Tail water treatment method

Abstract

The application discloses a tail water treatment method applied to the field of soft-shelled turtle breeding, and the tail water treatment method comprises the following steps: filtering tail water generated in a breeding greenhouse and a breeding pond to obtain tail water filtered for the first time in the breeding greenhouse and tail water filtered for the first time in the breeding pond; performing anaerobic-anoxic-oxygenic treatment on the tail water filtered for the first time in the breeding greenhouse by biological denitrification to obtain tail water subjected to denitrification treatment; sequentially discharging the tail water subjected to denitrification treatment and the tail water filtered for the first time in the breeding pond into a primary sedimentation tank, a secondary oxidation tank and a tertiary biological tank to obtain treated tail water; and detecting the treated tail water, discharging the detected qualified tail water into a wetland for recycling or discharging the detected qualified tail water. The technical scheme of the application effectively inhibits the reproduction of filamentous bacteria in the breeding water body, overcomes sludge bulking, is beneficial to sludge-water separation, improves the water quality of the breeding water body, guarantees the quality and safety of aquatic products, and realizes zero-pollution discharge of the breeding tail water.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a wastewater treatment method. Background Technology

[0002] Factory farming of turtles and tortoises is an emerging and distinctive aquaculture industry in my country. However, the wastewater generated during the farming process often harms the water bodies and ecological environment around the farms, seriously restricting the sustainable development of the aquaculture industry. There is an urgent need to solve the problem of wastewater treatment technology in turtle and tortoise farming. Summary of the Invention

[0003] This invention provides a wastewater treatment method that can improve the water quality of aquaculture water bodies, ensure the quality and safety of aquatic products, and achieve zero pollution discharge of aquaculture wastewater.

[0004] This invention provides a wastewater treatment method applicable to turtle and tortoise aquaculture. The wastewater treatment method includes: filtering wastewater generated in aquaculture greenhouses and ponds to obtain primary filtered wastewater from the aquaculture greenhouses and ponds; subjecting the primary filtered wastewater from the aquaculture greenhouses to anaerobic-anoxic-aerobic biological denitrification treatment to obtain denitrified wastewater; sequentially discharging the denitrified wastewater and the primary filtered wastewater from the ponds into a primary sedimentation tank, a secondary oxidation tank, and a tertiary biological treatment tank to obtain treated wastewater; testing the treated wastewater, and discharging wastewater that meets the standards into a wetland for recycling or discharging it into the wild.

[0005] This invention employs a phosphorus and nitrogen removal process that, under anaerobic, anoxic, and aerobic operating conditions, effectively inhibits the proliferation of filamentous bacteria in aquaculture water, overcomes sludge bulking, facilitates sludge-water separation, improves water quality, ensures the safety and quality of aquatic products, and achieves zero-pollution discharge of aquaculture wastewater. Because the anaerobic, anoxic, and aerobic zones are strictly separated, it promotes the growth and reproduction of different microbial communities, resulting in superior nitrogen and phosphorus removal effects.

[0006] According to the aforementioned embodiments of the present invention, the effluent from the initial filtration of the aquaculture greenhouse undergoes anaerobic-anoxic-aerobic biological denitrification treatment to obtain denitrified effluent, comprising: discharging the effluent from the initial filtration of the aquaculture greenhouse into a regulating sedimentation tank; retaining some organic matter in the effluent after sedimentation in the regulating sedimentation tank; the upper layer of effluent from the initial filtration of the aquaculture greenhouse entering a biological fermentation tank; and the remaining effluent entering a flotation tank; adding water purification materials to the flotation tank to obtain effluent after flocculation; sending the upper clear liquid of the flocculated effluent to a fishpond; and sequentially sending the lower flocculated sediment to a sludge tank and a biological fermentation tank; aerating and stirring the fishpond to obtain oxygenated effluent; and sending the oxygenated effluent to an aerobic tank; and aerating the aerobic tank to obtain denitrified effluent.

