KR101575790B1 - Anaerobic digester equipped with bioelectrochemical apparatus and method for anaerobic digestion of organic waste using the anaerobic digester - Google Patents

Abstract

The present invention relates to an apparatus and a method for increasing efficiency of an anaerobic digestion tank used for treating waste water or slurry-type waste with a high content of organic materials by using a bioelectrochemical device. An electrode device, comprising electrode modules which include an oxidation electrode and a reduction electrode on which microorganisms having electric activity adhere and grow and are integrally joined to have a separation membrane therebetween, is installed in the anaerobic digestion tank. A potential difference between the oxidation electrode and the reduction electrode is maintained to be 0.2-0.6 V by using external power. The concentration of a product from acid generation reaction of content in the digestion tank is maintained to be low as oxidation reaction of organic acid or the like is accelerated by anaerobic microorganisms which adhere and grow on the surface of the oxidation electrode and have electric activity. Therefore, hydrolysis and the acid generation reaction are accelerated by floating microorganisms. The speed of methane gas generation and a rate of organic material reduction can be significantly increased by accelerating methane generation reaction as electrons, protons, and carbon dioxide are bound to each other on the reduction electrode.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anaerobic digestion apparatus having an anaerobic digestion apparatus and an anaerobic digestion apparatus using the same,

The present invention relates to an anaerobic digestion apparatus, and more particularly, to an anaerobic digestion apparatus and an anaerobic digestion method in which anaerobic digestion performance of organic waste is greatly improved by providing a bioelectrochemical device.

Anaerobic digestion can be used to treat various organic wastewater or slurry organic wastes with high organic matter content such as sewage sludge, food waste, agricultural and animal wastes, manure, wastewater, pulp and paper wastewater, landfill leachate, etc. and to produce methane gas as a byproduct It is a traditional technology that has been used for over 100 years.

The anaerobic digestion process of organic matter is usually carried out by a hydrolysis step in which a polymer organic substance is decomposed into monomers, an acid production step in which an acid producing bacteria is converted into various organic acids including acetic acid and carbon dioxide and hydrogen using hydrolysis products, And a methane generation step of converting acetic acid and hydrogen, which are products of the reaction, into methane.

The anaerobic degradation step of the organic material is as follows: i) When the organic matter to be anaerobically digested is composed of a polymer material, the hydrolysis step may be a step of speeding up the entire anaerobic digestion reaction. ii) In the case of the acid production step, the optimal pH is around 6.5, and the acid production reaction in the anaerobic digestion tank generally proceeds relatively fast as compared with the other reaction steps. However, the hydrolysis reaction is highly inhibited by the product, so that the reaction rate is greatly slowed when the concentration of the acid production reaction product such as monosaccharide or hydrogen or organic acid is high in the anaerobic digestion tank. iii) In the methanogenesis stage, the growth rate is relatively slow, and the biological activity of these methanogens is sensitive to environmental conditions such as toxic substances, temperature and pH. Unlike the production reaction, it is known to be about 6.8-7.5. Particularly, methane-producing bacteria are classified into acetic acid-using methane-producing bacteria and hydrogen-utilizing methane-producing bacteria, depending on usable substrates. In the case of acetic acid-using methane bacteria, when acetic acid concentration or hydrogen partial pressure is high in digestion tank, The production reaction is often the rate-limiting step of the total anaerobic digestion process.

Thus, the realization of high-efficiency anaerobic digestion depends on how to overcome the hydrolysis and methanogenesis stages, which are the rate-limiting stages, and how the anaerobic degradation reactions consisting of the above steps are coordinated in the anaerobic digester.

In the last 30-40 years, researchers in the field of anaerobic digestion have sought to improve the efficiency of hydrolysis by pretreatment such as heat treatment, ultrasonic treatment, acid or base treatment when the organic matter to be anaerobically digested is a polymer substance. In addition, anaerobic filter (AF), upflow anaerobic sludge blanket (UASB) and the like, which utilize the immobilization ability of anaerobic microorganisms to retain a relatively large amount of methanogenic bacteria when the methanogenic reaction is in the rate- The same high rate anaerobic digestion processes have been developed and widely used. Particularly, anaerobic membrane bioreactor (AnMBR), which is advantageous for maintaining high concentration of anaerobic microorganisms in a digester, can be used to treat anaerobic digestion technology of low concentration organic wastewater such as sewage as well as high concentration organic wastewater. Respectively.

