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California Regional Water Quality Control Board <br /> \% • Central Valley <br /> g Re ion <br /> Karl E. Longley,ScD,P.E.,Chair �,,,:.:.••. <br /> Linda S.Adams Arnold <br /> Secrelaryfor 11020 Sun Center Drive#2O0,Rancho Cordova,California 95670-6114 Schwarzenegger <br /> Environmental Phone(916)464-3291 •FAX(916)4644645 <br /> Governor <br /> Praleclion <br /> http://www.waterbowds.ca.gov/centralvalley <br /> 16 September 2009 <br /> SEP 1 8 2009 <br /> Mr. James Taylor ENV(R() <br /> Continental Grain Company N,ERoNmfh1NMENTHEALTH <br /> AON Center <br /> 200 E. Randolph Street, Suite 600 <br /> Chicago IL 60601-6436 <br /> CONCURRENCE WITH GROUNDWATER RECIRCULATION PLAN, FRENCH CAMP <br /> GRAIN ELEVATOR, 9504 S. HARLAN ROAD, SAN JOAQUIN COUNTY <br /> Constituents of concern in groundwater at the French .Camp Grain Elevator are carbon <br /> tetrachloride, chloroform, 1,2-dichloropropane and 1,2,3-trichloropropane. The greatest mass <br /> of contaminants is in the second water-bearing zone, about 60 to 80 feet below ground <br /> surface (bgs). In 2005, Continental Grain Company (Continental) injected zero valent iron into <br /> the subsurface, intersecting the second water-bearing zone. Pursuant to its February 2007 <br /> Groundwater Recirculation Remediation Plan (2007 Work Plan) and California Regional Water <br /> Quality Control Board, Central Valley Region (Central Valley Water Board) staff's 4 October <br /> 2007 conditional concurrence letter, Continental operated a groundwater recirculation pilot <br /> study in 2008 and 2009 for one of its two injection/extraction well pairs. This pilot study <br /> evaluated the potential to extract groundwater downgradient of the zero valent iron and <br /> reinject polluted groundwater such that it flows through the iron. The pilot study demonstrated <br /> that groundwater recirculation through the iron accelerates the rate of constituent destruction <br /> without causing groundwater mounding. <br /> In order to operate both injection/extraction well pairs concurrently, Continental has provided a <br /> May 2009 Notice of Intent prepared by its consultant, Huff & Huff Inc. This Notice of Intent <br /> provides an updated 2007 Work Plan and requests enrollment in Waste Discharge <br /> Requirements General Order No. R5-2007-0149 for In-Situ Groundwater Remediation at Sites <br /> with Volatile Organic Compounds, Nitrogen Compounds, Perchlorate, Pesticides, Semi- <br /> Volatile Compounds, Hexavalent Chromium and /or Petroleum Hydrocarbons (In-Situ General <br /> Order). <br /> Updated Work Plan <br /> As presented in the May 2009 Notice of Intent, the 2007 Work Plan is updated to reflect data <br /> obtained since the recirculation pilot system has been in operation, and proposes to operate <br /> both injection/extraction systems simultaneously at rates of up to 6 gallons per minute (gpm) <br /> each. The injection/extraction points of the second well pair is about 90 feet away from the <br /> injection/extraction points of the first well pair. <br /> California Environmental Protection Agency <br /> co Recycled Paper <br />