United States
Environmental Protection
Agency
Research and Development (481)
Solid Waste and
Emergency Response (5102G)
EPA/542/F-99/024
November 1999
vvEPA
of Chlorinated
Solvents Consortium
RTDF
Current RTDF
ActibiHGTeams
Bioremrdiatiim Consortium
HNERT Soil-Metals Action
Permeable Reactive
BarrieVs Action Team
Orgames Action Team
Sediments Remediation
The Bioremediation of Chlorinated Solvents Consortium is one of the five
current Action Teams of the Remediation Technologies Development
Forum (RTDF). The RTDF was created in 1992 by the U.S.
Environmental Protection Agency (EPA) to foster collaboration between
the public and private sectors in developing innovative solutions to
mutual hazardous waste problems. The Bioremediation Consortium was
established in May 1993, when representatives from various companies,
universities, the EPA, the Department of Defense (DOD), and the
Department of Energy (DOE) met to discuss their shared interest in devel-
oping in situ bioremediation technologies to degrade chlorinated solvents
in soils and ground water. As a result of that first meeting, the industrial
partners of the Bioremediation Consortium—DuPont, Dow, General
Electric, Monsanto, Zeneca, and Ciba-Geigy—-signed a research agree-
ment in September 1994. Agreements then were negotiated with EPA,
the Air Force, and DOE to facilitate collaboration between the public and
private sectors on the planned research projects. Two additional compa-
nies, Beak International and ICI Americas, joined the Bioremediation
Consortium in Spring 1996. Recent changes to the Bioremediation
Consortium include the withdrawal of Monsanto and the addition of
GeoSyntec Consultants, replacing Beak International.
The Problem of Concern
Chlorinated solvents are common contaminants resulting from industrial
and government operations. Used as solvents and degreasers, they are
typically found in the soils and ground water near manufacturing, mainte-
nance, and service installations around the world. Biodegradation of
chlorinated solvents occurs naturally to varying degrees at many sites.
A better understanding of how to predict and manage these degradation
processes is needed to ensure their use as cost-effective, practical solu-
tions.
The Consortium's Mission
The mission of the RTDF Bioremediation Consortium is to accelerate the
development of the most cost-effective in situ bioremediation processes
for degrading chlorinated solvents. Consortium members jointly partici-
pate in the research, development, demonstration, and evaluation efforts
necessary to achieve public and regulatory acceptance of these biological
processes. In addition, the data generated and experience gained by the
Consortium in conducting field studies with these processes will be used
to develop guidelines for their use at other contaminated sites.
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Accelerated Anaerobic Biodegradation
"SST
Processes Under study
The Consortium focuses on three in situ bioremedia-
tion processes: cometabolic bioventing (for treatment
in the vadose zone), intrinsic bioremediation (for
treatment of the bulk of a plume), and accelerated
anaerobic biodegradation (for treatment of more
concentrated areas of a plume). These technologies
are environmentally friendly, they cause minimal
disturbance to the site as they require few surface
structures. They can be less costly than conventional
pumping and treating. The Consortium initiated
Phase I field tests of the three processes at Dover Air
Force Base (AFB) in Dover, Delaware, in early
1995. Planning is underway to conduct Phase II
field studies for each of the processes.
Cometabolic Bioventing
Laboratory studies have shown that aerobic degrada-
tion of trichloroethylene (TCE) in soils occurs only
in the presence of a cometabolite, such as toluene,
propane, or methane. Cometabolic bioventing uses a
technique, similar to methods currently used in
bioventing technology, to efficiently deliver oxygen
and a cometabolite to the vadose zone in order to
remediate TCE. This technology appears to have
great promise. The objective of the RTDF cometa-
bolic bioventing study is to develop a cost-effective
process that promotes the cometabolic bioremedia-
tion of TCE and other chlorinated solvents.
