A double-ring concentric tank in-situ purification high-density aquaculture system

Abstract

The application discloses a double-ring concentric tank in-situ purification high-density aquaculture system, which comprises a double-layer tank main body divided into an inner ring culture bin and an outer ring biochemical bin by a ring-shaped isolation plate. A central rotational flow circulating pump is arranged at the center of the inner ring culture bin to drive synchronous rotational flow of water bodies in the double bins. A conical bottom sludge collecting slope is arranged at the bottom of the tank to collect residual feed and fish manure, which is introduced into an external sedimentation tank by gravity flow through a bottom flow sewage pipe. After sedimentation, the supernatant is pumped into the outer ring biochemical bin by a supernatant lifting pump and is subjected to biochemical degradation by an MABR aeration membrane biochemical unit. After purification, the water bodies are unidirectionally returned to the inner ring culture bin through a molecular sieve permeation flow guide structure embedded on the ring-shaped isolation plate. The system is integrated with ultraviolet disinfection and online spectrum water quality monitoring modules, and the operation parameters are automatically regulated and controlled by a PLC. The system integrates the functions of culture, sludge collection, sedimentation, biochemical purification and disinfection, has few power equipment, low energy consumption, small land occupation and is suitable for high-density industrial aquaculture.

Description

Technical Field

[0001] This invention relates to the field of aquaculture system technology, specifically to a high-density aquaculture system with in-situ purification using a double-ring concentric tank. Background Technology

[0002] High-density recirculating aquaculture systems typically employ a separate arrangement of aquaculture ponds and water treatment equipment. The aquaculture ponds are constructed independently from water treatment units such as biological filtration tanks and sedimentation tanks, connected via pipelines and circulating water pumps. This system model requires a large footprint, involves lengthy piping, and demands high pump head, resulting in high energy consumption. While traditional concentric aquaculture tanks coaxially arrange the aquaculture area and filter media area to save space, they rely solely on simple physical filtration separation and lack independent membrane bioreactor biochemical degradation units. This leads to low removal efficiency for key indicators such as dissolved ammonia nitrogen and nitrite, making stable water quality control difficult.

[0003] Conventional aquaculture tanks typically feature flat or slightly sloping bottoms, leading to poor settling of fish feces and uneaten feed. This results in a persistent presence of suspended organic matter in the water, causing rapid water quality deterioration and high dissolved oxygen consumption, making it unsuitable for fry rearing and ultra-high-density adult fish farming. Furthermore, existing circulating water systems rely entirely on externally mounted multiple pumps for forced circulation, requiring separate power units such as aquaculture circulation pumps, biological return pumps, and sewage pumps. This results in a complex system with numerous pipe interfaces, high maintenance costs, and multiple potential points of failure. Moreover, it lacks a bidirectional, dynamically balanced, self-circulating water flow structure between the internal and external areas of the tank.

[0004] In summary, current recirculating aquaculture technology has significant shortcomings in terms of equipment integration, in-situ biochemical treatment capacity, solid-liquid separation efficiency, and water circulation energy consumption control. There is an urgent need for an innovative device that can integrate aquaculture, waste collection, sedimentation, membrane biochemical treatment, and self-circulating water flow. Summary of the Invention

[0005] To address the shortcomings of existing recirculating aquaculture systems, such as low integration, numerous dead zones in water circulation, poor waste collection, high energy consumption, and unstable water quality, this invention provides a high-density aquaculture system with in-situ purification in a double-ring concentric tank.

