A widespread problem with contact cooling water in continuous casting and rolling mills is the presence of oil and grease.
Flotation is used to remove oil, whereby the oil floats on the surface and can be separated and channelled to suitable disposal systems by means of scraper blades or dedicated equipment such as oil skimmers.
The oil removed can be further concentrated using a hot system that enables it to be collected.
Flotation can be used for separation of specific pollutants from water. Flotation is enhanced by air insufflation from the bottom of the tank and the addition of chemical reagents; the sludge floating on the water surface can be removed using screw conveyors or skimming blades.