JP5300896B2 - Water treatment equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily separate and recover negative ions, as high purity crystal, from discharged water containing negative ions. <P>SOLUTION: A water treatment apparatus for recovering ions from ion-containing water includes: a line for water to be treated; a line for concentrated water; a reaction tank; and a crystal discharging line. The line for water to be treated supplies ion-containing water as water to be treated. The line for concentrated water supplies concentrated seawater obtained in a process of desalination of seawater. The reaction tank produces crystallized ions from the water to be treated by reaction of negative ions contained in the water to be treated supplied through the line for water to be treated with seawater-derived positive ions contained in the concentrated seawater supplied through the line for concentrated water. The crystal discharging line discharges the produced crystal from the reaction tank. <P>COPYRIGHT: (C)2013,JPO&amp;INPIT

Description

  Embodiments of the present invention relate to a water treatment apparatus that collects anions such as phosphate ions contained in water to be treated as crystals.

  In wastewater treatment, various purification methods are applied from the viewpoint of preventing water pollution. In addition, not only is the anion, which is a part of the water-polluting component, separated and removed, but also a technique that collects it after separation and uses it as a resource has attracted attention. Specifically, a reaction crystallization technique in which an ionic component that precipitates crystals in water to be treated containing anions is mixed to precipitate anion crystals is common. With this reactive crystallization technique, crystals can be generated and grown, separated and utilized as resources.

  In the reaction crystallization technique, it is necessary to mix a liquid containing another ionic component for generating a crystal, and it is desirable to reduce the cost and reduce the cost of a drug containing the ionic component to be mixed. Further, when recovered and recycled, it is important to prevent the inclusion of impurities in the recovered crystal and improve the quality of the crystal.

Japanese Patent No. 4310196 JP 2009-56457 A

  In view of the above problems, a water treatment device is provided that can separate anions from anion-containing wastewater with an easy configuration and recover them as high-purity crystals.

  The water treatment apparatus according to the embodiment is a water treatment apparatus that recovers ions from ion-containing water, and includes a water line to be treated, a concentrated water line, a reaction tank, and a crystal discharge line. The water to be treated is supplied with ion-containing water as water to be treated. The concentrated water line is supplied with concentrated seawater obtained when desalinating seawater. The reaction tank reacts the anion contained in the treated water supplied via the treated water line and the cation derived from seawater contained in the concentrated water supplied via the concentrated water line. Ions contained in water to be treated are crystallized. The crystal discharge line discharges the generated crystals from the reaction vessel.

It is a figure explaining the water treatment equipment concerning a 1st embodiment. It is a figure explaining the water treatment apparatus which concerns on 2nd Embodiment.

  Below, the water treatment apparatus which concerns on embodiment of this invention is demonstrated using drawing. This water treatment device is a water treatment device for treating ion-containing water containing an anion component. Specifically, the water treatment apparatus according to the embodiment separates ion components as crystals from the ion-containing wastewater containing ion components such as phosphate ions, sulfate ions, and fluoride ions and the concentrated water of the ion-containing wastewater, to recover. For example, phosphate ions are contained in waste water discharged from sewage treatment plants, food processing plants, and the like. Further, fluoride ions are contained in the waste water discharged from the semiconductor manufacturing factory. Furthermore, sulfate ions are contained in the waste water discharged by the combustion exhaust gas treatment. In the following description, the same components are denoted by the same reference numerals and description thereof is omitted.

<First Embodiment>
As shown in FIG. 1, the water treatment apparatus 1a according to the first embodiment includes a desalination means 10 for desalinating seawater, a reaction tank 18 for crystallizing ions, and ion-containing water (ion ions) containing an anion component. Water to be treated (concentrated water of ion-containing waste water or ion-containing waste water) to the reaction tank 18 as treated water, and seawater concentrated water obtained when the seawater is desalinated by the desalination means 10. Concentrated water line 17 to be supplied to 18, reaction assistant supply device 22 for supplying a reaction aid for promoting crystallization by anion in ion-containing water and cation in concentrated water of seawater to reaction tank 18, and crystallization And a crystal supply device 20 for supplying the seed crystal used in the above to the reaction tank 18.

  The water treatment apparatus 1 a includes a first filtration membrane 12 and a second filtration membrane 15 as seawater desalination means 10. Although the utilization method of the fresh water obtained by this desalination means 10 is not limited, For example, it can utilize for the production of industrial water etc. which are used for power generation using boilers, such as drinking water, nuclear power generation, and thermal power generation.

