Das Projekt "Langzeitleistung durchlaessiger reaktiver Trennschichten, die bei der Sanierung von kontaminiertem Grundwasser eingesetzt werden" wird vom Umweltbundesamt gefördert und von Universität Karlsruhe, Geologisches Institut, Lehrstuhl für Angewandte Geologie durchgeführt. Objective: Problems to be solved: Contaminated land, landfills and sediments pose a serious environmental threat by polluting groundwater in the surrounding area. In 14 European countries contamination caused by uranium represents a particularly serious danger where drinking water resources might be affected. Other heavy metals and organic pollutants can also have a strongly deleterious effect on groundwater. Available technologies (e.g. pump-and-treat) fall short of solving the problem because their performance is not yet adequate for effective remediation. Permeable reactive barriers (PRB) represent a promising innovative technology for passive in-situ groundwater remediation. Little is known, however, about the long-term behaviour (formation of coatings and precipitates, reduction of permeability) of PRB systems. Scientific objectives and approach: The aim of the project is to elaborate the scientific basis for, laboratory and pilot-scale testing of and the practical application of a considerably more efficient and cost-effective in-situ reactive barrier technology targeting groundwater contaminants. General objective is to evaluate and enhance the long-term performance of PRB systems, especially of those targeting heavy metals and organic contaminants using sorption and/or precipitation mechanisms. The approaches taken to meet the project objectives will be the characterisation of different reactive materials and relevant attenuation processes in the reactive matrix of the PRB and their long-term behaviour. Technological methods to enhance the long-term efficacy and cost-effectiveness of the PRB system will be developed and tested under realistic conditions. The primary model test site will be an area in southern Hungary contaminated by uranium mining - thus including a region which is due to become part of the European Union. Expected impacts: The results of this project are expected to play a major role in establishing the permeable reactive barrier technology as an accepted, reliable and cost-effective method for the remediation of contaminated groundwater. The broad spectrum of activities within the proposal offers considerable utilisation opportunities. The investigation of potentially suitable reactive materials for specific target contaminants and the clarification of attenuation processes and ageing mechanisms will enable the optimisation of reaction conditions and barrier design. New technological developments like specially taylored contaminant-targeting ligands and electrokinetic enhancement are aimed at improving the effectiveness of the groundwater-cleaning task of PRB systems. The anticipated spread in the application of PRB systems will also necessitate regulation. As far as we are aware, the Federal Institute for Materials Research and Testing (BAM) in Berlin is currently the only regulatory body in Europe in a position to develop guidelines and regulations on reactive barriers...