An ecological purification method for treating aquaculture tail water

Abstract

The present application provides a kind of ecological purification method for treating aquaculture tail water, and is sequentially provided with multifunctional drainage ditch, ecological oxidation dam, stable sedimentation pond, continuous biological filter pond and composite purification bed along the direction of aquaculture tail water flow.The garbage intercepting device, ecological revetment and buffer zone are arranged in the multifunctional drainage ditch;The ecological weir, ecological frame, fixed pile, water collecting wall and lifting pump are arranged in the ecological purification dam;The floating plant area, multiple interception and purification devices and aeration device are arranged in the stable sedimentation pond;The culture area is arranged in the continuous biological filter pond, and after the water flow passes through multiple aeration biological filter areas, it enters the effluent area uniformly;The composite purification bed includes plants, improved substrate layer, purification layer, filtration and water collection layer, impermeable layer and effluent area.The method can effectively remove the refractory pollutants and toxic and harmful substances in aquaculture tail water, has low construction cost, small land area, low operation and maintenance cost, and the effluent can be resource utilization.

Description

Technical Field

[0001] This invention relates to the fields of agricultural non-point source pollution control and water environment management, and in particular to an ecological purification method for treating aquaculture wastewater. Background Technology

[0002] With economic development and improved living standards, aquaculture has rapidly developed to meet the growing demand for high-quality protein, adopting intensive and high-density farming models. In 2021, my country's aquaculture output reached 53.94 million tons, with pond aquaculture accounting for 60% of inland aquaculture output. During the farming process, excessive fertilization and feeding are common, resulting in large amounts of fertilizer, uneaten feed, and fish excrement remaining in the water, leading to a continuous deterioration of the aquaculture environment and increasing the risk of various fish diseases. Surveys show that the pollution intensity of COD, NH3-N, TN, and TP from aquaculture is 13.6 kg / t, ammonia nitrogen is 0.45 kg / t, total nitrogen is 2.02 kg / t, and total phosphorus is 0.33 kg / t, accounting for 6.24%, 10.31%, 7.00%, and 7.59% of total agricultural emissions, respectively. In addition, most of the fish drugs and environmental conditioners widely used in aquaculture are discharged directly into the surrounding water environment in their raw form along with pollutants, which poses a great threat to the aquatic ecosystem and human health.

[0003] Aquaculture wastewater purification methods can be categorized into in-situ purification and ex-situ purification based on the treatment location. In-situ purification includes methods such as reducing stocking density, adsorption and filtration, flocculation and oxidation, and the use of aquatic plants and microorganisms. Ex-situ purification typically employs methods such as recirculating aquaculture systems, constructed wetlands, stabilization pond purification systems, and "three ponds and two dams" systems. In-situ purification has limited water purification capacity within the aquaculture area, easily impacting aquatic product yields, and is subject to numerous limiting factors, resulting in a narrow application range. Ex-situ purification typically requires a large land area, has a low pollutant removal load, is highly susceptible to environmental temperature fluctuations, is prone to clogging, and has a short system lifespan. It also lacks removal processes specifically targeting toxic and harmful substances such as antibiotics and heavy metals in aquaculture wastewater, leading to incomplete purification. Furthermore, regardless of whether it's in-situ or ex-situ purification, the resulting sludge or pond mud is often disposed of as solid waste, hindering resource recycling. Summary of the Invention

[0004] To address the above problems, this invention proposes an ecological purification method for treating aquaculture wastewater. Through reasonable layout, it occupies a small area, has strong resistance to load shocks, high pollutant removal capacity, and long service life. It can effectively purify conventional inorganic pollutants in water, degrade antibiotics in water, remove heavy metals from water, and effectively utilize the bottom sediment generated in the system to reduce the amount of secondary pollutants generated.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: an ecological purification method for treating aquaculture wastewater, wherein a multifunctional drainage channel, an ecological purification dam, a stabilizing sedimentation pond, a continuous biological filter pond, and a composite purification bed are arranged sequentially along the flow direction of the aquaculture wastewater; the stabilizing sedimentation pond, the continuous biological filter pond, and the composite purification bed are selected from ponds with higher elevations, or the treated pond mud is used to fill the bottom of the pond.

