Optimizing Cleanup at Complex Sites using Technical ...proceedings.ndia.org/jsem2007/4219_Hawley.pdfINDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS Optimizing Cleanup

INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS

Optimizing Cleanup at Complex Sites using Technical

Impracticability (TI) WaiversRobert O’Laskey, Elisabeth L. Hawley, Rula A. Deeb,

Michael C. KavanaughMalcolm Pirnie, Inc.

2007 JSEM ConferenceColumbus, OH


Acknowledgements

Laurie Haines, Army Environmental Center

Lt. Col. Tom DeVenoge, US Air Force

Javier Santillian, AFCEE

Erica Bevcar, AFCEE


Outline

Background on technical impracticability

Key findings from AEC study

Key findings from Air Force study


TI Waivers – One of Six Types of ARAR Waivers

Greater Risk to Health and the Environment

Equivalent Standard of Performance Waiver

Interim Measure Waiver

Inconsistent Application of State Standard Waiver

Fund Balancing Waiver

Where remedy results in greater risk

Where remedies will be later implemented

Where remedies result in equal benefit

Where a state standard has not been consistently implemented

Where money would be better spent elsewhere

AEC TI Waiver Document, 2002

Technical Impracticability Waiver

Where compliance with ARARs istechnically impracticable from an engineering perspective within a reasonable timeframe


Technical Impracticability – DefinitionNo precise definition - It is a site-specific determination using EPA guidelines (EPA, 1993)

Rather, USEPA guidance identifies a process– For determining whether achieving remedial action

goals is “technically impracticable from an engineering perspective.”

– Based on feasibility, reliability, and cost


EPA Policy and Guidance

EPA 1993 Guidance EPA 1995 Implementation Memo – Consistent

Implementation of the 1993 Guidance (OSWER Directive

9200.4-14)

EPA Region 7 1997 Fact Sheet on TI Decision

Making


Army Response to DNAPL/Source Zone Clean Up Issues

Malcolm Pirnie (2002). Groundwater Evaluation and Development of Remediation Strategies Where Aquifer Restoration May Be Technically Impracticable http://aec.army.mil/usaec/cleanup/gwstrategy.pdf

– Outcome of Independent Technical Reviews

– Source zone clean up not linked to risk due to dissolved plume

– Strategies within existing programmatic framework

http://aec.army.mil/usaec/cleanup/gwstrategy.pdf


Malcolm Pirnie’s Report for AECIntroduction

TI – Definition and Context

TI Assessments

Findings and Recommendations

Results of Malcolm Pirnie Study of CERCLA Sites with TI Waivers

Detailed Site Summaries

Guidance Documents

Interview Summaries

http://aec.army.mil/usaec/cleanup/techimprac.pdf

http://aec.army.mil/usaec/cleanup/techimprac.pdf


Key Findings – TI Waivers1. TI is formally recognized, but underutilized as a

strategy.

2. Most granted due to complex hydrogeology and contamination

3. TI can be accepted before engineered remedies are implemented.

4. If TI is to be based on remedy performance, then performance metrics must be linked to metrics of success.

5. Stakeholder consensus is needed prior to pursuing a TI waiver


TI Waivers Granted at 48 CERCLA Sites

Colors differentiate the 10 USEPA Regions

TI Waivers included here represent those for groundwater cleanup.

Based on Malcolm Pirnie research as of September 2002


Complexities Leading to TI

Contaminant (21)44%

Contaminant+Geology (9)

19%Geology (4)

8%

Economic (3)6%

Physical (5)10%

Technology (6)13%

Nearly 75% of TI waivers are needed due to contaminant and/or geologic considerations


Assessing Site Complexity (NRC, 1994)

Contaminant Characteristics

*Relative ease of cleanup, where 1 is easiest and 4 is most difficult

Homogeneous,single layerHomogeneous,multiple layersHeterogeneous,single layerHeterogeneous,multiple layersFractured

2-3

2-3

3

3

3

2-3

2-3

3

3

4

3

3

4

4

4

1*

1

2

2

3

1-2

1-2

2

2

3

2

2

3

3

3

Mobile,Dissolved

(degrades/volatizes)

Mobile,Dissolved

(degrades/volatizes)

Mobile,DissolvedMobile,

DissolvedStronglySorbed,

Dissolved (degrades/volatizes)

StronglySorbed,

Dissolved (degrades/volatizes)

StronglySorbed,

Dissolved

StronglySorbed,

Dissolved

SeparatePhaseLNAPL

SeparatePhaseLNAPL

SeparatePhaseDNAPL

SeparatePhaseDNAPLHydrogeologyHydrogeology


NRC Findings Regarding Complex Sites

No reported cases of large DNAPL sites restored to drinking water standards.

