CAREER: Designing stable biofilms for drinking water systems

Drinking water is not sterile. Many microbes thrive in biofilms along water pipe walls. While most of these microbes do not cause harm, some are pathogens that can cause respiratory infections. These pathogens cost more than $2.4 billion in healthcare costs each year. Water distributors and building owners try to kill biofilm bacteria with disinfectants and high temperatures, but biofilms are resilient. The goal of this career project is to engineer a biofilm that promotes good bacteria that can outcompete unwanted ones. If successful, this strategy to work with biofilms, instead of against them, will lead to more stable drinking water quality. It will also be more sustainable, with lower energy and material costs. Understanding more about biofilms in our water pipes will improve guidance that makes drinking water safe. Educational and outreach activities will strengthen the Nation’s STEM workforce and empower the public to take control of their own drinking water quality. Most microbes in drinking water systems reside in biofilms along pipe walls. While these microbes are largely benign, drinking water pathogens associated with the immunocompromised, or opportunistic pathogens, thrive in biofilms. Legionella pneumophila, Pseudomonas aeruginosa, and non-tuberculous Mycobacteria (NTM) are estimated to cost more than $2.4 billion in healthcare costs each year. Current strategies to control these pathogens in plumbing systems, if effective, are unsustainable, with high energy, maintenance, and material costs. Even with disinfectant, biofilm formation in plumbing is largely inevitable. New strategies are required to control these biofilms and reduce exposure to pathogens from drinking water. An approach embracing biology can be more sustainable and provide greater stability in plumbing systems. This project will engineer drinking water biofilms to have long-term biological stability and resistance to invasion, especially by pathogens. The scalable approach will establish a competitive model microbial consortium specific to drinking water. At the bench-scale, coupon experiments and a cell printing method will be used to control initial biofilm colonization. A unique Plumbing Testing Facility will be used to assess long-term biofilm stability at real scale. Finally, the same facility and pure culture experiments will be used to explore and validate models of biofilm-water interactions. This approach considers the unique reality of plumbing, with high surface area to volume ratios and intermittent flow. Using a community ecology framework allows connection of this applied project to broader understanding of dispersal and selection processes. Educational activities will help educate the next generation of students in public health, biological engineering, and environmental engineering. They will also educate the public on drinking water and biofilm engineering to increase scientific literacy. 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.