JPWO2013031689A1 - Method and apparatus for purifying radioactive material and / or heavy metal-containing water - Google Patents

Abstract

A method for purifying radioactive material and / or heavy metal-containing water, wherein solid matter-liquid separation treatment is performed after mixing humic substances with radioactive material and / or heavy metal-containing water. Efficient removal of radioactive materials and / or heavy metals from seawater, river water, ground water, wastewater treated water, etc. containing radioactive materials and / or heavy metals, and production of safe water that can be discharged or reused. In addition, the treatment of waste mud components containing high concentrations of radioactive substances and / or heavy metals enriched with radioactive substances and / or heavy metals is easily performed.

Description

  The present invention relates to a method and a purification device for purifying seawater, river water, groundwater, wastewater treated water containing radioactive substances and / or heavy metals.

  In recent years, processing of spent nuclear fuel has become a very important issue in nuclear power generation that plays a central role in power energy production systems. 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 recover water safely. Also, 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 radioactivity 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.

  In the period of high economic growth, serious serious illnesses caused by heavy metal contamination such as Minamata disease caused by mercury and Itai Itai disease caused by cadmium became a problem. Even today, factories in various industries that handle heavy metals produce a large amount of process wastewater containing heavy metals. As with the removal of radioactive substances, it is possible to separate and remove heavy metals from process wastewater and recover safe water. is important.

  As a method for separating and removing radioactive substances and heavy metals in water, there is a method in which an aggregating agent of aluminum or iron is added, and agglomerated flocs made of radioactive substances or heavy metals are removed by solid-liquid separation. For example, non-patent literature 1. Further, there is a method of removing it by adsorbing it on an adsorbent such as activated carbon, ion exchange resin, or zeolite. Furthermore, as shown in Patent Document 3 and Non-Patent Document 3, various membrane separation applications have been attempted.

JP 58-156898 A JP 2000-9892 A Japanese Patent Laid-Open No. 61-116695

Journal of the Water Works Association Vol. 80, No. 4, “Review on Removal Performance of Radioactive Substances in Water Purification Process”, April 2011 National Institute for Materials Science, Innovative Practical Nuclear Technology Development Cost Subsidy Project 2003 Summary Report, “Technology Concerning Radioactive Iodine Disposal”, March 2004 IAEA, “Application of Membrane Technologies for Liquid Radioactive Waste Processing”, November 2004

  However, the methods using adsorbents such as flocculants, activated carbon, ion exchange resins, and zeolites exemplified in Non-Patent Documents 1 and 2 and Patent Documents 1 and 2 increase the amount of waste containing radioactive substances and heavy metals. Or the cost of the flocculant and the adsorbent increases. In addition, adsorbents such as activated carbon, ion exchange resin, and zeolite are generally packed in an adsorption device and used, so it is possible to take out adsorbents enriched with radioactive substances and heavy metals online. It was difficult and there was a problem in removing the adsorbent in which radioactive materials and heavy metals were concentrated safely.

  Even when the membrane separation shown in Patent Literature 3 and Non-Patent Literature 3 is applied, a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane) (hereinafter, these are collectively referred to as MF / UF membrane). In the membrane separation using), radioactive substances and heavy metals may permeate the membrane, and are referred to as reverse osmosis membrane (RO membrane) or nanofiltration membrane (NF membrane) (hereinafter collectively referred to as semipermeable membrane). In the case of the membrane separation using), particularly when the salinity of the raw wastewater is high, the recovery rate cannot be increased and the efficiency is poor.

  An object of the present invention is to efficiently remove radioactive substances and / or heavy metals from seawater, river water, groundwater, wastewater-treated water and the like containing radioactive substances and / or heavy metals.

In order to solve the above problems, the method for purifying radioactive substances and / or heavy metal-containing water of the present invention has the following configuration. That is,
This is a method for purifying radioactive material and / or heavy metal-containing water, in which humic substances are mixed into radioactive material and / or heavy metal-containing water and then subjected to solid-liquid separation treatment.

Moreover, the radioactive substance of this invention and / or the purification apparatus of heavy metal containing water have the following structures. That is,
A radioactive substance comprising a humic substance supply unit for supplying humic substance to radioactive substance and / or heavy metal-containing water, and a solid-liquid separation unit for subjecting the radioactive substance and / or mixed water containing heavy metal and humic substance to solid-liquid separation, and A device for purifying heavy metal-containing water.

