JP2018006197A - Microorganism adhesion prevention device, microorganism adhesion prevention method, wastewater treatment device, and wastewater treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microorganism adhesion prevention device, a microorganism adhesion prevention method, a wastewater treatment device, and a wastewater treatment method, which are capable of preventing microorganisms having an extracellular electron transfer capability from adhering to a cathode.SOLUTION: A microorganism adhesion prevention device 100 according to the present invention includes: an anode 3 arranged in water 2 to be treated; a cathode 4, a part of which is in contact with the water 2 to be treated and the other part of which is in contact with air; and a voltage control unit 7 connected to the anode 3 and the cathode 4 and applying a voltage for generating hydroxyl radicals on the surface of the cathode 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a microorganism adhesion prevention device, a microorganism adhesion prevention method, a wastewater treatment device, and a wastewater treatment method used for wastewater treatment.

  Some microorganisms have the ability to transfer extracellular electrons. The microorganisms generate electrons in the process while acquiring energy by oxidizing and decomposing organic substances in the liquid. In recent years, development of microbial fuel cells that use such microorganisms and recover electrons and electrical energy directly from microorganisms using an oxidation-reduction reaction by extracellular electron transfer has been promoted. The microbial fuel cell generates electric power while treating organic matter in the wastewater, and also has an effect of reducing the amount of excess sludge generated because a part of the energy used for microbial growth is used for power generation.

An invention relating to a microbial fuel cell is described in Patent Document 1, for example.
The microbial fuel cell described in Patent Document 1 has an anode (negative electrode) and a cathode (positive electrode) in a water tank that performs wastewater treatment. The anode is in the water tank, the cathode is in one side of water, and vice versa. The surface is brought into contact with air and these are connected by an external circuit. In this microbial fuel cell, microorganisms having the ability to transfer extracellular electrons are held at the anode, and metabolize using organic substances in wastewater to produce electrons and protons. Protons move to the cathode by a diffusion action based on the concentration gradient between the anode and the cathode. The electrons and protons that have moved to the cathode combine with oxygen in the air that exists in the cathode, and change to water. When these reactions occur, electrons move between the anode and the cathode, and power generation becomes possible.

  However, in a wastewater treatment apparatus to which a microbial fuel cell is applied, the microorganisms are present in inflowing wastewater and sludge, activated sludge used for wastewater treatment, and the like. In addition, the microorganism attached to or attached to the anode may peel off. These factors can cause the microorganisms to adhere to the cathode. In this case, as in the anode, the cathode collects electrons generated in the process of decomposing the organic matter. Therefore, the electrons generated in the process of decomposing the organic matter by the microorganism are similarly collected at both the anode and the cathode, and the potential difference between the anode and the cathode is eliminated. As a result, it becomes difficult to extract the power as an electric power to an external circuit. In addition, when electric power is not consumed in the external circuit, the electrical potential generated by the microorganisms must be consumed inside the treated water tank, and the reduction rate of excess sludge generation decreases, resulting in generation of excess sludge. It is conceivable that the amount is difficult to reduce. For this reason, it is important for maintaining the wastewater treatment performance that the microorganisms do not adhere to the cathode.

  In order to solve this, whenever the microorganisms adhere to the cathode and the amount of power generation decreases, the cathode to which the microorganisms have adhered is pulled out of the treated water tank and physically or chemically removed, washed, or replaced. Can be considered. However, the operation of pulling out the electrode used in the wastewater treatment apparatus is not easy, and the original wastewater treatment becomes unsatisfactory at that time.

  Under such circumstances, Non-Patent Document 1 describes that a synthetic antibacterial agent is used to inhibit microbial growth at the cathode and stabilize power generation performance.

