Integration of synchronous nitrification-denitrification in a single-stage biofilm reactor for phosphorus removal and enrichment

The biofilm reactor successfully achieved simultaneous nitrification, denitrification, and phosphorus enrichment under high dissolved oxygen conditions. The dynamic test in-situ and stoichiometric evaluations ex-situ combined the macro gene sequencing further recovered that DGAOs (Pseudoxanthomonas and Sulfuritalea et al.) were the dominant denitrifiers in the P enrichment system due to a series of denitrifying genes' high expression. That implied the DGAOs have a higher tolerance to high DO concentration, which was crucial to performing SND in the P enrichment system. These findings shed light on the positive roles of DGAOs in the denitrification process and lay an experimental basis for the development of a new feasible technical route for simultaneous N removal and P enrichment in a single stage system.