Plastic in biobins of Hamburg
The fractions of impurities are relevant regarding the quality of the compost. And within Soilcom the partners see the microplastics as a major point of concern in the development of quality composts based on biowaste and green waste.
Since 2017, the German federal quality association for compost is working on a ‘Chargenanalyse’, in which the impurities can be valued optical. With this analysis, Stadtreinigung Hamburg analysed the quality of input material coming from the biobins and of some underground collecting systems. Both the biobins and underground collecting systems were placed in or near different housing systems: single family houses and multifamily apartments.
Generally the bio waste from single family houses was well separated and not so well separated on locations of the multifamily apartments.
After collection the plastics were air-dried and the different kinds of plastic were determined by near infrared spectroscopy. An ATR-FRIR spectrometer was used to validate the qualitative analysis. The plastics found, were mainly coming from unconscious separation of waste. And from the so called bio-degradable plastics. Although the sorting systems of composting plants regularly improved, the aim is to avoid the input of impurities and plastics. Especially concerning bio-degradable plastics there is a large need for more communication and education towards consumers and residents about what to put in the bio bins and what not.