OLAND生物脱氮系统运行及其硝化菌群的分子生物学检测

PERFORMANCE AND MOLECULAR MONITORING OF NITRIFYING BACTERIA IN NITRIFICATION STAGE OF OLAND SYSTEM

采用两阶段限氧自养硝化 -反硝化生物脱氮系统 (oxygen limitedautotrophicnitrificationanddenitrificationsystem ,以下简称OLAND)处理高氨氮、低COD的废水 .应用内浸式多聚醚砜中空膜 ,实现了污泥的完全截留 ,阻止了生物量的大量洗脱 ,并通过控制溶氧在 0 .1～ 0 .3mgL-1之间 ,实现了硝化阶段出水中氨氮与亚硝态氮浓度的比例达到最适值〔1 (1.2± 0 .2 )〕 ,从而为第二阶段的厌氧氨氧化提供理想的进水 ,进而获得较高的脱氮率 .同时应用荧光原位杂交技术对硝化阶段不同时期硝化菌群的变化进行分子生物学检测 ,揭示了随溶氧浓度的降低 ,氨氧化菌的数量基本保持恒定、亚硝酸氧化菌的数量略有减少的变化规律 ,并且发现 ,在两阶段限氧自养硝化 -反硝化生物脱氮系统中氨氮的氧化主要是由Nitrosomonassp .完成 ,亚硝酸的氧化主要由Nitrobactersp .完成 .图 4表 2参 2

A two-stage oxygen-limited autotrophic nitrification and denitrification (OLAND) system was applied for the treatment of sludge digester liquor with a high ammonium concentration and a low chemical oxygen demand (COD). A steady ratio of ammonium and nitrite 〔1(1.2±0.2)〕 from the effluent in the first stage (nitritation stage) was attained by controlling the dissolved oxygen in the range of 0.1～0.3 mg L -1, and the retention of biomass was achieved in the system with the immersed polyethersulfone membrane. Performance of nitritation stage was focused in this study, and a molecular technology-fluorescence In situ hybridization (FISH) was applied to analyze the shift of microbial community in this stage. It is showed that the amount of ammonium oxidizers was stable and nitrite oxidizers decreased a little bit with the drop of dissolved oxygen. At the same time, it was found that Nitrosomonas was the dominant bacteria of ammonium oxidizers which oxidize ammonium to nitrite, Nitrobacter is the dominant of nitrite oxidizers which oxidize nitrite to nitrate. Fig 4, Tab 2, Ref 22