A review of efforts to reduce membrane fouling by control of feed spacer characteristics

Abstract

A major problem for the operation of membrane based water treatment systems is fouling of the membrane surface. Within industrial modules, such as spiral wound modules, feed spacers are necessary to separate adjacent membrane layers. Engineering of feed spacers with novel characteristics is an attractive option for reducing fouling within the module, for instance by increasing surface shear forces. This paper reviews the characteristics of feed spacers which are important in fouling and efforts to design novel feed spacers with anti-fouling characteristics, such as by addition of surface coatings, modified feed spacer design and geometric considerations, 3D printing and use of electrically conductive feed spacers. This paper also provides a brief review of techniques available to assess aspects of feed spacer design. It is seen that appropriate feed spacer design can do much to mitigate fouling in membrane modules, but continued effort is needed toward enhancement of high flux and low-pressure drop in membrane modules.