Power plants often produce wastewaters that contain salts, such as those from wet gas scrubbing, coal pile run-off, and leachate from gypsum stacks. Evaporation of those liquid wastes in a modern zero liquid discharge system produces clean water that is recycled into the plant plus a solid product suitable for landfill disposal.
The chemical reaction that takes place in caustic soda production: Na2CO3 + Ca(OH2) ↔ 2NaOH + CaCO3. The heat of reaction of the above reaction is 2100 calories, soda ash with concentration 20% is added to the dissolving tank which is mixed with recycle stream of weak liquor obtained from the rotary filter.
Waste water and waste water treatment in the Steel Plant. Steel plants use a large amount of water for a variety of usage which includes cooling, dust suppression, cleaning, temperature control (heat treatment), transport of waste materials (ash, sludge, and scale etc.), and other usages.