JP2015-109288A

Weifeng Liu, Shaoan Cheng, Dan Sun, Haobin Huang, Jie Chen, Kefa Cen, `` Inhibition of microbial growth on air cathodes of single chamber microbial fuel cells by incorporating enrofloxacin into the catalyst layer '', Biosensors and Bioelectronics, Elsevier BV, 15 October 2015, Volume 72, p.44-50

  However, as described in Non-Patent Document 1, if a synthetic antibacterial agent is easily used outdoors, there is a risk of generating resistant bacteria and impairing the public health function that the wastewater treatment is responsible for. Therefore, it is desired to develop a technique that can prevent microorganisms having extracellular electron transfer ability from adhering to the cathode without using a synthetic antibacterial agent.

  The present invention has been made in view of the above circumstances, and provides a microorganism adhesion prevention device, a microorganism adhesion prevention method, a wastewater treatment apparatus, and a wastewater treatment method that can prevent microorganisms having extracellular electron transfer ability from adhering to the cathode. The task is to do.

This invention which solved the above-mentioned subject has the following composition.
The microorganism adhesion preventing apparatus according to the present invention includes an anode disposed in the water to be treated, a cathode partly in contact with the water to be treated and another part in contact with air, and connected to the anode and the cathode. And a voltage control device for applying a voltage for generating hydroxyl radicals on the surface of the cathode.

  The method for preventing microbial adhesion according to the present invention includes a voltage control device connected to an anode disposed in the water to be treated, a cathode that is partly in contact with the water to be treated, and another part that is in contact with air. A voltage for generating hydroxyl radicals is applied to the surface of the cathode.

  A wastewater treatment apparatus according to the present invention includes a treated water tank for containing treated water, an anode disposed in the treated water contained in the treated water tank, a part of which is in contact with the treated water, A cathode partially in contact with air, and a voltage control device that is connected to the anode and the cathode and applies a voltage that generates hydroxyl radicals on the surface of the cathode.

  The wastewater treatment method according to the present invention includes the anode disposed in the water to be treated, and a voltage control device connected to the cathode, part of which is in contact with the water to be treated and the other part of which is in contact with air. The water to be treated is treated by applying a voltage for generating hydroxyl radicals on the surface of the cathode.

  The microorganism adhesion prevention apparatus, microorganism adhesion prevention method, waste water treatment apparatus, and waste water treatment method according to the present invention can prevent microorganisms having extracellular electron transfer ability from adhering to the cathode.

It is a schematic block diagram explaining the structure of the waste water treatment equipment which has the microorganisms adhesion prevention apparatus which concerns on this embodiment. It is a schematic block diagram explaining the structure of the waste water treatment equipment which has the microorganisms adhesion prevention apparatus which concerns on other embodiment. It is a graph which shows the electric power generation output ratio in an Example and a comparative example.

Hereinafter, an embodiment of a microorganism adhesion prevention device, a microorganism adhesion prevention method, a wastewater treatment device, and a wastewater treatment method according to the present invention will be described in detail.
The microorganism adhesion prevention apparatus, microorganism adhesion prevention method, wastewater treatment apparatus, and wastewater treatment method according to the present embodiment are used for wastewater treatment.
Examples of the wastewater (treated water) to be treated include sewage, kitchen wastewater, miscellaneous wastewater, special wastewater, and rainwater. In the present specification, “sewage” refers to wastewater containing manure discharged from a toilet or the like. “Kitchen drainage” refers to drainage discharged from a large-scale kitchen facility. “Miscellaneous wastewater” refers to wastewater with a relatively low concentration of contaminants such as baths and washing machines. “Special wastewater” means wastewater discharged from factories, hospitals, research laboratories, and the like. “Rainwater” means rain or spring water. These wastewaters have high and low concentrations, but all contain organic matter. In addition, it is preferable that the chemical oxygen demand (COD) of waste water is about 50 to 10000 mg / L. If the COD is within this range, general biological treatment can be performed.

(Microbial adhesion prevention method, wastewater treatment method)
The microorganism adhesion prevention method according to the present embodiment includes a voltage control device connected to an anode disposed in the water to be treated, a cathode that is partly in contact with the water to be treated, and another part that is in contact with air. A voltage for generating hydroxyl radicals (.OH) is applied to the surface of the cathode.

