Abstract: A denitrification apparatus, for use in a wastewater treatment system having a mixed liquor source, is disclosed. The apparatus has at least two non-aerated continuous channels, connected in series. Wastewater flows from the mixed liquor source into the series of channels and then flows back into the mixed liquor source. In a preferred embodiment the inlets and outlets for each channel are arranged so that the flow into the channel is into the lower portion of the channel, and the flow from the channel is from the upper portion.

Abstract: In an extended aeration wastewater treatment system having wastewater flowing into a retention basin so as to form mixed liquor within the retention basin, the treated mixed liquor flowing out of retention basin through a retention basin exit line to an external clarifier, a mixed liquor wasting system is provided, comprising a thickener tank, having a sidewall and a bottom; a waste line having a first end and a second end, the first end fluidly connected to the retention basin by connection to the retention basin exit line, and the second end fluidly connected to the thickener tank; a first flow control device, such as a pump, for continuously removing a portion of the mixed liquor from the basin at a desired constant flow rate through the waste line, positioned in the waste line; a sludge removal line having a first end and a second end, the first end fluidly connected to the bottom of the thickener tank, and the second end fluidly connected to a sludge disposal system; a second flow control device, such as

Abstract: In an extended aeration wastewater treatment system having wastewater flowing into a retention basin so as to form mixed liquor within the retention basin, a mixed liquor wasting system is provided, comprising a thickener tank, having a sidewall and a bottom; a waste line having a first end and a second end, the first end fluidly connected to the retention basin, and the second end fluidly connected to the thickener tank; a first flow control device, such as a pump, for continuously removing a portion of the mixed liquor from the basin at a desired constant flow rate through the waste line, positioned in the waste line; a sludge removal line having a first end and a second end, the first end fluidly connected to the bottom of the thickener tank, and the second end fluidly connected to a sludge disposal system; a second flow control device, such as a pump, for removing a concentrated portion of the mixed liquor from the thickener tank, positioned in the sludge removal line; and a return line having a first end

Abstract: An oxidation ditch wastewater treatment and denitrification system is provided, comprising an oxidation ditch, including a central channel, having an inlet end, an outlet end, a bottom and two sidewalls; an aeration channel, having an inlet end fluidly connected to the outlet end of the central channel, an outlet end fluidly connected to the inlet end of the central channel, a bottom and two sidewalls; and a denitrification channel, having an inlet end fluidly connected to the outlet end of the central channel, an outlet end fluidly connected to the inlet end of the central channel, a bottom and two sidewalls; an aerator, positioned in the aeration channel; and at least one circulation device, positioned in the oxidation ditch and adapted to circulate wastewater from the inlet end of the central channel to the outlet end of the central channel, from the inlet end of the aeration channel to the outlet end of the aeration channel, and from the inlet end of the denitrification channel to the outlet end of the de

Abstract: An oxidation ditch for circulating a waste water stream and having a channel formed by a continuous vertical outside wall extending upward from a bottom and having at least one section shaped to form a curved area into which a vertical turbine is operatively positioned and by a partition wall also extending upward from the bottom and positioned inside the outside wall with one of its ends adjacent the vertical turbine, the improvement of which comprises a baffle positioned in the channel upstream of the vertical turbine to minimize the mixing of the upstream waste water with the backwash created by the vertical turbine.

Abstract: Operation of an intra-channel clarifier within a circulating sewage stream can be enhanced by flow adjusting vanes positioned within the sewage stream between the clarifier and channel wall, proximate to the clarifier sludge ports. In a preferred embodiment, the vanes are aligned perpendicular to the flow of the stream, on a vertical axis. The vanes are divided into an independently adjustable upper and lower portion which can be used to direct the sewage flow and alter the cross sectional area of the sewage stream in the vicinity of the clarifier. The rate at which sludge is removed from the clarifier is affected by the velocity of the sewage stream beneath the sludge ports as well as any turbulence or eddy currents which are produced.

Abstract: A skimmer system is provided for structures having a floor, two side walls and at least one open end, the structure being semi-submersibly positionable in a moving liquid stream. The skimmer system comprises at least one side trough having a bottom, an interior trough wall and an exterior trough wall. The exterior trough wall is coincident with the interior side of one side wall of the structure and is provided with at least one opening communicating betweeen the interior of the trough and the exterior of the structure. The interior trough wall is provided with at least one opening communicating between the interior of the trough and the interior of the structure.

