Isolation of Aerobic Denitrification Bacteria and Denitrifying Character of BAF Bioreactor

For the content of total nitrogen in the effluent of BAF reactor significantly declining,by using the plate dilution method and the culture medium of acid-base indicator,two bacterial strains N1 and H1 screened from the biofilm of BAF reactor are found capable of aerobic denitrification.The denitrifying capability of the strains is studied in batch culture under aerobic conditions.The results show that there are aerobic denitrifying bacteria in the biofilm of BAF reactor,and the process of denitrification mainly takes place in log phases.According to the morphologic observation and physiological biochemistry tests,strains N1 and H1 are identified as Pseudomonas.On the basis of analyzing the impact factors,it is found that the main factors affecting aerobic denitrification by strains N1 and H1 are bacteria dosage,temperature,initial pH,C/N ratio and so on.The optimum operation of denitrification for strains N1 and H1 are bacteria dosage 5% and 10%;temperature 30 ℃ and 25 ℃;initial pH value 6.0;C/N ratio(mole ratio) 12.0:1 and 4.6:1,respectively.The study serves as a theoretical and technical reference for short-cut simultaneous nitrification and denitrification in BAF reactor.