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NEWATER-The process of purifying water. Done by li jiawang (13) 1a1. History. Considered in 1970s but experiment plant was closed down Cost and reliability issues
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NEWATER-The process of purifying water Done by lijiawang (13) 1a1
History Considered in 1970s but experiment plant was closed down Cost and reliability issues Initiated again by PUB in 1998 through a study to determine if NEWATER was a viable source of raw water for Singapore's needs. Found to reliable and able to reduce reliance on Malaysia imported water In 2001, NEWATER began to increase its production for non-potable water
NEWATER Term coined by the PUB It is ultra clean and has passed more than 30000 tests surpassed the requirements for potable water. Aims to provide Singapore with a sustainable and diversified supply of water Expected to meet 40% of Singapore's water needs by 2020.
Production-first barrier First barrier (conventional water treatment process) Coagulation and filtration Coagulation: process of adding iron or aluminium salts to the water The salts containing positive charge neutralizes the negative charge of both dissolved and suspended particles in the water The particles bind together and due to the fact that the particles are now heavier, the settle down in the bottom of the container
First barrier Filtration: slow sand filtration and rapid sand filtration Slow sand filtration: use bacteria to treat water as the bacteria grows and establishes on the top surface of the sand to purify the water by digesting the bacteria as it passes through. Rapid sand filtration: physical method of purifying water
Second barrier Microfiltration: filtering out suspended solids, colloidal particles, disease-causing bacteria, some viruses and protozoan cysts. Membrane pores in microfiltration are 0.1 to 10 micrometers
Third barrier Reverse osmosis: forcing water to go from low pressure to high pressure trough a semi-permeable membrane The membrane allows only water to pass through but not other impurities Examples of such membranes are: our intestine walls and cell membranes
Fourth barrier Ultraviolet disinfection: using ultraviolet radiation to deactivate microorganisms Purely physical The radiation attacks the vital DNA in the microorganisms and destroys the genetic information. Sterilized and killed bacteria is NOT removed from the water.
Further processing Blended with reservoir water The NEWATER is blended with reservoir water so as to regain the lost nutrients during the process of purifying and also to gain more public acceptance.