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

摘要

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