Co-digestion of cocoa husks and cocoa leaves: Effect of C/N ratio to biogas and energy potential
Sri Suhartini, Muhamad Wahyu Roisul Hadi, Nur Hidayat

Department of Agro-industrial Technology, Faculty of Agricultural Technology, Universitas Brawijaya, Malang, Indonesia

Abstract

In Indonesia, energy needs are mostly fulfilled from non-renewable fuels. In the longer term, such practices may lead to energy crisis due to problems of resources continuity and availability. Therefore, development on renewable energy is remained as priority for Indonesian Government, one of which is from biomass sources. Indonesia has a vast and abundant biomass sources available for further transformation to bioenergy. Waste from cocoa plantation (e.g. cocoa husk and cocoa leaves), for instance, contain organic materials that are potential for biogas production. This research aimed to evaluate effect of C / N ratio to biogas production and energy potential from co-digestion of cocoa husk with cocoa leaves. The Biochemical Methane Potential (BMP) test operated under batch and mesophilic condition for 28 days were carried out. The samples tested include blank control, positive control (α-cellulose) and co-digestion samples at different C/N ratio in the range of 22 to 25, prepared in triplicate. The results indicated that pH inhibition was not evident during the digestion process. The findings also confirmed that co-digestion of cocoa husk with cocoa leaves at much higher C/N ratio was able to enhance biogas production. Further estimation on the electricity potential showed a potential application of this co-digestion strategy for providing alternative renewable energy sources.

Keywords: bioenergy; biomass valorization; cocoa waste; anaerobic digestion

Topic: RENEWABLE ENERGY AND BIOREFINERY