Global demand for water is increasing as many countries are experiencing large population growth. Even in countries where the water supply is adequate, people are beginning to realize how precious it is. As a result, many countries are developing ways to increase and conserve their supplies of fresh water.
One such solution is desalination, the process by which salt water is converted into drinkable fresh water. This involves the removal of salt compounds and other chemicals from the salt water, a process which has traditionally been carried out by heating the water (the thermal method). The main disadvantage of this method has been the cost. Consequently, a cheaper and more flexible method has been developed, whereby salt water is purified by passing it through filters. This method is used most effectively in combination with the thermal method.