A Pilot-Scale EZVI and ZVI Treatment of Unsaturated andSaturated Soil for TCE Reduction

摘要

Enhanced biological reductive dechlorination, micro-scale zero-valent iron(ZVI), and emulsified zero-valent iron (EZVI) injections were implemented to treat chlorinatedvolatile organic compounds (CVOCs) at a former manufacturing facility in westernSouth Carolina. These remedial approaches-until recently typically implemented asstandalone technologies-were combined to achieve synergistic reductions of tetrachloroethene(PCE), trichloroethene (TCE), and their reaction products. A total of38 injections were made over the course of two days in both the unsaturated and saturatedzones. The groundwater results from three shallow monitoring wells inside the injectionarea showed at least 50% reduction in dissolved concentration of PCE and TCE within ayear of injection. There was a coincident increase in the appearance of daughter productssuch as cis-1,2-dichloroethene (cis-1,2-DCE), indicating that reductive dechlorinationwas occurring. Monitoring also shows reducing conditions persist in the injection area.Analytical results from unsaturated soil sampled after the injections showed all CVOCcontaminants to be below USEPA industrial soil standards.