Energy-saving and carbon-reducing ectopic treatment system and method for circulating aquaculture wastewater

Abstract

The invention relates to the technical field of aquaculture wastewater treatment, and discloses a circulating aquaculture wastewater energy-saving carbon-reducing ex-situ treatment system and method.The system comprises four treatment areas which are connected in series, and the four treatment areas are sequentially and respectively a wetland purification area, a three-dimensional ecological purification area, a membrane biological treatment area and an ecological conservation purification area from left to right; according to the system, the wetland purification area is used for building a filtering and anaerobic environment, the three-dimensional ecological purification area is designed to serve as a facultative environment, the aerobic biochemical treatment effect is improved through the membrane ecological purification area, finally, deep purification and adjustment are conducted through the ecological conservation area, and effluent returns to a culture pond again for reuse; the pollution load in the aquaculture process is continuously reduced through overall operation of the system, and the technical purposes that water quality is guaranteed under the condition that circulating water is not interrupted in aquaculture, polluted water is treated, and the aquaculture requirement can be continuously met are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of aquaculture wastewater treatment, and in particular to an energy-saving and carbon-reducing ex-situ treatment system and method for circulating aquaculture wastewater. Background Art

[0002] Currently, much of the wastewater generated by aquaculture is discharged untreated. After a season, the wastewater is directly discharged, then treated by drying the pond and solidifying the bottom mud before clean water is introduced to the next aquaculture cycle. This method of aquaculture not only leaves the polluted water untreated, but also affects the taste and quality of the fish and aquatic products raised in polluted water. In severe cases, it can cause fish disease or even death.

[0003] In existing technologies, a small number of concentrated aquaculture areas may employ aeration to increase oxygen levels in the water, or use small amounts of water circulation to mitigate the deterioration of stagnant water quality. However, these measures fail to address the specific characteristics of aquaculture wastewater and effectively reduce the pollution load, making them of little significance in alleviating environmental pollution, improving water quality, or enhancing the quality of aquatic products. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In response to the shortcomings of the existing technology, the present invention provides a circulating aquaculture wastewater energy-saving and carbon-reduction ex situ treatment system and method. Through the overall operation of the system, the pollution load in the aquaculture process is continuously reduced, and the technical problems of ensuring water quality in aquaculture without interrupting the circulating water, treating polluted water, and sustainably meeting aquaculture needs are solved.

[0006] (2) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A recirculating aquaculture wastewater energy-saving and carbon-reduction ex situ treatment system, comprising four treatment zones connected in series, namely, 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;

[0009] 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 material, a plurality of first-area emergent plants are arranged on the biological filter material, a lower water inlet hole is opened below the inlet baffle, and an upper water outlet hole is opened above the outlet baffle;

[0010] The three-dimensional ecological purification area includes floating tubes floating on the water surface, a floating plant support net is set in the rectangular area formed by the floating tubes, a plurality of second-area floating plants are set in the floating plant support net, and microbial biofilms are symmetrically set on the left and right sides of the rectangular area formed by the floating tubes;

[0011] The membrane biological treatment area includes a MABR membrane aeration biofilm reactor, and a third area of submerged plants is arranged below the MABR membrane aeration biofilm reactor;

[0012] The ecological conservation and purification area includes a fourth region of emergent plants arranged on the periphery, and a fourth region of submerged plants is arranged in the middle area of the fourth region of emergent plants.

[0013] Furthermore, the wetland purification area degrades pollutants through anaerobic digestion through adsorption by the biological filter material, attachment, reproduction and decomposition of microorganisms in the water, and absorption and decomposition by the roots of emergent plants in the first area; the biological filter material is a porous biological filter material.

[0014] Furthermore, the three-dimensional ecological purification zone decomposes pollutants through the absorption and decomposition by the roots of floating plants in the second area, and the attachment and reproduction of microorganisms, and further decomposes pollutants through the absorption and decomposition by plant roots and the attachment and reproduction of microorganisms.

[0015] Furthermore, the membrane biological treatment zone performs nano-aeration through the MABR membrane aeration biofilm reactor to provide an aerobic environment, and further enhances the decomposition of pollutants through microorganisms and submerged plants in the third zone.

[0016] Furthermore, the ecological conservation and purification area further purifies water quality through the emergent plants in the fourth area and the submerged plants in the fourth area, thereby improving water transparency and eco-friendliness.

