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r A. Teichert& Son Mobile Equip Shop 103 N. 'E' St. Stockton, CA. SVE Pilot Test Work Plan Feb 1994 3. 1.2 Vapor Well Construction One 4-inch diameter vapor extraction/monitoring well will be constructed in the soil boring. The well will be constructed of schedule #40 PVC well screen and riser pipe. We anticipate the well will be screened from approximately 45 feet below ground surface to total depth. Backfill from the former UST excavation extends to approximately 38 feet bgs in this location. The well screen is expected to consist of 0.010 and 0.020-inch machine slotted #40 pipe. Number 3 sand filter pack will be emplaced through the augers around the well screen from total depth to two feet above the top of the well screen. The well will be developed by the surge and bail method prior to the emplacement of approximately 2 feet of expansive bentonite pellets forming a seal between the filter pack and the grout sanitary seal. The well will be pressure grouted with neat cement/bentonite grout from the bentonite seal to near surface, where a traffic-rated vault will be emplaced in a concrete pad. The wellhead installation will be compatible with the expected design elements of a SVES. The conceptual well is illustrated in Figure 2. 3.2 Vadose Zone Characterization and Product Concentration Soil samples collected from the vadose zone will be logged in accordance with the Unified Soil Classification System. Samples will be screened with a calibrated organic vapor monitor for headspace analysis of VOC in ppmv. The field screening will be utilized to select samples for laboratory analysis; a minimum of six soil samples are expected to be analyzed. The soil sample laboratory analytical results will be included in a data base summarizing current and historical laboratory and soil boring data. The data base will be utilized to construct a cross section and iso-concentration map of hydrocarbon concentrations. The hydrocarbon iso-concentration map will be utilized to estimate quantity and mass of hydrocarbons in place to be remediated. 3.3 Pilot Test Procedures 3.3. 1 Vapor Extraction The pilot test will assess the air flow potential and hydrocarbon concentrations generated by the flow from the newly constructed well. Vacuum will be monitored in adjacent wells MW-13, 12, 11 and 10. The test will utilize the equipment identified in Appendix B, and will be completed in accordance with BCR's standard procedures included in Appendix A. These procedures include the construction of a blower curve, calculation of air flow, VOC concentration curve, average well yield, VOC mass • extraction rate and the radius of influence of the test from the vapor test well. • 3 •