Abstract: Regulated processes for biodegrading halogenated organic compounds in an aqueous subsurface environment through stimulation of bacteria are provided. The processes provide an electron donor source to anaerobic dehalogenating bacteria as a stimulus for biodegradation of the contaminants. When necessary to limit the biological formation of vinyl halide monomer, the processes provide for a sulfate reducing environment in the region of biological activity by the addition of an inorganic sulfate. One embodiment provides for converting the aqueous subsurface environment from anaerobic dehalogenating conditions to aerobic conditions. Another embodiment provides for converting the aqueous subsurface environment from anaerobic dehalogenating conditions to anaerobic methanogenic conditions followed by conversion to aerobic conditions in order to completely degrade the contaminants to carbon dioxide and water.