Solids for algal field formation

Abstract

This invention provides a solid material for seaweed bed formation that is suitable for the establishment and reproduction of seaweed, by stably generating iron fulvic acid over a long period of time and supplying iron to aquatic bodies. [Solution] The solid material 1 for seaweed bed formation consists of sewage sludge char 2, large-grained steelmaking slag 3, small-grained steelmaking slag 4, and activated carbon 5 that has adsorbed fulvic acid, all solidified into a mass with cement 6. The activated carbon is formed by carbonizing and activating waste plastic or waste clothing.

Description

Technical Field

[0001] The present invention relates to a solid for forming a seaweed bed.

Background Art

[0002] In recent years, in the rocky reef and boulder areas of the coastal waters of Japan, a phenomenon called "rock burning" has occurred frequently, in which seaweed (seagrass) beds where seaweed (seagrass) grows have significantly declined and disappeared, and the reduction of coastal fishery resources such as kelp, abalone, and turban shell has become remarkable.

[0003] One of the causes of "rock burning" is that the iron content (iron ions) necessary for the growth of seaweed (seagrass) may be insufficient.

[0004] That is, the iron content (iron ions) contained in the coastal waters is supplied by the inflow of water-soluble iron humate, especially iron fulvate, generated in the humus soil of forests, from mountains to the sea together with river water. However, due to the recent deforestation, construction of sediment control dams, etc., the supply amount of iron fulvate in the coastal waters has significantly decreased, which is considered to be the cause of "rock burning".

[0005] And in the prior art, a water area environmental conservation material manufactured by mixing a fermented humic acid supply substance (for example, humus soil such as waste wood chips, fallen leaves, and sewage sludge) with an iron-containing substance (for example, steelmaking slag) is filled in a plurality of cloth bags, and those cloth bags are housed in a steel container and then submerged in the sea to continuously generate iron fulvate and supply iron ions to the water area, thereby a method of forming a seaweed bed is known (for example, Patent Document 1, etc.).

[0006] However, according to this method, since a mixture of humus soil directly mixed with steelmaking slag is filled in a cloth bag and housed in a steel container, iron fulvate elutes into the water area in a relatively short period, and iron ions cannot be stably supplied over a long period.

[0007] Furthermore, the surface of the steel container was flat and lacked the unevenness necessary for seaweed (seagrass) to attach and grow, and therefore was not suitable for the formation of seaweed beds.

[0008] Furthermore, humus contains not only humic acids such as fulvic acid, but also large amounts of organic matter that causes red tides. This organic matter flows into the water, causing red tides, which negatively impacts the formation of seaweed beds. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2016-194195 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] Therefore, the object of the present invention is to provide a solid material for seaweed bed formation that can generate iron fulvic acid over a long period of time, thereby stably supplying iron to the water body and being suitable for the establishment and propagation of seaweed (seagrass). [Means for solving the problem]

[0011] To solve the above problems, the present invention provides a solid material for forming seaweed beds, characterized in that carbonized sewage sludge (hereinafter referred to as "sewage sludge charcoal") and slag are solidified into a permeable mass with a binder.

[0012] In this case, the slag preferably consists of large-grain steelmaking slag and small-grain steelmaking slag. Furthermore, the binder is preferably cement, and more preferably the cement is blast furnace cement, permeable cement, or a combination thereof.

[0013] The solid material used for seaweed bed formation can be in the form of a lump, and its shape and size are not limited. Furthermore, the average particle size of sewage sludge and slag, as well as the mixing ratio of sewage sludge, slag, and binder, are determined according to the environment in which the solid material for seaweed bed formation is utilized. In this case, the hardness of the solid material for seaweed bed formation changes depending on the proportion of binder in the overall solid material (the higher the proportion of binder, the harder the solid material for seaweed bed formation becomes).

[0014] In the above configuration, preferably, the solid material for forming the seaweed bed further contains activated carbon on which fulvic acid has been adsorbed. Activated carbon is preferably made from materials formed by carbonizing and activating waste plastics or waste clothing.

[0015] More preferably, the solid material for seaweed bed formation further includes reinforcing members made of carbon fibers. The carbon fibers are preferably recycled carbon fibers, and the reinforcing member may be multiple carbon fibers themselves, or multiple carbon fibers may be solidified into a rod or plate shape.

[0016] Furthermore, the solid material for seaweed bed formation may also include a carbonizing agent, or carbonized waste plastic or carbonized waste clothing, or powdered carbonized seashells and / or crustaceans, or dried sewage sludge, or a combination of two or more of these. The average particle size of each of these additional materials and their weight ratio to the solid material for seaweed bed formation are determined according to the environment in which the solid material for seaweed bed formation is used.

