Seaweed cultivation apparatus and seaweed cultivation method

Abstract

The present invention provides a seaweed cultivation apparatus that can be relatively easily moved and installed at the required location on land, and that can cultivate seaweed stably and efficiently without being affected by adverse weather conditions or natural disasters. [Solution] The seaweed cultivation apparatus 1 comprises a floating container 2, a culture tank 3 installed inside the floating container 2, an artificial seawater supply unit 4 that receives fresh water W from a water source, adds artificial seawater base I to the fresh water W to create artificial seawater Wa, and supplies it to the culture tank 3, an air stirring device 5 that supplies air to the artificial seawater Wa stored in the culture tank 3, an air conditioner 6 that adjusts the temperature inside the floating container 2, a water temperature control device 7 that adjusts the temperature of the artificial seawater Wa stored in the culture tank 3, and a plant growth light 8 installed directly above the culture tank 3 that irradiates light onto seaweed A suspended in the artificial seawater Wa in the culture tank 3.

Description

Technical Field

[0001] The present invention relates to a seaweed cultivation device and a seaweed cultivation method for cultivating seaweeds such as Kappaphycus on land.

Background Art

[0002] Kappaphycus is a seaweed classified as a red alga. It is known that by mixing 0.2% of this Kappaphycus into cattle feed, the methane gas emissions from cattle can be reduced by up to 98%. However, with only natural Kappaphycus, it is impossible to meet the required amount for the assumed number of cattle to be raised. Therefore, it has been proposed to cultivate Kappaphycus to increase production. When cultivating Kappaphycus, marine cultivation can be considered. However, for example, it is vulnerable to disasters caused by natural phenomena such as typhoons. At present, stable production increase through marine cultivation is not achievable, and land cultivation is required.

[0003] Conventionally, as a method for land cultivation of seaweeds, for example, as disclosed in Patent Document 1, a water tank with an open top is installed on land, seawater pumped from the sea is injected into the water tank, and seaweeds are cultivated in the water tank.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the aforementioned land-based seaweed cultivation methods, it is desirable to install the tanks as close to the coast as possible in order to shorten the water supply channels for the seawater injected into the tanks. However, recently, there are few suitable locations for cultivation near the coast, and obtaining land for cultivation requires a large amount of land cost. In addition, cultivation in open-air tanks is susceptible to weather conditions. Furthermore, when cultivating *Lysimachia japonica* in tanks filled with seawater pumped from the ocean, bacteria and other substances in the seawater negatively affect the growth of *Lysimachia japonica*, so countermeasures are also necessary. For this reason, efficient land-based cultivation of *Lysimachia japonica* requires a large investment in equipment, and the results cannot be expected to justify the investment.

[0006] Furthermore, in recent years, the amount of abandoned farmland has been increasing in sparsely populated mountainous areas, becoming a major social problem, and there is a strong desire to make effective use of this abandoned land.

[0007] This invention has been made in view of the aforementioned problems of the conventional approach. The object of this invention is to provide a seaweed cultivation apparatus that can be relatively easily moved and installed at required locations on land, and that can stably and efficiently cultivate seaweed such as *Ulva perforata* without being affected by adverse weather conditions or natural disasters. Another object of this invention is to provide a seaweed cultivation method that can effectively utilize abandoned farmland and cultivate seaweed such as *Ulva perforata* with relatively little capital investment, without being affected by weather conditions or natural disasters. Means for solving the problems and effects of the invention.

[0008] A seaweed cultivation apparatus according to the first aspect of the present invention can be configured to include: a floating container; a cultivation tank installed inside the floating container; an artificial seawater supply unit that receives fresh water from a water source, adds artificial seawater mix to the fresh water to create artificial seawater, and supplies it to the cultivation tank; an air stirring device that supplies air to the artificial seawater stored in the cultivation tank; an air conditioner that adjusts the temperature inside the floating container; a water temperature control device that adjusts the temperature of the artificial seawater stored in the cultivation tank; and a plant cultivation light installed directly above the cultivation tank that irradiates light onto seaweed suspended in the artificial seawater of the cultivation tank.

[0009] With the above configuration, it is possible to provide a seaweed cultivation device that can be relatively easily transported and installed at the required installation location on land, and that can cultivate *Lysimachia japonica* stably and efficiently without being affected by adverse weather conditions or natural disasters.

[0010] The seaweed cultivation apparatus according to the second aspect of the present invention can be configured such that the water source is groundwater near the installation site of the offshore container.

