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h'q KL FIN FELDER I I 4. PILOT TEST DESIGN AND EXECUTION This section describes the pilot test design and execution. As mentioned in Section 3, it is proposed to operate the pilot test for one week. The first day will test high flow air sparging in the pilot test well during which soil vapor extraction will be performed in the same well. The following four days will test low flow ozone sparging without the use of soil vapor extraction. The sections that follow outline the design of the pilot test well, the equipment that will be used to complete the pilot test, and the operating strategy proposed. 4.1 PILOT TEST WELL DESIGN I To take advantage of the monitoring wells already present at the site, Kleinfelder will construct the pilot test well in the vicinity of the original AS/SVE-1 well. In addition to being an area of high historical contaminant concentrations, the location facilitates monitorixg the system effects with several nearby wells including MW-DIS-1, AS/SVE-1 (two screens), NP-1 (4 screens), AS- SVE-2 (two screens) and NP-2 (two screens). The proposed location is presented on Plate 2. It is proposed to advance the well to 140 feet below grade and include two sparge points and a single vent well. The sparge points will be located just above two apparent areas of clayey soil at 90 and 140 feet below grade. The SVE well will be screened from 15 to 35 feet below grade. The two sparge wells and the SVE well will be constructed in the same borehole with appropriate bentonite annular seals in between as shown on Plate 3. The SVE well will consist of 2-inch diameter schedule 40 PVC screened with 0.02" slotted pipe. The vent wellhead will be completed with a 2-inch schedule 40 PVC ninety containing a 114-inch threaded port with a valve at the top for sampling. There will be a 2-inch PVC ball valve on the lateral run. A pressure gauge will be threaded into the side of the ninety for vacuum monitoring, and a 114-inch threaded port will be included approximately 12 inches down from the valve for flow monitoring. The sparge wells will consist of 1-inch diameter Schedule 40 PVC with specially designed Spargepoints® placed at the design depths. Spargepoints° were selected rather than screened pipe because is generates smaller bubbles (11100 the size of bubbles generated with 0.010" slotted pipe) that better permeate tight and/or heterogeneous soils and distributes more evenly with less likelihood of groundwater mounding or flow channeling. The sparge wellheads will include a check valve, pressure gauge, shutoff valve and a pressure regulator. A reinforced plastic 1-inch airline will connect from the pilot system to the AS wellhead. The borehole for the pilot test well will be advanced with an 8-inch hollow stem auger. During installation of the pilot test well, soil samples will be collected at five-foot intervals with a 2-inch 12280/2002R476 Page 11 of 26 Copyright 2002 Kleinfelder,Inc. May 17,2002