Peripheral drive sludge scraper is a machine which scrape and discharge sludge in round primary sedimentation tank, secondary sedimentation tank and sludge thickening tank. Sometimes it is also called water clarifier for sedimentation tank, standard products working diameter ranges from 12m to 50m. According to the different bridge type, it can be divided into: Half bridge sludge scraper and Full bridge sludge scraper.

Peripheral drive sludge scraper is composed of service bridge, scraper blades, steady flow tube, sludge scraping truss, overflow weirs, center supporting frame, driving unit, etc. The driving unit is installed at the end of bridge, walks on border of circle tank and scrape sludge while travelling. The bridge fitted with scraper arm and scraper blades that rotate in clockwise direction and thus convey the debris (sludge, etc.) towards the middle of the reinforced concrete tank, from where sludge is discharged. The clean water flows through the V-notched weirs and flows into a discharge channel.