[0006] in:

[0007] The multi-functional drainage channel is equipped with a garbage interception device to intercept garbage, and a buffer zone to reduce the water flow velocity and promote the sedimentation of large particles of mud and sand.

[0008] The ecological purification dam is a multi-level stepped structure that is high in the middle and low on both sides. It consists of an ecological weir and an ecological frame. The prefabricated ecological frame is equipped with an advanced oxidation box to pre-treat the aquaculture wastewater, oxidize and decompose large molecular organic matter, and degrade toxic and harmful pollutants.

[0009] The stabilizing sedimentation pond includes a water distribution channel and a partition. The water distribution channel is located at the entrance of the stabilizing sedimentation pond. The partition divides the stabilizing sedimentation pond into multiple sedimentation zones. Adjacent sedimentation zones are connected by the top or bottom of the middle partition. The water flows alternately up and down. An interception and purification device is installed every other sedimentation zone.

[0010] The continuous biological filter pond includes enclosure, cultivation zone, aerated biological filtration zone, water distribution zone and outlet. The cultivation zone is equipped with an in-situ bacterial culture box. Multiple aerated biological filtration zones are set at the output end of the cultivation zone. Water distribution zones are set between the aerated biological filtration zones. There is a microporous aeration system inside, which is set at the bottom of the continuous biological filter pond.

[0011] The composite purification bed consists of, from top to bottom, plants, improved substrate layer, purification layer, filter and water collection layer, seepage prevention layer, and water outlet area.

[0012] Preferably, the buffer zone includes a mud and sand collection hopper and a buffer device at the bottom. The buffer device is a high-strength plastic steel composite sheet pile baffle, with the top of the baffle below the water surface. An HDPE membrane is laid at the bottom of the buffer zone, and the HDPE membrane and mud and sand collection hopper in the buffer zone are fixed and maintained by pine piles.

[0013] The multi-functional drainage ditch also includes ecological revetment, which includes pine piles, base and emergent plants. The base is made of pond mud or silt excavated from the buffer zone.

[0014] Preferably, the multifunctional ecological dam includes an ecological weir, an ecological frame, fixed piles, a water collection wall, and a booster pump; the ecological weir uses double rows of pine piles, with geotextile, pebbles, gravel, and dried silt in the middle, and the water outlet is toothed; the main structure of the oxidation frame adopts a 3-layer prefabricated stepped filter frame with a height of 1500mm, and the interior uses perforated plates for layering.

[0015] Preferably, the ecological frame includes a frame body, an advanced oxidation tank, microporous aeration pipes, a substrate layer, and biomimetic aquatic plants. The substrate layer uses silt generated during the construction of this system, which is dried before use. Pebbles are laid on top of the substrate layer, and biomimetic aquatic plants are placed on top. The biomimetic aquatic plants are made of EVA ecological aquatic plants, which are soaked in a bacterial solution before use to promote the attachment of river microorganisms and the formation of a biofilm. The advanced oxidation tank is located in the upper two layers of the frame body, and the microporous aeration pipes are located at the bottom of the advanced oxidation tank. The filter media inside the advanced oxidation tank is modified iron-carbon packing, which can effectively degrade recalcitrant pollutants in the water. The advanced oxidation tank is a modular device with hooks at the top and support frames at the bottom for easy replacement of the packing. The microporous aeration pipes are laid at the bottom of the advanced oxidation tank for uniform intermittent aeration.

[0016] Preferably, the stabilizing sedimentation pond also includes a floating leaf plant area and a cleaning device. The interception and purification device includes a carrier frame and a composite fiber packing. The carrier frame is welded from 10×10mm stainless steel square steel. The floating plant area is equipped with a support net on which plants are laid. The cleaning device is an intermittent aeration device with perforated aeration pipes, fixed at the bottom of the carrier frame, 200mm away from the bottom layer of composite fiber packing.

