JP2012020219A - Wastewater treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wastewater treatment apparatus which efficiently irradiates light on a photocatalyst to improve the decomposition performance of organic substances in wastewater.SOLUTION: A first wastewater treatment apparatus 10A is a wastewater treatment apparatus for treating organic substances in wastewater 11 and has a wastewater treatment tank 12 for storing the wastewater 11, a light source 13, a photocatalyst covered light leaking and introducing body 17 installed in the wastewater treatment tank 12 and formed by covering the surface of a light leaking and introducing body 15 for leaking light 14 irradiated from the light source 13 while introducing the light 14 with a photocatalyst layer 16 containing a photocatalyst, and an optical fiber 18 for introducing the light 14, irradiated from the light source 13, to the light leaking and introducing body 15.

Description

  The present invention relates to a wastewater treatment apparatus for treating wastewater containing organic matter.

There is a wastewater treatment method using a photocatalyst as a method of decomposing organic matter in wastewater. For example, a method has been proposed in which an organic substance or the like is adsorbed and removed using activated carbon or the like carrying a photocatalyst as an adsorbent, and the activated carbon carrying the photocatalyst is irradiated with ultraviolet rays or visible light to treat the organic substance ( For example, see Patent Document 1). In addition to using photocatalyst as a method for treating organic matter in wastewater, ozone (O ₃ ) is added to wastewater containing organic matter and irradiated with ultraviolet light to decompose and treat organic matter in wastewater. Has been proposed (see, for example, Patent Document 2). These treatment methods are conventionally used as an effective waste water treatment technique for waste water treatment facilities as a supplementary device for the activated sludge method and the physicochemical treatment method.

  When the organic matter in the wastewater is decomposed using the photocatalyst, in addition to using the photocatalyst supported on activated carbon, for example, a method of using the photocatalyst supported on zeolite or the like as an adsorbent can also be used. In addition, a glass container with high light transmittance, a method of using a composition in which a photocatalyst is supported on plastic or the like and molded into a tube structure, a surface of a transparent cylindrical body having light transparency molded with a glass container or plastic, etc. And a method of coating the back surface with a photocatalyst (see, for example, Patent Documents 3 and 4). Furthermore, a plurality of hollow tubes having a plurality of fine holes on the tube wall are bundled in a cylindrical shape and arranged in a container, and each hollow tube is filled with a photocatalyst, or a photocatalyst is attached to the inner wall and the outer wall of the hollow tube. There is a method of providing a reflecting mirror around a light source and irradiating a plurality of hollow tubes with light from the light source (see, for example, Patent Document 5). By using a photocatalyst by the above method, organic substances in the wastewater can be decomposed into carbon dioxide and water.

JP-A-11-10136 Japanese Patent Laid-Open No. 11-104618 JP 2000-354762 A JP 2000-93952 A Japanese Patent Laid-Open No. 11-290656

  However, even if light is externally applied to a container containing a glass container or the like coated with a photocatalyst, the inner glass container or the like is blocked by a glass container or the like disposed on the outside, or is coated with a photocatalyst If there are multiple glass containers, the back container is shaded so that light is blocked, or if the water in the container is turbid, light is scattered and light is blocked, so all There is a problem that a glass container or the like coated with a photocatalyst cannot be sufficiently irradiated with light. Therefore, the catalytic function of the photocatalyst coated on the glass container or the like provided in the container is not sufficiently exhibited, so that organic substances in the wastewater are not sufficiently decomposed and removed, and a sufficient wastewater treatment effect cannot be obtained.

  Therefore, there is a demand for a wastewater treatment apparatus that can efficiently irradiate light onto a photocatalyst and efficiently decompose and remove organic substances in the wastewater.

  In view of the above problems, an object of the present invention is to provide a wastewater treatment apparatus that efficiently irradiates light to a photocatalyst and improves the decomposition performance of organic matter in wastewater.

  In order to solve the above-described problems and achieve the object, the present inventors have intensively studied a wastewater treatment apparatus. As a result, by irradiating light from the inside to the outside of the photocatalyst layer through the leaking light guide, it is possible to irradiate the photocatalyst layer efficiently without waste. It was found that it can be decomposed and removed well, and the decomposition performance of organic matter in waste water can be improved. The present invention has been completed based on such findings.

