Flotation is a technological technique that, in relation to water and wastewater treatment, is used to remove fats, oil products, and reduce the content of organic and suspended solids. The flotation process is based on the difference in the wettability of media (hydrophobicity and hydrophilicity). Hydrophobic particles “stick” to the air bubbles that are supplied to the treated water, and together with them rise to the surface. The foam formed on the surface of the flotator (flotation apparatus), the so-called flotation sludge, is collected using scrapers in trays and sent for dehydration.
Purified water from the thickness of the flotator is sent to further stages of processing. According to the method of saturation of the treated medium with air bubbles, pressure flotation, impeller flotation, flotation using porous materials to obtain bubbles, and flotation with the production of gas bubbles by electrolysis are distinguished. Pressure flotation is the most effective and, as a result, widespread.

The pressure flotation process usually consists of the following steps:
– input of reagents (coagulant, flocculant) into the treated water;
– slow mixing and feeding the mixture into the flotation chamber;
– saturation of the water mixture with air in the saturator and supply of air-saturated water to the flotation chamber;
– the formation of many small air bubbles in the flotation chamber;
– convergence of hydrophobic particles with air bubbles and the formation of their conglomerates;
– conglomerates of hydrophobic contaminants with air float to the surface of the flotation chamber from where they are removed;
– purified water is removed from the deep layers of the flotation chamber and fed for further processing.
The efficiency of the flotation process depends on the hydrophobic properties of the removed particles, on the size and number of air bubbles formed, as well as on the resistance of these bubbles to destruction.

Flotation cannot be an independent cleaning, but is one of the stages of complex installations. Usually flotators are installed after settling tanks, because The flotator allows you to remove those substances that cannot be removed by settling.