United States
         Environmental Protection
Office of Research and
Washington, DC 20460
EPA/5402-91 013A
July 1991
         Guide for Conducting
         Treatability Studies Under
         CERCLA: Aerobic
         Remedy Screening
         Interim Guidance
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                                                              July 1991
                        REMEDY SCREENING

                       INTERIM   GUIDANCE
                          U.S. Environmental Protection Agency
                          Risk Reduction Engineering Laboratory
                           Office of Research and Development
                              Cincinnati, Ohio 45268


                        Office of Emergency and Remedial Response
                       Office of Solid Waste and Emergency Response
                              Washington, D.C. 20460
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                        The information in this document has been funded wholly or in part by the
                        U.S. Environmental Protection Agency (EPA) under contract No. 68-C8-0061,
                        Work Assignment No.  2-10, to Science Applications  International
                        Corporation (SAIC). It has been subjected to the Agency's  peer and
                        administrative reviews, and it has been approved for publication as an EPA
                        document. Mention of trade names or commercial products  does not
                        constitute endorsement or recommendation for use.
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                             Today's rapidly developing and changing technologies and industrial
                             products  and practices frequently  carry  with them  the increased
                             generation of materials that, if improperly dealt with, can threaten both
                             public health and the environment. The U. S. Environmental Protection
                             Agency (EPA) is charged by Congress with protecting the Nation's
                             land,  air,  and  water  resources.  Under a mandate of  national
                             environmental laws, the agency  strives to formulate and implement
                             actions leading to a compatible balance between human activities and
                             the ability of natural systems to support and  nurture life.  These laws
                             direct the  EPA to perform research to define our environmental
                             problems, measure the impacts, and search for solutions.

                             The Risk Reduction Engineering Laboratory (RREL) is responsible for
                             planning, implementing, and managing research, development,  and
                             demonstration  programs  to  provide an  authoritative,  defensible
                             engineering basis in support of the policies, programs, and regulations
                             of the EPA with respect to drinking water, wastewater, pesticides, toxic
                             substances,  solid  and hazardous  wastes,  and  Superfund-related
                             activities. This publication is one of the products of that research and
                             provides a vital communication link between the researcher and the
                             user community.

                             The primary purpose of this guide is to provide standard guidance for
                             designing  and  implementing  an aerobic  biodegradation  remedy
                             screening  treatability  study  in support  of  remedy  evaluation.
                             Additionally, it describes a three-tiered approach, that consists of 1)
                             remedy screening, 2) remedy selection,  and 3) remedy design, to
                             aerobic biodegradation treatability testing. It also presents a guide for
                             conducting treatability studies in a systematic and stepwise fashion for
                             determination of the  effectiveness  of aerobic biodegradation  in
                             remediating a CERCLA site. The intended  audience for this guide
                             comprises Remedial Project Managers (RPMs), Potentially Responsible
                             Parties (PRPs), contractors, and technology vendors.
                                                                   E. Timothy Oppelt, Director
                                                        Risk Reduction Engineering Laboratory
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                          Systematically conducted, well-documented treatability studies are an
                          important component of the remedial investigation/feasibility study (RI/FS)
                          process and the remedial design/remedial action (RD/RA) process under the
                          Comprehensive Environmental Response, Compensation, and Liability Act
                          (CERCLA). These studies provide valuable site-specific data necessary to
                          aid in the selection and implementation of the remedy. This manual focuses
                          on aerobic biodegradation remedy screening treatability studies conducted
                          in support of remedy evaluation that is conducted prior to the Record of
                          Decision (ROD).

                          This manual presents a standard guide for designing and implementing an
                          aerobic biodegradation remedy screening treatability  study. The manual
                          presents a description of and discusses the applicability and limitations of
                          aerobic biodegradation technologies and defines the prescreening and field
                          measurement data needed to determine if treatability testing is required. It
                          also presents an overview of the process of conducting treatability tests
                          and  the applicability of tiered treatability  testing for  evaluating aerobic
                          biodegradation technologies. The specific goals for each tier of testing are
                          defined and performance levels are presented that should be met at the
                          remedy screening level before additional tests are conducted at the next tier.
                          The elements of a treatability study work plan are also defined with detailed
                          discussions on the  design  and execution of the remedy screening
                          treatability study.

                          The manual is not intended to serve as a substitute for communication with
                          the experts and/or  regulators nor as the sole basis for the selection of
                          aerobic biodegradation as a particular remediation technology. In addition,
                          this  manual is designed to be used in conjunction with the Guide for
                          Conducting Treatability  Studies Under CERCLA, Interim  Final/18)  The
                          intended audience for this guide consists of Remedial Project Managers
                          (RPMs),  Potentially Responsible  Parties  (PRPs),   contractors,  and
                          technology vendors.
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                                    TABLE OF  CONTENTS
               DISCLAIMER 	11
               FOREWORD 	111
               ABSTRACT	iv
               FIGURES 	vi
               TABLES 	 vii
               ACKNOWLEDGEMENTS  	viu

        1.      Introduction  	1
               1.1   Background 	1
               1.2   Purpose and Scope  	1
               1.3   Intended Audience	2
               1.4   Use of This Guide	2

        2.      Technology Description and Preliminary Screening  	3
               2.1   Technology Description 	3
               2.2   Preliminary Screening and Technology Limitations 	 8

        3.      The Use of Treatability Studies in Remedy Evaluation  	13
               3.1   Process of Treatability Testing in Evaluating a Remedy 	13
               3.2   Application of Treatability Tests	15
       4.      Remedy Screening Treatability Study Work Plan	19
               4.1    Test Goals  	19
               4.2    Experimental Design	20
               4.3    Equipment and Materials  	22
               4.4    Sampling and Analysis 	23
               4.5    Data Analysis and Interpretation 	24
               4.6    Reports	24
               4.7    Schedule  	24
               4.8    Management and Staffing	  25
               4.9    Budget 	25

       5.      Sampling and Analysis Plan 	  27
               5.1    Field Sampling Plan	27
               5.2    Quality Assurance Project Plan  	  28

       6.      Treatability Data Interpretation  	31

       7.      References 	35
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       Number                                                                                       Page

       2-1.     In Situ Bioremediation of Groundwater	4

       2-2.     Solid-Phase Bioremediation  	5

       2-3.     Above-Ground Slurry-Phase Bioremediation  	6

       2-4.     Slurry-Phase Bioremediation in Existing Lagoon  	6

       2-5.     Soil Heap Bioremediation 	7

       2-6.     Open Windrow Composting	7

       3-1.     Flow Diagram of the Tiered Approach  	14

       3-2.     TheRoleof Treatability Studies in the RI/FS and RD/RA Process 	15

       4-1.     Example Project Schedule for a Treatability Study 	25

       4-2.     Organization Chart 	26

       6-1.     Plot of Hydrocarbon Concentration versus Time  	32
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       Number                                                                                      Page

       4-1.     Suggested Organization of Aerobic Biodegradation Remedy Screening Treatability Study Work Plan .... 19

       4-2.     Commonly Used Analytical Chemistry Methods for Soil Parameters 	23

       4-3.     Major Cost Elements Associated With Aerobic Biological Remedy Screening Treatability Studies	26

       5-1.     Suggested Organization of the Sampling and Analysis Plan 	28

       6-1.     Hydrocarbon Concentration (ppm) Versus Time  	31
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                         This guide was prepared for the U.S. Environmental Protection Agency,
                         Office of Research and Development (ORD), Risk Reduction Engineering
                         Laboratory  (RREL),  Cincinnati,  Ohio,  by  Science  Applications
                         International   Corporation  (SAIC)   along  with  its  subcontractor,
                         Environmental Resource Management, Inc. (ERM), under Contract No.
                         68-C8-0061. Mr.  David Smith served as the  EPA Technical Project
                         Monitor. Jim Rawe served  as the primary technical author and SAIC's
                         Work Assignment Manager. Mr. Derek Ross served as a technical expert
                         and was ERM's Subcontractor Manager. The project team included Tom
                         Wagner, George Wahl, and Joe Tillman of SAIC; Jonathan Moyer of
                         ERM; and Mike Martinson of Delta Environmental Consultants, Inc.
                         Clyde Dial served as SAICs Senior Reviewer, and Natalie Barnes served
                         as the Technical Editor. The authors are especially grateful to Mr. Steve
                         Safferman of EPA, RREL, who has contributed significantly by serving as
                         a technical consultant during the development of this document.

                         Ms. Robin M. Anderson of  the Office  of Emergency and  Remedial
                         Response (OERR) has been the inspiration  and  motivation for  the
                         development of this document. The authors want to give special thanks to
                         Fran Kremer, EPA, CERI; Joe Healy, EPA, Region IX; Peter Chapman,
                         EPA,  ORD;   Carol  Litchfield,  Environment American,  Inc.;  Dick
                         Woodward, ENSR, Inc; Paul Flathman, O.H. Materials Corporation; John
                         R Smith,  ReTeC, Inc.; and Ronald Crawford,  University of Idaho, for
                         their continued involvement in the development of this document.

                         The following other Agency and contractor personnel have contributed
                         their time and comments by participating in the expert workshop and/or
                         peer reviewing the draft document:

                         Ron Lewis               EPA, RREL
                         John Glaser              EPA, RREL
                         RichHaugland           EPA, RREL
                         Henry Tabak             EPA, RREL
                         BenBlaney              EPA, RREL
                         Ed Bates                EPA, RREL
                         Pat McDonald           EPA, Region VII
                         Chris Rascher           EPA, Region I
                         Linda Fiedler             EPA, Technical Information Officer
                         John Rodgers            EPA, ERL - Athens
                         Maureen Danna          ABB Environmental
                         Kate Devine             Applied Biotreatment Association
                         Dick Bleam              Bioscience Management
                         Durell Dobbins          Biotrol
                         Tom Chresand           Biotrol
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                         Keith Piontek
                         Tom Simpkin
                         Robert Finn
                         William Mahaffey
                         Ralph Baker
                         Barry Scott
                         John Cookson
                         Al Rozich
                         Gary Boettcher
                         Suxuan Huang
                         Ralph Portier
                         Anthony Bulich
                         Todd Stevens
                         Ralph Guttman
                         Phillip Launt
                         Hans Stroo
                         David Nutini
                         Rick Bartha
                         Larry N. Britton
                         Robert Irvine
                         James Early
                         Jim Spain
                         John A. Dickerson
                         Daniel Shelton
                         Brian Schepart
Cornell University
Ecova Corporation
ENSR, Inc.
ENSR, Inc.
General Physics Corporation
Geraghty & Miller, Inc.
Keystone Environmental Resources
Louisiana State University
Pacific Northwest Laboratories
Polybac Corporation
Resource Appraisals & Management
ReTeC, Inc.
RNK Environmental, Inc.
Rutgers University
Texas Research Institute, Inc.
University of Notre Dame
University of Notre Dame
U.S. Air Force
Wastestream Technology
                          The document was also reviewed by the Office of Waste Programs
                          Enforcement and the Technology Innovation Office. We sincerely hope we
                          have not overlooked anyone who participated in the development of this
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                                                 SECTION  1
        1.1    BACKGROUND

        Section 121(b) of the  Comprehensive  Environmental
        Response, Compensation and Liability Act (CERCLA)
        mandates the Environmental Protection Agency (EPA) to
        select remedies that "utilize permanent solutions  and
        alternative treatment technologies or resource recovery
        technologies to the maximum extent practicable" and to
        prefer  remedial  actions  in  which  treatment   that
        "permanently  and  significantly reduces the volume,
        toxicity  or  mobility  of the  hazardous  substances,
        pollutants, and contaminants is a principal element."
        Treatability studies provide data to support treatment
        technology selection and remedy implementation  and
        should be performed  as soon as it is evident that
        insufficient information is available to ensure the quality
        of the decision. Conducting treatability studies early in
        the   remedial  investigation/feasibility  study  (RI/FS)
        process should reduce  uncertainties associated with
        selecting the remedy and provide a sounder basis for the
        Record of Decision (ROD).  Regional planning should
        factorin the time and resources required for these studies.

