Abstract: Scum skimmer apparatus having a skimmer blade slideably disposed on support rods extending downwardly from an oscillating bridge which is moveable over the clarifying tank in a biological waste treatment plant. An air tight ballast chamber is secured to the skimmer blade having a source of air communicating with the ballast chamber, the source having a valve for controlling the air flow. As the bridge moves toward the scum trough at one end of the clarifying tank the air is evacuated from the ballast chamber, allowing the blade to engage the surface of the liquid. Upon moving away from the scum trough air is pumped into the ballast chamber providing a buoyancy force which raises the skimmer blade away from the surface. When the opposite end of the clarifying tank is reached the skimmer blade is lowered back to the water by venting the air out of the ballast chamber.

Abstract: The disclosure relates to clarifiers for use in the gravity separation of suspended particles from liquids. A clarifier according to the invention includes a tank having a sludge outlet through which settled sludge can be removed and means for conveying settled sludge towards said outlet. A gantry is supported for movement above the surface of liquid in the tank. Gantry drive means are provided and are adapted to cause the gantry to perform repeated passes over said surface. A sludge conveyor device is submerged in liquid in the tank in use and is positioned at a clearance above the bottom of the tank. Conveyor drive means are coupled to the sludge conveyor device. The device is coupled to the gantry by support means arranged so that the device moves with the gantry and sweeps over the bottom of the tank as the gantry performs said repeated passes above the surface of liquid.

Abstract: A sludge settling basin in which a platform is movable over the basin and supports a siphon tube having a first portion extending to adjacent the floor of the basin, a second portion extending over the basin and a third portion extending downwardly into the channel of the side wall of the basin, the material in the channel being removed by a pump with a sufficient rate for the level of liquid in the channel always to be below the level of liquid in the settling basin, so that the sludge is siphoned from the basin into the channel and is removed by the pump.

Abstract: A solids remover for high rate algae ponds has a longitudinally extending pond within which there is a transversely extending settling basin, the settling basin having separate zones for the settlement of different solids. A carriage is supported for movement across the settling basin and carries pumping means. A nozzle arrangement on the inlet to the pumping means is effective to retrieve solids from any one or more of the separate zones and discharges the retrieved solids to a stationary solids receiver in any position of the carriage.

Abstract: Dewatering apparatus is provided, for use in the treatment of particulate material in water, particularly suspensions of sand in water. The apparatus is also provided with means for classifying sand or like particulate material by size. The apparatus employs a sloped trough extending upwardy from a well having sand and water therein, and with a longitudinally moveable rake being provided, with a particularly novel mechanized raking motion, preferably hydraulically operated. The classifying is done by varying the inflow and consequently the overflow of water through the apparatus, varying the water flow from spray pipes extending along side of the discharge trough, or by speeding up the operation of the apparatus.

Abstract: A sludge removal system for use in the removal of settled sludge collected on the bottom surface of a circular clarifier. The system includes a plurality of self-supporting sludge receiving conduits of various lengths extending radially outward from the center of the tank in a common horizontal plane. Each conduit has a sludge pick-up port associated with the outer end thereof. Vertical riser tubes extend upward from the inner ends of the conduits into a sightwell assembly. At the upper end of each riser tube is a flow control valve arrangement to regulate the amount of sludge flow through each conduit. The valve indicates a pipe within a pipe, both pipes having slotted openings cut therefrom, to provide a variable flow orifice the size of which may be controlled by rotating the inner pipe about the stationary outer pipe. The upper edges of the slotted openings extend above the static liquid level in the clarifier.

Abstract: An automatic foam remover for a substantially rectangular flotation tank in which during operation thereof a layer of foam accumulates on the top surface of a liquid body therein, said foam remover comprising a hollow beam extending horizontally across the top of the tank and being movable back and forth between two parallel side walls of the tank by means of motor-driven endless chains mounted on the tank and operably connected with said beam, the hollow interior of which is in communication with a source of vacuum. Said hollow beam is provided with a longitudinal bottom slot through which a vane which is pivotally mounted within the hollow beam, extends downwardly through said layer of foam, whereby said vane during the movement of the beam is alternately forced into engagement with the two edges of said slot and thereby causes the layer of foam to be subjected to the action of the source of vacuum alternately at one side of the vane and at the other side thereof.