CAREER: Multiscale Bacterial Transport in Porous Media

控制土壤中的细菌传播可以帮助防止病原体在地下水中的传播，通过对土壤微生物群的作用来促进可持续农业，并有助于清理环境污染物。然而，现有关于细菌与周围流体和表面之间相互作用的知识不足以解释它们的运输，即使在简单的封闭结构中也是如此。该奖项将通过以米为尺度量化细菌从微孔到距离的传输，并通过考虑细菌与复杂流动环境之间的相互作用来模拟它们的运动，从而克服现有的限制。这项研究将告诉我们未来通过设计多孔介质和控制水流来预测和调整细菌传输的能力。该项目包括一个综合教育计划，使用显微镜、土壤微生物群和水等主题来增加STEM的代表性，并培养成功的研究生。该计划将带来实践活动和公共科学讲座，以培养家庭对科学的兴趣。这些活动将在服务不足社区的学校和公共场所以英语和西班牙语提供。为了建立一个定量的理解来预测和控制细菌在土壤中的传输，这个项目将通过实验和计算探索颗粒和孔隙尺度的物理相互作用、细菌活动和化学梯度如何影响多孔介质中游泳细菌在尺度上的传输。该项目将：(1)首次利用为此目的建造的独特设备，以简单的几何形状量化基本的传输大小，如细菌在尺度上和下游覆盖的距离和时间；(2)开发一种计算描述，说明在高限制条件下溶剂的波动速度场；以及(3)根据流动、介质的统计特性和化学引诱剂的效果，对复杂多孔介质中的尺度间的传输进行量化和建模。这项研究的结果有助于设计和优化污染控制和废水处理的生物过滤系统，并为分离细菌、影响生物技术、制药和生物燃料等行业的新方法提供信息。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Controlling bacterial transport in soils could help prevent the spread of pathogens in groundwater, contribute to sustainable agriculture by acting on the soil microbiome, and help clean up environmental pollutants. However, existing knowledge of the interactions between the bacteria and the surrounding fluids and surfaces is insufficient to explain their transport even in simple confining structures. This award will bridge existing limitations by quantifying bacterial transport from microscopic pores to distances in the scale of meters and modeling their motion by accounting for the interactions between the bacteria and the complex flow landscape. The research will inform our future ability to predict and tune bacterial transport by engineering porous media and controlling water flow. The project includes an integrated education program using the topics of microscopes, soil microbiome, and water to increase representation in STEM and educate graduate students for success. The plan will bring hands-on activities and public science talks to cultivate interest in science in families. These activities will be offered in English and Spanish in schools and public places in underserved communities. To create a quantitative understanding to predict and control the transport of bacteria in soils, this project will experimentally and computationally explore how particle and pore-scale physical interactions, bacterial activity, and chemical gradients affect the transport of swimming bacteria across scales in porous media. The project will: (1) quantify for the first time fundamental magnitudes of transport, like the distances and times covered by bacteria upstream and downstream across scales in simple geometries, using unique equipment built for this purpose; (2) develop a computational description that accounts for the solvent’s fluctuating velocity field under high confinement; and (3) quantify and model the transport across scales in complex porous media as a function of the flow, statistical properties of the medium, and the effect of chemoattractants. Results from this research can contribute to designing and optimizing biofiltration systems for pollution control and wastewater treatment, and it could inform new ways of separating bacteria, impacting industries like biotechnology, pharmaceuticals, and biofuels.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.