        Treatability studies conducted during the RI/FS phase
        indicate whether  a given technology  can meet  the
        expected cleanup goals for the site, whereas treatability
        studies conducted during the remedial design/remedial
        action (RD/RA) phaseestablish the design and operating
        parameters for optimization of technology performance.
        Although the purpose and scope of these studies differ,
        they complement one another (i.e., information obtained
        in support of  remedy  selection may  also  be  used to
        support the remedy design).(26:i

        This document refers to three levels or tiers of treatability
        studies: remedy screening, remedy selection, and remedy
        design. Three tiers of treatability studies are also defined
        in the Guide for Conducting Treatability Studies Under
        CERCLA, Interim Final  (18), referred to as the "generic
        guide" hereafter in this document. The generic guide
        refers to the three treatability study tiers, based largely on
        the  scale of test equipment, as laboratory  screening,
        bench-scale testing, and pilot-scale testing.  Laboratory
        screening is typically used to screen potential remedial
        technologies and is equiva-
lent to remedy screening. Bench-scale testing is typically
used for remedy selection, but may fall short of providing
enough information for remedy selection. Bench-scale
studies can, in some cases, provide enough information
forfull-scale design. Pilot-scale studies are normally used
for remedial design, but may be required for remedy
selection in some cases. Because of the overlap between
these tiers, and because of differences in the applicability
of each tier to different technologies, the  functional
description of treatability  study tiers  (i.e.,  remedy
screening, remedy selection, and remedy design) has been
chosen for this document.

Some or all of the levels of treatability study testing may
be needed on a case-by-case basis. The need for and the
level of  treatability  testing required  are  managerial
decisions in which the time and cost necessary to perform
the testing are balanced against the risks inherent in the
decision  (e.g., selection of an inappropriate treatment
alternative). These decisions are based on the quantity
and quality of data available and on other decision factors
(e.g., State and community acceptance of the remedy and
experience with the technology at other sites). The use of
treatability studies  in remedy selection is  discussed
further in Section 3  of this document.


This  guide is designed to ensure a credible approach is
taken to evaluate whether aerobic biodegradation should
be considered for site remediation. This guide discusses
only the remedy  screening level. Remedy screening
studies are designed to provide a quick and relatively
inexpensive indication of whether biological degradation
is  a  potentially viable remedial technology. Remedy
selection studies will  also  be  required to determine if
bioremediation is a viable treatment alternative for a site.
The remedy screening evaluation should:

      •    Provide  a  preliminary  indication  that
           reductions in contaminant concentration are
           due  to  biodegradation  and  not abiotic
           processes  such as  photo  decomposition,
           volatilization, or adsorption, and
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              •    Produce the design information required for
                   the next level of testing, should the remedy
                   screening evaluation be successful.

        The Aerobic Biological Remedy Screening Study should
        not be the only level of treatability study performed
        before final remedy selection.


        This document is intended for use by Remedial Project
        Managers  (RPMs),  Potentially  Responsible Parties
        (PRPs),   consultants, contractors,  and technology
        vendors.  Each  has  a different role  in  conducting
        treatability  studies  under  CERCLA.   Specific
        responsibilities for each can be  found in the generic

        1.4   USE OF THIS GUIDE

        This guide is organized into seven sections, which reflect
        the basic information required to perform treatability
        studies during the RI/FS process. Section 1 provides
        background information on the role of treatability studies
        in the RI/FS process, describes the purpose and scope of
        the guide,  and outlines the intended  audience for the
        guide. Section 2 describes the different types of aerobic
        bioremediation  processes currently   available  and
        discusses how to conduct a preliminary screening to
        determine if biological treatment  is  a potentially  viable
        remediation technology. Section 3 provides an overview
        of the different levels of treatability testing and discusses
        how to determine the need for treatability studies. Section
        4  provides an  overview of the  remedy  screening
        treatability study, describes the contents of a typical work
        plan, and dis-
cusses the major issues that need to be considered when
conducting a treatability study. Section 5 discusses the
Sampling and Analysis Plan, including the Field Sampling
and Quality Assurance Project Plans. Section 6 explains
how to interpret the data  produced  from a remedy
screening  treatability study  and  how to determine if
further remedy selection studies are justified. Section 7
contains the references.

This guide, along with guides being developed for other
technologies, is intended to be used as a companion
document to the generic guide.(18) In an effort to avoid
redundancy, supporting information  in  other readily
available  guidance documents is not repeated in this

This document was reviewed by representatives from
EPA's  Office  of Emergency and Remedial  Response
(OERR), Office of Research  and  Development (ORD),
Office  of Waste Programs Enforcement, Technology
Innovation Office, and Regional offices, as well as by a
number of contractors and  academic personnel. The
constructive comments received from this peer review
process  have  been  integrated  and/or  addressed
throughout this guide.

As   treatability  study  experience  is gained,  EPA
anticipates further comment and possible future revisions
to the  document.  For this  reason, EPA  encourages
constructive comments from outside sources. Comments
should be directed to:

        Mr. David Smith
        U. S. Environmental Protection Agency
        Office of Research and Development
        Risk Reduction Engineering Laboratory
        26 W. Martin Luther King Drive
        Cincinnati, Ohio 45268
        (513) 569-7957
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                                               SECTION  2
                          TECHNOLOGY DESCRIPTION  AND
                                 PRELIMINARY SCREENING
        This section describes the various full-scale aerobic
        biodegradation technologies currently available and
        discusses the information necessary  to screen the
        technology prior to commitment to a treatability test
        program. Subsection 2.1 describes several full-scale
        aerobic biodegradation systems that potentially can be
        used at Superfund sites. Subsection 2.2 discusses the
        literature and data base searches required, the technical
        assistance  available, and the review of field data
        required to prescreen these technologies. Technology
        limitations are also reviewed in this subsection.


        Bioremediation generally refers to the breakdown of
        organic compounds (contaminants) by microorganisms.
        In situ, solid-phase, slurry-phase, soil-heaping, and
        composting biological  treatment  techniques  are
        available  for  the  remediation  of  contaminated
        soils.(13)(23:) Aerobic biodegradation can be used as the
        only treatment technology at a site or along with other
        technologies in  a treatment  train. Use of aerobic
        biodegradation, especially in situ, has been very limited
        at CERCLA sites. However, the technology shows
        promise for degrading, immobilizing, or transforming a
        large number of organic compounds commonly found
        at  CERCLA sites  to environmentally acceptable

        As of fiscal year  1989, biodegradation has  been
        selected  as a component of  the remedy  for 22
        Superfund sites having groundwater, soils, sludges, or
        sediments contaminated with various volatile organics;
        phenols; creosotes;polynucleararomatichydrocarbons
        (PAHs);  and benzene,  toluene,  ethyl benzene, and
        xylene (BTEX) compounds.1-22-1

        Information on the technology applicability, the latest
        performance data, the status of the technology, and
        sources for further information is provided in a series of
        engineering bulletins being prepared by the EPA Risk
        Reduction  Engineering  Laboratory  (RREL) in
        Cincinnati, Ohio.(16)(17)
2.1.1   In Situ Bioremediation

In situ bioremediation involves enhancing the microbial
degradation of contaminants in subsurface soil and
waterwithout excavation of the contaminated soil. The
technology usually  involves  enhancing  natural
biodegradation processes by adding nutrients, oxygen
(if the process is aerobic), and  in  some cases,
microorganisms  to  stimulate the biodegradation of
contaminants. Moisture control  may be required to
optimize biodegradation. If oxygen is the rate-limiting
parameter, oxygen  sources such as air,  highpurity
oxygen, or hydrogen peroxide  are usually  used to
increase  the  amount  of  oxygen  available for
biodegradation.  Laboratory  studies  indicate the
addition of methane or other substrates may aid in the
co-metabolic biodegradation of low molecular weight
chlorinated organics. Recent evidence has shown that
anaerobic processes that use nitrate as a terminal
electron acceptor may be effective for the in situ
treatment of benzene, toluene,  xylenes,  and  some

In situ bioremediation is often used in conjunction with
a groundwater-pumping and soil-flushing system to
circulate nutrients and oxygen through a contaminated
aquifer and associated  soils. The  process  usually
involves introducing aerated, nutrient-enriched water
into the contaminated zone through a series of inj ection
wells or infiltration trenches and recovering the water
down gradient. Watersoluble contaminants are flushed
out of the soil; less soluble contaminants remain in the
soil and are biodegraded. The recovered water can then
be reintroduced or disposed of on the surface (Figure
2-1). Depending on the concentration of water-soluble
contaminants  in the  recovered water,  additional
treatment may be required  before the water can be
disposed of or recycled to the soil treatment system.

In situ bioremediation has primarily been used for the
treatment  of  saturated  soils;  however,   in  a few
instances, the technology  has  been used  to treat
unsaturated soils.  The in situ bioremediation of
unsaturated soils has typi-
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                   Injection Wells

                                                                Vadose Zone
                                           Groundwater Flow Direction
                                                    •> '  ..' .  i .  *". ..... .'.;•. '... ..... i',  1   ' .• '
                                                         .             . .. .....
                                                  L,QVV Perm? ability, Bedrock -
                             J	L
                                 Figure 2-1.  In situ bioremediation of groundwater.
        cally  been  limited  to  fairly  shallow  depths  over
        groundwater that is already contaminated. The treatment
        of unsaturated soils is difficult to control and relies on the
        use   of  percolation   techniques  to  enhance
        nutrient-adjusted water and vacuum extraction techniques
        to enhance air exchange in the soil matrix.

        In situ  bioremediation  treats  contaminants  in-place,
        eliminating the need for soil excavation and limiting the
        release of volatiles into the air. Consequently, the risks
        and costs associated with materials handling are reduced
        or eliminated. Furthermore, in situ bioremediation has the
        potential to clean up the source material responsible for
        the groundwater contamination.

        2.1.2   Solid-Phase Bioremediation

        Solid-phasebioremediation (sometimes referred to as land
        treatment) is a process that treats soils in an above-grade
        treatment system using conventional soil management
        practices  to  enhance   microbial   degradation   of
        contaminants. Solid-phase  bioremediation   can   be
        designed  using  shallow "tanks" to  meet  land-ban
                                           Solid-phase bioremediation at CERCLA sites usually
                                           involves placing excavated soil in an above-grade soil
                                           treatment area. If required, nutrients and microorganisms
                                           are added to the soil, which is tilled at regular intervals to
                                           optimize  aeration  and  contact  between  the
                                           microorganisms  and  the  contaminants.  During  the
                                           operation of a solid-phase bioremediation system, pH,
                                           nutrient  concentrations,  and moisture content  are
                                           maintained within ranges conducive to microbial activity
                                           (Figure 2-2). In some cases, the contaminated soil has to
                                           be mixed with clean soil to reduce the concentration of
                                           contaminants to levels that do not inhibit microbial
                                           activity. Solid-phase treatment systems can be modified
                                           to contain and treat soil leachate by adding underdrain
                                           and liquid treatment system. Volatile organic compounds
                                           (VOCs) can be contained by adding an optional cover.
                                           Conventional VOC treatment can be added as part of a
                                           treatment train.

                                           A variety of processes influence the fate of contaminants
                                           in solid-phase treatment systems. These include physical
                                           and chemical processes  (such as leaching, adsorption,
                                           desorption,photodecomposition, oxidation, volatilization,
                                           and  hydrolysis)   and   biodegradation.   The
                                           physical,  chemical,   and  biological   properties
                                           of  the  contaminants   and  soil  interact   with
                                           site-specific  variables  to  influence  the fate  of
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                 Soil Screening
                     Leachate Collection System
                                      Figure 2-2. Solid-phase bioremediation.
        the contaminants. The contaminants are degraded,
        immobilized,  or  transformed  to  environmentally
        acceptable components. (6)

        Decomposition and immobilization of the contaminants
        occurwithin both the zone of incorporation, usually the
        top 15 to 30 centimeters, and the underlying layers. The
        zone of incorporation and the underlying soils, where
        additional  treatment  and  immobilization   of  the
        contaminants occurs, are  referred to as the treatment
        zone. The treatment zone depth may be as much as 1.5
        meters. Most of the transformations, immobilization,
        and biodegradation occur  in the zone of incorporation.

        2.1.3   Slurry-Phase Bioremediation
                (Liquid/Solids Treatment)

        In slurry-phasebioremediation, excavatedcontaminated
        soil  is  typically  placed  in an  on-site,  stirred-tank
        reactor(s) where the soil is combined with water to form
        a slurry. The solids content of the slurry depends on
        the type  of  soil, the type of mixing and  aeration
        equipment available,  and the rates of contaminant
        removal that need to be
achieved.  The water used in  the  process  can be
contaminated surface or ground water, thus facilitating
the simultaneous treatment of contaminated soil and
water. If required, nutrients and microorganisms are
added to the slurry, which is then aerated and agitated
to optimize contact between  the  microorganisms,
nutrients, and oxygen so that efficient biodegradation
of the contaminants can occur. The process can be
operated in either a batch or a continuous mode (Figure

As with solid-phase bioremediation, the process can be
designed  to  contain and treat  volatile  organic
compounds. Slurry-phase bioremediation systems can
be used to treat sludges and sediments in existing
lagoons and impoundments, thus eliminating the need
for soil excavation (Figure 2-4). An impermeable layer
should be present under the slurry-phase system to
prevent contaminant  migration.

