JP2017131819A - Water treatment method, water treatment apparatus, and water treatment system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treatment method capable of efficiently removing organic matters in water by accelerated oxidation.SOLUTION: A water treatment method includes a step for preparing object water containing a manganese ion, a step for producing the object water containing a manganese ion, and a step for recovering the manganese ion. In the step for preparing the object water containing a manganese ion, raw water is supplied with the manganese ion to prepare the object water containing a manganese ion of a concentration of 0.01-10 mg/L. In the step for producing the object water containing a manganese ion, organic matters are removed by accelerated oxidation by supplying a pH adjusting agent and ozone to the object water containing a manganese ion so that a pH value (X) and an oxydation reduction potential (Y, unit: V) measured using a standard hydrogen electrode may satisfy a predetermined equation, and the object water containing a manganese ion is thus produced. In the step for recovering the manganese ion, the manganese ion in the object water containing a manganese ion is recovered.SELECTED DRAWING: Figure 5

Description

  Embodiments described herein relate generally to a water treatment method, a water treatment apparatus, and a water treatment system.

  Recently, due to industrial development and population increase, effective use of water resources is required. In order to effectively use water resources, it is important to purify and reuse various wastewaters such as industrial wastewater and domestic wastewater. In order to purify the wastewater, it is necessary to separate and remove water insoluble matters and impurities contained in the water.

Examples of a method for separating organic substances contained in water include oxidation treatment using ozone and the like, and accelerated oxidation treatment for generating active species called OH radicals. In particular, accelerated oxidation treatment is used as advanced wastewater treatment because organic substances can be decomposed into carbon dioxide by the strong oxidizing power of OH radicals. Examples of the accelerated oxidation treatment include ozone + hydrogen peroxide, ozone + ultraviolet light, ozone + hydrogen peroxide + ultraviolet light, iron ion + hydrogen peroxide (Fenton reaction), ozone + catalyst, ultraviolet light + photocatalyst, and the like.
The accelerated oxidation treatment using a catalyst has an advantage that a chemical does not have to be added to water, and various studies have been conducted. For example, a water treatment method is known in which a flocculant containing manganese or a manganese compound is added to water to be treated, and after ozone treatment in the presence of manganese ions, manganese dioxide produced by the ozone treatment is removed by biological filtration. ing.

  However, in a water treatment method in which a catalyst is added to water to be treated, it is difficult to control the activity of the catalyst, the activity of the catalyst is lowered, and the organic substance removal efficiency may be reduced.

Japanese Patent No. 3178975

  The problem to be solved by the present invention is to provide a water treatment method, a water treatment apparatus and a water treatment system that can efficiently remove organic substances in water by accelerated oxidation.

The water treatment method of an embodiment is a water treatment method for removing organic matter in raw water containing organic matter by accelerated oxidation, and a step of preparing treated water containing manganese ions and generating treated water containing manganese ions And a step of recovering manganese ions.
In the step of preparing the manganese ion-containing treated water, manganese ions are supplied to the raw water to prepare manganese ion-containing treated water having a manganese ion concentration in the range of 0.01 mg / L to 10 mg / L. The step of generating the manganese ion-containing treated water includes X which is a pH value of the manganese ion-containing treated water, and Y (unit: V) which is a redox potential value measured using a standard hydrogen electrode as a reference electrode. In order to satisfy the following formula, a pH adjuster and ozone are supplied to the manganese ion-containing treated water, organic matter in the manganese ion-containing treated water is removed by accelerated oxidation, and manganese ion-containing treated water is obtained. Is generated.
2 ≦ X ≦ 5
0.8 ≦ Y ≦ 1.5−0.08 × X
The step of recovering manganese ions recovers manganese ions in the manganese ion-containing treated water.

Theoretical state figure (Eh-pH figure) which shows the form of manganese in the thermodynamic equilibrium state of manganese aqueous solution. The phase diagram which shows the form of manganese in the manganese aqueous solution containing organic substance. The graph which shows the time-dependent change of Eh and ozone concentration when ozone is supplied continuously, maintaining pH at 2 about the manganese aqueous solution containing organic substance. The graph which shows the time-dependent change of Eh and ozone concentration when ozone is continuously supplied about manganese aqueous solution containing organic substance, maintaining pH at 3.6. The schematic diagram of the water treatment system which concerns on 1st Embodiment. The schematic diagram of the water treatment system which concerns on 2nd Embodiment. The schematic diagram of the water treatment system which concerns on 3rd Embodiment. The graph which shows the relationship between the manganese ion density | concentration measured in Example 1, and the decomposition efficiency of organic substance.

  Hereinafter, a water treatment method, a water treatment apparatus, and a water treatment system of an embodiment will be described with reference to the drawings.

1 is a theoretical state diagram (Eh-pH diagram) showing the form of manganese in a thermodynamic equilibrium state of an aqueous manganese solution (Source of FIG. 1: Geological Survey of Japan Research Center Collection, No. 419, Internet <URL : Https://www.gsj.jp/data/openfile/no0419/openfile419j.pdf>).
In FIG. 1, the horizontal axis represents the pH of the manganese aqueous solution, and the vertical axis represents the oxidation-reduction potential (hereinafter referred to as Eh) of the manganese aqueous solution measured using a standard hydrogen electrode as a reference electrode. From the theoretical state diagram of FIG. 1, it can be seen that manganese ions in the manganese aqueous solution take various forms depending on pH and Eh.

