The plant is designed to treat up to 55 m3/hr of water effluent from various sources in the ArcelorMittal Vanderbijlpark Works. The feed effluent is stored in a buffer facility before pre-treatment, comprising course filtration and pH adjustment. The feed liquor is then fed to a packed bed stripping column to preheat the feed further and strip off any volatile components such as CO2 or other, which may affect plant capacity.
The preheated feed liquor is piped into the Evaporation circuit which comprises a Single Effect Mechanical Vapour Recompression (MVR) Evaporator, circulation pump, heater with titanium wetted parts and a high pressure turbo fan train. Vapour leaving the Evaporator vessel is drawn through a mesh water separator and compressed in a two stage 1100 kVA fan train. It is recycled to the evaporator heat exchanger as the energy source for the evaporation process.
The concentrated evaporator liquor is fed to a Single Effect Mixed Bed Crystalliser where steam is used for the crystallisation process. To maintain the crystal concentration in the crystalliser, a portion of the crystal slurry is pumped to a centrifuge which produces a moist crystal product for disposal. Process and steam condensate is returned to the clients’ water tank.