Recent studies demonstrate that restoration of sites with DNAPL contamination to pre-contamination levels may not be practically achievable.

TI waivers are appropriate if RAOs* are clearly defined and if sufficient data illustrate that RAOs cannot be met by any feasible approach

Contaminants in the Subsurface: Source Zone Assessment and Remediation. National Academy of Sciences, 2005.


Data Basis at Time of TI Waiver Application

Post-Implementation TI Waivers

0 5 10 15 20

Unknown

Full-Scale Operation

Feasibility Study (FS)

Pilot Studies

Site Investigation / Remedial Investigation

Front-EndTI

Waivers

Number of Sites


Source Zone (SZ)

Dissolved Plume

For given cleanup goals in the dissolved plume…

What performance metrics for source zone depletion are appropriate to predict success in achieving cleanup goals in the dissolved plume?

Performance Metrics in the Source Zone → Success Metrics in the Dissolved Plume

PERFORMANCE METRICS ≠ SUCCESS METRICS

GW flow

What success metrics are appropriate for measuring achievement of cleanup goals in the dissolved plume?


Stakeholder PerspectivesSuccessful TI implementation depends on early and frequent discussions with regulators and other stakeholders and on maintaining a high level of credibility

Barriers to implementing TI– View that remediation systems are generally successful or

that less successful systems can be optimized

– General reluctance to waive an ARAR

– View of process as too burdensome

TI must be acceptable to stakeholders


Air Force Cleanup Program Policy Memorandum on SAF/IEE Performance-Based Management Policy (Oct 2004)– Simplify, improve and integrate processes– Apply performance-based philosophies– Align Air Force Cleanup Program with other existing DoD policy

Conduct all cleanup activities in accordance with applicable laws and regulations

Protect human health and the environment through response actions that are necessary, cost-effective and implementable

Review all site-specific remedial action cleanup goals and ARARs of federal and state laws to determine whether an ARAR waiver may be suitable


Project Rationale and Objectives

Rationale: Remediation of sites where it is technically impracticable to achieve ARARs poses higher financial risk to contractors with performance-based contracts (PBC) that specify regulatory closure.

Objective: Assist the Air Force in identifying and implementing ARAR waivers where appropriate


TI Waivers Granted at DOD SitesThree TI waivers granted at Air Force sites– Loring AFB, Maine, 1999 (Region 1)

– Pease AFB, NH, 1995 (Region 1)

– Eielson AFB, Alaska, 1998 (Region 10) (2 sites)

Other DoD sites– Schofield Barracks, Hawaii, 1997 (Region 9)

– Aberdeen Proving Ground, Maryland, 1997 (Region 3) (2 sites)

– Naval Air Development Center, Pennsylvania, 2000 (Region 3)

– Camp LeJeune Military Reservation, North Carolina, 1994 (Region 4)

– Camp Pendleton Marine Corps Base, California, 1995 (Region 9)

– PENDING Anniston Army Depot, Anniston, Alabama, 2007 (Region 4)

– POTENTIAL Air force sites


Survey Results: Identify Candidate Sites

More Data

Needed3 sites (8%)

Potential ARAR Waiver

Candidate16 sites (41%)

ARAR Waiveris not Likely Appropriate

20 sites (51%)


TI Waiver Candidate Ranking

Note: Edwards AFB site 37 not analyzed; TI waiver already incorporated into final remedy.

