Metagenomic Profile of Bacterial Community and Phage in Domestic Wastewater Treatment Plant

For a better understanding of the microbial community and associated phage abundance in domestic wastewater treatment system, this study did a metagenomics profiling of bacterial community and phage in activated sludge process and chlorination system. The Phylum Proteobacteria is the most abundant group in all streams but the most abundant subgroups of this is different between the raw wastewater and those in activated sludge. The former comprises gamma and epsilon Proteobacteria whereas activated sludge consist of delta and alpha Proteobacteria. The other less abundant Phylum in raw domestic wastewater are Firmicutes, Bacteroidetes and Actinobacteria. The group Delta Proteobacteria are most susceptible to chlorination. Rhodocyclaceae (of beta Proteobacteria) and the family Oxalobacteraceae and Comamonadaceae are also among the most affected by chlorination. Rhodocylaceae and Procabacteriaceae are resistant to chlorine treatment. Rhodocyclaceae are well known polyphosphate accumulating bacteria, which are also responsible for EBPR and their viability is high in activated sludge. On virome profiling, in the influent, the crAss phage, which is commonly found in fecal bacteria, predicted to the host Bacteroidetes, was dominant. The other phage such as Pseudomonas, Escherichia coli, Aeromonas and Lactococcus may also derived from the human gut. EBPR (enhanced biological phosphate removal )- associated phage were observed in all samples except influent. As their hosts, phosphate accumulating bacteria were present in activated sludge.