2.1.4   Soil Heaping

Soil heap bioremediation involves piling contaminated
soil in heaps of several meters in height. Aeration is
usually  provided by pulling a  vacuum  through the
heap. Simple
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                   Soil Screening
                              Water Recycle
                                                                              "  ft'1
     Slurry Bioreactors
                            Figure 2-3. Above-ground slurry-phase bioremediation.
                          Figure 2-4. Slurry-phase bioremediation in existing lagoon.
       irrigation techniques are generally used to maintain
       moisture content, pH and nutrient concentrations within
       ranges conducive to the biodegradation of contaminants.
       The system can be designed to control the release of
       volatile organic compounds by passing the exhaust from
       the vacuum through activated carbon (Figure 2-5).
 2.1.5  Composting

 Composting involves the storage of biodegradable waste
 with a bulking agent (e.g., chopped hay or wood chips).
 The structurally firm bulking agent can be biodegradable,
 but need not be so. Typically, two parts bulking agent are
 mixed with one part contaminated soil to improve the soil
 permeability. Adequate aeration, optimum temperature,
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                                    Visqueen Cover
                  Soil       Nutrients
                    \       Microorganisms
                                                      Side View       Plastic Piping
                                                                       (compatible with contaminants)
                                                       Top View
                                       Figure 2-5. Soil heap bioremediation.
        moisture and nutrient contents, and the presence of an
        appropriate microbial  population  are  necessary to
        enhance the decomposition of organic compounds. The
        biodegradation process may  be thermophilic. If so,
        microorganisms that occur naturally  in the decaying
        organic matter biodegrade the contaminants of concern.
        However, the elevated temperatures associated with
        thermophilic bio-
degradation may limit the  activity of indigenous and
exogenous organisms.

The three basic types of composting are open windrow
systems, static windrow systems, and in-vessel (reactor)
systems. In the open windrow system, the compost is
stacked into elongated piles (Figure 2-6). Aeration is
                                      Figure 2-6. Open windrow compositing.
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        accomplished by tearing down and rebuilding the piles. In
        the static windrow system piles of compost are aerated by
        a forced air system (e.g., the piles are built on top of a grid
        of perforated  pipes).  The in-vessel system  involves
        placing the compost into a closed reactor. Aeration is
        accomplished by tumbling, stirring, and forced aeration.


        As mentioned in Section 1, the determination of the need
        for and the appropriate level of treatability studies
        required depends on the literature information available
        on the technology, expert technical judgment,  and site-
        specific factors. The first two elements -  the literature
        search and expert consultation  -   are  critical  in
        determining if adequate data are available or whether a
        treatability  study is needed to provide those data. The
        data and information  on which this decision  is made
        should be documented.

        2.2.1   Literature/Data Base  Review

        Several reports and electronic data bases exist that should
        be consulted  to  assist in planning and conducting
        treatability  studies as well  as  to  help prescreen
        bioremediation for use at a specific site. Existing reports

            •   Guide for Conducting Treatability Studies Under
                CERCLA, Interim Final. U.S. Environmental
                Protection Agency, Office of Research and
                Development  and Office of Emergency and
                Remedial  Response,  Washington,  D.C.
                EPA/540/2-89/058, December 1989.

            •   Guidance  for   Conducting   Remedial
                Investigations  and Feasibility Studies Under
                CERCLA, Interim Final.  U.S. Environmental
                Protection Agency, Office of Emergency and
                Remedial  Response,  Washington,  D.C.
                EPA/540/G-89/004, October 1988.

            •   Superfund Treatability ClearinghouseAbstracts.
                U.S. Environmental Protection Agency, Officeof
                Emergency  and Remedial   Response,
                Washington,  D.C. EPA/540/2-89/001,  March

            •   The  Superfund  Innovative  Technology
                Evaluation Program:  Technology Profiles. U.S.
                Environ- mental Protection Agency, Office of
                Solid  Waste and Emergency Response and
                Office of Research
        and Development, Washington, D.C.
        EPA/540/5-90/006, November 1990.

    •   Summary   of   Treatment   Technology
        Effectiveness  for Contaminated  Soil.  U.S.
        Environmental Protection Agency, Office of
        Emergency   and  Remedial   Response,
        Washington, D.C., 1989 (in press).

    •   Technology Screening Guide for Treatment of
        CERCLA Soils and Sludges. U.S. Environmental
        Protection Agency. EPA/540/2-88/004,1988.

Currently, RREL in Cincinnati is expanding its Superfund
Treatability Data Base. This data base will contain data
from all treatability studies conducted under CERCLA. A
repository fortreatability study reports will be maintained
at RREL in Cincinnati. The contact for this data base is
Glenn Shaul at (513) 569-7408.

ORD headquarters maintains the Alternative Treatment
Technology  Information  Center   (ATTIC),   a
comprehensive, automated information retrieval system
that  integrates hazardous waste data  into a unified,
searchable resource. The intent of ATTIC is to provide
the user community  with technical data and information
on available alternative treatment technologies and to
serve as an initial decision support system. Since ATTIC
functions  as a focal point for users, it facilitates  the
sharing of information within the user community and
creates  an  effective  network  of  individuals  and
organizations  involved  in  hazardous waste   site

The information contained in ATTIC consists of a wide
variety of data  obtained from Federal and state agencies.
The core of the ATTIC system is the ATTIC Data Base,
which contains abstracts and executive summaries from
over 1200 technical documents and reports. Information
in the ATTIC  Data Base has been obtained from  the
following sources:

    •   The   Superfund   Innovative  Technology
        Evaluation (SITE) Program

    •   California Summary of Treatment Technology
        Demonstration Projects

    •   Data Collected for the Summary of Treatment
        Technology Effectiveness for Contaminated Soil

        North  Atlantic  Treaty Organization  (NATO)
        International Data

    •   Innovative Technologies Program Data
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            •  Removal Sites Technologies Data

            •  Resource Conservation and Recovery Act
               (RCRA) Delisting Actions

            •  USATHAMA Installation Restoration and
               Hazardous Waste Control Technologies

            •  Records of Decision (from 1988 on)

            •  Treatability Studies

            •  Superfund Treatability Data Base (also available
               through ATTIC).

        In addition, the ATTIC system contains a  number of
        resident data bases that have been previously developed,
        as well as access to on-line commercial data bases. For
        more information, contact the ATTIC System Operator at

        The Office of Solid Waste and Emergency Response
        (OSWER) maintains an Electronic Bulletin Board System
        (BBS)  as  a  tool  for communicating  ideas   and
        disseminating information and as a gateway for other
        Office  of Solid  Waste  (OSW)  electronic  data bases.
        Currently, the BBS has eight  different components,
        including news and mail services and conferences and
        publications on specific technical areas. The contact is
        James Cummings at (202) 382-4686.

        The  RREL  in  Edison,  New  Jersey, contains  a
        Computerized On-Line Information Sy stem (COLIS), which
        consolidates several computerized data bases by RREL in
        Cincinnati and Edison. COLIS contains three files: Case
        Histories, Library  Search,  and   SITE Applications
        Analyses Reports  (AARs).  The  Case Histories  file
        contains historical information obtained from corrective
        actions implemented at Superfund sites. The Library
        Search system provides access to special collections and
        research information on many RREL programs. The SITE
        AARs  file  provides  actual cost  and performance
        information. The contact is Pacita Tibay at (201) 906-6871.

        2.2.2  Technical Assistance

        The Technical Support  Project (TSP) is made up of six
        Technical Support Centers and two Technical  Support
        Forums. It is a joint service of OSWER, ORD, and the
        Regions. The  TSP  offers direct site-specific technical
        assistance to On-Scene  Coordinators (OSCs) and RPMs
        and develops technology workshops, issue papers, and
        other information for Regional staff. The TSP:
    •  Reviews contractor work plans, evaluates
       remedial alternatives, reviews RI/FS, assists in
       selection and design  of final remedy

    •  Offers modeling assistance and data analysis
       and interpretation

    •  Assists in developing and evaluating sampling

    •  Conducts field studies (soil gas, hydrogeology,
       site characterization)

    •  Develops technical workshops and training,
       issues papers on groundwater topics, and
       generic protocols

    •  Assists in performance of treatability studies.

The  following  support centers  provide  technical
information and advice related to aerobic biodegradation
and treatability studies:

1.   Ground-Water  Fate  and  Transport  Technical
    Support Center
       Robert S. Kerr Environmental Research
       Laboratory (RSKERL), Ada, OK
       Contact: Don Draper
               FTS 743-2202 or (405) 332-8800

RSKERL in Ada, Oklahoma,  is EPA's center for fate and
transport research, focusing  its efforts on transport and
fate of contaminants in the vadose and saturated zones of
the subsurface, methodologies relevant to protection and
restoration of groundwater  quality, and  evaluation of
subsurface processes  for the treatment  of hazardous
waste. The Center provides technical assistance such as
evaluating  remedial alternatives; reviewing RI/FS and
RD/RA work plans; and providing technical information
and advice.

2.   Engineering Technical Support Center
    Risk Reduction Engineering  Laboratory (RREL),
    Cincinnati, OH
    Contact: Ben Blaney
        FTS 648-7406 or (513) 569-7406

The  Engineering Technical  Support Center (ETSC) is
sponsored by OSWER but operated by RREL. The Center
handles site-specific remediation engineering problems.
Access to this support Center mustbe  obtained through
the EPA remedial project manager.
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        REEL  offers expertise in contaminant source control
        structures; materials  handling and  decontamination;
        treatment of soils, sludges and sediments; and treatment
        of  aqueous and  organic  liquids.  The following  are
        examples of the technical assistance that can be obtained
        through ETSC:

        •   Screening of treatment alternatives

        •   Review of the treatability aspects of RI/F S

        •   Review of RI/FS treatability study Work Plans and
            final reports

        •   Oversight of RI/FS treatability studies

        •   Evaluation of alternative remedies

        •   Assistance with studies of innovative technologies

        •   Assistance in full-scale design and start-up

        2.2.3  Prescreening Characteristics

        The major parameter that influences the feasibility of
        using biological processes is the biodegradability of the
        compounds of concern. Prior to conducting a remedy
        screening of bioremediation it is important to confirm that
        the compounds  of concern are  indeed  amenable  to
        biological treatment.

        As discussed in  Subsection 2.2.1, a literature search
        should be performed for the compounds or wastes of
        interest, including compounds of similar structure. The
        key question to be answered is whether any evidence of
biodegradation of these compounds or wastes exists. The
literature review should not be limited to a biodegradation
technology  that  has been chosen for  preliminary
consideration. Evidence of aerobic biodegradation under
conditions not likely to be applicable to a site should not
be eliminated from consideration. Likewise, a literature
search indicating that biodegradation is unlikely should
not  automatically   eliminate  aerobic  biological
technologies  from consideration. On the other hand,
previous studies indicating that pure chemicals will be
degraded  must  be viewed with  caution.  Chemical
interactions or inhibitory effects of contaminants can alter
the biodegradability of chemicals in complex mixtures
frequently found at Superfund sites.

The literature search should also investigate the chemical
and  physical  properties of the  contaminants.  The
volatility of the contaminants is one of the most important
physical characteristics. Knowledge of the contaminant
volatility is important in the prescreening step since
highly volatile contaminants may be difficult to degrade,
especially  in stirred or highly aerated reactors because
they volatilize before thay can be degraded.

There is no steadfast rule that specifies when to proceed
with remedy screening and when to eliminate aerobic
biodegradation as a treatment technology based  on  a
preliminary screening analysis. An analysis of the existing
literature coupled with  the  site characterization  will
provide  the information  required to make an educated
decision. However, when in doubt,  a remedy screening
study is recommended. Several guidance documents are
available to aid in determining the key contaminant and
matrix characteristics  which are needed  to prescreen
various technologies.1-15-"-18^23'Example 1 is  a hypothetical
literature search provided  to  illustrate  some  of the
complexities of this analysis.
                                                       Example 1.

              A site is contaminated with an organic solvent. The contamination extends to a depth of 50 feet below
              the surface. Considering the overall extent of the  zone of contamination,  removal  of the soil for
              above-ground treatment is not considered as a remediation technology for the site. However, a review
              of the literature reveals only two previous studies on the biodegradation of the solvent of concern.

              The first study showed that greater than 95 percent of the semi-volatile solvent could be removed over
              a 3-week period with a slurry-phase biological treatment process utilizing  naturally occurring soil
              microorganisms. The study made no attempt to measure losses due to volatilization.  However, a
              12-percentloss of solvent was measured in a control reactorwhere biodegradation was inhibited with
              mercuric chloride to account for abiotic losses (chemical degradation, sorption and volatilization).
              Therefore, 83 percent of the contaminant was removed by biotic processes
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                  (biodegradation)  during  the study period.  Even though  above-ground  slurry-phase
                  treatment is not appropriate for the site of concern, the previous study did show that,
                  under appropriate conditions, naturally occurring microorganisms can biodegrade a large
                  percentage of the solvent.

