WO2014083716A1 - Method for treating fluorine-containing wastewater, and apparatus for treating fluorine-containing wastewater - Google Patents

Abstract

A method for treating fluorine-containing wastewater according to an embodiment comprises the steps of: bringing the fluorine-containing wastewater into contact with a calcium agent in a reaction vessel to cause the reaction of fluorine in the fluorine-containing wastewater with the calcium agent, thereby producing calcium fluoride in the fluorine-containing wastewater; and subjecting the calcium fluoride to solid/liquid separation in a solid/liquid separation apparatus placed on the downstream side of the reaction vessel to remove the calcium fluoride from the fluorine-containing wastewater, thereby producing primarily-treated water of the fluorine-containing wastewater and a slurry containing the fluoride calcium. The method additionally comprises the steps of: electrodialyzing the primarily-treated water in an electrodialysis apparatus placed on the downstream side of the solid/liquid separation apparatus to concentrate and remove fluorine ions contained in the primarily-treated water, thereby producing finally-treated water of the fluorine-containing wastewater; and washing the solid/liquid separation apparatus with the primarily-treated water.

Description

Fluorine-containing wastewater treatment method and fluorine-containing wastewater treatment apparatus

Embodiments of the present invention relate to a method for treating fluorine-containing wastewater and a treatment apparatus for fluorine-containing wastewater.

Fluorine emitted from the manufacturing processes of electronic devices and semiconductors that are expanding in the Asian region is effective for the human body up to a predetermined concentration. For example, a concentration of about 1 mg / L is said to have a caries-suppressing effect. Yes. However, since it is known that excessive intake will adversely affect the human body, the Water Pollution Control Law defines drainage standards.

Until now, fluorine in fluorine-containing wastewater has been treated by a treatment method in which it reacts with a calcium agent and is immobilized as calcium fluoride. However, since calcium fluoride dissolves in water in a small amount, there is a problem that the fluorine concentration in the fluorine-containing wastewater cannot be sufficiently reduced by the single treatment with the calcium agent and the drainage standard cannot be cleared.

For example, in Patent Document 1, when a calcium agent is added to fluorine-containing wastewater to separate fluorine into calcium fluoride as a solid-liquid separation, the ionic strength of fluorine-containing wastewater whose water quality varies is measured, and calcium is measured based on the measured value. The amount of additive added is controlled. However, since such a coagulation sedimentation method is a method in which calcium fluoride is generated and fluorine is immobilized as described above, there is a problem that fluorine in the fluorine-containing wastewater cannot be sufficiently reduced. Moreover, in order to reduce the fluorine concentration, a large amount of sludge is generated due to the injection of the polymer flocculant, which increases the environmental load and generates disposal costs.

In Patent Document 2, the concentration of calcium in a calcium solution in which slaked lime and an acid are mixed is measured, and the calcium solution is added based on the calcium concentration to generate calcium fluoride crystals. A method of immobilizing is disclosed. However, since such a crystallization method is a method in which calcium fluoride is generated and fluorine is fixed as described above, there is a problem that fluorine in the fluorine-containing wastewater cannot be sufficiently reduced. Further, there is a problem that the system becomes complicated and the processing cost increases.

JP 2009-233568 A JP 2009-011876 A

An object of the present invention is to provide a method for removing fluorine in a fluorine-containing wastewater at a sufficiently low cost.

In the treatment method of fluorine-containing wastewater of the embodiment, in the reaction tank, the fluorine-containing wastewater and the calcium agent are contacted, and the fluorine in the fluorine-containing wastewater is reacted with the calcium agent, to the fluorine-containing wastewater. In the step of generating calcium fluoride and the solid-liquid separator disposed downstream of the reaction tank, the calcium fluoride is separated from the fluorine-containing wastewater by solid-liquid separation, and the fluorine-containing wastewater 1 Obtaining a slurry containing next treated water and said calcium fluoride. Further, in the electrodialysis apparatus disposed on the downstream side of the solid-liquid separator, the primary treated water is electrodialyzed, and the fluorine ions contained in the primary treated water are concentrated and removed. Obtaining a final treated water of fluorine-containing wastewater, and washing the solid-liquid separation device with the primary treated water.

It is a figure which shows schematic structure of the processing apparatus of the fluorine-containing wastewater in 1st Embodiment. It is a figure which shows schematic structure of the processing apparatus of the fluorine-containing wastewater in 2nd Embodiment. It is a figure which shows schematic structure of the processing apparatus of the fluorine-containing wastewater in 3rd Embodiment. It is an example of the graph which shows the relationship between the electrical conductivity in the final treated water, and a fluorine ion concentration. It is a figure which shows schematic structure of the processing apparatus of the fluorine-containing wastewater in 4th Embodiment. It is a figure which shows schematic structure of the processing apparatus of the fluorine-containing wastewater in 5th Embodiment. It is a figure which shows schematic structure of the processing apparatus of the fluorine-containing wastewater in 6th Embodiment. It is a figure which shows schematic structure of the processing apparatus of the fluorine-containing wastewater in 7th Embodiment. It is a figure which shows schematic structure of the processing apparatus of the fluorine-containing wastewater in 8th Embodiment.

(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of a treatment apparatus for fluorine-containing wastewater in the present embodiment.
The fluorine-containing wastewater treatment apparatus 100 shown in FIG. 1 contacts and reacts a storage tank 11 for storing the fluorine-containing wastewater W0, a fluorine-containing wastewater W0 disposed on the downstream side of the storage tank 11, and a calcium agent. And a temporary storage tank 13 disposed on the downstream side of the reaction tank 12. A solid-liquid separation device 14 and a primary treated water storage tank 15 are disposed on the downstream side of the temporary storage tank 13, and an electrodialysis apparatus 16 is disposed on the downstream side of the solid-liquid separation apparatus 14. In the electrodialysis apparatus 16, a power supply 17 for supplying a direct current is connected to electrodes located at both ends of the electrodialysis apparatus 16.

