In Situ Radio‐Frequency Heating for Soil Remediation at a Former Service Station: Case Study and General Aspects

Abstract

Abstract In situ radio‐frequency heating (ISRFH) was successfully applied during remediation of a former petrol station. Using a three‐electrode array in combination with extraction wells for soil vapor extraction (SVE), pollution consisting mainly of benzene, toluene, ethylbenzene, xylenes, and mineral oil hydrocarbons (in total about 1100 kg) was eliminated from a chalk soil in the unsaturated zone. Specially designed rod electrodes allowed selective heating of a volume of approximately 480 m 3 , at a defined depth, to a mean temperature of about 50 °C. The heating drastically increased the extraction rates. After switching off ISRFH, SVE remained highly efficient for some weeks due to the heat‐retaining properties of the soil. Comparison of an optimized regime of ISRFH/SVE with conventional “cold” SVE showed a reduction of remediation time by about 80 % while keeping the total energy consumption almost constant.