JP2017196558A - Decomposing apparatus of organic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decomposing apparatus of an organic material that is equipped with an ultraviolet lamp and capable of efficiently decomposing an organic material in water of a small flow amount.SOLUTION: A decomposing apparatus 1 of an organic material includes a raw water tank 2 for storing water W to be treated containing an organic material, a gas permeable membrane module 3 of which one end of the liquid phase chamber 3A is connected to the raw water tank 2 via a circulation pump 4, an ultraviolet lamp 5 connected to the other end of the liquid phase chamber 3A of the gas permeable membrane module 3, an exhaust passage 6A for discharging the water W1 treated by the ultraviolet lamp 5, and a circulation line 6B branching from the exhaust passage 6A. The raw water tank 2 is equipped with a TOC sensor 7 to measure the TOC concentration of the treated water W1. Air as an oxygen-containing gas is introduced to the gas phase chamber 3B side of the gas permeable membrane module 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an organic substance decomposition apparatus for reducing the organic substance concentration of organic substance-containing water, and more particularly to an organic substance decomposition apparatus provided with an ultraviolet irradiation device capable of efficiently decomposing organic substances in organic substance-containing water.

  Conventionally, there is a method of irradiating ultraviolet rays as means for decomposing organic substances in water, such as removing TOC from waste water containing TOC (total organic carbon) in a semiconductor or liquid crystal factory. Decomposition of organic matter by ultraviolet irradiation is disadvantageous in terms of running cost, which consumes more power than other organic matter removal / decomposition treatments. It has the merit that it is very easy and requires few incidental facilities.

It is understood that the decomposition reaction of organic substances by such ultraviolet irradiation is due to the generation of hydroxy radicals by decomposition of water and the strong oxidizing power of the hydroxy radicals. Further, in the decomposition process of organic matter, although depending on the target organic matter, carbon dioxide (CO ₂ ) is produced as a final decomposition product via an intermediate such as an organic acid.

  In this organic matter decomposition method by ultraviolet irradiation, various proposals have been made to use an oxidizing agent in combination with ultraviolet irradiation in order to efficiently treat a large amount of waste water.

  For example, in Patent Document 1, when oxidizing and decomposing and removing organic matter contained in wastewater such as industrial wastewater and municipal sewage, wastewater is discharged into a reaction tank equipped with a hydrogen peroxide solution addition device, an ultraviolet lamp, and an aeration device. An apparatus is disclosed in which an oxygen treatment is performed by adding a certain amount of hydrogen peroxide as an oxidant and then diffusing ozonized gas from an air diffuser while irradiating ultraviolet rays.

  Further, in Patent Document 2, an oxidant is added to organic matter-containing water under ultraviolet irradiation, and the organic matter contained in the treated water is subjected to the TOC value in the whole treated water when oxidative decomposition treatment is performed. A method for treating organic substance-containing water is disclosed in which the amount of oxidant mixed in water is controlled within a range of 1 to 5 equivalents over time.

  In Patent Document 3, it is difficult to circulate a part of treated water to an ultraviolet irradiation process in a method of physicochemical treatment of wastewater containing hardly decomposable organic matter in an oxidative decomposition tank using ultraviolet rays and an oxidizing agent in combination. Disclosed is a method for treating difficult-to-decompose organic matter-containing wastewater that is irradiated with ultraviolet light after being diluted with decomposed bioorganic matter-containing wastewater.

  Patent Document 4 discloses a water treatment apparatus for decomposing an organic substance contained in water to be treated, which comprises a contact means for bringing air or oxygen into contact with the treated water at a pressure greater than atmospheric pressure, and a photocatalyst. Water containing organic matter comprising a decomposition means for decomposing the organic matter by bringing the photocatalyst and the water to be treated into contact with each other at a pressure higher than atmospheric pressure while irradiating the water to be treated in contact with air or oxygen with UV light A processing device is disclosed.

  Furthermore, a method is also widely known in which the amount of ultraviolet irradiation is limited to such an extent that an organic substance decomposes into an ionic intermediate such as an organic acid, and this ionic intermediate is treated in combination with an ion exchange treatment or the like. According to this method, the cost for the ultraviolet irradiation device can be kept to a minimum, and as a result, the operation cost of the water treatment facility can be minimized.

