A culture tail water treatment circulation system and method

Abstract

This invention discloses a wastewater treatment and recycling system for aquaculture, comprising a land-based circular pool connected to the input end of a sewage pipe, the output end of which is located above a solid collection assembly. The solid collection assembly is housed within an inlet pool. The upper half of the inlet pool is connected to the lower end of an overflow pipe, and the upper end of the overflow pipe is connected to the upper half of the land-based circular pool. The inlet pool is sequentially connected to a collection well, a solid-liquid separation mechanism, and a sedimentation tank via a drainage pipe. The sedimentation tank is connected to an existing pond via an artificial wetland. The existing pond is connected to the input end of the inlet pipe via a return water pool. The output end of the inlet pipe is connected to the land-based circular pool. This invention effectively reduces equipment downtime, lowers water intake costs and water resource consumption-related expenses in aquaculture production, avoids pollution to the surrounding water environment caused by direct wastewater discharge, improves wastewater collection efficiency, and reduces the labor intensity of equipment maintenance.

Description

Technical Field

[0001] This invention relates to a water treatment and recycling system, and more particularly, to a land-based circular pond aquaculture wastewater treatment and recycling system. Background Technology

[0002] Aquaculture is a production activity that involves the artificial cultivation and reproduction of plants and animals. Currently, the aquaculture industry cannot meet both actual production needs and environmental protection requirements, specifically including the following points: 1. The bottom of most existing aquaculture ponds adopts a single gentle slope design, which makes it difficult for solid pollutants such as uneaten feed and feces generated during the breeding process to quickly collect at the sewage outlet. They tend to stagnate and accumulate at the bottom of the pond, which not only breeds harmful microorganisms but also reduces sewage collection efficiency. At the same time, the pipes connecting the aquaculture ponds to the subsequent treatment units lack targeted filtration and anti-clogging designs. Large impurities such as uneaten feed clumps and aquatic organism remains can easily enter the pipes directly, frequently causing blockage problems. This requires shutdown for cleaning, which seriously affects the continuity of the treatment process and increases the maintenance costs and labor intensity of aquaculture production. 2. The existing system lacks an effective water quality and quantity regulation unit. High-concentration pollutants are prone to enter the core treatment modules such as solid-liquid separation and filtration, which not only exceeds the module's processing capacity, causing the separation holes to become clogged and the filtration accuracy to decrease, but also damages the stability of the microbial community in the treatment unit, reduces the degradation efficiency of pollutants such as organic matter, nitrogen and phosphorus, and ultimately affects the quality of the effluent. 3. Most existing treatment systems treat aquaculture wastewater through simple primary filtration or sedimentation. On the one hand, they fail to effectively remove residual fine suspended particles (such as microbial flocs and tiny solid fragments) from the water, resulting in high turbidity. Direct reuse of this water can negatively impact the growth environment of aquaculture organisms. On the other hand, they do not completely degrade key pollutants such as organic matter, nitrogen, and phosphorus. Discharge of these pollutants can easily cause eutrophication of surrounding water bodies, leading to ecological problems such as red tides and algal blooms, which does not meet environmental discharge standards. To meet reuse requirements, new water treatment processes need to be introduced, increasing equipment investment and operating costs. 4. In aquaculture areas where water resources are scarce or water access is inconvenient, existing aquaculture cannot achieve efficient recycling of wastewater and still requires a large amount of fresh water to maintain aquaculture production, which greatly increases water access costs. At the same time, solid waste such as uneaten feed and feces separated during the treatment process are mostly discarded directly without being utilized as resources, resulting in resource waste.

[0003] Therefore, those skilled in the art are dedicated to providing a system and method for treating and recycling aquaculture wastewater that can effectively solve the above-mentioned technical problems. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides an aquaculture wastewater treatment and recycling system, comprising a land-based circular pool connected to the input end of a sewage pipe, the output end of which is located above a solid collection component, the solid collection component being disposed within an inlet pool, the upper half of which is connected to the lower end of an overflow pipe, and the upper end of the overflow pipe being connected to the upper half of the land-based circular pool; the inlet pool is sequentially connected to a collection well, a solid-liquid separation mechanism, and a sedimentation tank via a drainage pipe, the sedimentation tank being connected to an existing pond via an artificial wetland, the existing pond being connected to the input end of the inlet pipe via a return water pool, and the output end of the inlet pipe being connected to the land-based circular pool.

[0005] Furthermore, the bottom of the land-based circular pool includes a first slope section and a second slope section from the outside to the inside. The slope of the first slope section is 4.5%-5.5%, and the slope of the second slope section is 19%-21%. A planar positioning area is provided at the bottom end of the second slope section, and the inlet of the sewage pipe is located at the upper center of the planar positioning area. A grid is provided inside the land-based circular pool, and the edge of the grid is located at the connection between the first slope section and the second slope section. A water quality monitoring sensor is provided inside the land-based circular pool to monitor key indicators such as dissolved oxygen, pH value, and ammonia nitrogen concentration in real time. When the monitoring data exceeds the standard range for aquaculture water, an early warning device is automatically triggered. The artificial wetland includes a first artificial wetland, a second artificial wetland, a third artificial wetland, and a fourth artificial wetland connected in sequence.

[0006] Furthermore, a sewage pump is installed on the sewage pipe, and the sewage pipe includes a positioning section. The input end of the positioning section is located at the upper end of the planar positioning area, and the output end of the positioning section is connected to the front end of the extension section. The rear end of the extension section is located in the water inlet pool and is connected to the input end of the sewage discharge section. The output end of the sewage discharge section is located above the water inlet pool. The extension section is inclined in a way that is higher at the front and lower at the back.

[0007] Furthermore, the upper half of the inlet pool is provided with a protrusion, and a stainless steel mesh cover is provided at the protrusion. The solid collection component is located below the stainless steel mesh cover. The solid collection component includes a collection frame, which is supported by support bars, each of which is located on the inner wall of the inlet pool. Two solid-liquid filter plates are symmetrically arranged inside the collection frame. Each solid-liquid filter plate is inclined with the outer side higher than the inner side. Each solid-liquid filter plate has several elongated filter holes. A fixing plate is provided at the lower inner side of each solid-liquid filter plate. The fixing plates are connected by a guide plate. The guide plate is inclined, and its lower end is the output end for discharging solids. Several connecting pipes connected to the inner wall of the collection frame are provided on the upper outer side of each solid-liquid filter plate. Each connecting pipe extends along the length of the collection frame and is provided with a cleaning nozzle. Each cleaning nozzle is inclined, and its center line is in the same direction of inclination as the solid-liquid filter plate. The bottom end of the guide plate is located at the collection port of the collection frame.

[0008] Further, the solid-liquid separation mechanism includes a solid-liquid separation platform, on which a solid-liquid separation cylinder is rotatably mounted. The solid-liquid separation cylinder has several solid-liquid separation holes for discharging liquid. The solid-liquid separation platform has a liquid storage chamber communicating with the solid-liquid separation holes. A water outlet pipe is provided in the lower half of the solid-liquid separation platform, penetrating the liquid storage chamber, and a valve is provided on the water outlet pipe. A power unit for driving the solid-liquid separation cylinder to rotate is located on the solid-liquid separation platform. The inner wall of the solid-liquid separation cylinder is provided with spiral blades for driving solids to move along the length of the solid-liquid separation cylinder. After the liquid enters the liquid storage chamber through the solid-liquid separation holes, it then enters the sedimentation tank through the water outlet pipe. The solids are discharged through the spiral blades. In a further preferred embodiment, the solids discharged by the spiral blades can also be processed in the following way: Option 1: Install an inclined scraper conveyor below the discharge end, with the conveyor speed matching the slag discharge speed of the spiral blades; connect a sealed collection bin to the end of the conveyor (the capacity is designed according to the average daily slag discharge, such as 2-3 days' worth of storage), with an exhaust port at the top of the collection bin and an activated carbon filter installed to adsorb malodorous gases, and a detachable discharge door at the bottom.

