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7 03 September 2004 AGE-NC Project No 98-0448 ' Page 7of13 ' 32 IN-SITU AIR SPARGING SYSTEM PROCEDURES The IAS system utilized a 5 horsepower, Speedarre (model no 5F229B) electric air compressor to inject air beneath the water table From the outlet of the air compressor, a manifold network of one- inch diameter, schedule 80 PVC piping was installed underground to the well heads at IAS wells AW-1 through AW-4(screened 25 to 30 feet),IAS well AW-5(screened 30 to 35 feet)and IAS well ' MW-4B(screened 45 to 50 feet) A Wilkerson oil filter(model no M 18)and Wilkerson air pressure regulator (model no R28) are installed at the outlet of the air compressor for added controls, Wilkerson air pressure regulators (model no R 18) are installed at each IAS well-head to enable ' independent control over the varying pressures required,at each well,to eject the water from the welI casing and resulting continuous air sparging at all of the above referenced well heads in the IAS network system The injected air should mechanically strip adsorbed hydrocarbons and/or volatilize ' dissolved hydrocarbons in ground water, and force hydrocarbon vapors into the vadose zone,where they can be withdrawn by the SVE system ' Generally,air pressure was discharged at shallow screened IAS wells AW-1 through AW-5 between 5 and 8 pounds per square inch (psi), and to deeper screened well MW-4B between,13 and 15 psi A liquid-filled, air-guage was installed at each of the above well heads to monitor air pressure I33 SOIL VAPOR EXTRACTION/IN-SITU AIR SPARGE REMEDIATION FINDINGS From field data collected at the SVE remediation system between 28 January and 22 June 2004, I AGE determined the average TPH-g concentration and the average flow rate and calculated the approximate mass and volume of hydrocarbons removed 3 3 1 RESULTS OF VAPOR EXTRACTION Between 28 January 2004 and 10 March 2004,and between 20 April and 22 June 2004,the SVE and IAS remediation systems were continuously operational for 2,520 hours (105 days), SVE/IAS _ remediation operations were temporanly suspended between 10 March and 20 April 2004`forrepairs To date, the SVE and IAS remediation systems have totaled 26,224 hours of operation since initiation on 16 April 2001 (Table 4) During the above operational period,SVE inlet flow rates were recorded between 20 and 70 cubic feet per minute (cfim), differential pressures were recorded between 0 15 and,1 8 inches of water Induced vacuum measurements ranged between 34 and 72 inches of water Utilizing an OVA, SVE inlet hydrocarbon concentrations were measured between I2 9 and 347 parts per million (ppm) Field measurements are summarized in Table 3 Advanced GeoEnvironmental,Inc w I `