[0017] The solid material for seaweed bed formation may, for example, have the form of gravel with an average particle size of 1 to 3 cm, or it may have the form of an artificial (seaweed) reef, and in the latter case, it is preferable that it has a tetrapod shape or a regular tetrahedron shape. [Effects of the Invention]

[0018] According to the present invention, sewage sludge and slag are solidified into a permeable mass using a binder to form a solid material for seaweed bed formation.

[0019] Sewage sludge contains humic acids such as fulvic acid and humic acid, mineral components, and organic substances. However, when sewage sludge is carbonized while controlling the temperature, most of the organic substances in the sewage sludge disappear, and sewage sludge peat containing humic acid and mineral components remains.

[0020] That is, sewage sludge peat contains humic acid and mineral components, but does not contain organic substances that cause seawater pollution such as red tides. In addition, slag contains iron and mineral components.

[0021] Thus, when the solid for seagrass bed formation is placed on the seabed, inside the solid for seagrass bed formation into which seawater has penetrated, iron humate, particularly iron fulvate, is generated from the humic acid in the sewage sludge peat and the iron in the slag, and iron (iron ions) and mineral components elute from the solid for seagrass bed formation. Moreover, there is no risk that organic substances that cause seawater pollution such as red tides will elute from the solid for seagrass bed formation.

[0022] In addition, since the sewage sludge peat and slag are solidified into a water-permeable mass using a binder, the elution of iron (iron ions) and mineral components from the solid for seagrass bed formation can be slowed down. Therefore, iron (iron ions) and mineral components can be stably supplied to the water area over a long period of time.

[0023] Furthermore, unevenness suitable for the growth of seaweed (seagrass) is formed over the entire surface of the solid for seagrass bed formation. Moreover, in this case, by changing the average particle size of each of the sewage sludge peat and slag, and the mixing ratio of the sewage sludge peat, slag, and binder, this uneven shape can be easily changed according to the utilization environment.

Brief Description of the Drawings

[0024] [Figure 1] It is a schematic cross-sectional view of a solid for seagrass bed formation according to one embodiment of the present invention. [Figure 2] It is a schematic view showing a solid for seagrass bed formation according to another embodiment of the present invention. [Figure 3] This is a schematic cross-sectional view of a solid material for seaweed bed formation according to yet another embodiment of the present invention. [Modes for carrying out the invention]

[0025] The configuration of the present invention will be described below based on preferred embodiments with reference to the attached drawings. Figure 1 is a schematic cross-sectional view of a solid material for seaweed bed formation according to one embodiment of the present invention. Referring to Figure 1, the solid material 1 for seaweed bed formation of the present invention consists of sewage sludge char 2, large-particle steelmaking slag 3, small-particle steelmaking slag 4, and activated carbon 5 that has adsorbed fulvic acid, all solidified into a permeable mass by a binder 6.

[0026] The average particle sizes of the sewage sludge 2, large-particle steelmaking slag 3, small-particle steelmaking slag 4, and activated carbon 5, as well as the mixing ratio of the sewage sludge 2, large-particle steelmaking slag 3, small-particle steelmaking slag 4, activated carbon 5, and cement 6, are determined according to the environment in which the solid material for seaweed bed formation 1 is used and are not particularly limited. However, in this embodiment, the solid material for seaweed bed formation 1 contains 15 to 20% by weight of sewage sludge 2 with a particle size of 0.5 to 1.5 mm, 5 to 10% by weight of (large-particle) steelmaking slag 3 with a particle size of 5 to 10 mm, 5 to 10% by weight of (small-particle) steelmaking slag 4 with a particle size of 0.5 to 1.5 mm, 5 to 10% by weight of activated carbon 5 with a particle size of 0.5 to 1.5 mm, and 30 to 50% by weight of cement 6.

[0027] In this embodiment, steelmaking slags 3 and 4 of different particle sizes are used, but one type of steelmaking slag with the same particle size may be used, or three or more types of steelmaking slag with different particle sizes may be used.

[0028] Furthermore, although steelmaking slag 3 and 4 are used in this embodiment, other types of slag (blast furnace slag, ore slag, castings, etc.) can be used instead of steelmaking slag 3 and 4.

[0029] Activated carbon 5 is preferably formed by carbonizing and activating waste plastic or waste clothing.

[0030] In this embodiment, cement is used as the binder 6, but the binder 6 is not particularly limited as long as it can bind the sewage sludge 2, steelmaking slag 3, 4 and activated carbon 5 together to form a permeable mass.

[0031] The cement 6 is preferably made of blast furnace cement, permeable cement, or a combination thereof. This allows for smoother leaching of nutrients (iron, minerals, etc.) from the solid material 1 for seaweed bed formation placed in the sea, and also creates an uneven surface on the surface of the solid material 1 that is more suitable for the growth of algae. When combining blast furnace cement and permeable cement, the mixing ratio is determined according to the environment in which the solid material 1 for seaweed bed formation is used.

