Contaminants:
Chlorinated and Non-Chlorinated Aliphatics - TCA (trichloroethane), DCE (1,1-dichloroethene), IPA (isopropyl alcohol), xylenes, acetone, Freon-113, and PCE (tetrachloroethene) - Maximum concentration of total solvents in soil was 4,500 mg/kg - TCA - measured as high as 3,530 mg/kg in soil; xylenes as high as 141 mg/kg in soil |
Type/Quantity of Media Treated:
Soil - 42,000 yds3 - Sands, silts, and clays; air permeability 0.12-0.83 cm/sec; transmissivity - 69,000 to 810,000 gpd/ft |
Cost Factors:
- Actual capital costs - $2,100,000 (including installation of wells and vapor extraction system, and engineering services) - Total operation and maintenance costs for 16 months - $1,800,000 (including water quality sampling and analysis, water level monitoring, equipment maintenance, engineering services, and carbon regeneration) |
Description:
The Fairchild Semiconductor Corporation Superfund site (Fairchild) is a former semiconductor manufacturing facility which operated from 1977 to 1983. In late 1981, an underground storage tank used to store organic solvent was determined to be leaking. An estimated 60,000 gallons of solvents were released to the soil and groundwater. The primary contaminants of concern in the soil were 1,1,1-trichloroethane (TCA), 1,1- dichloroethene (DCE), tetrachloroethene (PCE), xylene, acetone, Freon-113, and isopropyl alcohol (IPA). Reported concentrations of total solvents in the soil were as high as 4,500 mg/kg, with maximum concentrations of TCA and xylenes in soil of 3,530 mg/kg and 941 mg/kg, respectively. As part of a multi-site cooperative agreement between EPA, the State of California, and Fairchild, Fairchild conducted site remediation activities at the San Jose site, including installing a soil vapor extraction (SVE) system. The California Regional Water Quality Control Board established a soil cleanup goal for this remediation of a total chemical rate of less than 10 lbs/day, along with specific performance goals for individual wells.
The SVE system, which consisted of 39 extraction wells, operated from January 1989 to April 1990. The most rapid reductions in contaminant concentrations occurred during the first 2 months of operation. After 8 months of operation, the SVE system achieved the cleanup goal of less than 10 lbs/day for total chemical removed. After 16 months of operation, the system achieved a chemical removal rate of less than 4 lbs/day, at which time the system was shut off.
The total costs for the SVE treatment system at Fairchild were approximately $3,900,000. The actual costs were about 7% less than the projected costs because the time required for the cleanup was less than originally estimated. This treatment application was part of a multi- faceted cleanup program which included the installation of a slurry wall and dewatering of the aquifer which accelerated contaminant removal from the soil. |
