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 _ 'Permeable Reactive x *1 ^ •* Barriers[ActionTeam , ;'* IINERT Soil-Metals Action^ fTeani Sediments Remediation Action Team ~s -*, -i >-.,"' >i Iri: Situ Flushing Action 'f,: Team ""• , - - "T'\ , *', Phytoremediation of prganics Action Team , ; 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. ------- 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 ------- 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. ------- Who Are the Consortium Members? .L/ffl. 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 Copied on Recycled Paper ------- |