[0007] According to the aforementioned embodiments of the present invention, water purification materials are added to the flotation tank to obtain effluent after flocculation reaction. The upper clear liquid of the effluent after flocculation reaction is sent to a fishpond, and the lower flocculated sediment is sequentially sent to a sludge tank and a biological fermentation tank. The process includes: the lower flocculated sediment is sent to the sludge tank and enters a sludge dewatering treatment system. The sludge dewatering treatment system adopts a filter press. The upper clear liquid in the sludge tank is filtered and then transported out of the sludge tank, leaving sludge sediment in the sludge tank; the sludge sediment is then sent to the biological fermentation tank, and after water control, the sludge sediment is transported out of the biological fermentation tank to obtain fertilizer.

[0008] According to the aforementioned embodiments of the present invention, aeration treatment in an aerobic tank to obtain denitrified effluent includes: aerating the oxygenated effluent by laying aeration discs or microporous aeration pipes in the aerobic tank to obtain aerated effluent; the supernatant in the aerobic tank flows into the sludge tank via a return pump; and the sediment in the aerobic tank is sequentially discharged into a primary sedimentation tank, a secondary oxidation tank, and a tertiary biological tank.

[0009] According to the aforementioned embodiments of the present invention, the effluent after denitrification treatment is sequentially discharged into a primary sedimentation tank, a secondary oxidation tank, and a tertiary biological tank to obtain the treated effluent, which includes: the sediment in the aerobic tank enters the primary sedimentation tank through a pipe channel; the liquid in the primary sedimentation tank enters the secondary oxidation tank through an overflow dam; the liquid in the secondary oxidation tank flows into the tertiary biological tank through a subsurface dam; and the tertiary biological tank is equipped with a filter membrane, aquatic plants, flocculants, and filter-feeding fish.

[0010] According to the aforementioned embodiments of the present invention, the three-stage biological pond is equipped with a filter membrane, aquatic plants, flocculants, and filter-feeding fish, including: planting submerged plants and floating plants at the bottom of the three-stage biological pond, planting emergent plants around the three-stage biological pond, and arranging an oxygenation spray system in the middle of the three-stage biological pond; and installing an S-shaped filter membrane in the three-stage biological pond.

[0011] According to the foregoing embodiments of the present invention, filtering the wastewater generated in the aquaculture greenhouse and the aquaculture pond to obtain the wastewater after initial filtration of the aquaculture greenhouse and the wastewater after initial filtration of the aquaculture pond includes: connecting the aquaculture greenhouse and the aquaculture pond in series, collecting the wastewater in the aquaculture greenhouse to a pretreatment tank through pipes and channels; filtering the wastewater in the aquaculture pond through a filtration structure in the pretreatment tank to obtain the wastewater after initial filtration of the aquaculture greenhouse and the wastewater after initial filtration of the aquaculture pond.

[0012] According to the aforementioned embodiments of the present invention, collecting the wastewater from the aquaculture greenhouse to the pretreatment pond via pipes and channels includes: planting slope protection and water purification plants in the pipes and channels; planting aquatic plants or hanging biological fillers such as brushes in the original drainage ditches of the aquaculture pond, and installing aeration discs; the filtration structure includes: a hollow brick structure, the hollow brick structure is filled with a porous adsorption medium, and the direction of the brick holes in the hollow brick structure is consistent with the direction of the wastewater flow.

[0013] According to the aforementioned embodiments of the present invention, the process of testing the treated effluent and discharging the qualified effluent into a wetland for recycling or discharging the qualified effluent includes: filling the cement pool of the wetland with polymer materials of different particle sizes, planting emergent plants on the surface of the wetland to obtain effluent with filtered suspended solids and removed nitrogen, phosphorus and other elements; conducting a compliance test on the effluent with filtered suspended solids and removed nitrogen, phosphorus and other elements, and discharging a portion of the qualified effluent to the outside; aerating and oxygenating another portion of the qualified effluent to obtain qualified effluent after aeration and oxygenation; and discharging the qualified effluent after aeration and oxygenation into an aquaculture pond to achieve recycling. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0015] Figure 1 This is a schematic flowchart of an embodiment of the wastewater treatment method of the present invention;

[0016] Figure 2 This is a schematic diagram of the process of biological denitrification anaerobic-anoxic-aerobic treatment to obtain denitrified effluent in one embodiment of the wastewater treatment method of the present invention.

[0017] Figure 3 This is a schematic diagram of the process of sending the upper clear liquid of the effluent after flocculation reaction into a fish pond and the lower flocculated sediment into a sludge tank and a biological fermentation tank in sequence, as an embodiment of the effluent treatment method of the present invention.

