ARCHIVED REPORTS_SECOND QUARTER 2014 GW MONITORING RPT

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Diamond Pet Food&Ripon Cogeneration May 28,2014 Second-Quarter 2014 Groundwater Monitoring Report Page 3 of S According to DP personnel, the maximum discharge reflects operation of all four production lines which rarely occurs. The existing wastewater facilities (Sump, Clarifier, ASB-1, ASB -2, and irrigation piping) are used to treat the wastewater through aeration and disperse it. Effluent from the Clarifier is discharged into the two aeration stabilization basins in sequence (ASB-1 then ASB-2). The first pond, ASB-1, is approximately 14-feet deep and is lined; the second, ASB-2, is unlined and approximately 5-feet deep. Effluent from ASB-2 is pumped to 86 acres of fields and orchards around the site. Other ponds on the site (labeled Ponds 1 through 4) are unlined and are used only to contain excess wastewater in case of a system upset or a 100-year-or-greater storm event. RIPON COGENERATION PLANT The Cogen plant routes blowdown through the DP facilities wastewater system. The average daily flows from the Cogen in 2013 were between 11,136 and 166,790 gallons per day and the total volume of water discharged in 2013 was 42,237,830 gallons. The most recent (October 2012) TDS value for Cogen flow was 828 mg/L; previously(2010), 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 WWTF adjacent to the southwest quadrant of the DP/Cogen site. The WWTF 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 DP/Cogen 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 in the upper and intermediate aquifers along the northern and western portions of the DP/Cogen site, and have impacted wells south of the Stanislaus River. Nestl6s' consultant, Environmental Cost Management, historically operated two groundwater-treatment systems in the area to remediate the contaminant plumes, one on South Stockton Avenue and one on Industrial Avenue. The Stockton Avenue treatment systems effectively reduced the mass of contaminants in groundwater to the point where ECM was able to take the Stockton Avenue system offline on October 1, 2010. The Industrial Avenue system still is in operation. Based on the distance of the system's extraction well from the DP/Cogen site and 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 influences the hydraulic gradient in DP/Cogen wells. 010107.06 Task 2 Lawrence&Associates W.-I CLIENTSIDiamond Pet Foods 1010107.01-Groundwater Monitoring)Groundwater Monitoring120M2Q20M2st quarter 2014 report.docx