Optimal design of water networks in process industries using mathematical model

This paper presents a mathematical programming model for the optimal design of water networks to achieve the minimum operating cost. The method combines water-using processes with wastewater-treating operations into a single network based on source/sink representation. The model, which contains all the network configurations of source-sink matches including reuse, regeneration reuse and regeneration recycle, also considering multiple contaminants, is formulated as a mixed integer linear programming (MILP) with topological constraints. The MILP model´s global optimality is guaranteed if a solution exists. Finally, a case study involving water reuse/recycle is implemented to show the effectiveness of the model. A considerable reduction of freshwater usage and wastewater discharge and optimal water network are obtained.