JP5360764B2 - Method and system for simultaneous recovery of ammonia and phosphorus components in water to be treated - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simultaneously recover ammonia and phosphorus components as MAP from water to be treated which water contains the ammonia and phosphorus components. <P>SOLUTION: The method includes the steps of: (1) adsorbing the ammonia component by bringing the water to be treated into contact with a zeolite-based cation adsorbent; (2) adsorbing the phosphorus component by bringing the water to be treated into contact with a hydrotalcite-based anion adsorbent; (3) desorbing the adsorbed components from the zeolite-based cation adsorbent and the hydrotalcite-based anion adsorbent using a common desorption liquid so that cations and anions in the desorption/regeneration liquid can be used without waste, and recovering a solution where the ammonia and phosphorus components coexist; (4) adding an alkali and magnesium ions to the recovered solution to precipitate and separate the ammonia and phosphorus components as MAP, and simultaneously recovering the ammonia and phosphorus components; and (5) reusing the solution after recovering MAP in the step (4) as at least part of the desorption liquid of the step (3). <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to a method for simultaneously recovering ammonia components and phosphorus components from artificial wastewater such as sewage and industrial wastewater, river water and dam lake water, and also livestock wastewater. More specifically, magnesium ion phosphate (MgNH ₄ PO ₄ .xH ₂ O, hereinafter sometimes referred to as “MAP”) after selective ion exchange adsorption of ammonium ions and phosphate ions and simultaneous desorption of these components. This invention relates to a recovery method and a recovery system.

  In recent years, water pollution in public water areas such as rivers and lakes has been improving due to the spread of sewerage. However, in some closed waters, nutrients accumulate and eutrophication has progressed, resulting in water quality problems associated with the abnormal growth of algae. is important.

Conventional nutrient removal techniques include selective ion exchange and MAP. The former is a technique in which an ion exchange adsorbent is brought into contact with water to be treated to adsorb phosphate ions, and then the adsorbed substance is desorbed from the adsorbent and processed. Compared with biological treatment methods, there are advantages such as a high adsorption rate and no generation of sludge, and so far, various adsorbents have been applied. As for the recovery of phosphorus, a method has been devised in which phosphate ions are desorbed from the adsorbent after the adsorption treatment, and finally phosphate ions are recovered from the liquid by the MAP method described later.
The latter MAP method is a technique for recovering not only phosphate ions but also ammonium ions simultaneously by adding ammonia and magnesium to a phosphate ion solution under high pH conditions to crystallize as MAP. Therefore, the effect as a fertilizer is high and there exists an advantage that a recovered material can be used for a fertilizer as it is.

As a method for recovering phosphorus and ammonia by such a MAP method, for example, Patent Document 1 uses a phosphorus adsorbent made of a composite metal hydroxide containing hydrotalcite, and after adsorbing phosphorus components in waste water, Phosphorus component is desorbed with a desorbent containing alkali metal carbonate or alkaline earth metal carbonate, an aqueous solution of ammonia or ammonium salt is mixed in the desorbed solution, and the phosphor component is magnesium phosphate and / or magnesium phosphate. A method for separation as ammonium is described.
However, this method does not describe the separation and effective utilization of the ammonia component in the waste water.

On the other hand, a method for removing an ammonia component from ammonium ion-containing wastewater is also known. For example, Patent Document 2 describes a method for treating ammonium ion-containing water in which ammonium ion-containing water is brought into contact with zeolite to capture ammonium ions in the zeolite, and then the zeolite is regenerated in the presence of nitrous acid or a salt thereof. Has been.
However, this method does not describe simultaneous removal of phosphorus components in waste water.

As an improvement on the above-described method, reports have already been made on the simultaneous removal of phosphorus and ammonia contained in waste water and the recovery of these components as MAP. For example, in Patent Document 3, raw water is passed through a mixed packed bed of granular zeolite and granular activated alumina to remove phosphorus and ammonia by adsorption, and then an alkaline aqueous solution is supplied to the packed bed to remove the adsorbed phosphorus and ammonia. It is described that the packed bed is separated to regenerate, and magnesium ions are added to the resulting regenerated waste liquid to recover phosphorus as magnesium ammonium phosphate.
However, since this method uses a mixed packed bed of granular zeolite and granular activated alumina, there is a risk that the regeneration of the zeolite will be insufficient due to the lack of Na ⁺ during the regeneration, and there is no suggestion about the reuse of the desorption liquid. Absent.

