JP4892212B2 - Reaction crystallizer - Google Patents

Description

  The present invention removes phosphate phosphorus from a reaction crystallization treatment apparatus, particularly sewage or industrial wastewater, which removes and recovers the target component contained in the water to be treated by precipitation on the surface of the seed crystal by a crystallization method. The invention relates to a reactive crystallization treatment technique to be recovered.

For example, as a dephosphorization method of treated water containing phosphorus such as sewage treated water, sludge is generated less than the coagulation method, and the final product can be recovered as a phosphorus resource and reused. A crystallization dephosphorization method (reaction crystallization treatment method) has attracted attention. In the crystallization reaction, phosphorus in the water to be treated is precipitated as hardly soluble hydroxyapatite. The solubility product of hydroxyapatite is extremely small (Ksp = 10 ⁻⁵⁶ ), and treated water with a low phosphorus concentration can be obtained.

The basic principle of removal and recovery of phosphate phosphorus (hereinafter referred to as PO ₄ -P) in wastewater by this method is that calcium phosphate (hydroxyapatite; HAp) is seeded by the reaction shown in the following formula (1). It is made to deposit on the surface of. Therefore, depending on the PO ₄ -P concentration, the calcium ion (Ca ²⁺ ) concentration, the pH that is the hydroxide ion (OH ⁻ ) concentration in the target waste water, and the PO ₄ -P concentration of the target treated water, Add the required amount of calcium ions (calcium agent) and hydroxide ions (alkali agent).
10Ca ²⁺ + 2OH ⁻ + 6PO ₄ ³⁻ → Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ (1)

Conventionally, for example, Patent Document 1 is known as a crystallization reaction apparatus.
Patent Document 1 ejects a mixture of treated water and treated water after crystallization treatment of the treated water as an upward flow from a pressure chamber provided in the lower part of the reaction tank, A fluidized bed in which a plurality of seed crystal grains are suspended is formed above the distributor. In addition, by supplying a chemical solution (calcium agent, alkaline agent solution) to the fluidized bed, the exclusion target component contained in the water to be treated is crystallized on the surface of the seed crystal grains.
The specific control of the crystallization reaction according to Patent Document 1 is performed by adding an alkali agent so as to keep the pH in the reaction tank constant. The target value for pH control at this time is approximately pH 9.5 to pH 12, although it varies depending on the PO ₄ -P concentration of the treated water.
JP 2002-301480 A

However, when removing phosphorus in waste water according to Patent Document 1, not all phosphate ions are deposited on the surface of the seed crystal. That is, some phosphate ions are precipitated as aggregates of fine calcium phosphate in a liquid away from the seed crystal. Aggregates are discharged without leaving the surface of the seed crystal while floating in the treated water. The amount of such agglomerates generated depends on the PO ₄ -P concentration, calcium ion concentration and pH in the water to be treated, which is the potential for precipitation of the calcium phosphate compound, as well as the water temperature, seed crystal loading, contact time and reaction. It also changes depending on the type of device.

Conventionally, in the proposed crystallization reaction treatment method, even if operation control conditions are optimized for low concentration phosphorus-containing wastewater (PO ₄ -P concentration is about 1 to 3 mg / L (liter)), The limit was to reduce the amount of aggregates generated to about 0.3 to 0.5 mg-P / L. That is, phosphorus in the aggregate is added to PO ₄ -P of crystallization treated water and included in total phosphorus (hereinafter referred to as TP). Furthermore, when suspended matter (hereinafter referred to as SS) and soluble organic phosphorus that are not removed and recovered by the crystallization reaction are present in the water to be treated, these SS and organic phosphorus are added to TP. Will be included.
Wastewater subject to the regulation of TP concentration must satisfy, for example, a wastewater standard of 1 mg / L or less in TP. However, conventionally, it has been difficult to stably reduce TP in treated water to 1 mg / L or less for the reasons described above.

  As a result of intensive research, the inventors have found the following facts. That is, when the alkali agent or calcium agent is added in the fluidized bed of the seed crystal, the alkali agent or calcium agent is not sufficiently mixed and stirred, and the alkalinity (pH) degree or calcium concentration is locally increased. From this, it was found that there is a limit to the suppression of aggregates. Thereafter, as a result of further intensive studies, the inventors have completed a reaction crystallization treatment method capable of reducing the generation of aggregates to 0.2 mg-P / L. As a result, the TP of the treated water can be stably reduced to 1 mg / L or less.

This invention is to rapidly and uniformly stirred and mixed in the circulating water, which is part of the treated water agents, achieving uniform drug concentrations in the fluidized bed, it is possible to suppress the occurrence of aggregates reaction An object of the present invention is to provide a crystallization treatment apparatus .

The invention according to claim 1 is a reaction tank for reacting a target component in the water to be treated , a partition partitioning the internal space of the reaction tank into an upper part and a lower part, a pressure chamber provided in a lower part of the internal space, A fluidized bed provided in an upper portion of the internal space, in which seed crystals exist, treated water supply means for supplying the treated water to the fluidized bed through the pressure chamber, and the fluidized by the treated water supply means A part of treated water obtained from the upper part of the fluidized bed is obtained by bringing the target component in the water to be treated supplied to the bed into contact with the seed crystal and crystallizing the target component on the surface of the seed crystal. The circulating water supply means for supplying circulating water to the pressure chamber through the circulating water supply channel, the pressure chamber and the fluidized bed are in communication with each other, and are stored in the pressure chamber. Distribute circulating water and treated water to the fluidized bed A plurality of distributors, and a chemical supply means for supplying a chemical used for the crystallization reaction to a region where turbulent flow is generated in the circulating water in the circulating water supply flow path, and the pressure chamber includes: A circulating water pressure chamber to which circulating water is supplied, and a pressure chamber for water to be treated which is disposed below the circulating water pressure chamber and to which treated water is supplied, The lower end portion communicates with the circulating water pressure chamber and is erected in the reaction tank, and the upper end is located above the fluidized bed of the reaction tank and is disposed in a region where treated water is stored. The cylinder is formed integrally with the upper end portion of the inner cylinder and has a diameter-increased portion that gradually increases in diameter toward the opening at the upper end, and an impeller is accommodated below the diameter-expanded portion in the inner cylinder. The chemical solution supply means has a tip arranged directly above the impeller in the inner cylinder. Is a reactive crystallization apparatus having a chemical liquid supply pipe being.

According to the first aspect of the present invention, since the medicine is added by the medicine supply means to the region where the turbulent flow is generated in the circulating water in the circulating water supply channel, immediately after the medicine is added, the medicine rapidly and uniformly in the circulating water. It is mixed in. Thereby, compared with the case where a chemical | medical agent is added to the area | region where the water flow in the fluidized bed was stabilized conventionally, the raise of the local chemical | medical agent density | concentration in a fluidized bed can be suppressed, and the chemical | medical agent density | concentration can be made uniform. As a result, the generation of aggregates is suppressed.