Further, a calcium agent storage tank 18 for storing the calcium agent is disposed above the reaction tank 12.

In addition, although the solid-liquid separator 14 can be comprised from a general purpose thing, it is preferable to comprise from a horizontal filter so that it may demonstrate below.

The electrodialysis apparatus 16 includes a cation exchange membrane 161 and an anion exchange membrane 162, an anode 162C, and a cathode 161A. The anode 162C and the cathode 161A are connected to a power source 17. Between the anode 162C and the cation exchange membrane 161, the cation exchange membrane 161 and the anion exchange membrane 162, and the anion exchange membrane 162 and the cathode 161A, a desalting chamber 16A, a concentration chamber 16B, and a desalting chamber 16A are sequentially provided. Is defined and formed. That is, the desalination chamber 16 </ b> A is positioned on both sides of the electrodialysis apparatus 16, and the concentration chamber 16 </ b> B is positioned in the center of the electrodialysis apparatus 16.

The storage tank 11 and the reaction tank 12 are connected by a pipe 21, and a pump 31 is disposed in the pipe 21. The reaction tank 12 and the temporary storage tank 13 are connected by a pipe 22, and a pump 32 is provided in the pipe 22. The temporary storage tank 13 and the solid-liquid separator 14 are connected by a pipe 23, and a pump 33 is provided in the pipe 23. The solid-liquid separator 14 and the primary treated water storage tank 15 are connected by a pipe 24.

Further, the desalination chamber 16A and the concentration chamber 16B of the electrodialysis apparatus 16 and the primary treated water storage tank 15 are connected by a pipe 28, and a pump 34 is disposed in the pipe 28. Further, the primary treated water storage tank 15 and the solid-liquid separation device 14 are also connected by a pipe 29 functioning as a cleaning line as will be described below, and a pump 35 is disposed in the pipe 29. .

In the reaction tank 12 and the temporary storage tank 13, a stirrer can be provided as appropriate.

Next, a method for treating the fluorine-containing wastewater W0 using the fluorine-containing wastewater treatment apparatus 100 shown in FIG. 1 will be described.

First, after introducing a predetermined amount of fluorine-containing wastewater W0 into the storage tank 11, the pump 31 is driven to introduce it into the reaction tank 12 through the pipe 21. Next, the calcium agent is charged into the reaction tank 12 from the calcium agent storage tank 18 disposed above the reaction tank 12, and is brought into contact with the fluorine-containing waste water W0 in the reaction tank 12, so that the fluorine in the fluorine-containing waste water W0 It reacts with a calcium agent to produce calcium fluoride. At this time, the fluorine-containing wastewater W0 can be stirred with a stirrer (not shown) to increase the degree of contact between the fluorine and the calcium agent, thereby promoting the reaction.

If the introduction amount of the fluorine-containing wastewater W0 can be controlled by arranging a regulator or the like, the storage tank 11 can be omitted as appropriate, and the fluorine-containing wastewater W0 can be directly introduced into the reaction tank 12. it can.

Examples of calcium agents include calcium carbonate, calcium chloride, calcium hydroxide and the like. Preferably, calcium carbonate having low solubility in water is preferable. Even if an excessive amount of calcium agent is added, it is difficult to elute as ions, so that the electrodialysis load in the subsequent stage can be reduced.

When calcium carbonate is used, the reactivity with fluorine decreases, so it is preferable to add it as a powder having a large specific surface area. For example, a powder having a specific surface area of about 0.1 to 10 m ² / g is preferably used. When calcium chloride is used, the reactivity with fluorine is improved, while the generated calcium fluoride particles are miniaturized. Accordingly, the type of calcium agent to be used is appropriately set in consideration of the separation ability of the solid-liquid separation device 14 located on the downstream side. Further, the amount of calcium agent added can be set low by combining with electrodialysis, and for example, it is desirable to suppress it to about 0.5 to 6.0 times the fluorine equivalent.

Next, the fluorine-containing wastewater W0 containing calcium fluoride is temporarily stored in the temporary storage tank 13 via the pipe 22 by driving the pump 32, and then the pipe 33 is driven by driving the pump 33. Into the solid-liquid separator 14. Although the temporary storage tank 13 can be omitted as appropriate, by providing the primary storage tank 13, the fluorine-containing wastewater W0 is stirred by a stirrer (not shown) disposed in the temporary storage tank 13, and the fluorine, calcium agent, The contact degree can be further increased, and the above reaction can be promoted.

In the solid-liquid separator 14, the fluorine-containing waste water W0 containing calcium fluoride is separated into primary treated water W1 and slurry containing calcium fluoride. The primary treated water W <b> 1 is transferred to the electrodialysis apparatus 16 through the pipe 28 and used for electrodialysis in the electrodialysis apparatus 16.

In addition, when the solid-liquid separation apparatus 14 is comprised from the horizontal filter, the layer of calcium fluoride (solid substance in a figure) is formed on the filter in the said apparatus, and it is still unreacted in the said layer. Therefore, the fluorine in the fluorine-containing wastewater W0 supplied later reacts with the unreacted calcium agent to form calcium fluoride. Therefore, in this case, the solid-liquid separator 14 also functions as a reaction tank that generates calcium fluoride. Such a function remarkably appears when a solid calcium agent having low solubility such as calcium carbonate or calcium hydroxide is used.

