A coupled type recirculating aquaculture system and a recirculating aquaculture method

Abstract

This invention provides a coupled recirculating aquaculture system and method. The coupled recirculating aquaculture system includes: an aquaculture pond for aquaculture, with a central suspended solids drain pipe and a water-pushing device inside; a denitrification unit whose inlet is connected to the central suspended solids drain pipe and whose outlet is connected to the water-pushing device, the denitrification unit denitrifies the water and returns the denitrified water to the aquaculture pond via the water-pushing device; and a carbon-nitrogen ratio coordination unit connected between the water-pushing device and the denitrification unit, which adjusts the content of growth elements in the water entering the aquaculture pond according to changes in the growth elements required by the aquatic products, and simultaneously sends the water discharged from the denitrification unit into the aquaculture pond via the water-pushing device. The denitrification unit effectively removes ammonia nitrogen from the water in the aquaculture pond, ensuring the lifespan of the aquatic products and reducing the area of ​​the coupled recirculating aquaculture system.

Description

Technical Field

[0001] This invention relates to the field of agricultural aquaculture technology, and in particular to a coupled recirculating aquaculture system and a recirculating aquaculture method. Background Technology

[0002] The ecological protection and high-quality development of the Yellow River Basin was elevated to a major national strategy in 2019. Its core is to build a moderately prosperous society and revitalize urban and rural areas along the Yellow River under the constraints of water resources and the ecological environment. For the Yellow River Basin, where per capita water resources are only one-third of the national average, the main constraint is water scarcity and the resulting water environment problems. In particular, the Ningxia and Inner Mongolia irrigation areas, located in the Yellow River basin's runoff-scarce zone, receive less than 200 mm of rainfall annually, have no natural runoff, and rely on diverted water for industrial and agricultural production and domestic water use, resulting in prominent water resource problems and limited water environment capacity.

[0003] Taking 2019 as an example, agricultural water intake and consumption in the Ningxia Yellow River irrigation area and the Inner Mongolia Yellow River irrigation area both exceeded 85% of their water intake from the Yellow River, and agricultural water discharge accounted for over 92% of the total water discharge. In 2019, agricultural non-point source pollution emissions in Ningxia accounted for over 58% of the total pollutant emissions in the region. In 2019, Ningxia's total aquatic product output was 157,700 tons, with a fishery water area of ​​500,000 mu, and a planned total aquatic product output of 180,000 tons by 2025. Based on the Second National Pollution Source Census plan and Ningxia's aquatic pollution discharge coefficient, it can be calculated that the water exchange volume of aquaculture was 722 million cubic meters, accounting for 29.87% of agricultural water discharge; sediment discharge was 154,500 tons; COD emissions were 14,803.14 tons, accounting for 19.7% of agricultural non-point source COD emissions; and total nitrogen emissions were 2,364.71 tons, accounting for 31.79% of agricultural non-point source ammonia nitrogen emissions. Therefore, developing recirculating aquaculture systems is one of the effective ways to conserve water resources and reduce agricultural pollution sources in the Yellow River Basin of Northwest China.

[0004] Unlike aquaculture models in coastal, shoreline, and lakeside areas that primarily improve water quality through water exchange, inland pond aquaculture is often limited by the seasonality of agricultural irrigation water sources. During non-irrigation periods, pond water quality is poor, while during irrigation, water exchange leads to deterioration of the surrounding water system. Constrained by water resources and pond land availability, the U.S. Department of Agriculture began funding research into facility-based aquaculture in the late 20th century. The Southern Region Aquacaulture Center (SRAC) within the SRAC introduced a prototype of the Recirculating Aquaculture Tonk Production System (RAS) in 1998, based on external water treatment and recycling in aquaculture ponds. This system defined the water quality control parameters for aquaculture water bodies as dissolved oxygen, non-ionic ammonia nitrogen, nitrite nitrogen, carbon dioxide, nitrate nitrogen, pH, and alkalinity, and proposed corresponding facilities to regulate these parameters. This system was further refined in 2013. SRAC's core RAS relies on facilities outside the aquaculture ponds to ensure water quality within the ponds, while using biological filters to address the ammonia nitrogen generated daily in the aquaculture water, reducing the amount of water exchanged.

[0005] In summary, currently, domestic and international RAS (Rapid Aquaculture System) aquaculture water treatment systems are independent of the aquaculture ponds and solely undertake the function of removing ammonia nitrogen from the aquaculture water. This results in the water treatment system occupying a large area in the aquaculture workshop, which reduces the aquaculture area. At the same time, a certain amount of water exchange is still required to maintain the water quality in the aquaculture ponds. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0007] In view of this, the present invention proposes a coupled recirculating aquaculture system and a recirculating aquaculture method. The coupled recirculating aquaculture system maintains a low concentration of ammonia nitrogen in the aquaculture pond water through a denitrification unit, thus stabilizing the water quality. As part of the coupled recirculating aquaculture system, the denitrification unit eliminates the need for an additional water treatment system outside the aquaculture pond, reducing the area of ​​the coupled recirculating aquaculture system. Furthermore, a carbon-nitrogen ratio coordination unit replenishes the recirculating water with trace elements required for aquaculture, ensuring the lifespan and quality of the aquatic products.

[0008] Specifically, the following technical solutions are included:

[0009] On one hand, the present invention provides a coupled recirculating aquaculture system, the coupled recirculating aquaculture system comprising:

[0010] Aquaculture pond for aquaculture, wherein the aquaculture pond is equipped with a central suspended solids drainage pipe and a water pushing device;

[0011] The denitrification unit has its inlet connected to the central suspended solids drain pipe and its outlet connected to the water-pushing device. The denitrification unit is used to denitrify the water and then sends the denitrified water back to the aquaculture pond through the water-pushing device.

[0012] A carbon-nitrogen ratio coordination unit is connected between the water-pushing device and the denitrification unit. The carbon-nitrogen ratio coordination unit adjusts the content of growth elements in the water entering the aquaculture pond in a timely manner according to the changes in the growth elements required by the aquatic products in the aquaculture pond. At the same time, the water is sent into the aquaculture pond together with the water discharged from the denitrification unit through the water-pushing device.

[0013] Optionally, the aquaculture pond is also equipped with a central bottom drain pipe, and the recirculating aquaculture system further includes a solid-liquid separation unit connected to the central bottom drain pipe. Water passing through the solid-liquid separation unit enters the denitrification unit, and solid waste passing through the solid-liquid separation unit is discharged from the solid-liquid separation unit.

[0014] Optionally, the solid-liquid separation unit includes:

[0015] A buffer module is connected to the central bottom drain pipe and the denitrification unit. The buffer module is used to receive the sediment water in the aquaculture pond and the waste liquid in the denitrification unit.

[0016] A solid-liquid separation module, wherein the inlet of the solid-liquid separation module is connected to the buffer module, and the first outlet of the solid-liquid separation module is connected to the denitrification unit;

[0017] A solid waste treatment module, wherein the inlet of the solid waste treatment module is connected to the second outlet of the solid-liquid separation;

[0018] The waste and solid waste transportation module is connected to the outlet of the waste and solid waste harmless treatment module;

[0019] The third controller is connected to the buffer module, the solid-liquid separation module, the waste solid harmless treatment module, and the waste solid transportation module, respectively. The third controller controls the operation of the solid-liquid separation module, the waste solid harmless treatment module, and the waste solid transportation module according to the amount of sediment and the liquid level in the buffer module.