[0009] Option 2: If space is limited, a horizontal screw conveyor can be installed at the discharge end. The conveyor casing is fully sealed, and the end is connected to a temporary storage tank with a liquid level sensor. When the solids in the tank reach 80% capacity, an audible and visual alarm will be automatically triggered to remind staff to transfer the solids.

[0010] Furthermore, the middle section of the solid-liquid separation platform is provided with at least two pull-out filter assemblies located above the liquid storage chamber; the pull-out filter assembly includes a pull-out frame, on which two filter screens are provided, the lower end of each filter screen is attached to the pull-out frame, and the upper end is lower than the pull-out frame; the liquid in the solid-liquid separation cylinder enters the liquid storage chamber through the filter screen, a handle is provided on the outside of the pull-out frame, and a support leg located outside the solid-liquid separation platform is provided below the handle, the upper end of each support leg is connected to the pull-out frame, and a wheel is provided at the lower end of each support leg.

[0011] Furthermore, the solid-liquid separation platform includes a base, the pull-out filter assembly is disposed on the base, extension platforms are provided on both sides of the base, and support wheels are rotatably disposed at both ends of the base, with each support wheel located between each extension platform; both ends of the solid-liquid separation cylinder are provided with a front ring and a rear ring, which are rotatably disposed on each support wheel, and the inner sides of the front ring and the rear ring are connected by a filter cover, each solid-liquid separation hole is opened on the filter cover, and the inner wall of the filter cover is provided with a plurality of reinforcing ribs with circular cross-sections, each reinforcing rib extending along the length of the filter cover for reinforcing and supporting the filter cover; a groove is provided around the rear ring, and a toothed ring is installed in the groove; an installation port is provided on any extension platform, and a power gear is rotatably disposed at the installation port, meshing with the toothed ring and used to drive the toothed ring to rotate, the power gear being connected to the output end of the power unit, the power unit including a power housing, and a power motor being disposed inside the power housing.

[0012] Furthermore, a top plate is provided above the solid-liquid separation cylinder; inclined support parts are symmetrically arranged on both sides of the top plate, and the distance between each inclined support part gradually increases from top to bottom. Several first anti-clogging nozzles facing the solid-liquid separation cylinder are provided on the inner side of each inclined support part. Each first anti-clogging nozzle is connected to a water tank through a first pipe and is equipped with a first water pump.

[0013] Furthermore, the water tank is located at the input end of the solid-liquid separation cylinder. An extension seat is detachably mounted on the upper end of the water tank via several connecting blocks. The front half of the extension seat is suspended and extends into the solid-liquid separation cylinder. The drain pipe is mounted on the extension seat. An opening is formed in the front half of the extension seat. Several second pipes are mounted at the front end of the extension seat. Each second pipe is equipped with a second anti-clogging nozzle. Each second pipe is also connected to the main pipe. Several third pipes are located directly above the opening between the second pipes and the solid-liquid separation cylinder. Each third pipe is equipped with several third anti-clogging nozzles. Each third pipe is also connected to the main pipe via a branch pipe. A second water pump is mounted on the main pipe, and its input end is connected to the water tank. A baffle is mounted above the third pipe. The baffle is inclined and its lower end extends upwards towards the second pipe.

[0014] The aquaculture wastewater treatment and recycling method employs a double-slope design at the bottom of the land-based circular pond, with a gentle outer slope and a steep inner slope. The first slope has a gradient of 4.5%-5.5%, and the second slope has a gradient of 19%-21%. Under gravity, the aquaculture wastewater, containing uneaten feed and feces, naturally flows along the double slope towards the bottom planar positioning area, preventing wastewater from stagnating in the pond. Simultaneously, a grid installed inside the land-based circular pond, with its edge located at the junction of the first and second slopes, intercepts large debris such as uneaten feed clumps and aquatic organism remains, preventing blockage of the sewage pipe. The sewage pipe inlet is located at the center of the upper end of the planar positioning area. Once the sewage pump on the sewage pipe is activated, it transports the collected wastewater through the sewage pipe to the inlet pond. The inlet of the sewage pipe's positioning section is located at the bottom planar positioning area. The upper end of the positioning area is connected to the front end of the extension section. The extension section is inclined with a higher front and lower rear. The rear end is located in the inlet pool and connected to the input end of the sewage discharge section. Sewage is discharged into the inlet pool through the output end of the sewage discharge section. After the sewage enters the inlet pool, the solid-liquid filter plate intercepts large solid particles such as feces and uneaten feed through the filter holes. The filtered liquid enters the lower part of the inlet pool. A connecting pipe is provided on the upper outer side of the solid-liquid filter plate and connected to the inner wall of the recycling frame. The center line of the cleaning nozzle inclined on the connecting pipe is the same as the inclination direction of the solid-liquid filter plate. High-pressure flushing prevents the filter holes from clogging and pushes the intercepted solids to the inclined guide plate between the inner lower fixed plates. The solids slide down the guide plate to the recycling port of the recycling frame and are discharged, which can be used as raw material for organic fertilizer. The liquid at the bottom of the inlet tank flows into the collection well through the drain pipe, preventing the subsequent solid-liquid separation mechanism from experiencing a decrease in treatment efficiency due to fluctuations in the inlet flow rate. This brief retention period allows for thorough mixing of wastewater of different concentrations at different times, reducing the impact on water quality in subsequent treatment units. When the water level in the inlet tank is too high, the water flows back to the land-based circular tank through the overflow pipe connected to the upper part of the inlet tank, preventing leakage. In this invention, the water flowing back to the land-based circular tank not only prevents leakage but also does not affect the water quality within the land-based circular tank, for the following reasons: The water returned to the land-based circular pool is not untreated raw aquaculture wastewater, but water that has undergone deep pretreatment by the solid collection components in the inlet pool. After the above pretreatment, highly polluting large particulate matter in the returned water has been removed, and the pollutant concentration is much lower than that of the raw aquaculture wastewater. In addition, the overflow pipe in this system is connected to the upper part of the inlet pool, and most of the solid pollutants intercepted by the solid collection components are deposited at the bottom of the inlet pool and will not enter the land-based circular pool with the overflow water.

