JP6396676B2 - Methane fermentation apparatus and treatment method of water-containing organic waste - Google Patents

Description

  The present invention relates to a methane fermentation apparatus and a method for treating hydrous organic waste.

  Here, the water-containing organic waste includes high-concentration organic wastewater generated at food factories, food raw material residues, and garbage generated from households, restaurants, convenience stores, etc., further livestock manure generated from the livestock industry, In addition, sewage sludge generated at a water purification plant and the like can be mentioned.

  In methane fermentation, which is a conventional anaerobic fermentation, both the method of injecting liquid and gas into the fermenter and the method of stirring with a propeller-type stirrer installed in the fermenter both provide propulsion to part of the fermenter. Since stirring is likely to occur, stirring unevenness is likely to occur, and when stirring is uncertain, suspended matter in the fermentation liquid often accumulates on the top of the fermentation liquid and forms scum. . When such a scum is formed, fermentation is delayed, there is a risk that the ecosystem of anaerobic microorganisms present in the fermenter will be destroyed and fermentation will not function. (Excerpted from Patent Document 1, paragraph 0004 with some edits).

  That is, in methane fermentation, undigested high-concentration waste liquid often comes out without being completely digested. Moreover, since there are many undigested substances, the surface of the scum is stagnated, the tank and the pipe are blocked by the accumulated matter, and it is necessary to stop the operation and perform cleaning.

In order to solve this problem, it has been proposed that the fermenter has an arm having a length reaching the head space as a structure capable of forming a head space. (Patent Document 1 Abstract, etc.)
However, even in this technique, it is necessary to provide a mechanical part that requires sealing performance on both side walls of the fermenter at both ends of the horizontal rotation shaft, and periodic maintenance is required.

Biogas produced by methane fermentation typically contains about 60 vol% methane (CH ₄ ), 40 vol% carbon dioxide (CO ₂ ), and about 0.2 vol% hydrogen sulfide (H ₂ S) ( (See Patent Document 3, paragraph 0003). This is because when the sulfur-containing compound is decomposed into microorganisms in the absence of oxygen, the sulfur component is reduced to hydrogen sulfide. When the concentration of hydrogen sulfide in the biogas increases, not only the quality of the biogas is lowered, but also the methane fermentation is inhibited.

  In such a case, a biological desulfurization tower that is cheaper than a dry desulfurization method using iron oxide or activated carbon is usually used (Patent Document 1, Paragraph 0005, Patent Document 2, Paragraph 0010, Patent Document 3, Paragraph 0005, etc.) ).

  And the sulfuric acid produced | generated in a biological desulfurization tower needs to be neutralized in order to increase the acidity of circulating water. It has been proposed to use ammonia produced as a by-product during biogas generation for this neutralization (summary of Patent Document 4).

JP 2006-7091 A JP 2012-115812 A JP 2013-139032 A

  The present invention has a simple structure that does not include a mechanical mechanism for stirring, has good stirring efficiency and can increase digestibility, and treatment of water-containing organic waste using the methane fermentation apparatus It aims to provide a method.

  As a result of diligent efforts to solve the above-mentioned problems, the present inventor has come up with a methane fermentation apparatus (1) and a water-containing organic waste treatment method (2) having the following configurations.

(1) storing a fermentation stock solution from water-containing organic waste and methane fermentation tank to an anaerobic fermentation, without a desulfurization tower for performing desulfurization was carried out or desulfurization desulfurization biogas from the methane fermentation tank in the desulfurization tower a methane fermentation apparatus Ru and a gas holder which,
The methane fermenter is
A vertical circulation partition wall, a contact bed filled in at least one of the inside and outside of the circulation partition wall, and a circulation pipe for circulating the fermentation stock solution supplied to the fermenter,
The circulation pipe includes a circulation pump and a suction injector in the circulation direction,
The suction injector is connected to a gas holder and a biogas so as to be suckable;
An injection pipe is connected to the tip of the circulation pipe, and an injection port of the injection pipe is arranged so as to face a lower opening inside or outside the circulation partition wall,
By injecting the fermentation stock solution biogas is aspirated mixture from the injection port, which was to generate a swirl flow across the circumfluence partition wall,
The desulfurization tower is
A microbial carrier is filled at the middle height of the tower, a liquid reservoir is provided below the microbial carrier, and a shower pipe is provided above the microbial carrier.
A liquid recirculation pipe connected to the liquid storage part of the desulfurization tower and connected to the shower pipe at the front part;
The liquid circulation pipe includes a circulation pump and a suction injector in the circulation direction,
Biogas can be introduced at a height position directly below the microbial carrier,
The microbial carrier is formed of a filling body of a flat reticular cylindrical body made of a synthetic resin having flexibility that can change flatness by water pressure .

