JP2022008913A - Processing method of liquid to be treated of and processing apparatus of liquid to be treated - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method of a liquid to be treated and a processing apparatus of a liquid to be treated, capable of suppression of formation of a short circuit flow to make flow conditions of a reaction tank more uniform and growing crystal grains of poorly-soluble salt to a size suitable for recovery while suppressing drain of an unreacted liquid to be treated and fine crystal grains to outside of the apparatus.

SOLUTION: The processing method of a liquid to be treated includes: allowing a liquid 2 to be treated to flow upwardly in a reaction tank 1 and to contact with a grain flowing in the reaction tank 1 for precipitation of an ion to be removed in the liquid 2 to be treated as crystals of poorly-soluble salt; withdrawing a part of the treated water in the reaction tank 1; and, by using the treated water withdrawn from the reaction tank 1 as a tower circulation liquid, and in a manner to form a rotational flow in the reaction tank 1, supplying a liquid containing the tower circulation liquid, the liquid 2 to be treated and an ion reactive with the ion to be removed from the lower part of the reaction tank 1 in a tangential direction with respect to a cross section of the reaction tank 1.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a method for treating a liquid to be treated and a device for treating the liquid to be treated, and in particular, a liquid to be treated for precipitating and removing ions to be removed such as phosphorus contained in the liquid to be treated by a crystallization reaction. The present invention relates to a treatment method and a treatment apparatus for a liquid to be treated.

A reaction tank is known for reacting an object to be treated containing a phosphate ion with a magnesium compound to recover phosphorus in the object to be treated as solid particles of magnesium ammonium phosphate (MAP) crystals.

For example, Japanese Patent Application Laid-Open No. 2016-175083 (Patent Document 1) has a double-cylinder structure in which a tubular reaction cylinder is provided inside the reaction tower, and covers the inner cylinder portion which is an upward flow. It is described that MAP crystals are granulated in the reaction cylinder by charging the treatment liquid and circulating the treatment liquid together with the magnesium salt and the alkaline agent injected from the upper part of the reaction cylinder.

In Japanese Patent No. 4101506 (Patent Document 2), water to be treated, a liquid containing ions that react with ions to be removed (here, magnesium ions), and a part of the treated water are described from the lower part of the fluidized bed type crystallization reaction tank. A structure for supplying circulating water and removing ions to be removed in the water to be treated is described.

In JP-A-11-267665 (Patent Document 3), raw water is introduced into the lower part of the reaction tower, the treated water is taken out from the upper part of the reaction tank, and a part of the treated water is taken out from the upper part of the reaction tower by a circulation means. In the derinsing device that circulates to the lower part, a storage section having a horizontal cross-sectional area smaller than the horizontal cross-sectional area of the reaction tower is provided at the lower part of the reaction tower, and water is circulated to the storage section by a circulation means. Examples of phosphorus devices are described.

Japanese Unexamined Patent Publication No. 2016-175083 Japanese Patent No. 4101506 Japanese Unexamined Patent Publication No. 11-267665

However, when the reaction tank described in Patent Document 1 is used, it is difficult to properly mix the liquid to be treated with the magnesium salt and the alkaline agent. If the upward flow velocity is increased in order to improve the mixed state, there is a concern that unreacted water to be treated may flow out.

In the invention described in Patent Document 2, a liquid bed containing water to be treated and a liquid containing ions that react with removed ions (here, a liquid containing magnesium ions) and a part of circulating water of the treated water are charged in a fluidized bed type crystallization reaction tank. It has a structure to supply. Both the water to be treated and the liquid containing ions that react with the ions to be removed flow in from the lower part of the reaction tank, and the MAP is crystallized on the surface of the crystal particles while flowing the crystal particles. It is easy to mix, and the risk that the water to be treated flows out unreacted can be reduced.

However, when a reaction vessel as described in Patent Document 2 is used, the water to be treated and the liquid containing the ions that react with the ions to be removed are mixed immediately after being supplied into the reaction vessel, so that the crystals are mixed. There is a concern that fine particles cannot grow to a size suitable for recovery and will flow out to the outside of the device. In addition, if the crystal particles do not flow properly in the reaction tank, the crystal particles stick to each other, and the liquid containing the ions that react with the water to be treated and the ions to be removed cannot react on the particle surface and flows out of the reaction tank as a short-circuit flow. There is also a concern.

In the invention described in Patent Document 3, by circulating a part of the treated water to the storage portion at the bottom of the reaction tank, the stored MAP particles are solidified and easily pulled out from the bottom of the reaction tower. However, as in Patent Document 1, it is difficult to properly mix the liquid to be treated with the magnesium salt and the alkaline agent in the first place, and there is no reaction when the flow velocity of the upward flow is increased for mixing. The liquid to be treated may flow out.

In view of the above problems, the present invention can suppress the generation of a short-circuit flow to make the flow state in the reaction vessel more uniform, and prevent the unreacted liquid to be treated and fine crystal particles from flowing out to the outside of the apparatus. Provided are a method for treating a liquid to be treated and a device for treating the liquid to be treated, which can grow crystal particles of a poorly soluble salt to a size suitable for recovery while suppressing the pressure.