[0015] Wastewater in the collection well continues to be transported to the solid-liquid separation mechanism. A solid-liquid separation cylinder is rotatably mounted on the solid-liquid separation platform of the mechanism. A power unit drives a power gear to rotate, which meshes with a gear ring in the rear annular groove of the solid-liquid separation cylinder, causing the cylinder to rotate around a support wheel. After the wastewater enters the solid-liquid separation cylinder, under centrifugal force, the liquid passes through the solid-liquid separation holes on the filter cover of the solid-liquid separation cylinder and enters the storage chamber of the solid-liquid separation platform. The solids move along the length of the cylinder and are discharged under the push of the spiral blades on the inner wall of the solid-liquid separation cylinder. Circular reinforcing ribs on the inner wall of the filter cover extend along the length, providing reinforcement and support. At least two pull-out filter components are located above the storage chamber in the middle section of the solid-liquid separation platform. Each pull-out filter component includes a pull-out frame with two filter screens whose lower ends are attached to the frame and whose upper ends are lower than the frame. The liquid passing through the solid-liquid separation holes undergoes secondary filtration through the filter screens to remove fine suspended particles before entering the storage chamber. A handle is provided on the outside of the pull-out frame. Below the handle are support legs located outside the solid-liquid separation platform, with wheels installed at the lower ends of the support legs. A first anti-clogging nozzle washes the outer wall of the solid-liquid separation cylinder to prevent solids from adhering and clogging the solid-liquid separation holes. A water tank is located at the input end of the solid-liquid separation cylinder, with an extension seat detachably mounted on its upper end via a connecting block. The front half of the extension seat extends into the solid-liquid separation cylinder, and has an opening. A drain pipe is installed on the extension seat, and several second pipes are located at the front end of the extension seat. Each second pipe has a second anti-clogging nozzle, and all second pipes are connected to the main pipe. Several third pipes are located between the second pipes and the solid-liquid separation cylinder, directly above the opening. Each third pipe has several third anti-clogging nozzles, and all third pipes are connected to the main pipe via branch pipes. A second water pump is installed on the main pipe, with its input end connected to the water tank. After startup, the second and third anti-clogging nozzles can wash the front half of the solid-liquid separation cylinder. A baffle, inclined above the third pipes, extends upwards towards the second pipes, providing a shielding and protective function. The liquid that has undergone secondary filtration in the storage chamber of the solid-liquid separation platform is transported to the sedimentation tank through the outlet pipe that runs through the lower half of the storage chamber. The sedimentation tank causes the residual microbial flocs, tiny solid fragments and other fine suspended particles in the water to settle to the bottom of the tank by gravity. In order to further improve the effect of the sedimentation tank, as a preferred embodiment, an energy dissipation well or an arc-shaped buffer channel can be set in front of the inlet of the sedimentation tank, along with a perforated water distribution pipe and a guide plate, to reduce the flow velocity of the water entering the tank.

[0016] After treatment in the sedimentation tank, the water enters an constructed wetland, which comprises four interconnected constructed wetlands in a multi-stage series design. Utilizing the synergistic effects of aquatic plants, microorganisms, and substrates, the wetland degrades organic matter, nitrogen, phosphorus, and other pollutants, achieving deep purification. The purified water then flows into an existing pond, followed by a return water tank for temporary storage. Finally, the water in the return water tank is transported back to the land-based circular pond via an inlet pipe, realizing the recycling of aquaculture wastewater. Furthermore, the return water tank is equipped with the same water quality monitoring sensors as the land-based circular pond, used to monitor key indicators such as dissolved oxygen, pH, and ammonia nitrogen concentration in real time. When the monitored data exceeds the standard range for aquaculture water, an early warning device is automatically triggered to determine whether the water quality meets the requirements for aquaculture production.

[0017] The present invention has the following beneficial effects: 1. In this invention, the entire aquaculture wastewater treatment and recycling system starts from a land-based circular pond. A grid intercepts large impurities such as uneaten feed clumps and aquatic organism remains, preventing subsequent pipe blockage. The solid-liquid filter plate in the inlet pond uses elongated filter holes to intercept large particles such as feces and uneaten feed, while a high-pressure cleaning nozzle prevents clogging, achieving initial solid-liquid separation. The collection well temporarily stores wastewater, allowing wastewater of different times and concentrations to mix thoroughly, reducing the impact on water quality in subsequent treatment units. The solid-liquid separation mechanism uses centrifugal force to allow liquid to enter the storage chamber through the separation holes, while solids are discharged under the propulsion of spiral blades, achieving high separation accuracy. Furthermore, the pull-out filter assembly above the storage chamber can perform secondary filtration of the liquid, further removing fine suspended particles. The sedimentation tank uses gravity to settle residual microbial flocs, tiny solid fragments, and other fine suspended particulate matter in the water, reducing turbidity. Finally, the constructed wetland employs a four-stage series design, utilizing the synergistic effects of aquatic plants, microorganisms, and substrates to deeply degrade organic matter, nitrogen, phosphorus, and other pollutants, ensuring the effluent meets water quality standards and satisfies aquaculture water requirements. The inclined support section of the top plate above the solid-liquid separation cylinder is equipped with a first anti-clogging nozzle to flush the outer wall of the separation cylinder, preventing solids from adhering and clogging the separation holes. The second and third anti-clogging nozzles on the water tank extension seat flush the front half of the separation cylinder where solids are concentrated, preventing blockage at the wastewater inlet. These anti-clogging designs effectively reduce equipment downtime and ensure the continuous and stable operation of the entire purification process. 2. The return water tank in this invention can play a role in water volume regulation, making the water supply for reuse stable. Finally, the water is transported back to the land-based circular tank through the water inlet pipe, forming a cycle of aquaculture wastewater, treatment and purification, and reuse for aquaculture. Through this setting, this invention can effectively reduce the injection of new water (especially in places where water resources are scarce or inconvenient to inject water), and can significantly reduce the cost of water intake and water consumption-related expenses in aquaculture production. 3. By treating aquaculture wastewater using this invention, the purified water can be reused for aquaculture. This not only significantly reduces wastewater discharge but also avoids pollution to the surrounding water environment caused by direct wastewater discharge. At the same time, there is no wastewater discharge after treatment, the surrounding water remains clear, aquatic vegetation grows normally, effectively improving the ecological environment of the aquaculture area and its surroundings, enhancing the overall aesthetic appeal, and creating a clean and comfortable living and production environment for aquaculture workers and surrounding residents.

[0018] 4. The solid waste such as feces and uneaten feed separated by the system in this invention is discharged from the recycling port through the guide plate of the solid collection component and can be used as raw materials for organic fertilizer. These wastes were originally pollutants from aquaculture, but after recycling, they are transformed into fertilizers needed for agricultural production, bringing additional economic benefits to the farm. 5. While purifying water quality, artificial wetlands also provide ecological services to the surrounding environment through the planting of aquatic plants, including providing habitats for small organisms and promoting the balance of the ecosystem in the aquaculture area. In addition, if artificial wetlands are properly planned and developed, and combined with ornamental aquatic plants such as reeds and calamus, and facilities such as walkways and viewing platforms are set up, they can be transformed into areas that combine water purification and landscape appreciation, achieving an organic combination of agricultural aquaculture and ecotourism. This not only generates economic benefits through aquaculture but also attracts tourists based on the artificial wetland landscape, increasing tourism-related revenue, expanding the profit model of the aquaculture industry, and promoting regional economic development. 6. The bottom of the land-based circular pond adopts a double-slope design with a gentle outer slope and a steep inner slope. The first slope has a slope of 4.5%-5.5%, and the second slope has a slope of 19%-21%. This allows the aquaculture wastewater containing uneaten feed and feces to naturally collect in the bottom plane positioning area under the action of gravity, avoiding the retention of sewage in the pond, improving sewage collection efficiency, and reducing the growth of pollutants in the pond. 7. The stainless steel mesh cover at the protrusion of the water inlet pool can prevent foreign objects from falling in and facilitate the observation and maintenance of the solid collection components by the staff; the pull-out filter component of the solid-liquid separation mechanism is equipped with a handle and wheels, which can be easily pulled out and disassembled, making it convenient for cleaning and replacing the filter screen and reducing the labor intensity of equipment maintenance. Attached Figure Description

