Algae cultivation device using CO2 solution

Abstract

To provide an algae culture device that can prevent algae from adhering to a culture water conditioning material and an air diffuser and can continuously culture algae.SOLUTION: An algae culture device 10 of the present invention comprises: a storage device 20 for storing a culture water 14; and a filtration device 30 that is provided in the storage device 20 and divides the storage device 20 into a culture water generation area 28 and a culture area 29, the filtration device 30 being formed so that the culture water 14 passes through and an alga 15 to be cultured are not allowed to pass therethrough, at least one of a culture water conditioning material 13 and an air diffuser 54 that releases CO2 into the culture water 14 being arranged in the culture water generation area 28, and the alga 15 being cultured in the culture area 29.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an algae culture device using a CO2 solution. [Background technology]

[0002] In the past, efforts to capture and effectively utilize CO2 have been attracting attention as a way to prevent global warming. One such effort has attracted attention, as disclosed in Patent Document 1, which is an algae culture that can fix CO2 in algae cells during the algae cultivation process. The cultured algae cells that have fixed CO2 can be used for various purposes, such as biofuels, chemical products, and aquaculture feed.

[0003] When cultivating algae, CO2 gas is dissolved in the culture water stored in the storage device to create CO2-dissolved culture water, and the algae are cultivated in this CO2-dissolved culture water. By continuously supplying CO2 gas, the CO2 content in the culture water is maintained above a certain level. The exhaust gas emitted from cement factories has a high CO2 concentration, which has been a concern from the perspective of preventing global warming, but cultivating algae using CO2 makes it possible to effectively utilize the CO2 emitted from cement factories.

[0004] However, with the above method of dissolving CO2 gas in the culture water, as the CO2 content in the culture water increases, the pH value of the culture water gradually decreases, making it acidic and unsuitable for algae survival, so the CO2 concentration cannot be increased beyond a certain level. In this regard, concrete waste, such as waste ALC, waste concrete, and waste sludge, contains calcium silicate. Therefore, adding concrete waste to the culture water as a culture water conditioner can prevent the culture water from becoming acidic and allow more CO2 to dissolve. Therefore, the algae cultivation method using CO2-dissolved culture water with concrete waste allows the algae to absorb sufficient CO2 during the growth process and immobilize it in the algae bodies. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. WO2013 / 015422 Summary of the Invention [Problem to be solved by the invention]

[0006] However, although the method of culturing algae by storing them together with other materials in a single storage device requires simpler equipment than two-tank culture, in which the produced culture water is transferred to a culture device and the algae are cultured there, it has the following issues: When cultivating algae in a single storage device, there is a possibility that algae will adhere to the culture water conditioner immersed in the culture water and to the aeration device for dissolving CO2. As a result, there are issues such as a decrease in the performance of the culture water conditioner, clogging of the aeration device, and a decrease in the amount of algae recovered because the entire amount of algae cannot be recovered. On the other hand, when dissolving CO2 in advance in two-tank culture, it is necessary to supply water containing a large amount of CO2 in order to cultivate more algae, which reduces the algae concentration in the recovered water and results in low efficiency.

[0007] The present invention has been made to solve the above problems, and aims to provide an algae culture device that can prevent algae from adhering to the culture water adjustment material and the aeration device, and that can continuously culture algae. [Means for solving the problem]

[0008] The algae culture apparatus of the present invention comprises a storage device that stores culture water, and a filtration device that is provided in the storage device and divides the interior of the storage device into a culture water production area and a culture area. The filtration device is formed so that the culture water passes through but not the algae being cultured. At least one of a culture water adjuster and an aeration device that releases CO2 into the culture water is disposed in the culture water production area, and the algae are cultured in the culture area.

[0009] Therefore, the algae culture device of the present invention can prevent algae from adhering to the culture water adjustment material and the aeration device, and can maintain a sufficient supply of CO2 and pH value to the algae, allowing for continuous algae culture with high efficiency.

[0010] Furthermore, the culture water conditioner of the present invention is preferably formed to be larger than the communication holes provided in the filtration device.

[0011] Therefore, the culture water conditioner of the present invention does not flow into the culture area where algae are cultured during the cultivation of algae, further reducing the possibility of algae adhering to the culture water conditioner. Also, impurities in the recovered water can be reduced.

