UK experts have developed a new technology to clean up tonnes of contaminated land using microwave heat.

The need
Industrial land or brownfield sites can contain dangerous contaminants that need to be removed before sites can be reclaimed for residential or leisure purposes. European legislation, including the EU Landfill Directive, as well as the phasing out of Landfill Tax exemptions for contaminated land introduced in 2008, have increased the need for new and more efficient technologies to clean up contaminants. These include potentially carcinogenic pollutants that not only put human health at risk, but the soil and water supply too.

The results
Residues of hydrocarbons such as diesel and petrol as well as other potentially dangerous pollutants are often left behind on land used by filling stations and industry. These contaminants need to be removed before housing can be built safely on the site, but the process is complex and time-consuming.

Heat has long been used to separate and remove pollutants in a process known as thermal desorption, but a UK-based project has now found a way of using microwave-based heat which is faster, more efficient and more environmentally friendly than traditional heat sources such as gas.

The Waveland team includes six UK-based small and medium-sized businesses with combined expertise. The team spent three years working with business strategists Pera Innovation, the University of Nottingham and experts in industrial microwave processing, to develop a new microwave-based thermal technology which uses half the energy of traditional methods.

As the heating time for microwaves is extremely short compared to conventional heat sources, the process of removing contaminants from soil or water is much faster, resulting in significant labour and energy savings.

The Waveland project has also shown in test results that the microwave heat source is safer and more effective, there are fewer transportation costs and it results in less waste going to landfill.

The machines which will carry out the cleansing will also be able to work on sites that are difficult to access using traditional energy sources due to their small size.

The technology is unique to the UK and has been patented.

Next steps
After success in the laboratory, the search is now underway to find an equipment manufacturer to build the machines so the technology can be tested in harsh operating environments. Developments have been hampered by the downturn in the economy: the crash in the housing market has meant less demand for land remediation. However, those behind the project believe the future market potential is huge. In the UK alone there are up to five million tonnes of land that could benefit from the faster and more efficient process of cleansing land of pollutants. Across Europe there is up to 25Mt of potential land a year, and growing.

Innovation Results : Microwave clean-up

Printable version (pdf)View/Download