Improvement of Biomethane Potential by Anaerobic Co-Digestion of Sewage Sludge and Cocoa Pod Husks

The objective of this study was to determine the efficiency and theoretical stability of the anaerobic digestion of the wastewater sludge obtained from a municipal wastewater treatment plant, using co-digestion with cocoa pod husks. The chemical structure of sewage sludge, including its high carbon and nitrogen content in carbohydrates and fats, gives it vast potential for biomethane generation. In this study, the main agri-food residues in the geographical area where the study was conducted that could be used for co-digestion were determined, and cocoa pod husks were found to be the best option based on elemental chemical analysis. The results demonstrate that the co-digestion of sewage sludge with cocoa pod husks can produce up to 555.7 L CH4/Kg SV. In this article, we also propose a method for estimating biochemical methane potential (theoretical BMP) based on chemical equations and a systematic review of the most relevant research in BMP.