TW201400421A - Water treatment method and water treatment device - Google Patents

Abstract

Provided are a water treatment method and water treatment device capable of increasing the water quality of waste water without the use of chemical agents. (a) Either a sedimentation separation method or a centrifugal separation method is used to sort the inorganic particles contained in raw water into a first particle group and a second particle group such that the average particle diameter of the first particle group is greater than the average particle diameter of the second particle group, and by this means, said raw water is divided into two parts, first waste water containing the first particle group, and second waste water containing the second particle group. (b) First, the first waste water is sent to a solid-liquid separation device having a filter, and the inorganic particles of the first particle group are deposited on the filter. (c) After step (b), the second waste water is sent to the solid-liquid separation device, and the inorganic particles of the second particle group are deposited on the filter. By this means, a precoat layer which includes the inorganic particles of the first and second particle groups is formed on the filter. (d) The precoat layer is scraped from the filter, and the scraped substance is discharged from the solid-liquid separation device.

Description

Water treatment method and water treatment device

The embodiment described herein relates to a water treatment method and a water treatment apparatus for separating inorganic particles present in water.

Recently, with the development of industry or the increase in population, more and more efficient use of water resources has been required. For this reason, the reuse of drainage such as industrial drainage becomes very important. In order to achieve these goals, purification of water, that is, separation of other substances from water, is required. Various methods have been known as methods for separating other substances from liquids, and examples thereof include a membrane separation method, a centrifugal separation method, an activated carbon adsorption method, an ozone treatment method, and a flocculating matter by flocculation. Removal method, etc. By such methods, it is possible to remove chemical substances having a large influence on the environment such as fluorine, chlorine, phosphorus, and nitrogen contained in the water, or to remove oils or clays dispersed in the water. Among these, the membrane separation method is one of the most commonly used methods for removing insoluble matter in water.

In factories such as semiconductor manufacturing plants, LCD manufacturing plants, and crystal processing plants, it is necessary to use a large amount of waste water containing a water-soluble fluorine compound such as HF or H ₂ SiF ₆ as a factory drainage. Therefore, it is necessary to make it harmless. deal with. As a method of removing a fluorine component from fluorine-containing wastewater, a method of reacting with a calcium agent and separating it as a fluorine compound has been known. For example, Japanese Laid-Open Patent Publication No. 2010-207755 (Patent Document 1) discloses a method in which fluoride ions in water are precipitated in water as calcium fluoride, and polyaluminum chloride (PAC) or the like is added thereto. A flocculating agent is a method in which calcium fluoride is flocculated and further grown into a bulk state to be separated and recovered.

However, the conventional method is difficult to reduce the purity of the separated and recovered calcium fluoride and recover it as a valuable substance. Further, the conventional method has a problem that the amount of sludge generated by the amount of the polymer flocculant added is increased, so that the cost of disposal is increased. Moreover, such a calcium fluoride-containing drainage system often contains fine calcium fluoride, and it is very difficult to remove it by using a solid-liquid separation device such as filtration.

The embodiment described herein has been developed to solve the above problems, and an object of the invention is to provide a water treatment method and a water treatment device which can improve the quality of drainage water without using a chemical.

The water treatment method according to the embodiment described herein is characterized in that: (a) one of a sedimentation separation method or a centrifugal separation method is used, wherein the average particle diameter of the first particle group is larger than the average of the second particle group. Particle size The inorganic material particles contained in the raw water are classified into the first particle group and the second particle group, whereby the raw water can be divided into a first water containing the first particle group and a second water containing the second particle group. (b) feeding the first drainage first to the solid-liquid separation device having the filter, and depositing the inorganic particles of the first particle group on the filter; (c) in the step (b) After that, the second drainage is sent to the solid-liquid separation device, and the inorganic particles of the second particle group are deposited on the filter, thereby pre-coating the inorganic particles having the first and second particle groups. Formed on the filter; (d) peeling the pre-coating layer from the filter, and discharging the exfoliated material from the solid-liquid separating device.

1‧‧‧Water treatment unit

2, 2A‧‧‧ reaction tank (filled tower)

3‧‧‧ original sink

4‧‧‧Additive Addition Device

5‧‧‧Settling separation tank (grading means)

6‧‧‧With large particle drainage tank (1st temporary storage tank)

7‧‧‧Small particle drainage tank (2nd temporary storage tank)

8‧‧‧Solid-liquid separation device

9‧‧‧Cyclone (grading means)

10‧‧‧Processing sink

11‧‧‧ concentrate tank

22, 23‧‧‧ Hard particles (CaF ₂ particles, etc., pre-coating)

24‧‧‧Stacked layer (pre-coating)

26‧‧‧soft particles

51‧‧‧Baffle

52‧‧‧Inflow side space

53‧‧‧Drainage side space

54‧‧‧lower opening

81‧‧‧Upper space

82‧‧‧Lower space

83‧‧‧Filter

84‧‧‧Micropores

91‧‧‧ Container

P1 to P3‧‧ pump

V1 to V2‧‧‧ valve

L1‧‧‧ raw water supply pipeline

L2‧‧‧1st drainage discharge line

L3‧‧‧2nd drainage discharge line

L4‧‧‧2nd drainage supply line

L5‧‧‧1st drainage supply line

L6‧‧‧Processing water supply pipeline

L7‧‧‧ Stripped water supply pipeline

L8‧‧‧ Concentrate supply pipeline

D1‧‧‧Average particle size of large particles

d2‧‧‧Average particle size of small particles

Df‧‧‧diameter

d _L ‧‧‧Average particle size

△d‧‧‧Difference

Fig. 1 is a block diagram showing the configuration of a water treatment apparatus according to an embodiment.

Fig. 2 is a process diagram showing an outline of a water treatment process using the apparatus of Fig. 1.

Fig. 3A is a schematic cross-sectional view showing a state in which water containing the first particles is supplied to the filter.

Fig. 3B is a schematic cross-sectional view showing a pre-coat layer composed of the first particles deposited on the filter.

Fig. 3C is a schematic cross-sectional view showing a state in which water containing the second particles is supplied to the precoat layer on the filter.

Fig. 3D is a schematic cross-sectional view showing a pre-coat layer composed of first and second particles deposited on a filter.

Figure 3E shows the appearance of the pre-coat layer being removed from the filter. intention.

Fig. 4A is a schematic cross-sectional view showing a state in which water containing soft particles is supplied to a filter.

