Macro‐scale modelling of substrate removal kinetics in multicomponent fixed‐film systems

Design of aerobic fixed‐film systems is generally performed using a traditional chemical reactor theory which accounts for changes in both substrate and biomass concentration. As most of these systems do not behave as ideal reactors, the theoretical evidence clearly shows that the variation and impact of biomass cannot be accounted for by a single reactor concept. Refinements reported in the literature concerning the fate of soluble substrate are modified in this study to also include the variation of biomass viability for different substrate concentration along the aerobic reactor. Evaluations show that a multi‐stage modelling biofilm performance is likely to be a much more reliable predictive tool for removal efficiencies.