construction wood

Taking the waste out of waste wood

construction woodGrantham PhD student Florence Gschwend recently won an impressive £10,000 to put into a new business that harnesses cutting edge innovation to generate fuels from hazardous waste wood. The recipient of this runners-up prize in the prestigious Althea-Imperial innovation competition explains how this is truly a win-win solution, solving two problems at once.

Waste is, by definition, something that we don’t want. This could all be about to change as companies involved in waste disposal, policy makers and others increasingly recognise that most of the waste we produce holds economic value which is just waiting to be unlocked.

Unfortunately, our most prominent waste disposal techniques, such as landfilling and incineration, are not well equipped to deal with some of the most hazardous waste. During the disposal process, toxic substances can be produced or released, contaminating our air, water and soil.

A new life for contaminated wood

Construction wood is the hazardous waste culprit that I am most interested in. This wood is the material used for all of those benches and picnic tables that you will (hopefully) be enjoying this summer. Construction wood is also used to make entire houses. If you have seen this wood raw whilst out doing your DIY shopping, you will have noticed its slightly green colour. You might think that this colouring is similar to the green colour of most leaves and plants. But, in fact, it is preservatives containing copper and, in some cases, chromium and arsenic, that creates this unusual hue.

These metals are important – they prevent wooden constructions from rotting away during use. However, when their useful life is over, these same metals make it impossible to recycle the wood for other uses. Incineration is only allowed in special boilers to avoid the release of toxic material. As a result, construction wood often ends up in a landfill site – to the tune of one million tonnes (equivalent to 2,000 Boeing 747 airliners) annually in the UK – where its economic value is completely lost.

Biofuel boost

Meanwhile, biofuels, fuels that are produced directly from plants, are grown on a large scale in the Americas, but are struggling to take off in Europe. There are a number of reasons for their slow uptake, but one prominent reason is the link between food and crops for fuel. Some people question the use of the land for fuel crops. Others make the claim that food prices increase when biofuels are produced from edible biomass.

From an environmental perspective, producing food crops, that often require the use of fertilisers, can have negative impacts on soil quality. Sometimes these biofuels actually produce more greenhouse gas emissions than the fossil fuels that they are trying to replace – thus the active drive to create clear sustainability guidelines for biofuels.

One solution to these challenges is to look for other plant sources for biofuel production, rather than food crops. There are plenty of other options such as organic waste (residues) from agriculture or forestry. However, these other sources of biofuel production give rise to a new set of problems. Many of those residues already have competing applications, for example animal feed. Their conversion to biofuels is also more complicated and costly, often making this a prohibitively unaffordable option.

Enter our new chemistry

waste wood
Removing metals from waste construction wood allows it to be re-used safely.

Here in Imperial’s Department of Chemical Engineering , my team (featuring Dr Agnieszka Brandt and Dr Jason Hallett) and I have developed a new process that can solve both problems at the same time: a genuine win-win solution.

Our innovative process uses a solvent to remove the metals from contaminated construction wood whilst separating the wood into different components – so-called fractions- at the same time. One of these fractions, the cellulose, can be used to make paper, or can be turned into bioethanol or biogas quite easily. The other fractions can be used quite easily to produce other fuels and useful, versatile chemicals. The metals themselves can be recovered from the solvent and can even be reused.

This approach solves our first problem by diverting the previously expensive to dispose of waste away from landfill and turning it into useful products. At the same time, problem number two is tackled with the creation of a non-food crop biofuel. By using waste as a starting point, this biofuel is cheaper to produce, eliminates any food vs. fuel controversy and achieves higher greenhouse gas savings.

Future plans

The £10,000 Althea-Imperial runner-up prize is a great chance for our group to try and make a commercial business out of this process, spreading its application as widely as possible and transforming real waste into real value. We hope that our technology will be help to nudge our society towards a zero-waste future and a cleaner set of materials and fuels in the future. Winning the Althea-Imperial prize has given us an enormous boost, not just financially. It has shown us that our idea is worth pursuing.

Florence althea 160503_althea_021
Florence explains her team’s research during the Althea-Imperial final

The Althea-Imperial programme itself has been an extremely positive experience. It was refreshing to be surrounded by incredibly smart, creative and innovative women. Designed to equip women studying at Imperial with the skills to develop their business ideas, the programme was very diverse, with the training offered covering everything from basic entrepreneurial skills to performance science and one-on-one mentoring with an individually allocated business coach. Participants can then choose to submit their idea for the Althea-Imperial prize. The whole process was inspiring, insightful, and most of all, fun.

More than anything, my recent experiences have made me reflect on the process of propelling innovation from the lab bench into the real world. Academic research is crucial to the advancement of science and as a consequence the prosperity of society. For research to have an impact, it needs however to be implemented in the real world. As a scientist, you can either wait for someone to pick up on your discovery, or take matters into your own hands. From my perspective, as someone who has been directly involved in the discovery and development of a process, I am extremely motivated to invest the time and energy needed in order to see our research transform the way we see waste for good. I hope my fellow scientists will follow suit.

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