB 96-963313
January 1997
Landfill Presumptive Remedy
Saves Time and Cost
Office of Emergency and Remedial Response (5202G)
Intermittent Bulletin
Volume 1 Number 1
Since Superfund's inception in 1980. the removal and remedial programs have found that certain categories of sites have similar
characteristics, such as types of contaminants present, past industrial use, or environmental media affected. Based on a wealth of
information acquired from evaluating and cleaning up these sites, Superfund undertook the presumptive remedy initiative to develop
remedies that are appropriate for specific site types and/or contaminants. One site category for which EPA developed a presumptive remedy
is municipal landfills. This bulletin summarizes the results of implementing the containment presumptive remedy at three CERCLA
municipal landfill sites. At each of the sites, both time and costs were saved in conducting the RI/FS. When compared to similar "control"
sites, EPA estimates time savings ranging from 36 to 56 percent, and cost savings up to 60 percent In addition to demonstrating significant
time and cost savings, the pilots also indicate that municipal landfill sites are good candidate sites for implementing the presumptive remedy
as an early action, such as a non-time-critical removal. The combination of this presumptive remedy with an early action resulted in
significant savings at one pilot site.
Introduction
EPA expects that the use of presumptive remedies will streamline
removal actions, site studies, and cleanup actions while
improving consistency, reducing costs, and increasing the speed
with which hazardous waste sites are remediated. EPA has
developed several presumptive remedies to date; a list of
presumptive remedy directives is provided at the end of this
document. The results of implementing the containment
presumptive remedy at three CERCLA municipal landfill sites
are discussed in this bulletin.
The Containment Presumptive Remedy
EPA established containment as the presumptive remedy for
municipal landfills in September 1993. The containment
presumptive remedy includes the following components, as
appropriate on a site-specific basis:
• Landfill cap;
• Source area ground-water control to contain plume;
• Leachate collection and treatment;
• Landfill gas collection and treatment;
• Institutional controls to supplement engineering controls.
The presumptive remedy does not address exposure pathways
outside the source area (landfill), nor does it include long-term
ground-water response actions.
The Pilot Sites
Prior to establishing the presumptive remedy, EPA initiated a
pilot project at three sites to assess the effectiveness of the
containment remedy in streamlining the remedial
investigation/feasibility study (RI/FS) process for municipal
landfills. The pilots implemented the streamlining principles
outlined in the document, "Conducting Remedial
Investigations/Feasibility Studies for CERCLA Municipal
Landfill Sites," February 1991, Directive No. EPA/540/P-91001
(hereafter referred to as the "1991 MLF RI/FS guidance"). This
1991 MLF RI/FS guidance provides the implementation
framework of the containment presumptive remedy.
EPA found the containment remedy to be a very effective tool for
streamlining the RI/FS at municipal landfills. This bulletin
describes the pilot sites, the ways in which each RI/FS was
streamlined, and the time and cost savings realized at each of the
sites. See Attachment A at the end of this bulletin for brief site
summaries.
Who Can Use The Presumptive Remedy?
i <5r °f a municipal landfi11 site-il is Iike|y mat *« Presumptive remedy can help you save time and money on
the RI/FS at your site. Although the presumptive remedy is most beneficial when incorporated at the scoping stage of the RI/FS
if your sue has progressed beyond that point, you may still be able to streamline your site characterization samolinE sffateev
baseline risk assessment, and/or feasibility study. 5J>
-------
EPA piloted the containment remedy at the following municipal
landfills beginning in the Spring of 1992:
• Albion-Shcndan Township Landfill. Michigan
» Lexington County Landfill. South Carolina
• BFI/Rockingham Landfill. Vermont
These sites were selected as pilots because they were in the
scoping phase of the RI/FS at the time. The biggest savings in
time and cost can be realized if streamlining is incorporated at
the very beginning of the scoping phase of the RI/FS. All of
these sites now have signed Records of Decision (RODs). with
containment selected as pan of the remedy at each of the sites.
EPA evaluated the impact of the containment remedy as a
streamlining tool at the three pilot sites by estimating time and
cost savings. The sites were evaluated in a paired analysis,
comparing the pilot sites to the three "control" sites listed in
Highlight 1. Remedy selection at the control sites was based on
the results of conventional RI/FSs.
The factors considered in selecting the "control" sites included
(listed in order of priority): (1) the state in which the landfill is
located since State closure requirements often affect aspects of
remedy selection; (2) the lead for the site (e.g.. Fund-lead); and
(3) the size of the landfill (in acres). Summary information on
the pilot and control sites is provided in Highlight 1.
Highlight 1
Pilot/Control Site Characteristics
PILOT STTES
Name
Albion-
Sheridan
BH
Lexington
Co.
State
M
VT
SO
Lead
F '
PRP
PRP
Size
30
19
70
CXJRHESPC*ONG CONTROL SITES
Nanne
West
ML
Parker
Cedar-
tcwi
LF
Stale
M
VT
GA
Lead
F
PRP
PRP
Size
87
19
6.8
,
Pilot Results
Two areas of the RI/FS process presented the greatest
opportunity for streamlining at the pilot sites: 1) a phased
approach to site characterization, and 2) streamlining the risk
assessment.
Phased Approach to Site Characterization
The containment presumptive remedy emphasizes the use of
existing data to the degree possible, and discourages
characterization of landfill contents since it is presumed that the
landfill will be contained, unless information is available
indicating the need to investigate and potentially remove or treat
hot spots. In keeping with these principles, a phased approach
to sampling is recommended.
The phased approach to site characterization is a site-specific
strategy that frames the data collection effort within the context
of determining whether a risk is present at a site rather than
characterizing the nature and extent of all contamination in a
landfill.1 A site-specific determination is made as to the
environmental medium most likely to present a risk based upon
any existing data available, and 'sampling of that pathway is
conducted first.
At many landfill sites, ground-water contamination is likely to
present a significant risk, and thus trigger the need for action.2
At the pilot sites, ground water was the first medium sampled,
and at each of the pilot sites, ground-water contamination
supported the. need for a response action. In two cases, soil
sampling of the landfill source area was never conducted;
sampling was limited to determining risk from the ground water.
At one site, the State conducted additional sampling of the
landfill area.
If ground-water data had not clearly demonstrated a risk at the
pilot sites, additional sampling would have been conducted (in
sequence) to determine whether a risk was present from other
media or exposure pathways, such as contaminated soil and/or
landfill gas. At the pilot sites, additional sampling was not
necessary to determine risk, and since containment of the landfill
was presumed, sampling and analysis was not required for the
purpose of site characterization.
Streamlined Risk Assessment
For many landfill sites, it will be possible to streamline the risk
assessment portion of the RI/FS. This is possible because the
containment remedy addresses all migration pathways presented
by the landfill source. The basis of the streamlined risk
assessment process to be employed at MLFs is the conceptual
site model (discussed in Section 2.5 of the 1991 RI/FS MLF
guidance), which is used to identify all exposure pathways
associated with the landfill source (i.e., direct contact with soil,
exposure to contaminated ground water, contaminated
'This phased approach applies to the landfill source only.
Contamination that has migrated away from the landfill source
must be characterized, and the associated risk estimated.
2See OSWER Directive 9355.0-30. "Role of the Baseline Risk
Assessment in Superfund Remedy Selection Decisions," April
22, 1991. which states that if MCLs or non-zero MCLGs are
exceeded, [a response] action generally is warranted.
-------
leachate. and/or landfill gas). The exposure pathways are then
compared to those addressed by the containment remedy, as
follows: .
• direct contact with soil and/or debris prevented by landfill
cap;
• exposure to contaminated ground water prevented by
ground-water control:
• exposure to contaminated leachate prevented by leachate
collection and treatment: and
• exposure to landfill gas addressed by gas collection and
treatment, as appropriate.
This comparison reveals that the containment remedy addresses
all pathways associated with the landfill source. The phased
approach can be implemented at landfill sites using the
conceptual site model because it demonstrates that all exposure
pathways are addressed by the containment remedy, and field
sampling is therefore not required to characterize the nature and
extent of contamination once it has been demonstrated that the
site presents a risk and warrants action.
A streamlined risk evaluation was successfully conducted at the
three pilot sites, with contaminated ground water presenting the
justification for a response action. Sampling, analysis, and a
conventional risk assessment were required to characterize
contamination, if any. that had migrated away from the source
areas.
Quantitative Results
As illustrated in Highlight 2. the Rl/FS durations for the pilot
sites ranged from 23 to 32 months, compared to 44 to 72 months
for the control sites. The average pilot RI/FS duration was 28
months, as compared to the national average of 51 months. The
RI/FS durations for the pilot sites represent a time savings
ranging from 16 to 40 months when compared to the control
sites, and 23 months when compared to the national average.
These results translate into an estimated time savings ranging
frpm 36-56 percent when comparing the pilots to the control
sites, and an estimated 45 percent when comparing the average
pilot duration to the national average.
The figures for the BFI/Rockingham site include completion of
an Engineering Evaluation/Cost Analysis (EE/CA) to support
implementation of source control (i.e.. cap, leachate and gas
collection) as a non-lime-critical removal action. The EE/CA was
completed in 12 months, which is a subset of the 23 months
indicated in Highlight 2. The 23 months was the time required to
complete the RI/FS for the entire site, including ground-water
contamination.
The pilot results for the BFI/Rockingham site are particularly
noteworthy because the source control action was initiated just
12 months after the RI/FS start, and construction of the cap was
completed in July 1995, just three years after the RI/FS start.
A savings in time was also realized as a result of the streamlined
risk evaluations conducted at the pilot sites, as illustrated in
Highlight 3. The time required to complete the risk assessments
at the pilot sites ranged from 7 to 10 months, as compared to 9 to
22 months for the controls, which represents a savings ranging
from 17 to 68 percent when compared to the control sites.
Highlight 2
RI/FS Durations (Months) for Pilot/Control Site
and National Averages
60
23
51
Mtuv MM Lnlnj. CM»
SMttri ML fcnCtt KM!
IF
Highlights
Risk Assessment Durations (Months) for
Pilot/Control Sites
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Cost savings were estimated in one of two ways for the pilot
sites. The RI/FS costs for Albion-Sheridan Landfill and
Lexington County were compared to the national average RI/FS
cost of SI million, resulting in an estimated 10 percent and 1
percent savings, respectively, for those sites. The cost savings
estimate for the BFI/Rockingham site was developed by the PRP,
and was based upon a comparison with their costs for RI/FSs
conducted at other similar sites. A savings of 60 percent was
estimated for the RI/FS. which included the source area and areas
of migration, and an engineering evaluation/cost analysis
(EE/CA) to support the non-time-critical removal action on the
landfill cap.
Conclusion
EPA found that the containment presumptive remedy resulted in
a savings of time and costs at each of the pilot sites. The savings
were the result of implementing a phased approach to site
characterization and streamlining the risk assessment, both of
which were possible because the landfill contents were
contained.
The savings in time and costs were most significant at the
BFI/Rockingham site, where the cap was completed three years
after initiation of the RI/FS. and an estimated S3 million was
saved. This significant savings was the result of combining the
containment presumptive remedy with an early action
accomplished as a non-time-critical removal action. Based on
these results, municipal landfill sites appear to be well suited to
the combined application of these streamlining and acceleration
tools.
Next Steps
Since establishment of the presumptive remedy. EPA has tracked
implementation at 'two additional landfill sites (demonstration
sites): (1) Bennington Landfill. Vermont, and (2) Toman
Municipal Landfill, Wisconsin. EPA will summarize findings
from the demonstration sites upon signature of their respective
Records of Decision (RODs).
Presumptive Remedy Directives
To date, EPA has issued the following presumptive remedy
directives:
(1) "Presumptive Remedies: Policy and Procedures,"
September 1993, Directive No. 9355.0-47FS;
(2) "Conducting Remedial Investigations/Feasibilities
Studies for CERCLA Municipal Landfill Sites,"
EPA/540/P-91/001, February 1991.
(3) "Presumptive Remedy for CERCLA Municipal Landfill
Sites," September 1993, Directive No. 9355.0-49FS;
(4) "CERCLA Landfill Caps RI/FS Data Collection Guide,"
August 1995, Directive No. 9355.3-18FS;
(5) "Site Characterization and Technology Selection for
Volatile Organic Compounds in Soil/Sludge,"
September 1993, Directive No 9355.4-048FS;
(6) "Presumptive Remedies for Soils, Sediments, and
Sludges at Wood Treater Sites," December 1995,
Directive No. 9200.5-162.
(7) "Presumptive Response Strategy and Ex-Situ Treatment
Technologies for Contaminated Ground Water at
CERCLA Sites," EPA/540/R-96/023, October 1996.
In addition, presumptive remedies directives for the following
types of sites or contaminants arc forthcoming:
(1) PCBs
(2) Manufactured gas plants
(3) Grain storage sites
(4) Metals in soils (in cooperation with the U.S. Department
of Energy).
Additional Information
For additional information on the pilot sites or the presumptive
remedy for municipal landfills, please call Andrea McLaughlin,
Office of Emergency and Remedial Response, 703-603-8793.
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Attachment A: Pilot Case Studies
Albion-Sheridan Landfill
Anecdotal evidence indicated that some quantity of
industrial wastes were disposed of at the 30-acre Albion-
Sheridan Landfill, but the location, volume and identity
of wastes were unknown. No data were available for the
site at the beginning of the RI/FS. EPA implemented the
streamlining principles of the 1991 MLF RI/FS guidance,
and scoped a phased approach to characterization of the
Albion-Sheridan site with the goal of implementing the
containment remedy. The draft work plan was revised to
incorporate the phased investigation, focusing first on
ground-water contamination to establish whether there
was a basis for a response action.
Ground-water contamination did support the need for
action at the site, so it was not necessary to quantify
additional exposure pathways for this purpose. The
remainder of the risk assessment was streamlined by
using a conceptual site model to demonstrate that the
other potential pathways of concern (e.g. direct contact)
would be addressed by the components of the
presumptive remedy (e.g. landfill cap).
EPA conducted a geophysical survey of the site to
identify potential drum storage areas. Based on the
results of the geophysics. EPA concluded that while there
were anomalies in the results, there were no-areas that
appeared to consist of large numbers of drummed waste,
thereby warranting further investigation. Because the
State had remaining concerns with EPA's approach to hot
spots, the State conducted its own geophysical survey and
dug test pits at 12 locations. At one location
approximately 300-400 drums were uncovered, and EPA
reiterated its agreement to send any drums of hazardous
waste off-site for disposal. Of the 300-400 drums, the
number containing hazardous waste is unknown at this
time.
Lexington County Landfill
Ground-water data were available for this 70-acre landfill
prior to initiation of the RI. which indicated exceedences
of MCLs. and therefore a basis for a response action.
The strategy for the Lexington County Landfill RI was
similar to the Albion-Sheridan Landfill, in that a phased
approach was implemented. Sampling focused on further
characterization of ground-water contamination, and the
risk assessment was streamlined, focusing also on the
ground-water pathway. Planned soil sampling and
analysis to estimate direct contact threats was eliminated,
and it was demonstrated (using a conceptual site model)
that other potential pathways of concern would be
addressed by components of the presumptive remedy.
A planned drum search of the 70-acre landfill was
eliminated based on the guidelines for hot spot
characterization contained in the 1991 MLF RI/FS
guidance. At Lexington County Landfill, as at Albion
Sheridan Landfill, it is likely that some industrial waste
was disposed of at the site, but the location, quantity and
identity of the wastes were unknown. Because there was
no evidence to guide such a search, EPA decided that the
best approach was to contain the landfill, accounting for
uncertainties in the nature of the wastes during the design.
The selected remedy includes consolidation and capping
of the waste areas, landfill gas collection and venting;
extraction of contaminated groundwaier/leachate with
discharge to POTW; additional sampling of surface water
and sediment to characterize any off-site contamination;
and monitoring of ground water, surface water, sediment
and landfill gas. Additionally, to address a plume, a
ground-water pump and treat remedy was put in place.
BFI/Rockingham
. Extensive ground-water data were available for this site
at the initiation of the RI, and the first step in
implementation of the presumptive remedy was to
evaluate the potential for using the data. The data were
found to be useable to establish an initial basis for action,,
which allowed streamlining of the risk assessment and RI.
Only confirmadonal ground-water sampling was
conducted during the RI; characterization of the landfill
surface soil and debris mass did not occur. Geotechnical
information regarding settlement, cover quality, and
stability was also collected. The knowledge that .
containment was the likely remedy allowed the RI to
become primarily a design-related investigation. In
addition, based on historical information, hot spots were
not of concern at this site.
Levels of volatile organic compounds (VOCs) and certain
metals clearly indicated that a ground-water risk was
present. The existence of ground-water risk confirmed
that a "No Action" decision was unlikely, and that a
landfill cap would be a component of the source control
action. The risk assessment was streamlined by
quantifying the ground-water risk and qualitatively
discussing the other pathways that would be addressed by
the source control action. All pathways outside the
landfill, which included off-site ground water and off-site
soils, were fully quantified. An early action was
conducted as a non-time-critical removal at this site in
order to begin construction of the landfill cap. The
combination of the presumptive remedy with the early
action resulted in a significant time savings in the remedy
selection and construction processes.
-------
-------
United States
Environmental Protection
Agency
Off ice of
Solid Waste and
Emergency Response
Directive No.9355.0-67FS
EPA/540/F-96/020
PB96-963314
December 1996
Application of the CERCLA
Municipal Landfill Presumptive
Remedy to Military Landfills
Federal Facilities Restoration and Reuse Office
Mail Code 5101 *
Quick Reference Fact Sheet
Presumptive remedies are preferred technologies for common categories of sites based on historical patterns of
remedy selection and the U.S. Environmental Protection Agency's (EPA's) scientific and engineering evaluation of
performance data on technology implementation. By streamlining site investigation and accelerating the remedy
selection process, presumptive remedies are expected to ensure the consistent selection of remedial actions and reduce
the cost and time required to clean up similar sites. Presumptive remedies are expected to be used at all appropriate
sites. Site-specific circumstances dictate whether a presumptive remedy is appropriate at a given site.
EPA established source containment as the presumptive remedy for municipal landfill sites regulated under the
Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) in September of 1993 (see the
directive Presumptive Remedy for CERCLA Municipal Landfill Sites). The municipal landfill presumptive remedy
should also be applied to all appropriate military landfills. This directive highlights a step-by-step approach to
determining when a specific military landfill is an appropriate site for application of the containment presumptive
remedy. It identifies the characteristics of municipal landfills mat are relevant to the applicability of the presumptive
remedy, addresses characteristics specific to military landfills, outlines an approach to determining whether the
presumptive remedy applies to a given military landfill, and dispusses administrative record documentation
requirements.
PURPOSE
This directive provides guidance on applying the con-
tainment presumptive remedy to military landfills.
Specifically, this guidance:
• Describes the relevant characteristics of munici-
pal landfills for applicability of the presumptive
remedy;
Presents the characteristics specific to military
installations that affect application of the presump-
tive remedy;
• Provides a decision framework to determine appli-
cability of the presumptive remedy to military
landfills; and
• Provides relevant contacts/specialists in military
wastes, case histories, administrative record docu-
mentation requirements, and references.
BACKGROUND
Municipal landfills are those facilities in which a
combination of household, commercial and, to a lesser
extent, industrial wastes have been co-disposed. The
presumptive remedy for municipal landfills - source
containment — is described in detail in the directive
Presumptive Remedy for CERCLA Municipal Landfill
Sites. Highlight 1 outlines the components of the con-
tainment presumptive remedy. Highlight 2 lists the
characteristics of municipal landfills that are compatible
with the presumptive remedy of containment.
Highlight 1
Components of the Containment
Presumptive Remedy
Landfill cap
Source area groundwater control to
contain plume
Leachate collection and treatment
Landfill gas collection and treatment
Institutional controls to supplement
engineering controls
-------
Highlight 2
Appropriate Municipal Landfill
Characteristics for Applicability
of the Presumptive Remedy
Risks are low-level, except for "hot spots"
Treatment of wastes is usually impractical due
to the volume and heterogeneity of waste
Waste types include household, commercial,
nonhazardous sludge, and industrial solid
wastes
Lesser quantities of hazardous wastes are
present as compared to municipal wastes
Land application units, surface impoundments,
injection wells, and waste piles are not included
The presumptive remedy process involves streamlining
of the remedial investigation/feasibility study (RI/FS)
or, for non-time-critical removals, an Engineering
Evaluation/Cost Analysis (EE/CA) by:
• Relying on existing data to the extent possible rather
than characterizing landfill contents (limited or no
landfill source investigation unless there is informa-
tion indicating a need to investigate hot spots);
• Conducting a streamlined risk assessment; and
• Developing a focused feasibility study that analyzes
only alternatives consisting of appropriate compo-
nents of the presumptive remedy and, as required
by the National Contingency Plan, the no action
alternative.
Several directives, including Presumptive Remedy for
CERCLA Municipal Landfill Sites, Conducting Remedial
Investigations/Feasibility Studies for CERCLA Munici-
pal Landfill Sites, and Streamlining the RI/FS for
CERCLA Municipal Landfill Sites, provide a complete
discussion of these streamlining principles.
USE OF THilS GUIDANCE
EPA anticipates that the containment presumptive
remedy will be applicable to a significant number of
landfills found at military facilities. Although waste
types may differ between municipal and military land-
fills, these differences do not preclude use of source
containment as the primary remedy at appropriate
military landfills.
Additionally, EPA continues to seek greater consistency
among cleanup programs, especially in the process of
selecting response actions for sites regulated under
CERCLA and corrective measures for facilities regu-
lated under the Resource Conservation and Recovery
Act (RCRA). In general, even though the Agency's
presumptive remedy guidances were developed for
CERCLA sites, they should also be used at RCRA
Corrective Action sites to focus RCRA Facility Investi-
gations, simplify evaluation of remedial alternatives in
the Corrective Measures Study, and influence remedy
selection in the Statement of Basis. For more infor-
mation, refer to the RCRA Corrective Action Plan,
the proposed Subpart S regulations, and the RCRA
Corrective Action Advance Notice of Proposed Rule-
making.
The size of the landfill and the presence, proportion,
distribution, and nature of wastes are fundamental to the
application of the containment presumptive remedy to
military landfills.
An examination of 31 Records of Decisions (RODs) that
document the remedial decisions for 51 landfills at
military installations revealed that no action was chosen
for 10 landfills and remedial actions were chosen at 41
landfills (see Appendix). Of these 41 landfills, contain-
ment was selected at 23 (56 percent). For the remaining
18 landfills where other remedies were selected, institu-
tional controls only were selected at three landfills,
excavation and on-site consolidation were selected at
four landfills, and excavation and off-site disposal were
selected for 11 landfills.
The military landfills examined in the 51 RODs men-
tioned above ranged in size from 100 square feet to 150
acres and contained a wide variety of waste types. Of
the 41 landfills for which remedial actions were chosen,
14 (34 percent) were one acre or less in size; containment
was not selected for any of these landfills. Containment
was chosen at 23 (85 percent) of the 27 landfills that
were greater than one acre in size. This information
suggests that the size of the landfill area is an important
factor in determining the use of source containment at
military landfills.
The wastes most frequently deposited at these military
landfills were municipal-type wastes: household, com-
mercial (e.g., hospital wastes, grease, construction
debris), and industrial (e.g., process wastes, solvents,
paints) wastes. Containment was the remedy selected at
the majority of these sites. Military-specific wastes (e.g.,
munitions) were found at only 5 of the 51 landfills (10
percent).
-------
Highlight 3 lists typical municipal and military wastes,
including:
(1) Wastes that are common to both municipal landfills
and military landfills;
(2) Wastes that are usually specific to military bases
but that do not necessarily pose higher risks than
other industrial wastes commonly found in mun-
icipal landfills (i.e., low-hazard military-specific
wastes), depending on the volume and heterogeneity
of the wastes; and
(3) High-hazard military wastes that, because of their
unique characteristics, would require special consi-
deration (i.e., high-hazard military-specific wastes).
The proportion and distribution of hazardous wastes in a
landfill are important considerations. Generally, muni-
cipal landfills produce low-level threats with occasional
hot spots. Similarly, most military landfills present only
low-level threats with pockets of some high-hazard
waste. However, some military facilities (e.g., weapons
'fabrication or testing, shipbuilding, major aircraft or
equipment repair depots) have a high level of industrial
activity compared to overall site activities. In these cases,
«there may be a higher proportion and wider distribution
of industrial (i.e., potentially hazardous) wastes present
than at other less industrialized facilities.
Sensitive Environments
Site-specific conditions may limit the use of the contain-
ment presumptive remedy at military landfills. For
(example, the presence of high water tables, wetlands
and other sensitive environments, and the possible
destruction or alteration of existing habitats as a result
of a particular remedial action could all be important
factors in the selection of the remedy.
Land Use
Reasonably anticipated future land use is also an impor-
tant consideration at all sites. However, at military bases
undergoing base closure procedures, where expedi-
tiously converting property to civilian use is one of the
primary goals, land use may receive heightened atten-
tion. Thus, at bases that are closing, it is particularly
important for reuse planning to proceed concurrently
with environmental investigation and restoration activ-
ities. The local reuse group is responsible for developing
the preferred reuse alternatives. The Base Realignment
and Closure Team should work closely with the reuse
group to integrate reuse planning into the cleanup
process, where practicable (see the Land Use in CERCLA
Remedy Selection directive).
Highlights
Examples of Municipal-Type
and Military-Specific Wastes
JMuniclpalifype Wastes
Municipal landfills contain predominantly non-
hazardous materials. However, industrial solid waste
and even some household refuse (e.g., pesticides,
paints, and solvents) can possess hazardous
components. Further, hazardous wastes are found in
most municipal landfills as a result of past disposal
practices.
Predominant Constituents
Household refuse, garbage, and debris
Commercial refuse, garbage, and debris
Construction debris
Yard wastes
Found in Low Proportion
Asbestos
Batteries
Hospital wastes
Industrial solid waste(s)
Paints and paint thinner
Pesticides
Transformer oils
Other solvents
JM i I i ta ry*S pec if Ic :Wa^s t es;
The majority of military landfills contain primarily
nonhazardous wastes. The materials listed in this
column are rarely predominant constituents of .
military landfills. ." , " . .
Low-Hazard Military-Specific Wastes
These rypes of wastes are specific to military bases
but generally are no more hazardous than some
wastes found in municipal landfills.
Low-level radioactive wastes
Decontamination kits
Munitions hardware
High-Hazard Military-Specific Wastes
These wastes are extremely hazardous and may
possess unique safety, risk, and toxicity character-
istics. Special consideration and expertise are
required to address these wastes.
Military Munitions
Chemical warfare agents
(e.g., mustard gas, tear agents)
Chemical warfare agent training kits
Artillery, small arms, bombs
Other military chemicals
(e.g., demolition charges,
pyrotechnics, propellants)
. Smoke grenades
-------
Highlight 4
Decision Framework
Collect Available Information
Waste Typos
Operating History
Monitoring Data
State Permit/Closure
Land Reuse Plans
Size/Volume
Number of Facility Landfills
Consider Effects of Land
Reuse Plans on Remedy
Selection
Do Landfill
Contents Meet
Municipal-Type
Waste
Definition?
Military-Specific Wastes
Are Present; Consult
With Military Waste Experts
t>
Excavation
of Contents S
N Practical?
4,, \ /
Not*: Site-specjflc
factors such as
hydrogeology. volume.
cost, and safety affect trie
practicality of excavation
of landfill contents.
Note: Site investigation
or attempted treatment
may not ba appropriate;
these activities may
cause greater risk than
leaving waste in place.
Containment
the Most
"Appropriate
Remedy?
Don't UM
Containment
Presumptive
Remedy
(A conventional
RI/FS is required.)
USE CONTAINMENT PRESUMPTIVE REMEDY
(A streamlined risk assessment and
focused feasibility study are used.)
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VTH E: rE$XJ [Wf?
This Section and Highlight 4 describe the steps involved
in determining whether the containment presumptive
remedy applies to a specific military landfill.
1. What Information Should Be Collected? Determine
the sources, types, and volumes of landfill wastes using
historical records, state files, closure plans, available
sampling data, etc. This information should be sufficient
to determine whether source containment is the appro-
priate remedy for the landfill. If adequate data do not
exist, it may be necessary to collect additional sampling
or monitoring data. The installation point of contact
(environmental coordinator, base civil engineer, or
public works office) should be contacted to obtain
records of disposal practices. Current and former em-
ployees are also good sources of information.
2. How May Land Reuse Plans Affect Remedy
Selection? For smaller landfills (generally less than
two acres), land reuse plans may influence the decision
on the practicality of excavation and consolidation or
treatment of landfill contents. Excavation is a remedial
alternative that is fundamentally incompatible with the
presumptive remedy of source containment.
3. Do Landfill Contents Meet Municipal Landfill-Type
Waste Definition? To determine whether a specific
military landfill is appropriate for application of the
containment presumptive remedy, compare the char-
acteristics of the wastes to the information in Highlights
2 and 3.
4. Are Military-Specific Wastes Present? Military
wastes, especially high-hazard military wastes, may
possess unique safety, risk, and toxicity characteristics.
Highlight 3 presents examples of these types of ma-
terials. If historical records or sampling data indicate
that these wastes may have been disposed at the site,
special consideration should be given to their handling
and remediation. Caution is warranted because site
investigation or attempted treatment of these con-
taminants may pose safety issues for site workers and
the community. Some high-hazard military-specific
wastes could be considered to present low-level risk,
depending on the location, volume, and concentration of
these materials relative to environmental receptors.
Consult specialists in military wastes (see Highlight 5)
when determining whether military-specific wastes at a
site fall into either the low-hazard or the high-hazard
military-specific waste category found in Highlight 3.
Highlights
Specialists in Military Wastes
The installation point of contact will notify the
major military command's specialists in military
wastes (Explosive Ordnance Disposal Team) for
assistance with regard to safety and disposal
issues related to any type of military items.
Army chemical warfare agents specialists:
' Project Manager, Non-Stockpile Chemical
Materiel, Aberdeen Proving Ground, Maryland
21010-5401, (410) 671-1083.
Navy ordnance related items specialists:
• The Navy Ordnance Environmental Support
Office, Naval Surface Warfare Center, Indian
Head. Maryland 20460-5035, (301) 743-45347
4906/4450.
Navy low-level radioactive wastes specialists:
• The Naval Sea Systems Command
Detachment, Radiological Affairs Support
Office, Yorktown, Virginia 23691-0260.
(804) 887-4692.
Air Force ordnance specialists:
• The Air Force Civil Engineering Support
Agency. Contingency Support Division,
Tyndall AFB. Florida 32403-5319,
(904) 283-6410.
Responsibilities for response are clearly spelled out in
the regulation Interservice Responsibilities For Explo-
sive Ordnance Disposal.
5. Is Excavation of Contents Practical? The volume
of landfill contents, types of wastes, hydrogeology, and
safety must be considered when assessing the practicality
of excavation and consolidation or treatment of wastes.
Consideration of excavation must balance the long-term
benefits of lower operation and maintenance costs and
unrestricted land use with the initial high capital con-
struction costs and potential risks associated with
excavation. Although no set excavation volume limit
exists, landfills with a content of more than 100,000
cubic yards (approximately two acres, 30 feet deep)
would normally not be considered for excavation. If
military wastes are present, especially high-hazard
military wastes such as ordnance, safety considerations
may be very important in determining the practicality of
excavation.
-------
If excavation of the landfill contents is being considered
as an alternative, the presumptive remedy should not be
used. Therefore, a standard RI/FS would be required to
adequately analyze and select the appropriate remedial
actions.
6. Can the Presumptive Remedy Be Used? The site
manager will make the initial decision of whether a
particular military landfill site is suitable for the presum-
ptive remedy or whether a more comprehensive RI/FS is
required. This determination must be made before the
RI/FS is initiated. This decision will depend on whether
the site is a potential candidate for excavation, and if
not, whether the nature of contamination is such that a
streamlined risk evaluation can be conducted.* A site
generally is eligible for a streamlined risk evaluation if
groundwater contaminant concentrations clearly exceed
chemical-specific standards or the Agency's level of risk
or if other conditions exist that provide a justification
for action (e.g., direct contact with landfill contents due
to unstable slopes). If these conditions do not exist, a
quantitative risk assessment that addresses all exposure
pathways will be necessary to determine whether action
is needed. Before work on the RI/FS workplan is
initiated, the community and state should be notified
that a presumptive remedy is being considered for the
site. It is important for all stakeholders to understand
completely how the presumptive remedy process varies
from the usual clean-up process, and the benefits of using
the presumptive remedy process.
TREATING "MOT SPOTS'
The presumptive remedy also allows for the treatment
of hot spots containing military-specific (or other) waste.
While the analysis, Feasibility Study Analysis for
CERCLA Municipal Landfill Sites, that justified the
selection of source .containment as the presumptive
remedy for municipal landfill sites did not specifically
take into account high-hazard military wastes, the high-
hazard materials present in some military landfills may
be compared to the hazardous wastes at municipal
landfills and could potentially be treated as hot spots.
For further information and case studies on treatment of
hot spots, see the Presumptive Remedy for CERCLA
Municipal Landfill Sites directive.
CASE HISTORIES
The case histories below illustrate how use of the
municipal landfill presumptive remedy at military
landfills follows the decision framework in Highlight 4.
' Sec Role of the Baseline Risk Assessment in Superfund Remedy
Selection Decisions, which states that if MCLs or non-zero
MCLGs are exceeded [a response] action generally is warranted.
The decision to use the presumptive remedy can be made
for one landfill or as a part of a site-wide strategy (as in
the Loring Air Force Base example below), depending
on factors such as the nature of the wastes, size of the
landfill, land reuse potential, and public acceptance.
The following case histories present examples of where
the containment presumptive remedy was or was not
applied, based on site-specific conditions.
Disposal of Municipal-Type Wastes
The Naval Reactor Facility (NRF) site in Idaho Falls,
Idaho, was established in 1949 as a testing site for the
nuclear propulsion program. The three landfill units at
the site received solid wastes similar to municipal
landfills. These wastes included petroleum and paint
products, construction debris, and cafeteria wastes.
Historical records do not indicate that any .radioactive
wastes were disposed of in these landfill units. The
selected remedy for the landfills at the site included the
installation of a 24-inch native soil cover designed to
incorporate erosion control measures to reduce the
effects from rain and wind. The remedy also provided
for maintenance of the landfill covers, including sub-
sidence correction and erosion control. Monitoring of
the landfills will include sampling of soil gas to assess
the effectiveness of the cover and sampling of the
groundwater to ensure that the remedy remains pro-
tective. Institutional controls will also be implemented
to prevent direct exposure to the landfill. The NRF site
is an example of where the streamlining principles of
the presumptive remedy process, including a streamlined
risk assessment and a focused feasibility study, were
successfully employed.
Co-Disposal of High-Hazard Wastes
At the Massachusetts Military Reservation, in Cape
Cod, Massachusetts, anecdotal information indicated
that munitions had been disposed of at an unidentified
location in a landfill that primarily contained municipal-
type waste. Ground penetrating radar was utilized to
determine if there were any discrete disposal areas
containing potential hot spots at this site and found none.
Because the munitions waste was not in a known discrete
and accessible area, it could not be treated as a hot spot.
Consequently, without excavating or treating the muni-
tions waste as a hot spot, the authorities decided to cap
the landfill. In this case, the streamlining principles of
the presumptive remedy process were applied. For
example, site investigation was limited and treatment
options were not considered.
-------
Land Reuse Considerations
At Loring Air Force Base, a closing base in Limestone,
Maine, base landfills 2 and 3 (9 and 17 acres, respective-
ly) consisted primarily of municipal and flightline
wastes. The selected remedy for these landfills included
a multi-layer cap, passive venting system, and institu-
tional controls. The RODs for the landfills, signed in
September 1994, required placing a RCRA Subtitle C
cap on the landfills. To construct the RCRA cap, the
designers estimated that 400,000 to 600,000 cyds of
material would have to be placed on the landfills prior to
construction of the cap to ensure proper drainage and
slopes.
At Loring, the streamlining principles of the containment
remedy, a focused feasibility study, and a streamlined
risk assessment were applied for landfills 2 and 3.
Additionally, the RODs signed for these landfills speci-
fied that excavated material from other parts of the base
would be used at the landfills to meet subgrade design
specifications. To date, more than 500,000 cyds of
contaminated soils have been excavated and used as sub-
grade for the landfills (after demonstrating compliance
with RCRA Land Disposal Restrictions). In addition to
cost savings realized by providing subgrade, other
benefits have been realized, such as limiting the number
of parcels requiring deed restrictions and minimizing
locations requiring operation and maintenance. At this
base, the landfill consolidation efforts resulted in an
estimated total cost savings of SI2-20 million while
incorporating future land use considerations into the
decision process.
The Brunswick Naval Air Station in Brunswick,
Maine, contained several landfill sites. One of the first
RODs signed, for Sites 1 and 3, called for construction
of a 12-acre RCRA Subtitle C cap and a slurry wall, as
well as for groundwater extraction and treatment.
Subsequently, during the remedy selection process for
Site 8, the public objected to containment as the proposed
remedy for this relatively small (0.6 acre) site on the
grounds that should the base eventually close, contain-
ment would create several useless parcels of land. After
public comment, the Navy reconsidered, proposing
instead to excavate Site 8 and consolidate the removed
materials (which consisted of construction debris and
soil contaminated with nonhazardous levels of poly-
cyclic aromatic hydrocarbons) as part of the necessary
subgrade fill for the landfill cap to be constructed at
Sites 1 and 3. In this case, land reuse considerations
preempted the selection of a containment remedy.
As stated earlier, it must be determined whether the
military landfill in question contains military-specific
wastes, as described in Highlight 3. This should be
followed by a determination of whether anything about
these wastes would make the engineering controls
specified in the presumptive remedy for municipal
landfills less suitable at that site. These determinations
must be documented in the administrative record, which
supports the final decision. This information, in turn,
will assist the public in understanding the evaluation of
the site as a candidate for use of the presumptive remedy
and the advantage it provides. For further reference, the
administrative record requirements for all Superfund
sites including military- landfills are explained in the
Final Guidance on Administrative Records for Selecting
CERCLA Response Actions.
The administrative record must contain the following
generic and site-specific information, which documents
the selection or non-selection of the containment pre-
sumptive remedy.
Generic Information
A. Generic Documents. These documents should be
placed in the docket for each federal facility site
where the containment presumptive remedy is
selected. Each EPA Regional Office has copies of
the following presumptive remedy documents:
Presumptive Remedy: Policy and Procedures
• Presumptive Remedy for CERCLA Municipal
Landfill Sites
• Application of the Municipal Landfill Pre-
sumptive Remedy to Military Landfills
• Feasibility Study Analysis for CERCLA Muni-
cipal Landfill Sites
8. Notice Regarding Backup File. The docket should
include a notice specifying the location of and times
when public access is available to the generic file of
backup materials used in developing the Feasibility
Study Analysis for CERCLA Municipal Landfill
Sites. This file contains background materials such
as technical references and portions of the feasi-
bility studies used in the generic study. Each EPA
Regional Office has a copy of this file.
-------
Site-specific Information
Focusad FS or EE/CA. Military-specific wastes need
to be addressed in site-specific analyses when determin-
ing the applicability of the containment presumptive
remedy to military landfills. High-hazard military-
specific waste materials (e.g., military munitions) require
special consideration when applying the presumptive
remedy.
As noted on pages 1 and 2 of this directive, the pre-
sumptive remedy approach allows you to streamline and
focus the FS or EE/CA by eliminating the technology
screening step from the feasibility study process. EPA
has already conducted this step on a generic basis in the
Feasibility Study Analysis for CERCLA Municipal
Landfill Sites. Thus, the FS analyzes only alternatives
comprised of components of the containment remedy
identified in Highlight 1. In addition, the focused FS or
EE/CA should include a site-specific explanation of how
the application of the presumptive remedy satisfies the
National Contingency Plan's three site-specific remedy
selection criteria (i.e., compliance with state applicable
or relevant and appropriate requirements, state accept-
ance, and community acceptance).
CONCLUSION
ft!/,
This directive provides guidance for the use of the
containment presumptive remedy at appropriate military
landfills. The remedies selected at numerous military
installations indicate that source containment is appli-
cable to a significant number of military landfills. These
landfills need not be identical to municipal landfills in
all regards. Key factors determining whether the con-
tainment presumptive remedy should be applied to a
specific military landfill include the size of the landfill;
volume and the type of landfill contents; future land use
of the area; and the presence, proportion, and distribution
of military-specific wastes.
REFERENCES
California Base Closure Environmental Committee, Inte-
grating Land Use and Cleanup Planning at Closing Bases,
December 1994.
Federal Register, 1996. Volume 61, No. 85, May 1,1996;
Corrective Action for Releases from Solid Waste Manage-
ment Units at Hazardous Waste Management Facilities.
Advance Notice of Proposed Rulemaldng.
Federal Register, 1990. Volume 55, No. 145, July 27,1990;
40 CFR Parts 264,265,270 and 271; Corrective Action for
Solid Waste Management Units at Hazardous Waste Facili-
ties; Proposed (proposed Subpart S regulations).
U.S. Environmental Protection Agency, OSWER Directive
93557-04, Land Use in the CERCLA Remedy Selection,
May 25, 1995.
U.S. Environmental Protection Agency, OSWER Directive
9356.0-03, EPA/540/R-94/081, Feasibility Study Analy-
sis for CERCLA Municipal Landfill Sites, August 1994.
U.S. Environmental Protection Agency, OSWER Directive
9902.3-2A,EPA/520/R-94/004, RCRA Corrective Action
Plan, May 1994.
U.S. Environmental Protection Agency, OSWER Directive
9355.0-49FS, Presumptive Remedy for CERCLA Muni-
cipal Landfill Sites, September 1993.
U.S. Environmental Protection Agency, OSWER Directive
9355.0-47FS, EPA/540/F-93/047, Presumptive Remedy:
Policy and Procedures, September, 1993.
U.S. Environmental Protection Agency, OSWER Publi-
cation 9380.3-06FS, Guide to Principal Threat and Law
Level Threat Wastes, November 1991.
U.S. Environmental Protection Agency, OSWER Directive
9355.0-30, Role of the Baseline Risk Assessment in Super-
fund Remedy Selection Decisions, April 22,1991.
U.S. Environmental Protection Agency, OERR, EPA/540/
P-91/001, Conducting Remedial Investigations/Feasibility
Studies for CERCLA Municipal Landfill Sites, February
1991. '.
U.S. Environmental Protection Agency, OSWER Directive
9833.3 A. 1, Final Guidance on Administrative Records for
Selecting CERCLA Response Actions, December 3,1990.
U.S. Environmental Protection Agency, OSWER Directive
9355.3-11FS, Streamlining the RI/FSfor CERCLA Muni-
cipal Landfill Sites, September 1990.
U.S. Department of Navy, Interservice Responsibilities
for Explosive Ordnance Disposal OPNAVINST 8027.1G
(also known as MCO 8027.1D, AR 75-14; or APR 32-
3002), February 14,1992.
NOTICE
The policies set out in this document are intended
solely as guidance to the EPA personnel; they are not
final EPA actions and do not constitute rulemaking.
These policies 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 docu-
ment, or to act at variance with the guidance, based on
an, analysis of specific site circumstances. EPA also
reserves the right to change this guidance at any time
without public notice.
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DATA SUMMARY TABLE FOR MILITARY LANDFILLS APPENDIX
ROD /Site Name, State,
Region, ROD Sign Date
Brunswick NAS, Sites 1
and 3 (OU1), ME,
Region 1
6/16/92
Brunswick NAS, Sites 5
and 6 (OU3), ME,
Region 1
8/31/93
Brunswick NAS, Sites 5
and 6 (OU3). ME,
Region 1 .
8/31/93
Brunswick NAS, Site 8
(OU4), ME, Region 1
8/31/93
Loring AFB, Landfills 2
and 3 (OU2), ME,
Region 1
9/30/94
Loring AFB, Landfills 2
and 3 (OU2), ME,
Region 1
9/30/94
Disposal Area, Size,
Volume of Waste
Site 1,8.5 acres; Site 3, 1.5
acres. Sites are in close
proximity and not easily
distinguishable; the
combined volume of Sites 1
and 3 is 300,000 cv
Site 5, 0.25 acres, 12cy
Site 6, 1. 0 acre, 8,800 -
1 8,700 cy
Site 8, 0.6 acres, 5,600 -
1 4.000 cy
Landfill 2, 9 acres
Landfill 3, 17 acres
Type of Waste
Deposited
Household refuse, waste
oil, solvents, pesticides,
paints, isopropyl alcohol
Asbestos-covered pipes
Construction debris, and
aircraft parts, asbestos
pipes
Rubble, debris, trash, and
possibly solvents
Domestic waste,
construction debris,
flightline wastes, sewage
sludge and oil-filled
switches
Waste oil/fuels, solvents,
paints, thinners, and
hydraulic fluids
Contaminants of
Concern
Metals, VOCs,
PAHs, PCBs,
pesticides
Asbestos
Asbestos
Metals,
pesticides, PCBs1
PCBs, VOCs,
SVOCs, metals,
DDT1
VOCs. SVOCs.
DDT. PCBs, .
metals'
Remedy
Remedy: Capping (permanent, low-permeability, RCRA Subtitle
C cap), of 12 acres with a slurry wall and pump and treat ground
water within cap and slurry wall.
Remedy: Excavation, containerization, and transport to landfill
Sites 1 and 3 for use as fill under cap.
*•>.. '>
Remedy: Excavation, containerization, and transport to Sites 1
and 3 landfill for use as fill under cap.
Remedy: Excavation, containerization, and transport to landfill
Sites 1 and 3 for use as fill under cap.
Remedy: Capping (low-permeability cover system which meets
RCRA Subtitle C and Maine hazardous waste landfill cap
requirements), passive gas venting system and controls, and
institutional controls.
Remedy: Capping (low-permeability cover system which meets
RCRA Subtitle C and Maine hazardous waste landfill cap
requirements), passive gas venting system and controls, and
institutional controls.
Contaminants of Potential Concern
A-l
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DATA SUMMARY TABLE FOR MILITARY LANDFILLS APPENDIX (CONT.)
ROD /Site Name, State,
Region, ROD Slqn Date
Newport Naval Education
and Training Center,
•McAllister Point Landfill.
Rl, Region 1
9/27/93
Otis Air National Guard,
Camp Edwards,
Massachusetts Military
Reservation, MA,
Region 1
1/14/93
Pease AFB(OU1),NH.
Region 1
9/27/93
Fort Dix Landfill Site, NJ,
Region 2
9/24/91
Naval Air Engineering
Center (OU3). NJ,
Region 2
9/16/91
Naval Air Engineering
Center (OU3), NJ,
Region 2
9/16/91
Disposal Area, Size,
Volume of Waste
McAllister Point Landfill,
11. 5 acres
Landfill Number 1 (LF-1),
100 acres
LF-5, 23 acres
Main area, 126 acres
Site 26, 1500 sq. ft., volume
not reported
Site 27, 6.4 acres
Type of Waste
Deposited
Domestic refuse, spent
acids, paints, solvents,
waste oils, and PCB-
contaminated transformer
oil
General refuse, fuel tank
sludge, herbicides, blank
ammunition, paints, paint
thinners, batteries, DDT,
hospital wastes, sewage
sludge, coal ash, possibly
live ordnance
Domestic and industrial
wastes, waste oils and
solvents, and industrial
wastewater treatment
plant sludqe
Domestic waste, paints
and paint thinners,
demolition debris, ash,
and solvents
Oil, roofing materials,
building debris
Scrap steel cable
Contaminants of
Concern
VOCs, PAHs,
PCBs, pesticides,
phenols, metals
VOCs. SVOCs,
inorganics
VOCs. PAHs,
arsenic and other
metals
VOCs, metals
No contamination
was detected
No contamination
was detected
Remedy
Remedy: Capping (RCRA Subtitle C, multi-layer cap), landfill gas
management, surface controls, and institutional controls.
Remedy: Capping (composite-low-permeability cover system),
institutional controls, soil cover inspection, and ground water
monitoring.
Remedy: Excavation, dewatering and consolidation and
regrading of waste under a composite-barrier type cap,
institutional controls, and extraction and treatment of ground water
with discharge to base wastewater treatment facility.
Remedy: Capping 50-acre portion (New Jersey Administrative
Code 7:26 closure plan for hazardous waste), installing gas
venting system and an air monitoring system, ground water,
surface water, and air monitoring, and institutional controls.
Remedy: Source: No action.
Remedy: Source: No action.
A-2
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DATA SUMMARY TABLE FOR MILITARY LANDFILLS APPENDIX (CONT.)
ROD/Site Name, State,
Region, ROD Sign Date
Disposal Area, Size,
Volume of Waste
Type of Waste
Deposited
Contaminants of
Concern
Remedy
Naval Air Engineering
Center (OU17). NJ,
Region 2
9/26/94
Site 29,20 acres
Construction debris,
metal, asbestos, solvents,
other miscellaneous
wastes
VOCs. SVOCs,
metals
Remedy: Source: No action.
Pittsburgh AFB, LF-022,
NY, Region 2
9/30/92
LF-022, approx. 13.7 acres,
approx. 524,000 cy
Household refuse
Metals, pesticides
Remedy: Capping (NY State requirements for solid waste
landfills, 12 inch soil cap), and institutional controls.
Pittsburgh AFB, LF-023,
NY, Region 2
9/30/92
LF-023, approx. 9 acres,
approx. 406,000 cy
Household refuse, debris,
car parts
Metals, VOCs,
SVOCs. PCS,
pesticides
Remedy: Capping (NY State requirements for solid waste
landfills, low permeability cap), and institutional controls.
U.S. Army Aberdeen
Proving Grounds (OU 1),
MO, Region 3
Michaelsville Landfill, 20
acres, greater than
100,000 cy
Household refuse, limited
quantities of industrial
waste, burned sludges,
pesticide containers,
paint, asbestos shingles,
solvents, waste motor
oils, grease, PCB
transformer oils, possible
pesticides
Metals,
pesticides, VOCs,
PCBs, PAHs
Remedy: Capping (multi-layer cap in accordance with MDE
requirements for sanitary landfills, using a geosynthetic
membrane, 0-2 feet compacted earth material), surface water
controls, and gas venting system.
6/30/92
Marine Corps Base,
CampLejeune(OUI),
NC, Region 4
9/15/94
Site 24,100 acres, volume
not reported
Fly ash, cinders, solvents,
used paint stripping
compounds, sewage
sludge, spiractor sludge,
construction debris
Pesticides,
metals, SVOCs,
PCBs
Remedy: Source: No action.
Robins AFB (OU1).GA.
Region 4
6/25/91
Main area (Landfill No. 4),
45 acres, greater than
100,000 cy
Household refuse,
industrial waste
VOCs, metals
Remedy: Capping (to maintain a minimum 2-foot cover over the
waste materials), renovation of current soil cover including
clearing, filling, regrading, adding soil and clay cover material and
seeding to maintain a minimum 2-foot cover over the waste
material.
A-3
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DATA SUMMARY TABLE FOR MILITARY LANDFILLS APPENDIX (CONT.)
ROD /Site Name, State,
Region, ROD Sign Date
Disposal Area, Size,
Volume of Waste
Type of Waste
Deposited
Contaminants of
Concern
Remedy
Twin Cities AFB Reserve,
MN, Region 5
3/31/92
Main area, approx. 2 acres,
volume not reported
Household refuse, small
amounts of industrial;
some burned waste
VOCs, metals
Remedy: Source: Institutional controls, natural attenuation,
ground water and surface water monitoring.
Wright-Patterson AFB,
(Source Control Operable
Unit) OH, Region 5
7/15/93
LF-8,11 acres, 187,300 cy
General refuse and
hazardous materials
PAHs, pesticides,
PCBs, VOCs,
metals,
inorganics
Remedy: Capping (low-permeability clay cap that complies with
Ohio EPA regulations for sanitary landfills which meet or exceed
RCRA Subtitle D requirements), institutional controls, ground
water treatment and monitoring.
Wright-Patterson AFB,
(Source Control Operable
Unit) OH, Region 5
7/15/93
LF-10,8acres, 171,600 cy
General refuse and
hazardous materials
PAHs, pesticides,
PCBs, VOCs,
metals,
inorganics
Remedy: Capping (low-permeability clay cap that complies with
Ohio EPA regulations for sanitary landfills which meet or exceed
RCRA Subtitle D requirements), institutional controls, ground
water treatment and monitoring.
Hill AFB (OU4), UT,
Region 8
6/14/94
Landfill 1,3.5 acres,
140,000 cy
Burned solid waste, small
amounts of waste oils
and solvents (from
vehicle maintenance
facility).
VOCs (TCE)
Remedy: Capping (clay or multi-media cap), pumping, treating,
and discharging ground water to POTW, treating contaminated
surface water, soil vapor extraction, implementing institutional
controls and access restrictions.
Defense Depot, Ogden
(OU1),UT. Regions
6/26/92
Plain City Canal Backfill
Area, 4,000 cy
Electrical wire, glass, ash,
charcoal, asphalt, wood,
concrete, plastic and
metal fragments
Metals, PCBs,
dioxins, furans,
VOCs
Remedy: Excavation, sorting, and off-site disposal in a RCRA
permitted facility.
Defense Depot, Ogden
(OU3), UT, Region 8
9/28/92 • "
Burial Site 3-A: Chemical
Warfare Agent Identification
Kit Burial Area, 100cy
Vials of chemical surety
agents, broken glass
Metals, chemical
warfare agents
Remedy: Excavation, sorting, and off-site disposal in a RCRA
permitted facility.
Defense Depot, Ogden
,{OU3), UT, Region 8
9/28/92 •..
Burial Site 3-A: Riot Control
and Smoke Grenade Burial
Area, 90 cy
Unfused grenades and
grenade fragments, as
well as riot control
grenades
No contaminants
identified
Remedy: Excavation, sorting, and off-site disposal in a RCRA
permitted facility.
A-4
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ROD / Site Name, State,
Region, ROD Sign Date
Disposal Area, Size,
Volume of Waste
Type of Waste
Deposited
Contaminants of
Concern
Remedy
Defense Depot, Ogden
(OU3), UT, Region 8
Burial Site 3-A:
Compressed Gas Cylinder
Reburial Area
Two compressed gas
cylinders and four smaller
steel tanks removed from
the Chemical Warfare
Agent Identification Kit
and Riot Control and
Smoke Grenade burial
areas
Unknown,
possible chemical
warfare agents
Remedy: Excavation of compressed gas cylinders and disposal
by a commercial operator.
9/28/92
Defense Depot, Ogden
(OU3), UT, Region 8
9/28/92
Burial Site 3-A:
Miscellaneous Items Burial
Area, 230 cy
Chemical Warfare Agent
Identification Kits
containing no CWAs,
World War II gas mask
canisters, paint, broken
glass, wooden boxes,
and pieces of iron
No contaminants
identified
Remedy: Excavation and transportation for off-site disposal in a
RCRA permitted hazardous waste landfill.
Defense Depot, Ogden
(OU3), UT, Region 8
9/28/92
Water Purification Tablet
Burial Area, 110cy
Bottles containing
halazone water
purification tablets
No contaminants
identified
Remedy: Excavation and transportation for off-site disposal in a
RCRA permitted industrial waste landfill.
-Defense Depot, Ogden
(OU4). UT, Region 8
9/28/92
4-A, 7500, sq. ft., 3000 cy
Wood, crating materials,
paper, greases, debris,
medical waste, oils, .some
burned waste
Pesticides, VOCs,
PCBs
Remedy: Excavation and transportation for off-site disposal in a
RCRA permitted hazardous waste landfill.
Defense Depot, Ogden
(OU4), UT, Region 8
9/28/92
4-B, (inside 4-E), less than
7,500, sq. ft.
Fluorescent tubes
No contaminants
identified
Remedy: Excavation and transportation for off-site disposal in a
RCRA permitted landfill.
Defense Depot, Ogden
(OU4), UT, Region 8
9/28/92
4-C, 6,000 sq. ft
Food products, sanitary
landfill waste
Pesticides, VOCs,
PCBs
Remedy: Excavation and transportation for off-site disposal in a
RCRA permitted landfill.
A-5
-------
e
ROD/i ame, State,
Region. ROD Sign Date
Disposal Area, Size,
Volume of Waste
Type of Waste
Deposited
Contaminants of
Concern
Remedy
Defense Depot, Ogden
(OU4), UT, Region 8
9/28/92
4-D, 2,000 sq. ft.
Methyl bromide cylinders,
halazone tablets (jars)
Possibly methyl
bromide
Remedy: Excavation and transportation for off-site disposal in a
RCRA permitted industrial landfill.
Defense Depot, Ogden
(OU4), UT, Region 8
9/28/92
4-E. 7,500 sq. ft., volume
not reported
Oils, spent solvents,
industrial waste
PCBs, VOCs,
pesticides
Remedy: Excavation and transportation for off-site disposal in a
RCRA permitted hazardous landfill.
Rocky Mountain Arsenal,
Shell Section 36
Trenches (OU23), CO,
Region 8
5/3/90
Shell Trench Area, 8 acres
Rags, plastic and metal
cans, glass jars, piping,
pipe fittings, insulation,
refuse, insulation, liquid
and solid wastes
generated from the
manufacture of pesticides
VOCs. SVOCs,
pesticides2
Remedy: Capping (physical barrier with a soil and vegetative
cover).
Fort Ord Landfills (OU2),
CA, Region 9
Landfills, 150 acres
8/23/94
Household and
commercial refuse, dried
sewage sludge,
construction debris, small
amounts of chemical
waste including paint, oil,
pesticides, and epoxy
adhesive, electrical
equipment
VOCs
Remedy: Capping (California Code of Regulations for non-
hazardous waste), institutional controls, extraction, treatment, and
recharge of ground water.