  Moreover, the wastewater treatment method according to the present embodiment includes an anode disposed in the water to be treated, and a voltage control device connected to a cathode that is partly in contact with the water to be treated and the other part in contact with air. The treatment water is treated by applying a voltage for generating hydroxyl radicals on the surface of the cathode.

The microorganism adhesion prevention method according to the present embodiment is preferably implemented by a microorganism adhesion prevention apparatus described later. Moreover, the waste water treatment method according to the present embodiment is preferably implemented by a waste water treatment apparatus described later. That is, the definitions of terms in the microorganism adhesion prevention method, the configuration of the apparatus, and the like are synonymous with those of the microorganism adhesion prevention apparatus, and the definitions of terms in the wastewater treatment method, the configuration of the apparatus, and the like are synonymous with those of the wastewater treatment apparatus.
Hereinafter, the microorganism adhesion preventing apparatus according to the present embodiment will be described to replace the description of the microorganism adhesion preventing method according to the present embodiment. Moreover, it replaces with description of the waste water treatment method which concerns on this embodiment by demonstrating the waste water treatment apparatus which concerns on this embodiment.
Note that the microorganism adhesion prevention device and the wastewater treatment device constitute a microbial fuel cell by including treated water containing microorganisms having extracellular electron transfer capability.

(Microbe adhesion prevention device)
FIG. 1 is a schematic configuration diagram illustrating a configuration of a wastewater treatment apparatus 300 having a microorganism adhesion prevention apparatus 100 according to the present embodiment.
As shown in FIG. 1, the microorganism adhesion prevention device 100 according to the present embodiment has a configuration including an anode 3, a cathode 4, and a voltage control device 7. In the example shown in FIG. 1, the voltage control device 7 is connected to the external circuit 6 and the reference electrode 8.

  As shown in FIG. 1, the anode 3 is disposed in the treated water tank 1, specifically, the treated water 2. Microorganisms 5 having the ability to transfer extracellular electrons (hereinafter sometimes simply referred to as “microorganisms 5”) exist on the surface of the anode 3 and the periphery thereof. As the anode 3, for example, carbon fibers such as carbon felt, conductive metals such as Ti, Ti alloy, Al, Al alloy, Fe, Fe alloy, Cu, and Cu alloy are used. As long as the anode 3 can extract electricity as a microbial fuel cell, the shape and size of the anode 3 are not particularly limited. The anode 3 can be connected to a battery, a power transmission network (power system), or the like (not shown), and can supply electricity to these.

“Extracellular electron transfer capacity” refers to the ability to acquire energy necessary for life activity and transfer the generated electrons to the electron transporter existing in the cell membrane by a series of processes that oxidize and reduce the electron transporter. .
As the microorganism 5, those originally contained in the treated water 2 can be used as they are. That is, what is originally contained in the to-be-treated water 2 grows during the treatment and adheres to the surface of the anode 3 or comes to exist around the anode 3. In addition, the microorganism 5 can also use what was cultured previously.

  Specific examples of the microorganism 5 having extracellular electron transfer ability include those belonging to the genus Shewanella, those belonging to the genus Geobacter, those belonging to the genus Pseudomonas, and the genus Rhodoferax. The thing which belongs to.

Specific examples of microorganisms belonging to the genus Shewanella include S. loihica, S. oneidensis, S. putrefaciens, S. algae, etc. Is mentioned.
Specific examples of microorganisms belonging to the genus Geobacter include Geobacter sulfreduscens (G. sulfurreducens), Geobacter metallireducens (G. metallireducens) and the like.
Specific examples of microorganisms belonging to the genus Pseudomonas include P. aeruginosa.
Specific examples of microorganisms belonging to the genus Rhodoferrax include R. ferrireducens.
In addition, the microorganisms 5 which have the extracellular electron transfer capability in this embodiment do not ask | require of a wild type and a mutant type. Any microorganism can be used as the microorganism 5 as long as it can transfer electrons to the anode 3 without being limited to those described above.

