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t03 March 2004 <br /> AGE-NC Project No 01-0827 <br />' Page 2 of 6 <br />' 2.0. PROCEDURES <br /> Field procedures for ground water sampling are described below All field work was performed in <br /> t accordance with Central Valley Regional Water QuahtyControl Board(CVRWQCB)guidelines for <br /> the investigation of underground storage tank (UST) sites <br /> 21 OZONE SPARGE SYSTEM OPERATION <br />' The ozone air-sparging (OS) system began operation on 01 July 2003 An oxygen condenser and <br /> ozone generator was fitted into a compressed air-stream through a throttled venture This flow stream <br /> is then connected to a manifold, under a timer cycled into the IAS wells using 3/8-inch diameter <br />' PVC tubing to the two-inch diameter network via under ground piping The OS system delivers 10 <br /> standard cubic feet per minute (scfin) at a pressure of 20 pounds per square inch, adequate to <br /> displace the static water within each sparge well <br /> The OS system was monitored and serviced at regular intervals throughout the quarter On <br />� . 17 December 2003 and 14 January 2004 dissolved oxygen(DO) and oxidation/reduction potential <br /> (ORP)in ground water wells adjacent to the IAS wells were measured Dissolved oxygen has shown <br /> a moderate increase in ground water wells since the initiation of operation of the remediation system <br /> in July 2003 (Appendix A) <br />' 2 2 QUARTERLY WELL MONITORING <br /> On 17 December 2003, the depth to ground water was measured in monitoring well VW-2d, in <br /> addition the well was purged and sampled On 09 January 2004,the depth to ground water measured <br /> in monitoring wells and then VW-2d and the deep well MW-6 were purged and sampled Monitoring <br /> wells MW-1 through MW-5 and vapor wells VW-1, VW-3 and VW-5d were not sampled due to <br /> several quarters of nondetectable concentrations of contaminants of concern <br /> 1 2 2 1 Well Monitoring and Evacuation <br /> On 17 December 2003, a Solinst water level meter was used to measure the depth to ground water <br /> in vapor well VW-2d After water levels were gauged, a dedicated disposable bailer was used to <br /> purge the wells of a minimum of three casing-water volumes (approximately 8 gallons) of ground <br /> water Temperature, pH, and conductivity were measured at regular intervals during purging using <br /> an Oakton model water analyzer Purged water from impacted wells was stored on-site in 55-gallon <br /> . drums The field data sheets are included in Appendix A <br />