Effect of aeration modes on simultaneous nitrogen and phosphorus removal and microbial community in a continuous flow reactor with granules.

In this study, a continuous flow reactor with simultaneous nitrification, denitrification and phosphorus removal (SNDPR) granular sludge was operated in the continuous aeration (CA) and intermittent aeration (IA) modes to examine the effect of aeration on the performance of continuous-flow system. Then the experimental results showed that the IA mode (4 h aeration and 1 h non-aeration) could improve the simultaneous nitrogen and phosphorus removal and the settleability of granules in continuous flow system. Results of high-throughput pyrosequencing illustrated that the methanogens, AOA, ANAMMOX, DNB, denitrifying polyphosphate-accumulating organisms (DPAOs) were the important participant of simultaneous biological nutrients removal (SBNR), meanwhile, the IA mode could effectively inhibit the growth of filamentous microorganisms (Thiothrix and Acinetobacter). Finally, a conceptual model of the SNDPR granular microbial ecosystem under IA mode was proposed as a base for analyzing the mechanism of simultaneous nutrient removal in continuous flow system.