In a life cycle assessment (LCA) study, Wageningen Food & Biobased Research and TNO compared two processing routes for hot drink cups made of paper: after collection, processing by a paper factory into toilet paper and tissues (recycling), or after collection, fermentation to produce biogas and compost the fermentation residues.
In recent years, various companies and governments have opted for the large-scale purchase of paper coffee cups with a coating of polylactic acid (PLA). After use, these cups are often processed in the energy from waste plant (AEC). But there are other recycling routes: recycling to other paper products and fermentation to biogas plus composting. In the coming years it is expected that no other recycling routes than the current three will be possible.
Climate change and other environmental impacts
In order to be able to make a good environmental analysis, the ReCiPe midpoints method was used in combination with environmental costs. This method expresses environmental effects as damage costs. The so-called carbon footprint, which is a measure of the effect on climate change, was also examined.
The environmental analysis shows that when evaluating the full environmental profile, the recycling route performs best with € 1.22 avoided environmental costs per 1000 cups. This is partly because a large part of the collected coffee cups appear to be suitable for recycling, which avoids the use of primary pulp and in which the avoided environmental costs for cultivation and particulate matter formation are especially important. The fermentation route takes second place with an environmental performance of € 0.45 avoided environmental costs, but still outperforms processing discarded cups in the AEC (€ 0.28 avoided environmental costs).
When only the effect of climate change (CO2 emissions) is considered, the digestion route performs best with an avoidance of 5.4 kg CO2-eq. per 1000 cups collected. This is followed successively by the AEC and then the recycling route. The recycling route scores the least because the CO2 avoided through recycling is limited due to the limited CO2 emissions from the production of primary pulp, while fermentation as well as combustion score well because combustion of natural gas and therefore CO2 emissions is avoided.
In short: Recycling hot drink cups leads to the best environmental performance, but fermentation to biogas and composting of cups leads to a greater reduction in CO2 emissions.
This research was funded by the Ministry of Economic Affairs (EZK).