WO1997034677A1 - Clarificateur de liquides a contre-courant - Google Patents

Clarificateur de liquides a contre-courant Download PDF

Info

Publication number
WO1997034677A1
WO1997034677A1 PCT/AU1997/000159 AU9700159W WO9734677A1 WO 1997034677 A1 WO1997034677 A1 WO 1997034677A1 AU 9700159 W AU9700159 W AU 9700159W WO 9734677 A1 WO9734677 A1 WO 9734677A1
Authority
WO
WIPO (PCT)
Prior art keywords
conduit
water
liquid
high pressure
clarifier
Prior art date
Application number
PCT/AU1997/000159
Other languages
English (en)
Inventor
William Rodgers
Original Assignee
William Rodgers
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by William Rodgers filed Critical William Rodgers
Priority to AU19169/97A priority Critical patent/AU1916997A/en
Publication of WO1997034677A1 publication Critical patent/WO1997034677A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D3/00—Differential sedimentation
    • B03D3/06—Flocculation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/0205—Separation of non-miscible liquids by gas bubbles or moving solids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/0208—Separation of non-miscible liquids by sedimentation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/0208—Separation of non-miscible liquids by sedimentation
    • B01D17/0214—Separation of non-miscible liquids by sedimentation with removal of one of the phases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/0217—Separation of non-miscible liquids by centrifugal force
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/04—Breaking emulsions
    • B01D17/041—Breaking emulsions with moving devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/04—Breaking emulsions
    • B01D17/047—Breaking emulsions with separation aids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/08—Thickening liquid suspensions by filtration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/12—Auxiliary equipment particularly adapted for use with liquid-separating apparatus, e.g. control circuits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/0003—Making of sedimentation devices, structural details thereof, e.g. prefabricated parts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/0012—Settling tanks making use of filters, e.g. by floating layers of particulate material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/0027—Floating sedimentation devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/02—Settling tanks with single outlets for the separated liquid
    • B01D21/08—Settling tanks with single outlets for the separated liquid provided with flocculating compartments
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B01D21/2405—Feed mechanisms for settling tanks
    • B01D21/2411—Feed mechanisms for settling tanks having a tangential inlet
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B01D21/2444—Discharge mechanisms for the classified liquid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B01D21/245—Discharge mechanisms for the sediments
    • B01D21/2461—Positive-displacement pumps; Screw feeders; Trough conveyors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B01D21/2488—Feed or discharge mechanisms for settling tanks bringing about a partial recirculation of the liquid, e.g. for introducing chemical aids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/26—Separation of sediment aided by centrifugal force or centripetal force
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/26—Separation of sediment aided by centrifugal force or centripetal force
    • B01D21/267—Separation of sediment aided by centrifugal force or centripetal force by using a cyclone
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/30—Control equipment
    • B01D21/34—Controlling the feed distribution; Controlling the liquid level ; Control of process parameters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/1418—Flotation machines using centrifugal forces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/1431—Dissolved air flotation machines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/1443—Feed or discharge mechanisms for flotation tanks
    • B03D1/1468—Discharge mechanisms for the sediments
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/01—Separation of suspended solid particles from liquids by sedimentation using flocculating agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B01D21/2433—Discharge mechanisms for floating particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B01D21/245—Discharge mechanisms for the sediments
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B01D21/2494—Feed or discharge mechanisms for settling tanks provided with means for the removal of gas, e.g. noxious gas, air
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/30—Control equipment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/30—Control equipment
    • B01D21/305—Control of chemical properties of a component, e.g. control of pH
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/30—Control equipment
    • B01D21/32—Density control of clear liquid or sediment, e.g. optical control ; Control of physical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/02—Froth-flotation processes
    • B03D1/028—Control and monitoring of flotation processes; computer models therefor

