Treatment of water

Water treatment apparatus to treat a saline water feed, the apparatus comprising

• a crystallisation stage with an elongate conduit located within a cold environment, the elongate conduit being configured to receive said saline waterfeed and to allow said saline water feed to pass through the conduit;
• cooling means to keep the cold environment at a temperature below 0° C. to ensure formation of a slurry of ice and brine inside the elongate conduit as a result of heat exchange between the saline water feed inside the conduit and the cold environment;
• and
• a separation stage in flow communication with the crystallisation stage to receive said slurry of ice and brine from the elongate conduit and to separate ice crystals from brine,
• the elongate conduit being of a material, or having an inner material layer, with a thermal conductivity of less than 5 W/m·K and having a length of at least 50 m.