Phytoplankton growth apparatus and phytoplankton growth method

Abstract

[Problem] To provide a technique whereby phytoplankton can be caused to proliferate in a smaller area than by the conventional technique. [Solution] A device for proliferation of phytoplankton, the device comprising a circulation unit which extends in the vertical direction and in which a medium and phytoplankton circulate, and a force feeding unit that is connected to the circulation unit and force-feeds the medium and the phytoplankton upward, the circulation unit having a cylindrical outer wall part that transmits light, and a plurality of flange parts that are layered on the inner side of the outer wall part and lower the medium and phytoplankton while causing the medium and phytoplankton to accumulate, and the plurality of flange parts each including a discoid upper structure and a discoid lower structure that is positioned such that an interval is opened between the upper structure and the lower structure, and the flange parts being formed by layering of the upper structure and the lower structure on the inside of the outer wall part.

Description

Technical Field

[0001] The present invention relates to a phytoplankton growth apparatus and a phytoplankton growth method.

Background Art

[0002] As a technology related to the growth of phytoplankton, for example, there is the technology described in Patent Document 1. Patent Document 1 describes that a floating body is installed on the sea surface or in the sea of an artificial upwelling sea area where a structure is provided on the seabed to artificially generate upwelling, and a phytoplankton growth material made of a glassy material containing divalent iron is attached to the floating body. Further, Patent Document 2 describes an apparatus having a flow path passing through a bioreactor for continuously flowing a suspension containing algae in the presence of light.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Phytoplankton are photosynthetic microorganisms that exist in the photic zone such as the surface of the sea or lake. Sufficient sunlight, appropriate water temperature, appropriate water flow, and abundant nutrients are required for the growth of phytoplankton. In addition, a considerable area is required to grow phytoplankton in large quantities. As a conventional technique for growing phytoplankton in large quantities, there is a technique of providing a growth pond or tank and circulating a culture medium and phytoplankton in the growth pond or tank. However, conventional growth ponds are circular growth ponds with a diameter of several meters to several tens of meters or rectangular ponds partitioned in a maze pattern. Also, conventional tanks are transparent tanks with a diameter of several meters to several tens of meters. That is, in the conventional technique for growing phytoplankton in large quantities, it is necessary to secure a flat area of a considerable size. For example, a large flat area that can obtain sufficient sunlight originally has a high land use value, and high profitability is required from the perspective of land use efficiency. On the other hand, since the growth of phytoplankton is not so profitable compared to other land use methods, it has been a fundamental cause that presses the profitability of the business. From this perspective, it is required that the area required for the facility can be as small as possible and can be installed even in a place with a low land use value. Also, for example, in the technique described in Patent Document 2, since the bioreactor has a planar structure, there is a concern that the flow path may be blocked due to the adhesion of algae inside.

[0005] In view of the above problems, an object of the present invention is to provide a technique capable of growing phytoplankton in a smaller area than conventional ones.

Means for Solving the Problems

[0006] To solve the above problems, in the present invention, the culture medium and phytoplankton are pumped upward, the culture medium and phytoplankton are blocked from the outside world, and while allowing light to pass through, the culture medium and phytoplankton are allowed to stay and descend, and the culture medium and phytoplankton are circulated.

[0007] Specifically, the present invention relates to a phytoplankton growth device, which includes a circulation part that extends in the vertical direction and in which a culture medium and phytoplankton circulate, and a pumping part that is connected to the circulation part and pumps the culture medium and phytoplankton upward. The circulation part has an outer wall part that transmits light, and a flange part laminated inside the outer wall part, the flange part including a plurality of flange parts that lower while retaining the culture medium and phytoplankton.

[0008] In the phytoplankton growth device according to the present invention, since the circulation part extends in the vertical direction, phytoplankton can be grown in a small area as compared with conventional growth ponds and tanks. Further, in the phytoplankton growth device according to the present invention, since the culture medium and phytoplankton are covered with the outer wall part that transmits light, sufficient sunlight can be provided to the phytoplankton. Further, by blocking the culture medium and phytoplankton from the outside world with the outer wall part, the influence from the outside world, such as rainfall, dust, mixing of impurities such as insects, and evaporation to the atmosphere, can be suppressed. Further, by blocking the culture medium and phytoplankton from the outside world, it becomes easier to ensure an appropriate water temperature and abundant nutrients. Further, the culture medium and phytoplankton are pumped upward by the pumping part and descend while passing through the laminated flange parts. In other words, the culture medium and phytoplankton descend slowly while staying. That is, an appropriate water flow is given to the culture medium and phytoplankton. In other words, an excessive load due to water pressure is not applied to the culture medium and phytoplankton. The phytoplankton grows and reproduces while performing photosynthesis by sufficient sunlight and appropriate water flow. In the phytoplankton growth device according to the present invention, the jaw part can be disk-shaped. By making the jaw part disk-shaped, the culture medium and phytoplankton descend while spreading over the disk-shaped jaw part. In other words, since sufficient space is secured in the flow path through which the culture medium and phytoplankton flow, the culture medium and phytoplankton are less likely to be clogged.

