Abstract: Improved methods apparatus are provided for introducing and entraining air into a waste liquid, thereby increasing the quantity of dissolved oxygen in the liquid to enhance the aerobic treatment process. A power driven propeller is preferably positioned at the discharge end of conical-shaped transition housing, and draws in air while waste water is controllably introduced to the transition housing from below the surface of the water. The housing upstream from the propeller is primarily an air chamber with incoming streams of water, while the housing downstream from the propeller is filled with waste water having minute entrained air bubbles. The water and entrained air are thus discharged downwardly, and the axis of the equipment preferably inclined to increase circulation in the waste water pond or tank. The techniques of the present invention have relatively low power requirements while substantially increasing gas concentration in the liquid.

Abstract: An aspirating aeration and liquid mixing apparatus is positioned in a body of water and includes a motor driven propeller positioned within an intake duct and driving water through a nozzle. A plenum with an air intake pipe extends about the nozzle. The nozzle has ports with ramps thereover to provide a constriction for aspiration. The ramps are spaced annually about the interior of the nozzle with channels between the ramps. As water passes through the nozzle, a low pressure zone is created immediately downstream of the constriction to draw air through the ports, the plenum and the air intake pipe for aeration of the water. Large size materials which could otherwise clog at the constriction pass through the channels substantially unimpeded.

Abstract: In order to inject oxygen into a liquid, for example, sewage, the installation is provided with an aerating system (2) that is arranged in an aerating basin (1).In order to improve the oxygen injection rate per kilowatt of driving force the aerating system (2) that is connected with a pump (3) in the manner of a water jet pump, the flow cross-section of which, in its air intake area, can be varied so as to change the oxygen injection rate. To this end, the diffusor stage (8) of the aeration system (2) extends along a conical surface. The hollow-configured conical diffusor inner portion (13) is arranged, together with a surface aeration impellor (16), on a common drive shaft (14), and can be moved along its longitudinal axis (15).

Abstract: The invention relates to a disperser for a flotation system, in which the stabilizer plates are provided with holes and are offset by a specific angle against the direction of rotation of the agitator relative to a substantially radial position with respect to the agitator. By this arrangement of the stabilizer plates a significant improvement in the selectivity is achieved, particularly in the case of materials which are difficult to prepare.

Abstract: A system for dissolution-purification of Zn-containing materials which comprises a dissolving means for dissolving the Zn-containing materials and an ion-exchanging means for separating heavy metal ions included in the solution resulting from the dissolving means. In these means, the liquid or slurry to be treated is subjected to the dissolution and ion-exchanging operation countercurrently and the treatment residue including impurities is separated from the liquid or slurry to be treated so as not to contaminate the liquid or slurry with impurities and to improve the solubility.

Abstract: In a sewage treatment system having a series of generally concentric, ring-like treatment tanks, a siphoning head used to withdraw sludge from the bottom of the clarifying tank is propelled slowly and smoothly through its tank by the moving current of sewage in an adjacent tank. Overhead bridge structure supporting the siphoning head in the clarifying tank also overhangs the next adjacent tank and supports a depending baffle which is impinged by the flowing sewage in the adjacent tank. The baffle is positioned closely adjacent the wall between the two tanks such that eddy currents set up in the vicinity of the baffle as the latter is acted upon by the flowing sewage have the effect of entering transfer passages between the two tanks to clean out clogging debris and grease.

Abstract: A mobile water treatment plant capable of handling a high volume of sewage confined within the dimensions of a conventional truck-hauled container comprises:(1) a screen to separate gross solids from liquids;(2) a holding chamber between features 1 and 2 in which the liquid is aerated;(3) a flocculating chamber for the liquid;(4) a lamellar separator (bottom fed with intermediate auxillary lamellae extending 1/2 to 1/3 of the length of the main lamellae); and(5) treatment of the water from the lamellar separator with "activated oxygen" as described and claimed in U.S. Pat. No. 4,214,962.A preferred subsidiary feature is to recycle a controlled amount of the sludge separated at point 1 to the holding tank.