  As a reaction tank, what has corrosion resistance with respect to the to-be-processed water processed and the chemical | medical agent added to this is preferable. The size of the reaction vessel is not limited. Further, the shape may be a cylindrical shape, or may be a square tube shape of, for example, a quadrangle or more in plan view.
  The magnitude | size and shape of a partition are suitably changed according to the magnitude | size and shape of a reaction tank. The number of partition walls may be one or more. A through hole is formed in the partition wall so that the upper part and the lower part of the reaction tank partitioned by the partition wall can communicate with each other.

  The pressure chamber is a room partitioned in the reaction tank by a partition wall so that treated water, circulating water and the like are evenly blown out to the fluidized bed through a plurality of distributors (blowers).
  The size, shape, formation position, etc. of the pressure chamber formed in the reaction tank are not limited. For example, there may be only one pressure chamber or a plurality of pressure chambers. Among these, when dividing into multiple, you may divide | segment into the height direction of a reaction tank, and may divide | segment into the radial direction (plane direction) of a reaction tank. The number of divisions of the pressure chamber is arbitrary.
  Circulating water or treated water may be stored (supplied) in the pressure chamber. Moreover, both circulating water and to-be-processed water may be sufficient. When the pressure chamber is divided into a plurality of parts as described above, for example, one pressure chamber can be dedicated to circulating water and another pressure chamber can be dedicated to treated water. In that case, since the circulating water is mainly water in the fluidized bed, it is preferable to increase the number of distributors dedicated to circulating water rather than the number of distributors dedicated to treated water.

  The treated water supply means may supply the treated water directly to the fluidized bed or indirectly supply the treated water to the fluidized bed by supplying the treated water to the pressure chamber.
  The treated water supply means includes, for example, a treated water supply tank, a treated water supply path used when the treated water stored in the treated water supply tank is supplied to the pressure chamber, and the treated water. The thing provided with the supply pump of the to-be-processed water in the supply path is employable.
  The circulating water supply means is not limited as long as it has a structure capable of supplying a part of the treated water obtained by the crystallization reaction in the fluidized bed as circulating water to the pressure chamber from the circulating water supply channel. For example, the circulating water supply channel may be provided with a supply pump.

  The material of the distributor is preferably one that has corrosion resistance against water to be treated, chemicals, and the like that come into contact therewith.
  The structure of the distributor is not limited. For example, a lower nozzle umbrella plate disposed above the insertion hole formed in the partition wall, and an upper nozzle umbrella plate erected on the upper surface of each lower nozzle umbrella plate via a plurality of columns, respectively. What you have can be used. This distributor can be used, for example, as a composite supply unit having a double-pipe structure in which a pipe for supplying treated water to a fluidized bed and a pipe for supplying circulating water to a fluidized bed are arranged on a coaxial line.
  The number of distributors used may be two or three or more, and can be appropriately changed according to the floor area of the reaction vessel.
  As the chemical supply means, for example, a chemical solution supply tank in which a chemical solution in which the drug is dissolved in water, a pump in which the chemical solution in the chemical solution supply tank is pumped through the chemical solution supply path, and the like can be adopted. In addition, it is possible to employ a medicine supply tank storing a solid (lump, granule, powder) medicine and a pump in which the solid medicine in the medicine supply tank is pumped through the medicine supply path.

This invention introduces water to be treated into a fluidized bed in which seed crystals are present, and contacts the water to be treated and seed crystals in the fluidized bed, thereby compounding the target component in the water to be treated on the surface of the seed crystals. In the reaction crystallization treatment method, a part of the treated water as circulating water and a chemical used for the crystallization reaction are introduced into the fluidized bed. , of the circulating water supply flow path of the circulating water, as the reactive crystallization process method swirling flow in the region and the circulating water turbulence is generated in the circulating water to be added to at least one region for generating Good.

In this way, since the drug is added to at least one of the circulating water supply flow path and the swirl flow region, the drug circulates rapidly and uniformly immediately after the addition. Mixed in water. Thereby, compared with the case where a chemical | medical agent is added to the area | region where the water flow in a fluidized bed was stabilized conventionally, the increase in the local chemical | medical agent density | concentration in a fluidized bed can be suppressed, and the chemical | medical agent density | concentration can be made uniform. As a result, the generation of aggregates is suppressed.

As the circulating water supply channel, a circulating water channel including a circulation pipe disposed inside the fluidized bed can be employed. Moreover, you may employ | adopt the flow path of the circulating water containing the circulation pipe arrange | positioned outside the fluidized bed.
Of the circulating water supply channel, the region where the turbulent flow is generated in the circulating water may be , for example, a stirring region in which a stirring device is disposed in the middle of the circulating water supply channel. Specifically, in the circulating water supply flow path, the arrangement part of the stirring blade for circulating the circulating water, the vicinity of the upstream part of the stirring blade (hereinafter, immediately before), or the vicinity of the downstream part of the stirring blade (hereinafter, immediately after). ). In addition, it is the arrangement | positioning part of the pressure feed pump which circulates circulating water, or just before or just after that. In the circulating water supply channel, for example, a communication region between a pressure chamber in which a distributor is arranged and a fluidized bed may be used. Specifically, in the circulating water supply flow path, it is an arrangement portion of the distributor, or immediately before (pressure chamber) or immediately after (fluidized bed). Furthermore, it may be a narrow orifice forming portion provided in the circulating water supply flow path, immediately before, or immediately after. Then, in the circulating water supply flow path, for example, a portion where the rapid drug mixing tank is disposed (within the rapid drug mixing tank), immediately before, or immediately after that. Any one of these may be used, or two or more of these may be used.
Further, the region where the swirling flow is generated in the circulating water in the circulating water supply flow path is , for example, the arrangement portion of the line mixer arranged in the middle of the circulating water supply flow path, immediately before or immediately thereafter.

The type of the target component (exclusion target component) is not limited. For example, phosphorus (phosphate phosphorus), fluorine, boron, ammonia, cadmium, chromium (III), zinc, copper, and other heavy metals can be employed. That is, the present invention is effective for removing heavy metal sulfides, carbonates, hydroxides and the like in addition to the removal of phosphate phosphorus in waste water. Among the recovered target components, for example, phosphorus, boron, and ammonia are used for fertilizers. In addition, harmful components such as cadmium, chromium (III), and zinc are taken out as high-purity solids and reused as metal resources.
The kind of to-be-processed water is not limited. For example, when the target component is phosphorus, secondary treated water for sewage treatment, return water in sewage sludge treatment process, and industrial wastewater can be employed. Further, when the target component is fluorine, for example, industrial waste water can be employed. When the target component is boron, for example, industrial wastewater can be employed. When the target component is ammonia, for example, anaerobic digestion and desorption liquid such as industrial wastewater, sewage sludge, and livestock manure can be employed.

