Study On The Nitrogen Removal Efficiency Of Domestic Sewage Enhanced By SBR Simultaneous Nitrification And Denitrification

With the sharpening of the water environment pollution and the lack of water resources.The people's environmentawareness is increasing.For nitrogen and phosphorus the standard of sewage discharge is becoming more and more stringent.Due to the limitation of autotrophic bacteria,the traditional biological denitrification method has a long starting time and high energy consumption.The process of simultaneous nitrification and denitrification has a large number of advantages.Such as simple operation,saving time of pollutant removal,and greatly reducing the cost of investment and operation.In this study,domestic sewage was taken as the research object.The effect that the structural modification of SBR simultaneous nitrification and denitrification?SND?reactor on the removal efficiency of pollutants was studied.The role of the EPS in the denitrification procedure was analyzed.In order to further improve the efficiency,which simultaneous nitrification denitrification and denitrification of SBR.Isolation and screening of the aerobic denitrifying bacteria with high efficiency of denitrification.On the basis of investigating that the factors affecting the conversion effect of common nitrogen.For exploration the aerobic denitrification strain strengthening the denitrification effect on simultaneous nitrification and denitrification in the chemical SBR reactor.It provides a basis for the application of aerobic denitrifying bacteria in SBR simultaneous nitrification denitrification and denitrification.The structure of the reactor affects the removal of pollutants.The changes in the structure of the reactor have great influence on the removal of COD,ammonia nitrogen and total nitrogen.When the distance was adjusted from 4cm to 5cm and 6cm,the removal rate of COD decreased from 83.10%to 90.61%to 81.36%.The removal rate of NH₄⁺-N decreased from 89.34%to97.55%after 92.95%.The removal rates of TN were 72.98%,79.21%and 71.70%.The changes in the structure of the reactor have little effect which on the change of pH and the removal of PO₄^3--P.The pH value of the effluent is 8.0-9.0,The removal rate of PO₄^3--P is above 95%.The activated sludge EPS contains a large number of PN and PS,and the content of PS and PN is 35.52 and 69.63 mg/g.The results of stratified analysis showed that the proportion of TB-EPS was much more,of which PS and PN accounted for 93.11%and 97.41%of the total content of EPS PN and PS,respectively.The 4 aerobic denitrifying bacteria isolated from the experiment.They can achieve different degrees of transformation and utilization of ammonia nitrogen,nitrite nitrogen and nitrate nitrogen.The most suitable environmental factors of the dominant strain A4 determine the C/N ratio of 10:1?glucose as carbon source?,pH 6.5,and temperature at 30?.The addition of aerobic denitrification bacteria suspension has little effect on the removal of ammonia nitrogen,but it has great influence on the removal of COD and TN.When the volume ratio of bacterial solution was 2%and 6%,the removal rate of ammonia nitrogen was over 95%.Respectively,the average removal rate of COD increased by 3.69%and 3.86%,and the average removal rate of total nitrogen increased by 4.96%and 11.77%.