On the basis of the characteristics of magnetic flocs and cake layer in the magnetic enhanced flocculation membrane filtration (MEFMF) process

processes of on-line and off-line magnetic enhanced cleaning (MEC) were designed. Magnetic cake layer was separated from fiber surface under the synergistic effect of magnetic field force and aeration shear force

in which way the goal of optimization of membrane cleaning was achieved. The magnetic enhanced cleaning process was added to magnetic enhanced flocculation membrane filtration for off-line cleaning of fouled membrane module in MEFMF process. In the magnetic cleaning process with device's magnetic induction 6 mT

aeration intensity 500 L·m-2·min-1

washing time to 5 min

backwash pressure 0.04 MPa

optimum cleaning effect could be achieved for flux recovery rate over 97%. In the enhanced cleaning process with magnetic field the magnetic seeding in the cake layer was magnetized

rendering the cake layer weak macro magnetism. Under the effect of the attached magnetic field the magnetized cake layer moved to the pole

therefore

membrane flux recovery rate was increased significantly. Furthermore

on-line intermittent magnetic cleaning could be more effective in removing colloidal and organic pollutants on membrane surface in the MEFMF process. The colloidal and organic pollutants were the major pollutants blocking membrane pores and causing irreversible fouling. As a result

membrane fouling was mitigated during the entire process.