[0009] The phytoplankton that can be grown in the phytoplankton growth device according to the present invention may be any microorganism that performs photosynthesis. Examples of phytoplankton include marine phytoplankton and freshwater diatoms. Since phytoplankton can be grown in a smaller area than before, the equipment area required for the phytoplankton growth business can be significantly reduced, improving land use efficiency. In addition, since the equipment can be installed even on a small, flat area, the constraints on the location for conducting the phytoplankton growth business are minimized. As a result, linear scalability of the phytoplankton growth business can be achieved.

[0010] Here, the phytoplankton growth device according to the present invention may further include a storage unit that is connected to a circulation unit and stores a culture medium and phytoplankton, a separation unit that is provided in the storage unit and separates the phytoplankton grown by circulating through the circulation unit from the culture medium, and a bubble unit that applies bubbles to the separation unit to suppress clogging.

[0011] The storage unit stores phytoplankton and a culture medium. The phytoplankton includes phytoplankton larvae, growing phytoplankton, and grown phytoplankton. The storage unit may store these phytoplankton separately. The phytoplankton growth device according to the present invention can harvest the grown phytoplankton by including a separation unit. The grown phytoplankton separated by the separation unit can be sent out to the outside together with the culture medium. The storage unit can be replenished with a new culture medium according to the harvested phytoplankton and culture medium sent out to the outside. The new culture medium can be obtained by removing impurities from the culture medium sent out to the outside and adding nutrient salts with solid minerals.

[0012] When growing phytoplankton in conventional growth ponds or tanks, in any method, due to the structure of the mechanism, it was necessary to divide the culture medium into certain management units and perform batch processing. Therefore, for the growth of phytoplankton, a certain period of time is required from immediately after initially introducing the culture medium and larvae as materials until harvesting. In conventional growth ponds and tanks, it was not possible to simultaneously perform the initial introduction and harvesting in one management unit. In conventional growth ponds and tanks, in order to achieve continuous production, it was only possible to scale up and integrate a large number of batch processing management units to pseudo-realize continuous production. However, when scaling up, the quality slightly differed from batch to batch, making it difficult to ensure uniform product quality. To ensure uniform product quality, detailed quality control processes for individual batches and process integration technologies between multiple batch processes are indispensable, and there were limitations in improving labor efficiency. In the phytoplankton growth device according to the present invention, by providing a separation unit, it becomes possible to harvest the grown phytoplankton. In addition, in the storage unit, a new culture medium can be replenished according to the harvested phytoplankton sent out externally and the culture medium. That is, in the phytoplankton growth device according to the present invention, the initial introduction and harvesting can be simultaneously performed in one management unit. Therefore, continuous production of phytoplankton becomes possible, and the efficiency of continuous production can be improved. In addition, uniform product quality can be ensured.

[0013] Moreover, the phytoplankton growth device according to the present invention may further include at least one of a light source unit connected to the circulation unit and supplying light to the culture medium and phytoplankton, and a heat source unit connected to the circulation unit and supplying heat to the culture medium and phytoplankton.

[0014] By providing the light source unit, it becomes possible to adjust the supply of light. For example, it is possible to promote the growth of phytoplankton at night. In addition, by providing the heat source unit, temperature adjustment becomes possible. For example, it is also possible to grow phytoplankton in cold regions in winter. Moreover, since it becomes possible to adjust the supply amount of light and the temperature, uniform product quality can be ensured.

[0015] In addition, the present invention relates to a phytoplankton growth device, which includes a circulation part that extends in the vertical direction and in which a culture medium and phytoplankton circulate, and a pumping part that is connected to the circulation part and pumps the culture medium and phytoplankton upward. The circulation part has a cylindrical outer wall part that transmits light, and a flange part laminated inside the outer wall part, the flange part including a plurality of flange parts that lower while retaining the culture medium and phytoplankton. The plurality of flange parts include a disk-shaped upper structure body and a disk-shaped lower structure body arranged at an interval from the upper structure body, and the phytoplankton growth device can be configured by laminating the upper structure body and the lower structure body inside the outer wall part.

[0016] In other words, the phytoplankton growth device according to the present invention has a double structure in which the laminated flange parts include a disk-shaped upper structure body and a disk-shaped lower structure body. The disk-shaped upper structure body and the disk-shaped lower structure body can be configured to be separable, but may also be integrally configured. Since the laminated flange parts of the phytoplankton growth device according to the present invention have a double structure, the culture medium and phytoplankton descend more slowly while staying as compared with the case of not having a double structure. That is, a more appropriate water flow is given to the culture medium and phytoplankton. In addition, in the phytoplankton growth device according to the present invention, since the culture medium and phytoplankton descend while diffusing through the disk-shaped flange parts, in other words, since sufficient space is secured in the flow path through which the culture medium and phytoplankton flow, the culture medium and phytoplankton are less likely to become clogged. Note that since the circulation part of the phytoplankton growth device according to the present invention extends in the vertical direction, it has the same effects as the invention described above, such as being able to grow phytoplankton in a small area as compared with conventional growth ponds and tanks, but detailed description thereof will be omitted.