[0020] Optionally, the aquaculture pond is equipped with an automatic water replenishment device, and the recirculating aquaculture system further includes: a water source replenishment unit connected to the automatic water replenishment device, the water source replenishment unit being used to provide replenishment water to the aquaculture pond, and the water source replenishment unit being connected to the solid-liquid separation unit.

[0021] Optionally, the water supply unit includes:

[0022] A reservoir is used to store replenished water.

[0023] A booster module, the inlet of which is connected to the outlet of the water storage tank;

[0024] The second sand filter module has its inlet connected to the outlet of the pressurization module, its first outlet connected to the second disinfection and sterilization module, and its second outlet connected to the buffer module.

[0025] A pressure stabilization module, the inlet of which is connected to the outlet of the second disinfection and sterilization module, and the outlet of which is connected to the automatic water replenishment device;

[0026] The fourth controller is connected to the pressure stabilization module, the pressurization module, the second sand filter module, and the second disinfection and sterilization module respectively. The fourth controller controls the operation of the pressurization module, the second sand filter module, and the second disinfection and sterilization module according to the pressure of the pressure stabilization module.

[0027] Optionally, the denitrification unit includes: a coarse particle filtration module, a fine particle and dissolved organic matter separation module, a first sand filter module, a first disinfection and sterilization module, a nitrifying bacteria cultivation module, and a water temperature and dissolved oxygen control module connected in sequence. The inlet of the coarse particle filtration module is connected to the central suspended solids drain pipe via a water pump, and the outlet of the water temperature and dissolved oxygen control module is connected to the water pushing device. The coarse particle filtration module, the fine particle and dissolved organic matter separation module, and the first sand filter module are also connected to the buffer module. The first sand filter module is also used to receive the water discharged from the solid-liquid separation module.

[0028] The denitrification unit further includes a first controller, which is connected to the water pump, the coarse particle filtration module, the fine particle and dissolved organic matter separation module, the first sand filter module, the first disinfection and sterilization module, the nitrifying bacteria cultivation module, and the water temperature and dissolved oxygen control module. The first controller controls the operation of the water pump, the coarse particle filtration module, the fine particle and dissolved organic matter separation module, the first sand filter module, the first disinfection and sterilization module, the nitrifying bacteria cultivation module, and the water temperature and dissolved oxygen control module based on the data in the nitrifying bacteria cultivation module and the information in the water temperature and dissolved oxygen control module.

[0029] Optionally, the carbon-nitrogen ratio coordination unit includes: a second controller, a trace element control module, a heterotrophic microorganism control module, and a carbon-nitrogen ratio adjustment module. The second controller is also connected to a first sensor in the aquaculture pond. The second controller controls the operation of the trace element control module, the heterotrophic microorganism control module, and the carbon-nitrogen ratio adjustment module according to the trace element content, floc content, and ammonia nitrogen concentration in the aquaculture pond. The outlets of the trace element control module, the heterotrophic microorganism control module, and the carbon-nitrogen ratio adjustment module are connected to the Venturi tube at the outlet of the water temperature and dissolved oxygen control module, and after mixing with the water from the denitrification unit, they enter the aquaculture pond through the water-pushing device.

[0030] The first sensor is used to acquire information on the content of trace elements, suspended solids, and ammonia nitrogen in the aquaculture pond.

[0031] Optionally, the recirculating aquaculture system further includes a feeding unit connected to the aquaculture pond, wherein the feeding unit provides feed to the aquaculture pond according to the content of residual feed and suspended solids in the aquaculture pond;

[0032] The fabric unit includes:

[0033] Feed bins are used to store bait;

[0034] A feeder, the inlet of which is connected to the outlet of the feed hopper, and the outlet of which is connected to the aquaculture pond;

[0035] The fifth controller is connected to the second sensor in the aquaculture pond and the feeder respectively. The fifth controller controls the operation of the feeder according to the content of residual feed and suspended solids in the aquaculture pond, so as to put the feed in the feed bin into the aquaculture pond.

[0036] The second sensor is used to acquire information on the content of residual feed and suspended matter in the aquaculture pond.

[0037] On the other hand, the present invention provides a recirculating aquaculture method, the recirculating aquaculture method comprising the following steps:

[0038] Provide driving force for the water in the aquaculture pond;

[0039] A portion of the water in the aquaculture pond is denitrified, and the denitrified water is then discharged back into the aquaculture pond.

[0040] Monitor the content of growth elements required by aquatic products in the aquaculture pond. If the content of the growth elements is less than the first set threshold, supply the growth elements to the aquaculture pond. If the content of the growth elements is not less than the first set threshold, stop supplying the growth elements to the aquaculture pond.

[0041] The sediment in the aquaculture pond is subjected to solid-liquid separation treatment. The supernatant is transported to the denitrification unit for denitrification treatment and then discharged back into the aquaculture pond, while the waste solids are discharged.

[0042] The feed content in the aquaculture pond is monitored. When the feed content is less than a second set threshold, feed is supplied to the aquaculture pond. When the feed content is not less than the second set threshold, the supply of feed to the aquaculture pond is stopped.

[0043] Optionally, monitoring the content of growth elements required by aquatic products in the aquaculture pond includes the following steps:

[0044] When the content of at least one of trace elements, bacterial flocs and carbon in the aquaculture pond is lower than the corresponding first set threshold, the corresponding modules are activated to add at least one of the trace elements, bacterial flocs and carbon sources configured in proportion to the aquaculture pond. The added trace elements, bacterial flocs and carbon sources enter the aquaculture pond together with the denitrified water.

[0045] The beneficial effects of the technical solution provided by this invention include at least the following:

[0046] The inlet and outlet of the denitrification unit are directly connected to the aquaculture pond to achieve denitrification treatment of the water in the pond. This effectively reduces the footprint of existing RAS aquaculture water treatment systems. On the one hand, it reduces the area of ​​the water treatment unit in the coupled recirculating aquaculture system, thereby increasing the area of ​​the aquaculture pond and improving aquaculture efficiency. On the other hand, it also reduces the amount of aquaculture water to be treated and improves the water circulation efficiency. At the same time, the carbon-nitrogen ratio coordination unit can add the growth elements required for aquaculture to the circulating water, ensuring the lifespan and quality of aquatic products. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 A schematic diagram of a coupled recirculating aquaculture system according to an embodiment of the present invention is shown;

[0049] Figure 2 A schematic diagram of a denitrification unit according to an embodiment of the present invention is shown;

[0050] Figure 3A schematic diagram of a carbon-nitrogen ratio coordinating unit according to an embodiment of the present invention is shown;

[0051] Figure 4 A schematic diagram of a solid-liquid separation unit according to an embodiment of the present invention is shown;

[0052] Figure 5 A schematic diagram of a water supply unit according to an embodiment of the present invention is shown;

[0053] Figure 6 A schematic diagram of a fabric system according to an embodiment of the present invention is shown;

[0054] Figure 7 A flowchart illustrating the steps of a recirculating aquaculture method according to an embodiment of the present invention is shown.