Definitions

  • This invention relates to units for the clarification of liquids containing suspended solids such as, for example, industrial waste water, raw or partly treated sewage or other liquids polluted with unwanted particulate matter. More particularly, the invention is related to such units which operate on the flotation principle, that is to say by causing the particulate matter to rise to the liquid surface for removal.
  • Water clarification is conventionally effected, by clarifiers comprising a treatment tank or the like, by holding the influent in the tank or the like for sufficient time to allow the suspended solids to float to the surface or sink to the bottom. The floating or settled solids are removed and the clarified water is allowed or caused to flow from the tank.
  • the throughput capacity of such a clarifier is a function of the horizontal cross-sectional area of the tank and the migration (rising or sinking) velocity of the suspended particles. The clarifier throughput capacity increases with increase in that area and with increase in the migration velocity.
  • the area is, of course, determined by the tank dimensions and the migration velocities are increased by chemical treatment of the raw liquid to cause coagulation and flocculation of the solid particles into effectively larger particles, and, in the case of flotation type clarifiers, the introduction of dispersed gas bubbles for entrapment by the larger particles so as to reduce their density and promote their migration to the liquid surface.
  • the present invention is an improvement on the invention described and claimed in the specification of International patent application No. PCT/AU93/00566, in the name of the present applicant, entitled VORTEX FLOCCULATION OF SOLIDS SUSPENDED IN LIQUID in which chemically flocculated suspended solids in contact with a water stream with supersaturated dissolved air flows upwards as a vortex in an upright conduit of circular cross-section of increasing diameter in the upwards direction.
  • This arrangement causes decreasing velocity gradients in the liquid being treated as it flows through the conduit so that the suspended solids floes incorporating air bubbles grow and rise rapidly to the surface for removal from the flow.
  • An object of the present invention is to increase the efficiency of flotation type clarifiers by comparison with the clarifier of the said specification PCT/AU93/00566.
  • the invention achieves that object by causing the liquid being treated to flow through a body of already flocculated material to enable that body to function as a continually renewed filter medium whereby further flocculated material is trapped by, and is rapidly added to, the body for subsequent removal from the clarifier.
  • the invention achieves that object primarily by providing for the counter- flow of the influent liquid relative to the upwards migration of the flocculated material relative to the liquid flow and the maintenance of a steady state condition wherein material is removed from the bottom of the body of flocculated material at a rate substantially equal to the rate of addition of flocculated material to the body derived from the influent polluted liquid.
  • the invention consists in a liquid clarifier comprising a substantially upright conduit of which at least a part has a cross-sectional area which increases progressively with decrease in altitude, raw liquid inlet means opening into said conduit at an upper level for the introduction of raw liquid to be clarified into said conduit at said upper level, which raw liquid is burdened with suspended particulate material, a clarified liquid outlet means opening into the conduit at a lower level for the discharge of clarified liquid from the conduit at said lower level, and extending from said lower level to an outlet at a discharge level at least equal in altitude to that of said upper level, and a particulates outlet means exiting the conduit at an intermediate level for the discharge of accumulated particulate material.
  • the invention consists in a method of clarifying raw liquid burdened with suspended particulate material comprising the steps of introducing the raw liquid at an upper level into a downwardly extending conduit having a cross-section which progressively increases with fall in altitude, extracting clarified liquid from said conduit at a lower level, establishing a body of particulate material within said conduit, and maintaining said body by removing material from the bottom ofthe body at an intermediate level at a rate substantially equal to the rate at which particulate material in the incoming raw liquid is added to the body.
  • means are provided to treat the influent raw liquid with coagulating and/or flocculating agents and to introduce or produce a multitude of small gas bubbles within the conduit to effect flotation of the particulate material.
  • preferred embodiments of the method of the invention further comprise the steps of treating the raw liquid with coagulating and/or flocculating agents prior to entry into the conduit and the provision or production of a multitude of small gas bubbles within the conduit.
  • the influent liquid stream to be clarified enters a vertical conduit with a cross-sectional area increasing towards the bottom of the conduit.
  • the influent stream contains suspended material (solids or liquids) and air bubbles.
  • the velocity decreases and the suspended material and air bubbles rise relative to the water flow.
  • the rate of ris of this buoyant material equals that of descent of the liquid, it is no longer carried down by the liquid and accumulates as a bed at that level and the liquid stream perforce passes through the bed.
  • the liquid velocity increases through the bed and it moves down the conduit and increases in size to reach equilibrium at a larger conduit cross-section.
  • a material discharge duct is inserted into the conduit above the clarified liquid outlet.
