Investigation of Biogas Production Potential of Fruit Wastes and Sewage Sludge by Co-Digestion Method

Abstract

Anaerobic co-digestion strategies are needed to enhance and improve biogas production, especially when treating certain residues such as industrial organic wastes and sewage sludge. This study presents a research on the anaerobic co-digestion of the apple, pomegranate and black carrot wastes, which are exposed in the fruit processing industry, together with the sewage sludge of a domestic wastewater treatment plant. With the aim of maximising biogas yields, a series of experiments were carried out under mesophilic conditions in the fed-batch system which lasted for 30 days. For this purpose, single, double, triple and quadruple waste mixtures were prepared by diluting with the wastewater belonging to the fruit processing industry in such a way as to provide a rate of 8% total solid concentration. The maximum value obtained was 839.53 mL for the co-digestion of a mixture of 75% fruit waste and 25% sewage sludge. The lowest value obtained was 170.80 mL for the mixture of 100% pomegranate wastes. The results obtained from the study supported that co-digestion of different organic wastes increased biogas production. In addition, it has been concluded that the co-digestion of sewage sludge with acidic organic wastes has a positive effect on biogas production by preventing the sudden pH decreases.

Keywords: Biogas, Co-digestion, Fed-batch, Fruit waste, Organic waste, Sewage sludge.