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' 29 July 2005 <br /> i AGE-NC Project No 01-0827 <br />' Page 2 of 5 <br />' 21 OZONE SPARGE SYSTEM OPERATION <br /> The ozone-spargmg(OS) system has operated at the site since July 2003,the system was monitored <br />' and serviced at regular Intervals throughout the quarter The OS system consists of an ozone <br /> generator,which produces ozone-rich air at a minimum of 10 standard cubic feet per minute(scfm) <br /> and apressure of 20 pounds per square inch This ozone-rich air is delivered to wells IAS-1 through <br />' IAS-3 and well OZ-1 via a subsurface network of 3/8-inch polyethylene tubing <br /> Because the injected ozone will eventually break down to dissolved oxygen(DO), a DO meter was <br />' utilized at each monitoring well during the monitoring events to determine the effectiveness of ozone <br /> sparging During the second quarter sampling event,DO and/or oxidation/reduction potential(ORP) <br /> in ground water wells adjacent to the IAS wells were measured prior to purging the wells,during the <br /> well purging,and after the wells were purged Dissolved oxygen values from the three wells sampled <br /> (MW-6, VW-2D, and VW-5D) generally remained stable in the shallow wells during sampling, a <br /> decrease of DO was observed in the deep monitoring well MW-6 during the purging. process <br />' Negative ORP values increased in the monitoring wells near ozone Injection wells during the purge <br /> process (Appendix B) <br /> 10 Generally, sampling concentrations have declined in ground water wells since remediation system <br /> startup in July 2003 <br /> 1 <br /> 2 2 QUARTERLY AND MONTHLY WELL MONITORING <br /> On 15 June 2005, the depth to ground water was measured in monitoring wells MW-1 through <br /> MW-6 and vapor wells VW-2d and VW-5d <br /> I <br /> 2 2 1 Well Monitoring and Evacuation <br /> 1 A Sohnst water level meter was used to measure the depth to ground water In each well After water <br /> levels were gauged,a Waterra inertial tubing pump or dedicated disposable bailer was used to purge <br /> monitoring wells MW-6 and vapor wells VW-2d and VW-5d of a minimum of three casing-water <br /> volumes (between 9 and 16 gallons) of ground water Temperature, pH, and conductivity were <br /> measured at regular intervals during purging using an Oakton model water analyzer Additionally, <br /> ORP in wells adjacent to the IAS wells were measured Purged water from impacted wells was <br /> stored on-site in 55-gallon drums The field data sheets are included in Appendix B <br /> r <br /> Advanced GeoEnvironmental,Inc <br /> I <br />