[0017] Preferably, there are four sedimentation zones, which are four-stage static sedimentation zones. The water flows through the zones in sequence: upward flow sedimentation, downward flow sedimentation, upward flow sedimentation, and downward flow sedimentation. The alternating upward and downward water flow helps to settle suspended solids.

[0018] Preferably, the continuous biological filter pond, through the function of the water distribution zone, allows sewage to flow through multiple continuous aerated biological filtration zones in a bottom-in, top-out state, which is conducive to the full degradation and removal of pollutants in the water through the biological oxidation of the biological filter.

[0019] Preferably, multiple biological filters are set up in the aerated biological filtration zone, with pumice placed in the biological filters and a three-dimensional distributor installed at the bottom; the pumice has a large specific surface area, which can quickly attach the biofilm and is not easy to fall off; the three-dimensional distributor is mainly composed of three-dimensional mesh packing, the main body of which is a spatial three-dimensional columnar structure formed by multiple curved, intertwined and bonded filaments, with a whole mesh mat at the bottom and a triangular stack at the top.

[0020] Preferably, the modified substrate in the composite purification bed mainly uses expanded clay and superabsorbent resin. The superabsorbent resin effectively traps nutrients in the effluent, providing nutrition for plant growth. Simultaneously, its interaction with the expanded clay improves the stability of the plant root system. The purification layer is filled with zeolite, which has excellent adsorption and purification properties, effectively removing pollutants from the water. The filter and water collection layer includes a precast reinforced concrete perforated top slab, a gravel frame, and several water guide pipes. Air guide pipes are installed inside the water guide pipes, which are located between the gravel frames. The gravel frames serve to filter and protect the water guide pipes. The impermeable layer includes an HDPE membrane and a protective layer, which consists of a fine sand layer and a clay layer. In the effluent area, an aeration pipe is installed at the bottom, along with a solar-powered online monitoring system and a cover plate. The effluent is either directly discharged or reused in aquaculture ponds.

[0021] The beneficial effects of this invention are: 1) Through reasonable layout, it occupies a small area, has strong resistance to load shock, high treatment efficiency, low energy consumption, and high resource utilization; 2) The micro-electrolysis modified iron-carbon filler in the advanced oxidation device set in the ecological dam can degrade and remove toxic and harmful substances in the water, providing biochemical conditions for subsequent treatment, and the filler is easy to replace; 3) The "baffle + filler" adopted by the stabilizing sedimentation pond can increase the retention time of sewage, effectively remove suspended solids in the water, and at the same time form an oxygen-deficient environment, providing conditions for subsequent treatment; 4) The continuous biological filter adopts "enhanced microorganisms + aerated biological filtration", which has a large hydraulic load, low operating cost, small area, strong shock resistance, less affected by climate, water volume and water quality changes, high treatment efficiency, and is not easy to clog; when used in combination with the stabilizing sedimentation pond, it forms an A+O environment, which is conducive to denitrification of the system. 5) This method produces less sludge, and some processes can utilize bottom sediment, improving resource utilization and reducing the amount of secondary pollutants generated; 6) Highly absorbent resin and ceramsite do not produce secondary pollution, and can adsorb and store nutrients in the water, providing nutrients for plants; The water pipes in the water collection layer are made of HDPE corrugated mesh permeable pipes, which have a long service life, strong water collection capacity, fast drainage speed, and a non-porous bottom to prevent secondary leakage and strong anti-clogging ability. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only preferred embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the process flow of the present invention;

[0024] Figure 2 This is a plan view of the multifunctional ecological canal and multifunctional ecological dam of the present invention;

[0025] Figure 3 This is a cross-sectional schematic diagram of the multifunctional ecological dam of the present invention;

[0026] Figure 4 This is a schematic cross-sectional view of the purification box of the present invention;

[0027] Figure 5 This is a schematic diagram of the stable sedimentation pond of the present invention;

[0028] Figure 6 This is a schematic cross-sectional view of the stable sedimentation pond of the present invention;

[0029] Figure 7 This is a schematic diagram of the continuous biological filter pond of the present invention;

[0030] Figure 8 This is a schematic cross-sectional view of the continuous biological filter pond of the present invention;

[0031] Figure 9 This is a three-dimensional schematic diagram of the biological filter of the present invention;

[0032] Figure 10 This is a schematic diagram of the installation of the three-dimensional distributor of the present invention;

[0033] Figure 11 This is a schematic diagram of the composite purification bed of the present invention;

[0034] Figure 12 This is a schematic cross-sectional view of the composite purification bed of the present invention. Detailed Implementation

[0035] To better understand the technical content of this invention, specific embodiments are provided below, and the invention will be further described in conjunction with the accompanying drawings.

