JP7237714B2 - water treatment equipment - Google Patents

Description

Embodiments of the present invention relate to water treatment devices.

In recent years, laws and regulations for realizing healthy water circulation have been strengthened. ZLD (Zero Liquid Discharge) reduces the risk of water pollution and regenerates and reuses wastewater by regenerating and using water within the factory, and further reduces the wastewater discharged from the factory to zero. The concept is to conserve the water environment by

For the wastewater concentration treatment for ZLD, it is necessary to pretreat the water to be treated that is introduced into the reverse osmosis (RO) membrane process. In the pretreatment for the RO membrane process, for example, the water to be treated is softened with a weakly acidic ion exchange resin, and an acid is added to the softened water to adjust the pH to acidic. Then, it is assumed that the water to be treated that has been acidified in pH is decarboxylated, and alkali is added to the decarboxylated water to be treated to adjust the pH to alkaline.

By the way, when the weakly acidic ion-exchange resin is used in water softening treatment, it is conditioned to be alkaline by adding a conditioning agent after acid regeneration, for example. When the water to be treated is passed through the weakly acidic ion exchange resin immediately after conditioning, alkali metal ions derived from the conditioning agent are released. Since the pH of the treated water after the softening treatment is biased toward the alkaline side, as described in the above pretreatment, the pH of the treated water after the softening treatment is adjusted to be acidic, and after the decarboxylation treatment When it is attempted to adjust the pH of the treated water to be alkaline, there is a problem that the range of pH adjustment is widened and the consumption of the chemical solution is increased.

U.S. Pat. No. 5,925,255 U.S. Pat. No. 6,537,456

It is therefore an object of the present invention to provide a water treatment apparatus capable of reducing the amount of chemical added.

According to an embodiment, the water treatment device is a water treatment device for ZLD (Zero Liquid Discharge), comprising a decarboxylation device, a first regulator, a first water softener, a second regulator, and reverse osmosis. Equipped with a membrane device. The decarboxylation device removes dissolved carbonic acid components in the water to be treated that contain carbonic acid species ions . The first adjusting section adds an alkali to the water from which the dissolved carbonic acid component has been removed, and adjusts the water to be substantially neutral. The first water softening device softens the water to be treated that has been adjusted to be substantially neutral. The second adjustment unit adds an alkali to the softened water to be treated to adjust the water to be treated to be alkaline. The reverse osmosis membrane device separates the alkalinity-adjusted water to be treated into concentrated water and permeated water by means of a reverse osmosis membrane.

FIG. 1 is a block diagram showing the functional configuration of the water treatment device according to the first embodiment. FIG. 2 is a block diagram showing the functional configuration of the water treatment device according to the second embodiment. FIG. 3 is a block diagram showing a modification of the functional configuration of the water treatment device according to the second embodiment.

Embodiments will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing an example of the functional configuration of a water treatment device 1 according to the first embodiment. A water treatment device 1 shown in FIG.

The decarboxylation device 10 removes the dissolved carbonic acid component in the supplied water to be treated. The decarboxylation device 10 is selected, for example, from technologies having a function of removing carbonate species ions in the water to be treated. For example, the decarboxylation device 10 is implemented using a water sprinkling gas-liquid contact, a degassing membrane, or the like. If the water to be treated supplied to the decarboxylation device 10 is pH-adjusted to be acidic, dissolved carbonic acid components can be effectively removed. The treated water from which the dissolved carbonic acid component has been removed by the decarboxylation device 10 is discharged to the water flow line 11 as the water to be treated.

In this embodiment, the water to be treated is, for example, waste water containing carbonate species ions and hardness components. Wastewater containing carbonate species ions includes, for example, wastewater subjected to aerobic treatment, wastewater subjected to anaerobic treatment, wastewater subjected to solid-liquid separation treatment such as neutral to alkaline coagulation sedimentation or flotation, Alternatively, wastewater or the like that has undergone a hardness removal treatment by adding sodium carbonate or the like can be used. In addition, waste water that has undergone any combination of these treatments is also included in waste water containing carbonate species ions.

