WO2012144384A1 - Method for purifying water containing radioactive halogen, process for producing filtrate water, and device for purifying water containing radioactive halogen - Google Patents

Abstract

The present invention relates to a method and a device for purifying water that contains a radioactive halogen, in which the water containing a radioactive halogen is regulated so as to have an oxidation/reduction potential of 800 mV or less and subjected to solid-liquid separation, and the obtained pretreated water is then regulated so as to have an oxidation/reduction potential of 500 mV or less and treated with a semipermeable-membrane unit to separate the pretreated water into concentrated wastewater and filtrate water. The radioactive halogen, in particular, radioactive iodine, is thereby removed from the water, e.g., seawater, river water, groundwater, or treated wastewater, which contains the radioactive halogen. Thus, the radioactive iodine contained in a slight amount in water is efficiently removed.

Description

Method for purifying radioactive halogen-containing water, method for producing permeated water, and device for purifying radioactive halogen-containing water

The present invention relates to a method for purifying seawater, river water, groundwater, wastewater treated water containing radioactive halogen, particularly radioactive iodine, and a device for purifying radioactive halogen-containing water.

In recent years, in the nuclear power generation that plays a central role in the power energy production system, the disposal of spent nuclear fuel has become a very important issue. When recovering and reusing uranium and plutonium from spent nuclear fuel, a large amount of water is used to produce process wastewater containing radioactive materials, especially radioactive iodine. It is required to separate and remove radioactive substances from the process wastewater and to collect safe water. In addition, in the case of periodic repairs or sudden shutdowns of power plant turbines, the process water staying in the facility often contains radioactive iodine, and in the event of a radioactive leak accident Since the water in the natural environment becomes radioactive, it is very important to separate and remove it when the concentration exceeds the allowable range.

As a method of separating and removing radioactive substances in water, a method of adsorbing on activated carbon, ion exchange resin, zeolite, etc. is the most popular, and is exemplified in Non-Patent Document 1 and Patent Documents 1 and 2, for example. Furthermore, recently, as shown in Non-Patent Document 2, various membrane separation applications have been attempted. Further, Patent Document 3 gives an example in which a reducing agent is added to wastewater and then removed with a reverse osmosis membrane capable of removing low molecules.

However, adsorbents are not preferred, especially when the salinity of the raw wastewater is high because the ability to adsorb halogens such as iodine is inhibited by the salinity. In addition, when directly treating high-concentration raw wastewater, there is a problem that radioactive materials are concentrated in the adsorbent itself, and the risk of the treatment facility increases. In addition, the method of removing with a reverse osmosis membrane after adding a reducing agent is easy to achieve a stable state in which iodine is easily removed, but the wastewater is mixed with natural water such as river water or rainwater, or the wastewater itself is natural. When it comes from, the effect of the reducing agent, such as the need to add a large amount of reducing agent in order to form a complex equilibrium state, such as halogen is taken into various impurities to form a complex May not be fully demonstrated.

JP 58-156898 A JP 2000-9892 A JP 61-116695 A

An object of the present invention is to efficiently remove halogens, in particular iodine, from seawater, river water, groundwater, wastewater treated water, etc. containing radioactive halogens.

In order to solve the above problems, the present invention has the following configuration.

(1) Solid-liquid separation by setting the oxidation-reduction potential of radioactive halogen-containing water to 800 mV or less, and then treating it with a semipermeable membrane unit by setting the oxidation-reduction potential of the obtained pretreated water to 500 mV or less. A method for purifying radioactive halogen-containing water separated into water.

(2) The method for purifying radioactive halogen-containing water according to (1), wherein 99% or more of fine particles of 0.45 μm or more are removed by solid-liquid separation.

(3) The method for purifying radioactive halogen-containing water according to (1) or (2), wherein the permeated water after treatment with the semipermeable membrane unit is treated with an adsorption unit.

(4) The method for purifying radioactive halogen-containing water according to (3), wherein the adsorption unit comprises an anion exchanger.

(5) The radioactive halogen-containing water according to any one of (1) to (4), wherein the pH of the permeated water after the treatment with the semipermeable membrane unit is adjusted to 8 or more and further treated with the semipermeable membrane unit Purification method.