Riverbank Army
Ammunition Plant Site,
CA, Region 9
3/24/94
Landfill, 4.5 acres
Paper, oils, greases.,
solvents, hospital wastes,
construction debris, and
industrial sludges
Me'tafs
Remedy: Capping (a multi-layer cap as specified in Dispute
Resolution Agreement), pump and treat ground water, discharge
treated water to on-site ponds.
2 Contaminants identified as emanating from the trenches but not contaminants of concern
A-6
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DATA SUMMARY TABLE FOR MILITARY LANDFILLS APPENDIX (CONT.)
HOU / bite Name, state,
Region. ROD Sign Date
Wi Ilia mo A PR tr\\ H \ A *?
Region 9
6/18/94
Region 9
5/18/94
wiinams Mrt> (UUi), AZ,
Region 9
5/18/94
AK, Region 10
9/29/94
cimenuon Mro (UU1),
AK, Region 10
9/29/94
Elmendorf AFB (OU1),
AK, Region 10
9/29/94
Disposal Area, Size,
Volume of Waste
Landfill LF-04, 90 acres,
59,000 cy
Pesticide Burial Area (DP-
13), 0.4 acre
Radioactive Instrumentation
Burial Area (RW-11), 100
sq.ft.
LF05, 17 acres
LF07, 35 acres
-F 13, 2 acres
Type of Waste
Deposited
Dried sewage sludge,
domestic trash and
garbage, wood, metal,
brush, construction
debris, some solvents
and chemicals
Pesticides
Cement; radioactive
instruments
General refuse, scrap
metal, used chemicals
and other scrap material
Base generated refuse,
scrap metal, construction
rubble, drums of asphalt,
empty pesticide
containers, small
amounts of shop wastes,
and asbestos wastes
Empty drums, metal
piping, drums of asphalt,
and small quantities of
quicklime
Contaminants of
Concern
Soil, pesticides,
SVOCs,
inorganics,
including
beryllium, lead,
zinc
Pesticides, VOCs,
metals
Radium
(background
levels)
VOCs, PCBs,
metals, PAHs
VOCs, PCBs,
metals, PAHs
»'
VOCs, PCBs,
metals, PAHs
Remedy
Remedy: Capping (a permeable cap with a 24 inch soil cover),
stormwater runoff controls, institutional actions, and soil and
ground water monitoring.
Remedy: Source: No action.
Remedy: Source: No action.
Remedy: Source: No action.
Remedy: Source: No action.
Remedy: Source: No action.
*
A-7
-------
e
DATA SUMMARY TABLE FOR Mi IY LANDFILLS APPENDIX (CONT.)
ROD / Site Name, State,
Region, ROD Siqn Date
ElmendorfAFB(OUI),
AK, Region 10
9/29/94
FairchildAFB(OUI), WA,
Region 10
2/13/93
Fairchild AFB (OU1), WA,
Region 30
2/13/93
Fort Lewis Military
Reservation, Landfill 4
and the Solvent Refined
Coal Pilot Plant, WA,
Region 10
9/24/93
Naval Air Station,
Whidbey Island, Ault
Field (OU1), WA,
Region 10
12/20/93
Naval Air Station,
Whidbey Island, Ault
Field (OU2). WA,
Region 10
12/20/93
Disposal Area, Size,
Volume of Waste
LF59, 2 landfills (.5 acres
each)
Southwest area,
12.6 acres, 407.300 cy
Northeast area, 6 acres,
291. 000 cy
LF4, 52 acres
Area 6 Landfill, 40 acres.
Within Area 6 there are 2
distinct areas where wastes
were disposed.
Area 2, 13 acres; Area 3, -
1.5 acres. Both treated
together due to close
proximity.
Type of Waste
Deposited
General refuse and
construction debris, and
tar seep
Coal ash, solvents, dry
cleaning filters, paints,
thinners, possibly
electrical transformers.
Coal ash, solvents, dry
cleaning filters, paints,
thinners. possibly
electrical transformers.
Domestic and light
industrial solid waste (no
landfill records were
maintained).
Household waste,
construction debris, and
yard waste
Solid waste from the
base, industrial wastes,
and construction and
demolition debris
Contaminants of
Concern
VOCs. PCBs,
metals. PAHs
VQCs
VOCs
VOCs, metals
VOCs
Metals, PAHs
Remedy
Remedy: Source: No action.
Remedy: Capping (low-permeability cap designed to meet the
closure requirements of Washington State's Minimum Functional
Standards for Solid Waste handling and of federal RCRA Subtitle
D), SVE/ treatment system, extracting contaminated ground water
and treating by air stripping and granular activated carbon,
disposal off-site, monitoring off-site water supply wells.
Remedy: Capping (low-permeability cap designed to meet the
closure requirements of Washington State's Minimum Functional
Standards for Solid Waste handling and of federal RCRA Subtitle
D), SVE/ treatment system, extracting contaminated ground water
and treating by air stripping and granular activated carbon,
disposal off-site, monitoring off-site water supply wells.
Remedy: Source: Institutional controls, treat ground water and
soil using SVE and air sparging system.
Remedy: Capping (low-permeability cap to meet Washington
State Minimum Functional Standards for non-hazardous closure),
air stripping ground water, ground water monitoring, and
institutional controls.
Remedy: Source: Institutional controls, ground water monitoring.
A-8
-------
ROD /Site Name, State,
Region, ROD Sign Date
Naval Reactor Facility,
ID, Region 10
9/27/94
Naval Reactor Facility,
ID, Region 10
9/27/94
Naval Reactor Facility,
ID, Region 10
9/27/94
Disposal Area, Size,
Volume of Waste
Landfill Unit 8-05-1.
(350 ft. by 450 ft. by 4-25
ft.)
Landfill Unit 8-05-51,
(450ft. by 100 -175 ft. by
10-15 ft.)
Landfill Unit 8-06-53, (900
ft. by 1200 ft. by 7- 10 ft.)
Type of Waste
Deposited
Construction debris, small
quantities of paints,
solvents, cafeteria
wastes, and petroleum
products
Construction debris, small
quantities of paints,
solvents, cafeteria
wastes, and petroleum
products
Construction debris, small
quantities of paints,
solvents, cafeteria
wastes, and petroleum
products
Contaminants of
Concern
Metals, VOCs
Metals, VOCs
Metals, VOCs
Remedy
Remedy: Capping (24-inch native soil cover), institutional
controls.
Remedy: Capping (24-inch native soil cover), institutional
controls.
Remedy: Capping (24-inch native soil cover), institutional
controls.
A-9
-------
-------
4
United States Office of
Environmental Protection Solid Waste and
Agency Emergency Response
Publication 9203.1-021
April 1992
Superfund Accelerated
Bulletin
Presumptive Remedies for Municipal Landfall
Sites
Superfund Revitalization Activity
Office of Emergency and Remedial Response
Hazardous Site Control Division OS-220W
Intermittent Bulletin
Volume 1 Number 1
The Presumptive Remedy Selection Initiative
Since Supe^rund's inception in 1980, the removal and remedial programs have found that certain categories of sites have
similar characteristics, such as the types of contaminants present, past industrial use, or the environmental media that are
affected. Based on a wealth of information acquired from evaluating and cleaning up these sites, Superfund is undertaking
an initiative to develop presumptive remedies that are appropriate for specific types of sites, contaminants, or both. This
initiative is part of a larger program, known as the Superfund Accelerated Cleanup Model (SACM), which is designed to
speed all aspects of the Superfund clean-up process.
The objective of the presumptive remedies initiative is to use clean-up techniques shown to be effective in the past at similar
sites in the future. The use of presumptive remedies will streamline removal actions, site studies, and clean-up actions, thereby
improving consistency, reducing costs, and increasing the speed with which hazardous waste sites are remediated
The Municipal Landfill Pilot Project
Superfund kicked off a new pilot project designed to
expedite the site investigation and remedy selection
process for municipal landfills with a visit to
Region V on March 18-20,1992. Superfund
anticipates that remedy selection may
be streamlined for municipal landfills
because they typically share similar
characteristics and because con-
tainment and ground water
cleanup frequently is the appro-
priate remedy for these sites.
An existing EPA manual, Con-
ducting Remedial Investigations/
Feasibility Studies for CERCLA
Municipal Landfill Sites, outlines
streamlining techniques for municipal landfills. The goal
of the initiative is to aid the Regions in implementing the
manual, so that site characterization, the baseline risk
assessment, and the number of alternatives considered
will be streamlined at every municipal landfill site.
Albion Sheridan Township landfill, a municipal landfill in
Michigan, was the first site to participate in the pilot
Project. A team of Remedial Project Managers (RPMs) from
several Regions and experts on landfill construction met
with the site RPM in Grand Rapids, Michigan to develop
the site strategy. As a result of the meeting, site character-
ization will be conducted in a phased approach, with
Faster... CIean@fe..Saf@f
criteria established for when additional sampling will
occur. Streamlining of the baseline risk assessment will
depend upon data obtained in the first phase of
sampling.
Four other Superfund municipal
landfill sites have been identified
as candidates for participation in
the project: Lexington County
Landfill, Lexington County,
South Carolina (Region IV); BFI/
Rockingham, Rockingham, Ver-
mont (Region I); Sparta Landfill,
Sparta Township, Michigan (Re-
gion V); and Beulah Landfill,
Pensacola, Florida (Region IV).
The review team anticipates meeting with the RPMs for
these sites during April, May, and June 1992.
RPMs who participate in the project and implement the
municipal landfill manual at their sites will become mem-
bers of the team and will be available to assist other RPMs
in developing streamlined RI/FSs. These RPMs will be a
resource for their Regions, providing assistance in stream-
lining remedy selection at all future municipal landfill
sites.
Questions should be addressed to Andrea McLaughlin at
FTS 678-8365.
-------
-------
&EFA
United States
Environmental Protection
Agency
Off ice of
Solid Waste and
Emergency Response
Publication 9203.1-021
February 1993
Accelerated
Cleanup
Presumptive Remedies for Municipal Landfill
Sites
Office of Emergency and Remedial Response
Office of Waste Programs Enforcement
Intermittent Bulletin
Volume 2 Number 1
The Presumptive Remedy Selection Initiative
Since Superfund's inception in 1980, the removal and remedial programs have found that certain categories of sites have
similar characteristics, such as the types of contaminants present, past industrial use, or the environmental media that are
affected. Based on a wealth of information acquired from evaluating and cleaning up these sites, Superfund is undertakmg
an initiative to develop presumptive remedies that are appropriate for specific types of sites, contaminants, or both. Tlus
initiative is part of a larger program, known as the Superfund Accelerated Cleanup Model (SACM), which is designed to
speed all aspects of the Superfund clean-up process.
The objective of the presumptive remedies initiative is to use clean-up techniques shown to be effective in the past at similar
sites in the future The use of presumptive remedies will streamline removal actions, si te studies, and clean-up actions, thereby
improving consistency, reducing costs, and increasing the speed with which hazardous waste sites are remediated.
Purpose
The Superfund Municipal Landfill Expert Team has com-
pleted four site visits under the Municipal Landfill Pilot
Project.1 The pilot project implements a 1991 streamlining
manual, "Conducting Remedial Investigations/Feasibil-
ity Studies for CERCLA Municipal Landfill Sites" (hereaf-
ter referred to as "the manual"). This bulletin presents key
findings from the pilots completed to date, particularly
with respect to the level of detail that was appropriate for
establishing risk, and therefore a basis for reme-
dial action, at two of the sites.
Background
The preamble to the National Con- J&
tingency-Plan (NCP) identifies >
municipal landfills as a type of site *•
where treatment of the waste may *•*
be impracticable due to the size
and heterogeneity of the contents.
Because of this, containment will
often be the appropriate response
action for the source area of mu-
nicipal landfill sites. Such containment remedies are likely
to include a landfill cap; ground-water treatment or con-
trol; leachate collection and treatment; and landfill gas
collection and treatment, as appropriate.
The municipal landfill manual states that baseline risk
assessments at municipal landfill sites may be streamlined
or limited in order to initiate early remedial action on the
most obvious landfill problems (e.g., ground water/
leachate, landfill contents, and landfill gas). One method
for establishing risk using a streamlined approach is to
compare contaminant concentration levels (if available) to
standards that are potential chemical-specific applicable
or relevant and appropriate requirements (ARARs) for the
action. The manual states that where established standards
for one or more contaminants in a given medium
aredearly exceeded, remedial action is gen-
erally warranted.2 The manual further
states that ultimately it is necessary to
demonstrate that the final remedy
addresses all pathways and con-
taminantsof concern, not justthose
that triggered the remedial action.
Pilot Project Findings
The experience of the expert team
supports the usefulness of a lim-
ited risk assessment to initiate early
action at two of the pilot sites. Specifically, for the source
ajsa of these two sites (i.e., the discrete landfill area), a
quantitative risk assessment that considered all chemicals,
their potential additive effects, etc., was not necessary,
i S«« •Superfund Accelerated Cleanup Bulletin. Presumptive Remedies for Municipal Landfill Sites," Publication 9203.1-021, Volume 1. Number 1. Apnl
1092.
- See also OSWER Directive 9355.0-30. "Role of the Baseline Risk Assessment in Superfund Remedy Selection Decisions.- April 22,1991. which states that
tf MCLs or non-zero MCLGs are exceeded, (remedial) action generally is warranted.
-------
either to establish a basis for action or to establish clean-up
levels For these two sites, the justification for early reme-
dial action was based on existing ground-water data.
Ground-water data are notavailable for the other two sites.
Sites with Ground-water Data
For the source areas of the two sites with existing ground-
water data, the basis for action was ground-water contami-
nation at levels exceeding non-zero MCLGs or MCLs;
therefore, a complete quantitative risk assessment was not
necessary to establish risk (and therefore a basis for action)
at these sites. Furthermore, a quantitative risk assessment
was not needed to evaluate whether the containment rem-
edy addressed all pathways and contaminants of concern
associated with the source. Rather, all potential migration
pathways were identified (using theconceptual site model)
and compared to those addressed by the containment
remedy as follows:
• direct contact threat and surface water run-off ad-
dressed by capping;
• exposure to contaminated ground water (including
any contaminated ground water moving off-site)
addressed by ground-water treatment/control (in-
cluding assessment of current exposure); and
• exposure to landfill gas addressed by gas collection
and treatment:, as appropriate.
This comparison revealed that the containment remedy
addressed all pathways associated with the sources at
these sites.
Finally, a quantitative risk assessment was not required to
determine clean-up levels for the source areas, since the
type of cap will be determined by closure ARARs, and
ground-waterclean-up levels may be based on MCLs, non-
zero MCLGs, or more-stringent, promulgated, state levels.
NOTE: In some cases, a risk assessment may be required to
determine the risk associated with contaminants in landfill
gas. Landfill gas collection will frequently be a necessary
component of the remedy to insure cap integrity. There
may be an additional need for treatment of the collected
gas'based upon the contaminants present. In some cases,
itate ARARs may identify clean-up levels for such con-
taminants, and in some cases health-based levels will be
appropriate. This issue will be addressed in further detail
in future guidance.
Sites with No Existing Ground-water Data
Ground-waterdata are not yet available for twoof the pilot
sites, for these site:,, the following tiered approach was
recommended. Once ground-water data are obtained, a
clear basis for action may be established, and the remedy
selection may be streamlined as described for the two sites
with available ground-water data. If contaminants are not
identified above MCLs or non-zero MCLGs, however,
additional pathways, such as surface contamination and
landfill gas, will be characterized next, and a focused
quantitative risk assessment conducted toes tablisha basis
for remedial action.
Areas of Contaminant Migration
One of the expert team's key findings is that almost every
municipal landfill site has some unique characteristic that
may require additional study. Unique characteristics en-
countered during the pilot visits include leachate dis-
charge to a wetland atone site and significant surface water
run-off due to drainage problems at another. These path-
ways will require characterization and conventional risk'
assessment to determine whether remedial action is war-
ranted beyond the source area, and if so, the type of action
that is appropriate.
Pilot Study Findings and Conclusions
The expert team's conclusions from the four pilots, then,
are that:
(1) a quantitative risk assessment was not warranted
for the source areas of the two pilot sites where
ground-water data were available and contami
nants exceeded chemical-specific standards, justi-
fication for action was the exceedance of the stan-
dards;
Further, streamlining the risk assessment elimi-
nated the need for sampling and analysis of these
source areas to support the calculation of current
or future risk.
(2) a focused risk assessment generally will be neces-
sary for areas other than the landfill source itself
(such as areas where contaminants have migrated
from the source) to determine the need for addi-
tional remedial action beyond areas normally ad-
dressed by the cap; and
(3) a focused risk assessment generally will be neces-
sary to determine the need for remedial action at
sites where ground-water concentrations do not
exceed MCLs or non-zero MCLGs, unless other
conditions provide a clear justification (e.g. un-
stable slopes).
These conclusions are directly applicable to the four pilot
sites only; however, based on these findings, the municipal
landfill expert team is developing an Agency d irective that
will provide additional guidance on conducting baseline
risk assessments at municipal landfill sites For addition?'
information on the directiveor the municipal landfill pile
project, please call Andrea McLaughlin at 703-603-8793.
-------
&EPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
9355.3-18FS
EPA/540/F-95/009
PB95-963412
August 1995
Presumptive Remedies:
CERCLA Landfill Caps Rl/FS
Data Collection Guide
Office of Emergency and Remedial Response
Hazardous Site Control Division (5203G)
Quick Reference Fact Sheet
Municipal landfills constitute approximately 20 percent of all sites on the Superfund National Priorities List. Approximately 75 percent
of all CERCLA Municipal Solid Waste Landfill (MSWLF) Remedial Actions call for installation of a landfill cap. The remedy
selection process for MSWLFs is the basis of a U.S. Environmental Protection Agency (EPA) guidance, Conducting Remedial
Investigations/Feasibility Studies for CERCLA Municipal Landfill Sites (U.S. EPA, 1991), which establishes the framework for
containment (including landfill cap construction, leachate collection and treatment, ground water treatment, and landfill gas collection
and treatment) as the presumptive remedy for MSWLFs.
In 1992, EPA introduced the Superfund Accelerated Cleanup Model (SACM) to accelerate all phases of the remedial process. The
presumptive remedy initiative is one tool for speeding up cleanups within SACM. One way that'presumptive remedies can streamline
the remedial process is through early identification of data collection needs for the remedial design. By collecting design data prior
to issuance of the Record of Decision (ROD), the need for additional field investigations during the remedial design (RD) will be
reduced, thereby accelerating the overall remedial process for these sites. Data needed for design also can be useful in better defining
the scope of the remedy and in improving the accuracy of the cost estimate in the ROD. Since containment is the presumptive remedy
for MSWLFs, the Remedial Project Manager (RPM) can begin making arrangements to collect landfill cap design data as soon as a
basis for remedial action is established (e.g., ground water contaminant concentrations exceeding maximum contaminant levels
[MCLs]).
This fact sheet identifies the data pertinent to landfill cap design that will be required for most sites. These data are organized within
six categories: (1) waste area delineation; (2) slope stability and settlement; (3) gas generation/migration; (4) existing cover assessment;
(5) surface water run-on/run-off management; and (6) clay sources. For reference, all data requirements and data collection methods
discussed in this document are summarized in a table at the end of this document (Table 2). In addition to the following guidance
provided in this fact sheet, RPMs should enlist the aid of technical experts familiar with landfill cap design in establishing data
collection needs for specific sites.
TECHNICAL AREA 1: WASTE AREA DELINEATION
The area of a landfill cap is determined by the horizontal extent of previous waste disposal. One of the major causes of cost escalation
for MSWLF sites has been the failure to establish the actual boundaries of the waste. Costly construction change orders have been
required to increase the area of the cap because wastes have been found to extend well beyond the edges of the intended cap. Waste
boundaries should be identified as accurately as practicable prior to initiation of the design.
Aerial photographs, maps, and a local newspaper subject
search may provide a historical record of the extent and type
of disposal activities conducted at the site. If appropriate,
residents could be interviewed to confirm or supplement
available information.
Field investigation should be used to confirm records and to
collect data to delineate the outer boundaries of the waste.
Field investigations normally include surface, subsurface, and
noninvasive geophysical explorations. Field investigation
methods that provide information on the surface and shallow
subsurface extent of waste include excavating shallow test pits,
using direct-push exploration techniques, and drilling bore-
holes. Additional subsurface investigation methods are used to
provide information on the vertical extent of waste.
Borings can be used to estimate waste thickness and condition
of existing cover soils adjacent to or underlying the waste.
-------
However, drilling into or through the waste and into the
underlying soils and/or bedrock should be performed only if
necessary, and only if the driller is experienced in the methods
used to prevent cross-contamination. Additional health and
safety concerns (especially exposure to methane gas) must be
addressed in the health and safety plan when borings are
located in the waste.
Visual evidence of the waste boundary or subsurface contami-
nation from these field investigation activities should be
recorded and, if necessary, verification samples should be
collected and shipped for laboratory analyses.
Surface geophysical methods also may be useful in delineating
the waste boundary. Each method has limitations, and the
selection of an appropriate method should be based on landfill
characteristics and data needs. The most commonly employed
geophysical methods include:
i
• Magnetometry (measures minor changes in earth's mag-
netic field)—location of waste boundary and distribution of
metallic waste
• Electromagnetic Conductivity (response to artificially
induced magnetic field)—location of areas of contrasting
conductivity, such as a landfill or natural deposits
• Ground-Penetrating Radar (reflection of electromagnetic
waves)—determination of horizontal extent and depth of
disturbed soils and buried objects (often used to confirm
magnetometry)
• Electrical Resistivity (measures earth's response to
electrical current)—determination of edge of landfill by
subsurface resistivity difference
• Seismic Refraction (natural or induced compression
waves)—estimation of depth to geologic strata and bedrock
adjacent to the landfill.
These noninvasive surface geophysical methods should be
performed prior to invasive explorations (e.g., borings or test
pits). This will allow for the more limited intrusion activities
to verify the findings of the noninvasive exploration methods.
TECHNICAL AREA 2: SLOPE STABILITY AND SETTLEMENT
Waste settlement and/or slope failure of the waste and existing cover soils can occur during construction of, or after completion of,
the cap. Waste settlement or slope failure (see Figure I) may expose waste and require costly repairs. Data are needed on degree
of slope, existing cover materials, and existing cover soils to create cross-sectional diagrams for use in evaluating landfill slope
stability and the potential for settlement damage.
stability problems such as slippage failures in the waste and/or
existing cover soil. Differential settlement occurs when one
area of waste settles more readily than another because of
differences in moisture content, waste compaction, or waste
composition. Settlement (magnitudes typically range from 5
to 25 percent of the initial waste thickness), and especially
differential settlement, may create cracks in the cap and allow
rainwater to reach the waste. Changes in the topography of the
landfill because of settlement may also create areas on the cap
surface where rainwater can pond.
In creating the conceptual landfill cap design, three separate
calculations are conducted:
• Stability of waste—largely depends on how well the waste
was compacted when placed, waste layer thicknesses, and
waste composition
• Stability of the cap (existing and proposed)
• Settlement of waste—largely depends on how well the
waste was compacted when placed, waste layer thicknesses,
age, rate of waste degradation, and waste composition.
Because of their heterogeneous nature, the settlement and
stability of municipal wastes are difficult to predict. Settle-
ment rates of selected areas of the waste can be measured by
placing survey monuments on top of the waste and taking
periodic measurements to determine the change in elevation of
Figure 1. Typical slope failure at MSWLF site.
Settlement in a landfill can be caused by factors such as:
biodcgradation of wastes, consolidation of waste under the
weight of waste material and cap, deterioration of partially
filled containers (e.g., drums), or compaction of material
during landfill operation or cap installations. Possible
consequences of settlement include instability in the waste or
cover soil, which can damage the cap. In fact, a recent article
on cap design reports that "The center of a 20-foot diameter
section of a landfill cover, for instance, could settle only 0.5 to
1.5 feet before significant cracking [of the composite clay
liner] could be expected." (Koemer and Daniel, 1992) For
this reason, settlement potential and stability of the landfill
system should be evaluated concurrently.
The weight of the new cap can be significant enough to cause
additional waste settlement and compaction. The effect of this
additional weight may initiate differential settlement across the
cap, thus compromising the integrity of the cap, or create
-------
the monuments. Because settlement generally otcurs slowly,
it is important to begin measurement early, preferably during
the remedial investigation. •• .
The settlement of the waste depends on thickness and general
composition of the waste and existing topography. Compress-
ibility characteristics are derived from preload tests and
empirical correlations to data in the published literature. Data
from surveying monuments, settlement plates, and topographic
surveys can be used to determine surface settlement rates
across the landfill.
The stability of waste can be determined by evaluating the
following:
• Potentiometric surface and perched water table informa-
tion—can be determined using water level measurements
from piezometers and monitoring wells
• Thickness of waste
• Existing topography—can be determined from site
reconnaissance and topographic surveys.
Ground motions induced by earthquakes (seismic events) can
also affect cap performance through a decrease in slope sta-
bility. This fact sheet does not address the additional data
required for cap designs for landfills located in seismic impact
zones.
The waste thickness and composition can be determined by
observing and sampling (during completion of test pits,
borings, and hand-augered holes with an experienced driller)
and by searching through historical records.
The existing cover soil should also be evaluated to determine
its stability and potential for settlement. Studies for the
stability of the existing cover soil could include:
• Maximum slope
• Soil classification
• Potentiometric surface
• Shear strength
• Thickness
• Density.
Slope measurements and potentiometric surface derivations can
be obtained using the same procedures used to determine waste
characteristics. The remaining data can be obtained by boring
piezocone penetrometer (PCPT), geophysical techniques, and
test pits. Existing cover soils should be classified by grain size
and hydrometer analysis, as well as by Atterberg limits
performed on borings and test pit samples. See the summary
table at the end of this fact sheet (Table 2) for recommended
tests to determine the shear strength for fine- and coarse-
grained soils.
The stability and settlement estimates for existing cover soil
depend largely on the complexity of the landfill site.
Investigations necessary to evaluate physical properties of the
existing cover soils will depend on the type(s) of soils
encountered. If the existing cover soils are soft silts and clays
the settlement and stability evaluations will be more complex
than for sands and gravels'. These soil samples should be
collected during drilling of monitoring wells to save time and
money, usually during the remedial investigation (RI).
Additional slope stability evaluations will be performed during
landfill cap design. Slopes greater than 3:1 (3 horizontal/
1 vertical) and landfills that have been constructed within or
adjacent to wetlands or low-strength soils are of particular
concern. These areas of concern should be identified during
RI/FS data collection to the extent possible.
TECHNICAL AREA 3: GAS GENERATION/MIGRATION
Volatile
Damage to Emissions
Vegetation
Figure 2. Vertical and lateral migration of
generated gas from MSWLF site.
Generation of gas typically results from the biological
decomposition of organic material in the wastes. The rate and
process of gas generation are dependent on the availability of
moisture, temperature, organic content of the waste, waste
particle size, and waste compaction.
Data immediately available in the field for assessing gas
generation are landfill gas composition and gas pressure Gas
composition in soils usually is evaluated in the field by
monitoring or sampling through gas probes using a methane
meter, explosimeter, or organic vapor analyzer. Air samples
should be analyzed for the presence of volatile organic
compounds (VOCs) or semivolatile organic compounds
-------
(SVOCs). Moisture and heat content also can be determined
by the laboratory or in the field with hand-held instruments.
This information may be necessary to assess possible treatment
alternatives for collected gas.
Gas migration is a function of site geology, chemical
concentration, and pressure and density gradients. Gases
migrate through the path of least resistance (e.g., coarse and
porous soils, bedding stone along nearby water and sewer
lines). Data for evaluating gas migration control arid treatment
methods include the composition of any existing landfill liners,
soil stratigraphy, depth to water table, proximity of human/
ecological receptors, and the locations of buried utilities and
other backfilled excavations and structures.
Gas migration pathways may be identified based on knowledge
of the site geology, hydrogeology, and surrounding soil charac-
teristics and by review of water and sewer maps. Some of
these data may be obtained by collecting and evaluating
samples from test pits, borings, or hand-augered holes.
Piczocone data also may be cost-effective for characterizing
the surrounding subsurface soils at larger MSWLF sites.
Potential receptors of landfill gas emissions may be identified
through site reconnaissance, and receptor locations should be
monitored to assess possible accumulation of migrant landfill
gases. Atmospheric monitoring at receptor locations may be
done using a flame ionization detector (FID), a photoionization
detector (PID), or a gas monitoring station; however, a PID
will not detect methane and thus cannot be used to assess
explosion risk. An oxygen meter using the Lower Explosive
Limit (LEL) indicator may be used to detect explosive levels
of gas.
Gas control is accomplished through either passive or active
gas collection. Treatment of collected gas may be required
depending on the concentration of hazardous constituents. The
gas control system required will depend on the proximity of
receptors, permeability of migration pathways, State and
Federal regulations and guidelines, and level and rate of gas
generation. Effective gas disposal methods include flaring,
processing and sale, and/or sorption.
Active gas collection may be necessary to control gas
migration when receptors are, or are expected to be, at risk.
Active gas collection generally is required when measurements
exceed either
• 5% methane at the property line or cap edge, or
• 25% methane LEL in/at on-site structures. (This subject is
further addressed in the U.S. EPA Technology Brief: Data
Requirements for Selecting Remedial Action Technology
[U.S. EPA, 1987].)
A gas pumping test can be used to improve the estimate of the
gas permeability of the waste materials and unsaturated soils,
number of collection wells required, piping size and configura-
tion, and blower requirements. However, gas pumping tests
should not be relied on without further measurement and
adjustment during construction.
TECHNICAL AREA 4: EXISTING COVER ASSESSMENT
Existing landfill caps should be evaluated to determine whether or not any components can be reused in the construction of a new
cap. Use of existing components could save both time and money.
Data on existing components can be readily collected because
only materials above the waste need be sampled. Sampling
locations and procedures that will minimize damage to
gcosynthetic materials should be used. Sampling holes should,
at a minimum, be refilled with bentonite if the existing cap is
composed of clay. Geosynthetics should be patched with mate-
rials of equal properties following manufacturer's guidelines.
Additionally, the site reconnaissance should be used to
evaluate, in general, the need for regrading the landfill surface
to achieve proper side slopes. Appropriate limits to the
steepness of slopes can be determined from preliminary slope
stability calculations. Excavation into landfill waste materials
may be required to reduce slope steepness to acceptable limits.
Table 1 provides recommended guidelines for final cover
designs. The assessment of the existing cover should include
an evaluation of the potential for any components to meet final
cover guidelines.
Table 1. Existing Cover Assessment Data
Requirements and Recommended Guidelines
Data
Requirements
Recommended Guidelines0
(for Final Cover)
Slope (top) 3% to 5% minimum for drainage
Cap Area Covers horizontal waste limits
Vegetative/Soil Vegetative soil supporting healthy low
Layer shrubs or grass, no erosion, gullies or
deep-rooted plants, no unacceptable frost
heaves or settlement
Drainage Layer Permeability >1x10'2 cm/s (sand, gravel,
or geosynthetic)
Barrier Layer Two-component (geomembrane atop
compacted clayb) composite liner below
the frost zone
Gas Venting Either passive vents located at high points
System (not clogged, no settlement) or extraction
and treatment system working properly
a Refer to EPA's Technical Guidance Document: Final Covers on
Hazardous Waste Landfills and Surface Impoundments (U.S. EPA,
1989).
b Clay compacted to a permeability <_ 1x10'7 cm/s, geomembrane
thickness > 20 mil.
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TECHNICAL AREA 5: SURFACE WATER RUN-ON/RUN-OFF MANAGEMENT
The surface area and gradient of landfill slopes will affect surface water control measures. For the protection of both the landfill cap
and adjacent areas (see Figure 3), the design of the final remedy should ensure that the site layout will provide adequate space for
surface water diversion and containment/retention impoundments.
Storm Run-off
Overflows
Containment
Impoundment
Silt-laden Water
Impacts Stream
Figure 3. Storm run-off impact from
an MSWLF site.
RCRA Subtitle D minimum requirements for MSWLFs (40
CFR Section 258.26) include providing a run-on control system
capable of preventing flow onto the active portion of a landfill
during the peak discharge from a 25-year rain storm. The
regulation also requires providing run-off control systems to
collect, at a minimum, the water volume resulting from a
24-hour, 25-year rainstorm. RCRA Subtitle D regulations
apply to the closure of active MSWLFs and may be Applicable
or Relevant and Appropriate Requirements (ARARs) for cer-
tain landfills at CERCLA sites as well.
The method for estimating run-on and run-off design
discharges should be based on engineering judgment and
on-site conditions (e.g., the Rational Method used by
hydrologists to determine overland flow). Detailed storm flow
calculations usually are done during the design phase. How-
ever, data for preliminary calculations should be collected early
enough to prepare an estimate of the cost of run-on/run-off
control measures as part of the remedy estimate for the ROD.
Because run-on and run-off control is required for operating
landfills, some landfills may already have surface water
diversion or containment impoundments that allow sediment
TECHNICAL AREA 6: CLAY SOURCES
to settle out of the run-off and that control discharge for a
25-year storm. Depending on when the landfill was designed
(with respect to applicable Federal and State regulations),
existing control structures may not have adequate capacity. In
addition, the RI/FS should identify areas for temporary surface
water controls for use during cap construction activities.
A review of the original design or site records available for a
landfill may provide information on design criteria for the
surface water control structures. Site reconnaissance should be
conducted to evaluate the physical condition of the system. If
there are no existing diversion or containment impoundments,
adequate space should be located on or off site to accommo-
date them. Property acquisition may be necessary if on-site
space is not available.
Prior to cap installation, collected or diverted run-on surface
waters often can be discharged to a nearby surface waterbody
or to a recharge basin. Discharge to surface water is
considered a point source discharge and must comply with the
National Pollution Discharge Elimination System (NPDES)
requirements of the Clean Water Act. Because many States
have jurisdiction for the discharge of pollutants to surface
waters, permit requirements may vary depending on location,
although an NPDES permit is always needed. Other factors to
consider are the water quality and soil type, which can be
determined by analysis of surface water samples, visual and
sieve analyses of the soil, and review of NPDES compliance
data (if applicable).
After the cover is installed, the collected or diverted surface
water is not contaminated; therefore, diversion or containment
impoundment maintenance usually is limited to control of
vegetation and debris and sediment removal. Discharge to a
recharge basin is not considered a point source discharge and,
generally, regulators evaluate these basins for permit compli-
ance on a case-by-case basis.
A compacted clay layer is normally one of the primary components of an effective cap, provided that sources of clay (low-permeability
soil) are available at or near the landfill. Data-gathering activities should include looking for potential on-site/local clay deposits
for the cap construction. Manufactured geosynthetic clay liners should be considered if the required volume or physical properties
are not available in nearby soils. A comparison of geosynthetic clay liner material cost versus clay excavation and transport cost
should be completed before design commences.
Investigation of potential sources for clay should be initiated
prior to the preliminary conceptual cap design (which defines
the components of the cover). For information on clay
deposits, the Soil Conservation Service (SCS) of the U.S.
Department of Agriculture (USDA) publishes soil maps and
classifications by county. Additional information on the
availability of clay soils may be obtained from State natural
resource inventory programs; local contractors or engineering
firms practicing in the area; State and local highway officials,
-------
shallow borings, lest pits, and hand-augercd holes; and
gcotcchnical laboratory testing.
After potential sources of clay are identified, a site recon-
naissance may be conducted. The site reconnaissance should
include sample collection via hand-augered holes or shovels to
verify the availability of clay over the site.
Subsurface soil samples of the source area should be collected
later to determine resource quality (shear testing of layer
interfaces) and quantity. Procedures used to characterize clay
sources generally include:
• Excavation of at least one test pit for every 25.000 to
50,000 cubic yards
• Collection of soil samples from test pits for laboratory
characterization
• Shallow borings to confirm soil type, volume, and, in
certain instances, depth to ground water
• Laboratory testing of samples collected including: grain
size analysis, Atterberg limits, permeability testing,
moisture content, and compaction testing. Detailed
compaction requirements to meet construction quality
assurance objectives are provided in Quality Assurance and
Quality Control for Waste Containment Facilities (U.S.
EPA, 1993b).
If sufficient quantities of soil cover materials with appropriate
engineering properties are not available within an economically
practicable distance from the project site, geosynthctics or
processed natural materials should he considered. Geosynthetic
clay liners are generally manufactured by cither sandwiching
bentonitic clays between geotextiles or affixing the bentonitic
clay to the bottom surface of a membrane. Thus, if clay is not :
readily available, low-permeability layers of the cap may be
comprised of either available soil that is processed by adding
bentonite to reduce the permeability or geosynthetic clay liners.
For cap drainage layers, geosynthetic drainage nets may also
be used, in lieu of coarse sand and gravel, to meet performance
requirements. Information on geosynthetic clay liners and
drainage nets can be obtained from manufacturer catalogues.
CONCLUSION
For each MSWLF site where capping is clearly a preferred
remedy, the RPM should assemble a technical review team to
determine the design data to be collected. This team should
include experienced RPMs and technical experts familiar with
data collection nee^s for cap design. The team can help the
RPM in defining the field work required and its timing and in
reviewing the design data submitted by the contractor. In the
event that the contractor is changed (i.e., the RI/FS is Fund-led
and the design is switched to Potentially Responsible Party
[PRPJ-led), the technical review team can assist the RPM in
transferring the pertinent collected design data to the new
contractor.
Table 2 summarizes the data needs and collection methods
presented in this fact sheet. This table should be used as a
reference when determining necessary design data collection
activities.
Table 2. Data Requirements and Coitectlon Methods
Data Requirements
Waste Area Delineation
Design/historical information
Horizontal extent of waste
Depth and thickness of waste
Slope Stability and Settlement*
Waste Evaluation
Slope measurement (A)
Potentiometric surface (A)
Compressibility characteristics (C)
Settlement rate (C)
Thickness of waste (A.C)
General waste composition (A,C)
Existing topography (A.C)
Collection Methods
Historical records, personal interviews
Test pits, probes, hand-augered holes, magnetometry, electromagnetic
conductivity, ground-penetrating radar, electrical resistivity, seismic refraction
Borings, geophysical surveys ________,-
Slope inclinometers, topographic survey
Piezometers/monitoring wells
Preload testing, empirical correlations to published literature
Survey monuments, settlement plates, topographic survey
Observation and sampling during test pits, borings, hand-augered holes, historical
records, geophysical surveys
Observation and sampling during test pits, borings, hand-augered holes, historical
records, geophysical surveys
Site reconnaissance, topographic survey, historical photographs
(continued)
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Table 2 (continued)
Data Requirements
Data Collection Methods
Existing Cover Soil Evaluation8
Slope measurement (A,B)
Soil classification (B)
Potentiometric surface (A,C)
Shear strength (B)
Compressibility characteristics (C)
Density (B)
Topographic survey, slope inclinometers
Grain size analysis, hydrometer analysis, Atterberg limits performed on
borings/test pit samples
Piezometers/monitoring wells
Fine-grained soil (cohesion): Field and/or lab vane shear test, torvane, pocket
penetrometer, piezocone penetrometer, unconfined compressive strength,
empirical correlations to Standard Penetration Test (S-P-T)
Coarse grained soil (friction angle): Empirical correlations to S-P-T, direct shear
test, triaxial shear test, piezocone penetrometer
Consolidation tests performed on undisturbed tube samples collected from
borings. Empirical correlations to index properties (water content, plasticity).
Empirical correlations to S-P-T data, bulk density determination from undisturbed
tube samples (fine-grained soils only)
Gas Generation/Migration
Gas composition and gas pressure
Moisture and heat content
Migration pathways
Receptors
Gas probes, monitoring wells, laboratory samples
Laboratory samples or handheld instruments in the field
Water and sewer maps, piezocone, test pits, borings, hand-augered holes
Site reconnaissance, photoionization detector, flame ionization detector, air
monitoring station, oxygen meter
Existing Cover Assessment
Slope-top
Cap area
Vegetative/soil layer
Drainage layer
Barrier layer
Gas venting system
Site reconnaissance, topographic survey
Site reconnaissance, borings, test pits, geophysical survey
Site reconnaissance, topographic survey, test pits
Site reconnaissance, borings, test pits, hand-augered holes, field infiltrometer or
laboratory samples for hydraulic conductivity
Test pits, borings, hand-augered holes, Shelby tubes for permeability, laboratory
samples/analysis for shear strength, compaction curve, Atterberg limits,
freeze/thaw cycling, water content
Site reconnaissance, gas character sampling, gas pumping tests
Run-on/Run-off Management
Estimated discharge, size of control
structures, treatment requirements
Climatic data
Run-on/run-off areas
(% vegetated, % paved)
Water quality
Soil types
Review of design records, National Pollutant Discharge Elimination System
(NPDES) permit, detailed storm flow calculations
National Oceanographic and Atmospheric Administration (NOAA)
Site reconnaissance, topographic surveys, aerial photographs
Surface water sampling and analysis
Visual, aerial photographs, and soil maps from the Soil Conservation Service
(SCS)
Clay Sources
Soil properties
Subsurface resource adequacy and
quantity (shear testing)
Geosynthetic clay liner properties
Soil maps from the SCS, local contractors or engineering firms, state/local
transportation officials, natural resource inventory programs, shallow borings,
hand-augered holes, test pits, and geotechnical laboratory testing
Grain size analysis, Atterberg limits, permeability test, moisture content,
compaction test, shallow borings, test pits, laboratory testing
Manufacturer catalogs, literature, EPA studies/guidance
The letters following the slope stability and settlement and existing cover soil evaluation data requirements are referenced to the data needed to
perform the three separate calculations used to evaluate slope stability and settlement of the landfill cover (see Technical Area 2):
A = Stability of waste.
B = Stability of cap components.
C = Settlement of waste.
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BIBLIOGRAPHY
»
Koerner, R., and Daniel, D.
Engineering, May:55-57.
1992. Better cover-ups. Civil
U.S. Army Corps of Engineers (Moses, D.). 1993. Checklist
for Landfill Cover Design. Draft. May.
U.S. EPA (Environmental Protection Agency). 1985. Covers
for Uncontrolled Hazardous Waste Sites. EPA/540/2-
85/002.
U.S. EPA (Environmental Protection Agency). 1987. Data
Requirements for Selecting Remedial Action Technology.
EPA/600/2-87/001.
U.S. EPA (Environmental Protection Agency). 1989.
Technical Guidance Document: Final Covers on
Hazardous Waste Landfills and Surface Impoundments.
EPA/530/SW-89/047. July.
U.S. EPA (Environmental Protection Agency). 1991.
Conducting Remedial Investigations/Feasibility Studies for
CERCLA Municipal Landfill Sites. EPA/540/P-1/001.
Office of Emergency and Remedial Response, February.
U.S. EPA (Environmental Protection Agency). 1993a.
Engineering Bulletin: Landfill Covers. EPA/540/S-93/500.
U.S. EPA (Environmental Protection Agency). 1993b.
Technical Guidance Document: Quality Assurance and
Quality Control for Waste Containment Facilities.
EPA/600/R-93/182.
For more information contact:
Kenneth Skahn
Office of Emergency and Remedial Response
(703) 603-8801
or
Supcrfund Hotline
(800) 424-9346
NOTICE: This fact sheet is intended solely for informational purposes and cannot be relied upon to create any rights enforceable
by any party in litigation with the United States.
&EPA
United States
Environmental Protection
Agency (5203G)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
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/-*«,.» of Directive: 9200.5-162
United States 2^ Waste and EPA/540/FW5/128
Environment* Protecfon o". PB 95-953410
Wwhbigton. DC 20460 December 1995
_ _ ______ ___
Presumptive Remedies for
Soils, Sediments, and Sludges
at Wood Treater Sites
-------
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EPA/540/R-95/128
December 1995
Presumptive Remedies for
Soils, Sediments, and Sludges
at Wood Treater Sites
Office of Emergency and Remedial Response, 5202G
Washington, DC 20460
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TABLE OF CONTENTS
INTRODUCTION 1
PURPOSE 1
USE OF THIS DOCUMENT 2
ANTICIPATED BENEFITS OF PRESUMPTIVE REMEDIES 2
DESCRIPTION OF WOOD TREATER SITES 4
PRESUMPTIVE REMEDIES FOR WOOD TREATER SITES 6
Bioremediation . 6
Thermal Desorption . 7
Incineration 7
Immobilization 8
PRESUMPTIVE REMEDY PROCESS FOR WOOD TREATER SITES 8
CONCLUSION . 15
GLOSSARY 49
REFERENCES 51
APPENDIX A: TECHNICAL BASIS FOR PRESUMPTIVE REMEDIES 31
APPENDIX B: EVALUATION OF SELECTION CRITERIA FOR
TECHNOLOGIES USED TO TREAT CONTAMINATED
SOILS, SEDIMENTS, AND SLUDGES AT WOOD
TREATER SITES . 41
Page iii
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LIST OF TABLES
TABLE 1: Evaluation of Presumptive Remedy Technology Options 11
TABLE 2: Comparison of Presumptive Remedy Technologies 20
TABLE 3-A: Data Requirements for Bioremediation 26
TABLE 3-B: Data Requirements for Thermal Desorption 28
TABLE 3-C: Data Requirements for Incineration 29
TABLE 3-D: Data Requirements for Immobilization '30
TABLE A-1: Remedies Selected at NPL Wood Treater Sites '.'.'.'.'. 32
TABLE A-2: Summary of Initial Screening Phase For Wood Treater Sites '.'.'.'.'.'.'. 34
TABLE A-3: Summary of Detailed Analysis Phase For Wood Treater Sites ............ 37
LIST OF BOXES
BOX A: Ground-Water Considerations 3
BOX B: Contacts for Additional Information 4
BOX C: Contaminants Commonly Found at Wood Treater Sites '.'.'.'.'.'.'.'.'.'.'. 5
BOX D: Background Information on NAPL Contamination ........... 16
BOX E: Practical Considerations ! 18
LIST OF FIGURES
FIGURE 1: Decision Tree for Technology Selection at Wood Treater Sites 9
FIGURE D-1: Components of DNAPL Sites , ! 17
FIGURE D-2: Types of DNAPL Contamination and Contaminant Zones at DNAPL Sites
(Cross-Sectional View) , 17
Page iv
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INTRODUCTION
Since the enactment of the Comprehensive
Environmental Response, Compensation, and Liability
Act of 1980 (CERCLA or Superfund), the Superfund
remedial and removal programs have found that certain
categories of sites have similar characteristics, such as
types of contaminants present, disposal practices
performed, or environmental media affected. Based on
information acquired from evaluating and cleaning up
these sites, the Superfund program is undertaking an
initiative to develop presumptive remedies to accelerate
future cleanups at these types of sites. The
presumptive remedy approach is one tool for speeding
up cleanups within the Superfund Accelerated Cleanup
Model (SACM). This approach can also be used to
streamline remedial decisionmaking for corrective
actions conducted under the Resource Conservation
and Recovery Act (RCRA).
Presumptive remedies are preferred technologies for
common categories of sites, based on EPA's experience
and its scientific and engineering evaluation of
alternative technologies. The objective of the
presumptive remedies initiative is to use the Superfund
program's experience to streamline site characterization
and speed up the selection of cleanup actions. Over
time, presumptive remedies are expected to ensure
consistency in remedy selection and reduce the cost and
time required to clean up similar types of sites.
Presumptive remedies are expected to be used at all
appropriate sites except under unusual site-specific
circumstances.
This directive identifies the presumptive remedies for
wood treater sites with contaminated soils, sediments,
and sludges. EPA has developed guidance on
presumptive remedies for municipal landfill sites [33]
and sites with volatile organic compounds (VOCs) in
soils [32]. EPA is also in the process of developing
guidance on presumptive remedies for polychlorinated
biphenyl (PCB), grain storage, manufactured gas plant,
and contaminated ground-water sites. In addition,
EPA has developed a directive entitled Presumptive
Remedies: Policy and Procedures [31], which outlines
and addresses the issues common to all presumptive
remedies (e.g., the role of innovative treatment
technologies).
Bold and italicized terms are defined in the Glossary at
the end of this document. The References section at
the end of this document provides a list of supporting
guidance documents that may be consulted for
additional information on relevant topics. Bracketed
numbers [#] appear throughout the text to indicate
specific references in the References section.
PURPOSE
The purpose of this directive is to provide guidance on
selecting a presumptive remedy or combination of
presumptive remedies for wood treater sites with
contaminated soils, sediments, and sludges.
Specifically, this guidance:
• Describes the contaminants generally found at
wood treater sites;
• Presents the presumptive remedies for
contaminated soils, sediments, and sludges at
wood treater sites;
• Describes the presumptive remedy process
concerning the site characterization and
technology screening steps; and
Outlines the data that should be used to select a
presumptive remedy.
The presumptive remedies for wood treater sites with
soils, sediments, and sludges contaminated with organic
contaminants are bioremediation, thermal desorption.
and incineration. The presumptive remedy for wood
treater sites with soils, sediments, and sludges
contaminated with inorganic contaminants is
immobilization. The section of this document entitled
"Presumptive Remedies for Wood Treater Sites"
provides a brief description of each of these
technologies.
The decision to establish these technologies as
presumptive remedies for this site type is based on
EPA's accumulated knowledge about site
characterization and remedy selection for wood treater
sites with contaminated soils, sediments, and sludges,
including actual performance at Superfund and RCRA
sites. This decision is also based on an analysis
conducted by EPA on Feasibility Studies (FSs) and
Records of Decision (RODs) for sites where wood
treating contaminants in soils, sediments, and sludges
drove remedy selection. The results of this analysis,
which are summarized in Appendix A (Technical Basis
for Presumptive Remedies), demonstrate that these
four technologies represent approximately 84% of the
remedies selected in the FSs and RODs analyzed. The
FS/ROD analysis also provides information on why
other, non-presumptive technologies generally are not
effective and/or appropriate for cleaning up wood
Pagel
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treater sites with contaminated soils, sediments, or
sludges.
USE OF THIS DOCUMENT
This directive is designed to assist Superfund site
managers (i.e., Remedial Project Managers (RPMs) and
On-Scene Coordinators (OSCs)) and other personnel in
selecting remedies for cleaning up soils, sediments, and
sludges at wood treater sites that are contaminated
primarily with creosote, pentachlorophenol. and/or
chromated copper arsenate. Site managers in other
programs, such as the RCRA corrective action program
or the private sector, may also find this document
useful. For example, the information contained in this
document could be used to eliminate the need for an
alternatives screening step and streamline the detailed
analysis of alternatives in the RCRA Corrective
Measures Study, which is analogous to the FS under
CERCLA.
Wood treater sites that have contaminated soils,
sediments, and sludges often have contaminated ground
water as well. At some of these sites, the contaminated
soils, sediments, or sludges may not require treatment
or may only need to be contained, depending on the
degree of human health and environmental risk posed
by the contaminated soils, sediments, or sludges as
determined in the removal site evaluation and/or
remedial site evaluation (i.e., the preliminary
assessment/site inspection (PA/SI)). At some sites, a
combination of treatment options may need to be
implemented to address the contamination of ground
water as well as soils, sediments, and sludges. When
addressing contamination at wood treater sites, site
managers should consider the impact of contamination
across all environmental media. In particular, site
managers at wood treater sites should consider the
impacts of ground-water contamination. EPA is
currently developing guidance on a presumptive remedy
approach for responding to contaminated ground-water
sites. When available, this guidance should be used to
address ground-water contamination at wood treater
sites. Site managers should also consult existing
guidance on the remediation of contaminated ground
water [6, 7, 17, 20, 38]. Box A provides a brief
discussion of ground-water considerations for wood
treater sites that is consistent with existing guidance
and the forthcoming presumptive remedy ground-water
approach. In addition, Box D provides background
information on non-aqueous phase liquid (NAPL)
contaminants, including dense NAPLs (DNAPLs or
sinkers) and light NAPLs (LNAPLs or floaters).
The presumptive remedy evaluation and selection
process described in this document is consistent with
and fits into the more detailed conventional remedy
selection process outlined in the National Oil and
Hazardous Substances Pollution Contingency Plan
(NCP, 40 CFR Part 300). The Agency believes that
the presumptive remedies set out in this document
represent appropriate response action alternatives for
sites meeting certain criteria and, therefore, generally
should be used. However, remedy selection for an
individual site may vary because of specific site
characteristics or community or state concerns.
Although it may still be possible to accelerate remedy
selection for non-presumptive technologies, such
selection will not be able to take advantage of the
generic justification provided by this document. Under
these circumstances, a conventional Remedial
Investigation/Feasibility Study (M/FS) or Engineering
Evaluation/Cost Anafysis (EE/CA) should be performed.
Guidance on circumstances in which a presumptive
remedy might not be appropriate is found in
Presumptive Remedies: Policy and Procedures [31].
When determining whether a remedial or removal
action is the appropriate method for cleaning up a
wood treater site, site managers should consult the
NCP and Superfund program guidance. Also, the
Agency is currently developing a fact sheet to assist
RPMs and OSCs in identifying the factors affecting the
site-specific determination of whether a Superfund
early action is best accomplished as a non-time-critical
removal action or an early remedial action.
This directive is not a stand-alone document. To
ensure a full understanding of wood treater site
characterization and remedy selection, site managers
should refer to the FS/ROD analysis, which is
summarized in Appendix A of this document, and the
documents cited as references at the end of this
document. Site managers unfamiliar with certain
complex site conditions at wood treater sites should
consult with experienced site managers, the contacts
listed in Box B of this document, the Superfund
Technical Assistance Response Team (START), or the
Environmental Response Team (ERT). EPA is
continuing to gather and develop more information on
the remedies selected and implemented at wood treater
sites.
ANTICIPATED BENEFITS OF
PRESUMPTIVE REMEDIES
The use of this document is expected to reduce the
costs and time required for remedy selection at wood
treater sites. This directive should be used to:
Page 2
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BOX A
Ground-Water Considerations
Wood treater sites typically involve subsurface DNAPL and/or LNAPL contaminants (see Boxes C and D) in
addition to contaminated soils, sediments, or sludges. All of these materials are sources of contamination of the
underlying ground water and need to be considered when planning an overall site response. A key element of
all existing ground-water remediation guidance is that site characterization and response actions should be
implemented in a phased approach. In a phased approach, site response activities are conducted in a sequence
of steps, such that information obtained from earlier steps is used to refine subsequent investigations, objectives,
or actions. The recommended strategy for sites with NAPL contamination, such as wood treater sites, includes
the following response actions and objectives [17].
Site investigations should be designed to delineate both NAPL zones and aqueous plumes. NAPL zones are
those portions of the site where LNAPL or DNAPL contaminants (in the form of immiscible liquids) are
suspected in the subsurface, either above, at, or below the water table. Aqueous plumes are portions of the site
where contaminants are present in solution and not as immiscible liquids.
Early actions should be used to:
• Prevent exposure, both current and future, to ground-water contaminants;
• Prevent the further spread of the aqueous plume (plume containment);
• Control the further migration of contaminants to ground water from contaminated soils and
subsurface NAPLs, where practicable (source containment); and
• Reduce the quantity of source material present in the subsurface (free-phase DNAPL), to the extent
practicable (source removal/treatment).
Lonft-term remedial actions should be used to:
• Attain those objectives listed above that were not accomplished as early actions;
Minimize further release of contaminants from soils and subsurface NAPLs to the surrounding
ground water (source containment);
Reduce the quantity of source material present in the NAPL zone (free- and residual-phase), to the
extent practicable (source removal/treatment); and
Restore as much of the aqueous plume as possible to cleanup levels (e.g., drinking water standards)
appropriate for its beneficial uses. These beneficial uses should take into account anticipated future
land use(s) (aquifer restoration).
For more information on NAPL contamination, see Box D.
1.
Identify the presumed or likely remedy options up
front and allow for a more focused collection of
data on the extent of contamination.
This presumptive remedy guidance allows for the
evaluation of only the primary cleanup alternative
or a narrow range of options. The judgment as to
whether evaluation of only the primary remedy is
appropriate will depend on the degree of
complexity and uncertainty at a site. Also, it may
be appropriate to collect certain remedial design
data before the drafting of the ROD or Action
Memorandum, thereby allowing the action to
proceed more quickly after signature of the
decision document.
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BOXB
Contacts for Additional Information
Headquarters Policy Contacts:
Frank Avvisato, Wood Treater
Project Manager (703) 603-8949
Scott Fredericks, Presumptive Remedies
Team Leader • (703) 603-8771
Technical Contacts:
Harry Allen, Environmental Response
Team (908)321-6747
Frank Freestone, Office of Research
and Development (908) 321-6632
Regional Contacts:
I Mike Nalipinski
II Mel Hauptman
III Paul Leonard
IV Felicia Barnett
V Dion Novak
VI Cathy Gilmore
VII Diana Engeman
VIII Victor Ketellapper
IX Craig Cooper
X Eric Winiecki
(617) 223-5503
(212) 637-3952
(215) 597-3163
(404) 347-7791
(312) 886-4737
(214) 665-6766
(913) 551-7746
(303) 293-1648
(415) 744-2370'
(206) 553-6904
2. Eliminate the need for the initial step of
screening alternatives during the FS or EE/CA.
The NCP (section 300.430(e)(l)) states that the
lead agency shall include an alternatives screening
step when needed [emphasis added] to select a
reasonable number of alternatives for detailed
analysis. The Agency performed an analysis of
FSs and RODs on the potentially available
technologies for soils, sediments, and sludges at
wood treater sites (see Appendix A) and found
that certain technologies are appropriately and
consistently screened out based on the criteria of
effectiveness, implementability, and cost
(consistent with section 300.430(e)(7)). Based on
this analysis, the Agency has determined that the
initial step of identifying and screening
alternatives for FSs and EE/CAs for wood treater
sites may not be necessary on a site-specific basis;
instead, the FS or EE/CA may proceed
immediately from the identification of alternatives
to the detailed analysis, focusing on the
technologies recommended in this directive. This
document and the accompanying FS/ROD analysis
must be included in the Administrative Record to
provide the basis for streamlining the analysis for
wood treater sites in this way.
