UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C 20460
E OF
ADMINISTRATOR
May 7, 1990 EPA-SAB-EEC-90-017
Honorable William K. Reilly
Administrator
U.S. Environmental Protection Agency
401 M Street, s.W.
Washington, D.C. 20460
Dear Mr. Reilly:
The Science Advisory Board (SAB) has completed its
research-in-progress review of the Office of Research and
Development's (ORD) Toxics TreatabiHty and Toxicity Reduction
(TT&TR) Research Program at the Risk Reduction Engineering
Laboratory (REEL), and is pleased to submit its final report. This
report resulted from a review meeting on June 22 and 23, 1989 at
which time Subcommittee members discussed the program with
representatives of ORD and from subsequent evaluations. The major
findings and recommendations of the Subcommittee's report are as
follows:
1) A Research Plan is Needed; The TTiTB, Research Program is
very important to the mission and responsibilities of the Agency.
However, the SAB found it difficult to properly review the TT&TR
Research Program, because of the lack of direction stemming from the
absence of an available research plan, A carefully constructed and
integrated research plan should be developed that clearly states the
program's objectives, goals and rationale.
2) teed for a Common and Prioritized List of Toxicants: The
biotic and abiotic fate data base should be greatly expanded,
primarily from the published literature. The data collection effort
and the program as a whole does not work off a common list of
toxicants* . To most effectively utilize resources, a common,
prioritized list should be developed and used to guide data
acquisition, experimental, and modeling efforts.
3) The Modeling Area NeedsA Directed. Critical Review: The
modeling work observed by the Subcommittee is not state-of-the-art.
If present modeling efforts continue, the modeling should be
augmented with personnel with greater expertise in Quantitative
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structure-activity relationships and transport and fate processes,
Existing models far integration and analysis of available data on
the fate of toxicants in wastewater treatment processes should be
critically reviewed and used where appropriate. The assistance of
other modeling groups within the EPA and of others with demonstrated
expertise in the field should be obtained. The in-house laboratory
research should be focused to talce advantage of special pilot
facilities for important projects, such as model verification. The
modeling efforts at RREL would benefit greatly from careful
consideration of the guidance given in the EPA/SAB model ing
resolution (EPA-SAB-EEC-89-012) .
4) A Peer. Hev_lew is Needed on All Bioassav and__Genotoxicity_
Test Methods Before ,,,_They ..are Broadly, ..... Applied ..... .tLQ_ wastewater ancj
Treatment Plant Effluents: The basic concepts used in the Toxic ity
Reduction Evaluation (TRE) program are sound, but need to be
developed further in order to cover the wide range of kinds of
wastes, treatment processes, operating conditions and local
circumstances. The procedures for characterizing, identifying and
applying current knowledge of genotoxins in municipal and industrial
wastewaters is so rudimentary that further data will be needed in
order to begin to refine protocols for TRE related to health
effects. Inappropriate use of toxicity tests can lead to false
credibility. To keep the TT&TR Research Program at a state-of-the
art level and on track, some type of regular external review should
be instituted.
5) A Substantial Technology Transfer; Program will be
Required: The effective use of TRE procedures in the field will
require that a substantial technology transfer program be put in
place.
These recommendations are made with the anticipation that the
RREL's TT&TR Research Program will be greatly improved in the
future, as the SAB views this program to be very important to the
fundamental mission and responsibilities of the Agency.
We are pleased to have had the opportunity to be of service to
the Agency, and look forward to your response on this report.
Sincerely,
Rayroondf c. Loehr, CttStiriaan Richard A. Conway, chairman
Executive Committee Environmental Engineering Committee
Science Advisory Board Science Advisory Board
Calvin H, Ward, Chairman
Toxics Treatability Subcommittee
Science Advisory Board
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PPA U,S. Environmental WatHJngton, DC
Crm Protection Agtncy EPA-SAB-EEC-iQ-017
Report of the Toxics
Treatability Subcommittee,
Environmental Engineering Committee
Review of ORD's Toxics Treatability
And Toxicity Reduction Research Program
A SCIENCE ADVISORY BOARD REPORT May 1990
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EPA-SAB-EEC-90-Q17
REPORT OF THE TOXICS TREATABILITY SUBCOMMITTEE
OF THE ENVIRONMENTAL ENGINEERING COMMITTEE
SCIENCE ADVISORY BOARD
REVIEW OF THE OFFICE OF RESEARCH AND
DEVELOPMENT'S TOXICS TREATABILITY AND TOXICITY
REDUCTION RESEARCH PROGRAM
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NOTICE
This report ^ has been written, as a part of the activities of
the Science Advisory Board, a public advisory group providing
extramural scientific information and advice to the Administrator
and other officials of the Environmental Protection Agency. The
Board is structured to provide a balanced, expert assessment of
scientific matters related to problems facing the Agency. This
report has not been reviewed for approval by the Agency; hence, the
comments of this report do not necessarily represent the views and
policies of the Environmental Protection Agency or of other Federal
agencies. Any mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
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ABSTRACT
The Toxics Treatability subcommittee (TTS) of the
Environmental Engineering Committee (EEC) of the EPA Science
Advisory Board (SAB) has prepared a Research-In-Progress report on
the Agency's Toxics Treatability and Toxicity Reduction (TTSTR)
research program. The goals of the TT&TR research program are to
develop protocols to 1) assess the fate of toxicants through
^astewater treatment plants, and 2) assess the integrated toxicity
of wastewater treatment effluents by use of selected bioassays.
The program is organized into three work areas; toxicants
treatability, toxicant modeling, and toxicity reduction
evaluations- The TT&TR research program is considered by the SAB
to be critically important in meeting National water quality goals
and to have many excellent elements.
The SAB's findings and recommendations relate to the program
research plan, toxicants treatability, toxicant modeling, toxicity
reduction evaluations and bioassay and genotoxicity testing.
Highlights of the SAB recommendations are that:
1) A carefully constructed and integrated research plan
should be developed,
2) A common and prioritized biotic and abiotic fate data
base and list of toxicants should be greatly expanded,
primarily from the published literature,
3) The modeling area needs a directed, critical review,
4) A peer review is needed on all bioassay and
genotoxicity tests before they are broadly applied to
wastewater and treatment plant effluents,
5) A substantial technology transfer program will be
required.
