Desalination Pretreatment Technologies: Current Status and Future Developments

Abstract

Pretreatment of raw feed water is an essential step for proper functioning of a reverse osmosis (RO) desalination plant as it minimizes the risk of membrane fouling. Conventional pretreatment methods have drawbacks, such as the potential of biofouling, chemical consumption, and carryover. Non-conventional membrane-based pretreatment technologies have emerged as promising alternatives. The present review focuses on recent advances in MF, UF, and NF membrane pretreatment techniques that have been shown to be effective in preventing fouling as well as having low energy consumption. This review also highlights the advantages and disadvantages of polymeric and ceramic membranes. Hybrid technologies, which combine the benefits of conventional and non-conventional methods or different membranes, are also discussed as a potential solution for effective pretreatment. The literature that has been analyzed reveals the challenges associated with RO pretreatment, including the high cost of conventional pretreatment systems, the difficulty of controlling biofouling, and the production of large volumes of wastewater. To address these challenges, sustainable hybrid strategies for ceramic membrane-based systems in RO pretreatment are proposed. These strategies include a thorough assessment of the source water, removal of a wide range of impurities, and a combination of methods such as adsorption and carbon dioxide with a low amount of antiscalants. Furthermore, the suggestion of incorporating renewable energy sources such as solar or wind power can help reduce the environmental impact of the system. A pilot study is also recommended to overcome the difficulties in scaling ceramic systems from laboratory to industrial scale. The review also emphasizes the importance of conducting an effective assessment to suggest a treatment for the brine if needed before being discharged to the environment. By following this framework, sustainable, energy-efficient, and effective solutions can be recommended for pretreatment in desalination systems, which can have significant implications for water scarcity and environmental sustainability.

Nanofiltration Ceramic Membranes as a Feasible Two‐Pronged Approach toward Desalination and Lithium Recovery

“…Desalination is one of the key solutions to meet the ever‐increasing demand, with an estimated global production of 90 million m 3 freshwater per day. [ 4 ] Typically, seawater desalination accounts for the majority (≈60%) of global desalination processes, while brackish groundwater desalination accounts for ≈20%. [ 5 ] Over the past two decades, thermal desalination has been gradually phased out due to the high energy demands required to evaporate seawater into vapor.…”

“…[ 19 ] Other tangible benefits of using ceramics over polymers in the context of nanofiltration include higher water permeability, higher mechanical strength, increased temperature resistance, the absence of pore swelling, and insensitivity toward salinity. [ 4 ] Modifying the conventional polyamide membrane to overcome each of the drawbacks is arguably a fundamental challenge, and each additional layer of modification introduces a new level of complexity in the fabrication process. Therefore, the multitude of advantages of ceramics make it appealing for further development in nanofiltration applications.…”

Co-Al layered double oxide activated carbon composite for eliminating lead ions from water

“…In the water environment, various contaminants have been detected and reported to cause pollution and serious human diseases [1]. Heavy metals, organic wastes, radioactive wastes, and pharmaceuticals are among the major pollutants that gained considerable attention due to their severe impact on the human body and the ecological system [2].…”

Ex Situ and In Situ Organic Fouling Monitoring in Laser-Induced Graphene-Based Electroconductive Membranes for Desalination and Wastewater Treatment

“…Membrane technology is one of the advanced technologies for desalination, water, and wastewater treatment, providing various advantages, including a smaller footprint, better water quality, and lower operational costs over conventional methods. − Microfiltration (MF) and ultrafiltration (UF) are very useful in various fields, including water and wastewater treatment, desalination, biomedicine, air purification, and food and chemical processing due to their good separation capability and low-pressure requirement. ,, MF and UF are also the most widely used pretreatment methods for desalination and wastewater treatment. , Pretreatment of feedwater for reverse osmosis (RO)-based desalination plays a significant role in their performance and efficiency. Hence, for industrial use and on a large scale, pretreatment technologies are often integrated with desalination plants. , This helps the desalination plant function properly and maintains the feedwater quality as per the standards. , However, fouling of these membranes is inevitable, leading to a decline in flux, deteriorated permeate quality, increased operational costs, and reduced membrane life span. , Fouling of the membranes can occur via adsorption on the membrane’s surface and/or inside the pores, leading to a loss in flux. , After a threshold level of fouling, the membrane loses its permeability, requiring replacement and causing an increase in operational cost . To reduce the cost associated with the replacement of fouled membranes, membrane cleaning techniques like cross-flushing, backwashing, and chemical cleaning are commonly used .…”