Energy-saving and carbon-reducing ex-situ treatment system and method for recirculating aquaculture wastewater

Abstract

This invention relates to the field of aquaculture wastewater treatment technology, and discloses an energy-saving, carbon-reducing, off-site treatment system and method for recirculating aquaculture wastewater. The system includes four interconnected treatment zones, from left to right: a wetland purification zone, a three-dimensional ecological purification zone, a membrane biological treatment zone, and an ecological conservation purification zone. The system utilizes the wetland purification zone to create a filtration and anaerobic environment, designs the three-dimensional ecological purification zone as a facultative anaerobic environment, improves the aerobic biochemical treatment effect through the membrane ecological purification zone, and finally, through deep purification and regulation in the ecological conservation zone, the effluent is returned to the aquaculture pond for reuse. Through the overall operation of the system, the pollution load during the aquaculture process is continuously reduced, solving the technical problem of ensuring water quality and treating polluted water to sustainably meet the needs of aquaculture while maintaining uninterrupted water circulation.

Description

Technical Field

[0001] This invention relates to the field of aquaculture wastewater treatment technology, and in particular to an energy-saving, carbon-reducing, off-site treatment system and method for recirculating aquaculture wastewater. Background Technology

[0002] Currently, much of the wastewater from aquaculture is discharged without treatment. After a season of aquaculture, the wastewater is directly discharged, and then clean water is introduced into the next aquaculture cycle after the ponds are dried and the bottom mud is solidified. This method of aquaculture not only results in untreated polluted water, but also affects the taste and quality of fish and aquatic products raised in polluted water, and in severe cases, may cause fish diseases or even death.

[0003] In existing technologies, a small number of concentrated aquaculture areas may use aeration to increase the oxygen content in the water, or reduce the deterioration of stagnant water quality by circulating a small amount of water. However, these measures cannot effectively reduce the pollution load of aquaculture wastewater, and therefore have little significance in reducing environmental pollution, improving water quality, and enhancing the quality of aquatic products. Summary of the Invention (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides an energy-saving and carbon-reducing off-site treatment system and method for recirculating aquaculture wastewater. Through the overall operation of the system, the pollution load during the aquaculture process is continuously reduced, solving the technical problem of ensuring water quality and treating polluted water in aquaculture without interrupting the circulation of water, thus sustainably meeting the needs of aquaculture. (II) Technical Solution

[0005] To achieve the above objectives, the present invention provides the following technical solution: An energy-saving and carbon-reducing off-site treatment system for recirculating aquaculture wastewater includes four interconnected treatment zones, which, from left to right, are a wetland purification zone, a three-dimensional ecological purification zone, a membrane biological treatment zone, and an ecological conservation purification zone. The wetland purification area includes an inlet baffle and an outlet baffle. The area between the inlet baffle and the outlet baffle is filled with biological filter media. Several emergent plants of the first area are set on the biological filter media. A lower inlet hole is opened below the inlet baffle, and an upper outlet hole is opened above the outlet baffle. The three-dimensional ecological purification zone includes floating pipes on the water surface. A floating plant support net is set up in the rectangular area formed by the floating pipes. Several second-area floating plants are set up in the floating plant support net. Microbial biofilms are symmetrically set on the left and right sides of the rectangular area formed by the floating pipes. The membrane biotreatment zone includes a MABR membrane aerated biofilm reactor, and a third submerged plant area is set below the MABR membrane aerated biofilm reactor. The ecological conservation and purification zone includes emergent plants in the fourth area on the periphery, and submerged plants in the middle area of ​​the fourth area emergent plants.

[0006] Furthermore, the wetland purification zone utilizes the adsorption of the biological filter media, the attachment, reproduction, and decomposition of microorganisms in the water, the absorption and decomposition by the roots of emergent plants in the first area, and the anaerobic digestion and degradation of pollutants; the biological filter media is a porous biological filter media.

[0007] Furthermore, the three-dimensional ecological purification zone decomposes pollutants through the root system of floating plants in the second area and through the attachment and reproduction of microorganisms.

[0008] Furthermore, the membrane biological treatment zone is provided with an aerobic environment through nano-aeration via the MABR membrane aeration biofilm reactor, and the decomposition of pollutants is further enhanced by microorganisms and submerged plants in the third zone.

[0009] Furthermore, the ecological conservation and purification zone further purifies the water quality through emergent plants and submerged plants in the fourth area, thereby improving water transparency and eco-friendliness.

[0010] The entire treatment process, consisting of four steps from S1 to S4, requires no chemical additives. The system's energy consumption is concentrated in the nano-aeration stage, with an electricity consumption of ≤0.15 kWh per ton of water.

