JP2023113427A - Water treatment equipment and water treatment method - Google Patents

Abstract

To provide water treatment equipment and a water treatment method capable of efficiently removing organic matter from wastewater and obtaining good water quality through an anaerobic treatment method.SOLUTION: A water treatment equipment 100 has a water treatment structure 10 with an anode 12 that contacts treated water 30 inhabited by anaerobic microorganisms 3 with facultative and absolute anaerobes and to which the anaerobic microorganisms attach, and a cathode 11 that is electrically connected to the anode and that contacts gas phase 40 containing oxygen and treated water. The water treatment equipment is further provided with an aeration device 50 that intermittently aerates the treated water with oxygen-containing gas. The aeration device alternately repeats the state of performing aeration and the state of stopping aeration, and in the state of performing aeration, the gas is brought into contact with anaerobic microorganisms. The water treatment method is a method using the water treatment structure, and alternately repeats an aeration state in which the gas is brought into contact with anaerobic microorganisms by aerating the treated water with oxygen-containing gas, and an aeration stop state in which the aeration of the gas is stopped.SELECTED DRAWING: Figure 2

Description

The present invention relates to a water treatment device and a water treatment method.

BACKGROUND ART Conventionally, various water treatment methods have been provided to remove organic matter contained in waste water. Specifically, water treatment methods such as an activated sludge method using aerobic respiration of microorganisms and an anaerobic treatment method using anaerobic respiration of microorganisms are provided.

In the activated sludge method, sludge containing microorganisms (activated sludge) and wastewater are mixed in a bioreactor, and the air necessary for the microorganisms to oxidatively decompose the organic matter in the wastewater is sent into the bioreactor and agitated. and purify wastewater. However, the activated sludge process requires a huge amount of electric power for aeration of the bioreactor. In addition, as a result of the active metabolism of microorganisms through oxygen respiration, a large amount of sludge (dead microorganisms), which is industrial waste, is generated.

On the other hand, since the anaerobic treatment method does not require aeration, it is possible to greatly reduce the amount of electric power required compared to the activated sludge method. In addition, since the free energy acquired by microorganisms is small, the amount of sludge generated is reduced. A microbial fuel cell described in Patent Document 1 is disclosed as a water treatment apparatus using such an anaerobic treatment method.

Microbial fuel cells have a negative electrode carrying microorganisms and a positive electrode in contact with an oxygen-containing gas phase and wastewater. Then, waste water containing organic substances and the like is supplied to the negative electrode, and a gas containing oxygen is supplied to the positive electrode. The negative and positive electrodes form a closed circuit by connecting them together through a load circuit. At the negative electrode, hydrogen ions and electrons are produced from the wastewater by catalytic action of microorganisms. Then, the generated hydrogen ions move to the positive electrode, and the electrons move to the positive electrode through the load circuit. The hydrogen ions and electrons transferred from the negative electrode combine with oxygen at the positive electrode and are consumed as water. At that time, the electrical energy flowing in the closed circuit can be recovered.

In Patent Literature 1, a negative electrode that is immersed in an organic substrate to support anaerobic microorganisms, an outer shell formed of an ion-permeable diaphragm, and an inlet/outlet hole are enclosed together with an electrolytic solution in a sealed hollow cassette. A microbial fuel cell is disclosed that includes a positive electrode that is inserted into an organic substrate by means of a In the microbial fuel cell, electricity is taken out through a circuit electrically connecting the negative electrode and the positive electrode while supplying oxygen into the cassette through the inlet/outlet holes.

JP-A-2009-93861

Conventional water treatment equipment using microbial fuel cells can also treat organic matter in wastewater to some extent. However, there is a demand for a water treatment apparatus capable of more efficiently treating organic matter in wastewater and obtaining good water quality.

The present invention has been made in view of such problems of the prior art. It is another object of the present invention to provide a water treatment apparatus and a water treatment method capable of efficiently removing organic substances in wastewater by an anaerobic treatment method to obtain good water quality.

In order to solve the above problems, a water treatment apparatus according to an aspect of the present invention contacts water to be treated in which anaerobic microorganisms having facultative anaerobes and obligate anaerobes live, and the anaerobic microorganisms and a positive electrode electrically connected to the negative electrode and in contact with the gas phase containing oxygen and the water to be treated. The water treatment apparatus further includes an aeration device that intermittently aerates the water to be treated with gas containing oxygen. The aeration device alternates between running and stopping aeration, and in the running state of aeration the gas containing oxygen is brought into contact with the anaerobic microorganisms.

The water treatment apparatus may further include a treatment tank that holds therein the water treatment structure, the water to be treated, and at least part of the aerator.

In the water treatment apparatus, it is preferable that the facultative anaerobes remain in the water to be treated and the obligate anaerobes are removed from the water to be treated by contacting the anaerobic microorganisms with a gas containing oxygen.

In the water treatment device, the aeration device may alternately repeat the aeration state and stop state at regular intervals.

In the water treatment system, the aeration on-state time can be 10-20 minutes and the aeration off-state time can be 40 minutes to 3 hours.

In the water treatment device, the positive electrode may be attached with aerobic microorganisms or may carry an oxygen reduction catalyst.

In the water treatment structure, the negative electrode and the positive electrode are integrated, and the shape of the water treatment structure may be plate-like, rod-like, or string-like.

A water treatment method according to an aspect of the present invention is in contact with water to be treated in which anaerobic microorganisms having facultative anaerobes and obligate anaerobes live, and to which the anaerobic microorganisms adhere; and a positive electrode in contact with a vapor phase containing oxygen and the water to be treated. In the water treatment method, by aerating a gas containing oxygen to the water to be treated, an aeration execution state in which the gas is brought into contact with anaerobic microorganisms and an aeration stop state in which the aeration of the gas is stopped are alternately performed. repeat.

