Valorisation Biologique Des Déchets Agro-alimentaires

Abstract

The agri-food industry generates significant amounts of organic waste, posing a major environmental and economic challenge. Long considered worthless residues, this waste is now seen as a resource within the circular economy. The thesis explores in depth the types, origins and characteristics of agri-food waste, highlighting its potential for recovery through various techniques. Among these, two biological processes stand out: composting and methanisation. Composting is an aerobic transformation of organic waste into compost, used as a soil improver to enhance soil fertility. This process involves several phases (mesophilic, thermophilic, cooling and maturation) and offers numerous agronomic advantages, although it requires rigorous management. Anaerobic digestion, on the other hand, is an anaerobic fermentation process that produces biogas and digestate, representing an effective renewable energy alternative. The thesis also details the optimal conditions and biochemical stages of these processes, as well as their agricultural, energy and environmental applications. Finally, it highlights the importance of integrating these technologies into a sustainable development approach, enabling the reduction of environmental impacts, the generation of added value and the creation of new economic opportunities, particularly in the context of the Algerian agri-food industries.