常规和倒置A2/O工艺活性污泥微生物群落结构的比较

摘要

To explore the reason why removal efficiency of nitrogen and phosphorus in reversed anoxic-anaerobic-oxic (A2/O) process is higher than that in conventional A2/O process, bacterial community compositions of activated sludges from the two procedures were investigated by PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) technique and cultivation method. Betaproteobacteria and Gammaproteobacteria were detected as dominant bacteria in activated sludge from both processes. In the activated sludge of the reversed A2/O process, a large amount ofNitrosospirasp.,Rhodocyclus sp., and four uncultured bacteroidetes bacterium were detected by PCR-DGGE technique, while less of these bacteria were found in the conventional A2/O process.Shewanella algaesp.,Klebsiellasp., andRhodobacter sphaeroidesof Gammaproteobacteria were separated from the activated sludge of reversed A2/O process by cultivation method, while they were absent from the conventional A2/O process. The diversity of these above-mentioned bacteria species could account for the higher removal efficiency of nitrogen and phosphorus in the reversed A2/O process. Additionally, scanning electron microscopy showed that the activated sludge of reversed A2/O process was relatively loose, with lessFilamentous bacteria and noNostoc.%为了探究倒置A2/O工艺脱氮除磷效果优于常规A2/O工艺的机理,利用聚合酶链式反应-变形梯度凝胶电泳(PCR-DGGE)技术与纯培养方法分析了2种工艺活性污泥中微生物群落结构.结果显示,2种工艺活性污泥的优势菌群均含有β-变形菌与γ-变形菌;倒置A2/O工艺活性污泥中检测到大量的亚硝化螺旋菌、红环菌和4种未培养的拟杆菌,而这些菌类在常规A2/O工艺中含量较少;利用纯培养方法在倒置A2/O工艺活性污泥检测到的γ-变形菌纲希瓦氏菌属、克雷伯氏菌属和类球红细菌在常规A2/O工艺样品中未检测到.推测以上菌种的存在可能是倒置A2/O工艺具有较高脱氮除磷效果的主要原因.此外,扫描电镜结果显示倒置A2/O工艺活性污泥较为疏松,丝状细菌含量较少,且不存在念珠状细菌.