[0055] in, Figures 1 to 6 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0056] 10. Aquaculture pond; 11. Central bottom drain pipe; 12. Central suspended solids drain pipe; 13. Water pushing device; 14. Automatic water replenishment device; 15. First sensor; 16. Second sensor; 20. Denitrification unit; 21. First controller; 22. Water pump; 23. Coarse particle filtration module; 24. Fine particle and dissolved organic matter separation module; 25. First sand filter module; 26. First disinfection and sterilization module; 27. Nitrifying bacteria cultivation module; 28. Water temperature and dissolved oxygen control module; 30. Carbon-nitrogen ratio coordination unit; 31. Second controller; 32. Micro-scale... Element control module, 33 heterotrophic microorganism control module, 34 carbon-nitrogen ratio adjustment module, 40 solid-liquid separation unit, 41 third controller, 42 buffer module, 43 solid-liquid separation module, 44 waste solid harmless treatment module, 45 waste solid external transportation module, 50 water source replenishment unit, 51 fourth controller, 52 water storage tank, 53 pressurization module, 54 second sand filter module, 55 second disinfection and sterilization module, 56 pressure stabilization module, 60 material distribution unit, 61 fifth controller, 62 silo, 63 material distributor.

[0057] The accompanying drawings illustrate several specific embodiments of the present invention, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0058] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0059] Before providing a further detailed description of the embodiments of the present invention, the directional terms used in the embodiments of the present invention, such as "upper part", "lower part" and "side part", are not intended to limit the scope of protection of the present invention.

[0060] To make the technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0061] Example 1

[0062] Figure 1 A schematic diagram of a coupled recirculating aquaculture system according to an embodiment of the present invention is shown;

[0063] like Figure 1 As shown, this embodiment provides a coupled recirculating aquaculture system, which includes:

[0064] Aquaculture pond 10 is used for aquaculture. Aquaculture pond 10 is equipped with a central suspended solids drain pipe 12 and a water pushing device 13.

[0065] The denitrification unit 20 has its inlet connected to the central suspended solids drain pipe 12 and its outlet connected to the water pusher 13. The denitrification unit 20 is used to denitrify the water and then sends the denitrified water back to the aquaculture pond 10 through the water pusher 13.

[0066] The carbon-nitrogen ratio coordination unit 30 is connected between the water pushing device 13 and the denitrification unit 20. The carbon-nitrogen ratio coordination unit 30 adjusts the content of growth elements in the water entering the aquaculture pond 10 in a timely manner according to the changes in the growth elements required by the aquatic products in the aquaculture pond 10. At the same time, it is sent into the aquaculture pond 10 together with the water discharged from the denitrification unit 20 through the water pushing device 13.

[0067] The denitrification unit 20 is directly connected to the aquaculture pond 10 through its inlet and outlet, enabling denitrification of the water in the aquaculture pond 10. This reduces the floor space occupied by other units in the aquaculture workshop, i.e., reduces the non-aquaculture area. On the one hand, this helps save construction costs and improves the economics of the recirculating aquaculture system. On the other hand, it frees up more space to build more aquaculture ponds 10, increasing the output of aquaculture. It can also reduce the daily aquaculture water treatment volume to less than 1 / 3 of that of the RAS aquaculture system. Without affecting the area of ​​the aquaculture pond 10, it ensures water circulation without the need for additional water replenishment. This makes it suitable for aquaculture workshops in the Yellow River Basin during the non-irrigation season, thus expanding the applicability of the water circulation system.

[0068] It should be noted that the existing RAS aquaculture system's water treatment unit cannot consistently meet water quality standards. Therefore, the water treatment unit needs to be set up separately from the aquaculture pond 10, and the water can only be recycled after it meets the standards. Furthermore, the existing water treatment unit uses traditional biological filters, generally employing the activated sludge process, which has a large footprint and relatively limited water treatment efficiency. The denitrification unit 20 used in this application employs an autotrophic nitrification filter, which provides more stable water treatment, occupies a smaller footprint, and has a unit water treatment capacity three times that of traditional biological filters.

[0069] Specifically, the denitrification process in the aquaculture pond 10 is directly achieved by connecting the central suspended solids drain pipe 12 to the inlet of the denitrification unit 20 and the water pusher 13 to the outlet of the denitrification unit 20. This effectively removes suspended solids and organic matter from the water in the aquaculture pond 10, removes assimilating microorganisms and algae, reduces the ammonia nitrogen content in the water, and ensures the lifespan of aquatic products in the aquaculture pond 10. The same water pump 22 can be used at both the inlet and outlet of the denitrification unit 20, further reducing the area of ​​the denitrification unit 20. The carbon-nitrogen ratio coordination unit 30 can also add trace elements required for aquaculture to the circulating water, ensuring the lifespan and quality of aquatic products.

[0070] The aquaculture pond 10 can also be used for aerobic nitrification of nitrogen compounds and partial oxygen-enriched denitrification. Some heterotrophic microorganisms, similar microorganisms, nitrifying microorganisms and aerobic denitrifying microorganisms need to be introduced into the aquaculture pond 10 in advance. Among them, the heterotrophic microorganisms are responsible for hydrolyzing organic matter such as proteins in uneaten feed and metabolites into amino acids, which are then converted into biological cell nitrogen and deammoniated into nitrogen by the assimilating microorganisms. Then, the nitrifying microorganisms convert ammonia nitrogen into nitrite (intermediate, which is later converted into nitrate) and nitrate. Some of the nitrate is absorbed as nutrients for algae, and some of the nitrate is converted into solid nitrogen and / or gaseous nitrogen by the aerobic denitrifying microorganisms. The solid nitrogen is then treated by the solid-liquid separation unit 40, and the gaseous nitrogen can be directly discharged from the water body.

[0071] Furthermore, the coupled recirculating aquaculture system maintains a low concentration of ammonia nitrogen in the water of the aquaculture pond 10 through the denitrification unit 20, thus stabilizing the water quality within the pond 10. As part of the coupled recirculating aquaculture system, the denitrification unit 20 eliminates the need for an additional water treatment system outside the pond 10, reducing the area of ​​the coupled recirculating aquaculture system. The carbon-nitrogen ratio coordination unit 30 replenishes the recirculating water with trace elements required for aquaculture, ensuring the lifespan and quality of the aquatic products.

[0072] In one feasible embodiment, the aquaculture pond 10 is also provided with a central bottom drain pipe 11, and the recirculating aquaculture system also includes a solid-liquid separation unit 40, which is connected to the central bottom drain pipe 11. The water passing through the solid-liquid separation unit 40 enters the denitrification unit 20, and the solid waste passing through the solid-liquid separation unit 40 is discharged from the solid-liquid separation unit 40.

[0073] The solid-liquid separation unit 40 is used to remove sediment from the water in the aquaculture pond 10, preventing further hydrolysis and nitrogenization of organic matter, ensuring a balanced ammonia nitrogen content in the water of the aquaculture pond 10, thereby reducing the workload of the denitrification unit 20 and increasing the service life of the coupled recirculating aquaculture system. By separating solid harmful components in the circulating water through the solid-liquid separation unit 40, the regeneration of harmful ions in the water environment is solved at the source, ensuring the stable operation of the subsequent denitrification unit 20.

[0074] Figure 4 A schematic diagram of a solid-liquid separation unit according to an embodiment of the present invention is shown.

[0075] In one feasible embodiment, such as Figure 4 As shown, the solid-liquid separation unit 40 includes:

[0076] The buffer module 42 is connected to the central bottom drain pipe 11 and the denitrification unit 20. The buffer module 42 is used to receive the sediment water of the aquaculture pond 10 and the sewage discharged from the denitrification unit 20.

[0077] The solid-liquid separation module 43 has its inlet connected to the buffer module 42 and its first outlet connected to the denitrification unit 20.

