The mini mill of Slovakia Steel Mills in Strazske, which is designed to produce around 600,000 tonnes of structural steel per year, requires large quantities of treated water for direct and indirect cooling.
The central Siemens treatment plant that includes cooling towers, pumping stations, pressure sand filters, metering stations and sludge treatment facilities will supply around 7,000 cubic meters of treated water every hour for steelwork.
Siemens’ cyclone separator will remove scale from the heavily polluted water returning from the direct cooling system of the casting plant and rolling mill, following which oil will be removed by a skimmer and the remaining solids will be filtered out by downstream pressure sand filters.
After passing through bypass filtration, the backwash water from the sand filters, still contaminated with sludge, will pass through the sludge treatment plant, where polymers will be added to the sludge to separate the solids from the water in a lamella separator.
Finally, the treated water can also be fed back into the cooling system after passing through a sand filter. Siemens will automate entire water treatment plant by Simatic type S7 300 programmable logic controllers and will also supply process instrumentation equipment for monitoring water quality.