JP-A-2005-305343 JP-A-9-122638 JP-A-9-75921

  Under such circumstances, the present inventors contacted water to be treated containing an ammonia component and a phosphorus component with a cation adsorbent and an anion adsorbent to adsorb ammonia and a phosphorus component, respectively, and use a desorption liquid. In the method of recovering these components by desorbing the adsorbed ammonia and phosphorus components, a specific adsorbent is used for the cation adsorbent and anion adsorbent, and a common desorbent is used as the desorbent. Thus, the present inventors have found that the ammonia component and the phosphorus component can be recovered simultaneously as magnesium ammonium phosphate, and that the solution after recovering the magnesium ammonium phosphate can be reused as a desorption liquid.

In the present invention, a zeolite cation adsorbent (hereinafter sometimes referred to as “Ze”) is used as a cation adsorbent, and a hydrotalcite anion adsorbent (hereinafter referred to as “HT”) as an anion adsorbent. In which the desorption solution can be shared and magnesium ions are added to the ammonia component and the phosphorus component in the desorption solution to separate and remove the ammonia component and the phosphorus component as MAP. It is concerned.
The present invention also relates to a collection system that embodies these methods.

That is, the present invention includes the following inventions [1] to [3] .
[1] A method for simultaneously recovering an ammonia component and a phosphorus component in water to be treated containing the ammonia component and the phosphorus component, including the following steps (1) to (5).
(1) A step of bringing the water to be treated into contact with a zeolite cation adsorbent to adsorb an ammonia component (2) A step of bringing the water to be treated into contact with a hydrotalcite anion adsorbent to adsorb a phosphorus component (3) The zeolite type A step of recovering a solution in which an ammonia component and a phosphorus component coexist by desorbing an adsorbing component from a cation adsorbing material and the hydrotalcite-based anion adsorbing material using a common desorbing solution, A step of desorbing the phosphorus component from the anion adsorbent prior to the desorption of the ammonia component from the zeolitic cation adsorbent (4) adding alkali and magnesium to the recovered solution, and adding the ammonia component and phosphorus And (5) the process of recovering the ammonia component and the phosphorus component simultaneously by precipitating and separating the components as magnesium ammonium phosphate (4) a step of reusing the solution after the recovery of magnesium ammonium phosphate, as at least a portion of the desorption liquid of the step (3)
[2] The method for simultaneously recovering an ammonia component and a phosphorus component as described in [1] above, wherein the desorption liquid is an aqueous solution in which carbonates, nitrates, sulfates, and chloride salts are dissolved alone or in a plurality.
[3] A cation adsorption tank that adsorbs an ammonia component by bringing the water to be treated into contact with a zeolitic cation adsorbent;
An anion adsorption tank for adsorbing phosphorus components by bringing the water to be treated into contact with a hydrotalcite-based anion adsorbent;
An ammonia and phosphorus recovery tank for desorbing the adsorbed components from the cation adsorption tank and the anion adsorption tank using a common desorption liquid, and recovering a solution in which the ammonia component and the phosphorus component coexist;
To the recovered solution, alkali and magnesium ions are added, the ammonia component and the phosphorus component are precipitated and separated as magnesium ammonium phosphate, and a magnesium ammonium phosphate production tank for simultaneously recovering the ammonia component and the phosphorus component,
A simultaneous recovery system of an ammonia component and a phosphorus component, wherein the solution after recovering magnesium ammonium phosphate by the separation means is reused as at least part of the desorption liquid of the desorption means.

In the present invention, it is possible to simultaneously recover the ammonia component and the phosphorus component in the water to be treated, the desorption process is more efficient than the conventional method, and the desorption liquid can be reused, thereby reducing the cost. is there. Further, at the time of MAP generation, the magnesium component must be supplied. Regarding the ammonia supply, it is not necessary to add ammonia at least by using the ammonia component desorbed from the cation adsorbent, or at least the addition of the ammonia component. As a result, the technology can be applied not only to sewage drainage rich in ammonia and phosphate ions, but also to the direct purification of natural water such as river water and dam lake water where pollution is a problem. It can be applied to livestock wastewater. Especially in dam lakes, the growth of algae caused by eutrophication has become an issue, so the present invention is promising as a countermeasure against phosphorus involved in eutrophication.