[0036] The embodiments of the present invention address the problems of effectively removing pollutants from aquaculture wastewater in the prior art, as well as the shortcomings of the prior art such as low pollution load resistance, large footprint, and weak impact resistance. They provide an ecological purification method for treating aquaculture wastewater, which can remove refractory organic pollutants from aquaculture wastewater, has strong adaptability to the treatment system, strong pollution load resistance, small footprint, and produces less sludge.

[0037] Figure 1 This is a schematic diagram of the process flow for treating aquaculture wastewater according to the present invention, including a multi-functional drainage ditch 1, an ecological purification dam 2, a stabilizing sedimentation pond 3, a continuous biological filter pond 4, and a composite purification bed 5.

[0038] Figure 2 This is a plan view of the multifunctional ecological canal 1 and multifunctional ecological dam 2 of the present invention. The multifunctional drainage canal 1 includes a garbage interception device 11, an ecological revetment 12, and a buffer zone 13;

[0039] The aforementioned garbage interception device 11 includes a garbage interception net 111, a garbage collector 112, and a garbage interception enclosure 113. The garbage interception net 111 uses ordinary plastic netting to initially intercept large pieces of floating garbage on the water surface. The garbage collector 112 is installed on both sides of the river or ditch to collect the garbage blocked by the garbage interception enclosure 11, effectively removing garbage from the water surface. The garbage interception enclosure 113 is approximately 1m to 2m high, and its height is determined according to the water depth.

[0040] The ecological revetment 12 is installed on both sides of the upstream of the multi-functional drainage channel 1, and consists of pine piles 121, a base 122, and emergent plants 123. It not only prevents water erosion of the bank but also promotes the ecological balance among the water, sediment, plants, and microorganisms. The base is made from silt excavated from the buffer zone 13, which, after treatment, is filled into the ecological revetment 12. The emergent plants used are perennial emergent plants such as pickerelweed and sedge.

[0041] The buffer zone 13 includes a 4m long bottom hopper buffer zone, a sediment collection hopper 131, and a buffer device 132. The buffer device 132 is a high-strength plastic-steel composite sheet pile baffle, with the top of the baffle 50cm below the water surface. An HDPE membrane is laid at the bottom of the buffer zone 13, and the HDPE membrane and sediment collection hopper 131 within the buffer zone are fixed and maintained by pine piles. The buffer device 132 reduces the water flow velocity, increases the hydraulic residence time of the water, and promotes the deposition of large particles of sediment to the bottom. The sediment collection hopper 131 is periodically cleaned using a small vacuum truck. The buffer device 132 uses high-strength plastic-steel composite sheet piles, which are easy to construct, have low maintenance costs, save on project costs, improve construction efficiency, and have a long service life, are robust and durable, and are suitable for aquatic environments.

[0042] Figure 2 , Figure 3 The plan and cross-sectional views of the multifunctional ecological dam 2 of the present invention are shown. The multifunctional ecological dam 2 includes an ecological weir 21, an ecological frame 22, fixed piles 23, a water collection wall 24, and a lift pump 25. The ecological weir 21 of the ecological purification dam 2 adopts double-row pine piles 211, with geotextile 212, pebbles 213, crushed stone 214, and dried silt 215 in the middle, and the water outlet is toothed. The ecological frame 22 is divided into three layers.

