| 摘要 |
<p>PURPOSE:To prevent the lowering of treating efficiency by a mechanism wherein, in the case of recovering activated sludge floated on a density separation layer by an endless belt type scraping apparatus, the starting end portion of the scraping apparatus in followed to floated activated sludge in accordance with the change of a liquid level. CONSTITUTION:The treating water is recirculated between a downward flow passage R2, an upward flow passage R3 and a connecting flow passage R1 and treated. On the other hand, the treating water is entered into a density separation tank 5 from an upward flow passage R3 through a flow passage R4 and floated activated sludge is recovered by an endless belt type scraping apparatus 11 and returned through a return flow passage R5. In this time, a drive apparatus 12 is operated by an automatic control apparatus 18 in such a way that the starting end portion of a scraping apparatus 11 is followed to floated activated sludge according to the change detection of a liquid level.</p> |
