Fresh water circulation aquaculture whole-process water treatment system and method

Abstract

The invention discloses a fresh water circulating aquaculture whole-process water treatment system and method, and belongs to the technical field of circulating aquaculture water treatment. The system comprises an inlet water treatment subsystem, a culture pond subsystem and a tail water treatment subsystem which are sequentially and circularly communicated, the water inlet treatment subsystem comprises a water storage tank, a sand filtering tank and a filtered water tank which are communicated in sequence; the culture pond subsystem comprises a plurality of culture pond circulating combinations, and each culture pond circulating combination comprises a culture pond cluster, a first microfilter, a circulating pump pond, a biological aerated filter, a disinfection pond, a decarburization device and an oxygenation temperature regulation pond which are sequentially and circularly communicated; the tail water treatment subsystem comprises a second microfilter, a sulfur autotrophic denitrification tank and an SBR (sequencing batch reactor) reaction tank cluster which are communicated in sequence. The system integrates fresh water circulating water treatment, tail water treatment and source water treatment, can meet the requirements of medium and large fresh water circulating aquaculture factories on aquaculture water quality, can save the occupied area and investment, and meets the requirements of green sustainable development.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology for recirculating aquaculture, specifically to a complete water treatment system and method for freshwater recirculating aquaculture. Background Technology

[0002] In recent years, in order to meet the requirements of the new strategy for green development in the aquaculture industry, freshwater recirculating aquaculture has gradually gained popularity. Its stocking density can reach 50 kg / m³. 3 The yield is dozens of times higher than that of traditional freshwater aquaculture, significantly improving space utilization. Furthermore, freshwater recirculating aquaculture achieves a water recycling rate of over 90%, greatly reducing dependence on water sources, allowing for controllable production conditions, high yields, low wastewater discharge, and environmental friendliness.

[0003] Water treatment is a core component of freshwater recirculating aquaculture, and current research primarily focuses on recirculating water treatment processes. To address the high sensitivity of aquaculture to water quality and the discharge requirements of receiving water bodies, it is necessary to adopt a holistic approach to water treatment, ensuring efficient and coordinated treatment and regulation of recirculating water, effluent, and source water. In freshwater recirculating aquaculture source water treatment, some farms still use elevated water tanks, which require significant land area, experience fluctuations in water volume and pressure, and struggle to guarantee a stable water supply. Effluent treatment often employs a three-pond, two-dam system, which occupies considerable space, and the effluent may not meet discharge or reuse requirements during low winter temperatures. While recirculating water treatment processes are relatively mature, various combinations exist, necessitating the development of a technically feasible and economically reasonable recirculating water treatment process to meet the requirements of efficient holistic water treatment. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a complete freshwater recirculating aquaculture water treatment system and method. This system and method integrate freshwater recirculating water treatment, tailwater treatment, and source water treatment, which can meet the water quality requirements of medium and large-scale freshwater recirculating aquaculture farms. At the same time, it can save land area and investment, and meet the requirements of green and sustainable development.

[0005] To achieve the above objectives, the present invention designs a freshwater recirculating aquaculture full-process water treatment system, comprising an influent treatment subsystem, an aquaculture pond subsystem, and a tailwater treatment subsystem connected in sequence. The influent treatment subsystem includes a water storage tank, a sand filter tank, and a filtered water tank connected in sequence. The filtered water tank is equipped with a first ozone disinfection device and a constant pressure water supply device in sequence. The aquaculture pond subsystem includes multiple aquaculture ponds in a circulating combination. The aquaculture pond circulation combination includes an aquaculture pond cluster connected in sequence, a first microfilter, a circulating pump tank, an aerated biological filter, a disinfection tank, a decarbonization device, and an oxygenation and temperature regulation tank. The tailwater treatment subsystem includes a second microfilter, a sulfur autotrophic denitrification tank, and an SBR reactor cluster connected in sequence.

[0006] Preferably, the aquaculture pond cluster includes multiple parallel aquaculture pond groups, each aquaculture pond group consisting of multiple aquaculture pond units arranged longitudinally. Adjacent aquaculture pond groups are provided with matching supernatant outlet main pipes and sediment outlet main pipes, with the sediment outlet main pipe located directly below the supernatant outlet main pipe.

[0007] Preferably, the aquaculture pond unit includes a pond body with a funnel-shaped bottom. An inlet pipe is located at the top of the pond body, a pre-filter is located at the center of the bottom of the pond body, an aeration device is located in the bottom area of ​​the pond body, a filtrate outlet pipe and a vent pipe are located at the bottom of the pre-filter, and a vent pipe shut-off valve is located on the vent pipe. A feeder is located on the pond wall, and a vertical flow sedimentator is located beside the pond body. The filtrate outlet pipe is connected to the vertical flow sedimentator, and a supernatant outlet branch pipe is located at the top of the vertical flow sedimentator, while a sediment outlet branch pipe is located at the bottom. An overflow box is located in the top area of ​​the outer wall of the pond body, and an overflow port connected to the overflow box is located on the outer wall of the pond body. An overflow pipe and a drain pipe are located inside the overflow box, with the inlet end of the drain pipe located at the bottom of the overflow box and the inlet end of the overflow pipe located in the top area inside the overflow box.

[0008] Preferably, the supernatant outlet branch pipe and the drain pipe are connected to the supernatant outlet main pipe, and the vent pipe, the overflow pipe and the sediment outlet branch pipe are connected to the sediment outlet main pipe.

[0009] Preferably, a sludge tank is located next to the second microfilter, and the sludge discharge port of the second microfilter is connected to the sludge tank. The supernatant outlet pipe of the sludge tank is connected to the sulfur autotrophic denitrification tank. The main sludge discharge pipe of the SBR reactor cluster is connected to the sludge tank. A screw press is located next to the sludge tank, and the sludge discharge pipe of the sludge tank is connected to the sludge inlet of the screw press. The filtrate pipe of the screw press is connected to the sulfur autotrophic denitrification tank. The sludge discharge pipe of the first microfilter is connected to the second microfilter. The sludge discharge pipe of the aerated biological filter is connected to the second microfilter. The outlet pipe of the constant pressure water supply device is connected to the circulating pump pool. A pH adjustment device is installed in the circulating pump pool. A second ozone disinfection device and an ultraviolet disinfection device are installed in the disinfection tank.

