Production Test Of BBSNP Process For Removing Nitrogen And Phosphorus Pollutants From Municipal Wastewater

The traditional A/O,A~2/O,SBR and oxidation ditch processes are the most used processes in the existing urban sewage treatment plants in China,but in the actual operation of urban sewage treatment plants,The AAO process exposes many problems such as high drug consumption,high energy consumption,and high sludge production.BBSNP(Bio-Bi-Selector Nitrogen and Phosphorus removal process)is an improved A~2O process(see Figure 1-2),which changes the sludge reflux compared to the traditional A~2O process.The point position increases the reflux of the mixture,which can effectively reduce the effect of nitrate nitrogen on anaerobic phosphorus release,and form an anaerobic-anoxic cycle,which strengthens the growth and enrichment of denitrifying phosphorus-accumulating bacteria in the system.In the absence of oxygen and phosphorus,the denitrification is completed at the same time,achieving“one carbon and dual use”,which greatly saves the demand for external carbon source,aeration and sludge production.This experiment carried out a productive test study based on the pilot test.The effects of mixture reflux ratio,sludge residence time and sludge concentration,low temperature on the denitrification and dephosphorization of BBSNP process were studied.The nitrogen and phosphorus removal capacity of BBSNP treatment for low carbon and nitrogen ratio domestic sewage was studied.The treatment effect of BBSNP process and A~2/O process on low carbon-nitrogen ratio domestic sewage;comparing the difference of sludge yield and aeration between BBSNP process and A~2/O process;analyzing BBSNP under low carbon to nitrogen ratio influent condition Factors affecting the total nitrogen removal rate of the process.This experiment believes that SRT(sludge residence time)will have a great impact on the nitrogen and phosphorus removal efficiency of the system.This study believes that the BBSNP process sludge age should be controlled at 15d.When the influent COD concentration is low,the overall sludge concentration of the system will be lower,and the sludge concentration of the anaerobic tank will be lower.At this time,the reflux ratio of the system mixture should be controlled at 200%,and the ammonia nitrogen removal effect of the BBSNP process at low temperature will be It is worse,but it can still meet the national first-class A standard,and the total nitrogen removal effect will also be worse,but it can still reach the national four categories of water standards.Comparing the A~2O process in the low temperature period under the same conditions,the removal effect of total nitrogen and ammonia nitrogen in the BBSNP process can be seen that the BBSNP process has a large denitrification advantage in the low temperature period.The BBSNP process is superior to the A~2O process in the treatment of low carbon nitrogen to domestic sewage.And compared with the A~2O process,the BBSNP process gas is relatively low,saving 21.60%of the aeration and reducing the sludge production by 44.74%.In this paper,the factors affecting the total nitrogen removal rate of the system under low water-nitrogen ratio influent conditions are analyzed.It is found that the higher anoxic phosphorus uptake rate is more conducive to the removal of total nitrogen.The increase of the reflux ratio of the mixed solution will also increase the total nitrogen removal rate,but the nitrate-nitrogen accumulation occurs in the anoxic tank when the reflux ratio of the mixture is 300%,so the reflux ratio of the nitrifying solution should be controlled at 300%.Residual alkalinity is another important factor affecting the removal efficiency of total nitrogen in the system.When the residual alkalinity of the system is insufficient,the pH of the reactor drops significantly and the total nitrogen removal effect deteriorates.Therefore,the BBSNP process is used to treat high total nitrogen and high ammonia nitrogen wastewater.A basicity check is required to ensure a certain residual alkalinity.