As a result of diligent studies by the present inventors in order to achieve the above object, the treated water is withdrawn from the reaction vessel, and the drawn treated water is used as the circulating fluid in the column to generate a swirling flow in the reaction vessel. It is one of the effective means to supply the circulating liquid in the column, the liquid to be treated, and the liquid containing ions that react with the ions to be removed from the lower part of the reaction tank in the tangential direction with respect to the cross section of the reaction tank. I understand.

The method for treating the liquid to be treated according to the embodiment of the present invention completed based on the above findings is one aspect in which the liquid to be treated is passed through the reaction vessel by an upward flow and the particles flow in the reaction vessel. By contacting with, the ions to be removed in the liquid to be treated are precipitated as crystals of a sparingly soluble salt, a part of the treated water in the reaction tank is withdrawn, and the treated water drawn from the reaction tank is drawn from the column. A liquid containing ions that react with the circulating liquid in the column, the liquid to be treated, and the ions to be removed is applied from the lower part of the reaction tank to the cross section of the reaction tank so as to be an internal circulating liquid and generate a swirling flow in the reaction tank. This is a method for treating a liquid to be treated, which includes supplying the liquid in the tangential direction.

In one embodiment, the method for treating the liquid to be treated according to the embodiment of the present invention is a swirling flow in order from the liquid containing the circulating liquid in the column, the liquid to be treated, and the liquid containing ions that react with the ions to be removed, in descending order of the flow velocity. So that the total flow velocity of the liquid containing the ions that react with the circulating liquid in the column, the liquid to be treated, and the ions to be removed is larger than the length of the outer circumference of the cross section of the reaction tank. Includes adjusting the flow velocity.

In another embodiment of the method for treating the liquid to be treated according to the embodiment of the present invention, as a reaction tank, a circulating liquid in a column, a liquid to be treated, and a liquid containing ions that react with ions to be removed are received to form crystals. Including the use of a reaction vessel having a reaction section for generation and a sedimentation separation section located above the reaction section and separating crystals generated in the reaction section by precipitating them into the reaction section. Extracting a part of the treated water includes extracting the treated water from a height of 30% or less from the lowermost end or the lowermost end of the sedimentation separation portion upward.

In still another embodiment, the method for treating the liquid to be treated according to the embodiment of the present invention draws out the supernatant of the treated water in the reaction tank obtained from above the sedimentation separation portion and reacts with the ions to be removed. It further includes mixing with a liquid containing ions and circulating it to the reaction part.

In still another embodiment, the method for treating the liquid to be treated according to the embodiment of the present invention includes setting the water flow rate of the reaction section to 25 to 60 m / H.

In still another embodiment, the method for treating the liquid to be treated according to the embodiment of the present invention includes two or more reaction tanks, and particles made of crystals of a sparingly soluble salt obtained in the first reaction tank are the first. This includes introducing the particles into the reaction tanks after the second reaction tank and returning the particles composed of the crystals of the sparingly soluble salt obtained in the reaction tanks after the second reaction tank to the first reaction tank.

The treatment device for the liquid to be treated according to the embodiment of the present invention has one side surface, in which the liquid to be treated is passed by an upward flow and brought into contact with particles flowing inside, so that the ions to be removed in the liquid to be treated are formed. A reaction tank that precipitates as crystals of poorly soluble salt, a drawing means for drawing out a part of the treated water in the reaction tank, and the treated water drawn out from the reaction tank as a circulating fluid in the column, and a swirling flow is created in the reaction tank. A plurality of supply pipes that supply the circulating liquid in the column, the liquid to be treated, and the liquid containing ions that react with the ions to be removed from the lower part of the reaction tank in a tangential direction with respect to the cross section of the reaction tank so as to generate the liquid. Be prepared.

According to the present invention, the generation of a short-circuit flow can be suppressed to make the flow state in the reaction vessel more uniform, and the unreacted liquid to be treated and fine crystal particles can be suppressed from flowing out to the outside of the apparatus. It is possible to provide a method for treating a liquid to be treated and an apparatus for treating the liquid to be treated, which can grow crystal particles of a sparingly soluble salt to a size suitable for recovery.

It is a schematic diagram which shows an example of the processing apparatus of the liquid to be treated which concerns on 1st Embodiment of this invention. It is sectional drawing explaining the connection position of the supply pipe which supplies the liquid containing an ion which reacts with a circulating liquid in a column, a liquid to be treated, and an ion to be removed. It is a schematic diagram which shows an example of the processing apparatus of the liquid to be treated which concerns on the 2nd Embodiment of this invention. It is a schematic diagram which shows an example of the processing apparatus of the liquid to be treated which concerns on 3rd Embodiment of this invention. FIG. 3 is a schematic cross-sectional view illustrating a connection position of a supply pipe for supplying a liquid containing an ion that reacts with a circulating liquid in a column, a liquid to be treated, and an ion to be removed in the processing apparatus shown in FIG. It is sectional drawing which explains the connection position of the conventional supply pipe to the reaction tank. It is a schematic diagram which shows an example of the processing apparatus of the liquid to be treated which concerns on 4th Embodiment of this invention. It is a schematic diagram which shows an example of the processing apparatus of the liquid to be treated which concerns on 5th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings below, the same or similar parts are designated by the same or similar reference numerals. It should be noted that the embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention describes the structure, arrangement, etc. of the components as follows. It is not specific to things.

