A mathematical model was developed to
describe the reduction of Cr(VI) by
Escherichia coli
(
E. coli) 33456 in a fixed biofilm reactor. A laboratoryscale
column reactor was conducted to verify the model
system. The batch kinetic tests were independently conducted
to determine the biokinetic parameters used in the
model simulation. With the assumed values of initial biofilm
thickness (
Lf0), the mathematical model simulated
well the experimental results for Cr(VI) effluent concentration,
effluent concentration of suspended
E. coli cells,
and Cr(III) production. The concentration of suspended
E. coli cells reached up to 1.2 mg cell/L while the thickness
of attached
E. coli cells was estimated to be 32.6 μm
at a steady-state condition. At the steady state, the removal
efficiency of Cr(VI) was about 92 % and the effluent
concentration of Cr(III) was approximately 1.6 mg/L. The
approaches presented in this study can be employed for the
design of a pilot-scale or full-scale fixed biofilm reactor to
treat Cr(VI)-containing wastewater.
