ABSTRACT
Chlorinated solvents such as tetrachloroethylene, trichloroethylene, carbon tetrachloride, chloroform, 1,2-dichloroethane, and dichloromethane (methylene chloride) can exist in contaminated subsurface material as the neat oil, a component of a mixed oily waste, a solution in soil water, or a vapor in soil air. Bioventing of chlorinated solvents awaits the linkage of bioventing and the microbiology of cooxidation of the chlorinated solvents. Direct metabolism or cooxidation of chlorinated solvents ultimately produces hydrochloric acid. Many contaminated subsurface materials contain chlorinated solvents sorbed to organic materials. These materials can act as source areas for contamination of ground water or soil air and are good candidates for in-situ bioventing. Progress in bioventing is rapid, and considerable effort is being expended on the biology, physiology, and biochemistry of chlorinated solvent cooxidation in ground water. If ground-water pH is controlled by a carbonate/bicarbonate buffering system sustained by a source of carbonate in the aquifer matrix, biological activity can proceed for much longer periods of time.
