WO2006035834A1

WO2006035834A1 - Method of treatment with reactional crystallization and apparatus therefor

Info

Publication number: WO2006035834A1
Application number: PCT/JP2005/017881
Authority: WO
Inventors: Katsumi Moriyama; Toshihiro Kojima; Toshihiko Nakamura; Shoroku Kawauchi; Ryuki Watanabe
Original assignee: Mitsubishi Materials Corporation; Hanshin Engineering Co., Ltd.
Priority date: 2004-09-28
Filing date: 2005-09-28
Publication date: 2006-04-06
Also published as: JP2006122896A; JP4892212B2

Abstract

A method of treatment with reactional crystallization which comprises introducing a water to be treated into a fluidized bed in which seed crystals are present, contacting the raw water with the seed crystals in the fluidized bed to cause the target ingredient contained in the raw water to crystallize out as a compound on the surface of the seed crystals and thereby obtain a treated water, and introducing part of the treated water as circulating water and an agent for the crystallization reaction into the fluidized bed, wherein an aqueous slaked lime solution is added to that region in a circulating-water supply passage in which a turbulent flow occurs in the circulating water or a turning flow occurs in the circulating water.

Description

Reaction crystallization treatment method and apparatus

Technical field

[0001] The present invention relates to a reactive crystallization treatment method and apparatus, in particular, sewage or industrial wastewater, in which a target component contained in water to be treated is deposited on the surface of a seed crystal by crystallization to be removed and recovered. TECHNICAL FIELD The present invention relates to a reaction crystallization treatment technique for removing and recovering phosphoric phosphorus from a reaction.

This application is based on Japanese Patent Application No. 2004-282160 filed with the Japan Patent Office on September 28, 2004, and Japanese Patent Application No. 2005-272946 filed with the Japan Patent Office on September 20, 2005. Claim the right and use it here.

Background art

[0002] 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 is recovered and reused as phosphorus resources. In addition, a crystallization dephosphorization method (reaction crystallization treatment method) that is possible is attracting attention. In the crystallization reaction, phosphorus in the water to be treated is precipitated as sparingly soluble hydroxyapatite. Solubility product hydroxy § patterns site is very small (Ksp = 10_ ^56), it is possible to obtain treated water of low phosphorus concentration.

[0003] The basic principle of removal and recovery of phosphate phosphorus (hereinafter referred to as PO-P) in wastewater by this method is

Four

This is to precipitate calcium phosphate (hydroxyapatite; HAp) on the surface of the seed crystal by the reaction shown in the following formula (1). Therefore, the PO-P concentration and power in the target wastewater

4 Necessary amount of calcium ion (calcium agent), hydroxide depending on the concentration of ruthenium ion (Ca ²⁺ ), pH of hydroxide ion (OH_) concentration, PO—P concentration of the target treated water Things

Four

Add ions (alkali agent).

10Ca ²⁺ + 2OH "+ 6PO ³ " → Ca (OH) (PO) (1)

4 10 2 4 6

[0004] Conventionally, for example, Patent Document 1 is known as a crystallization reaction apparatus.

Patent Document 1 describes the pressure chamber force distributor provided in the lower part of the reaction tank.

The liquid mixture of the water to be treated and the water to be treated after crystallization treatment is ejected as an upward flow to form a fluidized bed in which a plurality of seed crystal grains are suspended above the distributor. It is configured as follows. In addition, by supplying a chemical solution (calcium agent or alkaline agent solution) to the fluidized bed, the components to be excluded contained in the water to be treated are 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 of pH control at this time is the PO-P concentration of treated water.

The force varies depending on 4 degrees, etc. It is approximately pH 9.5 to pH 12.

Patent Document 1: JP 2002-301480 A

Disclosure of the invention

Problems to be solved by the invention

However, when removing phosphorus in waste water according to Patent Document 1, all phosphate ions are not deposited on the surface of the seed crystal. That is, some phosphate ions are precipitated in the liquid away from the seed crystal as aggregates of fine calcium phosphate. Aggregates are discharged while floating in the treated water without being trapped on the surface of the seed crystals. Generation of such agglomerates, PO- P concentration of the treatment in water which is a potential precipitation of calcium phosphate compounds, calcium ion concentration and _P H, more water temperature, filling of the seed crystal

Four

It also varies depending on the amount, contact time and reactor type.

[0006] Conventionally proposed crystallization reaction treatment methods use low-concentration phosphorus-containing wastewater (PO—P concentration).

4 degrees is about 1 to 3 mgZL (liter)), but even if the operation control conditions are optimized, the amount of agglomerates generated is limited to about 0.3 to 0.5 mg-PZL. . In other words, the phosphorus in the agglomerates is added to the PO-P of the crystallization water to give total phosphorus (hereinafter referred to as T P).

Four

included. Furthermore, if suspended water (SS) and soluble organic phosphorus that cannot be removed or recovered by the crystallization reaction are present in the treated water, these SS and organic phosphorus are added to the T-P. Will be included.

Wastewater subject to regulation of TP concentration must satisfy the effluent standard of lmgZL or less in TP, for example. However, conventionally, it has been difficult to stably reduce TP in treated water to 1 mg ZL or less for the reasons described above.

It is an object of the present invention to provide a reaction crystallization treatment method and apparatus capable of suppressing the generation of aggregates. Means for solving the problem

[0007] Therefore, the inventors have found the following fact as a result of earnest research. In other words, if an alkali agent or calcium agent is applied in a fluidized bed of seed crystals, mixing and stirring of the alkali agent or calcium agent is not sufficiently performed, and the alkali (pH) degree or calcium concentration is locally increased. Rise. 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-PZL or less. As a result, the TP of treated water can be stably kept below lmgZL.

[0008] In this invention, the drug is rapidly and uniformly stirred and mixed in the circulating water that is a part of the treated water, thereby achieving uniform drug concentration in the fluidized bed and suppressing the generation of aggregates. It is an object of the present invention to provide a reaction crystallization treatment method and an apparatus therefor.

In addition, the present invention provides a PO—P concentration in the water to be treated of several tens mgZL to several hundred mgZL.

Four

It is effective in reducing the concentration of coagulation in water, and it is possible to provide a reaction crystallization treatment method that can increase the removal and recovery rate of phosphorus in the reaction crystallization method, thereby reducing the size of the apparatus. It is aimed.

[0009] In a first aspect of the present invention, water to be treated is introduced into a fluidized bed in which a seed crystal is present, and the water to be treated and the seed crystal are brought into contact with each other in the fluidized bed, whereby the surface of the seed crystal is obtained. The target component in the water to be treated is crystallized as a compound to obtain treated water, and the fluidized bed contains a part of the treated water as circulating water and a chemical used for the crystallization reaction. In the reactive crystallization treatment method to be introduced, the chemical agent is at least one of a region where a turbulent flow is generated in the circulating water and a region where a swirling flow is generated in the circulating water in the circulating water supply channel of the circulating water. It is a reaction crystallization treatment method added to the other.

