| 摘要 |
<p>PURPOSE:To markedly reduce the generation amount of excessive sludge by returning a part of sludge subjected to solid-liquid separation after aerobic biological treatment to a biological treatment tank while adding an alkali agent to the other part of the sludge and solubilizing the org. matter in the sludge before supplying said sludge to the biological treatment tank. CONSTITUTION:Inflow sewage 1 is aerated and supplied to a sedimentation tank 3 to perform the sedimentation of activated sludge. The greater part of the sludge 6 separated by sedimentation is recycled to an aeration tank 2 and MLSS in the aeration tank 2 is held to predetermined concn. The other part 8 of said sludge 6 is supplied to a sludge concn. process 9 and a part of conc. sludge 10 is supplied to a sludge solubulizing tank 11. An alkali agent 12 is added to said sludge to adjust the pH thereof to 10 or more and this sludge is stayed in the tank 11. The cell constitutional components of various bacteria constituting the activated sludge are hydrolyzed and solubilized in the solubilizing tank 11. The solubilized sludge 14 is supplied to the aeration tank 2 to be biologically decomposed into CO2 and H2O.</p> |
