Carbon dioxide reduction and utilization systems in sewage treatment plants

Abstract

A system for reducing and utilizing carbon dioxide in a sewage treatment plant is disclosed, which enables CCU (carbon capture and utilization) at the sewage treatment plant, a source of carbon dioxide emissions, and also achieves water purification by using treated wastewater from the sewage treatment plant as an algae culture medium. [Solution] The disclosed carbon dioxide reduction and utilization system for a sewage treatment plant is characterized by including: a sewage treatment device that purifies incoming sewage in multiple stages and generates carbon dioxide during the treatment process; an algae cultivation device that cultivates and produces microalgae using the carbon dioxide generated in the sewage treatment device and treated sewage water; a gas collection device that collects carbon dioxide generated in the sewage treatment device; and a nanobubble device that receives treated sewage water treated in the sewage treatment device and carbon dioxide collected from the gas collection device, and supplies treated sewage water in which carbon dioxide has been dissolved in nanobubbles to the algae cultivation device.

Description

[Technical Field]

[0001] The present invention relates to a carbon dioxide reduction and utilization system, and more specifically, to a carbon dioxide reduction and utilization system in a sewage treatment plant that uses carbon dioxide generated in the biological reaction tank of the sewage treatment plant as a carbon dioxide supply source. Although the amount of carbon dioxide supplied is less than that supplied from the exhaust gas of existing thermal power plants, this system achieves CCU (Carbon Capture Utilization) at the sewage treatment plant, which is a source of carbon dioxide emissions, and also achieves water purification by using treated wastewater from the sewage treatment plant as an algae culture medium. [Background technology]

[0002] Generally speaking, among carbon dioxide removal technologies, direct air capture (DAC) is a method of extracting and removing carbon dioxide from the air using chemical reactions. More specifically, it is a technology that brings air into contact with a chemical substance, causing the chemical substance to selectively react with carbon dioxide and capture it.

[0003] The carbon collected in this way is sent to a desorption tower where it is separated into high-concentration carbon, which can then be injected and stored underground, or reused to make concrete or plastics.

[0004] In order to solve the climate crisis and move towards a net-zero society with zero gas emissions, the potential of such DACs is enormous.

[0005] According to the International Energy Agency's (IEA) Net Zero Emissions by 2050 scenario (an energy and climate scenario outlining a path to achieving carbon neutrality by 2050), DAC technology must be able to capture approximately 85 million tons of carbon by 2030 and around 980 million tons by 2050.

[0006] Today, the amount of carbon captured using DAC technology does not reach 10,000 tons. Furthermore, current DAC technology is very expensive and energy-intensive, as considerable heat and electricity are required to capture air and filter out carbon.

[0007] Today, removing one billion tons of carbon dioxide from the atmosphere using DAC technology would require an enormous amount of energy—10% of the world's total energy consumption.

[0008] For DAC technology to establish itself as a true climate crisis solution, it must be powered by low-carbon or carbon-free energy sources as the technology develops. Furthermore, current cost estimates range from approximately $150 to over $600 per ton of carbon removed (approximately 200,000 to 800,000 won at today's exchange rate). While this is a fairly broad estimate and costs are expected to decrease significantly as the technology improves and more projects are implemented, it is clear that widespread commercialization will still take time.

[0009] On the other hand, there are 40,000 known species of algae, and as organisms with the longest history on Earth, they can survive in a variety of environments. Algae are often known to cause problems due to abnormal proliferation in relation to water pollution, and commercially, they are attracting attention as a source of high value-added substances such as health supplements, natural pigments, pharmaceuticals, biochemicals, and animal feed. More recently, they have attracted attention as a way to reduce carbon dioxide emissions and produce alternative energy such as biodiesel, bioethanol, and hydrogen in relation to global environmental and climate change issues.

[0010] In algal cultivation, nutrients such as nitrogen and phosphorus are used to synthesize cellular components, while carbon dioxide is essential for photosynthesis and growth through carbon supply.

[0011] Carbon Capture Utilization and Storage (CCUS) using microalgae cultivation primarily aims to utilize carbon dioxide (CO2) emitted as exhaust gas (flue gas) from thermal power plants. Therefore, nitrogen, phosphorus, and other nutrients necessary for algae cultivation must be supplied separately.