[0010] According to the first aspect of the present invention, the drug is added to at least one of the region where the turbulent flow is generated in the circulating water and the region where the swirl flow is generated in the circulating water supply channel. Immediately after

The drug is rapidly and uniformly mixed into the circulating water. As a result, compared to the conventional case where the drug is added to the region where the water flow in the fluidized bed is stable, the increase in the concentration of the local drug in the fluidized bed is suppressed, and the drug concentration can be made uniform. . As a result, the generation of aggregates is suppressed. [0011] As the circulating water supply channel, a circulating water channel including a circulation pipe (for example, an inner cylinder) disposed inside the fluidized bed can be employed. Further, a circulating water flow path including a circulating pipe (for example, a circulating water supply pipe) arranged outside the fluidized bed may be employed.

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 vicinity of the arrangement part of the stirring blade for circulating the circulating water or the upstream part of the arrangement part of the stirring blade (hereinafter immediately before) or the vicinity of the downstream part of the arrangement part of the stirring blade (hereinafter referred to as the following) , Immediately after). In addition, it is the location of the pressure pump that circulates the 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 the part where the distributor is arranged, immediately before (pressure chamber), or immediately after (fluidized bed). Furthermore, it may be the portion where the narrow orifice provided in the circulating water supply flow path is formed, or just before or just after that. Then, in the circulating water supply channel, for example, it may be a portion where the rapid drug mixing tank is disposed (in the rapid drug mixing tank), immediately before, or immediately after. 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, an arrangement portion of the line mixer arranged in the middle of the circulating water supply flow path, immediately before or immediately thereafter.

[0012] The type of the target component (exclusion target component) is not limited. For example, phosphorus (phosphate phosphorus), fluorine, boron, ammonia, cadmium, chromium (111), zinc, copper, and other heavy metals can be used. In other words, the present invention is effective for removing heavy metal sulfides, carbonates, hydroxides, and the like in addition to removing phosphate phosphorus in waste water. Among the collected target components, for example, phosphorus, boron and ammonia are used for fertilizers. In addition, harmful components such as cadmium, chromium (111), and zinc are extracted 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 from the sewage sludge treatment process, and industrial wastewater can be used. 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.

[0013] 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. Further, when the target component is fluorine, for example, calcium carbonate, calcium fluoride (fluorite), calcium silicate hydrate, etc. can be employed. When the target component is boron, cadmium, chromium (111), zinc and copper, for example, calcium silicate hydrate can be employed.

[0014] The type of the chemical solution is not limited. For example, when the target ingredient is phosphorus, chemicals include calcium hydroxide (slaked lime (Ca (OH))), salt calcium, sodium hydroxide sodium (caustic soda).

2

(NaOH)), magnesium hydroxide, etc. can be employed. In addition, as a chemical solution when the target component is fluorine, for example, calcium hydroxide, calcium salt, sodium hydroxide and the like can be employed. As the chemical solution when the target component is boron, cadmium, chromium (111), zinc and copper, for example, calcium hydroxide, sodium hydroxide, etc. 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.

[0015] A second aspect of the present invention is the reaction crystallization treatment method according to the first aspect, wherein the treated water is placed in a fluidized bed in a flow path different from the treated water to which the chemical is added. This is a reactive crystallization treatment method to be introduced.

[0016] According to the second aspect of the present invention, since the water to be treated is introduced into the fluidized bed through a flow path different from the treated water to which the chemical has been added, There is no risk of coagulation due to contact with treated water containing chemicals.

[0017] In the third or fourth aspect of the present invention, in the reaction crystallization treatment method of the first or second aspect, the water to be treated is a waste water containing phosphate phosphorus, This is a reaction crystallization treatment method in which a calcium compound is precipitated on the surface of the seed crystal to remove and recover phosphorus in the waste water. [0018] According to the third or fourth aspect of the present invention, the phosphorous phosphorus (PO-P) in the water to be treated is

4 Precipitate as calcium phosphate compound on the seed crystal surface. As a result, the concentration of PO-P in the water to be treated can be reduced even for wastewater of several tens mgZL to several hundred mgZL.

Four

It has an effect, and phosphorus removal and recovery rate can be increased. As a result, the size of the apparatus can be reduced.

[0019] As the chemical, for example, an aqueous solution or suspension of calcium hydroxide or an aqueous solution of sodium hydroxide can be employed.

If the calcium concentration in the water to be treated is insufficient, an aqueous solution of calcium chloride (CaCl 3) or the like can be added to the water to be treated as necessary. Salty calcium

2

The place to add can be, for example, the internal pressure of the pipe immediately before or after the treated water supply pump, or the storage tank where the treated water can be stored easily! /.

[0020] Furthermore, if the phosphate concentration (PO—P concentration) in the treated water is about lOOmgZL or more,

Four

When the pH is 7.0 or higher, pH control is not performed with calcium hydroxide or sodium hydroxide, and only the salt calcium (calcium agent), for example, is used as the drug. It is also possible to remove and recover phosphorus by adding it immediately before the part where the impeller (impeller) placed in the middle is placed. The graph in Fig. 9 shows the relationship between PO 4-P concentration and calcium concentration with pH as a parameter. As is clear from this graph, the higher the pH, the lower the amount of calcium solution, and the target value (drainage standard value) of lmgZL can be reached.

As seed crystals, use one or more of calcium silicate hydrate, calcium phosphate, calcium carbonate, etc. Preferred seed crystals are those containing calcium silicate hydrate as a main component.

[0021] The type of water to be treated containing a phosphorus component is not limited. Examples include sewage treated water, return water in the sewage sludge treatment process, and industrial wastewater. When the pressure chamber for water to be treated 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, both chambers may be arranged at the central portion and the outer peripheral portion.

The number of air outlets may be one, or two or more. As the outlet, for example, the water to be treated in the pressurized chamber for treated water and the circulating water in the pressurized chamber for circulating water are divided into a plurality of flows. A distributor can be employed.

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.

[0022] In the fifth or sixth aspect of the present invention, in the reaction crystallization treatment method of the third or fourth aspect, the agent comprises a calcium compound containing calcium chloride, calcium hydroxide, and calcium hydroxide. 1 or more selected in the group with a hydroxide containing sodium hydroxide and sodium hydroxide, and whether the drug is added to the circulating water as an aqueous solution or suspension The reaction crystallization treatment method is added to the circulating water as a solid.

[0023] The drug may be a calcium compound! /, Or a hydroxide! /. Also, a combination of two or more of these may be used. Examples of calcium compounds include calcium sulfate, calcium sulfate, calcium hydroxide and the like in addition to calcium chloride. Examples of hydroxides 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. Further, as the drug outside the solid, it is possible to adopt a liquid prepared by adjusting the aqueous solution or suspension.

