JP5020520B2 - Manufacturing method of organic fertilizer - Google Patents

Description

  The present invention relates to a method for producing organic fertilizer, and in particular, sewer sludge, animal and vegetable residues, and waste wood are all waste materials that require final treatment as raw materials. A method for producing an organic fertilizer that exhibits a fertilizer effect is provided.

  There are many proposals about using fertilized compost as an effective microorganism group (useful bacteria) as a raw material to make organic fertilizer.

First, there is Patent Document 1 as an example of a primitive one. A continuous manufacturing process for compost that is fermented based on wood fragments obtained by processing waste materials and mixing them with domestic waste such as animal manure, activated sludge, sludge, sludge, and sugar beet waste has been proposed. .
This is primitive and valuable information, but it is not practical as it is, and many improved technologies are being proposed one after another.

  For example, in Patent Document 2, high-speed composting is performed by contacting ozone-containing gas in a fermentation process in order to shorten the time for complete ripe composting when the content of biological waste such as lipids and fibers increases. It has been shown that it can.

  Further, Patent Document 3 proposes a method for eliminating the off-flavors and odors from organic industrial waste and making the processed compost easily absorbed by plants in composting treatment of organic industrial waste. A compound containing Ca and a compound containing Mg are added to the treated waste at a predetermined weight ratio of 0.1 to 1.5%.

  These prior arts describe the term organic fertilizer, but the purpose is to reduce the volume and volume by treating the waste, and the social needs at that time were also there. It was far from organic fertilizer, but it was completely different in dimension.

  Therefore, the inventors of the present application have developed a technique for composting harmless organic matter and using it as an organic fertilizer, and filed a patent application first, and disclosed a specific practical technique as Patent Document 4.

  That is, after mixing sludge and approximately 1 to 3 cm square wood chips and spraying fermented bacteria mainly consisting of lactobacilli and yeast, the primary fermentation process for approximately 2 weeks, approximately 2 to 3 weeks The processing method of the sludge which performs the fermentation process which consists of the secondary fermentation process of this and a final fermentation process of about one week is disclosed, and the organic fertilizer of a specific component ratio is also shown.

  The inventors of the present application disclose detailed technical matters in Non-Patent Document 1. The composting technique of this paper is the prior application of the inventors of the present application disclosed in Patent Document 4.

  Patent Document 4 and Non-Patent Document 1 disclosed the most excellent sludge composting technology at that time. Currently, many compost plants are operating according to these disclosed techniques. Although it is a sufficient technique for mere weight reduction, it was not completed as an organic fertilizer manufacturing technique and was insufficient. In other words, when a commercial plant was put into operation and entered into the mass production stage, there were major problems in terms of reproducibility and yield.

  In other words, the quality of the obtained organic fertilizer varies widely, and good and defective products can be randomly produced for each batch. I had to do it.

When manufacturing industrial products, when it is not possible to discriminate between acceptable products and rejected products in the manufacturing process, the manufacturing technology is incomplete and immature, leaving significant issues to be solved. Therefore, the elucidation is essential. It goes without saying that even if the root cause is not clarified, it is sufficient as an industrial technique if a determination means is found.
JP 54-75363 A JP 7-126092 A JP-A-10-95687 JP 2000-169270 A "Sludge reduction and recycling by compost using wood chips and humus soil extracted microorganisms" Kokushikan University Institute of Science and Engineering Report No. 15 (2003) pages 34-49 "Small encyclopedia of wood," Wood Science Institute Kiso Association, Kodansha, pp. 37-38, 2001 “Organization of Organic Waste Resource Encyclopedia”, Organic Resources Recycling Promotion Conference, Agricultural Welfare Association, p.187, 1997 "Microbiology for environmental purification", Ryuichi Sudo, Kodansha, p.4, 1992 “Microbiology for environmental purification”, Ryuichi Sudo, Kodansha, p. 7, 1992 "Introduction to Water Treatment Biotechnology" by Ryuichi Sudo and Kohei Inamori, Industrial Water Research Committee, p.94, 1994 “Microbial engineering” Kazuo Nagai, Shigeru Nakamori, Tetsuo Toraya, Hiroaki Horikoshi, Kodansha, p.40, 1996 “Iwanami Biology Encyclopedia” Iwanami Shoten, p.34, 1974

  This invention is made | formed in view of said situation, and this invention aims at providing the manufacturing method of the organic fertilizer which can suppress the dispersion | variation in quality and can manufacture an organic fertilizer.

  The method for producing an organic fertilizer of the present invention is a method for producing an organic fertilizer by fermenting an organic fertilizer raw material with a microorganism to obtain an organic fertilizer, the step of mixing the wood chip including a return chip and the organic fertilizer raw material, Observing the cross section of the deposit in the passage portion of the sieve, the step of fermenting the mixture of the organic fertilizer raw material and the wood chip at a macro level, the step of sieving the mixture and separating the mixture into the return chip and the passage portion And determining the progress of the fermentation, and fermenting the fluid passing part at a micro level and aging to make an organic fertilizer.