3. Streamline the detailed analysis phase of the FS
or EE/CA. ' ' •
Once cleanup alternatives pass the initial
screening step, they must be evaluated against the
appropriate criteria defined in the NCP.
Appendix A of this document summarizes the
analysis EPA conducted on FSs/RODs for wood
treater sites with contaminated soils', sediments, or
sludges, and Appendix B provides generic
evaluations of the different presumptive remedies
against seven of the nine remedial criteria
(excluding state and community acceptance).
Both of these appendices should be used to
streamline the detailed analysis phase of the FS.
Appendices A and B can also be used to
streamline the evaluation of removal action
alternatives in an EE/CA The generic analyses in
Appendix B should be supplemented with site-
specific information for the final response
selection. For a more detailed discussion on
preparing an FS or EE/CA, see the references
listed at the end of this document [16, 19].
EPA expects that at least one of the presumptive
remedies will be suitable for a wood treater site
with principal threats that require the treatment
of contaminated soils, sediments, or sludges.
Circumstances under which other approaches may
be appropriate include: unusual site soil
characteristics; demonstration of significant
advantages of innovative technologies over the
presumptive remedies; and extraordinary
community and state concerns. If such
circumstances are encountered, additional analyses
may be necessary or a conventional RI/FS or
EE/CA may be performed.
DESCRIPTION OF WOOD TREATER
SITES
The wood treating industry has been in existence in the
United States for over 100 years. Wood is usually
treated in cylinders, under pressure, with one or a
combination of the following types of preservatives:
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• Pentachlorophenol (PCP) in petroleum or other
solvents;
• Creosote (in petroleum or other solvents);
• Aqueous solutions of copper, chromium, and
arsenic;
• Copper and arsenic, or copper, arsenic, and zinc
solutions in ammonia; and
• Fire retardants (combinations of phosphates,
borates, boric acid, and/or zinc compounds).
Older facilities traditionally used oil-based
preservatives, while more modern facilities tend to use
water-soluble preservatives. Water-soluble processes
produce little or no wastewater, except for small
amounts of metal-containing sludges. Oil-based
processes produce sludge wastes and significant
quantities of process wastewater. The processes
performed at wood treater sites generally will result in
contaminated soils, sediments, and sludges, and/or
contaminated surface and ground water.
Box C provides a list of contaminants commonly found
at wood treater sites; general chemical categories of
contaminants are provided and specific chemicals or
substances are identified under each category. As
indicated in Box C, most of the organic contaminants
found at wood treater sites are NAPLs, either in their
pure form or as components of other substances that
are NAPLs (e.g., petroleum fuels, creosote). Site
managers should refer to Box D for background
information on NAPLs and cleanup problems
associated with these contaminants.
The three types of contaminants predominantly found
at wood treater sites, either alone or in combination
with each other — or with total petroleum hydrocarbon
(TPH) carrier oils ~ are creosote, PCP, and chromated
copper arsenate (CCA). Creosote is an oily,
translucent brown to black liquid that is a very complex
mixture of organic compounds, containing
approximately 85% polynuclear aromatic hydrocarbons
(PAHs), 10% phenolic compounds, and 5% nitrogen-,
sulfur-, or oxygen-containing heterocycles. PCP is also
an organic contaminant. In its pure form, PCP is a
DNAPL; however, PCP is commonly found at wood
treater sites as an LNAPL mixed into fuel oil or other
BOXC
Contaminants Commonly Found
at Wood Treater Sites
ORGANICS
Dioxms/furans1
• Dibenzo-p-dioxins
• Dibenzofurans
• Furan
Halogenated phenols1
• Pentachlorophenol
• Tetrachlorophenol
Simple non-halogenated aromatics2
• Benzene
• Toluene
• Ethylbenzene
« Xylene
Polynuclear aromatic
hydrocarbons1
2-Methylnaphthalene
Chrysene
Acenaphthene
Fluoranthene
Acenaphthylene
Fluorene
Anthracene
Indeno(l,2,3-cd)pyrene
Benzo(a)anthracene
Naphthalene
Benzo(a)pyrene
Phenanthrene
Benzo(b)fluoranthene
Pyrene
Benzo(k)fluoranthene
Other polar organic compounds
2,4-Dimethylphenolf
2-Methylphenol1
4-Methylphenol1
Benzoicacid1
Di-n-octyl phthalate
N-nitrosodiphenylamine
INORGANICS
Non-volatile metals (compounds
of)
• Chromium
• Copper
Volatile metals (compounds of)
• Arsenic
• Cadmium
• Lead
• Zinc
1 DNAPL(s) in pure form.
2 LNAPL(s) in pure form.
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light organic substances. If PCP or other chlorinated
phenols are present at a site, associated dioxins and/or
furans may also be present in the approximate vicinity.
If so, these dioxins and/or furans will likely exist in
much lower concentrations than the associated
chlorinated phenols. This document is not designed to
address sites containing high levels of dioxins and/or
furans. EPA is currently gathering information on the
issue of dioxin/furan contamination; site managers
should contact the Headquarters policy contacts listed
in Box B for more information on this topic. CCA is
an inorganic arsenical wood preservative. Other metal-
containing preservatives that may be found at wood
treater sites include ammoniacal copper arsenate
(ACA) and ammoniacal copper-zinc arsenate (ACZA).
PRESUMPTIVE REMEDIES FOR WOOD
TREATER SITES
The presumptive remedies for contaminated soils,
sediments, and sludges constituting the principal
threats at wood treater sites are described below.
Bioremediation is the primary presumptive remedy for
treating organic contamination of soils, sediments, and
sludges at wood treater sites. Bioremediation has been
selected as the primary presumptive remedy for treating
organic contamination because it has been selected
most frequently to address organic contamination at
wood treater Superfund sites, and the Agency believes
that it effectively treats wood treating wastes at a
relatively low cost. If bioremediation is not feasible,
thermal desorption may be the more appropriate
response technology. In a limited number of situations
(e.g., the treatment of "hot spots" such as sludges),
incineration may be the more appropriate remedy.
Immobilization is the primary presumptive remedy for
treating inorganic contamination of soils, sediments,
and sludges at wood treater sites.
An important consideration in determining which
presumptive remedy technology is the most appropriate
for a particular site is the future land use or uses
anticipated for that site (see reference [27] and Box E
of this document for more information on land-use
considerations). Another important consideration in
selecting the most appropriate presumptive remedy
technology is determining what are the principal
threats • and low-level threats (including possible
treatment residuals) at a site. Treatment technologies
are the preferred remedies for addressing principal
threats, while containment technologies in conjunction
with institutional and/or engineering controls, are most
likely to be appropriate for addressing low-level
threats. Table 2 (Comparison of Presumptive Remedy
Technologies), which is found at the end of this
document, provides detailed information on the
advantages, limitations, and costs of each of the
presumptive remedies.
At many wood treater sites, it may be necessary to use
a combination of control and treatment options as part
of an overall treatment train to sufficiently reduce
toxicity and immobilize contaminants. Institutipnal
and/or engineering controls can be used in conjunction
with one or more of the presumptive remedy
technologies to enhance the long-term reliability of the
remedy. Site managers should note that all ex situ
remedy options require measures to protect workers
and the community during the excavation, handling,
and treatment of contaminants, and may be subject to
RCRA land disposal restrictions. Box E (Practical
Considerations) provides a discussion of land use,
institutional and engineering controls, treatment trains,
the remediation 6| "hot spots," and land disposal
restriction issues. '
Bioremediation — Bioremediation is the chemical
degradation of organic contaminants using
microorganisms. Biological activity (i.e.,
biodegradation) can occur either in the presence
(aerobic) or absence (anaerobic) of oxygen. Aerobic
biodegradation converts organic contaminants to
various intermediate and final decomposition products,
which may include various daughter compounds,
carbon dioxide, water, humic materials, and microbial
cell matter. Aerobic biodegradation may also cause
binding of the contaminants to soil components, such
as humic materials. Anaerobic biodegradation converts
the contaminants to carbon dioxide, methane, and
microbial cell matter.
Bioremediation may be an ex situ or in situ process. Ex
situ bioremediation refers to the biological treatment
of contaminants following excavation of the soil or
other media, and includes composting, land treatment
in lined treatment cells, treatment in, soil piles, or the
use of soil slurry reactors. In situ bioremediation is the
in-place treatment of contaminants, and may involve
the addition of nutrients, oxygen, or other
enhancements into the subsurface.
EPA has more experience in implementing ex situ
bioremediation than in situ bioremediation. In general,
ex situ bioremediation is faster than /« situ
bioremediation, although the implementation of either
ex situ or in situ bioremediation typically can require
several years, as compared to approximately six months
to a year for technologies like thermal desorption or
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incineration. In situ bioremediation may be less costly
than ex situ bioremediation. However, at some wood
treater sites, ex situ bioremediation may be able to
achieve higher performance efficiencies than the in situ
process due to increased access and contact between
microorganisms, contaminants, nutrients, water, and
electron acceptors.
The effectiveness of bioremediation is site- and
contaminant-specific. Careful contaminant and matrix
characterization (with particular attention to
heterogeneity), coupled with treatability studies of
appropriate scale and duration, are strongly
recommended. Bioremediation can successfully treat
soils, sediments, and sludges contaminated with organic
contaminants, such as halogenated phenols and cresols,
other polar organic compounds, non-halogenated
aromatics, and PAHs. Studies on the bioremediation
of creosote contamination indicate that bioremediation
works well on 2-, 3-, and often 4-ring compounds, but
generally not as well on 5- or 6-ring compounds.
Bioremediation may not be effective for the treatment
of high levels of concentrated residual creosote in soils,
sediments, or sludges. It may be necessary to separate
this material for disposal or treatment by a different
technology (e.g., thermal desorption or incineration)
before attempting bioremediation. The remaining
soils, sediments, or sludges, with lower levels of
contamination, may then be amenable to
bioremediation. Bioremediation generally is not
appropriate for treating inorganic contamination at
wood treater sites. Only limited data on the
bioremediation of dioxins or furans are currently
available; EPA is currently gathering information on
the treatability of dioxins and furans (for more
information, contact the individuals listed in Box B).
Thermal Desorption — Thermal desorption physically
separates, but does not destroy, volatile and some semi-
volatile contaminants from excavated soils, sediments,
and sludges. Significant material handling operations
may be necessary to sort and size the soils, sediments,
or sludges for treatment. Thermal desorption uses heat
or mechanical agitation to volatilize contaminants from
soils, sediments, or sludges into a gas stream;
subsequent treatment must be provided for the
concentrated contaminants resulting from the use of
this technology. Depending on the process selected,
this technology heats contaminated media to varying
temperatures, driving off water and volatile and semi-
volatile contaminants. Off-gases may be condensed for
disposal, captured by carbon adsorption beds, or
treated with biofilters.
Treatability studies are recommended before full
implementation of the thermal desorption technology.
Thermal desorption can successfully treat halogenated
phenols and cresols as well as volatile non-halogenated
organic compounds at wood treater sites. It cannot,
however, effectively separate non-volatile metals (e.g.,
copper) from the contaminated media. Some desorber
units can treat PCBs, pesticides, and dioxins/furans in
contaminated soils, sediments, or sludges.
If chlorine is present in the feed material (e.g., as a
result of PCP), dioxin and furan formation may occur
in the thermal desorber, stack, or air pollution control
devices at temperatures of 350 °F and above. Thermal
treatment systems can be designed and operated to
minimize dioxin and furaji formation and to remove
these compounds from the stack gases. However,
because pilot-scale devices do not always duplicate
operating conditions at full scale, bench- or pilot-scale
treatability studies alone may not be sufficient to verify
dioxin/furan formation or control. A full-scale test,
called a "Proof of Performance" test, with analyses for
dioxins and furans should be completed. Safe thermal
treatment operation should be confirmed prior to the
use of thermal desorption.
Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs) and other laws should be
considered when determining whether thermal
desorption is conducted on- or off-site. On-site
thermal desorption may be performed with a mobile
unit; however, space availability may make this option
infeasible. Thermal desorption may also be conducted
off-site; however, the facilities used must be in
compliance with the Superfund off-site rule before
accepting material from a Superfund site. EPA is
currently in the process of completing guidance that
provides information on the safe implementation of
thermal treatment technologies, including thermal
desorption and incineration.
Incineration — Incineration generally treats organic
contaminants by subjecting them to temperatures
typically greater than 1,000°F in the presence of oxygen
and a flame. During incineration, volatilization and
combustion convert the organic contaminants to carbon
dioxide, water, hydrogen chloride, and sulfur oxides.
The incinerator off-gas requires treatment by an air
pollution control (APC) system to remove particulates
and to neutralize and remove acid gases (e.g., HC1).
This technology may generate three residual streams:
solids from the incinerator and APC system, water
from the APC system, and air emissions from the APC
system.
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Incineration has consistently been demonstrated to
achieve a performance efficiency in the 90 to 99%
range. Incineration has successfully treated wood
treater soil, sediment, and sludge contamination to
cleanup levels that are more stringent than can be
consistently attained by the other wood treater
presumptive remedies. A substantial body of trial burn
results and other quality-assured data verify that
incineration can remove and destroy organic
contaminants (including dioxins and furans) to the
parts per billion or parts per trillion level.
Consequently, incineration may be particularly effective
in treating "hot spots" at wood treater sites.
Incineration, however, does not destroy metals. Metals
will produce different residuals depending on the
volatility of the compounds, the presence of certain
compounds (e.g., chlorine), and the incinerator
operating conditions. Improperly operated incinerators
also have the potential to create dioxins and furans.
Incineration of large volumes of contaminated media
may be prohibitively costly. .
Incineration may be performed on- or off-site. There
may be significant considerations regarding the
compliance of incineration with ARARs and other
laws. On-site incineration may be performed with a
transportable incineration unit; however, space
availability and public opposition may make this option
inappropriate. Whenever incineration is considered as
an option to fulfill remediation goals, particular efforts
should be made to provide the community with good
information on incineration and to be responsive to
any concerns raised by the community. Commercial
incineration facilities (i.e., units permitted for the
incineration of hazardous wastes, including incinerators
and cement kilns) may be used when off-site
incineration is desirable. However, only a limited
number of these facilities are available nationwide.
Permitting of additional on- and off-site incineration
facilities will be affected by EPA's Strategy for
Hazardous Waste Minimization and Combustion [37].
Immobilization— Immobilization reduces the mobility
of a contaminant, either by physically restricting its
contact with a mobile phase (solidification) or by
chemically altering/binding the contaminant
(stabilization). The most common solidification
binders are cementacious materials, including Portland
cement, fly ash/lime, and fly ash/kiln dust. These
agents form a solid, resistant, aluminosilicate matrix
that can occlude waste particles, bind various
contaminants, and reduce the permeability of the
waste/binder mass. Immobilization is particularly
suited to addressing inorganic (e.g., CCA)
contamination.
At wood treater sites, inorganic contamination is
sometimes commingled with organic contamination. In
these situations, a treatment train should be
implemented that uses bioremediation, thermal
desorption, or incineration to address organic
contamination, followed by the immobilization of any
significant residual inorganic contamination. There
are limited full-scale performance data available on the
immobilization of PAHs and PCP, either alone or
commingled with inorganic contamination, where the
concentration of total petroleum hydrocarbons is
significantly more than 1%. Immobilization has been
effective in treating soils with commingled organic and
inorganic contamination with a total organic content of
as much as 20-45%. Immobilization alone is not
effective for treating volatile organic contaminants.
Site-specific treatability studies should be conducted to
ensure that a solidification/stabilization formulation
can be developed that meets site-specific requirements
for low teachability and permeability, and high
compressive strength. EPA is currently in the process
of developing guidance on conducting
solidification/stabilization treatability studies.
PRESUMPTIVE REMEDY PROCESS FOR
WOOD TREATER SITES
This section and the accompanying "Decision Tree for
Technology Selection at Wood Treater Sites" (Figure
1) describe the process for selecting a presumptive
remedy or combination of remedies for cleaning up
contaminated soils, sediments, and sludges at wood
treater sites. This remedy selection process is
consistent with and fits into the overall site
remediation process outlined in the NCP.
Under the NCP, alternative remedies are to be
evaluated and the preferred alternative is to be selected
based on nine criteria. Presumptive remedies are
technologies that have been found to be generally
superior under the nine criteria to other technologies.
This generic evaluation makes it unnecessary to
conduct a detailed site-specific analysis of the other
technologies.
The "decision tree" approach recommended here is a
further streamlining.of the usual NCP analysis. The
decision tree is based on the Agency's findings that,
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among the recommended technologies, a single
preferred technology can be identified based on the
nine criteria, but that the determination of which
technology is preferred will depend on a few key
variables such as the types of contaminants present and
the feasibility of the technology. Once these factors
are determined, the single recommended approach can
be identified. This conclusion represents a judgement
that, under the circumstances at the site, the preferred
technology will be superior under the nine criteria.
However, the decision tree avoids the need to go
through a full nine-criteria analysis at the site-specific
level; in effect, most of that analysis has already been
performed and the only information needed to
complete the analysis relates to variables specified in
the decision tree.
The presumptive remedy process generally begins at
the point in the overall NCP process where the
removal and/or remedial site evaluation and Hazard
Ranking System scoring steps have been completed and
development of the RI/FS or EE/CA is about to begin.
The presumptive remedy process streamlines the site
characterization, technology assessment, and remedy
selection steps.
The decision tree describes a presumptive remedy
process that is dynamic, where site characterization, the
evaluation of presumptive remedies, and the
establishment and refinement of remedial action
objectives (including future land use assumptions and
Preliminary Remediation Goals (PRGs)) are conducted
interactively and concurrently. Site managers should
attempt to involve the state, community, and
potentially responsible parties (PRPs) in the
presumptive remedy process as early as possible.
Presumptive remedy options should be evaluated
considering their associated performance efficiencies
and the cleanup levels they might achieve, and the
future land uses that their implementation may make
available. In most cases, treatability studies should be
performed for the treatment technologies being
considered. As discussed previously, the identification
of presumed or likely remedies early in the cleanup
process will allow for a more focused collection of data
on the extent of contamination, eliminate the need for
the initial step of identifying and screening alternatives
during the FS or EE/CA, and streamline the detailed
analysis phase of the FS or EE/CA.
The numbered steps and decision points in Figure 1,
the "Decision Tree for Technology Selection at Wood
Treater Sites," correspond to the similarly numbered
paragraphs below. These paragraphs provide
information and the underlying assumptions for each of
the different steps and decision points in the
presumptive remedy process. The decision tree should
be used as a guide through the specific decision points
and considerations that are necessary to choose a
presumptive remedy.
1. Are Creosote, PCP, or CCA Present at the Site?
This document focuses on cleaning up soils,
sediments, and sludges at wood treater sites
contaminated primarily with creosote, PCP, or
CCA; if these contaminants are not present at the
site, the presumptive remedy selection process
outlined in the document is not appropriate for
the site, and the conventional RlfFS or EE/CA
process should be followed. Information on
contaminants present at the site may be available
from data collected during the removal and/or
remedial site evaluation. If this information is
not available, past chemical use at a particular
facility can be ascertained from a number of
sources, such as information from facility records,
past sampling efforts by state or local agencies, or
through information request letters.
2. Initiate Early PRP, State, and Community
Involvement. Site managers should initiate a
dialogue with the community, state
representatives, and PRPs early in the process of
identifying potential presumptive remedy options
for a site. This dialogue should include a
discussion of reasonably anticipated future land
use. This discussion should be beneficial in
establishing remedial action objectives and state
ARARs, which, in conjunction with federal
requirements, may provide PRGs. In addition,
site managers should begin assembling the
Administrative Record for the site.
3. Review Advantages/Limitations Table for
Presumptive Remedies. Using information on the
contaminants present at the site, site managers
should begin reviewing the presumptive remedies
for wood treater sites. Table 1 provides a listing
of the presumptive remedies for wood treater sites
and the contaminants for which they are
applicable. Table 2 provides detailed information
on the advantages, limitations, and costs of each
of the presumptive remedies.
Steps 4 and 5 of the decision tree represent
separate aspects of initial site cleanup activities.
However, these steps should be undertaken
concurrently, with each step using information
obtained from the other step.
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TABLE 1
Evaluation of Presumptive Remedy Technology Options
Contaminants
Present at Site
Oraanics:
Creosote,
PCP, or
Creosote and PCP
Inorganics:
CCA
Oreanics and Inorganics:
Creosote and CCA;
PCP and CCA; or
Creosote, PCP, and CCA
Presumptive Remedy
Technology Options
Bioremediation
Thermal Desorption
Incineration
Immobilization
Bioremediation, Thermal
Desorption, and/or
Incineration, followed by
Immobilization
Demonstrated Performance
Efficiencies1
64-95% for PAHs and 78-98% for
chlorophenols (F)2
82-99% (B,P,F)
90-99% (B,P,F)
80-90% TCLP3 (B,P,F)
See above
1 Performance represents a range of treatability data. Percentages may vary depending on the contaminants). Bench-
(B), pilot- (P), or full-scale (F) demonstration data may not be available for all contaminants. All performance
efficiency data are taken from EPA's Contaminants and Remedial Options at Wood Preserving Sites [8], unless noted
otherwise.
2 These data represent current full-scale performance data for ex situ bioremediation conducted at three U.S. wood
treater sites (all of which are listed on the National Priorities List (NPL)) and one Canadian wood treater site. The use
of bioremediation at these four sites achieved remediation goals in all cases. Because the monitoring of biodegradation
at these sites stopped after remediation goals were achieved, actual performance efficiencies at these sites may be higher
•than these numbers indicate. For a more detailed discussion of these performance data, see "Full-Scale Performance
Data on the Use of Bioremediation at Wood Treater Sites," a technical background document for the wood treater site
presumptive remedy initiative that is available at EPA Headquarters and the Regional Offices. EPA's Contaminants
and Remedial Options at Wood Preserving Sites (1992) [8] provides the following pilot-scale performance data for
bioremediation: an average of 87% for PAHs and 74% for halogenated phenols and cresols. The effectiveness of
bioremediation tends to be highly variable and very site-specific. A significant component of this variability is the range
of effectiveness in the remediation of different kinds of PAHs; studies on the bioremediation of creosote contamination
indicate that bioremediation works well on 2-, 3-, and often 4-ring PAHs, but generally not as well on 5- or 6-ring
PAHs. For example, the use of ex situ bioremediation at one of the wood treater NPL sites resulted in 95% removal
of 2-ring PAHs, 83% removal of 3-ring PAHs, and 64% removal of 4+-ring PAHs. In practice, in situ bioremediation
typically results in lower performance efficiencies than the ex. situ process because in situ reactions are less controlled
and involve lower mass transfer rates. To obtain additional performance data for bioremediation, contact the U.S.
EPA's Center for Environmental Research Information (CERI) at: 26 W. Martin Luther King Drive, Cincinnati, Ohio
45268. CERI maintains a bioremediation data base called "Bioremediation in the Field Search System" (BFSS), which
may be accessed electronically through bulletin boards at (301) 589-8366 or (513) 569-7610.
3 TCLP (toxicity characteristic leaching procedure) is a specific analytical method; this method has been widely used
in the past to evaluate the performance of immobilization. However, current information indicates that the SPLP
(synthetic precipitation leaching procedure) or other procedures using distilled or site-specific water will produce more
accurate results.
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Conduct Site Characterization. Site
characterization activities for wood treater sites
using the presumptive remedy process should he
designed 10:
• Positively identity the site type (i.e., a wood
treater site with creosote, PCP, or CCA
contamination);
• Obtain data to determine whether the
presumptive remedies are feasible for the
site;
• Focus and streamline the collection of data
to support the selection of presumptive
remedies only; and
• Collect design data, thereby streamlining the
data collection required during the remedial
or removal design stage.
The overall site characterization process should
proceed using multimedia sampling events
whenever possible. Field screening methods
should be integrated into the sampling and
analysis plan to accelerate information gathering.
Data quality objectives must reflect the ultimate
use of the results; consequently, all samples taken
during a single event may not require the same
level of data quality.
Surface lagoons, soil areas, drip pads, and
sediments should be sampled in a grid-like
manner to determine the horizontal and vertical
extent of contamination. Site managers should
ensure that sampling for dioxins and furans is
conducted at all wood treater sites known to have
used chlorinated phenols, such as PCP. Soil,
sediment, and sludge characterization relevant to
treatment selection should reflect the information
needs described in Tables 3A-D.
If a wood treating or other chemical at an
abandoned site is still in its original containers, it
should be returned to the manufacturer, if
possible. Where any of the principal wood
treating chemicals (creosote, PCP, or CCA) can
be recovered in high enough concentrations to
warrant reuse in any process, recycling becomes
the preferred technology. The recognized U.S.
Waste Exchanges are listed in Appendix A of the
Technology Selection Guide for Wood Treater
Sites [43].
During site characterization, a site-specific
baseline risk assessment (or streamlined risk
evaluation for a removal action) should be
conducted to characterize materials that constitute
principal threats (i.e., source materials, including
liquids, that arc highly toxic or highly mobile
wastes that generally cannot be reliably contained
or would present a significant risk to human
health and the environment should exposure
occur). This risk assessment should be conducted
to determine whether sufficient threats or
potential threats exist to warrant a response
action.
The site-specific risk assessment should be used to
determine remediation goals for the site. Risk-
based remediation goals are often different for
soils, sediments, and sludges at different depths.
Shallow remediation goals are usually based on
direct contact risks, while deeper remediation
goals are usually based on ground-water impacts.
Site managers should consider the ground-water
strategy for the site because remediation goals for
soils, sediments, and sludges are often set to
protect ground-water quality. As discussed above,
existing guidance on the remediation of ground
water [6, 7, 17, 20, 38] and the forthcoming
guidance on a presumptive ground-water
approach, when available, should be consulted.
EPA is currently in the process of developing
guidance on soil screening levels [30]; these levels
represent contaminant concentrations in soil
below which there is generally no need for federal
concern for the protection of human health in a
residential setting. When the final guidance is
available, site managers should use it as a
screening tool in determining the need for further
assessment of soil contamination during the RI
stage of cleanups at National Priorities List sites.
For more information on conducting site
characterization activities and risk assessments,
site managers should refer to the references listed
at the end of this document [1, 8, 16, 19, 23, 34
35, 36].
Establish Remedial Action Objectives (Including
Land Use Assumptions) and Set PRGs.
Promulgated federal and state standards should be
assessed as potential ARARs for the site. As
appropriate, other criteria, advisories, or guidance
should be assessed as potential to be considered*
(TBCs). For a more detailed discussion on
identifying ARARs and TBCs, see the references
listed at the end of this document [3, 4, 41].
Superfund site managers should also continue to
evaluate the presumptive remedies and begin to
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develop remedial action objectives for the site.
The following steps, as depicted in Figure 1,
should be undertaken by site managers.
Review Presumptive Remedies and Associated
Performance Efficiencies
Site managers should continue the review of the
presumptive remedies that was initiated in Step 3,
using additional infonnation on site characteristics
obtained under Step 4. Tables 1 and 2 provide
data on performance efficiencies for the different
presumptive remedy technologies. Information
contained in these tables should be used to focus
the information gathering activities being
conducted under the site characterization step.
Set Preliminary Remediation Goals
As part of the overall remedial action objectives
for the site, site managers should set PRGs.
Initially, PRGs should be developed based on
readily available information, such as ARARs and
TBCs. Technical, exposure, and uncertainty
factors should also be used to establish PRGs (see
section 300.430(e)(2) of the NCP). Site managers
should modify PRGs, as necessary, as more
infonnation becomes available. When setting
PRGs for wood treater sites, site managers should
also consider the performance efficiencies of the
different presumptive remedies. In most cases,
treatability studies will be necessary to determine
the site-specific capabilities of a specific
presumptive remedy. Reasonably anticipated
future land use(s) of the site should also be
considered when establishing PRGs. Site
managers should consult EPA's guidance on land
use in the Superfund remedy selection process
[27]. This guidance calls for early interaction with
citizens, local governments, and other entities to
gather information to develop assumptions
regarding anticipated future land use. These
assumptions may be used in the baseline risk
assessment, the development of alternatives, and
remedy selection. Refer to, Box E (Practical
Considerations) for more information on future
land use considerations.
Prepare Information and Present to Public
It is important that site managers involve the
public at an early stage in the consideration of the
various presumptive remedy options. Site
managers should encourage the public to review
the advantages and limitations of the presumptive
remedies against each other and should consider
this public input when selecting a presumptive
• remedy for a site. In particular, efforts should be
made to engage the community and other
interested parties in discussions concerning the
establishment of PRGs and future land use issues.
Input from the community, state representatives,
and PRPs may be obtained through a variety of
methods, such as informal contacts or meetings
with community leaders or groups. This early
input on remedy selection should assist site
managers in fostering community acceptance at
later stages of the presumptive remedy selection
process. Before seeking public input, the site
manager should do the following: (1) contact
Regional community relations staff for
information on community acceptance (if further
assistance is necessary, the individuals listed in
Box B should be contacted); and (2) prepare a
matrix of the applicable presumptive remedy
options for the site. This matrix should contain
data on the performance efficiencies, advantages,
limitations, costs, and implementability of the
various options, and should emphasize the full
range of trade-offs between the alternatives. This
information should be presented to the public to
assist them in providing input on the remedy
selection process. For a more detailed discussion
on holding public meetings and community
relations at Superfund sites, see the references
listed at the end of this document [5, 42].
Evaluate Public Reaction to the Presumptive
Remedy Options
If the public reacts favorably to one or more of
the presumptive remedy options, site managers
should proceed to the next step of the
presumptive remedy process. However, if the
public does not react favorably to any of the
presumptive remedy options under consideration,
site managers may wish to consider reviewing
non-presumptive technologies, including
innovative technologies, to determine if there are
other options that may receive greater community
acceptance while providing for sufficient overall
protection of human health and the environment.
If this is the case, a conventional RI/FS or EE/CA
could be performed, or the FS could consider the
presumptive remedy plus any specific alternatives
believed to warrant consideration to establish a
site-specific Administrative Record that supports
the selection of a technology that is not
specifically identified as a presumptive remedy.
Site managers should note that all alternatives
should generally be evaluated in a full nine-
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criteria analysis, even if objections are raised by
members of the community. However, if
opposition is intense, it may be justifiable to
screen out an alternative early in the process for
reasons of implementability.
6. Conduct Time-Critical Removal Action, if
Necessary. Information from site characterization
activities may indicate that the performance of a
time-critical removal action is warranted. If so,
site managers should conduct the removal action
in accordance with the NCP and EPA removal
program guidance. If subsequent non-time-critical
removal actions or remedial actions are still
required at the site, site managers should follow
the presumptive remedy process, if appropriate.
7. Identification of New Contaminants. Continuing
site characterization efforts performed under Step
4 may, at any time, identify new contaminants at
the site. Newly identified contaminants should be
evaluated to determine if their presence precludes
using presumptive remedy technologies or makes
the use of these technologies inappropriate. For
example, the detection of significant DNAPL
contamination of ground water at a site may
indicate that contaminated soils, sediments, or
sludges do not pose a principal human health and
environmental threat and, therefore, may not
require treatment or may only need to be
contained. In these situations, site managers
should follow the presumptive remedy approach
for contaminated ground-water sites, when
available. If newly identified contaminants do
preclude or make inappropriate the use of a
presumptive remedy identified in this document,
this directive may not be applicable and the
conventional RI/FS or EE/CA process may need
to be followed.
8. ReOne PRGs. Is There a Need for Further
Action? Using additional information obtained
from the site-specific baseline risk assessment, site
managers should determine whether the site poses
an unacceptable risk to human health or the
environment. If the site does not pose an
unacceptable risk, no further action is required.
However, if it appears that an unacceptable risk
does exist, site managers should proceed to the
next step in the presumptive remedy process.
Information from the baseline risk assessment
should be used to refine the PRGs for the site.
9. Proceed with Technology Assessment and Review
"Practical Considerations." After it has been
determined that a cleanup action is warranted at
the site, site managers should review the different
presumptive remedy options and identify a
proposed option. For a remedial action,
presumptive remedy options must be evaluated
against the nine criteria required by section
300.430(e)(9) of the NCP; this should be
documented in the detailed analysis section of an
FS or Focused FS. Appendix A of this document
summarizes the analysis EPA conducted on
FSs/RODs for wood treater sites with
contaminated soils, sediments, or sludges, and
Appendix B provides generic evaluations of the
different presumptive remedies against seven of
the nine remedial criteria (excluding state and
community acceptance). Both of these appendices
should be used to streamline the detailed analysis
phase of the FS. Appendices A and B can also be
used to streamline the evaluation of removal
action alternatives in an EE/CA The generic
analyses in Appendix B should be supplemented
with site-specific information for the final
response selection. During technology
assessment, the factors listed in the "Practical
Considerations" section (Box E) of this document
should be reviewed to ensure a comprehensive
evaluation of response alternatives.
10. Begin the Technology Selection Process Based on
the Types of Contamination Present at the Site.
If the only contaminants present at significant
levels (i.e., levels that may justify treatment) are
inorganics, site managers should follow Path A in
Figure 1 (i.e., proceed to Step 11) and evaluate
the feasibility of immobilization. If the only
contaminants present at significant levels are
organics, site managers should follow Path B in
Figure 1 (i.e., proceed to Step 12) and evaluate
the feasibility of bioremediation. In situations
where significant levels of both inorganic and
organic contamination are present at the site, site
managers should follow Paths A and B
concurrently. In these situations, a treatment
train should be implemented that uses
bioremediation, thermal desorption, and/or
incineration to address the organic contaminants
and immobilization to address the inorganic
contaminants.
11. Is Immobilization Feasible? Immobilization is the
primary presumptive remedy for addressing
significant levels of inorganic contamination in
soils, sediments, and sludges at wood treater sites.
If immobilization is not considered feasible for
addressing inorganic contaminants present at the
site, this document is not applicable and site
managers should review other non-presumptive
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technologies. If the use of immobilization is
feasible, site managers should proceed to Step 15.
12. Is Bioremediation Feasible? Bioremediation is
the primary presumptive remedy for treating
organic contamination of soils, sediments, and
sludges at wood treater sites. However, the
effectiveness of bioremediation is very site- and
contaminant-specific. In addition, implementation
of bioremediation remedies requires considerably
more time than the implementation of the other
presumptive remedies (i.e., several years for
bioremediation as compared to approximately six
months to a year for thermal desorption and
incineration). Bioremediation can successfully
treat soils, sediments, and sludges contaminated
with organic contaminants such as haiogenated
phenols and cresols, other polar organic
compounds, non-halogenated aromatics, and
PAHs (particularly 2- and 3-, and often 4-ring
compounds). However, bioremediation may not
be feasible if a site exhibits high levels of
concentrated residual creosote or dioxins and
furans. Pilot/treatability study testing should be
conducted to assess the feasibility of using
, bioremediation at a site. If the use of
bioremediation is feasible, site managers should
. proceed to Step 15. If the use of bioremediation
is not feasible, site managers should assess the use
of thermal desorption.
13. Is Thermal Desorption Feasible? If
bioremediation will not be sufficiently effective in
achieving PRGs for the site, thermal desorption
should be considered as the presumptive remedy
for addressing organic contamination. Treatability
studies should be conducted (including a Proof of
Performance test if dioxin and/or furan formation
is a concern) to ensure that thermal desorption is
feasible for the site and will achieve the desired
PRGs. If the use of thermal desorption is
feasible, site managers should proceed to Step 15.
If the use of thermal desorption is not feasible,
site managers should assess the use of
incineration.
14. Is Incineration Feasible? If high contaminant
concentrations and/or treatability testing indicate
that thermal desorption will not achieve the
desired PRGs for the site, incineration should be
considered as the presumptive remedy. If the use
of incineration is feasible for the site, site
managers should proceed to Step 15. If none of
the three presumptive remedy options for treating
organic contaminants are considered feasible for
the site, this document is not applicable and site
managers should review other non-presumptive
technologies.
15. Proceed with ROD or Action Memorandum. At
this point in the process, site managers should
possess sufficient information to set final
remediation goals and identify a preferred
presumptive remedy option. This preferred
option should be presented to the public for
review and comment in the proposed plan.
Because substantial community input has already
been factored into the remedy selection process
under Step 5, it is envisioned that significant
negative input from the public should not be
received at this point.
The final step in the selection of a presumptive
remedy is to document the decision in a ROD for
a remedial action or an Action Memorandum for
a removal action. As was discussed above, if a
presumptive remedy is selected in the ROD or
Action Memorandum, a copy of this document
and its accompanying attachments must be
included in the Administrative Record for the
site. These materials will assist in justifying the
selection of the presumptive remedy, and will
support the elimination of the initial screening
step of the FS or EE/CA and the streamlining of
the detailed analysis phase of the FS or EE/CA
CONCLUSION
The presumptive remedies for cleaning up soils,
sediments, and sludges at wood treater sites that are
contaminated primarily with creosote, PCP, or CCA
are bioremediation, thermal desorption, incineration,
and immobilization. Bioremediation is the primary
presumptive remedy for treating organic contaminants,
followed by thermal desorption and incineration!
respectively. Immobilization is the primary
presumptive remedy for treating inorganic
contaminants. Based on site-specific information and
remediation goals established for the site, one or more
of these treatment technologies should be selected. If
a wood treater site does not meet the conditions
described in this document, the document is not
applicable and the conventional remedy selection
process should be followed.
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BOX D
Background Information on NAPL Contamination
A non-aqueous phase liquid (NAPL) is a liquid that, in its pure form, does not readily mix with water but slowly
partitions into the water phase. Dense NAPLs (DNAPLs) sink in water, while light NAPLs (LNAPLs) float on water.
When present in the subsurface, NAPLs slowly release vapor and dissolved phase contaminants, resulting in a zone of
contaminant vapors above the water table and a plume of dissolved contaminants below the water table. The term
NAPL refers to the undissolved liquid phase of a chemical or mixture of compounds, and not to the vapor or dissolved
phases. NAPLs may be present in the subsurface as either "free-phase" or "residual-phase" NAPLs. The free-phase is
that portion of the NAPL that can continue to migrate and can flow into a well. The residual-phase is that portion
trapped in pore spaces by capillary forces, which cannot generally flow into a well or migrate as a separate liquid. Both
residual- and free-phase NAPLs are sources of vapors and dissolved contaminants.
The most common LNAPLs are petroleum fuels, crude oils, and related chemicals, which tend to be associated with
facilities that refine, store, or transport these liquids. The following factors tend to make LNAPLs generally easier to
locate and clean up than DNAPLs: (1) LNAPL contamination tends to be more shallow than DNAPL contamination;
(2) LNAPLs tend to be found at the water table; and (3) LNAPLs are usually associated with specific types of facilities.
However, LNAPL contamination that is trapped in soil pores below the water table may not be significantly easier to
remediate than DNAPL contamination in the saturated zone.
DNAPLs pose difficult cleanup problems. These contaminants include chemical compounds and mixtures with a wide
range of chemical properties, including chlorinated solvents, creosote, coal tars, PCBs, PCP, and some pesticides. Some
DNAPLs, such as coal tars, are viscous chemical mixtures that move very slowly in the subsurface. Other DNAPLs,
such as some chlorinated solvents, can travel very rapidly in the subsurface because they are heavier and less viscous
than water. A large DNAPL spill not only sinks vertically downward under gravity, but can spread laterally with
increasing depth as it encounters finer grained layers. These chemicals can also contaminate more than one aquifer
by penetrating fractures in the geologic layer that separates a shallow aquifer from a deeper aquifer. Thus, large releases
of DNAPLs can penetrate to great depths and can be very difficult to locate and clean up.
The contamination problem at DNAPL sites has two different components: (1) the aqueous contaminant plume, and
(2) the DNAPL zone, as shown in Figures D-l and D-2. The aqueous contaminant plume includes those portions of
the site where only dissolved contaminants are present in ground water. The DNAPL zone includes those portions of
the site where immiscible liquids are present in the subsurface, either as free-phase or residual-phase compounds.
Depending on the volume of the release and the subsurface geology, the DNAPL zone may extend to great depths and
over large lateral distances from the entry location.
For a more detailed discussion on DNAPL contamination, see the references listed at the end of this, document [7 10
11, 12, 13, 15, 17].
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BOX D
Background Information on NAPL Contamination
(continued)
FIGURE D-1
Components of DNAPL Sites
DNAPL Zone
contains free-phase DNAPL in pools
orlanses and/or residual DNAPL
DNAPL Entry Location
such as a former waste pond
Ground-Water Row
<
FIGURE D-2
Types of DNAPL Contamination and Contaminant Zones at DNAPL Sites
(Cross-Sectional View)
Page 17
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BOXE
Practical Considerations
Land use: In general, remedial action objectives should be formulated to identify response
alternatives that will achieve cleanup levels appropriate for the reasonably anticipated future land use
of a site. Early community involvement, with a particular focus on the community's desired future
uses of property associated with the site, should result in a more democratic decisionmaking process,
greater community support for remedies selected as a result of this process, and, in many cases, more
expedited cleanups. Factors to consider may include: any recommendations or views expressed by
members of the affected community; the land use history and current uses of the facility and
surrounding properties, and recent development patterns where the facility is located; and the
proximity of the contamination to residences, sensitive populations or ecosystems, natural resources,
or areas of unique historic or cultural significance. For example, if it is anticipated that a site will
be used for future industrial/commercial development, it may be appropriate to select a presumptive
remedy (e.g., in situ bioremediation) that results in higher residual contaminant levels but is less costly
than other options. EPA has developed guidance on land use in the Superfund remedy selection
process [27].
Institutional and/or engineering controls: It may be appropriate to use institutional and/or
engineering controls in conjunction with the presumptive remedy technologies described in this
document to reduce current or potential human exposure via direct contact with contaminated soils,
sediments, and sludges or through the use of contaminated ground water..* Engineering controls are
physical systems requiring construction and maintenance, such as soil caps, caps with liners, and
vertical barrier walls. Institutional controls include the use of physical barriers, such as fences and
warning signs, and the use of administrative restrictions, such as deed or lease restrictions. When
vigorously enforced, institutional controls limit direct contact with and ingestion of soils, sediments,
and sludges; however, unlike some engineering controls (e.g., caps), institutional controls do not
reduce the potential for wind dispersal and inhalation of contaminants. Monitoring is generally
needed to determine the effectiveness of institutional and/or engineering controls.
Institutional and/or engineering controls alone do not satisfy CERCLA's preference for achieving
reductions of toxicity, mobility, or volume through treatment as a principal element of the remedy.
Consequently, they are not generally recommended as the sole response to address contaminants that
are deemed a principal threat at wood treater sites. However, the use of institutional and/or
engineering controls after the treatment of a principal threat by one or more of the presumptive
remedy technologies can enhance the long-term reliability of the remedy.
A cap is an engineering control that may be particularly useful in improving the overall protection
of a presumptive remedy. A simple cap may involve only covering the treated area with
uncontaminated native soil and/or seeding, fertilizing, and watering the area until vegetation has been
established. A simple cap (soil only) may be appropriate for situations where direct contact and/or
erosion are the prime threats, and is particularly appropriate following bioremediation because it
ensures oxygen availability for continuing biodegradation. Caps that are intended to prevent surface
water infiltration are typically comprised of soil and several other components, including a drainage
layer, a geomembrane, and a compacted clay layer. Such caps, in addition to being effective in
limiting direct contact exposure and reducing erosion, are also effective in limiting surface water
infiltration, minimizing the vertical migration of residual contaminants, and minimizing ground-water
contamination. However, caps that prevent infiltration will inhibit aerobic biodegradation, which
generally makes the use of such caps following bioremediation inappropriate. For a more detailed
discussion on the factors affecting the appropriate uses of caps, refer to the references listed at the
end of this document [14, 18, 29].
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BOX E
Practical Considerations
(continued)
Treatment trains: A single technology may not be sufficient to clean up an entire wood treater site.
Remediation of sites often requires a combination of control and treatment options in order to
sufficiently reduce toxicity and immobilize contaminants. The treatment train concept combines
pretreatment and/or post-treatment activities with treatment technologies to achieve site-specific
objectives and acceptable residual contaminant levels. For example, the implementation of a remedy
might include institutional controls to control direct contact exposure, bioremediation to treat organic
contamination (including excavation, capping, and monitoring activities), and immobilization to treat
residual inorganic contamination. The pretreatment and post-treatment portions of the treatment
train should be selected based on site-specific considerations.
"Hot spots": Hot spots (e.g., highly contaminated sludges) are generally defined as discrete areas
within a site that contain hazardous substances, pollutants, or contaminants that are present in high
concentrations, are highly mobile, or cannot be reliably contained, and would present a significant risk
to human health or the environment should exposure occur. Hot spots will usually be considered
principal threats at a site, as defined by the NCP. Site managers should be aware that the limitations
of certain presumptive remedies (e.g., bioremediation) may preclude their use in cleaning up certain
hot spots. In addition, responding to hot spots may require additional pretreatment and post-
treatment activities, such as the use of institutional controls or capping. (For additional information,
see the references listed at the end of this document [23].)
Land disposal restrictions (LDRs): All technologies that treat hazardous waste ex situ may cause the
waste being treated to be subject to RCRA LDRs. In situ treatment of hazardous waste does not
trigger LDRs because "placement" of the waste does not occur. LDRs establish treatment standards
that must be met before a waste can be land disposed. These treatment standards are either
concentration-based (hazardous constituents must be reduced to a set concentration) or, less
frequently, technology-based (waste must be treated using a specified technology). EPA has
promulgated LDR treatment standards for specific wood preserving wastes (K001 - sediments and
sludges from the treatment of wastewaters resulting from processes using creosote or PCP) and
anticipates proposing treatment standards for other wood preserving wastewaters in 1995. The
Agency has also promulgated LDR treatment standards for RCRA characteristic wastes. If a wood
treater waste exhibits one or more of the identified hazardous characteristics, it is subject to RCRA
LDRs.
Wood treater wastes that qualify as "remediation wastes" and are placed in a Corrective Action
Management Unit (CAMU, see 58 FR 8658-8685), whether at a Superfund site or RCRA corrective
action site, do not have to meet LDRs. (Whether LDRs are triggered depends on whether
remediation wastes are "placed" in a land-based unit, not on whether they are treated. LDRs do not
apply to remediation wastes treated on-site and then placed in a CAMU.) The EPA Region is
responsible for setting site-specific requirements for a CAMU, which could include LDRs. The LDR
program also provides four exceptions to meeting LDRs that may be applicable to wood treater sites:
(1) the treatability variance (see 40 CFR 268.44); (2) equivalent treatment; (3) the no-migration
exemption (see 40 CFR 268.6); and (4) de-listing. The treatability variance is anticipated to be the
primary route of compliance with LDRs for contaminated soil and debris; for more information, see
the references at the end of this document [39, 40]. Site managers should consult with Regional
RCRA program staff when addressing LDR issues at specific wood treater sites.
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TABLE 2
Comparison of Presumptive Remedy Technologies
Note: Performance represents a range of treatability data. A number of variables, such as concentration and distribution of contaminants, matrix particle size,
and moisture content can affect system performance. Bench- (B), pilot- (P), or full-scale (F) performance data may not be available for all contaminants. The
performance efficiency data are taken from U.S. EPA's Contaminants and Remedial Options at Wood Preserving Sites [8], unless noted otherwise.
TECHNOLOGY
PERFORMANCE
ADVANTAGES
LIMITATIONS
COST
Bioremediation
(ex situ)
64 - 95% for PAHs,
78 - 98% for
chlorophenols (F)1
More suitable for higher concentrations of
organic contaminants than in situ processes.
Solid-phase treatment has been successfully
demonstrated at wood treater sites.
Generally receives wide community
acceptance.
May require treatabilily studies due to a
scarcity of full-scale performance data.
Bench- or pilot-studies may be necessary.
Efficiency limited by lack of indigenous
microbes, toxic metals, highly chlorinated
organics, pH outside of 4.5 - 8.5 range,
limited growth factors, or rainfall/
evapotranspiration rate/percolation rate
ratio too high or too low.
Increases the volume of treated materials if
bulking agents are added.
Excavation and material handling add to
costs.
Land treatment of wastes is subject to land
disposal restrictions (LDRs), unless "no-
migration" is demonstrated.
$50 - S150 per cubic
yard of soil, sediment,
or sludge; or
approximately $40 -
$125 per ton of soil,
sediment, or sludge.
These data represent current full-scale performance data for bioremediation conducted at three U.S. wood treater sites (all three of which are
listed on the NPL) and one Canadian wood treater site. The use of bioremediation at these four sites achieved remediation goals in all cases. Because
the monitoring of biodegradation at these sites stopped after remediation goals were achieved, actual performance efficiencies at these sites may be higher
than these numbers indicate. For a more detailed discussion of these performance data, see "Full-Scale Performance Data on the Use of Bioremediation
at Wood Treater Sites," a technical background document supporting the wood treater site presumptive remedy initiative that is available at EPA
Headquarters and Regional Offices. EPA's Contaminants and Remedial Options at Wood Preserving Sites (1992) [8] provides the following pilot-scale
performance data for bioremediation: an average of 87% for PAHs and 74% for halogenated phenols and cresols. The effectiveness of bioremediation
tends to be highly variable and very site-specific. A significant component of this variability is the range of effectiveness in the remediation of different
kinds of PAHs; studies on the bioremediation of creosote contamination indicate that bioremediation works well on 2-, 3-, and often 4-ring PAHs, but
generally not as well on 5- or 6-ring PAHs. For example, the use of ex situ bioremediation at one of the wood treater NPL sites resulted in 95% removal
of 2-ring PAHs, 83% removal of 3-ring PAHs, and 64% removal of 4+-ring PAHs. To obtain additional performance data for bioremediation, contact
the U.S. EPA's Center for Environmental Research Information (CERI) at: 26 W. Martin Luther King Drive, Cincinnati, Ohio 45268. CERI maintains
a bioremediation data base called "Bioremediation in the Field Search System" (BFSS), which may be accessed electronically through bulletin boards
at (301) 589-8366 or (513) 569-7610.
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0
umptive
Comparison of Presumptive Remedy Technologies
(continued)
TECHNOLOGY
Bioremediation
(in situ)
PERFORMANCE
=====
51% for PAHs,
72% for PCP (F)2
ADVANTAGES
Suitable for moderate concentrations of
organic contaminants.
Can destroy organic contaminants in place
without the high costs of excavation and
material handling.
Minimizes the release of volatile
contaminants into the air.. .
Generally receives wide community
acceptance.
LIMITATIONS
=====
1 .May require treatability studies due to a
scarcity of full-scale performance data.
Bench- or pilot-scale studies may be
necessary.
Efficiency limited by lack of indigenous
microbes, toxic metals, highly chlorinated
organics (e.g., even high levels of PCP), pH
outside of 4.5 - 8.5 range, limited growth
factors, non-uniform contaminant
distribution, or rainfall/evapotranspiration
rate/percolation rate ratio too high or too
low. For example, low-permeability soils
can hinder performance; however, hydraulic
fracturing or other methods may be used to
overcome this problem, at higher operating
costs.
Cannot be used to directly destroy
concentrated masses of non-aqueous phase
liquids (NAPLs).
COST
-
$50 - $100 per cubic
yard of soil, sediment,
or sludge.
2 These data represent current full-scale performance data from a bioremediation demonstration project conducted at a Canadian wood treater site
ind,v IT8 °f bi0 actual P^ormanc" efficiencies anh site may be Wgher than h«e
i^^ °f thCSe Perf°rmanCe dat3' SCe ™-Scale Prance Data on the Use of Bio'emedltiL at wS
anS of ,? ni^l bac^round document s«PPortmg the wood treater site presumptive remedy initiative that is available at EPA Headquarters
and Regional Offices EPA's Contaminants and Remedial Options at Wood Preserving s,v.s (1992) [8] provides the following pilot-scale
i h,
d nn
well on 5 or 6
rf don
"
SlgniflCant comPonent of this variabi% is the range of effectiveness in the remediation of different kinds of
^ ^^^ indicate that bioremediation works well on 2-, 3-, and often 4-ring PAHs, but generally
PH f ' "I ^ bl°remediation lyPically results in lowe^ performance efficiencies than the a situ process because
Ep ner R lnv^e lower mass transfer rates. To obtain additional performance data for bioremediation, contact the U.S.
EPAs Center for Environmental Research Information CERI) at: 26 W. Martin Luther King Drive, Cincinnati Ohio 45268 CERI maintains a
" ^ Fidd SCarCh SStem" BFSS WC e 3CC SSed elec« y ou^hS tin b^ ^ s a
Page 21
-------
TABLE 2
Comparison of Presumptive Remedy Technologies
(continued)
TECHNOLOGY
PERFORMANCE
ADVANTAGES
LIMITATIONS
COST
Thermal
Desorption
82 - 99% (B,P,F)
Thermal treatments are well-established
technologies for treating organic-
contaminated media.
Thermal desorption can often produce a
treated waste that meets treatment levels
set by the Best Demonstrated Available
Technology (BDAT) requirements of the
RCRA land disposal ban.
May warrant treatability studies due to a
scarcity of full-scale performance data.
Bench- or pilot-studies may be necessary.
Design and operation of unit and associated
air pollution control devices must take into
account the possible presence of
halogenated organics, mercury, or corrosive
contaminants.
Inorganic constituents that are not
particularly volatile will not be effectively
removed by thermal desorption.
If chlorine or chlorinated compounds are
present, some volatilization of inorganic
constituents in the waste may occur.
The contaminated medium must contain at
least 20 - 30% solids in order to facilitate
placement of waste material into treatment
equipment.
Wastes with high-moisture content may
need to be dewatered prior to processing in
order to control costs and achieve desired
performance.
Material handling of soils, sediments, or
sludges that are tightly aggregated or largely
clay can result in poor processing
performance due to caking.
S150-S400pcrtonof
soil, sediment, or
sludge, excluding
excavation, material
handling, or disposal
costs.
-------
Comparison of Presumptive Remedy Technologies
(continued)
TECHNOLOGY
PERFORMANCE
ADVANTAGES
LIMITATIONS
COST
Thermal
Desorption
(continued)
If a high fraction of fine silt or clay exists in
the matrix, fugitive dusts will be generated
and a greater dust loading will be placed on
the downstream air pollution control
equipment.
The total organic loading is limited by some
thermal, treatment systems to 10% or less
to ensure that Lower Explosive Limits
(LELs) are not exceeded.
A medium exhibiting a very high pH
(greater than 11) or low pH (less than 5)
may corrode thermal system components.
The treatment process may alter the
physical properties of the treated material,
particularly where waste matrices have a
high clay content. The treated product
should be evaluated to determine if the
product should be mixed with other
stabilizing materials or compacted.
Excavation and material handling add to
costs.
With chlorinated feed, potential for dioxin
and/or furan formation exists. Systems
must be designed and operated carefully.
A full-scale Proof of Performance test, with
dioxin and furan analysis if chlorinated feed
is present, should precede cleanup
operations.
Page 23
-------
IMDi-C
Comparison of Presumptive Remedy Technologies
(continued)
TECHNOLOGY
PERFORMANCE
ADVANTAGES
LIMITATIONS
COST
Incineration
90 - 99% (H.I'.F)
Ensures that specified cleanup levels can be
achieved for a given site.
Can effectively remove nearly all
contamination.
High moisture content reduces capacity of
incinerator.
Incineration of large volumes of
contaminants may be prohibitively
expensive.
Efficiency may be limited by high alkali
metals or elevated levels of mercury or
organic phosphorous.
If a high fraction of fine silt or clay exists in
the matrix, fugitive dusts will be generated
and a greater dust loading will be placed on
the downstream air pollution control
equipment.
A medium exhibiting a very high pH
(greater than 11) or low pH (less than 5)
may corrode incineration system
components.
Excavation and material handling add to
costs.
On-site incineration has the potential for
community concern/opposition.
S150 - $400 per ton of
soil, sediment, or
sludge, excluding
excavation, material
handling, or disposal
costs.
-------
TABCE2
Comparison of Presumptive Remedy Technologies
(continued)
TECHNOLOGY
PERFORMANCE
ADVANTAGES
LIMITATIONS
COST
Immobilization
80 - 90% TCLP3
(B.P.F)
• Treatability test data indicate that metals in
wood preservatives are amenable to
solidification/stabilization.
• Prevents/mitigates ground-water
contamination.
• Controls population exposure.
• Effectively contains contaminants.
• Reduces air emissions.
High levels of organic compounds can
retard or prevent setting of typical
solidification/stabilization matrices.
The particular solidification/stabilization
system that will perform well on a given
contaminated material must be determined
by site-specific screening and treatability
tests.
Efficiency may be limited by total
petroleum hydrocarbon (TPH) content
greater than 1%, or humic matter greater
than 20%.
$75 - $400 per ton
(with landfilling on-site)
and $100 - $500 per
ton (with landfilling 200
miles off-site).
Capping
N/A (not a treatment
technology)
Capping reduces surface-water infiltration,
reduces gas and odor emissions, improves
aesthetics, and provides a stable surface
over the waste.
Reduces direct contact exposure.
• Capping costs escalate as a function of
topographic relief.
• Does not treat contamination;
contamination is left in place.
• May slow down natural bioremediation
processes.
$1 - $16 per cubic yard
of capping material.
3 TCLP (toxicity characteristic leaching procedure) is a specific analytical method; this method has been widely used in the past to evaluate the
performance of immobilization. However, current information indicates that the SPLP (synthetic precipitation leaching procedure) or other procedures
using distilled or site-specific water will produce more accurate results.
Page 25
-------
TABLE 3-A
Data Requirements for Bioremediation
DATA REQUIREMENT
General Data Requirements
Biochemical oxygen
demand (BOD)
Chemical oxygen demand
(COD)
Contaminant solubility
Degradation rates of
contaminants
Indigenous microorganisms
Inorganic contaminants
Limiting initial and final
concentrations of
contaminants
Metals, inorganic salts
concentrations
Moisture content
Nutrients
Oil and grease content
Organic content
Particle size
Total organic carbon
(TOC)
IMPORTANCE OF INFORMATION
Provides estimate of biological treatability of soil, sediment, or sludge.