[0010] Preferably, the central area of ​​the sulfur autotrophic denitrification tank is provided with a pipe gallery, which divides the sulfur autotrophic denitrification tank into two denitrification zones. Each denitrification zone has a filter media layer in the middle. The pipe gallery is arranged along the direction of the sulfur autotrophic denitrification tank by two gallery walls. A first partition wall is horizontally arranged above the two gallery walls, which divides the pipe gallery into an upper drainage channel area and a lower pipe gallery area. A drainage component communicating with the drainage channel area is arranged below the first partition wall. A filter inlet main pipe is arranged in the pipe gallery area, and the filter inlet main pipe is arranged along the direction of the pipe gallery area. Inlet branch pipes are arranged at intervals on the filter inlet main pipe, and each inlet branch pipe extends through the gallery wall to the bottom of the filter media layer. A return pipe is provided at the top of the inner wall of each denitrification zone, and a return pump is provided on the return pipe. The return pipes are all connected to the filter inlet main pipe.

[0011] Preferably, two rows of vertical and symmetric second partition walls are arranged along the direction of the pipe gallery area in the drainage trough area. The two rows of second partition walls divide the drainage trough area into a filtrate outlet trough on both sides and a sewage outlet trough in the middle. The drainage component includes two filtrate outlet main pipes and one sewage outlet main pipe, and the filtrate outlet main pipe and the sewage outlet main pipe are correspondingly arranged with the filtrate outlet trough and the sewage outlet trough in the middle. One or more filtrate outlet branch pipes are connected between the filtrate outlet main pipe and the filtrate outlet trough, and one or more sewage outlet branch pipes are connected between the sewage outlet main pipe and the sewage outlet trough. An anti-flushing inlet main pipe supporting the denitrification area is arranged in the pipe gallery area. The anti-flushing inlet main pipe is arranged along the direction of the pipe gallery area. A plurality of anti-flushing inlet branch pipes are connected to the pipe wall of the anti-flushing inlet main pipe, and the outlet of the anti-flushing inlet branch pipe is arranged below the filter material layer. An air inlet main pipe is arranged in the pipe gallery area. The air inlet main pipe is arranged along the direction of the pipe gallery area. A plurality of air inlet branch pipes are arranged on the pipe wall of the air inlet main pipe. The plurality of air inlet branch pipes are evenly spaced and distributed below the filter material layer. A plurality of air outlet micropores are evenly distributed on the pipe wall of the air inlet branch pipe. Valves are arranged on the inlet branch pipe, the anti-flushing inlet branch pipe, the air inlet branch pipe, the filtrate outlet branch pipe, the sewage outlet branch pipe and the return pipe. The filter material layer includes a supporting filter plate and a single-element sulfur filter material layer. The side wall of the supporting filter plate is fixed on the inner wall of the sulfur autotrophic denitrification pond body, and the single-element sulfur filter material layer is placed above the supporting filter plate.

[0012] Preferably, the SBR reaction tank cluster is composed of a plurality of SBR reaction tanks connected in parallel. Suspended fillers are placed in the SBR reaction tanks. A plurality of aerators are arranged at the bottom of the SBR reaction tanks. A plurality of air delivery main pipes are arranged at the top of the SBR reaction tanks. A plurality of air delivery branch pipes are arranged on each air delivery main pipe. Each air delivery branch pipe is connected to an aerator. An air pump is arranged at the air inlet end of the air delivery main pipe. A circulation pump is arranged beside the SBR reaction tank. A water suction pipe and a return water main pipe are arranged on the circulation pump. A plurality of return water branch pipes are arranged on the return water pipe. Each return water branch pipe is connected to an aerator. A reaction tank inlet pipe is arranged on the SBR reaction tank. The reaction tank inlet pipes are all connected to the supernatant outlet pipe of the sulfur autotrophic denitrification pond. A water decanter is arranged in the SBR reaction tank. The water decanter is arranged at the tail of the tank along the width direction of the tank surface. An outlet pipe is arranged in the water decanter. Valves are arranged on the air delivery branch pipe, the return water branch pipe and the inlet pipe.

[0013] The present invention also designs a full-process water treatment method for freshwater circulating aquaculture. The method is realized based on a full-process water treatment system for freshwater circulating aquaculture and includes the following steps: S1. Source water treatment and constant pressure water replenishment process: External source water or treated wastewater is introduced into the storage tank for storage and pretreatment. Sodium hypochlorite is added to inhibit microbial growth and precipitate particulate matter. The water from the storage tank is then pumped to a sand filter tank for filtration to remove suspended solids, colloids and some organic matter. The filtered water is stored in the filtered water tank and sterilized by the first ozone disinfection device. Then, a constant pressure water supply device installed in the tank provides constant flow and pressure water replenishment to the circulation pump tank of the aquaculture tank subsystem. S2. Circulating water treatment and internal circulation process: S2.1, Aquaculture wastewater diversion and collection: The wastewater generated by the aquaculture pond unit is collected in diversion. The supernatant collected by the top overflow box and the supernatant collected by the vertical flow sedimentator are merged into the supernatant outlet main pipe. The sediment discharged by the bottom pre-filter, the sediment collected by the vertical flow sedimentator and the overflow collected by the overflow pipe are merged into the sediment outlet main pipe. S2.2 Physical filtration: The supernatant is sent to the first microfilter for filtration; S2.3 Water quality adjustment: The filtered water is sent into the circulating pump pool and the pH of the water is adjusted by a pH adjustment device; S2.4 Biological purification: The effluent from the circulating pump tank is pumped into the aerated biological filter tank, and the organic matter, ammonia nitrogen and nitrite nitrogen in the water are degraded by the biofilm method. S2.5 Disinfection treatment: The effluent from the biological filter is passed into the disinfection tank and disinfected in combination using a second ozone disinfection device and an ultraviolet disinfection device; S2.6 Decarbonization treatment: The disinfected effluent is sent to the decarbonization device, where excess carbon dioxide and residual ozone in the water are removed by aeration. S2.7 Oxygenation, Temperature Regulation and Recirculation: The treated water is sent to the oxygenation and temperature regulation tank for dissolved oxygen replenishment and temperature regulation, and then returned to each aquaculture tank unit through the inlet pipe. S3. Wastewater Treatment and Resource Reuse Process: High-concentration wastewater from the effluent main pipe of the sediment is filtered through a second microfilter; the filtrate from the second microfilter is passed into a sulfur autotrophic denitrification tank to remove nitrate nitrogen using sulfur autotrophic denitrification; the effluent from the sulfur autotrophic denitrification tank is passed into an SBR reactor cluster for advanced treatment using the sequencing batch reactor (SBR) activated sludge process; the treated effluent from the SBR reactor cluster is transported to a storage tank as a reclaimed water source.