It is a schematic flowchart of the simultaneous collection | recovery system of the ammonia component of this invention, and a phosphorus component. It is a block diagram of the simultaneous collection | recovery system of the ammonia component and phosphorus component in embodiment of this invention. It is an adsorption isotherm and Langmuir plot figure of HT and Ze. It is a relationship figure of the desorption rate of HT and Ze, and a desorption component / desorption liquid composition.

Hereinafter, the present invention will be specifically described with reference to FIG.
Here, in the present invention, the ammonia component includes ammonia and ammonium ions, and the phosphorus component refers to all ionic forms of phosphorus (phosphate phosphorus) such as phosphoric acid and phosphonic acid. These phosphate ions are sometimes simply referred to as “phosphate ions”.

First, the present invention relates to a method for simultaneously recovering an ammonia component and a phosphorus component in water to be treated containing the ammonia component and the phosphorus component, including the following steps (1) to (5) shown in FIG.
(1) A step of bringing the water to be treated into contact with the zeolite cation adsorbent to adsorb the ammonia component (2) A step of bringing the water to be treated into contact with the hydrotalcite anion adsorbent to adsorb the phosphorus component (3 ) A solution in which an ammonia component and a phosphorus component coexist by desorbing an adsorbent component (also referred to as “adsorbate”) from the zeolite cation adsorbent and the hydrotalcite anion adsorbent using a common desorption liquid. (4) The alkali and magnesium ions are added to the recovered solution, and the ammonia component and the phosphorus component are precipitated and separated as magnesium ammonium phosphate (MgNH ₄ PO ₄ .xH ₂ O), and the ammonia component and Step (5) of simultaneously collecting phosphorus components In step (4), the solution after recovering magnesium ammonium phosphate is treated with the above process. (3) a step of re-use as at least part of the desorption solution

  In the present invention, to-be-treated water containing an ammonia component and a phosphorus component is one that simultaneously contains an ammonia component and a phosphorus component, and is a domestic and industrial wastewater discharged from human society, and a river rich in ammonia and phosphorus. Water and lake water are examples.

Step (1) is a step of adsorbing the ammonia component by bringing the water to be treated into contact with the zeolite cation adsorbent.
The zeolitic cation adsorbent used in the step (1) of the present invention is a cation adsorbent mainly composed of zeolite, and is any one of natural, artificial and synthetic represented by the following chemical composition formula 1). An adsorbent composed mainly of such zeolite or a zeolite-like compound having a function equivalent to that of zeolite can be used.
_{M 2 / n O · Al 2} O 3 · xSiO 2 · yH 2 O 1)
(In the formula, n represents the valence of the cation M, x represents a number of 2 or more, and y represents a number of 0 or more.)
Examples of the zeolite-like compound include clinobutyrite, mordenite, and synthetic zeolite. Since zeolite is obtained in powder form, it is generally used in the form of granulation or support on a carrier. As the zeolitic cation adsorbent of the present invention, for example, the trade name “Cyculus” manufactured by Chubu Electric Power Co., Inc. or the zeolitic miracle sol (Ze-FWG) manufactured by Nippon Construction Technology Co., Ltd. can be suitably used.

Step (2) is a step of adsorbing the phosphorus component by bringing the water to be treated into contact with the hydrotalcite-based anion adsorbent.
The hydrotalcite-based anion adsorbent used in step (2) of the present invention is an anion adsorbent mainly composed of hydrotalcite, and is a natural hydrotalc represented by the following chemical composition formula 2) Sites or adsorbents composed mainly of synthesized hydrotalcite-like compounds can be used.
[M ²⁺ _1-X M ³⁺ _x (OH) ₂ ] [A ^n- _{x / n} · mH ₂ O] 2)
(Wherein, M ²⁺ and M ³⁺ are divalent and trivalent metal ions, A ^n- _{x / ⁿ} denotes the interlayer anions.)
Examples of hydrotalcite-like compounds include manasseite, pyroaurite, and green rust.
Since hydrotalcite is a fine powder, it is generally used by attaching hydrotalcite to a ceramic carrier with a binder. As the hydrotalcite-based anion adsorbent of the present invention, Acriton manufactured by Tokemi Co., Ltd. can be suitably used.

