sea water desalination by reverse osmosis

SEA WATER DESALINATION BY REVERSE OSMOSIS

PRESENTED BY:AYUSH SHARMA BHATTARAI

SUNGKYUNKWAN UNIVERSITY

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Outline of the Presentation

1. Introduction2. Reverse Osmosis3. Reverse Osmosis Process4. Advantages and Disadvantages of Reverse Osmosis5. Conclusion6. References

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Sea Water• water from a sea or ocean• Contains a salinity of about 3.5% (i.e.

35 g/kg of dissolved salt• More denser than fresh water and pure

water• Freezing point decreases than fresh

water(−2 °C)• pH ranges between 7.5 and 8.4

INTRODUCTION

Fig: Sea water

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What is Desalination?

• Desalination is the process of removing of dissolved salts from sea water.

• desalinated water is suitable for human consumption or irrigation.

• 1% of worlds population is dependent on desalinated water

• By 2025, UN expects 14% water scarcity

• Great future

Fig: Desalination

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Methods Of Desalination

1. Multi-stage Flash (MSF)2. Multi-Effect Distillation(MED)3. Mechanical Vapor Compression(MVC)4. Reverse Osmosis

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Fig: Multi-stage Flash (MSF) Fig: Multi-Effect Distillation(MED) Fig: Mechanical Vapor Compression(MVC)

Methods Of Desalination contd.

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Reverse Osmosis (RO)

• a water purification technology that uses a semipermeable membrane. • Also called membrane desalination process.• Saltwater is forced through membrane sheets at

high pressures.• Pressure applied depends upon molar

concentration• Membrane sheets are designed to catch salt

ions.Fig: Osmotic and Reverse Osmotic flow

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Reverse Osmosis contd.

• The membranes used have a dense layer in the polymer matrix• the membrane is designed to allow only water to pass

through this dense layer, while preventing the passage of solutes (such as salt ions). • This process requires that a high pressure be exerted on

the high concentration side of the membrane • Pressure of 2–17 bar (30–250 psi) for fresh and brackish

water, and 40–82 bar (600–1200 psi) for seawater, which has around 27 bar (390 psi) natural osmotic pressure that must be overcome. Fig: Reverse Osmosis

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General Process of Reverse Osmosis

Fig: Reverse osmosis process

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Water Filter Process By Reverse Osmosis

Fig: Reverse Osmosis System with Basic Components

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Reverse Osmosis Desalination Plants in the World

Fig: Reverse osmosis desalination plant in Barcelona, Spain

Fig: Ras Al Khair Desalination Plant, Saudi Arabia

Fig: Doosan Heavy Industries & Construction: Reverse Osmosis, Dubai

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Reverse Osmosis Desalination

Advantages:• Improves taste, odor and appearance.• Highly effective purification process• Consumes no energy• Very convenient• Flushes away pollutants, does not collect them• Easy to clean• Environment friendly• Low production cost - gives you water of a guaranteed

quality for pennies per gallon

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Reverse Osmosis

Disadvantages: • It is a slow process and also wastes a large portion

of the water that runs through the system• High capital and operating cost• Membranes are prone to fouling • not applicable for concentrated solutions due to

high pressure requirement• High level of pretreatment is required in some cases• RO removes minerals and ions that provide taste to

the water and electrolytes important for human health

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Conclusion

• RO is an effective technology for seawater desalination• Proper pretreatment and monitoring is required• Has great future

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References1. Glater, J. (1998). "The early history of reverse osmosis membrane

development".Desalination 117: 297–309. doi:10.1016/S0011-9164(98)00122-2.2. Lachish, Uri. "Optimizing the Efficiency of Reverse Osmosis Seawater Desalination".3. "Reverse Osmosis Water Filters". Water Softener Center. Retrieved 2 April 2016.4. Grabowski, Andrej (2010). Electromembrane

desalination processes for production of low conductivity water. Berlin 3832527141. Retrieved 2 April 2016. : Logos-Verl. ISBN

5. "Reverse Osmosis Water Filters". Water Softener Center. Retrieved 2 April 2016.6. Desalination Plant Seawater Reverse Osmosis (SWRO) Plant. Water-technology.net

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Thank You