However, in the case of anaerobic digestion of organic wastes containing a large amount of solid polymeric substances such as sewage sludge, livestock wastewater, food waste, etc., a large amount of energy is required for the pretreatment used to improve the efficiency of the hydrolysis step, Techniques for increasing the rate of methanogenic reaction by increasing the concentration of methanogenic bacteria, such as anaerobic sorbent or upflow anaerobic blanket reactors, may allow solids contained in the incoming wastes to accumulate in the digester, thereby retaining a sufficient amount of methanogenic bacteria in the digester And it is difficult for the anaerobic membrane-bound bioreactor to be an effective technique that can be used in the field unless the membrane clogging is fundamentally solved.

Recently, attempts have been made to solve the problem of the above anaerobic digestion tank by using microbial electrolysis cell technology, which is a type of bioelectrochemical cell.

If an oxidizing electrode and a reducing electrode are installed in the anaerobic digestion tank and a constant potential difference is maintained between the oxidizing electrode and the reducing electrode, the oxidizing reaction and the methane forming reaction can be performed by the microorganisms adhering to the oxidizing electrode and the surface of the reducing electrode, respectively have. Based on these principles, there have been reported microbial electrolytic cell technologies for producing methane gas in an anaerobic digestion tank. Most of them are two chamber type microorganism electrolytic cell technologies, which are working electrode for generating methane gas, A counter electrode for supplying a working electrode is provided in a separate space separated by a separation membrane and a substrate is injected only into a space where the working electrode is installed (Sasaki et al., 2010; Villano et al., 2010; Sasaki et al., 2011 Villano et al., 2011; Jiang et al., 2013; Sasaki et al., 2013). In addition, basic research results have also been reported in the case of a single chamber type in which a working electrode and a counter electrode are provided in the same reaction tank, but most of them do not use a separation membrane for separating the electrodes, The performance was not good due to the long distance (Guo et al., 2013).

Most of the technologies using the microbial electrolytic cell are based on the microbial electrolytic cell technology for the production of biohydrogen, which has been studied in the past, but there is a limit to apply directly to the anaerobic digestion tank for methane gas production.

Guo, X., Liu, J., Xiao, B., Enhancement of hydrogen and methane production from the anaerobic digestion of sewage sludge in single-chamber membrane-free microbial electrolysis cells, International journal of hydrogen energy, 38, 1342-1347 (2013). Jiang, Y., Su., M., Zhang, Y., Zhan, G., Tao, Y., Li, D., systems for simultaneous production of methane and acetate from carbon dioxide at a high rate, International journal of hydrogen energy, 38, 3497-3502 (2013). Sasaki, K., Sasaki, D., Morita, M., Hirano, S. I., Matsumoto, N., N., Ohmura, and Igarashi, Y., system stabilizes methane fermentation from Sasaki, K., Morita, M., Sasaki, D., Hirano, SI, Matsumoto, N., Ohmura, N., and Igarashi, Y., Communities on the Electrodes of Bioelectrochemical Reactors without Membranes, Journal of Bioscience and Bioengineering , ≪ / RTI > 111 (1), 4749 (2011). AMB Express, 3 (2004), pp. 243-244 (2003). Acknowledgments This work was supported by a grant from the National Institute of Advanced Industrial Science and Technology (AIST) (17), 1-9, (2013). Song, Y. C., Kwon, S. J., Woo, J. H., and thermophilic temperature co-phase anaerobic digestion compared with single-stage mesophilic- and thermophilic digestion of sewage sludge, Water Research, 38, 165316 (2004). Villano, M., Aulenta, F., Ciucci, C., Ferri, T., Giuliano, A., Majone, M., reduction in CO2 to CH4 via direct and indirect extracellular electron transfer by a hydrogenophilic methanogenic culture, Bioresource Technology , 101, 30853090 (2010). Villano, M., Monaco, G., Aulenta, F., Majone, M., assisted methane production in a biofilm reactor, Journal of Power Sources, 196, 94679472 (2011).

