Carbon sequestration system for synergistically purifying industrial aquaculture tail water based on fish-algae symbiosis

Abstract

The invention discloses a carbon sequestration system for synergistically purifying industrial aquaculture tail water based on fish-algae symbiosis, which comprises a filter cloth filter tank, an ozone catalytic oxidation system, a microalgae photobioreactor, an algae-water separation device and a filter material filter tank, water quality pretreatment is carried out through an ozone catalytic oxidation system, most of ammonia nitrogen and nitrite nitrogen in water are oxidized into nitrate nitrogen, then the nitrate nitrogen enters a microalgae photobioreactor, algae liquid obtained after reaction passes through an algae-water separation device, filtrate and filter residues are obtained, the filtrate is disinfected and filtered and then returns to the factory-like culture pond, and the water quality is purified. The method comprises the following steps of: recycling the raw materials of the microalgae photobioreactor to achieve the purpose of circulation, drying the filter residue in a factory to prepare a high-protein feed raw material to achieve the purpose of resource reutilization, and meanwhile, purifying and pretreating the tail gas reaching the standard in the factory, and introducing the tail gas rich in carbon dioxide into the microalgae photobioreactor to achieve the purpose of biological carbon sequestration.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tail water treatment of industrial aquaculture, and in particular to a carbon fixation system based on fish-algae symbiosis for treating tail water of industrial aquaculture. BACKGROUND

[0002] Although industrial aquaculture can improve production, the tail water problem cannot be ignored. The tail water contains a large amount of pollutants such as ammonia nitrogen and nitrite nitrogen, which mainly come from the excrement of aquatic animals and the decomposition of residual feed that is not completely ingested, and not only poses a threat to the ecological environment, but also affects subsequent aquaculture activities. Traditional treatment methods such as biological methods are environmentally friendly, but have the defects of low efficiency and being restricted by environmental factors; while chemical methods have high efficiency, but require a large amount of chemicals, have high cost and produce a large amount of waste.

[0003] At the same time, microalgae cultivation technology provides a new way for wastewater treatment. The nitrogen, phosphorus and other nutrients contained in the wastewater provide nutrients for the growth of microalgae. Microalgae are small in size, strong in survival ability, fast in reproduction and easy to cultivate, and have been widely used in the field of wastewater treatment. In the process of aquaculture, leftover feed, feces and drug residues can lead to water eutrophication, while microalgae can directly use light as energy and CO2 in air or flue gas as carbon source to carry out photosynthesis with nitrogen, phosphorus and other nutrients in water to synthesize organic biomass needed for their growth, thereby effectively removing nitrogen, phosphorus and chemical oxygen demand (COD) in water to achieve the purpose of purifying wastewater. At the same time, microalgae biomass is rich in high-protein and unsaturated fatty acids, which can be processed into high-value-added products such as feed and nutritional health products, generating economic value. The factory flue gas generated during the processing process can be directly introduced into the photobioreactor to supplement the inorganic carbon source for the growth of microalgae, which not only realizes resource recycling and economic value, but also achieves the purpose of carbon reduction and pollution reduction and green production.

[0004] Therefore, in order to combine efficient treatment of industrial aquaculture tail water, microalgae cultivation biomass conversion and green production carbon reduction and pollution reduction, it is of great significance to develop a carbon fixation system based on fish-algae symbiosis for treating tail water of industrial aquaculture. SUMMARY

[0005] The present application aims to provide a carbon fixation system based on fish-algae symbiosis for treating tail water of industrial aquaculture, which can efficiently remove pollutants such as ammonia nitrogen and nitrite nitrogen, phosphorus and other pollutants generated during the aquaculture process.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] The application discloses a carbon fixation system for aquaculture tail water, which comprises a filter cloth filter, an ozone catalytic oxidation system, a microalgae photobioreactor, an algae-water separation device and a filter material filter.

[0008] In a possible implementation, the filter cloth filter is used to filter large-particle impurities and suspended solids in water, and a fiber filter cloth is used as the filter medium, and the filter material precision ranges from 5 to 20 microns.

