Desalination means removing the mineral components from the sea water and transforming the sea water to usable water. The fresh water is increasingly becoming scarce, therefore more and more states are considering the option of desalination of seawater.
The major disadvantage of seawater desalination is that the process is not energy efficient. The seawater is pushed through a membrane from which only water molecules can pass, salt and minerals do not pass through it. This process is known as reverse osmosis and uses about 3 to 4 times more energy as compared to treatment of equivalent amount of groundwater, releasing a large amount of CO2 in the atmosphere.
Therefore, the correct answer to this question is:
Reverse Osmosis
