JP2018114490A - Method and apparatus for purifying phosphorus-containing high hardness water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for purifying phosphorus-containing high-hardness water capable of stable operation of a water treatment facility and reduction of power consumption by reducing clogging of a filter membrane. A purification method according to one aspect of the present invention is a method for purifying phosphorus-containing high-hardness water containing a hardness component and phosphoric acid, and apatite production that produces apatite by adjusting the pH of the phosphorus-containing high-hardness water. A membrane treatment in which the treated water after the apatite formation step is separated into a solid-liquid separation step, and the treated water from which the solid content is separated in the solid-liquid separation step is separated by an ultrafiltration membrane or a precision filtration membrane. It has a process. [Selection diagram] Fig. 1

Description

  The present invention relates to a purification method and a purification device for phosphorus-containing high-hardness water.

  In recent years, water treatment apparatuses have been used to treat and reuse raw water such as sewage and factory effluent. As this water treatment device, for example, an ultrafiltration membrane or a microfiltration membrane that removes turbidity from raw water, and a reverse osmosis membrane that separates the membrane permeate that has permeated this filter membrane into a reverse osmosis membrane permeate and a concentrated liquid. It has been known (see Table 2011-016410).

No. 2011-016410

  However, when the raw water that is the target of water treatment is phosphorus-containing high-hardness water containing a hardness component and phosphoric acid, when the conventional water treatment apparatus is used, the hardness component and phosphoric acid in the raw water are filtered membranes. It is concentrated on the surface to become a precipitate, and the film is frequently clogged. For this reason, chemical cleaning of the filtration membrane is frequently required, and it is difficult to stably operate the water treatment facility. Further, the permeation flux and the recovery rate are likely to decrease due to the precipitates, and it is difficult to stably supply reused water. Furthermore, the operation in a state where the differential pressure of the filtration membrane is high is likely to continue, and the power consumption of the water treatment device per unit treatment amount is likely to increase. For this reason, a purification method and a purification device for phosphorus-containing high hardness water are desired.

  The present invention has been made based on the above situation, and a method for purifying phosphorus-containing high-hardness water capable of stable operation of water treatment equipment and reduction of power consumption by reducing clogging of a filtration membrane. And it aims at provision of a purification device.

  A purification method according to one aspect of the present invention made to solve the above problems is a purification method of phosphorus-containing high-hardness water containing a hardness component and phosphoric acid, wherein the apatite is adjusted by adjusting the pH of the phosphorus-containing high-hardness water. An apatite production step for producing a solid, a solid-liquid separation step for solid-liquid separation of the treated water after the apatite production step, and treated water obtained by separating the solid content in the solid-liquid separation step with an ultrafiltration membrane or a microfiltration membrane. A membrane treatment step for membrane separation.

  A purification apparatus according to another aspect of the present invention is a purification apparatus for phosphorus-containing high hardness water containing a hardness component and phosphoric acid, and an apatite generation section that generates apatite by adjusting the pH of phosphorus-containing high hardness water; A solid-liquid separation unit for solid-liquid separation of the treated water in which the apatite is produced in the apatite production unit, and a membrane treatment for separating the treated water separated in the solid-liquid separation unit with an ultrafiltration membrane or a microfiltration membrane A part.

  By using the method and apparatus for purifying phosphorus-containing high-hardness water according to the present invention, stable operation of water treatment facilities and reduction of power consumption by reducing clogging of the filtration membrane can be achieved.

FIG. 1 is a schematic view showing a purification device according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a configuration example of the stirring device of the purification device of FIG. 1. FIG. 3 is a schematic diagram illustrating a configuration example of a stirring device different from that in FIG. 2. FIG. 4 is a schematic view showing a purification device different from FIG. FIG. 5 is a graph showing the relationship between the pH adjustment value in the apatite production step and the differential pressure of the filtration membrane. FIG. 6 is a graph showing a comparison of the differential pressure of the filtration membrane with and without apatite formation.

[Description of Embodiment of the Present Invention]
First, embodiments of the present invention will be listed and described.

  A purification method according to one aspect of the present invention is a purification method of phosphorus-containing high hardness water containing a hardness component and phosphoric acid, wherein the apatite generation step generates apatite by adjusting the pH of the phosphorus-containing high hardness water, and A solid-liquid separation step for solid-liquid separation of the treated water after the apatite generation step, and a membrane treatment step for membrane separation of the treated water separated in the solid-liquid separation step with an ultrafiltration membrane or a microfiltration membrane .

  In the cleaning method for phosphorus-containing high-hardness water, apatite is generated by calcium and phosphoric acid contained in the phosphorus-containing high-hardness water by adjusting the pH of the phosphorus-containing high-hardness water in the apatite generation step. In the method for purifying phosphorus-containing high-hardness water, the apatite is separated as a solid in the solid-liquid separation step, so that the hardness component and phosphoric acid contained in the treated water separated in the membrane treatment step can be reduced. For this reason, the washing | cleaning method of the said phosphorus containing high hardness water can reduce the clogging of the film | membrane by a hardness component and phosphoric acid. Therefore, by using the method for purifying phosphorus-containing high-hardness water, it is possible to stably operate the water treatment facility and reduce power consumption by reducing clogging of the filtration membrane.

  It is preferable to further include a sedimentation separation step of sedimenting and separating organic matter contained in the phosphorus-containing high-hardness water with a flocculant after the apatite generation step and before the solid-liquid separation step. In the sedimentation separation step, the organic substance in the phosphorus-containing high-hardness water aggregates with apatite as the core by adding a flocculant. By separating and aggregating the agglomerated organic matter, the organic matter adhering to the membrane surface in the membrane treatment step can be reduced, so that clogging of the filtration membrane can be further reduced.

  The apatite is preferably hydroxyapatite. Hydroxyapatite can be efficiently removed by solid-liquid separation. Hydroxyapatite may remain in the treated water after the solid-liquid separation process, but it is difficult to adhere to the ultrafiltration membrane and the microfiltration membrane and easily peels off even if it adheres, so it can be easily removed by washing, etc. can do. For this reason, the effect of reducing power consumption can be enhanced.

  The pH adjustment value in the apatite production step is preferably 8.25 or more and 9.5 or less. By making the pH adjustment value in the apatite production step within the above range, the production efficiency of apatite from calcium and phosphoric acid can be increased, so the removal efficiency of calcium and phosphoric acid from phosphorus-containing high hardness water can be enhanced. Therefore, clogging of the filtration membrane can be further reduced.

  An acid injection step of injecting acid into the membrane permeated water obtained in the membrane treatment step and a reverse osmosis membrane treatment step of separating the membrane permeated water after the acid injection step with a reverse osmosis membrane may be further provided. By injecting acid into the membrane permeate obtained in the membrane treatment step, the hardness component contributing to the formation of apatite remaining in the membrane permeate can be dissolved. The membrane permeated water after this acid injection step is separated in the reverse osmosis membrane treatment step, so that the reverse osmosis membrane is prevented from being clogged with apatite, while the concentrated water containing impurities such as salt and the impurities are substantially removed. The reverse osmosis membrane permeated water not contained can be separated.