[0043] The ecological frame 22 includes a frame body 221, an advanced oxidation box 222, microporous aeration pipes 223, a substrate layer 224, and biomimetic aquatic plants 225. The frame body 221 employs a three-layer prefabricated stepped filter frame structure, using perforated plates for layering. The substrate layer 224 uses sludge generated during the system's construction process, which is dried before use. An 8-10cm layer of pebbles is laid on top of the substrate layer 224. The advanced oxidation box 222 and microporous aeration pipes 223 are placed on the upper and lower layers of the frame body 221. The advanced oxidation box 222 is a modular device, measuring 40cm × 30cm × 20cm, using a corrosion-resistant mesh box. The filler is easy to replace and not easily clogged. The filter media inside the advanced oxidation box 222 is modified iron-carbon filler 222(b), with a thickness of approximately 8-10cm, ensuring sufficient aeration and preventing caking. Figure 4 This is a schematic diagram of the advanced oxidation tank 222. The tank has hooks 222(a) on the top and a support frame 222(c) at the bottom for easy replacement without affecting aeration. The modified iron-carbon filler 222(b) can be used for low-concentration neutral water. Utilizing the potential difference between iron and carbon, the modified iron-carbon filler 222(b) forms numerous micro-galvanic cells in the water. Through the action of a micro-electric field, pollutants undergo oxidation-reduction reactions, causing ring-opening and chain breaking of large organic molecules, reducing the toxicity of toxic substances in the effluent. The COD removal rate can reach approximately 30%, while simultaneously improving the biodegradability of subsequent treatments.

[0044] The microporous aeration pipes 223 are laid at the bottom of the advanced oxidation tank 222 for uniform intermittent aeration. The ultrafine bubbles generated by the microporous aeration pipes 223 have a large gas-liquid contact area, low upward flow velocity, and good dissolved oxygen mass transfer efficiency, which is conducive to the formation of micro-galvanic cells in the iron-carbon filler and promotes the degradation of water pollutants. The biomimetic aquatic plants 225 are placed on the surface of the substrate layer 224. The biomimetic aquatic plants 225 are commonly used EVA ecological aquatic plants. Before use, they are soaked in bacterial solution, which helps to promote the attachment of river microorganisms and quickly form a biofilm.

[0045] Figure 5 , Figure 6This is a plan and cross-sectional schematic diagram of the stabilizing sedimentation pond 3 of the present invention. The stabilizing sedimentation pond 3 includes a water distribution channel 31, a enclosure 32, an interception and purification device 33, a floating-leaved plant area 34, and a cleaning device 35. The water distribution channel 31 mainly uses DN300 half-pipes, which can be made of PVC or precast concrete. The enclosure 32 uses ecological enclosures to divide the pond. There are three sets of enclosures. The first and third sets of enclosures use top water passage and bottom water blocking with ecological bags filled with original soil. The second set of enclosures... The bottom water flow is adopted to form a baffle; the interception and purification device 33 includes a carrier frame 331 and a combined fiber filler 332. The carrier frame 331 is welded from 10×10mm stainless steel square steel; the floating plant area 34 is equipped with a support net 341, on which plants 342, such as pollution-resistant emergent plants or floating-leaved plants like Myriophyllum spicatum, are arranged; the cleaning device 35 is an intermittent aeration device, which uses perforated aeration pipes and is fixed to the bottom of the carrier frame 331, 200mm away from the bottom layer of combined fiber filler.

[0046] The stable sedimentation pond 3 has a floating plant area 34, where the floating plants 342 are one or more of pennywort, green foxtail, and water hyacinth. The floating plants are harvested and cleaned periodically according to their growth. The floating plants cover the water surface, creating a certain hypoxic or anaerobic environment, which hydrolyzes and acidifies some large organic molecules in the effluent that are difficult to degrade into small organic molecules that are easy to biodegrade, thereby further improving the biodegradability of the effluent.

[0047] Reference Figure 5 , Figure 6 As shown, the enclosure 32 of the stabilizing sedimentation pond 3 includes several isolation barriers set along the short side of the sedimentation pond, dividing the space inside the sedimentation pond into several sedimentation zones. Adjacent sedimentation zones are connected through the top or bottom of the isolation barriers, and the water flows in an alternating up-down direction. The aquaculture wastewater passes through the combined fiber filler 332 and the floating plant area 34 respectively. Through the separation effect of the enclosure 32, four-stage static sedimentation is set up, which successively passes through upward flow sedimentation, downward flow sedimentation, upward flow sedimentation, and downward flow sedimentation. The alternating up-down water flow direction helps the sedimentation of suspended solids.