In the electrodialysis device 16, electrodialysis is performed by supplying a direct current or a direct voltage through the power source 17, and the fluorine ions in the primary treated water W1 are confined in the concentration chamber 16B. As a result, in the desalting chambers 16A located on both sides of the electrodialyzer 16, the final treated water Wf from which fluorine ions, ie, fluorine have been removed, is generated and stored.

The final treated water Wf is taken out from the electrodialyzer 16 and subjected to a predetermined post-treatment through the pipe 26. Further, the concentrated fluorine water Wc generated in the concentration chamber 16B located in the center of the electrodialyzer 16 is similarly taken out from the electrodialyzer 16 and subjected to a predetermined post-treatment through the pipe 27.

As described above, according to the method for treating fluorine-containing wastewater W0 according to the present embodiment, calcium fluoride is generated by contacting and reacting the fluorine-containing wastewater W0 with calcium, and then 1 containing fluoride ions. Fluorine removal is performed by a two-stage operation in which the primary treated water W1 is charged into the electrodialyzer 16 to perform electrodialysis, and fluorine is removed from the primary treated water W1. Therefore, fluorine in the fluorine-containing wastewater can be removed at a sufficiently low cost.

In the present embodiment, the primary treated water W1 stored in the primary treated water storage tank 15 is driven by the pump 35 and the valve 44 is opened, so that the solid-liquid separation device 14 is connected via the pipe 29. The inside of the solid-liquid separator 14 can be washed. Therefore, clogging of the solid-liquid separator 14 can be prevented, and the function of the solid-liquid separator 14 can always be maintained.

The slurry washed from the solid-liquid separator 14 can be taken out of the processing apparatus 100 via the pipe 25 and a pipe (not shown).

Further, since the desalination chamber 16A and the concentration chamber 16B of the electrodialysis apparatus 16 are connected to the primary treated water storage tank 15 via a pipe 28, the pump 34 is driven and valves 41, 42 and 43 are driven. By opening at least one of these, a part of the final treated water Wf and the concentrated fluorine water Wc present in the desalting chamber 16A and the concentrating chamber 16B of the electrodialyzer 16 is introduced into the primary treated water storage tank 15. You can also. In this case, the concentration of fluorine and excess residue in the primary treated water W1 is reduced and the purity of the primary treated water W1 is improved, so that the cleaning can be performed more effectively.

(Second Embodiment)
FIG. 2 is a diagram showing a schematic configuration of a fluorine-containing wastewater treatment apparatus in the present embodiment. In the fluorine-containing wastewater treatment apparatus 200 of the present embodiment, the concentration chamber 16B of the electrodialysis apparatus 16 is joined to the storage tank 11 via a pipe 51 in the fluorine-containing wastewater treatment apparatus 100 shown in FIG. It is different in point. Therefore, in the processing method of fluorine-containing wastewater of this embodiment, the difference of the processing process based on the difference of such an apparatus is demonstrated.

In addition, the same code | symbol is used about the same or same component as the component of the processing apparatus 100 of a fluorine-containing wastewater shown in FIG.

In the fluorine-containing wastewater treatment method of the present embodiment, as described above, the concentration chamber 16B of the electrodialysis apparatus 16 is joined to the storage tank 11 via the pipe 51. The obtained concentrated fluorine water Wc can be refluxed to the storage tank 11 via the pipe 51.

Therefore, the fluorine-enriched water Wc can be used again for the treatment process described in the first embodiment, and similarly obtained as the final treated water Wf. As a result, fluorine can be sufficiently removed from the fluorine-containing wastewater W1 initially introduced into the treatment apparatus 200 for fluorine-containing wastewater, and the amount of fluorine contained in the final treated water Wf can be sufficiently reduced.

(Third embodiment)
FIG. 3 is a diagram showing a schematic configuration of a treatment apparatus for fluorine-containing wastewater in the present embodiment. Note that the fluorine-containing wastewater treatment apparatus 300 of the present embodiment is the same as the fluorine-containing wastewater treatment apparatus 200 shown in FIG. The difference is that the first conductivity meter 71 is disposed in the final treated water storage tank 61. Therefore, in the processing method of fluorine-containing wastewater of this embodiment, the difference of the processing process based on the difference of such an apparatus is demonstrated.

In addition, the same code | symbol is used about the component similar to or the same component of the processing apparatus 100 of fluorine-containing wastewater shown in FIG. 1 and the processing apparatus 200 of fluorine-containing wastewater shown in FIG.

In the method for treating fluorine-containing wastewater of the present embodiment, as described above, the desalting chamber 16A of the electrodialysis apparatus 16 is joined to the final treated water storage tank 61 via the pipe 26. The final treated water storage tank 61 can be transferred via the pipe 26. The electrical conductivity of the final treated water Wf can be measured by the first conductivity meter 71 disposed in the final treated water storage tank 61.

FIG. 4 is an example of a graph showing the relationship between the electrical conductivity in the final treated water Wf and the fluorine ion concentration. As is clear from FIG. 4, it can be seen that the electrical conductivity in the final treated water Wf and the fluorine ion concentration are in a linear relationship. Therefore, in this embodiment, the concentration of fluorine (ion) in the final treated water Wf can be indirectly known by measuring the electrical conductivity of the final treated water Wf in the final treated water storage tank 61. .

