JP2023176981A - Nutrient supply material using methane fermentation digested liquid and seashell - Google Patents

Abstract

To provide a nutrient supply material capable of effectively using a methane fermentation digested liquid and seashells, stably eluting nutrient components to an oligotrophic water area while securing necessary and sufficient strength, and controlling the elution strength.SOLUTION: A nutrient supply material includes a methane fermentation digested liquid or a concentrate thereof and seashells. Furthermore, the nutrient includes at least one kind selected from a group consisting of nitrogen (N), phosphorus (P), and silicon (Si).SELECTED DRAWING: None

Description

The present invention relates to a nutrient supply material using methane-fermented digestive fluid and shells.

The amount of livestock waste generated per year in Japan is approximately 80 million tons (2020, Ministry of Agriculture, Forestry and Fisheries), and the amount of food waste is approximately 25 million tons (2018, Ministry of the Environment). The problem is that both livestock waste and food waste are produced in extremely large quantities. Specifically, in recent years, the recycling of biomass resources has become important from the perspective of carbon neutrality and SDGs (Sustainable Development Goals). Biogas power generation using methane fermentation is attracting attention because it can produce both liquid (liquid fertilizer) and reduce odor.

Digestive fluid produced as a by-product in methane fermentation plants (hereinafter referred to as methane fermentation digestive fluid) has so far been sprayed on fields and returned to farmland as liquid fertilizer.
However, methane-fermented digestive fluid is only applied to farmland in the spring, before cultivation begins, and due to recent reductions in farmland area, there is a limit to the amount of digestive fluid that farmland can accept. was there. During seasons other than spring, there is an oversupply of methane-fermenting digestive fluid, which has been treated as wastewater.
Further, as a method for treating wastewater of methane-fermented digestive juice, for example, there is a method in which a flocculant is added to the methane-fermented digestive liquid to perform solid-liquid separation, and the resulting liquid is subjected to activated sludge treatment, etc. (Patent Document 1) ). In order to perform such wastewater treatment, extra equipment and costs are required, and furthermore, the power consumption required for wastewater treatment is large, and there is a problem that the energy balance is not balanced.
Therefore, in order to achieve both biogas power generation through methane fermentation and stable processing of terrestrial biomass, there is a need to develop new uses for methane fermentation digestive fluid that can be used effectively throughout the year. .

Additionally, the amount of oyster shells generated during oyster farming is estimated to be approximately 160,000 tons annually nationwide (Ministry of Land, Infrastructure, Transport and Tourism, 1998). Oyster shells were previously used as chicken feed, but in recent years they have been replaced by calcium-based chemically synthesized feed. Therefore, the disposal of shells such as oyster shells has also become an urgent issue in countries around the world.

Furthermore, since the period of high economic growth, the number of occurrences of red tide due to eutrophication has increased in coastal areas, but as drainage regulations have been tightened, the number has decreased in recent years and water quality has improved.
On the other hand, due to a decrease in nutrient loads from rivers due to dam construction and topographical changes due to coastal land development, oligotrophication (decreased nutrient salts in seawater) is progressing, resulting in a decline in fisheries production and seaweed beds. Problems such as a decrease in As techniques for supplying nutrients to coastal areas, mitigation operations at sewage treatment plants and enclosing the surrounding area after adding nutrients to the ocean are being considered, but these methods have not been sufficiently effective because the nutrients diffuse. It has not been done.
Therefore, there is a strong need for the development of nutrient supply materials that can stably supply nutrients to coastal areas where oligotrophic conditions have progressed.

Japanese Patent Application Publication No. 2004-290921

An object of the present invention is to provide a nutrient supply material that can effectively utilize methane-fermented digestive fluid and shells.
Another object of the present invention is to provide a nutrient supply material that can stably elute nutrients into oligotrophic waters while ensuring necessary and sufficient strength, and that can control the elution rate. shall be.

As a result of extensive research in order to solve the above problems, the present inventors have discovered that using methane-fermented digestive fluid or its concentrate and shell powder as raw materials, a nutrient-supplying material made by mixing and solidifying these is used in sea water. It was discovered that when immersed in the liquid, nutrients necessary for the growth of microalgae are released in a sustained manner. The present invention was completed based on such knowledge.

That is, the present invention is as follows.
Item 1.
Nutrient supply material containing methane-fermented digestive fluid or its concentrate and shells.
Item 2.
Item 2. The nutrient supply material according to item 1, wherein the nutrient contains at least one selected from the group consisting of nitrogen (N), phosphorus (P), and silicon (Si).
Item 3.
Item 3. The nutrient supply material according to item 1 or 2, wherein the nutrient is nitrogen, and the elution of the nitrogen is controlled to 0.02 to 50 mg-N/g as ammonia nitrogen.
Item 4.
The nutrient supply material according to any one of Items 1 to 3, wherein the nutrient is nitrogen, and the elution of the nitrogen is controlled to 0.00001 to 50 mg-N/g as nitrite nitrogen.
Item 5.
The nutrient supply material according to any one of Items 1 to 4, wherein the nutrient is nitrogen, and the elution of the nitrogen is controlled to 0.02 to 50 mg-N/g as nitrate nitrogen.
Item 6.
The nutrient supply material according to any one of Items 1 to 5, wherein the nutrient is phosphorus, and the elution of the phosphorus is controlled to 0.0085 to 7.7 mg-P/g as phosphate phosphorus.
Section 7.
The nutrient supply material according to any one of Items 1 to 6, wherein the nutrient is silicon, and the elution of the silicon is controlled to 0.01 to 225 mg-Si/g as silicate silicon.
Section 8.
Item 8. The nutrient supply material according to any one of Items 1 to 7, which has a compressive strength of 15 to 90 mN/mm ² .
Item 9.
The nutrient supply material according to any one of Items 1 to 8, wherein the amount of the shellfish added to the methane-fermented digestive juice is 7.5 to 33.5%.
Item 10.
The nutrient supply material according to any one of Items 1 to 9, wherein the shell is an oyster shell.
Item 11.
A nutrient supply material containing at least methane-fermented digestive juice or its concentrate and shells as raw materials.
Item 12.
An algae growth promoting material comprising a methane fermentation digestive juice or its concentrate and a nutrient supplying material containing shells.
Item 13.
An algae growth promoting material comprising at least a methane-fermented digestive juice or its concentrate and a nutrient-supplying material containing shells as raw materials.
Section 14.
A method for producing a nutrient-supplying material containing a methane-fermented digestive juice or a concentrate thereof and a seashell, comprising the steps of: mixing the methane-fermenting digestive liquid or its concentrate and the shells to obtain a mixture; and drying the mixture.
Item 15.
Item 15. A nutrient supply material obtained by the production method according to item 14.
Section 16.
A material for controlling the growth rate of algae, comprising a nutrient supply material containing methane-fermented digestive fluid or its concentrate, and shells.
Section 17.
A material for controlling the growth rate of algae, which contains a nutrient supply material containing at least methane-fermented digestive juice or its concentrate and shells as raw materials.
Section 18.
A method for effectively utilizing methane-fermented digestive fluid and shells, comprising the steps of mixing methane-fermented digestive fluid or its concentrate and shells, and drying the resulting mixture.
Item 19.
A method for growing fish and shellfish, comprising the step of arranging a nutrient supply material containing at least methane-fermented digestive juice or its concentrate and shells as raw materials in an aquaculture cage.
Section 20.
A method for cultivating shellfish, comprising the step of disposing in a culture raft a nutrient supply material containing at least methane-fermented digestive juice or its concentrate and shells as raw materials.
Section 21.
A method of applying a nutrient-supplying material containing methane-fermented digestive fluid or its concentrate and shells to plants.
Section 22.
A method of applying to plants a nutrient supplying material containing at least methane-fermented digestive juice and shells as raw materials.
Section 23.
A method for growing a plant, comprising the step of using a nutrient supply material containing a methane-fermented digestive juice or its concentrate and a shell to a plant or soil or culture solution in which the plant grows.
Section 24.
A method for growing a plant, comprising the step of using a nutrient supply material containing at least methane-fermented digestive juice or its concentrate and shells as raw materials in a plant or the soil or culture solution in which the plant grows.
Section 25.
A method for growing agricultural products, comprising the step of arranging a nutrient supply material containing methane-fermented digestive fluid or its concentrate and shells in a plant factory.
Section 26.
A method for growing agricultural products, comprising the step of arranging in a plant factory a nutrient supply material containing at least methane-fermented digestive juice or its concentrate and shells as raw materials.