[0011] A seaweed cultivation apparatus according to a third aspect of the present invention can be configured to include at least the air stirring device, the air conditioner, the water temperature control device, and a storage battery that supplies power to the plant cultivation lighting, and a solar cell installed on the marine container that supplies power to the storage battery.

[0012] This configuration, which converts sunlight into electricity for use, is also advantageous from the perspective of achieving the Sustainable Development Goals (SDGs).

[0013] A seaweed cultivation apparatus according to the fourth aspect of the present invention can be configured such that the seaweed belongs to the divisions Rhodophyta or Chlorophyta.

[0014] A seaweed cultivation apparatus according to the fifth aspect of the present invention can be configured such that the seaweed is *Ulva perforatum*.

[0015] A seaweed cultivation method according to a sixth aspect of the present invention can be configured to include: a cultivation device preparation step of preparing a seaweed cultivation device; a water supply unit installation step of installing a water supply unit that can supply and stop groundwater from abandoned farmland or near said abandoned farmland, before or after the cultivation device preparation step; a cultivation device installation step of moving and installing the seaweed cultivation device prepared in the cultivation device preparation step on said abandoned farmland; and a water source connection step of connecting the artificial seawater supply unit and the water supply unit of the seaweed cultivation device installed in the cultivation device installation step with a connecting pipe.

[0016] With the above configuration, the main components of the seaweed cultivation equipment can be transported together with the shipping container, allowing for timely and relatively easy installation on abandoned farmland. Furthermore, when acquiring abandoned farmland for cultivation, the land purchase cost can be kept relatively low. In addition, since the seaweed cultivation equipment can be moved from its installation site to another location as needed, property tax is not required. As a result, abandoned farmland can be effectively utilized, and *Lysimachia japonica* can be cultivated stably and efficiently with relatively little capital investment, unaffected by weather or natural disasters. [Brief explanation of the drawing]

[0017] [Figure 1] This is an explanatory diagram of a seaweed cultivation apparatus according to one embodiment of the present invention. [Figure 2] This is a flowchart of a seaweed cultivation method according to one embodiment of the present invention. [Modes for carrying out the invention]

[0018] Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments shown below are illustrative examples of seaweed cultivation apparatus and seaweed cultivation methods for realizing the technical concept of the present invention, and the present invention does not limit them to these. Furthermore, this specification does not limit the components shown in the claims to the components of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments are not intended to limit the scope of the present invention to these, unless otherwise specifically stated, but are merely illustrative examples. Note that the size and positional relationships of the components shown in each drawing may be exaggerated for clarity of explanation.

[0019] As shown in Figure 1, the seaweed cultivation apparatus 1 according to one embodiment of the present invention comprises a floating container 2, a culture tank 3 installed inside the floating container 2, an artificial seawater supply unit 4 that adds artificial seawater base I to fresh water W to create artificial seawater Wa and supplies it to the culture tank 3, an air stirring device 5 that supplies air to the artificial seawater Wa stored in the culture tank 3, an air conditioner 6 that adjusts the temperature inside the floating container 2 to an appropriate value, a water temperature control device 7 that adjusts the temperature of the artificial seawater Wa stored in the culture tank 3, and a plant growth light 8 installed directly above the culture tank 3 that irradiates light onto seaweed A suspended in the artificial seawater Wa in the culture tank 3.

[0020] The shipping container 2 is a reusable transport unit designed for moving products and raw materials across regions and countries, and is also known as an intermodal cargo container. In this embodiment, the shipping container 2 is a standard product with a length of approximately 40 feet, a width of approximately 8 feet, and a height of approximately 8.5 feet. The shipping container 2 may be a used item, which would reduce the purchase cost.

[0021] The artificial seawater supply unit 4 includes a receiving pipe 41 that receives fresh water W from a water source, an artificial seawater production tank 42, an electric pump 43 that supplies the fresh water W received by the receiving pipe 41 to the artificial seawater production tank 42, an artificial seawater production device 44 that can produce artificial seawater Wa of the required concentration by periodically supplying an appropriate amount of artificial seawater base I (containing salt and other minerals, for example, Aquarium Systems' product name "Instant Ocean") to the fresh water W stored in the artificial seawater production tank 42, an electric pump 46 that supplies the artificial seawater Wa produced in the artificial seawater production tank 42 to the culture tank 3 through a supply pipe 45, and an electric pump 48 that is connected to a drain port 31 provided in the culture tank 3 through a drain pipe (not shown) and sends the wastewater of artificial seawater Wa from the culture tank 3 to the artificial seawater production tank 42 via a filtration and sterilization unit 47. The filtration and sterilization unit 47 can filter and sterilize the wastewater from the artificial seawater Wa for reuse in the production of artificial seawater Wa before sending it out. The artificial seawater production device 44, the filtration and sterilization unit 47, and the electric pumps 43, 46, and 48 are connected to the control panel 49 by electrical wires and are configured to operate as needed.

