The Retrofit Design for Water Network with Multiple Contaminants of Industrial Process

Water is the important resources for process industry. The reduction of water usage decreases the capital cost for process industry. This paper presents a design model of water/wastewater network with multiple contaminants. The main purpose is minimizing the total fixed cost (TFC) and the total annual cost (TAC) of overall water network including annual cost of water usage and water treatment compared between two design models. The first model is retrofit design of water network model by a liner programming (LP) for design with treatment. The second model is simultaneous grassroots design of water/wastewater network with minimum TAC by a mixed-integer non-liner programming (MINLP). According to the main purpose, a non-linear programming (NLP) model is solved for good initial variables for the MINLP in the second model. This model uses data from published work. The result show the grassroots design of water/wastewater network can reduce TAC more than one from the retrofit design. All mathematical models of this work are solved by DICOPT as solver in General Algebraic Modelling System (GAMS).