(6) The method for purifying radioactive halogen-containing water according to any one of (1) to (5), wherein the washing wastewater for solid-liquid separation is treated with another solid-liquid separation device.

(7) The radioactive halogen according to any one of (1) to (6), wherein the concentrated waste water after the semipermeable membrane unit treatment is further subjected to a semipermeable membrane unit, crystallization or evaporation treatment to obtain purified water Purification method of contained water.

(8) The method for purifying radioactive halogen-containing water according to any one of (1) to (7), wherein deaeration is performed before treatment with the semipermeable membrane unit.

(9) A method for producing permeated water that obtains permeated water by performing the method for purifying radioactive halogen-containing water according to any one of (1) to (8).

(10) A solid-liquid separation unit that obtains pretreatment water by solid-liquid separation of radioactive halogen-containing water, a first oxidation-reduction potentiometer that measures the oxidation-reduction potential before treatment of the solid-liquid separation unit, and pretreatment water A reducing agent addition unit for adding a reducing agent; a semipermeable membrane unit for separating pretreated water to which the reducing agent is added into concentrated wastewater and permeated water; and a second for measuring a redox potential before the semipermeable membrane unit treatment. Purification equipment for radioactive halogen-containing water equipped with a redox potentiometer.

(11) The water purification device according to (10), further comprising an adsorption unit for treating the permeated water of the semipermeable membrane unit.

According to the present invention, it is possible to efficiently remove halogen, particularly iodine, from seawater, river water, groundwater, wastewater treated water, etc. containing radioactive halogen, and to produce safe water that can be discharged or reused. Is possible.

It is a schematic flowchart which shows one embodiment of the purification method of radioactive halogen containing water of this invention. It is a schematic flowchart which shows one embodiment of the purification method of the radioactive halogen containing water which further processes permeated water by a semipermeable membrane unit based on this invention. It is a schematic flowchart which shows one embodiment of the purification method of the radioactive halogen containing water which further processes concentrated water with a semipermeable membrane unit based on this invention. It is a general | schematic flowchart which shows one embodiment of the purification method of the radioactive halogen containing water which treats both permeated water and concentrated water with a semipermeable membrane unit based on this invention. It is a schematic flowchart which shows one embodiment of the purification method of the radioactive halogen containing water which carries out the separation process of the concentrated water by a concentration separation unit based on this invention. It is a schematic flowchart which shows one embodiment of the purification method of the radioactive halogen containing water concerning the present invention which further concentrates the concentrated water with a semipermeable membrane unit and then separates the concentrated separation unit.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to these.

An example of the purification apparatus for radioactive halogen-containing water of the present invention is shown in FIG. In the purification apparatus for radioactive halogen-containing water shown in FIG. 1, raw wastewater 1 is temporarily stored in a wastewater tank 2, then processed by a pretreatment unit 4 by a supply pump 3, and sent to a pretreatment water tank 5. Here, the pretreatment unit 4 is intended to remove suspended substances, and includes sedimentation separation, flotation separation, sand filtration, and membrane filtration. From the viewpoint of the removal of radioactive halogen targeted by the present invention, the flocculant is used. Therefore, it is preferable not to add a flocculant and to apply membrane filtration that can reliably remove suspended components. In addition, when alkali is added for the purpose of increasing the removal rate of radioactive halogen, scale is likely to precipitate, which makes it difficult to concentrate. Furthermore, when an oxidizing agent such as hypochlorous acid, which is generally applied in water treatment water intake, is added, organic substances in the raw wastewater are decomposed to lower the molecular weight, react with halogens, and hypochlorous acid. In the present invention, it should not be added, because the components are complicated by the exchange reaction with the other components and the pretreatment efficiency and removal rate are reduced. Furthermore, even if wastewater is in an oxidized state due to some component, if it is treated as it is, dirt or organic matter adhering to the piping or pretreatment may be decomposed and leaked out, so the wastewater used for pretreatment is oxidized. When the reduction potential is high, it is preferable to prevent the oxidation state by adding a reducing agent in advance. However, if it is reduced to pretreatment, it may become anaerobic and react with the suspension. Therefore, in order to maintain the reduced state at the time when it is supplied to the semipermeable membrane unit, reduction before pretreatment is required. It is preferred to minimize the addition of agents. Specifically, it is preferable that the oxidation-reduction potential is 800 mV or less, preferably 500 mV or less, and 200 mV or more. Of course, wastewater that stays in an anaerobic state in the basement or in the tank may have a redox potential lower than 200 mV in advance. In such a case, there is a problem with supplying it to the pretreatment as it is. Absent. However, since suspended organic matter contained in wastewater is incorporated to some extent by complexing or adsorbing halogen, the oxidation-reduction potential of the wastewater is oxidized by the supply water to the semipermeable membrane unit. If the potential is lower than the reduction potential, the halogen incorporated in the suspension is ionized and solid-liquid separation cannot be performed, and then the redox potential rises and tends to be difficult to remove with a semipermeable membrane unit. It is preferable to lower the oxidation-reduction potential of the pretreatment water supplied to the first semipermeable membrane unit 8 as compared with the oxidation-reduction potential of the wastewater supplied to the unit 4. In addition, it is not deny that the oxidizing agent is added intermittently (for example, several minutes to several tens of minutes / day) for the purpose of cleaning the piping, but it is necessary to pay attention to fluctuations in treated water during that time. Moreover, it is also possible to add a flocculant and an adsorbent only during that time.

