干旱区生态环境知识资源中心(Arid): Sequestration of Sr-90 Subsurface Contamination in the Hanford 100-N Area by Surface Infiltration of a Ca-Citrate-Phosphate Solution

Arid

DOI	10.2172/985589
报告编号	PNNL-18303
来源ID	OSTI_ID: 985589
	Sequestration of Sr-90 Subsurface Contamination in the Hanford 100-N Area by Surface Infiltration of a Ca-Citrate-Phosphate Solution
	Szecsody, James E.; Rockhold, Mark L.; Oostrom, Martinus; Moore, R. C.; Burns, Carolyn A.; Williams, Mark D.; Zhong, Lirong; Fruchter, Jonathan S.; McKinley, James P.; Vermeul, Vincent R.; Covert, Matthew A.; Wietsma, Thomas W.; Breshears, Andrew T.; Garcia, Ben J.
英文摘要	The objective of this project is to develop a method to emplace apatite precipitate in the 100N vadose zone, which results in sorption and ultimately incorporation of Sr-90 into the apatite structure. The Ca-citrate-PO4 solution can be infiltrated into unsaturated sediments to result in apatite precipitate to provide effective treatment of Sr-90 contamination. Microbial redistribution during solution infiltration and a high rate of citrate biodegradation for river water microbes (water used for solution infiltration) results in a relatively even spatial distribution of the citrate biodegradation rate and ultimately apatite precipitate in the sediment. Manipulation of the Ca-citrate-PO4 solution infiltration strategy can be used to result in apatite precipitate in the lower half of the vadose zone (where most of the Sr-90 is located) and within low-K layers (which are hypothesized to have higher Sr-90 concentrations). The most effective infiltration strategy to precipitate apatite at depth (and with sufficient lateral spread) was to infiltrate a high concentration solution (6 mM Ca, 15 mM citrate, 60 mM PO4) at a rapid rate (near ponded conditions), followed by rapid, then slow water infiltration. Repeated infiltration events, with sufficient time between events to allow water drainage in the sediment profile can be used to buildup the mass of apatite precipitate at greater depth. Low-K heterogeneities were effectively treated, as the higher residual water content maintained in these zones resulted in higher apatite precipitate concentration. High-K zones did not receive sufficient treatment by infiltration, although an alternative strategy of air/surfactant (foam) was demonstrated effective for targeting high-K zones. The flow rate manipulation used in this study to treat specific depths and heterogeneities are not as easy to implement at field scale due to the lack of characterization of heterogeneities and difficulty tracking the wetting front over a large subsurface area. However, the use of real-time surface and cross-borehole geophysics can be used to track the infiltrating Ca-citrate-PO4 front so some adjustments can be made in the infiltration rate to precipitate apatite in desired zones. In addition, the reactive transport code used in this study with field scale physical parameters for sediments can be used to evaluate infiltration strategies along with preliminary water infiltration tests at field scale.
出版年	2009
报告类型	Technical Report
语种	英语
国家	美国
来源学科分类	58 GEOSCIENCES ; APATITES ; BIODEGRADATION ; BUILDUP ; CITRATES ; CONTAMINATION ; DRAINAGE ; FLOW RATE ; GEOPHYSICS ; RIVERS ; SEDIMENTS ; SORPTION ; SPATIAL DISTRIBUTION ; TRANSPORT ; WATER ; WATER INFLUX Sr-90 in sediments, Hanford 100N, Ca-citrate-PO4 infiltration, remediation ; Environmental Molecular Sciences Laboratory
URL	http://www.osti.gov/scitech/servlets/purl/985589
资源类型	科技报告
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/269778
推荐引用方式 GB/T 7714	Szecsody, James E.,Rockhold, Mark L.,Oostrom, Martinus,et al. Sequestration of Sr-90 Subsurface Contamination in the Hanford 100-N Area by Surface Infiltration of a Ca-Citrate-Phosphate Solution,2009.