膜-生物反应器与活性污泥工艺处理氨氮废水的微生物特性比较

考察了膜-生物反应器（MBR）与活性污泥工艺（CAS）处理无机氨氮废水的对比研究.结果表明,同CAS相比,MBR处于高容积负荷、低污泥负荷的运行状态下,硝化效果较好,除了短期的pH控制故障外,氨氮转化为硝酸盐氮的转化率可达99%.随着运行时间的增加,膜组件的截留作用导致MBR内胞外多聚物的积累,电镜扫描（SEM）不能观察到运行后期微生物的形态变化,然而,CAS中微生物形态变化不大.2个反应器中硝化菌、亚硝化菌和异养菌的变化趋势是一致的,异养菌仅为硝化细菌的万分之一;但与MBR相比, CAS中硝化菌数量少32%,亚硝化菌的数量少35%,异养菌数量少24%.

Comparison of Microbial Characteristics Between Membrane Bioreactor and Activated Sludge System on Treating Ammonia-Bearing Inorganic Wastewater

Comparative studies of microbial characteristics between a membrane bioreactor (MBR) and a conventional activated sludge system (CAS) have been conducted in treating ammonia-bearing synthetic inorganic wastewater under similar conditions. Compared to the CAS, the MBR was operated under the conditions of high volumetric loading and low sludge loading, except for a short period after the failure of pH control, the NO~-_3-N transformation rate in the MBR was constantly above 99%. Because of the interception of the membrane module, extracellular polymeric substances (EPS) were accumulated in the MBR with the prolongation of the operational period, and it was difficult to identify the microbial morphology clearly in the later period by scanning electron micrograph (SEM). However, SEM could distinctly identify the microbial aspects in the CAS in the whole operating period. The ammonia-oxidizing bacteria and nitrite-oxidizing bacteria were prominent bacteria in both the reactors, and only minor heterotrophic bacteria appeared in the reactors. Compared to the MBR, the average numbers of ammonia-oxidizing bacteria, nitrite-oxidizing bacteria and heterotrophic bacteria were 32%, 35% and 24% fewer in the CAS, respectively.