JP2010234209A - Ultraviolet ray oxidation treatment apparatus and ultraviolet ray oxidation treatment method for water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultraviolet ray oxidation treatment apparatus capable of obtaining treated water with an extremely low TOC concentration while preventing a short pass of water to be treated in an ultraviolet ray oxidation treatment apparatus. <P>SOLUTION: A reflux plate 11 is composed of a ring-like reflux plate body part 12 and a seal member 13 disposed on the outer periphery of the reflux plate body part 12. The reflux plate body part 12 is open in the center, spaced from a quartz protective tube 6, and is formed with a recessed portion in the outer periphery by a small-diameter portion 12B of a middle portion thereof and a large-diameter portion 12A of each of both side face portions thereof. The seal member 13 is a ring-shaped body formed from a material such as a synthetic resin or an elastomer with small friction against stainless steel and has an outer diameter substantially equal to the inside diameter of a cylinder 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ultraviolet oxidation treatment apparatus for decomposing organic substances and hardly decomposable substances in water, and particularly to an ultraviolet oxidation treatment apparatus having a high decomposition treatment capacity and high treatment efficiency. The present invention also relates to an ultraviolet oxidation treatment method for decomposing organic substances and hardly decomposable substances in water, and more particularly to an ultraviolet oxidation treatment method having high decomposition treatment capacity and high treatment efficiency.

  Conventionally, ultraviolet rays are used for the purpose of decomposing and sterilizing organic substances and hardly decomposable substances in water. In particular, low-pressure ultraviolet discharge lamps are widely used because they emit ultraviolet light having a main wavelength of 254 nm and ultraviolet light having a short wavelength of 220 nm or less at the same time. In the decomposition reaction using this low-pressure ultraviolet discharge lamp, ultraviolet rays having a short wavelength of 220 nm or less have strong energy, and thus are effective for decomposing organic substances in water. The mechanism of decomposition of the organic matter by the short wavelength ultraviolet ray is that a water radical is first dissociated with the energy of the short wavelength ultraviolet ray of 220 nm or less to generate a hydroxy radical (reaction formula (1)).

  Since the hydroxy radicals generated here are strong oxidants, they undergo carbon dioxide, water, organic acids as reaction intermediates, and excess products as by-products through a chain oxidation reaction with organic substances in water as shown below. It is widely known that hydrogen oxide is produced (reaction formula (2)).

  Furthermore, when hydrogen peroxide produced as a by-product in the above reaction is decomposed by ultraviolet light having a wavelength of 254 nm, which is the main wavelength of a low-pressure ultraviolet discharge lamp, a hydroxy radical is generated (reaction formula (3)). This reaction is widely known as AOP (accelerated oxidation process), and the hydroxy radical generated in the reaction formula (3) is an organic substance similar to the hydroxy radical generated from water molecules in the reaction of the above reaction formula (1). Causes oxidative degradation reaction.

In order to efficiently perform organic matter treatment in water by such ultraviolet oxidation, in the reaction mechanism of the above reaction formulas (1) to (3),
(I) Irradiation of water to be treated with short-wavelength ultraviolet light having a wavelength of 220 nm or less (II) Two conditions of ensuring reaction time so that ultraviolet light with a wavelength of 254 nm can also be utilized are important.

  However, these two conditions are contradictory conditions in actual device implementation. That is, it is generally a low-pressure ultraviolet discharge lamp that can simultaneously and economically obtain ultraviolet light having a wavelength of 220 nm or less and ultraviolet light having a wavelength of 254 nm. In this low-pressure ultraviolet discharge lamp, the main wavelength to be emitted is 254 nm, and at the same time, it is possible to obtain ultraviolet light having a wavelength of 185 nm, which is about 20% of the output of 254 nm. However, ultraviolet rays with a wavelength of 185 nm are strongly absorbed by water, and are absorbed almost completely with an optical path length of 10 mm or less even in ultrapure water containing almost no impurities. That is, the range in which the ultraviolet ray having a wavelength of 185 nm reaches is 10 mm or less from the outer surface of the quartz protective tube, and no hydroxyl radical is generated in water flowing away from it. Therefore, it is conceivable to reduce the thickness of all the water in the flow path portion of the ultraviolet oxidation treatment apparatus to 10 mm or less, but this reduces the internal capacity of the apparatus, and the residence time (reaction time) in the irradiation apparatus is reduced. It can be secured only for an extremely short time.

