ABSTRACT
The use of electric fields has emerged as an innovative method for in-situ restoration of contaminated hazardous waste sites. Direct currents (DC) are applied across electrodes inserted in the soil to generate an electric field for mobilization and extraction of contaminants and for biogeochemical modifications of polluted soils and slurries. The driving mechanisms for this technique, known as electrokinetic remediation, are transport under electric fields (in particular, electroosmosis and ionic migration) coupled with electrolysis and geochemical reactions. Extraction and removal are generally achieved by electrodeposition, precipitation, or ion exchange (for heavy metals), and collection and treatment of organics in external systems. Contaminants that could be treated by electric field applications include inorganic, organic, and radioactive compounds that are charged (ionic) or noncharged (polar and nonpolar). This chapter provides a review of the fundamentals and applications of electrokinetic remediation. The chapter describes the general electrokinetic and transport phenomena in soil under electric fields, followed by identification of electrolysis and geochemical reactions associated with application of electric fields in soils. Finally, current technology status and considerations for practical implementation of the technology are presented.