Furthermore, in the present invention, it is necessary to specify all of the ingredients and structure of the nutrient supply materials specified in the manufacturing process at present. Because it is impossible or impractically difficult to do so, it is described in terms of product-by-process claims.

According to the nutrient supply material of the present invention, it is possible to effectively utilize methane-fermented digestive juices and shells, and also to stably elute nutrients into oligotrophic waters while ensuring necessary and sufficient strength. Elution rate can be controlled. Therefore, by immersing the nutrient-supplying material of the present invention in seawater, the growth of algae is promoted, oligotrophic sea areas are fertilized, and fisheries production can be restored.

FIG. 1 is a graph showing the relationship between the amount of seashells added to the methane-fermented digestive fluid and the compressive strength of the nutrient supply material. FIG. 2 is a graph showing the relationship between the amount of shells added to the methane-fermented digestive fluid, calcium carbonate (calcite) derived from shells (symbol □), and calcium silicate (symbol ●) as a nutrient supply material. FIG. 3 is a graph showing the relationship between the amount of seashells added to the methane-fermented digestive fluid and the amount of phosphate phosphorus eluted from the nutrient supply material. FIG. 4 is a graph showing the relationship between the amount of shells added to the methane-fermented digestive fluid and the amount of ammonia nitrogen eluted from the nutrient supply material. FIG. 5 is a graph showing the relationship between the amount of shells added to the methane-fermented digestive fluid and the amount of nitrite nitrogen eluted from the nutrient supply material. FIG. 6 is a graph showing the relationship between the amount of shells added to the methane-fermented digestive fluid and the amount of nitrate nitrogen eluted from the nutrient supply material. FIG. 7 is a graph showing the relationship between the amount of shells added to the methane-fermented digestive fluid and the amount of silicic acid eluted from the nutrient supply material. FIG. 8 is a graph showing the change over time in the amount of phosphate phosphorus eluted from the nutrient supply material in which the amount of added seashells is 10%. FIG. 9 is a graph showing changes over time in the amount of ammonia nitrogen eluted from the nutrient supply material in which the amount of added seashells is 10%. FIG. 10 is a graph showing the change over time in the amount of nitrite nitrogen eluted from the nutrient supply material in which the amount of added seashells is 10%. FIG. 11 is a graph showing the change over time in the amount of nitrate nitrogen eluted from the nutrient supply material in which the amount of added seashells is 10%. FIG. 12 is a graph showing the change over time in the amount of silicic acid eluted from the nutrient supply material in which the amount of added seashells is 10%. FIG. 13 is a graph showing daily changes in chlorophyll-a concentration in natural seawater to which a nutrient-supplying material having a shell content of 10% is added, and in natural seawater without additives. FIG. 14 is a graph showing the relationship between the amount of shells added as a nutrient supply material and the specific growth rate of Skeletonema. FIG. 15 is a graph showing the relationship between the amount of nutrient supply material added to seawater, the phosphate phosphorus concentration, and the specific growth rate of Skeletonema. FIG. 16 is a graph showing daily changes in ammonia nitrogen concentration in each test section. FIG. 17 is a graph showing daily changes in phosphate phosphorus concentration in each test section. FIG. 18 is a graph showing daily changes in silicate silicon concentration in each test section. FIG. 19 is a graph showing daily changes in chlorophyll a concentration in each test section. FIG. 20 is a graph showing relative growth rates based on oyster weight in Example Section 2 and Comparative Example Section 2. FIG. 21 is a graph showing the relative growth rate of oyster shell height in Example Section 2 and Comparative Example Section 2.

Nutrient Supply Material The nutrient supply material of the present invention contains methane-fermented digestive fluid or its concentrate, and shells. The nutrient supply material of the present invention may contain at least methane-fermented digestive juice or its concentrate and shells as raw materials.
The nutrient-supplying material of the present invention refers to a material that supplies (releases) nutrients. The nutrients include at least one selected from the group consisting of nitrogen (N), phosphorus (P), and silicon (Si).
The nutrient supply material of the present invention uses methane-fermented digestive fluid, which is a natural material, and shells, which are natural materials, as raw materials, and can be said to be an environmentally friendly nutrient supply material. This makes it possible to effectively utilize methane-fermented digestive fluid and shells, which have conventionally been mostly discarded.

Methane-fermented digestive fluid or its concentrate The nutrient supply material of the present invention uses a methane-fermented digestive fluid or its concentrate as a raw material. In the present invention, "methane-fermented digestive fluid" refers to non-edible agricultural products such as livestock excrement, food processing residue, defective products generated in the food manufacturing process, leftover food, waste cooking oil, garbage, substandard onions, and tomato stems. It refers to the residue obtained after methane fermentation treatment in a biogas plant (BGP) using raw materials such as human waste, human waste, and household septic tank sludge. Methane-fermented digestive juice is also called methane-fermented sludge, or simply called digestive juice.
Here, methane fermentation is a method of decomposing organic matter using the action of microorganisms that are active without contact with air (oxygen), and is also called anaerobic fermentation because methane gas is generated through fermentation. For example, in methane fermentation of livestock excrement, in an anaerobic atmosphere, the action of anaerobic microorganisms (acid-producing bacteria and methanogens) decomposes organic matter in the material to be treated, including livestock excrement, and produces biomass containing methane gas. Generate gas. Biogas is recovered and used as fuel, etc. Digestion fluid is the residue that remains after biogas is collected.

