溶解氧对一体式悬浮载体膨胀床生物脱氮的影响

Influence of Dissolved Oxygen on Biological Nitrogen Removal in Integrated Suspended Carriers Expanded Bed Reactor

以城市污水为处理对象,研究了一体式悬浮载体膨胀床(ISCEB)反应器中回流液的溶解氧浓度随时间的变化规律,同时考察了消除回流液中溶解氧的方法及其影响因素。结果表明,采用污水与回流液混合的方法可降低混合液中溶解氧的浓度,但其浓度>0.5 mg/L,不能满足反硝化脱氮的要求;向缺氧区中投加污泥可大幅降低溶解氧的含量,在污泥投量与混合液的体积比为1∶250、回流比为200%、回流液中溶解氧浓度为3.0 mg/L时,缺氧区中溶解氧浓度<0.5 mg/L,此时对氮的去除效果较好,对NH4+-N的去除率达94%,对TN的去除率达70%。

The variation of DO concentration in the integrated suspended carriers expanded bed （ISCEB） reactor for treating urban sewage was studied. The means of DO elimination and the influencing factors were investigated. The results show that mixing reflux liquid and urban sewage can lower the DO concentration. However, the concentration of DO is still above 0.5 mg/L, which cannot satisfy the requirements of denitrification. Adding sludge in the reactor can decrease DO content greatly. When the reflux ratio is 200% , the volume ratio of sludge to mixing liquid is 1 ： 250, and the dissolved oxygen in reflux liquid is 3.0 mg/L, the DO concentration becomes less than 0.5 mg/L and the removal rates of NH4^＋ -N and TN reach 94% and 70% respectively.