A bio-friendly substrate for submerged plant colonization and its preparation method

Abstract

This application relates to the field of sediment ecological restoration and discloses a bio-friendly submerged plant planting substrate and a preparation method thereof; the planting substrate includes: an oxygen release layer, a plant growth layer, a condensation layer, and a fixing layer; the preparation method includes S1: mixing calcium peroxide, ammonia-oxidizing archaea, and solid oxygen in a preset ratio to form an oxygen release layer; S2: mixing plant seeds and a plant growth substrate in a preset ratio to form a plant growth layer; S3: mixing xanthan gum and carrageenan in a preset ratio, and coating the formed gel on the connection surface and the periphery between the oxygen release layer and the plant growth layer to form a condensation layer; S4: making a fixing layer with a biodegradable material to wrap the whole planting substrate; S5: cultivating the submerged plant seeds in the planting substrate on the shore. The oxygen release layer in this application greatly increases the redox potential of the sediment, improves the anaerobic state of the sediment, and the materials used are all bio-friendly materials, reducing secondary pollution to the environment.

Description

Technical Field

[0001] The present application relates to the field of sediment ecological restoration, and particularly to a bio-friendly submerged plant planting substrate and a preparation method thereof. Background Art

[0002] After external pollution is discharged into water bodies, a small part of the pollutants can be purified by the self-purification function of the water bodies, while most of them settle to form bottom sediments, which easily form black and odorous sludge after long-term accumulation. The heavy metals inside the black and odorous sludge are likely to cause toxic effects on the growth of plants.

[0003] In order to reduce the secondary pollution of the environment caused by the black and odorous sludge carrying heavy metals, in-situ treatment technologies are currently used to treat the polluted sediment. Existing in-situ treatment technologies are all carried out around various enhanced oxygen supply measures, such as biogas flushing technology, dissolved air water oxygen supply technology, and hydrogen peroxide oxygen supply technology, etc. These in-situ treatment technologies have complicated steps, long construction time, and require relatively professional technical personnel, and cannot be popularized on a large scale.

[0004] To overcome the defects of existing in-situ treatment technologies, submerged plants can be used to repair the polluted sediment. Submerged plants refer to aquatic plants whose entire bodies are located below the water layer and live in a fixed state. The planting substrate refers to the nutrients and supporting environment required for plant growth and development, and plays an important role in supporting the plant roots and storing nutrients. The planting substrate of submerged plants can be prepared for the repair of black and odorous sludge to overcome the defects of complicated steps and long construction time in existing in-situ treatment technologies. Summary of the Invention

[0005] By providing a bio-friendly submerged plant planting substrate and a preparation method thereof in the embodiments of the present application, the technical problems of complicated steps and long construction time in existing in-situ treatment technologies for black and odorous sludge are solved. The redox potential of the sediment is greatly increased by using the oxygen release layer, the anaerobic state of the sediment is improved, a favorable growth environment is provided for the planting of submerged plants, and the polluted sediment is repaired by using the submerged plants. Moreover, the materials used are all bio-friendly materials, reducing secondary pollution to the environment.

[0006] The embodiments of the present application provide a bio-friendly submerged plant planting substrate, including: an oxygen release layer, including calcium peroxide, ammonia-oxidizing archaea, and solid oxygen; a plant growth layer, including plant seeds and a plant growth substrate, and the plant growth layer is located above the oxygen release layer; a coagulation layer, formed by mixing xanthan gum and carrageenan, and the formed gel is coated on the connection surface and around the oxygen release layer and the plant growth layer; a fixing layer, made of a degradable material and wrapped outside the coagulation layer.

[0007] Further, the mixing ratio of calcium peroxide, ammonia-oxidizing archaea, and solid oxygen in the oxygen-releasing layer is 7-9:0.5-1.5:5-7.

[0008] Further, the plant growth substrate includes perlite, fine sand, biochar, nutrient soil, and local soil, and the mass ratio is 2-3:0.5-1:0.5-1:20-30:30-35.

[0009] Further, the mixing ratio of xanthan gum and carrageenan in the condensation layer is 2:3.

[0010] Further, before using the bio-friendly submerged plant colonization substrate, microporous treatment is carried out, with the pore diameter being 50-100 microns, and the pore diameter on the upper surface of the plant growth layer being 1-2 cm.

[0011] This application also provides a method for preparing a bio-friendly submerged plant colonization substrate. The preparation method includes: S1: Mix calcium peroxide, ammonia-oxidizing archaea, and solid oxygen according to a preset ratio, and then press them into blocks under a hydraulic press to form an oxygen-releasing layer; S2: Mix plant seeds and a plant growth substrate according to a preset ratio, and then press them into blocks under a hydraulic press to form a plant growth layer; S3: Mix xanthan gum and carrageenan according to a preset ratio, and coat the formed gel on the connection surface and around between the oxygen-releasing layer and the plant growth layer to form a condensation layer; S4: Make a fixing layer with a biodegradable material and wrap the entire bio-friendly submerged plant colonization substrate; S5: Carry out the development culture of the submerged plant seeds in the colonization substrate on the shore. After developing to a preset stage, the colonization substrate can be put into the water.

