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Advisor(s)
Abstract(s)
Disinfection processes aimat reducing the number of viable cells through the generation of damages in different
cellular structures and molecules. Since disinfection involves unspecific mechanisms, some microbial populationsmay
be selected due to resilience to treatment and/or to high post-treatment fitness. In this study, the bacterial
community composition of secondarily treated urban wastewater and of surface water collected in the
intake area of a drinking water treatment plant was compared before and 3-days after disinfection with ultraviolet
radiation, ozonation or photocatalytic ozonation. The aim was to assess the dynamics of the bacterial communities
during regrowth after disinfection.
In all the freshly collected samples, Proteobacteria and Bacteroidetes were the predominant phyla (40–50% and
20–30% of the reads, respectively). Surface water differed from wastewater mainly in the relative abundance
of Actinobacteria (17% and b5% of the reads, respectively). After 3-days storage at light and room temperature,
disinfected samples presented a shift of Gammaproteobacteria (from 8 to 10% to 33–65% of the reads) and
Betaproteobacteria (from 14 to 20% to 31–37% of the reads), irrespective of the type of water and disinfection process used. Genera such as Pseudomonas, Acinetobacter or Rheinheimera presented a selective advantage after
water disinfection. These variations were not observed in the non-disinfected controls. Given the ubiquity and
genome plasticity of these bacteria, the results obtained suggest that disinfection processes may have implications
on the microbiological quality of the disinfected water.
Description
Keywords
Ozonation UV radiation Photocatalytic ozonation Wastewater
Citation
BECERRA-CASTRO, Cristina; MACEDO, Gonçalo; SILVA, Adrian M.T. ; MANAIA, C. M.; NUNES, Olga C. - Proteobacteria become predominant during regrowth after water disinfection. Science of The Total Environment. ISSN 0048-9697. Vol. 573 (2016), p. 313–323