Study On The Properties Of Nitrogen And Phosphorus Removal Of A~2/O-MBNR Combined Process

Continuous flow A²/O-MBNR combination process (MBNR is the modified biofilm-nitrification reactor) is a kind of new improved biological treatment process based in the A²/O process. It is a two-sludge process that a biofilm section is added after A²/O process to make nitrifying bacteria and other bacteria grow separately and achieve phase separation cultivation.On the basis of the previous experimental results,select the best sludge age for 5 days,the reflux ratio for 200%, the flow rate for 1L / h,and sludge return ratio for 80%. Then investigate the impact on the combination process of influent COD,TN and TP volume load respectively.And the operational condition of the combination process was discussed under the lower C / N ratio (COD / TN :3-11) and C / P ratio (COD / TP :25-65). The results are as follows.Influent COD, TN and TP volume load had little effect on the removal of COD and NH4 +-N. by the combination process. Influent COD volume load had certain effect on the removal of TN and TP: With the increase of influent COD volume load,TN removal rate of the system ranged between 69% and 77%,when the average influent COD volume load was 0.873 kgCOD/(m³·d), TN removal rate reached the maximum; TP removal rate ranged between 65% and 71%,when the average influent COD volume load was 0.673 COD/(m³·d),TP removal rate reached the maximum. Influent TN volume load had some effect on the removal of TN and TP:With the increase of influent TN volume load,TN removal rate ranged bentween 65% and 74%,when the average influent TN volume load was 0.098kgTN/(m³·d),TN removal rate reached the maximum.;TP removal rate ranged between 70% and 79%,when the average influent TN volume load was 0.077 kgTN/(m³·d),TP removal rate reached the maximum.Influent TP volume load has little effect on TN removal and had some effect on the TP removal:TP removal rate ranged between 70% and 80%,when the average influent TP volume load was 0.0069 kgTP/(m³·d), TP removal rate reached the maximum.Influent C / N ratio and influent C / P ratio almost had little effect on the removal of COD and NH₄⁺-N. Influent C / N ratio had some effect on the nitrogen and phosphorus removal: When COD / TN ratio increased from 3 to 11,TN removal efficiency rose from 65% to 75%; When COD / TN ratio increased from 3 to 7,TP removal rate rose from 55% to 75%,and when the ratio increased from 7 to 11,TP removal rate fell to 70%. Influent C / P ratio had little effect on the nitrogen removal and had great effect on the phosphorus removal: When COD / TP ratio increased from 25 to 65,TN removal rate maintained at 71%,and TP removal efficiency rose from 40% to 80%,that phosphorus removal performance had greatly enhanced.