default ads for article
Singapore – As Chief Executive of PUB, Singapore’s national water agency, Chew Men Leong oversees the country’s water, used water and drainage systems. He is responsible for ensuring an adequate and affordable water supply for the island’s more than 5.3 million people. Before heading Pub in 2011, Chew spent 25 years with the Singapore Armed Forces and was the Chief of the Republic of Singapore Navy from 2007 to 2011. He earned his Master of Science degree from California’s Stanford University in 2002. He gives us his take on trying to quench Singapore’s thirst for water as many countries across the globe face the same water dilemma.
Does Singapore have enough water? And what are ways it is trying to increase its volume?
As a small island not naturally endowed with an abundance of land to capture all the
rainwater, Singapore has always viewed water as an existential issue. Its early years were fraught with a series of water challenges including flooding, sanitation and pollution problems. Investments in critical environmental and water infrastructure had to compete with the pressing need for economic development. Notwithstanding this, the provision of a safe and adequate supply of water has always been a top priority.
As the national water agency, PUB manages the entire water cycle, from rainwater collection to the purification and supply of drinking water, to the treatment of used water and its reclamation into NEWater, Singapore’s own brand of high-grade reclaimed water. This has effectively allowed us to close the ‘water loop’ and put in place a robust and diversified water supply strategy known as the Four National Taps – water from local catchment, imported water, NEWater and desalinated water. Our approach to water management can be distilled into three principles that will continue to guide our future plans to ensure an adequate supply of water: to capture every drop of rain that falls on Singapore; to collect every drop of used water; and to recycle every drop of water more than once.
We have been making major investments to build up and diversify our water supply sources in order to strengthen our water security. Over the years, we have also expanded the water catchment areas, which now cover two thirds of Singapore’s land surface and increased our raw water reservoirs from three in the 1960s to 17 today. Our continual efforts in R&D have also led to the introduction of NEWater and desalinated water into our water supply in the last decade, which supplement our local catchment and imported water.
NEWater, essentially ultra-clean, high-grade reclaimed water is the jewel of our water
diversification strategy as it allows us to reduce our dependence on nature. By allowing every drop of water to be used and re-used, it creates a multiplier effect, and is therefore a much more sustainable source of water than adding catchments to collect rainwater, a luxury in land-scarce Singapore. NEWater can currently meet 30% of Singapore’s total water demand, and the plan is to expand NEWater capacity so that it meets up to 55% of demand in the longer term.
R&D (research and development) has been and will continue to be vital in ensuring a sustainable water supply for Singapore. We have to always look at new, innovative ways to contain the rising costs of treating and producing water, to help keep water supply both sustainable and affordable. One focus area of R&D is on reducing energy consumption. These include projects to demonstrate the use of electrochemical technology to desalinate seawater using half the energy. Some exciting R&D in this area is based on biomimicry or mimicking the biological processes by which mangrove plants and euryhaline fish extract seawater using negligible amounts of energy. Another research area is biomimetics, where aquaporins are embedded on membranes. These proteins are nature’s way of shuttling water in and out of cells while blocking out salts.
Extreme weather conditions have brought droughts to California and other Southwestern American states. Has Singapore gone through a similar experience and what measures did you take to resolve this?
Earlier this year, Singapore experienced a prolonged dry spell from mid-January to mid-
March, with little rain. February 2014 was the driest month in Singapore since 1869.
To ensure that Singapore’s water needs were met during the dry period, PUB operated the desalination and NEWater plants at close to full capacity. Together, desalinated water and NEWater – which are more weather-resilient sources – can meet about half of the current water demand. The reservoirs were topped up with NEWater to maintain adequate buffers for extended dry periods.
Singapore’s investments in NEWater and desalination over the years have diversified our sources of water supply and strengthened our water security. It is worthwhile to note that the additional capacity was developed within the last decade. In fact, the most recent desalination plant which added 70 mgd to our overall capacity only came online about six months ago.
In tandem with efforts to ramp up supply, we also encouraged members of the community to play their part in conserving this precious resource. For the non-domestic sector, this included stopping leaks promptly, stopping vehicle washing, stopping the use of high pressure water jets and hoses for washing activities, stopping unnecessary watering of plants and turf, gardens and lawn, and switching off water features, fountains, water play areas and cascades.
In the context of the drought that affected the State of California and the West Coast of the U.S., this year’s Lee Kuan Yew Water Prize recipient, the Orange County Water District (OCWD), pioneered work in groundwater management and water reclamation using advanced water reuse technologies.