Advantageous Effects of Invention According to the present invention, it is possible to provide a water treatment apparatus and a water treatment method capable of efficiently removing organic substances in wastewater by an anaerobic treatment method and obtaining good water quality.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows an example of the water treatment apparatus which concerns on 1st embodiment. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1; FIG. 2 is a cross-sectional view taken along line BB in FIG. 1; FIG. 4 is a cross-sectional view for explaining a mechanism for purifying water to be treated by the water treatment structure; FIG. 4 is a cross-sectional view for explaining a mechanism for purifying water to be treated by the water treatment structure; It is a perspective view which shows an example of the water treatment apparatus which concerns on 2nd embodiment. FIG. 6 is an exploded perspective view showing a laminate formed by laminating a positive electrode, a spacer member, and a plate member in the water treatment device according to the second embodiment. FIG. 7 is a cross-sectional view taken along line CC in FIG. 6; 4 is a photograph showing a state before treating water to be treated in the water treatment structure of Example 1. FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the water-treatment system of an Example and a comparative example. (a) is a photograph showing the state of the negative electrode surface after treating the water to be treated in the water treatment structure of Example 1. FIG. (b) is a photograph showing the state of the negative electrode surface after treating the water to be treated in the water treatment structure of Example 2. FIG. (c) is a photograph showing the state of the negative electrode surface after treating the water to be treated in the water treatment structure of Comparative Example 1. FIG.

Hereinafter, the water treatment apparatus and the water treatment method according to this embodiment will be described in detail with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from the actual ratios.

[First embodiment]
As shown in FIGS. 1 to 3, the water treatment apparatus 100 according to the present embodiment contains a water treatment structure 10, the water treatment structure 10, and water to be treated 30 to be purified by the water treatment structure 10. and a processing tank 20 for holding the same. The water treatment device 100 further includes an aeration device 50 for aerating gas containing oxygen to the water 30 to be treated.

(water treatment structure)
In this embodiment, the water treatment structure 10 comprises an electrical conductor 1 . As shown in FIGS. 1 to 3, the conductor 1 is made of a conductive material and is a substantially rectangular parallelepiped flat plate member.

The water treatment structure 10 has a site where an oxygen reduction reaction for reducing oxygen in the gas phase 40 occurs, and a site where an organic matter oxidation reaction for generating hydrogen ions and electrons by oxidizing organic matter in the water 30 to be treated occurs. have. Specifically, in the water treatment structure 10, the site where the oxygen reduction reaction occurs is the upper part (positive electrode 11) in contact with the gas phase 40 and the water to be treated 30, and the site where the organic substance oxidation reaction occurs is the It is the lower part (negative electrode 12 ) in contact with the treated water 30 . Thus, in the water treatment structure 10, the positive electrode 11 and the negative electrode 12 are integrated.

The conductor 1 constituting the water treatment structure 10 has an internal space for hydrogen ions (H ⁺ ) to move between the positive electrode 11 in which oxygen reduction reaction occurs and the negative electrode 12 in which organic material oxidation reaction occurs. there is The presence of a continuous space inside the conductor 1 allows hydrogen ions generated in the negative electrode 12 to move to the positive electrode 11 through the internal space, as will be described later.

The material of the conductor 1 is not particularly limited as long as it can ensure conductivity, but at least one selected from the group consisting of conductive metals, carbon materials and conductive polymer materials can be used, for example. As the conductive metal, for example, at least one selected from the group consisting of aluminum, copper, stainless steel, nickel and titanium can be used. As the carbon material, for example, at least one selected from the group consisting of carbon paper, carbon felt, carbon cloth and graphite sheet can be used. At least one selected from the group consisting of polyacetylene, polythiophene, polyaniline, poly(p-phenylene vinylene), polypyrrole and poly(p-phenylene sulfide) can be used as the conductive polymer material.

As described above, since the conductor 1 has an internal space between the positive electrode 11 and the negative electrode 12 for hydrogen ions to move, it is preferable to have a continuous space from the negative electrode 12 toward the positive electrode 11 . In order to secure such an internal space, the conductor 1 preferably comprises a porous conductive sheet. Moreover, the conductor 1 is more preferably made of a porous conductive sheet. Since such a porous conductive sheet has a large number of pores inside, hydrogen ions can easily move.

The conductor 1 preferably includes at least one of a woven conductive sheet and a nonwoven conductive sheet. A woven fabric-like conductive sheet and a non-woven fabric-like conductive sheet have a large number of pores, and therefore can facilitate the movement of hydrogen ions. Also, the conductor 1 may be a metal plate having a plurality of through holes from the negative electrode 12 to the positive electrode 11 .

The conductor 1 more preferably comprises a non-woven conductive sheet, particularly preferably a non-woven conductive sheet. Since the thickness and porosity of the non-woven fabric can be easily changed, a configuration in which anaerobic microorganisms adhere to the negative electrode 12 of the conductor 1 and the positive electrode 11 carries an oxygen reduction catalyst or aerobic microorganisms can be easily obtained, as described later. be able to. The pore diameter of the space in the conductor 1 is not particularly limited as long as hydrogen ions can move from the negative electrode 12 to the positive electrode 11 .

From the above point of view, it is particularly preferable that the conductive material constituting the conductor 1 is at least one selected from the group consisting of graphite sheet, carbon paper, carbon cloth, carbon felt and stainless steel (SUS).

As shown in FIGS. 1 to 3, the length L1 in the vertical direction Y in the water treatment structure 10 is preferably longer than the length L2 in the width direction Z perpendicular to the vertical direction Y. As shown in FIGS. Moreover, it is particularly preferable that the water treatment structure 10 has a plate shape. As a result, the distance between the negative electrode 12 in the water treatment structure 10 and the water surface 30a of the water to be treated 30 increases, and the surroundings of the negative electrode 12 become anaerobic. Therefore, anaerobic microorganisms adhere to the negative electrode 12 of the water treatment structure 10, and organic substances can be efficiently oxidized. In addition, in the water treatment structure 10 , a potential difference is generated between the site (positive electrode 11 ) where the oxygen reduction reaction occurs and the site (negative electrode 12 ) where the organic matter oxidation reaction occurs. It can conduct electrons efficiently.

The length L1 in the vertical direction Y in the water treatment structure 10 is preferably twice or more the length L2 in the width direction Z, more preferably 5 times or more, and 8 times or more. is more preferable, and 10 times or more is particularly preferable. Although the upper limit of the length L1 in the vertical direction Y in the water treatment structure 10 is not particularly limited, it is preferably 50 times or less the length L2 in the width direction Z, for example.

As described above, the shape of the water treatment structure 10 is more preferably plate-like. However, the shape of the water treatment structure 10 is not limited to such an aspect, and may be rod-like or cord-like as long as the length L1 in the vertical direction Y can be made longer than the length L2 in the width direction Z. may Since the shape of the water treatment structure is plate-like, rod-like, or string-like, the distance between the negative electrode 12 in the water treatment structure 10 and the water surface 30a of the water to be treated 30 is increased. of anaerobic microorganisms can adhere. Moreover, in the water treatment structure 10, it is possible to control the metabolism of microorganisms by generating a potential difference between the positive electrode 11 in which an oxygen reduction reaction occurs and the negative electrode 12 in which an organic matter oxidation reaction occurs. When the shape of the water treatment structure 10 is rod-like or string-like, the length L2 in the width direction Z perpendicular to the vertical direction Y refers to the maximum linear distance between two points on the outer circumference of the water treatment structure 10. .

