| 摘要 |
<p>PROBLEM TO BE SOLVED: To make sludge, which ascends in a treatment tank in the company with an ascending flow from a biological sludge bed and accumulates on a treatment water discharge path, return surely to the biological sludge bed. SOLUTION: An upper part of a treatment tank 12 is partitioned into a treatment water discharge passage 16 and a gas collection part 20 having a space 18 for storing gas by dividing in a vertical direction, and the treatment water discharge passage 16 is connected underwater with a bottom end of the gas collection part 20 for communication with each other, and when sludge is accumulated on the treatment water discharge passage 16, water level in the treatment water discharge passage 16 is lowered by a water level regulator 24 using gas pressure generated in the treatment tank 12. The sludge is made to fall onto a biological sludge bed from a bottom end of the treatment water discharge passage 16 by a water level descending force at the time of lowering the water level.</p> |
