The Use of Simulation Modelling for Optimisation of Phosphorus Removal in Sewage Treatment under Varying Influent Loading

Abstract

A validated ASM2 model (STOAT) for the Changzhou WWTP was used to evaluate operational problems encountered in most wastewater treatment plants, during the transitional period from winter to summer. Favourable operating conditions which can achieve both TN and TP effluent concentrations under varying influent loading without the use of either chemical polishing or external carbon sources were established. Further, the use of 1.5 h wastage pump run time and 4.5 h cycle time was found better than the 3 h wastage pump run time and the 6 h cycle time as practiced in most WWTPs, as the latter is sufficient to allow second TP release, whereas the former is found to improve effluent TP by approximately 73%. The model was applied to troubleshoot another WWTP successfully. The finding in this study will improve the management of wastewater treatment plants for better and consistent effluent quality at a reduced capital cost.