Ecological treatment process and system for removing antibiotics in aquaculture tail water

Abstract

The invention belongs to the technical field of aquaculture tail water treatment, and discloses an ecological treatment process and system for removing antibiotics in aquaculture tail water. The method is used for solving the problems that a traditional ecological tail water treatment mode is not ideal in removal effect on most antibiotics and drug-resistant genes, and the purpose and effect of removing the antibiotics cannot be achieved. According to the scheme, tail water is settled and intercepted through the front end of the ecological ditch; antibiotics in the tail water are removed through an antibiotic removal module arranged at the tail end of the ecological ditch, wherein the antibiotic removal module comprises a metal load type module, suspended filler and an ecological floating island; the tail water passing through the antibiotic removal module is subjected to multi-stage purification through a sedimentation tank, a first filter dam, an aeration tank, a second filter dam and an ecological purification tank.

Description

Technical Field

[0001] The present invention belongs to the technical field of aquaculture tail water treatment, and particularly relates to an ecological treatment process and system for removing antibiotics from aquaculture tail water. Background Art

[0002] With the continuous expansion of the demand for antibiotics, the production of antibiotics in China has been on the rise. In 2020, the production of antibiotics in China reached 223,000 tons, of which the usage of veterinary antibiotics was 3,280 tons. After the use of antibiotics, 30% - 90% will not be metabolized and decomposed by the human body and animals, and will be excreted out of the body in the form of the original drug and enter the environment. In the process of aquaculture, drugs are usually used to prevent and treat related diseases. At present, the commonly used antibiotics include aminoglycosides, tetracyclines, amide alcohols, sulfonamides, and quinolones, etc. Different from other industries, 70% - 80% of the antibiotics used in the aquaculture process will eventually directly enter the water environment and sediment, affecting the water ecosystem. Especially in environmentally sensitive areas such as water source areas, the environmental pollution problem of the aquaculture industry has always been a hot issue of social concern.

[0003] The removal effect of traditional ecological tail water treatment models on most antibiotics and resistance genes is not ideal, and there are currently no relevant discharge standards for antibiotics and resistance genes, resulting in the inability of existing ecological processes to achieve the purpose and effect of removing antibiotics.

[0004] Therefore, there is an urgent need for an ecological treatment process for removing antibiotics from aquaculture tail water. Summary of the Invention

[0005] One or more embodiments of this specification provide an ecological treatment process and system for removing antibiotics from aquaculture tail water. The following technical problems are solved: The removal effect of traditional ecological tail water treatment models on most antibiotics and resistance genes is not ideal, and the purpose and effect of removing antibiotics cannot be achieved.

[0006] To solve the above technical problems, one or more embodiments of this specification are implemented as follows: In a first aspect, one or more embodiments of this specification provide an ecological treatment process for removing antibiotics from aquaculture tail water, including: Sedimentation and interception treatment of the tail water are carried out at the front end of the ecological ditch; The antibiotics in the tail water are removed by an antibiotic removal module arranged at the end of the ecological ditch, wherein the antibiotic removal module includes a metal-loaded module, suspended packing, and an ecological floating island; The tail water passing through the antibiotic removal module is subjected to multi-stage purification by a sedimentation tank, a first filter dam, an aeration tank, a second filter dam, and an ecological purification tank.

[0007] Optionally, the metal-loaded module is BiVO4 supported on activated carbon fibers, and the pollution load is 0.2 - 0.4 g / (m²·d).

[0008] Optionally, the ecological floating island is made by fixing multiple floating bodies made of HDPE through connecting fasteners. An injection-molded hollow planting basket is arranged on the surface of the floating body, and the planting basket is filled with volcanic rock matrix. The roots of vetiver penetrate through the planting basket and contact the suspended packing to form a biofilm-plant synergistic degradation interface.

[0009] Optionally, the suspended packing is made of volcanic rock or activated carbon, and is fixed by nylon ropes. The horizontal spacing is the same as the spacing between the ecological floating islands, and the vertical spacing is 0.5 m. It is fixed below the ecological floating island to form a three-dimensional biofilm attachment space.

