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Enhanced inactivation of E. coli by pulsed UV-LED irradiation during water disinfection

Zou, Xiang-Yun, Lin, Yi-Li, Xu, Bin, Cao, Tong-Cheng, Tang, Yu-Lin, Pan, Yang, Gao, Ze-Chen, Gao, Nai-Yun
The Science of the total environment 2019 v.650 pp. 210-215
Escherichia coli, decontamination, disinfection, energy efficiency, irradiation, light emitting diodes, ultraviolet radiation
Pulsed ultraviolet (UV) irradiation has presented enhanced inactivation efficiency in water disinfection and food decontamination. As an emerging UV source, UV light-emitting diodes (UV-LEDs) are an attractive alternative for pulsed irradiation because they can be turned on and off with a high and adjustable frequency. In this study, disinfection efficiencies of pulsed and continuous UV-LED irradiation were compared for Escherichia coli (E. coli) inactivation in water using a high power 285 nm LED and low power 265 and 280 nm LEDs. Factors including various duty cycles, pulse frequencies and UV irradiances were evaluated. The log-inactivation of E. coli increased substantially as the duty cycle decreased from 100% to 5% at the same UV dose. For 265 and 280 nm LEDs, the log-inactivation enhancements of pulsed UV irradiation were similar. When a higher irradiance was applied, the energy efficiency enhancement of pulsed UV irradiation became more obvious. The log-inactivation of E. coli enhanced remarkably using high current pulsed irradiation of 280 nm LEDs. Compared to continuous UV irradiation, pulsed UV-LED irradiation is an attractive alternative for E. coli inactivation in water considering energy efficiency.