According to the national treatment standards, the process flow of sewage treatment plants can be divided into primary, secondary and tertiary treatment. The treatment standards are as follows: the primary treatment mainly removes suspended solid pollutants from sewage, and most physical treatment methods can only meet the requirements of primary treatment.

Primary treatment: the primary treatment mainly includes coarse grids, fine grids, primary sedimentation tanks and other structures, which are mainly used to remove coarse particles and suspended solids.

Secondary treatment: the secondary treatment mainly includes biological pond, secondary sedimentation pond and other structures, which are mainly used to remove non-precipitated suspended matter and degradable organic matter.

Tertiary treatment: Tertiary treatment mainly includes ceramsite filter material, rapid filter, disinfection tank and other structures, which are mainly used to remove pollutants from water and make the water reach the reuse standard.