WO2005082788A1 - Procede d'elimination d'especes de fluorure - Google Patents

Procede d'elimination d'especes de fluorure Download PDF

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Publication number
WO2005082788A1
WO2005082788A1 PCT/AU2005/000293 AU2005000293W WO2005082788A1 WO 2005082788 A1 WO2005082788 A1 WO 2005082788A1 AU 2005000293 W AU2005000293 W AU 2005000293W WO 2005082788 A1 WO2005082788 A1 WO 2005082788A1
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Prior art keywords
wastewater
fluoride
electrocoagulation
species
cell
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PCT/AU2005/000293
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English (en)
Inventor
Brian Grigg
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Aquenox Pty Ltd
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Priority claimed from AU2004901018A external-priority patent/AU2004901018A0/en
Application filed by Aquenox Pty Ltd filed Critical Aquenox Pty Ltd
Publication of WO2005082788A1 publication Critical patent/WO2005082788A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • C02F1/004—Processes for the treatment of water whereby the filtration technique is of importance using large scale industrial sized filters
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/463—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrocoagulation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
    • C02F1/56—Macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/12—Halogens or halogen-containing compounds
    • C02F2101/14—Fluorine or fluorine-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • C02F2101/18—Cyanides
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/36—Organic compounds containing halogen
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/005—Processes using a programmable logic controller [PLC]
    • C02F2209/006—Processes using a programmable logic controller [PLC] comprising a software program or a logic diagram
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/06—Controlling or monitoring parameters in water treatment pH

Definitions

  • TITLE FLUORIDE SPECIES REMOVAL PROCESS FIELD OF INVENTION This invention is concerned with methods of removing contaminants from aqueous waste streams from industrial processes or from contaminated bodies of water.
  • the invention relates to a method of removing free and complex fluoride species from wastewater.
  • Many industrial processes produce wastewater effluents containing complex and free fluoride compounds.
  • the semi-conductor, aluminium, dental, chlorofluorocarbon, cannery and glass industries produce large amounts of fluoride-containing wastewater. Strict regulations have been implemented to dictate the discharge limits for fluoride in wastewater.
  • Removal of fluoride from wastewater is usually carried out by precipitation of fluoride ions using metal ions, reverse osmosis and ion exchange using cationic ion exchange resins.
  • US Patent No 6,210,589 describes a process for removing fluoride from water that comprises the steps of adding calcium, sodium and aluminium reagents to the wastewater in a fluidized bed crystallizer, and adding aluminium hydroxide to the wastewater in a second fluidized bed crystallizer. This process has a slow treatment rate, uses large volumes of expensive chemicals, is not suitable for treating large volumes of water and could not be used as a continuous treatment process.
  • US Patent No 5,910,251 describes a process for removing fluoride and other contaminants from large quantities of wastewater.
  • the wastewater is treated with a chemical coagulant and passed through a microfiltration membrane which physically separates the contaminants, in the form of precipitated particles, from the water. It is essential that the microfiltration membrane is frequently back-flushed to remove solids from the membrane surface. Coagulated particles of fluoride contaminants have a tendency to adhere to and clog microfiltration membranes which can result in unsatisfactory contaminant removal efficiency and significant down-time for cleaning or back-flushing of the membranes.
  • US Patent No 6,645,385 provides an apparatus and method for removing fluoride from wastewater.
  • the system comprises a single fluoride electrode for measuring the concentration of fluoride in the wastewater influent, a reaction tank for addition of calcium salts to the wastewater, and a filtration tank for removal of the precipitated fluoride formed in the reaction tank.
  • Measurement of the concentration of fluoride in the wastewater enables the optimal amount of calcium salts to be added to the wastewater for effective fluoride precipitation.
  • Disadvantages of this system include the use of costly chemicals and the inconvenience of cleaning the filters in the filtration tank. It is therefore an object of the invention to provide a process for removal of fluoride species from water that may alleviate the disadvantages over the prior art.
