JPH0375237B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a methane fermentation device suitable for treating wastewater containing organic matter, and more particularly to a methane fermentation device that can perform efficient methane fermentation. [Prior art and problems to be solved by the invention] Currently, organic matter-containing wastewater discharged from cities, factories, etc. in Japan is mainly treated using aerobic organisms. However, in recent years, anaerobic methane fermentation treatment has attracted attention, and anaerobic treatment equipment for industrial wastewater has been put into practical use. The reasons for this include the fact that compared to aerobic treatment, the amount of electricity required for treatment is lower, it is possible to recover effective energy through gasification, and the amount of surplus sludge is small, reducing sludge treatment costs, resulting in energy savings. This is because it becomes possible to treat wastewater from the mold. Methane fermentation usually consists of a three-element biochemical reaction: hydrolysis → acid fermentation → methane fermentation.
Substrates such as high-molecular proteins and carbohydrates are reduced in molecular weight to higher fatty acids, which are further converted to lower fatty acids to produce methane, carbon dioxide, and the like. In this biochemical reaction process, the growth rate of methane-fermenting bacteria is extremely low, so it is necessary to avoid leaking the bacterial cells out of the system. Under these circumstances, in order to enable high-speed methane fermentation, it is necessary to maintain a high concentration of methane-fermenting bacteria in the bioreactor. In order to achieve high-speed methane fermentation, the concentration of microorganisms in the bioreactor is increased by filling the bioreactor with microbial carriers, allowing the microorganisms to adhere to them, and preventing the washout phenomenon of the microorganisms. It is necessary to allow efficient methane fermentation to occur. Currently, microbial carriers include inorganic carriers such as porous ceramics, sand, activated carbon, and diatomaceous earth, as well as organic carriers such as plastic plates or particles, and Raschig rings, but none of them are capable of sufficiently attaching bacterial bodies. , satisfactory results have not been obtained. [Means and effects for solving the problem] Therefore, the present inventors conducted intensive research aimed at realizing a high-performance bioreactor for methane fermentation that solved the above problems, and found that the bioreactor could be used as an acid fermenter. A methane fermentation tank is used, each tank is filled with a specific nonwoven fabric and a microorganism carrier, and the carrier supports methane fermentation bacteria, and a circulation means is used to form an upward flow in each tank. The present invention was completed based on this knowledge. That is, the present invention provides a methane fermentation apparatus for methane fermentation of organic matter-containing wastewater, in which the methane fermentation apparatus is divided into an anaerobic acid fermentation tank and a methane fermentation tank, and the acid fermentation tank and the methane fermentation tank are each filled with microorganisms supported on a nonwoven carrier made of plastic fibers having a specific gravity of 1.0 or more, and each of the acid fermenter and the methane fermenter is equipped with a circulation means for forming an upward flow. The present invention provides a methane fermentation device characterized by: Hereinafter, the present invention will be explained in detail with reference to the drawings. The apparatus of the present invention basically consists of two tanks: an acid fermenter and a methane fermenter. Figures 1 a to c show one embodiment of the acid fermenter used in the present invention, Figure 1 a is a top plan view of the acid fermenter, and Figure 1 b is a vertical cross section of the acid fermenter. Figure 1c is a partially cutaway lower plan view of the acid fermenter. Moreover, FIGS. 2 a to c show one embodiment of the methane fermentation tank used in the present invention, FIG. 2 a is a top plan view of the methane fermentation tank, and FIG. 2 b is a top plan view of the methane fermentation tank. The vertical sectional view and FIG. 2c are a partially cutaway lower plan view of the same methane fermentation tank. In the figure, numeral 1 is an acid fermenter, and the acid fermenter 1
Usually, the external shape is cylindrical or prismatic, and FIG. 1 shows a prismatic cylindrical shape. This acid fermentation tank 1 has a perforated plate 2 in the upper part that prevents the nonwoven fabric carrier described later from flowing out, and has a perforated plate 3 in the lower part that maintains the nonwoven fabric carrier. The external shapes of these perforated plates 2 and 3 are similar to that of the acid fermenter 1, and are slightly smaller than the acid fermenter 1. The perforated plate 2 and the perforated plate 3 may literally be plate-shaped with holes, but are preferably grid-shaped as shown. Microorganisms supported on a nonwoven fabric carrier are filled between the perforated plate 2 and the perforated plate 3. In the figure, reference numeral 4 is a layer filled with microorganisms supported on a nonwoven fabric carrier. Details of this nonwoven fabric carrier will be described later. The filling rate of the nonwoven fabric carrier is preferably 50 to 90%, particularly 60 to 80%, of the volume between the perforated plates 2 and 3. If the filling rate is less than 50%, although sufficient flow occurs during backwashing, the amount of bacterial cells adhering to the nonwoven fabric carrier decreases, which is not preferable because the reaction efficiency decreases. Meanwhile, the filling rate is 90%