[0006] The technical solution adopted in this invention is as follows: A high-density aquaculture system with in-situ purification in a double-ring concentric tank, comprising: a double-layer tank body, including an inner ring aquaculture chamber and an outer ring biochemical chamber separated by an annular partition plate; a central vortex circulation pump, located in the central area of ​​the inner ring aquaculture chamber, for driving the water in the inner ring aquaculture chamber and the outer ring biochemical chamber to vortex synchronously; a cone-bottom sludge collection structure, located at the bottom center of the double-layer tank body, for collecting uneaten feed and fish feces generated during aquaculture; an external sedimentation tank, connected to the cone-bottom sludge collection structure through a bottom flow sewage pipe; a supernatant lift pump, for transporting the supernatant separated from the external sedimentation tank to the outer ring biochemical chamber; a MABR aeration membrane biochemical unit, located in the outer ring biochemical chamber, for biochemical degradation and purification of the water; and a molecular sieve permeation guiding structure, embedded in the annular partition plate, for allowing the purified water in the outer ring biochemical chamber to flow unidirectionally back to the inner ring aquaculture chamber.

[0007] Preferably, the conical bottom sludge collection structure is a conical bottom sludge collection slope set at the bottom of the double-walled tank body, the slope of the conical bottom sludge collection slope is 10° to 15°, and the bottom flow discharge pipe is connected to the lowest point of the center of the conical bottom sludge collection slope.

[0008] Preferably, a central diversion tank is vertically arranged in the central area of ​​the inner ring aquaculture tank, and the wall of the central diversion tank is provided with water permeable holes.

[0009] Preferably, the central vortex circulation pump draws water upwards and discharges water horizontally in both directions, thereby simultaneously driving the water in the inner ring aquaculture tank and the outer ring biochemical tank to form a circumferential vortex; the central vortex circulation pump is equipped with a protective basket on its exterior.

[0010] Preferably, the external sedimentation tank is a vertical cone-bottom sedimentation tank, with an installation elevation lower than the main body of the double-layer tank. The bottom flow sewage pipe relies on the liquid level difference to achieve gravity flow of wastewater. The upper part of the sedimentation tank is connected to a clear water cylinder through a pipeline, and the inlet end of the supernatant lift pump is connected to the clear water cylinder.

[0011] Preferably, the bottom of the outer ring biochemical chamber is provided with a microporous aeration pipe to supply oxygen to the MABR aeration membrane biochemical unit and continuously sweep the membrane in a bubble-free aeration manner.

[0012] Preferably, the outer ring biochemical chamber is equipped with an online spectral water quality monitoring module, which integrates an ultraviolet-visible spectral probe and a dissolved oxygen probe.

[0013] Preferably, it also includes a PLC control system, which is signal-connected to the online spectral water quality monitoring module, the central vortex circulation pump, and the supernatant lift pump, and is used to automatically adjust the operating flow rate of the central vortex circulation pump and the supernatant lift pump and the aeration rate of the microporous aeration pipe according to the monitoring data of the online spectral water quality monitoring module.

[0014] Preferably, the inner ring aquaculture chamber is equipped with an immersion ultraviolet disinfection module.

[0015] Preferably, the body of the double-walled tank is circular, square, rectangular, or irregular in shape, and is integrally molded from PP, carbon steel (corrosion resistant), or stainless steel.

[0016] The present invention has the following beneficial effects: 1. Water Circulation and Waste Collection: The central vortex circulation pump adopts an upward suction and horizontal bidirectional tangential discharge arrangement, which can simultaneously drive the water in the inner ring aquaculture tank and the outer ring biochemical tank to form an overall circumferential vortex. The water in the entire tank is kept in a state of live water circulation with minimal stagnant areas. The centrifugal force generated by the water vortex continuously pushes suspended waste towards the center of the tank. Combined with the guiding effect of the cone-shaped waste collection slope, uneaten feed and fish feces can be quickly settled and collected in the cone-shaped waste collection structure at the bottom center, and discharged through the bottom flow drain pipe, achieving effective separation of waste from the water.