The first pH adjuster 50 adds alkali to the water to be treated supplied to the water softener 20 through the water flow line 11 . The first pH adjustment unit 50 includes, for example, a pump, and pumps alkali such as sodium hydroxide to the water flow line 11 by the pump. The water to be treated is neutralized by the addition of alkali. More specifically, for example, the pH of the water to be treated discharged from the decarboxylation device 10 is about 5.5. The first pH adjusting unit 50 adds alkali to the water flow line 11 so that the water to be treated has a pH of about 7 to 7.5, for example.

The water softening device 20 softens the water to be treated supplied from the water flow line 11 . That is, the water softening device 20 replaces the hardness components contained in the water from which the dissolved carbonic acid component has been removed by the decarboxylation device 10 with sodium ions to produce soft water. Soft water is produced by substituting sodium ions for hardness components contained in water from which dissolved carbonic acid components have been removed by the decarboxylation device 10 . The water softener 20 is realized using, for example, a weakly acidic cation exchange resin. Weakly acidic ion exchange resins are, for example, acid-regenerated and then conditioned to be alkaline by adding a conditioning agent. The treated water softened by the water softening device 20 is discharged to the water flow line 21 as water to be treated. Note that only one water softening device 20 is shown in the water treatment device 1 shown in FIG. However, in practical use, a plurality of water softening apparatuses 20 are provided, and operations such as chemical regeneration and the flow of water to be treated are switched for operation.

The second pH adjuster 60 adds alkali to the water to be treated supplied to the booster pump 30 through the water flow line 21 . The second pH adjustment unit 60 includes, for example, a pump, and pumps alkali such as sodium hydroxide to the water flow line 21 by the pump. The addition of alkali makes the water to be treated alkaline. More specifically, the pH of the water to be treated discharged from the water softening device 20 is, for example, about 8 to 9 immediately after the alkaline conditioning of the weakly acidic cation exchange resin. The second pH adjusting unit 60 adds alkali to the water flow line 21 so that the water to be treated has a pH of about 9 to 10, for example. The water to be treated to which the alkali has been added by the second pH adjusting unit 60 is boosted to a preset pressure by the boosting pump 30 and supplied to the RO membrane concentrator 40 . Note that the preset pressure is, for example, a pressure that is at least higher than the osmotic pressure.

The RO membrane concentration device 40 is an example of a reverse osmosis membrane device that separates the water to be treated, which is supplied after being pressurized to a high pressure, into permeated water from which dissolved salts have been removed and concentrated water from which dissolved salts have been concentrated. be. The RO membrane concentrator 40 is operated, for example, in an alkaline environment. The RO membrane concentrator 40 includes, for example, a pressure vessel 41 and a reverse osmosis membrane element 42 installed within the pressure vessel 41 . The reverse osmosis membrane element 42 has a reverse osmosis membrane 421 . As the reverse osmosis membrane 421, for example, a spiral or hollow fiber membrane is used. The RO membrane concentrator 40 sends the high-pressure concentrated water separated by the reverse osmosis membrane 421 to the downstream stage and discharges the permeated water separated by the reverse osmosis membrane 421 .

As will be described later, the water treatment apparatus 1 according to the present embodiment can appropriately remove hardness components and carbonate species ions by pretreatment, so that precipitation of carbonate derived from hardness can be suppressed in the RO membrane concentrator 40. becomes possible. Therefore, the environment is suitable for operating the RO membrane concentrator 40 in an alkaline environment to suppress the generation of silica scale and the like.

Although FIG. 1 shows that one reverse osmosis membrane element 42 is installed in the pressure vessel 41, the present invention is not limited to this. For example, a plurality of reverse osmosis membrane elements 42 may be installed in the pressure vessel 41 . Moreover, the RO membrane concentrator 40 may include a plurality of pressure vessels 41 . At this time, for example, the RO membrane concentrator 40 includes a plurality of pressure vessels 41 having reverse osmosis membrane elements 42 arranged in a multistage configuration, a multisystem configuration, a tree configuration, or the like.

