ARCHIVED REPORTS_SECOND QUARTER 2013 GW MONITORING RPT

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Diamond Pet Food&Ripon Cogeneration July 12,2013 Second-Quarter 2013 Groundwater Monitoring Report Page 2 of S CONCLUSIONS The elevated TDS levels in the semiperched aquifer in the northeastern quadrant of the site, which have been up to three times higher than effluent TDS levels, are likely caused by the eucalyptus trees' concentrating effect on TDS.1 The elevated TDS levels observed along the western portion of the site,particularly in the southwest corner of the site, probably reflect the infiltration of higher TDS water originating at the City of Ripon's WWTF encroaching onto the DP/Cogen site. The elevated nitrate concentrations along the western portion of the DP/Cogen site also probably reflect the infiltration of water originating at the City of Ripon's WWTF encroaching onto the DP/Cogen site. The origin of elevated nitrate concentrations in OB-7, OB-26, and OB- 28 is unknown, although it is unlikely to be from plant activities, as these points are generally upgradient of the plants. Nitrate in the latter three wells has been stable (no trend) since the closure of Neenah paper. Overall, groundwater quality is generally stable or improving under most of the site. SITE DESCRIPTIONS AND OPERATIONS DIAMOND PET FOOD PROCESSORS OF RIPON CALIFORNIA LLC. DP uses dry ingredients, oils, fats, and fresh meat to manufacture its products. Dry ingredients consist of cereal grains, dry animal proteins, and vitamin and mineral supplements. The dry ingredients are delivered in bulk or bagged form. The bagged ingredients will be stored in a dry warehouse. The bulk ingredients will be stored in bins and silos. Fats and oils are stored in liquid tanks within a contained tank farm. The fresh meat is shipped in reusable totes and stored in a cooler room. The dry ingredients first are mixed together in a three-ton mixer, and then transferred to a hammer mill for more extensive grinding to turn into a mash. The mash is then sent to the extrusion process where the fat/oil and fresh meat are added. The extrusion process uses time, temperature, heat and pressure to cook the product. The product is cooked to a minimum of 190°F. This process creates a very small amount of scrap which is reworked or sent to an appropriate disposal facility. The product is sent from extrusion to a dryer, where it is dried for about 30 minutes. The product then moves to a series of coaters that apply fat/oil and natural flavors. The product is screened twice before it is moved to packaging. The screeners clean the product, taking off very fine pieces and mis-formed kibbles. The fines and mis-formed kibble are reworked. The product is stored in overhead bins in the warehouse until it is packaged. The product is tested in packaging and at other steps throughout the process. If the product is not within specifications, it is rejected and reworked within the process. Wastewater from the Plant consists of Reverse Osmosis (RO)reject water and process/sanitation (cleaning)water. On a maximum day, about 75,000 gallons per day(gpd) is rejected from the RO system and about 12,000 generated as process and cleaning water. This level of discharge is rare, however, occurring for one day at a time very occasionally. According to DP personnel, the maximum discharge reflects operation of all four production lines which rarely occurs. 1 G.S.Jorgensen,Kenneth H. Solomon,and V. Cervinka,March 1993,Agroforestry Systems for On-Farm Drain Water Management. 10107.04 Task 2 Lawrence&Associates W.ICLIENTSIDiamond Pet Foods1010107.01-Groundwater MonitoringlGroundwater Monitoring1201312Q201312nd quarter 2013.docx