[0017] 2. Equipment Energy Consumption: The entire unit is equipped with only two power units: a central vortex circulation pump and a supernatant lift pump. High-concentration wastewater collected by the cone-bottom collection structure flows by gravity into the sedimentation tank via the bottom discharge pipe, relying on the elevation difference between the double-walled tank and the external sedimentation tank, eliminating the need for an additional discharge pump. Water purified in the outer ring biological chamber flows unidirectionally back to the inner ring aquaculture chamber via the molecular sieve permeation guide structure, relying on the pressure difference between the inner and outer rings, eliminating the need for a biological return pump. Compared to traditional recirculating aquaculture systems that require multiple power units such as aquaculture circulation pumps, biological return pumps, and discharge pumps, this system has fewer power units and a shorter water circulation path, which helps reduce operating energy consumption.

[0018] 3. Equipment footprint: The double-walled tank integrates the inner ring breeding tank and the outer ring biochemical tank coaxially into the same tank body. The functions of breeding, sludge collection, sedimentation, biochemical purification and sterilization are integrated into one unit. There is no need to build multiple water treatment units such as breeding ponds, biochemical filtration ponds, and sedimentation ponds separately, nor is it necessary to lay a large number of external connecting pipelines. The overall footprint of the equipment is small.

[0019] 4. Operation and Maintenance: The gravity settling of the cone-bottom sludge collection structure and the slow-flow depth settling of the external sedimentation tank form a multi-stage solid-liquid separation path, maintaining the turbidity of the water entering the outer ring biochemical tank at a low level. The molecular sieve permeation guiding structure embedded in the annular isolation plate can prevent large particles of sludge from entering the outer ring biochemical tank. The microporous aeration pipes at the bottom of the outer ring biochemical tank continuously generate airflow sweeping action on the surface of the MABR aeration membrane during oxygen supply, which helps control the biofilm thickness. The above design helps delay membrane fouling and extend the cleaning cycle of the membrane module.

[0020] 5. Water Quality Control: An immersion-type ultraviolet disinfection module is installed in the inner ring aquaculture tank to irradiate the circulating water with ultraviolet light in situ, killing pathogens and parasite eggs in the water. An online spectral water quality monitoring module collects real-time parameters of ammonia nitrogen, nitrite, COD, and dissolved oxygen in the water. The PLC control system automatically adjusts the operating flow rate of the central vortex circulation pump and the supernatant lift pump, as well as the aeration rate of the microporous aeration pipes, based on the monitoring data, and in conjunction with the automatic sludge removal program, maintains the system's water quality indicators within the set range. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the equipment piping structure according to an embodiment of the present invention.

[0022] Figure 2 This is a top view schematic diagram of an embodiment of the present invention.

[0023] In the picture: 1-Inner ring aquaculture silo; 2-Outer ring biochemical chamber; 3- Annular isolation plate; 4-Molecular sieve permeation and flow guiding structure; 5-Center vortex circulation pump; 6-External sedimentation tank; 7-MABR aerated membrane biochemical unit; 8-Conical bottom sewage collection slope; 9-Online Spectral Water Quality Monitoring Module; 10-Bottom flow sewage pipe; 11-Supernatant lift pump; 12-Immersion UV disinfection module; 13-Central diversion tank; 14-Protective basket; 15 - Water container. Detailed Implementation

[0024] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0025] Overall structure: like Figure 1 and Figure 2As shown, the dual-ring concentric tank in-situ purification high-density aquaculture system provided in this embodiment mainly comprises: an inner ring aquaculture tank 1, an outer ring biochemical tank 2, an annular isolation plate 3, a molecular sieve permeation guiding structure 4, a central vortex circulation pump 5, an external sedimentation tank 6, a MABR aeration membrane biochemical unit 7, a cone-shaped bottom sludge collection slope 8, an online spectral water quality monitoring module 9, a bottom flow sewage pipe 10, a supernatant lift pump 11, an immersion ultraviolet disinfection module 12, a central guiding tank 13, a protective basket 14, and a clear water cylinder 15.

