Preliminary Study on Bio-Electrokinetic Remediation of Saturated Oil-Contaminated Soil

Abstract

Bio-electrokinetic remediation of oil-contaminated soil is a promising technology. In this study, three bio-electrokinetic remediation experiments were carried out to study the effects of external addition of oil-degrading bacteria by electrokinetics and different operational parameters on oil decontamination in saturated soil. Results showed that oil in soil migrated from the anode towards the cathode with forward electroosmotic flow and accumulated near the cathode. Oil was barely degraded without external addition of oil-degrading bacteria. Although electrolytes were refreshed every 12 hr, soil pH varied greatly at the electrodes under unidirectional operation. When electrode polarity was reversed every 2 hr, soil pH was efficiently controlled within the range of 6.35-9.75. The relative oil concentrations after the bidirectional experiment were in the range of 0.81-0.84 after 20 days of treatment. The relatively low oil degradation rate may be due to the facultative aerobic environment in the saturated soil matrix.