Dampening the desalination debate

Gold Coast Mayor Ron Clarke has had enough of the debate on desalination. In his recent presentation at National Water 2006, he said, "Why debate, just get moving", despite arguments against the technology.

The Hon Ron Clarke MBE presented a keynote presentation at National Water 2006 that explained how the Gold Coast Council is planning to go ahead with a desalination plant to provide residents with a non-rainwater-dependent water source.

Clarke will be better known to some as the Australian sporting icon that set 19 world records between 1963 and 1970. During his presentation, he commented that when touring the world with his sporting career he would only ever drink bottled water, never trusting the local water supply outside of Australia.

Clarke is currently championing the cause of desalination as a long-term solution to the Gold Coast's water supply, although he is quick to say that different solutions will suit different regions and desalination will not be the best solution for everybody.

"Desalination is not the only option for a water supply independent of rain. New methods of supplementing a city's water supply, such as water recycling, could be just as expensive as desalinated water (after all the methodology incorporates similar osmosis processes)," Clarke said.

He suggests desalination as a way to provide a "water supply independent of rain" for the Gold Coast due to its proximity to the "Earth's biggest water storage facility - the ocean".

The major arguments against desalination centre on the disposal of liquid waste (brine) produced during the process and the excessive energy consumption that is required. Clarke refutes these arguments, suggesting that the brine is easy to dispose of by discharging it back into the ocean for dispersal.

As far as the energy consumption debate is concerned, he places the responsibility squarely onto the renewable energy sector. "It's an issue that needs to be taken up by the renewable energy sector to produce a viable renewable energy supply to compete with the cost-effectiveness of coal-fuelled electricity."

He is also looking at another alternative to rainwater that he says "has been ignored by the governments because of its expense". This involves harvesting the water that is always present in the atmosphere and manifests as humidity.

"Air-to-water generators are already being employed by armies, drought relief agencies and even by some offices," he says.

"As the atmosphere rises above the earth to some 20 kilometres and where humidity is more than 30%, these units can extract 'dampness' without limit. As the technology advances, units are emerging that have the capacity to extract around 200-300 litres and more on a daily basis depending on their location, for the cost of operating an air-conditioning unit."

Clarke intends to go ahead with his plans to implement desalination to the Gold Coast as part of the Council's strategy to ensure its region's water supply despite current arguments. His plan of attack for the future is to:

• Raise the Hinze Dam
• Implement a desalination plant
• Look at an air-water generator with the potential to capture 300 L per day
• Require every new building to have a rainwater tank
• Use recycled water for gardens and parks only
• Cut water use per household from 300 to 204 kL a year
• Keep water restrictions in place even when the dam is full