Comparison of the performance of pulsed and continuous UVC-LED irradiation in the inactivation of several typical bacteria in drinking water

The ultraviolet light-emitting diode (UV-LED) is employed widely in a variety of disinfection settings due to its quick response, small size, continuously changeable pulse width, and adjustable repetition frequency. UV-LED light can be split into continuous wave (CW) and pulsed light (PL) depending on the type of radiation it emits. The relative relationship between CW and PL radiation power and UV dose is discussed in this study, with a particular emphasis on a comparison of the inactivation efficacy of 265 nm single wavelength continuous UV and pulsed light UV on E. coli, S. aureus, and B. subtilis. The experimental findings demonstrated that the logarithmic inactivation values of E. coli, S. aureus, and B. subtilis were 1.626, 1.413, and 0.68 correspondingly when the pulsed radiation intensity of PL was 14.6 times that of CW, which was 75.6%, 66.6%, and 127% greater than CW. Furthermore, S. aureus and B. subtilis were more resistant to 265 nm UVC, with E. coli being the most sensitive.