Mariculture ecological tail water treatment system and treatment method

Abstract

The application discloses a mariculture ecological tail water treatment system and treatment method, and belongs to the field of ecological treatment of aquaculture wastewater. The system comprises a wastewater collection area, an ecological sedimentation area, a emergent plant purification area, a floating leaf plant purification area, a benthic organism collaborative purification area and a water quality conservation and backflow area connected in sequence. The application uses the sedimentation area to settle solid matters; uses salt-tolerant emergent plants and floating leaf plants to adsorb nitrogen and phosphorus; uses modified porous biochar carriers in the benthic organism collaborative area to strengthen salt-tolerant microbial biofilm, deeply degrade ammonia nitrogen and nitrite, and implement passive heat preservation through a light-transmitting heat preservation shed; and uses a multi-parameter water quality monitoring assembly to collect water quality parameters in real time and feed back to a central PLC control unit, so as to locally supplement oxygen through self-adaptive linkage of a micro-nano aeration device, or link control valves to send non-standard water bodies back to front-end closed-loop secondary purification through a reverse backflow channel. The application realizes low-cost, intelligent and highly adaptive closed-loop ecological treatment of mariculture tail water.

Description

Technical Field

[0001] This invention belongs to the field of marine aquaculture and water treatment technology, specifically relating to a marine aquaculture ecological wastewater treatment system and treatment method. Background Technology

[0002] With the continuous development of high-density and large-scale marine aquaculture, a large amount of aquaculture wastewater is constantly generated during the aquaculture process. Since aquaculture wastewater contains a large amount of farmed animal excrement, leftover feed, nitrogen and phosphorus nutrients, harmful bacteria and suspended impurities, if this wastewater is discharged directly, it will easily cause eutrophication of nearshore waters and even trigger red tide disasters, causing serious damage to the marine ecological environment.

[0003] Currently, common methods for treating marine aquaculture wastewater include mechanical filtration, biological treatment ponds, and chemical disinfection. However, in practical applications, these existing technologies have the following significant drawbacks: The equipment investment for these treatment methods is large, and their operating energy consumption is high. Furthermore, due to the high salinity of the seawater environment, mechanical and biological equipment is prone to corrosion and aging, leading to a significant reduction in equipment lifespan and high maintenance costs. Chemical disinfection methods easily leave chemical residues, disrupting the original ecological balance of the water body and failing to meet the requirements of green and environmentally friendly aquaculture. Simply relying on natural settling for purification has extremely low treatment efficiency and cannot meet the large-volume wastewater treatment needs of routine, large-scale aquaculture.

[0004] In summary, existing marine aquaculture wastewater treatment technologies often fail to simultaneously meet the multiple demands of low cost, zero pollution, high efficiency, and recycling. Therefore, developing a low-cost, eco-friendly marine aquaculture wastewater treatment technology that overcomes these shortcomings and balances ecological benefits is a pressing technical problem in the field of marine aquaculture pollution control. Summary of the Invention

[0005] The present invention aims to provide a marine aquaculture ecological wastewater treatment system and method to solve the technical problems of high energy consumption and easy corrosion of existing marine aquaculture wastewater treatment equipment, easy residue of chemical agents causing secondary pollution, and low efficiency of simple natural static purification and difficulty in recycling.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A marine aquaculture ecological wastewater treatment system includes a wastewater collection area, an ecological sedimentation area, an emergent plant purification area, a floating-leaved plant purification area, a benthic organism synergistic purification area, and a water quality conservation and return area connected in sequence. The wastewater collection area is used to collect wastewater from marine aquaculture and introduce it into the ecological sedimentation area. The ecological sedimentation zone is equipped with a slow-flow structure to reduce water flow velocity and promote the sedimentation of solid pollutants. The emergent plant purification zone is equipped with salt-tolerant emergent plants. The floating-leaf plant purification area is equipped with planting carriers and water-purifying floating-leaf plants cultivated on the planting carriers. The benthic organism synergistic purification zone is equipped with filter-feeding benthic organisms and halophilic microbial communities. The water conservation and return zone is equipped with a water circulation and reuse channel connected to the aquaculture pond, and the water conservation and return zone is also equipped with a reverse return channel to guide substandard water back to the ecological settlement zone.