[0078] Waste solid harmless treatment module 44, the inlet of waste solid harmless treatment module 44 is connected to the second outlet of solid-liquid separation;

[0079] Waste and solid waste transportation module 45 is connected to the outlet of waste and solid waste harmless treatment module 44;

[0080] The third controller 41 is connected to the buffer module 42, the solid-liquid separation module 43, the waste solid harmless treatment module 44, and the waste solid transportation module 45 respectively. The third controller 41 controls the operation of the solid-liquid separation module 43, the waste solid harmless treatment module 44, and the waste solid transportation module 45 according to the amount of sediment and the liquid level in the buffer module 42.

[0081] Specifically, based on the material distribution time and after an appropriate delay (when sediment begins to form), the solid-liquid separation module 43 is activated via the third controller 41 until the sediment content in the buffer module 42 decreases to a set threshold. The sediment content in the buffer module 42 serves as a reference for the solid-liquid separation module 43. When the sediment content in the buffer module 42 is lower than the set threshold, it indicates that the suspended solids concentration has decreased, and the operating load of the solid-liquid separation module 43 can be increased, i.e., the processing of solid-liquid separation can be intensified. At this time, the operating pressure of the entire coupled recirculating aquaculture system can be reduced, i.e., the amount of various microorganisms introduced into the aquaculture pond 10 by the denitrification unit 20 and the carbon-nitrogen ratio coordination unit 30 can be increased. The sediment content in the buffer device is reduced accordingly (the measurement of sediment content in the buffer device can be transmitted to the third controller 41 via a turbidity meter); when the water retention time of the solid-liquid separation module 43 is satisfied, the supernatant discharge pump in the solid-liquid separation module 43 is turned on, and the supernatant is discharged into the denitrification unit 20 (the first sand filter module 25 of the denitrification unit 20) for denitrification treatment and then discharged back into the aquaculture pond 10. After the supernatant is discharged, the waste solid harmless treatment module 44 is turned on through the third controller 41, and the waste solid is treated in combination with the utilization and destination of the waste solid. For example, when used as water fertilizer, the salinity is directly diluted and reduced. The treated waste solid is sent to the power plant for incineration through the waste solid transportation module 45 for subsequent dehydration and other treatments.

[0082] Furthermore, the buffer module 42 is also equipped with a liquid level sensor. This sensor prevents the liquid level in the buffer module 42 from becoming too low during the operation of the solid-liquid separation module 43, which could cause all the water in the aquaculture pond 10 to flow into the buffer module 42, affecting the normal operation of the entire coupled recirculating aquaculture system. It should be noted that the central bottom drain pipe 11 is connected to the buffer module 42 via a pipeline. By periodically lowering the water level in the buffer module 42, intermittent drainage of sediment at the bottom of the aquaculture pond 10 is achieved. When no drainage is being performed, the water level in the buffer module 42 remains the same as the water level in the aquaculture pond 10. The drain pipes from the denitrification unit 20 and the water supply unit 50 have one-way valves to prevent backflow into the denitrification unit 20 and the water supply unit 50 caused by a high water level in the buffer module 42.

[0083] It should be noted that a one-way valve needs to be installed between the central bottom drain pipe 11 and the buffer module 42 to prevent free exchange of water between the buffer module 42 and the aquaculture pond 10, avoid water environment fluctuations, and facilitate the stable operation of subsequent units.

[0084] In one feasible embodiment, the aquaculture pond 10 is equipped with an automatic water replenishment device 14, and the recirculating aquaculture system further includes a water source replenishment unit 50 connected to the automatic water replenishment device 14. The water source replenishment unit 50 is used to provide replenishment water to the aquaculture pond 10, and the water source replenishment unit 50 is also connected to the solid-liquid separation unit 40.

[0085] The water source replenishment unit 50 can provide water to the aquaculture pond 10. The water source replenishment unit 50 is connected to the automatic water replenishment device 14 through a venturi tube. According to the working principle of the venturi tube, the water in the pipe is pressurized and can flow into the aquaculture pond 10, realizing automatic water replenishment in the aquaculture pond 10 without power (no need to add an additional water pump 22). It should be noted that multiple aquaculture ponds 10 can use the same water source replenishment unit 50, further saving the area of ​​the coupled recirculating aquaculture system and increasing the aquaculture yield.

[0086] It should be noted that a portion of the water source in the water supply unit 50 is treated by the solid-liquid separation unit 40 before flowing into the aquaculture pond 10. This is to prevent excessive suspended solids and organic matter from entering the aquaculture pond 10, which could lead to untimely processing by the coupled recirculating aquaculture system and affect the water quality in the aquaculture pond 10.

[0087] Figure 5 A schematic diagram of a water supply unit according to an embodiment of the present invention is shown.

[0088] In one feasible embodiment, such as Figure 5 As shown, the water supply unit 50 includes:

[0089] Water storage tank 52 is used to store replenishment water;

[0090] The booster module 53 has its inlet connected to the outlet of the water storage tank 52;

[0091] The inlet of the second sand filter module 54 is connected to the outlet of the booster module 53, the first outlet of the second sand filter module 54 is connected to the second disinfection and sterilization module 55, and the second outlet of the second sand filter module 54 is connected to the buffer module 42.

[0092] Pressure stabilization module 56, the inlet of pressure stabilization module 56 is connected to the outlet of second disinfection and sterilization module 55, and the outlet of pressure stabilization module 56 is connected to automatic water replenishment device 14.

[0093] The fourth controller 51 is connected to the pressure stabilization module 56, the pressurization module 53, the second sand filter module 54, and the second disinfection and sterilization module 55 respectively. The fourth controller 51 controls the operation of the pressurization module 53, the second sand filter module 54, and the second disinfection and sterilization module 55 according to the pressure of the pressure stabilization module 56.

[0094] The reservoir 52 is used to store the original replenishment water. The water temperature and trace elements in the reservoir 52 should meet the requirements of aquaculture. The pressure stabilization module 56 obtains the water pressure of the coupled recirculating aquaculture system. The fourth controller 51 controls the pressurization module 53 to open and close according to the water pressure, so that the pressure required by the water source replenishment unit 50 meets the pressure requirements of the coupled recirculating aquaculture system. Then, the original replenishment water is filtered by the second sand filter module 54 to remove suspended solids and algae. The second disinfection and sterilization module 55 continues to disinfect and sterilize the replenishment water.

[0095] It should be noted that suspended solids and algae are removed physically through the second sand filter module 54, while the second disinfection and sterilization module 55 disinfects and sterilizes the water through the strong oxidizing effect of ozone.

[0096] Figure 2 A schematic diagram of a denitrification unit according to an embodiment of the present invention is shown.

[0097] In one feasible embodiment, such as Figure 2 As shown, the denitrification unit 20 includes: a coarse particle filtration module 23, a fine particle and dissolved organic matter separation module 24, a first sand filter module 25, a first disinfection and sterilization module 26, a nitrifying bacteria cultivation module 27, and a water temperature and dissolved oxygen control module 28 connected in sequence. The inlet of the coarse particle filtration module 23 is connected to the central suspended solids drain pipe 12 via a water pump 22, and the outlet of the water temperature and dissolved oxygen control module 28 is connected to the water pusher 13. The coarse particle filtration module 23, the fine particle and dissolved organic matter separation module 24, and the first sand filter module 25 are also connected to the buffer module 42. The first sand filter module 25 is also used to receive the water discharged from the solid-liquid separation module 43.

