Water scarcity drives water efficiency
By Tony Arnel, Global Head of Sustainability, Norman Disney & Young
Friday, 07 April, 2017
Water scarcity already affects every continent. Around 1.2 billion people — or almost one-fifth of the world’s population — live in arid areas with water shortages. Another 1.6 billion people — one-quarter of our global population — face water shortages as a result of climate change.
In Australia, water conservation appears to have fallen off the radar. A decade ago, as drought ravaged the country, our attention was firmly focused on how to shore up our precious water resources. But times have changed. Dams are full, desalination plants have stalled and policymakers are more concerned with energy efficiency as they tackle climate change.
But we cannot afford to be lulled into a false sense of water security. According to the Climate Council, water inflows to key Sydney dams could decrease by as much as 25% by 2070 if greenhouse gas emissions continue on their current trajectory. Annual water demand will outstrip supply in Perth and surrounding regions by as much as 85 billion litres by 2030 — and that’s enough water to fill 34,000 Olympic-sized swimming pools. Average annual stream flows to Melbourne’s four major water harvesting storages could decrease by around a fifth by 2050.
As the driest inhabited continent, Australia must invest in technology and projects that drought-proof our cities and our economy.
So how do we guarantee the water security of our cities?
When your densely populated nation has no independent source of fresh water, like Singapore, scarcity drives self-sufficiency.
In less than 15 years, Singapore has invested in the infrastructure required to become a world leader in water management. The foresight of Singapore’s utility agency means more than half of its water supply is met by a ‘four tap’ strategy. Rainfall, collected in artificial reservoirs, accounts for around 20% of the nation’s water supply; reclaimed water, or what the Singaporeans call ‘NEWater’, meets 30% of demand; while seawater desalination provides a further 10%. The remainder is imported from neighbouring Malaysia.
The first production plant for recycled water opened in 2002. Using an innovative four-stage treatment process — conventional combined with microfiltration, reverse osmosis and UV treatments — means the water is drinkable. Singapore’s first desalination plant opened in 2005, with another plant of double capacity currently in construction. Singapore’s water catchment area has also expanded over the last five years — and now covers two-thirds of the city-state’s land surface areas — with the completion of the Marina, Punggol and Serangoon Reservoir in 2011.
Public education campaigns have also made their mark, with consumption falling from 165 litres per person per day in 2003 to 155 litres in 2009. The government’s target is 140 litres by 2030. Practical schemes, such as water efficiency labelling for taps, showerheads, toilets and washing machines, have also helped consumers make informed choices.
Singapore’s ultimate goal is to be self-sufficient, with 40% of water from recycling, 30% from desalination and 20% from rainwater collection.
The Singaporean Government continues to invest in R&D to identify more cost-effective ways of treating, recycling and supplying water. It is building a reputation as a ‘hydrohub’ for water science and technology, and is contributing expertise to large water projects in China. The government believes everyone in Singapore has a stake in water — as a necessary resource, an economic asset and an “environmental treasure”.
Australia can learn from the lessons of other nations whose battle with scarcity has led them to diversify their water sources and adopt innovative capture techniques.
In Morocco, for example, steel poles, hung with black polymer nets, are harvesting condensed fog from the nearby Atlantic Ocean. The technology, designed by researchers at the Massachusetts Institute of Technology (MIT) School of Engineering in the United States, has been rolled out in countries as diverse as Eritrea, Chile and Yemen.
In Saudi Arabia the $9.4 billion desalination plant on the Persian Gulf covers miles of oceanfront real estate, and pumps more than seven million litres of potable water into Riyadh each day. Saudi Arabia leads the pack in the desalination race and now contributes 18% of the world’s desalinated water.
And in New York, two alternatives to conventional rooftop surfaces are being tested — green roofs to absorb stormwater runoff and blue roofs to capture it. Water from blue roofs is being used to supply irrigation, cooling systems and a host of other non-potable uses.
While there are innovative water-wise projects abroad, there are also inspiring case studies closer to home. And these case studies are being found in unexpected places.
In Queensland’s Nebo, for example, a large maintenance facility for coal trains is harvesting and recycling 85% of the water captured on-site, thanks to a range of clever strategies implemented by NDY. Rainwater is collected and treated using three independent filtration systems — and as a result is clean enough to drink. Wastewater from the sticky coal dump pit is treated and re-used in the locomotive washdown area. And an aerobic system treats all blackwater, which is then re-used for toilet flushing. Together, these initiatives ensure the facility can operate without being reliant on mains water.
Meanwhile, an upgrade to the Metricon Stadium at the Gold Coast in preparation for the Commonwealth Games has delivered water tanks with a total capacity of 650,000 litres. This is complemented with a whole-of-membrane fabric roof which can harvest water at eye-watering rates. An impressive 100% of water collected can be used — for toilets, urinals, general washdown of stadium concourse and seating areas, as well as watering of the grounds.
And at Monash University, a precinct-wide stormwater harvesting system enables large amounts of water to be stored and distributed around the campus. More than 10.6 billion litres of water are used each year for irrigation and toilet flushing, but 93% comes from the stormwater harvesting system.
Without water, there is no life. Without water, there can be no cities. When we envisage our nation in 20, 50, 100 years’ time, we must imagine an urban water network where no drop is wasted. Achieving this goal may be difficult, but if we scale up our successes, diversify our sources and keep our water clean and close to home, Australia will be well on its way to a future that’s water secure.
*Tony Arnel is the global director of sustainability at engineering consultancy Norman Disney & Young and works worldwide across all NDY offices and market sectors. He is the company’s key strategist for Sustainability.
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