[0007] Furthermore, the slow-flow structure includes multiple levels of slow-flow barriers arranged alternately within the ecological settlement zone, and the height of the multiple levels of slow-flow barriers gradually decreases along the direction of water flow.

[0008] Furthermore, the multi-stage flow-retardant retaining wall is constructed using stones and eco-friendly concrete.

[0009] Furthermore, the salt-tolerant emergent plants are selected from any one or more combinations of reeds, Suaeda salsa, and Acorus calamus; the planting spacing of the salt-tolerant emergent plants is 20cm-35cm.

[0010] Furthermore, a modified porous biochar carrier is mixed and laid in the bottom mud layer of the benthic organism synergistic purification zone. The modified porous biochar carrier is used to provide an expanded biofilm attachment microenvironment for the halophilic microbial community in the benthic organism synergistic purification zone.

[0011] Furthermore, the planting carrier is a perforated buoyancy board, which can float up and down with the water level in the floating leaf plant purification area.

[0012] Furthermore, the water-purifying floating-leaved plants are selected from salt-tolerant water lilies and Malayan pondweed; the filter-feeding benthic organisms include any one or more combinations of razor clams, clams, and sandworms; and the halophilic microbial community includes any one or more combinations of photosynthetic bacteria, nitrifying bacteria, and halophilic Bacillus.

[0013] Furthermore, the water quality conservation and reflux zone and the benthic organism co-purification zone are respectively equipped with multi-parameter water quality monitoring components including dissolved oxygen sensors, ammonia nitrogen sensors and salinity sensors; the benthic organism co-purification zone is also equipped with micro-nano aeration devices, and the top of the benthic organism co-purification zone is covered with a light-transmitting and heat-insulating canopy.

[0014] Furthermore, the marine aquaculture ecological wastewater treatment system also includes a central PLC control unit, which is electrically connected to the multi-parameter water quality monitoring component, the micro-nano aeration device, and the control valve located on the reverse flow channel. The central PLC control unit is configured to: automatically start the micro-nano aeration device when the multi-parameter water quality monitoring component detects that the dissolved oxygen in the benthic organism co-purification zone is lower than the set threshold; and automatically open the control valve when the multi-parameter water quality monitoring component detects that the water quality indicators in the water conservation and return zone do not meet the standards, so that the substandard water body can be purified in a closed loop through the reverse return channel.

[0015] A method for treating marine aquaculture wastewater includes the following steps: S1. The wastewater generated by aquaculture is uniformly introduced into the sewage collection area and smoothly transported to the ecological sedimentation area. The slow-flow structure in the ecological sedimentation area reduces the water flow velocity, so that large particles of impurities in the wastewater settle naturally under the action of gravity, thus completing solid-liquid separation. S2. After solid-liquid separation, the water flows into the emergent plant purification zone, where the roots of salt-tolerant emergent plants in the purification zone adsorb and decompose nitrogen and phosphorus pollutants in the water. S3. Water continuously flows into the floating-leaved plant purification zone. The floating-leaved plants in the purification zone provide shade to inhibit the growth of harmful algae and use underwater roots to trap fine suspended matter. S4. Water flows into the benthic organism co-purification zone, where filter-feeding benthic organisms filter organic debris and utilize beneficial halophilic microbial communities to deeply degrade ammonia nitrogen and nitrite in the water. S5. The water, after deep purification, flows into the water quality conservation and return area for settling to stabilize the water quality. The water quality is then tested. If the test is qualified, the water is diverted back to the aquaculture pond for recycling through the water circulation and reuse channel. If the test fails to meet the standards, the water is diverted back to the ecological settling area through the reverse return channel for secondary ecological purification.