  The cathode 4 performs a chemical reaction in which water is synthesized by combining electrons and protons that have moved to the cathode 4 and oxygen in the air present in the cathode 4. Therefore, a cathode 4 having oxygen permeability is used. As such a cathode 4, for example, a carbon-based material such as carbon fiber, activated carbon, graphite, carbon black, or carbon nanotube can be used. The carbon-based material is preferably coated with conductive metal particles (catalyst) such as Pt, Pt alloy, Au, and Au alloy because the above-described chemical reaction is promoted.

  In the case of this embodiment, a part of the cathode 4 is in contact with the treated water 2 and the other part is in contact with air. Preferably, as shown in FIG. 1, the cathode 4 is provided on the wall of the treated water tank 1 with one surface exposed to the inside of the treated water tank 1 and the other surface exposed to the outside of the treated water tank 1. It has been. If it does in this way, air can be taken in from the other surface, performing the chemical reaction which synthesize | combines water mentioned above by the one surface of the cathode 4. FIG.

  The voltage control device 7 includes an external circuit 6 and an external power source (not shown). The voltage control device 7 is connected to the anode 3 and the cathode 4 and applies a voltage for generating hydroxyl radicals on the surface of the cathode 4. The hydroxyl radical is a kind of active oxygen species and has an unpaired electron, so it is also called a free radical. The hydroxyl radical is very reactive among reactive oxygen species and oxidizes biological components such as proteins, lipids, carbohydrates, and nucleic acids. Therefore, the microorganism 5 in contact with the hydroxyl radical is inhibited in activity or sterilized because the cell wall or cell membrane is denatured or the nucleic acid is damaged. Therefore, it is possible to prevent the microorganisms 5 having an extracellular electron transfer capability from adhering to the cathode 4.

  That is, in this embodiment, the electron production ability of the microorganisms 5 growing on the surface of the anode 3 is effectively utilized, and further, the hydroxyl radical generation reaction is controlled using the voltage controller 7.

In a general microbial fuel cell cathode reaction, four electrons supplied from the anode 4 react with one molecule of oxygen to produce four hydroxide ions. And finally, it reacts with protons and neutralizes to water (4-electron reduction reaction, see the following reaction formula (1)).

O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (1)

On the other hand, in this embodiment, as shown in the following reaction formulas (2) and (3), a three-electron reduction reaction is performed on the surface of the cathode 4 to generate hydroxyl radicals having oxidizing and sterilizing power. Then, the generated hydroxyl radical suppresses or prevents the microorganism 5 from adhering to the surface of the cathode 4, and further inhibits or sterilizes the activity of the attached microorganism 5. Since hydroxyl radicals have unpaired electrons and are generally unstable, they react with organic foreign substances adhering to the surface of the cathode 4 and are consumed quickly, so there is no persistence. Therefore, there is no worry of inducing resistant bacteria like antibacterial agents. Furthermore, the organic foreign matter that has reacted with the hydroxyl radical is hydrophilized, and the molecular chain is cleaved to reduce the molecular weight and be dissolved and removed. As a result, the effect of reducing the amount of excess sludge generation is obtained.

O ₂ ⁻ + 2H ⁺ + 2e ⁻ → H ₂ O ₂ (2) (2-electron reduction reaction)

H ₂ O ₂ + e ⁻ → OH ⁻ + · OH (3) (3-electron reduction reaction)

  In the present embodiment, the chemical reaction according to the reaction formulas (2) and (3) may be obtained, and the reaction formula (1) may proceed simultaneously. The voltage applied by the voltage control device 7 varies depending on the configuration of the cathode 4, such as the material of the cathode 4 to be used, the presence / absence of a catalyst used in the cathode 4, and the type of catalyst. Therefore, we conduct experiments in advance, measure the characteristics when oxygen molecules are electrochemically reduced, proceed with reaction formulas (2) and (3), and measure the potential for generating hydroxyl radicals. Is preferably set to a desired cathode electrode potential. For example, when a carbon-based material coated with a Pt-based catalyst is used, the voltage applied by the voltage control device 7 is preferably 0.1 to 2.6 V, for example, 0 More preferably, it is set to 7V. When a voltage is applied to the cathode 4 at the voltage value, a three-electron reduction reaction can be performed. Thus, in this embodiment, the reduction reaction is controlled by applying an external voltage using the voltage control device 7. That is, the voltage applied to the cathode 4 is controlled from the outside so as to be a voltage (approximately 0.7 V vs SHE) necessary for causing a three-electron reduction reaction that generates hydroxyl radicals. SHE is an abbreviation for Standard Hydrogen Electrode.

