Denitrification Characteristics And Application Of Aerobic Denitrifier

In recent years,the large amount of nitrogen-containing wastewater has become an important factor in the eutrophication of water bodies.The removal of nitrogen has become a hot issue in the prevention and control of water pollution.Aerobic denitrifying bacteria have become the research focus and main direction of wast ewater denitrification because of its aerobic nitrification and heterotrophic nitrification,rapid growth and strong environmental adaptability.In this paper,a high-efficiency heterotrophic nitrification-aerobic denitrification strain was screened from activated sludge from Changping Sewage Treatment Plant,and its nitrogen removal characteristics and environmental factors were investigated for heterotrophic nitrogen removal.In addition,in order to provide technical guidance for its future practical application the application in petrochemical wastewater of composite microbial flora was studied.The main findings are as follows:(1)The strain was identified as Pseudomonas by morphological observation,physiological and biochemical experiments and 16 S r RNA sequence analysis.(2)In the experimental water samples with NH4+-N?NO3--N and NO2--N as the only nitrogen sources,the removal rates of NH4+-N?NO3--N and NO2--N were 95.39%,96.92% and 92.38% in 32 h.Strain HX4 has significant heterotrophic nitrification and aerobic denitrification performance;when mixed NH4+-N and NO3--N,NH4+-N and NO2--N were nitrogen sources,the removal rates of NH4+-N and NO3--N,NH4+-N and NO2--N were 92.32% and 82.33%,85.59% and 85.73% in 32 h,Strain HX4 has good Performance of simultaneous nitrification and denitrification.(3)Through the single factor experiment of carbon source,C/N,initial p H,temperature and rotation speed and BBD response surface design test,the optimal conditions for heterotrophic nitrification and denitrification of strain HX4 were as follows: C/N of 11.605,the rotation speed of 132.467 r/min,temperature of 31.328 °C and initial p H of 7.809.Under this condition,the removal rate of TN is 90.87%,and the order of influence of p H value,carbon-nitrogen ratio,temperature and rotation speed on the removal rate of heterotrophic nitrification TN is Initial p H > carbon to nitrogen ratio > temperature > speed.(4)The high-efficiency heterotrophic nitrification-aerobic denitrification strain of the primary screening was combined with HX4 to construct a high-efficiency denitrifying bacterial group combination 7(HX4+ HX6+ HX9).The composite wastewater group 7 was used to treat the petrochemical wastewater.After the carbon source was supplemented,the removal rates of TN and NH4+-N were 83.69% and 90.25%,respectively.