Water treatment device and water treatment method

Abstract

To provide a water treatment apparatus and a water treatment method capable of maintaining efficient fluorine removal ability over a long term.SOLUTION: A water treatment apparatus 100 includes an outer cylinder 1 arranged vertically and an inner cylinder 2 arranged vertically inside the outer cylinder 1. It has the inner cylinder 2 that defines an annular space T between the outer cylinder 1 and the inner cylinder 2 and a cylindrical space C inside the inner cylinder 2, a screw 5 that conveys the granular treatment material in the cylindrical space C upward and overflows from the upper end of the inner cylinder 2 into the annular space T, an introduction port 11 for introducing the granular treatment material that has descended into the cylindrical space C, and a water supply port 12 that is connected to the cylindrical space C from below and supplies water required for treatment into the cylindrical space C.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a water treatment device and a water treatment method. [Background technology]

[0002] Patent Document 1 describes a solid-liquid contact wastewater treatment device having a vertical fluidized bed, in which a vertical screw conveyor is provided in the center of the fluidized bed and a draft tube is provided concentrically around the screw conveyor, with the inside of the draft tube being an upward moving bed and the outside being a downward moving bed. In this wastewater treatment device, activated carbon, arethracite, zeolite, and plastic pellets are listed as carriers used in the fluidized bed, and ammonia and COD are listed as substances to be treated contained in the wastewater.

[0003] Patent Document 2 describes a water purification device comprising a water treatment tank, an inner cylinder formed inside the water treatment tank, a water purification section formed between the inner cylinder and the outer cylinder of the water treatment tank, a separation material supply section arranged above the water purification section, an upper raw water supply section arranged above the water purification section and / or a lower raw water supply section arranged on the lower side of the outer cylinder, a separating material and raw water inlet formed on the bottom side of the inner cylinder and communicating with the water purification section, a separating material discharge section arranged at a position higher than the liquid level of the raw water in the inner cylinder and discharging a separating material made of a metal or alloy capable of adsorbing metal ions contained in the raw water from the upper side to the water purification section, a screw rotatably arranged on the central axis of the inner cylinder, a drive section for rotating the screw, and a purified water discharge section arranged on the outer cylinder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 53-59252 [Patent Document 2] Patent No. 6023159 Summary of the Invention [Problem to be solved by the invention]

[0005] Because fluorine-containing compounds such as PFOS (perfluorooctane sulfonic acid) and PFOA (perfluorooctanoic acid) are chemically stable, high-temperature thermal decomposition is a practical method for treating them. While this generates fluorine gas in the exhaust, contacting the exhaust with water removes the fluorine gas, thereby reducing its release into the environment.

[0006] As a result, fluorine-containing water requiring treatment is generated. Since the fluorine in the water requiring treatment is mostly contained in the form of hydrofluoric acid, it is necessary to use an appropriate treatment agent, for example, a metal-containing treatment agent. Material By contacting and reacting with fluorine, the fluorine is fixed as a metal fluoride, allowing it to be safely disposed of.

[0007] In the treatment of removing fluorine from such fluorine-containing water requiring treatment, there is no known water treatment apparatus or method that can efficiently maintain its fluorine removal capacity for a long period of time.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a water treatment apparatus and a water treatment method that can efficiently maintain the ability to remove fluorine for a long period of time. [Means for solving the problem]

[0009] The invention disclosed in this application to solve the above problems has various aspects, and representative aspects thereof are outlined below.

[0010] (1) A vertically disposed outer cylinder, an inner cylinder disposed vertically inside the outer cylinder, and the inner cylinder defining an annular space between the outer cylinder and the inner cylinder and a cylindrical space inside the inner cylinder, a screw conveying the granular processing material in the cylindrical space upward and causing it to overflow from the upper end of the inner cylinder into the annular space, and a screw conveying the granular processing material descending inside the annular space. Material and a water supply port connected to the cylindrical space from below and supplying water to be treated into the cylindrical space.

[0011] In (2), the granular processing in at least the cylindrical space Material A water treatment device equipped with a vibrator that applies vibration to the water.

[0012] (3) In the water treatment device according to (1) or (2), the surface of the screw is provided with an anti-slip shape.

[0013] (4) The water treatment device according to any one of (1) to (3), wherein at least the surface of the screw is made of a material capable of treating the water to be treated.