[0012] In addition, it is preferable that at least a part of the filtration device of the present invention is modifiable.

[0013] Therefore, the filtration device of the present invention can be appropriately selected depending on the type of algae to be cultured.

[0014] In the algae culture apparatus of the present invention, the culture water supplied during the algae culture is preferably supplied to the culture water production region.

[0015] Therefore, in the algae culture device of the present invention, the culture water is supplied to the culture water production area and flows out from the culture water production area through the filtration device to the culture area, thereby reducing the possibility of algae adhering to the filtration device.

[0016] In the algae culture apparatus of the present invention, it is preferable that the culture water production region or the culture region is formed such that the entire outer surface thereof is surrounded by a filtration device.

[0017] Therefore, in the algae culture device of the present invention, the culture water can easily flow through the filtration device, reducing the possibility that the components contained in the culture water will become unevenly distributed within the storage device. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic diagram showing an algae culture apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing the filtering device of FIG. 1. [Figure 3] FIG. 3 is an enlarged view of part A in FIG. 2. [Figure 4] FIG. 1 is a cross-sectional view showing a test device for producing culture water. [Figure 5] FIG. 5 is a front view showing the filtering device of FIG. [Figure 6] 5 is a characteristic diagram showing the change over time in the pH value of the culture water produced by the culture water production test device of FIG. 4. [Figure 7] 5 is a characteristic diagram showing the change over time in the amount of dissolved CO2 in the culture water produced by the culture water production test device of FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0019] <Embodiment> 1 and 2, an algae culture apparatus 10 according to an embodiment of the present invention will be described. The present invention relates to an algae culture apparatus 10 including a storage device 20 for storing culture water 14, and a filtration device 30 for dividing the interior of the storage device 20 into a culture water production area 28 and a culture area 29. Within the storage device 20, which is separated by the filtration device 30, a culture water adjustment material 13 and an aeration device 54 for supplying CO2 to the culture water 14 are disposed in the culture water production area 28. The filtration device 30, which separates the culture water production area 28 from the culture area 29, is configured to allow the culture water 14 to pass through but not the algae 15 to be cultured, and the algae 15 to be cultured are cultivated in the culture area 29.

[0020] Figure 1 shows an algae culture apparatus 10 with some parts omitted. Figure 2 shows a filtration device 30, and Figure 3 shows an enlarged view of part A of the filtration device 30 in Figure 2. The algae culture apparatus 10 includes a storage device 20, a filtration device 30, a raw water supply device 40, and a CO2 supply device 50.

[0021] The algae 15 to be cultured in the present invention is not particularly limited and may be any algae 15 found in a wide range of habitats, including marine, brackish, and freshwater environments. Among these, diatoms, which are single-celled eukaryotic algae with siliceous shells, are primary producers in aquatic ecosystems and are the most important phytoplankton that serve as a nutrient source for aquatic organisms, making them important organisms for the growth of fish and other organisms. Diatoms also play an important role in photosynthesis, utilizing carbon dioxide dissolved in water to produce oxygen necessary for the growth of organisms (especially animals). Examples of algae 15 cultured in the algae culture device 10 include Chaetoceros gracilis, Chaetoceros calcitoranse, and coccolithophorid Gephyrocapsa oceanica.

[0022] The storage device 20 contains components for producing the culture water 14, a filtration device 30, and the produced culture water 14, and is used to cultivate algae 15. The storage device 20 is formed in a cylindrical shape with a bottom and an open top 22. It has a wall 21 that surrounds the entire side of the storage device 20, and a bottom 23. One or more drainage devices 25 are provided on the wall 21 between approximately the center and the top end in the height direction. The drainage devices 25 are hollow pipes formed in an L shape. One end 26 of the drainage device 25 is perpendicular to the wall 21, and the other end 27 of the drainage device 25 faces downward. The drainage devices 25 are attached in communication with holes provided in the wall 21. When the culture water 14 in the storage device 20 rises to a predetermined height, the culture water 14 overflows and flows out of the storage device 20 through the drainage device 25. At that time, the algae 15 also flow out and are collected together with the overflowing culture water 14. Note that the storage device 20 in Figure 1 is illustrated with the front half of the wall 21 omitted to make it easier to understand the interior of the storage device 20.

