| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for removing sand which is schemed such that a sand pump is not embedded by earth and sand collected into a sand collecting pit at the beginning or the like when starting sand removal operation.SOLUTION: In a method for removing sand of a settling basin, bottom surfaces in a region made by dividing a bottom surface of a settling basin into a plurality of parts are turned to a drained state, low-pressure water is injected to each region in a prescribed order, earth and sand deposited on the bottom surface of the region is caused to flow to a sand collecting pit through a main trough and, at the same time, the earth and sand caused to flow to the sand collecting pit is conveyed to an external part of the settling basin by a sand pump. Therein, there are provided a region nozzle for injecting low-pressure water to the bottom surface of the region and a trough nozzle for causing the earth and sand deposited on the main trough and a sand collecting pit inclination surface to flow out toward the sand collecting pit and injection of each region nozzle and injection of the trough nozzle are alternately performed. |
