Scaling gas-phase treatment of vadose-zone contaminants for field application at the Hanford site - 15133
- Pacific Northwest National Laboratory (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 at the U.S. Department of Energy's Hanford site. 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. Ammonia-vapor treatment of uranium relies on induced sediment dissolution and precipitation processes that decrease the amount of mobile uranium in the vadose zone. Previous laboratory studies have demonstrated the decrease in uranium mobility caused by ammonia treatment. As part of development efforts for the ammonia technology, scale-up issues were identified and have been addressed through a series of laboratory and modeling efforts. Key scale-up elements are scoping calculations to support treatment design and understanding ammonia transport. Recent research has extended the concept of geochemical manipulation by ammonia to investigate a combined-gas treatment for sequestering Tc-99 in the vadose zone. The technique uses a combination of geochemical Tc-99 reduction with hydrogen sulfide gas and induced sediment mineral dissolution and precipitation with ammonia vapor, creating conditions for deposition of stable precipitates that decrease the mobility of Tc-99. Laboratory experiments have demonstrated the effectiveness of this treatment under a variety of operational and sediment conditions important to the scale-up and evaluation of potential addition field applications. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
- OSTI ID:
- 22822692
- Report Number(s):
- INIS-US-19-WM-15133; TRN: US19V0682067607
- Resource Relation:
- Conference: WM2015: Annual Waste Management Symposium, Phoenix, AZ (United States), 15-19 Mar 2015; Other Information: Country of input: France; 16 refs.; Available online at: http://archive.wmsym.org/2015/index.html
- Country of Publication:
- United States
- Language:
- English
Similar Records
Remediation of Uranium in the Hanford Vadose Zone Using Gas-Transported Reactants: Laboratory Scale Experiments in Support of the Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau
Remediation of Technetium in Vadose Zone Sediments Using Ammonia and Hydrogen Sulfide Gases
Related Subjects
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
AMMONIA
CONTAMINATION
DISSOLUTION
GEOCHEMISTRY
GROUND WATER
HYDROGEN SULFIDES
MINERALS
PRECIPITATION
RADIONUCLIDE MIGRATION
REMEDIAL ACTION
SEDIMENTS
SIMULATION
TECHNETIUM 99
URANIUM
US DOE
VAPORS