[0023] The filtration device 30 will be described with reference to Figures 2 and 3. The filtration device 30 is a device that allows the culture water 14 to pass through but does not allow the algae 15 to be cultured to pass through. The filtration device 30 divides the interior of the storage device 20 into a culture water production area 28 and a culture area 29. The filtration device 30 is formed in a cylindrical shape with a bottom and an open upper portion 34, and the culture water production area 28 is formed inside the filtration device 30. The filtration device 30 has an upper structural member 31, a lower structural member 32, an intermediate structural member 33, and a filtration member 36. The upper structural member 31 is annular, the intermediate structural member 33 is linear, and the lower structural member 32 is disk-shaped. The multiple intermediate structural members 33 are arranged between the upper structural member 31 and the lower structural member 32 on the outer circumferential surface of the cylindrical shape, parallel to the central axis of the cylindrical shape and at equal intervals. Both ends of each intermediate structural member 33 are fixed to the upper structural member 31 and the lower structural member 32, respectively. The filtration member 36 is wound into a cylindrical shape to fit the shapes of the upper structural member 31, the lower structural member 32, and the intermediate structural member 33, and is removably held in this state by a fixing device (not shown). That is, the culture water producing region 28 is formed surrounded by the filtration device 30, and the filtration device 30 may be formed in a shape other than a cylindrical shape, for example, a rectangular parallelepiped shape.

[0024] One filtration device 30 is disposed approximately at the center of the storage device 20, which is formed in a substantially cylindrical shape. The entire outer surface of the filtration device 30, which contacts the culture region 29, is spaced apart from the inner surface of the wall 21 of the storage device 20. This allows the culture water 14 generated in the culture water production region 28 to quickly and efficiently flow from the entire outer surface of the filtration device 30 from the culture water production region 28 within the filtration device 30 to the culture region 29 outside the filtration device 30 in all directions. This reduces the possibility of uneven distribution of components in the culture water 14, contributing to the rapid growth of the algae 15. Regarding the arrangement of the algae culture device 10, multiple filtration devices 30 may be disposed within the storage device 20. In a storage device 20 formed in a substantially cylindrical or rectangular parallelepiped shape, it is preferable that multiple filtration devices 30 be disposed as evenly spaced as possible within the storage device 20. In either case, it is preferable that the entire outer surface of each filtration device 30 be spaced apart from the inner surface of the wall 21 of the storage device 20. This arrangement allows the culture water 14 produced in the filtration device 30 to easily diffuse throughout the storage device 20, thereby reducing uneven distribution of the components contained in the culture water 14 within the storage device 20.

[0025] The filtration member 36 is a sheet-like member having numerous through-holes 37 formed through both sides of the filtration member 36. The filtration member 36 is selected depending on the type, size, and other characteristics of the algae 15 to be cultured. For example, the size of the through-holes 37 is determined so that the algae 15 to be cultured will not pass through the filtration member 36 regardless of the angle at which the algae 15 is formed relative to the filtration member 36. Specifically, the through-holes 37 are selected to have a minimum dimension B smaller than the shortest dimension of the algae 15 to be cultured so that the algae 15 to be cultured will not pass through the filtration member 36. The larger the algae 15, the larger the through-holes 37 can be, allowing the high-concentration CO2 solution to penetrate more smoothly. The minimum dimension of the through-holes 37 is, for example, 0.1 μm to 10 μm. The filtration member 36 is removably attached to the cylinder and can be changed depending on the algae 15 to be cultured. The filtration member 36 can be made of metal or resin depending on the required strength and durability. This allows the filter member 36 to be changed to one with an optimum size or material for the communication holes 37.

