ANAEROBIC DIGESTION OF ORGANIC WASTES FROM AGRO-FOOD ACTIVITIES IN TUNISIA

摘要

Different organic residues from agro-food activities in Tunisia such as slaughterhouse or fruits and vegetables great markets have been characterized (e.g. content in dry matter, suspended solid, total organic carbon and nitrogen) and tested for anaerobic digestion in 100 or 500 mL bench-scale bioreactors and in a 1 m~3 stirred tank digester (Figure 1). These residues are generally disposed of in landfills, causing serious environmental problems due to their composition and volume that are highly variable, and due to their potential pathogenicity. However, Fresh Fruit and vegetable waste is very rich in organic matter (from 86 to 92% in comparison with dry matter), very moist (88 to 90% water), and possess a varying C/R rapport from 15 to 35. It is favorable for methane fermentation and they are rich in protein, fat and carbohydrates that are suitable for biodegradation with methane recovery in order to operate CHP equipment. The thermal and electrical energy generated in these systems is directly usable in the agro-food facilities producing the initial organic wastes. Tunisia is nowadays convinced by the interest of such a process for organic matter treatment.