Huling, S.G., B.E. Pivetz, K. Jewell, and S. Ko.
EPA 600-R-16-383, 176 pp, 2016

A pilot-scale demonstration of in situ chemical oxidation (ISCO) using sodium permanganate was performed at Site 45 to address groundwater originally contaminated with PCE. High-resolution site characterization involved multiple iterations of soil core sampling and analysis in addition to the use of nested micro-wells and conventional wells to sample groundwater for analysis of PCE and daughter products. Site impediments to ISCO activities in the source area involved subsurface utilities, including a high-pressure water main, a high-voltage power line, a communication line, and sanitary and stormwater sewer lines. A portable, low-cost, direct-push injection system was designed, constructed, and deployed at the site. Oxidant delivery deployment and design included numerous injection locations, a narrow radius of influence of the injected oxidant, short vertical-screen injection intervals, low injection pressure, outside-in oxidant injection, and a total porosity oxidant volume design. Following three oxidant injection events, significant reductions were observed in post-oxidation CVOC concentrations in groundwater and soil, and a 92% and 76% reduction in total CVOC mass flux in shallow and deep micro-wells, respectively. CVOC rebound was determined in 3 of the 38 wells, and post-oxidation PCE concentrations in one well indicated the presence of DNAPL, which suggests that rebound will continue and that additional ISCO activities are needed in the source area. Results of this study are intended to provide details and guidelines that can be used by EPA and DoD remedial project managers for planning ISCO remediation at other sites. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100SDXW.txt