Brainstorming a path for desalination

Some of the latest and most innovative ideas in sustainable and cost-effective desalination practices were raised and discussed at the inaugural National Desalination Research Roadmapping Workshop, held in Perth on 29 and 30 October.

In a collaborative effort to address the future of Australia’s water needs, the National Centre of Excellence in Desalination (NCED) brought together more than 90 industry experts from universities, the public sector and the private sector in the first ever conference of its kind on such a scale.

The NCED launched this year with the aim of planning a path towards the inception of an Indigenous desalination industry comprising scientists and engineers. According to Interim Chief Executive Officer from Murdoch University Professor David Doepel, the task will require significant investment and commitment from government - but Australia is ready for the challenge.

Professor Doepel introduced the conference by borrowing from Coleridge’s The Rime of the Ancient Mariner with “… Water, water everywhere/Nor any drop to drink” as a poignant allegory to Australia’s unique conditions and circumstances, being surrounded by water yet unable to truly tap into its abundance. With this in mind, Dr Thomas Hinkebein stressed the importance of roadmapping the journey towards ensuring sustainable water solutions for the future of Australian cities as well as regional and remote areas.

In terms of real and practical solutions, Professor Doepel said some of the most startling and novel ideas were brainstormed during the seminar. In fact, he said there one particular idea raised by a delegate was considered so novel, one of the facilitators suggested it required IP protection. Which is why, Professor Doepel said, these workshops are so incredibly beneficial.

Aside from the workshopping itself, white paper presentations were targeted specifically at carbon reduction (using large-scale renewable energies) and inland desalination brine management, to cut to the core of using sustainable desalination to support water supply.

The Deputy Director of the UNESCO Centre for Membrane Science and Technology at the University of New South Wales, Associate Professor Greg Leslie, presented ‘Reducing the carbon footprint: it’s more than just the energy’. As Professor Leslie indicated, desalination processes are sensitive to the increases in electricity, so it is imperative to develop strategies to cope with increasing power costs, as well as carbon emissions. For example, with a power cost increase from $0.05/kWh to $0.2/kWh in a two-pass reverse osmosis system (operating at 4.0 kWh/m³ and producing fresh water with less than 150 mg/L TDS and less than 0.1 mg/L of boron), the subsequent water production cost would increase 170%.

Professor Leslie said reducing the energy requirements for seawater desalination is a global objective and the current benchmark sits at 3.5 kWh/m³. Singapore, China, Japan, the US and EU members, among other nations, are focusing on reducing this benchmark to a theoretical minimum of 0.8 kWh/m³. Current R&D from around the world is not only researching improving energy efficiency for current processing techniques but is also considering newer processes. These include forward osmosis, new-generation membrane materials for reverse osmosis, nanocomposite particle membranes and carbon nanotube membranes.

Professor Leslie also said it was the first workshopping conference he’d ever attended on such a large scale and the networking capabilities of the two days were tantamount. Professor Doepel affirmed these comments and said the workshopping kicked off by “getting everybody to do everything” rather than separating the disciplines.

Professor Doepel said another key point of the centre based at Murdoch University is identifying research opportunities, and this is exactly where CH2MHill Regional Technology Leader for Desalination Mr Kenneth Moore focused his attention. Moore’s white paper presentation, ‘Direct Coupling of Renewable Energy and Desalination’, emphasised not only the current application of renewable energies for facilities, but seeing the potential of improving from the challenges we face today. Moore discussed the ever-growing need for inland communities to utilise brackish groundwater reserves and, in turn, the need to develop ‘climate responsible’ water supplies. Moore also emphasised how Australia’s unique reliance on desalination technologies could very well define our place at the forefront of these developing technologies.

In order to achieve facilities powered by renewable energies, Moore said the key is to couple established desalination technologies with different forms of renewable energy systems. For example, geothermal could be used to support traditional distillation and membrane distillation; while both geothermal and solar could support pressure membranes, electrical separation and traditional distillation. Whereas, solar power could support distillation and humidification-dehumidification processes just on its own. Professor Doepel echoed these comments in an interview. “What do we have an enormous amount of in Australia? Sunshine. So it would make sense in our unique Australian conditions to look at solar energy for the production of water.”

Wind energy may provide a source for pressure membranes by way of both shaft and electricity. These combinations, as Moore pointed out, also demonstrated solar power’s ‘dominance’ in providing an alternative energy source. Regardless of renewable energy choices, reducing carbon emissions and even creating carbon neutral plants, the actual cost of powering facilities with any form of renewable energy must be reduced for industry to rely on these technologies in the future.

However, an equally important aspect of discussing desalination and its effect on sustainable practices is responsible brine management. Presenter, Geo-Processors Pty Ltd President and Chief Technologist Dr Aharon Arakel said in an Australian context brine management solutions sourced from other nations have limited applicability in our conditions.

As Professor Doepel initially indicated, the ability to recognise research opportunities was of utmost importance to the Centre’s aims, so Dr Arakel exposed the areas requiring research. He emphasised the need to firstly understand the specific environmental impacts of desalination and promoting research to this effect. He talked of other considerations such as: the beneficial uses of brine in downstream industries, contaminant reductions for maximising this beneficial use, developing regulatory frameworks, the promotion of government participation and site-specific research.

As far as ocean outpour was concerned, however, experts appeared to be comfortable with current technological solutions as deployed in Australia, according to Professor Doepel. ”However, careful monitoring is required to verify that there is minimal environmental impact.” Aggregating this data from around Australia and analysing it longitudinally would also be very helpful, according to attendees.

Professor Doepel said incremental improvements are occurring all the time with the current technology. “On average, we’re getting a 4% improvement in efficiency and cost efficiency per year,” he said. “So over the last few decades there’s been enormous strides and that improvement is still occurring. But where we have opportunities we haven’t looked at enough is with the carbon footprint; so like every industry, we need to look at minimising that.”

In regards to the conference itself, Professor Doepel said it was about “bringing together the nascent desalination community in Australia” and allowing people to find friendships and natural affinities within the field because “you can’t make people work together but rather help develop mutual respect”.

Murdoch University received $20 million over five years to host the centre as part of a $12.9 billion Water for the Future plan as well as up to an extra $5 million support from the Western Australian state government. To learn more about the Commonwealth plan, visit www.environment.gov.au/water.