[0017] In addition, the upper structure body may be inclined outward so that the outer edge of the upper surface is lower than the central part, and may have a step part on the upper surface to suppress the descent of the culture medium and phytoplankton. The lower structure body may be inclined inward so that the central part of the upper surface is lower than the outer edge part, and may have an opening near the central part to guide the culture medium and phytoplankton to the upper structure body of the lower layer.

[0018] Since the upper structure has a stepped portion on its upper surface, the descending speeds of the culture medium and phytoplankton can be suppressed. Also, since the lower structure has an opening portion, the culture medium and phytoplankton can be guided to the central portion of the upper structure in the lower layer. That is, in the phytoplankton growth apparatus according to the present invention, the culture medium and phytoplankton descend while diffusing from the central portion to the outer edge portion of the upper structure. At this time, the descending speed is suppressed by the stepped portion. Then, the culture medium and phytoplankton descend while being collected from the outer edge portion to the central portion of the lower structure. Note that a stepped portion similar to that of the upper structure may be provided on the upper surface of the lower structure. As an example, the stepped portion can be a horizontal stepped portion having a horizontal upper surface.

[0019] Further, the phytoplankton growth apparatus according to the present invention further includes a light source unit connected to the circulation unit and supplying light to the culture medium and phytoplankton. The plurality of jaws are made of a member that transmits light, and the light source unit can adjust at least one of a frequency that specifies the color of the light to be supplied and a pulse frequency that specifies the frequency of the light to be supplied according to the characteristics of the phytoplankton to be grown.

[0020] By configuring the plurality of jaws with members that transmit light, sufficient sunlight can be given to the phytoplankton. Also, by making it possible to adjust at least one of a frequency that specifies the color of the light to be supplied and a pulse frequency that specifies the frequency of the light to be supplied according to the characteristics of the phytoplankton to be grown, the efficiency of the light to be supplied can be improved.

[0021] Here, the present invention may be specified as a method for growing phytoplankton. For example, the present invention is a method for growing phytoplankton, which includes a circulation step of circulating the culture medium and phytoplankton in the vertical direction, and a pumping step of pumping the culture medium and phytoplankton upward while performing the circulation step. In the circulation step, the culture medium and phytoplankton are blocked from the outside, and while transmitting light, the culture medium and phytoplankton are allowed to descend while being retained.

[0022] According to the method for growing phytoplankton according to the present invention, phytoplankton can be grown in a smaller area compared to conventional growth ponds and tanks. Further, according to the method for growing phytoplankton according to the present invention, it is possible to suppress the influence from the outside, such as the mixing of impurities such as rainfall, dust, and insects, evaporation into the atmosphere, etc., and to give sufficient sunlight to the phytoplankton. Also, by blocking the medium and phytoplankton from the outside, it becomes easier to ensure an appropriate water temperature and abundant nutrients. Furthermore, since the medium and phytoplankton slowly descend while staying, an appropriate water flow is given to the medium and phytoplankton. In other words, an excessive load due to water pressure is not applied to the medium or phytoplankton. The phytoplankton can grow and reproduce while performing photosynthesis with sufficient sunlight and an appropriate water flow.

Effects of the Invention

[0023] According to the present invention, it is possible to provide a technique for growing phytoplankton in an area smaller than before.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0025] Next, embodiments of the present invention will be described with reference to the drawings. The following description is illustrative, and the present invention is not limited to the following content.

[0026] <First Embodiment> <Configuration of Phytoplankton Growth Device> FIG. 1 shows the overall configuration of a phytoplankton growth device according to the first embodiment. FIG. 2 shows an enlarged view of the circulation section in the phytoplankton growth device according to the first embodiment. The phytoplankton growth device 100 extends in the vertical direction and includes a circulation section 1 in which a medium and phytoplankton circulate, a circulation pump 12 connected to the circulation section 1 for pumping the medium and phytoplankton upward, a storage section 2 for storing phytoplankton, and a water supply section 5 for supplying water. The phytoplankton grown in the phytoplankton growth device 100 according to the first embodiment may be any microorganism that performs photosynthesis. Examples of phytoplankton include marine phytoplankton and freshwater diatoms.

[0027] <Configuration of Circulation Section> The circulation section 1 includes a plurality of stacked disk-shaped stackers 9, an internal circulation pipe 7 passing through the center of the stacker 9, and a transparent exterior pipe 8 covering the stacker 9 and the internal circulation pipe 7.

