Culture tail water treatment integrated system based on BF-MABR

Abstract

The invention discloses a BF-MABR-based culture tail water treatment integrated system which comprises a pretreatment unit and an efficient treatment unit which are arranged in a culture pond, the bottom of the pretreatment unit is communicated with the bottom of the efficient treatment unit, and the pretreatment unit comprises a grating area and a brush area from front to back; wherein the grating area is composed of a plurality of groups of gratings, and the brush area is composed of a plurality of groups of ecological brushes fixed on a rope and is perpendicular to the water flow direction; the efficient treatment unit comprises a combination of a plurality of groups of membrane aeration biological membrane assemblies, biological filler, an air supply unit and aquatic plants, and the plurality of groups of membrane aeration biological membrane assemblies are arranged in parallel and are vertical to the water flow direction; by coupling the biological filler and the membrane aeration bio-membrane reactor, the amount of attached microorganisms is increased, the membrane pollution problem is relieved, the impact load resistance is enhanced, meanwhile, stable and efficient treatment of aquaculture tail water is achieved, the environmental pressure caused by excessive discharge of the aquaculture tail water in a region is relieved, and improvement of the water environment quality is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of aquaculture tail water treatment, and in particular to an aquaculture tail water treatment integrated system based on BF-MABR. Background Art

[0002] With the rapid development of aquaculture, the problem of aquaculture tailwater discharge has become increasingly prominent in the process of intensive and high-density aquaculture, seriously restricting the improvement of regional water environment quality. The large amount of residues of new pollutants such as antibiotics in the water environment leads to bioaccumulation and high toxicity to non-target organisms, threatening the biodiversity and function of adjacent aquatic ecosystems, and may cause bacteria to produce antibiotic resistance genes, threatening human health and other problems.

[0003] At present, many provinces and cities across the country have successively formulated and issued aquaculture tailwater discharge standards, and carried out aquaculture tailwater treatment technology research and application engineering demonstration. The "Technical Specifications for Ecological Treatment of Pond Aquaculture Tailwater" (DB32 / T 4725-2024), "Technical Specifications for Ecological Treatment of Aquaculture Tailwater" (DB3401 / T 203-2020), and "Technical Specifications for Treatment of Freshwater Pond Aquaculture Tailwater" (DB33 / T 2288-2020) stipulate the main facilities, process flow, tailwater treatment facility area, operation management and discharge water quality of aquaculture tailwater treatment technology. Traditional pond aquaculture tailwater ecological treatment processes, such as "three ponds and two dams" and "artificial wetlands", are not efficient in treating high-concentration organic pollutants, especially when the density of aquaculture is high. The content of nutrients such as nitrogen and phosphorus in the tailwater is high, and the land area is large and the process cost is high. In addition, different geographical and climatic conditions may affect the effect of the ecological water treatment system, such as poor treatment effect at low temperatures in winter, and the inability of the effluent to meet the standards stably. The Membrane Aeration Bioreactor (MABR) replaces traditional aeration methods with membrane aeration and combines it with biofilm technology to achieve efficient and stable removal of pollutants.

[0004] The patent with publication number CN116813074A discloses a process for treating aquaculture tailwater based on MABR enhanced three-tank two-dam system, which includes a sedimentation zone, a first filtration zone, a MABR biofilm purification zone, a second filtration zone and an ecological purification zone. However, in actual operation, the phosphorus removal effect of this process is limited, and more membrane materials are required, resulting in higher technical costs. The patent with publication number CN219429806U discloses a biological filler for aquaculture water, which can increase the amount of microbial biofilm, make biofilm removal easier, and greatly improve the cultivation efficiency of microbial flora mother liquor. However, in actual operation, the biological filler has poor resistance to shock loads, and will become blocked or aged due to changes in water quality, accumulation of microbial metabolites, etc., which increases energy consumption and affects treatment efficiency.

[0005] The patent with publication number CN116081850A discloses a method for treating aquaculture tailwater, which specifically includes: water distribution in water channels, solid particle sedimentation in sedimentation tanks, MABR enhanced treatment in membrane aeration biological reactors, ecological purification in ecological purification tanks, and discharge of ecological purified water. In actual operation, the hydrophilicity and attached microbial biomass of the aeration membrane in MABR are limited, and biofilm shedding is prone to occur. In addition, the problem of membrane contamination increases the membrane mass transfer resistance, causing the membrane's gas flux to decrease, thereby affecting the oxygen mass transfer capacity. In addition, the characteristics and treatment requirements of aquaculture tailwater in different regions are different, and this method cannot meet the differentiated needs of various application scenarios.

