Sulfadiazine destruction by chlorination in a pilot-scale water distribution system: Kinetics, pathway, and bacterial community structure

• Published in: Journal of hazardous materials Vol. 366; pp. 88 - 97
• Main Authors: Dong, Feilong, Li, Cong, Crittenden, John, Zhang, Tuqiao, Lin, Qiufeng, He, Guilin, Zhang, Weiqiu, Luo, Jinming
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.03.2019
• Subjects: 16S rRNA; Chlorination; Pathway; Sulfadiazine; Toxicity; Water distribution system; Sulfadiazine; 16S rRNA; Water distribution system; Chlorination; Toxicity; Pathway
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2018.11.096

[Display omitted] •Degradation of SDZ by chlorination could be described by second-order kinetics.•Degradation of SDZ by chlorination accelerated with an increase in temperature.•Degradation of SDZ by chlorination varies with pipe materials of the WDS.•The identified oxidized products of SDZ describe the reaction pathways.•The influence of pipe materials on microbial community structure in WDS was studied. Sulfadiazine (SDZ) has been frequently detected in surface waters in recent years. We evaluated the kinetics, mechanisms, intermediate products and bacterial community structure that result from the reaction of SDZ with free chlorine (HOCl/OCl−). We examined this in a pilot-scale water distribution system. Neutral pH had the fastest rate of destruction of SDZ. A second-order reaction constant for the destruction of SDZ by chlorine increased with increasing concentration of free chlorine (FC). For different pipe materials, the rate of SDZ degradation decreased as follows: stainless steel (SS) pipe > polyethylene (PE) pipe > ductile iron (DI) pipe. Based on the less complex bacterial diversity and more chlorine-resistant by 16S ribosomal ribonucleic acid (rRNA) gene analysis, SS pipe and PE pipe were more suitable in SDZ degradation in water distribution system (WDS) than DI pipe. In addition, the transformation products from SDZ chlorination were identified by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry, and the products included SO2 extrusion products, haloacetic acids and trihalomethanes. Toxicity tests further confirmed that the toxicity of SDZ chlorination was higher both in low FC (0.7 mg/L) and high FC (1.3 mg/L) in WDS.