This machine is suitable for mechanical sludge discharge in radial or vertical sedimentation tanks (with a diameter of less than 15m) without a central support pier. The machine is equipped with a fixed platform spanning the pool, and its overall load is applied to the center of the working bridge during operation. The sewage flows evenly around the pool through the central guide tube. As the flow rate decreases, the suspended matter in the sewage settles at the bottom of the pool. The bottom scraper collects the settled sludge in the central mud pit and discharges it from the sludge pipe by static water pressure.