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ry <br /> 79449 Riverside Drive, Suite 230, Sonoma, California 95476 <br /> CONESTOGA-ROVERS Telephone: 7079354850 Facsimile: 707935.6649 <br /> ww <br /> & ASSOCIATES w .CRAworld.com <br /> � . Gk L OD 008 <br /> �� <br /> Mr. Michael Infuma �i � �-- q U <br /> San Joaquin County Environmental Health Department <br /> OCT N 0 200$ <br /> 600 East Main Street <br /> Stockton, California 95202NVIfON `,9kIVT HERE'€# <br /> PEC, f4IT/SERVIC S <br /> Re: Remedial Options <br /> Former Shell Service Station <br /> 2575 Country Club Boulevard <br /> Stockton, California <br /> SAP Code 136144 <br /> htcident No. 98996184 <br /> SJCEHD Case No. 1071 <br /> Dear Mr. Infurna: <br /> Conestoga-Rovers & Associates (CRA) prepared this letter on behalf of Equilon Enterprises LLC dba <br /> Shell Oil Products US (Shell) to provide San Joaquin County Environmental Health Department staff an <br /> update regarding remedial options for this site. <br /> The groundwater extraction (GWE) system was shutdown on March 28, 2008 when we discovered there <br /> had been an effluent discharge of tertiary butyl alcohol (TBA) to the sanitary sewer. The discharge <br /> permit conditions placed upon Shell by the City of Stockton do not allow for TBA discharge or other fuel <br /> oxygenates into the sanitary sewer. This is the second time we have had TBA break through at this site <br /> and this is the second time the City of Stockton has issued a Notice of Violation to Shell for this site. <br /> Despite the conservative design and operational parameters of this system, we are unable to guarantee <br /> TBA won't be discharged into the sanitary sewer. Shell designs and operates all remediation systems <br /> with the intent of full compliance with permit conditions and considers permit non-compliance a very <br /> serious matter. The above considerations prompted an evaluation of upgrading the existing treatment <br /> system, as well as investigating completely different remediation technologies. Due to the restrictive <br /> nature of the discharge permit conditions and the limitations of carbon treatment for TBA our <br /> investigation has determined that an upgrade or expansion of the current carbon treatment system will not <br /> ensure permit compliance. Shell can only consider treatment technologies for this site that will ensure <br /> pernut compliance. <br /> Interim Groundwater Extraction via Batch Discharge <br /> We have completed an initial evaluation of insitu chemical oxidation (ISCO) as an alternative treatment <br /> technology for this site and this remedial approach appears to be feasible. Plans are underway to <br /> Equal <br /> Employment <br /> Opportunity Employer <br /> Worldwide Engineering, Environmental, Construction, and IT Services <br />