                  The second study was a remedy design (pilot-scale) demonstration that showed that
                  after 5 months the solvent could not be biodegraded in situ, even with the addition of
                  nutrients and oxygen. This study indicates that in situ biodegradation of the solvent is
                  not likely to occur.

                  At first glance, the literature review appears to rule out the use of in situ bioremediation
                  to clean up the solvent-contaminated subsurface soil. However, caution should be used
                  in excluding aerobic biodegradation on the basis of one study. The intent of the remedy
                  screening treatability study is to assess the potential of a technology at a minimum
                  cost.  If there is  any reason to believe aerobic biodegradation has  the potential to
                  remediate the contaminant of interest, remedy screening studies should be considered.

                  The first study indicated that biodegradation is potentially a viable technology. However,
                  successful  biodegradation  in  a slurry bioreactor is not an assurance that in situ
                  biodegradation will occur. The second study tends to indicate that in situ bioremediation
                  of this contaminant will not be possible. However,  a simple change in pH or nutrient
                  composition, the  removal of some inhibitory substance, or the use of a different microbial
                  population could  result in successful in situ bioremediation of the solvent.  In this case,
                  the RPM decided that a quick remedy screening study was warranted to assess the
                  feasibility of using biological treatment at the site of concern.
        Examples of classes of compounds that are readily
        amenable to bioremediation are petroleum hydrocarbons
        such as gasoline and diesel fuel; wood-treating wastes
        such as creosote and pentachlorophenol; solvents such
        as  acetone,  ketones,  and  alcohols;   and  aromatic
        compounds such as benzene, toluene, xylenes, and
        phenols. Several documents and review  articles that
        present detailed information on the  biodegradability of
        compounds   are  listed   in  the  reference
        section.(3)(8)(11)(12)(20)(23) However, discretion should be
        exercised when  using  these  reference materials, as
        microorganisms  that   can biodegrade  compounds
        traditionally  considered  non-biodegradable   are
        continually  being discovered through ongoing research
        and development efforts.
        2.2.4  Technology Limitations

        Many  factors  impact  the  feasibility  of  aerobic
        biodegradation  in  addition  to  the  inherent
        biodegradability as measured in the screening test. These
        factors should be addressed prior to the selection of
        aerobic biodegradation and prior to the investment of time
        and funds in further testing. Some of these factors  are
        discussed in this section. A detailed discussion is beyond
the scope of this document. The reader should consult
references 15 through 18, and others, for more information
on these factors.

The concentrations of contaminants and pH are examples
of parameters that influence  the feasibility  of using
biological treatment processes. However, it should be
noted that treatment  systems can be  designed  and
engineered  to  accommodate  wastes  with  high
contaminant concentrations and extreme pH values. For
example, diesel-contaminated soil with a pH of 2 can be
treated biologically. However, a neutralization step is
required to adjust the pH to within a range conducive to
biological  treatment  (generally  6.5  to  8.5)  prior to
bioremediation.  Likewise, if  the  concentrations of
contaminants are high enough to inhibit microbiological
activity, a dilution step can be introduced to reduce the
concentrations to within ranges conducive to biological
treatment. For example, solid-phase treatment systems are
generally operated  at a maximum of 5  to  10 percent
extractable oil and grease. These concentrations of oil and
grease can be achieved by mixing less contaminated soil
with heavily  oiled soils  in  above-ground processes.
Metals may be leached or complexed to reduce microbial
toxicity  and improve  the potential for contaminant
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        Non-uniform particle size distribution, the type of soil, and
        the permeability of the soil to air and water are the soil
        characteristics that most affect the aerobic biodegradation
        process, especially in situ. Organic contaminants tend to
        be adsorbed to fine particles such as silts and clays.
        Therefore, non-uniform particle size distribution can cause
        inconsistent degradation rates for in situ processes due
        to variations in biological activity associated with variable
        contaminant  composition   and  concentrations.  The
        presence of significant quantities of decaying organic
        matter (humus, peat, etc.) may cause high oxygen uptake
        rates, depleting available oxygen supplies in the soil.
        Materials handling and mixing in above-ground processes
        are affected by  particle size  distribution  and  debris
        present in the soil.

        Low soil permeability can hinder the flow of air, moisture,
        and  nutrients, limiting the effectiveness of  in  situ
        processes. Moisture, oxygen, and nutrient content in soils
        and  soil pH and temperature affect in situ  microbial
        activity. Generally, such characteristics can be controlled
        or modified through engineering practices.

        The presence of an active microbial population with the
        capability to degrade the  contaminants of interest is
        essential to the success of in situ processes. The activity
concentration of soil microbes  can be stimulated by
moisture,  nutrient, and oxygen  additions.  Selected
microorganisms can be  added to enhance the natural
population. However, the ability of these organisms to
compete in situ needs to be established on a case-by-case
basis. The addition of microbes and nutrients can be
severely  limited by  low soil permeabilities. Even in
relatively  permeable  soils, ion exchange and filtration
mechanisms can limit the effectiveness of microbial and
nutrient amendments.

The biodegradability of soil contaminants is affected by
the solubility, volatility, and partition coefficients of the
pure compounds. Interactions with the soil and other
contaminants may affect these chemical characteristics.
Aging of  soil contaminants can  lead to binding in soil
pores, which can limit the availability, even of soluble
compounds.  Variable  waste  composition  and
concentration will affect  the  efficiency  of aerobic
biodegradation,  especially in situ.  The  presence of
elevated levels  of heavy  metals, pesticides,  highly
chlorinated organics, and some inorganic salts can inhibit
microbial activity.

The importance of these factors in deciding whether to
initiate or  continue treatability studies can be illustrated
by the following example.
                                                        Example 2.

                    A  remedy screening  test  shows that a contaminant  is aerobically biodegradable.
                    However, soil sampling indicates the contaminant is located more than 25 feet deep in
                    a soil of very low permeability. In situ biodegradation is probably not feasible due to the
                    thickness of the low permeability soil  layer and the depth of the  contaminant. In this
                    case, it may not be worth spending the funds to perform remedy  selection treatability
                    studies for in situ biological treatment  processes.
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                                               SECTION 3
                       THE  USE OF  TREATABILITY STUDIES
                                  IN  REMEDY EVALUATION
        This  section presents an overview of the use of
        treatability tests in confirming the selection of aerobic
        biodegradation as the technology remedy under CERCLA.
        It also provides a decision tree (Figure 3-1) that defines
        the tiered approach to the overall treatability  study
        program with examples of the application of treatability
        studies  to the RI/FS and remedy  evaluation process.
        Subsection 3.1 presents an  overview of the general
        process of conducting treatability tests. Subsection 3.2
        defines  the tiered approach to conducting treatability
        studies and the applicability of each tier of testing, based
        on the information obtained,  to assess,  evaluate, and
        confirm aerobic  biodegradation technology  as  the
        selected remedy.


        Treatability studies should be performed in a systematic
        fashion to ensure that the data  generated can support the
        remedy  evaluation process.  This  section describes  a
        general approach  that should be followed by RPMs,
        PRPs, and contractors  for all  three tiers  of treatability
        studies. This approach includes:

             •    Establishing data quality objectives

             •    Selecting a contracting mechanism

             •    Issuing a work assignment

             •    Preparing the work plan

             •    Preparing the Sampling  and Analysis Plan

             •    Preparing the Health and Safety Plan

             •    Conducting  community  relations

             •    Complying with regulatory requirements
      •    Executing the study

      •    Analyzing and interpreting the data

      •    Reporting the results.

These elements are described in detail in the generic
guide.1-18-1 The generic guide presents general information
applicable to all treatability studies first, followed by
information specific to each of the levels of treatability

Treatability studies for a particular site will often entail
multiple tiers of testing. Duplication of effort  can be
avoided by recognition of this possibility in the early
planning phases of the project. The work assignment,
work plan,  and other  supporting  documents  should
include all anticipated activities to ensure continuity in
the project as it moves from one tier to another.

There are three levels  or tiers of treatability  studies:
remedy screening, remedy selection, and remedy design.
Some or all of the levels may be needed on a case-by-case
basis. The need for and the level of treatability testing
required are management decisions in which the time and
cost necessary to perform the testing are balanced against
the risks inherent in the decision (e.g., selection of an
inappropriate treatment alternative). These decisions are
based on the quantity and quality of data available and on
other decision  factors (e.g., State  and  community
acceptance of  the remedy,  new site  data).  The flow
diagram in Figure 3-1  shows the decision points and
factors to be considered in following the tiered approach
to treatability studies.

Technologies generally  are evaluated first at the remedy
screening level and  progress  through the remedy
selection to the remedy  design level. A technology may
enter, however, at whatever level is appropriate based on
available data on the technology and site-specific factors.
For  example,  a technology  that has  been  studied
extensively  may not warrant remedy screening to
determine whether it
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                               Remedial Investigation/
                               Feasibility Study (RI/FS)
                                              of Alternatives
                                              Record of
                                Remedial Design/
                                Remedial Action -
              -  the -
             Study Scoping
   and Technology
    to Determine
Technology Feasibility
of Alternatives
                                                   REMEDY SELECTION
                                                    to Develop Performance
                                                        and Cost Data
  of Remedy
                                                                                      REMEDY DESIGN
                                                                                    to Develop Scale-Up, Design,
                                                                                      and Detailed Cost Data
                     Figure 3-2. The role of treatability studies in the RI/FS and RD/RA process.
        has the potential to work. Rather, it may go directly to
        remedy selection to verify that performance standards can
        be met. Figure 3-2 shows the relationship of three levels
        of treatability study to  each  other  and to the RI/FS


        Before conducting treatability  studies, the objectives of
        each  tier of testing must be established.   Aerobic
        biodegradation  treatability  study  objectives must  be
        based upon the specific  needs of the RI/FS. There are
        nine  evaluation criteria  specified  in the EPA's RI/FS
        IntenmFmal Guidance Document (OSWER-9335:3-01); the
        treatability studies can provide data upon which up to
        seven of these criteria can be evaluated. These seven
        criteria are:

              •    Overall  protection of human  health  and

                   Compliance with applicable or relevant and
                   appropriate requirements (ARARs)
                                           Reduction of toxicity, mobility, or volume
                                           through treatment

                                      •    Short-term effectiveness

                                      •    Implementability

                                      •    Long-term effectiveness and permanence


                                The first four of these evaluation criteria deal directly or
                                indirectly with the degree of  contaminant reduction
                                achievable by the aerobic biodegradation process. How
                                "clean"  will the treated  soil  be?  Will the  residual
                                contaminant levels be sufficiently low to meet the risk-
                                based contaminant levels established to ensure that the
                                treatment technology achieves and maintains protection
                                of human health and the  environment? What are  the
                                contaminant concentrations and physical and chemical
                                differences between the untreated and the treated soil
                                (e.g., has contaminant toxicity, mobility, and volume been
                                reduced through treatment?)? The  fourth criterion,
                                short-term effectiveness, addresses the effects of  the
                                treatment technology  during  the  construction  and
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        tation of a remedy until the response objectives have
        been met.

