DESALINATION OF WATER

PRESENTED BY,

V.Amsaveni.

WHAT IS DESALINATION?

Desalination is the process of removing salts and other minerals from the saline water to render it suitable for drinking, irrigation, or industrial uses.

SalinityType of saline water

Salinity value(ppm)

Fresh water <1000

Slightly saline water

1000-3000

Moderately saline water

3000-10,000

Highly saline water 10,000-35,000

• Water, water, everywhere,And all the boards did shrink. Water, water everywhere,Nor any drop to drink.- Samuel Taylor Coleridge (1772-1834), "The Rime of the Ancient Mariner" 1798

Why desalination?

Natural desalination

Major Stages:1.Evaporation2. Condensation3. Precipitation4. Collection

Principal methods used for desalination

• Distillation(Evaporation)• Electro dialysis• Freezing• Reverse osmosis

Distillation

dSalt water is heated in one container to make the water evaporate, leaving the salt behind. The desalinated vapor is then condensed to form water in a separate container. Although long known, it has found limited applications in water supply because of the fuel costs involved in converting salt water to vapor is very high.

Electro dialysisElectrodialysis reversal utilizes a membrane, like that in reverse osmosis, but sends an electric charge through the solution to draw metal ions to the positive plate on one side, and other ions (like salt) to the negative plate on the other. s

FreezingIt is based on the principle that water excludes salts when it crystallizes to ice.

Reverse osmosis

Wonthaggi Desalination Plant, Victoria, Australia

Aerial view of the IDE desalination plant in Hadera,israel.

Positives of desalination• Safety water• Water scarcity can be easily handled.• Availability of Water in Areas of Drought• Alternative Source of

Water• Production of a High

Yield of Water

•Higher Price•Water Quality Problem•Greenhouse Gas Emission•Seawater desalination may affect the sustainable growth of coastal area.

Negatives of desalination

Future scopeDesalination is process primarily done in developed countries with enough money and resources. If technology continues to produce new methods and better solutions to the issues that exist today, there would be a whole new water resource for more and more countries that are facing drought, competition for water, and overpopulation.

The end

Save water;Save life;Secure future.