  The seed crystal is not limited. When the target component is phosphorus, for example, calcium silicate hydrate, calcium phosphate, phosphate ore, silica sand, bone charcoal, calcium sulfate, calcium carbonate, calcium carbonate magnesium and the like can be employed. When the target component is fluorine, for example, calcium carbonate, calcium fluoride (fluorite), calcium silicate hydrate, or the like can be employed. When the target component is boron, cadmium, chromium (III), zinc and copper, for example, calcium silicate hydrate can be employed.

The kind of chemical | medical solution is not limited. For example, calcium hydroxide (slaked lime (Ca (OH) ₂ )), calcium chloride, sodium hydroxide (caustic soda (NaOH)), magnesium hydroxide, etc. can be used as the chemical solution when the target component is phosphorus. . Moreover, as a chemical | medical solution in case a target component is a fluorine, calcium hydroxide, calcium chloride, sodium hydroxide etc. are employable, for example. As the chemical solution when the target component is boron, cadmium, chromium (III), zinc and copper, for example, calcium hydroxide, sodium hydroxide and the like can be employed. The amount of the chemical solution added is not limited.
The treated water is obtained, for example, as overflow water from the upper part of the reaction tank, and neutralized by aeration, acid addition or the like as necessary.

Moreover, this invention is good also as the reaction crystallization processing method in which the said to-be-processed water is introduce | transduced into a fluidized bed by the flow path different from the treated water to which the said chemical | medical agent was added .

According to this, since the treated water is introduced into the fluidized bed through a flow path different from the treated water to which the chemical is added, the treated water and the treated water containing the chemical come into contact before reaching the fluidized bed. In addition, there is no risk of aggregation.

Further, the present invention provides a reaction crystal in which the water to be treated is a waste water containing phosphate phosphorus, and the phosphorus content in the waste water is removed and recovered by precipitating a calcium phosphate compound on the surface of the seed crystal. An analysis method may be used.

In this way, phosphate phosphorus (PO ₄ -P) in the water to be treated is precipitated as a calcium phosphate compound on the surface of the seed crystal. As a result, the concentration of PO ₄ -P in the water to be treated has an effect of reducing the coagulation concentration even for wastewater of several tens mg / L to several hundred mg / L, and increases phosphorus removal and recovery rate. Can do. As a result, the apparatus can be downsized.

As the drug, for example, an aqueous solution or suspension of calcium hydroxide, or an aqueous solution of sodium hydroxide can be employed.
When the calcium concentration in the water to be treated is insufficient, an aqueous solution of calcium chloride (CaCl ₂ ) or the like can be added to the water to be treated as necessary. The place where calcium chloride is added may be, for example, in a pipe immediately before or immediately after a pressure-feed pump that introduces the water to be treated into the reaction tank, or in a liquid storage tank that temporarily stores the water to be treated.

Further, when the phosphate phosphorus concentration (PO ₄ -P concentration) in the water to be treated is about 100 mg / L or more and the pH is 7.0 or more, pH control with calcium hydroxide or sodium hydroxide is not performed. For example, only calcium chloride (calcium agent) can be added as a chemical agent immediately before the arrangement portion of the impeller (impeller) arranged in the middle of the circulating water supply flow path to remove and recover phosphorus. The relationship between the PO ₄ -P concentration and the calcium concentration using pH as a parameter is shown in the graph of FIG. As is apparent from this graph, the higher the pH, the lower the amount of calcium agent, and the target value (drainage standard value) of 1 mg / L can be reached.
As the seed crystal, one or more of calcium silicate hydrate, calcium phosphate, calcium carbonate and the like are used. A preferred seed crystal is mainly composed of calcium silicate hydrate.

The kind of to-be-processed water containing a phosphorus component is not limited. For example, sewage treated water, return water in the sewage sludge treatment process, industrial wastewater, and the like can be mentioned. When the pressure chamber for to-be-treated water and the pressure chamber for circulating water are partitioned in the reaction tank, the arrangement of both chambers is not limited. For example, both pressure chambers may be arranged vertically (vertical direction), or left and right (horizontal direction). In addition, you may arrange | position both chambers in a center part and an outer peripheral part.
The number of air outlets formed may be one or two or more. As a blower outlet, the distributor which distributes the to-be-processed water of the pressurized chamber for to-be-processed water and the circulating water of the pressurized chamber for circulating water to a some flow, for example is employable.
The outlet is preferably formed separately in the pressure chamber for water to be treated and the pressure chamber for circulating water. However, since the time for the treated water and the circulating water to pass through the outlet is short, the same outlet may be used.

Furthermore, in the present invention, the drug is one or more selected from the group consisting of a calcium compound containing calcium chloride and a hydroxide containing calcium hydroxide and sodium hydroxide, and The chemical may be added to the circulating water as an aqueous solution or suspension, or may be a reaction crystallization treatment method that is added to the circulating water as a solid .

The drug may be a calcium compound or a hydroxide. Moreover, what combined 2 or more types of these may be used. Examples of calcium compounds include calcium sulfate, calcium sulfate, and calcium hydroxide. Examples of the hydroxide include calcium hydroxide and sodium hydroxide, as well as potassium hydroxide and magnesium hydroxide.
As the solid drug, for example, powder, flakes, and granules can be used. In addition, as the drug outside the solid, a liquid prepared by adjusting an aqueous solution or suspension in advance can be employed.

  Of the drugs, calcium hydroxide has the effects of both an alkaline agent and a calcium agent, and is less expensive than sodium hydroxide and calcium chloride. However, the solubility of calcium hydroxide is as small as about 0.16%. Therefore, when the calcium hydroxide aqueous solution is used for pH adjustment, the storage tank for the calcium hydroxide aqueous solution becomes large or the amount of water used increases. Thereby, the method of using calcium hydroxide as a suspension containing more than solubility, for example, about 5% is conceivable. However, if the concentration of the suspension is too high, a part of the calcium hydroxide reaches the fluidized bed without being dissolved, so that the calcium hydroxide is wasted more than necessary. Moreover, this is not preferable because it causes agglomerates and further increases the SS concentration of the treated water. In addition, in order to produce an alkaline agent aqueous solution or suspension, reaction crystallization-treated water can be used when clean water is not available and when it is desired to suppress the amount of water used. However, since aggregates are generated by this, it is preferable that the amount of treated water used is small.

In the present invention, the seed crystal is one or more selected from the group consisting of calcium silicate hydrate, calcium phosphate, phosphate rock, silica sand, bone charcoal, calcium sulfate, calcium carbonate, and calcium magnesium carbonate. It may be a reaction crystallization treatment method .
The seed crystal may be calcium silicate hydrate, calcium phosphate, or calcium carbonate. Further, it may be phosphorus ore, silica sand, bone charcoal, calcium sulfate, calcium carbonate, or calcium magnesium carbonate. Further, a combination of two or more of these may be used.