  The voltage described above can be applied constantly or in a timely manner during waste water treatment. When the above-described voltage is always applied, the microorganisms 5 can always be prevented from adhering to the cathode 4. In addition, when the voltage described above is applied in a timely manner, if the amount of the microorganisms 5 attached to the cathode 4 increases, the microorganism 5 can be sterilized by applying the voltage described above, thereby preventing the microorganisms 5 from attaching to the cathode 4. . In this case, power consumption by the voltage control device 7 can be suppressed. In the present embodiment, the electrode potential of the cathode 4 may be adjusted when the activity of the microorganism 5 at the anode 3 is low. If it does in this way, the oxygen concentration in the to-be-processed water 2 can be reduced, the to-be-processed water 2 can be kept anaerobically, and the activity of the microorganisms 5 can be raised.

  The amount of the microorganisms 5 attached to the cathode 4 can be grasped by measuring the amount of power generated by the microorganism fuel cell. That is, if the amount of microorganisms 5 attached to the cathode 4 is small, the amount of power generation increases, and if the amount of microorganisms 5 attached to the cathode 4 is large, the amount of power generation decreases. The “timely” in this embodiment includes not only applying the voltage described above at an appropriate timing based on the amount of power generation, but also applying the voltage described above for a fixed time at a fixed time interval. It is. When the voltage of the cathode 4 is controlled in a timely manner, it can be implemented by operating the voltage control device 7 by a program or the like, but can also be arbitrarily implemented by manual operation.

As shown in FIG. 1, the voltage control device 7 preferably includes a Vc measurement external circuit 9. The Vc measurement external circuit 9 is connected to the reference electrode 8 and the cathode 4 arranged in the water 2 to be treated, and has a Vc control external circuit 10 at an arbitrary position on the circuit connecting them. The Vc control external circuit 10 is connected to the voltage control device 7. The Vc control external circuit 10 feedback-controls the voltage control device 7 according to the cathode electrode potential Vc measured by the reference electrode 8 and the Vc measurement external circuit 9. That is, the voltage control device 7 includes the Vc control external circuit 10 so that the potential of the cathode 4 can be accurately grasped and the load of the external circuit 6 can be arbitrarily adjusted. Can be done.
In the feedback control, for example, if the voltage value of the cathode 4 measured by the reference electrode 8 or the like is lower than a preset set value, the resistance value is increased (current value is decreased) and the voltage value is increased. If the value is higher than the set value, the resistance value is decreased (the current value is increased) to decrease the voltage value.

  As the voltage control device 7 having the reference electrode 8, the Vc measurement external circuit 9 that performs feedback control, and the Vc control external circuit 10, for example, a potentiostat that is commercially available for electrochemical reaction control is preferably used. it can. When a potentiostat is not used, a similar device can be configured by combining the external circuit 6, the Vc measurement external circuit 9, and the Vc control external circuit 10 as shown in FIG.

  The microorganism adhesion preventing apparatus 100 having such a configuration uses the voltage control device 7 connected to the external circuit 6 to control the voltage applied to both ends of the external circuit 6, that is, the anode 3 and the cathode 4, at all times or in a timely manner. By carrying out (on a regular basis), the cathode electrode potential Vc is indirectly maintained at a constant value. In this state, the microorganisms 5 attached to the anode 3 metabolize the organic matter in the water to be treated 2 supplied to the treated water tank 1. Electrons generated in the process of metabolizing organic matter reach the cathode 4 via the external circuit 6, and the circuit of the microbial fuel cell is established based on the principle described above.

