In reverse osmosis, salt water on one side of a semi-permeable membrane is subjected to pressure, causing fresh water to diffuse through the membrane leaving behind a concentrate stream. The concentrate stream contains the majority of the dissolved minerals and other contaminants, which needs to be safely disposed off.

Concentrate management can become one of the most important factors in determining the feasibility of a plant. Concentrate produced during seawater desalination can be disposed through deep well injection on land or returned to the ocean in a controlled process to avoid detrimental effect to the environment or marine life. For concentrates produced in inland facilities, a few other options exist. These include disposal to surface water bodies, evaporation ponds, or to wastewater treatment plants. In some instances, the concentrate can also be utilized beneficially for industrial processes.