WO2019078002A1

WO2019078002A1 - Liquid processing system

Info

Publication number: WO2019078002A1
Application number: PCT/JP2018/036985
Authority: WO
Inventors: 直毅吉川
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2017-10-18
Filing date: 2018-10-03
Publication date: 2019-04-25

Abstract

A liquid processing system (100, 100A) comprises a processing tank (70) that retains a liquid (60) to be processed including an organic substance, and has an inlet (71) and an outlet (72) for the liquid to be processed. The liquid processing system further comprises one or more electrode units (1) that are provided inside the processing tank and are arranged along a direction from the inlet to the outlet in planar view. Additionally, the liquid processing system comprises a three-dimensional structure (90) that is provided between the electrode unit(s) and the processing tank, and/or between neighboring electrode units. Each electrode unit comprises a negative electrode (20) that supports microorganisms, and a positive electrode (10) that is electrically connected to the negative electrode, wherein the negative electrode and the positive electrode are immersed in the liquid to be processed, and at least one section of the positive electrode is exposed to a gas phase (2).

Description

Liquid treatment system

The present invention relates to liquid processing systems. In particular, the present invention relates to a liquid treatment system using a microbial fuel cell capable of purifying wastewater and producing electrical energy.

In recent years, microbial fuel cells that generate electricity using biomass have attracted attention as sustainable energy. A microbial fuel cell is a wastewater treatment device that oxidizes and processes organic substances and nitrogen-containing compounds while converting the chemical energy of organic substances and nitrogen-containing compounds contained in domestic wastewater and industrial wastewater into electrical energy. . And a microbial fuel cell has the characteristics of little generation | occurence | production of a sludge, and also energy consumption is small.

A microbial fuel cell has a negative electrode carrying a microorganism, and a positive electrode in contact with a gas phase containing oxygen and an electrolytic solution. And while supplying the electrolyte solution containing an organic substance etc. to a negative electrode, the gas containing oxygen is supplied to a positive electrode. The negative electrode and the positive electrode form a closed circuit by being connected to each other through a load circuit. At the negative electrode, hydrogen ions and electrons are generated from the electrolytic solution by the 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 to be consumed as water. At that time, the electrical energy flowing to the closed circuit is recovered.

As a conventional waste water treatment apparatus, there is provided a container provided with a waste water inlet and outlet, and a microbial fuel comprising a plurality of electrode units arranged in the container along a direction from the inlet to the outlet. A battery wastewater treatment system is disclosed (see, for example, Patent Document 1). And in patent document 1, since several electrode units are arranged along the direction which goes to an outflow port from an inflow port, the organic substance density | concentration in wastewater becomes equivalent in any of several electrode units, and an electrode unit It is described that the amount of power generation per hit is uniform.

JP, 2016-147227, A

However, in Patent Document 1, since the waste water flows between the plurality of electrode units arranged along the direction from the inlet to the outlet, the waste water may not easily contact the surface of the electrode unit. Therefore, there is a problem that the contact between the microorganism carried on the electrode unit and the wastewater becomes insufficient, and the microorganism does not act efficiently.

The present invention has been made in view of the problems of the prior art. And the object of the present invention is to provide a liquid treatment system capable of enhancing the contact between the electrode unit and the wastewater and efficiently performing the power generation by microorganisms and the purification of the wastewater.

In order to solve the above problems, a liquid treatment system according to an aspect of the present invention holds a liquid to be treated containing an organic substance, and has a treatment tank having an inlet and an outlet for the treatment liquid, and the inside of the treatment tank. And one or more electrode units provided along the direction from the inlet to the outlet in plan view, at least between the electrode unit and the processing tank, and between the adjacent electrode units. And a three-dimensional structure provided on one side. The electrode unit includes a negative electrode supporting a microorganism and a positive electrode electrically connected to the negative electrode, the negative electrode and the positive electrode being immersed in the liquid to be treated, and at least a part of the positive electrode is exposed to the gas phase.

FIG. 1 is a schematic perspective view showing an example of a liquid processing system according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a schematic plan view showing an example of the liquid processing system according to the embodiment of the present invention. FIG. 4 is an exploded perspective view showing an electrode unit in the liquid processing system. FIG. 5 is a schematic plan view showing another example of the liquid treatment system according to the embodiment of the present invention. FIG. 6 is a schematic plan view showing another example of the liquid treatment system according to the embodiment of the present invention. FIG. 7 is a cross-sectional view taken along the line BB in FIG. FIG. 8 is a cross-sectional view along the line CC in FIG. FIG. 9 is a graph showing the relationship between the steady-state output and the number of working days in the liquid treatment system of the example and the comparative example.

Hereinafter, the liquid processing system according to the present embodiment will be described in detail. The dimensional ratios in the drawings are exaggerated for the convenience of description, and may differ from the actual ratios.

As shown in FIG. 1, the liquid processing system 100 according to the present embodiment includes an electrode unit 1 having a positive electrode 10, a microorganism, and a negative electrode 20 electrically connected to the positive electrode 10. The liquid processing system 100 further includes a processing tank 70 which holds the liquid to be treated 60 containing an organic substance inside and further immerses the electrode unit 1 in the liquid to be treated 60.

[Electrode unit]
The electrode unit 1 includes an electrode assembly 40 composed of a positive electrode 10, a negative electrode 20, and an ion transfer layer 30, as shown in FIGS. In the electrode unit 1, the negative electrode 20 is disposed in contact with one surface 30 a of the ion transfer layer 30, and the positive electrode 10 is disposed in contact with the surface 30 b opposite to the surface 30 a of the ion transfer layer 30. ing. The gas diffusion layer 12 of the positive electrode 10 is in contact with the ion transfer layer 30, and the water repellent layer 11 is exposed to the gas phase 2 side.

And as shown in FIG. 4, the electrode assembly 40 is laminated | stacked on the cassette base material 50. As shown in FIG. The cassette base 50 is a U-shaped frame member along the outer peripheral portion of the surface 10 a of the positive electrode 10, and the upper portion is open. That is, the cassette base 50 is a frame member in which the bottom surfaces of the two first columnar members 51 are connected by the second columnar member 52. Then, as shown in FIG. 2, the side surface 53 of the cassette base 50 is joined to the outer peripheral portion of the surface 10 a of the positive electrode 10.

As shown in FIG. 2, an electrode unit 1 formed by laminating two sets of electrode assemblies 40 and a cassette base 50 is formed inside the processing tank 70 so that the gas phase 2 communicated with the atmosphere is formed. Be placed. A liquid to be treated 60, which is a waste water, is held inside the treatment tank 70, and the gas diffusion layer 12, the negative electrode 20 and the ion transfer layer 30 of the positive electrode 10 are immersed in the liquid to be treated 60.

