| 摘要 |
PURPOSE:To reduce the amt. of sludge produced and to carry out rational low-cost treatment by adding an alkali agent contg. Mg to org. sewage, biologically nitrifying and denitrifying the sewage and adding a flocculant contg. Fe<3+> or Al<3+>. CONSTITUTION:Org. sewage 1 such as raw sewage or drainage is mixed with an excess concd. slurry 2, an alkali agent 3 contg. Mg is added and a polymer flocculant 4 is further added. PO4<3-> and NH4<+> in the sewage 1 react with Mg<2+> to form flocks. These flocks are separated with a wedge wire screen 5 and the remaining liq. 9 is sent to a biological nitrifying and denitrifying stage 10, where nitrogen and BOD are removed. A flocculant 12 contg. Fe<3+> or Al<3+> is added to a slurry 11 of activated sludge discharged from the stage 10 to flocculate nonbiodegradable COD and colloidal particles. The resulting flocks are separated with a membrane 13. |
