Increasing amounts of plastics found in biowaste

This critical issue was addressed at the Kasseler Abfall- und Ressourcenforum 2018. The event hosted a meeting of representatives from the national composters associations of Germany, Austria, Switzerland and Italy, the four countries with the most extensive and best-established separate organic waste collection systems in Europe.
Oliver Weber,

The session on the topic, “The problem of plastics in bio-waste and compost – A comparison of the current situation and solutions in four European countries” took place on Wednesday 11 April in the Kongress Palais Kassel and featured presentations from Hubert Seiringer of KBVӦ – Austrian Compost and Biogas Association, Marco Ricci Jürgensen of CIC – Italian Composting Council, Konrad Schleiss of Biomasse Suisse and Bertram Kehres of BGK – German Compost Quality Association.

The Italian Composting Council presented figures about food waste collection in Italy and discussed the results of 45 tests carried out at 27 facilities as part of the “Di che plastica 6” [What plastic are you made of] project, organised in partnership with Assobioplastiche, CONAI and COREPLA, a communication campaign aimed at educating consumers about proper sorting of plastic and bioplastic packaging.

The investigations conducted by CIC showed an average contamination of organic waste collected in Italy of around 4,9%, consisting mainly of non-compostable plastics. The situation is similar in the other European countries, such as Germany, Switzerland and Austria, where the national compost and biogas association has launched the campaign “All in Bio – Alliance for a plastic bag-free Austria”. The campaign is endorsed by the Austrian Ministry for the Environment, Agriculture and Tourism with the goal to ban single use carrier bags and fruit and vegetable bags made from non-compostable plastic, similar to measures already taken in Italy and France and also in Spain from 2020. The project was presented by Hubert Seiringer, chairman of KBVÖ – Kompost- und Biogasverband Österreich, the Austrian association for the production of compost and biogas, which represents 486 plant managers and 56 companies in Austria. Konrad Schleiss from Biomasse Suisse, applauded to the Austrian initiative and stated that it could be extended to the whole of Europe.

Both the Swiss compost analysis data presented by Schleiss and the German ones illustrated by Bertram Kehres, Managing Director of BGK, showed higher plastic contamination levels in digestates coming from anaerobic digestion facilities in comparison to composts produced by aerobic composting plants.

In 2017 in Switzerland, 73,3% of compost samples passed the requirements of the national quality assurance scheme whilst only 50% of the digestate samples was compliant. In Germany, 8,7% of the compost samples and 10,8% of the digestate samples analyzed by BGK in 2017 didn’t pass the quality requirements (note that there’s a significant difference in percentages in the two countries because the Swiss criteria are stricter than the German ones). The reason of the higher contamination of digestate vs. compost is probably due to the more intensive pretreatments and shredding techniques associated to anaerobic digestion. This leads to higher fragmentation of plastics which make it through the system and reach the final product and pollute it. Therefore, the shared conclusion has been that for an efficient and effective recovery of organic waste, one of the main objectives is to eliminate as much as possible non compostable plastic contamination from the bio-waste before reaching the anaerobic digestion and composting facilities.

Christian Garaffa, Marketing Manager for Source Separation and Recycling at Novamont, said, “We are supporters of this event thanks to our 25 years’ experience in the source separation of organic waste. Compostable bags made from the resin Mater-Bi® enable, high captures of clean organic waste. To this respect, cities like Milan are a leading example worldwide: every year, more than 100 kg per inhabitant of clean food waste are being collected thanks also to the use of compostable plastic bags certified to the EN13432 standard. Thanks to this sustainable tool, the collected organics can be transformed into biogas and quality compost thus ensuring the closure of the carbon cycle, fulfilling the requirements of a true circular economy.”


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