[0009] In a possible implementation, the water quality of tail water entering the microalgae photobioreactor is required to be 0-1 mg / L in nitrite content and 0-10 mg / L in ammonia nitrogen content, and if the water quality exceeds the concentration standard, pretreatment is required, wherein the ozone catalytic oxidation system is used for the pretreatment, and a biological charcoal-based catalyst, an iron-based catalyst and a magnesium-based catalyst are selected as the catalyst in the ozone catalytic oxidation system. The ozone concentration is controlled to be 5-15 mg / L, and the hydraulic retention time is 10-60 min.

[0010] In a possible implementation, the light intensity in the microalgae photobioreactor is required to be 4000-10000 lx, the light source is natural light, and the temperature needs to be maintained at room temperature.

[0011] In a possible implementation, the microalgae needs to be selected from high-protein and nutrient-rich algae species, and the high-protein and nutrient-rich algae species include any one of chlorella, spirulina, dunaliella salina and nannochloropsis; in the microalgae photobioreactor, the initial inoculation ratio of the microalgae is controlled to be 10%-30%, and the residence time of the tail water is controlled to be 3-7 days.

[0012] In a possible implementation, the carbon dioxide source of the microalgae photobioreactor is flue gas discharged by a factory, wherein particulate matters in the flue gas need to be pretreated, and when the carbon dioxide content in the microalgae photobioreactor is insufficient, a carbon dioxide generator is used for aeration, and the aeration time is 8-16 h / d.

[0013] In a possible implementation, the aquaculture tail water backflow must be subjected to disinfection treatment, wherein the disinfection treatment adopts any one of ozone disinfection method and ultraviolet disinfection method, in the disinfection treatment, the time of ozone disinfection is controlled to be 5-30 min, and before the tail water enters the min aquaculture pond, the ozone concentration needs to be lower than 0.005 mg / L.

[0014] In a possible implementation, the algal residue separation device is equipped with a plate-and-frame filter press, a centrifugal separator and a belt filter, after the algal residue subjected to solid-liquid separation treatment, low-temperature drying or freeze-drying treatment is performed, and then the algal residue is sold as a high-protein feed raw material or directly used as an aquaculture feed.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] ① The carbon fixation system based on fish-algae symbiotic and synergistic purification of factory aquaculture tail water provided by the present application firstly removes large-particle impurities through a filter cloth filter tank, and then utilizes an ozone catalytic oxidation system to convert high-concentration ammonia nitrogen and nitrite nitrogen in the factory aquaculture tail water into nitrate nitrogen which is beneficial to the growth of microalgae. This process not only promotes the large accumulation of microalgae biomass, but also accelerates the purification process of the tail water. The treated water is backflowed after disinfection and filtration, and the whole circulation system does not add new chemicals and does not produce new pollutants.

[0017] ② The algal sludge separated by the system is rich in protein and polyunsaturated fatty acids, which meets the nutrition required by fish growth. After drying, the algal sludge is ground into algal powder, which can be processed into high-nutrition health products, fish feed and other high-value-added products, thereby generating economic value. The fish feed can also be used for fish feeding, realizing the recycling and reuse of resources.

[0018] ③ Microalgae in the system fix CO2 in the air as an inorganic carbon source, effectively promoting "carbon reduction and pollution reduction". Factory flue gas generated in the process of processing fish feed and nutrition health products can be introduced into a microalgae photobioreactor as a supplementary carbon source for the rapid growth of microalgae, and accelerate the process of purifying industrial aquaculture tail water, further realize the "negative carbon" goal, and recycle the nitrogen and phosphorus in the aquaculture tail water. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0020] Figure 1A flowchart of a carbon fixation system based on fish-algal symbiotic purification of tail water of industrial aquaculture in the embodiment of the present application;

[0021] Figure 2 A structural diagram of a carbon fixation system based on fish-algal symbiotic purification of tail water of industrial aquaculture in the embodiment of the present application;

[0022] Figure 3 Another form of a microalgae photoreactor in a carbon fixation system based on fish-algal symbiotic purification of tail water of industrial aquaculture in the embodiment of the present application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0024] Embodiment:

[0025] It should be noted that the terms “comprising” and “having” and any variations of them in the embodiments of the present application are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units that are not clearly listed or inherent to the process, method, product or device.