[0014] (5) The granular treatment device is placed in the cylindrical space of the water treatment device of (4). Material The water to be treated is supplied from the water supply port, the screw is rotated, and the granular treatment Material and a water treatment method for removing a substance to be treated from the water to be treated by conveying the water to be treated upward in the cylindrical space, wherein the material of the screw is a granular treatment material. Material The water treatment method according to any one of the preceding claims, further comprising a metal element that reacts and fixes the substance to be treated.

[0015] (6) In (5), the water treatment method is characterized in that the metal element is iron or magnesium.

[0016] (7) The granular treatment device is provided in the cylindrical space of the water treatment device according to any one of (1) to (4). Material The water to be treated is supplied from the water supply port, the screw is rotated, and the granular treatment Materialand a water treatment method for conveying the water to be treated upward in the cylindrical space and removing substances to be treated from the water to be treated, the method comprising: surface and the granular processing Material The dry friction coefficient of the water is 0.1 or more.

[0017] (8) The water treatment method according to any one of (5) to (7), wherein at least one of surface active components and oil components is removed from the water to be treated, and the water is then supplied to the water treatment device.

[0018] (9) In (8), the removal of at least one of the surface active components and oil components is carried out by passing the water to be treated through an adsorption tank filled with a filter material made of at least one of activated carbon and ion exchange resin.

[0019] (10) In (8), the removal of at least one of the surface active component and the oil component is carried out by adsorbing the water to be treated. Material and separating the water to be treated from the adsorbent using a filter. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram showing a configuration of a water treatment device according to a preferred embodiment of the present invention. [Figure 2] 10A and 10B are diagrams illustrating examples of anti-slip shapes. [Figure 3] FIG. 10 is a diagram illustrating an example of preprocessing. [Figure 4] FIG. 10 is a diagram illustrating another example of preprocessing. DETAILED DESCRIPTION OF THE INVENTION

[0021] FIG. 1 is a diagram showing the configuration of a water treatment device 100 according to a preferred embodiment of the present invention.

[0022] The water treatment device 100 treats water to be treated by granular treatment. Material By mixing with and fluidizing, granular processing Material This device continuously treats water requiring treatment by contacting the surface of the container with the target substance, particularly fluorine, in the water to be treated, and then discharging the treated clean water from the container.

[0023] The water treatment device 100 has a double-cylinder structure in which a cylindrical outer cylinder 1 constituting the container is arranged vertically and an inner cylinder 2 arranged vertically inside the outer cylinder 1. The inner cylinder 2 defines and divides the internal space of the outer cylinder 1 into an annular space T between the outer cylinder 1 and the inner cylinder 2 and a cylindrical space C inside the inner cylinder 2.

[0024] The bottom of the outer cylinder 1 is closed by a bottom plate 3. The lower end of the inner cylinder 2 protrudes downward from the lower end of the outer cylinder 1, and the lower end of the inner cylinder 2 and the lower end of the outer cylinder 1 are connected by an inclined portion 4 of the bottom plate 3, so that the bottom plate 3 has a bowl-like shape that slopes from the annular space T toward the cylindrical space C.

[0025] A screw 5 is provided vertically within the cylindrical space C, and is rotated by a motor 7 attached to a lid 6 provided on the top of the outer cylinder 1. The screw 5 has a structure in which a spiral blade 9 is provided around a shaft 8, and the rotation of the motor 7 transports the fluid within the cylindrical space C upward. The end of the shaft 8 opposite the motor 7 is supported by a retainer 10 on the bottom plate 3 in a liquid-tight and rotatable manner.

[0026] The water treatment device 100 contains water to be treated and granular treatment water in this container. Material The motor 7 is driven to rotate the screw 5, causing a fluid flow as shown by the arrows in Figure 1, and the water to be treated and the granular treatment water are separated. Material By mixing the granular treatment material with the granular treatment material, the target substance in the water to be treated is brought into contact with the surface of the granular treatment material and fixed. Material The granular treatment water is mixed and stirred with the water to be treated and transported upward in the cylindrical space C, and overflows from the top end of the inner cylinder 2 into the annular space T. MaterialThe water falls due to gravity, flows down the inclined portion 4 of the bottom plate 3, is introduced into the cylindrical space C through an inlet 11 provided on the lower side surface of the inner cylinder 2, and circulates within the water treatment device.