Further, the RO membrane concentrator 40 may be provided with a power recovery device depending on the operating pressure and the scale of the device. The power recovery device is a device that recovers pressure energy from high-pressure concentrated water sent from the RO membrane concentrator 40 .

In addition, the RO membrane concentrator 40 may be provided with an introduction route for a scale inhibitor, a slime inhibitor having an oxidation-reduction function, a cleaning agent, and/or cleaning water, depending on the quality of the water to be treated. At this time, for example, a water quality meter is arranged at the inlet of the RO membrane concentrator 40 . By operating the introduction route based on the water quality measured by this water quality meter, the addition operation of the scale inhibitor and the slime inhibitor and the cleaning operation of the RO membrane concentrator 40 are carried out.

Also, the salt-concentrated water derived from the concentrated water separated by the RO membrane concentrating device 40 may be used as a regenerating liquid for the weakly acidic cation exchange resin of the water softening device 20 . This makes it possible to reduce the amount of regenerating liquid used.

As described above, in the first embodiment, the water treatment device 1 neutralizes the water to be treated by adding alkali to the water to be treated after the decarbonation treatment in the decarbonation device 10 . The water treatment device 1 softens the neutralized water to be treated with the weakly acidic ion exchange resin of the water softening device 20, and then adds alkali to the water to make the water suitable for RO membrane treatment. The pH is adjusted to the desired value. As a result, it becomes possible to effectively utilize the ability to manipulate the pH in the alkaline direction by the resin discharged components contained in the liquid that has passed through the weakly acidic ion exchange resin of the water softening device 20 .

By the way, the water to be treated that is supplied to the water treatment apparatus 1 according to the present embodiment contains alkaline earth metal ions such as magnesium ions and/or calcium ions in addition to carbonate species ions. When such water to be treated is introduced into the weakly acidic cation exchange resin of the water softening device 20 before being introduced into the decarboxylation device 10, alkaline earth carbonates and hydroxide salts are formed in the resin tower. These salts formed and formed can accumulate inside the resin tower. The weakly acidic cation exchange resin gradually lowers the pH of the discharged liquid as the water softening time elapses. When the pH drops, carbon dioxide gas is generated from a part of the carbonates among the sedimentary salts deposited in the resin tower. Due to the generation of carbon dioxide gas, air bubbles accumulate inside the resin tower, causing layer rise due to air bubbles in the resin packed bed or a decrease in packed bed density. Uniformity may not be maintained.

On the other hand, in the water treatment apparatus 1 according to the first embodiment, the water to be treated from which the carbonate species ion component has been removed by the decarboxylation apparatus 10 is introduced into the water softening apparatus 20 . Therefore, the precipitation of the carbonate component and the deposition and accumulation of the precipitated carbonate component in an alkaline-conditioned weakly acidic cation exchange resin environment are suppressed.

In addition, in the water treatment apparatus 1 according to the first embodiment, the water to be treated from which carbonate species ion components have been removed is softened by the water softening device 20. Therefore, for various types of waste water containing carbonate species ion components, After removing scale factors such as appropriate hardness removal and carbonation removal, it becomes possible to concentrate the waste water with an RO membrane in an alkaline environment. That is, the water treatment apparatus 1 can appropriately operate the waste water concentration operation for various waste water containing carbonate species ions.

(Second embodiment)
FIG. 2 is a block diagram showing an example of the functional configuration of the water treatment device 1a according to the second embodiment. The water treatment device 1a shown in FIG. 2 includes a filtration device 70, a first water softening device 80, a decarbonation device 10a, a second water softening device 20a, boosting pumps 30a and 90, a first RO membrane concentrator 40a, and a second RO membrane. It includes a concentrator 100, a first pH adjustment section 110, a second pH adjustment section 50a, and a third pH adjustment section 60a.

The filtering device 70 filters the supplied water to be treated. The filtration device 70 is realized using membrane separation technology such as a microfiltration (MF) membrane, an ultrafiltration (UF) membrane, and a MBR (Membrane Bioreactor) method, for example. In addition, a sand filter device may be provided upstream of the filter device 70 .