[0026] Figure 1 A flowchart of a carbon fixation system based on fish-algal symbiotic purification of tail water of industrial aquaculture in the embodiment of the present application; Figure 2 A structural diagram of a carbon fixation system based on fish-algal symbiotic purification of tail water of industrial aquaculture in the embodiment of the present application; see Figures 1 to 2The embodiment of the present application provides a carbon fixation system for aquaculture tail water, which comprises a filter cloth filter, an ozone catalytic oxidation system, a microalgae photobioreactor, an algae-water separation device and a filter material filter, wherein tail water from a factory farming pond is filtered by the filter cloth filter to remove impurities, and then is subjected to water quality pretreatment by the ozone catalytic oxidation system to oxidize most of ammonia nitrogen and nitrite nitrogen in the water into nitrate nitrogen, and then enters the microalgae photobioreactor, and the obtained algae liquid after reaction is subjected to the algae-water separation device to obtain filtrate and filter residue, the filtrate is returned to the factory farming pond after sterilization and filtration, so that the purpose of recycling is achieved, and the filter residue is dried in a factory to be made into high-protein feed raw materials, so that the purpose of resource recycling is achieved, and meanwhile, the tail gas of the factory after reaching the standard is subjected to purification pretreatment, and the tail gas rich in carbon dioxide is introduced into the microalgae photobioreactor, so that the purpose of biological carbon fixation is achieved.

[0027] In an embodiment, the filter cloth filter is used to filter large-particle impurities and suspended solids in water, and the filter medium adopts fiber filter cloth, and the filter precision ranges from 5 to 20 microns.

[0028] In an embodiment, the water quality of tail water entering the microalgae photobioreactor for cultivation requires that the nitrite content is 0-1 mg / L and the ammonia nitrogen content is 0-10 mg / L, and if the water quality exceeds the concentration standard, pretreatment needs to be performed, wherein the pretreatment adopts an ozone catalytic oxidation system, and in the ozone catalytic oxidation system, the catalyst is selected from a biological charcoal-based catalyst, an iron-based catalyst and a magnesium-based catalyst. The ozone concentration should be controlled to be 5-15 mg / L, and the hydraulic retention time is 10-60 min.

[0029] In an embodiment, in the microalgae photobioreactor, the requirement for light intensity is 4000-10000 lx, the light source is natural light, and the temperature needs to be maintained at room temperature level.

[0030] In an embodiment, the microalgae needs to select an algal species rich in high protein and nutrients, and the algal species rich in high protein and nutrients includes any one of chlorella, spirulina, dunaliella salina and nannochloropsis; in the microalgae photobioreactor, the initial inoculation ratio of the microalgae is controlled to be between 10% and 30%, and the residence time of the tail water is controlled to be 3 to 7 days.

[0031] In an embodiment, the source of carbon dioxide of the microalgae photobioreactor is flue gas discharged by a factory, wherein particulate matters in the flue gas need to be subjected to purification pretreatment, and when the carbon dioxide content in the microalgae photobioreactor is insufficient, a carbon dioxide generator is used for aeration, and the aeration time is 8 to 16 h / d.

[0032] In an embodiment, the aquaculture tail water backflow must be subjected to disinfection treatment, wherein the disinfection treatment adopts any one of ozone disinfection method and ultraviolet disinfection method, and in the disinfection treatment, the time of ozone disinfection is controlled to be 5-30 min, and before the tail water enters the min aquaculture pond, the ozone concentration needs to be lower than 0.005 mg / L.

[0033] In an embodiment, the algal residue separation device is equipped with a plate-and-frame filter press, a centrifugal separator and a belt filter, and after the solid-liquid separation treatment, the algal residue is subjected to low-temperature drying or freeze-drying treatment, and then is sold as a high-protein feed raw material or is directly used as an aquaculture feed.

[0034] In an embodiment, the microalgae photobioreactor includes any one of a column photobioreactor, a pipeline photobioreactor, a flat plate and an open runway pond.

