Application

Aerobic Non-Toxic Cometabolism of Trichloroethylene in Ground Water: A Case Study (Abstract)
Donofrio, Robert S. (BioRemedial Technologies, Inc.) Ronald M. Seech (MLT (ASCP). 12th Annual Technical Information Exchange (TIE) Workshop, 14-16 November 2000, Augusta, Georgia

BioRemedial Technologies, Inc., implemented a groundwater treatment system utilizing a non-toxic cometabolite, Compound C, for the aerobic removal of trichloroethylene in groundwater. The site was contaminated with PCE, TCE, cis-1,2-DCE, and VC. The approximate area of affected soil and groundwater was 50,000 square feet and included an extension of the contaminated plume downgradient from the source area. Average horizontal groundwater flow velocity was less than one foot per year. Site treatment began in October 1999. TCE concentrations in three of the four monitoring wells have been reduced by greater than 90% during the first two quarters of system operation. An overall cost savings in excess of $1,000,000 is estimated by the client when comparing the biological treatment system to other remediation technologies.

Bioenhanced In-Well Vapor Stripping (BEHIVS) to Treat Trichloroethylene
Strategic Environmental Research and Development Program (SERDP). 75 pp, 2003.

An in-well vapor stripper and two biotreatment wells were installed near a TCE-contaminated 'hot spot' zone at Edwards AFB for an August-December 2001 technology demonstration. In-well vapor stripping and in situ aerobic cometabolic bioremediation were combined to address a TCE source area without bringing contaminated ground water to the surface.

Case Histories from Eight Years of Successful Testing and Remediation Using Aerobic Soy Based Co-Metabolism for Removal of Chlorinated Hydrocarbons from Groundwater
D. Blackert and J. Cibrik.
The Business of Brownfields: 2009 Conference Proceedings, 15-17 April, Pittsburgh, PA. 8 pp, 2009

Aerobic cometabolism approaches—which combine air sparging, liquid/liquid extraction, and biological cometabolism—have been employed successfully at more than 10 field pilot- and full-scale implementations for remediation of halogenated hydrocarbons (TCE, carbon tetrachloride, chloroform) plus other hydrocarbons and fluorocarbons in groundwater, achieving 'no further action' approval at several sites. A soy methyl ester and a biodegradable surfactant blend has been used extensively for full-scale field application. The cases include a 2003 Kansas City pilot test to address TCE and DCE, followed by full-scale remediation in 2004.

Cometabolic Bioventing Field Test at Dover AFB (Abstract)
Sayles, G.D. (U.S. EPA, Cincinnati, OH); L.E. Moser (Zeneca Corp., Mississauga, Ont.); D.J. Gannon; P. Morgan (ICI Technology, Runcom, Cheshire, UK); T. Franz (Beatty and Franz and Assoc., Bolton, Ont.); A. Mason; S. Pfiffner (Univ. of Tennessee, Knoxville); A.V. Palumbo (Oak Ridge National Lab., Oak Ridge, TN); A. Lightner (Air Force Research Lab, Tyndall AFB, FL); S.P. Farrington (Applied Research Assoc., Inc., South Royalton, VT); J.A. Deramo (Dover AFB, Dover, DE); C. Mikula
Remediation of Chlorinated and Recalcitrant Compounds: The Second International Conference Battelle Press, Columbus, OH. 2000

A comprehensive field test of cometabolic bioventing was conducted at Dover Air Force Base, Dover, Delaware, by the Remediation Technologies Development Forum Bioremediation Consortium. The site was contaminated with TCE, 1,2-cis DCE and 1,1,1-TCA in the vadose zone. The strategy was to deliver a gaseous mixture of cosubstrate and air, as an oxygen source, to the vadose zone to drive the aerobic biodegradation of the target compounds. A 20 foot x 30 foot test plot was established that included air/propane injection and soil gas sampling points over a 10 foot depth interval below surface. A detailed performance monitoring program was implemented. Following a period of acclimation to propane, the system was operated from May 1998 to August 1999. Large drops over time of the VOC concentrations in the soil gas indicated that significant VOC removal was occurring, and the propane uptake tests showed that propane was rapidly used by the vadose zone microorganisms. Microbial analysis showed that the number of propane degraders increased during the test. The authors also discuss the results of initial and final soil sampling. Model simulations, from a mathematical model developed for process design and description, are presented and compared to the field data. Also see Cometabolic Bioventing at Building 719, Dover Air Force Base Cost and Performance Report (2000).