The first water softening device 80 softens the water filtered by the filtering device 70 . That is, the first water softening device 80 replaces hardness components contained in the water filtered by the filtering device 70 with cations to produce soft water. The first water softener 80 is implemented using, for example, a weakly acidic cation exchange resin or a strongly acidic cation exchange resin. The treated water softened by the first water softener 80 is discharged to the water flow line 81 as water to be treated.

When a weakly acidic cation exchange resin is used in the first water softener 80, this weakly acidic cation exchange resin is, for example, the same media (beads) as the weakly acidic cation exchange resin used in the second water softener 20a, In addition, it may be housed in a resin tower having the same structure as the resin or the like provided as the second water softening device 20a. By constructing the first water softening device 80 and the second water softening device 20a in this way and providing a switching means for switching the flow line of the water to be treated, the first water softening device 80 and the second water softening device 20a can be operated in a merry-go-round format.

More specifically, for example, first to third resin towers are provided, two of which are assigned as the first water softener 80 and the second water softener 20a, respectively, and one is used for chemical regeneration. Operate to wait. At this time, for example, the first resin tower is used as the second water softener 20a, the second resin tower is used as the first water softener 80, and the chemical solution is regenerated in the third resin tower. The third resin tower is used as the second water softener 20a, the first resin tower is used as the first water softener 80, the second water flow line for chemical regeneration of the second resin tower, and the second resin tower It is used as the second water softener 20a, the third resin tower is used as the first water softener 80, and a third water flow line is provided to regenerate the chemical solution in the first resin tower. Then, the connection is switched in the order of the first water line, the second water line, and the third water line by the switching means.

In addition, when a strongly acidic cation exchange resin is used in the first water softener 80, a plurality of resin towers are provided as the first water softener 80, and switching between operations such as chemical regeneration and passage of the water to be treated is performed. operated by The type and structure of the ion exchange resin of the first water softening device 80 are selected according to the concentration of ion components in the water to be treated.

The first pH adjuster 110 adds an acid to the water to be treated that is supplied to the decarboxylation device 10a through the water passage line 81 . The first pH adjusting unit 110 includes, for example, a pump, and pumps an acid such as hydrochloric acid to the water flow line 81 by the pump. The addition of the acid acidifies the water to be treated and accelerates the decarbonation treatment in the decarbonation device 10a.

The decarboxylation device 10a operates similarly to the decarboxylation device 10 in the first embodiment. That is, the decarbonation device 10 a removes the dissolved carbonic acid component from the water to be treated which is softened by the first water softening device 80 and supplied from the water flow line 81 . The decarbonation device 10a is selected, for example, from technologies having a function of removing carbonate species ions in the water to be treated. The treated water from which the dissolved carbonic acid component has been removed by the decarboxylation device 10 is discharged to the water flow line 11a as the water to be treated.

The second pH adjuster 50a operates in the same manner as the first pH adjuster 50 in the first embodiment. That is, the second pH adjuster 50a adds alkali to the water to be treated that is supplied to the second water softener 20a through the water flow line 11a. The second pH adjustment unit 50a has, for example, a pump, and pumps alkali to the water flow line 11a. The water to be treated is neutralized by the addition of alkali.

The second water softener 20a operates similarly to the water softener 20 in the first embodiment. That is, the second water softener 20a produces soft water by substituting sodium ions for the hardness components contained in the water to be treated which is supplied from the water flow line 11a after the dissolved carbonic acid components have been removed by the decarboxylation device 10a. The second water softener 20a is implemented using, for example, a weakly acidic cation exchange resin. The treated water that has been softened by the second water softener 20a is discharged to the water flow line 21a as water to be treated. If the first water softener 80 does not have the same structure as the second water softener 20a, that is, if the first water softener 80 and the second water softener 20a cannot be operated in a merry-go-round fashion, the second A plurality of water softening devices 20a are provided, and are operated by switching between operations such as chemical regeneration and passing water to be treated.

