Desalination

The 4^th national tap that help Singapore increase water supply is to desalinate water through technology. Desalination is a process which removes salt from sea water. The most important process of desalination is the reverse osmosis; it uses a high pressure to force salty water through a semi-permeable membrane. After the water have pass through it will left with purified water and a concentrated salt. Other process is distillation, it is a process whereby the water is boiled and water vapour is collected and condensed into fresh water. Each day the plant can supply up to 500 million liters of water.  

 The advantages is it guarantees that in a drought there is always clean water, improves fish habitat, desalination plants are the size of a warehouse and will be situated in an area close to other industrial facilities and away from large residential areas. The most important advantage is that we do not need to depend on other countries or weather to supply water.

However, its disadvantage is that it uses up a lot of energy so it is costly. The critics also believe that it emits green house gases which will be harmful to the environment. Also people might not be able to get use to the taste of the water as most of the nutrients are remove from the water.

Photo Source: http://www.usbr.gov/lc/yuma/facilities/images/rodiagram.png                                                        Video Source: http://www.youtube.com/watch?v=u54T7hbR_R4