Reinvestigation on the Mechanism for Algae Inactivation by the Ultraviolet/Peracetic Acid Process: Role of Reactive Species and Performance in Natural Water

This study provided an in-depth understanding of enhanced algae inactivation by combining ultraviolet and peracetic acid (UV/PAA) and selecting Microcystis aeruginosa as the target algae species. The electron paramagnetic resonance (EPR) tests and scavenging experiments provided direct evidence on t...

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Bibliographic Details
Published in:Environmental science & technology 2023-11, Vol.57 (45), p.17629-17639
Main Authors: Cao, Lisan, Wang, Zongping, Cheng, Yujie, Chen, Yiqun, Liu, Zizheng, Yue, Siyang, Ma, Jun, Xie, Pengchao
Format: Article
Language:English
Subjects:
Algae
Coagulation
Deactivation
Electron paramagnetic resonance
Electron spin resonance
Inactivation
Microcystis
Peracetic acid
Physico-Chemical Treatment and Resource Recovery
Rate constants
Scavenging
Singlet oxygen
Water depth
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Summary:This study provided an in-depth understanding of enhanced algae inactivation by combining ultraviolet and peracetic acid (UV/PAA) and selecting Microcystis aeruginosa as the target algae species. The electron paramagnetic resonance (EPR) tests and scavenging experiments provided direct evidence on the formed reactive species (RSs) and indicated the dominant role of RSs including singlet oxygen (1O2) and hydroxyl (HO•) and organic (RO•) radicals in algae inactivation. Based on the algae inactivation kinetic model and the determined steady-state concentration of RSs, the contribution of RSs was quantitatively assessed with the second-order rate constants for the inactivation of algae by HO•, RO•, and 1O2 of 2.67 × 109, 3.44 × 1010, and 1.72 × 109 M–1 s–1, respectively. Afterward, the coexisting bi/carbonate, acting as a shuttle, that promotes the transformation from HO• to RO• was evidenced to account for the better performance of the UV/PAA system in algae inactivation under the natural water background. Subsequently, along with the evaluation of the UV/PAA preoxidation to modify coagulation–sedimentation, the possible application of the UV/PAA process for algae removal was advanced.
ISSN:0013-936X
1520-5851
DOI:10.1021/acs.est.3c05694