Disinfection-residual bacteria (DRB) after chlorine dioxide treatment: Microbial community structure, regrowth potential, and secretion characteristics

• Published in: Journal of hazardous materials 2024-09, Vol.476, p.135136, Article 135136
• Main Authors: Tang, Yingcai, Wu, Yin-Hu, Wang, Hao-Bin, Chen, Zhuo, Wang, Wen-Long, Ni, Xin-Ye, Xu, Ao, Hu, Hong-Ying
• Format: Article
• Language: English
• Subjects: Acinetobacter; Aeromonas; Chlorine dioxide; community structure; denitrification; disinfection; Disinfection-residual bacteria (DRB); factor analysis; fluorescence; Fluorescent substance; Lactobacillus; microbial communities; Mycobacterium; polymers; Pseudomonas; Reclaimed water; regrowth; Regrowth characteristics; secretion; species richness; Staphylococcus; total organic carbon; ultrafiltration
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.135136

This study investigates the effects of chlorine dioxide (ClO2) disinfection on the community structure, regrowth potential, and metabolic product secretion of disinfection-residual bacteria (DRB) in secondary effluent (SE), denitrification filter effluent (DFE), and ultrafiltration effluent (UE). Results show that ClO2 effectively reduces bacteria in SE and UE, achieving log removal values exceeding 3 at 1 mg/L within 30 min. A salient positive correlation (R2 > 0.95) exists between changes in total fluorescence intensity and disinfection efficacy. Post-treatment, Acinetobacter abundance increased in SE, while Pseudomonas decreased in DFE and UE. At lower ClO2 concentrations, Staphylococcus, Mycobacterium, Aeromonas, and Lactobacillus increased in DFE, but decreased at higher concentrations. After storage, bacterial counts in disinfected samples exceeded those in the control group, surpassing 105 CFU/mL. Despite an initial decline, species richness and evenness partially recovered but remained lower than control levels. Culturing DRB for 72 h showed elevated extracellular polymeric substances (EPS) secretion, quantified as total organic carbon (TOC), ranging from 5 to 27 mg/L, with significantly higher EPS in the disinfection group. Parallel factor analysis with self-organizing maps (PARAFAC-SOM) effectively differentiated water sample types and EPS fluorescent substances, underscoring the potential of three-dimensional fluorescence as an indirect measure of ClO2 disinfection efficacy. [Display omitted] •ClO2 effectively inactivated pathogens in reclaimed water.•EPS secretion of DRB increased after ClO2 disinfection.•EEM can serve as an alternative indicator for ClO2 disinfection of reclaimed water.•PARAFAC-SOM effectively distinguished differences in fluorescent substances.•Functional/phenotypic predictions elucidate changes in EPS characteristics.