Virus and Bacteria Inactivation Using Ultraviolet Light-Emitting Diodes

Abstract

The control of infectious diseases is a critical challenge in developing and developed nations alike. Humans can be exposed to pathogenic microorganisms such as viruses and bacteria through numerous routes of transmission, including waterborne transmission. Accordingly, effective water disinfection processes are paramount for public health protection. In this study, the inactivation efficacy of P22 virus and Escherichia coli bacteria was tested using ultraviolet light-emitting diodes (UV LEDs), which provided effective disinfection of both waterborne microorganisms. Using a peak wavelength emission of 255, 265, or 285 nm, the batch-test, UV LED collimated beam system demonstrated high inactivation potential for both microorganisms at all wavelengths, suggesting that it could be an effective alternative to typical, low-pressure (LP) or medium-pressure (MP), mercury-based UV systems. Increased inactivation kinetics for both microorganisms was observed with decreasing wavelength (255 > 265 > 285 nm). However, the trend reversed when accounting for energy efficiency of the systems (255 < 265 < 285 nm) due to the currently lower wall plug efficiency for lower UV LED wavelength emissions. Substantial improvements in LED efficiency are needed to make them energetically competitive with current LP and MP UV technologies.