[0026] like Figure 1 and Figure 2 As shown, the double-layer tank adopts an inner and outer coaxial nested layout, with an annular partition plate 3 dividing the tank into an inner ring aquaculture chamber 1 and an outer ring biochemical chamber 2. The inner ring aquaculture chamber 1 is used for high-density aquaculture, while the outer ring biochemical chamber 2 houses the MABR aeration membrane biochemical unit 7. A central vortex circulation pump 5 is installed in the central area of ​​the inner ring aquaculture chamber 1, with its outlet direction arranged horizontally and tangentially. During operation, it simultaneously forms a unidirectional circumferential vortex in both the inner ring aquaculture chamber 1 and the outer ring biochemical chamber 2, keeping the water in the entire tank in a flowing state. A cone-shaped bottom sludge collection structure is set at the center of the bottom of the inner ring aquaculture chamber 1 to collect uneaten feed and fish feces. One end of the bottom discharge pipe 10 is connected to the lowest point of the cone-shaped bottom sludge collection structure, and the other end is connected to the external sedimentation tank 6. The inlet of the supernatant lift pump 11 is connected to the supernatant outlet pipe of the external sedimentation tank 6, and the outlet is connected to the upper part of the outer ring biochemical chamber 2. A detachable molecular sieve permeation guiding structure 4 is embedded circumferentially in the annular isolation partition 3, allowing the purified water in the outer ring biochemical chamber 2 to flow unidirectionally back to the inner ring aquaculture chamber 1. The molecular sieve permeation guiding structure 4 is an annular cylindrical embedded body, evenly distributed along the circumference of the annular isolation partition 3. The main body is made of stainless steel filter screen with a mesh size of 100-1000 mesh. The molecular sieve permeation guiding structure 4 is fixed to the pre-reserved installation window in the annular isolation partition 3 by a slot-type detachable connection, which can be replaced modularly and independently. Maintenance work does not require stopping the machine to disassemble the entire annular isolation partition. The above components work together to form a complete aquaculture-purification circulating water circuit.

[0027] like Figure 1 As shown, the cone-bottom sludge collection structure specifically consists of a cone-bottom sludge collection slope 8 located at the bottom of the double-walled tank body, with a slope ranging from 10° to 15°. The inlet of the bottom flow drain pipe 10 is connected to the lowest point of the cone-bottom sludge collection slope 8. This slope allows sludge to slide along the slope under the influence of gravity, and, combined with the centrifugal force generated by the swirling water, pushes the sludge towards the lowest point, thus improving the sludge collection efficiency. In actual operation, this slope can be adjusted according to the tank diameter and the species being farmed; a smaller slope value can be used for tanks with larger diameters, and a larger slope value can be used for tanks with smaller diameters.

[0028] like Figure 1 and Figure 2As shown, a central guide tank 13 is vertically installed in the central area of ​​the inner ring aquaculture tank 1. This guide tank has a cylindrical structure with evenly spaced perforations on its walls. The diameter of the perforations is smaller than the minimum size of the farmed fish and shrimp, preventing them from entering the central waste collection area while allowing the aquaculture water and small particles of waste to pass through freely. The central guide tank 13 isolates the aquaculture area from the waste collection area at the bottom center of the tank. Fish and shrimp are kept outside the guide tank, while waste can settle down to the bottom conical waste collection slope 8 with the water flow through the perforations. A central vortex circulation pump 5 is located beside the central guide tank 13; the two are independent components. The diameter of the perforations can be selected according to the specifications of the farmed species, and different diameter central guide tanks can be used for farmed species at different growth stages.

[0029] like Figure 1 As shown, the central vortex circulation pump 5 is vertically arranged with its suction port facing upwards, drawing water from the upper middle part of the inner ring aquaculture chamber 1, and its outlet is set horizontally. When the central vortex circulation pump 5 is running, it generates four tangential thrust flows in the horizontal direction. Two of these flow flows act on the inner ring aquaculture chamber 1, and two act on the outer ring biochemical chamber 2, synchronously driving the water in both chambers to form a unidirectional circulatory vortex, achieving full-tank live water circulation with minimal stagnant areas. The symmetrical arrangement of the two-way outlet thrust flows counteracts the radial imbalance force generated by the pump's operation, contributing to stable pump operation. The central vortex circulation pump 5 is externally equipped with a protective basket 14. This cage-like structure is installed around the pump body to prevent farmed fish and shrimp from approaching the pump and to intercept large suspended solids in the water, preventing them from entangled or clogging the pump's suction port. The grid spacing of the protective basket 14 can be selected according to the specifications of the farmed species.

