Improvement of the solid-liquid separation efficiency in the secondary sedimentation tank of the biological treatment
process, is known to be increasing effectiveness of the overall system operation. Sewage treatment plant effluent SS is
composed of most organic substances. In order to reduce the SS component in the secondary sedimentation tank discharge,
fine SS components constituting the heterogeneous should be increased by its own aggregation (self flocculation), so that
can be deleted through their precipitation. So, it is improved through using the installation of double rectification wall
in this secondary tank. In case, sewage is rapidly increased due to the daily change of the influent water, it was confirmed
that suspended solids caused by the impact load are processed stably. Therefore, there is a need for a facility installation
which can be its own aggregation for reduction suspended solids in secondary sedimentation tank.