Model development for simultaneous nitrification and denitrification

The aim of this study is to simulate the behaviour of nitrogen and carbon compounds in a sequencing batch reactor (SBR) by incorporating a dynamic microbial floc model. The results have shown that both floc diameter and liquid phase concentration are important factors influencing the internal floc reaction rate. An integrated model of the SBR has been proposed in this paper, whereby reaction rates are determined as a function of internal floc concentrations. This enables the evaluation of the phenomena that occur due to internal floc effects such as simultaneous nitrification and denitrification (SND). Results support the hypothesis that SND is a physical phenomenon, and occurs due to oxygen diffusion limitations within flocs.