BIOGAS POTENTIAL OF DIGESTATE AFTER FERMENTATION OF SIDA HERMAPHRODITA SILAGE

Abstract

Lignocellulosic biomass is one of the most widely used substrate in methane digestion. Among plants with a high yield potential, Sida hermaphrodita is particularly noteworthy, due to Sida can be grown on low quality soils and its utilization for energy purposes is not competitive with food crops. Methane fermentation of biomass with such a complex structure usually requires application of pre-treatment methods for efficient utilization of its cellulose and hemicellulose. It is economically justified to control of digestate if substrate was efficiently used. The study aimed to measure biogas potential of digestate after fermentation of Sida hermaphrodita silage. The post-fermentation of two samples of digestate from the reactors operated at organic compounds loading 2 kg/(m³∙d) – S1 and 3 kg/(m³∙d) – S2 was performed. Hydraulic retention time in these reactors was 50 d and 33 d, respectively. Biogas potential of fermented sludge was measured with the use of AMPTS II (Bioprocess control). Biogas production was 0.012 L/g TS and 0.031 L/g TS from digestate’s S1 and S2, respectively. The methane content in biogas was 15% from digestate S1 and 50% from digestate S2. The obtained results suggest that digestate from reactor with organic compounds loading of 3 kg/(m³∙d) still has high biogas potential, and hydraulic retention time in this reactor should be prolonged.

Keywords: hydraulic retention time, organic compounds loading, post-fermentation, Sida hermaphrodita silage

Article DOI: http://doi.org/10.15544/RD.2017.194