Anaerobic Co-Digestion of Cow Manure and Palm Oil Mill Effluent (POME): Assessment of Methane Production and Biodegradation Efficiency

Abstract

The performance of anaerobic co-digestion of cow manure and POME was evaluated. The anaerobic composting process was carried out by using semi-continuous reactors under the mesophilic condition (35 ± 1℃). The addition of POME to the on-going anaerobic composting of cow manure was applied stepwise within a cycle of HRT (20 days). Results showed that the anaerobic co-digestion reactor could produce methane at about six times higher (7.2 L CH4) than the control reactor (1.3 L CH4). An increasing of POME loaded to the on-going anaerobic composting cow manure culture (4% to 64%) did not affect pH of the culture in which pH was still stable between 7.11 and 7.5. Assessment of biodegradation efficiency revealed that nitrogen removal of the anaerobic co-digestion reactor was six times higher (21%) than the nitrogen removal of the control reactor (3.4%). This suggested that the anaerobic co-digestion reactor performed sufficiently well in which no organic acid as well as ammonia accumulated in the reactor that could be effective to decompose the organic matters.