[0014] Preferably, in step S3, the filter residue produced by the second microfilter is transported to the sludge tank. After the sludge is concentrated in the sludge tank, the supernatant is transported to the sulfur autotrophic denitrification tank, the sludge is transported to the screw press, and after dewatering treatment by the screw press, the dewatered filtrate is transported to the sulfur autotrophic denitrification tank, and the sludge cake is transported off-site for treatment; the sludge discharged from the SBR reactor cluster is transported to the sludge tank.

[0015] The beneficial effects of this invention are: 1. High system integration and stable operation: This invention is the first to organically connect the three subsystems of influent treatment, circulating water treatment and effluent treatment into a complete closed-loop treatment system, realizing internal circulation and near-zero discharge of aquaculture water, with extremely low dependence on external water sources, and more stable and reliable water quality control.

[0016] 2. High efficiency in wastewater treatment and space saving: This invention replaces the traditional "three pools and two dams" process by setting up a wastewater treatment subsystem that integrates a sulfur autotrophic denitrification tank and an SBR reactor cluster, which greatly saves land area, has high treatment efficiency, strong resistance to shock loads, and is especially suitable for wastewater with high nitrate nitrogen content generated by high-density aquaculture, and can achieve more than 95% wastewater reuse.

[0017] 3. Stable water supply and avoidance of secondary pollution: The water treatment subsystem of this invention adopts a constant pressure water supply device consisting of a variable frequency pump and a pressure stabilizing tank, which replaces the traditional high-level water tank. This not only saves space but also ensures that the flow rate and pressure of water replenished to the circulation system are constant, avoiding the risk of secondary pollution that may be caused by the water tank.

[0018] 4. Optimized Circulation Process for Energy Saving and Consumption Reduction: The aquaculture pond subsystem of this invention features a rational process design, placing the decarbonization device after the disinfection tank to effectively remove carbon dioxide generated from biodegradation and residual ozone after ozone disinfection, protecting the safety of aquaculture organisms. The oxygenation and temperature regulation tank integrates oxygenation and temperature regulation functions in a compact structure. Furthermore, by installing an aeration device within the aquaculture pond, it can be used in conjunction with an oxygen cone to supply oxygen, improving oxygen utilization. It can also operate independently at low stocking densities, saving operational energy.

[0019] 5. Flexible layout and strong applicability: The multiple core processing units in the system of this invention (such as microfilters, decarbonization devices, SBR reaction tank clusters, etc.) can be modularly designed, which makes it easy to flexibly lay out and expand according to the actual site and aquaculture scale, making it very suitable for medium and large freshwater recirculating aquaculture farms. Attached Figure Description

[0020] Figure 1 This is a flowchart of the whole-process water treatment system for freshwater recirculating aquaculture in this invention; Figure 2 This is a structural diagram of the aquaculture pond cluster and the supernatant effluent main pipe of the present invention; Figure 3 This is a structural diagram of the aquaculture pond assembly and the supernatant outlet pipe of the present invention; Figure 4 This is a structural diagram of the aquaculture pond cluster and the main effluent outlet pipe of the sedimentation liquid of the present invention; Figure 5 This is a structural diagram of the aquaculture pond assembly and the main outlet pipe for the sedimentation liquid of the present invention; Figure 6 This is a structural diagram of the aquaculture pond unit of the present invention; Figure 7 This is a structural diagram of the sulfur autotrophic denitrification tank of the present invention; Figure 8 This is a structural diagram of the SBR reactor of the present invention; Figure 9 This is a flowchart of the whole-process water treatment method for freshwater recirculating aquaculture according to the present invention.

[0021] Figure label: 1. Inlet water treatment subsystem, 11. Water storage tank, 12. Sand filter tank, 13. Filtered water tank, 131. First ozone disinfection device, 132. Constant pressure water supply device. 2. Aquaculture pond circulation system; 21. Aquaculture pond cluster; 211. Supernatant effluent main pipe; 212. Sediment effluent main pipe; 210. Aquaculture pond unit; 213. Pond body; 214. Inlet pipe; 215. Pre-filter; 2151. Filtration effluent pipe; 2152. Vent pipe; 2153. Vent pipe shut-off valve; 216. Feeder; 217. Vertical flow sedimentator; 2171. Supernatant effluent branch pipe; 2172. Sediment effluent branch pipe; 218. Overflow box; 2181. Overflow pipe; 2182. Drainage pipe; 22. First microfilter; 23. Circulation pump tank; 231. pH adjustment device; 24. Aerated biological filter; 25. Disinfection tank; 251. Second ozone disinfection device; 252. Ultraviolet disinfection device; 26. Decarbonization device; 27. Oxygenation and temperature control tank. 3. Wastewater Treatment Subsystem; 31. Second Microfilter; 32. Sulfur Autotrophic Denitrification Tank; 321. Denitrification Zone; 322. Filter Media Layer; 3221. Support Filter Plate; 3222. Elemental Sulfur Filter Media Layer; 323. Corridor Wall; 324. First Partition Wall; 325. Drainage Channel Area; 3251. Second Partition Wall; 3252. Filtrate Outlet Channel; 3253. Wastewater Outlet Channel; 326. Pipe Gallery Area; 3261. Filter Inlet Main Pipe; 3262. Inlet Branch Pipe; 3263. Backwash Inlet Main Pipe; 3264. Backwash Inlet Branch Pipe; 3265. Air Inlet Main Pipe; 3266. Air Inlet Branch Pipe; 327. Drainage Components; 3271. Filtrate Outlet Main Pipe; 3272. Wastewater Outlet Main Pipe; 3273. Filtrate Outlet Branch Pipe; 3274. Wastewater Outlet Branch Pipe; 328. Return pipe, 33 SBR reactor, 331 aerator, 332 air pump, 333 circulating pump, 334 main air supply pipe, 3341 branch air supply pipe, 335 suction pipe, 336 main return water pipe, 3361 branch return water pipe, 337 reactor inlet pipe, 338 decanter, 3381 outlet pipe, 339 suspended packing, 34 sludge tank, 35 screw press. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0023] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0024] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0026] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1 like Figures 1-8The freshwater recirculating aquaculture system shown includes an influent treatment subsystem 1, an aquaculture pond subsystem, and an effluent treatment subsystem 3, which are connected in a sequential cycle. The influent treatment subsystem 1 includes a water storage tank 11, a sand filter tank 12, and a filtered water tank 13, which are connected in a sequential cycle. The filtered water tank 13 is equipped with a first ozone disinfection device 131 and a constant pressure water supply device 132. The aquaculture pond subsystem includes multiple aquaculture pond circulation combinations 2, which include an aquaculture pond cluster 21, a first microfilter 22, a circulating pump tank 23, an aerated biological filter 24, a disinfection tank 25, a decarbonization device 26, and an oxygenation and temperature regulation tank 27, which are connected in a sequential cycle. The effluent treatment subsystem 3 includes a second microfilter 31, a sulfur autotrophic denitrification tank 32, and an SBR reactor cluster, which are connected in a sequential cycle.

