Dynamic mathematical model for biotransformation and mass transfer of livestock generated voc‐odor in a bioactive dust particle system

Abstract

A multi‐step mass transfer‐biodegradation model is developed to describe the bioactive adsorber dynamics for the biotreatment of livestock generated odor causing VOCs (VOC‐odor) based on a biologically active dust particle (BADP) proc ess. The BADP process employs dust particles with adsorbat‐acclimated microbial culture to form the bioactivated dust particles (BDP) for the simultaneously adsorption, mass transfer, and biodegradation of VOC‐odor. The model incorporating age and size distributions of BDP considers the equilibrium partitioning of VOC‐odor at BDP and bulk gas interface that followed by two kinetic processes occurring in the bulk and solid phases: bulk gas mass transfer‐biodegradation and BDP biofilm diffusion‐biodégradation. Analytical equations indicate that the overall biotransformation rate of VOC‐odor in a BADP process is controlled by BDP‐bulk gas equilibrium processes represented by the slowest of two kinetic processes determined by a dimensionless group: the Thiele modulus (²), the Damkohler number (Da) and the Biot number (Bi). Computer simulations demonstrate that the most favorable performance of a BADP system in reducing VOC‐odor concentrations is operated under Bi<\, Da<1, or Bi > 1 <² < 1; indicating diffusion‐biodegradation controlled. The dimensionless group can be used to identify the dominant rate‐limiting processes and to evaluate the overall biomineralization rate in a BADP process. Simulation results allow the determination of preliminary design for prototype development.

Key words:

• Biofilm
• biodegradation
• dust particle
• mass transfer
• odor
• VOC