JP5407156B2 - Microbial power generation method and microbial power generation apparatus - Google Patents

Description

  The present invention relates to a power generation method and apparatus using a metabolic reaction of microorganisms. In particular, the present invention relates to a microbial power generation method and apparatus for taking out the reducing power obtained when an organic substance is oxidatively decomposed into microorganisms as electric energy.

  In recent years, the need for a power generation method in consideration of the global environment has increased, and technological development of microbial power generation has been promoted. Microbial power generation is a method of generating electricity by taking out electrical energy obtained when microorganisms assimilate organic matter.

  In general, in microbial power generation, microorganisms, organic substances assimilated by microorganisms, and electron transfer media (electron mediators) coexist in a negative electrode chamber in which a negative electrode is arranged. The electron mediator enters the microorganism, receives the electrons generated by the microorganisms oxidizing the organic matter, and passes them to the negative electrode. The negative electrode is electrically connected to the positive electrode via an external resistance (load), and the electrons transferred to the negative electrode move to the positive electrode via the external resistance (load) and are transferred to the electron acceptor in contact with the positive electrode. A current flows between the positive electrode and the negative electrode due to such movement of electrons.

  In microbial power generation, the electron mediator takes out electrons directly from the microbial body, so the theoretical energy conversion efficiency is high. However, actual energy conversion efficiency is low, and improvement in power generation efficiency is required. Therefore, various studies and developments have been made on electrode materials and structures, types of electron mediators, selection of microbial species, and the like in order to increase power generation efficiency (for example, Patent Documents 1 and 2).

  In Patent Document 1, the positive electrode chamber and the negative electrode chamber are separated by an alkali ion conductor made of a solid electrolyte, the positive electrode chamber and the negative electrode chamber are set to pH 7 with a phosphate buffer (buffer), and air is blown into the positive electrode chamber to generate power. It is described to do.

In Patent Document 2, a porous body is installed as a positive electrode plate so as to be in contact with an electrolyte membrane that partitions a positive electrode chamber and a negative electrode chamber, air is circulated through the positive electrode chamber, and air and liquid are admitted in the voids of the porous body. It is described to make contact with.
JP 2000-133326 A Japanese Patent Application Laid-Open No. 2004-342412

  When the microbial power generation apparatus is operated, carbon dioxide gas is generated in the negative electrode chamber along with the microbial reaction, and the pH is lowered. In patent document 1, the pH change accompanying reaction in a negative electrode chamber is suppressed by adding a high concentration phosphate buffer to the liquid supplied to a negative electrode chamber. However, as a result of studies by the present inventors, it has been found that when the power generation efficiency is increased, the pH in the negative electrode chamber is significantly lowered, and the power generation efficiency is decreased. For this reason, when it is going to obtain high power generation efficiency, if there is little addition amount of a buffer, pH change cannot be suppressed and it will cause power generation efficiency fall. On the other hand, if an attempt is made to suppress a change in pH with a buffer, a large amount of buffer needs to be added, resulting in high costs and impracticality.

  The present invention provides a microbial power generation method and apparatus capable of increasing the efficiency of microbial power generation by maintaining the pH in the negative electrode chamber at 7 to 9 without using a phosphate buffer or reducing the amount of use thereof. The purpose is to provide.

The microbial power generation method of the present invention (Claim 1) has a negative electrode, holds a microorganism, and holds a negative electrode solution containing an electron donor, and is separated from the negative electrode chamber via a cation exchange membrane. In the microbial power generation method for generating electricity by supplying an oxygen-containing gas to the positive electrode chamber of a microbial power generation apparatus including a positive electrode chamber having a positive electrode in contact with the cation exchange membrane, the negative electrode is made of graphite, titanium or stainless steel. The negative electrode is in contact with the cation exchange membrane, the negative electrode is filled in the entire negative electrode chamber, and the negative electrode solution supplied into the negative electrode chamber is porous. is configured to transmit the negative electrode made of sheet, removed anode solution in the negative electrode chamber from the circulation往口, circulation pipe and is circulated back to the anode chamber via the circulation pump and a circulation Modokuchi co , By addition of condensed water is taken out from the positive electrode chamber to the negative electrode solution flowing through the circulation pipe, and is characterized in adjusting the pH of the negative electrode chamber 7-9.