  The method for purifying radioactive material and / or heavy metal-containing water of the present invention is selected from the group consisting of a flocculant and an adsorbent after mixing humic substances with the radioactive material and / or heavy metal-containing water and before solid-liquid separation treatment. It is preferable to add at least one additive.

  In the method for purifying radioactive material and / or heavy metal-containing water of the present invention, after the solid-liquid separation treatment, at least one additive selected from the group consisting of a flocculant and an adsorbent is added, and then the second solid-liquid It is preferable to perform a separation process.

  In the method for purifying radioactive substances and / or heavy metal-containing water of the present invention, a third method is provided for cleaning wastewater resulting from the step of performing solid-liquid separation and / or cleaning wastewater resulting from the step of performing second solid-liquid separation. It is preferable to perform the solid-liquid separation process.

  In the method for purifying radioactive material and / or heavy metal-containing water of the present invention, at least part of the treated water obtained by the solid-liquid separation treatment and / or the treated water obtained by the second solid-liquid separation treatment is used as the radioactive substance. It is preferable to reflux to heavy metal-containing water.

  In the method for purifying radioactive substance and / or heavy metal-containing water of the present invention, the treated water obtained by the solid-liquid separation treatment and / or the treated water obtained by the second solid-liquid separation treatment is treated by the semipermeable membrane unit. It is preferable.

  In the method for purifying radioactive substance and / or heavy metal-containing water of the present invention, it is preferable to treat the permeated water after the semipermeable membrane unit treatment with an adsorption unit.

  The apparatus for purifying radioactive material and / or heavy metal-containing water of the present invention adds at least one additive selected from the group consisting of a flocculant and an adsorbent to the mixed water containing the radioactive material and / or heavy metal and humic substance. It is preferable that an additive supply unit is provided.

  The radioactive substance and / or heavy metal-containing water purification device of the present invention is a second device in which at least one additive selected from the group consisting of a flocculant and an adsorbent is added after the solid-liquid separation process in the solid-liquid separation unit. An additive supply unit, and a second solid-liquid separation unit that performs a solid-liquid separation process on mixed water containing the additive added by the second additive supply unit to the treated water obtained by the solid-liquid separation process It is preferable.

  The radioactive substance and / or heavy metal-containing water purification apparatus of the present invention is a third solid-liquid separation that performs solid-liquid separation treatment on the washing wastewater generated from the solid-liquid separation unit and / or the washing wastewater produced from the second solid-liquid separation unit. It is preferable to have a unit.

  The apparatus for purifying radioactive material and / or heavy metal-containing water according to the present invention comprises solid-liquid separation of at least part of the treated water obtained by the solid-liquid separation unit and / or the treated water obtained by the second solid-liquid separation unit. It is preferable to provide a solid-liquid separation treated water reflux line for refluxing upstream of the unit.

  The apparatus for purifying radioactive substance and / or heavy metal-containing water of the present invention is a semi-permeable membrane treatment for semi-permeable membrane treatment of treated water obtained by a solid-liquid separation unit and / or treated water obtained by a second solid-liquid separation unit. It is preferable to have a membrane unit.

  The apparatus for purifying radioactive substance and / or heavy metal-containing water of the present invention treats water obtained by solid-liquid separation treatment and / or treated water obtained by solid-liquid separation to permeate after semi-permeable membrane unit treatment. It is preferable to have an adsorption unit.

  According to the present invention, radioactive water and / or heavy metals can be efficiently removed from seawater, river water, groundwater, wastewater treated water, etc. containing radioactive materials and / or heavy metals, and safe water that can be discharged or reused is produced. It becomes possible to do. Further, it is possible to easily treat the waste mud component containing a radioactive substance and / or heavy metal concentrated at a high concentration.

It is a schematic flowchart which shows the one aspect | mode of the purification apparatus of the radioactive substance of this invention and / or heavy metal containing wastewater. It is a schematic flowchart which shows another one aspect | mode of the purification apparatus of the radioactive substance and / or heavy metal containing wastewater of this invention. It is a schematic flowchart which shows another one aspect | mode of the purification apparatus of the radioactive substance of this invention and / or heavy metal containing wastewater. It is a schematic flowchart which shows another one aspect | mode of the purification apparatus of the radioactive substance of this invention and / or heavy metal containing wastewater.

