A bio film reactor with a well-mixed liquid phase shown below will be used to treat wastewater contaminated with trichioroethylene (TCE) at a concentration 0.25 mg/L (1.9 mmole/m³, M_TCE = 131.4 g/gmole). If the available surface area of the bio film in the reactor is 800 m², and the volumetric flow rate of wastewater into the reactor is 100 m³/h, what is the desired outlet concentration of TCE? The temperature of the process is constant at 20^oC. In a well-mixed, continuous-flow reactor at steady state, the concentration of the solute of the liquid phase of inside the reactor is assumed equal to the concentration of the solute in the liquid that exits the reactor. It may also be assumed that the TCE degradation in the bio film proceeds by homogeneous first-order reaction kinetics. The bio film is of δ = 100 µm thickness.

Potentially useful data*: k_TCE = 4.3 1 s^-1 (first-order rate constant for TCE in biofilm); D_TCE-biofilm = 9.03 × 10^-10 m²/s (diffusion coefficient TCE in bio film).