Co-Digestion of Cow Dung, Poultry Manure, Palm Oil Mill Effluent and Water for Biogas Production: Performance Evaluation of Fixed Dome and Floating Drum Digesters

Biogas production from agricultural wastes has not been fully explored as a means of waste management and production of organic fertilizer. Hence, the objective of this paper was to explore the performance evaluation of fixed dome (FXD) and floating drum digester (FLD) for the production of biogas from the co-digestion of cow dung (CD), poultry manure (PM), palm oil mill effluent (POME) and water (WW) using appropriate standard procedures. Results showed that in the water/manure treatment, the FXD digester produced significantly more biogas (8.18 dm3) at 33°C and pH 6.8 than other treatments. In the POME/manure treatment, the FLD digester yielded the highest biogas volume (8.05 dm3) at 34°C and pH 6.4. FXD digesters were more suited for water/manure treatment, while FLD digesters were preferable for the POME/manure treatment. Analysis of digested slurry revealed N, P, and K contents of 2.54, 1.25, and 7.68 % for FXD digester, and 2.53, 1.76, and 50.14 % for FLD digester. These slurries may serve as high-quality organic manure, replacing chemical fertilizers in agriculture. The study underscores how substrate types, digester configurations, pH and temperature influence biogas production, emphasizing the sustainable potential of agricultural waste utilization.