An object of the present invention is to provide an anaerobic digestion apparatus having a bioelectrochemical device suitable for anaerobic digestion of organic wastes.

Another object of the present invention is to improve the anaerobic digestion efficiency by promoting the anaerobic decomposition reaction by constituting the bioelectrochemical device considering the anaerobic decomposition step in the anaerobic digestion of the organic waste.

Other objects and technical features of the present invention will be more specifically described in the following detailed description.

To achieve the above object, according to the present invention, there is provided a digestion tank, comprising: a digester to which slurry organic waste flows; an electrode unit installed inside the digester; a plurality of electrode modules each having an oxidation electrode, And a stirring device for mixing organic wastes introduced into the digester, wherein the potential of the oxidizing electrode is kept higher than the potential of the reducing electrode by 0.2 to 0.6 V An anaerobic digestion apparatus having a bioelectrochemical device is provided.

The area of the oxidizing electrode and the reducing electrode of the electrode module may be 1 to 20 m ² per 1 m ³ of the digestion tank. The plurality of electrode modules may be installed in the digester at intervals of 1 to 30 cm .

The electrode module is preferably installed as much as possible on an area basis, but it is preferable to install the electrode module vertically or vertically so as to facilitate discharge of the biogas generated without interfering with the fluid flow inside the digester.

The oxidizing electrode and the reducing electrode may be formed of any one selected from carbon felt, carbon cloth, carbon fiber cloth, expanded graphite, and carbon nanotube, or a composite thereof, May be modified by an electrophoresis method by immersing in a mixed solution of a carbon nanotube, a nickel compound, a polyethyleneimine, or an adhesive polymer so as to improve electrical conductivity and biocompatibility, and applying a voltage thereto.

The reducing electrode can be used by attaching a transition metal catalyst such as platinum or nickel to the surface, and the oxidizing electrode can be used by attaching a mixture of carbon nanotube and expanded graphite.

The electrode module may be integrated as a separator by arranging a water permeable fabric or a porous plate between the oxidizing electrode and the reducing electrode.

The present invention is also characterized in that a plurality of electrode modules in which an oxidation electrode, a separation membrane, and a reduction electrode are integrally combined are disposed in a digestion tank, a slurry-type organic waste is introduced into the digestion tank and then stirred, Wherein the organic waste is subjected to anaerobic digestion by supplying power to the electrode to maintain the potential of the oxidizing electrode higher than the potential of the reducing electrode by 0.2 to 0.6V.

When the contents of the anaerobic digestion tank are mixed with the anaerobic digestion tank equipped with a bioelectrochemical device by mechanical or gas circulation method, the concentration polarization of the electrode surface can be mitigated, so that the surface reaction of the electrode is further promoted and the anaerobic digestion efficiency is further improved Can be improved.

When the subject to be digested by the anaerobic digestion tank according to the present invention is sewage sludge according to the present invention, HRT is suitable for 5 to 30 days. However, when the biodegradability of the target waste is as large as that of food waste, HRT Even with a short operation time of 0.5 to 5 days, excellent anaerobic digestion efficiency can be obtained.

As the HRT of the anaerobic digestion tank according to the present invention is increased, the VS loss is increased. Therefore, when the target waste is a material having poor biodegradability or when the VS loss is to be increased, You can also drive with work.

The anaerobic digestion tank equipped with the bioelectrochemical device according to the present invention according to the present invention is installed separately on the outside of the conventional anaerobic digestion tank and the contents digested in the conventional anaerobic digestion tank are circulated to the anaerobic digestion tank equipped with the bioelectrochemical device according to the present invention The same effect to be pursued in the present invention can be exhibited.

According to the present invention, by providing the bioelectrochemical device in the anaerobic digestion tank, the oxidation reaction of the organic acid is promoted by the electrically active anaerobic microorganism adhering and growing on the surface of the oxidizing electrode, thereby maintaining the organic acid concentration in the digestion tank low, The hydrolysis reaction of the material is facilitated and the electrons, protons and carbon dioxide are combined with each other at the reducing electrode to promote the methanogenic reaction, thereby greatly improving the performance of the anaerobic digestion process compared with the conventional complete mixed anaerobic digestion tank.

