Experimental Study of Biodegradation of Ethanol and Toluene Vapors

Table 4-2. Comparison of bioremediation of air streams contaminated with ethanol
using a CSTR against using a biofilter
Pollutant Inlet Conc.& Loading Removal Efficiency
(g/m3, g/m3-h)
Ethanol 1 1.89, 120 89%
Ethanol 2 3.0, 90 100%
Ethanol 2 10.0, 300 68%
Ethanol 19.5, 304 100% (this work)
1. Kiared et al., 1996.
2. Arulneyam et al., 2000.
4.4.2 Toluene Bioremediation
The bioremediation of toluene as the sole carbon source in the contaminated air
was attempted in continuous mode. Different conditions were studied by varying the
dilution rates from 0.01 to 0.1 h -1 , the toluene air inlet concentrations from 4.5 to 23.0
mg/L and air flow rates of 0.25 to 0.37 L/min (resulting in inlet toluene loadings from
70 to 386 mg/L-h). At toluene inlet concentration of 4.5 mg/L, it was observed that 96
% of the inlet toluene was initially captured within the liquid phase. However, toluene
concentration in the liquid phase steadily increased to 30 mg/L over a 30 minute
interval, resulting in the complete inhibition of Pseudomonas putida with no biomass
growth. Figures 4-13 and 4-14 demonstrate the results at toluene inlet concentrations of
23.0 and 11.0 mg/L, respectively.
Figure 4-13 illustrates continuous removal of toluene at a gas inlet concentration
of 23.0 mg/L and dilution rates of 0.01 and 0.027 h -1 . As shown in Figure 4-13 at
dilution rate of 0.01 h -1 , biomass could use toluene as carbon source for growth, but the
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