FIG. 6.

Steady-state concentration profiles of O₂, NH₄⁺, NO₂⁻, NO₃⁻, H₂S, and pH in the aerobic wastewater biofilm incubated in DO-controlled (DO = approximately 70 μM) medium with 600 μM Na-propionate, 550 μM NH₄⁺, 270 μM NO₃⁻, 300 μM SO₄²⁻, and 100 μM NO₂⁻ (A) and the spatial distribution of the estimated specific consumption and production rates of O₂, NO₃⁻, and H₂S (B). The points are measured mean values of measurements in triplicate. The solid lines are the best fits from the model to calculate the specific consumption and production rates of O₂, NO₃⁻, and H₂S. The biofilm surface is at a depth of 0 μm. R, rate.