As shown in FIG. 4 , it is preferable that the oxygen reduction catalyst 2 is supported on the site (positive electrode 11 ) where the oxygen reduction reaction occurs in the water treatment structure 10 . By supporting the oxygen reduction catalyst 2 , the oxygen reduction reaction by oxygen, hydrogen ions and electrons can be efficiently advanced in the positive electrode 11 . The oxygen reduction catalyst 2 may be supported on the surface of the conductor 1 or may be supported inside the conductor 1 .

The oxygen reduction catalyst 2 that can be supported on the conductor 1 is not particularly limited, but may contain platinum. The oxygen reduction catalyst 2 may also contain carbon particles doped with at least one kind of nonmetallic atoms and metal atoms. Atoms with which the carbon particles are doped are not particularly limited. The nonmetallic atom is preferably at least one selected from the group consisting of, for example, nitrogen, boron, sulfur and phosphorus atoms. Also, the metal atom is preferably at least one of, for example, an iron atom and a copper atom.

The oxygen reduction catalyst 2 may be bound to the conductor 1 using a binder. That is, the oxygen reduction catalyst 2 may be supported on the surface and inside the pores of the conductor 1 using a binder. As a result, it is possible to prevent the oxygen reduction catalyst 2 from being detached from the conductor 1 and the deterioration of the oxygen reduction characteristics. As the binder, for example, at least one selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride (PVDF), and ethylene-propylene-diene copolymer (EPDM) can be used. NAFION (registered trademark) can also be used as the binder.

Anaerobic microorganisms that decompose organic matter in the water 30 to be treated to generate hydrogen ions and electrons adhere to the site (negative electrode 12 ) in the water treatment structure 10 where an organic matter oxidation reaction occurs. The anaerobic microorganisms 3 do not require oxygen for growth, and further do not require air for oxidatively decomposing organic matter in the water 30 to be treated. Therefore, it is possible to greatly reduce the electric power required for sending air. In addition, since the free energy acquired by microorganisms is small, it is possible to reduce the amount of sludge generated.

The anaerobic microorganisms adhering to the negative electrode 12 of the water treatment structure 10 are preferably electroproducing bacteria having an extracellular electron transfer mechanism, for example. Specific examples of anaerobic microorganisms include Geobacter, Shewanella, Aeromonas, Geothrix, and Saccharomyces.

Anaerobic microorganisms may adhere to the negative electrode 12 by stacking and fixing a biofilm containing anaerobic microorganisms on the negative electrode 12 of the water treatment structure 10 . A biofilm generally refers to a three-dimensional structure containing a microbial population and an extracellular polymeric substance (EPS) produced by the microbial population. However, the anaerobic microorganisms may adhere to the negative electrode 12 without depending on the biofilm. In addition, the anaerobic microorganisms may adhere not only to the surface of the negative electrode 12 but also to the inside.

Here, anaerobic microorganisms include facultative anaerobes and obligate anaerobes. Facultative anaerobes are anaerobes that can live without the presence of oxygen. Obligatory anaerobes are anaerobes that cannot live in the presence of oxygen and die out. Both facultative anaerobes and obligate anaerobes adhere to the negative electrode 12 .

Aerobic microorganisms that generate water by reacting oxygen in the gas phase 40 with hydrogen ions and electrons may be attached to the site (positive electrode 11) where the oxygen reduction reaction occurs in the water treatment structure 10. Examples of such aerobic microorganisms 4 include Sphingobacterium, Acinetobacterium, and Acinetobacter.

It should be noted that the water treatment structure 10 may be composed only of the conductor 1 without supporting the oxygen reduction catalyst 2 on the positive electrode 11 . As will be described later, when both the anaerobic microorganisms 3 and the aerobic microorganisms 4 are present in the water 30 to be treated, the anaerobic microorganisms 3 adhere to the positive electrode 11 and the aerobic microorganisms 4 adhere to the negative electrode 12. By doing so, a local cell reaction occurs, and it becomes possible to oxidatively decompose the organic matter.

(Treatment tank)
The water treatment apparatus 100 includes a substantially rectangular parallelepiped treatment tank 20 that holds therein water to be treated 30 containing organic matter. A front wall 23 of the treatment tank 20 is provided with an inlet 21 for supplying the water 30 to be treated to the treatment tank 20 . An outflow port 22 is provided in the rear wall 24 of the treatment tank 20 for discharging the treated water 30 from the treatment tank 20 .

The water to be treated 30 is continuously supplied to the inside of the treatment tank 20 through the inflow port 21 . Moreover, as shown in FIGS. 1 and 2, the water treatment structure 10 is arranged inside the treatment tank 20 so that the negative electrode 12 and the positive electrode 11 are partly immersed in the water 30 to be treated. Therefore, the water to be treated 30 supplied from the inlet 21 of the treatment tank 20 flows while being in contact with the water treatment structure 10 and then discharged from the outlet 22 .

(Aerator)
The water treatment device 100 further includes an aeration device 50 that intermittently aerates the water 30 to be treated with gas containing oxygen. The aeration device 50 includes an air diffusion member 51 having a hole for diffusing gas, an aeration blower 52 for pressure-feeding the gas, and an aeration blower 52 for feeding the gas to the air diffusion member 51. and a pipe 53 of . The aeration device 50 further includes a controller 54 electrically connected to the aeration blower 52 and controlling the operation of the aeration blower 52 .

The diffuser member 51 is a member having a large number of holes through which gas can flow. The diffuser member 51 is not particularly limited, but for example, a porous ceramic diffuser plate in which coarse ceramic particles are bonded with a binder or the like, or a synthetic resin diffuser plate can be used. A membrane diffuser can also be used as the diffuser member 51 .

A pipe 53 for supplying gas from the outside of the processing tank 20 is connected to the air diffusion member 51 . Specifically, one end of a hollow pipe 53 is connected to the lower portion of the diffuser member 51 . The pipe 53 penetrates the rear wall 24 of the processing bath 20 and extends outside the processing bath 20 . The other end of the pipe 53 is connected to an aeration blower 52 for pumping gas.

