SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

■ Lawrence Liverm 41 National Laboratory December 16, 1991 781 JAN 2 7 1992 Dear Community Member: /k!...I I- Last February, Lawrence Livermore National Laboratory (LLNL) sent you a letter to inform you about ground water cleanup work that was to begin in the eastern General Services Area (GSA) at Site 300. Site 300 is an LLNL testing site located outside of Tracy. The ground water cleanup in the eastern GSA is part of an overall site cleanup being conducted under the Federal Superfund program. This letter will update you on the progress LLNL has made on the eastern GSA cleanup in the past few months. The Ground Water Cleanup Process LLNL is treating ground water contaminated with relatively low concentrations of chemicals (trichloroethylene and tetrachloroethylene) that were used in past degreasing operations at Site 300. The contaminated ground water in the eastern GSA is present about 25 to 35 feet below the ground level and extends about 4,000 feet off the site, following the path of Corral Hollow Creek northward. No drinking water has been affected by the contamination. Water from nearby water-supply wells is sampled and analyzed every month, and has never shown any contamination. However, to retard any further movement of the chemicals and to protect water quality, LLNL is extracting and treating the contaminated ground water. The Ground Water Treatment Batem As described to you in our February mailing, the ground water treatment system consists of a well that collects the contaminated water and a tank in which the water is treated. The tank is a 2,000-gallon polyurethane unit that is mounted on a trailer. Water is sprayed into one end of the tank. As the water passes through the tank, a large blower aerates the water and strips the chemicals from it. The chemical vapors are contained within air inside the tank and are collected by filtering the tank air through two granular activated carbon canisters. The carbon canisters must be replaced periodically when the filters have absorbed their maximum amount of chemicals. The used filters are subsequently treated offsite to either destroy or recycle both the filters and the chemicals. The ground water treatment system does not release any contaminants to the atmosphere. LLNL monitors air emissions from the treatment system on a daily basis to ensure that the system is functioning properly. Full-scale operation of the ground water treatment system began in August. The system successfully treated 1,700,000 gallons of ground water during that An Equal OpporturVtyEmployer-Universityof Caflamia-PO Box 808 Livermore,Cafifdmia94550*Telephone(415)422-1100-Twx910-386-8339 UCLLL LVIVR