[0026] The raw water supply device 40 supplies raw water 11, which is the raw material for the culture water 14 used to culture algae 15. The raw water supply device 40 has a raw water pipe 41. The raw water pipe 41 has one end 42 immersed in the culture water 14 in the culture water production area 28 of the storage device 20, and the other end 43. A raw water supply source 44 is connected to the other end 43. The raw water 11 supplied from the raw water supply device 40 is not particularly limited as long as it is water in which algae 15 can grow, and may be freshwater, brackish water, or seawater. Naturally occurring seawater, river water, lake water, or the like may also be used as the raw water 11. The raw water 11 is selected depending on the algae 15 to be cultured. The raw water 11 is injected into the culture water production area 28, which is surrounded by a filtration member 36, and its components are adjusted by the action of a culture water conditioner 13 and an aeration device 54 that releases CO2, thereby producing the culture water 14. The generated culture water 14 flows out into the culture region 29 through the filtration member 36 due to the water pressure of the injected raw water 11. Therefore, the generated culture water 14 always flows out from the filtration member 36, which reduces the possibility that the algae 15 in the culture region 29 will adhere to the filtration member 36. The amount of raw water 11 to be added may be the minimum amount appropriate for the growth rate or algae concentration of the algae 15.

[0027] The CO2 supply device 50 supplies high-concentration CO2 gas to be dissolved in the raw water 11. The CO2 supply device 50 includes a CO2 pipe 51 and an aeration device 54. The CO2 pipe 51 has one end 52 immersed in the culture water 14 in the culture water production area 28 in the storage device 20, and the other end 53. The aeration device 54 is connected to the one end 52. The aeration device 54 is, for example, an aeration stone. The other end 53 is connected to a CO2 supply source 55. The CO2 supply source 55 is, for example, a CO2 gas cylinder or an exhaust pipe from a high-concentration CO2 gas generation unit in a cement factory. The CO2 supply source 55 continuously supplies high-concentration CO2 gas for a certain period of time or longer.

[0028] The CO2 gas to be supplied may consist solely of CO2 gas, but from the standpoint of ease of availability, it is generally acceptable to supply a gas containing CO2 gas at a ratio of preferably 2% by volume or more, more preferably 4% by volume or more, even more preferably 5% by volume or more, even more preferably 20% by volume or more, even more preferably 40% by volume or more, even more preferably 60% by volume or more, and particularly preferably 80% by volume or more. If the ratio is 5% by volume or more, carbon dioxide-containing water can be obtained in a shorter time. Examples of gases containing CO2 gas include exhaust gas generated in the cement manufacturing process (CO2 gas concentration: approximately 20% by volume) and gas separated and recovered from the exhaust gas (CO2 gas concentration: approximately 100% by volume).

[0029] The amount of carbon dioxide in the carbon dioxide-containing water is preferably 500 mg / L or more. The amount of carbon dioxide in the carbon dioxide-containing water is preferably 550 mg / L or more, more preferably 600 mg / L or more, even more preferably 700 mg / L or more, even more preferably 800 mg / L or more, even more preferably 1,000 mg / L or more, and particularly preferably 1,200 mg / L or more. If the amount is less than 500 mg / L, the effect of promoting the growth of algae 15 will be reduced. From the viewpoint of ease of production, etc., the upper limit of the amount is preferably 3,000 mg / L, more preferably 2,800 mg / L, and particularly preferably 2,500 mg / L.

[0030] Next, the culture water conditioner 13 will be described. As described above, the filtration device 30 divides the interior of the storage device 20 into a culture water production region 28 and a culture region 29, and the culture water production region 28 is formed inside the filtration device 30. The culture water conditioner 13, which is a calcium silicate-containing material, is placed in a state immersed in the culture water 14 in the culture water production region 28. The calcium silicate-containing material is a material containing a compound containing silicic acid and calcium, such as calcium silicate hydrate. By supplying carbon dioxide gas to the raw water 11 in the presence of the calcium silicate-containing material, the amount of CO2 gas dissolved can be increased, thereby stabilizing the pH value of the culture water 14 within the neutral range. By using the calcium silicate-containing material, the pH value of the culture water 14 can be maintained within the range of pH 6.0 to 8.0, for example.

[0031] Furthermore, the calcium silicate-containing material dissolves silicic acid and calcium contained in the material in the culture water 14. Since silicic acid and calcium are important components for the proliferation and growth of algae 15, particularly diatoms, dissolving silicic acid and calcium into the water can further stabilize the growth of algae 15, particularly diatoms, and further promote proliferation. Examples of calcium silicate-containing compounds include tobermorite, xonotlite, CSH gel, foshagite, gyrolite, hillebrandite, and wollastonite.