  For this reason, an ultraviolet oxidation processing apparatus in which a reflux plate is provided in the outer cylinder (cylinder) so as to satisfy these conflicting conditions as much as possible is used in practice. An example of an ultraviolet oxidation treatment apparatus provided with such a reflux plate is shown in FIGS. The ultraviolet oxidation treatment apparatus 1 is accommodated in a cylindrical stainless steel cylinder 2 having a treated water inlet 3 serving as a water supply section on one side and a treated water outlet 4 serving as a drainage section on the other side, and a quartz protective tube 6. Thus, it has a basic structure consisting of a low-pressure ultraviolet discharge lamp 5 isolated in a liquid-tight state. In the cylinder 2, a plurality of annular reflux plates 8 a to 8 e fixed to the pair of rods 7 at a predetermined interval are arranged. Reference numerals 9a and 9b are end plates fixed in a liquid-tight state by an O-ring (not shown).

  In the apparatus as described above, when the water to be treated W is introduced from the treated water inlet 3, ultraviolet light is irradiated from the low-pressure ultraviolet discharge lamp 5 and flows toward the treated water outlet 4. At this time, since the reflux plates 8a to 8e are arranged in the middle, the treated water W is prevented from short-passing between the treated water inlet 3 and the treated water outlet 4, and the vicinity of the low-pressure ultraviolet discharge lamp 5 is prevented. While flowing, it is possible to secure a residence time. In the removal of organic substances in water by ultraviolet oxidation, as described above, organic acid and carbon dioxide as reaction intermediates are generated, and therefore an ion exchange treatment apparatus is usually disposed downstream for the purpose of removing these. It is.

  However, in this ultraviolet oxidation processing apparatus 1, a plurality of annular reflux plates 8 a to 8 e fixed to the pair of rods 7 are inserted into the cylindrical stainless steel cylinder 2. In order to apply the plates 8a to 8e to an ultrapure water treatment apparatus or the like, it is inevitable that the plates 8a to 8e are made of metal such as stainless steel from the viewpoint of elution resistance and ultraviolet resistance. For this reason, if the gap (clearance) between the outer edges of the reflux plates 8a to 8e and the inner surface of the cylinder 2 is set to the limit, the stainless steels come into contact with each other. Stainless steel has a large frictional force, and the return plates 8a to 8e cannot be stored in the cylinder 2. Therefore, a certain amount of clearance is secured between the outer edges of the return plates 8a to 8e and the inner surface of the cylinder 2. I have to.

  In the ultraviolet oxidation treatment apparatus 1 using such a conventional reflux plate, a relatively large pressure loss occurs in the reflux plates 8a to 8e inside the cylinder 2 when the flow rate of the treated water is large and the flow rate is high. Therefore, most of the water to be treated W passes through the flow path between the quartz protective tube 6 and the reflux plates 8a to 8e having a larger gap than the clearance portion between the reflux plates 8a to 8e and the cylinder 2 described above. The problem does not become obvious. However, when obtaining treated water with a very low TOC concentration, the flow rate is lowered by reducing the treated water flow rate, so that the pressure loss generated in the reflux plates 8a to 8e is also reduced. For this reason, the to-be-processed water W which passes the inside of the cylinder 2 is an area of the clearance area between the reflux plates 8a-8e and the cylinder 2, and the area of the flow path between the reflux plates 8a-8e and the quartz protective tube 6. The ratio of the short path is increased as compared with the case where the flow is divided so as to approximate the ratio and processing is performed at a high flow rate. Since the portion of the clearance between the reflux plates 8a to 8e and the inner surface of the cylinder 2 is farthest from the low-pressure ultraviolet discharge lamp 5, the water to be treated W passing there has the shortest wavelength and the highest oxidation ability. Almost no irradiation with ultraviolet rays of 185 nm is possible. For this reason, the to-be-processed water W which short-passes the clearance part between the recirculation | reflux plates 8a-8e and the inner surface of the cylinder 2 cannot receive sufficient ultraviolet-ray oxidation, but remains without removing a TOC component. There was a problem that the TOC concentration of the whole water could not be lowered sufficiently.