Kev Words; toxics treatability, toxicity reduction,
toxics treatability and. toxicity reduction research
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TOXICS TREATABILITY SUBCOMMITTEE
ENVIRONMENTAL ENGINEERING COMMITTEE
of the
SCIENCE ADVISORY BOARD
Ch.aJLnB.aa
Dr. Calvin H. Ward
Professor and Chairman
Department of Environmental
Science and Engineering
Rice University
Members and Consultants
Mr, George Carpenter
Michigan Department of
Natural Resources
Environmental Response Division
Dr, Ben 8* Ewing
Professor of Environmental Engineering
Institute for Environmental Studies
University of Illinois
Dr. Wayne Rachel
Senior Water Quality Engineer
Exxon Company, U.S.A.
or, Richard G. Luthy
Professor and Chairman
Department of civil Engineering
Carnegie-Mellon University
Dr. Paul V, Roberts
Professor of Environmental Engineering
Department of civil Engineering
Stanford University
Science Advisory Board Staff
Mail Address: Science Advisory Board (A101F)
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
official
Or. K. Jack KooYQom j ian
Staff . Secretary
Mrs. Marcy Jolly
Assistant Director
Mr. A. Robert Flaak
iii
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Director
Dr. Donald G. Barnes
chairman. Executive. Committee, Science
Advisory Board
Dr. Raymond C. Loehr
Department of civil Engineering
University of Texas at Austin
Chairman. Environmental Engineering
Committee
Mr. Richard A. Conway
Senior corporate Fellow
Union Carbide Corporation
IV
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TABLE QF_CONTENTS
1. 0 EXECUTIVE SUMMARY ............. 1
2 ,0 INTRODUCTION, , , 4
3 , 0 RESEARCH PLAN ...... 5
4 . 0 TOXICANTS TREATABILITY ... 7
4.1 Treatability Testing Procedures and Data for
Biodegradation in Conventional Wastewater
, Treatment...,.,,,,...... .......... 7
4.1,1 Aerobic .. * .. 7
4.1.2 Anaerob ie .. 8
4.2 Treatability Testing Procedures and Data
for Sorption and Volatilisation in
Conventional Wastewater Treatment. S
4.2.1 Sorption . 8
4.2.2 Volatilization. ....... 9
S . 0 TOXICANT MODELING 11
5.1 Inter-Laboratory Coordination and
Adaptation of Existing Models 11
5.2 Model organization......*,,.».,.............11
5.3 Model Validation..... 12
5.4 Model Sensitivity/Simplification .12
5.3 Resources for Model Development and
Validation. *. 12
6. 0 TOXICITY REDUCTION EVALUATIONS 12
6.1 Evaluation of TRE Protocols,,,,,,,.......,..13
5.2 Need for Technology Transfer System .. 13
6.3 Need for Realistic Expectations and
Continued Refinement of TRE Protocols.... 13
6.4 Status of Knowledge of Genotoxieity... ..14
6.5 Interpretation of Genotoxic TRE Results.....14
APPENDIX A - THE CHARGE TO THE SUBCOMMITTEE... 15
APPENDIX B - TOXICS TREATABILITY SAB SIGN-UP LIST OF
ATTENDEES/GUESTS, JUNE 22 AND 23, 198i...... 17
APPENDIX C - GLOSSARY OP TERMS * 19
APPENDIX D - RESOURCE MATERIAL AND REFERENCES CITED...20
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1.0 EXECUTIVE SUMMARY
A research in progress review of the Agency's Toxics
Treatability and Toxicity Reduction (TTSTR) Research Program was
conducted at the Risk Reduction Engineering Laboratory (RREL) on
22-23 June 1989 by the Toxics Treatability Subcommittee (TTS) of
the Environmental Engineering Committee (EEC) of the Science
Advisory Board (SAB). The stated objectives of the TT&TR Research
Program are to develop protocols to 1) assess the fate of
toxicants through wastewater treatment plants, and 2} assess the
integrated toxicity of wastewater treatment effluents by use of
selected bioassays. The program is organized into three work
areas: toxicants treatability, toxicant modeling, and toxicity
reduction evaluations. The TT&TR Research Program, considered by
the SAB to be critically important in meeting National water
quality goals, has many excellent elements. Some findings and
recommendations for improvement of the program follow.
1.1 Procrra.itL.Besearch Plan
The SAB found it difficult to properly review the TT&TR
Research Program because of the lack of an available research
plan. A carefully constructed and integrated research plan should
be developed that clearly states the Program's objectives and
goals, the rationale for each, the interactions and
interactiveness of program components, and the responsiveness of
the program to Agency and National needs.
The lack of an available research plan does not indicate that
the research that has been performed and is in progress is not
appropriate or worthwhile. However, since the SAB places such
great importance on this area of research and the topic is so
broad and interconnected with other Agency research and policy
making efforts, it is essential that there be a research plan for
the program to keep it focused and on budget.
1.2 Toxicants Treatabilitv
The SAB believes that past and ongoing biodegradation work on
single compounds, if properly analyzed and interpreted, will
suffice to support current program needs, and "that more laboratory
work in this area by the EPA should not be of high priority. The
treatability data base on single compounds should be expanded
based on data in the existing literature and updated as new
information is published* The fate of mixed substrates in
treatment processes should receive greater attention. Since the
RREL has unique capabilities in the Agency for pilot plant work
with mixed substrate raw wastewaters, the TT&TH Research Program
should, pursue mass balance studies for specific chemicals and
classes of chemicals including all applicable abiotic and biotic
fate mechanisms, not with the view of getting closure, but rather
to point the way to key mechanisms of removal * These studies
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should be complemented with suitable analyses for assessing
reductions in toxicity throughout the various stages of the
treatment processes being evaluated. Studies on the fate of
specific chemicals in mixed soluble substrates in aerobic
treatment systems seem appropriate; however, the fate of sorbed or
particle-bound toxicants should be given special emphasis in
anaerobic systems, since these processes are used mostly for
sludge digestion. The procedure of adding spiked compounds to
wastewater streams can lead to erroneous results, since the added
compounds may fail to enter into the waste matrix in a
representative fashion,
1.3 Toxicant Modeling
The RREL is developing a modeling approach for estimating
fate-in-treatment of organic toxicants in primary/activated sludge
wastewater treatment systems. It is understood that this model is
to be used by consultants and regulators for 1) guidance on how to
treat toxic organic compounds, and 2) guidance on whether RCRA and
CERCLA liquid streams may be disposed in a POTW. The modeling
effort, at the present time, is not intended to provide guidance
in the assessment or prediction of residual toxicity in POTW
effluents.
Some of the primary concerns of the SAB about current
modeling efforts in support of the TT&TR Research Program include
1) the need for assessment of the extent to which a new model
needs to be formulated versus the adaptation of existing, and
perhaps simpler, models, 2) the need for model confirmation and
sensitivity and uncertainty analysis, 3) the need for improved
coordination and interaction between process and transport and
fate scientists/engineers and modelers, 4) the serious need far-
peer review at an early stage of model development, and 5) the
adequacy of the data base on reaction rate constants.
TT&TR modeling efforts at RH1I» would benefit greatly from
careful consideration of the guidance on selection and use of
models given in the EPA/SAB modeling resolution (EPA-SAB-EEC-89-*
012). It also appears that existing, simple models could be
adapted, calibrated, and used for prediction of chemical fate in
wastewater treatment plants, if present modeling efforts
continue, the modeling team should be augmented with personnel
with greater expertise in quantitative structure activity
relationships and transport and fate processes. In addition,
immediate attention should be given to sensitivity analyses to
determine when, to what extent, and at what level each parameter
being considered influences or significantly affects the transport
and fate predictions for specific chemicals. Results of model
predictions, during early stages of model development, should be
compared to data obtained in parallel, coordinated pilot plant
experiments in the toxicants treatability research initiative.
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A directed, critical review of existing models that could be
used for toxicant modeling should be undertaken immediately by
those skilled in the art. Current in-house and contractor
expertise at RREL in modeling appears inadequate to support the
needs of the TT&TR Research Progran.