The control unit 54 is electrically connected to the aeration blower 52, and is composed of a microcomputer including a CPU, RAM, ROM, hard disk, etc., and an electronic circuit. The control unit 54 controls the operation and stoppage of the aeration blower 52 , the time of the operation and stoppage, and the air volume of the gas supplied to the air diffusion member 51 .

The gas to be aerated from the aeration device 50 to the water to be treated 30 is an oxygen-containing gas, such as air.

Next, operation|movement of the water treatment apparatus 100 of this embodiment is demonstrated. In the water treatment apparatus 100, the water treatment structure 10 is installed inside the treatment tank 20 holding the water 30 to be treated. At this time, as shown in FIG. 2, the water treatment structure 10 is installed inside the treatment tank 20 so that the main surface 1a of the conductor 1 is substantially parallel to the vertical direction Y. As shown in FIG.

When the water treatment structure 10 is installed inside the treatment tank 20, as shown in FIGS. ing. Furthermore, the positive electrode 11 of the water treatment structure 10 is also in contact with the water 30 to be treated. Since the water 30 to be treated that contacts the positive electrode 11 is located near the gas phase 40, the dissolved oxygen concentration is high.

The negative electrode 12 of the water treatment structure 10 is immersed inside the water 30 to be treated. Since the length L1 in the vertical direction Y in the water treatment structure 10 is longer than the length L2 in the width direction Z, the negative electrode 12 is away from the water surface 30a, and the dissolved oxygen concentration is low. .

As described above, since the water to be treated 30 in contact with the positive electrode 11 of the water treatment structure 10 has a high dissolved oxygen concentration, when the water to be treated 30 contains the aerobic microorganisms 4, Aerobic microorganisms 4 adhere to the positive electrode 11 . Here, for example, when the conductor 1 is a porous body, the water 30 to be treated rises due to capillary action, and the water 30 to be treated can be held up to the upper end of the conductor 1 . Therefore, the aerobic microorganisms 4 can adhere to the entire upper portion of the water treatment structure 10 .

Further, since the negative electrode 12 of the water treatment structure 10 is away from the water surface 30a and the surrounding oxygen concentration is low, the anaerobic microorganisms 3 adhere to the negative electrode 12 .

In the water treatment apparatus 100 having such a configuration, at the negative electrode 12 of the water treatment structure 10, the oxidation reaction of organic matter contained in the water to be treated 30 progresses due to the metabolism of the anaerobic microorganisms 3, and hydrogen ions (H ⁺ ) and Electrons (e ⁻ ) are produced. Hydrogen ions generated by the oxidation reaction move to the positive electrode 11 through the internal space of the conductor 1 . Furthermore, electrons generated by the oxidation reaction move to the positive electrode 11 through the conductor 1 .

Then, in the positive electrode 11, the electrons and hydrogen ions transferred from the negative electrode 12 react with oxygen molecules through the action of the oxygen reduction catalyst and/or the aerobic microorganisms, thereby producing water. In this manner, the oxidation reaction of organic matter proceeds at the negative electrode 12 and the reduction reaction of oxygen proceeds at the positive electrode 11, so that the water treatment structure as a whole forms a local battery circuit. As described above, the catalytic action of the anaerobic microorganisms 3 in the negative electrode 12 decomposes the organic substances in the water 30 to be treated, and the water 30 to be treated can be purified.

Here, in the water treatment structure 10, a potential difference is generated between the positive electrode 11 where the oxygen reduction reaction occurs and the negative electrode 12 where the organic matter oxidation reaction occurs. As a result, electrons are conducted from the negative electrode 12 to the positive electrode 11 through the conductor 1 . Specifically, since the length L1 in the vertical direction Y in the water treatment structure 10 is longer than the length L2 in the width direction Z, the positive electrode 11 and the negative electrode 12 are spaced apart. Since the conductor 1 present between the positive electrode 11 and the negative electrode 12 has high electrical resistivity, a potential difference is generated between the positive electrode 11 and the negative electrode 12 . That is, the electrical resistivity of the conductor 1 between the positive electrode 11 and the negative electrode 12 is relatively high, so that the positive electrode 11 and the negative electrode 12 can be controlled to have appropriate potentials. It becomes possible to secure a potential difference. Since the metabolism of microorganisms is controlled by ensuring the potential difference, electrons are efficiently conducted from the negative electrode 12 to the positive electrode 11 through the conductor 1, and the decomposition efficiency of organic matter in the water 30 to be treated is improved. can be increased. Furthermore, in the water treatment structure 10, there is no need to provide wiring such as an external circuit and a boosting system for securing a potential difference, and the positive electrode 11 and the negative electrode 12 are short-circuited, so that the structure can be simplified. .

Here, in the water to be treated 30, both facultative anaerobes (geobacter) and obligate anaerobes, which are power generating bacteria, live as anaerobic microorganisms. Therefore, both facultative anaerobes and obligate anaerobes adhere to the negative electrode 12 as anaerobic microorganisms. Facultative anaerobes have a higher ability to decompose organic substances in the water 30 to be treated and generate hydrogen ions and electrons than obligate anaerobes. Therefore, it is preferable that the anaerobic microorganisms living in the water 30 to be treated and the anaerobic microorganisms adhering to the negative electrode 12 are more facultative anaerobes than obligate anaerobes.

Therefore, in the present embodiment, the water to be treated 30 is intermittently aerated with an oxygen-containing gas using the aerator 50 . That is, the aeration device 50 is used to alternately repeat the aeration state and stop state of the water to be treated 30, and in the aeration state, the oxygen-containing gas is brought into contact with the facultative anaerobes and the obligate anaerobes. ing. As a result, the facultative anaerobes remain inhabiting the water 30 to be treated, but most of the obligate anaerobes die. Moreover, although the facultative anaerobes adhering to the negative electrode 12 remain, some of the obligate anaerobes die, and the amount of the obligate anaerobes decreases. Therefore, in the water to be treated 30 and the negative electrode 12, facultative anaerobes can be made dominant. As a result, the organic substances in the water 30 to be treated are easily decomposed by the facultative anaerobic bacteria, so that the water to be treated 30 can be purified efficiently.