(2) Water-containing organic waste, in the case of liquid or slurry, or hydrated to produce biogas by methane fermentation as a fermentation stock solution by crushing it if it is solid or contains a solid that does not form a slurry A method for treating organic waste,
While performing the said methane fermentation using the methane fermentation apparatus of said (1) provided with the desulfurization tower, the desulfurized digestive liquid which generate | occur | produces from the said desulfurization tower is introduce | transduced into an aerobic biological treatment tank, and also through a precipitation tank It is characterized by purifying to a pollution concentration that can be discharged into rivers.

FIG. 1 is an overall flowchart showing an example of a method for treating hydrous organic waste according to the present invention. (A) is a schematic elevation which shows the one aspect | mode of the methane fermenter used for a water-containing waste processing method, (B) is a BB sectional drawing of (A). (A) is a schematic elevation which shows the other aspect of the methane fermenter used for a hydrous waste processing method, (B) is the BB sectional drawing of (A). (A) is an elevation view of the plate-like contact floor element used in FIGS. 2 and 3, and (B) is a view taken along the line B-B of the contact floor element. It is a perspective view which shows an example of the flat net tube used for FIG. It is a perspective view which shows an example of the flat reticulated cylinder used as the component of the support body which carries | supports sulfur oxidation bacteria.

  Hereinafter, the processing method of the methane fermentation apparatus and the water-containing organic waste according to the present invention will be described together with actions based on the drawings.

  FIG. 1 is a flowchart of a method for treating hydrous organic waste 32 in one embodiment.

  The water-containing organic waste 32 removes foreign matters (such as inorganic substances) as a pretreatment. When the water-containing organic waste is liquid or slurry, it is used as the fermentation stock solution 7 as it is. When it is solid, it is used as the fermentation stock solution 7 as a slurry with the intermediate pulverizer 33 while water is poured as appropriate. Here, the pulverized particle size is 5 mm or less, desirably 3 mm or less, and more desirably 2 mm or less. This is because the fermentation stock solution 7 can be easily supplied to the methane fermentation tank 1 of the methane fermentation apparatus, and the fermentation decomposition can be promoted during the methane fermentation.

  Here, as the water-containing organic waste as a fermentation stock solution, those mentioned in the above-mentioned technical field can be used.

  Usually, the fermentation stock solution 7 which is a liquid or a slurry is stored in the stock solution storage tank 35, connected to the bottom outlet 37 of the stock solution storage tank 35, and connected to the bottom outlet 37 of the stock solution via a stock solution supply pipe 38 provided with a supply pump 36. Methane fermenter (hereinafter simply referred to as “fermentor”) 1. The stock solution supply amount to the methane fermentation tank 1 is controlled by a liquid flow meter 30 and a flow control valve 31 provided in the supply pipe 38.

  When the hydrated organic waste 32 contains livestock manure, etc., a sanitary treatment tank (not shown) is provided between the supply pump 36 of the stock solution supply pipe 38 of the stock solution storage tank 35 and the stock solution supply port 39 of the methane fermentation tank 1. It is desirable to disinfect and inactivate by heat treatment (for example, 70 to 72 ° C. × 1 h). Thereby, it becomes easy to make the compost (compost) 40 the direct liquid fertilization of the digested liquid and the sedimentation sludge 61 generated in the settling tank 51.

  And the methane fermentation apparatus of this embodiment is the fermenter 1 which carries out the anaerobic fermentation (methane fermentation) of the fermentation undiluted solution 7 from the water-containing organic waste 32, and the biodesulfurization tower 17 which performs the desulfurization of the biogas from the fermenter 1. And the gas holder 10 which stores the biogas after desulfurization is provided.

