Optimizing Cleanup at Complex Sites using Technical Impracticability (TI) Waivers

Transcription

1 Optimizing Cleanup at Complex Sites using Technical Impracticability (TI) Waivers Robert O Laskey, Elisabeth L. Hawley, Rula A. Deeb, Michael C. Kavanaugh Malcolm Pirnie, Inc JSEM Conference Columbus, OH

2 Acknowledgements Laurie Haines, Army Environmental Center Lt. Col. Tom DeVenoge, US Air Force Javier Santillian, AFCEE Erica Bevcar, AFCEE

3 Outline Background on technical impracticability Key findings from AEC study Key findings from Air Force study

4 TI Waivers One of Six Types of ARAR Waivers Technical Impracticability Waiver 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 compliance with ARARs is technically impracticable from an engineering perspective within a reasonable timeframe Where remedy results in greater risk Where remedies result in equal benefit Where remedies will be later implemented Where a state standard has not been consistently implemented Where money would be better spent elsewhere AEC TI Waiver Document, 2002

5 Technical Impracticability Definition No 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

6 EPA Policy and Guidance EPA 1993 Guidance EPA 1995 Implementation Memo Consistent Implementation of the 1993 Guidance (OSWER Directive ) EPA Region Fact Sheet on TI Decision Making

7 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 Outcome of Independent Technical Reviews Source zone clean up not linked to risk due to dissolved plume Strategies within existing programmatic framework

8 Malcolm Pirnie s Report for AEC Introduction 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

9 Key Findings TI Waivers 1. 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

10 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

11 Complexities Leading to TI Physical (5) 10% Technology (6) 13% Contaminant (21) 44% Economic (3) 6% Geology (4) 8% Contaminant+ Geology (9) 19% Nearly 75% of TI waivers are needed due to contaminant and/or geologic considerations

12 Assessing Site Complexity (NRC, 1994) Contaminant Characteristics Hydrogeology Mobile, Dissolved (degrades/ volatizes) Mobile, Dissolved Strongly Sorbed, Dissolved (degrades/ volatizes) Strongly Sorbed, Dissolved Separate Phase LNAPL Separate Phase DNAPL Homogeneous, single layer Homogeneous, multiple layers Heterogeneous, single layer Heterogeneous, multiple layers Fractured 1* *Relative ease of cleanup, where 1 is easiest and 4 is most difficult

13 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.

14 Data Basis at Time of TI Waiver Application Site Investigation / Remedial Investigation Pilot Studies Front-End TI Waivers Feasibility Study (FS) Full-Scale Operation Post-Implementation TI Waivers Unknown Number of Sites

15 Performance Metrics in the Source Zone Success Metrics in the 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? What success metrics are appropriate for measuring achievement of cleanup goals in the dissolved plume? PERFORMANCE METRICS SUCCESS METRICS Source Zone (SZ) GW flow Dissolved Plume

16 Stakeholder Perspectives Successful 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

17 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

18 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

19 TI Waivers Granted at DOD Sites Three 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

20 Survey Results: Identify Candidate Sites ARAR Waiver is not Likely Appropriate 20 sites (51% ) Potential ARAR Waiver Candidate 16 sites ( 41% ) More Data Needed 3 sites (8% )

21 TI Waiver Candidate Ranking Site Ranking AFB Name 1 Air Force Plant 6 2 Cape Canaveral 3 Hanscom AFB 4 Edwards AFB-18 5 George AFB-SS030 6 Tinker AFB-Bldg Mather AFB-SD57 8 Altus AFB 9 McClellan AFB-GW OU 10 Edwards AFB-ExoticFuel 11 Beale AFB 12 Williams AFB 13 George AFB-NorthDisposal DNAPL/LNAPL present? Depth >100 ft? Area Geology Other Constraints Stakeholder Interest Timeframe Cost Saving Data Basis Strongly supports TI waiver Supports TI waiver Neutral Counters TI waiver Strongly counters TI waiver Note: Edwards AFB site 37 not analyzed; TI waiver already incorporated into final remedy.

22 Recommendations After detailed review SITE Air Force Plant 6 Beale AFB Cape Canaveral AFS George AFB Hanscom AFB RECOMMENDATION TI waiver integration into the final Statement of Basis Containment zone integrated into final ROD TI waiver is not appropriate at this time TI waiver is likely a necessary component of the ROD amendment TI waiver should be included in the final ROD as a contingency measure

23 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

24 References EPA, Guidance for evaluating the technical impracticability of ground-water restoration. OSWER Directive EPA, Consistent Implementation of the FY 1993 Guidance on Technical Impracticability of Ground-water Restoration at Superfund Sites. OSWER Directive EPA Superfund Information Systems Record of Decision System (RODS) ( Malcolm Pirnie, Technical impracticability waivers: Guidelines for site applicability and the application process Phase I report. Prepared for the U.S. AEC, January.

25 References, cont d Malcolm Pirnie, Technical Impracticability assessments: Guidelines for site applicability and implementation Phase II report. Prepared for the U.S. AEC, March. National Academies of Sciences, Contaminants in the Subsurface: Source Zone Assessment and Remediation. NRC, Alternatives for Ground Water Cleanup. National Academies Press. NRC, Environmental Cleanup at Navy Facilities: Adaptive Site Management. National Academies Press.

26 Questions?

27 Extra Slides

28 DNAPL/Source Zone Issues Have Been Discussed in Several Books and Studies EPA, DNAPL Remediation: Selected Projects Approaching Regulatory Closure EPA, The DNAPL Remediation Challenge: Is There a Case for Source Depletion? Environment Agency, Illustrated Handbook of DNAPL Transport and Fate in the Subsurface ITRC, DNAPL Source Reduction: Facing the Challenge

29 Task 2, AFP 6 Background Basis 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

30 Task 2, AFP 6 Recommendation 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

31 Task 2, Beale AFB Background 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 H 2 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)

32 Task 2, Beale AFB Recommendation 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

33 Task 2, Cape Canaveral Background Basis 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/ prb.pdf

34 Task 2, Cape Canaveral Recommendation 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

35 Task 2, George AFB Background Basis for TI Model indicates that the upper plume cannot be completely contained; different pumping scenarios are unable to meet RAOs within 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

36 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-andtreat 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)

37 Task 2, Hanscom 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

38 Task 2, Hanscom AFB Recommendation 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 wellformulated 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

39 Anniston Army Depot, Alabama Site TI Zone in Residuum and Weathered Bedrock TI Zone in Unweathered Bedrock Coldwater Spring

40 Hydrogeologic Complexity Source: Mobile District, 1995

41 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