What are the main stages of primary industrial wastewater treatment?

Primary physical-chemical wastewater treatment with reagents can be applied to a very wide range of industrial wastewater: food industry – meat, fish, dairy, vegetable washing and processing, poultry farms, culinary, confectionery; chemical industry, oil refining, paint industry, galvanics; wood – paper industry, textiles; metal processing, plastic and other waste processing industries; agriculture, livestock, poultry farming and other industries.

It is useful to discuss how primary industrial wastewater treatment is most commonly performed in companies. Physical-chemical treatment in different industries typically consists of several stages:

1. Separation of coarse pollutants by separation, filtration or gravity in settlers, screens or filters.
2. Equalization of wastewater flow and pollution in equalization tanks.
3. Primary treatment in a wastewater treatment unit – flotator, where pollutants (suspended particles) that have reacted with reagents are lifted to the wastewater surface with the help of air bubbles dissolved in water and removed from the water with scrapers.
4. Chemical reagents typically used for primary wastewater treatment:
   Reagents for wastewater pH correction;
   Coagulants – to increase the charge of fine pollutants and separate them from water;
   Flocculants (polymers) – to bind fine pollutants into larger flocs and separate them from water;
5. After primary treatment, wastewater is treated in biological treatment facilities.

The efficiency of industrial wastewater treatment depends not only on the quality of treatment equipment or the accuracy of chemical reagent doses, but also on the pollution level of the wastewater being treated, the hydraulic load (capacity) of the equipment, and the equipment’s ability to separate and remove a certain amount of pollutants from the wastewater, expressed in dry matter.

Operating principle of a wastewater treatment unit – flotator

Typically, the main stage of primary industrial wastewater treatment is the separation of suspended solids, carried out with a flotator, a wastewater treatment unit widely used throughout the world.

Wastewater treatment with a flotator is based on the flotation method, where pollutants that have reacted with reagents are lifted to the water surface by air bubbles dissolved in water and removed from the wastewater with scrapers.

Wastewater treatment with flotators is a widely applied technology in many industries for treating industrial wastewater. Flotators treat wastewater from meat and fish processing plants, dairies, secondary raw material processing, chemical, wood, paper industries, oil refining, etc. Flotators can also be used in biological wastewater treatment facilities to separate excess sludge and clarify wastewater.

A flotator is a mechanical device that can remove pollutants present in the solid (suspended solids) fraction. For this reason, the efficiency of the flotator is completely dependent on the action of chemical reagents. Chemical reagents bind fine pollutants into larger flocs and separate them from water.

UAB “Ekotakas” consults industrial companies on wastewater treatment issues, performs laboratory tests, selects and supplies equipment and reagents for wastewater treatment, and conducts audits of treatment systems. Therefore, if your company needs professional assistance with wastewater treatment issues or equipment and reagents, we invite you to contact us!