The feasibility and optimization of low-cost nanofiber-membranes as potential MBR-membranes is studied. The nanofiber-membranes have a unique surface architecture, a high surface porosity and permeability and adjustable pore sizes. The materials, their heat treatment as well as the diameters and area-weights of nanofiber sheets were optimized. The comparative performance of a nanofiber-membrane to lab-made polysulfone (PSF(L)) and commercial polyvinylidene fluoride (PVDF(T)) and polyethylene (PE(K)) membranes was performed. The critical flux (CF) and trans membrane pressure (IMP) profiles were used as evaluation parameters. A heat treatment was efficient to prevent layered fouling on the nanofiber-sheets. The electrospun nanofiber-membranes showed performances comparable to those of the tested commercial membranes at short and long term. Further developments on nanofiber-membranes are still required to further improve their performance and enhance their competitiveness in MBRs applications. (C) 2011 Elsevier B.V. All rights reserved.