  Here, a primary gas pipe is provided between the gas outlet 15 provided at the top of the fermenter 1 and the gas inlet 18 provided on the bottom side surface of the biological desulfurization tower 17 (the height just below the microorganism carrier 19). 16 is connected. Further, the overflow inlet 41 of the fermenter 1 and the liquid inlet 56 formed on the side surface of the liquid reservoir 20 on the bottom side of the biological desulfurization tower 17 are connected by a digestive fluid transfer pipe 42. A gas outlet 28 provided on the upper end side of the biological desulfurization tower 17 of the microorganism carrier 19 and a bottom inlet (not shown) of the gas holder 10 are connected by a secondary gas pipe 16A. Further, a gas reflux pipe 12 is connected to the bottom reflux port (not shown) of the gas holder 10.

In addition, when the biogas produced by methane fermentation and the digestion liquid do not substantially contain H ₂ S and desulfurization is not performed, the biogas 11 may be directly introduced into the gas holder 10 without passing through the desulfurization tower 17. it can.

  As shown in FIG. 2, the fermenter 1 is usually in a bowl shape. It is because it becomes easy to perform discharge introduction of the biogas from the fermenter 1 to the gas holder 10 without using a gas transporter.

  Although the cross section of the fermenter 1 is circular in the illustrated example, it is arbitrary such as an ellipse, a rectangle, or a polygon. The ratio of the diameter (one side) to the height is preferably about 1: 1 to 1: 5. The material of the fermenter 1 is arbitrary, such as the product made from a steel plate, resin, and concrete.

  In addition, although not shown in figure, the fermenter 1 is equipped with the heat | fever means outside or inside while being coat | covered with the heat insulating material for heat insulation thru | or warming. Examples of the heating means include an electric heater, steam direct injection, and a jacket structure (hot water or steam). And in these heating means, the temperature in a tank is controlled to 30-40 degreeC, for example in the case of medium temperature fermentation, and 50-60 degreeC in the case of high temperature fermentation, respectively.

  The fermenter 1 includes a vertical circulation partition wall 2, a contact bed 4 filled in at least one of the inside and the outside of the circulation partition wall 2, and a circulation pipe 8 that circulates a fermentation stock solution supplied to the fermenter 1. It has.

  In the present embodiment shown in FIG. 2, the circulation partition wall is formed by an upflow pipe (draft tube) 2. The contact bed 64 is formed by filling the outside of the upflow pipe 2. The contact bed 64 is not particularly limited as long as it can support methane bacteria, and is not particularly limited, but is a plate-like contact bed element 65 proposed in Japanese Patent Publication No. 6-34997. It is desirable to form (refer FIG. 4).

  In the illustrated example, the contact floor 64 is a pair of contacts composed of large and small ring bodies in which a plurality of plate-like contact floor elements 65 are attached to the upper part of the inner wall of the fermenter 1 and have notches at predetermined pitches radially. Radially suspended and held on the floor frames 1a and 1b. As shown in FIG. 4, the contact floor element 65 has a supporting end in which an attachment member 67 and a weight 68 are attached to the upper and lower ends of a plurality of flat mesh tubes 66, respectively, and the upper and lower ends of the flat mesh tube 66 are closed. , The free end. As shown in FIG. 5, the flat net tube 66 has a shape formed by crushing the net tube almost completely.

  When the structure of the contact floor 64 is formed of the plate-shaped contact floor element 65 in which a large number of flat net tubes are juxtaposed and connected at least at the upper end as described above, However, it is peeled off moderately, and no clogging due to the generated flocs occurs, and the contact area with the fermentation stock solution is stabilized. From this point, the methane production efficiency is improved.

  Here, the inner diameter of the upflow pipe 2 is reduced to make it easy to generate a swirling flow. However, even if the inner diameter of the upflow pipe 2 is increased to form a contact bed inside the upflow pipe 2. Good. In this case, the air lift action is weakened and the stirring effect of the swirling flow 3 may be reduced.

  The first circulation pipe 8 includes a circulation pump 6 and a first suction injector (ejector) 9 in the circulation direction. The base of the circulation pipe 8 is connected to the suction port 5 formed at the bottom of the fermenter 1, and the tip is connected to the injection pipe 14. A second fluid inlet 13 is connected to the first suction injector 9 through a gas holder 10 and a gas recirculation pipe 12. The gas flow rate is controlled by a gas flow meter 30 </ b> A and a control valve 31 attached to the gas recirculation pipe 12 from the gas holder 10.

