亚硝酸盐氧化菌(NOB)的富集培养与其污泥特性分析

Enrichment and sludge characteristics analysis of nitrite oxidizing bacteria(NOB)

为了解亚硝酸盐氧化菌(NOB)特性,以某中试SBR的剩余污泥为接种污泥,以NO2--N为底物,采用逐步提高进水NO2--N浓度的方式,通过控制高游离亚硝酸(FNA)浓度联合高DO浓度对NOB进行富集培养.65d后,荧光原位杂交(FISH)技术分析结果显示NOB占细菌总数的80%以上[Nitrobacter(NOB的一个种,菌体呈杆状或梨状):80%;Nitrospira(NOB的一个种,菌体呈螺旋状):5%],表明成功富集培养出NOB为优势菌种的活性污泥.并且自然形成颗粒污泥,MLSS约为700mg/L,MLVSS/MLSS为0.278,SVI约为6mL/g.富集后污泥SVI较低的原因可能是污泥无机化程度高,污泥以无机盐沉淀为晶核形成颗粒污泥.试验结果表明,该污泥能够处理NO2--N浓度为1000mg/L的污水,比硝化速率为131.03mg/(g MLVSS·h),比耗氧速率为169.5mg O2/(g MLVSS·h).

Nitrite oxidizing bacteria （NOB） was cultured mixedly in whether nitrification sludge or partial nitrification sludge system, as a result, its characteristics are not so clear to the researchers. In this paper, NOB, which was inoculated by the excess activated sludge from the pilot-scale SBR in the same lab, was enriched with the way of increasing NO2--N concentration gradually, and combining high concentration of Free nitrite acid （FNA） and DO. After 65days, FISH analysis showed that more than 80% of the bacteria population was NOB （Nitrobacter： 80%; Nitrospira： 5%）, which demonstrated the successful enrichment of NOB. Furthermore, the activated sludge granulated naturally under the average MLSS concentration, MLVSS/MLSS and SVI of 700mg/L, 0.278and 6mL/g, respectively. The reason about the extremely low SVI was probably that the sludge had high fraction of inorganics, which could be used as crystal nucleus to form the granules. Results of the research indicated that even with the wastewater whose NO2--N concentration was up to 1000mg/L, this sludge could play a good performance with specific nitrifying rate and specific OUR of 131.03mg/（g MLVSS·h） and 169.5mg O2/（g MLVSS·h）, respectively.