Characterization and implications of volatile organic compounds release from raw and torrefied biogenic refuse-derived fuel components

The torrefaction of waste biomass to produce refuse-derived fuel (RDF) offers a promising route for waste valorization. Yet, the release of volatile organic compounds (VOCs) during this process raises concerns regarding environmental and occupational safety. This study investigates VOC release from four biogenic RDF components (cellulose, chicken meat, pine sawdust, starch) torrefied at 200–300 °C. Ninety VOCs were identified and characterized for their properties. Significant differences in VOC composition were observed among the feedstocks: cellulose exhibited the lowest release levels, dominated by small aldehydes; chicken meat released diverse nitrogenous and sulfur-containing compounds; pine sawdust emitted terpenes and lignin-derived aromatics; and starch produced abundant furans and acids. Hazardous VOCs such as furfural, dimethyl disulfide, and toluene were identified. Cross-referencing with the EU Classification, Labelling and Packaging (CLP) regulation revealed twenty-three VOCs associated with health- and environment-related hazard statements, demonstrating that a substantial fraction of the released compounds is of regulatory and toxicological concern. Notably, protein- and lignin-rich components produced the most toxicologically relevant profiles. These findings demonstrate that VOC release from RDF cannot be adequately managed using uniform process assumptions and instead requires feedstock-specific assessment and control strategies. The component-level approach enables targeted risk mitigation strategies and informs policy development for waste-to-energy applications. Future work should assess VOC interactions in mixed RDF and explore mitigation technologies for hazardous emissions from thermal processing. • Biochars derived from waste biomass can generate toxic emissions. • Hazardous VOC emissions from biogenic RDF components were systematically analyzed. • 23 hazardous VOCs were identified and cross-referenced with EU CLP labels. • Chicken meat releases nitrogenous and sulfurous toxic VOCs at high levels. • Pine sawdust emitts terpene-rich VOCs typical of coniferous lignocellulosics.