Page 23 - University of Pretoria Research Review 2017

Foreword
Introductory Messages
DEVELOPMENT AND CHANGE
Water
Microbial contamination of drinking water
Fanus Venter, Rand Water Chair in Water Microbiology, Department of Biochemistry, Genetics and Microbiology
PEOPLE AND CONTEXTS
HEALTH AND WELL-BEING
PLANET AND SUSTAINABILITY
Awards
Lead Researchers
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The most common and widespread health risk associated with drinking water is microbial contamination. Of particular concern is contamination associated with major urban systems, as this has the potential to affect large numbers of people.
Water utilities serving urban communities use a multiple barrier approach to minimise the risk to consumers. These barriers include effective treatment processes to remove potential water-borne pathogens, and measures to ensure the biological stability and safety of the drinking water in the distribution process.
Over the past five years, Fanus Venter, Professor
in the Department of Biochemistry, Genetics and Microbiology, and the Rand Water Chair in Water Microbiology, has studied the microbial community and interactions within water treatment and distribution networks with his research team, to develop a better understanding of the microbial ecology of these urban water systems. Funding from Rand Water, and from
the Water Research Commission and the Department of Trade and Industry in South Africa, has supported the research undertaken, as well as collaboration
with Professor Ameet Pinto from the Northeastern University, Boston (US).
A recent paper published by the research group in the journal Water Research highlights the findings of a two-year study that focused on the microbial dynamics within an urban water distribution system in Gauteng. The study clearly demonstrated that disinfection, chlorination and subsequent chloramination are the main drivers shaping the microbial community in the water system, and that other physiochemical and environmental factors had a limited impact.
Developments in the field of next-generation genome sequencing have enabled microbiologists rapidly to determine the composition of the microbial community in a sample. By determining the sequences of the
16S rRNA region present in all bacteria, a detailed inventory of the bacterial species present in a water sample can be obtained. It also provides data on their relative abundance at the time of sampling. Based on the current research, the study concluded that the health risks posed are not of great concern as potential pathogens were only detected sporadically and at low abundances, in comparison with the total drinking water microbial community.
Based on their investigation of several treatment and distribution systems, the group demonstrated that these systems differed markedly from one another, and therefore that a universal model to predict the microbial community of the water supplied to the consumer would be difficult to achieve. The study also confirmed that understanding the ecology and the factors that shape the drinking water microbiome is essential in developing and implementing appropriate measures to manage the microbial community quality and associated health risks.