Here, if the water 30 to be treated is continuously aerated, the amount of dissolved oxygen in the water 30 to be treated increases, making it difficult to maintain the anaerobic atmosphere around the negative electrode 12 . Therefore, the water to be treated 30 is intermittently aerated. Specifically, it is preferable that the aeration device 50 alternately repeats the aeration operation state and the aeration stop state at regular intervals. The time during which aeration is performed and the time during which the aeration is stopped are adjusted according to the flow rate of the water to be treated 30, the amount and ratio of facultative anaerobes and obligate anaerobes living in the water to be treated 30, and the like. be able to. However, the duration of the aeration state can be 10 to 20 minutes, and the duration of the non-aeration state can be 40 minutes to 3 hours. For example, it is preferred that the aeration is performed for 20 minutes and the aeration is stopped for 40 minutes, alternating between 20 minutes of aeration and 40 minutes of suspension.

In addition, the aeration air volume in the aeration state is not particularly limited as long as it is an amount that allows facultative anaerobes to dominate, but for example, it is preferable not to exceed the aeration air volume in general aerobic treatment. .

The intermittent aeration of the water to be treated 30 may be performed from the beginning of purification of the water to be treated 30 by the water treatment structure 10, or from the stage when the efficiency of purification of the water to be treated 30 by the water treatment structure 10 is lowered. may be implemented. Further, the intermittent aeration of the water 30 to be treated may be performed continuously while the water treatment structure 10 is purifying the water 30 to be treated. You can stop when you have improved.

Thus, the water treatment apparatus 100 of the present embodiment contacts the water to be treated 30 inhabited by the anaerobic microorganisms 3 having facultative anaerobes and obligate anaerobes, and the anaerobic microorganisms 3 adhere to the water. and a positive electrode 11 electrically connected to the negative electrode 12 and in contact with the gas phase 40 containing oxygen and the water 30 to be treated. The water treatment device 100 further includes an aeration device 50 that intermittently aerates the water 30 to be treated with gas containing oxygen. The aeration device 50 alternately repeats the active state and the stopped state of aeration, and in the active state of aeration, the gas containing oxygen is brought into contact with the anaerobic microorganisms 3 .

In the water treatment method of the present embodiment, the negative electrode 12 is in contact with the water to be treated 30 in which anaerobic microorganisms 3 having facultative anaerobes and obligate anaerobes live, and to which the anaerobic microorganisms 3 adhere; This is a water treatment method using a water treatment structure 10 electrically connected to a negative electrode 12 and having a gas phase 40 containing oxygen and a positive electrode 11 in contact with water to be treated 30 . In the water treatment method, by aerating a gas containing oxygen to the water 30 to be treated, an aeration execution state in which the gas comes into contact with the anaerobic microorganisms 3, and an aeration stop state in which the aeration of the gas is stopped. Repeat alternately.

In the water treatment apparatus 100 and the water treatment method of the present embodiment, the aeration state and stop state of the water to be treated 30 are alternately repeated. contact with sexually transmitted organisms. As a result, among the anaerobic microorganisms 3 living in the water 30 to be treated in the treatment tank 20, the obligate anaerobes are removed and the facultative anaerobes remain. Furthermore, although the facultative anaerobes adhering to the negative electrode 12 remain, some of the obligate anaerobes are killed and the amount of the obligate anaerobes is reduced. Therefore, since facultative anaerobes are dominant on the surface of the water 30 to be treated and the surface of the negative electrode 12, the organic matter in the water 30 to be treated is easily decomposed by the facultative anaerobes. Purification can be performed efficiently.

In addition, in this embodiment, the whole water 30 to be treated may be aerated with an oxygen-containing gas. Alternatively, as shown in FIGS. 2 and 3, an aeration member 51 may be provided under the negative electrode 12 to aerate the surroundings of the negative electrode 12 . Also, the diffuser member 51 may be arranged upstream of the negative electrode 12 , for example, in the vicinity of the front wall 23 of the processing tank 20 .

In the water treatment apparatus 100 shown in FIGS. 1 to 3, one water treatment structure 10 is installed inside one treatment tank 20 . However, the present embodiment is not limited to such an aspect, and a plurality of water treatment structures 10 may be installed inside the treatment tank 20 . By installing a plurality of water treatment structures 10 inside one treatment tank 20, it is possible to purify organic substances in the water 30 to be treated more efficiently.

The negative electrode 12 of the water treatment structure 10 may be modified with an electron transfer mediator molecule. Alternatively, the water to be treated 30 in the treatment tank 20 may contain electron transfer mediator molecules. As a result, electron transfer from the anaerobic microorganisms 3 to the negative electrode 12 is promoted, and more efficient liquid treatment can be achieved.

It should be noted that the water treatment apparatus of the present embodiment is provided with the water treatment structure 10 and the aeration apparatus 50, thereby efficiently removing organic substances in the waste water by an anaerobic treatment method, and obtaining good water quality. . Therefore, in the water treatment apparatus, the treatment tank 20 is not an essential component for obtaining the above effects.

[Second embodiment]
Next, a water treatment device according to a second embodiment will be described. In the water treatment apparatus 100 of the first embodiment, the water treatment structure 10 has a structure in which the positive electrode 11 and the negative electrode 12 are integrated. That is, the water treatment structure 10 is composed of a plate member having a positive electrode 11 and a negative electrode 12 . However, the water treatment structure is not limited to such a structure, and may be of a so-called cassette type.

A water treatment apparatus 200 according to this embodiment includes a water treatment structure 110 having a positive electrode 111 and a negative electrode 112, as shown in FIGS. The water treatment apparatus 200 further includes a treatment tank 120 arranged such that the water treatment structure 110 is immersed in the water 130 to be treated.

(water treatment structure)
The water treatment structure 110 includes a positive electrode 111 and a negative electrode 112 electrically connected to the positive electrode 111 and attached with anaerobic microorganisms. In the water treatment structure 110 , the positive electrode 111 and the negative electrode 112 are arranged so as to face each other, and a gap exists between the positive electrode 111 and the negative electrode 112 .

As shown in FIG. 7, the positive electrode 111 is laminated and fixed to the spacer member 115 . The spacer member 115 is a U-shaped frame member along the outer periphery of the surface 111a of the positive electrode 111, and has an open top. Side surface 115 a of spacer member 115 is joined to the outer peripheral portion of surface 111 a of positive electrode 111 , and the opposite side surface of side surface 115 a is joined to the outer peripheral portion of surface 116 a of plate member 116 .