[0027] The water to be treated is directly supplied into the inner cylinder 2 from a water supply port 12 connected to the bottom of the cylindrical space C. Material The treated water, from which the target substances have been removed by sufficient contact with the outer cylinder 1, is discharged as treated water from the water outlet 13 provided on the upper side surface of the outer cylinder 1. Here, the height direction of the water outlet 13 is arranged so that it is higher than the upper end of the inner cylinder 2. Therefore, during operation of the water treatment device 100, the granular treated water conveyed through the inner cylinder 2 and the cylindrical space C within the inner cylinder 2 is discharged. Material is submerged without rising above the water surface.

[0028] As described above, water treatment device 100 is designed to be particularly suited to the removal of fluorine from water to be treated. However, the removal of fluorine is not necessarily limited thereto, and water treatment device 100 can also be used to remove other water contaminants, and can also be operated to remove other water contaminants in addition to fluorine. However, the following description will be given of the device being used specifically to remove fluorine from water.

[0029] Fluorine in water is treated to produce solid fluorine compounds Material The treatment agent can be fixed by contacting it with calcium hydroxide and reacting it with the metal, and then removed from the water to be treated. Various materials, including various metals and calcium compounds such as quicklime, can be used as such treatment agents, and can be used in the water treatment device 100 by making them into fluid granules.

[0030] At this time, there are some points to keep in mind when trying to carry out water treatment efficiently over a long period of time. One of them is the granular treatment by the screw 5. Material The object is to smoothly transport the material upward in the cylindrical space C.

[0031] The surface of the granular treatment material reacts with the fluorine in the water to be treated, forming a stable solid film of metal fluorides, etc. Therefore, if the entire surface reacts with fluorine and is covered with a solid film, the granular treatment material loses its ability to adsorb fluorine. Material The particles are constantly stirred and rub against each other, scraping away the solid film and constantly exposing a new surface, thereby maintaining processing capacity for a long period of time.

[0032] However, granular processing Material If the material slides down the spiral blade of the screw 5 and is not conveyed upward sufficiently, the granular material may be Material This will result in insufficient stirring of the wastewater and insufficient removal of the solid film, leading to a decrease in treatment capacity. Material The mixing of the treated water and the treated water tends to be insufficient, and insufficient treated water tends to be discharged from the outlet 13.

[0033] Therefore, the spiral blade 9 of the screw 5 is Material It is necessary to support the material without it slipping off and transport it upwards reliably. Material It is necessary that the surface of the spiral blade 9 is not slippery. Material The dry friction coefficient between the surface of the spiral blade 9 and the surface of the spiral blade 9 is set to 0.1 or more, more preferably 0.15 or more. Material 1 shows the relationship between the material of the spiral blade 9 and the dry friction coefficient when used as

[0034] [Table 1]

[0035] In addition, a non-slip shape 14 may be provided on the surface of the spiral blade 9. FIG. 2 is a diagram showing an example of the non-slip shape 14, and is a diagram showing the surface of the spiral blade 9 when the screw 5 is viewed from the axial direction. The non-slip shape 14 shown in the figure is a radial ridge-like protrusion centered on the shaft 8, and is formed by the granular treatment on the spiral blade 9. MaterialThe material is caught by the anti-slip shapes 14 and conveyed upward without slipping off. The shapes of the anti-slip shapes 14 are not limited to those shown individually, and may be knurled shapes or any uneven shapes formed by shot peening.

[0036] Furthermore, granular processing Material When the material is conveyed upward by the screw 5, the granular processing Material Not only with each other, but also with granular processing Material Wear also occurs between the helical blade 9 and the suction cup 102. Therefore, the newly formed surface of the helical blade 9 is always exposed while the water treatment device 100 is in operation.

[0037] Therefore, by forming the helical blade 9 of the screw 5 itself from a material capable of treating the water requiring treatment, the contact area between the water requiring treatment and the treatment material can be further increased, thereby improving the treatment capacity. For example, if the substance to be treated is fluorine, a material that reacts with fluorine and has sufficient strength and durability as a structural material should be selected. Specific examples include steel, iron-containing alloys, and magnesium alloys, as listed in Table 1 above.

