Das Projekt "SAFIRA - Abstracts of the Workshop of November 17-18, 1999 at Bitterfeld / Germany" wird vom Umweltbundesamt gefördert und von Umweltforschungszentrum Leipzig-Halle, Projektbereich Industrie- und Bergbaufolgelandschaften durchgeführt. The SAFIRA project (Sanierungsforschung in regional kontaminierten Aquiferen) focuses an the development of reactive walls for the treatment of regional contaminated aquifers. The project is managed by UFZ (Umweltforschungszentrum Leipzig-Halle) and the University of Tübingen. Within the SAFIRA project, different research groups are investigating a number of different technologies at an underground test site in Bitterfeld. Among them is a consortium from the Netherlands, lead by TNO (Netherlands Organisation for Applied Scientific Research), with Tebodin, HBG/HWZ and Shell as partners. The Dutch research project is supported by NOBIS (Netherlands Research Programme for Biological in situ Remediation). Fall 1999, the SAFIRA programme at Bitterfeld had come at an interesting point. The test site had been officially opened, most results of the on-site mobile test unit had been obtained and the in-situ reactors had been started up. On November 17-18, 1999, UFZ and TNO jointly organised a workshop at the test site in Bitterfeld. The Workshop was attended by about 50 representatives from the different research groups involved in SAFIRA, NOBIS representatives and members of the Knowledge Exchange Group related to the Dutch research project. The workshop focused on: - the methods applied; - the results obtained so far; - practical, large scale solutions for the regional groundwater problem. This report presents the workshop programme, the abstracts of the presentations and a selection of the slides that were used within the brainstorm session. We do hope that the workshop and this report will be followed-up by a further and fruitful knowledge exchange between all parties involved and that this may contribute to finding innovative, optimal solutions for the regional groundwater problems in Bitterfeld and other areas.