Experimental Study of Biodegradation of Ethanol and Toluene Vapors

oxygen is supplied, the system cannot be operated at steady state under these
conditions.
4. Low dilution rates generate low biomass concentrations because ethanol is
consumed for maintenance requirements.
5.6.2 Theoretical Predictions of Steady State Continuous Removal of Benzyl Alcohol
The relation between the specific growth rate and benzyl alcohol concentration
was given by:
b,max
b
b n
μ (1 − )
(4-3)
= μ
K
b
C
+ C
b
C
C
b,max
The biomass concentration can be predicted by combining
− φ = μC
and
x
x
φ = D( C
0
− Cb ) with Equation (5-32):
b
b
C
x
D( Cb0
− Cb
)
= (5-69)
( μ / Y + m )
xb
b
Using the values of parameters obtained for benzyl alcohol bioremediation listed
in Table 5.2 with the operating conditions of the reactor used in this study
( Q 24L
/ h;
V = R
1.5L)
, benzyl alcohol removal in a CSTR at steady state can be
=
predicted by Equations (4-3) and (5-69) as a function of dilution rate and feed rate.
Results are shown in Figures 5-15a-c. Figure 5-15a reveals that the system can be
maintained at steady state for dilution rates up to 0.25 h
-1 . When the dilution rate is
higher than 0.25 h -1 , the cells are washed out (X=0) and the substrate concentration
reaches the same as the feed (C b = C b0 ). The results also indicate that DO level is higher
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