ELECTROOSMOTIC MEMBRANE BACKWASHING

Membrane fouling is a limitation on the efficient use of membrane microfiltration and especially if it occurs within the pores, as the use of cross-flow of the process feed is then not effective. In-pore foulants may be removed by backwashing membranes. The paper reports an experimental study of the effect of backwashing induced by the use of applied electric fields, electroosmotic backwashing. It is shown that electroosmosis is a very effective means of producing high shear stress at the pore walls of microfiltration membranes. This can result in the restoration of up to 97 % of the initial water flux for the case of membranes which have become severely fouled by the in-pore deposition of proteins. Comparison shows that electroosmotic backwashing is more effective than pressure-driven backwashing. The advantages become more marked with repeated filtration/backwashing cycles. Electroosmotic membrane backwashing is a promising process meriting further investigation.