[0019] Figure 1 This is a structural schematic diagram of a specific embodiment of the present invention; Figure 2 yes Figure 1 A magnified view of the structure at point A in the middle; Figure 3 yes Figure 1 A magnified schematic diagram of the structure at point B in the middle; Figure 4 This is a partial structural schematic diagram of the land-based circular pool in this invention; Figure 5 This is a schematic diagram of the water inlet tank in this invention; Figure 6 yes Figure 5 A magnified schematic diagram of the structure at point C in the middle; Figure 7 This is a schematic diagram of the solid collection component in this invention; Figure 8 yes Figure 7 A side view of the structure without a recycling bin. Figure 9 This is a structural diagram showing the various solid-liquid filter plates and other components used together. Figure 10 yes Figure 9 A magnified schematic diagram of the structure at point D in the middle; Figure 11 This is a bottom-view three-dimensional structural diagram of the solid collection component; Figure 12 This is a schematic diagram of the solid-liquid separation mechanism in this invention; Figure 13 yes Figure 12 A schematic diagram of the three-dimensional structure; Figure 14 yes Figure 13 Another three-dimensional structural diagram; Figure 15 yes Figure 14 A magnified schematic diagram of the structure at point E in the middle; Figure 16 yes Figure 14 A magnified schematic diagram of the structure at point F in the middle; Figure 17 yes Figure 14 A magnified schematic diagram of the structure at point G in the middle; Figure 18 This is a schematic diagram of the structure where the drain pipe is installed on the extension seat; Figure 19 yes Figure 18 A partial structural diagram without baffles; Figure 20 This is a schematic diagram of the solid-liquid separation cylinder; Figure 21 This is a schematic diagram of the pull-out filter assembly; Figure 22 yes Figure 21 A schematic diagram of a structure without a filter screen. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments: When the aquaculture wastewater treatment and recycling system of this invention is applied to the cultivation of lean grass carp, it is necessary to ensure that the quality of the treated recycled water meets GB11607 (water source quality standard) and NY / T391 (fish pond water quality standard). The site selection of the farm should meet the conditions of no surrounding pollution, sufficient water source, convenient transportation, sufficient power supply and low noise interference, so as to avoid the substandard water quality affecting the quality of lean grass carp.

[0021] like Figures 1 to 22As shown, an aquaculture wastewater treatment and recycling system includes a land-based circular pond 1, which is connected to the input end of a sewage pipe 2. When using this recycling system for slimming grass carp farming, the land-based circular pond can be used as the specific implementation form. It is recommended that the land-based circular pond be designed with a diameter of 6m and a height of 1.8m, and the number can be set according to the farming scale (e.g., 20 ponds). Simultaneously, spring water is used as the initial water source, which is pre-treated in a purification pond before being connected to the recycling system to improve the initial water quality. The sewage pipe 2... The output end of pipe 2 is located above the solid collection component 3, which is installed inside the inlet pool 5. The upper half of the inlet pool 5 is connected to the lower end of the overflow pipe 6, and the upper end of the overflow pipe 6 is connected to the upper half of the land-based circular pool 1. In this invention, the land-based circular pool 1 serves as the main aquaculture unit, providing a growth environment for aquatic animals such as fish. The overflow pipe 2 connects the inlet pool and the land-based circular pool 1. When the water level in the inlet pool 5 is too high, the water flows back to the land-based circular pool through the overflow pipe 2 to prevent leakage.

[0022] The inlet pool 5 is connected in sequence to the collection well 8, the solid-liquid separation mechanism 9, and the sedimentation tank 10 via the drain pipe 7. The sedimentation tank 10 is connected to the existing pond 12 via the constructed wetland 11. The existing pond 12 is connected to the input end of the inlet pipe 15 via the return water pool 13. The output end of the inlet pipe 15 is connected to the land-based circular pond 1. The return water pool 13 temporarily stores the water purified by the constructed wetland and plays a role in water volume regulation to ensure the stability of the reuse water supply. In specific use, an ultraviolet disinfection module or an ozone disinfection device can be added to the return water pool 13 to disinfect the water purified by the constructed wetland, kill any harmful bacteria, viruses, and other microorganisms that may remain in the water, and avoid causing diseases in aquaculture organisms during the recycling process. The disinfected water must meet the microbiological index requirements in GB11607 "Fishery Water Quality Standard".

[0023] In this invention, the effective volume of the return water tank 13 needs to meet 15%-20% of the total water consumption of the land-based circular pond 1. Additionally, in practical applications, a stirring device can be installed in the return water tank 13 as needed, stirring every 2 hours to prevent water stratification and uneven water quality. Simultaneously, a booster pump with a head of 15-20m is installed on the inlet pipe 15 to ensure the return water can be smoothly delivered to the land-based circular pond 1. In the context of grass carp farming, during the treatment of tailwater using this circulation system, fish disease prevention measures must be implemented simultaneously, adhering to the principle of prevention first and treatment second. The land-based circular pond (land-based circular pond) should be disinfected monthly using different disinfectants alternately, avoiding the use of banned or discontinued drugs, and strictly adhering to the withdrawal period system to prevent drug residues from affecting water quality and grass carp quality through the circulation system. Furthermore, when reusing tailwater, the content of harmful substances in the water must be monitored to ensure compliance with aquatic product quality and safety requirements.

[0024] The water collection well 8 in this invention receives the sewage discharged from the inlet pool 5, preventing the subsequent solid-liquid separation mechanism from experiencing a decrease in treatment efficiency due to fluctuations in the inlet flow rate, including the start and stop of the sewage pump and backflow from the overflow pipe. By allowing a brief pause, sewage of different times and concentrations is thoroughly mixed, reducing the impact on water quality in subsequent treatment units, such as the risk of high-concentration pollutants entering the solid-liquid separation cylinder and causing blockage of the separation holes. The bottom of the land-based circular pool 1 includes a first slope section 16 and a second slope section 17 from the outside to the inside. The slope of the first slope section 16 is 4.5%-5.5%, and the slope of the second slope section 17 is 19%-21%. A planar positioning area 18 is provided at the bottom end of the second slope section 17, and the inlet of the sewage pipe 2 is located at the upper center of the planar positioning area 18. The area of ​​the planar positioning area 18 is 5%-8% of the total bottom area of ​​the land-based circular pool 1, and the bottom surface of the planar positioning area 18 is provided with an anti-slip coating to prevent silt accumulation at the inlet of the sewage pipe 2 due to water erosion. A grid 19 is provided inside the land-based circular pool 1. The edge of the grid 19 is located at the connection between the first slope section 16 and the second slope section 17; a water quality monitoring sensor is installed in the land-based circular pool 1 to monitor key indicators such as dissolved oxygen, pH value, and ammonia nitrogen concentration in real time. When the monitoring data exceeds the standard range for aquaculture water, an early warning device is automatically triggered; the double-slope design of the first slope section 16 and the second slope section 17, which is gentle on the outside and steep on the inside, allows the aquaculture wastewater containing uneaten feed and feces to naturally converge towards the bottom plane positioning area, avoiding the retention of sewage in the pool; the grid is set at the connection between the first slope section 16 and the second slope section 17 to intercept large-sized impurities, including uneaten feed clumps and aquatic organism remains, preventing blockage of the sewage pipe.

[0025] The constructed wetland 11 comprises a first constructed wetland 11a, a second constructed wetland 11b, a third constructed wetland 11c, and a fourth constructed wetland 11d connected in sequence. The constructed wetland in this invention adopts a multi-stage series design, utilizing the synergistic effect of aquatic plants, microorganisms, and substrates to degrade pollutants such as organic matter, nitrogen, and phosphorus, achieving deep purification. The selection of aquatic plants for the constructed wetland 11 must consider both purification effectiveness and economic efficiency, prioritizing native aquatic plants such as reeds, calamus, and cattails. The aquatic plants should be harvested every 3-6 months to prevent the decay of plant residues from polluting the water. Simultaneously, the porosity of the wetland substrate (such as gravel and expanded clay) should be regularly monitored. When the porosity falls below 60% of the initial value, part of the substrate needs to be replaced to ensure the wetland's infiltration and purification capacity.

