A self-cleaning filler for constructed wetlands and its preparation method

Abstract

This invention discloses a novel self-cleaning filler for constructed wetlands and its preparation method, comprising: a skeleton layer including ceramsite and a filler, wherein the ceramsite and the filler are integrally formed, the ceramsite being composed of multiple ceramsite particles, and the filler being a mixture of microbial strains and starch; a first coating layer surrounding the skeleton layer; and a second coating layer. This invention utilizes diatomaceous earth-type ceramsite as the skeleton, fully leveraging the compressive strength and porosity of the ceramsite. Fluorescent Pseudomonas aeruginosa and starch are injected into the ceramsite using a vacuum pressurization method, and a binder is added during the granulation process. The raw materials used in the original filler are supplemented with impregnated corn fiber. Under normal temperature conditions, the impregnated corn fiber degrades first and then gradually dissolves to form channels, improving the peristaltic microenvironment of plants growing in the wetland. The water flow velocity in the wetland is reduced to a minimum, without affecting the wetland's water treatment efficiency.

Description

Technical Field

[0001] This invention relates to the field of constructed wetland technology, and in particular to a self-cleaning filler for constructed wetlands and its preparation method. Background Technology

[0002] Constructed wetlands are artificially built and controlled wetlands similar to marshes. Wastewater and sludge are systematically distributed onto these artificially constructed wetlands. As the wastewater and sludge flow in a certain direction, the technology mainly utilizes the physical, chemical, and biological synergistic effects of soil, artificial media, plants, and microorganisms to treat the wastewater and sludge.

[0003] In existing constructed wetlands, whether surface flow or subsurface flow, most filler materials use gravel and volcanic rock, while some use iron filings, steel slag, zeolite, charcoal, and limestone. Although constructed wetlands are typically designed for 15-20 years of operation, primarily focusing on phosphorus adsorption and removal—with phosphorus adsorption handled by the filler material itself, and removal mainly occurring as nutrients for plants like reeds, canna lilies, and irises—the filler material experiences a significant decline in its adsorption capacity after 2-3 months of operation. This decline is exacerbated by the proliferation and death of microorganisms, especially when water quality is poor. This decreases the water flow rate and reduces the water's residence time within the constructed wetland, impacting its treatment efficiency. No solutions or technologies have been implemented to address the issue of dead microorganisms adhering to the filler material surface. Summary of the Invention

[0004] This invention provides a self-cleaning filler for artificial wetlands and its preparation method. It uses diatomaceous earth-type ceramsite as a framework, fully utilizing the compressive strength and porous structure of the ceramsite. Fluorescent Pseudomonas aeruginosa and starch are injected into the ceramsite using a vacuum pressurization method. A binder is added during the granulation process. The raw materials used in the original filler are infused with corn fiber. At room temperature, the infused corn fiber degrades first and then gradually dissolves to form channels, preventing dead microorganisms from adhering to the surface of the original filler. This improves the peristaltic microenvironment of plants growing in the wetland, and reduces the water flow rate in the wetland to a minimum, without affecting the wetland's water treatment efficiency.

[0005] To address the aforementioned technical problems, this invention provides a self-cleaning filler for artificial wetlands, comprising: The skeleton layer includes ceramsite and filler, wherein the ceramsite and the filler are integrally formed, the ceramsite is composed of multiple ceramsites, and the filler is a mixture of microbial strains and starch. A first covering layer is disposed around the outside of the skeleton layer; The second covering layer is disposed around the outside of the first covering layer; Corn fiber is impregnated and mixed and disposed inside the first coating layer and the second coating layer; The channels are pre-formed in multiple ways, with one end of each channel extending into the interior of the skeleton layer and the other end extending into the exterior of the second covering layer.

[0006] As a preferred embodiment of the above technical solution, the ceramsite is set as diatomaceous earth type ceramsite, the particle size of the diatomaceous earth type ceramsite is 0.5-1.5cm, the porosity of the diatomaceous earth type ceramsite is 65-72%, and the compressive strength is 0.2-0.3Mpa.

[0007] As a preferred embodiment of the above technical solution, the microbial strain is set as *Pseudomonas fluorescens*, the starch is set as β-starch, and the microbial strain and starch mixture are mixed in a ratio of 1:25 to 1:30.