In the present embodiment, a control signal is transmitted from the first conductivity meter 71 to the power source 17, thereby controlling the strength of the DC current or DC voltage applied to the electrodialysis apparatus 16. For example, as a result of measurement of the fluorine concentration in the final treated water Wf by the first conductivity meter 71, if the fluorine concentration is higher than the target fluorine concentration, a direct current or a direct voltage applied to the electrodialysis apparatus 16 The concentration of fluorine (ion) by electrodialysis can be increased to reduce the concentration of fluorine in the final treated water Wf generated in the desalting chamber 16A of the electrodialyzer 16.

On the other hand, when the fluorine concentration is lower than the target fluorine concentration, the degree of concentration of fluorine (ion) by electrodialysis can be reduced by reducing the direct current or the direct voltage applied to the electrodialyzer 16. In this case, since the electric power supplied to the electrodialysis apparatus 16 can be reduced, the treatment cost of the fluorine-containing wastewater W1 can be reduced.

Moreover, since the concentrating chamber 16B of the electrodialysis apparatus 16 is joined to the storage tank 11 via the piping 51 like the fluorine-containing wastewater treatment apparatus 200 in the second embodiment, the concentrating chamber of the electrodialysis apparatus 16 The fluorine-enriched water Wc obtained in 16B can be refluxed to the storage tank 11 through the pipe 51.

Therefore, the fluorine-enriched water Wc can be used again for the treatment process described in the first embodiment, and similarly obtained as the final treated water Wf. As a result, fluorine can be sufficiently removed from the fluorine-containing wastewater W1 initially introduced into the treatment apparatus 300 for fluorine-containing wastewater, and the amount of fluorine contained in the final treated water Wf can be sufficiently reduced.

(Fourth embodiment)
FIG. 5 is a diagram showing a schematic configuration of a treatment apparatus for fluorine-containing wastewater in the present embodiment. Note that the fluorine-containing wastewater treatment apparatus 400 of the present embodiment includes a second conductivity meter 72 in the primary treated water storage tank 15 in the fluorine-containing wastewater treatment apparatus 300 shown in FIG. It is different in point. Therefore, in the processing method of fluorine-containing wastewater of this embodiment, the difference of the processing process based on the difference of such an apparatus is demonstrated.

Regarding the components similar to or the same as those of the fluorine-containing wastewater treatment apparatus 100 shown in FIG. 1, the fluorine-containing wastewater treatment apparatus 200 shown in FIG. 2, and the fluorine-containing wastewater treatment apparatus 300 shown in FIG. The same code is used.

In the method for treating fluorine-containing wastewater according to this embodiment, as described above, the second conductivity meter 72 is disposed in the primary treated water storage tank 15, so the electrical conductivity of the primary treated water W1. By measuring the concentration of fluorine in the primary treated water W1. The fluorine concentration in the primary treated water W1 is easily affected by the fluorine concentration of the fluorine-containing wastewater W0 introduced into the treatment apparatus 400.

On the other hand, as described in the third embodiment, the final treated water Wf is transferred to the final treated water storage tank 61 via the pipe 26, and the first conductivity disposed in the final treated water storage tank 61 is used. By the total 71, the fluorine concentration in the final treated water Wf can be detected.

Therefore, in the present embodiment, a control signal is transmitted from the first conductivity meter 71 to the power source 17, and further, a control signal is transmitted from the second conductivity meter 72 to the power source 17. . As a result, the power source 17 applies a direct current or a direct voltage to the electrodialysis device 16 in consideration of not only the fluorine concentration in the final treated water Wf but also the fluorine concentration in the fluorine-containing wastewater W0 introduced into the treatment device 400. Therefore, the fluorine in the fluorine-containing wastewater W0 can be removed more efficiently.

For this reason, for example, even when the fluorine concentration in the fluorine-containing wastewater W0 introduced into the treatment apparatus 400 greatly fluctuates, the fluctuation can be indirectly detected by the fluorine concentration in the primary treated water W1, By increasing the magnitude of the DC current or DC voltage applied to the electrodialyzer 400 via 17, the above fluctuation can be dealt with.

Moreover, since the concentrating chamber 16B of the electrodialysis apparatus 16 is joined to the storage tank 11 via the piping 51 like the fluorine-containing wastewater treatment apparatus 200 in the second embodiment, the concentrating chamber of the electrodialysis apparatus 16 The fluorine-enriched water Wc obtained in 16B can be refluxed to the storage tank 11 through the pipe 51.

Therefore, the fluorine-enriched water Wc can be used again for the treatment process described in the first embodiment, and similarly obtained as the final treated water Wf. As a result, fluorine can be sufficiently removed from the fluorine-containing wastewater W1 initially introduced into the treatment apparatus 400 for fluorine-containing wastewater, and the amount of fluorine contained in the final treated water Wf can be sufficiently reduced.

(Fifth embodiment)
FIG. 6 is a diagram showing a schematic configuration of a treatment apparatus for fluorine-containing wastewater in the present embodiment. The fluorine-containing wastewater treatment apparatus 500 of this embodiment is the same as the fluorine-containing wastewater treatment apparatus 400 shown in FIG. 5, but the second conductivity meter disposed in the primary treated water storage tank 15. The difference is that the control signal from 72 is also transmitted to the calcium agent reservoir 18.

In the fluorine-containing wastewater treatment method of the present embodiment, a control signal is transmitted from the first conductivity meter 71 to the power source 17, and further, a control signal is transmitted from the second conductivity meter 72 to the power source 17. In addition, a control signal is transmitted to the calcium agent storage tank 18.