[0016] Compared with the prior art, the beneficial effects of the present invention are: the multi-level gradient ecological purification structure constructed by the present invention relies on the synergistic chain of salt-tolerant plants, filter-feeding benthic organisms and highly active halophilic microorganisms to achieve wastewater self-purification throughout the process, and integrates microenvironment enhancement, multi-parameter intelligent monitoring and adaptive feedback mechanisms. First, the system's operation and daily purification primarily rely on the natural ecological chain's self-flow drive, requiring minimal addition of chemical agents. This not only achieves the ecological and environmental protection goal of zero chemical residues but also significantly reduces the overall energy consumption costs of construction and operation. Second, the system utilizes native salt-tolerant marine flora and fauna and domesticated halophilic microorganisms, possessing natural adaptability and immunity to the high-salt corrosive environment of seawater, overcoming the shortcomings of traditional mechanical equipment such as easy aging and corrosion and short lifespan. Simultaneously, the modified porous biochar carrier mixed and laid in the benthic organism co-purification zone greatly expands the biofilm attachment microenvironment, significantly improving the deep biochemical degradation rate of ammonia nitrogen and nitrite under high-salt conditions. Third, the system's staggered multi-level barriers achieve efficient initial solid-liquid separation. Combined with subsequent algae control, filter feeding, and deep detoxification stages, it can simultaneously and stably remove residual feed, feces, suspended solids, nutrients, and toxic substances such as ammonia nitrogen from the effluent. The effluent indicators are excellent, meeting both environmental and safety discharge requirements and enabling direct water recycling in aquaculture ponds. Finally, the system incorporates a climate-adaptive structure and flexible adaptive regulation and control. The light-transmitting and heat-insulating canopy ensures the system's metabolic activity and resilience in low-temperature winter environments. By linking multi-parameter water quality monitoring components with a central PLC control unit, intelligent low-consumption oxygen replenishment based on real-time dissolved oxygen levels at the bottom layer and closed-loop secondary circulation purification control based on final effluent indicators are achieved. This invention overcomes the technical pain points of traditional open-type ecological purification systems, such as susceptibility to collapse under extreme weather conditions and inability to dynamically respond to sudden water quality deterioration, and has extremely high value for promotion and practical application. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall system water flow structure layout of the present invention; Figure 2 A flowchart of the ecological zone purification process; Figure 3 This is a block diagram showing the connection of the intelligent control system module of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The present invention will be further described in detail below with reference to the embodiments.

[0020] like Figure 1-3 As shown, the marine aquaculture ecological wastewater treatment system of this invention includes sequentially connected wastewater collection area, ecological sedimentation area, emergent plant purification area, floating-leaved plant purification area, benthic organism synergistic purification area, and water quality conservation and return area. The entire system can be directly constructed using existing aquaculture ditches, idle ponds, and other natural terrain modifications, without the need for large-scale electric filtration or chemical dosing equipment. To enhance the system's environmental resilience and treatment efficiency, this system introduces an ecological enhancement structure and a micro-intervention adaptive control system on the basis of purely natural ecological purification.

[0021] The wastewater collection area (such as a wastewater collection tank) is used to collect the initial wastewater discharged from seawater ponds or tidal flat aquaculture and smoothly introduce it into the ecological sedimentation area.

[0022] The ecological settling zone is equipped with a slow-flow structure to reduce water flow velocity and promote the natural gravity settling of solid pollutants. In this embodiment, the slow-flow structure includes multi-level slow-flow barriers arranged in an alternating pattern within the ecological settling zone. These multi-level barriers are constructed using stones and ecological concrete (a special type of concrete with high permeability, a rough surface, and conducive to biofilm formation), and the surface of the barriers allows for the attachment of natural microalgae or microorganisms. To create a reasonable flow velocity gradient, the height of each barrier gradually decreases along the direction of water flow (e.g., the first barrier is 0.8m above the bottom of the pool, the second is 0.6m, and the third is 0.4m), resulting in a slightly stepped, diffused flow. This effectively removes large particulate solid pollutants such as uneaten food, feces, and silt from the effluent, and naturally forms a silt sedimentation layer at the bottom between the barriers.

