| 摘要 |
<p>PURPOSE:To remarkably reduce the amt. of excess sludge generated by separating the sludge to be solubilized into two parts, hydrolyzing each part with an acid or alkali, combining both parts and supplying the mixture to a nitrifying and denitrifying tank. CONSTITUTION:The skimmed night soil 1 is introduced into the biological nitrifying and denitrifying tank 2, nitrified and denitrified. The effluent activated sludge slurry 3 is filtered by an ultrafilter 4 (UF) to collect and remove SS, and separated into clear biologically treated water 5 and a slurry 6 free of SS. A part 7 of the slurry 6 is returned to keep the activated sludge concn. in the tank 2 at a specified value. The other part 8 is separated into two parts, and one part is supplied to a sludge solubilizing tank 9 by an acid and a sludge solubilizing tank 10 by an alkali. The org. matter in the sludge is hydrolyzed in the sludge solubilizing tanks 9 and 10.</p> |