  • the invention provides a process to remove fluoride species from wastewater that comprises the steps of: (a) removing suspended solids from the wastewater; (b) adjusting the pH ofthe wastewater to fall within the range pH 4 - 8; (c) passing water through an electrocoagulation reaction chamber which comprises a plurality of reaction plates or electrodes disposed within said reaction chamber and spaced apart from each other, wherein said plates are manufactured from aluminium, and at least two of said plates are electrically connected to a power supply; and (d) separating solids from the wastewater.
  • the invention provides a process to remove fluoride and cyanide species from wastewater that comprises the sequential steps of: (i) removing fluoride species from the wastewater; and (ii) passing the wastewater through an electrocoagulation reaction chamber to remove cyanide species.
  • step (i) comprises the step of passing the wastewater through an initial electrocoagulation reaction chamber to remove fluoride species. More preferably, step (i) comprises the steps of the first aspect of the invention.
  • step (ii) comprises the steps of: (1) removing suspended solids from the wastewater; (2) adjusting the pH of the wastewater to fall within the range pH 6.0-8.5; (3) adjusting the conductivity of the wastewater to fall within the range 3500-4500 ⁇ S/cm; (4) passing the wastewater through the initial electrocoagulation reaction chamber which comprises a plurality of reaction plates or electrodes formed from stainless steel disposed within said reaction chamber and spaced apart from each other and at least two of said plates are electrically connected to a power supply; and (5) separating solids from the wastewater.
  • the process of the second aspect will be most useful for wastewater comprising both fluoride and cyanide species, such as wastewater produced by the aluminium industry.
  • step (2) the pH of the wastewater is adjusted to fall within the range pH 7.0 - 8.2.
  • step (3) the conductivity of the wastewater is adjusted to fall within the range 3500-4000 ⁇ S/cm.
  • the variables governing performance of the electrolytic reaction chamber in step (c) and step (4) which include voltage, amperage, number of electrically connected electrodes, flow rate and conductivity can be determined from the following relationships: (1) if the voltage, number of electrically-connected electrodes, and the flow rate are fixed, conductivity and amperage are variable; (2) if voltage, conductivity and flow rate are fixed, the number of electrically connected electrodes and amperage are variable; and (3) if the flow rate, conductivity and number of electrically connected electrodes are fixed the amperage and voltage are variables.
  • the electrocoagulation cell Prior to step (a) of the first and second aspects the wastewater may be obtained from an industrial process or any suitable contaminated water body such as ground water, a reservoir, spring, river, pool or other water body.
  • the electrocoagulation reaction chamber or cell used in the first or second aspect of the invention is part of a conventional electrocoagulation cell as described in International Patent Application WO 01/53568 or US Patent 6, 139,710.
  • direct current is applied to the reaction chamber.
  • DC direct current
  • the electrocoagulation cell is preferably orientated vertically so that the outlet conduit is located at the top of the reaction chamber and the inlet conduit is located at the bottom of the reaction chamber.
  • an electrolytic cell arranged horizontally such as described in, for example, WO 96/28389 or in US Patent No. 5,611 ,907.
  • the water will make a single pass or multiple passes through the electrolytic reaction chamber but it is also possible for the water to be circulated throughout the cell in a serpentine fashion in either a vertical or horizontal orientation.
  • the electrolysis cell may comprise any number of electrodes or reaction plates but at least three are used and two are electrically coupled to a power supply.
  • the total number of electrodes used can be calculated depending on the total wetted surface area of electrodes in the cell, the number of electrodes electrically connected to a power source, the gap between the electrodes, and the flow rate, conductivity and cell residence time of the solution.
  • each side of the electrode plate is contacted by wastewater.
  • the voltage and current applied to the cell can be varied.
  • step (c) of the first aspect and step (4) of the second aspect the voltage and amperage applied to the electrocoagulation cell and more particularly the electrodes thereof are calculated depending on the flow rate and conductivity of the wastewater.
  • flocculant is added in step (d) of the first aspect and step
  • (5) of the second aspect to increase the rate of solid separation.
  • greater than 80%, more preferably greater than 90% and most preferably greater than 95% of the fluoride species may be removed from the wastewater by the electrocoagulation process.