[0022] The air agitation device 5 sends air into the artificial seawater Wa in the culture tank 3 by an air pump and a tube or the like, and also has a function of circulating the artificial seawater Wa.

[0023] The water temperature adjustment device 7 uses a heat pump that compresses and expands a refrigerant with a compressor, and has a water heat exchanger 71 disposed in the culture tank 3 and an air heat exchanger (not shown) disposed outside the marine container 2. It heats and cools the artificial seawater Wa in the culture tank 3 through the water heat exchanger 71, can detect the temperature of the artificial seawater Wa in the culture tank 3, and can be automatically controlled so that the detected temperature becomes a preset temperature. The water heat exchanger 71 can heat or cool the sucked artificial seawater Wa while sucking and discharging the artificial seawater Wa, and reflux the artificial seawater Wa into the culture tank 3.

[0024] The lighting 8 for plant cultivation contains a lot of specific wavelengths for promoting the growth of plants and has the brightness (photosynthetic photon flux density) necessary for plants to grow healthily. In this embodiment, LEDs are used as the light source.

[0025] Furthermore, the seaweed cultivation device 1 includes a storage battery 9 that supplies power to the artificial seawater supply unit 4, the air agitation device 5, the air conditioner 6, the water temperature adjustment device 7, the lighting 8 for plant cultivation, and the LED lamp 12, and a solar cell 10 installed outside the marine container 2 that supplies power to the storage battery 9. In the case of this embodiment, the solar cell 10 is a perovskite solar cell that uses a compound having a perovskite crystal structure as a power generation body.

[0026] Inside the marine container 2, there are provided an LED lamp 12 for lighting and a solar cell 12. The solar cell 12 is the same as the solar cell 10, can receive light from the lighting 8 for plant cultivation and the LED lamp 12 to generate electricity, and can supply the generated power to the storage battery 9.

[0027] A power distribution panel 13 is installed in the shipping container 2, and the battery 9 and the power distribution panel 13 are connected by an electrical circuit. In addition, the power distribution panel 13 is connected by an electrical circuit to the control panel 49 of the artificial seawater supply unit 4, the air conditioner 6, the water temperature control device 7, the plant growth lighting 8, the air agitator 5, and the LED lamp 12.

[0028] During aquaculture, the artificial seawater supply unit 4 is always operational, the air agitator 5, air conditioner 6, and water temperature control device 7 are always operating, and the plant growth lighting 8 is always on. However, the LED lamp 12 is only turned on when an operator enters the interior of the marine container 2 for inspection or maintenance, regardless of whether aquaculture is in progress or not.

[0029] The water source from which the receiving pipe 41 receives fresh water W is groundwater W, and the receiving pipe 41 receives the supply of groundwater W from the water supply section 14 through the connecting pipeline 15. The water supply section 14 has a driven pipe 141 that reaches the groundwater vein W, which was installed by boring into abandoned farmland, and a valve 142 installed above ground. The groundwater W pumped up through the driven pipe 141 can be supplied to and stopped from the connecting pipeline 15 by the valve 142. (Seaweed cultivation method)

[0030] Figure 2 is a flowchart of a seaweed cultivation method according to one embodiment of the present invention, which comprises a cultivation device preparation step ST1 in which a seaweed cultivation device 1 is prepared; a water supply unit installation step ST2 in which, after the completion of the cultivation device preparation step ST1, a water supply unit 14 is installed that uses abandoned farmland or groundwater W near the abandoned farmland as a water source and is capable of supplying and stopping the groundwater W; a cultivation device installation step ST3 in which the seaweed cultivation device 1 prepared in the cultivation device preparation step ST1 is moved to the abandoned farmland and installed; a water source connection step ST4 in which the artificial seawater supply unit 4 and the water supply unit 14 of the seaweed cultivation device 1 installed in the cultivation device installation step ST3 are connected by a connecting pipe 15; and a cultivation step ST5 in which seaweed A is placed in a culture tank 3 filled with artificial seawater Wa and cultivated.

