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5.3 System Operation and Optimization Prior to the onset of groundwater extraction,water level measurements will be collected from all wells within the zone of capture (approximately 127 feet) of the extraction wells. Once the interim system is installed and operating,ERG will conduct weekly monitoring of the system and well performance including measurement of extraction rates, system inlet concentrations,totalizer readings, as well as individual well measurements for groundwater drawdown. This monitoring will allow us to measure system performance, obtain valuable design data, and quantify the amount of hydrocarbon mass removed from the Site. Groundwater elevations will be monitored in all nearby wells to determine the extent of subsurface influence. Wells MW-2 and MW-10 will be monitored closely to determine if there is a need to bring these wells online. 5.4 Groundwater Disposal The pump test data indicates that a large quantity of groundwater will be produced by the interim action. ERG anticipates that each well could yield approximately 7,200 ka gallons of water during a 24-hour period. It is our intent to store the extracted groundwater in a5,000 gallon water storage tank,treat the extracted groundwater using liquid phase carbon, and discharge the treated water to the nenrhv qtnrm timin N P 0 6 We intend to obtain a permit from e qty of Lathrop for the discharge. The City of P'MJ+ Lathrop has been contacted and additional data needs have been identified. The additional data will be collected during the 4h Quarter Groundwater sampling event. If discharge of the treated water is granted,ERG will install a groundwater treatment system equipped with two 1,000-pound carbon vessels. In the event that permitting of the treated water and discharge to the storm drain is not granted by the City of Lathrop, an alternative approach for groundwater disposal may be used. This alternative approach will involve reducing the number of groundwater extraction wells and storing the extracted water on Site in a 20,000-gallon storage tank. Groundwater will be removed from the site each day by a vacuum truck and transported offsite for disposal. Water will be transported from the wells by above- H o se 4 ground flex to the storage tank. The tank will be equipped with high leve-�_ 1 shy o alarms to revent overflow. The nearest storm drain is located in the southeast corner of the site near the ASTs. 54-r,,+v.5 ERG plans to place the storage tank on the north.side of the building and run above- �1 10 pa' 5 ade_nining within the planter_that runs north/south on the east side of the property. --vq The piping will be double contained to prevent any leaks to the planter. ,O��a�w 6.0 REPORTING Ma Y ERG will prepare monthly progress reports outlining the field data collected during the interim remedial activities. The reports will include water level measurements, volume of groundwater extracted during the period, mass removed, extraction rates, and ERG,0406 Page 5 IRAP