If it exceeds this amount, sufficient flow of the nonwoven fabric carrier will not be achieved when excess bacterial cells adhering to the nonwoven fabric carrier are peeled off by backwashing, and a sufficient cleaning effect will not be obtained, which is not preferable. In the present invention, a wastewater supply pipe 5 and a wastewater supply pump 6 for supplying wastewater containing organic matter (raw wastewater) to the acid fermentation tank 1 are provided below the lower perforated plate 3. . Therefore, the waste water passes through the waste water supply pipe 5 and the waste water supply pump 6,
Perforated pipe 7 installed under the lower perforated plate 3
The acid flows upwardly through the acid fermenter 1. Furthermore, in the present invention, apart from this, a circulation means for forming an upward flow in the acid fermentation tank 1 is provided below the lower perforated plate 3. This circulation means specifically consists of a circulation pipe 8 and a circulation pump 9, and the treated water above the upper perforated plate 2 is passed through the circulation pump 8 and the circulation pump 9 and treated by the perforated pipe 10. Circulate some of the water. The above-mentioned drainage supply pipe 5, drainage supply pump 6, perforated pipe 7, circulation pipe 8, circulation pump 9
and perforated pipe 10, an upward flow is formed in the acid fermenter 1. Here, the flow velocity of the upward flow formed by the above means (the total flow velocity of the drainage flow velocity and the circulating water flow velocity) LV
is 6 to 8 m/hr before gas generation begins.
It is necessary to do the above. above this range
When the LV value is taken, there is no dead zone within the acid fermentation tank 1, and contact between waste water and circulating water and the microorganisms supported on the nonwoven fabric carrier is carried out extremely efficiently throughout the tank. Once gas starts to be generated from the acid fermenter 1, the LV value may be lowered to less than 6 to 8 m/hr because mixing by gas is performed. Since the acid fermenter 1 uses a nonwoven fabric carrier as a fixed bed as described above, the carrier becomes clogged due to proliferation of bacterial cells. Therefore, it is necessary to periodically backwash the carrier, and a backwashing means for this purpose is provided below the lower perforated plate 3 of the acid fermenter 1. The method of backwashing is to increase the flow rate of the upward flow in the tank.
A method of increasing the LV and a method of supplying blown gas into the tank are conceivable, and the acid fermenter 1 of the present invention uses both to eliminate clogging. Therefore, in a broad sense, backwashing means includes means for increasing the flow velocity LV of the upward flow in the tank,
Here, we will discuss backwashing means in a narrow sense, that is, means for supplying blown gas into the tank. As the blowing gas, inert gas such as nitrogen or gas generated from inside the tank is used. In the present invention, as shown in the figure, a backwashing gas pipe 11 and a sparger 12 are provided at the bottom of the acid fermentation tank 1, and the backwashing gas passes through the backwashing gas pipe 11 and is transferred from the sparger 12 to the tank. blown inward. In the acid fermentation tank 1 having the above-described structure, organic matter in the waste water undergoes an acid fermentation reaction by microorganisms, and is led to the methane fermentation tank 15 at the subsequent stage through the treated water pipe 13. Further, the gas generated from the acid fermentation tank 1 is taken out from the gas pipe 14, and a part of it is used as the blowing gas for backwashing, if necessary. Separately from the acid fermentation tank 1, a methane fermentation tank 15 is provided at a subsequent stage connected thereto. The methane fermentation tank 15 usually has a cylindrical or prismatic external shape, and FIG. 2 shows a prismatic cylindrical type. This methane fermenter 15 has almost the same structure as the acid fermenter 1 described above, but is usually different from the acid fermenter 1 in the carrier filling rate and the shape of the carrier used. That is, the methane fermentation tank 15 has a perforated plate 16 and a perforated plate 17 at the upper and lower parts, respectively. The upper perforated plate 16 prevents the nonwoven fabric carrier from flowing out, and the lower perforated plate 17 prevents the nonwoven fabric carrier from flowing out. Maintained. These perforated plates 16 and 17 are similar to the perforated plates 2 and 3 in the acid fermentation tank 1. A space between the perforated plate 16 and the perforated plate 17 is filled with microorganisms supported on a nonwoven fabric carrier. In the figure, reference numeral 18 is a layer filled with microorganisms supported on a nonwoven fabric carrier. The filling rate of the nonwoven fabric carrier filled in this methane fermentation tank 15 is 70 to 100% of the volume between the perforated plates 16 and 17. This is because the methane-fermenting bacteria in the methane fermentation tank 15 grow slowly and are not as sticky as acid-fermenting bacteria, so that the microorganisms can be removed even without fluidization of the nonwoven fabric carrier. In the present invention, a supply pipe 1 for supplying water that has passed through the acid fermentation tank 1 to the methane fermentation tank 15 is provided.
