ARCHIVED REPORTS_RPT OF WASTE DISCHARGE FOR WASTEWATER DISPERSAL 2011

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Diamond Pet Food Processors of Ripon,LLC June 30,2011 Report of Waste Discharge Page 4 of 17 FORT CHICAGO US POWER COGENERATION PLANT The adjacent cogeneration plant historically has routed blowdown through the Diamond facilities wastewater system, and will continue to do so until 2017. In 2017, the cogen will either convert to an air-cooled system(therefore eliminating blowdown discharge) or cease operations. Figures 4 and 5 show recent(2009 and 20 10) data from flow and quality monitoring, respectively, of the cogen discharge. Recent flows have been between 200,000 and 300,000 gallons per day. The most recent (late 20 10) quality data is not available,but previously in 2010 total dissolved solids (TDS) in the cogen discharge ranged between 500 and 1,200 mg/L. Historically, the cogen flow was blended with lower TDS paper-mill effluent before being discharged, in sequence, into the two aeration basins (ASB-1 and ASB-2)before being pumped to irrigation and percolation fields around the site for disposal. After the paper mill closed(May 2009), the cogen discharge was blended with water pumped from production well PW-6 before being dispersed to the irrigation fields. CITY OF RIPON The City of Ripon operates a municipal wastewater treatment facility(MWWTF) adjacent to the southwest quadrant of the Diamond site. The MWWTF treats an average of 1.0 million gallons per day(MGD). The system consists of a series of clay-lined ponds with a surface mechanical aeration system to oxygenate the waste water. Treated effluent water is disposed by percolation from 45 acres of disposal ponds. The City is currently under directive from the CVRWQCB to evaluate the impacts of effluent disposal on groundwater quality. NESTLES Nestl6s USA formerly operated an instant coffee and tea processing plant, located approximately 2,000 feet north of the Diamond site, from 1948 through 1986. Solvents used in the decaffeination process, and their daughter products (trichloroethene, dichloroethene, and vinyl chloride) have impacted soils at the site and groundwater throughout the Ripon area. Nestles' consultant, Environmental Cost Management, currently operates a groundwater-treatment system in the area to remediate the contaminant plumes. The plumes have impacted the upper and intermediate aquifers along the northern and western portions of the Diamond site, and have impacted wells south of the Stanislaus River. Based on the distance of the remediation system's extraction wells from Diamond, the volume of water treated by the system(<500 gpm), and the relatively high permeability of the aquifer, it is unlikely that the extraction system would influence the hydraulic gradient in the Diamond wells. The 010107.00, Task I Lawrence&Associates w:Iclientsl diamond pet foods1010107.00-ripon rowdldiamondpet_rowdjune2011_draft.docx