DESALINATION OF SEAWATER BY REVERSE OSMOSIS

Presented by Valeri Aristide RAZAFIMANANTSOA

(History & Cost)

OUTLINE

Why this subject?

History

Methods used in desalinationCost

Why this subject?

WHY THIS SUBJECT ?

1750 : 791 millions 2009 : 6.9 billion

?

WHY THIS SUBJECT ? (CONT.)

Oceans

Ice

FW

Wv

WORLD’S WATER SUPPLY

WHY THIS SUBJECT ? (CONT.)

UNESCO's World Water Development Report (WWDR, 2003) from its World Water Assessment Program indicates that, in the next 20 years, the quantity of water available to everyone is predicted to decrease by 30 percent.

40 percent of the world's inhabitants currently have insufficient fresh water for minimal hygiene.

History

HISTORY OF DESALINATION

Desalination process is not a new concept.

During the 1700s water desalination plants were developed in the UK, Europe and the US and simple desalination systems became standard equipment on ships during the 1800s.

The first large scale desalination operations were undertaken in the Middle East following World War II.

The popularity of water desalination increased in the 1960s with the reliability of the reverse osmosis (RO) membrane.

HISTORY OF DESALINATION (CONT.)

Today there are over 14,000 desalination plants in operation around the globe (60% of which are in the Middle East and 12% in the United States)

Ashkelon Plant, Israel

Methods used in desalination

Ion exchangeDistillation Membrane processes

Freezing

METHODS USED IN DESALINATION

Geothermal desalinisation

Seawater greenhouse

Reverse osmosis plants are the most common type, but multi-stage flash distillation plants produce over 85 PERCENT of all desalinated water in the world.

Cost

37

44

4

75

3

Percent distribution of cost factors

fixed costelectric powerlabormaintenancemembrane replacementconsumables

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