  In the present invention, either step (1) or step (2) may be performed first. In FIG. 1, the zeolitic cation adsorbent is installed between the first sedimentation basin and the aeration tank. However, in order to avoid clogging of the zeolitic cation adsorbent due to suspended solids, it is installed after the final sedimentation basin. It is also possible. In that case, a zeolite cation adsorbent and a hydrotalcite anion adsorbent are continuously installed.

Next, in the present invention, in step (3), the adsorbate is desorbed from the zeolite-based cation adsorbent and the hydrotalcite-based anion adsorbent using a desorption liquid so that the ammonia component and the phosphorus component coexist. Collect the solution.
As the desorption liquid, an aqueous solution in which carbonates, nitrates, sulfates and chlorides are dissolved singly or plurally can be used. Of these, aqueous solutions of chloride salts such as sodium chloride, potassium chloride, lithium chloride, sodium fluoride, potassium fluoride, lithium fluoride, sodium bromide, potassium bromide, and magnesium chloride are preferably used. Alternatively, an aqueous solution of potassium chloride is more preferably used. From the economical aspect, so-called seawater can be used.

The concentration of the desorbing agent in the aqueous solution is about 0.1 mol / kg to 20 mol / kg, and the pH of the phosphorus desorbing solution 1 is about 10 to 14, preferably 12 or more.
The time required for regenerating the phosphorus adsorbent with the desorption liquid (desorption of phosphate ions) is about 1 to 24 hours. The time required for regeneration of the ammonia adsorbent (desorption of ammonium ions) is about 1 to 4 hours.

  In the present invention, it is possible to share one desorption liquid in the desorption process of both the ammonium ion and phosphate ion adsorbents, and to improve the efficiency of the desorption process, such as efficient use of the desorption liquid and reduction of the amount used. one of.

As the order of circulation of the desorption liquid, it is preferable to use the high pH value in the phosphorus component desorption process from the hydrotalcite-based anion adsorbent and subsequently desorb the ammonia component from the zeolite-based cation adsorbent. That is, it is preferable to use a desorption liquid so that the adsorption component to the hydrotalcite-based anion adsorbent is first desorbed and then the adsorption component to the zeolite-based cation adsorbent is desorbed. By doing so, it is possible to use surplus Na ⁺ added in the phosphorus component desorption process from the hydrotalcite-based anion adsorbent for desorption of the ammonia component from the zeolite-based cation adsorbent. On the other hand, since the ammonia component desorbed from the zeolite cation adsorbent exists as free ammonia at high pH, before the next step of desorbing the phosphorus component from the hydrotalcite anion adsorbent There is a risk of splashing from within the system.

Next, in the present invention, in step (4), alkali and magnesium ions are added to the recovered solution, and precipitated and separated as magnesium ammonium phosphate (MAP), and ammonia and phosphorus are simultaneously recovered.
Examples of the alkali include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, calcium hydroxide, magnesium hydroxide, etc. Among them, sodium hydroxide is preferably used.

Moreover, as magnesium ion, aqueous solutions, such as magnesium chloride and magnesium hydroxide, can be used. Magnesium ions are preferably added in excess of phosphate ions in the recovered solution, and more preferably 5 times mol or more. The use of seawater as the magnesium ion source is recommended from an economic point of view.
In addition, when the stoichiometry of the ammonia component and the phosphorus component in the desorption liquid does not match and the phosphorus component is excessive, it is preferable to add the ammonia component. Conversely, when the ammonia component is excessive, it is preferable to remove excess ammonia out of the system by stripping or the like.

Finally, in the present invention, in the step (5), the solution after recovering the magnesium ammonium phosphate in the step (4) is reused as at least a part of the desorption liquid in the step (3).
In re-use, sodium chloride is added as necessary, pH is adjusted to 12 or more, and then recycled as a desorption liquid in the step (3). As a result, the desorption liquid can be effectively used without being discarded.