  The method for producing an organic fertilizer of the present invention is a method for producing an organic fertilizer by fermenting an organic fertilizer raw material with a microorganism to make the organic fertilizer, and first, the wood chip including the return chip and the organic fertilizer raw material are mixed, The resulting mixture is fermented at the macro level. Next, the mixture is sieved and sorted into a return chip and a sieve passage portion, and the progress of fermentation is determined by observing the cross section of the deposit in the sieve passage portion. Further, the passage part of the sieve is fermented and matured at a micro level to obtain an organic fertilizer.

  In the method for producing an organic fertilizer of the present invention, preferably, the organic fertilizer raw material includes sewage sludge and / or animal and vegetable residues.

  In the method for producing an organic fertilizer according to the present invention, preferably, the step of fermenting at the macro level includes a primary fermentation step, a secondary fermentation step, and a finish fermentation step, and the mixture is aerated and turned over. To perform fermentation at the macro level.

In the method for producing an organic fertilizer according to the present invention, preferably, in the step of fermenting at the micro level, the proliferation activity of microorganisms remaining in the sieve passage portion by promoting the contact between the sieve passage portion and the atmosphere. Promote.
More preferably, in the step of fermenting at the micro level, the flue passage portion is spread on a sheet and cut back, and / or the fluid passage portion is stirred in a container. Promote contact with the atmosphere.

In the method for producing the organic fertilizer according to the present invention, preferably, as a step of confirming the progress of the fermentation, the pile of the sediment passing through the sieve is cut and the cross section is observed, and the inside of the mountain becomes white. The progress of the fermentation is determined by confirming that the portion being formed is formed.
Alternatively, preferably, as the step of confirming the progress of the fermentation, a part of the mixture during the finish fermentation is extracted, and the sieving step separates the mixture into the return chip and the sieve passage portion, and the obtained sieve passage portion. A pile of deposits is formed, the mountain is cut and a cross section is observed, and the progress of fermentation is determined based on the formation of a white portion inside the mountain and the calorific value from the mountain.

  The method for producing an organic fertilizer of the present invention can produce an organic fertilizer while suppressing the variation in quality by observing the cross section of the deposit at the sieve passing portion and determining the progress of fermentation.

  Hereinafter, an embodiment of a method for producing an organic fertilizer according to the present invention by fermenting an organic fertilizer raw material with microorganisms to obtain an organic fertilizer will be described with reference to the drawings.

The organic fertilizer manufacturing method according to the present embodiment provides a truly useful and excellent organic fertilizer.
Chemical fertilizers that have been effective in expanding the amount of harvested crops due to the abuse of fertilizers by chemical synthesis are now manifesting various harmful effects such as soil contamination and the death of soil bacteria.
The method for producing an organic fertilizer according to the present embodiment provides an organic fertilizer that is effective for assisting the original ability of a plant that self-grows by skillfully utilizing a soil environment or an atmospheric environment. Ideally, all the constituent elements of the applied fertilizer are absorbed by the growing plant and do not remain in the soil or in the ground water (environmental water). On top of that, delicious crops have yields equal to or better than those using chemical fertilizers. Furthermore, the safe and secure method at the atomic level for both people and the global environment will be the fermentation method, but it is also essential for the microbial world to take care not to cause species disruption or disturbance. is there.

FIG. 1 is a flowchart showing steps of a method for producing an organic fertilizer according to the present embodiment.
Step S10 for mixing the wood chip including the return chip and the organic fertilizer raw material, Step S20 for fermenting the mixture of the organic fertilizer raw material and the wood chip at a macro level, and sieving the mixture to separate it into the return chip and the sieve passage portion. It has process S30, process S40 which judges the progress of fermentation by observing the section of the deposit of a passage part of a sieve, and fermenting and ripening a sieve part by a micro level, and making it an organic fertilizer.

  Preferably, the step S20 for fermenting at the macro level includes a primary fermentation step S21, a secondary fermentation step S22, and a finish fermentation step S23, and the mixture is aerated and turned over to perform fermentation at the macro level. To do.

Preferably, in step S50 of fermenting at a micro level, the contact between the sieve passage and the atmosphere is promoted to promote the growth activity of microorganisms remaining in the sieve passage.
Specifically, in the step of fermenting at the micro level, the sieve is expanded by spreading the sieve passage part on the sheet, and / or by putting the sieve passage part in a container and stirring, the sieve part and the atmosphere are mixed. Promote contact.

In the method for producing an organic fertilizer according to the present embodiment, as the step S40 for determining the progress of fermentation by observing the cross section of the mixture or the deposit in the sieve passage portion, for example, a white portion is formed inside the mountain. The progress of the fermentation is determined by confirming that it has been done.
Or, for example, as a process of confirming the progress of fermentation, a part of the mixture during the final fermentation is extracted and separated into a return chip and a sieve passing part by a sieving process, and a pile of deposits of the obtained sieve passing part is formed. Then, it is possible to determine the progress of fermentation based on the fact that a white portion is formed inside the mountain and the amount of heat generated from the mountain is observed by cutting the mountain and observing the cross section (S24).