Intrinsic Bioremediation
Intrinsic bioremediation, or natural attenuation, of
chlorinated solvents in ground water can occur at
sites where indigenous microbial populations are
present that can degrade these chemicals. Certain
microorganisms are capable of detoxifying chlori-
nated methanes, ethanes, ethylenes, and many other
compounds by reductive dehalogenation or by oxida-
tion. These processes can result in complete
biodegradation to innocuous end products. The
objective of the natural attenuation research effort is
to quantitatively determine where, at what rate, and
under what conditions intrinsic bioremediation
occurs.
Accelerated Anaerobic Biodegradation
Complete in situ anaerobic dechlorination requires
that the necessary microorganisms are present. The
dechlorination is typically limited by the availability
of food and nutrients for microbial growth. The
purpose of the accelerated anaerobic degradation
study is to (1) understand the microorganisms
involved, (2) identify the nutritional requirements,
(3) determine how to effectively deliver the nutri-
ents, and (4) determine how to effectively deliver
microorganisms to the aquifer, when needed. Other
study objectives include determining which electron
donors and acceptors best support anaerobic biore-
mediation; optimizing the chlorocarbon destruction
rate; determining what factors control the degrada-
tion kinetics; and gathering cost and performance
data in order to facilitate the use of this technology
at other sites.
Consortium Members' Roles
Every Consortium member plays a specific role in
the collaborative efforts for the three bioremediation
processes. Each organization brings particular
knowledge and expertise, as well as laboratory
research, field studies, and resources necessary to
conduct the projects and evaluate the effectiveness
of the technologies.
The companies are sharing proprietary information,
patented technologies, and their collective under-
standing and experience in bioremediation mecha-
nisms and kinetics, hydrogeology, and nutrient
delivery systems to support the development and
testing of the three bioremediation processes.
EPA's National Risk Management Research
Laboratory (NRMRL) in Cincinnati, Ohio, is
applying its knowledge and experience in devel-
oping bioventing processes to support the laboratory
and field testing efforts for the cometabolic
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Consortium Members
The Bioremediation Consortium
Steering Committee
GeoSyntec Consultants
David Major
519-822-223
dmajor@geosyntec.com
Ciba Specialty Chemicals
Dan Pardieck
732-914-2894
dan.pardieck@cibasc.com
Dow Chemical Company
Gary M. Klecka
517-636-3227
gmklecka@dow.com
DuPont
David E. Ellis
Steering Committee Chair
302-892-7445
david.e.ellis@usa.dupont.com
General Electric
Richard Sheldon
518-387-6565
sheldon @ crd.ge.com
ICI Americas
Martin Bell
011-44-1606-704-401
martin_bell @ ici.com
Zeneca
Malcolm Watts
302-886-3085
U.S. Air Force Research Laboratory
Tim Wiley
850-283-6299
tim.wiley@mlq.afrl.af.mil
U.S. Department of Energy
Skip Chamberlain
301-903-7248
grover.chamberlain@em.doe.gov
U.S. EPA/National Risk Management
Research Laboratory
Gregory D. Sayles
513-569-7607
sayles .gregory @ epa.gov
Industry
Ciba Specialty Chemicals
Dow Chemical Company
DuPont
General Electric
Government
GeoSyntec Consultants
ICI Americas
Zeneca
U.S. Air Force
U.S. Department of Energy
U.S. Environmental Protection Agency
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country during 1999. Both the manual and informa-
tion on course offerings are available on the Internet
at www.biotreat.state.pa.us.
Accelerated Anaerobic Biodegradation. The
Consortium conducted a proof of technology pilot
test at Dover AFB from September 1996 to March
1998. The system (shown below left) included three
extraction wells and three injection wells, each
screened to a depth of 38-48 ft bgs. These wells
formed a rectangular, hydraulically-controlled cell
that was 40 ft. wide and 60 ft. long. The pilot
system was designed to operate as a "closed loop"
recirculation cell, providing a residence time of
about 60 days. Sodium lactate, ammonia, and phos-
phate were injected into extracted ground water.
