PHOSPHORUS UPTAKE AND DENITRIFICATION BY THE DENITRIFYING PHOSPHORUS REMOVING BACTERIA UNDER ANOXIC PHASE

摘要

The denitrification activity of DPB at the anoxic stage was investigated by analyzing organic and nitrogen balances at the selected internal recycle ratios. Moreover, for verification of the microbial community, the identification of microbiology accomplished using the PCR-DGGE method. As the internal recycle ratio increased 1 to 3, the amounts of anoxic phosphorus uptake and nitrate reduction rate increased due to the improved activity of DPBs in the anoxic state. In batch test, the nitrate removalefficiencies by denitrifiers and dephosphatation by DPBs were 76 % and 24 % of total nitrate removal efficiency, respectively. Most PAO species from the sludge using synthetic wastewater were affiliated with the beta subclass of the Proteobacteria. The species detected belonged to two genera:Dechloromonas and Rhodocyclus. However, Acinetobacter sp., Aeromonas sp. and Pseudomonas sp.,which historically have been considered dominant in phosphorus removing sludge communities, were not detected.