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Title: Technical Basis for Gas-Phase Vadose Zone Remediation Technologies at Hanford: A Review - 12186

Conference ·
OSTI ID:22293484
; ; ;  [1]; ;  [2]
  1. Pacific Northwest National Laboratory, Richland, Washington (United States)
  2. CH2M Hill Plateau Remediation Company, Richland, Washington (United States)

In situ vadose zone remediation approaches are being evaluated as potential options to mitigate the transport of inorganic and radionuclide contaminants from the vadose zone to the groundwater. Some of the candidate approaches are based on changing the contaminant or subsurface conditions in a way that slows downward migration of the contaminants through the vadose zone using amendments delivered in the gas-phase. Two promising approaches that have undergone testing at Hanford include soil desiccation to address technetium-99 contamination and ammonia-induced sequestration of uranium. For soil desiccation, a dry gas is injected to desiccate a targeted portion of the subsurface and thereby decrease contaminant movement by removing moisture and decreasing the hydraulic conductivity of the desiccated zone. Ammonia-induced sequestration of uranium relies on changing the pore water chemistry, primarily through pH changes, to induce dissolution and precipitation processes that decrease the amount of mobile uranium in the vadose zone. (authors)

Research Organization:
WM Symposia, 1628 E. Southern Avenue, Suite 9-332, Tempe, AZ 85282 (United States)
OSTI ID:
22293484
Report Number(s):
INIS-US-14-WM-12186; TRN: US14V1138115008
Resource Relation:
Conference: WM2012: Waste Management 2012 conference on improving the future in waste management, Phoenix, AZ (United States), 26 Feb - 1 Mar 2012; Other Information: Country of input: France; 16 refs.
Country of Publication:
United States
Language:
English