  • greater than 95%, and more preferably greater than 99% of the cyanide species may be removed from the wastewater by the electrocoagulation process.
  • Fig. 1 A schematic view of a fluoride species removal system comprising wastewater pretreatment, electrocoagulation and solid separation zones.
  • Fig. 2 A schematic view of a fluoride and cyanide species removal system.
  • water body is meant any body of water, such as creeks, springs, rivers, reservoirs, ponds and groundwater.
  • wastewater is meant any liquid or solution for treatment, for example, drinking water, a waste stream from industrial, mining or nuclear processes, or any contaminate water body.
  • Fig. 1 shows a schematic drawing of fluoride removal plant 1.
  • the wastewater is passed via conduit 4 through filter 5 which clarifies the wastewater by removing suspended solids in the form of micrometer and submicrometer (0.5-1.5 ⁇ m) particles.
  • the filter can be a sand filter, or a belt press or plate and frame type filter, and preferably at least two filters are necessary in case maintenance is required on a filter. It will be appreciated the filters can be modified to remove particles of any size.
  • the liquid overflow from filter 5 is transferred to tank 8 through conduit
  • Agitator 9 mixes the wastewater in tank 8 and a pH sensor 10 is located in tank 8, below the water level, to measure the pH of the wastewater on a continuous basis using an automated controller or microprocessor 11.
  • a signal proportional to the pH of the wastewater is transmitted via a conductor 12 to controller 11 that governs the operation of a control valve (not shown) that controls the flow of acid or alkali solution into tank 8.
  • a control valve not shown
  • the acid solution is added to mixing tank 8.
  • the acid solution is a mineral acid, such as sulphuric or hydrochloric acid. If the pH of the wastewater is less than 4.0, alkali solution is added to mixing tank 8.
  • the alkali solution is sodium hydroxide or potassium hydroxide or an alkaline earth species such as calcium hydroxide or lime.
  • This system maintains the pH within the desired range for electrocoagulation and the pH can be adjusted to fall within any desired range. For example, maintaining the pH between the limits of pH 4 and 8 may further enhance the electrocoagulation performance.
  • the outflow from mixing tank 8 then passes into the electrocoagulation treatment zone 20 through conduit 19 to undergo electrocoagulation.
  • a preferred embodiment of an electrocoagulation cell is described in WO 01/53568.
  • the electrocoagulation treatment zone 20, which incorporates tank 21 , electrocoagulation cell 22, coagulation tank 23 and conduits 24 and 25, treats the wastewater to induce fluoride species to precipitate, coalesce, coagulate or otherwise separate from the wastewater.
  • the wastewater is fed from tank 21 into electrocoagulation cell 22 through conduit 24.
  • An electric current is passed through the wastewater in electrocoagulation cell 22 via a plurality of flat plate metal electrodes to induce excitation of fluoride ions and simultaneously release electrode cations and water anions.
  • An electrochemical reaction occurs whereby fluoride and other contaminant species present in the wastewater complex out of solution and form a solid coagulant.
  • fluoride ions react with the aluminium electrode cations and precipitate as AIF 3 .
  • a critical current and voltage may be applied via the electrodes to the wastewater.
  • the current and voltage values are dependent on the following critical parameters: (i) number of electrodes used; (ii) total wetted surface area of electrodes in the cell; (iii) number of electrode connections to a DC power source; (iv) size of the gap between the electrodes; (v) pH of the wastewater; (vi) conductivity of the wastewater; and (vii) flow rate and cell residence time of the wastewater through the cell.
  • critical parameters (i) number of electrodes used; (ii) total wetted surface area of electrodes in the cell; (iii) number of electrode connections to a DC power source; (iv) size of the gap between the electrodes; (v) pH of the wastewater; (vi) conductivity of the wastewater; and (vii) flow rate and cell residence time of the wastewater through the cell.