  Further, the injection port 14a of the injection pipe 14 is arranged so as to face the lower opening of the upflow pipe 2 (the lower opening inside the circulation partition wall).

And the swirling flow 3 which goes to the inner side from the outer side of the upflow pipe (circulation partition wall) 2 generate | occur | produces by injecting the to-be-processed liquid 7A in which biogas was sucked and mixed from the injection port 14a. Due to the action of both the jet effect and the convection circulation effect by the air lift, the treatment liquid 7 in the tank becomes droplets and repeatedly contacts the contact bed 4 many times to activate the methane bacteria. The fermentation treatment of the treatment liquid 7A is promoted. Thus, the organic matter in the liquid 7A to be treated is decomposed into lower fatty acids by acid producing bacteria and further decomposed by gas producing bacteria (methane bacteria) to produce biogas such as CH ₄ and CO ₂ . In the case where the organic matter contained sulfur-containing amino acids (cysteine, etc.), H ₂ S is also produced. For this reason, sulfur components are contained in both biogas and digested liquid (treated liquid), and it is necessary to perform a desulfurization process.

  In addition, although the circulation flow rate in the fermenter 1 is based on the magnitude | size of the fermenter 1, the flow rate which can be 0.2-1 rotation / h is desirable. Therefore, in the case of a large apparatus, the number of circulation pumps 6 and first suction injectors 9 may be increased. In addition, the biogas suction amount is added to the discharge amount of the circulation pump 6 to reduce the specific gravity of the circulating mixed fluid and increase the flow rate of the circulating jet flow. Therefore, a swirling flow is generated by a relatively small output circulating pump. Can do.

  The scum (floating floc) and digestive liquid (fermented liquid) 7A generated by the above methane fermentation are refined without the scum-containing digested liquid 7A being unevenly retained by the jet stirring action of the swirling flow 3 in the tank. The aggregate floc is not generated. Therefore, almost no mud is generated at the bottom of the fermenter 1, and no clogging occurs in the overflow port (transfer port) 41 or the digestive fluid transfer pipe 42.

  And the biogas produced | generated with the fermenter 1 is discharged | emitted from the gas outlet 15 of the fermenter 1, and is transferred to the biodesulfurization tower 17 via the primary gas piping 16. FIG. The treated liquid (digested liquid) 7A is also transferred from the overflow port 41 to the biological desulfurization tower 17 through the digested liquid transfer pipe. Here, biogas flows from the fermenter 1 into the gas inlet 18 of the biological desulfurization tower 17 with a differential pressure. Moreover, the digested liquid 7A flows from the fermenter 1 into the liquid storage section 20 of the biological desulfurization tower 17 by a drop.

  The biological desulfurization tower 17 is packed with a microbial carrier 19 on which sulfur-oxidizing bacteria are supported.

  The microorganism carrier 19 is optional such as a sponge body, Raschig ring, or a deodorizing resin alone. In particular, a contact floor element 65 (see FIG. 4) formed by a flat net tube 66 as shown in FIG. 5 proposed in the above-mentioned Japanese Patent Publication No. 6-34997, or a diagram proposed in Japanese Patent No. 3170636. It is desirable to form a contact bed by filling countless flat mesh-like cylinders 70 shown in Fig. 6 in the same manner as Raschig rings. In the latter case, the flatness changes when swirling and floating, and in the former case, the flat mesh tube swings independently, which makes it difficult for the microorganism carrier 19 to be blocked.

  And the liquid storage part 20 is provided below the microorganism carrier 19, and the shower pipe 27 is provided above the same, respectively. Between the suction port 23 at the bottom of the liquid reservoir 20 and the digestive fluid discharge port 23 </ b> A of the shower pipe 27, a second circulation pipe 24 including a circulation pump 22 is disposed. The circulation pipe 24 includes a circulation pump 22 and a second suction injector (ejector) in the circulation direction. A gas introduction port 18 is formed at a height position directly below the microbial carrier so that biogas can be introduced.