[0008] As a preferred embodiment of the above technical solution, the first coating layer is a mixture of peat moss, impregnated corn fiber, and clay, and the second coating layer is a mixture of iron powder, zeolite powder, impregnated corn fiber, and clay. The length of a single impregnated corn fiber is 0.2-0.3 mm, and the mass ratio of the impregnated corn fiber to the first coating layer and the second coating layer is 100:0.6-100:1.0, respectively.

[0009] This invention also provides a method for preparing self-cleaning filler for artificial wetlands, specifically including the following steps: Step 1: Select multiple ceramsites, and prepare a filler by selecting a mixture of microbial strains and starch in a specific ratio; Step 2: Fill the sealed chamber with diatomaceous earth-type ceramsite, turn on the vacuum pump to evacuate the chamber, and turn off the vacuum pump after the evacuation is complete. Step 3: Open the valve to add the mixture of microbial inoculum and starch into the chamber, then close the valve; Step 4: Turn on the pressure pump to pressurize the sealed chamber and mix the filler and ceramsite into one. Step 5: Granulate the ceramsite that has been injected with microbial agent and starch, and add a binder during the granulation process. After granulation, the filler is dried by hot air and gradually shaped. Step Six: Select an area of ​​appropriate size for the molded ceramsite and filler mixture according to the required wetland size. Soak corn fiber in PVA-1788 solution for 20 minutes, then remove it, air dry it, break it into flocculent state, and mix it with peat moss, clay, iron powder, and zeolite powder to form the first and second coating layers. Then, coat the outside of the first and second coating layers in sequence, and then dry it to complete the preparation of the entire artificial wetland self-cleaning filler.

[0010] As a preferred embodiment of the above technical solution, in step two, the vacuum pump operates at a vacuum level of 0.08 MPa for 5-10 minutes. In step four, the pressurizing pump pressurizes the sealed chamber to 0.2 MPa, which can be repeated multiple times, with each pressurization lasting 5-20 minutes.

[0011] As a preferred embodiment of the above technical solution, in step three, a mixture of microbial strains and starch is added, and the volume of the mixture is 60% of the volume of the sealed chamber.

[0012] As a preferred embodiment of the above technical solution, the binder in step five is set as a polyvinyl alcohol solvent, the ratio of water to PVA is 1:8:-1:10, the temperature of the aqueous solution is set to 40-50 degrees Celsius, and the ratio of PVA-1788 to PVA-1799 is 2:7:-3:8.

[0013] As a preferred embodiment of the above technical solution, the hot air drying in step five is performed using a hot air blower with an outlet air temperature of 45-55 degrees Celsius.

[0014] As a preferred embodiment of the above technical solution, after the binder forms the filler layer of the ceramsite skeleton, it will fix each layer on the outer layer of the ceramsite. Under normal temperature conditions, the corn fiber will degrade first and then gradually dissolve to form channels. The binder is prepared by adding PVA1788, PVA1799, glycerol, acrylic acid, and alkalized acrylic acid in sequence at a water temperature of 65-80 degrees Celsius, with an addition ratio of 100:20:4:3:2.

