Electrokinetic remediation of soils at complex contaminated sites: Technology status, challenges, and opportunities

Subsurface contamination has become a widespread and pervasive global problem. Heavy metals and organic compounds often coexist, and such mixed contaminant distribution within the subsurface is highly dependent on particle and macro-scale heterogeneities. Vast amounts of resources have been invested to develop efficient remediation technologies, yet few have been successful. In-situ remediation is often preferred due to lower site disturbance, safety, simplicity, and cost-effectiveness. However, the effectiveness of in-situ technologies depends largely on contaminant chemistry and subsurface heterogeneities (including particle-scale heterogeneities, e. g. fine-grained soils, soils with reactive minerals and/or organic matter, and macro-scale heterogeneities, e. g. irregular soil layers and/or lenses). Under complex site and contaminant conditions, electrokinetic remediation has great potential. This paper presents the status of this technology based on numerous laboratory investigations and limited field demonstrations, the challenges in applying this technology at actual field sites and opportunities for electrokinetics as an efficient and economical remedy for complex contaminated sites.