ENGINEERING FOR RURAL DEVELOPMENT Jelgava, 28.-29.05.2009. 239 INVESTIGATION OF BIOGAS PRODUCTION FROM RELATIVELY DRY BIOMASS

Abstract. Anaerobic treatment of relatively dry biomass (W=30-55 %) has an advantage, compared to the traditionally used wet biomass, due to lowered expenses of the transportation of raw or finished materials. By the help of laboratory scale 5l digesters biogas production was investigated from different biomass in anaerobic fermentation in the batch process. Inoculum from cow manure finished fermentation process was added in each digester to facilitate the anaerobic fermentation process. The lowest average yield of biogas 185 l kgvos-1 was obtained from fresh sawdust. The methane yield (percentage of methane) obtained from different biomass was the following: fresh sawdust 83 l kgvsd-1 (45 %); old sawdust 91 l kgvsd-1 (46 %); broiler manure with sawdust litter 98 l kgvsd-1 (49 %); broiler manure with slaughterhouse waste 185 l kgvsd-1 (52 %); and grain mill wastes 132 l kgvsd-1 (50 %)