[0035] In an embodiment, in the microalgae photobioreactor, an aeration device is connected with an aeration head through an air compressor to provide CO2 for the closed reactor, wherein the aeration device has various forms, such as any one of an aeration stone and an aeration ring, as shown in the figure; and the source of CO2 is also extensive, covering any one of a CO2 generator and factory flue gas. Figure 3

[0036] The working principle of the present application is introduced as follows:

[0037] The factory aquaculture tail water carbon fixation system based on fish-algae symbiotic and synergistic purification technology provided by the present application is mainly used for treating wastewater generated by a small fish pond in an embodiment. In the direction of water flow, the specific operation steps are as follows:

[0038] Firstly, the tail water discharged from the factory aquaculture pond is filtered through a filter cloth filter to remove large-particle pollutants; and then enters an ozone catalytic oxidation system. Unlike other treatment methods, the tail water is preliminarily introduced into the system, which can preliminarily reduce high-concentration ammonia nitrogen and nitrite nitrogen caused by intensive aquaculture and low water exchange frequency, and convert them into non-toxic nitrate nitrogen through nitrification, so as to avoid the inhibitory effect of high-concentration ammonia nitrogen and nitrite nitrogen on the accumulation of microalgae biomass. After the pretreatment of the system, the removal effect of pollutants such as ammonia nitrogen in water is further improved.

[0039] In an embodiment, the photobioreactor is preferably a column photobioreactor, which is equipped with an aeration device to provide inorganic carbon sources for microalgae, and at the same time, the aquaculture tail water is used as a microalgae culture medium to provide growth factors. The ozone system pretreatment of the present application not only promotes the rapid accumulation of biomass, but also more effectively removes nitrogen, phosphorus and other pollutants in water.

[0040] ​Then, the tail water is separated by an algae water separation device, and the separation method includes but is not limited to centrifugation, plate and frame filter press, rapid microporous filtration, magnetic separation and the like. The separated filtrate is sterilized and filtered, and then returned to the breeding pond to complete the circulation. The separated algae mud is dried and ground into algae powder, which is processed into health products, biodiesel, fish feed and other high value-added products in a feed processing plant. The fish feed can be put back into the breeding pond.

[0041] In addition, the factory flue gas discharged by the processing plant contains a large amount of CO2 gas, and the microalgae domesticated by high-concentration CO2 can adapt to the factory flue gas as an inorganic carbon source. Therefore, in the process of treating the tail water of the factory breeding, the factory flue gas is introduced into the domesticated microalgae culture photoreactor to provide the microalgae growth nutrient source together with the breeding tail water, which not only reduces the factory flue gas emission and promotes carbon emission reduction, but also achieves the "negative carbon" goal.

[0042] The beneficial effects of the present application are described below in combination with data:

[0043] Example 1

[0044] In this embodiment, a carbon fixation system based on fish-algae symbiotic and synergistic purification technology is used to treat the tail water of a factory aquaculture pond in Guangdong Province. The ammonia nitrogen content in the water body is 15 mg / L, the nitrite nitrogen content is 2.1 mg / L, and the nitrate nitrogen content is 2.8 mg / L. The algae used in the reactor is chlorella, and the specific treatment steps are as follows:

[0045] First, the tail water enters the filter cloth filter tank and stays for 30 minutes to remove feces and feed residues and other large particle pollutants in the tail water, and then the filter residue is discharged, and the filtrate enters the ozone catalytic oxidation device.

[0046] In the ozone catalytic oxidation device, the ozone concentration is maintained at 8 mg / L, and the ozone gas is aerated from the bottom of the device upward, uniformly diffused, and promoted to fully react the catalyst with the tail water, with a residence time of 30 minutes.

[0047] Then, the effluent from the ozone catalytic oxidation device enters the column photobioreactor and stays for 6 days. During this period, the air compressor compresses air through the intermittent aeration of aeration stone, which works for 5 minutes and stops for 5 minutes to disperse air in water; the LED light source is turned on at a fixed time every day, and the light-dark time ratio is 12 hours:12 hours; the heating rod maintains the water temperature at 25℃.