  The pH adjustment value of the membrane permeated water in the acid injection step is preferably 5 or more and 6.5 or less. By adjusting the pH adjustment value of the permeated water in the acid injection step within the above range, the dissolution efficiency of the apatite can be increased while suppressing the deterioration of the reverse osmosis membrane due to the acid and the reduction of the rejection rate. The effect of preventing clogging of the osmotic membrane can be enhanced.

  It is preferable to further include a reverse washing step of reverse washing the ultrafiltration membrane or the microfiltration membrane with the reverse osmosis membrane permeated water obtained in the reverse osmosis membrane treatment step. Since the reverse osmosis membrane permeated water obtained in the above reverse osmosis membrane treatment step is acidic, the ultrafiltration membrane or the microfiltration membrane is back-washed with this reverse osmosis membrane permeated water, so that the ultrafiltration membrane or Apatite adhering to the microfiltration membrane can be dissolved and efficiently removed. For this reason, the power consumption required in the back washing process can be reduced.

  A purification apparatus according to another aspect of the present invention is a purification apparatus for phosphorus-containing high hardness water containing a hardness component and phosphoric acid, and an apatite generation section that generates apatite by adjusting the pH of phosphorus-containing high hardness water; A solid-liquid separation unit for solid-liquid separation of the treated water in which the apatite is produced in the apatite production unit, and a membrane treatment for separating the treated water separated in the solid-liquid separation unit with an ultrafiltration membrane or a microfiltration membrane A part.

  The said phosphorus containing high hardness water washing | cleaning apparatus produces | generates apatite with the calcium and phosphoric acid which are contained in phosphorus containing high hardness water by adjusting the pH of phosphorus containing high hardness water in an apatite production | generation part. The said phosphorus containing high hardness water purification apparatus can reduce the hardness component and phosphoric acid which are contained in the treated water which carries out membrane separation in a membrane treatment part by isolate | separating this apatite as a solid in a solid-liquid separation part. For this reason, the said phosphorus containing high hardness water washing | cleaning apparatus can reduce the clogging of the film | membrane by a hardness component and phosphoric acid. Therefore, by using the phosphorus-containing high-hardness water purification device, it is possible to stably operate the water treatment facility and reduce power consumption by reducing clogging of the filtration membrane.

  It is preferable to further include a sedimentation separation unit that precipitates and separates organic matter contained in the phosphorus-containing high-hardness water with a flocculant between the apatite generation unit and the solid-liquid separation unit. By adding a flocculant in the sedimentation separation unit, organic matter in the phosphorus-containing high-hardness water aggregates with apatite as a nucleus. By separating and aggregating the agglomerated organic matter, the organic matter adhering to the membrane surface in the membrane treatment unit can be reduced, so that clogging of the filtration membrane can be further reduced.

  An acid injection unit for injecting acid into the membrane permeated water obtained by the membrane treatment unit, and a reverse osmosis membrane treatment unit for separating the membrane permeated water injected with the acid by the acid injection unit with a reverse osmosis membrane Good. By injecting acid into the membrane permeated water obtained in the membrane treatment unit at the acid injecting unit, the hardness component contributing to the generation of apatite remaining in the membrane permeated water can be dissolved. Since the permeated water injected with acid in this acid injection part is separated in the reverse osmosis membrane treatment part, the reverse osmosis membrane is prevented from being clogged with apatite, and concentrated water containing impurities such as salt, Reverse osmosis membrane permeated water substantially free of impurities can be separated.

  It is good to have further the neutralization tank which neutralizes the solid content concentrate isolate | separated by the said solid-liquid separation part, and to have the flow path which supplies the concentrated water obtained by the said reverse osmosis membrane process part to the said neutralization tank. The concentrated water obtained in the reverse osmosis membrane treatment part is acidic. By supplying this concentrated water to the neutralization tank via the flow path and using it for neutralization, water treatment can be performed efficiently without the need for a new acid or the like, so that power consumption can be further reduced.

  It is preferable to further include a reverse cleaning mechanism for back cleaning the ultrafiltration membrane or the microfiltration membrane with the reverse osmosis membrane permeated water obtained in the reverse osmosis membrane treatment unit. Since the reverse osmosis membrane permeated water obtained in the reverse osmosis membrane treatment unit is acidic, the reverse filtration of the ultrafiltration membrane or the microfiltration membrane with the reverse osmosis membrane permeate allows the ultrafiltration membrane or the precision filtration membrane to be washed back. Apatite adhering to the filtration membrane can be dissolved and efficiently removed. For this reason, the power consumption required by the reverse cleaning mechanism can be reduced.

  The apatite generation unit may include a pump for supplying a pH adjusting agent and a stirring device for stirring the pH adjusting agent, and the stirring device may include an in-line mixer or an aeration tank. When the stirring device includes an in-line mixer, the pH of the phosphorus-containing high-hardness water can be easily made uniform. Moreover, since the stirring device includes an aeration tank, gentle stirring can be performed, so that the particle size of the apatite to be generated increases. For this reason, the separation efficiency of the apatite in the solid-liquid separation part is improved. Further, since aeration can be performed with relatively low power, power consumption can be further reduced.

  The pH adjuster is preferably sodium hydroxide. By using sodium hydroxide, which has a high degree of ionization and can be obtained at a low cost, as the pH adjuster, it is possible to increase the production efficiency of apatite, so that the effect of inhibiting clogging of the reverse osmosis membrane can be enhanced.

  In this application, “microfiltration membrane” means a filtration membrane having an average diameter of membrane pores of more than 0.1 μm and not more than 10 μm, and “ultrafiltration membrane” means an average diameter of membrane pores of 0.002 μm. It means a filtration membrane that is ultra 0.1 μm or less, and “reverse osmosis membrane” means a semipermeable membrane having an average diameter of membrane pores of 2 nm or less. In addition, the average diameter of a membrane hole means the average diameter of the void | hole in the surface of a filtration membrane or a semipermeable membrane, and a pore diameter distribution measuring apparatus (For example, the porous material automatic pore diameter distribution measuring system by Porous Materials) Can be measured.

[Details of the embodiment of the present invention]
Hereinafter, a cleaning method and a cleaning apparatus for phosphorus-containing high-hardness water according to an embodiment of the present invention will be described with reference to the drawings as appropriate.

[First embodiment]
The said purification method is a purification method of the phosphorus containing high hardness water containing a hardness component and phosphoric acid. The purification method mainly includes an apatite generation step, a solid-liquid separation step, a membrane treatment step, an acid injection step, a reverse osmosis membrane treatment step, a neutralization treatment step, and a reverse washing step.

