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

Xiang-Yun Zou; Yi-Li Lin; Bin Xu; Tong-Cheng Cao; Yu-Lin Tang; Yang Pan; Ze-Chen Gao; Nai-Yun Gao

doi:10.1016/j.scitotenv.2018.08.367

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

Sci Total Environ. 2019 Feb 10;650(Pt 1):210-215. doi: 10.1016/j.scitotenv.2018.08.367. Epub 2018 Aug 27.

Authors

Xiang-Yun Zou¹, Yi-Li Lin², Bin Xu³, Tong-Cheng Cao⁴, Yu-Lin Tang¹, Yang Pan⁵, Ze-Chen Gao⁴, Nai-Yun Gao⁴

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
² Department of Safety, Health and Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 824, Taiwan, ROC.
³ State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China. Electronic address: tjwenwu@tongji.edu.cn.
⁴ State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
⁵ State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.

PMID: 30196221
DOI: 10.1016/j.scitotenv.2018.08.367

Abstract

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.

Keywords: Energy efficiency; Escherichia coli; Pulsed irradiation; UV disinfection; Ultraviolet light-emitting diode (UV-LED).

MeSH terms

Disinfection / methods*
Escherichia coli / radiation effects*
Ultraviolet Rays*
Water Microbiology*
Water Purification / methods*