In the method for producing an organic fertilizer of this embodiment, preferably, the fertilizer raw material includes sewage sludge and / or animal and plant residues.
As the main raw material sewage sludge, sludge from a combined treatment tank that is widely installed in large-scale sewage treatment plants and households, that is, sewage sludge derived from humans is used. Sewage sludge derived from the excrement of humans (humans and humans) is currently the best from the viewpoint of safety, security, environmental impact, etc. as a fertilizer raw material, and its nutritional value is high, so as a fertilizer raw material Is optimal. In addition, effective use and recycling of increasing sewage sludge has become a major social issue, and it is a biomass raw material that cannot be overlooked from that viewpoint.

  Do not use sludge derived from animals other than humans unless safety has been confirmed. This is because sewage sludge derived from cattle, pigs, horses, and other animals has a high risk of containing antibiotics, heavy metals, agricultural chemicals, etc. contained in feeds or drugs. On the other hand, human excreta has few harmful substances such as hormones, antibiotics and heavy metals, and is rich in nutritional components and is highly safe overall. It becomes an effective fertilizer that is safe and secure.

  Animal and vegetable residues are also essential raw materials from the viewpoint of organic waste that is to be effectively processed and discharged in large quantities, and nutritional component adjustment. Also in this respect, from the viewpoint of safety, security, and environment, a residue generated in the processing place of what is eaten or drunk by humans is preferable. Specifically, it includes residues associated with food processing such as wastewater treatment sludge and meat in food processing factories such as ham factories, and tea leaf residues of green tea for PET bottles. In other words, it is the residue of what human beings eat and drink, the residue in the process of manufacturing it, and the residue of its raw materials. In the course of the biological cycle, there is a concern that accumulation and concentration will increase even with trace amounts of components, so those that have been administered pesticides, antibiotics, hormones, etc. should be thoroughly eliminated.

  Wood chips (wood chips) used in the method for producing organic fertilizer of this embodiment are not wood chips cut with a cutter or saw, but are wood chips made by physically crushing with a crusher or the like. It is important that the fine pores (honeycomb tube-like pores described later) are not blocked, and this is the first requirement for wood chips.

The second requirement for wood chips is that the lignin component is as low as possible. For this reason, waste wood such as old wood or pillars accompanying the dismantling of a house, which is more than 5 years after logging, preferably 20 years or more, is optimal. Of course, such timber can be used if lignin is not included or reduced significantly by any means.
Since the size and shape of the wood chip are not essential conditions, they may be appropriately selected from the relationship with the machine to be used and the processing space. As will be described in detail later, the role of the wood chip in the present invention is as follows: (1) where microorganisms reside, (2) ensuring air permeability in the fermentation process, (3) reducing the amount of water contained in the raw material, (4 4) The material of the return tip.

  As the last part of the raw material, the return chip (planted wood chips) will be described. Wood chips containing various types of microorganisms are sieved after the compost fermentation finishing stage, and chips that do not pass through the sieve are returned to the initial raw material mixing section. This is the return chip. A large number of bacteria suitable for compost survive on this return chip, and bacteria suitable for the newly introduced compost material will be seeded. Further, the return chip sequentially passes through the fermentation process in an extruded flow together with the compost material, and bacteria suitable for the fermentation state are activated at each stage. For this reason, not only fermentation starts up smoothly, but also the generation of malodor is reduced during the process.

  Since the method for producing organic fertilizer according to the present embodiment is composting by microbial fermentation, considerations specific to microbial fermentation are indispensable. That is, an excellent fermented product cannot be made until the many microbial environments involved in the fermentation process are stabilized. In other words, as many operations are repeated, the walls and ceilings of processing spaces such as factories and even mechanical devices such as excavator loaders and agitation devices are optimized to ensure a stable microbial environment. Only then has an excellent product been made. It can be thought of in the same way as the effects of microorganisms living in sake breweries in sake brewing. The return chip is a chip that contributes to excellent composting by being repeatedly circulated through many operations.

  Although it is customary to differ for every plant, it is preferable to use the return chip of the plant implemented by the method of the present application for another new plant because time is shortened. However, since different aspects such as temperature, humidity, and indigenous microbial species can be different, it is best to use a return chip made in that plant.

  As is clear from the above description, the organic fertilizer manufacturing method of the present embodiment does not spray or administer any special microorganisms from the raw material stage. Rather, it is not preferable because there is even a concern that a stable microbial environment suitable for the situation is prepared.

Next, the above process will be described.
Regarding the blending / mixing ratio of raw materials, the mixing step S10, the macro-level fermentation step S20, and the sieving step S30, the contents described in our earlier patent (Patent Document 4) and paper (Non-Patent Document 1) Therefore, detailed description is omitted here.

  In the manufacturing method of the organic fertilizer of this embodiment, the fermentation process at a macro level corresponds to what is described as fermentation or a fermentation process in Patent Document 4 and Non-Patent Document 1. That is, it is a step of fermenting a sludge mixture containing coarse and irregularly shaped wood chips extending to several tens of centimeters. In this embodiment, in order to distinguish from the below-mentioned micro level fermentation process, it describes with this name.

