JP2006187708A - Waste water recovery method and waste water recovery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste water recovery method and a waste water recovery device, wherein the reduction of space can be attained, or further, waste water can be dramatically reduced by dispensing with the installation of a conventional large scale waste water recovery device. <P>SOLUTION: Ultrapure water obtained in an ultrapure water production apparatus 20 is fed to each use point 14. Among the water to be exhausted from each use point 14, the waste water comprising inorganic ion components in the concentration of 0.01 to 1,000 mg/l is fed to an electric deionization apparatus 15, so as to perform deionization treatment, and the treated water in the electric deionization apparatus 15 is returned to the ultrapure water production apparatus 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wastewater recovery method in which wastewater after use of pure water or ultrapure water in the semiconductor manufacturing field, electric power field, pharmaceutical manufacturing, and other industries is treated with an electrodeionization device for reuse. It relates to a wastewater recovery device.

  Collecting and reusing wastewater such as industrial wastewater not only saves water resources but also helps prevent environmental pollution, and wastewater collection and reuse is an important technical issue. . In facilities that use pure water and ultrapure water such as factories and research facilities, industrial wastewater discharged at each use point (use point) is not collected and reused for each use point, but roughly. The wastewater classified into inorganic and organic is sent to the wastewater treatment facility in a lump and is collected and reused. This is because if wastewater is collected for each use point, a wastewater recovery facility must be installed for each use point, and there is a disadvantage that an installation space is required and costs are required.

  FIG. 6 is a flowchart of a typical wastewater recovery apparatus in a semiconductor manufacturing factory according to the prior art. In the wastewater recovery apparatus 100 of FIG. 6, raw water such as city water and industrial water is pretreated by the pretreatment apparatus 101, and the treated water is supplied to the primary pure water production apparatus 102, and then ultrapure in the subsystem 103. The water is produced, the ultrapure water is used at the use point 104, a part of the water discharged from the use point 104 is supplied to the waste water recovery facility 105, and the water produced from the waste water recovery facility 105 is primary pure. It returns to the water production apparatus 102 and water is reused. The use point 104 is in the clean room 106, and the waste water collection facility 105 is installed outside the clean room.

  The water returned to the wastewater recovery facility 105 is a chemical or mechanical polishing such as a hydrofluoric acid component, an acid or alkali component, an organic component, a polishing component such as silicon powder, or a polishing slurry, silicon or a metal piece. Among water containing system components, it is a diluted waste water having a concentration of 0.001 mg / l to 30%. Wastewater other than these is sent to another wastewater treatment facility, where it is treated and discarded as wastewater.

In this way, among the diluted wastewater classified in a lump, industrial wastewater containing inorganic mixed components, for example, contains acid, alkali, or salts, so deionization treatment should be applied to collect wastewater. Is required. However, the waste water is a mixture of various components, and it is necessary to adopt a treatment method according to the contained components. Conventionally, as a device for treating such waste water, a reverse osmosis membrane device, an ion exchange resin device, and an electrodeionization device are mainly used. On the other hand, JP-A-2001-976 divides a concentration chamber of an electrodialysis apparatus into two chambers by a diaphragm, and feeds and discharges supply water different from the anode-side concentration chamber into and out of the cathode-side concentration chamber. A deionized water production apparatus for producing deionized water by preventing precipitation and accumulation of hardness components in the concentration chamber is disclosed.
JP 2001-976 A (Claim 1, FIG. 1)

  However, reverse osmosis membrane devices and ion exchange resin devices are suitable for treating mixed component-containing wastewater. However, reverse osmosis membrane devices have poor water utilization, require installation and operating costs, and have a large installation space. Necessary. In addition, since the ion exchange resin device requires a chemical regeneration step, the operation efficiency is poor. On the other hand, the electrodeionization apparatus eliminates the above-mentioned drawbacks and can realize low-cost operation with a small installation space. However, the electrodeionization apparatus has poor treatment performance for high ion loads and multivalent ion components, and when the mixed waste water is treated water, sufficient treatment performance cannot be obtained. Moreover, the conventional electrodeionization apparatus has a drawback that the concentration factor cannot be increased to 100 times or more, and the water utilization rate is low. In addition, the concentrated water of the electrodeionization device is evaporated to dryness, but because the ion concentration is low, a large amount of thermal energy is required to separate the solid content of the solute, making the device in the evaporation to dryness process complicated. And the burden of processing operations and operating costs is increased.