[0010] Optionally, the sedimentation tank has a depth of 2.5 - 3.5 m, and artificial aquatic plants are suspended. The length of the artificial aquatic plants is 1.5 m.

[0011] Optionally, an aerator is installed at 30 - 50 cm from the bottom of the aeration tank, and the depth of the tank is 2.5 m.

[0012] Optionally, the depth of the deep water area of the ecological purification tank is 3.0 - 4.0 m, and the depth of the shallow water area is < 1 m. Emergent plants and submerged plants are planted.

[0013] Optionally, the first filter dam is arranged between the sedimentation tank and the aeration tank, and the second filter dam is arranged between the aeration tank and the ecological purification tank. The first filter dam and the second filter dam are steel cage packing structures.

[0014] In a second aspect, one or more embodiments of this specification provide an ecological treatment system for removing antibiotics from aquaculture tail water, including: An ecological ditch section, with a plant interception zone at the front end and connected to an antibiotic removal module at the end; The antibiotic removal module is composed of a metal-loaded module, suspended packing, and an ecological floating island. Among them, the metal-loaded module is detachable and replaceable; A multi-stage purification unit, including a sedimentation tank, a first filter dam, an aeration tank, a second filter dam, and an ecological purification tank. Each unit is connected by gravity flow through a hydraulic gradient.

[0015] Optionally, a diversion retaining wall is arranged between the metal-loaded module and the ecological floating island. The retaining wall enhances the contact efficiency of pollutants with the metal-loaded module, the ecological floating island, and the suspended packing through hydraulic turbulence.

[0016] An ecological treatment process and system for removing antibiotics from aquaculture tail water provided by one or more embodiments of this specification have the following beneficial effects: 1. An ecological treatment process and system for removing antibiotics from aquaculture wastewater achieve efficient removal of antibiotics in the aquaculture wastewater through the synergistic effects of physical adsorption, plant absorption, etc., improve the water ecosystem, and mainly use physical and biological means for treatment, reducing secondary pollution.

[0017] 2. An ecological treatment process and system for removing antibiotics from aquaculture wastewater has a long service life and can operate continuously for 3 - 5 years, ensuring the sustainability of the treatment effect.

[0018] 3. An ecological treatment process and system for removing antibiotics from aquaculture wastewater has a modular component design, and the packing replacement is convenient and fast, greatly reducing the maintenance cost and time.

[0019] 4. An ecological treatment process and system for removing antibiotics from aquaculture wastewater has low energy consumption, low initial investment, and low operating cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present specification or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present specification. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic flow chart of an ecological treatment process and system for removing antibiotics from aquaculture wastewater according to the present invention; Figure 2 It is a process flow chart of an ecological treatment process and system for removing antibiotics from aquaculture wastewater according to the present invention; Figure 3 It is a plan view of an ecological treatment process and system for removing antibiotics from aquaculture wastewater according to the present invention; Figure 4 It is a cross-sectional view of an ecological treatment process and system for removing antibiotics from aquaculture wastewater according to the present invention; Figure 5 It is a node diagram of the antibiotic removal module of an ecological treatment process and system for removing antibiotics from aquaculture wastewater according to the present invention.

[0022] Among them: 1. Metal-loaded module, 2. Retaining wall, 3. Suspended packing, 4. Vetiveria zizanioides, 5. Ecological floating island. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The embodiments of the present specification provide an ecological treatment process and system for removing antibiotics from aquaculture wastewater.

[0024] In order to help those skilled in the art better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0025] The present invention optimizes the problem of low efficiency in removing antibiotics in the traditional "three ponds and two dams" treatment process. An antibiotic removal module is added to the front end of the original "three ponds and two dams" process and the end of the ecological ditch, without increasing the land area and saving land costs.

[0026] The technical solutions provided by the embodiments of this specification are described in detail below with reference to the accompanying drawings.

