JP4586582B2 - Dephosphorization device - Google Patents

Description

  The present invention relates to a dephosphorization apparatus.

  The water to be treated is blown into one of the dephosphorization devices for removing phosphate ions contained in the water to be treated by blowing air in the presence of magnesium ions and ammonium ions to the water to be treated supplied from the lower part of the device. There is a device for precipitating a phosphoric acid compound and dephosphorizing it, and discharging this supernatant liquid as treated water (see, for example, Patent Documents 1 to 5).

In such a dephosphorization apparatus, the water to be treated is supplied into the reaction vessel from the lower part of the reaction vessel, and the water to be treated is stirred by air in the reaction vessel to promote the precipitation of the phosphate compound. Then, the precipitated phosphate compound is settled to the lower part of the reaction vessel by its own weight, the phosphate compound is extracted from the lower part of the reaction vessel, and the supernatant in the reaction vessel from which the phosphate ions have been removed is treated from the upper part of the reaction vessel. It is discharged as water.
Japanese Patent Laid-Open No. 8-252584 JP-A-9-206760 JP-A-11-309464 JP-A-8-24875 Japanese Patent Laid-Open No. 10-263769

However, in the conventional dephosphorization apparatus, the water to be treated in the reaction vessel is not sufficiently stirred by air, and the reaction between magnesium ions and phosphate ions in the reaction vessel does not proceed and is contained in the water to be treated. There is a problem that the removal efficiency of phosphate ions is not improved. Thus, when the removal efficiency of the phosphate ion contained in to-be-processed water is not improved, the problem that phosphate ion will be discharged | emitted in the state which remained in treated water arises.
Further, in the conventional dephosphorization apparatus, since air is blown into the reaction apparatus, a large upward flow is generated in the water to be treated in the reaction container along with the air flow, and the phosphoric acid precipitated in the reaction container In some cases, the compound reached the supernatant. Thus, when a phosphoric acid compound reaches to a supernatant liquid, the problem that treated water will be discharged | emitted in the state in which the phosphoric acid compound was contained in treated water will arise.

The present invention has been made in view of the above-described problems, and has the following objects.
(1) The removal efficiency of phosphate ions contained in the water to be treated is improved.
(2) Suppresses the mixing of the phosphate compound into the treated water.

  In order to achieve the above object, in the present invention, as a first means, by blowing air in the presence of magnesium ions and ammonium ions into the water to be treated which contains phosphate ions and is supplied from the lower part of the apparatus, A dephosphorization device for precipitating a phosphate compound from the water to be treated and dephosphorizing it, and discharging the supernatant liquid as treated water from the upper part of the apparatus, which is disposed at the bottom of the apparatus and contains the phosphate compound inside. A granulation vessel for granulation, and a reaction that is arranged on the granulation vessel in communication with the granulation vessel and precipitates the phosphate compound by blowing the air into the water to be treated inside. A container, a recovery container disposed on the reaction container in communication with the reaction container, and collecting the air from the water to be treated inside; A construction is adopted and a stirring means for stirring the Oite the treated water and the air.

  As a second means, in the first means, the stirring means is a cylindrical tube whose end is spaced apart from the granulation container and the recovery container by a predetermined distance and coaxially arranged with the reaction container. The configuration is adopted.

  As a third means, a configuration is adopted in which the second means includes an air supply means that is disposed below the cylindrical tube and blows the air toward the inside of the cylindrical tube.

  As a fourth means, in the second or third means, the granulation vessel and the reaction vessel are arranged coaxially, and the vessel diameter of the reaction vessel is larger than the vessel diameter of the granulation vessel. The configuration that is said to be adopted.

  As a fifth means, in any one of the first to fourth means, the water to be treated collected together with the air and the air are separated, and the water to be treated after separation is separated from the granulation container and the reaction. A configuration in which separation / circulation means for supplying the container is provided is adopted.

