Hi-tech bid to boost desalination
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in Dam Alternatives, Desalination
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Jane Holroyd
May 18, 2007
Some of Australia’s leading scientists have joined forces to find a more energy efficient way of converting salt water to drinking water.
While desalination might be easier for many voters and politicians to swallow than the prospect of recycled sewage, converting salt water to drinking water is expensive and energy-hungry.
But a new project involving scientists from the CSIRO and nine Australian universities aims to vastly improve the efficiency of desalination methods and cut the costs - both financial and environmental.
One of the project leaders, Professor Stephen Gray from Victoria University, said improving the membranes currently being used to remove salts and other unwanted substances from seawater could potentially halve the amount of energy used.
“The energy required to do the separation of water and salt requires quite high pressures,” he said. “When you push the water through the membrane, the water wants to go back and dilute the salt solution.”
Professor Gray said the team would attempt to invent membranes with more permeable pores so that less pressure - and energy - would be required to push the same volume of water through.
Professor Gray said he believed it could be possible to halve energy needs, but said such an outcome was unlikely within the three-year timeline of the CSIRO-led project.
Scientists will also examine ways to improve energy efficiency by slowing the rate at which membranes become dirty or ‘foul’.
The Victorian Government is currently investigating the feasibility of four water infrastructure projects, including a desalination plant.
This week the West Australian Government announced it is to build a second desalination plant. The $400 million existing plant, which began operating last month, now provides about 17 per cent of Perth’s drinking water.
The West Australian Government invested in a wind farm to dampen protests about the environmental costs of desalination.
Professor Gray said that if Victoria began building a desalination plant, improved membranes could be retro-fitted in the future.
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Nanotechnology water desalination for Australia
(Nanowerk News
The delivery of energy efficient desalination in Australia received a boost with the establishment of a major new research collaboration between CSIRO and nine of Australia’s leading universities.
The research aims to dramatically increase efficiency, and reduce the financial and environmental costs of producing desalinated water. The research will help advance water desalination as an alternative water supply option for Australia.
The research addresses one of the biggest challenges currently facing Australia, the delivery of sustainable water supplies. It will focus on energy efficient and environmentally sound desalination and water recycling programs.
CSIRO, through the Water for a Healthy Country Flagship, and in partnership with nine Australian Universities, has established the Advanced Membrane Technologies for Water Treatment Research Cluster. The Membrane Cluster brings together some of Australia’s leading scientists from a range of disciplines in a bid to place Australia at the forefront of novel membrane development.
Led by Professor Stephen Gray of Victoria University, the multi-disciplinary research team will carry out a comprehensive evaluation of existing membranes and develop new energy efficient membranes.
“Many desalination and recycling programs rely on a process called reverse osmosis, where the water is forced through a semi-permeable membrane, removing salts and any other contaminants,” Professor Gray says.
“These membranes need regular replacement and cleaning, but they also require a large amount of energy to force water through what are nano-sized pores.
“We aim to improve membrane design to increase their energy efficiency and reliability, thus reducing the financial and environmental costs of producing desalinated and recycled water.
”We also aim to improve membrane ’anti-fouling’ properties - that is, the ability of the membrane to ‘self-clean’. When contaminants are removed from water, some of them adhere to the surface. These contaminants build up on the surface, increasing the pressure and energy required. Chemicals are used to clean the membranes, but membrane surfaces that are less sticky would reduce the pressure and energy required and the frequency of cleaning.”
The Cluster research will link with and inform related CSIRO research into membrane and nanotechnology, i.e. carbon nanotube water filtration technologies.
Mr Alan Gregory, urban water research leader at CSIRO, says: “In combination with other research projects led by CSIRO, we aim to reduce by up to 50 per cent the amount of energy required to desalinate seawater using membranes. This same technology will have benefits for the treatment and recycling of wastewater.
”This also means we could potentially provide more secure water supplies while minimising greenhouse gas emissions.”
Other partners are: the University of NSW, Monash University, the University of Melbourne, RMIT, Curtin University of Technology, the University of Queensland, Deakin University and Murdoch University.
Funding for the research was announced by the Minister for Education, Science and Training, The Hon Julie Bishop MP, under the Flagship Collaboration Fund Cluster funding. The Fund is designed to facilitate the involvement of the wider Australian research community in addressing the critical national challenges targeted by the Flagships.
As part of the $A305 million (approx US$ 250 million) over seven years provided by the Australian Government to the National Research Flagships, $A97 million was specifically allocated to further enhance collaboration between CSIRO, Australian universities and other publicly funded research agencies.
Source: CSIRO
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