[0017] The entire S1-S4 treatment process does not require the addition of chemical agents. The system energy consumption is concentrated in the nano-aeration link, and the electricity consumption per ton of water is ≤0.15kWh.

[0018] In order to achieve the above object, the present invention also provides the following technical solutions:

[0019] A method for ex situ treatment of circulating aquaculture wastewater for energy conservation and carbon reduction, which is used to use the above-mentioned ex situ treatment system for circulating aquaculture wastewater for energy conservation and carbon reduction, comprises the following steps:

[0020] S1. Wetland anaerobic purification treatment: Wastewater containing pollutants is evenly distributed through the lower water inlet holes and introduced into the wetland purification area. The wastewater is then passed through the biological filter media for physical adsorption, decomposed by anaerobic microorganisms in the water, and absorbed by the roots of the emergent plants in the first area, removing suspended solids, nitrate nitrogen, and chemical oxygen demand.

[0021] S2. Three-dimensional ecological facultative treatment: The effluent from the wetland purification area is introduced into the three-dimensional ecological purification area through the upper effluent holes. Pollutants are absorbed by the roots of floating plants in the second area and degraded by microbial biofilm attachment. An oxygen-deficient environment is formed by the growth and coverage of water surface plants to further reduce nitrogen, phosphorus, and organic pollutants.

[0022] S3. Membrane biological aerobic treatment: Oxygen is supplied to the water body through the nano-aeration device of the MABR membrane aeration biological membrane reactor. Combined with the purification effect of submerged plants in the third area, ammonia nitrogen and chemical oxygen demand are intensively decomposed in an aerobic environment.

[0023] S4. Ecological conservation and purification treatment: The treated water is continuously introduced into the ecological conservation and purification area. The ecological synergy of emergent plants and submerged plants in the fourth area improves the water quality transparency and ecological friendliness, and finally it is reused in the aquaculture system.

[0024] Further, in the step S1, the emergent plants in the first area are canna, cattail or calamus, and the height of the filler layer is 0.8 - 1.2 meters.

[0025] Further, in the step S2, the floating plants in the second area are water hyacinth, myriophyllum or hydrocotyle vulgaris, and the microbial biofilm attachment is made of polyethylene or polypropylene mesh material.

[0026] Further, in the step S3, the aeration volume of the nano-aeration device is 0.5 - 1.0 L / min·m 2 , and the aeration oxygen supply efficiency is 3 - 4 times that of general aeration equipment. The thickness of the biofilm on the MABR membrane surface is 0.5 - 2.0 mm.

[0027] Further, in the step S4, the planting density of the emergent plants in the fourth area is 8 - 12 plants / m 2 , and the coverage rate of the submerged plants in the fourth area is 30% - 50%.

[0028] (III) Beneficial effects

[0029] Compared with the prior art, the present invention provides a system and method for energy-saving and carbon-reducing off-site treatment of circulating aquaculture wastewater, having the following beneficial effects:

[0030] 1. Through the four-stage series treatment of wetland purification area → three-dimensional ecological area → membrane biological treatment area → ecological conservation area, the system forms a closed-loop water circulation system. Test data shows that after the full-process treatment, the ammonia nitrogen removal rate of the water body reaches 92%, the total phosphorus removal rate is 87%, and the dissolved oxygen is maintained above 5 mg / L. The unique MABR membrane aeration technology improves the water body circulation utilization rate to 85%, saving 30% of water compared with the traditional system.

[0031] 2. The system adopts a gravity flow design (with a 40% reduction in energy consumption) combined with a nano-aeration technology (with an energy consumption only 1 / 5 of that of traditional aeration). The annual power consumption of the photovoltaic-driven water pump does not exceed 1500 degrees, and the CO2 emission reduction reaches 2.3 tons / year. The microbial film hanging technology replaces 60% of the mechanical filtration equipment, further reducing energy consumption.

[0032] 3. The biological filter media (with a service life of more than 5 years) adopted by the system and the self-balancing ecological community form a stable purification system, and only the floating pipe array and membrane components need to be inspected quarterly. The Internet of Things sensors monitor water quality parameters in real time, with a failure rate of less than 0.5 times / year, reducing the maintenance man-hours by 80% compared with traditional systems.

