Laserfiche WebLink
California __�gional Water Quality <br /> Central Valley Region <br /> Karl E. Longley,SCD,P.E.,Chair <br /> Linda S.Adams }:� ;,y 1 H Arnold <br /> Secretaryjor 11020 Sun Center Drive#200,Rancho Cordova,California 9i>f ?�' Sehwarzenegger <br /> Environmental Phone(916)464-3291 •FAX(916)464-4645 PERivil I�,St,R ILES Governor <br /> Protection http://www.waterboards.ca.gov/centralvalley <br /> 31 December 2008 <br /> Ms. Shelby Lathrop <br /> ConocoPhillips Company <br /> 76 Broadway <br /> Sacramento, CA 95818 <br /> WORK PLAN FOR CONTINUATION OF MOBILE OXYGEN INJECTION AND INSTALLATION <br /> OF ADDITIONAL OXYGEN INJECTION POINTS, FORMER TOSCO BULK TERMINAL <br /> #10013, 3505 NAVY DRIVE, STOCKTON, SAN JOAQUIN COUNTY <br /> California Regional Water Quality Control Board, Central Valley Region (Regional Water Board) <br /> staff reviewed the 18 November 2008 Work Plan for Continuation of Mobile Oxygen Injection <br /> and Installation of Additional Oxygen Injection Wells (Work Plan) submitted by Stantec <br /> Consulting Corporation (Stantec) on behalf of the ConocoPhillips Company (ConocoPhillips) for <br /> the former Tosco bulk fuel terminal at 3505 Navy Drive in Stockton (Site). NuStar Energy <br /> currently owns and operates the Site. <br /> Groundwater underlying the Site is polluted with dissolved petroleum hydrocarbons. <br /> Constituents of concern (CDCs) include total petroleum hydrocarbons as gasoline (TPHg), TPH <br /> as diesel (TPHd), methyl tertiary butyl ether (MTBE), di-isopropyl ether (DIPE), and tertiary butyl <br /> alcohol (TBA). The hydrostratigraphy underlying the Site consists of three progressively deeper <br /> layers called the A, B, and C zones. The A zone occurs at depths of about 10 to 25 feet below <br /> ground surface (bgs), the B zone from 30 to 50 feet bgs, and the C zone from 55 to 75 feet bgs. <br /> ConocoPhillips conducted a 180-day oxygen injection pilot study between December 2007 and <br /> June 2008 in which bottled oxygen was injected into to 12 oxygen injection points (IP-1 through <br /> IP-12). IP-1 through IP-9 are in the A zone, and IP-10 through IP-12 are in the B zone. The <br /> objective of the pilot study was to maintain dissolved oxygen (DO) levels at 10 milligrams per <br /> liter (mg/L) or greater to enhance the biodegradation of residual COCs. Only one B zone well <br /> (P-5) consistently met or exceeded this target DO level throughout May and June. Based on <br /> these results, Regional Water Board staff met with ConocoPhillips on 27 August to discuss <br /> optimizing the delivery system, possibly using hydrogen peroxide, and installing additional <br /> injection points. At the close of the meeting, we agreed with ConocoPhillips' proposal to submit <br /> a work plan for optimization. <br /> To enhance remediation in the source area and downgradient of the Site, the Work Plan <br /> proposes to perform additional oxygen injections into a total of nine injection points, including <br /> P-10 through P-12 and six new injection points. To address the source area pollution, the Work <br /> Plan proposes to install two A zone injection points near monitoring well MW-2 and convert <br /> B zone piezometer P-6 to an injection point. To address the downgradient pollution, the Work <br /> Plan proposes to install two new injections points (one A zone and one B zone) near monitoring <br /> California Environmental Protection Agency <br /> 0a Recycled Paper <br />