| 摘要 |
PROBLEM TO BE SOLVED: To provide efficient sand collecting equipment which has high cost performance. SOLUTION: A pond bottom 21 of a rainwater storage reservoir (a reservoir pond) 1A forms a sand collecting channel having a downward gradient toward a trough 41 (a sand collecting pit). A part of sewage flowing in the rainwater storage reservoir 1A is stored and held in a storing tank 32 of an adjacent temporary storing tank 3 when the sewage flows in. When water level of the rainwater storage reservoir lowers, the stored water is discharged from an upper part of the gradient in the sand collecting channel and sand deposited on the pond bottom 21 of the rainwater storage reservoir is collected to a water discharging pit 4 by a discharging flow of the stored water toward the trough 41. Pulsation is produced in the discharging flow by repeating discharging / stopping of the stored water and the sand is carried away by the pulsation. The storing tank 32 is a sealed type and drawing of the sewage into the storing tank and holding and release of the sewage is performed by supplying/discharging air into/from an upper closed space in the tank. In order to wind up sunk sand, a turbulence forming unit 6A is disposed at the sand collecting channel. COPYRIGHT: (C)2005,JPO&NCIPI
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