Further, according to the present invention, the region where the turbulent flow is generated in the circulating water of the circulating water supply channel is an arrangement portion of the stirring blades arranged in the middle of the circulating water supply channel, the vicinity thereof upstream or the vicinity thereof The pump pump arranged in the middle of the circulating water supply flow path, the vicinity of the upstream or the vicinity thereof, or the cross-sectional area of the flow path formed in the middle of the circulating water supply flow path is smaller than the other parts. Arrangement of the rapid drug mixing tank that rapidly mixes the drug and the entire circulating water in the rapid drug mixing tank, which is disposed in the vicinity of the upstream portion or the downstream thereof, or in the middle of the circulating water supply channel The region where the swirling flow is generated in the circulating water of the circulating water supply flow path in the vicinity of the portion or in the vicinity of the upstream or the downstream thereof is the arrangement part of the line mixer arranged in the middle of the circulating water supply flow path or in the vicinity of the upstream Properly it may be a reactive crystallization process method is its downstream neighbors.

The arrangement position of the stirring blades and the pressure pump in the circulating water supply flow path, the arrangement position of the portion where the flow path cross-sectional area is reduced, the arrangement position of the rapid drug mixing tank, or the arrangement position of the line mixer are arbitrary.
Examples of the portion where the cross-sectional area of the flow path is smaller than other portions include, for example, a pressure chamber formed in the lower part of the reaction vessel, and a pressure chamber and a fluidized bed disposed immediately above the reaction chamber. The distributor etc. which were provided in the wall board (partition wall) which separates are mentioned. In addition, the orifice part provided in the middle of the circulating water supply flow path may be sufficient.
As a chemical | medical agent rapid mixing tank, the thing provided with the stirrer which stirs rapidly the whole circulating water and chemical | medical agent in a tank, for example can be employ | adopted. The rapidly mixed drug may be solid or liquid.
The line mixer generates a swirling flow in the liquid in the internal flow path and stirs and mixes the liquid. As a specific configuration, for example, a structure in which a large number of stirring protrusions are arranged at a predetermined pitch in the channel length direction on the inner wall of the channel can be adopted.

Furthermore, the present invention is provided in a reaction tank having a cylindrical shape or a rectangular tube shape and having at least a lower portion gradually taper downward and reacting a target component in the water to be treated, and an internal space of the reaction tank. A fluidized bed in which seed crystals are present, a treated water supply means for supplying the treated water to a lower portion of the internal space, and a treated material supplied by the treated water supply means in the fluidized bed. A part of the treated water obtained from the upper part of the fluidized bed by bringing the target component in water into contact with the seed crystal and crystallizing the target component on the surface of the seed crystal is passed through a circulating water supply channel. Circulating water jetting means for jetting as circulating water from a position below the supply position of the water to be treated in the internal space toward the bottom wall of the reaction tank, and a chemical used for the crystallization reaction, Turbulence occurs in the circulating water in the flow path May be reactive crystallization processing apparatus and a drug supply means for supplying at least one region of the regions and swirl flow in said circulating water occurs that.

In this way, when circulating water is ejected from the circulating water supply channel toward the bottom wall of the reaction tank using the circulating water ejection means, the circulating water is reflected by the bottom wall and flows upward into the reaction tank. Will occur. At this time, the to-be-treated water supplied into the reaction tank by the to-be-treated water supply means rises on this upward flow, and a fluidized bed having a predetermined height is formed.
On the other hand, since the medicine is added by the medicine supply means in a region where turbulent flow occurs in the circulating water in the circulating water supply flow path, immediately after the medicine is added, the medicine is rapidly and uniformly mixed into the circulating water. Thereby, compared with the case where a chemical | medical agent is added to the area | region where the water flow in the fluidized bed was stabilized conventionally, the raise of the local chemical | medical agent density | concentration in a fluidized bed can be suppressed, and the chemical | medical agent density | concentration can be made uniform. As a result, the generation of aggregates is suppressed.

The reaction layer may be cylindrical or rectangular.
The tapered portion having the downward conical shape or the pyramid shape of the reaction tank may be, for example, only the lower part of the reaction tank or the entire reaction tank.
As for the reaction tank used here, internal space is not divided by the partition. Therefore, it is possible to form a fluidized bed over substantially the entire reaction tank.
The circulating water jetting means may have a structure in which a part of the treated water obtained by the crystallization reaction in the fluidized bed is used as circulating water and can be jetted from the circulating water supply channel toward the bottom wall of the reaction tank. There is no limitation. For example, a circulating water supply channel may be provided with a pump or the like. The speed of the circulating water ejected from the circulating water supply channel is, for example, 0.1 to 1 m / second.

Furthermore, according to the present invention, the region where the turbulent flow is generated in the circulating water in the circulating water supply flow path is a portion where the stirring blades are disposed in the middle of the circulating water supply flow path, in the vicinity of the upstream or in the vicinity of the downstream Or the portion of the pumping pump arranged in the middle of the circulating water supply flow path, the vicinity of the upstream or the vicinity thereof, or the cross-sectional area of the flow path formed in the middle of the circulating water supply flow path from other parts. A portion of the rapid drug mixing tank which is disposed in the small part or in the vicinity of the upstream or the downstream thereof or in the middle of the circulating water supply flow path and rapidly mixes the drug and the entire circulating water in the rapid drug mixing tank. The region where the swirling flow is generated in the circulating water of the circulating water supply flow path in the vicinity of the arrangement portion or in the vicinity of the upstream or downstream thereof is the arrangement portion of the line mixer arranged in the middle of the circulating water supply flow path or above it. Near or may be reactive crystallization apparatus is a downstream vicinity.

Further, according to the present invention, a stirring blade or a pressure feed pump is provided in the middle of the circulating water supply flow path, and the arrangement portion of the stirring blade or the pressure feed pump in the circulating water supply flow path, in the vicinity of the upstream or downstream thereof. As a means for generating a turbulent flow or a swirling flow in the circulating water in the circulating water supply flow path, a reaction crystallization treatment apparatus in which at least one of a valve, an orifice, and a line mixer is disposed may be used.
The means for generating turbulent flow or swirling flow in the circulating water in the circulating water supply channel may be a valve, an orifice, or a line mixer. Alternatively, a combination of two or more of these may be used.

According to the reaction crystallization treatment apparatus of claim 1, a chemical is added to a region where turbulent flow is generated in the circulating water in the circulating water supply flow path so that the chemical is rapidly and uniformly mixed into the circulating water. Therefore, the local concentration of the drug in the fluidized bed is prevented from increasing. As a result, the drug concentration can be made uniform and the generation of aggregates can be suppressed.

  Embodiments of the present invention will be described below with reference to the drawings.

