This report contains information about the use of in situ thermal treatment technologies to treat chlorinated solvents in source zones containing free-phase contamination or high concentrations of contaminants that are either sorbed to soil or dissolved in groundwater in the saturated or unsaturated zone. Chlorinated solvent source zones have a high frequency of occurrence at hazardous waste sites. In situ thermal treatment technologies have proven to be effective in remediating source zones contaminated with chlorinated solvents, and are increasingly being used for that purpose. Specific technologies addressed are: Steam Enhanced Extraction (SEE)-In situ thermal treatment in which steam is injected into the source zone to volatilize, mobilize, or degrade contaminants; Electrical Resistive Heating (ERH)-In situ thermal treatment in which electrical current is passed through the contaminated zone, increasing the subsurface temperature based on the electrical resistance of the soil and groundwater to volatilize, mobilize, or degrade contaminants; and Thermal Conductive Heating-In situ thermal treatment in which surface or subsurface conductive heating elements are used to create a high-temperature zone to volatilize, mobilize, or degrade contaminants.

"EPA 542-R-04-010." March 2004.