In a wastewater treatment system, a clarifier has a submerged effluent launder, with a sloped, submerged plate that allows clarified liquid to exit through submerged openings. The sloped surface tends to accumulate solids, which can lead to algae growth. Typical internal scum collection system equipment prevents any efficient way to clear the accumulated sludge off the launder surface because of interferences. As disclosed here, a scum discharge area or box is placed external to the clarifier in one embodiment. Scum is wiped from a vertical surface of the launder assembly, above the sloped launder surface, and swept over a scum beach at one position in the clarifier, to drop into a lower trough and the flow out through the clarifier wall to a drop out box or scum discharge area. This allows for a rake-attached, sweeping launder wiper to be moved with the clarifier's rake to remove the accumulation of sludge from the launder's submerged surface, without elaborate moving parts. The sludge is swept back to settle in the clarifier, improving effluent quality by preventing sludge from exiting along with clarified water. In another embodiment the scum discharge box is internal, as a low-profile vertically disposed channel against the inside clarifier wall, leading to an existing scum pipe through the clarifier wall.

In a wastewater treatment system, a clarifier has a submerged effluent launder, with a sloped, submerged plate that allows clarified liquid to exit through submerged openings. The sloped surface tends to accumulate solids, which can lead to algae growth. Typical internal scum collection system equipment prevents any efficient way to clear the accumulated sludge off the launder surface because of interferences. As disclosed here, a scum discharge area or box is placed external to the clarifier in one embodiment. Scum is wiped from a vertical surface of the launder assembly, above the sloped launder surface, and swept over a scum beach at one position in the clarifier, to drop into a lower trough and the flow out through the clarifier wall to a drop out box or scum discharge area. This allows for a rake-attached, sweeping launder wiper to be moved with the clarifier's rake to remove the accumulation of sludge from the launder's submerged surface, without elaborate moving parts. The sludge is swept back to settle in the clarifier, improving effluent quality by preventing sludge from exiting along with clarified water. In another embodiment the scum discharge box is internal, as a low-profile vertically disposed channel against the inside clarifier wall, leading to an existing scum pipe through the clarifier wall.

A treatment device for treating a mixture of at least a liquid, organic solids and inorganic, mineral solids, includes a container for receiving the mixture. The container tapers in a funnel shape in a direction of a longitudinal axis of the container. An inlet tangentially supplies the mixture to the container. An outlet discharges the liquid essentially containing the organic solids from the container. A discharge apparatus serves for discharging the inorganic, mineral solids. The treatment device also includes a sleeve adapted to guide the mixture between an outer wall of the sleeve and an inner wall of the container and to guide the liquid containing the organic solids within an inner wall of the sleeve for discharge from the outlet.