JP2008175759A - Device and method for treating detergent liquid waste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for treating detergent liquid waste which make it possible to efficiently decompose organic matter included in the detergent liquid waste by adding a filter aid to it beforehand, pouring ozone gas and mixing it with the detergent liquid waste. <P>SOLUTION: The device for treating the detergent liquid waste has a collection tank 3 for storing a detergent liquid waste 2 discharged from a nuclear power plant, a filter aid tank 13 for adding the filter aid beforehand to the detergent liquid waste 2 introduced from the collection tank 3, an ozone generator 15 for generating the ozone gas 8, one or more ozone reaction tanks 4 to which the detergent liquid waste 2 doped with the filter aid and the ozone gas 8 are introduced, diffusing plates or diffusing cylinders 16 which are placed in the ozone reaction tanks 4 and are a gas-liquid mixing means for mixing the detergent liquid waste 2 and the ozone gas 8 to accelerate the oxidative destruction of the organic matter included in the detergent liquid waste 2, a filter 5 for removing solid contents in the detergent liquid waste 2 destroyed oxidatively and a waste ozone degradation tower 7 filled with an inactivating catalyst for degrading the ozone gas 8 which is not spent for the oxidative destruction in the ozone reaction tanks 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laundry facility of a nuclear power plant, and relates to a laundry waste liquid treatment apparatus and method for the purpose of efficiently using ozone gas used in a laundry waste liquid treatment apparatus attached to the facility.

  In a nuclear power plant, work clothes and the like worn in a management area are washed in a laundry facility. After measuring the radionuclide concentration of the washing waste liquid and confirming that the concentration is sufficiently low, it is released to the environment. The nature of this washing waste liquid depends on the washing method, but washing by washing with a washing detergent is generally used as is done at home. When the laundry waste liquid is discharged to the environment, in addition to the above radionuclide concentration, pH, suspended solid content (hereinafter referred to as SS content) concentration, chemical oxygen demand (hereinafter referred to as COD) are emission standard values. Must be: It is necessary to keep the pH within a certain range.

  For this purpose, a washing facility is permanently installed in the nuclear power plant, and includes a washing machine for washing work clothes and a washing waste liquid treatment apparatus. The laundry waste liquid treatment apparatus is installed mainly for the purpose of removing radionuclides, SS components and COD components present in the waste liquid. Most of the radionuclides present in the laundry waste liquid are accompanied by solid content called clad, and can be removed by filtering with a filter. Similarly, the SS component can be removed by filtration in the same manner as the radionuclide component. The COD component is mainly a surfactant added as a detergent. In addition, oils and fats attached to work clothes and sebum components from the human body are included.

In order to remove these COD components, various treatment methods and apparatuses have been conventionally developed. Since the COD component is an organic substance, a method of removing it by adsorbing on activated carbon is known (for example, see Patent Document 1). In addition, a method of decomposing a COD component by adding an oxidizing agent such as hydrogen peroxide is known (for example, see Patent Document 2). In addition, a method of evaporating and washing laundry waste liquid itself by using a low foaming detergent has been developed. Recently, many decomposition processes of COD components using the oxidizing power of ozone gas have been proposed (see, for example, Non-Patent Document 1). In this waste liquid treatment method using ozone gas, a method in which a catalyst is used in combination has also been proposed in order to increase the decomposition power of ozone dissolved in the laundry waste liquid (see, for example, Patent Document 3).
Japanese Patent Laid-Open No. 06-331792 Japanese Unexamined Patent Publication No. 07-027898 Japanese Patent Application Laid-Open No. 09-253672 Hidetoshi Sugimitsu, “Basics and Applications of Ozone”, Mitsutoshi Co., Ltd., 1996

  In order to increase the decomposing power of ozone dissolved in the laundry waste liquid, a method using a catalyst in combination has also been proposed as the above-described conventional treatment method for waste waste liquid using ozone gas. In other words, washing waste liquid is treated using ozone gas as an oxidizing agent and a powdered metal oxide having catalytic ability as a filter aid.

