Consumers confused ‘Where to dispose biodegradable plastics?’: A study of three waste streams

Biodegradable plastics, either fossil- or biobased, are often promoted due to their biodegradability and acclaimed environmental friendliness. However, as demonstrated by previous literature, considerable confusion exists about the appropriate source separation and waste management of these plastics. Present study investigated this confusion based on manual sorting analyses of waste sampled from packaging waste (P), biowaste (B) and residual waste (R) in an urban area of Austria. The results were evaluated relative to near-infrared sensor-based sorting trials conducted in a German urban area. Although existing literature has focused on waste composition analyses (mostly in stand-alone studies) of the three waste streams, the present study focused on identifying the specific types of biodegradable plastic items found in each of these streams. Supermarket carrier bags (P = 90, B = 14, R = 33) and dustbin bags (P = 2, B = 46, R = 6) were found in all three waste streams in the Austrian urban area. Similarly, in the German urban area dustbin bags (P = 1, B = 106, R = 3) were the common items. The results indicate that certain bioplastic items were present in more than one bin; thus, hinting that consumers are not necessarily aware of how-to source-separate the biodegradable plastics. This suggests that neither consumers nor current waste management systems are fully ‘adapted’ to bioplastics, and the management of these plastics’ waste is currently not optimal.