  For the purification method, for example, a purification device shown in FIG. 1 is used. The purification device of FIG. 1 is a purification device of phosphorus-containing high hardness water X containing a hardness component and phosphoric acid. The purification apparatus includes an apatite generation unit 1, a solid-liquid separation unit 2, a membrane treatment unit 3, an acid injection unit 4, a reverse osmosis membrane treatment unit 5, a reverse cleaning mechanism 6, and a neutralization tank 7. Prepare mainly. Furthermore, the purification device has a flow path 8 for supplying concentrated water obtained by the reverse osmosis membrane treatment unit 5 to the neutralization tank 7.

  In the apatite generation step, apatite is generated by calcium and phosphoric acid contained in the phosphorus-containing high hardness water X by adjusting the pH of the phosphorus-containing high hardness water X in the apatite generation section 1. In the solid-liquid separation step, the treated water in which apatite is generated in the apatite generation unit 1 in the solid-liquid separation unit 2 is subjected to solid-liquid separation. In the membrane treatment step, the treated water from which the solid content has been separated by the solid-liquid separation unit 2 in the membrane treatment unit 3 is subjected to membrane separation using an ultrafiltration membrane or a microfiltration membrane.

  The phosphorus-containing high-hardness water cleaning method and the purification device are the above-described calcium and phosphoric acid contained in the phosphorus-containing high-hardness water X by adjusting the pH of the phosphorus-containing high-hardness water X in the apatite generation unit 1 as described above. Produces apatite. The purification method and the purification device for the phosphorus-containing high hardness water X are obtained by separating the apatite as a solid in the solid-liquid separation unit 2 so that the hardness component and phosphoric acid contained in the treated water separated by the membrane treatment unit 3 can be obtained. Can be reduced. For this reason, the washing | cleaning method and washing | cleaning apparatus of the said phosphorus containing high hardness water can reduce the clogging of the film | membrane by a hardness component and phosphoric acid. Therefore, by using the method and apparatus for purifying phosphorus-containing high hardness water, it is possible to stably operate the water treatment facility and reduce power consumption by reducing clogging of the filtration membrane 3a.

[Purification device]
The said purification apparatus discharge | releases the reuse water Z out of the system which contains the phosphorus containing high hardness water storage part 9 which stores the phosphorus containing high hardness water X temporarily, the waste water storage tank 10 which stores the discharge water Y temporarily. A pump 11 is further provided.

<Phosphorus-containing high hardness water reservoir>
The phosphorus-containing high hardness water storage unit 9 is introduced with the phosphorus-containing high hardness water X and the phosphorus-containing high hardness water storage tank 9a for temporarily storing the phosphorus-containing high hardness water X, and the phosphorus-containing high hardness water. A pump 9b that pumps the phosphorus-containing high-hardness water X stored in the storage tank 9a to the apatite generation unit 1 side. The phosphorus-containing high hardness water storage section 9 supplies the phosphorus-containing high hardness water X to the apatite generation section 1 by pumping the phosphorus-containing high hardness water X stored in the phosphorus-containing high hardness water storage tank 9a by the pump 9b. It is configured to be possible.

<Apatite generator>
The apatite generator 1 includes a pump 1a for supplying the pH adjuster A to the phosphorus-containing high hardness water X, a stirring device 1b for stirring the pH adjuster A in the phosphorus-containing high hardness water X, and a pH measuring device 1c. Have.

  This apatite production | generation part 1 produces | generates apatite by supplying the pH adjuster A and adjusting the pH of the phosphorus containing high hardness water X. FIG. Apatite is a compound containing calcium and phosphoric acid, and can be separated as a solid content in the solid-liquid separation unit 2 described later. Therefore, the purification apparatus can simultaneously reduce calcium and phosphoric acid in the phosphorus-containing high hardness water X.

The apatite is preferably hydroxyapatite. Hydroxyapatite can be efficiently removed by solid-liquid separation. Hydroxyapatite may remain in the treated water after solid-liquid separation, but it is difficult to adhere to the filtration membrane 3a and easily peels off even if attached, so that it can be easily removed by washing or the like. For this reason, the reduction effect of the power consumption of the said purification apparatus can be heightened. Hydroxyapatite contains a hydroxyl group as a monovalent anion in apatite. By adjusting pH in the presence of OH ⁻ ions, ₁₀ Ca ²⁺ + 6PO ₄ ^{3 −} + 2OH ⁻ → Ca ₁₀ (PO _{4 6} (OH) ₂
It can produce | generate by reaction of these.

  As said pH adjuster A, an alkali is preferable from a viewpoint of the production | generation efficiency of apatite. As the alkali, those having a high degree of ionization are preferable from the viewpoint of producing hydroxyapatite. For example, sodium hydroxide, potassium hydroxide, or the like can be used. Of these, sodium hydroxide is preferably used. For example, granular or flake hydrate may be used as sodium hydroxide, but an aqueous solution having a concentration of about 50% by mass may be used. Such an aqueous sodium hydroxide solution is widely used for industrial use because it is relatively inexpensive and easy to handle.

  The pump 1a supplies the pH adjusting agent A to the stirring device 1b. The supply amount of the pH adjusting agent A is controlled by the pump 1a, and the pH of the treated water in which the pH adjusting agent A and the phosphorus-containing high hardness water X are mixed can be adjusted.

  The stirring device 1b stirs the pH adjuster A supplied to the phosphorus-containing high hardness water X. As said stirring apparatus 1b, what is equipped with the mixing tank 12 as shown in FIG. In the stirring device 1 b shown in FIG. 2, the pH adjuster A is mixed with the phosphorus-containing high hardness water X, stirred by the in-line mixer 13, and then stored in the mixing tank 12. The in-line mixer is easy to make the pH uniform, and the controllability of pH adjustment of the phosphorus-containing high hardness water X is good.

  Moreover, the aeration tank 15 which has the bubble supply mechanism 14 as shown in FIG. 3 can also be used as the said stirring apparatus 1b. In the stirring device 1 b shown in FIG. 3, the pH adjuster A and the phosphorus-containing high hardness water X are supplied to the aeration tank 15. The bubble supply mechanism 14 supplies bubbles D into the aeration tank 15 by air C supplied from the outside, and agitates the pH adjuster A in the phosphorus-containing high hardness water X. As described above, since the agitating device 1b includes the aeration tank 15, since the agitating can be performed gently, the particle diameter of the apatite to be generated increases. For this reason, the separation efficiency of the apatite in the solid-liquid separation unit 2 is improved. Further, since aeration can be performed with relatively low power, the power consumption of the purification device can be further reduced.

When the aeration tank 15 is used as the stirring device 1b, the lower limit of the amount of aeration (the amount of air C supplied) per 1 m ^{3 of} phosphorus-containing high hardness water to be stirred is preferably 10 L / min, and more preferably 20 L / min. On the other hand, the upper limit of the aeration amount is preferably 100 L / min, and more preferably 50 L / min. When the aeration amount is less than the lower limit, the pH adjusting agent A is not sufficiently stirred and apatite may not be generated sufficiently. On the contrary, if the aeration amount exceeds the upper limit, the effect of reducing the power consumption of the purification device may be insufficient, or the particle size of the apatite to be generated becomes small, so that the separation in the solid-liquid separation unit 2 is difficult. There is a risk of becoming.