  Furthermore, a second suction injector 25 for sucking and mixing air into the circulating fluid (digestion fluid) is provided on the discharge side of the circulation pipe 24. The air suction pipe 26 of the second suction injector 25 includes an air flow meter 30B and a flow rate control valve 31, and can control the amount of suction air. Note that the amount of suction air required by the sulfur-oxidizing bacteria is 3 to 5% of the generated gas.

  When the circulation pump 22 is operated, the circulating fluid (digested fluid) in which air is sucked and mixed by the second suction injector 25 is ejected from the shower pipe 27 in the form of droplets. As a result, the biogas 11 that has flowed into the lower side of the microorganism carrier 19 from the fermenter 1 comes into countercurrent contact with the digested liquid at the site of the microorganism carrier 19.

Then, the sulfur-oxidizing bacteria carried on the microorganism carrier 19 are oxidized and activated by the air in the spray solution, and H ₂ S is efficiently oxidized to sulfuric acid (H ₂ SO ₄ ). In this way, the biogas and digestive fluid from the fermenter 1 are desulfurized.

Here, the reason why the digestive liquid is also desulfurized is that, as will be described later, H ₂ S is 2.3 volumes per volume of water, and it is considered that H ₂ S is also dissolved in the digestive liquid. When H ₂ S in the digestive liquid is not substantially contained, the circulating liquid directly uses city water (tap water), or the digested liquid is processed in a biological treatment tank, a sedimentation tank or the like as described later. Things may be recovered and reused. A purification treatment liquid described later may be used for reflux. The latter case is desirable because the amount of waste water can be reduced.

  The solubility of hydrogen sulfide and carbon dioxide in water is 2.3 volumes (25 ° C) and about 1 volume (room temperature and normal pressure) for 1 volume of water, respectively (Oki et al., “Chemical Dictionary”, Tokyo Chemical Dojin, (See 1994). In contrast, methane is almost insoluble in water. For this reason, by bringing biogas into counter-current contact with water, hydrogen sulfide is oxidized by sulfur-oxidizing bacteria while being absorbed in water, and carbon dioxide gas is dissolved and removed. As a result, it can be expected that the methane ratio of biogas increases and the quality of biogas is improved.

Furthermore, when hydrated organic waste contains a large amount of protein such as livestock manure during methane fermentation, that is, when the C / N ratio is low, the fermentation stock solution is too low (C / N ratio = less than 10). An organic acid ammonium is formed, and decomposition of the decomposed organic acid into CH ₄ and CO ₂ is inhibited. For this reason, it is desirable to remove ammonia in biogas and digestive fluid. In the present embodiment, ammonia is introduced into the biological desulfurization tower 17 and reacts with sulfuric acid generated in the biological desulfurization tower 17 to become neutral stable ammonium sulfate. Ammonia reacts with hydrogen sulfide to produce unstable ammonium sulfide (NH ₄ HS · NH ₃ ) that is easily tolerated and alkaline in water, but ammonium sulfide is introduced into the biological desulfurization tower 17 to produce sulfuric acid. To ammonium sulfate as well. For this reason, ammonia hardly inhibits methane fermentation and biological purification in the biological treatment tank 43 described later.

  The desulfurized biogas 11 is introduced into the gas holder 10. The internal pressure of the water-containing gas holder 10 is about 2 to 3 kPa (200 to 300 mmAq) in terms of gauge pressure. Moreover, the biogas stored in the gas holder 10 is used as the recovered gas 59, purified and sold to city gas or the like. Examples of the purification method include a conventional membrane separation method, an adsorption method, a chemical solution washing method, and a high-pressure washing method.

  On the other hand, the desulfurized digestive liquid is introduced from the overflow port 21 of the biological desulfurization tower 17 to the liquid inlet 44 on the bottom side of the aerobic biological treatment tank 43 through the desulfurization liquid transfer pipe 42A.

  The biological treatment tank 43 includes a vertical baffle plate (baffle) 46 for generating a swirl flow 45, and an aeration tube (aeration tube) 47 is arranged on one side thereof, and a contact bed 64 carrying oxidized bacteria on the other side. It is arranged. Air is blown from the diffuser tube 47 by a blower 48, and contact oxidation is performed by aeration. Here, as the contact floor 64, the one used in the fermenter 1 can be used.

