SUMMARY REPORT
HIGH-PRIORSTY O^ B8OR1MEDIATION
BIOREMEDIAT1ON RESEARCH
NEEDS WORKSHOP
April 15-16,1991
Washington, DC
v/EPA
U.S. Environmental Protection Agency
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EXECUTIVE SUMMARY
At the request of the EPA Bio re mediation Action Committee, a workshop was held on April
15 and 16, 1991 to propose high priority topics for research to further advance bioremediation
technologies. Forty-five scientists, engineers, and research administrators from governmental
agencies, industry, and academia participated. The participants proposed four major areas for
research:
I. Determining factors governing the availability of pollutants for bioremediation and
devising ways to increase their availability for destruction.
2. Improving the design of processes for bioremediation.
3. Overcoming problems associated with scale-up from simple laboratory systems to field
operations.
4. Developing innovative and novel bioremediation processes.
The results of the research should greatly expand the utility and scope of use of
bioremediation for the clean-up of contaminated waters, soils, and aquifers.
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HIGH-PRIORITY RESEARCH CH BIOREMEDIATION
REPORT OF WORKSHOP
April 15-16, 1991
I. INTRODUCTION
The Environmental Protection Agency (EPA) sponsored an EPA-Industry Meeting on the
Environmental Applications of Biotechnology on February 22, 1990. The purpose of the meeting
was to discuss ways to apply bioremediation technologies to solving problems arising from
environmental pollution with chemicals. As a result of that meeting, EPA formed a Bioremediation
Action Committee (BAC) and established six subcommittees of BAC to facilitate further development
of the technologies. Dr. John H. Skinner, Deputy Assistant Administrator of-EPA for Research and
Development, was named as BAC chair.
The BAC recommended that
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Many conferences and workshops have been held on bioremediation and biodegradation. The
participants in several of these meetings formulated recommendations for research needs. However,
the purposes of these meetings were rarely the establishment of the research needs of highest
priority, and recommendations emanating from those meetings, although important, do not address
solely the major limitations to the rapid introduction of new approaches to bioremediation.
Nevertheless, those lists of research needs often contain many of the recommendations presented
here. To facilitate the development of recommendations by the EPA-sponsored workshop and to
provide a clear focus to its deliberations, the organizers of the workshop provided the participants
with the recommendations from these previous conferences and, in addition, comments from several
individuals and groups.
II. CONTEXT OF THE RESEARCH PRIORITIES
A number of issues addressed at the workshop are appropriate as an introduction to the high-
priority research needs. These issues need to be stated explicitly to provide a meaningful context for
the ultimate use of the information obtained from the research that is recommended.
Both short- and long-term investigations are essential. Some of the major issues indicated
below will be resolved reasonably readily, and the information will quickly contribute to
bioremediation in the field. Answers to some of the other issues will take more time, but
information on those subjects is no less important. It would be imprudent to support only research
on topics that will provide a short-term payoff, because the other information gaps will still exist
at the completion of the short-term research: A prudent approach would involve providing adequate
financial support for research that is designed to bring some bioremediation technologies to practical
utility soon, as well as funding for research that will provide the information needed to develop
technologies for which the current state of information is inadequate. A balance should be
maintained between research for technologies that will be useful in the near future and those that
will solve the more difficult problems.
Implicit in our statement of research needs is the assumption that the identities and
concentrations of the products of bioremediation will be determined. This information is required
to serve as a basis for determining the transport, fate, and possible toxicity of the chemical products
generated as a result of bioremediation.
Research designed to establish better bioremediation technologies should be coupled with
economic analyses of these technologies and economic comparisons of bioremediation with other
means for ridding the environment of pollutants.
The information gained from the research proposed herein ultimately must be considered in
the context of specific sites of contamination. Thus, the appropriate bioremediation technology for
a given site may involve either in-situ approaches or above-ground bipreactors. The remediation
may be best carried out by an aerobic or anaerobic process, or a particular pollutant, mixture of
contaminants or site characteristics may dictate that an innovative process be developed.