As a result of repeated studies paying attention to the fact that the form of manganese ions in an aqueous manganese solution depends on pH and Eh, the inventors have found that, under certain specific conditions, as shown in the following reaction formula, An intermediate of [MnO] ²⁺ that was not formed was found to be thermodynamically generated, and the pH and Eh value regions are optimal for removing organic substances in water by accelerated oxidation in the presence of manganese ions. Found that there exists. This [MnO] ²⁺ is presumed to have a feature that promotes decomposition by reacting spontaneously with an unsaturated hydrocarbon.

Mn ²⁺ + O ₃ → [MnO] ²⁺ + O ₂ + H ₂ O
ΔE = −39.6 kcal / mol

The above findings will be described with reference to FIGS.
FIG. 2 is a state diagram showing the form of manganese in an aqueous manganese solution containing organic substances (actual measurement value). In FIG. 2, the horizontal axis represents the pH of the manganese aqueous solution, and the vertical axis represents Eh of the manganese aqueous solution. The pH was adjusted with a pH adjuster, and Eh was adjusted with ozone.
When the pH value (X) of the manganese aqueous solution is 2 ≦ X ≦ 5 and the Eh value (Y) is 0.8 ≦ Y ≦ 1.5−0.08X, that is, the pH value and the Eh value are In the case of (II), the organic substance removal efficiency by accelerated oxidation is increased. This is reacted manganese ions in the aqueous solution of manganese is ozone takes [MnO] ²⁺ form, by the [MnO] ²⁺ is to react with the organic material is believed to be due to the removal of organic substances is accelerated .

When the Eh value is higher than the region (II), for example, in the region (I), the form of manganese in water becomes MnO ₄ ⁻ (permanganate). Permanganic acid also decomposes organic substances as an oxidizing agent, but decomposition is accelerated by accelerated oxidation when the Eh value is in the range of (II). On the other hand, when the Eh value is lower than the region (II), accelerated oxidation does not occur at all or is very slow and cannot be used for water treatment.

If the pH value is lower than the region (II), the pH will be too low, so a large amount of chemicals will be required to adjust the pH, and it will be necessary to use a material with high acid resistance as the material constituting the device. It is not preferable. On the other hand, when the pH value is larger than the region of (II), for example, when it is in the region of (III), manganese is easy to take the form of MnO ₂ (S), and the accelerated oxidation does not occur at all. It is slow and cannot be used for water treatment. In addition, when the manganese aqueous solution and manganese compound particle | grains which have pH value and Eh value in the area | region of (III) are made to contact, manganese ion in manganese aqueous solution will precipitate on the surface of manganese compound particle | grains, and will become easy to adsorb | suck.

FIG. 3 is a graph showing temporal changes in Eh and ozone concentration of a manganese aqueous solution when ozone is continuously supplied to a manganese aqueous solution containing an organic substance while maintaining the pH of the manganese aqueous solution at 2. FIG. 4 is a graph showing temporal changes in Eh and ozone concentration of a manganese aqueous solution when ozone is continuously supplied to a manganese aqueous solution containing an organic substance while maintaining the pH of the manganese aqueous solution at 3.6.
As shown in FIGS. 3 and 4, when ozone is supplied to the manganese aqueous solution, the ozone concentration initially increases with the passage of time, but then decreases. On the other hand, the Eh value rises rapidly at the same time as the ozone concentration starts to decrease, and then shows a substantially constant value. The reason for the decrease in the ozone concentration is that ozone is consumed by the reaction of manganese ions in the aqueous manganese solution with ozone to produce [MnO] ²⁺ . Therefore, it is considered that organic substances are being decomposed and removed by accelerated oxidation while the ozone concentration is decreasing and the Eh value is constant. As time further elapses, the ozone concentration and Eh value start to rise. The reason for the increase in the ozone concentration is that [MnO] ²⁺ becomes unnecessary by removing organic substances in the manganese aqueous solution, and ozone is not consumed and remains in the manganese aqueous solution. The reason why the Eh value is increased is that the form of manganese ions becomes MnO ^{4− as} the ozone concentration increases.

  The water treatment method of the embodiment based on the above findings includes a step of preparing treated water containing manganese ions, a step of generating treated water containing manganese ions, and a step of recovering manganese ions.

  Manganese ion-containing treated water has a manganese ion concentration in the range of 0.01 mg / L to 10 mg / L. If the manganese ion concentration is lower than the above range, the substantial catalytic effect may be lowered. On the other hand, if the manganese concentration is higher than the above range, it may be difficult to recover manganese from water.