[0029] The aquaculture pond cluster 21 includes multiple parallel aquaculture pond groups, each consisting of multiple longitudinally arranged aquaculture pond units 210. Adjacent aquaculture pond groups are equipped with supernatant outlet pipe 211 and sediment outlet pipe 212, with the sediment outlet pipe 212 located directly below the supernatant outlet pipe 211.

[0030] The aquaculture pond unit 210 includes a pond body 213. The bottom of the pond body 213 has a funnel-shaped structure. A water inlet pipe 214 is located at the top of the pond body 213. A pre-filter 215 is located at the center of the bottom of the pond body 213. An aeration device 323 is located in the bottom area of ​​the pond body 213. A filtrate outlet pipe 2151 and a drain pipe 2152 are located at the bottom of the pre-filter 215. A drain pipe shut-off valve 2153 is located on the drain pipe 2152. A feeder 216 is located on the wall of the pond body 213. A vertical flow sedimentation tank 217 is located beside the pond body 213. The filtrate outlet... Water pipe 2151 is connected to vertical flow sedimentator 217. Vertical flow sedimentator 217 has a supernatant outlet branch pipe 2171 at the top and a sediment outlet branch pipe 2172 at the bottom. An overflow box 218 is located on the top area of ​​the outer wall of pool body 213. An overflow port connected to the overflow box 218 is located on the outer wall of pool body 213. An overflow pipe 2181 and a drain pipe 2182 are located inside the overflow box 218. The inlet end of the drain pipe 2182 is located at the bottom of the overflow box 218, and the inlet end of the overflow pipe 2181 is located in the top area inside the overflow box 218. Supernatant outlet branch pipe 2171 and drain pipe 2182 are connected to supernatant outlet main pipe 211. Vent pipe 2152, overflow pipe 2181, and sediment outlet branch pipe 2172 are connected to sediment outlet main pipe 212.

[0031] A sludge tank 34 is located next to the second microfilter 31. The sludge discharge port of the second microfilter 31 is connected to the sludge tank 34. The supernatant outlet pipe of the sludge tank 34 is connected to the sulfur autotrophic denitrification tank 32. The main sludge discharge pipe of the SBR reactor cluster is connected to the sludge tank 34. A screw press 35 is located next to the sludge tank 34. The sludge discharge pipe of the sludge tank 34 is connected to the sludge inlet of the screw press 35. The filtrate pipe of the screw press 35 is connected to the sulfur autotrophic denitrification tank 32. The sludge discharge pipe of the first microfilter 22 is connected to the second microfilter 31. The sludge discharge pipe of the aerated biological filter 24 is connected to the second microfilter 31. The outlet pipe of the constant pressure water supply device 132 is connected to the circulating pump tank 23. A pH adjustment device 231 is installed in the circulating pump tank 23. A second ozone disinfection device 251 and an ultraviolet disinfection device 252 are installed in the disinfection tank 25.

[0032] A pipe gallery is provided in the central area of ​​the sulfur autotrophic denitrification tank 32, which divides the tank into two denitrification zones 321. Each zone 321 has a filter media layer 322 in the middle. The pipe gallery is arranged along the direction of the tank by two gallery walls 323. A first partition wall 324 is horizontally installed above the two walls 323, dividing the pipe gallery into an upper drainage channel area 325 and a lower pipe gallery area 326. A connection to the drainage channel area 325 is provided below the first partition wall 324. The drainage component 327 is connected to the filter bed inlet main pipe 3261 in the pipe gallery area 326. The filter bed inlet main pipe 3261 is arranged along the direction of the pipe gallery area 326. Inlet branch pipes 3262 are arranged at intervals on the filter bed inlet main pipe 3261. Each inlet branch pipe 3262 extends through the gallery wall 323 to the bottom of the filter media layer 322. The inner wall top of the denitrification zone 321 is provided with a return pipe 328. A return pump is provided on the return pipe 328. The return pipe 328 is connected to the filter bed inlet main pipe 3261. Within the drainage trough area 325, two rows of second partition walls 3251 are arranged vertically and symmetrically along the pipe gallery area 326. These two rows of second partition walls 3251 divide the drainage trough area 325 into two filtrate outlet troughs 3252 on either side and a wastewater outlet trough 3253 in the middle. The drainage assembly 327 includes two filtrate outlet main pipes 3271 and one wastewater outlet main pipe 3272, and the filtrate outlet main pipes 3271 and 3272 are connected to the filtrate outlet trough 3252 and the wastewater outlet trough 3253 in the middle. The effluent outlet tank 3253 is correspondingly provided; one or more filtrate outlet branch pipes 3273 are connected between the main filtrate outlet pipe 3271 and the filtrate outlet tank 3252, and one or more sewage outlet branch pipes 3274 are connected between the main sewage outlet pipe 3272 and the sewage outlet tank 3253. A backwash inlet main pipe 3263, matching the denitrification zone 321, is provided in the pipe gallery area 326. The backwash inlet main pipe 3263 is arranged along the direction of the pipe gallery area 326. Multiple backwash inlet branch pipes 3264 are connected to the pipe wall of 263, and the outlet of the backwash inlet branch pipe 3264 is located below the filter media layer 322; an air inlet main pipe 3265 is provided in the pipe gallery area 326, and the air inlet main pipe 3265 is arranged along the direction of the pipe gallery area 3266. Multiple air inlet branch pipes 3266 are provided on the pipe wall of the air inlet main pipe 3265, and the multiple air inlet branch pipes 3266 are evenly spaced below the filter media layer 322, and the pipe walls of the air inlet branch pipes 3266 are evenly spaced. The distribution includes multiple air outlet micropores; valves are provided on the water inlet branch pipe 3262, backwash water inlet branch pipe 3264, air inlet branch pipe 3266, filtrate outlet branch pipe 3273, sewage outlet branch pipe 3274 and return pipe 328; the filter media layer 322 includes a support filter plate 3221 and a single sulfur filter media layer 3222, the side wall of the support filter plate 3221 is fixed on the inner wall of the sulfur autotrophic denitrification tank 32, and the single sulfur filter media layer 3222 is placed above the support filter plate 3221.

