What are the domestic sewage treatment methods?

1. Physical treatment: the pollutants in wastewater are treated, separated and recovered by physical action. For example, precipitation method can remove suspended solids with relative density greater than 1, filtration method can remove suspended solids in water, and evaporation method can concentrate non-volatile substances and soluble substances in wastewater.

2. Chemical treatment: treatment and recovery of soluble wastes or colloidal substances by chemical reaction or physical and chemical action. For example, oxidation-reduction method is used to remove reducing or oxidizing pollutants in wastewater and kill pathogenic bacteria in natural water.

3. Biological treatment method: organic pollutants in wastewater are treated by biochemical action of microorganisms. For example, biological filtration and activated sludge process are used to treat domestic sewage or organic production wastewater, so that organic matter can be transformed and degraded into inorganic salts and purified.

4. Biological contact oxidation method: biological contact oxidation method is used to treat wastewater, that is, biological contact oxidation process is used to fill fillers in the biological reaction tank, and oxygenated sewage submerges all fillers and flows through the fillers at a certain flow rate.