Improving sustainability and circularity of palm oil by anaerobic digestion of empty fruit bunch, mesocarp fibre, and palm oil mill effluent, enabling selfsufficient energy production from biogas

The sustainability and circularity of the production of palm oil can be improved by anaerobic digestion of EFB, MF, and POME. Anaerobic digestion experiments with untreated and steam treated EFB and MF were performed. It was experimentally proven that steam treatment of EFB and MF improves the anaerobic digestibility of these residues. Alternative conceptual palm oil mill set-ups, including anaerobic digestion, were analysed on technoeconomic, environmental, and circularity aspects. The biogas from the EFB, MF, and POME can provide enough energy to be self-sufficient in steam and electricity. If the steam boiler runs on biogas instead of biomass, no cyclone and electrostatic filter are required for emission control, which equalizes the fixed capital costs related to a biogas system. Preventing methane emission from open POME ponds drastically decreases GHG emission. Besides, extra revenues can be obtained from surplus electricity. Moreover, the nutrients and recalcitrant organic matter are preserved in the sludge and effluent, which can be returned to the soil of the plantation.