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1 DOE Long-Term Surveillance and Maintenance Conference November 16, 2010 Dr. Dawn Kaback Principal Geochemist AMEC Geomatrix, Inc. Independent Technical.

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Presentation on theme: "1 DOE Long-Term Surveillance and Maintenance Conference November 16, 2010 Dr. Dawn Kaback Principal Geochemist AMEC Geomatrix, Inc. Independent Technical."— Presentation transcript:

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

2 2 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 DOE Groundwater Remediation Challenges

3 3 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 Some Examples of Groundwater Remediation Challenges

4 4 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 Independent Reviews

5 5 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 ) Independent Reviews Scope and Structure

6 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 History of Independent Reviews

7 7 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? External Technical Review Process Identified Possible Questions

8 8 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 External Technical Review Recommended Report Format

9 9 Examples and Benefits of Independent Reviews…..

10 10 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 Hanford Chromium Plume 100-D Area

11 11 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 Hanford: Radionuclides in the Deep Vadose Zone

12 12 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 Hanford Deep Vadose Zone Treatability Test

13 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 14 2 nd 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 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 16 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 Other Hanford Reviews

17 17 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 Fernald Future Groundwater Treatment System

18 18 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 Fernald Passive Treatment of Uranium-Contaminated Leachate from the On Site Disposal Facility

19 19 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 Fernald Directional Drilling for Collection of Under-Building Soil Samples

20 20 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 Examples of Other Reviews

21 21 Conclusions Many groundwater remediation challenges remain at DOE sites Independent technical reviews 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

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