Collaborative Research: Enhanced Biogeochemical Flushing of Uranium in Groundwater

合作研究：地下水中铀的强化生物地球化学冲洗

• 批准号: 2229869
• 负责人: Charles Paradis
• 金额: $ 35万
• 依托单位: University of Wisconsin-Milwaukee
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2229869&HistoricalAwards=false
• 关键词: Collaborative; Research; Enhanced; Biogeochemical; Flushing

Approximately 115 million people in the United States use groundwater as source of drinking water. Many groundwater aquifers are contaminated with uranium from both natural and anthropogenic sources. Prior to its usage as source of drinking water, uranium contaminated groundwater needs to be treated to achieve a target concentration below the EPA MCL (Maximum Concentration Limit) of 30 micrograms per liter (µg/L). In-situ immobilization is currently the leading remediation technology for uranium-contaminated aquifers. This approach relies on the manipulation of the redox biogeochemistry of uranium to reduce and convert mobile uranyl [U(VI)] ions to the mineral uraninite (UO2) which is generally considered immobile in uranium-contaminated aquifers. However, uraninite is highly susceptible to re-oxidation and re-mobilization by oxidants such as oxygen, thus limiting the efficacy of in-situ immobilization as a remediation technology. The goal of this project is to investigate the enhanced biogeochemical mobilization and flushing of uranium from contaminated aquifers as an alternative remediation technology. To advance this goal, the Principal Investigators (PIs) propose to carry out an integrated research program with field, laboratory, and modeling studies to characterize and unravel the biogeochemical reactions and microbial processes that control uranium mobilization in contaminated aquifers. The successful completion of this research will benefit society through the generation of new fundamental knowledge, data and validated models to advance the design and implementation of more efficient and cost-effective remediation technologies for uranium contaminated aquifers. Additional benefits to society will be accomplished through education and outreach including the mentoring of one graduate student and one post-doctoral scholar at the University of Wisconsin-Milwaukee and one graduate student at the University of Wisconsin-Madison.The remediation of uranium-contaminated aquifers has been largely focused on immobilizing uranium by stimulating the abiotic and biotic processes and reactions that control the reduction and conversion of soluble and mobile uranyl [U(VI)] ions to stable and immobile uraninite minerals. However, in situ immobilization has limited effectiveness and the estimated times to naturally flush uranium to below the EPA MCL often exceed hundreds of years. The overarching goal of this research is to understand how to better tune and manipulate the biogeochemical processes and reactions that control the mobility of uranium in contaminated aquifers with the aim of enhancing uranium mobilization and flushing from these aquifers through the injection of oxygen and bicarbonate enriched surface water. The specific objectives of the research are to: 1) Characterize and unravel the biogeochemical mechanisms of uranium mobilization using geochemical modeling and available thermodynamic and kinetic reaction data, 2) Conduct laboratory experiments to investigate the effect of microbial activity on the mobility of uranium under oxygen- and carbonate-rich conditions, and 3) Determine flow and reactive transport parameters to support the implementation and validation of a uranium transport/mobilization model using finite difference numerical modeling and available uranium mobilization data from single-well tracer experiments. The successful completion of this project has the potential for transformative impact through the generation of fundamental knowledge and modeling tools to advance the design and implementation of in-situ enhanced mobilization and flushing as an alternative remediation technology for uranium contaminated aquifers. To implement the educational and outreach goals of this project, the Principal Investigators (PIs) propose to integrate the findings from this research into an existing course at the University of Wisconsin-Madison. In addition, the PIs plan to leverage existing programs at their respective institutions to design and build an exhibition panel on metal contamination in groundwater and aquifers in Wisconsin that will be displayed at the Northern Great Lakes Visitor Center for viewing by Summer 2024.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

美国约有1.15亿人使用地下水作为饮用水来源。许多地下水含水层被天然和人为来源的铀污染。在将其用作饮用水来源之前，需要对铀污染的地下水进行治疗，以达到低于EPA MCL（最大浓度极限）的目标浓度每升30微克（µg/L）。目前，原位固定化是铀污染含水层的领先补救技术。这种方法依赖于对铀的氧化还原生物地球化学的操纵，以减少和转化流动铀酰[U（VI）]离子为矿物铀元石（UO2），通常认为这在铀污染的含水层中通常被认为是不动的。然而，铀素非常容易受到氧化物（例如氧）的重新氧化和重新化学化，因此将原位固定化的效率限制为一种补救技术。该项目的目的是调查增强的生物地球化学动员和从受污染的含水层作为替代补救技术中铀的冲洗。为了促进这一目标，首席研究人员（PIS）提出的提案旨在通过现场，实验室和建模研究进行综合研究计划，以表征和揭示控制受污染的含水层中铀动员的生物地球化学反应和微生物过程。这项研究的成功完成将通过产生新的基本知识，数据和经过验证的模型来使社会受益，从而推动为铀污染的含水仪的设计和实施更有效，更具成本效益的补救技术。威斯康星大学 - 米尔沃基大学的一名研究生和一名博士后科学的心理以及一名威斯康星大学 - 麦迪逊大学的一名研究生将通过教育和外展览来实现对社会的额外好处，包括对铀污染物的补救措施的修复。以及移动的铀酰[U（VI）]离子，可构成稳定和固定的铀矿矿物质。但是，原位固定的有效性有限，并且估计的时间自然将铀冲洗至EPA MCL以下通常超过数百年。这项研究的总体目的是了解如何更好地调整和操纵控制受污染的含水层中铀的生物地球化学过程和反应，以通过注入氧气和碳酸氢盐富含的地表水从这些含水层增强铀动员并从这些含水层进行冲洗。研究的具体目的是：1）使用地球化学模型以及可用的热力学和动力学反应数据表征和阐明铀动员的生物地球化学机制，2）进行实验室实验，以研究微生物活性对氧气和碳酸盐条件下的氧化和碳酸含量的效果的影响，并确定脉络脉络的影响，并确定脉冲及3次脉络脉络的效果，并确定脉络脉络的效果，并确定脉络脉络的效果，并确定脉络脉的效果。使用有限差异数值建模和单孔示踪剂实验的可用铀动员数据的传输/动员模型。该项目的成功完成通过产生基本知识和建模工具，可以推动现场的增强动员和冲洗作为铀污染的含水层的替代补救技术，从而产生变革性的影响。为了实施该项目的教育和外展目标，首席研究人员（PIS）的提议将这项研究的发现纳入威斯康星大学麦迪逊分校的现有课程。此外，PIS计划利用各自机构的现有计划设计和建立威斯康星州地下水和含水层金属污染的展览小组，该小组将在北部大湖游客中心展示，以在2024年夏季访问中心进行观看。该奖项在2024年夏季颁奖典礼。该奖项反映了NSF的法定任务，反映了通过评估构成的知识群体的支持者，并概述了基金会的支持。