  A liquid dropping pipe 50 is provided between the overflow port 49 provided in the upper part of the aerobic organism treatment tank 43 and the center well 52 of the settling tank 51, and the floc-containing treatment is performed from the aerobic organism treatment tank 43. The spent liquid flows into the settling tank 51 to drop. In this embodiment, flocs generated by biological oxidation (activated sludge) treatment in the aerobic biological treatment tank 43 are transferred as a primary cleaning liquid from the overflow port 49 to the precipitation tank 51 before being coagulated and settled. Flock does not settle at the bottom of the aerobic organism treatment tank 43.

  The sedimentation tank 51 is provided with a cylindrical center well 52 in the upper central portion, and a donut-shaped overflow port 54 between the center well 52 and the tank inner wall. The cleaning solution from the overflow port 54 is drained from the drain pipe 55 to the waste water groove 58.

  FIG. 3 shows another embodiment of the fermenter.

  This fermenter 1A is divided into a plurality of (four in the illustrated example) baffle plates (circulation partition walls) 60 on the inner side of the inner peripheral wall of the tank and an outer side made of four split circular sections as well as the inner side of the square section. Has been. The inside of the square cross section is filled with the contact floor 4, and the injection pipe 14 is arranged so that the injection port faces each lower opening of the split circular section. Then, when the circulation pump 6 of the circulation pipe 8 is operated to circulate the treatment liquid 7A in the fermentation tank 1A, the treatment liquid 7A in which biogas is sucked and mixed from the first suction injector 9 The fuel is injected from the injection pipe 14 into the lower opening of the split circular section. Since other configurations are the same as those in FIG. 2, the same reference numerals are given and description thereof is omitted.

  This fermenter 1A has the following advantages and disadvantages as compared with the fermenter 1 described above.

    1) Advantage: It becomes easy to obtain many swirling flows.

    2) Cons: The cost of baffle plates increases.

  Next, the outline of the operation and effect in the above embodiment is summarized as follows.

  The problem with the conventional methane fermentation apparatus is that clogging is likely to occur in the methane fermentation tank, the delivery port, the transfer piping, etc., resulting in low biogas production efficiency. The methane fermentation apparatus of the present invention can solve these problems.

  The methane fermentation apparatus of the present embodiment circulates and injects a fermentation stock solution by a circulation pump, and at the same time sucks and mixes biogas into the circulation flow, thereby refining suspended solids in the fermentation stock solution and Is also suppressed. Furthermore, by mixing and injecting the fermentation stock solution with biogas, the fermentation stock solution becomes droplets, methane bacteria are activated, and methane production efficiency is improved.

  In addition, since the amount of circulating water is large, the circulating water is uniformly distributed to any contact bed. For this reason, the bed of methane bacteria is uniform, all the contact beds can contribute to the biogas, and the fermentation efficiency is improved.

Further, in the biological desulfurization tower, the digestion liquid containing H ₂ S is circulated by a circulation pump and the suction injector is operated, whereby the circulating liquid in which air is sucked and mixed and oxygen is substantially saturated is injected. Sprayed from the mouth onto the microbial carrier. For this reason, desulfurization is efficiently performed by the sulfur-oxidizing bacteria that have been deposited on the microorganism carrier 19.

Since the biological desulfurization tower in the present invention does not use iron oxide or the like, which is a desulfurization agent for dry desulfurization, it is not necessary to periodically replace or supplement the desulfurization agent. In biological desulfurization, only oxygen in the air is used for the oxidation of H ₂ S, so desulfurization can be continued at low cost.

  The digested liquid produced by methane fermentation is adequately water quality (for example, average COD of 120 mg / L for water pollution method effluent standard day) that can be discharged through the sedimentation tank 51 in the aerobic biological treatment tank 43 through the biological desulfurization tower. It can be purified to a much lower value (see Table 2).

In addition, when the water-containing organic waste contains amino acids, when ammonia generated by methane fermentation is generated and the pH is 8 or more, organic acid ammonium accumulates, and decomposition of lower fatty acids into CH ₄ and CO ₂ is inhibited. The

  For this reason, in the said embodiment, although neutralized with the sulfuric acid produced | generated by the oxidation reaction of a biological desulfurization tower, ammonia is removed, the following method is also possible.

