A wastewater stream containing phenol (component A) is treated in the bioreactor. In the rotating discs in the tank serve as a support for microorganisms that possess enzymes capable of degrading phenol into less hazardous compounds degrade phenol into compounds of lower health risk. The rate of phenol degradation per unit volume of biofilm can be described by:

(maximum degradation speed)

(Average saturation constant)

Consider

= 2.0 10^-10 m² / s

C_a,0 = 0.1 mol/m³

At low solute concentrations the rate law can be approximated to first order kinetics with 1 = ,/. It is desired to treat 0.1 m³/h of wastewater, if the thickness of the biofilm is 2.00 10^-3 m, what is the surface area of the biofilm needed to decrease the phenol concentration in the outflow stream to. 0.02 mol/m³ ?

Ans = 57 m²

-RA= RA,maxCA KA + CA RA,max = 5.7 x 10-3 mol/m s 3 S KA = 0.3 mol/m Cao S z = 0 2 = 8