Cometabolic Degradation of TCE Vapors in a Foamed Emulsion Bioreactor
Kan, E. and M.A. Deshusses. Environmental Science and Technology, Vol 40, p 1022-1028, 2006

Effective cometabolic biodegradation of trichloroethylene (TCE) vapors in a novel gas-phase bioreactor called the foamed emulsion bioreactor (FEBR) was demonstrated. Toluene vapors were used as the primary growth substrate for Burkholderia cepacia G4 which cometabolically biodegraded TCE. Batch operation of the reactor with respect to the liquid feed showed a drastic decrease of TCE and toluene removal over time, consistent with a loss of metabolic activity caused by the exposure to TCE metabolites. Sustained TCE removal could be achieved when continuous feeding of mineral medium was implemented, which supported cell growth and compensated for the deactivation of cells. The TCE elimination capacity was 2-1000 times higher than reported in other gas-phase biotreatment reports. During the experiments, 85-101% of the degraded TCE chlorine was recovered as chloride. Overall, the results suggest that the FEBR can be a very effective system to treat TCE vapors cometabolically.

Evaluating the Efficacy of Bioaugmentation for In-Situ Treatment of PCB Impacted Sediments
Sowers, K.R., U. Ghosh, and H.D. May.
ESTCP Project ER-201215, 154 pp, 2018

Both anaerobic halorespiring and aerobic PCB-degrading bioamendments were mass cultured, transported to a site, and delivered through a water column to sediments without loss of viability. Treatment with the bioamendment mixture reduced the mean total PCB concentration by an average of 52% and the aqueous PCB fraction by 95% after 13.5 months. The innovative aspect of the technology is the application of activated carbon pellets as a solid substrate for 1) delivery of microorganisms into sediments and 2) sequestration and concentration of hydrophobic PCBs in close proximity to the PCB-transforming bacteria.

Field Evidence for Co-Metabolism of Trichloroethene Stimulated by Addition of Electron Donor to Groundwater
Conrad, M.E., E.L. Brodie, C.W. Radtke, M. Bill, M.E. Delwiche, M.H. Lee, D.L. Swift, and F.S. Colwell.
LBNL-3683E, 40 pp, 2010

Following favorable results from the 1999 pilot test, electron donor has been injected into the Snake River aquifer beneath the Test Area North site at Idaho National Laboratory for more than 10 years to stimulate microbial reductive dechlorination of TCE in groundwater. Significant TCE removal from the source area of the contaminant plume and elevated dissolved methane in the groundwater extending 250 m from the injection well are evident, indicating that electron donor amendment designed to stimulate reductive dechlorination of TCE can also stimulate cometabolism of TCE. [NOTE: this is the manuscript version of the paper in Environmental Science & Technology 44(12):4697-4704(2010)]

In-Situ Aerobic Bioremediation of Recalcitrant Organics: A Case Study Demonstrating Benefits and Potential Limitations
Brusenhan, J.D., M.F. Marcon, and M.T. Saul, CL-Solutions, LLC. A&WMA's 98th Annual Conference and Exhibition, 21-24 June 2005, Minneapolis, Minnesota, Paper 1069, 10 pp, 2005

A history of spills and/or releases at two adjacent dry cleaning facilities near Houston, TX, resulted in significant soil and shallow groundwater contamination with PCE and daughter products. Soil was relatively permeable, with rapid groundwater flow beneath the site. A long, narrow, off-site plume extended beneath a residential neighborhood. Chemical oxidation was employed initially with only limited success in the areas of highest contamination. To take advantage of the soil permeability and other site conditions, the response action was amended to include enhanced aerobic bioremediation by cometabolism. Specialty microbes were introduced into the plume in several injections over a 15-month period. This approach achieved total contaminant level reductions in the source area from 1,600 to less than 40 µg/L, and at the front edge of the plume, levels decreased from 500 to 5 µg/L. This paper presents a description of the remedial technology implementation and results.

Pilot-Scale Evaluation of In Situ Cometabolic Bioremediation of TCE in Groundwater Using PHOSter® Technology
Eggers, K.W., A. A. Rees, J. Siegal, and R.L. Hobbs. Remediation, Vol 18, No 2, p 49-66, 2008.

A study was conducted to evaluate the efficacy of PHOSter® technology for treating groundwater contaminated with trichloroethene (TCE) at Edwards Air Force Base, California. The technology consists of injecting a gaseous mixture of air, methane, and nutrients into groundwater with the objective of stimulating the growth of methanotrophs, a naturally occurring microbial group that is capable of catalyzing the aerobic degradation of chlorinated solvents into nontoxic products. Injection operations were performed at one well for a period of three months. Six monitoring wells were utilized for groundwater and wellhead vapor monitoring and for groundwater and microbial sampling. In the five monitoring wells located within 44 feet of the injection well, the following results were observed: dissolved oxygen concentrations increased to a range between 6 and 8 milligrams per liter; the biomass of target microbial groups increased by one to five orders of magnitude; and TCE concentrations decreased by an average of 92 percent, and to below the California primary maximum contaminant level (MCL; 5 micrograms per liter) in the well closest to the injection well.

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