Isolation And Identification Of The Simultaneous Desulfurization And Denitrification Bacteria And Research On Its Characteristics Of Removal NO_x And SO₂ In The Flue Gas Biological Purifying Towers

Haze,which is mainly composed of SO2,NOx and respirable particulate matter,has become a major factor affecting human health.The removal rate of SO2 could reach 100%during the process of biological flue gas desulfurization and denitrification.However,the removal efficiency of NOx is not high because NO is insoluble in water.Therefore,to improve the biological removal efficiency of NO,NOx has been the focus of research.In order to improve the removal efficiency of NO and NOx,we isolated,purified and filtered two bacteria which are capable of simultaneous desulfurization and denitrification from the biofilm of the desulfurization tower.Through the morphological study,physiological and biochemical experiments and the molecul ar biology identification of the filtered bacteria,we identify the 5XSB Strain wit h high desulfurization and denitrification as Halomonas nitritophilus,and the 9X SB Strain as Pseudomonas fluorescens.Through physiological and biochemical experiments,we know that the isolated and purified Halomonas nitritophilus and Pseudomonas fluorescens have the capability of simultaneous desulfurization and denitrification:the two purified bacteria make the NO3-in culture medium as electron acceptor,which leads to the reducation of the NO3-,denitrification rate of two bacteria was respectively 72.2%and 69.9%,under the condition of 500 mg/L of NO3--N and 10 days of static culture,meanwhile,the blank control group was 18.5%;At the same time,the two purified bacteria make the S2O32-in culture medium as electron donor,which leads to the growth of SO42-,sulfate generation rate of two bacteria was respectively11.9%and 11.4%,under the condition of 2258 mg/L of S2O32-and 10 days of static culture,meanwhile,the blank control group was 5.1%.The optimal growth condition optimization experiment indicated:the optimum temperature of the Halomonas nitritophilus is 30?,the optimum pH is 8,and the optimum carbon source is sodium citrate;the optimum temperature of Pseudomonas fluorescens is 30?,the optimal pH is 7,and the optimum carbon source is sodium acetate.We expanded the two purified bacteria by optimum growth conditions and inoculated them to the Desulfurization tower and nitrogen removal tower at different time.after putting the purified Halomonas nitritophilus,the removal rate of NO and NOx was increased by 4.6%and 4.3%respectively on average.and the Pseudomonas fluorescens was 4.3%and 4.0%.The result shows that:the two purified bacteria having the capability of simultaneous desulfurization and denitrification can significantly improve the denitrification capacity of the the simultaneous desulfurization and denitrification system.The two purified bacteria are Heterotrophic bacteria;the appearance of the Halomonas nitritophilus in the system of desulfurization and denitrification indicates that the desulfurization tower has a higher salt concentration.Whether this will hinder the efficiency of desulfurization and denitrification will be further studied.The results of this study will provide a new way to improve the efficiency of biological flue gas denitrification and advance the process of industrialization greatly.