[0015] This invention provides a self-cleaning filler for constructed wetlands and its preparation method. It comprises a skeleton layer integrally formed of ceramsite and filler, using diatomaceous earth-type ceramsite as the skeleton. This fully utilizes the compressive strength and porous structure of the ceramsite. Fluorescent Pseudomonas aeruginosa and starch are then infused into the filler. During the growth and reproduction of the microorganisms—Fluorescent Pseudomonas aeruginosa—starch provides essential carbon and glucose sources. The pores within the ceramsite store the microorganisms and starch. Later, as the microorganisms and starch flow out, the vacant spaces can utilize the adsorption properties of diatomaceous earth to adsorb excess phosphorus from the water. Fluorescent Pseudomonas aeruginosa is then selected for further adsorption. Cytobacteria significantly reduce the dominance of harmful bacteria such as Rhizopus, Mucor, Trichoderma, and Aspergillus in the microbial community through antagonism, competition, and phagocytosis among microorganisms. At the same time, it greatly reduces the number of molds attached to gravel and volcanic rock. Dead microorganisms no longer attach to the surface of the original filler and will flow away from the wetland with the water flow. Meanwhile, with diatomaceous earth-type ceramsite as the skeleton, the volume of the entire filler does not decrease and will not collapse, which can improve the peristaltic microenvironment of plants growing in the wetland and reduce the water flow velocity in the wetland to a minimum. It employs a vacuum pressurization method to inject *Pseudomonas fluorescens* and starch into the ceramsite, allowing the starch to provide the growth potential for *Pseudomonas fluorescens* during the formation of the artificial wetland filler. Through antagonism, competition, and phagocytosis among microorganisms, the dominance of unwanted microorganisms such as *Rhizopus*, *Mucor*, *Trichoderma*, and *Aspergillus* in the microbial community is significantly reduced. Simultaneously, the amount of mold adhering to gravel and volcanic rock is greatly reduced. Furthermore, a binder is added during the granulation process, and the raw materials used in the original filler are infused with corn fiber. After the binder forms the ceramsite skeleton layer, it fixes each layer to the outer layer of the ceramsite. Because the binder PAV (polyvinyl alcohol) is a water-soluble polymer... In room temperature water, PVA-1788 dissolves faster than PVA-1799, so PVA-1788 dissolves first. After soaking the corn fiber in the PVA-1788 solution for 20 minutes, it is removed, air-dried, and then broken into flocculent particles. It is then mixed with peat moss, clay, iron powder, and zeolite powder to form the first and second coating layers. At room temperature, the soaked corn fiber degrades first and then gradually dissolves on the outside of the skeleton layer, forming multiple channels. These channels release the microorganisms and starch stored inside the ceramsite. Only by releasing the internal microorganisms can the useless microorganisms be killed, preventing blockage of the gaps between the fillers in the wetland.

[0016] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention after the channel is formed; Figure 3 This is a schematic diagram of the ceramsite in the ceramsite body of the present invention; Figure 4 This is a schematic diagram of the internal structure of the ceramsite of the present invention; Figure 5 This is a schematic diagram illustrating the preparation of the skeleton layer of the present invention.

[0018] In the diagram: 1. Skeleton layer, 2. First coating layer, 3. Second coating layer, 4. Infiltrated corn fiber, 5. Channel. Detailed Implementation

[0019] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] Example 1: See Figure 1-4 This invention provides a self-cleaning filler for artificial wetlands and its preparation method, comprising: The skeleton layer 1 includes ceramsite and filler, which are integrally formed. The ceramsite is composed of multiple ceramsite particles, and the filler is a mixture of microbial strains and starch. The first covering layer 2 is disposed around the outside of the skeleton layer 1; The second covering layer 3 is disposed around the outside of the first covering layer 3; Corn fiber 4 is impregnated and mixed inside the first coating layer 2 and the second coating layer 3; Channel 5 is pre-formed in multiple ways, with one end of each channel 5 extending into the interior of the skeleton layer 1 and the other end extending into the exterior of the second covering layer 3.

[0021] This embodiment provides a self-cleaning filler for artificial wetlands, which has a skeleton layer 1 formed by an integral ceramsite body and filler. Diatomaceous earth-type ceramsite serves as the skeleton, fully utilizing the compressive strength and porous structure of the ceramsite. Fluorescent Pseudomonas aeruginosa and starch are then injected into it. During the growth and reproduction of the microorganisms—Fluorescent Pseudomonas aeruginosa—starch is used to replenish the carbon source and glucose required by the microorganisms. The pores in the ceramsite store the microorganisms and starch. Later, as the microorganisms and starch flow out, the vacant spaces can utilize the adsorption properties of diatomaceous earth to adsorb excess phosphorus from the water. Fluorescent Pseudomonas aeruginosa is selected as a dominant bacterial group in the wetland, which is not conducive to the purification of wastewater and the decomposition of nutrients required by crops. Through antagonism, competition, and phagocytosis among the microorganisms... This method significantly reduces the dominance of harmful microorganisms such as Rhizopus, Mucor, Trichoderma, and Aspergillus in the microbial community, while also greatly reducing the amount of mold attached to gravel and volcanic rock. Dead microorganisms no longer adhere to the surface of the original packing material. Furthermore, using diatomaceous earth-type ceramsite as the framework ensures that the overall volume of the packing material does not decrease and collapse is prevented. This improves the peristaltic microenvironment for plants growing in the wetland and minimizes water flow velocity. The self-cleaning packing material provided in this embodiment is selected as 20%-25% of the total packing material volume, with the remaining packing material consisting of common materials such as gravel and volcanic rock. The self-cleaning packing material provided in this embodiment ensures that dead microorganisms no longer adhere to the surface of the original packing material, thus improving the peristaltic microenvironment for plants growing in the wetland.

