Packing materials improve biological methanation efficiency in Trickle Bed Reactors. The present study, which lies in the field of energy production and biotechnology, entailed the evaluation of commercial pelletized activated carbon and Raschig rings as packing materials. The evaluation focused on monitoring process indicators and examining the composition of the microbial community. Activated carbon resulted in enhanced methane purity, achieving a two-fold higher methane percentage than Raschig rings, maintaining a stable pH level within a range of 7-8 and reducing gas retention time from 6 h to 90 min. Additionally, the digestate derived from biogas plant was found to be a sufficient nutrient source for the process. Fermentative species with genes for β-oxidation, such as Amaricoccus sp. and Caloramator australicus could explain the production of hexanoic and valerate acids during reactor operation. Based on the physical properties of packing materials, the efficiency of biological methanation could be maximized.
Keywords: Activated carbon; Bioprocess optimization; Hydrogenotrophic methanogenesis; Microbial community; Raschig rings.
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