  In particular, this short path problem is serious in order to achieve a TOC concentration of less than 1 μg / L of treated water (ultra pure water) required for an ultra pure water treatment apparatus in recent years.

  In order to solve such problems, various ultraviolet oxidation treatment apparatuses have been proposed. For example, Patent Document 1 discloses an ultraviolet oxidation processing apparatus using a discharge lamp having an arc tube made of synthetic quartz glass for the purpose of increasing the maintenance rate of the output of ultraviolet light having a wavelength of 240 nm or less. Patent Document 2 discloses an ultraviolet oxidation treatment apparatus in which a dam plate is fixed to the inner surface of a cylinder for the purpose of retaining water to be treated. Patent Document 3 discloses an ultraviolet oxidation treatment apparatus in which a stirring plate is fixed to the inner surface of a cylinder for the purpose of giving a swirl flow to water to be treated. Furthermore, Patent Document 4 discloses an ultraviolet oxidation treatment apparatus in which a large number of ultraviolet lamps are provided in a square cross section and a mixing plate is installed so that water to be treated flows in a direction perpendicular to the ultraviolet lamp.

JP 2003-144912 A JP 10-43753 A JP 2003-24934 A Japanese Patent No. 2696636

  However, although the ultraviolet oxidation processing apparatus described in Patent Document 1 can increase the maintenance rate of the output of ultraviolet light, a short in the clearance between the reflux plates 8 a to 8 e of the water to be treated W and the inner surface of the cylinder 2. There is a problem that the path cannot be prevented.

  In addition, the ultraviolet oxidation treatment apparatus described in Patent Documents 2 and 3 directly fixes the reflux plate to the cylinder body by welding or the like, and the quartz protective tube is complicated and expensive to manufacture. There is a problem in that it becomes difficult to remove the debris in the cylinder when it is damaged.

  Furthermore, the ultraviolet oxidation treatment apparatus described in Patent Document 4 has a rectangular reaction vessel, and is inferior in pressure resistance required for a water treatment apparatus. Therefore, it is conceivable to increase the thickness of the container, but in order to ensure the pressure resistance equivalent to that of the cylinder (cylindrical) shape, the thickness of the container increases, which not only increases the weight of the device but also increases the cost. There is a problem that handling becomes difficult. In addition, in the cylindrical shape, it is difficult to install the mixing plate itself so that the water to be treated flows uniformly at right angles to the ultraviolet lamp.

  Thus, conventionally, there has been no ultraviolet oxidation treatment apparatus that can reliably obtain ultrapure water having a TOC concentration of less than 1 μg / L with a simple and practical structure.

  The present invention has been made in view of the above problems, and an ultraviolet oxidation treatment apparatus capable of preventing a short pass of treated water in the ultraviolet oxidation treatment apparatus and obtaining treated water having an extremely low TOC concentration. And an ultraviolet oxidation treatment method for water.

  In order to solve the above problems, firstly, the present invention includes an outer cylindrical body in which a tubular low-pressure ultraviolet discharge lamp is accommodated, and water flows from one end to the other end around the low-pressure ultraviolet discharge lamp, In the ultraviolet oxidation processing apparatus having a plurality of reflux plates provided in the outer cylinder and spaced apart from the low-pressure ultraviolet discharge lamp in the outer circumferential direction of the low-pressure ultraviolet discharge lamp, the reflux plate includes the outer cylinder An ultraviolet oxidation processing apparatus characterized by having a seal portion that seals between the inner surface of the first and second inner surfaces (claim 1).

  According to the above invention (invention 1), by having the seal portion that seals between the reflux plate and the inner surface of the outer cylinder, the clearance between the reflux plate and the outer cylinder is substantially eliminated. In the process of supplying treated water from one end (water supply part) of the outer cylinder and discharging it from the other end (drainage part), the treated water flows out without being exposed to sufficient ultraviolet radiation through the clearance part. The “leakage flow” can be prevented, and ultrapure water having an extremely low organic substance concentration can be obtained. As a result, since the water to be treated is sufficiently irradiated with the low-pressure ultraviolet discharge lamp, a high effect can be obtained in the decomposition and removal of the hardly decomposable substance.

