ERI: Engineering safer rainwater harvesting systems: Relating viable Legionella concentrations to system design and environmental characteristics

该奖项全部或部分由2021年美国救援计划法案（公法117-2）资助。由于气候变化导致降水模式发生变化，因此迫切需要在干旱易发地区增加饮用水和非饮用水水源，并减少更容易受到强降水影响的地区的雨水径流。 雨水收集已成为一种有前途的可持续技术，可满足这两种需求。收集雨水涉及收集和储存雨水，用于随后的用途，如景观灌溉，车辆清洗和厕所/小便池冲洗。经过适当的处理，收集的雨水也可以用于饮用水，包括饮用，烹饪和洗澡。然而，对于饮用水，雨水必须经过处理，以消除对人类健康的风险，包括完全去除军团菌，这是一种在世界各地收集的雨水中检测到的水媒病原体。该项目的总体目标是推进实施一种新的、更有效的检测方法，用于检测和量化收集的雨水中有害军团菌的存在。为了推进这一目标，该项目的主要研究者将探索使用单叠氮乙锭定量聚合酶链反应（EMA-qPCR）作为一种新的和有前途的检测方法，可以准确地量化收集的雨水中活的和有害的军团菌的浓度。该项目的成功完成将通过收集新数据和发展基本知识来造福社会，以防止在将收集的雨水用于饮用和非饮用用途时接触有害的军团菌。通过学生教育和培训，包括对朗伍德大学两名本科生的指导，将进一步造福社会。军团菌是一种水传播的病原体，如果被吸入人体，会导致严重的疾病。 军团菌已在世界各地的雨水收集系统（RWHS）中检测到。基于培养的方法不能检测到活的但不可培养的细胞，因此它们往往低估了水样中存在的有害军团菌细胞的浓度。诸如qPCR的分子方法不能区分活细胞、活细胞和死细胞，因此它们往往会高估水样中有害军团菌的浓度。该ERI项目的目标是推进一种有前途的新技术（叠氮乙锭定量聚合酶链反应或EMA-qPCR）的实施，该技术可以更准确地估计收集的雨水中活菌和有害军团菌的浓度。为了推进这一目标，主要研究者将在50个RWHS进行使用点采样，并测量军团菌属（包括有害军团菌）的浓度。使用包括基于细胞培养的测定、qPCR、基于酶的测定（Legiolert™）和EMA-qPCR的四种方法对嗜肺菌进行鉴定。该项目的成功完成有可能产生变革性影响，因为它提供了数据，支持对与收集的雨水的饮用和非饮用用途有关的人类健康风险进行新的和更准确的估计。 从这个项目中获得的基本知识也可以使工程师和社区设计，建造和部署更有效和更安全的RWHS，以增加饮用水和非饮用水的来源，同时减少由于雨水径流造成的地表水和地下水污染。这个奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).As precipitation patterns change due to climate change, there is a critical need to augment potable and non-potable water sources in drought prone areas and reduce stormwater runoff in areas more susceptible to heavy precipitation. Rainwater harvesting has emerged as a promising and sustainable technology to address both of those needs. Harvesting rainwater involves the collection and storage of rain for subsequent usages such as landscape irrigation, vehicle washing, and toilet/urinal flushing. With the appropriate treatment, harvested rainwater could also be utilized for potable needs including drinking, cooking, and bathing. However, for potable usage, rainwater must be treated to eliminate risks to human health including the complete removal of Legionella, a waterborne pathogen that has been detected in harvested rainwater worldwide. The overarching goal of this project is to advance the implementation of a novel and more effective assay for detecting and quantifying the presence of harmful Legionella bacteria in harvested rainwater. To advance this goal, the Principal Investigator of this project will explore the use of ethidium monoazide quantitative polymerase chain reaction (EMA-qPCR) as a new and promising assay that could accurately quantify the concentrations of viable and harmful Legionella bacteria in harvested rainwater. The successful completion of this project will benefit society through the collection of new data and development of fundamental knowledge to prevent exposure to harmful Legionella bacteria when using harvested rainwater for potable and non-potable applications. Further benefits to society will be achieved through student education and training including the mentoring of two undergraduate students at Longwood University. Legionella is a waterborne pathogen, if inhaled, can cause severe illness in humans. Legionella bacteria have been detected in rainwater harvesting systems (RWHS) worldwide. Culture-based methods cannot detect viable but non-culturable cells and thus they tend to underestimate the concentration of harmful Legionella cells present in a water sample. Molecular methods such as qPCR cannot distinguish between living, viable, and dead cells and consequently they tend to overestimate the concentration of harmful Legionella bacteria in a water sample. The goal of this ERI project is to advance the implementation of a promising new technique (ethidium monoazide quantitative polymerase chain reaction or EMA-qPCR) that could lead to more accurate estimates of the concentration of viable and harmful Legionella bacteria in harvested rainwater. To advance this goal, the Principal Investigator will conduct point-of-use sampling at 50 RWHS and measure the concentrations of Legionella bacterial species including harmful L. pneumophila bacteria using four methods including a cell culture-based assay, qPCR, an enzyme-based assay (Legiolert™), and EMA-qPCR. The successful completion of this project has the potential for transformative impact by providing data to support new and more accurate estimates of human health risks associated with the potable and non-potable usages of harvested rainwater. The fundamental knowledge gained from this project could also enable engineers and communities to design, build, and deploy more effective and safer RWHS to augment potable and non-potable sources of water while reducing surface and groundwater pollution due to stormwater runoff.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.