Testing soil.

Treating toxic waste with sound waves

CSIRO has patented a process using ultrasound to remediate contaminated soils and create waste that can be disposed of safer, cheaper and quicker than current alternatives.

• 17 August 2005 | Updated 14 October 2011

• The problem
• The breakthrough
• The benefits
• CSIRO testing
• International patents

The problem

What do you do with thousands of tonnes of contaminated soil or stockpiled waste?

This is the question being asked by land developers, industrial and chemical companies, environmental regulators and community groups.  If treatment is needed then how can it be done:

• safely
• quickly
• cheaply? 

We all benefit from the treatment of harmful waste and soils. 

CSIRO has a long history in developing and commercialising technologies and processes for the remediation of contaminated materials. 

The breakthrough

Continuing this trend is a promising recent development in the use of high-power ultrasonics (HPU) to treat wastes and contaminated soils.

HPU is the use of sound waves at high frequency, in this case to break down harmful substances.

HPU can be used to destroy toxic material in a slurry of solids in water.  CSIRO scientists have found a way to harness that potential in a manner that is both rapid and effective, providing near total destruction of most contaminants in a matter of minutes.  

Trials to date have found the process can be successfully applied to a wide range of common toxic materials and contaminated soils. It has the potential to provide an effective alternative technology for those with a need for remediation solutions.

The benefits

Of great interest is the fact that HPU is a low temperature process which means that dioxins are not created. Dioxins are carcinogenic substances that can be formed from waste material that is subjected to high temperatures. 

The technology may also mean an end to dumping of some toxic materials in landfill sites. 

Whilst landfill costs are cheap compared to many destruction technologies, the environmental costs are increasing and the risk of toxic materials leaching from the site into groundwater plumes is always present.  HPU offers a possible alternative that avoids the risks of both dioxin formation and leaching. 

A final bonus is that the process is also likely to cost less than the generally lowest-cost alternative of landfill disposal.

CSIRO testing

CSIRO Industrial Physics has tested the process on a large number of toxic materials and has also built a pilot plant at its Lindfield facility for process optimisation.  More trials are planned and a process of commercialising and scaling up the technology with interested parties has also commenced.

International patents

Assisting in the commercialisation is the technology's strong patent position with recently granted patents in several countries, including Australia and the United States. 

With the soil and waste remediation market demanding alternative, effective and less costly technologies, CSIRO is looking to drive a positive impact for Australia and commercial success for its partners and itself.

Read more about how CSIRO's Enzyme product removes pesticides from water.