Application of UV Light-Emitting Diodes to Adenovirus in Water

A ring-shaped disinfection apparatus has been developed containing twenty ultraviolet-light-emitting diodes (UV-LEDs) with emission at 285nm. The apparatus was applied to Escherichia coli, Q, 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, Q, MS2, and adenovirus were 0.157, 0.037, 0.029, and 0.023cm2/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 285nm, was 1.15 for adenovirus. To conclude, this study demonstrated a high potential of the 285nm UV-LEDs to inactivate microorganisms in water. The germicidal factor found for adenovirus implies that the 285nm UV-LED could be a good option to inactivate adenovirus in water. (C) 2015 American Society of Civil Engineers.