[0098] The denitrification unit 20 also includes a first controller 21, which is connected to a water pump 22, a coarse particle filtration module 23, a fine particle and dissolved organic matter separation module 24, a first sand filter module 25, a first disinfection and sterilization module 26, a nitrifying bacteria cultivation module 27, and a water temperature and dissolved oxygen control module 28. The first controller 21 controls the operation of the water pump 22 and the operation of the coarse particle filtration module 23, the fine particle and dissolved organic matter separation module 24, the first sand filter module 25, the first disinfection and sterilization module 26, the nitrifying bacteria cultivation module 27, and the water temperature and dissolved oxygen control module 28 based on the data in the nitrifying bacteria cultivation module 27 and the information in the water temperature and dissolved oxygen control module 28.

[0099] The first controller 21 receives information from the nitrifying bacteria cultivation module 27 and the water temperature and dissolved oxygen control module 28, and controls the operation of the water pump 22, the coarse particle filtration module 23, the fine particle and dissolved organic matter separation module 24, the first sand filter module 25, the first disinfection and sterilization module 26, the nitrifying bacteria cultivation module 27, and the water temperature and dissolved oxygen control module 28. It should be noted that the water body coming out of the aquaculture pond 10 and the water body returning to the aquaculture pond 10 after denitrification treatment are both powered by the water pump 22.

[0100] It should be noted that the water pushing device 13 receives the water output from the water temperature and dissolved oxygen control module 28 in the denitrification unit 20, and pushes the water in the aquaculture pond 10 to move at a certain speed, so that the sediment at the bottom of the aquaculture pond 10 moves towards the center of the aquaculture pond 10, thereby improving the sewage discharge efficiency of the central bottom sewage pipe 11.

[0101] Furthermore, the first controller 21 acquires the ORP, pH, and ammonia nitrogen (microbial data) content data in the nitrifying bacteria culture module 27 to control the amount of water flowing from the water pump 22 to the coarse particle filter module 23; the first controller 21 acquires the dissolved oxygen content and water temperature data information in the water temperature and dissolved oxygen control module 28 to control the air supply pressure of the water temperature and dissolved oxygen control module 28.

[0102] ORP (Oxidation-Reduction Potential) is a comprehensive indicator of the redox state of an aquatic environment. Generally, a low ORP value indicates a high concentration of reducing substances or organic pollutants and a low dissolved oxygen concentration in the wastewater treatment system, indicating a dominant reducing environment. Conversely, a high ORP value indicates a low concentration of organic pollutants and a high concentration of dissolved oxygen or oxidizing substances, indicating a dominant oxidizing environment. It should be noted that ORP is obtained using an oxidation-reduction potential sensor.

[0103] Specifically, when the water temperature in the water temperature and dissolved oxygen control module 28 is below 25°C, or the dissolved oxygen content at the inlet of the water temperature and dissolved oxygen control module 28 is below 4.5 mg / L, or the atmospheric pressure is below 100 kPa, the flow rate of the water pump 22 to the water temperature and dissolved oxygen control module 28 needs to be increased. Specifically, the heating module is turned on when the water temperature is low (below 25°C) and turned off when the water temperature is above 28°C. When the ammonia nitrogen and nitrate content at the inlet of the nitrifying bacteria culture module 27 are close to the control threshold, or the suspended solids content in the aquaculture pond 10 is close to the control threshold, the flow rate of the water pump 22 to the coarse particle filter module 23 is increased. When both of the above conditions are met simultaneously, the operating frequency of the water pump 22 is increased, and according to the water level information of the buffer module 42 in the solid-liquid separation unit 40 (read from the third controller 41), the drain valves of the coarse particle filter module 23, the fine particle and dissolved organic matter separation module 24, and the first sand filter module 25 are opened periodically to discharge sewage into the buffer module 42. The ammonia nitrogen and nitrate content were obtained using ammonia nitrogen and nitrate sensors, while the suspended solids content was obtained using a turbidity meter.

[0104] It should be noted that the coarse particle filtration module 23 is used to filter suspended solids larger than 100 micrometers (in a suspended state in water, such as silt, clay, algae, bacteria, and other insoluble substances) entering the denitrification unit 20. The fine particle and dissolved organic matter separation module 24 is used to further filter suspended solids smaller than 100 micrometers and dissolved organic matter (colloidal substances in water, of which inorganic colloids are mainly secondary clay minerals and various water-containing oxides, and organic colloids are mainly humic acid). After passing through the first sand filtration module 25, the dissolved substances with a particle size of less than 1 micrometer are further filtered (in a dissolved state as molecules or ions in water, including various salts, gases, and certain organic compounds). The water without suspended solids is disinfected and sterilized by the first disinfection and sterilization module 26 and then sent to the nitrifying bacteria cultivation module 27. The nitrifying bacteria cultivation module 27 performs biological denitrification on the filtered water and cultivates nitrifying bacteria. Then, the water rich in nitrifying bacteria is sent back to the aquaculture pond 10 after passing through the water temperature and dissolved oxygen control module 28, which is used to continuously inject nitrifying microorganisms into the aquaculture pond 10. The denitrification unit 20 removes suspended solids and organic matter from the water through physical means, removes assimilating microorganisms and algae, reduces some of the ammonia nitrogen content in the water, and then removes the remaining ammonia nitrogen and some nitrates through nitrification to achieve comprehensive denitrification. Finally, the water temperature and dissolved oxygen control module 28 controls the dissolved oxygen and temperature of the denitrified water to meet the requirements of aquaculture for water temperature and oxygen content, thereby improving the yield and quality of aquatic products. Specifically, the oxygen content in the water entering the aquaculture pond 10 must be sufficiently abundant to support the full reaction of various microorganisms with organic matter in the water, improve denitrification efficiency, and maintain the stability of the water quality in the aquaculture pond 10.

[0105] Figure 3A schematic diagram of a carbon-nitrogen ratio coordination unit according to an embodiment of the present invention is shown.

[0106] In one feasible embodiment, such as Figure 3 As shown, the carbon-nitrogen ratio coordination unit 30 includes: a second controller 31, a trace element control module 32, a heterotrophic microorganism control module 33, and a carbon-nitrogen ratio adjustment module 34. The second controller 31 is also connected to the first sensor 15 in the aquaculture pond 10. The second controller 31 controls the operation of the trace element control module 32, the heterotrophic microorganism control module 33, and the carbon-nitrogen ratio adjustment module 34 according to the trace element content, bacterial floc content, and ammonia nitrogen concentration in the aquaculture pond 10. The outlets of the trace element control module 32, the heterotrophic microorganism control module 33, and the carbon-nitrogen ratio adjustment module 34 are connected to the Venturi tube at the outlet of the water temperature and dissolved oxygen control module 28, and after mixing with the water in the denitrification unit 20, they enter the aquaculture pond 10 through the water pusher 13.

[0107] The first sensor 15 is used to acquire information on the content of trace elements, the content of bacterial flocs and the concentration of ammonia nitrogen in the aquaculture pond 10. Ammonia nitrogen concentration is one of the pollution indicators of water bodies and has a significant impact on aquaculture. Ammonia nitrogen in aquaculture mainly comes from uneaten feed, metabolic products of farmed animals and the remains of aquatic plants and animals. The concentration of ammonia nitrogen can be obtained by the ammonia nitrogen sensor.

[0108] It should be noted that the first sensor 15 acquires at least one content value of trace elements, bacterial flocs (heterotrophic microorganisms), and ammonia nitrogen concentration in the aquaculture pond 10. When the content value is lower than the control threshold, the second controller 31 activates the corresponding trace element control module 32, heterotrophic microorganism control module 33, and carbon-nitrogen ratio adjustment module 34 respectively, so that the information of trace element content, suspended solids content, and ammonia nitrogen concentration in the aquaculture pond 10 meets the needs of aquaculture.

