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L & M OPERABLE UNIT- FIRST QUARTER 2012 SITE STATUS, REMEDIAL SUMMARY, <br />AND GROUNDWATER MONITORING REPORT <br />April 30, 2012 <br />I:\Tidewater\TW Stockton (P2A)\QMRs\2012\1Q12\1Q12 QSSR QRSR QMR Stockton_FINAL.doc 3.1 <br />3.0 Status of Remediation Activities <br />3.1 DUAL PHASE EXTRACTION SYSTEM <br />3.1.1 Dual Phase Extraction Systems Summary <br />The dual phase extraction (DPE) system consists of groundwater extraction (GWE) and soil <br />vapor extraction (SVE) and utilizes wells DPE-1 through DPE-13, and 2AMW-14, a 100-gallon <br />liquid/vapor separator, and a Solleco 400- standard cubic feet per minute (scfm) thermal <br />oxidizer with a Travaini TRO 400s 25-hp liquid ring pump. <br />From March 18, 2004 through April 4, 2004, the system was operated to conduct source tests <br />for the San Joaquin Valley Air Pollution Control District (SJVAPCD) and the collection of effluent <br />Polycyclic Aromatic Hydrocarbon (PAH) sampling under Authority to Construct (ATC) number <br />N-4878-1-1. On July 7, 2004, the SJVAPCD issued a new ATC number (N-4878-1-2) for <br />permanent operation of the system. The system was re-started on August 2 and 3, 2004 for <br />collection of PAH samples. Following PAH sample collection; the system was shut down until <br />Site excavation activities were completed. Continuous operation of the DPE system was <br />re-commenced on December 14, 2004. On June 22, 2005, SJVAPCD issued a Permit to <br />Operate (PTO) number (N-4878). On September 8, 2006, SJVAPCD issued a PTO number <br />(N-4878-1-3) that excluded further sampling of PAH. <br />3.1.2 Dual Phase Extraction System Operational and Analytical Data – 1Q12 <br />The system was shut down with the approval of the RWQCB-CVR on October 13, 2011 <br />(Attachment A). Due to low mass removal rates, the system remained non-operational to <br />monitor the response in DPE-1 through DPE-13. Following the 2Q12 M&S event the system will <br />be rebound tested. During 1Q12, the DPE system processed approximately 3,712 gallons of <br />water that originating from rainwater, knock-out water, and/or purge water that was collected <br />during site monitoring and sampling. <br />Historically the DPE system (GWE and SVE combined) has removed approximately 18,023 lbs. <br />(2,955 gallons) of TPHg, 9,543 lbs. (1,329 gallons) of TPHd, 5,136 lbs. (674 gallons) of TPHo, <br />11.97 lbs. (1.62 gallons) of benzene, 3.47 lbs. (0.56 gallons) of MtBE, and 0.52 lbs. <br />(0.08 gallons) of TBA from water and soil vapor to date. Since system start-up groundwater <br />extraction has removed and treated approximately 6,711,576 gallons of water. <br />Historical DPE system operations and analytical data are presented in Tables 10 through 17. <br />Chemical concentrations and mass removal graphs are presented on Figures 31 through 34. <br />Analytical lab reports and field data sheets for all O&M activities are presented in Appendix H.