Biomethane production from pellets of horse manure and litter mixture

Climate change caused by global warming forces more and more attention to the use of renewable energy resources. Biogas production from organic waste is considered one of the most correct and environmentally friendly technologies. Various organic wastes are used as raw materials. If this waste has to be transported over longer distances, it is advantageous to granulate it. It has been proven that more gas can be obtained from granules than from non-granulated raw materials during anaerobic fermentation. In this study, it was determined how much biogas (biomethane) can be obtained from pellets of horse manure and three different bedding mixtures. The amount of biogas (biomethane) production was studied in a laboratory device with 16 bioreactors. Their volume was 0.75 liters each. Three different mixtures of horse manure and litter were prepared: a) with fine sawdust (<1 mm) and hay and straw residues (M1) b) with a large amount of hay and straw (also long) (M2) c) with coarse sawdust and hay and straw residues (M3). The bioreactors were placed in a thermostat and the operating temperature was set to 38°C. The study lasted for 30 days. The following results were obtained: 0.451 (0.203) L·g-1DOM of biogas (biomethane) was obtained from mixture M1; mixture M2 yielded 0.494 (0.212) L·g-1DOM of biogas (biomethane) and mixture M3 yielded 0.468 (0.253) L·g-1DOM of biogas (biomethane). In two bioreactors with M3 mixture pellets the enzyme concentrate Metha Plus was added. Its addition improved biogas (biomethane) production: 0.497 (0.278) L·g-1DOM. The study showed that all three mixtures are well suited for biogas (biomethane) production.