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0 <br /> A S S O C I A T E S I N C <br /> Installation Of Groundwater Extraction System <br /> ' The groundwater extraction system consisting of the groundwater treatment unit and associated <br /> piping was installed between January and March 2002 <br /> ' A 1-inch diameter, schedule 40 PVC process piping and 314-inch diameter, schedule 80 PVC <br /> electrical piping conduit were installed in the on-site trench at approximately 8 inches bgs A <br /> manifold PVC piping system was utilized in the trench to connect the process piping system <br /> from each extraction wellhead to the groundwater treatment system Four-inch diameter, <br /> stainless steel model 5S 10 Grundfos Rediflow down-well pumps equipped with 230 volt <br /> Franklin 112-horsepower 3-wire motors were installed in groundwater extraction wells EW-1, <br /> EW-2, EW-3, and VW-6 The Grundfos pumps were installed in each well at a depth of <br /> approximately 30 feet bgs Electrical PumpTec controller boxes were installed in the electrical <br /> control panel for individual control measures of extraction well pumps Pump controls were <br /> supplied by an amperage sensing/time control switch This switch would detect any decrease <br /> in amperage when water level drops below the impeller intake from any of the Grundfos <br /> ' pumps <br /> Three 2,000-gallon media vessels, one 1,000-gallon poly holding tank, one process pump and <br /> one sediment filter chamber were installed for the groundwater treatment system Groundwater <br /> pumped from the recovery wells was initially routed via the piping system to the 1,000-gallon <br /> holding tank prior to processing The process pump was designed to process groundwater <br /> ' through the treatment system at a maximum flowrate of 20 gallons per minute (GPM) The <br /> groundwater was routed to the three 2,000-pound vessels containing GAC The GAC media <br /> vessels are designed to adsorb TPHg and BTEX compounds Brass sampling ports were <br /> ' installed at the influent, between the media vessels and at the effluent to allow detection of <br /> potential media break through and to obtain final discharge samples Ari F-2000 model RT <br /> Blue-White Industries flow meter was installed on the effluent line to continuously measure <br /> ' and display the effluent flowrate and to continuously measure and display the total flow <br /> ' The groundwater treatment system was designed to operate at a maximum flowrate of up to 15 <br /> GPM, therefore each of the three recovery wells was adjusted to extract groundwater at a <br /> flowrate of approximately 5 to 6 GPM by extracting on an intermitting cycle The operation of <br /> the pumps allow for up to a four-minute hiatus interval after which the pump will reactivate <br /> This hiatus mainly allows for water level recharge within the wells The groundwater <br /> treatment system operates on a batch basis, with a daily total of 14,400 gallons Once the <br /> ' 2,000-gallon holding tank filled, approximately 1,750 gallons of extracted groundwater was <br /> treated and discharged The discharge of treated water (effluent) to the City of Stockton was <br /> adjusted at a flow-rate of approximately 115 GPM <br /> ' Grab groundwater samples were collected from the influent of each well and the effluent of the <br /> treatment system Samples were collected to laboratory-supplied 40-m1 EPA-approved volatile <br /> organic analysis (VOA) vials containing 0 5 ml 18% hydrochloric acid as a preservative <br /> w 1271421reportslc1osure doc 10 <br /> I <br />