Non-Fouling Ultrafiltration Membranes

Ultrafiltration membranes offer great potential for compact, low cost clean-up of Navy surface ship graywater and blackwater. A major limitation of these ultrafiltration membranes is significant loss in flux with time associated with membrane fouling from proteins, polysaccharides, and other waste products. Backflushing can only be used to a limited extent. Chemical treatments are undesirous since they pollute. ompact Membrane Systems, Inc. has developed unique low surface energy perfluoropolymer coatings. These perfluoropolymer coatings appear to be a universal non-fouling surface showing enhanced resistance to biological fluids (blood, platelets, SF-21, Vero cells) and oils and, therefore, should greatly enhance the ultrafilters fouling resistance. These perfluorocoatings represent a universal approach to enhancing ultrafilter resistance in that we have successfully coated numerous ultrafilters (polysulfone, cellulose, esters, polypropylene, PVDF). Preliminary results indicate that coating of ultrafilters with CMS perfluoropolymers can significantly enhance fouling resistance with little change in bulk flow. By using these perfluoropolymer coatings, we will enhance fouling resistance without introduction of chemical pollutants. In Phase I, we will: (1) coat various ultrafilters with our perfluoropolymers, (2) perform controlled internal laboratory evaluation of enhanced fouling resistance, (3) in conjunction with DoD, perform pilot operation with preferred candidate graywater, and (4) perform economic analysis based on results from (2) and (3). Objectives of Phase I are to demonstrate stable ultrafiltration capability in excess of 20 liters per square meter per hour using high density waste streams (15-20 grams/liter) for over 1000 hours of operation.