9 is provided. This supply pipe 19 is directly or indirectly connected to the treated water pipe 13 of the acid fermenter 1, and is provided below the lower perforated plate 17. Therefore, the water that has passed through the acid fermenter 1 is
The treated water is led from the treated water pipe 13 to the supply pipe 19 and flows upward through the perforated pipe 20 installed under the perforated plate 17 at the bottom of the methane fermentation tank 15 . Here, the flow from the acid fermenter 1 to the methane fermenter 15 is performed by gravity. For this reason, sufficient consideration should be given to the positional relationship between the acid fermenter 1 and the methane fermenter 15, the positional relationship between the treated water pipe 13 and the supply pipe 19, etc. Furthermore, in the present invention, a circulation means for forming an upward flow in the methane fermentation tank 15 is provided below the lower perforated plate 17. Specifically, this circulation means consists of a circulation pipe 21 and a circulation pump 22, and the treated water above the upper perforated plate 16 is passed through the circulation pipe 21 and the circulation pump 22 and treated by the perforated pipe 23. Circulate some of the water. By the above-mentioned circulation means, the treated water pipe 13
Together with the flow of acid fermentation water due to the positional relationship between the supply pipe 19 and the like, an upward flow is formed in the methane fermentation tank 15. Here, the flow rate of the upward flow formed by the above means (the total flow rate of the acid fermentation water flow rate and the circulating water flow rate)
The LV needs to be 6 to 8 m/hr or more before gas generation begins. When the LV value is above this range, there is no dead zone within the methane fermentation tank 15, and the contact between the waste water (acid fermentation water) and circulating water and the microorganisms supported on the nonwoven fabric carrier is carried out extremely efficiently throughout the tank. . When gas starts to be generated from the methane fermentation tank 15, the LV value may be lowered to less than 6 to 8 m/hr because mixing by gas is performed. Like the acid fermenter 1, the methane fermenter 15 uses a nonwoven fabric carrier as a fixed bed, and therefore, over a long period of time, the carrier becomes clogged due to the proliferation of bacterial cells. Therefore, it is necessary to periodically backwash the carrier, and a backwashing means for this purpose is provided below the lower perforated plate 17 of the methane fermentation tank 15. The backwashing method is similar to the backwashing method of the acid fermentation tank 1, and is carried out by increasing the flow rate LV of the upward flow in the tank and supplying blown gas into the tank. In order to supply blown gas into the tank, a backwashing gas pipe 24 and a sparger 25 are provided at the bottom of the methane fermentation tank 15. A blowing gas using an inert gas such as nitrogen or a gas generated from inside the tank passes through a backwashing gas pipe 24 and is blown into the tank from a spargeer 25. In the present invention, organic matter in wastewater undergoes acid fermentation by microorganisms in the acid fermenter 1, becomes gas such as methane in the methane fermenter 15, and is taken out from the gas pipe 27. Furthermore, the methane fermentation treated water is discharged to the outside through the treated water pipe 26. Now, regarding the nonwoven fabric carrier used as a microorganism carrier in the present invention, this nonwoven fabric carrier is made of a nonwoven fabric having countless complicated spaces. This non-woven material has a specific gravity that is higher than that of water.
