In this study, a mathematical model was developed to have a better understanding of the process and be used in future reactor scale models to predict its process performance. This model utilizes the Activated Sludge Model NO. 1 (ASM1) framework and incorporates bioprocesses of formation and degradation of soluble microbial products (SMP) and extracellular polymeric substances (EPS). Simulation result shows the model could very well predict the bioreactor performance. The average error of COD, BOD and NH3-N removal efficiency was 0.48, 0.28 and 1.18%, respectively.