[0109] Among them, the content of trace elements is obtained by a trace element analyzer, the content of bacterial flocs (heterotrophic microorganisms) is obtained by the plate method, and the carbon-nitrogen ratio is obtained by calculating the carbon and nitrogen content in the water. The trace element control module 32 adds the trace element solution prepared in a certain proportion to the aquaculture pond 10 through a peristaltic pump. The heterotrophic microorganism control module 33 is usually equipped with freeze-dried heterotrophic microorganism powder, which is added to the aquaculture pond 10 through a metering valve. The carbon-nitrogen ratio adjustment module 34 delivers external carbon and nitrogen sources to the aquaculture pond 10 through a peristaltic pump to maintain an optimal carbon-nitrogen ratio in the aquaculture environment.

[0110] It should be noted that trace elements such as calcium, magnesium, phosphorus, and potassium are necessary for the growth of fish and shrimp. Water that has been repeatedly filtered lacks the corresponding trace elements and needs to be supplemented. Heterotrophic microorganisms can grow rapidly in a nutrient-rich environment and are responsible for hydrolyzing organic matter such as proteins in uneaten feed and metabolites into amino acids.

[0111] The role of nitrifying bacteria is to remove harmful ammonia nitrogen from the water. However, the number of nitrifying bacteria in the water environment is usually very small, basically zero. Therefore, the nitrifying microorganisms in the nitrifying bacteria culture module 27 are put into the aquaculture pond 10 to treat the water quality in the aquaculture pond 10.

[0112] Furthermore, after repeated filtration, the content of trace elements in the water of the aquaculture pond 10 is reduced, affecting the quality of aquatic product cultivation. The trace element control module 32 adjusts the concentration of trace elements in the water environment and the ratio between various components to meet the needs of aquatic product growth. The heterotrophic microorganism control module 33 adjusts the content of assimilating microorganisms in the aquaculture pond 10, so that the concentration of organic matter and ammonia nitrogen can be controlled more quickly, avoiding the accumulation of organic matter and ammonia nitrogen and improving the efficiency of water treatment. The carbon-nitrogen ratio adjustment module 34 can control the number of a certain type of microorganism and the growth of algae. These control and adjustment components enter the aquaculture pond 10 through the water-pushing device 13 and can diffuse rapidly, meeting the requirements of aquatic product cultivation for water quality.

[0113] Figure 6 A schematic diagram of a fabric unit according to an embodiment of the present invention is shown.

[0114] In one feasible embodiment, such as Figure 6 As shown, the recirculating aquaculture system also includes a feeding unit 60, which is connected to the aquaculture pond 10. The feeding unit 60 provides feed to the aquaculture pond 10 according to the content of residual feed and suspended solids in the aquaculture pond 10.

[0115] Fabric unit 60 includes:

[0116] Feed bin 62 is used to store bait;

[0117] The feeder 63 has its inlet connected to the outlet of the feed hopper 62, and its outlet connected to the aquaculture pond 10.

[0118] The fifth controller 61 is connected to the second sensor 16 and the feeder 63 in the breeding pond 10 respectively. The fifth controller 61 controls the operation of the feeder 63 according to the content of residual feed and suspended matter in the breeding pond 10, and feeds the feed in the feed bin 62 into the breeding pond 10.

[0119] The second sensor 16 is used to obtain information on the content of residual feed and suspended matter in the aquaculture pond 10.

[0120] It should be noted that the content of residual feed and suspended matter in the aquaculture pond 10 is obtained by the second sensor 16. When it is lower than the control threshold, the feed in the feed bin 62 is distributed into the aquaculture pond 10 by the feed distributor 63 controlled by the fifth controller 61 to meet the feed demand of aquaculture in the aquaculture pond 10.

[0121] Furthermore, the second sensor 16 includes a suspended matter sensor and a sediment sensor. If the content of sediment and suspended matter remains at a high level, untreated feed will undergo ammonification, continuously releasing harmful ions such as ammonia nitrogen into the aquatic environment, which will affect aquaculture.

[0122] It should be noted that the central bottom drain pipe 11 in the aquaculture pond 10 is used to promptly remove bottom sediments, including uneaten feed and metabolites, and send them to the solid-liquid separation unit 40 for solid-liquid separation treatment; the central suspended solids drain pipe 12 is used to remove uneaten feed, metabolites, assimilating heterotrophic microorganisms, algae and other organic matter that have not yet settled, and is the water source for the denitrification unit 20; the water pushing device 13 receives the water body after denitrification from the denitrification unit 20, and pushes the water body in the aquaculture pond 10 to move at a certain speed, so that the bottom sediments move towards the center of the aquaculture pond 10, thereby improving the sewage discharge efficiency of the central bottom drain pipe 11; the automatic water replenishment device 14 is driven by the water source replenishment unit 50 and is used to maintain the water level in the aquaculture pond 10. Most of the uneaten feed and metabolites in the aquatic environment of the breeding pond 10 are removed from the aquatic environment after passing through the solid-liquid separation unit 40. A small amount of organic matter is absorbed and utilized by heterotrophic microorganisms and converted into cellular nitrogen and ammonia nitrogen. The cellular nitrogen is separated again by the solid-liquid separation unit 40. The ammonia nitrogen is converted into nitrate by nitrifying microorganisms. The nitrate is absorbed and utilized as a nutrient for algae.

[0123] Among them, the aquaculture pond 10, the denitrification unit 20, and the carbon-nitrogen ratio coordination unit 30 are for the treatment of suspended solids and denitrification, and the solid-liquid separation unit 40 discharges the sediment to prevent further hydrolysis and nitrogenization of organic matter in the water. These four units work together to ensure the water quality in the aquaculture pond 10, which is more conducive to the aquaculture of aquatic products.

[0124] Furthermore, in the coupled recirculating aquaculture system, the first controller 21 to the fifth controller 61 are connected through a local network and share the sensor information they collect as network variables, meaning they can read each other's data. In other words, the data transmission between the controllers and the sensors and measuring instruments is controlled by programming and can be customized. This is not the content protected by this application and will not be elaborated further. The controllers in each unit are connected to the modules in the unit through cables, and the modules in the unit are connected end to end by pipes, with the arrows indicating the direction of water flow.

[0125] Example 2

[0126] like Figure 7 As shown in the figure, this embodiment provides a recirculating aquaculture system (RAS) method, which includes the following steps:

[0127] Step 1: Provide driving force for the water in the aquaculture pond;

[0128] Step 2: Denitrify a portion of the water in the aquaculture pond and then discharge the denitrified water back into the aquaculture pond.

[0129] Step 3: Monitor the content of growth elements required by aquatic products in the aquaculture pond. If the content of growth elements is less than the first set threshold, supply growth elements to the aquaculture pond. If the content of growth elements is not less than the first set threshold, stop supplying growth elements to the aquaculture pond.

[0130] Step 4: Perform solid-liquid separation treatment on the sediment water in the aquaculture pond, transport the supernatant to the denitrification unit for denitrification treatment and then discharge it back into the aquaculture pond, and discharge the waste solids.

[0131] Step 5: Monitor the feed content in the aquaculture pond. When the feed content is less than the second set threshold, feed is delivered to the aquaculture pond. When the feed content is not less than the second set threshold, feed delivery to the aquaculture pond is stopped.

