Steady-state model for ammonia removal from swine facility air with a cross-flow biotrickling filter: model development and sensitivity analysis
Authors: Martel, M, S Lemay, B Predicala, M Girard, M Belzile, J Feddes, S Godbout
Description: Biological methods have been found more economical and efficient in treating large volume but less concentrated waste gases such as those emitted from swine production. Yet, despite their advantages, they are limited by some operational problems. Nevertheless, the use of mathematical models helps reduce the impact of these limitations since models can be used not only to describe and predict process performance but also to identify relevant parameters for a better design and process optimization. Thus, a steady-state model was developed to describe the removal of ammonia from pig house exhaust air in a cross-flow biotrickling filter. The model takes into account the transfer of ammonia from the air to the trickling liquid, the diffusion from the liquid phase to the biofilm, and the degradation in the biofilm by the immobilized microorganisms. Mass balance equations in the gas, liquid, and biofilm phases of the treatment system were formulated to describe these processes. The derived differential equations were solved using finite difference method and a computer code was written in Visual Basics for Applications (VBA). A one-at-a-time sensitivity analysis showed that the mass transfer coefficient and the fraction of the wetted surface area of the packing media strongly affect the removal of ammonia. These results can then be used to improve the design and operations of the biotrickling filters in removing ammonia from waste air.
Keywords: mathematical modelling, model development, sensitivity analysis, biotrickling filter, ammonia removal, swine facility air
Technical field: technical_fields_app1
Session name: Biological systems