Electrokinetic Soil Remediation for Canadian Northern Regions

Permafrost soils may have been polluted by pipeline spills due to the increasing rate of ice cap thawing as a consequence of climate change. Thus, an adequate treatment of such soil should be developed. This study aimed to investigate the feasibility of applying electrokinetic remediation to organic soil polluted with hydrocarbon in cold regions. A series of tests were conducted at 7 °C in electrokinetic cells (EK) containing 120 g of soil simulating peat properties. Synthetic soil samples consisted of 35% organic matter, 3% clay, and 62% sand. Soil samples were contaminated by toluene (40 mg/kg dry mass), as a hydrocarbon representative, above an acceptable level (Schedule II) of Quebec regulations. A soil electro-washing system with an average of 100 mL of surfactant solution/day was applied to mobilize pollutants toward the cathode or anode. Results showed the toluene removal in the liquid samples accompanied by some soil organic fraction (e.g., humic substances) during a 5-day test at a constant low voltage gradient of 2 V/cm. The observed removal of toluene in cold temperatures was many times higher than in an ambient temperature showing a high potential for electrokinetic remediation for cold regions.