一体化A/O生物膜反应器脱氮特性研究

Study on nitrogen removal performance of an integrated A/O biofilm reactor

采用新型的一体化A/O生物膜反应器,对生活污水进行脱氮处理实验。研究了溶解氧（DO）质量浓度对硝化和反硝化作用的影响,并对反应器的脱氮特性和降解机理进行了探讨。结果表明：DO对一体化A/O反应器脱氮影响较大,随着好氧区DO的增加,NH3-N和TN的去除率相应增加。当DO为2~4 mg/L时,发生同步硝化反硝化作用,NH3-N和TN去除率相当。当DO为5~6 mg/L时,NH3-N和TN的平均去除率分别达到97.0%和68.6%,出水NH3-N浓度小于2 mg/L,TN浓度小于15 mg/L。但DO过高会造成NO3--N和NO2--N的积累。一体化A/O反应器流态趋于全混式,硝化作用主要在好氧区进行,而反硝化脱氮作用主要在缺氧区进行,反应器内pH值保持稳定。采用的悬浮球生物填料能形成好氧和缺氧微环境,从而使反应器产生好氧反硝化现象。

A novel integrated biofilm A/O reactor was used to treat domestic sewage.The effect of dissolved oxygen（DO） mass concentration on nitrification and denitrification was investigated,and the nitrogen removal performance and mechanism of the reactor were discussed.The experimental results show that the DO is a major factor affecting nitrogen removal from the sewage in the integrated biofilm A/O reactor,and the reactor can simultaneously carry out nitrification and denitrification in one unit.The removal efficiency of NH3-N and TN increases with the increasing of DO mass concentration in oxic zone of the reactor.When DO mass concentration of oxic zone is about 2~4 mg/L,the reactor can perform simultaneous nitrification and denitrification,so the removal efficiency of NH3-N and TN is equal almostly.When DO mass concentration is about 5~6 mg/L,the average removal efficiency of NH3-N and TN reaches 97.0% and 68.6%,respectively,the effluent mass concentration of NH3-N is less than 2 mg/L,and TN is less than 15 mg/L.But the mass concentration of NO-3-N and NO-2-N in the reactor would be accumulated at high DO mass concentration.The integrated biofilm A/O reactor is nearly mixed completely by aeration,the nitrification is carried out in oxic zone,and the denitrification is carried out in anoxic zone,the pH value would be kept stable in the reactor.The biofilm media of suspended ball can form oxic/anoxic microenvironment,so denitrification can perform under aerobic condition.