METHOD FOR REMOVING SUBSTANCE CAUSATIVE OF FLOW VELOCITY DECREASE IN MEMBRANE-SEPARATION ACTIVATED-SLUDGE PROCESS

摘要

A method is provided with which a substance causative of a decrease in flow velocity in filtration and present in a mixed liquor that contains activated sludge and is to be subjected to membrane separation is efficiently removed using a small amount of an organic polymeric coagulant. The method, which is for removing a substance causative of a decrease in flow velocity in filtration in a membrane-separation activated-sludge process, is characterized by: adding a remover for substances causative of a decrease in flow velocity in filtration, the remover containing, as an active ingredient, a water-soluble and/or water-absorbing cationic polymer having a structural unit represented by a given formula, to an activated-sludge-containing mixed liquor which is to be subjected to membrane separation and contains a substance causative of a decrease in flow velocity in filtration, the substance being at least one of humic substances and in vitro high-molecular compounds such as polysaccharides and proteins; and implementing membrane separation.