[0024] Among the drugs, calcium hydroxide has the effects of both an alkali agent and a calcium agent, and is less expensive than sodium hydroxide sodium salt and calcium salt calcium salt. However, the solubility of calcium hydroxide is as small as about 0.16%. For this reason, when using a calcium hydroxide aqueous solution for pH adjustment, the storage tank for the aqueous solution of calcium hydroxide and calcium carbonate becomes larger and the amount of water used increases. Thus, a method of using a suspension containing calcium hydroxide or higher in solubility, for example, about 5% is conceivable. However, if the concentration of this suspension is too high, a portion of the calcium hydroxide reaches the fluidized bed in an undissolved state, so that the calcium hydroxide is wasted more than necessary. This is also unfavorable because it causes the generation of aggregates and further increases the SS concentration of the treated water. In addition, since an aqueous alkali solution or suspension is prepared, water for reaction crystallization can be used when clean water is not available or when the amount of water used is to be suppressed. However, this will generate aggregates. Because of this, the amount of treated water used is low! /.

[0025] The seventh, eighth, or ninth aspect of the present invention is the reaction crystallization treatment method according to the third, fourth, or fifth aspect, wherein the seed crystal is calcium silicate hydrate, calcium phosphate. This is a reactive crystallization treatment method that is one or more selected from the group of phosphorus ore, quartz sand, bone charcoal, calcium sulfate, calcium carbonate, and calcium magnesium carbonate.

The seed crystal may be calcium silicate hydrate, calcium phosphate, or carbonated lucium. Further, it may be phosphate 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.

[0026] In a tenth aspect of the present invention, the region where the turbulent flow is generated in the circulating water in the circulating water supply flow path is an arrangement portion of a stirring blade arranged in the middle of the circulating water supply flow path or upstream thereof. Near or near the downstream, the arrangement part of the pumping pump arranged in the middle of the circulating water supply flow path, the vicinity of the upstream or the downstream thereof, or the channel cross-sectional area formed in the middle of the circulating water supply flow path Is disposed in the vicinity of the downstream portion, the upstream portion thereof, or the downstream portion 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 chemical rapid mixing tank or in the vicinity of the upstream or downstream thereof is a line mixer disposed in the middle of the circulating water supply flow path. Placement part of Is the reactive crystallization treatment method according to any one of the first to ninth embodiments, which are in the vicinity of the upstream or the vicinity of the downstream thereof.

[0027] The arrangement position of the stirring blades and the pressure feed pump in the circulating water supply flow path, the arrangement position of the portion where the cross-sectional area of the flow path is small, the arrangement position of the rapid drug mixing tank, or the arrangement position of the line mixer are respectively Is optional.

Examples of the portion where the cross-sectional area of the flow path is smaller than the other portions include, for example, a pressure chamber formed in the lower part of the reaction tank, a pressure chamber and a fluidized bed disposed immediately above the pressure chamber. Distributors provided on the wall plates (partitions) separating the walls. In addition, the orifice part provided in the middle of the circulating water supply flow path.

For example, the drug rapid mixing tank rapidly agitates the entire circulating water in the tank and the drug. The thing provided with the stirrer can be employ | adopted. The rapidly mixed drug may be solid or liquid.

A line mixer generates a swirling flow in a liquid in an 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.

In the reaction crystallization treatment method of the present invention, the chemical used for the crystallization reaction may be added to a high region of the circulating water turbulence intensity in the circulating water supply channel.

[0028] An eleventh aspect of the present invention is provided in 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, and a lower part of the internal space. A pressure chamber, a fluidized bed provided in an upper portion of the internal space, in which seed crystals exist, and a treated water supply means for supplying the treated water to the fluidized bed directly to the fluidized bed or through the pressure chamber. An upper part of the fluidized bed by bringing the target component in the treated water supplied to the fluidized bed by the treated water supply means into contact with the seed crystal and causing the target component to crystallize on the surface of the seed crystal. The circulating water supply means for supplying a part of the treated water obtained through the circulating water supply channel to the pressure chamber as circulating water, and the pressure chamber and the fluidized bed are in communication with each other. Circulating water stored in the pressure chamber and provided in the partition A plurality of distributors that distribute at least one of the water to be treated to the fluidized bed and the chemical used in the crystallization reaction in the circulating water supply channel. A reaction crystallization treatment apparatus comprising a chemical supply means for supplying at least one of a region where a flow is generated and a region where a swirling flow is generated in the circulating water.

[0029] According to the eleventh aspect of the present invention, the drug supply means supplies the drug to at least one of the region where the turbulent flow occurs in the circulating water and the region where the swirl flow occurs in the circulating water in the circulating water supply flow path. Therefore, immediately after the addition, the drug is rapidly and uniformly mixed in the circulating water. As a result, compared to the conventional case where the drug is added to the region where the water flow in the fluidized bed is stable, the local concentration of the drug in the fluidized bed is prevented from increasing, and the drug concentration can be made uniform. As a result, the generation of aggregates is suppressed.

[0030] The reaction tank has corrosion resistance against the water to be treated and the chemicals added thereto. Is preferred. The size of the reaction vessel is not limited. Also, the shape may be a cylindrical shape, or may be a square tube shape that is, 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, and the upper and lower portions of the reaction tank defined by the partition wall can be communicated with each other.

[0031] The pressure chamber is a room partitioned in a reaction tank by a partition wall so that treated water or circulating water is uniformly blown out to the fluidized bed through a plurality of distributors (air outlets). 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 a plurality, it may be divided in the height direction of the reaction tank, or may be divided in the radial direction (plane direction) of the 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. Further, both circulating water and treated water may be used. In addition, 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.

[0032] 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. May be.

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 supply path. A water supply path provided with a supply pump for water to be treated can be employed. 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 flow path. . For example, a supply pump (for example, a circulating water pressure pump or a pump device) may be provided in the circulating water supply channel.

[0033] The material of the distributor is preferably one having 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 attachment hole formed in the partition wall and an upper nozzle umbrella plate standing on the upper surface of each lower nozzle umbrella plate via a plurality of columns. Each of them can be used. This distributor can be used, for example, as a composite supply section 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. Monkey.

The number of distributors used can be changed as appropriate depending on the floor area of the reaction tank as long as it is two or three or more.

As the chemical supply means, for example, a chemical solution supply tank in which a chemical solution obtained by dissolving a drug in water and a pump in which the chemical solution in the chemical supply tank is pumped through the chemical solution supply path can be adopted. . In addition, it is possible to adopt a medicine supply tank that stores 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. .

