Characterisation of the biodegradability of post-treated digestates via the chemical accessibility and complexity of organic matter

Archive ouverte

Maynaud, Géraldine | Druilhe, Céline | Daumoin, Mylène | Jimenez, Julie | Steyer, Dominique | Torrijos, Michel | Pourcher, Anne-Marie | Wéry, Nathalie

Edité par CCSD ; Elsevier -

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED. The stability of digestate organic matter is a key parameter for its use in agriculture. Here, the organic matter stability was compared between 14 post-treated digestates and the relationship between organic matter complexity and biodegradability was highlighted. Respirometric activity and CH4 yields in batch tests showed a positive linear correlation between both types of biodegradability (R2=0.8). The accessibility and complexity of organic matter were assessed using chemical extractions combined with fluorescence spectroscopy, and biodegradability was mostly anti-correlated with complexity of organic matter. Post-treatments presented a significant effect on the biodegradability and complexity of organic matter. Biodegradability was low for composted digestates which comprised slowly accessible complex molecules. Inversely, solid fractions obtained after phase separation contained a substantial part of remaining biodegradable organic matter with a significant easily accessible fraction comprising simpler molecules. Understanding the effect of post-treatment on the biodegradability of digestates should help to optimize their valorization.

• Description
• Sujet/Public
• Outil
• Outil d'anticipation
• Mémoire et thèse
• Gestion