  Next, with reference to FIG. 2, an embodiment of a system for simultaneously recovering an ammonia component and a phosphorus component in water to be treated incorporating the steps (1) to (5) of the present invention will be described. FIG. 2 is a block diagram of the simultaneous recovery system of the ammonia component and the phosphorus component of the present invention.

  Usually, the organic waste water 10 as the treated water such as sewage, river water, dam lake water, etc. containing ammonia component and phosphorus component is first stored in the sedimentation basin (first sedimentation basin 1). In the first sedimentation basin 1, suspended solids that can be removed by natural sedimentation are removed. Next, the water to be treated is treated in a Ze adsorption tank 4 as a zeolite cation adsorption tank that is brought into contact with a zeolite cation adsorbent and adsorbs an ammonia component to remove the ammonia component (step (1)). . Thereafter, the water to be treated is introduced into the sedimentation basin (final sedimentation basin 3) after aeration treatment is performed in the aeration tank 2 to remove organic substances. In addition, this sedimentation basin can provide an intermediate sedimentation basin according to the kind and capacity | capacitance of drainage. Next, after the water to be treated is treated in the HT adsorption tank 5 as a hydrotalcite-based anion adsorption tank that is brought into contact with the hydrotalcite-based anion adsorbent and adsorbs the phosphorus component, the phosphorus component is removed ( Step (2)), the treated water 11 is subjected to a general treatment such as activated sludge treatment.

  On the other hand, in order to recover the ammonia component and the phosphorus component adsorbed and removed from the water to be treated, a common desorption is performed from the zeolite cation adsorbent in the Ze adsorption tank 4 and the hydrotalcite anion adsorbent in the HT adsorption tank 5. The adsorbed component is desorbed using the liquid, and the solution in which the ammonia component and the phosphorus component coexist is recovered in the ammonia and phosphorus recovery tank 6 (step (3)). In this case, in order to efficiently perform desorption, it is preferable to first desorb the phosphorus component from the hydrotalcite-based anion adsorbent, and then desorb the ammonia component from the zeolite-based cation adsorbent.

  Next, in order to simultaneously recover the ammonia component and the phosphorus component from the desorption recovery solution of the ammonia and phosphorus recovery tank 6, pH is adjusted by adding alkali to the recovery solution, and further n magnesium ions are added in the MAP generation tank 7 Then, it is precipitated and separated as magnesium ammonium phosphate, and the ammonia component and the phosphorus component are recovered simultaneously (step (4)).

  By the way, in the MAP method, the molar ratio of ammonium ions and phosphate ions needs to be equal, but when the MAP method is applied directly to sewage, ammonium ions tend to be excessive. In the recovery system of the present invention, it is possible to control with the use ratio of Ze and HT as a countermeasure against excessive ammonium ions. As another method, ammonia can be removed by a stripping method. Note that the stripping removal of ammonia can be easily performed by introducing air into the recovery tank 6. Since the collection | recovery system of this invention performs a to-be-processed water MAP production | generation process by another system | strain, there are few buffer substances and the production | generation of a scale is suppressed. In addition, since the system is operated on the alkali side, a stripping operation can be easily performed.

  The solution after recovering the ammonia component and phosphorus component is added with a chloride salt such as NaCl and adjusted to pH, and then reused as a common desorption solution in step (3) (step (5)). .

  As described above, the phosphorus recovery method of the present invention is characterized by the combined use of both cation and anion exchange adsorbents and one-solution / conjugate desorption / regeneration with NaCl or the like. Conventionally, ammonia was separately added at the time of phosphorus recovery, but this technology uses ammonia recovered from wastewater, so that phosphorus and ammonia can be recovered simultaneously. In addition, the amount of the desorption liquid used can be reduced and the disposal / treatment of insoluble ions can be avoided as compared with the case where each of the cation and anion adsorbents is used alone. As a result, both ammonium ion and phosphate ion components can be maintained at a high concentration in one solution, and the recovery efficiency of phosphorus can be improved. Conventionally, desorbed ammonia has to be treated separately, but the present invention has an advantage that it can be recovered simultaneously with phosphorus.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

