Soil Vapor Extraction at the Intersil/Siemens Superfund Site, Cupertino, California

Site Name:

Intersil/Siemens Superfund Site

Location:

Cupertino, California

Period of
Operation:

May 1988 to August 23, 1993

Cleanup
Type:

Full-scale Cleanup

Vendor:

Susan Colman
Geomatrix Consultants, Inc.
100 Pine Street, 10th Floor
San Francisco, CA 94111
(415) 743-7031

Technology:
Soil Vapor Extraction:
- Seven extraction wells (six installed in pairs - one in the shallow vadose zone the other in the deep vadose zone
- Three carbon bins to adsorb contaminants from the extracted soil vapor
- Air flow rates in individual wells ranged from 3 to 38 scfm (data on total system flow was not available

Cleanup Authority:
CERCLA
- ROD date: September 1990

EPA Remedial Project Manager:
Richard Procunier
U.S. EPA Region 9
75 Hawthorne Street
San Francisco, CA 94105
(415) 744-2219
Additional Contact:
State Contact:

Habte Kifle*
California Regional Water Quality Control Board
1515 Clay Street, Suite 1400
Oakland, CA 94612
(510) 622-2371

Contaminants:
Trichloroethene (TCE)

Waste Source:
Waste from the manufacture of semiconductors and related wafer fabrication

Type/Quantity of Media Treated:
Soil - 280,000 cubic yards

Purpose/Significance of Application:
SVE application using paired wells

Regulatory Requirements/Cleanup Goals:
- The ROD identified the following remedial goals for soil: total VOCs - 1 mg/kg and total SVOCs - 10 mg/kg.
- Air emissions standards for the SVE system, identified as the Bay Area Air Quality Management District, allowed an annual average of 2 pounds per day (lbs/day) of organics to be emitted.

Results:
- Total VOCs were below the remedial goal of 1 mg/kg for 79 of 80 soil boring confirmatory samples. For one sample, total VOCs was reported as 1.1 mg/kg. However, the results of an assessment of the significance of the single exceedance indicated that, with a confidence level of greater than 95 percent, the soil remedial goal was met.
- According to Geomatrix, SVOCs were not detected in any samples.
- From May 1988 to December 1992, the removal rate for TCE decreased from approximately 15.5 lbs/day to less than 0.5 lbs/day and approximately 3,000 lbs of TCE were extracted.

Cost Factors:
- Total cost of $770,000, including $550,000 in capital and $220,000 in O&M costs.
- Corresponds to a unit cost of $3 per cubic yard for 280,000 cubic yards of soil treated, and $260 per pound of contaminant removed (3,000 lbs removed).

Description:
The 12-acre Intersil/Siemens Superfund site, located in suburban Cupertino, California, includes two industrial properties used for the manufacture of semiconductors and related wafer fabrication - the Intersil facility, which operated from 1967 to 1988, and the Siemens facility, which has manufactured semiconductors at the site since 1978 and is an operating facility. The facilities used a variety of chemicals and chemical solutions in their manufacturing operations, including etching solutions, organic solvents and chemical mixtures. Soils and groundwater contaminated with volatile organic compounds (VOCs) and semivolatile organic comounds (SVOCs) were discovered on each of the sites, and several interim actions, including SVE, were implemented at the site. The site was listed on the NPL in August 1990. A Record of Decision (ROD) was signed in September 1990 that incorporated the interim remedies including SVE. This report focuses on the completed SVE application at the Intersil property. The ROD identified the following remedial goals for soil: total VOCs - 1 mg/kg and total SVOCs - 10 mg/kg. Air emissions standards for the SVE system, identified as the Bay Area Air Quality Management District, allowed an annual average of 2 pounds per day (lbs/day) of organics to be emitted.

The interim SVE system, which began operating in May 1988, included four vertical vapor extraction wells. As part of the final remedy, the SVE system was expanded in May 1991 to include three additional extraction wells. Six of the wells were installed in pairs along the eastern portion of the Intersil building - one well in the shallow vadose zone (about 10 to 50 feet deep) and the other in the deep vadose zone (about 60 to 100 feet deep). The sixth well was located along the western portion of the building. Three carbon bins were used to adsorb contaminants from the extracted soil vapor. Air flow rates in individual wells ranged from 3 to 38 scfm. According to the vendor (Geomatrix), total system flow and TCE concentrations for the total system were not available and the SVE system generally operated continuously until it was shut down (August 23, 1993). Based on the results of confirmatory soil samples, total VOCs were below the remedial goal of 1 mg/kg for 79 of 80 of the samples. For one sample, total VOCs was reported as 1.1 mg/kg. However, the results of an assessment of the significance of the single exceedance indicated that, with a confidence level of greater than 95 percent, the soil remedial goal was met. According to Geomatrix, SVOCs were not detected in any samples. From May 1988 to December 1992, the removal rate for TCE decreased from approximately 15.5 lbs/day to less than 0.5 lbs/day and approximately 3,000 lbs of TCE were extracted.

The total cost of $770,000 for this application included $550,000 in capital costs and $220,000 in O&M costs. This corresponds to a unit cost of $3 per cubic yard for 280,000 cubic yards of soil treated, and $260 per pound of contaminant removed (3,000 lbs removed).