Another estimate of biological treatability. The measure of the oxygen
equivalent of organic content that can be oxidized by a strong chemical
oxidant.
Components with low solubility are difficult to remove from soil, sediment,
or sludge because of low bioavailability.
Should be determined through treatability studies. Important to determine
applicability of remedy.
The PAH biodegradation activity of indigenous organisms must be
measured to determine if appropriate microorganisms are present in
sufficient quantity.
Important to determine applicability of remedy.
Should be determined through treatability studies with respect to the
specific process.
High metal concentrations may inhibit microbial activity. Some inorganic
salts are necessary for biological activity.
May inhibit solid-phase aerobic remediation of soils, sediments, or sludges if
greater than 80% of field capacity; soil, sediment, and sludge remediation
inhibited if less than 40% of field capacity. Soil slurry reactors may operate
with 80-90% moisture content (water/weight of soil).
Lack of certain nutrients reduces activity.
Oil and grease concentrations may inhibit soil, sediment, and sludge
remediation at concentrations greater than 5% by weight, which may result
in unacceptable lag times.
Important to determine applicability of remedy. Important to determine
horizontal and vertical extent of contaminants and to ensure that
appropriate detection limits are used.
Particle size affects access and contact between microorganisms,
contaminants, nutrients, water, and electron acceptors.
Indicates total organic carbon present and can be used to estimate waste
available for biodegradation.
Page 26
-------
TABLE 3-A
Data Requirements for Bioremediation
(continued)
DATA REQUIREMENT
IMPORTANCE OF INFORMATION
General Data Requirements (continued)
Variable waste
composition
Redox potential (Eh)
Large variations affect biological activity.
Aerobic degradation: oxidation-reduction potential of the soil, sediment, or
sludge must be greater than that of the organic contaminant for oxidation to
occur.
Specific In Situ Data Requirements
Soil, sediment, or sludge
temperature
Position of water table
Site geology
Soil, sediment, or sludge
permeability
High or low temperatures affect microbial activity for in situ treatment (high
temperatures tend to increase activity, low temperatures tend to decrease
activity).
Important for remedy selection and implementation.
Important to determine mass transfer capability.
Affects movement of water, oxygen, and nutrients for in situ treatment.
Specific Ex Situ Data Requirements
Toxicity Characteristic
Leaching Procedure
(TCLP) analysis
Needed to determine if the soil, sediment, or sludge is a RCRA hazardous
waste.
Page 27
-------
TABLE 3-B
Data Requirements for Thermal Desorption
DATA REQUIREMENT
Bulk density of soil,
sediment, or sludge
Contaminant physical
properties
Inorganic contaminants
Metals content
Extent of organic
contaminants
Moisture content
Sulfur, chlorine, and
organic phosphorous
content
Particle size
PH
Salt content
Soil, sediment, or sludge
plasticity
Toacity Characteristic
Leaching Procedure
(TCLP) analysis
Flash point of soil,
sediment, or sludge
Total organic carbon
(TOC)
Total chloride
11
IMPORTANCE OF INFORMATION
Used in converting weight to volume in material handling calculations.
Information on physical properties, such as boiling point, determines the
required characteristics of the thermal desorption unit.
Important to determine applicability of remedy.
Metals (As, Cd, Cr, Pb, Zn) can vaporize at high temperatures and must be
removed from emissions.
Need to determine horizontal and vertical extent of organic contamination
to be excavated.
High moisture content increases feed handling and energy requirements.
Contribute to acid gas formations at high concentrations.
Oversized debris hinders processing. Fine particles can result in high
paniculate loading in flue gasses. Clay content will impede material
handling and may interfere with waste processing.
Extreme pH may be harmful to equipment.
High salt content, depending on temperature, may cause material in the
thermal unit to slag.
Plastic soil, sediment, or sludge, when subjected to compressive forces, can
become molded into large particles that are difficult to heat.
Needed to determine if the soil, sediment, or sludge is a RCRA hazardous
or listed waste.
Important to determine safe temperature parameters for the desorber unit.
Provides estimate of material available for combustion, which may affect the
temperature range available for thermal desorption.
Influences metal partitioning to the gas phase.
Page 28
-------
TABLE 3-C
Data Requirements for Incineration
DATA REQUIREMENT
Bulk density of soil,
sediment, or sludge
Contaminant combustion
characteristics
Heating value
Inorganic contaminants
Metals content
Extent of organic
contaminants
Moisture content
Sulfur, chlorine, and
organic phosphorous
content
Particle size
PH
Salt content
Soil, sediment, or sludge
plasticity
Toxicity Characteristic
Leaching Procedure
(TCLP) analysis
Total organic carbon
(TOC)
IMPORTANCE OF INFORMATION
Used in converting weight to volume in material handling calculations.
Required to determine the incinerator's combustion characteristics.
Affects throughput and energy requirements.
Important to determine applicability of remedy.
Metals (As, Cd, Cr, Pb, Zn) can vaporize at high temperatures and are
difficult to remove from emissions.
Need to determine horizontal and vertical extent of organic contamination
to be excavated due to cost concerns.
High moisture content increases feed handling and energy requirements.
Contribute to acid gas formations at high concentrations.
Oversized debris hinders processing. Fine particles can result in high
paniculate loading in flue gasses.
Extreme pH may be harmful to equipment.
High salt content will cause material in the incinerator to slag.
Plastic soil, sediment, or sludge, when subject to compressive forces, can
become molded into large particles that are difficult to heat.
Needed to determine if soil, sediment, or sludge is a RCRA hazardous or
listed waste.
Provides estimate of material available for combustion.
Page 29
-------
TABLE 3-D
Data Requirements for Immobilization
DATA REQUIREMENT
Coal or lignite content
Cyanides content
Halide content
Inorganic salts content
Metals content
Phosphate concentration
Oil and grease content1
Organic content1
Panicle size
Phenol concentration
Sodium arsenate, borate,
phosphate, iodate, sulfide,
sulfate, carbohydrate
concentrations
Solids content
Semi-volatile organics
Volatile organic
concentrations
IMPORTANCE OF INFORMATION
May affect product quality.
Affects bonding (greater than 3,000 ppm).
Retards setting; leaches easily.
Reduces product strength and affects curing rates (soluble salts of Mn, Sn,
Zn, Cu, and Pb).
Important for process considerations.
Phosphate is a key reagent in some solidification/stabilization mixes to
reduce metals (especially Pb) solubility, in high concentrations, phosphate
may cause problems.
Affects cementation, mix design, and cost.
Affects cementation, mix design, and cost.
Affects bonding (if less than 200 mesh or greater than 1/4 inch diameter).
Concrete is able to use larger particles.
Affects product strength (greater than 5%).
Retards setting and affects product strength.
Low solids content indicates that de-watering is needed.
Requires the use of special mixes, and may inhibit bonding
(if greater than 10,000 ppm).
Volatiles have not been successfully treated with solidification/stabilization
alone; volatiles should be removed or otherwise treated.
1 Immobilization with lime or proprietary additives has been used to treat oily soils and petroleum sludge at petroleum
industry sites; however, the structural properties of the product are poor, even when the material passes the TCLP
(Toxicity Characteristic Leaching Procedure). High concentrations (e.g., greater than 20%) of naturally-occurring
humic matter may also interfere with cement-based processes, but some success with higher levels of organics has been
reported using modified lime products.
Page 30
-------
APPENDIX A
TECHNICAL BASIS FOR PRESUMPTIVE REMEDIES
This Appendix summarizes the analyses that EPA conducted on Feasibility Study (FS) and Record of
Decision (ROD) data from Superfund wood treater sites, which led to establishing bioremediation, thermal
desorption, incineration, and immobilization as the presumptive remedies for wood treater sites with
contaminated soils, sediments, and sludges. The analyses consisted of the following activities:
• Identifying wood treater sites;
• Determining the frequency of technology selection for wood treater sites;
• Identifying sites for the FS/ROD analysis; and
• Conducting the FS/ROD analysis.
Results of the FS/ROD analysis, along with a technical analysis of performance data on technology
application, are part of the Administrative Record for this directive, which is available at EPA Headquarters
and the Regional Offices. These analyses provide support for the decision to eliminate the initial alternatives
identification and screening step for this site type. These analyses found that certain technologies are
appropriately screened out based on effectiveness, implementability, and/or cost. Review of technologies
against the nine remedial criteria led to elimination of additional alternatives. A discussion of each of the
analyses is provided below.
Identification of the Universe of Wood Treater Sites
EPA identified the universe of wood treater sites listed on the National Priorities List from information
contained in the following two sources: (1) Contaminants and Remedial Options at Wood Preserving Sites,
U.S. EPA, EPA/600/R-92/182,1992; and (2) Innovative Treatment Technologies: Annual Status Report (Sixth
Edition), U.S. EPA, EPA 542-R-94-005, 1994. The first source contained comprehensive lists of NPL and
non-NPL wood treater sites prior to 1992. The second source contained information, current as of 1994, on
the status of the implementation of innovative treatment technologies at a wide range of sites, including
wood treater sites. By cross-checking the information in both of these documents, an overall list of 58 NPL
wood treater sites was identified.
Frequency of Technology Selection for Wood Treater Sites
Table A-l presents the distribution of remedial technologies selected at 52 of the 58 NPL wood treater sites
(data on remedy selection were not available for the remaining six sites). These data were obtained from
the two sources cited above and EPA's Superfund Records of Decision CD-ROM data base (March 1995).
Table A-l demonstrates that the four wood treater site presumptive remedies (bioremediation, thermal
desorption, incineration, and immobilization) together were selected more often (39 out of the 50 sites for
which remedy selection information was available, or approximately 78% of the time) than the other
applicable technologies. Bioremediation, the primary presumptive remedy for treating organic contamination,
was the remedy selected more often than any other technology (18 out of the 50 sites, or approximately 36%
of the time).
Page 31
-------
APPENDIX A
TECHNICAL BASIS FOR PRESUMPTIVE REMEDIES (continued)
TABLE A-1
Remedies Selected at NPL Wood Treater Sites
Primary Technologies
Selected to Address
Contaminated Soils,
Sediments, and Sludges at
Wood Treater Sites
Bioremediation
Thermal Desorption
Incineration
Immobilization
Dechlorination
Solvent Extraction
Soil Rushing/Washing
Landfilling
Institutional
Controls/Monitoring
To Be Determined2
Total Number of
Sites Selecting
Technology1
18
3
13
13
2
1
6
4
2
2
*5 '
Remedial technology for contaminated soils, sediments, and/or sludges not yet selected.
Identification of Sites fnr the FS/ROD Analysis
Page 32
-------
APPEMD5X A
TECHNICAL BASIS FOR PRESUMPTIVE REMEDIES (continued)
• Sites were chosen to ensure a balanced distribution among the primary technologies for addressing
contaminated soils, sediments, and sludges at wood treater sites (i.e., bioremediation, thermal
desorption, incineration, immobilization, dechlorination, solvent extraction, soil flushing/washing,
landfilling, and institutional controls/monitoring); and
• Sites were chosen to ensure an even distribution in geographic location and ROD signature date.
Using these criteria, a set of 25 NPL wood treater sites was chosen for the FS/ROD analysis; this represents -
approximately 43% of the total universe of NPL wood treater sites.
FS/ROD Analysis
The FS/ROD analysis involved a review of the technology screening phase, including any pre-screening steps,
followed by a review of the detailed analysis and comparative analysis phases in each of the 25 FSs and
RODs. Information derived from each review was documented on site-specific data collection forms, which
are available for evaluation as part of the Administrative Record for this directive (available at EPA
Headquarters and the Regional Offices).
For the screening phase, the full range of technologies considered was listed on the data collection forms,
along with the key reasons given for eliminating technologies from further consideration. These reasons were
categorized according to the three initial screening criteria: cost, effectiveness, and/or implementability. The
frequency with which specific reasons were given for eliminating a technology from further consideration was
then tallied and compiled into a screening phase summary table (Table A-2).
For the detailed analysis and comparative analysis, information on the relative performance of each
technology/alternative with respect to the nine NCP criteria was documented on the site-specific data
collection forms. In most cases, several different remedial technologies were combined in the FSs and RODs
to form a remedial alternative or cleanup option. The disadvantages of a technology/alternative were then
compiled into a detailed analysis/comparative analysis summary table, under the assumption that these
disadvantages contributed to non-selection. The advantages and disadvantages associated with each cleanup
option were highlighted. Table A-3 provides the summary information for the detailed analysis and
comparative analysis phases.
Tables A-2 and A-3 demonstrate that non-presumptive remedy technologies are consistently eliminated from
further consideration in the screening phase due to effectiveness, implementability, and/or excessive costs.
In addition, the FS/ROD analysis indicates that, although certain technologies routinely passed the screening
phase, these technologies were selected infrequently because they did not provide the best overall
performance with respect to the nine criteria. This analysis (in addition to the technical background
documentation in the Administrative Record) will support a decision by site managers to bypass the
technology identification and screening step for a particular wood treater site and select one or more of the
presumptive remedies for contaminated soils, sediments, and sludges. As previously discussed, this document
and the accompanying FS/ROD analysis should be part of the Administrative Record for the site. Additional
supporting materials not found in the Regional files can be provided by Headquarters, as needed.
Page 33
-------
APPENDIX A
TABLE A-2: SUMMARY OF INITIAL SCREENING PHASE FOR WOOD TREATER SITES
Remedial Technology or Treatment
A. Restrictions/Monitoring
A. Capping
1. unspecified
2. asphalt/concrete
3. soil/bentonite/clay
4. multi-layer cover system
B. Closure-In-Place/On-Site
Encapsulation/Vaults
D. Long-Term On-Site Landfill
A. Solidification/Stabilization
- '
A. Biological Treatments
1. in situ bioremediation
2. ex situ bioremedi
treatment units)
Treatment
*^— •- •^••^-^
ng
*" "" Jf t
stem
Site
torage Pile
.andfill
' :
ion
n
n (e.g., lined land
#ofFSs
Technology
Was
Considered1
a vl , ,|t _ , , , — -
', -'
- : ,- ''?•--',
23
£ ' ' *
....> -... •>
42
5
10
13
14
10
9
16
' , {'
23
' s
54
18
15
# of FSs
Technology
Passed
_ Screening
.',.'. J. •:"-. *"• '
22
'%._ , -"; ;,
-------
APPENDIX A
TABLE A-2: SUMMARY OF INITIAL SCREENING PHASE FOR WOOD TREATER SITES
(continued)
Remedial Technology or Treatment
3. off-site landfarming
4. soil/slurry bioreactor
5. anaerobic treatment
6. other
B. Other Thermal Treatments
1. thermal desorption
2. pyrolysis
3. vitrification
4. wet air oxidation
5. infrared treatment
6. other
C. Incineration
1. on-site
2. off-site
D. Chemical Treatments
1. dechlorination
2. solvent extraction
3. other
# of FSs
Technology
Was
Considered1 •
. 4
12
4
1
49
10
9
14
5
9
2
43
23
20
30
12
14
4
# of FSs
Technology
Passed
Screening
0
5
0
0
9
5
0
2
0
2
0
26
15
11
9
4
5
0
# of FSs
Technology Was
Screened Out
4
7
4
1
40
5
9
12
5
7
2
17
8
9
21
8
9
4
# of FSs Where Criterion Contributed to Screening Out2
Cost
1
7
1
4
2
9
3
6
7
3
4
Effectiveness
2
3
4
1
23
3
5
8
3
2
2
4
3
1
13
5
. 4
4
Implementability
3
2
1
1
20
1
5
9
2
1
2
11
5
6
12
4
6
2
Page 35
-------
APPENDIX A
TABLE A-2: SUMMARY OF INITIAL SCREENING PHASE FOR WOOD TREATER SITES
(continued)
Remedial Technology or Treatment
E. Physical Treatments
1. soil flushing (HI situ)
2. soil washing (ex situ)
3. attenuation (mixing with clean soil)
4. aeration/soil venting
5. macro-encapsulation/
overpacking
6. other
V, 0$$ift0$tfafK
A. Off-Site RCRA Facility
B. Off-Site Sanitary Landfill
C. Off-Site Recycle/Reuse Facility
# of FSs
Technology
Was
Considered'
42
14
19
2
5
1
1
:
23
3
3
# of FSs
Technology
Passed
Screening
12
5
7
0
0
0
0
'
19
1
1
# of FSs
Technology Was
Screened Out
30
9
12
2
5
1
1
4
2
2
# of FSs Where Criterion Contributed to Screening Out2
Cost
5
1
2
1
1
%
3
Effectiveness
21
8
7
1
3
1
1
1
1
1
Implementability
13
5
3
2
2
1
2
1
1
1 Because several specific technologies within a general technology group (e.g., capping: unspecified capping, asphalt/concrete caps, soil/bentonite/clay caps, and multi-layer cover
systems) were considered for each site, the total number of FSs in which a technology group was considered may be greater than 25.
2 FSs may indicate more than one criterion for screening out a technology. Also, some FSs did not fully explain the criteria for screening out a technology. Therefore, the totals
for these screening criteria may not be equal to the number of FSs in which a technology was screened out.
Page 36
-------
APPENDIX A
TABLE A-3: SUMMARY OF DETAILED ANALYSIS PHASE FOR WOOD TREATER SITES
Remedial Technology or
Treatment
•••; '
"• 5 •v ••
*U l££u£s€»iv:Iuii<~l
Cfcpwfe
A. Restrictions/
Monitoring
3l»» Cft^^£3$l$$$&t •• •"'
A, Capping
1. unspecified
2. asphalt/
concrete
3. soil/bentonite/
clay
4. multi-layer cover
system
B. Closure-In-
Place/On-Site
Encapsulation/
Vault
G. Temporary On-Site
Storage Pile
D. Long-Term On-Site
Landfill
#of
FSs/RODs
Technology
Was
Considered1
.
22
' s S
,_ 28
5
4
8
11
4
7
9
#of
FSs/RODs
Technology
Was
Selected2
',"
•.
22
'
13
2
2
4
5
3
6
1
#of
FSs/RODs
Technology
Was Not
Selected
j
'
0
' / '
15
3
2
4
6
1
1
8
# of FSs/RODs Where Criterion Contributed to Non-Selection3
Overall
Protectiveness
;
'
*
; '
7
1
1
2
3
1
1
Compliance
w/Federal
ARARs
'
'
%
3
1
1
1
2
Reduction
of
Toxicity,
Mobility,
& Volume
: '
•f ' ',
- - \
12
2
2
3
5
1
1
3
Long-Term
Effectiveness/
Permanence
'
* f
f '.
7
1
1
2
3
1
1
Short-Term
Effectiveness
i - ':
•••. '•
', % '•''
," , '••
1
1
1
Implementability
": '* •• * <
•• 'I s' ' '•
: f % *"
f ^
3
1
2
1
4
Cost
,' :
' * ;:
- ;
! '' ' ' '•'•
3
1
1
1
1
2
Page 37
-------
APPENDIX A
TABLE A-3: SUMMARY OF DETAILED ANALYSIS PHASE FOR WOOD TREATER SITES
(continued)
Remedial Technology or
Treatment
Jit IffltHobifeafion
A. Solidification/
Stabilization
W, Treatment:,
A. Biological
Treatments
1. in sitii
bioremediation
2. ex situ
bioremediation
3. soil/slurry
bioreactor
B. Other Thermal
Treatments
1. thermal desorption
2. vitrification
3. infrared treatment
#of
FSs/RODs
Technology
Was
Considered1
15
18
5
8
5
9
5
2
2
#of
FSs/RODs
Technology
Was
Selected2
'
11
'
9
2
5
2
2
2
0
0
#of
FSs/RODs
Technology
Was Not
Selected
,
4
%
9
3
3
3
7
3
2
2
# of FSs/RODs Where Criterion Contributed to Non-Selection3
Overall
Protectiveness
•. :
'•••
1
1
Compliance
w/Federal
ARARs
,
Reduction
of
Toxicity,
Mobility,
& Volume
3
2
1
1
2
2
Long-Term
Effectiveness/
Permanence
%
1
,,
5
3
2
2
2
Short-Term
Effectiveness
/ ' :
1
-------
APPENDIX A
TABLE A-3: SUMMARY OF DETAILED ANALYSIS PHASE FOR WOOD TREATER SITES
(continued)
Remedial Technology or
Treatment
C. Incineration
1. on-site
2. off-site,
D. Chemical Treatment
T. solvent extraction
2. dechlorination
E. Physical Treatment
1. soil flushing (in
situ)
2. soil washing
(ex situ)
#of
FSs/RODs
Technology
Was
Considered'
26
15
11
9
5.
4
12
5
7
#of
FSs/RODs
Technology
Was
Selected2
7
3
4
4
1
3
6
1
5
#of
FSs/RODs
Technology
Was Not
Selected
19
12
7
5
4
1
6
4
2
# of FSs/RODs Where Criterion Contributed to Non-Selection3
Overall
Protectiveness
1
1
1
1
Compliance
w/Federal
ARARs
1
1
Reduction
of
Toxicity,
Mobility,
& Volume
3
2
1
2
1
1
1
1
Long-Term
Effectiveness/
Permanence
4
2
2
3
3
Short-Term
Effectiveness
7
4
3
Implementability
12
6
6
2
2
4
3
1
Cost
14
8
6
2
2
1
1
Page 39
-------
APPENDIX A
TABLE A-3: SUMMARY OF DETAILED ANALYSIS PHASE FOR WOOD TREATER SITES
(continued)
Remedial Technology or
Treatment
V. Oft&Ite Option*
A. Off-Site RCRA
Landfill
B. Off-Site Sanitary
Landfill
C. Off-Site
Reclamation/
Recycling
-_.:• — — J
#of
FSs/RODs
Technology
Was
Considered1
^^^j, I,, ——
"•• ... .'.. .,
19
1
1
#of
FSs/RODs
Technology
Was
Selected2
LI mni. i FT*"" '"ml
10
0
1
#of
FSs/ROF
Technolt
Was Not
Selected
'Si
-9
1
0
——==========sss========ss=====^^
# of FSs/RODs Where Criterion Contributed to Non-Selection3
Overall
Protectiveness
— '"/ f ,,,,%,\
2
Compliance
w/Federnl
ARARs
& 5 "'* f/fj
1
Reduction
of
Toxicity,
Mobility,
& Volume
\"*
1
Long-Term
Effectiveness/
Permanence
1
Short-Term
Effectiveness
/*s f f
=====
Implementability
;, f, -/:';
6
•^^"^ —
-
Cost
2
1 Because several specific technologies within a general technology group (e.g., capping: unspecified capping, asphalt/concrete caps, soil/bentonite/clay caps, and multi-layer cover systems) were considered
for each site, the total number of FSs/RODs in which a technology group was considered may be greater than 25.
2 The total number of remedial technologies selected is greater than 25 because treatment trains consisting of several different technologies were selected at most sites For example ^ selection; *
an^lal! renSy lay nave included the selection of institutional controls to control direct contact exposure, bioremediation to treat organic contaminat.on (mcludmg so,l washmg), and .mmob.hzat.on
to address inorganic contamination.
^ Information on state and community concerns was not included in this analysis because FSs do not contain this information, and RODs f^^^S^SS
concurrence letters and responsiveness summaries). FSs and RODs may indicate more than one criterion for non-selecuon of a technology. Therefore, the totals for these n
not be equal to the number of FSs/RODs in which a technology was not selected.
may
Page 40
-------
APPENDIX B
EVALUATION OF SELECTION CRITERIA FOR TECHNOLOGIES USED TO TREAT CONTAMINATED
SOILS, SEDIMENTS, AND SLUDGES AT WOOD TREATER SITES:
BIOREMEDIATION
'••if.
CRITERIA
Overall Protection of
Human Health and
"'-• the Environment
Provides protection by'
reducing
concentrations of
organic contaminants
in soils, sediments, and
sludges.
Ex situ bioremediation
requires measures to
protect workers and
the community during
excavation, handling,
and treatment.
Does not impact the
local environment with
the proper
implementation of
erosion/sediment
control measures.
Compliance with
ARARs
Operation must
comply with all federal
and state regulations
that are identified as
ARARs.
Requires compliance
with RCRA removal,
treatment,
transportation, and
land disposal
regulations, if RCRA
is determined to be an
ARAR.
Requires compliance
with CERCLA off-site
rule (if off-site
treatment, storage, or
disposal is used).
Long-Term
Effectiveness and
Permanence
Residual
contamination
following treatment
may require use of
capping and/or
institutional controls.
Residual
contamination may
migrate.
Hazardous substances
left in place will
require a five-year
review.
Bioremediation
systems may require
lengthy operation, in
addition to long-term
maintenance of cap
integrity (if capping is
implemented).
Reduction of Toxicity,
Mobility, or Volume
Through Treatment
May reduce toxicity,
mobility, and volume
through degradation of
organic contaminants;
however, if bulking
agents are added,
volume may not
necessarily be reduced.
If used in conjunction
with capping,
minimizes mobility.
Short-Term Effectiveness
Microbial degradation is a
relatively slow process that
is highly site-specific and is
affected by a multitude of
factors. Some of these
factors (e.g., electron
acceptor and nutrient
availability, and pH) may
need to be examined in
bench-scale studies during
the design phase of site
remediation to maximize
aerobic activity and
minimize process
interferences.
Ex situ bioremediation
presents potential short-
term risks to workers and
community from air
releases during excavation
and treatment; requires air
monitoring to address these
short-term risks.
Implementability
Requires relatively
simple technologies;
easy to construct and
operate.
May require bench-
and/or pilot-scale
studies during the
design phase. Pilot-
scale studies in the
field are almost
always required
before full-scale
implementation.
Easy to economically
maintain treatment
until cleanup levels
are achieved.
Size of site may limit
capability to perform
some types of ex situ
bioremediation.
Cost1
In situ $50 - $100
per cubic
yard of
soil,
sediment,
or sludge.
Ex situ $50 - $150
per cubic
yard of
soil,
sediment,
or sludge;
or $40 -
$125 per
ton of soil,
sediment,
or sludge.
1 Actual cost of a remediation technology is highly site-specific and dependent upon target cleanup levels of contaminants, soil characteristics, and the design and operation of the remediation technology
used.
Page 41
-------
APPENDIX B
EVALUATION OF SELECTION CRITERIA FOR TECHNOLOGIES USED TO TREAT CONTAMINATED
SOILS, SEDIMENTS, AND SLUDGES AT WOOD TREATER SITES:
BIOREMEDIATION (continued)
CRITERIA
Overall Protection of
Human Health and
the Environment
In situ bioremediation
may not be feasible
for the treatment of.
subsurface soils,
sediments, and sludges
(depending upon
variables such as
contaminant type, soil
type, depth to
contamination, etc.).
A simple cap, in
conjunction with
bioremediation,
provides protection by
reducing and/or
controlling erosion and
direct contact
exposure to residual
contamination.
Compliance with
ARARs
Requires compliance
with'Hazardous
Materials
Transportation Act
regulations (if off-site
treatment is used).
Requires compliance
with location-specific
ARARs.
Ex situ bioremediation
may need emission
controls to ensure
compliance with air
quality standards
during excavation and
treatment.
Long-Term
Effectiveness and
Permanence
In situ process
generates little, if any,
toxic waste streams
that need to be
disposed; ex situ may
generate such streams.
Reduction ofToxicity,
Mobility, or Volume
Through Treatment
-•*
Short-Term Effectiveness
Where it is feasible, in situ
bioremediation requires the
least soil disturbance and,
therefore, presents the least
short-term risks.
Involves potential short-
term risks from handling
and transporting waste (if
off-site treatment is used).
Implementability
Cost1
1 Actual cost of a remediation technology is highly site-specific and dependent upon target cleanup levels of contaminants, soil characteristics, and the design and operation of the remediation technology
used.
Page 42
-------
APPENDIX B
EVALUATION OF SELECTION CRITERIA FOR TECHNOLOGIES USED TO TREAT CONTAMINATED
SOILS, SEDIMENTS, AND SLUDGES AT WOOD TREATER SITES:
THERMAL DESORPTION
CRITERIA
Overall Protection of
Human Health and the
Environment
Provides both short-
and long-term
protection by
eliminating exposure to
organic contaminants in
soils, sediments, and
sludges.
Prevents further
ground-water
contamination and off-
site migration.
Requires measures to
protect workers and the
community during
excavation, handling,
and treatment.
Compliance with ARARs
Operation and design must
comply with all federal and
state ARARs concerning
hazardous waste treatment
facilities.
Requires compliance with
RCRA removal, treatment,
transportation, and land
disposal regulations, if
RCRA is determined to be
an ARAR.
Requires compliance with
CERCLA off-site rule (if
off-site treatment, storage, or
disposal is used).
Long-Term Effectiveness
and Permanence
Effectively removes source
of contamination.
Has been demonstrated as
an effective technique for
removing and
concentrating organic
contaminants in soils,
sediments, and sludges.
Would involve some
treatment or disposal of
residuals in addition,
generally through use of
carbon adsorption/
regeneration or disposal.
Eliminates risks associated
with direct contact or
migration of wastes.
Reduction of
Toxicity, Mobility,
or Volume Through
Treatment
Significantly reduces
toxicity, mobility,
and volume of
contaminants
through treatment.
Short-Term
Effectiveness
Presents potential
short-term risks to
workers and
community from
fugitive emissions
during excavation and
treatment (if on-site
treatment is used).
Requires air
monitoring to address
these short-term risks.
Involves potential
short-term risks from
handling and
transporting waste (if
off-site treatment is
used).
Requires relatively
short time frame to
achieve cleanup
levels.
Implementability
Substantive permit
requirements must be
addressed.
Mobile treatment
units are readily
available.
Limited off-site
treatment capacity
exists.
Used successfully at
other Superfund sites
to treat organic
contaminants in soils,
sediments, and
sludges.
Public may oppose
technology, viewing it
as similar to
incineration.
Cost1
$150 - $400 per
ton of soil,
sediment, or :
sludge,
excluding
excavation,
material
handling, or
disposal costs.
1 Actual cost of a remediation technology is highly site-specific and dependent upon target cleanup levels of contaminants, soil characteristics, and the design and operation of the remediation technology
used.
Page 43
-------
APPENDIX B
EVALUATION OF SELECTION CRITERIA FOR TECHNOLOGIES USED TO TREAT CONTAMINATED
SOILS, SEDIMENTS, AND SLUDGES AT WOOD TREATER SITES:
THERMAL DESORPTION (continued)
CRITERIA
Overall Protection of
Human Health and the
Environment
Compliance with ARARs
Requires compliance with
Hazardous Materials
Transportation Act
regulations (if off-site
treatment is used).
Requires compliance with
location-specific ARARs.
Emission controls may be
needed to ensure compliance
with air quality standards
during excavation and
treatment.
EPA's Draft Combustion
Strategy is a TBC (e.g., for
conducting risk assessments,
etc.)
Long-Term Effectiveness
and Permanence
Reduction of
Toxicity, Mobility,
or Volume Through
Treatment
Short-Term
Effectiveness
Implementability
Requires engineering
measures to control
air emissions, fugitive
dust, runoff, erosion,
and sedimentation.
Cost1
1 Actual cost of a remediation technology is highly site-specific and dependent upon target cleanup levels of contaminants, soil characteristics, and the design and operation of the remediation technology
used.
Page 44
-------
APPENDIX B
EVALUATION OF SELECTION CRITERIA FOR TECHNOLOGIES USED TO TREAT CONTAMINATED
SOILS, SEDIMENTS, AND SLUDGES AT WOOD TREATER SITES:
INCINERATION
Overall Protection of
Human Health and
the Environment
Provides both short-
and long-term
protection by
permanently destroying
organic contaminants
in soils, sediments, and
sludges.
Prevents further
ground-water
contamination and off-
site migration.
Requires measures to
protect workers and
the community during
excavation, handling,
and treatment.
CRITERIA
Compliance with ARARs
Operation and design must
comply with air federal and
state ARARs concerning
hazardous waste treatment
facilities.
Requires compliance with
RCRA removal, treatment,
transportation, and land
disposal regulations, if
RCRA is determined to be
an ARAR.
Requires compliance with
CERCLA off-site rule (if off-
site treatment, storage, or
disposal is used).
Must meet Boiler and
Industrial Furnace (BIF)
regulations, which can be
more restrictive than RCRA.
Long-Term
Effectiveness and
Permanence
Effectively destroys
nearly all
contamination.
Is a well-demonstrated
technique for treating
organic contaminants
in soils, sediments, and
sludges.
Eliminates risks
associated with direct
contact or migration
of wastes.
Generates little, if any,
toxic residues.
Reduction of Toxicity,
Mobility, or Volume
Through Treatment
Significantly reduces
toxicity, mobility, and
volume of
contaminants through
treatment.
Short-Term
Effectiveness
Presents potential
short-term risks to
workers and
community from
fugitive emissions
during excavation and
treatment (if on-site
treatment is used).
Requires air
monitoring to address
these short-term risks.
Involves potential
short-term risks from
handling and
transporting waste (if
off-site treatment is
used).
Requires relatively
short time frame to
achieve cleanup levels.
Implementability
Construction and
substantive permit
requirements of on-
site incinerators may
be somewhat difficult
to meet.
Mobile incinerators
are readily available;
these use common
procedures and
equipment.
Limited off-site
incineration capacity
exists.
Used successfully at
other Superfund sites
to treat organic
contaminants in soils,
sediments, and
sludges.
Cost1
$150 - $400 per
r
ton of soil,
sediment, or
sludge, excluding
excavation,
material handling,
OJ
or disposal costs. •:
1 Actual cost of a remediation technology is highly site-specific and dependent upon target cleanup levels of contaminants, soil characteristics, and the design and operation of the remediation technology-
Page 45
-------
APPENDIX B
EVALUATION OF SELECTION CRITERIA FOR TECHNOLOGIES USED TO TREAT CONTAMINATED
SOILS, SEDIMENTS, AND SLUDGES AT WOOD TREATER SITES:
INCINERATION (continued)
I
CRITERIA
Overall Protection of
Human Health and
the Environment
Compliance with ARARs
Requires compliance with
Hazardous Materials
Transportation Act
regulations (if off-site
treatment is used).
Requires compliance with
location-specific ARARs.
Emission controls may be
needed to ensure compliance
with air quality standards
during excavation and
treatment
EPA's Draft Combustion
Strategy is a TBC (e.g., for
conducting risk assessments,
etc.)
Long-Term
Effectiveness and
Permanence
Reduction of Toxicity,
Mobility, or Volume
Through Treatment
Short-Term
Effectiveness
=========s==
Implementability
Public opposition may
make this technology
infeasible
Requires a trial burn
to demonstrate
destruction efficiency
and define operating
parameters (if on-site
treatment is used).
Requires coordination
with state and local
officials to select
transportation routes
(if off-site treatment is
- - ~ •••
Cost1
:======
' Actual cost of a remediation technology is highly site-specific and dependent upon target cleanup levels of contaminants, soil characteristics, and the designed operation of the remediation technology
used.
Page 46
9
-------
APPENDIX B
EVALUATION OF SELECTION CRITERIA FOR TECHNOLOGIES USED TO TREAT CONTAMINATED
SOILS, SEDIMENTS, AND SLUDGES AT WOOD TREATER SITES:
IMMOBILIZATION
Overall Protection of
Human Health and
the Environment
Provides both short-
and long-term
protection by
containing
contaminants in a
fixed-soil/sediment/
sludge mass.
Reduces the potential
for further ground-
water contamination
and off-site migration.
Reduces potential
risks associated with
inhalation, dermal
contact, and ingestion
of contaminated soils,
sediments, and
sludges.
CRITERIA
Compliance with
ARARs
Operation must
comply with all federal
and state ARARs.
Requires compliance
with RCRA removal,
treatment,
transportation, and
land disposal
regulations, if RCRA
is determined to be an
ARAR.
Requires compliance
with CERCLA off-site
rule (if off-site
treatment, storage, or
disposal is used).
Long-Term
Effectiveness and
Permanence
Represents a long-term
solution that effectively
reduces and/or
eliminates the mobility
of hazardous
substances into the
environment.
Has been
demonstrated as an
effective technique for
treating inorganic
contaminants
(primarily metals, such
as chromium and
arsenic) in soils,
sediments, and sludges.
Reduction of Toxicity,
Mobility, or Volume
Through Treatment
Significantly reduces
the mobility of
inorganic contaminants
(and non-volatile
organics, to some
extent) by chemically
binding and
encapsulating them.
Does not reduce
volume or toxicity of
contaminants. Volume
may increase 30-50%
through the mixing of
the soil/sediment/
sludge with fixative
agents.
Short-Term
Effectiveness
Presents potential
short-term risks to
workers and
community from air
release during
excavation and
treatment (if on-site
treatment is used).
Involves potential
short-term risks from
handling and
transporting waste (if
off-site disposal is
used).
Requires relatively
short time frame to
achieve cleanup levels.
Implementability
Requires relatively
simple technologies;
easy to construct and
operate.
Requires treatability
testing.
Used successfully at
other Superfund sites
to treat inorganic
(primarily metals)
contaminants in soils,
sediments, and sludges.
Cost1
$75 - $400 per ton of
soil, sediment, or
sludge (for on-site
treatment).
$100 - $500 per ton of
soil, sediment, or
sludge (for off-site
disposal).
^Actual cost of a remediation technology is highly site-specific and dependent upon target cleanup levels of contaminants, soil characteristics, and the design and operation of the remediation technology
Page 47
-------
APPENDIX B
EVALUATION OF SELECTION CRITERIA FOR TECHNOLOGIES USED TO TREAT CONTAMINATED
SOILS, SEDIMENTS, AND SLUDGES AT WOOD THEATER SITES:
IMMOBILIZATION (continued)
CRITERIA
Overall Protection of
Human Health and
the Environment
Requires measures to
protect workers and
the community during
excavation, handling,
and treatment.
Lower portions of the
soil profile are often
untreated.
Compliance with
ARARs
Requires compliance
with Hazardous
Materials
Transportation Act
regulations (if off-site
disposal is used).
Requires compliance
with location-specific
ARARs.
Emission controls may
be needed to ensure
compliance with air
quality standards
during excavation and
treatment.
Long-Term
Effectiveness and
Permanence
Requires air and
ground-water
monitoring to confirm
long-term effectiveness.
Requires proper
management and/or
institutional controls to
address any residual
risks associated with
direct contact.
Reduction of Toxicity,
Mobility, or Volume
Through Treatment
Short-Term
Effectiveness
Short-term
effectiveness
maintained through
strict environmental
controls.
Implementability
Cost1
1 Actual cost of a remediation technology is highly site-specific and dependent upon target cleanup levels of contaminants, soil characteristics, and the design and operation of the remediation technology
used.
Page 48
-------
GLOSSARY
Action Memorandum — A document that provides a concise written record of the decision selecting a
removal action. It describes the site's history, current activities, and health and environmental threats;
outlines the proposed actions and costs; and documents approval of the proposed action by the proper
EPA Headquarters or Regional authority.
Administrative Record — A formal record established by the lead agency, it contains the documents that
form the basis for the selection of a response action (e.g., analysis report, Feasibility Study, Record of
Decision, Directives, etc.).
Applicable or Relevant and Appropriate Requirements (ARARs) —Applicable requirements are cleanup
standards, standards of control, and other substantive requirements, criteria, or limitations promulgated
under federal environmental or facility siting laws that specifically address a hazardous substance,
pollutant, contaminant, remedial action, location, or other circumstance found at a CERCLA site.
Relevant and appropriate requirements are cleanup standards, standards of control, and other substantive
requirements, criteria, or limitations promulgated under federal environmental or facility siting laws that,
while not "applicable" to a hazardous substance, pollutant, contaminant, remedial action, location, or other
circumstances at a CERCLA site, address problems or situations sufficiently similar to those encountered
at the CERCLA site and are well-suited to the particular site.
Engineering Evaluation/Cost Analysis (EE/CA) — Required for non-time-critical removal actions, the
EE/CA contains information on site characteristics, removal action objectives, and removal action
alternatives. ]t is intended to identify the objectives of the removal action and to analyze the various
alternatives that may be used to satisfy these objectives for cost, effectiveness, and implementability. The
EE/CA process includes: conducting a removal site evaluation, notifying PRPs of their liability, preparing
an EE/CA approval memorandum, and preparing a study documenting the removal action options.
Although an EE/CA is similar to the RI/FS conducted for remedial actions, it is less comprehensive. The
EE/CA is part of the Administrative Record file and is subject to the public comment and
comment/response requirements for the Administrative Record.
Feasibility Study (FS) — A study undertaken by the lead agency to develop and evaluate options for
remedial design. The FS emphasizes data analysis and is generally performed concurrently and in an
interactive fashion with the Remedial Investigation (RI), using data gathered during the RI.
Hazard Ranking System (HRS) — The method used by EPA to evaluate the relative potential of
hazardous substance releases to cause health or safety problems, or ecological or environmental damage.
Innovative Treatment Technologies — Technologies that have been tested, selected, or used for the
treatment of hazardous substances or contaminated materials but lack well-documented cost and
performance data under a variety of operating conditions.
National Priorities List rNPL> — The list compiled by EPA, pursuant to CERCLA section 105, of
hazardous substance releases in the United States that are priorities for long-term remedial evaluation and
response.
On-Scene Coordinator COSO — The federal official predesignated; by EPA or the U.S. Coast Guard to
coordinate and direct federal responses under Subpart D of the NCP, or the official designated by the lead
agency to coordinate and direct removal actions under Subpart E of the NCP.
Preliminary Remediation Goals (PRGs) - Initial cleanup goals developed as part of the overall remedial
action objectives. PRGs are established and refined based on a variety of information, including ARARs
Page 49
-------
GLOSSARY
(continued)
and TBCs, the baseline risk assessment, anticipated future land use(s) of the site, and technical, exposure,
and uncertainty factors.
Principal Threats - Principal threats include liquids, areas contaminated with high concentrations of toxic
compounds, and highly mobile materials.
Record of Decision (ROD) — The final remedial action plan for a site or operable unit, which summarizes
problems, alternatives, remedies, and the selected remedy. The ROD also includes the rationale for the
selection of the final remedy, and explains how the selected remedy meets the nine evaluation criteria
stated in the NCP.
Remedial Investigation (RI) — A process undertaken by the lead agency to determine the nature and
extent of the problem presented by a release. The RI emphasizes data collection and site characterization,
and is generally performed concurrently and in an interactive fashion with the Feasibility Study.
Remedial Project Manager (RPM) — The official designated by the lead agency to coordinate, monitor, or
direct a remedial action under Subpart E of the NCP.
Remedial Site Evaluation — A process undertaken by the lead agency to collect data, as required, and
evaluate a release or threat of release of hazardous substances, pollutants, or contaminants. The
evaluation may consist of two steps: a preliminary assessment (PA) and a site inspection (SI).
Removal Site Evaluation — A process undertaken by the lead agency to identify the source and nature of a
release or threat of release; it may include a removal preliminary assessment and, if warranted, a removal
site inspection.
Risk Assessment — The qualitative and/or quantitative evaluation performed in an effort to define the risk
posed to human health and/or the environment by the cumulative presence or potential presence and/or
use of specific pollutants.
Superfund Accelerated Cleanup Model (SACM) - The purpose of SACM is to make hazardous waste
cleanups more timely and efficient. This will be accomplished through a greater focus on the front end of
the process and better integration of all Superfund program components. The approach involves: (1) a
continuous process for assessing site-specific conditions and the need for action; (2) cross-program
coordination of response planning; (3) prompt risk reduction through early action (removal or remedial);
and (4) appropriate cleanup of long-term environmental problems.
To Be Considereds (TBCs) — Non-promulgated advisories or guidance issued by federal or state
governments that are not legally binding and do not have the status of potential ARARs. In many
circumstances, TBCs will be considered along with ARARs as part of the risk assessment and may be used
in determining the necessary level of cleanup for protection of health or the environment.
Treatability Studies — Preliminary studies in which a hazardous waste is subjected to a treatment process
to determine if the waste is amenable to the process, what pretreatment activities are necessary, what the
optimal process options are, and what is the efficiency of the process.
Page 50
-------
REFERENCES
1- Approaches for Remediation of Uncontrolled Wood Preserving Sites. EPA/625/7-90/011, US EPA,
Office of Environmental Research Information, Cincinnati, OH, November 1990.
2- Bioremediation in the Field Search System (SPSS'). Version 1.0., US EPA, available through CLU-IN
Bulletin Board (301-589-8366).
3- CERCLA Compliance with Other Laws Manual: Interim Final. EPA/540/G-89/006, US EPA, OERR,
August 1988.
4- CERCLA Compliance with Other Laws Manual: Part II. Clean Air Act and Other Environmental
Statutes and State Requirements. EPA/540/G-89/009, US EPA, OSWER, August 1989.
5- Community Relations in Superfund: A Handbook (Interim Guidance^. OERR/HSCD Publication
9230.0-03B, US EPA, June 1988.
6- Considerations in Ground Water Remediation at Superfund Sites. OSWER Directive 9355.4-03, US
EPA, October 18, 1989.
7- Considerations in Ground-Water Remediation at Superfund Sites and RCRA Facilities - Update
OSWER Directive 9283.1-06, US EPA, May 27, 1992.
8. Contaminants and Remedial Options at Wood Preserving Sites. EPA/600/R-92/182, US EPA, ORD
RREL, October 1992.
9. "Creosote Contaminated Sites — Their Potential for Bioremediation," Environmental Science and
Technology. Vol. 23. No. 10. pp. 1197-1201. 1989.
10- Dense Nonaqueous Phase Liquids - A Workshop Summary. Dallas. Texas. April 16-18. 1991 ORD
Publication EPA/600/R-92/030, 1992.
11- DNAPL Site Evaluation. EPA/600/R-93/022, Cohen, R.M., and J.W. Mercer, 1993.
12- Estimating Potential for Occurrence of DNAPL at Superfund Sites. OSWER Publication 9355 4-07FS
US EPA, 1992. ' '
13- Evaluation of the Likelihood of DNAFL Presence at NPL Sites. National Results. OSWER
Publication 9355.4-13, EPA/540/R-93/073, US EPA, September 1993.
14- Field and Laboratory Evaluation of Petroleum Land Treatment System Closure. NTIS #PB 86-130
564/AS, US EPA, 1986.
15- Ground Water Issue: Dense Nonaqueous Phase Liquids. EPA/540/4-91/002, US EPA, 1991.
16. Guidance for Conducting Remedial Investigations and Feasibility Studies CRI/FSst Under CERCLA.
EPA/540/6-89/004, OERR Publication 9355.3-01, US EPA, October 1988.
17- Guidance for Evaluating technical Impracticability of Ground-Water Restoration OSWER Directive
9234.2-25, EPA/540/R-93/080, US EPA, September 1993.
18- Guidance Manual on Hazardous Waste Land Treatment/Post-Closure 40 CFR Part 265 US EPA.
1987. ' ~ : '
Page 51
-------
REFERENCES
(continued)
19. Guidance on Conducting Non-Time-Critical Removal Actions Under CERCLA, EPA/540/R-93/057,
OERR Publication 9360.0-32, US EPA, August 1993.
20. Guidance on Remedial Actions for Contaminated Ground Water at Superfund Sites. OSWER
Directive 9283.1-2, EPA/540/G-88/003, US EPA, December 1988.
21. Guide for Conducting Treatabilitv Studies Under CERCLA: Biodegradation Remedy Screening -
Interim Guidance. EPA/540/R-93/519a, US EPA, August 1993.
22. Guide for Conducting Treatabilitv Studies Under CERCLA: Thermal Desorption Remedy Selection -
Interim Guidance. EPA/540/R-92/074A, US EPA, September 1991.
23. Guide to Principal Threat and Low-Level Wastes, Superfund Publication 9380.3-06FS, US EPA, 1991.
24. Guide to Treatment for Hazardous Wastes at Superfund Sites. EPA/540/2-89/052, US EPA, Office of
Environmental Engineering and Technology Development, March 1989.
25. "Incineration of Hazardous Waste: A Critical Review Update," International Journal of Air Pollution
Control and Hazardous Waste Management, Vol. 43, pp. 25-73, January 1993.
26. Innovative Treatment Technologies: Overview and Guide to Information Sources, EPA/540/9-91/002,
US EPA, OSWER, TIO, October 1991.
27. Land Use in the CERCLA Remedy Selection Process. OSWER Directive 9355.7-04, US EPA, May 25,
' 1995.
28. Mobile/Transportable Incineration Treatment Engineering Bulletin. EPA/540/2-90/014, US EPA,
February 1990.
29. Mobility and Degradation of Residues at Hazardous Waste Land Treatment Sites at Closure.
EPA/600/2-90/018, US EPA, April 1990.
30. Notice of Availability with Request for Comment on Draft Soil Screening Guidance. 59 Federal
Register 67706, December 30, 1994.
31. Presumptive Remedies: Policies and Procedures. OERR Publication 9355.0-47FS, US EPA,
September 1993.
32. Presumptive Remedies: Site Characterization and Technology Selection For CERCLA Sites With
Volatile Organic Compounds In Soils. OSWER Directive 9355.0-48FS, EPA/540/F-93/048, US EPA,
September 1993.
33. Presumptive Remedy for CERCLA Municipal Landfill Sites. OSWER Directive 9355.0-49FS,
EPA/540/F-93/035, US EPA, September 1993.
34. Removal Program Representative Sampling Guidance, Volume 1: Soil. OERR Publication 9360.4-10,
US EPA, November 1991.
35. Risk Assessment Guidance for Superfund. Volume 1: Human Health Evaluation Manual. Part A,
Interim Final. OERR/HSED Publication 9285.7-01B, US EPA, December 1989.
Page 52
-------
REFERENCES
(continued)
36- Risk Assessment Guidance for Superfimd. Volume 2: Environmental Evaluation Manual. Interim
Final. Part A. OERR/HSED Publication 9285.7-01A, US EPA, March 1989.
37- Strategy for Hazardous Waste Minimization and Combustion. EPA/530/R-94/044, US EPA, November
1994. " .
38- Suggested ROD Language for Various Ground Water Remediation Options. OSWER Directive
9283.1-03, US EPA, October 10, 1990.
39. Superfund LDR Guide #6A. Obtaining a Soil and Debris Treatabilitv Variance for Remedial Actions
OSWER Publication 9347.3-06FS, US EPA, September 1990. '
40- Superfund LDR Guide #6B. Obtaining a Soil and Debris Treatabilitv Variance for Removal Actions
OSWER Publication 9347.3-06BFS, US EPA, September 1990. '
41- s"Perrund Removal Procedures.- guidance on the Consideration of ARARs During Removal Actions
OSWER Publication 9360.3-02, US EPA, August 1991. ~~~ '
42- Superfund Removal Procedures: Public Participation Guidance for On-Scene Coordinators:
Community Relations and the Administrative Record. OERR Publication 9360.3-05, US EPA, June
43- Technology Selection Guide for Wood Treater Sites. OERR Publication 9360.0-46FS, US EPA, May
44 Thermal Desorntion Treatment Engineering Bulletin. EPA/540/2-91/008, US EPA, February, 1991.
Page 53
-------
-------
Figure 1: Decision Tree for Techn
Review
presumptive
remedies and
their associated
performance
efficiency
ranges.
1
Set PRGs, taking
into
consideration
performance
efficiencies of
the presumptive
remedies and
anticipated
future land use.
V
Prepare matrix
of proposed
presumptive
remedy options
and associated
data. Present
information to
public.
i
Evaluate the
public reaction
to the
presumptive
remedy options.
Are creosote,
PCP, or CCA
present at this
Review advantages/ limitations
table for presumptive remedies.
See Table 2.
0
Initiate early PRP, :
state, and community
involvement
to develop reasonable
assumptions for
anticipated
future land use and
to evaluate if the
presumptive remedy
approach is appropriate.
Assemble
Administrative
Record.
5. ,'
Establish remedial action
objectives (including land
use assumptions) and set
PRGs.
Conduct
characterize
Refine PRGs.
Is there a need for
further action?
Proceed*
technology ass
andrevic
"Practic
Considers ti'
-------
ology Selection at Wood Trcater Sites
Proceed with ROD or Action Memo
If only inorganic contamination is present, follow Path A. If only
organic contamination is present, follow Path B. If both
inorganic and organic contamination are present, follow Paths
A and B concurrently.
-------
4
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Publication 9203.1-021
May 1992
Presumptive Remedies for Wood Treatment
Superfund Revitahzation Activity
Office of Emergency and Remedial Response
Emergency Response Division OS-210
Intermittent Bulletin
Volume 1 Number 2
The Presumptive Remedy Selection Initiative
Since Superfund's inception in 1980, the removal and remedial programs have found that certain categories of sites have
similar characteristics, such as the types of contaminants present, past industrial use. or the environmental media that are
affected. Based on a wealth of information acquired from evaluating and cleaning up these sites, Superfund is undertaking
an initiative to develop presumptive remedies that are appropriate for specific types of sites, contaminants, or both. This
initiative is part of a larger program, known as the Superfund Accelerated Cleanup Model (SACM), which is designed to
speed all aspects of the Superfund clean-up process.
The objective of the presumptive remedies initiative is to use clean-up techniques shown to be effective in the past at similar
sites in the future. The use of presumptive remedies will streamline site studies and removal and remedial clean-up actions,
thereby improving consistency, reducing costs, and increasing the speed with which hazardous waste sites are remediated.
Why Wood Treatment Sites?
Our removal and remedial programs
have worked at almost 90 wood-treat-
ment sites, many of them on the
National Priorities List (N'PL),
gaining a great deal of data and
experience in the process. Three
primary types of contaminants, in-
cluding dioxin, usually predomi-
nate at these sites. The facilities
tend to be similar. And EPA knows
a great deal about assessing such
sites, handling the contaminants,
tind, ultimately, disposing of wood-treatment waste. The
Agency's Office of Research and Development (ORD) has
also extensively studied these sites. With all this accumu-
lated experience and information, Superfund is ready to
establish presumptive remedies that will standardize rem-
edv selection for contaminated wood-treatment sites.
What Are the Components of the Presumptive
Remedy Initiative?
iie wood-treatment presumptive rerqt^dy initiative has
rive components:
Technology Selection Matrix. This will be a guide to
the clean-up technologies known to be appropriate
for wood-treatment sites cross-tabulated with the
factors to be considered in selecting remedies.
The matrix is being developed by the Office
of Emergency and Remedial Response's
Environmental Response Team.
• ORD Guidance. Currently in
draft form, this document will
evaluate the effectiveness of vari-
ous technologies on the types of
wastes commonly found at wood-
treatment sites. The Technology
Selection Matrix will complement
this guidance.
Expert Teams. The Office of Emergency and Reme-
dial Response (OERR) will establish a team of wood-
treatment site experts who can help evaluate sites
and aid in making decisions on appropriate clean-up
methodologies.
Computer-Assisted Remedy Selection. Currently
under development is a computer program that will
provide appropriate remedy information based on
site characteristics. Although not a substitute for
expert decision-making, the program will lead users
through the remedy-selection process by narrowing
the scope of options, using site characteristics and
technology considerations.
Pilot Sites. OERR is looking for wood-treatment
sites where it can test its presumptive remedy initia-
tive.
-------
What Will This Initiative Accomplish?
EPA expects the presumptive remedy initiative to reduce
the time spent on RI/FSs and to help better integrate the
removal and remedial programs.
By being better prepared when the assessment starts—i.e.,
knowing what contaminants to expect and the best ways to
deal with them—and by using a team of experts, we can
reduce the time spent on RI/FSs considerably. Currently,
individual sites may undergo similar, sequential assess-
ments from the removal program, the site assessment
program, the remedial program, and even the Resource
Conservation and Recovery Act (RCRA) program. In
addition, the U.S. Public Health Service's Agency for Toxic
Substances and Disease Registry (ATSDR), State and local
agencies, and even private parties may conduct their own
studies. A standardized sampling and assessment process
may reduce the consecutive studies required at these sites.
We expect to do'comprehensive cleanup of hazardous
waste sites through Superfund's removal or remedial au-
thority. The team of experts contemplated by the pre-
sumptive remedy initiative will cross program lines, as
will their participation at individual sites. The presump-
tive remedies will be applicable regardless of which aspect
of Superfund is responsible for the site cleanup.
Innovative technologies will always be important to Su-
perfund, since they can reduce disposal quantities, and
save time and money. The team of experts will consider the
use of innovative technologies at specific sites. As experi-
ence is gained, we will incorporate appropriate innovative
technologies into the technology matrix. They may also be
incorporated in the computer-assisted remedy selection
program.
What ss to F@if©w?
Similar presumptive remedy initiatives for other types of
sites, such as landfills and metal-plating facilities are cur-
rently before the presumptive remedy workgroup. The
types of contaminates to be addressed include PCBs, asbes-
tos, solvents, pesticides, metals, and dioxin.
Further infonnation on the wood-treatment site initiative
is available from Harry Allen of the Environmental Re-
sponse Team at FTS 340-6740. or (201) 321-6740.
-------
United States
Environmental
Protection Agency
Office of Solid Waste
and Emergency
Response
Publication 9360.
-------
cost; however, a sequential process may be necessary at
times.
WOQJD TITTER TECTJKOL08Y
Site
B. Est*f>U& Site ScrKoJnj CrfferfcF Bassx! oa Actasl «r
Water
.';• 5. T^ATES TECilM)LOGY
B. , n* fteltartiMtt
*,;;,;$*ijN*£ifei
• . 5s. .••^j-' ** *• *• ^Ji. «
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at*
' J ' • '
PRACTICAL CONSIDERATIONS FOR
FACILITATING TECHNOLOGY SELECTION
1. If the product is still in original containers it should
be returned to the manufacturer, if possible. Reuse
of material (i.e., process liquids) and relocation of
equipment to other permitted facilities should be
considered. Phase reparation should be conducted;
water and emulsified product could be treated on
site. LNAPLs and DNAPLs may or may not be
recyclable depending on the purity of the recovered
phase.