  In FIG. 1, reference numeral 10 denotes a crystallization dephosphorization apparatus (reaction crystallization treatment apparatus) according to Example 1 of the present invention. This crystallization dephosphorization apparatus 10 is a reaction for reacting phosphorus as a target component in the water to be treated. A tank 11, a partition wall 51 that divides the internal space of the reaction tank 11 into an upper part and a lower part, a pressure chamber 13 provided in the lower part of the internal space, and a fluidized bed 14 provided in the upper part of the internal space and containing seed crystals. A treated water supply tank (treated water supply means) 15 for supplying treated water to the pressure chamber 13, and phosphorus and seed crystals supplied to the fluidized bed 14 by the treated water supply tank 15 are brought into contact with each other. Circulating water supply means 16 for supplying a part of the treated water obtained from the upper part of the fluidized bed 14 by crystallizing phosphorus on the surface of the seed crystal through the circulating water supply channel 21 to the pressure chamber 13 as circulating water. In a state where the pressure chamber 13 and the fluidized bed 14 are communicated with each other. A plurality of distributors 12 that distribute at least one of circulating water and treated water stored in the pressure chamber 13 to the fluidized bed 14 and a slaked lime aqueous solution (water) used for the crystallization reaction. And a slaked lime aqueous solution supply tank (drug supply means) 17 for storing calcium oxide drug).

The reaction tank 11 is a straight cylinder type cylindrical tank (or a rectangular tube type tank) having a uniform cross-sectional area over the entire length in the length direction. The pressure chamber 13 formed in the lower part of the reaction tank 11 includes a lower pressure chamber for water to be treated 19 to which water to be treated is supplied and a pressure chamber for circulating water to the upper side to which circulating water is supplied. It is partitioned by a partition plate 52.
An annular drainage channel (not shown) through which treated water after dephosphorization is discharged is formed on the outer periphery of the upper edge of the reaction tank 11, and the drainage pipe is connected to a part of the drainage channel so that the treated water is exposed to the outside. It is configured to discharge.

  At the center of the reaction tank 11, a long inner cylinder (circulation water supply flow path) 21 whose lower end communicates with the center of the circulating water pressure chamber 20 has its axis aligned with the axis of the reaction tank 11. Standing up. The upper end of the inner cylinder 21 is disposed above the fluidized bed 14 of the reaction tank 11 and in a region where treated water is stored. The upper end portion of the inner cylinder 21 is integrally formed with an enlarged diameter portion 21a that gradually increases in diameter toward the opening at the upper end.

  On the central part of the reaction tank 11, a stirring motor 41 for a pump device that draws treated water to the inner cylinder 21 is erected. The output shaft 42 of the stirring motor 41 is long, and the impeller 22 is fixed to the tip (lower end). The impeller 22 is disposed slightly below the enlarged diameter portion 21 a in the inner cylinder 21. Therefore, when the output shaft 42 is rotated by the agitation motor 41, the impeller 22 rotates and a downward water flow is generated in the inner cylinder 21. Thereby, the treated water in the upper part of the reaction tank 11 flows into the circulating water pressure chamber 20 from the enlarged diameter portion 21 a through the inside of the inner cylinder 21.

In addition, a tip of a chemical solution supply pipe 17 a in which the slaked lime aqueous solution supply tank 17 is communicated with the base portion is disposed in a portion immediately above the impeller 22 in the inner cylinder 21 (a region where turbulent flow is generated in the circulating water). An electromagnetic valve and a chemical supply pump (not shown) are disposed in the middle of the chemical supply pipe 17a. Therefore, when the chemical liquid supply pump is operated, the slaked lime aqueous solution in the slaked lime aqueous solution supply tank 17 is injected into the portion directly above the impeller 22 through the chemical liquid supply pipe 17a. Immediately thereafter, the slaked lime aqueous solution and the circulating water are mixed quickly and uniformly by the rotational force of the impeller 22. The inner cylinder 21 and the pump device constitute the circulating water supply means 16.
The treated water supply tank 15 and a part of the peripheral side portion of the treated water pressure chamber 19 are communicated with each other by a treated water supply pipe 15a. The treated water supply pipe 15a is provided with a solenoid valve and a treated water supply pump (not shown). By the operation of the treated water supply pump, treated water containing phosphorus in the treated water supply tank 15 is supplied to the pressure chamber 19 for treated water.

Next, the partition wall 51 of the pressure chamber 13 and the distributors 12 will be described in detail.
The partition wall 51 has a disk shape, and a fitting hole 51a at the lower end of the inner cylinder 21 is formed at the center. Further, six mounting holes 51b of the distributor 12 are formed around the insertion hole 51a at intervals of 60 degrees.
Each distributor 12 is placed on a lower nozzle umbrella plate 12a disposed above the corresponding insertion hole 51b and a plurality of support columns (spacers) on each lower nozzle umbrella plate 12a. The upper nozzle umbrella plate 12b.

  Among these, each lower nozzle umbrella board 12a ... is being fixed to the opening part of the upper side of the blowing nozzle 55 ... standingly arranged by the opposing part with each mounting hole 51b ... among the upper walls 52. Each blowing nozzle 55... Has a lower opening communicating with the pressure chamber 19 for water to be treated. Therefore, the treated water supplied from the treated water supply tank 15 to the treated water pressure chamber 19 is supplied from the blow nozzles 55 to the corresponding lower nozzle umbrella plate 12a and upper nozzle umbrella plate 12a. Each is ejected to the fluidized bed 14 through a gap with 12b. Circulating water that has flowed into the circulating water pressure chamber 20 from the inner cylinder 21 passes through the gaps between the mounting holes 51b and the corresponding blowing nozzles 55 from the lower space of the lower nozzle umbrella plates 12a. Each is ejected to the fluidized bed 14.

In addition, as the distributor 12, a distributor 12A dedicated to the water to be treated communicated with the pressure chamber 19 for the water to be treated, and a circulating water outlet from the outlet of the water to be treated of the distributor 12A to form the fluidized bed 14. You may employ | adopt what has the distributor 12B only for circulating water arrange | positioned low and connected with the pressure chamber 20 for circulating water (FIG. 3). Thereby, compared with the distributor 12B, the number of the distributor 12A can be reduced, and the flow rate of the circulating water to the fluidized bed 14 can be increased.
Alternatively, the pressure chamber 19 for treated water may be omitted, and the treated water may be directly introduced from the treated water supply tank 15 through the treated water supply pipe 15a to the bottom of the fluidized bed 14 (FIG. 4). Thereby, the pressure chamber of the reaction chamber 11 becomes one. In this case, the water to be treated may be introduced from the side of the fluidized bed 14 through the treated water supply pipe 15a or may be introduced from the upper part of the fluidized bed 14.

The slaked lime aqueous solution supply tank 17 is installed outside the reaction tank 11. Its internal capacity is, for example, about 0.5 to ⁵ m ³ . Or it is good also as a grade which can store the slaked lime aqueous solution or suspension used for processing for seven days. In the slaked lime aqueous solution supply tank 17, the supply of the slaked lime aqueous solution is automatically performed from the slaked lime aqueous solution supply tank using a supply pump (not shown) based on the detection signal of the liquid level sensor provided in the slaked lime aqueous solution supply tank 17. Or based on the detection signal of the pH sensor provided in the slaked lime aqueous solution supply tank 17, slaked lime powder is supplied into the slaked lime supply tank through a feeder from a slaked lime supply hopper (not shown), and the liquid level provided in the slaked lime supply tank 17. Tap water or treated water is introduced based on the detection signal of the sensor, and is stirred and mixed by a stirrer (not shown) to produce a slaked lime aqueous solution having a predetermined pH.
The reaction tank 11 is provided with a pH sensor 100 that detects the pH of the treated water. The pH sensor 100 is connected to the input side of the pH control device. The pH of the treated water is detected by the pH sensor 100, and based on the obtained detection data, a command is supplied from the pH controller to the chemical solution supply pump to supply a predetermined amount of slaked lime aqueous solution from the slaked lime aqueous solution supply tank 17 to the inner cylinder 21. Is issued.