[0048] Finally, the reactor effluent is separated by an algae water separation device, and the algae residue is separated, and the separated liquid enters the filter material filter tank and is filtered after ozone sterilization to discharge the final effluent.

[0049] Example 2

[0050] This embodiment uses a fish-algae symbiotic system to purify the tail water of industrial aquaculture. The ammonia nitrogen content of the water is 15 mg / L, the nitrite nitrogen content is 2.1 mg / L, and the nitrate nitrogen content is 2.8 mg / L. The algal species used in the reactor is Chlorella vulgaris. The treatment steps are as follows:

[0051] First, the tail water enters the filter cloth filter, and stays for 30 minutes to remove large particle pollutants such as feces and feed residues in the tail water. After the filter residue is discharged, the filtrate directly enters the microalgae photobioreactor.

[0052] Next, the filtrate stays in the photobioreactor for 6 days. During this period, the air compressor intermittently aerates the reactor through aeration stones, working for 5 minutes and stopping for 5 minutes to disperse air in the water. The LED light source is turned on at a fixed time every day, with a light-dark ratio of 12 hours:12 hours; the heating rod maintains the water temperature at 25°C.

[0053] Finally, the reactor effluent is separated from the algal residue by an algae-water separation device, and the separated liquid enters the filter material filter, which is filtered after ozone disinfection and discharged.

[0054] Example 3:

[0055] This embodiment uses a fish-algae symbiotic system to purify the tail water of industrial aquaculture. The ammonia nitrogen content of the water is 15 mg / L, the nitrite nitrogen content is 2.1 mg / L, and the nitrate nitrogen content is 2.8 mg / L. The algal species used in the reactor is Chlorella vulgaris. The treatment steps are as follows:

[0056] First, the tail water enters the filter cloth filter, and stays for 30 minutes to remove large particle pollutants such as feces and feed residues in the tail water. After the filter residue is discharged, the filtrate enters the ozone catalytic oxidation device.

[0057] In the ozone catalytic oxidation device, the ozone concentration is maintained at 4 mg / L. Ozone gas is aerated from the bottom of the device upwards, uniformly diffused, and promotes the reaction of the catalyst with the tail water, with a residence time of 30 minutes.

[0058] Subsequently, the effluent from the ozone catalytic oxidation device enters the six-column photobioreactor, and stays for 6 days. The air compressor intermittently aerates the reactor through aeration stones, working for 5 minutes and stopping for 5 minutes to disperse air in the water. The LED light source is turned on at a fixed time every day, with a light-dark ratio of 12 hours:12 hours; the heating rod maintains the water temperature at 25°C.

[0059] Finally, the reactor effluent is separated from the algal residue by an algae-water separation device, and the separated liquid enters the filter material filter, which is filtered after ozone disinfection and discharged.

[0060] Example 4:

[0061] This example uses a fish-algae symbiotic system to purify the tail water of a factory aquaculture pond in Guangdong Province. The ammonia nitrogen content in the water body is 15 mg / L, the nitrite nitrogen content is 2.1 mg / L, and the nitrate nitrogen content is 2.8 mg / L. The algal species used in the reactor is Chlorella vulgaris, and the treatment steps are as follows:

[0062] First, the tail water enters the filter cloth filter, and stays for 30 minutes to remove feces and feed residues and other large particle pollutants in the tail water. After the filter residue is discharged, the filtrate enters the ozone catalytic oxidation device.

[0063] In the ozone catalytic oxidation device, the ozone concentration is 8 mg / L. Ozone gas is aerated from the bottom of the device upwards, uniformly diffused, and promotes the full reaction of the catalyst with the tail water, with a residence time of 30 minutes.

[0064] Subsequently, the effluent from the ozone catalytic oxidation device enters the six-column photobioreactor, and stays for 7 days. The air compressor compresses air through the aeration stone in the reactor for intermittent aeration, which is stopped for 30 minutes after working for 5 minutes to disperse air in the water. The LED light source is turned on at a fixed time every day, with a light-dark time ratio of 12 hours:12 hours. The heating rod maintains the water temperature at 25°C.

