[Comparison study on phosphorus removal between single-stage oxic process and anaerobic/aerobic process].

To compare the efficiency of phosphorus removal between anaerobic/aerobic process (SBR1) and single-stage oxic process (SBR2), two SBRs were conducted using acetate as the sole carbon source which is the most extensive substrate in municipal wastewater. The results obtained from three months experiment showed that the phosphorus removal efficiency and the TP removed on a unit MLSS were 91.72%, 3.23 mg x g(-1) (SBR1)and 71.70%, 2.91 mg x g(-1) (SBR2) respectively during steady operation. The further study found that a significant increase of PHA associated with an decrease of glycogen in SBR1 while a significant synthesis of PHA increased with the accumulation of glycogen in SBR2, indicating glycogen was not essential for the synthesis of PHA in single-stage oxic process. Furthermore, obvious phosphorus release was observed in both SBRs during idle period, but the content of phosphorus released in SBR2 (13.28 mg x L(-1)) was significantly higher than that in SBR1 (2.6 mg x L(-1)). The possible reason for SBR1 and SBR2 exhibited different phosphorus removal efficiencies was that microorganisms in both SBRs had different cyclic storage and consumption process of energy storages during metabolic process.