In the step of preparing the manganese ion-containing treated water, the manganese ion-containing treated water supplies a pH adjuster and ozone to the raw water, and the pH value (X) and Eh value (Y) of the raw water are as follows: It adjusts so that a formula may be satisfied, it can be prepared by contacting raw | natural water and manganese compound particle | grains, and supplying a manganese ion to raw | natural water. By adjusting the pH value (X) of raw water and the Eh value (Y) to satisfy the following formula, manganese is eluted as MnO ⁴⁻ .
2 ≦ X ≦ 5
1.5-0.08 × X <Y

Examples of the manganese compound constituting the manganese compound particles include manganese oxide (eg, MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ ), manganese-containing ferrite (eg, manganese ferrite MnFe ₂ O ₄ ), and manganese. Ore. Moreover, the filtration sand which coat | covered the manganese compound on the surface can also be used as manganese compound particle | grains. The manganese ion concentration of the manganese ion-containing treated water can be adjusted by adjusting the contact time between the raw water and the manganese compound and the Eh and pH of the raw water.
In addition, preparation of manganese ion containing to-be-processed water can also be performed by mixing raw | natural water and manganese aqueous solution.

Further, in the step of recovering manganese ions, manganese ions in the manganese ion-containing treated water are supplied with a pH adjuster and an oxidizing agent such as ozone or hypochlorous acid to the manganese ion-containing treated water. The pH value (X) and Eh value (Y) of water are adjusted so as to satisfy the following formula (that is, within the range of (III) in FIG. 2), It can collect | recover by making a manganese adsorbent particle contact and making a manganese adsorbent particle adsorb | suck a manganese ion.
5 <X ≦ 9
0.6 ≦ Y ≦ 1.5−0.08 × X

  Manganese compound particles and ion exchange resins can be used as the manganese adsorbent particles.

There is no particular limitation on the type of organic matter in the raw water removed by the water treatment method of the embodiment. As a result of the inventors' research, it has been found that the active species [MnO] ²⁺ produced by the reaction of Mn ²⁺ with ozone works particularly favorably in the decomposition of organic substances having a carbon unsaturated bond. Therefore, the water treatment method of the embodiment is effective for removing organic substances having a carbon unsaturated bond. Examples of the organic substance having a carbon unsaturated bond include compounds having a benzene ring represented by phenol and the like, and carboxylic acids represented by oxalic acid and the like. Some of these organic substances are difficult to decompose by oxidative decomposition of ozone alone, but the water treatment method of the embodiment decomposes organic substances by promoting oxidation using [MnO] ²⁺ as a catalyst. It can be removed quickly.

  Next, embodiments of the water treatment method, the water treatment apparatus, and the water treatment system configured based on the above knowledge will be described in more detail.

(First embodiment)
FIG. 5 is a schematic diagram of the water treatment system according to the first embodiment.
The water treatment system 1 of the first embodiment shown in FIG. 5 includes a raw water storage tank (not shown), an accelerated oxidation tank 10, a first packed tower (manganese ion supply apparatus) 20a, and a second packed tower (manganese ion recovery apparatus). 20b and a control device 102.
The raw water storage tank is a tank for storing raw water containing organic matter.

  The 1st packed tower 20a is an apparatus which supplies manganese ion to raw | natural water and prepares manganese ion containing treated water. The first packed tower 20 a is connected to the raw water storage tank via a pipe 301. The pipe 301 includes a pump 50a, a three-way valve 60a, an ozone supply pipe 40a, and a pH adjuster supply pipe 41a. A pipe 302 branches from the three-way valve 60a, and this pipe 302 is connected to a treated water tank (not shown). The ozone supply pipe 40a is a pipe for supplying ozone. Ozone is supplied in a gas state. Ozone is generated and supplied by an ozone generator (not shown). At this time, air or oxygen can be used as a raw material. The pH adjusting agent supply pipe 41a is a pipe for supplying a pH adjusting agent such as an acid, an alkali or a buffer. An example of the acid is sulfuric acid. An example of an alkali is sodium hydroxide. Examples of the buffer include a phosphate buffer.

  The first packed tower 20a is filled with manganese compound particles 201a. The shape of the manganese compound particles 201a is not particularly limited as long as water passage is not hindered, but it is preferably granular with an average particle diameter in the range of 0.1 to 5 mm. In addition, the water flow direction of the first packed tower 20a is not particularly limited, and may be either the upward direction or the downward direction. Moreover, it is good also considering a water flow direction as a horizontal direction. The first packed column 20a includes a sensor (not shown) that measures pH and Eh.

  The accelerated oxidation tank 10 is a tank that removes organic matter in the manganese ion-containing liquid to be treated prepared in the first packed tower 20a by accelerated oxidation to generate manganese ion-containing treated water. The accelerated oxidation tank 10 is connected to the first packed tower 20a via a pipe 303. The pipe 303 includes a pump 50c, an oxidant supply pipe 40d, and a pH adjuster supply pipe 41d. The oxidant supply pipe 40d is a pipe for supplying an oxidant such as ozone or hypochlorous acid. The pipe 303 further has a pipe 304 connected via the three-way valves 60b and 60c. The pipe 304 is a bypass when the pump 50c is not used.

The accelerated oxidation tank 10 is provided with a stirrer 101 for stirring the manganese ion-containing liquid to be processed stored in the accelerated oxidation tank 10. The shape, capacity, material, and the like of the accelerated oxidation tank 10 can be appropriately determined according to the use of the water treatment system 1. The accelerated oxidation tank 10 is not particularly limited, but is preferably made of vinyl chloride or stainless steel that is resistant to ozone.
Further, the accelerated oxidation tank 10 is provided with a sensor 103 that measures the pH and Eh of manganese ion-containing treated water.

