Anaerobic digestion of palm oil mill effluent (POME) and impact of incorporation with palm oil fuel ash (POFA)

Abstract

Abstract Anaerobic digestion is a favourable technology for the treatment of palm oil mill effluent (POME) and production of biogas. Biological treatment using an anaerobic batch reactor (ABR) augmented with palm oil fuel ash (POFA) was implemented to investigate the impact of POFA on their performances. Two ABRs are fabricated in this study: Control and POFA ABRs, where POFA ABR was operated at 2g/L of pre-treated POFA with potassium hydroxide (KOH) to increase its porosity. Both reactors are kept at room temperature and a daily feed with neutralized raw POME. Treated samples were collected daily to test for chemical oxygen demand (COD) and pH, whereas weekly tests for mixed liquor volatile suspended solids (MLVSS). Results showed that the control ABR is able to reduce up to 94.4% of COD as compared to the POFA added ABR with only 63.3% in 50 days. The addition of POFA into the anaerobic digestion resulted in lower performance in terms of COD removal efficiency by 20.5%. Economic analysis evidenced that with 85,500 m3 of POME, up to 863 tons of biomethane can be produced, showing a large amount of energy can be utilized from the anaerobic digestion of POME as an alternative energy source.