ARCHIVED REPORTS_THIRD QUARTER 2017 GROUNDWATER MONITORING REPORT

Home Browse Search

Diamond Pet Food&Ripon Energy October 25,2017 Third-Quarter 2017 Groundwater-Monitoring Report Page 2 of S CONCLUSIONS The past disposal of plant process water by the former paper making facility was responsible for some of the elevated TDS levels measured in the semiperched aquifer over most of the site, however, since the facility's conversion to a pet food manufacturing facility, plant effluent has never exceeded the 800 mg/L effluent limitation for TDS. The elevated TDS levels in the semiperched aquifer in the northeastern quadrant of the site, however, 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/Ripon Energy site. The elevated nitrate concentrations along the western portion of the DP/Ripon Energy site (OB- 1 and OB-5)probably reflect the infiltration of water originating at the City of Ripon's WWTF encroaching onto the DP/Ripon Energy site. The origin of elevated nitrate concentrations in 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 concentrations have fluctuated in these wells in the recent past from highs of 26.6 mg/L in OB-4 (July 1993), 88 mg/L in OB-26 (July 2008), 200 mg/L and in OB-28 (January 2008) to their current nitrate concentrations of 6.7 mg/L in OB-4, 29 mg/L in OB-26 and 51 mg/L in OB-28. The current nitrate levels in OB-26 and OB- 28 are approximately 5 to 11 times higher, respectively, than the 4.5 mg/L average effluent nitrate level in ASB-2 pond water for 2016.2 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 are stored in a dry warehouse. The bulk ingredients are 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 1 G.S.Jorgensen,Kenneth H. Solomon,and V. Cervinka,March 1993,Agroforestry Systems for On-Farm Drain Water Management. z Lawrence&Associates,January 31,2017, Combined Annual and Fourth-Quarter 2016 Groundwater-Monitoring Report,p. 3. 010107.09 Task 3 Lawrence&Associates W:CLIENTSIDiamond Pet Foods 1010107.01-Groundwater Monitoring)Groundwater Monitoring1201 713Q201 713Q quarter 2017 report.docx