What is NEWater? Reclaimed and purified wastewater produced by the Public Utilities Board. Took 30 years to draw up plan. Predecessor plan first draw up in 1972. First NEWater Plant was completed in May 2000.
So How Is NEWater Obtained? Wastewater is collected and then “cleansed” using the following methods: Wastewater treatment Microfiltration Reverse Osmosis Ultra-Violet (UV) Disinfection Water collected after going through the above methods is called NEWater.
Separation Techniques Used The main type of separation technique used in NEWater plants is filtration. Of the 4 “cleansing” methods metioned previously, only Ultra-Violet (UV) Disinfection is not a type of separation technique.
Process of Purification(Treatment Process) Wastewater treatment NEWater Ultra-violet Disinfection Microfiltration Reverse Osmosis
Wastewater Treatment Sand filters
Raw water collected is first filtered using sand filters to trap the suspended solid particles in the sand.
Clear water then runs through the setup.
Microfiltration A filtration process which removes colloidal and suspended particles in a fluid.
Function of Microfiltration units In this case, microfiltration units in the NEWater plant removes the suspended solids, bacteria, protozoa and colloidal particles. The treated used water is passed through hollow tubes or a semi-permeable membrane.
Process of Microfiltration Secondary treated effluents are passed through semi-permeable membranes which only allow certain particles to pass through. Most micro-organisms and waste particles cannot pass through this membrane.
Microfiltration Medium concentration of micro-organims and waste particles Secondary treated effluent Semi-permeable membrane Filtered water Low concentration of micro-organisms and waste particles
Another type of Microfiltration Suspended solid particles Reverse Osmosis Units Water Flow Hollow fibre tubes Filtered water
Another type of Microfiltration Treated used water is passed through hollow fibre tubes which do not allow suspended solid particles to pass through.
Reverse Osmosis Another type of filtration which separates salt particles and other waste particles from fresh water. In the NEWater plant, the Reverse Osmosis units remove viruses, fine colloidal particles, dissolved organics and dissolved salts.
Process of Reverse Osmosis Water which has passed through the microfiltration units will now pass through the reverse osmosis units. The solutes and suspended particles are removed from the water and only pure water can pass through the semi-permeable membrane.
Reverse Osmosis Filtered water Very low concentration of micro-organisms. Polluted water (After microfiltration) Semi-permeable membrane Low concentration of micro-organisms and waste particles
Reverse Osmosis The semi-permeable membrane only allows water particles to pass through. It traps bacteria, suspended solids and protozoa and colloidal particles.
Ultra-Violet (UV) Disinfection Highly effective method used to disinfect water. A sterilisation method used to break down micro-organisms in the water.
Ultra-Violet (UV) Disinfection Not a type of separation technique. Used only to disinfect water so that water is potable.
Bibliography The NEWatertreatement process. (n.d.). Retrieved from http://www.pub.gov.sg/water/newater/newatertech/PublishingImages/newater_process.swf Sand Filter. (n.d.). Retrieved from http://en.wikipedia.org/wiki/Sand_filter Water Treatment Plant. (n.d.). Retrieved from http://www.thewatertreatmentplant.com/microfiltration-system.html PUB LP Newsletter. (n.d.). Retrieved from http://www.pub.gov.sg/general/Documents/2002Q3.pdf MIcrofIltratIon. (n.d.). Retrieved from http://en.wikipedia.org/wiki/Microfiltration