  The lower limit of the average diameter of the bubbles D supplied from the bubble supply mechanism 14 is preferably 0.5 mm, and more preferably 1 mm. On the other hand, the upper limit of the average diameter of the bubbles D is preferably 5 mm, and more preferably 4.5 mm. When the average diameter of the bubbles D is less than the lower limit, the pH adjuster A may be insufficiently stirred. Conversely, if the average diameter of the bubbles D exceeds the upper limit, the pH of the phosphorus-containing high hardness water X may be insufficiently uniform. The average bubble diameter can be calculated, for example, by shooting rising bubbles with a CCD camera or the like from a direction perpendicular to the vertical axis, and analyzing the captured image. Specifically, the diameter of a circle having an equivalent area is calculated from the shape of the bubble photographed for each bubble diameter, and the average value is obtained.

  As a minimum of residence time of phosphorus content high hardness water X in the aeration tank 15, 5 minutes are preferred and 7 minutes are more preferred. On the other hand, the upper limit of the residence time is preferably 10 minutes, and more preferably 8 minutes. If the residence time is less than the lower limit, apatite formation may be insufficient. On the contrary, if the residence time exceeds the upper limit, the capacity of the aeration tank 15 necessary for storing the phosphorus-containing high hardness water X increases, so that the equipment cost may increase.

  The pH measuring device 1c measures the pH of the phosphorus-containing high hardness water X in the stirring device 1b. In the apatite generator 1, the pH can be adjusted by controlling, for example, the supply amount of the pH adjusting agent A by the pump 1a based on the pH measured by the pH measuring device 1c.

<Solid-liquid separation unit>
The solid-liquid separation unit 2 includes a solid-liquid separation device 2a that solid-liquid separates the treated water that has generated apatite in the apatite generation unit 1, and a solid-liquid separated treated water storage that temporarily stores the treated water from which the solid content has been separated. And a tank 2b. The solid-liquid separation unit 2 has a solid-concentrated liquid discharge pipe 2c that discharges the solid-concentrated liquid discharged from the solid-liquid separator 2a to a neutralization tank 7 described later.

  As the solid-liquid separation device 2a, a known solid-liquid separation device such as a sand filtration device or a liquid cyclone can be used. By this solid-liquid separator 2a, apatite is mainly separated as a solid content into a solid content concentrate. Therefore, the said purification apparatus can reduce the hardness component and phosphoric acid which are contained in the treated water membrane-separated by the membrane process part 3. FIG.

<Membrane treatment part>
The membrane treatment unit 3 includes a filtration membrane 3a for membrane separation of treated water sent from the solid-liquid separation unit 2, a membrane permeated water storage tank 3b for temporarily storing membrane permeated water that has permeated the filtration membrane 3a, and a filtration membrane 3a has a pump 3c for pumping the treated water. The membrane processing unit 3 includes a container (not shown) that houses the filtration membrane 3a.

  The membrane treatment unit 3 pumps the treated water to the filtration membrane 3a by the pump 3c, stores the membrane permeated water that has permeated through the filtration membrane 3a in the membrane permeated water storage tank 3b, and contains turbidity contained in the treated water. Suspended substances are captured on the surface of the filtration membrane 3a. In addition, as an operating pressure in case the filtration membrane 3a is an ultrafiltration membrane, it can be 300 kPa or less, for example. Moreover, as an operating pressure in case the filtration membrane 3a is a microfiltration membrane, it can be 200 kPa or less, for example.

  The filtration membrane 3a may be configured as a spiral type or a tubular type, and may be configured as a hollow fiber membrane or a flat membrane. The filtration method using the filtration membrane 3a is not particularly limited, and a known filtration method such as an internal pressure type, an external pressure type, or a cross flow type can be employed.

  As main components of the filtration membrane 3a, for example, polyethylene, polypropylene, polyvinylidene fluoride, ethylene-vinyl alcohol copolymer, polyamide, polyimide, polyetherimide, polystyrene, polysulfone, polyvinyl alcohol, polyphenylene ether, polyphenylene sulfide, cellulose acetate, Examples include polyacrylonitrile and polytetrafluoroethylene (PTFE). Among these, PTFE which is excellent in alkali resistance and acid resistance and is porous is preferable, and uniaxially or biaxially stretched PTFE is more preferable. In addition, other polymers, additives, such as a lubricant, etc. may be suitably mix | blended with the forming material of the filtration membrane 3a. The “main component” refers to a component having the highest content, for example, a component contained in an amount of 50% by mass or more.

<Acid injection part>
The acid injection unit 4 injects acid B into the membrane permeated water obtained by the membrane treatment unit 3. The acid injection part 4 has an acid injection tube 4a. The acid injection pipe 4a is connected in the middle of a pipe for supplying the treated water stored in the membrane permeated water storage tank 3b of the membrane treatment unit 3 to the reverse osmosis membrane treatment unit 5 described later. The acid injection unit 4 can inject the acid B into the membrane permeated water obtained by the membrane treatment unit 3 through the acid injection tube 4a.

  In the purification apparatus, by injecting acid B into the membrane permeated water obtained by the membrane treatment unit 3 at the acid injecting unit 4, the hardness component contributing to the generation of apatite remaining in the membrane permeated water can be dissolved. Since the membrane permeated water into which the acid B is injected by the acid injection unit 4 is separated by the reverse osmosis membrane treatment unit 5 described later, impurities such as salt are prevented while clogging the reverse osmosis membrane 5a by apatite. Concentrated water containing and reverse osmosis membrane permeated water substantially free of impurities can be separated.

  Although it does not specifically limit as said acid B, For example, hydrochloric acid, a sulfuric acid, etc. can be used. Of these, hydrochloric acid is preferred as the calcium salt, in which calcium does not easily precipitate.

<Reverse osmosis membrane processing section>
The reverse osmosis membrane treatment unit 5 separates the membrane permeated water injected with the acid B by the acid injection unit 4 with a reverse osmosis membrane. The reverse osmosis membrane treatment unit 5 temporarily separates the reverse osmosis membrane 5a, which separates the membrane permeated water injected with the acid B in the acid injection unit 4 into reverse osmosis membrane permeated water and concentrated water. A reverse osmosis membrane permeated water storage tank 5b, a concentrated water storage tank 5c for temporarily storing the concentrated water, and a pump 5d for pumping the membrane permeated water to the reverse osmosis membrane 5a. Moreover, the reverse osmosis membrane processing unit 5 includes a container (not shown) that accommodates the reverse osmosis membrane 5a.

  The reverse osmosis membrane treatment unit 5 stores the reverse osmosis membrane permeated water that has permeated through the reverse osmosis membrane 5a among the above-mentioned membrane permeated water in the reverse osmosis membrane permeated water storage tank 5b and the concentration that has not permeated the reverse osmosis membrane 5a. Water is stored in the concentrated water storage tank 5c. In the purification apparatus, since turbidity and suspended solids are captured by the membrane processing unit 3, the concentrated water does not substantially contain turbidity and suspended substances. The operating pressure of the reverse osmosis membrane 5a can be set to 0.1 MPa or more and 8 MPa or less, for example.

