Modelling of the carrousel plant

Abstract

The results of experimental and mathematical modelling of simultaneous processes of organic and nitrogen impurities removal in an industrial Carrousel wastewater treatment plant are presented. The hydrodynamic regime measurements in the full-scale Carrousel system have led to the conclusion that at least three hydrodynamic models such as tank-in-series, ideally mixing reactor with aerobic and anoxic volume and completely mixing reactor with an intermittent aeration, are suitable to describe the dynamic behaviour of this bioreactor. The tank-in-series and the intermittently aerated completely mixing equipments were used in lab-scale modelling of the Carrousel plants. Various kinetic models and a statistical approach were applied to the evaluation of laboratory and full-scale data. The simplified kinetic model proved to be convenient for the process control purposes due to the significant computational time reduction in model parameters determination in comparision to tank-in-series hydrodynamic modelling. Also, the statistical model is very suitable approximation of the processes carried out in the Carrousel system. The completely mixing bioreactor with intermittent aeration is advantageous for experimental simulation of simultaneous nitrification and denitrification processes performed in high-rate recycled activated sludge systems. The influence of wastewater substances on oxygen transport rate is implicitly incorporated through aerobic and anoxic ‘switching functions’ evaluated based on oxygen profile data monitored in the bioreactor when applying the modified IAWPRC kinetic model.