Isolation And Identification Of A Heterotrophic Nitrification-Aerobic Denitrification Bacterium Based On Rpf And Research Of High Ammonia Nitrogen Wastewater Treatment At Low Do

Our country’s economy has got rapid development and the living strandards are getting better as the development of industry and agriculture, but as the same time, the environment is getting worse, and the water eutrophication caused by nitrogen pollution has been one of the most serious problems in our world. The ways to remove nitrogen include physico-chemical, biochemical, short nitrification and denitrification, biofilm-SBR and so on.The selection of bacteria and growth condition are the key to the removal of nitrogen. the biological is one of the most cost-effective way for ammonia degradation, and the bacteria is a key to the effect. This thesis focused on the resuscitation and isolation of VBNC state bacteria from soil samples based on the Rpf (resuscitation promoting factor). the rpf gene was cloned and heteologous expressed in Escherichia coli. A bacterium ZB612 with heterotrophic nitrification-aerobic denitrification was isolated from soil sample around leachate regulating pool of Hangzhou Tianziling waste landfill. The strain ZB612 was preliminary identified as Rhizobium sp. by morphology and 16S rDNA homology analysis. We subsequent studied its denitrification ability, the results showed that the ammonia nitrogen removal efficiency reached 90% in the heterotrophic nitrification medium with initial ammonia nitrogen concentration of 100 mg/L. Meanwhile, the obvious accumulation of nitrate-N and nitrite-N did not appear, which has the characteristics of simultaneous nitrification and denitrification (SND). In nitrates denitrification system, the nitrate nitrogen removal efficiency could reach 60%. In addition, we also investigated the effect of four factors(including temperature. pH, carbon nitrogen ratio and carbon source) on denitrification efficienc of the strain ZB612, The optimum denitrification conditions were found to be as follows: temperature of 30℃, the initial pH of 7, C/N ratio of 8, the optimal carbon resource was glucose. These experimental results provide the theoretical basis for practical application of simultaneous nitrification and denitrification in wastewater treatment.In this research we developed one kind of novel wastewater treatment system combing rotating biological contactors with SBR process to investigate its treatment effect. The result showed that the novel wastewater treatment system can degrade COD and TN better than sewage treatment system before. This system can partially realise simultaneous nitrification and denitrification, with little trace NO3-, NO2-, and pH was stable.