Deep Vadose Zone Treatability Test for the Hanford Central Plateau: Interim Post-Desiccation Monitoring Results, Fiscal Year 2014

Technical Report · Mon Sep 01 00:00:00 EDT 2014

DOI:https://doi.org/10.2172/1170496· OSTI ID:1170496

Truex, Michael J. ^[1]; Strickland, Christopher E. ^[1]; Johnson, Christian D. ^[1]; Johnson, Timothy C. ^[1]; Clayton, Ray E. ^[1]; Chronister, Glen B. ^[1]

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1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Over decades of operation, the U.S. Department of Energy (DOE) and its predecessors have released nearly 2 trillion L (450 billion gal.) of liquid into the vadose zone at the Hanford Site. Much of this discharge of liquid waste into the vadose zone occurred in the Central Plateau, a 200 km² (75 mi²) area that includes approximately 800 waste sites. Some of the inorganic and radionuclide contaminants in the deep vadose zone at the Hanford Site are at depths below the limit of direct exposure pathways, but may need to be remediated to protect groundwater. The Tri-Party Agencies (DOE, U.S. Environmental Protection Agency, and Washington State Department of Ecology) established Milestone M 015 50, which directed DOE to submit a treatability test plan for remediation of technetium-99 (Tc-99) and uranium in the deep vadose zone. These contaminants are mobile in the subsurface environment and have been detected at high concentrations deep in the vadose zone, and at some locations have reached groundwater. Testing technologies for remediating Tc-99 and uranium will also provide information relevant for remediating other contaminants in the vadose zone. A field test of desiccation is being conducted as an element of the DOE test plan published in March 2008 to meet Milestone M 015 50. The active desiccation portion of the test has been completed. Monitoring data have been collected at the field test site during the post-desiccation period and are reported herein. This is an interim data summary report that includes about 3 years of post-desiccation monitoring data. The DOE field test plan proscribes a total of 5 years of post-desiccation monitoring.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1170496
• Report Number(s): PNNL-23731; 830403000
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
vadose zone
remediation
desiccation