Identification of Wastewater Treatment Plant-Specific Microbial Markers Using 16S rRNA Sequencing

We collected 57 effluent samples for 16S rRNA v4 sequencing from six treatment plants in the Tampere region of Finland between 2016 and 2018. Characterising the microbiome revealed that although each plant had unique microbial profiles, their overall diversity and richness were similar. This provided a robust foundation for identifying plant-specific microbes. Using ANOVA-F for feature selection, we focused on the genus level due to its informative prevalence. Among various models tested, the Gaussian Naive Bayes model yielded the highest accuracy with the fewest relevant microbes. We identified nine bacterial genera and one archaeon, whose relative abundances predicted the origin of the effluent with 92% accuracy.