Concept of wastewater treatment

Physically speaking:

Wastewater treatment is a wastewater treatment method that separates and recovers insoluble suspended pollutants (including oil film and oil bead) in wastewater through physical action. It can be divided into gravity separation method, centrifugal separation method and screen filtration interception method. The treatment method based on the principle of heat exchange also belongs to the physical treatment method.

From a chemical point of view:

Waste water treatment is a waste water treatment method that separates and removes dissolved and colloidal pollutants in waste water or converts them into harmless substances through chemical reaction and mass transfer. In the chemical treatment method, the treatment units based on the chemical reaction produced by adding chemicals are: coagulation, neutralization, oxidation-reduction, etc; The treatment units based on mass transfer include extraction, stripping, stripping, adsorption, ion exchange, electrodialysis and reverse osmosis. The latter two treatment units are also called membrane separation technology. Among them, the treatment unit using mass transfer has both chemical and related physical effects, so it can also be separated from the chemical treatment method and become another kind of treatment method, which is called physical chemical method.

From a biological point of view:

Wastewater treatment is a wastewater treatment method that converts organic pollutants in solution, colloid and micro suspension state into stable and harmless substances through microbial metabolism. According to different microorganisms, biological treatment can be divided into aerobic biological treatment and anaerobic biological treatment. Aerobic biological treatment method is widely used in wastewater biological treatment. According to tradition, aerobic biological treatment method can be divided into activated sludge method and biofilm method. Activated sludge process itself is a kind of treatment unit, which has a variety of operation modes. The treatment equipment belonging to biofilm process includes biofilter, biological rotating disc, biological contact oxidation tank and biological fluidized bed. Biological oxidation pond method is also called natural biological treatment method. Anaerobic biological treatment, also known as biological reduction treatment, is mainly used to treat high concentration organic wastewater and sludge. The treatment equipment used is mainly digestion tank.

The biological contact oxidation process is used to treat wastewater, that is, the biological contact oxidation process is used to fill the filler in the biological reaction tank. The oxygenated sewage immerses all the filler and flows through the filler at a certain flow rate. The filler is covered with biofilm, and the sewage is in wide contact with the biofilm. Under the metabolism of microorganisms on the biofilm, the organic pollutants in the sewage are removed and the sewage is purified. Finally, the treated wastewater is discharged into the biological contact oxidation treatment system and mixed with domestic sewage for treatment. It is discharged after chlorine disinfection. Biological contact oxidation is a biofilm process between activated sludge process and biofilter process. It is characterized by setting fillers in the tank, aerating the sewage at the bottom of the tank, and making the sewage in the tank in a flowing state, so as to ensure that the sewage is in full contact with the fillers immersed in the sewage, and avoid the defect of uneven contact between sewage and fillers in the biological contact oxidation tank. This aeration device is called blast aeration.