The importance of potable water cannot be understated; not only do humans require it to survive and thrive, but industries and other functions integral to society and the upkeep of a stable economy necessitate a clean, stable, and reliable supply of water. A lack of safe drinking water can lead to widespread disease in a community and can reduce the potential of a community developing its economy (World Health Organisation, 2019). Desalination is a process used to remove the mineral components of saline water. The most common form of desalination used on an industrial scale is reverse osmosis, as the process is highly scalable, and produces pure potable water well in line with the World Health Organization's guidelines on potable water. The process works by pressurising water through a special membrane, to remove large molecules and minerals, and generally only requires electricity and several chemicals to function. (Lasky, 2019).
The history of alternative water sources has an interesting history in Singapore. Since Singapore’s independence in 1965, the country has developed 14 new reservoirs to collect water, and has increased the land area from which it is possible to collect water to more than 67 percent. Singapore is now the leading country when it comes to producing reused water, with NEWater covering up to 40% and desalination producing up to 25% of daily demand. Singapore invests heavily in the research and development of water and water systems, and has one of the most efficient water utilities in the world (Tortajada, 2018). This supremacy in the water technology field was not without reason, and was born out of an extreme necessity for water. Singapore has little ability to naturally gain fresh water, and therefore originally relied almost entirely on Malaysia for fresh water. However, due to the nearing expiry of the water bill that allows Singapore fresh water at such a cheap price, the country has been forced to invest heavily in alternative ways of producing water in such a small amount of space. One method of producing fresh water that Singapore has made part of its long term water plan is desalination.
The research Singapore has put into desalination has allowed reverse osmosis technology to become as reliable and efficient as possible. In addition, the desalination plants are public-private partnership projects, which permit people to tap on and grow private sector information to reap efficiencies in the cost and the technology. Singapore often monitors the quality of sea water around the desalination plants to ensure the impact on the environment is minimised. Any water that enters the sea from the desalination plant must go through a diffuser which dilutes the waste with surrounding sea water.
Despite the efficiency and usefulness desalination has brought to the Singaporean water supply, the technology is not applicable or effective in every location, and the needs of desalination plants are very specific. Firstly, desalination is already not readily available to many countries, as it is an extremely costly water supply method, with large upfront investments and many long term payments to keep it up and running, and is consistently viewed as the most expensive or one of the most expensive water supply methods. For this reason, desalination is usually only considered to be a viable alternative for the water supply system when the alternatives in these locations are also of a high cost, or where the risks of an interruption in water supply are great.
In terms of the supply of desalinated water to consumers, desalination plants require very specific locations to become an effective portion of a water supply, and there are several main factors that decide the location of a potential desalination plant. Firstly, and most apparently, a desalination plant must be near a large source of seawater. In addition, because water is a very difficult resource to transport, especially in the large quantities that are needed, the desalination plant should be located in the vicinity of the area that it is going to serve (The World Bank, 2019). Fried also claims that besides the already established high price and energy consumption of the technology, the fresh water that it does produce may not be entirely pure enough, may contain chemicals used in the purification process, and the entire process may pollute waterways (2009). Currently, Singapore’s water supply is made up of up to 30% desalinated water, and is heavily reliant on its desalination plants. When these chemicals are dumped into the ocean, it may pose a threat to the environment, and especially fishes in the surrounding water. On top of this, estimates say that the intake mechanisms of desalination plants have killed as many as 3.4 billion fish. Lastly, some experts claim that desalination contributes more to global warming than most other forms of water collection and purification, due to the large amount of energy required to remove the salt from such massive amounts of water (Fried, 2009).
Fried, K. (2009, April 2). Ocean desalination no solution to water shortages. Food & Water Watch. https://www.foodandwaterwatch.org/news/ocean-desalination-no-solution-water-shortages
Lasky, J. (2019). Reverse osmosis (RO). In Salem Press Encyclopedia of Science.
Tortajada, C. (2018, July 2). Commentary: Singapore’s water story underscores the value of
preparedness. CNA. https://www.channelnewsasia.com/news/commentary/singapore-water-story-underscores-the-value-of-preparedness-10474114
The World Bank. (2019). The role of desalination in an increasingly water-scarce world.
World Health Organisation. (2019, June 14). Drinking water. WHO | World Health Organization.