[0012] One strategy to overcome these shortcomings was to use wastewater as a culture medium, thereby simultaneously cultivating microalgae and treating wastewater (phycoremediation) by consuming the components within the wastewater without separately supplying the nutrients necessary for cultivation. However, since power plants and wastewater treatment facilities are generally not located in the same place or in close proximity, it was practically difficult to use exhaust gas from thermal power plants as a carbon dioxide (CO2) source in the technology of using wastewater from sewage treatment plants as a culture medium for algae cultivation. In addition, when wastewater was used directly as a culture medium, the algae frequently died due to the high concentrations of nitrogen (N) and phosphorus (P). [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] Korean Registered Patent Publication No. 10-1423285 [Patent Document 2] Korean Registered Patent Publication No. 10-1072844 [Patent Document 3] Korean Registered Patent Publication No. 10-1122986 [Overview of the project] [Problems that the invention aims to solve]

[0014] The present invention was devised to solve the above-mentioned conventional problems. By using carbon dioxide generated in the biological reaction tank of a sewage treatment facility as a carbon dioxide supply source, although the amount is less compared to the supply of carbon dioxide from the exhaust gas of a conventional thermal power plant, it realizes CCU (Carbon Capture Utilization) in the sewage treatment facility, which is a carbon dioxide emission source, and enables water purification by using the treated sewage water of the sewage treatment facility as an algae culture medium. The purpose is to provide a carbon dioxide reduction and utilization system in a sewage treatment plant.

[0015] In addition, the present invention supplies carbon dioxide and treated sewage water generated in a sewage treatment plant to an algae culture device. By nano-bubbling and dissolving carbon dioxide in the treated sewage water and supplying it as an algae culture medium, the residence time of carbon dioxide in the algae culture device is improved, thereby promoting the algae growth rate and facilitating the management of the algae culture device. Another object is to provide a carbon dioxide reduction and utilization system in a sewage treatment plant.

[0016] However, the object of the present invention is not limited thereto, and of course, objects or effects that can be grasped from the problem-solving means and embodiments even without explicit mention are also included.

Means for Solving the Problems

[0017] The carbon dioxide reduction and utilization system in a sewage treatment plant of the present invention for achieving the above object includes an algae culture device that cultivates and produces microalgae using carbon dioxide generated in a sewage treatment device and treated sewage water, a gas collection device that collects carbon dioxide generated in the sewage treatment device, the treated sewage water treated in the sewage treatment device, and a nano-bubble device that supplies the treated sewage water in which carbon dioxide is nano-bubbled and dissolved to the algae culture device.

[0018] The gas collection device can be configured to collect carbon dioxide generated in the primary sedimentation tank and the biological reaction tank of the sewage treatment device and supply it to the nanobubble device.

[0019] The nanobubble device is composed of an ejector, into which the sewage treatment water is supplied and transferred and discharged at high speed. Due to the negative pressure generated by the flow of the sewage treatment water during transfer, carbon dioxide is inhaled from the gas collection device, merged with the sewage treatment water and discharged. It includes a bubble-treated water generation unit, a treatment water transfer pump connected to the bubble-treated water generation unit to generate the flow of the sewage treatment water, a bubble splitter connected to the bubble-treated water generation unit via the treatment water transfer pump, where the sewage treatment water containing carbon dioxide bubbles is supplied from the bubble-treated water generation unit and the carbon dioxide bubbles are crushed to form carbon dioxide nanobubbles, and a nozzle unit connected to the bubble splitter and provided in the algae culture device to discharge the sewage treatment water containing the carbon dioxide nanobubbles into the algae culture device.

[0020] The bubble splitter includes a splitter chamber part that provides a bubble crushing space into which the sewage treatment water flows and the carbon dioxide bubbles contained in the sewage treatment water are divided, an inflow pipe part connected to the treatment water transfer pump and vertically arranged in the splitter chamber part to form a downward water flow of the sewage treatment water transferred from the treatment water transfer pump, a bubble crushing cup part that is cylindrical with an open top and is provided to surround the inflow pipe part in the splitter chamber part, and the sewage treatment water discharged downward through the inflow pipe part collides to crush the primary bubbles, and an outflow pipe part connected to the nozzle unit and provided in parallel with the bubble crushing cup part inside the splitter chamber part, into which the sewage treatment water discharged upward from the bubble crushing cup part flows and is discharged to the nozzle unit.

[0021] The bubble splitter may be configured to further include a flow path extension that is provided inside the splitter chamber between the bubble-breaking cup and the outflow pipeline, and performs secondary bubble breaking while the treated wastewater discharged upward from the bubble-breaking cup forms a zigzag flow path.

[0022] The flow path extension may further include at least one flow path extension arranged in parallel between the bubble-breaking cup section and the outflow pipeline section.

[0023] The nanobubble device can be configured to have one channel extension to generate treated wastewater containing carbon dioxide nanobubbles of 950 to 1050 nanometers in size and supply it to the algae cultivation device, or to have two channel extensions to generate treated wastewater containing carbon dioxide nanobubbles of 800 to 900 nanometers in size and supply it to the algae cultivation device, or to have three channel extensions to generate treated wastewater containing carbon dioxide nanobubbles of 650 to 750 nanometers in size and supply it to the algae cultivation device.