  1st invention of this invention is a waste water treatment apparatus which processes the organic substance in waste_water | drain, Comprising: At least 1 is provided in the waste water treatment tank which stores the said waste_water | drain, a light source, and the said waste water treatment tank, The said light source A photocatalyst-coated leaky light guide in which a photocatalyst layer containing a photocatalyst is coated on the surface of a leaky light guide that leaks while guiding the light emitted from the light source, and the light emitted from the light source covers the photocatalyst-coated leaky light guide A wastewater treatment device characterized in that the organic matter in the wastewater is decomposed and removed by the photocatalyst.

  A second invention is the waste water treatment apparatus according to the first invention, wherein the leakage light guide has a light guide part for guiding the light.

  According to a third invention, in the second invention, the leakage light guide further has a refractive index of light equal to or higher than that of the light guide unit, and leaks light leaking from the light guide unit. It is the waste water treatment equipment which has a section.

  A fourth invention is the waste water treatment apparatus according to any one of the first to third inventions, wherein the photocatalyst layer is porous.

  A fifth aspect of the invention is the waste water treatment apparatus according to the fourth aspect of the invention, wherein the waste water treatment tank includes an oxygen supply unit that supplies oxygen toward the photocatalyst-coated leakage light guide.

  According to a sixth invention, in any one of the first to fifth inventions, the light collecting means for collecting the light emitted from the light source, the light reflected from the condenser lens, and the light guide. A wastewater treatment apparatus having distribution means for guiding light to a body.

  A seventh invention is the waste water treatment apparatus according to any one of the first to sixth inventions, wherein the light source is visible light, ultraviolet light, or sunlight.

  An eighth invention is the waste water treatment apparatus according to any one of the first to seventh inventions, wherein the light guide section is formed including at least one of quartz glass and plastic.

  A ninth invention is the waste water treatment apparatus according to any one of the first to eighth inventions, wherein the photocatalyst contains at least one of titanium oxide, zinc oxide, cadmium sulfide, and iron oxide.

  According to the present invention, by irradiating light from the inner side to the outer side of the photocatalyst layer through the leaking light guide, light can be efficiently radiated to the photocatalyst layer without waste. It can be efficiently decomposed and removed by the photocatalyst. For this reason, light can be efficiently irradiated to the photocatalyst, and the decomposition performance of the organic matter in the wastewater can be improved.

FIG. 1 is a schematic view of a first waste water treatment apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the photocatalyst-coated leaky light guide. FIG. 3 is a cross-sectional view schematically showing an example of the configuration of the leakage light guide. FIG. 4 is a diagram schematically illustrating a light leakage state in the leakage light guide. FIG. 5 is an explanatory diagram showing the relationship between the film thickness of the photocatalyst layer and the performance of the photocatalyst. FIG. 6 is a cross-sectional view showing another example of the configuration of the leakage light guide. FIG. 7 is a diagram illustrating an example of the arrangement of the photocatalyst-coated leakage light guides. FIG. 8 is a diagram showing an example of another arrangement of the photocatalyst-coated leaky light guide. FIG. 9 is a diagram simply showing the configuration of the second waste water treatment apparatus according to Embodiment 2 of the present invention. FIG. 10 is a diagram simply showing the configuration of the third waste water treatment apparatus according to Embodiment 3 of the present invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the content described in the following Examples. In addition, constituent elements in the embodiments described below include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in the so-called equivalent range. Furthermore, the constituent elements disclosed in the embodiments described below can be appropriately combined.

  The 1st waste water treatment equipment concerning Example 1 of the present invention is explained with reference to drawings. FIG. 1 is a schematic view of a first waste water treatment apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, a first wastewater treatment apparatus 10 </ b> A according to the present embodiment is a wastewater treatment apparatus that treats organic matter in the wastewater 11, a wastewater treatment tank 12 that stores the wastewater 11, a light source 13, and The photocatalyst-coated leaking light guide 17 is provided in the waste water treatment tank 12 and has a photocatalyst layer 16 containing a photocatalyst coated on the surface of a leaky light guide 15 that guides and leaks the light 14 emitted from the light source 13. And an optical fiber (light guide) 18 that guides the light 14 emitted from the light source 13 to the leakage light guide 15.