Fig. 4B is a schematic cross-sectional view showing the state in which the soft particles after deformation occlude the pores of the filter.

Fig. 4C is a schematic cross-sectional view showing a state in which the soft particles after clogging cannot be easily removed from the filter by washing with water.

Fig. 5 is a block diagram showing the construction of a water treatment apparatus according to another embodiment.

Fig. 6 is a process diagram showing an outline of a water treatment process using the apparatus of Fig. 5.

Fig. 7 is a block diagram showing the construction of a water treatment apparatus according to another embodiment.

Fig. 8 is a process diagram showing an outline of a water treatment process using the apparatus of Fig. 7.

Hereinafter, various embodiments for solving the above problems will be described.

(1) The water treatment method according to the embodiment described herein, characterized in that: (a) one of a sedimentation separation method or a centrifugal separation method is used, wherein the average particle diameter of the first particle group becomes larger than the second particle a method of classifying the inorganic particles contained in the raw water into the first particle group and the second particle group, whereby the raw water can be divided into the first water containing the first particle group and including the foregoing The second drainage of the second particle group (b) sending the first drainage first to the solid-liquid separation device having the filter, and depositing the inorganic particles of the first particle group on the filter; (c) after the step (b) The second drainage is sent to the solid-liquid separation device, and the inorganic particles of the second particle group are deposited on the filter, thereby precoating the inorganic particles having the first and second particle groups (precoat) And forming a filter on the filter; (d) peeling off the pre-coating layer from the filter, and discharging the peeling material from the solid-liquid separating device.

In the embodiment described above, first, the inorganic particles in water are roughly classified into two particle groups according to the particle diameter, and the first particle group having a large average particle diameter is first sent to the solid-liquid separation device. The first particle group (Fig. 3A and Fig. 3B) is filtered by a filter. Next, the second particle group having a small average particle diameter is sent to the solid-liquid separator, and the second particle group (Fig. 3C and 3D) is filtered by a filter. Thereby, the inorganic particles composed of the first and second particle groups are deposited on the filter of the solid-liquid separation device, and a deposition layer having a two-layer structure is formed. Then, the stripping water is blown from the side of the solid-liquid separation device to the deposition layer of the second layer, and the deposited layer is peeled off from the filter and decomposed into discrete states, and the inorganic particles (decomposed products of the deposit) are separated from the stripped water. It is discharged from the solid-liquid separation device (Fig. 3E).

When the inorganic particles to be removed are divided into two groups and individually filtered by a solid-liquid separation device, various advantages described below are obtained.

First, the large particles are first layered on the filter than the small particles, and a pre-coating layer of large particles is formed, so that the small particles do not directly contact the filter. By filtering the surface, it is possible to avoid clogging of the filter due to small particles, so that the life of the filter can be extended (the filter life is extended). Second, since large particles are first laminated on the filter than small particles, a filter having pores having a large pore size can be used. By using such a filter, the pressure loss of the water supply pressure of the filter can be reduced, and the increase in the amount of treated water (increased processing efficiency) can be estimated. Third, since large particles are first deposited on the filter than small particles, the pores between the particles having large particles are trapped to capture small particles, so that particles smaller than the diameter of the actual filter pores can be captured. (increased removal rate).

(2) In the above (1), in the classification step (a), the raw water can be divided into the first drainage and the second drainage using the sedimentation separation method (Fig. 1, Fig. 2, Fig. 7, Fig. 8). .

The term "sedimentation separation method" is defined as the method of separating the solid matter into a large mass and a small mass by utilizing the difference in the sedimentation velocity in the water. As means for utilizing the sedimentation separation method, a sedimentation separation tank having a baffle plate inside, or a cascade-shaped precipitator or sedimentation tank can be cited. By using a separation method using the mechanics of such gravity action, the inorganic particles in the water can be classified into the first particle group and the second particle group with less energy consumption.

(3) In the above (1), in the classification step (a), the raw water may be divided into the first drainage water and the second drainage water (Fig. 5 and Fig. 6) by a centrifugal separation method.

The "centrifugal separation method" is defined as a method of separating a solid matter into a large mass and a small mass by the action of centrifugal force. As a use The means of the centrifugal separation method may be a liquid cyclone having an inverted conical stepped body portion and a lowermost pot. The lowermost container means a portion that is attached to the lowermost portion of the liquid cyclone and that allows the heavier components after centrifugation to flow down. The heavier component concentrated in the lowermost container is in the form of a slurry. By using such a mechanical separation method, inorganic particles in water can be classified into the first particle group and the second particle group quickly and efficiently.

(4) In the above (1), it is preferable that the difference Δd between the average particle diameters of the inorganic particles of the first particle group and the inorganic particles of the second particle group in the classification step (a) is The average particle diameter d _L of the inorganic particles of the first particle group is in the range of more than 6% and 50% or less (0.06 d _L < Δd ≦ 0.50 d _L ).

In the classification of the inorganic particles in the water, the difference Δd between the average particle diameters of the inorganic particles of the first and second particle groups contained in the two drainages is set to the average particle size of the inorganic particles in the first particle group. When the diameter d _{L is in the range} of more than 6% and 50% or less, the water treatment can be performed efficiently. When the difference Δd of the average particle diameter is 6% or less, there is no advantage in that the first particle group and the second particle group are not separately separated and filtered. On the other hand, when the difference Δd of the average particle diameter exceeds 50%, it is feared that the small particles of the second particle group pass between the first particle group after the large particles are deposited on the filter and pass through the filter. The reason for this. As a result of repeating various reviews, the inventors of the present invention have confirmed that the particle diameter obtained by layering any of the particles is approximately 6% of the particle.

(5) In the above (1), preferably, the filter system of the solid-liquid separation device It has a filter surface that is orthogonal to the direction of gravity.

This is when the filter surface of the filter is orthogonal to the direction of gravity, even if the filter surface of the filter is horizontal, since the particles deposited on the filter are in a stable state due to gravity, the particles are substantially on the filter. It does not move, but maintains a uniform thickness of the pre-coating layer and improves the quality of the treated water after passing through the filter.

(6) In the above (1), before the classification step (a), there is further provided a pretreatment step of adding a calcium-containing filter aid to the raw water to dissolve the calcium-containing filter aid in the water to produce a cation ( Ca ²⁺ ) reacts with the anion (F ⁻ ) in the raw water, and precipitates particles of the reaction compound as inorganic particles (Fig. 1, Fig. 2, Fig. 5, Fig. 6).