  Seawater is supplied to the first filtration membrane 12 via the seawater line 11. The first filtration membrane 12 is a membrane that separates solids (contaminants such as marine microorganisms and suspended solids) contained in seawater from seawater. For example, a UF membrane (ultrafiltration membrane) or MF membrane ( Microfiltration membrane). The seawater from which the solid matter has been separated by the first filtration membrane 12 is sent to the second filtration membrane 15 via the first treated water line 13. Further, the solid matter separated from the seawater by the first filtration membrane 12 is discharged from the water treatment device 1 a via the solid matter line 14.

  The second filtration membrane 15 is a membrane that separates salt from seawater from which solids are separated, and is, for example, an RO membrane (reverse osmosis membrane). By separating the salt content with the second filtration membrane 15, the seawater becomes fresh water and is discharged from the water treatment device 1 a via the second treated water line 16. The concentrated seawater separated from the fresh water by the second filtration membrane 15 is sent to the reaction tank 18 via the concentrated water line 17.

  That is, in the water treatment apparatus 1a, the solid matter in the seawater is removed by the first filtration membrane 12, thereby reducing the load on the second filtration membrane 15 and increasing the durability of the second filtration membrane 15. it can. Moreover, it can prevent that the solid substance is contained in the concentrated liquid of seawater by removing the solid substance in seawater with the 1st filtration membrane 12. FIG. Although not shown in FIG. 1, the seawater processed by the desalination means 10 includes microorganisms in the seawater. Therefore, in order to suppress the propagation of such microorganisms, a general desalination apparatus is used. As is done, it is desirable to add a disinfectant and a flocculant in advance.

  Concentrated water is supplied to the reaction tank 18 through the concentrated water line 17, and ion-containing water, which is to-be-treated water, is supplied through the to-be-treated water line 19. The seed crystal is supplied via the reaction auxiliary agent 22, and the reaction auxiliary agent is supplied from the reaction auxiliary agent supply device 22 via the reaction auxiliary agent line 23.

  In the reaction tank 18, seawater-derived cations (calcium ions or magnesium ions) contained in the concentrated water supplied via the concentrated water line 17 and the water to be treated supplied via the water line 19 to be treated. The contained anions react with each other and are deposited on the seed crystal supplied through the crystal supply line 21 to be crystallized. Crystals obtained in the reaction vessel 18 are discharged from the reaction vessel 18 through a crystal discharge line 25. Further, the treated water after the ions are separated as crystals is discharged from the third treated water line 19.

  The crystal supply device 20 supplies seed crystals determined according to the water to be treated and the concentrated water. Specifically, it is the same crystal as the crystal obtained by the reaction in the reaction vessel 18. For example, when the water to be treated contains phosphate ions and the concentrated water contains calcium ions, it is the calcium phosphate salt that is precipitated in the reaction tank 18, so the crystal supply device 20 supplies the calcium phosphate salt as a seed crystal. . In addition, when the water to be treated contains phosphate ions and magnesium ions are contained in the concentrated water, what is precipitated in the reaction tank 18 is a magnesium phosphate salt, so that the crystal supply device 20 has magnesium phosphate as a seed crystal. Supply salt.

  The reaction assistant supply device 22 supplies a reaction assistant according to the pH value of the mixture of the water to be treated and the concentrated water in order to promote the reaction between the anion in the water to be treated and the cation in the concentrated water. For example, the reaction aid supply device 22 supplies, as a reaction aid, a regulator such as an acid or an alkali that is adjusted so that the pH value of the water to be treated and the concentrated water becomes an optimum pH value for crystallization. . Alternatively, the reaction assistant supply device 22 supplies ion-containing water that is adjusted so that the mixed water satisfies the solubility product for exceeding the supersaturation degree necessary for crystallization as a reaction assistant.

  For example, when crystallizing ammonium magnesium phosphate from phosphoric acid-containing wastewater that is ion-containing water, ammonium ions can be supplied as the ion-containing water of the reaction aid. In addition to using ammonium ions provided as chemicals, ammonium ions may use sewage and human waste containing ammonium ions, and wastewater from food processing plants. Using such wastewater, chemicals are used. Compared to the case, the cost required for the medicine can be reduced.