2. Where any of the principal wood treating chemicals
(creosote, PCP, or CCA) can be recovered in high
enough concentrations to warrant reuse in any
process, recycling becomes the preferred
technology. The recognized Waste Exchanges are
listed in Appendix A. The alternative to reuse or
recycling is to treat the material as waste along with
other contaminated liquids or solids.
-------
3. If the product, (e.g., POP), is in storage tanks, then
it should be analyzed for dioxins/furans and cross
contaminants. Total pumpable and non-pumpable
sludge in tanks and drums should also be
determined.
4. Site characterization should proceed as a single,
multi-media sampling event whenever possible.
Field screening methods should be integrated into
the sampling and analysis plan in order to
accelerate information gathering. Data quality
objectives must reflect the ultimate use of the
results, but all samples taken during a single event
may not require the same level of data quality.
*. !
5. Site preparation and bulk material handling needs
require evaluation wherever soil treatment is being
considered. Pretreatment renders a material suitable
as feed for a treatment process. The technology
selection should be evaluated for consistency with
the overall remedy for the site. Site preparation and
pretreatment activities include but are not limited to
the following:
A. Site Stabilization
1. Fencing and security
2. Capture and treatment of runoff
3. Containment of leaking vessels
4. Use of liners and covers
5. Capping and containment
6. Evaluation of on-site pretreatment for off-
site disposal
B. Material Handling, Waste Segregation, and
Pretreatment
1. Surface material removal (poles, tanks,
wildings, product, etc.)
2. Excavation & stockpiling
3. Sizing
a. Screening of inert and oversized
materials
b. Particle fractionation or hydrosieving
c. Debris handling
4. Pretreatment
6. In general, other than in processing areas and
storage tanks, the highest concentrations of
contaminants may be found in surface and buried
waste lagoons. Contamination can migrate
vertically from these lagoons to significant depths.
Hydrogeologic studies may be necessary to discern
such contamination and additional technologies for
remediation may have to be considered.
7. Surface lagoons, soil areas, drip pads, and
sediments should be gridded and sampled to
determine the horizontal and vertical extent of
contamination. Soil and sludge characterization
relevant to treatment selection should reflect the
information needs detailed in Table in.
8. Excavation of contaminated soil should generally
not be done until the final treatment technology has
been selected, except where it is deemed necessary
to reduce an imminent hazard or to control
migration. Where possible, excavated organic and
inorganic contaminants, and high and low
concentration materials should be staged separately.
9. It is usually too expensive to ship quantities of
greater than 5,000 cubic yards of contaminated soil
off-site for disposal. Pretreatment of soil and water
may be required prior to shipment or discharge to
another treatment facility.
10. Circumstances may arise where capping and
containment of material with relatively low toxicity
and mobility is an appropriate remedy. Such
instances will require careful evaluation.
11. Verification of expected treatment efficiencies
should be consistent with accepted Superfund
quality assurance/quality control guidance.
12. Health and safety considerations enter into the
technology selection process as described in the
Health and Safety Plan (HASP). Air monitoring to
support the HASP may include on-site or off-site
components.
For Additional Information Contact
John Harris
Response Standards and Criteria Branch
Emergency Response Division (5202C)
U.S.EJP.A.
401 M. St S.W., Washington D.C. 20460
(703)603-8780
-------
TABLE I
Technologies for Treatment of Sludge. SoiJLanft Sediment
Soil Washing/
Immob5
80-90% TCLP
(B,P,F)
Immobilization1-2
90 - 99% (B.P.F)
Incineration
Other Thermal
Treatment1
BiotreatmentS3
Dechlorination3
Soil Washing/Bio3
90 - 99% (BJP.F)
Incineration1
Other Thermal
Treatment3
Biotreatment33
Soil Washing/Bio3
95 - 99% (BPJO
Incineration2
Other Thermal
Treatment1
BiotreatmentS3
PCP + Creosote
Soil Washing/Bio3
Incin/Immob Ash2
Soil Washing/Bio/
Creosote + CCA
Incin/Immob/Ash22
Soil Washing/Bio/
Immob3
Dechlorin/ImraobS3
1. Arsenical compounds are often problematic for stabilization; however, the levels of arsenical compounds typically found
at wood treater sites is low enough to not present concerns.
2. These technology recommendations assume that no site-specific constraints exist Technology selection should ensure
that the specified treatment efficiencies will meet established cleanup goals.
3 These other technologies may warrant site-specific evaluations, RI/FSs, focused feasibility studies (FFSs), or
engineering evaluations/cost analvses (EE/CAs) because they lack full-scale performance data. Site-specific conditions
also may favor a subset of me major technology. Bench-scale and/or pilot studies may be necessary to refine the
selection of the most appropriate specific treatment method.
4. Performance data are from the Risk Reduction Engineering Laboratory (RREL). The database is derived&om bench
scale (B), pilot scale (P), or full scale (F) demonstration projects. Dashes indicate insufficient dafck The RK£L_is
updated on a regular basis and is available through the Alternative Treatment Technology Information Center (ATTIC).
The numbers represent total treatment efficiency, not DRE. Additional technologies and their treatment efficiencies
will be added as more information becomes available.
5 Performance efficiency for treatment trains is a function of contaminant concentration, matrix and volume. It can
generally be presumed that the performance of treatment trains will equal or exceed that of the individual treatment
technologies.
-------
TABLE H
Technologies for Treatment of Surface Water and Ground Water
CCA
POP
Creosote
Creosote + PCP
Creosote + CCA
PCP + CCA
fSftstiftaft^* "***
Precipitation
Reverse Osmosis
Ion Exchange
Caibon Treatment
Biotreatment
Oxidation
Caibon Treatment
Biotreatment
Oxidation
Caibon Treatment
Biotreatment
Oxidation
Caibon Treatment
Oxidation
Precipitation
Carbon Treatment
Oxidation
Precipitation
97 - 99% (B,P,F)
99% (P)
95-99%(P)
99% OW)
99%(B,P)
82 - 99% (PJF)
99% (P.F)
99%(BJ>)
82 - 99% (P J)
99%J or Ultraviolet Oxidation
Treat Metals = Reverse Osmosis or Ion Exchange or Chemical Precipitation and Immobilization of
Residues
* Performance data from the RREL (Risk Reduction Engineering Laboratory). Database is derived from
bench scale (B), pilot scale (P), or full scale (F) demonstration projects. Dashes in the table indicate
insufficient data.
-------
TABLE IE
Information Needs and Process Limitations
Thennal Treatment •
Incineration
i) BTU value
ii) Volatile metals cones.
iii) Alkali metals (Na,K) cones.
iv) Elemental analysis (N,S,P,Cl,etc.)
v) Moisture content
vi) Pumping chars, and viscosity
i) High moisture content
ii) High alkali metals soil
iii) Elevated levels of mercury,
organic phosphorus
iv) Volume <3000-3000 cu. yds.
Thermal Treatment •
Desorption
i) Melting and boiling points
ii) Volatile metals cones.
iii) Flash points
iv) Elemental analysis (N,S,P,Cl,ete.)
v) Vapor pressures
vi) Optimum desorption and
destruction temperatures
vii) Moisture content
i) Elevated levels of halogenated
ii) Presence of mercury
iii) Corrosivity
Immobilization
i) TOC (oils, TPH, humic material.
etc.)
ii) Grain size distribution
iii) Soluble salts
iv) Cation Exchange Capacity (CEQ
i) TPH
ii) Humic matter <20%
Biotrcatment -
In-situ
i) Indigenous microorganisms
ii) Degradation rates
iii) Solubility
iv) Nutrient requirements and existing
conditions of pH, temp., oxygen,
moisture, etc.
v) Depth to ground water and
thickness of contaminated zone
vi) Permeability of the soil
i) Tc .ic metals, chlorinated
organics, pH outside 4.5-9,
limiting growth factors
ii) Ambient temp, below 15°C
iii) Short time/growth season
iv) RaMall/evapotranspiration
rate/percolation rate ratios too high
or too low
v) Limiting initial and final cones.
Biotrcatment -
Ex-situ
i) Indigenous microorganisms
ii) Degradation rates
iii) Solubility
iv) Nutrient requirements and existing
conditions of pH, temp., oxygen,
moisture, etc.
i) Lack of indigenous microbes
ii) Toxic metals, highly
chlorinated organics, pH
outside 4.5-9, limiting growth
factors
iii) See also "In-situ", above
Base-Catalyzed
Dcchlorination
i) Heavy metals cone.
ii) Reactivity at high pH
iii) Elemental analysis (N,P,S,C1, etc.)
iv) Redox potential
v) TOC, humic material and clay content
i) Heavy metals and excess soil moisture
(>20%) may require special treatment
ii) High organic and clay content may
extend reaction time
Soil Washing
i) Solubilities and partition coefficients
ii) Grain size distribution
iii) TOC and humic material content
iv) Cation Exchange Capacity (CEC)
i) High hydraphobic TOC and humic
material content inhibits detergency
ii) >30% silt and clay panicles cancels
out volume reduction benefit of process
iii) Surfactant solutions may cause
operating problems
.
-------
REFERENCES
Contaminants and
I Options
USEPA. ORD, RREL. September 1992
^ Preservine ShM FPA/cw<;/7 orwhi i ,TO™
Research Infonnation. Cincinnati, OH 45268, November 1990 fcPA/625/7-90/D1 '• USEpA Office of Environmental
Superfund LDR
93473WS. USEPA, OSWER, September 1990
J
Guidance, EPA/540/2-91/013A, USEPA, OREUuiy' 1991
^^ • j . f~
Engineering and Technology Devetormenr^archT^gsT'1 ^"^ EPA/540/2-89A>S2, USEPA Office of Environmental
Superfund Publication
Screening - Interim
.
Document in Preparation by USEPA, OERR, June 1992
USEPA, OERR Publication 9360.4-10, November,
4; Hasanlous Waste - Interim Fin^ii OSWER Directive
novativ
TIO, October 1991
dew and Guide to Infnrmarir
EPA/540/9-91/D02, USEPA OSWER,
-------
APPENDIX A - U.S. Waste Exchanges
CALIFORNIA WASTE EXCHANGE
Robert McConnick
Department of Health Services
Toxic Substances Control Division
400 P Street
Sacramento, CA 95812
(916) 324-1807
INDIANA WASTE EXCHANGE
Environmental Quality Control
1220 Waterway Boulevard
P.O. Box 1220
Indianapolis, IN 46206
(317) 232-8188
INDUSTRIAL MATERIAL EXCHANGE
SERVICE
Diane Shockey
2200 Churchill Road, #31
Springfield, IL 62794-9276
(217) 782-0450
FAX: (217) 782-9142
INDUSTRIAL MATERIALS EXCHANGE
Bill Lawrence
172 20th Avenue
Seattle, WA 98122
(206) 296-4899
FAX: (206) 296-0188
PACIFIC MATERIALS EXCHANGE
Bob Smee
1522 No. Washington St.
Suite 202
Spokane, WA 99205
(509) 325-0551
FAX: (509) 325-2086
NATIONAL WASTE EXCHANGE NETWORK
1-800-858-6625
RENEW
Hope Castillo
Texas Water Commission
P.O. Box 13087
Austin, TX 78711
(512) 463-7773
FAX: (512) 463-8317
INDUSTRIAL WASTE INFORMATION
EXCHANGE
William E. Payne
New Jersey Chamber of Commerce
5 Commerce Street
Newark, NJ 07102
(201) 623-7070
MONTANA INDUSTRIAL WASTE
EXCHANGE
Don Ingles
Montana Chamber of Commerce
P.O. Box 1730
Helena, MT 59624
(406) 442-2405
NORTHEAST INDUSTRIAL WASTE
EXCHANGE
Lewis M. Cutler
90 Presidential Plaza
Suite 122
Syracuse, NY 13202
(315) 422-6572
FAX: (315) 422-9051
SOUTHEAST WASTE EXCHANGE
Maxi May
Urban Institute
DepL of Civil Engineering
Univ. of North Carolina
Charlotte, NC 28223
(704) 547-2307
SOUTHERN WASTE INFORMATION
EXCHANGE
Gene Jones
P.O. Box 960
Tallahassee, FL 32313 '
(904) 644-5516
FAX: (904) 574-6704
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I
5SB
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
JUL 24 1997
OFFICE OF
SOLID WASTE AND EMERGENCY
RESPONSE
MEMORANDUM
SUBJECT:
FROM:
TO:
Feasibility Study Analysis and Administrative Record for Woodtreater
Presumptive Remedy
PURPOSE
fhorfia/sTfeckens, Center Director
Region 3/8 Accelerated Response Center
Office of Emergency and Remedial Response
Director, Office of Site Remediation and Restoration
Region I
Director, Emergency and Remedial Response Division
.Region II >,
Director. Hazardous Waste Management Division
Regions III, IX
Director, Waste Management Division
Region IV
Director, Superfund Division
Regions V, VI, VII . .
Assistant Regional Administrator, Office of Ecosystem Protection & Remediation
Region VIII
Director, Environmental Cleanup Office
Region X
The purpose of this memorandum is to transmit for Regional use the Administrative
Record documents supporting the policy directive entitled "Presumptive Remedies for Soils,
Sediments, and Sludges at Wo6d Treater Sites." This directive was forwarded to the Regions in
December,' 1995, and the enclosed materials should be placed with this directive in the Regional
Administrative Record center to justify the presumptive remedy approach at Woodtreater sites.
The actual administrative record is fairly large and is being forwarded to the list of individuals
provided in Attachment A. The list of the presumptive remedy workgroup members is^
included in Attachment B. The contents along with a general guide on the presumptive
remedies Administrative Record is provided to you in Attachment C.
Recycled/Recyclable • Printed with Vegetable Oil Based Inks on 100% Recycled Paper (40% Postconsumer)
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BACKGROUND
Presumptive remedies are preferred technologies for a common category of sites, based
on historical patterns of remedy selection and EPA's scientific and engineering evaluation of
performance data on technology implementation. The use of presumptive remedies will improve
the effiency of the Superfund program by building on past experience. The directive, along with
the supporting documentation, will provide practical tools to the Regions for streamlining and
accelerating remedy selection in accordance with the Superfund Accelerated Cleanup Model
(SACM).
Through this effort, seven site categories have been identified for presumptive remedy
guidance development. The supporting documentation to the Soils, Sediments, and Sludges at
Woodtreating Sites is presently being forwarded to the Regions. Others include directives
addressing volatile organic compounds (VOCs), municipal landfills, and groundwater response
strategy which have already been issued and additional directives on polychlorinated biphenyls
(PCBs), manufactured gas plants (MGPs), and grain storage.
IMPLEMENTATION
The attached documents along with the above cited presumptive remedy directives, are
key elements of the administrative record for Soils, Sediments, and Sludges at Woodtreating
Sites where the "presumptive remedy" approach is being used. Under the presumptive remedy
approach, the Feasibility Study (FS) or Engineering Evaluation/Cost Analysis (EE/CA) is limited
to considering only those technologies identified by EPA as presumptively appropriate for the
specific site.
The attached documents in essence serve as a generic FS establishing the preferred
technologies and screening out all other technologies. The documents should be placed in the
administrative record, along with the appropriate directive, at the time the decision is made to use
the presumptive remedy approach. ~
Regional personnel involved with woodtreater presumptive remedies sites should
familiarize themselves with all the contents of the directive and the administrative record for this
site type. A brief summary of how to use the administrative record along with the associated
directive is presented in Attachment C. The guide is available electronically on the Superfund
homepage under the 'Technical Resources" section. The internet address is:
www.epa.gov/superfund/oerr/techres/index.htm. For further information, please contact
Frank Avvisato of my staff at 703-603-8949.
Attachments
cc: Stephen Luftig
George Wyeth
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ATTACHMENT A
PRESUMPTIVE REMEDIES ADMINISTRATIVE RECORDS CONTACTS
REGION CONTACT PHONE
617-573-9647
212-637-4296
215-566-3157
404-347-5059
312-353-5821
214-665-6537
913-551-7515
303^312-6551
415-744-2370
206-553-1751
I
II
III
IV
v
VI
VII
VIII
IX
X
Margaret Meehan
Jennie Delcimento
Anna M. Butch
Debbie Jourdan
Janet Pfundheller
Nancy G. Yarberry
Barry Thierer
Carole Macy
Craig Cooper
Bob Phillips
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ATTACHMENT B
Presumptive Remedies Workgroup Members
George Wyeth, OGC
Frank Avvisato, OERR
Scott Fredericks, OERR
Bruce Means, OERR
Harry Allen, ERT
Frank Freestone, ORD
Fran Kremer, ORD
Jim Cummings, TIO
Mike Nalipinski, Region I
Mel Hauptman, Region II
Paul Leonard, Region III
Felicia Barnett, Region IV
Dion Novak, Region V
Cathy Gilmore, Region VI
Diana Engeman, Region VII
Victor Kettelapper, Region VIII
Craig Cooper, Region IX
Eric Winiecki, Region X
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ATTACHMENT C
PRESUMPTIVE REMEDY ADMINISTRATIVE RECORD CONTENTS AND GUIDE
PURPOSE
This guide is intended to assist the U.S. Environmental Protection Agency (EPA)
Regional staff and the public in understanding the administrative record documents and site-type
directives for supporting presumptive remedies at individual sites. These documents and
directives in essence serve as a generic FS establishing the preferred technologies as
presumptive, and screening out all other technologies. Using this information will potentially
streamline and accelerate the remedy selection process. In general, the administrative record for
a site vising presumptive remedies will consist of site-specific information (e.g., technical,
administrative, legal) and the presumptive remedies administrative record components
highlighted in the section below.
Note: As mentioned earlier, the guide is available electronically on the Superfund homepage
under the "Technical Resources" section. The internet address is:
vmw.epa.gov/superfund/oerr/techres/index.htm.
CONTENTS OF ADMINISTRATIVE RECORD
This section highlights and provides a brief discussion of the primary components of the
administrative record for a site where the presumptive remedy approach is being used. The
contents of the Record include:
I. Presumptive Remedies Directives
II. Feasibility Study Analysis Report (FSAR) and Supporting Technical Background
Documents
III. Feasibility Studies for sites supporting FSAR
IV. Records of Decision for sites supporting FSAR
V. Other Reference Documents
A general discussion on the Presumptive Remedies Directives and the FSAR is provided below.
I. Directives:
The appropriate site-type directives (e.g., Presumptive Remedy for CERCLA Municipal
Landfill sites) together with the General Policy and Procedure directive must be included in the
Administrative Record. The policy and procedures directive addresses overall policy and
programmatic issues associated with presumptive remedies. The site-type directive's text and
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associated tables provide information on the technologies that were selected as presumptive
remedies and provides the justification for such a selection. Appendix A to the site-type
directive provides a statistical summary (drawn from the Feasibility Study Analysis for the site
category) of the technologies screened out from further consideration. Appendix B contains a
"nine criteria" analysis of the recommended technology or technologies. (NOTE: only seven
criteria are addressed, because state and local acceptance can only be evaluated site specifically.)
Appendix C contains the site-specific data collection forms which presents the site specific
information from the FSs and RODS concerning remedy selection.
II. FS Analysis Reports
Another key component of the Administrative Record is the FS Analysis Report for the
particular category of site. The FS Analysis Report provides information on the technologies
that were screened from further consideration in site universe of FSs analyzed. This report in
essence provides the justification for not considering these technologies in site-specific FSs when
the presumptive remedy approach is being implemented. The report describes each technology,
and the strengths and weaknesses of each, including factors that tend to limit each technology's
usefulness. For each technology considered, the FS Analysis contains a conclusion explaining
why that technology is not generally suitable for such sites. Finally, each document contains
tables analyzing the technologies in terms of the remedy selection criteria.
The conclusions in the FS Analyses often contain some caveats because the suitability of
a given technology may vary depending on site specific conditions. While the technology may
be generally unsuitable for the particular type of site, it may be suitable for further consideration
in exceptional cases.
The information in the FS Analyses is drawn in part from prior feasibility studies, and
partly from other sources (e.g., technical resource documents). In some cases, either to respond
to comments or for other reasons, users may wish to review the underlying documentation used
in developing the FS analysis.
•(
Finally, the appendices the FS Analysis contain useful supporting information. Appendix
A to the FS Analyses provides a statistical summary of the rationale or basis used for screening
out the non-recommended technologies as cited in past feasibility studies (similar to Appendix A
in directive). Appendix B describes in greater detail the reasons given in past feasibility studies
for screening each technology out where it was excluded at the preliminary screening phase.
Appendix C summarizes the findings of each feasibility study analyzed as part of this study, on a
site by site basis.
III. Technical Background Documents, Feasibility Studies, Records of Decision, and
Other Reference Materials
The directives and the FS Analyses discussed above are documents that were based on
various technical literature, site-specific FS Reports and Records of Decisions and other
reference materials. As such, this material is also an integral part of the administrative record
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and should be placed with the other materials to support presumptive remedies at a particular
site.
IMPLEMENTATION
The user should be aware that both the directives and FS analyses present statistical
information on the conclusions drawn in past feasibility studies including the number of times
each technology was rejected at the preliminary screening phase, the number of times each was
rejected at the detailed analysis phase, and the number of times each was selected. While such
statistical analysis does not provide reasons for such decisions (and the reasons may have
differed from site to site), it can be valuable as a reflection of the agency's past|experience.
Before choosing the presumptive remedy approach, Agency personnel should review the
FS Analysis to determine whether unusual site conditions exist that warrant further consideration
of non-presumptive remedy technologies. Additionally, the use of this approach should be
discussed early and often with the community, state, and the potentially responsible parties
(PRPs). Further assistance on the implementation of this initiative is available through the
Headquarters and Regional Presumptive Remedies contacts (highlighted in Appendix C).
Additionally, the user should note that these documents are meant to provide a basic level
of justification for the presumptive remedy, not to answer all possible questions or comments
about the selection of the presumptive remedy. In some cases, outside parties may submit
comments supporting technologies other than those recommended. A decision will have to be
made in each such case as to whether the material provided here adequately addresses the
comment, or whether additional record support is needed.
For example, if a commenter contends that unusual site conditions warrant considering a
different technology, the FS analysis should be reviewed to determine whether it adequately
addresses that argument. If a comment supports a technology not discussed in the FS analysis at
all (e.g., an innovative technology), a site specific response will have to be provided. In such
cases a decision might be made to consider the innovative technology along with the
recommended technologies. A case-by-case decision will have to be made based on the
information available on the technology and best engineering judgement.
Finally, if all parties have agreed to this approach, the administrative and technical
documents (e.g., Work Plan, FSs, EE/CAs, Proposed Plans, RODs, etc.) for the site should
indicate that the site followed the presumptive remedy approach and is supported by the
documentation provided in the administrative record.
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United Slates
Environmental Protection
Agency
5ond Waste and
Emergency Response
EPA 540-R-96-023
OSWER 9283.1-12
PBS6-963508
October 1996
Superfund
&EPA
Presumptive Response Strategy
and Ex-Situ Treatment
Technologies for Contaminated
Ground Water at CERCLA Sites
Final Guidance
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NOTICE
This document provides guidance to EPA staff. It also provides guidance to the public and to the
regulated community on how EPA intends to exercise its discretion in implementing the National
Contingency Plan. The guidance is designed to implement national policy on these issues. The
document does not, however, substitute for EPA's statutes or regulations, nor is it a regulation
itself. Thus, it cannot impose legally-binding requirements on EPA, States, or the regulated
community, and may not apply to a particular situation based upon the circumstances. EPA may
change this guidance in the future, as appropriate.
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CONTENTS
Section
FIGURES • "»
HIGHLIGHTS - &
ACRONYMS USED IN THIS GUIDANCE »v
PREFACE • • • v
1.0 INTRODUCTION • 1
I.I Purpose of Guidance 1
1.2 Expectations and Objectives for Ground-Water Cleanup 2
1.2.1 Program Expectations • 2
1.2.2 Objectives for Site Response Actions • • • 2
1.3 Lessons Learned 3
1.3.1 Sources and Types of Contaminants • 3
1.3.2 Factors Limiting Restoration Potential 3
1.3.3 Assessing Restoration Potential • • 5
2.0 PRESUMPTIVE RESPONSE STRATEGY 5
2.1 Definition and Basis for Strategy 5
2.1.1 Benefits of Phased Approach • 6
2.1.2 Early Actions ... ^... 6
2.1.3 Monitoring • - 8
2.2 Phased Response Actions 8
2.2.1 Two Separate Actions • 8
2.2.2 Phasing of a Single Action • 8
2.3 Post-Construction Refinements • • 11
2.3.1 Types of Refinements • 1 *
2.3.2 Documenting Refinements • 11
2.4 Integrating Response Actions • 12
2.4.1 Integrating Source Control and Ground-Water Actions 12
2.4.2 Combining Ground-Water Restoration Methods 12
2.5 Strategy for DNAPL Sites 13
2.5.1 Site Characterization 14
2.5.2 Early Actions 14
2.5.3 Long-Term Remedy •• • • • 14
2.6 Areas of Flexibility in Cleanup Approach 15
2.6.1 Beneficial Uses and ARARs • • • • 15
2.6.2 Remediation Timeframe i6
2.6.3 Technical Impracticability 1?
2.6.4 Point of Compliance 17
2.6.5 Natural Attenuation 18
2.6.6 Alternate Concentration Limits 18
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3.0 PRESUMPTIVE TECHNOLOGIES 19
3.1 Presumptive Technologies for Ex-Situ Treatment • • 19
3.1.1 Design Styles within Presumptive Technologies 20
3.1.2 Benefits of Presumptive Technologies 20
3.1.3 Consideration of Innovative Technologies 2°
3.2 Basis for Presumptive Technologies 21
3.2.1 Sources of Information 21
3.2.2 Rationale for Indentifying Presumptive Technologies 21
3.3 Remedy Selection Using Presumptive Technologies 22
3.3.1 Use of Technologies in Treatment Systems 22
3.3.2 This Guidance Constitutes the FS Screening Step • • • •, 23
3.3.3 Deferral of Final Technology Selection to RD 23
3.4 Information Needed for Selecting Technologies 24
3.4.1 When Should this Information be Collected? 24
3.4.2 Extraction Flow Rate 25
3.4.3 Discharge Options and ARARs 26
3.4.4 Water Quality of Treatment Influent 26
3.4.5 Treatability Studies 26
3.5 Treatment Technologies for Aquifer Tests 27
3.5.1 Treatment Needs during Aquifer Tests 27
3.5.2 Treatment Technologies for Aquifer Tests • 27
4.0. REFERENCES 28
APPENDICES
A. Additional Background Information •
Al Background on DNAPL Contamination - • • • • • ••-• • • A~2
A2 Contaminants Most Frequently Reported in Ground Water at CERCLA NPL Sites A-4
A3 Examples of In-Situ Treatment Technologies A-6
A4 Definition and Discussion of Pulsed Pumping A-8
B. ROD Language Examples For Selected Remedy
Bl Phased Implementation of Ground-Water Remedy o-l
B2 Phased Implementation of Extraction Component of Remedy at a DNAPL Site B-3
B3 Deferring Selection of Treatment Components to Remedial Design B-5
B4 Suggested ROD Language from 1990 OSWER Directive B-7
C. Ex-Situ Treatment Technologies for Ground Water
Cl Ex-Situ Technologies Considered in Sample of 25 Sites t--'
C2 Other Components Needed for Treatment Trains • C-3
C3 Information Needed for Selection of Technologies and Design of Treatment Train C-4
C4 Advantages and Limitations of Presumptive Treatment Technologies C-9
D. Descriptions of Presumptive Treatment Technologies
Dl AirStripping £'j
D2 Granular Activated Carbon i:%
D3 Chemical/UV Oxidation • p_7
D4 Aerobic Biological Reactors r>p
D5 Chemical Precipitation p-I I
D6 Ion Exchange/Adsorption 0-13
D7 Electrochemical Methods ;'
D8 Aeration of Background Metals
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FIGURES
Figure Page
1 Examples of Factors Affecting Ground-Water Restoration Potential 4
2 Phased Ground-Water Actions: Early Action Followed by Long-term Remedy 9
3 Phased Ground-Water Actions: Long-Term Remedy Implemented in Phases 10
Al-1 Components of DNAPL Sites A-2
Al -2 Types of Contamination and Contaminant Zones of DNAPL Sites (Cross-Section) A-2
HIGHLIGHTS
Highlight Pace
1 Presumptive Response Strategy 6
2 Early Actions that Should be Considered 7
3 Remedy Refinements for Extraction/Treatment Remedies 12
*
4 Presumptive Technologies for'Treatment of Extracted Ground Water 20
5 Summary of Site Information Needed for Treatment Train Design 25
Hi
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ACRONYMS USED IN THIS GUIDANCE
ACL Alternate Concentration Limit NPL
ARAR Applicable or Relevant and OERR
Appropriate Requirement
CERCLA Comprehensive Environmental ORD
Response, Compensation, and
Liability Act of 1980, as amended by OS WER
SARA
CERI Center for Environmental Research PCB
Information
CFR Code of Federal Regulations POTW
CSGWPP Comprehensive State Ground Water RARA
Protection Program
DNAPL Dense Nonaqueous Phase Liquids RD
EPA Environmental Protection Agency RD/RA
ESD Explanation of Significant * RI
Differences
RI/FS
FS • Feasibility Study
GAC Granular Activated Carbon ROD
LNAPL Light Nonaqueous Phase Liquids SACM
MCL Maximum Contaminant Level
SARA
MCLG Maximum Contaminant Level Goal
NAPL Nonaqueous Phase Liquid UV
NCP National Oil and Hazardous VOC
Substances Pollution Contingency
Plan
National Priorities List
Office of Emergency and Remedial
Response
Office of Research and Development
Office of Solid Waste and Emergency
Response
Polychlorinated Biphenyl
Compounds
Publicly Owned Treatment Works
Resource Conservation and Recovery
Act
Remedial Design
Remedial Design/Remedial Action
Remedial Investigation
Remedial Investigation/Feasibility
Study
Record of Decision
Superfund Accelerated Cleanup
Model
Superfund Amendments and
Reauthorization Act of 1986
Ultra Violet (light)
Volatile Organic Compound
IV
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PREFACE
Presumptive Remedies Initiative. The objective of the presumptive remedies initiative is to use the
Superfund program's past experience to streamline site investigations and speed up selection of cleanup
actions. Presumptive remedies are expected to increase consistency in remedy selection and implementation,
and reduce the cost and time required to clean up similar types of sites. The presumptive remedies approach
is one tool within the Superfund Accelerated Cleanup Model (SACM) (EPA, 1992d).
Presumptive remedies are preferred technologies for common categories of sites, based on historical
patterns of remedy selection and EPA's scientific and engineering evaluation of performance data on
technology implementation. Refer to EPA Directive, Presumptive Remedies: Policy and Procedures (EPA,
1993d) for general information on the presumptive remedy process and issues common to all presumptive
remedies. This directive should be reviewed before utilizing a presumptive remedy and for further
information on EPA expectations concerning the use of presumptive remedies. "Presumptive remedies
are expected to be used at all appropriate sites," except under unusual site-specific circumstances (EPA,
1993d).
Other Presumptive Remedy Guidance. Previous fact sheets from EPA's Office of Solid Waste and
Emergency Response (OSWER) have established presumptive remedies for municipal landfill sites (EPA.
19930, for sites with volatile organic compounds in soils (EPA, 1993e) and for wood treater sites (EPA,
1995g). A presumptive response selection strategy for manufactured gas plant sites is under development.
Additional fact sheets are in progress for sites contaminated with polychlorinated biphenyl compounds
(PCBs), metals in soils and for grain storage sites.
Relation of this Guidance to Other Presumptive Remedies. T^e fact sheets mentioned above provide
presumptive remedies (or a strategy for selecting remedies) for "source control" at specific types of sites.
With respect to ground-water response, source control refers to containment or treatment of materials that
may leach contaminants to ground water, or a combination of these approaches. In general, treatment is
expected for materials comprising the principal threats posed by a site, while containment is preferred for low
level threats (EPA. 1991c). Where contaminants have reached ground water and pose an unacceptable risk to
human health or the environment, a ground-water remedy will generally be required in addition to the source
control remedy and this guidance should be consulted.
Instead of establishing one or more presumptive remedies, this guidance defines a presumptive response
strategy. EPA expects that some elements of this strategy will be appropriate for all sites with contaminated
ground water and all elements of the strategy will be appropriate for many of these sites. In addition, this
guidance identifies presumptive technologies for the ex-situ treatment component of a ground-water
remedy, that are expected to be used for sites where extraction and treatment is part of the remedy. (The term
presumptive technology is used in this guidance to denote only the ex-situ treatment component of a ground-
water remedy.) Other remedy components could include methods for extracting ground water, enhancing
contaminant recovery or degradation of contaminants in the subsurface, discharging treated water, preventing
contaminant migration, and institutional or engineering controls to prevent exposure to contaminants.
Applicability to RCRA Corrective Action Program. EPA continues to seek consistency between cleanup
programs, especially in the process of selecting response actions for sites regulated under the Comprehensive
Environmental Response. Compensation and Liability Act (CERCLA or Superfund program) and corrective
measures tor facilities regulated under the Resource Conservation and Recovery Act (RCRA). In general.
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even though the Agency's presumptive remedy guidances were developed for CERCLA sites, they should
also be used at RCRA Corrective Action sites to focus RCRA Facility Investigations, simplify evaluation of
remedial alternatives in the Corrective Measures Study, and influence remedy selection in the Statement of
Basis. For more information refer to the RCRA Corrective Action Plan (EPA, 1994c), the proposed Subpart
S regulations (Federal Register, 1990b). and the May 1, 1996 RCRA Corrective Action Advance Notice of
Proposed Rulemaking (Federal Register, 1996).
Use of this Guidance. The presumptive response strategy, described in Section 2.1, integrates site
characterization, early actions, remedy selection, performance monitoring, remedial design and remedy
implementation activities into a comprehensive, overall response strategy for sites with contaminated ground
water. By integrating these response activities, the presumptive strategy illustrates how the Superfund
Accelerated Cleanup Model (SACM) can be applied to ground-water cleanup. Although this response
strategy will not necessarily streamline the remedial investigation/feasibility study (RI/FS) phase, EPA
expects that use of the presumptive strategy will result in significant time and cost savings for the overall
response to contaminated ground water. By providing a mechanism for selecting achievable remediation
objectives, the presumptive strategy will minimize the need for changing these objectives during remedy
implementation. By optimizing the remedy for actual site conditions during implementation, the effectiveness
of the selected remedy can be greatly increased, which will reduce the time and cost required to achieve
remediation objectives.
The presumptive technologies for treating extracted ground water, identified in Section 3.1, are the
technologies that should generally be retained for further consideration in the Detailed Analysis portion of the
feasibility study (or in the remedial design as explained in Section 3.3.3). This guidance and its associated
Administrative Record will generally constitute the Development and Screening of Alternatives portion of the
feasibility study (FS) for the ex-situ treatment component "of a ground-water remedy (see Section 3.3.2). In
this respect, the presumptive technologies will streamline the FS for this component of a ground-water
remedy in the same way that other "presumptive remedies" streamline the FS for the overall remedy for their
respective site types (see EPA, 1993d).
VI
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1.0 INTRODUCTION
In implementing the Superfund and other
remediation programs, cleanup of contaminated
ground water has proven to be more difficult than
anticipated. For many sites, the program
expectation of returning ground waters to their
beneficial uses (see Section 1.2.1) often requires
very long time periods and may not be practicable
for all or portions of the site. Thus, the ultimate
. cleanup goal for ground water may need to be
different over different areas of the site (see
Section 1.3.1). For sites where achieving the
ultimate goal will require a long time period,
interim remediation objectives will generally be
appropriate, such as preventing further plume
migration. Therefore, a critical first step in the
remedy selection process is to determine the
full range of remedial objectives that are
appropriate for a particular site.
This guidance is intended to emphasize the
importance of using site-specific remedial
objectives as the focus of the remedy selection
process for contaminated ground water. Those
remedy components that influence attainment of
remedial objectives should receive the greatest
attention. For example if restoring the aquifer to
beneficial use is the ultimate objective, remedy
components that influence attainment of cleanup
levels in the aquifer include: methods for
extracting ground water, enhancing contaminant
recovery, controlling subsurface contaminant
sources (e.g., nonaqueous phase liquids or
NAPLs, discussed in Appendix'Al) or in-situ
treatment of contaminants. Some or all of these
remedy components should be included in
remedial alternatives that are developed and
evaluated in detail in the feasibility study (FS)
when aquifer restoration is a remedial
objective.
Although the technologies employed for treating
extracted ground water and the types of discharge
for the treated effluent are important aspects of a
remedy, they have little influence on reducing
contaminant levels or minimizing contaminant
migration in the aquifer. In developing this
guidance, historical patterns of remedy selection
and available technical information were reviewed
in order to identify presumptive technologies for
ex-situ treatment of ground water. By providing
presumptive technologies, this guidance
attempts to streamline selection of these
technologies and shift the time and resources
employed in remedy selection to other, more
fundamental aspects of the ground-water
remedy.
Although extraction and treatment has been and
will continue to be used as part of the remedy for
many sites with contaminated ground water, it
may not be the most appropriate remediation
method for all sites or for all portions of a given
contaminant plume. Also, remedial alternatives
that combine extraction and treatment with other
methods, such as natural attenuation (defined in
Section 2.6.5) or in-situ treatment, may have
several advantages over alternatives that utilize
extraction and treatment alone (see Section 2.4.2).
(Remedial alternatives are evaluated against
remedy selection criteria defined in the National
Contingency Plan at §300.430(e)(9)(iii) (Federal
Register, 1990a).) In general, the remedy
selection process should consider whether
extraction and treatment can achieve remedial
objectives appropriate for the site and how this
approach can be most effectively utilized to
achieve these objectives. This guidance also
describes a presumptive response strategy
which facilitates selection of both short and
long-term remediation objectives during
remedy selection, and allows the effectiveness
of the remedy to be improved during
implementation.
1.1 Purpose of Guidance
In summary, this guidance is intended to:
• Describe a presumptive response
strategy, at least some elements of which
are expected to be appropriate for all sites
with contaminated ground water;
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• Identify presumptive technologies for
treatment of extracted ground water (ex-
situ treatment) that are expected to be
used (see EPA. 1993d) for sites where
extraction and treatment is part of the
remedy;
• Simplify* the selection of technologies for
the ex-situ treatment component of a
ground-water remedy, and improve the
technical basis for these selections; and
• Shift the time and resources employed
in remedy selection from ex-situ
treatment to other, more fundamental
aspects of the ground-water remedy, as
discussed above.
1.2 Expectations and Objectives for Ground-
Water Cleanup
Careful consideration should be given to national
program expectations as well as site-specific
conditions when determining cleanup objectives
that are appropriate for a given site.
1.2.1 Program Expectations. Expectations for
contaminated ground water are stated in the
National Oil and Hazardous Substances Pollution
Contingency Plan (NCP). as follows:
"EPA expects to return usable ground
waters to their beneficial uses wherever
practicable, within a timeframe that is
reasonable given the particular
circumstances of the site. When
restoration of ground water to beneficial
uses is not practicable, EPA expects to
prevent further migration of the plume,
prevent exposure to the contaminated
ground water, and evaluate further risk
reduction." (Federal Register, 1990a;
§300.430 (a)(l)(iii)(F), emphasis added.)
The Preamble to the NCP explains that the
program expectations are not "binding
requirements." "Rather, the expectations are
intended to share collected experience to guide
those developing cleanup options" (Federal
Register, 1990a; at 8702).
1.2.2 Objectives for Site Response Actions.
The program expectations can be used to define
the following overall objectives for site response
actions, which are generally applicable for all sites
with contaminated ground water:
® Prevent exposure to contaminated ground
water, above acceptable risk levels;
• Prevent or minimize further migration of
the contaminant plume (plume
containment);
* Prevent or minimize further migration of
contaminants from source materials to
ground water (source control); and
« Return ground waters to their expected
beneficial uses wherever practicable
(aquifer restoration).
In this guidance the term "response action" is used
to indicate an action initiated under either
CERCLA removal or remedial authority.
"Response objective" is the general description of
what a response action is intended to accomplish.
Source control is included as an objective because
the NCP expectation of aquifer restoration will
not be possible unless further leaching of
contaminants to ground water is controlled, from
both surface and subsurface sources. The
objectives, given above, are listed in the
sequence in which they should generally be
addressed at sites.
Monitoring of ground-water contamination is not
a separate response objective, but is necessary to
verify that one or more of the above objectives has
been attained, or will likely be attained (see
Section 2.1.3). Other response objectives may
also be appropriate for some sites, depending on
the type of action being considered and site
conditions (e.g., maximizing the reuse of extracted
ground water may be an appropriate objective for
some sites). Response objectives may be
-------
different over different portions of the
contaminant plume, as discussed in Section
1.3.1.
1.3 Lessons Learned
The most important lesson learned during
implementation of Superfund and other
remediation programs is that complex site
conditions are more common than previously
"anticipated, including those related to the source
and type of contaminants as well as site
hydrogeology. As a result of these site
complexities, restoring all or portions,of the
contaminant plume to drinking water or similar
standards may not be possible at many sites using
currently available technologies.
1.3.1 Sources and Types of Contaminants.
Approximately 85 percent of sites on the
CERCLA National Priorities List (NPL sites)
have some degree of ground-water contamination.
Contaminants have been released to ground water
at a wide variety of site types and can include a
variety of contaminants and contaminant
mixtures. Sources of contaminants to ground
water not only include facilities from which the
original release occurred (e.g.. landfills, disposal
wells or lagoons, storage tanks and others) but
also include contaminated soils or other
subsurface zones where contaminants have come
to be located and can continue to leach into ground
water (e.g., NAPLs, see Appendix Al). Thus, the
plume of contaminated ground water may
encompass NAPLs in the subsurface (sources of
contamination) as well as dissolved contaminants.
In this case, different response objectives may be
appropriate for different portions of the plume.
For example, source control (e.g.. containment)
may be the most appropriate response objective
for portions of the plume where NAPLs are
present and can not practicably be removed, while
aquifer restoration may be appropriate only for the
remaining portions of the plume (see Section
2.5.3).
Although originating from a variety of sources,
contaminants which reach ground water tend to be
those that are relatively mobile and chemically
stable in the subsurface environment (e.g., less
likely to sorb to soil particles or degrade above the
water table). Organic and inorganic contaminants
most frequently found in ground water at
CERCLA sites are listed in Appendix A2.
Sixteen of the 20 most common organic
contaminants are volatile organic compounds
(VOCs). Of the 16 VOCs, 12 are chlorinated
solvents and four are chemicals found in
petroleum fuels. Petroleum fuels are light
nonaqueous phase liquids (LNAPLs, with a
density lighter than water); while most chlorinated
solvents are dense nonaqueous phase liquids
(DNAPLs) in pure form (see Appendix A1).
1.3.2 Factors Limiting Restoration Potential.
At many sites, restoration of ground water to
cleanup levels defined by applicable or relevant
and appropriate requirements (ARARs) or risk-
based levels may not be possible over all or
portions of the plume using currently available
technologies. Two types of site conditions inhibit
the ability to restore ground water:
® Hydrogeologic factors, and
• Contaminant-related factors.
Recent studies by EPA and others have concluded
that complex site conditions related to these
factors are more common at hazardous waste sites
than originally expected (EPA, 1989a, 1992b,
1992g. and 1993b; and the National Research
Council. 1994). Examples of hydrogeologic or
contaminant-related factors affecting the difficulty
of restoring ground water are given in Figure 1.
These types of site conditions should be
considered in the site conceptual model, which is
an interpretive summary of the site information
obtained to date (not a computer model). Refer to
EPA, I993b and 1988a for additional information
concerning the site conceptual model. For every
site, data should be reviewed or new data
should be collected to identify factors that
could increase (or decrease) the difficulty of
restoring ground water.
-------
Hydraulics/Row Geology Contaminant Distribution Chemical Properties Site Use 3... Generalized Remediation Difficulty Scale
Site/Contaminant increasing cflfficutty
Characteristics _
Nature of Release
Small Volume Lafrfl® Volume
Slug Release Continual Release
Btotfc/Aboitic Decay
Potential
Volatility
Contaminant
Retardation (Sorph'on)
Potential
i nw • (IIB ,„.,,. .,. ..,^3- High
Contaminant Phase
Volume of
Contaminated Media
Contaminant Depth
Aqueous, Gaseous ESfr» Sorted— &* LNAPLs— |^* DNAPLs
Hydro-geologic
Characteristics ,
Stratigraphy
Texture of
Unconsolldated Deposits
Degree of Heterogeneity
Hydraulic Conductivity
of Aquifer
Temporal Variation
of Flow Regime
Vertical Row
e.g.. Planar Bedding , e.g,. Interbedded and Discontinuous
Strata
Sand • Ctay
£ '
Homogeneous Heterogeneous e.g.. intertoedojad sand and
e.g., well-sorted sand silts, days, fractured media, karst
UWo/Nono SBn. High
Little .-..-^». Large Downward Row
Component
-------
133 Assessing Restoration Potential.
Characterizing all site conditions that could
increase the difficulty of restoring ground water is
often not possible. As a result, the likelihood that
ARAR or risk-based cleanup levels can be
achieved (restoration potential) is somewhat to
highly uncertain for many sites, even alter a
relatively complete remedial investigation. This
uncertainty can be reduced by using remedy
performance in combination with site
characterization data to assess the restoration
potential. By implementing a ground-water
remedy in more than one step or phase (as two
separate actions or phasing of a single action as
described in Section 2.2), performance data from
an initial phase can be used to assess the
restoration potential and may indicate that
additional site characterization is needed. In
addition to providing valuable data, the initial
remedy phase can be used to attain short-term
response objectives, such as preventing further
plume migration. Phased implementation of
response actions also allows realistic long-term
remedial objectives to be determined prior to
installation of the comprehensive or "final"
remedy.
A detailed discussion of factors to consider for
assessing restoration potential is provided in
Guidance for Evaluating the Technical
Impracticability of Ground-Water Restoration
(EPA. 1993b; Section 4.4.4). An especially
important tool for this evaluation is the site
conceptual model, which should integrate data
from site history, characterization and response
actions. This assessment could provide
justification for waiving ARARs due to technical
impracticability from an engineering perspective
over all or portions of a site (EPA, 1993b). It is
recommended that technical assistance be enlisted
from regional technical support staff or the
Technical Support Project (EPA, 1994d) when
evaluating technical impracticability.
Data from remedy performance are not always
necessary to justify an ARAR waiver due to
technical impracticability (see Section 2.6.3).
At the completion of the remedial investigation
(RI), site conditions may have been characterized
to the extent needed for EPA (or the lead agency)
to determine that ground-water restoration is
technically impracticable from an engineering
perspective (EPA. 1993b;EPA 1995b). For this
case, an ARAR waiver request can be submitted
to EPA (or the lead agency), and if approved,
included in the Record of Decision (ROD). It will
often be appropriate to include an ARAR waiver
in the ROD for portions of a site where DNAPLs
have been confirmed in the aquifer (see Section
2.5.3).
2.0 PRESUMPTIVE RESPONSE
STRATEGY
2.1 Definition and Basis for Strategy
Key elements of the presumptive strategy are
summarized in Highlight 1. In the presumptive
response strategy, site characterization and
response actions are implemented in a several
steps, or in a phased approach. In a phased
response approach, site response activities are
implemented in a sequence of steps, or phases,
such that information gained from earlier phases is
used to refine subsequent investigations,
objectives or actions (EPA, 1989a. 1992b,
1993b).
In general for sites with contaminated ground
water, site characterization should be
coordinated with response actions and both
should be implemented in a step-by-step or
phased approach.
Performance data from an initial response action
are also used to assess the likelihood that ARAR
or risk-based cleanup levels can be attained by
later, more comprehensive actions. Although it is
recognized that phased implementation may not
be appropriate for all ground-water remedies, EPA
expects that some elements of this strategy will be
appropriate for all sites with contaminated ground
water and that all elements will be appropriate for
many of these sites. For this reason, the
response approach given in Highlight 1 is a
-------
Highlight 1. Presumptive Response
Strategy
• For sites with contaminated ground
water, site characterization
should be coordinated with
response actions and both should
• be implemented in a phased
approach (Sections 1.3.3 and 2.1).
• Early or interim actions should be
used to reduce site risks (by
preventing exposure to and further
migration of contaminants) and to
provide additional site data (Section
2.1.2).
• Site characterization and
performance data from early or
interim ground-water actions should
be used to assess the likelihood
of restoring ground water to
ARAR or risk-based cleanup levels
(restoration potential). (Sections
1.3.3 and 2.1.2.)
• The restoration potential should be
assessed prior to establishing
objectives for the long-term
remedy (Sections 1.3.3 and 2.1.2).
• All ground-water actions should
include provisions for monitoring
and evaluating their performance
(Section 2.1.3).
• Ground-water response actions,
especially those using extraction
and treatment, should generally be
implemented in more than one
phase ~ either as two separate
' actions or phasing of a single action
(Sections 2.2.1 and 2.2.2).
• In addition to phasing, post-
construction refinements will
generally be needed for long-term
remedies, especially those using
extraction and treatment (Section
2.3.1).
presumptive strategy for contaminated ground
water.
Also, this response strategy is considered
presumptive because the basic elements were
included in all previous policy directives
concerning ground-water remediation from EPA's
Office of Solid Waste and Emergency
recommended use of a phased approach for site
characterization and response actions, and more
frequent use of early actions to reduce site risks.
Better integration of site activities and more
frequent use of early actions are also essential
components of the Superfund Accelerated
Cleanup Model (SACM), defined in EPA. 1992d.
2.1.1 Benefits of Phased Approach.
Implementing investigations and actions in phases
provides the following major benefits:
® Data from earlier response actions are
used to further characterize the site and
assess restoration potential;
• Attainable objectives can be set for each
response phase;
« Flexibility is provided to adjust the
remedy in response to unexpected site
conditions;
• Remedy performance is increased,
decreasing remediation timeframe and
cost; and
• Likely remedy refinements are built into
the selected remedy, better defining the
potential scope and minimizing the need
for additional decision documents.
2.1.2 Early Actions. "Early" refers to the timing
of the start of an action with respect to other
response actions at a given site. For Superfund
sites, early actions could include removal actions,
interim remedial actions, or early final remedial
actions (EPA, 1992bandEPA, 1991b). Although
initiated prior to other actions, some early ground-
water actions may need to operate over a long time
-------
period (e.g., hydraulic containment actions). In
this guidance the later, more comprehensive
ground-water action is called the "long-term
remedy, " consistent with SACM terminology
(EPA, 1992e). Early actions that should be
considered in response to contaminated ground
water are listed in Highlight 2, categorized by
response objective. Early or interim actions
should be used to reduce site risks (by
preventing exposure to contaminated ground
.water and further migration of contaminants)
and to provide additional site data.
Factors for determining which response
components are suitable for early or interim
actions include: the timeframe needed to attain
specific objectives, the relative urgency posed by
potential or actual exposure to contaminated
ground water (e.g.. likelihood that contaminants
will reach drinking water wells), the degree to
which an action will reduce site risks, usefulness
of information to be gained from the action, site
data needed to design the action, and compatibility
with likely long-term actions (EPA, 1992e).
Whether to implement early response actions and
whether to use removal or remedial authority for
such actions should be determined by the
"Regional Decision Team" defined under SACM
(EPA, 19920 or similar decision-making body for
the site.
Early or interim actions should be integrated as
much as possible with site characterization and
with subsequent actions in a phased approach.
Once implemented,early actions willoften
provide additional site characterization
information, which should be used to update the
site conceptual model. Also, treatability studies
(see Section 3.4.5) needed for selection or design
of the long-term remedy should be combined with
early actions whenever practical. Site
characterization and performance data from early
or interim ground-water actions should be used to
assess the likelihood of restoring ground water to
ARAR or risk-based cleanup levels (restoration
potential). The restoration potential should be
assessed prior to establishing objectives for the
long-term remedy (see Section 1.3.3).
Highlight 2. Early Actions That Should
Be Considered
Prevent exposure to contaminated ground
water:
• Plume containment
• Alternate water supply
• Well head treatment
• Use restrictions
Prevent further migration of contaminant
plume:
• Plume containment
• Contain (and/or treat) plume "hot
spots"
Prevent further migration of contaminants
from sources:
• Source removal and/or treatment
" - Excavate wastes or soils
and remove from site
Excavate soils and treat ex-
situ
Treat soils in-situ
Extract free-phase NAPLs
(see Appendix A1)
• Source containment
Contain wastes or soils
- Contain subsurface NAPLs
Provide additional site data:
• Assess restoration potential
• Combine actions with treatability
studies
-------
2.1.3 Monitoring. Monitoring is needed to
evaluate whether the ground-water action is
achieving, or will achieve, the intended response
objectives for the site (see Section 1.3.1) and other
performance objectives for the action (e.g.,
discharge requirements). All ground-water
actions should include provisions for
monitoring and evaluating their performance.
A monitoring plan should be developed for both
early and long-term actions. In general, the
monitoring plan should include:
• Response objectives and performance
requirements for the ground-water action;
• Specific monitoring data to be collected;
• Data quality objectives;
• Methods for collecting, evaluating and
reporting the performance monitoring
data; and
• Criteria for demonstrating that response
objectives and performance requirements
have been attained.
Flexibility for adjusting certain aspects of
monitoring during the life of the remedy should be
included in the monitoring plan, such as changes
in the monitoring frequency as the remedy
progresses or other changes in response to remedy
refinements (see Section 2.3.1). A detailed
discussion of the data quality objectives process is
provided in EPA, 1993J. Methods for monitoring
the performance of extraction and treatment
actions are discussed in EPA, 1994e.
t
2.2 Phased Response Actions
' In general, ground-water response actions,
especially those using extraction and
treatment, should be implemented in more
than one phase. There are two options for
phasing response actions - implementation of two
separate actions, or implementation of a single
action in more than one phase. It is recognized
that phased implementation may not be
appropriate for all ground-water remedies. In
some cases, it may be more appropriate to install
the entire remedy and then remove from service
those components that later prove to be unneeded.
2.2.1 Two Separate Actions. In this approach an
early or interim ground-water action is followed
by a later, more comprehensive action (the long-
term remedy). A flow chart of this approach is
given in Figure 2. Earlier ground-water actions
are used to mitigate more immediate threats, such
as preventing further plume migration. Response
objectives for the long-term remedy are not
established until after performance of the earlier
action is evaluated and used to assess the
likelihood that ground-water restoration (or other
appropriate objectives) can be attained. Two
separate decision documents are used, in which
response objectives are specified that are
appropriate for each action. The earlier decision
document could be an Action Memorandum or an
Interim Record of Decision (Interim ROD), since
the early action could be initiated under either
CERCLA removal or remedial authority. This
approach should be used when site
characterization data are not sufficient to
determine the likelihood of attaining long-term
objectives (e.g., restoring ground water) over
ail or portions of the plume, which will be the
case for many sites. In order to provide
sufficient data for assessing the restoration
potential, the early or interim action may need to
operate for several years.
2.2.2 Phasing of a Single Action. In this
approach the long-term remedy for ground water
is implemented in more than one design and
construction phase. A flow chart of this approach
is given in Figure 3. Response objectives for the
long-term remedy are specified in a single Record
of Decision (ROD) prior to implementing the
remedy. Provisions for assessing the attainability
of these objectives using performance data from
an initial remedy phase are also included in the
ROD. Thus, phased remedy implementation and
assessment of remedy performance are specified
in one ROD. A second decision document could
still be required if evaluation of the first phase
-------
Rguta 2. Phased Ground-Water Actions: Early Action Followed by Long-Term Remedy
(this approach should be used when site characterization data are not suffltiant to determine the likelihood of attaining long-term]
I objectives (e.g.. restoring ground-water) over all or portions of Ira plume. • J
Decision
Documents
Remedy
Phase
Remedy Selection/ Implementation Steps
c
Continue Site Characterization
Interim
ROD or
Action
Maroo
Early or
Interim
Action
ROD
Memo to
Admin. Record
orESD
_L
Determine Early Action Objectives
_L
Evaluate AltemattvM.
Select Action,
Design & Construct Action
Continue SHe Characterization as
Required
Monitor Action & Evaluate Performance
Are
Data Sufficient to
Determine LiWihood of
Attaining Long-Term Objectives
(e.g., Ground-Water
Restoration)?
Comptate Remedial Investigation
_L
Determine Long-Term Objectives for
Different Portions of Plume
Evaluate Alternatives.
Select Remedy & Likely Refinements,
, Design & Construct Remedy
Long-Term
Remedy
Remedy
Refinement
Monitor Remedy & Evaluate
Performance
Select & Implement
Refinements
Monitor Remedy Unta
Objectives Attained
-------
Figure 3. Phased Ground-Water Actions: Long-Term Remedy implemented in Phases
This approach should be used when site characterization data atELSufliOfiQl to determine that the likelihood
ol attaining long-term objectives is relatively high.
Decision
Documents
Remedy
Phase
ROD
ROD
Amendment
orESD
Remedy Selection/ Implementation Steps
C Complete Remedial Investigation
Determine Long-Term Objectives for
Different Portions of Plume
Evaluate Alternatives
Select Remedy & Likely Refinements
Determine Phases 1 & II
Design & Construct Phasa 1
Monitor Phase 1 & Evaluate
Performance
Phase!
Memo to
Admin. Record
orESD
Remedy
Refinement
Are
Data Sufficient to
Determine Ukelhood of
Attaining Long-Term Objectives
(e.g., Ground-Water
Restoration)?
Are Long-Term
Objectives Attainable?
Modify Long-Term
Objectives
Evaluate Alternatives
Select Remedy
Design & Construct Phase II
Implement Changes
Monitor Remedy & Evaluate
Performance
Select & Implement
Refinements
Are Refinements Needed?
