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16 August 2011 AGE-NC Project No , 97-0301 Page 9 of 11 each well-head location so that dual phase water and/or soil-vapors can be adjusted , drawn from each well independently or drawn from a combination of specific wells . An individual sample port with check-valve to prevent back-flow cross contamination will be installed at the process piping riser at the wells. These sampling ports will allow sampling of wells independently without having to remove the well head assembly. Following piping placement, the trench will be backfilled with imported road-base sand , compacted and resurfaced with concrete or asphalt. 3.4 . DUAL PHASE VAPOR EXTRACTION SYSTEM DESIGN The dual phase extraction remediation system will consist of a 20-horsepower, liquid-ring pump to simultaneously extract soil-vapor, ground waterand adsorbed NAPL from the two proposed DPE wells (4-inch diameter wells screened 10 to 40Jeet bsg), wells VW- 1 through VW-3 (4-inch diameter wells screened 10 to 30 feet bsg ) and from well MW-7 (2- inch well screened 20 to 40 feet bsg ;the vacuum pump under standard temperature and pressure was capable of producing a maximum vacuum of 28-inches Mercury (Hg ) with a nominal capacity of 300 cubic feet per minute (CFM ) . DPE will be accomplished by installing a 1 -inch diameter PVC , flexible and reinforced "stinger" tube from the top of the wells to a depth of approximately 2 to 3 feet from the base of the wells; at the well-head , an air-tight seal will be formed between the 1 -inch diameter PVC tube and the 2-and 4-inch diameter wells head utilizing a well-head assembly. The stinger will allow the extraction of soil vapor within a depressed water table , caused by the rapid extraction of water from within the well screen . From the well-head , 1 -inch diameter PVC piping will used underground to connect to the liquid ring vacuum pump . From the liquid ring pump , dual phase extraction will be routed into a water-vapor separating chamber. From the separating chamber, the ground water will be processed (via process pump) directly through three (3) 2 ,000-pound media vessels containing liquid phase activated carbon ; simultaneously soil-vapor will be processed through a secondary water knock-out pod , then processed through a electric heated catalytic oxidizer. Processed groundwater will be discharged under City of Stockton permit into the sanitary sewer system ; processed vapor will be destroyed by catalytic oxidation and the byproducts exhausted into the atmosphere under San Joaquin County Air Pollution Control District permit. A basic diagram of a typical system is illustrated in Figure 5 . Additional information on the proposed system is included with Appendix B . 3 .4 . 1 . DPE-Soil Vapor Extraction Monitoring During the "start-up" period for the DPE system , organic vapor samples will be collected and operational parameters will be monitored on a daily basis . The anticipated start-up I Advanced CeoEnvironmental, Inc.