Study On The Efficiency Of Improved A/O Process In The Treatment Of Domestic Sewage

With the acceleration of the urbanization process,a large amount of domestic sewage is discharged into rivers without treatment or without meeting the standards,causing serious harm to the river’s ecological environment.Due to the fact that urban domestic sewage has large water volume,complex pollutant components,few organic carbon sources,and increasingly strict national requirements,the development of efficient,stable,and practical urban domestic sewage treatment technology is one of the current research priorities in the field of urban domestic sewage control.This article intends to use the improved A/O process to treat urban domestic sewage.This improved A/O process improves and optimizes the sludge return and nitrification liquid return systems in the traditional A/O process: First,the sludge return line is connected to the aerobic tank head,and the sludge is directly returned to aerobic Tank,to avoid the adverse effect of the anoxic tank on the nitrifying bacteria;the second is to change the nitrification liquid from internal reflux to external reflux,and return the nitrification liquid of the overflow weir of the second settling tank to the anoxic tank,the purpose is to optimize the anoxic tank And the living environment of microorganisms in the aerobic tank,to avoid the increase of dissolved oxygen in the anoxic tank due to the backflow of the nitrification liquid.10 days after the sludge inoculation in the rapid start-up phase of the reactor,the reactor had a higher removal rate of COD,TN and NH3-N and the operation was stable.In order to investigate the influencing factors of the improved A/O process,the nitrogen removal efficiency of the reactor was explored by changing the influent HRT,C/N ratio and nitrate reflux ratio.The results showed that when the hydraulic retention time was equal to 17.5h,the nitrate reflux When the ratio is equal to 200% and the carbon-nitrogen ratio is equal to 10:1,the improved A/O process system has a better treatment effect on sewage.At this time,the removal rate of COD by the system is equal to 97.69%,and the removal rate of ammonia and nitrogen is equal to 90.27%.The removal rate of total nitrogen is equal to 81.12%.The nitrogen removal efficiency of the improved A/O process system far exceeds that of the traditional A/O process system.Decreasing the concentration of the carbon source in the influent water so that the C/N ratio is equal to 6:1,the nitrogen removal performance of the improved A/O process is analyzed.The results show that the nitrogen removal efficiency of the improved A/O process is significantly higher than that of the traditional A/O process.O process.The average concentration of total nitrogen in the effluent of the improved A/O process system is equal to 20.43mg/L,and the average removal rate of total nitrogen in the system is equal to 51.46%.The average concentration of total nitrogen in the effluent of the traditional A/O process system is equal to 22.6mg/L.The average removal rate of total nitrogen is equal to 45.58%.Under the condition of low carbon source,the improved A/O process system and the traditional A/O process system have the same total nitrogen removal efficiency,but the improved A/O process system has a higher total nitrogen removal rate.