[0027] Figure 1 The present invention is a flow chart of an ecological management process and system for removing antibiotics from aquaculture tail water.

[0028] S101: Settle and intercept tailwater through the front end of the ecological ditch.

[0029] In one or more embodiments of this specification, the main function of the front end of the ecological ditch is to drain the tail water. During the long-distance flow of the tail water, sedimentation and interception can occur to remove some pollutants. If there are already ecological channels or available drainage channels, ditches, etc. within the scope of the farm land, they can be used through appropriate transformation, such as widening, deepening, silting, etc., to improve the channel storage and drainage capacity. If there are no available channels in the breeding area, the ponds can be connected in series through pipes. A suitable amount of aquatic plants with strong water treatment capabilities are planted along the slopes of the ecological ditch to perform preliminary water purification, such as submerged plants Vallisneria, Hydrilla verticillata, Elodea, etc., floating leaf plants such as water lilies, and emergent plants such as Zizania latifolia, Canna, Iris, etc. are planted around, and the ecological ditch is used to perform preliminary treatment of the aquaculture tail water. In one embodiment, submerged plants, emergent plants and floating leaf plants are planted at the front end of the ecological ditch, with a coverage area of ≥30%, and suspended solid pollutants are removed through the synergistic effect of plant root biofilm and suspended matter interception.

[0030] S102: removing antibiotics from the tail water through an antibiotic removal module provided at the end of the ecological ditch, wherein the antibiotic removal module comprises a metal-loaded module 1 , a suspended filler 3 and an ecological floating island 5 .

[0031] In one or more embodiments of the present specification, the metal-loaded module 1 is BiVO4 supported on activated carbon fibers, with a pollution load of 0.2 - 0.4 g / (m²·d); the ecological floating island 5 is made by fixing multiple floating bodies made of HDPE through connecting fasteners. The surface of the floating body is provided with injection-molded hollow planting baskets filled with volcanic rock matrix. The roots of vetiver penetrate the planting baskets and contact the suspended fillers to form a biofilm-plant synergistic degradation interface; the suspended fillers are made of volcanic rock or activated carbon, fixed by nylon ropes, with the same horizontal spacing as the spacing of the ecological floating islands, and fixed 0.5 m below the ecological floating islands at vertical intervals to form a three-dimensional biofilm attachment space; the tail water enters the antibiotic removal module and passes through the metal-loaded module 1 with BiVO4 supported on activated carbon fibers, the suspended fillers 3, and the ecological floating island 5 in sequence.

[0032] Figure 5 This is a node diagram of the antibiotic removal module of an ecological treatment process and system for removing antibiotics from aquaculture tail water according to the present invention, which will be described in combination with Figure 5 wherein, 1 is the metal-loaded module, 2 is the retaining wall, 3 is the suspended filler, 4 is vetiver, and 5 is the ecological floating island.

[0033] The metal-loaded module 1 is detachable and mainly degrades and removes antibiotics. The removal rates of traditional "three ponds and two dams" for TSS, CODMn, TN, TP, and NH+4-N are 48.1% - 60.7%, 50.4% - 60.7%, 52.5% - 59.2%, 64.2% - 71.5%, and 72.1% - 80.5% respectively, without involving the removal rate of antibiotics. The pollution load of the metal-loaded module 1 for antibiotic removal is 0.2 - 0.4 g / (m2·d). The antibiotic removal rate exceeds 40%. In one embodiment, the specific surface area of the activated carbon fibers of the metal-loaded module 1 is 1200 - 1500 m² / g, the loading thickness of BiVO4 is 10 - 20 cm, the pollution load is 0.2 - 0.4 g / (m²·d), the hydraulic retention time is 2 - 4 hours, and the removal rate of sulfonamide antibiotics is ≥40%.

[0034] In one or more embodiments of the present specification, the suspended filler 3 is made of volcanic rock or modified activated carbon, with a particle size of 1 - 4 mm, a specific surface area of ≥800 m² / g, a porosity of ≥80%, where the proportion of micropores is ≥60% and the proportion of mesopores is 20 - 30%.

