vvEPA
United States
Environmental Protection
Agency
Research and Development (481)
Solid Waste and
Emergency Response (5102G)
EPA542-F-97-012b
November 1997
Bioremediation of Chlorinated
Solvents Consortium
RTDF
Remediation Technologies
Development Forum
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What Is the Bioremediation
Consortium?
The Bioremediation of Chlorinated Solvents Consortium is one of seven
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 devel-
oping innovative solutions , to mutual hazardous waste problems. The
Bioremediation Consortium was established in May 1993, when representa-
tives from various companies, universities, the EPA, the Department of
Defense (DOD), and the Department of Energy (DOE) met to discuss their
shared interest in developing 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
agreement 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 companies,
Beak International and ICI Americas, joined the Bioremediation Consortium
in Spring 1996.
What Is the Problem of Concern?
Chlorinated solvents are the rriost common contaminants resulting from indus-
trial and government operations. Used as solvents and degreasers, they are typi-
cally found in the soils and ground water adjacent to manufacturing, mainte-
nance, and service installations around the world. Although complete degrada-
tion of chlorinated solvents to harmless end products is known to occur, a better
understanding of how to predict and manage these degradation processes is
needed to ensure their use as cost-effective, practical solutions.
What Is the Mission of the
Bioremediation Consortium?
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. To accomplish this mission, the Consortium
members jointly participate 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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Comctabolic Bioventing
Soli Gas
Monitor
Low Rate Air and
Cometabolite Injection
Ground Water
Monitoring Well
Soil Gas
Monitor
What Processes Will Be
Studied?
The Consortium focuses on three in situ bioremediation
processes: cornetabolic 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 also involve less cost than conventional
pumping and treating. The Bioremediation Consortium initi-
ated 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 n field studies for
each of the processes at another site.
Conietabolie Bioventing. Laboratory studies have shown
that aerobic degradation of trichloroethene (TCE) in soils
occurs most easily in the presence of a cometabolite, such
as toluene, propane, or methane. Cornetabolic 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 objec-
tive of the RTDF cornetabolic bioventing study is to develop
a cost-effective process that promotes the cornetabolic
bioremediation of TCE and other chlorinated solvents. The
Consortium initiated the Phase I Cornetabolic Bioventing
Study- at Dover AFB, where TCE is present in sandy soil.
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 chlorinated
methanes, ethanes, and aromatica by reductive dehalogena-
tion or by oxidation. 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
natural attenuation occurs. Data from both field and labora-
tory studies will be used to develop a predictive natural
attenuation model that will relate the measured degradation
rates to the expected time course and outcome of intrinsic
bioremediation. The Consortium initiated the Phase I
Intrinsic Bioremediation Study at Dover AFB, where
chloroethenes 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.
Accelerated Anaerobic Biodegradation. The rate of
in situ anaerobic dechlorination is typically limited by the
availability of food and nutrients for microbial growth. The
purpose of the accelerated anaerobic degradation study is to
discover what these nutritional limitations are and how to
effectively deliver nutritional additions to the aquifer in
order to facilitate the use of this technology at other sites.
Other study objectives include determining which electron
donors and acceptors best support anaerobic bioremediation;
optimizing the chlorocarbon destruction rate; determining
what factors control the degradation kinetics; and gathering
cost and performance data. The Bioremediation Consortium
has begun a Phase I field study to test the accelerated anaer-
obic process at Dover AFB.
What Are the Consortium
Members' Roles?
Every Consortium member plays a specific role in the collab-
orative 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 effective-
ness of the technologies.
The companies are sharing proprietary information, patented
technologies, and their collective understanding and experi-
ence in bioremediation mechanisms and kinetics, hydroge-
ology, and nutrient delivery systems to support the develop-
ment 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 developing bioventing processes to support the
laboratory and field testing efforts for the cornetabolic
bioventing study. The Air Force brings its expertise in biore-
mediation and bioventing, as well as support for site charac-
terization and field work at Dover AFB. DOE is applying its
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substantial bioremediation expertise and laboratory experi-
ence, as well as tools for microbial characterization that will
be useful in these studies.
What Activities Have Been
Completed?
Cometabolic Bioventing. Using Dover AFB soil, intensive
testing with microcosms revealed that cosubstrates propane
and toluene stimulated TCE biodegradation at relatively fast
rates. Soil column tests, established to simulate in situ air
injection, confirmed the microcosm tests. Propane was
chosen to be used as the cosubstrate for the field pilot test.
The column tests also showed that propane stimulated
Intrinsic Bioremediation and
Accelerated Anaerobic Biodegradation
Ground Water F ow
cometabolic biodegradation of a co-contaminant at Dover
AFB, trichloroethane (TCA). A pilot-scale field system was
designed and installed at the Bldg. 719 site at Dover AFB, a
jet engine maintenance facility with associated TCE- and
TCA-contaminated soil. The pilot system is scheduled to
begin operation in October 1997. A mathematical model is
being developed to simulate cometabolic bioventing. It will
be tested against the monitoring data generated in the field
test.