1.4 Toxicity Reduction .Evaluations
The objective of the Toxicity Reduction Evaluations (TRE)
area is to determine the toxieity of wastewaters before and after
treatment in order to determine the reduction in toxicity by
treatment processes and thereby to devise ways to adjust the
treatment processes (or influent waste streans through elimination
or pretreatment to remove specific types of contaminants not
effectively treated) or incorporate additional treatment processes
to achieve toxicity reduction goals. The general Methodology
involves use of bioassays for determining the toxicity of complex
mixtures of organic compounds and/or metals which contribute to
the toxicity without chemical analysis of specific elements or
compounds. The basic concepts used in the TRE program are sound,
but need to be developed further in order to cover the wide range
of kinds of wastes, treatment processes, operating conditions, and
local circumstances at operating publicly-owned treatment works.
The protocols for Toxicity Identification Evaluation (TIE)
developed by the EPA Duluth Laboratory seem appropriate for use in
assessing and identifying sources of toxicity in the TRE program.
The procedures for characterizing an
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2.0 INTRODUCTION
A. research in progress review of the Agency's Toxics
Treatability and Toxicity Reduction (TT&TR) Research. Program was
conducted at the Risk Reduction Engineering Laboratory (HREL) on
22-23 June 1989. The review was conducted by the Toxics
Treatability Subcommittee (TTS) of the Environmental Engineering
Committee (EEC) of the Science Advisory Board (SAB). Extensive
written documentation on the program's projects was provided to the
Subcommittee as background before the review (Appendix D). The
format for the review consisted of 1-1/2 days of formal
presentations by laboratory and program management and by both
in-house and contractor technical personnel, followed by informal
discussions which included representatives from EPA headquarters in
Washington, D.C. (Appendix B).
ProgramGoalsand Tasks
RREL Director Mr. E. Timothy Gppelt opened the review by
succinctly stating that the goals of EPA's TTiTR Research Program
are to:
(1) Assess the fate of toxicants through wastewater treatment
plants, and
(2) Assess the integrated toxicity of wastewater treatment
effluents by use of selected bioassays,
To accomplish these goals, the program is currently organized
into three major work areas:
(1) Toxicants Treatability - development of experimental
protocols for and generation of relevant data on the
abiotic (sorption and volatilization) and biotic (aerobic
and anaerobic bi©degradation) components of the fate of
toxicants in biological wastewater treatment processes.
(2) Toxicant Modeling - development of a modeling approach for
estimating fate-in~treatment of organic toxicants in
primary/activated sludge wastewater treatment plants based
on experimental data and the chemical and structural
molecular properties of toxicants.
(3) Toxigity Reduction Evaluations - development of protocols
for a) systematically conducting Toxicity Reduction
Evaluations at municipal and industrial wastewater
treatment plants to determine the efficacy of the
treatment process, and b) Toxicity Identification
Evaluations to separate and identify the sources
(discharges) of toxicity to wastewater treatment plants.
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Information and evaluation tools are intended to provide
support for regulatory decisions on;
(1) Pretreatment requirements for specific toxicants and
wastewater treatment plant effluent toxieity,
(2) Treatment needs for wastewater discharges into "open"
oceans,
(3) Water quality suitability of aqueous discharges from
treatment, storage and disposal facilities (TSDF) used in
controlling listed aqueous RCRA wastes,
(4) Banning or restricting production of new or existing
chemicals, and
(5)' Efficient use of waste minimization and waste prevention
techniques to support the national initiative on pollution
prevention through identification of specific industrial
sources of toxicants and/or toxicity.
one highly visible, immediate need for output from this program
was voiced in question form by a representative of the EPA Office of
Water Programs; "Can I take a liquid stream from a Superfund Site
and put it into a wastewater treatment plant?" The fact that extant
knowledge on the fate of toxicants in wastewater treatment
processes, after decades of study and operation, is inadequate to
provide acceptable guidance on this question, clearly demonstrates
the need for appropriate effort in the Agency on Toxics Treatability
and Toxicity Reduction.
3.0 RESEARCH PLAM
The SAB-EEC Toxics Treatability Subcommittee (TTS) was hindered
in this review of the TT&TR Research Program by the lack of an
available Research Plan. Without the plan, it was difficult to
assess how the research projects that were presented would be
utilized to satisfy the program goal: to assess the fate of
toxicants and their toxicity through wastewater treatment.
For example, it was not clear if the Toxicity Identification
Evaluation (TIE) work was intended to supplant the toxics
treatabillty laboratory studies. The toxics treatability studies
are compound specific and deal only with single compound situations,
while the TIE work deals with a characteristic that may be exhibited
by a wastewater. While it is true that a toxic compound will
exhibit the characteristic of toxicity, in the real world it is
difficult, if not impossible, to break down the toxicity
characteristic into its component parts. That being the case, it
seems only logical that more attention needs to be paid to
identifying those compounds that contribute to the toxicity of a
given wastewater. Further, how do the TIE and Toxicants
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Treatability efforts fit into the Research Plan?
. Likewise, it was unclear how a compound-specific mathematical
model relates to the TIE work. The fate of compound Hx" through a
wastewater treatment plant is only of academic interest. The real
issue is how does the toxicity of a complex wastewater decrease
through wastewater treatment?
This is not to say that the research that has been performed
and is currently underway is not worthwhile. This is an extremely
important research area that is well worth the Agency's effort.
However, since the research topic is so broad and there are so many
significant interactions both within this program and with other
Agency research and policy making efforts, it is essential that
there be a research plan for the program to keep it focused and on
budget,
A research plan is a roadmap and as such has many ber.afits, not
the least of which are:
•establishing resource needs,
•setting priorities,
•delineating interactions, and
»setting milestones.
The first step in developing a research plan is to clearly
identify the objectives. At several times during the review,
various TTS members asked what the objective of the research was.
Rather than a succinct statement that the presented research was
designed so that it would be used for a specific purpose, several
ill-defined and hypothetical uses for the work were presented in a
fashion that gave the impression that they were developed after the
fact to justify, having done the research.
It is imperative that program priorities be firmly established.
During the discussion of treatability protocols, RRSL staff
indicated that they were hindered by the lack of available precise
analytical tools, yet they plan to continue developing treatability
data for various compounds. If they cannot adequately monitor what
is taking place in their reactors, then they should cease all future
treatability testing until they can measure the necessary parameters
to an appropriate level of precision that would allow them to be
confident of the quality of the data. Methods development needs
to be the top priority. This goes for both analytical procedures as
well as bioassay/TRE methodologies.
This program cuts across several Agency efforts and must be
coordinated with them in order to avoid duplication of effort and
thus the wasting of valuable Agency resources. At a minimum, it
should be made clear how the derived information relates to past,
current, and planned initiatives in the areas of pollution
prevention, air toxics, solid waste, drinking water standards, water
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pollution control and model development.
An effective research plan needs to be a dynamic document that
is frequently updated at appropriate intervals in response to
changes in Agency budgets and priorities. It is acknowledged that
national environmental priorities will constantly change and with it
the Agency's focus. The program needs to adjust accordingly.
Having a research plan in place will allow this research effort to
be assigned its rightful priority when it comes time to allocate the
Agency's resources.
Once a plan has been developed, it may become evident that
significant additional resources must be obtained in order to attain
stated objectives by agreed-upon times. This is important to know
during the annual budgeting process. For example, adjustments
appear to be needed in the research effort to assess mutagenicity
caused by chlorinating wastewater effluents. If chlorination does
make a wastewater more mutagenic, then a well-documented decision
must be made as to what additional work must be undertaken to
address the problem.
