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' 01 October 2004 <br /> AGE-NC Project No 95-0173 <br /> Page 4 of 10 <br />' Various BTEX constituents were detected in 9 ground water samples collected from wells MW-2, <br /> MW-4,MW-13 (A-C),AW-1 (A and B)and AW-2(A and B)at concentrations as high as 2,780µg/l <br /> (xylene, AW-1B) The maximum benzene concentration detected was from sample AW-IB at a <br /> concentration of 360 gg/l <br /> 1,2-DCA was detected in the water sample collected from well AW-1 B at a concentration of 2 µ9l1 <br /> No other fuel components were detected in the samples analyzed Previous and current analytical <br /> results of groundwater monitoring well samples are summarized in Tables 3 and 4,respectively The <br /> GeoTracker confirmation pages ofthe submitted laboratory electronic deliverable format(EDF)files <br /> are included in Appendix C, the laboratory report (CTEL Project No CT214-0407045) and chain <br /> of custody forms are presented in Appendix D <br /> 3.0. SOIL VAPOR EXTRACTIONAN-SITU AIR SPARGE SYSTEM <br /> Between 24 March 2004 and 22 June 2004, an SVE remediation system was continuously operated <br /> at the site, utilizing a regenerative vacuum blower to selectively apply an induced vacuum to wells <br /> VW-1 through VW-4 During this time, IAS remediation was continuously operated at the site on <br /> • IAS well AW-213 (screened 60 to 70 feet bsg) utilizing an air compressor to inject air beneath the <br /> water table SVE and IAS procedures for the site were described in the AGE-prepared Remedial <br /> Action Work Plan dated 30 December 1998, and approved by the SJCEHD by letter dated 20 April <br /> 1999 <br /> 3 1 REMEDIATION SYSTEM PROCEDURES <br /> I The SVE system consists of a manifold network of two-inch diameter, schedule 80 PVC piping <br /> installed underground from SVE wells VW-1 through VW-7 to the inlet of the SVE remediation <br /> system The SVE remediation system comprises one 4%-horsepower,regenerative vacuum blower <br /> and two-1,000 pound carbon canisters <br /> In order to monitor efficiency of the SVE system 1) a Magnehelic vacuum gauge (Dwyer DS-200 <br /> flow sensor) was installed prior to the inlet of the SVE unit so that air flow is monitored, the flow <br /> rate was determined from the measured differential pressure and the piping diameter using a <br /> nomograph (Appendix E), 2) SVE air flow of the influent and effluent streams were 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 580B, 10 0 eV,calibrated to isobutylene), <br /> and 3) influent and effluent air flow vapor stream samples were collected from sampling ports <br /> installed upstream(influent)of the vacuumblowcr and downstream(effluent)of the carbon canisters <br /> and submitted for laboratory analysis Field measurements were recorded at regular intervals and are <br /> summarized in Table 6 <br /> Advanced GeoEnviron mental,Inc <br /> I <br />