Research project METLEN

Methyl-tertiary-butyl ether (MTBE) - Leuna as a Reference test site for the implementation of the enhanced natural attenuation approach, Subproject 2: Anaerobic and chemically induced degradation of MTBE

Partners:  (all GER)
- Centre for Environmental Research Leipzig (UFZ)
- Chair of Applied Geology at the University of Kiel
- Chair of Applied Geology at the University of Tübingen

Funding:  Federal Ministry of Education and Research (BMBF)

Duration:  September 2002 - February 2007

Contact:  Dr. Axel Fischer

The BMBF project "METLEN" is the abbreviation for:  METhyl tertiary butyl ether - Leuna as a reference site for implementing the "enhanced natural attenuation" approach. The gasoline additive methyl tertiary butyl ether (abbreviation: MTBE) has been added to gasoline worldwide for about 20 years to improve combustion properties. For some years now, MTBE has been found in ground and surface waters, especially in the USA, but increasingly also in Germany and Europe.

MTBE is toxic and difficult to break down. MTBE was produced in Leuna for many years. Ground and surface water in Leuna is highly contaminated with MTBE (up to more than 60 milligrams per liter).

In the METLEN joint project, the Chair of Contaminated Sites at the TU Dresden, the Environmental Research Center Leipzig (UFZ) and the Universities of Kiel and Tübingen are conducting on-site research in Leuna to find ways of enhancing the natural degradation processes ("enhanced natural attenuation") in the groundwater. To this end, a flume structure was designed that can be used to test the transferability of laboratory results to the field scale.

The TU Dresden is investigating two degradation pathways. One is anaerobic biodegradation and the other is the chemical/catalytic decomposition of MTBE.

Initial tests in the area of anaerobic, microbial degradation of MTBE confirmed a very low degradation potential. All BTEX compounds initially contained in the samples could no longer be detected within a short period of time.

For the study of chemical/catalytic degradation, the acid instability of MTBE plays an important role. For example, the clay mineral montmorillonite showed potential with respect to the transformation of MTBE. Upon contact with water, a pH value of 2.3 is reached. Within the test series, tertiary butanol (TBA) could be detected as a degradation product (see diagram).

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