| 摘要 |
<p>PURPOSE:To discharge scum by allowing the same to flow in a fixed type scum removing apparatus by pushing up the water level of an opening and closing part by utilizing the air pressure in a hermetically closed part at a final stage of aeration by providing an open part and the hermetically closed part to a reaction tank. CONSTITUTION:An aeration process is started by sending air to an air diffusion pipe 10. When an air vent pipe is closed by operating an opening and closing valve 17 at a definite time before the completion of the aeration process, the air from the air diffusion pipe 10 is accumulated in the upper part of a hermetically closed part 5 and the water level in the hermetically closed part gradually falls by the air pressure and the position of the water in an open part 4 rises with the falling of said water level and the scum floating on the surface of the water overflows a flooding layer 14 to flow in a scum removing apparatus 13 and is taken out of a tank from a withdrawing pipe 15. After a definite time, the air vent pipe 16 is opened and the sending of the air from the air diffusion pipe 10 is stopped to complete the scum removing process and the aeration process to enter a sedimentation process. ln this case, since water is also discharged to a certain degree along with the scum in the previous process, the water level slightly falls from the original water level (a).</p> |
