Applications of Reverse and Forward Osmosis Processes in Wastewater Treatment: Evaluation of Membrane Fouling

Abstract

Although reverse osmosis (RO) process is widely used for wastewater reclamation, it requires high amount of energy that has a major effect on the economic effectiveness of the process. Furthermore, RO membranes are susceptible to fouling, which further limits their effectiveness and increases the costs due to the need for frequent cleaning.Consequently, the use of osmotically driven membrane separation processes such as forward osmosis (FO) has gained increasing consideration, although its uptake in wastewater remediation is still low. This is because the FO process, unlike the RO process, is operated by the osmotic gradient between the feed and draw solutions; therefore, it requires minimal or no hydraulic pressure. Hence, it has unique advantages, such as possibility of low fouling, and high water recovery. Nonetheless, the long-standing problem of membrane fouling still remains a major challenge even in the performance of FO processes especially when treating raw wastewaters, which have various contaminants. Furthermore, the mechanism of fouling in FO process has been found to be different from an RO process, and there is need for further studies to elucidate the differences of FO and RO fouling. These aspects are evaluated in this review.

Microwave Synthesis of Poly(Acrylic) Acid-Coated Magnetic Nanoparticles as Draw Solutes in Forward Osmosis

“…This adaptability and design simplicity contribute to lower installation and maintenance costs of FO devices. The combination of low energy consumption, cost-effective operation, high water recovery, reduced membrane fouling propensity, and a simple and adaptable system design positions FO as a promising technology for advanced water treatment [5,[17][18][19][20]. The effectiveness of the FO process in water production heavily relies on the properties of the DS.…”

Structure Dependent Water Transport in Membranes Based on Two-Dimensional Materials

“…Comparing the molecular scale membrane processes with that of the pressure driven, nanofiltration membranes are used to remove heavy metals, harmful organic macromolecules, multivalent salts, varying amounts of monovalent salts, and reverse osmosis membranes in addition removes nitrates, sulfates, turbidity, color, and even salt from feedwater streams, rejecting almost all ions in a feed stream, and simultaneously showing apt water flux, ensuring enhanced performance, gathering capital for industrial applications. 12 Lately, the process of forward osmosis has effectively upsurged the research for water treatment 13,14 and desalination, 15 owing to a higher recovery rate and water flux, in comparison to other pressure driven membrane processes. However, the RO processes currently dominate the market worldwide.…”

“…Lately, the process of forward osmosis has effectively up-surged the research for water treatment , and desalination, owing to a higher recovery rate and water flux, in comparison to other pressure driven membrane processes. However, the RO processes currently dominate the market worldwide.…”