%0 Journal Article
%T Enhancing H2-driven CO2 biomethanation performance in bidirectional flow tidal bioreactor by reducing liquid film resistance and heterogeneity.
%A Zhang J
%A Xu H
%A Zhang X
%A Xiang Y
%A Li S
%A Holmes DE
%J Bioresour Technol
%V 409
%N 0
%D 2024 Oct 8
%M 39122127
%F 11.889
%R 10.1016/j.biortech.2024.131247
%X This study presents a bidirectional flow tidal bioreactor designed to enhance H2-driven CO2 biomethanation. The bioreactor alternated biofilms between immersion in nutrient solution and exposure to H2/CO2, creating alternating dry and wet states. This tidal operation minimized liquid film thickness during dry periods and ensured uniform nutrient distribution during wet periods. Bidirectional H2/CO2 supply was used to reduce biofilm thickness heterogeneity across the reactor height. CO2 biomethanation remained stable with an empty bed residence time of 9.7 min, achieving a methane (CH4) formation rate of 26.8 Nm3 CH4/(m3·d). The product gas contained 95.0 ± 2.5 % CH4, with a H2/CO2 conversion efficiency of 90.8 %. Tidal operation mitigated the buildup of dissolved and suspended organics, such as organic acids and detached biofilms. Dominant bacteria in biofilms included fermentative species like Petrimonas and H2-utilizing homoacetogens like Sporomusa. Enriched hydrogenotrophic methanogens, particularly Methanobacterium, were observed. Overall, this study highlights the bioreactor's effectiveness in improving CO2 biomethanation.