  In the said invention (invention 1), it is preferable that the said seal part is a structure which does not receive the irradiation of the ultraviolet-ray from the said low voltage | pressure ultraviolet discharge lamp directly (invention 2).

  According to the above invention (Invention 2), even if the sealing portion is made of a synthetic resin, an elastomer or the like, it is possible to prevent deterioration due to ultraviolet irradiation from the low-pressure ultraviolet discharge lamp.

  In particular, it is preferable that the reflux plate has an annular shape, and the reflux plate includes an annular reflux plate main body portion and a seal portion disposed on the outer periphery of the reflux plate main body portion. ).

  According to the above inventions (inventions 3 and 4), since the seal portion is disposed on the outer periphery of the annular reflux plate main body portion, the seal portion closes the clearance between the reflux plate and the outer cylindrical body. The seal portion can prevent deterioration due to ultraviolet irradiation from the low-pressure ultraviolet discharge lamp.

  Furthermore, in the said invention (invention 1-4), it is preferable that the said seal part consists of material which has tolerance with respect to the ultraviolet-ray irradiated from the said low pressure ultraviolet discharge lamp (invention 5). Thereby, it is possible to completely prevent the seal portion from being deteriorated due to ultraviolet irradiation or the like from the low-pressure ultraviolet discharge lamp.

  Second, the present invention provides an ultraviolet oxidation treatment method for water, characterized in that the ultraviolet oxidation treatment of water is performed using the ultraviolet oxidation treatment apparatus according to the above inventions (inventions 1 to 5). Item 6).

  According to the above invention (invention 6), by having the seal portion that seals between the reflux plate and the inner surface of the outer cylinder, the clearance between the reflux plate and the outer cylinder is substantially eliminated. In the process of supplying water to be treated from one end (water supply part) of the outer cylinder and discharging from the other end (drainage part), the water to be treated will flow out without receiving sufficient ultraviolet radiation through the clearance part. “Leakage flow” can be prevented, and ultrapure water having an extremely low concentration of organic substances can be obtained. As a result, since the water to be treated is sufficiently irradiated with ultraviolet rays from the low-pressure ultraviolet discharge lamp, a high effect can be obtained in the decomposition and removal of the hardly decomposable substance.

  According to the present invention, the water to be treated passes through the clearance portion of the reflux plate of the ultraviolet oxidation processing apparatus by providing the sealing portion as a filling for eliminating the clearance portion between the inner surface of the cylinder and the inner surface of the cylinder. By doing so, it is possible to prevent a “leakage flow” that flows out from the ultraviolet oxidation treatment apparatus without receiving sufficient ultraviolet irradiation, and thus ultrapure water having an extremely low organic substance concentration can be obtained. Moreover, a high effect can be obtained also in the decomposition and removal of the hardly decomposable substance.

It is a top view which shows the reflux plate of the ultraviolet-ray oxidation processing apparatus which concerns on 1st embodiment of this invention. It is a side view which shows the reflux plate of the ultraviolet-ray oxidation processing apparatus which concerns on said 1st embodiment. It is an expanded sectional view showing the ultraviolet oxidation treatment device concerning the first embodiment. It is a top view which shows the reflux plate of the ultraviolet-ray oxidation processing apparatus which concerns on 2nd embodiment of this invention. It is a side view which shows the reflux plate of the ultraviolet-ray oxidation processing apparatus which concerns on said 2nd embodiment. It is a longitudinal cross-sectional view which shows the reflux plate of the ultraviolet-ray oxidation processing apparatus which concerns on said 2nd embodiment. It is an expanded sectional view which shows the ultraviolet-ray oxidation processing apparatus which concerns on said 2nd embodiment. It is a top view which shows the reflux plate of the ultraviolet-ray oxidation processing apparatus which concerns on 3rd embodiment of this invention. It is sectional drawing which shows the reflux plate of the ultraviolet-ray oxidation processing apparatus which concerns on said 3rd embodiment. It is an expanded sectional view showing the ultraviolet oxidation processing device concerning a 4th embodiment of the present invention. It is a flowchart which shows the ultraviolet-ray oxidation processing system for a test. It is sectional drawing which shows the conventional ultraviolet-ray oxidation processing apparatus schematically. It is a perspective view which shows roughly the reflux plate of the conventional ultraviolet oxidation processing apparatus.

