1、 The modern sewage treatment technology can be divided into first level, second level, and third level treatment according to the degree of treatment.
First level processing,
The main purpose is to remove suspended solid pollutants from sewage, and most physical treatment methods can only meet the requirements of primary treatment. After primary treatment, sewage can generally remove about 30% of BOD, which does not meet the discharge standards. The first level processing belongs to the preprocessing of the second level processing.
Secondary processing,
Mainly removes colloidal and dissolved organic pollutants (BOD, COD substances) in sewage, with a removal rate of over 90%, to meet the discharge standards for organic pollutants.

Third level processing,
Further processing of recalcitrant organic matter, nitrogen, phosphorus, and other soluble inorganic substances that can lead to eutrophication of water bodies. The main methods include biological nitrogen and phosphorus removal, coagulation precipitation, sand ratio, activated carbon adsorption, ion exchange, and electroosmotic analysis.
Introduction to Industrial Wastewater Treatment Equipment
According to the classification of sewage sources, sewage treatment is generally divided into production sewage treatment and domestic sewage treatment. Production wastewater includes industrial wastewater, agricultural wastewater, and medical wastewater, while domestic wastewater refers to the wastewater generated in daily life. Wastewater treatment is widely used in various fields such as construction, transportation, energy, petrochemicals, environmental protection, urban landscape, healthcare, and catering, and is increasingly entering the daily lives of ordinary people.