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Effects of phosphate-enhanced ozone/biofiltration on formation of disinfection byproducts and occurrence of opportunistic pathogens in drinking water distribution systems.
- Source :
-
Water research [Water Res] 2018 Aug 01; Vol. 139, pp. 168-176. Date of Electronic Publication: 2018 Mar 29. - Publication Year :
- 2018
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Abstract
- The effects of ozone-biologically activated carbon (O <subscript>3</subscript> -BAC) treatment with various phosphate doses (0, 0.3 or 0.6 mg/L) were investigated on the formation of disinfection by-products (DBPs) and occurrence of opportunistic pathogens (OPs) in drinking water distribution systems (DWDSs) simulated by annular reactors (ARs). It was found that the lowest DBPs and the highest inactivation of OPs such as Mycobacterium spp., Mycobacterium avium, Aeromonas spp., Pseudomonas aeruginosa and Hartmanella vermiformis, occurred in the effluent of the AR with 0.6 mg/L phosphate addition. Based on the results of different characterization techniques, for the AR with 0.6 mg/L phosphate-enhanced O <subscript>3</subscript> -BAC treatment, dissolved organic carbon in the influent exhibited the lowest concentration and most stable fraction due to the improved biodegradation effect. Moreover, the total amount of suspended extracellular polymeric substances (EPS) in the bulk water of the AR decreased greatly, resulting in the lowest chlorine consumption and DBPs formation in the AR. In Fourier transform infrared spectra of the suspended EPS, the amide II band (1600-1500 cm <superscript>-1</superscript> ) disappeared and the protein/polysaccharide ratio decreased remarkably, indicating the destruction of protein and a decrease in hydrophobicity. Moreover, β-sheets and α-helices in the protein secondary structures were degraded while the random coils increased sharply as phosphate addition increased to 0.6 mg/L, inhibiting microbial aggregation and hence weakening the chlorine-resistance capability. Thus, most of the OPs in suspended biofilms were more easily inactivated by residual chlorine, resulting in the lowest OPs occurrence in the effluent of the AR. Our findings indicated that enhancing the efficiency of the BAC filter by adding phosphate is a promising method for improving water quality in DWDSs.<br /> (Copyright © 2018 Elsevier Ltd. All rights reserved.)
- Subjects :
- Bacteria drug effects
Bacteria isolation & purification
Bacteria metabolism
Biofilms
Carbon chemistry
Chlorine pharmacology
Disinfectants pharmacology
Drinking Water chemistry
Filtration
Water Microbiology
Water Pollutants analysis
Water Pollutants chemistry
Water Pollutants metabolism
Disinfection methods
Drinking Water microbiology
Oxidants pharmacology
Ozone pharmacology
Phosphates pharmacology
Water Purification methods
Subjects
Details
- Language :
- English
- ISSN :
- 1879-2448
- Volume :
- 139
- Database :
- MEDLINE
- Journal :
- Water research
- Publication Type :
- Academic Journal
- Accession number :
- 29635153
- Full Text :
- https://doi.org/10.1016/j.watres.2018.03.073