[0033] The SBR reactor cluster consists of multiple SBR reactors 33 connected in parallel. Suspended packing material 339 is placed inside each SBR reactor 33. Multiple aerators 331 are located at the bottom of each SBR reactor 33, and multiple main air supply pipes 334 are located at the top of each SBR reactor 33. Each main air supply pipe 334 has multiple branch air supply pipes 3341, and each branch air supply pipe 3341 is connected to one aerator 331. An air pump 332 is located at the air inlet of each main air supply pipe 334. A circulation pump 333 is located beside each SBR reactor 33, and a water suction pipe 33 is installed on the circulation pump 333. 5. The main return water pipe 336 is equipped with multiple return water branch pipes 3361, each of which is connected to an aerator 331; the SBR reactor 33 is equipped with a reactor inlet pipe 337, which is connected to the supernatant outlet pipe of the sulfur autotrophic denitrification tank 32; the SBR reactor 33 is equipped with a decanter 338, which is arranged at the tail of the tank along the width of the tank surface, and the decanter 338 is equipped with an outlet pipe 3381; the gas supply branch pipe 3341, the return water branch pipe 3361, and the inlet pipe 337 are all equipped with valves.

[0034] The following describes the process flow of this system during operation: The freshwater recirculating aquaculture system comprises three sequentially interconnected subsystems: an influent treatment subsystem 1, an aquaculture pond system, and a effluent treatment subsystem 3. This forms a closed-loop, large-scale circulating process consisting of the influent subsystem, the internal small-scale circulation subsystem, and the effluent treatment subsystem. The specific process is as follows: I. Source Water Treatment and Replenishment Process The effluent from the tailwater treatment system can be used as a recycled water source and enter the water storage tank 11. At the same time, the system supports external river water as a supplementary water source, which is transported to the water storage tank through a booster pump.

[0035] Sodium hypochlorite was added to the water storage tank 11 for pretreatment to inhibit the growth of microorganisms and to precipitate some particulate matter.

[0036] The raw water is pumped into the sand filter tank 12 to remove suspended solids, colloids and some organic matter from the water, and the filtrate enters the filtered water tank 13.

[0037] The filtered water tank 13 is equipped with a first ozone disinfection device and a constant pressure water supply device 132 to further remove pathogenic microorganisms and ensure the safety of the replenished water quality.

[0038] After ozone disinfection, the source water is transported to the circulating pump pool 23 by the constant pressure water supply device 132 to achieve stable water replenishment of the system, ensure continuous water supply for aquaculture, and form a large circulation system.

[0039] II. Circulating Water Treatment Process In the aquaculture pond cluster 21, multiple aquaculture pond units 210 are divided into two parts: supernatant and precipitate, through a bottom vertical flow sedimentator 217 and a top overflow box 218. The supernatant enters the first microfilter 22 through the supernatant outlet pipe 211 to remove fine particulate matter; The precipitate enters the second microfilter 31 through the precipitate outlet pipe 212 to treat high concentrations of particulate matter.

[0040] The water filtered by the first microfilter 22 enters the circulating pump pool 23, and the pH of the water is adjusted by the pH adjustment device 231 installed in the pool to meet the requirements of aquaculture water.

[0041] The effluent from the circulating pump tank 23 is pumped into the aerated biological filter tank 24, where suspended packing is added and continuous aeration is carried out to degrade organic matter, ammonia nitrogen and nitrite nitrogen in the water through the biofilm method.

[0042] The effluent from the aerated biological filter 24 enters the disinfection tank 25. Inside the disinfection tank 25, a second ozone disinfection device 251 and an ultraviolet disinfection device 252 are installed sequentially along the water flow direction. The second ozone disinfection device 251 uses high-concentration ozone to oxidize and destroy the cell walls and enzyme systems of pathogenic microorganisms, and simultaneously removes color and odor. The ultraviolet disinfection device 252 further destroys the nucleic acid structure of residual microorganisms by irradiating with ultraviolet light of a specific wavelength, ensuring that pathogens and viruses are completely inactivated, and decomposing the residual ozone from the previous stage to avoid oxidative stress on the cultured organisms.

[0043] The effluent from the disinfection tank 25 enters the decarbonization device 26. The packing material in the decarbonization device 26 can break up and decompose the water, and the blower continuously blows air to remove excess carbon dioxide from the water, while also further eliminating ozone residue.

[0044] The water from the decarbonization device 26 enters the oxygenation and temperature regulation tank 27, where it is efficiently oxygenated by an oxygen cone and the water temperature is regulated by an air source heat pump to ensure that the water returning to the aquaculture pond meets the needs of the aquaculture organisms.

[0045] The effluent from oxygenation and temperature regulation tank 27 flows back to each aquaculture tank unit 210 through pipes, forming an internal small circulation.

[0046] Each aquaculture pond unit 210 is equipped with a nano-ceramic aeration disc at the bottom, which is connected to a liquid oxygen tank. It can independently supply oxygen under power outage or low-density aquaculture conditions, ensuring emergency oxygen supply needs, reducing the operating load of the oxygen cone, and improving system stability and energy efficiency.

