Igor Plazl, Tine Koloini
Department of Chemical Engineering, Universty of Ljubljana, Aškerčeva 5, 1001 Ljubljana, Slovenia

Meta Levstek, Olga Burica, Marjetka Stražar
Domžale-Kamnik Wastewater Treatment Plant, Študljanska 91, 1230 Domžale, Slovenia


In modern wastewater reactor technology dynamic modelling proved to be a valuable tool for the simulation of wastewater treatment performance, especially in cases of problematic inflow characteristics and no optimal process conditions. Due to stringent EU legislation the Domžale-Kamnik WWTP of 200,000 PE is confronted with the need to upgrade the plant in the sense of nutrient removal.
As the full-scale plant is also subject to changing process conditions, a CSTR pilot plant of 15 liters was installed. The system was operated in the single sludge mode at the specified process conditions (temperature, dissolved oxygen, flow, recycle ratio), and was fed with artificial wastewater. The effluent composition (organic nitrogen, ammonium, nitrate, COD), some stoichiometric and kinetic parameters, and operation parameters of the pilot plant were determined in the laboratory by standard laboratory methods. These results served as input parameters for the calibration of the steady-state model based on real conditions according to IAWQ model No.1.
The dynamic response to a step disturbance of the input flow was measured and comparison between dynamic response of the calibrated ASM1 model and experimental data is represented. The disagreement between the experimental and by model predicted results can be explained with ASM1 limitations.