Clean water alternatives
A UniSA researcher is investigating better, cheaper ways to get clean water through desalination and recycling.
As Associate Professor Linda Zou points out, Australians are being forced to live with less water, so developing new water technology is imperative.
"Climate change, drought and population growth have put enormous pressures on the supply of clean, potable water," she said.
"It’s now critical that we have reliable, alternative sources of water for domestic and industrial uses. Water recycling and desalination offer two viable possibilities."
Prof Zou, who is Deputy Director of the SA Water Centre for Water Management and Reuse at UniSA, is leading two Australian Research Council Linkage Projects worth more than $500,000 investigating better, cheaper ways to get the most from these sources.
"One project looks at water reuse in manufacturing industries. They consume a large quantity of clean water and, until now very limited reuse has taken place, even though many industrial wastewater streams are only slightly contaminated," she said.
"The other project addresses the two most prohibitive aspects of desalination - high energy and maintenance demands."
Desalination technology has existed for decades and most use semi-permeable membranes to separate salt particles from saltwater. Prof Zou, with partner organisations Victoria University, Beijing University of Chemical Technology and Docklands Science Park, aim to significantly improve the efficiency and effectiveness of saltwater desalination. They will do this by modifying an existing alternative desalination technology.
"The alternative desalination technology is called capacitive deionisation which uses low-voltage electrical potential to attract ions in saltwater to a porous carbon surface. Apart from dramatically lowering energy use, this process has the advantage of regenerating the electrodes easily," Prof Zou said.
"This process was first developed in 1996 but it is inefficient, and this is because of the porous surface structure of the electrodes. Our project will produce better performing and lower cost electrode materials and design."
With industry partner, Victorian water utility company City West Water, and researchers from the University of Queensland, Prof Zou is designing a new, sunlight-activated nano-material that will trap dissolved organic compounds in contaminated water and decompose them at the same time.
"The conventional biological treatment processes may not be suitable to remove dissolved organics," she said.
"Our method employs a low-cost material, uses sunlight and eliminates the need for waste disposal of the contaminants. It has the potential to reduce energy consumption and has a wide application in manufacturing industries."
Prof Zou said the proposed process has applications in part of a new global water desalination market worth approximately US$48 billion in the next decade.
"We estimate that there is the potential for savings of up to 80 per cent of the operational expenditure, using this alternative process."
Prof Zou and her team are hopeful of having the new materials designed by mid 2010.