  As described above, in the water treatment device 1a according to the first embodiment, chemicals are obtained by using cations contained in the concentrated water of seawater obtained by desalination for the recovery of anions contained in the ion-containing water. This can reduce the time and cost of obtaining. Moreover, in the water treatment apparatus 1a, it is possible to prevent contamination of ions collected by using seawater concentrated water instead of chemicals, and to collect high-purity ions. Recycling can be realized.

  Furthermore, in the water treatment apparatus 1a, when anions are collected using the concentrated water of seawater that has been desalinated by the second filtration membrane 15 after the solid matter has been removed by the first filtration membrane 12, The concentrated solution of seawater to be used does not contain solid matter that becomes impurities, and it is possible to collect ions of higher purity.

  In addition, when ammonium phosphate contained in the wastewater is used as a reaction aid as a reaction aid, and phosphate ions contained in the ion-containing water are reacted with magnesium ions contained in the concentrated water of seawater to recover magnesium phosphate. The magnesium magnesium phosphate, which is an essential element for plant growth, can be recovered. In such a case, not only the phosphate ions contained in the ion-containing water, but also ammonium ions in the waste water and magnesium ions in the seawater can be used as fertilizers. Realize the generation.

Second Embodiment
As shown in FIG. 2, the water treatment device 1 b according to the second embodiment is compared with the water treatment device 1 a described above with reference to FIG. A drainage line 27, a fourth treated water line 28, a desorbent supply device 29, and a desorbent line 30 are provided, and the reaction tank 18 is different in that treated water is fed from the adsorbent reactor 26. Each line 19, 27, 28 and 30 is provided with valves 191, 271, 281 and 301, respectively.

  The adsorbent reactor 26 is supplied with ion-containing water (ion-containing wastewater or concentrated water of ion-containing wastewater) containing an anionic component that is a treatment target of the water treatment apparatus 1b through the drainage line 27. The adsorbent reactor 26 includes an adsorbent (not shown) that adsorbs ions contained in the ion-containing water. Therefore, when ion-containing water is supplied via the drainage line 27 when the valve 271 is in the open state, ions contained in the ion-containing water are adsorbed by the adsorbent.

  The adsorbent used in the adsorbent reactor 26 is desirably an adsorbent that can selectively and efficiently remove and separate target ionic components and can be used repeatedly. For example, as an adsorbent that adsorbs phosphate ions, a nitrogen-containing compound having an amino group at one end of a molecular structure as described in Patent Document 2, a carrier carrying the nitrogen-containing compound, and the nitrogen-containing compound An adsorbent having at least one metal ion selected from the group consisting of zinc ion, copper ion, iron ion and zircoium ion, etc., immobilized on the substrate can be used.

  The waste water after the ions in the ion-containing waste water are adsorbed by the adsorbent is discharged from the adsorbent reactor 26 via the fourth treated water line 28 when the valve 281 is open.

  The desorbent supply device 29 is configured so that when the amount of ions adsorbed by the adsorbent in the adsorbent reactor 26 decreases and the valve 281 is closed and the valve 301 is opened, the adsorbent is passed through the desorbent line 30. A desorbent is supplied to the reactor 26 to desorb ions adsorbed from the adsorbent. For example, the desorbing agent that desorbs ions from the adsorbent described in Patent Document 2 is selected from alkali metal hydroxides such as sodium hydroxide, pH adjusting agents such as hydrochloric acid, and salts such as sodium chloride. Or it can be mixed and used.

  The lower the flow rate of the desorbed liquid with respect to the adsorbent-filled deposition of the adsorbent reactor 26, the higher the concentration of the ion-containing water, which is the water to be treated, can be supplied to the reaction tank 18, and the more efficient Crystal formation can be realized. Therefore, it is desirable that the desorbing agent supply device 29 supplies the desorbing agent at a liquid passing speed that allows sufficient desorption when the liquid passing rate of the desorbing agent is low (the flow rate is small). Moreover, it is desirable to select the desorption liquid supplied by the desorption agent supply device 29 so as to have a component and concentration that have a small influence on the crystal formation in the reaction tank 18.

  As described above, in the water treatment apparatus 1b according to the second embodiment, the cations contained in the concentrated water of seawater obtained by desalination are used to recover the anions contained in the ion-containing water. This can reduce the time and cost of obtaining. Moreover, in the water treatment apparatus 1b, it is possible to prevent the mixing of chemicals into ions collected by using concentrated seawater instead of chemicals, and to collect high-purity ions. Recycling can be realized.