[0028] The stacker 9 is an example of the flange portion of the present invention, and is composed of a disk portion 91 and an annular protruding portion 92 provided at the center of the disk portion 91 and protruding upward. The disk portion 91 has its outer peripheral vicinity inclined downward so that phytoplankton can easily descend by gravity. The disk portion 91 may be inclined as a whole such that the outer edge portion is lower from the center (central portion) toward the outer edge portion. Also, when the stackers 9 are stacked in the vertical direction, a space where phytoplankton stays is formed between the disk portion 91 and the disk portion 91. The stacker 9 is made of a transparent resin so that light can pass through. Further, a heater 21 (an example of the heat source portion of the present invention) for supplying heat to the culture medium and phytoplankton is built into the disk portion 91. The number of stacked layers of the stackers 9, in other words, the height of the circulation portion 1, is optimized according to the growth characteristics of the growing phytoplankton. Note that instead of the heater 21, a heat source capable of heating and cooling may be used.

[0029] The internal circulation pipe 7 passes through the center of the stackers 9 stacked in the vertical direction, and the culture medium and phytoplankton flow upward inside. The internal circulation pipe 7 is connected to a circulation pump 12 (an example of the pumping portion of the present invention), and the culture medium and phytoplankton are transported to the topmost portion. The internal circulation pipe 7 is made of a transparent resin so that light can pass through.

[0030] The exterior pipe 8 is an example of the outer wall portion of the present invention, covers the stackers 9 stacked in the vertical direction and the internal circulation pipe 7 passing through the stackers 9, and the culture medium and phytoplankton flow downward inside. The exterior pipe 8 is made of a transparent resin so that light can pass through.

[0031] Illumination 6 is an example of the light source unit of the present invention. It is provided at the top of the phytoplankton growth device 100 and supplies light to the medium circulating in the circulation unit 1 and the phytoplankton when the light supply is insufficient, such as at night. Illumination 6 can adjust the frequency that specifies the color of the light to be supplied and the pulse frequency that specifies the frequency of the light to be supplied according to the characteristics of the phytoplankton to be grown. Illumination 6 may adjust either one of the frequency that specifies the color of the light to be supplied and the pulse frequency that specifies the frequency of the light to be supplied.

[0032] <Circulation pump> The circulation pump 12 is connected to the lower part of the internal circulation pipe 7 and pumps the medium and phytoplankton upward.

[0033] <Storage unit> The storage unit 2 includes a storage layer 3, a separation membrane 11, a phytoplankton outlet 13, a base layer 4, etc. The storage layer 3 stores the medium and phytoplankton that have descended while staying in the outer pipe 8. The storage layer 3 is composed of a storage pipe that communicates with the lower part of the circulation unit 1, in other words, the lower end of the outer pipe 8. A pressure regulating valve 23 is provided at the communication part with the outer pipe 8, and the inflow amount into the storage layer 3 can be adjusted. The storage layer 3 is made of a transparent resin so that light can pass through.

[0034] The separation membrane 11 (an example of the separation unit of the present invention) is provided at the lower part of the storage layer 3 and separates the phytoplankton grown by circulating in the circulation unit 1 from the medium. The separation membrane 11 is composed of a mesh having an aperture (or aperture ratio) capable of capturing the grown phytoplankton. Near the separation membrane 11, a microbubble generator 24 (an example of the bubble unit of the present invention) for suppressing clogging by applying fine bubbles to the separation membrane 11 is provided. The microbubble generator 24 is provided with a valve 25 of the bubble generator for adjusting the supply amount of the bubbles. Instead of the microbubble generator 24, other bubble generators may be used. Also, for example, a vibration device may be provided to apply vibration to the separation membrane 11 to suppress clogging.

[0035] The plankton outlet 13 communicates with the lower part of the storage layer 3 and sends out the grown phytoplankton together with the culture medium to the outside. The plankton outlet 13 is composed of a delivery pipe 26 through which the culture medium and the grown phytoplankton flow, and a delivery valve 27 for adjusting the delivery amount of the culture medium and the grown phytoplankton sent out.

[0036] The base layer 4 is provided at the bottommost part of the phytoplankton growth device 100 and stores the culture medium that has passed through the separation membrane 11 and the larvae of phytoplankton and the growing phytoplankton. The base layer 4 communicates with the lower part of the storage layer 3 and the internal circulation pipe 7 of the circulation part 1. The base layer 4 is composed of a bottomed pipe. In addition, a water supply part 5 is connected to the base layer 4. Further, the base layer 4 is provided with a discharge port 17 for discharging the culture medium in the base layer 4. A drain valve 28 for adjusting the discharge amount is provided at the discharge port 17.

[0037] <Water supply part> The water supply part 5 includes a water supply tank 29, a water supply pump 16, a nutrient filter 14, and a water supply valve 15. The water supply tank 29 stores water added with nutrients (also referred to as nutrient salts). The water can be seawater or fresh water according to the phytoplankton. Also, the water may include the larvae of phytoplankton. The water supply tank 29 communicates with the base layer 4 in order to supply the water added with nutrients to the base layer 4. Nutrients are the nutrients necessary for phytoplankton, and examples include nitrogen, phosphorus, silicon, and trace metals. The water supply pump 16 pumps the water added with nutrients. The water supply valve 15 adjusts the supply amount of the water added with nutrients supplied to the base layer 4. The nutrient filter 14 adjusts the concentration of nutrients.