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

  The purification apparatus for radioactive substance and / or heavy metal-containing water according to the present invention includes a raw waste water storage tank 1 for storing radioactive substance and / or heavy metal-containing waste water, a first solid-liquid separation unit 2 for filtering raw waste water, A first solid-liquid separation unit supply pump 3 for supplying raw wastewater to the first solid-liquid separation unit 2; a raw wastewater supply line 4 for supplying raw wastewater to the first solid-liquid separation unit 2; and containing humic substances A humic-containing liquid storage tank 5 that stores liquid, a humic-containing liquid supply pump 6 that supplies humic-containing liquid to raw wastewater, and a first additive storage that stores additives such as a flocculant and an adsorbent. The tank 7, the first additive supply pump 8 that supplies additives such as flocculant and adsorbent to the mixed water containing raw wastewater and humic substances, and the filtered water of the first solid-liquid separation unit 2 Solid-liquid separation unit filtered water return to the raw wastewater storage tank 1 9a, a first semipermeable membrane unit 10 that obtains permeated water and concentrated water by filtering the treated water obtained in the solid-liquid separation treatment, and the first semipermeable membrane unit 10 in the solid-liquid separation treatment. The first booster pump 11 that supplies the treated water obtained, the adsorption unit 12 that adsorbs the permeated water of the first semipermeable membrane unit 10, and the concentrated water of the first semipermeable membrane unit 10 are stored. A first semipermeable membrane unit concentrated water storage tank 13 and an energy recovery unit 14 for recovering the pressure energy of the concentrated water of the first semipermeable membrane unit 10 are provided.

  In the radioactive substance and / or heavy metal-containing wastewater purification apparatus shown in FIG. 1, raw wastewater is temporarily stored in the raw wastewater storage tank 1 and then supplied to the raw wastewater supply line 4 by the first solid-liquid separation unit supply pump 3. Is done. After the humic substance-containing liquid stored in the humic substance-containing liquid storage tank 5 is supplied from the humic substance-containing liquid supply pump 6 to the raw waste water supply line 4, the raw waste water and the humic substance-containing liquid are in the raw waste water supply line 4. And the mixed water is supplied to the first solid-liquid separation unit 2 for solid-liquid separation (invention of claim 1). Here, the first solid-liquid separation unit 2 is intended for removal of radioactive substances and / or a mixture of heavy metals and humic substances, and is used for sedimentation separation, flotation separation, sand filtration, centrifugation, adsorption, precision membrane filtration and limiting. Outer membrane filtration is mentioned, and it is preferable to apply membrane filtration from the viewpoint of reliably separating and removing a mixture of radioactive substances and / or heavy metals and humic substances. In FIG. 1, the radioactive material and / or heavy metal-containing water and the humic substance-containing liquid are mixed in the raw wastewater supply line 4, but they are mixed in a mixing tank equipped with a stirrer, or the radioactive substance and / or heavy metal-containing water. It is also preferable to provide an in-line mixer immediately after mixing the humic substance-containing liquid.

  A radioactive substance is a generic name for substances having radioactivity, such as iodine, cesium, cobalt, ruthenium, uranium, plutonium, radium, strontium, barium, selenium, zirconium, niobium, molybdenum, technetium, tellurium, lanthanum, cerium, ytterbium, Examples include nuclear fuel materials such as iridium and americium, and radioactive elements. The heavy metal is a general term for metals having a specific gravity of 4 to 5 or more, but in the present invention, noble metals such as gold, silver and platinum, lead other than radioactive substances such as uranium and plutonium, zinc, copper, It means cadmium, mercury, arsenic, etc.

  Humic substances are macromolecular organic substances synthesized by various biological and abiotic processes associated with the decomposition and corrosion of plants. They have a complex chemical structure, are indegradable and have a dark color, etc. It is a substance with characteristics, and is roughly divided into humic acid and fulvic acid. Fulvic acid is an organic substance extracted from soil or sediment by alkali or dissolved in water that does not precipitate even under strong acidity. Specifically, it is a corrosive substance rich in carboxyl groups, It is a relatively small organic substance having various molecular weights of several hundreds or less, such as sugars, glycosides, and phenolic substances. On the other hand, humic acid is a reddish brown or dark brown organic substance extracted from soil, lake and seabed sediments, sedimentary rocks and the like by alkali and precipitated by acid, and is a relatively large organic substance having a molecular weight of 1,000 or more.

