JP2008303558A5 - - Google Patents

Claims (5)

A method of collecting sand in sewers under constant water flow, which is provided in parallel with the direction of sewage flow and has multiple sand basins with sand collection pits on the bottom, and separate inflow of sewage into each sand basin. And a normally open entrance gate for substantially blocking, each sedimentation basin can be individually separated from other sedimentation basins after preventing the inflow of sewage, During low sewage volume, water flow to some of the sand basins is continued, while water flow to the remaining sand basins is blocked and separated from the water settling basins. By draining the blocked sand basin, the sand basin is substantially emptied. In the sand basin that is substantially emptied, the sediment deposited on the bottom surface is accumulated in the sand collection pit by the water flow along the bottom surface of the sand basin, and sanded together with the sewage. A sand collection method that uses a pump. The sand collection method according to claim 1 , wherein sand collection in a plurality of sand basins is sequentially performed in a specific time zone where the amount of water is low. A sand collecting device for carrying out the method according to claim 1, wherein the sand collecting device is provided in parallel with the flow direction of sewage, each forming a sand collecting pit on the bottom surface, Multiple sedimentation basins with collection means and means for discharging sewage and sedimentation from the sand collection pit, pump wells downstream of the sedimentation basins, drainage pumps located in the pump wells, and inflow of sewage into each sedimentation basin Inlet gates for controlling the opening and closing of the sand and the sand basins where the entrance gate is closed to prevent the inflow of sewage individually into each sand basin and separate it from other sand basins A sand collecting device comprising a separating means for separating the sand from other sand basins. In collecting sand according to claim 3, wherein the pump well is provided downstream of the plurality of sand basin to be shared by multiple sand basin, exit gate provided between said pump well with each grit chamber Is a sand collecting device constituting the separating means . 4. The sand collecting apparatus according to claim 3, wherein the pump well is independently provided downstream of each settling basin, and a weir for separating pump wells constitutes the separating means .