The microorganism power generation device of the present invention (Claim 2 ) has a negative electrode, holds a microorganism, and holds a negative electrode solution containing an electron donor, and is separated from the negative electrode chamber via a cation exchange membrane. and which, in a microorganism generating device including a positive electrode chamber having a cathode in contact with the cation exchange membrane, means for supplying an oxygen-containing gas into the positive electrode chamber, and circulation provided negative electrode chamber 往口and circulation A return pipe, a circulation pipe connecting the circulation outlet and the circulation return opening so as to circulate the negative electrode solution, a circulation pump provided in the circulation pipe, and condensed water taken out from the positive electrode chamber by adding to the negative electrode solution flowing, and a pH adjusting means for adjusting the pH of the negative electrode chamber 7-9, the negative electrode graphite, made of porous sheets of electrically conductive made of titanium or stainless steel, The negative electrode It is in contact with the cation exchange membrane, the negative electrode is filled in the entire negative electrode chamber, and the negative electrode solution supplied into the negative electrode chamber is configured to pass through the negative electrode made of the porous sheet. It is characterized by.

  The present invention pays attention to the fact that the condensed water taken out from the positive electrode chamber is alkaline, and supplies the positive electrode chamber condensed water to the negative electrode chamber to adjust the pH of the negative electrode chamber to 7 to 9, thereby The power generation efficiency is kept high. According to the present invention, the pH of the negative electrode chamber can be maintained at 7 to 9 without using a phosphate buffer or reducing the amount of addition thereof.

  Hereinafter, the present invention will be described in more detail.

  FIG. 2 is a schematic cross-sectional view showing a schematic configuration of the microbial power generation method and apparatus of the present invention.

  The tank body 1 is partitioned into a positive electrode chamber 3 and a negative electrode chamber 4 by a cation permeator 2. In the positive electrode chamber 3, a positive electrode 5 made of a conductive porous material is disposed so as to be in contact with the cation permeant 2.

A negative electrode 6 made of a conductive porous material is disposed in the negative electrode chamber 4. The negative electrode 6 is in contact with the cation permeant 2 directly or through a membrane of about 1 to 2 layers of microorganisms, and protons (H ⁺ ) can be transferred from the negative electrode 6 to the cation permeant 2. .

  The inside of the positive electrode chamber 3 is an empty chamber, oxygen-containing gas such as air is introduced from the gas inlet 7, and exhaust gas flows out from the gas outlet 8. A negative electrode solution L exists in the negative electrode chamber 4, and this negative electrode solution L is circulated through a circulation outlet 9, a circulation pipe 10, a circulation pump 11 and a circulation return port 12.

  As the cation permeator 2, a cation exchange membrane is suitable as described later, but other materials may be used.

  Microorganisms are supported on the negative electrode 6 made of a porous material. A negative electrode solution L is introduced into the negative electrode chamber 4 from the inlet 4a, and the waste liquid is discharged from the outlet. The inside of the negative electrode chamber 4 is anaerobic.

  The condensed water generated in the positive electrode chamber 3 can be introduced into the circulation pipe 10 through the condensed water outlet 13, the condensed water pipe 14, the condensed water tank 15, the pipe 16, and the valve 17. Since the pipe 16 is connected to the suction side of the pump 11, the condensed water in the tank 15 is sucked into the pipe 16 when the valve 17 is opened. However, a pump may be provided in the pipe 16 instead of the valve 17. The tank 15 also has an action of settling and separating insoluble substances.

  Due to the electromotive force generated between the positive electrode 5 and the negative electrode 6, a current flows through the external resistor 21 via the terminals 20 and 22.

  The condensed water in the positive electrode chamber 3 is added to the negative electrode solution L so that the pH of the negative electrode solution L is 7-9. This positive electrode chamber condensed water may be added directly to the negative electrode chamber 6, but by adding to the circulating water, the entire area in the negative electrode chamber 6 can be maintained at pH 7 to 9 without partial bias. Since the condensed water may contain oxygen, the condensed water may be deoxygenated by a deoxygenating device such as an activated carbon packed tower and then added to the negative electrode solution.

By ventilating the oxygen-containing gas into the positive electrode chamber 3 and operating the pump 11 as necessary to circulate the negative electrode solution L,
(Organic) + H ₂ O → CO ₂ + H ⁺ + e ⁻
The reaction proceeds. The electrons e ⁻ flow to the positive electrode 5 through the negative electrode 6, the terminal 22, the external resistor 21, and the terminal 20.