[0026] A sewage pump is installed on the sewage pipe 2. The sewage pipe 2 includes a positioning section 20. The input end of the positioning section 20 is located at the upper end of the planar positioning area 18, and the output end of the positioning section 20 is connected to the front end of the extension section 21. As a further preferred embodiment, during actual operation, an overload protection device can also be installed at the power motor of the sewage pump and the solid-liquid separation mechanism 9. When the operating load of the equipment exceeds 120% of the rated load, the overload protection device automatically cuts off the power supply to prevent the motor from being damaged due to overload. At the same time, flow meters are installed on each pipe (sewage pipe, drainage pipe, water inlet pipe) to record water flow data in real time, which facilitates the staff to monitor the operating efficiency and water balance of each treatment unit. The rear end of the extension section 21 is located in the water inlet pool 5 and is connected to the input end of the sewage discharge section 22. The output end of the sewage discharge section 22 is located above the water inlet pool 5. The extension section 21 is inclined in a way that is higher at the front and lower at the back. The upper half of the inlet pool 5 is provided with a protrusion 23, and a stainless steel mesh cover 26 is provided at the protrusion 23. The solid collection component 3 is located below the stainless steel mesh cover 26. The stainless steel mesh cover 26 covers the protrusion of the inlet pool 5 to prevent foreign objects from falling in, and at the same time facilitates the observation and maintenance of the solid collection component by the staff. The solid collection component 3 includes a recycling frame 27, which is supported by support bars 28, and each support bar 28 is set on the inner wall of the inlet pool 5. Two solid-liquid filter plates 29 are symmetrically arranged in the recycling frame 27. Each solid-liquid filter plate 29 is inclined with the outside higher than the inside. Each solid-liquid filter plate 29 has several elongated filter holes 30. A fixing plate 31 is provided at the lower inner side of each solid-liquid filter plate 29. The fixing plates 31 are connected by guide plates 32. The solid collection assembly 3 is connected in this invention. The guide plate 32 is inclined, and its lower end is an output end for discharging solids. Several connecting pipes 33, connected to the inner wall of the recycling frame 27, are provided on the upper outer side of each solid-liquid filter plate 29. Each connecting pipe 33 extends along the length of the recycling frame 27 and is equipped with a cleaning nozzle 35. Each cleaning nozzle 35 is inclined, and its centerline is in the same direction as the inclination of the solid-liquid filter plate 29. The bottom end of the guide plate 32 is located at the recycling port 36 of the recycling frame 27. In this invention, the solid-liquid filter plate 29 of the solid collection assembly 3 intercepts large solid particles, including feces and uneaten food, in wastewater through filter holes 30. The filtered liquid enters the lower part of the inlet pool and then flows to the collection well. The inclined filter plate, combined with the cleaning nozzles, uses high-pressure flushing to prevent filter hole clogging. Simultaneously, it pushes the intercepted solids towards the guide plate, and after being discharged through the recycling port, they are used as raw materials for organic fertilizer.In addition, the solid waste such as feces and uneaten feed separated by this invention can be used as raw materials for organic fertilizer. In the case of grass carp farming, the amount generated and the frequency of collection should be recorded to avoid the accumulation of waste and pollution of the farming environment. At the same time, the cleaning cycle of the solid collection components can be adjusted according to the farming density of grass carp (for example, when the farming density of land-based circular ponds is increased to 1.2-1.5 times that of conventional ponds, the cleaning nozzle flushing frequency can be increased by 20%-30%) to ensure that the solid-liquid separation efficiency is adapted to the farming needs.

[0027] The solid-liquid separation mechanism 9 includes a solid-liquid separation platform 37, on which a solid-liquid separation cylinder 38 is rotatably mounted. The solid-liquid separation cylinder 38 has several solid-liquid separation holes 39 for discharging liquid. The solid-liquid separation platform 37 has a liquid storage chamber communicating with the solid-liquid separation holes 39. The lower half of the solid-liquid separation platform 37 is provided with a water outlet pipe 50 that passes through the liquid storage chamber. A valve is provided on the water outlet pipe 50. The valve is an electrically controlled valve that can automatically adjust its opening and closing state according to the liquid level in the liquid storage chamber. When the liquid level is higher than the preset upper limit, it automatically opens to drain water, and when it is lower than the preset lower limit, it automatically closes to prevent the liquid storage chamber from overflowing or emptying.

[0028] A power unit 51 for driving the solid-liquid separation cylinder 38 to rotate is provided on the solid-liquid separation platform 37. The inner wall of the solid-liquid separation cylinder 38 is provided with a spiral blade 52 for driving the solid to move along the length direction of the solid-liquid separation cylinder 38. After the liquid enters the liquid storage chamber through the solid-liquid separation hole 39, it enters the sedimentation tank 10 through the water outlet pipe 50. The solid is discharged through the spiral blade 52.

[0029] The sedimentation tank 10 is used to receive the liquid discharged from the solid-liquid separation module. Through gravity, the fine suspended particles remaining in the water, including microbial flocs and tiny solid fragments, settle to the bottom of the tank, further reducing the turbidity of the water and providing clean water for subsequent constructed wetland treatment. At the same time, it reduces the suspended pollutants entering the constructed wetland, avoids clogging of the wetland matrix, extends the service life of the wetland, and ensures the wetland purification efficiency. At least two pull-out filter assemblies 53 are provided in the middle section of the solid-liquid separation platform 37, located above the liquid storage chamber. Each pull-out filter assembly 53 includes a pull-out frame 55, on which two filter screens 56 are provided. The filter screens 56 are made of nylon material with a mesh size of 80-100 mesh. The mesh size of the filter screens 56 is different in the front and rear halves. The mesh size of the filter screen closer to the solid-liquid separation cylinder 38 is 80 mesh, and the mesh size of the screen further away is 100 mesh, which realizes graded filtration and improves the removal effect of fine suspended particles. At the same time, a sealing strip is provided at the contact part between the pull-out frame 55 and the solid-liquid separation platform 37 to prevent unfiltered liquid from flowing into the liquid storage chamber from the gap. The lower end of each filter screen 56 is attached to the pull-out frame 55, and the upper end is lower than the pull-out frame 55; the liquid in the solid-liquid separation cylinder 38 enters the liquid storage chamber through the filter screen 56. A handle 57 is provided on the outside of the pull-out frame 55. Below the handle 57 is a support leg 58 located outside the solid-liquid separation platform 37. The upper end of each support leg 58 is connected to the pull-out frame 55, and the lower end of each support leg 58 is provided with a traveling wheel 59.

