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Tic n VV ASS OCIATES I N C . I Selected soil samples will be immediately placed in a cooler with ice and delivered under chain-of-custody documentation to a State-certified analytical laboratory . Soil samples will be analyzed for TPHg by EPA method 8015 ; BTEX by EPA method 8020; and MTBE, TBA, -I TAME , DIPE, and ETBE by EPA method 8260 . Similar to the VES, the actual radius of influence for each sparge well will vary and the effective radius of influence will be evaluated following long-term operation of the AS system. In-situ air sparging is the process of injecting air into the saturated zone via sparge wells. Sparge wells are designed with a screen interval at a depth approximately 15 to 20 feet below the water table. Pressurized air is forced out through the screen and into the saturated zone. The air foams 4 1 bubbles that rise to the unsaturated zone, carrying trapped and dissolved contaminants . Vapor extraction wells in the unsaturated zone capture sparged air, which is then treated through the vapor extraction system. The AS system will include a compressor, associated piping, control ! valves, pressure gauges, flow meters, instrumentation and controls; and a remediation shed shared with the VES . Based on ATC' s experience at similar sites and the results of the pilot tests, a Gast ( 2567-P 132-T908X rotary vane compressor would be sufficient to operate the air sparge component I. J of the system. The compressor would create a maximum of 20 pounds per square inch pressure and a maximum airflow rate of 18 standard cubic feet per minute. A process and instrumentation ( diagram for the AS is shown on Figure 14. L_J 5.2.3 Remediation System Layout (l Components of the vapor extraction and air sparge system would be located in an enclosed shed on the south side of the on-site building. This will preclude public access and reduce noise. A network of subsurface piping will be used to convey off gas from the extraction wells to the remediation shed. The trenching system layout is shown on Figure 15 . The same trenches will be used for the air sparge system. Piping will be used to convey air to the sparge wells for injection to the subsurface. Piping will be installed at a maximum depth of two feet as shown on Figure 16 . A two-foot by two-foot well vault will be installed over each vapor extraction and au sparge well. A gate valve will be installed at each well head to control the airflow in or out of the well. In addition, a sampling port will be installed at each vapor extraction well for monitoring purposes. ( % Equipment operation will require the installation of an electrical power source and meter base. Site system requirements include a 220V, single phase 150 amp power source and meter base. A NEMA 4, UL Listed Control Panel will be located at the shed. II 6.0 REMEDIATION SYSTEM CONSTRUCTION Upon review and approval of the remediation system design plans and specifications by PHSIEHD, I`J ATC will complete the following tasks. l � w:\wordpro\62596\reports\irp.doc 8 L:i