As described later, the positive electrode 10 is provided with a water repellent layer 11 having water repellency. Therefore, the liquid to be treated 60 held inside the treatment tank 70 and the inside of the cassette base 50 are separated, and the internal space formed by the electrode assembly 40 and the cassette base 50 is the gas phase 2 . Then, in the liquid processing system 100, the gas phase 2 is opened to the outside air, or air is supplied to the gas phase 2 from the outside, for example, by a pump. Further, as shown in FIG. 2, the positive electrode 10 and the negative electrode 20 are each electrically connected to the external circuit 80.

(Positive electrode)
As shown in FIG. 2, the positive electrode 10 according to the present embodiment is a gas diffusion electrode including a water repellent layer 11 and a gas diffusion layer 12 stacked so as to be in contact with the water repellent layer 11. By using such a thin plate-like gas diffusion electrode, it is possible to easily supply the oxygen in the gas phase 2 to the catalyst in the positive electrode 10.

<Water-repellent layer>
The water repellent layer 11 in the positive electrode 10 is a layer having both water repellency and oxygen permeability. The water repellent layer 11 is configured to allow the movement of oxygen from the gas phase 2 to the liquid phase while satisfactorily separating the gas phase 2 and the liquid phase in the electrochemical system in the electrode unit 1. That is, while the water repellent layer 11 allows oxygen in the gas phase 2 to permeate and move to the gas diffusion layer 12, the liquid 60 can be inhibited from moving to the gas phase 2 side. Here, “separation” means to physically shut off.

The water repellent layer 11 is in contact with the gas phase 2 containing oxygen and diffuses the oxygen in the gas phase 2. The water repellent layer 11 supplies oxygen to the gas diffusion layer 12 substantially uniformly in the configuration shown in FIG. Therefore, it is preferable that the water repellent layer 11 be a porous body so that the oxygen can be diffused. In addition, since the water repellent layer 11 has water repellency, it is possible to prevent the pores of the porous body from being blocked by condensation or the like and the decrease in the diffusion of oxygen being suppressed. Further, since the liquid 60 to be treated is difficult to permeate into the water repellent layer 11, oxygen can be efficiently circulated from the surface of the water repellent layer 11 in contact with the gas phase 2 to the surface facing the gas diffusion layer 12. It becomes possible.

The water repellent layer 11 is preferably formed in a sheet shape. Further, the material constituting the water repellent layer 11 is not particularly limited as long as it has water repellency and oxygen in the gas phase 2 can be diffused. The material constituting the water repellent layer 11 is made of, for example, polyethylene, polypropylene, polybutadiene, nylon, polytetrafluoroethylene (PTFE), ethylcellulose, poly-4-methylpentene-1, butyl rubber and polydimethylsiloxane (PDMS). At least one selected from the group can be used. Since these materials easily form a porous body and also have high water repellency, it is possible to suppress clogging of pores and improve gas diffusivity. The water repellent layer 11 preferably has a plurality of through holes in the stacking direction Z of the water repellent layer 11 and the gas diffusion layer 12.

As the water repellent layer 11, for example, a waterproof moisture permeable sheet can be used. As the waterproof moisture-permeable sheet, for example, Cellpore (registered trademark) manufactured by Sekisui Chemical Co., Ltd. and Breslon (registered trademark) manufactured by Nitoms Corporation can be used.

The water repellent layer 11 may be subjected to a water repellent treatment using a water repellent, if necessary, in order to enhance the water repellency. Specifically, a water repellent agent such as polytetrafluoroethylene may be attached to the porous body constituting the water repellent layer 11 to improve the water repellency.

<Gas diffusion layer>
The gas diffusion layer 12 in the positive electrode 10 preferably includes a porous conductive material and a catalyst supported on the conductive material. The gas diffusion layer 12 may be made of a porous and conductive catalyst. By providing such a gas diffusion layer 12 on the positive electrode 10, it becomes possible to conduct electrons generated by a local cell reaction described later between the catalyst and the external circuit 80. That is, as described later, a catalyst is supported on the gas diffusion layer 12, and the catalyst is an oxygen reduction catalyst. Then, the electrons move from the external circuit 80 to the catalyst through the gas diffusion layer 12 so that the catalyst can promote the oxygen reduction reaction by oxygen, hydrogen ions and electrons.

In the positive electrode 10, in order to ensure stable performance, it is preferable that oxygen permeates the water repellent layer 11 and the gas diffusion layer 12 efficiently and is supplied to the catalyst. Therefore, the gas diffusion layer 12 is preferably a porous body having a large number of pores through which oxygen can permeate from the surface facing the water repellent layer 11 to the surface on the opposite side. Further, the shape of the gas diffusion layer 12 is particularly preferably a three-dimensional mesh shape. With such a mesh shape, it is possible to impart high oxygen permeability and conductivity to the gas diffusion layer 12.

In the positive electrode 10, in order to supply oxygen to the gas diffusion layer 12 efficiently, the water repellent layer 11 is preferably joined to the gas diffusion layer 12 via an adhesive. Thus, the diffused oxygen is directly supplied to the gas diffusion layer 12, and the oxygen reduction reaction can be efficiently performed. The adhesive is preferably provided at least in part between the water repellent layer 11 and the gas diffusion layer 12 from the viewpoint of securing the adhesiveness between the water repellent layer 11 and the gas diffusion layer 12. However, from the viewpoint of enhancing adhesion between the water repellent layer 11 and the gas diffusion layer 12 and supplying oxygen to the gas diffusion layer 12 stably over a long period, the adhesive is the water repellent layer 11 and the gas diffusion layer More preferably, it is provided on the entire surface between 12 and 12.

The adhesive is preferably one having oxygen permeability, and includes at least one selected from the group consisting of polymethyl methacrylate, methacrylic acid-styrene copolymer, styrene-butadiene rubber, butyl rubber, nitrile rubber, chloroprene rubber and silicone. Resin can be used.

Here, the gas diffusion layer 12 of the positive electrode 10 in the present embodiment will be described in more detail. As described above, the gas diffusion layer 12 can be configured to include a porous conductive material and a catalyst supported on the conductive material.

