Water flowing through drinking water distribution systems can become contaminated due to interruptions in supply or periods of low water pressure. In the US, these interruptions are currently more common due to aging infrastructure systems and natural disasters. Outside the US, more than one billion people receive water through piped distribution systems for less than 24 hours per day. This project will study the effect of regular pressure loss in water distribution systems on water quality. In collaboration with the University of Sheffield in England, this research will provide a better understanding of the effect of intermittently operated piped water systems on water quality which can lead to strategies for the reduction of the spread of waterborne diseases. Additionally, this project will help train engineering students for engagement in international collaborations and global workforces. The research team will broaden participation in engineering by recruiting undergraduate and graduate students from underrepresented populations and by developing education modules on drinking water distribution systems for K-12 audiences.
While the influence of momentary loss of pressure in otherwise continuous supplies in water distribution systems has been studied, the effect of chronic water interruptions on the microbiology of pipes was not previously examined under controlled conditions. The contribution of this proposed research is to elucidate the fundamental mechanisms by which chronic interruptions influence the microbial ecology and behavior of pathogens in biofilms and in the bulk phase of the water supply. The central hypothesis is that frequent interruptions to pressurized water supply affect the structure and composition of biofilms, the growth of bacteria, and the persistence and release of enteric pathogens within the pipes. The sum effect of these frequent interruptions is negatively influencing the quality of the water received at the tap. To test this hypothesis, the research group of Emily Kumpel, in collaboration with researchers at the University of Sheffield in England, will: 1) describe the microbiology of bulk water and biofilms in continuously and intermittently supplied pipes; 2) determine the fate and transport of indicators of pathogenic organisms in intermittently supplied pipes; and 3) model the impact of varying hours of supply in intermittent supply on the risk of waterborne disease. This proposed research will use an internationally-unique 600 m long temperature-controlled, real-scale pipe loop facility at the University of Sheffield. The three hydraulically-isolated loops in this facility will be operated with separate supply regimes to establish baseline quality parameters, determine the presence, composition, and function of microbial communities, study the biofilm structure and composition, and investigate the survival and growth of pathogen indicators. Finally, data generated from these experiments will be used to develop a quantitative microbial risk assessment model to evaluate the impact of varying hours of supply on the potential risk of waterborne disease. By gaining a more fundamental understanding of how these supply interruptions affect the microbiology of pipes, this research can lead to the development of strategies for improving water quality. Overall, this research can strengthen US water security by identifying and reducing the risks to health posed by chronically intermittent networks and by interruptions to otherwise continuously pressurized distribution systems.
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.