At this time, although the reaction formula (1) proceeds in the conventional microbial fuel cell, in this embodiment, the voltage applied to the cathode 4 is adjusted using the voltage control device 7 installed in the external circuit 6. The reaction formulas (2) and (3) proceed, and hydroxyl radicals are generated on the surface of the cathode 4 and around it. Since the activity of the microorganism 5 is inhibited or sterilized by the generated hydroxyl radical, the microorganism 5 can be prevented from adhering to the cathode 4.
Further, the hydroxyl radical generated in this way reacts with the organic foreign matter adhering to the surface of the cathode 4 and is dissolved and removed as described above. Therefore, resistance between the to-be-processed water 2 and the cathode 4 and between the anode 3 and the cathode 4 is reduced. As a result, surplus electrons generated during the organic substance treatment by the microorganism 5 at the anode 3 can be efficiently consumed, and the activity level of the microorganism 5 and other accompanying performance can be maintained high and stably. it can.

(Wastewater treatment equipment)
Next, the waste water treatment apparatus according to the present embodiment will be described with reference to FIG.
As shown in FIG. 1, the wastewater treatment apparatus 300 according to the present embodiment includes the microorganism adhesion preventing apparatus 100 according to the present embodiment. That is, the waste water treatment apparatus 300 includes the treated water tank 1 having the anode 3, the cathode 4, and the voltage control device 7 that are components of the microorganism adhesion prevention apparatus 100.

  The treatment tank 1 may be a general one used for waste water treatment, but as described above, it is preferable that the cathode 4 is provided on at least a part of the wall portion. Since the anode 3, the cathode 4, and the voltage control device 7 are the same as described above, detailed description thereof is omitted.

  Supply of the to-be-processed water 2 to the treated water tank 1 may be performed continuously using a pump etc. which are not illustrated, and may be performed batchwise. The amount of water in the treated water tank 1 is preferably set so that the anode 3 is immersed in the treated water 2. The treated water treated in the treated water tank 1 is discharged out of the treated water tank 1 from a discharge port (not shown).

(Other embodiments)
The microorganism adhesion preventing apparatus according to the present embodiment can be applied not only to a newly constructed wastewater treatment apparatus, but also can be used to retrofit or retrofit an existing wastewater treatment apparatus.
When retrofitting the microbial adhesion preventing apparatus according to the present embodiment to a wastewater treatment apparatus, for example, as shown in FIG. 2, instead of providing the cathode on the wall of the treated water tank, an air tank 41 having a cathode 4 is provided. It can be provided in the treated water 2. FIG. 2 is a schematic configuration diagram illustrating a configuration of a wastewater treatment apparatus 400 including the microorganism adhesion prevention apparatus 200 according to another embodiment.

  The air tank 41 is provided with a cathode 4 on a part or all of the wall portion so that one surface is in contact with the water to be treated 2 and the other surface is in contact with air. The upper part of the air tank 41 shown in FIG. 2 is opened, and the inner side 42 can freely enter and exit air from this opening. Therefore, the cathode 4 of the microorganism adhesion preventing apparatus 200 can take in air from the other surface while performing the above-described chemical reaction on one surface, and can advance the reaction formulas (2) and (3). it can. Therefore, this microorganism adhesion preventing apparatus 200 can also prevent microorganisms 5 from adhering to the cathode 4. The air tank 41 is preferably provided with a blower fan that sends air into the inner side 42 and an exhaust fan (none of which is shown) that discharges air inside the inner side 42, because sufficient oxygen can be supplied to the inner side 42. .

