Effect of Mechanical Pre-Treatment of the Agricultural Substrates on Yield of Biogas and Kinetics of Anaerobic Digestion

Abstract

The effect of mechanical pre-treatment of nine different agricultural substrates minced to particle sizes of 1.5 mm, 5 mm and 10 mm on biogas and methane yields and fermentation kinetics was investigated. The results showed, that for five of the nine tested substrates (grass, Progas rye, Palazzo rye, tall wheatgrass, beet), a higher biogas production was obtained for the degree of fragmentation of 10 mm compared to fragmentation of 5 mm and 1.5 mm. For fragmentation of 5 mm, the highest biogas production was achieved for sorghum silage, Atletico maize and Cannavaro maize-649.80, 735.59 and 671.83 Nm 3 /Mg VS, respectively. However, for the degree of fragmentation of 1.5 mm, the highest biogas production (510.43 Nm 3 /Mg volatile solid (VS)) was obtained with Topinambur silage. The modified Gompertz model fitted well the kinetics of anaerobic digestion of substrates and show a significant dependence of the model parameters H max (biogas production potential) and R max (maximum rate of biogas production) on the degree of substrate fragmentation.

The role of rice husk biochar addition in anaerobic digestion for sweet sorghum under high loading condition

“…Nevertheless, the methane yield and VS reduction could also vary as a result of different between substrate and inoculum. Generally, methane yield of 200–330 NmL/gVS with VS reduction rate of around 50 % from sorghum was reported in the previous studies [ 25 , 26 ].…”

Increasing Biogas Yield from Fodder by Microbial Stimulation of Propionic Acid Synthesis in Grass Silages

“…With 1 ton of sorghum silage, it produced biogas with 54% methane content. The highest cumulative values of biogas production were obtained for Elvira beet, the methane content was 64 % [32]. In our study the average methane content in grass silages was 66.9% and 68.6% for Biogas A and Biogas B inoculants, respectively.…”

Enhancing biogas plant production using pig manure and corn silage by adding wheat straw processed with liquid hot water and steam explosion

“… a m 3 t dm −1 of biogas yield from the dry organic mass depending on the literature data [ 4 ] b m 3 t dm −1 of biogas yield calculated, based on the methanogenic potential of recirculate measured in the experiments in the laboratory scale c 350 m 3 t dm −1 of biogas yield calculated, based on the methanogenic potential of LHW-SE WS according to the laboratory data, measured in the experiments in the laboratory scale d 600 m 3 t dm −1 of biogas yield obtained according to the biogas plant data …”

“…The biogas potential estimated in the experiments was 350 m 3 t dm −1 of biogas yield, but the value estimated from the theoretical and actual yield revealed 600 m 3 t dm −1 of biogas yield from LHW-SE pretreated wheat straw. The difference between the laboratory-estimated and experimentally measured methanogenic potential of wheat straw may have resulted from the positive impact of the different substrates used in co-digestion [ 4 ].…”

“…Biogas substrates vary in terms of the decomposition rate and in methane production yield. Therefore, a combination of feed additives and pretreatment methods should give the highest efficiency of a biogas production while reducing the decomposition time required for a substrate [ 4 ]. There are several methods of substrate pretreatment to improve the decomposition and methane yield [ 5 ].…”