  • the material may be removed at a rate which balances the rate of material addition by the influent liquid stream so that the lower limit of the material bed is stabilised, with a clarified liquid stream descending to the bottom of the conduit.
  • the bed acts as a particulate filter by collecting the incoming particles as they collide with those already in the bed.
  • Figure 1 is diagrammatic sectional view taken on a vertical centre plane of a clarifying unit according to the invention, with nothing shown behind the section plane.
  • Figure 2 is a view similar to figure 1 of a second clarifying unit according to the invention.
  • Figure 3 is a schematic diagram of a waste water treatment plant incorporating a clarifying unit according to either figure 1 or figure 2.
  • the clarifying unit illustrated by figure 1 comprises a vertical conduit 1 of which the major part has a cross-sectional area increasing in the downward direction, a raw water inlet 2 at the top of the conduit to admit water with suspended particles and fine air bubbles into the conduit 1 at an upper level, a clarified water outlet means 3 exiting from the bottom of the conduit 1 , and particulate outlet means 4 opening into the interior of the conduit 1 at an intermediate level therein.
  • the raw water inlet 2 is preferably tangential to the conduit 1 so as to induce a descending vortex in the conduit 1 and so ensure adequate mixing of the contents therein and effective entrapment of air bubbles in the floes as they form within the conduit.
  • An initial discharge means 14 with a scroll collector 15 is positioned to trap and remove any particularly large or heavy item in the incoming feed water as a result of such an item being flung into the scroll collector by centrifugal force resulting from the vortex motion.
  • the clarified water outlet means 3 comprise an under-flow weir 5, an annular collector duct 6, a riser pipe 7 extending to at least the altitude of the inlet 2 and an overflow discharge device 8 .
  • the clarified water outlet means 3 are configured so that the water level in the conduit 1 is higher than the inlet so that the conduit 1 is kept full as the water flows through it.
  • the particulates outlet 4 comprises a discharge tube 9 and an open mouthed collector bell 10.
  • the outlet 4 effects discharge of accumulated particulate material. Its upper end from which the separated material is discharged is above the water inlet.
  • the discharge tube 9 may extend to a variable speed extraction pump to enable the rate of withdrawal of particulate material from the conduit 1 to be kept substantially equal to the rate of input of particulate material with the raw water being treated at any one time.
  • a hopper shaped closure 13 for the bottom of the conduit, with an outlet 12 provides for the removal of any particularly dense particles which might settle into this lower part of the conduit.
  • the under-flow weir 5 constricts the flow of clarified water from the conduit 1 and ensures that the flow is uniform across the conduit.
  • Chemical dosing material and apparatus operating on the influent liquid before or immediately after it enters the conduit 1 to promote the flocculation of suspended particles.
  • Chemical dosing material and apparatus to render insoluble, organic materials such as protein which will then be incorporated into the floes.
  • a charge of low specific gravity material such as plastic or hollow beads may be introduced into the conduit, which will float at the top of the floating body of flocculated particulates to increase the filtering effect of the floating material.
  • the clarifying unit may act as an aerobic biological reactor in which bacteria may form a film on a buoyant medium suspended in the material bed.
  • the shed bio-film will add to the bulk of the material bed and be transported to the exit duct and removed from the water stream.
  • the level of he water outlet weir may be set so that the bed material flows by gravity from the apparatus at a level higher than the outlet weir
  • the material may be pumped from the exit duct at a rate controlled to regulate the lower limit of the material bed so that it is always above the inlet to the clear water outlet so that no material from the bed can be entrained into the water outlet flow.
  • the suspended solids may be removed from the conduit by pumping from the exit duct, the air vent and the bottom closure outlet until only clear water remain in the conduit.
  • the outlet weir may be returned to the inlet system until the material bed is established in a stable position to give the maximum filtering effect and clear water is flowing under the weir.
  • a turbidity meter of pH monitor may be inserted into the outlet water flow to detect any out-of-specification performance and control the return of this water for reprocessing.
  • Additional air bubbles may be admitted to the bottom section of the conduit both to extract any particles moving downwards from the material bed and return them to this bed and to increase the buoyancy of the material in the bed.
  • the axis of the conduit may be inclined at an angle to the vertical, provided it retains clear differences in altitude between it upper and lower ends.
  • a chemical dosing in a gaseous form utilising, for example, ozone, may be used to react with materials in solution and in suspension in the water. In this event the gaseous products of reaction will be retained in the material bed and discharged via the vent or the exhaust duct.
  • This counter flow clarifier may be used as a gas contact apparatus wherein the gas is introduced into the inlet stream as fine bubbles which are contacted with the water by the vigourous agitation in the volume of the conduit above the exit duct and the undissolved gas may be vented via this exit duct or the vent at the top.