        The implementability assessment evaluates the technical
        and administrative feasibility of alternatives and  the
        availability of required goods and services. The key to
        assessing aerobic biodegradation under these criteria is
        whether the  contaminant  is  biodegradable  under
        site-specific conditions.  Additionally, the assessment
        evaluates whether vendors and process equipment  are
        available to perform the remediation,  if adequate space
        exists to perform treatment operations, and what materials
        handling problems  might be encountered if soil must be

        Long-term effectiveness assesses how effective treatment
        technologies are  in maintaining protection  of human
        health  and the environment after response objectives
        have been met. Basically, the magnitude of any residual
        risk and the adequacy and reliability of controls must be
        evaluated. The residual risk factor, as applied to aerobic
        biodegradation, assesses the risks remaining from residual
        contaminant concentrations at the conclusion of remedial

        The final EPA evaluation criterion that can specifically be
        addressed  during a treatability study is cost. Aerobic
        biodegradation is basically  a process that biologically
        degrades organic compounds to carbon dioxide and water
        or to some  intermediate  degradation  product. Remedy
        design treatability studies provide data to estimate  the
        following important cost factors:

                    The initial design of the full-scale unit

              •     The estimated   capital   and operating   and
                    maintenance costs

                    Initial estimate of the  time required to achieve
                    target concentrations.

        hi some cases, remedy selection  treatability studies can
        provide preliminary estimates of the same cost factors.
        3.2.1    Remedy Screening

        Remedy screening is the first level of testing. It is used to
        establish the validity of a technology to treat a waste.
        These  studies  are  generally  low  cost  (e.g.,
        $10,000-$50,000) and usually require 1  week to several
        months to complete. They yield data that can be used as
        a preliminary indication  of a technology's potential to
        meet  performance  goals  and  can identify  operating
        standards  for  investigation  during remedy selection
        testing. They generate little, if any, design or cost data
        and should not be used as the sole basis for selection of
        a remedy.
Typically, aerobic biological remedy screening studies are
performed  in  test reactors provided  with sufficient
nutrients and oxygen. Generally, these studies are batch
processes. These reactors may be small sacrificial batch
reactors (approximately 40 ml to 1 liter in size) or larger
ecosystems (1 to 10 liters) that are subsampled to monitor
the progress of biodegradation. The reactors may contain
saturated or unsaturated soil or slurries  in water. Slurry -
phase  treatability tests  optimize the  availability of
nutrients  and oxygen and offer  the  best  chance of
success for remedy screening studies. Normally, pH and
contaminant loading rates are adjusted to increase the
chances  of success.  The microbial population can be
indigenous to  the site, from another acclimated source
(i.e., wastewater treatment sludge or another area on site),
selectively cultured, a proprietary mixture provided by a
vendor, or any combination of the above. The bioreactors
are set up for replicate sampling at several time points.
The test reactors are compared to inhibited controls at
each  time point to  determine if aerobic biological
degradation occurred. The inhibited reactors are treated
with sterilization agents in an effort to reduce or eliminate
the biological  activity in the control reactors. The mean
contaminant  concentration in  the  inhibited control
replicates  is  compared to the  mean  contaminant
concentration in the  test  reactors. The  goal  for a
successful treatability test is a removal rate, due to
biological processes, that is greater than the analytical
error inherent in the test design.  A reduction of the
contaminant concentration over  a 3- to 6-week period of
20 percent (minimum) to 50 or 60 percent (corrected for
non-biological losses) would be typical of a successful
treatability study.  However, for some  contaminants,
slower degradation rates may  still indicate favorable
results. More information  on experimental design is
provided in Subsection 4.2.

Example 3 illustrates the type of information that might
result from a remedy screening study and the conclusions
that might be drawn from that information.

However, even if the remedy screening tests do not meet
the established goals, the test results should be examined
forthe potential cause(s) of failure. If such parameters can
be adjusted or  corrected to improve the chances of
success of the remedy screening studies, the  RPM or
contractor should consider running additional remedy
screening tests.

3.2.2  Remedy Selection

Remedy selection testing is the second level of testing. It
is  used to  identify the technology's performance on a
waste-specific basis for an operable unit. These studies
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                                                       Example 3.

                    A site contains 27,000 cubic yards of soil contaminated with chlorinated hydrocarbons.
                    A remedy screening study is being performed to determine if bioremediation is a viable
                    cleanup method for the soil.  The objectives of the study in this case would  be to
                    determine if biological processes could  reduce the average chlorinated hydrocarbon
                    concentration by greater than 20 percent, as compared to a chemically inhibited
                    control, in a  6-week study. The mean contaminant concentration, corrected for the
                    abiotic control, shows a 38 percent reduction after two months. The RPM decides that
                    aerobic biodegradation is a potentially viable technology and that remedy selection
                    studies are warranted.
        generally are of moderate cost (e.g., $50,000-$250,000) and
        may require several weeks to months to complete. They
        yield data that verify that the technology is likely to meet
        expected cleanup goals and can provide information in
        support of the detailed analysis of the alternative (i.e.,
        seven of the nine evaluation criteria).

        The remedy  selection tier of  testing for  aerobic
        biodegradation normally consists of bench-scale tests
        which provide sufficient experimental controls such that
        a  quantitative  mass-balance can be achieved.  Such
        studies often incorporate volatile traps. Toxicity testing of
        residual  contaminants and intermediate  degradation
        products is usually required. At the remedy  selection
        level, reduction of organic contaminants to the cleanup
        goals, over a 1- to 3-month period, would  signify  the
        treatability  test  was  a success.  The exact removal
        efficiency specified as the goal for the remedy, selection
        test is site specific.

        Pilot-scale testing may be needed for remedy selection,
        especially for complex sites where in situ biodegradation
        is  being considered.  RREL is planning to develop
        additional  guidance  on remedy  selection  treatability
        studies for aerobic biodegradation.

        3.2.3  Remedy Design

        Remedy design testing is the third level of testing. It is
        used  to  provide quantitative performance, cost,  and
        design information for remediating a site. This level of
        testing  also  can produce  data required to  optimize
        performance. These studies are of moderate to high cost
        (e.g., $ 100,000-$500,000) and may require several months
        or more to  complete. Remedy design studies yield data
        that verify performance to a higher degree  than  the
        remedy  selection studies and provide detailed design
        information. They  are performed during the remedy
implementation phase of a site cleanup.

Remedy design tests usually consist of bringing a mobile
treatment unit onto the site or constructing a small-scale
unit for non-mobile technologies. In some cases, remedy
design tests may be a continuation of remedy selection
tests using the same apparatus. A complete mass balance,
including all  non-biological  pathways,   should  be
performed at this level of testing. Typical testing periods
are from 2 to 6 months. For more complex sites (e.g., sites
with different types of contaminants in different areas or
with different geological structures in different areas),
longer testing periods may be required.

The goal of this tier of testing is to confirm the cleanup
levels and treatment times specified in Subsection 4.1.1.
This  is  achieved by  operating  a  field  unit  under
conditions  similar to those  expected in the full-scale
remediation project.

Data obtained from the pilot-scale tests should be used as

      •    Design full-scale unit

      •    Determine   feasibility   of  aerobic
           biodegradation based on target  cleanup

      •    Refine cleanup time estimates

      •    Refine cost predictions.

Given the lack of full-scale experience with innovative
technologies, remedy design testing will generally be
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                                             SECTION  4
                                            WORK  PLAN
       Section 4 of this document is written assuming that a
       Remedial Project  Manager is requesting treatability
       studies through a work assignment/work plan mechanism.
       Although the discussion focuses on this mechanism, it
       would also apply to situations where other contracting
       mechanisms are used.

       This section focuses on specific elements of the Work
       Plan that require detailed discussion because they relate
       to the remedy screening level of aerobic biodegradation
       treatability studies but are not presented in other sections
       of the document. These elements  include  test  goals,
       experimental design  and  procedures,  equipment and
       materials, reports, schedule, management and staffing,
       and budget. These elements are described in Subsections
       4.1 through 4.9. Complementing these subsections are
       Section 5, Sampling and Analysis Plan, which includes the
       Quality  Assurance Project  Plan,  and  Section   6,
       Treatability Data Interpretation, that address the sampling
       and analysis and data analysis and interpretation ele-
ments of the Work Plan. The Work Plan elements are
listed in Table 4-1.

Carefully planned treatability studies are necessary to
ensure that the data generated are useful for evaluating
the validity or performance of a technology. The Work
Plan, which is prepared by the contractor when the Work
Assignment is  in  place,  sets  forth the contractor's
proposed technical approach for completing the tasks
outlined in the Work  Assignment.  It also  assigns
responsibilities and establishes the project schedule and
costs. The  Work Plan must be approved by the RPM
before initiating subsequent tasks. For more information
on each of these sections, refer to the generic guide/18'


Setting goals for the treatability study is critical to the
ultimate usefulness of the data generated. Goals must be
defined before
                    Table 4-1.       Suggested Organization of Aerobic Biodegradation
                                      Remedy Screening Treatability Study Work Plan

                           1.    Project Description
                           2.    Remedial Technology Description
                           3.    Test Goals (see Subsection 4.1)
                           4.    Experimental Design and Procedures (see Subsection 4.2)
                           5.    Equipment and Materials (see Subsection 4.3)
                           6.    Sampling and Analysis (see Subsection 4.4)
                           7.    Data Management
                           8.    Data Analysis and Interpretation (see Subsection 4.5)
                           9.    Health and Safety
                           10.  Residuals Management
                           11.  Community Relations
                           12.  Reports (see Subsection 4.6)
                           13.  Schedule (see Subsection 4.7)
                           14.  Management and Staffing (see Subsection 4.8)
                           15.  Budget (see Subsection 4.9)
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        the treatability  study  is performed. Each tier of the
        treatability study needs performance goals appropriate to
        that tier. For example, to use remedy screening tests to
        answer the question, "Does aerobic biodegradation work
        on this contaminant?," it is necessary to define "work"
        (i.e., set the goal ofthe study). A pollutant reduction of at
        least 20 percent during the remedy screening tests may
        satisfy the test for validity of the process and indicate
        that further testing at the remedy selection  level is
        appropriate to determine if the technology  can meet the
        anticipated performance criteria ofthe ROD.

        4.1.1    Remedy Screening Goals

        The main goals ofthe remedy screening evaluation are to:

             •   Provide an indication that reductions in
                 contaminant concentrations are due to
                 biodegradation and not abiotic processes
                 such as photodecomposition, volatilization,
                 and adsorption

             •   Produce the design information required for
                 the next level of testing, should the screening
                 evaluation be successful.

        Normally, the average contaminant concentration should
        be reduced by at least  20 percent during a 6- to 8-week
        study, as compared to  an inhibited control, to conclude
        aerobic  biodegradation  is   a   potential  treatment
        technology  for the  site under  investigation.  The
        20-percent  contaminant reduction is  arbitrary, but is
        designed to maximize the chances of success  at the
        remedy screening tier. The choice of a 6- to 8-week study
        is to provide a consistent endpoint for remedy screening
        studies. The choice of the remedy screening treatability
        study  goals (time and contaminant reduction) will be
        site-specific decisions.
Example 4 is provided to demonstrate typical goals of a
remedy screening study and what decision can be made
when these goals are achieved.


A number of different approaches can be used to conduct
the remedy screening test. These range from simple shake
flask evaluations to soil pans or soil slurry reactors. The
soil may be either saturated orunsaturated, depending on
the goals ofthe study.  Soil slurries will optimize mixing
and will tend to maximize biological degradation.  Such
studies  will maximize the chances, of success at the
remedy screening level. Unsaturated soils will often limit
mixing and result in slower degradation rates. However,
such systems will correlate better with field conditions in
many cases and result  in better extrapolation to remedy
selection test  systems.  The  object of this  guidance
document is not to specify a particular remedy screening
method but rather to highlight those  critical parameters
that should be evaluated during the laboratory test.

The test should include controls to measure the impact of
non-biological processes such as volatilization, sorption,
and  photodecomposition on  the  concentrations of
contaminants. Inhibited controls can be established by
using formaldehyde, mercuric chloride, or sodium azide to
inhibit microbiological activity. However, care should be
exercised when selecting a sterilizing agent. For example,
sodium azide can, under certain circumstances, promote
spontaneous explosive  reactions.  Mercuric  chloride
complexes certain petroleum hydrocarbons and results in
artificially low hydrocarbon concentrations. Soil structure
also  can be modified by sterilization agents.  Complete
sterilization of soils can be difficult to accomplish. Incom-
                                                       Example 4

                      The soil of a former wood-preserving site is contaminated with pentachlorophenol
                      (PCP) waste.  The  literature  search indicated that PCP has been successfully
                      biodegraded atothersites. The RPM decided a remedy screening study was needed
                      to measure the potential for successful biodegradation at this site. A goal of 25
                      percent reduction ofthe PCP concentrations was set. The study period was set at 6
                      to 8 weeks. These study goals were established to maximize the chances of success
                      for biodegradation.

                      A remedy screening study was performed to determine if bioremediation is a viable
                      cleanup method for the soil. The average  PCP concentration was reduced  by 37
                      percent, over a 6-week period, after correction for the inhibited control. The RPM
                      decided that further treatability studies were warranted and elected to have  a remedy
                      selection treatability study performed to attempt to optimize degradation.
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        plete mixing of sterilization agents with soils can result in
        pockets of surviving microbes in soil pores. In some
        cases, microbial populations can transform and detoxify
        sterilizing agents. Complete sterilization of the control is
        not necessary provided that biological activity is inhibited
        sufficiently so that a  statistically significant difference
        between the test and control means can be determined.
        However,  care  should be taken in interpreting remedy
        screening study results. Substantial degradation in the
        control (e.g., 20-50 percent contaminant reduction, or
        more) can mask the occurrence of biodegradation in the
        test reactor. If the control reactor has the same or greater
        percent degradation as the test reactor, a false negative
        conclusion can result. Concluding that no biodegradation
        occurred, when in fact there was some biodegradation,
        can lead to elimination of this technology unnecessarily.
        Alternatively, closed test systems with volatile traps can
        be used to monitor  the volatilization  of compounds
        instead of using inhibited controls to estimate abiotic

        A statistical experimental design should  be used to
        conduct the treatability  study in order  to  support
        decisions  made from the treatability data. The various
        parameters of interest are included as factors in  the
        experimental design. The treatability experiment should
        include monitoring the concentration of chemicals of
        interest over time.  In general, at least three to four time
        periods should be  studied, including the time-zero (T0)
        analysis. However, if the study goals are met after  a
        sampling  period, then it is not  necessary to continue
        sampling  at additional time periods.  (For  example, if
        70-percent reduction was achieved after 1 week, it would
        not be necessary to continue testing if the goal was to
        achieve only a 20-percent reduction.)