  The macro-level fermentation process S20 requires aeration (fan) and turn-over (stirring, replacing), which is necessary for the gradual fermentation specific to the microbial reaction. In this embodiment, it is preferable to divide into three stages (namely, primary fermentation process S21, secondary fermentation process S22, and finish fermentation process S23).

Here, primary fermentation process S21 is a process aiming at proliferation of fermentation bacteria, elimination of sludge odor, reduction of water content of sludge, and decomposition of relatively large solid matter in sludge.
In the secondary fermentation step S22, the water content is reduced to 40% to 50% in the primary fermentation step S21, and the sludge refined compared to before the fermentation step is further advanced in fermentation to the carbon component in the sludge. This is a step of improving the degree of decomposition and reducing the water content to 35% to 45%.
Finishing fermentation process S23 completes decomposition | disassembly of the carbon component in the sludge by fermentation about the sludge from which moisture content fell to about 35%-45% in secondary fermentation process S22, and the moisture content of sludge is 30%- It is a process aimed at reducing to 40%.

In the sieving step S30, the material is separated into a coarse product that does not pass through the sieve (return chip) and a granular material part that passes through the sieve (fluid passing part). The sieve passage part may contain a powdery substance in addition to the granular part.
Normally, the granular material passing through the sieve accumulates and rises like a mountain. It may be placed directly in the container to facilitate later handling and transport operations. In any case, it has a certain thickness (depth).
Here, in each fermentation process, a part of the wood chip is chipped or collapsed to become a small piece of wood, but by adjusting the size of the eyes of the sieve used in the sieving step S30, The mixing ratio can be adjusted. Increasing the size of the sieve will increase the mixing rate of the pieces of wood, and decreasing the size of the opening will reduce the rate of mixing of the pieces of wood.
When mixed with organic fertilizers, the above-mentioned pieces of wood have a function of helping the plants to grow greatly by assisting the independence of the plants when the roots are stretched for some plants. In addition, as an organic fertilizer for growing green on a golf course, it is preferable that wood chips are excluded.
For this reason, depending on what kind of plant is used, the size of the eyes of the sieve can be changed to change the mixing rate of the pieces of wood.

  In the present embodiment, the fermented state is confirmed by exposing the cross section in the thickness direction in the mountain-shaped deposit of the granular material portion (fluid passage portion) formed as described above (S40). For example, it is a proof that excellent composting has been performed if the mountain-shaped deposit is broken in the depth direction to expose the cross section and the inner layer portion appears white. If the inner layer portion is the same as the surface layer portion and does not look white, a defective product will be made, so it will not be a true organic fertilizer as used herein. This is what we have found as a result of repeated operations. Until this confirmation process was adopted, there was a random variation in the final product, which was unlikely to be a constant product, but this problem was resolved after obtaining this knowledge.

Although the case where the fermentation confirmation process S40 is performed after the sieving process S30 has been described above, it is also preferable to perform the fermentation confirmation process S24 before the sieving process.
That is, a part of the fermented product is extracted from the third stage fermentation process S23 of the macro-level fermentation process S20, sieved and sorted into a return chip and a sieve passage part, and the resulting sieve part is deposited. Form a mountain of objects, cut the mountain, observe the cross-section, and due to the formation of a white part inside the mountain and the amount of heat generated from the mountain, it is not the surface layer of the pile of deposits but the inner layer part After confirming that the fermentation is performed, the whole amount may be transferred after the sieving step.

Academic clarification regarding this phenomenon is a future subject, but the inventors of the present application presume as follows. That is, at least actinomycetes and nitrifying bacteria play a major role in the fermentation process of the method for producing organic fertilizer of the present embodiment.
Actinomycetes have a fast growth rate, and vigorously grow from the initial stage of fermentation, and white filamentous cells can be visually observed from the inside to the surface of the compost material throughout the entire fermentation process.
On the other hand, nitrifying bacteria having a slow growth rate have never been confirmed so far to confirm that they have sufficiently grown and contributed to fermentation. Nitrifying bacteria are small in number compared to actinomycetes, and it is impossible at the stage where actinomycetes are active. Granules that have passed through the sieve obtained in the sieving process after the role of actinomycetes is almost over (fluid passing part) It is optimal to make a determination in).

In this granule, the number of actinomycetes is reduced, and the nitrifying bacteria having a slow growth rate still have the ability to grow and still exist as main microorganisms. The white state visible in the cross-sectional layer of the granular deposit is the presence of residual nitrifying bacteria, in other words, in the previous fermentation process, not only fast-growing actinomycetes but also slow-growing nitrifying bacteria worked well. I think it is a barometer to show things. It also confirms that the nitrifying bacteria have been firmly picked up on the return tip.
Detailed discussion on the action effect of nitrifying bacteria will be described later.

In the manufacturing method of the organic fertilizer of this embodiment, fermentation process S50 in a micro level is performed after said process.
As described above, since at least nitrifying bacteria having a slow growth rate are still capable of growing in the granules passing through the sieve, the fermentation is not completely completed. It is considered that microorganisms other than nitrifying bacteria still remain. Above all, since the powder or granules passing through the sieve are homogeneous and free of coarse products, microorganisms, fine wood chips, degraded sludge particles, etc. are intimately mixed, so fermentation at the micro level is performed. It is in the environment to be called.