  As a sixth means, in the fifth means, the separation / circulation means raises and collects the air collected in the collection container together with a part of the water to be treated, and together with the air A gas-liquid separator that separates the recovered water to be treated and the air; and a downer pipe that supplies the treated water after separation to the granulation vessel and the reaction vessel. A configuration is adopted in which the height on the surface of the water to be treated is set so that the air does not leak from the recovery container.

  As a seventh means, in any one of the first to sixth means, the collection container is disposed on the collection unit for collecting the air from the water to be treated, and is disposed on the collection unit and by the collection unit. A storage section for storing the treated water from which the air has been recovered, and at least a cross-sectional area of the recovery section of the recovery containers is set wider than a cross-sectional area of the reaction container Is adopted.

  As an eighth means, in any one of the first to seventh means, a configuration is adopted in which a cross section of the collection container is set in a rectangular shape.

  According to the present invention, since the reaction vessel is provided with the agitation means for agitating the water to be treated and air, the reaction between magnesium ions and phosphate ions in the reaction vessel is promoted, and phosphorus contained in the water to be treated is contained. It becomes possible to improve the removal efficiency of acid ions.

  Hereinafter, an embodiment of a dephosphorization apparatus according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to facilitate recognition of each member.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a dephosphorization apparatus 1 according to the present embodiment. As shown in this figure, the dephosphorization apparatus 1 according to the present embodiment includes a granulation container 2, a reaction container 3, and a recovery container 4.

The granulation container 2 is a container set in a cylindrical shape, and is disposed as the bottom of the dephosphorization apparatus 1. Then, in the interior of the granulating vessel 2, granulation of the phosphoric acid ion _(HPO ^{4 2-)} phosphoric acid compounds precipitated from the water to be treated X containing (MgNH ₄ PO ₄₎ is performed. The granulation container 2 is connected to an extraction line 27 for extracting the phosphate compound granulated in the granulation container 2.

The reaction vessel 3 is arranged on the granulation vessel 2 in communication with the granulation vessel 2. Similarly to the granulation vessel 2, the reaction vessel 3 is a vessel set in a cylindrical shape, and the vessel diameter of the reaction vessel 3 is larger than the vessel diameter of the granulation vessel 2. The granulation container 2 is arranged coaxially. And in this reaction container 3, the phosphoric acid compound is precipitated from the to-be-processed water X by blowing the air Y with respect to the to-be-processed water X, and the dephosphorization process of the to-be-processed water X is performed.
Inside the reaction vessel 3, a stirring assist pipe 5 (stirring means) for stirring the water to be treated X and the air Y in the reaction vessel 3 is disposed. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1. As shown in this figure, the stirring assisting tube 5 is disposed coaxially with the reaction vessel 3 and is about half the diameter of the reaction vessel 3. The cylindrical tube has a diameter. Further, the lower end 5a of the stirring assisting tube 5 is separated from the granulation container 2 by 80 to 100 cm, and the upper end 5b is separated from the collection container 4 described later by 80 to 100 cm. That is, the reaction vessel 3 has a double tube structure of the reaction vessel main body and the stirring assisting tube 5. In addition, the stirring assistance pipe | tube 5 is supported by connecting with the reaction container main body by the support part not shown.
Further, as shown in FIGS. 1 and 2, a plurality of air diffusers 6 that are arranged vertically below the stirring assisting tube 5 and blow air Y toward the inside of the stirring assisting tube 5 inside the reaction vessel 3. (Air supply means) is arranged, and the air Y is blown into the reaction vessel 3 by supplying the air Y to the air diffuser 6 through the air injection line 21. In addition, it is preferable that the ejection angle of the air Y of the air diffuser 6 is set so that almost all of the air Y ejected from the air diffuser 6 is blown into the stirring assist pipe 5.

  Moreover, the to-be-processed water supply line 22 is connected to the lower part of the granulation container 2 and the reaction container 3, and each inside is processed via the to-be-processed water supply line 22 connected to the lower part of this dephosphorization apparatus 1. To-be-processed water X is supplied. These treated water supply lines 22 are connected to the granulation vessel 2 and the reaction vessel 3 from the tangential direction in plan view. The reaction vessel 3 is connected to a sodium hydroxide supply line 23 for supplying sodium hydroxide into the reaction vessel 3. By supplying sodium hydroxide into the reaction vessel 3 through the sodium hydroxide supply line 23, the pH (7.7) suitable for the water to be treated X in the reaction vessel 3 to precipitate the phosphate compound. To 9.5, preferably 8.1).