[0048] Reference Figure 7 The continuous biological filter pond 4 includes an enclosure 41, a cultivation zone 42, an aerated biofilm zone 43, a water distribution zone 44, and an outlet 45. Aquaculture wastewater is evenly distributed in the cultivation zone 42 and then uniformly enters the aerated biological filter zone 43, where it undergoes biological oxidation and is immobilized by the interception of suspended matter. An in-situ bacterial culture tank 421 is installed within the cultivation zone. The in-situ bacterial culture tank 421 mainly consists of sludge particles, a culture tank body, a solar pump, a controller, a nutrient solution delivery pipe, and a bacterial solution delivery pipe. (Refer to...) Figure 8 and Figure 9The aerated biological filtration zone 43 is divided into several biological filters 431 and a water distribution zone 432 by a partition 41. Through the water distribution zone 432, wastewater flows through the biological filters 431 in a bottom-in, top-out manner, which facilitates the full degradation and removal of pollutants in the water within the biological filters 431. An aeration system 433 is installed within the aerated biological filtration zone 43. The biological filters 431 are made of stainless steel and consist of a stainless steel support 431(a) and a stainless steel screen 431(b). The stainless steel screen 431(b) prevents filter media loss. Lightweight ceramic granules 434 are placed in the middle of the biological filter 431, and a three-dimensional distributor 435 is installed at the bottom.

[0049] Reference Figure 10 The biological filter 431 in the aerated biological filtration zone 43 contains pumice with a particle size of 2-4 cm and a density of 650-800 kg / m³. 3 It can be evenly distributed in the upper part of the water body, has a large specific surface area, can quickly form a surface biofilm, and is not easy to fall off or clog. The three-dimensional distributor 435 is mainly composed of three-dimensional mesh packing. The main body of the packing is a spatial three-dimensional columnar structure formed by multiple curved, intertwined, and mutually bonded filaments. The lower part is a whole mesh mat, and the upper part is stacked in a triangle. During the operation of the system, the gas is driven by the three-dimensional flow of sewage, colliding with each other and being continuously cut into smaller bubbles by the spiral mesh, which increases the oxygen utilization rate and can reduce the aeration volume. The enclosure 41 is closely attached to the biological filter 431 to form a certain closed space.

[0050] The in-situ bacterial culture chamber 421 within the cultivation zone 42 of the continuous biological filter pond 4 measures 1m × 1m × 1.2m. It uses stainless steel as a support, and 800-mesh filter cloth is fixed to the support to form a chamber. The top can be opened for easy addition of nutrients and bacterial strains. A control box and solar pump are installed nearby, and the bacterial solution is periodically transported to the aerated biological filtration zone, which helps maintain system stability and provides a certain degree of resistance to load shocks.

[0051] The continuous biological filter pond 4 adopts the principle of "enhanced microorganisms + aerated biological filtration", which has a large hydraulic load and improves biological oxidation capacity. When used in combination with the stable sedimentation pond 3, it forms an "A+O" environment, which is conducive to the system to further remove pollutants and denitrify.

[0052] Reference Figure 11 , Figure 12The composite ecological purification bed 5 comprises, from top to bottom, plants 51, a modified substrate layer 52, a purification layer 53, a filter and water collection layer 54, an impermeable layer 55, and a water outlet zone 56. Plants 51 include a water distribution ditch 511 and wetland plants 512. The water distribution ditch 511 uses a DN400 half-pipe, which can be made of PVC or precast concrete, and is equipped with a toothed water outlet weir. The wetland plant 512 consists of ornamental plants such as canna lilies, irises, and calamus, or economic and cold-resistant plants such as milkvetch and alfalfa; the improved substrate layer 52 is mainly filled with 100cm thick ceramsite and superabsorbent polymer resin in a mass ratio of 100:5. To prevent resin loss, a partition layer is added at the bottom; the superabsorbent resin is 10-15 mesh, and the partition layer is 10 mesh nylon filter cloth; the purification layer 53 is filled with zeolite; the filter water collection layer 54 includes a perforated top plate 541, a gravel frame 542, and several water pipes 543. The perforated top plate 541 is a precast reinforced concrete slab that provides support and is placed on top of the gravel frame. An air-guiding pipe is installed inside the water-guiding pipe, which is located between the gravel frames. The gravel frames serve to filter and protect the water-guiding pipe. The impermeable layer includes an HDPE membrane and a protective layer, which consists of a fine sand layer and a clay layer. In the water outlet area 56, an aeration pipe is installed at the bottom, and a solar online monitoring system and a cover are also provided. The effluent is directly discharged or reused in aquaculture ponds.