As shown in FIGS. 6 and 8, the laminate formed by laminating the positive electrode 111, the spacer member 115, and the plate member 116 is placed inside the processing bath 120 so as to form a gas phase 140 communicating with the atmosphere. placed. Water to be treated 130 is held inside the treatment tank 120 , and the gas diffusion layer 114 of the positive electrode 111 and the negative electrode 112 are immersed in the water to be treated 130 .

The positive electrode 111 is provided with a water-repellent layer 113 having water repellency, and the plate member 116 is made of a flat plate material that does not allow the water 130 to be treated to pass therethrough. Therefore, the water to be treated 130 held inside the treatment tank 120 is separated from the internal space formed by the positive electrode 111 , the spacer member 115 and the plate member 116 , and the internal space is in the gas phase 140 . The water treatment apparatus 200 is configured such that the gas phase 140 is exposed to the outside air, or air is supplied to the gas phase 140 from the outside by, for example, a pump.

The positive electrode 111 is composed of a gas diffusion electrode including a water-repellent layer 113 and a gas diffusion layer 114 superimposed so as to be in contact with the water-repellent layer 113 . Oxygen in the gas phase 140 can be easily supplied to the catalyst in the positive electrode 111 by using such a thin-plate gas diffusion electrode.

The water repellent layer 113 is a layer having both water repellency and oxygen permeability. The water-repellent layer 113 allows the movement of oxygen from the gas phase 140 toward the water 130 to be treated while satisfactorily separating the gas phase 140 and the water 130 to be treated in the water treatment structure 110 . The water-repellent layer 113 is in contact with the gas phase 140 containing oxygen, and supplies oxygen to the gas diffusion layer 114 substantially uniformly.

It is preferable that the water-repellent layer 113 be a porous material so that the oxygen can diffuse. Also, the material forming the water-repellent layer 113 is not particularly limited as long as it has water repellency and can diffuse oxygen in the gas phase 140 . Materials constituting the water-repellent layer 113 include, for example, polyethylene, polypropylene, polybutadiene, nylon, polytetrafluoroethylene (PTFE), ethyl cellulose, poly-4-methylpentene-1, butyl rubber, and polydimethylsiloxane (PDMS). At least one selected from the group can be used.

Gas diffusion layer 114 comprises a porous conductive material and an oxygen reduction catalyst carried on the conductive material. By providing the positive electrode 111 with such a gas diffusion layer 114 , it becomes possible to conduct electrons generated by a local cell reaction, which will be described later, between the catalyst and the external circuit 160 .

The conductive material in the gas diffusion layer 114 can be composed of, for example, one or more materials selected from the group consisting of carbonaceous substances, conductive polymers, semiconductors and metals. Also, the same oxygen reduction catalyst as in the first embodiment can be used in the gas diffusion layer 114 .

As in the first embodiment, the negative electrode 112 according to the present embodiment supports anaerobic microorganisms and produces hydrogen ions and electrons from organic matter in the water 130 to be treated by the catalytic action of the anaerobic microorganisms.

The negative electrode 112 has a structure in which anaerobic microorganisms are supported on a conductive sheet. The conductive sheet may be a metal plate having a plurality of through holes in the thickness direction. Alternatively, a graphite sheet may be used as the conductive sheet of the negative electrode 112 .

The water treatment structure 110 may further include an ion transfer layer (not shown) provided between the positive electrode 111 and the negative electrode 112 and having proton permeability. The ion migration layer has electrical insulation properties and also has a function of allowing hydrogen ions generated at the negative electrode 112 to pass through and move to the positive electrode 111 side. As the ion migration layer, for example, an ion exchange membrane using an ion exchange resin can be used. Also, as the ion transfer layer, a porous membrane having pores through which hydrogen ions can pass may be used.

(external circuit)
As shown in FIGS. 6 and 8 , the positive electrode 111 and the negative electrode 112 are electrically connected via an external circuit 160 . As will be described later, the catalytic action of the anaerobic microorganisms supported on the negative electrode 112 decomposes organic matter in the water 130 to be treated to generate electrons. Electrons generated at the negative electrode 112 move to the external circuit 160 and from the external circuit 160 to the positive electrode 111 . At this time, the electrical energy flowing in the closed circuit can be recovered by the external circuit 160 .

(Treatment tank and aeration equipment)
The water treatment apparatus 200 includes a treatment tank 120 having an inlet 121 provided in the front wall 123 and an outlet 122 provided in the rear wall 124, as in the first embodiment.

Further, the water treatment apparatus 200 includes an air diffusion member 151 for diffusing gas, an aeration blower 152 for pumping the gas, and the air from the aeration blower 52 to the air diffusion member 151, as in the first embodiment. It comprises an aeration system 150 with a supply line 153 . The aeration device 150 further includes a controller 154 electrically connected to the aeration blower 152 and controlling the operation of the aeration blower 152 . In addition, in FIG. 8 , the air diffusion member 51 is arranged below the negative electrode 112 , but the air diffusion member 51 may be arranged upstream of the negative electrode 112 .

Next, the operation of the water treatment device 200 of this embodiment will be described. As shown in FIGS. 6 and 8, when the water treatment structure 110 including the positive electrode 111 and the negative electrode 112 is immersed in the water 130 to be treated, the gas diffusion layer 114 and the negative electrode 112 of the positive electrode 111 are immersed in the water 130 to be treated. , part of the water-repellent layer 113 is exposed to the gas phase 140 .

During operation of the water treatment apparatus 200 , the negative electrode 112 is supplied with the water to be treated 130 containing organic matter, and the positive electrode 111 is supplied with air. At this time, air is continuously supplied through an opening provided in the upper portion of the spacer member 115 .

Then, in the positive electrode 111 , oxygen permeates the water-repellent layer 113 and diffuses into the gas diffusion layer 114 . At the negative electrode 112, hydrogen ions and electrons are generated from organic matter in the water 130 to be treated by the catalytic action of the anaerobic microorganisms. The hydrogen ions generated at the negative electrode 112 move toward the positive electrode 111 and reach the gas diffusion layer 114 in the positive electrode 111 . The generated electrons move to the external circuit 160 through the conductive sheet of the negative electrode 112 and then move from the external circuit 160 to the gas diffusion layer 114 of the positive electrode 111 . Then, the hydrogen ions and electrons combine with oxygen due to the action of the oxygen reduction catalyst in the gas diffusion layer 114 and are consumed as water. At this time, the electric energy flowing in the closed circuit is recovered by the external circuit 160 . Thus, the water treatment structure 110 can decompose organic matter in the water 130 to be treated by the action of anaerobic microorganisms in the negative electrode 112 .

