In this work, the effect of the improvement carried out at a large-scale wastewater treatment plant (WWTP) was evaluated, by means of modelling works, with the aim to determine the influence of the modernization over the process performance. After modernization, the energy consumption due to the aeration decreased about a 20% maintaining the effluent quality. In order to double-check the good effluent quality, modelling works were carried out at the full-scale plant. After calibration, the model was applied to the upgraded full-scale plant obtaining deviations lower than 10%. Then, the performance of the main biochemical processes was evaluated in terms of oxygen uptake rate (OUR), ammonia uptake rate (AUR), and chemical oxygen demand (COD) consumption. The rate of the main processes depending on the aeration, that is OUR and AUR, were about 22 gO2/(kg VSS·h) and 2.9 gN/(kg VSS·h), respectively.
Keywords: Activated sludge; aeration; modelling; wastewater treatment plant.