As a result, the power source 17 applies a direct current or a direct voltage to the electrodialyzer 16 in consideration of not only the fluorine concentration in the final treated water Wf but also the fluorine concentration in the fluorine-containing wastewater W0 introduced into the treatment apparatus 500. In addition, the amount of calcium agent introduced into the reaction tank 12 can be controlled in consideration of the fluorine concentration in the fluorine-containing wastewater W0. Therefore, the fluorine in the fluorine-containing wastewater W0 can be removed more efficiently.

For this reason, for example, even when the fluorine concentration in the fluorine-containing wastewater W0 introduced into the treatment apparatus 500 greatly fluctuates, the fluctuation can be indirectly detected by the fluorine concentration in the primary treated water W1, At least one of means for increasing the magnitude of a direct current or a direct voltage applied to the electrodialyzer 16 via 17 or increasing the amount of the calcium agent introduced into the reaction tank 12 from the calcium agent storage tank 18. By taking the above, it becomes possible to cope with the above fluctuation.

Since other features are the same as those described in the fourth embodiment, description thereof is omitted.

(Sixth embodiment)
FIG. 7 is a diagram showing a schematic configuration of a treatment apparatus for fluorine-containing wastewater in the present embodiment. The fluorine-containing wastewater treatment apparatus 600 of this embodiment is different from the fluorine-containing wastewater treatment apparatus 500 shown in FIG. 6 in that a third conductivity meter 73 is provided in the storage tank 11. Therefore, in the processing method of fluorine-containing wastewater of this embodiment, the difference of the processing process based on the difference of such an apparatus is demonstrated.

In addition, the fluorine-containing wastewater treatment apparatus 100 shown in FIG. 1, the fluorine-containing wastewater treatment apparatus 200 shown in FIG. 2, the fluorine-containing wastewater treatment apparatus 300 shown in FIG. 3, the fluorine-containing wastewater treatment apparatus 400 shown in FIG. Constituent elements that are similar or identical to the constituent elements of the treatment apparatus 500 for fluorine-containing wastewater shown in FIG.

In the fluorine-containing wastewater treatment method of the present embodiment, a control signal is transmitted from the first conductivity meter 71 to the power source 17, and further, a control signal is transmitted from the second conductivity meter 72 to the power source 17. In addition, a control signal is transmitted to the calcium agent storage tank 18.

Moreover, since the 3rd conductivity meter 73 is arrange | positioned in the storage tank 11, the fluorine concentration of the fluorine-containing wastewater W0 introduce | transduced in the storage tank 11 can be detected, and calcium is based on this fluorine concentration. A control signal is transmitted to the agent storage tank 18.

As a result, the power source 17 applies a direct current or a direct voltage to the electrodialyzer 16 in consideration of not only the fluorine concentration in the final treated water Wf but also the fluorine concentration in the fluorine-containing wastewater W0 introduced into the treatment device 600. In addition, the amount of calcium agent introduced into the reaction tank 12 can be controlled in consideration of the fluorine concentration in the fluorine-containing wastewater W0. Therefore, the fluorine in the fluorine-containing wastewater W0 can be removed more efficiently.

For this reason, for example, even when the fluorine concentration in the fluorine-containing wastewater W0 introduced into the treatment apparatus 600 greatly fluctuates, the fluctuation can be indirectly detected by the fluorine concentration in the storage tank 11 and the primary treated water W1. Since it is possible to increase the magnitude of the DC current or DC voltage applied to the electrodialyzer 16 via the power source 17, or to increase the amount of calcium agent to be introduced into the reaction tank 12 from the calcium agent reservoir 18 By taking at least one of the means, it becomes possible to cope with the above fluctuation.

Since other features are the same as those described in the fourth embodiment, description thereof is omitted.

(Seventh embodiment)
FIG. 8 is a diagram showing a schematic configuration of a treatment apparatus for fluorine-containing wastewater in the present embodiment. The fluorine-containing wastewater treatment apparatus 700 of this embodiment is different from the fluorine-containing wastewater treatment apparatus 600 shown in FIG. 7 in that a reaction aid storage tank 63 is disposed above the reaction tank 12. . Therefore, in the processing method of fluorine-containing wastewater of this embodiment, the difference of the processing process based on the difference of such an apparatus is demonstrated.

Components similar or identical to those of the fluorine-containing wastewater treatment apparatuses 100 to 300 shown in FIGS. 1 to 3 and the fluorine-containing wastewater treatment apparatuses 400 to 600 shown in FIGS. 5 to 7 are designated by the same reference numerals. Used.

In the fluorine-containing wastewater treatment method of the present embodiment, a reaction aid storage tank 63 is disposed above the reaction tank 12, and the formation of calcium fluoride from the reaction aid storage tank 63 is facilitated. A reaction aid such as sulfuric acid is supplied to the tank.

Further, a control signal is transmitted from the first conductivity meter 71 to the power source 17, and further, a control signal is transmitted from the second conductivity meter 72 to the power source 17, and the calcium agent reservoir 18 and the reaction are transmitted. A control signal is also transmitted to the auxiliary agent storage tank 63.

Furthermore, since the 3rd conductivity meter 73 is arrange | positioned in the storage tank 11, the fluorine concentration of the fluorine-containing wastewater W0 introduced into the storage tank 11 can be detected, and calcium is calculated based on this fluorine concentration. Control signals are transmitted to the agent storage tank 18 and the reaction aid storage tank 63.

As a result, the power source 17 applies a direct current or a direct voltage to the electrodialysis apparatus 16 in consideration of not only the fluorine concentration in the final treated water Wf but also the fluorine concentration in the fluorine-containing wastewater W0 introduced into the treatment apparatus 700. In addition, in consideration of the fluorine concentration in the fluorine-containing wastewater W0, it is possible to control the amount of calcium agent introduced into the reaction tank 12 and the amount of reaction aid introduced. Therefore, the fluorine in the fluorine-containing wastewater W0 can be removed more efficiently.

