Collaborative Research: Virus removal in membrane bioreactors: Role of virus aggregation and adhesion

1236672/1236393 Nguyen/Tarabara好氧膜生物反应器(MBR)已成为处理城市和工业废水的最先进技术。与传统的活性污泥法相比，膜生物反应器具有占地面积小、出水水质好等优点。MBR已成为一种特别有吸引力的水回用处理选择。在再利用应用中，或当污水被排放到娱乐用水等敏感水体时，尤其重要的是清除病毒病原体，以使公众健康不受威胁。目前缺乏对MBR中病毒去向的全面研究，但需要更广泛地应用MBR技术，包括分散的可变进水水质的水回用。PIS将系统地研究MBR中病毒黏附和聚集在病毒去除中的作用。中心假设是病毒对胞外聚合物(EPS)和可溶性微生物产物(SMP)的黏附程度与病毒通过细胞膜的程度相反。实验计划包括以下任务：(1)采用不同孔径的平板膜和中空纤维膜进行好氧膜生物反应器的小试研究；在一组测试中，操作条件将模拟密歇根州特拉弗斯城CH2M Hill全尺寸MBR设施中使用的操作条件，(2)表征从小规模MBR系统和全规模MBR工厂获得的SMP、EPS和膜生物膜，(3)使用任务2中描述的SMP和EPS来量化病毒聚集和与污染膜的黏附，(4)在生物膜发展的不同阶段，黏附和聚集与污染膜去除病毒的相关性，以及(5)使用细胞培养依赖的方法和定量PCR来评估MBR中病毒的去除。腺病毒被选为本研究的靶病毒。这些发现将有可能改变MBR的设计标准，特别是当它们与膜选择有关时。虽然基于膜生物反应器的治疗依赖于膜来确保适当的分离屏障，但病毒去除并不是设计膜生物反应器的标准。随着我们对水的技术、经济和社会态度和方法从单向的资源到废物的方法转变为可持续再利用的概念，对处理过的旧水的微生物质量进行更严格的控制成为一个何时而不是是否的问题。考虑到这一点，我们看到了我们提出的研究的实际目的，即为制定不久的将来的水再利用政策和法规所需的决策过程提供信息。该项目的成功完成将为重新构思MBR的设计和运行提供科学基础，以适应病毒去除作为设计标准和治疗目标之一。该项目汇集了一个多元化的PI团队，他们拥有包括界面科学、膜工艺和环境微生物学在内的一系列免费技能，以及一个代表全面MBR设施的工业合作伙伴。在所有私人投资机构的共同指导下，一批研究生和本科生将在一个结合学术研究、与工业界合作的实验室研究和国际工作的环境中获得一系列学习机会。PIS将在UIUC(1年级)、MSU(2年级)和Traverse City MBR设施(3年级)组织年度小型研讨会，项目参与者将在这些研讨会上展示他们的发现，讨论未来的研究并听取行业合作伙伴的反馈。

1236672/1236393Nguyen/Tarabara Aerobic membrane bioreactors (MBRs) have become a state-of-the-art technology for municipal and industrial wastewater treatment. Compared to traditional activated sludge reactors, advantages of MBR include smaller footprint and better effluent quality. MBRs have become a particularly attractive treatment choice for water reuse. In reuse applications or when the effluent is released to sensitive water bodies such as recreational water, it is especially important that viral pathogens are removed so that public health is not threatened. Comprehensive studies of virus fate in MBRs are currently lacking yet required for wider application of MBR technology, including decentralized water reuse with variable influent quality. The PIs will systematically investigate the role of virus adhesion and aggregation on virus removal in MBRs. The central hypothesis is that the extent of virus adhesion to extracellular polymeric substances (EPS) and soluble microbial products (SMP) counter-correlates with virus passage through the membrane. The experimental plan consists of the following tasks: (1) conduct bench-scale aerobic MBR studies with flat sheet and hollow fiber membranes of varied pore size; in a subset of tests operating conditions will mimic those used in the CH2M Hill full-scale MBR facility in Traverse City, MI, (2) characterize SMP, EPS, and membrane biofilm harvested from the bench-scale MBR system and the full-scale MBR plant, (3) quantify virus aggregation and adhesion to fouled membranes using SMP and EPS characterized in Task 2, (4) correlate adhesion and aggregation with the removal of virus by fouled membranes at different stages of biofilm development, and (5) evaluate virus removal in MBRs using cell culture-dependent methods and quantitative PCR. Adenovirus is selected as target virus for this study. The findings will have the potential for transforming MBR design criteria particularly as they pertain to membrane selection. While MBR-based treatment relies on the membrane to ensure an appropriate separation barrier, virus removal has not been a criterion in designing MBRs. As our technological, economic and social attitudes and approaches toward water shift from the unidirectional resource-to-waste approach toward the concept of sustainable reuse, stricter control over microbiological quality of treated used water becomes a question of when rather than if. With this in mind, we see the practical end of the research we propose in informing the decision-making process required for the development of water reuse policies and regulations of the near future. Successful completion of this project will provide scientific basis for re-conceptualizing MBR design and operation to accommodate virus removal as one of design criteria and treatment goals. The project brings together a diverse team of PIs with a complimentary set of skills including interfacial science, membrane processes, and environmental microbiology and an industrial partner representing a full-scale MBR facility. A group of graduate and undergraduate students co-advised by all PIs will be provided a range of learning opportunities in an environment that combines academic studies, laboratory research in collaboration with the industrial sector, and international work. The PIs will organize annual mini-symposia - at UIUC (year 1), MSU (year 2), and at the Traverse City MBR facility (year 3) where project participants will present their findings, discuss future research and receive feedback from the industrial partner.