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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