        The test system can consist of a single large reactor or
        multiple small reactors. In the case of the single reactor,
        small subsamples  are removed  at  various  times   and
        compared to subsamples from a second reactor in which
        biological activity has been inhibited. Normally, triplicate
        subsamples are taken at  each time point.  The mean
        contaminant  concentrations  in  the test and  control
        reactors are compared to see if a statistically significant
        change in  concentration  has  occurred,  The  mean
        contaminant  concentration  in  the  inhibited  control
        subsample can be subtracted  from that in the  test
        subsample to estimate the percentage the contaminant
        has biodegraded at each time  point.  In this type of
        system, heterogeneity within the soil system can lead to
        variability  in  contaminant concentration  among  the
        various subsamples and replicates. However, such system
        variability can be overcome by thorough mixing of the soil
        before it is distributed to the test and control systems.
        Examples of this type of system are large flasks, soil pans,
        and other large soil reactors. Care should be taken so that
        the system size and design do not limit the availability of
oxygen and moisture and cause variability in degradation
rates within the reactor.

Multiple reactors may be set up in place of a large soil
system. Triplicate reactors are established for each test
reactor and control group at each time point. Each reactor
is  filled  with the same amount of soil  and nutrient
additives. In this case, the complete reactor contents are
extracted and analyzed for each of the triplicate test and
control reactors  at each time point. Examples of such
systems are serum bottles, slurry reactors, and aerated
soil reactors. The advantage of this type of experimental
apparatus  is that  the  question  of subsampling
representativeness   is   avoided.  However,   the
representativeness of any one reactor is  questionable in
this design. Thorough mixing of the soil, before it is
distributed among the individual reactors, is important.

Triplicate  samples provide a  measure  of the  overall
precision of the  measurements made. Surrogate spikes
should also be added to the matrix samples to ensure
consistent analytical performance. Matrix spikes should
be added  to a percentage (approximately 10%) of the
samples to determine overall analytical accuracy. Method
blanks should be used to monitor potential contamination
of samples during laboratory handling.

Respirometric  measurements  or  other measures  of
biological activity can be used to predict the best times to
take samples. At the beginning of the experiment, activity
measurements should indicate minimal biological activity.
Continued monitoring  can  reveal either a rapid or
relatively slow onset of  biological activity and indicate
when samples should be taken to monitor contaminant
reductions. However, respirometric measurements can
indicate the loss of oxygen through chemical oxidation in
addition to biodegradation.1-7'1-10'1-27-1

In formulating an experimental design, the total number of
samples taken depends on  the desired difference in
concentrations that the experimenter wishes to detect, the
measurement variability (the analytical coefficient of
variation), and the type I and type II error probabilities.
Each of these factors is discussed below.

The goal of the  remedy screening scale of treatability
testing is  not to  be able to  ascertain whether the
biotreatment process can meet cleanup  goals but rather
whether biodegradation is possible with the site-specific
waste material in  question.  Therefore,  at the remedy
screening scale, it is usually not necessary to establish
complete removal of the contaminant of interest. As  a
guide, the experiment  should be designed so that  a
difference of 20 to 50 percent removal of the contaminant
of interest can be detected between the treatment and the
inhibited control.
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        In general, for sampling and analysis of soils and sludges,
        the analytical variability can be quite high (on the order of
        20 to 50 percent). Therefore,  a  sufficient number of
        samples must be taken for statistically significant effects
        to be observed. Additional information on sample size
        selection is available in many statistical textbooks.(2)(5-"-9)

        The  type  I  error  probability  is the  chance of  the
        experiment  indicating  that  there  is   a  statistically
        significant treatment effect when,  in reality, there is not.
        Conversely, the type II error probability is the chance of
        not detecting a significant treatment effect when, in
        reality, the  treatment  was effective.   Traditionally,
        experimentaldesigns have been constructed so that these
        error probabilities are on the order of 5 percent (i.e., 95
        percent confidence levels). This error probability  is not
        appropriate for the remedy screening scale of treatability
        testing. Error rates on the order of 10 to 20 percent (i.e., 80
        to 90 percent confidence levels) are more consistent with
        the philosophy of remedy screening.

        It is beyond the scope of this document to go into great
        detail on experimental design but many good texts on the
        subject are available.1-2-"-9'
An example of a simple experimental design is included in
Example 5.


The Work Plan should specify the types of equipment
and materials to be used during the treatability test. For
example, the size and type of glassware to be used during
the test should be specified. Standard laboratory methods
normally dictate the types of sampling containers that can
be used with various contaminant groups. The RPM
should consult such references for the appropriate
containers  to be  used for the  treatability studies.1-24-1
Normally, glass reactors with Teflonฎ fittings should be
used.  Stainless  steel also can be  used with most
contaminants. Care should be taken when using various
plastic containers and Tygonฎ tubing. Such materials will
adsorb many contaminants and also can leach plasticizer
chemicals,  such  as  phthalates,  into the  soil  matrix.
Typically,  such  analytical   equipment  as   gas
chromatograph (GC), high-pressure liquid chromatograph
(HPLC), total organic carbon (TOC) analyzers, and pH
meters will be required.
                                          Example 5. Bioremediation Study

                    Twenty-four 20-gram samples of soil containing approximately 100 ppm phenol were
                    added to separate 500 ml flasks along with 80  ml  of water containing phosphate
                    buffer (pH = 7.0), ammonium sulfate, and trace metals. Twelve of the resulting soil
                    slurries were  inoculated with a suspension containing approximately  104 phenol
                    degrading bacteria/ml. The other 12 flasks were inoculated and then "sterilized" with
                    mercuric chloride to form the control group. The test and inhibited control flasks were
                    stoppered and stirred at moderate speed on stirring plates while incubating at 20ฐC.
                    Three test flasks were immediately sacrificed (T0) by adding 100 ml of methanol and
                    shaking vigorously to extract the phenol for analysis. One ml subsamples from each
                    flask  were centrifuged at  high speed in a microcentrifuge to remove soil  particles.
                    Phenol was quantified via  high-pressure liquid  chromatograph.  At each of three
                    subsequent time points (T,, T2,  T3), three additional test flasks were sacrificed and
                    subsampled  as previously  described. Three inhibited  control  flasks  were also
                    sacrificed at each time point. The mean phenol concentration of the three test flasks
                    was compared to the mean phenol concentration of the three control flasks at each
                    time point to see if significant biodegradation was occurring.
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        The Work Plan should describe the sampling procedures
        to be used during field sampling and remedy screening
        treatability studies. Appropriate methods for preserving
        samples and specified holding times for those samples
        should be used. The procedures will be site-specific.
        Standard EPA and American Society for Testing and
        Materials (ASTM) methods are generally recommended;
        however,  the  treatability study vendor may propose
        modified or equivalent methods that are more suited to the
        specific treatment process being studied. The EPA RPM
        must determine  the acceptability  of these  alternative
        methods with respect  to the test  objectives and the
        available method validation information provided by the
        vendor. The Work Plan  also  should note  that the
        Sampling and Analysis Plan (SAP) will be prepared before
        field sampling and treatability testing begins. Section 5
        provides details for the preparation of the SAP including
        the Field Sampling Plan (FSP) and the Quality Assurance
        Project Plan (QAPjP).

        4.4.1  Field Sampling

        A sampling plan should be developed that directs the
        collection of representative samples from the site for the
        treatability test. The sampling plan should be site-specific
        and describe the number, location, and volume of samples
        to be collected. Typically, little information is available at
        this point of the RI; therefore, good engineering judgment
        must be used. An adequate volume of soil sample should
        be collected from each  sampling location to account for
        replicate  treatability   tests  and   analytical  quality
        assurance/ quality control (QA/QC) requirements.

        Depending upon the goals  of the remedy screening
        treatability study, samples representative of conditions
        typical of the entire site or defined areas (i.e., hot spots)
        within the site should be collected. The selection of soil
        sampling locations should be based on knowledge of the
        site.  Information from  previous soil samples, soil gas
        analysis using field instrumentation, and obvious odors
        or residues are examples of information that can be used
        to specify sample locations.

        The  method of sample collection  is site-specific. For
        example, drill rigs or hand augers can be used to collect
        samples, depending  on the depth of the sample required
        and the soil characteristics. If the target contaminants are
        volatile, care should be taken to minimize their loss when
        they are composited. Compositing is usually appropriate
        for soils containing non-volatile constituents; however,
        compositing samples  on  ice is  a good  method  of
        minimizing the loss of volatile compounds.
4.4.2   Sampling During the Remedy
        Screening Treatability Study

During the remedy screening treatability study, the extent
of biodegradation is assessed by removing samples from
a large test reactor, or sacrificing the entire contents of
smaller test systems, at predetermined time intervals. The
concentrations of contaminants, at a minimum, should be
determined at the beginning, at some intermediate time
point, and at the end of the experiment. Therefore,  a
minimum of three sampling points is normally required. A
useful approach is to establish enough test systems so
that the remedy screening study can be extended or
additional samples can  be  removed and archived for
analysis, if required,  The length  of the study will be
determined by the biodegradability of the contaminants.
For example, treatability tests for BTEX wastes may be
conducted within 3  to 4 weeks. Tests involving PAHs
may take several months because microorganisms will
likely attack the structurally less complicated molecules
before more complex molecules.  As discussed earlier,
measures of microbial activity may be useful in identifying
appropriate sampling times.

4.4.3  Analysis

The concentrations of some important matrix parameters
are determined  by using standard analytical chemistry
methods (Table 4-2).  These parameters should be
determined before the treatability study  begins. These
parameters  are   important for the design of remedy
selection and remedy design studies; they should not be
used as an indication of the inappropriateness of the

Table 4-2. Commonly Used Analytical Chemistry
           Methods for Soil Parameters
                    Liquid/Sludge          Soil
Moisture               160.3(19)       ASTM2216(1)
Nitrate              9200<24>/300.0<25>         —
Total Organic Carbon  9060<24>/415.1<19>      9060<24>
Total Kjeldahl Nitrogen    351.2(19)       ASTM E 778(1)
Soluble Orthophosphate   365.1(19)            —
Soluble Ammonia        350.1<19>            —
pH                 9040<24>/150.1<19>      9045(24)
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        Contaminant concentrations should be determined at the
        beginning of the study and at the sample times chosen in
        the experimental design. Consult U.S. EPA SW-846(24) for
        the appropriate methods. When determining volatile and
        semi-volatile organics, GC or other appropriate methods
        (e.g., HPLC) should be used whenever possible, rather
        than gas chromatography/mass spectrometry (GC/MS)
        methods, to minimize costs. All sampling and analysis
        should be performed in accordance with the SAP (Section

        4.5   DATA ANALYSIS AND

        The Work Plan should discuss the techniques to be used
        in analyzing and interpreting the data. The following data
        should be reported for each treatability test:

           •     Concentration of chemicals in samples at the
                time of sampling (field concentration) and
                before  the samples are added to the reactors
                (T0 reactor concentration)

           •     Amount of soil used in the reactors and a
                description of all modifications to the reactors

           •     Quantity of residual chemical(s) in each of the
                reactors at each sampling time

           •     Quantity of chemical(s) lost due to abiotic

           •     Temperature profile over the entire experiment
                recorded in a written log indicating type,
                extent, and time of any action

           •     Any other additions, removals, changes,
                manipulations, or mishaps that occur during
                the course of the experiment should be
                recorded in a written log indicating type,
                extent, and time of any action

           •     All cited analytical and microbiological
                procedures (recorded in a written log)

           •     All quality control data (e.g., recovery
                percentage of spikes; contaminant
                concentrations, if any, in experimental  and
                analytical blanks).

        Additional information on the interpretation of treatability
        study data is presented in Section 6 of this document.

        4.6     REPORTS
The  Work Plan should discuss the  organization and
content of interim and final reports. Once the data have
been gathered, analyzed, and interpreted, they must be
incorporated into a report. A suggested organization for
the treatability study report is provided in Subsection 4.12
of the generic guide/18'

If the report indicates  aerobic biodegradation  has
potential (see Section 6 for guidance on interpretation of
treatability data), the project can progress to the next
level. In general, if the average reduction in contaminant
concentration attributable to biodegradation exceeds 20
percent during a 6- to 8-week test period, the  remedy
screening  is considered positive. Additional studies will
be required before selecting a remedy in the ROD.