  • the optimum parameters can be determined experimentally by a
  • a critical factor in determining the current and voltage values is the cell configuration, i.e. the number of electrodes in the cell, the gap between the electrodes and the number of electrodes that are connected to a DC power source. Electrodes are electrically connected to the DC power source via suitably rated cables and a bus bar arrangement, which can be bolted directly onto each unipolar electrode as required. Preferably, parameters such as the flow rate, total number of electrodes in the cell, the size of the gap between the electrodes and the number of electrodes that are connected to a DC power supply will be fixed.
  • the reaction plates extend across the width or length of electrolysis cell 22, and each side of the electrode is contacted by the water to allow maximum contact with the water flowing through the cell (total wetted surface area of cell). If a low flow rate is used (less than 10 L/min), a smaller cell design with a lower number of electrodes and less total power (voltage and current) is required. If a high flow rate is required (greater than 500 L/min), a large cell design with a greater number of electrodes and more total power (voltage and current) is necessary. Other important factors are the linear velocity of the solution through the cell and the cell residence time.
  • laminar flow is preferred based upon a cell residence time of 6.99 seconds and (a) a linear flow velocity through the cell, (b) orientated solution entry at the bottom of the cell, and (c) solution output vertically above the solution entry point and at the top of the cell.
  • the flow rate is fixed, another determining factor is the conductivity of the solution. For example, the higher the conductivity of the solution, fewer electrodes may be required to be electrically connected to a DC power source to give the optimum current for a determined voltage. If the total 5 number of electrodes and electrodes connected to a DC power source are fixed, the voltage value may decrease while the current value increases as the solution conductivity increases.
  • the method of determination of optimum voltage and current values is facilitated from knowledge of the chemical composition of the wastewater l o sample having regard to the criteria given above and use of a variac which is adjustable to increase or decrease voltage and current.
  • Optimum voltage and current values can be determined experimentally by visually observing the reaction point in the electrocoagulation process, i.e. the formation of coagulant in the form of micro-flocs in the discharged wastewater.
  • the is optimum electrocoagulation parameters may be calculated by a person skilled in the art using the methodology described in WO 03/086981 , incorporated herein by reference,
  • the power system controlling the electrocoagulation system may be automated to facilitate precise control and to provide flexibility in controlling 20 the electrocoagulation treatment zone 20.
  • the electrocoagulation treatment zone 20 and associated power system is designed to be compact and portable to facilitate transport to and use in industrial plants and mines.
  • the outflow from the electrocoagulation cell 22 passes to the coagulation tank 23 through an enclosed, sealed plastic conduit 25 that connects the discharge spout of the cell to the coagulation tank or mixing tank 23.
  • the sealed conduit 25 ensures that water vapour or aerosols do not enter the atmosphere and are drawn into mixing tank 23 by a partial vacuum induced by the flowing stream of water within the conduit 25.
  • the wastewater may be transferred to a settling tank 27 through conduit 26. Flocculating agents may be added to settling tank 27 to accelerate gravity separation of solid particles contained in the discharged wastewater and also to neutralise the anionic or cationic charge of the wastewater.
  • Suitable flocculants can be found in the GE Betz catalogue (www.qebetx.com) and include cationic emulsion polymers and anionic emulsion polymers, such as Novus CE emulsion polymers, for example Novus Polymer 2681 , and AE 1123.
  • the wastewater may remain in settling tank 27 for one hour.
  • the wastewater may then be passed to a sludge thickener tank 28 through conduit 29 in which particle growth and rapid sedimentation and gravity separation of solid particles occurs.
  • the underflow from the sludge thickener tank 28 may be de-watered or dried prior to disposal by passage through conduits 28A and 30 to a suitable disposal location.
  • the outflow from the sludge thickener tank 28 may be transferred through conduits 28A and 31 to a holding tank (not shown) from which the wastewater may again be treated by passage to the electrocoagulation treatment zone 20.
  • a holding tank not shown
  • any second pass of the wastewater through the electrocoagulant treatment zone 20 may not be required, subject to the efficiency of fluoride removal through the first pass treatment cycle.
  • An alternative to discharging the treated wastewater would be to reuse, or recycle the treated water. This is particularly advantageous for industrial applications where water usage is high. Purified water may also be discharged back into the contaminated water body source.