[0024] The system may further include a culture information monitoring device that calculates and monitors result data, including the growth rate of microalgae, carbon dioxide fixation efficiency, and increase in microalgae biomass, based on the environmental conditions of the algae culture apparatus, through mathematical modeling. [Effects of the Invention]

[0025] As described above, the present invention develops a composite process technology that combines DAC (Direct Air Capture) technology and CCU (Carbon Capture and Utilization) technology, thereby improving the high cost structure which is currently a limitation of DAC technology, and securing a technology that can be applied not only to sewage treatment plants but also to livestock wastewater treatment facilities, food wastewater treatment facilities, and other applications.

[0026] Furthermore, regarding the difficult task of algae recovery in conventional algae cultivation tanks, applying a sludge extraction method that utilizes the SRT (Sludge Retention Time) process used in sewage treatment processes allows for efficient algae recovery, effectively solving problems that pose obstacles in the field.

[0027] Furthermore, while various bubble generators suitable for air, oxygen, and ozone have been developed, there are no bubble generators for carbon dioxide. Since carbon dioxide is a polar gas with a high dissolution rate, and it is difficult to reduce the bubble size using pressure differences, this invention applies a splitter-type nanobubble generator to generate nanometer-sized carbon dioxide microbubbles. This significantly improves the residence time in algae culture tanks, allowing for smoother and more effective carbon supply to algae, thereby increasing the growth rate of algae and enhancing the productivity of alternative energy utilizing algae.

[0028] Furthermore, since this invention reuses wastewater discharged from sewage by introducing it into an algae cultivation tank, it can increase the reuse rate of sewage and has the effect of preventing eutrophication of rivers during the summer.

[0029] Furthermore, the present invention has the effect of laying the foundation for policies that respond to the strengthening of international environmental regulations, such as the reduction of greenhouse gases, the promotion of CDM projects, and the trading of greenhouse gas emission rights.

[0030] Furthermore, the diverse and beneficial advantages and effects of the present invention are not limited to those described above and will become more readily apparent in the process of describing specific embodiments of the present invention. [Brief explanation of the drawing]

[0031] [Figure 1] This is a conceptual diagram of a carbon dioxide reduction and utilization system in a sewage treatment plant according to the first embodiment of the present invention. [Figure 2] This is a block diagram showing a carbon dioxide reduction and utilization system in a sewage treatment plant according to the first embodiment of the present invention. [Figure 3]This figure specifically illustrates the nanobubble apparatus of the present invention. [Figure 4] This figure shows various other forms of bubble splitters in the nanobubble device of the present invention. [Figure 5] This figure shows another embodiment of the nanobubble apparatus of the present invention. [Figure 6] This is a block diagram showing a carbon dioxide reduction and utilization system in a sewage treatment plant according to the second embodiment. [Figure 7] Figure 6 is a block diagram showing the specific configuration of the culture information monitoring device. [Modes for carrying out the invention]

[0032] The above-described objects, other objects, features, and advantages of the present invention will be readily apparent from the following preferred embodiments relating to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments presented herein are provided so that the disclosed content may be thorough and complete, and so as to fully convey the idea of ​​the invention to those skilled in the art.

[0033] In this specification, when any component is referred to as being on another component, it means that it may be formed directly on the other component or a third component may be interposed between them. Furthermore, in the drawings, the thickness of the components is exaggerated for the sake of effective illustration of the technical content.

[0034] In describing the following specific embodiments, various specific details have been created to further explain and aid understanding of the invention. However, as the invention is understood, those with knowledge of the art will recognize that it can be used without these specific details. In any example, it should be noted in advance that parts of the invention that are well known and not significantly related to the invention are omitted to prevent confusion in the description of the invention without special reason.

[0035] The carbon dioxide reduction and utilization system in a wastewater treatment plant according to the first embodiment of the present invention will be described below with reference to Figures 1 to 4.

[0036] The carbon dioxide reduction and utilization system for wastewater treatment plants of the present invention is configured to include a wastewater treatment device 10, an algae cultivation device 20, a gas collection device 30, and a nanobubble device 40.

[0037] The sewage treatment device 10 is configured to include a grit tank 11, a primary sedimentation tank 12, a biological reaction tank 13, a final sedimentation tank 14, a total phosphorus treatment facility 15, and a disinfection facility 16.

[0038] The sedimentation basin 11 is configured to receive raw sewage, remove suspended solids from the incoming sewage, and supply the treated water to the primary sedimentation basin 12.

[0039] The primary sedimentation tank 12 is configured to remove suspended solids from the primary treated water flowing in from the sedimentation tank 11 by gravity sedimentation, supply the secondary treated water to the biological reaction tank 13, and reduce the contamination load in the biological reaction tank 13.

