A^2/O工艺中二沉池污泥上浮的原因与对策

Causes and Countermeasures on Sludge Floating in Secondary Sedimentation Tank in A^2/O Process

针对A2/O工艺处理城市污水时出现的二沉池污泥上浮现象,探讨分析了其主要原因及对策。分析结果表明,丝状菌过度繁殖引起的污泥膨胀和二沉池底部污泥发生的反硝化作用是二沉池污泥上浮的主要原因。其中,丝状菌性污泥膨胀主要是由水温太低引起的,而进入二沉池的硝态氮浓度过高导致了底部污泥的反硝化作用。在好氧池的DO>2mg/L、pH处于适宜范围内的条件下,通过强化缺氧池的反硝化作用、调整污泥回流比、减少污泥在二沉池中的停留时间等措施,有效抑制了二沉池中污泥的上浮。

For sludge floating phenomenon in the secondary sedimentation tank in which A2/O process is used to treat municipal sewage, the causes and countermeasures were analyzed. The results show that the sludge floating is mainly due to the sludge bulking caused by excessive growth of filamentous bacteria and the sludge denitrification occurred at the tank bottom. The filamentous sludge bulking is mainly caused by too low temperature, and the denitrification of sludge at the bottom is caused by excessive nitrate nitrogen entering into secondary sedimentation tank. When DO is more than 2 mg/L and pH is in an appropriate range in aerobic tank, the sludge floating in the secondary sedimentation tank can be effectively inhibited by enhancing the denitrification in anoxic tank, regulating the sludge return ratio, reducing the sludge retention time and so on.