Losses & Emissions in Plastic Recycling

Publieke samenvatting / Public summary

Plastic losses and/or emissions of microplastics, contaminants should be minimized to facilitate a circular economy. Only in the area of object sorting already quite some effort has been put into the reduction of product losses and emissions that occur in the different unit operations, although not all details are known. In this project we take the full process as a starting point but will focus on the post-sorting steps (grinding, washing, and flake sorting). Until 1 January 2022, the recycling rate was determined by the mass of the so-called DKR streams coming from a sorting facility where stream quality is determined on an item level. This means that labels, surface contamination, closures etc. are assigned to the main object, whereas they are of a different material. As of this year, recycling rates are determined on the washed flake level coming from a recycling line. Because of this change, there is a need for increased understanding of losses and emissions in this recycling line after object sorting.

The project aims to: - Being able to detect and quantify as well as qualify the different losses and emissions in different parts of the cycle. - Identify possible causes of plastic loss and unwanted emissions in the waste treatment process of MSW: o sorting; o shredding; o dry wash; o wet grinding; o cold and hot wash. o flake sorting - Define a mitigation strategy for different causes along complete R-ladder of circularity - Enable recyclers to recycle plastics more efficiently by increasing the yield, without impacting the environment. This project contributes to MMIP6 Closure of industrial chains and specifically to the circular plastics part. With this project we enable the increase of recycling rate and reduction of emissions to the environment.

Korte omschrijving
For this project we will focus on plastics from Municipal Solid Waste (MSW). The different processes along the recycling chain are collection, sorting, grinding, washing and reprocessing (mechanical and chemical). The activities in the project are gathered around unwanted emissions and product loss with a special focus on the post-sorting steps; grinding & washing processes. For the product loss, we distinguish between flake/object loss and formation of smaller items (e.g. during grinding). We address formation, detection, prevention, and removal as: Formation: Disposal, sorting & washing and extrusion Detection: Object level, airborne and suspension Prevention: Disposal, sorting & washing and extrusion Removal / retreival: Airborne and suspension To give the project sufficient focus, we restrict the experimental scope to those processes after object sorting and before extrusion, whereas the desk studies will include the other steps as well. We will explore experimental mitigation actions to either prevent product loss and emissions or retrieve product losses in the process for one or more plastics.

By the end of the project, we will deliver: - Cause description and ranking of emission and plastic loss taking into account: o material / product; o process (including used chemicals); o quantification of emissions and product loss; - Mitigation strategies from high to low ranked causes; o can include technology scan / assessment. These results will be a relevant addition to the plastic value chain to address and partly solve the issue of product losses and emissions to come to a 100% circular system.