Biosorption is becoming increasingly important for the treatment of pollutants due to its cost-effectiveness, environmental friendliness and efficiency. For a more sustainable environment, more studies need to focus on the application of real industrial effluents. Increasing the initial concentration of activated sludge increases the specific surface area of the sludge, which allows for greater sorption of sorbates. The optimal initial concentration of activated sludge in the process of biosorption of pollutants from pharmaceutical effluent was 5.12±0.13 g/L. The biosorption process can be described by the Temkin model, where the estimated values of BT and AT ranged from 29.11 to 76.08 and from 1.10 to 1.48 L/g, respectively. The overall efficiency of the biosorption process ranged from 9.5 to 40.2%. The removed toxicity averaged 41.1±7.88% for all experiments.