Solid-liquid separation method and apparatus for biological treatment liquid of organic wastewater

摘要

PROBLEM TO BE SOLVED: To provide a solid-liquid separation method for biologically treated sewage capable of obtaining stable clear filtrate at high speed and a low running cost by using a small-sized apparatus without clogging of a filtration film, and an apparatus therefor. SOLUTION: In this solid-liquid separation method for organic biologically treated sewage, after introducing fibrous SS and BOD-containing organic wastewater into an aeration tank and the wastewater is biologically treated therein, the biologically treated liquid is made to flow into a filtration and separation tank where a water-permeable filtration element is dipped in the biologically treated liquid. An inorganic coagulant is added to the treated liquid to coagulate the fibrous SS. The coagulated mixed liquid is filtered by the water-permeable filtration element to form a dynamic filtration layer of the coagulated sludge on the surface of the water-permeable filtration element. The filtrate is obtained from the water-permeable filtration element at water head pressure.