Meso-scale pressure reactor demonstrates biostimulation of coal-dependent methanogenesis

In this study, a large high-pressure reactor was used for the first time to investigate microalgae amendments in microbially-enhanced coal bed methane (MECBM) production. A block of coal collected in the Powder River Basin (PRB, Montana, USA) was incubated at in situ pressures in a 325 L reactor. A mechanical packer inserted into a borehole drilled in the coal within the reactor allowed for coalbed methane water injection, inoculation with a methanogenic consortium from a PRB coal seam, and amendment with 13C-labeled microalgae biomass to track MECBM. Results indicated that microalgae stimulates coal-dependent methanogenesis early on, and boosts the coal-derived methane production in the long run. This first scale-up laboratory experiment is paving the way for future field-scale demonstrations of MECBM and advancing laboratory-based investigations of subsurface biotechnologies.