  • this is applicable to a mixture of ozone and air so that the ozone is absorbed and reacts with the water and the air is separated and vented.
  • the floating material bed may be a chemical reactor with chemicals, solid liquid or gas added to the inlet so that chemical reactions take place as they enter the top of the material bed and the final products of the reactor are withdrawn in the exit duct. This is switched for phosphorous removal or water hardness adjustment.
  • This counter flow water clarifier with gas bubbles may be used to strip dissolved gasses from the water stream by introducing larger volumes of air bubbles with the inlet stream so that dissolved gasses come out of solution due to the particle pressure gradient at the water surface of the bubble. The gas is then removed with the bubbles and vented at the top or the exit duct.
  • the air bubbles in the inlet stream may be produced by the introduction of an air stream and the mechanical agitation of the water stream to produce small dispersed air bubbles throughout the inlet stream.
  • the air bubbles in the inlet stream may be produced by introducing an air stream into the water stream at high pressure so that the air dissolves until it reaches saturation at the high pressure after a sufficient contact time.
  • This high pressure stream is then expended to the ambient pressure of the inlet to the conduit so that the water stream is supersaturated with the dissolved air at this lower pressure.
  • This supersaturated air then comes out of solution and nucleates on the suspended particles and may be incorporated in floes formed by chemical coagulation and flocculation so that the floes become buoyant as described above.
  • the expansion from high pressure to ambient pressure may be accomplished by the flow through a fixed orifice or adjustable orifice or valve.
  • the expansion from high pressure to ambient pressure may be accomplished by the flow through a spring loaded pressure regulating valve which can be adjusted to the desired high pressure value.
  • the expansion from high pressure to ambient pressure may be accomplished by the flow through a hydroelectric turbine or generating machine where the desired high pressure value is maintained by the electrical energy withdrawn from the generator.
  • the dissolving of air in the high pressure water stream may be accomplished by feeding the air stream into the inlet of a pump so that the air is broken into small bubbles during the passage through the pump which then dissolve at the high pressure in the water exit from the pump.
  • the pump may be a centrifugal type or axial flow type, or a positive displacement type such as a progressive cavity helical rotor type.
  • the hydroelectric turbine may be any of the above types of machinery.
  • the air saturation and expansion may be accomplished by two similar progressive cavity pumps connected together hydraulically with the pressure generating pump running faster than the progressive expansion pump. In this event, the power generated by this second pump may be recovered as regenerated energy to reduce the power required to dissolve the air in the high pressure stream.
  • FIG 3 This last mentioned arrangement is illustrated by Figure 3, wherein an inlet stream containing the suspended material to be removed is delivered by the supply pump 21 to an inlet mixing tube 22 into which is dosed one or more chemicals from a supply 23 to promote coagulation of the suspended solids.
  • the inlet mixing tube is connected to the inlet of a clarifying unit 4 according to either figure 1 or figure 2.
  • the clarified water flows from the outlet 25 to a clarified water tank 26. From the clarified water tank a return stream flows via a regulating valve 27 to an air compression pump 28 with an air regulator and meter 29 feeding air into its inlet.
  • a high pressure air and water stream then passes into a dissolving tube 30 and then to an expansion pump 31 from which it flows as a stream of water supersaturated with air into the inlet mixing tube where it mixes with the inlet stream and the dissolved air attaches as micro bubbles to the suspended solids particles.
  • a second flocculant chemical 32 is dosed in so that the coagulated suspended solids with attached micro bubbles are gathered together to form small floes in the counter flow clarifier 24.
  • the rapid mixing due to the high energy vortex caused by the vortex generator ensures uniform distribution of the flocculant chemicals.
  • Valves 33 and 34 can be adjusted in conjunction with valve 27 so that either the clarified water from the tank 26 can be used for the dissolved air stream or the inlet stream can be divided so that part or the whole is used for the dissolved air stream or a mixture of clarified water and inlet water can be used for the dissolved air stream.
  • the air dissolving pump 28 is driven by a variable frequency generator 35 from the main electricity supply and control board 37 and the expansion pump 31 is also driven by a regenerative variable frequency drive 36.
  • pump 28 is driven faster than pump 31 and the difference in speed is regulated by a pressure feedback from the high pressure dissolving pipe to maintain the required pressure.
  • the power generated by the hydroelectric pressure drop in pump 31 is reduced as electrical power by the regenerator variable frequency generator 36.
  • the counter flow clarifier can be used with coagulant and flocculant dosing with dissolved air using either all or part of the inlet stream for aeration or a part of the clarified water as a return stream.
  • the power cost ofthe high pressure pumping for the dissolved air is minimised by the regenerative expansion through a hydroelectric generator.
  • the present invention may be used, for example, in any of the following applications.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biotechnology (AREA)
  • Biological Treatment Of Waste Water (AREA)
  • Physical Water Treatments (AREA)

