Abstract: The river water in Poland has, to a great extent, such a high salinity that it cannot be used as drinking water, agricultural or industrial water. A large environmental project is now under progress in Katowice, Poland, in order to eliminate the wastewater discharge from two coal mines — Debiensko and Budryk. The highly brackish water will be desalinated in a reverse osmosis plant, followed by vapor compression distillation with seed crystals (RCC), crystallization and sodium chloride drying. This zero discharge process will produce about 8,000 m3/d drinking water an 370 tonnes/d NaCl. The paper describes the design of the plant. Trial operation of pre-treatment and reverse osmosis in a pilot plant for design of the full-scale plant at Debiensko is described in a separate paper.