Preparing wastewater samples for analysis at
CSIRO's Floreat Laboratory.
Photo by CSIRO.
Recycled water has not led to human illness anywhere in the world, clearing the way for Western Australia to increase its reliance on reuse of wastewater, a Perth forum was told on 14 March 2008.
Dr Simon Toze, Principal Research Scientist with CSIRO’s Water for a Healthy Country project, said there was a high degree of confidence among scientists that modern water treatment processes could safely filter out microbial pathogens to a level where they were no longer harmful to human health.
As a result, he said there was great scope for increasing the country's use of wastewater, including harvesting more stormwater, treating industrial discharges, re-using grey water in homes from laundry and bathroom water and even treating sewage effluent for a range of uses - but not necessarily for drinking.
Dr Toze said research was now at the fine-tuning stage of improving water quality.
He said water in Australia was treated to such a high level that it would be regarded as excessive by some overseas proponents of recycling.
Although not yet widely used in Australia, water recycling had been practised in a managed, scientific way since the 1920-30s in many parts of Europe and North America, according to Dr Toze.
“In all the work done in the world, nobody has ever brought up a health risk where somebody has fallen sick from recycled water,” he said.
“We don't believe it is a problem.”
He said the science was now focusing improving the efficiency of water treatment processes by reducing energy costs and greenhouse gases.
Other research was looking into how the filtering effects of reservoirs and aquifers removed pathogens.
He added that Australia did not necessarily have to go so far as to recycle sewage directly into drinking water, as was being successfully done in Namibia.
Instead, he said we could look at using treated recycled water to recharge acquifers in a properly managed way.
“It can be treated to a level where it can be put back into a reservoir or aquifer and eventually, 10 or 15 years later, it comes back into the drinking water,” he said.
Dr Toze, a microbiologist, has focused his research on the behaviour of microbial pathogens in groundwater and biogeochemical changes following managed aquifer recharge.
He has responsibility for the management and research direction of projects with a combined value of more than $6 million, in particular, two recent projects co-funded by the WA Premier’s Water Foundation, Water Corporation and CSIRO.
Dr Toze was among speakers at a forum looking into the use of wastewater recycling held at the University of Western Australia on March 14.
Other speakers included former Toowoomba Mayor Dianne Thorley, who made national headlines with her push to introduce recycled sewage into the Queensland town's drinking water.
Despite the Toowoomba community voting against the proposal in a 2006 referendum, the city will be connected to Brisbane’s recycled water supply by 2009 as part of a Queensland State Government initiative announced in January.
The Conservation Council of WA's Water Policy Officer, Steven McKiernan, said he hoped the forum would help the WA Government to see that it was possible to improve on its target of sourcing 30 per cent of the State's water supply from recycled water by 2030.
He said a two-pronged attack was needed, focusing on reducing water usage per person, and increasing reliance on recycled water.
Mr McKiernan pointed out that not all wastewater needed to be treated to drinking level.
Semi-treated recycled water could be piped into homes for jobs where grey water was sufficient, he said. This had been done in a South Australian community where recycled water was piped into a new housing community in specially coloured pipes separate from drinking water, so that the recycled water could be used for watering gardens and laundry, instead of wasting drinking water on these chores, he said.
Communities should also have small treatment plants to enable using recycled water on public open spaces such as ovals and other sporting grounds, he said.
Industry could also make much greater use of recycled wastewater, he said.
“You don't need potable water for a lot of processing or for dust suppression in mine sites,” he said.
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