Method for producing decomposable compost block, decomposable compost block, and method of preventing seaweed bed depletion using decomposable compost block

Abstract

To provide a method for preventing seaweed bed depletion in a sea area of a predetermined range by installing a decomposable compost block in seawater and making use of nutrient salt to be eluted, the block, and a production method thereof.SOLUTION: A method for producing decomposable compost blocks includes: a step of mixing a woody material and fish processed residue; a primary fermentation step of fermenting while agitating the mixed woody material and the fish processed residue; and a secondary fermentation step of fermenting the mixture while lowering the temperature gradually to decompose a sparsely-decomposable polymeric organic substance that has not been decomposed in the primary fermentation. A producing step of solidifying the mixture as a decomposable compost block includes: an additive provision step of adding, relative to the total weight, 8-12 wt.% of solidification material, 20-25 wt.% of a metal material containing steel slag for adjusting the specific gravity and accelerating solidification, and 0.5-1.0 wt.% of a thickening material containing guar gum as a binding material; a step of agitating the material subjected to completion of the secondary fermentation and the additives; a step of molding the material; and a step of subjecting the material to stand still for a predetermined period of time to be solidified.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates mainly to a compostable block that is installed in the ocean and releases nutrients necessary for the growth of seaweed into the surrounding area, a method for manufacturing the compostable block, and a method for preventing rocky shore denudation using the compostable block. [Background technology]

[0002] Seaweeds such as kelp, wakame, and sargassum are large algae that can grow to several meters or more in size. These large algae have a high capacity to produce organic matter through photosynthesis, and by growing in colonies over a wide area on rocky areas, they form seaweed beds that provide habitats and spawning grounds for a variety of fish and shellfish.

[0003] However, in recent years, such seaweed beds have been decreasing along the coasts of Japan, causing problems such as a phenomenon known as "isoyake" (barren seaweed), in which kelp and other seaweed colonies decrease and become barren, and "discoloration," in which kelp and wakame seaweed become paler and less valuable as a product.

[0004] There are various possible causes for this, but the main ones are thought to be high water temperatures, a nutrient-poor marine environment, and the feeding activities of herbivorous animals such as sea urchins that eat seaweed. In particular, the issue of malnutrition is thought to be largely due to a decrease in the supply of iron and nutrients necessary for seaweed growth, such as iron and nutrients in the humus that formed from the accumulation of fallen leaves, caused by river bank construction, the construction of dams upstream, and the felling of broad-leaved trees upstream of rivers that flow into the sea. To address this issue, measures such as the use of fish reefs and the supply of fertilizer (nutrient salts) are effective as background technologies, but they have not yet completely eliminated the problem of rocky shore denudation. Therefore, various methods have been devised to replenish nutrients in marine areas.

[0005] For example, Patent Document 1, "Structure and manufacturing method for utilizing marine resources," discloses a technology in which thinning materials are crushed and fermented, then mixed with marine product materials and further fermented, and the bagged product is laid in the sea area to replenish nutrients.

[0006] However, the technology described in Patent Document 1 involves packing materials containing nutrients into bags and laying them in the sea, which has the disadvantage that the nutrient components dissolve quickly and the effect of replenishing nutrients stops in a relatively short period of time.

[0007] A technique that addresses this issue is disclosed in Patent Document 2. Patent Document 2, "Structure and manufacturing method for utilizing marine resources," discloses a technology in which thinning materials are crushed and fermented, then mixed with marine product materials and further fermented, and then a binder is added, the mixture is poured into a formwork, solidified into blocks, and laid in the sea to replenish nutrients.

[0008] According to the technology of Patent Document 2, the elution of nutrients is maintained for a relatively long period of time, which makes it possible to promote the growth of seaweeds over the long term. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-139174 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-239396 Summary of the Invention [Problem to be solved by the invention]

[0010] However, the technology in Patent Document 2 uses fermented plant materials such as thinning wood and green leaves, so the amount of nutrients is insufficient and the effect of preventing seaweed erosion is not necessarily high. In addition, in the technology of Patent Document 2, paragraph 0017 states, "In this example, primary fermentation is carried out after crushing, but this step is not essential. However, for the purpose of activating seaweed, it is desirable to use plant material that has been fermented." This suggests that the significance of converting organic compounds into inorganic nutrients through the fermentation process is not emphasized.

[0011] Furthermore, the technology of Patent Document 2 also discloses a process in which, after fermenting a plant material, a marine product material is added and fermented again, as shown in FIG. In this regard, there was a problem in that after the fermentation of the plant material was completed, the seafood material was added and fermented again (because the ratio of the material to be fermented to the total weight was reduced), and it was difficult to sufficiently ferment the organic compounds contained in the seafood material and convert them into inorganic nutrients. Furthermore, if fermentation is insufficient and organic matter remains, it dissolves and is not absorbed by algae, which can lead to problems such as water pollution and red tides.

[0012] Furthermore, in the technology of Patent Document 2, the fermentation process of plant material is described as follows: "After the primary crushing, the crushed material was covered with a vinyl sheet and subjected to primary fermentation for one month. (Omitted) The secondary fermented material was subjected to secondary crushing using a crusher set to crush finer than the primary crushing, to prepare the plant material. In this example, primary fermentation is carried out after crushing, but this step is not essential." (paragraph 0017). However, there is no description of the relationship between the length of primary and secondary fermentation or temperature control, and there is insufficient consideration of the impact that the relationship between the two has on the conversion of organic compounds into nutrients.

[0013] Furthermore, in the technology of Patent Document 2, since the marine product material is fermented after the fermentation of the plant material is completed, it becomes necessary to shorten the fermentation time compared to fermenting the combined weight of both materials. In fact, regarding this point, it is stated that the fermentation time after adding the seafood ingredients should be "approximately 24 hours, preferably 12 to 48 hours (paragraph 0029)." Because the fermentation is completed at a relatively high temperature and in a short time, there is the problem that it is difficult to sufficiently ferment the organic compounds contained in the seafood ingredients and convert them into inorganic nutrients.

[0014] Furthermore, the technology of Patent Document 2 uses starch for solidification, but when laid in the ocean, the rate at which nutrients dissolve is too fast, causing the marine resource utilization structure to dissolve early, and there is a problem that a long-term, sustainable effect of eluting nutrients cannot be expected. More specifically, when solidifying fermented materials into blocks, the issue is what solidification material should be added, and in what amount, to ensure sufficient leaching of nutrients and sustained leaching over a long period of time, such as several months.

[0015] Therefore, the present invention aims to provide a compostable block 100 that can quickly supply inorganic nutrients such as nitrate nitrogen and phosphate phosphorus, which are nutrients for seaweed, and can be sustained for a long period of time.

[0016] Furthermore, the present invention aims to optimize the selection of materials, the mixing ratio, and the fermentation method to maximize the inorganic conversion of organic compounds contained in the materials into inorganic nutrients, thereby increasing the ratio of active ingredients (inorganic nutrients) contained in the compostable block 100. More specifically, the objective is to establish a method for maximizing the mineralization of organic compounds contained in the materials and converting them into inorganic nutrients by optimizing the relationship between the timing of mixing plant materials and marine materials and the temperature conditions and fermentation time of the primary and secondary fermentations.

