Water crises are predicted to be amongst the risks of highest concern for
the next ten years, due to availability, accessibility, quality and management
issues. Knowledge of the microbial communities indigenous to drinking water is
essential for treatment and distribution process control, risk assessment and
infrastructure design. Drinking water distribution systems (DWDSs) ideally
should deliver to the consumer water of the same microbial quality as that
leaving a treatment plant (“biologically stable” according to WHO). At the start
of this Ph.D. program water microbiology comprised conventional culturedependent
methods, and no studies were available on microbial communities
from source to tap.
A method combining 16S rRNA gene pyrosequencing with flow
cytometry was developed to accurately detect, characterize, and enumerate the
microorganisms found in a water sample. Studies were conducted in seven fullscale
Dutch DWDSs which transport low-AOC water without disinfectant
residuals, produced from fresh water applying conventional treatment. Full-scale
studies were also conducted at the desalination plant and DWDS of KAUST,
Saudi Arabia where drinking water is produced from seawater applying RO
membrane treatment and then transported with chlorine residual. Furthermore,
biological stability was evaluated in a wastewater reuse application in the
Netherlands.
When low-AOC water was distributed without disinfectant residuals,
greater bacterial richness was detected in the networks, however, temporal and
spatial variations in the bacterial community were insignificant and a substantial
fraction of the microbiome was still shared between the treated and transported
water. This shared fraction was lower in the system transporting water with
chlorine residual, where the eukaryotic community changed with residence time.
The core microbiome was characterized and dominant members varied between
the two systems. Biofilm and deposit-associated communities were found to
drive tap water microbiology regardless of water source and treatment scheme.
Network flushing was found to be a simple method to assess water
microbiology. Biological stability was not associated with safety. The biological
stability concept needs to be revised and quantified. Further research is needed
to understand microbial functions and processes, how water communities affect
the human microbiome, and what the “drinking” water microbiome is like in
undeveloped countries. / The research presented in this doctoral dissertation was financially supported by and conducted in collaboration with Delft University of Technology (TU Delft) and Evides Waterbedrijf in the Netherlands.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/630222 |
| Date | 11 1900 |
| Creators | El-Chakhtoura, Joline |
| Contributors | Vrouwenvelder, Johannes S., Biological and Environmental Sciences and Engineering (BESE) Division, Saikaly, Pascal, Loosdrecht, Mark van, Stenchikov, Georgiy L. |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Rights | 2019-12-09, At the time of archiving, the student author of this dissertation opted to temporarily restrict access to it. The full text of this dissertation became available to the public after the expiration of the embargo on 2019-12-09. |
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