Therefore, this process is indispensable as a final finishing step for producing a fermented product. In the present embodiment, the action of microorganisms in this environment is equivalent to ripening without stopping in the atmosphere, that is, allowing the proliferation activity of nitrifying bacteria to be sufficiently performed.
Specifically, the process is completed in a state where no heat is generated by performing a method such as a method of sometimes stirring in a predetermined container in the atmosphere or a method of depositing on a sheet with a certain thickness. Since fever is a sign that microorganisms are actively proliferating, this process cannot be continued until the fever ceases.
In the step of fermenting at the micro level, it is also possible to adjust the water content by evaporating water in the atmosphere.

FIG. 2 is a schematic configuration diagram of a composting facility for carrying out the organic fertilizer manufacturing method according to the present embodiment.
The processing capacity of this composting facility is, for example, 165 t / day.
This compost facility has, for example, a mixing yard 20, a primary fermenter 30, a secondary fermenter 40, a finish fermenter 50, and a sieving and micro level fermenter 60.

  The mixing yard 20 is provided with an unused chip storage area 21 adjacent thereto, and a return chip storage area 22 in which a return chip returned by circulating the fermentation process is placed in the mixing yard. In the yard 20, the organic fertilizer raw material used for the composting and the wood chips including the return chips are mixed.

The 1st fermenter 30 is comprised from the fermenters 31-38 of 8 rooms on both sides of a channel | path, and the primary fermentation of said compost raw material, a wood chip, and the mixture of microorganisms is performed.
For example, the compost material is aerated in the fermenter only in the daytime, and is processed under conditions that do not aerate at night (from 4:30 in the evening to 8 am) and on holidays.

  The 2nd fermentation tank 40 is comprised from the fermenters 41-44 of 4 rooms on both sides of a channel | path, and secondary fermentation is performed similarly to said primary fermentation.

The finishing fermenter 50 performs a turnover process necessary for the fermentation state up to the secondary fermentation. Thus, macro-level fermentation is performed.
After the secondary fermentation is completed, the sieving and transported to the micro-level fermenter 60.

In the sieving and micro level fermenter 60, the returned chips are sorted out by sieving from the mixture in which the macro level fermentation has been performed, and the fermentation check process is performed as described above for the obtained sieve passage part. Fermented with.
When the fermentation process at the micro level is completed, the product is packed into a product.

FIG. 3 is a schematic cross-sectional view of a mountain-shaped deposit in the step of exposing the thickness direction cross-section and confirming the fermentation state in the mountain-shaped deposit of the granular material portion (fluid passage portion) after the sieving step. FIG.
When fermentation is sufficiently progressing, a whitish portion 71 is observed in an inner layer portion of the cross section of the central portion of the mountain deposit 70, for example, a portion on the inner side of about 2 cm from the surface layer portion. When observed in this way, it can be subsequently fermented at a micro level and shipped as a product.

  According to the method for producing organic fertilizer according to the present embodiment described above, by observing the cross section of the sediment passing through the sieve passing portion and determining the progress of fermentation, the organic fertilizer is suppressed by suppressing variation in quality. Can be manufactured.

  Hereinafter, findings by the present inventors will be described.

1. The role of wood chips The structure of wood chips consists of honeycomb tube-shaped pores that are long, and in conifers such as cedar and pine, the temporary conduit is a fibrous cell with a diameter of several tens of micrometers and a length of several centimeters. It is known (see Non-Patent Document 2). Moreover, it has been clarified that the cedar chip has a honeycomb structure and thus is suitable as a microorganism's house and is an excellent carrier in high-temperature aerobic treatment (see Non-Patent Document 3).
Wood chips have fine honeycomb-shaped tubes that are not preyed by large protozoa that cannot enter here, and bacteria that have a slow growth rate using nutrients soaked around the tube as an activity source It is thought that the species can survive. FIG. 4 shows an electron micrograph of a cut surface of a new wood chip.

1.1 The role of wood chips as a microorganism entrepreneur As described above, wood chips are considered suitable as a microorganism entrepreneur. This is thought to be largely related to the size of the microorganisms in the compost sludge.
The large ones of bacteria reach 30 μm, while the small ones are 0.2 μm. Sulfur and iron bacteria are the largest bacteria. For cocci, there are many diameters of 0.5 to 1.0 [mu] m, and for bacilli, (0.5 to 1.0) * (1.0 to 2.0) [mu] m. Actinomycetes are bacteria that have a filamentous form and have been morphologically differentiated like a filamentous fungus. The width of the mycelium is about 0.3 to 1 μm (see Non-Patent Document 4).