[0033] 4. The ecological conservation area of the system plants water bamboo (yielding 800 kg per mu) and water celery (with 4 crops per year). Calculated at the current market price, the treatment system can generate an annual income of 12,000 - 18,000 yuan per 1000 m 2 At the same time, the formed aquatic plant community provides spawning grounds for 12 species of local fish, and the biodiversity index is increased by 2.3 times. Description of the Drawings

[0034] Figure 1 It is a schematic diagram of an energy-saving and carbon-reducing off-site treatment system for circulating aquaculture wastewater according to the present invention;

[0035] Figure 2 It is a schematic diagram of the wetland purification area in an energy-saving and carbon-reducing off-site treatment system for circulating aquaculture wastewater according to the present invention;

[0036] Figure 3 It is the front view and top view schematic diagrams of the three-dimensional ecological purification area in an energy-saving and carbon-reducing off-site treatment system for circulating aquaculture wastewater according to the present invention;

[0037] Figure 4 It is a schematic diagram of the membrane biological treatment area in an energy-saving and carbon-reducing off-site treatment system for circulating aquaculture wastewater according to the present invention;

[0038] Figure 5 It is a schematic diagram of the ecological conservation and purification area in an energy-saving and carbon-reducing off-site treatment system for circulating aquaculture wastewater according to the present invention;

[0039] In the figure: 1. Wetland purification area; 101. Inlet baffle; 102. Outlet baffle; 103. Biological filter media; 104. Emergent plants in the first area; 105. Lower inlet hole; 106. Upper outlet hole; 2. Three-dimensional ecological purification area; 201. Floating pipe; 202. Floating plant support net; 203. Floating plants in the second area; 204. Microbial film hanging; 3. Membrane biological treatment area; 301. MABR membrane aeration biofilm reactor; 302. Submerged plants in the third area; 4. Ecological conservation and purification area; 401. Emergent plants in the fourth area; 402. Submerged plants in the fourth area. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Embodiment 1:

[0042] See also Figures 1-5 This embodiment provides an energy-saving and carbon-reducing ex situ treatment system for recirculating aquaculture wastewater. The system includes four treatment areas connected in series, namely, from left to right, wetland purification area 1, three-dimensional ecological purification area 2, membrane biological treatment area 3, and ecological conservation purification area 4.

[0043] The wetland purification area 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 a biological filter material 103. A plurality of first-region emergent plants 104 are arranged on the biological filter material 103. A lower water inlet hole 105 is provided below the inlet baffle 101, and an upper water outlet hole 106 is provided above the outlet baffle 102. The wetland purification area 1 degrades pollutants through anaerobic digestion through adsorption by the biological filter material 103, attachment, reproduction and decomposition by microorganisms in the water, and absorption and decomposition by the roots of the first-region emergent plants 104. The biological filter material 103 is porous.

[0044] The three-dimensional ecological purification zone 2 includes floating tubes 201 floating on the water surface. A floating plant support net 202 is set within the rectangular area formed by the floating tubes 201. A plurality of second-area floating plants 203 are set within the floating plant support net 202. Microbial biofilms 204 are symmetrically arranged on the left and right sides of the rectangular area formed by the floating tubes 201. The three-dimensional ecological purification zone 2 decomposes pollutants through root absorption and decomposition by the second-area floating plants 203, attachment and reproduction of microorganisms on biofilms, and further decomposition by plant roots and attachment and reproduction of microorganisms on biofilms.

[0045] Membrane biological treatment zone 3 includes a MABR membrane aeration biofilm reactor 301, with a third zone of submerged macrophytes 302 disposed below the MABR membrane aeration biofilm reactor 301. Membrane biological treatment zone 3 utilizes nano-aeration through the MABR membrane aeration biofilm reactor 301 to provide an aerobic environment, further enhancing the decomposition of pollutants through microorganisms and the third zone of submerged macrophytes 302.

[0046] The ecological conservation and purification area 4 includes the emergent plants 401 in the fourth area arranged on the periphery, and the submerged plants 402 in the fourth area are arranged in the middle area of the emergent plants 401 in the fourth area; the ecological conservation and purification area 4 further purifies the water quality through the emergent plants 401 in the fourth area and the submerged plants 402 in the fourth area, improving the water transparency and ecological friendliness.

