Feasibility of rigorous multi-objective optimization of wastewater management and treatment plants

The present paper describes a study on the feasibility of coupling rigorous dynamic modelling (DM) and its extended boundaries through Life Cycle Assessment (LCA) with an Efficient Multi-Objective Optimization (EMOO) tool. The combined framework (DM-LCA-EMOO) was then applied to a real-world dynamic system: the wastewater treatment. To give a global view of all environmental, economic and technological performance, three objectives were considered: Effluent Quality Index (EQI), Operational Cost Index (OCI) and environmental impacts quantified through Life Cycle Impact Assessment (LCIA). Legally imposed constraints, including total nitrogen, total phosphorus, total chemical oxygen demand, total suspended solids and ammonium ion were also taken into account. Given the contradictory nature of objectives, the presence of constraints and the time-consuming simulation-based calculations, an Efficient Multi-Objective Optimization framework, namely Archive-based Multi-Objective Evolutionary Algorithm with Memory based Adaptive Partitioning of search space (AMOEA-MAP) was used. The practicality of such a combined DM-LCA-EMOO tool for the evaluation of wastewater management and treatment was then addressed and demonstrated through a case application