[0132] Specifically, in step 1, the aquaculture pond is replenished with water and driven by the water source replenishment unit. The water storage tank is used to store the original replenishment water. The water temperature and trace elements in the water storage tank should meet the requirements of aquaculture. The pressure stabilization module obtains the water pressure of the coupled recirculating aquaculture system. The fourth controller controls the pressurization module to open and close according to the water pressure, so that the pressure required by the water source replenishment unit meets the pressure requirements of the coupled recirculating aquaculture system. Then, the original replenishment water is filtered by the second sand filter module to remove suspended solids and algae. The second disinfection and sterilization module continues to disinfect and sterilize the replenishment water.

[0133] It should be noted that suspended solids and algae are physically removed through the second sand filtration module, while the second disinfection and sterilization module disinfects and sterilizes the water through the strong oxidizing properties of ozone.

[0134] In step 2, denitrification is achieved through a denitrification unit. When the water temperature in the water temperature and dissolved oxygen control module is below 25°C, or the dissolved oxygen content at the inlet of the water temperature and dissolved oxygen control module is below 4.5 mg / L, or the atmospheric pressure is below 100 kPa, the flow rate of the water pump to the water temperature and dissolved oxygen control module needs to be increased. Specifically, the heating module is turned on when the water temperature is low (below 25°C, 28°C) and turned off when the temperature is above 28°C. When the ammonia nitrogen and nitrate content at the inlet of the nitrifying bacteria culture module are close to the control threshold, or the suspended solids content in the aquaculture pond is close to the control threshold, the flow rate of the water pump to the coarse particle filter module is increased. When both of the above conditions are met simultaneously, the operating frequency of the water pump is increased, and according to the water level information of the buffer module in the solid-liquid separation unit (read from the third controller), the drain valves of the coarse particle filter module, the fine particle and dissolved organic matter separation module, and the first sand filter module are opened periodically to discharge wastewater into the buffer module. The ammonia nitrogen and nitrate content is obtained through ammonia nitrogen and nitrate sensors, and the suspended solids content is obtained through a turbidity meter.

[0135] In step 3, growth elements are delivered through the carbon-nitrogen ratio coordination unit. The first sensor acquires at least one content value among trace elements, suspended solids, and ammonia nitrogen concentrations in the aquaculture pond. When the content value is lower than the control threshold, the second controller activates the corresponding trace element control module, heterotrophic microorganism control module, and carbon-nitrogen ratio adjustment module, thereby ensuring that the information on trace element content, suspended solids content, and ammonia nitrogen concentration in the aquaculture pond meets the requirements of aquaculture.

[0136] In step 4, solid-liquid separation is achieved through a solid-liquid separation unit. Based on the material distribution time and after an appropriate delay (when sediment begins to form), the solid-liquid separation module is activated via a third controller until the sediment content in the buffer module decreases to a set threshold. The sediment content in the buffer module serves as a reference for the solid-liquid separation module. When the sediment content in the buffer module falls below the set threshold, it indicates a decrease in suspended solids concentration, allowing the solid-liquid separation module to operate at a higher load, thus increasing the solid-liquid separation treatment. At this point, the operating pressure of the entire water treatment system can be reduced, allowing the denitrification unit and the carbon-nitrogen ratio coordination unit to introduce various microorganisms into the aquaculture pond. The amount of organisms can be reduced accordingly (the sediment content in the buffer device can be measured and transmitted to the third controller via a turbidity meter); when the water retention time of the solid-liquid separation module is satisfied, the supernatant discharge pump in the solid-liquid separation module is turned on, and the supernatant is discharged into the denitrification unit (the first sand filter module of the denitrification unit) for denitrification treatment and then discharged back into the aquaculture pond. After the supernatant is discharged, the waste solid harmless treatment module is turned on through the third controller, and the waste solid is treated in combination with the utilization and destination of the waste solid. For example, when used as water fertilizer, it is directly diluted to reduce salinity. The treated waste solid is sent to the power plant for incineration through the waste solid transportation module for subsequent dehydration and other treatments.

[0137] In step 5, the content of residual feed and suspended matter in the aquaculture pond is obtained by the second sensor. When it is lower than the control threshold, the feeder is controlled by the fifth controller to remove feed from the feed bin and put it into the aquaculture pond to meet the needs of aquaculture in the pond.

[0138] In one feasible embodiment, monitoring the levels of growth elements required for aquatic products in a culture pond includes the following steps:

[0139] When the content of at least one of trace elements, bacterial flocs and carbon in the aquaculture pond is lower than the corresponding first set threshold, the corresponding modules are activated to add at least one of the trace elements, bacterial flocs and carbon sources configured in proportion to the aquaculture pond. The added trace elements, bacterial flocs and carbon sources enter the aquaculture pond together with the denitrified water.

[0140] It should be noted that the trace element content is obtained through a trace element analyzer, the content of bacterial flocs (heterotrophic microorganisms) is obtained through the plate method, and the carbon-nitrogen ratio is calculated after measuring the carbon and nitrogen content in the water. The trace element control module adds the prepared trace element solution to the aquaculture pond through a peristaltic pump. The heterotrophic microorganism control module usually contains freeze-dried heterotrophic microorganism powder, which is added to the aquaculture pond through a metering valve. The carbon-nitrogen ratio adjustment module delivers external carbon and nitrogen sources to the aquaculture pond through a peristaltic pump to maintain an optimal carbon-nitrogen ratio in the aquaculture environment.

[0141] Furthermore, after repeated filtration, the content of trace elements in the aquaculture pond water decreases, affecting the quality of aquatic products. The trace element control module adjusts the concentration of trace elements in the water environment and the ratio between various components to meet the needs of aquatic product growth. The heterotrophic microorganism control module adjusts the content of assimilating microorganisms in the aquaculture pond, so that the concentration of organic matter and ammonia nitrogen can be controlled more quickly, avoiding the accumulation of organic matter and ammonia nitrogen and improving the efficiency of water treatment. The carbon-nitrogen ratio adjustment module can control the number of a certain type of microorganism and the growth of algae. These control and regulation components enter the aquaculture pond through the water propulsion device and can diffuse rapidly, meeting the water requirements of aquatic product aquaculture.

[0142] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "a plurality" refers to two or more unless otherwise expressly defined.

[0143] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. The invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.

