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down the GETS if a high level is detected The oil-water separator and the temporary <br /> product storage tank are vented through a 55-gallon drum containing 200 lb of activated <br /> carbon. <br /> Water containing dissolved hydrocarbons is transferred by gravity from the oil-water <br />' separator to a holding tank. Just prior to the holding tank, the rate of flow and the volume of <br /> water is measured by totalizing flow meters. The holding tank has both high and low level <br /> switches. If a high or k, the entire GETS is �hut <br /> down. From the holding tank, water is transferred at a constant rate of 50 gpm to the top of <br /> the air stripper by a pump Between the pump and the air stripper the water is filtered by a <br /> panicle filter and the now is controlled by a flow control valve. A portion of the water from <br /> the air stripper is cycled back to the holding tank and the remainder(equivalent to the amount <br /> that enters the treatment system) flows into another tank by gravity. A check valve in the <br /> recycle line prevents water from bypassing the air stepper. Transfer pumps are protected by <br /> both a high pressure switch and a minimum flow restrictive orifice. <br /> As a contingency, a metering pump may be used to inject either acid or a sequestering agent <br /> into the water prior to entering the air stripper, if needed(to remove scale and any biological <br />' growth) <br /> A vacuum blower is used to induce air flow through the air stripper. Air, moisture, and <br /> hydrocarbons pass from the air stripper through a moisture separator and a manual butterfly <br /> control valve upstream of the blower. Downstream of the blower, vapor passes through a <br /> flow switch, a flow meter, a motor-actuated butterfly shutoff valve, a spring-loaded check <br />' valve, a manual butterfly valve, and then into a catalytic oxidizer. Differential pressure is <br /> measured across the air stripper packing to monitor any changes in the resistance of now due <br /> to packing fouling A pressure switch located upstream of the moisture separator will shut <br /> down the GETS if insufficient vacuum is detected In the event the GETS shuts down, both <br /> a spring-loaded check valve and a motor-actuated butterfly valve will isolate the GETS from <br /> the vapor extraction and treatment system (VETS), allowing the VETS to continue operation. <br /> A combination of a flow meter and a manually-operated butterfly valve will be used to adjust <br /> the flow of air through the air stripper. As a backup to the pressure switch, a flow switch <br /> will detect any back flow from the VETS to the air stripper, if backflow is detected, the <br /> GETS is shut down, and the motor-actuated butterfly valve isolates the two systems <br /> Water passing through the elevated section of piping between the air stripper and the holding <br /> tank flows by gravity into the tank A differential level switch is used to turn the transfer <br /> pump on and off and to maintain the level in the holding tank between high and low set <br /> points. A backup high level switch will shut down the GETS if a high level is detected to the <br /> holding tank A transfer pump pumps water from the second holding tank through a particle <br /> filter, pressure reducing valve, and two activated carbon adsorbers in series. The pump is <br /> protected by a minimum flow restrictive orifice <br /> ,.avn9ar�.,w,n 3 <br />