In the treatment step, a calcium-containing filter aid (first particles) is added to the raw water containing fluorine ions, and particles (second particles) of the fluorine compound are precipitated by reacting the fluoride ions with the components of the calcium-containing filter aid. By forming the precipitated particles, the specific gravity of the inorganic particles (second particles) is relatively increased, and the gravity sedimentation separation of the sedimentation separation tank or the centrifugal separation of the cyclone is facilitated. The drainage containing the precipitated compound particles as the second particles is sent to a sedimentation separation tank or a cyclone, and can be classified into a first particle group having a large average particle diameter and a second particle having a small average particle diameter in a sedimentation separation tank or a cyclone. group.

(7) In the above (6), in the pretreatment step, fine powder of calcium carbonate may be added to the raw water as the calcium-containing filter aid, and the fluoride ion contained in the raw water may be precipitated as calcium fluoride particles. (Table 1, Table 2).

In the pretreatment step, fine powder of calcium carbonate is added as the first particles in the water to be treated of the fluorine-containing ions, and calcium fluoride particles are precipitated.

The calcium carbonate added is dissolved in water, and calcium ions and carbonate ions are generated as in the following formula (1).

CaCO ₃ →Ca ²⁺ +CO ₃ ^2- ...(1)

The generated calcium ions react with fluoride ions in the drainage, and calcium fluoride is precipitated according to the following formula (2). Incidentally, the average particle diameter of the calcium fluoride particles precipitated in water is about 0.5 μm to 2 μm.

Ca ²⁺ +2F ^- →CaF ₂ ↓...(2)

The treated water containing precipitated calcium fluoride particles (specific gravity 3.18) is sent to a sedimentation separation tank or a cyclone, and is classified into a first particle group having a large average particle diameter and a small average particle diameter in a sedimentation separation tank or a cyclone. The second particle group.

(8) In the above (7), it is preferred that the fine powder of calcium carbonate is composed of particles having an average particle diameter of 4 μm to 30 μm (Table 1, Table 2).

The average particle diameter of the calcium carbonate fine powder is preferably in the range of approximately 4 μm to 30 μm. This is because the average particle diameter of the calcium fluoride particles produced is approximately in the range of 0.5 μm to 2 μm. Therefore, as long as calcium carbonate fine powder having a large average particle diameter is used, calcium fluoride particles cannot be deposited on the carbonated carbon dioxide. It is above the pre-coating layer composed of calcium particles.

(9) The water treatment device according to the embodiment of the present invention, characterized in that: (A) classification means 5 and 9 are the average particle diameter of the first particle group of the inorganic particles contained in the raw water. Be larger than the second particle group The first particle group and the second particle group are classified into a first particle group and a second particle group, and the raw water is divided into a first water containing the first particle group and a second water containing the second particle group. And the (B) solid-liquid separation device 8 is a filter 83 having a filter surface orthogonal to the direction of gravity, and is partitioned into upper and lower by the filter, and has an upper space 81 and a lower space 82. The upper space 81 is configured such that the first and second drainage materials are respectively guided from the classification means to the filter, and the lower space 82 is adapted to pass water passing through the filter; and (C) The drain supply lines L3, L4, and L5 are provided between the classification means and the solid-liquid separation means, and the first and second drains are respectively passed; and (D) the first temporary storage tank 6, Provided in the drainage supply line, and temporarily storing the first drainage from the classification means; and (E) the second temporary storage tank 7 provided in the drainage supply line and temporarily storing the classification means The aforementioned second drainage; (F) the switching valve V3, which is disposed in the drainage system supply line, and the drain communicating with the supply line of the solid-liquid separation device to switch between the first groove and temporarily storing the second temporary storage tank.

In the embodiment described herein, after classifying the inorganic particles in the water by a classification means such as a sedimentation separation tank or a cyclone, the time interval between the first drainage and the second drainage is set by the classification means. Timing is introduced into the solid-liquid separation device, whereby a layer of a two-layer structure composed of the first particle group and the second particle group can be formed on the filter.

(10) In the above (9), it is preferable that the classification means separates the inorganic particles into the sedimentation of the first particle group and the second particle group by the action of gravity. Separation tank (Fig. 1 and Fig. 7).

As means for utilizing the sedimentation separation method, a sedimentation separation tank having a baffle inside can be used. The baffle 51 divides the internal space from the uppermost portion to the lower portion (excluding the bottom portion) of the settling separation tank 5 into the inflow side space 52 and the discharge side space 53. The baffle 51 is attached to the settling separation tank 5 so that the volume of the discharge side space 53 is larger than the volume of the inflow side space 52. The lower end of the baffle 51 is away from the bottom of the settling separation groove 5, and a lower opening 54 is formed between the bottom of the groove and the lower end of the baffle 51. The intermediate lower opening 54 allows the inflow side space 52 to communicate with the discharge side space 53. The bottom of the sedimentation separation unit 5 has a mortar shape (inverted conical shape).

By using such a mechanical separation device (a sedimentation separation groove having a baffle inside), inorganic particles in water can be classified into a first particle group and a second particle group with less energy consumption.

(11) In the above (9), it is preferable that the classification means is a liquid cyclone that separates the inorganic particles into the first particle group and the second particle group by the action of centrifugal force (Fig. 5).

As a means by the centrifugal separation method, a liquid cyclone having a conical body and a lowermost container can be used. By using such a mechanical separation device (liquid cyclone having a container at the lowermost portion), the inorganic particles in the water can be classified into the first particle group and the second particle group quickly and efficiently.

(12) In the above (9), there may be further provided: a pump and a raw water tank for supplying the wastewater containing fluorine ions as the raw water to the classification means (Fig. 7).

In the embodiment described herein, the raw water is not subjected to pretreatment (pretreatment of fluoride ions in the raw water as a treatment of the fluorinated compound particles), but is directly sent from the raw water tank to the classification means, and is classified by means of classification. The inorganic particles contained in the raw water are directly divided into a first particle group (first drainage) and a second particle group (second drainage).

In the treatment of separating the floating solids (SS) other than the precipitated particles, the raw water tank is directly connected to the classification means, and the raw water is directly pumped from the raw water tank to the classification means by the pump, whereby the flow path of the raw water circulation becomes It is short and can remove inorganic particles from water with less energy consumption.

The details of the embodiment will be further explained.

