The Defence Research & Development Organisation (DRDO), under the Aatmanirbhar Bharat initiative, has successfully developed a high-pressure, nanoporous, multilayered polymeric membrane for seawater desalination.

Developing Agency:

• The technology was developed by the Defence Materials Stores Research & Development Establishment (DMSRDE), Kanpur, a DRDO laboratory.
• It addresses the Indian Coast Guard's (ICG) operational needs aboard Offshore Patrol Vessels (OPVs), especially to counter instability caused by chloride ions in saline water.

Salient Features of the Technology:

• Indigenous development completed in a record time of 8 months.
• Successfully tested in existing desalination plants aboard ICG vessels.
• Undergoing 500-hour operational testing before final clearance by ICG.
• Can be adapted for use in coastal areas for civilian desalination purposes as well.

Strategic Significance:

• Enhances onboard freshwater self-reliance for maritime security forces.
• Reduces dependency on imported technologies.
• Contributes to India’s self-reliance in critical defence and water technologies.

Desalination Technology: Key Concepts

What is Desalination?

Desalination is the process of removing dissolved salts and minerals from seawater or brackish water to produce potable or industrial-grade water.

Main Technologies Used:

• Reverse Osmosis (RO):
  • Pressure-driven membrane filtration.
  • Uses semi-permeable membranes to separate salts from water.
• Thermal Desalination:Involves evaporation followed by condensation to obtain fresh water.

Working of RO Desalination:

• In osmosis, water naturally moves from low solute to high solute concentration across a membrane.
• In reverse osmosis, external pressure is applied to force water from high solute (saline) to low solute (freshwater) side.
• RO membranes allow only water molecules to pass, filtering out salts and impurities.
• Seawater with ~35,000 ppm Total Dissolved Solids (TDS) is reduced to 200–500 ppm, making it drinkable.