[0040] The biological reaction tank 13 is configured to receive secondary treated water flowing in from the primary sedimentation tank 12, remove a certain amount of organic matter and nutrients present in the sewage using microorganisms, and then supply tertiary treated water to the final sedimentation tank 14.

[0041] The final sedimentation tank 14 is configured to remove sludge from the tertiary treated water flowing in from the biological reaction tank 13 by gravity sedimentation and to supply the quaternary treated water to the total phosphorus treatment facility 15.

[0042] The total phosphorus treatment facility 15 is configured to coagulate the total phosphorus contained in the quaternary treated water flowing in from the final sedimentation tank 14, reduce the total phosphorus concentration by a predetermined amount, and supply the quinary treated water to the disinfection equipment 16.

[0043] The disinfection equipment 16 is configured to disinfect the 5th-stage treated water flowing in from the total phosphorus treatment facility 15 via ultraviolet sterilization and ozone contact reaction, and then discharge the final treated wastewater.

[0044] The final treated wastewater discharged from the disinfection equipment 16 is supplied to the nanobubble device 40, where carbon dioxide is dissolved in the final treated wastewater as nanobubbles and then supplied to the algae cultivation device 20.

[0045] As described above, the sewage treatment device 10 consists of a grit chamber 11, a primary sedimentation chamber 12, a biological reaction tank 13, a final sedimentation chamber 14, a total phosphorus treatment facility 15, and a disinfection facility 16. Each treatment component 11, 12, 13, 14, 15, and 16 can have the same configuration and principle as a typical sewage treatment facility. Furthermore, although it has been described above that the device consists of a grit chamber 11, a primary sedimentation chamber 12, a biological reaction tank 13, a final sedimentation chamber 14, a total phosphorus treatment facility 15, and a disinfection facility 16, it is not limited to this configuration. It can be configured in the same way as a sewage treatment device built in a typical sewage treatment facility that purifies incoming sewage in multiple stages. Moreover, as mentioned above, the sewage treatment device 10 is configured to include a six-stage treatment configuration for raw sewage, but it can also have a configuration that treats sewage in more or fewer treatment steps than six, as is the case with other sewage treatment facilities.

[0046] The algae cultivation apparatus 20 is a device for cultivating microalgae, most of which grow using carbon dioxide, a carbon source, through photosynthesis, and use light as an energy source for photosynthesis.

[0047] In an algal cultivation environment, if the carbon dioxide concentration is insufficient, the rate of photosynthesis slows down, resulting in insufficient carbon supply and reduced growth.

[0048] Furthermore, the algae cultivation apparatus 20 requires nutrients such as nitrogen and phosphorus, and is configured to supply such nutrients.

[0049] The present invention is characterized in that the algae cultivation apparatus 20 is supplied with all the nutrients necessary for algae cultivation, such as nitrogen and phosphorus, and carbon dioxide as a carbon source for algae photosynthesis and growth, from the sewage treatment apparatus 10.

[0050] In particular, the present invention is not a method of independently supplying the final treated wastewater containing nitrogen and phosphorus from the wastewater treatment device 10 and the carbon dioxide collected by the wastewater treatment device 10 to the algae cultivation device 20, but rather is configured such that carbon dioxide, which has been atomized into nanobubbles using a nanobubble device 40, is mixed with the final treated wastewater so that it is dissolved, and then this final treated wastewater containing the nanobubbles of carbon dioxide is supplied to the algae cultivation device 20.

[0051] The gas collection device 30 is configured to collect carbon dioxide generated in the sewage treatment device 10.

[0052] The gas collection device 30 is located above the primary sedimentation tank 12 and the biological reaction tank 13, and is configured to collect carbon dioxide generated in the primary sedimentation tank 12 and the biological reaction tank 13.

[0053] The gas collection device 30 may be configured to include a suction fan (not shown) for drawing in and collecting carbon dioxide generated in the primary sedimentation tank 12 and the biological reaction tank 13.

[0054] The nanobubble device 40 is configured to receive the final treated wastewater treated by the wastewater treatment device 10 and carbon dioxide collected from the gas collection device 30, and to convert the carbon dioxide into nanobubbles in the final treated wastewater before supplying the treated wastewater with dissolved carbon dioxide nanobubbles to the algae cultivation device 20.

[0055] Referring to Figure 3, the nanobubble device 40 is configured to include a bubble treated water generation unit 41, a treated water transfer pump 42, a bubble splitter 43, and a nozzle unit 45.

[0056] The bubble-treated water generation unit 41 consists of an ejector equipped with a treated water inlet 411 connected to the disinfection equipment 16 to which final treated wastewater is supplied, a treated water discharge unit 412 from which the final treated wastewater supplied from the treated water inlet 411 is discharged, and a gas inlet 413 connected to the gas collection device 30 to which carbon dioxide is supplied.

