Precipitation mechanism for sewage pretreatment and sewage treatment system

The invention relates to the technical field of sewage treatment, and discloses a precipitation mechanism for sewage pretreatment and a sewage treatment system.The precipitation mechanism comprises a precipitation mechanism body arranged in a treatment box and a treatment cavity in the treatment box, the precipitation mechanism body comprises a mounting part arranged in the treatment cavity, and the mounting part comprises a mounting plate; the mounting plate is provided with partition plates for dividing the treatment cavity below the mounting plate into a plurality of precipitation cavities, the mounting plate is provided with water inlet holes corresponding to the precipitation cavities, and the water inlet holes are provided with sealing assemblies for sealing the water inlet holes; a feeding groove is formed in the side wall of the precipitation cavity and is positioned at the upper end part; and a sewage outlet and a clear water outlet pipe are arranged below the precipitation cavity. By means of the st