The concentrate (concentrate of methane-fermented digestive juice) means what is obtained by concentrating the above-mentioned methane-fermented digestive juice. The term "concentrate" as used herein includes not only concentrated methane-fermented digestive juices that contain moisture (water), but also dry products in which the moisture has been completely evaporated. Here, concentration includes, for example, a method of separating the methane-fermented digestive juice into solid and liquid and concentrating the liquid part by vacuum distillation, a method of concentrating the methane-fermented digestive liquid with a membrane (e.g., membrane separation activated sludge method). (MBR), etc.), or by evaporating water at low temperatures to concentrate so that the fertilizer components remain unchanged. When drying, natural drying or forced drying using a device may be used. Examples of forced drying methods include drying methods using heating, freeze drying, blowing air, hot air, and the like.

The methane-fermented digestive juice is preferably derived from livestock excrement (eg, cow dung, pig dung, chicken dung, horse dung, etc.) from the viewpoint of easy availability of a large amount of raw material.

As the methane fermentation digestive juice, a slurry containing about 2 to 15% solids can be used. Note that the amount of solid content varies somewhat depending on the raw materials used. The methane-fermented digestive fluid contains nutrients, methanogenic bacteria, bacteria other than methanogenic bacteria, and suspended solids (SS) such as cellulose fibers.

"Nutrient" means, in seawater, nutrients necessary for the growth of algae, such as macroalgae or microalgae, especially phytoplankton or sessile microalgae (hereinafter simply referred to as "algae"). (Also referred to as nutrient salts, nutrient salts, nutrient sources, or nutrients.) On land, it refers to fertilizer components required for the growth of agricultural crops.
The nutrients need only contain at least one element selected from the group consisting of nitrogen (N), phosphorus (P), and silicon (Si), and the three elements nitrogen (N), phosphorus (P), and silicon (Si). is preferably included.

If the nutrients are in seawater, they can include iron (Fe) and the like in addition to the nitrogen (N), phosphorus (P), and silicon (Si) mentioned above.
Here, specific examples of nitrogen (N) include ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, organic nitrogen, ammonium ions, ammonia, nitrite ions, nitrate ions, and the like.
Specific examples of phosphorus (P) include phosphoric acid, phosphate phosphorus (orthophosphoric acid), phosphate ion, organic phosphorus, and the like.
Specific examples of silicon (Si) include silicates, silicon silicates, silicate ions, and the like.
On land, in addition to the above nitrogen (N), phosphorus (P), and silicon (Si), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), etc. can contain ingredients.

Methanogenic bacteria, also called methanogens, are not particularly limited as long as they include microorganisms that have the ability to generate methane from organic waste through intermediate products.

Furthermore, in the present invention, "bacteria other than methane-producing bacteria" means acid-producing bacteria, but may include bacteria that do not have acid-producing ability.
Examples of each type of microorganism include acid-producing bacteria such as Clostridium genus such as Clostridium bifermentas, and methanogens such as Methanosarcina barkeri (Methanosarcina barkeri). Examples include the genus Methanosarcina, the genus Methanothrix (Methanosaeta), and the like.

Cellulose fibers originate from livestock that eats plants (for example, dried organic matter such as rice straw, wheat straw, and sawdust; grass, etc.) and obtains them as feces.

Shells Seashells are used as raw materials for the nutrient supply material of the present invention. The shell is not particularly limited as long as it contains calcium, and examples include shells of bivalves such as oysters, scallops, clams, freshwater clams, clams, red shells, abalones, mussels, and pearl oysters; and shells of snails such as turban shells.
The shell functions as a binder to solidify the nutrient-supplying material containing the methane-fermented digestive fluid or its concentrate. In addition, shells also have the effect of reducing the bad odor of methane-fermented digestive juices or their concentrates.
Among these, oyster shells and scallop shells are preferred because they can be obtained in large quantities and at low cost. In addition, by using shells effectively, the amount of discarded shells can be reduced.
In particular, oyster shells are highly porous, have high humidity control properties, and contain calcium and magnesium, so they can be reacted with silicon components contained in methane-fermented digestive juices or their concentrates to induce cement hydration reactions. This is preferable because it induces solidification easily.

Seashells contain highly pure calcium carbonate, which is synthesized from carbon dioxide gas and calcium ions in the sea. For example, when an oyster secretes a combination of protein and lime in water, the lime content eventually combines with carbon dioxide gas in the water to synthesize an oyster shell made of carbonate lime crystals. The shell contains calcium carbonate, protein, etc.

The nutrient supply material of the present invention may contain shells as a raw material. When using seashells, the shape is not particularly limited; natural seashells may be used as they are, or the seashells may be crushed or crushed and used in the form of shell pieces, powder, granules, etc. . Shells of various shapes can be mixed and used, and it is preferable to include at least a powdered shell (shell powder) from the viewpoint of ease of hardening.
Moreover, since the nutrient supply material of the present invention only needs to contain shells as a raw material, calcium compounds derived from shells (for example, shell calcined calcium, etc.) can also be used.

For example, when using powdered seashells (shell powder), the average particle size thereof is, for example, 10 mm or less, preferably 5 mm or less, more preferably 3 mm or less, and the lower limit is, for example, 1 nm or more, Preferably it is 10 nm or more, more preferably 100 nm or more. In addition, when using particles having an average particle diameter exceeding 10 mm, shell pieces or granular shells may be used.

The amount of seashells to be added is not particularly limited as long as it can solidify the methane-fermented digestive fluid or its concentrate.

For example, when blending methane-fermented digestive fluid and shells, the methane-fermented digestive fluid and shells are preferably blended in a volume:mass ratio of 1:0.075 to 0.33. That is, the amount of shells added to the methane-fermented digestive juice is expressed by the following formula (1).
Equation (1): Numerical value (%) expressing the amount of added shells to the volume of methane-fermented digestive juice as a percentage = [mass of shells (g) / volume of methane-fermented digestive juice (mL)] x 100
The numerical value (%) expressed as a percentage of the amount of shells added to the volume of the methane-fermented digestive fluid is hereinafter also referred to as the "addition amount (%)" of shells.
The amount of seashell added is usually 7.5 to 33.5%, preferably 8 to 25%, and more preferably 9 to 11%.
Specifically, the addition amount of shells of 7.5 to 33.5% means that 0.075 to 0.33 g of shells are used per 1 mL of methane-fermented digestive fluid.

For example, when blending a concentrate of methane-fermented digestive juice and shells, the concentrate of methane-fermented digestive juice and the shells may be blended in a volume:mass ratio of 1:0.075 to 3.3. is preferred. The numerical value (%) expressed as a percentage of the amount of seashells added to the volume of the concentrate of methane fermentation digestive juice (the amount of seashells added (%)) is 7.5 to 330%, preferably 8 to 250%, More preferably 10% to 100%.
Specifically, the addition amount of shells of 7.5 to 330% means that 0.075 to 3.3 g of shells are used per 1 mL of concentrated methane fermentation digestive fluid.

The nutrient supply material of the present invention may contain other raw materials other than methane-fermented digestive fluid or its concentrate and shells. Examples of such other raw materials include lignin, quartz sand, cellulose, bentonite, and the like. By blending these other raw materials, a stronger nutrient supplying material can be obtained.

