The present invention relates to the development of high flux hollow fiber ultrafiltration membrane prepared from poly (acrylonitrile-co-methacrylic acid), (polysulfone and poly (acrylonitrile-co-methacrylic acid)) and (polysulfone and ion exchange resin (sulfonated polystyrene-divinyl benzene copolymer)) blend and the point-of-use filtration unit there from for water purification and disinfection. The developed membrane has an active layer with pore size which effectively rejects pathogens and other bacteria from contaminated water while allowing the passage of water to produce biologically pure water for drinking. Therefore, the present invention relates to development of hollow fiber ultrafiltration membrane that delivers biologically pure water at a desirable rate, that is at a rate 25-200 liters/m2.h. The membrane performance in terms of flux and rejection efficiency is dependent on polymer material type and surface properties. The hollow fiber membrane with interpenetrated structure prepared from a blend of polysulfone and a copolymer of acrylonitrile and methacrylic acid is advantageous over the membranes made either from polysulfone or the copolymer alone in terms of durability, strength, elasticity, smoothness, flux, separation efficiency, fouling resistance properties. The surface modified blend membranes with acid groups which have smaller pore size and surface charge exhibit further improvement in the separation efficiency. Using the hollow fiber membranes a point-of-use water filtration unit which is simple, compact, inexpensive device that does not require electricity has been developed to produce 150-300 ml/min product water when attached to a tab from overhead tank of about 3 meter height.