Study on the Isolation Screening and Characteristic Identification of Denitrifying Phosphorus Removing Bacteria in Sequencing Batch Biofilm Reactor

The processes of denitrification and dephosphorization which were independent originally were integrated into Biological Denitrifying Phosphorus and removing process. It was widely considered a bright technology of biological phosphorus removal. According to the denitrifying phosphorus bacteria(DPB) principle, this paper aimed to isolate denitrifying phosphorus removing strains in Sequencing Batch Biofilm Reactor (SBBR), to identify their denitrification and phosphorus removing characteristics and to prove the exists of denitrifying phosphorus removing bacteria in SBBR. Adding polyurethane carriers in SBR, this study took nitrate as electronic acceptor, to investigate simultaneous denitrifying and excessive accumulating phosphorus under anaerobic--anoxic conditions. This experiment used dilution coating method and traditional flat plate scribing method to isolate denitrifying phosphorus removing bacteria, and also used metachromatic granules dyeing method and nitrate reducing test to identify the screening bacteria. The results showed that three kinds of high-performance strains were isolated from activated sludge, which can be capable of denitrification and phosphorus removing efficacy. They all had metachromatic granules, and the Gram´s dyeing was all feminine. The removal rates of nitrate strains were 76.12%, 78.76% and 62.68% respectively. It was concluded that there were abundant denitrifying phosphorus removing bacteria in SBBR, which can be enriched isolated and identified through streak plate, metachromatic granules dyeing and nitrate reduction test.