JP2020127383A - Culture method, culture apparatus, waste water treatment method, and waste water treatment apparatus - Google Patents

Abstract

A culture method and apparatus, and a wastewater treatment method and apparatus capable of improving biological activity are provided. A method for culturing cells using a medium, wherein the concentration of at least one of Mn, Mo and Co among metal elements contained in the medium is 0.001 mg/L or less. The method. Also, a metal element removal unit 14 for removing metal elements from the culture medium, and a metal element addition unit 16 for adding metal elements not containing Mn, Mo and Co to the culture medium from which the metal elements have been removed by the metal element removal unit 14. and a culturing unit 18 for culturing cells using a medium to which metal elements not containing Mn, Mo and Co are added in the metal element adding unit 16 . Furthermore, it is a wastewater treatment method and apparatus for adding metal elements not containing Mn, Mo and Co to wastewater discharged from the manufacturing facility 46 using water from which metal elements have been removed, and treating the wastewater. [Selection drawing] Fig. 4

Description

The present invention relates to a culture method, a culture device, a wastewater treatment method and a wastewater treatment device, and in particular, by identifying a metal element in a culture medium or wastewater, it is possible to improve the number of cells and various activities of the culture. The present invention relates to a method, a culture device, a wastewater treatment method, and a wastewater treatment device.

In a factory that manufactures semiconductors, if metal remains on the surface of the semiconductor, it adversely affects the product. Therefore, water from which the metal element has been removed is used. Drugs based on NH ₄ F) have been used. Therefore, the wastewater discharged from such equipment does not contain the metal elements necessary to maintain the bacteria used for wastewater treatment, so add metal elements before performing wastewater treatment. Was being done.

For example, the following Non-Patent Document 1 describes adding Mn, Mo, Co, Fe, Se, Ni, Cu, Zn and B as metal elements.

Van der Graaf et al., Microbiology 142:p.2187-2196 (1996).

When the metal element is insufficient in the medium or the waste water, the activity can be improved by adding the metal element. However, detailed conditions for which metal contained in the medium or the waste water to improve the activity have not been examined. Further, conventionally, it has been known that the activity is improved by adding a metal component, but it has not been examined that the activity is improved by limiting or eliminating the metal component.

The present invention has been made in view of such circumstances, by limiting the metal element contained in the medium or wastewater, a culture method, a culture device, a wastewater treatment method and wastewater that can improve biological activity. An object is to provide a processing device.

In order to achieve the object of the present invention, the culturing method according to the present invention is a cell culturing method for culturing cells using a medium, wherein, among metal elements contained in the medium, Mn, Mo and Co At least one concentration is 0.001 mg/L or less.

In order to achieve the object of the present invention, the culturing apparatus according to the present invention provides a metal element removing unit for removing a metal element from a medium, and a medium from which the metal element has been removed by the metal element removing unit, Mn, Mo and Co. And a culture unit for culturing cells using a medium to which the metal element not containing Mn, Mo and Co is added in the metal element addition unit.

In order to achieve the object of the present invention, the wastewater treatment method according to the present invention is a wastewater treatment method of wastewater discharged from a manufacturing process using water from which a metal element has been removed, wherein the wastewater contains Mn, Mo and The method includes an addition step of adding a metal element not containing Co and a wastewater treatment step of treating wastewater of wastewater using bacteria.

In order to achieve the object of the present invention, a wastewater treatment device according to the present invention is a wastewater treatment device for wastewater discharged from a manufacturing facility using water from which metal elements have been removed, and the wastewater contains Mn, Mo and Co. A metal element addition section for adding a metal element not containing, and a wastewater treatment section for treating wastewater of wastewater to which a metal element not containing Mn, Mo and Co is added in the metal element addition section using bacteria. Prepare

According to the culturing method and the culturing apparatus of the present invention, among the metal elements contained in the medium, the concentration of at least one of Mn, Mo, and Co is set to a low concentration of 0.001 mg/L or less, whereby the cell number is Can be improved. Further, according to the wastewater treatment method and the wastewater treatment apparatus of the present invention, the biological activity in the wastewater treatment can be improved by using the wastewater to which the metal element containing no Mn, Mo and Co is added.

