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01 May 2000 <br /> AGE-NC Project No 95-0121 <br /> Page 3of7 <br /> 4 r <br /> I air flow was monitored using a Dwyer DS-200 flow sensor The flow rate was determined from the <br /> measured differential pressure and the piping diameter using a nomograph (Appendix C) The vapor <br /> stream at the SVE inlet was monitored for the presence of organic vapor using an organic vapor <br /> analyzer(OVA) equipped with a photo-ionization detector(PID Thermo Environmental 580A, 10 0 <br /> eV, calibrated to isobutylene) Sampling ports were installed upstream of the vacuum blower inlet <br /> 4 <br /> to recover influent soil-gas vapor stream samples, and downstream of both carbon canisters to <br /> Irecover effluent stream samples to monitor the efficiency of hydrocarbon filtration Field <br /> measurements were recorded at regular intervals throughout the pilot test and are summarized in <br /> Table 4 <br /> 3 2 'COLLECTION AND ANALYSIS OF SOIL GAS SAMPLES <br /> A total of six extracted soil-gas vapor samples were collected from the inlet and outlet of the <br /> regenerative vacuum blower unit to measure concentrations of hydrocarbon vapor The samples were <br /> collected in Tedlar bags using an organic vapor analyzer as an air pump <br /> Following sample collection,the samples were placed in a covered container and transported under <br /> chain-of-custody to Precision Enviro-Tech Analytical Laboratory (PEAL) in Stockton, California <br /> Each sample was analyzed witlun 72 hours of collection for TPH-g and BTE&X in accordance with <br /> EPA Method TO-14 <br /> 4.0. FINDINGS <br /> b <br /> Ground water elevation, flow direction and gradient were determined from field data collected on <br /> 26 January 2000, the contaminant impact to ground water was assessed from the ground water <br /> laboratory data <br /> From laboratory analysis of three inlet soil-gas vapor samples collected during operation of the SVE <br /> pilot test between 15 February 2000 and 29 March 2000, AGE prepared an estimate of the mass of <br /> hydrocarbons extracted by the SVE system - <br /> 41 RELATIVE GROUND WATER ELEVATION AND GRADIENT <br /> The depths to ground water in wells MW-1, MW-2, MW-3, MW-4, MW-5, MW-6 and MW-7 were <br /> measured between 15 79 and 17 07 feet below the tops of the well casings Ground water elevations <br /> at the site were calculated to be between 9 44 feet and 10 22 feet below mean sea level, ground water <br /> elevations are depicted in Figure 3 Ground water elevation at the site increased an average 0 60 feet <br /> Advanced GeoEmironmental,Inc <br /> I <br />