ARCHIVED REPORTS XR0003542 - Laserfiche WebLink

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r + CAMBRIA SYSTEM DESCRIPTION The GWE system currently consists of one pneumatic submersible pump installed in well RW-1A, a transfer tank, transfer pump,flow totalizer meter, filter vessel, and three 1,200-1b aqueous-phase, granular activated carbon(GAC)vessels Groundwater is pumped from the well into the transfer tank When the tank is full,level switches activate the transfer pump, which pumps water through the filter vessels The three carbon vessels are connected in series A flow totalizer located downstream of the carbon vessels records the volume of water being discharged into the City of Stockton sewer system The discharge is authorized under a City of Stockton wastewater discharge permit, issued on October 23, 2000 SYSTEM OPERATION The GWE system was started on May 31,2001 for the purpose of collecting start-up(grab)samples The system was shutdown after sample collection All permit-specified pollutants were reported below the discharge limits Start-up sample analytical results were submitted to the City of Stockton on June 18, 2001 . Continuous operation of the GWE system began on June 20,2001 For the current reporting period, monthly(grab) samples were collected from the influent of the first, second,and third carbon vessels and the effluent of the third carbon vessel, prior to discharge into the sanitary sewer The samples were analyzed for TPHg, benzene, toluene, ethylbenzene, and xylenes (BTEX), and MTBE by EPA Method 8260B Sena-annual trace metal analysis(Cadmium,Chromium,Copper,Lead,Nickel and Zinc)was performed on system effluent samples collected May 22,2002 All permit-specified trace metals were analyzed by EPA 200 Series Method,and were reported below the discharge limits Analytical results for the GWE system sampling are summarized in Table 1 and presented in Appendix A As of May 22, 2002, the GWE system has extracted and treated an estimated 679,780 gallons of groundwater, removing approximately 277, 44 5, and 448 lbs of TPHg, benzene, and MTBE, respectively Extraction totals are summarized in Table 2 Spent carbon from the GAC vessels has been replaced with virgin coconut carbon three times since the GWE system began operating The carbon from all three GAC vessels was replaced on November 11, 2001,February 12, 2002 and April 17, 2002 On February 12, 2002, one of the GAC vessels itself,which had a leak in it, was also replaced 0783 2