[0038] <Method for growing phytoplankton> Next, a method for growing phytoplankton will be described. In the following description, a method for growing phytoplankton using the above-described phytoplankton growth apparatus will be described. FIG. 3 shows the flow of the method for growing phytoplankton according to the first embodiment. The method for growing phytoplankton includes a circulation step (S01) of circulating the culture medium and phytoplankton in the vertical direction, and a pumping step (S02) that is performed together with the circulation step and pumps the culture medium and phytoplankton upward.

[0039] The culture medium stored in the base layer 4 and the phytoplankton are pumped by the circulation pump 12. The phytoplankton stored in the base layer 4 are phytoplankton larvae or growing phytoplankton that pass through the separation membrane 11. The culture medium and phytoplankton pumped by the circulation pump 12 pass through the internal circulation pipe 7 of the circulation section 1 and are pushed up to the top of the phytoplankton growth apparatus 100. The culture medium and phytoplankton pushed up to the top pass through the transparent exterior pipe 8 and travel along the disk portions 91 of the plurality of stacked stackers 9, staying and slowly descending by gravity, growing and multiplying while performing photosynthesis. The internal circulation pipe 7 and the stacker 9 are covered with the transparent exterior pipe 8. Therefore, the culture medium and phytoplankton grow and multiply in a state where the influence from the outside, such as the mixing of impurities such as rain, dust, and insects, and evaporation into the atmosphere, is suppressed. When the supply amount of light is insufficient, such as at night, light is supplied by the lighting 6. Also, when temperature adjustment is required, such as in winter, it is heated by the heater 21.

[0040] The culture medium and phytoplankton that have descended inside the outer pipe 8 are stored in the storage layer 3. The inflow amounts of the culture medium and phytoplankton flowing from the outer pipe 8 into the storage layer 3 are adjusted by the pressure regulating valve 23. The culture medium and phytoplankton stored in the storage layer 3 are separated by the separation membrane 11. In the separation membrane 11, the grown phytoplankton are trapped. The growing phytoplankton and the larvae of phytoplankton pass through the separation membrane 11 and flow into the base layer 4. The grown phytoplankton trapped by the separation membrane 11 are sent out to the outside and harvested together with the culture medium through the plankton outlet 13. The sending-out amounts of the culture medium and the grown phytoplankton sent out to the outside are adjusted by the valve 27 for sending. Note that bubbles are applied to the separation membrane 11 by the microbubble generator 24, and clogging of the separation membrane 11 is suppressed.

[0041] The culture medium and phytoplankton that have flowed into the base layer 4 are pumped by the circulation pump 12, pass through the internal circulation pipe 7, are pushed up to the top of the phytoplankton growth device 100, and grow and reproduce while descending inside the outer pipe 8. Note that water with nutrients added is appropriately supplied to the base layer 4 by the water supply section 5.

[0042] <Effect> Since the circulation section 1 of the phytoplankton growth device 100 according to the first embodiment extends in the vertical direction, phytoplankton can be grown in a small area as compared with conventional growth ponds and tanks. Further, in the phytoplankton growth device 100 according to the first embodiment, the culture medium and the phytoplankton are covered with the exterior pipe 8 that transmits light. Further, since the stacker 9 and the internal circulation pipe 7 are made of a transparent resin, sufficient sunlight can be given to the phytoplankton. Further, by blocking the culture medium and the phytoplankton from the outside world with the exterior pipe 8, the influence from the outside world, such as rainfall, dust, mixing of impurities such as insects, and evaporation to the atmosphere, can be suppressed. Further, by blocking the culture medium and the phytoplankton from the outside world, it becomes easier to secure an appropriate water temperature and abundant nutrients. Further, by blocking the culture medium and the phytoplankton from the outside world, it becomes possible to install the phytoplankton growth device 100 in an unstable place such as on the ocean. Further, the culture medium and the phytoplankton are pumped upward by the circulation pump 12 and descend while passing through the stacked stacker 9. In other words, the culture medium and the phytoplankton descend slowly while staying. That is, an appropriate water flow is given to the culture medium and the phytoplankton. In other words, an excessive load due to water pressure is not applied to the culture medium and the phytoplankton. The phytoplankton can grow and reproduce while performing photosynthesis by sufficient sunlight and appropriate water flow. Further, the culture medium and the phytoplankton descend while spreading over the disk-shaped stacker 9. In other words, since sufficient space is secured in the flow path through which the culture medium and the phytoplankton flow, the culture medium and the phytoplankton are less likely to become clogged.

