Biogeography and Assembly of Microbial Communities in Wastewater Treatment Plants in China

Scientific
understanding of microbial
biogeography and assembly is lacking for activated
sludge microbial communities, even though the diversity of microbial
communities in wastewater treatment plants (WWTPs) is thought to have
a direct influence on system performance. Here, utilizing large-scale
16S rRNA gene data generated from 211 activated sludge samples collected
from 15 cities across China, we show activated sludge microbes, whose
growth and metabolism can be regulated followed with the metabolic
theory of ecology with an apparent Ea value (apparent activation energy)
of 0.08 eV. WWTPs at a lower latitude tend to harbor a more diverse
array of microorganisms. In agreement with the general understanding,
the activated sludge microbial assembly was mainly driven by deterministic
processes and the mean annual temperature was identified as the most
important factor affecting the microbial community structure. The
treatment process types with similar microbial growth types and functions
had a distinct impact on the activated sludge microbial community
structure only when WWTPs were located near each other and received
similar influent. Overall, these findings provide us with a deeper
understanding of activated sludge microbial communities from an ecological
perspective. Moreover, these findings suggest that, for a given set
of performance characteristics (e.g., combined nitrification, denitrification,
and phosphorus removal), it may be difficult to employ common engineering
levers to control additional aspects of community structure due to
the influence of natural environmental factors.