  • the system can be modified to remove both fluoride and cyanide species from wastewater, for example to treat wastewater produced by the aluminium industry.
  • FIG. 2 shows a schematic drawing of a fluoride and cyanide species removal plant 2.
  • the wastewater is passed through fluoride removal plant 1 , as described above, through conduit 32 into holding tank 3 which comprises an agitator or impeller (not shown) to maintain any suspended solids in suspension.
  • the wastewater is passed via conduit 4 into filter 5 to remove suspended solids. It is very important that the maximum amount!
  • Filter 5 can be modified to remove solid particles of any size, As described above, the liquid overflow from filter 5 is transferred to tank 8 where the pH of the wastewater is measured. If the pH of the wastewater is greater than 8.5, an acid solution is added to mixing tank 8. If the pH of the wastewater is less than 6.0, alkali solution is added to mixing tank 8. Preferably, the pH is adjusted so it falls within the range of pH 7.0- 8.2. The wastewater is transferred from tank 8 to tank 16 via conduit 15. Agitator 9 mixes the wastewater in tank 16 and a conductivity detector 17 is located in tank 16, below the water level, to measure the conductivity of the wastewater on a continuous basis.
  • the conductivity of the wastewater is controlled using an automated controller or microprocessor 18.
  • a signal proportional to the conductivity of the wastewater solution is transmitted via conductor 18A to the automated controller or microprocessor 18 that governs the operation of a control valve (not shown) that controls the flow of an ionic solution into mixing tank 16.
  • the ionic solution is an ionic salt of any kind such as a soluble alkali or alkaline earth salt inclusive of NaCI, KCI or CaNO 3 . If the conductivity of the wastewater is greater than 5,000, more suitably 4,500, and more preferably 3,800 ⁇ S/cm, flow of the ionic solution into mixing tank 16 may be restricted.
  • ionic solution flow to mixing tank 16 may be increased. This system maintains the conductivity within the desired range for electrocoagulation of a cyanide species.
  • the outflow from tank 16 then passes into electrocoagulation zone 20 through conduit 19, and electrocoagulation is carried out as described above.
  • a critical current and voltage may be applied via the stainless steel electrodes to the wastewater. The current and voltage values are dependent on the critical parameters described above.
  • Electrodes 1 , 8 and 15 are anodes and electrodes 4, 11 and 18 are cathodes.
  • Other electrode maps may be determined experimentally.
  • Flocculating agents may be added to the treated wastewater in settling tank 27 to accelerate gravity separation of solid particles. Suitable flocculants include AE1123 and Klaraid PC1190. As described above the treated wastewater can be transferred back to holding tank 3 for a second pass through electrocoagulation zone 20.
  • Modifications may be made to the fluoride and cyanide species removal process. Any of the pre-treatment or post-treatment steps may be omitted subject to the nature or composition of the wastewater. Removal of fluoride ions from the wastewater prior to passing the wastewater through cyanide species removal plant 2 increases the efficiency and effectiveness of cyanide species removal by plant 2. This may be due to the fluoride species removal process reducing the concentration of a competitive anion or a reaction quenching anion. The fluoride species removal process also removes suspended solids and particulate matter which potentially leach cyanide species into the wastewater. Preferably, plantsl and 2 and associated power system are designed to be compact and portable to facilitate transport to and use in industrial plants or at contaminated water bodies.
  • Example 1 The wastewater was obtained from an aluminium plant.
  • the raw wastewater contained 57 mg/litre of fluoride containing compounds and had a conductivity of 450 ⁇ S/cm and pH 6.3.
  • the following electrocoagulation parameters were used for a fixed flow rate of 1 litre/minute:
  • the electrocoagulation cell comprises 8 aluminium electrodes with electrical connections to a DC power supply made to 4 electrodes (2 anodes and 2 cathodes).
  • Test l The electrocoagulation cell comprises 8 aluminium electrodes with electrical connections to a DC power supply made to 4 electrodes (2 anodes and 2 cathodes).
  • Second pass treatment of the treated wastewater of Test 2 was carried out. 55 volts and 4.4 amps were applied to the cell.
