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Gewählte Doctoral Thesis:

Peter Freitag (2022): Adapting the Jet Grouting technique for in situ remediation of chlorinated solvent contaminated sites (HaloCrete).
Doctoral Thesis - Institut für Bodenforschung (IBF), BOKU-Universität für Bodenkultur, pp 71. UB BOKU obvsg

Abstract:

This thesis describes the in-situ remediation of sites contaminated with chlorinated solvents, using jet grouting (JG). This geotechnical technique uses a high-pressure jet to erode and mix soil with cement slurry. As fine soil grains are partly washed out during the installation process and the soil loses part of its bearing capacity, the usage of binders such as cements is necessary. The goals of the HaloCrete research project were to investigate the interactions between a reactant (nanoscale zero valent iron), binders and contaminated soil. Batch experiments, aimed at ruling out binders which inhibited dechlorination, acted as a starting point. All chosen binders proved to be feasible choices, and clays were found to catalyse the reaction. It could also be shown that evolving H2 can be used as an indicator for the suitability of a particular binder. Subsequent column experiments simulated the leakage behaviour of JG columns in a groundwater flow. Finally, a large-scale experiment was conducted to demonstrate the practical usability of JG as a remediation technique. Apart from necessary adaptions to machinery, questions such as the stability of the slurry and the distribution of reactant in the cross section of the column were examined. A follow-up project (KOMBO) took place at the site “N65 Putzerei Alaska”. A large investigation campaign and the establishment of a conceptual site model resulted in the selection of JG for the dechlorination of the source zone. Oxidative subsoil conditions required the usage of an oxidant. The execution itself was uncomplicated except for legal restraints and logistics. Hence, not the whole source could be treated. Direct measurements before and after the remediation campaign indicated success. In conclusion, the results show that in situ treatment of contaminated sites using adapted JG proves a feasible possibility. A framework for adaptions was designed which allows future adaption to other contaminants or site conditions.

Betreuer:

1. Berater:

2. Berater: Zechmeister-Boltenstern Sophie