Electrolytic Reactive Barriers for Chlorinated Solvent Remediation

Abstract

The e-barrier is an emerging technology that applies fundamental electrochemical principles to a permeable reactive barrier (PRB). The e-barrier consists of closely spaced (e.g., 1 centimeter [cm]) permeable electrodes installed in a trench that intercepts a plume of contaminated groundwater (Figure 17.1). Low-voltage direct current (DC) sufficient to drive the degradation reactions of interest is applied to the electrodes. If sufficient electrical potential is applied, oxidizing conditions develop at the anode (positive electrode) and reducing conditions develop at the cathode (negative electrode). Since a complete electrical circuit is present, the dissolved contaminants are subject to sequential oxidation-reduction or reduction-oxidation, depending on the sequence of charges applied to the electrode set. This sequence can be altered depending on the contaminant of interest and the chemistry of the local groundwater. Through sequential oxidation-reduction (or reduction-oxidation), an aqueous phase chlorinated compound is degraded into thermodynamically favored carbon dioxide or methane and chloride.