Synergistic phosphorus removal mechanism of Tetrasphaera enrichment in a micro-pressure swirl reactor

To investigate the effect of Tetrasphaera’s enrichment on phosphorus removal mechanism, three micro-pressure swirl reactor (MPSR) groups were used to experiment on sewage treatment under different SRT (17.2, 50.8, and 68.2 d). Results showed that Tetrasphaera enrichment in the MPSR system was promoted by extending the SRT. After extending the SRT from 17.2 to 68.2 d, the relative abundance of Tetrasphaera increased from 3.1% to 12.1%, and the TP removal efficiency maintained above 92%. The internal circulation results indicated that after extending the SRT, glycogen and polyhydroxybutyrate were co-synthesized during the anaerobic stage, which enhanced the driving force of nutrient removal. Analysis of the microbial composition and functional gene prediction indicated that efficient phosphorus removal can be attributed to the enrichment of Tetrasphaera at long SRT. Overall, the synergistic mechanisms of Tetrasphaera in the organic matter degradation and phosphorus removal processes were integrated into the MPSR.