  Hereinafter, a first embodiment of an ultraviolet oxidation processing apparatus of the present invention will be described in detail with reference to the drawings.

  The ultraviolet oxidation processing apparatus according to the present embodiment basically has the same configuration as the conventional ultraviolet oxidation processing apparatus 1 shown in FIGS. 12 and 13 described above except for the reflux plate. The same reference numerals are assigned and detailed description thereof is omitted.

  1 to 3, the reflux plate 11 includes an annular reflux plate main body 12 and a seal member 13 as a seal portion disposed on the outer periphery of the reflux plate main body 12. In FIG. 1, reference numeral 14 denotes an insertion hole into which the pair of rods 7 are inserted.

  Here, the reflux plate body 12 is made of stainless steel and has a shape like a bobbin of a sewing machine or a pulley of a V-belt, and has a center of about 10 mm or less from the quartz protective tube 6, particularly 3 to 10 mm. An opening having a diameter that is separated by a certain degree is formed, and in the axial direction, a concave portion is formed at an outer peripheral end portion by a small-diameter portion 12B in the middle portion and a large-diameter portion 12A in both side surface portions. The reflux plate main body 12 may be one in which the small-diameter portion 12B and the large-diameter portion 12A are integrally formed, or may be a separate molded body that is integrally assembled with screws or the like.

  The seal member 13 is provided in the concave portion (the outer peripheral surface of the small diameter portion 12B) of the reflux plate main body portion 12 as described above. The seal member 13 is preferably made of a synthetic resin, an elastomer, or the like having a small friction with stainless steel, and has an outer diameter that is substantially equal to the inner diameter of the cylinder 2 and has elasticity. Specifically, an O ring, a backup ring, or the like can be used. The synthetic resin or elastomer constituting the seal member 13 is not particularly limited as long as it has water elution resistance, but preferably has inertness or high durability against ultraviolet rays. Moreover, what provided the light shielding layer by the material inactive or highly durable with respect to ultraviolet rays like a metal or DLC (diamond-like carbon) on the surface can also be used suitably.

  In the reflux plate 11 as described above, the rods 7 and 7 are inserted into the insertion holes 14 and 14, and a plurality of plates (5 in this embodiment) are fixed to the rods 7 and 7 at a predetermined interval. Then, with the end plates 9a and 9b and the quartz protective tube 6 not attached, the rod 7 and the reflux plate 11 are pushed into the cylinder 2 and temporarily fixed, and then the end plates 9a and 9b are attached, 7 and the reflux plate 11 are fixed, and then the ultraviolet oxidation treatment apparatus is assembled in the order of inserting the quartz protective tube 6.

  Here, since a material capable of sufficiently reducing the friction with the stainless steel is selected as the seal member 13, the clearance between the reflux plate main body 12 and the seal member 13 and between the seal member 13 and the inner surface of the cylinder 2 is selected. Can be loaded with a plurality of reflux plates 11 connected by rods 7 in the cylinder 2, and can be taken out as necessary.

