South Carolina Dept. of Health and Environmental Control (DHEC), 12 pp, 2018

A plume of dissolved-phase PCE, TCE, cis-1,2-DCE, VC, 1,1,1-TCA, 1,1-DCE, and 1,1-DCA originates from the materials handling area of Plant 1, and a similar plume emanates from soil near the side of Plant 2. An air biosparge system installed in 2002 continues to operate at Plant 2 to prevent contaminant migration to a nearby creek. The remediation goals for the affected groundwater are the State MCLs. At Plant 1, DHEC has identified Alternative 3— enhanced reductive dechlorination (ERD) source treatment for groundwater and MNA for the dissolved-phase plume with the deed restrictions already in place—as the preferred remedy. Emulsified vegetable oil will be injected into 8 injection wells at the source area in two separate events over 2 years. The entire area will be monitored for a period of 20 years. The cost of this alternative would be about $800,000 over 20 years. At Plant 2, Alternative 4—source soil vapor extraction (SVE) and ERD, plume ERD, and the biosparge system—comprises the preferred remedy. Fifteen injection wells and 3 SVE wells in addition to a mobile site treatment unit are proposed for this area. ERD, proposed to address the dissolved plume downgradient, is to be performed using a phased approach: source area first, followed by additional injections as indicated by groundwater monitoring data. Operation of the existing biosparge system will continue. Although this alternative has a higher cost than the others, it is easily implemented, should be highly effective, and reduces the cleanup timeframe to within 10 years. The net present worth for this remedial action, adjusted for inflation through Year 10, is about $1,600,000. https://www.scdhec.gov/sites/default/files/docs/HomeAndEnvironment/Docs/LaurensCeramTec/2018-01-24_%2352_Proposed%20Plan%20for%20Site%20Remediation.pdf