  However, the laundry waste liquid treatment apparatus using ozone gas has a problem that about 50% of the injected ozone gas is discarded without being used. For this reason, since it cannot decompose | disassemble even to the hard-to-filter solid content contained in the washing waste liquid which uses ozone gas as an oxidizing agent, filterability is not improved greatly after ozone treatment. For this reason, the load of the filter which removes the solid content contained in the waste liquid after ozone treatment was large, the backwash frequency increased, and there was a problem that the amount of waste liquid discharged increased.

  In addition, in the waste liquid treatment method using ozone gas as an oxidant, for example, a ceramic dust cylinder or a mixing pump used for gas-liquid mixing is used as an ozone injection method. Due to the large size, there is a problem that the bubble rises rapidly in the liquid and is exhausted without being effectively used as an oxidant.

  Furthermore, the waste ozone decomposition tower which is incidental equipment tends to be large, and there also existed a subject that operating cost rose.

  The present invention has been made to solve the above-described problem, and an object thereof is to provide a laundry waste liquid treatment apparatus and method that can efficiently perform oxidative decomposition of organic substances contained in laundry waste liquid by ozone gas. To do.

  In order to achieve the above object, in the laundry waste liquid treatment apparatus of the present invention, a filtration tank is preliminarily filtered into the collection tank storing the laundry waste liquid discharged from the washing facility of the nuclear power plant and the laundry waste liquid introduced from the collection tank. A filter aid tank for adding an agent, an ozone generator for generating ozone gas, at least one ozone reaction tank into which the washing waste liquid to which the filter aid is added and the ozone gas are introduced, and the inside of the ozone reaction tank Alternatively, gas-liquid mixing means that is provided outside and mixes the laundry waste liquid and the ozone gas to promote oxidative decomposition of the organic matter contained in the laundry waste liquid, and removes the solid content in the oxidatively decomposed laundry waste liquid. A filter, a sample tank in which the washing waste liquid from which the solid content has been removed is temporarily stored and discharged before being discharged into the environment, and the ozone reaction tank. There deactivating catalyst for decomposing has not been used for oxidative decomposition ozone gas is characterized in that it has a, a waste ozone decomposing column being filled.

  In order to achieve the above object, in the laundry waste liquid treatment method of the present invention, the step of storing the waste laundry liquid discharged from the washing facility of the nuclear power plant in the collection tank, and the waste laundry liquid introduced from the collection tank A step of adding a filter aid in advance to the washing waste liquid to which the filter aid has been added and the ozone gas are introduced into at least one ozone reaction tank, and the laundry waste liquid and the ozone gas are mixed to be contained in the laundry waste liquid. Promoting the oxidative decomposition of the organic matter to be removed, the step of removing the solid content in the waste solution of this oxidative decomposition by the filter, and the quality of the water before the waste waste solution from which the solid content has been removed is temporarily stored and released to the environment. A step in which a check is performed, and a step in which ozone gas that has not been used for oxidative decomposition in the ozone reaction tank is decomposed using a deutilized catalyst. When, is characterized in that it has a.

  According to the laundry waste liquid treatment apparatus and the method of the present invention, a filter aid is added to the laundry waste liquid in advance, ozone gas is injected, the laundry waste liquid and the ozone gas are mixed, and the organic matter contained in the laundry waste liquid is efficiently obtained. The decomposition can be achieved, and the reaction time can be reduced to reduce the washing waste liquid treatment time.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a washing waste liquid treatment apparatus and method according to the present invention will be described with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

  FIG. 1 is a configuration diagram illustrating a laundry waste liquid treatment apparatus according to a first embodiment of the present invention, and FIG. 2 is a configuration diagram illustrating a basic configuration of the laundry waste liquid treatment apparatus.

