Method and apparatus for mechanically and chemically treating liquids

An apparatus for mechanical or mechanical/chemical treatment of liquids containing settleable solid pollutants by flocculation, sedimentation and thickening of solid settleable pollutants contained therein, leaving separated essentially solid-free liquid, comprising:

• a treatment tank having an upper compartment and a lower compartment, the lower compartment being located beneath the upper compartment and in open communication therewith, said upper compartment being a sedimentation compartment including a plurality of downwardly inclined channels, means for introducing the liquid to be treated into said channels and flowing the liquid therethrough, means for separating out said solid pollutants from the liquid being treated as the liquid being treated flows through the channels, means for removing the said solid-free liquid from a lower portion of the channels for substantially minimizing liquid flow below the channels, and means for discharging the said solid pollutants from the lower ends of the channels such that they fall under gravity into the lower compartment under said minimized liquid flow conditions existing thereat, and the lower compartment being a thickening compartment in which thickening of the said settled solid pollutants takes place, the thickening compartment including a mechanical means for engaging the solid pollutants falling into the thickening compartment as the pollutants fall therethrough to further thicken the same, wherein the bottoms of the channels are arranged and distributed above said thickening compartment in such a manner that the lower ends of the channels run directly into said lower compartment over a major part of the area of the top of said lower compartment and a removing means separate from the thickening means and located below the thickening means.