Development of combined plant of biogas and bio solid-refuse-fuel from swine manure slurry

An environment-friendly treatment of organic waste like swine manure and food waste is considered to be big challenge, because the residue of organic wastes after anaerobic digestion contains still high amount of undigested organics and is not allowed to dump to ocean by international regulation. The residue from anaerobic digestion of organic wastes, on the other side, has high energy potential because of its leftover organics. In this study a new and integrated treatment process plant of 40 ton swine manure with 20 ton food waste a day has been developed to achieve environment-friendly disposal of swine manure and to produce renewable solid fuel, which has combined two processes of biogas plant and bio solid-refuse-fuel plant. The residue of anaerobic digestion from biogas plant was conveyed to the bio solid-refuse-fuel plant and dried in dryer using the biogas produced in biogas plant as a burner fuel and finally pelletized for a renewable solid fuel. About 30% of total biogas was supplied for 8 h operation of dryer and the leftover 70% was used for generating electricity in the 250 kW gas engine power generator. The produced pellet was analyzed to have good fuel property that meets the Korea Bio Solid-Refuse-Fuel Quality Standard.