Comparative start-up between mesophilic and thermophilic for acidified palm oil mill effluent treatment

Abstract Malaysia is one of the largest palm oil producers in the world and its most abundant waste, palm oil mill effluent (POME), can be used as a feedstock to produce methane. Anaerobic digestion is suitable for treating the POME for methane production due to its tolerance to high strength chemical oxygen demand (COD). This work emphasizes the study of conditions during the start-up of anaerobic digestion of acidified POME between thermophilic (55 °C) and mesophilic (37 °C). The pH of the digester was maintained throughout the experiment at 7.3±0.2 in 1000 ml working volume. The study showed that the thermophilic was much faster to stabilize on the 44th days compared with the mesophilic on the 52nd days. Furthermore, the thermophilic also indicates higher biogas production, which was 0.60 l/l/d compared with 0.26 l/l/d of mesophilic. This result can be supported by the COD removal of thermophilic which also higher.