The size of the protozoa is about 5 μm at the minimum, and the maximum is 3 mm. In general, most of them are around 50 to 100 μm (see Non-Patent Document 4).
Protozoa are divided into the following four classes (see Non-Patent Document 5).
(1) Flagellates: move with one or more flagella (2) Carnivores: move with pseudopods (3) Spores: have no motility, make spores and are parasitic (4 ) Ciliates: Exercise by cilia

Since the compost deposit is a mass of solid matter, it is expected that protozoa of the carnivorous worms survive in the compost.
Table 1 shows the size and length of protozoan cells generated by sewage treatment.

2. Nitrogen Circulation and Nitrification Bacteria 2.1 Nitrogen Circulation and Nitrification Nitrogen contained in organic substances changes through the following pathways as organic substances are decomposed by microorganisms.

Organic substance (organic nitrogen) → Ammonia → Nitrous acid → Nitric acid → Nitrogen gas
General bacteria Nitrite bacteria Nitric acid bacteria General bacteria

  The above reaction is represented by the chemical formula as follows.

[Chemical 1]
NH ₄ ⁺ + 3 / 2O ₂ → NO ₂ ⁻ + H ₂ O + 2H ⁺
NO ₂ ⁻ + 1 / 2O ₂ → NO ₃ ⁻

  Here, nitrite bacteria (genus Nitorosomonas) are bacteria that change ammonia into nitrite. On the other hand, nitric acid bacteria (genus Nitrobacter) are bacteria that change nitrous acid to nitric acid, and these two genera are collectively called nitrifying bacteria. Furthermore, the reaction (denitrification) in which nitrous acid and nitric acid are converted to nitrogen gas has the ability even in general bacteria, but among the denitrification bacteria, Pseudomomas denitrificans is said to have a high denitrification ability.

The specific growth rate of nitrifying bacteria is 0.21-1.08 day ^{−1 for} the genus Nitorosomonas and 0.28-1.44 day ⁻¹ for the genus Nitrobacter.
It is extremely small compared to 40-60 day ^-1 such as facultative anaerobes such as Escherichia coli and Proteus sp. (See Non-Patent Document 6). This indicates that the growth rate of nitrifying bacteria is extremely slow.
FIG. 5 shows an electron micrograph of bacteria attached to the return chip.

2.2 Wood chips and nitrifying bacteria Since nitrifying bacteria have a slow growth rate as described above, the nitrifying bacteria that were present in the imported material grow somewhat during compost fermentation, but the materials being fermented are extruded. Since it flows in a flow pattern, it will be discharged out of the system together with the finished product. For this reason, in the compost of the system in which the material to be carried is not seeded, the ammonia generated by the decomposition of organic nitrogen is diffused into the atmosphere with almost no nitrification.
In this composting method, chips that are physically crushed are used, not wood chips that have been cut with a cutter over 20 years after logging. As a result, as shown in FIG. 4, the opening of the honeycomb tube of the chip is not crushed, and bacteria can easily enter the tube. Bacteria that have entered the tube are not preyed because the protozoan body that eats them is large and cannot enter the tube. Considering this, nitrifying bacteria with a low specific growth rate (low growth rate) grow in the tube using ammonia that has soaked into the honeycomb tube as a growth substrate and actively oxidize ammonia to nitric acid. Can be considered.
FIG. 6 shows an electron micrograph of bacteria in the obtained organic fertilizer (finished product). This is the deposit after sieving.

3. Oxidizing organic substances in the circulation and sulfur bacteria 3.1 circulation sulfide sulfur of sulfur, particularly sulfur contained in the protein and fat, with the the decomposition of organic matter by microorganisms, S ^2-(sulfite, H ₂ S, etc.). This S ²⁻ changes to sulfate SO ₄ ²⁻ via SO ₃ ²⁻ by aerobic bacteria. When this change is expressed by a chemical formula, the following formula is obtained (see Non-Patent Document 7). In this reaction, sulfite (H ₂ S or the like) is changed to sulfate ion. In this reaction, hydrogen sulfide H ₂ S, mercaptan R-SH, and the like are changed to sulfuric acid, and the generation of malodor is reduced.

[Chemical 2]
S ²⁻ + 2O ₂ → SO ₄ ²⁻

3.2 Chips and sulfur bacteria Sulfur oxidizing bacteria include Thiobacillus, Thiomicrospira, Sulfolobus, and Thiotrix. Data on the specific growth rate of these bacteria has not been published. These bacteria are also estimated to have a slow growth rate. Thiotrix is a large filament, which forms sulfur particles in the cells due to the presence of hydrogen sulfide and acts as an energy source when there is no food supplement. The reaction at that time is probably the following formula (see Non-Patent Document 8). As described above, sulfur bacteria are large and are estimated to be about 30 μm.

[Chemical 3]
H ₂ S + 1 / 2O ₂ → H ₂ O + S
S + 3 / 2O ₂ + H ₂ O → H ₂ SO ₄

  It is presumed that sulfur bacteria also enter the honeycomb tube of the chip, are not preyed by protozoa, and change sulfides to sulfuric acid.

