饮用水生物滤池的反冲洗机理研究

研究了反冲洗过程中的两种颗粒脱附力：水流剪切力和颗粒间摩擦力．并将它们同颗粒附着力进行了比较。结果表明，在滤层完全流化状态下，水流的剪切力还不到0．5N/m^2。与颗粒附着力相比。是微不足道的；但从反冲洗开始至滤层刚好流化时这段时间内，颗粒之间的摩擦力大小均在100N/m^2以上．这样大的摩擦力对颗粒脱附起到了大的作用。在反冲洗过程中，控制好滤层流态是一条控制微生物量的重要途径。

Study on the Mechanism of Backwashing in Biological filter for Drinking Water

Two forces during the backwashing, the sheer stress of water and the frictional stress between the particles of media, were studied and compared with the adhesion of biofihn. When filter media is completely fluidized, the sheer stress of water is less than 0.5N/m^2. Compared with the adhesion of particles, it is negligible. Before filter media is fluidized, the frictional stress between the media particles is almost more than 100N/m^2, and even more than 1000N/m^2. Thus, the frictional stress played a key role in the detachment of particles. During backwashing, the control of the fluidization is an important approach to control the biofilm.