[0065] Finally, the reactor effluent is separated from the algal residue by the algal water separation device, and the separated liquid enters the filter material filter, which is discharged after ozone disinfection.

[0066] Example 5:

[0067] This example uses a fish-algae symbiotic system to purify the tail water of a factory aquaculture pond in Guangdong Province. The ammonia nitrogen content in the water body is 15 mg / L, the nitrite nitrogen content is 2.1 mg / L, and the nitrate nitrogen content is 2.8 mg / L. The algal species used in the reactor is Chlorella vulgaris, and the treatment steps are as follows:

[0068] First, the tail water enters the filter cloth filter, and stays for 30 minutes to remove feces and feed residues and other large particle pollutants in the tail water. After the filter residue is discharged, the filtrate enters the ozone catalytic oxidation device.

[0069] In the ozone catalytic oxidation device, the ozone concentration is 8 mg / L, and the ozone gas is aerated from the bottom upwards, uniformly diffused, and promotes the full reaction of the catalyst with the tail water, with a residence time of 30 minutes.

[0070] After treatment by the ozone catalytic oxidation device, the ammonia nitrogen and nitrite nitrogen in the water are basically converted into nitrate nitrogen, which then enters the six-column photobioreactor and stays for three days. The air compressor compresses air to intermittently aerate the reactor through aeration stones, working for 5 minutes and stopping for 5 minutes to disperse the air in the water. The LED light source is turned on at a fixed time every day, with a light-dark time ratio of 12 hours: 12 hours; the heating rod maintains the water temperature at 25°C.

[0071] Finally, the reactor effluent is separated from the algae sludge by the algae-water separation device, and the separated liquid enters the filter material filter tank and is filtered after ozone disinfection and then discharged.

[0072] Table 1 shows the comparison of water quality treatment effects of the factory aquaculture tail water in the examples. By comparing the examples, it can be seen that the present application can significantly improve the treatment effect by taking measures such as ozone catalytic oxidation pretreatment, stable aeration and extension of the residence time of the aquaculture tail water. Specifically, the removal rate of ammonia nitrogen in the tail water reaches 90.5%, the removal rate of nitrite nitrogen reaches 98.1%, and the removal rate of nitrate nitrogen reaches 87.1%. The treatment method has high efficiency and remarkable effect, and the effluent water quality meets the requirements of Guangdong Provincial “Aquaculture Tail Water Discharge Standard” (DB44 / 2462-2024), and can be directly reused as aquaculture water.

[0073] Table 1 Water quality treatment effect of factory aquaculture tail water in the examples

[0074]

[0075]

[0076] In summary, the ammonia nitrogen content in the factory aquaculture tail water varies significantly due to factors such as breeding density, water change frequency and breeding species, and can exceed 50 mg / L. Ammonia nitrogen has certain toxicity and can inhibit the growth of microalgae when the concentration exceeds a certain value. According to the requirements of the present embodiment, the aquaculture tail water entering the microalgae photobioreactor needs to meet the requirements of nitrite content of 0-1 mg / L and ammonia nitrogen content of 0-10 mg / L.

[0077] In order to efficiently purify the aquaculture tail water and promote the rapid growth and biomass synthesis of microalgae, when the ammonia nitrogen and nitrite concentration in the aquaculture tail water exceeds the limited value, the present application innovatively provides an ozone catalytic oxidation system for water quality pretreatment of the aquaculture tail water entering the photobioreactor. The system can convert most of the ammonia nitrogen and nitrite nitrogen into harmless nitrate nitrogen. Nitrate nitrogen, as a high-quality nitrogen source, is usually used as a nitrogen source component in standard culture medium, and is more conducive to promoting the rapid growth and biomass synthesis of microalgae than ammonia nitrogen and nitrite nitrogen.

[0078] The water separated by the algal water separation device can reach the aquaculture tail water discharge standard or the recycling standard, and can be directly recycled as the aquaculture water body after disinfection and filtration. At the same time, the microalgae rich in protein separated can be further processed into high-value-added products such as aquaculture feed and nutritional health care products, so as to realize the recycling of the fish-algal symbiotic efficient purification of the factory tail water of the aquaculture and the biomass of the microalgae.

