Intensifying the Cleaning of Emulsion- and Oil-Bearing Waste Water from Rolled-Product Manufacturing by Electroflotation

It is shown that it is possible to intensify the cleaning of emulsion- and oil-bearing waste water from rolling-mill operation. The water is given a secondary treatment in an electrical flotation unit that automatically controls current density and electrode spacing. Operating regimes for the unit are developed for the secondary cleaning of emulsion-bearing waste water from cold-rolling mills after primary cleaning in horizontal settling tanks with reagent FeCl₂, a small amount of H₂SO₄, and spent pickling solution. The optimum regime for use of the flotation unit for the secondary cleaning of oil-bearing waste water from hot-rolling mills is determined. A cleaning level of 94–95% is achieved for waste water in which the initial content of petroleum products is 100 mg/liter.