Circular radial flow sedimentation tanks are more
usually associated with waste water treatment or
industrial processes in this country than with
drinking water clarification. They are used,
particularly in tropical countries, for the treatment
of heavily silted waters and are usually fitted with
rotating sludge scrapers, which direct the sludge
to a central hopper for removal. A variant on this
tank, where space constraints so dictate, is the
square radial flow sedimentation tank, with
curved corners at bottom negotiated by a specially
designed telescoping rotating sludge scraper.