Next, a reaction crystallization treatment method for phosphorus components in wastewater by the crystallization dephosphorization apparatus 10 according to the first embodiment will be described.
As shown in FIG. 1, an inner cylinder 21 is flowing down by an inverter attached to the chemical solution supply pump so that the signal of the pH sensor 100 installed in the treated water is received and the treated water has a predetermined pH. The amount of slaked lime aqueous solution added to the circulating water is controlled. For example, when the TP (≈PO4-P) concentration is about 1-3 mg / L of sewage secondary treated water, TP <1 mg / L or less, the control target pH is about 9.8.
The circulation amount of the circulating water is adjusted by an inverter attached to the stirring motor 41 so that the expansion height of the fluidized bed 14 becomes a predetermined height. Circulating water is ejected as an upward flow from the inner cylinder 21 through the circulating water pressure chamber 20 and the distributors 12 to the fluidized bed 14. Further, the amount of inflow of the treated water is adjusted by a treated water supply pump with an inverter and introduced into the treated water pressure chamber 19. Thereafter, the water to be treated is jetted to the fluidized bed 14 as an upward flow through the blowout nozzles 55.

The upward flow rate of the water to be treated is appropriately changed according to the conditions (density, particle size) of the seed crystal used, the viscosity of water, and the like. For example, if the seed crystal is calcium silicate hydrate (particle size: 0.5 to 1.0 mm or about 1.0 to 1.7 mm), the upward flow rate of circulating water is preferably 0.5 to 2 m / min. Is 0.8 to 1.5 m / min. Thereby, the expansion rate of the seed crystal in the fluidized bed is preferably about 140 to 200%. If the expansion rate is less than 140%, it is difficult to obtain a stable fluidized bed, and if it exceeds 200%, the circulating flow rate of circulating water increases, the power consumption of the circulating water pump 50 increases, and the density of seed crystals in the fluidized bed increases. This is disadvantageous for the crystallization reaction.
The circulation flow rate of the circulating water is determined by the floor area of the reaction tank 11 x the upward flow velocity, and varies depending on the shape of the reaction tank. Further, the circulating water dilutes the water to be treated, thereby suppressing the aggregation of PO ₄ -P and increasing the treatment speed. Thus, it is preferable to use the reaction tank 11 having a shape in which the flow rate ratio of circulating water / treated water is about 10.

In the fluidized bed 14, a predetermined amount of slaked lime added as an aqueous solution and the water to be treated are introduced into the main circulating water. Therefore, in the fluidized bed 14, a crystallization reaction for precipitating PO ₄ -P contained in the water to be treated as hydroxyapatite is performed. The reaction formula is shown in formula (1) in the column of background art. By the way, the injection position of the slaked lime aqueous solution into the treated water flowing in the inner cylinder 21 is a portion immediately above the impeller 22. Therefore, immediately after that, the slaked lime aqueous solution is rapidly and uniformly stirred and mixed by the impeller 22 with the circulating water. As a result, compared to the conventional case where the aqueous slaked lime solution is added to a region where the water flow in the fluidized bed is stable, the local increase in the concentration of slaked lime in the fluidized bed 14 is suppressed, and Uniformity of slaked lime concentration can be achieved. As a result, the generation of aggregates is suppressed.

The circulating water supplied to the circulating water pressure chamber 20 through the inner cylinder 21 flows through the lower space of each lower nozzle umbrella plate 12a ... from the gap between each mounting hole 51b ... and the corresponding blowing nozzle 55 .... It is ejected to the floor 14 as an upward flow. At this time, the water to be treated is injected into the fluidized bed 14 through a different route (separate flow path) from the slaked lime aqueous solution and the circulating water. Thereby, compared with the case where the to-be-processed water and circulating water are mixed previously like this and this mixed liquid is supplied to the fluidized bed 14, generation | occurrence | production of the aggregate can be suppressed. This is because there is a high possibility that aggregation of PO ₄ -P occurs at the time when the circulating water and the water to be treated containing phosphorus come into contact, and this can be prevented. The treated water is discharged to the outside through a drain pipe from a drain channel provided in the upper part of the reaction tank 11. The discharged treated water is neutralized by aeration, acid addition or the like as necessary.

In the case where the calcium concentration in the water to be treated is insufficient, it may be added such as an aqueous solution of calcium chloride (CaCl ₂₎ as required. The place to which calcium chloride is added may be in a portion of the treated water supply pipe 15a immediately before or after the treated water supply pump or in a storage tank that receives the treated water. When the PO ₄ -P concentration in the water to be treated is about 100 mg / L or more and the pH is 7.0 or more, pH control with slaked lime is not performed, and only calcium chloride is added to the portion immediately above the impeller 22 to add phosphorus. It can also be removed and recovered.
In addition, according to this method, even for wastewater having a PO ₄ -P concentration of several tens mg / L to several hundred mg / L, it has an effect of reducing the aggregation concentration, and phosphorus removal in the reaction crystallization method, The recovery rate can be increased. Thereby, the reaction crystallization treatment apparatus can be made compact.

Next, a reactive crystallization treatment method and apparatus according to Reference Example 1 of the present invention will be described with reference to FIG.
As shown in FIG. 2, in the crystallization dephosphorization apparatus 10A according to Reference Example 1 of the present invention, the circulating water supply means 16 of Example 1 is removed. Further, an annular drainage channel 11 a is provided in the upper part of the reaction tank 11 along the peripheral wall, and the drainage channel 11 a and the circulating water pressure chamber 20 are connected to a circulating water supply flow pipe (circulation) piped outside the reaction tank 11. A water supply channel 21A communicates. A circulating water pressure feed pump 50 is provided downstream of the circulating water supply flow pipe 21A. Further, the distal end portion of the chemical solution supply pipe 17a in which the slaked lime aqueous solution supply tank 17 and the base portion are communicated with each other is disposed in the vicinity of the downstream portion of the circulating water supply flow pipe 21A, specifically, immediately before the circulating water pressure feed pump 50. ing.

