| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress the generation of surplus sludge even with a smaller device by increasing the degree of degradation. SOLUTION: A part of sludge is withdrawn from lines 6 and 7 for returning the sludge from a settling tank 4 to an activated sludge tank 1. The withdrawn sludge is introduced into a chemical treating tank 9 and chemically treated with sodium hydroxide. The chemically treated sludge is crushed by an ultrasonic crusher 12. After that, the sludge is returned to the activated sludge tank 1 through a line 13.</p> |
