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24 August 2001 • AGE-NC Project No 98-0448 Page 3 of 7 3 1 SOIL VAPOR EXTRACTIONIIN-SITU AIR SPARGE SYSTEM PROCEDURES Between 16 April 2001 and 30 June 2001, the SVE and IAS remediation systems were operational at the site The SVE system utilized a model Fuji, 3-horsepower regenerative vacuum blower and two 55-gallon carbon canisters to extract and adsorb hydrocarbon vapor from the subsurface Two- inch diameter, schedule 80 PVC piping was installed underground from wells VW-1 through VW-5 to the inlet of the regenerative vacuum blower, the outlet from the vacuum blower was routed through two sequential 55-gallon carbon canisters A Magnehelic vacuum gauge was attached to the inlet of the blower, air flow was monitored at the inlet using a Dwyer DS-200 flow sensor A flow rate was determined from the measured differential pressure and the piping diameter using a nomograph(Appendix B) The SVE air flow at the influent and effluent was monitored routinely for the presence of organic vapor using an organic vapor analyzer (OVA) equipped with a photo- ionization detector (PID Thermo Environmental 580A, 10 0 eV, calibrated to zsobutylene) Sampling ports were installed upstream of the vacuum blower inlet to recover SVE influent air flow vapor stream samples, and downstream of the vacuum blower to recover effluent SVE air flow samples to monitor the efficiency of hydrocarbon destruction Field measurements were recorded at regular intervals between 16 April and 30 June 2001 and are summarized in Table 5 � i 3 2 COLLECTION AND ANALYSIS OF VAPOR EXTRACTION AIR FLOW SAMPLES Between 16 April and 30 June 2001, a total of ten extracted air flow vapor samples were collected from the influent and effluent of the regenerative vacuum blower unit to measure concentrations of hydrocarbon vapor The samples were collected in Tedlar bags using a hand air-vacuum pump Following sample collection, the samples were placed in a covered container and transported under chain-of-custody to either McCampbell Analytical Laboratory (MAL) in Pacheco, California or Precision Enviro-Tech (PET) in Stockton, California Each sample was analyzed,within 72 hours of collection for TPH-g and BTEX in accordance with-EPA Methods 5030/8015 Modified and 8020 r T- 4.0. FINDINGS -_ - - I - -- - - - -- - _ - - - _ r —, AGE determined ground water flow direction and gradient from the field data collected on 23 April 2001, the contaminant impact to ground water was assessed from the laboratory data From field data collected at the SVE remediation system between 16 April and 30 June 2000, AGE determined the average TPH-g concentration, the average flow rate and calculated the approximate mass and volume of hydrocarbons removed iAdvanced GeoE nviron mental,Inc I