[0031] In the aquaculture equipment preparation process ST1, a sea container 2, culture tanks 3, artificial seawater supply unit 4, air agitator 5, air conditioner 6, water temperature control unit 7, plant growth lighting 8, storage battery 9, solar cells 10, solar cells 11, LED lamps 12, and a distribution board 13 are procured. Then, installation locations for the culture tanks 3, artificial seawater supply unit 4, air agitator 5, air conditioner 6, water temperature control unit 7, plant growth lighting 8, solar cells 10, solar cells 11, LED lamps 12, and distribution board 13 are secured in the sea container 2, and these items are made ready for installation in the secured locations. After that, all or some of these items are installed in the designated locations secured in the sea container 2 as needed.

[0032] In the aquaculture equipment installation process ST3, the culture tanks 3, artificial seawater supply unit 4, air agitator 5, air conditioner 6, water temperature control device 7, plant growth lighting 8, storage battery 9, solar cell 10, solar cell 11, LED lamp 12, and power distribution board 13 that were installed in the designated locations on the shipping container 2 in the aquaculture equipment preparation process ST1 are transported together with the shipping container 2.

[0033] Of the culture tank 3, artificial seawater supply unit 4, air agitator 5, air conditioner 6, water temperature control device 7, plant growth lighting 8, storage battery 9, solar cell 10, solar cell 11, LED lamp 12, and distribution board 13, those that are not attached to the shipping container 2 in the aquaculture equipment preparation process ST1 will be attached to their designated positions on the shipping container 2 after the shipping container 2 has been installed on the abandoned farmland. Those that can be housed inside the shipping container 2 among those to be housed in their designated positions on the shipping container 2 should be housed inside the shipping container 2 and transported to the abandoned farmland, provided there are no obstacles, in order to save on transportation costs.

[0034] In the water source connection process ST4, the worker connects the valve 142 of the water supply unit 14 and the receiving pipe 41 of the artificial seawater supply unit 4 with the connecting pipeline 15, and then opens the valve 142 of the water supply unit 14.

[0035] In the culture process ST5, the artificial seawater supply unit 4 operates the electric pump 43 to put fresh water W into the artificial seawater production tank 42, and at the same time adds an appropriate amount of artificial seawater base I from the artificial seawater production device 44 to the fresh water W in the artificial seawater production tank 42 to make artificial seawater Wa. The electric pump 46 then operates to send the artificial seawater Wa from the supply pipe 45 to the culture tank 3, where it is stored until it reaches a predetermined depth.

[0036] Once the artificial seawater Wa has accumulated in the culture tank 3, the worker manually places the previously obtained seaweed seeds into the artificial seawater Wa in the culture tank 3. In this embodiment, the seaweed seeds are those of *Lysimachia japonica* A, and are the tips of the lateral branches that branch off from the main stem of *Lysimachia japonica* A.

[0037] During cultivation, the plant growth light 8 is turned on to irradiate the seaweed A, the water temperature control device 7 maintains the temperature of the artificial seawater Wa at approximately 22-24 degrees Celsius, and the air agitator 5 blows air into the artificial seawater Wa to supply oxygen to it. Furthermore, the air conditioner 6 maintains the temperature inside the marine container 2 at the required temperature. The irradiation of seaweed A with light from the plant growth light 8 is usually done intermittently at the required interval, for example, by turning the plant growth light 8 on only during the day and turning it off at night.

[0038] During cultivation, the artificial seawater supply unit 4 produces new artificial seawater Wa approximately once every one to two weeks and supplies it to the culture tank 3. At the same time, it collects the wastewater from the culture tank 3, filters and sterilizes it, and reuses it for the production of artificial seawater Wa.

[0039] When the seaweed seeds grow in the culture tank 3 to the required size of seaweed A, the worker manually removes the seaweed A from the culture tank 3 for harvesting.