  For this reason, the conventional wastewater treatment uses a combination of a plurality of the wastewater recovery devices. For example, industrial wastewater is first passed through a reverse osmosis membrane device, and ions that cannot be removed by the reverse osmosis membrane device are sufficiently removed by an ion exchange resin device or an electric deionization device to obtain demineralized water having a certain water quality. Subsequently, the demineralized water was returned to the primary pure water production system in the production of ultrapure water as recovered water and reused. However, such a waste water recovery apparatus has a problem that the processing cost increases on a large scale and a large installation space is required. In addition, it is conceivable to return to the previous stage in order to reuse the concentrated water of the electrodeionization apparatus, but this causes a problem that the operation operation of the previous stage becomes complicated, and the design and operation process of the apparatus become complicated. . Moreover, the deionized water manufacturing apparatus which divided | segmented the concentration chamber of Unexamined-Japanese-Patent No. 2001-976 into two chambers does not have description of providing the concentrated water circulation system which passes through a concentration chamber. For this reason, although precipitation and accumulation | storage of the hardness component in a concentration chamber are prevented and deionization performance is maintained stably for a long period of time, it does not raise a concentration rate and raise the utilization factor of water.

  Accordingly, an object of the present invention is to provide a wastewater recovery method and wastewater recovery apparatus that can save space or can dramatically reduce wastewater without the need for installing a large-scale wastewater recovery apparatus as in the prior art. It is to provide.

  In such a situation, the present inventors have intensively studied, and as a result, supplied pure water or ultrapure water obtained with pure water or ultrapure water production equipment to each use point and discharged from each use point. Of the wastewater, only a specific wastewater is supplied to the electrodeionization device to perform the deionization treatment, and the treated water of the electrodeionization device is returned to the pure water or ultrapure water production device. It is not necessary to install a large-scale wastewater collection device, and space saving can be achieved. Concentrated wastewater can be drastically reduced by using an electrodeionization device with a concentrated concentrating chamber. As a result, the present inventors have completed the present invention.

  That is, the present invention supplies pure water or ultrapure water obtained with pure water or ultrapure water production equipment to each use point, and out of waste water discharged from each use point, 0.01 to 1000 mg / Waste water containing an inorganic ion component having a concentration of l is supplied to an electrodeionization device to perform deionization treatment, and the treated water of the electrodeionization device is used as a primary pure water production device for the pure water or ultrapure water production device. Alternatively, the present invention provides a wastewater recovery method characterized by being returned to the subsystem.

  Further, the present invention includes a pure water or ultrapure water production apparatus for producing pure water or ultrapure water, each use point using the pure water or ultrapure water, and an electrodeionization apparatus, A first drainage pipe for allowing wastewater containing inorganic ion components having a concentration of 0.01 to 1000 mg / l out of wastewater discharged from a use point to flow into the deionization chamber of the electrodeionization device, and the electrodeionization device The waste water recovery apparatus characterized by including the return piping which returns this treated water to this pure water or an ultrapure water manufacturing apparatus is provided.

According to the present invention, only an electrodeionization device that does not require a large installation space is installed in the vicinity of a use point as a waste water recovery device, and waste water can be recovered and reused for each use point, so a large-scale waste water recovery facility is installed. There is no need to do.
Moreover, the concentration drainage of an electrodeionization apparatus can be drastically reduced by increasing the concentration ratio of the electrodeionization apparatus by 10 ² to 10 ⁶ times, and the water utilization rate of the apparatus alone increases. Since concentrated drainage is extremely small, it is sufficient to install a waste liquid tank with a small capacity, and it is possible to install it in a place such as a clean room where a drainage line cannot be installed.
Since it is not necessary to reuse concentrated water such as returning the concentrated water to the previous stage or further concentrating, the apparatus can be simplified and designed easily.