[0032] Tobermorite is a crystalline calcium silicate hydrate with a plate-like morphology of Ca5·(SiO 18 H2)·4H2O, plate-like form of Ca5·(SiO 18 H2), fibrous form of Ca5·(SiO 18 It has a chemical composition such as HCl.H2·8H2O.

[0033] Xonotlite is a crystalline calcium silicate hydrate, which is a fibrous form of Ca6·(SiO 17 )·(OH)2, etc.

[0034] CSH gel has the chemical composition αCaO·βSiO2·γH2O (where α / β = 0.7 to 2.3, γ / β = 1.2 to 2.7). Specifically, it can be calcium silicate hydrate with the chemical composition 3CaO·2SiO2·3H2O.

[0035] Foshagite has a chemical composition such as Ca4(SiO3)3(OH)2.

[0036] Gyrolite is (NaCa2)Ca 14 (Si 23 Al)O 60 It has a chemical composition such as (OH)8·14H2O.

[0037] Hillebrandite has the chemical composition Ca2SiO3(OH)2.

[0038] Wollastonite is a fibrous or columnar shaped material with a chemical composition of CaO·SiO2.

[0039] The calcium silicate-containing material may contain one of the above compounds alone or two or more of them.

[0040] In addition, calcium silicate-containing materials may also be used, such as building materials containing calcium silicate, such as aerated lightweight concrete (ALC) primarily composed of tobermorite or thermal insulation materials containing xonotlite, for example, scrap wood or waste wood. Among these, from the standpoints of ease of acquisition and economy, it is preferable to use aerated lightweight concrete (ALC) primarily composed of tobermorite. Furthermore, from the standpoint of promoting the use of waste, it is more preferable to use scraps of aerated lightweight concrete generated during the manufacturing process of aerated lightweight concrete or at construction sites.

[0041] Here, lightweight aerated concrete is made of tobermorite and unreacted silica, and has a porosity of about 80% by volume. Here, porosity refers to the ratio of the total volume of voids to the total volume of concrete. The ratio of tobermorite in lightweight aerated concrete is 65 to 80% by volume, with the entire solid phase excluding the voids inside the lightweight aerated concrete being 100% by volume. Lightweight aerated concrete can be obtained, for example, by autoclave curing raw materials (for example, a hardened product made from a mixture of these) containing silica powder, cement, quicklime powder, a foaming agent (for example, aluminum powder), water, etc.

[0042] The calcium silicate-containing material is preferably porous, so that when the calcium silicate-containing material is immersed in water, air present in the porous portions of the material is pushed out into the culture water 14, thereby preventing a decrease in the amount of dissolved oxygen in the culture water 14.

[0043] The culture water conditioner 13 is supplied as granules. The particle size of the culture water conditioner 13 is preferably 6 mm or less, more preferably 5 mm or less, and particularly preferably 4 mm or less, from the viewpoint of dissolving a larger amount of silicic acid into water. The lower limit of the particle size is preferably 0.01 mm, more preferably 0.05 mm, and particularly preferably 0.1 mm, from the viewpoint of reducing the energy required for pulverization and preventing the calcium silicate-containing material from flowing out or floating to the water surface.

[0044] From the viewpoint of dissolving a larger amount of silicic acid into water, the particle size distribution of the culture water conditioner 13 is such that it contains particles having a particle size of 1 mm to 4 mm in a proportion of 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0045] The amount of granules made of calcium silicate-containing material relative to the raw water is preferably 1 g / L or more, more preferably 5 g / L or more, even more preferably 8 g / L or more, even more preferably 20 g / L or more, and particularly preferably 40 g / L or more. From the viewpoint of material costs, the upper limit of the amount is preferably 100 g / L, more preferably 80 g / L, and particularly preferably 70 g / L.

[0046] The algae culture device 10 of the present invention allows the culture water 14 to contain a larger amount of CO2 gas. Furthermore, even if the amount of CO2 gas in the culture water 14 increases, the pH value of the culture water 14 can be maintained in a constant range near neutral. The preferred pH value of the culture water 14 varies depending on the type of algae 15, but from the perspective of further promoting the growth of the algae 15, it is preferably 6.0 to 8.0, more preferably 6.2 to 7.8, even more preferably 6.3 to 7.7, and particularly preferably 6.4 to 7.6.