Method for producing the nutrient supply material of the present invention The method for producing the nutrient supply material of the present invention is not particularly limited. ), a step of drying the obtained mixture (hereinafter referred to as "drying step"), etc. If the methane-fermented digestive juice concentrate contains little water and is close to or dry, it may further include a step of adding moisture. The amount of water may be approximately the same as the mass of the shell.

The mixing process is not particularly limited; (1) a method of stirring and mixing the entire amount of shells and the entire amount of methane-fermented digestive juice or its concentrate from the beginning; (2) a method of mixing the whole amount of shells with methane-fermented digestive juice or its concentrate; (2) adding methane-fermented digestive juice or its concentrate to the shells (3) A method of gradually adding seashells to methane-fermented digestive juice or its concentrate and stirring and mixing; (4) A semi-dried paste of seashells and methane-fermented digestive liquid. Examples include a method of stirring and mixing with a concentrate of
By mixing the methane-fermented digestive fluid or its concentrate with the shell, the silicic acid in the methane-fermented digestive fluid or its concentrate reacts with the calcium in the shell to produce calcium silicate, which solidifies.
As the shell, it is preferable to use at least a powdered shell (shell powder) from the viewpoint of ease of hardening. Note that it is also possible to crush the shells during the mixing process.
Additionally, nutrients, shells, shell powder, etc. may be added during the mixing process.

The drying process is not particularly limited, and examples include heat drying, vacuum drying, and the like.

The temperature for heat drying is usually 30°C to 100°C, preferably 35°C to 70°C, more preferably 40°C to 50°C.
The heating drying time is not particularly limited as long as water evaporates, and is usually 1 to 168 hours, preferably 1 to 120 hours, and more preferably 24 to 72 hours.

The method of vacuum drying is not particularly limited, and for example, vacuum infrared (IR) drying, freeze drying, vacuum drying, etc. can be used.
The degree of vacuum is not particularly limited, and includes, for example, a reduced pressure condition of 0 to 90 kPa.
The temperature for vacuum drying is usually 0°C to 100°C, preferably 35°C to 70°C, more preferably 40°C to 50°C. In freeze-drying, the temperature is usually -80°C to -30°C, preferably -60°C to -30°C, more preferably -50°C to -40°C.
The vacuum drying time is not particularly limited as long as water evaporates, and is usually 1 to 168 hours, preferably 1 to 120 hours, and more preferably 24 to 72 hours.

The hydration step can be employed when formulating a concentrate of methane-fermented digestive fluid, ie, to form a solid formulation. Among the manufacturing methods of the nutrient supply material of the present invention, the manufacturing method including a moisture imparting step includes, for example, (1) a step of stirring and mixing solid methane-fermented digestive fluid concentrate and shells as raw materials; A manufacturing method for forming a solid preparation through a step of adding moisture to the obtained mixture and a step of drying; (2) a step of adding moisture to a solid concentrate of methane-fermented digestive fluid as a raw material; Examples include a manufacturing method in which a solid preparation is prepared through a step of stirring and mixing the obtained methane-fermented digestive fluid with shells and a step of drying.

When methane-fermented digestive fluid or its concentrate is mixed with shells, the silicic acid in the methane-fermented digestive fluid or its concentrate reacts with the calcium in the shells to produce calcium silicate, resulting in solidification. Nutrient supply material can be obtained by In this way, by using only two types of methane-fermented digestive fluid or its concentrate and shells, it is possible to obtain a solid nutrient-supplying material having a certain degree of compressive strength without adding any other raw materials. Therefore, a nutrient supply material containing only methane-fermented digestive fluid or its concentrate and shells as raw materials can be easily produced at low cost.

The shape, size, etc. of the nutrient supply material of the present invention can be appropriately set depending on the purpose of using the nutrient supply material, the place where it is placed, etc. Examples of the shape include tablets and pellets. As for the size, for example, in the case of a tablet, the diameter is about 50 to 80 mm, and the height is about 35 to 45 mm.

The nutrient supply material of the present invention is made by blending at least methane-fermented digestive juice or its concentrate and shells as raw materials, and by mixing and solidifying these to take a solid form, Nutrients in the concentrate can be stably retained in the nutrient supply material.

The nutrient supply material of the present invention can control the amount of nutrient elution.

The larger the elution amount of ammonia nitrogen, the better. The general elution amount of ammonia nitrogen is about 0.02 to 50 mg-N/g, preferably about 0.04 to 25 mg-N/g, more preferably 0.1 to 20 mg-N/g. It is about g. Ammonia nitrogen is, for example, a nutrient for microalgae (phytoplankton, etc.) and macroalgae, and is said to be necessary for the growth of microalgae (phytoplankton, etc.) and macroalgae.

It is preferable that the elution amount of nitrite nitrogen is larger. The general elution amount of nitrite nitrogen is about 0.00001 to 50 mg-N/g, preferably about 0.01 to 25 mg-N/g, more preferably 0.1 to 20 mg-N /g.

It is preferable that the elution amount of nitrate nitrogen be larger. The general elution amount of nitrate nitrogen is about 0.02 to 50 mg-N/g, preferably about 0.04 to 25 mg-N/g, more preferably 0.1 to 20 mg-N/g. It is about g. Nitrate nitrogen serves as a nutrient for microalgae (phytoplankton, etc.) and macroalgae, and is said to be necessary for the growth of microalgae (phytoplankton, etc.) and macroalgae.

The larger the elution amount of phosphate phosphorus, the better. The general elution amount of phosphate phosphorus is about 0.0085 to 7.7 mg-P/g, preferably about 0.01 to 4.1 mg-P/g, more preferably 0.05 mg-P/g. ~3.6mg-P/g.

It is preferable that the elution amount of silicon silicate is larger. The general elution amount of silicon silicate is about 0.01 to 225 mg-Si/g, preferably about 0.02 to 120 mg-Si/g, more preferably 0.03 to 100 mg-Si /g.

The compressive strength of the nutrient supply material of the present invention is usually about 15 to 90 mN/mm ² , preferably about 17 to 75 mN/mm ² , and more preferably about 20 to 65 mN/mm ² . By having such compressive strength, nutrients can be eluted little by little without breaking when immersed in water. Note that it is possible to deviate from these ranges as long as the amount of nutrients supplied increases.

The nutrient supply material of the present invention can reduce the odor (malodor) of methane-fermented digestive fluid or its concentrate due to the action of the shell.
Examples of the odor of methane-fermented digestive fluid or its concentrate include ammonia odor, microbial odor, hydrogen sulfide odor, fatty acid odor, and the like.

There is no particular limitation on the location where the nutrient supply material is placed, and examples thereof include ocean areas, freshwater areas (rivers, ponds, lakes, etc.), brackish areas (estuaries), land, and the like.
Nutrient supply materials used in sea areas, freshwater areas, and brackish water areas can slowly release nutrients such as nitrogen (N), phosphorus (P), and silicon (Si) by immersing them in water. can. When used in a sea area, the above-mentioned nutrients can be referred to as nutrient salts or nutrient salts. Nutrient supply materials used in ocean areas can be referred to as fertilizing materials or fertilizing materials.