It is an apparatus flow which shows a culture apparatus. It is an apparatus flow which shows the apparatus containing a wastewater treatment apparatus. It is a figure which shows the apparatus used in Example 1 to Example 5. FIG. 5 is a diagram showing the results of Example 1. 5 is a diagram showing the results of Example 2. FIG. FIG. 8 is a diagram showing the results of Example 4. 9 is a diagram showing the results of Example 5. FIG. 9 is a diagram showing the results of Example 5. FIG.

Hereinafter, a culture method, a culture apparatus, a wastewater treatment method, and a wastewater treatment apparatus according to the present invention will be described with reference to the accompanying drawings. In addition, in this specification, "-" is used by the meaning including the numerical value described before and after that as a lower limit and an upper limit.

[Culturing method]
The culture method of the present embodiment is a culture method in which the concentration of at least one of Mn, Mo, and Co among the metal elements contained in the medium is 0.001 mg/L or less.

<Medium preparation method>
In the medium of the present embodiment, at least one element of Mn, Mo and Co in the medium to be supplied is limited to 0.001 mg/L or less and culturing is performed. As a method for limiting at least one element of Mn, Mo and Co to 0.001 mg/L or less, an adsorbent that selectively adsorbs Mn, Mo and Co can be used.

Further, it is possible to produce ultrapure water from which all metal elements have been removed, and to add necessary metal elements to this ultrapure water. At this time, one or more of Mn, Mo, and Co are excluded from the added metal element. As a method for producing ultrapure water, distillation, an ion exchange resin, a reverse osmosis membrane, or the like can be used to remove the metal element for production. The ultrapure water to be produced preferably has an electric conductivity of 17 MΩ·cm or more and 0.058 μS/cm or less. By producing the culture medium by this method, the required addition amount of the metal element can be controlled.

Elements such as Fe, Cu, and Zn that are added as metal elements necessary for culturing are preferably added because the cells cannot grow unless they are contained in the medium. In addition, Al, Cr, Na, K, Mg etc. are mentioned as a metal element added. The metal element to be added is costly when added in a large amount, and may possibly inhibit the activity. Further, when the medium is waste water, there is a concern about environmental pollution at the destination where the treated water after the waste water treatment is discharged. Therefore, the amount of the metal element to be added needs to be a limit amount capable of maintaining the performance, and is preferably 0.005 mg/L or more, and more preferably 0.02 mg/L or more.

<Culture method and culture period>
The culture is preferably performed by continuous culture in which the medium is continuously supplied. The culture period is not particularly limited, but it is 1 week or longer, more preferably 1 month or longer. The time it takes for the effect to occur depends on the time it takes for the cell to divide. That is, since the metal element maintained in the cell is inherited by the dividing cell, if the cell that divides quickly has a large amount of the required metal element, the effect can be obtained quickly. On the other hand, in a long-lived cell, once taken up, it is maintained in the cell, so it takes time for the effect to occur. Therefore, for cells having a long lifespan, high effects can be obtained by culturing for a long period of time. In addition, batch culture may be performed, or short-term culture may be performed.

<Cell>
The cells cultured by the culture method of the present embodiment are mainly microbial cells, but can also be applied to animal cells. In particular, when nitrogen waste water is used as the medium, nitrifying bacteria or anammox bacteria can be used.

Bacteria are preferably held in a culture tank (culturing section) while being immobilized on a carrier. As a method of immobilizing bacteria, there are a method of adhering and immobilizing to a carrier surface to form an immobilizing carrier, and a method of including and immobilizing bacteria in the carrier to immobilize the entrapping immobilizing carrier. By using the entrapping immobilization pellets, cells can be maintained inside the pellets, and thus cells (bacteria) can be prevented from flowing out even after long-term culture.

Examples of the carrier include gel carriers such as polyvinyl alcohol, alginic acid, polyethylene glycol and acrylamide, plastic carriers such as cellulose, polyester, polypropylene, vinyl chloride and polyurethane, and inorganic carriers such as activated carbon, diatomaceous earth and zeolite. .. The form of the carrier is, for example, a fluidized bed using a floating carrier molded in an appropriate shape such as a sphere, a cylinder, a cylinder, a cube, or a rectangular parallelepiped, a sponge-like, non-woven fabric-like, hollow fiber-like carrier filter medium having a honeycomb shape or a wavy shape. It may be a fixed bed arranged in a grid pattern, a fiber pattern, a chrysanthemum pattern, or the like. For the fluidized bed, the size of the floating carrier is preferably in the range of 1 mm or more and 10 mm or less, and the filling rate thereof is preferably in the range of 10% by volume or more and 40% by volume or less with respect to the capacity of the culture tank. On the other hand, with respect to the fixed bed, the filling rate is preferably in the range of 10% by volume or more and 50% by volume or less in apparent occupied volume with respect to the capacity of the culture tank, and the porosity thereof is preferably 80% or more. ..