[0023] The emergent plant purification zone is connected to the outlet of the ecological sedimentation zone. This zone is planted with salt-tolerant emergent plants, specifically any one or more combinations of reeds, Suaeda salsa, and Acorus calamus, which possess strong salt and alkali tolerance and high nitrogen and phosphorus absorption efficiency. In this embodiment, the planting spacing of the salt-tolerant emergent plants is controlled at 20cm-35cm (e.g., 25cm or 30cm). This density ensures that the plant roots are interwoven in the water, forming a dense bio-adsorption network, while preventing poor plant growth or complete blockage of water flow due to excessive density. The interwoven plant roots penetrate deep into the middle and lower layers of the water, extensively adsorbing, enriching, and degrading nutrients such as ammonia nitrogen and total phosphorus in the water. Simultaneously, the natural microbial community attached to the root surface decomposes organic matter.

[0024] The floating-leaved plant purification zone sequentially receives water flow from the emergent plant purification zone. This zone contains planting carriers and water-purifying floating-leaved plants cultivated on these carriers. The planting carriers are perforated buoyancy boards (e.g., mesh-shaped boards made of environmentally friendly high-density polyethylene, HDPE). These perforated buoyancy boards are positioned within the pool via guide rails or positioning ropes at both ends, allowing them to adaptively float up and down with changes in water level within the floating-leaved plant purification zone, perfectly adapting to different water depths during different cultivation periods or tidal changes. The water-purifying floating-leaved plants are one or two species selected from salt-tolerant water lilies and Potamogeton malaianus. The large leaves of these floating-leaved plants float on the water surface, effectively blocking sunlight and cutting off the energy source for photosynthesis of harmful algae (such as cyanobacteria and dinoflagellates), inhibiting their rampant growth and red tide outbreaks. Simultaneously, their well-developed, underwater-hanging root systems have a secondary function of capturing fine suspended particles, significantly reducing water turbidity and improving water transparency.

[0025] The benthic organism synergistic purification zone is located downstream of the floating-leaved plant purification zone. This zone is stocked with filter-feeding benthic organisms and halophilic microorganisms. The filter-feeding benthic organisms include any one or more combinations of razor clams, clams, and sandworms (preferably mixed to construct a multi-dimensional ecological filter-feeding chain in the vertical space above and below the mud surface). These benthic organisms, through their daily physiological filter-feeding behavior, ingest and digest large quantities of residual micro-organic debris and micro-suspended impurities in the water. Simultaneously, a highly active halophilic microorganism community, specifically including photosynthetic bacteria, nitrifying bacteria, and halophilic Bacillus, is introduced and cultivated within the zone. This halophilic microorganism community maintains high metabolic activity in the high-salt seawater environment and works synergistically with the benthic organisms to specifically and deeply degrade residual ammonia nitrogen, nitrite, and other substances highly toxic to farmed animals, achieving deep detoxification and purification of the water. To overcome the shortcomings of traditional pure mud bottom microorganisms, such as small attachment area and easy loss, a modified porous biochar carrier is mixed and laid in the bottom mud layer of the benthic organism co-purification zone. The large specific surface area and rich microporous structure of the modified porous biochar carrier can provide an expanded microenvironment for biofilm attachment of the halophilic microbial community, accelerating biofilm formation and colonization. In addition, to ensure the metabolic activity of microorganisms and benthic organisms under low winter temperatures, the top of the benthic organism co-purification zone is covered with a light-transmitting and heat-insulating canopy, utilizing the greenhouse effect for passive heat preservation.