The following adsorbents were used to perform adsorption tests and desorption tests.
1. Adsorbent used (1) Zeolite-based cation adsorbent (referred to as “Ze (1)”)
Product name: Cyculous Na type granular product (Chubu Electric Power Co., Ltd.)
Chemical _{formula: Na 2 O · Al 2 O} 3 · 2SiO 2 · 4.5H 2 O
Particle size: 0.8-2.0mm
(2) Hydrotalcite-based anion adsorbent (referred to as “HT (1)”)
Product name: Acriton (Tokemi Co., Ltd.) Chemical composition formula:
_{Mg 0.683 Al 0.317 (OH) 1.995} (CO 3) 0.028 Cl 0.226 · 0.54H 2 O
Particle size: 2.0-5.0mm

2. Adsorption test Using the granular HT (1) and Ze (1), the adsorption amount of each adsorbent was determined. The adsorption isotherm was prepared by adding Na ₂ HPO ₄ aqueous solution (1 to 80 mg P / L) and NH ₄ Cl aqueous solution (1 to 30 mg / L) having different initial concentrations to HT (1) and Ze (1), respectively. Stirring was performed at 20 ° C. until the equilibrium was reached. The pH was adjusted to 7.0 with HCl and NaOH. After stirring, the equilibrium concentration was measured, and the adsorption amount was calculated from the difference from the initial concentration.

3. Desorption test In the desorption experiment, HT (1) and Ze (1) on which the adsorbate was adsorbed up to the saturated adsorption amount obtained in the adsorption experiment were immersed in a desorption solution having the same composition, and the desorption amount was measured. As the desorption solution of HT (1), 200 mL of 0.25, 0.75 mol-NaOH / kg alkaline aqueous solution was used, and Cl ⁻ was 1, 10, 100, 1000 mol with respect to 1 mol of the adsorptive component, respectively. Prepared with NaCl.
Desorption solution ze (1) is a composition and HT (1) desorption solution using the same thing, since Na ⁺ is required for desorption of NH ₄ ⁺ is added even NaOH, Na amount added ( Calculated as [NaCl] + [NaOH]) / [NH ₄ ⁺ ].

4). Test Result (1) Adsorption Test Result FIG. 3 (a) shows the adsorption isotherm of HT (1), and FIG. 3 (b) shows the adsorption isotherm of Ze (1). In addition, Langmuir plots, which are the reciprocal plots, are shown in FIGS. 3 (a) and 3 (b), respectively. Ze (1) has one linear relationship in the plot. However, for HT (1), a linear relationship is established between two regions of low concentration and high concentration, with 1 / Ce = 8.42 (initial concentration = 10 mg / L) as a boundary. When the following Langmuir equation is applied, the saturated adsorption amount can be obtained from the intercept, but since this phosphorus recovery method assumes the treatment of wastewater with low phosphorus concentration, HT (1) is saturated with the value obtained from the intercept on the low concentration side. Adsorption amount.
(Where q _e is the equilibrium adsorption amount (m mol / g), q _s is the saturated adsorption amount (m mol / g), C _e is the equilibrium concentration (m mol / l), and a is a constant. .)

(2) Desorption test FIG. 4A shows the test results of desorbing the phosphorus component of the adsorbate with HT (1) on which phosphorus was saturated and adsorbed with an alkaline saturated NaCl aqueous solution. As can be seen from the figure, the HT (1) was immersed in 200 ml of a desorption solution of 0.75 mol-NaOH / L and 5.0 mol / L, which is 1,000 times the amount of adsorbed phosphorus. Among the 1.00 mmol of adsorbed phosphorus, 0.977 mmol of phosphorus could be desorbed at a desorption rate of 97.7%.
On the other hand, the desorption experiment of Ze (1) was performed by immersing Ze (1) that was saturated with NH ₄ ⁺ using the desorption liquid used for phosphorus desorption of HT (1). The result is shown in FIG. 4B, and 1.26 mmol of a saturated adsorption amount of 1.26 mmol-NH ₄ ⁺ was recovered with a desorption rate of 96%.
The recovered desorption solution was able to accumulate phosphate ions and ammonium ions at concentrations sufficient for MAP production, and the pH of the used desorption solution was 13.2.

