Research

Biogas upgrading and energy storage via electromethanogenesis using intact anaerobic granular sludge as biocathode

Abstract

Microbial electrochemical system is a promising CO2-to-CH4 conversion technology that can upgrade raw biogas to high calorific content for downstream applications. The development of efficient, robust, and cost-effective biocathode is the pivotal issue for its industrial application. In this study, intact anaerobic granular sludge (AGS), which was the conventional biocatalyst in anaerobic digestion processes for high-efficiency CH4 production, was for the first time employed as biocathode in electromethanogenesis system (EM) for biogas upgrading. The applied voltage (0, 3, 4, and 5 V) and biogas flow rate (5.22–23.43 mL/h) were modulated to optimize biogas upgrading performance in the AGS-EM system. The CH4 content in treated biogas could reach as high as 97.9 ± 2.3% at an applied voltage of 4 V and a gas flow rate of 17.79 mL/h. The system showed superior stability and anti-interference ability in the continuous operation mode for 2 months. 16S rRNA sequencing results showed that Methanobacterium and Azoarcus were the dominant populations in biocathode. The AGS-EM system obtained an energy benefit of 477.3 kJ/molbiogas, and economic benefit of 446.4 EUR/m3biogas. The novel AGS-EM system showed the promising perspectives for the industrial application in the field of biogas upgrading and renewable energy storage.

Info

Journal Article, 2020

UN SDG Classification
DK Main Research Area

    Science/Technology

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