Abstract: Apparatus and method is described for dewatering sludge obtained from a flotation tank, which efficiently handles the sludge and avoids the need for adding polymers to reflock the sludge. The sludge dewatering portion includes a conveyor (40, FIG. 1) which has an uppath portion (42) that receives sludge that is dropped over a cliff (32), the conveyor having a downpath portion (44) which firmly compresses the sludge as it continues to move along the conveyor. The conveyor preferably extends at an incline to the horizontal with the downpath portion lying higher than the uppath portion, and with a fluid conduit lying under the conveyor and carrying liquid downwardly along the incline to a pump (74) that pumps the liquid along a return conduit (80) back to the flotation tank. One conveyor includes an elongated shaft (50, FIG.

Abstract: A floatation separation method is described for separating pieces of fruit or vegetable of the same type, but wherein desirable pieces have a slightly different specific gravity from the undesirable ones, and all have a specific gravity about the same as that of water. The pieces (12, FIG. 3 ) are placed near the surface of a body of water, and a cloud (40) of tiny air bubbles is maintained in the water. As the bubbles float to the surface they encounter the articles and slightly increase their buoyancy. The increase in buoyancy is slight and uniform, so those articles having a density slightly greater than that of the water will remain at the water surface, while those of a slightly greater density cannot be floated by the air bubbles and will sink to the bottom. The cloud of air bubbles is created by allowing air at about atmospheric pressure, to emerge from apertures in a rapidly spinning rotor that open in a direction primarily opposite to the spin direction.

Abstract: A wastewater flotation separation system is provided, which operates effectively with a minimum of maintenance. The apparatus includes a container (12) for holding wastewater, an inlet (14) located at a lower portion of the container, and an aerator (24) adjacent to the inlet for generating air bubbles that cling to waste particles to bring them to the water surface. A skimming apparatus (30) which skims particles off the surface of the wastewater into a sludge receiver (44) includes a beach device (42) with an inclined upper surface (40), and a belt device (34) that moves a series of scrapers (32) along the surface of the water and along the beach device into the sludge discharge. Each scraper includes a flap of resilient material which is bent as it scrapes along the inclined beach surface.

Abstract: A wastewater flotation separation system is provided, which operates effectively with a minimum of maintenance. The apparatus includes a container (12) for holding wastewater, an inlet (14) located at a lower portion of the container, and an aerator (24) adjacent to the inlet for generating air bubbles that cling to waste particles to bring them to the water surface. A skimming apparatus (30) which skims particles off the surface of the wastewater into a sludge receiver (44) includes a beach device (42) with an inclined upper surface (40), and a belt device (34) that moves a series of scrapers (32) along the surface of the water and along the beach device into the sludge discharge. Each scraper includes a flap of resilient material which is bent as it scrapes along the inclined beach surface.

Abstract: A sludge processor is provided which enables rapid disassembly and reassembly for changing between a sludge thickener configuration and a press configuration, and for enabling rapid disassembly for cleaning in the press configuration. The processor includes a frame with opposite sides and roller-holding bearing devices at the opposite sides for holding rollers about which a belt extends past a sludge dewatering region. The bearing devices can be arranged in a first configuration (FIG. 2) wherein the belt (12A) extends in an even path, and a second configuration (FIG. 1) wherein the belt extends in a tightly convoluted path so it and material thereon is squeezed between adjacent rollers. The bearing devices (50, FIG. 4) are releasably mounted to the frame sides to enable rapid conversion, and to enable rapid removal of the rollers for cleaning the processor when used in the second configuration.