Making rain from waste water

30 June, 2014 12:54PM AEST

Making rain from waste water

By Charlotte King and Deb O’Callaghan

Centuries-old technology is being used at a rural landfill to the make potable water through the power of the sun.

Water is a scarce commodity throughout the world, but for those living in a semi-arid region like Mildura, its accessibility is all the more of an issue.

“It’s really important for industry to realise that there are other ways to come up with fresh water,” says Colin Straub, the president of the Sunraysia Sustainability Network.

Mr Straub is behind Mildura’s Eco Village, a demonstration site for sustainable living.

“Industry, and even householders generate water that is wasted after use, but with this system we can demonstrate that it can be recycled quite simply with a solar system, without a huge amount of cost,” he says.

The system he’s talking about uses solar panels to purify storm water captured at the Mildura landfill, water which is then purified through a desalination unit.

“It’s actually above drinking water quality,” he says.

Let it rain, let it rain

Stuart Eastaugh is the marketing manager for the company who built the system.

“It’s exactly how rain is made,” says Mr Eastaugh.

“The feed water runs through the top of the system; as it runs down over the solar element a percentage of it evaporates and condenses.

“So when it goes from liquid, to gas, back to liquid, you end up with pure water.”

The technology uses multiple modular solar panels, which are connected together to produce large quantities of distilled water from a single source, whether it be seawater, groundwater or contaminated dam water.

There is no power source, other than solar radiation, meaning water is supplied to the system through a pump when the sun comes out.

“It has no running costs, it has minimal maintenance costs and it’s sustainable.” he says.

Decentralising the water supply

This solar purification system will be used to irrigate the community garden in Mildura’s Eco Village, but the Australian company behind it is rolling out projects around the world in places where water is scarce, from Botswana to Bangladesh.

Other projects have been rolled out in Aboriginal communities around the Top End, and Ceduna Council in South Australia has just contracted the company to provide half the town’s drinking water from the sea.

Mr Eastaugh says the system allows for water supplies to be decentralised throughout the world.

“You can have one unit per household, or smaller water farms in a decentralised system to produce water for villages or for small towns.”

The technology to do this has been around for hundreds, if not thousands of years, when a glasshouse would use the power of the sun to distill water in a deep basin underneath.

But it’s only recent technological advances that have made it cost effective for households and businesses.

“In those days there was a huge capital cost, low production and high maintenance,” says Mr Eastaugh.

“We’ve now got a modular panel, which is a flow-through system, so we’re going back to low capital costs and high efficiency.”

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