Understanding the influence of pre-ozonation on the formation of disinfection byproducts and cytotoxicity during post-chlorination of natural organic matter: UV absorbance and electron-donating-moiety of molecular weight fractions

Wen-Long Wang; Min-Yong Lee; Ye Du; Tian-Hui Zhou; Zheng-Wei Yang; Qian-Yuan Wu; Hong-Ying Hu

Environment International (Dec 2021)

Understanding the influence of pre-ozonation on the formation of disinfection byproducts and cytotoxicity during post-chlorination of natural organic matter: UV absorbance and electron-donating-moiety of molecular weight fractions

Wen-Long Wang,
Min-Yong Lee,
Ye Du,
Tian-Hui Zhou,
Zheng-Wei Yang,
Qian-Yuan Wu,
Hong-Ying Hu

Affiliations

Wen-Long Wang: Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
Min-Yong Lee: Department of Environmental Resources Research, National Institute of Environmental Research, Seogu, Incheon 22689, Republic of Korea
Ye Du: College of Architecture & Environment, Sichuan University, Chengdu 610000, PR China
Tian-Hui Zhou: Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
Zheng-Wei Yang: Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
Qian-Yuan Wu: Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; Corresponding author at: Shenzhen Laboratory of Microorganism Application and Risk Control, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China.
Hong-Ying Hu: Environmental Simulation and Pollution Control State Key Joint Laboratory, Beijing Laboratory for Environmental Frontier Technologies, School of Environment, Tsinghua University, Beijing 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China

Journal volume & issue: Vol. 157
p. 106793

Abstract

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Pre-ozonation can reduce the formation of disinfection byproducts (DBPs) and related adverse effects during subsequent chlorination, but the change of each molecular weight (MW) fraction during each step of combined pre-ozonation and post-chlorination has not been well illustrated. In this study, it was investigated in terms of electron-donating-moieties (EDMs) and UVA254 for a representative natural organic matter from Suwanee river (SRNOM). Pre-ozonation suppressed the post-chlorination of SRNOM through oxidation of almost all EDMs (>85%) and UVA254 (>90%) in high MW fractions (HMW, >3.2 kDa) and moderate EDMs (43%) and UVA254 (72%) in medium MW fractions (MMW, 1.0–3.2 kDa). Furthermore, pre-ozonation led to comparable abatements of EDMs and UVA254 for HMW fractions, but lower abatement of EDMs than UVA254 for MMW fractions. However, when t-BuOH was used as an •OH-quencher, pre-ozonation led to a few instances in which there were higher abatements of EDMs than UVA254 for the MMW fraction. These findings suggested that the HMW fraction dominantly underwent ring-cleavage of phenols via O3– or •OH-oxidation. Differently, the MMW fraction underwent ring-cleavage of phenols and quinones-formation via O3-oxidation, but occasionally underwent hydroxylation and hydro-phenol formation via •OH-oxidation. Because of forehand elimination of reactive moieties (e.g. EDMs), pre-ozonation obviously inhibited the formation of representative DBPs (67%–84% inhibition), total organic chloride (51% inhibition) and cytotoxicity (31% inhibition), but may have promoted the formation of carbonyl-DBPs (trichloroacetone and chloral hydrate). When compared with UVA254, EDMs would better for surrogate of DBPs formation. EDM abatement surrogated the formation of total organic chlorine (TOCl) and cytotoxicity following a two-stage phase, possibly because the speciation of DBPs and transformation products varied with the abatement of EDMs.

Published in Environment International

ISSN: 0160-4120 (Print)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Geography. Anthropology. Recreation: Environmental sciences
Website: https://www.journals.elsevier.com/environment-international

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