[0030] like Figure 1 As shown, the external sedimentation tank 6 adopts a vertical conical bottom structure, and its overall installation elevation is lower than the bottom elevation of the double-walled tank body. The bottom flow discharge pipe 10 is led out from the lowest point of the center of the conical bottom sludge collection slope 8, and extends downwards to the liquid inlet of the external sedimentation tank 6. The wastewater is gravity-fed by relying on the liquid level difference, eliminating the need to install a sewage pump on the pipeline. The high-concentration wastewater entering the sedimentation tank rises slowly in the tank, and the solid particles settle to the bottom area under gravity, and can be discharged periodically through the sludge discharge port at the bottom of the conical bottom. The upper part of the sedimentation tank 6 is connected to the clear water cylinder 15 through a pipeline. The clarified supernatant after sedimentation and separation is led out from the upper part of the sedimentation tank 6 and flows into the clear water cylinder 15 for temporary storage. The inlet of the supernatant lift pump 11 is connected to the inside of the clear water cylinder 15, and the supernatant is drawn from the clear water cylinder 15 and transported to the outer ring biochemical chamber 2. The clear water tank 15 can keep the inlet water quality of the supernatant lift pump 11 stable, and avoid the suction of suspended solids due to liquid level fluctuations or water flow disturbances in the sedimentation tank 6.

[0031] The bottom of the outer ring biochemical chamber 2 is equipped with microporous aeration pipes, which are connected to an external air supply system. During operation, the microporous aeration pipes supply oxygen to the MABR aerated membrane biochemical unit 7 using a bubble-free aeration method. Oxygen diffuses through the MABR membrane surface to the biofilm layer, providing oxygen for use by aerobic microorganisms such as nitrifying bacteria attached to the membrane surface. Simultaneously, the rising airflow generated by the microporous aeration pipes continuously sweeps across the MABR membrane surface, creating a certain scouring effect, which helps control the biofilm thickness and prevents clogging due to excessive biofilm thickening. The bubble-free aeration method produces small air bubbles with high gas utilization, generating minimal disturbance in the water and avoiding stress on farmed fish and shrimp. The air supply from the microporous aeration pipes can be adjusted according to the dissolved oxygen concentration and water quality load.

[0032] like Figure 1 and Figure 2 As shown, an online spectral water quality monitoring module 9 is installed on the effluent side of the outer ring biochemical chamber 2. This module integrates an ultraviolet-visible spectral probe and a dissolved oxygen probe. The ultraviolet-visible spectral probe emits ultraviolet-visible light into the water and collects absorbance signals. By analyzing the absorbance changes at different wavelengths, the concentrations of ammonia nitrogen, nitrite, and COD in the water can be calculated. This operation requires no chemical reagents and can run continuously online. The dissolved oxygen probe measures the dissolved oxygen content in the water in real time. This monitoring module can continuously acquire the changing trends of water quality parameters, providing real-time data input for system control.

[0033] The PLC control system establishes signal connections with the online spectral water quality monitoring module 9, the central vortex circulation pump 5, and the supernatant lift pump 11. The online spectral water quality monitoring module 9 transmits the collected ammonia nitrogen, nitrite, COD, and dissolved oxygen parameters to the PLC control system. The PLC control system performs judgments and calculations based on the set values. When a parameter deviates from the set range, the system automatically outputs adjustment signals: adjusting the operating flow rate of the central vortex circulation pump 5 to change the water circulation intensity, adjusting the operating flow rate of the supernatant lift pump 11 to control the water load entering the outer ring biochemical chamber 2, and adjusting the air supply of the microporous aeration pipe to change the oxygen supply intensity. The system also has an automatic sludge discharge program, automatically opening the sludge discharge valve based on the operating time or the degree of sludge accumulation at the bottom of the sedimentation tank. The entire system can achieve continuous operation with minimal manual intervention under PLC control.

