Publication Date:
2012-07-10
Description:
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. In situ radio-frequency heating (ISFRH) in combination with soil vapor extraction was successfully applied for remediation of a decom-missioned petrol station in Manston/Kent, UK. The technical and engineering aspects of the described demonstration project can be analogously applied at other sites. With respect to energy and total costs, the ISRFH method has a good chance to compete with alter-natives.
Print ISSN:
0930-7516
Electronic ISSN:
1521-4125
Topics:
Chemistry and Pharmacology
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Process Engineering, Biotechnology, Nutrition Technology
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