Abstract

Appareil pour clarifier de l'eau brute contenant des matières particulaires en suspension, et comprenant un conduit vertical (1) dont les diamètres vont en augmentant, à partir d'une entrée d'eau brute, située au sommet, jusqu'à une sortie d'eau claire à la base. On ajoute à l'eau à l'entrée du conduit une dose de coagulant et/ou de floculant, et on l'aère au moyen de fines bulles d'air avant qu'elle n'entre dans le conduit. Les bulles se fixent aux flocons lorsque ceux-ci se forment dans la partie supérieure du conduit. Alors que le liquide descend le long du conduit, la vitesse d'écoulement décroît, ce qui permet aux flocons de flotter à contre-courant du courant d'eau et de former un corps flottant dans le conduit, qui fonctionne comme un milieu filtrant. De l'eau claire s'écoule hors du conduit sous un déversoir de courant inférieur et est remontée par un conduit de sortie jusqu'à un niveau qui assure que ce conduit sera toujours plein d'eau. Les matières accumulées sont extraites de la base du corps par un conduit de décharge coaxial à une vitesse pratiquement égale à la vitesse d'augmentation de matières nouvelles provenant de l'eau brute d'arrivée, de sorte que le système parvienne à un état stable.
PCT/AU1997/000159 1996-03-15 1997-03-12 Clarificateur de liquides a contre-courant WO1997034677A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU19169/97A AU1916997A (en) 1996-03-15 1997-03-12 Counter-flow liquid clarifier

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AUPN8667A AUPN866796A0 (en) 1996-03-15 1996-03-15 Counter flow water clarification with air bubbles
AUPN8667 1996-03-15

Publications (1)

Publication Number Publication Date
WO1997034677A1 true WO1997034677A1 (fr) 1997-09-25

Family

ID=3792980

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU1997/000159 WO1997034677A1 (fr) 1996-03-15 1997-03-12 Clarificateur de liquides a contre-courant

Country Status (3)

