Simulation of livestock biomass resource recycling and energy utilization model based on dry type methane fermentation system

Abstract

This study was aimed at investigating the local livestock biomass volume for dairy farms in Town A, located in eastern Hokkaido, Japan, and at presenting a model of a biogas plant that enables maximizing the use of the available livestock biomass. Using a dairy farm with 250 animals in Town A as a model for a biogas plant based on dry-type methane fermentation system (dry-type biogas plant), we set the operational conditions to an average hydraulic retention time of 20 days, digestion temperature of 55°C, and methane gas yield of 0.12 Nm3 CH4/kg VSA. We compared the biogas production of our presented model with that of a wet-type biogas plant with the same number of animals. The results showed that the dry-type biogas plant produced biogas at 859 Nm3/day, while the wet-type biogas plant produced biogas at 666 Nm3/day. These results indicate that introducing dry-type biogas plants in all dairy farms in Town A would potentially enable semi-solid livestock manure to be processed, which is not amenable to ordinary composting, in addition to the conventional processes being carried out through biogas plants, as well as lead to an increase in the amount of biogas production.