Turning mining wastewater into rainwater

Jun 12, 2014 by Emily Lehmann
The new treatment in progress to remove a range of metal contaminants.

A new cost-effective technology to treat mining wastewater and reduce sludge by up to 90 per cent has been used for the first time at a commercial mine. The technology, called Virtual Curtain, was used to remove metal contaminants from wastewater at a Queensland mine and the equivalent of around 20 Olympic swimming pools of rainwater-quality water was safely discharged.

Sludge is a semi-solid by-product of and reducing the amount produced has huge environmental and economic benefits.

"Our treatment produced only a fraction of the sludge that a conventional lime-based method would have and allowed the mine water to be treated in a more environmentally sound way," CSIRO scientist Dr Grant Douglas said.

"Reducing the amount of sludge is beneficial because the costly and timely steps involved to move and dispose it can be reduced."

Given the Australian is estimated to generate hundreds of millions of tonnes of wastewater each year, the technology opens a significant opportunity for companies to improve water management practices and be more sustainable.

"The technology can produce a material high in metal value, which can be reprocessed to increase a miner's overall recovery rate and partially offset treatment costs," Dr Douglas said.

Virtual Curtain utilises hydrotalcites, which are minerals sometimes found in stomach antacids, to simultaneously trap a variety of contaminants – including arsenic, cadmium, and iron – in one step.

This video is not supported by your browser at this time.

Dr Douglas and his team developed the technology after discovering that hydrotalcites could be formed by adjusting the concentrations of common wastewater contaminants, aluminium and magnesium, to an ideal ratio and then by increasing the pH.

"By using contaminants already present in the wastewater we have avoided the need for expensive infrastructure and complicated chemistry to treat the waste," he said.

"If required, the treated water can be purified much more efficiently via reverse osmosis and either released to the environment or recycled back into the plant, so it has huge benefits for mining operators in arid regions such as Australia and Chile.

The mine pit following the release of the treated water.

"It is a more efficient and economic way to treat wastewater and is enabling the global mining industry to reduce its environmental footprint and extract wealth from waste."

The licensed technology, which can be applied to a range of industrial applications, is available through Australian company Virtual Curtain Limited.

Explore further: Wastewater technology to assist nuclear clean-up

add to favorites email to friend print save as pdf

Related Stories

Wastewater technology to assist nuclear clean-up

Nov 07, 2013

West Australian researchers have developed an advanced water decontamination process that turns toxic wastewater into near rainwater quality and which they believe could help Japan in its extensive clean-up ...

Recycling astronaut urine for energy and drinking water

Apr 09, 2014

On the less glamorous side of space exploration, there's the more practical problem of waste—in particular, what to do with astronaut pee. But rather than ejecting it into space, scientists are developing ...

Key find for treating wastewater on World Water Day

Mar 26, 2013

A newly developed membrane used to separate waste from water could become key in the treatment of pollutants ranging from acid mine drainage to oil-containing wastewater, as well as in processes ranging from desalination ...

Recommended for you

NASA image: Signs of deforestation in Brazil

5 hours ago

Multiple fires are visible in in this image of the Para and Mato Grosso states of Brazil. Many of these were most likely intentionally set in order to deforest the land. Deforestation is the removal of a ...

Sunblock poses potential hazard to sea life

6 hours ago

The sweet and salty aroma of sunscreen and seawater signals a relaxing trip to the shore. But scientists are now reporting that the idyllic beach vacation comes with an environmental hitch. When certain sunblock ...

Is falling recycling rate due to 'green fatigue'?

6 hours ago

It's been suggested that a recent fall in recycling rates is due to green fatigue, caused by the confusing number of recycling bins presented to householders for different materials. Recycling rates woul ...

Study to inform Maryland decision on "fracking"

9 hours ago

The Maryland Department of Environment and Department of Health and Mental Hygiene released on August 18, 2014, a report by the University of Maryland School of Public Health, which assesses the potential ...

User comments : 0