[0034] A twelfth aspect of the present invention includes a reaction vessel having a cylindrical shape or a rectangular tube shape, and at least a lower portion gradually tapering downward, and reacting a target component in water to be treated. A fluidized bed provided in an internal space of the tank, in which seed crystals exist, a treated water supply means for supplying the treated water to a lower portion of the internal space, and the treated water supply in the fluidized bed. The target component in the for-treatment water supplied by the means is brought into contact with the seed crystal, and the target component is crystallized on the surface of the seed crystal, whereby the upper force of the fluidized bed is obtained. The circulating water supply channel is used for the crystallization reaction, and the circulating water jetting means for spraying the circulating water as the circulating water against the bottom wall of the reaction tank through the circulating water supply channel. To the circulating water in the circulating water supply channel. A reaction crystallization treatment apparatus comprising a chemical supply means for supplying at least one of a region where turbulent flow is generated and a region where swirl flow is generated in the circulating water.

[0035] According to the twelfth aspect of the present invention, 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. An upward flow is generated inside the reaction tank. 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 the circulating water supply flow path in the region where the turbulent flow is generated, the medicine is rapidly and uniformly mixed into the circulating water immediately after the addition. . As a result, compared to the conventional case where the drug is added to a region where the water flow in the fluidized bed is stable, the increase in the concentration of the local drug in the fluidized bed is suppressed, and the drug concentration can be made uniform. . As a result, the generation of aggregates is suppressed.

[0036] The reaction layer may have a cylindrical shape or a rectangular tube shape.

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.

As the circulating water jetting means, a part of the treated water obtained by the crystallization reaction in the fluidized bed is used as circulating water, and the circulating water supply channel force can be jetted by directing to the bottom wall of the reaction tank. If it is, it will not be limited. For example, a circulating water supply channel may be provided with a pump or the like. The speed of circulating water ejected from the circulating water supply channel is, for example, 0.1 to lmZ seconds.

[0037] In the thirteenth or fourteenth aspect of the present invention, in the reaction crystallization treatment apparatus of the eleventh or twelfth aspect, the region where turbulent flow is generated in the circulating water in the circulating water supply flow path is Arrangement part of the stirring blade arranged in the middle of the circulating water supply flow path or the vicinity of the upstream or the vicinity thereof, or the arrangement part of the pressure feed pump arranged in the middle of the circulating water supply flow path or the vicinity of the upstream or Arranged in the vicinity of the downstream water, or in the middle of the circulating water supply flow path, in the middle of the circulating water supply flow path or in the vicinity of the upstream or the downstream thereof And the swirl flow into the circulating water in the circulating water supply flow path at the portion where the drug rapid mixing tank rapidly mixes the drug and the entire circulating water in the drug rapid mixing tank, or in the vicinity of the upstream or downstream thereof. The region where the circulation occurs This is a reactive crystallization treatment apparatus that is located in the middle of the water supply flow path or in the vicinity of the upstream or the downstream thereof.

[0038] According to the fifteenth or sixteenth aspect of the present invention, in the reaction crystallization treatment apparatus of the thirteenth or fourteenth aspect, a stirring blade or a pressure pump is provided in the middle of the circulating water supply flow path. Among the circulating water supply flow path, the arrangement part of the stirring blade or the pressure feed pump or its part A reaction crystallization treatment apparatus in which at least one of a valve, an orifice, and a line mixer is disposed as a means for generating a turbulent flow or a swirling flow in the circulating water of the circulating water supply flow path in the vicinity of the upstream of or downstream of the It is.

The means for generating turbulent 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.

In the reaction crystallization treatment apparatus of the present invention, the chemical supply means supplies the chemical used for the crystallization reaction to a high region of the turbulent strength of the circulating water in the circulating water supply channel. It may be. In the reaction crystallization treatment method and the reaction crystallization treatment apparatus of the present invention, the region where turbulent flow is generated in the circulating water in the circulating water supply channel is a region where turbulent flow is generated due to a sudden change in flow. Also good. The region where the swirling flow is generated in the circulating water of the circulating water supply channel may be a region where turbulent flow is generated by the swirling flow. The invention's effect

[0039] According to the reaction crystallization treatment method of the first and second aspects of the present invention and the reaction crystallization treatment apparatus of the eleventh and first two aspects of the present invention, the circulating water supply passage is circulated. Since the drug is added to the area where turbulent flow occurs in the water so that the drug is rapidly and uniformly mixed in the circulating water, 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.

[0040] In particular, according to the third or fourth aspect of the present invention, by precipitating the calcium phosphate compound on the surface of the seed crystal, the PO-P concentration in the water to be treated containing phosphate phosphorus is number

Four

Even for wastewater of 10 mgZL to several hundred mgZL, it has the effect of reducing the concentration of coagulation and can improve the removal and recovery rate of phosphorus in the reaction crystallization method. As a result, the reaction crystallization treatment apparatus can be made compact. Also, the PO-P concentration is relatively low, l-5mgZL.

Four

For concentration wastewater, treated water with T P <lmgZL can be obtained stably. Brief Description of Drawings

FIG. 1 is a schematic configuration diagram of a reaction crystallization treatment apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a schematic configuration diagram of a reaction crystallization treatment apparatus according to Embodiment 2 of the present invention.

FIG. 3 is a schematic configuration diagram of another reactive crystallization treatment apparatus according to Embodiment 2 of the present invention. FIG. 4 is a schematic configuration diagram of still another reactive crystallization treatment apparatus according to Embodiment 2 of the present invention.

FIG. 5 is a schematic configuration diagram of a reactive crystallization treatment apparatus according to Embodiment 3 of the present invention.

[Fig. 6] Fig. 6 is a schematic configuration diagram of a main part of a reaction crystallization treatment apparatus according to another embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a main part of a reaction crystallization treatment apparatus according to another embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of a reaction crystallization treatment apparatus according to Embodiment 4 of the present invention.

[Fig. 9] Fig. 9 is a graph showing the relationship between PO-P concentration and calcium concentration using pH as a parameter.

Four

It's rough.

FIG. 10 is a schematic configuration diagram of a reaction crystallization treatment apparatus according to conventional means.

Explanation of symbols

10, 10A ~: LOD crystallization dephosphorization equipment (reaction crystallization treatment equipment),

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 (chemical 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 pumping pump,

50A drug rapid mixing tank,

50B line mixer,

51 bulkhead, 61 Stir blade

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Example 1

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 removes phosphorus as a target component in water to be treated. Reaction tank 11 to be reacted, 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 seed crystal provided in the upper part of the internal space Fluidized bed 14, treated water supply tank (treated water supply means) 15 for supplying treated water to pressure chamber 13, phosphorus and seed crystals supplied to fluidized bed 14 by treated water supply tank 15 A part of the treated water, which has also obtained the upper force of the fluidized bed 14 by crystallizing phosphorus on the surface of the seed crystal, is supplied to the pressure chamber 13 through the circulating water supply passage 21 as circulating water. The water supply means 16, the pressure chamber 13 and the fluidized bed 14 are connected to each other in the partition wall 51. A plurality of distributors 12 that distribute at least one of the collected circulating water and treated water to the fluidized bed 14 and slaked lime that stores slaked lime aqueous solution (calcium hydroxide chemical) used for the crystallization reaction An aqueous solution supply tank (medicine supply means) 17 is provided.

