Medium shapes the microbial community of water filters with implications for effluent quality

Vignola, Marta; Werner, David; Wade, Matthew J.; Meynet, Paola; Davenport, Russell J.

doi:10.1016/j.watres.2017.09.042

Cited by 85 publications

(59 citation statements)

References 37 publications

(56 reference statements)

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“…It is an often under-appreciated, complementary element of microbial ecology, which is essential for determining bacterial growth rates and substrate utilisation kinetics, for theoretical modelling (Meynet et al, 2014(Meynet et al, , 2012, mass balances (Vignola et al, 2018) and for comprehensive interpretation of microbiome surveys (Props et al, 2017). Therefore, the search for rapid and reliable techniques to estimate microbial cell numbers in diverse environments, and in filter media specifically, has become a scientific priority (Davis, 2014).…”

Section: Introductionmentioning

confidence: 99%

Flow-cytometric quantification of microbial cells on sand from water biofilters

et al. 2018

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a b s t r a c tRapid quantification of absolute microbial cell abundances is important for a comprehensive interpretation of microbiome surveys and crucial to support theoretical modelling and the design of engineered systems. In this paper, we propose a protocol specifically optimised for the quantification of microbial abundances in water biofilters using flow cytometry (FCM). We optimised cell detachment from sand biofilter particles for FCM quantification through the evaluation of five chemical dispersants (NaCl, Triton-X100, CaCl 2 , sodium pyrophosphate (PP), Tween 80 combined with PP), different mechanical pretreatments (low and high energy sonication and shaking) and two fixation methods (glutaraldehyde and ethanol). The developed protocol was cross-compared using other established and commonly employed methods for biomass quantification in water filter samples (adenosine triphosphate (ATP) quantification, real-time quantitative PCR (qPCR) and volatile solids (VS)). The highest microbial count was obtained by detaching the biofilm from biofilter grains and dispersing clusters into singles cells using Tween 80 and sodium pyrophosphate combined with four steps of high energy sonication (27W, for 80 s each step); glutaraldehyde was shown to be the best fixative solution. The developed protocol was reliable and highly reproducible and produced results that are comparable to data from alternative quantification methods. Indeed, high correlations were found with trends obtained through ATP and qPCR (r ¼ 0.98 and r ¼ 0.91) measurements. The VS content was confirmed as an inaccurate method to express biomass in sand samples since it correlated poorly with all the other three methods (r ¼ 0.005 with FCM, 0.002 with ATP and 0.177 with qPCR). FCM and ATP showed the strongest agreement between absolute counts with a slope of the correlation equal to 0.7, while qPCR seemed to overestimate cell counts by a factor of ten. The rapidity and reproducibility of the method developed make its application ideal for routine quantification of microbial cell abundances on sand from water biofilters and thus useful in revealing the ecological patterns and quantifying the metabolic kinetics involved in such systems.

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Section: Introductionmentioning

confidence: 99%

Flow-cytometric quantification of microbial cells on sand from water biofilters

et al. 2018

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“…For example, historical contingency, or the order in which microorganisms arrive, has been shown to play a large role in the resulting community [14,15] and has also been shown to impact interactions [16]. Both niche and neutral factors have been shown to impact microbial community assembly on sand filters [17]. Understanding the influence of selection versus neutral factors will be important for engineering the microbial community of EIS to enhance biotransformation since efforts could be thwarted if drift or dispersal drive the community away from a desired state.…”

Section: Introductionmentioning

confidence: 99%

Dynamics and Functional Potential of Stormwater Microorganisms Colonizing Sand Filters

Fraser

Yue

Sakowski

et al. 2018

Water

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Stormwater management is increasingly relying on engineered infiltration systems (EIS) to reduce the volume and improve the quality of managed stormwater. Yet, EIS in the field will be colonized by a diverse array of environmental microorganisms that change the physiochemical properties of the EIS and provide a habitat for microorganisms with harmful or beneficial qualities. Understanding factors influencing the composition and stability of microbial communities could open up strategies for more efficient management of stormwater. Here, we analyzed the potential pathogenic and metabolic capabilities of stormwater microorganisms colonizing idealized EIS (i.e., sand columns) under laboratory conditions over time. The diversity of microbial communities was analyzed using 16S rRNA gene sequencing, and potential pathogens and denitrifying microbes were identified from taxonomic match to known species. Denitrification potential as determined by nosZ abundance was also assessed with quantitative polymerase chain reaction PCR. Our findings demonstrate that replicate microbial communities colonizing sand columns change in a similar way over time, distinct from control columns and the source community. Potential pathogens were initially more abundant on the columns than in the stormwater but returned to background levels by 24 days after inoculation. The conditions within sand columns select for potential denitrifying microorganisms, some of which were also potential pathogens. These results demonstrate that a diverse suite of stormwater microorganisms colonize sand filters, including a transient population of potential pathogens and denitrifiers. Manipulating the inoculating microbial community of EIS could prove an effective mechanism for changing both potential pathogens and denitrifying bacteria.