(First Embodiment)
As shown in FIG. 1, the treatment apparatus for the liquid to be treated 2 according to the embodiment of the present invention is provided in the middle of the reaction tank 1 and the reaction tank 1 and draws out a part of the treated water in the reaction tank 1. The drawing means 16 and the treated water drawn from the reaction tank 1 are used as the circulating fluid in the column, and react with the circulating fluid in the column, the liquid to be treated 2, and the ions to be removed so as to generate a swirling flow in the reaction vessel 1. A plurality of supply pipes 21 and 22 for supplying a liquid containing ions from the lower part of the reaction tank 1 in the tangential direction with respect to the cross section of the reaction tank 1 are provided.

The reaction tank 1 allows the liquid to be treated 2 to pass in an upward flow and is brought into contact with the particles flowing in the reaction tank 1 to precipitate the ions to be removed in the liquid to be treated 2 as crystals of a sparingly soluble salt. It is a reaction tank. The reaction tank 1 is charged with particles (seed crystals) for crystallizing the ions to be removed on the surface thereof and a drug containing ions for reacting with the ions to be removed, using a pH meter (not shown) or the like. The inside of the reaction vessel 1 is maintained under conditions suitable for the crystallization reaction. The crystals of the sparingly soluble salt can be discharged to the outside through the pipe 24 connected to the bottom of the reaction tank 1.

As the reaction tank 1, for example, a fluidized bed type crystallization reaction tank in which the liquid to be treated is passed in an upward flow is used. By the crystallization reaction in the reaction tank 1, desired removed ions contained in the liquid to be treated 2, for example, phosphate ion, calcium ion, fluorine ion, carbonate ion, sulfate ion and the like are removed.

The reaction tank 1 receives the liquid to be treated 2, the liquid containing the ions that react with the ions to be removed in the liquid to be treated 2, and the circulating liquid in the column which is a part of the treated water drawn from the extraction means 16. It is provided with a reaction unit 11 for producing crystals of a sparingly soluble salt, and a sedimentation separation unit 12 located above the reaction unit 11 and precipitating and separating the crystals produced by the reaction unit 11 into the reaction unit 11. Here, the "circulating liquid in the column" represents an embodiment in which the treated water drawn from the reaction tank 1 is directly returned to the reaction tank 1. If necessary, a chemical such as a pH adjuster 5 may be added to the circulating fluid in the column.

In the example of FIG. 1, the reaction unit 11 includes a tapered portion whose cross-sectional area gradually increases toward the upper part of the reaction vessel 1 and a circular tubular portion continuous with the tapered portion. The sedimentation separation portion 12 is continuous with the tubular portion of the reaction portion 11, and includes a tapered portion whose cross-sectional area gradually increases toward the upper part of the reaction tank 1 and a circular tubular portion continuous with the tapered portion.

In the pulling means 16, the boundary portion between the tubular portion of the reaction portion 11 and the tapered portion of the sedimentation separation portion, which is the lowermost end B of the sedimentation separation portion 12, or the lowermost end B of the sedimentation separation portion 12 is 0% and the uppermost end T is 100. In the case of%, it is preferable that the connection is made to a height within 30% (30%) from the lowermost end B toward the upper side of the reaction tank 1. By connecting the extraction means 16 to such a position, the extraction means 16 has almost completed the crystallization reaction, but the sedimentation separation of the sparingly soluble crystals obtained by the crystallization reaction has not been completed. The treated water can be drawn out as circulating water in the tower. By using such treated water as circulating water in the column, the water flow rate in the lower part of the reaction tank 1 can be increased without inhibiting the crystallization reaction in the lower part of the reaction tank 1.

That is, the extraction means 16 is configured to extract the treated water in the reaction tank 1 from a height within 30% upward from the lowermost end B or the lowermost end B of the sedimentation separation portion 12 by the pump 61. By making the extraction position of the extraction means 16 appropriate, the unreacted liquid to be treated and fine particles are not significantly changed from the upper part of the reaction tank 1 even if the circulation flow rate of the circulating fluid in the column is increased. The outflow of the crystal particles to the outside of the apparatus can be suppressed, and the crystal particles of the sparingly soluble salt can be grown to a size suitable for recovery.

If the drawing position of the treated water by the drawing means 16 is too low, the seed crystals inserted in the reaction unit 11 may be pulled out, which may cause troubles such as blockage in the drawing means 16 or the pump 61. On the other hand, if the drawing position of the treated water by the drawing means 16 is too high, the flow rate ascending to the settling separation section 12 increases, and it is necessary to increase the shape of the settling separation section 12 in order to optimally settle and separate them. , There may be a concern that it will lead to an increase in equipment cost. The drawing position of the treated water by the drawing means 16 is more preferably connected to a height in the range of 20% from the lowermost end B of the settling separation section 12, and is set to the height of the lowermost end B of the settling separation section 12. Is more preferable.