[0017] In addition, the present invention aims to optimize the selection and addition ratio of solidification material in order to optimize the balance between the dissolution rate and duration of inorganic nutrients from the compostable block 100. [Means for solving the problem]

[0018] In order to achieve the above object, the first invention is: A method for producing compostable blocks for preventing rocky shore denudation in a predetermined area of ​​the sea, comprising: placing compostable blocks in the ocean; and utilizing nutrients eluted from the compostable blocks into the surrounding seawater. The manufacturing process of the compost, which is the raw material of the compostable block, includes the following steps: A process of mixing a wood-based material made from wood including wood chips or sawdust with seafood processing residue derived from seafood processing; A primary fermentation step in which the mixed wood-based material and the seafood processing residue are fermented while being stirred to produce a primary fermented material; A secondary fermentation process is a process for decomposing the persistent high molecular weight organic matter that was not decomposed in the primary fermentation process, in which the primary fermentation material is fermented while gradually lowering the temperature from the temperature increased in the primary fermentation process to produce a secondary fermentation material, As a manufacturing process for solidifying the generated secondary fermentation material into a compostable block, With respect to the total weight of the secondary fermentation material produced in the secondary fermentation step, an additive addition process in which 8 to 12 wt % of a solidifying agent for solidifying into a block, 20 to 25 wt % of a metal material containing steel slag for adjusting the specific gravity and promoting solidification, and 0.5 to 1.0 wt % of a thickening agent containing guar gum as a binder are added as additives; A step of stirring the secondary fermentation material and the additive; A step of pressing the mixture of the secondary fermentation material and the additives after the stirring into a predetermined shape or a step of filling it into a mold; The method is characterized by including a step of leaving the mixture of the secondary fermentation material and the additives after the stirring for a predetermined period of time to solidify.

[0019] The second invention is: The primary fermentation step is primary fermentation at a premises, It is a fermentation process that takes place above ground at a temperature of approximately 60-80°C for a period of approximately 2-3 months. The method for producing the compostable block according to the first aspect of the present invention is characterized by the following.

[0020] The third invention is The primary fermentation step is a primary fermentation using a fertilizer manufacturing machine equipped with a rotation mechanism for stirring, A step of fermenting the fertilizer using the fertilizer manufacturing machine at a temperature of approximately 70 to 80 ° C for a period of approximately two weeks. The method for producing the compostable block according to the first aspect of the present invention is characterized by the following.

[0021] The fourth invention is The secondary fermentation step In order to decompose the hardly decomposable polymer organic matter that was not decomposed in the primary fermentation, the primary fermentation material is fermented while gradually lowering the temperature from the temperature increased in the primary fermentation step to produce a secondary fermentation material, The fermentation temperature is set to be at least 10°C lower than the fermentation temperature in the primary fermentation step. The method for producing the compostable block according to the first aspect of the present invention is characterized by the following.

[0022] The fifth invention is As the solidification material in the manufacturing process for solidifying the generated secondary fermentation material into a compostable block, Using 8 to 12% by weight of magnesium oxide based on the total weight of the secondary fermentation material produced in the secondary fermentation step and the additives; The method for producing the compostable block according to any one of the first to fourth aspects of the present invention is characterized by the following.

[0023] The sixth invention is In the method for producing a compostable block according to the fifth aspect of the present invention, By using magnesium oxide as the solidifying material in the manufacturing process for solidifying the generated secondary fermentation material into a compostable block, The magnesium oxide reacts with water to be converted into magnesium hydroxide by a hydration reaction, and The magnesium oxide reacts with the added steel slag to promote crystalline bonding, thereby enhancing solidification; This is a method for producing a compostable block, characterized by the above.

[0024] The seventh invention is A secondary fermentation material that is a fermentation product of mixed wood chips and fishery processing residue, in which organic compounds are decomposed into inorganic nutrients; The additives include 8 to 12% by weight of a solidifying material for solidifying into a block, 20 to 25% by weight of a metal material including steel slag for adjusting the specific gravity and promoting solidification, and 0.5 to 1.0% by weight of a thickening material including guar gum as a binder, relative to the total weight including the secondary fermentation material. The compostable block is characterized by:

[0025] The eighth invention is As the solidification material for solidifying the secondary fermentation material into a compostable block, Using 8 to 12% by weight of magnesium oxide based on the total weight of the secondary fermentation material and additives; The compostable block according to the seventh invention is characterized by the following.

[0026] The ninth invention is The magnesium hydroxide derived from the magnesium oxide is contained, and solidification is strengthened by the crystalline bonding between the magnesium oxide and the added steel slag. The compostable block according to the eighth invention is characterized by the following.

[0027] The tenth invention is A seaweed bed cultivation system is provided in which the compostable block according to any one of the seventh to ninth inventions is placed in a predetermined sea area to cultivate a seaweed bed.

[0028] The eleventh invention is This is a method for preventing rocky shore bleaching, characterized by placing the compostable blocks described in any one of claims 7 to 9 in a specified sea area and promoting the creation of seaweed beds by eluting nutrients.

[0029] The twelfth invention is A method for promoting the creation of a seaweed bed by placing the compostable block according to any one of claims 7 to 9 in a predetermined sea area and eluting nutrients, This method for preventing rocky shore bleaching is characterized by laying the compost-degradable blocks so that the margin, which is an index showing the ability to produce seawater containing sufficient nutrients for seaweed growth, is approximately 10 or more. [Effects of the Invention]

[0030] According to the present invention, a compostable block can be provided that is based on plant and marine materials and undergoes primary fermentation at a relatively high temperature, followed by secondary fermentation in which the temperature is gradually lowered from the primary fermentation, thereby minimizing the residual organic compounds and eliminating the substances that cause red tides, and that is rich in nutrients due to sufficient mineralization.

[0031] In addition, by using innovative solidification materials, it is possible to achieve both rapid elution of nutrients and long-term sustainability, thereby ensuring sufficient concentrations of nutrients over the long term and enabling seaweed to settle and grow. [Brief explanation of the drawings]

