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

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
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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
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4. Basewide GW - Plumes
2007 TCE Plume 2008 TCE Plume
Site 28
TCE GW Plumes
Upper Portion of
the A Aquifer
N
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5. Basewide GW - Plumes cont.
2007 TCE Plume 2008 TCE Plume
Site 26
TCE GW Plumes
Upper Portion of
the A Aquifer
N
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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
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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
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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
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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
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12. Site 26 Pilot Test Status cont.
Insert a graph or two showing concentration over time
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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
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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
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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
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16. Questions?
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