The Ultrafiltration of Return Sludge through Ceramic Membrane

Abstract

To expand the use of ceramic membrane, the ultrafiltration of return sludge has been carried out. The return sludge was obtained from two plants of activated sludge process. A membrane module, in which a tubular ceramic membrane was inserted, was set up for ultrafiltration. The values of volume flux through membrane were measured under different conditions of gauge pressure, feed velocity, and Mixed Liquor Suspended Solid (MLSS) of return sludge. The following results were obtained: ( 1 ) the volume flux was not influenced by gauge pri'ssure and MLSS: (2) the volume flux increased with increasing feed velocity. It was speculated from above results that a sludge layer might be formed on the surface of ceramic membrane under ultrafiltration. The volume flux was found to be recovered up to 81∼91% by washing with NaClO solution.