Anaerobic Co-Digestion of Oil Palm Frond Waste with Cow Manure for Biogas Production: Influence of a Stepwise Organic Loading on the Methane Productivity

Abstract

Anaerobic co-digestion of oil palm frond waste with cow-manure was evaluated. The study aimed to evaluate a stepwise organic load with an increase solid concentration to the on-going anaerobic digestion of cow manure. The anaerobic digestion process was operated in continuous mode under the mesophilic condition. Results showed that the maximum methane productivity of 1700 ml CH4∙day-1 was obtained when the anaerobic codigestion of OPFW and cow manure was loaded with the substrate concentration between 4 and 8% TS. The pH culture dropped dramatically from 6.9 to 6.3 when substrate concentration was increased from 10 to 12% TS. The acidic pH had restricted the conversion of organic materials in which the COD removal was less than 25% removal. This study is exceedingly notable for the industrial development of waste management processes, which handle and treat tons of organic wastes daily.