焦化废水工业处理装置和实验室装置硝化菌群的分子比较

Comparison of nitrifying populations between a lab-scale system and an industrial system treating coking wastewater

摘要:

反应器的群落结构分析有助于对工业装置的故障原因进行诊断。为了解决某焦化废水处理装置硝化功能低下的故障,构建了一套相似的实验室装置作为参照系统,该装置的硝化功能良好。通过工业装置和实验室装置好氧池生物膜16SrDNA克隆文库的比较,分析了它们之间硝化菌群的组成差异。实验室装置克隆文库的构成说明Nitrosomonas europaea-Nitrosoccus mobilis类群和Nitrospira属Ⅰ亚区系分别是该工艺条件下优势的氨氧化菌和亚硝酸氧化菌,但工业装置的克隆文库中却没有找到任何与硝化菌序列相近的克隆,这说明工业装置中硝化菌的多度较低。进一步使用Taqman荧光探针实时定量PCR测定了样品中Nitrospira属的多度,实验室装置中Nitrospira属16S rDNA的拷贝数达到3.4×10⁶个/微克基因组DNA,而工业装置的测定值不到实验室装置的1/300。这些试验结果都表明工业装置好氧池微生物群落中缺少适当的硝化菌群是造成其硝化能力低下的重要原因。提高菌群中Nitrosomonas属和Nitrospira属的多度是解决工业装置硝化能力低下的关键。

Abstract:

Molecular analysis of community structure can help diagnose problems in malfunctioning full-scale wastewater treatment system. A lab-scale A₁-A₂-O fixed biofilm system with highly efficient nitrification (NH₃-N removal at 95.2%) was set up as a reference for an industrial system with poor performance of nitrification (NH₃-N removal efficiency at -106%) for treating coking wastewater. Composition of nitrifying bacteria of biofilm samples in aerobic reactors of the two systems was compared by 16S rDNA clone library analysis. The composition of clone library of the lab-scale system indicate Nitrosomonas europaea-Nitrosoccus mobilis cluster and sublineage Ⅰ of Nitrospira genus are dominant ammonia and nitrite oxidizers in this process respectively. However, there were no clones related to nitrifying bacteria in clone library of the industrial system which suggested low abundance of nitrifying bacteria in this system. Further, Real-Time PCR with Taqman probe revealed that 16S rDNA copy number of Nitrospira in aerobic reactor of the lab-scale system was 3.4×10^{6/μg DNA of biofilm which is 300 times higher than that in the industrial system. The absence of Nitrosomonas and Nitrospira in the industrial system leads to poor performance of nitrification. Building up of a high population level of Nitrosomonas and Nitrospira in aerobic reactor is the key to improve efficiency of nitrification of the industrial system.}