Integration of centralized biogas plant in cold-snowy region in Japan

A centralized biogas plant was built in Shikaoi town,Hokkaido, Japan to treat manure from 1320 cattle heads. The biogas plant was designed to operate at a feeding amount of 85.8 t/day, a hydraulic retention time (HRT) of 37 days and at a digester temperature of 38 °C. In this study, the operational performance of biogas plant, utilization of digested slurry and economic balance were investigated. Since the working conditions of the plant became stable, the biogas production was 2,687 m 3 /day, 92% of produced biogas was consumed in power generation. Average methane concentration in produced biogas was 57.7%. The hydrogen sulfide (H2S) concentration was decreased to below 140 ppm as a result of bio-desulfurization and dry-desulfurization. The average power generation was 3,737 kwh/day and from that 54% of produced biogas was consumed in the facility operation, while 46% was sold to Power Company. About 20,260 t of digested slurry were applied onto 602 ha grassland and agricultural fields. From the results of the operational performance of the plant and the economic balance evidence, it is evident that the centralized biogas plant has a positive effect on the local economy.