Here, in the water treatment apparatus 200 of this embodiment, both facultative anaerobes and obligate anaerobes live in the water to be treated 130 as anaerobic microorganisms, as in the first embodiment. Both facultative anaerobes and obligate anaerobes are attached to the negative electrode 112 as anaerobic microorganisms. Therefore, the aeration device 150 is used to alternately repeat the aeration state and stop state of the water to be treated 130, and in the aeration state, the oxygen-containing gas comes into contact with the facultative anaerobes and the obligate anaerobes. I am letting As a result, although the facultative anaerobes remain inhabiting the water 130 to be treated, most of the obligate anaerobes are killed, so that the facultative anaerobes can be made dominant. Furthermore, although the facultative anaerobes remain attached to the negative electrode 112, some of the obligate anaerobes die and the amount of the obligate anaerobes decreases. As a result, the organic matter in the water 130 to be treated is easily decomposed by the facultative anaerobic bacteria, so the water to be treated 130 can be purified efficiently.

Also in the present embodiment, it is preferable that the aeration device 150 alternately repeats the aeration operation state and the aeration stop state at regular intervals. Also, the duration of the aeration state can be 10 to 20 minutes, and the duration of the aeration stopped state can be 40 minutes to 3 hours.

EXAMPLES Hereinafter, the present embodiment will be described in more detail with reference to examples and comparative examples, but the present embodiment is not limited to these examples.

[Production of water treatment structure]
First, a water treatment structure used in Example 1 and Comparative Example 1 and a water treatment structure used in Example 2 were produced.

(Example 1 and Comparative Example 1)
First, two plate-shaped graphite sheets (conductors) having a length of 68 cm, a width of 30 cm, and a thickness of 0.5 cm were prepared. Then, a plurality of through-holes were formed in a portion of the graphite sheet other than the upper 8 cm. In addition, the said through-hole is pierced along the thickness direction of a graphite sheet.

Next, a catalyst slurry was prepared by dispersing an iron-based catalyst composed of carbon black supporting iron and nitrogen in a mixed solution of a Nafion solution and ethanol. Then, the obtained catalyst slurry was applied to the upper 8 cm portion of the graphite sheet and dried. As a result, two water treatment structures carrying an iron-based catalyst on the upper part of the graphite sheet were obtained. In addition, FIG. 9 shows an example of a water treatment structure in which an iron-based catalyst is supported on the upper part of a graphite sheet having through holes, and the upper black part is the part where the iron-based catalyst is supported.

(Example 2)
The graphite sheets with through holes formed in Example 1 and Comparative Example 1 were used as they were as water treatment structures. That is, unlike the water treatment structures of Example 1 and Comparative Example 1, the water treatment structure of Example 2 did not carry an iron-based catalyst.

[evaluation]
(Example 1)
A treatment tank having an inlet and an outlet and having a capacity of about 20 L was prepared. Furthermore, an aerator for aerating the water to be treated with air was installed in the treatment tank. And the water treatment apparatus 100 was obtained by arrange|positioning the water-treatment structure produced as mentioned above in the inside of the said treatment tank.

Next, as shown in FIG. 10, on the upstream side of the water treatment device 100, a high-speed filtration device 210 for filtering the water to be treated and a high-speed filtration water tank 220 for storing the high-speed filtered water to be treated were installed. . Further, on the downstream side of the water treatment device 100, a sludge storage tank 240 for removing sludge in the treated water purified by the water treatment device 100 is installed. A diaphragm pump 230 was installed between the high-speed filtration water tank 220 and the water treatment apparatus 100 to supply the high-speed filtered water to be treated from the high-speed filtration treatment water tank 220 to the inlet of the water treatment apparatus 100 . Sewage (actual sewage) was used as the water to be treated. Thus, the experimental device of Example 1 was produced.

Next, the water to be treated was sent to the high-speed filtration device 210 to remove solids in the sewage, and the water to be treated that had undergone high-speed filtration was stored in the high-speed filtration water tank 220 . Then, the high-speed filtered water to be treated was fed from the high-speed filtration water tank 220 to the water treatment apparatus 100 using a diaphragm pump. The amount of water to be treated supplied to the water treatment apparatus 100 was adjusted so that the hydraulic retention time (HRT) in the treatment tank was 4 hours. After that, the treated water treated by the water treatment device 100 was discharged into the sludge storage tank.

Such purification treatment of the water to be treated (sewage) was carried out for about four months. Moreover, during this period, in the water treatment apparatus 100, the water to be treated was continuously aerated intermittently, and the water was intermittently brought into contact with the air. In the intermittent aeration, 10 minutes of aeration and 50 minutes of aeration stop were alternately repeated.

Then, in the last 54 days of the purification treatment, the water to be treated that has undergone high-speed filtration and the treated water discharged from the water treatment apparatus 100 are sampled about once a week, and Biological oxygen demand (SC-BOD) for soluble carbonaceous organics was measured respectively.

Furthermore, the SC-BOD removal rate is calculated according to Equation 1 from the average SC-BOD concentration of the high-speed filtered water to be treated and the average SC-BOD concentration of the treated water discharged from the water treatment equipment. did. It should be noted that the larger the SC-BOD removal rate, the higher the ability of the water treatment apparatus to purify organic matter.
[Number 1]
[SC-BOD removal rate] = (AB) / A
A: Average value of SC-BOD concentration of water to be treated that has undergone high-speed filtration B: Average value of SC-BOD concentration of treated water discharged from water treatment equipment

(Example 2)
In the same manner as in Example 1 except that the water treatment structure of Example 2 was used, the SC-BOD concentration of the water to be treated that was high-speed filtered and the SC-BOD concentration of the treated water discharged from the water treatment apparatus was measured and the SC-BOD removal rate was calculated.

(Comparative example 1)
In the water treatment apparatus 100 of Example 1, in the same manner as in Example 1 except that intermittent aeration was not performed at all, the SC-BOD concentration of the water to be treated that was high-speed filtered and the treatment discharged from the water treatment apparatus The SC-BOD concentration of water was measured and the SC-BOD removal rate was calculated.

