Multi-stage gravity classification treatment system and method for over-wet solid waste and bad soil

The invention discloses a multi-stage gravity classification treatment system and method for over-wet solid waste and bad soil. The system comprises two treatment areas. A channel is arranged betweenthe two treatment areas. Multiple primary sedimentation tanks and a secondary sedimentation tank are arranged in each treatment area. The primary sedimentation tanks are distributed around the outsideof the secondary sedimentation tank. Each of the primary sedimentation tank and the secondary sedimentation tank is provided with a floating stirring device. Coarse-particle piling pits are arrangedbetween adjacent primary sedimentation tanks in the same treatment area. The surface of each primary sedimentation tank is provided with a screen. The upper part of each primary sedimentation tank communicates with the secondary sedimentation tank through a first overflow channel. The treatment areas are provided with first opening and closing mechanisms for opening and closing the first overflowchannel. A three-stage sedim