By immersing the nutrient supply material of the present invention in seawater, nutrients can be eluted in a sustained manner. As a result, the growth rate of algae, especially microalgae (phytoplankton) that is food for fish and shellfish, can be promoted, which in turn solves the problem of oligotrophy in marine organisms, such as a decrease in fish and shellfish. It is expected that fishery production will increase. In addition, the supply of nutrients to seawater prevents discoloration of seaweed, seaweed, etc., and promotes the growth of macroalgae, which can be expected to attract fish.

The nutrients include at least one species selected from the group consisting of nitrogen (N), phosphorus (P), and silicon (Si), and specifically include ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, and phosphate nitrogen. Examples include phosphorus, silicate silicon, and the like.

Algae include microalgae and macroalgae.
Microalgae are phytoplankton found in water such as freshwater, seawater, and sediment.
Phytoplankton is not particularly limited and includes, for example, Amphiprora, Amphora, Chaetoceros, Cyclotella, Fragilaria, Fragilaropsis, and H. antzschia), Navicula ), Nitzschia, Phaeodactylum, Skeletonema, and Thalassiosira.
Examples of macroalgae include seaweeds such as kelp, wakame, and nori.

Application of the nutrient supply material of the present invention The nutrient supply material of the present invention can promote the growth of algae such as microalgae and macroalgae, and therefore functions as an algae growth promoter. As a result, the growth of fish and shellfish that feed on microalgae can be promoted.
Furthermore, the nutrient supply material of the present invention can control the growth rate of algae such as microalgae and macroalgae, and thus functions as a material for controlling the growth rate of algae.
The nutrient-supplying material of the present invention can promote the growth of, for example, bivalves such as oysters, scallops, and clams; shellfish such as snails such as turban shells; and fish that prey on phytoplankton in marine areas.
In addition, in freshwater or brackish water, it is possible to promote the growth of bivalves such as freshwater clams and fish that prey on phytoplankton. That is, the nutrient supply material of the present invention can be used as a growth material for the above-mentioned algae and shellfish. Growing can also be called rearing.

Examples of methods for applying the nutrient supply material of the present invention at sea include hanging it in a fish culture cage; hanging it in a shellfish culture raft; and installing it on the seabed.
The nutrient supply material of the present invention can control the elution of nutrients, so by installing the nutrient supply material of the present invention in the aquaculture cage, it becomes possible to control the nutrient salts in the aquaculture cage. . This will promote the use of ICT (Information and Communication Technology) in the fisheries sector, such as smart fishing.

Examples of methods for applying the nutrient supply material of the present invention on land include adding it to land-based aquaculture farms.
In this way, the nutrient supply material of the present invention can be used in fish and shellfish farming.

Moreover, the nutrient supply material of the present invention can also be used by installing it in an artificial fishing reef made of concrete blocks, for example. Nutrients (nutrient salts) are eluted from nutrient supply materials installed on artificial fishing reefs and remain in the water area, allowing algae such as microalgae (phytoplankton) to proliferate in seawater. Furthermore, macroalgae flourish on the bottom of the water body, small fish gather to eat the macroalgae, and large fish gather to eat the small fish, creating a habitat or feeding area for fish.

Nutrient supply materials used on land (soil) can be used for cultivation in the same way as regular fertilizers. When used on land, the nutrients can be referred to as fertilizer components. Nutrient supply materials used on land can be referred to as fertilizer compositions.

The nutrient supply material of the present invention can be used as a fertilizer, especially a slow-release fertilizer, in terrestrial agriculture. This was achieved by mixing and solidifying methane-fermented digestive fluid and shells, which had previously been available only as a quick-acting fertilizer. Further, by using the nutrient supply material of the present invention, it is also possible to supply nutrients to a plant factory.

Method for Effectively Utilizing Methane-Fermented Digestive Juice and Shells The nutrient supply material of the present invention can effectively utilize methane-fermented digestive juices and shells, which have been problematic in their usage.
The method for effectively utilizing methane-fermented digestive juice and shells of the present invention includes a step of mixing methane-fermented digestive juice or its concentrate and shells, and a step of drying the resulting mixture.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the technical scope of the present invention is not limited to these examples.

Example 1
0.67 g (oyster shell powder (w) : Digestive fluid (v) = 1:3, amount of oyster shell powder added: 33.5%), 0.5 g (oyster shell powder (w): digestive fluid (v) = 1:4, addition of oyster shell powder Amount: 25%), 0.4g (oyster shell powder (w):digestive fluid (v) = 1:5, amount of oyster shell powder added: 20%), 0.2g (oyster shell powder (w):digestive fluid) Liquid (v) = 1:10, amount of oyster shell powder added: 10%), 0.15 g (oyster shell powder (w):digestive fluid (v) = 1:13, amount of oyster shell powder added: 7. 5%), 0.1 g (oyster shell powder (w): digestive fluid (v) = 1:20, amount of oyster shell powder added: 5%), and 0.05 g (oyster shell powder (w): digestive fluid (v) = 1:40, amount of oyster shell powder added: 2.5%) and mixed, or without adding oyster shell powder (amount of oyster shell powder added: 0%), a silicone mold It was poured into a frame (length: 16 mm, width: 16 mm, height: 16 mm) and dried in a dryer at 50°C until the water evaporated and solidified, producing nutrient supply materials (samples A to H). The size of the produced nutrient supply material was 16 mm in length, 16 mm in width, and 1.3 to 4.3 mm in height.

In addition, the total nitrogen and dissolved total nitrogen of the digestive fluid obtained from the above-mentioned livestock-based methane fermentation facility used as raw materials were measured using a portable spectrophotometer (DR1900 manufactured by HACH) after thermal decomposition treatment (DRB200 manufactured by HACH). It was measured by the chromotrope method. Total phosphorus and dissolved total phosphorus were measured by the molybdenum blue method using a portable spectrophotometer (DR1900, manufactured by HACH) after thermal decomposition treatment (DRB200, manufactured by HACH). Ammonia nitrogen was measured by salicylic acid indophenol spectrophotometry using a portable spectrophotometer (DR1900 manufactured by HACH). Nitrate nitrogen was determined by naphthylethylenediamine spectrophotometry using a flow analyzer (Kyoritsu Rikagaku Kenkyusho), nitrite nitrogen was determined by naphthylethylenediamine spectrophotometry using a flow analyzer (Kyoritsu Rikagaku Kenkyusho), and phosphate was determined by naphthylethylenediamine spectrophotometry using a flow analyzer (Kyoritsu Rikagaku Kenkyusho). Each was measured by molybdenum blue spectrophotometry using a flow analyzer (Kyoritsu Rikagaku Kenkyusho).
As a result, the digestive fluid contained total nitrogen (2650 mg/L), total phosphorus (717 mg/L), dissolved total nitrogen (1100 mg/L), dissolved total phosphorus (380 mg/L), and ammonia nitrogen: 1029 mg/L. ), nitrite nitrogen (0.89 mg/L), nitrate nitrogen (less than 1.3 mg/L), and phosphate phosphorus (157 mg/L).