The priorities for research apply to both organic and inorganic contaminants. Although
much of the put research on bioremediation has focused on organic materials, sites contaminated
with inorganic substances, including metallic ions, may also be remediated biologically by oxidizing
or reducing inorganic contaminants to nontoxic forms or by immobilizing or retaining these
pollutants in a fashion that the exposure of sensitive species is reduced or that the product can be
removed from the site.
Biological processes for remediation will often not work alone. They may need to be
combined with other treatment technologies to ensure effective or rapid treatment. The need for
several technologies to be used at a single site is particularly important for complex wastes.
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The research needs given below are not presented in terms of relative priorities, but represent
issues for which solutions are essential in order to have more effective and more widely used
biological approaches to remediation of contaminated sites.
III. HIGH-PRIORITY RESEARCH NEEDS
A. Bioavailability
Many compounds or pollutants that are quickly biodegraded under laboratory conditions
persist in the environment. Attempts to enhance the biological destruction of these compounds often
have limited success because they are not readily available for microbiai destruction in the forms
and physical or chemical states in which they exist at sites of contamination. Thus, although the
pollutants potentially may be destroyed by microbiological means, environmental factors and the
physical or chemical state of the substance prevent its rapid degradation in the field by presently
available procedures. This constraint on bioremediation represents a major limitation co the
widespread use of many biological technologies.
Sorption/Desorption. Research should be conducted to determine the role of sorption and
desorption in governing the susceptibility of chemicals at contaminated sites to
bioremediation. Methods should be sought to enhance the destruction of compounds or
materials whose availabilities are limited because of their sorption to environmental
surfaces or their slow desorption to forms available for microbiai degradation.
Non-Aqueous Phase Liquids. Studies are needed to determine the role of non-aqueous
phase liquids in determining the resistance or slow degradation of compounds that
otherwise would be rapidly destroyed. Many pollutants are present in non-aqueous
phase liquids in subsoils, aquifers, and surface waters, and compounds in these non-
aqueous liquids may be protected from rapid destruction. Technologies need to be
developed to enhance the bioremediation of sites containing unwanted chemicals in non-
aqueous phase liquids.
Matrix Effects. Investigations are required to determine the role of the physical matrix
in which pollutants are found on their susceptibility to biological destruction. The role
of diffusion of a chemical from a physically inaccessible site and of tortuosity in polluted
sites should be clarified. Means to overcome problems associated with the physical matrix
of the waste should be defined.
Weathering/Aging. The availability of many chemicals for biological destruction
diminishes with time. The reasons for the diminished availability of the substances and
ways to bring about the biological destruction of the resulting weathered pollutants should
be investigated.
Immobilization and Solubilization. Microorganisms frequently bring about reactions that
result in immobilization, fixation, precipitation, or solubilization of organic or inorganic
compounds or ions. Such processes may detoxify substances that otherwise would be
harmful. Research is required to further define these processes and to devise practical
means to exploit them under field conditions.
Limits to Bioremediation. Research is needed to determine the physical and chemical
reasons why a biodegradable compound is sometimes not available for biodegradation.
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B. Process Design
Devising practical solutions to existing and future problems of environmental pollution will
require additional information on the design and evaluation of specific approaches for
bioremediation. A particular technology may appear to be feasible based upon small-scale laboratory
tests, but many of the proposed processes are presently not yet suitable for field use and require
further development and optimization.
Research on process design should focus on both in-situ bioremediation and above-ground
bioreactors, including bioremediation by land treatment and composting. Except as indicated, the
proposed research refers both to in-situ bioremediation and above-ground bioreactors.
Factors limiting the rates of biodegradation should be defined. Often, the rate of in-
situ bioremediation or treatment in above-ground reactors can be markedly increased,
but procedures for increasing the rates require information on the factors limiting those
rates.
Information is required oh-'the operation and on the durability and stability of
technologies for in-situ bioremediation and above-ground bioreactors.
Means should be developed for the more effective monitoring and control of
bioremediation processes and procedures.
