Hybrid PAC-submerged membrane system for trace organics removal II: System simulation and application study

The hybrid powdered activated carbon (PAC)-submerged microfiltration hollow fiber membrane system with air bubbling has been simulated at two operation strategies of batch and continuous PAC dosing for trace organics removal from water. The mathematical models were developed based on corresponding solute mass balance equations and the homogeneous surface diffusion model (HSDM), where the two kinetic parameters Ds and kf were obtained in Part I of this study. After verification with experiments using atrazine as the model trace organic compound, the developed models were used to predict the product water quality at various operating conditions. It was found that at the batch PAC dosing mode, the trace organic removal can be improved by increasing the bubbling rate or increasing the operation flux. While at the continuous PAC dosing mode, the target compound removal is independent on the bubbling rate, which suggested the possibility of reducing energy consumption by inducing a low bubbling rate. Besides, lower operation flux shows more benefit because of the longer hydraulic retention time. The simulation can provide a better understanding of the system and assist in evaluating various operation strategies properly.