Field Test of Electrokinetically-Delivered Thermally Activated Persulfate for Remediation of Chlorinated Solvents in Clay

Due to extensive industrial applications, chlorinated solvents are among the most prevalent groundwater contaminants found at hazardous sites. Given their recalcitrant nature and adverse health effects upon exposure, effective remediation technologies are needed to treat sites impacted by chlorinated solvents. In-situ chemical oxidation (ISCO) has shown success; however, its performance is often hindered in low-permeability media due to the transport of oxidants in such soils being limited. This field-scale study investigated the novel approach of applying electrokinetics (EK) to enhance the delivery of persulfate and electrical resistance heating (ERH) to activate the delivered persulfate for low-permeability soil remediation. Results demonstrated that EK has the potential to enhance delivery, where the overall mass of persulfate that was observed to be delivered into the chlorinated solvent-impacted clay formation of the field site being a factor of both EK and advection. The application of ERH to activate the delivered persulfate was found to be precluded by catalytic reactions involving naturally occurring iron. Significant chlorinated solvent reduction was observed in groundwater (\u3e80%) resulting from chemical oxidation and dilution from advective flux. To the authors’ knowledge, this was the first literature study to investigate EK and ERH for persulfate delivery and activation for low-permeability soil remediation at the field-scale