4.7     SCHEDULE

The  Work  Plan  should  discuss  the  schedule  for
completing the remedy screening treatability study. When
preparing  a schedule for conducting treatability  studies,
it is advantageous to break down the entire process into
distinct tasks that are common to most studies.

Listed below are specific tasks that  should always be
considered when scheduling:

   •     Work Plan preparation

   •     SAP preparation

   •     Sample collection and disposal

   •     Field sample analysis

   •     Treatability test (including analyses)

   •     Data validation

   •     Report preparation.

The  tasks that have the greatest potential for time
variance are usually the Work Plan preparation and the
treatability tests.   The treatability  test  schedule  is
unpredictable  without  a  firm  understanding  of the
contaminant types and  concentrations  involved. For
example, remedy screening treatability tests for BTEX
wastes may be conducted within a couple of weeks; tests
involving PAHs may take several months for the reasons
discussed  in Subsection 4.4.2.

The schedule itself is usually most helpful if displayed in
the form of a bar chart, such as the one shown in Figure
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Task 2
RAP HQP A PPP Prana ration
Treatability Study Execution
Task 4
Data Analysis & Interpretation

Residuals Management


Weeks from Project Start

9 10 !l|l2

-3 M-4

( M

I3J14 is] is

-5 N
r ^


•6 M-7
VJl^ -



2SJ2SJ27 28

M-12 M
-- ^ ^

13 M
r j

i 1
M-10 M-ll M-14 M-16


           ••ซ• n Administrative approval, document review, or sample turnaround

           M-l  Submit Work Plan                    Wk2
           M-2  Receive Work Plan Approval            Wk4
           M-3  Submit SAP, HSP.CRP               Wk8
           M-4  Receive SAP, HSP Approvals           Wk10
           M-S  Collect Sample                      Wk12
           M-6  Receive Sample Characterization Results  Wk16
           M-7  Collect Treatability Study Samples        Wk18
           M-8  Collect Project Residual Samples        Wk18
 M-9  Receive Treatability Study Analytical Results  Wk 22
 M-10 Receive Project Residual Analytical Results  Wk 22
 M-ll Submit Waste Disposal Approval Form      Wk24
 M-12 Submit Draft Report                    Wk26
 M-13 Receive Review Comments              Wk 28
 M-14 Receive Waste Disposal Approval          Wk28
 M-15 Submit Final Report; Conduct Briefing       Wk 30
 M-16 Ship Wastes to TSDF                   Wk30

        The  Work Plan should discuss the management and
        staffing of the remedy screening treatability study and
        identify the  personnel who will be  responsible  for
        executing the treatability study at this level. Generally, the
        following  expertise  is  needed   for  the  successful
        completion of the remedy screening treatability study:

           •     Project manager (work assignment manager)

           •     Chemist

           •     Microbiologist   ,environmental   scientist/
                 engineer, or bioengineer

           •     Lab technician

           •     Quality assurance manager.

        Responsibility  for  various  aspects of the project is
        typically shown in an organizational chart such as the one
        in Figure 4-2.
4.9     BUDGET

The Work Plan should discuss the budget for completion
of the remedy screening treatability study. The cost of
biotreatability  evaluations   varies   tremendously.
Historically, the  cause of this  wide variation has been
significant differences in the scope of work associated
with specific site characteristics. The lack of established
standard  procedures,  to   date,  for   performing
biotreatability evaluations has  led remediation firms to
develop their own "standard procedures." This guide will
serve as an important aid in accurately defining data that
should  be  produced  from a biotreatability remedy
screening evaluation and ensuring that the data will be
sufficient  for deciding whether to proceed to  the next
phase of development of the bioremediation process.

The cost of the remedy screening phase is directly related
to the method of sample collection, the number of samples
collected, the type and number of chemical  analyses
performed on samples, and the number of replicate remedy
screening tests performed. The factor which is most likely
to influence the cost of the remedy screening is the ana-
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                      CONTRACTOR or WORK
                      ASSIGNMENT MANAGER
                       • Report to EPA Remedial
                        Project Manager
                       • Supervise overall project
                     SCIENTIST/ENGINEER or
                     • Oversee Treatability
                      Study execution
                     • Prepare applicable sections
                      of Report and Work Plan
         • Oversee Quality Assurance
         • Prepare applicable sections
          of Report and Work Plan
         • Oversee sample collection
          and analysis
         • Prepare applicable sections
          of Report and Work Plan
                                            LAB TECHNICIAN
                                            • Perform Treatability Study
                                            • Sample collection and analysis
                                          Figure 4-2.  Organization chart.
        lytical costs which are directly tied in with the number of   rather than GC/MS methods also should help to minimize
        replicates. One method to minimize costs is to use an
        inexpensive  analysis of an indicator parameter and to
        perform a limited  number of analyses for the more
        expensive volatile and semi-volatile priority pollutants.
costs. Table 4-3  summarizes the major cost elements
associated with remedy screening treatability tests for
biodegradation of a contaminated site.
                         Table 4-3.        Major Cost Elements Associated with Aerobic
                                            Biological Remedy Screening Treatability
                         Cost Element
                         Work Plan Preparation
                         SAP Preparation
                         Field Sample Collection
                         Field Sample Chemical Analysis
                         Laboratory Setup/Materials
                         Treatability Test Chemical Analysis
                         Data Presentation/Report
                              TOTAL COST RANGE
            Cost Range
       (thousands of dollars)
               1 -5
               1 -5
               1 -5
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                                                 SECTION 5
                            SAMPLING AND ANALYSIS  PLAN
        The SAP consists of two parts - the Field Sampling Plan
        (FSP) and the QAPjP. This section identifies the contents
        of and aids in the preparation of these plans. A SAP is
        required for all field activities conducted during the RI/FS.
        The  purpose  of the  SAP  is  to ensure that  samples
        obtained  for  characterization  and  testing  are
        representative and that the quality of the analytical data
        generated is known. The SAP addresses field sampling,
        waste characterization, and sampling and analysis of the
        treated wastes and residuals from the testing apparatus or
        treatment unit. The SAP is usually prepared after the
        Work Plan is approved.


        The FSP component of the SAP describes the sampling
        objectives; the type, location, and number of samples to
        be collected; the sample numbering system; the necessary
        equipment and procedures for collecting the samples; the
        sample chain-of-custody procedures; and the required
        packaging, labeling, and shipping procedures.

        Field samples are taken to provide baseline contaminant
        concentrations and material for the treatability  studies.
        The  sampling objectives must be consistent with the
        treatability test objectives. Because the primary objective
        of remedy  screening studies is to provide a first-cut
        evaluation of the extent to which specific chemicals are
        removed from the soil by biological process, the primary
        sampling objectives should include, in general:

            •   Acquisition of samples representative of
                conditions typical of the entire site or defined
                areas within the site. Because this is a fast-cut
                evaluation, elaborate, statistically designed
                field sampling plans may not be required.
                Professional judgment regarding the sampling
                locations should be exercised to select
                sampling sites that are typical of the area (pit,
                lagoon, etc.) or appear above the average
                concentration of contaminants in the area
                being considered for the treatability test. This
                may be difficult because reliable site
        characterization data may not be available early
        in the remedial investigation.

    •   Acquisition of sufficient sample volumes
        necessary for testing, analysis, and quality
        assurance and quality control.

From these  two  primary  objectives, more  specific
objectives should be developed. When developing the
more detailed objectives, the following types of questions
should be considered.

    •   Will samples be composited to provide more
        representative samples for the treatability test,
        or will the potential loss of target VOCs
        prohibit this sample collection technique?

    •   Are there adequate data to determine sampling
        locations indicative of the more contaminated
        areas of the site?

    •   Is sampling of a worst-case scenario warranted
        to determine if either indigenous or inoculated
        microorganisms are able to break down
        contaminants at their highest known
        concentrations in the field.

After the sampling objectives are clearly identified, an
appropriate  sampling strategy   should be  described.
Specific items that should be briefly discussed are:

    •   Sampling objectives

    •   Calibration procedures

    •   Sample location selection

    •   Sample collection

    •   Sampling procedures

    •   Sample transportation

    •   Sampling equipment

    •   Responsible persons

    •   Sample media type

    •   Sampling strategy
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            •    Sample location map

            •   Sample history recording procedures

            •   Sample preservation methods/holding times

            •   Sample custody  and chain-of-custody

        Table 5-1 presents the suggested organization of the
         TABLE 5-1. Suggested Organization of the Sampling
                        and Analysis Plan

          Field Sampling Plan

          1.   Site Background
          2.   Sampling Objectives
          3.   Sample Location and Sampling Frequency
          4.   Sample Designation
          5.   Sampling Equipment and Procedures
          6.   Sample Handling and Analysis

          Quality Assurance Project Plan
          1.   Experimental Design
          2.   Quality Assurance Objectives
          3.   Sampling and Analytical Procedures
          4.   Approach to QA/QC
        The QAPjP should be consistent with the overall
        objectives of the treatability study. At the remedy
        screening level, the QAPjP should not be overly

        5.2.1   Experimental Design

        Section 1 of the QAPjP must include an experimental
        project description that clearly defines the experimental
        design, the experimental sequence of events, each type
        of critical measurement to be made, each type of matrix
        (experimental setup) to be sampled, and each type of
        system to be monitored. This section may reference
        Section 4 of the Work Plan; however, all details of the
        experimental design not finalized in the Work Plan
should be defined in this section.

The following items should be included:

    •   Number of samples (area) to be studied

    •   Identification of treatment conditions
        (variables) to be studied for each sample

    •   Type of reactors to be used for each sample

    •   Target compounds for each sample

    •   Number of replicates per condition per
        sampling event

    •   Number and time  of each sampling event.

The  project description  should clearly  define  and
distinguish the  types  of  critical  measurements or
observations that will be  made, as well as any system
conditions  (e.g.,  process  controls  or  operating
parameters) that will need to be monitored routinely.
Critical  measurements  are  those measurement,
data-gathering, or data-generating activities that directly
affect the technical objectives of aproject. At aminimum,
the determination of the  target compound (identified
above) in the initial soil and treated soil samples will be
critical measurements.

The purpose of the remedy screening treatability study is
to determine whether biological treatment is potentially
applicable to the site under consideration. An example of
a criterion for this determination is a 20 percent reduction
in concentration of the select target compounds at the 80
percent  confidence level.  If a 20 percent reduction is
obtained, then additional remedy selection studies would
be indicated to optimize the treatment and determine the
cost-effectiveness in comparison to other technologies.

5.2.2   Quality Assurance Objectives

Section 2 should list the QA objectives for each type of
critical measurement and for each type  of sample matrix
defined in Section  1, for  each  of the six data quality
indicators:  precision,   accuracy,  completeness,
representativeness, comparability, and, where applicable,
method  detection limit.  See reference  21 for additional
information on the preparation of a QAPjP.

5.2.3   Sampling and Analytical Procedures

The procedures used to obtain the field samples for the
remedy screening treatability study are described in the
FSP and need not be repeated in this section, but should
be incorporated by reference.
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        Section 3 of the QAPjP, therefore, should contain a
        credible plan for subsampling the material for the remedy
        screening treatability study. Also, if the reactor contents
        are sacrificed for analysis, the methods for aliquoting the
        residual material in each reactor for different analytical
        methods must be described.

        This  section should also describe or reference  an
        appropriate analytical method and a standard operating
        procedure for implementing the analytical method for each
        type of critical measurement to be made. In addition, the
        calibration  procedures and  frequency of  calibration
        should be discussed or referenced for each analytical
        system, instrument, device, or technique used to obtain
        critical measurement data.

        The methods used for analyzing the treatability study
        samples should be the same as those used for chemical
        characterization of field samples. Preference should be
        given to methods in "Test Methods for Evaluating Solid
        Waste." (24)  If applicable,  methods other than GC/MS
        methods are recommended to conserve costs.

        5.2.4  Approach to QA/QC

        The treatability study is designed to compare the results
        of a biological reactor to an inhibited control reactor over
        a period of time. Replicate samples (three) are  taken of
        both experimental setups at T0, Tb and at least a T2. The
        inhibited control is run and analyzed to account for losses
        of the target compounds due to any cause other than
        biodegradation (e.g., volatilization, adsorption).

        The intended purpose of this  study is to determine if the
        concentration of the target  compounds decreases at least
        20 percent in the biological reactor compared to
the inhibited control at an 80 percent confidence level.
Only the relative accuracy of the analytical measurements
and the overall precision of the experiments are important.

The suggested QC approach will consist of:

    •   Triplicate samples of both reactor and
        inhibited control at each sampling time

    •   The analysis of surrogate spike compounds in
        each sample

    •   The extraction and analysis of a method blank
        with each set of samples

    •   The analysis of a matrix spike in approximately
        10 percent of the samples.

