Design and Optimization for Generation of Efficient Wastewater Treatment Networks

Water is the most necessary commodity for survival for all forms of life around the world. Unfortunately, it is often undervalued and wasted, as those who readily have access to clean, safe water do not understand the magnitude of its importance. One of the main challenges that many nations around the globe are facing is the lack of access to clean water. Thus, providing clean water through wastewater treatment systems is a crucial step for continuing towards a sustainable future. Treatment depends on the wastewater constituents with properties like relative amounts, toxicity, size, and miscibility with water. Therefore, the development of a superstructure, consisting of all treatment methods and then reducing to the desired technologies in order to select the best route can prove most effective.

In this work, the technologies/methods involved in wastewater treatment such as sedimentation, filtration, membranes, adsorption, advanced oxidation processes, rotating biological containers, and activated sludge are modeled using the material and energy balance, equipment design, costing as well as environmental impact, which are in the form of linear and non-linear mathematical equations. Utilizing systematic programming methods, we frame the wastewater treatment network selection as an optimization problem for cost minimization, energy minimization along with sustainable goals.

We use representative case studies for municipal and pharmaceutical wastewater treatment and model them as optimization problems in the GAMS (General Algebraic Modeling Systems) programming language. In the next step, we use the P-graph approach for solving the same problem as this tool can provide insights into non-intuitive solutions, which will guarantee global optimality.

Keywords: contaminant properties, maximal structure, technology models, optimized selection, P-graph, sustainable process design.