  Furthermore, in the water treatment apparatus 1b, when the anions are collected using the concentrated water of seawater desalinated by the second filtration membrane 15 after the solid matter is removed by the first filtration membrane 12, as the cation-containing water, The concentrated solution of seawater to be used does not contain solid matter that becomes impurities, and it is possible to collect ions of higher purity.

  In the water treatment apparatus 1b, the concentration of anions in the water to be treated is high in order to treat the concentrated water of anions obtained using the ion adsorbent in the adsorbent reactor 26 as the water to be treated. While the reaction tank 18 can be reduced in size, the purity of the crystallized ion can be improved by suppressing the inclusion of substances other than anions in the water to be treated.

<Modification>
In the example described above with reference to FIGS. 1 and 2, the second filtration membrane 15 and the reaction tank 18 are connected by the concentrated water line 17, and the concentrated seawater obtained by the second filtration membrane 15 is the concentrated water line 17. The water is fed directly from the second filtration membrane 15 to the reaction tank 18 via the. However, the supply of the concentrated water to the reaction tank 18 is not limited to this.

  For example, a concentrated water storage tank is provided between the second filtration membrane 15 and the reaction tank 18, and the concentrated water obtained in the second filtration membrane 15 is temporarily stored in this storage tank, and then the amount of treatment in the reaction tank 18 is increased. Accordingly, water may be sent from the water storage tank to the reaction tank 18. Thus, even if the amount of concentrated water obtained in the second filtration membrane 15 and the amount of concentrated water to be treated in the reaction tank 18 are different, it is possible to temporarily store water in the water storage tank. it can.

  In addition, for example, when the second filtration membrane 15 and the reaction tank 18 are in a positional relationship that is difficult to connect with the concentrated water line 17, the seawater concentrated water obtained by the second filtration membrane 15 is transported by a tank truck or the like. You may transport to the place where the reaction tank 18 is installed using. Thus, by using the transportation means, there is no restriction on the installation position of the reaction tank 18.

  Although the embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, rewrites, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1a, 1b ... Water treatment apparatus 10 ... Desalination means 11 ... Seawater line 12 ... 1st filtration membrane 13 ... 1st treatment water line 14 ... Solid matter line 15 ... 2nd filtration membrane 16 ... 2nd treatment water line 17 ... Concentration Water line 18 ... Reaction tank 19 ... Water to be treated 20 ... Crystal supply device 21 ... Crystal supply line 22 ... Reaction aid supply device 23 ... Reaction aid line 24 ... Third treated water line 25 ... Crystal line 26 ... Adsorbent Reactor 27 ... Drain line 28 ... Fourth treated water line 29 ... Desorbent supply device 30 ... Desorbent line 191,271,281,301 ... Valve

Claims (7)

A water treatment device for recovering ions from ion-containing water,
A desalination means having a first filtration membrane that separates solids contained in seawater, and a second filtration membrane that further separates salt from the separated seawater to obtain concentrated water;
A concentrated water line to which the concentrated seawater obtained when desalinating the seawater obtained by the second filtration membrane of the desalination means is supplied;
A treated water line in which ion-containing water is supplied as treated water;
The anion contained in the for-treatment water supplied via the to-be-treated water line reacts with the cation derived from seawater contained in the concentrated water supplied via the concentrated water line to the to-be-treated water. A reaction vessel for crystallizing the contained ions;
A crystal discharge line for discharging the generated crystals from the reaction vessel;
A water treatment apparatus comprising:   The water treatment device according to claim 1, wherein ions contained in the ion-containing water are phosphate ions.   The water treatment device according to claim 1, wherein the ions contained in the ion-containing water are sulfate ions or fluoride ions.   The water treatment apparatus according to any one of claims 1 to 3, wherein the water to be treated supplied from the water line to be treated is derived from sewage.   The water treatment apparatus according to claim 2, wherein the crystal generated in the reaction tank is a calcium phosphate salt or a magnesium phosphate salt.   The water treatment apparatus according to any one of claims 1 to 5, further comprising a reaction aid supply device that supplies a reaction aid that promotes the reaction between anions and cations to the reaction tank. A concentrated water storage tank connected to the concentrated water line and storing the concentrated water supplied via the concentrated water line;
The water treatment apparatus according to any one of claims 1 to 6, wherein the reaction tank is supplied with the concentrated water stored in the concentrated water storage tank.

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