Figure 6.

The parameter effect on the biofilm thickness. (a) The yield coefficient Y  (MM _n ⁻¹) describes the ratio of the amount of biomass produced to the amount of substrate consumed [25]. (b) The maximum specific growth rate V _T  (M _n M ⁻¹ T ⁻¹) describes the maximum proliferation ability of microorganisms. (c) The diffusion coefficient D  (L ² T ⁻¹) reflects the nutrient diffusion ability into biofilm and (d) the biofilm biomass density ρ  (ML ⁻³) indicates the biomass in unit volume. Moreover, the biofilm thickness as a function of time for different (b) V _T (M _n M ⁻¹ T ⁻¹) and (c) ρ (ML ⁻³) at a steady state (inset) is shown.