  For example, waste water 11 discharged from a factory or the like is supplied to the waste water treatment tank 12 through a waste water supply pipe 21 and stored therein. The supply amount of the waste water 11 fed to the waste water treatment tank 12 is adjusted by the control valve V11. Moreover, since the wastewater 11 fed to the wastewater treatment tank 12 is, for example, wastewater discharged from a factory or the like, it contains substances that degrade the photocatalyst such as solids and oil. Therefore, substances that cause deterioration of the photocatalyst contained in the wastewater discharged from factories or the like are removed in advance using a sedimentation tank or a filtration device or the like, and the wastewater 11 from which the above substances and the like are removed is drained. It is fed to the treatment tank 12.

  The optical fiber 18 and the photocatalyst-coated leaking light guide 17 are connected by a fiber adapter 22. The light 14 emitted from the light source 13 is guided to the leakage light guide 15 of the photocatalyst-coated leakage light guide 17 through the optical fiber 18.

  In the wastewater treatment tank 12, a plurality (10 in this embodiment) of the photocatalyst-coated leaky light guides 17 are suspended and provided in a bowl shape. FIG. 2 is a cross-sectional view of the photocatalyst-coated leaking light guide 17. As shown in FIG. 2, the photocatalyst-coated leaky light guide 17 includes a leaky light guide 15 and a photocatalyst layer 16. The leaky light guide 15 is formed in a cylindrical shape, and a photocatalyst is laminated on the surface of the outer wall. The photocatalyst layer 16 is formed as a thin film.

The leaking light guide 15 leaks the light 14 while guiding it. The leakage light guide 15 is formed to include at least one of quartz (SiO ₂ ) glass and plastic excellent in light transmission. The leaky light guide 15 is formed into a fiber by melting and pulling a material containing at least one of SiO ₂ glass and plastic. FIG. 3 is a cross-sectional view schematically showing an example of the configuration of the leakage light guide 15. As shown in FIG. 3, the leaking light guide 15 has a two-layer structure of a light guiding part 15 a that guides the light 14 and a leaking part 15 b that leaks light leaked from the light guiding part 15 a. The refractive index of light of the leakage portion 15b is equal to or higher than that of the light guide portion 15a. For example, when the inner diameter of the light guide 15a of the leakage light guide 15 is amm, the length in the axial direction is Lmm, the refractive index of the light guide 15a is n1, and the refractive index of the leakage 15b is n2, the light guide The difference n1-n2 (Δn) in the refractive index of 15a is set to satisfy the following relational expression (A).
Δn> n2 (a / L) ² (A)

  When the refractive index of the light of the light guide 15a is larger than the refractive index of the light of the leaking portion 15b, the light 14 traveling from the light guide 15a toward the leaking portion 15b is reflected by the leaking portion 15b, and the light guide The light guide unit 15a travels while repeating reflection within 15a. However, since the refractive index of the light of the leaking part 15b is equal to or higher than that of the light guide part 15a, the light 14 traveling from the light guide part 15a toward the leaking part 15b is not reflected by the leaking part 15b and leaked and guided. It will be released to the outside of the body 15.

  FIG. 4 is a diagram schematically illustrating a leakage state of the light 14 in the leakage light guide 15. As shown in FIG. 4, the light 14 guided to the leaking light guide 15 travels in the light guide 15a, and a part of the light 14 travels from the light guide 15a to the leaking part 15b as leaked light 14b. Then, the leakage light 14b passes through the leakage portion 15b without being reflected by the leakage portion 15b, and the leakage light guide 15 can leak the leakage light 14b to the outside of the leakage light guide 15. Thereby, the leakage light 14b can be irradiated to the photocatalyst layer 16.

By irradiating the leakage light 14b from the leakage light guide 15 toward the photocatalyst layer 16, oxygen (O ₂ ) derived from air and water (H ₂ O) derived from the waste water 11 are formed on the surface of the photocatalyst layer 16. However, the photocatalyst reacts as in the following formulas (1) and (2) to generate an oxidant.
^{_{O 2 → O 2 - ··· (}} 1)
H ₂ O → OH ⁻ (2)

The organic matter (C _m H _n ) in the wastewater 11 attached to the photocatalyst layer 16 by the photocatalyst contained in the photocatalyst layer 16 is oxidized by OH ⁻ generated in the wastewater 11 as shown in the following formula (3), and the wastewater 11 can be dissolved and decomposed.
C _m H _n + OH ⁻ → C _m H _{n + 1} O (3)

Heavy metal ions such as Co ²⁺ , Hg ²⁺ , and Fe ²⁺ in the wastewater 11 are reduced by the photocatalyst and can be included in the wastewater 11.