Proton H ⁺ generated by the above reaction moves to the positive electrode 5 through the cation permeant 2. In the positive electrode 5,
O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O
The reaction proceeds. This water H ₂ O is condensed to produce condensed water. In this condensed water, K ^<+> , Na ^<+> etc. which permeate | transmitted the cation permeation | transmission body 2 melt | dissolve, and, thereby, condensed water becomes high alkalinity about pH 9.5-12.5.

In the negative electrode chamber 4, the pH tends to decrease due to the generation of CO ₂ by the decomposition reaction of water by microorganisms. As described above, by adding highly alkaline condensed water from the positive electrode chamber 5 to the negative electrode solution L, the pH of the negative electrode solution L is prevented from becoming lower than 7.

  FIG. 1 is a schematic cross-sectional view of a microbial power generation apparatus according to a particularly preferred embodiment of the present invention.

  Two plate-like cation permeators 31, 31 are arranged in parallel with each other in a substantially rectangular parallelepiped tank 30, thereby forming a negative electrode chamber 32 between the cation permeators 31, 31. Two positive electrode chambers 33 and 33 are formed with the negative electrode chamber 32 and the cation permeator 31 therebetween.

A negative electrode 34 made of a porous material is disposed in the negative electrode chamber 32 so as to be in contact with each cation permeator 31 directly or through a biofilm of about one to two layers. The negative electrode 34 is preferably pressed lightly (for example, at a pressure of 0.1 kg / cm ² or less) against the cation permeant.

  A positive electrode 35 made of a porous material is disposed in the positive electrode chamber 33 in contact with the cation permeator 31. This positive electrode 35 is pressed against the cation permeator 31 by being pressed by the packing 36. In order to improve the adhesion between the positive electrode 35 and the cation permeable material, both may be welded or bonded with an adhesive.

  Between the positive electrode 35 and the side wall of the tank body 30 is a circulation space for oxygen-containing gas.

  The positive electrode 35 and the negative electrode 34 are connected to an external resistor 38 via terminals 37 and 39.

  The negative electrode solution 32 is introduced into the negative electrode chamber 32 from the inlet 32a, and the waste liquid flows out from the outlet 32b. The inside of the negative electrode chamber 32 is anaerobic.

  The negative electrode solution in the negative electrode chamber 32 is circulated through the circulation outlet 41, the circulation pipe 42, the circulation pump 43 and the circulation return port 44. The oxygen-containing gas flows into each positive electrode chamber 33 from the gas inlet 51 and the exhaust gas flows out from the gas outlet 52.

  The condensed water in the positive electrode chamber 33 is introduced into the condensed water tank 55 through the condensed water outlet 53 and the pipe 54 and stored. The condensed water in the condensed water tank 55 can be supplied to the negative electrode chamber 32 via a pipe 56, a valve 57, a circulation pipe 42, and a pump 43.

  Since the pipe 56 is connected to the suction side of the pump 43, the condensed water in the tank 55 is sucked into the pipe 50 when the valve 57 is opened. A pump may be provided in the pipe 56 instead of the valve 57.

  The pH of the negative electrode solution is detected by a pH meter 60, and the valve 57 is controlled by a controller (not shown) so that the pH becomes 7-9.

  Also in the microbial power generation apparatus of FIG. 1, the oxygen-containing gas is circulated through the positive electrode chamber 33, the negative electrode solution is circulated through the negative electrode chamber 32, and preferably the negative electrode solution is circulated, so A potential difference is generated in the current, and a current flows through the external resistor 38.

  With this power generation operation, high pH condensed water is generated in the positive electrode chamber 33 and stored in the tank 55. By adding high pH condensed water generated in the positive electrode chamber 33 from the tank 55 to the negative electrode chamber 32 whose pH is about to be lowered by the microbial reaction, the pH in the negative electrode chamber 32 is maintained at 7-9.

  Next, in addition to microorganisms and negative electrode solutions of this microbial power generation apparatus, suitable materials for the cation permeator, the negative electrode, and the positive electrode will be described.