Abstract: A turbulence control system is provided comprising a first baffle, fixedly connected across the interior of an intra-channel clarifier having side walls between the side walls near the point of entry of wastewater into the clarifier, the first baffle covering a desired portion of the cross-sectional flow area within the clairifier; and a second baffle, fixedly connected across the interior of the clarifier between the side walls downstream of the first baffle and covering a desired portion of the cross-sectional flow area left uncovered by the first baffle. The turbulence control system may also comprise at least one accumulation baffle, connected between the side walls and near the bottom of the clarifier, the accumulation baffle extending upward to a desired height within the clarifier, but not so high as to produce a flow velocity which would impede settlement of sludge within the clarifier.

Abstract: A filter for use in conjunction with an intrachannel clarifier is provided comprising an enclosure, positionable within a channel and connectible to an intrachannel clarifier, and having a floor and sides; a filter compartment fixed within the enclosure, and having sides, either connected to or coincidental with the sides of the enclosure and segregating the interior of the filter compartment from the remainder of the enclosure; a porous medium support, fixedly connected to the sides of the enclosure and positioned within the filter compartment; a bottom, below the medium support and fixedly connected to the sides of the filter compartment; a filter medium, positioned within the filter compartment above the medium support; a conduit, connecting between the interior of the filter compartment beneath the medium support and the interior of the enclosure; a liquid dispersion mechanism, positioned within the filter compartment above the filter medium, for receiving liquid from outside the enclosure and dispersing

Abstract: A side skimmer provided in a channel containing flowing liquid includes a skimmer mechanism and a skimmer drain. The skimmer mechanism includes a fixed portion secured in a hinge-like manner to one side of the channel and aligned with an obstruction located partially across the channel width, and a movable wing-like portion extending above and below the liquid surface. This mechanism selectively deflects the flow into the drain, and is movable between a closed position, which allows free flow between the mechanism in the channel side and the obstruction, and an open position between the fixed portion and the obstruction, which directs flow to the skimmer drain. The skimmer drain is vertically movable between a closed position above the liquid surface, and an open position just below the surface whereby floating matter is removed.

Abstract: A waste water stream is clarified by phase separation of a part of the stream in a clarifier positioned in an oxidation ditch, through the establishment of a head differential between the level of liquid in the clarifier and the level of liquid in the oxidation ditch.

Abstract: In an oxidation ditch process for clarifying a waste water stream employing a clarifier boat, a novel skimmer assembly is disclosed having a buoyant closing assembly to control the amount of surface fluid containing the bulk of the oils, greases, etc. in the waste water being removed from the clarifier.

Abstract: A process and apparatus for treatment of waste water is provided wherein a waste water clarifier is positioned in a waste water flow channel and having a body assembly with a bow section facing into and extending above the waste water currents, a stern section having a opening below the waste water level to allow waste water to enter the clarifier and, having a rear baffle extending between clarifier side walls and extending downward perpendicularly thereto and a second baffle extending partially between the clarifier side walls and extending downward and perpendicularly thereto, the bottom section having rows of tubular pipes extending at an angle downward therefrom with the pipe openings facing opposite the waste water flow, and an effluent launder fixedly positioned in the bow section.

Abstract: Used oil is rerefined by distillation and extraction with tetrahydrofurfuryl alcohol. In accordance with the process, used oil is rerefined by distillation to remove a volatile forecut followed by further distillation with recirculation provisions to obtain the desired fractions of lubricating oil products while reducing the vaporization temperature of the oil. The recycle effect tends to reduce coking and cracking while providing a greater recovery of lubricating oil products through the carrier effect of the light ends. After the desired fractions of lubricating oil have been obtained by the distillation phase of the process, tetrahydrofurfuryl alcohol is utilized in an extraction process to remove impurities remaining in the distilled oil. The tetrahydrofurfuryl alcohol-lube oil mixture is separated into a raffinate and extract stream for distilling and steam stripping the tetrahydrofurfuryl alcohol therefrom.

Abstract: Used oil is refined by distillation to remove a volatile forecut followed by further distillation with recirculation provisions to obtain the desired fractions of lubricating oil products while reducing the vaporization temperature of the oil. The recycle effect tends to reduce coking and cracking while providing a greater recovery of lubricating oil products through the carrier effect of the light ends.In one embodiment of the invention, a waste oil feedstock has water, gasoline and other similarly volatile components removed in a first stage evaporator (16). Heavier fuel, such as fuel oil is then removed in a second stage evaporator (28). A light lube oil fraction is then obtained by distillation with a third stage wiped-film evaporator (40). Finally, a heavy lube oil fraction is obtained by distillation of the bottoms from the evaporator (40) with a fourth-stage evaporator (64).