During the first five months of operation, the
concentration of TCE gradually decreased, cis-
dichloroethylene (cis-DCE) showed a slight increase,
and there was no increase for vinyl chloride or
ethylene, indicating that limited dechlorination was
occurring. After increasing the substrate feed
concentration to 200 mg/L, an increase was noted in
DCE concentrations, along with a decrease in TCE
concentrations, however, there was no evidence that
dechlorination beyond DCE was occurring. In June
1997, 351 liters of an aqueous culture from a DOE
site in Largo Florida was injected into the recircula-
tion cell (bioaugmentation). By September 1997,
vinyl chloride and ethylene began appearing in
wells closest to the injection wells. By March 1998,
all TCE and DCE in the ground water were
converted to ethylene, and between 75% and 80% of
the TCE and DCE had been recovered as ethylene.
The Consortium is analyzing final results of the
pilot test and testing parameters involved with tech-
nology scale up.
The Consortium's Plans
Research efforts on the three Phase I projects will
continue through 1999. Performance data from the
Phase I cometabolic bioventing study are being
compiled and are expected to be available late in
1999. The Phase II work at Hill AFB began in
summer 1999. In addition, a mathematical model is
being developed to simulate cometabolic bioventing
and will be tested against the monitoring data gener-
ated in the field test.
The Consortium has selected a site in Niagara Falls,
New York, for research into the natural attenuation
of source areas for the Phase II intrinsic bioremedia-
tion work. The Consortium also is examining the
importance of natural attenuation at Kelly Air Force
Base, Texas, as part of its Phase II work. In addi-
tion, the Consortium is involved, through the U.S.
Department of Defense Environmental Security
Technologies Certification Program (ESTCP) in
demonstrating bioaugmentation at Fallen Naval Air
Station (NAS), Nevada.
Consortium members are working with the
Interstate Technology Regulatory Cooperation
(ITRC) Work Group to develop training on acceler-
ated anaerobic biodegradation of chlorinated
solvents. Pilot offerings of the training are expected
to begin late in 1999.
Consortium Funding Sources
EPA provides the necessary funds and staff to
support and facilitate Bioremediation Consortium
meetings. Staffing, funding, and equipment needed
to develop and test these three bioremediation
processes are being provided by the Bioremediation
Consortium members. Both EPA and the Air Force
work through a Cooperative Research and
Development Agreement (CRADA), which allows
government agencies to work with industry on
collaborative research efforts. DOE has contributed
significant funding for the intrinsic bioremediation
and accelerated anaerobic biodegradation Phase I
projects. The Phase I cometabolic bioventing field
study has been primarily funded by the EPA, the Air
Force, and Zeneca. Additional funding for Phase II
intrinsic bioremediation and cometabolic bioventing
projects has been provided by the Chlorine
Chemistry Council.
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bioventing study. NRMRL also provides technical
assistance to the ground-water projects. The Air
Force brings its expertise in bioremediation and
bioventing, as well as support for site characteriza-
tion and field work at Dover AFB. DOE is applying
its substantial bioremediation expertise and labora-
tory experience, as well as tools for microbial char-
acterization that will be useful in these studies.
Accomplishments
Cometabolic Bioventing. The Consortium
conducted a Phase I cometabolic bioventing study at
the Bldg. 719 site at Dover AFB, Delaware, a jet
engine maintenance facility with TCE- and
Cometabolic Bioventing
Low Rate Air and
CometeboNte Injection
Soil Gas , Ground Water
Monitor Monitoring Weli
SoiiGas
Monitor
trichloroethane (TCA)-contaminated soil. Prior to the
Phase I field demonstration, microcosm and column
tests were performed using soil from the Dover AFB
site to identify substrates. The results of these tests
indicated that co-substrates propane and toluene
stimulated TCE biodegradation at relatively fast rates
and that propane stimulated cometabolic biodegrada-
tion of TCA. Propane was chosen to be used as the
co-substrate for the field pilot test. The Consortium
designed, installed, and began operating the pilot-
scale field system in May 1998. The system
consisted of a test plot approximately 30 ft long, 20
ft wide, and 10 ft deep, with three injection wells
screened to a depth of 10 ft below ground surface
(bgs). An air sparge blower was used to inject a
mixture of air and propane (300 ppm in air) at a rate
of 1 ft3/minute. The Phase I study will be completed
late in 1999.