[0057] The bubble-treated water generation unit 41 is connected to the disinfection equipment 16. Final treated wastewater, which has been treated in the wastewater treatment device 10, is supplied through the treated water inlet 411, transported at high speed, and discharged through the treated water discharge unit 412. In this process, the negative pressure generated by the flow of the transported final treated wastewater causes carbon dioxide supplied from the gas collection device 30 to be drawn in through the gas inlet 413. The drawn carbon dioxide then merges with the final treated wastewater, generating carbon dioxide bubbles in the final treated wastewater. The final treated wastewater containing carbon dioxide bubbles is then discharged through the treated water discharge unit 412.

[0058] The treated water transfer pump 42 is configured to be connected to the bubble treated water generation unit 41, that is, the treated water discharge unit 412, and is configured to transfer the final treated wastewater containing carbon dioxide bubbles from the bubble treated water generation unit 41 to the bubble splitter 43, thereby generating a supply transfer flow.

[0059] The bubble splitter 43 is connected to the treated water discharge section 412 of the bubble treated water generation section 41 via the treated water transfer pump 42. The bubble splitter 43 is configured to receive final treated wastewater containing carbon dioxide bubbles from the bubble treated water generation section 41, and to break up the carbon dioxide bubbles to form carbon dioxide nanobubbles.

[0060] The bubble splitter 43 is configured to include a splitter chamber section 431, an inlet pipe section 432, a bubble crushing cup section 433, and an outlet pipe section 434.

[0061] The splitter chamber section 431 is configured to provide a bubble-breaking space into which final treated wastewater containing carbon dioxide bubbles flows, and into which carbon dioxide bubbles contained in the final treated wastewater are broken up.

[0062] The inlet pipeline section 432 is connected to the treated water transfer pump 42 and is positioned vertically downward to the splitter chamber section 431. It is configured to allow the final treated wastewater containing carbon dioxide bubbles, transferred from the treated water transfer pump 42, to flow into the splitter chamber section 431, forming a downward-moving water flow.

[0063] The bubble-breaking cup section 433 is cylindrical with an open top and is installed inside the splitter chamber section 431 so as to surround the inlet pipe section 432. It is configured so that the final treated wastewater discharged downwards through the inlet pipe section 432 collides with it, causing temporary breakup of carbon dioxide bubbles.

[0064] The outflow pipeline section 434 is connected to the nozzle section 45 and is arranged in parallel with the bubble-breaking cup section 433 inside the splitter chamber section 431, facing upwards. The final treated water discharged upwards from the bubble-breaking cup section 433 flows into the outflow pipeline section 434, moves to the lower part of the splitter chamber section 431, and then flows into the outflow pipeline section 434 before being discharged to the nozzle section 45.

[0065] The nozzle section 45 is connected to the outlet pipe section 434 of the bubble splitter 43 and installed inside the algae cultivation apparatus 20, and is configured to discharge and supply the final treated wastewater containing carbon dioxide nanobubbles into the algae cultivation apparatus 20.

[0066] On the other hand, referring to Figure 4, the bubble splitter 43 in the present invention may further include a flow path extension 435 provided inside the splitter chamber 431 between the bubble-breaking cup 433 and the outflow pipe 434, which performs secondary bubble breaking as the final treated water discharged upward from the bubble-breaking cup 433 forms a zigzag flow path.

[0067] The flow path extension 435 can be configured to include a first flow path extension partition wall 435a that extends vertically downward from the ceiling of the splitter chamber 431, and a second flow path extension partition wall 435b that is formed alongside the first flow path extension partition wall 435a and extends vertically upward from the bottom of the splitter chamber 431.

[0068] Such a flow path extension 435 may consist of one, as shown in Figure 4(a), two, as shown in Figure 4(b), or three, as shown in Figure 4(c).

[0069] The size of the carbon dioxide nanobubbles contained in the final treated wastewater can be adjusted according to the number of such flow path extensions 435 installed.

[0070] The more flow path extensions 435 are installed, the smaller the size of the carbon dioxide nanobubbles contained in the final treated wastewater can be.

[0071] The nanobubble apparatus 40 of the present invention is composed of one channel extension 435, and has a range of 950 to 1050 nanometers (nm, 10 -9 It is possible to generate final wastewater containing m-sized carbon dioxide nanobubbles and supply it to the algae cultivation device 20.

[0072] Furthermore, the nanobubble device 40 of the present invention is composed of two flow path extensions 435, and can generate final wastewater treatment water containing carbon dioxide nanobubbles of 800 to 900 nanometers in size and supply it to the algae cultivation device 20.

[0073] Furthermore, the nanobubble device 40 of the present invention is composed of three flow path extensions 435, and can generate final wastewater treatment water containing carbon dioxide nanobubbles of 650 to 750 nanometers in size and supply it to the algae cultivation device 20.

