Biochar removes microplastics from road water runoff

Undertaken by RSK Group company TerrAffix and Kier, the laboratory trials are believed to be the first to look at the possibility of removing microplastics from road runoff using biochar, which is created when organic materials are turned into refractory carbon via pyrolysis.

The trials were carried out at Swansea University and found that there were no traces of microplastics in the road runoff. The solution will next be put on trial on Kier and National Highways’ A417 project, with details of the road trial in design now. 

In a statement, Matt Tompsett, head of environment and sustainability at Kier Transportation, said: “We’ve been aware of the hidden impact of microplastics generated by the highways network for years.

“We wanted to focus on a solution that could be deployed at scale within highway drainage systems. I had high hopes that biochar would be effective at removing microplastic, but the fact that there were no traces of microplastic is fantastic. Globally, there are no published papers at all which look at road runoff and microplastic removal using biochar, so this research is breaking new ground.  As with all good research projects, they raise questions as well as answer them. We now know that biochar is very effective at removing microplastic from road runoff, but we don’t know if this effectiveness diminishes over time, so the next step will be to use in a real-world scenario on our National Highways A417 Major Project to find out.”