[0047] Embodiment 2:

[0048] This embodiment provides a method for energy-saving and carbon-reducing off-site treatment of circulating aquaculture wastewater, which is used for a system for energy-saving and carbon-reducing off-site treatment of circulating aquaculture wastewater in Embodiment 1, that is, the working principle of the system for energy-saving and carbon-reducing off-site treatment of circulating aquaculture wastewater, including the following steps:

[0049] S1. Wetland anaerobic purification treatment: The wastewater containing pollutants is evenly distributed and introduced into the wetland purification area 1 through the lower water inlet hole 105, so that the wastewater successively passes through the biological filter material 103 for physical adsorption, decomposition by anaerobic microorganisms in the water and absorption by the roots of the emergent plants 104 in the first area, removing suspended solids, nitrate nitrogen and chemical oxygen demand.

[0050] S2. Three-dimensional ecological facultative treatment: The effluent from the wetland purification area is introduced into the three-dimensional ecological purification area 2 through the upper water outlet hole 106, and the pollutants are degraded through the root absorption of the floating plants 203 in the second area and the microbial film hanging 204. An facultative environment is formed through the growth and coverage of the water surface plants, further reducing nitrogen, phosphorus and organic pollutants.

[0051] 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, and combined with the purification effect of the submerged plants 302 in the third area, ammonia nitrogen and chemical oxygen demand are intensively decomposed in an aerobic environment.

[0052] S4. Ecological conservation and purification treatment: The treated water is continuously introduced into the ecological conservation and purification area 4, and the water transparency and ecological friendliness are improved through the ecological synergy of the emergent plants 401 in the fourth area and the submerged plants 402 in the fourth area, and finally recycled to the aquaculture system.

[0053] In the above embodiment, in step S1, the emergent plants 104 in the first area are canna, cattail or calamus, and the height of its filler layer is 0.8 - 1.2 meters; in step S2, the floating plants 203 in the second area are water hyacinth, myriophyllum or pennywort, and the microbial film hanging 204 is a polyethylene or polypropylene mesh material; in step S3, the aeration volume of the nano-aeration device is 0.5 - 1.0 L / min·m 2 , and the aeration oxygen supply efficiency is 3 - 4 times that of general aeration equipment, and the thickness of the biofilm on the surface of the MABR membrane is 0.5 - 2.0 mm; in step S4, the planting density of the emergent plants 401 in the fourth area is 8 - 12 plants / m2 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. The system energy consumption is concentrated in the nano-aeration process, and the power consumption per ton of water is ≤0.15kWh.

[0054] In summary, the system utilizes the wetland purification zone to create a filtration and anaerobic environment, designs a three-dimensional ecological purification zone as an aerobic 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. The specific advantages are reflected in the following four points:

[0055] 1. This system utilizes a four-stage cascade treatment process: wetland purification zone, three-dimensional ecological zone, membrane biological treatment zone, and ecological conservation zone, creating a closed-loop water circulation system. Test data shows that after the full treatment process, the ammonia nitrogen removal rate in the water reaches 92%, the total phosphorus removal rate reaches 87%, and the dissolved oxygen level is maintained above 5 mg / L. The unique MABR membrane aeration technology increases the water recycling rate to 85%, saving 30% water compared to traditional systems.

[0056] 2. This system utilizes a gravity flow design (reducing energy consumption by 40%) combined with nano-aeration technology (consuming only one-fifth the energy of traditional aeration). The photovoltaic-powered water pump consumes no more than 1,500 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.

[0057] 3. The system utilizes biofilter media (with a service life of over five years) and a self-balancing ecological community to form a stable purification system, requiring only quarterly inspections of the floating tube array and membrane components. IoT sensors monitor water quality parameters in real time, resulting in a failure rate of less than 0.5 events per year, reducing maintenance hours by 80% compared to traditional systems.

[0058] 4. The ecological conservation area used by this system is planted with wild rice stem (800kg per mu) and water celery (4 crops per year). According to the current market price, the yield per 1000m 2 The treatment system can generate an annual income of 12,000 to 18,000 yuan. The resulting aquatic plant community provides spawning grounds for 12 native fish species, increasing the biodiversity index by 2.3 times.

[0059] It should be noted that, in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising said element.

[0060] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A circulating aquaculture wastewater energy-saving and carbon-reducing off-site treatment system, characterized in that: The system includes four treatment areas connected in series, which are, in order from left to right, a wetland purification area (1), a three-dimensional ecological purification area (2), a membrane biological treatment area (3), and an ecological conservation purification area (4); The wetland purification area (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). Above the biological filter media (103), several emergent plants in the first area (104) are provided. 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 area (2) includes floating pipes (201) floating on the water surface. A floating plant support net (202) is arranged in the rectangular area formed by the floating pipes (201). Several floating plants in the second area (203) are arranged in the floating plant support net (202). Microbial biofilms (204) are symmetrically arranged on the left and right sides of the rectangular area formed by the floating pipes (201); The membrane biological treatment area (3) includes a MABR membrane aeration biofilm reactor (301). Submerged plants in the third area (302) are arranged below the MABR membrane aeration biofilm reactor (301); The ecological conservation purification area (4) includes emergent plants in the fourth area (401) arranged on the periphery. Submerged plants in the fourth area (402) are arranged in the middle area of the emergent plants in the fourth area (401).