  After the organic matter in the waste water 11 is decomposed by the photocatalyst, it is discharged from the waste water treatment tank 12 through the discharge pipe 24 as the treated water 23, and after heavy metals contained in the waste water 11 are removed, it is discharged to the outside. The discharge amount of the waste water 11 in the waste water treatment tank 12 is adjusted by a control valve V12 provided in the discharge pipe 24.

  The light 14 emitted from the light source 13 can be uniformly applied to all the leakage light guides 15, and can be emitted from the inside to the outside of the photocatalyst layer 16 through each leakage light guide 15. . Therefore, since the light 14 irradiated from the light source 13 can be irradiated from the inner side to the outer side of the photocatalyst layer 16 through all the leakage light guides 15, the light 14 is efficiently and efficiently irradiated onto the photocatalyst layer 16. can do. Thereby, since the light 14 can be efficiently irradiated to the photocatalyst and the organic matter in the wastewater 11 can be efficiently decomposed and removed by the photocatalyst, the decomposition performance of the organic matter in the wastewater 11 can be improved.

  When the film thickness of the photocatalyst layer 16 is increased, the amount of light 14 passing through the photocatalyst layer 16 is reduced, so that the function of the photocatalyst of the photocatalyst layer 16 is lowered. Therefore, the film thickness of the photocatalyst layer 16 is larger than 0 μm and 0.5 μm or less from the viewpoint of enabling the light 14 to pass through the photocatalyst layer 16 and effectively exhibiting the catalytic function of the photocatalyst layer 16. Preferably, it is greater than 0 μm and less than or equal to 0.3 μm. FIG. 5 is an explanatory diagram showing the relationship between the film thickness of the photocatalyst layer 16 and the performance of the photocatalyst. As shown in FIG. 5, the performance of the photocatalyst is not degraded until the film thickness of the photocatalyst layer 16 is 0.3 μm, but the performance of the photocatalyst is degraded when the film thickness of the photocatalyst layer 16 is from 0.3 μm to 0.5 μm. However, the performance of the photocatalyst necessary for decomposing the organic matter in the waste water 11 can be kept effective. When the film thickness of the photocatalyst layer 16 exceeds 0.5 μm, the performance of the photocatalyst further decreases, and the performance of the photocatalyst necessary for decomposing the organic matter in the waste water 11 cannot be maintained effectively. This is because the amount of light 14 passing through the photocatalyst layer 16 changes according to the film thickness of the photocatalyst layer 16, but when the film thickness of the photocatalyst layer 16 exceeds 0.5 μm, the light 14 travels on the surface of the photocatalyst layer 16. This is because it cannot pass sufficiently, and the photocatalytic function of the surface of the photocatalyst layer 16 cannot be sufficiently exhibited. In addition, when the film thickness of the photocatalyst layer 16 is 0.3 μm or less, the light 14 can almost pass through the surface of the photocatalyst layer 16, so that the performance of the photocatalyst is hardly deteriorated. Therefore, the film thickness of the photocatalyst layer 16 is preferably greater than 0 μm and not greater than 0.5 μm, and more preferably greater than 0 μm and not greater than 0.3 μm.

Examples of the material used as the photocatalyst include titanium oxide (TiO ₂ ), zinc oxide (ZnO), cadmium sulfide (CdS), and iron oxide. The materials used as the photocatalyst can be used alone or in combination of two or more. As a material used as a photocatalyst, it is particularly preferable to use TiO ₂ . When TiO ₂ is used as the photocatalyst, it is particularly preferable to use TiO ₂ having an anatase type crystal structure excellent in catalytic performance.

As a method for producing the photocatalyst-coated leaking light guide 17, for example, there is a method in which the leaking light guide 15 is immersed in a solution that is a raw material for the photocatalyst such as TiO ₂ , pulled up, and then subjected to heat treatment or the like.

  The photocatalyst layer 16 may be filled with a photocatalyst in a porous body having a plurality of pores. As a result, the surface area of the photocatalyst layer 16 is increased, and the contact efficiency between the wastewater 11 and the photocatalyst layer 16 can be further increased, so that the organic matter in the wastewater 11 can be decomposed more efficiently by the photocatalyst layer 16. . At this time, a laminate obtained by coating the leakage light guide 15 with a material that becomes a porous body is baked to form a porous body having a plurality of pores, and a photocatalyst is supported on the porous body. A photocatalytic layer is produced.

