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

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公共法律117-2)。随着气候变化导致降水模式发生变化，迫切需要在干旱易发地区增加饮用水和非饮用水水源，并在更容易出现强降水的地区减少雨水径流。雨水收集已经成为一种有前途的可持续技术，可以满足这两种需求。收集雨水涉及收集和储存雨水，以供后续使用，如景观灌溉、洗车和冲厕所/小便池。通过适当的处理，收集的雨水还可以用于饮用水需求，包括饮用水、烹饪和洗澡。然而，对于饮用水，必须对雨水进行处理，以消除对人类健康的风险，包括完全清除军团菌，这是一种在世界各地收集的雨水中检测到的水媒病原体。该项目的首要目标是推动实施一种新的、更有效的检测和量化收集的雨水中有害军团菌存在的方法。为了推进这一目标，该项目的首席研究员将探索使用单叠氮乙锭定量聚合酶链式反应(EMA-qPCR)作为一种新的和有前途的分析方法，可以准确地定量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使社会受益，方法是收集新的数据和发展基本知识，以防止在将收集的雨水用于饮用水和非饮用水时接触有害的军团菌细菌。将通过学生教育和培训，包括指导朗伍德大学的两名本科生，为社会带来进一步的好处。军团菌是一种水传播的病原体，如果被吸入，可导致人类严重疾病。在世界各地的雨水收集系统(RWHS)中都发现了军团菌。以培养为基础的方法无法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。定量聚合酶链式反应等分子方法不能区分活细胞、活细胞和死亡细胞，因此它们往往高估了水样中有害军团菌的浓度。这一ERI项目的目标是推进一项有前景的新技术(单叠氮乙锭定量聚合酶链式反应或EMA-qPCR)的实施，该技术可以更准确地估计收集的雨水中可存活和有害的军团菌的浓度。为实现这一目标，首席调查员将在50RWHS进行使用点抽样，并使用四种方法测量军团菌细菌种类的浓度，包括基于细胞培养的分析、定量聚合酶链式反应、基于酶的分析(军团菌™)和EMA-定量聚合酶链式反应。这一项目的成功完成有可能产生变革性的影响，因为它提供了数据，以支持对与收集的雨水的饮用和非饮用有关的人类健康风险的新的和更准确的估计。从这个项目中获得的基本知识还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水源，同时减少雨水径流造成的地表和地下水污染。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。

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.