DOE Long-Term Surveillance and Maintenance Conference November 16, 2010 Dr. Dawn Kaback Principal Geochemist AMEC Geomat

1. Independent Technical Reviews for Groundwater Remediation Projects at DOE Sites DOE Long-Term Surveillance and Maintenance Conference November 16, 2010 Dr. Dawn Kaback Principal Geochemist AMEC Geomatrix, Inc.

2. DOE Groundwater Remediation Challenges • National Academy of Science 2009 Review • Contaminant behavior in the subsurface is poorly understood • Contaminant and hydrogeological site characteristics may limit usefulness of baseline remediation technologies • Long-term performance of caps, liners, and reactive barriers cannot be assessed with current knowledge

3. Some Examples of Groundwater Remediation Challenges • Hanford: contamination moving in unexpected amounts and/or directions (Pu under Z crib) • Hanford 300 Area: PA predicted plume would shrink to meet standard within 10 years • Oak Ridge: mercury in fish and aquatic life continues to increase • Idaho RWMC: initial PA predictions of contaminant migration to water table ~100,000 yr; new estimate ~decades

4. Independent Reviews • Why • They provide another perspective and a check for challenging problems • They bring a broad experience base with alternative solutions • Review panel can address politically sensitive issues as an independent body • They can reduce risk and uncertainty • How • Engage the panel early in the project and continue reviews as project is implemented • Develop specific objectives to ensure focus • Provide sufficient background information for review prior to site visit/workshop and consider pre-workshop conference call • Engage regulators in the workshop • Panel debrief followed by written report are essential

5. Independent Reviews Scope and Structure • Scope • Specific problem for a single project • Specific problem for a project that has broad applicability at one site and others • General problem • Proposal review • Structure • Single or multiple workshops that produce specific recommendations and report • Could include follow-on laboratory or field work or other analysis • Key Features • Multi-disciplinary team • Broad experience base (industry, national labs, universities, DOE contractors)

6. History of Independent Reviews • 2003 Technical Assistance Program formalized and initiated • More than 30 reviews completed within two years • Review process adopted by some sites • External Technical Reviews used primarily by the Technology Innovation and Development Office of Waste Processing • Technical Assistance for groundwater and soils supported through SRNL Center for Sustainable Groundwater and Soil Solutions

7. External Technical Review Process Identified Possible Questions • Does the design under review meet project objectives and requirements? • What issues could prevent successful implementation? • What data are needed to support critical project decisions? • Are technical objectives well defined? • Have alternatives been identified and evaluated? • Is technology development planned? • Are the technical bases substantial and adequately documented? • Is quality assurance adequate?

8. External Technical Review Recommended Report Format • Findings • Observations that would prevent the alternative from being implemented (i.e. fatal flaws) • Technical Issues • Observations requiring resolution • Areas of Concern • Observations that may require design modifications or additional testing • Opportunities for Improvement • Good Practices

9. Examples and Benefits of Independent Reviews…..

10. Hanford Chromium Plume 100-D Area • Two reviews to evaluate performance of In Situ Redox Manipulation Barrier • Recommended ways to mend barrier • Recommendations provided input to remedial design • Chromium workshop brought industry experience to further support remedial planning • Two reviews: initial proposal and project review for Columbia River Projects • ZVI injection, electrocoagulation, bioremediation, and source investigation • Supported remedial design • Bioremediation incorporated into overall plan • Source investigation successfully located a large hot spot

11. Hanford: Radionuclides in the Deep Vadose Zone • Problem: radionuclides in deep vadose zone • cannot be destroyed like organics • too deep for excavation • provide long-term source to groundwater • Multiple waste sites in the Central Plateau where depth to groundwater is ~200 feet • Contaminants of concern: technetium, uranium, strontium, etc. • At some sites, contaminants have reached the water table; at some they have not • Treatability test is investigating different methods for immobilization of radionuclides • Cutting-edge applied R&D