[0040] According to the present invention, its embodiments can be varied in various ways as needed. For example, the seaweed cultivated using the seaweed cultivation apparatus of the present invention is not limited to those belonging to the Rhodophyta division, such as *Ulva perforatum*, but may also belong to the Chlorophyta division. Examples of plants belonging to the Chlorophyta division include Ulva lactuca, Lyophyllum decastes, Ajuga reptans, and Monostroma. The seaweed species placed in the culture tank may also vary depending on the type of seaweed being cultivated. Seaweed spores or single cells derived from spores may also be used as seaweed species. Furthermore, cultivation can be carried out by growing individual seaweed species to a large size, or by propagating seaweed spores or single cells derived from spores, and either method may be used. In addition, if commercial power lines are laid near the abandoned farmland F where the seaweed cultivation apparatus is installed, power can be supplied from those lines to the distribution board 13 installed in the shipping container 2. Alternatively, solar panels may be installed on the abandoned farmland F, and the storage battery 9 and solar panels may be electrically connected so that power can be supplied from the solar panels to the storage battery 9. Furthermore, if a water pipe runs near the abandoned farmland F, the water pipe can be connected to the receiving pipe 41 of the artificial seawater supply unit 4. The artificial seawater supply unit 4 may also continuously supply artificial seawater Wa during cultivation and collect wastewater, or it may be a flow-through type. In addition, the water supply unit installation process ST2, which involves installing a water supply unit 14 that uses groundwater W from the abandoned farmland or the vicinity of the abandoned farmland as a water source and can supply and stop the groundwater W, may be performed before the aquaculture equipment preparation process ST1, instead of installing the water supply unit 14 after the aquaculture equipment preparation process ST1. Furthermore, abandoned farmland includes fallow land and degraded farmland that are not currently used for fields. [Explanation of Symbols]

[0041] 1…Seaweed cultivation equipment 2…Sea containers 3…Culture tank;31…Drain port 4...Artificial seawater supply unit; 41...Water receiving pipe; 42...Tank for artificial seawater production; 43...Electric pump; 44...Artificial seawater production device; 45...Supply pipe; 46...Electric pump; 47...Filtration and sterilization unit; 48...Electric pump;Control panel...49 5. Air agitation device 6…Air conditioner 7…Water temperature control device; 71…Heat exchanger 8… Plant growing lights 9…Battery storage 10… Solar cells 11… Solar cells 12…LED lamps 13…Switchboard 14...Water supply section; 141...Punched pipe; 142...Valve 15...Connection pipe A... Seaweed (Hypholoma fasciculare) F... Abandoned farmland I... Artificial seawater mix W... Fresh water (groundwater) Wa…artificial seawater

Claims

1. Shipping containers and A culture tank installed inside the aforementioned shipping container, An artificial seawater supply unit that receives fresh water from a water source, adds artificial seawater mix to the fresh water to create artificial seawater, and supplies it to the culture tank, An air agitator that supplies air to the artificial seawater stored in the culture tank, An air conditioner for adjusting the temperature inside the aforementioned shipping container, A water temperature control device for adjusting the temperature of the artificial seawater stored in the culture tank, A plant cultivation light, installed directly above the culture tank, irradiates light onto seaweed suspended in the artificial seawater of the culture tank, A seaweed cultivation apparatus characterized by comprising the following features.

2. A seaweed cultivation apparatus according to claim 1, The seaweed cultivation apparatus is characterized in that the water source is groundwater near the installation site of the marine container.

3. A seaweed cultivation apparatus according to claim 1 or claim 2, At least the air agitator, the air conditioner, the water temperature control device, and the storage battery that supplies power to the plant growing lights, A solar cell installed on the shipping container supplies power to the aforementioned battery, A seaweed cultivation apparatus characterized by comprising the following features.

4. A seaweed cultivation apparatus according to claim 1, A seaweed cultivation apparatus characterized in that the seaweed belongs to the divisions Rhodophyta or Chlorophyta.

5. A seaweed cultivation apparatus according to claim 1, A seaweed cultivation apparatus characterized in that the seaweed is *Hypnum cupressiforme*.

6. A cultivation apparatus preparation step for preparing the seaweed cultivation apparatus described in claim 1, Before or after the preparation process for the aquaculture apparatus, a water supply installation process is performed in which groundwater from abandoned farmland or near said abandoned farmland is used as the water source, and a water supply unit capable of supplying and stopping the groundwater is installed. The aquaculture equipment installation step involves moving the seaweed cultivation equipment prepared in the aquaculture equipment preparation step to the abandoned farmland and installing it, A water source connection step is performed in which the artificial seawater supply section and the water supply section of the seaweed cultivation apparatus installed in the cultivation apparatus installation step are connected by a connecting pipe, A method for cultivating seaweed, characterized by including the following:

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