Biogas yield of Enteromorpha prolifera under different pretreatment and anaerobic fermentation conditions

For enhancing utilization of green tide algae, biogas production and characteristics of Enteromorpha prolifera were experimentally studied. Biogas yield and volumetric proportion of methane were evaluated under different pretreatment and anaerobic fermentation conditions. When mass proportion of total solid (TS) was 3% and fermentation temperature was 35℃, the biogas yield per unit mass of volatile solid（VS）were 327.1 mL/g and 458.5 mL/g from Enteromorpha prolifera with particle size of 0.15 mm and 1.50 mm, respectively, and the corresponding volumetric proportion of methane were 64.5% and 66.1%; Comparatively, with alkali pretreated Enteromorpha prolifera of 1.50 mm, the biogas yield per unit mass of VS and volumetric proportion of methane were 340.5 mL/g and 69.4%, respectively. With Enteromorpha prolifera of 1.50 mm and TS mass proportion of 3%, the biogas yield per unit mass of VS at 35℃ increased by 31.3% and 7.5% than that of 25℃ and 55℃,respectively, the corresponding volumetric proportion of methane increased by 10.0% than that of 25℃ and was close to that of 55℃; For Enteromorpha prolifera of 1.50 mm and fermentation at 35℃, the biogas yield per unit mass of VS was the highest when TS mass proportion was kept at 6%, the corresponding volumetric proportion of methane increased by 5.3% than that 3% and was nearly equal to that of 10%. It was accordingly that higher biogas yield, volumetric proportion of methane and system stability could obtain from Enteromorpha prolifera with grinding particle of 1.50 mm, TS mass proportion of 6% and fermentation temperature of 35℃. The results can provide a reference for further studies on biogas production of Enteromorpha prolifera and other macro algae.