Engineering Design of Pilot Biofilters for Ventilation Air Methane Abatement Via Biological Oxidation

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Commodities

Practices

• Natural Resources/Environment: other
• Production Systems: holistic management

Agriculture contributes about 18% of all greenhouse gases (GHG) global emissions and 10% of US emissions. Dairy farms are an important source of GHG emissions including enteric fermentation, manure management, and soil management. Methane (CH₄) from enteric fermentation is the largest source of emissions with about 45% of the total GHG emissions of the full dairy farm system. Most of the efforts for the abatement of CH₄ emissions focus on sources with high concentration of CH₄. However, combustion for energy recovery is not feasible in enclosed agricultural systems due to the low concentration of CH₄ in those emissions. Engineered biofiltration technology is a potential solution for the mitigation of emissions converting CH₄ into carbon dioxide (CO₂) and water. The objective of this work is to design a pilot-scale biofiltration system for the mitigation of CH₄ emissions from dairy livestock facilities ventilation air. I will build a bank of six biofilters to study the effect of process conditions on biofilter performance. CH₄ concentration and CO₂ production will be measured in the inlet and outlet of the system to calculate the CH₄ elimination capacity as performance criteria of the system. Experimental data will be gathered at different process conditions for the calibration and validation of a mechanistic mathematical model that is being simultaneously developed. Both the experimental analysis and the model validation will serve as tools to propose engineered microbial biofiltration technology suitable to be implemented in dairy farms, contributing to more sustainable agricultural practices.

The overarching goal of this proposal is to design and test a microbial biofiltration system for the biological oxidation of CH₄-contaminated air from ventilation air of dairy livestock facilities. I propose an experimental approach to investigate the effect of process conditions on the biofiltration system performance. In addition, I propose to use the experimental data as an input to a mechanistic process model, that I am currently developing as part of my dissertation, to elucidate the relationships between process conditions with the mass transfer phenomena and the biodegradation kinetics of the system. I will pursue the following research objectives:

Objective 1. Demonstrate the feasibility of pilot-scale biofilters to biologically oxidize low concentration CH₄.

Objective 2. Investigate the effect of different operation conditions on the CH₄ biofilter performance.

Objective 3. Identify the correlations among the operation conditions and the mass transfer and biodegradation kinetics of the system.

Objective 1 includes the design and building of a pilot-scale biofiltration system. The biofilter performance will be assessed by quantifying the elimination capacity of CH₄. In objective 2, I will evaluate the effect of CH₄ inlet concentration and inlet air flow rate on the CH₄ oxidation capacity of the system since those variables are known to have an influence on the CH₄ oxidation²⁰. To evaluate the effect of process conditions on the mass transfer and biodegradation kinetics of the process in Objective 3, I will use the gathered experimental data from Objective 2 as the input for a mechanistic mathematical model of the system that I am currently developing as part of my dissertation. In that way, mass transfer and biodegradation parameters will be identified as a function of the process conditions and correlations could be established.