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Corrective Action plan Montgomery Ward Auto Service Center, Stockton, CA There will be two header lines extending from the remediation unit to each well One of these will be a 4-inch header pipe that will be used for vacuum extraction The other header line will be a 2-inch line that will be used for air injection Since the extraction wells are all 2-inch wells, the 4-inch header line will be reduced to a 2-inch line before connecting to the wells The 4-inch is required in order to accommodate the total flow when two or more wells are being extracted simultaneously Once the trenches are excavated, they will be partially filled with pea-gravel The pipe runs will then be laid down on top of the pea gravel At the well-head, each vapor extraction well will be manifolded such that it can be used as either an extraction well, or as a passive/active injection well This configuration will allow the most flexibility during operations and will be used to remediate the site effectively Each well-head will also be equipped with sampling ports that will allow the monitoring of vacuum and vapor concentrations Once the piping connections are all completed, a test will be performed to ensure that all the connections and fittings are air tight After ensuring that there are no leaks, the trenches will be backfilled and the surface will be matched to existing grade Each well- head connection will be set inside a traffic rated box and cover that will provide access to the well connections and sampling ports The well-cover will be flush with surface grade ' Installation of Fuel and Utility Services Electric power required for the remediation system will be pulled from the main electric panel located inside the Montgomery Ward Auto Service Center Building (see Figure 13) This will ensure that the power supply to the building at the Montgomery Ward Site is not interrupted Gas and water supplies also may be installed, as necessary ' Installation of Vapor Extraction and Treatment Unit A thermal or catalytic oxidizer will be used to treat the extracted vapor prior to discharge t to the atmosphere Montgomery Ward is currently reviewing specific details of available types of these units along with costs to determine the most optimum unit to be used at the site At a minimum, specifications that will be necessary are as follows ' Vacuum Pump 15 HP Air-flow rate at recommended vacuum of 15" Hg 300 to 400 scfm Destruction Efficiency 96 to 99 % ' The unit will be equipped with the following knockout pump, flow meter and pressure gauges Installation of Air S ar inn Unit and Air S ar¢in Well-Head Connection The air sparging system will essentially involve the installation of an air compressor to force air into the wells at desired rates of 5 to 20 scfm at a pressure of 30 psi The sparging unit will also be equipped with a timer so that pulsed mode of air sparging can be 1IITI>I_ ___��..a TL.. r ll also have -al our f'{n1ar meter will a pressure gange so that air e111G11ed IHU tAilil will ui�v i,uvti uii uia ��.�� _..t.. S flow rates and pressures can be monitored Project No 1232 - 25 - ' SAB WORD 1232CAP