[0043] The grown phytoplankton separated by the separation membrane 11 in the storage unit 2 can be sent out and harvested together with the culture medium. Also, to the base layer 4 of the storage unit 2, according to the harvested phytoplankton and the culture medium, the water supply unit 5 can supply water with nutrients added as a new culture medium. In the phytoplankton growth device 100 according to the first embodiment, the initial input and the harvest can be carried out simultaneously in one management unit. Therefore, continuous production of phytoplankton becomes possible, and the efficiency of continuous production can be improved. Also, uniform product quality can be ensured.

[0044] Also, the phytoplankton growth device 100 according to the first embodiment is equipped with lighting 6, so that the amount of light supplied can be adjusted. As a result, for example, the growth of phytoplankton at night can be promoted. Also, the phytoplankton growth device 100 according to the first embodiment is equipped with a heater 21, so that temperature adjustment becomes possible. As a result, for example, the growth of phytoplankton in cold regions in winter is also possible. Also, since the amount of light supplied and temperature adjustment are possible, uniform product quality can be ensured.

[0045] The phytoplankton that can be grown in the phytoplankton growth device 100 according to the first embodiment may be any microorganism that performs photosynthesis. Since phytoplankton can be grown in a smaller area than before, the facility area required for the phytoplankton growth business can be significantly reduced, improving land use efficiency. Also, since the equipment can be installed even on a small flat area, the constraints on the location for conducting the phytoplankton growth business are minimized. As a result, linear scalability of the phytoplankton growth business can be realized.

[0046] The phytoplankton growth device 100 according to the first embodiment has few restrictions on the installation location, so it can also be installed on the rooftop of a building or on a sloping ground, which was conventionally considered difficult to grow phytoplankton. Also, the phytoplankton growth device 100 according to the first embodiment has few restrictions on the installation location, so it can also be installed in combination with onshore or offshore fishery and aquaculture facilities.

[0047] <Second Embodiment> The phytoplankton growth device 100 according to the second embodiment further includes various sensors 50 and a control device 300 connected to the various sensors 50. FIG. 4 shows a block diagram of the phytoplankton growth device according to the second embodiment. FIG. 4 illustrates the main configuration of the phytoplankton growth device 100 according to the second embodiment, the various sensors 50, and the control device 300. Note that descriptions of configurations similar to those of the phytoplankton growth device 100 according to the first embodiment are omitted.

[0048] The various sensors 50 include a plankton counter 51 that counts the phytoplankton in the storage layer, a transparency meter 52 for the storage layer that measures the transparency in the storage layer 3, a transparency meter 53 for the base layer that measures the transparency in the base layer 4, a sensor 54 for the circulation pump that detects the rotation speed and water flow of the circulation pump 12, a sensor 55 for the water supply pump that detects the rotation speed and water flow of the water supply pump 16, a water level meter 56 for the circulation section that detects the water level in the circulation section 1, a water level meter 57 for the storage layer that detects the water level in the storage layer 3, a water level meter 58 for the base layer that detects the water level in the base layer, a water level meter 59 for the water supply section that detects the water level in the water supply section 5, a salinity meter 60 for the storage layer that detects the salinity concentration in the storage layer 3, a salinity meter 61 for the base layer that detects the salinity concentration in the base layer 4, a thermometer 62 for the outside air temperature that detects the outside air temperature, an illuminometer 63 that detects the external illuminance, a water temperature meter 64 for the storage layer that detects the water temperature in the storage layer 3, and a water temperature meter 65 for the base layer that detects the water temperature in the base layer 4.

[0049] The control device 300 can be configured by a PLC (programmable logic controller), a computer, or the like. As an example, the control device 300 includes a control unit 31, a display unit 34, an operation unit 35, a storage unit 36, and a communication unit 37. The control unit 31 includes a CPU (central processing unit) 32 and a memory 33. The memory 33 can be configured by a storage medium such as a ROM or a RAM. Data such as a control program is stored in the memory 33. The display unit 34 includes, for example, a liquid crystal display device, a plasma display panel, a CRT (Cathode Ray Tube), an electroluminescent panel, or the like. The operation unit 35 includes, for example, a keyboard, a pointing device, a touch panel, operation buttons, or the like. The storage unit 36 includes, for example, an HDD (hard disk drive), an SSD (solid state drive), or the like. The communication unit 37 is exemplified by, for example, a communication module (for example, a network card) that realizes connection to a network.

[0050] The CPU 32 reads the program stored in the memory 33 and controls the phytoplankton growth device 100 based on the information acquired by various sensors. For example, the control unit 31 controls the circulation pump 12, the water supply pump 16, the valve 27 for sending, the drain valve 28, the water supply valve 15, the valve 25 of the bubble generator, the lighting 6, and the heater 21 based on the information detected by at least any one of the sensors such as the plankton counter 51, the transparency meter 52 of the storage layer, the transparency meter 53 of the base layer, the sensor 54 of the circulation pump, the sensor 55 of the water supply pump, the water level meter 56 of the circulation section, the water level meter 57 of the storage layer, the water level meter 58 of the base layer, the water level meter 59 of the water supply section, the salinity meter 60 of the storage layer, the salinity meter 61 of the base layer, the thermometer 62 of the outside air temperature, the illuminance meter 63, the water temperature meter 64 of the storage layer, and the water temperature meter 65 of the base layer.