When the cells are not immobilized on a carrier, a method for separating the cultured cells includes membrane separation using an MBR (Membrane Bio Reactor) reactor. This can prevent the cultured cells from flowing out of the culture tank. The material of the film may be PVDF, PVC, PE or the like, but is not particularly limited. The pore size of the membrane is appropriately selected according to the size of cells to be separated.

<Inference of cause of effect>
In recent years, it has been known that in the case of culturing nitrifying bacteria, the nitrifying bacteria produce hydrogen peroxide, so that the activity is reduced and the isolated culture cannot be performed. The produced hydrogen peroxide is decomposed by an enzyme that decomposes hydrogen peroxide, such as catalase possessed by other bacteria. Therefore, if the activity of producing hydrogen peroxide can be reduced, it is possible to reduce the poisons that nitrifying bacteria produce themselves. Since the hydrogen peroxide concentration in cells can be lowered by lowering the hydrogen peroxide production activity, it can be expected that the activity is significantly increased.

Although the above reaction path has not been specified, the elements of Mo, Mn and Co contribute to these reactions, and the concentration of Mo, Mn and Co is lowered to lower the hydrogen peroxide production activity. It is presumed that The effects of the present invention can be obtained by setting the concentrations of Mo, Mn, and Co to 0.001 mg/L or less. On the other hand, Fe is used for ammonia oxidase, and without Fe, nitrifying bacteria cannot grow in the first place. From these facts, it is considered that the activity will be improved if the metal elements necessary for the growth can be supplied and the poisons of the active oxygen species such as hydrogen peroxide can be removed.

<Incubator>
FIG. 1 is an apparatus flow showing the culture apparatus of this embodiment. The culture device includes a metal element removal unit 14, a metal element addition unit 16, and a culture unit 18. The culture medium supplied from the culture medium supply pipe 12 is processed by the metal element removal unit 14 and the metal element addition unit 16 and supplied to the culture unit 18. In the culture unit 18, the cells put into the culture unit 18 are cultured. The medium used in the culture unit 18 is discharged from the medium discharge pipe 20.

The metal element removing unit 14 removes metal elements from the medium supplied from the medium supply pipe 12. Examples of the metal element removing unit 14 include a distillation device, an ion exchange resin, and a reverse osmosis membrane.

The metal element addition unit 16 adds a metal element that does not contain Mn, Mo and Co. Examples of the metal element to be added include Fe, Cu, Zn, Al, Cr, Na, K and Mg. The device used for adding the metal element is not particularly limited. In addition, in this specification, "Mn, Mo, and Co are not included" means that Mn, Mo, and Co are not positively added, and does not include contamination. Specifically, it means 0.001 mg/L or less.

The culturing unit 18 is a metal element adding unit 16 and cultures cells using a medium to which a metal element containing no Mn, Mo, and Co is added. The culture unit 18 may be a culture tank. The culturing unit 18 includes a pH controller and a temperature adjusting unit, and the pH and temperature in the culturing unit 18 are appropriately adjusted to optimum conditions for culturing. The culture medium 18 to which the metal element is added is continuously supplied to the culture unit 18 by the metal element addition unit 16, and the cells are cultured. The cells to be introduced into the culture unit 18 may be cells as they are, or may be an immobilization carrier in which the cells are immobilized on a carrier or an entrapping immobilization carrier.

<Wastewater treatment method and wastewater treatment device>
The culturing method and culturing apparatus described above can be applied to a wastewater treatment method and a wastewater treatment apparatus. FIG. 2 is an apparatus flow showing an apparatus including the wastewater treatment apparatus of this embodiment. The apparatus shown in FIG. 2 includes a metal element removal unit 44, a manufacturing facility 46, a metal element addition unit 48, and a wastewater treatment unit 50. The wastewater treatment device of this embodiment corresponds to the metal element addition unit 48 and the wastewater treatment unit 50.

The metal element removing unit 44 removes the metal element from the raw water supplied from the raw water pipe 42. Examples of the metal element removing unit 44 include a distillation device, an ion exchange resin, a reverse osmosis membrane, and the like.

