Challenges in electrochemical remediation of chlorinated solvents in natural groundwater aquifer settings

Establishment of electrochemical zones for remediation of dissolved chlorinated solvents in natural settings was studied. An undivided 1D-experimental column set-up was designed for the assessment of the influence of site-extracted contaminated groundwater flowing through a sandy aquifer material, on the execution of laboratory testing. A three-electrode system composed of palladium coated pure iron cathodes and a cast iron anode was operated at 12 mA under varying flow rates. The natural settings added complexity through a diverse groundwater chemistry and resistance in the sand. In addition, significant precipitation of iron released through anode corrosion was observed. Nevertheless, the complex system was successfully modelled with a simple geochemical model using PHREEQC. A ranking of the significances of system parameters on the laboratory execution of electrochemical remediation in natural settings was proposed: Geological properties > anode corrosion > site-extracted contaminated groundwater > the carbonate system > sulphate > hydrology > less significant unidentified parameters. This study provides insight in actual challenges that need to be overcome for in situ electrochemical remediation.