Background The BREF (BAT reference document) which concerns the Chlor-Alkali manufacturing industry, and was adopted by the EC in December 2001, states that membrane technology is the best available technique in chlorine plants. The other technologies used, mercury cells and asbestos diaphragm cells, have a significant negative environmental impact and are considered outdated. A way has to be found to convert plants using these technologies to membrane cell technology. The change to membrane cells has been slow in Western Europe because most of the existing chlorine plants were installed in the 1970s with a plant life of 40-60 years and there has been no drive to change technology. GE Plastics at Bergen op Zoom in the Netherlands, uses membrane cells in the production of polycarbonate. In the production process, sodium chloride solution (brine) is used in the electrolysis in order to make chlorine. All chloride is recovered in the next step of the process, polymerisation and the brine is then produced as a waste stream. Theoretically a closed loop of brine could be created but the re-use of brine is currently impossible because the brine from the polymerisation process contains a number of impurities that could seriously damage the membranes in the chlorine production process. Recently, GE Plastics developed a technology that is capable of removing all the relevant impurities from the brine and concentrating it. Thus, the brine could be re-used in the chlorine cells and a closed cycle could be created, leading to important savings in raw materials, energy and waste treatment. This technology produced very good results at pilot scale. Objectives The project will demonstrate for the first time at full scale that the brine recovery process is technically and financially viable and that it leads to significant savings of raw materials and energy compared to the current situation. If the project is successful, it could have a positive effect on phasing out mercury and diaphragm cells in chlorine plants. Since the feedstock savings are substantial, a change to membrane cells would be economically more feasible. Results This project did not star