[0032] According to the present invention, sewage sludge coal 2, steelmaking slag 3 and 4 of two different particle sizes, and activated carbon 5 that has adsorbed fulvic acid are solidified into a permeable mass 1 with cement 6 to form a solid material 1 for seaweed bed formation.

[0033] Sewage sludge contains humic acids such as fulvic acid and humic acid, mineral components (inorganic nitrogen, phosphorus, potassium, iron, silica, etc.), and organic matter. However, when sewage sludge is carbonized while controlling the temperature, most of the organic matter in the sewage sludge is eliminated, and sewage sludge charcoal is obtained in which humic acid and mineral components remain.

[0034] In other words, sewage sludge 2 contains humic acid and mineral components, but does not contain organic matter that causes seawater pollution such as red tides. In this example, sewage sludge char, which is formed by carbonizing sewage sludge at a temperature of 300-400°C or lower, is used, and in this case, the fulvic acid content in the sewage sludge char is 5-7%.

[0035] On the other hand, activated carbon formed by carbonizing and activating waste plastics or waste clothing is produced in 1,000 m³. 2 It has a large specific surface area of ​​approximately 1 / g, and furthermore, it has the characteristic of having a faster adsorption rate compared to existing activated carbons (coconut shell activated carbon, coal-based activated carbon, etc.), and therefore can efficiently adsorb a larger amount of fulvic acid.

[0036] In fact, when fulvic acid is adsorbed onto activated carbon formed from waste plastic or waste clothing, the average fulvic acid content of this activated carbon is about 20%, which is about four times the amount of fulvic acid found in sewage sludge charcoal 2.

[0037] The activated carbon 5, which has adsorbed fulvic acid, is used as needed when the supply of fulvic acid from the sewage sludge char 2 is insufficient, and is not an essential component of the solid material 1 for seaweed bed formation according to the present invention.

[0038] Thus, when the seaweed bed-forming solid material 1 is placed on the seabed, fulvic acid is generated from the fulvic acid in the sewage sludge charcoal 2 and activated carbon 5 and the iron in the steelmaking slag 3 and 4 within the seaweed bed-forming solid material 1 into which seawater has seeped, and iron (iron ions) and mineral components are leached out from the seaweed bed-forming solid material 1.

[0039] Furthermore, since the sewage sludge 2, steelmaking slag 3 and 4, and activated carbon 5 are solidified into a mass with cement 6, the leaching of iron (iron di ions) and mineral components from the solid material 1 for seaweed bed formation can be slowed down, and thus, iron (iron ions) and mineral components can be stably supplied to the water body over a long period of time.

[0040] Furthermore, since the sewage sludge 2, steelmaking slag 3, 4, and activated carbon 5 are solidified with cement 6, an uneven surface suitable for the attachment and propagation of seaweed (seagrass) is formed across the entire surface of the solid material 1 for seaweed bed formation. Moreover, in this case, the shape of this uneven surface can be easily changed according to the usage environment by changing the average particle size of each of the sewage sludge 2, steelmaking slag 3, 4, and activated carbon 5, and the mixing ratio of the sewage sludge 2, steelmaking slag 3, 4, activated carbon 5, and cement 6.

[0041] Furthermore, during the period from when seaweed (seagrass) begins to take root in the solid material 1 for seaweed bed formation until it reaches a certain size, there is a risk of damage from herbivorous fish. To prevent this, it is preferable to place the solid material 1 for seaweed bed formation on the seabed while it is contained in a burlap sack.

[0042] The solid material 1 for seaweed bed formation of the present invention may be in the form of a lump, and its shape and size are not limited. For example, as shown in Figure 2(C), the solid material 1' for seaweed bed formation may have the form of gravel (a collection of many irregularly shaped lumps) with an average particle size of 1 to 3 cm. In this case, the solid material 1' for seaweed bed formation is scattered on the seabed. This prevents mud from being stirred up by ocean currents, preventing mud from adhering to seaweed (seagrass), thus preventing the inhibition of photosynthesis in seaweed (seagrass), and also supplying iron and minerals necessary for the growth of seaweed (seagrass).

[0043] Furthermore, for example, as shown in Figure 2(A), the solid material 1' for seaweed bed formation may have the form of a tetrahedral artificial reef, or as shown in Figure 2(B), it may have the form of a tetrapod. Alternatively, the solid material 1'' for seaweed bed formation may have the form of the base portion of an offshore wind power generation device.

[0044] In the embodiment shown in Figure 2(A), the solid material 1' for seaweed bed formation has a tetrahedron shape, so it is not easily carried away by the current, and even if it is moved (rolled) by the current, the surface maintains its inclined state, making it difficult for floating sediment in the sea to accumulate on the surface. This prevents the growth of seaweed (seagrass) that has settled on the solid material 1' for seaweed bed formation from being hindered by the influence of the seabed mud.