[0018] Figure 4 This is a schematic diagram of a process for aeration treatment in an aerobic tank to obtain denitrified effluent, as an embodiment of the effluent treatment method of the present invention.

[0019] Figure 5 This is a schematic diagram of the process of treating wastewater in an embodiment of the present invention, in which the wastewater after denitrification is sequentially discharged into a primary sedimentation tank, a secondary oxidation tank and a tertiary biological tank to obtain the treated wastewater.

[0020] Figure 6 This is a schematic diagram illustrating the process of filtering wastewater generated in aquaculture greenhouses and aquaculture ponds to obtain wastewater after initial filtration in the aquaculture greenhouses and aquaculture ponds, as an embodiment of the wastewater treatment method of the present invention.

[0021] Figure 7 This is a schematic diagram illustrating the process of detecting treated wastewater and discharging treated wastewater that meets the standards into a wetland for recycling or discharging wastewater that meets the standards, as part of an embodiment of the wastewater treatment method of the present invention.

[0022] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0025] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, the user should consider such a combination of technical solutions to be non-existent and not within the scope of protection claimed by this invention.

[0026] Factory farming of turtles and tortoises is an emerging and distinctive aquaculture industry in my country. However, it lacks relatively reasonable and unified regulatory standards and industry-wide operating procedures. Typically, during winter, farmers use sawdust, honeycomb briquettes, and coal as fuel for greenhouse turtle and tortoise farming. However, this smoldering method results in incomplete combustion, producing high concentrations of smoke and dust, severely hindering the sustainable development of the aquaculture industry. Wastewater generated during turtle and tortoise farming also often harms the surrounding water bodies and ecological environment. Currently, the main methods for treating wastewater from turtle and tortoise farming involve a combination of ecological ditches, ecological channels, and artificial wetlands, as well as anaerobic biogas fermentation technology. However, these methods generally suffer from poor stability, poor operability, and difficulty in meeting effluent quality standards. Furthermore, industrial wastewater treatment methods are prohibitively expensive and require large investments, making them unaffordable for farms. Therefore, there is an urgent need to solve the problem of wastewater treatment technology for turtle and tortoise farming.

[0027] This invention provides a wastewater treatment method that can be applied to turtle and tortoise farming. It can improve the water quality of aquaculture water, ensure the quality and safety of aquatic products, and achieve zero pollution discharge of aquaculture wastewater.

[0028] Figure 1 This is a schematic flowchart of an embodiment of the wastewater treatment method of the present invention, which includes steps S110 to S140.

[0029] In step S110, the wastewater generated in the aquaculture greenhouse and the aquaculture pond is filtered to obtain the wastewater after the first filtration in the aquaculture greenhouse and the wastewater after the first filtration in the aquaculture pond.

[0030] Figure 6 This is a schematic diagram of a process for filtering wastewater generated in a breeding greenhouse and a breeding pond to obtain wastewater after initial filtration in the breeding greenhouse and wastewater after initial filtration in the breeding pond, according to an embodiment of the wastewater treatment method of the present invention. Step S110 may include steps S111 to S112.

[0031] In step S111, the aquaculture greenhouse and the aquaculture pond are connected in series, and the wastewater from the aquaculture greenhouse is collected to the pretreatment tank through pipes. In step S112, the wastewater from the aquaculture pond is filtered through a filtration structure in the pretreatment tank to obtain the wastewater from the aquaculture greenhouse after initial filtration and the wastewater from the aquaculture pond after initial filtration.

[0032] In this embodiment of the invention, slope protection and water purification plants are planted in the pipes and channels, and aquatic plants or biological fillers such as hanging brushes are planted in the original drainage ditches of the aquaculture ponds, and aeration discs are installed; the filter structure includes: a hollow brick structure, the hollow brick structure is filled with a porous adsorption medium, and the direction of the brick holes of the hollow brick structure is consistent with the direction of the tailwater flow.

[0033] In this embodiment of the invention, the plants planted in the pipes for slope protection and water purification include Vallisneria natans, Hydrilla verticillata, water lilies, irises, wild rice, and lotus. Aquatic plants or biological fillers such as hanging brushes are planted in the existing drainage ditches of the aquaculture ponds to increase the oxidation of pollutants in the water and to impair suspended solids in the water.