[0047] III. Wastewater Treatment Process High-concentration wastewater from the aquaculture pond cluster 21, the first microfilter 22, and the aerated biological filter 24 is collected and then enters the second microfilter 31 to intercept suspended particulate matter.

[0048] The filtrate from the second microfilter 31 enters the sulfur autotrophic denitrification tank 32. The water flows from bottom to top through the elemental sulfur filter media layer 3222 of the sulfur autotrophic denitrification tank 32. Under the action of sulfur autotrophic denitrifying bacteria, the nitrate nitrogen in the effluent is reduced to nitrogen gas, completing the denitrification process. The filter tank is equipped with a backwashing system (air flushing + water flushing) to clean the filter media regularly. The wastewater after cleaning is discharged through the wastewater outlet tank 3253. At this time, the valve on the filtrate outlet branch pipe 3273 is closed to prevent blockage and nitrogen gas accumulation. The top of the filter tank is equipped with a return pipe 3223, which can return part of the effluent to the inlet water main pipe 3211 of the filter tank at the inlet end to adjust the dissolved oxygen concentration of the influent and improve the denitrification efficiency.

[0049] The effluent from the sulfur autotrophic denitrification tank 32 enters the SBR reactor cluster. This device consists of multiple SBR reactors 33 connected in parallel and adopts a four-stage circulation operation mode of "influent-reaction-sedimentation-drainage" to ensure continuous influent and stable effluent of the system.

[0050] The SBR reactor cluster further removes pollutants such as organic matter, ammonia nitrogen, total nitrogen, and total phosphorus from the water, and the effluent quality meets the reuse standards.

[0051] The backwash sludge from the second microfilter 31 and the residual sludge discharged from the SBR reactor cluster enter the sludge tank 34. The supernatant enters the sulfur autotrophic denitrification tank 32. The bottom sludge is transported by a submersible pump to the screw press 35 for dewatering. The sludge cake is transported off-site, and the filtrate is transported to the sulfur autotrophic denitrification tank 32 for further treatment.

[0052] Example 2 like Figure 9 The method for treating water throughout the entire process of freshwater recirculating aquaculture, as shown, is based on any one of the freshwater recirculating aquaculture systems described in claims 1 to 8, and is characterized by comprising the following steps: S1. Source water treatment and constant pressure water replenishment process: External source water or treated wastewater is introduced into the storage tank 11 for storage and pretreatment. Sodium hypochlorite is added to inhibit the growth of microorganisms and precipitate particulate matter. The water from the storage tank 11 is lifted to the sand filter tank 12 for filtration to remove suspended solids, colloids and some organic matter from the water. The filtered water is stored in the filtered water tank 13. After being sterilized and disinfected by the first ozone disinfection device 131, the water is replenished to the circulation pump tank 23 of the aquaculture tank subsystem through the constant pressure water supply device 132 installed therein. S2. Circulating water treatment and internal circulation process: S2.1, Aquaculture wastewater diversion and collection: The wastewater generated by the aquaculture pond unit 210 is collected in diversion. The supernatant collected by the top overflow box 218 and the supernatant collected by the vertical flow sedimentator 217 are merged into the supernatant outlet main pipe 211. The sediment discharged by the bottom pre-filter 215, the sediment collected by the vertical flow sedimentator 217 and the overflow collected by the overflow pipe 2181 are merged into the sediment outlet main pipe 212. S2.2 Physical filtration: The supernatant is sent to the first microfilter 22 for filtration. S2.3 Water quality adjustment: After filtration, the water is sent into the circulating pump pool 23 and the pH adjustment device 231 is used to adjust the acidity and alkalinity of the water. S2.4 Biological purification: The effluent from the circulating pump tank 23 is pumped into the aerated biological filter tank 24, where organic matter, ammonia nitrogen and nitrite nitrogen in the water are degraded using the biofilm method. S2.5 Disinfection treatment: The effluent from the biological filter is introduced into the disinfection tank 25, and the second ozone disinfection device 251 and the ultraviolet disinfection device 252 are used for combined disinfection. S2.6 Decarbonization treatment: The disinfected effluent is sent to the decarbonization device 26, where excess carbon dioxide and residual ozone in the water are removed by aeration. S2.7 Oxygenation, temperature regulation and reflux: The treated water is sent to the oxygenation and temperature regulation tank 27 for dissolved oxygen replenishment and temperature regulation, and then refluxed to each aquaculture tank unit 210 through the water inlet pipe 214. S3. Wastewater Treatment and Resource Reuse Process: High-concentration wastewater from the sediment effluent main pipe 212 is filtered through a second microfilter 31; the filtrate from the second microfilter 31 is fed into a sulfur autotrophic denitrification tank 32 to remove nitrate nitrogen using sulfur autotrophic denitrification; the effluent from the sulfur autotrophic denitrification tank is fed into an SBR reactor cluster for advanced treatment using a sequencing batch reactor (SBR) activated sludge process; the treated effluent from the SBR reactor cluster is transported to a water storage tank 11 as a reclaimed water source.

[0053] In step S3, the filter residue produced by the second microfilter 31 is transported to the sludge tank 34. After concentration in the sludge tank 34, the supernatant is transported to the sulfur autotrophic denitrification tank 32, and the sludge is transported to the screw press 35. After dewatering treatment by the screw press 35, the dewatered filtrate is transported to the sulfur autotrophic denitrification tank 32, and the sludge cake is transported off-site for treatment. The sludge discharged from the SBR reactor cluster is transported to the sludge tank.

[0054] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A full-cycle water treatment system for freshwater recirculating aquaculture, characterized by: The application relates to an aquaculture system, which comprises a water inlet treatment subsystem (1), an aquaculture pool subsystem and a tail water treatment subsystem (3) which are sequentially connected in circulation, the water inlet treatment subsystem (1) comprises a water storage pool (11), a sand filter tank (12) and a filtered water pool (13) which are sequentially connected, the filtered water pool (13) is internally provided with a first ozone sterilization device (131) and a constant pressure water supply device (132) which are sequentially arranged, the aquaculture pool subsystem comprises a plurality of aquaculture pool circulation combinations (2), the aquaculture pool circulation combination (2) comprises an aquaculture pool cluster (21), a first microfilter (22), a circulating pump pool (23), a biological aerated filter (24), a sterilization pool (25), a decarbonization device (26) and an oxygenation and temperature adjustment pool (27) which are sequentially connected in circulation, and the tail water treatment subsystem (3) comprises a second microfilter (31), a sulfur autotrophic denitrification pool (32) and an SBR reaction pool cluster which are sequentially connected.