[0006] Therefore, there is an urgent need to develop an integrated aquaculture effluent treatment system based on biological filler-membrane aeration bioreactor (BF-MABR) to efficiently treat aquaculture effluent in different scenarios, effectively remove new pollutants such as antibiotics, alleviate the environmental pressure caused by excessive discharge of aquaculture effluent in the region, and help improve the water environment quality. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide an integrated aquaculture effluent treatment system based on BF-MABR in view of the shortcomings of the above-mentioned prior art. By coupling biological fillers and membrane aeration biofilm reactors, the amount of attached microorganisms is increased, the membrane pollution problem is alleviated, and the ability to resist shock loads is enhanced. By setting up aquatic plant planting areas, new pollutant residues such as antibiotics in aquaculture effluents are effectively removed, thereby achieving stable and efficient treatment of aquaculture effluents, alleviating the environmental pressure caused by excessive discharge of aquaculture effluents in the region, and helping to improve the quality of the water environment.

[0008] The technical solution of the present invention to solve the above technical problems is: an integrated system for aquaculture tailwater treatment based on BF-MABR, comprising a pre-treatment unit and a high-efficiency treatment unit arranged in an aquaculture pond, wherein the bottoms of the pre-treatment unit and the high-efficiency treatment unit are in a communicating state, and the pre-treatment unit comprises a grid area and a brush area from front to back, wherein the grid area is composed of a plurality of groups of grids, and the brush area is composed of a plurality of groups of ecological brushes fixed to ropes, and is perpendicular to the water flow direction; The high-efficiency treatment unit includes a combination of multiple groups of membrane aeration biofilm components, biological fillers, air supply units and aquatic plants, wherein the multiple groups of membrane aeration biofilm components are arranged in parallel and perpendicular to the water flow direction, the biological fillers include curtain-type biological ropes and mixed fillers, wherein the curtain-type biological ropes are laid flat on the surface of the membrane aeration biofilm components and are fixed with nylon ties at certain intervals, and the mixed fillers are filled at the bottom of the high-efficiency treatment unit; the air supply unit supplies air to the membrane aeration biofilm components and the biological fillers through an air supply pipeline.

[0009] The present invention further defines the scheme: Preferably, the membrane aeration biofilm assembly includes membrane filaments and a membrane assembly frame, which are perpendicular to the water flow direction as a whole, and multiple groups of membrane aeration biofilm assemblies are arranged in parallel. The membrane filaments are hollow fiber membranes or tubular membranes, and are fixed on the membrane assembly frame. When the oxygen in the membrane is lower than the bubble point pressure, it is transferred to the biofilm on the surface of the membrane material through the membrane pores. At the same time, under the disturbance of external liquid, pollutants in the liquid phase pass through the biofilm gaps into the interior of the biofilm, and dephosphorization and nitrogen removal are achieved through the metabolism of the microbial flora.

[0010] Preferably, the membrane aeration biofilm assembly adopts a closed-end aeration method with air intake at one end, and the other end discharges the remaining waste gas in the membrane cavity at regular intervals.

[0011] Preferably, the air supply unit is connected in series with the membrane aeration biofilm assembly via an air supply pipeline, and the air supply pipeline is provided with a control valve for independently controlling the air supply amount of each membrane aeration biofilm assembly.

[0012] Preferably, the aquatic plants include submerged plants, floating leaf plants and emergent plants.

[0013] Preferably, the submerged plants include one or several combinations of Vallisneria, Hydrilla, Duckweed, Elodea, Water Chestnut, Potamogeton, Microdentata, and Foxtail Algae; the floating-leaf plants include one or several combinations of Water Lily, Water Chestnut, Euryale, Nymphoides, Water Chestnut, and Pennisetum; the emergent plants include one or several combinations of Zizania, Evergreen Iris, Cyperus, Aquatic Canna, Cattail, and Acorus;

[0014] Preferably, the mixed filler is a mixture of volcanic rock and blast furnace slag, which is filled at the bottom of the high-efficiency treatment unit to exert physical adsorption and microbial degradation effects and effectively remove new pollutants such as antibiotics.