A plurality of supply pipes 21 and 22 are connected to the lower part of the reaction unit 11 of the reaction tank 1. In the example of FIG. 2, three supply pipes 21, 22 and 23 for supplying the liquid containing the circulating liquid in the column, the liquid to be treated 2 and the ion to react with the ion to be removed into the reaction tank 1 are the reaction tank 1. The supply pipe 21, the supply pipe 22, and the supply pipe 23 are connected in this order from the upstream side of the swirling flow. The liquid containing the circulating liquid in the column, the liquid to be treated 2, and the liquid containing ions that react with the ions to be removed are connected to the supply pipes 21, 22, and 23 on the upstream side of the swirling flow in order from the liquid having the highest flow velocity. ..

Of the liquids containing the circulating liquid in the column, the liquid to be treated 2, and the ions that react with the ions to be removed, the liquids having the highest flow velocity are connected to the supply pipes 21, 22, and 23 on the upstream side of the swirling flow in order to swirl. The flow of the flow can be sustained for a longer period of time, and the particles flowing in the reaction section 11 of the reaction vessel 1 can be made to flow more uniformly.

The supply pipes 21, 22 and 23 are connected to the reaction tank 1 at substantially the same height in the horizontal direction, but they may be connected with a slight vertical deviation. It is preferable that the supply pipes 21, 22 and 23 are arranged at positions where the coarse particles deposited in the tapered portion of the reaction unit 11 can flow. As a result, the particles at the bottom of the reaction unit 11 can be made to flow and the adhesion between the particles can be suppressed.

The total flow velocity of the circulating liquid in the column, the liquid to be treated, and the liquid containing the ions that react with the ions to be removed is the outer circumference of the cross-sectional CS (see FIG. 2) of the reaction tank 1 to which the supply pipes 21, 22, and 23 are connected. It is preferable that each flow velocity is adjusted so as to be larger than the length (total length) of. When particles of 0.2 to 1.0 mm are allowed to flow in the reaction tank 1, and a liquid containing ions that react with the circulating liquid in the column, the liquid to be treated, and the ions to be removed is horizontally supplied into the reaction tank 1. The time for the horizontal flow to stall and the liquid flow to become an upward flow is approximately 0.1 to 0.3 seconds.

Considering the stall time of the horizontal liquid flow in the lower part of the reaction tank 1, the total flow velocity of the circulating liquid in the column, the liquid to be treated 2, and the liquid containing the ions that react with the ions to be removed is the length of the outer circumference of the cross section CS. It is preferable to adjust the flow rate of each liquid so as to be larger than that, more preferably 1 to 8 times, in another embodiment 1 to 2 times, and still 4 times to 6 times. As a result, a more uniform flow state can be achieved without generating a dead zone in which the liquid and particles in the reaction vessel 1 do not flow, and the crystal particles of the poorly soluble salt grow to a size suitable for recovery. This makes it possible to improve the removal rate of ions to be removed in the liquid to be treated.

It is preferable that the three supply pipes 21, 22 and 23 are arranged close to each other. Although not limited to the following, the inflow direction X of the liquid in the supply pipe 21 arranged on the most downstream side of the swirling flow and the inflow direction Y of the liquid in the supply pipe 23 arranged on the most upstream side of the swirling flow. Is 180 ° different as in the case of the supply pipe 21 shown by the solid line in FIG. 2, or is arranged on the most downstream side of the swirling flow as in the case of the supply pipe 21 shown by the dotted line in FIG. The angle θ formed by the liquid inflow direction X of the supply pipe 21 and the liquid inflow direction Y of the supply pipe 23 arranged counterclockwise from X is preferably 180 ° or less, more preferably 150 °. It is preferable that the supply pipes 21, 22 and 23 are arranged close to each other so as to be less than or equal to, more preferably 120 ° or less, and further preferably 100 ° or less. By arranging the supply pipes 21, 22 and 23 close to each other, a strong swirling flow can be generated along the outer periphery of the cross section of the reaction tank 1 in the vicinity of the inflow portion of each liquid, and the inside of the reaction tank 1 can be generated. A more uniform flow state can be achieved without creating a dead zone in which the liquid and particles do not flow.

In the treatment apparatus shown in FIG. 1, a liquid containing ions that react with the circulating liquid in the column, the liquid to be treated, and the ions to be removed so that the water flow rate of the reaction unit 11 of the reaction tank 1 is 10 to 80 m / H. Adjust each flow velocity. The water flow rate is more preferably adjusted to 10 to 70 m / H, more preferably 25 to 60 m / H, and even more preferably 25 to 40 m / H.