The third pH adjuster 60a operates in the same manner as the second pH adjuster 60 in the first embodiment. That is, the third pH adjuster 60a adds alkali to the water to be treated that is supplied to the booster pump 30a through the water flow line 21a. The third pH adjusting section 60a includes, for example, a pump, and pumps alkali to the water flow line 21a. The addition of alkali makes the water to be treated alkaline. The water to be treated to which the alkali has been added by the third pH adjusting section 60a is boosted to a preset pressure by the boosting pump 30a and supplied to the first RO membrane concentrator 40a.

The first RO membrane concentrator 40a operates in the same manner as the first RO membrane concentrator 40a in the first embodiment. That is, the first RO membrane concentrator 40a is operated in an alkaline state, and the water to be treated, which is supplied after being pressurized to a high pressure, is separated into permeated water from which dissolved salts have been removed and concentrated water in which dissolved salts have been concentrated. . The first RO membrane concentrator 40a sends high-pressure concentrated water separated by the reverse osmosis membrane 421a to a subsequent stage, and discharges permeated water separated by the reverse osmosis membrane 421a. The concentrated water sent from the first RO membrane concentrator 40 a is boosted to a preset pressure by the boost pump 90 and supplied to the second RO membrane concentrator 100 . If the concentrated water sent from the first RO membrane concentrator 40a has, for example, a pressure higher than at least the osmotic pressure, the boost pump 90 need not be provided.

The second RO membrane concentrator 100 separates the supplied concentrated water pressurized to a high pressure into permeated water from which dissolved salts have been removed and concentrated water from which dissolved salts are further concentrated. The second RO membrane concentrator 100 is operated, for example, in an alkaline environment. The second RO membrane concentrator 100 includes, for example, a pressure vessel 101 and a reverse osmosis membrane element 102 installed within the pressure vessel 101 . The reverse osmosis membrane element 102 has a reverse osmosis membrane 1021 . In addition, although FIG. 2 shows that one reverse osmosis membrane element 102 is installed in the pressure vessel 101, it is not limited to this. For example, a plurality of reverse osmosis membrane elements 102 may be installed in the pressure vessel 101 . Also, the second RO membrane concentrator 100 may include a plurality of pressure vessels 101 . At this time, for example, the second RO membrane concentrator 100 includes a plurality of pressure vessels 101 having reverse osmosis membrane elements 102 arranged in a multistage configuration, a multisystem configuration, a tree configuration, or the like.

The second RO membrane concentrator 100 sends the high-pressure concentrated water separated by the reverse osmosis membrane 1021 to the downstream stage and discharges the permeated water separated by the reverse osmosis membrane 1021 . In addition, the second RO membrane concentrator 100 may form a concentrated liquid internal circulation. That is, part of the concentrated water sent from the second RO membrane concentrator 100 may be circulated and supplied to the second RO membrane concentrator 100 . Further, the second RO membrane concentrator 100 may supply the permeated water separated by the reverse osmosis membrane 1021 to the water flow line 21a.

As described above, in the second embodiment, the water treatment device 1a performs decarbonation treatment in the decarbonation device 10a after the water softening treatment in the first water softening device 80, and adds alkali to the water to be treated. This neutralizes the water to be treated. The water treatment device 1a softens the neutralized water to be treated with the weakly acidic ion exchange resin of the second water softening device 20a, and then adds alkali to the water to be treated with an RO membrane. I am trying to adjust to a pH suitable for. As a result, it becomes possible to effectively utilize the ability to manipulate the pH in the alkaline direction by the resin discharged components contained in the liquid that has passed through the weakly acidic ion exchange resin of the second water softener 20a.

In addition, precipitation of the carbonate component in an alkaline-conditioned weakly acidic cation exchange resin environment, and deposition and accumulation of the precipitated carbonate component are suppressed.

