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1 r � " ' i a 07 July 2000 AGE-NC Project No 98-0448 ' Page 10 of 12 4 2 3 Soil Vapor Extraction Monitonng Activities I The vacuum blower unit will be monitored weekly using a photo-ionization detector (PID) and ' Dwyer DS-200 flow sensor to ensure optimal destruction of recovered hydrocarbon vapors, and to monitor cleanup progress The PID readings will be recorded from the influent end of the vacuum blower unit, and recorded before and after carbon adsorption Operational parameters (air flow, air ' vacuum and volume of processed vapor) will be measured on a weekly basis to ensure optimal destruction of recovered hydrocarbon vapors ' Vapor samples will be collected on a monthly basis from the influent and effluent end of the vacuum blower utilizing the vacuum pump on a Model 580A organic vapor meter (Thermo Environmental Instruments Inc ) The samples will be collected in Tedlar bags and transported to a DTSC-certified ' laboratory in a chilled container under ice and transported under chain-of-custody procedure , I During the "start-up"period for the SVE system, organic vapor and operational parameter will be fmonitored on a daily basis The anticipated start-up period will be approximately one week 4 3 IN--SITU AIR SPARGING SYSTEM DESIGN ' Initiation of an IAS system is proposed within the core petroleum hydrocarbon-impacted area, IAS is proposed in conjunction with SVE concurrently at the site The proposed IAS system would comprise of an electric air compressor to inject air beneath the water table using air spargmg wells ' The compressor will provide between 5 and 15 pounds per square inch (psi) of air to each air sparge well The injected air will volatilize dissolved hydrocarbons in ground water, and force hydrocarbon vapors into the vadose zone, where they can be withdrawn by the SVE system 1 The proposed IAS system will one existing ground water monitoring wells (MW-4B) located near the former UST area in addition to four proposed new IAS wells Approximate air sparging well ' locations are depicted in Figure 4 ' 43 1 In-situ Air Spargmg Well Installation Installation of five IAS injection wells are proposed utilizing a limited access truck-mounted drill rig equipped with 8-inch diameter hollow stem augers Hollow stem augers will be cleaned prior to advancement in each borehole The IAS injection wells will be advanced to depths of approximately 30 feet,bsg The IAS injection wells will be completed with 2-inch diameter, schedule 40 PVC casing emplaced through the hollow stern augers, utilizing five feet of slotted well casing (0 020- inch) from 30 to 35 feet bsg A #3 Lonestar Lapis Luster sand will be poured down the annulus ' Advanced GeoEnvi ron mental,Inc