[Classification process of dividing into two particle groups having different average particle diameters]

In order to divide the particles contained in the wastewater into the first particle group and the second particle group having different average particle diameters, various methods can be used. For example, in the gravity sedimentation method, the difference in the sedimentation velocity of the particles can be utilized in the classification. Further, in the centrifugal separation method, the difference in the moving speed of the particles can be utilized in the classification. Alternatively, magnetic or screen meshes can be utilized in the classification. In the embodiment described herein, it is preferable to use a sedimentation separation method or a centrifugal separation method because the process is not complicated. For example, in the sedimentation separation method, a settling tank such as a thickener can be used. In this case, for example, a fixed settling time can be determined in advance, and fine particles are removed from the supernatant liquid, thereby separating large particles concentrated by the lower portion of the settling tank.

In the centrifugation method, it is also possible to use, for example, a liquid cyclone to The organic particles are divided into first and second particle groups. The liquid cyclone discharges water toward the circumferential direction of the inclined cylindrical body, whereby the particles are largely separated to the lower portion, and the particles are smallly separated to the upper portion. The inorganic particles can be divided into the first and second particle groups by using such a liquid cyclone.

When classifying the inorganic particles in the drainage by the classification means, when the particle diameter ratio of the average particle diameter of the inorganic particles contained in the two drainages is set in the range of 6% to 50%, Water treatment can be performed efficiently. Here, the "particle diameter ratio" means the ratio (100 × d2 / d1) of the average particle diameter d2 of the small particles based on the average particle diameter d1 of the large particles.

This is the case when the particle size ratio is less than 6%, and the small particles pass between the large particles of the pre-coating layer. As a result of repeating various reviews, the inventors have confirmed that the average particle diameter of the particles which can be separated by the precoat layer is 6% of the average particle diameter of the particles constituting the precoat layer. On the other hand, when the particle diameter ratio exceeds 50%, the average particle diameter of the two particle groups is close, and there is no advantage in that filtration is performed individually.

[Solid-liquid separation device]

The solid-liquid separation device may have a filter (membrane) that can filter the first particle group constituting the pre-coat layer. However, it is preferable to use a filter having a horizontal filter surface. When the filter surface is horizontal, it is orthogonal to the direction of gravity, and since the particles constituting the pre-coat layer do not flow on the filter and are in a stable state, the pre-coating layer has excellent filtration performance and can be improved in filtration. Water quality.

The filter can be selected by treating the required water quality of the water, for example, using a degree of air permeability of 30 cc/cm ² ×min to 1500 cc/cm ² ×min. The air permeability is measured by the Frazier method. Specifically, when the filter is composed of a woven fabric (filter cloth), it can be measured by a Frazier-type air permeability tester (trade name) manufactured by Yasuda Seiki Co., Ltd. As the filter, for example, a filter cloth for a dehydrator can be used in total, and examples thereof include pyrene (polypropylene), tetrone (polyester), and nylon (polyamide). Among these, a material having a good peelability of a cake layer is more effective. For example, polypropylene is not only inexpensive, but also has a low differential pressure after recovery of the sludge layer, and has little deterioration, so that it is easy to use in water treatment, and therefore it is preferable. Further, although the filter cloth has various weaves such as plain weave, twilled weave, and satie weave, it is not particularly limited. The air permeability or the weaving method of the filter cloth which is more desirable in use may be appropriately selected in view of the production cost and the like, and is particularly preferably a polypropylene, and is preferably a plain weave. These filter cloths can also be subjected to calender processing if necessary.

[Water treatment method using calcium carbonate particles]

The water treatment method of the embodiment described herein is suitable for removal of fluoride ions in water using calcium carbonate particles. In the mechanism of removal of fluoride ions, the calcium carbonate particles react with fluoride ions in water, and a film of calcium fluoride is formed on the surface of the calcium carbonate particles, and the film is peeled off to become a calcium fluoride fragment, the fragment Separated in water, so that the new exposed surface of the calcium carbonate particles reacts with the fluoride ions in the water to remove the water. Fluoride ion. As a result, the small-sized calcium fluoride particles (fractures) and the large-diameter calcium carbonate coexist in the drainage. When the total amount of the drainage is placed in the filter, since the particle size distribution is wide, in order to capture fine particles, it is necessary to use a filter having a fine pore size. Moreover, since fine particles can block the opening of the filter, the life of the filter is also shortened.

In order to prevent this, among the inorganic particles in the water, the particles having a large particle diameter and the particles having a small particle diameter are separated, and the large particles (the first particle group) are stacked on the filter before the small particles (the second particle group). Thereby, a filter having a coarse mesh can be used, and the life of the filter can be extended. Further, the particles contained in the drainage are separated and laminated on the filter, and the other particles are supplied to the filter and laminated, and the amount of the pre-coated layer finally formed is also reduced. And the overall amount of waste (pre-coating, etc.) can be reduced.

Hereinafter, various embodiments will be described with reference to the drawings.

In the present embodiment, two types of methods, a sedimentation separation method and a centrifugal separation method, are used. However, the apparatus used in each method differs in configuration, and therefore each of them will be described below.

(Water treatment device according to the first embodiment)

First, the water treatment apparatus used in the first embodiment will be described with reference to Fig. 1 .

The water treatment device 1 of the present embodiment is a device using a sedimentation separation method using a sedimentation separation tank (precipitator) as a classification means. The water treatment device 1 includes a reaction tank 2, a raw water tank 3, an additive liquid addition device 4, a sedimentation separation tank 5, a first temporary storage tank 6, a second temporary storage tank 7, and a solid liquid. The separation device 8, the treatment tank 10 and the concentrate tank 11, and the machines and devices are connected to each other by a plurality of piping lines L1 to L8. Various types of pumps P1 to P3, valves V1 to V2, sensors (not shown), and sensors are attached to the piping lines L1 to L8, respectively. The measurement signals from the measuring instruments and the sensors are input to an input unit of a controller (not shown), and control signals are output from the output portions of the controller to the pumps P1 to P3 and the valves V1 to V2, respectively, and the signals are controlled. The action. The entire system of the water treatment apparatus 1 can be collectively controlled by a controller (not shown).

The reaction tank 2 is a pretreatment apparatus for pretreatment of raw water, and raw water containing fluorine ions is introduced from the raw water tank 3, and the calcium powder is filtered as a calcium-containing filter while the raw water is temporarily stored in advance. The auxiliary agent is added to the raw water from the additive adding device 4. In the reaction tank 2, fluoride ions contained in the raw water react with carbonate ions to precipitate calcium fluoride particles. Further, the reaction tank 2 may optionally have a stirring screw.