[0022] In a further embodiment of this example, the ceramsite is set as diatomaceous earth type ceramsite, the particle size of the diatomaceous earth type ceramsite is 0.5-1.5cm, the porosity of the diatomaceous earth type ceramsite is 65-72%, and the compressive strength is 0.2-0.3Mpa.

[0023] In this embodiment, the pores inside the diatomaceous earth-type ceramsite can store microorganisms and starch, and the diatomaceous earth-type ceramsite serves as a skeleton, so the volume of the entire filler does not decrease and will not collapse.

[0024] In a further embodiment of this invention, the microbial strain is set as *Pseudomonas fluorescens*, the starch is set as β-starch, and the microbial strain and starch mixture are mixed in a ratio of 1:25 to 1:30.

[0025] In this embodiment, β-starch replenishes the carbon source and glucose required by microorganisms. The growth and reproduction of microorganisms require nutrients such as C, H, O, N, S, P, cellulose, hemicellulose, and glucose. In constructed wetlands, starch is used to replenish the carbon source and glucose required by microorganisms. Other elements are present in the water and are precisely what needs to be removed. Therefore, adding starch is precisely to replenish the elements lacking in the water, which enables microorganisms to expand and reproduce. β-starch is used because it is a pregelatinized starch, which can be better decomposed and utilized by microorganisms. Fluorescent Pseudomonas is selected as a dominant bacterial group in wetlands that is not conducive to the purification of sewage and the decomposition of nutrients required by crops. Through antagonism, competition, and phagocytosis among microorganisms, the dominance of useless bacterial groups such as Rhizopus, Mucor, Trichoderma, and Aspergillus in the microbial community is greatly reduced, while the number of molds attached to gravel and volcanic rock is also greatly reduced.

[0026] As a preferred embodiment of the above technical solution, the first coating layer 2 is a mixture of peat moss, impregnated corn fiber, and clay, and the second coating layer 3 is a mixture of iron powder, zeolite powder, impregnated corn fiber, and clay. The length of a single impregnated corn fiber is 0.2-0.3 mm, and the mass ratio of the impregnated corn fiber to the first coating layer 2 and the second coating layer 3 is 100:0.6-100:1.0, respectively.

[0027] In this embodiment, the first coating layer 3 and the second coating layer 4 coat the inner skeleton layer 1, making the whole unit integrated. Furthermore, the raw materials used in the original filler are supplemented with impregnated corn fiber, as shown in the attached drawings. Figure 1 The corn fiber is unevenly soaked on the outside of the skeleton layer 1. After soaking in the PVA-1788 solution for 20 minutes, the corn fiber is removed, air-dried, and then broken into flocculent particles. It is then mixed with peat moss, clay, iron powder, and zeolite powder to form the first coating layer 2 and the second coating layer 3. The dissolution rate (time) of PVA-1788 is faster than that of PVA-1799, so PVA-1788 dissolves first. At room temperature, the soaked corn fiber degrades first and then gradually dissolves to form channels 5. Microorganisms and starch stored inside the ceramsite are released through multiple channels 5. In the later stage, as the microorganisms and starch flow out, the gaps can be used to adsorb excess phosphorus in the water by utilizing the adsorption properties of diatomaceous earth.

