Study of Backwashing Process for Ceramic Micro-filtration Membranes Used in Pretreatment of DMF Wastewater

摘要

DMF wastewater from the PU synthetic leather industries was filtrated by ZrO_2 micro-filtration membranes with an average pore size of 0.2μm. The membrane fouling mechanism was analyzed by resistance-in series model. The results indicated that the resistance from the particles sedimentation on membrane surface accounting for 76% of the total resistances. The technology of backwashing was a stable, valid and reusable method to recover the membrane flux in the micro-filtration. During backwashing, the reverse flow through the membrane removes the concentration polarization and cake or gel layers from the membrane surface. The effect of the backwashing conditions on the flux was studied. The obtained optimization conditions were as follows: backwashing pressure 0.6 MPa, backwashing time 5s and backwashing interval 20min. The permeate flux could be raised about 50% compared with that without backwashing.