JP 60-28883 A JP-A-62-262792 JP-A-10-52693 JP 2011-245422 A

  As described in Patent Documents 1 to 3, the method of using ultraviolet irradiation and an oxidizing agent in combination can be processed with a simple configuration comprising an oxidizing agent addition facility and an ultraviolet irradiation device, and is suitable for a small flow rate. This is a useful method as a processing method. When chemicals such as peroxides such as hydrogen peroxide are used as oxidizers, there is a concern with dangerous work such as supplementation of peroxides that requires care, but when air is used as the oxidizer. Has the advantage of not having this concern.

  However, in the method using these oxidizing agents in combination, carbon dioxide is generated when the organic matter is decomposed. Therefore, when the concentration of organic matter in the water to be treated is high, carbon dioxide as a radical scavenger accumulates in the system. Therefore, there is a problem that the decomposition efficiency of the organic matter may be significantly reduced.

  In the treatment method described in Patent Document 4 in which air or oxygen is brought into contact with water to be treated at a pressure greater than atmospheric pressure, ultraviolet irradiation, and further a photocatalyst is used in combination, air or oxygen is used in an aeration sphere. Since carbon dioxide is extruded and discharged together with the supply of oxygen, the effect of avoiding adverse effects due to the accumulation of carbon dioxide can be expected. However, when air or oxygen is supplied using an aeration bulb, there is a problem that a sufficient oxygen supply effect and carbon dioxide discharge effect cannot be obtained.

  Furthermore, in the method in which the ultraviolet ray irradiation amount is limited to the extent that the organic substance decomposes into an ionic intermediate such as an organic acid, and the treatment is performed in combination with the ion exchange treatment, an auxiliary device such as an ion exchange device is required. In addition, when the concentration of organic matter to be decomposed (the amount of organic matter) is high, the load on the ion exchange equipment increases, so regeneration equipment for the ion exchange equipment is also required, and the treatment system must be complicated, resulting in a large water volume scale. However, there is a problem that it is unsuitable as a processing method for a small flow rate scale, which requires that ancillary facilities are limited and maintenance is easy.

Here, in order to decompose the organic substance into carbon dioxide (CO ₂ ), oxygen (O) 2 mol (O ₂ ) is required for 1 mol of carbon (c), and a part of oxygen (O) is an organic substance. Although a trace amount is supplied from a product generated in the decomposition process or water (H ₂ O), it is necessary to supply at least an equivalent amount from the outside. For example, decomposition of TOC = 100 mg / L (asC) requires about 270 mg / L (asO ₂ ) of oxygen. The saturated dissolved oxygen concentration of water at room temperature and normal pressure is about 6 mg / L (asO ₂ ) when the contact gas is air, and about 40 mg / L (asO ₂ ) even when the contact gas is oxygen. Therefore, since 270 mg / L (asO ₂ ) oxygen cannot be supplied to the organic substance-containing water as it is, some device is required.

Therefore, it is conceivable to supply oxygen in a gas-liquid mixed phase flow, not as dissolved oxygen, to supply that amount of oxygen even at room temperature and normal pressure, but the oxygen supplied as bubbles is an ultraviolet irradiation device. It is very difficult to realize a system that dissolves appropriately and contributes to the decomposition of organic substances. Furthermore, in order to dissolve 270 mg / L (asO ₂ ) of oxygen in advance, it is necessary to use a pressure condition that is 6 to 7 times the atmospheric pressure. This is also not realistic.

  That is, conventionally, there has been no organic matter decomposing apparatus equipped with an ultraviolet irradiation device for a small flow scale capable of efficiently decomposing organic substances in organic substance-containing water.

  This invention is made | formed in view of this subject, and it aims at providing the organic substance decomposition | disassembly apparatus provided with the ultraviolet irradiation apparatus for small flow scales which can decompose | disassemble the organic substance in organic substance containing water efficiently.