[0035] The ecological floating island 5 absorbs antibiotics through the roots of plants. The biofilm on the roots of plants and the metabolic action of microorganisms further decompose these pollutants and convert them into inorganic substances, thereby purifying the water quality. The material of the ecological floating island 5 is HDPE, with side length * side length * thickness of φ1.0 m * 0.5 m * 0.05 m. The number of sets (holes) per square meter: 2 sets / square meter (16 holes / square meter); the size of the planting basket (diameter * height): φ135 mm * 165 mm. One floating island is equipped with 1 planting basket and 1 connecting fastener. The floating island is made of HDPE and connected by screws. The planting basket is an injection-molded hollow flowerpot. The floating islands are fixed by connecting fasteners. The planting basket inside the ecological floating island is concave on both sides. One side is used for planting aquatic plants (vetiver 4), and the other side is closely attached to the suspended packing. The vetiver 4 on the floating island is used to remove ciprofloxacin and TC in the secondary wastewater. The removal rates of the two antibiotics reach 93% and 97% respectively. The suitable planting density of vetiver is 4 - 7 plants / m². The retaining wall 2 is provided with positioning ropes. The positioning ropes can be made of nylon. Installation ropes that extend horizontally and are fixed at both ends are arranged between the positioning ropes. The installation ropes are fixed on the two side chutes. A row of suspended packing is arranged on the installation ropes. The retaining wall 2 can enhance the contact efficiency between pollutants and the metal-loaded module, the ecological floating island and the suspended packing through hydraulic turbulence.

[0036] S103: The tail water passing through the antibiotic removal module is subjected to multi-stage purification by a sedimentation tank, a first filtration dam, an aeration tank, a second filtration dam, and an ecological purification tank.

[0037] Combined with Figure 2 The process flow chart of an ecological treatment process and system for removing antibiotics from aquaculture tail water according to the present invention, Figure 3 The plan view of an ecological treatment process and system for removing antibiotics from aquaculture tail water according to the present invention, Figure 4 The cross-sectional view of an ecological treatment process and system for removing antibiotics from aquaculture tail water according to the present invention will be described.

[0038] In one or more embodiments of the present specification, the main function of the sedimentation tank is to precipitate and remove solid pollutants such as suspended substances, excreta, and residues in the tail water that are insoluble in water, increase the transparency of the water body, enhance the vitality of the water body, and facilitate the photosynthesis of the water body. The depth of the sedimentation tank is 2.5 - 3.5 m. Artificial aquatic plants are suspended in the vertical direction of the water flow near the drainage outlet. The artificial aquatic plants are made of elastic fiber material and have a length of 1.5 m.

[0039] The depth of the aeration tank is 2.5 m, and aerators are installed at a depth of 30 - 50 cm from the bottom. The aerators can be diaphragm disc micro - pore aerators, but are not limited thereto. The aerators carry out artificial oxygenation for the tail water in an anoxic state, or oxygenate the tail water through an intermittent aeration mode. The intermittent aeration mode controls the dissolved oxygen concentration fluctuation ≤ ±0.5 mg / L, accelerates the oxidation and decomposition of organic pollutants, enhances the self - purification ability of the water body, and improves water quality.

[0040] The ecological purification pond is designed as a central - pit - type deep pond (anaerobic pond / deep - water area) and a marginal - shoal - type (facultative pond / aerobic pond / shallow - water area). The depth of the deep pond is 3.0 m - 4.0 m, and the water depth within 3 m from the edge of the shallow pond is less than 1 m, gradually increasing from the pond edge to the central deep pond. The density of planted withered grass in the deep - water area is 25 plants / m²; the density of planted iris in the shallow - water area is 8 - 12 plants / m². Aquatic organisms at different trophic levels are used to further utilize the inorganic substances decomposed by the water body, enhancing the self - purification ability of the water body and restoring the vitality of the water body.