[0079] In addition, the factory flue gas generated in the process of processing feed contains high concentration of CO2, and the domesticated microalgae can tolerate high concentration of CO2. Therefore, the factory flue gas can be introduced into the photobioreactor to supplement the inorganic carbon source and promote the growth of the microalgae, which can not only accelerate the accumulation of the biomass of the microalgae, but also promote carbon emission reduction.

[0080] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0081] The above embodiments are only for the purpose of illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the essence of the present application should be covered within the protection scope of the present application.

Claims

1. A carbon sequestration system for aquaculture effluent, characterized by, The application relates to a filter cloth filter, an ozone catalytic oxidation system, a microalgae photobioreactor, an algae-water separation device and a filter material filter, wherein tail water from a factory breeding pool is filtered through the filter cloth filter, pre-treated through the ozone catalytic oxidation system, and then enters the microalgae photobioreactor, the tail water is filtered and separated through the algae-water separation device, the filtered water is sterilized and filtered and then returned to the factory breeding pool, the filtered residue is dried in the factory and then made into high-protein feed raw materials, the tail gas of the factory is purified and pretreated, the carbon dioxide-rich tail gas is introduced into the microalgae photobioreactor, and the purpose of biological carbon sequestration is achieved. The filter cloth filter is used for filtering large-particle impurities and suspended solids in water, the filter medium adopts fiber filter cloth, and the filter precision ranges from 5 to 20 microns.

2. A carbon sequestration system for aquaculture effluent according to claim 1, characterised in that, The water quality of the tail water entering the microalgae photobioreactor is required to be 0-1 mg / L in nitrite content and 0-10 mg / L in ammonia nitrogen content, if the water quality exceeds the concentration standard, pretreatment is needed, the ozone catalytic oxidation system is used for the pretreatment, the catalyst in the ozone catalytic oxidation system is selected from a biological charcoal-based catalyst, an iron-based catalyst and a magnesium-based catalyst, the ozone concentration is controlled to be 5-15 mg / L, and the hydraulic retention time is 10-60 min.

3. A carbon sequestration system for aquaculture effluent according to claim 1, characterised in that, In the microalgae photobioreactor, the light intensity is required to be 4000-10000 lx, the light source is natural light, and the temperature needs to be maintained at room temperature.

4. The carbon sequestration system for aquaculture effluent according to claim 1, characterized in that, The microalgae needs to select an algal species with high protein and rich nutrition, the algal species with high protein and rich nutrition includes any one of chlorella, spirulina, dunaliella salina and nannochloropsis, the initial inoculation ratio of the microalgae in the microalgae photobioreactor is controlled to be 10%-30%, and the residence time of the tail water is controlled to be 3-7 days.

5. The carbon sequestration system for aquaculture effluent according to claim 1, characterized in that, The carbon dioxide source of the microalgae photobioreactor is flue gas discharged by a factory, the particulate matters in the flue gas need to be purified and pretreated, when the carbon dioxide content in the microalgae photobioreactor is insufficient, a carbon dioxide generator is used for aeration, and the aeration time is 8-16 h / d.

6. The carbon sequestration system for aquaculture effluent according to claim 1, characterized in that, The breeding tail water reflux must be subjected to disinfection treatment, the disinfection treatment adopts any one of an ozone disinfection method and an ultraviolet disinfection method, in the disinfection treatment, the ozone disinfection time is controlled to be 5-30 min, and before the tail water enters the breeding pool, the ozone concentration needs to be lower than 0.005 mg / L.

7. The carbon sequestration system for aquaculture effluent according to claim 1, characterized in that, The algae residue separation device is provided with a plate-and-frame filter press, a centrifugal separator and a belt filter, the algae residue subjected to solid-liquid separation treatment is subjected to low-temperature drying or freeze-drying treatment, and then is sold as high-protein feed raw materials or directly used as aquatic breeding feed.

8. The carbon sequestration system for aquaculture effluent according to claim 1, characterized in that, ​

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