Whether for work or vacation, I have traveled to Asia on several occasions and one recommendation has always followed me: “always drink bottled water”, even for tasks like brushing your teeth, it is better not to risk it and rinse your mouth with water that you know is safe. The recommendation spreads to most of East and South Asia, with destinations such as Thailand, Vietnam, China and India. However, a little over a week ago I visited Singapore and there was something that fascinated me: it’s not just forgetting to always carry a bottle of water, it’s that there wasn’t even one in the hotel room. Instead, a message recommended drinking tap water because it was of exceptional quality.
That a country has quality water is not something miraculous, but Singapore is an anomaly in itself: it rains a lot, but it barely has land, so it lacks large aquifers or large rivers. In fact, for decades it depended on water imported from Malaysia (still doing it). However, they have managed to build one of the most advanced and reliable water treatment systems in the world thanks to the engineering and public policy behind it.
The four national taps. In 2001 the public agency Public Utilities Board (PUB) assumed full control of the water cycle with a unified vision: from rainwater to the water that falls down the drain, achieving a snapshot of the whole, available and necessary resources.
Singapore’s maxim with water is divide and conquer. Thus, it has four different water sources, the Four National Taps managed by the PUB: water from local basins, water imported from Malaysia, reused water and desalinated water. Taking into account that Singapore has had its ups and downs with Malaysia, the other three taps have been gaining importance.
Marina Barrage, Singapore’s 15th reservoir to store water. Bob Tan
Why is it important. In Southeast Asia, water pollution from industrial waste, agrochemicals and a heterogeneous and deficient sewage network means that the norm is to use bottled water. We have already seen that Singapore lacks the land to achieve water self-sufficiency and depending on a third party for something as basic and essential as water is a dangerous alternative. In this scenario, NEWater stands as the most strategic tap: self-generated water without depending on rain, the terrain or the neighbors. Although with quite a bit of small print.
The local watershed. Through a network of drains, canals and rivers, rainwater is collected and channeled through its 7,000 kilometers of pipes to its 17 reservoirs before treating it for consumption. This collection takes place in two thirds of Singapore’s territory. From here, the water follows a conventional purification system. It is the least innovative route, but it is solid, functional and growing: the construction of the eighteenth reservoir is already planned on the land that Singapore is reclaiming from the sea, Long Island.
Water imported from Malaysia. This is the most vulnerable tap and therefore the most susceptible to being eliminated (for now, minimizing as much as the rest of the taps can). He first agreement between Singapore and Malaysia dates back to 1927 and laid the foundation for water supply and land leasing on Gunung Pulai, but is no longer in force.
This was followed by three other agreements signed in 1961, 1962 and 1990. Initially this source provided half of Singapore’s demand, but as explains the National Library and National Archives of Singaporefollowing the expiration of the 1961 agreement in 2011, the government aims to be self-sufficient by 2061, when the 1962 and 1990 agreements end.
Sewage. Is called NEWateris capable of covering 40% of the total demand of the country and from wastewater it is capable of achieving drinking water of superior quality to standards of the WHO. They tried it before, in 1974, but the project failed due to costs and technical problems. The current sewer system cost 10 billion dollars and is designed to last 100 years.
It all starts underground: the sanitation system DTSS It collects all the urban wastewater through a 206-kilometer network and takes it by gravity (without the need for pumping) to the four recovery plants located in Ulu Padan, Kranki and Changi (there are two there). There they use membrane bioreactor, reverse osmosis and ultraviolet disinfection technologies. They currently have a global recovery rate of 90% and a capacity of 227,300 cubic meters per day.
NEWater operation diagram. Data. NEWater with Gemini translation
Seawater desalination. Singapore It has five desalination plants and all of them use reverse osmosis as the main treatment, although with different pretreatment combinations. Desalination is a well-known technique in water engineering, but little applied for one reason: costs. So to optimize the energy process, among the PUB’s main R&D objectives is to reduce energy consumption to less than 2 kWh per cubic meter.
The first was SingSpring and is capable to produce 136,380 cubic meters of water per day, covering around 7% of the country’s water needs. The Tuas plant won the “Oscar” of salinization plants in 2019 thanks to an advanced pretreatment system that combines dissolved air flotation and ultrafiltration to mitigate membrane fouling. Keppel Marina East has an adapted dual system that works for both seawater and freshwater.
Yes, but. From a technical point of view, Singapore’s water infrastructure is brilliant, but it is not without its problems. The first is energy: desalination consume 3.5 kWh per thousand liters of treated water, much more than 0.7 kWh NEWater Faucet. Desalination has a high environmental and economic cost and is highly dependent on electricity. Spoiler: about 95% of Singapore’s electricity is generated from imported natural gas.
On the other hand, drinking water that comes from the sewer, despite its quality, generates a certain social rejection, which is why the majority is destined for industry, where such pure water is ideal for the manufacture of semiconductors. On the other hand, faced with a growing demand for water, the challenge for the future is scalability to maintain its reliability based on an impeccable sanitation infrastructure.
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Cover | Wikimedia and Anthony Lim
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