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California conal Water Quality Cont Board ' <br /> Central Valley Region s7 H <br /> Karl E. Longley,ScD, P.E.,Chair. Arnold <br /> Linda S. Adams ,yL,IL�020 Sun Center Drive N200.Rancho Cordova.California 95670-6114 Schwarzenegger <br /> Seoemp-jor Inl 1�— � ��(q;Ih3r1(z4.]291 •FAX(916)464-4645 - Governor <br /> Fnvirownemal �IOI;-'�❑f lLr��IIV_ t1111,,�L1[//,((JJL�LS- LIt boards.ca.govlcentraivalle) <br /> Protecuon <br /> 16 January 2009 JAN 2 0 2009 <br /> ENVIRONMENT HEALTH <br /> Ms. Carol Campagna <br /> PERMIT/SERVICES <br /> Shell Oil Products US <br /> 20945 South Wilmington Avenue <br /> Carson, CA 90810 <br /> REMEDIAL ACTION PLAN, SHELL STOCKTON TERMINAL, 3515 NAVY DRIVE, <br /> STOCKTON, SAN JOAQUIN COUNTY <br /> Regional Water Quality Control Board, Central Valley Region (Regional Water Board) staff <br /> reviewed the 15 December 2008 Remedial Action Plan (RAP) submitted by Conestoga-Rovers <br /> and Associates (CRA) on behalf of Shell Oil Products US (Shell) for the Shell Stockton <br /> Terminal at 3515 Navy Drive in Stockton (Site). <br /> The RAP was submitted based on results reported in the 30 September 2008 Dual-Phase <br /> Extraction Pilot Test Report (Pilot Test Report) in which Shell calculated that a removal rate for <br /> total petroleum hydrocarbons as gasoline (TPHg) of about 255 pounds per day was <br /> achievable at the maximum encountered TPHg concentration of 24,000 parts per million by <br /> volume. Regional Water Board staff concurred with Shell's conclusions in the Pilot Test Report <br /> and requested a RAP for full-scale implementation of this technology. <br /> The RAP proposes to implement dual phase extraction (DPE) in the three previously identified <br /> source areas (SAs) near MW-1 , MW-10, and MW-13. Shell will submit a work plan detailing <br /> the number of extraction wells required to dewater each SA. In teleconference discussions on <br /> 29 November and 14 December 2007, Shell stated that extracted groundwater would be <br /> stored in holding tanks and transferred to its refinery in Martinez for treatment and disposal. <br /> However, the RAP proposes to pump extracted groundwater into a transfer tank, then filter it <br /> through a series of silt filters and carbon vessels prior to discharge. Operational parameters, <br /> including groundwater flow rate and depth to water in DPE and monitoring wells, will be <br /> measured during semi-monthly operation and maintenance site visits. Influent, mid-point, and <br /> effluent water samples will be collected from the carbon vessels during and after startup. The <br /> normal operation sampling schedule has not yet been determined. <br /> The RAP explains that Shell requested an extension of the due date for the RAP to <br /> accommodate a re-evaluation of air sparging and soil vapor extraction (AS/SVE) based on <br /> data showing the soil formation may be more permeable than previously thought. Regional <br /> Water Board staff denied the request for the extension, so Shell submitted the RAP for DPE <br /> and is concurrently re-evaluating AS/SVE as an alternate remedial technology. <br /> For the DPE system, extracted soil vapors will be conveyed though an entrainment separator <br /> to remove condensate from the vapor stream. The condensate will be sent to an on-site <br /> treatment system. The vapors will be routed to an oxidizer for treatment; the oxidizer can be <br /> operated in either thermal or catalytic mode, depending on the influent vapor concentrations. <br /> California Environmental Protection Agency <br /> Cr} Req cled Paper <br />