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02 November 2001 <br /> AGE-NC Project No 95-0173 <br /> Page 3 of 8 <br /> system, during this time, IAS remediation was continued at the site by air sparging at wells MW-1, <br /> MW-2, MW-3, AW-1, AW-2, AW-3, AW-4, AW-5, AW-6 and AW-7 SVE and IAS procedures <br /> for the site were described in Remedial Action Work Plan dated 30 December 1998, prepared by <br /> AGE, and approved by the PHS-EHD by letter dated 20 April 1999 <br /> 31 SOIL VAPOR EXTRACTION/IN-SITU AIR SPARGE SYSTEM PROCEDURES <br /> Between 01 April 2001 and 30 rune 2001, the SVE and IAS remediation systems were operational <br /> at the site The SVE system utilized a Solleco Ecat 250 catalytic converter vapor extraction system <br /> The SVE system consisted of two-inch diameter, schedule 40 PVC piping installed underground <br /> from each well-head at wells VW-1, VW-2, VW-3, VW-4, VW-5, VW-6 and VW-7 and connected <br /> to the inlet of the Solleco Ecat 250 vacuum blower, the outlet from the vacuum blower was routed <br /> through the catalytic converter Induced vacuum was measured utilizing a Magnehelic vacuum gauge <br /> attached to the inlet of the blower, SVE air flow was monitored using a Dwyer DS-200 flow sensor <br /> The flow rate was determined from the measured differential pressure and the piping diameter using <br /> a nomograph (Appendix B) The SVE air flow rate along the influent and effluent-lines was <br /> monitored routinely for the presence of organic vapor using an organic vapor analyzer (OVA) <br /> 1 • equipped with a photo-ionization detector(PID Thermo Environmental 580A, 10 0 eV, calibrated <br /> to isobutylene) Sampling ports were installed upstream of the vacuum blower inlet to recover SVE <br /> influent air flow vapor stream samples, and downstream of the catalytic converter to recover effluent <br /> SVE air flow samples to monitor the efficiency of hydrocarbon destruction Field measurements <br /> were recorded at regular intervals throughout the pilot test and are summarized in Table 5 <br /> 32 COLLECTION AND ANALYSIS OF VAPOR EXTRACTION AIR FLOW SAMPLES <br /> IA total of four pairs of extracted air flow vapor samples were collected from the influent and effluent <br /> of the regenerative vacuum blower unit to measure concentrations of hydrocarbon vapor The <br /> samples 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 either Precision Enviro-Tech Analytical Laboratory (PETAL) or McCampbell <br /> A�r.Y_.4 Laboratory <br /> L.. �.,r.. /T A 7 1 T],.,.1_., !"�..1 F Each 1., 1.�..u.i �l. ri 'I—11� ra <br /> t naly�lcal La ora o y (MA.L') in A achcco, Caliioirma Each sample vv as ana�yzeal vviu11-1 111�k—Urs <br /> of collection for TPH-g and BTEX in accordance with EPA Methods 5030/8015 Modified and 8020 <br /> 4.0. FINDINGS <br /> Ground water elevation, flow direction and gradient were determined Isom field data collected on <br /> • Advanced CeoEnvironmental,Inc <br />