Seawater Desalination and Water Supply Reliability

2. Chenab College of EngineeringChenab College of Engineering
& Technology GRW& Technology GRW

3. Seawater Desalination andSeawater Desalination and
Water Supply ReliabilityWater Supply Reliability

4. Submitted To: Engr. M Bilal
Group Members:
Usman Ali 2014-uet-ccet-mech-05
M. Ahmad 2014-uet-ccet-mech-09
H. Zahid Ali 2014-uet-ccet-
mech-14
Qamar Abbas 2014-uet-ccet-mech-15

5. OutlineOutline
• M. AhmadM. Ahmad IntroductionIntroduction
• Qamar AbbasQamar Abbas MFS & ReverseMFS & Reverse
Osmoses DesalinationOsmoses Desalination
• Usman AliUsman Ali Freezing & GeothermalFreezing & Geothermal
DesalinationDesalination
• H.Zahid AliH.Zahid Ali Solar DesalinationSolar Desalination

6. What is Desalination?What is Desalination?
Desalination is a process that removes minerals fromDesalination is a process that removes minerals from
saline water.saline water.
More generally,More generally, desalination refers to the removal ofdesalination refers to the removal of
salts and minerals from a target substance, as insalts and minerals from a target substance, as in
soil desalination, which is an issue for agriculture.soil desalination, which is an issue for agriculture.
Saltwater is desalinated to produce water suitable forSaltwater is desalinated to produce water suitable for
human consumption or irrigation.human consumption or irrigation.
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7. HistoryHistory
• Clean drinking water is so widely availableClean drinking water is so widely available
today that many people take it for granted. Intoday that many people take it for granted. In
actuality, human beings have taken extensiveactuality, human beings have taken extensive
measures throughout history to producemeasures throughout history to produce
clean drinking water.clean drinking water.
• In the ancient times, people determined theIn the ancient times, people determined the
purity of water by taste, and this method haspurity of water by taste, and this method has
been found to be incorrect later onbeen found to be incorrect later on
• Old water treatment methods include theOld water treatment methods include the
boiling of water over fire, heating of waterboiling of water over fire, heating of water
under the sun, dipping of heated iron intounder the sun, dipping of heated iron into
water, filtration through gravel and sand.water, filtration through gravel and sand.
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8. Why Desalination?Why Desalination?
• 75% of the Earth’s surface75% of the Earth’s surface
is covered by wateris covered by water
• 97.5% of that water is oceans97.5% of that water is oceans
• Only 1% is available forOnly 1% is available for
drinkingdrinking
• 80 countries suffered from80 countries suffered from
waterwater
scarcity by the mid-1990sscarcity by the mid-1990s
• 1.5 billion people lack access1.5 billion people lack access
to drinking waterto drinking water
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9. Desalination TechniquesDesalination Techniques
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10. Multi Stage FlashMulti Stage Flash
desalinationdesalination
• Multi-stage flash distillation (MSF) is a
water desalination process that distills sea
water by flashing a portion of the water
into steam in multiple stages of what are
essentially countercurrent heat
exchangers. Multi-stage flash distillation
plants produce about 60% of all
desalinated water in the world

11. Multi Stage FlashMulti Stage Flash
desalinationdesalination
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12. Revers OsmosisRevers Osmosis
• Reverse osmosis (RO) is a water
purification technology that uses a
semipermeable membrane to remove
ions, molecules, and larger particles from
drinking water. In reverse osmosis, an
applied pressure is used to overcome
osmotic pressure.
• The largest and most important
application of reverse osmosis is the
separation of pure water from seawater

13. EfEffectiveness of Reverse Osmosisfectiveness of Reverse Osmosis

14. Revers OsmosisRevers Osmosis
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15. Freezing desalinationFreezing desalination
• Freezing desalination process uses
freezing to remove fresh water from frozen
seawater.
• Seawater's freezing point is lower than that
of pure water and its boiling point is higher.
• It is easier to float objects in seawater than
in fresh water. Many humans can “float” in
seawater but not fresh water. Floating
refers to having a substance rise to the top
of another substance.

16. Freezing desalinationFreezing desalination
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17. Geothermal desalinationGeothermal desalination
• Geothermal desalination is a process
under development for the production of
fresh water using heat energy. Claimed
benefits of this method of desalination are
that it requires less maintenance than
reverse osmosis membranes and that the
primary energy input is from geothermal
heat, which is a low-environmental-impact
source of energy.

18. Geothermal desalinationGeothermal desalination
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19. Solar desalinationSolar desalination
• Solar desalination is a technique to
desalinate water using solar energy.
Types:_
Solar humidification–
dehumidification method (HDH)
Multiple-effect humidification (MEH)

20. Solar humidification–dehumidification
method (HDH)
• The solar humidification–dehumidification
method (HDH) is a thermal water
desalination method. It is based on
evaporation of sea water or brackish water
and consecutive condensation of the
generated humid air, mostly at ambient
pressure

21. Solar desalinationSolar desalination

22. Multiple-effect humidification
(MEH)
• Multiple-effect humidification (MEH) is a
method used for thermal desalination of
sea water. It uses multiple evaporation–
condensation cycles at separate
temperature levels to minimize the total
energy consumption of solar
humidification processes.

23. Multiple-effect humidification
(MEH)

24. Factors Increase the waterFactors Increase the water
consumption areconsumption are
• Growing of populationGrowing of population
• Growing of industryGrowing of industry
• Agriculture/Irrigation needsAgriculture/Irrigation needs

25. Thank youThank you