In the reaction crystallization treatment method by the crystallization dephosphorization apparatus 10A, the circulating water pressure pump 50 is operated to supply the circulating water in the drainage channel 11a to the circulating water pressure chamber 20 through the circulating water supply flow pipe 21A. At this time, the slaked lime aqueous solution derived from the slaked lime aqueous solution supply tank 17 is supplied to the portion of the circulating water supply flow pipe 21A immediately before the circulating water pressure feed pump 50 through the chemical liquid supply pipe 17a. Therefore, immediately after that, the slaked lime aqueous solution that has flowed into the circulating water supply flow pipe 21A is rapidly and uniformly stirred and mixed with the circulating water by the stirring force of the circulating water pressure feed pump 50.
Other configurations, operations, and effects are in a range that can be estimated from the first embodiment, and thus the description thereof is omitted.

Next, a reactive crystallization treatment method and apparatus according to Reference Example 2 of the present invention will be described with reference to FIG.
As shown in FIG. 5, in the crystallization dephosphorization apparatus 10 </ b> B to which the reaction crystallization treatment method according to Reference Example 2 of the present invention is applied, instead of the slaked lime aqueous solution supply tank 17 of Reference Example 1 , average grains A slaked lime powder supply tank 17A into which powdered slaked lime having a diameter of about 10 μm is introduced, and a circulating water pressure pump 50 is provided upstream of the circulating water supply flow pipe 21A. A branch pipe 21b whose upper end is opened to the atmosphere is vertically communicated with a portion of the circulating water supply flow pipe 21A immediately before the circulating water pressure feed pump 50. In addition, the distal end portion of the medicine supply pipe 17b of the slaked lime powder supply tank 17A communicates with the branch pipe 21b. In the middle of the medicine supply pipe 17b, a powder pump and a solenoid valve (not shown) for supplying medicine are arranged. The slaked lime powder charged into the chemical supply pipe 17b from the slaked lime powder supply tank 17A is dissolved in the circulating water in the circulating water supply flow pipe 21A. As a result, it finally becomes a slaked lime aqueous solution and flows into the circulating water pressure chamber 20.

In the reaction crystallization treatment method by the crystallization dephosphorization apparatus 10B of Reference Example 2 , when the circulating water pressure feed pump 50 is operated, the circulating water in the drainage channel 11a passes through the circulating water supply flow pipe 21A, and the circulating water pressure. Supplied to the chamber 20. At this time, the slaked lime powder derived from the slaked lime powder supply tank 17A is supplied to a portion of the circulating water supply flow pipe 21A immediately before the circulating water pressure feed pump 50 through the chemical supply pipe 17b and the branch pipe 21b. . Therefore, immediately after the slaked lime powder is charged, the slaked lime powder is rapidly and uniformly stirred and mixed with the circulating water by the stirring force of the circulating water pressure pump 50.

Further, the branch pipe 21b is removed in the crystallization dephosphorization apparatus 10B, and the chemical rapid mixing tank 50A is provided in the communicating portion of the circulating water supply flow pipe 21A with the branch pipe 21b, whereby slaked lime powder and circulating water are provided in this tank. May be rapidly stirred and mixed (FIG. 6). The chemical rapid mixing tank 50A is a small tank having a volume that allows circulating water to stay for 10 seconds or more, and a large output stirrer 60 is attached to the small tank. The slaked lime powder charged into the tank and all the circulating water liquid in the tank are rapidly stirred and mixed by the stirrer 60.
Furthermore, in the crystallization dephosphorization apparatus 10B shown in FIG. 5, a line mixer 50B may be provided in a portion between the circulating water supply flow pipe 21A and the circulating water pumping pump 50 between the communicating portion with the branch pipe 21b. Good (Fig. 7). The line mixer 50B is a non-powered cylindrical mixer in which a large number of stirring protrusions are arranged at a predetermined pitch in the flow path length direction on the inner wall of the flow path. When the circulating water to which the slaked lime powder is added passes through the internal flow path of the line mixer 50B, a swirling flow is generated in the flow path, and the circulating water and the slaked lime powder are stirred and mixed.
Other configurations, operations, and effects are in a range that can be inferred from Reference Example 1 , and thus description thereof is omitted.

Next, a reactive crystallization treatment method and apparatus according to Reference Example 3 of the present invention will be described with reference to FIG.
As shown in FIG. 8, in the crystallization dephosphorization apparatus 10C to which the reaction crystallization treatment method according to Reference Example 3 of the present invention is applied, the straight barrel type cylindrical tank or rectangular tube tank of Reference Example 1 is used. Instead of a certain reaction tank 11, a reaction tank 11 </ b> A in which the pressure chamber 13 is excluded and the lower part (bottom part) is gradually tapered downward is adopted. Further, the lower end portion of the circulating water supply flow pipe 21A is arranged at the lower end portion of the reaction tank 11A with the opening direction of the lower end facing downward. And the front-end | tip part of the said to-be-processed water supply pipe | tube 15a is arrange | positioned in the lower part of 11 A of reaction tanks, and a little above the circulating water supply flow pipe | tube 21A.

Therefore, when circulating water is ejected from the circulating water supply flow pipe 21 </ b> A toward the bottom wall of the reaction tank 11 at 1 m / sec or less (here, about 1 m / sec) by the circulating water feed pump 50, An upward flow is generated. The treated water supplied from the treated water supply pipe 15a to the reaction tank 11 rises on this upward flow, and a fluidized bed 14 having a predetermined height is formed.
Other configurations, operations, and effects are substantially the same as those in Reference Example 1, and thus description thereof is omitted.

Next, each crystallization was performed by the reaction crystallization treatment method using the reaction crystallization treatment apparatus 10 of Example 1 and the reaction crystallization treatment method of Conventional Example 1 using the reaction crystallization treatment apparatus 10D shown in FIG. We will actually conduct experiments and report the results of water quality analysis of the treated water obtained by these experiments. First, the reaction crystallization treatment apparatus 10D of Conventional Example 1 will be described.
As shown in FIG. 10, the reaction crystallization treatment apparatus 10 </ b> D of Conventional Example 1 is connected to the slaked lime aqueous solution supply tank 17 via the chemical solution supply pipe 17 a on the upper side of the partition wall 51 and supplies the slaked lime aqueous solution to the fluidized bed 14. The chemical solution supply chamber 56 is provided, and a large number of chemical solution blowing nozzles 57 are erected at a predetermined pitch on the upper wall 56a of the chemical solution supply chamber 56. Distributors 12C are provided at the upper ends of the respective chemical solution blowing nozzles 57.
Therefore, the slaked lime aqueous solution in the slaked lime aqueous solution supply tank 17 flows into the chemical solution supply chamber 56 through the chemical solution supply pipe 17a and is blown out to the fluidized bed 14 through the respective chemical solution blowing nozzles 57. Therefore, in the fluidized bed 14, the slaked lime concentration is increased around each distributor 12C. Other configurations, operations, and effects are the same as those in the first embodiment.