  First, the basic configuration of the laundry waste liquid treatment apparatus will be described with reference to FIG. The washing waste liquid treatment apparatus using ozone gas includes a collection tank 3 in which washing waste liquid 2 discharged from the washing machine 1 is stored. The stored washing waste liquid 2 is introduced into the ozone reaction tank 4 through the pump 10. In the ozone reaction tank 4, the laundry waste liquid 2 reacts with the introduced ozone gas 8 for a predetermined time, and the organic matter in the laundry waste liquid 2 is oxidized and decomposed into a solid content. The oxidatively decomposed laundry waste liquid 2 is introduced into the filter 5 via the pump 11 and the solid content produced by oxidative decomposition of the organic matter is removed together with the solid content originally contained in the laundry waste liquid 2. In addition, the treatment liquid 30 which is the waste solution of oxidative decomposition is temporarily stored in the sample tank 6. In this sample tank 6, a water quality check is performed. The treatment liquid 30 subjected to this water quality check is discharged to the environment via the pump 12. Further, the exhausted ozone gas 9 discharged in the air without being dissolved in the ozone reaction tank 4 is led to the waste ozone decomposition tower 7. The waste ozone decomposing tower 7 is filled with an ozone deutilizing catalyst having a metal base or the like supported on the surface of a ceramic substrate.

  In the laundry waste liquid treatment apparatus configured as described above, the laundry waste liquid 2 reacts with the ozone gas 8 for a predetermined time, and the organic matter in the laundry waste liquid 2 is oxidized and decomposed into a solid content. The processing liquid that has finished the reaction is separated into solid and liquid by passing through the filter 5, and the solution is led to the sample tank 6. Exhaust ozone gas 9 that is discharged into the atmosphere without being dissolved in the ozone reaction tank 4 is led to a waste ozone decomposition tower 7. In the waste ozone decomposing tower 7, the exhausted ozone gas 9 that has not been used for oxidative decomposition is decomposed using an ozone deutilizing catalyst in which a metal oxide or the like is supported on the surface of a ceramic substrate. This ozone depletion catalyst deteriorates due to heat generated during ozone decomposition and becomes waste.

  Next, the washing waste liquid treatment apparatus according to the first embodiment of the present invention will be described with reference to FIG. This figure is provided by adding a filter aid tank 13 to the basic structure of FIG. 2, and the same or similar parts as in FIG.

  As shown in FIG. 1, in order to improve the filterability of the washing waste liquid 2 stored in the collection tank 3, a filter aid tank 13 is installed to add a filter aid in advance. The filter aid used here is preferably a metal oxide powder and particles of 0.5 μm to 50 μm. In the case of particles smaller than 0.5 μm, the solid content in the washing waste liquid 2 is likely to pass through the filter 5 without being filtered, and in the case of particles exceeding 50 μm, it is contained in the washing waste liquid 2 after the ozone treatment. This is because the load on the filter 5 for removing the solid content increases and the frequency of backwashing increases. For this reason, the metal oxide powder is practically preferably in the range of 0.5 μm to 50 μm.

  Moreover, as a kind of metal oxide, an iron-type, manganese-type, or copper-type single or compound may be used, and the addition amount is injected in a range of 1 ppm to 1000 ppm. If the addition amount is less than 1 ppm, the possibility that the solid content in the washing waste liquid 2 will pass through the filter 5 without filtering is excessive, and if the addition amount exceeds 1000 ppm, it is contained in the washing waste liquid 2 after the ozone treatment. This is because the load on the filter 5 for removing the solid content increases and the frequency of backwashing increases. For this reason, it is preferable to inject | pour so that the addition amount of a metal oxide may become the range of 1 ppm-1000 ppm practically.

