TREATMENT OF ORGANIC SEWAGE

摘要

PURPOSE:To obtain highly purified treated water by subjecting a slurry of activated sludge to solid-liq. separation, adding a specified flocculant and activated carbon to the separated water and carrying out separation with a membrane. CONSTITUTION:Night soil 1 is allowed to flow in a biological nitrification and denitrification tank 2, where it is nitrified and denitrified. A slurry 3 of activated sludge flowing out of the tank 2 enters a sedimentation tank 4, where water is separated by sedimentation. A flocculant 10 such as FeCl3 or ferric polysulfate is added to the separated water 9 in a stirring vessel 11 and mixed under acidic conditions and this mixture is allowed to flow in a vessel 12 for contact with powdery activated carbon. A slurry contg. activated carbon is sent by a pump 14 from the vessel 12 to a separating apparatus 15 provided with an ultrafiltration membrane and clean water 16 passed through the membrane is discharged. Foaming is prevented and the quality of treated water is improved.