[0038] Furthermore, granular processing Material The material of the spiral blade 9 may be selected taking into consideration the material of the metal. Generally, the dry friction coefficient between metal materials is large between the same metal or alloys containing the same metal elements. Material If a magnesium-based material is used, the spiral blade 9 is made of a magnesium alloy, and the granular treatment Material If the spiral blade 9 is made of a material mainly made of iron, it is preferable to use an iron-containing material such as steel for the spiral blade 9 .

[0039] The second point to keep in mind when trying to carry out water treatment efficiently over the long term is the granular treatment. Material This is a measure to prevent wear caused by the flow of the granules in the container. MaterialThe upward transport capacity within the cylindrical space C is important, and if fluorine is the substance to be treated, the granular treatment Material It is thought that hard materials such as magnesium-based materials and iron-based materials will often be selected as the material for the bearing.

[0040] 1, the water supply port 12 is connected from the bottom of the cylindrical space C for this reason. Material When the water treatment device 100 is placed in the flow path indicated by the arrow in FIG. 1, the hard granular treatment material is always present during operation of the water treatment device 100. Material This will cause the water supply pipe to collide with the object and cause severe damage to it.

[0041] However, if the water supply port 12 is provided on the side of the outer cylinder 1 or on the inclined portion 4 of the bottom plate 3, some of the supplied water to be treated will escape from the annular space T to the top of the container rather than into the cylindrical space C inside the inner cylinder 2, and will be discharged from the water outlet 13, which may reduce the treatment capacity.

[0042] Therefore, the water supply port 12 is connected to the lower side of the cylindrical space C, and the water to be treated can be supplied directly to the cylindrical space C without crossing the annular space T or the space above the inclined portion 4. A filter such as a metal mesh is placed at the outlet of the water supply port 12 to the cylindrical space C, and the water to be treated is filtered. Material It is also possible to prevent the entry of the wear debris into the water supply pipe.

[0043] Granular Processing Material The surface of the granular treatment unit 100 wears and becomes smaller with the long-term operation of the water treatment device 100. Therefore, it is necessary to periodically or as needed insert new granular treatment unit 100 through a maintenance port 15, which is an opening provided in the lid 6. Material A separate lid may be provided for the maintenance port.

[0044] Also, granular processing MaterialWear debris, such as metal fluorides with fixed fluorine, generated from the spiral blades 9 settles on the bottom plate 4, and can be discharged periodically or as needed from a discharge port 16 provided in the bottom plate 4. The discharge port 16 may be provided with a metal mesh or the like (not shown), and the granular treatment Material Alternatively, the mesh size of the metal mesh may be set to allow the passage of wear debris and granular processing particles whose particle size has become smaller than a predetermined size due to wear. Material It may be set so that the

[0045] Furthermore, the water treatment device 100 is configured to treat granular matter in the cylindrical space C. Material The inner cylinder 2 may be provided with a vibrator 17 for vibrating the granular processing material. As an example, the vibrator 17 is an ultrasonic vibrator provided on the upper side surface of the inner cylinder 2 as shown in FIG. 1. The vibration generated by the vibrator 17 is transmitted to the granular processing material in the cylindrical space C. Material transmitted to the granular processing Material The fluidity of granular processing is improved. Material As the particles are compacted together, they come into closer contact with each other, increasing the effect of rubbing against each other, further improving the granular processing. Material This allows the surface to remain fresh, further improving processing capacity.

[0046] The arrangement position, number, shape, and vibration frequency of the vibrators 17 are optional. Material Depending on the granular processing Material A configuration that efficiently applies vibration to the object may be selected as appropriate.

[0047] As described above, in the water treatment device 100 according to this embodiment, the screw 5 Material By transporting the water upwards and stirring and mixing it, high water treatment capacity can be maintained for a long period of time. Material It is important that the surfaces are worn away by rubbing against each other, and that a new surface is constantly formed on the surface.

[0048] From this viewpoint, the water to be treated is treated with granular treatment before being supplied to the water treatment device 100. Material It is effective to remove factors that inhibit the action of the particles rubbing against each other. In other words, if the water to be treated contains surfactants or oils, these will act to prevent the particles from rubbing against each other. Material Friction between particles and granular processing Material Friction between the spiral blade 9 and the water treatment device 100 may decrease, which may result in a decrease in the treatment capacity of the water treatment device 100.