  In the laundry waste liquid treatment apparatus configured as described above, the laundry waste liquid 2 stored in the collection tank 3 is heated by the heater 14 and then supplied to at least one ozone reaction tank 4 to be decomposed. Here, the ozone reaction tanks 4a, 4b, 4c from the first tank to the third tank are illustrated. The liquid temperature in the ozone reaction tanks 4a, 4b, and 4c is maintained at 50 ° C. to 80 ° C., and the washing waste liquid 2 continuously stays in the ozone reaction tanks 4a, 4b, and 4c until a predetermined COD concentration is reached. The ozone-treated laundry waste liquid 2 is led to the ozone-treated water receiving tank 17. The washing waste liquid 2 subjected to the ozone treatment is supplied to the filter 5 through the pump 11, and the solid content generated by the oxidative decomposition of the organic matter together with the solid content originally contained in the washing waste liquid 2 is separated. Finally, the quality of the processing liquid 30 separated into solid and liquid via the filter 5 is checked in the sample tank 6. Further, the ozone gas 8 generated in the ozone generator 15 is introduced into a diffusion plate or a diffusion cylinder 16 which is a gas-liquid mixing means installed at the bottom of the ozone reaction tanks 4a, 4b, 4c. This diffuser plate or diffuser cylinder 16 has a plate-like structure or a cylindrical structure in which many pores are formed on the outer surface in order to release bubbles of the ozone gas 8 into the washing waste liquid 2, or from a porous material. Composed. The material of the diffuser plate or the diffuser cylinder 16 is selected from ceramics, glass, metal or plastic.

  According to the present embodiment, a filter aid is added in advance to the washing waste liquid, ozone gas is injected and the washing waste liquid and the ozone gas are mixed, and the organic matter contained in the washing waste liquid is efficiently decomposed. The reaction time can be reduced to reduce the washing waste liquid treatment time. In the conventional washing waste liquid treatment apparatus, about 50% of the injected ozone gas is discarded without being used, but according to the present embodiment, it is retained in the liquid by promoting the bubbling of the injected ozone. The time can be lengthened, and the utilization efficiency of ozone gas can be greatly increased.

  FIG. 3 is a configuration diagram showing a laundry waste liquid treatment apparatus according to the second embodiment of the present invention. In this figure, a mixing pump 18 is provided in place of the air diffuser plate (cylinder) 16 in the washing waste liquid treatment apparatus of FIG. 1, and the same or similar parts as in FIG. Description is omitted.

  As shown in this figure, the supply ozone gas 8 generated in the ozone generator 15 is supplied to the washing waste liquid 2 via a mixing pump 18 which is a gas-liquid mixing means installed outside the three ozone reaction tanks 4a, 4b and 4c. Injected into.

  According to this embodiment, by injecting ozone gas 8 through mixing pump 18 which is a bubble mixer, gas-liquid mixing of washing waste liquid 2 and ozone gas 8 is promoted, and the organic matter contained in washing waste liquid 2 is Efficient decomposition can be achieved and the reaction time can be reduced. That is, by promoting bubble mixing of the washing waste liquid 2 and the ozone gas 8, the gas utilization efficiency can be greatly increased.

  FIG. 4 is a block diagram showing a laundry waste liquid treatment apparatus according to the third embodiment of the present invention. This figure is provided with a fine bubble generator 19 in addition to the mixing pump 18 of the washing waste liquid treatment apparatus of FIG. 3, and the same or similar parts as in FIG. Is omitted.

  As shown in the figure, the ozone gas 8 generated in the ozone generator 15 is branched by a valve 20 and introduced from the first tank to the ozone reaction tanks 4a, 4b, 4c of the third tank. A fine bubble generator 19 is installed on the upstream side of each mixing pump 18. By supplying the ozone gas 8 to the ozone reaction tanks 4a, 4b, and 4c through the fine bubble generating device 19, gas-liquid mixing of the washing waste liquid 2 and the ozone gas 8 in the ozone reaction tanks 4a, 4b, and 4c is promoted. Is done.

