Water Treatment
CSIRO has developed a new cost-effective technology to treat mining wastewater and reduce sludge by up to 90 per cent.
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.
Water is of course a precious resource throughout Australia. Mining is often water-intensive and is estimated to generate hundreds of millions of tonnes of wastewater each year.
Sludge is a semi-solid by-product of wastewater treatment and reducing the amount produced has huge environmental and economic benefits.
Techniques and technologies that can reduce and treat contaminants in wastewater will help mining companies improve water management practices and be more sustainable.
The CSIRO Virtual Curtain technology uses hydrotalcites to trap metal contaminants in the wastewater.
Hydrotalcites are minerals, sometimes found in stomach antacids, which are able to absorb a variety of contaminants including arsenic, cadmium, and iron.
CSIRO found that hydrotalcites could be formed by adjusting the concentrations of common wastewater contaminants, aluminium and magnesium, to an ideal ratio, and increasing the pH.
By using contaminants already present in the wastewater, researchers have avoided the need for expensive infrastructure and complicated chemistry to treat the waste.
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.
At the Qld mine, the CSIRO 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.
Virtual Curtain 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.