  The leaking light guide 15 is not particularly limited as long as it transmits the light 14 and can coat a material used as a photocatalyst.

  The leakage light guide 15 has a two-layer structure of a light guide portion 15a and a leakage portion 15b. However, the present embodiment is not limited to this, and the leakage light guide 15 leaks the light 14 through the leakage guide. It suffices that light can be leaked to the outside of the leaking light guide 15 and irradiated to the photocatalyst layer 16 while being guided to the tip of the light body 15. FIG. 6 is a cross-sectional view illustrating another example of the configuration of the leakage light guide 15. As shown in FIG. 6, the leakage light guide 15 includes only the light guide portion 15 a, and guides the light 14 incident from the optical fiber 18 to the distal end portion of the leakage light guide 15, while leaking the light guide 15. The light 14 directed to the outside may be irradiated onto the photocatalyst layer 16 as it is.

  The shape of the leaking light guide 15 is a columnar shape, but is not limited to this. For example, in addition to the columnar shape, the cross-sectional shape when viewed from the axial direction of the leaking light guide 15 is a triangular shape or a square shape. Such as a polygonal shape or a spiral shape. By making the shape of the leakage light guide 15 spiral, the surface area of the leakage light guide 15 can be increased, so that the amount of the photocatalyst that can be coated on the surface of the leakage light guide 15 can be increased. For this reason, the decomposition | disassembly performance of the organic substance in the waste_water | drain 11 can be improved.

  The plurality of photocatalyst-coated leaky light guides 17 are arranged so that the photocatalyst-coated leaky light guides 17 do not contact each other. FIG. 7 is a diagram illustrating an example of the arrangement of the photocatalyst-coated leakage light guides 17. As shown in FIG. 7, the plurality of photocatalyst-coated leaking light guides 17 may be arranged in a hexagonal lattice in the waste water treatment tank 12. The plurality of photocatalyst-coated leaky light guides 17 are arranged in a hexagonal shape in the wastewater treatment tank 12 so that the contact efficiency between the drainage 11 and the photocatalyst-coated leaky light guides 17 is different from each other. Therefore, the organic matter in the waste water 11 can be more efficiently processed by the photocatalyst-coated leaky light guide 17. FIG. 8 is a diagram illustrating an example of another arrangement of the photocatalyst-coated leaky light guide 17. As shown in FIG. 8, the plurality of photocatalyst-coated leakage light guides 17 may be arranged in four directions at equal intervals in the wastewater treatment tank 12. Further, the arrangement method of the photocatalyst-coated leaky light guides 17 is not particularly limited, and the photocatalyst-coated leaky light guides 17 may be arranged so as not to contact each other, as shown in FIGS. There is no need to arrange them regularly.

  Therefore, by arranging the plurality of photocatalyst-coated leaky light guides 17 in the wastewater treatment tank 12 so as not to contact each other, the contact efficiency between the drainage 11 and each photocatalyst-coated leaky light guide 17 is substantially uniform, Each photocatalyst-coated leaky light guide 17 can efficiently decompose the organic matter in the drainage 11.

  In addition, the plurality of photocatalyst-coated leaking light guides 17 are simply provided in the wastewater treatment tank 12 so as to be easily installed and require little maintenance, so that the operating cost required for the equipment can be reduced. At the same time, the apparatus can be easily operated.

Furthermore, because of the photocatalytic effect of TiO ₂ , microorganisms and scales do not adhere to the surface of the photocatalyst-coated leaking light guide 17, and the photocatalytic performance of the photocatalyst is not deteriorated. Can be done.

  The number, outer diameter, and length of the photocatalyst-covered leaking light guides 17 that are suspended from the wastewater treatment tank 12 are such that part or all of the photocatalyst-covered leaky light guides 17 are included in the wastewater 11 in the wastewater treatment tank 12. What is necessary is just to be immersed, and it can change suitably according to the flow volume of the waste_water | drain 11, and the density | concentration of the organic substance contained in the waste_water | drain 11.

