Abstract: Anaerobic co-digestion is well established process for treating many types of organic wastes, both solid and liquid and evaluated for biogas (methane) production. The biogas production and some biochemical parameters of anaerobic digestion at 30°C for 40 days were studied for two sets of fermentation media, as affected by two factors: (1) the type of the animal waste pigeon waste, P and rabbit waste, R, and (2) the ratio of animal waste to olive cake which constitute four levels (100:0 for R1 and P1; 80:20 for R2 and P2; 60:40 for R3 and P3 and 40:60 for R4 and P4). The results indicated that there was a decrease in total gas production in the digesters of pigeons and highest production in the first week of the experiment for all digesters, but in experimental groups of rabbit wastes R1 (100:0) the highest production between 29-40 day and the others in the first week only. It is concluded that co-digestion of olive wastes, together with local agricultural residues, such as manure, is a sustainable and environmentally-attractive method to treat wastes and thus convert them from a burden to society to a useful resource. The biogas produced can be used for the generation of heat and/or electricity.
Key words: Anaerobic digestion, biogas, olive cake, animal wastes.
