The hollow fiber ultrafiltration membrane with inner skin was prepared by controlling the external coagulation condition from one or two polymer dopes with dual or triple-orifice spinneret. It was successfully used for the treatment of the wastewater from banknote printing works after characterizing the foulant and finding a suitable cleaning method, for the preparation of polyaluminum chloride (PAC) with high Alb content and the synthesis of nanosized BaSO4 and CaCO3 particles by a membrane reactor.