In addition, in the water treatment apparatus 1a according to the second embodiment, the water to be treated from which the carbonate species ion components have been removed is softened by the weakly acidic cation exchange resin of the second water softening device 20a, so that the carbonate species ion components After removing scale factors such as appropriate hardness removal and carbonation removal, it becomes possible to concentrate the wastewater with an alkaline RO membrane. That is, the water treatment apparatus 1a can appropriately operate the waste water concentration operation for various waste water containing carbonate species ions.

Moreover, in the second embodiment, the water treatment device 1a can apply a strongly acidic cation exchange resin to the first water softening device 80, for example. By applying a strongly acidic cation exchange resin to the first water softening device 80, it is possible to remove hardness while suppressing an increase in pH of the water source to be treated in the decarboxylation device 10a. This makes it possible to reduce the hardness load on the second water softener 20a while reducing the amount of acid supplied by the first pH adjuster 110 . That is, it is possible to suppress the amount of chemicals consumed and proceed with hardness removal.

Further, in the second embodiment, the water treatment device 1a can apply a weakly acidic cation exchange resin to the first water softening device 80, for example. The weakly acidic cation exchange resin is applied to the first water softener 80, and the type of the weakly acidic cation exchange resin and the structure of the resin tower are matched between the first water softener 80 and the second water softener 20a. Therefore, the first water softener 80 and the second water softener 20a can be used in a merry-go-round style. As a result, the resin tower whose water softening efficiency has decreased due to its use as the second water softener 20 a can be switched to be used as the first water softener 80 . That is, it becomes possible to effectively utilize the resin tower.

(Modification)
FIG. 3 is a block diagram showing a modification of the functional configuration of the water treatment device 1b according to the second embodiment. The water treatment apparatus 1b shown in FIG. 3 is provided with an evaporative concentration apparatus 120 in the latter stage of the second RO membrane concentrator 100 in contrast to the water treatment apparatus 1a shown in FIG.

The evaporative concentration device 120 is an example of a heat treatment device that performs a heat treatment process on a concentrated liquid containing water-soluble organic matter, and is, for example, a device that performs evaporative concentration. The evaporative concentration device 120 evaporates water derived from the concentrated water supplied from the second RO membrane concentrator 100 to generate an evaporation residue and evaporated water. The evaporative concentration device 120 is realized by, for example, a configuration using an evaporator, a configuration using heating steam, a configuration using an existing system such as a spray dryer, or the like. As the evaporator, for example, a single effect can and a multi-effect can may be used. The configuration using heating steam includes, for example, a TVR (Thermo-Vapor Recompression) type, an MVR (Mechanical Vapor Recompression) type, and a configuration using a heat pump or the like. Note that the evaporative concentration device 120 may have additional configurations of a centrifugal separator and a solid-liquid separator depending on the generation of evaporation residue. Further, in order to promote evaporation and concentration, a mechanism for adding chemicals such as an antifoaming agent and an anti-scaling agent may be provided.

By arranging the first RO membrane concentrating device 40a and the second RO membrane concentrating device 100 in multiple stages before the evaporative concentration device 120, the evaporative concentration process and wastewater zero can be achieved while responding to fluctuations in the amount and quality of the water to be treated. It becomes possible to

The water treatment apparatuses 1a and 1b may further have an oxidation treatment tank, a coagulation treatment tank, a biological treatment tank, or a combination of at least two or more of these before the filtration device 70. FIG. When the membrane separation activated sludge method or the like is introduced in the biological treatment tank, at least part of the filtration device 70 may be included in the biological treatment tank.

According to at least one embodiment described above, the water treatment equipment 1, 1a, 1b can reduce the amount of chemical added. In addition, by suppressing the deposition and accumulation of carbonate components, the pressure loss due to the deposited solid content, the accumulation of bubbles in the weakly acidic cation exchange resin layer due to redissolution of the deposited solid content, and the resin layer accompanying the growth of the generated bubbles It is possible to solve the problem of maintaining soundness when operating an ion exchange resin process, such as drift of the flow and/or lack of homogenous packing of the resin bed.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