  In view of the above-described object, the present invention is an organic matter decomposing apparatus including an ultraviolet irradiation device that treats organic matter-containing water as water to be treated, and the organic matter-containing water provided in the front stage of the ultraviolet irradiation device passes through the organic substance decomposition device. A gas permeable membrane module having a liquid phase chamber and a gas phase chamber through which an oxygen-containing gas partitioned from the liquid phase chamber and the gas permeable membrane passes, and a part or all of the treated water treated by the ultraviolet irradiation device An organic matter decomposing apparatus including a circulating mechanism for circulation is provided (Invention 1).

  According to this invention (Invention 1), the organic substance-containing water first passes through the liquid phase chamber of the gas permeable membrane module, but since this gas permeable membrane module has a very large contact area with the organic substance-containing water, By circulating a gas containing oxygen on the chamber side, oxygen necessary for the decomposition of the organic substance can be efficiently supplied to the organic substance-containing water through the gas permeable membrane, while being an inhibitory ingredient for the decomposition of the organic substance. If carbon dioxide is excessively contained in the organic substance-containing water, the carbon dioxide flows from the liquid phase chamber side to the gas phase chamber side and can be discharged. Subsequently, the organic matter can be effectively decomposed by treating the treated water supplied with oxygen in this way with an ultraviolet irradiation device. And when the organic matter concentration in the organic matter-containing water is high, the organic matter can be supplied while appropriately supplying oxygen to the organic matter-containing water by treating the whole or a part of the treated water of the ultraviolet irradiation device by circulation with a circulation mechanism. It can be reduced to a desired concentration.

  In the said invention (invention 1), it is preferable to provide the TOC sensor which measures the organic substance density | concentration of the treated water processed with the said ultraviolet irradiation device (invention 2).

  In this invention (Invention 2), by measuring the organic substance concentration of the treated water treated with the ultraviolet irradiation device with the TOC sensor, the circulation by the circulation mechanism is stopped when the organic substance concentration becomes less than the desired value, What is necessary is just to discharge | emit water to the exterior from an organic matter decomposition device.

  According to the organic matter decomposing apparatus of the present invention, oxygen necessary for organic matter decomposition can be efficiently supplied to the organic matter-containing water, and after exhausting excess carbon dioxide that becomes an inhibitory component of organic matter decomposition, ultraviolet irradiation is performed. Since the treatment is performed by the apparatus, the organic matter in the organic matter-containing water can be effectively decomposed. When the organic matter concentration in the organic matter-containing water is high, the organic matter is reduced to a desired concentration while appropriately supplying oxygen by treating the whole or part of the treated water of the ultraviolet irradiation device while circulating it. be able to.

It is a flowchart which shows the organic substance decomposition | disassembly apparatus by one Embodiment of this invention.

  Hereinafter, an embodiment of the organic matter decomposition apparatus of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an organic matter decomposing apparatus according to this embodiment. In FIG. 1, the organic substance decomposing apparatus 1 includes a raw water tank 2 for storing treated water W, which is organic substance-containing water, and this raw water tank 2 and a circulation pump 4. The gas permeable membrane module 3 connected on one side of the liquid phase chamber 3A, the ultraviolet irradiation device 5 connected to the other side of the liquid phase chamber 3A of the gas permeable membrane module 3, and the ultraviolet irradiation device 5 It has a discharge path 6A that discharges the treated water W1, and a circulation path 6B that is a circulation mechanism branched from the discharge path 6A. The raw water tank 2 is provided with a TOC sensor 7 that measures the TOC concentration of the water to be treated W. The gas permeable membrane module 3 is configured such that air (air) as an oxygen-containing gas flows through the gas phase chamber 3B side. In addition, the codes | symbols 8 and 9 in FIG. 1 are the switching valves provided in the discharge path 6A and the circulation path 6B, respectively.

  In the organic matter decomposing apparatus 1 as described above, the gas permeable membrane constituting the gas permeable membrane module 3 is a membrane that does not allow liquid such as water to pass but allows gas (gas) to pass. In order to efficiently supply oxygen to the water to be treated W and efficiently discharge carbon dioxide generated with the decomposition of organic matter, it is preferable to have a gas-liquid contact surface that is as wide as possible. A degassing membrane or a dissolving membrane module in which the gas permeable membrane is filled with high density can be suitably used.