Another factor that must be given consideration in the research
plan is how toxicity should be defined for the purpose of this
research. It is apparent that different materials are toxic to
different organisms in different concentrations under different
conditions. If this research is to focus on toxicity, as the title
implies, then a consistent set of toxicity standard measurements
should be established to interrelate the projects. Is the objective
to reduce toxicity to humans, to selected invertebrates, or to all
living organisms? This is a difficult question, but one that must
be resolved so that the research can serve as a useful guide for
policymakers.
4.0 TOXICANTS TREATABILITY
4.1 Treatability Testing Procedures and Data for Biodeqradation_in
conventional Wastewater Treatment
4.1.1 Aerobic
The aerobic biodegradation work on single compounds done both
in-house and by RREL contractors has resulted in a useful data base
on a limited number of chemicals. The approach has been to develop
biodegradation protocols that will yield intrinsic kinetic
parameters that are independent of the system and bioraass
concentration. However, kinetic parameters for specific chemicals
in treatment processes will be influenced by the type and
physiological state of the biota present and by interactions
between chemicals in complex mixtures.
The contractor effort in this area to date has been excellent.
Past and ongoing biodegradation work on single compounds, if
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properly analyzed and interpreted, will suffice to support
needs. Future efforts on single compounds should be directed
primarily to greatly expanding the available data base by review and
analysis of existing literature. Expansion of the data base for all
fate mechanisms should be focused by development of a common,
prioritized list of toxicants,
Since the RjREL has unique capabilities for pilot plant work and
the ultimate objective of the TT&TR Research Program is to assess
and predict the fate of single compounds in complex mixtures in
wastewater treatment, future in-house biodegradation research should
be conducted with mixed substrates at pilot plant scale. Both
biotic and abiotic fate parameters should be evaluated in
coordinated studies where a mass balance approach is used.
4.1 ...,2 Anaerobic
Low solubility organic compounds tend to sorb and partition to
biomass solids during conventional aerobic wastewater treatment
processes* Depending on the compound, degradation may be
incomplete or may not occur. Hence, significant quantities of toxic
organics may be removed, from the process in wasted activated sludge
solids that require further treatment before final disposal.
Anaerobic biodegradation work currently in progress by contract
in support of the TT&TR Research Program is expertly done; however,
the protocol employed focuses on soluble substrates and does not
simulate actual conditions. Hence, future anaerobic degradation
work should be done on particle-bound toxicants to simulate
anaerobic sludge digestion. Data collected to date will be useful
for predicting the fate of toxicants in processes such as sequencing
batch reactors but will be of limited use in assessments of
conventional wastewater treatment processes.
In both aerobic and anaerobic biodegradation work, caution is
urged in the use of spiked toxicants. If the experimental protocol
does not assess the physical state of the spiked chemical in the
test system, the assumption that the toxicant has entered into the
waste matrix in a manner similar to actual waste streams may be
erroneous. Since sorption strongly influences bioavailability,
overestimates of biodegradability can result,
4 .2 Treatabilitv Testing: Procedures and Data for Sorptlon and
Volatilization in Convent.i.o_tial Wastewafcer Treatment.
4.2.3, Sorption
This work is being performed to provide information on abiotic
processes affecting removal of organic constituents in wastewater
treatment systems. The results from this work will be used for
modeling individual removal mechanisms in primary/activated sludge
wastewater treatment systems. The sorption studies are focusing on
8
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the partitioning of organic compounds onto activated sludge
microbial solids.
The present research would benefit from close examination of
studies of similar scope on sorption of hydrophobie solutes onto
microbial solids and/or soil. Various other research groups have
examined sorption of hydrophobia organic solutes onto microbial
solids, and this information should be synthesized and interpreted
with regard to the results from the current laboratory measurements,
This will help confirm the degree of commonality and conformity
among the data bases. Also, this integration of experimental
results may suggest that sufficient data currently exist for
modeling purposes to estimate sorption partitioning of hydrophobic
solutes onto microbial solids.
Likewise, the large amount of information on sorption of
hydrophobic compounds onto soil is potentially very useful for
assessing the extent to which soil-sorption correlations are
applicable to microbial solids as well, current evidence suggests
that it may be reasonable to assume that equilibrium sorption
partitioning of hydrophobic organic solutes onto bio-solids is
analogous to partitioning on soil. For these reasons the current
laboratory effort should be focused to determine the connections
between the recent laboratory results and the other data bases.
The soil sorption literature also provides an explanation for
the "solids effect", and discusses the need to be concerned for
separation of suspended micro-particulate matter in order to attain
reliable laboratory estimates of the partition coefficient for very
hydrophobic (high K0(t) solutes. Also, longer equilibration times
may be warranted for very hydrophobic solutes than indicated by
screening tests for more polar solutes (e.g., methylene blue).
It has been demonstrated for soil suspensions that hydrophobic
solutes at low concentrations (e.g., the lesser of about 1 mg/L or
one-half aqueous solubility) sorb independently from solute
mixtures. This should be evaluated for microbial solids, as
modeling and predictions would then be simplified.
An evaluation should be performed in order to understand the
effect of wastewater treatment plant effluent containing
surface-active material on solute sorption. The objective of this
work should be viewed as a screening assessment designed to answer
the question of whether there is any significant effect on sorption
of hydrophobic compounds owing to aqueous-phase organic byproducts
from microbial treatment. A careful literature compilation would
suggest the degree of experimentation which may (or may not) be
warranted,
4._g_.,2 Volatilization
The volatilization studies should be directed towards
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validating a modeling approach'for integrating the contribution of
volatilization on removal' in primary/activated sludge treatment
processes. For this reason, well-controlled laboratory experiments
are probably best used to compare the potential influence of
wastewater matrix effects in relation to clean water results and to
examine biooxidation-sorption-volatilization rate constants under a
competitive mode, in general, for volatile solutes (KH>10"<*
atm-a/mole) the wastewater matrix effects may not be significant
with respect to guasi-equilibrium partitioning between gas and
,iguid phases. However, surface-active material present in
wastewater may affect the rate of mass transfer for certain vocs
during aeration in activated sludge processes. This and other
issues related to VQC removal in activated sludge facilities may be
addressed by literature assessment and by a few, well-designed pilot
plant studies.
The research plan for the TTiTR Research Program should address
the proportionality of rate transfer coefficients between selected
VOC and dissolved oxygen* In this manner it may be determined if
the transfer rates of dissolved oxygen and organic solutes are
inhibited approximately to the same degree. Current research
suggests this may be the case, and this simplifies modeling. The
research should also assess whether gas-phase saturation has an
effect on mass transfer from water to air under conditions of
activated sludge treatment? this assessment-should take into account
the differences between mechanical surface aeration and bubble
aeration. These issues should be addressed first by synthesis of
available literature and, if necessary, modeling to identify which,
if any, classes of compounds are sensitive to these issues.
The RREL has unique capability to perform the necessary fate
and transport studies with a pilot test and evaluation facility
located in Cincinnati, Ohio. Therefore, to the extent possible, it
is recommended that research on volatilization of VOCs be
incorporated with validation of the modeling approach for
integrating removal mechanisms. This work would provide the dual
benefit of aiding model verification, while suggesting a focus for
laboratory-based volatilization studies through reconciliation of
departure between prediction and observation.
