The dynamics of macro- and microplastic quantity and size changes during the composting process.

Area of Science:

• Environmental Science
• Environmental Chemistry
• Waste Management

Background:

• Plastic pollution is a growing concern in various environmental compartments.
• Composting is a common waste management strategy for organic materials.
• The fate of plastics during composting requires further investigation.

Purpose of the Study:

• To quantify macro- and microplastics in composting materials.
• To compare plastic generation across different composting plant operational parameters.
• To assess plastic contamination in finished compost products.

Main Methods:

• Analysis of rotting material from two Austrian composting plants.
• Quantification of microplastics (>0.2 mm) at different stages of the composting process.
• Comparison of nine compost samples from three different facilities.

Main Results:

• Microplastics were detected early in the composting process, even after the first turning.
• Shorter turning intervals in the initial four weeks led to higher microplastic generation (approx. 21 particles/week/kg DM).
• Plastic particle concentration in compost ranged from 7 to 232 particles/kg DM, with the highest levels in compost from densely populated areas.

Conclusions:

• Composting facilities can generate microplastics during the process.
• Operational factors like turning frequency influence microplastic formation.
• Compost derived from biowaste in urban areas may have higher plastic contamination.