ABSTRACT
Most of the methodologies published in literature on wastewater minimization for batch processes are based on short-term scheduling techniques. When these methods are applied to longer time horizons, the computational time becomes intractable, hence the focus of this chapter. This chapter presents a methodology for simultaneous optimization of production schedule and wastewater minimization in a multipurpose batch facility. The key feature of the presented methodology is the adaption of cyclic scheduling concepts to wastewater minimization. The methodology is developed based on continuous-time formulation and the state sequence network (SSN) representation. The methodology is successfully applied to two common literature examples and an industrial case study to demonstrate its effectiveness. None of the currently published wastewater minimization techniques could solve the case study for a time horizon of 168 h. However, through the application of the presented methodology, a time horizon of 168 h for the case study was reduced to eight cycles with the cycle length of 23 h, for which the CPU time for the optimum cycle is 64.53 s.