  Examples of the main component of the reverse osmosis membrane 5a include synthetic resins such as polyamide and cellulose acetate. The reverse osmosis membrane 5a can be formed of a spiral type or a hollow fiber membrane.

  In addition, the reverse osmosis membrane permeated water storage tank 5b stores the reverse osmosis membrane permeated water storage tank 5b to be discharged out of the system as reused water Z by the pump 11 provided in the reverse osmosis membrane permeated water storage tank 5b.

<Reverse cleaning mechanism>
The reverse cleaning mechanism 6 back-washes the filtration membrane 3a with reverse osmosis membrane permeated water obtained by the reverse osmosis membrane treatment unit 5. The reverse washing mechanism 6 is connected to a container in which the filtration membrane 3a is accommodated, and the washing water supply pipe 6a that supplies the reverse osmosis membrane permeated water in the reverse osmosis membrane permeated water storage tank 5b as the washing water and the filtration membrane 3a are accommodated. And a washing water discharge pipe 6b for discharging the washing water after washing the filtration membrane 3a to the neutralization tank 7. The reverse cleaning mechanism 6 includes a pump 6c disposed in the reverse osmosis membrane permeated water storage tank 5b. The washing water supply pipe 6a is connected to the downstream side of the filtration membrane 3a so that the washing water passes through the filtration membrane 3a in the direction opposite to the direction in which the treatment water passes through the filtration membrane 3a in the membrane treatment unit 3. The

  The reverse cleaning mechanism 6 performs reverse cleaning by pumping the reverse osmosis membrane permeated water stored in the reverse osmosis membrane permeated water storage tank 5b to the filtration membrane 3a side by a pump 6c. Note that the reverse cleaning by the reverse cleaning mechanism 6 is performed in a state where the operation of the filtration membrane 3a is stopped.

  Since the reverse osmosis membrane permeated water obtained in the reverse osmosis membrane treatment unit 5 is acidic, the apatite adhering to the filtration membrane 3a is dissolved by reverse washing the filtration membrane 3a using the reverse osmosis membrane permeated water. Can be removed efficiently. For this reason, the power consumption required by the reverse cleaning mechanism 6 can be reduced.

<Neutralization tank>
The neutralization tank 7 neutralizes the solid content concentrate separated by the solid-liquid separation unit 2. The purification device can supply concentrated water obtained in the reverse osmosis membrane treatment unit 5 to the neutralization tank 7 through the flow path 8. Since the water treatment can be efficiently performed by using this concentrated water for neutralization in the neutralization tank 7, the purification device can further reduce power consumption.

  The neutralization tank 7 is provided with a pump 7a. The said purification apparatus discharge | releases the solid content concentrate after neutralization, and the wash water after washing | cleaning to the waste water storage tank 10 mentioned later using this pump 7a.

<Drainage storage tank>
The drainage storage tank 10 stores the solid concentrate after neutralization sent from the neutralization tank 7 and the cleaning water after cleaning (hereinafter, collectively referred to as “drainage”) in the drainage storage tank 10. Further, the drainage storage tank 10 has a pump 10a that discharges drainage to the outside of the system. The said purification apparatus discharges the waste_water | drain stored in the waste_water | drain storage tank 10 by this pump 10a as the discharge water Y out of the system. In addition, in order to reduce the density | concentration of the waste_water | drain sent from the neutralization tank 7, you may supply the waste water storage tank 10 with some phosphorus containing high hardness water X suitably.

[Purification method]
Next, each step of the purification method using the purification device will be described.

<Apatite production process>
In the apatite production step, apatite is produced by adjusting the pH of the phosphorus-containing high hardness water X in the apatite production unit 1. Specifically, the phosphorus-containing high hardness water X stored in the phosphorus-containing high hardness water storage tank 9a is pumped by the pump 9b to the stirring device 1b of the apatite generation unit 1, and the pump 1a of the apatite generation unit 1 is operated. Then, the pH adjusting agent A is supplied to the stirring device 1b. At this time, the supply amount of the pH adjusting agent A is adjusted by controlling the pump 1a of the apatite generating unit 1 so that the pH value measured by the pH measuring device 1c becomes a desired value.

  The lower limit of the pH adjustment value in the apatite production step is preferably 8.25, more preferably 8.3, and even more preferably 8.4. On the other hand, the upper limit of the pH adjustment value is preferably 9.5, more preferably 9, and even more preferably 8.7. If the pH adjustment value is less than the lower limit, the amount of apatite produced is reduced, so that the effect of reducing hardness components and phosphoric acid is insufficient, and the effect of reducing clogging of the filtration membrane 3a may be insufficient. On the other hand, if the pH adjustment value exceeds the upper limit, the proportion of hydroxide generated is higher than that of apatite, and the clogging reduction effect of the filtration membrane 3a may be insufficient.

<Solid-liquid separation process>
In the solid-liquid separation step, the solid-liquid separation unit 2 performs solid-liquid separation of the treated water after the apatite generation step. Specifically, the treated water from which the solid content has been separated using the solid-liquid separator 2a is stored in the solid-liquid separated treated water storage tank 2b. On the other hand, the solid concentrate discharged from the solid-liquid separator 2a is discharged to the neutralization tank 7 via the solid concentrate discharge pipe 2c.

<Membrane treatment process>
In the membrane treatment step, the treated water from which the solid content has been separated in the solid-liquid separation step in the membrane treatment unit 3 is membrane-separated by the filtration membrane 3a. Specifically, the treated water stored in the solid-liquid separated treated water storage tank 2b is pumped to the filtration membrane 3a by the pump 3c, and membrane separation is performed by the filtration membrane 3a. The membrane permeated water that has passed through the filtration membrane 3a is stored in the membrane permeated water storage tank 3b. By this membrane separation, turbidity and suspended solids contained in the treated water can be separated.

<Acid injection process>
In the acid injection step, acid B is injected into the membrane permeated water obtained in the membrane treatment step in the acid injection portion 4. Specifically, the acid B is supplied through the acid injection pipe 4a to the pipe that supplies the treated water stored in the membrane permeated water storage tank 3b to the reverse osmosis membrane treatment unit 5 described later. At this time, the supply amount of the acid B is adjusted so that the pH of the permeated water after the acid injection becomes a desired value.

  The lower limit of the pH adjustment value of the membrane permeated water in the acid injection step is preferably 5, and more preferably 5.5. On the other hand, the upper limit of the pH adjustment value is preferably 6.5, more preferably 6. If the pH adjustment value is less than the lower limit, the reverse osmosis membrane 5a may be deteriorated by the acid B and the rejection may be lowered. On the other hand, if the pH adjustment value exceeds the upper limit, apatite becomes difficult to dissolve in the membrane permeated water, and the effect of inhibiting clogging of the reverse osmosis membrane 5a due to acid injection may be insufficient.