(Comparative example 2)
Purification treatment was performed in the same manner as in Example 1, except that the water treatment structure of Example 1 was replaced with tricarnet. The trical net is a non-knit square-mesh type resin net that is neither electrically conductive nor has a water purification function. In other words, Comparative Example 2 is an example in which only intermittent aeration was performed on water to be treated that had been subjected to high-speed filtration. Then, in the same manner as in Example 1, the SC-BOD concentration of the high-speed filtered water to be treated and the SC-BOD concentration of the treated water discharged from the water treatment apparatus were measured, and the SC-BOD removal rate was calculated. .

Table 1 shows the average SC-BOD concentration of the high-speed filtered water to be treated, the average SC-BOD concentration of the treated water discharged from the water treatment apparatus 100, and their standard deviations in each example. Table 1 also shows the SC-BOD removal rate of each example.

From Table 1, Examples 1 and 2 using the water treatment structure and performing intermittent aeration have an SC-BOD removal rate of 74% or more for raw water (water to be treated that has been subjected to high-speed filtration). became. Moreover, in Examples 1 and 2, the SC-BOD concentration was less than 15 mg/L, and good purification performance could be exhibited. On the other hand, in Comparative Example 1 in which a water treatment structure was used but intermittent aeration was not performed, the SC-BOD removal rate was 70%. Therefore, it can be seen that the purification efficiency of the water to be treated is improved by performing intermittent aeration. Further, in Comparative Example 2 in which only intermittent aeration was performed, the SC-BOD removal rate was 63%. From this, it can be seen that the purification efficiency is greatly improved by combining the water treatment structure and the intermittent aeration.

From Examples 1 and 2, it can be seen that although the SC-BOD removal rate is improved by supporting the oxygen reduction catalyst on the positive electrode, the SC-BOD removal rate increases even if the oxygen reduction catalyst is not supported. This is probably because aerobic microorganisms adhere to the positive electrode and react oxygen in the gas phase with hydrogen ions and electrons to produce water. Therefore, regardless of the presence or absence of the oxygen reduction catalyst, it can be seen that the purification efficiency is enhanced by combining the water treatment structure and the intermittent aeration. Moreover, since purification efficiency is increased without using a catalyst, the cost of the water treatment structure can be reduced. Additionally, the catalyst in the water treatment structure may degrade, requiring replacement of the water treatment structure. However, if no catalyst is used, there is no need to replace the water treatment structure, further reducing costs.

FIG. 11 shows the result of observation of the surface of the water treatment structure of each example after purification treatment of the water to be treated. 11(a) is a photograph showing the surface of the water treatment structure of Example 1, FIG. 11(b) is a photograph showing the surface of the water treatment structure of Example 2, and FIG. 4 is a photograph showing the surface of the water treatment structure of Comparative Example 1. FIG. From FIG. 11, it can be seen that a large amount of microorganisms adhere to the entire negative electrode of each water treatment structure. Moreover, from FIG. 11(a), in Example 1, the attached microorganisms were brown. From FIG. 11(b), in Example 2, the adhering microorganisms were gray. On the other hand, from FIG. 11(c), in Comparative Example 1 in which intermittent aeration was not performed, the adhering microorganisms were dark green. As described above, in the water treatment structure of each example, since the color of the attached microorganisms is different, it can be understood that the microorganism species are different.

Here, in the water treatment structure of each example, the negative electrode is immersed in the water to be treated, and from Table 1, the microorganisms contribute to the purification of the water to be treated. It is considered to be anaerobic microorganisms, which are power-generating bacteria, and their symbiotic microorganisms. Since intermittent aeration was performed in Examples 1 and 2, the anaerobic microorganisms adhering to the negative electrode are considered to be facultative anaerobes rather than obligatory anaerobes. On the other hand, since intermittent aeration was not performed in Comparative Example 1, the anaerobic microorganisms adhering to the negative electrode are considered to be both obligatory and facultative anaerobes.

In this way, by intermittently aerating the water to be treated with a gas containing oxygen, facultative anaerobes are dominant in the water to be treated and the negative electrode, and purification of the water to be treated is efficiently performed. can be done.

Although the present embodiment has been described above, the present embodiment is not limited to these, and various modifications are possible within the scope of the gist of the present embodiment.

2 Oxygen reduction catalyst 3 Anaerobic microorganism 4 Aerobic microorganism 10,110 Water treatment structure 11,111 Positive electrode 12,112 Negative electrode 20,120 Treatment tank 30,130 Water to be treated 40,140 Gas phase 50,150 Aerator 100, 200 water treatment equipment

Claims (8)

A negative electrode in contact with water to be treated in which anaerobic microorganisms having facultative anaerobes and obligate anaerobes live, and to which the anaerobic microorganisms adhere, is electrically connected to the negative electrode, and oxygen is supplied. a water treatment structure comprising: a gas phase containing
an aeration device for intermittently aerating gas containing oxygen to the water to be treated;
with
The water treatment apparatus, wherein the aeration device alternates between an active state and a stopped state of aeration, and in the active state of aeration, the gas is brought into contact with the anaerobic microorganisms. 2. The water treatment apparatus according to claim 1, further comprising a treatment tank that holds therein said water treatment structure, said water to be treated, and at least part of said aerator. 3. The method according to claim 1, wherein said facultative anaerobes remain in said water to be treated and said obligate anaerobes are removed from said water to be treated by bringing said gas into contact with said anaerobic microorganisms. water treatment equipment. 4. The water treatment apparatus according to any one of claims 1 to 3, wherein said aeration device alternately repeats an operation state and a stop state of said aeration at regular intervals. A water treatment apparatus according to any one of claims 1 to 4, wherein the duration of the active state of aeration is 10-20 minutes and the duration of the non-aeration state is 40 minutes to 3 hours. The water treatment device according to any one of claims 1 to 5, wherein the positive electrode has aerobic microorganisms adhered thereto, or carries an oxygen reduction catalyst. In the water treatment structure, the negative electrode and the positive electrode are integrated,
The water treatment apparatus according to any one of claims 1 to 6, wherein the water treatment structure has a plate-like, bar-like or string-like shape. A negative electrode in contact with water to be treated in which anaerobic microorganisms having facultative anaerobes and obligate anaerobes live, and to which the anaerobic microorganisms adhere, is electrically connected to the negative electrode, and oxygen is supplied. A water treatment method using a water treatment structure comprising a gas phase containing and a positive electrode that contacts the water to be treated,
By aerating a gas containing oxygen to the water to be treated, an aeration execution state in which the gas is brought into contact with the anaerobic microorganisms and an aeration stop state in which the aeration of the gas is stopped are alternately repeated. Processing method.

Images