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California Regional Water Quality Control Board <br /> Central Valley Region : =j <br /> Robert Schneider, Chair <br /> Linda S.Adams Arnold <br /> Secretar�,jor Sacramento Main Office Schwarzenegger <br /> Environmento( 11020 Sun Center Drive#200,Rancho Cordova,California 95670-6114 Governor <br /> Protection Phone(916)464-3291 •FAX(916)464-4645 <br /> hitp://www.waterboards.ca.gov/centralvalley <br /> �IrF I VHJ <br /> 21 July 2006 fill 4 2006 <br /> Mr. Thomas Kosel <br /> ConocoPhillips Company <br /> 76 Broadway <br /> Sacramento, CA 95818 <br /> REVIEW OF OXYGEN INJECTION PILOT TEST WORK PLAN, FORMER TOSCO BULK <br /> TERMINAL #10013, 3505 NAVY DRIVE, STOCKTON, SAN JOAQUIN COUNTY <br /> Staff of the California Regional Water Quality Control Board, Central Valley Region (Regional <br /> Water Board) has reviewed the 4 April 2006 Work Plan for Oxygen Injection Pilot Test, Former <br /> Tosco Bulk Terminal No. 10013 (Work Plan) submitted by Earth Tech, Inc. (Earth Tech) on <br /> behalf of ConocoPhillips Company (ConocoPhillips) for the former Tosco bulk fuel terminal site <br /> at 3505 Navy Drive in Stockton, San Joaquin County (Site). ConocoPhillips proposes a six- <br /> month pilot test to evaluate the feasibility of remediating petroleum hydrocarbons and fuel <br /> oxygenates dissolved in groundwater using oxygen injection. ConocoPhillips currently <br /> operates a groundwater extraction and treatment system (GWETS) utilizing a HiPOx system, a <br /> combination of hydrogen peroxide and ozone treatment. Use of the GWETS and HiPOx <br /> system has reportedly reached its limitation in treating residual concentrations of methyl butyl <br /> ether (MTBE) and tertiary butyl alcohol (TBA) dissolved in groundwater beneath the Site. <br /> Oxygen injection is proposed to enhance aerobic biodegradation of these compounds. <br /> Decommissioning of the HiPOx system is planned prior to construction of the pilot test system. <br /> ConocoPhillips proposes conducting the oxygen injection pilot test utilizing an injection well <br /> network in the area where groundwater MTBE and TBA concentrations are highest. The <br /> depth to groundwater is approximately 10 feet below ground surface (bgs). Six shallow <br /> injection wells will be installed near monitoring well MW-8 and three shallow injection wells will <br /> be installed near well MW-2. Three deep injection wells will be installed near well MW-14. <br /> Drilling for the well installations will be accomplished using hollow-stem auger equipment. The <br /> 1-inch-diameter polyvinyl chloride (PVC) shallow wells will be completed at 25 feet bgs with a <br /> 12-inch-long well screen containing 0.010-inch slots. The deep injection wells will be similarly <br /> constructed and completed at 50 feet bgs. Filter pack sand will be placed to about 1 foot <br /> above the top of the well screen and a 2- foot to 3-foot thick bentonite seal will be placed <br /> above the filter pack. The remaining annulus will be backfilled with neat cement to about 2 <br /> feet bgs to allow for connection of oxygen delivery piping. The wellheads will be completed in <br /> watertight traffic-rated well boxes. <br /> Oxygen will be produced using a trailer-mounted pressure-swing adsorption oxygen generator <br /> capable of 30 standard cubic feet per hour (SCFH) and delivered to the injection wells using a <br /> compressor. The system will be operated using a new 30-amp electrical power drop utilizing <br /> California Environmental Protection Agency <br /> 0a Recycled Poper <br />