Self-fluidized GAC-amended UASB reactor for enhanced methane production

Anaerobic digestion is achieved through cooperation among various types of microorganisms, and the regulation of microbial communities is key to achieving stable system operation. In this study, the r/K selection theory was adopted to examine the system performance and microbial characteristics in anaerobic reactors with different operating modes (continuous-flow reactors, CFRs; sequencing batch reactors, SBRs) and sludge retention times (25 and 10 days). Four lab-scale reactors (CFR25d, CFR10d, SBR25d, and SBR10d) were operated. In the cycle reaction, CFR25d achieved the highest methane yield (678.0 mL/L) and methane production rate (140.8 mL/(L·h)); while those in CFR10d were the lowest, which could have been due to an accumulation of volatile fatty acids. CFR could wash out r-strategists efficiently, such as Methanosarcina. CFR25d and CFR10d significantly enriched the K-strategist Geobacter, with the relative abundances of 34.0% and 72.6%, respectively. In addition, the hydrogenotrophic methanogens of Methanolinea and Methanospirillum (K-strategists) dominated in CFR25d and CFR10d. Methanobacterium adapted to the diverse operational conditions, but the slow grower Methanosaeta only accounted for 0.9% in CFR10d. Failure to enrich propionate oxidizers resulted in a functional absence of propionate degradation in the CFRs.

Methanosaeta

Methanobacterium

Geobacter

Sequencing batch reactor

10.1016/j.scitotenv.2021.150732

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Citations (26)

Changes in microbial community associated with dechlorination of leftover chloroform in two-stage anaerobic Co-fermentation (H2+CH4) of lipid-extracted microalgae waste with food waste leachate

International Journal of Hydrogen Energy (2018)

Dong‐Hoon Kim Seoktae Kang Yeo‐Myeong Yun

Methanosaeta

Methanobacterium