The conductive material in the gas diffusion layer 12 can be made of, for example, one or more materials selected from the group consisting of carbon-based materials, conductive polymers, semiconductors, and metals. Here, the carbon-based substance refers to a substance having carbon as a component. Examples of carbon-based materials include, for example, graphite, activated carbon, carbon black, Vulcan (registered trademark) XC-72R, acetylene black, carbon powder such as furnace black and denka black, graphite felt, carbon wool, carbon woven fabric, etc. Carbon fiber, carbon plate, carbon paper, carbon disk, carbon cloth, carbon foil, carbon-based material obtained by compression molding of carbon particles can be mentioned. In addition, as an example of the carbon-based material, fine structure materials such as carbon nanotubes, carbon nanohorns, and carbon nanoclusters can also be mentioned. Furthermore, as the conductive material in the gas diffusion layer 12, metal materials such as mesh and foam can also be used.

The conductive polymer is a generic term for polymer compounds having conductivity. As the conductive polymer, for example, a single monomer or a polymer of two or more monomers having aniline, aminophenol, diaminophenol, pyrrole, thiophene, paraphenylene, fluorene, furan, acetylene or derivatives thereof as a constitutional unit It can be mentioned. Specifically, examples of the conductive polymer include polyaniline, polyaminophenol, polydiaminophenol, polypyrrole, polythiophene, polyparaphenylene, polyfluorene, polyfuran, polyacetylene and the like. As a metal conductive material, a stainless steel mesh is mentioned, for example. In consideration of availability, cost, corrosion resistance, durability and the like, the conductive material is preferably a carbon-based material.

In addition, the shape of the conductive material is preferably a powder shape or a fiber shape. In addition, the conductive material may be supported by a support. The support refers to a member which itself is rigid and can give the gas diffusion electrode a certain shape. The support may be an insulator or a conductor. When the support is an insulator, examples of the support include glass, plastic, synthetic rubber, ceramics, paper treated with water or water resistance, water repellent or water repellent, plant pieces such as wood pieces, bone pieces, animal pieces such as shells, etc. . Examples of the support having a porous structure include porous ceramic, porous plastic, sponge and the like. When the support is a conductor, examples of the support include carbon paper, carbon fibers, carbon-based materials such as carbon rods, metals, conductive polymers, and the like.

The catalyst in the gas diffusion layer 12 is a platinum-based catalyst, a carbon-based catalyst using iron or cobalt, a transition metal oxide-based catalyst such as partially oxidized tantalum carbonitride (TaCNO) or zirconium carbonitride (ZrCNO), tungsten Alternatively, a carbide-based catalyst using molybdenum, activated carbon or the like can be used.

The catalyst in the gas diffusion layer 12 is preferably a carbon-based material doped with metal atoms. The metal atom is not particularly limited, but titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, hafnium, tantalum, tungsten, rhenium, osmium, iridium It is preferable that it is an atom of at least one metal selected from the group consisting of platinum and gold. In this case, the carbon-based material exhibits excellent performance as a catalyst for particularly promoting the oxygen reduction reaction. The amount of metal atoms contained in the carbon-based material may be appropriately set so that the carbon-based material has excellent catalytic performance.

The carbon-based material is preferably further doped with one or more nonmetallic atoms selected from nitrogen, boron, sulfur and phosphorus. The amount of nonmetal atoms doped in the carbon-based material may also be appropriately set so that the carbon-based material has excellent catalytic performance.

The carbon-based material is based on a carbon source material such as graphite and amorphous carbon, and the carbon source material is doped with metal atoms and one or more nonmetal atoms selected from nitrogen, boron, sulfur and phosphorus It is obtained by

The combination of metal atoms and nonmetal atoms doped in the carbon-based material is appropriately selected. In particular, it is preferable that the nonmetal atom contains nitrogen and the metal atom contains iron. In this case, the carbon-based material can have particularly excellent catalytic activity. The nonmetal atom may be only nitrogen or the metal atom may be only iron.

The nonmetal atom may contain nitrogen, and the metal atom may contain at least one of cobalt and manganese. Also in this case, the carbon-based material can have particularly excellent catalytic activity. The nonmetal atom may be only nitrogen. In addition, the metal atom may be only cobalt, only manganese, or only cobalt and manganese.

The shape of the carbon-based material is not particularly limited. For example, the carbon-based material may have a particulate shape or may have a sheet-like shape. The dimensions of the carbon-based material having a sheet-like shape are not particularly limited, and, for example, the carbon-based material may have minute dimensions. The carbonaceous material having a sheet-like shape may be porous. It is preferable that the porous carbon-based material having a sheet-like shape has, for example, a woven-like shape, a non-woven-like shape or the like. Such a carbon-based material can constitute the gas diffusion layer 12 even without the conductive material.

The carbon-based material configured as a catalyst in the gas diffusion layer 12 can be prepared as follows. First, a mixture containing, for example, a nonmetal compound containing at least one nonmetal selected from the group consisting of nitrogen, boron, sulfur, and phosphorus, a metal compound, and a carbon source material is prepared. Then, the mixture is heated at a temperature of 800 ° C. or more and 1000 ° C. or less for 45 seconds or more and less than 600 seconds. Thereby, a carbon-based material configured as a catalyst can be obtained.

Here, as the carbon source material, as described above, for example, graphite or amorphous carbon can be used. Further, the metal compound is not particularly limited as long as it is a compound containing a metal atom which can coordinately bond with a nonmetal atom doped in the carbon source material. Examples of metal compounds include inorganic metal salts such as metal chlorides, nitrates, sulfates, bromides, iodides and fluorides, organic metal salts such as acetates, hydrates of inorganic metal salts, and organic metal salts It is possible to use at least one selected from the group consisting of hydrates of For example, when graphite is doped with iron, the metal compound preferably contains iron (III) chloride. In addition, when graphite is doped with cobalt, the metal compound preferably contains cobalt chloride. When manganese is doped to the carbon source material, the metal compound preferably contains manganese acetate. The amount of the metal compound used is preferably determined so that, for example, the ratio of metal atoms in the metal compound to the carbon source material is in the range of 5 to 30% by mass, and this ratio is further preferably 5 to 20% by mass More preferably, it is determined to be within the range.

The nonmetallic compound is preferably at least one nonmetallic compound selected from the group consisting of nitrogen, boron, sulfur and phosphorus as described above. Examples of nonmetal compounds include pentaethylenehexamine, ethylenediamine, tetraethylenepentamine, triethylenetetramine, octylboronic acid, 1,2-bis (diethylphosphinoethane), triphenyl phosphite, and benzyl disulfide. At least one compound selected from the group consisting of The amount of the nonmetallic compound used is appropriately set according to the doping amount of the nonmetallic atom to the carbon source material. The amount of the nonmetallic compound used is preferably determined such that the molar ratio of the metal atom in the metallic compound to the nonmetallic atom in the nonmetallic compound is in the range of 1: 1 to 1: 2. More preferably, it is determined to be in the range of 1: 1.5 to 1: 1.8.