[0015] Preferably, the grid area includes multiple groups of grids, and the grids are matched with coarse and fine precision, including coarse grids and fine grids, wherein the gap between the coarse grid bars is 15-30mm, and the gap between the fine grid bars is 2-15mm, which can be determined according to the actual water quality of the aquaculture effluent and the amount of water to be treated, so as to intercept floating objects and suspended particles and ensure the treatment effect of the subsequent treatment unit.

[0016] Preferably, the brush area is composed of multiple groups of ecological brushes fixed to polyethylene ropes or stainless steel wires at intervals of 15-30 cm, which are perpendicular to the water flow direction. The brushes are used to remove suspended matter in the filtered water and cultivate microorganisms to reduce nitrogen and phosphorus.

[0017] The beneficial effects of the present invention are: The configuration ratio and pattern of the aquatic plants of the present invention are determined according to the actual water quality characteristics of the aquaculture tail water. The hydraulic retention time of the high-efficiency treatment unit is ≤8 hours. By constructing the pre-treatment unit and the high-efficiency treatment unit, the new pollutants such as organic matter, ammonia nitrogen, total phosphorus and antibiotics can be effectively removed. By coupling the biological filler with the membrane aeration biofilm assembly, the membrane pollution problem can be significantly improved, the short-circuit phenomenon can be weakened, the dead zone ratio can be reduced by 5%-15%, the effective volume ratio can be increased by 1.5-2.3 times, and the amount of attached microorganisms can be significantly increased, the membrane pollution problem can be effectively solved, the influence of the large coefficient of variation of the water volume of the aquaculture tail water can be reduced, and the impact load resistance can be enhanced. By differentially assembling each treatment unit, the needs of different aquaculture methods, tail water quality characteristics, actual on-site conditions and other application scenarios can be met, the environmental pressure caused by the excessive discharge of aquaculture tail water in the region can be alleviated, and the water environment quality can be improved. The effluent from the integrated aquaculture effluent treatment system based on BF-MABR of the present invention can reach a permanganate index of ≤15mg / L, a total phosphorus of ≤0.4mg / L, a suspended solids of ≤40mg / L, and a total nitrogen of ≤3mg / L, which meets the discharge requirements of aquaculture effluent in freshwater areas, and can effectively remove new pollutants such as antibiotics, ensure biodiversity, and protect food safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a process flow chart of tail water treatment of the present invention; Figure 2 is a cross-sectional schematic diagram of the pre-processing unit; Figure 3 It is a schematic diagram of the plane of the efficient processing unit; Figure 4 Schematic diagram of membrane aeration biofilm assembly. DETAILED DESCRIPTION

[0019] The present invention can be better understood with reference to the following examples. Example

[0020] This embodiment is used in a certain fish pond with a breeding area of ​​about 2,400 mu. Before the transformation, there was no effective treatment measure for the breeding tailwater, which was directly discharged into the surrounding ditches. The effluent permanganate index was 9.5-36.4 mg / L, total nitrogen was 1.19-11.5 mg / L, and total phosphorus was 0.09-2.65 mg / L. The average concentrations of permanganate index, total nitrogen, and total phosphorus were 23.17 mg / L, 7.47 mg / L, and 0.86 mg / L, respectively. The problem of tailwater exceeding the standard was prominent and could not meet the standard. Based on the above actual needs, this embodiment provides an integrated system for aquaculture tailwater treatment based on BF-MABR, such as Figure 1-4 As shown, it includes a pre-treatment unit 01 and a high-efficiency treatment unit 02 arranged in the aquaculture pond. The aquaculture tailwater enters the pre-treatment unit through the lifting pump. The pre-treatment unit includes 2 groups of screens 011 and 10 groups of ecological brushes 012 from front to back. The screen precision adopts coarse and fine matching. The gap between the coarse screen bars is 20mm, and the gap between the fine screen bars is 8mm. The ecological brushes are fixed on the polyethylene rope every 15cm, perpendicular to the water flow direction, to intercept and remove large suspended particles such as bait residues and excrement; The effluent from the pre-treatment unit enters the high-efficiency treatment unit, which deeply absorbs and decomposes organic matter, ammonia nitrogen, total phosphorus, etc. The high-efficiency treatment unit includes multiple groups of membrane aeration biofilm components 03, biological fillers, air supply units and aquatic plants. The multiple groups of membrane aeration biofilm components are arranged in parallel and perpendicular to the water flow direction. The membrane aeration biofilm components include membrane filaments 021 and membrane component racks 026. The membrane filaments are hollow fiber membranes and are fixed on the membrane component racks. The biological fillers are curtain-type biological ropes 022, volcanic rocks and blast furnace slag. The curtain-type biological ropes 022 are laid flat on the surface of the membrane filaments 021 and fixed with cable ties every 40 cm. The volcanic rocks and blast furnace slag are mixed and filled at the bottom of the high-efficiency treatment unit. The air supply unit 023 supplies air to the membrane aeration biofilm assembly and the biological filler through the air supply pipeline 025. At the same time, the air supply unit is connected in series with the membrane aeration biofilm assembly through the air supply pipeline, and the air supply pipeline connected to the membrane aeration biofilm assembly is provided with a control valve 024 for independently controlling the air supply amount of each membrane aeration biofilm assembly. Aquatic plants include submerged plants, floating leaf plants and emergent plants. The submerged plants are a combination of Vallisneria, Hydrilla, Duckweed and Elodea; the floating leaf plants are a combination of Water Lily, Water Chestnut and Euryale; and the emergent plants are a combination of Cattail and Acorus.