The water from which the metal element has been removed by the metal element removal unit 44 is sent to the manufacturing facility 46 and used for manufacturing (manufacturing process). The manufacturing facility 46 is a facility that uses water from which metal elements have been removed, and may be, for example, a facility that performs a semiconductor etching process. A chemical containing ammonium fluoride as a main component is used as the etching liquid, and nitrogen wastewater is discharged as wastewater from the equipment for performing the etching process.

The metal element addition unit 48 adds a metal element that does not contain Mn, Mo, and Co (metal element addition step). Examples of the metal element to be added include Fe, Cu, Zn, Al, Cr, Na, K and Mg. The device used for adding the metal element is not particularly limited.

The wastewater treatment unit 50 treats the wastewater, to which the metal element containing no Mn, Mo, and Co is added by the metal element addition unit 48, with bacteria (wastewater treatment step). Examples of the wastewater treatment unit 50 include a nitrification tank and a denitrification tank. The wastewater treatment unit 50 includes a pH controller and temperature adjusting means, and the pH and temperature in the wastewater treatment unit 50 are appropriately adjusted to optimum conditions for wastewater treatment. To the wastewater treatment unit 50, the metal element addition unit 48 continuously supplies the wastewater to which the metal element is added, and the wastewater treatment is performed. As the bacterium to be put into the wastewater treatment unit 50, the bacterium may be put as it is, or may be an immobilization carrier in which the bacterium is immobilized on a carrier or an entrapping immobilization carrier. Further, as the bacteria, nitrifying bacteria or anammox bacteria can be used when the drainage is nitrogen drainage. Bacteria can be appropriately selected according to the components contained in the wastewater to be treated. The treated water treated by the wastewater treatment unit 50 is discharged from the treated water discharge pipe 52.

According to the wastewater treatment method and the wastewater treatment apparatus of the present embodiment, the concentration of at least one of Mn, Mo, and Co contained in the wastewater can be lowered, so that the biological activity of bacteria can be improved and the wastewater. The processing capacity can be improved. Further, since it is used for drainage from a manufacturing facility using water from which the metal element has been removed, it is not necessary to remove the metal element from the drainage, and work can be made efficient.

Further, the culture method, the culture apparatus, the wastewater treatment method and the wastewater treatment apparatus of the present embodiment can be preferably used in the partial nitrite type nitrification step of oxidizing half of nitrite, which is the pretreatment step of the anammox reaction. .. In nitrogen wastewater treatment using the anammox reaction, maintaining activity in the nitrification process is extremely important. The anammox reaction is a reaction for converting ammonia and nitrous acid into nitrogen gas. Since only ammonia is usually contained in the waste water, a step of oxidizing half of the ammonia to nitrous acid is necessary.

As will be shown in Examples described later, it can be seen that ammonia and nitrous acid in the treated water are contained in approximately equal amounts, and a half amount of nitrification is completed. In order to maintain this performance, addition of a metal element is essential. In the anammox reaction, the ratio of ammonia and nitrous acid shifts, and if either one becomes too large, it will remain in the treated water and the performance will deteriorate, so half of the amount, which is the pretreatment step of the anammox reaction, is oxidized to nitrous acid. In the partial nitrite type nitrification process, it is particularly important to maintain the nitrification performance.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to this embodiment, and can be appropriately modified without departing from the spirit of the present invention.

(Example 1) <Mn restriction test>
FIG. 3 shows a diagram of the experimental apparatus 100 used. An experiment was conducted using a cylindrical reaction tank 110 having a volume of 1.44 L. An air supply pipe 102 made of glass is attached so that air can be supplied, the air is adjusted using a flow meter 104, and then the air is supplied to the reaction tank 110 and aerated, and the carrier 106 in the reaction tank 110 flows and oxygen is supplied. I went. The aeration amount was adjusted using the flow meter 104. The raw water was supplied from the raw water storage tank 108 through a raw water supply pipe 114 by using a pump (perista pump) 112. To adjust the pH in the reaction tank 110, the pH sensor 116 measures the pH in the reaction tank 110, the pH controller 118 is used to control the pump 120, and the supply amount of the 1N NaOH solution in the alkaline solution storage tank 122 is controlled. did. The 1N NaOH solution was supplied into the reaction tank 110 through the alkali solution supply pipe 124 and adjusted to have a pH of 7.5.

