Protection of Groundwater Resources at Industrially Contaminated Sites (PURE)
The research project PURE (Protection of Groundwater Resources at Industrially Contaminated Sites) was funded by the European Commission within the Fifth Framework Programme. The objective of the project was to provide innovative/cost effective solutions for the management of industrially contaminated sites in terms of the site characterization, site assessment and site remediation.
Within the PURE research project an in-situ technology for the simultaneous remediation of contaminant source zones in the saturated and unsaturated zones was to be developed. Two existent remediation technologies: co-solvent flooding (CSF) and thermally enhanced soil vapour extraction (TSVE) were combined. The research work was based on site-specific soil and groundwater contaminations of two industrial project partners.
The combined technology was developed and tested in a large VEGAS container (70 m³) under quasi realistic site conditions. The container was filled with soil from a site of the project partners and polluted with a contaminant mixture comparable to the contamination at the site.
During the SubTSVE remediation experiment a steam-air mixture was injected into the saturated zone resulting in a highly efficient, controllable and save removal of the contamination located in the saturated and unsaturated zone.
The propagation of the heat front and the remediation time were calculated by simplified analytical methods and confirmed by the experimental approach. A combined CSF-SubTSVE remediation experiment resulted in a total removal rate of more than 96 %. A CSF remediation experiment of the saturated zone was designed by numerical means to provide a sufficient flooding of the contaminant source zone. Approx. 88 % of the initial contaminant mass was extracted. The used isopropanol was completely recovered.
Based on the data and experience gained during the technical scale experiment a full scale remediation for one industrial site was designed. The design included time, setup and operation of technology-specific treatment units and financial aspects. In cooperation with a service provider the costs for the application of SubTSVE were compared to those of the combined standard remediation techniques Air-Sparging and Soil Vapour Extraction. Significant cost and time saving were estimated for the application of SubTSVE.
Although there was no DNAPL contaminated site suitable for a CSF application within the PURE project, additional experiments were conducted to develop a save and hydraulically controllable remediation procedure for DNAPL contaminated sites. The applicability of CSF for sites contaminated with TCE was proved by a remediation experiment carried out in a large flume which resulted in a removal rate of approx. 90 %.
Based on the experiences gained from these investigations a proceeding on the remediation of organic source zones was proposed. This decision making tool indicates the range of application for both techniques.
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- Project manager
- Research assistants
European Commission, Fifth framework programme
- Cooperation partners