Anaerobic co-digestion of bamboo biomass and swine manure

There are abundant bamboo wastes in Taiwan, including those refuses from the plants of furniture, artworks and chopsticks, and the harvesting residues from the forests. Traditionally, these wastes were treated by directly burning or dump in the landfill. However, it will result pollution either to the air or soil and groundwater. In this study, these bamboo wastes will be used as the substrate for anaerobic co-digestion with swine manure to produce the methane gas. In the beginning, tests of methane potential of the bamboo biomass were conducted. Four different volatile solids (VS) concentrations (1%, 2.5%, 5%, 10%) of bamboo powder (BP) were mixed with anaerobic sludge (AS) at a ratio of 3:2 (BP:AS). It was observed the test of VS 10% had the highest methane yield of 126 mL/g VS added and a methane content of 52% were achieved. With these preliminary results, the co-digestion of bamboo biomass and the swine manure with five mixture ratios (0:1, 1:3, 1:2, 1:1, 1:0) tested using the semi-CSTR. The hydraulic retention time (HRT) was 10 days. The gas production performance and the organic removal were no improvement at both mesophilic (37±1°C) and thermophilic (55±1°C) conditions in co-digestion. In co-digestion experiment, it was obtained when mixture ratio is 1:3 at thermophilic temperature had the highest methane yield (0.16 L/g VS added).