| 摘要 |
PROBLEM TO BE SOLVED: To provide a settling basin structure with a simple spiral water passage where the diffusion of a flocculant is forcefully performed and separation to water which can be easily sluiced and soil particles is performed.SOLUTION: In a settling basin comprising a spiral water passage in a plan view,: the spiral water passage consists of an inclined water passage at a center part and a horizontal water passage at an outer periphery; the height of the water passage of an upstream side is higher than the height of the water passage of a downstream side in the inclined water passage; the height of the water passage of an upstream side is the approximately same as the height of the water passage of a downstream side in the horizontal water passage; and a water discharging passage is made at the outermost wall surface of the horizontal water passage. |