  Although there is no restriction | limiting in particular as the ultraviolet irradiation device 5, For example, a low pressure mercury lamp, a high pressure mercury lamp, a hydrogen discharge tube, a xenon discharge tube etc. can be used. As this ultraviolet irradiation device 5, a device that irradiates ultraviolet rays having a wavelength of 200 nm or less, particularly around 185 nm can be suitably used.

  Next, the operation of the organic matter decomposition apparatus 1 according to this embodiment having the above-described configuration will be described. First, the circulation pump 4 is activated to supply the water to be treated W from the raw water tank 2 to one side of the liquid phase chamber 3 </ b> A of the gas permeable membrane module 3. On the other hand, a certain amount of air (Air) is supplied to the gas phase chamber 3B of the gas permeable membrane module 3 by a sweep method. At this time, by setting the pressure in the gas phase chamber 3B to be slightly higher than that in the liquid phase chamber 3A, oxygen gas in the air passes through the gas permeable membrane and is supplied to the water to be treated W in the liquid phase chamber 3A. On the other hand, when an excessive amount of carbon dioxide is dissolved in the water to be treated W, it is discharged into the gas phase chamber 3B.

The treated water W supplied with oxygen is discharged from the other side of the liquid phase chamber 3A, supplied to the ultraviolet irradiation device 5, and irradiated with ultraviolet rays to oxidatively decompose organic substances in the treated water W. The amount of ultraviolet irradiation by the ultraviolet irradiation device 5 is preferably 0.05 kwh / m ³ or more, particularly 0.1 kwh / m ³ with respect to the water to be treated W flowing into the ultraviolet oxidation device 5. If the amount of ultraviolet irradiation is less than 0.05 kwh / m ³ , the generation of hydroxy radicals is not sufficient, and the time required to reduce the TOC to the desired removal rate becomes too long. However, even if the amount of ultraviolet irradiation is excessively large, the TOC removal rate reaches its peak, and therefore the amount of ultraviolet irradiation should normally be in the range of 0.05 to 2 kwh / m ³ .

  At this time, by closing the switching valve 8 and opening the switching valve 9, the treated water W1 in which the organic matter has been decomposed is returned to the raw water tank 2 from the circulation path 6B via the discharge path 6A. The above process is repeated ((1) in FIG. 1). At this time, the organic substance concentration of the water W to be treated in the raw water tank 2 is measured by the TOC sensor 7, and when the TOC value becomes less than a desired value, the switching valve 8 is opened while the switching valve 9 is closed. As a result, the treated water W1 can be discharged from the discharge path 6A and forwarded to the next treatment step such as a pure water production apparatus, or can be used for other general purposes (in FIG. 1). (2)). Further, the treated water W1 may be sent to the next treatment step together with the raw water tank 2 without being discharged from the discharge path 6A. By treating the water W to be circulated in this way, even if the organic matter concentration of the water W to be treated is high, the gas permeable membrane module 3 can be treated while appropriately supplying oxygen at normal temperature and pressure. It is possible to easily operate the organic matter decomposing apparatus.

  In the treatment as described above, an oxidizing agent may be added to the treated water W as necessary. In this case, an oxidizer addition facility is attached, but in the present embodiment, the gas permeable membrane module 3 efficiently supplies oxygen to the treated water W and discharges carbon dioxide. Therefore, since the addition amount of the oxidizing agent is small, the addition equipment can be small. Although there is no restriction | limiting in particular in this oxidizing agent, Peroxides, such as hydrogen peroxide and a persulfuric acid compound, can be used suitably.

  As mentioned above, although this invention has been demonstrated based on the said embodiment, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible. For example, in the present embodiment, the entire amount of the treated water W1 is circulated, but a part may be circulated by controlling the opening / closing timing of the switching valves 8 and 9. Further, the oxygen-containing gas is not air but oxygen may be supplied by generating oxygen using PSA or the like.

  The following specific examples further illustrate the present invention.