  A drainage recovery method and drainage recovery apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a flow diagram of the wastewater recovery apparatus of this example. Although it does not restrict | limit especially as a pure water or ultrapure water manufacturing apparatus in this invention, The ultrapure water manufacturing apparatus 20 of this example is the pre-processing apparatus 11, the primary pure water manufacturing apparatus 12, and the secondary pure water manufacturing apparatus 13. Are arranged in this order. The pretreatment device 11 can remove turbidity, fine particles, oxidant, and the like, and includes, for example, one or more devices selected from a microfiltration membrane device, an ultrafiltration membrane device, and an activated carbon device. The primary pure water production apparatus 12 is composed of, for example, one or more selected from a reverse osmosis membrane apparatus, an ion exchange resin apparatus, and an electrodeionization apparatus. The subsystem 13 includes one or more selected from, for example, an ultraviolet oxidation device, a microfiltration membrane device, an ultrafiltration membrane device, an ion exchange resin device, and an electrodeionization device.

  The ultrapure water obtained by the ultrapure water production apparatus 20 is supplied to each use point 14. The use point 14 refers to a point where ultrapure water is used. The use points 14 are usually installed at a plurality of locations in the clean room 16, and processes such as peeling, cleaning, edging and developing of the semiconductor substrate are performed, and ultrapure water is used in each process. For this reason, the waste water discharged from the use point 14 includes various components at various concentrations.

Among the wastewater discharged from each use point 14, wastewater containing an inorganic ion component having a concentration of 0.01 to 1000 mg / l (hereinafter also referred to as “utilized wastewater”) is directly connected to the electrode deionizer through the first drainage pipe 18. 15 is supplied. As described above, each drainage discharged for each use point 14 is composed of a hydrofluoric acid component, an acid or alkali component, an organic component, a polishing component such as silicon powder, a polishing slurry, silicon, or a metal piece. Water containing chemical or mechanical polishing system components. Among these, the wastewater used is 0.01 to 1000 mg / l, preferably 0.1 to 100 mg / l, more preferably 1 to 10 mg / l. For example, hydrous acid-based components (HF, NH ₄ F, etc.) containing wafer cleaning waste water, acid-based or alkaline components (HCl, HNO ₃ , H ₂ SO ₄ , _{H 3 PO 4, CH 3 COOH} , H 2 O 2, NH 4 OH , etc.) containing wastewater, organic components (IPA, acetone, surfactants, TMAH) containing wastewater, other acids or Al Wastewater containing Li component, drainage and the like made of a single component. Conventionally, inorganic wastewater obtained from a use point is a mixed wastewater obtained from a plurality of use points, and since the concentration was not constant, it could not be supplied directly to an electrodeionization device. For example, since wastewater is collected for each point of use, components and concentrations are specified, and treatment with an electrodeionization device is possible. In this example, the used wastewater is directly supplied to the electrodeionization device 15 through the first drainage pipe 18, but the present invention is not limited to this. For example, in order to remove caustic soda in the used wastewater, Pretreatment means such as polisher-type activated carbon may be provided in front of the ion device 15.

  Examples of the method of selecting the use wastewater from each drainage discharged for each use point 14 include a method of judging from the use history of ultrapure water at the use point 14 and a method of judging from a water quality inspection of waste water. . In addition, wastewater other than used wastewater is sent to the wastewater collection facility 17 through the second drainage pipe 19, and the treated water in the wastewater collection facility 17 is returned to the primary pure water production device 12 or the pretreatment device 11. Even in the wastewater recovery method of the present invention, although the wastewater recovery facility 17 is required, the wastewater to be treated is reduced in volume, the scale of the wastewater recovery facility 17 is small, and the installation space is not large.

  Examples of the electrodeionization apparatus used in the present invention include an electrodeionization apparatus having a conventional demineralization chamber structure described in the prior art column of JP-A-2001-239270, or described in JP-A-2001-239270. A first small desalting chamber and a second small demineralization chamber which are partitioned by an anion exchange membrane and a cathode side by a cation exchange membrane and by an intermediate ion exchange membrane located between the anion exchange membrane and the cation exchange membrane. An electrodeionization apparatus comprising one or more demineralization chambers including a demineralization chamber, and water to be treated is passed through the first small desalination chamber and the second small desalination chamber in series in this order. Can be used.

