Various sorts of process water, foaming agents and a new chelating surfactant have' been investigated in the chemical optimization of flotation of waters generated at laboratory and white water from mechanical pulping. Turbidity measurements, the Orcinol method for quantitative carbohydrate analysis and total organic carbon (TOC) as well as gas chromatography (GC) of extractives, have been carried out to determine the removal and characteristics of Dissolved and Colloidal substances (DisCo). The tests have been realized under different conditions, such as using different flotation cells, foaming agents and complexing agents at different temperatures and pH values. It was found that a reduction of the white water turbidity of 70% and a 50% removal of the lipophilic substances from the white water can be obtained in a 'single-stage flotation unit, and that the selection of suitable flotation equipment, foaming agents and solution conditions plays a very important role in the removal capacity of the unwished substances.