6. Scenario Analysis for the Multi-objective Management of Municipal Wastewater

The ultimate purpose of model construction and simulation is not merely prediction; more importantly, they enable the simulation and assessment of policies formulated by policymakers. Within this context, a scenario analysis method has been proposed. A scenario is not a single prophecy or prediction; it provides plausible directions and trends for future development. During scenario design, each designer conceives and envisages the future blueprint, or more precisely, develops a future development concept. Therefore, a retrospective analysis of the objective development history is required before scenario definition and construction. Subsequently, a set of reasonable, generally accepted, and justifiable assumptions or confirmed future prospects should be developed. Finally, the possibilities of achieving the prospects and measures that must be adopted are analyzed (Khan et al. 2017). The greatest difference between scenario analysis and conventional prediction methods is that the scenario analysis involves the investigation of future situations that may occur under certain presuppositions and the conditions that lead to these situations, while prediction merely attempts to describe situations that are most likely to occur in the future (Wang et al. 2018).