Desalinization - A solution for water crisis

Source: The Indian Express

Why in news?

National Institute of Ocean Technology is about to set up green, self-powered desalination plant in Lakshadweep

What is desalination?

1. Desalination is the process of removing salt from sea water so that it can be used for drinking, or for watering crops.
2. Desalination uses thermal distillation or a reverse osmosis membrane to separate salt from the sea.
3. Reverse osmosis involves applying external pressure to force solvents through a membrane from a high-solute concentration portion to a low-solute concentration area.

What is the status of desalination plants in India?

• The first desalination plant in India is Minjur in Tamil Nadu state in the year 2010.
• The second plant was inaugurated at Nemmeli in Tamil Nadu.
• The second-largest desalination plant situated in Jamnagar of Gujarat
• National Institute of Ocean Technology to set up green, self-powered desalination plant in Lakshadweep.

What is Low Temperature Thermal Desalination (LTTD)?

The LTTD is a process under which the warm surface seawater is flash evaporated at low pressure and the vapour is condensed with cold deep seawater.

What are the advantages of desalination?

• The cost of desalination plants  have decreased tremendously
• The desalination plants could ensure water security throughout the year.
•  Use of solar energy in desalination plants can mitigate climate change.
• The quality of the water is not compromised
• The source is unlimited
• Helps preserve current freshwater supplies

What are the disadvantages of desalination?

1. Emits more greenhouse gases
2. High-salinity  brine effluents affects  the marine  ecosystem
3. May lead to  hypoxia
4. Exacerbate climate change if renewable energy is not used as source of power
5. Chemical compounds involved in pre-treatment process can be toxic to marine organisms

What is the need of the hour?

• To use renewable energy to power desalination plants
• Safe Disposal of hypersaline wastewater or brine away from the marine organisms

Quick facts

About 2.2 billion people in the world are deprived of access to safe water.

Nearly three out of four natural disasters are linked to water, and a quarter of the planet lives without safely managed water services or clean drinking water.

The World Water Day (WWD) has been observed on March 22 every year since 1993

While around 70% of Earth’s surface is covered with water, less than 1% per cent is actually drinkable.