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Federal Environmental Agency: poor marks for chemical recycling

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Possible alternative to mechanical recycling is ecologically and economically disadvantageous

It should therefore not count towards statutory recycling rates

As things stand at present, recovering materials mechanically from waste is fundamentally better than chemical recycling, both ecologically and economically. That is the conclusion of a recent study by Germany’s Federal Environmental Agency (Umweltbundesamt, UBA). In a background paper on chemical recycling published recently, the federal authority criticises the high energy input required to chemically break down used plastics into their components and then produce new plastics from them. The UBA experts also find it perturbing that chemical recycling produces large quantities of waste and contaminants that cannot be recycled. And the experts also note that the productivity of chemical recycling is poor. Their conclusions: chemical recycling is ecologically and economically not an alternative to mechanical recycling, is not fully developed technically and should therefore not count as part of the recycling rate for material recovery from used plastics.

There are various ways of reintroducing plastics into the material loop. Up to now, they have mainly been recycled mechanically. Chemical recycling is now being discussed as a possible means of complementing mechanical recycling. In its background paper, the UBA explains that this technology is said to have the potential to boost material recycling by opening up the possibility of recycling waste materials that were not previously recyclable, thus making it easier to fulfil the statutory recycling rates for plastics. However, in the opinion of the federal authority’s experts, chemical recycling seems to create more problems than it solves.

Not fully developed and highly risky

In this assessment, the UBA is also in agreement with Environmental Action Germany (Deutsche Umwelthilfe, DUH): the organisation is warning against chemical recycling because it is a technology that is not fully developed and is highly risky, and its environmental impact is barely known so far. DUH fears that chemical recycling could thus become a dead end and hinder important developments for an environmentally sound circular economy.

With mechanical recycling, plastic waste is sorted, washed, melted down and processed into recyclate. This recyclate then serves as the starting material for new products. The UBA explains that chemical recycling is another form of material recovery and involves converting the plastic polymers into their basic chemical building blocks using thermochemical or chemical processes. The products resulting from chemical recycling are suitable as feedstock for the chemical industry to make new plastic products, as well as for use as liquid energy carriers or fuels. 

The UBA writes that the possibility of producing basic materials for the chemical industry might make the newly emerging chemical recycling processes seem to be potentially of great importance, as they could contribute to closing the loop between the supply and disposal industries. However, the environmental agency’s experts dispute the technical suitability of this technology as well as its ecological and economic benefits. In its background paper, the UBA says the actual suitability of the individual processes for plastics recycling has yet to be proven on a large scale, even if the processes as such have already been tested for other types of feedstock. 

Very high energy input, lots of non-recyclable pollutants

The federal authority’s criticism is based in particular on the very high energy input required for chemical recycling. The UBA also criticises the large quantities of non-recyclable residues and pollutants that are produced during chemical recycling. The agency notes that the disposal and processing of these is energy-intensive and is not fully developed technically. Furthermore, the UBA finds the low yield in chemical recycling perturbing: the experts find such a high material loss to be questionable from an ecological point of view.

Environmental Action Germany even doubts whether the term ‘recycling’ is at all appropriate for chemical recycling. The organisation argues that after the plastic has been broken down into the raw material for plastic production, these then have to be completely remanufactured. By contrast, the plastic is not altered chemically in classic mechanical recycling. 

Chemical recycling – it can neither replace nor complement mechanical recycling

That is why the authors of the UBA background paper conclude that diverting material streams that have so far been subjected to mechanical recycling to chemical recycling should be avoided, since at the present time it can be assumed that the technically far less complex mechanical processes are ecologically more beneficial. In addition, the Federal Environment Agency notes with scepticism that the operation of a large-scale plant is associated with high investment and operating costs and is therefore only economically viable with a continuously high throughput. The paper adds that this means that only plastic waste that is available on the market in large quantities and does not compete directly with mechanical recycling could be considered as feedstock for chemical recycling. And the authors of the analysis cannot see such large quantities of waste ...

All in all, the study clearly shows that so far chemical recycling cannot present itself as a means of replacing or complementing mechanical recycling. As the UBA says, the ecological and economic disadvantages and technical deficits are simply too great.

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