[0051] According to the phytoplankton growth device 100 according to the second embodiment, in addition to the effects of the phytoplankton growth device 100 according to the first embodiment, the growth of phytoplankton and the labor saving in the growth of phytoplankton can be realized by the control by the control device 300.

[0052] <Third Embodiment> Next, the phytoplankton growth apparatus according to the third embodiment will be described. The configuration of the stacker 9 in the phytoplankton growth apparatus according to the third embodiment is different from that of the phytoplankton growth apparatus according to the first and second embodiments. Since the other configurations are the same as those of the phytoplankton growth apparatus according to the first and second embodiments, the description thereof will be omitted.

[0053] FIG. 5 shows an enlarged view of the circulation part in the phytoplankton growth apparatus according to the third embodiment. FIG. 6 shows a cross-sectional view of the circulation part in the phytoplankton growth apparatus according to the third embodiment.

[0054] The stacker 9 (hereinafter also referred to as the stacker 9 according to the third embodiment) in the phytoplankton growth apparatus according to the third embodiment is an example of the flange part of the present invention. The stacker 9 according to the third embodiment has a double structure including a disk-shaped upper structure 9a and a disk-shaped lower structure 9b arranged at a distance from the upper structure 9a, and the upper structure 9a and the lower structure 9b are laminated inside the outer pipe 8. The stacker 9 according to the third embodiment has a disk-shaped upper structure 9a and a disk-shaped lower structure 9b that can be separated, but they may also be integrally configured.

[0055] The upper structure 9a includes a disk part 9a1 and an annular protruding part 9a2 provided at the center of the disk part 9a1 and protruding upward. The upper surface of the upper structure 9a3 is inclined outward so that the outer edge is lower than the central part. Further, a step part 9a3 for suppressing the descent of the culture medium and phytoplankton is provided on the upper surface of the upper structure 9a. The step part 9a is composed of a plurality of continuous horizontal parts and vertical parts.

[0056] The lower structure 9b is formed with an outer diameter larger than that of the upper structure 9a so as to receive the culture medium and phytoplankton descending from the outer edge of the upper structure 9a. Also, the upper surface of the lower structure 9b is inclined inward so that the central portion is lower than the outer edge portion. Further, an opening 9b3 for guiding the culture medium and phytoplankton to the upper structure 9a in the lower layer is provided near the central portion of the lower structure 9b. The stacker 9 according to the third embodiment is also made of a transparent resin so that light can pass through. Note that heaters 21 (an example of the heat source unit of the present invention) similar to those in the first embodiment may be incorporated in the disk portion 9a1 of the upper structure 9a and the disk portion 9b1 of the lower structure 9b. Instead of the heater 21, a heat source capable of heating and cooling may be used. The number of stacked layers of the stacker 9, in other words, the height of the circulation unit 1 is optimized according to the growth characteristics of the growing phytoplankton.

[0057] The method for growing phytoplankton using the phytoplankton growth apparatus according to the third embodiment is basically the same as the method for growing phytoplankton using the phytoplankton growth apparatus according to the first embodiment. Also in the method for growing phytoplankton using the phytoplankton growth apparatus according to the third embodiment, the culture medium and phytoplankton pushed up to the topmost part descend slowly by gravity while staying, passing through the disk portions 91 of the plurality of stacked stackers 9 in the transparent outer pipe 8, and grow and reproduce while performing photosynthesis. The stacker 9 according to the third embodiment has a double structure including a disk-shaped upper structure 9a and a disk-shaped lower structure 9b arranged at an interval from the upper structure 9a. Therefore, in the phytoplankton growth apparatus according to the third embodiment, compared with the phytoplankton growth apparatus according to the first embodiment, the culture medium and phytoplankton descend more slowly and grow and reproduce while performing photosynthesis. Specifically, the culture medium and phytoplankton descend while diffusing from the central portion of the upper structure 9a toward the outer edge portion. At this time, the descending speed is suppressed by the step portion 9a3. The culture medium and phytoplankton descending from the outer edge portion of the upper structure 9a are received at the outer edge portion of the lower structure 9b and descend while being collected from the outer edge portion of the lower structure 9b toward the central portion.

