Optimizing Biogas Production from Water Hyacinth (Eichhornia crassipes) Through Varied Volatile Solids Loading Rates in Batch Anaerobic Digestion

Water hyacinth (WH) is promising biomass for renewable energy production when combined with livestock manure. However, previous studies have only investigated biogas production at low loading rates. In this study, we investigated the effects of various volatile solid (VS) loading rates (0.5%, 1.0%, 1.5%, 2.0%, and 2.5%) on biogas production using WH in batch bioreactors. pH, temperature ( o C), biogas production volume in five days (L), the total volume of biogas production (L), biogas yield (L/kgVS added ), and methane concentration (%) were measured over 45 days. The results showed that pH and temperature were suitable for methane production. The VS loading rate of 2.5%VS achieved the highest volume of biogas production in five days, while the loading rate of 0.5%VS recorded the lowest volume. Although, the 2.5%VS treatment had the highest cumulative biogas volume, and was significantly different from the other treatments (p=0.001<0.05 ). But, the biogas yield in the 2.5%VS treatment was the lowest yield, and significantly different from the remaining treatments (p=0.001<0.05 ). The study recommends using a 2.0%VS loading rate for optimal biogas when using WH for biogas production. These findings can contribute to the development of sustainable energy sources using WH as a material source for biogas production in the Vietnamese Mekong Delta.