[0021] After treatment by the above-mentioned device, the effluent permanganate index is ≤15mg / L, total phosphorus is ≤0.4mg / L, suspended solids is ≤40mg / L, and total nitrogen is ≤3mg / L, meeting the Class I standard for aquaculture effluent in freshwater areas in the "Pond Aquaculture Tailwater Discharge Standard" of Jiangsu Province (DB32 / 4043-2021), and the removal rate of antibiotics and other substances reaches 45.2%. Example

[0022] This embodiment is used in a fish pond with a breeding area of ​​about 3750 mu. Before the transformation, there was no effective treatment measure for the breeding tail water, and the permanganate index was 25~ 50mg / L, total phosphorus 1.2-1.5mg / L, total nitrogen 10-12mg / L, the maximum exceeded the standard by 2 times, 1.88 times, and 2 times respectively. The effluent exceeded the standard frequently and the multiple exceeded the standard by a large amount. The aquaculture tail water contained new pollutants such as antibiotics. Based on the above actual needs, this embodiment provides an integrated aquaculture tail water treatment system based on BF-MABR, such as Figure 1-4 As shown, it includes a pre-treatment unit 01 and a high-efficiency treatment unit 02 arranged in the aquaculture pond. The aquaculture tailwater enters the pre-treatment unit through the lifting pump. The pre-treatment unit includes 3 groups of grilles 011 and 8 groups of ecological brushes 012 from front to back. The grille precision adopts coarse and fine matching. The gap between the coarse grille bars is 15mm, and the gap between the fine grille bars is 10mm. The ecological brushes are fixed on the stainless steel wire every 30cm, perpendicular to the water flow direction, to intercept and remove large suspended particles such as bait residues and excrement; The effluent from the pre-treatment unit enters the high-efficiency treatment unit, which deeply adsorbs and decomposes organic matter, ammonia nitrogen, total phosphorus, etc. The high-efficiency treatment unit includes multiple groups of membrane aeration biofilm components 03, biological fillers, air supply units and aquatic plants 04. The multiple groups of membrane aeration biofilm components are arranged in parallel and perpendicular to the water flow direction. The membrane aeration biofilm components include membrane filaments 021 and membrane component racks 026. The membrane filaments are hollow fiber membranes and are fixed on the membrane component racks. The biological fillers are curtain-type biological ropes, volcanic rocks and blast furnace slag. The curtain-type biological ropes 022 are laid flat on the surface of the membrane filaments 021 and are fixed with cable ties every 40 cm. The curtain-type biological ropes are used as microbial carriers. Coupling with membrane aeration biofilms can significantly increase the concentration of microorganisms, improve oxygen utilization and treatment efficiency, and have strong impact load resistance. Volcanic rocks and blast furnace slag are mixed and filled at the bottom of the high-efficiency treatment unit to exert physical adsorption and microbial degradation effects, and effectively remove new pollutants such as antibiotics. The air supply unit 023 supplies air to the membrane aeration biofilm assembly 02 and the biological filler through the air supply pipeline 025. At the same time, the air supply unit is connected in series with the membrane aeration biofilm assembly through the air supply pipeline, and the air supply pipeline connected to the membrane aeration biofilm assembly is provided with a control valve 024 for independently controlling the air supply amount of each membrane aeration biofilm assembly. Aquatic plants include submerged plants, floating leaf plants and emergent plants. Among them, the submerged plants are a combination of water chestnuts, Malaysian pondweed, micro-toothed pondweed and spike-flowered foxtail algae; the floating leaf plants are a combination of water chestnuts, water lilies and pennywort; the emergent plants are a combination of wild rice stems, evergreen iris, Cyperus rotundus and aquatic canna.

