CAREER: Locally Enhanced Electric Field Treatment (LEEFT) for Chemical-Free Water Disinfection

全世界有8亿多人没有足够的安全饮用水。在饮用水处理厂服务的许多地区，氯被用来杀死有害微生物。然而，氯化可以产生已知的人类致癌物质的化学物质。一项创新技术，可以提供服务点处理没有足够的饮用水供应的地区是局部增强电场处理（LEEFT）。LEEFT在低电压下运行，处理时间短至几秒钟，实现了高度消毒。LEEFT具有相对便宜、不含化学物质、坚固耐用和易于操作的额外好处。在这个项目中，PI将研究如何在LEEFT处理过程中杀死饮用水中的有害微生物。这项工作的目标是开发LEEFT，广泛采用饮用水处理，以保护公众健康。该项目的教育计划侧重于培养未来的环境工程领导者在高中，本科和研究生水平。这一努力将得到公众宣传的补充，以提高人们对水安全的认识，并使公众更好地准备应对因意外自然灾害造成的供水中断。LEEFT是一种物理处理过程，旨在利用强电场破坏细胞膜，从而消灭饮用水中的病原体。安装在LEEFT装置中的电极通常用一维纳米结构修饰，使得电场不均匀，但在纳米结构的尖端附近局部增强。该项目将系统地研究LEEFT过程中细菌的行为，有四个具体目标：i）获得适合机理研究的LEEFT平台，ii）了解LEEFT过程中细菌灭活的机制，iii）揭示LEEFT装置中细胞运输的过程，以及iv）开发LEEFT的机理模型用于性能预测。核心假设是在LEEFT期间，细菌通过流体动力学、电泳力和扩张力的组合被运输到具有强电场的区域，然后主要由于不可逆的电穿孔而失活。本项目中的一些平台将构建在使用微机电系统（MEMS）技术制造的芯片实验室设备上。LEEFT实验将在各种条件下进行，例如，电极材料、电脉冲频率、混合条件和模型细菌。该模型将基于COMSOL Multiphysics的实验结果构建，该软件使用先进的数值方法来分析，解决和模拟基于物理的问题。综合教育活动包括一个名为WE-HUG（高中、本科生、研究生的水安全教育和培训）的项目，该项目招募了一个由高中教师和学生组成的垂直团队，以开发和提供反映项目科学和工程方面的教育模块。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Over 800 million people worldwide do not have adequate supply of safe drinking water. In many areas serviced by drinking water treatment plants, chlorine is used to kill harmful microbes. However, chlorination can produce chemicals that are known human carcinogens. An innovative technology that can provide point-of-service treatment to areas without adequate drinking water supply is locally enhanced electric field treatment (LEEFT). High disinfection has been achieved by LEEFT operated at low voltages with a short treatment time of a few seconds. LEEFT has the added benefits of being relatively inexpensive, chemical-free, robust, and easy to operate. In this project, the PI will study how harmful microbes in drinking water are killed during LEEFT treatment. This work has the goal of developing LEEFT for wide-scale adoption for drinking water treatment to protect public health. The educational plan of this project focuses on training future environmental engineering leaders at the high school, undergraduate, and graduate level. This effort will be complimented by public outreach to increase awareness of water safety and better prepare the public to respond to disruptions in water supply due to unexpected natural disasters.LEEFT is a physical treatment process that aims to utilize a strong electric field to disrupt cell membranes and thus inactivate pathogens in drinking water. The electrodes installed in a LEEFT device are typically modified with one-dimensional nanostructures so that the electric field is not uniform but enhanced locally near the tips of the nanostructures. This project will systematically investigate the behavior of bacteria during LEEFT with four specific objectives: i) obtaining LEEFT platforms that are suitable for mechanistic study, ii) understanding the mechanisms for bacteria inactivation during LEEFT, iii) revealing the processes for cell transportation in LEEFT devices, and iv) developing a mechanistic model of LEEFT for performance prediction. The core hypothesis is that during LEEFT, bacteria are transported to the regions with strong electric field by a combination of hydrodynamic-, electrophoretic-, and dielectrophoretic-forces, and then inactivated primarily due to irreversible electroporation. Some platforms in this project will be constructed on lab-on-a-chip devices fabricated using micro-electro-mechanical-systems (MEMS) technologies. LEEFT experiments will be performed under various conditions, e.g., electrode materials, frequency of the electric pulses, mixing conditions, and model bacteria. The model will be built based on experimental results using COMSOL Multiphysics, a software using advanced numerical methods to analyze, solve, and simulate physics-based problems. The integrated educational activities involve a program entitled WE-HUG (Water-safety Education and training for High school, Undergraduate, & Graduate students), where a vertical team of high school teachers and students are recruited to develop and deliver education modules that reflect the scientific and engineering aspects of the project.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.