In the gas diffusion layer 12, the catalyst may be bound to the conductive material using a binder. That is, the catalyst may be supported on the surface of the conductive material and inside the pores using a binder. Thereby, the catalyst can be prevented from being desorbed from the conductive material and the oxygen reduction characteristics can be prevented from being degraded. As the binder, for example, it is preferable to use at least one selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride (PVDF), and ethylene-propylene-diene copolymer (EPDM). It is also preferable to use NAFION (registered trademark) as a binder.

(Negative electrode)
The negative electrode 20 according to the present embodiment has a function of supporting the below-described microorganism and generating hydrogen ions and electrons from at least one of the organic substance and the nitrogen-containing compound in the liquid 60 by catalytic action of the microorganism. . Therefore, the negative electrode 20 is not particularly limited as long as it has a configuration that produces such a function.

The negative electrode 20 has a structure in which microorganisms are supported on a conductive sheet having conductivity. As the conductive sheet, at least one selected from the group consisting of a porous conductive sheet, a woven conductive sheet and a non-woven conductive sheet can be used. The conductor sheet may be a laminate in which a plurality of sheets are laminated. By using a sheet having such a plurality of pores as the conductive sheet of the negative electrode 20, hydrogen ions generated by the later-described local cell reaction easily move in the direction of the ion transfer layer 30, and the oxygen reduction reaction It is possible to increase the speed. Further, from the viewpoint of improving ion permeability, the conductor sheet of the negative electrode 20 has a space (void) continuous in the stacking direction Z of the positive electrode 10, the ion transfer layer 30, and the negative electrode 20, that is, the thickness direction. Is preferred.

The conductor sheet may be a metal plate having a plurality of through holes in the thickness direction. Therefore, as a material constituting the conductive sheet of the negative electrode 20, for example, at least one selected from the group consisting of conductive metals such as aluminum, copper, stainless steel, nickel and titanium, carbon paper, and carbon felt is used. be able to.

A graphite sheet may be used as the conductive sheet of the negative electrode 20. Further, it is preferable that the negative electrode 20 contains graphite, and the graphene layers in the graphite be arranged along a plane in a direction XY perpendicular to the stacking direction Z of the positive electrode 10, the ion transfer layer 30, and the negative electrode 20. By arranging the graphene layers in this manner, the conductivity in the direction XY perpendicular to the stacking direction Z is improved more than the conductivity in the stacking direction Z. Therefore, the electrons generated by the local cell reaction of the negative electrode 20 can be easily conducted to the external circuit 80, and the efficiency of the cell reaction can be further improved.

The microorganism carried on the negative electrode 20 is not particularly limited as long as it is a microorganism that decomposes the organic substance or the nitrogen-containing compound in the liquid to be treated 60 to generate hydrogen ions and electrons. As such a microorganism, for example, an aerobic microorganism that requires oxygen for growth or an anaerobic microorganism that does not require oxygen for growth can be used, but it is preferable to use an anaerobic microorganism. Anaerobic microorganisms do not require air for oxidatively decomposing organic substances in the liquid 60 to be treated. Therefore, the power required to feed the air can be significantly reduced. In addition, since the free energy obtained by microorganisms is small, it is possible to reduce the amount of sludge generated.

When the microorganism carried on the negative electrode 20 is an anaerobic microorganism, it is preferable to keep the periphery of the negative electrode 20 in an anaerobic atmosphere in order to enhance the activity of the anaerobic microorganism.

Examples of aerobic microorganisms retained on the negative electrode 20 include E. coli, which is an Escherichia bacteria, P. pneumoniae, which is a Pseudomonas bacteria, and B. subtilis, which is a Bacillus bacteria. Moreover, it is preferable that the anaerobic microorganisms hold | maintained at the negative electrode 20 are electric production bacteria which have an extracellular electron transfer mechanism, for example. Specifically, examples of anaerobic microorganisms include, for example, bacteria belonging to the genus Geobacter, bacteria belonging to the genus Shewanella, bacteria belonging to the genus Aeromonas, bacteria belonging to the genus Geothrix, and bacteria belonging to the genus Saccharomyces.

A microorganism may be held on the negative electrode 20 by overlapping and fixing a biofilm containing the microorganism on the negative electrode 20. Biofilm generally refers to a three-dimensional structure including a microbial population and an extracellular polymeric substance (EPS) produced by the microbial population. However, the microorganism may be held by the negative electrode 20 without using the biofilm. The microorganism may be held not only on the surface of the negative electrode 20 but also on the inside.

For example, an electron transfer mediator molecule may be modified in the negative electrode 20. Alternatively, the liquid to be treated 60 in the treatment tank 70 may contain an electron transfer mediator molecule. Thereby, the electron transfer from the microorganism to the negative electrode 20 can be promoted, and more efficient liquid processing can be realized.

Specifically, in the mechanism of metabolism by microorganisms, electrons are exchanged within cells or with the final electron acceptor. When a mediator molecule is introduced into the liquid 60 to be treated, the mediator molecule acts as a final electron acceptor for metabolism and transfers the received electron to the negative electrode 20. As a result, it is possible to increase the rate of oxidative decomposition of the organic substance or the like in the liquid 60 to be treated. Such electron transfer mediator molecules are not particularly limited. As the electron transfer mediator molecule, for example, at least one selected from the group consisting of neutral red, anthraquinone-2,6-disulfonic acid (AQDS), thionine, potassium ferricyanide, and methyl viologen can be used.

(Ion transfer layer)
The electrode unit 1 of the present embodiment further includes an ion transfer layer 30 provided between the positive electrode 10 and the negative electrode 20 and having proton permeability. Then, as shown in FIGS. 1 and 2, the negative electrode 20 is separated from the positive electrode 10 via the ion transfer layer 30. The ion transfer layer 30 has a function of transmitting hydrogen ions generated at the negative electrode 20 and moving the hydrogen ions to the positive electrode 10 side.

As the ion transfer layer 30, for example, an ion exchange membrane using an ion exchange resin can be used. As the ion exchange resin, for example, NAFION (registered trademark) manufactured by DuPont Co., Ltd., and Flemion (registered trademark) and Seremion (registered trademark) manufactured by Asahi Glass Co., Ltd. can be used.