  The second packed tower 20 b is a manganese ion recovery device that recovers manganese ions from the manganese ion-containing treated water generated in the accelerated oxidation tank 10. The second packed tower 20b is connected to the accelerated oxidation tank 10 via a pipe 305. The pipe 305 includes a pump 50b, an oxidant supply pipe 40b, and a pH adjuster supply pipe 41b. The pipe 305 further has a pipe 306 connected via three-way valves 60d and 60e. The pipe 306 is a bypass when the pump 50b is not used.

  The second packed tower 20b is filled with manganese adsorbent particles 201b. The shape of the manganese adsorbent particles 201b is not particularly limited as long as water passage is not hindered, but a granule having an average particle diameter in the range of 0.1 to 5 mm is preferable. The manganese adsorbent particles 201b may be particles of a compound different from the manganese compound particles 201a, but are preferably particles of the same compound. Moreover, the water flow direction of the second packed tower 20b is not particularly limited, and may be either upward or downward. Moreover, it is good also considering a water flow direction as a horizontal direction. The second packed column 20b includes a sensor that measures pH and Eh (not shown).

The second packed tower 20b is connected to a raw water storage tank (not shown) via a pipe 307. The pipe 307 includes a pump 50d, a three-way valve 60f, an ozone supply pipe 40c, and a pH adjuster supply pipe 41c. A pipe 308 is branched from the three-way valve 60f, and the pipe 308 is connected to a treatment water tank (not shown).
The treated water tank is a tank for temporarily storing treated water after recovering manganese ions from the manganese ion-containing treated water and then releasing the treated water to the outside.

  The control device 102 operates the pumps 50a, 50b, 50c, 50d and the three-way valves 60a, 60b, 60c, 60d, 60e, 60f to perform water treatment by the water treatment system 1. Moreover, the control apparatus 102 is based on the pH value and Eh value which were measured with the sensor 103 of the acceleration | stimulation oxidation tank 10, and the sensor (not shown) of the 1st packed tower 20a and the 2nd packed tower 20b. The supply amount of the pH adjusting agent and ozone is adjusted so that the water in the first packed column 20a and the second packed column 20b is maintained at an appropriate pH value and Eh value.

Below, the water treatment method using the water treatment system 1 is demonstrated.
First, the pump 50 a is operated, and raw water stored in a raw water storage tank (not shown) is introduced into the first packed tower 20 a through the pipe 301. At this time, ozone is supplied from the ozone supply pipe 40a so that the pH value (X) and Eh value (Y) of the raw water satisfy the above formula (that is, within the region (I) in FIG. 2). The pH adjuster is supplied from the pH adjuster supply pipe 41a. The raw water whose pH value (X) and Eh value (Y) are adjusted in this way is introduced into the first packed tower 20a, and the raw water and manganese compound particles 201a are brought into contact with each other to supply manganese ions to the raw water. By doing so, a manganese ion-containing liquid to be treated is prepared.

  Next, the three-way valves 60 b and 60 c are operated, and the manganese ion-containing liquid to be treated prepared in the first packed tower 20 a is put into the accelerated oxidation tank 10 through the pipe 304.

  Next, the pH value (X) and the Eh value (Y) of the manganese ion-containing treated water satisfy the above formula while stirring the manganese ion-containing treated water with the stirrer 101 in the accelerated oxidation tank 10. As described above (that is, within the region (II) in FIG. 2), ozone is supplied from the ozone supply pipe 104 and pH adjusting agent is supplied from the pH adjusting agent supply pipe 105. In this way, by adjusting the pH value (X) and Eh value (Y) of the manganese ion-containing treated water in the accelerated oxidation tank 10, the organic matter is removed by accelerated oxidation, and the manganese ion-containing treated water is obtained. Produces.

  Next, the pump 50b and the three-way valves 60d and 60e are operated, and the manganese ion-containing treated water generated in the accelerated oxidation tank 10 is introduced into the second packed tower 20b through the pipe 305. At this time, an oxidizing agent is used so that the pH value (X) and the Eh value (Y) of the manganese ion-containing treated water satisfy the above formula (that is, within the region of (III) in FIG. 2). Ozone or hypochlorous acid is supplied from the supply pipe 40b, and a pH adjuster is supplied from the pH adjuster supply pipe 41b. In this way, the manganese ion-containing treated water whose pH value (X) and Eh value (Y) are adjusted is introduced into the second packed tower 20b, and the manganese ion-containing treated water and the manganese adsorbent particles 201b are brought into contact with each other. Then, the manganese ions are collected by adsorbing the manganese ions on the manganese adsorbent particles 201b. The treatment water containing manganese ions may be continuously added to the second packed tower 20b or after accelerated oxidation until organic substances are sufficiently removed in the accelerated oxidation tank 10. May be.

  Next, the three-way valve 60f is operated, and the treated water from which manganese ions have been collected is introduced into a treated water tank (not shown) through the pipe 308.

