Nowadays, population growth and per capita global demand for fresh water, droughts arising from global changes, and the growing need for water in industry and agriculture highlight the importance of dealing with water crisis. Water and energy are two basic needs in today's world to sustain human life. The growing need for fresh water has led to the widespread use of desalination systems. Ground waters and low-salinity rivers (brackish waters) are among the main sources of drinking water around the world, which are required to be desalinated to meet predetermined drinking water standards. In this respect, various desalination processes have been developed so far to obtain fresh water from saline resources of water such as seawater and brackish water. The process of removing salts from water, which usually contains a high concentration of salt, and producing fresh water is called desalination. One of the most common methods in desalination of brackish water is the electrodialysis membrane process. In terms of energy, a variety of renewable energy sources are emerging to secure the future of mankind. One of these energy sources is salinity difference as clean and renewable energy. One of the most important methods in obtaining energy from salinity difference is the reverse electrodialysis process, which is structurally similar to the electrodialysis process.
In this study, the possibility of preparing fresh water through environmental friendly process of hybrid electrodialysis (ED)-reverse electrodialysis (RED) has been investigated. Therefore, the process performance has been evaluated with regard to both desalination and energy generation. Besides, the process has been modeled with real and synthetic concentrated brine with high salinity of up to 200,000 ppm from Persian Gulf seawater and synthetic and real brackish water with the salinity of up to 7,240 ppm from rivers in Bushehr province, Iran. Results demonstrated that the RED system was capable of generating the