  The operation of the ultraviolet oxidation processing apparatus according to this embodiment having the reflux plate 11 as described above will be described. As shown in FIG. 3, the to-be-treated water W introduced from the treated water inlet 3 passes through the flow path between the quartz protective tube 6 and the reflux plate 11a and flows into the irradiation space S. Since this irradiation space S is partitioned by the two reflux plates 11a and 11b, the water W to be treated stays here, and after securing a sufficient reaction time by the ultraviolet irradiation from the low-pressure ultraviolet discharge lamp 5, Move towards the next irradiation space. At this time, the portion of the irradiation space S that is 10 mm or more away from the quartz protective tube 6 is hardly irradiated with ultraviolet rays with a wavelength of 185 nm, which has the shortest wavelength and the highest oxidation ability, but the outer diameter of the seal member 13 and the cylinder 2 is substantially the same as the inner diameter of the reflux plates 11a and 11b and the inner surface of the cylinder 2 is substantially free of clearance (gap), so that the water W to be treated is between the reflux plate 11b and the quartz protective tube 6. It must pass through the flow path. As a result, all of the water to be treated W is irradiated with ultraviolet rays having a wavelength of 185 nm, and hydroxy radicals are generated. By repeating this in four irradiation spaces S formed by five reflux plates, the TOC component can be sufficiently decomposed. In addition, since the UV irradiation from the low-pressure UV discharge lamp is sufficiently received, the hardly decomposable substance can be decomposed at a high level.

Next, a second embodiment of the ultraviolet oxidation processing apparatus of the present invention will be described in detail based on FIGS.
The ultraviolet oxidation treatment apparatus 1 according to this embodiment has the same configuration as that of the first embodiment described above except that the shape of the reflux plate is different. The reflux plate 21 includes an annular reflux plate body 22 and a seal member 13 disposed on the outer periphery of the reflux plate body 22. In FIG. 4, reference numeral 23 denotes an insertion hole for the pair of rods 7.

  Here, in the axial direction, the reflux plate main body portion 22 has a recess 24 formed at the outer peripheral end by a small diameter portion 22B at the middle portion and a large diameter portion 22A at both side surfaces, and the outer edge portion of the large diameter portion 22A is The structure is the same as that of the first embodiment described above except that it is long in the axial direction.

  The operation of the ultraviolet oxidation processing apparatus according to this embodiment having the reflux plate 21 as described above will be described. As shown in FIG. 7, the to-be-treated water W introduced from the treated water inlet passes through the flow path between the quartz protective tube 6 and the reflux plate 21a and flows into the irradiation space S. Since this irradiation space S is partitioned by the two reflux plates 21a and 21b, the water W to be treated stays here, and after securing a sufficient reaction time by the ultraviolet irradiation from the low-pressure ultraviolet discharge lamp 5, Move towards the next irradiation space. At this time, the portion of the irradiation space S that is 10 mm or more away from the quartz protective tube 6 is hardly irradiated with ultraviolet rays with a wavelength of 185 nm, which has the shortest wavelength and the highest oxidation ability, but the outer diameter of the seal member 13 and the cylinder 2 has substantially the same inner diameter and there is substantially no clearance (gap) between the outer peripheral edges of the reflux plates 21 a and 21 b and the inner surface of the cylinder 2, so that the water to be treated W is between the reflux plate 21 b and the quartz protective tube 6. It must pass through the flow path. As a result, all of the water to be treated W is subjected to sufficient ultraviolet oxidation, and hydroxy radicals are generated. By repeating this in four irradiation spaces S formed by five reflux plates, the TOC component can be sufficiently decomposed. In addition, since it is sufficiently irradiated with the low-pressure ultraviolet discharge lamp, the hardly decomposable substance can be decomposed at a high level.

  Furthermore, a third embodiment of the ultraviolet oxidation processing apparatus of the present invention will be described in detail based on FIGS. The ultraviolet oxidation treatment apparatus 1 of the present embodiment has the same configuration as that of the first embodiment described above except that the shape of the reflux plate is different.

  In the figure, a reflux plate 31 includes a disc-shaped reflux plate main body 32 having an opening having a diameter of about 10 mm or less, particularly 3 to 10 mm apart from the quartz protective tube 6 at the center, and the reflux plate. The seal member 33 is fixed to the outer periphery of the main body 32. In FIG. 8, reference numeral 34 denotes an insertion hole for the pair of rods 7. As described above, when the seal member 33 is configured not to be deteriorated by ultraviolet irradiation, such a configuration can be adopted.

  As mentioned above, although embodiment of this invention has been described with reference to an accompanying drawing, a sealing member is not limited to a ring-shaped thing, For example, as shown in FIG. It is good also as the sealing member 13A which wound resin or elastomer in the shape of a coil. Further, the ultraviolet oxidation treatment apparatus is not limited to the one shown in FIGS. 12 and 13 and can be applied as a reflux plate in various ultraviolet oxidation treatment apparatuses.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to each following Example at all.