  The recovery container 4 is arranged on the reaction container 3 so as to be connected to the reaction container 3, and the cross section is set to a substantially square shape (rectangular shape) and is wider than the cross section (cross sectional area) of the reaction container 3. Container. The recovery container 4 is disposed on the recovery unit 41 for recovering the air Y supplied to the water to be treated X in the reaction container 3, and the air Y is recovered by the recovery unit 41. The storage part 42 which stores the to-be-processed water X was comprised.

  FIG. 3 is a perspective view of the collection unit 41. As shown in this figure, the collection unit 41 includes an air collection unit 43 and a gas hood 44. The gas hood 44 is disposed from the air collecting part 43 to the inner wall surface of the collection container 4. In the present embodiment, the gas hood 44 is disposed in a plurality of stages and in four stages in the horizontal direction. The air collecting part 43 is a box having a hollow inside, and an opening 45 corresponding to each gas hood 44 is formed. And the air Y supplied with respect to the to-be-processed water X is collected by the gas hood 44 of the collection | recovery part 41 comprised in this way, The collected air Y is with a part of to-be-processed water X. The air is collected in the air collecting unit 43 through the opening 45. Here, in the dephosphorization apparatus 1 which concerns on this embodiment, the cross-sectional shape of the collection container 4 is made into substantially square. For this reason, it is possible to secure a sufficient area for collecting the air Y, to make the lengths of all the gas hoods 44 the same, and to collect the air Y uniformly in the entire plan view of the collection container 4. be able to. For this reason, it is possible to prevent the air Y from leaking from the collection unit 41, and it is possible to prevent the air Y from leaking to the storage unit 42.

As shown in FIG. 4, the lower end 44 a of the gas hood 44 preferably extends below the lower end 45 a of the opening 45. Thus, the air Y collected by the gas hood 44 can be prevented from leaking from the end of the gas hood 44 before entering the opening 45, and the air collection efficiency of the recovery unit 41 can be improved. .
The distance D from the left end 44b to the right end 44c of the gas hood 44 is preferably about 1.7 to 1.8 times the lateral width d of the opening 45. As a result, the air collection area and the air collection capacity of each gas hood 44 can be sufficiently secured, and the air collection efficiency of the collection unit 41 can be further improved.

  Returning to FIG. 1, a riser pipe 7 is connected to the upper portion of the air collecting section 43, and this riser pipe 7 is connected to a gas-liquid separator 8 disposed above the collection container 4. As will be described in detail later, the height of the upper portion 71 of the riser pipe 7 from the collection container 4, that is, the height of the upper portion 71 from the water surface of the treated water X is set to a height at which the air Y does not leak from the gas hood 44. Has been. The gas-liquid separator 8 of the riser pipe 7 separates the air Y and the water to be treated X supplied through the riser pipe 7, exhausts the air Y through the ventilation line 24, The liquid is supplied to a downer tube 9 connected to the liquid separator 8. The downer pipe 9 is branched into two pipes 91 and 92 at an intermediate position, the pipe 91 is connected to the reaction vessel 3, and the tube 92 is connected to the granulation vessel 2. The pipe 91 is obliquely connected to the reaction vessel 3 so as to supply the treated water X into the reaction vessel 3 from above to below, and is connected above the lower end 5 a of the stirring assisting tube 5. Yes. As shown in FIG. 2, the tube 91 is connected to the reaction vessel 3 from the tangential direction in plan view. Further, a pump 10 for adjusting the flow rate of the water to be treated X flowing into the pipe 92 and a flow meter 11 for measuring the flow rate of the pipe 92 are installed in the middle of the pipe 92.