  In the present invention, as the humic substance-containing liquid, a solution prepared by commercially available humic acid or fulvic acid having a relatively known chemical structure may be used. However, humic soil or dead leaves are immersed in water or an alkaline solution. The humic substance extract obtained in this manner, surface water, seawater, sewage, agricultural wastewater, or the like containing a large amount of humic substances or concentrated water obtained by concentrating them may be used. In the case of a humic substance in which humic acid and fulvic acid coexist, humic acid and fulvic acid may be fractionated using the property that humic acid is precipitated with acid and fulvic acid is not precipitated with acid.

  In the purification method of the present invention, the humic substance concentration of the humic substance-containing liquid is preferably 5 mg-C / L or more, more preferably 10 mg-C / L or more. When the humic substance concentration of the humic substance-containing liquid is within this preferred range, radioactive substances and heavy metals can be sufficiently captured, and the removal rate can be sufficiently increased.

  In the purification method of the present invention, a humic substance having affinity for a radioactive substance and heavy metal is added to the radioactive substance and / or heavy metal-containing water, and the mixture of the radioactive substance and / or heavy metal and humic substance is subjected to solid-liquid separation. It is characterized by purifying water, but using the property that humic acid is insolubilized by acid, it is adjusted to strong acidity in front of solid-liquid separation unit 2, and a mixture of radioactive substances and / or heavy metals and humic acid is prepared. It is also preferable to perform solid-liquid separation after insolubilization.

  In the purification method of the present invention, as the pretreatment of the first solid-liquid separation unit 2, it is preferable to add at least one additive selected from the group consisting of a flocculant and an adsorbent and then perform the solid-liquid separation treatment ( Invention of Claim 2). In this way, the removal rate in the first solid-liquid separation unit 2 can be increased even when the size of the radioactive substance and / or the mixture of heavy metal and humic substance is small.

  The flocculant is an additive for flocking humic acid, radioactive substances and heavy metals in water, and is roughly classified into an inorganic flocculant and an organic polymer flocculant. Inorganic flocculants include aluminum flocculants such as aluminum sulfate (sulfuric acid band) and polyaluminum chloride (PAC), and iron flocculants such as ferric chloride and polyferric sulfate. In addition, the polymer organic flocculants include cationic polymer flocculants such as aminoalkyl (meth) acrylate quaternary salt (co) polymers, anionic polymer flocculants such as acrylamide / sodium acrylate copolymers, There are nonionic polymer flocculants such as polyacrylamide, which can be used alone or in combination with inorganic flocculants, but organic polymer flocculants can be used rather than inorganic flocculants. Since it can suppress generation | occurrence | production of sludge, it is preferable to use an organic type polymer flocculant together rather than using an inorganic type flocculant alone. In addition, since the effect of aggregation is greatly affected by the pH, it is preferable to adjust the pH to an appropriate range using an alkali such as caustic soda, lime or sodium bicarbonate, or an acid such as hydrochloric acid or sulfuric acid.

  An adsorbent is an additive that adsorbs relatively small organic substances such as fulvic acid having a molecular weight of several hundred or less in water, radioactive substances, and heavy metals on a solid surface, and includes activated carbon, ion exchange resin, zeolite, bentonite, and the like. From the viewpoint of relatively easy handling, it is preferable to use powdered activated carbon.

  The additive in the first additive storage tank 7 is preferably selected as appropriate depending on the characteristics of the humic substance-containing liquid in the humic substance-containing liquid storage tank 5. For example, when the humic substance-containing liquid exists in a high proportion of humic acid alone or humic acid, it is preferable to use a flocculant as an additive, and the humic substance-containing liquid exists in a high proportion of fulvic acid alone or fulvic acid It is preferable to use an adsorbent as an additive. Further, when humic acid and fulvic acid coexist in the humic substance-containing liquid, a flocculant and an adsorbent may be used in combination.

