Reverse Osmosis Desalination and Hybrid Membrane Processes for Brine Treatment

Abstract

Waste from seawater reverse osmosis desalination processes is commonly referred to as brine which is one of the obstacles creating environmental and economic inefficiencies. The objective of this work is to simulate the hollow fiber reverse osmosis desalination membrane process to quantify its brine volume and concentration. Then, the pervaporation process and membrane distillation process are simulated to study and compare their brine treatment capabilities.

An accurate model is identified and used to represent the hollow fiber reverse osmosis process. Then, the models for pervaporation and membrane distillation are studied separately and the most accurate ones are selected to represent each process. After that, the models are arranged in an order to minimize brine volume so hybrid models are created. Finally, simulation studies are carried out to evaluate the physical parameters for the hybrid processes and to calculate the quantity and quality of brine left.

This simulation study involves solving multiple differential equations simultaneously to study the real-time change in the physical parameters such as permeance, concentration, and pressure drops. Therefore, the equations are solved in Python programming language. And the generated data are stored in Microsoft excel sheets to easily deal with the data.

The simulation studies show that both pervaporation and membrane distillation has good potential to be used in treating seawater reverse osmosis brine. However, pervaporation showed higher permeate water quality than MD with a 20% reduction in brine volume per stage. On the contrary, membrane distillation showed higher water flux with a 25% reduction in brine volume per stage. Finally, both pervaporation and membrane distillation membranes are capable of treating brine up to 200,000 ppm.