[0032] [Figure 1] This is a diagram showing an example of conventional technology, taking Patent Document 2 as an example, and shows a process for producing a structure for utilizing marine resources, which includes a step of adding marine product material and fermenting it again after completing the fermentation of plant material. [Figure 2] This figure shows an overview of the manufacturing process of the present invention, and is an example of a process for producing a compostable block 100 by mixing seafood processing residue and wood-based material, carrying out primary fermentation, carrying out secondary fermentation under conditions different from those of the primary fermentation, and then adding specified additives. [Figure 3] FIG. 3 is a diagram showing the contents of the present invention, illustrating an example of the process when a soil pit is used in the composting (primary fermentation) of step S2-3 in FIG. 2. [Figure 4] FIG. 3 is a diagram illustrating the contents of the present invention, showing an example of a process in which a fertilizer production machine is used in the composting (primary fermentation) of step S2-3 in FIG. 2. [Figure 5] FIG. 3 is a diagram showing the contents of the present invention, illustrating an example of detailed contents of the composting (secondary fermentation) step in step S2-4 of FIG. [Figure 6] FIG. 2 is a diagram illustrating the present invention, showing an example of detailed steps of the steps S2-5 and S2-6 of FIG. 2 for producing a compostable block 100. [Figure 7] This figure shows the contents of the present invention, and is an example of the actual state of composting (primary fermentation) in step S2-3 of Fig. 2. A) shows the state of primary fermentation when a soil pit is used, and B) shows the state of primary fermentation when a composting machine is used. [Figure 8] This figure shows the contents of the present invention, and is a diagram showing an example of the actual state of composting (secondary fermentation) in step S2-4 of Figure 2. A) shows the state of secondary fermentation when using a soil pit, and B) shows the state of the entire factory. [Figure 9] FIG. 1 is a diagram illustrating the contents of the present invention, showing an example of the production process of steps S2-5 to S2-6 in FIG. 2, and more specifically, showing an example of the actual state of the moisture adjustment and stirring process of step S6-5 in FIG. [Figure 10] This figure shows the contents of the present invention, and is an example of the process for producing a compostable block 100 in step S2-6 of Figure 2, and more specifically, an example of the actual state of the molding process in step S6-6 of Figure 6 when a press is used. [Figure 11] FIG. 1 is a diagram illustrating the present invention and shows an example of a compostable block 100 produced. [Figure 12]This figure shows the contents of the present invention, and is an example of an actual situation in which the produced compostable block 100 is dumped into a specified sea area to fertilize the sea area. [Figure 13] FIG. 1 is a diagram illustrating the contents of the present invention, showing an example of the content of active ingredients in a compostable block 100 having a diameter of 25 cm, a height of 19 cm, and a weight of 15 kg. [Figure 14] This figure shows the effectiveness of a system for preventing sea erosion using the compost-degradable blocks of the present invention. (a) shows an example of data for an ideal nutrient concentration (nutrient concentration off the coast of the Sea of ​​Japan (February)), and (b) shows an example of the amount of seawater that would be eluted with nutrients from the compost-degradable blocks 100 of the present invention when converted to seawater with an ideal nutrient concentration. [Figure 15] This figure shows the effectiveness of the rocky shore denudation prevention system using the compostable blocks of the present invention. It also shows the margin for leaching of active ingredients such as nutrients in relation to the amount of seawater in an area when a predetermined number of compostable blocks 100 are laid, depending on the average depth of the area. Figure A) shows the margin for nutrients when 300 compostable blocks 100 are laid when the average depth is 10 m, and Figure B) shows the margin for nutrients when 300 compostable blocks 100 are laid when the average depth is 20 m. [Figure 16] This figure shows the effect of the rocky shore erosion prevention system using the compostable blocks of the present invention, and shows how the margin in terms of phosphate-phosphorus changes depending on the number of compostable blocks 100 laid. [Figure 17] This figure shows the effect of the rocky shore denudation prevention system using the compost-degradable blocks of the present invention, and shows how the margin in terms of nitrate nitrogen changes depending on the number of compost-degradable blocks 100 laid. [Figure 18] This figure shows the effect of the system for preventing sea erosion using the compostable blocks of the present invention, and shows how sea erosion is improved after the compostable blocks 100 are laid in a specified sea area 200. [Figure 19] FIG. 1 is a diagram showing the effect of the fermentation method used in the method for producing compostable blocks of the present invention, illustrating the roles and effects of primary fermentation and secondary fermentation. [Figure 20] This figure shows the characteristics of the manufacturing method for compostable blocks of the present invention, and shows how the solidification strength and ease of dissolution in seawater change depending on the mixing ratio when magnesium oxide is mixed as a solidification material. [Figure 21] FIG. 1 is a diagram illustrating the characteristics of the method for producing compostable blocks of the present invention, showing how the elution of nutrients changes depending on the addition ratio (mixing ratio) of solidifying material. [Figure 22] This figure shows the characteristics of the method for producing compostable blocks of the present invention, and is a conceptual diagram showing the solidification mechanism by the hydration reaction of magnesium oxide and the pozzolanic reaction in which magnesium oxide reacts with each of the main components contained in separately added steel slag when magnesium oxide is used as the solidification material.

[0033] <Terminology> ◇Fishery processing residues include fish and shellfish-derived innards, skin, bones, fish meal, broth, and fish solubility generated as a by-product when squeezing meal, all of which are generated during the fishery processing process. Any residue of animal matter is sufficient, and may include food waste as well as waste animal matter such as excrement and innards from poultry farms and livestock. ◇Wood-based materials are materials derived from trees and plants, including wood chips, sawdust, fallen leaves, and other plant leaves and roots. They are used to absorb oxygen and promote fermentation, and to ferment the wood-based materials themselves to provide them with nutrients.

[0034] ◇A landslide site is a relatively large area, such as the ground or a structure made of concrete. A fertilizer machine is a device equipped with a rotary blade to mix the contents, a power mechanism to rotate the rotary blade, and a temperature control mechanism such as a heater to maintain a constant temperature. Excrement and food waste are placed into the device, and the rotating field is stirred, allowing aerobic microorganisms to decompose and process the excrement and food waste. For example, it can be used as a composting machine such as a food waste processor, or a bio-toilet.

[0035] Fermentation is the process by which organic nitrogen, such as proteins and amino acids contained in animal matter such as fishery processing residues, is converted by microorganisms such as bacteria into inorganic nitrogen, such as ammonia and nitrate, which can be absorbed by seaweed. * A solidifying agent is a material used to solidify materials after fermentation is complete, and in this invention, magnesium oxide is mainly used. Magnesium oxide is a material obtained by thermal decomposition of carbonates, nitrates, hydroxides, etc. Magnesium oxide fired at low temperatures is called light-burned (or pre-burned) magnesia, and magnesium oxide fired at high temperatures is called hard-burned (or heavy-burned) magnesia.

[0036] ◇Steel slag is a material produced as a by-product in the manufacturing process of steel products. It can be broadly divided into blast furnace slag, which is produced when iron ore is melted and reduced in a blast furnace, and steelmaking slag, which is produced during the steelmaking stage when iron is refined. Steel slag is primarily composed of lime (CaO) and silica (SiO2), but also contains alumina (Al2O3), magnesium oxide (MgO), and a small amount of sulfur (S) derived from blast furnace slag, as well as iron oxide (FeO) and magnesium oxide (MgO) derived from steelmaking slag. Its specific gravity is approximately 2.6, roughly the same as that of natural soil and sand. Guar gum is a water-soluble natural polysaccharide extracted from the endosperm (more precisely, the cotyledon) of guar beans, and has glue-like properties. In this invention, it is used to bind materials together when solidifying with a solidifying agent.

[0037] ◇Hydration is the reaction that occurs when materials such as magnesium oxide and calcium oxide come into contact with water. As a result of the hydration reaction, compounds such as magnesium hydroxide and calcium hydroxide are produced. The newly precipitated substances resulting from hydration are called hydration products, and it is known that strength is developed as these hydration products fill the gaps between the materials. A typical example is the hydration reaction that occurs when water is added to cement whose main component is tricalcium silicate [(CaO)3(SiO2)], and the main component of the cement reacts with the water to form new compounds, which slowly harden while combining with the aggregate to form concrete.

[0038] ◇Pozzolans are fine silica powders such as fly ash (a type of ash produced when burning coal), clay silicate, diatomaceous earth, and volcanic ash. They are not hydraulic in themselves, but when mixed with calcium oxide or magnesium oxide, they react with the calcium hydroxide or magnesium hydroxide produced by hydration to form insoluble compounds, a so-called pozzolanic reaction.