  • Example 2 The wastewater was obtained from an aluminium plant.
  • the raw wastewater contained 51.4 mg/litre of fluoride containing compounds and had a conductivity of 920 ⁇ S/cm and pH 6.1.
  • the following electrocoagulation parameters were used for a fixed flow rate of 1 litre/minute:
  • the electrocoagulation cell comprises 8 aluminium electrodes with electrical connections to a DC power supply made to 4 electrodes (2 anodes and 2 cathodes).
  • Test 2 59 volts and 10.4 amps were applied to the cell.
  • the conductivity of the raw wastewater was raised to 12,000 ⁇ S/cm prior to electrocoagulation.
  • Test 3 58 volts and 10.2 amps were applied to the cell.
  • the conductivity of the raw wastewater was raised to 12,000 ⁇ S/cm and the pH was adjusted to 5.0 prior to electrocoagulation.
  • Example 3 The wastewater was obtained from an aluminium plant. The raw wastewater contained 257 mg/litre of fluoride containing compounds and 4.0 mg/L cyanide. The raw wastewater had a conductivity of 2050 ⁇ S/cm and pH
  • the electrocoagulation cell comprises 8 aluminium electrodes with electrical connections to a DC power supply made to 4 electrodes (2 anodes and 2 cathodes).
  • Test l The pH was adjusted to pH 5.5, and the conductivity was adjusted to 3650. 87 volts and 280 amps were applied to the cell. No pre-treatment of the wastewater was carried out. Results 49.1 mg/L of fluoride was measured in the treated water.
  • the wastewater was then passed through a second electrocoagulation cell to remove cyanide from the wastewater.
  • the electrocoagulation cell comprises 8 stainless steel electrodes with electrical connections to a DC power supply made to 4 electrodes (2 anodes and 2 cathodes). 87 volts and 280 amps were applied to the cell.
  • the wastewater was allowed to settle for at least 2 hours and then filtered prior to electrocoagulation treatment. Results 0.126 mg/L of cyanide and 50 mg/L of fluoride was measured in the treated water.
  • the advantages of this invention are as follows: (i) the wastewater is treated on a continuous flow treatment basis, enabling the rapid treatment of large volumes of water and can treat effectively 1-1000 L/min/m 2 ; (ii) electrocoagulation destabilizes and therefore removes suspended, emulsified or dissolved contaminants in an aqueous medium;
  • the process removes > 80% fluoride species from the wastewater in a single pass and greater than 90% in a double pass through the system; (iv) the process results in a low volume, aqueous stable sludge that is readily separated from a liquid stream for subsequent disposal. Typically the process generates a much lower amount of sludge compared to conventional methods, such as lime treatment; (v) a minimum amount of chemical are used in the process;
  • the process can remove both fluoride and cyanide species from wastewater; (vii) the process can perform effectively the simultaneous treatment of multiple contaminants, such as oils and greases;

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  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)

Abstract

L'invention concerne un procédé permettant d'éliminer des espèces de fluorure libres et/ou complexes d'eaux usées et comprenant les étapes consistant : à éliminer des solides en suspension des eaux usées; à adapter le pH des eaux usées de manière qu'il tombe dans la gamme allant de 4 à 8; à faire passer l'eau dans une chambre de réaction d'électrocoagulation comprenant une pluralité de plaques de réaction ou d'électrodes disposées dans ladite chambre de réaction et espacées les unes des autres, les plaques étant fabriquées en aluminium et au moins deux de ces plaques étant connectées électriquement à une alimentation; et à séparer des solides des eaux usées. L'invention concerne également un procédé permettant d'éliminer des espèces de fluorure et de cyanure libres et/ou complexes des eaux usées et comprenant les étapes consistant: à éliminer des espèces de fluorure des eaux usées; et à faire passer les eaux usées dans une chambre de réaction d'électrocoagulation, aux fins d'élimination des espèces de cyanure.
