Abstract:

The A/A sequencing batch reactor(SBR)was used to enrich denitrifying and phosphorus accumulating bacteria(DPB).Denitrifying and phosphorus accumulating tests were performed by using acetic acid and glucose as substrate.The metabolic mechanism and change of phosphorus/nitrate/COD in water and polyhydroxyalkanoates(PHA)/glycogen in sludge were studied.The release of poly-phosphate would control the combination of PHA.At the anoxic stage breakdown of PHA was used as carbon source to denitrify nitrate, and the adenosine triphosphate(ATP)thus generated provided energy for accumulating phosphorus.So it is important to track the change of PHA, not COD when the denitrifying and phosphorus accumulating process was studied.When glucose was used as substrate, fermented bacteria broke down glucose into volatile organic acid of small molecules, then non-fermented bacteria could play a role fully.At the anaerobic stage, 85% energy came from the release of phosphorus, 15% energy came from the fermentation of glycogen.At the anoxic stage, 85% PHA breakdown was used to accumulate  phosphorus, 15% was converted into glycogen.The metabolic mechanism could be simplified.