| 摘要 |
PURPOSE:To certainly perform solid-liquid separation in an energy conserving manner, by a method wherein foamable org. waste water, to which biological treatment is applied, is subjected to aeration treatment and foams are returned to a biological treatment process while the effluent liquid after aeration and foaming treatment is subjected to solid-liquid separation treatment. CONSTITUTION:Residue removed excretion 1 is introduced into a nitration tank 3 without receiving the addition of diluting water and, when aeration treatment is applied to said excretion in this tank 3, it is foamed but defoamed by a defoamed by a defoamer 7. Effluent water 8 undergoing a biological treatment process, from which BOD and a nitrogen component are sufficiently removed, is flowed into an aeration foaming tank 9 opened to the atmosphere to receive aeration. Foams are violently generated in the aeration foaming tank 9 by a diffusing apparatus 6' and activated sludge flocs are adhered to the generated foams to be concentrated and separated in a foaming layer 10. When the effluent liquid 12 from the aeration foaming tank 9 is introduced into a precipitation basin 13, the precipitation speed of activated sludge is made high because a SS-concn. is reduced and said sludge is easily precipitated. The precipitated sludge 14 is dehydrated in a sludge treating process.
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