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Groundwater Gradient: 0.003 ftlf# SVE SYSTEM QUARTERLY OPERATION AND PERFORMANCE Equipment Inventory: _ Solleco 100 cfm electric catalytic oxidizer Operating Mode: ^ Catalytic APCD Permit No.: N-4887-2-0 Influent TPHG Concentration End of Period: 310 milligrams per cubic meter(mg/m) Influent Benzene Concentration End of Period: X0.15 m /m3 Flow Rate End of Period: 97 HC Destroyed this Period(lab): 15.32 lbs as TPHG Cumulative HC Destroyed: 4,110.46 lbs as TPHG Percent Time Operational: System operating in pulse mode DISCUSSION: At the time of the fourth quarter 2005 monitoring event, groundwater elevations had increased between 0.42 and 1.31 feet in all wells since the previous monitoring event (July 26, 2005). Depth-to-water measurements were normalized to mean sea level (MSL), and were used to construct a groundwater elevation contour map (Figure 2). Well S-1 was dry. The groundwater flow direction was generally to the south-southeast at an average gradient of 0.003 ft/ft. A south-southeast groundwater flow direction has consistently been observed during previous monitoring events. TPHG (71 tcg/L) was reported in well MW-3. BTEX, MTBE, TBA, DIPE, ETBE, TAME, methanol, or ethanol were not reported in any of the wells. Analytical results are generally consistent with historical analytical data. TPHG, benzene, and MTBE data have been summarized on Figure 3. System Description Soil Vapor Extraction and Abatement (SVE)System The SVE system consists of a Solleco 100 cfm electric catalytic oxidizer (Model 100 ECAT) with a 5 horsepower (hp) blower. Upon start-up of the current remediation system (October 20, 2004), petroleum hydrocarbon laden soil vapors were extracted from wells VW-1, S-1, S-2, and MW-8 using the 5 hp blower package of the SVE system rated at 100 cfm at 14 inches of mercury. Figure 2 presents the locations of the vapor extraction wells, remediation system, and other pertinent site features. The extracted soil vapors were abated in the catalytic oxidizer prior to discharge to the atmosphere. The SVE system has an in-built hour meter and recordings are used to determine the operational uptime. Sample ports (influent, cat-influent, and effluent) are designated to collect air samples. The results of air samples are used to estimate the destruction efficiency of the system. Remedial activities at the site were initiated with a SVE system consisting of a 150 cfm Stealth Bobcat catalytic oxidizer (cat-ox) and was operated at the site between August 15, 2000 and August 15, 2002, under permit N-903-2-0. Due to low influent concentrations, the cat-ox system was replaced with a SVE system consisting of a 2.3 hp Fuji Blower and two 1,000 lbs vapor phase carbon units, which operated at the site between August 1, 2003 and March 12, 2004, under permit N-4887-1-0. The vapor phase carbon adsorption system was replaced with the currently operating Solleco 100 cfm electric cat-ox in October 2004. The 150 cfm Stealth Bobcat SVE system operated at the site for a total of 13,624 hours and removed approximately 3,467 pounds of TPHG and the carbon adsorption system has operated at the site for a total of 2,124 hours and removed approximately 33.53 pounds of TPHG. K:IUSA Gasolinc100651Qtrly120051USA_65_4Q05.DOC 5r1zArU5