Test Example 1 (Relationship between the amount of seashells added to methane fermentation digestive fluid and the compressive strength of the nutrient supply material)
The obtained samples A to H (all thicknesses are within the range of 1.3 to 4.3 mm) were easily compressed by attaching the A-2 flat attachment to a digital force gauge (DST-500N: manufactured by Imada). The strength was measured. The average value of the numerical values measured four times each was defined as the compressive strength, and is shown in Table 1 below. Further, FIG. 1 shows a graph showing the relationship between the amount of shells added to the methane-fermented digestive juice and the compressive strength of the nutrient supply material. SD means standard deviation.

<Consideration>
From Table 1 and FIG. 1, it was found that as the amount of added seashells increased, the compressive strength increased. This result shows that calcium from the shells reacted with silicon from the methane-fermented digestive fluid, and that the shell powder itself functioned as an aggregate.

Further, among the above samples, for example, regarding the component concentration (%) of the above sample D, elements other than nitrogen were quantified using a wavelength dispersive X-ray fluorescence analyzer (Supermini 200: manufactured by Rigaku). The nitrogen concentration was calculated from the total nitrogen concentration of the oyster shell and the methane-fermented digestive fluid.
As a result, sample D contained nitrogen (2.6%), sodium (0.632%), magnesium (0.48%), aluminum (0.195%), silicon (1.05%), phosphorus (0.435%), sulfur (0.36%), It contained chlorine (1.56%), potassium (1.78%), calcium (28.5%), manganese (0.0304%), iron (0.147%), zinc (0.0174%), etc.

Example 2
In a disposable cup with a capacity of 50 mL, 1 g of oyster shell powder (Sunlime (registered trademark) (particle size less than 1.6 mm): manufactured by Maruei Co., Ltd.) was added to a methane fermentation facility (using livestock waste, etc. in Kobe City, Hyogo Prefecture). 4 mL (amount of oyster shell powder added: 25%), 6 mL (amount of oyster shell powder added: approximately 17%), 8 mL (amount of oyster shell powder added: approximately 13%) , or 10 mL (amount of oyster shell powder added: 10%) was added and mixed.
Thereafter, each cup was dried in a dryer at 45 to 50° C. for about 7 to 14 days until the water evaporated and solidified, producing Samples 1 to 4 (moisture content: 75 to 90%).

Test Example 2 (Relationship between the amount of seashells added to methane fermentation digestive juice, calcium carbonate (calcite) derived from seashells, and calcium silicate as a nutrient supply material)
Chemical morphology analysis was conducted using X-ray absorption fine structure analysis for Samples 1 to 4 with different amounts of shells added and shells to which methane-fermented digestive fluid was not added (Sample 5). The results are shown in Table 2 and FIG.

From Table 2 and FIG. 2, when the amount of added seashells was increased, the composition ratio of calcium silicate in the nutrient supply material increased. This revealed that silicic acid derived from methane-fermented digestive juices and calcium derived from shells reacted to produce calcium silicate, which solidified.

Test Example 3 (Relationship between the amount of shells added to methane fermentation digestive fluid and the amount of nutrient salts eluted)
Put 0.4 g of each of Samples 1 to 4 prepared in Example 2 into a 100 mL polybottle, dispense 100 mL of artificial seawater (Marine Art SF-1: manufactured by Osaka Yaken, 30 psu, pH 8.4), and rotate at 100 rpm. It was shaken at 25°C for 7 days.
After 7 days, the pH of the artificial seawater was measured using a compact pH meter (LAQUA twin: manufactured by Horiba, Ltd.), and the artificial seawater was filtered with a 0.45 μm syringe filter. Nitrate nitrogen (naphthylethylenediamine spectrophotometry using a flow analyzer), Nitrite nitrogen (naphthylethylenediamine spectrophotometry using a flow analyzer), Phosphorus (molybdenum blue spectrophotometry using a flow analyzer) , and silicon silicate (molybdenum blue spectrophotometry) were measured. The relationship between the amount of added seashells and the amount of various nutrients eluted from the nutrient supply material is shown in Tables 3 to 7 and Figures 3 to 7 below.

<Consideration>
From Table 3, Figure 3, Table 4, Figure 4, Table 7, and Figure 7, the smaller the amount of phosphoric acid, ammonia nitrogen, and silicic acid added to the shell, the higher the content of methane-fermented digestive fluid. The amount of elution was larger. This is because phosphoric acid, ammonia nitrogen, and silicic acid are contained in large amounts in methane fermentation digestive fluid.
On the other hand, as shown in Table 5, FIG. 5, Table 6, and FIG. 6, the amount of nitrite nitrogen and nitrate nitrogen eluted from the nutrient supply material increased as the amount of added shells increased. This is because the origin of nitrite nitrogen and nitrate nitrogen is thought to be the nitrification of nitrogen derived from protein (conchiolin) in shells (oyster shells).
However, the amount of dissolved inorganic nitrogen (sum of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen) eluted was the largest in sample 4 (shell addition amount: 10%).
Furthermore, the pH after the test was in the range of 7.8 to 7.9 for all samples, which was not different from the pH of seawater. As described above, even when the nutrient supply material of the present invention is put into the sea, there is no change in the pH of the seawater, so it can be said to be an environmentally friendly material.

From the results of Test Example 3, Sample 4 in which the amount of seashell added was 10% had the highest elution amounts of phosphoric acid, ammonia nitrogen, and silicate silicon. Therefore, subsequent tests were conducted using a nutrient supply material containing 10% of seashells.

Test Example 4 (Change in nutrient salt elution over time from a nutrient supply material containing 10% seashells)
2 g of sample 4 (nutrient supply material containing 10% seashells) prepared in Example 2 was placed in a 500 mL polycarbonate flask, and artificial seawater (Marine Art SF-1, manufactured by Osaka Yaken) was added in advance to 30 psu, pH 8. 4) was dispensed and shaken at 100 rpm and 25°C.
After sampling artificial seawater over a period of time and filtering it with a 0.45 μm syringe filter, the filtrate was analyzed for ammonia nitrogen (salicylic acid indophenol spectrophotometry) and nitrate nitrogen (naphthylethylenediamine spectrophotometry using a flow analyzer). ), nitrite nitrogen (naphthylethylenediamine spectrophotometry using a flow analyzer), phosphorus phosphate (molybdenum blue spectrophotometry using a flow analyzer), and silicon silicate (molybdenum blue spectrophotometry) were measured. .
After 7 days, the pH of the artificial seawater was measured using a compact pH meter (LAQUA twin: manufactured by Horiba, Ltd.).
In addition, a similar test was conducted using a plot to which no nutrient supply material was added as a comparative sample plot. Table 8 and Figures 8 to 12 show the elution behavior of various nutrients from the nutrient supply materials.

<Consideration>
From Table 8, Figure 8, Figure 9, and Figure 12, phosphoric acid, ammonia nitrogen, and silicic acid were significantly eluted within 7 days from the start of the test, and phosphoric acid and ammonia nitrogen were eluted within 14 days from the start of the test. equilibrium was reached.
On the other hand, when comparing the elution amount of dissolved inorganic nitrogen (ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen) from FIGS. 9, 10, and 11, it is found that nitrite nitrogen , and the elution amount of nitrate nitrogen was small. Since ammonia nitrogen can be used directly after being taken up by phytoplankton, it can be said that it is preferable that the main composition of dissolved inorganic nitrogen is ammonia nitrogen from the viewpoint of fertilizing oligotrophic sea areas. Additionally, ammonia nitrogen, which is normally unstable in methane-fermented digestive juices, was eluted from the nutrient supply material, indicating that ammonia nitrogen could be stably retained in the nutrient supply material.

