The project evaluated the potential of 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-dichloroethene (DCE), and vinyl chloride. Laboratory studies were conducted to improve understanding of the microbial growth and transformation rates and to characterize important transport properties. In 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 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. 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.

"EPA/600/2-89/033." "July 1989." EPA project officer: Wayne C. Downs.