[0045] The reaction tank 11 is a straight cylinder type cylindrical tank (or a square 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 is divided into a lower pressure chamber for treated water 19 to which treated water is supplied and an upper pressure chamber for circulating water 20 to which circulating water is supplied. It is partitioned by a partition plate 52.

An annular drainage channel (not shown) is formed on the outer periphery of the upper edge of the reaction tank 11 to drain the treated water after dephosphorization. It is configured to discharge to

[0046] In the central part of the reaction tank 11, a long inner cylinder (circulating water supply flow path) 21 whose lower end communicates with the central part of the pressure chamber 20 for circulating water has its axis as the axis of the reaction tank 11. It is erected in conformity with 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 formed with a diameter-enlarged portion 21a that gradually increases in diameter toward the opening at the upper end. A stirring motor 41 for a pump device that draws treated water to the inner cylinder 21 is erected on the central portion of the reaction tank 11. The output shaft 42 of the stirring motor 41 is long, and an impeller (stirring blade) 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 stirring motor 41, the impeller 22 rotates, and a countercurrent water flow is generated in the inner cylinder 21 downward. As a result, 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 21a through the inside of the inner cylinder 21.

[0048] In addition, a chemical solution supply pipe (chemical solution supply path) in which the slaked lime aqueous solution supply tank 17 and the base portion are communicated with a portion directly above the impeller 22 in the inner cylinder 21 (a region where turbulent flow is generated in the circulating water). The tip of 17a is placed. A solenoid valve and a chemical supply pump (not shown) are disposed in the middle of the chemical supply pipe 17a. Therefore, when the chemical solution 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 solution 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 (treated water supply path) 15a. The treated water supply pipe 15a is provided with a! / ヽ solenoid valve and a treated water supply pump (not shown). By the operation of the treated water supply pump, the 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. In addition, around the fitting holes 51a, six mounting holes 51b- "force S of 60 degrees are formed at intervals of 60 degrees.

Each distributor 12 is connected to a lower nozzle umbrella plate 12a arranged above the corresponding mounting hole 51b and a plurality of support columns (spacers) on each lower nozzle umbrella plate 12a. And has an upper nozzle umbrella plate 12b.

[0050] Of these, each lower nozzle umbrella plate 12a ... is an attachment hole 51b "in the upper wall (partition plate) 52- Is fixed to the opening on the upper side of the blowing nozzle 55. 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 each outlet nozzle 55 to the corresponding lower nozzle umbrella plate 12a and the upper nozzle umbrella plate 12a. Each is ejected to the fluidized bed 14 through a gap with the nozzle umbrella plate 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 blowout nozzles 55, so that the lower part of the lower nozzle umbrella plates 12a. It is ejected from the space to the fluidized bed 14 respectively.

[0051] As the distributor 12, a distributor 12A dedicated to the treated water communicated with the pressure chamber 19 for the treated water, and circulating water from the treated water outlet of the distributor 12A to form the fluidized bed 14. It is also possible to adopt a type having a distributor 12B dedicated to circulating water that has a low outlet and is connected to the circulating water pressure chamber 20 (Fig. 3). As a result, the number of distributors 12A can be reduced and the flow rate of circulating water to the fluidized bed 14 can be increased compared to the distributor 12B.

Further, 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 into the bottom of the fluidized bed 14 through the treated water supply pipe 15a (FIG. 4). . As a result, the pressure chamber of the reaction chamber 11 becomes one. In this case, the water to be treated may be introduced from the side portion of the fluidized bed 14 through the treated water supply pipe 15 a or 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 . Alternatively, the slaked lime aqueous solution or suspension used for the treatment for 7 days may be stored. In the slaked lime aqueous solution supply tank 17, the slaked lime aqueous solution supply tank 17 is automatically supplied 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. Is called. Alternatively, based on the detection signal of the pH sensor provided in the slaked lime aqueous solution supply tank 17, not shown in the figure, slaked lime powder is supplied from the slaked lime supply hot bar through the feeder into the slaked lime supply tank 17 and also provided in the slaked lime supply tank 17. Tap water or treated water is introduced based on the detection signal of the liquid level sensor, not shown!所 Where it is stirred and mixed by a stirrer A fixed pH aqueous solution of slaked lime is produced.

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 controller. The pH of the treated water is detected by the pH sensor 100, and based on the obtained detection data, a predetermined amount of slaked lime aqueous solution is supplied from the pH controller to the chemical solution supply pump from the slaked lime aqueous solution supply tank 17 to the inner cylinder 21. A command is issued.

[0053] Next, a reaction crystallization treatment method of phosphorus components in waste water by the crystallization dephosphorization apparatus 10 according to Example 1 will be described.

As shown in Fig. 1, the inner cylinder 21 is flowing down by an inverter attached to the chemical supply pump so that the pH of the pH sensor 100 installed in the treated water is received and the treated water reaches a predetermined pH. Control the amount of slaked lime solution added to the circulating water (drug addition amount). For example, sewage secondary treated water with a T P (PO-P) concentration of about 1 to 3 mgZL is used as T P <1 mgZL

Four

In the following cases, 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 to the fluidized bed 14 through the circulating water pressure chamber 20 and the distributors 12. In addition, the amount of inflow of treated water is adjusted by a treated water supply pump with an inverter, and is introduced into the treated water pressure chamber 19. Thereafter, the water to be treated is ejected to the fluidized bed 14 as an upward flow through each of the blowout nozzles 55.

[0054] The upward flow rate in the reaction vessel is appropriately changed depending on 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 of 0.5 to 1. Omm or 1.0 to 1.7 mm), the upward flow rate of circulating water is 0.5 to 2 mZ, preferably 0.8 to 1.5mZ min. As a result, the expansion rate of the seed crystals in the fluidized bed is about 140 to 200%. When the expansion rate is less than 140%, it is difficult to obtain a stable fluidized bed. When the expansion rate exceeds 200%, the circulating water circulation flow rate increases, and the power consumption of the circulating water pump (comprising motor 41, shaft 42, and propeller 22). While this is bulky, the density of seed crystals in the fluidized bed decreases, which is disadvantageous for the crystallization reaction.

The circulating water circulation flow rate is obtained from the floor area X of the reaction tank 11 and the upward flow velocity. It depends on. In addition, the circulating water dilutes the water to be treated to prevent PO-P aggregation.

Four

Suppresses and processing speed increases. Thus, it is preferable to use the reaction tank 11 having a shape in which the ratio of the circulating water Z treated water flow rate is about 10.

[0055] In the fluidized bed 14, a water to which a predetermined amount of slaked lime is added as an aqueous solution and water to be treated are introduced into the circulating water as a main component. Therefore, in the fluidized bed 14, a crystallization reaction is performed in which PO—P contained in the water to be treated is precipitated as hydroxyapatite. The reaction

Four

The equation is shown in equation (1) in the background art column. 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 directly above the impeller 22. Therefore, immediately after that, the slaked lime aqueous solution is stirred and mixed with the circulating water rapidly and uniformly by the impeller 22. As a result, compared to the conventional case where the aqueous slaked lime solution is added to the region where the water flow in the fluidized bed is stable, the increase in local slaked lime concentration in the fluidized bed 14 is suppressed, and the fluidized bed 14 The concentration of slaked lime can be made uniform. As a result, the generation of aggregates is suppressed.