[0011] To achieve the above objectives, the present invention also provides the following technical solution: A method for energy-saving and carbon-reducing off-site treatment of recirculating aquaculture wastewater, using the aforementioned energy-saving and carbon-reducing off-site treatment system for recirculating aquaculture wastewater, includes the following steps: S1. Wetland Anaerobic Purification Treatment: Wastewater containing pollutants is evenly introduced into the wetland purification area through the lower inlet hole, so that the wastewater passes through the biological filter media for physical adsorption, decomposition by anaerobic microorganisms in the water, and absorption by the roots of emergent plants in the first area to remove suspended solids, nitrate nitrogen and chemical oxygen demand. S2. Three-dimensional ecological facultative oxygen treatment: The effluent from the wetland purification area is introduced into the three-dimensional ecological purification area through the upper effluent outlet. After the pollutants are absorbed by the roots of floating plants in the second area and degraded by microbial biofilm, the water is covered by the growth of surface plants to form a facultative oxygen environment, which further reduces nitrogen, phosphorus and organic pollutants. S3. Membrane biological aerobic treatment: oxygen is supplied to the water body through the nano-aeration device of the MABR membrane aeration biofilm reactor, combined with the purification effect of submerged plants in the third zone, to enhance the decomposition of ammonia nitrogen and chemical oxygen demand in an aerobic environment. S4. Ecological Conservation and Purification Treatment: The treated water is then introduced into the ecological conservation and purification zone. Through the ecological synergy between emergent plants and submerged plants in the fourth zone, the water transparency and eco-friendliness are improved, and the water is ultimately reused in the aquaculture system.

[0012] Furthermore, in step S1, the emergent plants in the first area are canna lilies, cattails, or calamus, and the layer height of the biological filter media (103) is 0.8-1.2 meters.

[0013] Furthermore, in step S2, the floating plants in the second area are water hyacinth, foxtail grass, or pennywort, and the microbial biofilm is made of polyethylene or polypropylene mesh material.

[0014] Furthermore, in step S3, the aeration rate of the nano-aeration device is 0.5-1.0 L / min·m², the aeration oxygen supply efficiency is 3 to 4 times that of general aeration equipment, and the biofilm thickness on the MABR membrane surface is 0.5-2.0 mm.

[0015] Furthermore, in step S4, the planting density of emergent plants in the fourth area is 8-12 plants / m², and the coverage rate of submerged plants in the fourth area is 30%-50%. (III) Beneficial Effects

[0016] Compared with existing technologies, this invention provides an energy-saving and carbon-reducing off-site treatment system and method for recirculating aquaculture wastewater, which has the following beneficial effects: 1. This system employs a four-stage sequential treatment process: wetland purification zone → three-dimensional ecological zone → membrane biological treatment zone → ecological conservation zone, forming a closed-loop water cycle. Test data shows that after the entire process, the ammonia nitrogen removal rate reaches 92%, the total phosphorus removal rate reaches 87%, and dissolved oxygen is maintained above 5 mg / L. The unique MABR membrane aeration technology increases the water recycling rate to 85%, saving 30% of water compared to traditional systems.

[0017] 2. This system employs a gravity flow design (reducing energy consumption by 40%) combined with nano-aeration technology (energy consumption is only 1 / 5 of traditional aeration). The photovoltaic-driven water pump consumes no more than 1500 kWh of electricity annually, reducing CO2 emissions by 2.3 tons per year. Microbial biofilm technology replaces 60% of mechanical filtration equipment, further reducing energy consumption.

[0018] 3. The system utilizes biological filter media (with a service life of over 5 years) and a self-balancing ecological community to form a stable purification system, requiring only quarterly inspections of the floating tube array and membrane modules. IoT sensors monitor water quality parameters in real time, with a failure rate of less than 0.5 times per year, reducing maintenance hours by 80% compared to traditional systems.