1 is a schematic view of an anaerobic digestion apparatus equipped with a bioelectrochemical device according to the present invention;
Fig. 2 is a schematic view showing an electrode device for installation in the anaerobic digestion tank according to the present invention.
FIG. 3 is a schematic view of an electrode module in which an oxidation electrode, a separation membrane,
FIG. 4 is a graph showing the relationship between the HRT and the operation time of the biogas generation amount
FIG. 5 is a graph showing changes in biogas component according to the HRT and the operation time in the embodiment of the present invention
FIG. 6 is a graph showing a comparison result of VS reduction ratio according to HRT in the embodiment of the present invention

The present invention proposes an anaerobic digestion apparatus and an anaerobic digestion method that improve the treatment efficiency of wastewater or slurry type waste having a high organic matter content by using a bioelectrochemical device.

By providing a bioelectrochemical device composed of an oxidizing electrode and a reducing electrode in which microorganisms having electrical activity adhered and growing is installed in the anaerobic digestion tank and the potential difference between the oxidizing electrode and the reducing electrode is maintained between 0.2 and 0.6 V, In the reduction electrode, a rapid reaction occurs in which carbon dioxide or carbonate produced by the oxidation electrode reaction is combined with protons or hydrogen and electrons to generate methane.

The decomposition reaction of the organic acid on the surface of the oxidation electrode prevents accumulation of the organic acid and hydrolyzed monomers in the anaerobic digestion tank and the reaction of the reduction electrode is performed by using hydrogen or hydrogen ion, The hydrogen partial pressure of the digester can be lowered. Further, as the concentration of hydrogen, carbon dioxide and organic acid, which are products of the acid production reaction, is lowered, the acid production reaction of the anaerobic digestion tank is further promoted and the concentration of the monomer produced by the hydrolysis reaction can be lowered.

Therefore, the hydrolysis reaction of the polymer organic substance is successively promoted, and the organic matter reduction rate and biogas generation of the anaerobic digestion tank for treating the organic waste are stably maintained. Also, since the carbon dioxide produced by the anaerobic oxidation reaction is continuously utilized by the reduction electrode reaction, the methane gas content of the biogas is greatly increased as compared with the conventional anaerobic digester.

Hereinafter, the anaerobic digestion apparatus having the bioelectrochemical device of the present invention and the anaerobic digestion method using the same will be described in detail with reference to the drawings.

1 is a schematic diagram of an anaerobic digester of organic waste with a bioelectrochemical device according to the present invention. A digester 1 for anaerobic digestion is a cylindrical reaction vessel equipped with an agitator, and a mechanical agitation device using a blade 2 and a motor 3 for mixing wastes introduced into the digester is installed. A non-mechanical circulating device may be used for stirring.

An electrode device 7 is provided in the digestion tank and a plurality of electrode modules in which an oxidation electrode 71, a separation membrane 73 and a reduction electrode 72 are integrally combined as shown in FIG. So that the horizontal flow and mixing of the contents of the digester by the agitator are minimized. The distance between the electrodes can be selected in the range of 1 - 30 cm depending on the particle size of the organic sludge to be treated.

The effect to be achieved in the present invention is the same even when the electrodes provided in the electrode device are vertical or in a different form when the flow of the contents of the digestion tank is in the vertical direction or the shape of the digestion tank is not cylindrical. Even if the anaerobic digestion tank of the present invention is cylindrical and the fluid in the digestion tank has flow in the horizontal direction while stirring, the effect to be achieved in the present invention is the same even when the electrode module is installed inside the digestion tank in the cylindrical shape.

The separation membrane between the oxidizing electrode and the reducing electrode is preferably used to prevent a short circuit caused by the contact between the oxidizing electrode and the reducing electrode, such as a nonwoven fabric or a porous plate. If the oxidizing electrode and the reducing electrode are sufficiently spaced apart to prevent the formation of a single path due to the direct contact between the oxidizing electrode and the reducing electrode, there is no need to use a separation membrane. However, in this case, Which is disadvantageous to oxidation electrode reaction and reduction electrode reaction.

