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Experimental Study of Biodegradation of Ethanol and Toluene Vapors

Experimental Study of Biodegradation of Ethanol and Toluene Vapors

Experimental Study of Biodegradation of Ethanol and Toluene Vapors

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Figure 4-2a shows ethanol liquid concentrations with respect to time at an air<br />

flow rate <strong>of</strong> 2.0 L/min <strong>and</strong> 450 rpm. Figure 4-2 b shows ethanol mass transfer results at<br />

an air flow rate <strong>of</strong> 3.8 L/min <strong>and</strong> 300 rpm. The inlet gas concentration can be obtained<br />

from the slope <strong>of</strong> the straight line, i.e,<br />

V<br />

,<br />

= slope , since the outlet gas<br />

Q<br />

C g in<br />

*<br />

concentration (C gout ) is negligible (less than the detectable limit <strong>of</strong> 0.5 mg/Lair)<br />

compared to the gas inlet concentrations <strong>of</strong> 80.0 - 92.0 mg/L for the cases tested in this<br />

study. The total amount <strong>of</strong> ethanol added into the gas stream was measured to verify the<br />

calculated results <strong>of</strong> ethanol concentrations in gas <strong>and</strong> liquid phases, <strong>and</strong> an error <strong>of</strong> less<br />

than ±5.0% (error = (ethanol mass measured-calculated)/measured mass*100%) was<br />

obtained for ethanol mass transfer experiments.<br />

Results from the ethanol mass transfer study indicated that ethanol liquid<br />

concentrations are limited only by the amount <strong>of</strong> ethanol introduced from the inlet air<br />

stream. Therefore, ethanol mass transfer will not be the rate-limiting step in<br />

bioremediation <strong>of</strong> ethanol from the contaminated air stream.<br />

47

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