<Reverse osmosis membrane treatment process>
In the reverse osmosis membrane treatment step, the reverse osmosis membrane treatment unit 5 separates the membrane permeated water after the acid injection step with the reverse osmosis membrane 5a. Specifically, the membrane permeated water is pumped to the reverse osmosis membrane 5a using the pump 5d, and the reverse osmosis membrane permeated water that has permeated the reverse osmosis membrane 5a and the concentrated water that has not permeated the reverse osmosis membrane 5a are separated. To do. The reverse osmosis membrane permeated water is stored in the reverse osmosis membrane permeated water storage tank 5b, and the concentrated water is stored in the concentrated water storage tank 5c.

  In addition, the said reverse osmosis membrane permeated water is discharged | emitted out of the system as reused water Z besides being used as backwashing water at the backwashing process mentioned later.

<Neutralization process>
In the neutralization step, the solid concentrate separated in the solid-liquid separation step is neutralized in the neutralization tank 7 using the concentrated water obtained in the reverse osmosis membrane treatment step. Specifically, the concentrated water is supplied to the neutralization tank 7 through the flow path 8 to neutralize the solid content concentrate stored in the neutralization tank 7. The neutralized waste water is discharged to the waste water storage tank 10 by the pump 7a.

  In addition, the waste_water | drain discharged | emitted by the waste_water | drain storage tank 10 is mixed with some phosphorus containing hard water X as needed, and is discharged | emitted out of the system as the discharge water Y by the pump 10a.

<Back washing process>
In the reverse washing step, the filtration membrane 3a is reverse washed with the reverse osmosis membrane permeated water obtained in the reverse osmosis membrane treatment step using the reverse washing mechanism 6. Specifically, a filtration membrane using the reverse osmosis membrane permeated water in the reverse osmosis membrane permeated water storage tank 5b as washing water through the washing water supply pipe 6a by a pump 6c disposed in the reverse osmosis membrane permeated water storage tank 5b. This is done by supplying the container 3a. The washing water after washing the filter membrane 3a is discharged to the neutralization tank 7 through the washing water discharge pipe 6b.

  The filtration membrane 3a may be washed by the reverse washing mechanism 6 when, for example, the continuous filtration time of the filtration membrane 3a reaches a certain time, or when the differential pressure of the filtration membrane 3a becomes a certain value or more. Also good. In the case where the continuous filtration by the filtration membrane 3a and the back washing process are alternately performed, the interval for performing the back washing process is preferably, for example, 20 minutes or more and 50 minutes or less. In the reverse cleaning step, air such as bubbles may be rubbed into the filtration membrane 3a in addition to cleaning with cleaning water.

[Second Embodiment]
The said purification method is a purification method of the phosphorus containing high hardness water X containing a hardness component and phosphoric acid. The purification method mainly includes an apatite production step, a sedimentation separation step, a solid-liquid separation step, a membrane treatment step, an acid injection step, a reverse osmosis membrane treatment step, a neutralization treatment step, and a reverse washing step. Prepare for.

  For the purification method, for example, a purification device shown in FIG. 4 is used. The purification device of FIG. 4 is a purification device of phosphorus-containing high hardness water X containing a hardness component and phosphoric acid. The purification apparatus includes an apatite generation unit 1, a solid-liquid separation unit 2, a membrane treatment unit 3, an acid injection unit 4, a reverse osmosis membrane treatment unit 5, a reverse cleaning mechanism 6, and a neutralization tank 7. Prepare mainly. Furthermore, the purification device has a flow path 8 for supplying concentrated water obtained by the reverse osmosis membrane treatment unit 5 to the neutralization tank 7. In addition, the purification device further includes a sedimentation separation unit 16 that precipitates and separates the organic matter W contained in the phosphorus-containing high-hardness water X by the flocculant E between the apatite generation unit 1 and the solid-liquid separation unit 2.

  In the purification method and the purification apparatus, by adding the flocculant E, the organic matter W in the phosphorus-containing high-hardness water X aggregates with apatite as the core. By sedimenting and separating the agglomerated organic matter W, the organic matter W adhering to the membrane surface during the membrane treatment can be reduced, so that the clogging of the filtration membrane 3a can be further reduced.

[Purification device]
The said purification apparatus discharge | releases the reuse water Z out of the system which contains the phosphorus containing high hardness water storage part 9 which stores the phosphorus containing high hardness water X temporarily, the waste water storage tank 10 which stores the discharge water Y temporarily. A pump 11 is further provided.

  Since the structure except the sedimentation separation part 16 is the same as that of the purification apparatus shown in FIG. 1 among the structures of the said purification apparatus, the same code | symbol is attached | subjected and description is abbreviate | omitted. Hereinafter, the sedimentation separation unit 16 will be described.

<Sediment separation part>
The sedimentation separation unit 16 includes a sedimentation separation tank 16 a that supplies the flocculant E to the treated water treated by the apatite generation unit 1 and separates the organic matter W by sedimentation. The sedimentation separation unit 16 includes a supernatant liquid discharge pipe 16b that discharges the supernatant of the treated water in which the organic matter W is settled to the solid-liquid separation unit 2, and a sediment discharge pipe that discharges the settled organic substance W to the outside of the system. 16c.

  As the settling separation tank 16a, for example, a settling separation tank provided with a cylindrical supply portion to which the treated water and the flocculant E are supplied and a funnel-shaped bottom portion that is connected to the lower portion of the supply portion and protrudes downward in the center. Can be used. The sedimentation tank 16a has a discharge port for discharging the supernatant in the supply unit, and a recovery port capable of recovering the organic matter W at the tip of the funnel-shaped bottom. The supernatant discharge pipe 16b is connected to the discharge port, and the sediment discharge pipe 16c is connected to the recovery port.

  As the flocculant E, aluminum-based inorganic flocculants such as sulfuric acid band (aluminum sulfate) and PAC (polyaluminum chloride), iron-based inorganic flocculants such as polyiron and ferric chloride, and the like can be used. Among these, PAC is preferable because the amount added can be easily managed.

  As a minimum of the addition amount of the said flocculant E in the said treated water, 1 ppm is preferable and 2 ppm is more preferable. On the other hand, the upper limit of the addition amount of the flocculant E is preferably 20 ppm, and more preferably 10 ppm. There exists a possibility that the removal effect of the organic substance W may become inadequate that the addition amount of the said coagulant | flocculant E is less than the said minimum. On the contrary, when the addition amount of the flocculant E exceeds the upper limit, the pH of the treated water tends to be lowered, and the apatite is dissolved and the filtration membrane 3a is likely to be clogged.

[Purification method]
Next, a purification method using the purification device will be described. Of the steps of the purification method, the steps other than the sedimentation separation step are the same as the steps of the purification method using the purification apparatus shown in FIG.