  When the above water treatment is performed, the manganese of the manganese compound particles 201a in the first packed tower 20a gradually moves toward the manganese adsorbent particles 201b in the second packed tower 20b. Therefore, in the water treatment system 1, treatment can be performed also by flowing raw water from the second packed tower 20b side. That is, after performing the water treatment for a certain time, the water treatment system 1 inputs the raw water stored in the raw water storage tank into the second packed tower 20b to adsorb the raw water and manganese ions. Manganese ion-containing treated water is prepared by bringing particles 201b into contact with each other and supplying manganese ions to the raw water. Then, the manganese ion-containing treated water is introduced into the accelerated oxidation tank 10, and organic matter is introduced into the accelerated oxidation tank 10. Is removed by accelerated oxidation to produce manganese ion-containing treated water, and the manganese ion-containing treated water is charged into the first packed tower 20a to bring the manganese ion-containing treated water into contact with the manganese compound particles 201a. Manganese ions can be adsorbed on the compound particles 201a. By doing this, manganese moves from the manganese adsorbent particles 201b to the manganese compound particles 201a, so that not only can the balance of manganese in the system be maintained, but water can be added without adding a manganese compound from the outside. Processing can be performed.

Below, although the description is the same, the water treatment method in the case of flowing raw water from the second packed tower 20b side will be described.
First, the pump 50d and the three-way valve 60f are operated, and raw water stored in a raw water storage tank (not shown) is introduced into the second packed tower 20b through the pipe 307. At this time, ozone is supplied from the ozone supply pipe 40c so that the pH value (X) and Eh value (Y) of the raw water satisfy the above formula (that is, within the region (I) of FIG. 2). The pH adjuster is supplied from the pH adjuster supply pipe 41c. The raw water whose pH value (X) and Eh value (Y) are adjusted in this way is introduced into the second packed tower 20b, and the raw water and the manganese adsorbent particles 201b adsorbing manganese ions are brought into contact with each other. Then, a manganese ion-containing liquid to be treated is prepared by supplying manganese ions to the raw water.

  Next, the three-way valves 60d and 60e are operated, and the manganese ion-containing liquid to be treated prepared in the second packed tower 20b is put into the accelerated oxidation tank 10 through the pipe 306.

  Next, in the accelerated oxidation tank 10, organic substances are removed by accelerated oxidation to produce manganese ion-containing treated water. The conditions for removing organic substances by promoting oxidation are the same as those described above.

  Next, the pump 50 c and the three-way valves 60 b and 60 c are operated, and the manganese ion-containing treated water generated in the accelerated oxidation tank 10 is introduced into the first packed tower 20 a through the pipe 303. At this time, an oxidizing agent is used so that the pH value (X) and the Eh value (Y) of the manganese ion-containing treated water satisfy the above formula (that is, within the region of (III) in FIG. 2). Ozone or hypochlorous acid is supplied from the supply pipe 40d, and a pH adjuster is supplied from the pH adjuster supply pipe 41d. In this way, the manganese ion-containing treated water whose pH value (X) and Eh value (Y) are adjusted is introduced into the second packed tower 20b, and the manganese ion-containing treated water and the manganese compound particles 201a are brought into contact with each other. Then, the manganese ions are recovered by adsorbing the manganese ions to the manganese compound particles 201a.

  Next, the three-way valve 60a is operated, and treated water from which manganese ions have been collected is introduced into a treated water tank (not shown) through the pipe 302.

  In the water treatment system 1 according to the first embodiment described above, raw water containing organic matter is treated water containing manganese ions containing a predetermined amount of manganese ions, and the pH value (X) and Eh value (Y) thereof are. Since it adjusts so that a predetermined formula may be satisfied, the organic substance in manganese ion containing treated water can be efficiently removed by accelerated oxidation. Moreover, since raw | natural water can be flowed from either the 1st packed tower 20a side or the 2nd packed tower 20b side, even if it does not add a manganese compound from the outside, it becomes possible to perform a water treatment continuously.

(Second Embodiment)
FIG. 6 is a schematic diagram of a water treatment system according to the second embodiment.
In addition, in the following description, the same number is attached | subjected to the structure similar to the water treatment system 1 of 1st Embodiment, and the overlapping description is abbreviate | omitted.

  In the water treatment system 2 of the second embodiment shown in FIG. 6, a raw water storage tank (not shown) and the accelerated oxidation tank 10 are connected via a pipe 309. The pipe 309 includes a pump 50 e and a manganese solution supply pipe 42. This water treatment system 2 is different from the water treatment system 1 in that a manganese solution is used to supply manganese ions to raw water. The manganese solution is not particularly limited as long as it contains manganese as ions. Examples of the manganese solution include a manganese nitrate solution.

Below, the water treatment method using the water treatment system 2 of 2nd Embodiment is demonstrated.
First, the pump 50e is operated, and raw water stored in a raw water storage tank (not shown) is introduced into the accelerated oxidation tank 10 through the pipe 309. At this time, the manganese solution supplied from the manganese solution supply pipe 42 and the raw water are mixed, and the raw water is put into the accelerated oxidation tank 10 as a manganese ion-containing liquid to be treated.

  Next, in the accelerated oxidation tank 10, organic matter in the manganese ion-containing treated water is removed by promoting oxidation to generate manganese ion-containing treated water. The method for removing organic substances by promoting oxidation can be the same as in the case of the water treatment system 1.

