| 摘要 |
PROBLEM TO BE SOLVED: To provide a cleaning method of a water treatment device formed by filling an effectively cleanable particle, even when including SS, a foreign substance, a microorganism slime and a scale large in a sedimentation speed.SOLUTION: In the cleaning method of a downflow type water treatment device, a bottom part of the device 1 is provided with a catchment part 4 connected with a wash water supply line 5, a cleaning air supply line 6 and a drain line 7, and particle layers 3 and 2 are provided on the catchment part, and a drain line 8 is provided by separating a distance L from a stationary interface of the particle layer 2, and a raw water supply line 9 is provided in a device upper part. Cleaning is executed in order of water draining from a drain line 7, a flashing from a surface washing-wash water supply line, water washing from a surface washing and wash water supply line and water washing from the wash water supply line 5, and a flashing speed is larger than a succeeding water washing speed, and the following expression : V<L/T(in the expression, Vis the flashing speed (m/min), L is a distance (m) up to the drain line from the stationary interface of the particle layer, and Tsatisfies flashing time (min)). |