Monitor Remedy Until
Objectives Attained
10
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indicates that long-term objectives or other
aspects of the remedy require modification, and
the modified remedy differs significantly from the
selected remedy in terms of scope, performance or
cost (EPA, 199la). This approach should be
used when site characterization data indicate
that the likelihood of attaining long-term
objectives is relatively high.
When phased remedy implementation is specified
in a ROD, the Agency should ensure that the
proposed plan contains sufficient information
regarding the nature, scope timing and basis of
future decision points and alternatives that the
public is able to evaluate and comment on the
proposed remedy. Example language illustrating
how such an approach can be specified in the
selected remedy portion of the ROD is included in
Appendices Bl and B2 for hypothetical sites.
These examples follow the suggested ROD
language given in EPA, 1990b, although the
wording has been updated to reflect thus and other
recent guidance (EPA, 1993b). For comparison,
suggested ROD language from the EPA, 1990b is
included as Appendix B4.
Phased implementation of a remedy can often be
beneficial even for relatively simple ground-water
actions! For example, one extraction well could
be installed as the initial phase and the
performance of this well would be used to
determine whether any additional wells are needed
and whether long-term objectives need to be re-
evaluated.
Phased implementation of an extraction and
treatment remedy will require that the treatment
system be designed to accommodate phased
installation of the extraction system. Presumptive
technologies for the treatment system and other
design considerations are discussed in Section 3.
Use of modular treatment components, which can
be easily added or removed from the treatment
system, may facilitate phased implementation or
other changes in flow or contaminant
concentration that may occur during the life of a
remedy. Another approach is to design the
treatment system for the higher flows expected
from all phases of the extraction system. Some
components of the remedy, such as buried
portions of the piping distribution system, are
difficult to install in phases and should be
designed to carry the highest expected flows.
23 Post-Construction Refinements
Even after phased implementation of a ground-
water remedy, post-construction refinements will
generally be needed because of the long time
period over which the remedy will operate,
especially for extraction and treatment remedies.
The refinement portion of the long-term remedy,
after phased design and construction, is shown in
both Figures 2 and 3.
23.1 Types of Refinements. Post-construction
refinements that should be considered for
extraction and treatment remedies are given in
Highlight 3. These refinements are intended to be
relatively minor changes to the remedy (i.e., for
which an Explanation of Significant Differences
(ESD) or ROD Amendment would generally not
be required). For example, adding a new
extraction or reinjection well, or a few additional
monitoring wells should be considered a minor
modification to a remedy that includes a relatively
large number of such wells, because the overall
scope, performance and cost of the remedy are not
significantly changed (EPA, 1991 a). One or more
such refinements should generally be implemented
when the results of a remedy evaluation indicate
that they are needed to increase the performance
of the remedy or to decrease the remediation
timeframe.
23.2 Documenting Refinements. Potential post-
construction refinements should be included in the
ROD as part of the selected remedy. Listing
specific remedy refinements in the ROD serves to
communicate the anticipated full scope of the
remedy to all concerned parties at an early date,
and also minimizes the likelihood that a
subsequent ESD or ROD Amendment will be
needed. When remedy refinements are specified
in a ROD, the Agency should ensure that the
11
-------
Highlight 3. Remedy Refinements for
Extraction/Treatment Remedies
• Change the extraction rate in some
or all wells.
• Cease extraction from some wells.
• Initiate "pulsed pumping" (see
Appendix A4).
• Add or remove extraction or
reinjection wells, or drains.
• Add or remove monitoring wells.
• Refine source control components
of remedy.
• Refine enhanced recovery or in-situ
degradation components of remedy
(see Note).
• Refine ex-situ treatment
components
NOTE: A ground-water remedy could
include both extraction and treatment and in-
s'rtu treatment methods.
proposed plan contains sufficient information
regarding the nature, scope timing and basis of
future decision points and alternatives that the
public is able to evaluate and comment on the
proposed remedy. Example ROD language
specifying likely post-construction refinements for
the extraction portion of the selected remedy is
given in Appendices B1 and B2. Even if an ESD
is not required, a letter or memorandum should be
included in the post-ROD portion of the
Administrative Record explaining the minor
remedy modifications and the reasons for them.
Additional information concerning documentation
of remedy modifications can be found in the EPA
fact sheet entitled Guide to Addressing Pre-ROD
and Post-ROD Changes (EPA, 1991 a).
2.4 Integrating Response Actions
In general, actions in response to contaminated
ground water should be planned and implemented
as part of an overall strategy. Earlier actions (see
Highlight 2 for examples) should be compatible
with and not preclude implementation of later
actions. For example, permanent facilities should
not be constructed which could interfere with
possible later actions (e.g., structures that would
interfere with later construction of extraction wells
or of a cap).
2.4.1 Integrating Source Control and Ground-
Water Actions. Restoration of contaminated
ground water generally will not be possible unless
contaminant sources have been controlled in some
manner. Source control is a critical component for
active restoration remedies (e.g., extraction and
treatment and in-situ methods) as well as for
natural attenuation (defined in Section 2.6.5).
Selection of appropriate source control actions
should consider whether other contaminant
sources.(i.e.. NAPLs) are likely to be present in
additioato contaminated soils. If NAPLs are
present, the vast majority of contaminant mass
will likely reside in the subsurface NAPLs rather
than in the surficial soils. Therefore, for this case
source control actions that are intended to
minimize further contamination of ground water
should focus on controlling migration of
contaminants from the subsurface NAPLs. Also,
capping or treatment of surficial soils may be
needed to prevent exposure to contaminants from
direct soil contact or inhalation, but these actions
alone would be ineffective in preventing further
contamination of ground water at sites where
NAPLs are present.
2.4.2 Combining Ground-Water Restoration
Methods. A remedy could include more than one
method for restoring ground water to its beneficial
uses, such as combining extraction and treatment
with natural attenuation or in-situ-treatment with
extraction and treatment. Extraction and
treatment is especially useful for providing
hydraulic containment of those portions of the
12
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plume where contaminant sources are present
(e.g., subsurface NAPLs or contaminated soils), or
for containing or restoring those plume areas with
relatively high concentrations of dissolved
contamination ("hot spots"). However, extraction
and treatment may not be the best method for
restoring large areas of the plume with low
contaminant levels.
Once source areas are controlled, natural
attenuation may be able to restore large
portions of the plume to desired cleanup levels
in a timeframe that is reasonable (see Section
2.6.2) when compared with the timefrairase and
cost of other restoration methods. Thus,
natural attenuation of some plume areas combined
with extraction and treatment to contain source
areas and/or plume "hot spots" may be the most
appropriate restoration approach for many sites
with relatively large, dilute plumes. Whether or
not natural attenuation is used alone or combined
with other remediation methods, the Agency
should have sufficient information to demonstrate
that natural processes are capable of achieving the
remediation objectives for the site. EPA is
currently preparing a directive that will provide
more detailed discussion of EPA policy regarding
the use of natural attenuation for remediation of
contaminated ground water (EPA. 1996c).
By combining in-situ treatment and extraction and
treatment methods it may be possible to
significantly increase the effectiveness with which
contaminants are removed from the aquifer. In
this guidance, in-situ treatment methods for
ground water are divided into two types:
, • . Methods that can be used to enhance
contaminant recovery during extraction
and treatment (e.g., water, steam or
chemical flooding; hydraulic or pneumatic
fracturing); and
• Methods for in-situ degradation of
contaminants generally involve adding
agents to the subsurface (i.e., via wells or
treatment walls) which facilitate chemical
or biological destruction, and have the
potential to be used as an alternative to
extraction and treatment for long-term
restoration of ground water.
Examples of both types of in-situ treatment
methods are given in Appendix A3. Reinjection
of treated ground water can be used as a method
for enhancing contaminant recovery as well as a
discharge method, if the reinjection is designed for
this purpose as part of an extraction and treatment
remedy. When considering enhanced recovery
methods for sites with subsurface NAPLs,
potential risks of increasing the mobility of
NAPLs should be evaluated. Methods of in-situ
degradation of contaminants most frequently used
at Superfund sites include air sparging, various
types of in-situ biological treatment and
permeable treatment walls or gates (EPA, 1995e).
Additional information concerning air sparging
and permeable treatment walls is available in
EPA. 1995fandEPA, 1995d. respectively. EPA
encourages the consideration, testing and use of
in-situ technologies for ground-water remediation
when appropriate for the site.
2.5 Strategy for DNAPL Sites
Dense nonaqueous phase liquids (DNAPLs) pose
special cleanup difficulties because they can sink
to great depths in the subsurface, continue to
release dissolved contaminants to the surrounding
ground water for very long time periods, and can
be difficult to locate. Due to the complex nature
of DNAPL contamination, a phased approach to
characterization and response actions is especially
important for sites where DNAPLs are confirmed
or suspected. A recent EPA study concluded that
subsurface DNAPLs may be present at up to 60
percent of CERCLA National Priorities List sites
(EPA, 1993c). Refer to Appendix A1 for
additional background information on DNAPLs.
Two types of subsurface contamination can be
defined at DNAPL sites, the:
• DNAPL zone, and the
• Aqueous contaminant plume.
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The DNAPL zone is that portion of the
subsurface where immiscible liquids (free-phase
or residual DNAPL) are present either above or
below the water table. Also in the DNAPL zone,
vapor phase DNAPL contaminants are present
above the water table and dissolved phase below
the water table. The aqueous contaminant
plume is that portion of the contaminated ground
water surrounding the DNAPL zone where
aqueous contaminants derived from DNAPLs are
dissolved in ground water (or sorbed to aquifer
solids) and immiscible liquids are not present.
2.5.1 Site Characterization. If DNAPLs are
confirmed or suspected, the remedial investigation
(RI) should be designed to delineate the:
• Extent of aqueous contaminant plumes,
and the
• Potential extent of DNAPL zones.
Methods and strategies for characterizing DNAPL
sites as well as suggested precautions are
discussed in other guidance (EPA, 1992a and
1994b) and by Cohen and Mercer, 1993. The
reason for delineating these areas of the site is that
response objectives and actions should generally
be different for the DNAPL zone than for the
aqueous contaminant plume. It is recognized that
for some sites complete delineation of the
DNAPL-zone may not be possible.
2£.2 Early Actions. The early actions listed in
Highlight 2 should be considered. Also, the
following early actions are specifically
recommended for DNAPL sites (EPA 1992b,
1993b):
• Prevent further spread of the aqueous
plume (plume containment);
• Prevent further spread of hot spots in the
aqueous plume (hot spot containment);
« Control further migration of contaminants
from subsurface DNAPLs to the
surrounding ground water (source
control); and
« Reduce the quantity of source material
(free-phase DNAPL) present in the
DNAPL zone, to the extent practicable
(source removal and/or treatment).
At DNAPL sites, hot spots in the aqueous plume
often are associated with subsurface DNAPLs.
Therefore, the second and third actions listed
above are essentially the same.
2.5 J Long-Term Remedy. The long-term
remedy should attain those objectives listed above
for the DNAFL zone, by continuing early actions
or by initiating additional actions. Although
contaminated ground waters generally are not
considered principal threat wastes, DNAPLs
may be viewed as a principal threat because they
are sources of toxic contaminants to ground water
(EPA, 1991c). For this reason EPA expects to
remove or treat DNAPLs to the extent practicable
in accordance with the NCP expectation to "use
treatment to address the principal threats posed by
a site, wherever practicable" (Federal Register.
1990a; §300.430 (a)(l)(iii)(A)). However,
program experience has shown that removal of
DNAPLs from the subsurface is often not
practicable, and no treatment technologies are
currently available which can attain ARAR or
risk-based cleanup levels where subsurface
DNAPLs are present. Therefore, EPA generally
expects that the long-term remedy will control
further migration of contaminaiats from
subsurface DNAPLs to the surrounding
ground water and reduce the quantity of
DNAPL to the extent practicable.
For the aqueous pSume, the long-term remedy
should:
• Prevent further spread of the aqueous
plume (plume containment);
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• Restore the maximum areal extent of the
aquifer to those cleanup levels
appropriate for its beneficial uses (aquifer
restoration).
In general, restoration of die aquifer to ARAR
or risk-based cleanup levels in a reasonable
timeframe will not be attainable in the DNAPL
zone unless the DNAPLs are removed. For this
reason, it is expected that ARAR waivers due to
technical impracticability will be appropriate for
many DNAPL sites, over portions of sites where
non-recoverable DNAPLs are present (EPA,
1995c). Also, EPA generally prefers to utilize
ARAR waivers rather than ARAR compliance
boundaries for such portions of DNAPL sites (see
Section 2.6.4). A waiver determination can be
made after construction and operation of the
remedy or at the time of remedy selection (i.e., in
the ROD), whenever a sufficient technical
justification can be demonstrated (EPA, 1993b;
EPA 1995b). For further information refer to
Section 2.6.3 of this guidance and EPA's
Guidance for Evaluating the Technical
Impracticability of Ground- Water Restoration •
(EPA, 1993b). Restoration of the aqueous plume
may also be difficult due to hydrogeologic factors,
such as sorption of dissolved contaminants to
solids in finer grained strata. For some sites,
ARAR waivers may also be appropriate for all or
portions of the aqueous plume when supported by
adequate justification.
2.6 Areas of Flexibility in Cleanup Approach
The current response approach to contaminated
ground water, as defined in the NCP and other
guidance, includes several areas of flexibility in
which response objectives and the timeframe in
which to meet them can be adjusted to meet site
specific conditions. These are briefly discussed
below.
2.6.1 Beneficial Uses and ARARs. Since EPA
generally expects to return contaminated ground
waters to their beneficial uses wherever
practicable, the required cleanup levels for a given
site should be determined from applicable or
relevant and appropriate requirements (ARARs)
based on the current and expected future
beneficial uses of the ground water at that site.
Depending on state requirements and water
quantity or quality characteristics, some ground
waters are not expected to provide a future source
of drinking water (e.g., EPA Class HI ground
waters (EPA, 1986) or similar state designations).
In general, drinking water standards are relevant
and appropriate cleanup levels for ground waters
that are a current or future source of drinking
water, but are not relevant and appropriate for
ground waters that are not expected to be a future
source of drinking water (Federal Register, 1990a;
Preamble at 8732). (Drinking water standards
include federal maximum contaminant levels
(MCLs) and/or non-zero maximum contaminant
level goals (MCLGs) established under the Safe
Drinking Water Act, or more stringent state
drinking water standards.) Ground waters may
have other beneficial uses, such as providing base
flow to surface waters or recharging other
aquifers. For contaminated ground waters that
discharge to surface water, water quality criteria
established under the Clean Water Act. or more
stringent state surface water requirements, may
also be cleanup level ARARs (Federal Register,
I990a; Preamble at 8754). Thus, the beneficial
uses of contaminated ground water at a particular
site will generally provide the basis for
determining which federal or state environmental
requirements are applicable or relevant and
appropriate cleanup levels. For additional
information on the determination of cleanup
levels, refer to EPA, 1988b, Chapter 4.
Determination of current and expected future
beneficial uses should consider state ground-water
classifications or similar designations. Several
states have developed ground-water use or priority
designations as part of a Comprehensive State
Ground Water Protection Program (CSGWPP),
defined in EPA, 1992h. EPA is currently
developing a directive (EPA, 1996a) which will
recommend that EPA remediation programs
should generally defer to state determinations of
future ground-water use « even when this
determination differs from the use that would
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otherwise have been determined by EPA ~ when
such determinations are:
• , Developed as part of an CSG WPP that is
endorsed by EPA, and
• Based on CSGWPP provisions that can
be applied at specific sites (EPA, 1996a).
This provision of the directive, when final, is
intended to supersede previous guidance contained
in the Preamble to the NCP (Federal Register,
1990a; at 8733). Refer to EPA. 1996a for
additional information concerning the role of
CSGWPPs in the selection of ground-water
remedies. When information concerning
beneficial uses is not available from a CSGWPP,
ground-water classifications defined in EPA, 1986
(i.e., EPA Classes I. n or HI) or "more stringent"
state ground-water classifications (or similar state
designations) should generally be used to
determine the potential future use, in accordance
with the NCP Preamble (Federal Register, 1990a;
at 8732-8733). Regardless of the ground-water
use determination, remedies selected under
CERCLA authority must protect human
health and the environment and meet ARARs
(or invoke an ARAR waiver).
Many states have antidegradation or similar
regulations or requirements that may be potential
ARARs. Such requirements typically focus on 1)
prohibiting certain discharges, 2) maintaining
ground-water quality consistent with its beneficial
uses, or 3) maintaining naturally occurring
(background) ground-water quality. Regulations
of the third type do not involve determination of
future ground-water use, and often result in
cleanup levels that are more stringent than the
drinking water standard for a particular chemical.
Such requirements are potential ARARs if they
are directive in nature and intent and established
through a promulgated statute or regulation that is
legally enforceable (see Federal Register, 1990a;
Preamble at 8746). For further information
concerning issues related to state ground-water
antidegradation requirements, refer to EPA
I990a.
2.6.2 Remediation Timeframe. "Remediation
timeframes will be developed based on the
specific site conditions" (Federal Register, 1990a;
Preamble at 8732). Even though restoration to
beneficial uses generally is the ultimate objective,
a relatively long time period to attain this
objective may be appropriate for some sites. For
example, an extended remediation timeframe
generally is appropriate where contaminated
ground waters are not expected to be used in the
near term, and where alternative sources are
available. In contrast, a more aggressive remedy
with a correspondingly shorter remediation
timeframe should generally be used for
contaminated ground waters that are currently
used as sources of drinking water or are expected
to be utilized for this purpose in the near future
(Federal Register, 1990a; at 8732). A state's
CSGWPP may include information helpful in
determining whether an extended remediation
timeframe is appropriate for a given site, such as
the expected timeframe of use, or the relative
priority or value of ground-water resources in
different geographic areas.
*•
A reasonable tuneframe for restoring ground
waters to beneficial uses depends on the particular
circumstances of the site and the restoration
method employed. The most appropriate
timeframe must be determined through an analysis
of alternatives (Federal Register, I990a; Preamble
at 8732). The NCP also specifies that:
"For ground-water response actions, the
lead agency shall develop a limited
number of remedial alternatives that
attain site-specific remediation levels
within different restoration time periods
utilizing one or more different
technologies." (Federal Register, 1990a;
§300.430(e)(4).)
Thus, a comparison of restoration alternatives
from most aggressive to passive (i.e., natural
attenuation) will provide information concerning
the approximate range of time periods needed to
attain ground-water cleanup levels. An
excessively long restoration timeframe, even with
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the most aggressive restoration methods, may
indicate that ground-water restoration is
technically impracticable from an engineering
perspective (see Section 2.6.3). Where restoration
is feasible using both aggressive and passive
methods, the longer restoration timeframe
required by a passive alternative may be
reasonable in comparison with the timeframe
needed for more aggressive restoration
alternatives. The most appropriate remedial
option should be determined based on the nine
remedy selection factors defined in the NCP
(Federal Register, ,1990a; §300.430 (eK9)(iii)).
Although restoration timeframe is an important
consideration in evaluating whether restoration of
ground water is technically impracticable, no
single time period can be specified which would
be considered excessively long for all site
conditions (EPA, 1993b). For example, a
restoration timeframe of 100 years may be
reasonable for some sites and excessively long for
others.
2.63 Technical Impracticability. Where
restoration of ground water to its beneficial uses is
not practicable from an engineering perspective.
one or more ARARs may be waived by EPA (or
the lead agency) under the provisions defined in
CERCLA § 121 (d)(4)(Q). The types of data used
to make such a determination are discussed in
Guidance for Evaluating the Technical
Impracticability of Ground-Water Restoration
(EPA, 1993b). Alternative remedial strategies, to
be considered when restoration ARARs are
waived, are also discussed in EPA, 1993b. A
finding of technical impracticability may be made
in the Record of Decision (ROD) prior to remedy
implementation, or in a subsequent decision
document after implementation and monitoring of
remedy performance.
2.6.4 Point of Compliance. The area over which
ARAR or risk-based cleanup levels are to be
attained is defined in the NCP as follows:
"For ground water, remediation levels
should generally be attained throughout
the contaminated plume, or at and beyond
the edge of the waste management area
when waste is left in place" (Federal
Register, 1990a; Preamble at 8713).
Thus, the edge of the waste management area can
be considered as the point of compliance, because
ARAR or risk-based cleanup levels are not
expected to be attained in ground water within the
waste management area. In general, the term
"waste left in place" is used in the NCP to refer to
landfill wastes that, at the completion of the
remedy, will be contained or otherwise controlled
within a waste management area.
For the purposes of ARAR compliance, EPA
generally does not consider DNAPLs as "waste
left in place." DNAPLs are typically not located
in a waste management area, as envisioned in the
NCP. This is because the full extent of DNAPL
contamination is often not known, DNAPLs can
continue to migrate in the subsurface, and
measures for controlling their migration are either
unavailable or have uncertain long-term reliability.
Also, as discussed in Section 2.5.3, restoration of
the aquifer to ARAR or risk-based cleanup levels
generally will not be attainable in a reasonable
timeframe unless the DNAPLs are removed. For
these reasons, EPA generally prefers to utilize
AEAR waivers rather than an alternate point
of compliance over portions of sites where non-
recoverable DNAPLs are present in the
subsurface (EPA, 1995c).
The NCP Preamble also acknowledges that "an
alternative point of compliance may also be
protective of public health and the environment
under site-specific circumstances" (Federal
Register, 1990a; at 8753). For example, where
the contamination plume is "caused by releases
from several distinct sources that are in close
geographical proximity...the most feasible and
effective cleanup strategy may be to address the
problem as a whole, rather than source by source,
and to draw the point of compliance to encompass
the sources of release" (Federal Register, 1990a;
at 8753). The NCP Preamble goes on to say that
"...where there would be little likelihood of
exposure due to the remoteness of the site,
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alternate points of compliance may be considered,
provided contamination in the aquifer is controlled
from further migration" (Federal Register, 1990a;
at 8734). The Agency has not developed
additional guidance on the use of alternate points
of compliance at Superfund sites.
2.6.5 Natural Attenuation. Natural attenuation
is defined in the NCP as "biodegradation,
dispersion, dilution, and adsorption" of
contaminants in ground water (Federal Register,
1990a; Preamble at 8734). The NCP goes on to
explain that natural attenuation may be a useful
remedial approach if site-specific data indicate
that these processes "will effectively reduce
contaminants in the ground water to
concentrations protective of human health [and the
environment] in a timeframe comparable to that
which could be achieved through active
restoration." This approach differs from the "no
action" alternative because natural attenuation is
expected to attain cleanup levels in a reasonable
timeframe (discussed in Section 2.6.2). The NCP
recommends use of natural attenuation where it is
"expected to reduce the concentration of
contaminants in the ground water to the
remediation goals [ARAR or risk-based cleanup
levels] in a reasonable timeframe."
Natural attenuation may be an appropriate
remedial approach for portions of the contaminant
plume when combined with other remedial
measures needed to control sources and/or
remediate "hot spots" (also see Section 2.4.2).
Whether or not natural attenuation is used alone or
combined with other remediation methods, the
Agency should have sufficient information to
demonstrate that natural processes are capable of
achieving the remediation objectives for the site.
One caution is that natural attenuation may not be
appropriate for sites where contaminants
biodegrade to intermediate compounds that are
more toxic and degrade more slowly.
Additional EPA policy considerations regarding
the use of natural attenuation for remediation of
contaminated ground water are provided in EPA,
1996c. Although currently in draft, this EPA
directive recommends that remedies utilizing
natural attenuation should generally include: 1)
detailed site characterization to show that this
approach will be effective; 2) source control
measures to prevent further release of
contaminants to ground water; 3) performance
monitoring to assure that natural attenuation is
occurring as expected; and 4) institutional
controls and other methods to ensure that
contaminated ground waters are not used before
protective concentrations are reached. Also,
contingency measures may be needed in the
event that natural attenuation does not progress as
expected.
2.6.6 Alternate Coocentratioa Limits.
Alternate concentration limits (ACLs) are
intended to provide flexibility in establishing
ground-water cleanup levels under certain
circumstances. In the Superfund program, EPA
may establish ACLs as cleanup levels in lieu of
drinking water standards (e.g., MCLs) in certain
cases where contaminated ground water
discharges to surface water. The circumstances
under which ACLs may be established at
Superfund sites are specified in CERCLA
§ 121 (d)(2)(B)(iiX and can be summarized as
follows:
* The contaminated ground water must
have "known or projected" points of entry
to a surface water body;
• There must be no "statistically significant
increases" of contaminant concentrations
in the surface water body at those points
of entry, or at points downstream; and
® It must be possible to reliably prevent
human exposure to the contaminated
ground water through the use of
institutional controls.
Each of these criteria must be met and must be
supported by site-specific information. Such
information also must be incorporated into the
appropriate portions of the Administrative Record
(e.g., the RI/FS and ROD).
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The NCP Preamble also advises that ACLs not be
used in every situation in which the above
conditions are met, but only where active
restoration of the ground water is "deemed not to
be practicable" (Federal Register, 1990a; at
8754). This caveat in the Preamble signals that
EPA is committed to the program goal of
restoring contaminated ground water to its
beneficial uses, except in limited cases. In the
context of determining whether ACLs could or
should be used for a given site, the term
"practicability" refers to an overall finding of the
appropriateness of ground-water restoration,
based on an analysis of remedial alternatives using
the Superfund remedy selection criteria, especially
the "balancing" and "modifying" criteria (EPA,
1993b). (These criteria are defined in pact
§300.430(e)(9)(iii) of the NCP (Federal Register,
1990a.) This is distinct from a finding of
"technical impracticability from an engineering
perspective," which refers specifically to an
ARAR waiver and is based on the narrower
grounds of engineering feasibility and reliability
with cost generally not a major factor, unless
ARAR compliance would be inordinately costly
(see Section 2.6.3 and EPA, 1993b). Where an
ACL is established, such an ARAR waiver is not
necessary. Conversely, where an ARAR is waived
due to technical impracticability, there is no need
to establish CERCLA ACLs, as defined above.
When establishing an ACL, a detailed site-specific
justification should be provided in the
Administrative Record which documents that the
above three conditions for use of ACLs are met,
and that restoration to ARAR or risk-based levels
is "not practicable" as discussed above.
Although alternate concentration limits are also
defined in the RCRA program, users of this
guidance should be aware of several important
differences in the use of ACLs by the RCRA
and Superfund programs. For "regulated units"
(defined in 40 CFR 264.90) ACLs are one of the
three possible approaches for establishing
concentrations limits of hazardous constituents in
ground water. Those options are described in 40
CFR 294.94(a). Factors considered when
determining whether an ACL is appropriate for a
particular facility are provided in 40 CFR
264.94(b). The use of RCRA ACLs is not strictly
limited to cases where contaminated ground water
discharges to surface water, or to cases where
ground-water restoration is considered "not
practicable" (as is the case in Superfund).
However, the factors considered in the RCRA
ACL decision are meant to ensure that
establishment of ACLs will be protective of
human health and the environment. .
A specific reference to ACLs is not made in the
existing framework for implementing RCRA
Corrective Action at "non-regulated units"
(Federal Register, 1990b and 1996). However,
the Corrective Action framework recommends
flexibility for the development and use of risk-
based cleanup standards, based on considerations
similar to those used for establishing ACLs under
40 CFR 264.94.
3.0 PRESUMPTIVE TECHNOLOGIES
3.1 Presumptive Technologies for Ex-Situ
Treatment
Presumptive technologies for the treatment
portion of an extraction and treatment remedy (ex-
situ treatment) are identified in Highlight 4.
Descriptions of each of the presumptive
technologies are presented in Appendices Dl
through D8. These technologies are presumptive
for treatment of contaminants dissolved in
ground water that has been extracted from the
subsurface, and are expected to be used for this
purpose at "all appropriate sites." (Refer to the
Preface of this guidance and EPA, 1993d for
further information concerning the Agency's
expectations concerning the use of presumptive
treatment technologies.)
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Highlight 4. Presumptive Technologies
For Treatment Of Extracted Ground
Water
For treatment of dissolved organic
contaminants, volatiies, semK/olatiles and
others (see Note):
• Air stripping
• Granular activated carbon (GAC)
• Chem tcal/UV oxidation (for cyanides
also)
• Aerobic biological reactors
For treatment of dissolved metals:
• Chemical precipitation
• Ion exchange/adsorption
• Electrochemical methods (when
only metals are present)
• Aeration of background metals
For treatment of both organic and
Inorganic constituents:
• A combination of the technologies
listed above
NOTE: A given treatment train could include
a combination of one or more of the
presumptive technologies for treatment of
dissolved contaminants as well as other
technologies for other purposes (e.g.,
separation of solids) as indicated in
Appendix C2.
3.1.1 Design Styles within Presumptive
Technologies. The presumptive technologies
identified in Highlight 4 refer to technology types
rather than specific designs (design styles). Each
presumptive technology represents a single
process falls within one of these technology types
(e.g., innovative air stripper designs, or
innovative media for ion exchange/adsorption of
metals). A listing of design styles of the
presumptive technologies typically considered
during Superfund remedy selection are listed in
Appendix Cl.
3.1.2 Benefits of Presumptive Technologies.
Use of the presumptive technologies identified in
this guidance will simplify and streamline the
remedy selection process for the ex-situ treatment
portion of a ground-water remedy by:
• Simplifying the overall selection process,
since the large number and diverse
assortment of these technologies have
been reduced to relatively few technology
types;
® Eliminating the need to perform the
technology screening portion of the
feasibility study (FS), beyond the analysis
contained in this guidance and its
associated Administrative Record. (See
Section 3.3.2);
• Allowing, in some cases, further
consideration and selection among the
presumptive technologies to be deferred
from the FS and ROD to the remedial
design (RD), which prevents duplication
of effort and allows selection to be based
on additional data collected during the RD
(see Section 3.3.3);
• Shifting the time and resources employed
in remedy selection from ex-situ
treatment to other, more fundamental
aspects of the ground-water remedy (see
Section 1.0); and
• Facilitating the use of extraction and
treatment for early actions, where
appropriate, since selection of the
treatment component is simplified:
3.13 Consideration of Innovative
Technologies. Use of presumptive technologies
for treatment of extracted ground water is
intended to simplify the remedy selection process,
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but does not preclude the consideration of
innovative technologies for this purpose in the FS
or RD. Refer to the EPA fact sheet. Presumptive
Remedies: Policy and Procedures (EPA, 1993d),
for additional information. Many innovative or
emerging technologies for ex-situ treatment are
actually design variations of one of the
presumptive technology types, as discussed above,
and others may be considered on a site-specific
basis. In addition, EPA encourages consideration
of in-situ treatment technologies for ground-water
remedies, either when combined with extraction
and treatment or as an alternative to such methods
(see Section 2.4.2).
3.2 Basis for Presumptive Technologies
3.2.1 Sources of Information. Three sources of
information were used to determine which
technologies should be identified as presumptive
for ex-situ treatment of ground water:
« Review of the technologies selected in aU
RODs signed from fiscal years 1982
, through 1992;
• Review of capabilities and limitations of
ex-situ treatment technologies from
engineering and other technical literature;
and
• Detailed evaluation of the technologies
considered in the FS and selected in the
ROD or RD for a sample of 25 sites for
which at least one ex-situ treatment
technology was selected.
The .above information is summarized in a
separate report entitled Analysis of Remedy
Selection Results for Ground-Water Treatment
Technologies at CERCLA Sites (EPA, 1996b). A
total of 427 RODs selected at least one ex-situ
technology for treatment of ground water, as of
September 30, 1992. From these RODs, a sample
of 25 sites were selected for detailed evaluation of
the rationale used to select these technologies as
part of the ground-water remedy.
3.2.2 Rationale for Indentifying Presumptive
Technologies. At least one of the eight
presumptive technologies, identified in Highlight
4, was selected as part of the ground-water remedy
in 425 of 427 RODs, or 99.5 percent of the time.
In only five RODs were technologies other than
the presumptive technologies selected as part of
the treatment train. Therefore, presumptive
technologies were the only technologies selected
for ex-situ treatment of dissolved ground-water
contaminants in 420 of the 427 RODs.
More importantly, all the presumptive
technologies are well understood methods that
have been used for many years in the
treatment of drinking water and/or municipal
or industrial wastewater. Engineering Bulletins
or Technical Data Sheets have been developed by
EPA and the Naval Energy and Environmental
Support Activity, respectively, for five of the eight
presumptive technologies. These publications
generally include site specific performance
examples, and are included as references, along
with other publications, with the description of
each .technology in Appendix D.
In the 25 site sample, the presumptive
technologies, identified in Highlight 4. were the
only technologies selected in the ROD for all sites
and the only technologies implemented in the RD
for 24 sites. Other technologies were consistently
eliminated from further consideration, usually in
the technology screening step, based on technical
limitations which were verified by the engineering
literature. As part of this evaluation the large
number and diverse assortment of technologies
considered for ex-situ treatment of ground water
were categorized according to the underlying
treatment process. A complete listing of the
technologies considered in the FS, ROD or RD for
the 25 sites is given in Appendix Cl, categorized
by process type and with the presumptive
technologies identified.
Some technologies are identified as presumptive
even though they were selected in relatively few
RODs. Aeration of background metals was
identified as presumptive because this technology
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is often used for removal of iron and manganese,
and was considered and selected for this purpose
at two of the 25 sample sites. Electrochemical
methods for metals removal were also identified
as presumptive because these methods were
considered at all three sample sites where metals
were the only contaminants of concern, and were
selected at two of these sites. Chemical/UV
oxidation and aerobic biological reactors were
identified as presumptive technologies for treating
organic contaminants for the following technical
reasons:
A range of chemical, physical and
biological treatment methods should be
included in the presumptive technologies,
because air stripping and granular
activated carbon, alone or combined, may
not provide cost effective treatment (see
Section 3.4.5) for all organic
contaminants.
These methods destroy organic
contaminants as part of the treatment
process instead of transferring them to
other media, which reduces the quantity
of hazardous treatment residuals (e.g.,
spent carbon) that will require further
treatment.
Ongoing research and development
efforts, by EPA and others, are expected
to increase the cost effectiveness of these
treatment methods.
3.3 Remedy Selection Using Presumptive
Technologies
Selection of technologies for long-term treatment
of extracted ground water requires an
understanding of the types of technologies that
will be needed, how they will be used in the
treatment system and site-specific information for
determining the most appropriate and cost-
effective technologies. The presumptive
technologies for treating dissolved
contaminants in extracted ground water,
identified in Highlight 4, are the technologies
that should be retained for further
consideration in the Detailed Analysis portion
of the feasibility study (FS). This guidance and
its associated Administrative Record will
generally constitute the Development and
Screening of Alternatives portion of the FS for the
ex-situ treatment component of a ground-water
remedy, as discussed in Section 3.3.2.
Site information needed to select cost-effective
treatment technologies (see Section 3..4) is often
not collected until the remedial design (RD) phase.
Ira such cases, it will generally be appropriate
to specify performance requirements for the
treatment system in the ROD, but defer
selection of specific technologies until the ED,
as discussed in Section 3.3.3.
3 J.I Use of Technologies in Treatment
Systems. Complete treatment of extracted ground
water generally requires that units of more than
one technology, or multiple units of a single
technology (unit processes), be linked together in
a treatment train. A given treatment train could
include some combination of treatment
technologies for the following purposes:
1. Separation of mineral solids and/or
immiscible liquids from the extracted
ground water during initial treatment
(pretrealment);
2. Treatment of dissolved contaminants;
3. Treatment of vapor phase contaminants
from the extracted ground water or those
generated during treatment;
4. Separation of solids generated during
treatment;
5. Final treatment of dissolved
contaminants prior to discharge
(polishing); and
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5. Treatment of solids generated during
treatment.
Presumptive technologies for treatment of
Dissolved contaminants in extracted ground
water (No. 2 and 5. above) are identified in
Highlight 4. Examples of the types of
technologies used for other purposes are given in
Appendix C2, along with a Listing of the general
sequence of unit processes used in a treatment
train. Solid residuals (such as sludges from
chemical or biological processes, or spent carbon
media) will generally require additional treatment
or disposal, either as part of the treatment train or
at a separate facility. Presumptive technologies
for purposes other than for treatment of dissolved
contaminants have not been identified in this
guidance.
Use of modular treatment components, which can
be easily added or removed from the treatment
system, may facilitate phased implementation or
other changes that may occur during the life of a
remedy. Phased implementation of the extraction
portion of a remedy may require that some
components of the treatment system also be
installed in stages. Also, modification of the
treatment system over time may be needed in
response to changes in the inflow rate or
contaminant loadings, or to increase the
effectiveness or efficiency of the treatment system.
3.3.2 This Guidance Constitutes the fS
Screening Step. This guidance and its associated
Administrative Record will generally constitute
the "development and screening of alternatives"
portion of the feasibility study (FS), for the ex-situ
treatment component of a ground-water remedy.
When using presumptive technologies, the FS
should contain a brief description of this approach
(see fact sheet entitled Presumptive Remedies:
Policy and Procedures (EPA, 1993d)), and refer
to this guidance and its associated Administrative
Record. Such a brief description should fulfill the
need for the development and screening of
technologies portion of the FS for the ex-situ
treatment component of the remedy.
33 J Deferral of Final Technology Selection to
RD. Although EPA prefers to collect the site
information needed for technology selection prior
to the ROD, it is sometimes impracticable to
collect some of the necessary information until the
remedial design (RD) phase. (See Section 3.4 for
a summary of site information generally needed
for selection of these technologies.) In reviewing
remedy selection experience for a sample of sites,
EPA found that at seven of 25 sites (28 percent)
the type of technology selected in the ROD for
treatment of extracted ground water was later
changed in the RD because of additional site
information obtained during the design phase
(EPA, 1996b). Where EPA lacks important
information at the ROD stage, it may be
appropriate to defer final selection among the
presumptive ex-situ treatment technologies (as
well as selection of specific design styles) to the
RD phase.
In this approach, EPA would identify and evaluate
the technologies and provide an analysis of
alternative technologies in the FS (this guidance
and its.associated administrative record will
generally constitute that discussion). The
proposed plan would identify the technologies that
may be finally selected and specify the timing of
and criteria for the future technology selection in
sufficient detail that the public can evaluate and
comment on the proposal. The ROD would also
identify all ARARs and other performance
specifications and information associated with
discharge and treatment of the extracted ground
water, including the types of discharge, effluent
requirements, and specifications developed in
response to community preferences. Specifying
the performance criteria and other requirements in
the ROD (using a type of "performance based
approach") ensures that the remedy will be
protective and meet ARARs. Overall, the ROD
should be drafted so that the final selection of
technologies at the RD phase follows directly
from the application of criteria and judgments
included in the ROD to facts collected during the
RD phase. If the ROD is drafted in this fashion,
documenting the final technology selection can
generally be accomplished by including a
23
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document in the post-ROD portion of the
Administrative Record, which explains the basis
of technology selection (e.g., Basis of Design
Report, or memorandum to the RD file).
Advantages of deferring selection of ex-situ
treatment technologies to the RD include:
• The remedy selection process is further
streamlined, since final selection and the
accompanying detailed analysis for these
technologies is performed only in the RD
not in both the FS and the RD,
minimizing duplication of effort;
• Site information collected during the RD
can be used to make final technology
selections as well as to design the
treatment train, which facilitates selection
of the most cost effective technologies
(see Section 3.4.5);
* The likelihood that changes in the
treatment train will be made during the
RD is explicitly recognized in the ROD;
and
• The time and resources employed in the
FS can focus on other components of the
ground-water remedy that have more
direct influence on attainment of
remedial objectives for contaminated
ground water (see Section 1.0).
Cost estimates for remedial alternatives,
including the ex-situ treatment component, will
need to be included in the FS regardless of
whether or not technology selection is deferred to
the RD. For cost estimating purposes when
deferring technology selection to the RD,
reasonable assumptions should be made
concerning the treatment system, including
assumptions concerning the presumptive
technologies and likely design styles to be used.
To assist in making such assumptions, advantages
and limitations for the presumptive technologies
are summarized in Appendix C4. Also, brief
descriptions of the presumptive technologies and
references for additional information are provided
in Appendix D. Assumptions used for estimating
treatment costs should be consistent across all
remedial alternatives. All assumptions should be
clearly stated as such in the FS and ROD.
Example ROD language for deferring technology
selection to the RD is given in Appendix B3 for a
hypothetical site. This language is only for the ex-
situ treatment portion of an extraction and
treatment remedy and should appear in the
selected remedy portion of the ROD when
following this approach.
3.4 Information Needed for Selecting
Technologies
The site information listed in Highlight 5 is
generally needed to determine the treatment
components of a complete treatment train for
extracted ground water and to select the most
appropriate technology type and design style for
each component. Further detail regarding site data
needed and the purpose of this information is
provided in Appendix C3. Much of this
information is also needed for design of the
extraction component of an extraction and
treatment remedy.
3.4.1 When Should this Information be
Collected? The information listed in Highlight 5
is needed for design of the treatment train.
Therefore, it must be collected prior to or during
the design phase, for either an early action or long-
term remedy. Much of this information should
also be available for selecting among the
presumptive technologies, since it is generally
needed to determine the technologies most
appropriate for site conditions. The timing of
information needed during remedy selection is
different when deferring technology selection to
the RD than when selecting technologies in the
ROD, as discussed in Section 3.3.3. However,
much of this information can be collected along
with similar data gathered during the remedial
investigation (RJ). In general, it is recommended
that as much of this information as possible be
obtained prior to the RD in order to minimize the
24
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Highlight 5. Summary of Site Information
Needed For Treatment Train Design
• Total extraction flow rate
• Discharge options and requirements
• Target effluent concentrations
Contaminants
Degradation products
Treatment additives
Natural constituents
1 • Other requirements
Regulatory
.* . Operational
• Community concerns or
preferences
• Water quality of treatm ent influent
• Contaminant types and
concentrations
• Naturally occurring constituents
• Other water quality parameters
• Treatability information
NOTE: Further detail is provided in Appendix
C3.
need for additional site investigations during the
RD and to accelerate the RD phase.
much of this information can be collected along
with similar data gathered during the remedial
investigation (RI). In general, it is recommended
that as much of this information as possible be
obtained prior to the RD in order to minimize the
need for additional site investigations during the
RD and to accelerate the RD phase.
3.4.2 Extraction Flow Rate. Inflow to the
treatment system is the total flow from all
extraction wells or drains. Estimates of total
extraction flow rate often have a high degree of
uncertainty (i.e., one or more orders of
magnitude), depending on type of data and
estimation method used. Expected flow rates
from extraction wells are typically estimated from
hydraulic properties of the aquifer. Aquifer
hydraulic properties may have considerable
natural variation over the site and accurate
measurement of these properties is often difficult.
In order to reduce uncertainty during design of the
treatment system, aquifer properties used in
estimating the inflow should generally be
obtained from pumping-type aquifer tests and
not from "slug tests," laboratory measurements on
borehole samples or values estimated from the
literature.
Pumping-type aquifer tests provide a much better
estimate of average aquifer properties than other
methods, because a much larger volume of aquifer
is tested. For the same reason, ground water
extracted during pumping tests is more
representative of that which will enter the
treatment system, and should generally be used for
treatability studies of ex-situ treatment
technologies instead of samples obtained from
monitoring wells. Suggested procedures for
conducting pumping-type aquifer tests are given
in EPA, 1993i. Methods for treatment of
contaminated ground water extracted during
pumping-type aquifer tests are discussed in
Section 3.5.
The likely variability in the total extraction rate
during the life of the remedy should also be
estimated. Variability in the extraction rate could
result from addition or removal of extraction
wells, short-term operational changes in the
system (e.g., changing the pumping rates) or
seasonal fluctuations in the water table. The
number of extraction wells could change as a
result of implementing the remedy in phases or
from post-construction refinement of the remedy
(see Section 2.3.1).
25
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3.4.3 Discharge Options and ARARs. All
options for discharge of ground water after
extraction and treatment should be identified and
considered in the FS, especially options that
include re-use or recycling of the extracted ground
water. Water quality requirements for the treated
effluent (i.e., effluent ARARs) may be different
for each discharge option. Examples of regulatory
requirements include those promulgated under the
federal Safe Drinking Water Act and Clean Water
Act, which would apply to discharges to a
drinking water system or to surface waters,
respectively; and state requirements for these
types of discharge. Effluent requirements could
also include those for chemicals added during
treatment, contaminant degradation products, and
naturally occurring constituents (e.g., arsenic), in
addition to those for contaminants of concern. In
general, one or more types of discharge for
extraction and treatment remedies should be
selected in the ROD, not deferred to the RD.
ARARs for the treated effluent will determine the
overall level of treatment needed, which in turn
determines the type of components needed in the
treatment train (see Section 3.3.1) and is a critical
factor in selecting appropriate treatment
technologies.
In some cases it may be appropriate to select more
than one type of discharge for the selected remedy.
One type of discharge may be preferred, but may
not be capable of accepting the entire flow of
treated effluent. For example, it may be possible
to re-use or recycle a portion but not all of the
discharge. It may also be desirable to reinject a
portion of the treated effluent for enhanced
recovery of contaminants (aquifer flushing) but
prohibitively costly to reinject the entire discharge.
In addition to the types of discharge, ARARs
and other specifications related to technology
selection or operating performance of the
treatment system should be specified in the
ROD. Regulatory requirements for all waste
streams from the treatment system should be
specified, including those for the treated effluent;
releases to the air; and those for handling,
treatment and disposal of solid and liquid
treatment residuals. Other specifications could
include those preferred by the affected community,
such as requirements to capture and treat
contaminant vapors (even though not required by
ARARs) or limits on operating noise. Other
specifications may also be needed to maintain
continued operation of the system, such as water
quality conditions necessary to minimize chemical
and/or biological clogging of injection wells or
drains.
3.4.4 Water Quality of Treatment Influent. In
order to design the treatment system, contaminant
types and concentrations and other water quality
parameters must be estimated for the total flow
entering the system. Since some technologies are
more effective than others in removing certain
contaminant types, this is an important technology
selection factor. Concentrations of naturally
occurring constituents as well as background and
site-related contaminants in the extracted ground
water should also be measured, as discussed in
Appendix C3.
3.4.5 Tneatabiliiy Studies. Treatability studies
involve testing one or more technologies in the
laboratory or field to assess their performance on
the actual contaminated media to be treated from a
specific site. These studies may be needed during
the RI/FS to provide qualitative and/or •
quantitative information to aid in selection of the
remedy, or during the RD to aid in design or
implementation of the selected remedy. Three
tiers of testing may be undertaken: 1) laboratory
screening, 2) bench-scale testing, or 3) pilot-scale
testing. Treatability studies may begin with any
tier and may skip tiers that are not needed (EPA,
1989c).
For treatment of extracted ground water,
treatability studies are generally needed to
accurately predict the effectiveness and total cost
of a technology for a given site, including
construction and operating costs; and the costs of
other components that may be needed in the
treatment train (see Section 3.3.1). Optimizing
the cost effectiveness of the treatment train is
especially important for systems designed to
26
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operate over a long time period. (In this guidance,
optimizing the cost effectiveness of the treatment
system is defined as meeting all treatment and
other performance requirements while minimizing
total costs per unit volume of water treated.)
Treatability studies may also indicate that some
technologies provide cost effective treatment when
all of the above factors are considered, even
though these technologies were infrequently
selected in past RODs (e.g., chemical/UV
oxidation or aerobic biological reactors). For
these reasons treatability studies will be helpful in
selecting among the presumptive technologies.
Similarly, a presumptive treatment technology
should not be eliminated from further
consideration in the FS or RD simply because a
treatability study is required to determine its
applicability for a given site. In general, some
type of treatability study should be performed
prior to or during the design of any system
expected to provide long-term treatment of
extracted ground water, including systems using
presumptive technologies.
3.5 Treatment Technologies for Aquifer Tests
Although pumping-type aquifer tests are the
preferred method of determining average aquifer
properties (see Section 3.4.2) and this information
is useful for remedy selection, such testing is often
deferred to the RD phase because of the need to
determine how to treat and/or dispose of the
extracted ground water. To facilitate use of such
tests earlier in the site response, ex-situ treatment
technologies most suitable for this application are
discussed below.
3.5.1 Treatment Needs during Aquifer Tests.
In comparison to an extraction and treatment
remedy, pumping-type aquifer tests (see Section
3.4.2) generate relatively small flows of
contaminated ground water over a short period of
time. At the time of such tests, the estimated
pumping rates and contaminant loadings generally
have a high degree of uncertainty. Often the total
volume of ground water extracted during testing is
held in storage tanks or lined ponds to prevent the
discharge from affecting water levels in
observation wells and interfering with the test.
Storage of the extracted ground water also allows
subsequent flow to a treatment system to be
controlled and optimized. For example, if storage
vessels are used for both the untreated and treated
water, the extracted water can be routed through
the treatment system as many times as necessary
to meet discharge and/or disposal requirements.
Therefore, the cost effectiveness of treatment
technologies (see Section 3.4.5) is less important
for aquifer testing than for the long-term remedy,
because of the much smaller volume of ground
water to be treated and the much shorter period of
operation.
3 JL2 Treatment Technologies for Aquifer
Tests. Technologies for treating ground water
extracted during aquifer tests should be able to
treat a wide range of contaminant types, be
available in off-the-shelf versions (short lead time
for procurement), have a short on-site startup
time, be relatively simple to operate, and be
available in easily transportable units. Of the
presumptive technologies identified above, the
three most suitable for this application are:
• Granular activated carbon,
® Air stripping, and
® Ion exchange/adsorption.
Granular activated carbon can effectively remove
most dissolved organic contaminants and low
concentrations of some inorganic compounds. Ion
exchange/adsorption can remove most metals. Air
stripping may be applicable for volatile organic
contaminants (VOCs) and generally is more cost
effective than granular activated carbon for
treating VOCs when flow rates are greater than
about three gallons per minute (Long, 1993).
Granular activated carbon may still be needed in
conjunction with air stripping, for treating
dissolved semivolatile organic contaminants, or
for reaching stringent effluent requirements for
VOCs. Granular activated carbon may also be
needed for treatment of vapor phase contaminants
separated by an air stripper. Also, treatability
27
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studies generally are not required for the above
three technologies, especially for short-term
applications. Additional information regarding
the availability and field installation of skid or
trailer mounted treatment units (package plants) is
available in EPA, 1995a.
Other presumptive ex-situ treatment technologies
(chemical/UV oxidation, aerobic biological
reactors, chemical precipitation, and
electrochemical methods) generally are less
suitable for aquifer testing purposes. In general,
these other technologies require longer lead times
for procurement and longer time on-site for
startup; and have more complex operating
requirements and higher capital costs.
4.0. REFERENCES
Cohen, R.M., and J.W. Mercer, 1993. DNAPL
Site Evaluation. C.K. Smoley, Boca Raton, FL
and ORD Publication EPA/600/R-93/022.
EPA, 1986. "Guidelines for Ground-Water
Classification Under the EPA Ground-Water
Protection Strategy, Final Draft," November,
1986.
EPA, 1988a. "Guidance for Conducting Remedial
Investigations and Feasibility Studies Under
CERCLA, Interim Final," OSWER Directive
9355.3-01, EPA/540/G-89/004. October 1988.
EPA, 1988b. "Guidance on Remedial Actions for
Contaminated Ground Water at Superfund Sites,"
OSWER Directive 9283.1-2, EPA/540/G-88/003,
December 1988.
EPA, 1989a. "Considerations in Ground Water
Remediation at Superfund Sites," OSWER
Directive 9355.4-03, October 18,1989.
EPA, 1989b. "Interim Final Guidance on
Preparing Superfund Decision Documents,"
OSWER Directive 9335.3-02, October 1989.
EPA, 1989c. "Guide for Conducting Treatability
Studies Under CERCLA, Interim Final,"
OERR/ORD Publication EPA/540/2-89/058,
December 1989.
EPA, 1990a. "ARARs Q's & A's: State Ground-
Water Antidegradation Issues," OSWER
Publication 9234.2-11/FS, July 1990.
EPA, 1990b. "Suggested ROD Language for
Various Ground Water Remediation Options,"
OSWER Directive 9283.1-03, October 10,1990.
EPA, 1991 a. "Guide to Addressing Pre-ROD and
Post-ROD Changes," OSWER Publication
9355.3-02FS-4, Aprill991.
EPA, 19"91 b. "Guide to Developing Superfund
No Action, Interim Action, and Contingency
Remedy RODs," OSWER Publication 9355.3-
02FS-3,Aprill991.
EPA, 199 Ic. "Guide to Principal Threat and Low
Level Threat Wastes," OSWER Publication
9380.3T06FS, November 1991.
EPA, 1992a. "Estimating Potential for
Occurrence of DNAPL at Superfund Sites,"
OSWER Publication. 9355.4-07FS, January
1992.
EPA, 1992b. "Considerations in Ground-Water
Remediation at Superfund Sites and RCRA
Facilities - Update," OSWER Directive 9283.1-
06, May 27, 1992.
EPA, 1992c. "Guidance on Implementation of the
Superfund Accelerated Cleanup Model (SACM)
under CERCLA and the NCP," OSWER Directive
9203.1-03, July 7, 1992.
EPA, 1992d. "The Superfund Accelerated
Cleanup Model (SACM)," OSWER Publication
9203.1-021, November 1992.
EPA. 1992e. "Early Action and Long-Term
Action Under SACM - Interim Guidance,"
OSWER Publication 9203.1-051, December 1992.
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EPA, 1992f. "SACM Regional Decision Teams -
Interim Guidance," OSWER Publication 9203.1-
051, December 1992.
EPA, 1992g. "Evaluation of Ground-Water
Extraction Remedies: Phase n. Volume 1
Summary Report," OSWER Publication 9355.4-
05, February 1992.
EPA, 1992H. "Final Comprehensive State Ground
Water Protection Program Guidance," Publication
EPA 1OO-R-93-001, December 1992.
EPA, 1993a. "Guidance on Conducting Non-
Time-Critical Removal Actions Under CERCLA,"
OSWER Publication 9360.0-32, EPA/540-R-93-
057, August 1993.
EPA, 1993b. "Guidance for Evaluating Technical
Impracticability of Ground-Water Restoration,"
OSWER Directive 9234.2-25. EPA/540-R-93-
080, September 1993.
EPA, 1993c. "Evaluation of the Likelihood of
DNAPL Presence at NPL Sites, National Results,"
OSWER Publication 9355.4-13, EPA/540-R-93-
073, September 1993.
EPA, 1993d. "Presumptive Remedies: Policy and
Procedures," OSWER Directive 9355.0-47FS,
EPA/540-F-93-047, September 1993.
EPA, 1993e. "Presumptive Remedies: Site
Characterization and Technology Selection For
CERCLA Sites With Volatile Organic
Compounds In Soils," OSWER Directive 9355.0-
48FS, EPA/540-F-93-048, September 1993.
EPA, 1993f. "Presumptive Remedy for CERCLA
Municipal Landfill Sites," OSWER Directive
9355.0-49FS, EPA/540-F-93-035, September
1993.
EPA, 1993g. "Innovative Treatment
Technologies: Annual Status Report (Fifth
Edition)", Publication EPA 542-R-93-003,
September 1993.
EPA, 1993h. "In-situ Treatment of Contaminants:
An Inventory of Research and Field
Demonstrations and Strategies for Improving
Ground Water Remediation," OSWER
Publication EPA/500/K-93/001, January 1993.
EPA, 1993i. "Ground Water Issue, Suggested
Operating Procedures for Aquifer Pumping
Tests," OSWER Publication EPA/500/S-93/503,
February 1993.
EPA, 1993J. "Data Quality Objectives Process
for Superfund, Interim Final Guidance" OSWER
Publication 9355.9-01. EPA/540/R-93/071,
September 1993.
EPA, 1994a. "Alternative Methods for Fluid
Delivery and Recovery." ORD/CERI Publication
EPA/625/R-94/003, September 1994.
EPA. 1994b. "DNAPL Site Characterization,"
OSWER Publication 9355.4-16FS, EPA/540/F-
94/049. September 1994.
EPA, 1994c. "RCRA Corrective Action Plan,"
OSWER Directive 9902.3-2A, EPA/520/R-
94/004, May 1994.
EPA. 1994d. "Technical Support Project, Direct
Technical Assistance for Site Remediation,"
OSWER Publication EPA/542-F-94/004. October
^1994.
EPA, 1994e. "Methods for Monitoring Pump-
and-Treat Performance," ORD Publication
EPA/600/R-94-94/123, June 1994.
EPA, 1995a. "Manual: Ground Water and
Leachate Treatment Systems," ORD/CERI
Publication EPA/625 R-94/005, January 1995.
EPA, 1995b. "Consistent Implementation of the
FY 1993 Guidance on Technical Impracticability
of Ground-Water Restoration at Superfund Sites,"
OSWER Directive 9200.4-14, January 19,1995.
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EPA, 1995c. "Superfund Groundwater RODs:
Implementing Change This Fiscal Year," OSWER
Memorandum from Elliott P. Laws to Regional
Administrators and others, July 31,1995 (no
publication number).
EPA, 1995d. "In-Situ Remediation Technology
Status Report: Treatment Walls," OSWER
Publication EPA/542 K-94-004. April 1995.
EPA, 1995e. "Innovative Treatment
Technologies: Annual Status Report (Seventh
Edition)," OSWER Publication EPA-542-R-95-
008 Number 7, Revised, September 1995.
EPA, 1995f. "Soil Vapor Extraction (SVE)
Enhancement Technology Resource Guide,"
OSWER Publication EPA/542-B-95-003,
October 1995.
EPA, 1995g. "Presumptive Remedies for Soils,
Sediments and Sludges at Wood Treater Sites,",
OSWER Directive 9200.5-162. EPA/540-R-
95/128. December 1995.
