Moffett Base-Wide Groundwater Update, September 10, 2009

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Former Moffett Federal Airfield Base-Wide Groundwater Program Update: Presentation to the Moffett Restoration Advisory Board Meeting September 10, 2009

Former Moffett Federal Airfield Base-Wide Groundwater Program Update: Presentation to the Moffett Restoration Advisory Board Meeting September 10, 2009

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  • 1. Former NAS Moffett Field September 10, 2009 - Moffett RAB Meeting Groundwater Program Update Presented by Julie Crosby-Brooks
  • 2. Presentation Overview • Basewide groundwater • 2008 annual groundwater report results • 2009 groundwater elevation measurements • Site 26 pilot test update • EHC injection complete • Groundwater sampling in progress • Site 28 pilot test update • Pilot test approach 2
  • 3. Basewide Groundwater - Topics 2008 annual groundwater report submitted in June 2009 • November and December 2008 groundwater sampling • March and November 2008 groundwater elevation measurements • WATS operation summary • Report highlights and conclusions 2009 groundwater elevation measurements 3
  • 4. Basewide GW - Plumes 2007 TCE Plume 2008 TCE Plume Site 28 TCE GW Plumes Upper Portion of the A Aquifer N 4
  • 5. Basewide GW - Plumes cont. 2007 TCE Plume 2008 TCE Plume Site 26 TCE GW Plumes Upper Portion of the A Aquifer N 5
  • 6. Basewide GW - WATS West-side Aquifers Treatment System (WATS) 2008 operation summary • Up-time: 98.9% • Treated and discharged over 36 million gallons of water • Removed approximately 365 pounds of volatile organic compounds (VOCs) • 96% of mass removed is TCE and DCE • Submitted NPDES permit renewal January 2009 • Existing permit is effective in interim • New permit – 10/2/09 6
  • 7. Basewide GW Report 2008 annual groundwater report highlights • Site 28 – collected samples from more wells than previous year, better definition of plume boundary • Site 26 – pilot test on-going 2008 annual groundwater report conclusions • Site 28 - plume generally stable, overall decreasing VOC trend, groundwater flow continues to be to the north • Site 26 – plume generally stable, overall decreasing VOC trend, groundwater flow continues to be to north - northwest 7
  • 8. Basewide GW 2009 Work 2009 performed: Site 26 Potentiometric Surface Map Collected basewide groundwater elevation measurements in March 2009 2009 planned/in progress: Well maintenance (locks, bolts, etc.) at wells noted as having deficiencies Basewide GW sampling in November & December Basewide GW elevation measurements in November N 8
  • 9. Site 26 Pilot Test Status Background • Objective is to evaluate the effectiveness of EHC to reduce VOC contamination at Site 26 – Collect site specific data – Verify ability to cost-effectively reduce VOC contamination to below ROD cleanup levels in a reasonable amount of time Approach • Inject EHC at higher-concentration lobe near Hangar 3 • Collect groundwater samples to evaluate contaminant degradation (baseline, one-month, and quarterly) • Collect performance boring samples to visually confirm radius of EHC injection • Summarize and evaluate in final pilot test/treatability study report 9
  • 10. Site 26 Pilot Test - Location Note – inset location not to scale 10
  • 11. Site 26 Pilot Test - Location 11
  • 12. Site 26 Pilot Test Status cont. Insert a graph or two showing concentration over time 12
  • 13. Site 26 Pilot Test Status cont. Preliminary results and trends • PCE and TCE destroyed to < MCLs at some treatment zone wells • DCE concentrations increasing • VC – no big change • Performance borings show that EHC was distributed to at least 7 feet from injection point over 80-90% of the vertical profile • Complete dechlorination evident – ethene and ethane production 13
  • 14. Site 26 Pilot Test Status cont. Preliminary conclusions • EHC appears to be effective at completely reducing VOCs to innocuous chemicals based on ethane and ethene concentrations • DCE is increasing Path Forward • Finish quarterly sampling • Submit final report that evaluates data and recommends path forward 14
  • 15. Site 28 Pilot Test Approach Background • VOC plume commingled with contamination from MEW and NASA – Began preparation of regional Feasibility Study (FS) – Several parties are conducting pilot tests to augment FS Approach • Additional characterization of potential DNAPL areas – Membrane Interface Probe (MIP) sampling in 3 areas – Navy, EPA, WB, Shaw evaluate data & trends • Inject substrate (EHC?) to reduce VOC concentrations • Groundwater sampling to evaluate effectiveness • Final report 15
  • 16. Questions? 16