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UV-C LED application in disinfection of microbial pathogens in water
Citation:
Ryu, H. UV-C LED application in disinfection of microbial pathogens in water. Presented at 18th Annual EPA Drinking Water Workshop, Cincinnati, Ohio, August 30 - September 02, 2021.
Impact/Purpose:
Opportunistic waterborne pathogens are ubiquitous in both natural and engineered water systems. Particularily, opportunistic premise plumbing pathogens (OPPPs) including Legionella spp. can colonize water distribution lines and building plumbing, contaminating water supplies after it has been centrally treated. Six treatment technologies (e.g., three chlorine and three non-chlorine based methods) for effective control of waterborne pathogens in premise plumbing systems have been recognized by EPA. However, the effectiveness of each of these methods can vary, and some of them have negative effects associated with their use, including formation of disinfection byproducts, negative aesthetic effects on water and adverse health effects, and corrosion of plumbing systems. One alternative approach could be to implement “barrier protection” at the point-of-use (POU). Numerous studies have investigated the efficacy of POU filters installed in high-risk areas to prevent the transmission of waterborne pathogens to their immunocompromised hosts. The POU membrane filtration can limit exposure to pathogens; however, their short maximum lifetime (1 or 2 weeks of continuous use) and membrane clogging (or fouling) have limited their use. Therefore, it is desirable to develop new approaches of membrane cleaning for long-term use of the POU filters. In this study, we developed a UVC-LED POU device and demonstrated its efficacy for the inactivation of various microorganisms in water.
Description:
Opportunistic waterborne pathogens including Legionella spp. may persist in water distribution systems despite municipal chlorination and secondary disinfection and can cause health care-acquired infections. This warrants development of novel pathogen removal and/or inactivation systems. Ultraviolet (UV) light technology has been successfully employed in drinking water treatment against a broad suite of pathogens. It also has an advantage over many halogenated disinfectants because it can efficiently disinfect pathogens without the formation of carcinogenic disinfection by-products (DBPs). The latest UV technology of light emitting diodes (LEDs) has shown the capability to effectively inactivate waterborne pathogens including opportunistic premise plumbing pathogen. UV-LED is mercury-free and moreover has enormous potential for point-of-use (POU) water disinfection since they are much smaller, lighter, and less fragile. However, there are still many practical application challenges inherent in a POU device regarding its treatment efficacy due to water flow rate and disinfection contact time. In this presentation, we will 1) summarize our current research efforts for microbial inactivation efficacy of newly designed POU devices and 2) discuss about smart reactor design to formulate an efficient water treatment in POU application.