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Interim Groundwater Treatment System Operation, Maintenance, and Monitoriniz Manual 1.0 GENERAL DESCRIPTION The interim remedial action will consist of groundwater extraction, treatment, and discharge to the ground surface. The system will consist of three major components: 1) extraction well, 2) a conveyance system to and from the treatment area, and 3) a treatment system. Extraction Well Initially, it is proposed to utilize existing well MWI as the single extraction well, based upon its location at the source of contamination (former USTs). Pumping from this location may establish hydraulic control over the most contaminated portion of the phone. Based on a review of well purge logs, we estimate that well MWI will be able to sustain a pumping rate of between 1 and 2 gallons per minute (gpm). Additional extraction wells may be installed if necessary, based upon continued monitoring and evaluation of interim remediation actions. ConveyanceSystem Contaminated groundwater will be pumped from well MWI through subgrade piping to the treatment system. Conveyance piping will be double-contained, consisting of buried 4" diameter, schedule 40 PVC with internal flexible tubing. Backflow prevention will be incorporated into the system. Treatment Sim Extraction system controls and the carbon units are located in a fenced compound in the southeast portion of the parking lot (Figure 2). Extracted groundwater will be processed via sub- grade, PVC piping through two 2,000-pound granular activated carbon (GAC) units, which will be configured in series. The treatment system is fitted with a manifold constructed of PVC piping, which allows configuration of either GAC unit as the primary unit. Sample ports are located between all vessels to allow detection of potential contaminant break through and to obtain samples immediately prior to discharge. The GRUNDFOS submersible pump is controlled by Warwick high and low float switches and a Warwick 16 amp circuit breaker. A general schematic diagram of the GAC interim groundwater treatment system is shown on Figure 3. Treated effluent will be discharged to the ground surface via surface sprinkler(s). The discharge area is located in the adjacent undeveloped field, which is approximately 3-4 feet lower in elevation than the surrounding surface roads and developed pad. No run-off is expected from the discharge area. The GAC units will be changed out as needed, based upon results of influent and effluent samples collected from the primary and secondary units. Once breakthrough occurs in the primary unit, the roek%o&mmanl Page 1