FISH法对垃圾渗滤液硝化生物膜发育的观察与分析

Fluorescence in Situ Hybridization Analysis of Nitrifying Biofilms in Landfill Leachate Aerated Treating System

摘要:

氨氧化细菌的培养和快速检测一直是高浓度氨氮废水处理工程的调试和运行监测中的难点问题。利用荧光原位杂交（FISH）方法，对广州大田山垃圾填埋场渗滤液好氧处理过程中复合生物膜反应器不同挂膜时间的填料和相应时期的悬浮污泥中氨氧化菌的群落结构和动态变化进行了监测，并且用扫描电子显微镜（SEM）观察了相应时间段的生物膜的表面情况。结果表明，在挂膜初期，细菌首先在填料表面的凹陷处定居，随着挂膜时间的延长，填料上的细菌总数在增加。挂膜7d的填料上，氨氧化菌占全菌的比例为60％左右，挂膜20d的填料上，氨氧化菌占全菌的比例为40％左右；挂膜50d的填料上，已经形成了完整的生物膜菌群结构，其中氨氧化菌是最主要的优势菌群，它占全菌的比例保持在35％左右，这个比例在106d和155d的生物膜上仍然保持稳定。与填料同时取样的悬浮污泥，其氨氧化菌占全菌的比例远远低于同时期的填料上的比例，并且较不稳定。当出水氨氮浓度由30mg/L升高到70mg/L左右时，悬浮污泥中氨氧化菌的比例有所降低，而完整生物膜上氨氧化菌的比例仍然保持在30％左右并且对氨氮的去除起了主要的作用。

Abstract:

The cultivation and rapid detection of ammonia-oxidizers have been nodus in debugging and monitoring of high ammonia concentration wastewater treatment engineering.In this research，landfill leachate biofilms and suspended active sludge in different operation periods were sampled in Guangzhou Datianshan landfill leachate treating system.The in situ spacial organization of ammonia-oxidizing β-proteobacteria of samples was investigated by using fluorescence in situ hybridization (FISH) and with scan electron microscope (SEM).FISH and SEM observation revealed that in the start up period，micro-organisms initially attached on the lacunose part of carrier matrix.The bacteria total quantity kept growing in the biofilms of 7，20，50，106，155 day.The proportion of ammonia-oxidizing β-roteobacteria is approximately 60％ among all biomass in the early 7th day and 40％ in the 20th day samples，which means that ammonia-oxidizers firstly inhabit on the surface of the carrier matrix as the dominant component of the community in the process of biofilm forming.The biofilm was mature in the 50 day samples detected by FISH and SEM.The proportion of ammonia-oxidizer attached on the surface of carrier kept a relatively steady value of approximately 35% among all biomass in the 50th day，106th day and 155th day biofilms samples.The proportion of ammonia-oxidizers in the suspended active sludge sampling at the same time with biofilm samples is unstable and far below the proportion in biofilm grown on the carrier surface.The proportion of ammonia-oxidizers in suspended active sludge declined obviously when the concentration of NH4-N in the effluents increased to 70mg/L，but the proportion of ammonia-oxidizers in biofilms was not affected and kept a relatively steady value of approximately 30%，meanwhile，the ammonia-oxidizers still work well in the treating system.These results indicate that the application of FISH provide a rapid method for detection of nitrifying bacteria and an academic reference for debugging of environmental engineering.