20th INTERNATIONAL SYMPOSIUM ON WASTE MANAGEMENT,
RESOURCE RECOVERY AND SUSTAINABLE LANDFILLING / 13-17 OCTOBER 2025

Workshop: From biowaste collection to high quality compost

SESSION F11 / 12 October 2023 / 15:00 - 16:30
Workshop: From biowaste collection to high quality compost
Chair / Presidente: Christian Zafiu (AT)


Biogenic waste represents the largest fraction of municipal solid waste that should be separately collected and used to produce biogas or compost. Composts can be used as a sustainable fertilizer and soil conditioner respectively. However, impurities reduce the quality of composts and must be avoided as much as possible. In particular, plastic pollution that enters the biogenic waste treatment process will be fragmented and will generate microplastics that cannot be removed from the composts anymore and thus are transferred to soil and the environment.
However, even if impurities can be reduced at any stage of the collection and treatment process the initial collection and avoidance remains the best option to reduce impurities. For the avoidance of impurities it is important to know, which impurities – down to the waste item – were inappropriately disposed of in the separately collected biowaste. In the compost plant, impurities can be removed only partly during pretreatment by different technical solutions, as well as after the composting process.

Introductory lectures:

  • C. Zafiu (AT)
    Workshop introduction and welcome

  • P. Beigl (AT)
    Gamechanger biogenic waste? A guideline for representative sampling with consideration of impurities, biodegradables and food waste

  • E. Binner (AT)
    Austrian regulations about impurities in feedstock material and composts (draft of Austrian compost ordinance, 2022)

  • C. Zafiu (AT)
    Macro- and microplastic pollution in composts and the transfer to agriculture and environment

  • Workshop / group discussion ("world café" with 3 groups – i. Avoidance strategies, ii. New technologies and possible regulations to reduce pollution iii. Plastic pollution in composts and soils)

  • Presentation of group outcomes

  • Summary of workshop and outlook