Isolation And Characterization Of The Bio-reduction Strains Of Fe~?(EDTA) And Fe~?(EDTA)-NO In BioDeNO_x

Recently,the nitrogen pollution has been a increasing serious problems,which included not only NO3--N,NO2--N and NH4+-N in the water but also NOx in the gas.Accordingly,how to remove reactive nitrogen had became a research hotspots.Chemical absorption combied with biological reduction process(BioDeNOx)was used to treat NOx.It had many advantages such as high removal efficiency,low secondary pollution,acceptable running cost and so on,which had attracted more and more attention.The key problem was how to bioreduce the main two components of the absorption process in liquid as Fe?(EDTA)-NO and Fe?(EDTA).At the same time,reactive nitrogen of absorption existed with NO3--N,NO2--N and NH4+-N.In addition,the temperature of the flue gas after wet desulfurization was varied from 50 ? to 60 ?.Therefore,the Fe?(EDTA)reducing bacteria and Fen(EDTA)-NO reducing bacteria were islated from BioDeNOx under 55?.By optimizing the medium,and it got the best reduction performance of the microorganism.Further,it studied the nitrification and denitrification of the two strains.(1)A Fe?(EDTA)reducing bacteria was islated from BioDeNOx under 55 ?.It was proved to be Cram-negative,rod-shaped,and also formed yellowish colonies on the medium,roughness surface,opaque,neat edge,raised,inviscid,spore,and no flagella.It was indentificated as the Bacillus subtilis according to morphological and physiological biochemical characteristics and the 16S rRNA sequence analysis.(2)The performance of strain HH was optimized for Fe?(EDTA)reduction conditions.The results demonstrated that the sodium acetate is the most suitable carbon source.The optimal NH4Cl adding amount is 100mg·L-1.The optimal pH range was 7.2?7.7 for Fe?(EDTA)reduction.Fem(EDTA)reduction rate decreased with the presence of SO32-.Moreover,the inhibitory effect was proportional to the concentrations of SO32-in the media.(3)The investigation of nitrification performance of the strain HH showed that glucose was the best carbon source.The higher the concentration of NH4-N was,the lower the removal efficiency of the strain was.While the pH varied from 6.5 to 8.5,the strain HH could survive,but its growth and removal efficiency were good in the neutral environment.(4)A Fen(EDTA)-NO reducing bacteria was islated from BioDeNOx under 55 ?.It was proved to be Cram-negative,rod-shaped,and also formed white colonies on the medium,opaque,smooth surface,neat edge,inviscid,spore.It was indentificated as the Anoxybacillus contaminans according to morphological and physiological biochemical characteristics and the 16S rRNA sequence analysis.(5)The Fe?(EDTA)-NO reducing performance of the strain HA was investigated.The results demonstrated that the sodium acetate was the most suitable carbon source and the optimal sodium acetate adding amount was 3000 mg·L-1.The most suitable pH was 7.0 and the inoculum amount was 2.5%.(6)The results showed that the training time of the strain HA in nitrification medium and denitrification medium were 8 hours and 16 hours respectively.The strain HA had the better denitrification performance with glucose and the temperature 55?.The accumulation of nitrate nitrogen climbed up and denitrification efficiency decreased while the denitrification rate accelerated at a certain degree.