Membrane distillation
CSIRO research explores opportunities for higher water recovery desalination.
- 2 January 2008 | Updated 14 October 2011
How it works
Membrane Distillation (MD) is a water separation/purification technique, where water is transported between 'hot' and a 'cool' streams separated by a hydrophobic membrane.
The exchange of water vapour relies on a small temperature difference between the two streams.
It is an alternative to other conventional methods such as reverse osmosis (RO) or simple distillation.
Working under mild conditions, MD offers a number of advantages over RO and simple distillation.
Any waste or low quality heat source can be utilized to heat up the 'hot' stream, and the carrying out of the operation is also quite simple due to the fact that the process takes places at normal pressure.
Applications
CSIRO's Advanced Membrane Technology for Water Treatment research team has been exploring the potential benefits of Membrane Distribution in desalination, demonstrating its possible application over a wide range of salinity, from brackish to high salt content water up to the saturation point.
This is a significant advantage compared to RO, since RO is not practicable for concentrated salt streams due to the high osmotic pressure.
It also means that theoretically a high water recovery for sea water desalination (of the order of 80 per cent) is possible, compared with a typical 35-40 per cent for the RO technique.
The ability to work with near-saturated solutions also means that the method can be used to enhance industrial salt recovery processes.
Besides desalination, the team is also investigating the application of MD for removing volatile chemicals from aqueous solutions, which is a common issue in industrial wastewater.
Read more about our Advanced carbon nanotube technology research project.
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Fast facts
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Desalination provides an alternative source of water to supplement Australia's existing water sources
- Most desalination techniques employ membranes as the barrier that separates unwanted particles, organisms and other substances from water
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Membrane Distillation holds promises for higher water recovery desalination
