The growing environmental awareness, increasingly stringent environmental laws related to the discharge into surface waters, the need to reduce GHGs and energy consumption in wastewater treatment plants have led to the research for new and modern technology in this field. This master’s thesis focuses on the configuration, study and optimisation of a Membrane Aerated Bioreactor (MABR) - an innovative system that allows wastewater treatment with higher energy efficiency and much elevated nitrogen and COD removal rate, compared to the Conventional Activated Sludge reactor (CAS). The main principle of this reactor lies on the counter current supply of oxygen through a membrane, allowing a constant aeration for the biofilm which ensure the establishment of an aerobic zone for the nitrification and an anoxic zone for the denitrification, enabling the Simultaneous Nitrification and Denitrification (SND).