Although different systems of Constructed Wetlands (CW) for wastewater treatment have been in operation for more than 30 years, some aspects could still be much improved, such as the nutrients removal percentage and the avoidance of substrate clogging. This paper reports on an experiment conducted to assess the performance of a floating helophytes filter (FHF) to remove total nitrogen (TN) and the effect of supplemental aeration on nitrification and denitrification. The supply of external aeration to the FHF system reduced significantly (p<0.05) the TN final concentration in spring, summer, and autumn experiments, whereas in the winter experiment a strong N-NO^¯₃ accumulation was recorded in the FHF-aerated treatment that resulted in a poorer TN removal percentage (p>0.05). Low organic matter concentration is the most likely cause of the denitrification slowdown in the winter experiment.