[0039] ◇Pozzolanic reaction is a phenomenon that occurs when glass-based materials (fly ash, silica fume, volcanic ash, etc.) are mixed with calcium oxide or magnesium oxide, and the reaction occurs as the hydration reaction progresses. The pozzolanic reaction is a reaction in which dissolved Si and Al from the glass-based material are absorbed into the hydrates (calcium silicate phase (commonly known as CSH phase) and calcium hydroxide (containing ionized Ca2+)) near the particles of the glass-based material (see (a) and (b) in Figure 22(1)), which changes the material into a low-Ca CSH phase with a high Si and Al content (see (b) and (c) in Figure 22(2)). During this pozzolanic reaction, the number of granules with a particle size of 20 to 30 nm, which are the constituent units of the CSH phase present near the particles of the glass-based material, increases, filling the tiny voids (water voids) formed by the hydration reaction (see Figure 22(3)). This water void filling action is the densification phenomenon of the structure caused by the pozzolanic reaction, and has the effect of accelerating solidification.

[0040] Nutrients are nutrients required for seaweed growth. In order for seaweed to settle and grow on rocky areas, the presence of seaweed spores and nutrients are necessary. For this reason, simply ensuring the concentration of nutrients may not eliminate seaweed denudation. However, in areas where seaweed spores are present, ensuring the concentration of nutrients can eliminate seaweed denudation, although this can vary depending on the temperature, current speed, and other influences of sunlight. (See the report of the Fisheries Agency's Fisheries Infrastructure Development Research Commissioned Project for 2019, "Development of a method for selecting suitable locations for creating fishing grounds based on elucidation of marine environmental conditions favorable for the growth of natural kelp," published in March 2020.) Nutrients include nitrate nitrogen, nitrite nitrogen, and phosphate phosphorus. It is known that ocean nutrient concentrations vary depending on the region and season (water temperature) (see the report above).

[0041] ◇Margin is an index that shows the ability to produce seawater containing enough nutrients to grow seaweed. More specifically, when nutrients are leached from a specified number of compost-degradable blocks into a specified sea area to generate seawater containing the specified nutrients, this number indicates how many times the weight of the nutrients contained in the compost-degradable blocks can be converted into standard seawater containing enough nutrients for seaweed to grow. For example, it is known that the nutrient concentration sufficient for seaweed growth is a nitrate nitrogen concentration of 6.6 μmol / liter. If the nitrate nitrogen (36 g) from a compostable block (15 kg) is dissolved into seawater, 5,700 tons of seawater containing nitrate nitrogen at the above concentration can be produced. In this case, assuming an area of ​​sea of ​​1 hectare, or 100m x 100m, with an average depth of 10m, and ignoring the weight of salt, the amount would be 100m x 100m x 10m = 100,000 tons. If 300 compostable blocks were laid in this area, each block would be able to handle 333 tons of seawater. In this case, the margin is calculated to be 5,700 / 333 tons = 17.1 times. DETAILED DESCRIPTION OF THE INVENTION

[0042] Examples of the present invention will be described below. The configurations, drawings, and tables in the description are merely examples, and can be applied to other shapes and configurations.

[0043] 1. Issues with conventional technology First, the prior art of Patent Document 2 will be described with reference to FIG. In conventional technology, plant-based materials such as forest products and grain by-products, primarily consisting of wood chips made from wood materials including fallen leaves, wood chips, and thinned wood, are first prepared as raw materials (step S1-1), and then crushed using a crusher (step S1-2).

[0044] After the primary crushing, the crushed material is covered with a vinyl sheet and allowed to undergo primary fermentation for approximately one month (step S1-3).Then, the primary fermented material is subjected to secondary crushing using a crusher set to crush the material finer than the primary crushing (step S1-4), and if necessary, secondary fermentation is allowed (step S1-5).

[0045] Next, a marine product material is prepared (step S1-6) and is put into a kneading device having a stirring function together with the fermented and secondarily crushed plant material (step S1-7). This kneading device has a screw-shaped agitator, and the mixed materials are fermented and mixed by rotating the screw with a motor.

[0046] This fermentation and blending process is completed in approximately 24 hours, with the temperature being controlled to be between approximately 40 and 70°C. Next, in order to solidify the fermented material and form a structure, starch is added as a binder to the fermented and mixed material and then kneaded (step S1-8). Finally, the material is poured into a mold, cooled and solidified, and a structure for utilizing marine resources is produced (steps S1-9, S1-10).

[0047] Indeed, this method is thought to have a certain effect on preventing sea erosion. However, the research team of the present invention felt that this prior art contained a statement that "However, in the present invention, the addition of marine product ingredients is not essential, and the effect of activating marine resources can be obtained using plant materials alone" (paragraph 0022), and that this may have overlooked the effect of using marine product ingredients.

[0048] The research team behind this invention found that the mineralization rate of marine materials through fermentation is higher than that of plant materials (the mineralization rate for plant materials such as rice bran is only about 40%, while that for marine materials such as fish meal is over 80%), and that it is expected that organic matter can be effectively mineralized and the proportion that can be supplied as nutrients that are easily absorbed by seaweed can be increased. Therefore, after extensive research into the timing of mixing the marine product material and the plant material and the fermentation method, we arrived at the method of the present invention, which will be explained below using Figure 2 and subsequent figures.

[0049] 2. Overview of the manufacturing process of the present invention FIG. 2 is a diagram showing an overview of the manufacturing process of the present invention, which shows an example of a process in which marine processing residue and wood-based material are mixed, followed by primary fermentation, secondary fermentation under conditions different from those of the primary fermentation, and then predetermined additives are added to produce a compostable block 100.

[0050] First, wood-based materials and fishery processing residues are prepared as raw materials (step S2-1). As the wood-based material, wood chips and sawdust were selected from the viewpoint of fermenting the wood-based material itself to produce inorganic nutrients, and of shredding the wood-based material into fragments to create tiny gaps that provide air to aerobic microorganisms, but other plant materials can also be used. From the viewpoint of producing inorganic nutrients by fermenting the woody material itself, it is desirable to use broad-leaved trees, but the present invention is not limited to this.

[0051] Examples of fishery processing residues that can be used include bones, skin, and internal organs from fish processing, as well as fish solubility, a by-product obtained when squeezing fish meal during fish meal production. As mentioned above, the use of fishery processing residues is based on the fact that the mineralization rate of marine materials through fermentation is higher than that of plant materials (the mineralization rate for plant materials such as rice bran is only around 40%, while that for marine materials such as fish meal is over 80%).

[0052] Next, the raw materials, wood-based materials and seafood processing residues, are mixed and mixed well (step S2-2). The ratio of wood-based materials to fishery processing residues should be 5 cubic meters of wood-based materials to 2 tons of fishery processing residues. When wood chips are used as wood-based materials, the specific gravity of the wood chips varies depending on the moisture content, but is generally around 200 grams per liter, so 5 cubic meters is estimated to be around 1 ton, and a weight ratio of around 1:2 is desirable. However, this ratio is not limited to the above numerical values, and even if the weight ratio is 1:1 to 1:3, it is possible to produce a compostable block 100 containing the required amount of nutrients.

[0053] Next, the mixed raw materials are subjected to primary fermentation at a relatively high temperature of approximately 60 to 80° C. (step S2-3). Even after the primary fermentation has progressed, some of the various organic compounds contained in the raw materials do not change into inorganic forms and remain as organic matter. Therefore, through repeated trial and error, the research team of the present invention discovered that the rate of mineralization can be increased by gradually lowering the temperature that was raised during the primary fermentation over a long period of several months while performing the secondary fermentation (step S2-4).

