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unilogo Universität Stuttgart
Institute of Hydraulic Engineering

Research: VEGAS - Research Facility for Subsurface Remediation

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Project network "Application of microemulsion at the in situ remediation of organic underground contamination"
Project 4: Large-scale experiments for the development and the optimization of hydraulic remediation thechniques using a microemulsion
Project manager:PD Dr.-Ing. Baldur Barczewski
Research assistants:Dr. rer.nat. Matthias Stuhrmann
Duration:1.6.2001 - 31.5.2005
Funding:Federal Ministry of Education and Research
Project Partners:Forschungszentrum Jülich (FZJ), Jülich
DVGW-Technologiezentrum Wasser (TZW), Karlsruhe
IMB Umwelt- und Biotechnik GmbH, Heidelberg
Comments:

This project is part of the research area:
In-Situ Remediation Technologies

Publications: Link

Abstract:

On different scales, from the range of the laboratory up to pilot plant station tests, the partners of the project network performed experiments, in which the microemulsion applied (anionic and non-ionic surfactant, rape oil methyl ester (RME), brine, water) showed a high solubilization and extraction capacity of Tetrachlorethen (Perchloroethylene, PER) present in the water saturated zone in the underground.

There is only a limited comparability of the flow behaviour of the microemulsion and the uptake of pollutants at small-scale experiments with the results from experiments on the scale of several cubic meters. Because of the dispersion of the microemulsion intensified there, a not sufficient discharge of pollutant and microemulsion components resulted in the field experiment due to the scarcely measured quantity of microemulsion. The crucial clue to the flow behaviour of the microemulsion and to the pollutant admission in the underground resulted in a successful large-scale experiment, with which more than 90 % of the pollutant PER from an artificial groundwater aquifer were removed.

Further the results of the experiments demonstrate the good degradability of RME and of the nonionic surfactant. Under aerobic conditions the anionic surfactant clearly showed more than only primary degradation. The co-metabolic degradation of RME in presence of microemulsion components could be shown. A disturbance of the pollutant extraction by micro-biological processes wasn't observed in any experiment. Thus a complete remediation of a contaminated site is possible by a biological subsequent treatment after extraction.

The process steps for the treatment of the flushing solution and for the recovery of the microemulsion components require an only relatively small effort. In the context of the field experiment further the necessary techniques developed for the setting up, quality control, storage, handling and infiltration of the microemulsion were successfully tested under field conditions. Altogether it could be proven that in principle the whole process from making the microemulsion up to its regeneration can be performed successfully in a large scale.