| 摘要 |
<p>PURPOSE:To easily change aerobic and anaerobic operations by a method wherein the rotary shaft of the stirring blades of one tank is made movable in an up-and-down direction and moved upwardly at the time of anaerobic operation and a lower stirring blade is positioned in a liquid phase part and an upper stirring blade is positioned in a gaseous phase part. CONSTITUTION:When an aeration tank is set to in order to remove P, a handle is rotated to an anerobic state move the rotary shaft 6c of a first tank 1a and a lower stirring blade 6a is positioned in a liquid phase part 2 and an upper stirring blade 6b is positioned in a gaseous phase part 3 and the introduction of oxygen 5 is changed to a second tank 1b. The gaseous phase parts 3 of the tanks 1a, 1b communicate with each other through a communication hole 3a but, since oxygen flows downstream from the tank 1b and the upper stirring blade 6b is rotated in the gaseous phase part 3 and a gas-liquid boundary is not stirred, the tank 1a is held to an anaerobic state. In the case of N-removing operation, the rotary shaft 6c of the tank 1a is moved upwardly and oxygen 5 is introduced into the tank 1b and, further, a part of the liquid of a final tank 1d is circulated to the tank 1a as a circulating digested solution 9. In this case, the gaseous phase parts 3 of the tanks 1a, 1b also communicate with each other through the communication hole 3a but, since oxygen 5 flows to tanks 1c, 1d, the tank la can be held to an anaerobic state.</p> |
