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Nestle USA, Inc., Ripon, California March 31, 2011 <br /> 2010 Annual Report <br /> • ECM installed a GAC treatment system at 802 Vera Avenue in Ripon on September 27, <br /> 2010, following the discovery of CDCs in the well located at this address. <br /> • On January 14 and 15, 2010, Boart Longyear completed a second well development in <br /> the replacement well at 5725 Hall Road to improve the well performance. Amerine <br /> Systems, Inc. (Amerine) completed installing the pump in the replacement well and <br /> plumbing the well to the treatment system on March 17, 201 027. Responding to the <br /> presence of arsenic in the water produced by the well, a series of tests were conducted <br /> in July 2010 to determine the most suitable depth to place the well pump to maintain the <br /> arsenic concentration below the MCL. <br /> 4.3.2 PERFORMANCE MONITORING <br /> ECM collected and analyzed the influent, mid-point, and effluent samples from the three private <br /> treatment systems twice per month. System samples were analyzed for VOCs bi-monthly and <br /> for nitrates once a month, per the MRP (Table 9.2). The following is a summary of the private <br /> well treatment system performance data and a discussion of the results of the performance <br /> monitoring. <br /> • No VOCs have been detected at laboratory reporting limits in effluent water at any <br /> location. The private treatment systems removed 100% of the VOCs in well water <br /> effluent (Table 9.2). <br /> • Influent TCE and cis-1,2-DCE concentrations at the 802 Vera Avenue wellhead treatment <br /> system ranged from 2.2 pg/L to 5.5 pg/L and 6.3 pg/L to 12 pg/L, respectively. No VC <br /> concentrations above the laboratory reporting limit were detected in samples from the 802 <br /> Vera Avenue well. COC concentrations in the well at 802 Vera Avenue have declined <br /> since the treatment system was installed, as illustrated in the following figure. <br /> 802 Vera Avenue Concentrations over Time <br /> 16 <br /> e <br /> 14 <br /> 12 ° <br /> J <br /> 10 ° <br /> y <br /> w0 8 <br /> O <br /> L e <br /> = 6 <br /> � e <br /> V <br /> = e <br /> O 4 e <br /> U ° <br /> e <br /> 2 ° <br /> 0 C 4 G <br /> Jul-10 Aug-10 Sep-10 Oct-10 Nov-10 Dec-10 Jan-11 Feb-11 <br /> A TCE e CIS o VC TCE Trendline cis-1,2-DCE Trendline <br /> 25 <br />