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Project Summary. IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA
Citation:
Roberts, P., L. Simprini, G. Hopkins, D. GrbicGalic, P. McCarty, AND M. Reinhard. Project Summary. IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA. EPA/600/S2-89/033, 1989.
Impact/Purpose:
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Description:
This project evaluated the potential of an innovative approach to aquifer restoration: enhanced in-situ biotransformation of chlorinated aliphatic solvents by a bacterial community grown on methane under aerobic conditions. The target chlorinated compounds were trichloroethene (TCE), cis- and trans-1,2-dlchloroethene (DCE), and vinyl chloride (VC). Laboratory studies were conducted to improve understanding of the microbial growth and transformation rates and to characterize important transport properties. In the field experiments, biostimulation was accomplished by introducing methane and oxygen into a shallow, confined, sand and gravel aquifer to encourage the growth of a native bacterial community. Methane utilization commenced rapidly, within ten days in the first biostimulation attempt, and within one day in subsequent biostimulation episodes. Biotransformation of the target organic compounds ensued immediately after commencement of methane utilization, and reached steady-state values within three weeks. The approximate extents of transformation were as follows: VC, 95%; trans-DCE, 85%; cis-DCE, 40%; and TCE, 20%.These amounts of biotransformation were achieved in a relatively small biostlmulated zone, with travel distances of 1 to 4 m and travel times of 8 to 25 hrs. Mathematical modeling of the transport and transformation process confirmed that the behavior observed in the field demonstration was consistent with the results of the laboratory research and theoretical expectations. This technology has been demonstrated to be effective In continuous operation under carefully controlled condtttens in a real subsurface environment at small scale, and is a viable candidate for consideration at real contamination sites where conditions are favorable.
URLs/Downloads:
URL.PDF (PDF, NA pp, 22 KB, about PDF)Project Summary. IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA