Disinfection exhibits systematic impacts on the drinking water microbiome

Dai, Zihan; Sevillano-Rivera, Maria C.; Calus, Szymon T.; Santos, Quyen Melina Bautista-de los; Eren, A. Murat; Wielen, P.W.J.J. van der; Ijaz, Umer Zeeshan; Pinto, Ameet J.

doi:10.1186/s40168-020-00813-0

Cited by 63 publications

(123 citation statements)

References 81 publications

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“…For instance, the microbial concentrations in finished drinking water can vary from 10 3 and 10 5 cells/mL 11–15 , depending on the presence, absence, and concentrations of the disinfectant residual. Disinfectant residuals not only impact community size, but also impact community structure 3,10,16–18 and functional potential 18,19 . Similarly, filtration processes impact downstream microbial communities both by filtration-mediated seeding (Pinto et al ., 2012) and through the biologically mediated removal of nutrients making them unavailable for microbial growth downstream 11,12,20,21 .…”

Section: Introductionmentioning

confidence: 99%

Reproducible microbial community dynamics of two drinking water systems treating similar source waters

Potgieter

Pinto²,

Havenga

et al. 2019

Preprint

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26In addition to containing higher concentrations of organics and bacterial cells, 27 surface waters are often more vulnerable to pollution and microbial contamination 28 with intensive industrial and agricultural activities frequently occurring in areas 29 surrounding the water source. Therefore, surface waters typically require additional 30 treatment, where the choice of treatment strategy is critical for water quality. Using 31 16S rRNA gene profiling, this study provides a unique opportunity to simultaneously 32 investigate and compare two drinking water treatment plants and their 33 corresponding distribution systems. The two treatment plants treat similar surface 34 waters, from the same river system, with the same sequential treatment strategies. 35 Here, the impact of treatment and distribution on the microbial community within and 36 between each system was compared over an eight-month sampling campaign. 37 Overall, reproducible spatial and temporal dynamics within both DWTPs and their 38 corresponding DWDSs were observed. Although source waters showed some 39 dissimilarity in microbial community structure and composition, pre-disinfection 40 treatments (i.e. coagulation, flocculation, sedimentation and filtration) resulted in 41 highly similar microbial communities between the filter effluent samples. This 42 indicated that the same treatments resulted in the development of similar microbial 43 communities. Conversely, post-disinfection (i.e. chlorination and chloramination) 44 resulted in increased dissimilarity between disinfected samples from the two 45 systems, showing alternative responses of the microbial community to disinfection. 46 Lastly, it was observed that within the distribution system the same dominant taxa 47 were selected where samples increased in similarity with increased residence time. 48 Although, differences were found between the two systems, overall treatment and 49 distribution had a similar impact on the microbial community in each system. This 50 study therefore provides valuable information on the impact of treatment and 51 distribution on the drinking water microbiome. 52 53 Keywords: drinking water treatment; drinking water distribution; disinfection; 54 microbial community dynamics; Illumina MiSeq. 55 56 Highlights 57  Source waters show some dissimilarity in microbial community. 58  Treatment processes increases similarity and selects for the same dominant 59 taxa. 60  Differential response to chlorination causing increased dissimilarity and 61 variation. 62  Stabilisation of DWDS microbial community through selection of same 63 dominant taxa. 64  Microbial community dynamics are reproducible between the two systems. 65 66 Abbreviations 67 DWDS, drinking water distribution system; DWTP, drinking water treatment plant; 68 DADA2, Divisive Amplicon Denoising Algorithm; ASV, amplicon sequence variant; 69 AMOVA, analysis of molecular variance; MRA, mean relative abundance; PCoA, 70 Principal coordinate analysis; ANOVA, One-way analysis of varianc...

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Section: Introductionmentioning

confidence: 99%

Reproducible microbial community dynamics of two drinking water systems treating similar source waters

Potgieter

Pinto²,

Havenga

et al. 2019

Preprint

Self Cite

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“…However, low DNA concentration or any genetic markers have been demonstrated to give high false-negative results, increased false discovery and artefactual results [44,52] that is likely to be the case for sequencing-based studies in chlorinated drinking water [29]. We found that many reported drinking water microbiome studies from chlorinated systems (including 16s rRNA amplicon sequencing/ metabarcoding, metagenomics) [20,[56][57][58][59][60][61][62][63][64] often exclude raw experimental data of extracted DNA concentrations that is crucial to assess the quality of the sequencing results.…”

