EN
Ammonia nitrogen is one of the factors, which impede nitrification process in activated sludge at Municipal-Industrial Sewage Treatment Plant (MISTP) in Oświęcim. As a result of this, completed tests were aimed to determine efficiency of this process at high ammonia nitrogen concentrations, in sewage being sent for biological treatment. Sewage used in the tests had the following concentrations of N-H4: 50.00 mg/dm3; 60.00 mg/dm3; 70.00 mg/dm3; 80.00 mg/dm3; 100.00 mg/dm3; 120.00 mg/dm3 and 140.00 mg/dm3. These concentrations simulated emergency sewage discharge into the system. The tests were carried out in parallel in two series, using activated sludge enriched with pure nitrifying bacteria cultures and sludge taken directly from the system, which constituted a control sample.