After the reducing agent is added in the reducing agent injection unit 6 so that the pretreatment water has an oxidation-reduction potential below the halogen reduction potential, specifically 500 mV or less, preferably 200 mV or less, more preferably 100 mV or less. Then, it is sent to the first semipermeable membrane unit 8 by the first booster pump 7 and separated (first embodiment of the present invention). As described above, even when the oxidation-reduction potential of the waste water is less than 200 mV, the oxidation-reduction potential may rise before being supplied to the first semi-permeable membrane unit 8, so the first semi-permeable membrane unit. The oxidation-reduction potential before being supplied to 8 is measured, and preferably the reducing agent is sufficiently added so that the oxidation-reduction potential of the pretreated water supplied to the first semipermeable membrane unit 8 is 200 mV or less, more preferably Is preferably maintained at 100 mV or less.

Here, the measurement position of the oxidation / reduction potential of the wastewater is preferably in front of the pretreatment unit 4, particularly in the vicinity of the water intake, but even if it is behind the pretreatment unit 4, the object of the present invention is substantially achieved. It is possible to achieve. That is, when a high oxidation-reduction potential is shown at the outlet of the pretreatment unit 4, it is possible to take measures such as adding a reducing agent in front of the pretreatment unit 4. Of course, there is no problem in monitoring the oxidation-reduction potential both before and after the pretreatment unit 4.

In order to suppress the redox potential in front of the first semipermeable membrane unit 8, it is common to monitor the redox potential in front of the semipermeable membrane unit. Monitoring the redox potential, or both. In particular, it is also preferable to prepare for both in consideration of a case where an increase in the redox potential in the semipermeable membrane unit occurs by monitoring both. Furthermore, monitoring the oxidation-reduction potential before and after the reducing agent injection unit 6 makes it easy to control the amount of reducing agent injection, and to easily detect more than injection, which is one of the preferred embodiments.

The redox potential can be measured online or offline using a commercially available ORP meter (redox potential meter). However, when measuring offline, the effects of dissolution of the outside air and temperature changes can be observed. In order to receive, it is preferable to measure online, but it is not particularly limited. Examples of the ORP meter suitable for this application include PH202 (or OR100) / OR8EFG and PH72 / OR72SN manufactured by Yokogawa Electric Corporation.

The separation treatment by the semipermeable membrane has a first purpose of removing iodine. In the present invention, the first semipermeable membrane is obtained by reducing the supply water of the first semipermeable membrane unit 8. Although the removal rate of iodine in the unit 8 can be improved, further, as a second object, other halogens and the like that become inhibitors when being adsorbed in the adsorption unit 12 at the subsequent stage can be removed.

