Experimental Study of Biodegradation of Ethanol and Toluene Vapors

negligible
( y out , e
= 0)
, and ethanol was introduced into the reactor from a gas stream,
not by a liquid stream
( C
e, 0
= 0) , and D
V
F = , then:
e
Q(
yin
− yout
) F(
Ce0 − Ce
) Q
φ
e
= +
= yin,
e
− DC , (5-49a)
V
V V
Considering that toluene was also introduced into the reactor by a gas stream and not a
liquid stream ( C T 0
= 0 ), then:
Q(
yin,
T
− yout,
T
) F(
CT
0
− CT
) Q
φ
T
= +
= ( yin,
t
− yout,
t
) − DCT
(5-49b)
V
V V
Combing Equations (5-49), (5-49a) and (5-49b):
C
x
(
1 Q
max Q
max
= ⋅{(
yin, e
− DCe
) ⋅Yex
+ [ ( yin,
t
− yout,
e
) − DCt
] ⋅Ytx
}
μ + met
) V
V
(5-71)
Equations (5-70) and (5-71) are applied to predict ethanol, and biomass concentrations
during the steady state continuous removal of ethanol and toluene mixtures in a CSTR.
The prediction results are shown in Figures 5-16 to 5-18.
Figure 5-16 shows biomass (X) and ethanol (C e ) concentrations and DO levels
(calculated from Equation 5-68) for removal of ethanol/toluene mixture at toluene gas
inlet concentration of 5 mg/L. The results show that with a constant toluene inlet
concentration of 5 mg/L, the biomass concentration decreases with increase of dilution
rates. When the dilution rate approaches 0.12 h -1 , the dissolved oxygen concentration
drops below the critical oxygen concentration for the growth of bacteria (0.35 mg/L).
Thus the bacteria will no longer grow, i.e. μ