[0049] An example of such pretreatment is shown in Figure 3. As shown in the figure, before the water to be treated is supplied to the water treatment device 100, the water is passed through an adsorption tank 200 filled with a filter medium such as activated carbon or ion exchange resin to remove surface active components and oils, thereby enabling the water treatment device 100 to perform treatment more effectively.

[0050] Fig. 4 shows another example of such pretreatment. As shown in the figure, activated carbon, zeolite, etc. are added to the water to be treated. Material The mixture is mixed and stirred, and the water to be treated is absorbed by the filter. Material By separating the adsorbed water and removing the surfactants and oils from the treated water, the treated water is supplied to the water treatment device 100, thereby enabling effective treatment in the water treatment device 100. Material The water to be treated is mixed with the mixture 301 and stirred by a submerged mixer 302, and the surface active components and oils in the water to be treated are removed. After removal, the water to be treated is absorbed by a filter 303. Material The water is separated from the filter 301 and supplied to the water treatment device 100. In the figure, a mesh screen is used as the filter 303, but the filter 303 absorbs the water to be treated. Material Any device that can separate 301 may be used, including mechanical separation, such as a centrifugal separator using a cyclone or the like. [Explanation of symbols]

[0051] 1 outer cylinder, 2 inner cylinder, 3 bottom plate, 4 inclined portion, 5 screw, 6 lid, 7 motor, 8 shaft, 9 spiral blade, 10 retainer, 11 inlet, 12 water supply port, 13 water outlet, 14 non-slip shape, 15 maintenance port, 16 outlet, 17 vibrator, 100 water treatment device, 200 treatment tank, 300 treatment water tank, 301 adsorption Material , 302 submersible agitator, 303 filter, C cylindrical space, T annular space.

Claims

1. An outer cylinder arranged vertically; an inner cylinder disposed vertically within the outer cylinder, the inner cylinder defining an annular space between the outer cylinder and the inner cylinder and a cylindrical space within the inner cylinder; a screw that conveys the granular material in the cylindrical space upward and overflows it from the upper end of the inner cylinder into the annular space; an inlet for introducing the granular treatment material that has descended within the annular space into the cylindrical space; a water supply port connected to the cylindrical space from below and supplying water to be treated into the cylindrical space; A water treatment device comprising:

2. The water treatment device according to claim 1, further comprising a vibrator for vibrating at least the granular treatment material in the cylindrical space.

3. The water treatment device according to claim 1 or 2, wherein a non-slip shape is provided on the surface of the screw.

4. The water treatment device according to any one of claims 1 to 3, wherein at least the surface of the screw is made of a material capable of treating the water requiring treatment.

5. The granular treatment material is filled in the cylindrical space of the water treatment device according to claim 4, The water to be treated is supplied through the water supply port, A water treatment method comprising: rotating the screw to transport the granular treatment material and the water to be treated upward in the cylindrical space; and removing a treatment target substance from the water to be treated, A water treatment method, wherein the material of the screw contains a metal element that is common to the granular treatment material and reacts and fixes the substance to be treated.

6. The water treatment method according to claim 5 , wherein the metal element is iron or magnesium.

7. The granular treatment material is filled in the cylindrical space of the water treatment device according to any one of claims 1 to 4, The water to be treated is supplied through the water supply port, A water treatment method comprising: rotating the screw to transport the granular treatment material and the water to be treated upward in the cylindrical space; and removing a treatment target substance from the water to be treated, A water treatment method, wherein the dry friction coefficient between the surface of the screw and the granular treatment material is 0.1 or more.

8. The water treatment method according to any one of claims 5 to 7, wherein at least one of surfactant components and oil components is removed from the water to be treated, and the water is then supplied to the water treatment device.

9. The water treatment method according to claim 8, wherein the removal of at least one of the surface active components and oil components is carried out by passing the water to be treated through an adsorption tank filled with a filter medium made of at least one of activated carbon and ion exchange resin.

10. The water treatment method according to claim 8, wherein the removal of at least one of the surface active components and oil components is carried out by mixing and stirring the water to be treated with an adsorbent, and separating the water to be treated from the adsorbent using a filter.

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