Browsing by Author "Kang, Peter"

Now showing 1 - 5 of 5
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    Banking Groundwater - A study examining aquifer storage and recovery for groundwater sustainability in Minnesota
    Bilotta, John P.; Arnold, William; Kang, Peter; Seonkyoo, Yoon; Shandilya, Raghwendra N.; Bresciani, Etienne; Lee, Seunghak; Kirk, Josh; Levers, Lucia; Bohman, Brian; Kirby, Eileen; Runkel, Anthony; Xiang, Galen; Gassman, Phillip; Valcu-Lisman, Adriana; Jennings, Carrie E.; jbilotta@umn.edu; Bilotta, John P; University of Minnesota Water Resources Center; Freshwater
    Some of the more than 75% of Minnesotans who rely on groundwater may find it in short supply in the face of population, land-use and climate change. Aquifer storage and recovery (ASR) is a technological approach to treat and inject clean water into an aquifer for temporary storage. The hydrogeological characteristics and the chemistry of the source water and aquifer impact treatment needs prior to injection and after extraction. Aquifer properties that control how water moves determine the volume and rate of water injected. This study examined four different kinds of aquifers across Minnesota with unique pressures to determine their suitability for ASR. The study findings suggest three may be suitable for ASR. The Buffalo aquifer in Moorhead has variable injection capacity and multiple sources of water for injection. Water quality issues of arsenic, sulfate, manganese, and hardness would require treatment after extraction. The Jordan aquifer in Rochester faces increased pressure from growth and nitrate contamination in the surrounding agricultural areas. The wastewater treatment plant could provide adequate source water if treated. Woodbury faces pressure from increasing population and PFAS contamination of the Jordan aquifer. ASR could recharge groundwater from wastewater treatment plants and also be integrated with PFAS remediation scenarios by reinjection of treated groundwater. ASR is not recommended for the surficial sand aquifer in the Straight River Groundwater Management area in north central Minnesota because there is no source of water to make it a feasible option at this time. Cost-benefit analysis combined with a sensitivity analysis of economic factors should be a component of ASR project feasibility. Modified state well code and a streamlined permitting path would allow more successful development and deployment of ASR. State adoption of control over Class V injection wells from the USEPA is also necessary.
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    Data and numerical simulation setup for Fluid inertia controls mixing-induced precipitation and clogging in pore to network-scale flows
    (2024-01-16) Yang, Weipeng; Chen, Michael; Lee, Sang; Kang, Peter; yang8782@umn.edu; Yang, Weipeng; University of Minnesota Kang Research Group
    Mixing-induced mineral precipitation, a critical process in both natural and engineering processes, presents complex challenges in terms of control and predictability. The dynamics of precipitation, particularly under the influence of fluid flow, remain poorly understood. Using microfluidic experiments and three-dimensional reactive transport simulations, we demonstrate that fluid inertia controls mineral precipitation and clogging at flow intersections, even in laminar flows. We discern distinct precipitation regimes as a function of Reynolds number: low Reynolds numbers (Re ≤ 10) lead to precipitation shut off, whereas high Reynolds numbers (Re ≥ 50) prompt rapid clogging. Additionally, when injection rates are uneven from two inlets, we observed unexpected flow bifurcation phenomena, which resulted in enhanced concurrent precipitation in both downstream channels. Finally, we extend our findings to rough channel intersections and networks and demonstrate that the identified inertial effects that shape precipitation and clogging at the pore scale are also present and even more dramatic at the network scale. The findings provide a framework for designing and optimizing processes in which precipitation is an essential component, as well as shedding light on the fundamental mechanisms governing mixing-induced mineral precipitation in flow systems.
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    Digitized fracture network data from Bristol Channel Basin, UK
    (2019-03-28) Kang, Peter; pkkang@umn.edu; Kang, Peter
    This is a natural fracture network data generated based on a limestone outcrop located at the southern margin of the Bristol Channel Basin, UK.
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    Microfluidic Experiments and Numerical Simulations of Inertia-induced Mixing and Reaction Maximization in Laminar Porous Media Flows
    (2024-10-10) Chen, Michael; Lee, Sanghyun; Kang, Peter; pkkang@umn.edu; Kang, Peter; Kang Research Group
    Solute transport and biogeochemical reactions in porous and fractured media flows are controlled by mixing, as are subsurface engineering operations such as contaminant remediation, geothermal energy production, and carbon sequestration. A porous media flow is generally regarded as slow, so the effects of fluid inertia on mixing and reaction are typically ignored. Here, we demonstrate through microfluidic experiments and numerical simulations of mixing-induced reaction, that inertial recirculating flows readily emerge in laminar porous media flows and dramatically alter mixing and reaction dynamics. An optimal Reynolds number that maximizes the reaction rate is observed for individual pore throats of different sizes. This reaction maximization is attributed to the effects of recirculation flows on reactant availability, mixing, and reaction completion, which depend on the topology of recirculation relative to the boundary of the reactants or mixing interface. Recirculation enhances mixing and reactant availability, but a further increase in flow velocity reduces the residence time in recirculation, leading to a decrease in reaction rate. The reaction maximization is also confirmed in a flow channel with grain inclusions and a randomized porous media. Interestingly, the domain-wide reaction rate shows a dramatic increase with increasing Re in the randomized porous media case. This is because fluid inertia induces complex three-dimensional flows in a randomized porous media, which significantly increases transverse spreading and mixing. This study shows how inertial flows control reaction dynamics at the pore scale and beyond, thus having major implications for a wide range of environmental systems.
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    Numerical simulation setup for single mineral dissolution in a single pore channel
    (2024-01-04) Lee, Woonghee; Kang, Peter; lee02042@umn.edu; Lee, Woonghee; University of Minnesota Kang Research Group
    We conducted pore-scale numerical simulations for single mineral dissolution for two-dimensional and three-dimensional systems using OpenFOAM. We explored the effects of flow rates on mineral dissolution dynamics.