Coupling of physical and bio-geochemical processes in saturated and unsaturated subsurface systems.

饱和和不饱和地下系统中物理和生物地球化学过程的耦合。

• 批准号: RGPIN-2014-06610
• 负责人: Amos, Richard
• 金额: $ 2.7万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=612326
• 关键词: Coupling; physical; bio; geochemical; processes

The contamination of groundwater from mining, industrial and other anthropogenic activities threatens potable water supplies and ecosystem health. The transport and fate of contaminants in groundwater and in unsaturated soils often involves complex biogeochemical reactions coupled to physical transport and attenuation processes. Reactive transport models provide a means of quantifying these processes, providing a means of analyzing complex data sets and providing insights into the underlying mechanisms of contaminant transport and attenuation. The long-term objectives of the research are to better understand and quantify coupled biogeochemical and physical processes, and the effect of this coupling on contaminant transport and attenuation, through the development of reactive transport models. The key areas for development will include: 1) Simulation of nano-particle and colloid transport and reactivity: Colloids are particles with dimensions measuring in the nano-meter scale. Inorganic and organic colloids can interact with metal-bearing wastes and potentially facilitate their transport in the environment. A reactive transport model will be developed to simulate colloid transport and geochemical interactions, and the model will be used to simulate field and laboratory column experiments to gain a better understanding of colloid-associated metal transport. 2) Simulation of stable isotope fractionation in multi-phase systems: A reactive transport model will be developed to simulate the fractionation of carbon isotopes in methane and carbon in dissolved and vapour phase gases, including gas bubbles. The model will be used to simulate the degradation of contaminants at an oil spill site near the town of Bemidji, MN, providing a better understanding of degradation rates, and transport and attenuation mechanisms. In addition, laboratory tank experiments will be conducted to better quantify the gas/water interactions at the water table. 3) Coupling of physical and geochemical processes in mine waste: The prediction of drainage quality from waste-rock piles is an important aspect of mine planning and permitting. A reactive transport model will be developed to couple thermal, hydrological and geochemical interactions in waste-rock dumps. The model will be applied to data collected at the Diavik Diamond Mine in the Northwest Territories to better understand the processes controlling water quality. 4) Mechanistic simulation of gases and gas bubble movement in contaminated aquifers. A reactive transport model will be developed to provide a better description of gas transport, including the movement of gas bubbles in groundwater. The model will be used to simulate 1) the transport of volatile organic contaminants in groundwater including the vertical transport of gas bubbles due to buoyancy, 2) tritium and organic contaminants in unsaturated materials below and low-level nuclear waste repository, and 3) the entrapment of gas bubbled during recharge below an artificial recharge pond. The proposed research will provide a unique reactive transport model that will provide insight into the movement of contaminants in the subsurface. This insight will aid in the development of cost-effective contaminant stabilization and remediation options that will assist Canadian industry in meeting environmental protection standards. The research will train highly qualified personnel in the development and application of numerical models and provide them with a thorough understanding of contaminant geochemistry and remediation science. These trainees will continue with cutting edge research or will work in industry, managing contamination issues and helping to maintain Canadian companies at the leading edge of the contaminant remediation industry.

采矿、工业和其他人为活动对地下水的污染威胁着饮用水供应和生态系统的健康。地下水和非饱和土壤中污染物的迁移和归宿往往涉及复杂的生物地球化学反应，以及物理迁移和衰减过程。反应输运模型提供了一种量化这些过程的方法，提供了一种分析复杂数据集的方法，并提供了对污染物输运和衰减的潜在机制的见解。研究的长期目标是通过发展反应输运模型，更好地理解和量化耦合的生物地球化学和物理过程，以及这种耦合对污染物输运和衰减的影响。发展的主要领域将包括：