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• <br /> The following procedures will be followed for the well <br /> installation: <br /> o General procedures as covered earlier will be followed. <br /> o The location for the well will be sampled with a hand auger <br /> to an 8 foot depth. The samples will be visually inspected to <br /> ensure the location does not contain perched oil or water or <br /> another condition that might hinder the test. <br /> o A 6-inch diameter borehole will be advanced to 16 feet <br /> using hollow stem auger or similar drilling techniques. <br /> o A 10-foot long capped and threaded screen of appropriate <br /> slot size will be placed in the bottom of the borehole. <br /> o Unslotted schedule 40 PVC pipe will be installed from the <br /> top of the screen to 1.5 feet below grade. <br /> o A gravel pack consisting of the appropriate sand or gravel <br /> will be placed in the borehole annulus to the top of the well <br /> screen. <br /> o A 4 foot bentonite/cement seal will be placed above the <br /> gravel pack to 2 feet below grade. <br /> o A 2 foot deep vault box (with a locking lid) will be placed <br /> over the bentonite seal and flush with the ground surface. <br /> Note: Dimensions given above may change slightly in <br /> final design. <br /> Vapor Line <br /> At the top of the well a 2 inch PVC pipe will connect the well to a <br /> liquid ring vacuum pump followed by activated carbon treatment of <br /> the vent gas (for odor control) . The process flow diagram on Plate <br /> 5 shows the system configuration. An air bleed inlet will take in <br /> additional air to meet the pump' s capacity demands. Appropriate <br /> ports and equipment for gas sampling, flow measurement and vacuum <br /> monitoring will be installed in the line. <br /> Pump <br /> A liquid ring vacuum pump will be used to pull air through the <br /> ground and well and discharge it through carbon treatment to the <br /> atmosphere. The pump has no contacting metal parts on the process <br /> side as it uses circulating water to seal. The liquid seal makes <br /> the pump run quietly and provides added safety if explosive <br /> concentrations of hydrocarbon are in the vent gas. Explosive <br /> concentrations (>14 , 000 ppm) , however, are unlikely to occur at <br /> Tracy (estimate 300 ppm in vent gas) . The pump 's driver will use <br /> electrical power supplied from an appropriate connection with PG&E. <br /> The water will be supplied to the pump from a nearby water main and <br /> 4 <br />