Plant and food waste could help clean up land contamination

Published:
An example of a contaminated site
Image shows an example of a contaminated area of land. Supplied courtesy of ERS Remediation

Scientists at Heriot-Watt University are investigating how waste could be used with microbes to clean up contaminated soil.

In 2016, a House of Commons report found that there are over 300,000 sites in the UK contaminated with pollutants like petrochemicals. The economic value of the sites is over £1 billion.

Various remediation methods are available but they mostly rely on intensive treatments that require expensive onsite infrastructure, energy and resource use.

Dr Tony Gutierrez, an environmental microbial ecologist at Heriot-Watt University, wants to find a more sustainable solution that is cost-effective, quick and uses readily available natural resources.

He has gained funding from the Biotechnology and Biological Sciences Research Council (BBSRC) to find out whether a combination of biochar and microbes could be effective in cleaning up soil.

Gutierrez said: “Biochar is the result of putting plant or food waste under a very high heat in the absence of oxygen. It’s a charcoal-like substance that can be used to improve soil quality and yields of agricultural produce.

“There are indications it could be useful to help remediate soil contaminated with toxic chemicals and organic pollutants.

“Being highly porous, biochar could be used as a carrier of certain types of microorganisms needed to remove pollutants from contaminated soil.

“We’re mixing different biochars and microorganisms to find the best combination to clean up contamination.”

The team will use biochar from the University of Edinburgh and combine it with tried and trusted microbes on soil that’s been polluted with petrochemicals.

Gutierrez said: “We’ll be trialling biochar made from agricultural waste, and we have a few microorganisms in mind that are good at degrading hydrocarbons.”  

Professor Frederic Coulon from Cranfield University said: “Biochar has still much to offer to the waste and  environmental remediation sectors, bringing new opportunities that can contribute to heal and revitalise our soil.”

Thomas Aspray from ERS Remediation said: “Bioremediation is underused in the UK due to a lack of understanding and being used incorrectly in the past. For the right project, it can be more economical and environmentally friendly.

“As a specialist remediation firm, we’re excited to be involved in this project to find out whether biochars can help with the delivery and support the survival of microbial degraders for more heavily contaminated sites.”

Gutierrez said: “Soil contamination is an issue all around the world, whether from accidental spills or leaks and gradual seepage of pollutants. It can have serious consequences for public health and the environment.

“We’ll be using waste products and microbes to create a sustainable, inexpensive solution to a manmade problem.”

The team will be trialling different biochar and microbe combinations in laboratory experiments, with a view to final testing at a field site in the UK.

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Sarah McDaid

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