Investigation of Biochar Ratio, Pyrolysis Temperature and Digestate Type Impact Over Nitrogen Losses Along Digestate Composting

• Published in: Waste and biomass valorization Vol. 15; no. 8; pp. 4807 - 4821
• Main Authors: Firmino, Matheus Vieira, Trémier, Anne
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2024; Springer Nature B.V; Springer
• Subjects: Aerobic biodegradation; Agricultural wastes; Ammonia; Biodegradation; Charcoal; Composting; Emissions; Emissions control; Engineering; Environment; Environmental Engineering/Biotechnology; Environmental Sciences; Immobilization; Industrial Pollution Prevention; Municipal solid waste; Municipal waste management; Nitrogen; Nitrogen cycle; Organic wastes; Original Paper; Parameter identification; Physical characteristics; Physical properties; Pyrolysis; Renewable and Green Energy; Soil investigations; Soil pollution; Soil temperature; Solid waste management; Solid wastes; Waste Management/Waste Technology; Aerobic Degradation; Organic Waste; Nitrogen Emissions; Biochar Characterisation
• ISSN: 1877-2641; 1877-265X
• DOI: 10.1007/s12649-024-02516-1

Solid digestate is often stocked or composted before its utilization due to the short legal period for soil spreading in the EU. These practices generate environmental pollution through nitrogen emissions. Biochar-supplemented composting has proven to be a promising strategy to address this issue. However, the main parameters to minimize nitrogen losses during digestate composting with biochar have not been identified. In this view, the current work studied the influence of biochar ratio (0, 5, and 10%), biochar type (produced at 450 and 900°C), and digestate type (produced from agricultural waste and organic fraction of municipal solid waste) over NH 3 emissions and Total Kjeldahl Nitrogen (TKN) losses during aerobic biodegradation. The results show that biochar and digestate type significantly affected TKN losses (p-values = 0.038 and 0.0007, respectively) and NH 3 emissions (p-values = 0.07 and 0.002, respectively). Regarding biochar type, chemical characteristics (total oxygen and acid functions) play a more significant role in the biochar impact on the composting nitrogen cycle than the physical characteristics (surface area). Regarding digestate type, it was hypothesized that biochar addition to organic wastes with limited intrinsic nitrogen immobilization capacity could yield a higher percentage of NH 3 emissions reduction compared to wastes with high nitrogen immobilization potential. Graphical Abstract