New method cleans stormwater

CSIRO, ScienceAlert 17 Sep 09;

CSIRO scientists have bottled ‘Recharge’ , pure drinking water that was once stormwater.

“This is an exciting demonstration of the value of stormwater and the drinking water that can be produced from it by using a combination of natural treatment processes and engineered methods,” CSIRO’s Water for a Healthy Country Flagship Urban Water Stream Leader Dr Peter Dillon said.

The water was captured in the City of Salisbury, on the Northern Adelaide Plains in South Australia. It was stored under Salisbury in a porous limestone aquifer 160m below ground.

When recovered it was found to meet drinking water health standards.

“The stormwater was first treated by passing it through a reed bed or wetland,” Dr Dillon said.

“This allows particles to settle. It was then injected via wells into a limestone aquifer for storage and months of natural slow filtration through the aquifer.”

After recovery the water was rigorously tested in National Association of Testing Authorities (NATA) accredited laboratories.

For extra safeguard and aesthetic quality the water was aerated, filtered through an activated carbon filter and it underwent microfiltration and ultraviolet disinfection.

‘Recharge’ complies with the same health standards as tap and bottled water.

Dr Dillon said the water demonstrates that drinking water can be produced from stormwater, and that the concept can be part of a suite of diversified water supply options.

“Compared to other common alternative supplies stormwater harvesting is cheaper, energy efficient and has a small carbon footprint.”

“It also avoids the economic, social and environmental costs of building new dams for water storage and shows the value of urban aquifers.”

CSIRO scientists are continuing to test the robustness of the concept to ensure water can be produced that consistently meets drinking water health standards.

‘Recharge’ was produced by CSIRO’s Water for a Healthy Flagship and the City of Salisbury.