6.6. In a trickling biological filter, the BOD value of the feed stream is S0i=500mg/l with a feed flow of F=103l/h. The effluent BOD value is desired to be S0=10mg/l. The following kinetic parameters for the biocatalysts are known: rm=20mg/S/lh and Ks=200mg S/l. The biofilm thickness is L=0.1mm. The cross-sectional area of the filter is A=2m2, and the biofilm surface area per unit volume of the bed is a=500cm2/cm3. Assume that dissolved oxygen is the rate-limiting substrate and the diffusion coefficient of oxygen is DO2=2105cm2/s. Determine the required height of the bed. You can assume first-order bioreaction kinetics