12. Hanford Deep Vadose Zone Treatability Test • Two strategies: desiccation and reactive gas injection • both laboratory and field testing • Independent reviews incorporated into the treatability test process • Two panels (desiccation and reactive gas) convened multiple times to review plans and recommend improvements • Recommendations improved test and monitoring design for desiccation field test • Simplified test design • Improved monitoring network design and instrumentation • Reactive gas panel recommendations stress need for additional lab testing prior to a hot test in the field

13. Workshop 1: Desiccation Pilot Test Design Recommendation • Consider performing test with single injection well and single extraction well • Rationale • Two-well system is easier to implement, monitor, and model • Fewer monitoring locations are necessary to evaluate two-well system than radial flow system • System will have much greater certainty of vapor flow paths • Desiccation can still be evaluated/demonstrated

14. 2nd Workshop: Panel Observations and Recommendations • Air-flow testing provided valuable data • Simplified test geometry is fully supported • Revised monitoring plan is comprehensive • Plans to control input air (humidity & temperature) promising • Lab test results describe drying front migration • PA modeling to predict long-term performance should be applied to test site • 1-D tracer testing provides a good foundation • Monitoring should continue for > 5 years after desiccation

15. Reactive Gas Workshop: Panel Recommendations • Lab results promising but further research crucial • Evaluate unintended consequences • Identify mechanism for uranium sequestration • Clarify benefits and drawbacks • Conduct modeling of dissolution/reprecipitation • Conduct shallow clean test first to demonstrate ammonia delivery to the target zone • Consider an injection-extraction system to deliver gas to low permeability zones • Continue investigation of alternatives

16. Other Hanford Reviews • Geophysics • Subsurface characterization • General geophysics applications • Seismic and EM (preferential pathways) • Resistivity (Tc-nitrate) • Groundwater Modeling for RI/FS • Groundwater Surface-Water Interaction • Remedial System Evaluation of 200-ZP/PW-1 Operable Units • Environmental Restoration Disposal Facility

17. Fernald Future Groundwater Treatment System • Objectives: evaluate and recommend a cost-effective post-closure groundwater- wastewater treatment system • Recommend system to remove and dispose of TSS • Reduce footprint (90%) of existing Advanced Waste Water Treatment (AWWT) facility to support design of Converted Advanced Waste Water Treatment (CAWWT) facility • CAWWT to satisfy ROD requirements • Place AWWT demolition materials in OSDF before closure • Evaluated ~5 options for managing TSS • Recommended Multi Media Filters (existing equipment) for removal • Recommended active excavation for disposal

18. Fernald Passive Treatment of Uranium-Contaminated Leachate from the On Site Disposal Facility • Objectives • evaluate treatment options for passive system to treat leachate • team from national laboratory, academia, DOE contractor, and industry • design and conduct field test at Fernald • prepare test plan • design and procure equipment • conduct and monitor tests • prepare written report • Treatment Tests • Small-scale test: ZVI, ABM, GFO, Dowex, GAC • Large-scale test: ZVI, ABM • ZVI performed the best • Questions: ask Stan Morrison

19. Fernald Directional Drilling for Collection of Under-Building Soil Samples • Problem: characterize radionuclides in soil beneath a new building (large tanks fill the floor space) to obtain regulatory acceptance for closure • Data needed for closure planning, including OSDF disposal volume estimation • Soil must meet final remediation levels (FRLs) to obtain closure • Directional drilling with coring performed (first application of this technology) • 16 soil samples collected from 4 boreholes drilled under the building • Project completed ahead of schedule and under budget

20. Examples of Other Reviews • Oak Ridge • Mitigation & Remediation of Mercury at Y-12 • Delineation of DNAPL • Environmental Waste Management Disposal Facility • Portsmouth • X-701B Groundwater Remedy • On Site Waste Disposal Facility • Paducah • C-400 Thermal Treatment Remedial Design and Site Investigation • On-Site Waste Disposal Facility • Pinellas • Offsite Contaminants

21. Conclusions • Many groundwater remediation challenges remain at DOE sites • Independent technicalreviews can provide added value • Bring broad-based, practical experience • Provide a sanity check • Focus on science and engineering • Help with regulatory and stakeholder acceptance • Multi-disciplinary teams are key to success