[Distribution Characteristics of Disinfection By-Products and the Effects of Booster Chlorination in Long-Distance Water Supply Systems]

Wei-Wei Bi; Sheng Ye; Jian-Quan Yu; Yu-Long Yang; Chen Chen; Qing-Song Li; Xiao-Yan Ma

doi:10.13227/j.hjkx.202001007

[Distribution Characteristics of Disinfection By-Products and the Effects of Booster Chlorination in Long-Distance Water Supply Systems]

Huan Jing Ke Xue. 2020 Jul 8;41(7):3297-3306. doi: 10.13227/j.hjkx.202001007.

[Article in Chinese]

Authors

Wei-Wei Bi¹, Sheng Ye¹, Jian-Quan Yu¹, Yu-Long Yang², Chen Chen³, Qing-Song Li⁴, Xiao-Yan Ma¹

Affiliations

¹ College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
² College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China.
³ Zhejiang Tianzheng Design Engineering Co., Ltd., Hangzhou 310000, China.
⁴ Water Resources and Environmental Institute, Xiamen University of Technology, Xiamen 361005, China.

PMID: 32608903
DOI: 10.13227/j.hjkx.202001007

Abstract

It is difficult for waterworks that add chlorine into finished water once to maintain sufficient residual chlorine at unfavorable points of the pipe network that supply water for large areas of coverage. Therefore, booster chlorination was employed for a long-distance water distribution system. The study was performed in H City with a water supply system serving about 400 km² of downtown and rural areas. The purpose of this work is to obtain the distribution characteristics of disinfection by-products (DBPs) in the booster chlorination disinfection pipe network through uniformly distributed sampling analysis. The results showed that detected DBPs include trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM) and tribromomethane (TBM), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), dichloroacetonitrile (DCAN), bromochloroacetonitrile (BCAN), and trichloronitromethane (TCNM). The concentrations of the regulated DBPs were found to be lower than the standard limits specified in the Sanitary Standard for Drinking Water (GB5749-2006). Before booster chlorination, the average concentrations of the DBPs mentioned (expressed as mean±deviation) were (8.08±3.34), (9.77±2.91), (7.38±4.82), (2.65±2.02), (2.95±3.26), (6.02±6.06), (3.13±2.48), (1.61±2.05), and (0.15±0.10) μg·L^-1, while afterwards, they were increased to (10.30±4.55), (11.73±3.60), (8.23±5.22), (2.95±2.45), (3.29±3.60), (8.15±7.58), (3.31±2.61), (1.33±2.04), and (0.12±0.06) μg·L^-1, respectively. Trihalomethanes (THMs) and haloacetic acids (HAAs) increased by 6.32%-26.60% and 5.32%-42.71%, respectively, after booster chlorination. In addition, raw water quality and seasonal changes had a certain impact on the occurrence of DBPs. The levels of DBPs in summer were generally higher than those in spring or autumn. According to the analysis of DBP formation potential of source water, finished water, and tap water, it was found that the risk of DBPs exceeding the standard limit may exist in the water supply system of H City; therefore, further optimization of the treatment process should be considered to ensure water quality.

Keywords: DBPs formation potential; booster chlorination; disinfection by-products; long-distance water supply network; water quality safety.

Publication types

English Abstract