Further, in order to supply magnesium (Mg) and ammonium (NH ₄ ) to the pH meter 12 for measuring the pH of the water to be treated X and the water to be treated X in the middle part of the downer pipe 9 before branching. Are connected to the magnesium / ammonium supply line 25. Based on the measurement result of the pH meter 12, sodium hydroxide is appropriately supplied into the reaction vessel 3 from the sodium hydroxide supply line 23 described above.
In addition, a treated water discharge line 26 is connected to the upper part of the reservoir 42 for discharging the supernatant Z collected in the reservoir 42 as treated water to the outside of the dephosphorization apparatus 1.

In the present embodiment, the separation / circulation means in the present invention includes the riser pipe 7, the gas-liquid separator 8, the downer pipe 9, the pipes 91 and 92, and the pump 10.
Moreover, the pump 10 and the flow meter 11 of the dephosphorization device 1 according to the present embodiment are connected to a control device (not shown), and the control device drives the pump 10 based on the measurement result of the flow meter 11. .

  Next, operation | movement of the dephosphorization apparatus 1 which concerns on this embodiment comprised as mentioned above is demonstrated.

First, the water to be treated X supplied to the lower part of the granulation vessel 2 and the reaction vessel 3 via the water to be treated supply line 22 is reacted inside the reaction vessel 3 via the air injection line 21 and the air diffuser 6. 3 is mixed with the air Y blown into the interior 3 and rises in the dephosphorization apparatus 1. Of the to-be-treated water X rising in the reaction vessel 3, the to-be-treated water X that has flowed into the stirring assistance pipe 5 is discharged from the upper end 5b of the stirring assistance pipe 5 and the rising flow N1 and the stirring assistance. A flow N2 that circulates outside the tube 5 and flows downward between the stirring assisting tube 5 and the main body of the reaction vessel 3 is divided. Therefore, a vertical swirl flow S as shown in FIG. 1 is formed in the reaction vessel 3, and the water to be treated X and the air Y are agitated. As will be described later, the water to be treated X supplied with magnesium ions and ammonium ions is supplied into the reaction vessel 3 through the pipe 91, so that the phosphate compound is contained in the water to be treated X in the reaction vessel 3. It is deposited.
And in the dephosphorization apparatus 1 which concerns on this embodiment, since the to-be-processed water X and the air Y in the reaction container 3 are stirred by the stirring assistance pipe 5, precipitation of a phosphoric acid compound is accelerated | stimulated, and to-be-processed water The removal efficiency of phosphate ions contained in X can be improved. In the reaction vessel 3, a phosphoric acid compound having a particle size of about 60 μm is deposited.

Here, in the dephosphorization apparatus 1 according to the present embodiment, the air diffuser 6 is disposed vertically below the stirring assist pipe 5 and is disposed so as to blow air toward the inside of the stirring assist pipe 5. For this reason, the air Y supplied from the air diffuser 6 enters the inside of the stirring assist pipe 5 and promotes the rise of the treated water X inside the stirring assist pipe 5. Further, since almost all of the air Y ejected from the air diffuser 6 is set to be blown into the stirring assisting pipe 5, almost all the air Y ejected from the air diffuser 6 is stirred. The air Y does not interfere with the flow N2 that flows downward between the stirring assist pipe 5 and the main body of the reaction vessel 5. Therefore, the swirl flow S having a strong flow can be formed, and the precipitation of the phosphoric acid compound can be further promoted.
Further, in the dephosphorization apparatus 1 according to the present embodiment, the container diameter of the reaction container 3 is larger than the container diameter of the granulation container 2, and the reaction container 3 and the granulation container 2 are coaxially arranged. Has been placed. For this reason, the to-be-processed water X rising toward the reaction vessel 3 from the granulation vessel 2 rises mainly in the central portion of the reaction vessel 3. Accordingly, it is possible to prevent the flow N2 flowing downward between the stirring assist pipe 5 and the main body of the reaction vessel 5 from being obstructed.