Abstract: An apparatus for introducing a gas into a liquid comprising a container, at least one vertical conduit in fluid communication with the container, the conduit having therein at least one mixer assembly for breaking up gas bubbles into bubbles having small diameters, and a means for introducing a gas into the conduit at a point below the mixer assembly, the mixer assembly comprising at least two freely rotating turbines which are spaced apart axially and have different direction or speed of rotation.

Abstract: A horizontal mixing aerator rides on a upright mast or beam for submersion in a body of liquid such as a sewage equalization basin, oxidation ditch or sludge holding tank. The aerator has a submersible mixer motor driving a propeller which is mounted to the beam by a slidable bracket arrangement for height adjustment. The bracket is also swingably mounted to the beam for adjustment of the vertical plane angle and the beam is rotatable for azimuth changes in the direction of liquid flow. A lower bracket stop includes vibration reducing elements. An upper azimuth lock also includes vibration reducing elements. The locking parts have a high co-efficient of friction.

Abstract: A surface-aeration rotor is provided with a carrier-part connected to a vertical drive-shaft. Secured adjustably to the carrier-part are several liquid-conveying units each consisting of a scoop and two flow-guiding walls. In order to improve the oxygen-input performance per kilowatt of rotor-drive power, the liquid-conveying units are designed in such a manner that the scoops are disposed in a plane which is twisted and which is curved in the direciton of rotation of the rotor, whereby the jets of liquid emerge from the rotor standing on edge.

Abstract: A method and apparatus for distributing a water purifying chemical, particularly a flocculating-agent concentrate, throughout a stream of water to be purified. In accordance with the method, the concentrate is introduced into the stream of water transversally to its direction of flow under the action of rotational motion, to achieve a distribution time of at most one second.

Abstract: A device based on rotating surfaces for promoting highly efficient molecular diffusive transfer between gases and liquids is described. Said transfer is achieved by generating a thin film of liquid which flows on a rotating surface, thereby exposing a large area of flowing liquid to the gaseous phase. This device is especially useful in promoting efficient molecular transfer of gases with low solubility in the liquid, e.g., oxygen into an aqueous phase in conventional aerobic fermentation vessels. The principle of this system can be employed in the reverse direction of transfer, for gases leaving the liquid phase, such as occurs in stripping, defoaming and deodorization. Of special value is the prevention of foaming, a common problem in the operation of conventional fermentation processes which occurs as the molecular transfer takes place.

Abstract: Device and method for cleaning waste water, wherein the waste water (19) and oxygen gas (31) are flowing in opposite directions through a cylindrical multireactor (20) having a central rotatable pipe (24), the multireactor comprising a number of bioreactors and at least one separation chamber (75). The average pressure difference between two successive bioreactors is at most seven meter water column. The bioreactors are separated from each other by stationary walls (40, 41, 48, 55, 60), and each bioreactor has its own mixing device (50) for mixing waste water and oxygen gas.

Abstract: An improved process and apparatus for continuously treating sewage wastewater by chemical oxidation of the contaminates and characterized by a high degree of oxygen absorption and utilization. An enclosed vessel continuously receives liquid wastewater at one end thereof to define a liquid level and the treated sewage is continuously removed from the other end to maintain the liquid level. Oxygen gas in the form of a mixture of O.sub.2 and O.sub.3 is introduced under pressure into the vessel, while pressurizing the vessel and creating an oxygen-rich atmosphere in an upper portion of the vessel, to chemically treat the wastewater through absorption of the oxygen by the wastewater.

Abstract: Apparatus for treating waste water by the solids contact aerobic biological treatment process comprises a clarifier and a reaction basin in liquid communication with one another. In one embodiment, the reaction basin has an aerator which also circulates liquid through the clarifier by way of pipes arranged to collect liquid from the surface of the reaction basin and deliver it to a location adjacent a back wall of the clarifier. The clarifier has a bottom wall which slopes towards the reaction basin. Sludge particles in the liquid settle out in the clarifier and liquid discharged from the pipes flushes the settled biological sludge back into the aeration section of the reaction basin. In another embodiment the clarifier and reaction basin together form an oxidation ditch defining a closed loop. An aeration device continuously circulates liquid around the loop and through the clarifier.

