separation techniques (newater technology)

Separation Techniques(NEWater technology)

By Mah Kim Chuan, James(1O217)

Term 3 Science ACE

Brief introduction to NEWater

NEWater is…• Treated waste water that is potable and

consumable by humans.• Ideal for industrial uses.• Reclaimed water produced by Singapore's

Public Utilities Board.

History of NEWater

• 1972-Singapore's first water masterplan was drawn up.

• 1974-PUB built a pilot plant. Due to huge costs and unreliability of membranes, idea was delayed to await technology advancements.

• 1998-technolgy advanced, production costs lowered.

• 2000-first NEWater plant completed.

Why NEWater is essential to us?

• Alternative water source to reduce reliance on Malaysia’s imported water.

• Reclaimed water that is mostly used for many commercial purposes, saving other potable water sources for drinking.

• Currently meets 30% of Singapore’s water demands.

Processes in NEWater

• Microfiltration

• Reverse osmosis

• Ultraviolet disinfection

• Through these processes, waste water becomes purified completely into reclaimed water, used for commercial and drinking purposes.

Microfiltration (First Stage)

• Basically, this process is a special type of filtration.

• Unwanted substances, like suspended solids, tiny particles, bacteria and viruses, are filtered out by a membrane.

• Only dissolved salts and organic molecules pass through the membrane.

Microfiltration process

• Basically, the waste water passes through the hollow fibres. Only dissolved salts and organic molecules can pass through completely and enter the water pipe; the unwanted substances are trapped in the hollow fibres.

Reverse Osmosis (Second Stage)

• The second separation technique in the whole process.

• The water passes through tiny pores in a semi-permeable membrane which only allows very small molecules like water molecules to pass through.

• Contaminants, such as viruses and bacteria, are gotten rid of.

Reverse Osmosis Process

• Pressure is applied on the water on one side of the semi-permeable membrane. Only pure water molecules are small enough to pass through the membrane to the other side of the membrane. Larger substances, like bacteria, are unable to pass through. By then, the water is of very high quality.

Ultraviolet Disinfection(Third Stage)

• As a safety measure, the water goes through ultraviolet radiation for disinfection purposes.

• Chemicals may also be added to restore the pH balance of the water.

• The end product would be very pure water of high quality.

Ultraviolet Disinfection Process

• Water molecules bask under ultraviolet radiation for disinfection purposes, to kill any harmful particles such as bacteria or viruses that managed to resist the previous stages. Chemicals are also added to restore the pH balance of the water.

Drawing

The whole process…

Separation Techniques used

• Filtration- filter unwanted substances in the waste water from the water.

• Reverse Osmosis- applies pressure on one side of the membrane to force tiny molecules, like water molecules, to pass through the membrane to the other side of the membrane.

Why NEWater is worldwide acclaimed

• Passed more than 65,000 tests and passed World Health Organisation(WHO) requirements.

The SECRET behind NEWater: RO

• Reverse Osmosis• RO has been used extensively in many other areas:

the production of bottled drinking water and production of ultra-clean water for the wafer fabrication and electronics industry.

• RO is also becoming increasingly popular as one of the technologies used in desalination of seawater for human consumption. It is also used to recycle used water to drinking water on space shuttles and on International Space Stations.

Video of NEWater technologies by PUB

• URL: http://www.youtube.com/watch?v=72QLHKbhQ_s

NEWater Factories in Singapore

• Ulu Pandan• Kranji• Seletar• Bedok• Changi

Summary

• Microfiltration is used to filter unwanted substances, like bacteria and viruses, from the water.

• Reverse Osmosis is used by applying pressure on the water at one side of the membrane, forcing very small molecules, like water molecules, to pass through to the other side.

• Ultraviolet Disinfection is used to kill remaining surviving bacteria to ensure that the water is very pure. Chemicals are then added to restore the pH balance of the water.

Bibliography

• http://www.pub.gov.sg/about/historyfuture/Pages/NEWater.aspx

• http://en.wikipedia.org/wiki/NEWater• http://

www.pub.gov.sg/LongTermWaterPlans/wfall_3rdtapa.html

• http://newatersingapore.blogspot.sg/p/mechanisms-of-newater.html

• http://www.pub.gov.sg/water/newater/newatertech/Pages/default.aspx

Thank you for your kind attention!