MOLECULAR APPROACH TO THE MICROBIAL POPULATION IN ACTIVATED SLUDGE IN RELATION WITH THE PERFORMANCE OF WASTEWATER TREATMENT PLANTS

废水处理的目标过去是去除BOD，但现在要求去除氮和磷。随着要求的处理水平越来越高，我们需要了解微生物种群，并充分利用微生物的力量来去除污染物。在本研究中，我们使用了能够分析微生物种群结构的荧光DNA探针来分析污水处理厂活性污泥中的微生物种群。使用荧光DNA探针的一个重要问题是，无需培养就可以估计微生物种群。在本研究中，我们分析了北海道、东京、崎玉和冲绳地区15个污水处理厂的20条处理线的活性污泥。对每个处理厂进行了四次调查：1997年11月、1998年1月、1998年1月和8月。针对(L)真细菌，(2)变形杆菌α-亚类，(3)变形杆菌β-亚类，(4)变形杆菌伽马亚类，(5)革兰氏阳性GC高组分，(6)细胞吞噬-黄杆菌亚类的6个探针进行了研究，结果表明，在许多污水处理厂中，变形杆菌(α-+β-+γ-亚类)是真细菌的优势类群，其中α-亚类和β-亚类是最占优势的。微生物种群结构与污水处理厂的位置、水温、营养物质去除等条件之间没有显著的关系。但研究发现，规模较小的污水处理厂含有更多的真细菌，而本研究中使用的组特异性探针没有检测到这些细菌。在许多污水处理厂，从冬季到夏季，α-亚类增加，革兰氏阳性GC高组减少。

The goal of the wastewater treatment used to be the removal of BOD, but nowadays, the removal of nitrogen and phosphorus is required. As the required level of treatment gets higher, we need to understand he microbial population and to make the best of microbial power to remove pollutants. In this research, we employed the fluorescence DNA probes which enables the analysis of microbial population structure for the analysis of microbial population in activated sludge in wastewater treatment plants. One of the important points about using the fluorescent DNA probes is that microbial population can be estimated without cultivation.In this research, we analyzed the activated sludge in 20 treatment lines in 15 wastewater treatment plants in Hokkaido, Tokyo, Saitama, and Okinawa areas. Four surveys were conducted on each of the treatment plants ; November 1997, January, Nay, and August 1998. Six probes were used for the investigation which are targeted at (l)eubacteria, (2) Proteobacteria alpha-subclass, (3) Proteobacteria beta-subclass, (4) Proteobacteria gamma-subclass, (5) Gram positive GC high group, and (6) Cytophaga-Flavobacterium group.It was demonstrated that in many of the wastewater plants, Proteobacteria (alpha- + beta- + gamma-subclasses) were the predominant group of eubacteria, and that alpha-subclass and the beta-subclass are the most predominant in the Proteobacteria. No significant relationships were found between the microbial population structure and the conditions of the wastewater treatment plants, such as location, water temperature, and the nutrient removal. But it was found that the smaller wastewater treatment plants contain more eubacteria which were not detected by the group-specific probes used in this study. In many of the wastewater treatment plants, increase in the alpha-subclass and the decrease in the Gram positive GC high group from winter to summer were observed.