Reverse osmosis pretreatment technologies and future trends: A comprehensive review

Abstract

Recent progress in reverse osmosis (RO) technology is not limited to RO membrane materials, module designs and RO process optimization. It involves prior feed treatment which directly impacts RO system performance. The ongoing challenges of membrane fouling in RO membranes can be addressed by increasing the operational efficiency through the use of correct pretreatment options which can mitigate organic and inorganic fouling by selectively rejecting contaminants prior to reaching the RO unit. Highly polluted water resources have put critical stress on the existing conventional pretreatment techniques, whereby membrane pretreatment has emerged as a promising alternative. This paper provides an overview of the development and current trends in conventional and nonconventional RO pretreatment techniques whereby the techniques are critically reviewed to 2 inform readers of potential improvements in such areas. This paper addresses the major drawbacks of conventional pretreatment methods which have necessitated the use of membrane pretreatment techniques. Special attention is given to microfiltration, ultrafiltration and nanofiltration methods and their development in terms of advanced membrane materials based on ceramics and self-cleaning membranes. Studies from laboratory scale standalone systems, pilot scale and large scale integrated systems for performance, cost and ecological analysis have been reviewed to familiarize readers with the many factors which need to be analyzed for selection of the appropriate pretreatment method(s). The critical review in this paper will help researchers focus more on the areas which have room for further development for cost-effective and advanced RO pretreatment techniques.

Reverse osmosis desalination: A state-of-the-art review

“…On the other hand, current research interests are directed towards improving self-cleaning membranes [391]. Examples include the self-cleaning membrane created through coating the RO membranes with TiO2 [392].…”

“…Many researchers are heavily concerned with improving the overall operation of the RO systems through improving the pre-treatment systems in order to minimize membrane fouling and scaling and improve the removal of suspended solids and dissolved organic matters. RO pre-treatment technologies may be either conventional including coagulationflocculation, media filtration, disinfection, scale inhibition or non-conventional such as MF, UF, and NF [145,391,[393][394][395]. As per the available literature, UF, MF and coagulation-flocculation are considered the most widely used pre-treatment technologies.…”

Gypsum Crystallization during Reverse Osmosis Desalination of Water with High Sulfate Content in Presence of a Novel Fluorescent-Tagged Polyacrylate

“…Reverse osmosis (RO) is becoming recently a powerful technology for the purification of sea, brackish and waste water [1][2][3][4]. However, one of the major limitations in efficient RO application is the membrane scaling [5][6][7].…”

Characterization of seawater reverse osmosis fouled membranes from large scale commercial desalination plant

“…Generally, during the formation of fouling layers on the membrane surface can beg and generate the back diffusion of dissolved salt ions which generates an increase in the concentration of salt ions on the side of the membrane surface. Results revealed that the membrane performcae may change due to organic and inorganic matter in water during osmosis process, which needs to tackle by modifying the membrane with advanced material (Anis et al, 2019;Badruzzaman et al, 2019;Croll et al, 2019;Ghaemi and Khodakarami, 2019;Ghaseminezhad et al, 2019;Joseph and Damodaran, 2019;Liu et al, 2019;Nguyen et al, 2019;Rehman et al, 2019;Shakeri et al, 2019;Tang et al, 2019;Weinman et al, 2019;Zou et al, 2019).…”