An Efficiency-CentredHierarchicalMethod toAssess Performance of WastewaterTreatment Plants

An efficiency-centred hierarchical model is developed to assess the performance ofwastewater treatment plants (WWTPs). Specifically, a new treatment performance index (TPI) hasbeen proposed to determine the overall treatment performance of WWTP by analysing the TPIvalues and the weights of individual treatment phase for overall treatment performance. Threemodules have been developed to examine the performance of the primary, secondary, and tertiarytreatment units of aWWTP. Themodel is applied to threeWWTPswith different scale, loading rate,capacity, and process phases. The case study results indicate that the developed tool is useful inassessing the WWTP system in terms of treatment efficiency, operating conditions, and costeffectivenessof its management schemes. The model can be also combined with an infrastructurecondition rating index model to form a condition rating model for a WWTP, and used as a costeffectivetool to evaluate current and future needs in operation and management.