Abstract: The present invention provides an apparatus for generating gas bubbles in a liquid. The bubbles, which are uniform in size and on the order of approximately 100 micrometers in diameter or less, enhance the efficiency of gas transfer to the liquid. The apparatus includes at least one rotatable member, in the shape of a disc or ring, which is wettable by the liquid and rotatable therein at an edge velocity of at least 70 feet per second. The upper surface of the rotatable member is parallel to, and spaced from, a stationary plate to form a shear zone. Gas, or some other fluid, is supplied proximate the upper surface of the rotatable circular member to form the bubbles. Optimized relationships between the radius of the disc or ring and its speed of rotation are disclosed to enhance the efficiency of operation of the apparatus.

Abstract: A process for operating a total barrier oxidation ditch to provide concentrated power input per unit volume of the downwardly pumped liquor-air mixture and high mixing turbulence at maximum contact depth and hydrostatic pressure.

Abstract: A waste water treatment system including a vessel having a closed loop flow path, a bottom and a wall. A clarifier is mounted on the vessel wall within the vessel and includes a clarifier wall which is elongated in the direction of the flow path and is relatively narrowly spaced from the vessel wall. A clarifier wall extends from the bottom to a location above the intended level of waste water to define a clarifying chamber that is relatively narrow. Inlets may be located along the length of the clarifier wall and the bottom wall of the clarifying chamber may be provided with sludge outlets.

Abstract: An aerobic sewage digestion system has a tank including a treatment chamber 16 with a floor, sides, and a top, a sewage inlet into the treatment chamber and an access port means 19 at the top of the treatment chamber located centrally thereof. An agitating and aerating unit, suspended from the access port, includes an elongated generally cylindrical housing 22 having open ends and means 47 for supporting the housing from the access port in a vertical orientation within a pool of sewage contained in the treatment chamber, the housing being in predetermined spaced relation to the floor of the treatment chamber. An electric drive motor 25 having a closed casing is mounted within the housing with its rotatable output shaft 28 extending upwardly through the casing, and a motor mounting plate 26 fastened between the housing and the motor casing.

Abstract: Waste matter contained in a liquid is removed therefrom by introducing the liquid into a cell and introducing gas into the liquid to float waste matter to the liquid surface in the form of a floating scum. Gas nozzles situated adjacent the liquid surface are oriented to eject streams of pressurized gas across the liquid surface to blow scum into a waste outlet disposed adjacent the liquid surface. The nozzles are vertically adjustable to conform to different liquid surface levels.

Abstract: Mixing systems for liquids having fibers suspended therein wherein the fibers tenaciously adhere to and accumulate on the leading edge of the impeller, thereby increasing the drag of the liquid on the impeller as it rotates and the consequent increase in the power required to rotate the impeller. Axial flow of the liquid in a tank is produced by the impeller within a draft tube. The leading edge of the blades of the impeller are inclined with respect to radial lines extending from the axis of rotation of the impeller beyond the angle of repose of the fibers on the leading edge. Also, the coefficient of friction of the portion of the impeller, extending from the leading edge toward the trailing edge thereof, to which the fibers adhere is reduced by providing the surface thereof with a low coefficient of friction material.

Abstract: A method for directing a desired amount of gas below the liquid surface in a solution reactor, to mix the bubbles as effectively as possible with a suspension of a pulverous solid and a liquid, and to produce in the mixed gas-liquid-solid suspension a strong, suspension-maintaining flow field which is downward in the center of the reactor and upward along its sides, is disclosed. A so-called gls-mixer according to the invention consists of a circular plate fitted at the lower end of a rotating shaft suspended by its upper end, vertical dispersion blades situated radially at the edges of the circular plate, and baffles attached to the dispersion blades by means of arms. An upwardly directed gas-feeding conduit is fitted at the bottom of the reactor, and from this conduit the gas jet discharges to the center point of the circular plate.

