Gas-Phase Treatment of Technetium in the Vadose Zone at the Hanford Site Central Plateau
Technetium-99 (Tc-99) is present in the vadose zone of the Hanford Central Plateau and is a concern with respect to the protection of groundwater. The persistence, limited natural attenuation mechanisms, and geochemical behavior of Tc-99 in oxic vadose zone environments must be considered in developing effective alternatives for remediation. This report describes a new in situ geochemical manipulation technique for decreasing Tc-99 mobility using a combination of geochemical Tc-99 reduction with hydrogen sulfide gas and induced sediment mineral dissolution with ammonia vapor, which create conditions for deposition of stable precipitates that decrease the mobility of Tc-99. Laboratory experiments were conducted to examine changes in Tc-99 mobility in vadose zone sediment samples to evaluate the effectiveness of the treatment under a variety of operational and sediment conditions.
- Publication Date:
- OSTI Identifier:
- Report Number(s):
- PNNL--23665; RPT-DVZ-AFRI--023
- DOE Contract Number:
- Resource Type:
- Technical Report
- Research Org:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Org:
- Country of Publication:
- United States
- 58 GEOSCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY technetium; vadose zone; remediation
Enter terms in the toolbar above to search the full text of this document for pages containing specific keywords.