It is made of plastic fiber of 1.0 or more. Since the bacterial flora that govern the reactions of acid fermentation and methane fermentation are different, it is necessary to select materials that match the bacterial flora. Specific examples include polyvinylidene chloride, polyvinyl chloride, nylon, vinylon, etc. Among them, polyvinylidene chloride is easily attached to both microorganisms involved in acid fermentation and microorganisms involved in methane fermentation. preferable. To summarize the characteristics of nonwoven fabric carriers, 1) Microorganisms can be immobilized at high concentration within the complex spaces woven by nonwoven fabrics; 2) The size of the spaces is determined by the thickness of the threads;
It can be freely adjusted by adjusting the degree of compression, etc., and can be applied to the immobilization of various bacterial bodies; 3) The actual volume occupied by the carrier is small, and the amount of water held up is extremely large; 4) It is overly effective; 5) It is difficult to process. 6) It is possible to select from various synthetic resin materials suitable for bacterial attachment; 7) It can be made into a rigid body and is easy to handle; 8) It is lightweight and has excellent economic efficiency. can. For the above reasons,
Microbial carriers made of nonwoven fabric are extremely suitable for immobilizing microbial cells. When performing methane fermentation using such a nonwoven fabric as a microbial carrier, the opening of the nonwoven fabric is important in order to allow bacterial cells to adhere at a high concentration. Nonwoven fabrics have countless complex spaces created by the threads of their material, but the inventors assumed that nonwoven fabrics are composed of anhydrous spaces with the threads forming a cubic lattice. Then, a conceptual diagram of a cubic lattice model as shown in FIGS. 3a to 3c was considered. Figure 3a is an external view of the nonwoven fabric, Figure 3b is a model diagram (n = 3),
Figure 3c is a cubic grid diagram. In the figure, α indicates the opening, β indicates the opening from the center of the yarn diameter, and l indicates the length of one side of the nonwoven fabric carrier. Using this cubic lattice model, in the present invention, the mesh opening was calculated using the following formula assuming that a regular cubic nonwoven fabric with a side of 1 cm forms a cubic lattice divided into n pieces. As a result, the opening of the nonwoven fabric carrier filled in the bioreactor for acid fermentation was 2 to 9 mm, and the opening of the nonwoven fabric carrier filled in the bioreactor for methane fermentation was 2 to 9 mm.
It has been found that a thickness of 0.6 to 3 mm is preferable (the details are disclosed in Japanese Patent Application No. 63-6836). In addition, when calculating the eye opening,
d: Thickness of thread (cm), L: Total length of thread (cm), l:
Length of one side of nonwoven fabric carrier (cm), n: number of divisions (-), γ: true specific gravity of material (g/cm ³ ), γa: bulk specific gravity of nonwoven fabric (g/cm ³ ), W: regular cube It was defined as the weight of the nonwoven fabric (g), α: opening (cm), and β: opening (cm) from the center of the yarn diameter. First, the total length of the thread can be expressed as the product of the side length of the unit cubic lattice and the number of sides. L=βx3n(n+1) ² …(1) β=l/n …(2) From equations (1) and (2), n=√3−1 …(3) Also, the weight of the regular cubic nonwoven fabric is as follows ( 4) It can be expressed by Eq. W=L×1/4πd ² ×γ (4) The bulk specific gravity of the nonwoven fabric can be expressed by the following equation (5). γa=W/l ³ (5) From the above equations (4) and (5), L=−kl ³ (6) where k=(γa/γ)/1/4πd ² (7). From equations (7) and (3) Therefore, the eye opening α can be expressed by the following equation (9). In the present invention, the shape of the nonwoven fabric carrier is preferably one that allows continuous production and is produced at low cost. The shapes of commonly used nonwoven carriers are shown in Figures 4a-e. Figure 4a shows a cylindrical shape, Figure 4b shows a square shape, Figure 4c shows a spherical shape, Figure 4d shows a hollow cylindrical shape, and Figure 4e shows a plastic substrate and a non-woven fabric. The figure shows a cubic module consisting of alternating combinations of . In the present invention, the shapes of the nonwoven fabric carriers may be the same in the acid fermenter 1 and the methane fermenter 15, but preferably different shapes are used. In other words, from the standpoint of reaction efficiency, the shape shown in Figure 4a is good, but this shape is better than the shape shown in Figure 4A in terms of fluidity.
It is inferior to the one in Figure A. Therefore, the acid fermenter 1, in which fluidity is particularly required during backwashing of carriers, should have a cylindrical shape as shown in FIG. It is preferable to use a coated one, and to use one having a shape as shown in FIG. 4e for the methane fermentation tank 15. In addition, since nonwoven fabric is soft, some measures are required to use it as a carrier. Usually, it is necessary to use a nonwoven fabric whose surface is heated to make it rigid. However, in the case of the shape as shown in Fig. 4e,
Because the plastic substrate supports the module's strength, there is no need to heat it to make it rigid. [Example] Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto unless it exceeds the scope of the present invention. Example 1 Methane fermentation device having an acid fermenter and a methane fermenter (fixed bed methane fermentation bioreactor)
A bench plant using this was installed at an oil/fat/protein manufacturing factory, and a field test of long-term continuous anaerobic methane fermentation was conducted. This wastewater has a BOD of approximately 1000
The equipment was designed under conditions of a flow rate of 7.5 m ³ /day and a water temperature of 30°C. The contents of the experiment will be explained below according to the flow sheet shown in FIG. (1) Explanation of flow sheet After wastewater (raw water) is stored in the adjustment tank 101, it is pumped to the acid fermentation tank 103 by the raw water pump 102.
supplied to Inside the acid fermentation tank 103, liquid is circulated in an upward flow by a circulation pump 104.