When the water quality is satisfactory, the permeated water of the first semipermeable membrane unit 8 can be discharged or reused as purified water 13 as it is, but subsequently treated by the adsorption unit 12 to reduce the iodine concentration. It is preferable to reduce (the third embodiment of the present invention). Here, the applicable adsorption unit 12 is not particularly limited as long as it can adsorb iodine such as activated carbon or ion exchange resin, but it has high adsorption efficiency and can be desorbed / regenerated. An anion exchange resin is optimal (fourth embodiment of the present invention). By the way, the concentrated waste water of the first semipermeable membrane unit 8 is stored in the concentrated (volume-reduced) water storage tank 24 after the pressure energy is recovered by the energy recovery unit 23 as necessary.

FIG. 1 illustrates the case where the semipermeable membrane unit has one stage, but as shown in FIG. 2, the semipermeable membrane may have a plurality of stages. In this case, it is possible to provide the intermediate water tank 9 and the second booster pump 10, or directly connect the transmission side of the first semipermeable membrane unit 8 and the supply side of the second semipermeable membrane unit 11, It is possible to omit the intermediate water tank 9 or omit the second booster pump 10. Here, for the purpose of enhancing the removal performance of the second semipermeable membrane unit 11, it is possible to add a reducing agent again, but the reducing agent is added in front of the first semipermeable membrane unit 8. In view of this, it is more preferable that the pH be 8 or more, preferably 9 or more, and then supplied to the second semipermeable membrane unit 11 (fifth embodiment of the present invention). That is, depending on the charge characteristics of the semipermeable membrane, when the reducing agent is acidic or neutral, the permeated water of the first semipermeable membrane unit 8 is often shifted to acidic. To increase the pH. In FIG. 2, the concentrated water of the second semipermeable membrane unit 11 is preferably returned to the upstream side of the first semipermeable membrane unit 8 because the iodine concentration is increased.

Regarding the separation performance of the pretreatment unit 4, it is preferable that the suspended substance can be reliably treated without the addition of a flocculant in order to reduce the load on the subsequent semipermeable membrane unit. Specifically, fine particles of 0.45 μm or more can be removed by 95% or more, more preferably 99% or more, and furthermore, 0.01 μm or more of fine particles can be removed by 80% or more, and further 90% or more. Preferably, it can be done (second embodiment of the invention).

Here, when the removal performance of the fine particles of the membrane is 0.45 μm, for example, polystyrene latex fine particles (K045, manufactured by Iwai Chemicals Co., Ltd.) or equivalent are dispersed in 20 ppm of pure water, and the concentration of the filtrate after membrane filtration is measured. Can be obtained. In the case of 0.01 μm, liquids containing 1000 ppm of dextran having different molecular weights (for example, molecular weights of 70 kDa, 100 kDa, 200 kDa, and 500 kDa) are prepared and filtered, respectively. In addition, an approximated curve can be created by the Gompertz function, 150 kDa is regarded as 0.01 μm, and the blocking performance at 150 kDa is estimated.

As a method for obtaining the filtrate, for example, in the case of a flat membrane, a stirring type ultra folder (UHP-43K, capacity 70 mL) having a membrane area of 11.64 cm ² is used, and the dispersion is stirred while being stirred at a pressure of 10 kPa. In the case of hollow fiber membranes, a mini-module having an effective length of about 20 cm × 2 pieces is produced, and the apparent membrane surface linear velocity is 1 to 1.5 m. A method of sampling the filtrate from the point of time when the dispersion liquid is passed through at a pressure of 5 kPa so that 5 times the amount of water inside the hollow fiber membrane is filtered.