[0034] In this embodiment of the invention, the filter structure employs a two-row hollow brick structure. The interval between the two rows of hollow bricks is no less than 2 meters. The interior of the two rows of hollow bricks is filled with porous adsorption media such as ceramic beads or volcanic rock to maximize the treatment of organic pollutants. Plants are then planted on the internal filling media to enhance the landscaping effect.

[0035] In this embodiment of the invention, the pretreatment tank includes: a bar screen well, an equalization tank, a hydrolysis acidification tank, a contact oxidation tank, a disinfection tank, etc., forming four functional zones for sedimentation, aeration, compound microbial inoculum, and purification, so as to improve the overall purification effect.

[0036] In step S120, the wastewater after the initial filtration in the aquaculture greenhouse is subjected to anaerobic-anoxic-aerobic biological denitrification treatment to obtain denitrified wastewater.

[0037] Figure 2 This is a schematic diagram of a process for biological denitrification anaerobic-anoxic-aerobic treatment to obtain denitrified effluent in one embodiment of the wastewater treatment method of the present invention. Step S120 may include steps S121 to S124.

[0038] In step S121, the effluent from the initial filtration of the aquaculture greenhouse is discharged into the regulating sedimentation tank. Some of the organic matter in the effluent from the initial filtration of the aquaculture greenhouse is retained in the regulating sedimentation tank after sedimentation. The upper layer of effluent from the initial filtration of the aquaculture greenhouse enters the biological fermentation tank, and the remaining effluent enters the air flotation tank.

[0039] In this embodiment of the invention, the sedimentation tank is equipped with alternating main and auxiliary drive pumps. The effluent from the initial filtration of the aquaculture greenhouse entering the sedimentation tank rises to become upper effluent under the alternating drive of the main and auxiliary pumps and then enters the biological fermentation tank. The alternating operation of the main and auxiliary pumps effectively addresses the needs of high-load water bodies or other unforeseen circumstances. The main and auxiliary pumps are liftable, non-clogging submersible sewage pumps, which are highly efficient, energy-efficient, have a streamlined structure, are easy to maintain, require low investment, and produce low noise.

[0040] In step S122, water purification material is added to the flotation tank to obtain effluent after flocculation reaction. The upper clear liquid of the effluent after flocculation reaction is sent to the fish pond, and the lower flocculated sediment is sent to the sludge tank and the biological fermentation tank in sequence.

[0041] Figure 3This is a schematic diagram of the process of sending the upper clear liquid of the effluent after flocculation reaction into a fish pond and the lower flocculated sediment into a sludge tank and a biological fermentation tank in sequence, according to an embodiment of the effluent treatment method of the present invention. Step S122 may include: steps S1221 to S1222.

[0042] In step S1221, the lower layer of flocculated sediment is sent into the sludge tank and enters the sludge dewatering treatment system. The sludge dewatering treatment system uses a filter press. The clear liquid above the sludge tank is filtered and then transported out of the sludge tank, leaving the remaining sludge sediment in the sludge tank.

[0043] In step S1222, the sludge sediment is sent into the biological fermentation tank, and after the sludge sediment is drained, it is transported out of the biological fermentation tank to obtain fertilizer.

[0044] In step S123, oxygenation and stirring are carried out in the fishpond to obtain oxygenated tailwater, which is then sent to an aerobic tank.

[0045] In step S124, aeration is performed in the aerobic tank to obtain denitrified effluent.

[0046] Figure 4 This is a schematic diagram of a process for aeration treatment in an aerobic tank to obtain denitrified effluent, according to an embodiment of the effluent treatment method of the present invention. Step S124 may include steps S1241 to S1243.

[0047] In step S1241, aeration discs or microporous aeration pipes are laid in the aerobic tank to aerate the oxygenated effluent, thereby obtaining aerated effluent.

[0048] In step S1242, the supernatant in the aerobic tank flows into the sludge tank via a return pump.

[0049] In step S1243, the sediment in the aerobic tank is sequentially discharged into the primary sedimentation tank, the secondary oxidation tank, and the tertiary biological tank.

