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I26 February 2001 <br /> AGE-NC Project No 95-0173 <br /> Page 3 of 8 <br />' EHD by letter dated 20 April 1999 <br /> 3 1 SOIL VAPOR EXTRACTION/IN-SITU AIR SPARGE SYSTEM PROCEDURES <br /> Between 01 October 2000 and 31 December 2000, the SVE and IAS remediation systems were <br />' operational at the site The SVE system utilized a Solleco Ecat 250 catalytic converter vapor <br /> extraction system The SVE system consisted of two-inch diameter, schedule 40 PVC piping <br /> installed underground fiom each well-head at wells VW-1,VW-2, VW-3, VW-4, VW-5, VW-6 and <br />' VW-7 and connected to the Inlet of the Solleco Ecat 250 vacuum blower,the outlet from the vacuum <br /> blower was routed through the catalytic converter Induced vacuum was measured utilizing a <br /> Magnehelic vacuum gauge attached to the inlet of the blower, air flow was monitored using a Dwyer <br />' DS-200 flow sensor The flow rate was determined from the measured differential pressure and the <br /> piping diameter using a nomograph(Appendix B) The vapor stream at the SVE inlet was monitored <br /> routinely for the presence of organic vapor using an organic vapor analyzer(OVA) equipped with <br />' a photo-ionization detector(PID Thermo Environmental 580A, 10 0 eV, calibrated to isobutylene) <br /> Sampling ports were installed upstream of the vacuum blower inlet to recover influent soil-gas vapor <br /> • stream samples, and downstream of the catalytic converter to recover effluent stream samples to <br />' monitor the efficiency of hydrocarbon destruction Field measurements were recorded at regular <br /> Intervals throughout the pilot test and are summarized In Table 5 <br />' <br /> 32 COLLECTION AND ANALYSIS OF SOIL GAS SAMPLES <br />' A total of three pairs of extracted soil-gas vapor samples were collected from the inlet and outlet of <br /> the regenerative vacuum blower unit to measure concentrations of hydrocarbon vapor The samples <br />' were collected in Tedlar bags using a hand air-vacuum pump <br /> Following sample collection, the samples were placed in a covered container and transported under <br />' chain-of-custody to McCampbell Analytical Laboratory (MAL)in Pacheco,California Each sample <br /> was analyzed within 72 hours of collection for TPH-g and BTEX in accordance with EPA Methods <br /> 5030/8015 Modified and 8020 <br /> 4.0. FINDINGS <br /> Ground water elevation, flow direction and gradient were determined from field data collected on <br /> 21 December 2000, the contaminant impact to ground water was assessed from the ground water <br /> laboratory data <br /> • Advanced GeoiJnvironmental,Inc <br />