[0028] Example 2: Refer to the attached diagram in the instruction manual. Figure 5 The present invention also provides a method for preparing self-cleaning filler for artificial wetlands, specifically including the following steps: Step 1: Select multiple ceramsites, select microbial strains and starch mixtures in proportion, and prepare filler 2; Step 2: Fill the sealed chamber with diatomaceous earth-type ceramsite, turn on the vacuum pump to evacuate the sealed chamber, and turn off the vacuum pump after evacuation. The vacuum degree during the operation of the vacuum pump is 0.08 MPa and the time is 5-10 minutes. Step 3: Open the valve to add the microbial inoculum and starch mixture into the chamber, then close the valve and add the microbial inoculum and starch mixture, filling the chamber to 60% of its volume. Step 4: Turn on the pressure pump to pressurize the sealed chamber and mix the filler 2 and the ceramsite 1 into one. During the operation of the pressure pump, pressurize the inside of the sealed chamber to 0.2 MPa. This can be repeated multiple times, with each time lasting 5-20 minutes. Step 5: Granulate the ceramsite that has been injected with bacterial agent and starch, and add a binder during the granulation process. After granulation, the filler is dried by hot air to gradually shape it. The hot air drying is done by a hot air blower with an outlet temperature of 45-55 degrees Celsius. Step Six: Select an area of ​​appropriate size for the molded ceramsite and filler mixture according to the required wetland size. After soaking the corn fiber in PVA-1788 solution for 20 minutes, remove it, air dry it, break it into flocculent state, and mix it with peat moss, clay, iron powder, and zeolite powder to form the first coating layer 2 and the second coating layer 3. Then, coat the outside of the first coating layer 2 and the second coating layer 3 in sequence, and then dry it to complete the preparation of the entire artificial wetland self-cleaning filler.

[0029] This embodiment provides a method for preparing self-cleaning filler for constructed wetlands. It involves injecting *Pseudomonas fluorescens* and starch into ceramsite under vacuum pressure. During the formation of the filler, the starch provides the necessary energy for the growth of *Pseudomonas fluorescens*. Through antagonism, competition, and phagocytosis among the microorganisms, the dominance of unwanted microorganisms such as *Rhizopus*, *Mucor*, *Trichoderma*, and *Aspergillus* in the microbial community is significantly reduced. Simultaneously, the amount of mold adhering to gravel and volcanic rock is greatly reduced. Furthermore, a binder is added during the granulation process, and the raw materials used in the original filler are infiltrated with corn fiber. After the filler forms the ceramsite skeleton layer, the binder fixes each layer to the outer layer of the ceramsite. Since the binder PAV (polyvinyl alcohol) is a water-soluble polymer material, PVA-178... 8. The dissolution rate (time) is faster than PVA-1799, so PVA-1788 dissolves first. After soaking the corn fiber in the PVA-1788 solution for 20 minutes, it is removed, air-dried, and then broken into flocculent particles. It is then mixed with peat moss, clay, iron powder, and zeolite powder to form the first coating layer 2 and the second coating layer 3. At room temperature, the soaked corn fiber degrades first and then gradually dissolves on the outside of the skeleton layer 1, forming multiple channels 5. The microorganisms and starch stored inside the ceramsite are released through multiple channels 5. Only by releasing the internal microorganisms can the useless microorganisms be killed, preventing the blockage of the gap channels 5 between the fillers in the wetland. After about 10 years, all the outer coating layers of the ceramsite will be released, leaving only diatomaceous earth type ceramsite. The volume of the entire filler will not decrease and there will be no collapse.

[0030] In a further embodiment of this example, the binder in step five is set as a polyvinyl alcohol solvent, the ratio of water to PVA is 1:8:-1:10, the temperature of the aqueous solution is set to 40-50 degrees Celsius, and the ratio of PVA-1788 to PVA-1799 is 2:7:-3:8.

[0031] In this embodiment, the binder gradually dissolves in room temperature water, forming multiple channels 5 on the outside of the skeleton layer 1.

[0032] In a further embodiment of this example, after the binder forms the filler in the ceramsite skeleton layer 1, it will fix each layer on the outer layer of the ceramsite. Under normal temperature conditions, the corn fiber will degrade first and then gradually dissolve to form channels 5. The binder is prepared by adding PVA1788, PVA1799, glycerol, acrylic acid, and alkalized acrylic acid in sequence at a water temperature of 65-80 degrees Celsius, with an addition ratio of 100:20:4:3:2.

