Abstract: Disclosed herein is a wastewater treatment facility including a stacked tank clarifier having a lower tank, and an upper tank above the lower tank, the upper tank having a bottom defining a ceiling of the lower tank, and the lower tank further having a floor. The wastewater treatment facility includes a mechanism for scraping the ceiling of the lower tank. The mechanism includes a driven endless chain loop in the lower tank, and a buoyant member carried by the chain loop.

Abstract: A collector flight attachment link configured to have increased torsional load bearing ability and for supporting a collector flight on a chain including a plurality of interconnected chain links. The collector flight attachment link comprises an elongated lower link portion adapted to be interconnected with adjacent chain links in the chain. The flight attachment link also comprises a cantilevered collector flight support portion projecting upwardly from the lower link portion and including a paddle plate extending transversely to the link portion and having spaced apart first and second plate sections interconnected at their upper ends by a web section. Stress relief notches are provided between the lower edges of the paddle plate and the lower link portion.

Abstract: A hollow, polymeric sludge collector flight is provided having a sigma-shaped cross-section, including a wedge-shaped transverse indentation on its forward face, a vertically extending wear lip on its scraping edge, and a transverse gap on its rear face. The gap allows free circulation of liquid within the non-buoyant flight. The indentation structurally stiffens the mid-span section of the flight. Where additional stiffness is required, filler blocks may be placed between mounting blocks.

Abstract: A microscreen support wheel and assembly is provided comprising a polymeric support wheel having a crowned tread surface, an annular stress relief groove cut into each of its vertically flat, substantially parallel side faces and an axial bore designed to rotate around an axis included in a support wheel assembly constructed and arranged to hold a pair of microscreen support wheels in a laterally adjacent relationship on a rigid microscreen frame at an angle whereby optimum drum support is achieved.