After a residence time of 3.2 hours, the acid fermentation treated water flows into the methane fermentation tank 106 through an external pipe (treated water pipe) 105. In the methane fermentation tank 106 as well, as in the acid fermentation tank 103, the liquid is circulated in an upward flow by a circulation pump 107.
After a residence time of 6.4 hours, the overflowed methane fermentation treated water is temporarily stored in the treated water tank 108 and discharged by the treated water pump 109 as appropriate. In addition, microorganisms growing in the bioreactor are collected as surplus sludge from the bottoms of the acid fermentation tank 103 and the methane fermentation tank 106 through the piping 1.
10, 111 so that it can be pulled out as appropriate. The extracted sludge is stored in a sludge tank 112 and sent to a sludge treatment facility by a sludge pump 113. On the other hand, the gas generated from the bioreactor passes through gas pipes 114 and 115, respectively, and flows into deflow towers 116 and 116' filled with an iron oxide catalyst, where malodorous components such as hydrogen sulfide are removed. Next, the gas exiting the deflow towers 116, 116' is led to a cleaning tower 117, where trace amounts of remaining malodorous components are absorbed by an aqueous solution containing alkali as its main component. Destreaming towers 116, 116' and washing tower 1
A cushion tank 118 located in the middle of the bioreactor 17 stores a small amount of generated gas to prevent the inside of the bioreactor from becoming negative pressure and sucking the atmosphere when sludge is drawn out. The generated gas from which malodorous components have been removed in this way can be used as energy. (2) Experimental equipment The main equipment of the experimental equipment shown in the flow sheet of Figure 5 will be explained. Adjustment tank 2000mmφ×2000mmH, volume 6.3m ³ , effective volume 5.0m ³ x 2 fixed bed methane fermentation bioreactor [acid fermentation tank] The structure shown in FIG. 1 was used. a) Dimensions Γ900mm×750mm×1800mmH, volume ^1.2m3 ,
Effective volume 1.0m ³ Volume of perforated plate interval: 900mm x 750mm x 1500
mmH, volume 0.71 m ³ b) Nonwoven fabric carrier shape Cylindrical carrier shown in Figure 4 a (50 mmφ x 50
mmL), the circumference of which was covered with a perforated plastic film (plastic film hole diameter: 7.8 mmφ, plastic film porosity: 30%) was used. c) Filling amount and ratio of nonwoven fabric carrier Filling amount 0.54 m Filling rate per volume between ³ perforated plates 76% d) Aperture of nonwoven fabric carrier A nonwoven fabric carrier with an aperture of 3.6 mm was used. [Methane fermentation tank] A tank having the structure shown in FIG. 2 was used. a) Dimensions Γ900mm×900mm×3000mmH, volume ^2.4m3 ,
Effective volume 2.0m ³ Volume of perforated plate spacing: 900mm x 900mm x 2050
mmH, volume 1.7 m ³ b) Non-woven fabric carrier shape A cubic module combining a plastic substrate and non-woven fabric as shown in Figure 4e was used. Note that the plastic substrate used had an uneven surface. The thickness of this board is 0.7mm, the spacing between boards is 33mm, the thickness of the nonwoven fabric is 20mm, and the unit module dimensions are
It was 450mm x 450mm x 500mm. c) Filling amount and ratio of nonwoven fabric carrier Filling amount 1.7 m Filling rate per volume between ³ perforated plates 100% d) Aperture of nonwoven fabric carrier A nonwoven fabric carrier with an aperture of 2.1 mm was used. [Treatment water tank] 1800mmφ×2100mmH, volume 5m ³ [Sludge tank] 1800mmφ×2100mmH, volume 5m ³ [Desulfurization tower] Acid fermentation tank 103 and methane fermentation tank 10
Desulfurization towers 116 and 11 used for each of 6
6′ has the same dimensions (300mmφ×1750mmH, volume
120) and filled with iron oxide 70. [Cushion tank] Volume: 140 [Cleaning tower]: 200 mmφ x 2000 mmH, volume: 60 (3) Experimental method and results At the start of operation, digested sludge was used as a seed culture and was introduced into the acid fermenter 103 and the methane fermenter. The pH of each tank was controlled within the range of 6.0 to 6.7 for the former and 7.2 to 7.8 for the latter. Thereafter, microbial growth operation was conducted for half a year, and a steady state was reached, so experiments were conducted under the designed conditions for one month continuously. The average values of the one month experiment are shown below.

