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J 28 June 2001 AGE-NC Project No. 95-0103 Page 4 of 9 down-well pumps, equipped with Franklin %4 hp, 110V, 3-wire motor will be installed in the ground water monitoring wells. One-inch diameter Schedule 40 PVC pipe will be installed from the pump discharge to the surface with a safety chain to prevent dropping the pump to the well bottom. This well system is rated to remove up to five gallons of water per minute (gpm). To minimize sediment intake through the pump, the bottom of the pump/motor assembly will be suspended approximately 2 feet from the extraction well bottom. Electrical wiring will be connected from the top of the pump through Class I electrical connectors/junction boxes and electrical conduit to the pump controller. 3.5. WELL AND PROCESS PUMP CONTROLLERS Both the extraction well pumps and the water treatment process pumps will be controlled by PumpTec controllers;the ground water extraction pumps will operate on an independent controller. The pump control will be supplied by an amperage sensing/time control switch. This switch will detect a decrease of amperage when water level drops below the impeller intake of the Grundfos PUMPS. The process pump, located downstream of the holding tank,will be controlled by electrode switches placed at various levels in the holding tank. An emergency shut-off switch will be located immediately below the top of the holding tank. An intermediate pump-on switch will be placed approximately 8 inches below the emergency shut-off switch and to activate the process pump. Intermediate pump-off switches will be utilized near the bottom of the holding tank to turn the process pump off. 3.6. TREATMENT SYSTEM AGE proposes the use two 2,000-pound granular activated carbon(GAC)absorption vessels in line to treat extracted ground water. Prior to processing, one 750-gallon poly tank will be used to temporarily store extracted water. This tank is equipped with upper and lower level control switches that serve to control the rate at which extracted water is introduced into the GAC, to provide safety shutoff capabilities, and to allow coarse sediment to settle out prior to treatment. The process pump is located after the holding tank. The system will be enclosed within a fenced area to allow for security(Figure 3). The treatment media is contained in a set of 2,000-pound GAC absorption vessels. The GAC vessels are designed to adsorb TPH-g, and BTEX compounds and to adsorb MTBE. Sample ports are located between the raw water process holding tank and each carbon-vessel to allow raw water sampling for analysis, to detect the process break through concentrations and to obtain final discharge samples.