[0041] The first filter dam is set between the sedimentation tank and the aeration tank, and the second filter dam is set between the aeration tank and the ecological purification pond. The first filter dam and the second filter dam are of a steel - cage packing structure. Fillers of different sizes are filled in the dam body. The fillers can be selected from ceramsite, volcanic stone, gravel, cobblestone, small stones, palm pieces, ceramic beads and other filler media, and the filler gradation is designed. In one embodiment, the filter dam is filled with a graded filler of ceramsite, volcanic stone and palm pieces, the filler particle size is 5 - 50 mm, and the filling layer thickness is 1.2 - 1.8 m. Through the synergistic action of physical interception and biofilm adsorption, the TP removal rate ≥ 50%.

[0042] In one or more embodiments of this specification, an ecological treatment system for removing antibiotics from aquaculture tail water includes: an ecological ditch section with a plant interception zone at the front end and connected to an antibiotic removal module at the end; the antibiotic removal module consists of a metal - loaded module, suspended fillers and an ecological floating island, wherein the metal - loaded module is detachable and replaceable; a multi - stage purification unit, including a sedimentation tank, a first filter dam, an aeration tank, a second filter dam, and an ecological purification pond, and each unit is connected by self - flow under a hydraulic gradient.

[0043] A diversion retaining wall is provided between the metal - loaded module 1 and the ecological floating island 5, and the retaining wall 2 enhances the contact efficiency of pollutants with the metal - loaded module, the ecological floating island and the suspended fillers through hydraulic turbulence.

[0044] Taking a case in Shandong Province as an example, experiments were carried out using the process of the present invention. The aquaculture area covers an area of 3,099 mu, with a water area of 1,926 mu, a tail water discharge of 39,663 m³ / d, and the peak drainage period is concentrated in November - December. The project adopts the following process: ecological ditch - sedimentation tank - first filter dam - aeration tank - second filter dam - ecological purification tank. The sedimentation tank has a water depth of 1.5 m and an area of 81 mu. Artificial waterweeds are designed at the inlet and outlet of the sedimentation tank. The area of the artificial waterweeds is 495 ㎡ and the length is 1.5 m. The aeration tank has a water depth of 2.0 m and an area of 16.5 mu. The aeration heads are installed more than 30 cm above the bottom of the tank. The ecological purification tank has a water depth of 2.5 m and an area of 81 mu. Emergent plants such as Iris pseudacorus and Nelumbo nucifera are planted in the shallow water area near the shore, and submerged plants such as Vallisneria natans and Myriophyllum verticillatum are planted in the deep water area. The total length of the ecological ditch is 300 m. The length of the traditional ecological ditch at the front end is 240 m and the water depth is 1.5 m. Aquatic plants such as Iris pseudacorus, Nelumbo nucifera, and Myriophyllum verticillatum are planted in an area of 488 ㎡. The water depth of the antibiotic removal module at the rear end is 1.5 m, with a total length of 60 m and the length of the metal-loaded module is 40 m. Vetiveria zizanioides is planted in an area of 100 ㎡, the area of the ecological floating bed is 100 ㎡, the diameter of the suspended packing is 150 mm, and the number is 2,400.

[0045] After the project has been operating stably for 3 years, the removal rates of nutrients CODMn, NH3-N, TP, and TN by the system are 35%, 68%, 63%, and 60% respectively, and the removal rates of sulfamethoxazole and trimethoprim detected in the water sample reach 32% and 44% respectively; According to the data, after operating for 5 months, it can stably meet the requirements of SC / T 9101—2007 "Discharge Requirements for Freshwater Pond Aquaculture Water".

[0046] An ecological treatment process and system for removing antibiotics from aquaculture tail water provided by one or more embodiments of this specification achieve the efficient removal of antibiotics in aquaculture tail water through the synergistic effects of physical adsorption and plant absorption, improve the water ecology, and mainly use physical and biological means for treatment, reducing secondary pollution. It has a long service life and can operate continuously for 3 - 5 years to ensure the sustainability of the treatment effect. The modular component design supports rapid replacement and upgrade, significantly reducing the maintenance cost and time. It has low energy consumption, low initial investment, and low operating cost.

