In the steel industry water is of high importance. It is used for
- Cooling
- Steam generation
- Waste transfer
- Dust control
As heat is used in any manufacturing process of the steel industry, the major need of water is for cooling purposes of the various facilities such as the furnace body and the actual products.
Less than 10% of this water is actually consumed. The majority is reused in recirculating systems, for example, when waste water from direct cooling is recycled back after adding make-up water. Another way to improve water efficiency is to recycle waste water and cascading water use from higher to lower quality.
Water effluents are those waters that cannot be recycled back even after treatment. Steel plants that aim for zero discharge of water effluents will treat the water to enhance its quality and use it for example in raw material dust suppression. Other plants will treat the effluents to comply emission limits in order to discharge it back to natural sources such as rivers and lakes.
Nevertheless, the monitoring of the water quality is crucial for efficient water circulation and safe plant operation.