[0050] In this embodiment of the invention, an aerator is installed in the aerobic tank to increase aeration, thus forming an aerobic tank. The large number of activated sludge microorganisms that proliferate in the aerobic tank can degrade and adsorb organic pollutants in the water, thereby purifying the water quality. The supernatant in the aerobic tank flows into the sludge tank via a return pump, where it further settles before entering the clear water zone. It can then flow into a connecting channel, where it is further treated by plant adsorption zones and filter dams, achieving the goal of treatment for discharge or agricultural reuse.

[0051] In step S130, the denitrified wastewater and the wastewater from the initial filtration of the aquaculture pond are sequentially discharged into a primary sedimentation tank, a secondary oxidation tank, and a tertiary biological tank to obtain treated wastewater.

[0052] Figure 5 The following is a schematic diagram of the process of treating wastewater in an embodiment of the present invention, in which the wastewater after denitrification is sequentially discharged into a primary sedimentation tank, a secondary oxidation tank and a tertiary biological tank to obtain the treated wastewater. Step S130 may include steps S131 to S132.

[0053] In step S131, the sediment in the aerobic tank enters the primary sedimentation tank through pipes, and the liquid in the primary sedimentation tank enters the secondary oxidation tank through an overflow dam.

[0054] In step S132, the liquid in the secondary oxidation tank flows into the tertiary biological tank through the subsurface dam. The tertiary biological tank is equipped with a filter membrane, aquatic plants, flocculants, and filter-feeding fish.

[0055] In this embodiment of the invention, the three-stage biological tank is equipped with a filter membrane, aquatic plants, flocculants, and filter-feeding fish, including: planting submerged plants and floating plants at the bottom of the three-stage biological tank, planting emergent plants around the three-stage biological tank, and arranging an oxygenation spray system in the middle of the three-stage biological tank; and installing an S-shaped filter membrane in the three-stage biological tank.

[0056] In this embodiment of the invention, aquatic organisms at different trophic levels are primarily utilized to remove pollutants from the water to the greatest extent possible, while simultaneously increasing dissolved oxygen levels. The bottom of the three-stage biological tank is planted with submerged plants (such as *Vallisneria natans*, *Hydrilla verticillata*, and *Elodea nuttallii*), floating plants (such as lotus, water lilies, and *Gorgon fruit*), and emergent plants (such as water chestnuts, canna lilies, and irises) around the perimeter. An aeration spray system is installed in the center. A certain amount of shrimp, silver carp, bighead carp, and snails can be stocked in the three-stage biological tank to convert nutrients such as nitrogen and phosphorus into high-quality aquatic products. By installing an S-shaped filter screen with attached biofilm in the three-stage biological tank, the water flow path distance is increased, improving the purification effect.

[0057] In step S140, the treated effluent is tested, and the effluent that meets the standards is either discharged into the wetland for recycling or discharged.

[0058] Figure 7 This is a schematic diagram of a process for detecting treated wastewater and discharging treated wastewater that meets the standards into a wetland for recycling or discharging treated wastewater that meets the standards, according to an embodiment of the wastewater treatment method of the present invention. Step S140 may include steps S141 to S144.

[0059] In step S141, the cement pool of the wetland is filled with polymer materials of different particle sizes, and emergent plants are planted on the surface of the wetland to obtain tailwater that has been filtered of suspended solids and removed from elements such as nitrogen and phosphorus.

[0060] In step S142, the effluent that has been filtered of suspended solids and had nitrogen, phosphorus and other elements removed is tested for compliance, and a portion of the qualified effluent is discharged to the outside.

[0061] In step S143, another portion of the qualified effluent is aerated and oxygenated to obtain compliant effluent after aeration and oxygenation.

[0062] In step S144, the qualified effluent after aeration and oxygenation is discharged into the aquaculture pond to achieve recycling.

[0063] In this embodiment of the invention, the wetland is mainly used for filtering suspended solids and removing elements such as nitrogen and phosphorus. In this embodiment, a cement pool is filled with polymer materials such as pebbles or magnetic beads of different particle sizes to filter suspended solids. Emergent plants, such as canna lilies, irises, and thaliana, are planted on the wetland surface, with a planting area of ​​not less than 1 / 50 of the aquaculture water surface.

