In-Situ Biogas Upgrading with Pulse H2 Additions: Microbial Adaptation and Reactor Performance of Anaerobic Digestion

Renewable power sources such as wind and solar energy are expected to cover a significant fraction of future electricity demands, but their fluctuating nature presents a growing need to store surplus electricity. A potential energy storage mechanism is the injection of surplus electricity in the form of H2 gas in anaerobic digesters, where the inherent microbial community readily converts it to CH4. The response of the microbial community and reactor performance to intermittent periods of high and low H2 concentrations was assessed to evaluate the potential of this energy storage mechanism. The reactor performance and conditioning of hydrogenotrophic methanogen populations during intermittent pulse H2 injections was assessed in mixed-culture lab reactors.