Experimental Study of Biodegradation of Ethanol and Toluene Vapors

operation could not reach steady state. At the dilution rate of 0.027 h -1 , biomass
concentrations declined, which in turn caused toluene gas outlet concentrations to
increase. Both cases failed to reach steady state operation. Figure 4-14 shows the results
of toluene removal at a toluene gas inlet concentration of 11.0 mg/L and at dilution rates
of 0.027 and 0.005 h -1 . Under both conditions, 70% of the inlet toluene bypassed the
reactor through gas phase, and benzyl alcohol accumulated in the liquid phase with
concentrations up to 0.4 g/L. Under all the above conditions, toluene concentrations in
the outlet gas consistently increased with respect to time while benzyl alcohol
accumulated in the liquid phase, which in turn failed to reach steady state. It was
concluded that toluene, as the sole carbon source, could not be effectively utilized by
Pseudomonas putida, and thus only bioremediation of the mixtures of co-substrates and
toluene were further investigated.
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