Optimum Experimental Study On MSBR Process For Municipal Sewage Denitrification And Phosphorus Removal

This research project adopted a seven-cell MSBR process consisting of a sludge thickening tank,a pre-anoxic tank,an anaerobic tank,an anoxic tank,an aerobic tank,and two sequential batch tanks(SBR tanks).The influent water of this test device is mixed municipal sewage(domestic sewage and industrial wastewater).The influent COD is low,resulting in a low removal rate of nitrogen and phosphorus.During the actual operation of the test device,it was also found that the system sludge was easily lost during the drainage stage of the sequencing lot,resulting in a sludge concentration of less than 3000 mg/L,which reduced the removal rate of nitrogen and phosphorus from the MSBR process.Without considering the additional carbon source,how to improve the removal rate of nitrogen and phosphorus in this process has become the main issue in this study.This article studies from two aspects.First,considering the MSBR process water intake method and the addition of suspended fillers in aerobic tanks,the corresponding improvements are made.Then,on the basis of the improvement,the mixed liquor flow is studied to remove nitrogen from the process.Phosphorus effect.The operating conditions of this test are as follows: Design flow rate of inflow Q is1m3/h,flow rate of mixed liquid is 1.5Q,sludge return flow is 1.5Q.The above-mentioned operating conditions are unchanged,and the MSBR process is improved as follows: the water inlet mode is changed from a single pre-anoxic tank to a pre-anoxic tank and an anaerobic tank,and the inflow of the two tanks is respectively 0.2Q.,0.8Q;addition of suspended fillers in aerobic tanks.The improved MSBR process was compared with the removal effect of COD,ammonia nitrogen,total nitrogen and total phosphorus before the improvement.Based on the previous test,the mixed liquid return flow was set to 0,Q,and1.5 Q respectively.Other test conditions were unchanged.After normal operation for a period of time,the flow of the mixed solution was discussed.The process COD,ammonia nitrogen,total nitrogen,The effect of total phosphorus removal.The conclusions of this experiment are as follows:(1)In the conventional MSBR and improved MSBR comparison tests,it was found that the improved MSBR and conventional MSBR have basically the same COD removal efficiency,the average removal rate is stable at about 80%,and the average effluent concentration is about 20 mg/L.The improved MSBR process has a good effect on the removal of COD,and the effluent is stable.For the removal of ammonia nitrogen,theaverage removal rate of conventional MSBR was 90.51%,the average removal rate of modified MSBR was 96.94%,an increase of 6.43%,and the effluent concentration of ammonia nitrogen was within 1 mg/L.It can be concluded that the improved MSBR process further improves the ammonia nitrogen removal rate compared to the conventional MSBR process.In the removal of total nitrogen,the average removal rate of both processes is stable at about 48%,and the concentration of effluent is 14-15 mg/L,which meets the first-grade A standard.However,the removal effect of total nitrogen has not been significantly improved and still needs to be considered.Further increase the removal rate.For the removal of total phosphorus,the average removal rate of conventional MSBR is51.50%,the average removal rate of improved MSBR process is 71.30%,which is 19.80%higher than the conventional MSBR process,and the total phosphorus effluent concentration is stable within 1mg/L,so the improved MSBR The process does improve the efficiency of phosphorus removal.However,the average effluent concentration of total phosphorus failed to meet the Class A standard,and further consideration should be given to increasing the removal rate.(2)In the mixed flow reflow adjustment experiment,it was found that the reflux flow of the mixture had no effect on the COD removal of the process.COD removal efficiency is about 80% under three conditions,and the effluent concentration is also around 20mg/L,which can stably meet the Class A emission standard.The reflux flow of the mixed liquor also has no effect on the removal of ammonia nitrogen in the process.The ammonia nitrogen removal rate reached about 96% under three different conditions,and the effluent concentration also stabilized at about 0.7mg/L.The reflux flow of the mixed liquor has a great influence on the removal of total nitrogen in the process.When the flow rate of mixed liquid was 0,Q,1.5Q,the average removal rates were 44.01%,52.30%,and49.20%,respectively.From this,it can be seen that,in view of the denitrification effect,the mixed liquid flow rate Q is most suitable.The reflux flow of the mixed solution also has a great influence on the removal of total phosphorus in the process.When the flow rate of the mixed solution was 0,Q,1.5Q,the average removal rates were 77.06%,72.24%,and71.73%,respectively.From this point of view,it was found that the return flow rate of the mixed solution was 0 when considering the effect of phosphorus removal.Finally,in order to ensure the removal of nitrogen,the flow rate of the mixture was measured using Q.For the removal of phosphorus,later removal of iron or aluminum salt was considered.