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INFORMATION SHEET 2 WASTE DISCHARGE REQUIRMENTS ORDER NO.R5-2003-0100 SPX CORPORATION,MARLEY COOLING TOWER COMPANY IN SITU GROUNDWATER REMEDIATION PILOT STUDY,SAN JOAQUIN COUNTY r chromium in the aquifer and to precipitate it out of solution,thereby immobilizing chromium. The ethanol is proposed as a carbon source to stimulate microbial growth and maintain reducing conditions to precipitate chromium out of solution. The pilot study will be conducted in two phases. The purpose of the Phase 1 pilot study is to demonstrate that injecting calcium polysulfide into groundwater will effectively reduce hexavalent chromium to trivalent chromium, and to assess the radius of influence of a single injection of calcium polysulfide. The purpose of the Phase 2 pilot study is to demonstrate the effectiveness of the multiple-injection remediation approach and the persistence of reducing conditions in the shallow groundwater plume zone. During the Phase 1 pilot study,the Discharger proposes to inject up to 5,000 gallons of 3 percent calcium polysulfide solution and 50 gallons of ethanol into injection boring INJ-1 from 60 to 80 bgs over a period of two days. In addition to the calcium polysulfide and ethanol,sodium bromide (NaBr),a non-toxic,inorganic tracer will be included in the solution at a concentration of 200 milligrams/liter(mg/1). This tracer will help to demonstrate that the observed reductions in hexavalent chromium concentrations are due to chemical reduction rather than dilution by the injected solution. Temporary wells including an injection point and six monitoring wells will be installed to supplement the existing monitoring well network. Groundwater will be monitored for hexavalent chromium(Cr VI),total Cr,bromide(Br),copper (Cu),arsenic (As),iron(Fe),manganese(Mn),sulfate(SO4),nitrate(NOA Total Dissolved Solids (TDS)and general minerals by laboratory analysis. The oxidation/reduction potential(ORP)will be measured in the field along with dissolved oxygen(DO),electrical conductance(EC), temperature,and pH. Monitoring will begin prior to the calcium polysulfide/ethanol injection, and will continue at periodic intervals until it is no longer deemed necessary. .. During the Phase 2 pilot study, the Discharger proposes to install up to 75 direct injection points into 1 to 4 different treatment zones based on the results obtained from Phase 1 study. The injection points are intended to encompass the width of the shallow chromium ` groundwater plume upgradient of the highest hexavalent chromium concentration areas. At each injection point, approximately 5,000 gallons of 3 percent calcium polysulfide solution with 50 gallons of ethanol and 200 milligrams per liter(mg/1)NaBr solution will be injected; injection volumes may be modified based on the results of the Phase 1 pilot test. The monitoring program will utilize the existing monitoring well network. Three temporary wells will be installed to supplement the existing monitoring well network. Groundwater will be monitored r for the same suite of constituents as in Phase 1 pilot study. The Water Quality Control Plan for the California Regional Water Quality Control Board Central _ Valley Region, Fourth Edition (Basin Plan), designates beneficial uses,establishes water quality objectives, and contains implementation plans and policies for all waters of the Basin. The beneficial uses the groundwater at the site are municipal and domestic supply, industrial service supply, industrial process supply, and agricultural supply. r