View
597
Download
0
Category
Tags:
Preview:
DESCRIPTION
Former Moffett Federal Airfield Base-Wide Groundwater Program Update: Presentation to the Moffett Restoration Advisory Board Meeting September 10, 2009
Citation preview
Former NAS Moffett Field
September 10, 2009 - Moffett RAB MeetingGroundwater 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
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
4
Basewide GW - Plumes
2007 TCE Plume 2008 TCE PlumeSite 28
TCE GW Plumes
Upper Portion of the A Aquifer
N
5
Basewide GW - Plumes cont.
2008 TCE PlumeSite 26
TCE GW Plumes
Upper Portion of the A Aquifer
2007 TCE Plume
N
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
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
8
Basewide GW 2009 Work
N
2009 performed:
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
Site 26 Potentiometric Surface Map
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
10
Site 26 Pilot Test - Location
Note – inset location not to scale
11
Site 26 Pilot Test - Location
12
Site 26 Pilot Test Status cont.
Insert a graph or two showing concentration over time
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
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
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
16
Questions?
Recommended