Membrane desalination and water re-use for agriculture: State of the art and future outlook

Membrane-based desalination technologies for agricultural applications are widely applied in many countries around the world. Sustainable and cost-effective desalination technologies, such as reverse osmosis (RO), membrane distillation, forward osmosis, membrane bioreactor, and electrodialysis, are available to provide treated water, but the pure water product does not contain the required level of nutrients to supply agricultural fields. This can be overcome by the use of blended water to meet the required quality of irrigation water for crop production, which is expensive in areas lacking in freshwater resources. The adoption of a hybrid system offers many advantages, such as generating drinking water and water enriched with nutrient at low cost and energy consumption if natural power is used. This review focusses on summarizing the current and recent trends in membrane desalination processes used for agricultural purposes. The challenges being faced with desalinating seawater/brackish water and wastewater are discussed. A specific focus was placed on the viability of hybrid desalination processes and other advanced recovery systems to obtain valuable irrigation water. A comparison between various membrane desalination technologies in terms of treatment efficiency and resource recovery potential is discussed. Lastly, concluding remarks and research opportunities of membrane technologies are analyzed. We concluded that the ED process can be utilized to minimize the energy requirements of other membrane technologies. The MD coupled with ED system can also be utilized to generate high quality irrigation water at low energy requirement. The FO-ED hybrid system exhibited excellent performance and very low energy consumption as compared to other hybrid systems.