2. A full process water treatment system for freshwater recirculating aquaculture according to claim 1, characterized in that: The aquaculture pool cluster (21) comprises a plurality of parallel water product aquaculture pool groups which are composed of a plurality of aquaculture pool units (210) arranged in the longitudinal direction, and between adjacent water product aquaculture pool groups, a supernatant outlet main pipe (211) and a precipitate outlet main pipe (212) matched with the supernatant outlet main pipe (211) are arranged, and the precipitate outlet main pipe (212) is arranged directly below the supernatant outlet main pipe (211).

3. A full process water treatment system for freshwater recirculating aquaculture according to claim 2, characterized in that: The aquaculture pool unit (210) comprises a pool body (213), the bottom of the pool body (213) is in a funnel shape, the top of the pool body (213) is provided with a water inlet pipe (214), the center of the bottom of the pool body (213) is provided with a pre-filter (215), the bottom area of the pool body (213) is provided with an aeration device (323), the bottom of the pre-filter (215) is provided with a filtrate outlet pipe (2151) and a vent pipe (2152), the vent pipe (2152) is provided with a vent pipe stop valve (2153), the pool wall of the pool body (213) is provided with a feeder (216), a vertical flow precipitator (217) is arranged beside the pool body (213), the filtrate outlet pipe (2151) is communicated with the vertical flow precipitator (217), the top of the vertical flow precipitator (217) is provided with a supernatant outlet branch pipe (2171), and the bottom of the vertical flow precipitator (217) is provided with a precipitate outlet branch pipe (2172); the top area of the outer wall of the pool body (213) is provided with an overflow box (218), the outer wall of the pool body (213) is provided with an overflow port communicated with the overflow box (218), the overflow box (218) is internally provided with an overflow pipe (2181) and a drain pipe (2182), the water inlet end of the drain pipe (2182) is arranged at the bottom of the overflow box (218), and the water inlet end of the overflow pipe (2181) is arranged at the top area in the overflow box (218).

4. A full process water treatment system for freshwater recirculating aquaculture according to claim 3, characterized in that: The supernatant outlet branch pipe (2171) and the drain pipe (2182) are communicated with the supernatant outlet main pipe (211), and the vent pipe (2152), the overflow pipe (2181) and the precipitate outlet branch pipe (2172) are communicated with the precipitate outlet main pipe (212).

5. The full-cycle water treatment system for freshwater recirculating aquaculture of claim 1, wherein: The second microfilter (31) is provided with a sludge tank (34), the slag outlet of the second microfilter (31) is communicated with the sludge tank (34), and the supernatant outlet pipe of the sludge tank (34) is communicated with the sulfur autotrophic denitrification tank (32); the total sludge discharge pipe of the SBR reaction tank cluster is communicated with the sludge tank (34); the sludge tank (34) is provided with a spiral machine (35), the sludge discharge pipe of the sludge tank (34) is communicated with the sludge inlet of the spiral machine (35), and the filtrate pipe of the spiral machine (35) is communicated with the sulfur autotrophic denitrification tank (32); the slag outlet pipe of the first microfilter (22) is communicated with the second microfilter (31), the sludge outlet pipe of the biological aerated filter (24) is communicated with the second microfilter (31), and the water outlet pipe of the constant pressure water supply device (132) is communicated with the circulating pump tank (23); the circulating pump tank (23) is provided with a pH adjusting device (231); the disinfection tank (25) is provided with a second ozone disinfection device (251) and an ultraviolet disinfection device (252).

6. The full-cycle water treatment system for freshwater recirculating aquaculture of claim 1, wherein: The middle part of the sulfur autotrophic denitrification tank (32) is provided with a pipe gallery, the pipe gallery divides the sulfur autotrophic denitrification tank (32) into two denitrification zones (321), and the middle part of each denitrification zone (321) is provided with a filter material layer (322); the pipe gallery is arranged along the running direction of the sulfur autotrophic denitrification tank by two gallery walls (323), the upper part of the two gallery walls (323) is provided with a first partition wall (324) horizontally, the first partition wall (324) divides the pipe gallery into an upper drainage groove area (325) and a lower pipe gallery area (326), a drainage assembly (327) is arranged below the first partition wall (324) and communicated with the drainage groove area (325), a filter tank water inlet main pipe (3261) is arranged in the pipe gallery area (326) and along the running direction of the pipe gallery area (326), water inlet branch pipes (3262) are arranged on the filter tank water inlet main pipe (3261) at intervals, each water inlet branch pipe (3262) extends to below the filter material layer (322) through the gallery wall (323), and a reflux pipe (328) is arranged on the top of the inner wall of each denitrification zone (321), a reflux pump is arranged on the reflux pipe (328), and the reflux pipe (328) is communicated with the filter tank water inlet main pipe (3261).

