Sedimentation is the process by which the solid substances suspended in water settle on the tank bottom, thanks to the force of gravity
only. The sedimented material is scraped, collected and conveyed out of the sedimentation tank. The sedimentation of waste water,
before the biological treatment, is defined as Primary Sedimentation (Primary Clarifiers), while the sedimentation of water after
the biological treatment is called Final or Secondary Sedimentation (Final/Secondary Clarifiers).
The Scrapers used for primary sedimentation
are equipped with bottom scrapers and a system to remove the floating material.
The Scrapers used for secondary sedimentation are
equipped with a scraping or suction system, in the second system the sludge is continuously sucked from the tank bottom.