From waste to resource: The untapped value of the separate collection of single-use laboratory plastics to enable recycling

In the face of the sustainability crisis, scientific laboratories, as resource-intensive units, must conduct research more sustainably. They are estimated to produce 5.5 million tonnes of plastic waste per year. Clearly, there is a need for greater circularity: Reduce-and-reuse frameworks for laboratory plastics exist to some extent, but none for recycling of disposed single-use articles. Biologically contaminated plastics from life science labs are disinfected by autoclaving after use, transforming them into conventional residual waste that is mostly incinerated, resulting in high CO ₂ eq. emissions. However, this waste stream consists of high-quality polymers, for which (thermo-)mechanical recycling is technically possible. Therefore, we performed a waste assessment of lab plastics and found in a one-week assessment that the majority of the residual waste consisted of recyclable plastics. However, autoclaving causes these mixed fractions to clump together. Thus, we created a separate collection scheme for the two most abundant plastic types, polystyrene and polypropylene, enabling us to retrieve high-quality monostream polymer fractions for (thermo-)mechanical recycling. This study is the first to present a transferable blueprint with detailed instructions for other institutions on how to implement the separate collection scheme. We obtained user feedback on the feasibility and demonstrated 85% user acceptance. Further, this study provides the first quantitative assessment of emission-saving potential associated with substituting incineration with (thermo-)mechanical recycling for laboratory single-use plastics. For two end-of-life scenarios – an institution-specific scenario at the University of Konstanz (waste incinerated in Weinfelden, Switzerland) and a national average (Germany) scenario – we calculated the average annual emission-saving potentials for the extrapolated amount of arising waste to be up to 10.6 t CO ₂ eq. and 7.2 t CO ₂ eq., respectively. Therefore, a separate collection of lab plastic waste offers an easy-to-implement measure to reduce incinerated plastic waste, thereby lowering emissions and increasing the sustainability of laboratory research.