desalination of water chemistry year 8.pptx

Chemistry year 8

1. DESALINATION OF WATER

2. 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.

3. Salinity Type 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

4. 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

5. Why desalination?

6. Natural desalination Major Stages: 1.Evaporation 2. Condensation 3. Precipitation 4. Collection

7. Principal methods used for desalination Distillation(Evaporation) Electro dialysis Freezing Reverse osmosis

8. Distillation d Salt water is heated in one container to make the water evaporate, leaving the salt behind. This will make steam. Steam travels through the condenser. When it colds, the water vapour will turn into a liquid back and drips into the beaker. The salt will remian in the flask

9. Freezing It is based on the principle that water excludes salts when it crystallizes to ice.

10. Reverse osmosis

11. Wonthaggi Desalination Plant, Victoria, Australia Aerial view of the IDE desalination plant in Hadera,israel .

12. Positives of desalination S afety 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, need huge amount of electticity. Water Quality Problem (not contain dissolved calcium compounds) completely pure (some people do not like the taste) Seawater desalination may affect the sustainable growth of coastal area. Negatives of desalination

13. Future scope Desalination 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.

14. The end Save water; Save life; Secure future.