SMS group has built a new continuous galvanizing line (CGL) for Magnitogorsk Iron and Steel Works MMK in Magnitogorsk (Russia). The requirement was to supply the system with sufficient quantity of cooling water in the requisite quality and at the necessary temperature.
In addition, the wastewater of the CGL had to be conditioned prior to its discharge to the public sewage water system. In order to fulfill these tasks, SMS group installed a water supply and treatment system and a wastewater treatment system in 2017.
Furnace cooling of the galvanizing line is effected by the primary, indirect cooling circuit which itself is recooled by the secondary cooling circuit through heat exchanger. Recooling of the secondary circuit is through cooling towers. The secondary circuit is cleaned by means of strainer filters. The cooling water is stabilized by the addition of chemicals. In order to compensate the evaporation losses through the cooling towers and the leakage losses in the primary circuit, a reverse osmosis system has been installed to produce demineralized water.
|Cooling capacity||8,800 kw|
|Cooling water circulation flowrate||583 m³/h|
|Cooling water temperature||35°C|
|Pressure difference||0.6 MPa|
After pretreatment by emulsion cracking, neutralization, flocculation and sedimentation, the waste water is passed to the heart of the system, the membrane bioreactor. Here oxygen and nutrients are added to the medium to induce bacteria in the reactor to decompose harmful substances. The bacterial mass, the so-called activated sludge, is separated from the cleaned waste water through a membrane so that waste water with only minor pollution load is discharged to the public sewerage system.