[Preparation of test UV oxidation system]
Using the ultraviolet oxidation treatment apparatus 1 having the structure shown in FIG. 12, a pure water production apparatus shown in FIG. 11 was prepared. This pure water production apparatus includes an ultraviolet (UV) oxidizer 41 and an ion exchange resin column 42. The ultrapure water in which TOC is added from a TOC tank 43 by a chemical injection pump 44 is added to the ultraviolet (UV) oxidizer 41. Processing is performed by supplying water, and the TOC meter 45 measures the TOC concentration of the feed water of the ultraviolet (UV) oxidizer 41 and the TOC concentration of the treated water that has passed through the ion exchange resin column 42, respectively. .

In addition, in each Example and Comparative Example described later, the following was used as a common apparatus.
Low pressure ultraviolet discharge lamp: Low pressure mercury lamp AZ-26 (manufactured by Nippon Photoscience)
Ballast for discharge lamp: Electronic ballast FM-10Kd (manufactured by Nippon Photoscience)
Ion exchange resin column: “KR-UC1” 2 L and “KR-UA1” 3 L (both manufactured by Kurita Kogyo Co., Ltd.) are used in a mixed bed. TOC source: Special grade 2-propanol and special grade urea (both manufactured by Kanto Chemical Co., Inc.) Each diluted with ultrapure water TOC meter: SieversPPT (manufactured by Sievers)
Treated water flow rate during evaluation test: 7.5 L / min

[Example 1 and Comparative Examples 1 and 2]
Using a UV oxidizer 41 with a cylinder diameter of 50 mmφ and a reflux plate 11 (A type) shown in FIGS. 1 and 2, 2-propanol is added as a TOC source at a concentration of about 10 μg / L for processing. It was. Table 1 shows the measurement results of the TOC concentration of the feed water and treated water. The reflux plate 11 used was one in which the reflux plate body 12 was made of stainless steel and the seal member 13 was made of FEP (fluorine resin). The distance between the reflux plate 11 and the quartz protective tube was about 5 mm.

  In addition, the same treatment is performed for the case where the reflux plate is not used for comparison (Comparative Example 1) and the case where the conventional reflux plate 11 (without the seal member 13) is used (Comparative Example 2). The TOC concentration of feed water and treated water was measured. The results are shown in Table 1.

[Example 2 and Comparative Examples 3 and 4]
2-Propanol as a TOC source in the same manner as in Example 1 except that a UV oxidation apparatus 41 having a cylinder diameter of 80 mmφ and a reflux plate 11 (A type) shown in FIGS. Was added at a concentration of about 10 μg / L. Table 1 shows the measurement results of the TOC concentration of the feed water and treated water.

  Further, the same treatment is performed for the case where the reflux plate is not used for comparison (Comparative Example 3) and the case where the conventional reflux plate 11 (without the seal member 13) is used (Comparative Example 4). The TOC concentration of feed water and treated water was measured. The results are shown in Table 1.

Example 3
2-Propanol as the TOC source in the same manner as in Example 1 except that the UV oxidation apparatus 41 having a cylinder diameter of 80 mmφ and the reflux plate 21 (B type) shown in FIGS. Was added at a concentration of about 10 μg / L. Table 1 shows the measurement results of the TOC concentration of the feed water and treated water. In addition, the reflux plate 21 used the reflux plate body 22 made of stainless steel and the seal member 13 having a polyethylene resin molded body subjected to a titanium thin film treatment.

  As apparent from Table 1, in Examples 1 to 3 and Comparative Examples 1 to 4 using 2-propanol as the TOC source, Examples 1 to 3 had a TOC concentration of treated water of 0.5 μg / L or less. On the other hand, Comparative Examples 1 and 3 in which no reflux plate was used exceeded 1.0 μg / L, and Comparative Examples 2 and 4 using a conventional reflux plate exceeded 0.5 μg / L. Met. From this result, according to the ultraviolet oxidation treatment apparatus of the present invention, it was proved that treated water having an extremely low TOC concentration can be obtained.