5. Formation of MAP The pH of the recovered desorption solution is adjusted to 10, and 5 times molar amount of Mg ions are added to phosphate ions in the form of MgCl ₂ aqueous solution, so that the phosphorus component and ammonia component in the desorption solution are phosphoric acid. The precipitate was separated as magnesium ammonium. As a result, 96% of the phosphorus component in the desorption solution was insolubilized and recovered as MAP.

6). Reuse of recovered liquid The remaining liquid obtained by insolubilizing and recovering MAP from the desorbed liquid maintained the state of Na ⁺ and Cl ⁻ close to the saturated concentration, but the pH was adjusted from 13 to 10 to generate MAP. As a shortage of alkali to reuse. Therefore, it was confirmed that a short amount of alkali (NaOH) was added and the pH was raised to 13 or more, so that it could be reused as a desorption liquid.

7). Reuse of adsorbent To examine the reuse of adsorbent after desorption of phosphorus or ammonia, HT (1) after desorption was immersed in an aqueous 3.68 mol / L MgCl ₂ solution for 24 hours to resorb the phosphorus. The amount of adsorption was measured. As a result, the re-adsorption amount was 90% with respect to the initial adsorption amount. This is because the structure of HT (1) was reconstructed by bringing HT (1) into contact with MgCl ₂ .
The re-adsorption amount of Ze (1) was 98% of the initial adsorption amount.

  The present invention is not only applied to sewage drainage rich in ammonia and phosphate ions, but also applied to direct purification of natural water such as river water and dam lake water where pollution is a problem, and to livestock drainage Is possible. Particularly in the dam lake, the growth of algae caused by eutrophication has become a problem, and therefore the present invention is promising as a countermeasure against phosphorus.

DESCRIPTION OF SYMBOLS 1 First sedimentation tank 2 Aeration tank 3 Final sedimentation tank 4 Ze adsorption tank 5 HT adsorption tank 6 Ammonia and phosphorus collection tank 7 MAP production tank 10 Organic waste water 11 Treated water

Claims (3)

A method for simultaneously recovering an ammonia component and a phosphorus component in water to be treated containing an ammonia component and a phosphorus component, comprising the following steps (1) to (5):
(1) A step of bringing the water to be treated into contact with the zeolite cation adsorbent to adsorb the ammonia component (2) A step of bringing the water to be treated into contact with the hydrotalcite anion adsorbent to adsorb the phosphorus component (3 ) Recovering a solution in which the ammonia component and the phosphorus component coexist by desorbing the adsorbent component from the zeolite cation adsorbent and the hydrotalcite anion adsorbent using a common desorption liquid , Step of desorbing phosphorus component from hydrotalcite-based anion adsorbent prior to desorption of ammonia component from zeolite-based cation adsorbent (4) Adding alkali and magnesium ions to the recovered solution , Ammonia component and phosphorus component are precipitated and separated as magnesium ammonium phosphate, and ammonia component and phosphorus component are recovered simultaneously Extent (5) in the step (4), a step of reusing the solution after the recovery of magnesium ammonium phosphate, as at least a portion of the desorption liquid of the step (3) The method for simultaneous recovery of ammonia and phosphorus according to claim 1, wherein the desorption liquid is an aqueous solution in which carbonates, nitrates, sulfates, and chloride salts are singly or plurally dissolved. A cation adsorption tank for adsorbing ammonia components by bringing the water to be treated into contact with the zeolite cation adsorbent;
An anion adsorption tank for adsorbing phosphorus components by bringing the water to be treated into contact with a hydrotalcite-based anion adsorbent;
An ammonia and phosphorus recovery tank for desorbing the adsorbed components from the cation adsorption tank and the anion adsorption tank using a common desorption liquid, and recovering a solution in which the ammonia component and the phosphorus component coexist;
To the recovered solution, alkali and magnesium ions are added, the ammonia component and the phosphorus component are precipitated and separated as magnesium ammonium phosphate, and a magnesium ammonium phosphate production tank for simultaneously recovering the ammonia component and the phosphorus component,
A simultaneous recovery system of an ammonia component and a phosphorus component, wherein the solution after recovering magnesium ammonium phosphate by the separation means is reused as at least part of the desorption liquid of the desorption means.