Experimental Study of Biodegradation of Ethanol and Toluene Vapors

Figures 5.5 (a-d) demonstrate the simulation results using the optimum
parameters in Table 5.2 for benzyl alcohol bioremediation. The parity plots presented in
Figures 5.6 (a-b) compare the simulation results with the batch experimental results of
benzyl alcohol bioremediation at different initial benzyl alcohol concentrations. The
dash lines in Figures 5.6a and 5.6b present 95% confidence interval: error = ±
t
N
* s
0.025,
(Kennedy and Neville, 1974), where
t 0.025,30
=2.042, s is the standard error: for biomass
sx =0.0019 , for benzyl alcohol s b =0.0031. The results reveal that most of the predicted
values for both biomass and benzyl alcohol fall within 95% confidence level.
Figure 5-6c shows the determination of the specific growth rates of
Pseudomonas putida (ATCC 23973) on benzyl alcohol by plotting ln (X) versus time
for the batch runs. The slopes of the straight lines determined as such are shown on the
graph, which indicates that benzyl alcohol inhibits the growth of P. putida. The μ max
value was found to be 0.41h -1 using Equation (4-10), which agrees with the result
obtained by using non-linear fitting (see Table 5.2). From the comparison of the
simulated results and the experimental results, the simulation models for both ethanol
and benzyl alcohol bioremediation are capable of accurately predicting the growth data.
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