[0023] After the aquaculture tail water is treated by the above steps, the permanganate index of the effluent is ≤15mg / L, the total phosphorus is ≤0.4mg / L, the suspended solids is ≤40mg / L, and the total nitrogen is ≤3mg / L, meeting the Class I standard for freshwater aquaculture effluent discharge in Jiangsu Province's "Pond Aquaculture Effluent Discharge Standard" (DB32 / 4043-2021), and the antibiotic removal rate reaches 52.8%.

[0024] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. An integrated system for aquaculture tailwater treatment based on BF-MABR, comprising a pre-treatment unit and a high-efficiency treatment unit arranged in an aquaculture pond, characterized in that: The bottoms of the pre-treatment unit and the high-efficiency treatment unit are in a connected state. The pre-treatment unit includes a grille area and a brush area from front to back, wherein the grille area is composed of multiple groups of grilles, and the brush area is composed of multiple groups of ecological brushes fixed to ropes and perpendicular to the water flow direction; The high-efficiency treatment unit includes a combination of multiple groups of membrane aeration biofilm components, biological fillers, air supply units and aquatic plants, wherein the multiple groups of membrane aeration biofilm components are arranged in parallel and perpendicular to the water flow direction, the biological fillers include curtain-type biological ropes and mixed fillers, wherein the curtain-type biological ropes are laid flat on the surface of the membrane aeration biofilm components and are fixed with nylon ties at certain intervals, and the mixed fillers are filled at the bottom of the high-efficiency treatment unit; the air supply unit supplies air to the membrane aeration biofilm components and the biological fillers through an air supply pipeline.

2. A BF-MABR-based aquaculture tailwater treatment integrated system according to claim 1, characterized in that: The membrane aeration biological membrane component comprises membrane filaments and a membrane component frame. The membrane filaments are hollow fiber membranes or tubular membranes and are fixed on the membrane component frame.

3. The integrated system for aquaculture tailwater treatment based on BF-MABR according to claim 1, characterized in that: The membrane aeration biofilm component adopts a closed-end aeration mode with air intake at one end, and the other end discharges the remaining waste gas in the membrane cavity at regular intervals.

4. The integrated system for aquaculture tailwater treatment based on BF-MABR according to claim 1, characterized in that: The air supply unit is connected in series with the membrane aeration biofilm assembly via an air supply pipeline, and the air supply pipeline is provided with a control valve for independently controlling the air supply amount of each membrane aeration biofilm assembly.

5. The integrated system for aquaculture tailwater treatment based on BF-MABR according to claim 1, characterized in that: The aquatic plants include submerged plants, floating leaf plants and emergent plants.

6. The integrated system for aquaculture tailwater treatment based on BF-MABR according to claim 5, characterized in that: The submerged plants include one or several combinations of Vallisneria, Hydrilla, Duckweed, Elodea, Water Chestnut, Potamogeton, Microdentata, and Foxtail Grass; the floating-leaf plants include one or several combinations of Water Lily, Water Chestnut, Euryale, Nymphoides, Water Chestnut, and Pennisetum; the emergent plants include one or several combinations of Zizania, Evergreen Iris, Cyperus, Aquatic Canna, Cattail, and Acorus.

7. The integrated system for aquaculture tailwater treatment based on BF-MABR according to claim 1, characterized in that: The mixed filler is a mixture of volcanic rock and blast furnace slag.

8. The integrated system for aquaculture tailwater treatment based on BF-MABR according to claim 1, characterized in that: The grid area includes multiple groups of grids, and the grids are matched with coarse and fine precision, including coarse grids and fine grids, wherein the gap between the coarse grid bars is 15-30mm, and the gap between the fine grid bars is 2-15mm.

9. The integrated system for aquaculture tailwater treatment based on BF-MABR according to claim 1, characterized in that: The brush area is composed of a plurality of groups of ecological brushes fixed to polyethylene ropes or stainless steel wires at intervals of 15-30 cm.

Images