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“…The diversity and composition of the microorganisms in biosand filters have been characterized across a broad range of operating conditions. Most previous work on the microbial communities in biosand filters has focused on continuously operated systems representative of municipal-scale systems (5,8,13,(21)(22)(23)(24)(25), while only limited work focused on intermittently operated filters, typical of household-scale systems (26)(27)(28). This gap in our knowledge of the microbial communities in intermittently operated biosand filters is important given that many intermittently operated filters are implemented in conditions with less monitoring and often without posttreatment disinfection steps (2).…”

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confidence: 99%

“…Haig et al (29) showed that similar microbial communities developed in both lab-and full-scale filters continuously operated with the same source water. Other studies have highlighted the importance of filter medium type for community diversity and filter performance (21,23). These studies have found Planctomycetes, Bacteriodetes, Alphaproteobacteria, and Betaproteobacteria to be the most abundant bacterial taxa in drinking water filtration systems (8,(21)(22)(23)(24)(25)29).…”

mentioning

confidence: 99%

“…Other studies have highlighted the importance of filter medium type for community diversity and filter performance (21,23). These studies have found Planctomycetes, Bacteriodetes, Alphaproteobacteria, and Betaproteobacteria to be the most abundant bacterial taxa in drinking water filtration systems (8,(21)(22)(23)(24)(25)29). While these studies have provided much-needed insight into which microorganisms are found in filtration systems, we lack information about how key operational decisions, including start-up time and source water inputs, impact filter performance and microbial community composition changes over time in intermittently operated household filters.…”

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confidence: 99%

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Microbial Dynamics of Biosand Filters and Contributions of the Microbial Food Web to Effective Treatment of Wastewater-Impacted Water Sources

Webster

Fierer

2019

Appl Environ Microbiol

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Biosand filtration systems are widely used for drinking water treatment, from household-level, intermittently operated filters to large-scale continuous municipal systems. While it is well-established that microbial activity within the filter is essential for the removal of potential pathogens and other contaminants, the microbial ecology of these systems and how microbial succession relates to their performance remain poorly resolved. We determined how different source waters influence the composition, temporal dynamics, and performance of microbial communities in intermittently operated biosand filters. We operated lab-scale biosand filters, adding daily inputs from two contrasting water sources with differing nutrient concentrations and found that total coliform removal increased and became less variable after 4 weeks, regardless of water source. Total effluent biomass was also lower than total influent biomass for both water sources. Bacterial community composition, assessed via cultivation-independent DNA sequencing, varied by water source, sample type (influent, effluent, or sand), and time. Despite these differences, we identified specific taxa that were consistently removed, including common aquatic and wastewater bacteria. In contrast, taxa consistently more abundant in the sand and effluent included predatory, intracellular, and symbiotic bacteria. IMPORTANCE Although microbial activities are known to contribute to the effectiveness of biosand filtration for drinking water treatment, we have a limited understanding of what microbial groups are most effectively removed, colonize the sand, or make it through the filter. This study tracked the microbial communities in the influent, sand, and effluent of lab-scale, intermittently operated biosand filters over 8 weeks. These results represent the most detailed and time-resolved investigation of the microbial communities in biosand filters typical of those implemented at the household level in many developing countries. We show the importance of the microbial food web in biosand filtration, and we identified taxa that are preferentially removed from wastewater-impacted water sources. We found consistent patterns in filter effectiveness from source waters with differing nutrient loads and, likewise, identified specific bacterial taxa that were consistently more abundant in effluent waters, taxa that are important targets for further study and posttreatment.

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Medium shapes the microbial community of water filters with implications for effluent quality

Cited by 85 publications

References 37 publications

Flow-cytometric quantification of microbial cells on sand from water biofilters

Flow-cytometric quantification of microbial cells on sand from water biofilters

Dynamics and Functional Potential of Stormwater Microorganisms Colonizing Sand Filters

Microbial Dynamics of Biosand Filters and Contributions of the Microbial Food Web to Effective Treatment of Wastewater-Impacted Water Sources

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