Clarifier with submerged effluent launder and launder sweeper system

A wastewater treatment clarifier having an effluent launder for withdrawal of effluent from the clarifier, comprising:

• the clarifier being essentially circular and having a peripheral clarifier wall, and the launder being connected to the inside of the clarifier wall,
• the launder being at least partly submerged below the liquid level in the clarifier,
• the clarifier including a rake arm rotating about a center of the clarifier in a sweeping motion around the clarifier,
• a scum surface at the clarifier wall at a liquid surface level in the clarifier, above the launder, and scum removal equipment for removing scum from the scum surface and out of the clarifier without interfering with the movement of the sweeping launder wiper,
• the scum removal equipment including a discharge pipe or conduit extending out through the clarifier wall at a position below the effluent launder, and an internal scum drop out box positioned adjacent to the scum surface and extending down the inside of the clarifier wall to a connection with the scum discharge conduit, and including a scum wiper engaged against the scum surface and movable around the clarifier to sweep scum and connected to the rake arm for movement with the rake arm, a generally flat, gently sloped scum ramp at one position in the circumference of the clarifier, adjacent to the inside of the clarifier wall and to the internal scum drop out box and sloped upwardly in the direction of movement of the scum wiper, a generally horizontal scum sweeper connected to the scum wiper to sweep scum up the scum ramp, and a scum drop channel connected to the internal scum drop out box and adjacent to an upper end of the scum ramp for receiving scum swept from the scum surface and from the scum ramp, so that wiped scum drops into the drop channel, drops down through the internal scum drop out box and is discharged by the scum discharge pipe.

A wastewater treatment clarifier having an effluent launder for withdrawal of effluent from the clarifier, comprising:

• the clarifier being essentially circular and having a peripheral clarifier wall, and the launder being connected to the inside of the clarifier wall,
• the launder being at least partly submerged below the liquid level in the clarifier,
• the launder having inlet orifices submerged below the liquid level of the clarifier,
• the submerged launder comprising an inwardly/downwardly obliquely angled plate connected to the inside of the clarifier wall as an upper side of the launder, a shelf connected to the clarifier wall at a level below the connection of the obliquely angled plate to the wall to form a bottom of the launder, the obliquely angled plate being connected to an inward side of the shelf, and the obliquely angled plate having said inlet orifices to admit effluent water from the clarifier,
• the clarifier including a rake arm rotating about a center of the clarifier in a sweeping motion around the clarifier,
• a sweeping launder wiper having a wiper blade positioned against the obliquely angled plate and connected to the rake arm near an outer end of the rake arm so as to sweep the wiper blade along the obliquely angled plate through full circles of movement around the clarifier so as to sweep settled sludge off the obliquely angled plate so that the sludge drops to the bottom of the clarifier,
• a scum surface at the clarifier wall at a liquid surface level in the clarifier, above the obliquely angled plate of the launder and above the sweeping launder wiper, and scum removal equipment for removing scum from the scum surface and out of the clarifier without interfering with the movement of the sweeping launder wiper,
• the sweeping launder wiper blade including a flexible outer section at an outer end of the wiper blade which has a bendable, flexible, rubbery wiper element retained by spring steel bands at an upper end of the wiper element, the spring steel bands tending to return the flexible outer section toward a straight configuration while allowing bending to accommodate any interfering structures as well as imperfections in the shape of the clarifier wall to allow for differences in the distance of the clarifier wall from the sweeping launder wiper as the wiper travels around the clarifier.

A wastewater treatment clarifier having an effluent launder for withdrawal of effluent from the clarifier, comprising:

• the clarifier having a peripheral clarifier wall, and the launder being connected to the inside of the clarifier wall,
• the launder being at least partly submerged below the liquid level in the clarifier,
• the clarifier including a rake arm rotating about a center of the clarifier in a sweeping motion around the clarifier,
• a scum surface at the clarifier wall at a liquid surface level in the clarifier, above the launder, and scum removal equipment for removing scum from the scum surface and out of the clarifier, the scum removal equipment including a scum drop out box secured at the clarifier wall, a scum wiper engaged against the scum surface and movable around the clarifier to sweep scum and connected to the rake arm for movement with the rake arm, a generally flat, gently sloped scum ramp at one position in the circumference of the clarifier, adjacent to the inside of the clarifier wall and to the scum drop out box, a generally horizontal scum sweeper connected to the scum wiper to sweep scum up the scum ramp, and including a scum drop channel connected to the scum drop out box and adjacent to an upper end of the scum ramp, for receiving scum swept from the scum surface, so that wiped, swept scum drops into the scum drop channel and exits to the scum drop out box.