[0026] The water conservation and recirculation zone is located at the end of the entire purification system. This zone is equipped with a water circulation and reuse channel connected to the aquaculture ponds (ponds or tidal flats) to guide purified water back to the aquaculture ponds for reuse. Simultaneously, the water conservation and recirculation zone also includes a reverse recirculation channel that guides substandard water back to the ecological settling zone at the front end (this channel can be equipped with a recirculation pump or low-energy valve control), thus constructing a closed-loop emergency purification mechanism to ensure the absolute safety of discharged or reused water quality.

[0027] To achieve closed-loop water quality monitoring and flexible micro-intervention, the system also includes a central PLC control unit. Multi-parameter water quality monitoring components, including dissolved oxygen, ammonia nitrogen, and salinity sensors, are respectively installed in the water conservation and reflux zone and the benthic organism co-purification zone; a micro-nano aeration device is also installed in the benthic organism co-purification zone. The central PLC control unit is electrically connected to the multi-parameter water quality monitoring components, the micro-nano aeration device, and the control valve located on the reverse reflux channel.

[0028] The central PLC control unit is equipped with adaptive adjustment logic: on the one hand, when the multi-parameter water quality monitoring component in the benthic organism co-purification zone detects that the dissolved oxygen in the water is lower than the set threshold (e.g., lower than the safe DO value required for benthic organism filter feeding and nitrification), the micro-nano aeration device is automatically started to provide localized and efficient oxygen supplementation. After the dissolved oxygen reaches the standard, the device is automatically shut down to save energy. On the other hand, when the multi-parameter water quality monitoring component in the water conservation and return flow zone detects that the water quality indicators of the final effluent do not meet the standards, the central PLC control unit automatically opens the control valve on the reverse return flow channel to pump the substandard water back to the front-end ecological sedimentation zone for closed-loop secondary ecological purification, thus completely eliminating the safety hazards caused by illegal discharge or reuse of tailwater.

[0029] Based on the same inventive concept described above, this invention also provides a method for treating marine aquaculture wastewater based on the above system, comprising the following steps: S1, Solid-Liquid Separation Stage: Wastewater from shrimp, fish, or shellfish pond aquaculture is collected in a unified wastewater collection area (collection trough) and then smoothly transported to the ecological sedimentation zone by gravity. Once in the ecological sedimentation zone, the water flow velocity is significantly reduced due to the obstruction and guidance of multiple flow-slowing barriers. Large particles of impurities such as uneaten feed, feces, and silt carried in the wastewater naturally settle under gravity, accumulating in the sludge sediment layer at the bottom of the pond, completing the initial solid-liquid separation. Staff can periodically (e.g., quarterly or after the aquaculture cycle) clean the bottom sludge to prevent secondary pollution caused by the accumulation of impurities.

[0030] S2, Emergent Plant Primary Purification Stage: After solid-liquid separation, the supernatant slowly and evenly flows from the end of the ecological sedimentation zone into the emergent plant purification zone. Through the extensive root systems of salt-tolerant emergent plants such as reeds, Suaeda salsa, and Acorus calamus planted at 20-35cm intervals in this zone, nitrogen and phosphorus nutrients in the water are adsorbed and intercepted over a large area. These nutrients are then initially decomposed by natural microorganisms attached to the roots, significantly reducing the overall pollution load on the water body.

[0031] S3, Secondary algae control and purification stage using floating-leaved plants: Water continuously flows out of the emergent plant purification zone and into the floating-leaved plant purification zone. Salt-tolerant water lilies, pondweed, and other floating-leaved plants, planted on perforated buoyancy boards, provide extensive surface shading, reducing light intensity in the lower water layers and effectively inhibiting the rampant proliferation of harmful algae. Simultaneously, the underwater roots of these floating-leaved plants continue to capture and intercept fine suspended pollutants in the water, further optimizing water transparency and basic physicochemical properties.