  In the electrodeionization apparatus 15 used in the present invention, the concentration chamber is divided into two or more chambers by a diaphragm, and a primary concentration chamber to which dilute concentrated water is supplied and concentrated water that is richer than that are supplied. A secondary concentrating chamber, and the primary concentrating chamber is disposed on one or both of the cathode side and the anode side of the deionization chamber, the deionization chamber / primary concentrating chamber assembly, and the secondary concentrating chamber As long as it is alternately stacked and has two concentrated water circulation systems including a primary concentrated water circulation system that passes through the primary concentration chamber and a secondary concentrated water circulation system that passes through the secondary concentration chamber, The concentrated water discharge 21 can be drastically reduced to 0.0001 to 1% of the wastewater used, and the treatment of the concentrated wastewater becomes unnecessary. For example, when the electrodeionization apparatus is installed in the clean room 16, it is only necessary to install only a transportable waste liquid tank 22 having a small capacity, which is extremely convenient.

  In the electrodeionization apparatus 15 in which the concentrating chamber is divided, the concentrating chamber includes both a primary concentrating chamber and a secondary concentrating chamber, a frame body made of synthetic resin, a rubber packing, a gasket-like frame body, etc. Formed by the use of. In the internal space of the concentration chamber, a conductive or non-conductive water-permeable body may be disposed in order to prevent the membranes from sticking to each other and secure a flow path. Examples of the non-conductive water-permeable body include mesh-like materials, non-woven fabrics, woven fabrics, and other porous materials. Among these, the mesh-like material is easy to select a mesh and has water permeability. It is preferable in that it is excellent and hardly raises the differential pressure in the concentrating chamber.

  The diaphragm of the concentrating chamber may have any function as long as different concentrated water flows between the primary concentrating chamber and the secondary concentrating chamber, and the ion exchange is performed without mixing them. Can be mentioned. As the ion exchange membrane, a cation exchange membrane or an anion exchange membrane can be used, and the ion exchange membrane is selected depending on whether the component to be removed from the liquid to be treated is a cation or an anion.

  The supply liquid supplied to the primary concentrated water circulation system that passes through the primary concentration chamber is not particularly limited. Even if the water is branched from the used wastewater supplied to the deionization chamber, The branch line may be water supplied from a separate line. The primary concentrated water is always circulated. Therefore, a primary concentrated water storage tank and a circulation pump are installed to circulate the primary concentrated water. In addition, you may install the blow piping which discharges a part of primary concentrated water out of the system in the primary concentrated water circulation piping so that the density | concentration of primary concentrated water can be controlled appropriately. The thickness of the concentration chamber, the applied current, the LV of the concentrate, etc. are adjusted so that the concentration of the primary concentrated water is 10 to 1000 times thicker than the water to be treated.

  The secondary concentrated water circulation system passing through the secondary concentration chamber is a circulation system independent of the primary concentrated water circulation system, and the supply water supplied to the secondary concentrated water circulation system is not particularly limited, and is a deionization chamber. Even if it is the water which branches and is supplied from the to-be-processed water (utilization waste_water | drain) supplied to water, the water supplied from a line separate from the branch line from utilization waste_water | drain may be sufficient. Secondary concentrated water is always circulated. Therefore, a secondary concentrated water storage tank and a circulation pump are installed to circulate the secondary concentrated water. In addition, in order to appropriately control the concentration of the secondary concentrated water, the secondary concentrated water circulation pipe is provided with a blow pipe for discharging a part of the secondary concentrated water out of the system. The LV, thickness, applied current, etc. of the concentration chamber are adjusted so that the concentration of the secondary concentrated water is 10 to 1000 times thicker than the primary concentrated solution.

  The primary concentration chamber and the secondary concentration chamber may or may not be filled with an ion exchanger, but at least one of the primary concentration chamber and the secondary concentration chamber has an anion exchanger or a cation exchanger. It is preferable to fill a single bed or a mixed bed in which an anion exchanger and a cation exchanger are mixed at a volume ratio of 1: 9 to 9: 1. These ion exchangers are determined according to the component to be concentrated. Examples of the ion exchanger include ion exchange resins, ion exchange fibers, and porous ion exchangers described in JP-A No. 2002-306976. Both are preferable in that the electrical resistance can be reduced and the concentration factor can be increased.

  The thicknesses of the primary concentration chamber and the secondary concentration chamber are both preferably 0.5 to 6 mm, particularly preferably 1.0 to 5.0 mm. If it is less than 0.5 mm, it is difficult to maintain the structure of the concentration chamber, the ion exchange membranes in the primary concentration chamber and the secondary concentration chamber are likely to come into contact, and the performance of the concentration chamber cannot be exhibited. Also, the water differential pressure is likely to increase. On the other hand, if it exceeds 6 mm, the electrical resistance increases and the power consumption increases. The LV of the concentration chamber is usually about 5 to 200 m / h.