Alternatively, as the ion transfer layer 30, a porous membrane having pores through which hydrogen ions can pass may be used. That is, the ion transfer layer 30 may be a sheet having a space (air gap) for hydrogen ions to move from the negative electrode 20 to the positive electrode 10. Therefore, it is preferable that the ion transfer layer 30 includes at least one selected from the group consisting of a porous sheet, a woven sheet and a non-woven sheet. Further, the ion transfer layer 30 may be at least one selected from the group consisting of a glass fiber membrane, a synthetic fiber membrane, and a plastic non-woven fabric, and may be a laminate obtained by laminating a plurality of these. Such a porous sheet has a large number of pores inside, so that hydrogen ions can be easily moved. The pore diameter of the ion transfer layer 30 is not particularly limited as long as hydrogen ions can move from the negative electrode 20 to the positive electrode 10.

As described above, the ion transfer layer 30 has a function of transmitting hydrogen ions generated at the negative electrode 20 and moving the hydrogen ions to the positive electrode 10 side. Therefore, for example, hydrogen ions can move from the negative electrode 20 to the positive electrode 10 if the negative electrode 20 and the positive electrode 10 are close to each other without being in contact with each other. Therefore, in the liquid treatment system 100, the ion transfer layer 30 is not an essential component. However, by providing the ion transfer layer 30, it is possible to efficiently transfer hydrogen ions from the negative electrode 20 to the positive electrode 10. Therefore, it is preferable to provide the ion transfer layer 30 from the viewpoint of output improvement. A space may be provided between the positive electrode 10 and the ion transfer layer 30, and a space may be provided between the negative electrode 20 and the ion transfer layer 30.

In the electrode unit 1, as shown in FIG. 2, the external circuit 80 electrically connected to the negative electrode 20 and the positive electrode 10 is provided. However, in the electrode unit 1, the negative electrode 20 and the positive electrode 10 may be electrically connected directly by using a conductive member without using the external circuit 80. In the electrode unit 1, the entire upper portion of the cassette base 50 is open, but may be partially open if air (oxygen) can be introduced into the inside, or the cassette base 50 is closed. It may be

[Treatment tank]
The liquid processing system 100 includes a substantially rectangular processing tank 70 that holds the liquid to be processed 60 containing an organic substance therein. The treatment tank 70 is provided with an inlet 71 for supplying the liquid to be treated 60 to the treatment tank 70, and an outlet 72 for discharging the liquid to be treated 60 after treatment from the treatment tank 70. In the present embodiment, the inlet 71 is provided at the lower part of the front wall 73 of the processing tank 70, and the outlet 72 is provided at the upper part of the rear wall 74 of the processing tank 70.

The liquid to be treated 60 is continuously supplied to the inside of the treatment tank 70 through the inlet 71. Further, as shown in FIGS. 1 and 2, the electrode unit 1 is disposed inside the treatment tank 70 so as to be immersed in the liquid 60 to be treated. Therefore, the liquid to be treated 60 supplied from the inlet 71 of the treatment tank 70 flows in contact with the electrode unit 1 and then is discharged from the outlet 72.

In the liquid treatment system 100, the electrode units 1 are preferably arranged along the direction from the inflow port 71 to the outflow port 72 in plan view. Specifically, as shown in FIGS. 1 and 3, in the liquid processing system 100, the inlet 71 is provided on the front wall 73 of the processing tank 70, and the outlet 72 is provided on the rear wall 74 opposite to the front wall 73. It is done. Then, the electrode unit 1 is disposed inside the processing tank 70 so that the film-like negative electrode 20 in the electrode unit 1 is substantially parallel to the direction (X direction) from the inflow port 71 toward the outflow port 72. Is preferred. Thereby, as described later, even when the plurality of electrode units 1 are disposed inside the liquid processing system, the concentration of the organic substance in the liquid to be treated 60 in contact with each electrode unit 1 is made comparable. can do. As a result, it is possible to make the amount of power generation of each electrode unit 1 uniform.

[3D structure]
The liquid processing system 100 includes a three-dimensional structure 90 provided between the electrode unit 1 and the processing tank 70. Specifically, as shown in FIGS. 2 and 3, a three-dimensional structure 90 is provided so as to fill the gap between the negative electrode 20 of the electrode unit 1 and the left wall 75 and the right wall 76 of the processing tank 70. . The three-dimensional structure 90 has a substantially rectangular parallelepiped shape, and is disposed to be in contact with the negative electrode 20 and the left wall 75 and the right wall 76. Then, as shown in FIG. 2, the three-dimensional structure 90 is immersed in the liquid 60 to be treated.

As in the case of Patent Document 1, when the liquid to be treated simply flows between the electrode units, the liquid to be treated is in a laminar flow state, so a part of the liquid to be treated does not contact the electrode unit, and the outlet May be discharged from In that case, since the organic substance in the liquid to be treated is difficult to be decomposed by the microorganism, the power generation by the microorganism and the purification of the liquid to be treated can not be efficiently performed.

On the other hand, in the liquid processing system 100 according to the present embodiment, as shown in FIG. 1, a three-dimensional structure 90 is disposed between the electrode unit 1 and the processing tank 70. By providing the three-dimensional structure 90, the liquid to be treated 60 is in a turbulent state, and the diffusivity of the liquid to be treated 60 is enhanced. Therefore, the liquid to be treated 60 easily contacts the negative electrode 20 of the electrode unit 1, and the organic substance in the liquid to be treated 60 can be efficiently decomposed by the microorganisms supported on the negative electrode 20.

In the liquid treatment system 100, the liquid to be treated 60 flows while being in contact with the three-dimensional structure 90. Therefore, the three-dimensional structure 90 may be disposed so as to be filled in the entire flow path of the liquid to be treated 60, or may be disposed only in a part of the flow path of the liquid to be treated 60.

Specifically, when the three-dimensional structure 90 is provided between the electrode unit 1 and the processing tank 70, as shown in FIGS. 2 and 3, the negative electrode 20 of the electrode unit 1 and the left wall 75 of the processing tank 70. Preferably, the three-dimensional structure 90 is disposed in the entire space between them. Similarly, it is preferable to dispose the three-dimensional structure 90 entirely between the negative electrode 20 of the electrode unit 1 and the right wall 76 of the processing tank 70. However, the present embodiment is not limited to such an aspect, and a three-dimensional structure 90 is disposed in a portion between the negative electrode 20 of the electrode unit 1 and the left wall 75 and the right wall 76 of the processing tank 70. It is also good.

