Bioprocess Engineering 2nd Edition by Fikret Kargi,Michael Shuler

Exercise 4

An industrial waste-water stream is fed to a stirred-tank reactor continuously and the cells are
recycled back to the reactor from the bottom of the sedimentation tank placed after the reactor. The following are given for the system:
F = 100 l/h; S0 = 5000 mg/l; mm = 0.25 h-1; Ks = 200 mg/l; a (recycle ratio) = 0.6; C (cell concentration factor) = 2; YX/S M = 0.4. The effluent concentration is desired to be 100 mg/l.
a. Determine the required reactor volume.
b. Determine the cell concentration in the reactor and in the recycle stream.
c. If the residence time is 2 h in the sedimentation tank, determine the volume of the sedimentation tank and cell concentration in the effluent of the sedimentation tank.