In Situ Thermal Remediation of DNAPL Source Zones

Abstract : Groundwater contamination from chlorinated hydrocarbon (CHC) solvents released into the subsurface continues to be a persistent environmental problem at many DoD sites. This is due in part to their wide-spread historical usage. However, it is also due to the physical and chemical characteristics of those solvents. Chlorinated solvents are sparingly soluble in water, which means they can exist in the subsurface as a separate organic phase. (At the same time, the regulatory concentration limit for many of the chlorinated solvents is very low, meaning they must be addressed). That separate organic phase is more-dense than water, so most chlorinated solvents can be described as dense, non-aqueous-phase liquids (DNAPLs). The chlorinated solvents, as a group, are relatively resistant to biodegradation, and even when biodegradation does occur, the daughter products produced are also regulated as contaminants.