Modelling of swine farm management for enhancement of biogas production and energy efficiency

Abstract A conventional all-in/all-out batch management, applied in most small to medium scale swine farming, often provides an inconsistent feed of wastewater for the biogas system, causing imbalance between the farm’s power requirement and its generation capacity. This study proposed two developed models that could be employed to ease this problem. In Model 1, the operation was divided into two batch intervals, while in Model 2, the operation used four separate batches. The developed models helped avoid an unnecessary long lag phase, allowing more stable anaerobic digestion performance, and a more evenly distributed amount of biogas being produced. Accordingly, the developed models more stably supplied energy for domestic use, achieving 36-44% reduction of the electricity expense, or a saving of 43,782 m3 biogas or 35,834 kWh equivalent compared with that of the conventional management. Moreover, excess biogas which occurred in the conventional management, up to 14,714 m3 or 12,043 kWh equivalent at the peak period, could be reduced by 79-100%, evaluated as a greenhouse gas reduction of 9,441 and 11,902 m3CO2eq by Models 1 and 2, respectively. This suggests that without additional investment, more profit could be attained from the significant reduction of operating cost by proper farm management.</jats:p