Next, each crystallization experiment by the reaction crystallization treatment method of Example 1 and the reaction crystallization treatment method of Conventional Example 1 will be described.
The used seed crystal is “wrinkle seed” manufactured by Mitsubishi Materials Corporation, particle size: 0.5 to 1.0 mm, main component: calcium silicate hydrate.
The seed crystal filling volume was set to 130 L (liter), the treatment water circulation flow rate was adjusted by an inverter connected to the stirring motor 41, and the seed crystal expansion rate was set to 200%. The treated water flow rate was adjusted using an inverter connected to the treated water supply pump and confirmed with a flow meter. The chemical injection amount was controlled using an inverter connected to a chemical solution supply pump so that the treated water had a predetermined pH by the pH sensor 100 installed on the upper part of the fluidized bed 14.
Biological wastewater was used as water to be treated, and phosphate ions were added and adjusted to a predetermined PO ₄ -P concentration with an aqueous KH ₂ PO ₄ solution. Further, since the calcium concentration of the water to be treated was about 10 mg / L, calcium was added to the water to be treated using a CaCl ₂ aqueous solution and supplied to the reaction tank 11. The calcium concentration of to-be-processed water in Table 1 is an analytical value after adjusting the calcium concentration with a CaCl ₂ aqueous solution. The results are shown in Table 1.
In Table 1, Experiment Nos. 1 to 10 show Test Examples 1 to 10. Moreover, experiment numbers 11-13 show Comparative Examples 1-3.

The space velocity (SV) was obtained by dividing the flow rate per hour of water to be treated by the seed crystal filling volume. The larger this value is, the faster the treatment speed is, and the apparatus can be made compact when the treated water flow rate is the same.
Aggregated phosphorus concentration is {(treated water TP)-(treated water PO ₄ -P)}-{(treated water TP)
- it was determined by (treated water _PO 4 -P)}.
In Experiment No. 2, when the solution after circulating chemical mixing was collected from the pressure chamber, pH = 9.9, T−P = 0.73 mg / L, PO ₄ −P = 0.34 mg / L, It was close to the quality of the treated water. In other experiment numbers 1 and 3 to 10, the TP values of the treated water were all 1 mg / L or less. That is, it has been clarified that the rapid mixing and stirring of the drug does not cause a high pH state and produces an aggregation suppressing effect.

Next, the crystallization experiment and water quality analysis actually performed on the wastewater containing fluorine by each reaction crystallization treatment method of Example 1 and each reaction crystallization treatment method of Conventional Example 1 are reported.
As the seed crystal, fluorite (calcium fluoride) having a purity of 97% and having a particle size adjusted to a particle size of 0.3 to 0.5 mm was used.
The filling volume of the seed crystal was 100 L, the treatment water circulation flow rate was adjusted by an inverter connected to the stirring motor 41, and the seed crystal expansion rate was 150%.
As the water to be treated, simulated waste water using a sodium fluoride reagent and adjusting the fluorine ion concentration to 20 mg / L was used. The treated water flow rate was adjusted by an inverter connected to the treated water supply pump and confirmed with a flow meter.

As a drug, a 20% calcium chloride aqueous solution was employed. The injection amount was controlled by an inverter connected to a drug injection pump. A chemical | medical agent is inject | poured by the proportional control according to the to-be-processed water flow rate.
JIS K 0102 lanthanum-alizarin complexone spectrophotometric method was adopted for the analysis of the fluorine ion concentration. The test results are shown in Table 2. In Table 2, Experiment No. 14 indicates Test Example 11. Experimental number 15 indicates Comparative Example 4.
As is clear from Table 2, in Experiment No. 14, the treated water was not cloudy and the SS (sludge) concentration was low. In contrast, in Experiment No. 15, the treated water became cloudy, SS increased, and the fluorine ion concentration was high. This is presumably because a large amount of fine calcium fluoride particles that did not crystallize on the surface of the seed crystal remained in the treated water.

It is a schematic block diagram of the reaction crystallization processing apparatus which concerns on Example 1 of this invention. It is a schematic block diagram of the reaction crystallization processing apparatus which concerns on the reference example 1 of this invention. It is a schematic block diagram of another reaction crystallization processing apparatus which concerns on the reference example 1 of this invention. It is a schematic block diagram of another reaction crystallization processing apparatus which concerns on the reference example 1 of this invention. It is a schematic block diagram of the reaction crystallization processing apparatus which concerns on the reference example 2 of this invention. It is a principal part schematic block diagram of the reaction crystallization processing apparatus which concerns on the other form of the reference example 2 of this invention. It is a principal part schematic block diagram of the reaction crystallization processing apparatus which concerns on another form of the reference example 2 of this invention. It is a schematic block diagram of the reaction crystallization processing apparatus which concerns on the reference example 3 of this invention. pH is a graph showing the relationship between PO 4 _-P concentration and the calcium concentration was parameters. It is a schematic block diagram of the reaction crystallization processing apparatus based on the conventional means.

10, 10A-10D crystallization dephosphorization apparatus (reaction crystallization treatment apparatus),
11 reaction tank,
12 Distributor,
13 Pressure chamber,
14 fluidized bed,
15 Untreated water supply tank (untreated water supply means),
16 Circulating water supply means,
17 Slaked lime aqueous solution supply tank (medicine supply means),
21 inner cylinder (circulation water supply flow path),
21A Circulating water supply flow pipe (circulating water supply flow path),
22 impeller (stirring blade),
50 pressure pump,
50A drug rapid mixing tank,
50B line mixer,
51 bulkhead,
61 Stir blade.

Claims (1)

A reaction vessel for reacting target components in the water to be treated;
A partition partitioning the internal space of the reaction vessel into an upper part and a lower part;
A pressure chamber provided in a lower portion of the internal space;
A fluidized bed provided in an upper portion of the internal space and containing seed crystals;
To-be-treated water supply means for supplying the to-be-treated water to the fluidized bed through the pressure chamber;
From the upper part of the fluidized bed, the target component in the treated water supplied to the fluidized bed by the treated water supply means is brought into contact with the seed crystal, and the target component is crystallized on the surface of the seed crystal. A circulating water supply means for supplying a part of the treated water to the pressure chamber as circulating water through a circulating water supply channel;
A plurality of distributors provided in the partition wall in a state where the pressure chamber and the fluidized bed are communicated, and distributing circulating water and treated water stored in the pressure chamber to the fluidized bed;
A chemical supply means for supplying a chemical used for the crystallization reaction to a region where turbulent flow is generated in the circulating water in the circulating water supply flow path;
The pressure chamber is composed of a circulating water pressure chamber to which circulating water is supplied, and a treated water pressure chamber that is disposed below the circulating water pressure chamber and to which treated water is supplied,
The circulating water supply flow path has a lower end communicating with the circulating water pressure chamber and standing in the reaction tank, and an upper end above the fluidized bed of the reaction tank and storing treated water. An inner cylinder disposed in the region, and an enlarged diameter portion that is integrally formed with the upper end of the inner cylinder and that gradually increases in diameter toward the opening at the upper end.
An impeller is housed below the enlarged diameter portion in the inner cylinder,
The chemical solution supply means is a reaction crystallization treatment apparatus having a chemical solution supply pipe having a tip disposed immediately above an impeller in the inner cylinder.

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