  Subsequently, the to-be-treated water X discharged from the upper end 5 b of the stirring assist pipe 5 rises to the collection unit 41 of the collection container 4 while being mixed with the air Y. And the to-be-processed water X which rose to the collection | recovery part 41 collects the air Y by the collection | recovery part 41. In addition, the phosphoric acid compound contained in the to-be-processed water X hits the gas hood 44 of the collection | recovery part 41, and settles with dead weight. And the to-be-processed water X from which the air Y was collect | recovered and from which the phosphate ion was removed overflows from the upper part of the storage part 42 as the supernatant liquid Z, and the dephosphorization apparatus 1 as treated water through the treated water discharge line 26 Is discharged outside.

Here, in the dephosphorization apparatus 1 according to the present embodiment, the cross-sectional area of the recovery container 4 is made wider than the cross-sectional area of the reaction container 3 as described above. For this reason, the rising flow rate of the supernatant liquid Z is slower than the rising flow rate of the water to be treated X in the reaction vessel 3. Therefore, even if the phosphate compound passes through the collection unit 41, it is possible to prevent the phosphate compound from reaching the upper part of the storage unit 42.
In addition, since the cross-sectional area of the recovery container 4 is larger than the cross-sectional area of the reaction container 3 and the cross-section of the recovery container 4 is rectangular, the air Y leaks from the recovery unit 41 as described above. Can be deterred. For this reason, it is possible to suppress an increase in the ascending flow rate of the supernatant liquid Z due to the air Y leaked from the recovery unit 41, and it is also possible to suppress the phosphate compound from reaching the upper part of the storage unit 42.
Therefore, according to the dephosphorization apparatus 1 which concerns on this embodiment, since it can suppress that a phosphate compound reaches | attains to the upper part of the storage part 42, it suppresses that a phosphate compound mixes in process water. Is possible.

  Moreover, the phosphoric acid compound which precipitates by its own weight finally settles into the granulation vessel 2 and is granulated to a particle size of about 1 to 2 mm in the granulation vessel.

Subsequently, the air Y that has reached the recovery unit 41 in a state of being mixed with the water to be treated X is collected by the recovery unit 41 together with a part of the water to be treated X, and then the gas-liquid separator via the riser pipe 7. 8 is supplied. Here, the air Y rises with the to-be-treated water X in the riser pipe 7 without requiring a driving force such as a pump. This is because the air Y accumulates in the gas hood 44 of the recovery unit 41, thereby increasing the pressure in the gas hood 44, and as a result, the air Y rises in the riser pipe 7 together with the treated water X. Therefore, as the length of the riser pipe 7 becomes longer, the pressure loss in the riser pipe 7 becomes higher, and a higher pressure is required for the air Y to rise in the riser pipe 7. For example, when the pressure loss in the riser pipe 7 is particularly high, even if the air Y is fully accumulated in the gas hood 44, sufficient pressure cannot be obtained so that the air Y can rise. Air Y leaks out. Thus, when the air Y leaks from the gas hood 44, the rising flow rate of the supernatant liquid Z by the air Y increases as described above, and there is a possibility that the phosphate compound reaches the upper part of the reservoir 42. Therefore, it is not preferable.
For this reason, in order to suppress the leakage of the air Y from the gas hood 44 due to the pressure loss in the riser pipe 7, it is preferable to shorten the length of the riser pipe 7. The pressure loss in the riser pipe 7 is particularly high in the upper portion 71 from the recovery container 4 of the riser pipe 7, that is, in the upper portion 71 from the water surface of the treated water X. Therefore, in order to suppress the leakage of the air Y from the gas hood 44 due to the pressure loss in the riser pipe 7, it is most efficient to shorten the length of the upper portion 71 of the riser pipe 7.
That is, as in the dephosphorization apparatus 1 according to the present embodiment, the height of the upper portion 71 from the collection container 4 of the riser pipe 7, that is, the height of the upper portion 71 from the water surface of the water to be treated X By setting the height so as not to leak out, it is possible to further suppress the leakage of the air Y from the gas hood 44.
Then, the air Y that has risen along the riser pipe 7 together with a part of the water to be treated X is separated from the water to be treated X by the gas-liquid separator 8 and is exhausted to the outside of the dephosphorization device 1 through the ventilation line 24. Further, the water to be treated separated from the air Y by the gas-liquid separator 8 is supplied to the downer pipe 9.