  Although illustration is omitted, the ammonia in the digested liquid may be vaporized and diffused in an aeration turbine using the surface aeration immersion hearth water treatment device proposed in Japanese Patent No. 2564131 having the following configuration.

  "In a surface aeration immersion filter bed water treatment device used in the contact oxidation method in the fixed contact method, which is a kind of biological treatment method, the water wheel is fixed to the upper part of the treatment tank so that it can rotate horizontally, and the water scraping member of the water wheel From the lower part of the water tank to the lower part of the treatment tank, a circulation partition plate having a lower part opened across the entire width of the treatment tank is provided, and the water level is adjusted to a position where a part of the water scraping member of the water wheel is submerged. In addition, the rotation of the water turbine causes the circulation to occur at the boundary of the circulation partition plate, and an immersion filter bed is disposed on at least one side of the circulation partition plate, and the immersion filter bed has a flat mesh tube. It is characterized by being formed by arranging a plurality of plate-shaped filter bed elements as main elements side by side. "

  Further, in the aerobic biological treatment tank in FIG. 1, the aeration method is performed using a blower and an air diffuser, but ammonia can be volatilized and removed during the aeration. For aerobic microorganisms, ammonia is an inhibiting factor, but if a plurality of biological treatment tanks are provided and aeration treatment is performed in the first stage, ammonia can be volatilized and removed.

  By filling the biological treatment tank with the circulating contact bed, the amount of activated sludge (MLSS: Mixed Liquor Suspended Solid) in the biological treatment tank (aeration tank) is greatly increased, so that treated water that can be discharged can be obtained.

Although there are some changes depending on the type of water-containing organic waste, medium-temperature fermentation treatment (37-38 ° C) is performed at 400-1200 L / kg-vs (per 1 kg of organic raw materials) with a residence time of about 10-15 days in the methane fermenter. The amount of generated gas) is obtained. At that time, the ratio of methane gas to carbon dioxide gas is within the range of the former / the latter = 54/46 to 69/31. And the low calorific value of the obtained biogas is 21000-23000 kJ / m < ³ >.

  Each organic waste was treated using an apparatus (tank / tower) with the following specifications.

<Methane fermentation tank 1 (1 unit)>
-Tank dimensions: 800φ x 1400H
-Tank capacity: 500L
・ Contact floor capacity: 300L
・ Circulating pump (1 unit) ・ ・ ・ 32A × 40L / min × 10mH × 0.25kW
・ Suction injector (2 units) ・ ・ ・ 32A × 32A
・ Heating heater (1 unit) ... 1kw

<Biodesulfurization tower 17 (1 unit)>
・ Tower dimensions: 350φ x 1600H
・ Microbe carrier capacity: 350φ x 900H = 85L
・ Water tank capacity: 350φ × 400H = 38L
・ Circulating pump (1 unit) ... 25A x 30L / min x 10mH x 0.2kW
・ Suction injector (1 unit) ... 25A × 25A

<Aerobic organism treatment tank 43 (two tank type one)>
-Tank dimensions: W800 x L1200 x H1200
-Tank capacity: 400L x 2 tanks = 800L
・ Contact floor capacity: 250L x 2 tanks = 500L
・ Blower ・ ・ ・ 25A × 0.2m ³ /min×0.1kgf/cm ² × 0.4kW

<Precipitation tank 51 (1 unit)>
-Tank dimensions ... 800φ × 1200H

<Water-containing gas holder 10 (1 unit)>
・ Water tank dimensions: 600φ x 600H = 140L
・ Gas holder dimensions: 450φ × 800H = 125L
・ Gas gauge pressure: 2 to 3 kPa (200 to 300 mmAq)

<Intermediate crusher (single-axis rotary blade crusher) 33 (1 unit)>
・ Cylinder dimensions: 200φ x L300
・ Power: 2.2kW

<Stock solution storage tank 35 (1 unit)>
-Tank dimensions: W500 x L800 x H500 = 200L
・ Supply pump (1 unit) ・ ・ ・ 25A × 30L / min × 10mH × 0.2kW

  And each dining room garbage of the following characteristic was grind | pulverized, or each pig manure was made into the fermentation undiluted | stock solution as it was. These fermentation stock solutions were subjected to methane fermentation (medium temperature fermentation: about 35 ° C.) and a series of post-treatments under the conditions shown in Table 1. “COD (Chemical Oxygen Demand)” was measured according to the CR method of oxidizing with dichromic acid.