4). The effect of wood chips Wood chips with various types of microorganisms are put into a sieve after fermentation in the compost finishing stage, and chips that do not pass through the sieve are returned to the first mixing tank (return chips) and newly added. Mixed with the compost material carried in. Many bacteria suitable for compost survive on the return chip, and bacteria suitable for the newly introduced compost material will be seeded. Further, the return chip moves along with the compost material in the form of an extruded flow in the fermenter, and bacteria suitable for the fermentation state are activated at each stage. For this reason, not only fermentation starts up smoothly, but also the generation of malodor is reduced during the process.

  In addition, the wood chips can be stacked in a pyramid shape, and sludge enters the gaps between the chips, so that the sludge is not compacted and air permeability is improved. Further, it is considered that the chip has honeycomb-shaped pores, and air is released from the holes, improving air permeability. In addition, it helps to reduce the moisture content of the imported material.

Based on the above considerations, it seems that the important role and effect of the fermentation growth confirmation process of the present application will be highlighted.
In other words, it was a very coarse mixture of wood chips and sludge until the fermentation process, but in the sieving process, it became a “powdered or granular material” and a coarse product (the portion that did not pass through the sieve). To be separated. This “powder or granule” is made up of three main components: micro-sized microorganisms, fermentation objects (composts), and finely crushed wood chips. Since the various microorganisms involved in fermentation and their food (fermentation object) are rearranged in close proximity, it is thought that “fermentation at a microscopic level” will proceed again. At that time, nitrifying bacteria and sulfur bacteria having a slow growth rate are considered to be relatively active. In addition, it is considered that the growth of nitrifying bacteria and the like is not observed in the surface layer portion of the powdery or granular pile passing through the sieve because ammonia and the like easily escape into the atmosphere.

In the present application, it can be understood from the above consideration that a fermentation process at a micro level is indispensable.
After the sieving process, it can be said to be an essential process for performing “fermentation in a micro dimension”. In macro-level fermentation, micro-sized bacteria and protozoa are actively working on a mixture of coarse and irregularly shaped wood chips and wet sludge. This is because, from the viewpoint of microorganisms, the presence of wood chips that are huge in size is a distance obstacle to movement, and is considered to be an obstacle to the completion of homogeneous fermentation as a whole. It is necessary to remove this distance obstacle, achieve a homogeneous fermentation state, and use up the remaining growth potential of the microorganisms. It is understood that fermentation at the micro level is essential for producing an excellent fermented product.

Example 1 (sludge, meat factory residue)
As raw materials for organic fertilizer, 9 tons of sewage sludge (dehydrated) generated at a sewage treatment plant in Tochigi Prefecture and 1 ton of dehydrated sludge generated at a wastewater treatment facility at a food processing plant were used. The amount of wood chips and return chips, which are about twice as large, were stirred with an excavator loader. This mixing process was carried out in a large concrete container (width 5 m, depth 5 m, height 2 m, no ceiling, building with roof with exit open).

  The wood chip used here is obtained by cutting old wood that has been discarded from house demolition into a size of several centimeters to several tens of centimeters using a crusher. The return chip is a coarse product (wood is a main component) that has not passed through the sieving step in the processing step of the plant operated by the method of the present invention. As for the ratio of the return chip to the wood chip, 80% was the return chip and the remaining 20% was the wood chip.

  The macro-level fermentation process was performed in three stages for convenience. The space is the same size as the above mixing step, except that a lot of holes are made in the concrete floor, and the outside air can be sent (aeration) by operating an external compressor.

First, as a first fermentation process, the above mixture was piled up in a mountain shape for 2 weeks. During this time, aeration (air blowing) was performed every day for 7 hours. Stirring with the shovel loader and pile-up work were performed only once on the 7th day.
In the final stage of the primary fermentation, the temperature of the fermented processed product piled up in a mountain shape was 68 ° C., the pH was 7, and the water content was 55%.
On the 14th day, which is the final day of the primary fermentation, the entire fermented product was transferred to the secondary fermentation space with a shovel loader and piled up in a mountain shape.

The secondary fermentation space was similar in structure and size to the primary fermentation space. Here, fermentation treatment for 3 weeks was performed. As a general rule, aeration (air blowing) was carried out every day for 7 hours in the daytime, and turning-over and re-loading with an excavator loader were performed twice on the 7th and 14th days.
In the final stage of the secondary fermentation, the temperature of the fermented product was 55 ° C., the pH was 7.5, and the water content was 40%.
On the 21st day, which is the final day of the second fermentation, the entire fermented product was transferred to the finished fermentation space with a shovel loader.

  The space for performing the finishing fermentation process is almost the same as the primary fermentation space in both the container and the structure size, but a self-propelled automatic turning device is installed. The turn-over was performed while aeration for 7 hours in the day of the week. Stopped at night. The data measured in the final stage of the final fermentation process showed that the temperature of the fermented product was 20 to 30 ° C., the pH was in the range of 6 to 8, and the water content was 30 to 40%. Although it was not exactly the same at several measurement points, it was in this range. At noon on the 7th day, a small part of the fermented product was transferred to a sieving step.

