Understanding the Role of Biofilm on Disinfection By-Product Formation and Fate in the Water Distribution System

1236433Seo与我们对水处理厂中消毒副产物(DBP)形成的理解不同，在水处理厂中，水质参数和DBP的形成可以同时监测，而供水系统中DBP的形成在很大程度上是由于供水系统中发生的复杂相互作用而不能很好地理解的。最近的研究表明，生物膜的存在不仅会影响水的生物稳定性，而且会通过与残留消毒剂发生反应来影响给水的化学稳定性。此外，生物膜可以为存在于主体流体中的各种有机物质提供动态储存库，并随后将它们用作主要营养源。考虑到生物膜的持久性和当前对生物膜暴发的操作反应，包括增加残留消毒剂的浓度以灭活生物膜，生物膜可能是配水系统中DBP形成的主要因素之一。除了生物膜形成DBP的潜力增加外，最近的研究也报道了给水系统中DBPs的生物降解与异养菌的存在密切相关。虽然许多公共和工业部门正在努力克服生物膜形成的持久性及其在供水系统中的传播，但在生物膜消毒过程中可能会产生不需要的二氯苯酚。为了解决目前的知识差距，本研究旨在调查生物膜在给水系统中DBP的形成和降解中的作用。拟议的测试将应用各种生化分析工具、DBP分析、微电极技术和分子工具来监控生物膜的生长、消毒剂的运输、DPB的形成和降解，从而从机理上了解消毒剂的反应、腐烂和生物膜有机基质产生DBPs的过程。总体而言，研究成果将解决我们目前关于在供水系统中形成生物膜形成DBP的知识差距，并提高我们预测和识别有害DBP形成的能力，这将有助于保护公众健康免受有害生物膜和DBP形成的影响。在拟议的研究期间完成的任务将产生强有力的信息，以了解DBP的形成机制以及DBP在分配系统中的命运。这可能有助于许多自来水公司评估和优化生物膜控制的消毒实践，同时最大限度地减少供水系统中DBP的形成。此外，拟议的项目将为博士生提供培训和教育，并为本科生和高中生提供暑期研究机会。研究成果也将被纳入私教的本科课程。此外，研究成果将在国际和平协会为人数不足的K-12学生和洪都拉斯的工程师无国界项目开展的外联和服务活动中介绍。

1236433SeoIn contrast to our understanding of disinfection by-product (DBP) formation in water treatment plants, where water quality parameters and the formation of DBPs can be monitored simultaneously, the formation of DBPs in water distribution systems is not well understood due largely to the complexity of interactions occurring in water distribution systems. Recent studies have indicated that the presence of biofilm impacts not only the biological stability of water but also the chemical stability of water in distribution systems via reaction with residual disinfectant. Moreover, biofilm can provide a dynamic repository for various organic materials present in the bulk fluid and subsequently utilize them as a primary nutrient source. Considering the persistence of biofilm and current operational responses to biofilm outbreak in water utilities, which include increasing the concentration of residual disinfectants to inactivate biofilm, biofilm may be one of the primary contributors to DBP formation in distribution systems. Beyond increased DBP formation potential from biofilm, recent studies also reported that biological degradation of DBPs in water distribution system was strongly related to the presence of heterotrophic bacteria. While many public and industrial sectors are working to overcome the persistence of biofilm formation and its dissemination in water distribution systems with disinfection practices, unwanted DBPs may be generated during biofilm disinfection. To address the current knowledge gap, this study aims to investigate the role of biofilm on DBP formation and degradation in water distribution systems. The proposed tests will apply various biochemical analysis tools, DBP analysis, microelectrode techniques, and molecular tools to monitor biofilm growth, disinfectant transport, DPB formation, and degradation, thus providing a mechanistic understanding of reactions, decay of disinfectants, and the production of DBPs by the organic matrix of biofilm. Overall, research outcomes will address our current knowledge gap regarding DBP formation by biofilms that form in water distribution systems and improve our ability to predict and identify harmful DBP formation, which will contribute to protecting public health from both harmful biofilm and DBP formation. Tasks completed during the proposed study will generate robust information toward understanding the mechanisms of DBP formation as well as the fate of DBPs in distribution systems. This may assist many water utilities to assess and optimize disinfectant practices for biofilm control while minimizing DBP formation in water distribution systems. In addition, the proposed project will provide training and education for Ph.D students as well as summer research opportunities for undergraduate and high school students. Research findings will also be incorporated into the PI's undergraduate courses. Furthermore, research findings will be introduced in the PI's outreach and service activities for underrepresented K-12 students and for Engineers Without Borders Projects in Honduras.