Removal Effect of Phosphorus and Population Structure of Phosphorus Accumulating Organisms in HA-A/A-MCO Sludge Reduction Process

The HA-A/A-MCO process combines phosphorous and nitrogen removal and sludge reduction.When the influent TP was 8 to 12 mg/L,the effluent TP was only 0.44 mg/L,which could satisfy the first level A criteria specified in GB 18918-2002.Phosphorus accumulating organisms(PAOs) showed strong excess phosphorus uptake potential.When PAOs released 1 mg P,they could absorb 2.8 mg P.However,the system realized phosphorus removal through eliminating anaerobic phosphorous accumulating sewage.As a result,phosphorous was removed before aerobic phosphorus uptake process and the excess phosphorus uptake ability of PAOs was not effectively used.By using bacterial pure culture technique,five strains of PAOs with typical phosphorus uptake and phosphorus release performance were separated from the HA-A/A-MCO process.16S rDNA PCR and sequences analysis of the five PAOs strains indicated that Acinetobacter sp.and Lampropedia sp.dominated in the course of anaerobic phosphorus release.Devosia sp.and Bdellovibrio sp.occurred in aerobic tank,which were the predominant bacteria in the course of aerobic phosphorus uptake.Uncultured Bacterium was detected in anoxic tank.