[0144] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A coupled recirculating aquaculture system, characterized in that, The coupled recirculating aquaculture system includes: Aquaculture pond for aquaculture, wherein the aquaculture pond is equipped with a central suspended solids drainage pipe and a water pushing device; The denitrification unit has its inlet connected to the central suspended solids drain pipe and its outlet connected to the water-pushing device. The denitrification unit is used to denitrify the water and then sends the denitrified water back to the aquaculture pond through the water-pushing device. The denitrification unit includes a nitrifying bacteria cultivation module and a water temperature and dissolved oxygen control module. The outlet of the water temperature and dissolved oxygen control module is connected to the water pushing device. The nitrifying bacteria cultivation module is used to perform biological denitrification on the filtered water and cultivate nitrifying bacteria. Then, the water rich in nitrifying bacteria is sent back to the aquaculture pond after passing through the water temperature and dissolved oxygen control module. A carbon-nitrogen ratio coordination unit is connected between the water-pushing device and the denitrification unit. The carbon-nitrogen ratio coordination unit adjusts the content of growth elements in the water entering the aquaculture pond in a timely manner according to the changes in the growth elements required by the aquatic products in the aquaculture pond. At the same time, the carbon-nitrogen ratio coordination unit, together with the water discharged from the denitrification unit, is sent into the aquaculture pond through the water-pushing device. The carbon-nitrogen ratio coordination unit includes a carbon-nitrogen ratio adjustment module, which is used to deliver external carbon and nitrogen sources to the aquaculture pond through a peristaltic pump, so that the aquaculture environment always maintains an optimal carbon-nitrogen ratio, thereby controlling the number of microorganisms and the growth of algae. The aquaculture pond is also equipped with a central bottom sewage pipe. The recirculating aquaculture system also includes a solid-liquid separation unit connected to the central bottom sewage pipe. Water passing through the solid-liquid separation unit enters the denitrification unit, and solid waste passing through the solid-liquid separation unit is discharged from the solid-liquid separation unit. The solid-liquid separation unit includes a buffer module connected to the central bottom drain pipe and the denitrification unit. The buffer module is used to receive the sediment water in the aquaculture pond and the waste liquid from the denitrification unit. A solid-liquid separation module, wherein the inlet of the solid-liquid separation module is connected to the buffer module, and the first outlet of the solid-liquid separation module is connected to the denitrification unit; By periodically lowering the water level in the buffer module, intermittent sewage discharge of sediment at the bottom of the aquaculture pond is achieved. When sewage is not being discharged, the water level in the buffer module remains the same as the water level in the aquaculture pond. The recirculating aquaculture system also includes a water supply unit for providing replenishment water to the aquaculture pond. The water supply unit is also connected to the solid-liquid separation unit to prevent excessive suspended solids and organic matter from entering the aquaculture pond. The water supply unit includes: A reservoir is used to store replenished water. A booster module, the inlet of which is connected to the outlet of the water storage tank; The second sand filter module has its inlet connected to the outlet of the pressurization module, its first outlet connected to the second disinfection and sterilization module, and its second outlet connected to the buffer module.

2. The coupled recirculating aquaculture system according to claim 1, characterized in that, The solid-liquid separation unit further includes: A solid waste treatment module, wherein the inlet of the solid waste treatment module is connected to the second outlet of the solid-liquid separation; The waste and solid waste transportation module is connected to the outlet of the waste and solid waste harmless treatment module; The third controller is connected to the buffer module, the solid-liquid separation module, the waste solid harmless treatment module, and the waste solid transportation module, respectively. The third controller controls the operation of the solid-liquid separation module, the waste solid harmless treatment module, and the waste solid transportation module according to the amount of sediment and the liquid level in the buffer module.

3. The coupled recirculating aquaculture system according to claim 1, characterized in that, The aquaculture pond is equipped with an automatic water replenishment device, and the water source replenishment unit is connected to the automatic water replenishment device.

4. The coupled recirculating aquaculture system according to claim 3, characterized in that, The water supply unit also includes: A pressure stabilization module, the inlet of which is connected to the outlet of the second disinfection and sterilization module, and the outlet of which is connected to the automatic water replenishment device; The fourth controller is connected to the pressure stabilization module, the pressurization module, the second sand filter module, and the second disinfection and sterilization module respectively. The fourth controller controls the operation of the pressurization module, the second sand filter module, and the second disinfection and sterilization module according to the pressure of the pressure stabilization module.

5. The coupled recirculating aquaculture system according to claim 2, characterized in that, The denitrification unit includes: a coarse particle filtration module, a fine particle and dissolved organic matter separation module, a first sand filter module, and a first disinfection and sterilization module connected in sequence. The inlet of the coarse particle filtration module is connected to the central suspended solids drain pipe via a water pump. The coarse particle filtration module, the fine particle and dissolved organic matter separation module, and the first sand filter module are also connected to the buffer module. The first sand filter module is also used to receive the water discharged from the solid-liquid separation module. The denitrification unit further includes a first controller, which is connected to the water pump, the coarse particle filtration module, the fine particle and dissolved organic matter separation module, the first sand filter module, the first disinfection and sterilization module, the nitrifying bacteria cultivation module, and the water temperature and dissolved oxygen control module. The first controller controls the operation of the water pump, the coarse particle filtration module, the fine particle and dissolved organic matter separation module, the first sand filter module, the first disinfection and sterilization module, the nitrifying bacteria cultivation module, and the water temperature and dissolved oxygen control module based on the data in the nitrifying bacteria cultivation module and the information in the water temperature and dissolved oxygen control module.

6. The coupled recirculating aquaculture system according to claim 5, characterized in that, The carbon-nitrogen ratio coordination unit further includes: a second controller, a trace element control module, and a heterotrophic microorganism control module. The second controller is also connected to a first sensor in the aquaculture pond. The second controller controls the operation of the trace element control module, the heterotrophic microorganism control module, and the carbon-nitrogen ratio adjustment module according to the trace element content, floc content, and ammonia nitrogen concentration in the aquaculture pond. The outlets of the trace element control module, the heterotrophic microorganism control module, and the carbon-nitrogen ratio adjustment module are connected to the Venturi tube at the outlet of the water temperature and dissolved oxygen control module, and after mixing with the water from the denitrification unit, they enter the aquaculture pond through the water-pushing device. The first sensor is used to acquire information on the content of trace elements, suspended solids, and ammonia nitrogen in the aquaculture pond.

7. The coupled recirculating aquaculture system according to claim 1, characterized in that, The recirculating aquaculture system also includes a feeding unit connected to the aquaculture pond, which provides feed to the aquaculture pond according to the content of residual feed and suspended solids in the pond. The fabric unit includes: Feed bins are used to store bait; A feeder, the inlet of which is connected to the outlet of the feed hopper, and the outlet of which is connected to the aquaculture pond; The fifth controller is connected to the second sensor in the aquaculture pond and the feeder respectively. The fifth controller controls the operation of the feeder according to the content of residual feed and suspended solids in the aquaculture pond, so as to put the feed in the feed bin into the aquaculture pond. The second sensor is used to acquire information on the content of residual feed and suspended matter in the aquaculture pond.

8. A method for recirculating aquaculture using the coupled recirculating aquaculture system according to any one of claims 1-7, characterized in that, The recirculating aquaculture system includes the following steps: Provide driving force for the water in the aquaculture pond; A portion of the water in the aquaculture pond is denitrified, and the denitrified water is then discharged back into the aquaculture pond. Monitor the content of growth elements required by aquatic products in the aquaculture pond. If the content of the growth elements is less than a first set threshold, supply the growth elements to the aquaculture pond. If the content of the growth elements is not less than the first set threshold, stop supplying the growth elements to the aquaculture pond. The sediment in the aquaculture pond is subjected to solid-liquid separation treatment. The supernatant is transported to the denitrification unit for denitrification treatment and then discharged back into the aquaculture pond, while the waste solids are discharged. The feed content in the aquaculture pond is monitored. When the feed content is less than a second set threshold, feed is supplied to the aquaculture pond. When the feed content is not less than the second set threshold, the supply of feed to the aquaculture pond is stopped.

9. The recirculating aquaculture method according to claim 8, characterized in that, Monitoring the levels of growth elements required by aquatic products in the aquaculture pond includes the following steps: When the content of at least one of trace elements, bacterial flocs and carbon in the aquaculture pond is lower than the corresponding first set threshold, the corresponding modules are activated to add at least one of the trace elements, bacterial flocs and carbon sources configured in proportion to the aquaculture pond. The added trace elements, bacterial flocs and carbon sources enter the aquaculture pond together with the denitrified water.

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