Desalination of Sea Water

Desalination of Sea Water

Desalination of Seawater

  • Desalination is the process of removing salt and other impurities from seawater to make it suitable for human consumption and agriculture.
  • There are two main methods of desalination: distillation and reverse osmosis.


  • Distillation involves heating seawater to create steam, which leaves the salt behind. The steam is then condensed to form freshwater.
  • The major drawback is the high energy cost associated with heating the water and condensing the steam.

Reverse Osmosis

  • Reverse osmosis involves forcing seawater through a selectively permeable membrane under high pressure.
  • The membrane allows water molecules to pass through but blocks the passage of salt ions and other impurities.
  • While it consumes less energy than distillation, the high pressure pumps required in this process are still expensive to operate.

Environmental Impact

  • Desalination is not without its environmental concerns. The salt and other impurities removed from the water are typically discharged back into the sea, causing a rise in salinity levels and potentially impacting marine life.
  • Additionally, the process requires a significant amount of energy, contributing to carbon emissions if the energy comes from non-renewable sources.

Future of Desalination

  • Recent advancements in technology aim to make desalination more energy-efficient and environmentally friendly, such as the development of new membrane materials for reverse osmosis.
  • Solar-powered desalination is one potential method to address the energy issue, utilising abundant sunlight in many water-scarce regions to power the process.
  • The challenge is to balance the urgent need for freshwater in many parts of the world with the environmental impact and costs associated with desalination.