[0045] Figure 3 is a schematic cross-sectional view of a solid material for seaweed bed formation according to yet another embodiment of the present invention. The embodiment shown in Figure 3 is an embodiment in which the structural strength of the solid material for seaweed bed formation has been increased to prevent the solid material from collapsing in a short period of time due to insufficient strength for the environment in which it is used, depending on the mixing ratio of the forming materials, compared to the embodiment shown in Figure 1. Therefore, in Figure 3, the same components as those shown in Figure 1 are given the same numbers, and their detailed explanations are omitted.

[0046] Referring to Figure 3, in this embodiment, the solid material 7 for seaweed bed formation includes a reinforcing member 8 made of carbon fiber. The carbon fibers are preferably recycled carbon fibers, and the reinforcing member 8 may be, for example, multiple carbon fibers themselves as shown in Figure 3(A), multiple carbon fibers solidified into a rod shape as shown in Figure 3(B), or multiple carbon fibers solidified into a plate shape as shown in Figure 3(C).

[0047] Furthermore, as can be seen in Figure 3(C), if the reinforcing member 8 consists of multiple carbon fibers solidified into a plate shape, it is preferable that multiple holes 8a are provided that penetrate both sides of the plate. As a result, the portion 7a of the solid material for seaweed bed formation 7 located on one side of the reinforcing member 8 and the portion 7b located on the other side of the reinforcing member 8 are firmly connected through their holes 8a, and the reinforcing member 8 and the other forming materials of the solid material for seaweed bed formation are integrated.

[0048] Carbon fibers possess properties such as no thermal shrinkage and high resistance to tension, compression, and bending. When integrated with other forming materials for seaweed bed formation, their strength is increased.

[0049] Although preferred embodiments of the present invention have been described above, it goes without saying that the configuration of the present invention is not limited to the above-described embodiments, and that those skilled in the art can devise various modifications within the scope of the configuration described in the appended claims.

[0050] For example, in the embodiment shown in Figure 1, the solid material 1 for seaweed bed formation may further include a carbonizing agent, or carbonized waste plastic, or carbonized waste clothing, or powder of carbonized seashells and / or crustaceans, or dried sewage sludge, or a combination of two or more of these. In this case, the average particle size of each of these additional materials and their weight ratio to the solid material for seaweed bed formation are determined according to the environment in which the solid material for seaweed bed formation is used.

[0051] Furthermore, dried sewage sludge contains more humic acid and mineral components than sewage sludge coal, but it also contains organic matter that can cause seawater pollution. Therefore, dried sewage sludge is used in addition when the supply of humic acid, especially fulvic acid, is insufficient with only sewage sludge char 2 and activated carbon 5. [Explanation of Symbols]

[0052] 1, 1´, 1” solid material for seaweed bed formation 2. Sewage sludge coal 3. Large-grain steelmaking slag 4. Small particle size steelmaking slag 5. Activated carbon with adsorbed fulvic acid 6. Binder (cement) 7 Solids for seaweed bed formation 7a Part located on one side of the reinforcing member 7b The portion located on the other side of the reinforcing member 8. Reinforcement members 8a hole

Claims

1. A solid material for forming seaweed beds, characterized by being made of carbonized sewage sludge and slag solidified into a permeable mass with a binder.

2. The solid material for forming seaweed beds according to claim 1, characterized in that it contains activated carbon that has adsorbed fulvic acid.

3. The solid material for forming seaweed beds according to claim 2, characterized in that the activated carbon is formed by carbonizing and activating waste plastic or waste clothing.

4. The solid material for forming seaweed beds according to claim 2, characterized in that it contains a reinforcing member made of carbon fiber.

5. The solid material for forming seaweed beds according to claim 4, characterized in that it contains a carbonizing agent.

6. The solid material for forming seaweed beds according to claim 5, characterized in that it contains carbonized waste plastic or carbonized waste clothing.

7. The solid material for forming seaweed beds according to claim 6, characterized in that it contains powder of seashells and / or carbonized crustaceans.

8. The solid material for forming seaweed beds according to claim 7, characterized in that it contains dried sewage sludge.

9. The solid material for forming seaweed beds according to claim 1, characterized in that the slag consists of large-grain steelmaking slag and small-grain steelmaking slag.

10. The solid material for forming seaweed beds according to claim 1, characterized in that the binder is cement.

11. The solid material for forming seaweed beds according to claim 10, characterized in that the cement is blast furnace cement, permeable cement, or a combination thereof.

12. A solid material for forming seaweed beds according to any one of claims 1 to 11, characterized in that it has the form of a tetrapod-shaped or regular tetrahedron-shaped artificial reef.

13. A solid material for forming seaweed beds according to any one of claims 1 to 11, characterized in that it has the form of gravel with an average particle size of 1 to 3 cm.

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