Forward osmosis feasibility and potential future application for desalination

Abstract

Forward Osmosis has been intensively investigated for seawater desalination in the past decade. However, the application of technology is still limited apart from a number of pilot and small commercial plants. Initially, forward osmosis was proposed as a breakthrough in the desalination technologies due to its potential for reducing the power consumption to the thermodynamic seawater limits. Lately, experimental studies have demonstrated that first insights underestimated the technology's energy efficiency and feasibility for desalination. Membrane fouling, back salt diffusion, membrane mechanical strength, draw solution, and many other factors were behind the loss of interest in forward osmosis technology. Conversely, field experiments have shown that forward osmosis membrane fouling was not a major problem, and water flux met the expectation when a full-scale hollow fiber membrane was provided. However, there were insufficient data regarding the cost and energy efficiency of the membrane regeneration stage. For thermal regeneration using a thermolytic draw solution, the major concerns were the ease of application and residual draw solution in the feed solution. The current study addresses the pros and cons of forward osmosis and the primary reason behind the technology being less successful, despite the large amount of money and efforts invested over the past decade.