[0058] In the phytoplankton growth device according to the third embodiment, since the stacker 9 to be stacked has a double structure, the culture medium and the phytoplankton descend more slowly while staying as compared with the case where they do not have a double structure. Since the upper structure 9a has a stepped portion 9a3 on the upper surface, the descending speed of the culture medium and the phytoplankton can be suppressed. Further, since the lower structure 9b has an opening 9b3, the culture medium and the phytoplankton can be guided to the central portion of the upper structure 9a in the lower layer. That is, in the phytoplankton growth device according to the third embodiment, the culture medium and the phytoplankton descend while diffusing from the central portion of the upper structure 9a toward the outer edge portion. At this time, the descending speed is suppressed by the stepped portion 9a3. Then, the culture medium and the phytoplankton descend while being collected from the outer edge portion of the lower structure 9b toward the central portion. That is, an appropriate water flow is further applied to the culture medium and the phytoplankton. Further, in the phytoplankton growth device according to the third embodiment, since the culture medium and the phytoplankton descend while diffusing, in other words, since sufficient space is secured in the flow path through which the culture medium and the phytoplankton flow, the culture medium and the phytoplankton are less likely to be clogged. Note that the phytoplankton growth device according to the third embodiment has the same effects as the phytoplankton growth device according to the first embodiment, such as being able to grow phytoplankton in a small area as compared with conventional growth ponds and tanks, because the circulation unit 1 extends in the vertical direction, but detailed description thereof is omitted.

[0059] As described above, the embodiments of the present invention have been explained. However, the phytoplankton growth apparatus and the phytoplankton growth method according to the present invention can be variously modified without departing from the gist of the present invention. Further, the necessity of the present invention is driven by the demand for phytoplankton. The demand for phytoplankton is roughly classified into direct demand for directly using phytoplankton such as chlorella and euglena (green algae) as they are or as processed raw materials, and indirect demand for supplying feed for aquaculture of seafood such as abalone, which has become popular worldwide in recent years. There are thousands of species of phytoplankton, and although their ecologies and growth environments are diverse, their functions such as the nutrients contained therein and the usability as fuel are also diverse. In direct demand, various functions are directly utilized as products. In indirect demand, the main focus is on ensuring food safety and supply stability, and the functions of phytoplankton are indirectly utilized through seafood. The present invention can provide value to both of them.

Explanation of Signs

[0060] 1 ··· Circulation section 2 ··· Storage section 3 ··· Storage layer 4 ··· Base layer 5 ··· Water supply section 6 ··· Lighting 7 ··· Internal circulation pipe 8 ··· Exterior pipe 9 ··· Stacker 11 ··· Separation membrane 12 ··· Circulation pump 13 ··· Phytoplankton outlet 14 ··· Nutrient filter 15 ··· Water supply valve 16 ··· Water supply pump 17 ··· Drain outlet 21 ··· Heater 23 ··· Pressure regulating valve 24 ··· Microbubble generator 25 ··· Valve of bubble generator 26 ··· Pipe for sending out 27 ··· Valve for sending out 28 ··· Drain valve 29 ··· Water supply tank 31 ··· Control unit 50 ··· Various sensors 91 ··· Disk part 92 ··· Protrusion 100 ··· Phytoplankton growth device 300 ··· Control device

Claims

1. A phytoplankton growth device comprising: a circulation section that extends vertically and in which a culture medium and phytoplankton circulate; a pumping section connected to the circulation section for pumping the culture medium and phytoplankton upward. The circulation section has a cylindrical outer wall portion that transmits light, and a flange portion laminated inside the outer wall portion, the flange portion including a plurality of flange portions for causing the culture medium and phytoplankton to descend while retaining them. The plurality of jaw portions include a disk-shaped upper structure and a disk-shaped lower structure arranged at an interval from the upper structure, and the upper structure and the lower structure are laminated inside the outer wall portion to constitute a phytoplankton growth device.

2. The upper structure has an upper surface that slopes outward so that the outer edge is lower than the central portion, and a stepped portion on the upper surface for suppressing the descent of the culture medium and phytoplankton. The lower structure has an upper surface that slopes inward so that the central portion is lower than the outer edge portion, and an opening near the central portion for guiding the culture medium and phytoplankton to the upper structure of the lower layer. The phytoplankton growth device according to claim 1.

3. The device further comprises a light source section connected to the circulation section for supplying light to the culture medium and phytoplankton. The plurality of jaw portions transmit light. The light source section can adjust at least one of a frequency for specifying the color of the light to be supplied and a pulse frequency for specifying the frequency of the light to be supplied according to the characteristics of the phytoplankton to be grown. The phytoplankton growth device according to claim 1 or 2.

4. A method for growing phytoplankton, comprising: a circulation step of circulating a culture medium and phytoplankton in the vertical direction; a pumping step of pumping the culture medium and phytoplankton upward, which is performed together with the circulation step. In the circulation step, a cylindrical outer wall portion that transmits light blocks the culture medium and phytoplankton from the outside, and while transmitting light, the culture medium and phytoplankton are caused to descend while being retained by a plurality of jaw portions including a disk-shaped upper structure and a disk-shaped lower structure arranged at an interval from the upper structure, and the upper structure and the lower structure are laminated inside the outer wall portion. A method for growing phytoplankton.

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