Modelling, simulation and optimisation of a large-scale reverse osmosis based on a high-salinity brackish water desalination process. Quantifying different grades of water

This study focuses on evaluating the performance of various proposed layouts of a multi-stage industrial large-scale Reverse Osmosis (RO) process, specifically designed to desalinate high salinity brackish water. The proposed layouts include the parallel, series, tapered layouts of retentate reprocessing, permeate reprocessing, and coupled retentate-permeate reprocessing. To conduct this study, a comprehensive validated model for a single RO membrane module found in the literature, which is then used to develop appropriate models for the proposed multi-stage RO system layouts. The proposed layouts are tested under unique inlet conditions to identify the design that performs optimally. The key performance indicators used for evaluation include water productivity, specific energy consumption, and product salinity. The results demonstrate variable productivity, product salinity and specific energy consumption for the proposed layouts. For each proposed layout, an optimisation study is conducted to instigate the optimal operating conditions to specifically producing a grade of water. Statistically, the optimisation results of tapered retentate permeate reprocessing layout elucidate the production of industrial water (less than 50 ppm) of 35.2% and 1.973 kWh/m3 of water recovery and specific energy consumption, respectively. Also, the same layout produces the optimum 72.32% and 1.623 kWh/m3 for bottled water (200 ppm). However, the tapered retentate permeate reprocessing layout introduces optimum 64.98% and 1.688 kWh/m3 for tap and drinking water (500 ppm), 58.128% and 1.353 kWh/m3 for irrigation water (800 ppm), and 47.474% and 1.238 kWh/m3 for livestock water (1000 ppm). Thus, this study introduced the possibility of producing different grades of water including industrial water, bottled water, tap water, irrigation water, and livestock water.