OCWD’s Groundwater Replenishment System (GWRS) is a visionary water project that
purifies treated used water to recharge aquifers. Its water reuse model is a sterling example of a sustainable water solution that allows us to circumvent the vagaries of nature. This model has inspired programs in other countries, such as Singapore’s own NEWater program and Australia’s Western Corridor Recycled Water Scheme. The real value of recycled water such as NEWater and GWRS lies in their capability to strengthen water supply resilience, especially against weather extremities like dry spells and droughts.
The award of the Lee Kuan Yew Water Prize 2014 to OCWD is in recognition of the
importance of identifying sustainable solutions to such challenges faced by countries around the world. It is also in line with the focus of Singapore International Water Week (SIWW), which is to create a global platform for industry and government to share and co-create innovative water solutions.
Leveraging on SIWW as a platform to advance global thought leadership in water
management, it is critical for countries to look at water challenges differently and more
holistically, and ensure that water is integrated in the urban master planning of cities. SIWW is also aimed at bringing together the world water ecosystem to drive collaborative efforts, share resources and best practices towards the co-creation of innovative water solutions.
How does Singapore capture storm water for use in its water supply?
With no natural lakes and little land to collect rainwater, Singapore’s strategy has been to try and collect and store as much of the 2,400mm of rain we get annually, even from
unprotected, urbanized catchments. However, this could only be done with complete
separation of the rainwater and sewerage infrastructure, good land use and environmental control, to ensure that the rain that falls is not polluted.
Today, two-thirds of Singapore’s land area is water catchment, and rainwater is collected in the 17 reservoirs. Singapore is probably the city with the most extensive urban rainwater harvesting in the world. Marina Reservoir, Singapore’s 15th reservoir and the first right in the heart of the city, is perhaps the best example of our success in urban storm water harvesting. Created with the damming of the Marina Channel to form the Marina Barrage, the Marina Reservoir collects water from some of the oldest and most densely-built up areas of Singapore.
Given the highly urbanized nature of the catchment, PUB has in place a comprehensive and integrated catchment management plan, with pollution control and mitigation measures to manage the water quality in the reservoir. The dam itself is a tidal barrier that serves to block out the seawater. Besides boosting Singapore’s water supply with the creation of Marina Reservoir, Marina Barrage also alleviates flooding in the low-lying city areas and offers a venue for water-based recreation in the heart of the city center.
Urbanized catchments are not new to Singapore as we have been collecting water from such unprotected catchments in densely populated areas since the 1980s. It was a bold move then and even today, this is not the norm internationally. However, with today’s advanced water technologies, all water can be treated to drinking water standards albeit at a cost.
Keeping the catchments clean then becomes a matter of paramount importance. This is why we constantly engage the public to play their part to keep the catchments and waterways clean by not littering as rain that falls onto the catchment will flow and carry the litter to the reservoirs. We also embarked on an Active, Beautiful, Clean Waters (ABC Waters) program to transform Singapore’s waterways and water bodies beyond their utilitarian functions of drainage and water storage into beautiful streams, rivers and lakes that are well integrated with the surrounding parks and spaces. By creating focal points and community spaces out of these waterways and water bodies, we bring people closer to water and cultivate in them a sense of ownership so that they will better appreciate this precious resource and are committed to keep our catchments clean.
With all the major estuaries already dammed to create reservoirs, the next step is to move into tapping the minor catchments. PUB has pioneered a new technology known as the Variable Salinity Plant to harness water from the remaining streams and rivulets near the shoreline. With this new technology, PUB aims to increase the overall catchment area to 90% in the long term.
What role does desalination play in Singapore’s water strategy?
As an island surrounded by water, desalination is a natural step for Singapore. After years of monitoring desalination technologies, especially the positive developments in membrane technologies which led to improvements in cost and performance, desalinated water was added to Singapore’s water sources in 2005. Singapore’s first desalination plant with a capacity of 30 mgd (millions of gallons per day) was also the first project to be awarded under the Private Public Partnership (PPP) approach. Under the contract, Singspring Pte Ltd will design, build, own and operate the plant and supply water to PUB for a period of 20 years.
A second and larger desalination plant, the Tuaspring desalination plant with a capacity of 70 mgd was opened in Sep 2013. With the opening of Tuaspring desalination plant, desalinated water can meet up to 25% of Singapore’s current water demand.
Like NEWater, desalinated water is independent of rainfall and can be used to supplement water from local catchments. We plan to increase desalination capacity to enhance our water supply resilience. We are actively studying the expansion of our desalination capacity over the near term.
However, desalination is an energy-intensive process, and we are carrying out much
research and development work to try to uncover more cost-efficient ways of producing