Abundance and composition of indigenous bacterial communities in a multi-step biofiltration-based drinking water treatment plant

• Published in: Water research (Oxford) 2014-10, Vol.62, p.40-52
• Main Authors: Lautenschlager, Karin, Hwang, Chiachi, Ling, Fangqiong, Liu, Wen-Tso, Boon, Nico, Köster, Oliver, Egli, Thomas, Hammes, Frederik
• Format: Article
• Language: English
• Subjects: 454 pyrosequencing; Adenosine tri-phosphate (ATP); Applied sciences; Bacteria; Bacteria - enzymology; Bacteria - growth & development; Bacteriodetes; Biodegradation, Environmental; Biodiversity; Biofilter; Biomass; Carbon - isolation & purification; Charcoal - chemistry; Communities; Drinking water; Drinking Water - microbiology; Drinking water and swimming-pool water. Desalination; Effluents; Exact sciences and technology; Filtration - methods; Microbial communities; Microorganisms; Nitrospira; Organic Chemicals - isolation & purification; Planctomycetes; Plankton - growth & development; Plants (organisms); Pollution; Proteobacteria; Sand; Switzerland; Waste Disposal, Fluid; Water Pollutants, Chemical - isolation & purification; Water Purification - methods; Water Quality; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2014.05.035

Indigenous bacterial communities are essential for biofiltration processes in drinking water treatment systems. In this study, we examined the microbial community composition and abundance of three different biofilter types (rapid sand, granular activated carbon, and slow sand filters) and their respective effluents in a full-scale, multi-step treatment plant (Zürich, CH). Detailed analysis of organic carbon degradation underpinned biodegradation as the primary function of the biofilter biomass. The biomass was present in concentrations ranging between 2–5 × 1015 cells/m3 in all filters but was phylogenetically, enzymatically and metabolically diverse. Based on 16S rRNA gene-based 454 pyrosequencing analysis for microbial community composition, similar microbial taxa (predominantly Proteobacteria, Planctomycetes, Acidobacteria, Bacteriodetes, Nitrospira and Chloroflexi) were present in all biofilters and in their respective effluents, but the ratio of microbial taxa was different in each filter type. This change was also reflected in the cluster analysis, which revealed a change of 50–60% in microbial community composition between the different filter types. This study documents the direct influence of the filter biomass on the microbial community composition of the final drinking water, particularly when the water is distributed without post-disinfection. The results provide new insights on the complexity of indigenous bacteria colonizing drinking water systems, especially in different biofilters of a multi-step treatment plant. [Display omitted] •Microbiological changes during drinking water treatment assessed with multiple methods.•Similar concentrations of about 1015 cells/m3 found in different full-scale biofilters.•All biofilter types displayed high phylogenetic, enzymatic and metabolic diversity.•Proteobacteria, Planctomycetes, Acidobacteria, Bacteriodetes, Nitrospira and Chloroflexi dominated.•The final water quality was shaped by the communities in the preceding biofilters.