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Corrective Action Plan Page 29 Following the commissioning period, the rate of water flow through the groundwater treatment system and the concentration of total petroleum hydrocarbons (TPH) in the influent stream to the air stripper will be regularly monitored (The water-quality sampling schedule is discussed in a later section of this document) Those measurements will be used to estimate the resultant discharge of VOCs to the air In making the calculations it will be conservatively assumed that all VOCs in the water can be transferred to the air If the estimated discharge to the air, as computed from the condition of the water influent to the air stripper, is within 5% of the permissible limit of 2 lb per day, the actual VOC concentration in the air-stripper exhaust will be directly measured using an OVM If the result of this test shows that the actual rate of emission of VOCs is within 5% of the permissible hmit, the air stripper influent water and exhaust air will be analyzed weekly for a minimum period of one month If necessary, emissions to the air will be restricted by temporarily reducing the rate of groundwater pumping or by-passing the air stripper until the high contaminant-load excursion has passed It is not expected that there will be any actual need to implement these contingency measures, but the capability to operate the treatment system in the described manner ensures that emissions to the air will be maintained within permissible limits under any foreseeable condition Process Flew zni3 Cont A schematic process and instrumentation diagram for the proposed groundwater recovery and treatment system is presented as Figure 11 The process equipment and instrumentation identified on the diagram are described on Figure 12 Groundwater Pumps. Water is pumped from the recovery wells (RW-1, RW-2 and RW-3) by self-priming, submersible pumps (P-1) These pumps have modular, 1/2 horse power motors, are constructed from stainless steel and have Teflon seals that will not degrade in the presence of water affected by hydrocarbons Water levels in the wells are regulated by radio-frequency admittance type, differential water-level probes (LS-1) and pump controllers (LC-1) The probes and controllers are calibrated so that the pumps are energized when water levels in the wells are between 5 ft and 18 ft beneath the ground surface If the water level in any well drops below 18 ft , the pump in that well is de-energized so that the pump motors remain submerged under at least 2 ft of water at all times At that point, the water level begins to rise in the well and the pump is re-energized when the level reaches 12 ft beneath the ground surface (approximately 5 ft beneath the static water table) has been previously described, when groundwater is pumped from the wells a cone of � As p y depression is formed in the water table The sustainable rate at which water can be pumped from the wells will change as the cone of depression expands (generally the sustainable pumping rate will fall with the passage of time) The pumping rate required to maintain an essentially constant drawdown of the water level in the wells is also influenced