  Microorganisms that produce electrical energy by being contained in the negative electrode solution L are not particularly limited as long as they have a function as an electron donor. For example, Saccharomyces, Hansenula, Candida, Micrococcus, Staphylococcus, Streptococcus, Leuconostoa, Lactobacillus, Corynebacterium, Arthrobacter, Bacillus, Clostridium, Neisseria, Escherichia, Enterobacter, Serratia, Aigenes Examples include bacteria, filamentous fungi, and yeasts belonging to the genera Gluconobacter, Pseudomonas, Xanthomonas, Vibrio, Comamonas, and Proteus (Proteus vulgaris). As a sludge containing such microorganisms, activated sludge obtained from biological treatment tanks that treat organic matter-containing water such as sewage, microorganisms contained in effluent from the first sedimentation basin of sewage, anaerobic digested sludge, etc. The microorganism can be held in the negative electrode by supplying to the chamber. In order to increase the power generation efficiency, the amount of microorganisms retained in the negative electrode chamber is preferably high, and for example, the microorganism concentration is preferably 1 to 50 g / L.

  As the negative electrode solution L, a solution that holds microorganisms or cells and has a composition necessary for power generation is used. For example, in the case of generating electricity in the respiratory system, the negative side solution includes energy required for respiratory system metabolism such as bouillon medium, M9 medium, L medium, Malt Extract, MY medium, and nitrifying bacteria selection medium. A medium having a composition such as a source and nutrients can be used. In addition, organic waste such as sewage, organic industrial wastewater, and garbage can be used.

  The negative electrode solution L may contain an electron mediator in order to make it easier to extract electrons from microorganisms or cells. Examples of the electron mediator include compounds having a thionin skeleton such as thionine, dimethyldisulfonated thionine, new methylene blue and toluidine blue-O, and 2-hydroxy-1,4-naphthoquinone such as 2-hydroxy-1,4-naphthoquinone. Examples include compounds having a skeleton, brilliant cresyl blue, galocyanine, resorufin, alizarin brilliant blue, phenothiazinone, phenazine esosulphate, safranin-O, dichlorophenolindophenol, ferrocene, benzoquinone, phthalocyanine, or benzyl viologen and their derivatives. be able to.

  Furthermore, if materials that increase the power generation function of microorganisms, such as antioxidants such as vitamin C, or materials that increase the function of only specific electron transfer systems or substance transfer systems in microorganisms, are dissolved, power can be more efficiently generated. Is preferable.

  The negative electrode solution L may contain a phosphate buffer as necessary.

  The negative electrode solution L contains an organic substance. The organic substance is not particularly limited as long as it can be decomposed by microorganisms. For example, water-soluble organic substances, organic fine particles dispersed in water, and the like are used. The negative electrode solution may be organic wastewater such as sewage and food factory effluent. The organic substance concentration in the negative electrode solution L is preferably a high concentration of about 100 to 10000 mg / L in order to increase the power generation efficiency.

  Air is suitable as the oxygen-containing gas to be circulated in the positive electrode chamber. The exhaust gas from the positive electrode chamber may be deoxygenated as necessary, and then vented to the negative electrode chamber to be used for purging dissolved oxygen from the negative electrode solution L.

As the cation permeator, almost any cation permeate can be used as long as it is non-conductive and has cation permeability. Inexpensive materials such as filter paper, woven fabric, and non-woven fabric with good water permeability, microfiltration membrane, ultrafiltration (UF) membrane, reverse osmosis (RO) membrane, and cation permeable membrane with high proton selectivity are preferably used. For example, Nafion (registered trademark) manufactured by DuPont Co., Ltd., a CMB membrane that is a cation exchange membrane manufactured by Astom Co., Ltd., or the like can be used. The cation permeator is preferably thin and strong.
The negative electrode is preferably a porous body having a large surface area and a large number of voids and water permeability so that a large number of microorganisms can be retained. Specific examples include a conductive material sheet having a roughened surface and a porous conductor (for example, graphite felt, expanded titanium, expanded stainless steel, etc.) in which the conductive material is made into a felt-like porous sheet. .

  When such a porous negative electrode is brought into contact with the cation permeant directly or through a microorganism layer, electrons generated by the microbial reaction can pass to the negative electrode without using the electron mediator, and the electron mediator is It can be unnecessary.

