1 DOE Long-Term Surveillance and Maintenance Conference November 16, 2010 Dr. Dawn Kaback Principal...
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Transcript of 1 DOE Long-Term Surveillance and Maintenance Conference November 16, 2010 Dr. Dawn Kaback Principal...
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DOE Long-Term Surveillance and Maintenance Conference
November 16, 2010
Dr. Dawn Kaback Principal GeochemistAMEC Geomatrix, Inc.
Independent Technical Reviews for Groundwater Remediation Projects
at DOE Sites
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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
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• 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
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• 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
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• 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
VISTA ENGINEERINGTECHNOLOGIES, L.L.C.
VISTA ENGINEERINGTECHNOLOGIES, L.L.C.
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• 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
History of Independent Reviews
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• 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
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• 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
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Examples and Benefits of Independent Reviews…..
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• 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
Test Location
ISRM Barrier
Application target: reduce fluxof O2, NO3
-, and Cr6+ into ISRM
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• 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
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• 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
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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
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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
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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
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• 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
Resistivity through tank farm
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• 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
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• 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
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• 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
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• 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
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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