EHC® Reagent injected via direct push across the plume area impacted primarily by PCE and TCE.
EHC was shown to effectively treat tetrachloroethylene (PCE) and its catabolites. The site is a former dry cleaning facility impacted with PCE from a historical solvent release. The source was previously excavated; however a down gradient plume showed maximum PCE concentrations of 1,400 ppb. A field scale injection of EHC took place in June 2009 with a goal to reduce the PCE mass in the distributed plume and treat any residual PCE potentially migrating from beneath the former drycleaner. A total of 1,700 lbs of EHC was injected into 18 points using direct push technologies. Subsequent field monitoring showed PCE below detection limits at all wells after 9 months, with the exception of one well at the toe of the plume (measured at 6.1 ppb). A 99.8% reduction of PCE was observed in the hot spot without the accumulation of recognized catabolites, such as DCE or VC. Upon request for site closure by the client, the CDPHE responded that “monitoring shall continue until at least two consecutive events demonstrate that inorganic parameters return to pre-treatment levels and that contaminant levels continue to remain low or non-detect”.