Industrial waste used to develop non-toxic wood protection

What started as a project developing biofuels for ships, has evolved into an environmentally friendly method for wood preservation. The path to new inventions is rarely straight or predictable, and this has certainly been the case for University of Copenhagen researchers Emil Thybring and Sune Tjalfe Thomsen. For several years, they have been working on a new, sustainable way to impregnate wood without harming the environment.

Today, the wood industry treats timber with heavy metals such as copper to extend its lifespan when used as a construction material. In the pressure treatment process, water with dissolved preservation chemicals is forced into the wood. The problem is that a large proportion of these substances is later leached out when the wood is exposed to rain, ultimately ending up in soil, marine environments and drinking water.

“The toxic substances we introduce into the wood using water to make it last longer also leave the wood with water and end up in nature. It is a serious problem, and one we aim to solve with our technology,” says Emil Thybring, associate professor at the Department of Geosciences and Natural Resource Management.

The wood’s own ‘glue’ – in hyperconcentrated form

The researchers’ method is based on lignin, a natural binding agent in wood that stiffens the material and holds its cells together. Lignin is available in vast quantities as a residual product from the paper industry, where it is separated out and typically burned because it gives paper a brownish colour rather than the desired white. According to the researchers, just 15 percent of the EU’s lignin production could replace the environmentally harmful substances used across the entire EU production of pressure-treated timber.

“It makes perfect sense to take a global industrial by-product and use it as an environmentally friendly alternative to the most widely used – and environmentally damaging – wood protection methods we rely on today,” says Sune Tjalfe Thomsen, associate professor at the Department of Geosciences and Natural Resource Management.

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Source & image credit: University of Copenhagen