[0047] [Production test of culture water 14] The results of a test to produce culture water 14 conducted based on the present invention are described below with reference to Figures 4 and 5. The test to produce culture water 14 was conducted using a test device (hereinafter referred to as the regular test device) that simply reproduced the algae culture device 10 shown in Figure 1 using a beaker 60. Figure 4 is a cross-sectional view of the beaker 60. Figure 5 is a front view of the filtration device 70 shown in Figure 4. The container device 20 in the test device used in the test to produce culture water 14 was a plastic beaker 60 with a capacity of 1 L. The filtration device 70 was made by preparing a frame member 71 that fit snugly into the inner shape of the diameter of the beaker 60, and attaching a plankton net with communicating holes measuring 1 µm to the frame member 71 as the filtration member 72.

[0048] Artificial seawater was prepared from tap water as raw water. The artificial seawater was prepared by adding 3% Sigma sea salts to tap water. The culture water conditioner 13 was a calcium silicate compound (particle size 1-4 mm) separated by a filtration device 70. 10,000 mg / L of the culture water conditioner was added to one area of ​​a beaker 60 corresponding to the culture water production area 28. Furthermore, one end 52 of the CO2 pipe 51 of the CO2 supply device 50 was connected to an aeration stone (aeration device 54) and placed in the culture water production area 28, and the other end 53 was connected to a CO2 gas cylinder as a CO2 supply source 55. As comparative examples, a test apparatus without the filtration device 70 (hereinafter, comparative apparatus 1) and a test apparatus without the filtration device 70 and the culture water conditioner 13 (hereinafter, comparative apparatus 2) were also prepared.

[0049] Using the test device constructed as described above, the change in pH value and the amount of dissolved CO2 of the culture water 14 over time were measured. CO2 gas was supplied to all three devices: the regular test device, comparative device 1, and comparative device 2; air-mixed CO2 gas (6% CO2 concentration) was supplied at 0.5 L / min. The culture water 14 was sampled from four locations on the regular test device: 1. culture water production area 28, 2. culture area 29, 3. comparative device 1, and 4. comparative device 2, and the pH value and amount of dissolved CO2 were measured. CO2 measurements were performed using a portable carbon dioxide concentration meter manufactured by Toa DKK.

[0050] Tables 1 and 2 show the results of the production test of the culture water 14. In addition, FIGS. 6 and 7 are graphs of the results of Tables 1 and 2.

[0051] [Table 1]

[0052] [Table 2]

[0053] Referring to Figure 6, the changes in pH value during the culture water 14 production test will be considered. In 4. Comparative Example 2, where the culture water conditioner 13 was not added, the pH value of the culture water 14 changed from 7.9 at the start of the test to 6.0, which is more acidic, after 24 hours, and this state was maintained. On the other hand, the pH values ​​of the culture water 14 in 1. culture water production area 28, 2. culture area 29, and 3. comparative device 1, where the culture water conditioner 13 was added, changed from 7.9 at the start of the test to 7.1 to 7.3 after 24 hours, maintaining a state close to ideal. Furthermore, the pH values ​​of the culture water 14 in 1. culture water production area 28 and 2. culture area 29 after 24 hours were 7.3 and 7.1, respectively. Although there was a slight difference, algae 15 could be cultivated in either case.

[0054] Referring to Figure 7, the change in CO2 dissolution amount during the culture water 14 production test will be considered. In 4. Comparative Example 2, in which the culture water conditioner 13 was not added, the CO2 dissolution amount in the culture water 14 changed from 22 mg / L at the start of the test to 220 mg / L after 24 hours. On the other hand, in 1. Culture water production area 28, 2. Cultivation area 29, and 3. Comparative device 1, in which the culture water conditioner 13 was added, the CO2 dissolution amount in the culture water 14 increased significantly from 22 mg / L at the start of the test to 1,408 to 1,815 mg / L after 24 hours. This indicates that all of the test devices 1 to 3 provided CO2 dissolution amounts suitable for cultivating algae 15. Note that the CO2 dissolution amounts in 1. Culture water production area 28 and 2. Cultivation area 29 at 24 hours after the start of the test were 1,815 mg / L and 1,408 mg / L, respectively. Regarding the differences in pH value and amount of dissolved CO2, it is thought that the installation of the filtration device 70 affected the fluidity of the culture water 14, resulting in an imbalance in the components contained in the culture water 14.

