Efficacy of UV-LED based advanced disinfection processes in the inactivation of waterborne fungal spores: Kinetics, photoreactivation, mechanism and energy requirements

Qiqi Wan; Ruihua Cao; Gang Wen; Xiangqian Xu; Yuancheng Xia; Gehui Wu; Yangfan Li; Jingyi Wang; Huining Xu; Yingzi Lin; Tinglin Huang

doi:10.1016/j.scitotenv.2021.150107

Efficacy of UV-LED based advanced disinfection processes in the inactivation of waterborne fungal spores: Kinetics, photoreactivation, mechanism and energy requirements

Sci Total Environ. 2022 Jan 10:803:150107. doi: 10.1016/j.scitotenv.2021.150107. Epub 2021 Sep 4.

Authors

Qiqi Wan¹, Ruihua Cao¹, Gang Wen², Xiangqian Xu¹, Yuancheng Xia¹, Gehui Wu¹, Yangfan Li¹, Jingyi Wang¹, Huining Xu¹, Yingzi Lin³, Tinglin Huang⁴

Affiliations

¹ Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, PR China.
² Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; Collaborative Innovation Center of Water Pollution Control and Water Quality Security Assurance of Shaanxi Province, Xi'an University of Architecture and Technology, Xi'an 710055, PR China. Electronic address: wengang@xauat.edu.cn.
³ Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; School of Municipal and Environmental Engineering, Jilin Jianzhu University, Changchun 130118, PR China.
⁴ Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; Collaborative Innovation Center of Water Pollution Control and Water Quality Security Assurance of Shaanxi Province, Xi'an University of Architecture and Technology, Xi'an 710055, PR China.

PMID: 34525763
DOI: 10.1016/j.scitotenv.2021.150107

Abstract

The contamination of fungi in water supply systems poses great risks to environment and human health. In this work, UV light-emitting diodes (UV-LEDs)-based advanced disinfection processes (ADPs) including UV-LEDs/hydrogen peroxide (H₂O₂), UV-LEDs/persulfate (PS) and UV-LEDs/peroxymonosulfate (PMS), were adopted for waterborne fungal spores inactivation. Overall comparisons of the UV-LEDs-based ADPs with respect to the control efficiency of photoreactivation and energy consumption were also evaluated. Results showed that culturability reduction of the fungal spores treated by UV-LEDs was not enhanced with the addition H₂O₂, PMS, and PS according to the results of heterotrophic plate counts and reaction rate constants; A. niger was expected to have higher UV resistance followed by T. harzianum and P. polonicum. However, UV-LEDs-ADPs inactivation, especially at the wavelengths of 280 and 265/280 nm, could accelerate the permeabilization of fungal spores as characterized by flow cytometry. Take P. polonicum for example, the percentage of membrane permeabilized spores was 98.0%, 98.7%, 97.6% and 82.6% after treatment by UV₂₈₀/H₂O₂, UV₂₈₀/PS, UV₂₈₀/PMS and UV₂₈₀ alone, respectively at the fluence of 100 mJ/cm². The direct attack of free radicals in the processes of UV-LEDs-ADPs further enhanced the membrane damage and lowered the photoreactivation level, thus improved the inactivation efficiency. UV-LEDs/H₂O₂ was considered as an effective process in the disinfection of fungal spores with the advantages of enhancing the damage of membrane, inhibiting photoreactivation and comparable energy consumption compared with UV-LEDs alone.

Keywords: Culturability; Disinfection; Fungal spores; Membrane permeability; UV-LEDs-ADPs.

MeSH terms

Disinfection*
Humans
Hydrogen Peroxide
Kinetics
Spores, Fungal
Ultraviolet Rays
Water Purification*

Substances

Hydrogen Peroxide