The Consortium has chosen Operable Unit 2, Hill
Air Force Base (AFB) in Utah for Phase II cometa-
bolic bioventing work. Laboratory microcosm and
soil column tests, conducted using site soils, showed
that TCE and TCA could be biodegraded best in the
presence of cosubstrate propane. Preliminary field
design data was collected at the site in early 1999.
Intrinsic Bioremediation. The Consortium
conducted a four-year Phase I intrinsic bioremedia-
tion study at the Area 6 site at Dover AFB,
Delaware, where chloroethylenes are present in
shallow ground water. Key to selection of Dover
AFB as the test site was the presence of an active
microbial population, which was evidenced by the
detection of degradation products at the site. Results
of the study indicate that contaminant concentrations
have decreased markedly over the test period. The
Consortium published a report in 1999 related to the
the Phase 1 natural attenuation work. "Groundwater
Geochemistry of Area 6, Dover Air Force Base,
Dover, Delaware." The report is available from the
National Technical Information Service (NTIS). The
Order Number is PB99-162430/XAB.
The Consortium also conducted a detailed analysis
of ground-water data from site-monitoring wells to
calculate the apparent flux of chlorinated compounds
across the plume. Results of this analysis are being
compared with similar calculations made using
ground-water data collected as part of an elaborate
"transect" study involving over 100 discrete ground-
water samples, and Consortium members are evalu-
ating these two methods of flux calculation.
In addition, the Consortium used data from both
field and laboratory studies to develop a predictive
natural attenuation model that relates the measured
degradation rates to the expected time course and
outcome of intrinsic bioremediation. The model is in
the public domain and can be used on personal
computers.
Industrial members of the Consortium, in coopera-
tion with the Western Governors Association and the
Interstate Technology Regulatory Cooperation
(ITRC) Work Group, have published the Natural
Attenuation of Chlorinated Solvents Principles and
Practices Manual. With ITRC sponsorship, the
Consortium's industrial members also developed a
two-day "Natural Attenuation of Chlorinated
Solvents in Ground Water" training course. The
course was delivered at several locations around the
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RTDF
Remediation Teohjioiugiss
Fortraj
Would You Like
More Information?
For more information on the Bioremediation
Action Team, please contact:
David E. Ellis, Ph.D.
DuPont Engineering
Barley Mfllltea 37-2234
P.O. Box $0*27 - K0nt*$ 144 & 48
Wilmington, DE 19880
(302) 892-7445
E-Mail: david.e.ellis@usa.duppnt.com
Greg Sayles, Ph.D.
tJ(S. EPA/NRMRL
26 W. Martin Luther King Dr.
Cincinnati, OH 4526$
(513)569-7607 , /
E-Mail: sayles.gregory@*jjij*.g»v
For information on the RTDF W Other
Action Teams, please visit the KIW World
Wide Web site at www.rtdf.org of contact:
Robert Olexsey
U.S. Environmental Protection Agency
26 West Martin Luther JCmg Drive
Cincinnati, OH 45268
Tel: 513-569-7861
E-mail: olexsey.bob @«pamail.epa.gov
Walter W. Kovalich, Jr., Ph.D.
U.S. Environmental Protection Agency
401 M Street, SW (5102G)
Washington, DC 20460
Tel: 703-6J3-9910
E-mail: kovalick.waltir@epamail.epa.gov
To request other RTDF fact sheets, please
write/call
EPA/N$£EP
P.O. Sox 42419
Cincinnati, OH 45242
Phone: 800-490-9198
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