Carbon, Energy, and Nutrient (CEN) Footprint from Anaerobic Mono-Digestion of Oil Palm Empty Fruit Bunches and Hydrolysis Residues Maria Angelia, Nimas Mayang Sabrina Sunyoto, Sri Suhartini
Department of Agro-industrial Technology, Faculty of Agricultural Technology, Universitas Brawijaya, Malang, 65145, Indonesia
Abstract
Highly used of fossil-fuel based energy contributes to global warming effect to the environment. Therefore, provision to bioenergy via biomass conversion is vital to anticipate energy crisis in Indonesia. Oil palm empty fruit bunches (OPEFBs) are highly available for feedstock of anaerobic digestion (AD). This study aimed to estimate carbon, energy, and nutrient (CEN) footprint from anaerobic mono-digestion of untreated OPEFBs, treated OPEFBs, and acid and enzymatic hydrolysis residues. Two scenarios were proposed, including AD with combined and heat power (CHP) unit (AD+CHP scenario) for electricity and heat production, and AD with biogas upgrading (BU) unit (or AD+BU scenario) for biomethane production. The modelling was carried out using ADAT software and the best scenario was selected using Zeleny method. The results showed that AD + CHP with a complex and concrete system using acid hydrolysis residues (HCC) selected as the best scenario, giving energy balance of 35,726.1 GJ/year, total emission savings of 0.800 tons CO2eq/year, and nutrient savings of N (4.9%), P (2.9%), and K (1.7%), respectively. The findings confirmed that anaerobic mono-digestion of hydrolysis residues (from bioethanol and xylitol production) are potential feedstock for electricity and biomethane production. With this integrated system negative environmental impacts could be reduced.
Keywords: Anaerobic mono-digestion, carbon emissions, energy balances, nutrient savings, bioenergy