The liquid containing the ions that react with the ions to be removed is adjusted in the treatment tank 3 and supplied into the reaction tank 1 from the supply pipes 21, 22 and 23 (supply pipe 22 in FIG. 1) via the pump 62. .. When it is desired to remove ions 4 that react with the ions to be removed in the treatment tank 3, for example, phosphorus in the liquid to be treated in the reaction tank 1, magnesium ions are added via an addition means (not shown). Magnesium ions are preferably added as magnesium hydroxide or magnesium chloride. Further, a pH adjuster 5 for adjusting the pH of the liquid in the reaction vessel 1 is added via an addition means (not shown). The pH adjuster 5 may be added to the liquid to be treated 2 or may be added to the circulating liquid in the column.

Although not shown, it is also possible to supply a gas to the lower part of the reaction vessel 1 and allow particles composed of crystals of a sparingly soluble salt to flow in the lower part of the reaction vessel 1. Since particles with a large particle size tend to settle and do not flow easily, a swirling flow is sufficient simply by supplying a liquid containing ions that react with the water to be treated, the circulating liquid in the column, and the ions to be removed to the lower part of the reaction tank 1. Since it may not be possible to obtain it, by supplying a gas such as compressed air from the lower part of the reaction tank 1, it becomes easy to create an appropriate swirling flow and a flow state of particles and liquid in the reaction tank 1. ..

In the conventional crystallization reaction tank, as shown in FIG. 6, the connection position of the supply pipes 211 and 221 to the reaction tank 1 is a circular reaction tank along a cross section perpendicular to the height direction of the reaction tank 1. It was connected so as to be perpendicular to the tangential direction of the cross section. Therefore, the liquid supplied into the conventional crystallization reaction tank is mixed immediately after being supplied into the crystallization reaction tank to generate fine particles, and these fine particles ride on the upward flow inside the tank. In some cases, the particles were discharged to the outside of the crystallization reaction tank.

Further, in the conventional crystallization reaction tank, the liquid containing the water to be treated and the ion to be removed and the supernatant obtained by the treatment in the crystallization reaction tank are circulated to the reaction tank 1. As a result, a method has been adopted in which the mixture is poured from the lower part of the reaction vessel 1 and diluted so that the inside of the reaction vessel 1 has an ion product suitable for crystallization.

However, if the amount of circulating water in the supernatant is increased, the treated water in which the sedimentation treatment of the particles has not been completely completed may be drawn out in the sedimentation separation section 12, and the recovery efficiency of the crystal particles may not be sufficiently high. be. On the other hand, in order to use the supernatant obtained by completely completing the sedimentation treatment of the particles in the sedimentation separation unit 12 and to secure a circulating water amount sufficient to generate a swirling flow in the lower part of the reaction tank 1. Since the volume of the settling separation portion 12 must be increased, the size of the device is increased. Therefore, it is difficult to properly flow the lower part of the reaction tank 1 only by circulating the supernatant liquid in the lower part of the reaction tank 1.

According to the method for treating the liquid to be treated and the treatment apparatus according to the first embodiment of the present invention, the treated water is withdrawn from the reaction tank 1, and the drawn treated water is used as the circulating liquid in the column, and the inside of the reaction tank 1 is used. A liquid containing an ion that reacts with the circulating liquid in the column, the liquid to be treated 2, and the ion to be removed is supplied from the lower part of the reaction tank 1 in the tangential direction with respect to the cross section of the reaction tank 1 so as to generate a swirling flow. At the same time, the liquid is supplied to the upstream side of the swirling flow in order from the liquid having the highest flow velocity. As a result, it is possible to reliably generate a swirling flow by the reaction unit 11 of the reaction tank 1 without increasing the size of the apparatus, and to make the flow state of the liquid and the flowing particles of the reaction unit 11 of the reaction tank 1 uniform. ..

Further, by drawing out the treated water near the lowermost end B of the sedimentation separation unit 12 immediately above the reaction unit 11 where the crystallization reaction of the reaction tank 1 proceeds, the reaction unit 11 of the reaction tank 1 is further extracted by the extraction means 16. It is possible to secure the linear velocity (LV) of the upward flow required for the uniform flow of particles in. As a result, the crystal particles of the poorly soluble salt produced in the reaction unit 11 can be grown to a size suitable for recovery, and the removal rate of the ions to be removed in the liquid to be treated can be improved.

(Second embodiment)
As shown in FIG. 3, the treatment device for the liquid to be treated according to the second embodiment of the present invention includes a circulation means 25 for circulating the supernatant liquid obtained from above the sedimentation separation unit 12 to the treatment tank 3. Further, it is different from the processing apparatus shown in FIG. Others are substantially the same as the processing apparatus of FIG. 1, and the description thereof will be omitted.

A part of the supernatant liquid circulated by the circulation means 25 is supplied to the treatment tank 3 and resupplied to the lower part of the reaction tank 1 via the supply pipes 21, 22 and 23 via the pump 62. According to the treatment apparatus and treatment method for the liquid to be treated according to the second embodiment, the liquid containing ions that react with the ions to be removed can be diluted by mixing the supernatant liquid, so that the liquid to be treated 2 When the phosphorus concentration is high, a diluted solution can be prepared in the treatment tank 3 and supplied to the reaction tank 1, and the treatment can be proceeded without adding new diluted water. Further, since the unreacted ions to be removed remaining in the supernatant can be more reliably removed in the reaction tank 1, the recovery efficiency of the ions to be removed is further improved.