Section: No Impact Of Water Volume On Dna Recoverymentioning

confidence: 87%

Evaluation of DNA extraction yield from a chlorinated drinking water distribution system

et al. 2021

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Desalination technology based on Reverse Osmosis (RO) membrane filtration has been resorted to provide high-quality drinking water. RO produced drinking water is characterized by a low bacterial cell concentration. Monitoring microbial quality and ensuring membrane-treated water safety has taken advantage of the rapid development of DNA-based techniques. However, the DNA extraction process from RO-based drinking water samples needs to be evaluated regarding the biomass amount (filtration volume) and residual disinfectant such as chlorine, as it can affect the DNA yield. We assessed the DNA recovery applied in drinking water microbiome studies as a function of (i) different filtration volumes, (ii) presence and absence of residual chlorine, and (iii) the addition of a known Escherichia coli concentration into the (sterile and non-sterile, chlorinated and dechlorinated) tap water prior filtration, and directly onto the (0.2 μm pore size, 47 mm diameter) mixed ester cellulose membrane filters without and after tap water filtration. Our findings demonstrated that the co-occurrence of residual chlorine and low biomass/cell density water samples (RO-treated water with a total cell concentration ranging between 2.47 × 102–1.5 × 103 cells/mL) failed to provide sufficient DNA quantity (below the threshold concentration required for sequencing-based procedures) irrespective of filtration volumes used (4, 20, 40, 60 L) and even after performing dechlorination. After exposure to tap water containing residual chlorine (0.2 mg/L), we observed a significant reduction of E. coli cell concentration and the degradation of its DNA (DNA yield was below detection limit) at a lower disinfectant level compared to what was previously reported, indicating that free-living bacteria and their DNA present in the drinking water are subject to the same conditions. The membrane spiking experiment confirmed no significant impact from any potential inhibitors (e.g. organic/inorganic components) present in the drinking water matrix on DNA extraction yield. We found that very low DNA content is likely to be the norm in chlorinated drinking water that gives hindsight to its limitation in providing robust results for any downstream molecular analyses for microbiome surveys. We advise that measurement of DNA yield is a necessary first step in chlorinated drinking water distribution systems (DWDSs) before conducting any downstream omics analyses such as amplicon sequencing to avoid inaccurate interpretations of results based on very low DNA content. This study expands a substantial source of bias in using DNA-based methods for low biomass samples typical in chlorinated DWDSs. Suggestions are provided for DNA-based research in drinking water with residual disinfectant.

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“…Whereas the focus of this study was solely on the bacterial numbers reached by the innate waterborne community after treatment and how quickly this happened, the composition of the new microbial community is of hygienic relevance. Interestingly, it was recently reported that disinfection exerts a selective pressure on the drinking water microbiome toward microorganisms that can utilize decay products from inactivated biomass (Dai et al 2020).…”

Section: Discussionmentioning

confidence: 99%

Thermal and chemical disinfection of water and biofilms: only a temporary effect in regard to the autochthonous bacteria

Nocker

Lindfeld

Wingender

et al. 2021

Journal of Water and Health

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Thermal and chemical disinfection of technical water systems not only aim at minimizing the level of undesired microorganisms, but also at preventing excessive biofouling, clogging and interference with diverse technical processes. Typically, treatment has to be repeated in certain time intervals, as the duration of the effect is limited. The transient effect of disinfection was demonstrated in this study applying different treatments to water and biofilms including heat, chlorination, a combination of hydrogen peroxide and peracetic acid and monochloramine. Despite the diverse treatments, the reduction in live bacteria was followed by regrowth in all cases, underlining the universal validity of this phenomenon. The study shows that autochthonous bacteria could reach the concentrations given prior to treatment. The reason is seen in the nutrient concentration that has not changed and that forms the basis for regrowth. Nutrients are released by disinfection from lysed cells or are still fixed in dead biomass that is subsequently scavenged by necrotrophic growth. Treatment cycles therefore only provide a transient reduction of water microbiology if nutrients are not removed. When aiming at greater sustainability of the effect, biocidal treatment has to be equally concerned about nutrient removal by subsequent cleaning procedures as about killing efficiency.

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Disinfection exhibits systematic impacts on the drinking water microbiome

Cited by 63 publications

References 81 publications

Reproducible microbial community dynamics of two drinking water systems treating similar source waters

Reproducible microbial community dynamics of two drinking water systems treating similar source waters

Evaluation of DNA extraction yield from a chlorinated drinking water distribution system

Thermal and chemical disinfection of water and biofilms: only a temporary effect in regard to the autochthonous bacteria

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