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Stantee SECOND QUARTER 2009 OPERATIONS MAINTENANCE AND MONITORING REPORT SHOP 10 MAINTENANCE STATION Remediation System Operation and Maintenance July 31, 2009 4.0 Remediation System Operation and Maintenance The ASISVETS operated continuously from startup on December 1,'2005,.through June 27, 2007; except for brief shut downs for monthly maintenance. The system was shut down on June 27, 2007, until December 5, 2007 and operated under a new contract with Caltrans. The system was restarted on December 5, 2007, and operated continuously through June 25, 2009, except for brief maintenance periods. The total time of operation of the system was approximately 31 months. The system was shut down on June 25, 2009, due to low levels in system influent and to begin the Site closure process. There were no reported violations of SJVAPCD air permit conditions during operation of the SVETS. I 4.1 SOIL VAPOR EXTRACTION SYSTEM OPERATION During the Second Quarter 2009, the SVETS removed approximately 289 pounds of volatile organic compounds (VOCs) at an average rate of 5.3 pounds per day, and operated at 93 percent uptime with an average SVE flow rate of 95 scfm. The temperature difference across the catalyst bed during this quarter was zero due to low levels of contaminant in influent. The flow ratelof the catalytic oxidizer unit for this quarter was consistent with previous system operation. The SVE system was down from March 12, 2009, to April 23; 2009, .for high temperature and autodialer malfunction. d , Since startup in 2005, the catalytic oxidizer has operated a total of approximately 22,450 hours at an average inlet temperature of 732 degrees Fahrenheit and has treated 28,1'48 pounds (an average 29.1 lbs/day) of VOCs at a destruction efficiency of an average 95.6 percent over the life of the system. A ,F summary of AS/SVETS data and mass calculations are shown in Table 4. Cumulative mass of a hydrocarbons removed and mass removal rates are plotted in Figures 6 and 7. i, Samples of system influent and effluent air streams were collected on April 23, May 18, and June 25, 2009, and analyzed by Test America, a state of California, DHS-certified analytical laboratory located in Irvine, California. Vapor samples were analyzed for TPHg, BTEX, and methyl tertiary butyl ether(MTBE) by US EPA Method TO-3. Additionally, the air samples collected on April 23, May 18, and June 25, 2009, �. were also analyzed for TPHd by National Institute for Occupational Safety and Health (NIOSH) Method 1550. Vapor sample laboratory analytical reports and CDCs issued during the reporting period are included in Appendix A. Combined inlet vapor concentration from both vapor extraction wells have decreased to less than 100 parts per million per volume (ppmv) in June 2009 from a high of 1,858 ppmv in December 2006 (Table 4). No significant rebound was recorded following system shutdowns from ,lune to December 2007 (23 weeks), December 2008 through January 2009 (six weeks), or following a six-week shutdown from March 2009 through April 2009. The valve to well VEW-1 was closed partially on,March 28, 2008, to concentrate vacuum on well VEW-2, which increased total inlet concentrations briefly. Treatment system total VOC influent concentrations have declined steadily and have been below 200 ppmv since February 2009. js 51usi 329-f05LsecOr5project-051caltrans\stockton-shop Mom&m and gw reporlingl204972nd qtr 200Mg2_09 omm_fnl.doc 4-1_