ARCHIVED REPORTS_2011 REVISED FEASABILITY STUDY

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Nestle USA, Inc.—Ripon, CA January 28, 2011 2011 Revised Feasibility Study Currently, the City of Ripon WWTP receives an average domestic inflow of 1.2 MGD, which is treated via aeration in a series of lined ponds and then allowed to percolate to the subsurface in nine percolation/evaporation disposal basins as shown in Figure 3. Industrial wastewater inflows are routed directly to the percolation/evaporation disposal ponds in the southern portion of the WWTP and to two infiltration basins west of the domestic storage ponds, as shown in Figure 3. In contrast to domestic wastewater, industrial wastewater is percolated directly to the subsurface via these infiltration ponds and basins. Industrial wastewater does not undergo treatment through aeration basins. Industrial discharges to the WWTP have consisted of effluent from private commercial and industrial facilities Data from groundwater monitoring wells near the City of Ripon WWTP lagoons do not reveal a significant presence of COCs in the Upper Aquifer'" Upper Aquifer monitoring wells in the area of the WWTP show TCE and VC concentrations below 5 pg/L during the most recent 2009 sampling events. The highest COC concentration in 2008 in Upper Aquifer wells near the WWTP was a detection of 6.7 pg/L of cis-1,2-DCE in well M-23A. Groundwater in the Intermediate Aquifer, however, has exhibited relatively more elevated COC detections, ranging up to 43 pg/L TCE, 260 pg/L cis-1,2-DCE, and 180 pg/L VC in wells near the WWTP. The updated SCM concludes that the COC impacts to the Intermediate Aquifer appear to be due to: • Groundwater mounding that has induced steep vertical gradients that may have caused movement of CDCs from the percolation ponds and Upper Aquifer into the Intermediate Aquifer. • Changes in surface infiltration caused by seasonal and annual precipitation, and the stages of the River, which increase vertical gradient and influence COC movement. • The presence of various active and inactive wells (NPC wells and independent agricultural operators) may have provided conduits for the vertical migration of COCs from the Upper Aquifer to the Intermediate and Lower Aquifers. • Historical pumping by several groundwater users in the area (the City, NPC, and private agricultural wells) contributed to the distribution and movement of COCs within the Intermediate Aquifer, particularly movement away from the WWTP. In 2004, VC was detected in newly installed wells (M-30C1, M-30C2, and M- 31 C1) southeast of the WWTP. As of April 2009, VC was detected at wells M- 17C1, M-20C1, and M-20D north of the WWTP. VC is present at levels ranging from below laboratory reporting limits to 180 pg/L in these wells. TCE concentrations in Intermediate and Lower Aquifer monitoring wells near the WWTP ranged from below laboratory reporting limits to 80 pg/L. The cis-1,2- DCE concentrations in these wells range from below laboratory reporting limits to 260 pg/L. The presence of cis-1,2-DCE and VC is an indication that conditions 15