Abstract: A process is described for pumping and aerating the mixed liquor within the endless channel of an oxidation ditch by using a pump/aerator to form an aerobic zone which has a selectively located planar end, where an anoxic zone begins, and within which biological nitrification of NH.sub.3 -N occurs. A pump/circulator, to which inflowing raw wastewater and return sludge are fed, is located approximately at this planar end to provide point-source mixing of the wastewater and return sludge, whereby the five-day biological oxygen demand of the wastewater is oxidized within both the aerobic and the anoxic zones and the nitrate ions formed within the aerobic zone are denitrified within the anoxic zone. Finally, an oxygen-deficient zone, wherein the mixed liquor is deficient in both dissolved oxygen and NO.sub.3.sup.- and NO.sub.2.sup.- anions and is ready for luxury uptake of oxygen within the pump/aerator, is dependably provided at the end of the anoxic zone.

Abstract: A dual baffle pump/aerator assembly comprising a concave intake baffle which is disposed upon the floor of an endless channel of an oxidation ditch to intercept the flow of mixed liquor within the channel. A horizontal barrier having aeration means associated therewith is disposed above and attached to the intake baffle. A concave discharge baffle is disposed above and attached to the horizontal barrier.

Abstract: Apparatus for mixing air with liquid, an aerator or oxygenator, comprises a motor or other power drive generally mounted in vertical position on a floating or a fixed structure, the motor having a shaft extending downwards through an opening in the center area of the float or fixed structure and bearing on its lower part a screw pump portion located in a cylindrical volute section just below the water level. When the apparatus is operating, the waste-water is sucked by means of the screw pump from the bottom of the body of liquid at which the apparatus is positioned and is pushed upwards in order to be diffused by means of a centrifugal impeller having outwardly curved blades, at least one of which extends downward to merge with a spiral shaped portion of a blade on the screw pump.

Abstract: An improved, self-cleaning, bidirectionally shiftable liquid contacting device is provided which serves to give enhanced aeration and mixing of liquids such as sewage water at a relatively low cost in terms of horsepower input. The device preferably includes a rotatable, flat, annular plate provided with oppositely projecting, circumferentially spaced, radially oriented rows of liquid-contacting elements strategically located and configured for maximum effectiveness. Each element is in the form of a flat-topped, solid body presenting a pair of elongated, opposed, inclined, converging, concave faces, with the axes of the respective concavities being transverse relative to one another. As the plate is rotated, the leading concave face gives excellent mixing and lateral liquid diversion, whereas at the trailing concave face, a suction action serves to draw air deeply into the liquid for subsequent release and aeration.

Abstract: A horizontal-axis aerator for use in a waste water purification system includes a cylinder having a horizontal axis, a first series of parallel blades on the surface of the cylinder and extending in directions nonparallel to the axis, and a second series of parallel blades on the surface of the cylinder and extending in directions nonparallel to the axis. The directions of the first series of blades are opposite to the directions of the second series of blades, with respect to the axis. The first and second series of blades intersect each other, such that upon the aerator being partially immersed in a body of waste water to be treated and being rotated therein, at any rotational position of the aerator about the axis, a constant portion of the total blade length of all of the blades of the aerator will be immersed in the waste water.

Abstract: A mixing-control apparatus for continuously moving mixed liquor having translational-flow momentum within an endless channel of a closed-circuit oxidation ditch, conserves at least of the portion of the momentum by enabling induced flow of the mixed liquor through adjustable openings in the barrier.

Abstract: The invention relates to an apparatus for the treatment of liquids, in particular for the biological purification of household sewage and/or industrial sewages containing organic contaminations, furtheron for the aeration and/or sedimentation of liquids. In the circular, quadratic or elongated oblong basin receiving the liquid a path recurring in itself is formed by means of one or more partition walls. For moving the liquid in a horizontal and/or horizontal and vertical direction propellers and/or rotors with a horizontal and/or vertical axle are used.For the aeration of the liquid one or more aerators with a horizontal or vertical axle and/or one or more fixed air blowers are applied.In sense of the invention one or more secondary sedimentators in a longitudinal arrangement or with a circular top-view, provided with oblique lamellae, are connected directly to the object or are assembled therewith.