[0074] However, in the present invention, if the nanobubble device 40 is configured with four or more flow path extensions 435, it is possible to generate even finer nanometer-sized carbon dioxide nanobubbles and supply the final treated wastewater to the algae cultivation device 20. However, in this case, the length of the nanobubble device 40 from left to right becomes longer, which may limit the installation area. Therefore, it is preferable to configure it with up to three units.

[0075] In this way, nanometer-sized carbon dioxide nanobubbles are introduced into the final treated wastewater via the nanobubble device 40, and then supplied to the algae cultivation device 20 via the nozzle section 45, where algae containing lipids that serve as raw materials for biodiesel can be produced.

[0076] The carbon dioxide, which is nanobubbled in the final wastewater treatment water supplied to the algae cultivation device 20 via the nanobubble device 40, is consumed during algae growth and can be removed by more than 99% in the algae cultivation device 20. The N and P remaining in the final wastewater treatment water are also consumed during algae growth and can be removed by more than 99% in the algae cultivation device 20.

[0077] In other words, the present invention dissolves carbon dioxide nanobubbles in the final wastewater treatment water using the nanobubble device 40 and introduces them into the algae cultivation device 20. This makes it possible to drastically reduce the floating velocity of the carbon dioxide nanobubbles in the algae cultivation device 20 compared to micrometer-sized nanobubbles, greatly increasing the residence time of the carbon dioxide nanobubbles in the final wastewater treatment water. As a result, the supply cycle of the final wastewater treatment water supplied to the algae cultivation device 20 can be lengthened, eliminating the need to recover the floating carbon dioxide and allowing it to be completely consumed in algae cultivation.

[0078] On the other hand, referring to Figure 5, the nanobubble apparatus (nanobubble generator) 40 of the present invention is configured to further include an ultrasonic vibration unit 436 and bubble-breaking disc units 437, 478 in the bubble splitter 43.

[0079] The ultrasonic vibrating section 436 is positioned to contact the lower surface of the bubble-breaking cup section 433. By vibrating the bubble-breaking cup section 433, the final treated wastewater discharged downwards through the inlet pipe section 432 collides with the bottom of the bubble-breaking cup section 433, causing temporary crushing of carbon dioxide bubbles. This allows for the crushing of bubbles into finer particles.

[0080] The bubble-breaking disc sections 437 and 438 include a first bubble-breaking disc 437 and a second bubble-breaking disc 438. The first bubble-breaking disc 437 is fixed to the outer circumferential surface of the inlet pipe section 432, and the second bubble-breaking disc 438 is fixed to the inner circumferential surface of the bubble-breaking cup section 433. The first bubble-breaking disc 437 and the second bubble-breaking disc 438 are configured to face each other at the same height.

[0081] Furthermore, the outer end of the first bubble-breaking disc 437 is provided with a first tip portion 437a that gradually thins in thickness and becomes pointed, and the inner end of the second bubble-breaking disc 438 is provided with a second tip portion 438a that gradually thins in thickness and becomes pointed. The first tip portion 437a and the second tip portion 438a are positioned at the same height, facing each other and spaced apart by several millimeters to several nanometers.

[0082] The bubble-breaking discs 437 and 438 having such a configuration can be configured to further break down fine bubbles in the final treated wastewater that is transported upward through the gap between the first bubble-breaking disc 437 and the second bubble-breaking disc 438, while the second bubble-breaking disc 438 also vibrates in conjunction with the vibration of the ultrasonic vibration unit 436.

[0083] Hereinafter, with reference to Figures 6 and 7, a carbon dioxide reduction and utilization system in a wastewater treatment plant according to the second embodiment of the present invention will be described.

[0084] The carbon dioxide reduction and utilization system in the wastewater treatment plant of the second embodiment differs from the first embodiment in that it further includes a culture information monitoring device 50. Otherwise, it is identical to the first embodiment. Therefore, the same drawing numbers are used for identical components, and their descriptions are omitted. Instead, the differing components, namely the culture information monitoring device 50, will be described in detail.

[0085] The culture information monitoring device 50 is configured to calculate and monitor culture information, which indicates the growth of microalgae and the carbon dioxide fixation efficiency under the environmental conditions of the algae culture device, through mathematical modeling.

[0086] The culture information monitoring device 50 is configured to include an operating condition input module 51, a data storage module 52, a microalgae CCU model drive module 55, and a result report generation module 56.

[0087] The culture information monitoring device 50 is configured as a server, a computing device, and each module of the culture information monitoring device 50 can be configured as software, hardware, or an integrated software and hardware configuration.