  A plurality of sheet-like conductors may be laminated to form a negative electrode. In this case, the same kind of conductor sheets may be laminated, or different kinds of conductor sheets (for example, a graphite sheet having a rough surface and a graphite felt) may be laminated.

  The negative electrode preferably has a total thickness of 3 mm to 40 mm, particularly about 5 to 20 mm. When a negative electrode is constituted by a laminated sheet, it is preferable to orient the laminated surface in a direction connecting the liquid inlet and outlet so that the liquid flows along a mating surface (laminated surface) between the sheets.

  The positive electrode is preferably a catalyst in which a catalyst is supported on a porous substrate made of a conductive material. For example, a catalyst in which platinum is supported on a graphite felt is preferable. If large electric power is not required, an inexpensive graphite electrode may be used as it is (that is, without carrying platinum) as a positive electrode. Moreover, you may use cheap catalysts other than platinum, for example, cobalt, nickel, etc. The graphite felt may be a graphite felt hydrophobized with polytetrafluoroethylene (PTFE).

  In the present invention, the negative electrode chamber may be divided into a plurality of compartments, and the pH of the liquid in the negative electrode compartment may be adjusted after suppressing the pH drop in each compartment by connecting the compartments in series. If the negative electrode chamber is divided, the amount of organic matter decomposition in each of the compartments is reduced, and as a result, the amount of carbon dioxide gas produced is also reduced, so that the pH drop in each of the compartments can be reduced. Cathode condensed water may be added to the liquid flowing in the negative electrode chamber when it flows from the front-stage compartment to the rear-stage compartment. If it does in this way, the pH of the liquid in which the pH has decreased in the front compartment can be raised and flowed into the rear compartment, and the pH of the liquid in the negative compartment can be easily adjusted to the above range.

  In this invention, you may provide the alkali addition means which adds alkalis, such as NaOH aqueous solution, to a negative electrode chamber different from positive electrode chamber condensed water. This alkali may be added to the negative electrode chamber, may be added to the circulation pipe, may be added to the condensed water tank, or may be added to the negative electrode solution introduced into the negative electrode chamber.

  Hereinafter, reference examples and examples will be described.

[Reference Example 1]
A microbial power generation apparatus shown in FIG. 1 was prepared. The entire volume of the tank body 30 of this power generator is 525 mL, the volume of the negative electrode chamber 32 is 175 mL, and the volume of each positive electrode chamber 33 is 175 mL. Each positive electrode chamber 33 was provided with an air supply port at the top and an air outlet at the bottom.

  A cation permeable membrane (trade name (registered trademark) “Nafion” manufactured by DuPont Co., Ltd.) was disposed as the cation permeant 31.

  As the negative electrode 34, graphite felt (manufactured by Toyo Carbon Co., Ltd.) having a size of 250 mm × 70 mm and a thickness of 10 mm was used. Both surfaces of this graphite felt are rough. The negative electrode 34 was filled in the entire negative electrode chamber 32 as shown in the figure, and the negative electrode 34 and the cation permeable membrane 35 were pressed and brought into contact with each other. That is, the liquid supplied to the negative electrode chamber 32 is configured to pass through the porous negative electrode 34, and does not substantially pass through the negative electrode chamber 32 (short path) without passing through the negative electrode 34. Has been. In the negative electrode chamber 32, activated sludge collected from a biological treatment tank of a sewage treatment plant was added and cultured as an inoculum, and microorganisms were attached to the surface of the graphite felt constituting the negative electrode. The microorganism concentration in the negative electrode chamber 32 was about 2200 mg / L.

Each of the positive electrodes 35 was composed of one platinum-supported graphite felt having a thickness of 3 mm. This graphite felt is hydrophobized by applying a xylene dispersion of PTFE fine particles and then heat-treating at 400 ° C. for baking. Further, activated carbon-supported platinum (manufactured by Sigma Aldrich Japan Co., Ltd., containing 10% Pt) is cation-permeable. 0.5 mg / cm ^{2 is} supported on the surface in contact with the film 31 (liquid side).

The spacer 36 was disposed, and the positive electrode 35 was pressed against the cation permeable membrane 31 with a pressure of about 0.1 kg / cm ² to bring them into close contact.

  Air was supplied to the positive electrode chamber 33 at 1000 mL / min. The negative electrode chamber 32 is supplied with a stock solution containing acetic acid at a concentration of 1,000 mg / L, a phosphate buffer at a concentration of 50 mM, and 300 mg / L of ammonium chloride at an inflow rate of 70 mL / min. Was discharged.