  In the purification method of the present invention, after the solid-liquid separation process in the first solid-liquid separation unit 2, at least one additive selected from the group consisting of a flocculant and an adsorbent is added, and then the second solid-liquid separation Solid-liquid separation is preferably performed by the separation unit 16 (invention of claim 3). In this way, the raw wastewater containing radioactive substances and / or heavy metals may contain suspended substances, organic substances such as sugars and proteins, and inorganic substances such as iron and aluminum. In addition, the binding between the radioactive substance and / or the mixture of heavy metal and humic substance and the additives such as the flocculant and the adsorbent is hardly inhibited. The additive in the second additive reservoir 17 shown in FIG. 2 may be the same additive as the additive in the first additive reservoir 7, but humic acid and fulvic acid are contained in the humic substance-containing liquid. May coexist with an additive different from the additive in the first additive storage tank 7.

  In the purification method of the present invention, a part of the filtrate water of the first solid-liquid separation unit 2 is returned to the raw wastewater storage tank 1 by the solid-liquid separation unit filtrate water reflux line 9a and the removal rate of radioactive substances and / or heavy metals is removed. (Invention of claim 5) is preferable. If it does in this way, the removal rate of the radioactive substance and / or heavy metal in the 1st solid-liquid separation unit 2 can be raised.

  Further, in the purification method of the present invention, it is also preferable that a part of the filtrate water of the second solid-liquid separation unit 16 is returned to the raw wastewater storage tank 1 through the solid-liquid separation unit filtrate water reflux line 9b (claimed). Item 5). In this way, the removal rate of radioactive substances and / or heavy metals can be increased. Furthermore, as shown in FIG. 2, a part of the filtered water of the first solid-liquid separation unit 2 is returned to the raw wastewater storage tank 1 in the solid-liquid separation unit filtered water reflux line 9a, and the second solid-liquid separation unit 2 is recirculated. It is also preferable that a part of the filtrate water of the liquid separation unit 16 is returned to the raw wastewater storage tank 1 at the same time in the solid-liquid separation unit filtrate water reflux line 9b.

  In the purification method of the present invention, it is preferable that the treated water obtained by the solid-liquid separation treatment and / or the treated water obtained by the second solid-liquid separation treatment is separated by a semipermeable membrane unit (claim 6). invention). In this way, radioactive substances and / or heavy metals that could not be removed by the first solid-liquid separation unit 2 can be effectively removed. As shown in FIG. 1, when the filtered water of the first solid-liquid separation unit 2 is separated by the first semipermeable membrane unit 10 to be separated into permeated water and concentrated water, the water quality is satisfied as it is. The permeated water can be discharged or reused as purified water.

  In the purification method of the present invention, it is preferable that the permeated water of the semipermeable membrane unit 10 is subsequently treated by the adsorption unit 12. (Invention of Claim 7). In this way, the concentration of radioactive substances and / or heavy metals can be reduced even when the water quality is not satisfactory even after separation treatment with the semipermeable membrane unit. Although not shown in the drawing, when the filtered water of the first solid-liquid separation unit 2 is adsorbed by the adsorption unit and the water quality is satisfactory, it can be discharged or reused as purified water as it is. Subsequently, treatment with a semipermeable membrane unit may be performed to reduce the concentration of radioactive substances and / or heavy metals. Moreover, after processing the filtered water of the 1st solid-liquid separation unit 2 with each of the 1st semipermeable membrane unit 10 and the adsorption | suction unit 12, you may mix and discharge or reuse. Here, the applicable adsorption unit 12 is not particularly limited as long as it can adsorb radioactive substances and / or heavy metals such as activated carbon and ion exchange resin, but it has high adsorption efficiency and can be desorbed and regenerated. From this viewpoint, an anion exchange resin is optimal. By the way, the concentrated water of the first semipermeable membrane unit 10 is stored in the first semipermeable membrane unit concentrated water storage tank 13 after the pressure energy is recovered by the energy recovery unit 14 as necessary.