[0088] The operating condition input module 51 is configured to receive and set operating condition information for the algae culture apparatus 20, including the shape, volume, pH, light intensity, water temperature, pH of the inflow, nitrogen and phosphorus concentrations, carbon dioxide concentration and inflow rate, carbon dioxide solubility and transfer rate due to nanobubble operation, microalgae species information, initial inflow of microalgae, new inflow of microalgae, initial concentration of microalgae, and biomass generation due to algae growth. This operating condition information may be input by various sensors provided in the algae culture apparatus 20, or it may be configured to be directly input by an administrator via a user interface provided.

[0089] The data storage module 52 is configured to store operating conditions input via the operating condition input module 51, and result data obtained by driving the microalgae CCU model drive module 55. Here, the result data obtained by driving the microalgae CCU model drive module 55 may include the growth rate of microalgae, carbon dioxide fixation efficiency, and the increase in microalgae biomass, and may include an operating condition DB 53 in which operating conditions are stored and managed, and a modeling result DB 54 in which result data is stored and managed.

[0090] The microalgae CCU model drive module 55 is configured to calculate the growth rate of microalgae, the carbon dioxide fixation efficiency, and the increase in microalgae biomass based on the operating condition information input from the operating condition input module 51, and to store and manage the calculated result data in the data storage module 52.

[0091] The microalgae CCU model drive module 55 calculates the microalgae growth rate per unit time (Specific Growth Rate, unit: day) using formula (1). -1 It is configured to calculate ).

[0092] The calculation formula (1) is as follows:

[0093]

number

[0094] Here, μ (Specific Growth Rate, unit: day) -1 ) is the calculated growth rate of microalgae per unit time, μ max This is the maximum growth rate that microalgae can reach in a specific environment. JPEG2026116775000003.jpg1620 is the substrate concentration effect value. JPEG2026116775000004.jpg1718 shows the light intensity effect value.

[0095] Furthermore, in the substrate concentration effect, S is the substrate concentration required for the growth of microalgae, and K S is the substrate concentration when the substrate concentration of microalgae reaches half of μ max .

[0096] Also, in the light intensity effect, I is the intensity of light for photosynthesis, and K I is the light intensity when the light intensity reaches half of μ max .

[0097] In the substrate effect, if the substrate concentration is low, the growth rate of algae also decreases. When S >> K S , the growth rate of algae approaches μ max , and when S << K S , it converges to almost 0.

[0098] Also, in the light intensity effect, if the light is strong, the rate increases, but if it exceeds a certain level, it becomes saturated and the growth rate does not increase any further. When I >> K S , the growth rate of algae approaches μ max , and when I << K S , the growth rate converges to almost 0.

[0099] The microalgae CCU model driving module 55 is configured to calculate the carbon dioxide fixation efficiency according to the calculation formula (2).

[0100] The calculation formula (2) is as follows.

[0101] [Number]

[0102] Here, E CO2 (CO2 Fixation Efficiency, unit: %) is the ratio of the actually fixed carbon dioxide to the input carbon dioxide, and P CO2,input (Input CO2, unit: g or mol) is the amount of carbon dioxide input into the algae cultivation device 20, and P CO2,fixed(Units: g or mol) indicates the amount of carbon dioxide fixed during photosynthesis and biological growth processes in microalgae.

[0103] The microalgae CCU model drive module 55 is configured to calculate the increase in microalgae biomass using calculation formula (3).

[0104] The calculation formula (3) is as follows:

[0105]

number

[0106] Thus, the microalgae CCU model drive module 55 can calculate result data such as the growth rate of microalgae per unit time, carbon dioxide fixation efficiency, and increase in microalgae biomass based on input conditions using mathematical modeling including calculation formulas (1), (2), and (3). Furthermore, based on the result data thus calculated, it can optimize the operation of the algae cultivation device 20 by feeding back the input condition information to improve the growth rate of microalgae, carbon dioxide fixation efficiency, and increase in microalgae biomass.

[0107] The results report generation module 56 can be configured to generate and save results data, including the growth rate of microalgae per hour, carbon dioxide fixation efficiency, and increase in microalgae biomass, calculated by the microalgae CCU model driving module 55, in a graph-format file, and to output the generated graph-format results data on the screen.

[0108] Although the present invention has been illustrated and described above in relation to preferred embodiments illustrating the principles of the present invention, the present invention is not limited to the configuration and operation as illustrated and described herein. Rather, those skilled in the art will understand that there are many possible changes and modifications to the present invention without departing from the spirit and scope of the appended claims. Accordingly, all such appropriate changes and modifications and equivalents should be considered to fall within the scope of the present invention. [Explanation of Symbols]

