Rapid Inactivation of Fungal Spores in Drinking Water by Far-UVC Photolysis of Free Chlorine

Yongyi Wang, Ben Ma, Jing Zhao, Zhuoyun Tang, Wanxin Li, Chun He*, Dehua Xia, Karl Linden, Ran Yin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Effective and affordable disinfection technology is one key to achieving Sustainable Development Goal 6. In this work, we develop a process by integrating Far-UVC irradiation at 222 nm with free chlorine (UV222/chlorine) for rapid inactivation of the chlorine-resistant and opportunistic Aspergillus niger spores in drinking water. The UV222/chlorine process achieves a 5.0-log inactivation of the A. niger spores at a chlorine dosage of 3.0 mg L–1 and a UV fluence of 30 mJ cm–2 in deionized water, tap water, and surface water. The inactivation rate constant of the spores by the UV222/chlorine process is 0.55 min–1, which is 4.6-fold, 5.5-fold, and 1.8-fold, respectively, higher than those of the UV222 alone, chlorination alone, and the conventional UV254/chlorine process under comparable conditions. The more efficient inactivation by the UV222/chlorine process is mainly attributed to the enhanced generation of reactive chlorine species (e.g., 6.7 × 10–15 M of Cl•) instead of hydroxyl radicals from UV222 photolysis of chlorine, which is verified through both experiments and a kinetic model. We further demonstrate that UV222 photolysis damages the membrane integrity and benefits the penetration of chlorine and radicals into cells for inactivation. The merits of the UV222/chlorine process over the UV254/chlorine process also include the more effective inhibition of the photoreactivation of the spores after disinfection and the lower formation of chlorinated disinfection byproducts and toxicity.
Original languageEnglish
Pages (from-to)21876–21887
JournalEnvironmental Science and Technology
Issue number51
Early online dateDec 2023
Publication statusPublished - 2023


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