  The discharge pipe 24 may be provided with a circulation passage for extracting the treated water 23 and circulating it to the waste water treatment tank 12. If organic matter or the like remains in the treated water 23, the treated water 23 is extracted from the circulation passage and circulated to the wastewater treatment tank 12, so that the photocatalyst-coated leaking light guide 17 again causes the treated water 23 to enter the wastewater 11. The organic matter contained can be decomposed. The organic matter contained in the waste water 11 is decomposed again by the photocatalyst-coated leaky light guide 17, so that the concentration of the organic matter contained in the treated water 23 can be further lowered and discharged.

In the first waste water treatment apparatus 10A according to the present embodiment, the waste water 11 is directly stored in the waste water treatment tank 12, but ozone (O ₃ ) or peroxidation is previously stored in the waste water 11 in the waste water supply pipe 21. Hydrogen (H ₂ O ₂ ) may be supplied. Further, O ₃ or H ₂ O ₂ may be supplied to the waste water 11 stored in the waste water treatment tank 12. By mixing O ₃ or H ₂ O ₂ in the waste water 11, the oxidant in the waste water 11 can be increased, so that the decomposition of the organic matter in the waste water 11 can be further promoted.

  Thus, according to the first wastewater treatment apparatus 10A according to the present embodiment, by irradiating the light 14 from the inside of the photocatalyst layer 16 through the leakage light guide 15 of the photocatalyst-coated leakage light guide 17, Since the light 14 can be efficiently used without permission, the photocatalytic function of the photocatalyst layer 16 can be sufficiently exerted, and the decomposition performance of the organic matter in the waste water 11 can be improved.

  In the first wastewater treatment apparatus 10A according to the present embodiment, the case where the light 14 from the light source 13 is visible light has been described. However, the present embodiment is not limited to this, and a mercury (Hg) lamp is used. Any light can be used as long as the photocatalytic performance of the photocatalyst such as ultraviolet light (UV) and sunlight can be effectively exhibited.

If the TiO ₂ layer of a photocatalytic layer 16 from TiO _2, even when the light source 13 is irradiated with UV, oxidants from atmosphere containing oxygen (O ₂₎ and water from the waste water 11 (H ₂ O) derived from the air Is generated and the organic matter can be oxidatively decomposed. Since UV must be shorter than 380 nm to activate TiO ₂ , more oxidant can be generated using UV rather than using light 14 from light source 13. . Therefore, when the photocatalyst layer 16 is a TiO ₂ layer, a UV lamp is used as the light source 13, and the UV light is emitted from the leakage light guide 15 toward the drainage 11, whereby the catalyst efficiency of TiO ₂ can be improved. Therefore, the ability to decompose organic substances can be further improved, and a sufficient treatment effect of the waste water 11 can be obtained. For this reason, even if the concentration of the organic matter in the waste water 11 is high, the organic matter can be efficiently decomposed and removed and discharged as treated water 23.

  In the first wastewater treatment apparatus 10A according to the present embodiment, the wastewater discharged from a factory or the like has been described, but the present invention is not limited to this, and is for households having a relatively low organic matter concentration. It can also be used for drainage.

A second wastewater treatment apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 9 is a diagram simply showing the configuration of the second waste water treatment apparatus according to Embodiment 2 of the present invention. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted. As shown in FIG. 9, the second waste water treatment apparatus 10B according to the present embodiment includes a photocatalyst-coated leaking light guide in the waste water treatment tank 12 of the first waste water treatment apparatus 10A according to the first embodiment shown in FIG. 17 has an oxygen supply unit 32 for supplying oxygen (O ₂ ) 31 toward the surface 17. The oxygen supply unit 32 supplies oxygen 31 into the drainage 11 from the lower end side of the photocatalyst-coated leakage light guide 17 toward the photocatalyst-coated leakage light guide 17. The supply amount of oxygen 31 supplied into the waste water treatment tank 12 is adjusted by a control valve V13.

Water molecules in water are decomposed by the photocatalyst as in the above formula (2) to generate OH radicals (OH ⁻ ). By supplying oxygen 31 into the waste water 11, the photocatalyst can generate the following formula ( As in 4), OH ⁻ can be further generated in the waste water 11.
1 / 2O ₂ + H ⁺ → OH ⁻ (4)

Due to the OH ⁻ generated in the waste water 11, the solid matter in the waste water 11 or the organic matter (C _m H _n ) adhering to the photocatalyst surface can be dissolved in the waste water 11 as in the above formula (3).