[0019] 4. The system utilizes an ecological conservation area planted with water chestnuts (yield 800 kg per mu) and water celery (4 harvests per year). Based on current market prices, each 1000 m² treatment system can generate an annual revenue of 12,000-18,000 yuan. Simultaneously, the resulting aquatic plant community provides spawning grounds for 12 native fish species, increasing the biodiversity index by 2.3 times. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an energy-saving and carbon-reducing off-site treatment system for recirculating aquaculture wastewater according to the present invention. Figure 2 This is a schematic diagram of the wetland purification zone in an energy-saving and carbon-reducing off-site treatment system for recirculating aquaculture wastewater according to the present invention. Figure 3 These are front and top views of a three-dimensional ecological purification zone in an off-site energy-saving and carbon-reducing treatment system for recirculating aquaculture wastewater according to the present invention. Figure 4 This is a schematic diagram of the membrane biological treatment zone in an energy-saving and carbon-reducing off-site treatment system for recirculating aquaculture wastewater according to the present invention. Figure 5 This is a schematic diagram of the ecological conservation and purification zone in an energy-saving and carbon-reducing off-site treatment system for recirculating aquaculture wastewater according to the present invention. In the diagram: 1. Wetland purification zone; 101. Inlet baffle; 102. Outlet baffle; 103. Biological filter media; 104. Emergent plants in the first zone; 105. Lower inlet hole; 106. Upper outlet hole; 2. Three-dimensional ecological purification zone; 201. Floating pipe; 202. Floating plant support net; 203. Floating plants in the second zone; 204. Microbial biofilm; 3. Membrane biological treatment zone; 301. MABR membrane aeration biofilm reactor; 302. Submerged plants in the third zone; 4. Ecological conservation purification zone; 401. Emergent plants in the fourth zone; 402. Submerged plants in the fourth zone. Detailed Implementation

[0021] 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. Example

[0022] Please see Figure 1-5 This embodiment provides an energy-saving and carbon-reducing off-site treatment system for recirculating aquaculture wastewater. The system includes four interconnected treatment zones, which are, from left to right, a wetland purification zone 1, a three-dimensional ecological purification zone 2, a membrane biological treatment zone 3, and an ecological conservation purification zone 4. The wetland purification zone 1 includes an inlet baffle 101 and an outlet baffle 102. The area between the inlet baffle 101 and the outlet baffle 102 is filled with biological filter media 103. Several emergent plants 104 of the first zone are arranged on the biological filter media 103. A lower inlet hole 105 is opened below the inlet baffle 101, and an upper outlet hole 106 is opened above the outlet baffle 102. The wetland purification zone 1 degrades pollutants through adsorption by the biological filter media 103, decomposition by the attachment and reproduction of microorganisms in the water, absorption and decomposition by the roots of the emergent plants 104 of the first zone, and anaerobic digestion. The biological filter media 103 is a porous biological filter media. The three-dimensional ecological purification zone 2 includes floating pipes 201 on the water surface. A floating plant support net 202 is set within the rectangular area formed by the floating pipes 201. Several second-area floating plants 203 are set within the floating plant support net 202. Microbial biofilms 204 are symmetrically set on the left and right sides of the rectangular area formed by the floating pipes 201. The three-dimensional ecological purification zone 2 decomposes pollutants through the root system of the second-area floating plants 203 and the attachment and reproduction of microbial biofilms. The membrane biological treatment zone 3 includes a MABR membrane aeration biofilm reactor 301, and a third submerged plant 302 is set below the MABR membrane aeration biofilm reactor 301. The membrane biological treatment zone 3 provides an aerobic environment through nano-aeration by the MABR membrane aeration biofilm reactor 301, and further enhances the decomposition of pollutants through microorganisms and the third submerged plant 302. The ecological conservation and purification zone 4 includes emergent plants 401 in the fourth area set on the periphery, and submerged plants 402 in the fourth area set in the middle area of ​​emergent plants 401. The ecological conservation and purification zone 4 further purifies the water quality and improves the water transparency and eco-friendliness through emergent plants 401 and submerged plants 402 in the fourth area. Example

[0023] This embodiment provides an energy-saving and carbon-reducing off-site treatment method for recirculating aquaculture wastewater, which is used in the energy-saving and carbon-reducing off-site treatment system for recirculating aquaculture wastewater of Embodiment 1. The working principle of this energy-saving and carbon-reducing off-site treatment system for recirculating aquaculture wastewater includes the following steps: S1. Wetland Anaerobic Purification Treatment: Wastewater containing pollutants is evenly introduced into the wetland purification zone 1 through the lower inlet hole 105, so that the wastewater passes through the biological filter media 103 for physical adsorption, decomposition by anaerobic microorganisms in the water and absorption by the roots of emergent plants 104 in the first area, to remove suspended solids, nitrate nitrogen and chemical oxygen demand. S2. Three-dimensional ecological facultative oxygen treatment: The effluent from the wetland purification zone is introduced into the three-dimensional ecological purification zone 2 through the upper effluent hole 106. After the root system of the floating plants 203 in the second zone absorbs pollutants and the microbial biofilm 204 degrades pollutants, the surface plants grow and cover to form a facultative oxygen environment, further reducing nitrogen, phosphorus and organic pollutants. S3. Membrane biological aerobic treatment: oxygen is supplied to the water body through the nano-aeration device of the MABR membrane aeration biofilm reactor 301, combined with the purification effect of the submerged plants 302 in the third zone, to enhance the decomposition of ammonia nitrogen and chemical oxygen demand in an aerobic environment. S4. Ecological conservation and purification treatment: The treated water is then introduced into the ecological conservation and purification zone 4. Through the ecological synergy of emergent plants 401 and submerged plants 402 in the fourth zone, the water transparency and eco-friendliness are improved, and the water is ultimately reused in the aquaculture system.

