Formation of disinfection by-products in a UV-activated mixed chlorine/chloramine system

Zhi Liu; Bin Xu; Tian-Yang Zhang; Chen-Yan Hu; Yu-Lin Tang; Zheng-Yu Dong; Tong-Cheng Cao; Mohamed Gamal El-Din

doi:10.1016/j.jhazmat.2020.124373

Formation of disinfection by-products in a UV-activated mixed chlorine/chloramine system

J Hazard Mater. 2021 Apr 5:407:124373. doi: 10.1016/j.jhazmat.2020.124373. Epub 2020 Oct 24.

Authors

Zhi Liu¹, Bin Xu¹, Tian-Yang Zhang², Chen-Yan Hu³, Yu-Lin Tang¹, Zheng-Yu Dong¹, Tong-Cheng Cao⁴, Mohamed Gamal El-Din⁵

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 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: tianyang1815@126.com.
³ College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, PR China.
⁴ School of Chemical Science and Engineering, Key Laboratory of Road and Traffic Engineering of Ministry of Education, Tongji University, Shanghai 200092, PR China.
⁵ Department of Civil and Environmental Engineering, University of Alberta, Edmonton AB T6G1H9, Canada.

PMID: 33153788
DOI: 10.1016/j.jhazmat.2020.124373

Abstract

In recent years, ultraviolet (UV) irradiation coupled with chlor(am)ination process is ubiquitous in secondary water supply systems in many cities of China. However, the disinfection by-products (DBPs) formation in a UV-activated mixed chlorine/chloramine system (MCCS) still remains unclear. In this study, the DBPs formation in a UV-activated MCCS was systematically investigated, considering influencing factors including the mass ratios of free chlorine to NH₂Cl, UV irradiation, pH values, NOM types, Br^- concentration and toxicity of the DBPs. Results indicated that DBPs formation decreased remarkably as mass ratio of free chlorine to NH₂Cl changed from 5:0 to 0:5. The DBPs formation in humic acid (HA)-containing water was the highest, followed by those in fulvic acid (FA) and algal organic matter (AOM). Besides, better control of the DBP-related calculated toxicity can be achieved in acidic conditions regardless of the UV irradiation. Furthermore, in the presence of Br^-, a significant reduction of DBPs formation could be achieved in a UV-activated MCCS. The findings also demonstrated that DBPs formation in real water can be effectively reduced at high UV fluence in a MCCS.

Keywords: Advanced oxidation processes (AOPs); Disinfection by-products (DBPs); Mixed chlorine/chloramine system (MCCS); Toxicity; Ultraviolet (UV) irradiation.

Publication types

Research Support, Non-U.S. Gov't