Application of UV Light–Emitting Diodes to Adenovirus in Water

Abstract

A ring-shaped disinfection apparatus has been developed containing twenty ultraviolet-light-emitting diodes (UV-LEDs) with emission at 285 nm. The apparatus was applied to Escherichia coli, Qβ, MS2, and adenovirus in water. The reduction-equivalent fluence in the apparatus was determined, based on a modification of the protocol for the bench-scale challenge test by low-pressure (LP) UV lamp systems (LPUV). All species demonstrated log-linear inactivation profiles versus the fluence, and the inactivation rate constants for E. coli, Qβ, MS2, and adenovirus were 0.157, 0.037, 0.029, and 0.023 cm2/mJ, respectively. The inactivation rate constant for adenovirus under the UV-LED exposure (kUV-LED′) was higher than that under a LPUV lamp (kLPUV′), and the ratio of kUV-LED′ to kLPUV′, which is approximated as a germicidal factor at 285 nm, was 1.15 for adenovirus. To conclude, this study demonstrated a high potential of the 285 nm UV-LEDs to inactivate microorganisms in water. The germicidal factor found for adenovirus implies that the 285 nm UV-LED could be a good option to inactivate adenovirus in water.