  Next, the operation of the electrodeionization apparatus and electrodeionization apparatus used in the present invention will be described with reference to FIG. FIG. 2 is a flow diagram of an electrodeionization apparatus for obtaining decationized water in which the wastewater used is a cationic impurity-containing wastewater. In FIG. 2, symbol D indicates a decation chamber, C1 indicates a primary concentration chamber, C2 indicates a secondary concentration chamber, E indicates an electrode chamber, A indicates an anion exchange membrane, C indicates a cation exchange membrane, and black inversion indicates a cation exchanger. .

  The electrodeionization device 15a has an electrodeionization device main body 31a, an untreated water inflow pipe 32 through which used wastewater flows into the two decationization chambers D, and an outflow of decationized water from which the treated water in the two decationization chambers D flows out. Pipe 33, primary concentrated water circulation pipe 34 that passes through four primary concentration chambers C1, secondary concentrated water circulation pipe 35 that passes through three secondary concentration chambers C2, and secondary concentrated water blow pipe that branches from secondary concentrated water circulation pipe 35 36.

  The electrodeionization apparatus main body 31a is a decationization chamber filled with a cation exchanger in which an anode chamber E and a cathode chamber E are disposed at both ends, an anode side is partitioned by an anion exchange membrane A, and a cathode side is partitioned by a cation exchange membrane C. D, D and concentration chambers C1, C2 are arranged between the decation chamber D and the decation chamber D, and the concentration chambers C1, C2, decation chamber D, in order from the anode chamber side to the cathode chamber side, The concentration chambers C1, C2, the decation chamber D, the concentration chambers C1, C2, and the primary concentration chamber C1 are arranged.

  The concentrating chamber is divided by the cation exchange membrane C into a primary concentrating chamber C1 to which dilute concentrated water is supplied and a secondary concentrating chamber C2 to which concentrated water more concentrated than that is supplied. The primary concentrating chamber C1 is decationized. Arranged on the cathode side of the chamber D, the assembly of the decation chamber D and the primary concentration chamber C1, and the secondary concentration chamber C2 are alternately stacked. The primary concentration chamber C1 is filled with a cation exchanger. Further, by setting the chamber adjacent to the electrode chamber E as the primary concentration chamber C1, the impurity component does not diffuse into the electrode chamber E, and the problem of corrosion of the electrode E due to the impurity component can be avoided.

Next, a method for operating the electrodeionization apparatus 15a will be described. The waste water containing cationic impurities flows into the decation chamber D through the treated water inflow pipe 32, and decation water can be obtained from the decation chamber D by applying a voltage to the pair of electrodes E. . The cationic impurities removed in the decationization chamber D permeate the cation exchange membrane C and flow into the primary concentration chamber C1. Moreover, since the primary concentration chamber C1 has a deionization function, the cationic impurities pass through the cation exchange membrane C and flow into the secondary concentration chamber C2. For this reason, it is possible to obtain concentrated water in which the cationic impurities are concentrated at a high concentration from the secondary concentration chamber C2 to a concentration ratio of 10 ² to 10 ⁶ . That is, the concentrated water discharged from the secondary concentrated water blow pipe 3 to the outside of the system is an amount of 0.0001 to 1% by volume of treated water, and can be dramatically reduced.

  Next, another electrodeionization apparatus used in the present invention and an operation method of the electrodeionization apparatus will be described with reference to FIG. FIG. 3 is a flow diagram of an electrodeionization apparatus for obtaining a deanion liquid, in which the wastewater used is an anionic impurity-containing wastewater. In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and different points will be mainly described. However, in FIG. 3, the code | symbol D shows a deanion chamber and a pattern part shows an anion exchanger, respectively.

  Electrodeionization device 15b, electrodeionization device main body 31b, treated water inflow piping 32 through which used wastewater flows into the two deanion chambers D, and deionization water outflow piping through which the treated water in the two deanion chambers D flows out 33, the primary concentrated water circulation pipe 34 that passes through the four primary concentration chambers C1, the secondary concentrated water circulation pipe 35 that passes through the three secondary concentration chambers C2, and the secondary concentrated water blow pipe 36 that branches from the secondary concentrated water circulation pipe 35. Is provided.