  That is, the ozone gas 8 generated in the ozone generator 15 is branched by the valve 20 and introduced into the three ozone reaction tanks 4a, 4b, and 4c. A fine bubble generator 19 is installed on the upstream side of each mixing pump 18. By supplying the ozone gas 8 through the three microbubble generators 19, the gas-liquid mixing of the washing waste liquid 2 and the ozone gas 8 in the ozone reaction tank 4 is promoted.

  In the washing waste liquid treatment apparatus configured as described above, the gas bubbles stay in the liquid for a long time because the bubble diameter of the ozone gas 8 injected into the washing waste liquid is fine. For this reason, at the first stage, as indicated by the thick line A in FIG. 5, the valve 20 is operated to switch the ozone gas 8 to the ozone reaction tank 4a of the first tank. Since the bubble diameter of the ozone gas 8 is fine, the gas bubbles stay in the liquid for a long time. In the next stage, as indicated by a thick line B in FIG. 6, the valve 20 is operated to switch the ozone gas 8 to flow into the ozone reaction tank 4b of the second tank.

  According to the present embodiment, the valve 20 is operated so that the ozone gas 8 flows through the three ozone reaction tanks 4a, 4b, and 4c. In this way, by adjusting the ozone reaction tanks 4a, 4b, and 4c to adjust the ozone gas to flow smoothly, the dissolution of the ozone gas into the liquid is accelerated, and the organic gas decomposition efficiency is improved by the finer bubble of the ozone gas. It can be used and the reaction time can be reduced. Further, by reducing the bubbles of the injected ozone gas to increase the gas surface area, the residence time in the liquid can be extended, and the gas utilization efficiency can be greatly increased. Furthermore, by switching the injection point of such ozone gas, it is possible to supply ozone gas to the three ozone reaction tanks 4a, 4b, and 4c with one ozone generator 15, and to reduce the size of the ozone generator 15. Can also be achieved.

  FIG. 7 is a block diagram showing a laundry waste liquid treatment apparatus according to the fourth embodiment of the present invention. In this figure, a valve 22 is provided in addition to the fine bubble generating device 19 of the washing waste liquid treatment apparatus of FIG. 4, and the same or similar parts as in FIG. Omitted.

  As shown in the figure, the exhausted ozone gas 21 discharged from the ozone reaction tank 4 can be returned to the ozone reaction tank 4 other than the ozone reaction tank injecting ozone through the valve 22 and reused.

  In the laundry waste liquid treatment apparatus configured as described above, as shown by the thick line C in FIG. 8, when the ozone gas 8 is injected into the ozone reaction tank 4a of the first tank, the exhausted ozone gas is operated by operating the valve 22. By switching the destination of 21 to the ozone reaction tanks 4b and 4c of the second tank and the third tank, the exhausted ozone gas 21 can be reused. Since the intake side of the mixing pump 18 sucks a fixed amount of gas, the exhausted ozone gas 21 can be returned to the ozone reaction tanks 4b and 4c without installing a pump or the like.

  According to the present embodiment, the amount of ozone gas used in the laundry waste liquid treatment device can be further reduced by returning the exhausted ozone gas 21 to the ozone reaction tanks 4a, 4b, 4c, and the exhausted ozone gas 21 is changed by switching the valve 22. The ozone generator 15 can be downsized by changing the flow of return.

  Furthermore, the present invention is not limited to the above-described embodiments, and each of the embodiments of the present invention, for example, the air diffuser plate 16 of the first embodiment is replaced with the second and third embodiments. Various modifications can be made without departing from the gist of the present invention in combination with, for example, the bubbles becoming smaller by use in the examples.

