RESEARCHERS at the University of Greenwich School of Earth and Environmental Sciences have developed a new treatment process for contaminated land that claims to dramatically reduce clean-up times.
The method can be used on its own or to complement other ground treatment techniques. A granular binder containing products that react with carbon is added to contaminated soil and carbon dioxide is then pumped into the mixture. The three materials rapidly combine to produce a 'very stable' cement.
The reaction mimics the natural process of a more gradual take-up of carbon dioxide. Heavy metal contaminants form as insoluble salts and are trapped inside the cement.
Tests showed the method significantly reduced the leaching of contaminants including a 85% - 98% reduction in zinc, copper and lead. Similar reductions in cadmium, chromium and mercury have also been observed.
Developers Colin Hills and Cecilia MacLeod said while the process is marginally more expensive than other methods, it could treat contaminated land and hazardous waste in minutes rather than days and weeks, reducing overall construction costs.
Hills added that another benefit of the process is the potential to recycle large quantities of carbon dioxide.
A pilot project is planned and an industrial consortium is being formed to market the method. It is hoped the process will be commercially available in about 12 months.