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� E C 0 R <br /> SMr Michael lnfurna—SJCEHD <br /> March 13, 2003 <br /> Page 4 <br /> Remedial Well and System Installation <br /> Between July 8 and 15, 2002, a total of 20 ozone sparge wells (S-1 through S-20) and four vapor <br /> extraction wells (V-7 through V-10) were installed to depths ranging from approximately 30 to 45 feet <br /> bgs The analytical results of selected soil samples collected during the well installation are <br /> summarized in Table 1 and the details related to the well completions are summarized in Table 2 <br /> Following installation of the wells, the lateral ozone infection lines, soil vapor extraction lines, and <br /> remediation compound were installed The SVE lines were stubbed up into the remediation <br /> compound into a manifold that was connected to the 500 scfm catalytic oxidizer The 20 ozone <br /> Sparge pipes were stubbed up into a manifold and connected to the 6 cfm ozone infection skid and <br /> generator The location of piping runs and remediation compound are shown on Figure 3 The <br /> equipment layout within the compound is shown on Figure 4 Soil vapor extraction was initiated at <br /> the site on September 26, 2002, under Authority to Construct number N-4613-1-0, issued by the San <br /> Joaquin Valley Air Pollution Control District (SJVAPCD) Ozone sparging was initiated at the site on <br /> November 20, 2002 Details of the remediation well installation and system startup are described in <br /> SECOR's Remediation Well and Soil Vapor Extraction System Installation Report, dated November <br /> 27, 2002 <br /> Groundwater Monitoring <br /> Water Table Elevations and Gradient <br /> On January 10, 2003, SECOR personnel measured the depth to water in each of the ten site-related <br /> groundwater monitoring wells (Table 3) The depth to water was not measured in well MW-7 due <br /> access limitations A water level indicator was used to gauge the wells to the nearest 0 01 foot A <br /> groundwater elevation contour map indicates that groundwater flow is generally toward the south <br /> and southeast at a gradient ranging from 0 011 ft/ft to 0 025 ft/ft (Figure 4) Current and historical <br /> groundwater monitoring data are summarized in Table 3 <br /> Separate-Phase Petroleum Thickness <br /> Well gauging and sampling efforts for the first quarter 2003 did not detect separate-phase petroleum <br /> hydrocarbons (SP) in any of the wells monitored (Table 3) Historically, SP has not been present in <br /> the groundwater monitoring wells at the site <br /> Groundwater Sampling <br /> Well Purging <br /> Groundwater monitoring wells were purged using a submersible pump and disposable bailers until <br /> pH, temperature, and conductivity readings had stabilized Temperature, conductivity, and pH <br /> readings were recorded in the wells, at regular purge intervals of one casing volume, with a portable <br /> instrument that was calibrated before the wells were purged Water purged from the ten <br /> groundwater monitoring wells was stored in drums on site, pending characterization and disposal <br /> Domestic Well Groundwater Sampling Procedures <br /> Domestic wells were purged by turning on the water at the well, thus draining the well's holding tank <br /> and filling the tank with fresh water from the aquifer Once the tank has been recharged, water <br /> Riverbank-03-10 doe SECOR International Incorporated <br /> t <br />