Singapore is also promoting its innovative achievements to the world. This June, the Singapore International Water Week will be held again, with the theme "Sustainable Cities: Clean and Affordable Water."
Every drop of used water is a new water resource
If someone told you that this bottle of water, which looks no different from other drinking water, came from the sewage pipes in your home but has been purified, would you dare to drink it?
"This NEWater is mainly for everyone to try the quality of new water. Our NEWater is primarily supplied to industrial users, and this industrial water is even cleaner than drinking water; tap water is not clean enough for these enterprises," explained Tan Yok Ren, Director of the Water Supply Department at Singapore's Public Utilities Board (PUB).
Once the Changi NEWater Plant, Singapore's largest NEWater facility, is completed this May, the total production of NEWater will meet 30% of Singapore's total water demand by 2011 (approximately 530,000 cubic meters per day).
NEWater is mainly transported directly to enterprises as non-potable water through special pipelines, with a portion injected into reservoirs as an indirect source of drinking water.
Before NEWater, about half of Singapore's tap water supply was provided to industrial and commercial enterprises for non-potable use. A wafer fabrication plant requires 10,000 cubic meters of water per day. As a major global oil refining hub, Singapore also has a massive water demand. NEWater is produced through reverse osmosis membranes; it is pure water, and its quality meets the requirements of these enterprises.
NEWater is not supplied directly to residents primarily due to economic considerations, as residential water demand is relatively low.
The current practice is to inject NEWater into reservoirs to mix with rainwater, which is then purified by water treatment plants and supplied as tap water. This approach has another benefit: during droughts, the water level in reservoirs can be maintained by increasing NEWater production and injecting it into the reservoirs. Previously, during droughts, Singapore had to rely on the mercy of the weather.
The source of NEWater is treated used water (in Singapore, sewage and wastewater are referred to as "used water"). Previously, used water was discharged into the sea and not recycled. The completion of Singapore's Deep Tunnel Sewerage System (DTSS) ensures the sustainability of recycling used water; therefore, this system is also known as the "superhighway" for Singapore's used water. The completion of the sewerage system also led to a reduction in the number of sewage treatment plants in Singapore, from six to the current four, replaced by the mega-sewage treatment plant, the Changi Water Reclamation Plant.
The Changi Water Reclamation Plant has a daily sewage treatment capacity of 800,000 tons, with used water transported from various locations to the plant for purification via the deep tunnel through gravity. The purified sewage is then supplied to the NEWater plant as a source. The Changi NEWater Plant is located near the Changi Water Reclamation Plant. It is Singapore's fifth NEWater plant and is capable of producing 250,000 tons of NEWater per day.
"Our philosophy is that for every drop of water resource you use, if you recover every single drop, you have that much water resource," said Tan Yok Ren.
Reservoirs built in the heart of the city
With a gentle breeze blowing and the air carrying a faint scent of the sea, bursts of laughter can be heard from time to time. The Marina Barrage quietly watches the people playing around it.
The Marina Reservoir is a reservoir located in the city center. Tan Yok Ren explained, "Few other countries have such a mechanism. In Singapore, basically all developed land is a water catchment area. Singapore's land area is too small, and there are no conditions to concentrate water sources in forest areas or undeveloped regions."
The completion of the Marina Barrage realized Singapore's fifteenth reservoir—the Marina Reservoir. Currently, half of Singapore's land is already a catchment area. It is expected that by 2011, the catchment area will reach two-thirds of the country's land area. Before 2000, Singapore's water resources mainly relied on external supply from Malaysia and domestic catchment areas.
The catchment area formed by the Marina Barrage is Singapore's fourth-generation catchment area. The completion of the fourth-generation catchment area means that whatever is under the people's feet—whether it is a place for living, working, or leisure—basically all rainwater that falls will be collected as part of Singapore's water supply. The first-generation catchment area in Singapore was the traditional method adopted by many countries, located in Singapore's forest reserves and undeveloped areas, but the area was very small. The second-generation catchment area expanded outward from the first. During urban development planning, it was not only planned as a construction zone but also as a catchment area. The third-generation catchment area was built in residential and industrial areas, collecting rainwater into storm water collection ponds, and then pumping the water to larger reservoirs for collection.
The construction of the Marina Barrage was based on two prerequisites: first, a breakthrough in membrane technology, as advanced membrane technology allows for the purification of water supply from highly urbanized catchment areas, enabling the purification of sewage and used water into drinking water; second, the ability to keep cities and rivers clean. As early as 1977, the rivers in Singapore's entire urban area were basically polluted. After experiencing the "Ten-Year Clean River Plan" from 1977 to 1987, the river pollution problem was basically solved. After the completion of the Clean River Plan in 1987, former Prime Minister Lee Kuan Yew proposed a concept: "Within twenty years, there may be breakthroughs in filtration and anti-pollution technology, and by then we can build a barrage in the Marina to form a large freshwater lake."
The Marina Barrage project was implemented in 2002 and fully completed in 2008.
In addition to increasing Singapore's drinking water supply, the Marina Barrage also serves the functions of flood prevention and providing a new attraction for citizens' leisure activities.
Institutional design behind innovation
The Public Utilities Board (PUB) of Singapore is a government agency that operates like a private enterprise. Its responsibility is to manage all water-related work in the country, including drinking water supply, used water treatment, and seawater management. This agency was born in 2001 by integrating the Sewerage Department under the former Ministry of Trade and Industry and the Sewerage and Seawater Departments under the Ministry of the Environment and Water Resources into a unified water management agency.
Singapore's electricity and gas supplies were privatized in the 1990s. The unified management of Singapore's water sector has been in place for nearly a decade. The entire water cycle is basically managed by the Public Utilities Board.
The initial research and development of NEWater were the responsibility of the Public Utilities Board, and the entire operating cost is covered by the water fees it collects. Currently, of Singapore's 5 NEWater plants, 3 are operated by the Public Utilities Board, and the 2 largest are privately operated.
The Public Utilities Board uses the 25-year water supply volume for Singapore as the contract target, and private enterprises bid based on the price per ton of water to determine the winning enterprise. During the plant construction process, the Public Utilities Board sets basic technical standards at each step while also allowing enterprises to make adjustments based on those basic standards.
The cost ratio of traditional rainwater collection, NEWater, and desalinated seawater is roughly 1:2:4. Because the cost of laying pipeline networks is relatively high, NEWater is mainly supplied centrally, primarily providing for industrial users in Singapore's electronics, chemical, and pharmaceutical industrial zones.
Desalinated seawater also adopts roughly the same model. Hyflux (Singspring) and the Public Utilities Board reached a 20-year DBOO (Design, Build, Own, Operate) cooperation agreement to sell water to the Public Utilities Board. Currently, it provides 140,000 tons of tap water per day.
The two new water sources developed in 2002 now provide 40% of Singapore's water usage. Desalinated seawater accounts for 10% of the water supply, and NEWater accounts for 30%.
Tan Yok Ren said, "We focus more on solutions than on highly academic scientific research. We hope to share with the international community, such as the practice of urban rainwater collection and our achievements in NEWater, among other experiences."