  Next, the pump 50b is operated, the manganese ion-containing treated water generated in the accelerated oxidation tank 10 is introduced into the second packed tower 20b through the pipe 305, and the manganese ion-containing treated water and the manganese adsorbent particles 201b are supplied. The manganese ions are recovered by contacting them and adsorbing the manganese ions on the manganese adsorbent particles 201b. In the water treatment system 2, if water treatment is continued, manganese is accumulated in the manganese adsorbent particles 201b. Therefore, after performing a certain treatment, the manganese adsorbent particles 201b need to be replaced.

  Since the water treatment system 2 of the second embodiment described above uses a manganese solution for supplying manganese ions to the raw water, a certain amount of manganese ions is added to the raw water regardless of the quality of the raw water (pH, Eh). Can be supplied stably.

(Third embodiment)
FIG. 7 is a schematic diagram of a water treatment system according to the third embodiment.
In addition, in the following description, the same number is attached | subjected to the structure similar to the water treatment system 2 of 2nd Embodiment, and the overlapping description is abbreviate | omitted.

  The water treatment system 3 of the third embodiment shown in FIG. 7 is different from the water treatment system 2 in that the second packed tower 20b is filled with an ion exchange resin 202 as manganese adsorbent particles. The second packed tower 20b is provided with a regenerated liquid supply pipe 310 that supplies a regenerated liquid of the ion exchange resin, and a regenerated liquid discharge pipe 311 that discharges the regenerated liquid from the second packed tower 20b. An acid such as hydrochloric acid can be used as the regenerating solution.

Below, the water treatment method using the water treatment system 3 of 3rd Embodiment is demonstrated.
The raw water and the manganese solution are mixed in the pipe 309, and the raw water is introduced into the accelerated oxidation tank 10 as a manganese ion-containing liquid to be treated. Next, in the accelerated oxidation tank 10, organic matter in the manganese ion-containing treated water is removed by promoting oxidation to generate manganese ion-containing treated water. Next, manganese ion-containing treated water is charged into the second packed tower 20b, and manganese ions in the manganese ion-containing treated water are recovered in the second packed tower 20b. These operations can be the same as those of the water treatment system 2 of the second embodiment.

  In the water treatment system 3 of the third embodiment, manganese ions in the manganese ion-containing treated water are collected by being adsorbed on the ion exchange resin 202. In order to prevent the manganese ion adsorption ability of the ion exchange resin 202 from being lowered, it is necessary to recover the adsorption ability by collecting manganese ions from the ion exchange resin 202 after performing a certain treatment. For this reason, the regenerated liquid is periodically supplied from the regenerated liquid supply pipe 310 to the second packed column 20b, and it is necessary to take out the regenerated liquid from which the manganese ions have been recovered from the ion exchange resin 202 from the regenerated liquid discharge pipe 311. .

  According to the water treatment system 3 of the third embodiment described above, an ion exchange resin is used as the manganese adsorbent particles. Therefore, by repeatedly regenerating and using this ion exchange resin, manganese ions can be produced over a long period of time. It can be recovered stably.

  According to at least one embodiment described above, manganese ions are supplied to raw water containing organic matter to prepare manganese ion-containing treated water having a manganese ion concentration in the range of 0.01 mg / L to 10 mg / L. And X which is a pH value of the manganese ion-containing treated water and Y (unit: V) which is a redox potential value measured using a standard hydrogen electrode as a comparison electrode satisfies a predetermined formula As described above, supplying a pH adjuster and ozone to the manganese ion-containing treated water to remove organic substances in the manganese ion-containing treated water by accelerated oxidation to generate manganese ion-containing treated water; By having a step of recovering manganese ions in the ion-containing treated water, organic matter in the water is efficiently removed by accelerated oxidation. It is possible.

Hereinafter, embodiments will be described in detail using examples.
[Example 1]
Using the water treatment system 2 of the second embodiment shown in FIG. 6, the manganese ion concentration in the accelerated oxidation tank 10 and the catalytic effect on the accelerated oxidation were examined.
Raw water containing phenol at a concentration of 100 mg / l was introduced into the raw water storage tank. Next, the pump 50 e was operated to feed the raw water stored in the raw water storage tank into the accelerated oxidation tank 10 through the pipe 309. At this time, a manganese nitrate aqueous solution is supplied to the raw water from the manganese solution supply pipe 42, the manganese nitrate aqueous solution and the raw water are mixed, and the raw water is treated with manganese ions having a manganese ion concentration of 0.001 to 10 mg / l. Liquid.
While the manganese ion-containing liquid to be treated is stirred using the stirrer 101 in the accelerated oxidation tank 10, phosphoric acid and potassium dihydrogen phosphate are supplied as pH adjusting agents from the pH adjusting agent supply pipe 105, and manganese is added. The pH value (X) of the ion-containing liquid to be treated was adjusted to be in the range of 3.2 to 3.5. Further, an ozone-containing gas having an ozone concentration of 200 g / m ³ was supplied from the ozone supply pipe 104 so that the Eh value (Y) of the manganese ion-containing liquid to be treated was adjusted to 1.0 to 1.1V. The Eh value of the manganese ion-containing liquid to be treated was calculated from the oxidation-reduction potential measured using a silver chloride electrode as a comparative electrode, using the following conversion formula.

