The metabolic activity of microorganisms is essential for the removal of nutrients, pollutants and pathogens from municipal wastewater. However the efficiency of this removal ‒ in terms of quantity, quality and rate ‒ depends on the complex and mutable interplay between biotic and a-biotic variables occurring in the treatment plant.
During the present study, three a-biotic variables were selected ‒ season, treatment stage and treatment-technology ‒ after hypothesizing that the microbial assemblages of Bacteria, Archaea and Eukarya would respond to them accordingly. A spatial-temporal analysis of the microbiome was conducted by next-generation DNA sequencing and the results were compared to the efficiency of removal of various nutrients and anthropogenic pollutants.
Multivariate analysis allowed the clustering of microbiome‒ and chemical‒ fingerprints, based on season, treatment stage and treatment-technology. Influents showed consistent profiles, irrespective of the a-biotic variables. Conversely microbiome and chemical fingerprints in later stages and across ‒seasons and ‒technologies were more erratic, with treatment stage and plant-design having a bigger effect on the community than season. Identifying the most important variables contributing to the establishment of particular biological assemblage may allow predicting the decay of pathogens, occurrence of beneficial taxa, their activity and, ultimately, the plant performance.