To-be-treated water X supplied to the downer pipe 9 is supplied with magnesium and ammonium through a magnesium / ammonium supply line 25 installed in the middle of the downer pipe 9. Then, the to-be-processed water X is divided into the pipe | tube 91 and the pipe | tube 92, and is supplied to the reaction container 3 and the granulation container 2. FIG. Specifically, the treated water X having a predetermined flow rate is caused to flow into the pipe 92 by the pump 10 installed in the pipe 92, and the remaining treated water X flows into the pipe 91.
Here, the to-be-processed water X supplied to the reaction vessel 3 and the granulation vessel 2 through the pipes 91 and 92 is recovered by the recovery unit 41 and separated by the gas-liquid separator 8. Some still contain some phosphate compounds. For this reason, it is possible to promote the granulation of the phosphoric acid compound in the granulation container 2 by supplying the water to be treated X containing such a slight amount of the phosphoric acid compound to the granulation container 2, and this By supplying the to-be-treated water X containing some phosphoric acid compound to the reaction vessel 3, precipitation of the phosphoric acid compound in the reaction vessel 3 can be promoted.

Further, in the dephosphorization apparatus 1 according to the present embodiment, the magnesium / ammonium supply line 25 is installed in the middle of the downer tube 9 before branching, so that not only the reaction vessel 3 but also the granulation vessel 2 has magnesium. The to-be-processed water X containing an ion and ammonium ion can be supplied easily. Thus, by supplying the to-be-processed water X containing magnesium ion and ammonium ion to the granulation container 2, it becomes possible to further promote the granulation of a phosphoric acid compound.
As described above, the dephosphorization apparatus 1 according to this embodiment includes the separation / circulation means (the riser pipe 7, the gas-liquid separator 8, the downer pipe 9, the pipes 91 and 92, and the pump 10). It is possible to promote the precipitation of the phosphoric acid compound in 3 and promote the granulation of the phosphoric acid compound in the granulation container 2.
In addition, as described above, the pipe 91 is obliquely connected to the reaction container 3 so as to supply the water to be treated X from above to the reaction container 3, and the lower end of the stirring assist pipe 5. It is connected above 5a. For this reason, it can suppress that the to-be-processed water X supplied in the reaction container 3 via the pipe | tube 91 prevents the swirling flow S, and also suppresses the obstruction | occlusion of the pipe | tube 91 resulting from a phosphoric acid compound depositing. can do. Moreover, since the to-be-processed water X supplied into the reaction vessel 3 through the pipe 91 is stirred in the reaction vessel 3, magnesium ions and ammonium ions can be easily distributed throughout the reaction vessel 3. it can. Moreover, the pipe | tube 91 is connected with respect to the reaction container 3 from the tangent direction by planar view, as shown in FIG. For this reason, a swirling flow with the vertical direction as the central axis is formed in the reaction vessel 3. Therefore, since the to-be-processed water X in the reaction container 3 is further stirred, precipitation of a phosphoric acid compound can be promoted more. In addition, since the to-be-treated water supply line 22 for supplying the to-be-treated water X to the reaction vessel 3 from the outside is also connected to the reaction vessel 3 from the tangential direction in plan view, the vertical direction is the central axis. The swirl flow can be strengthened, and the treated water X in the reaction vessel 3 can be further stirred.
In addition, the flow rate of the to-be-processed water X supplied to the granulation container 2 through the pipe | tube 92 is granulated in the granulation container 2, and the phosphoric acid compound by which the particle size was about 1-2 mm was granulated. The flow rate is preferably such that it floats in the container 2. Moreover, the to-be-processed water supply line 22 connected with the granulation container 2 is also connected with respect to the granulation container 2 from the tangent direction by planar view. For this reason, a swirling flow with the vertical direction as the central axis is formed in the granulation vessel 2. For this reason, while the to-be-processed water X in the reaction container 3 is stirred, the residence time of the to-be-processed water X in the granulation container 2 becomes long, and granulation of the phosphoric acid compound in the granulation container 2 more efficiently. Can be performed.