For this reason, for example, even when the fluorine concentration in the fluorine-containing wastewater W0 introduced into the treatment apparatus 700 greatly fluctuates, the variation can be indirectly detected by the fluorine concentration in the storage tank 11 and the primary treated water W1. Since it is possible to increase the magnitude of the direct current or DC voltage applied to the electrodialysis device 16 via the power source 17, or to increase the amount of calcium agent introduced into the reaction tank 12 from the calcium agent storage tank 18, By taking at least one of the means for increasing the amount of the reaction aid introduced into the reaction vessel 12 from the reaction aid storage tank 19, the above fluctuation can be dealt with.

Since other features are the same as those described in the fourth embodiment, description thereof is omitted.

(Eighth embodiment)
FIG. 9 is a diagram showing a schematic configuration of a treatment apparatus for fluorine-containing wastewater in the present embodiment. Components similar to or the same as those of the fluorine-containing wastewater treatment devices 100 to 300 shown in FIGS. 1 to 3 and the fluorine-containing wastewater treatment devices 400 to 700 shown in FIGS. 5 to 8 are designated by the same reference numerals. Used.

The fluorine-containing wastewater treatment apparatus 800 shown in FIG. 9 contacts and reacts the storage tank 11 for storing the fluorine-containing wastewater W0, the fluorine-containing wastewater W0 disposed on the downstream side of the storage tank 11, and the calcium agent. And a temporary storage tank 13 disposed on the downstream side of the reaction tank 12. A solid-liquid separation device 14 and a primary treated water storage tank 15 are disposed on the downstream side of the temporary storage tank 13, and an electrodialysis apparatus 16 is disposed on the downstream side of the solid-liquid separation apparatus 14. In the electrodialysis apparatus 16, a power supply 17 for supplying a direct current is connected to electrodes located at both ends of the electrodialysis apparatus 16.

Further, above the reaction tank 12, a calcium agent storage tank 18 for storing the calcium agent and a reaction assistant storage tank 63 for storing the reaction assistant are disposed.

In addition, although the solid-liquid separator 14 can be comprised from a general purpose thing, it is preferable to comprise from a horizontal filter so that it may demonstrate below.

The storage tank 11 and the reaction tank 12 are connected by a pipe 21, and a pump 31 is disposed in the pipe 21. The reaction tank 12 and the temporary storage tank 13 are connected by a pipe 22, and a pump 32 is provided in the pipe 22. The temporary storage tank 13 and the solid-liquid separator 14 are connected by a pipe 23, and a pump 33 is provided in the pipe 23. The solid-liquid separator 14 and the primary treated water storage tank 15 are connected by pipes 24 and 25, and the solid-liquid separator 14 and the electrodialyzer 16 are connected by pipes 25 or 29 and 28.

Further, in the treatment apparatus 800 of the present embodiment, a secondary treated water storage tank 68 is disposed in addition to the primary treated water storage tank 15, and is joined to the solid-liquid separator 14 and the pipe 25.

Furthermore, in the processing apparatus 800 of this embodiment, the relay tank 64, the additional reaction tank 65, and the additional temporary storage tank 66 are arrange | positioned. Further, an additional calcium agent storage tank 67 is disposed on the additional reaction tank 65.

The primary treated water storage tank 15 and the relay tank 64 are connected via a pipe 81, and a pump 91 is disposed in the pipe 81. The relay tank 64 and the additional reaction tank 65 are connected via a pipe 82, and a pump 92 is provided in the pipe 82. The additional reaction tank 65 and the additional temporary storage tank 66 are connected via a pipe 83, and a pump 93 is provided in the pipe 83. The additional temporary storage tank 66 and the solid-liquid separator 14 are connected via a pipe 84, and a pump 94 is disposed in the pipe 84.

In the processing apparatus 800 of this embodiment, a cleaning liquid processing system for cleaning the inside of the solid-liquid separation apparatus 14 is disposed on the introduction side of the fluorine-containing waste water W0 of the solid-liquid separation apparatus 14. This cleaning liquid treatment system squeezes the sludge separated from the solid-liquid separator 14 and dehydrates it to perform solid-liquid separation, and a slurry separated from the solid-liquid separator 75. It has a slurry storage tank 76 for holding and storing, and a water tank 69 for storing water generated during pressing. In addition, in the water tank 69, the waste water of the wash water supplied via the piping 88 is also stored in order to isolate | separate a slurry from the solid-liquid separator 75 with a pressing function.

Next, a method for treating the fluorine-containing wastewater W0 using the fluorine-containing wastewater treatment apparatus 800 shown in FIG. 9 will be described.

First, after introducing a predetermined amount of fluorine-containing wastewater W0 into the storage tank 11, the pump 31 is driven to introduce it into the reaction tank 12 through the pipe 21. Next, the calcium agent is charged into the reaction tank 12 from the calcium agent storage tank 18 disposed above the reaction tank 12, and the reaction assistant is further charged into the reaction tank 12 from the reaction assistant storage tank 63. In the reaction tank 12, it is made to contact with the fluorine-containing wastewater W0, and the fluorine in the fluorine-containing wastewater W0 is reacted with the calcium agent to generate calcium fluoride. At this time, the fluorine-containing wastewater W0 can be stirred with a stirrer (not shown) to increase the degree of contact between the fluorine and the calcium agent, thereby promoting the reaction.