[0053] The superabsorbent resin in the modified matrix layer 52 of the composite purification bed 5 is a high molecular weight organic material that does not produce secondary pollution. It has a particle size of 10-15 mesh and expands to a transparent resin with a particle size of 10mm-20mm after absorbing water. The superabsorbent resin can effectively absorb nutrients in the water and has a slow-release effect, which can continuously provide nutrients for plant growth and remove pollutants. At the same time, it interacts with the ceramsite, which is beneficial to improving the stability of the plant root system.

[0054] The water pipe in the water collection layer 54 is made of HDPE corrugated mesh permeable pipe, which has strong anti-clogging ability, long service life, strong water collection capacity, fast drainage speed, and the bottom is a non-porous part to prevent secondary leakage.

Claims

1. An ecological purification method for treating aquaculture wastewater, characterized in that: Along the flow direction of aquaculture wastewater, a multi-functional drainage channel, an ecological purification dam, a stabilizing sedimentation pond, a continuous biological filter pond, and a composite purification bed are sequentially arranged. Specifically: The multi-functional drainage channel is equipped with a garbage interception device to intercept garbage and a buffer zone to reduce water flow velocity and promote the sedimentation of large particles of silt; The ecological purification dam is a multi-tiered structure with a higher center and lower sides, consisting of an ecological weir and an ecological frame. An advanced oxidation box is installed inside the prefabricated ecological frame, with modified iron-carbon filler as the filter media to pre-treat the aquaculture wastewater, oxidizing and decomposing large molecular organic matter and degrading toxic and harmful pollutants; The stabilizing sedimentation pond includes a water distribution channel and an enclosure. The water distribution channel is located at the entrance of the stabilizing sedimentation pond, and the enclosure divides the pond into multiple sedimentation zones. Adjacent sedimentation zones are connected by the top or bottom of the central enclosure, with water flowing alternately up and down. A filtration and purification device is installed every other sedimentation zone. Furthermore, the stabilizing sedimentation pond is covered with floating-leaved plants to create an oxygen-deficient environment; The continuous biological filter pond includes enclosures, a cultivation zone, an aerated biological filtration zone, a water distribution zone, and an outlet. The cultivation zone contains an in-situ bacterial culture chamber, and multiple aerated biological filtration zones are located at the output end of the cultivation zone. A water distribution zone connects the aerated biological filtration zones, and a microporous aeration system is located at the bottom of the continuous biological filter pond. The composite purification bed, from top to bottom, consists of plants, a modified substrate layer, a purification layer, a filter water collection layer, a seepage-proof layer, and an outlet zone. The modified substrate layer is mainly composed of ceramsite and superabsorbent polymer resin. Aquaculture wastewater first passes through a multi-functional drainage channel for waste interception and to reduce water flow velocity before entering an ecological purification dam. In the ecological purification dam, macromolecular organic matter is oxidized and decomposed, and toxic and harmful pollutants are degraded. Then, it enters a stabilization sedimentation pond for sedimentation and decomposition, followed by microbial oxidation treatment in the continuous biological filter pond, and finally filtration and purification in the composite purification bed. The effluent is either reused or discharged into natural water bodies.

