Site Name:

Defense Supply Center

Location:

Chesterfield County, Virginia

Period of
Operation:

December 1 - 11, 1992

Cleanup
Type:

Pilot-scale

Technology:
Soil Vapor Extraction:
- One extraction well (12 ft deep)
- Vacuum - 35 inches of water
- Air flow rate - 40 standard cubic feet per minute (scfm).

Cleanup Authority:
CERCLA
- ROD dated March 25, 1992
- ESD dated March 8, 1996

Contaminants:
Tetrachloroethene (PCE) and Trichloroethene (TCE)
Maximum concentrations measured for soil during the RI were PCE (1.5 mg/kg) and TCE (0.036 mg/kg).

Waste Source:
Disposal of wastes in open pits

Type/Quantity of Media Treated:
Soil - 1,000 cubic yards

Purpose/Significance of Application:
Pilot study of SVE for VOC contaminated soil

Regulatory Requirements/Cleanup Goals:
Soil action levels of PCE - 0.58 mg/kg and TCE - 0.20 mg/kg

Results:
- Results of soil samples collected following completion of the pilot study showed that the soil action levels had been achieved during the 10-day pilot test.
- Maximum concentrations reported for PCE - 0.18 mg/kg and for TCE - 0.11 mg/kg

Cost Factors:
Total actual cost of the pilot study was $76,099, consisting of $18,225 for capital equipment and $57,874 for operation and maintenance. - Unit cost of the pilot study treatment activities was $76/yd³ (1,000 yd³ treated).

Description:
The Defense Supply Center Richmond (DSCR) is a 565-acre installation located in Chesterfield County, Virginia, on property owned by the Department of the Army. The mission of DSCR, built in the early 1940s, is to manage and furnish general military supplies to the Armed Forces and several civilian federal agencies. In August 1987, the site was placed on the National Priorities List (NPL). A remedial investigation (RI), conducted in November 1988, identified volatile organic compounds (VOC) in the soil and groundwater in the vicinity of a pit area. While solvents or other organics were not used in these metal cleaning operations, the pits were open and may have been used for undocumented disposal of organics from other operations at DSCR. In September 1990, DSCR entered into a federal facilities agreement (FFA) with EPA and the Commonwealth of Virginia to address contamination at operable units (OU) at the site. OU 5, the Acid Neutralization Pits source area, is the focus of this report. The record of decision (ROD), signed on March 25, 1992, specified soil vapor extraction (SVE) as the remedy for OU 5 and identified cleanup goals for PCE of 0.58 mg/kg and TCE of 0.20 mg/kg.

A pilot study of SVE was conducted from December 1 to December 11, 1992, to identify additional design parameters for a full-scale system. The study consisted of two tests, a hydraulic influence test conducted over a 24-hour period, followed by a 10-day hydrocarbon removal test. For the hydrocarbon removal test, one extraction well was used along with a carbon adsorption unit for the treatment of the off-gas. The results of soil samples collected following completion of the pilot study showed that the soil action levels had been achieved during the study. The maximum concentration reported for PCE was 0.18 mg/kg and 0.11 mg/kg for TCE. An ESD was signed in March 1996 indicating that a full-scale system was not required. Covers were installed on the pits, as required in the ROD. According to the ESD, several factors contributed to the success of the pilot test, including: the actual area of contamination was smaller than originally estimated; natural attenuation may have contributed to decreased contaminant levels; and PCE concentrations in the untreated soil were only slightly higher than the cleanup goals.

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