PCT/AU2005/000293 2004-03-01 2005-03-01 Procede d'elimination d'especes de fluorure WO2005082788A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2004901018A AU2004901018A0 (en) 2004-03-01 Fluoride species removal process
AU2004901018 2004-03-01

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GB2444114A (en) * 2006-11-23 2008-05-28 Ramsey Yousif Haddad An electrolytic process for the treatment of effluent
KR101270310B1 (ko) * 2011-04-26 2013-05-31 조선대학교산학협력단 일체형 워터젯 글라이딩 아크 플라즈마 스크러버 장치
CN104261624A (zh) * 2014-09-29 2015-01-07 长春黄金研究院 一种黄金氰化企业含氰废水处理方法
CN105776683A (zh) * 2016-05-11 2016-07-20 常熟林润氟硅材料有限公司 一种高频脉冲电化学废水处理系统
KR101675791B1 (ko) * 2016-05-27 2016-11-15 (주)성현하이텍 알칼리 환원수 생성시스템
CN114956479A (zh) * 2022-06-20 2022-08-30 北京耐特尔环境工程技术有限公司 一种针对疏干水深度除氟脱氮的处理方法
CN115872569A (zh) * 2022-12-30 2023-03-31 西昌学院 提高氟污染物去除效能的电化学耦合膜过滤方法及系统

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU1116019A1 (ru) * 1982-04-14 1984-09-30 Молдавский Государственный Институт Проектирования Гражданского Сельского Строительства Способ обесфторивани артезианских вод
US5611907A (en) * 1994-04-18 1997-03-18 Global Water Industries, Inc. Electrolytic treatment device and method for using same
JP2001113284A (ja) * 1999-10-15 2001-04-24 Japan Organo Co Ltd 排水処理方法及び装置
WO2002026643A1 (fr) * 2000-09-26 2002-04-04 Microbar, Inc. Elimination du fluorure des eaux usees au moyen d'une electrode d'entree sensible au fluorure
WO2003086981A1 (fr) * 2002-04-08 2003-10-23 Aquenox Pty Ltd Procede d'installation d'un appareil d'elimination de contaminants

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU1116019A1 (ru) * 1982-04-14 1984-09-30 Молдавский Государственный Институт Проектирования Гражданского Сельского Строительства Способ обесфторивани артезианских вод
US5611907A (en) * 1994-04-18 1997-03-18 Global Water Industries, Inc. Electrolytic treatment device and method for using same
JP2001113284A (ja) * 1999-10-15 2001-04-24 Japan Organo Co Ltd 排水処理方法及び装置
WO2002026643A1 (fr) * 2000-09-26 2002-04-04 Microbar, Inc. Elimination du fluorure des eaux usees au moyen d'une electrode d'entree sensible au fluorure
WO2003086981A1 (fr) * 2002-04-08 2003-10-23 Aquenox Pty Ltd Procede d'installation d'un appareil d'elimination de contaminants

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 198516, Derwent World Patents Index; AN 1985-097669 *
DATABASE WPI Week 200201, Derwent World Patents Index; AN 2002-001924 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2444114A (en) * 2006-11-23 2008-05-28 Ramsey Yousif Haddad An electrolytic process for the treatment of effluent
GB2444114B (en) * 2006-11-23 2009-03-11 Ramsey Yousif Haddad Ridding water of contaminants
KR101270310B1 (ko) * 2011-04-26 2013-05-31 조선대학교산학협력단 일체형 워터젯 글라이딩 아크 플라즈마 스크러버 장치
CN104261624A (zh) * 2014-09-29 2015-01-07 长春黄金研究院 一种黄金氰化企业含氰废水处理方法
CN105776683A (zh) * 2016-05-11 2016-07-20 常熟林润氟硅材料有限公司 一种高频脉冲电化学废水处理系统
KR101675791B1 (ko) * 2016-05-27 2016-11-15 (주)성현하이텍 알칼리 환원수 생성시스템
CN114956479A (zh) * 2022-06-20 2022-08-30 北京耐特尔环境工程技术有限公司 一种针对疏干水深度除氟脱氮的处理方法
CN115872569A (zh) * 2022-12-30 2023-03-31 西昌学院 提高氟污染物去除效能的电化学耦合膜过滤方法及系统

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