| 摘要 |
PROBLEM TO BE SOLVED: To provide a floating filter medium washing method for washing a clogged floating filter medium efficiently in a short time without making the size of a filtration tank larger and laying a screen under the floating filter medium. SOLUTION: Rising flow filtration is carried out by forming a packed layer 2 of the floating filter medium having 0.1-0.4 specific gravity in the filtration tank 1. When the layer 2 is clogged, washing water is introduced into the tank 1 from the upper part at >=1 m/minute flow velocity and discharged from the lower part. As a result, the layer 2 is moved and expanded downward, impurities and suspended solids are removed while the floating filter media moved downward together with the layer 2 are made to float rapidly in a sparse washing layer 9 and the whole of the layer 2 is washed while the layer 9 is moved downward.
|