The analysis of triplicate samples provides for the overall
precision measurements that are necessary to determine
whether the difference is significant at the 80 percent
confidence level. The analysis of the surrogate spike will
determine if the analytical  method  performance  is
consistent (relatively accurate). The matrix spike will be
used to measure overall analytical accuracy. The method
blank will show if laboratory contamination has had an
effect on the analytical results.

Selection  of appropriate  surrogate  compounds will
depend on the target compounds identified in the soil and
the analytical methods selected for the analysis.
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                                           SECTION  6
       This section is designed to help the RPM or contractor to
       interpret treatability data in screening and selecting a
       remedy. The information and results gathered from the
       remedy screening are used to determine if bioremediation
       is a viable treatment option and to determine if additional
       remedy selection and remedy design studies are needed
       prior to the implementation of a full-scale bioremediation
       process. A threshold of greater than 20 percent reduction
       in the concentrations of the compounds of concern, com-
pared to the abiotic control, indicates that bioremediation
is potentially a viable cleanup method and further testing
is warranted. For some compounds or sites, a period of
time longer than the typical 6-8 weeks may be indicative
of a successful remedy screening study. An example
method for  interpreting the  results  from  a  remedy
screening treatability study is provided below. Other valid
statistical methods may be used as appropriate.
Example 6.
In a remedy screening treatability study for soil contaminated with a solvent, the average
solvent concentrations in both the inhibited control and in the biologically active system were
1 300 ppm at T0 . The average solvent concentration in the inhibited control was reduced to 550
ppm (T3), a reduction of greater than 57 percent (Table 6-1). The average hydrocarbon
concentration In the biologically active system was reduced to 200 ppm CQ, a reduction of
greater than 84 percent for the same time period.

Table 6-1. Hydrocarbon Concentration (ppm) Versus Time
Inhibited Control (C)
Replicate 1
Replicate 2
Replicate 3
Mean Value
Concentration Change
(Ci0-Ci,) (1 = 0,1,2,3)
Bioreactor (CJ
Replicate 1
Replicate 2
Replicate 3
Mean Value
Concentration Decrease
(Cb0-Cbt) (T = 0,l,2,3)
T0 Tt T2 T3
1220 1090 695 575
1300 854 . 780 580
1380 1056 6Jฃ 495
1300 (Ci0) ioqo (eg 721 (eg 550 (eg
0 -300 -579 -750

1327 982 550 225
1320 865 674 310
1253 703 666 65
1300 (Cb0) 850 (Cb,) 630 (Cb2) 200 (Q>3)
0 -450 -670 -1100

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                   The average contaminant concentration of the bioreactor, at each time point, is corrected
                by the average contaminant concentration of the inhibited control, at the same time point, to
                measure the biodegradation at that time point. The inhibited control accounts for contaminant
                losses  due to  volatilization,  adsorption to soil particles, and chemical reactions. Some
                contaminant loss in the control due to biodegradation may occur since total sterilization is
                difficult to accomplish. However, if a statistically significant difference between the test and
                control means exists, then biodegradation has occurred in the test bioreactor. The difference
                between the two means is tested using Analysis of Variance (ANOVA) methods at the 80
                percent confidence level for each of the test times. If the difference between the two means
                is significant at T,, no further test measurements are required. If the difference between the
                two means is not significant at  T,, then the remedy screening test continues until some T2.
                This process is repeated until a statistically significant difference between the two means is
                found or the treatability study is determined to be unsuccessful and is discontinued. In this
                example, a statistically significant difference between the two means occurs at T3. The data,
                therefore, indicate that bioremediation is a viable treatment option and that further remedy
                selection studies are appropriate. The 80%  confidence interval about each mean is shown in
                Figure 6-1 to graphically describe the variation associated with each mean.
                             •! —








                                                           T1         T2
                                          A inhibited control      • non-inhibited control
                            Table 6-1.  Plot of hydrocarbon concentration versus time.
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        If the remedy screening indicates that bioremediation is a
        potential cleanup option then remedy selection studies
        should be performed. Remedy  selection testing is the
        second  level  of testing.  It  is used to identify  the
        technology performance on a contaminant-specific basis.
        Costs for these studies generally range from $50,000 to
        $250,000. They yield data that verify that the technology
        can  meet expected clean up  goals and can provide
        information in support of the detailed  analysis of the
        alternative (i.e., the nine evaluation criteria).

        During  the remedy  selection studies,  microcosms
        designed   to   simulate   the  proposed  full-scale
        bioremediation  system   are   generally  established.
        Specifically,the goals of the remedy selection microcosms
        are to:

             •   Estimate the rate at which the contaminants
                can be biodegraded
             •   Determine the impact of parameters such as
                nutrient addition, loading  rate, and inoculation
                on the rate of biodegradation

             •   Estimate the cleanup levels achievable
             •   Develop design parameters for the next level of
             •   Develop preliminary cost and time estimates
                for full-scale bioremediation.

        If required, several bioremediation processes can  be
        evaluated simultaneously to determine which process or
        combination of processes is most appropriate for the
        cleanup of a given site.  For example, if the affected
        materials at a site can be effectively remediated with either
        a  solid-phase  or a slurry-phase  biological  treatment
        process, both  of these processes may be  evaluated
        simultaneously.  The  biodegradation  rates  measured
        during the solid-phase and slurry-phase remedy selection
        evaluations can then be used to estimate the treatment
        time, equipment, and land area required by each treatment
        process. This procedure permits determination of which
process or combination of processes can achieve most
cost-effectively, the required cleanup levels in the
required period of time.  If sufficient  design  and cost
information are acquired during the remedy selection tests
to permit full-scale system design, furtherremedy design
testing may be unnecessary.

Remedy design testing is the third level of testing in the
RI/FS process. These  studies  generally  range  from
$100,000 to $500,000. As discussed in the preceding
paragraph, remedy design studies are not always required.
When  remedy  design  tests  are performed, they are
typically  post-ROD. Therefore,  if  a  remedy design
programis conducted, it should produce the data required
forfinal full-scale remedy design and costing. The remedy
design program is usually conducted on-site and should
test  all equipment and  processes so that  accurate
specifications can be made for the full-scale system.

Example 7 demonstrates the decision process to proceed
fromremedy screening, through remedy  selection, and on
to remedy design. This example  is a continuation  of
Example 4 on page 20.

The size and scope of the remedy design program may be
decided by several  factors including the  quantity  of
material available for testing, the complexity of the
process,  cost, time, and equipment  availability. An
important factor that should not be overlooked when a
remedy  design program  is being set up  is  that the
equipment must be sized so that realistic scale-up factors
can be used for going to full-scale operation.

In conclusion, technologies generally are evaluated first
at the remedy screening level and progress through the
remedy  selection  to  the remedy  design  level.  A
technology may enter, however, at whatever tier or level
is appropriate based  on available data on the technology
and site-specific factors. For example, a technology that
has been studied extensively may not  warrant remedy
screening  to determine whether it has the  potential  to
work. Rather,  it may go  directly  to remedy  selection
testing to verify that performance standards can be met.

                  Even though the reduction in PCP concentration during the  remedy screening study was
                  sufficient to justify continuing to the remedy selection tier of treatability testing, the percentage
                  of degradation, as compared to the control, indicated that process changes were needed at the
                  remedy selection tier. High PCP concentrations may have been inhibiting microbial activity. The
                  RPM decided to investigate mixing less contaminated soil with the highly  contaminated soil to
                  lower PCP concentrations and stimulate biodegradation. Remedy selection studies, using the
                  design modifications suggested by the remedy screening studies,  resulted in an average
                  removal of 93 percent of the PCP. Remedy design studies were performed to provide design
                  information for a full-scale system, which was used to remediate the site successfully.
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                                                  SECTION 7
        1.   American Society for Testing and Materials. 1987.
            Annual Book of ASTM Standards.

        2.   Box, G.E.P., W.G.  Hunter, and J.S. Hunter. Statistics
            for Experimenters. Wiley, 1978.

        3.   Gibson, D.T. Microbial Degradation of Organic
            Compounds. Microbiology  Series. Marcel Dekker,
            Inc., New York, 1984.

        4.   Kukor, J.J., and R. H. Olsen. Diversity of Toluene
            Degradation Following Long Term Exposure to BTEX
            In  Situ. In: Biotechnology and  Biodegradation.
            Daphne Kanely, A. Chakrabarty, and G. Omenn, eds.
            Gulf Publishing Co., Houston, Texas,  1989. pp. 405-

        5.   Lentner, M., and T. D. Bishop. Experimental Design
            and Analysis.  Valley Book Company, Blacksburg,
            Virginia, 1986.

        6.   Loehr, R-C. L and Treatment as a Waste Management
            Technology: An  Overview. Land  Treatment: A
            Hazardous Waste Management Alternative.  R.C.
            Loehr, et  al.,  eds.  Center  for Research in Water
            Resources, The University of Texas at Austin, 1986.
            pp. 7-17.

        7.   Marinucci,  A.C.,  and R.  Bartha. Apparatus  for
            Monitoring the Mineralization of Volatile 14C-Labeled
            Compounds.     Applied   and  Environmental
            Microbiology, 38(5): 1020-1022, 1979.

        8.   Munnecke, D.M.,  L.M. Johnson, H.W. Talbot, and S.
            Barik.  Microbial  Metabolism and Enzymology of
            Selected  Pesticides.  In:   Biodegradation   and
            Detoxification  of Environmental Pollutants. A.M.
            Chakrabarty, ed. CRC Press, Boca Raton, Florida,

        9.   Odeh, R.E. and M. Fox. Sample Size Choice. Marcel
            Dekker, Inc., New York, 1975.

        10.  Pramer,D., andR. Bartha.PreparationandProcessing
            of  Soil  Samples  for  Biodegradation  Studies.
            Environmental Letters, 2(4):217-224, 1972.
11.  Fitter, P., and  J. Chudoba, Biodegradability of
    Organic  Substances  in the Aquatic Environment.
    CRC Press, Boca Raton, Flonda, 1990.

12.  Reineke,  W., and  H. J. Knackmuss.  Microbial
    Degradation of Haloaromatics. Ann. Rev. Microbial.

13.  Ross, D. Application of Biological Processes to the
    Clean Up of Hazardous Wastes. Presented at The
    17th Environmental  Symposium:  Environmental
    Compliance and Enforcement at DOD Installations in
    the 1990's, Atlanta, Georgia, 1990.

14.  Sims, R. C. Treatment Potential for 56 EPA Listed
    Hazardous Chemicals In Soil. EPA/600/6-88/001, U.S.
    Environmental Protection Agency, 1988.

15.  U.S.   Environmental   Protection  Agency.  A
    Compendium of Technologies Used in the Treatment
    of Hazardous Wastes. EPA/625/8-87/014, 1987.

16.  U.S. Environmental Protection Agency. Engineering
    Bulletin: In Situ Biodegradation Treatment. EPA/
    540/0-00/000, unpublished.

17.  U.S. Environmental Protection Agency. Engineering
    Bulletin: Slurry  Biodegradation.  EPA/540/2-90/016,

18.  U.S.  Environmental  Protection Agency.  Guide for
    Conducting  Treatability  Studies Under  CERCLA,
    Intenm Final. EPA/540/2-89/058, 1989.

19.  U.S. Environmental Protection Agency. Methodsfor
    ChemicalAnalysis of Water and Wastes. EPA/600/4-
    79/020, 1979.

20.  U.S.   Environmental   Protection   Agency.
    Microbiological   Decomposition  of  Chlorinated
    Aromatic Compounds. EPA 600/2-86/090, 1986.

21.  U.S. Environmental Protection Agency, Preparation
    Aids for the Development of Category IV Quality
    Assurance Project Plans. EPA/600/8-91/006, 1991.

22.  U. S. Environmental Protection Agency. ROD Annual
    Report: FY 1989. EPA/540/8-90/006, 1989.
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        23.  U.S. Environmental Protection Agency. Technology    26. U.S. Environmental Protection Agency. Treatability
            Screening Guide for Treatment of CERCLA Soils and        Studies Under CERCLA: An Overview. Office of
            Sludges. EPA/540/2-88/004, 1988.                        Solid Waste and Emergency  Response, Directive
                                                                 9380.3-02FS, 1989.
        24.  U.S.   Environmental  Protection  Agency.   Test
            Methods for Evaluating Solid Waste. 3rd Ed., SW846,    27. 40 CFR, Section 796.3400.

        25.  U.S. Environmental Protection Agency. TestMethod:
            The Determination of Inorganic Anions in Water by
            Ion Chromatography -Method 300.0.
            EPA-600/4-84/017, 1984.
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