[0030] The solid-liquid separation mechanism 9 in this invention uses centrifugal force within the solid-liquid separation cylinder 38. Liquid enters the storage chamber through the solid-liquid separation holes, while solids are discharged towards the cylinder end under the push of the spiral blades, achieving highly efficient solid-liquid separation with a separation accuracy higher than the primary filtration of the inlet tank. A pull-out filter assembly 53 is positioned above the storage chamber to perform secondary filtration on the liquid passing through the separation holes, removing fine suspended particles. The assembly is pull-out and equipped with wheels for easy cleaning and replacement of the filter screen, reducing maintenance difficulty. The solid-liquid separation platform 37 includes a base 60, the pull-out filter assembly 53 is disposed on the base 60, extension platforms 61 are provided on both sides of the base 60, and support wheels 62 are rotatably disposed at both ends of the base 60, with each support wheel 62 located between each extension platform 61; the solid-liquid separation cylinder 38 has a front end ring 63 and a rear end ring 65 at both ends, the front end ring 63 and the rear end ring 65 are respectively rotatably located on each support wheel 62, the inner sides of the front end ring 63 and the rear end ring are connected by a filter cover 66, each solid-liquid separation hole 39 is opened on the filter cover 66, and the inner wall of the filter cover 66 is provided with a plurality of reinforcing ribs 67 with a circular cross-section, each reinforcing rib 67 extending along the length of the filter cover 66 for reinforcing and supporting the filter cover 66. A groove 68 is formed around the rear end ring 65, and a toothed ring 69 is installed in the groove 68. An installation port 70 is formed on any extension platform 61, and a power gear 71 is rotatably arranged at the installation port 70, meshing with the toothed ring 69 and used to drive the toothed ring 69 to rotate. The power gear 71 is connected to the output end of the power unit 51, which includes a power housing 72, and a power motor is installed inside the power housing 72. A top plate 73 is provided above the solid-liquid separation cylinder 38; inclined support portions 75 are symmetrically arranged on both sides of the top plate 73, and the distance between each inclined support portion 75 gradually increases from top to bottom. Several first anti-clogging nozzles 76 facing the solid-liquid separation cylinder 38 are provided on the inner side of each inclined support portion 75. Each first anti-clogging nozzle 76 is connected to a water tank 78 through a first pipe 77 and is equipped with a first water pump 83.

[0031] The water tank 78 is located at the input end of the solid-liquid separation cylinder 38. An extension seat 80 is detachably mounted on the upper end of the water tank 78 via several connecting blocks 79. The front half of the extension seat 80 is suspended and extends into the solid-liquid separation cylinder 38. A drain pipe 7 is mounted on the extension seat 80. An opening 81 is formed in the front half of the extension seat 80. Several second pipes 82 are located at the front end of the extension seat 80. Each second pipe 82 is equipped with a second anti-clogging nozzle 85. Each second pipe 82 is simultaneously connected to a main pipe 86. The second pipes 82 are connected to the solid-liquid separation cylinder 38. Between the separator cylinders 38, there are several third pipes 87 located directly above the opening 81. Each third pipe 87 is equipped with several third anti-clogging nozzles 90. Each third pipe 87 is also connected to the main pipe 86 via a branch pipe 88. A second water pump 89 is installed on the main pipe 86, and its input end is connected to the water tank 78. The first anti-clogging nozzle of the inclined support 75 flushes the outer wall of the separator cylinder to prevent solids from adhering and clogging the separation holes. The second anti-clogging nozzle 85 and the third anti-clogging nozzle 90 of the extension seat flush the sewage inlet end and the solid concentration area of ​​the front half of the separator cylinder. A baffle 91 is provided above the third pipe 87. The baffle 91 is inclined and its lower end extends upwards towards the second pipe 82. The first anti-clogging nozzle is suitable for rinsing solids adhering to the solid-liquid separation cylinder 38. The second anti-clogging nozzle 85 and the third anti-clogging nozzle 90 are used to rinse the front half of the solid-liquid separation cylinder 38. When solids and liquids first enter the front half of the solid-liquid separation cylinder 38 and concentrate there, they are prone to clogging. This problem is solved by setting the second anti-clogging nozzle 85 and the third anti-clogging nozzle 90.The aquaculture wastewater treatment and recycling method employs a double-slope design at the bottom of the land-based circular pond 1, with a gentle outer slope and a steep inner slope. The first slope 16 has a gradient of 4.5%-5.5%, and the second slope 17 has a gradient of 19%-21%. Under gravity, the aquaculture wastewater containing uneaten feed and feces naturally flows along the double slopes towards the bottom planar positioning area 18, preventing wastewater from stagnating in the pond. Simultaneously, the edges of the grid 19 installed within the land-based circular pond 1 are located at the junction of the first slope 16 and the second slope 17, intercepting large impurities such as uneaten feed clumps and aquatic organism remains, preventing blockage of the sewage pipe 2. The upper center of the planar positioning area 18... The system includes an inlet for a sewage pipe 2. After the sewage pump installed on the sewage pipe 2 starts, it transports the collected sewage to the inlet pool 5 through the sewage pipe 2. The input end of the positioning section 20 of the sewage pipe 2 is located at the upper end of the planar positioning area 18, and the output end is connected to the front end of the extension section 21. The extension section 21 is inclined with a higher front and lower rear, and its rear end is located inside the inlet pool 5 and connected to the input end of the sewage discharge section 22. Sewage is discharged into the inlet pool 5 through the output end of the sewage discharge section 22. A stainless steel mesh cover 26 is installed at the upper half of the protrusion 23 of the inlet pool 5 to prevent foreign objects from falling in and to facilitate observation and maintenance. The solid collection component 3 is installed on the stainless steel mesh. Below the cover 26, a recycling frame 27 is formed by support bars 28. Two symmetrically arranged solid-liquid filter plates 29, with the outer edge higher than the inner edge, are installed inside the recycling frame 27. Several elongated filter holes 30 are formed on the plates. After sewage enters the inlet pool 5, the solid-liquid filter plates 29 intercept large solid particles such as feces and uneaten feed through the filter holes 30. The filtered liquid enters the lower part of the inlet pool 5. A connecting pipe 33 is provided on the upper outer side of the solid-liquid filter plates 29, connecting to the inner wall of the recycling frame 27. A cleaning nozzle 35, inclined on the connecting pipe 33, has its centerline aligned with the inclined direction of the solid-liquid filter plates 29, preventing clogging of the filter holes 30 through high-pressure flushing. The intercepted solids are pushed towards the inclined guide plate 32 between the inner lower fixing plates 31. The solids slide down the guide plate 32 to the recycling port 36 of the recycling frame 27 and are discharged, which can be used as raw materials for organic fertilizer. The liquid in the lower part of the inlet pool 5 flows into the collection well 8 through the drain pipe 7, which avoids the subsequent solid-liquid separation mechanism 9 from experiencing a decrease in treatment efficiency due to fluctuations in the inlet flow. Through a short stay, the sewage of different time periods and concentrations is fully mixed, reducing the water quality impact of subsequent treatment units. When the water level in the inlet pool 5 is too high, the water flows back to the land-based circular pool 1 through the overflow pipe 6 connected to the upper part of the inlet pool 5 to avoid leakage. The sewage in the collection well 8 continues to be transported to the solid-liquid separation mechanism 9. A solid-liquid separation cylinder 38 is rotatably mounted on the solid-liquid separation platform 37 of the solid-liquid separation mechanism 9. The power unit 51 drives the power gear 71 to rotate. The power gear 71 meshes with the gear ring 69 in the groove 68 of the rear end ring 65 of the solid-liquid separation cylinder 38, causing the solid-liquid separation cylinder 38 to rotate around the support wheel 62. After the sewage enters the solid-liquid separation cylinder 38, under the action of centrifugal force, the liquid enters the liquid storage chamber of the solid-liquid separation platform 37 through the solid-liquid separation hole 39 on the filter cover 66 of the solid-liquid separation cylinder 38, while the solid moves along the length of the cylinder and is discharged under the push of the spiral blades 52 on the inner wall of the solid-liquid separation cylinder 38. The circular reinforcing ribs 67 on the inner wall of the filter cover 66 move along the length of the cylinder. The extension provides reinforcement and support for the filter cover 66; at least two pull-out filter components 53 are installed in the middle section of the solid-liquid separation platform 37 above the liquid storage chamber. Each pull-out filter component 53 includes a pull-out frame 55, on which are two filter screens 56 with their lower ends attached to the frame and their upper ends lower than the frame. The liquid passing through the solid-liquid separation hole 39 is first filtered twice by the filter screens 56 to remove fine suspended particles before entering the liquid storage chamber. A handle 57 is provided on the outside of the pull-out frame 55, and a support leg 58 is provided below the handle 57 outside the solid-liquid separation platform 37. The lower end of the support leg 58 is equipped with a traveling wheel 59 to facilitate pulling out the pull-out frame 55 and removing the filter screens 56 for cleaning and replacement; a top plate 7 is provided above the solid-liquid separation cylinder 38. 3. The top plate 73 has symmetrically arranged inclined support parts 75 on both sides, with the spacing between the inclined support parts 75 gradually increasing from top to bottom. Several first anti-clogging nozzles 76 facing the solid-liquid separation cylinder 38 are provided on the inner side. The first anti-clogging nozzles 76 are connected to the water tank 78 through a first pipe 77. A first water pump 83 is installed on the first pipe 77 to flush the outer wall of the solid-liquid separation cylinder 38 through the first anti-clogging nozzles 76, preventing solids from adhering and clogging the solid-liquid separation holes 39. The water tank 78 is located at the input end of the solid-liquid separation cylinder 38, and an extension seat 80 is detachably installed on its upper end via a connecting block 79. The front half of the extension seat 80 extends into the solid-liquid separation cylinder 38, and the front half has an opening 81. A drain pipe 7 is installed on the extension seat 80, and the front end of the extension seat 80 has a... Several second pipes 82 are provided, each equipped with a second anti-clogging nozzle 85, and all second pipes 82 are connected to the main pipe 86. Several third pipes 87 are provided between the second pipes 82 and the solid-liquid separation cylinder 38, directly above the opening 81, and each third pipe 87 is equipped with several third anti-clogging nozzles 90. All third pipes 87 are connected to the main pipe 86 through branch pipes 88. A second water pump 89 is provided on the main pipe 86, with its input end connected to a water tank 78. After starting, the second anti-clogging nozzles 85 and the third anti-clogging nozzles 90 can flush the first half of the solid-liquid separation cylinder 38. The lower end of the baffle 91 inclined above the third pipes 87 extends upwards towards the second pipes 82, serving as a shield and protection function. The liquid that has undergone secondary filtration in the storage chamber of the solid-liquid separation platform 37 is transported to the sedimentation tank 10 through the outlet pipe 50 that runs through the lower half of the storage chamber. In the sedimentation tank 10, gravity causes residual microbial flocs, tiny solid fragments, and other fine suspended particles to settle to the bottom, further reducing the turbidity of the water. This provides clean influent for subsequent treatment in the constructed wetland 11, while also reducing suspended pollutants entering the constructed wetland 11, preventing clogging of the wetland substrate, and extending the wetland's lifespan. The water treated in the sedimentation tank 10 then enters the constructed wetland 11, which comprises a first constructed wetland 11a, a second constructed wetland 11b, a third constructed wetland 11c, and a fourth constructed wetland 11d connected in sequence. This multi-stage series design utilizes the synergistic effects of aquatic plants, microorganisms, and the substrate. The system degrades organic matter, nitrogen, phosphorus, and other pollutants in the water, achieving deep purification. The water purified by the artificial wetland 11 enters the constructed pond 12 and then flows into the return water pond 13 for temporary storage. The return water pond 13 plays a role in water volume regulation, ensuring the stability of the reuse water supply. Finally, the water in the return water pond 13 is transported back to the land-based circular pond 1 through the inlet pipe 15, realizing the recycling of aquaculture tailwater. When the tailwater treated by this recycling system is reused for the cultivation of lean grass carp, it needs to be combined with the lean cultivation cycle management. Referring to the research results, the optimal lean cycle should be determined based on the changes in the fatness, muscle protein content, muscle fat content, elasticity, collagen, and fishy substances of grass carp, to ensure that the reused water maintains a clean environment required for the growth of grass carp during the lean period, improves the firmness of the lean grass carp meat, and reduces the muddy taste.

