Waste treatment system having integral intrachannel clarifier

In an aerobic system for treating wastewater containing settlable solids of the type having an oxidation ditch defining a trough-like channel having a bottom and spaced upstanding side walls for retaining the waste liquid in a continuous substantially closed flow path, means for introducing wastewater influent into the flow path, means for removing waste sludge as mixed liquor from the flow path, and means for moving the mixed liquor in a single substantially horizontal direction in the flow path at sufficient velocity to prevent settling of the suspended solids, the improvement in combination therewith comprising means positioned within said flow path for clarifying said mixed liquor, said clarifying means comprising tank means for creating a zone of relatively quiescent waste liquid in the upper portion of said channel to permit suspended solids to settle by gravity within said quiescent zone to produce clarified waste liquid, clarifier inlet means for permitting entry of unclarified mixed liquor from the flow path into the quiescent zone at a relatively slow rate, clarifier outlet means for removing a portion of the clarified waste liquid from the tank means, and baffle means associated with said tank means for permitting the settled solids to return from said quiescent zone to the flowing mixed liquor within said channel, but preventing movement of excessive quantities of flowing waste liquid into said quiescent zone, said baffle means comprising a plurality of spaced parallel slightly overlapping inverted V-shaped angle members each having a pair of angularly disposed legs extending across the flow path in spaced relationship with said channel bottom, adjoining legs of adjacent angle member being spaced to permit the passage of settled solids therebetween, said angle members being configured such that settling of suspended solids occurs in the quiescent zone above said baffle means.

In intrachannel clarifier for clarifying waste liquid containing settlable solids for use in an aerobic waste water treatment system of the type having means for retaining the waste liquid in a continuous substantially closed flow path, means for introducing waste water influent into the flow path, means for removing waste sludge as mixed liquor from the flow path, and means for moving the waste liquor in a single direction in the flow path at sufficient velocity to prevent settling of the suspended solids, said clarifier comprising:

• tank means positionable within said retaining means for creating a zone of relatively quiescent waste liquid in the upper portion of the tank means to permit suspended solids to settle downwardly by gravity within the quiescent zone to produce clarifier waste liquid;
• clarifier inlet means included in said tank means to permit entry of unclarified mixed liquor from the flow path into the quiescent zone at a relatively slow rate;
• and
• baffle means associated with said tank means for permitting the settled solids to return from the quiescent zone to the flowing mixed liquor within the retaining means but preventing movement of excessive quantities of flowing mixed liquor into the quiescent zone, said baffle means comprising a plurality of spaced sloping non-vertical surfaces configured to extend across the flow path substantially transversely of the waste liquid flow direction, such that settling of the suspended solids occurs in the quiescent zone above the baffle means.