A plurality of oxidizing electrodes provided spirally on the electrode device are connected in parallel using a lead wire 8 and then connected to the (+) terminal of the external power source device 9, and a plurality of return electrodes are also used And connect it to the (-) terminal of the external power supply.

The oxidizing electrode and the reducing electrode are carbon-based materials such as carbon felt, carbon cloth, carbon fiber fabric, expanded graphite, particulate graphite, and carbon nanotube, which are excellent in electrical conductivity, strong against corrosion, Or a combination thereof. Preferably, the surface of the carbon fiber fabric is immersed in a solution of a carbon nanotube, a nickel compound, or a polyethyleneimine or other polymer having excellent adhesive strength, and then modified by electrophoresis by applying a voltage. The surface of the reducing electrode is immobilized on the surface of the carbon-based electrode, such as platinum or nickel, to promote the reductive electrode reaction by reducing the activation energy of the reductive electrode reaction that produces methane from electrons, hydrogen ions and carbon dioxide desirable. It is preferable that the surface of the oxidized electrode is adhered to the surface of the carbon nanotube and the expanded graphite mixture by screen printing or the like, which has a good conductivity and a large specific surface area and is highly biocompatible.

Further, in order to improve the electrical conductivity of the oxidizing electrode and the reducing electrode, it is preferable to use a mesh or wire made of stainless steel or titanium, which is resistant to corrosion, as a current collector to be connected to the lead wire. A resistor connecting the oxidizing electrode and the reducing electrode may be provided to maintain the potential difference, or a potentiostat may be used instead of the external power source. It is advantageous in terms of energy efficiency to use a plurality of small-sized electrodes in parallel in the oxidation electrode and the reduction electrode, but the size of one electrode is not limited.

Surface area of the anode and reduction electrodes installed in the anaerobic digestion tank is wider biological electrochemical reaction of the electrode surface, but further promoted if the sewage to the anaerobic digestion substance sludge, food waste, etc. with respect to the volume of the anaerobic digestion tank 1m ³ 1 ~ 20 m ² is sufficient.

Organic waste in the form of slurry such as sewage sludge, food waste, livestock wastewater, etc. is injected through an inlet valve (4) installed at the bottom of the digester tank side, and the extinguished material is discharged through an outlet valve (5). The biogas containing methane gas is discharged through the gas discharge valve 6 above the digester.

The potential difference between the oxidizing electrode and the reducing electrode of the anaerobic digestion tank equipped with the bioelectrochemical device according to the present invention is maintained between 0.2 and 0.6 V by using an external power source as described above, and the hydraulic retention time (HRT) of the anaerobic digester, Is preferably operated between 0.5 and 50 days.

The anaerobic microorganisms that are suspended in the digestion tank cause hydrolysis and acid production reaction of the organic wastes introduced into the digestion tank equipped with the bioelectrochemical device according to this nickname.

On the surface of the oxidized electrode, the organic acid, which is the product of the hydrolysis and the acid production reaction, is decomposed by the electronically active microorganisms adhering to the surface of the electrode to generate hydrogen ions, electrons, and carbon dioxide.

At this time, the electrons are transferred to the oxidizing electrode and moved to the reducing electrode. Carbon dioxide and hydrogen ions move to the reducing electrode surface using the contents of the anaerobic digestion tank as a medium.

In the reduction electrode, hydrogen ions, electrons, and carbon dioxide are combined with each other to produce methane as shown in the following equation.

Assuming that the concentration of acetic acid and bicarbonate ion is 0.05M, the redox potentials of the oxidation electrode reaction and the reduction electrode reaction are theoretically -0.289V and -0.248V, respectively, as shown in the above equation. In the standard state, the potential for the reduction electrode reaction at pH 7 is theoretically known as -0.244 V (vs NHE). However, in an actual digestion tank, the electric potential required for advancing the reduction electrode reaction due to overcharge is different.

Thermodynamically, most biochemical reactions are promoted by biochemical reactions because the larger the free energy difference between the reactants and the products, the more energy available to the microorganisms becomes.