Strongly counters TI waiverCounters TI waiverNeutralSupports TI waiverStrongly supports TI waiver Strongly counters TI waiverCounters TI waiverNeutralSupports TI waiverStrongly supports TI waiver

Site

Ran

king

AFB Name DN

AP

L/LN

AP

L pr

esen

t?

Dep

th >

100

ft?

Are

a

Geo

logy

Oth

er C

onst

rain

ts

Sta

keho

lder

Inte

rest

Tim

efra

me

Cos

t Sav

ing

Dat

a Ba

sis

1 Air Force Plant 62 Cape Canaveral3 Hanscom AFB4 Edwards AFB-185 George AFB-SS0306 Tinker AFB-Bldg30017 Mather AFB-SD578 Altus AFB9 McClellan AFB-GW OU

10 Edwards AFB-ExoticFuel11 Beale AFB12 Williams AFB13 George AFB-NorthDisposal


Recommendations – After detailed review

SITE RECOMMENDATION

Air Force Plant 6 TI waiver integration into the final Statement of Basis

Beale AFB Containment zone integrated into final ROD

George AFB TI waiver is likely a necessary component of the ROD amendment

Cape Canaveral AFS TI waiver is not appropriate at this time

Hanscom AFB TI waiver should be included in the final ROD as a contingency measure


Summary

As sites with complex source zones are approaching the Remedy In Place stage, TI are being considered more frequently

One-third of the top 39 sites suggested by the Air Force may be candidates for ARAR waivers


ReferencesEPA, 1993. Guidance for evaluating the technical impracticability of ground-water restoration. OSWER Directive 9234.2-25.

EPA, 1995. Consistent Implementation of the FY 1993 Guidance on Technical Impracticability of Ground-water Restoration at Superfund Sites. OSWER Directive 9200.4-14.

EPA Superfund Information Systems Record of Decision System (RODS) (http://cfpub.epa.gov/superrods/srchrods.cfm)

Malcolm Pirnie, 2002. Technical impracticability waivers: Guidelines for site applicability and the application process –Phase I report. Prepared for the U.S. AEC, January.


References, cont’dMalcolm Pirnie, 2004. Technical Impracticability assessments: Guidelines for site applicability and implementation – Phase II report. Prepared for the U.S. AEC, March.

National Academies of Sciences, 2005. Contaminants in the Subsurface: Source Zone Assessment and Remediation.

NRC, 1994. Alternatives for Ground Water Cleanup. National Academies Press.

NRC, 2003. Environmental Cleanup at Navy Facilities: Adaptive Site Management. National Academies Press.


Questions?


Extra Slides


DNAPL/Source Zone Issues Have Been Discussed in Several Books and Studies

EPA, 2004. DNAPL Remediation: SelectedProjects Approaching Regulatory Closure

EPA, 2003. The DNAPL Remediation Challenge: Is There a Case for Source Depletion?

Environment Agency, 2003. Illustrated Handbook of DNAPL Transport and Fate in the Subsurface

ITRC, 2002. DNAPL Source Reduction: Facing the Challenge


BackgroundBasis for TI– TCE DNAPL present in fractured crystalline rock to

depths of 600 ft (Bldgs B4, B76, B58, B10, B90, offsite)

Remedial actions– ISCO in source zone, pump-and-treat (GAC), plume appears to be

stable

– Plan to incorporate TI waiver, bioremediation, MNA into final corrective action; Corrective Action Plan submitted to the State recently

Regulatory framework/Stakeholders– Several areas are designated RCRA sites

– Air Force, State of Georgia, Lockheed Martin, off-site property owners and RPs

– Cooperative group, partnering meetings for past 8 years

Task 2, AFP 6


RecommendationTask 2, AFP 6

Use of TI waiver to address deep bedrock contamination is appropriate at this time– Based on Corrective Action Plan findings, no

technologies are feasible to address deep bedrock contamination

In the future, another TI waiver may be needed to address residual contamination in the partially weathered rock (PWR)– State, Air Force have agreed to conduct additional

ISCO injections and collect more data prior to evaluating TI for the PWR


BackgroundTask 2, Beale AFB

Basis for TI (“Containment zone”)– TCE DNAPL in low-permeability sediments; lack of

technologies to meet MCLs within a reasonable timeframe without inordinate cost, per FS report