[0047] The above describes specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve the desired results. Additionally, the processes depicted in the drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0048] The above description is only for one or more embodiments of this specification and is not intended to limit this specification. For those skilled in the art, various changes and modifications can be made to one or more embodiments of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of one or more embodiments of this specification shall be included within the scope of the claims of this specification.

Claims

1. An ecological treatment process for removing antibiotics from aquaculture tail water, characterized in that, Including: Sedimentation and interception treatment of the tail water is carried out at the front end of the ecological ditch; The antibiotics in the tail water are removed by the antibiotic removal module arranged at the end of the ecological ditch, wherein the antibiotic removal module includes a metal-loaded module, suspended packing and an ecological floating island; The tail water passing through the antibiotic removal module is subjected to multi-stage purification by a sedimentation tank, a first filter dam, an aeration tank, a second filter dam and an ecological purification tank.

2. The ecological treatment process for removing antibiotics from aquaculture tail water according to claim 1, characterized in that, The metal-loaded module is BiVO4 loaded on activated carbon fiber, and the pollution load is 0.2 - 0.4 g / (m²·d).

3. An ecological treatment process for removing antibiotics from aquaculture tail water according to claim 1, characterized in that, The ecological floating island is made by fixing multiple floating bodies made of HDPE through connecting fasteners. Injection-molded hollow planting baskets are arranged on the surfaces of the floating bodies. Volcanic rock matrix is filled in the planting baskets, and the roots of vetiver grass penetrate through the planting baskets and contact the suspended packing to form a biofilm-plant synergistic degradation interface.

4. An ecological treatment process for removing antibiotics from aquaculture tail water according to claim 1, characterized in that, The suspended packing is made of volcanic rock or activated carbon, fixed by nylon ropes, with the same horizontal spacing as the spacing of the ecological floating islands, and fixed 0.5 m vertically below the ecological floating islands to form a three-dimensional biofilm attachment space.

5. An ecological treatment process for removing antibiotics from aquaculture tail water according to claim 1, characterized in that, The sedimentation tank has a depth of 2.5 - 3.5 m and artificial aquatic plants are hung, and the length of the artificial aquatic plants is 1.5 m.

6. The ecological treatment process for removing antibiotics from aquaculture tail water according to claim 1, characterized in that, An aerator is installed at 30 - 50 cm from the bottom of the aeration tank, and the depth of the aeration tank is 2.5 m.

7. An ecological treatment process for removing antibiotics from aquaculture tail water according to claim 1, characterized in that, The water depth in the deep water area of the ecological purification tank is 3.0 - 4.0 m, and the water depth in the shallow water area is < 1 m. Emergent plants and submerged plants are planted.

8. An ecological treatment process for removing antibiotics from aquaculture tail water according to claim 1, characterized in that, The first filter dam is arranged between the sedimentation tank and the aeration tank, and the second filter dam is arranged between the aeration tank and the ecological purification tank. The first filter dam and the second filter dam are steel cage packing structures.

9. An ecological treatment system for removing antibiotics from aquaculture tail water, characterized in that, Including: An ecological ditch section, with a plant interception belt at the front end and connected to the antibiotic removal module at the end; The antibiotic removal module is composed of a metal-loaded module, suspended packing and an ecological floating island, wherein the metal-loaded module is detachable and replaceable; A multi-stage purification unit, including a sedimentation tank, a first filter dam, an aeration tank, a second filter dam and an ecological purification tank, and each unit is connected by self-flow under the hydraulic gradient.

10. An ecological treatment system for removing antibiotics from aquaculture tail water according to claim 9, characterized in that, A diversion retaining wall is arranged between the metal-loaded module and the ecological floating island, and the retaining wall enhances the contact efficiency of pollutants with the metal-loaded module, the ecological floating island and the suspended packing through hydraulic turbulence.

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