Test Example 5 (Microalgae growth test using a nutrient supply material containing 10% shells)
0.6 g of sample 4 (nutrient supply material containing 10% seashells) prepared in Example 2 was placed in a 300 mL polystyrene cell culture flask, and 150 mL of natural seawater collected in Akitsu-cho, Higashihiroshima City, Hiroshima Prefecture was added. was dispensed and cultured at 25° C. at a light intensity of 100 μmol·s/m ² in an artificial climate chamber.
Observation using an optical microscope revealed that the dominant species of phytoplankton in natural seawater were Skeletonema, Nitzschia, and Navicula.
Natural seawater was sampled over time, and the fluorescence intensity was measured using a fluorometer (Trilogy: manufactured by TURNER) to determine the in vivo chlorophyll a concentration.
In addition, the maximum number of cells was determined from a calibration curve prepared in advance showing the relationship between the fluorescence intensity and the number of cells counted under a microscope. In addition, a test plot to which the nutrient supply material of the present invention was not added was used as a comparative sample plot, and a similar test was conducted. Table 9 and FIG. 13 show the results of daily changes in chlorophyll a concentration in natural seawater.

<Consideration>
The chlorophyll-a concentration in natural seawater at the start of the test was 0.35 μg/L, but increased to 42.91 μg/L after 6 days in the nutrient supply material addition group of the present invention. On the other hand, in the comparative example area (the area without the addition of the nutrient supply material of the present invention), the chlorophyll a concentration reached the maximum of 12.98 μg/L after 6 days.
Furthermore, the maximum cell density of phytoplankton in the nutrient supply material added area of the present invention was 3.8 x 10 ⁷ cells/L, and the maximum cell density of phytoplankton in the comparative example area was 1.7 x 10 ⁶ cells/L. /L. This shows that when the nutrient supplying material of the present invention was added, the number of phytoplankton cells increased by 22 times compared to the comparative example plot to which no nutrient supplying material was added.
These results revealed that the growth of phytoplankton was promoted using the nutrient salts eluted from the nutrient supply material of the present invention. In addition, the chlorophyll a concentration decreased from the 8th day onwards in the nutrient supply material addition area of the present invention, and from the 6th day onwards in the comparative example area. This was thought to be because natural seawater was used in the test, so zooplankton that prey on phytoplankton was also present in the culture vessel, and the phytoplankton were eaten by the proliferation of zooplankton.

Test Example 6 (Control of microalgae proliferation using the nutrient supply material of the present invention)
(1) Relationship between the amount of shells added to the methane-fermented digestive juice and the growth rate of microalgae. Based on the results of the nutrient requirement test in Reference 1 (Nishijima et al. (1990) Water Pollution Research 13, 173-179), we calculated the specific growth rate of Skeletonema, a common diatom that lives in coastal areas. , calculated using the Michaelis-Menten equation expressed by the following equation (2).
Formula (2): μ=μmax×C/(Ks+C)
(In the formula:
μ: specific growth rate (d ⁻¹ );
Ks: half-saturation constant (mg-PL ⁻¹ )=0.03;
μmax: maximum specific growth rate (d ⁻¹ ) = 0.78;
C: Phosphate concentration (mg-PL ^-1 ))

In addition, regarding the nutrient supply material of the present invention in which the amount of added seashells is 10%, the amount of phosphorus in the liquid phase after 7 days when the amount of the nutrient supply material of the present invention added to seawater is varied. Theoretical concentrations were estimated from Test Example 3, and the specific growth rate of Skeletonema was calculated for these concentrations based on equation (2). The results are shown in Table 10. Table 10 and FIG. 14 show the theoretically calculated values of the specific growth rate of Skeletonema due to the nutrient salts eluted from the nutrient supply materials with varying amounts of added shells.

<Consideration>
In Test Example 3, the result was that the amount of nutrient salts eluted was greater when the amount of added seashells was smaller. In all samples 1 to 4), the specific growth rate of Skeletonema was 0.74 to 0.77 d ^-1 , and almost the maximum growth rate was obtained. From these results, it was found that nutrient supply materials containing 10 to 25% shells do not provide the nutrients necessary for Skeletonema to proliferate under conditions where the amount of nutrient supply material added to seawater is 4 g/L. It was found that it can be eluted.

(2) Relationship between the amount of nutrient supply material added and the growth rate of microalgae In order to control the growth rate of microalgae, it is possible to change the amount of nutrient supply material added to seawater.
The specific growth rate of Skeletonema was calculated from the theoretical elution amount of phosphate phosphorus when the amount added to seawater was varied for a nutrient supply material with a shell addition amount of 10%. The results are shown in FIG.

<Consideration>
When no nutrient-supplying material is added to seawater, the specific growth rate of Skeletonema is 0.062 d ^-1 , and almost no microalgae grows. When a nutrient supply material containing 10% shell addition was added at a rate of 0.4 g/L, the specific growth rate increased to 0.65 d ^-1 (approximately 10 times the rate when no nutrient supply material was added). Furthermore, when a nutrient supply material containing 10% of shells was added at a rate of 4 g/L, the specific growth rate increased to 0.76 d ^-1 , almost reaching the maximum growth rate.
These results revealed that the growth rate of microalgae can be controlled by changing the amount of nutrient supply material added to seawater.

Example 3
600 mL of methane-fermented digestive liquid from livestock waste in Kobe city and 60 g of oyster shell powder (Sunlime (registered trademark) (particle size less than 1.6 mm) manufactured by Maruei Co., Ltd.) were placed in a 700 mL circular disposable cup. The mixture was mixed and water was evaporated in a dryer at 50°C to produce a nutrient supply material.
In addition, as a comparison sample for the comparative example, 600 mL of pure water and 60 g of blast furnace cement type B were mixed in a 700 mL circular disposable cup, and the water was evaporated in a dryer at 50°C. A sample was prepared.

Test Example 6 (Oyster growth test using the nutrient supply material of the present invention)
We verified whether oysters could grow with the nutrient salts leached from the nutrient supply materials.
Natural seawater from Takehara City, Hiroshima Prefecture was sand-filtered into a 40 cm x 30 cm x 20 cm (24 L) aquarium, and the water was constantly poured into the water tank at a seawater exchange rate of 2 rotations/day. In the example area, three nutrient supply materials manufactured in Example 3 were installed at the bottom of the aquarium. In the comparative example area, three comparative samples were placed at the bottom of the aquarium. Furthermore, for the example plots and comparative example plots, a test plot was prepared in which 10 first-age oysters from Hiroshima Prefecture were introduced, and a test plot was prepared in which no oysters were introduced. Details of the test area are as follows.