Where G is the difference in free energy (J) between the reactant and the product, and n is the number of electrons moved during the course of 1 mole of the redox reaction. F is the Faraday constant (96485.3 C / mol), and E is the redox potential (V).

When the oxidation electrode in the present invention is maintained at 0.2-0.6 V higher than the reduction electrode, the oxidized electrode potential in the digestion tank is higher than the theoretical potential -0.289 V and the reduced electrode potential is higher than the theoretical potential -0.248 V The decomposition reaction of organic acids or the like occurring on the surface of the oxidation electrode and the methane formation reaction occurring on the surface of the reduction electrode are greatly promoted. Thus, the methanogenic reaction no longer acts as a rate-limiting step in the total anaerobic decomposition step. In addition, due to the rapid decomposition of organic acids on the surface of the oxidized electrode, the organic acid concentration in the digestion tank contents is kept very low, and as a result, the hydrolysis and the acid production reaction are promoted.

Therefore, the anaerobic digestion efficiency of the anaerobic digestion tank equipped with the bioelectrochemical device according to the present invention is increased up to 7.2 times as compared with the conventional anaerobic digestion tank for treating the same waste as described later.

Example 1. Anaerobic digestion of sewage sludge using bioelectrochemical devices

An anaerobic digester with a 12 L capacity bioelectrochemical device was made of acrylic resin. In the anaerobic digestion tank, six rectangular electrode modules were integrally combined with the oxidation electrode, the nonwoven fabric and the reduction electrode as shown in FIG. Each of the oxidizing electrodes and the reducing electrode was connected in parallel using a lead wire and connected to the (+) terminal and the (-) terminal of the external power supply unit, and the potential of the oxidizing electrode was maintained at 0.3 V as compared with the reducing electrode .

The anaerobic digestion tank according to the present example was installed in a 35 ° C water bath and maintained at a constant temperature during operation. For the initial operation, the sludge collected from the anaerobic digestion tank of the sewage sludge was filled with about 30% of the effective capacity of the digester. During the operation of the anaerobic digester, the blades were rotated and agitated using a motor installed at the top. Y waste water sludge was injected once a day and discharged at the same amount of sludge as that of the inflow sludge injected once a day and operated at HRT 20 days, 15 days, 10 days and 5 days.

During the operation of the anaerobic digester, the current between the oxidizing electrode and the reducing electrode was monitored and the pH, alkalinity, VFA, TS, VS, TCOD and SCOD of the inflow and outflow sludge were analyzed at intervals of two days, Methane gas content was analyzed.

As shown in FIGS. 4 and 5, the biogas production amount and the methane gas content began to increase rapidly from about 45 days after the operation of the anaerobic digestion tank. The performance of the mesophilic anaerobic digestion tank according to HRT is shown in Table 1.

HRT (days) Amount of methane generated
(mL CH ₄ / L / d) Methane content (%) VS loss
(%) VFA concentration
(mg HAc / L) Remarks 20 412 77.3 70.5 410 Invention 15 498 77.1 63.6 340 10 719 75.6 60.2 340 5 1,289 74.9 52.4 765 20 days (medium temperature) 171.3 64.7 43.5 579 Water. Res., 38 (2004), 1653-1662 10 days (high temperature) 518.0 63.6 46.8 1,587

In HRT 20 days, the methane content in the biogas reached about 77%, and the methane emission was very high as 412 mL CH ₄ / Ld. The VFA concentration remained low at about 410 mg HAc / L. At this time, the content of methane gas reaching 77% is higher than 65% of the conventional mesophilic anaerobic digestion, and the VFA concentration maintained at about 410 mg HAc / L or lower shows the stability of the digester. In this example, the VS reduction at HRT of 20 days is 70.5%, which corresponds to the highest value of the VS reduction of the sewage sludge anaerobic digestion tank reported so far. The biologically degradable components contained in the sewage sludge are mostly decomposed .