<Sediment separation process>
In the sedimentation separation process, the treated water after the apatite production process is sedimented and separated in the sedimentation separation unit 16. This sedimentation separation step is performed after the apatite production step and before the solid-liquid separation step. Specifically, the coagulant | flocculant E is supplied to the sedimentation tank 16a with the treated water after an apatite production | generation process. By adding the flocculant E, the organic matter W in the phosphorus-containing high-hardness water X aggregates with apatite as the core. The agglomerated organic matter W settles in the sedimentation tank 16a and is discharged out of the system through the sediment discharge pipe 16c. On the other hand, the supernatant in the sedimentation / separation tank 16a from which the agglomerated organic matter W is separated is sent to the solid-liquid separation unit 2 via the supernatant discharge pipe 16b.

[Other Embodiments]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not limited to the configuration of the embodiment described above, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims. The

  In the above embodiment, the case where the cleaning method includes the acid injection step has been described. However, the acid injection step is not an essential constituent element. For example, when the apatite is sufficiently separated in the solid-liquid separation step, the acid injection step is performed. It may be omitted. When the acid injection step is not performed, the acid injection portion of the cleaning device can be omitted.

  Further, the reverse osmosis membrane treatment step can be omitted. Even in this case, the acid injection step can be omitted. Moreover, the acid injection | pouring part and reverse osmosis membrane process part of a washing | cleaning apparatus are also omissible.

  In the above embodiment, the case where the reverse osmosis membrane permeated water obtained in the reverse osmosis membrane treatment step is used as it is for reverse cleaning has been described. However, further acid is injected into the reverse osmosis membrane permeated water and used as the cleaning water. Also good. Thus, the apatite adhering to the filtration membrane can be more effectively removed by lowering the pH of the washing water. In addition, the pH of the washing water after the acid injection is preferably 4 or more and 5 or less from the viewpoints of deterioration of the filtration membrane due to the acid and inhibition of the reduction of the blocking rate and the effect of improving the washing power.

  Moreover, it is not essential to use the reverse osmosis membrane permeated water obtained in the reverse osmosis membrane treatment step for back washing. For example, external water or treated water stored in a membrane permeated water storage tank may be used as the washing water. . Even when external water or the like is used as the washing water, it is preferable to inject an acid to lower the pH of the washing water. In addition, a switching valve may be provided so that, for example, reverse osmosis membrane permeated water and treated water stored in the membrane permeated water storage tank may be used selectively or mixed.

  In the said embodiment, although the solid content concentrate isolate | separated in the solid-liquid separation part demonstrated the case where it neutralizes with a neutralization tank using the concentrated water obtained in a reverse osmosis membrane process part, using concentrated water For example, the acid may be directly injected into the neutralization tank. When concentrated water is not used for neutralization in the neutralization tank, the flow path for supplying the concentrated water to the neutralization tank can be omitted. In this case, the concentrated water is discharged to, for example, a drainage storage tank.

  In the above embodiment, the case where the apatite is separated by the solid-liquid separation unit has been described. However, the apatite may be separated by the apatite generation unit in addition to the separation by the solid-liquid separation unit. For example, sedimentation separation can be used as a method of separation in the apatite generation unit. Moreover, the apatite separated in the apatite production part is discharged out of the system.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

[No. 1]
Phosphorus-containing high-hardness water (raw water) was purified by a method for purifying phosphorus-containing high-hardness water using the purification apparatus of FIG. Table 1 shows the quality of raw water. In the purification apparatus of FIG. 1, sodium hydroxide was used as a pH adjuster in the apatite generation unit. Moreover, the filtration membrane provided in a membrane treatment part used the filtration membrane made from polytetrafluoroethylene (PTFE). Hydrochloric acid was used as the acid in the acid injection part.

<Evaluation of pH adjustment value>
In the purification apparatus of FIG. 1, the operating flux is fixed at 50 LMH, and the pH adjustment value in the apatite generation process is changed by adjusting the supply amount of sodium hydroxide as a pH adjusting agent, and the differential pressure of the filtration membrane at that time (TMP) was measured. The results are shown in FIG. Since the pH value of the treated water hardly changes in the solid-liquid separation process, the pH adjustment value in the apatite production process is substantially equal to the pH value of the treated water supplied to the filtration membrane.

  As can be seen from the graph of FIG. 5, the differential pressure of the filtration membrane can be reduced by setting the pH adjustment value in the apatite generation step to 8.25 or more and 9.5 or less. It turns out that the removal efficiency of the calcium and phosphoric acid from phosphorus containing high hardness water can be raised by making pH adjustment value in the said range, and the clogging of a filtration membrane can further be reduced.

<Water quality evaluation of treated water>
The quality of the treated water in each process when the operating flux was 50 LMH and the pH adjustment value in the apatite production process was 8.3 was measured. The results are shown in Table 1.

  In Table 1, TC is the total carbon content (Total Carbon), IC is the inorganic carbon content (Inorganic Carbon), TOC is the total organic carbon content (Total Organic Carbon), and DOC is the dissolved organic carbon content (Dissolved Organic Carbon), respectively. Represent.

As can be seen from Table 1, calcium ions and phosphate ions are greatly reduced after the apatite production step. Moreover, when the substance adhering to the filter membrane surface was analyzed by FT-IR, a peak considered to be hydroxyapatite (HAP) was observed in the vicinity of 1100 cm ⁻¹ . From the above, it can be seen that apatite is produced by calcium and phosphoric acid contained in the phosphorus-containing high-hardness water by adjusting the pH, and the hardness component and phosphoric acid contained in the treated water that is subjected to membrane separation in the membrane treatment step can be reduced.

<Comparison of HAP generation effect>
Using the purification apparatus of FIG. 1, the case where apatite generation was performed with a pH adjustment value of 8.5 in the apatite generation step was compared with the case where no pH adjusting agent was supplied, that is, apatite generation was not performed. The comparison was performed by measuring the differential pressure of the filtration membrane when the operating flux was changed in the range of 30LMH to 60MLH. The results are shown in FIG.

  As can be seen from the graph of FIG. 6, the differential pressure of the filtration membrane is lower when pH is adjusted and apatite is generated in any operating flux than when apatite is not generated. This shows that clogging of the filtration membrane can be reduced by adjusting the pH of the phosphorus-containing high-hardness water to produce apatite with calcium and phosphoric acid contained in the phosphorus-containing high-hardness water.

<Evaluation of power consumption>
Furthermore, the electric power consumed by the filtration membrane was calculated and compared for the case where the apatite generation step was performed and the case where it was not performed. In calculating the power consumption, the amount of treated water was 10000 m ³ / day, the supply pressure was 100 kPa, the pump efficiency was 83%, and the power consumption per unit amount of treated water was determined using the following formula. The results are shown in Table 2.
P = ρ × g × Q × H / (10 × η) (1)
here,
P: Power consumption of pump (kW)
ρ: density of treated water (1000 kg / m ³ )
Q: Flow velocity (m ³ / s)
H: Pump head (m)
η: Pump efficiency (%)
g: Gravitational acceleration (9.8 m / s ² )

  From the results in Table 2, it can be seen that by producing apatite, clogging of the filtration membrane is reduced, and power consumption can be reduced by 20% or more.