(Conversion formula)
Eh = E _{Ag / AgCl} + {206-0.7 (t-25)} / 1000
Eh: oxidation-reduction potential (V) when a standard hydrogen electrode is used as a reference electrode
E _{Ag / AgCl} : Redox potential (V) when a silver chloride electrode is used as a reference electrode
t: Temperature [° C]

In the accelerated oxidation tank 10, the manganese ion-containing treatment liquid was treated for 60 minutes to generate a manganese ion-containing treatment liquid.
Subsequently, the pump 50b and the three-way valves 60d and 60e were operated, and the manganese ion-containing treatment liquid in the accelerated oxidation tank 10 was charged into the second packed tower 20b. The 2nd packed tower 20b was filled with the filtration sand which coated manganese dioxide on the surface with an average particle diameter of about 1 mm as manganese adsorbent particle | grains 201b. At this time, hypochlorous acid is supplied from the oxidant supply pipe 40b and sodium hydroxide is supplied from the pH adjuster supply pipe 41b to the manganese ion-containing treatment liquid, and the pH value (X) of the manganese ion-containing treatment liquid is determined. 7.2, Eh value (Y) was adjusted to 0.8V.

  The treated water taken out from the second packed tower 20b via the pipe 307 had a manganese ion concentration of 0.1 mg / l or less.

(Evaluation)
The catalytic effect on accelerated oxidation was evaluated from the organic matter decomposition rate calculated from the following formula using TOC (Total Organic Carbon: total organic carbon). The TOC was measured using a TOC meter TOC-L manufactured by Shimadzu Corporation.
Organic matter decomposition rate (%) = (TOC of raw water−TOC of treated water) / TOC of raw water × 100

  FIG. 8 shows the relationship between the manganese ion concentration of the treated water containing manganese ions in the accelerated oxidation tank 10 and the organic matter decomposition rate. From the graph of FIG. 8, when the manganese ion concentration was 0.001 mg / l, the organic matter removal rate was about 60%, but when the manganese ion concentration was 0.01 to 10 mg / l, the organic matter decomposition rate was It exceeded 80%, and it turned out that the catalytic effect of manganese ion becomes high. In particular, when the manganese ion concentration is in the range of 0.05 to 0.2 mg / l, the organic matter removal rate exceeds 95%, and it was found that the catalytic effect of manganese ions is very high.

[Comparative Example 1]
When the decomposition test of phenol was performed under the same conditions as the manganese ion concentration of 2 mg / l in Example 1 except that the pH value (X) of manganese ion-containing treated water in the accelerated oxidation tank 10 was 7, 60 minutes The organic matter decomposition rate later was 55%, and there was almost no catalytic effect of manganese ions.

[Example 2]
Raw water containing phenol at a concentration of 100 mg / l was treated using the water treatment system 1 of the first embodiment shown in FIG. The first packed tower 20a and the second packed tower 20b were each filled with filter sand coated with manganese dioxide on the surface having an average particle diameter of about 1 mm used in Example 1.
Raw water adjusted to have a pH value (X) of 3.0 to 3.6 and an Eh value (Y) of 1.2 to 1.3 is supplied to the first packed column 20a, and manganese ion-containing treated water is supplied. Was prepared. The obtained manganese ion-containing treated water had a manganese ion concentration of 0.5 to 2 mg / l.
When the Eh value (Y) of the manganese ion-containing treated water was adjusted to 1.0 to 1.1 in the accelerated oxidation tank 10, the organic matter removal rate after 60 minutes was 80% or more.

[Example 3]
A test was conducted in the same manner as in Example 2 except that manganese ferrite having an average particle size of about 500 μm was used as the manganese compound particles 201a. As a result, manganese ions containing 0.01 to 0.19 mg / l manganese ions were contained. The water to be treated was obtained. When the Eh value (Y) of manganese ion-containing treated water was adjusted to 1.0 to 1.1 V in the accelerated oxidation tank 10, the organic matter removal rate after 60 minutes was 80% or more. .

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

1, 2, 3 ... Water treatment system, 10 ... Accelerated oxidation tank, 20a ... First packed tower (manganese ion supply device), 20b ... Second packed tower (manganese ion recovery device), 40a, 40c ... Ozone supply pipe, 40b, 40d ... Oxidant supply pipe, 41a, 41b, 41c, 41d ... pH adjuster supply pipe, 50a, 50b, 50c, 50d ... Pump, 60a, 60b, 60c, 60d, 60e, 60f ... Three-way valve, 103 ... Sensor, 201a ... Manganese compound particles, 201b ... Manganese adsorbent particles, 301, 302, 303, 304, 305, 306, 307, 308, 309 ... Piping, 310 ... Regeneration liquid supply pipe, 311 ... Regeneration liquid discharge pipe

Claims (7)

