Rotating Membrane Filter Cuts Energy Costs

Description And Advantages

A membrane filtration system that promises to cut energy costs by 80-90% from those of conventional cross flow membranes has been developed by the Fraunhofer Institute Interfacial Engineering and Biotechnology, Germany. Now being tested with municipal waste water at the laboratory scale, the equipment has application in process industries for solid-liquid and oil-water emulsion separations.

The system consists of a stack of circular, porous ceramic discs, mounted on a vertical, rotating, hollow shaft. Wastewater is pumped into the top of the unit and passes horizontally over the rotating membranes,, which create a flow within the wastewater. By adjustment of the reaction rate (typically a few hundred rpm), the buildup of solids on the filter can be regulated to minimize clogging. The filtrate passes through the membrane pores and is drawn off through the hollow shaft. The rejected solids are thrown to the wall by centrifugal force and fall down, to be removed at the bottom. As a result, the energy intensive pumps needed to backwash conventional systems are avoided.

Source: Chemical Engineering, July 2001.