NSF-BSF: Integrated Ultraviolet (UV) and Antimicrobial Blue Light (aBL) for Enhanced Water Disinfection

This NSF-BSF project will find better ways to keep water clean without using chemicals like chlorine. Most water systems use chlorine to kill germs. It is effective against many, but not all, germs. Furthermore, it leaves chemicals in the water. This project will test two types of light to clean water – ultraviolet (UV) light and antimicrobial blue light (aBL). UV light can kill germs quickly without leaving chemicals behind, but it doesn't stop germs from growing back later. aBL can damage germs in a different way that may help keep the water clean for a much longer time. Engineers from the University of Colorado and Tel Aviv University will work together to find the ideal mix of these two types of light to treat water. The project outcomes will be safer, chemical-free ways to provide clean water. This collaborative research project will investigate integrated ultraviolet (UV) and antimicrobial blue light (aBL) disinfection technologies to improve water quality in decentralized water infrastructure such as household storage tanks, community water tanks, rainwater harvesting systems, and piped distribution systems. While UV disinfection is already widely used in centralized water treatment and point of use devices due to its proven microbial inactivation capability, its lack of disinfectant residual allows for microbial regrowth. aBL presents a complementary approach to UV in that it excites light-sensitive chromophores inside the microbes, generating reactive oxygen species that deliver damage to multiple cellular components causing permanent inactivation; yet these mechanisms and their potential to benefit water quality is not well studied. Therefore, this project will: (1) identify the most effective combinations of aBL and UV wavelengths for virus and bacteria inactivation across different water quality conditions; (2) evaluate how optimized UV and aBL conditions affect microbial regrowth, dark repair, and photoreactivation in water systems; and (3) investigate how continuous or intermittent application of UV and/or aBL influences microbial community composition, diversity, and biofilm development in storage and distribution systems, in comparison to conventional chlorine disinfection. A variety of pathogens and pathogen surrogates will be evaluated across diverse water sources drawn from the US and Israeli environments to enable testing of treatment efficacy in representative conditions. 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. NSF Award ID: 2553642 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Karl Linden | Institution: University of Colorado at Boulder, Boulder, CO | Award Amount: $435,320 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2553642 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2553642.html