  The electrodeionization device main body 31b is a deionization chamber filled with an anion exchanger in which an anode chamber E and a cathode chamber E are disposed at both ends, an anode side is partitioned by an anion exchange membrane A, and a cathode side is partitioned by a cation exchange membrane C. D, D, and concentration chambers C1, C2 are arranged between deanion chamber D and deanion chamber D, and in order from the cathode chamber side to the anode chamber side, concentration chambers C1, C2, decation chamber D, The concentration chambers C1, C2, the decation chamber D, the concentration chambers C1, C2, and the primary concentration chamber C1 are arranged.

  The concentrating chamber is divided into a primary concentrating chamber C1 to which dilute concentrated water is supplied and a secondary concentrating chamber C2 to which concentrated concentrated water is supplied by the anion exchange membrane A. The primary concentrating chamber C1 is deionized. It is arrange | positioned at the anode side of the chamber D, and the assembly of the deanion chamber D and the primary concentration chamber C1, and the secondary concentration chamber C2 are laminated | stacked alternately. The primary concentration chamber C1 is filled with an anion exchanger.

Next, a method for operating the electrodeionization device 15b will be described. To-be-treated water containing anionic impurities flows into the deanion chamber D through the to-be-treated water inflow pipe 32 and applies a voltage to the pair of electrodes E to obtain deanion water from the deanion chamber D. it can. The anionic impurities removed in the deanion chamber D permeate the anion exchange membrane A and flow into the primary concentration chamber C1. Since the primary concentration chamber C1 has a deionization function, the anionic impurities pass through the anion exchange membrane A and flow into the secondary concentration chamber C2. For this reason, it is possible to obtain concentrated water in which the anionic impurities are concentrated at a high concentration from the secondary concentration chamber C2 to a concentration ratio of 10 ² to 10 ⁶ .

  Next, another electrodeionization apparatus used in the present invention and an operation method of the electrodeionization apparatus will be described with reference to FIG. FIG. 4 is a flow diagram of the electrodeionization apparatus. 4, the same components as those in FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and different points will be mainly described. However, in FIG. 4, the code | symbol D shows a deionization chamber, and a shaded part shows the mixed ion exchanger of a cation exchanger and an anion exchanger, respectively.

  The electrodeionization device 15c includes an electrodeionization device main body 31c, an untreated water inflow pipe 32 through which treated water flows into the two deionization chambers D, and deionized water from which the treated water from the two deionization chambers D flows out. Outflow pipe 33, primary concentrated water circulation pipe 34 that passes through six primary concentration chambers C1, secondary concentrated water circulation pipe 35 that passes through three secondary concentration chambers C2, and secondary concentrated water blow that branches from secondary concentrated water circulation pipe 35 A pipe 36 is provided.

  The electrodeionization device main body 31c is a deionization chamber filled with an anion exchanger in which an anode chamber E and a cathode chamber E are arranged at both ends, an anode side is partitioned by an anion exchange membrane A, and a cathode side is partitioned by a cation exchange membrane C. D, D and concentration chambers C1, C2, C1 are arranged between deionization chamber D and deionization chamber D, and concentration chambers C1, C2, C1, deionization are sequentially performed from the cathode chamber side toward the anode chamber side. An ion chamber D, concentration chambers C1, C2, and C1, a deionization chamber D, and concentration chambers C1, C2, and C1 are arranged.

  The concentration chamber is divided into three by an anion exchange membrane A and a cation exchange membrane C into a primary concentration chamber C1, C1 to which dilute concentrated water is supplied and a secondary concentration chamber C2 to which concentrated water is concentrated. The primary concentration chamber C1 is disposed on both the anode side and the cathode side of the deionization chamber D, and the deionization chamber D, the joined body of the two primary concentration chambers C1 and C1, and the secondary concentration chamber C2 are alternately stacked. It is a thing. The primary concentration chamber C1 is filled with a mixed ion exchanger of a cation exchanger and an anion exchanger. However, the present invention is not limited to this, and the primary concentration chamber C1 disposed on the anode side of the desalting chamber has an anion. The primary concentration chamber C1 disposed on the cathode side of the desalting chamber may be filled with the cation exchanger bed.