Next, a confirmation experiment for confirming the effect of the present invention will be described.
An anode, a cathode, a reference electrode, and three external circuits connecting them were installed in a treated water tank having a water tank volume of 25 L. A carbon felt was used for the anode, and a carbon-based material coated with a Pt-based catalyst was used for the cathode.
The first external circuit is a high impedance circuit that is provided between the cathode and the reference electrode and measures a potential difference (cathode electrode potential Vc) between the two.
The second external circuit is a circuit for connecting the anode and the cathode and consuming surplus electrons generated at the anode at the cathode.
In addition, a voltage control device that refers to the value of the cathode electrode potential Vc measured in the first external circuit and controls the voltage applied to both ends of the second external circuit so that the Vc value becomes a desired value. A third external circuit (a feedback control circuit using an operational amplifier) was also installed.
In this embodiment, a potentiostat is used as a unit formed by combining the first, second, and third external circuits.
Public sewage was used as organic matter-containing wastewater, and the organic matter concentration was 50 to 100 mg / L in terms of COD.

  Since the hydroxyl radical generation potential of the cathode used in this example is 0.7 V, the desired cathode electrode potential Vc is set to 0.7 V, and the potentiostat is set so that the cathode electrode potential Vc is 0.7 V. Drove.

As a result, using the function of the third external circuit and continuing the operation while controlling the cathode electrode potential Vc to be 0.7 V, it was confirmed that no foreign matter adhered to the cathode surface. (Example).
On the other hand, when the function of the third external circuit was stopped and the feedback control of the cathode electrode potential Vc was stopped, it was confirmed that the foreign matter was remarkably adhered to the cathode surface (comparative example). In addition, the said foreign material contained the microorganisms which have extracellular electron transfer.

  In addition, the effect that foreign matter did not adhere to the cathode surface also appeared in the output of the microbial fuel cell. Specifically, the power generation output taken out as an external output to the second external circuit formed by connecting the anode and the cathode is operated when using the function of the third external circuit (Example) and When the operation was performed without using the external circuit 3 (comparative example), the difference was greatly different. The result is shown in FIG. In addition, FIG. 3 is a graph which shows the power generation output ratio in an Example and a comparative example. As shown in FIG. 3, the power generation output of the example increased 5 times or more compared to the comparative example.

  As described above, the microorganism adhesion preventing apparatus, the microorganism adhesion preventing method, the wastewater treatment apparatus, and the wastewater treatment method according to the present invention have been described in detail with reference to the embodiments and examples. However, the present invention is limited to the above-described embodiments and examples. It is not a thing and various modifications are included. For example, the above-described embodiments and examples have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of an embodiment or example can be replaced with the configuration of another embodiment or example, and the configuration of another embodiment or example can be replaced with that of another embodiment or example. It is also possible to add a configuration. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment or example.

1 treated water tank 2 treated water (drainage)
3 Anode 4 Cathode 5 Microorganism (microorganism having extracellular electron transfer ability)
6 External circuit 7 Voltage control device 8 Reference electrode 9 Vc measurement external circuit 10 Vc control external circuit 100, 200 Microbe adhesion prevention device 300, 400 Wastewater treatment device

Claims (6)

An anode disposed in the water to be treated;
A cathode partly in contact with the treated water and the other part in contact with air;
A voltage control device that is connected to the anode and the cathode and applies a voltage for generating hydroxyl radicals on the surface of the cathode;
A device for preventing microbial adhesion, comprising: In claim 1,
The microorganism adhesion prevention device, wherein the voltage is 0.7V. In claim 1,
A microorganism adhesion preventing apparatus characterized by applying the voltage constantly or in a timely manner.   Hydroxyl radicals are generated on the surface of the cathode by a voltage control device connected to an anode disposed in the water to be treated and a cathode partly in contact with the water to be treated and the other part in contact with air. A method for preventing microorganism adhesion, which comprises applying a voltage. A treated water tank for storing the treated water;
An anode disposed in the treated water stored in the treated water tank;
A cathode partly in contact with the treated water and the other part in contact with air;
A voltage control device that is connected to the anode and the cathode and applies a voltage for generating hydroxyl radicals on the surface of the cathode;
A wastewater treatment apparatus comprising:   Hydroxyl radicals are generated on the surface of the cathode by a voltage control device connected to an anode disposed in the water to be treated and a cathode partly in contact with the water to be treated and the other part in contact with air. A wastewater treatment method, wherein a voltage is applied to treat the treated water.

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