By the way, sedimentation sludge and washing waste water are generated from the pretreatment unit 4 used for solid-liquid separation. In particular, when the pretreatment is sand filtration or membrane separation, regular backwashing is necessary, so that about 2-10% of the treated water is discharged. Therefore, as illustrated in FIG. 4, it is preferable to further separate the washing wastewater with another solid-liquid separation unit 17 to reduce the wastewater volume (sixth embodiment of the present invention). As the solid-liquid separation unit 17 used for such an application, a membrane separation apparatus is still suitable, but in particular, a type in which the solid-liquid separation unit 17 is directly immersed in the backwash drainage tank 16 is suitable. . Thereby, the volume of radioactive material generated from the pretreatment unit 4 can be reduced. Moreover, the filtered water obtained by the solid-liquid separation unit 17 can be returned to the waste water tank 2 as illustrated in FIG. 4 or can be returned to the front of the pretreatment unit 4. Furthermore, since some raw wastewater may contain volatile iodine, it can be volatile by degassing it by aeration with a gas that does not contain radioactive materials or contain low concentrations in advance. It is also possible to remove iodine (eighth embodiment of the present invention). Volatile iodine may be difficult to remove with a semipermeable membrane unit depending on the pH or temperature of the wastewater, and this is a preferred embodiment because the amount of added chemicals can be reduced in view of the case of pH adjustment at a later stage.

Furthermore, it is preferable to reduce the volume of the concentrated waste water of the first semipermeable membrane unit 8. The volume reduction method is not particularly limited, but a method using a semipermeable membrane, an evaporation method, and crystallization can be particularly preferably employed (seventh embodiment of the present invention). FIG. 3 illustrates a case where the concentrated wastewater of the first semipermeable membrane unit 8 is processed by the third semipermeable membrane unit 25. In this case, depending on the process and operating conditions, the permeated water 26 of the third semipermeable membrane unit, which has a lower quality than the permeated water of the first semipermeable membrane unit 8, may be generated. There is no problem if it can be properly used depending on the situation, and it is also possible to return to the upstream side of the first semipermeable membrane unit 8.

Here, if copper, cobalt, manganese, or the like is present in the raw wastewater 1, it may react with the reducing agent to generate an oxidizing agent, and the reducing power of the concentrated water that has passed through the first semipermeable membrane unit 8. It is also a preferable aspect that a reducing agent is added again to the concentrated waste water of the first semipermeable membrane unit 8 since the oxidation-reduction potential may increase. In addition, when the pH is lowered by the addition of a reducing agent, the iodine removal performance by the semipermeable membrane tends to decrease, but when the conditions for suppressing the generation of scale in the third semipermeable membrane unit 25 are satisfied, Concentration can be increased, which is a preferred embodiment. Specifically, the pH of the water supplied to the third semipermeable membrane unit 25 is preferably 7 or less.

In FIG. 3, the concentrated water line of the first semipermeable membrane unit 8 and the supply water line to the third semipermeable membrane unit 25 are directly connected to increase the pressure by the intermediate booster pump 28. There is of course no problem that the concentrated water of one semipermeable membrane unit 8 is temporarily stored in an intermediate tank or the like and then supplied again to the third semipermeable membrane unit 25 by a booster pump. As a result, even if the pressure energy of the concentrated water in the first semipermeable membrane unit 8 is recovered, energy loss is inevitable, but the chemical addition can be performed at an open or low pressure.

FIG. 4 shows an example of the case where the second semipermeable membrane unit 11 and the third semipermeable membrane unit 25 are used together. By using such a system, the first semipermeable membrane unit 8 and It is possible to control the recovery rate (= permeate / feed water) of the second semipermeable membrane unit 11 so that the water quality of the purified water 13 is satisfied at a certain level. The fluctuation (that is, the amount of water sent to the concentrated water storage tank 24) can be controlled by the third semipermeable membrane unit 25.

FIG. 5 shows an example in which the concentration separation unit 18 is applied instead of the third semipermeable membrane unit 25, and FIG. 6 shows the separation of the permeated water 26 of the third semipermeable membrane unit 25 by the concentration separation unit 18. Then, an example in which the concentrated water 19 is refluxed upstream of the first semipermeable membrane unit 8 is shown.

In the present invention, it is also a preferred embodiment to obtain permeated water by purifying radioactive halogen-containing water in any of the embodiments of the present invention described above.

