The effects of an in situ chemical oxidation (ISCO) treatment aimed predominantly at remediation of chlorinated volatile organic compounds (cVOCs) and perfluoroalkyl acids (PFAAs) co-contaminants were investigated. Soil and groundwater samples were collected before and after an ISCO pilot-scale field test of a peroxone activated persulfate (OxyZone) technology. Statistically significant decreases in PFAA groundwater concentrations were observed in post-treatment samples. Reductions in PFAA aqueous phase concentrations were also supported by decreases in soil concentrations. Importantly, there was no evidence for increased aqueous PFAA concentrations due to mobilization from soil or conversion of precursors into PFAAs. As indicated by chloride data from inside and outside the treatment zone, displacement and/or dilution could not explain the observed decrease in PFAA concentration. Also, relatively constant pH values, due to using a buffered oxidant solution, did not support increased PFAA removal via soil sorption. Overall, the use of peroxone activated persulfate to treat cVOCs had no discernible negative impacts on PFAA co-contaminants at the Site. Rather, the data suggest that PFAA concentrations decreased due to ISCO treatment.

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A methodology to enhance the containment of polycyclic aromatic hydrocarbons (PAHs) in pervious pavement systems was developed through the chemical modification of a typical Rhode Island glacial outwash soil. In addition, the PAH‐retaining capacity of different structural components of pervious pavements was evaluated using column experiments in terms of PAH retention. Two methods were used for soil amendments. The first method was a direct modification of the porous matrix using quaternary ammonium cations through an ion exchange process. The second method involved blending the soil with a commercial organoclay (PM‐199; CETCO Oil Field Services). These amendments successfully increased the soil's fraction of organic carbon (foc) by at least 70%. To quantify the efficiency of these amended soils to sorb PAHs, a series of batch isotherms and column experiments were conducted on unmodified and modified soils. These studies demonstrated that, through the synthetic modification, the sorption of PAH was increased by up to 20‐fold. The Langmuir (α, β) and Freundlich (KF, n) isotherm coefficients calculated from batch studies were higher when compared with column experiments. Overall, the organoclay‐glacial outwash blend exhibited the greatest KF value of 114.2. Breakthrough curves obtained using HYDRUS 1D were compared with measured data. The column experiments conducted on porous concrete and aggregate demonstrated that these materials have a minimal contribution to the overall containment of PAH in pervious pavement systems. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 47–54, 2014

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