A water treatment method for removing organic matter in raw water containing organic matter by accelerated oxidation,
Supplying manganese ions to the raw water to prepare manganese ion-containing treated water having a manganese ion concentration in the range of 0.01 mg / L to 10 mg / L;
In order that X, which is the pH value of the manganese ion-containing treated water, and Y (unit: V), which is a redox potential value measured using a standard hydrogen electrode as a comparison electrode, satisfy the following formula: Supplying a pH adjuster and ozone to the manganese ion-containing treated water, removing organic matter in the manganese ion-containing treated water by accelerated oxidation, and generating manganese ion-containing treated water;
2 ≦ X ≦ 5
0.8 ≦ Y ≦ 1.5−0.08 × X
Recovering manganese ions in the manganese ion-containing treated water;
A water treatment method comprising: The step of preparing the manganese ion-containing treated water is a redox potential measured by supplying a pH adjusting agent and ozone to the raw water and measuring the raw water pH value X and a standard hydrogen electrode as a reference electrode. The value Y (unit: V) is adjusted so as to satisfy the following formula, the raw water and manganese compound particles are brought into contact with each other, and manganese ions are supplied to the raw water. The water treatment method as described.
2 ≦ X ≦ 5
1.5-0.08 × X <Y The step of recovering manganese ions in the manganese ion-containing treated water is performed by supplying a pH adjuster and ozone or hypochlorous acid to the manganese ion-containing treated water, wherein the pH value of the manganese ion-containing treated water is X And Y (unit: V), which is a redox potential value measured using a standard hydrogen electrode as a reference electrode, is adjusted so as to satisfy the following formula, and the manganese ion-containing treated water and manganese adsorbent particles: The water treatment method according to claim 1, wherein the manganese adsorbent particles are adsorbed with manganese ions.
5 <X ≦ 9
0.6 ≦ Y ≦ 1.5−0.08 × X The step of preparing the manganese ion-containing treated water is performed using a first packed tower packed with manganese compound particles, and the raw water is introduced into the first packed tower, and the raw water and the manganese compound particles are used. The step of contacting and supplying manganese ions to the raw water and collecting the manganese ions in the manganese ion-containing treated water is performed using a second packed tower packed with manganese adsorbent particles, and the manganese ions By containing the treated water into the second packed tower, bringing the treated water containing manganese ions into contact with the manganese adsorbent particles, and adsorbing manganese ions on the manganese adsorbent particles;
Thereafter, in the step of preparing the manganese ion-containing treated water, the raw water is introduced into the second packed tower, the raw water and the manganese adsorbent particles adsorbed with the manganese ions are brought into contact with each other, and the raw water The step of recovering manganese ions in the manganese ion-containing treated water is performed by supplying the manganese ion-containing treated water to the first packed tower, and the manganese ion-containing treated water and manganese The water treatment method of Claim 1 performed by making a compound particle contact and making a manganese ion adsorb | suck to the said manganese compound particle. A water treatment apparatus for removing organic matter in raw water containing organic matter by accelerated oxidation,
A raw water storage tank for storing raw water containing organic matter;
A manganese ion supply device for preparing manganese ion-containing treated water by supplying manganese ions to the raw water;
An accelerated oxidation tank that removes the organic matter in the manganese ion-containing treated water by accelerated oxidation to generate manganese ion-containing treated water;
And a manganese ion recovery device for recovering manganese ions from the manganese ion-containing treated water. A water treatment system for removing organic matter in raw water containing organic matter by accelerated oxidation,
A raw water storage tank for storing raw water containing organic matter;
A manganese ion supply device for preparing manganese ion-containing treated water by supplying manganese ions to the raw water;
An accelerated oxidation tank that removes the organic matter in the manganese ion-containing treated water by accelerated oxidation to generate manganese ion-containing treated water;
A manganese ion recovery device for recovering manganese ions from the manganese ion-containing treated water;
A control device,
The control device prepares manganese ion-containing treated water by charging raw water stored in the raw water storage tank into the manganese ion supply device and supplying manganese ions to the raw water with the manganese ion supply device. Next, the manganese ion-containing treated water is put into an accelerated oxidation tank, and the organic matter is removed by accelerated oxidation in the accelerated oxidation tank to produce manganese ion-containing treated water, and then the manganese ion-containing treated water A water treatment system in which manganese ions are collected by the manganese ion recovery device. The manganese ion supply device is a first packed tower packed with manganese compound particles;
The manganese ion recovery device is a second packed tower packed with manganese adsorbent particles,
The control device supplies manganese ions to the raw water by introducing the raw water stored in the raw water storage tank into the first packed tower, bringing the raw water and the manganese compound particles into contact with each other, and supplying manganese ions to the raw water. Preparing water to be treated, and then adding the water to be treated containing manganese ions to the accelerated oxidation tank, and removing the organic matter by accelerated oxidation in the accelerated oxidation tank to produce manganese ion-containing treated water; The manganese ion-containing treated water is charged into the second packed tower, the manganese ion-containing treated water and the manganese adsorbent particles are brought into contact with each other, and manganese ions are adsorbed on the manganese adsorbent particles. Collect
Thereafter, raw water stored in the raw water storage tank is introduced into the second packed tower, and the raw water and manganese adsorbent particles adsorbed with the manganese ions are brought into contact with each other to supply manganese ions to the raw water. The manganese ion-containing treated water is prepared, and then the manganese ion-containing treated water is put into an accelerated oxidation tank, and the organic matter is removed by accelerated oxidation in the accelerated oxidation tank to remove the manganese ion-containing treated water. And the manganese ion-containing treated water is introduced into the first packed tower, the manganese ion-containing treated water is brought into contact with the manganese compound particles, and the manganese compound particles are adsorbed with manganese ions. The water treatment system according to claim 6 which collects manganese ions.

Images