Claims

1. A wastewater treatment and recycling system for aquaculture, characterized in that: It includes a land-based circular pool (1), the land-based circular pool (1) is connected to the input end of a sewage pipe (2), the output end of the sewage pipe (2) is located above a solid collection component (3), the solid collection component (3) is set in an inlet pool (5), the upper half of the inlet pool (5) is connected to the lower end of an overflow pipe (6), and the upper end of the overflow pipe (6) is connected to the upper half of the land-based circular pool (1); The inlet pool (5) is connected in sequence to the collection well (8), the solid-liquid separation mechanism (9) and the sedimentation tank (10) via the drain pipe (7). The sedimentation tank (10) is connected to the existing pool (12) via the artificial wetland (11). The existing pool (12) is connected to the input end of the inlet pipe (15) via the return pool (13). The output end of the inlet pipe (15) is connected to the land-based circular pool (1). A grid (19) is installed inside the land-based circular pool (1). The upper half of the water inlet pool (5) is provided with a boss (23), and a stainless steel mesh cover (26) is provided at the boss (23). The solid collection component (3) is located below the stainless steel mesh cover (26). The solid collection component (3) includes a recycling frame (27), which is supported by support bars (28), and each support bar (28) is provided on the inner wall of the water inlet pool (5); Two solid-liquid filter plates (29) are symmetrically arranged inside the recycling box (27). Each solid-liquid filter plate (29) is inclined with the outside higher than the inside. Each solid-liquid filter plate (29) has several elongated filter holes (30). Each solid-liquid filter plate (29) has a fixing plate (31) at the lower inner side. Each fixing plate (31) is connected to each other by a guide plate (32). The guide plate (32) is inclined. The lower end of the guide plate (32) is the output end for discharging solids. Each of the solid-liquid filter plates (29) has several connecting pipes (33) on its outer upper side that are connected to the inner wall of the recycling frame (27). Each of the connecting pipes (33) extends along the length of the recycling frame (27) and is equipped with a cleaning nozzle (35). Each of the cleaning nozzles (35) is inclined and its center line is in the same direction as the inclination of the solid-liquid filter plate (29). The bottom end of the guide plate (32) is located at the recycling port (36) of the recycling frame (27). The solid-liquid separation mechanism (9) includes a solid-liquid separation platform (37), a solid-liquid separation cylinder (38) is rotatably arranged on the solid-liquid separation platform (37), a plurality of solid-liquid separation holes (39) for discharging liquid are opened on the solid-liquid separation cylinder (38), the solid-liquid separation platform (37) has a liquid storage cavity communicating with the solid-liquid separation holes (39), the lower half of the solid-liquid separation platform (37) is provided with a water outlet pipe (50) that penetrates the liquid storage cavity, and a valve is provided on the water outlet pipe (50); The power unit (51) for driving the solid-liquid separation cylinder (38) to rotate is set on the solid-liquid separation platform (37). The inner wall of the solid-liquid separation cylinder (38) is provided with a spiral blade (52) for driving the solid to move along the length direction of the solid-liquid separation cylinder (38). After the liquid enters the storage chamber through the solid-liquid separation hole (39), it enters the sedimentation tank (10) through the water outlet pipe (50). The solid is discharged through the spiral blade (52). The solid-liquid separation stage (37) is provided with at least two pull-out filter components (53) located above the liquid storage chamber in the middle section. The pull-out filter assembly (53) includes a pull-out frame (55), on which two filter screens (56) are provided. The lower end of each filter screen (56) is attached to the pull-out frame (55), and the upper end is lower than the pull-out frame (55). The liquid in the solid-liquid separation cylinder (38) enters the liquid storage chamber through the filter screens (56). A handle (57) is provided on the outside of the pull-out frame (55). Below the handle (57) are support legs (58) located outside the solid-liquid separation platform (37). The upper end of each support leg (58) is connected to the pull-out frame (55), and the lower end of each support leg (58) is provided with a traveling wheel (59). A top plate (73) is provided above the solid-liquid separation cylinder (38); inclined support parts (75) are symmetrically arranged on both sides of the top plate (73), and the distance between each inclined support part (75) gradually increases from top to bottom. Each inclined support part (75) has a number of first anti-clogging nozzles (76) facing the solid-liquid separation cylinder (38) on its inner side. Each first anti-clogging nozzle (76) is connected to the water tank (78) through a first pipe (77) and is equipped with a first water pump (83). The water tank (78) is located at the input end of the solid-liquid separation cylinder (38). An extension seat (80) is detachably provided on the upper end of the water tank (78) through several connecting blocks (79). The front half of the extension seat (80) is suspended and extends into the solid-liquid separation cylinder (38). The drain pipe (7) is provided on the extension seat (80). An opening (81) is opened on the front half of the extension seat (80). Several second pipes (82) are provided at the front end of the extension seat (80). A second anti-clogging nozzle (85) is provided on each second pipe (82). Each second pipe (82) is connected to the main pipe (86). Between the second pipe (82) and the solid-liquid separation cylinder (38), there are several third pipes (87) located directly above the opening (81). Each of the third pipes (87) is equipped with several third anti-clogging nozzles (90). Each of the third pipes (87) is connected to the main pipe (86) through a branch pipe (88). The main pipe (86) is equipped with a second water pump (89), and its input end is connected to the water tank (78). A baffle (91) is provided above the third pipe (87), the baffle (91) is inclined and its lower end extends above the second pipe (82).