[0032] S4, Benthic-Microbial Synergistic Deep Detoxification Stage: Subsequently, the water flows into the benthic organism co-purification zone. At this point, the water pollution load has been significantly reduced. The introduced benthic organisms, such as razor clams, clams, and sandworms, continuously filter out the remaining microscopic organic debris and small impurities in the water. Simultaneously, the halophilic microbial flora, including photosynthetic bacteria, nitrifying bacteria, and halophilic Bacillus, which are artificially domesticated and cultivated in the water and at the bottom of the pond, stably reproduce and efficiently metabolize, completely converting highly toxic ammonia nitrogen and nitrite into non-toxic nitrates and other harmless substances, thus deeply eliminating the toxicity of the effluent to farmed animals.

[0033] At this stage, a modified porous biochar carrier, pre-mixed and laid at the bottom, provides an expanded microenvironment for the biofilm attachment of halophilic microorganisms; and a light-transmitting and heat-insulating canopy is used to insulate the water body.

[0034] S5, Cultivation, Regulation, and Recycling Stage: After deep purification, the water is finally discharged into the water conservation and return zone for settling. During this period, key ecological indicators such as salinity, dissolved oxygen (DO), and pH are stabilized and regulated to restore the water to the optimal state for the growth of farmed animals. At the outlet, the settled water is tested online or periodically. If the test indicators meet the standards for seawater aquaculture water or environmental discharge standards, the water recycling channel is opened, and the compliant water is safely diverted back to the aquaculture pond for reuse, or directly discharged into the nearshore environment. If, due to special reasons (such as heavy rain or overfeeding), a certain water quality indicator fails to meet the reuse requirements, the water recycling channel is closed, and the reverse return channel is opened. A return pump is used to divert the water back to the initial ecological settling zone, where it undergoes the entire multi-stage ecological purification process again until the water quality fully meets the standards.

[0035] During the operation of steps S4 and S5 above, the dissolved oxygen, ammonia nitrogen and salinity of the water body are monitored in real time using a multi-parameter water quality monitoring component, and the monitoring data is fed back to the central PLC control unit. The central PLC control unit performs adaptive adjustments in real time based on the received monitoring data: if the dissolved oxygen in the benthic organism co-purification zone is lower than the set threshold, the micro-nano aeration device is automatically activated to supplement oxygen; the final water body after settling is tested and evaluated for water quality. If the test is qualified, the water body is guided back to the aquaculture pond for recycling through the water circulation reuse channel; if the test fails to meet the standard, the control valve is automatically opened to guide the water body back to the ecological sedimentation zone through the reverse return channel for secondary closed-loop purification.

[0036] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A marine aquaculture ecological wastewater treatment system, characterized in that: It includes a sequentially connected sewage collection area, ecological sedimentation area, emergent plant purification area, floating leaf plant purification area, benthic organism synergistic purification area, and water quality conservation and return area; The wastewater collection area is used to collect wastewater from marine aquaculture and introduce it into the ecological sedimentation area. The ecological sedimentation zone is equipped with a flow-slowing structure to reduce water flow velocity and promote the sedimentation of solid pollutants. The emergent plant purification zone is equipped with salt-tolerant emergent plants. The floating-leaf plant purification area is equipped with planting carriers and water-purifying floating-leaf plants cultivated on the planting carriers. The benthic organism synergistic purification zone is equipped with filter-feeding benthic organisms and halophilic microbial communities. The water conservation and return zone is equipped with a water circulation and reuse channel connected to the aquaculture pond, and the water conservation and return zone is also equipped with a reverse return channel to guide substandard water back to the ecological settlement zone.

2. The marine aquaculture ecological wastewater treatment system according to claim 1, characterized in that: The slow-flow structure includes multiple levels of slow-flow barriers arranged in a staggered manner within the ecological settlement zone, and the height of the multiple levels of slow-flow barriers gradually decreases along the direction of water flow.