Reference Signs List 1, 1a, 1b Water treatment equipment 10, 10a Decarboxylation equipment 11, 11a Water flow line 20 Water softener 20a Second water softener 21, 21a Water flow lines 30, 30a Boosting pump 40 RO membrane concentrator 40a First RO membrane concentrator 41 Pressure vessel 42 Reverse osmosis membrane element 421, 421a Reverse osmosis membrane 50 First pH adjustment unit 50a Second pH adjustment unit 60 Second pH adjustment unit 60a Third pH Adjustment unit 70 Filtration device 80 First water softening device 81 Water flow line 90 Boosting pump 100 Second RO membrane concentration device 101 Pressure vessel 102 Reverse osmosis membrane element 1021 Reverse osmosis membrane 110 First pH adjustment unit 120 Evaporative concentration device

Claims (13)

A water treatment device for ZLD (Zero Liquid Discharge),
a decarbonation device for removing dissolved carbonic acid components in the water to be treated containing carbonic acid species ions ;
a first adjustment unit for adding an alkali to the water from which the dissolved carbonic acid component has been removed to adjust the water to be treated to be substantially neutral;
a first water softening device for softening the water to be treated which has been adjusted to be substantially neutral;
a second adjustment unit that adds an alkali to the softened water to be treated to adjust the water to be treated to be alkaline;
A water treatment apparatus comprising a reverse osmosis membrane device for separating the alkaline-adjusted water to be treated into concentrated water and permeated water by means of a reverse osmosis membrane. 2. The water treatment apparatus according to claim 1 , wherein said first water softener softens the water to be treated with a weakly acidic cation exchange resin. a filtering device for filtering the water to be treated;
a second water softening device for softening the filtered water to be treated;
3. A third adjusting unit that adjusts the water softened by the second water softener to acidity and supplies the acidified water to the decarboxylation device. Water treatment equipment as described. 4. The water treatment apparatus according to claim 3, wherein the second water softener softens the water to be treated with a weakly acidic cation exchange resin. first and second resin towers of identical construction containing first and second weakly acidic cation exchange resins of the same type, respectively;
a first water flow line using the first resin tower as the first water softener and using the second resin tower as the second water softener;
a second water flow line using the second resin tower as the first water softener and using the first resin tower as the second water softener;
4. The water treatment apparatus according to claim 3, further comprising switching means for switching between said first water line and said second water line. first to third resin towers having the same structure, which accommodate first to third weakly acidic cation exchange resins of the same type, respectively;
a first water flow line using the first resin tower as the first water softener and using the second resin tower as the second water softener;
a second water flow line using the third resin tower as the first water softener and using the first resin tower as the second water softener;
a third water flow line using the second resin tower as the first water softener and using the third resin tower as the second water softener;
4. The water treatment apparatus according to claim 3, further comprising switching means for switching connections in the order of the first water line, the second water line, and the third water line. 4. The water treatment apparatus according to claim 3, wherein the second water softener softens the water to be treated with a strongly acidic cation exchange resin. The second water softening device softens the water to be treated with a strongly acidic cation exchange resin,
4. The water treatment apparatus according to claim 3, wherein a plurality of said second water softeners are provided. 9. The water treatment apparatus according to any one of claims 1 to 8, wherein said reverse osmosis membrane apparatus is operated in alkaline conditions. 10. The water treatment apparatus according to any one of claims 1 to 9, further comprising an evaporative concentration apparatus that heats the concentrated water separated by the reverse osmosis membrane apparatus to evaporate water contained in the concentrated water. 10. The water treatment apparatus according to any one of claims 1 to 9, further comprising a second reverse osmosis membrane device that separates the separated concentrated water into a second concentrated water and a second permeated water by means of a reverse osmosis membrane. 12. The water treatment apparatus according to claim 11, further comprising an evaporative concentration apparatus that heats the second concentrated water separated by the second reverse osmosis membrane apparatus to evaporate water contained in the second concentrated water. 13. The water treatment device according to any one of claims 1 to 12, wherein the concentrated water separated by the reverse osmosis membrane device is used as a regeneration liquid for regenerating the first water softener.

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