  Although FIG. 1 illustrates the case where the semipermeable membrane unit is a single stage having only the first semipermeable membrane unit 10, as shown in FIG. 3, the semipermeable membrane unit is replaced with the first semipermeable membrane unit 10. It is also possible to have a plurality of stages such as two stages of the second semipermeable membrane unit 20. In this case, it is possible to provide the intermediate water tank 19 and the second booster pump 21 of the second semipermeable membrane unit 20, or the permeation side of the first semipermeable membrane unit 10 and the second semipermeable membrane unit. It is also possible to omit the intermediate water tank 19 or to omit the second booster pump 21 by directly connecting the supply side.

  The recovery rates of the first semipermeable membrane unit 10 and the second semipermeable membrane unit 20 are adjusted, and the second semipermeable membrane unit concentrated water is first fed through the second semipermeable membrane unit concentrated water reflux line 22. It is also possible to return to the upstream side of the semipermeable membrane unit 10 and control so that the quality of the purified water can be satisfied at a certain level.

  By the way, as shown in FIG. 4, sedimentation sludge and washing waste water are generated from the first solid-liquid separation unit 2. In particular, when the first solid-liquid separation unit 2 is sand filtration or membrane separation, regular backwashing is necessary, so that the treated water obtained from the first solid-liquid separation unit 2 is about 2 to 10%. Produces an amount of cleaning wastewater. Therefore, it is preferable to further separate the cleaning wastewater by the third solid-liquid separation unit 26 to reduce the volume of the cleaning wastewater (the invention of claim 4). Accordingly, it is possible to reduce the volume of washing wastewater containing radioactive substances generated from the first solid-liquid separation unit 2. Here, as the third solid-liquid separation unit 26, a membrane separation apparatus is suitable. In particular, a type in which the third solid-liquid separation unit 26 is immersed in a backwash waste water storage tank 25 as shown in FIG. Are preferred.

  Further, although not shown in FIG. 4, the sedimentation sludge and washing waste water of the second solid-liquid separation unit 16 are further separated by the third solid-liquid separation unit 26 to reduce the washing waste water volume. Is more preferable. That is, it is more preferable that the washing wastewater generated from the first solid-liquid separation unit 2 and / or the washing wastewater generated from the second solid-liquid separation unit 16 is subjected to solid-liquid separation processing by the third solid-liquid separation unit 26.

  As the backwash water supplied to the first solid-liquid separation unit 2 or the second solid-liquid separation unit 16, the solid-liquid separation unit transferred from the solid-liquid separation unit treatment water tank 23 to the backwash water storage tank 24. Treated water may be used, or the concentrated water of the first semipermeable membrane unit 10 or the second semipermeable membrane unit 20 may be stored in the backwash water storage tank 24 and used. If the sludge 27 accumulated in the third solid-liquid separation unit 26 can be disposed as it is, it is preferable to separate the sludge 27 into the dewatered sludge 29 and the sludge recovered water 30 through the sludge dewatering unit 28 as shown in FIG. It is an aspect.

  Furthermore, it is preferable to reduce the volume of the concentrated water of the first semipermeable membrane unit 10. 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.

  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.

  As the semipermeable membrane material, a polymer material such as cellulose acetate polymer, polyamide, polyester, polyimide, vinyl polymer can be used. 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 effect 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 compound that forms a complex with a metal, 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 the first solid-liquid separation unit 2, gravity filtration with a naturally flowing down method can be applied, or pressure filtration with sand filled in a pressurized tank is applied. It is also possible to do. 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 membrane material 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.

  According to the present invention, radioactive water and / or heavy metals can be efficiently removed from seawater, river water, groundwater, wastewater treated water, etc. containing radioactive materials and / or heavy metals, and safe water that can be discharged or reused is produced. It becomes possible to do. Further, it is possible to easily treat the waste mud component containing a radioactive substance and / or heavy metal concentrated at a high concentration.

1: Raw waste water storage tank 2: First solid-liquid separation unit 3: First solid-liquid separation unit supply pump 4: Raw waste water supply line 5: Humic substance-containing liquid storage tank 6: Humic substance-containing liquid supply pump 7: 1st additive storage tank 8: 1st additive supply pump 9a, 9b: Solid-liquid separation unit treated water reflux line 10: 1st semipermeable membrane unit 11: 1st pressurization pump 12: Adsorption unit 13: First semipermeable membrane unit concentrated water storage tank 14: Energy recovery unit 15: Second solid-liquid separation unit supply pump 16: Second solid-liquid separation unit 17: Second additive storage tank 18: Second Additive supply pump 19: Intermediate water tank 20: Second semipermeable membrane unit 21: Second booster pump 22: Second semipermeable membrane unit concentrated water reflux line 23: Solid-liquid separation unit treated water storage tank 24: Reverse Wash water storage tank 2 : Backwash effluent storage tank 26; the third solid-liquid separation unit 27: Sludge 28: sludge dewatering unit 29: dehydrated sludge 30: Sludge collected water