[0034] like Figure 1 and Figure 2As shown, the immersion-type ultraviolet disinfection module 12 is fixedly installed below the water surface in the inner ring aquaculture tank 1, typically arranged around the central vortex circulation pump 5. The swirling water flow repeatedly passes over the surface of the ultraviolet lamp tube, allowing it to be irradiated by ultraviolet light. Ultraviolet light can destroy the DNA structure of pathogens and parasite eggs in the water, rendering them inactive and achieving disinfection. This module can be directly installed inside the tank, eliminating the need for separate disinfection equipment on external pipelines, thus reducing pipe joints and sealing points.

[0035] The shape of the double-walled tank can be selected from circular, square, rectangular, or irregular structures according to site conditions and operational requirements. Circular tanks facilitate uniform swirling distribution, while square or rectangular tanks allow for the side-by-side arrangement of multiple units, saving space. The tank material can be PP plastic, corrosion-resistant carbon steel, or stainless steel. PP is suitable for freshwater aquaculture and is relatively inexpensive, while stainless steel is suitable for seawater aquaculture or applications requiring high corrosion resistance. Corrosion-resistant carbon steel is suitable for manufacturing large-scale tanks. All of these materials can be processed using a one-piece molding process, resulting in a high overall structural strength and fewer welds, which helps reduce the risk of leakage.

[0036] Working principle: Before the system is put into operation, add aquaculture water to the inner ring aquaculture tank 1 and the outer ring biochemical tank 2 to the working water level to ensure that the water levels inside and outside are balanced; add nitrifying bacteria agent to the outer ring biochemical tank 2, and aerate it with the MABR aeration membrane for 5 to 7 days to complete the biofilm attachment and acclimatization, and build a stable biochemical treatment microbial community system.

[0037] After domestication, the fish can be introduced for breeding, and the central vortex circulation pump 5, the supernatant lift pump 11, and the immersion ultraviolet disinfection module 12 are started simultaneously. The central vortex circulation pump 5 drives the inner ring breeding tank 1 and the outer ring biochemical tank 2 to form a full-area circular vortex through four tangential push flow, realizing the circulation of live water throughout the tank. Fish feces, uneaten feed, and suspended waste generated during breeding are collected towards the center of the tank under the action of centrifugal force and gravity at the bottom of the cone. They settle through the water permeable holes of the central guide tank 13 to the lowest point of the bottom cone bottom sludge collection slope 8, forming high-concentration wastewater.

[0038] High-concentration wastewater flows into the external sedimentation tank 6 by gravity through the bottom flow sewage pipe 10, relying on the liquid level difference. After the water flows slowly, solid-liquid separation is achieved. The sludge settles to the bottom of the cone and is automatically discharged periodically. The clarified supernatant flows into the clear water cylinder 15 through the pipeline and is quantitatively transported to the outer ring biochemical chamber 2 for deep purification by the supernatant lift pump 11.

[0039] The supernatant flows through the MABR aeration membrane biochemical unit 7 area of ​​the outer ring biochemical chamber 2. The biofilm attached to the membrane surface degrades ammonia nitrogen, nitrite and organic pollutants in the water. The matching microporous aeration pipe continuously supplies oxygen and washes the membrane surface, controls the biofilm thickness and prevents membrane blockage.

[0040] After being deeply purified by the outer ring biochemical chamber 2, the water flows back to the inner ring aquaculture chamber 1 through the molecular sieve permeation guiding structure 4 under the action of the water level difference between the inner and outer rings, forming a continuous closed-loop self-circulating purification water path.