The semipermeable membrane unit applicable to the present invention is not particularly limited, but for easy handling, a hollow fiber membrane-like or flat membrane-like semipermeable membrane is housed in a casing to form a fluid separation element (element). It is preferable to use what was loaded in a pressure vessel. When the fluid separation element is formed of a flat membrane, for example, generally a semipermeable membrane is wound in a cylindrical shape together with a flow path material (net) around a cylindrical central pipe having a large number of holes. As commercial products, reverse osmosis membrane element TM700 series and TM800 series manufactured by Toray Industries, Inc. can be mentioned. It is also preferable to configure the semipermeable membrane unit by connecting one or more fluid separation elements in series or in parallel.

Polymer materials such as cellulose acetate polymer, polyamide, polyester, polyimide, vinyl polymer can be used for the semipermeable membrane material. In addition, the membrane structure has a dense layer on at least one side of the membrane, and on the asymmetric membrane having fine pores gradually increasing from the dense layer to the inside of the membrane or the other side, or on the dense layer of the asymmetric membrane. Either a composite film having a very thin functional layer formed of another material may be used.

In the semipermeable membrane unit, the feed water is concentrated. Therefore, scale inhibitors, acids and alkalis are added to the feed water of each semipermeable membrane unit to prevent scale precipitation due to concentration and to adjust pH. It is possible to In addition, it is preferable to implement scale inhibitor addition upstream from pH adjustment so that the addition cost can be exhibited. It is also preferable to prevent an abrupt concentration or pH change in the vicinity of the addition port by providing an in-line mixer immediately after the addition of the chemical, or by directly contacting the addition port with the flow of the supply water. .

The scale inhibitor is a substance that forms a complex with a metal, a metal ion, or the like in a solution and solubilizes the metal or metal salt, and an organic or inorganic ionic polymer or monomer can be used. As organic polymers, synthetic polymers such as polyacrylic acid, sulfonated polystyrene, polyacrylamide, and polyallylamine, and natural polymers such as carboxymethylcellulose, chitosan, and alginic acid can be used, and ethylenediaminetetraacetic acid can be used as a monomer. Moreover, polyphosphate etc. can be used as an inorganic type scale inhibitor. Among these scale inhibitors, polyphosphate and ethylenediaminetetraacetic acid (EDTA) are particularly preferably used from the viewpoints of availability, ease of operation such as solubility, and cost. The polyphosphate refers to a polymerized inorganic phosphate material having two or more phosphorus atoms in a molecule typified by sodium hexametaphosphate and bonded with an alkali metal, an alkaline earth metal and a phosphate atom. Typical polyphosphates include tetrasodium pyrophosphate, disodium pyrophosphate, sodium tripolyphosphate, sodium tetrapolyphosphate, sodium heptapolyphosphate, sodium decapolyphosphate, sodium metaphosphate, sodium hexametaphosphate, and potassium salts thereof. Etc.

On the other hand, sulfuric acid, sodium hydroxide, and calcium hydroxide are generally used as the acid and alkali, but hydrochloric acid, oxalic acid, potassium hydroxide, sodium bicarbonate, ammonium hydroxide, and the like can also be used. However, it is better not to use calcium or magnesium in order to prevent an increase in scale components in seawater.

Here, when sand filtration is used for pretreatment, it is possible to apply gravity-type filtration that naturally flows down, or it is possible to apply pressurized filtration in which a pressure tank is filled with sand. . As the sand to be filled, single-component sand can be applied. For example, anthracite, silica sand, garnet, pumice, and the like can be combined to increase filtration efficiency. The microfiltration membrane and the ultrafiltration membrane are not particularly limited, and a flat membrane, a hollow fiber membrane, a tubular membrane, a pleat type, or any other shape can be used as appropriate. The material of the membrane is also particularly limited, and inorganic materials such as polyacrylonitrile, polyphenylene sulfone, polyphenylene sulfide sulfone, polyvinylidene fluoride, polypropylene, polyethylene, polysulfone, polyvinyl alcohol, cellulose acetate, and ceramics can be used. However, depending on the raw water form, there are some that are prone to deterioration, so care must be taken. Moreover, even if it is a filtration system, any of the pressure filtration system which pressurizes and filters supply water, and the suction filtration system which sucks and filters the permeation | transmission side are applicable.

