Optimization of hybrid system consisting of forward osmosis and reverse osmosis: a Monte Carlo simulation approach

Abstract

Forward osmosis (FO) is a membrane process that has been studied as novel technology for treatment of a wide variety of aqueous solutions. FO uses a semi-permeable membrane to extract cleaning water from impaired water by an osmotic pressure gradient but it also needs to have a posttreatment so-called “draw solute recovery.” The focus of the current study was to investigate a FO–reverse osmosis (RO) hybrid process in which RO is being used to recover draw solutes in product water from FO. A Monte Carlo method was applied to optimize the system. The key parameters affecting the energy efficiency of the hybrid system were also identified. The results indicated that the FO–RO hybrid system has advantages over RO-only system under high fouling conditions. It was found to be essential to minimize the internal concentration polarization to ensure high-energy efficiency and smaller requirements of membrane surface area.

Keywords:

• Forward osmosis
• Reverse osmosis
• Hybrid process
• Draw solutes
• Monte Carlo simulation
• Optimization

Acknowledgment

This research was supported by a grant from the WPM research program by the Ministry of Knowledge Economy, Republic of Korea.

Notes

The 4th International Desalination Workshop (IDW4), 16–18 November 2011, Jeju Island, South Korea