<Dining room garbage>
-Moisture content: 85%, COD: 200 g / kg, grinding size: about 2 mm.

<Pig manure>
-Moisture content: 90%, COD: 90 g / kg, without pulverization.

  Table 2 shows the measurement results for each COD of biogas production amount / composition and digestive fluid / purified water. From the results shown in Table 2, it was confirmed that biogas having a good composition was obtained, and purified water having a sufficiently low COD that could be discharged into a river was obtained.

DESCRIPTION OF SYMBOLS 1 ... (Methane) fermenter 6 ... Circulation pump 7 of methane fermenter ... Fermentation undiluted | stock solution (processed liquid)
7A ... Digestive liquid (processed liquid)
9 ... First suction injector 10 ... Water-containing gas holder (gas holder)
17 ... Biological desulfurization tower 19 ... Microorganism carrier 22 ... Desulfurization tower circulation pump 25 ... Second suction injector 27 ... Shower pipe 32 ... (water-containing) Organic waste 33 ... Intermediate crusher 35 ... Stock solution storage tank 43 ... Aerobic treatment tank 51 ... Precipitation tank 64 ... Contact bed

Claims (5)

A methane fermentation tank for anaerobic fermentation fermentation stock solution from water-containing organic waste, a desulfurization tower for performing desulfurization, and a gas holder for storing biogas from the methane fermentation tank without carried or desulfurization desulfurization in the desulfurization tower a methane fermentation apparatus Ru provided with,
The methane fermenter is
A vertical circulation partition wall, a contact bed filled in at least one of the inner and outer sides of the circulation partition wall, and a circulation pipe for circulating the liquid to be treated;
The circulation pipe includes a circulation pump and a suction injector in the circulation direction,
The suction injector is connected to the gas holder so as to be able to suck biogas, and
An injection pipe is connected to the front end side of the circulation pipe, and an injection port of the injection pipe is arranged so as to face a lower opening inside or outside the circulation partition wall,
By injecting the liquid to be treated biogas is aspirated mixture from the injection port state, and are not swirling flow across the swirling flow partition wall has to be generated,
The desulfurization tower is
A microbial carrier is filled at the middle height of the tower, a liquid reservoir is provided below the microbial carrier, and a shower pipe is provided above the microbial carrier.
A liquid recirculation pipe connected to the liquid storage part of the desulfurization tower and connected to the shower pipe at the front part;
The liquid circulation pipe includes a circulation pump and a suction injector in the circulation direction,
Biogas can be introduced at a height position directly below the microbial carrier,
The microbial carrier is formed of a filling material of a flat reticular cylindrical body made of a synthetic resin having flexibility that can change flatness by water pressure.
A methane fermentation apparatus characterized by that.   2. The methane fermentation apparatus according to claim 1, wherein the contact bed is formed of a plate-like contact bed element in which a large number of flat net tubes are juxtaposed and connected at least at the upper end so as to be capable of swinging. 3. The methane according to claim 1 , wherein the microbial carrier is formed of a packed body of plate-like contact bed elements in which a large number of flat mesh tubes are juxtaposed and connected at least at the upper end so as to be capable of being oscillated. Fermenter. The desulphurization tower according to any one of claims 1 to 3, wherein the desulfurization tower is further capable of introducing a digested liquid from a methane fermentation tank into a liquid storage section. In the case of hydrated organic waste, if it is liquid or slurry, or if it is solid or contains a solid that does not form a slurry, it is crushed with an intermediate pulverizer to produce biogas by methane fermentation as a fermentation stock solution A method for treating hydrous organic waste,
While performing the said methane fermentation using the methane fermentation apparatus of Claim 4 , it introduce | transduces into the aerobic biological treatment tank the desulfurized digested liquid which generate | occur | produces from the said desulfurization tower, and also discharge | releases to a river through a sedimentation tank A method for treating hydrous organic waste, characterized by purifying it to a possible contamination concentration.

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