Research into improved desalination process and renewable energy source Tuesday, 09 February 2016

A desalination process which doubles as a renewable energy source is now under study, thanks to a major national award.

Dr Fernanda Helfer is from the School of Engineering at Griffith University. She received a $47,000 AMP Foundation Tomorrow Maker Award, and is joining the Queensland University of Technology’s Professor Graeme Millar. Together, they will lead a project to study the potential of Pressure-Retarded Osmosis (PRO) for application in Australia.

Pressure-Retarded Osmosis utilises a semi-permeable membrane that separates water flows with different salt contents. Through osmosis, the less concentrated solution flows to the high concentration side, equalising the osmotic pressure on both sides.

This creates a solution that, once depressurised via a turbine, produces a renewable electrical energy.

By using Pressure-Retarded Osmosis to assist desalination, it is possible to reduce the industry’s dependence on fossil fuels, and also reduce the environmental impacts caused by the discharge of concentrated brine, a byproduct of the desalination process, into the sea.

In 2015, Dr Helfer co-authored a paper, which identified Australia as an ideal test site for the construction of PRO plants linked to desalination plants.

According to Dr Helfer, the potential applications of Pressure-Retarded Osmosis extends beyond full-scale desalination plants, with benefits for the mining industry and for remote communities too.

“There is potential for this technology to be used in the mining industry, as it produces a lot of high salinity water which makes it problematic for beneficial use,” she says.

“The PRO process can be used to dilute this water and minimise the impact on the environment when it is disposed.”

“PRO is also a potential source of energy for remote and island communities where freshwater is at a premium.”

The researchers will build a portable laboratory unit, which integrates PRO with Reverse Osmosis desalination. This portable lab will be used for ongoing experiments and analysis.

“We are currently working on a joint research paper featuring several scenarios around the application of PRO-generated power in Australia,” says Dr Helfer.

“We are meeting in March to discuss the design and suppliers of components for the portable PRO unit. Hopefully, it will be built and operational by later this year.”

While the desalination aspects of the technology will be a focus, an important aspect of the project is to study the efficacy of using the wastewater effluent and brine from desalination plants as a source of energy.

The researchers warn that PRO membrane technology is still in development: technical and economic improvements are needed to ensure the commercial viability and credibility of the membrane technology. However, this new research will be a step towards confirming its potential, particularly in regards to environmental benefits.