ARCHIVED REPORTS_THIRD QUARTER 2011 SITE STATUS, REMEDIAL SUMMARY, AND GROUNDWATER MONITORING REPORT

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Stantec L & M OPERABLE UNIT-THIRD QUARTER 2011 SITE STATUS, REMEDIAL SUMMARY, AND GROUNDWATER MONITORING REPORT Status of Remediation Activities October 28, 2011 Historical DPE system operations and analytical data are presented in Tables 10 through 17. Chemical concentrations and mass removal graphs are presented on Figures 31 through 34. Analytical lab reports and field data sheets for all O&M activities are presented in Appendix H. 3.2 L&M OU AND APARTMENT SOIL VAPOR EXTRACTION SYSTEMS 3.2.1 L&M OU and Apartment Soil Vapor Extraction Systems Summary The L&M OU SVE (SVE) and Apartment SVE (ASVE) systems have run near continuously since May 31, 2007. The SVE system is comprised of horizontal vapor wells: SVE-1 through SVE-11, a 100-gallon liquid/vapor separator, and a Solleco 500 cfm vapor extraction system with a Roots URAI 59 20-hp positive displacement blower. The ASVE system is comprised of horizontal wells (ASVE-1 through ASVE-6), a 100-gallon liquid/vapor separator, and a Solleco 250 cubic feet per minute (cfm) vapor extraction system with a Roots URAI 56 10-hp positive displacement blower. Vapor from both the SVE and the ASVE systems is abated with a 750 scfm thermal oxidizer. Since May 31, 2007 the 750 scfm SVE and ASVE vapor abatement system has been operated under SJVAPCD permit number N-4878-2-0. 3.2.2 L&M OU and Apartment Soil Vapor Extraction Systems Operational Data— 3Q11 Both the SVE and ASVE systems were approximately 91% operational during 3Q11 (83 out of 91 days). Both systems were found down on arrival on July 13, 2011 due to a knock out level sensor alarm. The sensor was fixed and the systems were restarted. The systems were shut down from July 15 to July 20, 2011 to accommodate the 3Q11 monitoring and sampling event. No other interruptions to operation occurred for either system during the remainder of 3Q11. Sampling and analysis for TPHd via EPA Method TO-17 was initiated on August 11, 2011 for both the SVE and ASVE systems. A calculation error was identified in the ASVE data tables and revisions have resulted in new values for recovery rates and total mass removed. Recovery calculations now assume one-half the detection limit when a compound is reported as less than the detection limit. 3.2.3 L&M OU Soil Vapor Extraction System Analytical Data— 3Q11 During 3Q11 (June 16, 2011 through September 15, 2011) the SVE system removed approximately 20.41 lbs (3.35 gallons) of TPHg, 1.69 lbs (0.23 gallons) of TPHd, 0.045 lbs (0.006 gallons) of benzene, and 0.10 lbs (0.016 gallons) of MtBE from the subsurface. To date the SVE system has removed approximately 4,157 lbs (681 gallons) of TPHg, 1.69 lbs (0.23 gallons) of TPHd, 2.86 lbs (0.39 gallons) of benzene, and 5.74 lbs (0.93 gallons) of MtBE from soil vapor beneath the L&M OU. Historical SVE system operations and analytical data are presented in Tables 21 through 24. I:\Tidewater\TW Stockton(P2A)\QMRs\2011\3Q11\3011 QSSR QRSR QMR Stockton_FINAL.doc 3.2