Experimental Study of Biodegradation of Ethanol and Toluene Vapors

Equations (5-34) and (5-35) and the values of parameters in Table 5-1 are applied in the
prediction of batch growth on ethanol.
r
x
μe,maxCe
= μ C
x
= C
x
(5-34)
K + C
e
e
dC
1
μ
C
e
e,max
e
− = ( )( )
max
dt Yxe
K
e
+ Ce
C
x
+ m C
e
x
(5-35)
Figure 5-11(a) illustrates the typical profiles of ethanol (S (g/L) =23.02(g/Cmol)*C
e (C-mol/L)) and biomass mass concentrations (X(g/L) = 22.6 (g/C-mol)*C x (Cmol/L))
during batch growth at different ethanol initial concentrations. The results show
that after a “lag phase” (caused by the initial low concentration of biomass) of about 5
hours, there is a long exponential growth phase (log phase) where the biomass
concentration increases exponentially with time. At the end, where the substrate is
consumed completely, growth stops. This is a typical behaviour when the growth
follows Monod kinetics.
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