New or better models should be-developed for bioremediation processes. These models
will permit the design of cost-effective, safe and practical technologies.
Research should be conducted to devise multi-stage processes--including
anaerobic/aerobic transformations, processes involving desorption followed by
biodegradation, and technologies involving chemical followed by biological treatment.
Investigations are needed on processes suitable for the destruction of chemicals present
at low concentrations. A process that is effective at high concentrations of a pollutant
may not be useful or may not be efficient when the pollutant of concern is at low levels.
Research is needed on the design of novel processes for bioremediation--including slurry
reactors, procedures involving vapor-phase treatment, technologies that enhance the rates
of cometabolism, etc.
Research on process design must be coupled with enhanced data collection, including
advanced technologies for data collection.
Information is required on the effect of environmental heterogeneity on in-situ
bioremediation.
Research should be conducted to determine the factors affecting the feasibility and the
extent of in-situ bioremediation.
Studies are required on factors determining the success of microbial inoculation of
contaminated sites and the mobility and survival of microorganisms added for in-situ
bioremediation.
A more extensive base of knowledge is required on mass transport--including delivery
systems for nutrients (N, P, etc.), electron acceptors (O2, H2O;, nitrate, and sulfate), and
electron donors (methane, methanol, etc.) and the mixing of solids, fluids, and chemicals.
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Further understanding is needed on factors limiting microbial populations and activities - -
including nutrient limitations, the toxicity of waste components to microorganisms, and
induction of biodegradative activity.
C. Scale-Up
A variety of problems become evident in attempts to conduct bioremediation in the field
based on simple laboratory evaluations of biodegradation. Research is needed on problems of scale-
up in order to permit effective remediation to be accomplished in the field. The heterogeneity of
sites in the field and scale-dependent transport and transformation processes often complicate facile
extrapolations from small operations in the laboratory to field programs. Issues of mass transport and
modeling are also particularly relevant to problems of scale-up, and are especially relevant to in-
situ bioremediation.
EPA together with other federal agencies should participate in the development and
funding of pilot-scale facilities to assure reproducible and rigorous research and to allow
for practical field-scale designs of bioremediation technologies
Consideration should be given to relaxing permitting requirements for research at such
facilities or to allowing access to existing hazardous waste sites.
Further research is required on microcosms as simulants of field conditions. The
availability of validated small-scale simulants would facilitate the development of new
technologies or better evaluations of which bioremediation technologies will be useful
under field conditions.
D. Innovative and Novel Processes
Although considerable progress has been made in devising procedures for biodegradation,
biotransformation, and bioremediation, major problems remain. Hence, an exploratory program is
essential in order that these less tractable problems might be resolved. Research on these processes,
in some cases, may be completed reasonably quickly, but frequently the needed investigations will
require long-term support, especially for the truly innovative approaches.
The bioremediation of many complex wastes will not be simple. Components of complex
wastes may be toxic and prevent bioremediation, or they may act antagonistically or synergistically
in ways that are now unpredictable.
Novel approaches are required for complex mixtures in order to remove or reduce the
toxicity to the organisms responsible for bioremediation or to devise multi-stage processes
including a phase of biological treatment.
Novel microbial processes should be sought--including cometabolic as well as anaerobic,
aerobic, and microaerophilic transformations. Compounds that are only cometabolized
represent a special category of concern because many of the current approaches to
bioremediation are not relevant to such chemicals. Research on novel microbial processes
should include investigations on the biochemical pathways and metabolic control of the
biodegradative transformation.
