Formation of odorous by-products during chlorination of major amino acids in East Taihu Lake: Impacts of UV, UV/PS and UV/H2O2 pre-treatments

Luyang Cai; Lei Li; Shuili Yu; Jingxuan Guo; Stephan Kuppers; Lei Dong

doi:10.1016/j.watres.2019.07.010

Formation of odorous by-products during chlorination of major amino acids in East Taihu Lake: Impacts of UV, UV/PS and UV/H₂O₂ pre-treatments

Water Res. 2019 Oct 1:162:427-436. doi: 10.1016/j.watres.2019.07.010. Epub 2019 Jul 5.

Authors

Luyang Cai¹, Lei Li², Shuili Yu³, Jingxuan Guo¹, Stephan Kuppers⁴, Lei Dong⁵

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China.
² State Key Laboratory of Pollution Control and Resource Reuse, 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: lilei@tongji.edu.cn.
³ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China.
⁴ Forschungszentrum Juelich GmbH-ZEA, Julich, 52425, Germany.
⁵ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Shanghai Municipal Engineering Design Institute (Group) Co.,LTD, Shanghai, 200092, PR China.

PMID: 31301472
DOI: 10.1016/j.watres.2019.07.010

Abstract

Certain amino acids (AAs) can form odorous aldehydes, nitriles and N-chloroaldimines during chlorination. Ultraviolet (UV) photolysis, ultraviolet/persulfate (UV/PS) and ultraviolet/hydrogen peroxide (UV/H₂O₂) treatments have been reported to decrease trace organic contaminants in drinking water. In this study, 20 common AAs in East Taihu (ET) Lake (the main drinking water source for the surrounding cities) were determined during one year (four seasons). The impacts of UV photolysis alone and two UV-advanced oxidation process (AOP) pre-treatments on the formation of aldehydes, nitriles and N-chloroaldimines during post-chlorination of water containing three of the most detected AAs (i.e. valine (Val), leucine (Leu) and isoleucine (Ile)) in ET Lake were investigated. Results showed that the two UV-AOPs significantly decreased the odorous by-product formation from AAs compared with UV photolysis alone. The formation of N-chloroaldimines was more easily controlled than that of aldehyde and nitrile. Furthermore, UV/H₂O₂ was more effective than UV/PS at pH = 5 and 7. At pH = 9, the two UV-AOPs had similar effects and did not perform very well. In addition, the UV-AOPs controlled the formation of odorous by-products effectively at Cl/AA (molar ratio of chlorine to amino acid) ratios of 2.4 and 3.0 but increased their formation at Cl/AA ratios of 0.8 and 1.2. Experiments in real water showed that UV/H₂O₂ was more suitable for controlling the off-flavor problem caused by chlorination of AAs in ET Lake.

Keywords: Advanced oxidation technology; Aldehydes; Amino acids; N-chloroaldimines; Nitriles; Odorous by-products.

MeSH terms

Amino Acids
Halogenation
Hydrogen Peroxide
Lakes
Oxidation-Reduction
Ultraviolet Rays
Water Pollutants, Chemical*
Water Purification*

Substances

Amino Acids
Water Pollutants, Chemical
Hydrogen Peroxide