[0109] 10. Sewage treatment equipment 11 Sedimentation basin 12 Primary sedimentation pond 13. Biological Reactor 14 Final settling tank 15. Total Phosphorus Treatment Facilities 16 Disinfection equipment 20 Algae cultivation equipment 30 Gas collection device 40 nanobubble device 41. Bubble-treated water generation unit 411 Treated water inlet 412 Treated water discharge section 413 Gas inlet 42. Treated water transfer pump 43 Bubble Splitter 431 Splitter Chamber Section 432 Inflow pipe section 433 Bubble-breaking cup section 434 Outflow pipe section 45 Nozzle section 50 Culture Information Monitoring Device 51 Operating Condition Input Module 52 Data storage modules 53 Operating conditions DB 54 Modeling Results Database 55 Microalgae CCU Model Drive Module 56. Result Report Generation Module

Claims

1. An algae cultivation apparatus that produces microalgae by cultivating them using carbon dioxide generated in a sewage treatment device and treated sewage water, A gas collection device for collecting carbon dioxide generated in the aforementioned sewage treatment device, A nanobubble device is supplied with treated wastewater treated in the wastewater treatment device and carbon dioxide collected from the gas collection device, and the treated wastewater in which the carbon dioxide has been dissolved in nanobubbles is supplied to the algae cultivation device. A system for reducing and utilizing carbon dioxide in a sewage treatment plant, characterized by including [a specific element].

2. The gas collection device is configured to collect carbon dioxide generated in the primary sedimentation tank and biological reaction tank of the wastewater treatment device and supply it to the nanobubble device, characterized in that it is a system for reducing and utilizing carbon dioxide in a wastewater treatment plant according to claim 1.

3. The nanobubble apparatus is A bubble-treated water generation unit is comprised of an ejector, which is supplied with the treated wastewater and transported and discharged at high speed, and the negative pressure generated by the flow of the transported treated wastewater draws carbon dioxide from the gas collection device, which then merges with the treated wastewater and is discharged; A treated water transfer pump connected to the bubble treated water generation unit generates a flow of the treated wastewater, A bubble splitter is connected to the bubble treated water generation unit via the treated water transfer pump, to which treated wastewater containing carbon dioxide bubbles is supplied from the bubble treated water generation unit, and which breaks the carbon dioxide bubbles to form carbon dioxide nanobubbles. A nozzle unit connected to the bubble splitter and installed in the algae cultivation apparatus for discharging treated wastewater containing carbon dioxide nanobubbles into the algae cultivation apparatus, A system for reducing and utilizing carbon dioxide in a sewage treatment plant according to claim 2, characterized by including the following.

4. The aforementioned bubble splitter is The splitter chamber section provides a bubble-breaking space into which the treated wastewater flows and into which carbon dioxide bubbles contained in the treated wastewater are broken up, An inlet pipeline is connected to the treated water transfer pump, positioned vertically to the splitter chamber, and forms a water flow that transfers the treated wastewater transferred from the treated water transfer pump downward from the splitter chamber. It is configured as a cylindrical shape with an open top, and is provided within the splitter chamber so as to surround the inlet pipe section, and the bubble-breaking cup section is formed when treated wastewater discharged downward through the inlet pipe section collides with it and breaks primary bubbles, An outlet pipeline is connected to the nozzle section and is provided in parallel with the bubble-breaking cup section inside the splitter chamber section, allowing treated wastewater discharged upward from the bubble-breaking cup section to flow into and be discharged to the nozzle section. A system for reducing and utilizing carbon dioxide in a sewage treatment plant according to claim 3, characterized by including the following.

5. The carbon dioxide reduction and utilization system in a sewage treatment plant according to claim 4, further comprising a flow path extension which is provided inside the splitter chamber between the bubble-breaking cup and the outflow pipeline, and in which treated sewage water discharged upward from the bubble-breaking cup forms a zigzag flow path while performing secondary bubble breaking.

6. The system for reducing and utilizing carbon dioxide in a sewage treatment plant according to claim 5, further comprising a flow path extension, wherein at least one of the flow path extensions is arranged in parallel between the bubble-breaking cup section and the outflow pipeline section.

7. The nanobubble apparatus is The aforementioned flow path extension is configured as a single unit, generating treated wastewater containing carbon dioxide nanobubbles of 950 to 1050 nanometer size and supplying it to the algae cultivation apparatus, The aforementioned flow channel extension is composed of two sections, and wastewater containing carbon dioxide nanobubbles of size 800 to 900 nanometers is generated and supplied to the algae cultivation apparatus, or, The wastewater treatment plant carbon dioxide reduction and utilization system according to claim 6, characterized in that the flow path extension section is composed of three sections and is configured to generate treated wastewater containing carbon dioxide nanobubbles of 650 to 750 nanometer size and supply it to the algae cultivation device.

8. The carbon dioxide reduction and utilization system in a sewage treatment plant according to claim 1, further comprising a culture information monitoring device that calculates and monitors result data including the growth rate of microalgae, carbon dioxide fixation efficiency, and increase in microalgae biomass based on the environmental conditions of the algae culture apparatus, through mathematical modeling.

Images