The supernatant liquid supplied as diluted water into the treatment tank 3 is circulating water for generating a swirling flow to the lower part of the reaction tank 1 because the sedimentation treatment of the particles is almost completely completed in the sedimentation separation unit 12. It can also be used as. However, it may be difficult to secure an LV for generating a swirling flow in the lower part of the reaction unit 11 only by circulating the supernatant liquid supplied as the diluted water from the treatment tank 3 to the reaction unit 11. In order to supplement the LV sufficient to generate a swirling flow in the lower part of the reaction unit 11 with the supernatant, it is necessary to supply more than the amount of the supernatant required as the diluted water, that is, the sedimentation separation unit. Although it is necessary to increase the size of 12, the apparatus may become large and stable sedimentation separation may not be possible.

In the treatment device for the liquid to be treated according to the second embodiment of the present invention, the treated water in which the crystallization reaction is completed but the sedimentation separation is not completed is drawn out by the drawing means 16 and used as the circulating water in the column. In addition to circulating to 11, the supernatant liquid circulated by the circulation means 25 is further mixed with a liquid containing ions that react with the ions to be removed in the treatment tank 3, and the mixed liquid is mixed with the liquid containing the ions to react with the ions to be removed, and the mixed liquid is mixed with the supply pipe 21 via the pump 62. , 22 and 23 are re-supplied to the lower part of the reaction vessel 1.

As a result, the LV of the reaction unit 11 can be more reliably secured without increasing the size of the sedimentation separation unit 12, and the sedimentation separation treatment of the treated water in the sedimentation separation unit 12 can be stably performed. The supply amount of the liquid containing the ions that react with the ions to be removed, including the circulating water in the column circulated to the reaction unit 11 and the above-mentioned supernatant liquid circulated to the reaction unit 11, is 9: 1 or more in volume ratio. It is preferable to adjust the ratio to 6: 4 and more preferably 9: 1 to 7: 3 to supply to the lower part of the reaction unit 11.

(Third embodiment)
As shown in FIG. 4, in the device for treating the liquid to be treated according to the third embodiment of the present invention, the drawing means 16 is connected to a pipe for supplying the liquid to be treated 2 to the reaction tank 1, and the drawing means It differs from the processing apparatus shown in FIG. 3 in that the circulating fluid in the column drawn by 16 can be merged with the liquid to be treated 2 before flowing into the reaction vessel 1. Others are substantially the same as the processing apparatus of FIG. 3, and the description thereof will be omitted.

According to the treatment apparatus and treatment method for the liquid to be treated according to the third embodiment, as shown in FIG. 5, since the supply pipes 21 and 22 to be supplied to the reaction tank 1 need only be two, the supply pipe 21 The number of 22 can be reduced to reduce the size and simplification of the device. In the example of FIG. 5, the supply directions of the supply pipes 21 and 22 differ by about 180 °, but in order to surely generate a larger swirling flow in the reaction vessel 1, as shown in FIG. Of course, the supply pipes 21 and 22 may be arranged close to each other.

(Fourth Embodiment)
As shown in FIG. 7, the treatment apparatus for the liquid to be treated according to the fourth embodiment is different from the treatment apparatus shown in FIGS. 1 to 5 in that it includes two or more reaction tanks 1. That is, the processing apparatus shown in FIG. 7 includes two reaction tanks 1 and 7, and particles composed of crystals of a sparingly soluble salt obtained in the reaction tank 1 (first reaction tank) are put into the reaction tank 7 (second reaction tank). The particles made of crystals of the sparingly soluble salt obtained in the reaction vessel 7 can be returned to the reaction vessel 1 by introducing the particles into the reaction vessel (1).

The reaction vessel 7 can have substantially the same configuration as the reaction vessel 1. In the lower part of the reaction tank 7, supply pipes 71 and 72 for supplying a liquid containing an ion to react with the liquid to be treated 2, the circulating liquid in the column, and the ion to be removed can be provided. These supply pipes 71 and 72 are also connected in the tangential direction to the cross section of the reaction tank 7, and the liquid to be treated 2, the circulating liquid in the column, and the ions to be removed are tangential to the cross section of the reaction tank 7. A liquid containing ions that react with can be supplied.

The reaction tank 7 is also provided with a drawing means 76 for drawing the treated water from the reaction section of the reaction tank 7. The treated water drawn through the pump 81 is supplied from the lower part of the reaction tank 7 as circulating water in the column.