In the liquid processing system 100, the upper end 91 of the three-dimensional structure 90 is preferably arranged to be higher than the water surface of the liquid 60 to be treated. Specifically, as shown in FIG. 2, inside the processing tank 70 so that the upper end 91 of the three-dimensional structure 90 is higher than the water surface 61 of the liquid 60 to be treated and the upper end 91 is exposed from the liquid 60 to be treated. It is preferred to be arranged. As a result, the liquid to be treated 60 tends to be in a turbulent state, and the contact between the liquid to be treated 60 and the negative electrode 20 can be further enhanced. However, the present embodiment is not limited to such an aspect, and the upper end 91 of the three-dimensional structure 90 may be lower than the water surface 61 of the liquid 60 to be treated.

In FIG. 2, the lower end 92 of the three-dimensional structure 90 is in contact with the bottom wall 77 of the processing tank 70. As a result, the liquid to be treated 60 tends to be in a turbulent state, and the contact between the liquid to be treated 60 and the negative electrode 20 can be further enhanced. However, the present embodiment is not limited to such an aspect, and a gap may exist between the lower end 92 of the three-dimensional structure 90 and the bottom wall 77 of the processing tank 70.

As described above, the three-dimensional structure 90 makes the liquid to be treated 60 in a turbulent state, and enhances the contact between the liquid to be treated 60 and the negative electrode 20. Therefore, as shown in FIG. 3, the three-dimensional structure 90 is preferably disposed upstream of the rear end 1 a of the electrode unit 1 in the flow direction (X direction) of the liquid 60 to be treated. That is, the rear end 93 of the three-dimensional structure 90 is preferably positioned upstream of the rear end 1 a of the electrode unit 1.

As shown in FIG. 3, the three-dimensional structure 90 is preferably located downstream of the front end 1 b of the electrode unit 1 in the flow direction of the liquid to be treated 60. That is, the front end 94 of the three-dimensional structure 90 is preferably located downstream of the front end 1 b of the electrode unit 1. However, the front end 94 of the three-dimensional structure 90 may be located upstream of the front end 1 b of the electrode unit 1 without being limited to such an embodiment.

In order to make the to-be-treated liquid 60 into a turbulent state and to enhance the contact between the to-be-treated liquid 60 and the negative electrode 20, the three-dimensional structure 90 is upstream of the center 1 c of the electrode unit 1 in the flow direction of the to-be-treated liquid 60. It should just be located at the side. Specifically, as shown in FIG. 5, the rear end 93 of the three-dimensional structure 90 may be located upstream of the center 1 c in the flow direction of the liquid to be treated 60 in the electrode unit 1. As a result, the liquid to be treated 60 comes into contact with the three-dimensional structure 90 to be in a turbulent state, so that the liquid to be treated 60 and the negative electrode 20 can be efficiently brought into contact with each other.

In the present embodiment, the shape of the three-dimensional structure 90 is not particularly limited. However, it is preferable that the three-dimensional structure 90 be provided with a porous body having a plurality of holes through which the liquid to be treated 60 can pass. Further, the three-dimensional structure 90 is more preferably made of the porous body. When the liquid to be treated 60 passes through the inside of such a three-dimensional structure 90, the liquid to be treated 60 changes from a laminar flow state to a turbulent state, so that the contact between the liquid to be treated 60 and the negative electrode 20 is improved. Is possible. The size of the pores of the porous body is not particularly limited, but can be, for example, 1 mm to 50 cm.

The three-dimensional structure 90 preferably comprises a fibrous body, and more preferably comprises a fibrous body. That is, it is preferable that the three-dimensional structure 90 be provided with a fibrous body in which fibers are aggregated. Since such a fibrous body also has a plurality of holes through which the liquid to be treated 60 can pass, the liquid to be treated 60 can be put in a turbulent state. In addition, the fiber which comprises a fibrous body is not specifically limited, At least one of the inorganic fiber which consists of inorganic materials, and the organic fiber which consists of organic materials can be used.

The three-dimensional structure 90 preferably comprises a reticulated body, and more preferably consists of a reticulated body. That is, the porous body having a plurality of the above-mentioned holes is preferably a net-like body. Such a reticulated body also has a plurality of holes through which the liquid to be treated 60 can pass, so the liquid to be treated 60 can be put in a turbulent state. The mesh-like body is preferably a porous structure formed by braiding at least one of a metal wire and a nonmetal wire. The nonmetal wire is not particularly limited, and at least one of an inorganic fiber made of an inorganic material and an organic fiber made of an organic material can be used.

As such a three-dimensional structure 90, for example, a water permeable mat typified by an underdrainage material can be used. As the water-permeable mat, for example, Hetimaron (registered trademark) manufactured by Shinko Nylon Co., Ltd. and a muddy drain mat manufactured by Yoshihara Kako Co., Ltd. can be used.

The material which comprises the three-dimensional structure 90 is not specifically limited, For example, at least one chosen from the group which consists of resin, a metal, a carbon material, and ceramics can be used. As resin which comprises the three-dimensional structure 90, at least one chosen from the group which consists of a thermosetting resin, a thermoplastic resin, and an elastomer can be used, for example, polyolefin resin can be used. As a metal which comprises the three-dimensional structure 90, at least one chosen from the group which consists of aluminum, copper, stainless steel, nickel, and titanium can be used. As the carbon material constituting the three-dimensional structure 90, at least one selected from the group consisting of carbon paper, carbon felt, carbon fiber and graphite sheet can be used.

In the present embodiment, the three-dimensional structure 90 preferably has conductivity. When the three-dimensional structure 90 has conductivity, in addition to the negative electrode 20 of the electrode unit 1, it becomes possible to support a microorganism on the three-dimensional structure 90. That is, as described above, the negative electrode 20 of the electrode unit 1 generates hydrogen ions and electrons from the organic substance of the liquid to be treated 60 by the catalytic action of the microorganism. The generated electrons move to the positive electrode 10 through the negative electrode 20 and the external circuit 80. Therefore, when the three-dimensional structure 90 has conductivity, an electron generated by the microorganism can be moved to the positive electrode 10 through the three-dimensional structure 90 and the external circuit 80 by supporting the microorganism on the three-dimensional structure 90. . As a result, power generation by the liquid processing system 100 can be performed more efficiently.

Next, the operation of the liquid treatment system 100 of the present embodiment will be described. When the electrode assembly 40 including the positive electrode 10, the negative electrode 20, and the ion transfer layer 30 is immersed in the liquid 60, the gas diffusion layer 12, the negative electrode 20, and the ion transfer layer 30 of the positive electrode 10 are immersed in the liquid 60, At least a part of the water repellent layer 11 is exposed to the gas phase 2.