Abstract: In aerobic wastewater treatment systems, such as sewage treatment, liquid in a channel spanned by a liquid-tight barrier is moved past the barrier by a liquid-gas contact pump, thus dissolving a gas in the liquid and creating a differential head that provides flow energy for moving the liquid in plug-type flow through the channel, which is preferably a continuous-flow pipeline or a circuit-flow oxidation ditch, without energy-wasteful vertical circulation. The barrier further provides a structure for mounting submerged static aerators or a draft tube, in combination with a surface aerator, such as a submerged turbine or surface-disposed impeller aerator, as the liquid-gas contact pump. The barrier is disposed at sufficient depth, when combined with static aerators or when telescopically attached to the draft tube of a floating surface aerator, to enable the liquid level to be selectively varied so that flow equalization to an oxidation ditch and wastewater storage therewithin are provided.

Abstract: A waste digestion unit which comprises a container, a waste inlet into the container, an outlet from the container for digested waste, a gas bleed outlet from the container and a stirrer for stirring the contents of the container. The inlet, waste outlet, bleed outlet and stirrer are arranged so that the container can be mounted in position and partially filled with waste to a level defined by the waste outlet to provide a gas space above the waste. In this position of the container the bleed outlet is above the waste level and, the inlet discharges into the container below the waste level. The stirrer is capable of stirring the waste at said waste level and below said waste level.

Abstract: A fluid diffuser for dispersing a gas or liquid into a body of receiving liquid in which it is immersed. The diffuser includes a rotatable shaft, a thin disk-like member mounted for rotation on the shaft, and an annular ring positioned adjacent the outer perimeter of the disk-like member. At least one of the top and bottom walls of the annular ring is porous. These top and bottom walls define a fluid plenum, into which gas or liquid under pressure is introduced to be emitted from the plenum as small, nascent fluid spheroids on the surface of the annular ring. The boundary layer flow from rotation of the disk-like member within the body of receiving liquid shears fine gas bubbles or liquid particles from the foraminous surface or surfaces of the annular ring. The annular ring may be fixed, or rotatable in the opposite annular direction from the rotation of the disk. Impeller blades may be mounted on the top and/or bottom surfaces of the rotatable disk.

Abstract: A barriered pump/aerator, for continuously moving and aerating mixed liquor having translational-flow momentum within an endless channel of a barrier oxidation ditch, conserves at least a portion of the momentum by enabling induced flow of the mixed liquor past the barrier. In one embodiment, the induced flow passes through a discharge slot which contains a plurality of jet aerators. In another embodiment, the induced flow passes through a trough formed in the bottom of the endless channel past an inclined baffle. In a third embodiment, the induced flow passes through a tubular passage having a plurality of jet aerators disposed therein.

Abstract: Aeration apparatus for aerating a liquid to be treated in an aeration tank. The aeration apparatus has an impeller by means of which the liquid is displaced through an annular discharge passage defined between an outer casing and an inner casing disposed coaxially in the outer casing at a predetermined distance from the latter. The outlet end of the annular discharge passage opens in a substantially horizontal direction and radially outwardly. A gas supplying device provided in the annular discharge passage is adapted to supply an oxygen-containing gas to the liquid flowing in the annular passage.

Abstract: This invention relates to flocculation apparatus for the purification of liquids, particularly water, wherein provision is made for initial vigorous mixing of the coagulants in the liquid followed by a gradually diminishing agitation of the liquid and flocculent to provide proper flocculation; the apparatus comprising a circular flat bottomed chamber, a central circular well having openings through its wall spaced apart circumferentially and vertically, a plurality of radially extending rotatable arms supported above the chamber, each arm carrying downwardly depending blades spaced apart along the length of the arms and positioned to intersperse with a plurality of series of vertical fixed blades extending radially from the well, and upwardly from the floor of the chamber, the blades extending substantially the full depth of the chamber, at least one feed chamber in communication with the chamber through an opening in the wall thereof, means for rotating the arms and an outlet from the bottom of the well lead

Abstract: A waste water treatment system including an oxidation vessel which receives waste water and has at least one wall and is adapted to introduce oxygen into the waste water contained therein. A clarifier is mounted on the wall at the outlet from the vessel and is narrow in comparison to the vessel. The clarifier includes generally vertical end walls and an imperforate elongated generally vertical sidewall defining upper and lower ends of the clarifier. The lower end of the clarifier is opened to provide for admission of waste water into the clarifier and an apertured plate extends along the length of the clarifier at the upper end and is hydraulically interposed between the clarifier and the vessel outlet.

