A novel process for the treatment of municipal and industrial wastewater is developed, which leads to the direct production of electricity, and/or H-2, by an environmentally friendly way. Through this process, production of electricity is obtained by a novel direct-biogas-fuelled fuel cell, which is also developed here, that concerns a major subunit of the overall process. Both intermediate and high temperature solid oxide fuel cells (IT- and HT-SOFCs) based on 10mol% Gd2O3 doped CeO2 (gadolinia doped ceria, GDC) and 8mol% Y2O3 stabilized ZrO2 (yttria stabilized zirconia, YSZ) solid electrolytes, respectively, have been constructed and tested, while three different Ni-based cermets were used as anodic materials. The operation performances of these cells under direct feed of simulated biogas mixtures are comparatively discussed. (C) 2007 Elsevier B.V. All rights reserved.