[0056] The circulating water supplied to the circulating water pressure chamber 20 through the inner cylinder 21 passes through the gaps between the mounting holes 51b and the blowing nozzles 55 corresponding to the lower nozzle umbrella plates 12a. It is ejected as an upward flow into the fluidized bed 14 through the lower space. 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 treated water and circulating water are mixed in advance as in the prior art and this mixed liquid is supplied to the fluidized bed 14, the generation of aggregates can be suppressed. This is to prevent the possibility of PO-P agglomeration at the point of contact between the circulating water and the treated water containing phosphorus.

Four

. The treated water is discharged to the outside through the drainage channel drainage pipe provided in the upper part of the reaction tank 11. The discharged treated water is neutralized by aeration, acid addition, etc. as necessary.

[0057] When the calcium concentration in the water to be treated is insufficient, an aqueous solution of calcium chloride (CaCl) or the like may be added as necessary. Where to add salty calcium

2

The place may be a storage tank that receives partial internal force treated water immediately before or after the treated water supply pump in the treated water supply pipe 15a. The PO—P concentration in the treated water is about lOOmgZL or less.

Four

When the pH is 7.0 or higher, the pH is not controlled by slaked lime, It is also possible to add only to the portion directly above the impeller 22 to remove phosphorus and to recover. In addition, according to this method, even for wastewater with a PO-P concentration of several tens of mgZL to several hundred mgZL.

Four

It is effective in reducing the aggregation concentration and can increase the removal and recovery rate of phosphorus in the reaction crystallization method. Thereby, the reaction crystallization treatment apparatus can be made compact.

Next, with reference to FIG. 2, a reaction crystallization treatment method and apparatus according to Example 2 of the present invention will be described.

As shown in FIG. 2, in the crystallization dephosphorization apparatus 10A according to Example 2 of the present invention, the circulating water supply means 16 of Example 1 is removed. In addition, an annular drainage channel 11a is provided in the upper part of the reaction tank 11 along the peripheral wall. The drainage channel 11a and the circulating water pressure chamber 20 are connected to a circulating water supply flow pipe (circulation). (Water supply channel) Communicates with 21A. A circulating water pressure pump 50 is provided downstream of the circulating water supply flow pipe 21A. In addition, the tip of the chemical solution supply pipe 17a, in which the slaked lime aqueous solution supply tank 17 and the base part are connected, is communicated with 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.

[0059] In the reaction crystallization treatment method using the crystallization dephosphorization apparatus 10A, the circulating water pressure feed pump 50 operates 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. Is done. 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, the slaked lime aqueous solution flowing into the circulating water supply flow pipe 21A is immediately and uniformly mixed with the circulating water by the stirring force of the circulating water pump 50.

Since other configurations, operations, and effects are in a range that can be inferred from the first embodiment, description thereof is omitted.

Next, with reference to FIG. 5, a reaction crystallization treatment method and apparatus according to Embodiment 3 of the present invention will be described.

As shown in FIG. 5, in the crystallization dephosphorization apparatus 10B to which the reaction crystallization treatment method according to Example 3 of the present invention is applied, instead of the slaked lime aqueous solution supply tank 17 of Example 2, the average particle size is changed. A slaked lime powder supply tank (chemical supply tank) 17A into which powdered slaked lime is charged A circulating water pump 50 is installed upstream of the circulating water supply pipe 21A. And, in 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 immediately before the circulating water pressure feed pump 50. The branch pipe 21b communicates with the tip of the chemical supply pipe 17b of the slaked lime powder supply tank 17A. A powder pump and a solenoid valve (not shown) for supplying a drug are disposed in the middle of the drug supply pipe 17b. 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 eventually becomes a slaked lime aqueous solution and flows into the pressure chamber 20 for circulating water.

[0061] In the reaction crystallization treatment method by the crystallization dephosphorization apparatus 10B of Example 3, when the circulating water pressure pump 50 is operated, the circulating water in the drainage channel 11a is circulated through the circulating water supply flow pipe 21A. Supplied to the water pressure chamber 20. At this time, the slaked lime powder derived from the slaked lime powder supply tank 17A is supplied to the portion of the circulating water supply flow pipe 21A immediately before the circulating water pumping pump 50 through the chemical supply pipe 17b and the branch pipe 21b. The Therefore, immediately after the slaked lime powder is added, it is rapidly and uniformly stirred and mixed with the circulating water by the stirring force of the circulating water pressure pump 50.

[0062] In addition, the branch pipe 21b is removed in the crystallization dephosphorization apparatus 10B, and a rapid drug mixing tank 50A is provided in a portion where the circulating water supply flow pipe 21A communicates with the branch pipe 21b. It may be configured to rapidly stir and mix the water and circulating water! ヽ (Fig. 6). The rapid drug mixing tank 5 OA is a small tank that can hold the circulating water for 10 seconds or more, and a large output stirrer 60 is attached to the small tank. The slaked lime powder charged in the tank and all the circulating water liquid in the tank are rapidly stirred and mixed by the stirrer 60.

Further, in the crystallization dephosphorization apparatus 10B shown in FIG. 5, a line mixer 50B is provided in a portion between the circulating water supply flow pipe 21A and the circulating water pumping pump 50 between the communicating section with the branch pipe 21b. Yes (Figure 7). The line mixer 50B is a non-powered cylindrical mixer in which a large number of stirring protrusions are arranged on the inner wall of the flow channel at a predetermined pitch in the flow channel length direction. The circulating water to which the slaked lime powder is added passes through the internal channel of the line mixer 50B, so that a swirling flow is generated in the channel, 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 the second embodiment. I will omit the description.

Next, with reference to FIG. 8, a reaction crystallization treatment method and apparatus according to Embodiment 4 of the present invention will be described.

As shown in FIG. 8, in the crystallization dephosphorization apparatus 10C to which the reaction crystallization treatment method according to Example 4 of the present invention is applied, the straight barrel type cylindrical tank or rectangular tube tank of Example 2 is used. Instead of a certain reaction tank 11, a reaction tank 11A in which the pressure chamber 13 is eliminated and the lower part (bottom part) gradually tapers downward is employed. In addition, 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. The tip of the treated water supply pipe 15a is arranged in the lower part of the reaction tank 11A and slightly above the circulating water supply flow pipe 21A.

[0064] Therefore, when the circulating water is pumped out from the circulating water supply flow pipe 21A to the bottom wall of the reaction tank 11 by the circulating water pump 50 for less than lmZ seconds (here, about lmZ seconds), the reaction tank 1 1 An upward flow is generated inside. The treated water supplied to the reaction tank 11 from the treated water supply pipe 15a rides on this upward flow, and the fluidized bed 14 having a predetermined height is formed.

