Periodic Reporting for period 1 - CO2FOREARM (Fundamental Study of CO2 Storage through Microbially Enhanced Carbon Mineralization (CO2FOREARM))
Reporting period: 2022-10-01 to 2024-10-31
Large-scale implementation of geological carbon sequestration is considered a key asset to limit anthropogenic warming to 1.5 - 2 °C, as set out in the Paris Agreement. This project focuses on a viable alternative represented by injecting CO2 into reactive rock formations, e.g. basalts, to facilitate rapid carbon mineralization, and therefore increase storage security. The particular interest lies in microbially enhanced carbon mineralization: biological catalysts are utilized to alter reaction rates and further enhance carbon mineralization.
The overarching aim of this project’s research is to provide the fundamental understanding and simulation technology required to assess the large-scale deployment of CO2 storage through microbially enhanced carbon mineralization and hence contribute to climate change mitigation.
Computational studies employ various numerical techniques, combining hybrid-scale modeling and conventional CFD to investigate the flow physics and the complex CO2-rock-biomass interactions at pore and sub-pore levels. Complementary experiments on calcite dissolution are conducted using Atomic Force Microscopy (AFM) imaging aiming at uncovering fundamental processes and embedding these in the modelling framework.
The ultimate aim of the investigations is to use the new experimental and computational data to produce correlations/relationships for use with large scale simulations, as well as developing further fundamental understanding of phenomena of CO2-water-rock-biomass reactive flow in porous media.
As such, the project creates new synergetic knowledge at the interface of biology, geology and numerical modeling, that will inevitably impact traditional subsurface resources other than CO2 storage, e.g. environmental bioremediation and hydrogen storage.
The overarching aim of this project’s research is to provide the fundamental understanding and simulation technology required to assess the large-scale deployment of CO2 storage through microbially enhanced carbon mineralization and hence contribute to climate change mitigation.
Computational studies employ various numerical techniques, combining hybrid-scale modeling and conventional CFD to investigate the flow physics and the complex CO2-rock-biomass interactions at pore and sub-pore levels. Complementary experiments on calcite dissolution are conducted using Atomic Force Microscopy (AFM) imaging aiming at uncovering fundamental processes and embedding these in the modelling framework.
The ultimate aim of the investigations is to use the new experimental and computational data to produce correlations/relationships for use with large scale simulations, as well as developing further fundamental understanding of phenomena of CO2-water-rock-biomass reactive flow in porous media.
As such, the project creates new synergetic knowledge at the interface of biology, geology and numerical modeling, that will inevitably impact traditional subsurface resources other than CO2 storage, e.g. environmental bioremediation and hydrogen storage.
A fully coupled model of fluid flow, reactive transport and biofilm dynamics was developed. The model explicitly accounts for the relevant coupled processes and their interactions with the dynamic porous structure. Modelled processes include advection-diffusion, attachment-detachment of biomass, biofilm growth and spreading, and reactive transport of nutrient. Interactions with the porous microstructure include phenomena of bioclogging and dissolution/precipitation processes. Moreover, the open-source software BioReactPy was released on github, where all the recent methodology and discretization techniques are implemented.
These models were applied first to investigate the coupling between fluid flow and biofilm dynamics at the scale of a single pore and then to the case of subsurface biomineralization relevant to carbon mineral storage. These results show how biological catalysts can enhance carbon mineralization in a very non-linear fashion by bioalkalinization, i.e. the pH increase of the local environment related to the metabolic activities of microorganisms, e.g. by bacterial ureolysis.
In parallel to the biofilm model developments, an innovative reactive transport model tailored to quantitative analysis of dynamics of nano-scale mineral dissolution processes was developed. Highly accurate experimental data obtained through Atomic Force Microscopy (AFM) imaging targeting dissolution experiments (with calcite as mineral of interest) were integrated in the modeling framework. Convergence of the numerical approach was documented (for the first time) down to a sub-nm scale.
The outcomes of the project are four papers published in the most prestigious indexed journals in the field of water science and environmental engineering.
These models were applied first to investigate the coupling between fluid flow and biofilm dynamics at the scale of a single pore and then to the case of subsurface biomineralization relevant to carbon mineral storage. These results show how biological catalysts can enhance carbon mineralization in a very non-linear fashion by bioalkalinization, i.e. the pH increase of the local environment related to the metabolic activities of microorganisms, e.g. by bacterial ureolysis.
In parallel to the biofilm model developments, an innovative reactive transport model tailored to quantitative analysis of dynamics of nano-scale mineral dissolution processes was developed. Highly accurate experimental data obtained through Atomic Force Microscopy (AFM) imaging targeting dissolution experiments (with calcite as mineral of interest) were integrated in the modeling framework. Convergence of the numerical approach was documented (for the first time) down to a sub-nm scale.
The outcomes of the project are four papers published in the most prestigious indexed journals in the field of water science and environmental engineering.
The project has led to three key scientific results: (i) development of a new pore-scale simulation model for coupled flow, biofilm growth and reactive transport through porous media; (ii) identification of biofilm growth mechanisms and characterization of biomass-flow systems through a new dimensionless quantity; and (iii) development and validation (through comparison with experimental observations) of an original reactive transport model tailored to the analysis of the dynamics of nano-scale mineral dissolution processes. Moreover, open-source software tools for simulation of microbial-mediated reactive processes in porous media were developed.
The project has substantially contributed to taking the understanding of biogeochemical reactive processes in the subsurface largely beyond the state of the art. The developed multiphysics models can be readily exploited to investigate the complex process-structure interactions typical of the reactive subsurface environment. Findings stemming from the integration of numerical modelling and experimental observations of nano-scale mineral dissolution are a key milestone towards understanding the mechanisms underpinning chemical weathering of minerals across diverse spatial and temporal scales. The open-source software and the open science policies implemented will allow other researchers to use the approaches and results of CO2FOREARM to answer other engineering and mathematical questions arising in the subsurface, as well as to validate simulations models, further build up new methodology and/or develop benchmark test cases.
The project has substantially contributed to taking the understanding of biogeochemical reactive processes in the subsurface largely beyond the state of the art. The developed multiphysics models can be readily exploited to investigate the complex process-structure interactions typical of the reactive subsurface environment. Findings stemming from the integration of numerical modelling and experimental observations of nano-scale mineral dissolution are a key milestone towards understanding the mechanisms underpinning chemical weathering of minerals across diverse spatial and temporal scales. The open-source software and the open science policies implemented will allow other researchers to use the approaches and results of CO2FOREARM to answer other engineering and mathematical questions arising in the subsurface, as well as to validate simulations models, further build up new methodology and/or develop benchmark test cases.