TREATMENT OR ORGANIC SEWAGE

摘要

PURPOSE:To eliminate the need for a stage for adsorptive removal of phosphorus after a membrane sepn. stage by bringing the microorganism slurry flowing out of a biological treatment stage for org. sewage into contact with a granular calcium phosphate compd. in the co-presence of calcium ions, then subjecting the same to a membrane sepn. CONSTITUTION:Night soil 1 subjected to scum removal is treated in the biological treatment stage. A material 4 such as Ca(OH)2 which dissociates Ca<2+> in water is added to the activated sludge 3 flowing out of the stage 2 and the sludge in introduced into a crystallization dephosphorization reaction vessel 5 where the particles of the calcium phosphate compd. such as phosphorus ore form a fluidized bed 6. PO4<3-> in the activated sludge slurry 3 is insolubilized by the crystallization dephosphorization reaction. Part of the slurry 7 flowing out in the upper part at the boundary face of the fluidized layer 6 is supplied to the membrane sepn. stage 8 consisting of an ultrafilter member, etc., where fine suspended solids such as activated sludge flocs and calcium phosphate in the slurry 4 are separated by the membrane and clean membrane-permeated water 9 is obtd.