Brow, C.
British Columbia Environment Industry Association: BEST 2018, 28 slides, 2018

An electrokinetic remediation pilot test was conducted at the location of a former retail gasoline station in British Columbia, Canada, to assess the feasibility of using an electric field to facilitate the transport of nitrate as a bioremediation amendment within a silty clay aquitard. Within the 100 m² pilot area, eight electrodes were installed in two rows of four. Each electrode was constructed so it could operate as either an anode or cathode. Injection wells and monitoring wells were installed between the electrodes. The injection solution contained a mixture of ammonium nitrate, a biodegradable surfactant, and rhodamine dye. During the 7-week injection period, a constant unidirectional electric field was developed by operating one row of electrodes as cathodes and the other as anodes. Injection rates by gravity averaged 23 and 165 L/d for 1.5-in and 4-in wells, respectively, and increased to 450 and 1,320 L/d with pumping. About 14,000 L of water were extracted at the cathodes during the test, with no evidence of clay consolidation or need to inject additional water at the anodes. From the 4-in injection wells, the estimated migration rate toward the anode was 4.1 cm/d, whereas flow to the cathode and cross-field migration rates were ~1.2 cm/d. Nitrate migration rates were almost 3.5 times greater in the direction of the electric field; however, the pilot's economics suggest that the magnitude of enhancement at the site was not enough to be cost-effective. Slides: http://bceia.com/best/wp-content/uploads/2018/05/Brow-1.pdf