  As mentioned above, although preferred embodiment of the dephosphorization apparatus based on this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above embodiment, the stirring assisting tube 5 is disposed in the reaction vessel 3 as the stirring means of the present invention, but the present invention is not limited to this, and the stirring means of the present invention may be a propeller or the like. A stirring device may be disposed in the reaction vessel 3. However, since the phosphoric acid compound is very easy to bond with a metal, when an apparatus having a sliding part or a driving source is arranged in the reaction vessel 3, it is not preferable because frequent inspection work is required. Therefore, it is preferable to dispose the stirring means having no sliding portion and a driving source in the reaction vessel 3 like the stirring assist pipe 5 shown in the above embodiment.

  Moreover, in the said embodiment, in order to ensure an air collection area, the cross-sectional area of collection container 4 itself was made larger than the cross-sectional area of reaction container 3. However, the cross-sectional area of the recovery part 41 of the recovery container 4 may be substantially the same as the cross-sectional area of the reaction container 3 as long as the phosphate compound does not reach the supernatant Z.

It is sectional drawing which showed schematic structure of the dephosphorization apparatus 1 which concerns on one Embodiment of this invention. It is the sectional view on the AA line in FIG. It is a perspective view of collection part 41 with which dephosphorization device 1 concerning one embodiment of the present invention is provided. It is a schematic diagram of the gas hood 44 with which the dephosphorization apparatus 1 which concerns on one Embodiment of this invention is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Dephosphorization device 2 ... Granulation container 3 ... Reaction container 4 ... Recovery container 41 ... Recovery part 42 ... Storage part 5 ... Stirring assistance pipe (stirring means, cylindrical tube)
6. Air diffuser (air supply means)
X …… Water to be treated Y …… Air Z …… Supernatant

Claims (6)

By blowing air in the presence of magnesium ions and ammonium ions into the water to be treated which contains phosphate ions and is supplied from the lower part of the apparatus, a phosphoric acid compound is precipitated from the water to be treated and dephosphorized. A dephosphorization device for discharging the supernatant liquid as treated water from the upper part of the device,
A granulation container arranged at the bottom of the apparatus and granulating the phosphoric acid compound inside, and
A reaction vessel arranged on the granulation vessel in communication with the granulation vessel and depositing the phosphate compound by blowing the air into the water to be treated inside;
A recovery container disposed on the reaction container in communication with the reaction container and recovering the air from the treated water inside;
Stirring means for stirring the water to be treated and the air in the reaction vessel ;
Separating / circulating means for separating the water to be treated collected together with the air and the air, and supplying the treated water after separation to the granulation vessel and the reaction vessel ,
The separation / circulation means raises the air collected in the collection container together with a part of the water to be treated and collects the riser pipe and the water to be treated and the air collected together with the air. A gas-liquid separator, and a downer pipe for supplying the treated water after separation to the granulation container and the reaction container, wherein the height of the riser pipe above the treated water surface is from the recovery container. The dephosphorization device is set so that the air does not leak out . 2. The dephosphorization apparatus according to claim 1, wherein the stirring means is a cylindrical tube having an end portion spaced apart from the granulation container and the recovery container by a predetermined distance and coaxially arranged with the reaction container. . The dephosphorization apparatus according to claim 2, further comprising an air supply unit that is disposed below the cylindrical tube and blows the air toward the inside of the cylindrical tube. The said granulation container and the said reaction container are arrange | positioned coaxially, The container diameter of the said reaction container is made larger diameter than the container diameter of the said granulation container, The Claim 2 or 3 characterized by the above-mentioned. Dephosphorization device. The recovery container includes a recovery unit that recovers the air from the treated water, and a storage unit that is disposed on the recovery unit and stores the treated water from which the air has been recovered by the recovery unit. 5. The dephosphorization device according to claim 1, wherein at least the recovery section of the recovery container has a cross-sectional area set wider than that of the reaction container . The dephosphorization device according to any one of claims 1 to 5, wherein a cross section of the recovery container is set in a rectangular shape .

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