[0054] Next, additives including solidifying agents, density adjusting agents to prevent the material from being washed away by currents on the seabed, and binders are added to the material that has completed secondary fermentation (step S2-5), and the material is then placed in a formwork and held there for a certain period of time, or pressed in a press to produce a compostable block 100 (step S2-6). The resulting compostable blocks 100 are added in an appropriate amount to fertilize the sea (step S2-7) so that the concentration of nutrients necessary for the establishment and growth of seaweed is achieved, and the seaweed is then allowed to grow (step S2-8).

[0055] In the prior art of Patent Document 2, marine product materials are not required, and even when marine product materials are added, they are added after the fermentation of plant materials is completed, which does not necessarily ensure a sufficient mineralization rate. In contrast, in the present invention, in order to increase the mineralization rate, fermentation is carried out using a mixture of wood-based material and marine processing residues as the material from the beginning.

[0056] Furthermore, the present invention is characterized in that the fermentation process is divided into a primary fermentation step in which fermentation is carried out at a slightly higher temperature range, and a secondary fermentation step in which the temperature is lowered, thereby increasing the rate of mineralization of organic matter, thereby increasing the proportion of nutrients and improving the effectiveness of preventing rocky shore bleaching. In addition, by devising the content and ratio of the solidification material used to solidify the fermented raw materials, it is possible to achieve both a nutrient leaching rate and leaching period, allowing the nutrients contained in the compostable block 100 to quickly leach out, ensuring the concentration of nutrients necessary for the marine area, and enabling leaching over a long period of several months.

[0057] Here, nutrients refer to inorganic salts that are essential for the growth and reproduction of living organisms. Marine plants often lack nitrogen and phosphorus, so these are called nutrients. Potassium is present in sufficient concentrations in seawater, so a deficiency is not a problem. Manganese, copper, iron, and other elements are taken up by marine plants in small amounts compared to nitrogen and phosphorus, but because they are essential elements, they are called trace elements, trace metals, or trace nutrients, and are sometimes included in nutrients.

[0058] Seaweed absorbs these nutrients from seawater and grows and reproduces through photosynthesis. Because of this, the nutrients in the seawater can become depleted in the euphotic zone. When seaweed and phytoplankton die, they sink to the bottom of the seawater and decompose into inorganic nitrogen and phosphorus.

[0059] Nitrogen can be broadly classified into inorganic and organic forms. Inorganic nitrogen includes ammonia nitrogen (NH4-N), nitrite nitrogen (NO2-N), and nitrate nitrogen (NO3-N), and the sum of these is called dissolved inorganic nitrogen (DIN). Phosphorus can also be classified into inorganic and organic forms. Dissolved inorganic phosphorus (DIP) is mainly phosphate phosphorus (PO4-P). When organic phosphorus is filtered, the filtrate is called dissolved organic phosphorus (DOP), and the residue on the filter paper is called suspended organic phosphorus (POP).

[0060] Seaweed cannot absorb nutrients from the surface of the algae unless they are in an inorganic form, so the nutrients it needs are mainly dissolved inorganic nitrogen (DIN) and phosphate-phosphorus (PO4-P). Nutrients are often expressed in units of moles (mol / L), but because the nutrient concentration in the ocean is low, they are often expressed in μM, which is 1 / 1,000,000 of the original unit.

[0061] 3. Details of the manufacturing process of the present invention 3-1. Primary fermentation process Next, the primary fermentation process in step S2-3 of FIG. 2 will be described. (1) Primary fermentation process using a soil pit Next, the process of primary fermentation using a soil pit will be explained using Figure 3. FIG. 3 is a diagram showing the contents of the present invention, and is a diagram showing an example of the process when a soil pit is used in the composting (primary fermentation) of step S2-3 in FIG.

[0062] Approximately 25 cubic meters of raw material is spread out in one yard (Step S3-1), and the material is aerated every 3 to 7 days to promote the fermentation process of aerobic microorganisms (Step S3-2). The primary fermentation in the fermenting yard is carried out for about three months with the temperature adjusted to be in the range of approximately 60 to 80°C (step S3-3), to produce a material that has completed primary fermentation (step S3-4).

[0063] (2) Primary fermentation process using fertilizer production machinery Next, primary fermentation using a fertilizer production machine will be explained using Figure 4. FIG. 4 is a diagram illustrating the contents of the present invention, showing an example of a process in which a fertilizer production machine is used in the composting (primary fermentation) of step S2-3 in FIG. Using a soil yard allows for the production of a large amount of primary fermentation-completed material at one time, so it is more cost-effective to use a soil yard, but fertilizer production machinery can also be used.

[0064] Although the introduction cost of fertilizer production machinery is high, when using fertilizer production machinery, it is possible to heat the soil using a heater or the like, and maintain a high temperature of approximately 80°C, which leads to an increase in the fermentation efficiency of the microorganisms, and primary fermentation can be completed in a relatively short period of time. First, the mixed raw materials are fed into the fertilizer production machine (step S4-1).

[0065] Approximately 5 cubic meters of raw material is fed into each machine, and several machines are operated. After the raw materials are added, the rotary blades are rotated every few hours to agitate the raw materials, incorporating air and promoting the fermentation action of aerobic microorganisms (step S4-2). Then, the mixture is fermented for approximately two weeks (step S4-3) to produce a material that has undergone primary fermentation (step S4-4).

[0066] 3-2. Secondary fermentation process Next, secondary fermentation using a soil pit will be explained using Figure 5. The organic compounds contained in wood-based materials and fishery processing residues contain components with various properties, and the temperature suitable for fermentation varies depending on the microorganisms that contribute to fermentation. For this reason, it is difficult to sufficiently mineralize organic compounds through primary fermentation at relatively high temperatures alone, and there is a possibility that the necessary nutrient content may not be secured. In addition, it is predicted that organic matter may remain, which could cause adverse effects such as inducing the growth of harmful plankton when the material is laid in the sea.

[0067] Therefore, through repeated trial and error, the research team of the present invention discovered that by changing the fermentation conditions of the material after primary fermentation and conducting a secondary fermentation in which the temperature is gradually lowered, it is possible to mineralize the organic compounds remaining in the primary fermentation.

[0068] In the secondary fermentation process, first, the material that has completed primary fermentation is spread out on a soil pit (step S5-1), and the temperature is gradually lowered (step S5-2) to promote the fermentation activity of microorganisms that become active under conditions different from those of primary fermentation, while promoting actions such as decomposing persistent high molecular weight organic matter in a lower temperature environment than primary fermentation and nitrifying the ammonia generated in primary fermentation into nitric acid (step S5-3).

[0069] The secondary fermentation is continued for approximately 2 to 3 months with stirring to promote the growth of aerobic microorganisms (step S5-4), producing a material in which the decomposition of high molecular weight organic matter has progressed (step S5-5).

[0070] 3-3. Manufacturing process of compostable blocks 100 Next, the process for producing the compostable block 100 using the material that has been fermented and is now highly mineralized will be described with reference to FIG. FIG. 6 is a diagram illustrating the present invention, showing an example of detailed steps of the process for producing the compostable block 100 in steps S2-5 and S2-6 of FIG.

[0071] First, a secondary fermentation-completed material in which the decomposition of high molecular weight organic matter has progressed is prepared (step S6-1), and steel slag is added as an additive to adjust the specific gravity and promote solidification at a ratio of 20 to 25% by weight based on the total weight of the additive and secondary fermentation-completed material (step S6-2). In addition, a solidifying agent is added as an additive at a ratio of 8 to 12% by weight based on the total weight (step S6-3).

