A new desalination tech, low energy, low cost

Nick Bruse runs StrikeConsulting, a cleantech venture consultancy; hosts the cleantech show on the podcast network; and advises Clean Technology AustralAsia Pty Ltd and the leading advocate of Cleantech in Australia.


Water Availability and Desalination is a hot topic at the moment here in Australia, as in many other areas of the world. Developed countries like Australia are gripped in drought and faced with shifting climate conditions that mean that water availability is becoming more and more pressured.

Around the world in developing countries 1.1 billion people lack access to improved water sources, and nearly 40 percent of the global population does not have access to basic sanitation. source: Worldwatch institute

As with most climate change pressures the solutions to these problems are many and varied including behavioural change and efficiency measures, regulation, new technologies, low cost local solutions and large scale infrastructure projects. All a necessity to deal with this issue.

Recently the i have been observing a range of technology developments and large scale infrastructure projects to deal with this issue.

In a recent episode of Australian Story, we heard about Max Whisson’s dreams of bring fresh water to inland Australia using ‘water roads’ and his latest invention the water windmill.

The CSIRO has recently announced its new partnership to improve membrane technology

The Advanced Membrane Technologies Research Cluster is working to develop the next generation of membrane technology to deliver Australia a safe and sustainable water resource.

Perth Australia has now established one of the largest desalination plants outside of the middle east and set up a 185MW wind farm to power it.

However something that recently came across my desk was this great story out of Mexico of a low energy low cost solution to producing clean drinking water.

The technology works by utilising vapour pressures differences between two large columns of fresh and saline water. The smart part of the technology is that it takes advantage of localised vacuums that can be formed at the top the water columns by using gravity. If you remember your high school science classes this is the same effect that a tube mercury creates when up-ended in to a mercury bath to create a Barometer.

The water vapour pressures above each column are normally in equilibrium, but when the saline water column is heated by only a difference of 10-15 degrees you get a preferential movement to the fresh water column.

This low cost desalination system has been developed by New Mexico State University engineers and can use low grade heat from solar to industrial waste heat to drive the process.

The full article can be found here

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