| 摘要 |
PROBLEM TO BE SOLVED: To provide 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 25, through which a filter material 23 can move; a filter material inlet port 32; a filter material discharge port; and air supply means for supplying air to the pumping passage 25. A hood 30 is disposed above the outer circumference side of the filter material inlet port 32, and the minimum distance Smin between the lower end of the hood 30 and a tank bottom and the maximum distance Tmax between the filter material inlet port 32 and the tank bottom have relation of Smin/Tmax<1. |
