Soil Remediation with Electricity

Soil Remediation with Electricity


This animation shows how St. John-Mittelhauser & Associates remediated soil contamination at a former chemical
storage facility. The drawing shows the locations of three chemical storage tanks and the associated filling pipes. A grid pattern of borings was completed
around the tanks and soil samples were collected every two feet in depth until
groundwater was encountered. Several chemicals were detected in the soils, including: perchloroethene, a dry-cleaning solvent trichloroethene, a
metal degreasing solvent and trichloroethane, a once widely used
industrial solvent. All of the solvents were combined to show the extent of
contamination. Due to the depth of the contamination, electrical resistive heating (or ERH) was determined as the most cost-effective remediation option 35 copper electrodes were installed
through the vertical extent of contamination. The inset in the upper right shows the average temperature of subsurface soils. On August 30th 2013, the remediation system was turned on, passing electricity through the
electrodes. Since soil does not conduct electricity very well the electric energy was converted to heat. As the soil temperature increased the contaminants vaporized and were vacuumed from the subsurface using co-located extraction wells. Throughout the treatment the soils were continuously sampled to ensure that the remediation goal of 10 parts per million was met. In under 10 months the project was completed and the system was turned off and removed. The photo shows an image of the ERH system in operation. For assistance with your investigation or remediation project, please email St. John-Mittelhauser & Associates or visit the SMA website at the contacts listed.

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