新型一体化A^2/O-MBR的流速与溶解氧分布及脱氮除磷研究

THE DISTRIBUTION CHARACTERISTICS OF VELOCITY AND DISSOLVED OXYGEN IN A NOVEL INTEGRATED A^2/O-MBR PROCESS FOR NITROGEN AND PHOSPHORUS REMOVAL

新型一体化A^2/O-MBR反应器是通过在普通曝气池内加装气水混合流聚集器,将反应池分隔成不同反应区(厌氧/缺氧/好氧)而成。利用计算流体力学(CFD)技术,对2种构型的一体化A^2/O-MBR反应器内流体流速分布进行模拟。通过构建实验系统,实测系统内实际流体流速与不同污泥浓度下DO的分布特征,并考察脱氮除磷效果。结果表明:CFD模拟结果与实测反应器的流体流速分布基本一致;上升区与下降区宽度比为1∶5的反应器流速CFD模拟值较1∶2更优;加装气水混合流聚集器可使曝气能耗降低50%以上;通过变量曝气与控制上升区和下降区的污泥回流量,反应器上升区与下降区可分别形成好氧区与缺氧/厌氧区;系统脱氮除磷效率分别达到40%~60%和75%~90%,出水ρ(TN)、ρ(TP)分别低于12,0.2 mg/L。新型一体化A^2/O-MBR反应器具有能耗低、脱氮除磷能力强、构型设计新颖和实用性强等优点。

A novel integrated A^2/O-MBR innovated in this study was a reactor that was separated the different reaction zones（ anaerobic/anoxic/aerobic） by a buffer used for gas-liquid energy accumulation. Using the computational fluid dynamics（ CFD） technology,the distribution characteristics of flow velocity in the two configurations of integrated A^2/O-MBR process with the width ratios of the upflow and downflow zones of 1/5 and 1/2 were simulated. By estabilishing a integrated A^2/OMBR setup,the distribution characteristics of the flow velocity and dissolved oxygen（ DO） in system were measured,and the nitrogen and phosphorus removal capacities were investigated. The results showed that CFD simulation matched the experimental data very well. The flow field at a riser/downcomer width ratio of 1/5 was recongnised better than that of 1/2.The energy consumption could be reduced by up to 50% by adopting the gas-liquid energy accumulation. An obvious anaerobic/anoxic/oxic zones were formed by applying the intermittent aeration strategy and controlling the recirculation ratio between the riser and the downcomer. Under these conditions,the removal rates of total nitrogen,total phosphorus were 40% ~ 60% and 75% ~ 90%,the effluent TN、TP concentration were below of 12,0. 2 mg/L,respectively. This new configuration of integrated A^2/O-MBR has the advantages of low energy consumption,high nitrogen and phosphorus removalcapacities,novel configuration design,strong practicability,etc.