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Eue ,w G'. 6Ru Je. <br /> M-HEW ROD fl IOUE.'. <br /> Sf CRETRv fOn <br /> Water Boards ENVIROrnAE lir.i cROTEcIIO,: <br /> Central Valley Regional Water Quality Control Board <br /> 23 February 2015 <br /> Mr. Donald Rodgers <br /> 11900 South Union Rd. <br /> Manteca, CA 95336 <br /> IN-SITU CHEMICAL OXIDATION PILOT TEST WORK PLAN-ADDENDUM RESPONSE, THE <br /> TRANSMISSION STORE, 595 WEST CHARTER WAY, STOCKTON, SAN JOAQUIN COUNTY, <br /> CASE—#30899 <br /> California Regional Water Quality Control Board, Central Valley Region (Central Valley Water <br /> Board) staff reviewed the 22 January 2015 In-Situ Chemical Oxidation Pilot Test Work Plan—Addendum <br /> Response (Addendum Response). The Addendum Response was submitted by Advanced <br /> GeoEnvironmental, Inc (AGE) on your behalf for the underground storage tank (UST) release at <br /> 515 West Charter Way in Stockton (Site). In a letter dated 31 December 2014, Central Valley Water <br /> Board staff requested, the following: <br /> • Additional metals sampling for development of action (trigger) levels in shallow and intermediate <br /> water-bearing zones. <br /> • Background sampling from well(s) outside of the groundwater pollution. <br /> • Stoichiometric calculations to determine the volume of hydrogen peroxide (1-12O2) needed to treat <br /> petroleum pollution in groundwater. <br /> • A figure of the locations for the proposed new wells or a new work plan if addition wells are <br /> proposed. <br /> Central Valley Water Board staff also concurred with the proposal to construct two new shallow injection <br /> wells screened from 28 to 40 feet below ground surface [bgs] and two intermediate zone injection wells <br /> screened from 48 to 65 feet bgs. Due to changes proposed in the Addendum Response we understand <br /> this work will not be implemented. <br /> In the Addendum Response, AGE proposes a reduction in scope from the formerly proposed four (4) <br /> injection wells to a single injection point. In the Addendum Response, AGE recommends one (1) new <br /> shallow water-bearing zone injection well be installed near MW-7S. AGE states the single injection well <br /> will be adequate to conduct the H2O2 injection pilot test while leaving a sufficient existing monitoring well <br /> network to evaluate the effectiveness of the pilot test. <br /> Background metals for arsenic, iron, manganese, chromium, hexavalent chromium and bromate are <br /> proposed to be evaluated from groundwater samples analyzed from MW-2R, MW-4R-S , MW-7S and <br /> B4RNW-2D. MR-2R is the only well point located outside of the groundwater pollution. <br /> AGE provided stoichiometric calculations evaluating the minimum volume of H2O2 needed to treat the <br /> petroleum hydrocarbon pollution in the pilot study area groundwater. The calculations indicated a need <br /> for at least 50 gallons of 5% solution (3.0 to 3.5 grams H2O2 per gram of TPH) to address the pollutants. <br /> AGE stated that they plan to keep the Work Plan proposal to inject 200 gallons (four times the minimum <br /> KAOL E. LONOLEY SCD, P.E., alAIR I PAIArLA C. Cf1EEDON P.E., BCEE, EXECUTIVE orrlcrn <br /> 11020 Sun Center Drive#200.Rancho Cordova,CA 95670 1 www.waterboards.ca.gov/centralvalley <br /> 0 fleCYOItD rnfen <br />