Remedial actions– Slurry wall as an interim RA, pilot H2 sparging in source zone

Regulatory framework/Stakeholders– CA RWQCB has primary oversight; AFCEE, RAB participate in

decision-making

– PBC in place (contractor is CH2M Hill)


RecommendationTask 2, Beale AFB

Use of TI zone “containment zone” is appropriate at this time– Containment zone strategy suggested by PBC

contractor and supported by base remedial project managers

Innovative use of performance-based contracting mechanism for implementing TI waiver– Could apply lessons learned to other Air Force sites


BackgroundBasis for TI– Two DNAPL source areas (180-acre plume) beneath

numerous buildings, structures where top-secret work is performed; cleanup timeframe estimated to be 610 years under MNA and 260 years after 75% source removal

Remedial actions– Air sparge system, vegetable oil injection, iron filings wall– Plan to pilot a co-solvent extraction study and study plume

capture

Regulatory framework/Stakeholders– RCRA site, currently RD/ developing Statement of Basis – EPA Region 4, State of Florida, RAB participate in partnering

meetings enviro.nfesc.navy.mil/erb/erb_a/ support/rits/presentations/2002-05-prb.pdf

Task 2, Cape Canaveral


RecommendationTask 2, Cape Canaveral

Recommendation is to NOT pursue a TI waiver at Hangar K at this time– Stakeholder expectations

– Relatively simple geologic setting

– Potential for meaningful reduction in source area mass

– Little benefit to the Air Force if TI waiver is implemented

Recommendation was based on information gained during telephone conversations with the base; not apparent from questionnaire response


Background

Basis for TI– Model indicates that the upper plume cannot be completely

contained; different pumping scenarios are unable to meet RAOswithin 100 years

Remedial actions– SVE in source areas– Extraction system that accelerates TCE migration into the lower

aquifer (shut down in 2002)

Regulatory framework/Stakeholders– CERCLA site with remedy-in-place, anticipated ROD amendment in

2007– EPA Region 9, CA RWQCB, AFCEE, City of Victorville, RAB are

decision-makers

Task 2, George AFB


Recommendation

Use of a TI waiver is appropriate and likely necessary in the ROD amendment– Initial modeling scenarios to optimize pump-and-

treat all indicate >100-yr timeframes, little or no benefit of pump-and-treat (vs. no action scenario)

– Diffuse plume, extremely limited biodegradation, mass stored in permeable lacustrine zone (PLZ)

Task 2, George AFB


Background

Basis for TI– TCE DNAPL present in fractured rock

and tied up in lacustrine layer

Remedial actions– Periodic injections of permanganate, then vapor extraction – “Dynamic” pump-and-treat system has been operating for 15

years (i.e., changes made to the system in 1995), interim ROD in place

Regulatory framework/Stakeholders– Site operates under CERCLA– EPA would like to see a final ROD in place by September 2007;

has offered to take the lead on modeling to develop remedial timeframes

Task 2, Hanscom AFB


RecommendationTask 2Task 2, Hanscom AFB

With the final ROD pending, best approach for Air Force is to incorporate a contingency TI waiver– Contingency would likely be triggered by empirical data

Data basis for a TI waiver has not yet been well-formulated– Basis of proposed model is not yet clear (system may be too

complex to model quantitatively)

– Other lines of evidence could be used to supplement modeling outcome


Anniston Army Depot, Alabama

Coldwater Spring

TI Zone in Unweathered

Bedrock

Site

TI Zone in Residuum

and Weathered Bedrock


Source: Mobile District, 1995

Hydrogeologic Complexity


TI Characteristics at ANAD– Complex geology – fractured media with variable matrix

porosity – conduit flow – flow models non-predictive

– DNAPL presence - confirmed in two shallow zones, inferred in deep zone (unweathered bedrock)

– Undefined pathways - from source areas to principle receptor not likely to be identified and modeled

– Ineffective interim actions - implemented with limited success in shallow zones

– Long remedial timeframe - ARARs cannot be reached in less than 100 years

– Inaccessible source zones - inferred in deep bedrock

– High remedial cost estimates