More experts - Recycled sewage ‘can’t be made safe’ ...

WA government says their system will be better than Qld.

WA's scheme will see treated wastewater injected into WA groundwater, where it will remain for 60 years before re-entering the water network.

Excerpt from the West Australian:

Recycled sewage ‘can’t be made safe’

31 October 2008

A leading infectious disease specialist has warned against the Water Corporation’s plan to put recycled sewage into the drinking water supply, saying there is no guarantee the water could be made completely safe.

Professor Peter Collignon, of the Australian National University, said yesterday although wastewater was recycled in several countries, this should only be done as a last resort because of the risks of contamination.

He said human waste contained bacteria and viruses that could cause gastroenteritis, respiratory infection and diarrhoea. Making sewage safe for drinking required a 10-billion fold reduction in levels of the microbes and biological tests were not sensitive enough to check the system.

“The technology has got ahead of the safety testing,” Professor Collignon said. Putting recycled water into aquifers was “a one-way street”.

“Just say it went wrong one day in 365, what do you do when you have all that (contaminated) water in your aquifer?” he said.

His views were backed by Don Bursill, head of the Federal Government’s National Health and Medical Research Council water quality advisory committee, who said even if the technology worked, human error, which accounted for some 80 per cent of water-quality incidents, could not be ruled out.

“There are still opportunities for problems to occur and if it can be avoided I think it should,” he said.

Professor Collignon ignited a furious row this week by issuing a warning about a Queensland plan to pump 60 megalitres a day of recycled sewage into Brisbane’s main water source, Wivenhoe Dam.

The corporation’s scheme will see treated wastewater injected into WA groundwater, where it will remain for 60 years before re-entering the water network. Recycled sewage could make up 25GL of WA’s yearly consumption by 2020.

The corporation will begin testing the technology at its Beenyup treatment works in Craigie in December next year. Sewage will be finely filtered, subjected to “reverse osmosis” to remove chemical contaminants and be UV-irradiated before being injected into the Leederville aquifer.

Corporation strategist Nick Turner said sewage was “an inherently hazardous source”. But he said the system could be shut down in a matter of hours if the chemical makeup of the water changed and officials suspected pathogens might be present.

He said the Queensland project pumped recycled sewage directly into the water supply, but in WA water would be stored underground for decades, meaning harmful bugs would be less likely to survive.

WA environmental health director Jim Dodds said recycled water would have to meet the same stringent safety standards as for drinking water.

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