Accelerated Anaerobic Biodegradation. As part of pilot
start-up procedures, a tracer test was performed to monitor
hydrologic performance within the test cell. Data from this
test were used to calibrate the flow and transport model
developed during the pilot design. Based on tracer test and
operating data from the first year of operation, the pilot is
performing as designed in terms of nutrient delivery and
water movement. PCE and TCE have been degraded to levels
below detection limits in approximately half of the pilot cell.
Significant degradation of these compounds has occurred
over the rest of the pilot area. Cis-DCE levels have increased
with no apparent degradation of this daughter product to date.
As a result of this development, the Consortium elected to
augment a portion of the pilot with microorganisms that have
the ability to further degrade DCE and vinyl chloride. The
Consortium is hopeful that the augmenting organisms will
complete the degradation process after sufficient residence
time has elapsed. Operation and evaluation of the pilot is
scheduled to continue until February 1998.
Intrinsic Bioremediation. A modular computer model for
simulating natural attenuation in ground water has been
developed. The Consortium intends to use data collected as
part of the intrinsic pilot in the application of the model to the
Dover AFB site. The model will be in the public domain and
can be used on personal computers. A detailed analysis of
ground-water data from site-monitoring wells was used to
calculate the apparent flux of chlorinated compounds across
the plume. Results are being compared with similar calcula-
tions made using ground-water data collected as part of an
elaborate "transect" study involving over 100 discrete
ground-water samples. The samples were collected along
three "transects" of the plume using direct-push sampling
techniques. In addition to sample collection, individual
measurements of hydraulic conductivity were made at each
location. The Consortium will evaluate these two methods of
flux calculation within the next program year. The intrinsic
bioremediation study is scheduled to run through 1998 at
Dover AFB.
What Activities Are Planned?
Research efforts on the three Phase I projects will continue
until 1998. Hill AFB has been chosen for Phase II
Cometabolic Bioventing work. Currently, lab work using site
soil is underway. The Consortium continues to search for
sites for Phase II Intrinsic Bioremediation and Accelerated
Anaerobic Biodegradation work.
What Are the 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, which allows government agencies
to work with industry on collaborative research efforts. DOE
has contributed significant funding for the intrinsic bioreme-
diation 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.
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Who Are the Consortium Members?
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Beak International
Ciba-Gcigy Corporation
Dow Chemical Company
DuPont
General Electric
IC1 Americas
Novartis
Zcneca, Inc.
n
U.S. Air Force
U.S. Department of Energy
U.S. Environmental
Protection Agency
The Bioremediation Consortium
Steering Committee
Beak International
Dave Major
519-763-2325
dmajor@beak.com
Novartis
John Licala
910-632-2372
john.Iicala@ep.novartis.com
Dow Chemical
Gary M. Klecka
517-636-3227
usdowq8x@ibmmail.com
DuPont
David E, Ellis
Steering Committee Chairperson
302-H92-744S
ellisde@csoc.dnct.dupont.com
General Electric
Joseph Salvo
518-387-6123
salvo@crd,ge.com
ICI Americas
Martin Bell
011-44-1928-517-875
martin.bell@ukrnh72.c+p.ici.tmailuk.spr
int.com
Zeneca
Malcolm Watts
302-886-3085
U.S. Air Force
Catherine Vogel
904-283-6208
cathy_vogel@ccmail.aleq. tyndall.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@epamail.epa.gov
RTDF
Remediation Technologies
Development Forum
Would You Like
More Information?
For more information on the Bioremediation
Consortium, please contact:
David E. Ellis, Ph.D.
DuPont Specialty Chemicals
Barley Mill Plaza 27
P.O. Box 80027 - Routes 141 & 48
Wilmington, DE 19880
Tel: 302-892-7445
E-Mail: ellisde@csoc.dnet.dupont.com
Gregory D. Sayles, Ph.D.
U.S. Environmental Protection Agency
National Risk Management Research
Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
Tel: 513-569-7607
E-Mail: sayles.gregory@epamail.epa.gov
For information on the RTDF or other
Action Teams, please visit the RTDF World
Wide Web site at www.rtdf.org or contact:
Robert Olexsey
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, OH 45268
Tel: 513-569-7861
E-mail: olexsey.bob @ epamail.epa.gov
Walter W. Kovalick, Jr., Ph.D.
U.S. Environmental Protection Agency
401M Street, SW (5102G)
Washington, DC 20460
Tel: 703-603-9910
E-mail: kovalick.walter@epamail.epa.gov
To request other RTDF fact sheets, please
write/fax to:
EPA/NCEPI
11305 Reed Hartman Highway, Suite 219
Cincinnati, OH 45241
Fax: 513-489-8695
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