[No. 2]
Next, phosphorus-containing high hardness water (raw water) was purified by a method for purifying phosphorus-containing high hardness water using the purification apparatus of FIG. No. The same as 1 was used. PAC was used as the flocculant in the sedimentation separation unit, and the amount added was 10 ppm. Regarding the pH adjusting agent in the apatite production part, the filtration membrane provided in the membrane treatment part, and the acid in the acid injection part, The same as 1 was used.

<Evaluation>
The operating flux was purified to 50 LMH, and the pH adjustment value in the apatite production process was set to 8.3. Comparison with 1 was performed. The results are shown in Table 3.

  In Table 3, “-” in the case of adding a flocculant indicates that no flocculant is added.

  From Table 3, no. The TOC before solid-liquid separation of No. 2 It can be seen that it is smaller than the TOC before 1 solid-liquid separation. This shows that organic substances can be effectively removed from the treated water by adding a flocculant after apatite formation.

  No. In No. 1, when the operation was performed while backwashing 8 times a day, the pressure difference of membrane filtration reached 70 kPa in 3 weeks, and chemical cleaning was required. In contrast, no. In No. 2, even when backwashing was performed four times a day, the differential pressure of membrane filtration after one month was 50 to 60 kPa, and stable operation was possible.

  From this, it is possible to reduce the organic matter adhering to the membrane surface in the membrane treatment section by aggregating and separating the organic matter in the phosphorus-containing high-hardness water by adding a flocculant after the apatite is formed. It can be seen that clogging can be further reduced.

  As described above, by using the method and apparatus for purifying phosphorus-containing high-hardness water according to the present invention, it is possible to stably operate the water treatment facility and reduce power consumption by reducing clogging of the filtration membrane.

DESCRIPTION OF SYMBOLS 1 Apatite production | generation part 1a Pump 1b Stirrer 1c pH measuring device 2 Solid-liquid separation part 2a Solid-liquid separation apparatus 2b Solid-liquid separation treated water storage tank 2c Solid content concentrate discharge pipe 3 Membrane treatment part 3a Filtration membrane 3b Membrane permeated water storage Tank 3c Pump 4 Acid injection part 4a Acid injection pipe 5 Reverse osmosis membrane treatment part 5a Reverse osmosis membrane 5b Reverse osmosis membrane permeated water storage tank 5c Concentrated water storage tank 5d Pump 6 Reverse washing mechanism 6a Washing water supply pipe 6b Washing water discharge pipe 6c Pump 7 Neutralization tank 7a Pump 8 Flow path 9 Phosphorus-containing high hardness water reservoir 9a Phosphorus-containing high hardness water reservoir 9b Pump 10 Drainage reservoir 10a Pump 11 Pump 12 Mixing tank 13 Inline mixer 14 Bubble supply mechanism 15 Aeration tank 16 Sedimentation separation part 16a Sedimentation separation tank 16b Supernatant discharge pipe 16c Sediment discharge pipe A pH adjuster B Acid C Air D Bubble E Flocculant W Organic substance X Phosphorus containing high hardness Y discharge water Z recycled water

Claims (14)

A method for purifying phosphorus-containing high hardness water containing a hardness component and phosphoric acid,
An apatite production step of producing apatite by adjusting the pH of the phosphorus-containing high hardness water;
A solid-liquid separation step for solid-liquid separation of the treated water after the apatite production step;
A method for purifying phosphorus-containing high-hardness water, comprising: a membrane treatment step of membrane separation of the treated water separated in the solid-liquid separation step with an ultrafiltration membrane or a microfiltration membrane.   The method for purifying phosphorus-containing high hardness water according to claim 1, further comprising a sedimentation separation step of precipitating and separating organic matter contained in the phosphorus-containing high hardness water with a flocculant after the apatite generation step and before the solid-liquid separation step. .   The method for purifying phosphorus-containing hard water according to claim 1 or 2, wherein the apatite is hydroxyapatite.   The method for purifying phosphorus-containing high-hardness water according to claim 1, wherein the pH adjustment value in the apatite production step is 8.25 or more and 9.5 or less. An acid injection step of injecting an acid into the membrane permeated water obtained in the membrane treatment step;
The method for purifying phosphorus-containing high hardness water according to any one of claims 1 to 4, further comprising: a reverse osmosis membrane treatment step of separating the membrane permeated water after the acid injection step with a reverse osmosis membrane.   The method for purifying phosphorus-containing hard water according to claim 5, wherein the pH adjustment value of the membrane permeated water in the acid injection step is 5 or more and 6.5 or less.   The phosphorus-containing high-hardness water according to claim 5 or 6, further comprising a reverse washing step of reverse washing the ultrafiltration membrane or the microfiltration membrane with the reverse osmosis membrane permeated water obtained in the reverse osmosis membrane treatment step. Purification method. A device for purifying phosphorus-containing high hardness water containing a hardness component and phosphoric acid,
An apatite generating part that generates apatite by adjusting the pH of phosphorus-containing high hardness water;
A solid-liquid separation unit for solid-liquid separation of the treated water that produced apatite in the apatite production unit;
A device for purifying phosphorus-containing high hardness water, comprising: a membrane treatment unit for separating the treated water from which the solid content has been separated by the solid-liquid separation unit with an ultrafiltration membrane or a microfiltration membrane.   The purification of phosphorus-containing high-hardness water according to claim 8, further comprising a sedimentation separation part that precipitates and separates organic matter contained in the phosphorus-containing high-hardness water with a flocculant between the apatite generation part and the solid-liquid separation part. apparatus. An acid injection unit for injecting acid into the membrane permeated water obtained in the membrane treatment unit;
The apparatus for purifying phosphorus-containing hard water according to claim 8 or 9, further comprising: a reverse osmosis membrane treatment unit that separates the membrane permeated water into which the acid has been injected by the acid injection unit with a reverse osmosis membrane. A neutralization tank for neutralizing the solid content concentrate separated in the solid-liquid separation unit,
The apparatus for purifying phosphorus-containing hard water according to claim 10, further comprising a flow path for supplying concentrated water obtained in the reverse osmosis membrane treatment section to the neutralization tank.   The phosphorus-containing high hardness water according to claim 10 or 11, further comprising a reverse cleaning mechanism for reverse cleaning the ultrafiltration membrane or the microfiltration membrane with reverse osmosis membrane permeated water obtained in the reverse osmosis membrane treatment unit. Purification equipment. The apatite generation part has a pump for supplying a pH adjusting agent, and a stirring device for stirring the pH adjusting agent,
The purification apparatus for phosphorus-containing high-hardness water according to any one of claims 8 to 12, wherein the stirring device includes an in-line mixer or an aeration tank. The apparatus for purifying phosphorus-containing hard water according to claim 13, wherein the pH adjuster is sodium hydroxide.

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