Other configurations, operations, and effects are substantially the same as those of the second embodiment, and thus description thereof is omitted.

Next, a reaction crystallization treatment method using the reaction crystallization treatment apparatus 10 of Example 1, and a reaction crystallization treatment method of Conventional Example 1 using the reaction crystallization treatment apparatus 10D shown in FIG. Each crystallization experiment is actually carried out by, and the results of water quality analysis of the treated water obtained by these are reported. First, the reaction crystallization treatment apparatus 10D of Conventional Example 1 will be described.

As shown in FIG. 10, the reaction crystallization treatment apparatus 10D of Conventional Example 1 is communicated with the slaked ash aqueous solution supply tank 17 via the chemical solution supply pipe 17a on the upper side of the partition wall 51, and the slaked lime aqueous solution is fluidized to the fluidized bed 14 A chemical solution supply chamber 56 is provided, and a large number of chemical solution blowing nozzles 57 are vertically arranged on the upper wall 56a of the chemical solution supply chamber 56 at a predetermined pitch. Also, a distributor 12C is provided at the upper end of each chemical solution discharge nozzle 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 discharge nozzles 57. Therefore, in the fluidized bed 14, around each distributor 12C… Is growing. Other configurations, operations, and effects are the same as those in the first embodiment.

Next, each crystallization experiment using the reaction crystallization treatment method of Example 1 and the reaction crystallization treatment method of Conventional Example 1 will be described.

The seed crystal used is “wrinkle seed” manufactured by Mitsubishi Materials Corporation, particle size: 0.5 to 1. Omm, main component: calcium silicate hydrate.

The seed crystal filling volume was set to 130 L (liter), the treated 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 by an inverter connected to a chemical solution supply pump so that the treated water had a predetermined pH by a pH sensor 100 installed at the upper part of the fluidized bed 14.

Biologically treated wastewater is used as the water to be treated, and phosphate ions are added with KH PO aqueous solution.

twenty four

And adjusted to a predetermined PO-P concentration. The calcium concentration of treated water is lOmgZL

Four

Therefore, calcium was added to the treated water using an aqueous CaCl solution,

2

Supplied to. The calcium concentration in the treated water in Table 1 is determined by the CaCl aqueous solution.

2

The analysis value after adjusting the concentration. The results are shown in Table 1.

In Table 1, experiment numbers 1 to 10 indicate Test Examples 1 to 10. Moreover, experiment numbers 11-13 show Comparative Examples 1-3.

[0067] [Table 1]

The space velocity (sv) was determined by dividing the flow rate per hour of water to be treated by the seed crystal filling volume. The larger the value, the faster the treatment speed. If the treated water flow rate is the same, the compaction of the equipment can be achieved.

Aggregated phosphorus concentration is {(treated water T P) (treated water PO— P)} {(treated water T P) (treated water

Four

Treated water PO—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 mgZL, PO—P = 0.34 mgZL, and almost treated water. Water quality

Four

It was close. In other experiment numbers 1, 3 to 10, the TP values of the treated water were all lmg ZL or less. In other words, it has been clarified that rapid mixing and stirring of the drug does not cause a high pH state and suppresses aggregation.

[0069] Next, with respect to 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. The seed crystal to be reported was 97% pure fluorite (calcium fluoride) with a particle size adjusted to 0.3 to 0.5 mm.

The seed crystal filling volume was set to 100 L, and the circulating flow rate of the treated water was adjusted by an inverter connected to the stirring motor 41, and the seed crystal expansion rate was set to 150%.

As the water to be treated, simulated waste water using a sodium fluoride reagent and adjusting the fluorine ion concentration to 20 mgZL was used. The treated water flow rate was adjusted with an inverter connected to the treated water supply pump and confirmed with a flow meter.

[0070] As the drug, a 20% calcium chloride aqueous solution was employed. The injection volume was controlled by an inverter connected to the drug injection pump. The drug is injected by proportional control according to the flow rate of the water to be treated.

JIS K 0102 lanthanum-alizarin complexone absorption photometric method was used for the analysis of fluorine ion concentration. The test results are shown in Table 2. In Table 2, Experiment No. 14 shows Test Example 11. Experiment No. 15 represents Comparative Example 4.

As is clear from Table 2, in Experiment No. 14, the concentration of SS (sludge), which causes the cloudiness of the treated water, was also low. On the other hand, in Experiment No. 15, the treated water became cloudy, SS increased, and the fluorine ion concentration increased. This is thought to be 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.

[0071] [Table 2] Actual treated water Treated water

Experiment Space velocity Water / dish Treated water

Experimental lightning Ca SS F Ca SS

SV (/ hour) () status

(mg / L) (mg / L) (mg / L) (mg / L) (mg / L)

Issue

14 Example 1 1 20.B 20 5.2 0.2 5.5 1.0 0.0 Transparent

15 Conventional example 1 1 20.0 21 4.9 0.1 9.6 12.0 15.4 Birch Industrial applicability

The chemical is added to the circulating water supply channel in the area where turbulent flow occurs in the circulating C water, so that the drug is rapidly and uniformly mixed into the circulating water. The rise of is suppressed. As a result, the drug concentration can be made uniform and the generation of aggregates can be suppressed.

By precipitating the calcium phosphate compound on the surface of the seed crystal, the concentration of POP in the water to be treated containing phosphate phosphorus can be reduced even for wastewater of several tens mgZL to several hundred mgZL.

Four

This is effective in reducing the concentration of phosphorus and can increase the removal and recovery rate of phosphorus in the reaction crystallization method. Thereby, the reaction crystallization treatment apparatus can be made compact. Also, for wastewater with a relatively low POP concentration of 1 to 5 mgZL, T P <lmgZL

Four

Treated water can be obtained stably.

Claims

The scope of the claims

[1] By introducing the water to be treated into the fluidized bed in which the seed crystals exist and bringing the water to be treated and the seed crystals into contact with each other in the fluidized bed, the target component in the water to be treated is added to the surface of the seed crystals. Crystallized as a compound to obtain treated water, and a reaction crystallization treatment method in which a part of the treated water as circulating water and a chemical used for the crystallization reaction are introduced into the fluidized bed. The chemical agent is added to at least one of a region where turbulent flow is generated in the circulating water and a region where swirl is generated in the circulating water in the circulating water supply channel of the circulating water. Crystallization method.

[2] The reaction crystallization treatment method according to [1], wherein the water to be treated is introduced into the fluidized bed through a flow path different from the treated water to which the chemical is added.

[3] The treated water is a waste water containing phosphate phosphorus, and the phosphorus content in the waste water is removed and recovered by precipitating the calcium phosphate compound on the surface of the seed crystal.

