Beitrag zum Recyclingpotential von PET- und PS-Kunststoffverpackungsabfällen

Go, Nicolas Gerry; Pretz, Thomas (Thesis advisor); Flamme, Sabine (Thesis advisor)

Düren : Shaker Verlag (2020)
Book, Dissertation / PhD Thesis

In: Schriftenreihe zur Aufbereitung und Veredlung 78
Page(s)/Article-Nr.: VI, 137 Seiten : Illustrationen, Diagramme

Dissertation, RWTH Aachen University, 2020


Packaging waste is first collected separately as lightweightpackaging waste (LWP waste) and sorted into types of metal and plastic in sorting plants. These pre-concentrates are specified according to trade specifications, such as purity and content of foreign materials. The purity of this specification (named: sorting purity) does not correspond to the real purity of a target plastic. Packaging is considered to be 100% pure, although foreign materials, impurities and moisture significantly reduce the real purity (called: material purity).In this thesis, the processing potential of PET and PS plastic packaging waste was investigated by practical tests. For this purpose, investigations were carried out on used 693 PET bottles from the deposit system and 328 PS packaging from LWP waste in order to determine the mass fractions of the target plastics as well as impurities and foreign materials. The investigations carried out show average target plastic yields of between 73 and 84 wt.% with maximum yields of 90 wt.% (PET) and 78 wt.-% (PS). It can be seen that there is a correlation between the filling volume of the beverage bottles and their PET yield. In addition, the design of the packaging is also relevant. The bottle types with the lowest residual contents had a wide bottle waist and a tapered shoulder, which makes pouring of the liquid easier. In the case of PS packaging waste, a correlation between the amount of residual content and the type of packaged goods can be seen. Packages of viscous packaged goods, such as curd have a residual content of 6.3 wt.%, while in packages with more liquid contents, such as buttermilk, 1.6 wt.% residual content remains. The possible PET yield without including the residual contents indicates that the bottle design has been conceived by the manufacturers in such a way that material purities of 90 % by weight can be achieved. The non-normal distribution of the data indicates the influence of the outliers and, in connection with this, the influence that consumers have with their emptying behaviour. In the case of PS packaging waste, it was noted that foreign materials are placed in the packaging containers before they are disposed. In some cases, this results in a material purity of less than 50 wt.-%. The better consumers empty a package, the higher the yield of the respective target plastic.