Świechowski, et al (2024) Anaerobic digestion of brewer’s spent grain with biochars—biomethane production and digestate quality effects. Frontiers. https://doi.org/10.3389/fenrg.2023.1141684

The process of anaerobic digestion (AD) of brewer’s spent grain (BSG) supplemented with biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More (BC) holds significant potential for both enhancing biomethane production and improving the quality of the resulting digestate. BSG, a byproduct of beer production, is abundantly available and poses environmental disposal challenges. Utilizing BC, produced by pyrolyzing BSG at various temperatures, can optimize AD by boosting methane yield and providing nutrient-rich digestate for use as fertilizer.

In a recent study, BSG was combined with BC at different ratios and subjected to AD at 37°C for 30 days. The methane production was closely monitored, showing a yield of 264 to 325 mL per gram of volatile solids. The primary factors influencing methane production were the substrate-to-inoculum ratio and the proportion of BC added. While the type of BC did not significantly alter methane yield, increasing the BC share from 2% to 50% resulted in a methane production boost of 1.8% to 10% depending on the specific conditions.

The digestate, the residual material post-AD, was analyzed for its fertilizing potential. It was found that the quality of the digestate was largely influenced by the quality of the inoculum and the amount of substrate used. The study concluded that the effectiveness of BC supplementation in AD depends not only on the properties of the BC but also on the operational parameters of the AD process and the quality of the feedstockFeedstock refers to the raw organic material used to produce biochar. This can include a wide range of materials, such as wood chips, agricultural residues, and animal manure. More used .