Facilitation of Vectorial Aspects of Methanogenesis in a Shallow Geological Context

Klein, Donald A.¹; Flores, Romeo M.²; Wikramasinghe, Ranil ^3
1 Microbiology, Colorado State Univ, Fort Collins, CO, CO.
² Geology, USGS, Denver, CO.
³ Chem Biol Eng, Colorado State Univ., Fort Collins, CO.

The facilitation of methanogenesis from engineered delivery and extraction systems in shallow geological features analogous to landfills is of increasing interest with respect to energy development and ecological management. When developing hydrogen, carbon dioxide, and methane management strategies, it is critical to consider methanogenesis processes on a micro-site scale in terms of the vectorial aspects of the gas transport. It is particularly important to understand the microenvironment where methanogens and methanogenic consortia act to strip these gaseous resources from their immediate liquid and gaseous physico-chemical environments. A major concern is hydrogen, which is commonly the limiting factor in this process because it only penetrates geological features at low concentrations and flux rates. Thus, hydrogen must be maintained at the maximum possible concentrations and flux rates to allow more efficient methanogenesis to occur.

To facilitate methanogenesis, two strategies are being considered: (1) Sequential Diffusion Methanogenesis Systems, which allow the reactant hydrogen gas to be maintained at higher concentrations and flux rates in geological production features; and (2) the facilitation of hydrogen-surface interactions by use of hydrogen physical traps such as graphite, activated carbon, zeolites, and silicones, as well as aluminum-pillared clays. This process of subsurface hydrogen management is of concern in facilitating use of carbon dioxide that is injected into shallow geological features to allow carbon sequestration, methanogenesis, methane regeneration, and abiotic hydrocarbon formation. By considering hydrogen fluxes and methanogenesis in a designed and engineered microbial ecological system such as a landfill, it is possible to more effectively manage and optimize these shallow biogenic gas-production processes.

AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009