Biodegradation of tert-butyl alcohol (TBA) using biological granular activated carbon (bio-GAC)

ABSTRACT Tert-butyl alcohol (TBA), a metabolite of the gasoline additive methyl tert-butyl ether (MTBE), is a common groundwater contaminant encountered at petroleum remediation sites. This work explored the capability of YZ2, a novel pure culture, to completely degrade TBA aerobically in both batch studies and in continuous-flow columns containing biologically activated granular carbon (bio-GAC), simulating an ex-situ remedial system. YZ2 mineralized TBA from 0.5mM to 50mM, which is significantly higher than previously reported cultures. The level at which TBA limited the cellular activity was 40mM; however, mineralization still proceeded up to 50mM. Mineralization experiments showed almost 80% recovery of uniformly radiolabeled TBA as carbon dioxide. YZ2 growth and corresponding TBA oxidation rates within saturated activated carbon were compared with rates quantified in pure aqueous media; results demonstrate that GAC decreases oxidation kinetics for TBA. Batch studies quantified the kinetics of abiotic TBA sorption to activated carbon versus biological TBA oxidation using bio-GAC to compare the rates and efficiencies of physical removal processes to biological strategies. Data demonstrate that adsorption may be more efficient at high TBA concentration. In addition, pH levels increased to as high as 10.2 once activated carbon was added to solutions containing TBA, which inhibited microbial growth. The continuous-flow bio-GAC columns mimicked a field bio-GAC unit and focused on different potential inoculation strategies and the long-term capabilities of YZ2 to degrade TBA as a continuous culture. Current data indicate lower effluent TBA concentrations within the bio-GAC column for 70 days, compared to a sterile GAC control column. However, the overall stoichiometry of the mineralization pathway indicates that dissolved oxygen concentrations in influent water may limit TBA degradation in the bio-GAC column, preventing complete degradation. We are using these data to develop a strategy for biological regeneration of GAC, which may be the most effective use of inoculated, TBA degrading cultures.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Environ Engr in Civil Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2010

Author dc:creator

• Dunnett, Kayleigh A.

Contributors dc:contributor

• Finneran, Kevin T.

• Granular Activated Carbon (GAC)
• Tert-butyl Alcohol (TBA)

Statement dc:rights

• Copyright 2009 Kayleigh A. Dunnett

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/14716

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/14716