Claims (14)

A method for purifying radioactive material and / or heavy metal-containing water, wherein solid matter-liquid separation treatment is performed after mixing humic substances with radioactive material and / or heavy metal-containing water. The radioactive material according to claim 1, wherein at least one additive selected from the group consisting of a flocculant and an adsorbent is added after mixing the humic substance with the radioactive substance and / or heavy metal-containing water and before the solid-liquid separation treatment. A method for purifying water containing substances and / or heavy metals. The radioactive substance according to claim 1 or 2, wherein after the solid-liquid separation treatment, at least one additive selected from the group consisting of a flocculant and an adsorbent is added, and then a second solid-liquid separation treatment is performed. Or a method for purifying heavy metal-containing water. The third solid-liquid separation treatment is performed on the washing wastewater generated from the step of performing the solid-liquid separation treatment and / or the washing wastewater generated from the step of performing the second solid-liquid separation treatment. The radioactive substance and / or heavy metal containing water purification method of description. The treated water obtained by the solid-liquid separation treatment and / or at least a part of the treated water obtained by the second solid-liquid separation treatment is refluxed to the radioactive substance and / or heavy metal-containing water. The method for purifying radioactive material and / or heavy metal-containing water described in 1. The radioactive substance according to any one of claims 1 to 5 and / or treating the treated water obtained by the solid-liquid separation treatment and / or the treated water obtained by the second solid-liquid separation treatment with a semipermeable membrane unit. A method for purifying heavy metal-containing water. The method for purifying radioactive material and / or heavy metal-containing water according to claim 6, wherein the permeated water after the semipermeable membrane unit treatment is treated with an adsorption unit. A radioactive substance comprising a humic substance supply unit for supplying humic substance to radioactive substance and / or heavy metal-containing water, and a solid-liquid separation unit for subjecting the radioactive substance and / or mixed water containing heavy metal and humic substance to solid-liquid separation, and / Or purification equipment for heavy metal-containing water. The radioactive substance according to claim 8, further comprising an additive supply unit for adding at least one additive selected from the group consisting of a flocculant and an adsorbent to the mixed substance containing the radioactive substance and / or heavy metal and humic substance. And / or purification equipment for heavy metal-containing water. A second additive supply unit for adding at least one additive selected from the group consisting of an aggregating agent and an adsorbent after the solid-liquid separation treatment in the solid-liquid separation unit; and the treated water obtained by the solid-liquid separation treatment The radioactive substance and / or heavy metal content of Claim 8 or 9 provided with the 2nd solid-liquid separation unit which carries out the solid-liquid separation process of the mixed water containing the additive added by the 2nd additive supply unit to Water purification equipment. The radioactive substance according to any one of claims 8 to 10, further comprising a third solid-liquid separation unit for performing solid-liquid separation processing on the washing waste water generated from the solid-liquid separation unit and / or the washing waste water generated from the second solid-liquid separation unit. Purification equipment for water containing substances and / or heavy metals. A solid-liquid separation treated water reflux line for refluxing at least part of the treated water obtained by the solid-liquid separation unit and / or the treated water obtained by the second solid-liquid separation unit is provided. The radioactive substance in any one of Claims 8-11 and / or the purification apparatus of heavy metal containing water. 13. The semipermeable membrane unit according to any one of claims 8 to 12, further comprising a semipermeable membrane unit for treating the treated water obtained by the solid-liquid separation unit and / or the treated water obtained by the second solid-liquid separation unit. Equipment for purifying radioactive material and / or heavy metal-containing water. 14. The adsorption unit according to claim 8, further comprising an adsorption unit for treating the water obtained by the solid-liquid separation treatment and / or the treated water obtained by the solid-liquid separation with the permeated water after the semipermeable membrane unit treatment. Equipment for purifying radioactive material and / or heavy metal-containing water.

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