At the time of operation of the liquid treatment system 100, the liquid to be treated 60 containing at least one of an organic substance and a nitrogen-containing compound is supplied to the negative electrode 20 and air is supplied to the positive electrode 10. At this time, air is continuously supplied through the opening provided at the top of the cassette base 50.

Then, in the positive electrode 10, oxygen permeates the water repellent layer 11 and diffuses into the gas diffusion layer 12. In the negative electrode 20, hydrogen ions and electrons are generated from at least one of the organic substance and the nitrogen-containing compound in the liquid to be treated 60 by the catalytic action of microorganisms. The generated hydrogen ions permeate the ion transfer layer 30, move to the positive electrode 10 side, and reach the gas diffusion layer 12 in the positive electrode 10. The generated electrons move to the external circuit 80 through the conductor sheet of the negative electrode 20, and further move to the gas diffusion layer 12 of the positive electrode 10 from the external circuit 80. The hydrogen ions and electrons are combined with oxygen by the action of the catalyst in the gas diffusion layer 12 and consumed as water. At this time, the external circuit 80 recovers the electrical energy flowing to the closed circuit. Thus, the electrode unit 1 can degrade at least one of the organic substance and the nitrogen-containing compound in the liquid to be treated 60 by the action of the microorganism in the negative electrode 20.

Here, in the liquid treatment system 100, the liquid to be treated 60 is continuously supplied from the inlet 71 of the treatment tank 70. The supplied liquid to be treated 60 comes in contact with the three-dimensional structure 90 and diffuses in a turbulent state, and thus is efficiently supplied to the negative electrode 20. Then, the organic substance in the liquid 60 to be treated is decomposed by the microorganisms carried on the negative electrode 20. As described above, since the liquid to be treated 60 is efficiently supplied to the negative electrode 20 and the organic substance is decomposed by microorganisms, stable power generation characteristics can be obtained from the electrode unit 1.

The liquid processing system of the present embodiment may be configured to include one electrode unit 1 inside one processing tank 70 as shown in FIGS. 1 to 3. However, the present embodiment is not limited to such a configuration. For example, a plurality of electrode units 1 may be provided in one processing tank 70. Specifically, as shown in FIGS. 6 to 8, five electrode units 1 may be provided inside one processing tank 70. With such a configuration, the contact between the liquid 60 to be treated and the negative electrode 20 of the electrode unit 1 can be enhanced, and power generation by microorganisms and purification of wastewater can be performed more efficiently.

In the liquid processing system 100A shown in FIGS. 6-8, the inlet 71 is provided on the front wall 73 of the processing tank 70, and the outlet 72 is a rear wall facing the front wall 73, as in the liquid processing system 100 described above. Provided in 74. The five electrode units 1 are disposed inside the processing tank 70 such that the negative electrode 20 is substantially parallel to the direction (X direction) from the inflow port 71 toward the outflow port 72.

The three-dimensional structure 90 is provided between the adjacent electrode units 1 in addition to the space between the electrode unit 1 and the processing tank 70. By providing the three-dimensional structure 90 between the adjacent electrode units 1, the liquid to be treated 60 contacts and diffuses the three-dimensional structure 90, and the contact between the liquid to be treated 60 and the negative electrode 20 can be enhanced. .

In addition, when providing the three-dimensional structure 90 between the adjacent electrode units 1, as shown in FIG. 6, the whole between the negative electrode 20 of one electrode unit 1 and the negative electrode 20 of the other electrode unit 1 It is preferable to arrange the three-dimensional structure 90 in FIG. However, the present embodiment is not limited to such an aspect, and the three-dimensional structure 90 may be disposed in a part between the negative electrode 20 of one electrode unit 1 and the negative electrode 20 of the other electrode unit 1 .

In the liquid processing system 100A shown in FIGS. 6 to 8, in addition to the space between the electrode unit 1 and the processing tank 70, a three-dimensional structure 90 is provided also between the adjacent electrode units 1. However, the present embodiment is not limited to such an aspect, and the three-dimensional structure 90 is not provided between the electrode unit 1 and the processing tank 70, and the three-dimensional structure 90 is provided only between the adjacent electrode units 1. May be

Thus, the

liquid processing system

100, 100A of the present embodiment holds the liquid to be treated 60 containing an organic substance, and includes the treatment tank 70 having the inlet 71 and the outlet 72 of the liquid to be treated 60. The liquid processing system further includes one or more electrode units 1 provided inside the processing tank 70 and arranged in a direction (X direction) from the inlet 71 toward the outlet 72 in plan view. Prepare. Further, the liquid processing system includes a three-dimensional structure 90 provided in at least one of between the electrode unit 1 and the processing tank 70 and between the adjacent electrode units 1. Then, the electrode unit 1 includes the negative electrode 20 supporting the microorganism and the positive electrode 10 electrically connected to the negative electrode 20, and the negative electrode 20 and the positive electrode 10 are immersed in the liquid 60 to be treated. Is exposed to the gas phase 2.

In the

liquid processing system

100, 100A of the present embodiment, a three-dimensional structure 90 is provided at least between the electrode unit 1 and the processing tank 70 and between the adjacent electrode units 1. Then, the liquid to be treated 60 passes through the inside of the three-dimensional structure 90 and contacts the negative electrode 20, and then flows to the outlet 72. Thereby, the liquid to be treated 60 can be diffused, and the contact between the negative electrode 20 of the electrode unit 1 and the liquid to be treated 60 can be enhanced. As a result, the microorganisms carried on the negative electrode 20 can efficiently perform power generation and purification of the liquid 60 to be treated. Further, in the liquid processing system 100, the plurality of electrode units 1 are arranged along the direction from the inflow port 71 toward the outflow port 72, whereby the organic substance in the liquid to be treated 60 in contact with each electrode unit 1 The concentration of As a result, it is possible to make the amount of power generation of each electrode unit 1 uniform.

Hereinafter, the present embodiment will be described in more detail by way of examples and comparative examples, but the present embodiment is not limited to these examples.

[Example]
First, a silicone resin which is an adhesive agent is applied to a water repellent layer made of polyolefin and then a graphite foil which is a gas diffusion layer is joined to produce a laminated sheet consisting of water repellent layer / silicone adhesive / gas diffusion layer did. As the water repellent layer, Cellpore (registered trademark) manufactured by Sekisui Chemical Co., Ltd. was used. As the silicone resin, one-component RTV rubber KE-3475-T manufactured by Shin-Etsu Chemical Co., Ltd. was used. The graphite foil used was manufactured by Hitachi Chemical Co., Ltd.

