Bio-valorization of palm oil mill effluent waste for the potential production of renewable biomass fuel pellets

Abstract

Aims: The primary aim of this study was to utilize abundant palm oil mill effluent (POME) waste and turn it into a value-added product of biomass fuel with high calorific energy value (CEV) via fermentation and drying process, then simultaneously reduce abundant liquid waste. Methodology and results: POME is available abundantly in Malaysia and only a small portion of it is utilized to produce other value-added products. In this study, fermentation of POME in the presence of bacteria (Lysinibacillus sp.) and fungus (Aspergillus flavus) separately at 37 °C, 180 rpm for 5 days, followed by overnight oven-drying at 85 °C was conducted. Four fermentation medium conditions were performed, viz.: (1) autoclaved POME, (2) autoclaved POME with the addition of Lysinibacillus sp., (3) autoclaved POME with the addition of A. flavus and (4) POME as it is (non-sterile). Conclusion, significance and impact of study: Among all conditions, fermentation utilizing autoclaved POME in the presence of A. flavus evinced the highest CEV of 25.18 MJ/kg. The fermentation in the presence of Lysinibacillus sp. strain revealed high COD and BOD removal efficiency of 59.20% and 320.44 mg/L as well as the highest reduction of oils and grease among other groups with the value of 15.84%. Future research directions are proposed for the elucidation of co-fermentation in the presence of both Lysinibacillus sp. and A. flavus.