Biomass charcoal promises soil cleaning solution
16 Jul 2013
Former industrial land polluted with chemicals and heavy metals could be cleaned up for reuse by charcoal made from biomass, according to new research.
This special charcoal, known as biochar, is made from materials such as wood chips, animal manure, agricultural and other natural waste.
The Institution of Chemical Engineers (IChemE) yesterday claimed biochar could hold the key to re-claiming thousands of square kilometres of polluted ‘brownfield’ land across the world.
“Chemical engineers and other fields of study are looking very closely at the potential of biochar,” said IChemE chief executive David Brown.
“It clearly presents an important opportunity to reduce the impact of harmful pollutants in the environment and bring back into use huge areas of unproductive land with global population expected to grow by nearly a third to nine billion by 2050.”
Brownfield sites in China, UK and the US cover an area of 120,000km2
Charcoal has long been known for improving soil fertility and structure. New research is now revealing its potential to control contaminants such as organic pollutants and heavy metals including Lead, Copper, Cadmium and Zinc.
According to a report published last month by Chinese researchers, adding biochar has the ability to lock in chemicals such as Arsenic for slow release into the soil. One study included in the report showed soil treated with biochar made from waste rice straw was able to reduce the movement of heavy metals in soil by up to two-thirds.
The report also includes a study that found that biochar, made from green waste compost, could significantly reduce the take-up of heavy metals in ryegrass, which is widely used in pastures for grazing animals.
In China, the US and UK alone it is estimated that brownfield sites - abandoned industrial and commercial land - covers an area in excess of 120,000km2 equivalent to countries the size of England and North Korea, and the state of Mississippi, US.
