| 摘要 |
PROBLEM TO BE SOLVED: To provide a water treatment device, a moving-bed type filter tank, and a clarification tank, for which the closure of a pumping passage due to the bridge formation of a filter material hardly occurs.SOLUTION: An air lift pump P comprises: a water channel wall 26 for forming a pumping passage, through which a filter material can move; a filter material inlet port 32 at the lower end of the pumping passage; a filter material outlet port at an upper portion of the pumping passage; and air supply means 27 for supplying air to the pumping passage. The lower end of the water channel wall 26 forming the outer circumference shape of the filter material inlet port 32 is shaped such that the distance from a bath bottom portion varies, and such that the longest distance Tmax and the shortest distance Tmin have relation of 0≤Tmin/Tmax<1.0. |
