The Influence of Environmental Factors on MTBE/TBA Degradationby a Bacterial Consortium: Optimization of an Inoculated Bioreactor

摘要

The use of methyl tertiary-butyl ether (MTBE) in automotive fuel has leadto groundwater contamination plumes that spread relatively quickly and can threatendrinking water wells. At VITO, a mixed bacterial consortium has been isolated fromMTBE-contaminated soil. The VITO M-consortium can reproducibly and rapidly degradeMTBE at initial concentrations relevant for bioremediation (≤ 150 mg/L). Also, theintermediary compounds tertiary-butyl alcohol (TBA), α-hydroxy-isobutyric acid (HIBA)and formaldehyde are completely degraded (≤ 100 mg/L). To address the need for anefficient and cost-effective treatment technology for MTBE-contaminated groundwater,MTBE/TBA degradation and growth by the M-consortium were studied in function ofvarious environmental influence factors in order to optimize bioremediation. The optimaltemperature for MTBE/TBA degradation and growth was 20-29°C. However, at groundwatertemperature and below, MTBE and TBA were completely degraded and significantgrowth of the consortium was measured. Both ammonium and nitrate could be used as anitrogen source for MTBE degradation and biological growth but nitrate was preferred atlimiting concentrations. The presence of the volatile organic aromatic compounds benzene,toluene and meta-xylene (BTmX), in combination with MTBE, increased thegrowth rate of the inoculum without inhibition for MTBE degradation, except for relativelyhigh concentrations of BTmX (> 60 mg/L combined). These results indicate thatthe VITO M-consortium can be used for bioremediation of MTBE, TBA and BTmXcontaminated groundwater.