EPA, 1996a. "Consideration of 'Comprehensive
State Ground Water Protection Programs' by EPA
Remediation Programs." Draft OSWER Directive
9283.1-09 dated June 1996. Final Directive
expected by November 1996.
EPA, 1996b. "Analysis of Remedy Selection
Experience for Ground Water Treatment
Technologies at CERCLA Sites," Draft Final
Report dajed July 1996. Final Report expected by
November 1996.
EPA, 1996c. "Use of Natural Attenuation at
Superfund, RCRA Corrective Action, and
Underground Storage Tank Sites," Draft OSWER
Directive dated September 1996. Final
Directive expected by February 1997.
Federal Register, 1990a. Volume 55, No. 46,
March 8,1990; 40 CFR Pan 300, "National Oil
and Hazardous Substances Pollution Contingency
Plan; Final Rule" (NCP).
Federal Register, 1990b. Volume 55, No. 145,
July 27. 1990; 40 CFR Parts 264, 265, 270 and
271, "Corrective Action for Solid Waste
Management Units at Hazardous Waste Facilities;
Proposed" (proposed Subpart S regulations).
Federal Register, 1996. Volume 61, No. 85, May
1, 1996; "Corrective Action for Releases from
Solid Waste Management Units at Hazardous
Waste Management Facilities, Advance Notice of
Proposed Rulemaking."
Long, G. M., 1993. "Clean up Hydrocarbon
Contamination Effectively," Chemical
Engineering Progress, Vol. 89, No. 5.
National Research Council, 1994. Alternatives
for Ground Water Cleanup. National Academy
Press. Washington, DC.
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APPENDIX A
Additional Background Information
Appendix Al: Background on DNAPL Contamination
Appendix A2: Contaminants Most Frequently Reported in Ground Water at CERCLA
NPL Sites
Appendix A3: Examples of Iii-Situ Treatment Technologies
Appendix A4: Definition and Discussion of Pulsed Pumping
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Appendix Al: Background on DNAPL Contamination
DNAPL Background
A nonaqueous phase liquid (NAPL) is a chemical that is a liquid in its pure form, which does not readily
mix with water but does slowly dissolve in water. Dense NAPLs (DNAPLs) sink while light NAPLs
(LNAPLs) float in water. When present in the subsurface NAPLs slowly release vapor and dissolved phase
contaminants, resulting in a zone of contaminant vapors above the water table and a plume of dissolved
contaminants below the water table. The term NAPL refers to the undissolved liquid phase of a chemical or
mixture of compounds and not to the vapor or dissolved phases. NAPLs may be present in the subsurface as
either "free-phase" or as "residual-phase." The free-phase is that portion of NAPL that can continue to
migrate and which can flow into a well. The residual-phase is that portion trapped in pore spaces by capillary
forces, which can not generally flow into a well or migrate as a separate liquid. Both residual and free-phase
NAPLs are sources of vapors and dissolved contaminants.
LNAPLs tend to pose less of a cleanup problem than DNAPLs. The most common LNAPLs are petroleum
fuels, crude oils and related chemicals, which tend to be associated with facilities that refine, store or
transport these liquids. Since LNAPLs tend to be shallower, are found at the water table and are associated
with certain facilities, they are generally easier to locate and clean up from the subsurface than DNAPLs.
DNAPLs pose much more difficult cleanup problems. These contaminants include chemical compounds and
mixtures with a wide range of chemical properties, including chlorinated solvents, creosote, coal tars, PCBs,
and some pesticides. Some DNAPLs, such as coal tars, are viscous chemical mixtures that move very slowly
in the subsurface. Other DNAPLs, such as some chlorinated solvents, can travel very rapidly in the
subsurface because they are heavier and less viscous than water. A large DNAPL spill not only sinks
vertically downward under gravity, but can spread laterally with increasing depth as it encounters finer
grained layers. These chemicals can also contaminate more than one aquifer by penetrating fractures in the
geologic layer which separates a shallower from a deeper aquifer. Thus, large releases of DNAPLs can
penetrate to great depths and can be very difficult to locate and clean up.
The contamination problem at DNAPL sites has two different components, as shown in Figures Al-1 and
Al-i.the:
• DNAPL zone, and the
• Aqueous contaminant plume.
The DNAPL zone is that portion of the subsurface where immiscible liquids (free-phase or residual DNAPL)
are present either above or below the water table. Also in the DNAPL zone, vapor phase DNAPL
contaminants are present above water table and dissolved phase below water table. The aqueous
contaminant plume is that portion of the contaminated ground water surrounding the DNAPL zone where
aqueous contaminants derived from DNAPLs are dissolved in ground water (or sorbed to aquifer solids) but
immiscible liquids are not present. Depending on the volume of the release and subsurface geology, the
DNAPL zone may extend to great depths and over large lateral distances from the entry location, as discussed
above.
A-1
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Figure A1-1: Components of DNAPL Sites
DNAPL Zone
contains free-phase DNAPL in pools
or lenses and/or; residual DNAPL
DNAPL Entry Location
such as a former waste pond
Aqueous
Contaminant
Plume
Ground-Water Flow
Figure A1-2: Types of Contamination and
Contaminant Zones at DNAPL Sites (Cross-Sectional View)
Limits of DNAPL Zone
DNAPL
Entry
Location
DNAPL
Vapors
Water Table
'• Residual
DNAPL
Aqueous
Contaminant
Plume
Ground-Water Flow
Sand
Free-Phase
DNAPL
After EPA 1992c
A-2
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Appendix A1: Background on DNAPL Contamination (continued)
Planning of site investigation and remedial activities at sites with subsurface DNAPLs should include certain
precautions, to minimize the potential for further DNAPL migration resulting from such activities. Further
detail on characterization of DNAPL sites is provided in EPA, 1994 and in Cohen and Mercer, 1993 (see
below).
DNAPL References
Additional information concerning DNAPL contamination can be obtained from the following references:
Cohen, R.M.. and J.W. Mercer, 1993. DNAPL Site Evaluation. C.K. Smoley, Boca Raton. FL, 1993; and
EPA/600/R-93/022, February 1993.
EPA, 1991. "Ground Water Issue: Dense Nonaqueous Phase Liquids," OS WER Publication EPA/540/4-91 -
002, March 1991.
EPA, 1992a. "Estimating Potential for Occurrence of DNAPL at Superfund Sites," OS WER Publication
9355.4-07FS, January 1992.
EPA, 1992b. "Dense Nonaqueous Phase Liquids -- A Workshop Summary, Dallas, Texas, April 16-18,
1991," Office of Research and Development Publication EPA/600/R-92/030, February 1992.
EPA, 1992c. "Considerations in Ground-Water Remediation at Sujierfund Sites and RCRA Facilities -
Update," OS WER Directive 9283.1 -06, May 27. 1992.
EPA. 1993b. "Guidance for Evaluating Technical Impracticability of Ground-Water Restoration," OS WER
Directive 9234.2-25. EPA/540-R-93-080, September 1993.
EPA. 1994. "DNAPL Site Characterization," OSWER Publication 9355.4-16FS, EPA/540/F-94/049,
September 1994.
A-3
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Appendix A2: Contaminants Most Frequently Reported in Ground Water at CERCLA NPL Sites'
Organic Contaminants:
Rank
I
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Organic Contaminants (Other Names)
Trichloroethylene, 1,1,2- (TCE)a
Tetrachloroethene (perchloroethene; PCE)0
Chloroform (trichloromethane)™
Benzene1*
Toluene"
Trichloroethanc. 1.1,1- (methyl chloroform;
1,1.1-TCAr
Polychlorinated biphenyls
Trans-Dichloroethylene. 1.2- (trans- 1.2-DCEr
Dichloroethane. I.I- (1,1-DCA)"
Dichlorocthene. 1.1- ( vinylidenc chloride; 1 . 1 -DCE)"
Vinyl chloride (chloroethylene)"
Xylene*
Ethylbenzene1*
Carbon tetrachloride (tetrachloromethane)0
Phenol
Methylene chloride (dichloromethane)"
Dichloroethane. 1.2- (ethylcne dichloride; 1,2-DCA)"
Pentachlorophenol (PCP)
Chlorobenzene (benzene chloride)0
Benzo(A)Pyrene
Chemical*
Group
Volatile
Volatile
Volatile
Volatile
Volatile
Volatile
PCB
Volatile
Volatile '.
Volatile
Volatile
Volatile
Volatile
Volatile
Semivol.
Volatile
Volatile
Semivol.
Volatile
Semivol.
Halo-1
genated?
Yes
Yes
Yes
No
No
Yes
Yes
Yes
Yes
Yes
Yes
No
No
Yes
No
Yes
Yes
Yes
Yes
No
DNAPL?3
Yes
Yes
Yes
No
No
Yes
Yes
Yes
Yes
Yes
No
No
No
Yes
No
Yes
Yes
Yes
Yes
Yes
No.1
Sites
336
170
167
164
159
155
139
107
105
95
82
76
68
68
61
58
57
53
48
37
A-4
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Appendix A2: Contaminants Most Frequently Reported in Ground Water at CERCLA NPL Sites
(continued)1
Inorganic Contaminants;
No.1
Rank Inorganic Contaminants Sites
1 Lead 307
2 Chromium and compounds 215
3 Arsenic 147
4 Cadmium 127
5 Mercury4 81
6 Copper and compounds 79
7 Zinc and compounds 73
8 Nickel and compounds 44
9 Cyanides (soluble salts) 39
10 Barium 37
NOTES:
Number of CERCLA National Priorities List (NPL) sites for which the chemical was reported in ground water as
a contaminant of concern in the Superfund Site Assessment, for either proposed or final NPL sites. This data was
obtained from the Superfund NPL Assessment Program (SNAP) data base, as of August 30. 1994. At that time
total of 1 294 sites were listed on the NPL (64 proposed and 1 230 final).
Classification of organic contaminants as volatile, semivolatile. PCB, or pesticide; and as halogenated or
nonhalogcnated is from EPA Publication. 'Technology Screening Guide for Treatment of CERCLA Soils and
• Sludges." EPA/540/2-88/004. September 1988.
Classification of whether or not a chemical is a dense nonaqueous phase liquid (DNAPL) in pure form is from
Cohen and Mercer, 1993 (see References).
In pure form mercury is also a DNAPL.
These organic contaminants arc chlorinated solvents. A total of 1 2 are listed.
These organic contaminants are constituents of petroleum fuels. A total of four are listed.
A-5
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Appendix A3: Examples of In-Sitm Treatment Technologies'
I. Enhanced Recovery Methods
Recirculation/flooding:
Water flooding
(physical)
Steam flooding
(physical)
Chemical flooding2
(chemical)
Nutrient flooding2
(biological)
Thermal enhanced recovery:
Radio frequency
Electrical resistance
(AC or DC)
Enhancement of secondary permeability:
l
Induced fracturing with water or
or air pressure (physical)
Other methods:
Electromigration (electrical)
Treatment Agents
(and process type)
- Water
- Heated water
- Steam
Surfactants
Solvents
Redox agents
Nitrate
Other
-Heat
-Heat
Not applicable
Agent Delivery Methods
- Injection wells
- Injection wells
- Injection wells
- Injection wells
- Injection wells
- Injection wells
- Injection wells
Electrodes in wells
Electrodes in wells
Not applicable
- Electric current
- Electrodes in wells
NOTES:
1 List of technologies and technology status is from EPA. 1993h (see References section of guidance).
2 Chemicals or nutrients for micro-organisms, respectively, are added to reinjection water.
A-6
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Appendix A3: Examples of In-Situ Treatment Technologies (continued)1
II. In-situ Treatment Processes
Physical/chemical treatment:
Volatilization and oxygen
enhancement by air sparging
Reductive dehalogenation by
metal catalysts (abiotic)
Biological treatment:
Oxygen enhancement of aerobic
organisms (also includes air
sparging, above)
Nutrient enhancement of aerobic
organisms
Nutrient enhancement of anaerobic
organisms to produce enzymes that
degrade contaminants (cometabolism)
Sequential anaerobic-aerobic
treatment
Treatment Agents
- Air
- Iron filings
- Other agents
Hydrogen peroxide
Oxygen/surfactant
(microbubbles)
Nitrate
Other
Methane
Other :
Methane and/or
Oxygen
Agent Delivery Methods
- Injection wells
- Permeable walls/gates3
- Permeable walls/gates3
- Injection wells4
- Injection wells4
- Injection wells3
- Injection wells
- Injection wells
NOTES:
In permeable treatment walls/gates, treatment agents are added with trench backfill materials or are injected via
perforated pipes placed in the backfill. These walls are placed in the subsurface across the natural flow path of
the contaminant plume. They can be combined with impermeable flow barriers in a "funnel and gate"
arrangement, in which flow is directed through the treatment walls/gates.
Use of permeable treatment walls/gates to deliver treatment agents for these methods may also be feasible.
A-7
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Appendix A4: Definition and Discussion of Pulsed Pumping
Pulsed Pumping
In pulsed pumping, some or all extraction pumps are turned off and then back on for specified periods of time
(e.g., one or more monitoring periods). The on and off cycles can be continued or the extraction and
treatment remedy can be returned to continuous pumping. Although not widely used in remedies to date, this
method may be effective in enhancing the recovery of contaminants from the aquifer. Pulsed pumping
can recover contaminants located in the following portions of the aquifer that are relatively unaffected during
pumping:
• Upper portions of the aquifer that have been dewatered by pumping, and
• Zones with minimal ground-water flow during pumping (flow stagnation zones).
Pulsed pumping may also enhance contaminant recovery for aqueous phase contaminants that are sorbed to
the aquifer matrix. Therefore, pulsed pumping can be initiated as a post-construction refinement of an
extraction and treatment remedy (see Section 2.4), when an evaluation of remedy performance indicates that
this technique may increase the recovery of contaminants from the aquifer.
Pulsed pumping can also be used as a method of evaluating the effectiveness of an extraction and
treatment remedy and/or the effectiveness of source control actions. For example, if contaminant levels
increase substantially when pumping is stopped, it is an indication that contaminants continue to be derived
from source materials, and that additional remedial measures (e.g., source control/removal) may be necessary.
These source materials could include aqueous contaminants sorbed to aquifer solids in finer-grained aquifer
layers, NAPLs (refer to Appendix A1), contaminated soils, or other sources.
Pulsed pumping should generally not be initiated until after sufficient monitoring data has been obtained
from continuous pumping to establish a statistically valid performance trend. Also, the influence of pulsed
pumping on plume containment should be considered; and extraction wells used primarily for containment
(i.e. at plume leading edge) should generally not be pulsed.
A-8
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APPENDIX B
ROD Language Examples For Selected Remedy
Appendix B1: Phased Implementation of Ground-Water Remedy
Appendix B2: Phased Implementation of Extraction Component of Remedy at a
DNAPLSite
Appendix B3: Deferring Selection of Treatment Components to Remedial Design
Appendix B4: Suggested ROD Language from 1990 OSWER Directive
-------
Appendix Bl: Phased Implementation of Ground-Water Remedy
gite Conditions;
At hypothetical Site 1 (an LNAPL site) surficial soils and the underlying ground water in Aquifer C are
contaminated with volatile organic compounds (VOCs). At this site. Aquifer C is currently used as a source
of drinking water, with several wells located on-site and in the estimated path of the contaminant plume.
Early actions were used for exposure prevention and source control. Under Superfund removal authority,
an alternate water supply was provided to several residences, and leaking drums and heavily contaminated
soils were excavated and taken off-site for disposal. A soil vapor extraction system was installed as an
interim remedial action. No further source control actions are planned. DNAPLs are not likely to be
present in the subsurface because most of the contaminants are LNAPLs rather than DNAPLs in pure form.
The selected ground-water remedy relies on extraction and treatment for preventing further migration of the
contaminant plume and for restoration of Aquifer C. The selected remedy will be implemented in two
construction phases.
ROD Language for Extraction Component of Remedy;
The following, or similar language, should appear in the Selected Remedy section of the ROD:
The ultimate goal for the ground-water portion of this remedial action is to restore Aquifer C to
its beneficial uses. At this site. Aquifer C is currently used as a source of drinking water. Based
on information obtained during the remedial investigation and on a careful analysis of all
remedial alternatives, EPA and the State of believe that the selected remedy will achieve this
goal.
The extraction portion of the ground-water remedy will be implemented in two phases. In phase
one, a sufficient number of extraction wells will be installed with the objective of minimizing
further migration of the contaminant plume. It is currently estimated that two to four extraction
wells will be required for phase one.1 After construction of phase one is completed, the extraction
system will be carefully monitored on a regular basis and its performance evaluated. Operation
and monitoring of phase one for a period of up to one year may be needed to provide sufficient
information to complete the design of phase two.
In phase two, additional extraction wells will be installed with the objective of restoring Aquifer
Cfor use as a source of drinking water, in addition to maintaining the remedial objectives for
• phase one. Restoration is defined as attainment of required cleanup levels in the aquifer, over the
entire contaminant plume. Cleanup levels for each ground-water contaminant of concern are
specified in Table of the ROD. Current estimates indicate that an additional two to four
extraction wells may be required to attain these cleanup levels within a timeframe of
approximately 20 years.' However, monitoring and evaluation of the performance of phase one
will be used to determine the actual number and placement of wells for phase two.
B-l
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Appendix B1: Phased Implementation of Ground-Water Remedy (continued)
The selected remedy will include ground-water extraction for an estimated period of 20 years,
during which the system's performance will be carefully monitored, in accordance with the
monitoring plan defined in Section of the ROD, and adjusted as warranted by the
performance data collected during operation. Refinement of the extraction system may be
required, if EPA determines that such measures will be necessary in order to restore Aquifer C in
a reasonable timeframe. or to significantly reduce the timeframe or long-term cost of attaining
this objective. Refinement of the extraction system may include any or all of the following:
J) Adjusting the rate of extraction from some or all wells;
2) Discontinuing pumping at individual wells where cleanup goals have been
attained;
3) Pulsed pumping of some or all extraction wells to eliminate flow stagnation
areas, allow sorbed contaminants to partition into ground water, or otherwise
facilitate recovery of contaminants from the aquifer; and
4) Installing up to fwo additional ground-water extraction wells to facilitate or
accelerate cleanup of the contaminant plume.1
It is possible that performance evaluations of the ground-water extraction system - after
completion of phase one, during implementation or operation of phase two, or after subsequent
refinement measures - will indicate that restoration of Aquifer C is technically impracticable
from an engineering perspective. If such a determination is made by EPA, the ultimate
remediation goal and/or the selected remedy may be reevaluated.2
NOTES:
1. Although not required in a ROD, the estimated number of wells is included in this example for the
following reasons, to:
• Provide a basis for estimating the cost of the selected remedy, including upper
and lower costs for phase one, phase two and the potential refinement measures;
• Provide some specificity regarding how the extraction component of the
remedy will be used in the overall remediation strategy, because changes in the
extraction system directly influence the time period required to attain the remedial
objectives for this site; and to
o Provide some bounds for the scope, performance and cost of the selected
remedy, which will assist in determining whether future, post-ROD remedy
modifications require an Explanation of Significant Differences (see Section 2.4 of
this guidance). / • • • /
2. Reevaluation of the ultimate remediation goal and/or the selected remedy would generally require an
ESD or ROD amendment.
B-2
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Appendix B2: Phased Implementation of Extraction Component of Remedy at a DNAPL Site
At hypotnet'ca' Site 2 (a DNAPL site), ground water in Aquifer A is contaminated with volatile and
semivolatile organic contaminants (no metals as contaminants of concern). DNAPLs have also been
observed in this aquifer. At this site. Aquifer A is not currently used as source of drinking water, but several
wells are located off-site in the estimated path of the contaminant plume.
The selected remedy includes extraction and treatment for hydraulic containment of the likely DNAPL-zone
(see Appendix A 1 of this guidance) and for restoration of the aquifer outside the DNAPL-zone. Reinjection
of a portion of the treated ground water will be used to enhance recovery of contaminants from the aquifer.
It has been determined that aquifer restoration within the DNAPL-zone is technically impracticable from an
engineering perspective, as explained in the Statutory Determinations section of the ROD. The remedy
will be implemented in two construction phases.
ROD Language for Extraction Component of Remedy:
The following, or similar language, should appear in the Selected Remedy section of the ROD:
The ultimate goal for the ground-water portion of this remedial action is to restore the maximum
areal extent of Aquifer A to its beneficial uses. At this site Aquifer A is potentially useable as a
source of drinking water and is currently used off-site for this purpose. Based on information
obtained during the remedial investigation and on a careful analysis of all remedial alternatives,
EPA believes that the selected remedy will achieve this goal. '
**
The extraction portion of the ground-water remedy will be implemented in two phases. In phase
one, a sufficient number of extraction wells will be installed to achieve two remedial objectives
for Aquifer A: I) minimizing further migration of contaminants from suspected subsurface
DNAPL areas to the surrounding ground water; and 2) minimizing further migration of the
leading edge of the contaminant plume. It is currently estimated that three to five extraction
wells will be required for phase one.1 After construction of phase one is completed, the
extraction system will be carefully monitored on a regular basis and its performance evaluated.
This evaluation may provide further information concerning the extent of the DNAPL-zone.
Operation and monitoring of phase one for a period of up to two years may be needed to
provide sufficient information to complete the design of phase two.
In phase two. additional extraction wells will be installed with the objective of restoring the
maximum areal extent of Aquifer A for use as a source of drinking water, in addition to
maintaining phase one objectives. Reinjection wells and related pumping equipment for flushing
a portion of the treated ground water through the aquifer (water flooding) will also be installed
in order to enhance the recovery of contaminants. Restoration is defined as attainment of
required cleanup levels in the aquifer, over the portion of the contaminant plume outside the
DNAPL-zone. Cleanup levels for each ground-water contaminant of concern are specified in
Table _ ; although cleanup level ARARs within the DNAPL-zone have been waived by EPA due
technical impracticability from an engineering perspective, as discussed in Section _ of the
ROD. Current estimates indicate that these cleanup levels can be attained in the portion of
Aquifer A outside the DNAPL-zone within a timeframe of approximately 25 years.
B-3
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Appendix B2; Phased Implementation of Extraction Component of Remedy at a DNAPL Site
(continued)
Current estimates also indicate that an additional two to six extraction wells and two to four
reinjection wells may be required for phase two.1 However, monitoring and evaluation of the
performance of phase one will be used to determine the actual number and placement of wells
for phase two.
The selected remedy will include ground-water extraction for an estimated period of 25 years,
during which the system's performance will be carefully monitored, in accordance with the
monitoring plan defined in Section of the ROD, and adjusted as warranted by the
performance data collected during operation. Refinement of the extraction system may be
required, if EPA determines that such measures will be necessary in order to restore the maximum
areal extent of Aquifer A in a reasonable timeframe, or to significantly reduce the timeframe or
long-term cost of attaining this objective. Refinement of the extraction system may include any
or all of the following:
I) Adjusting the rate of extraction from some or all wells;
2) Discontinuing pumping at individual wells where cleanup goals have been
attained;
3) Pulsed pumping of some or all extraction wells to eliminate flow stagnation
areas, allow sorbed contaminants to partition into ground water, or otherwise
facilitate recovery of contaminants frqm the aquifer;
4) Installing up to two additional ground-water extraction wells to facilitate or
accelerate cleanup of the contaminant plume; and
5) Installing up to two additional reinjection wells.
It is possible that performance evaluations of the ground-water extraction system - after
completion of phase one, during implementation or operation of phase two, or after subsequent
refinement measures - will indicate that restoration of portions or all of Aquifer A is technically
impracticable from an engineering perspective. If such a determination is made by EPA, the
ultimate remediation goal and/or the selected remedy may be reevaluated.2
NOTES:
1. The reasons for including the estimated number of wells in this example are discussed in the Notes
section of the previous example. Appendix B2.
2. Reevaluation of the ultimate remediation goal and/or the selected remedy would generally require an
BSD or ROD amendment.
B-4
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Appendix B3: Deferring Selection of Treatment Components to Remedial Design
citA Conditions:
Hypothetical Site 2 is the same site used in the previous example, Appendix B2. Most of the treated
ground water will be discharged to the nearby Muddy River, although a portion (20 to 30 percent) will be
rcinjected to Aquifer A to enhance contaminant recovery. Contaminant-specific and other water quality
requirements for discharge to the Muddy River were specified by the state and are listed in Table of the
ROD. Other specifications for the treatment system are also listed in the ROD, which include filtering of
suspended mineral solids to minimize clogging of reinjection wells; and treatment of vapor phase organic
contaminants from air stripping or other processes, as requested by the local community.
ROD Language for Treatment Component of Remedy;
The ex-situ treatment component of the ground-water remedy will utilize presumptive
technologies identified in Directive 9283.1-12 from EPA's Office of Solid Waste and Emergency
Response (OSWER), included as Attachment __ of the ROD. Since contaminants of concern
include volatile and semivolatile organic compounds, one or more of the presumptive
technologies - air stripping, granular activated carbon (GAC). chemical/UV oxidation and
aerobic biological reactors - will be used for treating aqueous contaminants in the extracted
ground water. Other technologies will also be needed in the treatment system for removal of
suspended mineral solids and treatment of vapor phase contaminants. The actual technologies
and sequence of technologies used for the treatment system will be determined during remedial
design. Final selection of these technologies will be based on additional site information to be
collected during the remedial design. (See Section 3.4 and Appendix C3 of OSWER Directive
9283.1-12 for a discussion of site information needed for'selection and design of the ex-situ
treatment system.) Based on this additional information and sound engineering practice the
treatment system shall be designed to:
* Attain the chemical-specific discharge requirements and other performance
criteria specified in Table __ and Section _ of the ROD; and
* Treat, or be easily modified to treat, the expected flow increase from phase one
to phase two of the extraction system.
Other design factors shall include:
* Maximizing long-term effectiveness,
* Maximizing long-term reliability (i.e., minimize the likelihood of process upsets)
and
• Minimizing long-term operating costs.
Additional information concerning presumptive technologies for the ex-situ treatment component
of the remedy is provided in OSWER Directive 9283.1-12. Descriptions of each of the
presumptive technologies are presented in Appendices Dl through D8, and advantages and
limitations of each of these technologies are listed in Appendix C4 of this directive.
B-5
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Appendix B3: Deferring Selection of Treatment Components to Remedial Design (continued)
For the purpose of estimating the approximate cost of the treatment component of the selected
remedy, the following treatment sequence is assumed for aqueous contaminants: flow
equalization tanks, a gravity oil-water separator, an air stripper, followed by GAC units. GAC
will also be used to treat vapor phase contaminants from the air stripper. The GAC units will be
thermally reactivated at an off-site facility. Separated DNAPL compounds will be recycled if
possible, but since the actual composition of the recovered liquids is unknown, costs for
incineration at an off-site facility were used for the cost estimate.
B-6
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Appendix B4: Suggested ROD Language from 1990 OSWER Directive
Recommended language for the Selected Remedy section of the ROD was given in OSWER Directive
9283.1-03, entitled "Suggested ROD Language for Various Ground-Water Remediation Options," dated
October 10, 1990. For the RODs in which the final remedy without a contingency is selected, this Directive
recommended that "the following type of language should appear in the Selected Remedy section of the
ROD:"
The goal of this remedial action is to restore ground water to its beneficial use. which is. at this
site, (specify whether this is a potential or actual drinking water source, or is used for non-
domestic purposes). Based on information obtained during the remedial investigation and on a
careful analysis of all remedial alternatives, EPA < (optional) and the State/Commonwealth of
> believe that the selected remedy will achieve this goal. It may become apparent, during
implementation or operation of the ground-water extraction system and its modifications, that
contaminant levels have ceased to decline and are remaining constant at levels higher than the
remediation goal over some portion of the contaminated plume. In such a case, the system
performance standards and/or the remedy may be reevaluated.
The selected remedy will include ground-water extraction for an estimated period of.
years, during which the system's performance will be carefully monitored on a regular basis and
adjusted as warranted by the performance data collected during operation. Modifications may
include any or all of the following:
a) at Individual wells where cleanup goals.have been attained, pumping may be
discontinued;
b) alternating pumping at wells to eliminate stagnation points;
c) pulse pumping to allow aquifer equilibration and to allow adsorbed
contaminants to partition into ground water; and
d) installation of additional extraction wells to facilitate or accelerate cleanup of
the contaminant plume.
To ensure that cleanup goals continue to be maintained, the aquifer will be monitored at those
wells where pumping has ceased on an occurrence of every '. years following
discontinuation of ground-water extraction.
B-7
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APPENDIX C
Ex-Situ Treatment Technologies for Ground Water
Appendix C1: Ex-Situ Technologies Considered in Sample of 25 Sites
Appendix C2: Other Components Needed for Treatment Trains
Appendix C3: Information Needed for Selection of Technologies and Design of
Treatment Train
Appendix C4: Advantages and Limitations of Presumptive Treatment Technologies
-------
Appendix Cl: Ex-Situ Technologies Considered in Sample of 25 Sites
Technologies that were considered for treatment of extracted ground in the sample of 25 sites reviewed in
detail (EPA, I996b) are listed below. These technologies were either considered in the feasibility study
(FS), or considered and/or selected in the record of decision (ROD) or remedial design. The technologies are
listed according to overall process type, and by design style within each type. Those technologies identified
as presumptive technologies are also indicated. For further information on how presumptive technologies
were identified, refer to Section 3.2 of this guidance and EPA, 1996b.
For Treatment of Organic Contaminants:
Presumptive Technologies;
Air stripping:
• Packed tower
- Ambient temperature
- Higher temperature
• Aeration methods
- Ambient temperature
- Higher temperature
• Cascade falls
Granular activated carbon (GAC)
Chemical/UV oxidation:
• Chemical oxidation alone
- Ozone
-. Hydrogen peroxide
- Chlorine compounds
- Potassium permanganate
• Chemical with UV oxidation
- Ozone
- Hydrogen peroxide
• UV oxidation alone (photolysis)
• Alkaline chlorination (for cyanide)
• Unspecified oxidation methods
Aerobic biological reactors:
• Attached growth
- Trickling filter
- Rotating biological contactors
- Fixed bed
• Suspended growth
- Activated sludge
- Sequencing batch reactors
- Aeration ponds/lagoons
- Unspecified suspended growth
• Unspecified aerobic reactors
For Treatment of Metals:
Chemical precipitation:
« Hydroxide precipitants
- Sodium hydroxide
- Lime
- With prior chemical reduction
• Sulfide precipitants
- Sulfur dioxide
- Sodium sulfide
- Sodium btsulfide/bisulfites
- With prior chemical reduction
- Unspecified sulfide precipitant
• Other precipitation methods
- Ferrous sulfate
. - Potassium permanganate
•. - Activated consumable element
- Unspecified chemical precipitation
Ion exchange/adsorption:
• Fixed bed
- Impregnated/synthetic resin
- Activated alumina
• Electrodialysis
• Unspecified ion exchange
Electrochemical methods:
• Electrochemical reduction
« Magnetically activated
Aeration of Background Metals:
• Aeration basin
• Cascade aeration
• Other aeration methods
C-I
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Appendix Cl: Ex-Situ Technologies Considered in Sample of 25 Sites (continued)
For Treatment of Organic Contaminants: For Treatment of Metals:
Other Technologies Considered:
Granular activated carbon (for metals)
Chemical treatment:
• Hydrolysis Reverse Osmosis
• Catalytic dehydrochlorination
• Catalytic dechlorination Biological treatment of metals
• Chlorinolysis
Thermal Destruction:
• Incineration
• Calcination
•, Wet air oxidation
• Supercritical water oxidation
• Microwave discharge/plasma
High temperature separation:
• Steam stripping
• Distillation
Membrane filtration:
• Reverse osmosis
• Ultrafiltration
•.
Anaerobic biological treatment:
• Anaerobic biological reactor
• Enzymatic degradation
Liquid-liquid extraction:
• Solvent extraction
• Liquid carbon dioxide extraction
Evaporation:
• Evaporation basin
Land treatment:
• Surface spreading
•. Spray irrigation
C-2
-------
Appendix C2: Other Components Needed for Treatment Trains'
Solid or Liquid Separation
Technologies
• Oil/grease separation4
• Filtration5
• Coagulation5
(or flocculation)
• Clarification5
(or sedimentation)
Effluent Polishing Technologies*
• Activated carbon
• Ion exchange
• Neutralization
Vapor Phase Treatment
Technologies3
Activated carbon
Resin adsorption
Catalytic oxidation
Thermal incineration
Acid gas scrubbing
Condensation
General Sequence of Unit Processes Used in Aqueous Treatment Trains
Sequence Unit Treatment Process Treatment Stage
Begin
End
Equalize inflow
Separate solid particles
Separate oil/grease (NAPLs)
Remove metals
Remove volatile organics
Remove other organics
Polish organics1
Polish metals
Adjust pH, if required
Pretreatment
Pretreatment
Pretreatment
Treatment"
Treatment
Treatment
Post-treatment
Post-treatment
Post-treatment
NOTES:
In addition to the presumptive technologies lilted in the guidance, other treatment componenu are needed either prior to (preneatmeni) or subsequent to
(poll-treatment) the presumptive technolotiea. Thii listing ii not intended to be presumptive. Not listed are technologies thai may be required for treatment
residuals, such u spent carbon.
Effluent polish nj technolofies are thote used for the final stage of treatment prior to discharge, and can include pfi adjustment (neutralization) aa well aa
, additional removal of aqueous cocuotuenu.
Vapor phase conuminanu released durinf wuer treatment may need to be contained and treated. This includes organic contaminants volatilized during air
stripping from biological treatment, or other cues released from chemical oxidation, reduction or biologic processes (e.g., hydrochloric acid, hydrogen
sulfidc. methane, etc.).
Method! for septotion of oil and/or jrcaae from water include, but are not limited to. gravity separation and dissolved air floatation. These methods can be
used to remove NAPLa from the extracted Ground water.
These lechnolopei can be used to remove solid particle! at the bepnnin j of the treatment train or for removal of other solids resulting from chemical
precipitation, chemical/I! V oxidation or biological treatment
C-3
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Appendix C3: Information Needed for Selection of Technologies and Design of Treatment Train
Information Needed Purpose of Information
1. Total extraction flow rate:
• Total extracted flow
• Flow variability
• Uncertainty of estimate
Inflow to the treatment system is the total flow from
all extraction wells. Since this flow must also be
discharged, large flows may determine the availability
of some discharge options. Flow rate and
concentration determines the mass loading (mass per
unit water volume) of each contaminant entering the
treatment system. The mass loading determines the
dimensions and capacities of treatment vessels, and
whether continuous flow or batch design are used for
each treatment unit. Flow is also a factor for selecting
among the presumptive treatment technologies
because some are less cost effective for high or low
flows.
Variable inflow rates may require use of flow
equalization tanks, batch instead of continuous flow
operation or use of modular treatment units that can
be added or subtracted from the treatment train. Some
technologies can handle variable flow more easily
than others. Variable extraction rates may result from
short-term operational changes, seasonal changes or
phased well installation.
Uncertainty in the flow estimate can result from
natural variability of aquifer properties over the site,
and from the method used to measure these properties.
Since flow is a critical design parameter, additional
characterization may be needed to reduce the level of
uncertainty. Estimates of the total extraction rate
should be based on pumping type aquifer tests,
since this method provides a much better estimate
of average aquifer properties than other methods.
C-4
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Appendix C3: Information Needed for Selection of Technologies and Design of Treatment Train
(continued)
Information Needed
2. Discharge options and effluent requirements:
• Options available
• Target effluent concentrations, each
option
- Contaminants
- Contaminant degradation
products
- Treatment additives
- Natural constituents
- Water quality parameters
• Other requirements, each option
- Regulatory
- Operational
• Community concerns or preferences
Purpose of Information
Options for discharge of treated ground water could
include: discharge to surface waters; discharge to a
drinking water system; reuse or recycling for other
purposes (e.g., industrial processes); infiltration or
reinjection to shallow subsurface or reinjection to the
same aquifer; or discharge to POTW. Target effluent
concentration levels for both contaminants and
naturally occurring constituents may be markedly
different for each discharge option.
Effluent requirements could include those for
chemicals added during treatment, contaminant
degradation products, naturally occurring constituents
(e.g.. arsenic), and water quality parameters (e.g..
suspended solids) in addition to maximum
concentration levels for chemicals of concern. These
requirements will determine the overall level of
treatment needed, which in turn determines the type of
components needed in the treatment train and is a
critical factor in selecting appropriate treatment
technologies.
Each discharge option may have different water
quality requirements for the treated effluent, from both
a regulatory and operational standpoint For
example, reinjection to the subsurface must meet
substantive federal and/or state requirements for
underground injection (regulatory) as well as
minimize chemical and biological clogging of
injection wells or infiltration lines (operational). Use
of the best available technology (BAT) could also be a
regulatory requirement. The affected community
may also have concerns or preferences regarding the
type of discharge.
Target effluent concentrations determine the overall
removal efficiency the treatment train must attain for
each constituent. For example, if the target effluent
level is 10 mg/L and the inflow concentration is 1000
mg/L, then the treatment train must attain an overall
removal efficiency of 99.0 percent (1000 - 0.99(1000)
= 10). The treatment train may need to include more
than one type of technology, or multiple units of a
single technology, in order to attain the required
overall removal efficiency.
C-5
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Appendix C3: Information Needed for Selection of Technologies and Design of Treatment Train
(continued)
Information Needed
3. Water quality of treatment influent:
• Contaminant types and concentrations:
- Inorganic chemicals
- Organic chemicals
- Concentration changes over time
- Nonaqueous phase liquids
(NAPLs)
• Naturally occurring constituents:
- Major cations (metals) and
anions
- Organic chemicals
- Radionuclides
Purpose of Information
Contaminant types and concentrations must be
estimated for the total flow entering the treatment
system. Since some technologies are more effective in
removing certain contaminant types, this is an
important technology selection factor. Inflow
concentrations are needed to determine the removal
efficiency of the treatment train, as discussed above.
The design should consider the potential for inflow
concentrations to change over time. Contaminant
concentrations usually decrease as remediation
progresses. Also, short term increases may occur if a
"hot spot" of more highly contaminated ground water
is captured by the extraction system. Samples
obtained from pumping type aquifer tests provide
better estimates of average contaminant
concentrations, because such samples are obtained
from a relatively large aquifer volume.
If present, subsurface NAPLs (refer to Appendix Al)
may become entrained in the extracted ground water.
These immiscible liquids should be removed in a
pretreatment step (process used prior to other
treatment methods). Also, a specialized extraction
system may be needed to remove free-phase NAPLs
from the subsurface.
Naturally occurring or non-site related constituents
may need to be removed to prevent interference with
treatment processes and may be a factor in technology
selection. Metals such as iron, manganese, and
calcium can leave mineral deposits (scaling) on air
stripper packing and on activated carbon or other
treatment media. If not accounted for, these metals
can also cause premature exhaustion of ion exchange
capacity and increased consumption of reagents in
chemical oxidation or precipitation processes. Iron
also promotes biological fouling in air strippers.
Heavy metals (e.g., lead, mercury) and cyanides can
be toxic to microorganisms in biological reactors.
Metals can also form deposits on well screens of
extraction or reinjection wells (encrustation) or
promote biological fouling (clogging) on well screens.
C-6
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Appendix C3: Information Needed for Selection of Technologies and Design of Treatment Train
(continued)
Information Needed
3. Water quality of influent (continued):
• Other water quality parameters:
- Indicator parameters
- Design parameters
Purpose of Information
Dissolved organic constituents (e.g., from decay of
organic materials or from landfill leachate) can
interfere with adsorption of targeted compounds and
can cause premature exhaustion of activated carbon.
Metal-organic complexes can interfere with chemical
oxidation or precipitation processes.
If present, naturally occurring radionuclides can
accumulate in treatment media or residuals (e.g.,
activated carbon or chemical sludges) resulting in
potential exposure hazards for personnel and
additional transportation and disposal considerations.
Other water quality parameters are used as effluent
quality standards, indicator parameters, or design
parameters for treatment processes. Indicator
parameters are used to indicate the presence of other
constituents. For example, total dissolved carbon
(TDC) is a measure of the relative level of dissolved
organic constituents. Gross alpha and gross beta
particle activity are relatively simple measurements
that indicate the relative abundance of naturally
occurring radionuclides. Other indicator parameters
include: total dissolved solids (TDS), chemical
oxygen demand (COD), biological oxygen demand
(BOD) and total suspended solids (TSS).
Temperature and pH are design parameters for most
treatment processes.
Also, high levels of total suspended solids (TSS) in
extracted ground water may indicate that extraction
wells are not properly designed or developed. Most
treatment technologies require that suspended solids
in excess of certain level be removed during
pretreatment, where acceptable levels may differ for
each technology.
C-7
-------
Appendix C3: Information Needed for Selection of Technologies and Design of Treatment Train
(continued)
Information Needed
Purpose of Information
4. Treatability information:
• From technical literature
• Treatability studies
- Laboratory screening
- Bench-scale testing
- Pilot-scale testing
• Modeling predictions
•Projections of effluent quality
Treatability information is needed to select technology
types and design styles from among the presumptive
technologies; and for selection and design of other
components of the treatment train. The particular mix of
contaminants and naturally occurring constituents can
vary considerably for different sites. Treatability
information is available in the technical literature for
some technologies, including air stripping and granular
activated carbon (GAC).
TreatabHity studies include 1) laboratory screening. 2)
bench-scale testing, or 3) pilot-scale testing. These
studies may begin with any tier and skip tiers that are not
needed (see Section 3.4 of guidance). Computer models
for predicting treatment performance are available for
some technologies.
In general, treatability studies should be performed prior
or during the design of any system expected to provide
long-term treatment of extracted ground water.
including systems using presumptive technologies.
Treatability studies are needed to accurately predict the
effectiveness and cost of a technology for a given site,
including construction and operating costs; and the costs
of other components of the treatment train. Optimizing
the cost effectiveness of the treatment train (i.e..
minimizing the total cost per unit volume of water
treated) is especially important for systems designed to
operate over a long time period.
Treatability studies may reveal unexpected site
conditions, such as the presence of naturally occurring
compounds that interfere with the planned treatment
process or that metal contaminants can be effectively
removed by removing mineral solids. Such studies are
also needed to determine pretreatment requirements, and
requirements for treating aqueous, vapor and solid waste
streams resulting from a particular treatment process.
Treatability studies are needed to determine optimum
chemical reagents and reagent quantities for pH
adjustment; oxidation, reduction or precipitation of
contaminants; and parameters for design of biological
and other reactors.
Treatability studies should be performed on samples
obtained from pumping type aquifer tests instead of
from monitoring wells, because such samples are more
representative of contaminated ground water that will
enter the treatment system. Samples obtained for
treatability studies should be obtained after several hours
of pumping.
C-8
-------
Appendix C4: Advantages and Limitations of Presumptive Treatment Technologies
Technology
Advantages
Limitations
Treatment Technologies for the Removal of Organic Contaminants
Air Stripping • Successfully used in hundreds of ground water
applications
• Low operating cost relative to other technologies
(e.g., energy usage is relatively low).
• Operationally simple system requiring a minimum of
operator assistance.
• Trealability studies often not required for selection or
design, but are recommended.
• Trained contractors available to implement the
technology.
Contaminants transferred to air, and treatment of air emissions may be required.
Pretreatmcm for metals removal and pH control may be needed to reduce fouling and
corrosion.
Post-treatment (polishing) may be required.
Large surges in influent concentrations can reduce removal efficiency because the efficiency
for an individual compound is fixed regardless of influent concentrations.
Air stripping is not as effective for compounds with low Henry's law constants or high
solubilities.**
Cold weather can reduce efficiency.
n
CD
Granular
Activated
Carbon
Successfully used for contaminated ground water at
many Superfund and underground storage tank sites.
Operationally simple system requiring a minimum of
operator assistance.
Regularly used as a polishing step following other
treatment technologies.
Trealability studies generally, not required, but are
recommended (information is available from carbon
vendors).
Trained contractors available to implement the
technology.
Generally a cost-effective alternative as single- step
treatment for flows less than about 3 gpm.*
Activated carbon is generally too costly for use as a single-step treatment if ground-water
chemistry requires high carbon usage rates.
Contaminants are not destroyed but are transferred to another media (i.e., spent carbon must
be regenerated or disposed of properly).
Pretreatment for suspended solids removal is often required.
Pretreatmcm for metals removal and pH control may be needed to reduce fouling and
corrosion.
Organic compounds that have low molecular weight and high polarity are not recommended
for activated carbon (e.g., acetone).
Naturally occurring organic compounds may exhaust carbon bed rapidly and may interfere
with the adsorption of targeted chemicals.
-------
Appendix C4: Advantages and Limitations of Presumptive Treatment Technologies (continued)
Technology
Advantages
Limitations
Chemical/ UV • Where oxidation is complete, organic contaminants
Oxidation are destroyed and not transferred to other media;
minimal residuals generated.
« Effective on a wide variety of volatile and
semivolatile organics, including chlorinated
organics, as well as cyanide and some meials.
' Operating costs can be competitive with air stripping
and activated carbon.
Incomplete oxidation will leave original contaminants and possibly toxic oxidation products;
activated carbon polishing may be required.
Capital costs may preclude small-scale applications, especially for ozone systems.
Metals may precipitate during oxidation, requiring filtration post-treatment and residuals
disposal.
UV light sources are subject to fouling and scaling from solids, iron compounds, carbonates,
etc. Pretreatment may be required to remove these substances.
Process must be closely monitored to ensure contaminant destruction and to prevent safely
hazards.
Peroxide and other chemical oxidants must be properly stored and handled.
Site-specific instability studies are necessary (process may require large quantities of oxidizer
to destroy target compotmd(s) if reactive nontarget compounds are present).
n
o
Aerobic * Organic contaminants degraded, often with minimal
Biological cross-media environmental impacts.
Reactors • Proven effective for many organic compounds.
« Some systems (e.g., trickling filters and rotating
biological contactors) have minimal energy
requirements and generally low capital and operating
costs.
• Can be designed .to require a minimum of operator
attention.
• Relatively simple, readily available equipment.
• Trained contractors available to implement the
technology.
• A residual organic sludge is generated that must be disposed of properly.
• Some compounds are difficult or impossible to degrade (recalcitrant) or slow to degrade.
« Difficulties acclimating microorganisms to contaminants are possible; requires longer startup
time than other technologies to achieve effective steady-state performance
« Volatile organics may require air emission controls or pretreatment to remove them.
* Variations in flow or concentration may require significant operator attention to prevent
microorganisms from being killed.
• Cold weather can cause operational difficulties.
» Treatability studies are needed for selection and design.
• Pretreatment may he needed to remove contaminants toxic to the microorganisms, such as
heavy metals.
» Low organic loading and the potential for supplementary nutrients and food sources must be
considered. - ,
-------
Appendix C4: Advantages and Limitations of Presumptive Treatment Technologies (continued)
Technology
Advantages
Limitations
Treatment Technologies for the Removal of Inorganic Contaminants
Chemical
Precipitation
n
• Most commonly used method
for removing soluble heavy
metal ions from contaminated
water.
• Pretreatment for solids and iron
generally not required.
Hydroxide Precipitation
• Reliable method, chemicals
relatively easy to handle, and not
costly.
Carbonate Precipitation
• Reliable method, calcium
carbonate easy to handle, and
not costly.
• Effectively removes a variety of
soluble metals.
Sulfide Precipitation
• Reliable method.
• High removal efficiency over a t.
broader pH range.
« Relatively insensitive to most
chelating agents.
• Can remove chromates and
dichromates without reducing
hcxavalcm chromium to
trivalent form if ferrous ions are
present or added.
• A residual sludge is generated that must be treated and/or disposed of properly; metals are
not usually easy to recover from sludge.
• Up to four times stoichiomctric chemical additions may be required, especially for sulfide
precipitation (see below).
Hydroxide Precipitation
• Organics or complexing ions may form chelates/complexes instead of insoluble metal
hydroxides.
• Optimum pH is different for each metal hydroxide, one pH may not effectively treat all
soluble metal ions; successive treatments may be required.
• pH must be controlled within a narrow range.
• Naturally occurring sulfate in ground water may react with lime to form gypsum, which
increases sludge, can clog filters, and can coat pipelines (caustic soda addition can reduce
this problem but increases costs and dissolved solids [sodium salts] that must be removed
from treated ground water).
Carbonate Precipilaliorj
• Calcium carbonate is not effective for ground water with high alkaline content.
• Pretreatment to remove organic, chelating, or oil and grease contaminants may be required
Sulfide Precipitation (Soluble Sulfide^
. • Excess sulfide ions that are not precipitated remain in solution. They may be removed by
using aeration to convert them from ionic to oxide form (sulfate).
• pH control between 8 and 9.5 is required to avoid release of hydrogen sulfide gas.
* Cost is high compared to hydroxide and carbonate precipitation
Suifide Precipitation (Insoluble Sulfides)
• Ferrous sulfide is used in amounts greater than that required by stoichiometric
considerations.
« Produces more sludge than soluble sulfide or hydroxide processes.
-------
Appendix C4: Advantages and Limitations of Presumptive Treatment Technologies (continued)
Technology
Advantages
Limitations
Treatment Technologies for the Removal of Inorganic Contaminants (continued):
10(1 EX^ ' Highrem°Val emdenCi"f0r ' ?™ «,««"y -"V and may no, be Cost-effective for ,arge ,rea,me^~
• Generates large volume of backftush solution (approximately 2.5 to 5% of the oriui'nal
ground-water flow rate! ihai is rnnrvnirai.H ;„ .I.. ~-._i j .
Adsorption
Electro-
chemical Methods
High removal efficiencies for
heavy metals.
Suitable for use as a polishing
step after other technologies.
Technology is reasonably well
understood.
On-site backflushing of
exchange media allows
immediate reuse.
.
s in themctals removed and r«l"i
Requires bench-scale testing to determine operational requirements and suitability of
prospective resins. '
Beds can be fouled by paniculate matter, oxidizing agents, oils, greases, biological growths
and imra-bedprec.pltates; therefore, prctreatmem may be needed
Resms may be irreversibly harmed by aromatics and certain other organic compounds; and
anganCSe' C°PPCr ^Cn°Ugh diSS°1VCd °Xygen i$ Presem- ******
High removal efficiencies for
certain heavy metals.
Can treat both metals and
cyanide simultaneously.
Technology is reasonably well
understood.
Requires little floor space due to
short residence lime for
hexavalent chromium reduction.
Requires minimal operator
attention.
Low operating costs compared
to chemical reduction or
precipitation.
Requires no chemical addition.
Paniculate matter, oxidizing agents, oils, greases, biological growths may reduce process
efficiency; therefore, prctrcatmenl may be needed.
Hexavalem chromium reduction generates a heavy metal precipitate that must be removed
from solution in a subsequent clarification or settling process
A heavy metal sludge residual may be generated that may require treatment (dewatering
and/or fixation) and that will require disposal.
A Jpent acid rinse solution may be generated that requires treatment or disposal
Electrodes must be replaced occasionally. '
NOTES:
' U.S. Environmental Protection Agency. 1991. Engineering Bulletin: Air Shipping of Aqueous Solutions. EPA/540/2-91/022. 8pp.
B.Lamarre. 1993. Selecting an air stripper (what to consider!) The National Environmental Journal: 26-29.
G.M.Long. 1993. Clean up hydrocarbon contamination effectively. Chemical Engineering Progress: 58-66.
-------
-------
APPENDIX D
Descriptions of Presumptive Treatment Technologies
Appendix D1:
Appendix D2:
Appendix D3:
Appendix D4:
Appendix DS:
Appendix D6:
Appendix D7:
Appendix D8:
Air Stripping
Granular Activated Carton
Chemical/UV Oxidation
Aerobic Biological Reactors
Chemical Precipitation
Ion Exchange/Adsorption
Electrochemical Methods
Aeration of Background Metals
-------
Appendix Dl: Air Stripping
Air stripping uses volatilization to transfer contaminants from ground water to air. In general, water is
contacted with an air stream to volatilize dissolved contaminants into the air stream. Stripping of a specific
chemical depends on the equilibrium vapor pressure of that chemical as expressed by its Henry's law
constant.
Applicability
Air stripping is applicable to most of the volatile organic compounds (VOCs) as well as volatile inorganics
such as ammonia and hydrogen sulfkte. VOCs with high solubility in water (e.g., acetone) are more difficult
to air strip. Air stripping is potentially applicable to certain halogenated semi-volatile organic compounds
(SVOCs). It is not applicable to nonhalogenated SVOCs; heavy organics such as PCBs, dioxins/furans
and pesticides; or inorganic metal compounds (U.S. EPA, 1991).
Air stripping is most effective for contaminants with a dimensionless (molar volume) Henry's law constant
greater than 0.01 (or 2.4 x 10"* atm-m3/gmol at 25' C). (Henry's law constants are available in U.S. EPA
[1990]). Removal efficiencies greater than 99 percent are difficult to achieve for certain compounds. In
general, other treatment technologies will be required for such chemicals when ground-water
concentrations are high (e.g., above 10.000 ppm or 1 percent).
Contaminant Fate
Contaminants are not destroyed by air stripping but are physically separated from contaminated ground
water and transferred to air. Depending on the level of contaminants in the air discharge, the contaminated
air stream may need further treatment. Additional polishing treatment of the aqueous effluent also may
be necessary, depending on discharge requirements.
Design
Air strippers are designed for a specific target chemical (either the predominant contaminant or the most
difficult-to-strip contaminant) with a desired target removal efficiency. The air stripping process is well
understood and the technology is well developed. Air stripping has an extensive track record in a variety
of applications.
The most frequently used configuration is a packed tower equipped with an air blower. The ground water
is fed into the top of the stripper and the air is introduced at the bottom, creating a countercurrent gas-liquid
contact. Random plastic packing is frequently used to improve gas-liquid contact. Structured packing and
steel packing may also be used. Packed-tower air stripper design involves specification of stripper column
diameter and packing height for a specified ground-water flow rate and air-to-water ratio. Shallow-tray
aeration devices provide an alternative gas-liquid contacting system that provides a more compact, lower
profile system that is less subject to fouling.
Alternative Techniques/Enhanced Methods
• For high flow rates (over 1.000 gpm), cooling towers (large structures with cascading water
primarily used to cool water using countercurrent ambient air flow) may provide a cost-effective
alternative to conventional packed towers.
• Shallow tray air strippers or diffused tank aeration units are less susceptible to fouling problems
than packed towers and may be preferable where the water to be treated contains high
concentrations of certain inorganics (e.g., iron).
D-l
-------
Appendix Dl: Air Stripping (continued)
Alternative Techniques/Enhanced Methods (continued)
• Because the efficiency of air stripping increases at higher temperatures, increasing the influent
ground-water temperature (typically about 55° F) using a heat exchanger can increase the stripper's
removal efficiency, especially for less volatile contaminants.
• Steam stripping methods, which use steam rather than air as the stripping medium, can be used to
remove highly soluble contaminants and SVOCs not usually amenable to air stripping. However
operation costs for steam stripping can be two to three times greater than air stripping, depending on
the cost of steam. In this guidance, these methods are not considered a type of air stripping and are
not identified as a presumptive technology for ex-situ treatment of ground water.
Pre/Post-treatment
• Pretreatment to remove iron and other metals and to control hardness may be necessary to reduce
fouling and mineral deposition in packed tower air strippers.
• Granular activated carbon is sometimes used to polish the treated water from an air stripper to further
reduce organic contaminant levels and meet discharge requirements.
• Contaminants in the air discharge may be reduced by activated carbon adsorption, catalytic
oxidation, or incineration to meet air emission requirements.
Selected References
Lamarre,B. 1993. Selecting an air stripper (what to consider!). The National EnvironmentalJoumal: 26-29.
Nyer, E.K. 1985. Groundwater Treatment Technologies. VanNostrand Reinhold. New York, NY. 187 pp.
Nyer,E.K. 1993. Practical Techniques for Groundwater and Sol Remediation. CRC Press, Inc., Boca Raton
FL 214pp. . '
Okoniewski, B.A. 1992. Remove VOCs from wastewater by air stripping. Chemical Engineering Progress:
89-93.
U.S. EPA Environmental Protection Agency. 1990. Hazardous Waste Treatment, Storage and Disposal
Facilities (TSDF) - Air Emission Models. EPA/450/3-87-026. Office of Air Quality Planning and Standards
Research Triangle Park, NC. Appendix D.
U.S. Environmental Protection Agency. 1991. Engineering Bulletin: Air Stripping of Aqueous Solutions
EPA/540/2-91/022. Office of Research and Development, Cincinnati, OH. 9 pp.
D-2
-------
endix D2: Granular Activated Carbon
Activated carbon removes contaminants from ground water by adsorption. The adsorption process takes
place in three steps: (1) contaminant migration to the external sorbent surface; (2) diffusion into the sorbent
pore structure; and (3) adsorption onto the sorbent surface. The principal form of activated carbon used
for ground-water treatment is granular activated carbon (GAC). GAC is an excellent sorbent due to its
large surface area, which generally ranges from 500 to 2,000 m2/g.
Applicability
GAC is applicable to a wide variety of contaminants including: halogenated volatile and semivolatile
organics. nonhatogenated volatile and semivolatile organics. PCBs. pesticides, dioxins/furans, most organic
corrosives, metals, radioactive materials, inorganic cyanides, and certain oxidizers. GAC is potentially
applicable to certain organic cyanides, and it is not applicable to asbestos, inorganic corrosives, and
reducers (U.S. EPA, 1991). GAC is sometimes used alone for ground-water treatment. However, GAC
is typically used for polishing aqueous effluents or controlling air emissions from other treatment
technologies.
The adsorption capacity of activated carbon varies for specific organic compounds and for different types
of GAC (based on the origin of coal and the percent binder used in the manufacture of the GAC).
Contaminant-specific adsorption isotherms for a given type of GAC are generally available from the carbon
manufacturer.