[0033] In this embodiment, multiple channels 5 release the microorganisms and starch stored inside the ceramsite. Only by releasing the internal microorganisms can the useless microorganisms be killed, preventing blockage of the gap channels between the fillers in the wetland. After about 10 years, all the outer coating layers of the ceramsite will be released, leaving only diatomaceous earth-type ceramsite. The volume of the entire filler will not decrease, and no collapse will occur.

[0034] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this invention should be included within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A method for preparing a self-cleaning filler for artificial wetlands, characterized in that, The self-cleaning filler for the constructed wetland includes a skeleton layer (1), comprising ceramsite and filler, wherein the ceramsite and filler are integrally formed, the ceramsite being composed of multiple ceramsite particles, and the filler being a mixture of microbial strains and starch; a first coating layer (2), surrounding the outside of the skeleton layer (1); a second coating layer (3), surrounding the outside of the first coating layer (2); impregnated corn fiber (4), mixed and disposed inside the first coating layer (2) and the second coating layer (3); and channels (5), pre-formed as... Multiple channels (5) extend one end into the interior of the skeleton layer (1) and the other end into the outside of the second coating layer (3); the first coating layer (2) is a mixture of peat moss, impregnated corn fiber and clay, and the second coating layer (3) is a mixture of iron powder, zeolite powder, impregnated corn fiber and clay, with the length of a single impregnated corn fiber being 0.2-0.3 mm; the microbial strain is set as fluorescent Pseudomonas aeruginosa, the starch is set as β-starch, and the microbial strain and starch mixture are mixed in a ratio of 1:25-1:30; The preparation method includes the following steps: Step 1: Select multiple ceramsites, and select a mixture of microbial strains and starch in a certain proportion to prepare a filler; Step 2: Fill the sealed chamber with diatomaceous earth-type ceramsite, turn on the vacuum pump to evacuate the chamber, and turn off the vacuum pump after the evacuation is complete. Step 3: Open the valve to add the mixture of microbial inoculum and starch into the chamber, then close the valve; Step 4: Turn on the pressure pump to pressurize the sealed chamber and mix the filler with the ceramsite to form a skeleton layer (1); Step 5: Granulate the ceramsite that has been injected with microbial agent and starch, and add a binder during the granulation process. After granulation, the filler is dried by hot air and gradually shaped. Step 6: Select an area of ​​appropriate size for the shaped ceramsite and filler mixture according to the required wetland. After soaking the corn fiber in PVA-1788 solution for 20 minutes, remove it, air dry it, break it into flocculent state, and mix it with peat moss, clay, iron powder, and zeolite powder to form the first coating layer (2) and the second coating layer (3). Then, coat the outside of the first coating layer (2) and the second coating layer (3) in sequence, and then dry it to complete the preparation of the entire artificial wetland self-cleaning filler. After the binder forms the filler in the ceramsite skeleton layer, it will fix each layer on the outer layer of the ceramsite. Under normal temperature conditions, the corn fiber will degrade first and then gradually dissolve to form channels (5). The binder is prepared by adding PVA1788, PVA1799, glycerol, acrylic acid, and alkalized acrylic acid in sequence at a water temperature of 65-80 degrees Celsius, with an addition ratio of 100:20:4:3:

2.

2. The method for preparing a self-cleaning filler for artificial wetlands according to claim 1, characterized in that, The ceramsite is set as diatomaceous earth type ceramsite, with a particle size of 0.5-1.5 cm, a porosity of 65-72%, and a compressive strength of 0.2-0.3 MPa.

3. The method for preparing a self-cleaning filler for artificial wetlands according to claim 2, characterized in that, In step two, the vacuum pump operates at a vacuum level of 0.08 MPa for 5-10 minutes. In step four, the pressurizing pump pressurizes the sealed chamber to 0.2 MPa, which can be repeated multiple times, with each pressurization lasting 5-20 minutes.

4. The method for preparing a self-cleaning filler for artificial wetlands according to claim 3, characterized in that, In step three, a mixture of microbial inoculum and starch is added, filling the volume to 60% of the sealed chamber volume.

5. The method for preparing a self-cleaning filler for artificial wetlands according to claim 4, characterized in that, In step five, hot air drying is performed using a hot air blower with an outlet air temperature of 45-55 degrees Celsius.

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