Heavy metal ions such as Co ²⁺ , Hg ²⁺ , and Fe ²⁺ in the wastewater 11 are reduced by the photocatalyst and adhere to the surface of the photocatalyst layer 16, but by supplying oxygen 31 into the wastewater 11, the photocatalyst layer Heavy metal ions adhering to the surface of 16 can be oxidized by oxygen 31 and dissolved in the waste water 11 to be removed.

  Moreover, since air bubbles are generated in the waste water 11 by supplying the oxygen 31 into the waste water 11, it is possible to promote the removal of organic substances and heavy metals attached to the photocatalyst layer 16 by the air bubbles.

  Therefore, according to the second wastewater treatment apparatus 10B according to the present embodiment, the organic matter adhered to the photocatalyst layer 16 by the oxygen 31 supplied from the oxygen supply unit 32 into the wastewater 11 toward the photocatalyst-coated leaking light guide 17. Since heavy metals and heavy metals can be removed, it is possible to prevent performance degradation of the photocatalytic function of the photocatalytic layer 16.

In the second wastewater treatment apparatus 10B according to the present embodiment, the leakage light guide 15 is irradiated with visible light as the light 14 from the light source 13, but the present embodiment is not limited to this. Instead, UV light may be emitted from the light source 13. When irradiating UV from the light source 13, the oxygen 31 supplied from the oxygen supply unit 32 absorbs light having a wavelength of about 185 nm to 250 nm included in the UV of the light source 13, and thus ozone (O ₃ ) Generate.
O ₂ + O → O ₃ (5)

By irradiating UV from the light source 13, UV is irradiated into the drainage 11 through the leaking light guide 15. As a photocatalyst layer 16, when the TiO ₂ layer consisting of TiO _2, ozone generated from the oxygen in the waste water 11 receives light of a wavelength of 185 nm (O ₃₎ is represented by the following formula in the surface of the TiO ₂ layer (6 ) To produce an oxidant and oxidatively decompose organic matter. In addition, by making the carrier of the photocatalyst layer 16 porous, the surface area of the TiO ₂ layer is increased, and more oxidant can be generated on the surface of the TiO ₂ layer, thus promoting the oxidative decomposition of organic matter. In addition, organic substances can be oxidatively decomposed more efficiently.
O ₃ → O ・ + O ^2-・ ・ ・ （６）

Therefore, by irradiating UV from the light source 13, ozone generated from the oxygen 31 supplied into the wastewater treatment tank 12 is decomposed on the surface of the photocatalyst layer 16 to generate O · and O ²⁻ . Thereby, since the oxidizing agent which contacts the waste_water | drain 11 can be increased and the oxidative decomposition of organic substance can be accelerated | stimulated, the decomposition | disassembly efficiency of organic substance can be improved further, the organic substance in the waste_water | drain 11 can be decomposed | disassembled more efficiently, A sufficient treatment effect of the drainage 11 can be obtained. In addition, oxygen that has not changed to ozone also generates an oxidant by the photocatalyst of the photocatalyst layer 16, and therefore can be used for decomposition of organic matter. Furthermore, since it can be used without using an apparatus for generating ozone, the cost can be further reduced.

  The 3rd waste water treatment equipment concerning Example 3 of the present invention is explained with reference to drawings. FIG. 10 is a diagram simply showing the configuration of the third waste water treatment apparatus according to Embodiment 3 of the present invention. In addition, about the member similar to Example 1, 2, the same code | symbol is attached | subjected and the description is abbreviate | omitted. As shown in FIG. 10, the third wastewater treatment apparatus 10C according to the present embodiment reflects the sunlight 41 from the sun on the first wastewater treatment apparatus 10A according to the first embodiment shown in FIG. A plate (light condensing means) 42 and a distributor (distributing means) 43 that receives sunlight 41 reflected by the reflecting plate 42 and guides it to the plurality of optical fibers 18 are provided. The plurality of optical fibers 18 are bundled by a holder 44.

  The reflection plate 42 is a reflection plate having a parabolic curved surface that is curved in the direction in which the sunlight 41 is irradiated. The sunlight 41 incident on the reflecting plate 42 is collected by the reflecting plate 42 at one point on the light receiving surface of the distributor 43 or around it, and is received by the distributor 43. The distributor 43 is connected to the plurality of optical fibers 18, transmits sunlight 41 collected by the reflector 42 to each optical fiber 18 connected to the distributor 43, and the photocatalyst-coated leakage guide is transmitted via the optical fiber 18. The light is guided to the light body 17.

