Enhanced reductive dechlorination of PCE in unconsolidated soils

Abstract An Interstate Technology and Regulatory Council (ITRC) forum was recently held that focused on six case studies in which bioremediation of dense nonaqueous phase liquids (DNAPLs) was performed. The objective was to demonstrate that there is credible evidence for bioremediation as a viable environmental remediation technology. A discussion of the first case study from the ITRC forum was published in the previous issue of Remediation. This article presents a discussion of the second case study, which involves enhanced reductive dechlorination (ERD) of tetrachloroethene (PCE) in unconsolidated soils—primarily silts and clays with very low permeabilities. The project results indicate that complete reductive dechlorination was achieved and provide encouragement that large amounts of nonaqueous solvent can be brought into the reductive dechlorination treatment process by dissolution and desorption, giving support to the contention that the capacity to attack nonaqueous mass is a prerequisite for any effective treatment of DNAPL source zones. The site geology for this project was relatively unfavorable, and further work is needed to confirm that the ERD technology can economically reach a natural attenuation endpoint for this type of setting. © 2006 Wiley Periodicals, Inc.