[0072] Then, in order to maintain the bond between the secondary fermentation-completed material and the additives during the process until solidification, a thickening or binding material is added at a ratio of 0.5 to 1.0% by weight based on the total weight (step S6-4). Here, various materials such as starch and magnesium oxide are candidates for the solidification material, but it is preferable to use magnesium oxide and adjust the component ratio of magnesium oxide as the solidification material to the total weight to adjust the degree of solidification and adjust the balance between the ease of leaching of nutrients and maintaining the leaching state over a long period of time.

[0073] After adding the above additives to the material that has completed secondary fermentation, the moisture content is adjusted appropriately and the mixture is stirred to mix well (step S6-5), and then the mixture is pressed in a press or filled into a mold and shaped (step S6-6). After a drying process of approximately 0.5 to 1 month, the mixture is solidified (step S6-7), and the production of the compostable block 100 is completed (step S6-8).

[0074] Next, with reference to FIG. 22, we will explain how magnesium oxide acts to solidify materials containing secondary fermentation-completed materials when magnesium oxide is used as a solidifying agent. FIG. 22 is a diagram illustrating the characteristics of the manufacturing method of the present invention. It is a conceptual diagram showing the solidification mechanism by the hydration reaction of magnesium oxide and the pozzolanic reaction in which magnesium oxide reacts with each of the main components contained in the separately added steel slag when magnesium oxide is used as the solidification material.

[0075] The solidification mechanism is firstly, a self-hardening process in which magnesium oxide reacts with the water contained in the material that has completed secondary fermentation and with the added water (hydration reaction), transforming into magnesium hydroxide, and solidifying together with the inorganic nutrients produced by fermentation (see the "hydration reaction" bubble in Figure 22(1)). This hydration reaction occurs immediately after the materials are mixed.

[0076] A second mechanism is that solidification is further promoted by a pozzolanic reaction, in which magnesium ions (Mg2+) generated by the reaction of magnesium oxide with water react with the silica and alumina contained in the separately added steel slag (see the bubble "Pozzolanic Reaction (Layer)" in Figure 22). This pozzolanic reaction also involves a reaction between calcium ions (Ca2+) generated by the reaction of lime (CaO) contained in the steel slag with water. The formation of this pozzolanic reaction layer takes a relatively long period of time, around one month.

[0077] In order to increase the strength of the pozzolanic reaction, it is desirable for the environment to be weakly to strongly alkaline. However, the main components of steel slag are lime (CaO), silica (SiO2), and alumina (Al2O3). The lime (CaO) contained in the steel slag reacts with water to produce hydroxyl groups (OH-), which allows the mixture of materials to remain alkaline (see the bubble "Alkaline environment" in Figure 22(1)).

[0078] Looking at this in more detail, as shown in Figure 22(1), silica (SiO2) and alumina (Al2O3) contained in the steel slag are dissolved, and silica (SiO2) ionizes to form SiO4·4-, and alumina (Al2O3) ionizes to form AlO2-.

[0079] Furthermore, as shown in Figure 22(2), Ca2+ eluted from the steel slag and Mg2+ eluted from magnesium oxide react with SiO4·4- or AlO2- to produce cementitious hydrates, and a pozzolanic reaction layer is formed (see the "filled-in area" in Figure 22(2)).

[0080] As shown in Figure 22(3), a pozzolanic reaction layer spreads across the soil, and new layers are generated one after another, filling the pores that have formed in the gaps in the outer reaction layer. Eventually, the pozzolanic reaction products and cementitious hydrates firmly bond together and become one. This process takes place over a long period of time, lasting more than a month.

[0081] As described above, during the process of magnesium hydroxide production through the hydration reaction of magnesium hydroxide and the process of the pozzolanic reaction between magnesium hydroxide and each of the main components derived from steel slag, solidification involving the secondary fermentation-completed material (inorganic nutrients) is promoted, and compostable blocks are produced.

[0082] By laying an appropriate number of the completed compostable blocks in a designated sea area (step S2-7 in Figure 2), nutrients are leached out, ensuring the necessary nutrient concentration and promoting the proliferation and growth of seaweed (step S2-8 in Figure 2).

[0083] 4. Manufacturing process Next, the manufacturing process was photographed and will be described below with reference to FIGS. Figure 7 shows the contents of the present invention, and is a diagram showing an example of the actual state of composting (primary fermentation) in step S2-3 of Figure 2. A) shows the state of primary fermentation when soil pit 10 is used, and B) shows the state of primary fermentation when compost manufacturing machine 20 is used.

[0084] The area of ​​each yard 10 is approximately 10m in length and width, and in the demonstration experiment, there were 5 to 10 yard areas set up throughout the factory, but this can vary depending on the number of items to be manufactured. The composting machine 20 is equipped with a rotary blade for stirring the contents, a power mechanism for rotating the rotary blade, and a temperature control mechanism such as a heater for maintaining a constant temperature. The composting machine is a device that allows excrement and food waste to be thrown into the machine, and a rotating field is used to stir the waste, which is then decomposed and treated by aerobic microorganisms. For example, a food waste processor or bio-toilet may also be used.

[0085] Figure 8 shows the contents of the present invention, and is a diagram showing an example of the actual state of composting (secondary fermentation) in step S2-4 of Figure 2. A) shows the state of secondary fermentation when using a soil pit, and B) shows the state of the entire factory. FIG. 8 shows how a substantial amount of material that has completed the primary fermentation is spread out and subjected to secondary fermentation.

[0086] FIG. 9 is a diagram showing how a secondary fermentation completed material that has undergone fermentation is mixed and stirred with additives using a mixing mixer 30, and is a diagram showing an example of the production process in steps S2-5 to S2-6 in FIG. 2, or the actual moisture adjustment and stirring process in step S6-5 in FIG. 3. Figure 9 shows that the materials are mixed and stirred by the rotating blades.

[0087] Figure 10 is a diagram showing the contents of the present invention, and is an example of the process for producing a compostable block 100 in step S2-6 of Figure 2, and more specifically, a diagram showing an example of the actual state of the molding process in step S6-6 of Figure 6 when using a press machine 40. FIG. 10 shows how a press 40 is used to mold the compostable block 100, which is being solidified by the solidifying material, into a predetermined shape.

[0088] Figure 11 illustrates the present invention and shows an example of a produced compostable block 100. The top row shows the compostable block 100 molded using a press 40, and the bottom row shows the compostable block 100 molded in a formwork.

[0089] FIG. 12 is a diagram illustrating the contents of the present invention, showing an example of an actual situation in which the produced compostable blocks 100 are dumped into a specified sea area 200 to fertilize the sea area. It has been found that laying about 300 compostable blocks 100 in one sea area can provide a certain level of protection against rocky shore denudation.

[0090] 5. Evaluation of the effectiveness and performance of a system for preventing rocky shore erosion using compostable blocks Next, the effects and performance evaluation of a system for preventing rocky shore denudation, in which compostable blocks 100 are placed in a predetermined sea area to cultivate seaweed beds and prevent rocky shore denudation, will be described with reference to FIGS. FIG. 13 is a diagram illustrating the contents of the present invention, showing an example of the content of active ingredients in a compostable block 100 having a diameter of 25 cm, a height of 19 cm, and a weight of 15 kg. According to FIG. 13, it is found that the water contains components necessary for the growth of seaweed, for example, 36 g of nitrate nitrogen and 570 g of phosphate phosphorus. When looking at the content per 100g, we see that it is 240mg and 3800mg respectively.

