Behavior of total phosphorus removal in an intelligent controlled sequencing batch biofilm reactor for municipal wastewater treatment

► Phosphorus is successfully removed in sequencing batch biofilm reactor (SBBR). ► SBBR controlled by an intelligent control system (ICS) performs better. ► No significant anaerobic phosphorus release is observed in ICS-SBBR. ► Polyhydroxyalkanoates (PHAs) is the main energy source. ► Biochemical metabolism of phosphorus removal in ICS-SBBR is elucidated. The behavior of total phosphorus removal was investigated in present study in sequencing batch biofilm reactor (SBBR) controlled by an intelligent control system (ICS) with less energy consumption for municipal wastewater treatment. Stable total phosphorus (TP) removal efficiency of 93.9±2.2% was achieved in comparison to that of 93.3±2.5% in a conventional timer control system (TCS-SBBR). Significant anaerobic phosphorus release was not observed in ICS-SBBR, which was unlike the conventional TCS-SBBR. Moreover, lower accumulations/transformations of polyhydroxyalkanoates (PHAs) and higher transformation of glycogen occurred in the ICS-SBBR, indicating that PHAs was the main energy source while glycogen played a supporting role when PHAs were inadequate, which was different from the traditional mechanism of biological phosphorus removal in TCS-SBBR. The possible biochemical metabolism of phosphorus removal in ICS-SBBR was also elucidated.