Next, the operation method of the electrodeionization device 15c will be described. To-be-treated water containing ionic impurities flows into the deionization chamber D through the to-be-treated water inflow pipe 32 and deionized water can be obtained from the deionization chamber D by applying a voltage to the pair of electrodes E. it can. Of the ionic impurities removed in the deionization chamber D, the anionic impurities pass through the anion exchange membrane A and flow into the primary concentration chamber C1 located on the anode side. Further, since the primary concentration chamber C1 has a deionization function, the anionic impurities pass through the anion exchange membrane A and flow into the secondary concentration chamber C2 located on the anode side. On the other hand, among the ionic impurities removed in the deionization chamber D, the cationic impurities pass through the cation exchange membrane C and flow into the primary concentration chamber C1 located on the cathode side. Similarly, since the primary concentration chamber C1 has a deionization function, the cationic impurities pass through the cation exchange membrane C and flow into the secondary concentration chamber C2 located on the cathode side. For this reason, the concentrated water in which the anionic impurities and the cationic impurities are concentrated at a high concentration up to a concentration ratio of 10 ² to 10 ⁶ can be obtained from the secondary concentration chamber C2. According to the electrodeionization device 15c, since the primary concentration chamber C1 is installed on both sides of the deionization chamber D, the concentrated water of high concentration does not directly diffuse into the deionization chamber D, and the water quality of the treatment liquid is lowered. I will not let you.

  In addition, in the case of the electrodeionization apparatus provided with the desalination chamber which has two small desalination chambers, the desalination chamber D is replaced with the desalination chamber D2 shown in FIG. 5 in FIGS. That is, the cation exchange membrane C on one side, the anion exchange membrane A on the other side, and the intermediate ion exchange membrane 38 located in the middle thereof are partitioned into two small deionization chambers d1 and d2, and one of the small deionization chambers d1 The outflow pipe 32a and the inflow pipe 32b of the other small deionization chamber d2 are connected. The ion exchanger filled in the small deionization chambers d1 and d2 is not particularly limited, and may be any of a cation exchanger, an anion exchanger, and a mixed ion exchanger of a cation exchanger and an anion exchanger. Further, the intermediate ion exchange membrane may be either an anion membrane or a cation membrane, and may be, for example, a duplex membrane that is divided into two in the inflow direction and one is an anion membrane and the other is a cation membrane.

  According to the electrodeionization apparatus provided with the desalination chamber having two small desalination chambers, the same effect as the electrodeionization apparatus 15a can be obtained, and the concentration chamber per deionization chamber filled with the ion exchanger. Can be halved and the electrical resistance can be significantly reduced. Further, since the number of the concentration chambers is reduced, the concentration of the concentrated liquid flowing through the concentration chamber can be made thicker. Moreover, the processing performance of the mixed component of a cation and an anion is improved. In particular, when processing a mixed component containing either an anion or a cation component such as acid or alkali in a large amount, the small desalting chamber d1 is filled with an ion exchanger capable of removing the component to be removed, and the small desalting chamber The treatment performance is improved by using d2 as a mixed floor. And the component which is hard to remove among anions and cations can be removed selectively.

  In the present invention, the treated water of the electrodeionization apparatus 15 is returned to the ultrapure water production apparatus 20 through the return pipe 23. Specifically, you may return to any of the secondary pure water manufacturing apparatus 13, the primary pure water manufacturing apparatus 12, and the pretreatment apparatus 11. Thereby, since the wastewater is reused, the utilization rate of the water in the wastewater recovery device is increased.

  In the present invention, the use point 14 and the electrodeionization device 15 can be installed in the same facility. Here, the same facility refers to a building or a room placed under the same environment, for example, a clean room. Since the electrodeionization device 15 does not require a wide installation space, it can be installed in the same facility as the use point 14. Treating the wastewater discharged from the use point 14 with the electrodeionization device installed in the same room eliminates the need for installing a pipe to the wastewater treatment facility, and can reduce the installation space. It is convenient to increase the cleanliness because it is possible to omit the installation of drainage pipes penetrating the walls. In addition, the volume of wastewater other than used wastewater is reduced, and there is no need to install a large-scale wastewater recovery facility outside the facility.