[0091] Figure 14 is a graph showing the effects of the present invention, where (a) shows an example of data when the nutrient concentration is ideal (nutrient concentration off the coast of the Sea of ​​Japan (February)), and (b) shows an example of the amount of seawater when the nutrients from the compostable block 100 of the present invention are dissolved into seawater when the nutrient concentration is converted to seawater with an ideal nutrient concentration.

[0092] According to Figure 14 (i), the concentrations of nutrients sufficient for the smooth growth of seaweed are 6.6 μmol / liter of nitrate nitrogen and 0.64 μmol / liter of phosphate phosphorus. On the other hand, as shown in Figure 14 (b), when the nutrient salt concentration is converted to ideal seawater, it can be seen that the amount of seawater that would be required if all of the nutrients in the compostable block 100 of the present invention were to be dissolved into seawater would be 6.6 μmol / L for nitrate nitrogen and 0.64 μmol / L for phosphate phosphorus.

[0093] Based on these figures, the amount of fertilizer to be applied per hectare of marine area is as shown in Figure 15. Figure 15 is a diagram illustrating the effects of the present invention, showing how much margin there is for the leaching of active ingredients such as nutrients when a predetermined number of compostable blocks 100 are laid, depending on the average depth of the sea area where they are laid, based on the amount of seawater in that area.

[0094] Figure 15(a) shows the nutrient allowance when 300 compostable blocks 100 are laid at an average depth of 10m, and Figure 15(b) shows the nutrient allowance when 300 compostable blocks 100 are laid at an average depth of 20m.

[0095] According to Figure 15 (i), if the average depth is 10m, the amount of seawater will be 100,000 tons, and if 300 compostable blocks 100 are laid, the amount of seawater that each block can handle will be 333 tons. In this case, as shown in Figure 14 (b), when considering the fact that 5,700 tons of seawater containing sufficient nitrate nitrogen can be produced, there is a margin of 5,700 / 333 tons = 17.1 times.

[0096] Similarly, when we consider the possibility of producing 19,000 tons of seawater containing sufficient phosphate phosphorus, there is a margin of 19,000 / 333 tons = 57.1 times.

[0097] Furthermore, according to Figure 15 (b), when a similar calculation is performed for an average depth of 20 m, it is found that there is a margin of 8.6 times in terms of nitrate nitrogen and 28.5 times in terms of phosphate phosphorus. Fertilization experiments in several marine areas have shown that if a margin of approximately 10 times or more can be secured, sufficient nutrients can be maintained for approximately six months or more, even taking into account the effects of the tidal currents in the area. Using this margin of 10 as a guideline, it is possible to calculate a rough guideline for how many units should be laid.

[0098] Next, the number of cables to be laid will be described with reference to FIGS. 16 and 17. FIG. 16 is a diagram showing the effect of the present invention, showing how the margin in terms of phosphate-phosphorus changes depending on the number of compostable blocks 100 laid. FIG. 17 is a diagram showing the effect of the present invention, showing how the margin in terms of nitrate nitrogen changes depending on the number of compostable blocks 100 laid.

[0099] According to Figure 16, the range where the margin of phosphate-phosphorus equivalent is 10 or more is shown in the gray area, and although this varies depending on the average depth of the sea area, which is 10 to 20 m, it can be seen that the number of pieces required is approximately 200 to 400 per hectare. Furthermore, according to Figure 17, the range where the margin of nitrate nitrogen equivalent is 10 or more is the part shown in gray, and although this varies depending on the average depth of the sea area, which is 10 to 20 m, it can be seen that the number of units required is approximately 100 per hectare.

[0100] From the above, it can be seen that in order to prevent seaweed erosion in relatively shallow rocky areas in coastal areas with an average depth of 10 to 20 m, even if we consider the low margin of error, the number of units required to be laid is approximately 200 to 400 per hectare. In a demonstration experiment, it was found that if approximately 300 pieces were laid per hectare, the coastal denudation would be improved within a few months, and seaweed would be able to establish itself in the seaweed beds within about a year, which was found to be in good agreement with the above calculations.

[0101] Next, using Figure 18, we will explain how the seaweed bleaching was improved at the site where the demonstration experiment was conducted. FIG. 18 is a diagram illustrating the effect of the present invention, showing how sea denudation was improved after 300 compostable blocks 100 were laid in a predetermined sea area 200. FIG. 18 shows that 300 compostable blocks 100 were laid around the location indicated by the cross.

[0102] As shown in Figure 18, according to the system for preventing seaweed erosion, in which the compostable blocks 100 of the present invention are placed in the sea to cultivate seaweed beds, (a) before fertilization, seaweed (which look like black shadows) hardly grows in the area surrounded by the dotted line, whereas one year after fertilization, as shown in (b), seaweed (which look like black shadows) have spread throughout, indicating that the seaweed erosion has been improved.

[0103] 6. Roles and Effects of Primary and Secondary Fermentation in the Present Invention Next, in the present invention, primary fermentation and secondary fermentation are carried out separately, and the roles and effects of both will be explained using FIG. FIG. 19 is a diagram showing the roles and effects of the fermentation method used in the present invention, specifically, the roles and effects of primary fermentation and secondary fermentation. In the present invention, the primary fermentation is carried out at a relatively high temperature of 60 to 80°C, and in the secondary fermentation, the temperature raised in the primary fermentation is gradually lowered over a period of several months while fermenting in the range of 60 to 40°C, thereby increasing the mineralization rate.

[0104] In primary fermentation, for example, when a fertilizer manufacturing machine is used, the residual organic compound content quickly reaches about 40%, but thereafter there is little change. Similarly, in primary fermentation using a soil pit, the residual organic compound content quickly reaches about 40%, but thereafter there is little change. This is thought to be because aerobic microorganisms, which are active in the temperature range of 60 to 80°C, can only decompose a limited number of organic compounds, and fermentation will not progress any further if it is promoted for a longer period than necessary. If left as is, the organic compounds will remain, which could lead to harmful plankton growth if the material is laid in the ocean, or could reduce the content of necessary nutrients, reducing the effectiveness of fertilization.

[0105] Therefore, in the secondary fermentation process, the temperature raised in the primary fermentation is gradually lowered to promote the fermentation activity of microorganisms that become active under conditions different from those in the primary fermentation, while also promoting actions such as decomposing persistent high molecular weight organic matter in a lower temperature environment than in the primary fermentation and nitrifying the ammonia generated in the primary fermentation into nitric acid. This is shown by the dotted line in Figure 19, where the mineralization that had stalled in the primary fermentation progresses again, resulting in a decrease in the residual level of organic compounds.

[0106] 7. About the solidification material mixture Next, the characteristics of solidification for solidifying the secondary fermentation-completed material into a compostable block will be described with reference to Figures 20 and 21. FIG. 20 is a diagram showing the characteristics of the manufacturing method of the present invention, and shows how the solidification strength and ease of dissolving in seawater change depending on the blending ratio when magnesium oxide is blended as a solidification agent.

[0107] The research team behind this invention repeated trial and error, testing multiple solidification materials, including starch and magnesium oxide, at different blending ratios. They found that starch has a fast dissolution rate in seawater, causing all nutrients to dissolve in a relatively short period of time, whereas by adding an appropriate amount of magnesium oxide, it was possible to achieve a balance between the rate at which nutrients dissolve (degree of dissolution) and the duration of dissolution.

