Development of renewable energy sources such as ethanol has become a priority
to meet growing energy demands. In the United States, the majority of ethanol is
produced at dry mill facilities that convert corn to ethanol; these facilities can be a major
emission source for volatile organic compounds (VOCs). Biofiltration is a promising
VOC control technology but its effectiveness for the VOC mixtures emitted from ethanol
production facilities has yet to be determined.
The main goal of this research was to evaluate the feasibility of using
biofiltration to treat ethanol plant air pollutants. To accomplish this, microbial
degradation of four representative pollutants (formaldehyde, acetaldehyde, ethanol and
acetic acid) was examined first in simplified batch reactors and then in a laboratory-scale
biofilter system. The batch data indicate that, at a neutral pH, an enriched microbial
consortium was capable of completely degrading formaldehyde, acetaldehyde and
ethanol, and the Monod model was successfully utilized to describe single substrate
degradation kinetics for these pollutants. However, the consortium only partially degraded acetic acid. In binary substrate experiments, acetaldehyde degradation was
not significantly affected by either ethanol or formaldehyde. However, acetaldehyde
inhibition of ethanol degradation was observed and inhibition kinetics were necessary to
describe the observed ethanol removals. Formaldehyde degradation was inhibited in the
presence of acetaldehyde and/or ethanol; however, further research will be required to
identify the inhibtion.
The biofilter study was performed to investigate the effects of pollutant loading,
substrate mixtures and low pH on system performance. The results indicate that it is
feasible to achieve greater than 97% overall removal efficiency at a short contact time of
5 seconds under neutral pH conditions. The level of substrate inhibition observed in the
batch experiments was not evident in the biofilter experiments. However, low pH
conditions gradually decreased the biofilter performance with a more significant impact
on acetaldehyde, a result that was supported by batch data. Finally, a numerical model
that integrated degradation kinetics was able to describe the biofilter performance under
the test conditions. This research demonstrates that biofiltration has the potential to be a
viable VOC treatment technology at corn-derived ethanol production facilities. / text
| Identifer | oai:union.ndltd.org:UTEXAS/oai:repositories.lib.utexas.edu:2152/7569 |
| Date | 02 June 2010 |
| Creators | Chen, Li-Jung |
| Source Sets | University of Texas |
| Language | English |
| Detected Language | English |
| Format | electronic |
| Rights | Copyright is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works. |
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