[Example 4 and Comparative Examples 5 and 6]
Using a UV oxidation device 41 having a cylinder diameter of 50 mmφ and a reflux plate 11 (A type) shown in FIGS. 1 and 2, urea was added as a TOC source at a concentration of about 5 μg / L. Table 2 shows the measurement results of the TOC concentration of the feed water and treated water.

  In addition, the same treatment was performed for the case where the reflux plate was not used for comparison (Comparative Example 5) and the case where the conventional reflux plate 11 (without the seal member 13) was used (Comparative Example 6). The TOC concentration of feed water and treated water was measured. The results are shown in Table 2.

[Example 5 and Comparative Examples 7 and 8]
In the same manner as in Example 4 except that the UV oxidation apparatus 41 having a cylinder diameter of 80 mmφ and the reflux plate 11 (A type) shown in FIGS. The feed water added at a concentration of 5 μg / L was treated. Table 2 shows the measurement results of the TOC concentration of the feed water and treated water.

  Further, the same treatment is performed for the case where the reflux plate is not used for comparison (Comparative Example 7) and the case where the conventional reflux plate 11 (without the seal member 13) is used (Comparative Example 8). The TOC concentration of feed water and treated water was measured. The results are shown in Table 2.

Example 6
In the same manner as in Example 4 except that a UV oxidation apparatus 41 having a cylinder diameter of 80 mmφ and a reflux plate 21 (B type) shown in FIGS. The feed water added at a concentration of 5 μg / L was treated. Table 2 shows the measurement results of the TOC concentration of the feed water and treated water.

  As is clear from Table 2, in Examples 4 to 6 and Comparative Examples 5 to 8 using urea as the TOC source, Examples 4 to 6 had a urea concentration of treated water of about 30 μg / L or less, about half. In contrast, Comparative Examples 5 and 7 in which no reflux plate was used exceeded 4.0 μg / L, and Comparative Examples 6 and 8 using a conventional reflux plate were 3.0 μg / L. The removal rate was very low. From these results, it was confirmed that the ultraviolet oxidation treatment apparatus of the present invention can provide excellent effects even in the decomposition and removal of urea, which is a hardly decomposable substance.

DESCRIPTION OF SYMBOLS 1 ... Ultraviolet oxidation apparatus 2 ... Cylinder (outer cylinder body)
3 ... treated water inlet (water supply section)
4 ... treated water outlet (drainage)
5 ... Low-pressure ultraviolet discharge lamp 6 ... Quartz protective tube 11, 11a, 11b, 21, 21a, 21b, 31 ... Reflux plate 12, 22, 32 ... Reflux plate body 13, 13A, 33 ... Seal member 41 ... Ultraviolet (UV ) Oxidizer W ... treated water

Claims (6)

A tubular low-pressure ultraviolet discharge lamp is accommodated, and an outer cylinder in which water flows from one end to the other end around the low-pressure ultraviolet discharge lamp, and in the outer cylinder, in the outer circumferential direction of the low-pressure ultraviolet discharge lamp In the ultraviolet oxidation processing apparatus having a plurality of reflux plates provided apart from the low-pressure ultraviolet discharge lamp,
The ultraviolet ray oxidation processing apparatus, wherein the reflux plate has a seal portion that seals between the inner surface of the outer cylindrical body.   The ultraviolet oxidation processing apparatus according to claim 1, wherein the seal portion is not directly irradiated with ultraviolet rays from the low-pressure ultraviolet discharge lamp.   The ultraviolet oxidation treatment apparatus according to claim 1, wherein the reflux plate has an annular shape.   4. The ultraviolet oxidation processing apparatus according to claim 3, wherein the reflux plate includes an annular reflux plate main body portion and a seal portion disposed on an outer periphery of the reflux plate main body portion.   5. The ultraviolet oxidation treatment apparatus according to claim 1, wherein the seal portion is made of a material resistant to ultraviolet rays irradiated from the low-pressure ultraviolet discharge lamp.   An ultraviolet oxidation treatment method of water, wherein the ultraviolet oxidation treatment of water is performed using the ultraviolet oxidation treatment apparatus according to any one of claims 1 to 5.

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