The supernatant liquid of the reaction tank 7 can be supplied to the treatment tank 3 via the pipe 75. In the treatment tank 3, ions 4 that react with the ions to be removed are added and supplied to the reaction tanks 1 and 7 from the lower part of the reaction tanks 1 and 7 via the pipe 35. The crystal particles settled in the treatment tank 3 can be returned to the reaction tank 7 via the pipe 34. The crystal particles obtained in the reaction tank 7 can be supplied to the reaction tank 1 via the pipe 74. According to the treatment apparatus and treatment method for the liquid to be treated according to the fourth embodiment, the removal rate of the ions to be removed can be further improved by arranging two or more reaction tanks 1 and 7.

(Fifth Embodiment)
As shown in FIG. 8, in the treatment apparatus for the liquid to be treated according to the fifth embodiment, the particles obtained in the reaction tanks 1 and 7, respectively, are discharged to the outside of the reaction tanks 1 and 7, respectively. Possible air lift pipes 50a and 50b are arranged, respectively.

The air lift pipes 50a and 50b include wash water receiving portions 52a and 52b for receiving wash water for washing the air lift pipes 50a and 50b, and valves and 51a and 51b provided below the wash water receiving portions 52a and 52b. , A liquid containing particles connected to the bubble separation portions 53a and 53b provided above the washing water receiving portion and the bubble separation portions 53a and 53b and having bubbles separated in the bubble separation portions 53a and 53b is put into the reaction tank 1. , 7 is provided with a slurry discharging unit 54a, 54b for discharging to the outside.

A circulating water return pipe 39 is connected to the washing water receiving portions 52a and 52b, and it is possible to use a part of the circulating water of the treated water of the reaction tanks 1 and 7 as the washing water. Alternatively, fresh water may be supplied from the washing water receiving portions 52a and 52b and supplied as the still water washing water. The air lift pipe 50b can supply the particles obtained in the reaction tank 7 into the reaction tank 1. The air lift pipe 50a can discharge the particles obtained in the reaction tank 1 to the outside of the reaction tank 1.

According to the treatment apparatus and treatment method for the liquid to be treated shown in FIG. 8, it is possible to further suppress the outflow of fine crystal particles to the outside of the apparatus, and the cleaning and maintenance work of the apparatus becomes easy.

Although the present invention has been described in accordance with the above embodiments, the statements and drawings that form part of this disclosure should not be understood as limiting the invention. The treatment apparatus and treatment method for the liquid to be treated according to the embodiment of the present invention can be modified in various ways from the present disclosure, and can be modified and embodied in the implementation stage without departing from the gist thereof. Is.

Examples of the present invention are shown below together with comparative examples, but these examples are provided for a better understanding of the present invention and its advantages, and are not intended to limit the invention.

In a fluidized bed type simulated crystallization reaction tank imitating the reaction tank 1 shown in FIG. 1, a drawing means is connected to the lowermost end of the precipitation separation part, and the treated water drawn from the simulated crystallization reaction tank is circulated in the column. It was prepared as a liquid, and a liquid to be treated containing phosphorus was treated.

Magnesium ions and a pH adjuster are added in the treatment tank 3 to prepare a liquid suitable for supply to the simulated crystallization reaction tank, and 0.2 to 1.0 mm magnesium ammonium phosphate crystal particles flow. The liquid to be treated, the liquid containing magnesium ions, and the circulating liquid in the column were supplied in the tangential direction from the lower part of the side surface of the simulated crystallization reaction tank.

The water flow rate of the reaction part in the simulated crystallization reaction tank was changed as shown in Table 1. The liquid to be treated, the liquid containing magnesium ions, and the circulating liquid in the column were supplied to the reaction section in descending order of the flow velocity, so as to be connected to the supply pipe on the upstream side in the direction of generating the swirling flow. The flow state in the simulated crystallization reaction tank was observed. The results are shown in Table 1.

In Table 1, "Δ1" indicates a case where a swirling flow did not occur in the reaction section and the inflow liquid caused a short-circuit flow. “Δ2” indicates a case where a swirling flow was generated in the reaction section, but the inflow liquid slightly caused a short-circuit flow. “◯” indicates that the flow of the reaction part was uniform and appropriate, and the outflow of magnesium phosphate filled in the reaction part from the upper layer of the reaction tank could be suppressed, but a slight amount of magnesium phosphate flowed out from the upper layer. “⊚” indicates a state in which the flow of the reaction vessel is uniform and appropriate, the water flow rate is appropriate, and the outflow of magnesium ammonium phosphate filled in the reaction unit does not occur.

1 ... Reaction tank 2 ... Liquid to be treated 3 ... Treatment tank 5 ... pH adjuster 7 ... Reaction tank 11 ... Reaction unit 12 ... Precipitation separation unit 16 ... Extraction means 21, 22, 23 ... Supply pipe 24 ... Piping 25 ... Circulation means 34 ... Piping 35 ... Piping 39 ... Circulating water return pipes 50a, 50b ... Air lift pipes 52a, 52b ... Washing water receiving parts 53a, 53b ... Bubble separation parts 54a, 54b ... Slurry discharge parts 61, 62 ... Pump 71 ... Supply pipe 74 , 75 ... Piping 76 ... Pulling out means

Claims (5)