Country Link
AU (1) AUPN866796A0 (fr)
ID (1) ID16246A (fr)
WO (1) WO1997034677A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI679055B (zh) * 2018-03-28 2019-12-11 玉城隆 水中及水面之沉降物、懸浮物除去裝置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2241904A (en) * 1990-03-16 1991-09-18 Hydro Int Ltd Gravity separator
EP0566792A1 (fr) * 1992-04-24 1993-10-27 Hydro International Limited Séparateur
WO1994009908A1 (fr) * 1992-10-30 1994-05-11 William Rodgers Floculation tourbillonnaire de solide en suspension dans un liquide
US5451318A (en) * 1994-01-28 1995-09-19 Moorehead; Jack Solids separator boundary layer effect filtration system
WO1995025584A1 (fr) * 1994-03-24 1995-09-28 Gävle Galvan Tryckkärl Ab Cuve de melange ou de separation de milieux en ecoulement
US5587068A (en) * 1994-11-15 1996-12-24 United Technologies Corporation Multi-attitude deaerator for oil tank

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2241904A (en) * 1990-03-16 1991-09-18 Hydro Int Ltd Gravity separator
EP0566792A1 (fr) * 1992-04-24 1993-10-27 Hydro International Limited Séparateur
WO1994009908A1 (fr) * 1992-10-30 1994-05-11 William Rodgers Floculation tourbillonnaire de solide en suspension dans un liquide
US5451318A (en) * 1994-01-28 1995-09-19 Moorehead; Jack Solids separator boundary layer effect filtration system
WO1995025584A1 (fr) * 1994-03-24 1995-09-28 Gävle Galvan Tryckkärl Ab Cuve de melange ou de separation de milieux en ecoulement
US5587068A (en) * 1994-11-15 1996-12-24 United Technologies Corporation Multi-attitude deaerator for oil tank

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI679055B (zh) * 2018-03-28 2019-12-11 玉城隆 水中及水面之沉降物、懸浮物除去裝置

Also Published As

Publication number Publication date
AUPN866796A0 (en) 1996-04-04
ID16246A (id) 1997-09-11

Similar Documents

Publication Publication Date Title
US5382358A (en) Apparatus for dissolved air floatation and similar gas-liquid contacting operations
CA2266583C (fr) Systeme de traitement des eaux et des eaux usees avec recyclage interne
US7037432B2 (en) Buoyant media flotation
CN106007209B (zh) 一种石油炼油污水除油预处理工艺
KR100992430B1 (ko) 침전 장치 및 이를 포함하는 하ㆍ폐수 처리 장치
CN1318312C (zh) 含有悬浮物的液体尤其是水的净化方法及装置
KR100810334B1 (ko) 응집분리장치
JPS6139880B2 (fr)
KR100530772B1 (ko) 2차 하수처리장치 및 처리방법
WO2001060494A1 (fr) Flottaison par milieux flottants solides
CN103030229B (zh) 一种钢铁行业的含油废水处理装置及其处理方法
JP4246087B2 (ja) 含油廃水処理装置
EP0695719A1 (fr) Méthode et appareil pour la flottation par air dissous et opérations de contact gaz-liquide de même nature
US20030155306A1 (en) Apparatus and method for the treatment of a contaminated fluid
JPH04166280A (ja) 浮上分離サイクロン装置
EP1218295B1 (fr) Procede et equipement de purification d'un liquide
EP0625074B1 (fr) Floculation tourbillonnaire de solide en suspension dans un liquide
WO1997034677A1 (fr) Clarificateur de liquides a contre-courant
AU1916997A (en) Counter-flow liquid clarifier
JP2892604B2 (ja) 溶解空気浮選および同様な気液接触操作の為の方法と装置
US5792363A (en) Method for removing solids from a contaminated liquid
KR101045878B1 (ko) 상하수 고도 처리를 위한 고효율 하이브리드 침전지
CN218709814U (zh) 一种含油废水处理系统
KR200371017Y1 (ko) 오폐수 처리용 가압부상조
RU1792742C (ru) Установка дл флотации сточных вод

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE GH HU IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD AT

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: JP

Ref document number: 97532973

Format of ref document f/p: F

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

NENP Non-entry into the national phase

Ref country code: CA

122 Ep: pct application non-entry in european phase