ARCHIVED REPORTS_XR0011442 - Laserfiche WebLink

Home Browse Search

SEC0 ,R below the primary MCL of 13 pg/L to non-detectable concentrations in wells MW-22, MW-23, and MW-24 situated south and southeast of the site, in wells MW-11 and MW- 12 located west of the site, and in wells MW-13, MW-15, and MW-21 located southwest of the site. REMEDIAL PERFORMANCE SUMMARY An OS system has been operational at the site since December 2002. A summary of the operation of the OS system, and monthly groundwater sampling activities are presented in the following sections. A site plan showing the layout of the OS system is included as Figure 1. Ozone Injection Operation The OS system consists of a panel mounted KVA Associates (KVA) C-SpargeTm System that produces 4 grams per hour (0.009 pounds per hour) of ozone. Ozone is injected through 10 solenoids connected to wells SP-1/SP-6, SP-2/SP-7, SP-3/SP-8, SP-4/SP-9, SP-5, and SP-10 through SP-15. During the July 5, 2005 site visit, ozone was programmed to be injected into the following wells: SP-1, SP-3, SP-4, SP-5, SP-7, and SP-10 through SP-14. Following the replacement of the injection lines from the panel to the wells on September 19, 2005 for the purpose of repairing leaks and increasing system efficiency, the OS system was reprogrammed to inject ozone into wells SP-6 through SP-15. The system was restarted on September 20, 2005. Cumulatively, the OS system has operated for 10,002 hours, and has injected a total of approximately 90 pounds of ozone into the subsurface. Table 1 presents the operating data for the OS system, and includes operating hours and pressure readings. Remediation system field data sheets are included in Attachment 2. Monthly Groundwater Sampling To monitor the effectiveness of the OS system, groundwater samples are collected monthly from wells MW-3 and MW-10, and are submitted to STL for analysis of GRO, BTEX, and MtBE by EPA Method 82606. During the third quarter 2005, groundwater samples were collected from well MW-3 on July 7, 2005, and from wells MW-3 and MW- 10 on August 8, 2005 and September 20, 2005. SECOR attempted to sample well MW- 4 instead of well MW-10 on the July 7, 2005 site visit due to a work request error; however, the well was not accessible as a car was parked over the well. Results of monthly groundwater sampling events are summarized in Table 2. Remediation system certified laboratory analytical reports and chain-of-custody documentation are provided in Attachment 3. OS System Effectiveness Although the system had a low run time this quarter due to the removal and replacement of ozone lines and other minor repairs, the existing OS well network appears to be successfully remediating hydrocarbons dissolved in the groundwater beneath and downgradient of the USTs in the area of well MW-10. The results of quarterly groundwater monitoring since the startup of the OS system, and the results of monthly groundwater sampling of well MW-3 indicate the presence of declining GRO and MtBE vw_ concentration trends in wells MW-1 through MW-5; these wells are located in the vicinity 1:1ConocoPhiNips\Retai1 Sites1111951Reports\QSR&QRPS 2005/11195 QSR QRPS M051.doc