Experimental Study of Biodegradation of Ethanol and Toluene Vapors

concentration reaches the value such that all of the ethanol from the gas steam is
dissolved in the liquid. Toluene in the liquid phase is at equilibrium with the inlet
toluene gas. Toluene in the exit gas stream equals the inlet gas concentration because no
consumption happens after cells are washed out. Thus, when the system is operating
with a dilution rate above 0.12 h -1 , oxygen mass transfer becomes a rate-limiting factor
at these conditions.
Biomass Concentrations, g/L
2.5
2
1.5
1
0.5
0
DO
X
Ce
0
0 0.05 0.1 0.15 0.2
Dilution rate, h -1
8
7
6
5
4
3
2
1
Ethanol concentration (g/L), DO
(mg/L)
Figure 5-16. Continuous removal of ethanol and toluene
(C g,e = 0.082 D(V/Q); y t,in = 5 mg/L)
142