Experimental Study On Isolation And Purification Performance Of NO_X Of An Aerobic Denitrifier

Nitrogen oxides （NO_x） are one of the major sources caused air pollution,a largenumber of emissions will seriously affect the whole ecological environment and threathuman health and social development.Controlling and treating NO_x pollution withBiological method has been became an hotspots,with low-cost,no secondary pollutionand so on.In the experiment,aerobic denitrifier2of the high denitrification capacity wasscreened and cultivated from the activated sludge of sewage treatment plants.Anorthogonal on the growth and denitrification conditions were applied to optimizebecause of low denitrification capacity of strain2.The results showed that strain of2within24h denitrification capacity increased to95.58%from65.80%of thepre-optimization when the pH is7.0,the C/N increased to5,carbon source is glucose, therotation speed is160r/min.Calculated by orthogonal method to determine the bestconditions of denitrification was glucose as carbon source,COD/N ratio of8,pH of7.0,180rpm.Trickling filter biofilm used activated carbon as a filler for the NO_x purificationperformance of experimental study.The results showed that the optimum combination ofmedium containing KNO₃liquid nitrogen biofilm formation,and then contain ofNO_X,KNO₃in gas liquid nitrogenthe optimum combination of medium joint biofilmformation, biofilm formation can be completed within10days.NO_x degradation rateremained more than92.48%when the amount of spray was0.32L/h,the circulating fluidpH was7.0,temperature was30°C and the concentration of NO_x inlet was415.22¹605.19mg/m³.Under these experimental conditions,when the NO_x inletconcentration was345²135mg/m³,the minimum gas residence time t_s appropriate to take the52s. NO_x purification efficiency increases as the layers of packing heightincrease.NO_x inlet concentrations return to the initial concentration from1497.79mg/m³after three mutations （6207.51、3204.58、3653.74mg/m³）,Performance ofthe biofilter under shock loading conditions was strong and the NO_x removal rate still remainedat92.32%⁹5.96%.Slowly restoring to the former NO_x inlet concentration of outage,the systems can be restored to a high purification ability in5h,10h,and the NO_x removalrate was more than87.41%after stopping running at2days and4days.