≪Basic drainage≫
In the experiment, first, the startup operation was performed. That is, after starting up (culturing) without restricting metal elements, ammonia nitrogen and nitrite nitrogen in the treated water became almost equal in quantity, and after reaching a steady state, a restriction test was conducted.

The basic wastewater (basic medium) is shown below. As raw water (test wastewater), the ammonia synthesis wastewater shown in Table 1 was adjusted to ultrapure water, and then the metal elements shown in Table 2 and the Fe solution shown in Table 3 were added to the wastewater to be 1/1000. ..

<<Mn limited test drainage>>
By eliminating the Mn ^2+, since the nitrite-type nitrification reaction is examined whether activation, limiting the Mn ²⁺ addition concentration, and evaluated the nitrification performance. The metal element addition conditions are shown in Tables 2 to 4. This metal element solution was added to the wastewater so that the solution became 1/1000.

≪Test carrier≫
Activated sludge containing nitrifying bacteria was entrapped and immobilized with a polyethylene glycol-based gel and shaped into spheres of about 4 mm.

To prepare the carrier, the mixed solution [1] shown in Table 5 (sodium alginate, polyethylene glycol (PEG), N,N,N',N'-tetramethylethylenediamine (TMED), pure water, activated sludge) was used. The mixture solution [2] shown in Table 6 (CaCl ₂ .2H ₂ O, potassium peroxodisulfate (KPS)) was added dropwise to form a film with alginic acid to form a spherical shape, and then PEG was polymerized to nitrify. The bacteria were entrapped and immobilized.

FIG. 4 shows the results of the changes with time of ammonia and nitrous acid in the treated water. Until the 35th day, basic wastewater was supplied and treated, and after the 35th day, Mn-limited test wastewater was supplied and treated. It was confirmed that the nitrite concentration in the treated water exhibiting nitrification activity was increased, and the nitrite concentration on day 35 was 232 mg/L, but it increased to 280 mg/L on day 64. From these results, it was confirmed that nitrification activity was increased by removing Mn.

(Example 2) <Mo restriction test>
The same test was performed by changing the conditions for adding the metal element in Example 1. The start-up operation was performed using the basic drainage of Example 1, and after reaching a steady state, the metal element concentrates shown in Table 2 were changed to the metal element concentrates shown in Table 7 and tests were conducted. The concentrated metal element solutions in Table 7 were added so as to be 1/1000.

Results are shown in FIG. In Example 2, the basic wastewater was supplied and treated until the 65th day, and the Mo-limited test wastewater was supplied and treated after the 65th day. The nitrite nitrogen concentration of the treated water was 278 mg/L on the 65th day, but increased to 348 mg/L on the 85th day. It was confirmed that the nitrification activity was increased by removing Mo.

(Example 3) <Co restriction test>
The same test was performed by changing the conditions for adding the metal element in Example 1. The start-up operation was performed using the basic drainage of Example 1, and after reaching a steady state, the Co element limiting test was performed by switching the metal element concentrates shown in Table 2 to the metal element concentrates shown in Table 8. It was The concentrated metal element solution in Table 8 was added to be 1/1000.

As a result, it was confirmed that the nitrite concentration of the treated water tended to increase from 249 mg/L to 289 mg/L.

(Example 4) <Ni restriction test>
The same test was performed by changing the conditions for adding the metal element in Example 1. The start-up operation was performed using the basic drainage of Example 1, and after reaching a steady state, the metal element concentrated solution shown in Table 2 was switched to the metal element concentrated solution shown in Table 9 to perform the Ni restriction test. It was The concentrated metal element solution in Table 9 was added to be 1/1000.

Results are shown in FIG. Regarding Example 4 in which only Ni was restricted, the NO ₂ concentration in the treated water was extremely stable, and the effect of activity due to the restriction of Ni did not appear.

(Example 5) <Zn restriction test>
In order to confirm the influence of Zn, Zn was limited by switching the metal element concentrated solution shown in Table 2 to the metal element concentrated solution shown in Table 10. The concentrated solution was added so as to be 1/1000. In addition, after checking the limitation, when looking at the recovery performance, a Zn solution was appropriately added so as to have a predetermined concentration.