The sedimentation separation tank 5 is divided into two spaces 52, 53 having different volumes by the baffle 51. In other words, the baffle 51 divides the internal space from the uppermost portion to the lower portion (excluding the bottom portion) of the settling separation tank 5 into the inflow side space 52 and the discharge side space 53. The baffle 51 is attached to the settling separation tank 5 so that the volume of the discharge side space 53 is larger than the volume of the inflow side space 52. The lower end of the baffle 51 is away from the bottom of the settling separation groove 5, and a lower opening 54 is formed between the lower end of the baffle 51 and the bottom of the groove. The intermediate lower opening 54 allows the inflow side space 52 to communicate with the discharge side space 53. Among the upper space of the sedimentation separation tank 5, the space 52 having a small volume is connected to the raw water supply line L1 having the pump P1 and connected to Reaction tank 2. Further, the second drain discharge line L3 is connected to the space 53 having a large volume. Further, the bottom portion of the sedimentation separation portion 5 has a mortar shape (inverted conical shape).

On the other hand, the space below the settling tank 5 is connected to the first drain discharge line L2 having the valve V1. The first drain discharge line L2 is connected to the upper portion of the first temporary storage tank 6, and the first drain stream containing the first particle group is flown down to the first temporary storage tank 6 by the action of gravity.

The solid-liquid separation device 8 is provided with a filter 83 that horizontally partitions the inside into the upper space 81 and the lower space 82. The upper space 81 of the solid-liquid separation device is connected to the first and second temporary storage tanks 6 and 7 by the drainage supply lines L4 and L5 having the pressure feed pump P2. Further, a peeling water supply line L7 and a concentrate discharge line L8 having a pump (not shown) are connected to the side portions of the upper space 81, respectively. The line L8 has a pump P3, and the concentrate (sediment + stripped water) is discharged from the solid-liquid separator 8 to the concentrate tank 11. On the other hand, the lower portion 82 of the solid-liquid separation device is connected to the treated water supply line L6, and the treated water can be sent to the treatment tank 10 through the line L6.

(Water treatment method according to the first embodiment)

Next, a water treatment method according to the first embodiment using the above apparatus will be described with reference to Fig. 2 .

The sedimentation separation method is effective especially in the case where the drainage flow rate of the solid content of the water-insoluble matter is large. In the sedimentation separation method, firstly, a fine powder of calcium carbonate is added to the treated water of the fluorine-containing ions, and the calcium fluoride particles are precipitated. The pretreatment process (step S1) is performed. The amount of the calcium carbonate fine powder is, for example, about 0.6 mol to 1.0 mol for the fluoride ion. The particle diameter of the calcium carbonate fine powder is approximately 4 μm to 30 μm. After the raw water and the calcium carbonate fine powder are placed in the reaction tank 2, the time for which these are sufficiently reacted is stirred. The stirring time is, for example, 5 minutes to 60 minutes.

The calcium carbonate fine powder to be added is dissolved in water, and calcium ions and carbonate ions are generated as in the following formula (1).

CaCO ₃ →Ca ²⁺ +CO ₃ ^2- ...(1)

The generated calcium ions react with the fluoride ions in the drainage, and the calcium fluoride fine particles are precipitated according to the following formula (2). The calcium fluoride particles precipitated in water have an average particle diameter of about 1 μm to 2 μm.

Ca ²⁺ +2F ^- →CaF ₂ ↓...(2)

The water to be treated containing precipitated calcium fluoride particles (specific gravity 3.18) is sent to the sedimentation separation tank 5, and is classified into a first particle group having a large average particle diameter and a second particle group having a small average particle diameter in the sedimentation separation tank 5. (Step S2). That is, in the sedimentation separation tank 5, large particles can be taken out from the lower portion of the sedimentation separation tank 5, and small particles are taken out from the upper portion of the sedimentation separation tank 5. Although the settling time depends on the size of the particles and the sedimentation rate, it is, for example, 15 minutes to 120 minutes. A part of the slurry sent from the reaction tank 2 by the pump P1 is settled by the action of gravity, and is discharged from the lower portion of the tank 5 The liquid of the particles discharges the liquid containing small particles from the upper portion of the tank 5. The first drain containing the first particle group having a large average particle diameter is stored in the first temporary storage tank 6. On the other hand, the second drain containing the second particle group having a small average particle diameter is stored in the second temporary storage tank 7.

Next, the switching valve V2 and the pressure feed pump P2 are respectively operated to supply the first drain water from the first temporary storage tank 6 to the solid-liquid separator 8 (Fig. 3A). The particles of the first particle group are separated from the first water by the filter 83. As a result, as shown in FIG. 3B, the particles 22 of the first particle group having a large particle size distribution are deposited on the filter 83 (step S3). . In the separation step S3 of the first particle group, the supply pressure of the pressure feed pump P2 is adjusted to be in the range of 0.2 MPa to 0.5 MPa. The pump P2 is stopped, and the first particle group separation step S3 is completed.

Next, the switching valve V2 is switched, and the pressure feed pump P2 is restarted to supply the second water discharge from the second temporary storage tank 7 to the solid-liquid separation device 8 (Fig. 3C). The particles of the second particle group are separated from the second water by the filter 83, and as a result, the second particle having the smaller average particle diameter is deposited on the particles 22 of the first particle group on the filter 83. Particles 23 of the particle group (step S4). At this time, the average particle diameter d ₂ of the particles 23 of the second particle group is smaller than the diameter df of the filter pores 84, but as shown in FIG. 3D, the particles are composed of the particles 22 of the first particle group. Particles 23 of the second particle group are deposited on the layer. The precoat layer 24 composed of the particles 22 and 23 of the first and second particle groups can be formed on the filter 83. Even in the separation step S4 of the second particle group, the supply pressure of the pressure feed pump P2 is adjusted to be in the range of 0.2 MPa to 0.5 MPa. The pump P2 is stopped, and the second particle group separation step S4 is completed. Next, as shown in FIG. 3E, the peeling water is blown from the side of the solid-liquid separator 8 to the filter 83, and the pre-coating layer 24 is peeled off and removed from the filter 83 (step S5). In other words, the pre-coating layer 24 can be peeled off from the filter 83 by blowing the peeling water from the side of the solid-liquid separating device 8, and discharged to the tank 11 as a concentrate through the discharge line L8 communicating with the discharge port. . Thereby, the filter 83 is washed and regenerated, and solid-liquid separation can be performed again.

