High-resolution Simulation of Denitrification
Abstract
Denitrification is a process where bacteria use nitrate as electron acceptor in the absence of oxygen. It is a potential source of nitrous oxide, an important greenhouse gas. It has been shown experimentally that denitrification is also occurring in well aerated soils. The common assumption is that anoxic zones are located within dense aggregates in a heterogeneous soil. To test this theory, laboratory experiments with an ensemble of artificial aggregates from sintered glass were conducted. The aggregates were inoculated with bacteria from two strains capable of denitrification up to different terminal products. Mathematically, denitrification can be modelled as as a reaction-diffusion process in a complex pore geometry. To evaluate the experiments, simulations of microbial growth and sustenance in the aggregates were conducted using high-resolution pore space geometries obtained from X-ray micro-tomography. A new model for denitrification consisting of a system of nine coupled reaction-diffusion equations was developed. It is solved numerically on a parallel computer cluster. The computational efficiency of the approach is evaluated and the influence of microbiological parameters (Michaelis-Menten constants) is tested and the parameters are compared and adapted according to experimental data.
- Publication:
-
EGU General Assembly Conference Abstracts
- Pub Date:
- April 2018
- Bibcode:
- 2018EGUGA..2015156Z