A^2/O工艺强化反硝化除磷体系中微生物特性分析

Characteristics of Sludge Community in A^2/O Process with Denitrifying Phosphate Removal Performance

为了更直观地认识反硝化除磷体系中生物脱氮除磷机理及运行状态,本文尝试了对A2/O工艺强化反硝化除磷体系在稳定运行期的活性污泥采取直接染色的手段,观察聚-β羟基丁酸(PHB)和聚磷酸盐(Poly-P)的沿程变化状况,同时结合活性污泥的电镜扫描图像,考察该系统的微生物菌群特征.试验结果表明,在厌氧阶段,微生物细胞内PHB的量大幅提高,上清液中磷酸盐的含量上升,聚磷酸盐含量明显下降,粒径为1~1.5μm、呈球状和棒状的菌群构成的葡萄状细胞簇占居优势;在缺氧阶段,微生物细胞内PHB的量下降,上清液中磷酸盐含量下降,聚磷酸盐含量上升,粒径为0.5~1μm的椭球菌与1.0~1.5μm的球杆菌占优势;在好氧阶段,微生物细胞内PHB的量较低或接近零,上清液中磷酸盐的含量接近零,聚磷酸盐含量明显上升,此时粒径1.0~1.5μm的球菌以单个或成对出现,球菌不再饱满,呈现接近消失的状态.相比之下,单纯的脱氮系统则不存在上述微生物特性的变化.

In order to well understand the mechanism of nitrogen and phosphorus removal and operational state in denitrifying phosphorus removal system, this study aimed to analyze the characteristics of activated sludge in quasi-state A^2/O process by means of direct staining together with SEM analysis, and observe the variation of PHB and polyphosphate granule in the cells at different phases. The results showed that at the anaerobic phase, the PHB concentration in the cell and orthophosphate concentration of the anaerobic effluent obviously increased, the poly-P concentration in the cell decreased, and the cucci and bacilli with a size of 1.0 - 1.5 μm were dominant and formed grapy cellular cluster. At the anoxic phase, the PHB concentration and orthophosphate concentration decreased significantly, the amount of poly-P increased, and the elliptical cucci of 0. 5 - 1 μm and spheral bacilli of 1.0 - 1.5 μm were dominant. At the aerobic phase, the PHB and orthophosphate concentration almost reduced to zero, the poly-P increased significantly, cucci appeared single or in pair, and the contour of sphere was blur and almost disappeared. In contrast, only nitrogen removal system had no such changes. Fig 8, Ref 12