3. The marine aquaculture ecological wastewater treatment system according to claim 2, characterized in that: The multi-stage flow-retardant retaining wall is constructed using stones and eco-friendly concrete.

4. The marine aquaculture ecological wastewater treatment system according to claim 1, characterized in that: The salt-tolerant emergent plants are selected from any one or more combinations of reeds, Suaeda salsa, and Acorus calamus; the planting spacing of the salt-tolerant emergent plants is 20cm-35cm.

5. The marine aquaculture ecological wastewater treatment system according to claim 1, characterized in that: Modified porous biochar carriers are mixed and laid in the bottom mud layer of the benthic organism synergistic purification zone. The modified porous biochar carriers are used to provide an expanded biofilm attachment microenvironment for the halophilic microbial community in the benthic organism synergistic purification zone.

6. The marine aquaculture ecological wastewater treatment system according to claim 1, characterized in that: The planting carrier is a perforated buoyancy board, which can float up and down with the water level in the floating leaf plant purification area.

7. The marine aquaculture ecological wastewater treatment system according to claim 1, characterized in that: The water-purifying floating-leaved plants are selected from salt-tolerant water lilies and Malayan pondweed; the filter-feeding benthic organisms include any one or more combinations of razor clams, clams, and sandworms; the halophilic microbial community includes any one or more combinations of photosynthetic bacteria, nitrifying bacteria, and halophilic Bacillus.

8. The marine aquaculture ecological wastewater treatment system according to claim 1, characterized in that: The water quality conservation and reflux zone and the benthic organism co-purification zone are respectively equipped with multi-parameter water quality monitoring components including dissolved oxygen sensors, ammonia nitrogen sensors and salinity sensors; the benthic organism co-purification zone is also equipped with micro-nano aeration devices, and the top of the benthic organism co-purification zone is covered with a light-transmitting and heat-insulating canopy.

9. A marine aquaculture ecological wastewater treatment system according to claim 1, characterized in that: It also includes a central PLC control unit, which is electrically connected to the multi-parameter water quality monitoring component, the micro-nano aeration device, and the control valve located on the reverse flow channel. The central PLC control unit is configured to: automatically start the micro-nano aeration device when the multi-parameter water quality monitoring component detects that the dissolved oxygen in the benthic organism co-purification zone is lower than the set threshold; and automatically open the control valve when the multi-parameter water quality monitoring component detects that the water quality indicators in the water conservation and return zone do not meet the standards, so that the substandard water body can be purified in a closed loop through the reverse return channel.

10. A method for treating marine aquaculture wastewater, characterized in that, Includes the following steps: S1. The wastewater generated by aquaculture is uniformly introduced into the sewage collection area and smoothly transported to the ecological sedimentation area. The slow-flow structure in the ecological sedimentation area reduces the water flow velocity, so that large particles of impurities in the wastewater settle naturally under the action of gravity, thus completing solid-liquid separation. S2. After solid-liquid separation, the water flows into the emergent plant purification zone, where the roots of salt-tolerant emergent plants in the purification zone adsorb and decompose nitrogen and phosphorus pollutants in the water. S3. Water continuously flows into the floating-leaved plant purification zone. The floating-leaved plants in the purification zone provide shade to inhibit the growth of harmful algae and use underwater roots to trap fine suspended matter. S4. Water flows into the benthic organism co-purification zone, where filter-feeding benthic organisms filter organic debris and utilize beneficial halophilic microbial communities to deeply degrade ammonia nitrogen and nitrite in the water. S5. The water, after deep purification, flows into the water quality conservation and return area for settling to stabilize the water quality. The water quality is then tested. If the test is qualified, the water is diverted back to the aquaculture pond for recycling through the water circulation and reuse channel. If the test fails to meet the standards, the water is diverted back to the ecological settling area through the reverse return channel for secondary ecological purification.

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