| 摘要 |
<p>PURPOSE:To enhance oxygen absorbing efficiency, by aerating a liquid to be biologically treated by oxygen-containing gas in the coexistence of aerobic bacteria in a froth generation part to form froth and providing drafts not only in the froth layer but also above an air diffusion device. CONSTITUTION:Excretion 11 is allowed to flow in a biological treatment tank without adding diluting water and violently aerated by air 14 in the coexistence of activated sludge in a froth generation part 13. A front layer 15 having bacteria adhered thereto is formed to the upper part of the front generation part 13 and a draft tube 16 is provided above an air diffusion device 14' in the front layer 15, whereupon, the froth rapidly rises through the draft tube 16 by a kind of airlift action and flows through a space 17 as down-flow and BOD digesting bacteria and nitrifying bacteria, wherein BOD and NH3-N in excretion are adhered to froth, are removed by oxygen.</p> |