2. The reaction crystallization treatment method according to 1.

[4] The treated water is wastewater containing phosphate phosphorus, and the phosphorus content in the wastewater is removed and recovered by precipitating the calcium phosphate compound on the surface of the seed crystal.

2. The reaction crystallization treatment method according to 2.

[5] The drug is one or more selected from the group consisting of a calcium compound containing calcium salt and calcium hydroxide containing calcium hydroxide and sodium hydroxide, and

4. The reaction crystallization treatment method according to claim 3, wherein the chemical is added to the circulating water as an aqueous solution or a suspension, or added to the circulating water as a solid.

[6] The drug is one or more selected from the group consisting of calcium compounds including calcium salt and calcium hydroxide including calcium hydroxide and sodium hydroxide, and

5. The reaction crystallization treatment method according to claim 4, wherein the chemical is added to the circulating water as an aqueous solution or a suspension, or is added to the circulating water as a solid.

[7] The seed crystal was selected from the group consisting of calcium silicate hydrate, calcium phosphate, phosphate ore, silica sand, bone charcoal, calcium sulfate, calcium carbonate, and calcium magnesium carbonate.

4. The reaction crystallization treatment method according to claim 3, wherein the reaction crystallization treatment method is one kind or two or more kinds.

[8] The seed crystal includes calcium silicate hydrate, calcium phosphate, phosphate ore, silica sand, bone charcoal, 5. The reactive crystallization treatment method according to claim 4, wherein one or more selected from the group strength of calcium sulfate, calcium carbonate, and calcium magnesium carbonate are selected.

[9] The seed crystals are one or more selected from the group consisting of calcium silicate hydrate, calcium phosphate, phosphate ore, silica sand, bone charcoal, calcium sulfate, calcium carbonate, and calcium carbonate magnesium. Item 6. The reaction crystallization treatment method according to Item 5.

[10] 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 or in the vicinity of the upstream or the downstream thereof. The part of the pressure pump arranged in the middle of the supply flow path, the vicinity of the upstream or the vicinity thereof, or the part of the flow passage cut-off area formed in the middle of the circulating water supply flow path smaller than the other parts Or the upstream vicinity or the downstream vicinity force It is arrange | positioned in the middle of the said circulating water supply flow path, and the arrangement | positioning part of the said chemical | medical agent rapid mixing tank which rapidly mixes the chemical | medical agent and the whole circulating water in a chemical | medical agent rapid mixing tank, or its upstream. Near or downstream

The region where the swirling flow is generated in the circulating water of the circulating water supply flow path is an arrangement portion of the line mixer arranged in the middle of the circulating water supply flow path, the upstream vicinity thereof, or the downstream vicinity thereof. The reaction crystallization treatment method according to any one of claims 9 to 10.

[11] a reaction tank for reacting the 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 directly or 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;

Distributing at least one of circulating water and treated water stored in the pressure chamber to the fluidized bed, provided in the partition with the pressure chamber and the fluidized bed communicating with each other. With multiple distributors,

A chemical supply for supplying the chemical used in the crystallization reaction to at least one of a region where turbulent flow is generated in the circulating water and a region where swirl is generated in the circulating water in the circulating water supply channel. And a reaction crystallization treatment apparatus.

[12] A reaction tank having a cylindrical shape or a rectangular tube shape, and at least a lower portion gradually tapering downward, and reacting a target component in water to be treated;

A fluidized bed provided in the internal space of the reaction vessel and containing seed crystals;

A treated water supply means for supplying the treated water to a lower portion of the internal space; a target component in the treated water supplied by the treated water supply means and the seed crystal in the fluidized bed; A portion of the treated water obtained from the upper part of the fluidized bed by contacting and crystallizing the target component on the surface of the seed crystal, through the circulating water supply channel, A circulating water jetting means for jetting as circulating water with a positional force below the position directed toward the bottom wall of the reaction tank;

Agent for supplying the chemical used in the crystallization reaction to at least one of the circulating water supply flow path, the region where turbulent flow is generated in the circulating water and the region where swirl is generated in the circulating water And a reaction crystallization treatment apparatus.

[13] The region where the turbulent flow is generated in the circulating water in the circulating water supply channel is the portion where the stirring blades are arranged in the middle of the circulating water supply channel, or the vicinity of the upstream or the downstream thereof. The part of the pressure pump arranged in the middle of the supply flow path, the vicinity of the upstream or the vicinity thereof, or the part of the flow passage cut-off area formed in the middle of the circulating water supply flow path smaller than the other parts Or the upstream vicinity or the downstream vicinity force It is arrange | positioned in the middle of the said circulating water supply flow path, and the arrangement | positioning part of the said chemical | medical agent rapid mixing tank which rapidly mixes the chemical | medical agent and the whole circulating water in a chemical | medical agent rapid mixing tank, or its upstream. Near or downstream

12. The region where the swirling flow is generated in the circulating water in the circulating water supply channel is an arrangement portion of a line mixer arranged in the middle of the circulating water supply channel, or the vicinity thereof or the vicinity thereof. The reaction crystallization treatment apparatus described.

[14] The region where the turbulent flow is generated in the circulating water in the circulating water supply channel is the region of the circulating water supply channel. The part of the stirring blade arranged in the middle or the vicinity of the upstream or the vicinity of the downstream force The part of the pressure feed pump arranged in the middle of the circulating water supply flow path, the vicinity of the upstream or the vicinity thereof, or the circulating water The portion where the channel cut-off area formed in the middle of the supply channel is smaller than the other portion or the force in the vicinity of the upstream or the downstream thereof is arranged in the middle of the circulating water supply channel, and in the drug and drug rapid mixing tank In the arrangement part of the chemical rapid mixing tank that rapidly mixes the whole of the circulating water or in the vicinity of the upstream or the downstream thereof,

13. The region where the swirling flow is generated in the circulating water in the circulating water supply channel is the arrangement portion of the line mixer arranged in the middle of the circulating water supply channel, or the vicinity thereof or the vicinity thereof. The reaction crystallization treatment apparatus described.

[15] A stirring blade or a pressure feed pump is provided in the middle of the circulating water supply flow path,

As means for generating a turbulent flow or a swirling flow in the circulating water of the circulating water supply flow path in the circulating water supply flow path, in the vicinity of the arrangement of the stirring blade or the pressure feed pump or in the vicinity of the upstream or the downstream thereof, The reaction crystallization treatment apparatus according to claim 13, wherein at least one of a valve, an orifice, and a line mixer is disposed.

[16] A stirring blade or a pressure pump is provided in the middle of the circulating water supply flow path,

As means for generating a turbulent flow or a swirling flow in the circulating water of the circulating water supply flow path in the circulating water supply flow path, in the vicinity of the arrangement of the stirring blade or the pressure feed pump or in the vicinity of the upstream or the downstream thereof, 15. The reaction crystallization treatment apparatus according to claim 14, wherein at least one of a valve, an orifice, and a line mixer is disposed.