Bio-filtration of Organic Pollutants: Simulation and Mathematical Modelling of Toluene and n-propanol

Abstract

Volatile organic compounds (VOCs) are chemical substances that evaporate quickly, releasing harmful fumes into the atmosphere. Among the various VOCs, toluene and n-propanol are particularly interesting due to their widespread occurrence and considerable industrial impact. This study uses a bio-reactor with microbial biofilm formation to present the bio-degradation of a composition of toluene (methylbenzol) and n-propanol (1-propanol). It predicts the coupled inhibition effect of n-propanol on the toluene removal efficiency. The bio-filtration process is modelled as a dynamical system using a set of deterministic nonlinear partial differential equations. The differential equation with its appropriate conditions describes the bio-filtration processes occurring in two distinct phases: the biofilm phase and the gaseous phase. The differential equation is solved using the Chebyshev pseudospectral method and the local linearization method to understand the physical dynamics of the mathematical model. The effectiveness of the spectral-based method was evaluated by comparing its accuracy to known results in the limiting cases of the current dynamical model. A parametric and partial rank correlation coefficient (PRCC) analysis of the dimensionless parameters is conducted. It was found that toluene removal is enhanced by the additional desorption rate constant, ζ2. Increasing the air-biofilm coefficient for n-propanol supports the removal of n-propanol but not that of toluene. The findings of this study contribute to improvements in bio-degradation modelling and enhance our understanding of volatile organic compounds.