Expectations for the Performance of In Situ Chemical Oxidation: Experimental and Numerical Investigations

ABSTRACT: Only a limited set of data is available in the research literature describing the impacts of in situ chemical oxidation using permanganate on the long term reduction of contaminant concentrations in groundwater. In terms of both the removal of dense, non-aqueous phase liquids (DNAPL) and the reduction of contaminant concentrations in groundwater, three general outcomes which may be expected following an oxidant flush, along with the site-specific conditions which are likely to result in these outcomes, are presented. At many sites, attempts to manage groundwater contamination associated with the presence of dense, non-aqueous phase liquids (DNAPLs) such as trichloroethene (TCE) and perchloroethene (PCE) have met with limited success. The depth and areal distribution of DNAPLs often precludes any attempts at excavation while the effectiveness of pump and treat is limited by the low solubility of these contaminants, the weakness of dispersive mixing processes, and kinetic limitations on the rates of mass transfer from the DNAPL into the dissolved phase. Increasingly, source removal technologies such as in situ chemical oxidation (ISCO) using permanganate are deployed to aggressively remove DNAPL mass and/or reduce the concentration of the target contaminants below regulatory criteria; however, only limited data is available in the researc