The block diagram which shows the washing | cleaning waste liquid processing apparatus of the 1st Embodiment of this invention. The block diagram which shows the basic composition of a washing waste liquid processing apparatus. The block diagram which shows the washing waste liquid processing apparatus of the 2nd Embodiment of this invention. The block diagram which shows the washing | cleaning waste liquid processing apparatus of the 3rd Embodiment of this invention. The block diagram which shows the Example of the ozone injection | pouring in the washing waste liquid processing apparatus of FIG. The block diagram which shows the other Example of the ozone injection | pouring in the washing waste liquid processing apparatus of FIG. The block diagram which shows the washing waste liquid processing apparatus of the 4th Embodiment of this invention. The block diagram which shows the Example which returns the ozone ozone gas in the washing waste liquid processing apparatus of FIG. 7 to an ozone reaction tank.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Washing machine, 2 ... Washing waste liquid, 3 ... Collection tank, 4, 4a, 4b, 4c ... Ozone reaction tank, 5 ... Filter, 6 ... Sample tank, 7 ... Waste ozone decomposition tower, 8 ... Ozone gas, 9 ... Discharge Ozone gas, 10, 11, 12 ... pump, 13 ... filter aid tank, 14 ... heater, 15 ... ozone generator, 16 ... diffuser plate or diffuser cylinder, 17 ... ozone treated water receiving tank, 18 ... mixing pump, 19 ... fine bubble generator, 20, 22 ... valve, 21 ... exhausted ozone gas, 30 ... treatment liquid.

Claims (8)

A collection tank for storing the washing waste liquid discharged from the washing facility of the nuclear power plant;
A filter aid tank for adding a filter aid to the washing waste liquid introduced from the collection tank in advance;
An ozone generator for generating ozone gas;
Washing waste liquid to which the filter aid is added and at least one ozone reaction tank into which the ozone gas is introduced;
Gas-liquid mixing means provided inside or outside of the ozone reaction tank to promote the oxidative decomposition of organic matter contained in the washing waste liquid by mixing the washing waste liquid and the ozone gas,
A filter that removes solids in the laundry waste liquid that has undergone oxidative decomposition;
A sample tank in which water quality is checked before the washing waste liquid from which the solid content has been removed is temporarily stored and released to the environment;
A waste ozone decomposition tower filled with a deutilized catalyst that decomposes ozone gas that was not used for oxidative decomposition in the ozone reaction tank;
A laundry waste liquid treatment apparatus comprising:   2. The laundry waste liquid treatment apparatus according to claim 1, wherein the filter aid is a powdered metal oxide selected from iron-based, manganese-based and copper-based single compounds and compounds.   The laundry waste liquid treatment apparatus according to claim 1 or 2, wherein the filter aid is a powdered metal oxide having a particle size of 0.5 µm to 50 µm.   4. The laundry waste liquid treatment apparatus according to claim 1, wherein the filter aid is injected in a range of 1 ppm to 1000 ppm as a concentration to be added to the laundry waste liquid.   The laundry liquid processing apparatus according to any one of claims 1 to 4, wherein the gas-liquid mixing unit further includes a bubble forming unit that promotes bubble formation of the ozone gas.   The laundry wastewater treatment apparatus according to any one of claims 1 to 5, further comprising a valve for switching the flow of the ozone gas between the ozone generator and the ozone reaction tank.   The laundry waste liquid treatment device according to any one of claims 1 to 6, further comprising a valve for returning the exhausted ozone gas discharged from the ozone reaction tank to the ozone reaction tank. Washing waste liquid discharged from the washing facility of the nuclear power plant is stored in a collection tank;
Adding a filter aid to the washing waste liquid introduced from the collection tank in advance;
The step of introducing the washing waste liquid to which the filter aid is added and the ozone gas are introduced into at least one ozone reaction tank, and the washing waste liquid and ozone gas are mixed to promote the oxidative decomposition of the organic matter contained in the washing waste liquid;
A step of removing a solid content in the waste solution of oxidative decomposition by a filter;
A step of performing a water quality check before the washing waste liquid from which the solid content has been removed is temporarily stored and released to the environment;
A step in which ozone gas that has not been used for oxidative decomposition in the ozone reaction tank is decomposed using a deutilizing catalyst;
A laundry waste liquid treatment method comprising the steps of:

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