  The circulation flow rate of the circulation pipe 42 was 10 mL / min.

  In this reference example, the condensed water in the positive electrode chamber was not added to the circulating liquid, but instead sodium hydroxide having a concentration of 1 N was added to the circulating liquid.

  The amount of sodium hydroxide added to the circulating liquid was changed, and the relationship between the pH of the liquid in the negative electrode chamber 32 and the power generation amount was determined. The results are shown in FIG. In the figure, the power generation efficiency is shown as a power generation amount per unit volume of the anode. As shown in FIG. 3, it has been found that when the pH of the effluent from the negative electrode chamber 32 is less than 7, the power generation efficiency is rapidly reduced. Similarly, when the effluent from the negative electrode chamber 32 exceeded pH 9, the power generation efficiency decreased rapidly.

[Example 1]
From the above reference example, it was shown that the pH of the liquid in the negative electrode chamber 11 affects the power generation efficiency. Therefore, as Example 1, as shown in FIG. 1, the condensed water in the positive electrode chamber 33 was added to the circulating liquid so that the pH of the effluent from the negative electrode chamber 32 was maintained at 7.5. At this time, the circulating liquid circulating and flowing into the negative electrode chamber 32 was set to pH 8.2. Other conditions were the same as in Reference Example 1.

In Example 1, the carbonic acid concentration of the effluent flowing out from the negative electrode chamber 32 was 340 mg / L as inorganic carbonic acid (IC). In addition, an electric power of 120 W / m ³ per unit volume of the negative electrode was obtained.

It is a cross-sectional schematic diagram of the microbial power generation device which concerns on one Embodiment of this invention. It is a cross-sectional schematic diagram of the microbial power generation device which concerns on one Embodiment of this invention. It is a graph which shows a test result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,30 Tank 2,31 Cation | permeation body 3,33 Positive electrode chamber 4,32 Negative electrode chamber 5,35 Positive electrode 6,34 Negative electrode

Claims (2)

A negative electrode chamber having a negative electrode, holding microorganisms, and holding a negative electrode solution containing an electron donor;
Electric power is generated by supplying an oxygen-containing gas to the positive electrode chamber of a microbial power generation apparatus that is separated from the negative electrode chamber via a cation exchange membrane and includes a positive electrode chamber having a positive electrode in contact with the cation exchange membrane. In the microbial power generation method,
The negative electrode is made of a conductive porous sheet made of graphite, titanium, or stainless steel, the negative electrode is in contact with the cation exchange membrane, the negative electrode is filled in the entire negative electrode chamber, and is supplied to the negative electrode chamber The negative electrode solution is configured to pass through the negative electrode made of the porous sheet,
Removed anode solution in the negative electrode chamber from the circulation往口, circulation pipe, with circulating back to the anode chamber via the circulation pump and a circulation Modokuchi,
A microbial power generation method comprising adjusting the pH of the negative electrode chamber to 7 to 9 by adding condensed water taken out from the positive electrode chamber to a negative electrode solution flowing through the circulation pipe. A negative electrode chamber having a negative electrode, holding microorganisms, and holding a negative electrode solution containing an electron donor;
A positive electrode chamber provided with a positive electrode that is separated from the negative electrode chamber via a cation exchange membrane, and is in contact with the cation exchange membrane ;
Means for supplying an oxygen-containing gas to the positive electrode chamber;
In a microbial power generation apparatus comprising:
A circulation outlet and a circulation return port provided in the negative electrode chamber;
A circulation pipe connecting the circulation outlet and the circulation return port so as to circulate the negative electrode solution, and a circulation pump provided in the circulation pipe ;
The condensed water is taken out from the positive electrode chamber by adding to the negative electrode solution flowing through the circulation pipe, and a pH adjusting means for adjusting the pH of the negative electrode chamber 7-9,
The negative electrode is made of a conductive porous sheet made of graphite, titanium, or stainless steel, the negative electrode is in contact with the cation exchange membrane, the negative electrode is filled in the entire negative electrode chamber, and is supplied to the negative electrode chamber A microorganism power generation device, wherein the negative electrode solution is configured to pass through a negative electrode made of the porous sheet .

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