ARCHIVED REPORTS_SECOND HALF AND ANNUAL 2010 GW MONITORING RPT

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Diamond Pet Food Processors of Ripon California LLC January 28, 2011 Combined Annual and Fourth-Ouarter 2010 Groundwater Monitoring Report Page 7 of 8 The third season of applying low TDS water to the east percolation field began on August 3, 2009, and ended on September 23, 2009. A total of 21.77 acre feet (7.1 million gallons) of water from production well PW-6 were placed on DP's east percolation field. During 2010, low TDS water was not applied to the east percolation field, however, all process water that was applied around the remainder of the site contained TDS concentrations below the 713 mg/L WQPS established for the semiperched aquifer(Attachment Q. Conclusions Groundwater quality has continued to improve across the southeast and central portions of the DP site as the result of(1) recharging the semiperched aquifer underlying the east percolation field with low TDS surface water during the irrigation seasons of 2007 and 2008 and with low TDS groundwater during the 2009 irrigation season; and (2) discontinuing paper production at the mill that has reduced TDS loading to the semiperched aquifer by 3,676 pounds per day based on average 2008 mill production. Groundwater with TDS levels higher than WQPS is encroaching in the southwest quadrant of the DP site as recharge from the City of Ripon's MWWTF moves easterly towards the DP site. Site Descriptions and Operations Diamond Pet Food Processors of Ripon California LLC. The DP site is located next to the Stanislaus River in Ripon, California. There is an electric- power cogeneration plant adjacent to the Mill. Previously, both the Mill and the Cogen plant were owned by Simpson Paper Company; now, however, the Cogen plant is owned by Fort Chicago US Power Inc. The Cogen plant contributes approximately 300,000 gallons of water containing approximately 1,000 mg/L TDS to DP's waste stream per day. It should be noted that DP has no direct control of the operations of the Cogen plant or the quality or quantity of wastewater it receives from the Cogen plant. Mill operations have been described in the WDR and other documents. Briefly, prior to its closure, the Mill manufactured several grades of fine papers from purchased pulps. Process water was added to the pulps to make a pulp slurry which then was made into paper. Effluent from this process, along with some regeneration brine from the Cogen plant, was collected and discharged into a primary clarifier. The mill ceased manufacturing paper on May 22, 2009, and has no plans for resuming operations. Now that the mill is idle, it no longer produces an effluent stream. Currently, the regeneration brine from the Cogen plant still is discharged to the clarifier where it is blended with low TDS water from PW-6 before being discharged into two aeration basins, in sequence (ASB-1 and 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 irrigation and percolation fields around the site. City of Ripon The City of Ripon operates a MWWTF adjacent to the southwest quadrant of the DP site. The MWWTF treats an average of 1,000,000 gallons of domestic effluent per day. The system consists of a series of clay-lined ponds with surface mechanical aeration system to oxygenate the waste water. Treated effluent water is disposed by percolation from 45 acres of disposal ponds. 10107.01 Task.2 Lawrence S Associates R:I CLIENTSI Diamond Pet Foods1010107.01-Groundwater Monitaringl Groundnmter Monitoring12010t 2nd Half 20101annual-2nd Half 2010 repamdoc