Water experts are hoping to overcome the 'yuck factor' and renew the debate over recycled drinking water.
(Transcript from World News Australia Radio)
Water experts are hoping to overcome the 'yuck factor' and renew the debate over recycled drinking water with a report on a method of recycling new to Australia.
They say Australia must secure its future water supply using methods that are safe but efficient.
But as Sacha Payne reports, they've acknowledged bringing the public on side is a major challenge.
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The Australian Academy of Technological Sciences and Engineering report is proposing a new method of water recycling.
Known as direct potable reuse of water, it recycles household waste water directly into the drinking water distribution system.
Currently, there are several locations around Australia that indirectly reuse water, by discharging treated waste water into rivers that then go on to feed into drinking water reservoirs.
Mark O'Donohue is the chief executive of the Australian Water Recycling Centre of Excellence, which commissioned the engineers' report.
Dr O'Donohue says Australia's growing population and drying climate indicates future challenges finding enough water for industrial, rural and domestic use.
"The future climate predictions released by the Bureau of Meteorology show a significantly drying climate around Australia. In fact, Australia's had more than ten significant El Nino events over the last ten years. Water recycling is definitely going to be one component that Australia will need to secure our future water supply."
The Academy of Technological Sciences and Engineering says the end of the so-called *Millennium Drought last year, and the absence of water supply emergencies, make the time right to investigate alternative water supplies.
The report's lead author, Stuart Khan, says the report's recommendation that direct potable water reuse systems be instigated in suitable locations should not be a cause of public concern.
"What I'm keen to make sure is that we don't end up in a situation like 2006 in Toowoomba, where you have the climate cycle, you have the problem hitting you first and then you're really making major decisions on the run and trying to bring the community along with you at the same time."
Despite enduring years of drought, in 2006 residents of Toowoomba voted strongly against recycling 25 per cent of the Queensland city's water from sewage.
They relied instead on water piped from Brisbane's Wivenhoe Dam at a cost to ratepayers of nearly $100 million more than the recycling scheme would have been.
The Toowoomba proposal was an indirect recycling program of putting highly treated water through an environmental buffer before being retreated as part of the drinking water system.
Dr Stuart Khan says his preferred method of direct potable reuse, that cuts out the environmental buffer, is cheaper.
But he concedes the yuck factor -- people's unwillingness to drink what they think is sewage -- needs to be overcome.
Dr Khan says the over-treating of the indirect methods of water reuse was part of the argument for Toowoomba residents opposed to the 2006 plan.
"And one of the problems is that people were saying 'well if this water is so pure, you've gone through microfiltration, reverse osmosis, advance oxidation, chlorination, you have this water up to a very very high level and then you go and drop it back out ino the environment into a muddy reservoir where you've got cattle walking around up to their knees. What's going on here? Maybe our confidence in the purity of that water and the reliablity of that treatment plant is not as high as you're suggesting. And in fact, the research that we've seen come from the US is that people do think that there's a message there that does make more sense to be able to say that if we're investing this energy and money into treating this water to such a high level, why do we need to throw that all away and start again?"
Dr Khan says studies in the United States show that as people become more familiar with the idea of water reuse, public acceptance grows.
He says Australia is catching finite amounts of water which is used once then, in effect, piped into the ocean as wastewater.
Dr Khan says there's wide recognition that Australia has to start reusing water, but the alternatives to direct potable reuse are costly to budgets and the environment.
"We can recover it at much lower energy and at much lower cost than doing things like se water desalination. And direct potable reuse, actually taking that water, like Sydney's seawater desalination plant does now, taking water from an advance water treatment plant and piping that directly into a distribution system at the bottom of the catchment rather than piping it all the way back up the hill to, say, Warragamba Dam or in Brisbane Lake Wivenhoe. It's, in my opinion, inevitable and universal, not just in Australia but around the world. I might be talking 60, 70, 100 years away, but it's certainly the way that all water supply systems will need to go at some point."
*Millennium Drought - Australia's driest ten successive years on record