In the sieving step, a 7 mm sieve was applied.
As the fermentation confirmation step described in the present embodiment, the cross section was cut so that the cross section of the central part of the small mountain-like volume of the granular material that passed through the sieve could be observed.
FIGS. 7 to 9 show photographs of a cross-section at the center of a granular small volume that has passed through a sieve.
The inner layer portion (the portion inside the surface layer portion of about 2 cm) in the central section looked whitish. When touched, it was warm and somewhat exothermic. (Such color and temperature were not recognized in the surface layer.)
Since this phenomenon can be interpreted as the function of nitrifying bacteria with a slow growth rate, the fermentation process was terminated.
Then, the entire amount of the fermented product in the finishing fermentation process was transferred to a sieving process, and was passed through a 7 mm sieve to divide it into sieving granules and non-passing coarse products.

The coarse product was transferred to the raw material space as a return chip and used as the next raw material. The granulate was subjected to a fermentation process at the micro level as a final finishing treatment. Here, the powdery body was rolled on a wide plastic sheet and left for 5 days until no heat generation was felt.
An organic fertilizer was produced as described above.

Example 2 (sludge, tea leaves)
Each step was performed in the same manner as in Example 1 except that sludge and tea leaves were used as organic fertilizer raw materials.
In the fermentation confirmation process, when it was cut so that the cross-section of the central part of the small hill-like volume of the granular material that passed through the sieve could be observed, the whitish part on the inner layer part (the part inside the surface layer part of about 2 cm) of the central part cross-section Was not recognized.
In this case, since the secondary fermentation process or the finish fermentation is insufficient, the process of repeating the fermentation at the macro level was performed again.

The present invention is not limited to the above description.
For example, in the method for producing an organic fertilizer according to the present invention, macro-level fermentation is performed by primary fermentation, secondary fermentation, and finish fermentation, but may be performed more finely.
In addition, various modifications can be made without departing from the scope of the present invention.

  The method for producing an organic fertilizer of the present invention can be applied to a method for producing an organic fertilizer by fermenting an organic fertilizer raw material with microorganisms to obtain an organic fertilizer.

FIG. 1 is a flowchart showing steps of a method for producing an organic fertilizer according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of a composting facility for carrying out the method for producing organic fertilizer according to the embodiment of the present invention. FIG. 3 is a schematic diagram of a cross-sectional view of a mountain-shaped deposit of a granular material portion (fluid passage portion) after a sieving step according to an embodiment of the present invention. FIG. 4 is an electron micrograph of a cut surface of a new wood chip. FIG. 5 is an electron micrograph of bacteria attached to the return tip. FIG. 6 is an electron micrograph of bacteria in organic fertilizer (finished product). FIG. 7 is a photograph of a cross-section at the center of a granular small volume that has passed through a sieve. FIG. 8 is a photograph of a cross-section at the center of the granular small volume that has passed through the sieve. FIG. 9 is a photograph of a cross-section at the center of the granular small volume that has passed through the sieve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Mixing yard 21 ... Unused chip storage place 22 ... Circulation chip storage place 30 ... Primary fermenter 31-38 ... Fermenter 40 ... Secondary fermenter 41-44 ... Fermenter 50 ... Finish fermenter 60 ... Screening and Micro level fermenter

Claims (5)

A method for producing an organic fertilizer by fermenting an organic fertilizer raw material with microorganisms to produce an organic fertilizer,
A step of mixing an organic fertilizer raw material that is at least one of sewage sludge and animal and plant residues and wood chips including return chips, excluding sludge derived from animals other than humans whose safety has not been confirmed ;
A step of fermentation of the mixture of the wood chips and the organic fertilizer material,
Sieving the mixture and separating it into the return tip and a sieve passage;
Cutting the pile of deposits of the sieve passage section, observing the cross section, and determining the progress of fermentation by confirming that a white portion is formed inside the pile ; and
Until it said inside white going on part of the mountain sieve passage portion of the deposits are formed and aged by fermentation of the sieve passage portion, the method of manufacturing the organic fertilizer and a step of an organic fertilizer. 2. The organic fertilizer according to claim 1, wherein in the step of fermenting and ripening the sieve passage part, the contact between the sieve passage part and the atmosphere is promoted to promote the growth activity of microorganisms remaining in the sieve passage part. Production method. In the step of fermenting and ripening the sieve passage part, at least the sieve passage part is spread on a sheet and cut back, or by putting the sieve passage part in a container and stirring, the sieve passage part and The method for producing an organic fertilizer according to claim 2 , which promotes contact with the atmosphere. Claims fermenting a mixture of the wood chips and the organic fertilizer material is, the primary fermentation process, has a secondary fermentation step and finishing the fermentation process, carried out aeration and crosscut to perform fermentation to the mixture The manufacturing method of the organic fertilizer in any one of claim | item 1-3 . As the step of confirming the progress of the fermentation, a part of the mixture during the finish fermentation is extracted, and is separated into the return chip and the passage portion through the sieving step, and the pile of deposits in the obtained passage portion is obtained. It is formed and observing the cross section by cutting the mountain, according to judges claim 4 progression of the fermentation by the amount of heat generated from it and the mountain interior white going on part of the mountain is formed Manufacturing method of organic fertilizer.