The aim of this work is to present an overview about an experimental study for biological nitrogen removal implemented in a pilot-scale plant, located in the Universidad Del Norte in Barranquilla, Colombia. This plant was studied in two different periods. The first period, which was carried out in 90 days, was dedicated to study the influence of the daily variations on the influent and effluent wastewater, and prove some control routines for nitrogen removal. In the second period, which was carried out in 120 days, the removal process was optimized with the addition of acetic acid as an external carbon source, and the implementation of the final control strategy was performed based on the results of the previous period. [ABSTRACT FROM AUTHOR]