2. The aquaculture wastewater treatment and recycling system as described in claim 1, characterized in that: The bottom of the land-based circular pool (1) includes a first slope section (16) and a second slope section (17) from the outside to the inside. The slope of the first slope section (16) is 4.5%-5.5%, and the slope of the second slope section (17) is 19%-21%. The bottom end of the second slope section (17) is provided with a planar positioning area (18), and the inlet of the sewage pipe (2) is located at the upper center of the planar positioning area (18); The edge of the grid (19) is located at the connection between the first slope section (16) and the second slope section (17). A water quality monitoring sensor is installed in the land-based circular pool (1) to monitor the dissolved oxygen, pH value and ammonia nitrogen concentration in the water in real time. When the monitoring data exceeds the standard range for aquaculture water, an early warning device is automatically triggered. The constructed wetland (11) includes a first constructed wetland (11a), a second constructed wetland (11b), a third constructed wetland (11c), and a fourth constructed wetland (11d) connected in sequence.

3. The aquaculture wastewater treatment and recycling system as described in claim 2, characterized in that: A sewage pump is installed on the sewage pipe (2). The sewage pipe (2) includes a positioning section (20). The input end of the positioning section (20) is located at the upper end of the planar positioning area (18). The output end of the positioning section (20) is connected to the front end of the extension section (21). The rear end of the extension section (21) is located in the water inlet pool (5) and is connected to the input end of the sewage discharge section (22). The output end of the sewage discharge section (22) is located above the water inlet pool (5). The extension section (21) is inclined in a way that is higher in the front and lower in the back.

4. The aquaculture wastewater treatment and recycling system as described in claim 3, characterized in that: The solid-liquid separation stage (37) includes a base (60), the pull-out filter assembly (53) is disposed on the base (60), and extension stages (61) are provided on both sides of the base (60). Support wheels (62) are rotatably provided at both ends of the base (60), and each support wheel (62) is located between each extension stage (61). Both ends of the solid-liquid separation cylinder (38) are provided with a front end ring (63) and a rear end ring (65). The front end ring (63) and the rear end ring (65) are respectively rotatably located on each of the support wheels (62). The inner sides of the front end ring (63) and the rear end ring (65) are connected by a filter cover (66). Each of the solid-liquid separation holes (39) is opened on the filter cover (66). The inner wall of the filter cover (66) is provided with a number of reinforcing ribs (67) with a circular cross-section. Each reinforcing rib (67) extends along the length of the filter cover (66) to reinforce and support the filter cover (66). A groove (68) is provided around the rear end ring (65), and a toothed ring (69) is installed in the groove (68). An installation port (70) is provided on any extension platform (61). A power gear (71) is rotatably provided at the installation port (70) to mesh with the toothed ring (69) and drive the toothed ring (69) to rotate. The power gear (71) is connected to the output end of the power unit (51). The power unit (51) includes a power housing (72), and a power motor is provided inside the power housing (72).

5. A method for treating and recycling aquaculture wastewater based on the aquaculture wastewater treatment and recycling system as described in claim 4, characterized in that: Under the influence of gravity, the aquaculture wastewater containing uneaten feed and feces naturally flows along the double slope section to the bottom plane positioning area (18); after the sewage pump installed on the sewage pipe (2) is started, the collected sewage is transported to the inlet pool (5) through the sewage pipe (2). After the sewage enters the inlet pool (5), the solid-liquid filter plate (29) intercepts feces and large particles of uneaten feed through the filter holes (30), and the filtered liquid enters the lower part of the inlet pool (5); the filter holes (30) are prevented from being blocked by high pressure flushing, and the intercepted solids are pushed to the guide plate (32). The solids slide down the guide plate (32) to the recycling port (36) of the recycling frame (27) and are discharged. The liquid in the lower part of the inlet pool (5) flows into the collection well (8) through the drain pipe (7), so that the sewage of different time periods and different concentrations are fully mixed; when the water level in the inlet pool (5) is too high due to untimely treatment, the water flows back to the land-based circular pool (1) through the overflow pipe (6) connected to the upper part of the inlet pool (5). The sewage in the collection well (8) continues to be transported to the solid-liquid separation mechanism (9). The power unit (51) drives the solid-liquid separation cylinder (38) to rotate around the support wheel (62). After the sewage enters the solid-liquid separation cylinder (38), under the action of centrifugal force, the liquid enters the storage chamber of the solid-liquid separation platform (37) through the solid-liquid separation hole (39) on the filter cover (66) of the solid-liquid separation cylinder (38). The solid moves along the length of the cylinder and is discharged under the push of the spiral blades (52) on the inner wall of the solid-liquid separation cylinder (38). The liquid passing through the solid-liquid separation hole (39) is first filtered twice by the filter screen (56) to remove fine suspended particles before entering the storage chamber. The outer wall of the solid-liquid separation cylinder (38) is rinsed by the first anti-clogging nozzle (76) to prevent solids from adhering and clogging the solid-liquid separation hole (39). The second anti-clogging nozzle (85) and the third anti-clogging nozzle (90) can rinse the first half of the solid-liquid separation cylinder (38). The liquid that has undergone secondary filtration in the storage chamber of the solid-liquid separation platform (37) is transported to the sedimentation tank (10) through the water outlet pipe (50) that runs through the lower half of the storage chamber. The sedimentation tank (10) causes the residual microbial flocs, tiny solid fragments and fine suspended particles in the water to settle to the bottom of the tank by gravity. After treatment in the sedimentation tank (10), the water enters the constructed wetland (11). The constructed wetland (11) adopts a multi-stage series design and utilizes the synergistic effect of aquatic plants, microorganisms and substrates to degrade organic matter and nitrogen and phosphorus pollutants in the water to achieve deep purification. The water purified by the constructed wetland (11) enters the constructed pond (12) and then flows into the return water pond (13) for temporary storage. Finally, the water in the return water pond (13) is transported back to the land-based circular pond (1) through the inlet pipe (15) to achieve the recycling of aquaculture wastewater.

Images