The in-house laboratory research at REEL is characterized
partly by the execution of repetitive measurements to identify
compound properties. In this regard, the IRJEIt is cautioned to
prevent its experimental research from becoming preoccupied with
routine measurements directed towards developing "more points along
the curve". The in-house laboratory research should be focused to
take advantage of special pilot facilities for important projects
such as model verification.
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5.0 TOXICANT., MODELING
The TT&TR Research Program has developed a modeling approach
for estimating fate-in-treatment of organic compounds in
primary/activated sludge wastewater treatment systems. It is
understood that this model is to be used by consultants and
regulators for: 1) guidance on how to treat toxic organic compounds,
and 2) guidance on whether RCRA, CIRCLA and industrial liquid
streams may be disposed to a POTW.
This modeling effort was the subject of extensive discussion by
the Toxics Treatability Subcommittee. Some of the principal
concerns include: the need for assessment of existing, and perhaps
simpler, models," the need for confirmation and sensitivity and
uncertainty analysis; the need for improved coordination and
guidance; and the need for peer review,
5. i inter-Laboratory...Coordination and...._Adaptation of Existing Models
Various laboratories within the EPA have expertise on
development of models to aid prediction of fate and transport of
organic compounds. Such models are intended for use by regulators
and engineers/scientists. This modeling expertise within the EPA
apparently has not been consulted for this project. This expertise
may help prevent duplication of effort, as certain components of the
model may already exist elsewhere. Indeed, a useful subcomponent
model on VOC emissions for an integrated model has been supported by
the RHEL, but apparently not acknowledged as being employed in the
model.
A directed critical review of existing models needs to be
undertaken. Other academic and industrial research groups have been
working on fate-in-treatment models, and this body of work needs to
be consulted in order to determine the extent to which a new model
needs to be formulated versus the adaptation of existing, and
perhaps simpler, models.
5.2 Model Organization
The fragment constant and group contribution approach for
predicting biological degradation rate is interesting, but not
sufficiently advanced for inclusion in a general-purpose model.
Existing information on toxicant degradation rate constants in
activated sludge wastewater treatment needs to be compiled and
evaluated. The selection of microbial degradation rate parameters
in the model should include the versatility to utilize appropriate
literature-based rate constants in the forms proposed by the
original investigators. It is overly optimistic to presume that a
simple, self-consistent data base will suffice for this purpose.
Therefore, the modeling approach should permit flexibility for
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extraction of appropriate degradation rate constants (i.e., first-,
zero-, and mixed-order). Model confirmation, sensitivity and
uncertainty analysis will indicate those compounds and rate
constants for which the data base may be consolidated, as well as
indicate where the data base is particularly weak.
5._3 ' Model Validation
The model being used in the TT&TR Program is not validated with
respect to: 1) EPA REEL pilot plant data, 2) other IPA treatment
system data such as the 1982 "40 POTW Study", 3} other field data
such as the Chicago MSD and the Seattle metro studies, and 4) other
proposed models for either overall fate-in-treataent or submodels
for specific processes.
5.4 Model Sensitivity/Simplification
As part of the model verification process, the fate-in-
treatment model needs to be tested with various data bases, and
assessed in comparison with other proposed models. In this way, the
fate-in-treatment model will be evaluated for completeness and
inadequacies. This will also provide an appropriate set of case
studies to educate potential users on the overall utility of the
approach.
5._5 Resources for Model Development and Validafcjojn
It appears that the fate-in-treatment model is intended to be
one of the principal products of the "toxics treatability" research,
However, this model seems to be under-emphasized in terms of
programmatic focus and under-funded in terms of available resources.
The fate-in-treatment model is inadequate in its present fora.
Consideration should be given to allocating this project to a group
or team that has expertise in treatment plant operations, as well as
being specifically accustomed to the protocols and concerns for
development of general-use software for environmental fate
assessment. More resources may have to be directed to this task.
6.0 T-QXICITY REDUCTION EVALUATIONS
The Subcommittee reviewed three documents which describe the
protocols for Toxicity Reduction Evaluations (TRE). These include
the Toxicity Reduction Evaluation Protocol for Municipal wastewater
Treatment Plants (EPA/SQO/2-S8/Q62), the Generalized Methodology for
Conducting Industrial Toxicity Reduction Evaluations
(EPA/600/2-88/070), and the report by Christian and Cody entitled,
"Cytotoxicity and Mutagenesis Methods for Evaluation of Toxicity
Removal from Wastewaters."
The objective of TRE is to determine the toxicity of
wastewaters before and after treatment in order to determine the
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reduction in toxieity by treatment processes which remove toxic
substances and thereby to devise ways to adjust the treatment
processes or incorporate additional treatment processes which will
remove more of the toxicity. The general methodology involves use
of bioassays for determining the toxicity of the complex mixture of
organic compounds and/or metals which contribute to the toxicity
without chemical analysis of specific elements or compounds. The
protocols use Toxieity Identification Evaluation (TIE) procedures.
After the toxicity source is evaluated, then source reduction or
modifications in the pretreatment processes can be investigated with
the aim of toxicity reduction. The industrial TREs also put great
emphasis on investigation of housekeeping practices because of their
importance in toxicity reduction.
6,. 1 Evaluation of TR1 Protocols
The basic concepts presented in all of the TRE protocols
reviewed are sound. However, further development is needed in
order to cover the wide range of kinds of wastes, treatment
processes, operating conditions, and local circumstances. in
particular, the procedures for characterizing and identifying
genotoxic substances and location of their sources need further
development. Current knowledge of genotoxins in municipal and
industrial wastewaters is so rudimentary that further data will be
needed in order to begin to refine the protocols for TRE involving
this kind of toxicity.
6.2 Reed for Technology Transfer System
Basically, TRE is detective work; it. requires use of very
knowledgeable personnel to search for the identities and sources of
very elusive substances. Like much detective work, the user must
have an intimate knowledge of the system and the basic principles
which control its behavior. Otherwise, one may be misled in the
toxicity evaluation. But detective work is usually a mixture of
science and intuition. TRE procedures seem to be no exception. One
danger is that if these protocols are turned over to persons who are
not highly competent waste treatment professionals, they may not
lead successfully to location of the sources of toxicity and to
devising methods of reduction. As a professional gains experience
with TREs, intuition may very well sharpen. In order that each
person does not have to labor through the experience, or
"school-of-hard-knocks11, individually, a good technology transfer
system should be established so TRE detectives can learn from
others' experience as well.
JLtl Need for Realistic Expectations and, Continued Refinement of TIE
Protocols
A second, and probably greater, danger is that sources of toxic
substances cannot be identified because the toxics are ubicftiitous or
are from such disparate sources that a single source cannot be
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isolated. This might occur if a community has many similar
industries producing similar mixtures of toxic substances as, for
example, a metal plating center or a petrochemical industrial park.
This does not obviate the need for the proposed TRE procedures, but
it suggests the importance of realistic expectations and the
benefits of further refinement of techniques gained with experience.
