In-Situ Uranium Stabilization Through Polyphosphate Injection: Pilot-Scale Treatability Test at the 300 Area, Hanford Site
- Pacific Northwest National Laboratory, Richland, WA (United States)
This paper describes the pilot-scale treatability test that was conducted to evaluate the efficacy of using a polyphosphate injection approach to treat uranium-contaminated groundwater in situ within the 300 Area aquifer at the Hanford Site in Richland, Washington. Primary test objectives were to assess 1) direct treatment of available uranium contributing to the groundwater plume through precipitation of the uranyl-phosphate mineral autunite, and 2) emplacement of secondary-treatment capacity via precipitation of the calcium-phosphate mineral apatite, which acts as a long-term sorbent for uranium. Based on an injection design analysis that incorporated results from both bench-scale testing and site-specific characterization activities, a three-phase injection approach was selected for field-scale testing. This approach consisted of 1) an initial polyphosphate injection to facilitate direct treatment of aqueous uranium in the pore space, 2) a second phase consisting of a calcium chloride injection to provide an available calcium source for the creation of apatite, and 3) a subsequent polyphosphate injection to supply a phosphate source for the formation of apatite. The total-solution volume injected during this field test was approximately 3.8 million L (1 million gal). Results from this investigation will be used to identify implementation challenges and investigate the technology's ability to meet remedial objectives. In addition, data from this test will provide valuable information for designing a full-scale remedial action for uranium in groundwater beneath the 300 Area of the Hanford Site, and a detailed understanding of the fundamental underpinnings necessary to evaluate the efficacy and potential for utilization of the polyphosphate technology at other sites with varying geochemical and hydrodynamic conditions. (authors)
- Research Organization:
- WM Symposia, 1628 E. Southern Avenue, Suite 9 - 332, Tempe, AZ 85282 (United States)
- OSTI ID:
- 21319755
- Report Number(s):
- INIS-US-10-WM-08187; TRN: US10V0446061946
- Resource Relation:
- Conference: 2008 Waste Management Symposium - WM2008/WM'08: HLW, TRU, LLW/ILW, Mixed, Hazardous Wastes and Environmental Management - Phoenix Rising: Moving Forward in Waste Management, Phoenix, AZ (United States), 24-28 Feb 2008; Other Information: Country of input: France; 13 refs
- Country of Publication:
- United States
- Language:
- English
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