Electrokinetic remediation: Technology status

The demand to develop innovative and cost-effective in-situ remediation technologies in waste management stimulated the effort to employ conduction phenomena in soils using an electric field to remove chemical species from soils. This technique variably named as electrokinetic remediation, electro-reclamation, electrokinetic soil processing, electrochemical decontamination, electrorestoration or electrochemical soil processing uses low-level DC in the order of mA/cm{sub 2} of cross sectional area between the electrodes or an electric potential difference in the order of a few volts per cm across electrodes placed in the ground in an open flow arrangement. The low-level DC results in physico-chemical and hydrological changes in the soil mass leading to species transport by coupled and uncoupled conduction phenomena in the porous media. Electrolysis reactions prevail at the electrodes. The species input into the system at the electrodes (either by the electrolysis reactions, or through the cycling processing fluid) and the species in the pore fluid will be transported across the porous media by conduction phenomena in soils under electric fields. This transport coupled with sorption, precipitation and dissolution reactions comprise the fundamental mechanisms affecting the electrokinetic remediation process. Electrokinetics Inc. of Baton Rouge has completed large-scale pilot studies using spiked and naturally contaminated soilmore » deposits under the USEPA SITE program. In collaboration with the US Army Waterways Experiment Station, Electrokinetics Inc. is currently carrying out a field study of extracting lead from soils at a Firing Range that belongs to the US Army. This demonstration study will be independently evaluated by the USEPA under the SITE program. The purpose of this paper is to present some of the recent developments in this technique and to outline the ongoing activities.« less