不同DO下MBR内微生物群落结构与运行效果关系

Relationships between microbial community structure and the performance of MBR under different dissolved oxygen

应用A/O-MBR处理实际生活污水,考察了不同溶解氧(DO)条件下,微生物群落结构与其处理效果的对应关系.结果表明,DO浓度在0.2～4.0mg/L对COD去除效果无明显影响,COD平均去除率均在90%以上.DO浓度变化对NH4+-N去除影响较大,DO浓度下降到0.2mg/L时,NH4+-N平均去除率由99%下降到65%.通过PCR-DGGE分析,较高DO条件下(4.0,2.0mg/L)的总细菌微生物群落多样性高于较低DO条件(0.5,0.2mg/L),但其群落结构变化与与反应器的处理效果对应关系不明显;氨氧化菌的群落结构变化较明显,且在不同的DO条件下起主要作用的氨氧化菌的菌属不同,其群落变化与反应器的NH4+-N去除效果相对应,DO为2.0,0.5mg/L时氨氧化菌群落结构比较相似,此时反应系统的脱氮效果也比较好.

Microbial community structure and nutrient removal performance under different dissolved oxygen were investigated using Anoxic-oxic submerged membrane bioreactor（A/O-MBR） for municipal wastewater treatment.Results showed that the COD removal was not influenced markedly by the variations in DO between 0.2mg/L and 4.0mg/L,and the COD removal was more than 90% during the whole experiment.However,the ammonia nitrogen removal was more sensitive than COD,and the ammonia nitrogen removal dropped from 99% to 65% when DO decreased to 0.2mg/L.The PCR-DGGE analysis showed that the diversity of total bacterial community was abundant when A/O-MBR was run at high DO（4.0mg/L and 2.0mg/L）,and the relationships between the total bacterial community structure and the performance of MBR was not very obvious.On the contrary,the ammonia oxidizing bacterial community composition had a more obvious shift with the variation of DO concentration,and the species of ammonia oxidizing bacteria which play major role were different under different DO conditions,which were corresponded to the removal efficiency.The ammonia oxidizing bacterial community composition were similar under the DO concentration of 2.0mg/L and 0.5mg/L,and the nitrogen renmoval was enhanced.