Abstract: A system is provided for removing accumulated oil from a basin. An endless belt for carrying oil is partially submerged in the basin and is driven and supported by a rotary drum. The rotary drum has an irregular surface for frictional cooperation with the belt and a spring-biased roller urges the belt against the irregular surface. The oil is scraped from the belt and directed away from the belt and basin. Means are also provided for wiping the underside of the drum surface.

Abstract: A circular dissolved gas flotation system is provided for increasing the loading rate with increasing size flotation basins. The dissolved gas flotation system includes a submerged annular release chamber located about the periphery of the flotation basin for peripherally introducing particle-carrying liquid and gas bubbles uniformly into the flotation basin. The release chamber defines a continuous slotted opening substantially about the length of the release chamber. The size of both the slotted opening and the cross-sectional area of the release chamber are reduced from the divider baffle to the splitter baffle to uniformly distribute the flow about the periphery of the flotation basin. The release chamber includes a divider baffle to split the input flow in opposite directions tangentially about the length of the release chamber, and a splitter baffle to prevent the two tangential flows from converging.

Abstract: A compact dissolved air floatation system is provided for very small flow, i.e., less than 20,000 gallons per day. The floatation system includes a vertical floatation column including a release well comprising an inverted, truncated cone with tangential inlet flow to prevent breakage of the bubbles. The floatation column also includes a clarified water outlet at the lower portion thereof, which water outlet comprises a pipe defining openings on its circumference and having a debris trap member fastened to the top of the pipe.