Abstract: Two runs of experiments were carried out to obtain an understanding
of phosphorus release and uptake under the anaerobic condition and then the
aerobic condition respectively. Under anaerobic condition, it was found that
the extent of phosphorus release appeared to increase with the increase of the
initial organic loading rate when the initial organic loading rate was up to
0.1 gSCOD/gMLSS. When the initial organic loading rate was higher than 0.1
gSCOD/gMLSS, the amount of phosphorus release per unit mass of MLSS reached
nearly a same stationary value, and it seemed this is not affected by organic
loading rate when there is external available substrate remained. In addition,
the effect of NOx-N on the phosphorus release and uptake was also investigated,
it was proved that the denitrifiers has an advantage over polyphosphate
accumulating bacteria in competition for organic substrate under anoxic
condition. Therefore, the existence of NOx-N is disadvantageous to the
phosphorus release. Based upon the above investigations, the process
configuration of membrane bioreactor (MBR) in combination with anaerobic phase
was proposed to enhance the removal of phosphorus in treating domestic
wastewater. During the experimental period of four months, average removals of
92.50%, 84.25%, 100%, 94.09% and 85.33% were achieved for COD, TP, SS,
NH_3-N and TN respectively.