[0055] Furthermore, based on the pH value in the above test, it is estimated that silicic acid, calcium, etc. contained in the calcium silicate-containing material, which is the culture water adjuster 13, are also dissolved into the culture water 14, and the algae culture device 10 of the present invention can contribute to the efficient cultivation of algae 15.

[0056] The algae culture apparatus 10 of the present invention can prevent algae bodies from adhering to the culture water conditioner 13, the aeration device 54, etc., thereby reducing maintenance work such as preventing clogging. The algae culture apparatus 10 can also continuously dissolve CO2, allowing for efficient cultivation. The algae culture apparatus 10 can also easily separate and recover algae bodies, allowing for efficient recovery of the cultured algae 15. The algae culture apparatus 10 can also perform all cultivation processes in a single-tank storage device 20, thereby reducing the scale of the facility. The algae culture apparatus 10 can also use the filtration device 30 to allow the culture water 14 to flow in all directions, preventing uneven distribution of the components contained in the culture water 14, even if pH or CO2 fluctuations occur as the culture progresses.

[0057] Modifications of the embodiment of the present invention will be described below.

[0058] At least a portion of the upper structural member 31, lower structural member 32, intermediate structural member 33, and filtering member 36 that constitute the filtering device 30 may be formed from a conductive material. Alternatively, in addition to the above-mentioned members, other members may be made from a conductive material in a net-like, rod-like, sheet-like, ring-like, or other desired shape, and may be placed over or fixed to the filtering device 30. By passing an electric current through the members made from the above-mentioned conductive material, the algae 15 can be affected, and the adhesion and growth of the algae 15 on the filtering device 30 can be reduced.

[0059] The air diffuser 54 may be a microbubble generator. The size of the microbubbles generated by the microbubble generator is 1 to 100 μm, which is smaller than that of a typical air diffuser 54, resulting in high solubility and reducing the amount of CO2 gas discharged without dissolving. This improves the CO2 dissolution efficiency. The presence of microbubbles in the culture water production region 28 also affects the algae 15, reducing adhesion and growth of the algae 15 on the filtration device 30. Furthermore, by providing a vibration intensity generator to the filtration device 30 and periodically vibrating the filtration device 30, it is possible to reduce adhesion of the algae 15.

[0060] The region surrounded by the filtration device 30 may be the culture region 29, not the culture water production region 28. The algae culture device 10 may also be provided with a plurality of filtration devices 30, so that one or more culture water production regions 28 and one or more culture regions 29 are each surrounded by a filtration device 30.

[0061] According to the algae culture device 10 of the present invention, an environment suitable for culturing algae 15 can be created, the possibility of algae 15 adhering to the culture water adjustment material 13 and the aeration device 54 can be reduced, and the algae 15 can be cultured continuously. [Explanation of symbols]

[0062] 10 Algae culture device, 13 Culture water conditioner, 20 Storage device, 28 Culture water production area, 29 Culture area, 30 Filtration device.

Claims

1. a storage device for storing culture water; and An algae culture apparatus comprising a filtration device provided in the storage device and dividing the storage device into a culture water production area and a culture area, The filtration device is formed so as not to allow the culture water to pass through the algae to be cultured, The culture water producing region contains a culture water conditioner containing a calcium silicate-containing material, and a CO ２ and an aeration device that emits an aeration gas, and the algae are cultivated in the cultivation area.

2. The algae culture apparatus according to claim 1 , wherein the culture water adjusting material is larger than the communication holes provided in the filtration device.

3. The algae culture apparatus according to claim 1 or 2, wherein the filtration device is configured so that at least a part of the filtration device is changeable.

4. The algae culture apparatus according to any one of claims 1 to 3, wherein the culture water supplied to the storage device is supplied to the culture water production area.

5. The algae culture apparatus according to any one of claims 1 to 4, wherein at least one of the culture water production area and the culture area is surrounded by the filtration device.

Images