It is a flowchart of the waste_water | drain collection | recovery apparatus in this Embodiment. It is a flowchart of the electrodeionization apparatus used by this invention. It is a flowchart of the other electrodeionization apparatus used by this invention. It is a flowchart of the other electrodeionization apparatus used by this invention. It is a flowchart of the other demineralization chamber structure of the electrodeionization apparatus used by this invention. It is a flowchart of the conventional waste_water | drain collection | recovery apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wastewater recovery device 11 Pretreatment device 12 Primary pure water production device 13 Secondary pure water production device 14 Use point 15, 15a-15c Electrodeionization device 16 Clean room 17 Wastewater recovery equipment 18 First drainage pipe 19 Second drainage pipe 20 Ultrapure water production equipment 21 Concentrated waste water 22 Waste liquid container 23 Return piping 31a to 31c Electrodeionization equipment body 32 Water to be treated inflow pipe 33 Treated water outflow pipe 34 Primary concentrated water circulation system 35 Secondary concentrated water circulation system 36 Secondary concentrated water blow pipe C1 Primary concentration chamber C2 Secondary concentration chamber D Desalination chamber C Cation exchange membrane A Anion exchange membrane

Claims (9)

  Pure water or ultrapure water obtained with pure water or ultrapure water production equipment is supplied to each use point, and among the waste water discharged from each use point, an inorganic ion component having a concentration of 0.01 to 1000 mg / l A wastewater recovery method comprising: supplying wastewater containing water to an electrodeionization device to perform deionization treatment, and returning treated water of the electrodeionization device to the ultrapure water production device.   The waste water recovery method according to claim 1, wherein the use point and the electrodeionization apparatus are installed in the same facility.   The wastewater recovery method according to claim 1 or 2, wherein the facility is a clean room. The electrodeionization apparatus has a deionization chamber, a concentration chamber, and an electrode chamber, and obtains deionized water from the deionization chamber by applying a voltage to a pair of electrodes, the concentration chamber having a diaphragm Is divided into two or more chambers, and is composed of a primary concentrating chamber to which dilute concentrated water is supplied and a secondary concentrating chamber to which concentrated concentrated water is supplied. The primary concentrating chamber is on the cathode side of the deionization chamber. Or arranged on one or both of the anode side,
The assembly of the deionization chamber and the primary concentration chamber, and the secondary concentration chamber are alternately stacked,
The waste water recovery according to any one of claims 1 to 3, comprising a primary concentrated water circulation system passing through the primary concentration chamber and a secondary concentrated water circulation system passing through the secondary concentration chamber. Method.   The concentrated water discharged from the system by circulating the concentrated water of the electrodeionization apparatus is 0.0001 to 1% by volume of the treated water amount of the electrodeionization apparatus. The waste water recovery method of any one of -4.   Of the waste water discharged from each use point, having an ultra pure water production device for producing pure water or ultra pure water, each use point using the pure water or ultra pure water, and an electrodeionization device , A first drainage pipe for allowing wastewater containing an inorganic ion component having a concentration of 0.01 to 1000 mg / l to flow into the deionization chamber of the electrodeionization device, and treating the treated water of the electrodeionization device with the pure water or ultrapure water. A wastewater recovery apparatus comprising a return pipe for returning to a pure water production apparatus.   The wastewater recovery apparatus according to claim 6, wherein the use point and the electrodeionization apparatus are installed in the same facility.   The wastewater recovery apparatus according to claim 6 or 7, wherein the facility is a clean room. The electrodeionization apparatus has a deionization chamber, a concentration chamber, and an electrode chamber, and obtains deionized water from the deionization chamber by applying a voltage to a pair of electrodes, the concentration chamber having a diaphragm Is divided into two or more chambers, and is composed of a primary concentrating chamber to which dilute concentrated water is supplied and a secondary concentrating chamber to which concentrated concentrated water is supplied. The primary concentrating chamber is on the cathode side of the deionization chamber. Or arranged on one or both of the anode side,
The assembly of the deionization chamber and the primary concentration chamber, and the secondary concentration chamber are alternately stacked,
The waste water recovery according to any one of claims 6 to 8, comprising a primary concentrated water circulation system passing through the primary concentration chamber and a secondary concentrated water circulation system passing through the secondary concentration chamber. apparatus.

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