On the other hand, when the feed water contains a large amount of soluble organic matter, it is also preferable to apply pressurized flotation or activated carbon filtration. In addition, when a large amount of soluble inorganic substance is contained, a chelating agent such as an organic polymer electrolyte or sodium hexametaphosphate may be added, or exchanged with soluble ions using an ion exchange resin or the like. In addition, when iron or manganese is present in a soluble state, it is also preferable to use an aeration oxidation filtration method, a contact oxidation filtration method, or the like.

It is also possible to use a nanofiltration membrane for pretreatment in order to remove specific ions and polymers in advance and operate the purification apparatus for radioactive halogen-containing water of the present invention with high efficiency.

The present invention relates to a method and apparatus for purifying radioactive halogen-containing water that removes radioactive halogen, particularly radioactive iodine, from seawater, river water, groundwater, wastewater-treated water, etc. containing radioactive halogen, and is contained in trace amounts in water. Radioactive iodine can be removed efficiently.

1: Raw waste water 2: Waste water tank 3: Supply pump 4: Pretreatment unit 5: Pretreatment water tank 6: Reductant injection unit 7: First booster pump 8: First semipermeable membrane unit 9: Intermediate water tank 10: Second booster pump 11: Second semipermeable membrane unit 12: Adsorption unit 13: Purified water 14: Valve 15: Backwash water tank 16: Backwash drainage tank 17: Solid-liquid separation unit 18: Concentration separation unit 19: Concentration Water 20: Degassing unit 21: Condensing unit 22: Recovery steam 23: Energy recovery unit 24: Concentrated water storage tank 25: Third semipermeable membrane unit 26: Permeated water 27 of the third semipermeable membrane unit 27: Third Concentrated water 28 of the semipermeable membrane unit: Intermediate pressurizing pump 29: Alkali addition unit

Claims (11)

1. Solid-liquid separation with a redox potential of radioactive halogen-containing water of 800 mV or less, and then treatment with a semipermeable membrane unit with a redox potential of pretreated water of 500 mV or less to separate into concentrated waste water and permeated water. A method for purifying radioactive halogen-containing water.
2. The method for purifying radioactive halogen-containing water according to claim 1, wherein 99% or more of fine particles of 0.45 µm or more are removed by solid-liquid separation.
3. The method for purifying radioactive halogen-containing water according to claim 1 or 2, wherein the permeated water after the semipermeable membrane unit treatment is treated with an adsorption unit.
4. The method for purifying radioactive halogen-containing water according to claim 3, wherein the adsorption unit comprises an anion exchanger.
5. The method for purifying radioactive halogen-containing water according to any one of claims 1 to 4, wherein the pH of the permeated water after the treatment with the semipermeable membrane unit is set to 8 or more, and further the treatment with the semipermeable membrane unit is performed.
6. The method for purifying radioactive halogen-containing water according to any one of claims 1 to 5, wherein the washing wastewater for solid-liquid separation is treated by another solid-liquid separation device.
7. The method for purifying radioactive halogen-containing water according to any one of claims 1 to 6, wherein the purified waste water is further obtained by subjecting the concentrated waste water after the semipermeable membrane unit treatment to a semipermeable membrane unit, crystallization or evaporation treatment. .
8. The method for purifying radioactive halogen-containing water according to any one of claims 1 to 7, wherein deaeration is performed before the treatment with the semipermeable membrane unit.
9. A method for producing permeated water, wherein permeated water is obtained by performing the method for purifying radioactive halogen-containing water according to any one of claims 1 to 8.
10. A solid-liquid separation unit that obtains pretreatment water by solid-liquid separation of radioactive halogen-containing water, a first oxidation-reduction potentiometer that measures the oxidation-reduction potential before treatment of the solid-liquid separation unit, and a reducing agent in the pretreatment water A reducing agent addition unit to be added; a semipermeable membrane unit that separates pretreated water to which the reducing agent is added into concentrated wastewater and permeated water; and a second oxidation-reduction that measures a redox potential before the semipermeable membrane unit treatment. A device for purifying radioactive halogen-containing water with an electrometer.
11. The water purification device according to claim 10, further comprising an adsorption unit for treating the permeated water of the semipermeable membrane unit.

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