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California Water Quality Control Board <br /> Central Valley Region .�. <br /> 0 V)� <br /> Karl E. Longley,ScD,P.E.,Chair. <br /> Arnold <br /> Linda S.Adams 11020 Sun Center Drive 4200,Rancho Cordova,Caldornia 95670-6114 Schwarzenegger <br /> Secretaryfor Phone(916)464-3291 -FAX(916)464-4645 q �,,,,,,��� Governor <br /> Environmental http://www.waterboards,ca.govlcentralvalley <br /> Protection IU�OC \f <br /> 27 March 2009 MAR 3 1 2009 <br /> ENVIRUNh,1f:.1`C "€:'�l-�R <br /> Ms. Carol Campagna PERMi !SE`iV`OER <br /> Shell Oil Products US <br /> 20945 South Wilmington Avenue <br /> Carson, CA 90810 <br /> REMEDIATION SYSTEM IMPLEMENTATION TIMELINE AND AIR SPARGE/SOIL VAPOR <br /> EXTRACTION PILOT TEST WORK PLAN, SHELL STOCKTON TERMINAL, 3515 NAW <br /> DRIVE, STOCKTON, SAN JOAQUIN COUNTY <br /> Regional Water Quality Control Board, Central Valley Region (Regional Water Board) staff <br /> reviewed the 13 February 2009 Remediation System Implementation Timeline and Air <br /> Sparge/Soil Vapor Extraction Pilot Test Work Plan (Report) 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 Report was submitted based on the 15 December 2008 Remedial Action Plan (RAP) in <br /> which Shell proposed to implement dual phase extraction (DPE) in the three previously <br /> identified source areas (SAs) near MW-1, MW-10, and MW-13. Regional Water Board staff <br /> concurred with the RAP in our 16 January 2009 letter. The Report provides generic process <br /> flow diagrams for extracted groundwater and soil vapors, but estimates that actual remediation <br /> design would take about three months following approval. <br /> Implementation of the DPE will consist of applying a vacuum of 25-27 inches of mercury to <br /> simultaneously extract soil vapors and groundwater. Shell proposes using nine, six, and two <br /> DPE wells in SAI, SA2, and SA3, respectively. Shell will base the number and placement of <br /> DPE wells on an assumed 20-foot radius of influence (ROI). However, Shell continues to <br /> consider several options for disposing the treated groundwater that would be generated by the <br /> DPE system. Due to environmental concerns, Shell has dismissed the option of hauling the <br /> approximately 73,000 gallons per day of treated water off-site for treatment. Shell is currently <br /> considering disposal options that include (1) discharge to City of Stockton (City) sewers, <br /> (2) land disposal, or (3) re-injection. <br /> To comply with the City's sewer discharge permit limits for tertiary butyl alcohol (TBA), Shell <br /> will pursue obtaining a variance from the City. If sewer discharge is identified as a preferred <br /> option, Shell anticipates that it will need two to four months to obtain a sewer discharge permit. <br /> Shell proposes to evaluate the option of disposal to land under General Order No. R5-2003- <br /> 0044 by completing background and percolation rate studies. If this option is preferred, Shell <br /> will submit a notice of intent (NOI). Shell anticipates that receiving authorization to discharge <br /> would take three to six months. <br /> As a third option, Shell states that it is willing to conduct studies including baseline sampling <br /> and flow modeling to determine discharge limits and extraction and injection rates to re-inject <br /> California Environmental Protection Agency <br /> ea Recycled Paper <br />