<p>This study is interested in the optimization of energy consumption in activated sludge systems, taking as a case study the Souk-Ahras Wastewater Treatment Plant, North-eastern Algeria. Minimization of the dissolved oxygen content capable of achieving the functioning conditions of the required treatment quality was considered as energy consumption is directly related to dissolved oxygen concentration in the biological reactor. An activated sludge model (ASM1), tuned by several fractions according to the various reactions with microorganisms, and the simulator (GPS-X) were considered in the simulation process. ASM1 and GPS-X are used to estimate the impact of numerous strategies and scenarios of regulation of aeration on the treatment performance and the energy consumption of the activated sludge process of the Souk-Ahras Wastewater Treatment Plant (WWTP). The kinetic parameters of the ASM1 model were obtained via calibration of the nitrification–denitrification model. Parameters obtained by calibration and later checked in the validation phase were subsequently used to test a prospective scenario that leads to the reduction of energy consumption. The obtained results indicate a reduction of 31% of energy consumption, while maintaining a minimum concentration of dissolved oxygen of 0.2&#xa0;g/m³ in the biological reactor. The activated sludge process maintains a high level of treatment effectiveness across the tested dissolved oxygen range, with a treatment efficiency, ranging from 90 to 98%. This would imply that, even at the lower end of the dissolved oxygen concentration (0.2&#xa0;g/m³), the system continues to perform well.</p>