Waste: valuable resource for performance materials

Although there is a great deal of interest in the circular economy, the reuse of consumer waste to fully close cycles is not easy. The collection of waste comes with major challenges, waste streams are often too contaminated for proper recycling, and where complete reuse is possible there are high demands on the quality of the recyclates in the newly manufactured materials. Scientists from Wageningen University & Research are working with government agencies, waste collectors & processors, and material producers to develop practically applicable solutions to these challenges.

The recycling of plastic waste specifically has been appealing to our collective imagination for years. While in many European countries the public has enthusiastically adopted separate waste collections systems practice shows that the actual recycling is less impressive.

“Our study of December 2017 of the Dutch situation found that nearly 30 per cent of the packaging is difficult to recycle,” says Christiaan Bolck, programme manager for Renewable Materials at Wageningen Food & Biobased Research. “The reason for this seems to be that factors such as the primary function of packaging (protecting the product), the marketing requirements related to the packaging, and, of course, the costs, are still considered more important than what happens to the packaging after use.”

The recent annual meeting of the World Economic Forum in Davos saw multinationals indicate a desire for all packaging to be 100% recyclable by 2030. “This is a fine ambition but it also shows how far we still have to go,” adds Bolck.

More than just reuse of packaging waste

It is not only plastic packaging that ends up being discarded – drink packaging containing cellulose fibres is another key example. “We are currently working with the industry on the separation process and use of this type of fibres,” Bolck continues. Also other types of daily household waste can be used more efficiently. “Take jeans, for instance” Bolck illustrates. “For 70 per cent they consist of cellulose fibres, namely cotton. In addition, they contain polyester as well as elastane for stretch. It is not yet possible to recycle these so-called mixed textiles with the current mechanical recycling processes. Interesting to know is that we think we have found an efficient route in which the cellulose is extracted, while the elastane and polyester are broken down into chemical building blocks which can be reused to make new polymers.”

Circular value chain adaptations

To realise the turnaround towards both circular and biobased resources for raw materials, we must look more at the entire value chain and include all the parties involved, says Harriette Bos, expertise manager for Policy, Circular and Biobased Chains at Wageningen Food & Biobased Research. “What basically happens is that promising innovations get stuck in the trial stage for too long and in fact a so-called ‘lock-in situation’ arises. Existing systems are maintained for a long time because the chain is not adapted organisationally, or because the new technology is still relatively expensive due to its small scale.”

Wageningen University & Research carefully calculates alternative scenarios, involves parties from the entire chain in innovation projects, and advises the government on the adaptation of laws and legislation. “It is a game that is played on many levels at the same time,” Bos explains. “We try to gain insight into the entire chain and see what is and isn’t possible to actually initiate change.”

Unique set of facilities

Wageningen scientists have a wide range of sorting, grinding and separation processes in house to separate the waste in various streams and remove contaminants. The facilities also include both a mechanical recycling laboratory for plastic waste, and a paper and pulp recycling laboratory for natural fibres. “This combination of facilities is unique,” says Bolck. “They allow us to simulate existing recycling processes in detail and test new recycling processes and pilot setups. This means we can study the functioning of the processes in practice and gain insight into the properties of the resulting recycled materials, such as paper or plastic.”

Four preconditions for circular growth

According to Bolck, a focus on four important preconditions will allow the circular economy to grow substantially in the coming decades. “First, materials must be designed in such a way that they can be recycled with the available collection and processing methods. We should also look at the collection methods themselves. It is important that the components are properly separated, either in advance or at a later stage. This starts with labelling products and informing consumers: the better the information supply, the better the waste separation – in principle, at least.

“The third precondition is separating contaminants in residual and waste products as much as possible in order to enable the production of good-quality new products from clean recyclates. And, last but not least, all residual and waste streams have their own unique functionalities which must be retained as far as possible in the recycling process.”

Bolck sees the circular economy going hand in hand with the biobased economy. “Losses cannot be prevented and the total demand for materials will continue to grow in coming years. This means that new ‘virgin’ raw materials will also still be needed. Only once we make these fully biobased – based on natural resources – will we be able to fully close the cycle.”

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