Contaminant Fate
Contaminants are not destroyed by carbon adsorption, but are physically separated from contaminated
water and transferred to carbon. After exhaustion, the spent carbon may be reactivated, regenerated,
incinerated, or disposed of. Thermal reactivation and incineration destroy most or all adsorbed organic
contaminants. Steam or hot gas regeneration is not appropriate for spent GAC from treatment of
contaminated ground water but can be used for spent GAC from air emission control devices. GAC used
for metals sorption may require disposal. If disposed of, spent GAC may have to be managed as a
hazardous waste.
Design
Activated carbon is a well-developed, widely used technology with many successful ground-water treatment
.applications, especially for secondary polishing of effluents from other treatment technologies.
Contaminated ground water is contacted with a fixed GAC bed in a vessel. Row direction is generally
vertically downward, although an upward flow configuration is also possible. Fixed-bed configurations are
also used for air emission control.
Adsorber design involves determining total carbon requirements and the number and dimensions of vessels
needed to house the carbon. The amount of carbon required for a given application depends on the
loading of adsorbable constituents in ground water (or contaminated air stream), the carbon's adsorption
capacity for these constituents, and the carbon reactivation (or regeneration) frequency. Depending on the
ground-water suspended solids content, it may be necessary to periodically backwash down flow carbon
beds to relieve pressure drop associated with solids accumulation.
Alternative Techniques/Enhanced Methods
• Staged bed (multiple beds operated in series) and pulsed bed (carbon beds operated with nearly
continuous "pulsed" addition of fresh carbon and withdrawal of spent carbon) designs can be used
if higher removal efficiencies are required.
D-3
-------
Appendix D2: Granular Activated Carbon (continued)
Alternative Techniques/Enhanced Methods (continued)
• Because the adsorption capacity of GAC is much higher for gas phase treatment than for liquid
phase treatment, it is often more economical to use an air stripper followed by gas phase GAC
to treat the air stripper exhaust than to use GAC alone for ground-water treatment.
• GAC is not identified as a presumptive technology for removal of metals dissolved
extracted ground water. Spent carbon used for metals removal can be difficult to
regenerate and may require treatment and/or disposal as a hazardous waste. Although
GAC can remove low concentrations of certain metals, it has not been widely used for this
purpose (U.S. EPA. 1991).
Pre/Post-treatment
• Pretreatment may be required to remove natural organic matter, such as fulvic and humic acids,
that may interfere with the adsorption of the target contaminants or rapidly exhaust the GAC.
• Naturally occurring radionuclldes, if present in ground water, can accumulate in the GAC
during treatment, which could result in potential exposure hazards for operating personnel
and the spent carbon may require treatment and/or disposal as hazardous waste.
«i Thermal reactivation, using heat alone or steam, is typically used as a post-treatment method
for the spent carbon. The carbon is reactivated in a high-temperature reactor under reducing
conditions. Most organic contaminants are thermally degraded during the reactivation process.
Selected References
Long, G.M. 1993. Clean up hydrocarbon contamination effectively. Chemical Engineering Progress,
89(5):58-67.
Stover, E.L. 1988. Treatment of herbicides in ground water. Ground Water Monitoring Review. 54-59.
Stenzel, M.H. 1993. Remove organics by activated carbon adsorption. Chemical Engineering Progress:
36-43.
U.S. Environmental Protection Agency. 1991. Engineering Bulletin: Granular Activated Carbon
Treatment. EPA/540/2-91/024. Office of Emergency and Remedial Response, Washington, D.C. 8pp.
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Appendix D3: Chemical/UV Oxidation
Chemical oxidation uses chemical oxidizing agents to destroy toxic organic chemicals and cyanide
compounds (CN) in ground water. Commonly used oxidizing agents include: ozone, hydrogen peroxide,
hypochlorites, chlorine, and chlorine dioxide. Ozone and hydrogen peroxide are generally preferred for
removing organics and CN from ground water because chlorine-based oxidants can produce toxic
byproducts (e.g.. HCI. chlorinated organics). Ultraviolet light (UV) is often used in conjunction with ozone
and/or hydrogen peroxide to promote faster and more complete destruction of organic compounds
(reaction rates may be increased by factors of 100 to 1,000).
Applicability
Chemical oxidation is applicable to both volatile and semivolatile organic compounds and cyanide
compounds. Chemical oxidation is potentially applicable to RGBs, dioxins/furans, and metals (oxidation
can be used to precipitate metals under certain conditions). Chemical oxidation is not applicable to
asbestos and radioactive materials (U.S. EPA, 1991).
Chemical oxidation generally is effective for concentrations less than 500 ugl_, but has been used for
certain compounds at concentrations ranging up to several thousand mg/L. UV can enhance the oxidation
of compounds that are resistant to chemical oxidation alone (e.g., PCBs). Iron or copper catalysts may
be required for efficient destruction of certain organic compounds (e.g., phenols).
Contaminant Fate
Complete oxidation decomposes hydrocarbons into carbon dioxide and water, although chlorinated organic
compounds also yield chloride ions. CN is oxidized to ammonia and bicarbonate by hydrogen peroxide in
an alkaline environment. If oxidation is incomplete, toxic constituents may remain, or intermediate
degradation products can be formed that may be toxic. These toxic substances may be removed using
GAG as a secondary or polishing treatment step.
Design
Chemical oxidation is a proven and effective technology that is carried out in either batch or continuous
reactors. Oxidants are generally added to contaminated ground water in a mixing tank prior to introduction
into the reaction vessel (reactor). The use of ozone as the oxidizing agent requires an onsite ozone
generator and an ozone decomposition unit or other ozone emission control device. The use of hydrogen
peroxide as the oxidizing agent requires storage tanks and special handling protocols to ensure operator
safety. The use of chlorine as the oxidizing agent may produce HCI gas. If HCI is produced, an acid gas
removal system may be necessary.
UV lamps, if used, are typically enclosed in quartz tubes submerged inside the reaction vessel. The tubes
are subject to fouling or scaling from compounds such as iron oxide or calcium carbonate and from
biological floes from microorganisms in ground water. If fouling occurs, oxidation rates are drastically
reduced.
Site-specific treatability studies are generally recommended for chemical oxidation systems. Extensive
pretreatment may be required to condition ground water for effective oxidation. If UV lamps are used, the
studies must evaluate the potential for fouling or scaling of the quartz tubes at the ground-water
composition, oxidant concentration, and UV intensity conditions anticipated for long-term system operation.
If fouling or scaling is likely, pretreatment and/or physical methods for keeping the tubes clean (e.g., wipers)
may be required. If metals are to be removed by oxidation, solids should be removed by clarification or
filtration prior to UV oxidation. Provisions for removing precipitated metal sludges also may be necessary.
D-5
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Appendix D3: Chemical/UV Oxidation (continued)
Alternative Techniques/Enhanced Methods
• UV radiation can be used in combination with a chemical oxidizing agent to increase the
effectiveness of oxidation, especially for difficult-to-oxidize compounds.
• Metal catalysts, such as iron or copper, can be used in combination with a chemical oxidizing
agent to increase the effectiveness of oxidation for certain types of compounds.
• Hydrodynamic captation is an innovative technology recently demonstrated under EPA's SITE
program that uses forced cavitation of gas to enhance destruction of prganics during UV oxidation
processes.
Pre/Post-treatment
• Pretreatment may be necessary to remove solids, microorganisms, calcium carbonate, iron
oxides, and/or other metals that can interfere with the oxidation process or UV transmission. A
pretreatment sequence of precipitation, flocculation, clarification, and/or filtration steps may be
necessary.
• Post-treatment of the aqueous effluent with GAC may be necessary if destruction is not complete
or if toxic byproducts are formed during oxidation.
• If toxic metals precipitate during the oxidation process, treatment and/or proper disposal of the
resulting sludge may be required.
Selected References
U.S. Environmental Protection Agency. 1990. CERCLA Site Discharges to POTWs Testability Manual.
EPA/540/2-90/008. Office of Emergency and Remedial Response. PB91-921269/CCE. NTIS.
Springfield, VA. pp. 11-7 to 11-17.
U.S. Environmental Protection Agency. 1991. Engineering Bulletin: Chemical Oxidation Treatment.
EPA/540/2-91/025. Office of Emergency and Remedial Response, Washington, D.C. 8 pp.
U.S. Environmental Protection Agency. 1993. Superfund Innovative Technology Evaluation Program.
Technology Profiles. Sixth Edition. EPA/540/R-93/526. Office of Research and Development.
Washington, DC.
U.S. Navy. 1993. UV/Oxidation Treatment of Organics in Ground Water. NEESA Document Number
20.2-051.7. Navy Energy and Environment Support Activity, Port Hueneme, CA. 11 pp.
D-6
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Appendix D4: Aerobic Biological Reactors
Biological reactors use microorganisms to degrade organic contaminants in ground water in ex situ
reactors. There are two basic types of ex situ biological treatment processes: aerobic reactors and
anaerobic reactors. Aerobic reactors use oxygen to promote biodegradation and are widely used.
Anaerobic reactors degrade organics in the absence of oxygen. This guidance focuses on aerobic
biological treatment because anaerobic treatment processes are not widely used for ground-water
treatment.
Applicability
Aerobic biological reactors are applicable to a wide variety of halogenated and nonhalogenated volatile and
semivolatile organics. Aerobic biological reactors are potentially applicable to heavy organics, such as
PCBs and certain pesticides, and organic and inorganic cyanides, but are generally not as effective for such
recalcitrant compounds. Aerobic processes are not applicable to metals, asbestos, radioactive materials,
or corrosive or reactive chemicals (U.S. EPA, 1992).
Contaminant Fate
Organic compounds are decomposed to carbon dioxide and water (aerobic processes) or to methane and
carbon dioxide (anaerobic processes). Volatile organics are also removed by volatilization as a competing
mechanism. Microbial growth produces an excess organic sludge (biomass) that must be disposed of
properly. This sludge may concentrate metals and recalcitrant organic compounds that are resistant to
degradation. Biodegradation may produce decomposition byproducts that are emitted to the air or
dissolved in the effluent, and these decomposition byproducts may require additional treatment.
Design
Ex situ biological treatment of ground water is conducted in bioreactors. The primary factors influencing
bioreactor design are the microbia) organic utilization rates and the peak organic loading rate (i.e., flow rate
times organic concentration). Treatability tests are necessary to determine these and other design
parameters. Under most circumstances, bioreactors require a significant startup time to acclimate the
microorganisms to the specific contaminants being treated before the bioreactor will operate at optimal
degradation rates. There are two general types of bioreactor design:
• In suspended growth reactors, microbes are kept suspended in water using mechanical
. aerators or diffused air systems. These aeration systems also keep the solution well mixed,
improving contact between microbes and dissolved contaminants and supplying oxygen to the
system. Activated sludge systems are the most common suspended growth bioreactors. Other
examples include aerated ponds or lagoons, stabilization ponds (using both algae and bacteria),
and sequencing batch reactors.
• In attached growth reactors, biomass is attached to a solid substrate, such as sand, rock,
plastic, activated carbon, or resin. Reactor design is dependent upon the surface area of
substrate media available for biomass growth. Examples include trickling filter, rotating
. biological contactor, fluidized bed, fixed bed, and roughing filter designs.
Alternative Techniques/Enhanced Methods
• Direct addition of powdered activated carbon (PAC) into suspended growth bioreactors can both
improve removal efficiency and reduce the likelihood of process upsets by buffering the
concentrations of toxic compounds at levels amenable to biodegradation.
D-7
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Appendix D4: Aerobic Biological Reactors (continued)
Alternative Techniques/Enhanced Methods (continued)
• Microbial augmentation (the addition of specially cultured microorganisms) may be used to
increase the system's removal efficiency for certain difficult-to-degrade contaminants.
• Anaerobic reactors (digesters) may be preferred for the treatment of certain ground-water
contaminants (e.g., certain chlorinated organics) that are difficult to degrade aerobfcally
However, anaerob.c reactors have not been identified as a presumptive technology for
he following reasons: 1) anaerobic processes have not been widely used for ground-water
treatment; 2) reaction rates, are slower than for aerobic processes, which result in longer
startup times (for accl.rnat.on) and longer treatment times; and 3) such reactors havfa
greater sensitivity to process upsets, especially where flow and contaminant concentrations
vary over t,me These factors generally result in higher operation and
lower performance efffctencfes man for
Pre/Post-treatment
• Chemical precipitation (for metals) or other pretreatment (e.g., PAC addition for organics) may
be required to reduce (or buffer) concentrations of compounds that are toxic to
microorganisms.
• Carbon adsorption post-treatment may be used to reduce contaminant concentrations in the
treated water to meet discharge requirements.
• Because certain aerated bforeactor designs (e.g., mechanically aerated activated sludge
systems, aerated ponds and lagoons) present difficulties for djrect capture and control of air
ermss.ons, an air stripper (with emission controls) may be a cost-effective treatment prior to
bodegradaton rf volatile contaminant emissions need to be controlled. For other bioreactor
designs, such as drffused-aeration activated sludge and trickling filter systems, air emissions
are more easily captured and pan be treated using carbon adsorption, catalytic oxklatfon or
incinsrstion.
Selected References
1985. Wastewater treatment. Chemical
Flatman P.E., D.E. Jerger, and L.S. Bottomley. 1989. Remediation of contaminated groundwater
using biological techniques. Ground Water Monitoring Review. 1 05-11 9. grounowater
U.S Environmental Protection Agency. 1979. Selected Biodegradation Techniques for Treatment
EPA-^-79-006. Off,e'of Research a'nd'
U.S Environrnental Protection Agency. 1 981 . Literature Study of the Biodegradability of Chemicals
in Water (Volume 1. B.odegradability Prediction, Advances in and Chemical Interferences wih
WasteWater Treatment). EPA/R806699-01 . Offk:e of Research and Development
U.S. Environmental Protection Agency. 1992. Engineering Bulletin: Rotatinq Biolooical Contactor*
EPA/540/S-92/007. Office of Research and Development. Cincinnati. OH f pp Contactors-
D-8
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Appendix DS: Chemical Precipitation
Chemical precipitation chemically converts dissolved metal and/or other inorganic ions in ground water into
an insoluble form, or precipitate. Metal ions generally precipitate out as hydroxides, sulfides, or carbonates
and are removed as solids through clarification and filtration. In this guidance, chemical precipitation is
defined to include chemical precipitation of metals by oxidizing or reducing agents as well as any pH
adjustment (neutralization) and solids removal steps required.
Applicability
Chemical precipitation is applicable to dissolved metal and other inorganic ions (such as arsenate and
phosphate). Chemical precipitation is not applicable to volatile or semivolatile organic compounds (U S
Navy, 1993). a r- \ • •
Contaminant Fate
Dissolved metals are converted to insoluble forms, which are subsequently removed by flocculation,
clarification, and/or filtration. The solid residue (chemical sludge) containing the metal contaminant then
must be treated and/or disposed of properly.
Design
The process generally takes place at ambient temperatures. Batch reactors are generally favored for lower
flowrates (e.g.. up to about 50.000 gpd). and usually use two tanks operating in parallel. Each tank can
act as a flow equalizer, reactor, and settler, thus eliminating separate equipment for these steps.
Continuous systems have a chemical feeder, flash mixer, ftocculator. settling unit, filtration system (if used).
and control system for feed regulation. Site-specific treatabilfty tests are required to determine the optimum
type and dosage of precipitation chemicals, necessary pretreatment steps, and post-treatment
requirements for aqueous effluent and sludge residuals.
There are three types of precipitation chemicals:
• Metal hydroxides are formed by the addition of alkaline reagents (lime or sodium hydroxide).
Precipitation is then initiated by adjusting pH to the optimum level for the particular metal ion.
Maintaining pH levels within a relatively narrow optimum range is usually necessary to achieve
adequate metal precipitation. Pretreatment with oxidizing or reducing chemicals (e.g.. hydrogen
peroxide, ferrous sutfate) may be necessary to precipitate some metals (e.g.. iron, manganese,
chromium) in their least soluble form. Natural organic matter can inhibit the formation of
insoluble metal hydroxides by forming metal-organic complexes. Metal hydroxide precipitation
is typically effective for arsenic, cadmium, chromium (+3), nickel, zinc, manganese, copper (+2),
tin (+3), and iron (+3).
• Metal sulfides are formed by the addition of either soluble sulfides (e.g., hydrogen sulfide.
sodium sulfide. or sodium bisulfide) insoluble sulfides (e.g.. ferrous sulfide). Sodium sulfide and
sodium bisulfide are most commonly used. Sulfur dioxide and sulfur metabisulfite have also
• been demonstrated for chromium reduction prior to precipitation. Metal sulfides have lower
solubilities than metal hydroxides, and effective metal removal efficiencies can be achieved over
a broader pH range. The method is mainly used to remove mercury and lead and may be used
to remove arsenic, cadmium, chromium (+3,or +6). silver and others. Sulfide precipitation also
can be used to treat filtered ground water after hydroxide precipitation.
D-9
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Appendix D5: Chemical Precipitation (continued)
Alternative Techniques/Enhanced Mathods
• Metal carbonates are formed by the addition of calcium carbonate or by adding carbon dioxide to
metal hydroxides. Solubilities of metal carbonates are intermediate between the solubilities of metal
hydroxides and metal sulfides. Insoluble metal carbonates are easily filtered from treated ground
water. The method is particularly good for precipitating lead, cadmium, and antimony.
• Sodium xanthate has shown promise as a precipitation agent similar to sodium surf ide.
Pre/Post-treatonent
• Pretreatmerrt to adjust pH is normally required to obtain the lowest precipitate solubility.
• Pretreatment may be necessary to oxidize Iron or manganese compounds or reduce hexavatent
chromium compounds Into forms that can be readily precipitated.
• Depending on discharge requirements, the aqueous effluent may need pH adjustment and/or
further polishing. Activated alumina or ion exchange media are regenerabte treatment options for
effluent polishing for metals. Activated carbon also may be used but spent carbon may require
treatment and disposal as a hazardous waste.
• The sludge may require stabilization treatment by addition of lime/fly ash or portend cement to
reduce permeability and the teachability of metals prior to disposal. In some cases, metals may
be recovered from the residue for reuse, but this is generally not economical.
Selected Raferenc&t
**
Monopoli, A.V. 1993. Removing dissolved inorganics from industrial wastewater. The National
Environmental Journal: 52-56.
U.S. Environmental Protection Agency. 1987. Handbook on Treatment of Hazardous Waste Leachate.
EPA/600/8:87/006. Office of Research and Development, Cincinnati. OH. pp. 44-45.
U.S. Environmental Protection Agency. 1990. CERCLA Site Discharges to POTWs Treatability Manual.
EPA/540/2-90/008. Office of Emergency and Remedial Response. PB91-921269/CCE. NTIS,
Springfield. VA. pp. 11 -23 to 11 -36.
U.S. Navy. 1993. Precipitation of Metals from Ground Water. NEESA Document Number 20.2-051.6.
Navy Energy and Environment Support Activity. Port Hueneme, CA. 11 pp.
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Appendix D6: Ion Exchange/Adsorption
Ion exchange removes metal contaminants from water by passing contaminated ground water through
a granular solid or other porous material, usually an impregnated resin, that exchanges sorbed ions
(e.g.. H*. OH". Na*. Li*. CCV) for contaminants dissolved in ground water. The ion exchange media
are selected to nave sorptive affinity for the tonic forms (cation or anion) of the contaminants being
removed. The ion exchange media can therefore be either cationic. anionic. or a mixture of the two.
Because ion exchange is a reversible process, resins can be regenerated by backwashing with a
regeneration solution (e.g.. brine; strong or weak acids or bases). Conventional ion exchange resins
are generally too costly for large-scale ground-water treatment and ara predominantly used for
polishing of aqueous effluents after Other treatment processes.
Applicability
Ion exchange is applicable to ionic contaminants such as dissolved metals or nitrates. Ion exchange is
not applicable to non-ionic contaminants such as most organic compounds. "
Contaminant Fate
Contaminants are removed from ground water through sorptjon onto the exchange media. When most
of the exchange sites of the media become filled, the exchange media are regenerated by backflushing
with a suitable regeneration solution. The concentrated backf lush solution must then be disposed of or
stripped of its contaminants. Exchange resins can generally be regenerated many times and have a
relatively long useful life. .
Design
Various resin types are available to tailor systems to discrete ionic mixes. For example, acid
exchangers replace cations in water with hydrogen ions and base'exchangers replace anions with
hydroxide ions. Weak acid and base exchangers are selective for more easily removed tons while
strong acid and base exchangers are less selective, removing most tons in the ground water.
Generally, ease of cation and anton removal follows an affinity sequence specific to the tons in
question. Synthetic resins are available with unique selectivity sequences. The wide variety of resins
and other ion exchange media (e.g.. activated alumina, biological materials) that are available make the
selection of an appropriate exchange media a critical design step. Information on the applicability of
specific resins may be obtained from resin manufacturers. In addition, ion exchange resins generally
have an optimum pH range for effective metals removal. pH control may be required to achieve
maximum removal efficiency from ground water.
A typical ion exchange installation has two fixed beds of resin. While one is in operation, the other is
regenerated. Batch, fixed column, and continuous column bed designs can be used. Downflow
column designs are generally preferred. Continuous column systems eliminate the need for
backwashing but are not commonly used because of the complexity of the resin removal mechanics.
Flow rates up to 7.000 gpm have been reported for ion exchange systems. However, conventional ion
exchange is generally cost-effective for ground-water treatment only at low flow rates or low
contaminant concentrations. It is therefore primarily used as a polishing step following chemical
precipitation or other treatment.
D-ll
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Appendix D6: Ion Exchange/Adsorption (continued)
Alternative Techniques/Enhanced Methods
• Activated alumina is an anionic exchange medium comprised of granulated dehydrated
aluminum hydroxide. Activated alumina is effective for removing fluoride, selenium, chromium
(+6). and arsenic ions, which are exchanged for hydroxide ions. Adjustment of pH may be
necessary to achieve optimal removal efficiency. The alumina is regenerated with a sodium
hydroxide solution.
o Biological materials (e.g.. algae, crop residues) have recently shown great promise as an
innovative ion exchange media for metals. Biological media are significantly less costly than
conventional resins (cents per pound vs. dollars per pound), and may become more commonly
used for metals removal from ground water.
» Eleetrodialysis uses alternately placed cation and anion permeable membranes (made of Ion
exchange resin) and an electrical potential to separate or concentrate tonic species.
• Activated carbon adsorption can also be used to remove inorganics at tow concentrations
However activated carbon is not Identified as a presumptive technology for removal of
metals dissolved extracted ground water. Spent carbon used for me'als removal can be
difficult to regenerate and may require treatment and/or disposal as a hazardous waste.
Pre/Post-treatment
• Pretreatment may be required to remove suspended solids at concentrations greater than
about 25 mg/L or oil at concentrations greater than about 20 mg/L. Urge organic molecules
also can clog resin pores and may need to be removed.
• pH adjustment may be necessary to achieve optimal metajs removal.
• The backwash regeneration solution must be treated to remove contaminants.
• PosWreatment of spent ion exchange media may be required to recover concentrated
contaminants or management as a hazardous waste may be required.
Selected References
Clifford p.. Subramonian, S., and Sorg, T.J.. 1986. "Removing Dissolved Inorganic Contaminants
from Water. Environmental Science and Technology, Vol. 20. No. 11.
Nyer, E.K. 1985. Groundwater Treatment Technologies. Van Nostrand Reinhold. New York. NY.
lo/ pp.
U.S. Environmental Protection Agency. 1990. CERCLA Site Discharges toPOTWs Tnatability
MT,cUao EP^5?P/2-90/0°8. Office of Emergency and Remedial Response. PB91-921269/CCE
NTIS. Spnngfield, VA. pp. 11-102 to 11-112.
D-12
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Appendix D7: Electrochemical Methods
Electrochemical processes use direct electrical current applied between two immersed electrodes to
drive' chemical oxidation-reduction reactions in an aqueous solution. Historically, electrochemical
processes have been used to purify crude metals or to recover precious metals from aqueous
solutions. Positively charged metal ions are attracted to the negatively charged electrode (the
cathode), where they are reduced. The reduced metals typically form a metallic deposit on the
cathode. Negatively charged ions are attracted to the positively charged electrode (the anode), where
they are oxidized.
For contaminated ground water treatment, electrochemical cells have been used for the reduction (and
subsequent precipitation) of hexavalent chromium to trivalent chromium. In this process, consumable
iron electrodes are used to produce ferrous ions (Fe2*) at the anode and hydroxide ions (OH") at the
cathode. An oxidation-reduction reaction then occurs between the ferrous, chromium, and hydroxide
ions to produce ferric hydroxide Fe(OH)3 and chromic hydroxide Cr(OH)3. which subsequently
precipitate from solution.
Applicability
Electrochemical processes are applicable to dissolved metals. It is most commonly used in ground
water treatment for the reduction and precipitation of hexavalent chromium. The process also may be
. applicable to removing other heavy metals including arsenic, cadmium, molybdenum, aluminum, zinc,
and copper ions. Electrochemical processes have also been used for the oxidation of cyanide wastes
(at concentrations up to 10 percent). Electrochemical processes are not applicable to organic
compounds or asbestos.
Contaminant Fate
Dissolved metals either deposit on the cathode or precipitate from solution. Precipitates form an
inorganic sludge that must be treated and/or disposed of, typically in a landfill. Spent acid solution,
which is used to periodically remove deposits formed on the electrodes, will also require proper
treatment and disposal. Cyanide ions are hydrolyzed at the anode to produce ammonia, urea, and
carbon dioxide.
: ',
Design
Electrochemical reactors generally operate at ambient temperatures and neutral pHs. Both batch
reactors and continuous flow reactors are commercially available. A typical electrochemical cell for
hexavalent chromium reduction consists of a tank, consumable iron electrodes, and a direct current
electrical supply system. An acid solution is used to periodically clean the iron electrodes, which need
to be replaced when they are significantly consumed. Reactor residence times required for treatment
depend on the contaminants present as well as the degree of mixing and current density. Reduction of
hexavalent chromium generally requires short residence times (approximately 10 seconds), whereas
treatment of cyanide compounds requires longer process times.
Pre/Post-treatment
• Pretreatment may be necessary to remove suspended solids.
• Settling or clarification post-treatment may be necessary to remove the precipitated
trivalent chromic and ferric hydroxides formed during hexavalent chromium
electrochemical reduction.
D-13
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Appendix D7: Electrochemical Methods (continued)
Pre/Post-treatment (continued)
• The sludge may require stabilization prior to disposal by addition of lime/fly ash or portland cement
to reduce permeability and metal teachability. In some cases, metals may be recovered from the
plated electrode or precipitated residue, but this is generally not economical for typical ground-
water applications.
Selected References
Engiund, H.M. and L. F. Mafrica. 1987. Treatment Technologies for Hazardous Waste. APCA Reprint
Series RS-13. Air Pollution Control Association, Pittsburgh, PA. pp. 43-44.
U.S. Environmental Protectkjn Agency. 1990. A Compendium of Technologies Used in the Treatment of
Hazardous Wastes. EPA/625/8-87/014. Office of Research and Development. PB91 -90-274093. NTIS.
Springfield, VA. p. 23.
D-14
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Appendix O8: Aeration of Background Metals
Aeration (contact with air) removes some metals from water by promoting chemical oxidation and the
formation of (nsdubte hydroxides that precipitate from the water. Aeration for metals removal differs from
air stripping in that precipitation rather than volatilization is the desired effect of the technology
Applicability
Aeration techniques are useful for the removal of limited number of dissolved cations and soluble metal
compounds. This method is well suited for the removal of background metals such as iron and manganese
which is necessary as part of a selected remedy such as pretreatment to air stripping. Methods of aeration
for metals include aeration tanks, aeration basins, or cascade aeration. Aeration methods are usually not
sufficient as an independent technology for iron and manganese, but are utilized as a step in the treatment
process. Often, the air-water contact in tank and cascade aeration is not enough to obtain high removal
efficiencies. Spray basins are limited by area, wind, and ice particle formation (Nyer, 1985).
Contaminant Fate
Dissolved metais are oxxized to insoluble hydroxides which precipitate from solution, and can then can be
subsequently removed by ftocculation, sedimentation, and/or filtration.'
Design
The three types of aeration systems:
• Aeration tanks bubble compressed air through a tank of water.
• Cascade aeration occurs when air is made by turbulent flow and agitation.
• Spray or aeration basins use an earthen or concrete basin with a piping grid and spray nozzles that
spray the water Into the air In very fine droplets.
Related methods include aeration used to remove volatile organic contaminants from water are considered
to be a type of air stripping, as discussed In Section 2.1.1. The use of aeration to promote aerobic
biological treatment processes is considered to be an element of biological treatment as discussed in
Section 2.1.4.
Pre/Post Treatment
• Aeration is often a pretreatment for other remediation technologies, such as air stripping, to remove
certain metals.
• • Aeration can be followed by other treatments such as flocculation, sedimentation, and/or filtration to
remove oxidized metals.
D-15
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Appendix D8: Aeration of Background Metals
Selected References
Betz. 1962. Betz Handbook of Industrial Water Conditioning. Trevose. PA. pp.19-22
Nyer, E.K. 1985. Groundwater Treatment Technologies. Van Nostrand Reinhold New York NY
187pp. ' '
Nyer. E.K. 1993. Practical Techniques for Groundwater and Soil Remediation. CRC Press Inc
Boca Raton, FL. 214 pp. '
D-I6
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. D.C. 20460
JUN U 1995
OFFICE OF
GENERALCOUNSEL
MEMORAMDDM
SUBJECT!
FROM:
Presumptive Remedies
James E. Costel
CERCLA Administra
ORC Region VI
George B. Wyeth
Attorney
Solid Waste a
CP Compliance
ihairperson
e Records Workgroup
/
UMA,
•J
gency Response Division (2366)
TO:
I.
CERCLA Branch Chiefs
Office of Regional Counsel
Regions I - X
Purpose
This memorandum explains the relationship of EPA's
presumptive remedies initiative for Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA) site
remediation to the requirements of the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP), 40 CFR Part 300. In
addition, this is to suggest methods for meeting the NCP
administrative record requirements for Superfund sites where
presumptive remedies are considered. We are providing this
information in response to questions that have been brought to
the CERCLA Administrative Records Workgroup and the Office of
General Counsel.
• Presumptive remedies are preferred technologies for
addressing common types of sites such as municipal landfills or
sites with VOCs in soil,1 based on historical patterns of remedy
selection and EPA's scientific and engineering evaluation of
1 As these examples indicate, "site types" may be defined in
a variety of ways, including the nature of the facility involved,
the type of waste present, or possibly other criteria.
Printed on Rtcyclcd Paper
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performance data on technology implementation. EPA has issued
directives explaining its recommendations regarding the use of
presumptive remedies to expedite remediation at certain types of
CERCLA sites. Ss& e.g. Presumptive Remedies: Policy and •
Procedures, September 1993 (OSWER Directive 9355.0-47FS);
Presumptive .Remedies: Site Characterization and Technology
Selection for CERCLA Sites With Volatile Organic Compounds In
Soils, September 1993 (OSWER Directive 9355.0-48FS); Presumptive
Remedy for CERCLA Municipal Landfill Sites, September 1993 (OSWER
Directive 9355.0-49FS). The presumptive remedy initiative is
intended to make CERCLA responses faster and more efficient. The
initiative is part of the Superfund Accelerated Cleanup Model
(SACM). *
The relationship of the presumptive remedy initiative to
the requirements of the National Contingency Plan, and especially
the NCP requirements relating to the administrative record, has
never been expressly addressed in EPA guidance. The CERCLA
Administrative Records Workgroup has, therefore, prepared this
memorandum explaining how the presumptive remedies initiative
comports with the NCP, and how the administrative record should
be developed for a presumptive remedy site. This memorandum
suggests steps that can be taken to help ensure that use of
presumptive remedies is consistent with the NCP. In particular,
this memorandum suggests steps to be taken to ensure that a
complete administrative record is prepared for sites at which
presumptive remedies are used. A complete administrative record, ,
as described in this memorandum, will show that complete NCP
remedy selection procedures were followed at a CERCLA site where
the presumptive remedies initiative is used. In that many
factors involved in the use of presumptive remedies are site-
specific, the suggested approaches in this memorandum are
expressed in terms of what "generally" should be done, other
approaches may be more appropriate in some cases depending upon
the circumstances, and regional counsel should use their
professional judgement in this regard.3
The presumptive remedy directives generally focus on
remedial, rather than removal, actions (e.g., they analyze the
presumptive remedy in terms of the criteria for remedy
selection). However, the information they provide will generally
be adequate to support the use of presumptive approaches in
removals as well, where appropriate (e.g., for non-time-critical
removals). Similarly, the discussion here, while focusing on the
remedial process, is generally applicable to removals as well.
3For a general introduction to presumptive remedies, and
explanation of Agency policies on their use, see Presumptive
Remedies: Policy and Procedures, September 1993 (OSWER Directive
9355.0-47FS).
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II. Executive
The use of presumptive remedies advances the NCP remedy-
selection objectives in that the presumptive remedy initiative
promotes consistency in decision-making. The use of presumptive
remedies as part of the remedy selection process is also
consistent with the program management principle that site-
specific documentation and analysis should be tailored to the
scope and complexity of the problems being addressed.. 40 CFR §
300.430(a)(l)(ii)(C).
The use of presumptive remedies does not avoid compliance
with the remedy selection process in 40 CFR § 300.430. The use
of presumptiye remedies follows the NCP remedy selection process
because the identification of presumptive remedies serves, in
effect, to carry out the screening and detailed analysis steps in
a generic manner that minimizes the need to perform those steps
at a site-specific level.
In order to meet the Administrative Record requirements for
presumptive remedies, it is recommended that the administrative
record for a presumptive remedy site generally should include the
following: (1) relevant OSWER generic presumptive remedy
documents; (2) a "bridging" memorandum or other documentation
which shows that the presumptive remedy fits the site; (3) a
site-specific analysis discussing how the presumptive remedy fits
under the three site-specific remedy selection criteria (state
ARAR compliance, state acceptance and community acceptance);
(4) EPA's written responses to comments which pertain to EPA's
decisions regarding the use of presumptive remedies; (5) a site-
specific response to any comments regarding new technology; and
(6) a notice in the administrative record file and in the
administrative record file index regarding the availability of
the data upon which the presumptive remedy is based.
III. Presumptive remedies are consistent with the MCP.
The purpose of the presumptive remedies initiative is to use
the Superfund program's past experience to streamline site
investigations and speed up selection of cleanup actions. Where
EPA's experience and technical knowledge show that a single
technology, or limited group of technologies, will generally be
the most appropriate remedy for a particular type of site or
waste, it would be inefficient to routinely continue analyzing a
wider range of technologies at each such site. By identifying
"presumptive" remedies, EPA can narrow and focus feasibility
studies, and allow such studies to move ahead to narrower issues
that might in the past have been put off to the design stage.
This should lead to better-focused feasibility studies, and to
faster progress from remedy selection to remedy implementation.
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While the presumptive remedy approach is not expressly
addressed in the NCP, it is fully consistent with the NCP.
A. The use of presumptive remedies advances NCP remedy-
selection objectives.
The use of presumptive remedies advances NCP remedy-
selection objectives as follows:
1. The presumptive remedy initiative promotes
consistency in decision-making.
One objective of the NCP's requirements for selecting
remedies is to provide a uniform framework to promote consistency
in decision-making. 55 Fed. Reg. 8666, 8700 (March 8, 1990).
The use of presumptive remedies, when appropriate, also helps
ensure that EPA is consistent in its decision-making, and it
meets this NCP objective. That is, by using the presumptive
remedy as a point of departure in the remedy selection process
for addressing specific types of sites with similar
characteristics, EPA advances a consistent remedy selection
process at appropriate sites.
2 . The use of presumptive remedies as part of the
remedy selection process at appropriate sites is
consistent with the program management principle
in § 300.430(a) (1)
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B • Tho USQ of presui
selection process.
The use of presumptive remedies is also consistent with the
remedy selection process set forth in the NCP. That process
involves severa.l steps: characterizing the risks presented by the
site, screening technologies for possible remediation, and
performing a detailed analysis of those technologies that appear
most promising. The screening step is based on three criteria
(effectiveness, implementability, and cost), excluding
.technologies that are clearly inferior (for example, where the
cost is "grossly excessive compared to the overall effectiveness
of alternatives"(ss& 40 CFR § 300.430(e)(7)(iii))). The detailed
analysis step is based on nine criteria set forth in 40 CFR §
300.430(e)(9)(iii).
The identification of presumptive remedies serves, in
effect, to carry out the screening and detailed analysis steps in
a generic manner that minimizes the need to perform those steps
at a site-specific level. In developing a presumptive remedy for
a certain type of site, or sites containing a certain type of
waste, EPA evaluates technologies that are commonly considered
for a certain type of site and identifies one or more
technologies as being generally most appropriate. Part of the
selection of a presumptive remedy is a comparison of various
possible technologies for such sites under the nine remedy
selection criteria set out in the NCP.4
Where circumstances at a site correspond to those for which
the presumptive remedy was identified as generally suitable, the
generic analysis of the NCP remedy selection criteria that was
performed in identifying the presumptive remedy should be
adequate, and need not be repeated site-specifically. Therefore,
once initial data collection confirms that a site is of a type
for which presumptive remedies exist, a focused feasibility study
(FS) may be prepared, focusing only on the presumptive remedy
(which may be general enough to allow for several alternatives),
"in most cases, the nine criteria for the detailed analysis
of alternatives, rather than the three initial screening
criteria, are used to identify presumptive remedies. While the
.identification of presumptive remedies performs a function
similar to the initial screening step in some respects, it is not
limited to excluding technologies that are grossly inappropriate.
Therefore, the nine criteria used in the detailed analysis of
alternatives are more relevant to the presumptive remedy choice.
It should also be noted that certain criteria cannot be analyzed
at a national level: compliance with state ARARs, state
acceptance and community acceptance. Analysis of these criteria
is discussed below.
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and the no action alternative.5 In effect, as will be discussed
in more detail below, the materials prepared in the generic
analysis will substitute for a broader FS. Similarly, the
technology identification and screening steps done for the
generic presumptive remedy analysis will serve as the technology
and screening steps for the site at hand.
Some NCP criteria are, by their nature, invariably site-
specific: compliance with state ARARs, community acceptance, and
state acceptance.6 Therefore, the generic analysis of the remedy
selection criteria cannot address these factors, and they will
have to be addressed in the site-specific analysis. However, the
site-specific analysis need not examine technologies that were
considered and rejected in the generic presumptive remedy
analysis, unless it appears that the presumptive remedy fares so
poorly under one of the site-specific criteria as to call its
appropriateness seriously into question.7 In that case,
5The "Quick Reference Fact Sheet" entitled "Presumptive
Remedies: Policy and Procedures" (OSWER Directive 9355.0-47FS)
states at page 4 that:
... In most cases, after a site is confirmed as being a
type for which presumptive remedies exist, a focused FS
or EE/CA which eliminates the technology identification
and screening step would be prepared....
(emphasis added). To avoid any confusion, this statement means
that the NCP requirements for the technology identification and
screening step are fulfilled by the presumptive remedy
development materials, not that the existence of the presumptive
remedy guidance means that step is no longer needed. The
availability of the presumptive remedy materials simply obviates
the need for further site-specific screening.
6 In some cases, circumstances at a site may differ in some
respects from the "typical" site for which the presumptive remedy
is recommended. In such cases, the site specific record should
address whether the differences affect the assessment of the
presumptive remedy under the nine criteria. In unusual cases, it
is possible that generally recommended remedies may be rejected,
or that generally rejected remedies may be selected, based on
exceptional site conditions. The presumptive remedy approach
does not preclude such adjustments; it is intended to be a tool
for streamlining decisions and not a straightjacket for imposing
inappropriate remedies.
This may raise a concern that, with regard to those
criteria, there has never been a direct comparison of the
presumptive remedy with the other rejected technologies.
However, the approach recommended here reflects the fact that on
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IV.
A.
record for each site.
the
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i. The adminiatgafcive record for a mraaumptiye remedy 8ite
SHOT** include tha relevanfc oswER generic presumptive remedy
documents.
First, the record should include the relevant generic
presumptive remedy materials issued by the Office of Solid Waste
and Emergency Response (OSWER). In most cases, these will
consist of the following:
(a) Presumptive Remedies: Policy and Procedures, September
1993 (OSWER Directive 9355.0-47FS);
(b) The OSWER directive (usually in the form of a fact
sheet) explaining which technology or technologies are
recommended for the site type;
(c) An"analysis of the technologies that were rejected
(sometimes referred to as a "Feasibility Study
Analysis"); and
(d) Technical documents and other supporting materials that
were used in developing the OSWER Directive(s)^
concerning the presumptive remedy in question.*
Together, these documents provide information regarding a variety
of possible technologies and a comparison of each of those
technologies under those remedy selection criteria that are not
inherently site-specific. In effect, these documents serve as a
generic FS establishing that technologies other than those
recommended in the directive are generally not preferred under
the NCP's criteria for remedy selection.
The conclusions in the generic materials about the
appropriateness of a particular technology are sometimes
qualified. This is because the suitability of a given technology
may vary depending on site-specific conditions. Therefore, while
technology, which was considered and rejected at other sites, may
be unsuitable generally, it may be suitable at least for further
consideration in exceptional cases at certain sites where the
conditions that limited its usefulness are not present. Before
choosing the presumptive remedy approach, EPA personnel may
review the remedial investigation (RI) and the FS analysis to
determine whether unusual site conditions might warrant studying
a technology that would normally be excluded for that site type.
Because these supporting materials tend to be bulky, and of
limited public information value, steps that may be taken to
avoid unnecessary administrative burden while ensuring that they
are available as needed are discussed below in part IV.D.
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Sffi glKnaM l^nlud® a "b^dfrJBq" aemor.
flmMLJte.CTm»ntmtion srliiefr aliQira thftt ft
__ jcanQdv fifcs jflMt gj.te fif
- —M CMlia«g«d» but datarminad to frff
inapggQigrAata, tft*t determinate an7^^ ^
documafflt:e^ ^ wiglll ^^^ -™™™™ •HVMIM i^
cases8?^0^^^6;^^1?10 documentation is needed in almost all
afw *.C fuPP°rt the determination that the site is a good "fit"
with the type of site for which the presumptive remedy was
regommended, and that unusual site conditions do not appear to
YJr™£ de£artln9 £roa that recommendation. This documentation
is needed because the generic analysis of alternatives under the
remedy selection criteria is necessarily based on typical
conditions at a general site type. If conditions at a particular
«i«o™I- S19nifi°antly from those previously assumed, the
presumptive remedy may not be appropriate.
<=,^^.11? m°sj ca?es' a brief "bridging" memorandum may be
sufficient to show that conditions are similar to those assumed
in the generic analysis; in other cases, a more detailed analysis
may be needed. To the extent that any characteristics of the
site differ from those identified for the presumptive remedy the
record generally should reflect how EPA has analyzed this'
difference *nd whether any modification of the presumptive remedy
!»«*/??"• ^"'P16' wl?ere a dump site is similar to a municipal
landfill, but contains very unusual kinds of wastes not normally
found in such landfills, the site-specific record should aSJress
whether anything about those wastes would make the engineering
?»n55?if specified in the presumptive remedy for municipal *
landfills (primarily containment of the landfill mass and
?oii5v n1J?d/?ritre^inent °f landfi11
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.10
3. The administrative racord^or a PrcSilMlrtiyq raffl^Y site
should inelMde a ait®-sB@eif ic analysis diacMSging how
the presumptive remedy fits under the three sltfl-
apeeiffic remedy selection criteria (sta,t@ AR&R
compliance, state acceptance and community acceptance) .
Third, as discussed above, a site-specific analysis must be
prepared discussing how the presumptive remedy fits under the
three site-specific remedy selection criteria (state ARAR
compliance, state acceptance and community acceptance) . This
analysis should be included in the administrative record. Again,
in some cases a short bridging memorandum may be sufficient; in
other cases the analysis may be more complex (and a serious
problem may suggest a need to consider other alternatives) .
B. Administrative records sfaottlfl includ* IFft's
to comments tghiefe challenge BP&'S
the ua@ of presumptive remedies.
Special administrative record considerations arise if
outside parties submit comments supporting technologies other
than those recommended in the generic guidance. Since the
presumptive remedies are only policy, and are not legally
binding, it is important to ensure that all such comments are
adequately addressed. It will not be sufficient simply to reject
the comment on the ground that a presumptive remedy has been
selected for this site type. EPA's responses to comments which
challenge EPA's decisions regarding presumptive remedies should
be included in the administrative record.
It may be possible to respond to comments by relying on
information already in the generic OSWER materials. However, a.
decision will usually have to be made in each such case as to.
whether the generic material adequately addresses the comment, or
whether additional record support is needed. The generic
documents are meant to provide a basic level of justification for
the presumptive remedy, not to answer all possible questions or
comments about the selection of the presumptive remedy over other
possible technologies. Generally whenever the generic materials
are used to respond to a comment, a statement should preface the
response, explaining how the generic information appropriately
responds to the comment for this specific site.
Again, it is important to remember that the generic
materials are not legally binding. Thus, if a factual statement
in a generic directive is challenged in a comment, it may be
necessary to find record support for that statement. The
technical supporting material used in developing the presumptive
remedy may be a useful source of information for such purposes.
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Furthermore, the generic materials sometimes exclude certain
technologies based on assumptions about likely site conditions.
Where unusual site conditions are present, the generic OSWER
materials may actually support considering a different '
technology. Therefore, in responding to comments of this kind,
the RI and the FS analysis generally should be reviewed to
determine whether they tend to support or refute the comment.
Where the generic OSWER materials themselves are not
adequate, the supporting materials relied on in preparing them
may provide the necessary support. In other cases, some new,
site-specific technical analysis may be necessary. In any case,
EPA'.s response should be placed in the administrative record.
C. if a coriungnter supports a new technology, a site-
specif ie reaoonaa may have to be provided, and Placed
into the administrative record.
The generic materials provide a "ready to use" record
comparing the presumptive remedy with a wide range of
technologies. However, it is possible that either EPA, or other
parties, will be interested in evaluating some other technology
not previously addressed (e.g., an innovative technology).1
In that case, the generic materials do not provide the necessary
record.
If a commenter supports a new technology, a site-specific
response may have to be provided because the existing documents
do not address that issue. In such cases a decision might be
made to consider the new technology along with the recommended
technologies, although this would not always be necessary.
Deciding to consider one additional technology does not require
abandoning the entire presumptive remedy .approach. The
presumptive remedy materials can still be relied on to justify
limiting analysis'to a small number of alternatives. Whatever'
EPA's response may be, the written record of the response should
be placed in the administrative record.
D. The OSWER presumptive remedy guidances should be Kept
in the administrative record. It may fre useful to
plaea a notice in the administrative record file and in
tha administrative record file index regarding the
availability of the underlying data won which th«?
The relation between the presumptive remedy approach and the
general policy encouraging consideration of innovative
technologies is discussed in more detail on page 5 of
"Presumptive .Remedies: Policy and Procedures," September 1993
(OSWER Directive 9355.0-47FS). .
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.'•' 12
The NCP requires that the administrative record be
maintained both at the lead agency's office (or other central
location), and in a repository at or near the site. In general,
it is desirable for the repository record to be as complete as
possible, but in some cases space limitations and copying
expenses may make it necessary to limit the repository record.
In such cases, the NCP allows certain categories of materials to
be kept only in the central location (40 CFR § 300.805(a)), so
long as they are made available at the repository near the site
on request (40 CFR § 300.805(b)).
One of the categories of materials that need not be kept at
the repository near the site is "guidance documents not generated
specifically for the site at issue." 40 CFR § 300.805(a)(2). The
OSWER Directives establishing presumptive remedies would fall in
this category. Nevertheless, such materials are generally short
enough that they can be easily maintained in the local file, and
because they are so central to the remedy selection process it
may be desirable to keep them in the local file to ensure that
the public is fully informed.
.For each presumptive remedy, EPA has also developed a file
containing all the technical references, and past feasibility
studies, that were studied in developing that presumptive remedy.
One copy of the file for each presumptive remedy developed so far
has been provided to each Region. These files are generally
bulky, and would generally not be necessary for public
information purposes (or even particularly useful, because of
their highly technical nature). Accordingly, we do not recommend
that these files be physically kept in each local administrative
record file. (Since these materials simply represent support for
non-site-specific guidance, the NCP provision cited above
provides authority for that approach.) However, we do recommend
placing a notice in the local file noting that these materials
exist and are available for public review and copying. They
should also be made available locally if requested.
Maintaining a separate copy of these "backup" materials in
the site-specific administrative record file maintained at the
regional office should not be necessary. So long as the
materials are readily available, it should be sufficient to place
a notice in the index to the administrative record file (e.g., in
the preamble) indicating that they are part of the record and
where they are available.
cc: Bruce Diamond, OSRE
Steven Luftig, OERR
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\ UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
3
o
r.
WASHINGTON, D.C. 20460
SEP 261994
OFFICE OF
SOLID WASTE AND EMt c.r.;:,:
RESPONSE
MEMORANDUM
SUBJECT: Feasibility Study Analysis and Administrative Record
for Presumptive Remedies
.•'Di
FROM: David A. Bennett, Acting .•'Diryecizbi?
Hazardous Site Control Divi/§i
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Seven site categories have been identified for presumptive
remedy guidance development. The supporting documentation to the
VOCs in soils and municipal landfill sites directives are
presently being forwarded to the Regions. Additional directives
addressing woodtreater, polychlorinated biphenyls (PCBs),
groundwater, coal gasification, and grain storage sites are
currently under development and are scheduled to be completed and
distributed to the Regions early in 1995.
IMPLEMENTATION
The attached documents along with the above cited
presumptive remedies directives, are key elements of the
administrative record for VOCs in soils and municipal landfill
sites where the "presumptive remedy" approach is being used.
Under the presumptive remedy approach, the Feasibility Study (FS)
or Engineering Evaluation/Cost Analysis (EE/CA) is limited to
considering only those technologies identified by EPA as
presumptively appropriate for the specific site.
The attached documents in essence serve as a generic FS
establishing the preferred technologies and screening out all
other technologies. The documents should be placed in the
administrative record, along with the appropriate directive, at
the time.the decision is made to use the presumptive remedy .
approach.
Regional personnel involved with particular presumptive
remedies sites should familiarize themselves with all contents of
the directive and the administrative record for their site type.
A brief summary on how to use the administrative record along
with the associated directives is presented in Attachment B.
For further information, please contact Shahid Mahmud of my
staff at 703-603-8789.
Attachments
Addresses:
Superfund Regional Branch Chiefs w/ Attachments A,B
Superfund Regional Section Chiefs w/Attachments A,B
Regional Counsel Branch Chiefs w/Attachments A,B
Presumptive Remedies Regional Contacts w/ Attachments A,B
Administrative Records Contacts w/ Attachments A,B and
Administrative Record
cc: Henry Longest
George Wyeth
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ATTACHMENT A
4
PRESUMPTIVE REMEDIES ADMINISTRATIVE RECORDS CONTACTS
REGION
I
II
III
IV
V
VI
VII
VIII
IX
X
CONTACT
Margaret Meehan
Jenny Delcimento
Anna M. Butch
Debbie Jourdan
Janet Pfundheller
Nancy Yarberry
Barry Thierer
Carol Macy
Craig Cooper
Lynn Williams
PHONE
617-573-9647
212-262-8676
215-597-3037
404-347-2930
312-353-5821
214-655-6537
913-551-7515
303-294-7038
415-744-2370
206-553-2121
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ATTACHMENT B
PRESUMPTIVE REMEDY ADMINISTRATIVE RECORD CONTENTS AND GUIDE
PURPOSE
This guide is intended to assist the" U.S. Environmental
Protection Agency (EPA) Regional staff and the public in
understanding the administrative record documents and site-type
directives for supporting presumptive remedies at individual
sites. These documents and directives in essence serve as a
generic FS establishing the preferred technologies as
presumptive, and screening out all other technologies. Using
this information will potentially streamline and accelerate the
remedy selection process. In general, the administrative record
for a site using presumptive remedies will consist of site- f
specific information (e.g., technical, administrative, legal) and
the presumptive remedies administrative record components
highlighted in the section below.
CONTENTS OF ADMINISTRATIVE RECORD
This section highlights and provides a brief discussion of
the primary components of the administrative record for a site
where the presumptive remedy approach is being used. The
contents of the Record include:
I. Presumptive Remedies Directives
II. Feasibility Study Analysis Report (FSAR) and Supporting
Technical Background Documents
III. Feasibility Studies for sites supporting FSAR
IV. Records of Decision for sites supporting FSAR
V. Other Reference Documents
A general discussion on the Presumptive Remedies Directives
and the FSAR is provided below.
I. Directives:
The appropriate site-type directives (e.g., Presumptive
Remedy for CERCLA Municipal Landfill sites) together with the
General Policy and Procedure directive must be included in the
Administrative Record. The policy and procedures directive
addresses overall policy and programmatic issues associated with
presumptive remedies. The site-type directive's text and
associated tables provide information on the technologies that
were selected as presumptive remedies and provides the
justification for such a selection. Appendix A to the site-type
directive provides a statistical summary (drawn from the
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Feasibility Study Analysis for the site category) of the
technologies screened out from further consideration. Appendix B
contains a "nine criteria" analysis of the recommended technology
or technologies. (NOTE: only seven criteria are addressed,
because state and local acceptance can only be evaluated site
specifically.)
II. FS Analysis Reports
Another key component of the Administrative Record is the
FS Analysis Report for the particular category of site. The FS
Analysis Report provides information on the technologies that
were screened from further consideration in site universe of FSs
analyzed. This report in essence provides the justification for
not considering these technologies in site-specific FSs when the
presumptive remedy approach is being implemented. The report
describes each technology, and the strengths and weaknesses of
each, including factors that tend to limit each technology's
usefulness. For each technology considered, the FS Analysis
contains a conclusion explaining why that technology is not
generally suitable for such sites. Finally, each document
contains tables analyzing the technologies in terms of the remedy
selection criteria.
The conclusions in the FS Analyses often contain some
caveats because the suitability of a given technology may vary
depending on site specific conditions. While the technology may
be generally unsuitable for the particular type of site, it may
be suitable for further consideration in exceptional cases.
The information in the FS Analyses is .drawn in part from
prior feasibility studies, and partly from other sources (e.g.,
technical resource documents). In some cases, either to respond
to comments or for other reasons, users may wish to review the
underlying documentation used in developing the-FS analysis.
Finally, the appendices the FS Analysis contain useful
supporting information. Appendix A to the FS Analyses provides a
statistical summary of the rationale or basis used for screening
out the non-recommended technologies as cited in past feasibility
studies (similar to Appendix. A in directive). Appendix B
describes in greater detail the reasons given in past feasibility
studies for screening each technology out where it was excluded
at the preliminary screening phase. Appendix C summarizes the
findings -of each feasibility study analyzed as part of this
study, on a site by site basis.
III. Technical Background Documents, Feasibility Studies, Records
of Decision, and Other Reference Materials
The directives and the FS Analyses discussed above
are documents that were based on various technical literature,
site-specific FS Reports and Records of Decisions and other
reference materials. 'As such, this material is also an integral
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part of the administrative record and should be placed with the
other materials to support presumptive remedies at a particular
site.
IMPLEMENTATION
The user should be aware that both the directives and FS
analyses present statistical information on the conclusions drawn
in past feasibility studies including the number of times each
technology was rejected at the preliminary screening phase, the
number of times each was rejected at the detailed analysis phase,
and the number of times each was selected. While such
statistical analysis does not provide reasons for such decisions
(and the reasons may have differed from site to site), it can be
valuable as a reflection of the agency's past experience.
Before choosing the presumptive remedy approach, Agency
personnel should review the FS Analysis to determine whether
unusual site conditions exist that warrant further consideration
of non-presumptive remedy technologies. Additionally, the use of
this approach should be discussed early and often with the
community, state, and the potentially responsible parties (PRPs).
Further assistance on the implementation of this initiative is
available through the Headquarters and Regional Presumptive
Remedies contacts.
Additionally, the user should note that these documents are
meant to provide a basic level of justification for-the
presumptive remedy, not to answer all possible questions or
comments about the selection of the presumptive remedy. In some
cases, outside parties may submit comments supporting
technologies other than those recommended. A decision will have
to be made in each such case as to whether the material provided
here adequately addresses the comment, or whether additional
record support is needed.
For example, if a commenter contends that unusual site
conditions warrant considering a different technology, the FS
analysis should be reviewed to determine whether it adequately
addresses that argument. If a comment supports a technology not
discussed in the FS analysis at all (e.g., an innovative
technology), a site specific response will have to be provided.
In such cases a decision might be made to consider the innovative
technology along with the recommended technologies. A case-by-
case decision will have to be made based on the information
available on the technology and best engineering judgement.
Finally, if all parties have agreed to this approach, the
administrative and technical documents (e.g., Work Plan, FSs,
EE/CAs, Proposed Plans, RODs, etc.) for the site should indicate
that the site followed the presumptive remedy approach and is
supported by the documentation provided in the administrative
record. •
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}?STRIBUT1ON SHEET FOR EPA Requisition: 9-OQl?2-EPA-3A
.Print Order:
m
. S. Environmental Protection Agency
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J.S. Environmental Protection Agency
The Ardwick Industrial Plaza
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handover, MD 20784
MTN:
U.S. Environmental Protection Agency
The Ardwick Industrial Plaza
8335-8361 Arwick-Ardmorfe Road
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ATTN:
U.S. Environmental Protection Agency
The Ardwick Industrial Plaza
8335-8361 Ardwick-Ardmore Road
Landover, MD 20784
ATTN:
Copies
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ATTN:
SEND CAMERA COPY, NEGATIVES ...
U.S. Environmental Protection Agency
401 M Street, S.W., Room 6-161, (3204)
Washington, DC 20460
LINDA CREASEY
OTHER' DESTINATIONS:
NTIS
5285 Port Royal Road
Springfield, VA 22161
350 copies
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