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
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
Acknowledgements
Laurie Haines, Army Environmental Center
Lt. Col. Tom DeVenoge, US Air Force
Javier Santillian, AFCEE
Erica Bevcar, AFCEE
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
Outline
Background on technical impracticability
Key findings from AEC study
Key findings from Air Force study
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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
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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
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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
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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
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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
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
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
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
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
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
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
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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
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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.
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
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
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
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?
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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
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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
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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
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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
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Survey Results: Identify Candidate Sites
More Data
Needed3 sites (8%)
Potential ARAR Waiver
Candidate16 sites (41%)
ARAR Waiveris not Likely Appropriate
20 sites (51%)
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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
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
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
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
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
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
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.
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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.
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
Questions?
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Extra Slides
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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
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
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
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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
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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)
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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
INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS AND CONSULTANTS
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
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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
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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
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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
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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
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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
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Anniston Army Depot, Alabama
Coldwater Spring
TI Zone in Unweathered
Bedrock
Site
TI Zone in Residuum
and Weathered Bedrock
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Source: Mobile District, 1995
Hydrogeologic Complexity
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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