In the above-described embodiment, the precipitated calcium fluoride particles are classified and separated and removed by the pretreatment. However, the target particles are not limited to calcium fluoride particles, and are hard to be elastically deformed. The particles 22, 23 are still capable of being processed.

However, since the soft particles 26 are deformed as shown in Fig. 4B and the filter pores 84 are plugged, the clogging is likely to occur, so that the treatment cannot be performed. That is, since the soft particles 26 in the water discharged from the pressure are deformed and embedded in the pores 84 of the filter, not only the water flow amount is drastically reduced, but also as shown in Fig. 4C, even from the side The side blowing of the peeling water also does not allow the soft particles 26 to be peeled off from the filter 83. As such a soft particle 26, for example, a flocculating polymer or a water-insoluble fat or the like is used.

(Second embodiment) (Device of the second embodiment)

Next, a water treatment apparatus 1A used in the water treatment method of the second embodiment will be described with reference to Fig. 5. In addition, the description of the part which overlaps this embodiment and the above embodiment is abbreviate|omitted.

The water treatment apparatus 1A of the present embodiment uses a centrifugal separation method, and is particularly effective in the case where the flow rate is small or the installation area of the apparatus is narrow. The apparatus 1A of the present embodiment differs from the apparatus 1 of the first embodiment in that the apparatus 1A is provided with a liquid cyclone 9 instead of the sedimentation separation tank 5 as a classification means, and the reaction tank 2A is internally filled with A packed tower of calcium carbonate granules. The liquid cyclone 9 is formed into a hollow inverted conical ladder shape in which the upper portion of the main body is wide and the lower portion is gradually narrowed, and a container 91 for concentrating the separation is installed at the lowermost portion. The container 91 is connected to the upper portion of the first temporary storage tank 6 by a line L2 having a valve V1. When the valve V1 is opened, the slurry containing the separated heavier particles (first particle group) flows down by gravity and is discharged to the first temporary storage tank 6. On the other hand, water and lighter particles (second particle group) are discharged to the second temporary storage tank 7 through a line L3 connected to the upper portion of the cyclone.

The reaction vessel 2A is filled with a granular filler 21 mainly composed of calcium carbonate. When the raw water containing fluorine ions is supplied from the raw water tank 3 to the reaction tank 2A, the fluorine ions (F ^- ) react with the calcium ions (Ca ²⁺ ) eluted from the filler 21 to precipitate particles of calcium fluoride.

(Method of Second Embodiment)

Next, a centrifugal separation method using the above apparatus as the second water treatment method will be described with reference to Figs. 6 and 5.

In the reaction tank 2A, fluorine ions contained in the raw water are reacted with calcium carbonate, and particles of calcium fluoride are precipitated as a pretreatment step (step K1). The separation step K2 of the present embodiment is not only a sedimentation tank but also a liquid cyclone. 9 to carry out. The liquid cyclone 9 is classified into particles having a large particle diameter and small particles (step K2). The water to be treated containing precipitated calcium fluoride particles (specific gravity 3.18) is sent to the liquid cyclone 9, and the water introduced into the liquid cyclone 9 is swirled at a high speed along the inner wall of the cyclone body, and by this time The centrifugal force separates the particles from the water, and the first particle group having a large average particle diameter in the mud state is accumulated in the container 91 below the cyclone. The first particle-containing slurry stored in the lower container 91 is opened by the valve V1 and sent to the first temporary storage tank 6 through the line L2. The opening and closing of the valve V1 can be performed periodically or at any time according to the amount of mud in the container 91.

The first drain containing the first particle group having a large average particle diameter is stored in the first temporary storage tank 6. On the other hand, a particle group having a small average particle diameter flows out from the upper portion of the cyclone 9. The second drain containing the second particle group having a small average particle diameter is stored in the second temporary storage tank 7.

Next, the switching valve V2 and the pressure feed pump P2 are respectively operated to supply the first drain water from the first temporary storage tank 6 to the solid-liquid separator 8 (Fig. 3A). The particles of the first particle group are separated from the first water by the filter 83. As a result, as shown in FIG. 3B, the first particles 22 having a large average particle diameter are deposited on the filter 83, whereby the first particles 22 are formed. Pre-coating layer (step K3). In the separation step S3 of the first particle group, the supply pressure of the pressure feed pump P2 is adjusted to be in the range of 0.2 MPa to 0.5 MPa. The pump P2 is stopped, and the first particle group separation step S3 is completed.

Next, the switching valve V2 is switched, and the pressure feed pump P2 is restarted to supply the second water discharge from the second temporary storage tank 7 to the solid-liquid separation device 8 (Fig. 3C). The second particles are separated from the second water by the pre-coating layer on the filter 83. As a result, the second particles 23 having a small average particle diameter are deposited on the pre-coat layer on the filter 83 (step K4). At this time, the average particle diameter d ₂ of the particles 23 of the second particle group is smaller than the diameter df of the filter pores 84, but the second layer is deposited on the pre-coating layer of the first particles 22 as shown in FIG. 3D. Particle 23. The buildup layer 24 of the two-layer structure composed of the particles 22 and 23 of the first and second particle groups can be formed on the filter 83. Even in the separation step S4 of the second particle group, the supply pressure of the pressure feed pump P2 is adjusted to be in the range of 0.2 MPa to 0.5 MPa. The pump P2 is stopped, and the second particle group separation step S4 is completed. Next, as shown in FIG. 3E, the peeling water is blown from the side of the solid-liquid separator 8 to the filter 83, and the build-up layer 24 of the two-layer structure is peeled off and removed from the filter 83 (step K5). In other words, the buildup layer 24 of the two-layer structure can be peeled off from the filter 83 by blowing the peeling water from the side of the solid-liquid separator 8, and discharged to the tank 11 through the discharge line L8 that communicates with the discharge port. As a concentrate. Thereby, the filter 83 is washed and regenerated, and solid-liquid separation can be performed again.

(Third embodiment) (Device of the third embodiment)

Next, a water treatment apparatus 1B used in the water treatment method of the third embodiment will be described with reference to Fig. 7. In addition, the description of the part which overlaps this embodiment and the above embodiment is abbreviate|omitted.

In the water treatment device 1B of the present embodiment, the raw water is directly sent to the sink from the raw water tank 3 through the line L1 without performing pretreatment with raw water. The separation tank 5 is lowered, and the inorganic particles contained in the raw water are directly divided into a first particle group (first drainage) and a second particle group (second drainage).