- Example area 1: Nutrient supply materials - Example area 2: Nutrient supply materials + oysters - Comparative example area 1: Comparative sample - Comparative example area 2: Comparative sample + oysters

Each experiment was performed in triplicate. From the third week after the start of the experiment, it was predicted that the dissolved oxygen concentration in the aquarium would become insufficient as the temperature rose, so aeration was performed using an air stone. Furthermore, three nutrient supply materials or comparison samples were added to each aquarium five weeks after the start of the experiment.
Periodically, the salinity and temperature of the water directly above the water are measured, and after filtering with a 0.45 μm syringe filter, dissolved phosphate ions and nitrate ions are analyzed using flow injection analysis (flow analyzer: Kyoritsu Physical and Chemical Research Institute). , ammonium ions were measured by spectrophotometry using a modified salicylic acid method (DR 1900: HACH), and nitrite ions were measured by naphthylethylenediamine spectrophotometry (UV-2600: Shimadzu Corporation). In addition, 500 mL of the water immediately above the filter was filtered using glass fiber filter paper (GF/F: Whatman) to capture chlorophyll, and after extraction with acetone in a cool and dark place, the chlorophyll a concentration (Trilogy: Turner designs) was measured. The length of the oyster shell and the height of the oyster shell were measured using calipers. In addition, the mass of the oyster was measured after removing algae attached to the oyster shell with a scrubbing brush.

Table 11 and FIG. 16 show the daily changes in ammonia nitrogen concentration in each test plot.

From Table 11 and FIG. 16, the ammonia nitrogen concentration was higher in Example Sections 1 and 2 than in Comparative Example Sections 1 and 2. On the 34th day, algae grew in the aquarium, and it was thought that ammonia nitrogen was used for the growth of algae and was depleted. After that, when the nutrient supply material was added, on the 48th day, the ammonia nitrogen concentration was again higher in Example plots 1 and 2 than in Comparative example plots 1 and 2. From the above, it is thought that ammonia nitrogen was eluted from the nutrient supply material and increased the ammonia nitrogen concentration in the seawater in the aquarium.
Although data is not shown, in Example Sections 1 and 2, it was confirmed that nitrate nitrogen and nitrite nitrogen were eluted from the nutrient supply materials.

Next, Table 12 and FIG. 17 show the daily changes in phosphate phosphorus concentration in each test group.

From Table 12 and FIG. 17, the concentration of phosphate phosphorus was higher in Example Sections 1 and 2 than in Comparative Example Sections 1 and 2 throughout the test period. From the above, it is thought that phosphate phosphorus was eluted from the nutrient supply material and increased the phosphate phosphorus concentration in the seawater in the aquarium.

Next, Table 13 and FIG. 18 show the daily changes in the silicon silicate concentration in each test group.

From Table 13 and FIG. 18, the concentration of silicon silicate was higher in Example Sections 1 and 2 than in Comparative Example Sections 1 and 2 throughout the test period. From the above, it is considered that silicic acid silicon was eluted from the nutrient supply material and increased the silicic acid silicon concentration in the seawater in the aquarium.

Table 14 and FIG. 19 show the daily changes in chlorophyll a concentration in each test section.

From Table 14 and FIG. 19, throughout the test period, the chlorophyll a concentration was higher in Example sections 1 and 2 than in Comparative example sections 1 and 2. This indicates that phytoplankton multiplied using the nutrient salts eluted from the nutrient supply materials.

The weight-based relative growth rate of oysters for 91 days from the start of the experiment is shown in Table 15 and FIG. 20, and the relative growth rate of oyster shell height is shown in Table 16 and FIG. 21.

From Tables 15 to 16 and Figures 20 to 21, an increase in the weight of oysters and the height of oyster shells was observed in Example Section 2 compared to Comparative Example Section 2. This suggested that the oysters were growing.

Test Example 7 (Deodorization test of malodorous gas using the nutrient supply material of the present invention)
Deodorization tests were conducted on hydrogen sulfide, ammonia, amines, mercaptans, propionaldehyde, and methyl ethyl ketone, representing malodorous gases generated from methane fermentation digestive juices and nutrient supply materials, using the following method.
Near the liquid level of the methane-fermented digestive juice, hydrogen sulfide detection tube (No. 4LK: manufactured by Gastech Co., Ltd.), ammonia detection tube (No. 3L: manufactured by Gastec Co., Ltd.), and amines detection tube (No. 180: manufactured by Gastec Co., Ltd.) are placed. (manufactured by Gastech Co., Ltd.), mercaptans detection tube (No. 70L: made by Gastech Co., Ltd.), propionaldehyde (No. 151L: made by Gastec Co., Ltd.), and methyl ethyl ketone (No. 151L: made by Gastec Co., Ltd.) were brought close together. , the respective concentrations were measured.
The concentration of hydrogen sulfide generated from methane fermentation digestive fluid is 4 ppm, the concentration of ammonia is 15 ppm, the concentration of amines is 200 ppm, the concentration of mercaptans is less than 0.05 ppm, and the concentration of propionaldehyde is The concentration of methyl ethyl ketone was less than 2.1 ppm. Note that the concentration of these malodorous gases varies depending on the type of methane fermentation digestive juice, methane fermentation conditions, methane fermentation substrate, etc.
Similarly, when each detection tube was brought close to the surface of Sample 4 (nutrient supply material containing 10% seashells) prepared in Example 2 and the concentration of malodorous gas was measured, the concentration of hydrogen sulfide was 0. The concentration of ammonia is less than 0.2 ppm, the concentration of amines is less than 0.5 ppm, the concentration of mercaptans is less than 0.05 ppm, and the concentration of propionaldehyde is less than 2.4 ppm. and the concentration of methyl ethyl ketone was less than 2.1 ppm.
These results revealed that by using methane-fermented digestive fluid as a nutrient supply material, the generation of foul-smelling gases such as hydrogen sulfide can be suppressed.

Claims (10)

Nutrient supply material containing methane-fermented digestive fluid or its concentrate and shells. The nutrient supply material according to claim 1, wherein the nutrient contains at least one selected from the group consisting of nitrogen (N), phosphorus (P), and silicon (Si). The nutrient supply material according to claim 1, wherein the nutrient is nitrogen, and the elution of the nitrogen is controlled to 0.02 to 50 mg-N/g as ammonia nitrogen. The nutrient supply material according to claim 1, wherein the nutrient is phosphorus, and the elution of the phosphorus is controlled to 0.0085 to 7.7 mg-P/g as phosphate phosphorus. The nutrient supply material according to claim 1, wherein the nutrient is silicon, and the elution of the silicon is controlled to 0.01 to 225 mg-Si/g as silicate silicon. The nutrient supply material according to claim 1, having a compressive strength of 15 to 90 mN/mm ² . The nutrient supply material according to claim 1, wherein the amount of the shell added to the methane-fermented digestive fluid is 7.5 to 33.5%. The nutrient supply material according to claim 1, wherein the shell is an oyster shell. An algae growth promoting material comprising a methane fermentation digestive juice or its concentrate and a nutrient supplying material containing shells. A material for controlling the growth rate of algae, comprising a nutrient supply material containing methane-fermented digestive fluid or its concentrate, and shells.