7. A full-cycle water treatment system for freshwater recirculating aquaculture according to claim 6, characterized in that: The drainage groove area (325) is arranged along the pipe gallery area (326) and is vertically and symmetrically provided with two rows of second partition walls (3251), which divide the drainage groove area (325) into filtrate outlet grooves (3252) on both sides and a sewage outlet groove (3253) in the middle; the drainage assembly (327) comprises two filtrate outlet main pipes (3271) and one sewage outlet main pipe (3272), and the filtrate outlet main pipes (3271) and the sewage outlet main pipe (3272) are arranged correspondingly with the filtrate outlet grooves (3252) and the sewage outlet groove (3253); one or more filtrate outlet branch pipes (3273) are communicated between the filtrate outlet main pipes (3271) and the filtrate outlet grooves (3252), and one or more sewage outlet branch pipes (3274) are communicated between the sewage outlet main pipe (3272) and the sewage outlet groove (3253); the pipe gallery area (326) is provided with a backwashing water inlet main pipe (3263) matched with the denitrification area (321), the backwashing water inlet main pipe (3263) is arranged along the direction of the pipe gallery area (326), and the pipe wall of the backwashing water inlet main pipe (3263) is communicated with a plurality of backwashing water inlet branch pipes (3264), and the water outlet of the backwashing water inlet branch pipe (3264) is arranged below the filter material layer (322); the pipe gallery area (326) is provided with an air inlet main pipe (3265), the air inlet main pipe (3265) is arranged along the direction of the pipe gallery area (326), the pipe wall of the air inlet main pipe (3265) is provided with a plurality of air inlet branch pipes (3266), and the plurality of air inlet branch pipes (3266) are uniformly and spacedly arranged below the filter material layer (322), and the pipe wall of the air inlet branch pipe (3266) is uniformly provided with a plurality of air outlet micropores; the water inlet branch pipe (3262), the backwashing water inlet branch pipe (3264), the air inlet branch pipe (3266), the filtrate outlet branch pipe (3273), the sewage outlet branch pipe (3274) and the reflux pipe (328) are all provided with valves; the filter material layer (322) comprises a supporting filter plate (3221) and a single sulfur filter material layer (3222), the side wall of the supporting filter plate (3221) is fixed on the inner wall of the sulfur autotrophic denitrification tank (32), and the single sulfur filter material layer (3222) is placed above the supporting filter plate (3221).

8. The full-cycle water treatment system for freshwater recirculating aquaculture of claim 1, wherein: The SBR reaction pool cluster is composed of multiple SBR reaction pools (33) in parallel, the SBR reaction pool (33) is provided with suspended filler (339), the bottom of the SBR reaction pool (33) is provided with multiple aerators (331), the top of the SBR reaction pool (33) is provided with multiple gas conveying main pipes (334), each gas conveying main pipe (334) is provided with multiple gas conveying branch pipes (3341), each gas conveying branch pipe (3341) is communicated with an aerator (331), the air inlet end of the gas conveying main pipe (334) is provided with an air pump (332), the circulating pump (333) is provided beside the SBR reaction pool (33), the circulating pump (333) is provided with a water suction pipe (335) and a water return main pipe (336), the water return pipe is provided with multiple water return branch pipes (3361), each water return branch pipe (3361) is communicated with an aerator (331); The SBR reaction pool (33) is provided with a reaction pool water inlet pipe (337), the reaction pool water inlet pipe (337) is communicated with the supernatant outlet pipe of the sulfur autotrophic denitrification tank (32); The SBR reaction pool (33) is provided with a water decanter (338), the water decanter (338) is arranged at the tail of the pool along the width direction of the pool surface, the water decanter (338) is provided with a water outlet pipe (3381); The gas conveying branch pipe (3341), the water return branch pipe (3361) and the water inlet pipe (337) are all provided with valves.

9. A method for water treatment in a full-cycle freshwater recirculating aquaculture system, the method being implemented based on the system for water treatment in a full-cycle freshwater recirculating aquaculture system according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: S1, source water treatment and constant pressure water supply process: introducing external source water or reused treated tail water into the water storage tank (11) for storage and pretreatment, adding sodium hypochlorite to inhibit the growth of microorganisms and precipitate particulate matter, raising the water outlet of the water storage tank (11) to the sand filter tank (12) for filtration to remove suspended solids, colloids and part of organic matter in the water, storing the filtered water in the filtered water tank (13), sterilizing and disinfecting by the first ozone disinfection device (131), and providing constant flow and pressure water supply to the circulating pump tank (23) of the culture tank subsystem by the constant pressure water supply device (132) arranged therein; S2, circulating water treatment and internal circulation process: S2.1, breeding wastewater diversion collection: the wastewater generated by the culture tank unit (210) is diverted and collected, the supernatant collected by the top overflow box (218) and the supernatant collected by the vertical flow sedimentation device (28) are merged into the supernatant outlet main pipe (211), the sediment collected by the bottom pre-filter (215), the sediment collected by the vertical flow sedimentation device (28) and the overflow liquid collected by the overflow pipe (2181) are merged into the sediment outlet main pipe (212); S2.2, physical filtration: the supernatant is delivered to the first microfilter (22) for filtration; S2.3, water quality adjustment: the filtered water is sent to the circulating pump tank (23) and the pH adjusting device (231) is used to adjust the water pH value; S2.4, biological purification: the water outlet of the circulating pump tank (23) is pumped into the biological aerated filter (24) to degrade organic matter, ammonia nitrogen and nitrite nitrogen in the water by using the biofilm method; S2.5, disinfection treatment: the effluent of the biofilter is introduced into a disinfection tank (25), and a second ozone disinfection device (251) and an ultraviolet disinfection device (252) are used for combined disinfection; S2.6, decarburization treatment: the effluent after disinfection is sent to a decarburization device (26), and excess carbon dioxide and residual ozone in the water body are removed by air blowing aeration; S2.7, oxygenation temperature adjustment and reflux: the treated water is sent to an oxygenation temperature adjustment tank (27) for oxygen supplement and temperature adjustment, and is refluxed to each aquaculture tank unit (210) through a water inlet pipe (214); S3, tail water treatment and resource recycling process: high-concentration sewage from the sediment effluent main pipe (212) is filtered through a second microfilter (31); the filtrate of the second microfilter (31) is introduced into a sulfur autotrophic denitrification tank (32), and sulfur autotrophic denitrification is used to remove nitrate nitrogen; the effluent of the sulfur autotrophic denitrification tank is introduced into an SBR reaction tank cluster, and is subjected to deep treatment by a sequencing batch reactor (SBR) activated sludge method; the treated effluent of the SBR reaction tank cluster is delivered to a water storage tank (11) as a recycled water source.

10. The full process water treatment method for freshwater recirculating aquaculture according to claim 9, characterized in that: In the step S3, the filter residue generated by the second microfilter (31) is delivered to a sludge tank (34), and after concentration in the sludge tank (34), the supernatant is delivered to the sulfur autotrophic denitrification tank (32), and the sludge is delivered to a decanter (35) for dewatering treatment, and the dewatered filtrate is delivered to the sulfur autotrophic denitrification tank (32), and the mud cake is transported out for treatment; the sludge discharged from the SBR reaction tank cluster is delivered to the sludge tank.

Images