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'- Geo(pgfcal rech4(a inc. Page 6 Interim Remedial Action Plan Project No.622.2 March 28,2005 final system will not be known until treatment system manufacturers bids are received and evaluated. The following parameters/requirements will be provided to manufacturers upon which to base their system designs: Antici ated va or flow rates: 300 scfm (standard cubic feet minute) maximum, expect 50 - `� 100 cfm. Rationale - maximum flow during the pilot test was 108 cfm. Anticipated va or concentrations: 0.027 mg/l TPH-G, 0A19 mg/l MTBE. Rationale—average laboratory value from pilot test well EW-2 data. Anticipated groundwater flow rates: maximum 10 gpm Rationale —the pumping rate from the two existing extraction wells ranged from I to 11 gpm during the pilot test. GTI believes that a rate of 10 gpm could have been sustained throughout the remainder of the test if we had the capacity to store the water. As previously reported we had to reduce pumping rates to preclude the holding tank from overflowing. Anticipated groundwater concentrations: maximum of 4400 ug/l TPH-G & 3600 ug/1 MTBE influent to the carbon treatment system. Rationale - a maximum of 2200 ug/7 TPH-G & 1800 ug/7 MTBE were recorded from the ` effluent port after the vapor/water separator during the pilot test. The water from extraction well EW-1 had a maximum of 210 TPH-G &230 ug/7 MTBE. The TPH-G and MTBE values then represents the maximum concentrations with a safety factor(2:1) added to ensure sewer discharge requirements are not exceeded. It is noted that higher concentrations of TPH-G & MTBE are present in groundwater beneath the UST excavation but the liquid ring process causes a water to vapor phase transfer. The water effluent will then have lower contaminant concentrations as it exits the liquid ring chamber. Carbon adsorption capacity is a function of the carbon properties (density, surface area, etc.), contaminant concentration & chemical properties, general mineral chemistry of the water, temperature and contact time. These parameters are studied under laboratory conditions and then confirmed through field-testing to allow carbon manufacturers to produce isotherms for their units. GTI will request a carbon vessel contractor to develop an iso-therm for the subject site. They will then determine an applicable design usage rate in lbs/day to size the system based on the above soil vapor extraction rates and contaminant concentrations. The carbon system will also be subject to the USTCFP's three bid process. 3.1.3 System Control & Monitoring GTI will perform monitoring of the system to obtain maximum contaminant removal efficiency and compliance with regulatory permits. This will include: 4 V