If the introduction amount of the fluorine-containing wastewater W0 can be controlled by arranging a regulator or the like, the storage tank 11 can be omitted as appropriate, and the fluorine-containing wastewater W0 can be directly introduced into the reaction tank 12. it can.

Next, the fluorine-containing wastewater W0 containing calcium fluoride is temporarily stored in the temporary storage tank 13 via the pipe 22 by driving the pump 32, and then the pipe 33 is driven by driving the pump 33. Into the solid-liquid separator 14. Although the temporary storage tank 13 can be omitted as appropriate, by providing the primary storage tank 13, the fluorine-containing wastewater W0 is stirred by a stirrer (not shown) disposed in the temporary storage tank 13, and the fluorine, calcium agent, The contact degree can be further increased, and the above reaction can be promoted.

In the solid-liquid separator 14, the fluorine-containing waste water W0 containing calcium fluoride is separated into primary treated water W1 and slurry containing calcium fluoride. The primary treated water W1 is transferred to the electrodialysis apparatus 16 via the pipe 25 or 29 and 28, and used for electrodialysis in the electrodialysis apparatus 16.

In addition, when the solid-liquid separator 14 is comprised from a horizontal filter, the layer (solid substance in a figure) of the calcium fluoride containing an unreacted calcium agent is formed on the filter in the said apparatus.

On the other hand, the primary treated water W1 separated by the solid-liquid separator 14 is stored in the primary treated water storage tank 15 through the pipes 25 and 24. The primary treated water W1 is transferred to the relay tank 64 via the pipe 81 by driving the pump 91, and further transferred to the additional reaction tank 65 by driving the pump 92. In the additional reaction tank 65, the additional calcium agent is added from the additional calcium agent storage tank 67, and the remaining fluorine in the primary treated water W1 reacts with the calcium agent to generate calcium fluoride. .

Next, the primary treated water W1 containing calcium fluoride is transferred to the solid-liquid separator 14 via the pipe 84 by driving the pump 94. At this time, the primary treated water W1 containing calcium fluoride is solid-liquid separated by the solid-liquid separator 14 and separated into the secondary treated water W2 and slurry containing calcium fluoride. The secondary treated water W2 is transferred to the electrodialyzer 16 via the pipe 25 or 29 and 28 ( valves 41 and 42 opened), and used for electrodialysis in the electrodialyzer 16.

In addition, when the solid-liquid separation apparatus 14 is comprised from the horizontal filter, since the layer of the calcium fluoride containing the unreacted calcium agent is formed in the said apparatus, it remains in the primary treated water W1. Fluorine reacts with the residual calcium agent to produce calcium fluoride. Therefore, in this case, the solid-liquid separator 14 also functions as a reaction tank.

In the electrodialysis apparatus 16, as described in the first embodiment, in the desalting chambers 16A located on both sides of the electrodialysis apparatus 16, fluorine ion, that is, final treated water Wf from which fluorine has been removed is generated and stored. Will come to be. The final treated water Wf is taken out from the electrodialyzer 16 and supplied to a predetermined post-treatment through the pipe 26. Further, the concentrated fluorine water Wc generated in the concentration chamber 16B located in the center of the electrodialyzer 16 is similarly taken out from the electrodialyzer 16 and subjected to a predetermined post-treatment through the pipe 27.

As described above, according to the method for treating the fluorine-containing wastewater W0 of the present embodiment, after the calcium agent is brought into contact with and reacted with the fluorine-containing wastewater W0 to generate calcium fluoride, a solid-liquid separation device is further provided. In the same manner as the fluorine-containing waste water W0, the calcium treatment is produced by contacting and reacting the primary treated water W1 obtained in 14 with the calcium-containing waste water W0, and then electrodialyzing the secondary treated water W2 containing the fluorine ions. Fluorine removal is performed by a three-stage operation in which the apparatus 16 is charged with electrodialysis and fluorine is removed from the secondary treated water W2.

Accordingly, since the final treated water Wf is substantially subjected to fluorine removal through three stages of operation, the fluorine concentration in the final treated water Wf obtained in the present embodiment is obtained in the first embodiment or the like. Further, it is sufficiently reduced as compared with the fluorine concentration in the final treated water Wf.

In the present embodiment, the secondary treated water W2 stored in the secondary treated water storage tank 68 is returned to the solid-liquid separation device 14 via the pipe 29 by driving the pump 34, and the solid-liquid separation is performed. The inside of the device 14 can be cleaned. Therefore, clogging of the solid-liquid separator 14 can be prevented, and the function of the solid-liquid separator 14 can always be maintained.

The sludge washed from the solid-liquid separation device 14 is supplied to the solid-liquid separation device 75 with a compression function via the pipe 85, supplied with compressed air CA, dried and compressed and dehydrated. Moisture generated at this time is stored in the water tank 69 via the pipe 86. On the other hand, the solid content remaining in the solid-liquid separation device 75 with a squeezing function is washed by supplying the secondary treated water W <b> 2 via the pipe 88 and stored in the slurry storage tank 76 as a slurry. In addition, the cleaning wastewater generated at this time is similarly stored in the water tank 69 through the pipe 87.

In this embodiment, the washing waste water or the like stored in the water tank 69 is returned to the reaction tank 11 by driving the pump 95. Therefore, since the cleaning wastewater is again subjected to the above operation, the fluorine can be sufficiently removed from the fluorine-containing wastewater W0 initially introduced into the fluorine-containing wastewater treatment apparatus 800, and is contained in the final treated water Wf. The amount of fluorine to be produced can be sufficiently reduced.

