| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for treating concd. sewage by which a necessary amt. of oxygen is sufficiently supplied to the activated sludge without increasing the amt. of aeration air. SOLUTION: An org. sewage 5 having high contents of org. matter and nitrogen is biologically treated in a reaction tank 1 in which an immersion-type membrane separator 21 is set in this membrane-separation activated sludge process. In this case, the concd. sewage 5 is pretreated by a pretreating equipment 6 to remove the foreign matter by a screen, and the concd. sewage 5 is injected into an air supply system 2 for supplying aeration air to a diffuser pipe 23 in the separator 21. Oxygen is dissolved in the concd. sewage 5 at high speed in the air supply system 2, and the concd. sewage 5 in which oxygen is sufficiently dissolved is supplied into the tank from the diffuser pipe 23 along with the aeration air.</p> |