2. The energy-saving and carbon-reducing off-site treatment system for circulating aquaculture wastewater according to claim 1, wherein: The wetland purification area (1) degrades pollutants through anaerobic digestion by the adsorption of the biological filter media (103), the attachment and reproduction of microorganisms in water, and the absorption and decomposition by the roots of the emergent plants in the first area (104). The biological filter media (103) is porous biological filter media.

3. A cyclic aquaculture wastewater energy-saving and carbon-reducing off-site treatment system according to claim 1, characterized in that: The three-dimensional ecological purification area (2) decomposes pollutants through the absorption and decomposition by the roots of the floating plants in the second area (203), the attachment and reproduction of microbial biofilms, and further through the absorption and decomposition by plant roots and the attachment and reproduction of microbial biofilms.

4. The energy-saving and carbon-reducing off-site treatment system for circulating aquaculture wastewater according to claim 1, wherein: The membrane biological treatment area (3) performs nano-aeration through the MABR membrane aeration biofilm reactor (301) to provide an aerobic environment, and further strengthens the decomposition of pollutants through microorganisms and the submerged plants in the third area (302).

5. The energy-saving and carbon-reducing off-site treatment system for circulating aquaculture wastewater according to claim 1, wherein: The ecological conservation purification area (4) further purifies the water quality, improves the water transparency and ecological friendliness through the emergent plants in the fourth area (401) and the submerged plants in the fourth area (402).

6. A method for energy-saving and carbon-reducing off-site treatment of circulating aquaculture wastewater, which is used for a system for energy-saving and carbon-reducing off-site treatment of circulating aquaculture wastewater according to any one of claims 1-5, characterized in that: It includes the following steps: S1. Wetland anaerobic purification treatment: The wastewater containing pollutants is evenly distributed and introduced into the wetland purification area (1) through the lower inlet hole (105), so that the wastewater sequentially passes through the biological filter media (103) for physical adsorption, decomposition by anaerobic microorganisms in water, and absorption by the roots of the emergent plants in the first area (104) 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 (2) through the upper effluent holes (106), and the pollutants are absorbed by the roots of the floating plants (203) in the second area and degraded by the microbial biofilm (204). The water surface is covered by the growth of plants 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 area, and ammonia nitrogen and chemical oxygen demand are strongly decomposed in an aerobic environment. S4. Ecological conservation and purification treatment: The treated water is continuously introduced into the ecological conservation and purification area (4), and the water quality transparency and ecological friendliness are improved through the ecological synergy of the emergent plants (401) and the submerged plants (402) in the fourth area, and finally recycled to the aquaculture system.

7. A method for energy-saving carbon reduction and off-site treatment of circulating aquaculture wastewater according to claim 6, characterized in that: In the step S1, the emergent plants (104) in the first area are canna, cattail or calamus, and the height of the filler layer is 0.8 - 1.2 meters.

8. A method for energy-saving carbon reduction and off-site treatment of circulating aquaculture wastewater according to claim 6, characterized in that: In the step S2, the floating plants (203) in the second area are water hyacinth, water sprite or pennywort, and the microbial biofilm (204) is made of polyethylene or polypropylene mesh material.

9. A method for energy-saving carbon reduction and off-site treatment of circulating aquaculture wastewater according to claim 6, characterized in that: In the step S3, the aeration volume of the nano-aeration device is 0.5-1.0 L / min·m 2 , and the aeration oxygen supply efficiency is 3 to 4 times that of general aeration equipment, and the thickness of the biofilm on the MABR membrane surface is 0.5-2.0 mm.

10. A method for energy-saving and carbon-reducing off-site treatment of circulating aquaculture wastewater according to claim 6, characterized in that: In the step S4, the planting density of the emergent plants (401) in the fourth area is 8 - 12 plants / m 2 , and the coverage rate of the submerged plants (402) in the fourth area is 30% - 50%.

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