Abstract: An elongated casing is provided and is closed at one end. A fluid pressure actuated elongated internal vibrator of the type including an internal fluid pressure driven eccentric weight orbital about an axis extending centrally longitudinally through the vibrator is provided and is loosely telescoped into the other end of the casing. The other casing end is tightly closed about the adjacent end of the internal vibrator and the interior of the casing is filled with a hard fluent aggregate disposed about the vibrator and a pair of annular members are tightly mounted upon and extend about longitudinally spaced portions of the vibrator and include outer peripheral portions spaced inward of the inner surfaces of the casing. The vibrator and its surrounding aggregate filled casing may be suspended in a tank containing well effluent of the type comprising water and oil and having gas suspended therein.

Abstract: Apparatus for mixing air with liquid (aerator or oxygenator) comprises a motor or other power drive generally mounted in vertical position on a float or a fixed structure, the motor having a shaft extending downwards through an opening in the center area of the float or fixed structure and bearing on its lower part a propeller located in a cylindrical volute section just underneath the waterlevel. When the apparatus is operating, the waste-water is sucked by means of the propeller from the bottom of the body of liquid on which the apparatus is floating and pushed upwards in order to be diffused by means of a rotating diffusion head in the shape of a paddle-wheel. This feature increases efficiency of the installation, allowing the velocity of the fluid leaving the propeller to be kept as low as possible and the dimensions of intake volute and propeller to be increased.

Abstract: The rotary surface aeration device used to rotate and aerate sewage is provided with a carrying part connected to a vertically running drive axle. A plurality of liquid transporting units also fastened to the carrying part.In order to improve the oxygen input, the liquid transporting units, which are adjacent to each other viewed in the circumferential direction of the rotary aerating device, have different jet exiting speeds. This is achieved by giving the scoop outlet edges of these liquid transporting units, which are adjacent to each other, a different distance (d, d') from the drive axle of the rotary aeration device. The liquid transporting units are arranged and constructed in such a way that the liquid jets of at least two liquid transporting units, which are adjacent viewed in the circumferential direction of the rotary aeration device, exiting from said units during the operation of the rotary aeration device strike each other before reentering into the liquid to be aerated.

Abstract: A hydraulically powered mixing aerator rides on an upright beam member for submersion in a body of water such as an equalization basin, oxidation ditch or sludge holding tank used in sewage treatment plants. The aerator employs a submersible, hydraulically powered mixing motor driving a propeller which is mounted on the beam member by a slidable bracket for height adjustment. The beam member is swingably supported to allow adjustment of the vertical plane angle. Because the beam member is also mounted for rotation, substantially any attitude or position of the mixer can be selected for creating an efficient flow pattern within the body of water. The speed at which the propeller is rotated, and therefore, the rate at which the water is circulated and aerated, is selectively adjustable. The hydraulically driven motor provides for a low speed and high torque rotation of the propeller without the use of a reduction gear.

Abstract: In a process for mixing a gas and a liquid in an apparatus having an axial flow down-pumping impeller located in a draft tube and preceded by a first baffle wherein a vortex and turbulence are created and gas is drawn into the vortex, the improvement comprising providing liquid velocity of at least one foot per second, increasing the turbulence, providing a second baffle below the impeller, and a high shear zone between impeller and the second baffle.

Abstract: An apparatus for aerating a body of stagnant water to neutralize the pollutants therein. The apparatus draws fresh ambient air above the surface of the water and forcibly disburses the air under the surface into the body of water for oxidation purposes. The apparatus comprises a hollow rotatable cylindrical casing provided with a helical vane mounted on one end of the casing. A series of holes in the casing wall adjacent the vane creates regions of sub-atmospheric pressure in the vicinity of the holes when the cylinder is rotating; thus drawing air from the interior of the casing and, by a scooping action, forcing the air generally radially outwardly and below the surface of and into the body of water. The cylinder is driven by a motor. The helical vanes may be formed of torroidal disc or washer that is cut and spread apart axially and secured to cylindrical casing.