This embodiment is a process for separating the floating solid matter (SS) other than the precipitated calcium fluoride particles and the precipitated calcium fluoride particles. In such a process, the raw water tank 3 is directly connected to the classification means (sedimentation separation tank 5) and the raw water is pumped by the pump P1, whereby the inorganic particles can be separated from the water with less energy consumption.

According to the above embodiment, the quality of the treated water can be improved by classifying the inorganic particles in the drainage without using a special chemical.

[Examples]

When described in more detail using the embodiments, it is as described below.

(Preparation of calcium carbonate)

(calcium carbonate particles A)

Calcium carbonate particles A (average particle diameter 15 μm) have been prepared.

(calcium carbonate particles B)

Calcium carbonate particles B (average particle diameter 4 μm) have been prepared.

(calcium carbonate particles C)

Calcium carbonate particles C (average particle diameter 30 μm) have been prepared.

In addition, no matter which kind of particles A, B, and C are used, a ball mill is used to pulverize a commercially available calcium carbonate reagent (manufactured by Wako Pure Chemical Industries, Ltd.), and after removing particles larger than 40 μm, The average particle size is adjusted by wind selection. Here, the average particle diameter is a complex number measured by a laser diffraction method. The measured values are obtained by adding the average. Specifically, the particle diameter of the calcium carbonate particles C was measured using a SALD-DS21 type measuring device (product name) manufactured by Shimadzu Corporation. Further, the average particle diameter of the calcium carbonate particles C is defined as a volume average particle diameter (Mean Volume Diameter).

(Example 1)

The first figure shows a schematic device. An aqueous hydrogen fluoride solution containing 1000 mg/L of fluoride ions was prepared as water to be treated. The water to be treated was placed in the reaction tank 2, and the calcium fluoride particles A were charged in a molar amount of 1 mol to the fluoride ion, and when the mixture was mixed for 10 minutes, the fluoride ion concentration in the water was confirmed to be 8mg / L or less.

Thereafter, the water to be treated is transferred from the reaction tank 2 to the sedimentation separation tank 5 through the pump P1, and when the flow rate is adjusted and settled and separated so that the average residence time becomes 20 minutes, it can be obtained from the lower portion of the sedimentation separation tank 5, respectively. A slurry containing particles having a particle diameter of an average particle diameter of about 20 μm, and a slurry having particles having an average particle diameter of about 4 μm obtained from the upper portion of the sedimentation separation tank 5, and the muds are transferred to the large particle drainage tank 6 respectively. With a small particle drainage channel 7. Next, the pump P2 is started to supply the slurry containing the large particle drainage tank 6 to the horizontal filter 83 of the solid-liquid separation device 8. This filter 83 is a filter cloth of polypropylene. After the pre-coating layer having a thickness of about 1 mm is formed on the filter 83, the slurry is supplied from the small particle-containing drain tank 7 to the solid-liquid separation device 8, and the small particles are separated and recovered. The solid content of the treatment liquid at this time is 10 mg/L or less, and the concentration of the fluoride ion is also 8 mg/L or less.

Thereafter, the treatment liquid is supplied from the washing water supply port provided in the upper portion of the solid-liquid separation device 8 to a flow amount of 5% of the total amount of water, thereby obtaining particles condensed into the reference liquid from the washing water recovery port. A mixture of calcium carbonate and calcium fluoride particles at a concentration of 20 times. Here, the "reference liquid" means the concentration of the inorganic particles in the drainage when the calcium fluoride particles are precipitated.

When the test was repeated using the same filter 83, although the initial pressure loss of the filter 83 before the third test was increased by 0.05 MPa from the initial pressure loss at the first test, in the fourth In the subsequent test, the initial pressure loss of the filter 83 does not rise above this level and does not cause clogging in the filter 83, and the filter 83 and the calcium carbonate particles A can be stably used repeatedly.

(Comparative Example 1)

The same test was carried out except that the sedimentation separation tank 5 of Fig. 1 was not used, and the treated water was directly supplied from the reaction tank 2 to the solid-liquid separation device 8 and directly filtered. The treated water obtained from the solid-liquid separation device 8 passed fine particles in the first 3 minutes and contained particles of an average of 46 mg/L. After that, the filtration was terminated without the passage of finer particles. In the same manner as in the first embodiment, the treatment liquid is supplied from the washing water supply port provided in the upper portion of the solid-liquid separator 8 to the amount of 5% of the total amount of the water to be condensed from the washing water recovery port. A mixture of calcium carbonate and calcium fluoride particles having a particle concentration of 20 times the reference liquid. When the test was repeated using the same filter 83, since the initial pressure loss of the filter 83 was increased by 0.2 MPa before the third test, in the fourth test The same filter 83 cannot be used.

(Example 2)

The same test as in Example 1 was carried out, except that calcium carbonate particles B were used instead of calcium carbonate particles A. The sedimentation separation tank 5 is divided into particles having an average of 11 μm and an average of 2.3 μm, and the same treatment can be performed. The solid content of the treatment liquid at this time is 10 mg/L or less, and the concentration of the fluoride ion is also 8 mg/L or less. When the test was repeated using the same filter 83, although the initial pressure loss of the filter 83 was increased by 0.08 MPa before the third test, the initial pressure loss of the filter 83 in the test after the fourth time was The filter 83 and the calcium carbonate particles B can be continuously used stably without increasing the degree or higher.

(Example 3)

The same test as in Example 1 was carried out, except that calcium carbonate particles C were used instead of calcium carbonate particles A. The sedimentation separation tank 5 is divided into particles having an average of 35 μm and an average of 5 μm, and the same treatment can be performed. The solid content concentration of the treatment liquid at this time is 15 mg/L or less, and the concentration of fluoride ions is 8 mg/L or less. When the test was repeated using the same filter 83, although the initial pressure loss of the filter 83 was increased by 0.04 MPa before the third test, the initial pressure loss of the filter 83 in the test after the fourth time was It does not rise above this level and can stably use the filter 83 and calcium carbonate particles continuously. Sub C.

(Example 4)

The same test as in Example 1 was carried out except that the apparatus 1A shown in Fig. 5 was used. In the liquid cyclone 9, a Toshiba cyclone S-30 was used. After passing through the cyclone, a slurry containing particles having an average particle diameter of 18 μm was obtained from the lower portion of the cyclone, and a slurry containing particles having an average particle diameter of 4 μm was obtained from the upper portion. When the mixture is supplied to the solid-liquid separation device 8 in the same manner as in the first embodiment, the solid content concentration of the treatment liquid at this time is 10 mg/L or less, and the concentration of the fluoride ion is 8 mg/L or less. When the test was repeated using the same filter 83, although the initial pressure loss of the filter 83 was increased by 0.05 MPa before the third test, the initial pressure loss of the filter 83 in the test after the fourth time was The pressure loss above this level is not increased, and the filter 83 and the calcium carbonate particles A can be continuously used stably.