[0024] In the above-described embodiments, in step S1, the emergent plants 104 in the first zone are canna lilies, cattails, or sweet flag, and the layer height of the biological filter media 103 is 0.8-1.2 meters. In step S2, the floating plants 203 in the second zone are water hyacinth, foxtail grass, or pennywort, and the microbial biofilm 204 is made of polyethylene or polypropylene mesh material. In step S3, the aeration rate of the nano-aeration device is 0.5-1.0 L / min·m², and the aeration oxygen supply efficiency is 3-4 times that of general aeration equipment. The biofilm thickness on the MABR membrane surface is 0.5-2.0 mm. In step S4, the planting density of emergent plants 401 in the fourth zone is 8-12 plants / m², and the coverage rate of submerged plants 402 in the fourth zone is 30%-50%. The entire treatment process of steps S1-S4 does not require the addition of chemical agents, and the system energy consumption is concentrated in the nano-aeration stage, with a power consumption of ≤0.15 kWh per ton of water.

[0025] In summary, this system utilizes wetland purification zones to create filtration and anaerobic environments, designs three-dimensional ecological purification zones as facultative anaerobic environments, enhances aerobic biochemical treatment through membrane ecological purification zones, and finally achieves deep purification and regulation through ecological conservation zones, allowing the effluent to be returned to the aquaculture ponds for reuse. Its specific advantages are reflected in the following four points: 1. This system employs a four-stage sequential treatment process: wetland purification zone → three-dimensional ecological zone → membrane biological treatment zone → ecological conservation zone, forming a closed-loop water cycle. Test data shows that after the entire process, the ammonia nitrogen removal rate reaches 92%, the total phosphorus removal rate reaches 87%, and dissolved oxygen is maintained above 5 mg / L. The unique MABR membrane aeration technology increases the water recycling rate to 85%, saving 30% of water compared to traditional systems.

[0026] 2. This system employs a gravity flow design (reducing energy consumption by 40%) combined with nano-aeration technology (energy consumption is only 1 / 5 of traditional aeration). The photovoltaic-driven water pump consumes no more than 1500 kWh of electricity annually, reducing CO2 emissions by 2.3 tons per year. Microbial biofilm technology replaces 60% of mechanical filtration equipment, further reducing energy consumption.

[0027] 3. The system utilizes biological filter media (with a service life of over 5 years) and a self-balancing ecological community to form a stable purification system, requiring only quarterly inspections of the floating tube array and membrane modules. IoT sensors monitor water quality parameters in real time, with a failure rate of less than 0.5 times per year, reducing maintenance hours by 80% compared to traditional systems.

[0028] 4. The system utilizes an ecological conservation area planted with water chestnuts (yield 800 kg per mu) and water celery (4 harvests per year). Based on current market prices, each 1000 m² treatment system can generate an annual revenue of 12,000-18,000 yuan. Simultaneously, the resulting aquatic plant community provides spawning grounds for 12 native fish species, increasing the biodiversity index by 2.3 times.

[0029] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover a 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 a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0030] 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. An energy-saving and carbon-reducing off-site treatment system for recirculating aquaculture wastewater, characterized in that: The system includes four interconnected treatment zones, which are, from left to right, a wetland purification zone (1), a three-dimensional ecological purification zone (2), a membrane biological treatment zone (3), and an ecological conservation purification zone (4). The wetland purification zone (1) includes an inlet baffle (101) and an outlet baffle (102). The area between the inlet baffle (101) and the outlet baffle (102) is filled with biological filter media (103). Several emergent plants (104) of the first area are arranged on the biological filter media (103). A lower inlet hole (105) is opened below the inlet baffle (101), and an upper outlet hole (106) is opened above the outlet baffle (102). The three-dimensional ecological purification zone (2) includes floating pipes (201) floating on the water surface. A floating plant support net (202) is set in the rectangular area formed by the floating pipes (201). Several second-area floating plants (203) are set in the floating plant support net (202). Microbial biofilms (204) are symmetrically set on the left and right sides of the rectangular area formed by the floating pipes (201). The membrane biological treatment zone (3) includes a MABR membrane aerated biofilm reactor (301), and a third submerged plant (302) is set below the MABR membrane aerated biofilm reactor (301). The ecological conservation and purification zone (4) includes emergent plants (401) in the fourth area set on the periphery, and submerged plants (402) in the fourth area set in the middle area of ​​the emergent plants (401).

