SusChem: Collaborative Research: Role of Biofilms in Engineered Infiltration Systems in the Removal of Bacteria in Urban Stormwater

1511915（陈）1511941（李）城市化导致地表面积显著增加，这阻止了雨水渗入地下并补充地下水。相反，雨水作为地表径流积累，可能导致河床侵蚀和洪水事件。径流还可以带走污染物（例如，病原体），最终进入并污染自然水生系统。本研究的一个重要组成部分是调查雨水化学和干燥期长度的变化对生物膜的化学性质和微生物多样性以及生物膜效率的影响。本研究首次系统地研究了在工程渗滤系统中与环境相关的条件下生长的生物膜对生物膜的影响，从雨水中去除细菌。在各种环境条件下生长的多孔介质中的生物膜的结构，分布和微生物多样性的变化将首次通过共聚焦激光扫描显微镜和高通量测序揭示。使用原子力显微镜测量细菌胶体探针和生物膜之间的界面力将揭示各种生物膜结构将如何影响细菌和生物膜改性表面之间的界面相互作用以及细菌粘附到生物膜的倾向。通过耦合孔隙尺度和连续尺度模拟，这项工作将定量地联系起来的影响，生物膜上的孔隙尺度的流体动力学与细菌的传输和附着率在连续尺度。这项研究将提供新的见解过滤过程中的细菌保留的机制，以及在生物膜改性工程渗透系统排水过程中的细菌的再动员。这项研究是变革性的，因为它揭示了环境条件，物理化学性质和生物膜的微生物多样性，以及细菌-生物膜相互作用之间的复杂关系，这将与环境，化学和生物医学工程领域有关。具体任务包括：1）在微流体细胞中在环境相关条件下生长的生物膜的表征; 2）使用原子力显微镜探测细菌-生物膜相互作用; 3）包括在环境相关条件下生长的生物膜的柱过滤实验;以及4）工程化渗透系统中流体动力学和细菌去除的孔和连续尺度建模。研究结果也将纳入本科和研究生课程材料，并进一步扩大了参与的PI和他们的研究生在组织科学活动的三到五年级的学生在主要是非洲裔美国人的小学/中学在内城巴尔的摩。还将为内布拉斯加州EPSCoR的内布拉斯加州青年科学家夏令营开发关于雨水再利用相关主题的短期课程，这些夏令营由K-12学生参加，其中很大一部分是代表性不足的少数民族。

1511915(Chen) & 1511941(Li)Urbanization has resulted in a significant increase in surfaces which prevent stormwater from infiltrating the subsurface and recharging the groundwater. Instead, stormwater accumulates as surface runoff that can result in streambed erosion and flooding events. The runoff can also pick up contaminants (e.g., pathogens) from the surfaces, which eventually enter and contaminate natural aquatic systems. An important component of this research is to investigate the influence of variation in stormwater chemistry and length of drying periods on the chemical properties and microbial diversity of the biofilms and the efficiency of biofilm-modified engineered infiltration systems to remove bacteria during a storm event.This research is the first to systematically study the effects of biofilms grown under environmentally relevant conditions in engineered infiltration systems on the removal of bacteria from stormwater. The changes in the structure, distribution, and microbial diversity of biofilms in porous media grown under a variety of environmental conditions will be revealed for the first time through confocal laser scanning microscopy and high throughput sequencing. The use of atomic force microscopy for the measurements of interfacial forces between a bacterial colloid probe and biofilms will shed light on how a variety of biofilm structures will influence the interfacial interactions between bacteria and biofilm-modified surfaces and the propensity for bacteria to adhere to biofilms. By coupling pore scale and continuous scale modeling, this work will quantitatively link the influence of biofilms on pore scale hydrodynamics with the rate of bacteria transport and attachment at continuum scale. This research will provide new insights on the mechanisms for bacterial retention during filtration, as well as the remobilization of bacteria during draining in biofilm-modified engineered infiltration systems. This research is transformative because it reveals the intricate relationship between environmental conditions, physicochemical properties and microbial diversity of biofilms, and bacteria-biofilm interactions, which will be relevant to the fields of environmental, chemical, and biomedical engineering. The specific tasks include: 1) characterization of biofilms grown under environmentally relevant conditions in microfluidic cells; 2) probing bacterium-biofilm interactions using atomic force microscopy; 3) column filtration experiments including biofilms grown under environmentally relevant conditions; and 4) pore- and continuum-scale modeling of hydrodynamics and bacterial removal in engineered infiltration systems. Research findings will also be incorporated into undergraduate and graduate course materials and further augmented by the involvement of the PIs and their graduate students in organizing scientific activities for third through fifth-grade students in predominantly African American elementary/middle schools in inner-city Baltimore. Short courses on stormwater reuse-related topics will also be developed for the Nebraska EPSCoR's Young Nebraska Scientists summer camps which are attended by K-12 students, a large fraction of them to be underrepresented minorities.