When the HRT decreased to 15 days, 10 days and 5 days, the amount of methane generated increased to 1,289 mL CH ₄ / L / d due to the increase of the organic load, which was 7.52 times higher than that of the conventional mesophilic anaerobic digester , Which is about 2.5 times higher than the high temperature anaerobic digester operated with HRT for 10 days. The VS loss in the digestion tank was 52.4% on the 5th day of HRT, which was significantly higher than the 43.5% of the conventional anaerobic digestion tank of HRT 20 days reported in the literature and about 5.6% higher than 46.8% of the HRT 10 day anaerobic digestion tank (See FIG. 6).

Example 2. Anaerobic digestion at room temperature using a bioelectrochemical device

In order to evaluate the effect of the operation temperature on the performance of the anaerobic digester with the bioelectrochemical device of the present invention, the anaerobic digester of the present invention as in Example 1 was operated at HRT for 10 days to 25 ° C. The operation method, the contents of the digester, and the analysis of the biogas are the same as in the first embodiment. Table 2 shows the performance of the anaerobic digestion tank at room temperature.

Operating temperature Amount of methane generated
(mL CH ₄ / L / d) Methane content (%) VS loss
(%) VFA concentration
(mg HAc / L) Medium temperature (35) 498 77.1 63.6 340 At room temperature (25) 500 72.0 52.0 600

The amount of biogas generated after the operation temperature was changed to room temperature of 25 ° C in the anaerobic digester of the present invention operated at a middle temperature of 35 ° C was greatly decreased, but gradually increased from 2 days and gradually stabilized from 15 days. The performance of the anaerobic digestion tank of the present invention at about 25 ° C was about 82% of 35 ° C. These results indicate that the performance of the anaerobic digestion tank of the present invention can be operated at a room temperature without deteriorating the performance of the anaerobic digestion tank. If the anaerobic digestion tank of the present invention is operated at a high temperature of 55 ° C, hydrolysis and acid- It can be seen that the performance will be further increased.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Modified, modified, or improved.

1. Anaerobic digester 2. Blade
3. Motor 4. Inflow valve
5. Outlet Valve 6. Gas Outlet Valve
7. Electrode 8. Lead
9. External power supply 71. Oxide electrode
72. Reduction electrode 73. Membrane

Claims (10)

A single single-digestion tank into which slurry-type organic waste flows,
An electrode unit installed in the digester; a plurality of electrode modules having an oxidation electrode, a separation membrane, and a reduction electrode integrally combined;
A power source device for supplying power to the oxidizing electrode and the reducing electrode of the electrode module,
And an agitator for mixing the organic waste introduced into the digester,
The plurality of electrode modules are installed in a vertical spiral manner so as not to interfere with the vertical or flow of the fluid in the digester with intervals ranging from 1 to 30 cm in the digester,
And the potential difference between the oxidizing electrode and the reducing electrode is maintained at 0.25 - 0.5 V. The anaerobic digestion apparatus for methane generation comprising the bioelectrochemical device.
The method according to claim 1,
Wherein an area of the oxidizing electrode and the reducing electrode of the electrode module is 1 to 20 m ² per 1 m ³ of the digestion tank.
delete delete delete delete delete The method of claim 1, wherein
Wherein the electrode module is a separation membrane, and a water permeable fabric or a porous plate is disposed between the oxidizing electrode and the reducing electrode to integrate the membrane into an integrated bioreactor.
A single single-digestion tank into which slurry-type organic waste flows,
An electrode unit installed in the digester; a plurality of electrode modules having an oxidation electrode, a separation membrane, and a reduction electrode integrally combined;
A power source device for supplying power to the oxidizing electrode and the reducing electrode of the electrode module,
And an agitator for mixing the organic waste introduced into the digester,
Wherein the plurality of electrode modules are installed vertically or vertically in a spiral manner so as not to interfere with the flow of fluid in the digester with an interval ranging from 1 to 30 cm in the digestion tank. In the anaerobic digestion apparatus, Wherein the slurry-type organic waste is introduced into the digester after the electric potential difference of the electrode is maintained at 0.25 - 0.5 V, followed by stirring. The method for anaerobic digestion of organic waste for methane production.
The method of claim 9, wherein
And the HRT of the digester is operated between 0.5 and 50 days. The method for anaerobic digestion of organic waste for methane generation.

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