Laserfiche WebLink
s � <br /> INFORMATION SHEET <br /> WASTE DISCHARGE REQUIREMENTS ORDER NO. R5-2003-XXXX <br /> LINCOLN CENTER ENVIRONMENTAL REMEDIATION TRUST <br /> IN-SITU GROUNDWATER REMEDIATION PILOT STUDY <br /> SAN JOAQUIN COUNTY <br /> The Lincoln Center Environmental Remediation Trust (hereafter"Discharger") is responsible for <br /> administering a site cleanup fund, established pursuant to the settlement of a lawsuit in the United <br /> States District Court, Eastern District of California, for the remediation of contaminated soil and <br /> groundwater. The contamination resulted from the release to the environment of dry cleaning <br /> chemicals (primarily perchloroethene or PCE) at the Lincoln Center Shopping Complex in <br /> Stockton, California. The maximum PCE level measured in recent groundwater sampling is 9,500 <br /> micrograms/liter(µg/l). The plume of polluted in groundwater extends approximately 1400 feet <br /> east of Lincoln Center. The Discharger operates a soil vapor extraction system (SVE) and a <br /> groundwater extraction and treatment system at the site. <br /> The SVE system consists of 35 SVE wells located in the area of highest concentrations of PCE in <br /> the soil gas. The contaminated soil gas is extracted under vacuum and treated by vapor phase <br /> granular activated carbon(GAC). The system presently operates at 2000 standard cubic feet/min <br /> with an influent PCE vapor concentratioh of 500 ppbv (04/2003). To date, the SVE system has <br /> removed over 6500 pounds of PCE from the vadose zone. The groundwater extraction and <br /> treatment system consists of 23 extraction wells in the shallow zone of the aquifer(the "A"zone) <br /> and 10 extraction wells in the next deeper zone of the aquifer(the "B"zone). The extracted <br /> groundwater is treated by air stripping, liquid phase GAC and is then discharged to the storm drain <br /> pursuant to WDR Order #98-062 (NPDES #CA0084255). The system presently operates at 230 <br /> gallons/minute with an influent PCE concentration of 850 ug/1 (03/2003). To date, the <br /> groundwater extraction and treatment system has removed over 2825 pounds of PCE from <br /> groundwater. <br /> The Discharger is evaluating alternatives to accelerate the cleanup of the polluted groundwater <br /> including in-situ chemical reduction of PCE. The Discharger submitted a Report of Waste <br /> Discharge (ROWD) and a"Bench Scale Treatability Study and Pilot Study Work Plan, Historical <br /> Source Area"on March 21, 2003 for a proposed in-situ groundwater remediation pilot study. The <br /> objective of the pilot study is to evaluate the efficacy of in-situ PCE reduction in low permeability <br /> sediments by injection of liquid nitrogen to pneumatically fracture the low permeability sediments, <br /> followed by the injection of granular zero-valent iron (GZVI) powder. GZVI is a strong reducing <br /> agent. Electrons released during GZVI oxidation reduce the chlorinated solvent compound <br /> whereby the chlorine atoms are replaced by hydrogen. During the reductive dechlorination, PCE <br /> and subsequent daughter products act as electron acceptors. The reaction series from PCE to <br /> ethene is as follows: <br /> PCE >TCE > cis-dichloroethene >vinyl chloride > ethene <br /> The hydronuim ion (affecting pH) and chlorine are also produced in this reaction. <br /> i <br />