【table】

【table】

〔Effect of the invention〕

According to the present invention, high energy can be recovered while effectively removing BOD. Furthermore, wastewater treatment can be carried out extremely efficiently since no aeration power is required.

[Brief explanation of drawings]

Figures 1 a to c show one embodiment of the acid fermenter used in the present invention, Figure 1 a is a top plan view of the acid fermenter, and Figure 1 b is a vertical cross section of the acid fermenter. Figure 1c is a partially cutaway lower plan view of the acid fermenter. Moreover, FIGS. 2 a to c show one embodiment of the methane fermentation tank used in the present invention, FIG. 2 a is a top plan view of the methane fermentation tank, and FIG. 2 b is a top plan view of the methane fermentation tank. The vertical sectional view and FIG. 2c are a partially cutaway lower plan view of the same methane fermentation tank.
In addition, in the figure, code 1 is an acid fermentation tank, code 2 is a (upper) perforated plate, code 3 is a (lower) perforated plate, code 4 is a microorganism carrier packed bed, code 5 is a wastewater supply pipe, code 6
1 is a drainage supply pump, 8 is a circulation pipe, 9 is a circulation pump, 11 is a backwash gas pipe, 1
2 is a sparger, 13 is a treated water pipe,
15 is a methane fermentation tank, 16 is an (upper) perforated plate, 17 is a (lower) perforated plate, 18 is a microorganism carrier packed bed, 19 is a supply pipe, 21 is a circulation pipe, and 22 2 is a circulation pump, 24 is a backwash gas pipe, 25 is a sparger, and 2 is a sparger.
6 is a treated water pipe. Figures 3a to 3c are conceptual diagrams of the cubic lattice model,
FIG. 3a is an external view of the nonwoven fabric, FIG. 3b is a model diagram (n=3), and FIG. 3c is a cubic lattice diagram. In addition,
In the figure, the symbol α indicates the opening, β indicates the opening from the center of the yarn diameter, and l indicates the length of one side of the nonwoven fabric carrier. Figures 4a to 4e show various shapes of the nonwoven fabric carrier; Figure 4a is cylindrical, Figure 4b is square, Figure 4c is spherical, and Figure 4d is spherical. hollow cylindrical,
Figure 4e shows a cubic module consisting of alternating plastic substrates and non-woven fabrics. Fifth
The figure is a flow sheet in an example of the present invention. In the figure, numeral 101 is a regulating tank, numeral 103 is an acid fermentation tank, numeral 104 is a circulation pump, and numeral 105 is
1 is a treated water pipe, 106 is a methane fermentation tank, and 1 is a methane fermentation tank.
07 is a circulation pump, 108 is a treated water pipe, 112 is a sludge tank, 114, 115
116 and 116' are respective desulfurization towers, 117 is a cleaning tower, and 118 is a cushion tank.

Claims (1)

[Scope of Claims] 1. In a methane fermentation device for methane fermentation of wastewater containing organic matter, the methane fermentation device is divided into an anaerobic acid fermentation tank and a methane fermentation tank, and the acid fermentation tank and the methane fermentation tank are divided into an anaerobic acid fermentation tank and a methane fermentation tank. Each of the fermenters is filled with microorganisms supported on a nonwoven carrier made of plastic fibers having a specific gravity of 1.0 or more, and each of the acid fermenter and the methane fermenter has a circulation means for forming an upward flow. A methane fermentation device characterized by being equipped with. 2. The methane fermentation tank according to claim 1, wherein the acid fermenter and the methane fermenter each have a perforated plate in the lower part for maintaining the nonwoven fabric carrier, and each has a perforated plate in the upper part to prevent the nonwoven fabric carrier from flowing out. Fermentation equipment. 3. The methane fermentation apparatus according to claim 2, wherein the acid fermenter and the methane fermenter are each provided with a backwashing means, a circulation means, and a waste water supply pipe below the lower perforated plate.