Combining Technologies and Implementation Methods to Address Chlorinated Solvent Impacts at Complex Sites

Complex sites require complex solutions. Challenges typically include heterogeneous geology and contaminant mass distribution, vadose and/or saturated contaminant mass, and concentrations that span several orders of magnitude. These require us as practitioners to often consider multiple remedial technologies and approaches to reach the site specific goals within the desired timeframes. Often technologies are inefficiently implemented sequentially; this extends the remediation timeframe and requires re-characterization between remedial phases. This presentation will highlight several projects where multiple technologies were successfully implemented in concert. Technologies to be discussed include abiotic chemical reduction, enhanced reductive dechlorination, and in situ chemical oxidation. Application methods to be covered include injection via direct push, injection via permanent wells, and in situ soil blending. The strategies for each site included different approaches for source (e.g. soil blending) and plume (e.g. permeable reactive barrier) remediation.

Site #1: In the source areas, Trichloroethene (TCE) concentrations in groundwater exceeded 50 mg/L. BOS 100^®, a specialized catalyst manufactured by Remediation Products Inc., was used in the source areas. Enhanced reductive dechlorination was selected for treatment of the plume areas and involved injection of an electron donor and a dechlorinating culture.

Site #2: TCE concentrations have been detected in groundwater at a maximum concentration of 730 mg/L and in soils up to 6,800 ug/g. Soil blending was performed utilizing chemical oxidation (sodium permanganate) to treat the unsaturated TCE impacts exceeding an average 1,100 ug/g. BOS 100® was injected into the saturated zone in a barrier configuration to limit the mass flux from the source area and prevent contamination from leaving the subject property.