2. The ecological purification method for treating aquaculture wastewater according to claim 1, characterized in that: The buffer zone includes a sediment collection hopper and a buffer device at the bottom. The buffer device is a high-strength plastic-steel composite sheet pile baffle, with the top of the baffle below the water surface. An HDPE membrane is laid at the bottom of the buffer zone, and the HDPE membrane and sediment collection hopper in the buffer zone are fixed and maintained by pine piles. The multi-functional drainage channel also includes an ecological revetment, which includes pine piles, a base, and emergent plants. The base is made of pond mud or silt excavated from the buffer zone.

3. The ecological purification method for treating aquaculture wastewater according to claim 2, characterized in that: The multifunctional ecological dam includes an ecological weir, an ecological frame, fixed piles, a water collection wall, and a lift pump. The ecological weir uses double rows of pine piles with geotextile, pebbles, gravel, and dried silt in the middle, resulting in a toothed water outlet. The main structure of the ecological frame uses a three-layer prefabricated stepped filter frame located on both sides of the ecological weir. The interior uses perforated plates in layers, with advanced oxidation boxes installed in the upper two layers. Microporous aeration pipes are laid at the bottom of the advanced oxidation device for uniform intermittent aeration.

4. The ecological purification method for treating aquaculture wastewater according to claim 3, characterized in that: The ecological frame includes a frame, an advanced oxidation box, microporous aeration pipes, a substrate layer, and biomimetic aquatic plants. The substrate layer is made of silt generated during the construction of this system, which is dried before use. The top of the substrate layer is covered with pebbles and placed with biomimetic aquatic plants. The biomimetic aquatic plants use EVA ecological aquatic plants, which are soaked in bacterial solution before use to promote the attachment of river microorganisms and generate a surface biofilm; the advanced oxidation tank is a modular device.

5. The ecological purification method for treating aquaculture wastewater according to claim 1, characterized in that: The stabilizing sedimentation pond also includes a floating leaf plant area and a cleaning device. The interception and purification device includes a carrier frame and a composite fiber packing. The carrier frame is welded from 10×10mm stainless steel square steel. The floating plant area is equipped with a support net on which plants are laid. The cleaning device is an intermittent aeration device with perforated aeration pipes, fixed to the bottom of the carrier frame, 200mm away from the bottom layer of composite fiber packing.

6. The ecological purification method for treating aquaculture wastewater according to claim 5, characterized in that: The stabilizing sedimentation pond has four sedimentation zones, which are four-stage static sedimentation. The water flows through upward and downward flow sedimentation in sequence, and the alternating upward and downward flow of the water helps to settle suspended solids.

7. The ecological purification method for treating aquaculture wastewater according to claim 6, characterized in that: The continuous biological filter pond, through the water distribution zone, allows sewage to flow through multiple continuous aerated biological filtration zones in a bottom-in, top-out manner, which is conducive to the full degradation and removal of pollutants in the water through the biological oxidation of the biological filter.

8. The ecological purification method for treating aquaculture wastewater according to claim 7, characterized in that: Multiple biological filters are installed in the aerated biological filtration zone. Pumice stones are placed in the biological filters, and a three-dimensional distributor is installed at the bottom. The three-dimensional distributor is mainly composed of three-dimensional mesh packing. The main body of the packing is a spatial three-dimensional columnar structure formed by multiple curved, intertwined, and mutually bonded filaments. The lower part is a whole piece of mesh mat, and the upper part is stacked in a triangular shape.

9. The ecological purification method for treating aquaculture wastewater according to claim 1, characterized in that: The improved matrix layer inside the composite purification bed also includes a partition layer. The superabsorbent resin is 10-15 mesh, and the partition layer is 10 mesh nylon filter cloth. The purification layer is filled with zeolite. The filter and water collection layer includes a perforated top plate, a gravel frame, and several water guide pipes. Air guide pipes are installed inside the water guide pipes. The water guide pipes are located between the gravel frames. The gravel frames serve to filter and protect the water guide pipes. The impermeable layer includes an HDPE membrane and a protective layer. The protective layer consists of a fine sand layer and a clay layer. In the effluent area, an aeration pipe is installed at the bottom, and a solar online monitoring system and a cover are installed. The effluent is directly discharged or reused in aquaculture ponds.

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