2. The energy-saving and carbon-reducing ex-situ treatment system for recirculating aquaculture wastewater according to claim 1, characterized in that: The wetland purification zone (1) degrades pollutants through adsorption by the biological filter media (103), decomposition by microorganisms attached to and reproduced in the water, absorption and decomposition by the roots of emergent plants (104) in the first area, and anaerobic digestion; the biological filter media (103) is a porous biological filter media.

3. The energy-saving and carbon-reducing ex-situ treatment system for recirculating aquaculture wastewater according to claim 1, characterized in that: The three-dimensional ecological purification zone (2) absorbs pollutants through the root system of floating plants (203) in the second area, and decomposes pollutants through the attachment and reproduction of microorganisms, and forms a facultative anaerobic environment through the growth and coverage of surface plants.

4. The energy-saving and carbon-reducing ex-situ treatment system for recirculating aquaculture wastewater according to claim 1, characterized in that: The membrane biological treatment zone (3) is aerated by the MABR membrane aeration biofilm reactor (301) to provide an aerobic environment, and the decomposition of pollutants is further enhanced by microorganisms and the submerged plants (302) in the third zone.

5. The energy-saving and carbon-reducing ex-situ treatment system for recirculating aquaculture wastewater according to claim 1, characterized in that: The ecological conservation and purification zone (4) further purifies the water quality through the emergent plants (401) and submerged plants (402) in the fourth area.

6. A method for energy-saving, carbon-reducing, and off-site treatment of recirculating aquaculture wastewater, used in the recirculating aquaculture wastewater energy-saving, carbon-reducing, and off-site treatment system according to any one of claims 1-5, characterized in that: Includes the following steps: S1. Wetland Anaerobic Purification Treatment: Wastewater containing pollutants is evenly introduced into the wetland purification area (1) through the lower inlet hole (105), so that the wastewater passes through the biological filter media (103) for physical adsorption, decomposition by anaerobic microorganisms in the water and absorption by the roots of emergent plants (104) in the first area, thereby removing suspended solids, nitrate nitrogen and chemical oxygen demand. S2. Three-dimensional ecological facultative oxygen treatment: The effluent from the wetland purification area is introduced into the three-dimensional ecological purification area (2) through the upper effluent hole (106). After the root system of the floating plants (203) in the second area absorbs pollutants and the microbial biofilm (204) degrades pollutants, the surface plants grow and cover to form a facultative oxygen environment, further reducing nitrogen, phosphorus and organic pollutants. S3. Membrane biological aerobic treatment: oxygen is supplied to the water body through the nano-aeration device of the MABR membrane aerated biofilm reactor (301), combined with the purification effect of the submerged plants (302) in the third zone, to enhance the decomposition of ammonia nitrogen and chemical oxygen demand in an aerobic environment. S4. Ecological conservation and purification treatment: The treated water is further introduced into the ecological conservation and purification zone (4), and the water quality is further purified through the ecological synergy of emergent plants (401) and submerged plants (402) in the fourth zone, and finally reused in the aquaculture system.

7. The energy-saving and carbon-reducing ex-situ treatment method of recirculating aquaculture wastewater according to claim 6, characterized in that: In step S1, the emergent plants (104) in the first area are canna, cattail or sweet flag, and the height of the filler layer of the biological filter media (103) is 0.8-1.2 meters.

8. The energy-saving and carbon-reducing ex-situ treatment method of recirculating aquaculture wastewater according to claim 6, characterized in that: In step S2, the floating plants (203) in the second area are water hyacinth, foxtail grass, or pennywort, and the microbial biofilm (204) is made of polyethylene or polypropylene mesh material.

9. The method for energy-saving, carbon-reducing, and off-site treatment of recirculating aquaculture wastewater according to claim 6, characterized in that: In step S3, the aeration rate of the nano-aeration device is 0.5-1.0 L / min·m², and the biofilm thickness on the MABR membrane surface is 0.5-2.0 mm.

10. The energy-saving and carbon-reducing ex-situ treatment method of recirculating aquaculture wastewater according to claim 6, characterized in that: In step S4, the planting density of emergent plants (401) in the fourth area is 8-12 plants / m², and the coverage of submerged plants (402) in the fourth area is 30%-50%.

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