  Therefore, according to the third wastewater treatment apparatus 10 </ b> C according to the present embodiment, it is possible to increase the amount of received light of the sunlight 41 and increase the amount of light guided to the photocatalyst-coated leakage light guide 17. For this reason, since the light quantity leaked from the leaking light guide 15 to the photocatalyst layer 16 can be increased, the reaction efficiency of the photocatalyst in the photocatalyst layer 16 is improved, and the removal efficiency of organic substances and metal ions in the waste water 11 is improved. be able to.

  In the third wastewater treatment apparatus 10C according to the present embodiment, the reflection plate 42 that reflects the sunlight 41 and collects it on the distributor 43 is used as the light collecting means. The light condensing unit is not limited as long as it can collect light from a light source such as sunlight 41 on the distributor 43. As the light condensing means, for example, a condensing lens that can transmit sunlight 41 may be used, and the sunlight 41 transmitted through the condensing lens may be condensed on the distributor 43.

  In the third wastewater treatment apparatus 10C according to the present embodiment, the sunlight 41 is concentrated on the distributor 43 by one reflector 42, but the present embodiment is not limited to this. Alternatively, the light may be condensed on the distributor 43 using a plurality of reflecting plates 42.

  In the third wastewater treatment apparatus 10 </ b> C according to the present embodiment, the entire apparatus may be surrounded by a reflecting mirror having a high reflectivity, received by the reflection plate 42, and sunlight 41 may be collected. By surrounding the reflector 42 with a reflector having high reflectance, the light collection efficiency of the sunlight 41 can be improved, and the external sunlight 41 can be used more efficiently.

  As described above, the wastewater treatment apparatus according to the present invention can efficiently decompose organic matter in wastewater, and thus is suitable for use as a wastewater treatment apparatus that decomposes organic matter contained in wastewater.

10A to 10C First to third wastewater treatment apparatuses 11 Wastewater 12 Wastewater treatment tank 13 Light source 14 Light 15 Leakage light guide 15a Light guide portion 15b Leakage portion 16 Photocatalyst layer 17 Photocatalyst-coated leaky light guide 18 Optical fiber (light guide) body)
21 Drain supply pipe 22 Fiber adapter 23 Treated water 024 Drain pipe 31 Oxygen (O ₂ )
32 Oxygen supply part 41 Sunlight 42 Reflector (light condensing means)
43 Distributor (Distributing means)
44 holder

Claims (9)

A wastewater treatment device for treating organic matter in wastewater,
A wastewater treatment tank for storing the wastewater;
A light source;
A photocatalyst-coated leaky light guide provided with a photocatalyst layer containing a photocatalyst on the surface of a leaky light guide that is provided in the wastewater treatment tank and leaks while guiding light emitted from the light source;
A light guide that guides the light emitted from the light source to the photocatalyst-coated leakage light guide,
A wastewater treatment apparatus, wherein organic matter in the wastewater is decomposed and removed by the photocatalyst. In claim 1,
The wastewater treatment apparatus, wherein the leaking light guide includes a light guide unit that guides the light. In claim 2,
The wastewater treatment apparatus, wherein the leaking light guide further includes a leaking part that has a refractive index of light equal to or higher than that of the light guiding part and leaks light leaked from the light guiding part. In any one of Claims 1 thru | or 3,
A wastewater treatment apparatus in which the photocatalyst layer is porous. In claim 4,
A wastewater treatment apparatus having an oxygen supply unit for supplying oxygen toward the photocatalyst-coated leaking light guide in the wastewater treatment tank. In any one of Claims 1 thru | or 5,
Light condensing means for condensing the light emitted from the light source;
A wastewater treatment apparatus having distribution means for receiving light reflected from the condenser lens and guiding the light to the light guide. In any one of Claims 1 thru | or 6,
A wastewater treatment apparatus, wherein the light source is visible light, ultraviolet light, or sunlight. In any one of Claims 1 thru | or 7,
A wastewater treatment apparatus in which the light guide section is formed to include at least one of quartz glass and plastic. In any one of Claims 1 thru | or 8,
A wastewater treatment apparatus, wherein the photocatalyst contains at least one of titanium oxide, zinc oxide, cadmium sulfide, and iron oxide.

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