Former NAS Moffett Field
Site 26 Eastside Aquifer Treatment SystemSite 26 Eastside Aquifer Treatment System
Neil Hey, PGShaw Environmental, Inc.
Valerie Harris PEValerie Harris, PENavy BRAC PMO West
S t b 8 2011September 8, 2011RAB Meeting
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Presentation Overview
• Treatability Study Update
• Focused Feasibility StudyFocused Feasibility Study
• Schedule
• Questions
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Site 26 Treatability Study - Location
3Note – inset location not to scale
Treatability Study Purpose
Evaluate the applicability and effectiveness ofEvaluate the applicability and effectiveness of EHC®, an in situ abiotic/biotic treatment technology to reduce the chemicals of concerntechnology, to reduce the chemicals of concern (COC; PCE, TCE, DCE, & VC) concentrations in groundwater to levels below the ROD cleanup g pstandards at IR Site 26
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EHC® Treatment Technology
• A product of Adventus Americas, Inc.
• Patented combination of zero valent iron (ZVI)• Patented combination of zero-valent iron (ZVI) particles & plant-based carbon
• Combination of chemical (abiotic) and biological (biotic) reductive dechlorination processes
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Project Description
• Installed 5 observation wells
• Injected EHC® at 16 locations
• Performed 10 post-injectionpost-injection groundwater monitoring events
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g
Site LocationEHC® Injection
Total CEs ~80 µg/L
50 ft x 50 ft area
40 to 8 feet bgs
~6,600 gallons6,600 gallons hydrant water
~23 000 poundsGroundwater Flow
~23,000 pounds EHC®
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Treatment Area Results
82 µg/L total82 µg/L total
2 µg/L total4 µg/L total
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Treatment Area Results
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TS Conclusions
• EHC® easy to prepare but difficult to injectEHC® t di t ib t d if l d t h t• EHC® not distributed uniformly due to heterogeneous nature of subsurface
• Complete reductive dechlorination observed in all treatment area wells
• 98% reduction in total COCs concentration in treatment areaarea
• PCE, TCE, & DCE concentrations in treatment area reduced below ROD cleanup standards in < 1 yearVi l hl id i i i• Vinyl chloride concentration in treatment area remains slightly above ROD cleanup standard but decreasing
• EHC® continues to treat on-flow of COCs 2 years after
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ytreatment
Focused Feasibility Study
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Site 26 Background
• Chlorinated solvents identified in groundwater near Hangar 3 in 1983
• Record of decision (ROD) signed in 1996. Selected remedy was groundwater extraction and treatmentremedy was groundwater extraction and treatment to restore groundwater to cleanup standards.
• Cleanup standards – drinking water– Tetrachloroethene (PCE) = 5 g/L– Trichloroethene (TCE) = 5 g/L
C 2 d hl h 6 /– Cis-1,2-dichloroethene = 6 g/L– Vinyl chloride = 0.5 g/L
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Site 26 Background (continued)
• Eastside Aquifer Treatment System (EATS) began q y ( ) goperating in 1999. – extracted 67 million gallons of water– removed 23.7 pounds of chlorinated volatile organic
compounds (VOCs)• Shut down in 2003 to evaluate:• Shut down in 2003 to evaluate:
– Evaluate plume stability– Chemical rebound– Natural attenuation– HRC in plume hot spots
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– Treatability study (almost completed)
2010 Groundwater Plume
Combined CVOC concentrations• 85.9 g/L (maximum) located near current treatability studystudy• Max combined CVOC concentration in other areas b t 25 /about 25 g/L
TREATABILITY STUDY AREA
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Groundwater Flow
Focused Feasibility Study
Purpose – to evaluate several technologies along with the selected remedythe selected remedy
• Identify remedial action objectives and applicable regulations
• Identify and screen treatment technologies– Monitored Natural Attenuation– Abiotic/Biotic Treatment (EHC®)– In Situ Biostimulation/Bioaugmentation
• Develop and evaluate remedial alternatives against• Develop and evaluate remedial alternatives against seven of the nine NCP criteria
• Compare the remedial alternatives against each other
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• Compare the remedial alternatives against each other
Preliminary Remedial Alternatives
• Alternative 1 – No Action
• Alternative 2 – Monitored Natural Attenuation (MNA)(MNA)
• Alternative 3 – Optimized Pump and Treat
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Preliminary Remedial AlternativesPreliminary Remedial Alternatives
• Alternative 4 – Abiotic/biotic Treatment and MNA
• Alternative 5 – In Situ Biostimulation /Bi t ti d MNA/Bioaugmentation and MNA
Biotic PCE
TCE
VC
Cis 1,2‐DCE Trans 1,2‐DCE
VC
Ethene
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Ethane
β‐eliminationα‐elimination
Conceptual Treatment Areas
•Trend analysis performed forperformed for each well
•Identify areas th t ld b fitthat could benefit from treatment
Natural
Natural processes = 60 years
processes > 60 years (increasing trend/no
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trend/no trend)
Sustainability
• An evaluation of sustainability will be included in the feasibility study (FS)in the feasibility study (FS)
• FS will use SiteWiseTM
Streamlined life cycle analysis tool– Streamlined life-cycle analysis tool – Developed by Navy, Army Corps and Battelle– Available at http://www.ert2.org/t2gsrportalAvailable at http://www.ert2.org/t2gsrportal
• Sustainability metrics considered are:– Energy and resource consumptiongy p– Greenhouse gas and criteria pollutant emissions– Water and ecological impacts
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– Worker and community safety
ScheduleSchedule
• November 30, 2011- Draft FS Report p
• December 1, 2011 to January 29, 2011 – Agency/RAB Review of draft g y/
• April 30, 2012 - Final FS Report
Next Steps
– Proposed planProposed plan
– ROD amendment
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Questions?
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