[0041] During system operation, the online spectral water quality monitoring module 9 monitors the parameters of ammonia nitrogen, nitrite, COD and dissolved oxygen in the water in real time and feeds them back to the PLC control system. The system intelligently links and adjusts the operating flow rate of the central vortex circulation pump 5 and the supernatant lift pump 11 as well as the aeration volume of the microporous aeration pipe. Combined with the automatic sludge discharge and in-situ ultraviolet sterilization functions, the system can achieve continuous automatic operation.

[0042] Example 1. High-density fry rearing device: The double-walled tank adopts a concentric circular structure with a total diameter of 3m. The inner ring aquaculture chamber 1 has a diameter of 2m, the outer ring biochemical chamber 2 has an annular width of 0.5m, and the total height of the tank is 1.4m. The slope of the conical bottom sludge collection slope 8 is set at 15°. The rated flow rate of the central vortex circulation pump 5 is 5m³ / h, the effective volume of the external sedimentation tank 6 is 0.8m³, and the effective volume of the clear water cylinder 15 is 0.3m³. Four sets of flat-plate MABR aeration membrane modules are evenly arranged in the outer ring biochemical chamber 2, and the air supply of the microporous aeration pipe is 1m³ / h. The molecular sieve permeation guiding structure 4 embedded in the annular isolation plate 3 has a pore size of 0.5mm.

[0043] Before system operation, aquaculture water is added to the inner ring aquaculture tank 1 and the outer ring biochemical tank 2 to the working water level. Nitrifying bacteria are added to the outer ring biochemical tank 2, and the microporous aeration pipe is turned on for 5 to 7 days of acclimation. After a stable biofilm forms on the MABR membrane surface, acclimation is complete. After acclimation, fry are released, with a single release of 200,000 fry. The central vortex circulation pump 5, the supernatant lift pump 11, and the immersion ultraviolet disinfection module 12 are started, and the system runs continuously. During the aquaculture period, the online spectral water quality monitoring module 9 shows that the nitrite concentration in the water remains stable below 0.03 mg / L. Compared with traditional split-type recirculating aquaculture equipment, the system energy consumption of this embodiment is reduced by 38%.

[0044] Example 2. Containerized complete set of equipment for adult fish farming: The system utilizes a 40HQ standard shipping container as its carrier, with two concentric double-ring aquaculture tanks integrated inside. Each tank has an effective aquaculture water volume of 8 m³, and the slope of the conical bottom sludge collection slope 8 is set at 12°. The system is equipped with an online spectral water quality monitoring module 9 for real-time monitoring of ammonia nitrogen, nitrite, COD, and dissolved oxygen. The PLC control system automatically adjusts the operating flow rates of the central vortex circulation pump 5, the supernatant lift pump 11, and the air supply of the microporous aeration pipes based on the monitoring data.

[0045] This embodiment is applicable to high-density recirculating aquaculture systems for species such as yellow catfish, freshwater grouper, and forage fish. During system operation, the PLC control system executes an automatic sludge discharge program every 24 hours, opening the cone-bottom sludge discharge valve of the external sedimentation tank 6 to discharge concentrated sludge. Under the above operating conditions, the membrane module cleaning cycle of the MABR aeration membrane biochemical unit 7 is approximately 60 days.

[0046] Obviously, the above embodiments of the present invention are merely illustrative examples to illustrate the invention and are not intended to limit the implementation of the invention. Other obvious variations or modifications derived from the essential spirit of the invention still fall within the protection scope of the invention.

