Study On The Mechanism Of N 2 O Release During Simultaneous Nitrification And Denitrification

Traditional biological nitrogen removal techniques have many disadvantages when dealing with the wastewater,such as complex process,energy consumption and adding extra carbon source.The process of simultaneous nitrification and denitrification has a wonderful treatment effect,and has the advantages of low energy consumption,however,the process will produce a large number of Nitrous Oxide?N₂O?,Biological sewage treatment is an important source of N₂ O release,which makes up to a quarter of the total global N₂ O release.As an important greenhouse gas,is bound to accelerate the greenhouse effect,it also damages the ozone layer,promotes the formation of acid rain etc.Therefore,it has important practical significance to study the mechanism of simultaneous nitrification and denitrification and the way of N₂ O release.In this paper,through the way of controling of the dissolved oxygen,the reaction condition are adjusted to realize simultaneous nitrification and denitrification process.Analyze the effct of pollutants removal during the SND process,and explore the pollutants migration and transformation process,understand the release of N₂ O in SND,and through the method of high-through put sequencing,the succession of microbial species in the main group of N₂ O release during the process of SND;by changing the influent,to explore the effects of different phosphorus load works on the SND and the release of N₂ O.The main conclusions are as follows:Though the SND process improves the total nitrogen and phosphorus removal ability,approximately 73% and 90% respectively,meanwhile it promotes the N₂ O release.And it mainly occurs on the aeration phase.Under the condition of low C/N ratio,denitrifying bacteria using intracellular storage of organic material as a carbon source for denitrification,the electron donor,denitrifying enzyme competition leads to the accumulation of N₂ O release a lot.Through high-through put sequencing analysis of microbial community structure related to the N₂ O release,in the process of microorganismm domesticated PAO gradually enrichment and become one of the dominant species.AOB content in the whole process is not high,but in the early days of domestication,the quantity of anammox bacteria is considerable.It is an important component of community structure,and plays an indispensable role in simultaneous nitrification and denitrification.Under high phosphorus content in water comes into system,the removal rate of TN improves and TP as well,during the process of N₂ O release decreases.Due to thecondition,the related microbial denitrification with PHB,eases the competition between denitrifying enzyme of electon donor.Under high phosphorus load by phosphorus accumulation a large number of enrichment,this alsois the important condition of competition between denitrifying enzyme of electron donor.Under high N₂ O release reduce.