Investigation on salt separation and water recovery in the process of seawater reverse osmosis using cooling water of power plant

In recent years, the waste energy in cooling water of power plants has been applied for the production of water from saline waters. In this research, the effect of using the cooling water of a power plant located on the Persian Gulf coast, as a feed of a reverse osmosis unit was investigated on the separation of salt from seawater, the quality of the final product and water recovery. By increasing the feed water temperature from 20 to 45 °C, although the flow of the produced water increased about twice (from 7.5 to 14 L/m2h), it decreased the membrane salt rejection and salt separation by the membrane. As a result, the electrical conductivity of the produced water increased to about 700 to 1200 μS/cm. This change is due to enhanced membrane permeability to water and salt at higher water temperatures. Increased water flux saved energy for water production, but reduced the desirability of drinking water, although it remained within the world health organization (WHO) standards.