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IV. PARTICIPANTS IN WORKSHOP
Dr. Daniel A. Abramowicz
Manager, Environmental Technology
Program
Biological Sciences Laboratory
GE Corporate Research and Development
Dr. Martin Alexander
Professor
Department of Soil, Crop and
Atmospheric Sciences
Cornell University
Dr. Frederick Archibald
Pulp and Paper Research Institute of Canada
Dr. Ronald M. Atlas >''
Department, of Biology
University of Louisville
Dr. Steven D. Aust :
Biotechnology Center
Utah State University
Mr. Tom Baugh
Environmental Scientist
U.S. Environmental Protection Agency
Dr. Peter Chapman
U.S. Environmental Protection Agency
Ms. Sue Markland Day
Senior Research Associate
The University of Tennessee-Knoxville
Ms. Kate Devine
Applied Biotreatment Association
Dr. Pat Eagan
Director, Bioremediation Consortia
Biotechnology Center
University of Wisconsin
Mr. Robert D. Fox
IT Corporation
Dr. John Glaser
U.S. Environmental Protection Agency
Risk Reduction Engineering Lab
Dr. D. Jay Grimes
Ecological Research Division
Office of Energy Research
U.S. Department of Energy
Dr. Robert Hickey
Michigan Biotechnology Institute
Dr. Peter Holden
Australian Nuclear Science
and Technology Organization
Captain Kevin Keehan
U.S. Army Toxic and Hazardous Materials
Agency (USATHMA)
Mr. Richard Kibler
Directorate for Environmental Technology
Dr. Walter W. Kovalick, Jr.
Director
Technology Innovation Office
U.S. Environmental Protection Agency
Dr. Rashalee Levine
U.S. Department of Energy
Office of Technology Development
Dr. Richard G. Luthy
frofessor and Head
Department of Civil Engineering
Carnegie-Mellon University
Dr. Dale Manty
Office of Exploratory Research
U.S. Environmental Protection Agency
Dr. John McCarthy
Environmental Sciences Division
Oak Ridge National Laboratory
Dr. Perry McCarty
Director
Western Region Hazardous Substance
Research Center
Department of Civil Engineering
Stanford University
Dr. Beverly McFarland
Chevron Research and Technology
Corporation
Mr. Terry Mclntyre
Head, Biotechnology Section
Commercial Chemicals Branch
Conservation and Protection
Environment Canada
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Mr. James McNabb
U.S. Environmental Protection Agency
Robert S. Kerr Environmental
Research Laboratory
Dr. Laura Meagher
University Industry Liaison
Agricultural Biotechnology Center
Cook College, Rutgers University
Dr. Henryk Melcer
Wastewater Technology Centre
Environment Canada
Dr. Ronald H. Olsen
Professor of Microbiology
Department of Microbiology ' :t
University of Michigan Medical School
Dr. P.H. Pritchard
U.S. Environmental Protection Agency
Environmental Research Laboratory
Mr. Kevin Reilly
Acting Chief
Logistics and Operations Division
DL A-Defense National Stockpile Center
Dr. Rejean Samson
Section Head, Environmental Engineering
National Research Council Canada
Biotechnology Research Institute
Mr. Paul Schatzberg
Taylor Research Center
U.S. Department of the Navy
Mr. Alan Seech
Dearborn Chemical Co.
Wastewater Technology Centre
Dr. Jim C. Spain
U.S. Air Force Environmental Services
Center/RDVC
Dr. Hans Stroo
Remediation Technologies, Inc.
Dr. William A. Suk
National Institute of Environmental
Health Sciences
Dr. James Tiedje
Michigan State University
Center for Microbial Ecology
Dr. C. H. Ward
Professor and Chairman
Department of Environmental Science
and Engineering
Rice University
Dr. Walter J. Weber, Jr.
Director
Great Lakes and Mid-Atlantic Hazardous
Substance Research Center
Department of Civil Engineering
The College of Engineering
The University of Michigan
Ms. Beverly Whitehead
U.S. Department of Energy
Dr. John Wilson
U.S. Environmental Protection Agency
Robert S. Kerr Environmental Research
Laboratory
Dr. Richard E. Woodward
Vice President
ENSR Consulting and Engineering
Dr. R. Campbell Wyndham
Environmental Biology
Carleton University
Dr. Wally Zuk
Director of Environmental Science Programs
Australian Nuclear Science and Technology
Organization
Lucas Heights Research Laboratories
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