Anaerobic Digestion Enhancement of Brewery Sludge Assisted by Exogenous Hydrogen

Abstract

The purification of biogas as a product of anaerobic digestion has gradually become a research focus. In situ hydrogen-assisted biogas purification is an effective way to enhance the reaction rate, but the solubility and mass transfer efficiency of hydrogen are the difficulties that constrain the technology. Thus, four continuous hydrogen injection modes M1: 1 mL/min, M2: 2 mL/min, M3: 5 mL/min, and M4: 10 mL/min and two intermittent hydrogen injection modes A: 4 mL/min ( interval 20 min ) and B: 6 mL/min ( interval 40 min ) were designed to explore the effect of different hydrogen injection modes on in situ biogas upgrading of upflow anaerobic sludge bed (UASB) in the research. The results showed that the methane production showed a trend of increasing first and then decreasing in continuous hydrogenation experiment. The CH₄ production reached its peak at 86.2% in the M2 stage. In the two batch hydrogenation tests, group A showed better hydrogenation effect with a CH₄ production of about 92%, which was 4% higher than that of group B. The hydrogenotrophic methanogens (HMs) in group A archaea community were more effectively enriched, with an abundance of 52.83% of Methanobacterium. The results illustrate that proper hydrogen injection can enhance anaerobic digestion and promote biogas purification, and the effect of short-term intermittent hydrogen injection is more significant.