6.4 Status_of Knowledge of Genotoxicity
Genotoxin TREs are in the rudimentary stage of development, we
agree with the TT&TR Research Program that genotoxic assessment
cannot be used for human health risk assessment, because there is no
known way with mixtures to link a genotoxic response in a bioassay
using lower target organisms to mutagenic or carcinogenic response
in humans and the probability of adverse health effects in a human
population. The protocol proposed by the TT&TR Research Program is
to use genotoxic bioassays to identify wastes which contain
genotoxins and those which do not, so that the source of the
autagens can be identified. It is hoped then that the waste from
the individual source can be characterized to pinpoint the few
suspect mutagenic compounds. Only if adequate epidemiological data
are available for these compounds can a human health risk assessment
be completed for the specific compounds or mixture of compounds.
Nevertheless, the genotoxicity faioassays are useful in evaluating
f.ate~in-treatment and reduction in genotoxlcity by treatment or
pretreatment modifications.
The use of a variety of different organisms with different
genotoxic endpoints in the bioasaay is very good. The proposed
protocols use the Ames/Salmonella assay, which tests for reverse
mutations in bacteria, and induction of sister chromatid exchange in
Chinese hamster ovary cells. As more is learned about genotoxic
properties of wastes and the genotoxic TREs are refined, other
bioassays to identify mutagens which produce forward mutations or
frame-shift mutations might be added to the bioassay procedures.
6_._5 Interpretation of Genotoxic TRE Results
Wastewater treatment professionals and environmental
toxicologists in general are not adequately familiar with genotoxins
in wastes? few are able to interpret results of bioassays for
mutagenic activity with any confidence. Most do not know what a
specified number of revertants reported in an Ames assay means.
They have no frame of reference witti which to compare it. For this
reason, it would be helpful if EPA took steps to determine from the
existing literature the mutagenic activity of some common substances
for comparison. As results of comparable mutagen assays for
drinking water, for surface waters, for common household exposure,
etc. are published, these comparisons will facilitate interpretation
of bioassays. Then the TRE personnel can know better which tests
have priority for further follow-up.
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APPENDIX A - THECHARGE TO THE SUBCOMMITTEES
SCIENCE ADVISORY BOARD
REVIEW OF THE
TOXICS TREATABILITY AND TOXICITY REDUCTION PROGRAM
The Toxics Treatability and Toxicity Reduction Program in the
Risk Reduction Engineering Laboratory (REEL) is developing
evaluation tools to support the Agency's regulatory decision
processes for management of specific aqueous wastes. The
evaluation tools include;
• Experimental protocols and data on representative
toxicants for evaluating treatability (biodegradation,
inhibition, sorption, and volatilization) in biological
wastewater treatment processes,
Experimental data on fate-in-treatment of representative
toxicants for the primary/activated sludge process and for
alternate wastewater treatment systems,
A model for estimating fate-in-treatment of organic
toxicants from their chemical and structural molecular
properties in primary/activated sludge treatment.
* Case history experimental data for the control of effluent
toxicity from municipal and industrial wastewater
treatment plants.
Protocols for systematically conducting Toxicity Reduction
Evaluations (TRls) at municipal and industrial wastewater
treatment plants.
These evaluation tools provide support for regulatory
decisions am
« Pretreatment requirements for specific toxicants and
effluent toxicity.
Treatment needs for wastewater discharges into "open"
oceans *
Water quality suitability of aqueous discharges from
treatment storage and disposal facilities (TSDF) used in
controlling listed aqueous RCRA wastes.
Banning or restricting production of new or existing
chemicals.
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• The efficient -use of waste minimization or waste
prevention techniques through identification of specific
industrial sources of toxicants and/or toxicity.
The Science Advisory Board in its review of the toxics
treataMlity and toxicity reduction program is specifically
requested to evaluate:
• The approaches and methods used or planned in the
experimental treatability protocol developed for
evaluating aerobic and anaerobic treatability of toxicants
in wastewater, and the need for expanded fate-in-treatment
data on toxicants in biological wastewater treatment.
The approaches used for studying and modeling individual
removal mechanisms (biodegradation, sorption and
volatilization) in primary/activated sludge wastewater
treatment, and the modeling approaches for integrating the
individual mechanisms into an overall toxicant fate-in*
treatment model.
» The level and quality of data needed to establish a
satisfactory model for estimating fate-in-treatment of
toxicants in primary/activated sludge processes for (a,)
overall guidance assessment, and (b) treatment plant
specific decisions.
The TR1 approaches for municipal and industrial wastewater
treatment plants, including the planned TRE health effects
study.
The distribution of available resources in the research
program.
The board is requested to provide recommendations for improving
the toxics treatability and toxicity reduction program including
specific recommendations am
The appropriateness of developing fate-in-treat»ent
predictive capabilities for the two application areas
described above.
The technical soundness of the TRE nealth effects study
and possible alternative approaches.
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APPENDIX B - TOXICS TREATABILITY 5AB SIGN-UPLIST OF ATTENDEES/
GUESTS, JUNE 22 AND 23, 1989
Toxics Treatability SAB Sign-Up List
Attendees/Guests, 22 June 1989
Name
Jack Kooyoomjian
Wayne Kachel
Richard G. Luthy
E, Timothy Gppelt
Clyde J Dial
Manuel P. Del Pino
Kuyen Li
Sheila L. Rosenthal
Rakesh Govind
Richard A. Dobbs
Fred Bishop
Alden Christiansen
Sid Hannah
James C. Young
Ben B, Swing
C. H. Ward
Henry H. Tabak
Yonggui Shan
Eric Cohen
Atal Eralp
Ruth Lopez
James M. Lelee
William Clement
Michael Jelus
Richard Brenner
C. P. Leslie Grady, Jr.
B. Daniel
John Meier
Affiliation/Address
SAB Staff/EPA HQ
Exxon, Benicia, CA (SAB)
Carnegie Mellon University (
EPA-RREL
EPA-RHEL
Union carbide Corp.
