Martin Dangelmayr, Cullen Meurer, Aaron Tigar, Raymond H. Johnson, Charles Paradis
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引用次数: 0
Abstract
Elevated uranium concentrations in groundwater remain a persistent challenge at contaminated sites. Several sites rely on natural flushing of uranium as a remediation strategy. Uncertainties in conceptual models can cause remediation strategies to underestimate timeframes required to reach remediation goals. In this study, laboratory experiments were conducted to investigate uranium flushing of sediments from a site with persistent groundwater contamination. Six columns were used to simulate alkalinity-enhanced flushing of uranium from sediments, by switching influent alkalinity after ~12 pore volumes. About 20% to 31% of sediment uranium was consistently flushed from the sediments. Kd values varied greatly (5.3 to 117 L/kg) but were consistently lower (20% to 50%) during influents with elevated alkalinity. The mass of uranium recovered from the columns also was consistently higher (5% to 80%) during alkalinity-enhanced flushing periods. However, column experiments with sequentially increasing alkalinity showed diminishing returns in uranium elution at higher carbonate concentrations. The loss of flushing efficiency is attributed to significant calcite precipitation at higher alkalinities. The results show that alkalinity-enhanced flushing of uranium could be employed as a viable remediation scheme if calcite precipitation could be minimized in a field application.
期刊介绍:
Since its inception in 1981, Groundwater Monitoring & Remediation® has been a resource for researchers and practitioners in the field. It is a quarterly journal that offers the best in application oriented, peer-reviewed papers together with insightful articles from the practitioner''s perspective. Each issue features papers containing cutting-edge information on treatment technology, columns by industry experts, news briefs, and equipment news. GWMR plays a unique role in advancing the practice of the groundwater monitoring and remediation field by providing forward-thinking research with practical solutions.