Abstract: A pressurized aeration tank is provided which comprises an inner barrel arranged on the tank axis and an axial-flow impeller of optimum characteristics mounted therein, the inner barrel and the outer barrel or body portion of the tank being particularly proportioned and arranged relative to each other to define in the tank a circuitous flow passage of minimal total resistance loss. With this tank structure, a highly improved plant efficiency of BOD removal is readily obtainable with the use of concentrated activated sludge and aerobic microorganisms, mainly of the Opercularia group, in a specified range of tank pressure.

Abstract: A flotation separation cell is disclosed having a rotor-stator pump assembly wherein a rotor body comprises integrally formed hub, blade and top plate members. These members form a gas chamber in an upper sector of the rotor. The blades are curvilinear and of parabolic or vortex shape. A gas stream which is conveyed to the gas chamber is discharged from the gas chamber in a transverse direction and flows in gas pockets along surfaces of moving blades for dispersion in a slurry.

Abstract: A method for removing the excess sodium and byproducts of reaction which occur during the destruction of PCBs from oil. A predetermined quantity of water is mixed with the decontaminated oil and the byproducts, which include sodium chloride and polyphenyl polymer, to form sodium chloride and sodium hydroxide. Centrifuging removes most of the oil from the remaining aqueous mixture which then is agitated and treated with carbon dioxide gas to form less hazardous sodium carbonate and sodium bicarbonate. Any excess carbon dioxide gas is vented to the atmosphere and the sodium carbonate and sodium bicarbonate is collected into containers for disposal. Small amounts of oil remaining in the aqueous waste mixture that is discharged from the centrifuge is decanted from the remaining material in a waste separator due to its lighter specific gravity. A pump intermittently injects waste from the waste separator into a converter where it reacts with the carbon dioxide gas.

Abstract: A low cost automatic system for making up a chemical solution for use in a water treatment facility includes a mixing tank having high and low liquid level switches disposed therein. A water supply line having a remotely-controlled solenoid valve supplies water to the mixing tank. A pressure regulator in the water supply line maintains the water pressure in the line between about 5 pounds per square inch and 125 pounds per square inch. Water treatment chemicals are stored in a supply tank and are fed by a metering pump to the mixing tank through a supply line. An electrical control circuit is responsive to the high and low liquid level switches in the tank. The control circuit operates the solenoid valve in the water supply line and the chemical pump as required to maintain a supply of chemical solution in the mixing tank.

Abstract: An aerator (2) comprises a motor (10) having a propeller (18). A slotted cage (30) surrounds propeller (18) and prevents marine life from being drawn in to propeller (18). Liquid will be ejected from propeller (18) in a horizontally traveling stream which stream is oxygenated by a draft tube (48) having a lower end located adjacent propeller (18). Slotted cage (30) is carried on a support rod (68) to form the structure for supporting aerator (2) in tank (4). Cage (30) prevents marine life from being drawn into the propeller (18) as it is driven.

Abstract: An aerator for aerating a body of water such as a catfish pond, or the like, operates by stirring the water in the body of water. A paddlewheel having movable paddles stirs the water near the surface to mix oxygen-rich surface water with oxygen-deficient deep water.

Abstract: A sewage ventilating basin of a sewage treatment plant comprises a sewage container which is sunk into the ground and into which project three vertical tubes which connect the surface water of the container with the deepest water thereof. By means of feed pumps, a downwardly-directed flow is produced in the tubes so that the sewage in the container circulates upwardly and recirculates in the tubes. Disposed in each tube in the upper part thereof are devices for the fine-bubble introduction of a ventilating gas. The flow velocity of the sewage in the tube and directly below this upper part is higher than the uplift velocity of the gas bubbles being introduced into the flow at the same point. Since the gas is introduced into the sewage not in the bottom zone of the container but instead in the upper part of the tube, the gas pressure is lower than in the case of the direct introduction of the gas into the bottom zone, and also the energy expenditure is smaller with a high effectiveness of the ventilation.

Abstract: In a process for mixing a gas and a liquid in an apparatus having an axial flow down-pumping impeller located in a draft tube and preceded by a first baffle wherein a vortex and turbulence are created and gas is drawn into the vortex, the improvement comprising providing liquid velocity of at least one foot per second, increasing the turbulence, providing a second baffle below the impeller, and a high shear zone between impeller and the second baffle.