Lamar University
EPA-QHEA
University of Cincinnati
EPA-WHWTRD REEL
EPA-WHWTRD RREL
EPA-WHWTRD RREL
EPA-WHWTRD RREL
University of Arkansas
University of Illinois (SAB)
Rice University (SAB)
EPA-WHWTRD RREL
EPA-WHWTRD RREL
EPA, OKPC-Washington, DC
EPA, QMPC-Washington, DC
OWRS/EPA HQ
E, G. Jordan, Portland, ME
Battelle, Columbus
EPA-RREL/TAB, Cincinnati
EPA-RREL/fAB, Cincinnati
Clemson University
IPA-HERL
EPA-HERL
SAB)
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Toxics Treatability SAB Sign-up List
Attendees/Guests, 23 June 1989
Jack Kooyoomjian SAB Staff/EPA HQ
Kuyen Li Lamar University
Fred Bishop EPA-RREL
John Meier EPA-H1RL
c. H. Ward Rice University (SAB)
Richard A, Dobbs RREL
James c» Young University of Arkansas
Yonggui Shan EFA-RREL
Richard G. Luthy carnegie Mellon University
Wayne M. Kachel Exxon (SAB)
Eric Cohen EPA-OMPC Washington, DC
Ruth Lopez EPA-OWRS HQ Washington, DC
Bernie Daniel SPA-HERL
Ben B. E«dng University of Illinois (SAB)
Atal Eralp EPA-OW-OMPC
Clyde J. Dial EPA-RREL
E. Timothy Oppelt EPA-RREL
Alden Christianson EPA-RREL
Henry H. Tatoak EPA-RR1L
Kathy S. Clench EPA-HERL
Sheila F. Rosenthal EPA-OHEA
Trent R. Lewis Consultant, Cincinnati, OH
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APPENDIX C - GLOSSARY OF TERMS
ACS- AMERICAN CHEMICAL SOCIETY
AWMA- AIR AND WASTE MANAGEMENT ASSOCIATION
CERCLA- COMPREHENSIVE ENVIRONMENTAL RESPONSE, COMPENSATION AND
LIABILITY ACT, or (SUPERFUND)
EEC- ENVIRONMENTAL ENGINEERING COMMITTEE OF THE SCIENCE
ADVISORY BOARD OF THE U.S. ENVIRONMENTAL PROTECTION
AGENCY
EPA- U.S. ENVIRONMENTAL PROTECTION AGENCY (ALSO USEPA)
EPA/OMPC- U.S. ENVIRONMENTAL PROTECTION AGENCY/OFFICE OF MUNICIPAL
POLLUTION CONTROL PROGRAMS
EPA/OW/
QMPC- US. ENVIRONMENTAL PROTECTION AGENCY/OFFICE OF
WATER/OFFICE OF MUNICIPAL POLLUTION CONTROL
EPA/OWRS- U-S- ENVIRONMENTAL PROTECTION AGENCY/ OFFICE OF WATER
REGULATIONS AND STANDARDS
HERL/Ci- HEALTH EFFECTS RESEARCH LABORATORY, CINCINNATI, OHIO
OF THE U.S. ENVIRONMENTAL PROTECTION AGENCY
HQ- HEADQUARTERS OF THE EPA, WASHINGTON, D.C.
I&EC- INDUSTRIAL AND ENGINEERING CHEMISTRY DIVISION, INC- OF THE
AMERICAN CHEMICAL SOCIETY
JWPCF- JOURNAL OF THE WATER POLLUTION CONTROL FEDERATION
MSD- METROPOLITAN SANITARY DISTRICT
OHEA- OFFICE OF HEALTH AND ENVIRONMENTAL ASSESSMENT OF THE
OFFICE OF RESEARCH AND DEVELOPMENT, U.S. ENVIRONMENTAL
PROTECTION AGENCY
OMPC- OFFICE OF MUNICIPAL POLLUTION CONTROL OF THE U.S.
ENVIRONMENTAL PROTECTION AGENCY
QRD- OFFICE OF RESEARCH AND DEVELOPMENT OF THE U.S.
ENVIRONMENTAL PROTECTION AGENCY
PQTW- PUBLICLY OWNED TREATMENT WORKS
RCRA- RESOURCE CONSERVATION AND RECOVERY ACT
REEL- RISK SEDUCTION ENGINEERING LABORATORY OF THE U.S.
ENVIRONMENTAL PROTECTION AGENCY
REEL/TAB,
Ci- RISK REDUCTION ENGINEERING LABORATORY/TREATMENT
ASSESSMENT BRANCH, OF THE EPA, CINCINNATI, OHIO
SAB- SCIENCE ADVISORY BOARD OF THE U.S. ENVIRONMENTAL
PROTECTION AGENCY
TAPPI- TECHNICAL ASSOCIATION OF THE PULP AND PAPER INDUSTRY
TIE- TOXICITY IDENTIFICATION EVALUATION
TRE- TOXICITY REDUCTION EVALUATION
TSDF- TREATMENT, STORAGE AND DISPOSAL FACILITIES
TTS- TOXICS TREATABILITY SUBCOMMITTEE OF THE ENVIRONMENTAL
ENGINEERING COMMITTEE OF THE SCIENCE ADVISORY BOARD
(ALSO REFERRED TO AS THE SUBCOMMITTEE)
TT&TR- TOXICS TREATABILITY AND TOXICITY REDUCTION
VQC- VOLATILE ORGANIC CARBON
WHWTRD- MATER AND HAZARDOUS WASTE TREATMENT RESEARCH DIVISION OF
THE RISK REDUCTION ENGINEERING LABORATORY OF THE U.S.
ENVIRONMENTAL PROTECTION AGENCY
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APPENpIX D - RESOURCE MATERIAL AND REFERENCES CITED
1) Battacharya, Sanjoy K, et al, rate and Effects of Selected RCRA
and CERCLA Compounds in Activated Sludge Systems, Presented at
the 15th Annual EPA Research Symposium: Remedial Action,
Treatment and Disposal of Hazardous Waste, April 10-12, 1989,
in Cincinnati, Ohio
2} Battelle, TRE Industrial Protocol - case Histories, Briefing
Presented to the Science Advisory Board, Toxics Treatability
Subcommittee, June 22, 1989, 35 pages
3) Botts, John A. et al, Toxieity Reduction Evaluation at the
Patapsco wastewater Treatment Plant, IPA/600/2-88-034,
NTISIPB88-22Q488/AS, June 1988
4) Botts, John A, et al, Toxicity Reduction Evaluation Protocol
for Municipal wastewater Treatment Plants, EPA/600/2-88-062,
April 1989
S) Case Study, Toxicity Reduction Evaluation at the Patapsco Waste
Water Treatment Plant, Baltimore, MD, Presentation to the
Science Advisory Board, June 22, 1939, 46 pages
6) Christian, Robert and Terence Cody, cytotoxicity and
Mutagenesis Methods for Evaluating Toxicity Removal from
Waste-waters, contract #68-03-2846, W.A. 2846-17, 1989
7} Dang, Jasvinder S., 0.M. Harvey, A. Jobbagy and C.P.L. Grady,
Jr., Evaluation of Biodegradation Kinetics with Respirometric
Data, Presented at the 61st Annual Conference of the WPCF,
October 2-6, 1988, Dallas, Texas
8) Dobbs, Richard A, et al, Fate and Effects of RCRA and CERCLA
Toxics in Anaerobic Digestion of Primary and Secondary sludge,
Presented at the 15th Annual EPA Research Symposium: Remedial
Action, Treatment, and Disposal of Hazardous Waste, April
10-12, 19S9, in Cincinnati, Ohio
9) Dobbs, Richard A., Fate-In-Treatment Data Bases, Fate In
Anaerobic Digesters, Briefing Presented to the Science
Advisory Board, June 22-23, 1S8S, 11 pages
10) Dobbs, Richard A., Protocol for Determination of Partition
Coefficients for Toxic Metals and Organics on Wastewater
Solids, October, 1987
11) Dobbs, Richard A., Treatability Testing Procedures and Data
for Sorption and Volatilization in Conventional Wastewater
Treatment, Briefing Presented to the Science Advisory Board,
June 22-23, 1989, 3d pages
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12) Fava, J-A. et al, Generalized Methodology for Conducting
Industrial Toxicity Reduction Evaluations (TREs), EPA/60Q/2-
88-070, April 1989
13) Grady, C.P. Leslie et al, Biodegradation Kinetics for Selected
Toxic/Hazardous organic Compounds, Presented at the AWMA/EPA
International symposium on Hazardous Waste Treatment:
Biosystems for pollution Control, February 20-23, 1959, in
Cincinnati, OH
14) Grady, c.P.L., Jr. et al, Determination of Biodegradation
Kinetics Through Use of Electrolytic Respirometry, Wat. Sci.