A seed crystal that accepts the liquid to be treated, the liquid containing ions that react with the ions to be removed in the liquid to be treated, and the circulating liquid in the column and passes water in an upward flow, and the liquid to be treated flows inside. The reaction section, which precipitates the ions to be removed in the liquid to be treated as crystals of a sparingly soluble salt by contacting with the contained particles, and the crystals located above the reaction section and generated in the reaction section are subjected to the reaction. A reaction vessel provided with a sedimentation separation section that is settled into a section and separated.
A drawing means connected to a height of 30% or less from the lowermost end of the sedimentation separation portion or upward from the lowermost end, and drawing out a part of the treated water in the reaction tank as the circulating liquid in the column.
A liquid containing the circulating liquid in the column, the liquid to be treated, and the liquid containing ions that react with the ions to be removed is discharged from the lower part of the reaction tank so as to be connected to the reaction unit and generate a swirling flow in the reaction tank. A plurality of supply pipes that supply tangentially to the cross section of the reaction vessel,
A liquid to be treated provided with a circulation means for drawing out the supernatant liquid in the reaction tank obtained from above the sedimentation separation portion, mixing it with a liquid containing ions that react with the ions to be removed, and circulating the liquid in the reaction tank. Processing equipment. A seed crystal that accepts the liquid to be treated, the liquid containing ions that react with the ions to be removed in the liquid to be treated, and the circulating liquid in the column and passes water in an upward flow, and the liquid to be treated flows inside. The reaction section, which precipitates the ions to be removed in the liquid to be treated as crystals of a sparingly soluble salt by contacting with the contained particles, and the crystals located above the reaction section and generated in the reaction section are subjected to the reaction. A reaction vessel provided with a sedimentation separation section that is settled into a section and separated.
A drawing means connected to a height of 30% or less from the lowermost end of the sedimentation separation portion or upward from the lowermost end, and drawing out a part of the treated water in the reaction tank as the circulating liquid in the column.
A liquid containing the circulating liquid in the column, the liquid to be treated, and the liquid containing ions that react with the ions to be removed is discharged from the lower part of the reaction tank so as to be connected to the reaction unit and generate a swirling flow in the reaction tank. A plurality of supply pipes that supply tangentially to the cross section of the reaction vessel,
A device for treating a liquid to be treated, which comprises an addition means for supplying a drug to the circulating liquid in the column. By passing water through the reaction vessel having seed crystals in an upward flow and bringing it into contact with the particles flowing in the reaction vessel, the ions to be removed in the solution to be treated are used as crystals of a sparingly soluble salt. Precipitating and
By drawing out a part of the treated water in the reaction tank,
The treated water drawn out from the reaction vessel is used as the circulating fluid in the column, and contains the circulating fluid in the column, the liquid to be treated, and ions that react with the ions to be removed so as to generate a swirling flow in the reaction vessel. The liquid is supplied from the lower part of the reaction vessel in the tangential direction with respect to the cross section of the reaction vessel.
The reaction tank is located above the reaction section and a reaction section for receiving the circulating fluid in the column, the solution to be treated, and the solution containing ions that react with the ions to be removed to generate the crystals. Using a reaction vessel provided with a settling and separating section for precipitating and separating the crystals generated in the reaction section in the reaction section.
The supernatant liquid in the reaction vessel obtained from above the sedimentation separation part is drawn out, mixed with a liquid containing ions that react with the ion to be removed, and circulated to the reaction part.
Including
Extracting a part of the treated water in the reaction vessel includes extracting the treated water from the lowermost end of the sedimentation separation portion or from a height within 30% upward from the lowermost end.
A method for treating a liquid to be treated, wherein the ion to be removed contains any one of phosphate ion, calcium ion, fluorine ion, carbonate ion and sulfate ion. By passing water through the reaction vessel having seed crystals in an upward flow and bringing it into contact with the particles flowing in the reaction vessel, the ions to be removed in the solution to be treated are used as crystals of a sparingly soluble salt. Precipitating and
By drawing out a part of the treated water in the reaction tank,
The treated water drawn out from the reaction vessel is used as the circulating fluid in the column, and contains the circulating fluid in the column, the liquid to be treated, and ions that react with the ions to be removed so as to generate a swirling flow in the reaction vessel. The liquid is supplied from the lower part of the reaction vessel in the tangential direction with respect to the cross section of the reaction vessel.
The reaction tank is located above the reaction section and a reaction section for receiving the circulating fluid in the column, the solution to be treated, and the solution containing ions that react with the ions to be removed to generate the crystals. Using a reaction vessel provided with a settling and separating section for precipitating and separating the crystals generated in the reaction section in the reaction section.
Including adding a drug to the circulating fluid in the column,
Extracting a part of the treated water in the reaction vessel includes extracting the treated water from a height within 30% from the lowermost end of the sedimentation separation portion or the lowermost end upward. Processing method. The claim comprising adjusting the supply amount of the liquid containing the ion to react with the ion to be removed and the circulating water in the column supplied to the reaction unit to be 9: 1 to 6: 4 in volume ratio. 3. The method for treating a liquid to be treated according to 3.

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