| dc.description.abstract |
<p>Volatile organic compounds (VOCs) are a family of chemicals which are known to
have adverse effects on climate change and health, and thus emissions of VOCs are
regulated. One such control method is via biodegradation in a biofilter and other
similar reactors. Many hydrophobic VOCs, however, are difficult to degrade in such
devices. Biphasic bioreactors are designed to remove and treat hydrophobic compounds
from waste gas streams. In addition to the water phase, a biphasic bioreactor includes
a secondary (2°) liquid phase where hydrophobic VOCs are absorbed and made available
for degradation by bacteria. A viable 2° phase is non-miscible with water, non-toxic
to bacteria in the bioreactor, and has a strong affinity for target pollutants. In
this work, methods were explored by which candidate 2° phases may be screened for
suitability to treat two commonly studied hydrophobic VOCs, toluene and hexane. 2°
phases included the commonly used silicone oil, paraffin oil and several ionic liquids
(ILs), a novel type of solvent popular with the chemical industry. The air-liquid
partition coefficient of toluene and hexane with each 2° phases was determined. Additionally
the effect on the oxygen uptake rate (OUR) and cell growth in a flask of each 2° phase
on biological cultures enriched on toluene and hexane was studied. It was determined
that OUR is a poor method of screening 2° phases for biophasic bioreactors. Additionally,
cell growth studies failed to capture accelerated degradation of the target pollutants
in biphasic cultures. The presence of ILs resulted in significant biological inhibition,
and thus do not appear to be promising 2° phase candidates for biodegradation purposes.</p>
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