Moffett Superfund Site 26 Update to the Moffett Restoration Advisory Board

transcript

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

Presentation Overview

• Treatability Study Update

• Focused Feasibility StudyFocused Feasibility Study

• Schedule

• Questions

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

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

Project Description

• Installed 5 observation wells

• Injected EHC® at 16 locations

• Performed 10 post-injectionpost-injection groundwater monitoring events

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®

Treatment Area Results

82 µg/L total82 µg/L total

2 µg/L total4 µg/L total

Treatment Area Results

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

ytreatment

Focused Feasibility Study

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

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

– 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

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

Preliminary Remedial Alternatives

• Alternative 1 – No Action

• Alternative 2 – Monitored Natural Attenuation (MNA)(MNA)

• Alternative 3 – Optimized Pump and Treat

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

Cis 1,2‐DCE Trans 1,2‐DCE

Ethene

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

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

– 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

Questions?