[Example 1]
Simulated waste water (treated water) W containing TOC≈100 mg / L containing alcohols and organic acids was prepared. In the organic matter decomposition apparatus 1 shown in FIG. 1, G453 (manufactured by Rixell) is used as the gas permeable membrane module 3, MDG-H2A100 (manufactured by Iwaki) is used as the circulation pump 4, and KUS-1 / 2N-SP is used as the ultraviolet irradiation apparatus 5. (Nippon Photo Science Co., Ltd.) was used.

In the apparatus configured as described above, 2 L of simulated waste water W is stored in the raw water tank 2, and this simulated waste water W is continuously circulated at about 2 L / min using the circulation pump 4, and the gas permeable membrane module 3 is provided. Continuously supplied air at normal temperature at 0.5 NL / min. When the dissolved oxygen concentration of the simulated waste water W in the raw water tank 2 at this time was measured over time, the dissolved oxygen concentration was 4 to 6 mg / L (asO ₂ ). And the TOC of the simulated waste water W fell to 3 mg / L or less after about 15 hours. The results are shown in Table 1 together with the processing conditions.

[Comparative Example 1]
In Example 1, the organic substance decomposition apparatus was configured without using the gas permeable membrane module 3. In this apparatus, treatment was performed in the same manner as in Example 1 except that oxygen aeration was performed at 0.5 NL / min using an air balloon in the raw water tank 2. When the dissolved oxygen concentration of the simulated waste water W in the raw water tank 2 at this time was measured over time, the dissolved oxygen concentration was 15 to 20 mg / L (asO ₂ ). And the TOC of the simulated waste water W was reduced to 3 mg / L or less after about 18 hours. The results are shown in Table 1 together with the processing conditions.

[Comparative Example 2]
In Example 1, the organic substance decomposition apparatus was configured without using the gas permeable membrane module 3. In this apparatus, treatment was performed in the same manner as in Example 1 except that air was aerated in the raw water tank 2 at 2 NL / min. At this time, when the dissolved oxygen concentration of the simulated waste water W in the raw water tank 2 was measured over time, the dissolved oxygen concentration was 0 to 5 mg / L (asO ₂ ). And the TOC of the simulated waste water W was reduced to 3 mg / L or less after about 16 hours. The results are shown in Table 1 together with the processing conditions.

  As is apparent from Table 1, the organic matter decomposition apparatus of Example 1 that was circulated using the gas permeable membrane module and the ultraviolet irradiation device was able to efficiently decompose the organic matter. On the other hand, Comparative Example 1 in which the raw water tank 2 was aerated with oxygen had the highest dissolved oxygen concentration, so it seemed that the organic matter decomposition efficiency was good, but it took the longest time to reach TOC 3 mg / L or less. This is presumably because the discharge of carbon dioxide, which is a radical scavenger, stagnated due to a small aeration flow rate, and the decomposition efficiency of organic substances was lowered. On the other hand, in Comparative Example 2 in which the aeration amount of air was increased in order to ensure the dissolved oxygen concentration, the discharge of carbon dioxide was promoted, and it is considered that the decomposition efficiency of organic matter was improved as compared with Comparative Example 1.

DESCRIPTION OF SYMBOLS 1 Organic substance decomposition apparatus 2 Raw water tank 3 Gas permeable membrane module 3A Liquid phase chamber 3B Gas phase chamber 4 Circulation pump 5 Ultraviolet irradiation device 6A Discharge path 6B Circulation path (circulation mechanism)
7 TOC sensor W treated water W1 treated water

Claims (2)

An organic matter decomposition apparatus equipped with an ultraviolet irradiation device for treating organic substance-containing water as treated water,
A gas permeable membrane having a liquid phase chamber through which the organic substance-containing water passes, and a gas phase chamber through which the oxygen-containing gas partitioned from the liquid phase chamber and the gas permeable membrane pass, are provided in the preceding stage of the ultraviolet irradiation device Module,
An organic matter decomposition apparatus comprising: a circulation mechanism that circulates part or all of the treated water treated by the ultraviolet irradiation device.   The organic matter decomposition | disassembly apparatus of Claim 1 provided with the TOC sensor which measures the organic substance density | concentration of the treated water processed with the said ultraviolet irradiation device.

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