(Example 5)

The simulated drainage is treated using the apparatus 1B shown in FIG. A slurry containing a total of 300 mg/L of magnetite particles having an average particle diameter of 3 μm and manganese-magnesium ferrite particles having an average particle diameter of 35 μm was prepared as a simulated drainage. The simulated drainage water is pumped to the sedimentation separation tank 5, and when the flow rate is adjusted and settled and separated by an average residence time of 20 minutes, it is possible to obtain an average particle diameter of about 35 μm from the lower portion of the sedimentation separation tank 5, respectively. Particle diameter Mud, and a slurry having particles having an average particle diameter of about 3 μm is obtained from the upper portion of the sedimentation separation tank 5, and these muds are transferred to the large particle-containing drainage tank 6 and the small particle-containing drainage tank 7, respectively. Next, the pump P2 is started to supply the slurry containing the large particle drainage tank 6 to the horizontal filter 83 of the solid-liquid separation device 8. This filter uses a filter cloth of polypropylene. After the pre-coating layer having a thickness of about 1 mm is formed on the filter 83, the slurry is supplied from the small particle-containing drain tank 7 to the solid-liquid separation device 8, and small particles are recovered. The solid content of the treatment liquid at this time was 2 mg/L.

(Comparative Example 2)

Except that the slurry containing an average of 2 μm of magnetite having a total of 300 mg/L and an average of 35 μm of manganese-magnesium ferrite was used as the treated water of Example 5, when the rest of the tests were carried out in the same manner as in Example 5, Mud having a particle diameter of an average particle diameter of about 35 μm was obtained from the lower portion of the sedimentation separation tank 5, respectively, and a slurry having particles having an average particle diameter of about 2 μm was obtained from the upper portion of the sedimentation separation tank 5. Thereafter, the slurry containing the large particle drainage tank 6 is circulated to the solid-liquid separation device 8 having the filter 83 horizontal with respect to the ground. This filter uses a filter cloth of polypropylene. After the muddy water is circulated, and a pre-coating layer having a thickness of about 1 mm is formed on the filter 83, the slurry is supplied from the small-particle-containing drain tank 7 to the solid-liquid separation device 8, and small particles are recovered. The solid content concentration of the treatment liquid at this time was 12 mg/L, and it was even worse than that of Example 5.

Claims (12)

A water treatment method characterized in that: (a) one of a sedimentation separation method or a centrifugal separation method is used, and the average particle diameter of the first particle group is larger than the average particle diameter of the second particle group, The inorganic particles contained in the water are classified into the first particle group and the second particle group, whereby the raw water can be divided into a first water containing the first particle group and a second water containing the second particle group. (b) sending the first drainage first to the solid-liquid separation device having the filter, and depositing the inorganic particles of the first particle group on the filter; (c) after the step (b), The second drainage is sent to the solid-liquid separation device, and the inorganic particles of the second particle group are deposited on the filter to form a pre-coating layer of the inorganic particles having the first and second particle groups. (d) peeling the pre-coating layer from the filter, and discharging the exfoliated material from the solid-liquid separating device. The water treatment method according to claim 1, wherein in the step (a), the raw water is divided into the first drainage water and the second drainage water by a sedimentation separation method. The water treatment method according to the first aspect of the invention, wherein in the step (a), the raw water is divided into the first drainage water and the second drainage water by a centrifugal separation method. The water treatment method according to the first aspect of the invention, wherein, in the step (a), the average particle diameter of the inorganic particles of the first particle group and the inorganic particles of the second particle group are The difference Δd is in a range of more than 6% and 50% or less (0.06 d _L < Δd ≦ 0.50 d _L ) of the average particle diameter d _L of the inorganic particles of the first particle group. The water treatment method according to claim 1, wherein the filter of the solid-liquid separation device has a filter surface orthogonal to a direction in which gravity acts. The water treatment method according to claim 1, wherein before the step (a), the method further comprises: a pretreatment step of adding a calcium-containing filter aid to the raw water to cause the calcium-containing filter aid The cation generated by dissolving the agent in water reacts with the anion in the raw water, and precipitates particles of the reaction compound as the inorganic particles. The water treatment method according to claim 6, wherein in the pretreatment step, a fine powder of calcium carbonate is added to the raw water as the calcium-containing filter aid, and the fluoride ion contained in the raw water is The form of calcium fluoride particles precipitates. The water treatment method according to claim 7, wherein the fine powder of calcium carbonate is composed of particles having an average particle diameter of 4 μm to 30 μm. A water treatment device comprising: (A) a classification means for causing inorganic particles contained in raw water to have an average particle diameter of the first particle group larger than an average particle diameter of the second particle group, Dividing into the first particle group and the second particle group, thereby dividing the raw water into the first water containing the first particle group and including the foregoing a second type of drainage of the second drainage of the second particle group; and (B) a solid-liquid separation device having a filter surface that is orthogonal to the direction of gravity, and is partitioned into upper and lower by the filter. And having an upper space and a lower space, wherein the first space and the second drainage water are respectively guided from the classification means to the filter, and the lower space is adapted to pass water through the filter And (C) a drain supply line provided between the classification means and the solid-liquid separation means, wherein the first and second drains are respectively passed; and (D) the first temporary storage tank; Provided in the drainage supply line, and temporarily storing the first drainage from the classification means; and (E) the second temporary storage tank, which is provided in the drainage supply line, and temporarily stores the foregoing from the classification means (2) a drain valve; and (F) a switching valve provided in the drain supply line, and the drain supply line connected to the solid-liquid separator in the first temporary storage tank and the second temporary storage Switch between. The water treatment device according to claim 9, wherein the classification means separates the inorganic particles into the sedimentation separation grooves of the first particle group and the second particle group by the action of gravity. The water treatment device according to claim 9, wherein the classification means is a liquid cyclone that separates the inorganic particles into the first particle group and the second particle group by a centrifugal force. The water treatment device according to claim 9, wherein the water treatment device further comprises: a drainage water containing fluoride ions as the raw water supply Pump and raw water tank to the above classification means.