Singapore’s Public Utilities Board (PUB) is one of the few water agencies in the world with a balanced supply of water, supported by long term plans to keep it that way. Its 50 year plans take into account an increased population, potential drought, potential flooding, and a potential rise in ocean levels. The PUB is already engineering new water supply technologies that help counter these dangers and that can be utilised worldwide.
Singapore’s water comes from four main sources called the “Four National Taps”: Local rainwater catchments, imported water, NEWater (recycled), and desalination. These sources of supply are part of an integrated program that has three main pillars:
- To capture every drop of rain that falls on Singapore,
- To collect every drop of used water,
- To recycle every drop of water more than once.
Leslie Swanson, Organizational Development Consultant, lived in Singapore for 20 years while working at MSD Pharma. She said, “I watched as Singapore transformed itself into becoming a leader in water sustainability.”
Having access to water has been a recent luxury for most Singaporeans. Within the last 50 years, they have gone from bathing with a bucket and scoop to having running water 24/7. Now total water demand hovers around 400 million gallons of water per day (mgd), with 45% of that used for domestic consumption and the rest for non-domestic use.
Of that demand, reclaimed water supplies 30%, desalination provides 25%, and the rest is split between 17 local reservoirs (i.e. rainwater) and imported water. PUB is currently working with local communities to lower demand through conservation and, during the next 50 years, will focus on implementing new technologies to run each of its four taps more efficiently.
Tap 1 – Rainwater Catchment
PUB collects rainwater in 17 reservoirs around the island – two thirds of the island being used for water catchment. Many of Singapore’s reservoirs are located inside the city itself, including drainage from some of its oldest, densest population areas (e.g. the Central Business District). Using specialised filtering membranes, PUB cleans all of its collected water to World Health Organization (WHO) drinking standards.
According to PUB’s long term plan Our Water, Our Future, “Singapore is probably the only city in the world where urban stormwater harvesting is carried out on such a large scale.”
Tap 2 – Imported Water
In 1961 Singapore negotiated an agreement with the Johor State Government to import up to 250 mgd from the Johor River until 2061. Johor is the southernmost state on the Malaysian Peninsula, linked to the island of Singapore by two constructions – a 1,920 metre twin-deck three lane roadway and an older 1,056 metre causeway that includes a road, rail line, and water pipe. PUB does not aim to increase this amount of water in future, but will supply Singapore’s population growth via the next two taps.
Tap 3 – NEWater
Singapore considers NEWater to be the pillar of its water sustainability program. The government introduced this high-grade reclaimed water project in 2003, wherein used water is purified using anaerobic micro-organisms, micro-filtration, reverse osmosis, and ultraviolet disinfection techniques. (The biogas produced is collected for power generation.) Before being released for public use, NEWater’s ultra-clean reclaimed water passed more than 130,000 scientific tests for quality.
Singapore uses NEWater mostly for air conditioning systems and industrial procedures in wafer fabrication plants, industrial estates, and commercial buildings. Excess NEWater is sent to the local reservoirs for use during the dry season. This water source meets 30% of current demand and aims for 55% by 2060.
To support this program, PUB built a Deep Tunnel Sewerage System that centralises sewage collection and treatment, and frees up surface land for other uses. PUB is now experimenting with locating recycling and desalination plants together, so they can use the concentrated brine discards from each plant to generate osmotic power for electricity.
As part of a team building day, Ms Swanson accompanied MSD’s development team on a tour of the NEWater plant. They wanted to study the communication and education behind PUB’s successful introduction of reclaimed water to the public. She labelled the plant’s visitors centre as “world class,” saying it not only showed the science, but also provided information on different water resources around the world.
Tap 4 – Desalination
In 2005 Singapore opened its first desalination plant for production of 30 mgd of drinking water. Singspring Pte, Ltd. designed, built, and will operate the plant for its first 20 years. They built a second plant in 2013 to desalinate 70 mgd of sea water. By 2060 desalinated water should be supplying 25% of Singapore’s water demand.
One of the biggest detriments to operating desalination plants in the past has been their excessive use of energy. PUB’s research and development companies are developing new techniques, using electrochemicals, which should cut energy use down by half.
One of those companies, Evoqua Water Technologies, is testing and developing two main techniques: The way that mangrove trees and euryhaline fish extract sea water, and what happens when aquaporins are embedded on membranes. Both of these are instances of biomimicry – exploring and imitating the way nature handles desalination – which results in efficiency that harmonises with nature.
PUB’s next priorities are: Reducing the energy used for all four taps, capturing whatever energy is released during the water cleansing process, and finding additional storage for excess water that can be saved for future use – including possible underground storage caverns. Much of the research developed in the course of satisfying these priorities will lead to additional technological breakthroughs.
According to Prime Minister Lee Hsien Loong, “In recent years, Singapore has gone from managing water as a resource to increasingly leveraging it as an economic asset.”
He is referencing Singapore’s desalination plants, NEWater project, and treatment of urban runoff, which were made possible by R&D engineers working closely with the public to test the technologies they were developing. Involved in Singapore’s water technology centre are now 150 water companies and 26 research centres, some of which are already producing turnkey models for NEWater and desalination plants for sale. In 2012 the government designated US$470 million to further stimulate exports from this sector, anticipating that its water treatment products will soon be in high demand.
There may be a market in California. Ms. Swanson, who now lives there, is saddened by knowing that California is in a severe drought and “that the technology exists to be capturing our street runoff,” and “that the water we use is lost and not recycled. ”
California needs to communicate with Singapore. By developing the breakthrough technologies it has, Singapore can not only meet its own water needs in the present and future, but can also profit by helping other countries meet theirs.
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13 November 2018
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