Sustainable Design and Synthesis of Hybrid RO-PRO Systems for Industrial Wastewater Treatment

Abstract

Pressure retarded osmosis (PRO) is a new technology can provide sustainable power to many processes. However, the optimal design methods of integrating this technique in practical processes are rarely reported in literatures. This work addresses the problems of sustainable design and synthesis of reverse osmosis (RO)- based wastewater treatment process powered by PRO. A novel superstructure optimization method is proposed to solve the problem, where the superstructure for a RO-PRO hybrid system is enhanced with additional features from industrial wastewater streams. The problem addressed is formulated as a mixed- integer nonlinear programing (MINLP) model. A case study on industrial wastewater desalination is carried out to show that the proposed approach can identify optimal designs for reducing the specific energy consumption of membrane-based treatment systems, especially in desalination applications. Besides, from the standpoint of life cycle assessment, the global-warming potential (GWP) has a 34.8 % of CO₂ reduction (from 1.299 kgCO_2eq /m³ for the stand-alone RO system to 0.963 kgCO_2eq /m³) for the hybrid system.