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Final Remedial Plan - Geweke <br />' 2 January 1992 <br /> Page 14 of 15 <br />' The treated water is proposed to be discharged back into the <br /> aquifer through one of the up-gradient wells. A waste discharge <br /> permit application to the Central Valley RWQCB is currently being <br />' prepared. <br /> A schematic representation of the extraction, treatment and <br />' discharge system is shown in Figure 6. Specifications of the Clean <br /> Environment pump and parts of the system are attached. <br />' 4 . 3 . EXTRACTION FLOW RATE <br />' Based on the relatively hydraulic conductivity expected from the <br /> aquifer material consisting of (silty) fine to medium sand, an <br /> average extraction rate of approximately 1. 0 gallon per minute will <br /> be maintained to create a steady radial flow to the well . This flow <br />' rate converts to a volume between 6, 000 and 10, 000 gallons of <br /> recovered fluid per operational week. <br /> 4 . 4 . CONFIRMATORY SAMPLING PRIOR TO DISCHARGE <br /> Confirmatory water samples will be obtained for every 4 , 000 gallon <br /> treatment batch to document the successful removal of contaminants. <br /> These samples will, be analyzed for total petroleum hydrocarbons <br /> (TPH) in accordance with an approved DHS method for gasoline and <br /> for purgeable aromatic hydrocarbons (BTE&X) in accordance with EPA <br /> method 8020 . The treated water will be discharged only after the <br /> TPH level for each batch equals or falls below the clean up level <br />' of 1. 0 mg/l for TPH and the California Drinking Water Standard <br /> (DWS) for BTE&X established by the DHS/RWQCB. The analytical <br /> results will be documented and submitted to the RWQCB and the SJEHD <br /> ' after the completion of the project. <br /> 4 .5 . OPERATION <br /> After the removal of approximately 4 , 000 gallons, the system will <br /> be shutoff for a period of 48 to 72 hours to allow the aquifer to <br /> recover. This process will allow an effective flushing of ry� <br /> contaminants from the aquifer materials. The plan calls for MW-4 to <br /> be used as the main extraction well. In order to capture off-site <br /> contaminants, additional wells, such as EW-1 and MW-3 may be used. <br />:b If necessary, the water extraction/treatment program is performed <br /> in several phases. After treatment of approximately 20, 000 gallons, <br /> ' aqueous samples will be obtained from the extraction well (MW-4) <br />