Next, a gas diffusion electrode was produced by press-forming a catalyst layer formed by mixing an oxygen reduction catalyst and PTFE (manufactured by Aldrich) on the surface of the graphite foil opposite to the water repellent layer. In addition, the oxygen reduction catalyst was press-molded so that a basis weight might be 6 mg / cm < ² >.

The oxygen reduction catalyst was prepared as follows. First, a mixed solution was prepared by placing 3 g of carbon black, a 0.1 M aqueous solution of iron (III) chloride, and an ethanol solution of 0.15 M pentaethylenehexamine in a container. As carbon black, ketjen black ECP600 JD manufactured by Lion Specialty Chemicals Co., Ltd. was used. The amount of use of the 0.1 M aqueous solution of iron (III) chloride was adjusted so that the ratio of iron atoms to carbon black was 10% by mass. The total volume was adjusted to 9 mL by further adding ethanol to this mixture. Then, the mixture was ultrasonically dispersed and then dried at a temperature of 60 ° C. in a drier. This yielded a sample containing carbon black, iron (III) chloride, and pentaethylenehexamine.

The sample was then packed into one end of a quartz tube, which was subsequently purged with argon. The quartz tube was put into a furnace at 900 ° C. and pulled out in 45 seconds. When inserting the quartz tube into the furnace, the temperature rising rate of the sample at the start of heating was adjusted to 300 ° C./s by inserting the quartz tube into the furnace over 3 seconds. Subsequently, the sample was cooled by flowing argon gas through the quartz tube. Thus, an oxygen reduction catalyst was obtained.

A positive electrode was manufactured by providing an air intake portion in the water repellent layer of the gas diffusion electrode obtained as described above. And as shown in FIG. 1, the negative electrode which consists of a positive electrode and a carbon material (graphite foil) was installed in the processing tank provided with the inlet and the outlet. Furthermore, a non-woven fabric made of polyolefin, which is an ion transfer layer, was placed between the positive electrode and the negative electrode. The treatment tank used had a capacity of 300 cc.

Furthermore, in this example, as shown in FIG. 2 and FIG. 3, urethane foam, which is a three-dimensional structure, was filled between the negative electrode and the right and left walls of the treatment tank. As the urethane foam, a soft urethane foam U0016 manufactured by Fuji Rubber Industries Ltd. was used. Therefore, after the liquid to be treated enters the treatment tank through the inlet, it flows through the inside of the urethane foam and is discharged from the outlet.

Next, the treatment liquid was filled in the treatment tank so as to be in contact with the positive electrode, the negative electrode, the ion transfer layer, and the urethane foam. As a liquid to be treated, a model waste liquid having a total organic carbon (TOC) of 500 mg / L was used. Furthermore, in order to stabilize the proton supply property of the liquid to be treated, sodium hydrogen carbonate was added as a buffer to a concentration of 5 mM. Furthermore, soil microorganisms were planted on the negative electrode as a source of anaerobic microorganisms that generate electricity.

Then, the liquid to be treated was supplied to the treatment tank so that the hydraulic retention time was 12 hours. Furthermore, the liquid to be treated was adjusted to have a water temperature of 30 ° C. And the liquid processing system of this example was obtained by connecting a positive electrode and a negative electrode to a load circuit.

[Comparative example]
The liquid treatment system of this example was obtained in the same manner as the example except that the three-dimensional structure was not installed.

[Evaluation]
The liquid treatment systems of Examples and Comparative Examples were operated for 80 days, and the steady-state output of the liquid treatment system was measured. In FIG. 9, the relationship of the working days and steady-state output in the liquid processing system of an Example and a comparative example was shown.

As shown in FIG. 9, in the liquid processing system of the example, the output remains around 200 mW / m ² even after 80 days have passed since startup, and it can be seen that good output characteristics can be obtained. On the other hand, it can be seen that in the liquid processing system of the comparative example, the output decreases after 50 days from the start-up. Therefore, it is understood that the liquid to be treated is diffused by providing the three-dimensional structure, and the organic substance is efficiently decomposed by the microorganism, so that stable power generation can be performed.

As mentioned above, although this embodiment was described, this embodiment is not limited to these, A various deformation | transformation is possible within the range of the summary of this embodiment. Specifically, in the drawings, the positive electrode 10, the negative electrode 20, and the ion transfer layer 30 are formed in a rectangular shape. However, these shapes are not particularly limited, and can be arbitrarily changed according to the size of the liquid treatment system, the desired purification performance, and the like. Also, the area of each layer can be arbitrarily changed as long as the desired function can be exhibited.

The liquid treatment system according to the present embodiment can be widely applied to the treatment of a liquid containing an organic substance, for example, wastewater generated from factories of various industries, and organic wastewater such as sewage. It can also be used to improve the environment of water areas.

The entire contents of Japanese Patent Application No. 2017-202061 (filing date: October 18, 2017) are incorporated herein by reference.

According to the present disclosure, it is possible to provide a liquid treatment system capable of enhancing the contact between the electrode unit and the wastewater and efficiently performing the power generation by microorganisms and the purification of the wastewater.

Reference Signs List 1 electrode unit 2 gas phase 10 positive electrode 20 negative electrode 60 treated liquid 70 treatment tank 71 inlet 72 outlet 90 three-

dimensional structure

100, 100 A liquid processing system

Claims

A processing tank holding a liquid containing an organic substance, and having an inlet and an outlet for the liquid;
One or more electrode units provided inside the processing tank and arranged in a direction from the inlet to the outlet in plan view;
A three-dimensional structure provided at least one of between the electrode unit and the processing tank and between the adjacent electrode units;
Equipped with
The electrode unit includes a negative electrode supporting a microorganism, and a positive electrode electrically connected to the negative electrode, the negative electrode and the positive electrode are immersed in the liquid to be treated, and at least a portion of the positive electrode is in a gas phase. Exposed, liquid handling system.
The liquid treatment system according to claim 1, wherein the three-dimensional structure includes a porous body having a plurality of holes through which the liquid to be treated can pass.
The liquid treatment system according to claim 2, wherein the porous body is a mesh.
The liquid treatment system according to any one of claims 1 to 3, wherein the three-dimensional structure has conductivity.
The liquid processing system according to any one of claims 1 to 4, wherein the liquid to be treated flows into the outlet after passing through the inside of the three-dimensional structure and contacting with the negative electrode.