The daily changes in the quality of treated water are shown in FIGS. 7 and 8. Further, _NO ² for ^{Zn 2+} concentration in the waste water in Table 11 - shows the -N concentration. _NO ² limits prior to treatment water - -N concentration was averaged 250MgL ^-1, but after 21 days when stopping the ^{Zn 2+} added was reduced to 175mgL ^-1. From these results, it was shown that Zn ²⁺ is an essential metal element in the nitrification reaction (FIG. 7).

Next, in order to examine the addition amount of the metal element, Zn was added and a recovery test was performed. Even when the Zn concentration 0.05 mg / L was added, the performance did not recover, then when the ^{Zn 2+} doping concentration and 0.02MgL ^-1, the treated water _NO ² - -N concentration was raised to 257MgL ^-1 , The activity was completely restored (Fig. 8).

From these facts, in order to confirm the limiting effect of the metal element, it is preferable to set the concentration of each element to 0.02 mg/L or less, more preferably 0.005 mg/L or less, and further preferably It is preferable to limit the amount to 0.001 mg/L or less.

12... Medium supply pipe, 14... Metal element removal part, 16... Metal element addition part, 18... Culture part, 20... Medium discharge pipe, 42... Raw water pipe, 44... Metal element removal part, 46... Manufacturing equipment, 50... Waste water treatment part, 52... Treated water discharge pipe, 100... Experimental device, 102... Air supply pipe, 104... Flow meter, 106... Carrier, 108... Raw water storage tank, 110... Reaction tank, 112... Pump, 114... Raw water supply Pipe, 116... pH sensor, 118... pH controller, 120... Pump, 122..., 124... Alkaline solution storage tank, 126... Alkaline solution supply pipe

Claims (18)

A method of culturing cells, which comprises culturing cells using a medium,
Among the metallic elements contained in the medium, the culture method wherein the concentration of at least one of Mn, Mo and Co is 0.001 mg/L or less. The culture method according to claim 1, wherein the medium is continuously supplied. The culture method according to claim 1 or 2, wherein the medium is a medium obtained by adding metal elements other than Mn, Mo, and Co to water from which metal elements have been removed. The culture method according to any one of claims 1 to 3, wherein the cells are nitrifying bacteria or anammox bacteria. The culture method according to claim 4, wherein the medium is nitrogen drainage. The culture method according to any one of claims 1 to 5, wherein the cells are immobilized on a carrier or entrapped in a carrier, or maintained in the medium by membrane separation. A metal element removing section for removing metal elements from the medium,
In the medium from which the metal element has been removed by the metal element removal unit, a metal element addition unit that adds a metal element that does not contain Mn, Mo and Co,
And a culture unit for culturing cells using a medium to which the metal element containing no Mn, Mo, and Co is added in the metal element addition unit. The culture device according to claim 7, wherein the cells are nitrifying bacteria or anammox bacteria. The culture device according to claim 8, wherein the medium is nitrogen drainage. The culture device according to any one of claims 7 to 9, wherein the cells are immobilized on a carrier or entrapped in a carrier, or maintained in the medium by membrane separation. A wastewater treatment method for wastewater discharged from a manufacturing process using water from which metal elements have been removed,
An adding step of adding a metal element containing no Mn, Mo and Co to the waste water;
A wastewater treatment step of treating the wastewater of the wastewater with bacteria. The wastewater treatment method according to claim 11, wherein the bacterium is a nitrifying bacterium or an anammox bacterium. The wastewater treatment method according to claim 12, wherein the wastewater is nitrogen wastewater. The wastewater treatment method according to any one of claims 11 to 13, wherein the bacterium is immobilized on a carrier or entrapped in a carrier, or is maintained in the wastewater by membrane separation. A wastewater treatment device for wastewater discharged from a manufacturing facility using water from which metal elements have been removed,
A metal element addition part for adding a metal element not containing Mn, Mo and Co to the waste water,
A wastewater treatment apparatus comprising: a wastewater treatment unit that uses wastewater to treat wastewater to which the metal element containing no Mn, Mo, and Co is added in the metal element addition unit using bacteria. The wastewater treatment apparatus according to claim 15, wherein the bacteria are nitrifying bacteria or anammox bacteria. The wastewater treatment device according to claim 16, wherein the wastewater is nitrogen wastewater. The wastewater treatment apparatus according to any one of claims 15 to 17, wherein the bacterium is immobilized on a carrier or entrapped and immobilized, or is maintained in the wastewater by membrane separation.