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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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

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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