A study of biogas production from date palm fruit wastes

Abstract

In this work, the biogas production from a new type of date palm fruit wastes was studied. The effect of solid mixing ratio, temperature, and recycled digestate on the biogas recovery was evaluated. The batch anaerobic digester was run at solid mixing ratios of 0.5, 0.25, 0.15 and 0.1 under mesophilic and thermophilic conditions. The results revealed that among the four mixing ratios, the ratio of 0.15 generated the highest biogas yield of 182 L/kgVS with 63% methane composition in biogas. A maximum biogas delivery of 203 L/kgVS was reached using recycled digestate wastes with 25% of the substrate content. Further, results confirmed that the biogas production was higher at mesophilic conditions due to the extra formation of volatile fatty acids at the thermophilic conditions. In order to make the results of this study applicable to the biogas plant operation, the process was carried out without chemical pretreatment, mixing operation, and the addition of external inoculums materials to the substrate.