Tech. (Brighton), 21:957, 1989
15) Govind, Rakesh, S. Desai and H.H. Tabak, Determination of Monad
Kinetics of RCRA Compounds Using Respirametry for
Strueture^Biodegradation Relations, Presented at the ACS, I&EC
Division Spring Symposium on Emerging Technologies for
Hazardous Waste Treatment, May 1-4, 1989, Atlanta, GA
[Subsequently published by the ACS? Editors are D, William
Tedder and Frederick G. Pohland, in Emerging Technologies for
Hazardous Waste Management, 422 ACS Series, Washington, D.c.
(ISBN 0-8412-1747-S), 1990}
16) Govind, Rakesh, et al, Models for Fate and Removal of Toxic
Organics from Wastewater Systems, July 25, 1988
17) Govind, Rakesh, S. Desai and H.H, Tabak, Prediction and
Modeling of Biodegradation Kinetics of Hazardous Waste
Constituents, Presented at the 15th Annual Research symposium:
Remedial Action, Treatment and Disposal of Hazardous Waste,
April 10-12, 1989, in Cincinnati, OH
18) Grady, C.P. Leslie, Jr., Determination of Biodegradation
Kinetics Through Electrolytic Respirometry, Presentation for
the U.S. EPA, Science Advisory Board Review of the Toxics
Treatability and Toxicity Reduction Program, Risk Reduction
Engineering Laboratory, Cincinnati, OH, June 22, 1989, 29
pages
19) Grady, C.P* Leslie, Jr., Toxicity of 33 RCRA Compounds to
Activated Sludge Microorganisms, Presentation for the U.S.
EPA, Science Advisory Board Review of the Toxics Treatability
and Toxicity Reduction Program, Risk Reduction Engineering
Laboratory, Cincinnati, OH, June 22, 1989, 17 pages
20) Hannah, Sidney A, et al, Comparative Removal of Toxic
Pollutants by Six Wastewater Treatment Processes, JWPCF, 58:27,
January 1986
21) Hannah, Sidney A., Barry M. Austern, Atal E. Eralp and Richard
A. Dobbs, JWPCF, 60:1281, July 1988
21
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22) JWPCF, 60; 1850, Toxicity of Selected RCRA Compounds to
Activated Sludge Microorganisms, October 1988
23) Lai, L., C, Gao and R. Govind, Development of A Fate Model for
organic Pollutants in A Wastewater Treatment Plant, Department
of Chemical Engineering, University of Cincinnati, Cincinnati,
OH, Presented to the Science Advisory Board, June 22-23, 1989,
54 pages
24) Meier, John R. and Dolloff F. Bishop, Evaluation of
Conventional Treatment Processes for Removal of Mutagenic
Activity from Municipal Wastewaters, JWPCF, 57*999, October
1985
25) Meier, John R, et al, Genotoxic Properties of Municipal
Wastewaters in Ohio, Arch. Environ. Contam. Toxicol., 16:671,
1987
26) Mount, Donald I. and Linda Anderson-Carnahan, Methods for
Aquatic Toxieity Identification Evaluations: Phase I. Toxieity
Characterization Procedures, SPA/600/3-88/034, September 1988
27) Mount, Donald I, and Linda Anderson-Carnahan, Methods for
Aquatic Toxicity Identification Evaluations: Phase II. Toxicity
Identification Procedures, EPA/60Q/3-88/Q35, April 1989
28) Mount, Donald I. Methods for Aquatic Toxicity Identification
Evaluations: Phase III. Toxicity Confirmation Procedures,
EPA/600/3-88/036, February 198§
29) Noll, Kenneth E. and F* Thomas, DePaul and Associates, Emission
of Volatile Organic Compounds from Sewage Treatment Facilities
of the Metropolitan Sanitary District of Greater Chicago,
Volume l (Sponsored by the Metropolitan Sanitary District of
Greater Chicago), November 24, 1987
30) ORD Briefing Entitled Case Study, Toxicity seduction
Evaluation at the Patapsco Waste Water Treatment Plant,
Baltimore, Maryland
31) Sorption of Organics on Wastewater Solidss correlation with
Fundamental Properties, December 7, l§87
32) Tabak, Henry H., sanjay Desai and Rakesh. Govind,
Biodegradability Studies to support Model Development, Briefing
for the Science Advisory Board, June 22-23, 198§,
5 pages
34) TabaJc, Henry H., Sanjay Desai and Rakesh Govind, Determination
of Biodegradation Kinetics of RCRA Compounds Using Respirometry
for Structure-Activity Relationships, Presented at the 44th
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Annual Purdue industrial Waste Conference, May 9-11, 1989, in
West Lafayette, IN
35) USEPA, Effluent Guidelines Division (WH-552), Fate of Priority
Pollutants in Publicly Owned Treatment Works, EPA 440/1-82/303
(Several Volumes), September 1982
36) Tabak, Henry H. Sanjay pesai and Rakesh Govind, The
Determination of Biodegradability and Biodegradation Kinetics
of organic Pollutant Compounds with the Use of Electrolytic
Respiroraetry, Presented at the 15th Annual Research symposium:
Remedial Action, Treatment and Disposal of Hazardous Waste,
April 10-12, 1989, in Cincinnati, OH
46) USEPA, Proposed Pollution Prevention Policy statement, Federal
Register. Vol. 54, No. 16, January 26, 1989, pp. 3845-3847
37) USEPA, Science Advisory Board, Future Risk; Research Strategies
for the 1990's, SAB-BC-88-040, September 1988
38) USEPA, science Advisory Board, APPENDIX E: Strategies for Risk
Reduction Research, SAB-EC-88-Q40E, September 1988
39) USEPA, Science Advisory Board, Report of the Environmental
Engineering Committee on Resolution on the Use of Mathematical
Models by EPA for Regulatory Assessment and Decision-Making,
EPA-SAB-EEC-89-012, January 1989
40) USEPA, Science Advisory Board, Report of the Pollution
Prevention Subcommittee on Review of the ORD Draft Pollution
Prevention Research Plan: Report to Congress, EPA-SA1-EEC-89-
037, September 1989
41) USEPA, Toxicity Reduction Evaluation Protocol for Municipal
Nastewater Treatment Plants, EPA/600/2-88/062
42) Young, James C* and Henry H» Tabak, Assessing Toxicity of
Organic Chemicals to Anaerobic Treatment Processes, Presented
at the 1989 TAPPI Environmental Conference, April 17-19, 1989,
in Orlando, FL
43) Young, James C., Protocol for Determining the Transformation
and Impact of Toxic Chemicals in Anaerobic Processes,
Presentation Notes for Science Advisory Board Review of the
Toxics TreataMlity and Toxicity Reduction Program, June 22,
1989, 39 pages
44) Young, James C. and Henry H. Tabak, Screening Protocol for
Assessing Toxicity of Organic Chemicals to Anaerobic Treatment
Processes, Presented at the &1MA/EPA International Symposium
on Hazardous Waste Treatment: Biosystems for Pollution Control,
Cincinnati, Ohio, February 20-23, 1989
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