[0108] For example, when magnesium oxide is mixed in at a weight ratio of about 5% to the total, it solidifies to a certain degree of strength, but the rate at which nutrients dissolve (degree of melting) is fast and the duration is short, making it difficult for seaweed to settle and grow sufficiently.

[0109] On the other hand, when magnesium oxide was added at around 30%, the rate at which nutrients were dissolved was slow and the effect lasted for a long period of time, but it took too long to sufficiently increase the concentration of nutrients in the sea area where the material was laid, making it difficult for seaweed to settle and grow sufficiently. Therefore, it was found that adding magnesium oxide at a concentration of approximately 8-12% provides a good balance of sufficient nutrient dissolution speed and long-lasting effects.

[0110] Next, FIG. 21 is a diagram showing the characteristics of the manufacturing method of the present invention, and shows how the elution of nutrients changes depending on the addition ratio of magnesium oxide as a solidification material. According to Figure 21, if a solidifying agent such as magnesium oxide is not added, the block will melt quickly and the nutrients will leach out, resulting in a short-lasting effect (dotted line). On the other hand, if the magnesium oxide content is high, such as 30%, it will take too long to reach the required nutrient concentration, and the nutrients in the block will not be sufficiently leached, with many remaining in the block even after a long period of time has passed.

[0111] Therefore, by adjusting the distribution ratio and mixing magnesium oxide at around 10%, the necessary nutrient concentration can be secured in a relatively short period of time, and the blocks are gradually eroded by seawater, resulting in the dissolution of magnesium oxide, which has a long-lasting effect, promoting the establishment and growth of seaweed.

[0112] 8.Summary As described above, according to the present invention, a compostable block can be provided that is based on plant and marine materials and undergoes primary fermentation at a relatively high temperature, followed by secondary fermentation in which the temperature is gradually lowered from the primary fermentation, thereby keeping the residual level of organic compounds low and eliminating the substances that cause red tides, and that is sufficiently mineralized to be rich in nutrients. In addition, by using innovative solidification materials, it is possible to achieve both rapid elution of nutrients and long-term sustainability, thereby ensuring sufficient concentrations of nutrients over the long term and enabling seaweed to settle and grow. [Industrial Applicability]

[0113] The compostable blocks of the present invention not only have the direct effect of preventing marine erosion, but also enable the effective utilization of waste materials such as wood chips generated during lumber production and fishery processing residues. [Explanation of symbols]

[0114] 10 Fermentation site 20 Compost making machine 30 Mixing mixer 40 Press Machine 100 Compostable Blocks 200 designated sea areas

Claims

1. A method for producing compostable blocks for preventing rocky shore denudation in a predetermined area of ​​the sea, comprising: placing compostable blocks in the ocean; and utilizing nutrients eluted from the compostable blocks into the surrounding seawater. The manufacturing process of the compost, which is the raw material of the compostable block, includes the following steps: A process of mixing a wood-based material made from wood including wood chips or sawdust with seafood processing residue derived from seafood processing; A primary fermentation step in which the mixed wood-based material and the seafood processing residue are fermented while being stirred to produce a primary fermented material; A secondary fermentation process is a process for decomposing the persistent high molecular weight organic matter that was not decomposed in the primary fermentation process, in which the primary fermentation material is fermented while gradually lowering the temperature from the temperature increased in the primary fermentation process to produce a secondary fermentation material, As a manufacturing process for solidifying the generated secondary fermentation material into a compostable block, With respect to the total weight of the secondary fermentation material produced in the secondary fermentation step, an additive addition process in which 8 to 12 wt % of a solidifying agent for solidifying into a block, 20 to 25 wt % of a metal material including steel slag for adjusting the specific gravity and promoting solidification, and 0.5 to 1.0 wt % of a thickening agent including guar gum as a binder are added as additives; A step of stirring the secondary fermentation material and the additive; A step of pressing the mixture of the secondary fermentation material and the additives after the stirring into a predetermined shape or a step of filling it into a mold; A step of solidifying the mixture of the secondary fermentation material and the additives after the stirring for a predetermined period of time; A method for producing a compostable block, comprising:

2. The primary fermentation step is primary fermentation at a premises, A process of fermenting the mash above ground at a temperature of approximately 60 to 80°C for a period of approximately 2 to 3 months.

2. A method for producing the compostable block according to claim 1,

3. The primary fermentation step is a primary fermentation using a fertilizer manufacturing machine equipped with a rotation mechanism for stirring, A step of fermenting the fertilizer using the fertilizer production machine at a temperature of approximately 70 to 80 ° C for a period of approximately two weeks.

2. A method for producing the compostable block according to claim 1,

4. The secondary fermentation step In order to decompose the hardly decomposable polymer organic matter that was not decomposed in the primary fermentation, the primary fermentation material is fermented while gradually lowering the temperature from the temperature increased in the primary fermentation step to produce a secondary fermentation material, The fermentation temperature is set to be at least 10°C lower than the fermentation temperature in the primary fermentation step; 2. A method for producing the compostable block according to claim 1,

5. As the solidification material in the manufacturing process for solidifying the generated secondary fermentation material into a compostable block, Using 8 to 12% by weight of magnesium oxide based on the total weight of the secondary fermentation material produced in the secondary fermentation step and the additives; A method for producing the compostable block according to any one of claims 1 to 4, characterized by:

6. 6. The method for producing a compostable block according to claim 5, By using magnesium oxide as the solidifying material in the manufacturing process for solidifying the generated secondary fermentation material into a compostable block, The magnesium oxide reacts with water to be converted into magnesium hydroxide by a hydration reaction, and The magnesium oxide reacts with the added steel slag to promote crystalline bonding, thereby enhancing solidification; A method for producing compostable blocks, characterized by:

7. A secondary fermentation material that is a fermentation product of mixed wood chips and fishery processing residue, in which organic compounds are decomposed into inorganic nutrients; The additives include 8 to 12% by weight of a solidifying material for solidifying into a block, 20 to 25% by weight of a metal material including steel slag for adjusting the specific gravity and promoting solidification, and 0.5 to 1.0% by weight of a thickening material including guar gum as a binder, relative to the total weight including the secondary fermentation material. Compostable blocks characterized by:

8. As the solidification material for solidifying the secondary fermentation material into a compostable block, Using 8 to 12% by weight of magnesium oxide based on the total weight of the secondary fermentation material and the additive; 8. The compostable block of claim 7, wherein:

9. The magnesium hydroxide derived from the magnesium oxide is contained, and solidification is strengthened by crystalline bonding between the magnesium oxide and the added steel slag; 9. The compostable block of claim 8, wherein:

10. A seaweed bed cultivation system in which the compostable block according to any one of claims 7 to 9 is placed in a predetermined sea area to cultivate a seaweed bed.

11. A method for preventing rocky shore bleaching, comprising: placing the compostable block according to any one of claims 7 to 9 in a predetermined sea area and allowing nutrients to elute, thereby promoting the creation of a seaweed bed.

12. A method for promoting the creation of a seaweed bed by placing the compostable block according to any one of claims 7 to 9 in a predetermined sea area and eluting nutrients, This method for preventing rocky shore denudation is characterized by laying the compost-degradable blocks so that the margin, which is an index showing the ability to produce seawater containing sufficient nutrients for the growth of seaweed, is approximately 10 or more.

Images