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

100, 200, 300, 400, 500, 600, 700, 800 Fluorine-containing wastewater treatment apparatus; 11 storage tank; 12 reaction tank; 13 temporary storage tank; 14 solid-liquid separation apparatus; 15 primary treated water storage tank; Electrodialyzer; 17 Power supply; W0 Fluorine-containing wastewater; W1 Primary treated water; Wf Final treated water; Wc Fluorine concentrated water; 61 Final treated water storage tank; 71 First conductivity meter; 72 Second conductivity meter 73 73 3rd conductivity meter.

Claims (14)

1. In a reaction tank, contacting fluorine-containing wastewater with a calcium agent, reacting fluorine in the fluorine-containing wastewater with the calcium agent, and generating calcium fluoride in the fluorine-containing wastewater;
   In the solid-liquid separation device disposed on the downstream side of the reaction tank, the calcium fluoride is removed from the fluorine-containing wastewater by solid-liquid separation to obtain primary treated water of the fluorine-containing wastewater;
   In the electrodialysis apparatus disposed on the downstream side of the solid-liquid separator, the primary treated water is electrodialyzed and the fluorine ions contained in the primary treated water are concentrated and removed as a fluorine ion-containing concentrate. A step of obtaining a final treated water of the fluorine-containing wastewater,
   And a step of washing the solid-liquid separation device with the primary treated water.
2. The method for treating fluorine-containing wastewater according to claim 1, further comprising a step of refluxing the fluorine ion-containing concentrated liquid into the reaction vessel.
3. Measuring the electrical conductivity of the final treated water with a first conductivity meter, and detecting the concentration of residual fluorine in the final treated water;
   Depending on the concentration of the residual fluorine in the final treated water, controlling the degree of concentration of the fluorine ions in the electrodialyzer;
   The processing method of the fluorine-containing wastewater of Claim 1 or 2 characterized by the above-mentioned.
4. Measuring the electrical conductivity of the primary treated water with a second conductivity meter and detecting the concentration of residual fluorine in the primary treated water;
   Controlling the degree of concentration of the fluorine ions in the electrodialysis device depending on the concentration of the residual fluorine in the primary treated water;
   The processing method of the fluorine-containing wastewater of Claim 3 characterized by the above-mentioned.
5. The fluorine-containing wastewater according to claim 4, further comprising a step of controlling an amount of the calcium agent charged into the reaction tank depending on a concentration of the residual fluorine in the primary treated water. Processing method.
6. Measuring the electrical conductivity in the fluorine-containing waste liquid before being charged into the reaction vessel by a third conductivity meter, and detecting the fluorine concentration in the fluorine-containing waste liquid;
   Depending on the fluorine concentration in the fluorine-containing waste liquid, controlling the amount of the calcium agent charged into the reaction vessel;
   The processing method of the fluorine-containing wastewater of Claim 5 characterized by the above-mentioned.
7. The amount of the reaction aid to be introduced into the reaction tank is controlled by the third conductivity meter depending on the fluorine concentration in the fluorine-containing waste liquid. Treatment method for fluorine-containing wastewater.
8. Instead of washing the solid-liquid separator with the primary treated water,
   Refluxing the primary treated water to the solid-liquid separator;
   In the solid-liquid separator, obtaining the slurry containing the secondary treated water of the fluorine-containing wastewater and the calcium fluoride from the primary treated water;
   In the electrodialysis apparatus disposed on the downstream side of the solid-liquid separator, the secondary treated water is electrodialyzed, and the fluorine ions contained in the secondary treated water are concentrated and removed, whereby the fluorine containing Obtaining a final treated water of waste water;
   Washing the solid-liquid separator with the secondary treated water;
   The processing method of the fluorine-containing wastewater of Claim 7 characterized by the above-mentioned.
9. The method for treating fluorine-containing wastewater according to claim 1, wherein the solid-liquid separator is a horizontal filter.
10. A reaction tank for contacting fluorine-containing wastewater with a calcium agent, reacting fluorine in the fluorine-containing wastewater with the calcium agent, and generating calcium fluoride in the fluorine-containing wastewater;
    For disposing the calcium fluoride from the fluorine-containing wastewater by solid-liquid separation and removing it from the fluorine-containing wastewater to obtain a slurry containing primary treated water of the fluorine-containing wastewater and the calcium fluoride. A solid-liquid separator,
    Disposed downstream of the solid-liquid separator, the primary treated water is electrodialyzed, and the final treated water of the fluorine-containing wastewater is removed by concentrating and removing the fluorine ions contained in the primary treated water. An electrodialyzer for obtaining
    An apparatus for treating fluorine-containing wastewater, comprising:
11. The fluorine-containing wastewater according to claim 10, further comprising a first conductivity meter for measuring electrical conductivity of the final treated water and detecting a concentration of residual fluorine in the final treated water. Processing equipment.
12. The electrical conductivity of the primary treated water is measured, the concentration of residual fluorine in the primary treated water is detected, and the fluorine ion in the electrodialyzer depends on the concentration of the residual fluorine in the primary treated water The apparatus for treating fluorine-containing wastewater according to claim 10, further comprising a second conductivity meter for controlling the degree of concentration of the fluorine-containing wastewater.
13. The electrical conductivity in the fluorine-containing waste liquid before being charged into the reaction vessel is measured, the fluorine concentration in the fluorine-containing waste liquid is detected, and depending on the fluorine concentration in the fluorine-containing waste liquid, the reaction The apparatus for treating fluorine-containing wastewater according to claim 11, further comprising a third conductivity meter for controlling the amount of the calcium agent charged into the tank.
14. The apparatus for treating fluorine-containing wastewater according to claim 10, wherein the solid-liquid separator is a horizontal filter.

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