Experimental Study of Biodegradation of Ethanol and Toluene Vapors

where k L a is the volumetric mass transfer coefficient for toluene, S t * is the liquid
equilibrium concentration ( S
*
t
=
C
g
H
, i.e., the maximum solubility in water at
experimental conditions, 530 mg/L, from Lyman et al., 1982), S t is the liquid
concentration of toluene at any particular time, t. The integration of Equation (4-1)
gives:
*
( St
− S0
)
ln[ ] = kla
⋅t
*
( S − S )
t
t
(4-2)
Once the liquid toluene concentrations with respect to time have been measured, the
volumetric mass transfer coefficient, k L a, can then be determined by plotting
*
( St
− S
ln[
*
( S − S
t
0
t
)
]
)
versus time (t). The slope of the straight line is the volumetric mass
transfer coefficient, k L a. At an air flow rate of 2.0 L/min and toluene inlet concentration
of 105 mg/L, the k L a values for toluene (See Figure 4-1) were found to be 8.3x10 -4 ,
8.8x10 -4 , and 1.0x10 -3 s -1 at agitation speeds of 300, 450 and 600 RPM, respectively.
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