A new integrated MBR model for wastewater treatment: sensitivity and uncertainty analysis

In this study a new integrated membrane bioreactor (MBR) model is proposed. The model is able to describe the main biological processes aimed at the carbon and the nutrients (nitrogen, N and phosphorus, P) removal coupled with the soluble microbial products (SMP) formation/degradation. Furthermore, the model describes the key physical processes and the interconnection between SMP and membrane fouling. The model was calibrated by adopting data measured during the monitoring of a University Cape Town (UCT) MBR pilot plant. A sensitivity analysis allowed the reduction of the number of model FACTORs to be calibrated from 122 to 45. A good correlation between measured and simulated data was obtained for the calibrated model (the efficiency of the calibrated model was 0.56). The detailed description of the nitrogen transformation bioprocesses (nitrification/denitrification) allowed improvement of the model accuracy - a narrow uncertainty band width was obtained for N related model outputs. Globally, 90% of measured data lay inside the uncertainty bands.