Claims

1. A high-density aquaculture system with in-situ purification using a double-ring concentric tank, characterized in that, include: The double-walled tank body includes an inner ring aquaculture chamber (1) and an outer ring biochemical chamber (2) separated by an annular partition plate (3); A central vortex circulation pump (5) is set in the central area of ​​the inner ring aquaculture tank (1) to drive the water in the inner ring aquaculture tank (1) and the outer ring biochemical tank (2) to vortex synchronously. A cone-shaped bottom sludge collection structure is located at the bottom center of the double-walled tank body to collect uneaten feed and fish feces generated during aquaculture. An external sedimentation tank (6) is connected to the cone-bottom sludge collection structure via an underflow sewage pipe (10); A supernatant booster pump (11) is used to transport the supernatant separated from the external sedimentation tank (6) to the outer ring biochemical chamber (2). The MABR aerated membrane biochemical unit (7) is set inside the outer ring biochemical chamber (2) and is used to biochemically degrade and purify the water. A molecular sieve permeation guiding structure (4) is embedded in the annular isolation plate (3) to allow the water purified by the outer ring biochemical chamber (2) to flow back to the inner ring aquaculture chamber (1) in one direction.

2. The in-situ purification high-density aquaculture system with double-ring concentric tanks according to claim 1, characterized in that, The conical bottom sludge collection structure is a conical bottom sludge collection slope (8) set at the bottom of the double-layer tank body. The slope of the conical bottom sludge collection slope (8) is 10° to 15°. The bottom flow sewage pipe (10) is connected to the lowest point of the center of the conical bottom sludge collection slope (8).

3. The in-situ purification high-density aquaculture system with double-ring concentric tanks according to claim 1, characterized in that, The inner ring aquaculture tank (1) is vertically arranged in the central area, and the wall of the central flow tank (13) is provided with water permeable holes.

4. The in-situ purification high-density aquaculture system with double-ring concentric tanks according to claim 1, characterized in that, The central vortex circulation pump (5) draws water upwards and discharges water horizontally in both directions, which is used to simultaneously drive the water in the inner ring aquaculture tank (1) and the outer ring biochemical tank (2) to form a circumferential vortex; the central vortex circulation pump (5) is equipped with a protective basket (14) on the outside.

5. The in-situ purification high-density aquaculture system with double-ring concentric tanks according to claim 1, characterized in that, The external sedimentation tank (6) is a vertical cone-bottom sedimentation tank, and its installation elevation is lower than that of the double-layer tank body. The bottom flow sewage pipe (10) relies on the liquid level difference to achieve gravity flow of sewage. The upper part of the sedimentation tank (6) is connected to a clear water cylinder (15) through a pipeline, and the inlet end of the supernatant lifting pump (11) is connected to the clear water cylinder (15).

6. The in-situ purification high-density aquaculture system with double-ring concentric tanks according to claim 1, characterized in that, The bottom of the outer ring biochemical chamber (2) is provided with a microporous aeration pipe, which supplies oxygen to the MABR aeration membrane biochemical unit (7) in a bubble-free aeration manner and continuously sweeps the membrane.

7. The in-situ purification high-density aquaculture system with double-ring concentric tanks according to claim 6, characterized in that, The outer ring biochemical chamber (2) is equipped with an online spectral water quality monitoring module (9), which integrates an ultraviolet-visible spectral probe and a dissolved oxygen probe.

8. The in-situ purification high-density aquaculture system with double-ring concentric tanks according to claim 7, characterized in that, It also includes a PLC control system, which is connected to the online spectral water quality monitoring module (9), the central vortex circulation pump (5), and the supernatant lift pump (11) by signal connection. The PLC control system is used to automatically adjust the operating flow rate of the central vortex circulation pump (5) and the supernatant lift pump (11) and the aeration volume of the microporous aeration pipe according to the monitoring data of the online spectral water quality monitoring module (9).

9. The in-situ purification high-density aquaculture system using a double-ring concentric tank as described in claim 1, characterized in that, The inner ring aquaculture chamber (1) is equipped with an immersion ultraviolet disinfection module (12).

10. The in-situ purification high-density aquaculture system using a double-ring concentric tank according to claim 1, characterized in that, The double-walled tank body is round, square, rectangular or irregular in shape, and is integrally molded from PP, carbon steel anti-corrosion or stainless steel.

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