f Electrical Resistance Tomography During In Situ Remediation Of A Tce Plume At The U.S. Department Of Energy Savannah River Site

The Savannah River Integrated Demonstration Project was undertaken by the Department of Energy (DOE) to demonstrate the remediation of volatile, organic compounds from saturated and<br>unsaturated soil horizons at the Savannah River Site, South Carolina. A dilute mixture of air and methane was pumped into a horizontal well that was drilled in the contaminated zone. Methane was intended as a nutrient for native populations of microorganisms whose metabolic products degrade the TCE. A horizontal vacuum extraction well was installed in the vadose zone to remove solvent vapors that had been stripped from the vadose zone. The experimental site consisted of alternating units of permeable sands with low fines content and significantly less permeable clayey sand and clay units. Generally, the clays tended to be thin and discontinuous. Cross borehole electrical resistance tomography was done in 4 planes<br>near the air-methane injection well to determine the extent and dynamics of the gas plume below the water table. Tomographs were done before gas injection began, then soon after injection began and again after gas had been flowing for four months.