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Forty feet of two-inch diameter PVC tubing will be installed at the base of the trench, The tubing will be slotted at five foot intervals The 2-inch diameter PVC tubing will house a cluster of 3/8 inch diameter polyethylene tubing that will deliver surface air to diffusing filters within the slotted 2 inch PVC at S foot intervals Each 3/8-inch diameter tubing will be connected to a manifold through individual adjustable flow meters at the surface that will allow the even distribution of surface air to the slotted 2 inch PVC tubing at the base of the trench Following the installation of the air sparging tubing, the 20-foot deep trench and will be backfilled with pea gravel to 7 feet bgs Forty feet of two-inch diameter slotted PVC tubing will be installed horizontally in the trench above the top of water and connected to the surface with blank tubing The tubing will be connected to a vapor extraction system via a restricted orifice manifold capable of measuring the volume of airflow through the VE system The vapor extraction tubing will be covered with five feet of pea gravel to within 2 feet of surface and finished to grade with compacted ABS and asphalt to form a tight seal over the vapor extraction piping Two temporary wells will be installed vertically in the pea gravel backfill of the trench during the installation of the horizontal piping One temporary well will be constructed of 6-inch diameter PVC It will be used to purge water from the trench during the installation of the air sparging and VE piping and later to control groundwater levels within the trench for vapor extraction A second well will be constructed of 2-inch diameter PVC and will be used to collect groundwater samples from the trench area Both wells will be slotted from the base of the trench to dust above the current top of groundwater The surface seal of the wells will be completed as described for the offsite monitoring well in Task III of this workplan AIR SPARGING /VAPOR EXTRACTION EQUIPMENT The air sparging tubing will be connected via a manifold at the surface to an electric oilless pump capable of conveying 1-2 cfm of ambient surface air to the submerged dispersal piping within the trench The vapor extraction tubing in the trench will be connected to an electric powered Rotron blower capable of extracting subsurface vapors at a rate of 40 scfm The vapors will be extracted through a manifold equipped with an orifice plate, sample ports, and control valves to allow the measurement of airflow and vacuum created by the system while collecting representative vapor samples during the course of the pilot test Measurements of vacuum and airflow created by the extraction system will be made with water or mercury filled manometers Four WestStates/Calgone Vent Scrub 200 carbon canisters will be used in series to treat the extracted vapors The piping between each canister and the exhaust stack exiting the fourth canister will contain sampling ports to determine when breakthrough has occurred See Figure 5 for a diagram of the pilot test extraction and treatment system 9