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 12 of 17 For the following analysis, two scenarios were evaluted—one with the cogeneration plant in operation and one without the cogeneration plant. In the latter scenario, it is assumed that the cogen plant can continue to supply Diamond with distilled water for their operations. POTENTIAL FOR IMPAIRMENT OF SURFACE WATERS The nearest surface-water body is the Stanislaus River, forming the southern boundary of the site. If the irrigation fields overflowed, the discharge would flow into the Stanislaus River. Historically, the irrigation fields have not overflowed into the river. Because the proposed maximum discharge is less than 20% of the volume of the previous discharge (maximum 455,000 gpd vs. 2,500,000 gpd previously) it is unlikely that the irrigation fields could not accommodate the combined Diamond/Cogen discharge. POTENTIAL FOR IMPAIRMENT OF GROUNDWATER The potential for impairment of groundwater would come from infiltration of the wastewater applied to the irrigation fields and leakage through ASB-2. The potential for groundwater impairment was evaluted using the existing groundwater model for the site and by calculating the mass loading of TDS from facility operations. The groundwater model previously was developed for the site to evaluate alternatives for corrective action for impacts related to dispersal of wastewater from Fox River Paper Company and Neenah Paper Company. Appendix B contains a description of the model. Previous and current site activities (dispersal of paper-mill process wastewater mixed with cogen blowdown), and vicinity discharges (City of Ripon WWTP ponds,Nestles' spill), have affected groundwater quality. Historic discharge at the site contributed about 8,100 lbs/day of TDS to the semiperched aquifer(about 1,187,000 gpd at a TDS of about 814 mg/L). Recently (second-half 2010), after paper-mill operations ceased, TDS loading (from operation of the cogen and mixing groundwater with that effluent)has been about 2,000 lbs/day (about 429,000 gpd at a TDS of about 565 mg/L). The proposed operation,plus cogen discharge, will contribute approximately 3,050 lbs/day of TDS to the semiperched aquifer(about 455,000 gpd at a TDS of about 800 mg/L). The proposed operation, without the cogen discharge (after 2017), will contribute approximately 900 lbs/day of TDS to the semiperched aquifer(about 159,000 gpd at a TDS of about 660 mg/L). This is almost 10 times less than the previous combined paper-mill and cogen operations, and is about one- third the amount of the TDS imparted from the combined Diamond and cogen operations. 010107.00, Task I Lawrence&Associates w:Iclientsl diamond pet foods1010107.00-ripon rowdldiamondpet_rowdjune2011_draft.docx