[0064] This invention employs a phosphorus and nitrogen removal process that, under anaerobic, anoxic, and aerobic operating conditions, effectively inhibits the proliferation of filamentous bacteria in aquaculture water, overcomes sludge bulking, facilitates sludge-water separation, improves water quality, ensures the safety and quality of aquatic products, and achieves zero-pollution discharge of aquaculture wastewater. Because the anaerobic, anoxic, and aerobic zones are strictly separated, it promotes the growth and reproduction of different microbial communities, resulting in superior nitrogen and phosphorus removal effects.

[0065] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for treating wastewater, characterized in that, The wastewater treatment method is applied in the field of turtle and tortoise farming, and the wastewater treatment method includes: Step S110: Filter the wastewater generated in the aquaculture greenhouse and aquaculture pond to obtain the wastewater after the first filtration in the aquaculture greenhouse and the wastewater after the first filtration in the aquaculture pond. Step S120: The effluent from the initial filtration of the aquaculture greenhouse is subjected to anaerobic-anoxic-aerobic biological denitrification treatment to obtain denitrified effluent, including: The effluent from the initial filtration of the aquaculture greenhouse is discharged into the regulating sedimentation tank. Some of the organic matter in the effluent from the initial filtration of the aquaculture greenhouse settles and remains in the regulating sedimentation tank. The upper layer of effluent from the initial filtration of the aquaculture greenhouse enters the biological fermentation tank, and the remaining effluent enters the air flotation tank. The regulating sedimentation tank is equipped with a main drive water pump and an auxiliary drive water pump that operate alternately. Under the alternating drive of the main drive water pump and the auxiliary drive water pump, the effluent from the initial filtration of the aquaculture greenhouse entering the regulating sedimentation tank rises to become the upper layer of effluent and enters the biological fermentation tank. Water purification materials are added to the flotation tank to obtain effluent after flocculation. The upper clear liquid of the effluent after flocculation is sent to a fishpond, and the lower flocculated sediment is sent to a sludge tank and then to a sludge dewatering system. The sludge dewatering system uses a filter press. The upper clear liquid in the sludge tank is filtered and then transported out of the sludge tank. The remaining sludge sediment in the sludge tank is sent to the biological fermentation tank. After the sludge sediment is dewatered, it is transported out of the biological fermentation tank to obtain fertilizer. The fishpond is aerated and stirred to obtain aerated tailwater, which is then sent to an aerobic tank. By laying aeration discs or microporous aeration pipes in the aerobic tank, the oxygenated effluent is aerated and oxygenated to obtain denitrified effluent. The supernatant in the aerobic tank flows into the sludge tank via a return pump. Step S130: The effluent after denitrification treatment and the effluent after primary filtration in the aquaculture pond are sequentially discharged into a primary sedimentation tank, a secondary oxidation tank, and a tertiary biological tank, including: the sediment in the aerobic tank enters the primary sedimentation tank through a pipe channel, the liquid in the primary sedimentation tank enters the secondary oxidation tank through an overflow dam, and the liquid in the secondary oxidation tank flows into the tertiary biological tank through a subsurface dam to obtain treated effluent; Step S140: Detect the treated effluent and discharge the effluent that meets the test standards.

2. The wastewater treatment method as described in claim 1, characterized in that, The three-stage biological pool is equipped with a filter membrane, aquatic plants, flocculants, and filter-feeding fish.

3. The wastewater treatment method as described in claim 2, characterized in that, The three-stage biological tank is equipped with a filter membrane, aquatic plants, flocculants, and filter-feeding fish, including: Submerged plants are planted at the bottom of the three-stage biological pool, emergent plants are planted around the three-stage biological pool, and an oxygenation spray system is installed in the middle of the three-stage biological pool. An S-shaped filter screen with attached biofilm is installed in the three-stage biological tank.

4. The wastewater treatment method as described in claim 1, characterized in that, The process of testing the treated effluent and discharging the effluent that meets the testing standards includes: The treated effluent is treated by wetland, in which the cement pool of the wetland is filled with polymer materials of different particle sizes, and emergent plants are planted on the surface of the wetland to obtain effluent that has been filtered of suspended solids and removed of nitrogen and phosphorus elements. The effluent that has been filtered of suspended solids and had nitrogen and phosphorus removed is subjected to compliance testing, and a portion of the qualified effluent is discharged to the outside. Another part of the qualified effluent was aerated and oxygenated to obtain qualified effluent after aeration and oxygenation. The treated wastewater, after aeration and oxygenation, is discharged into the aquaculture pond for recycling.

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