Brackish water’s salinity range between seawater and fresh water. It is less saline than seawater, but is more saline than fresh water. This often occurs, such as in estuaries, where the river meets the sea. Most water habitats, in fact, are surrounded by brackish bodies of water, such as the Black Sea, Lake Monroe in Florida, the Amazon River, and the Hudson River in New York.
Brackish water can be made potable through desalination using the reverse osmosis water filter system. Desalination is the process of separating salt from the water molecules. Brackish water is also known as the stream of saline feedwater, which is water that comes from the ocean or underground.
In the reverse osmosis filtration system, saline water goes through four processes: pretreatment, pressurization, membrane separation, and post-treatment stabilization. On the pretreatment stage, feedwater is pretreated by removing solids. The pH level is also adjusted, and threshold inhibitors added to match the requirements of the RO system’s membranes.
The pump raises the pressure during the pressurization stage—the rate of pressure depending on the membrane and the salinity of the pretreated water. The separation stage is next where the membrane filters the salt, while allowing desalinated water to pass through. The desalinating process ends with the stabilization stage. Before the desalinated water can be qualified or approved for consumption, the water goes through an aeration column where the pH is elevated and stabilized between 5 and 7. The water can now be used as potable water, as well as for industrial and agricultural use.