[0012] Further, before putting the colonization substrate into the water, microporous treatment is carried out on the colonization substrate, with the pore diameter being 50-100 microns, and the pore diameter on the upper surface of the plant growth layer being 1-2 cm.

[0013] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0014] Since the oxygen-releasing layer, plant growth layer, condensation layer, and fixing layer are used as the colonization substrate, after the colonization substrate is put into the water, the oxygen-releasing layer releases oxygen when encountering water. The ammonia-oxidizing archaea can survive by generating oxygen on its own, continuously providing oxygen for the anaerobic bottom mud environment. The solid oxygen can kill harmful bacteria in the water body and inhibit the growth of algae, greatly increasing the redox potential of the bottom mud, improving the anaerobic state of the bottom mud, providing a favorable growth environment for the colonization of submerged plants, being able to repair the polluted bottom mud, and not causing secondary pollution to the environment, solving the technical problems of complex steps and long construction time in the existing in-situ treatment technology for black and odorous sludge. Description of the Drawings

[0015] Figure 1 It is a structural diagram of a bio-friendly submerged plant planting substrate in an embodiment of the present application;

[0016] Figure 2 It is a schematic diagram of sediment-related indicators obtained through experiments in an embodiment of the present application;

[0017] Figure 3 It is a flowchart of a method for preparing a bio-friendly submerged plant planting substrate in an embodiment of the present application.

[0018] In the figure: 1. Oxygen release layer; 2. Plant growth layer; 3. Coagulation layer; 4. Fixing layer. Detailed implementation manners

[0019] An embodiment of the present application discloses a bio-friendly submerged plant planting substrate, including: an oxygen release layer 1, including calcium peroxide, ammonia-oxidizing archaea, and solid oxygen; a plant growth layer 2, including plant seeds and a plant growth substrate, and the plant growth layer 2 is located above the oxygen release layer 1; a coagulation layer 3, formed by mixing xanthan gum and carrageenan, and the formed gel is coated on the connection surface and around between the oxygen release layer 1 and the plant growth layer 2; a fixing layer 4, made of a degradable material and wrapped outside the coagulation layer 3. It solves the technical problems of complicated steps and long construction time in the existing in-situ treatment technology for black and odorous sludge, and realizes that the oxygen release layer 1 greatly improves the redox potential of the sediment, improves the anaerobic state of the sediment, and provides a favorable growth environment for the planting of submerged plants.

[0020] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the specification drawings and specific implementation manners.

[0021] The present application provides a bio-friendly submerged plant planting substrate, referring to Figure 1 As shown, the planting substrate includes an oxygen release layer 1, a plant growth layer 2, a coagulation layer 3, and a fixing layer 4.

[0022] The oxygen-releasing layer 1 can be composed of calcium peroxide, ammonia-oxidizing archaea, and solid oxygen, and the mixing ratio is 7-9:0.5-1.5:5-7. After the oxygen-releasing layer 1 comes into contact with moisture, it will slowly release oxygen. As a bio-friendly material, calcium peroxide has the property of releasing oxygen when encountering water, is non-toxic itself, does not pollute the environment, and can also adjust the pH value of water, improve water quality, and eliminate pathogenic bacteria. It is an excellent oxygen-supplying agent with a wide range of uses. Ammonia-oxidizing archaea are microorganisms that can survive by generating oxygen on their own in a dark and oxygen-deficient environment, and can continuously supply oxygen to the anaerobic sediment environment. Solid oxygen is a light blue solid crystal transformed when liquid oxygen is cooled to 54.35K (-218.8 °C), with a snowflake shape. It can slowly release oxygen in water, has the ability to sterilize, can kill harmful bacteria in the water body and inhibit the growth of algae. Solid oxygen has a strong absorption capacity for various substances fatal to aquatic organisms such as ammonia and nitrite, and has a certain acid-base buffering capacity.

[0023] The plant growth layer 2 is located above the oxygen-releasing layer 1. The plant growth layer 2 can be composed of plant seeds and a plant growth substrate. The plant growth substrate can include perlite, fine sand, biochar, nutrient soil, and local soil, and the mass ratio is 2-3:0.5-1:0.5-1:20-30:30-35. The local soil is obtained locally depending on where the planting substrate will be applied. The plant seeds are submerged plant seeds, and the submerged plant seeds can be one or more of Potamogeton crispus, Potamogeton malaianus, Potamogeton pectinatus, Potamogeton maackianus, Elodea nuttallii, Hydrilla verticillata, Ceratophyllum demersum, Myriophyllum verticillatum, and Vallisneria natans.

[0024] The coagulation layer 3 can be formed by mixing xanthan gum and carrageenan, and the mixing ratio is 2:3. The formed gel is coated on the connection surface and around between the oxygen-releasing layer 1 and the plant growth layer 2, which can improve the firmness between the oxygen-releasing layer 1 and the plant growth layer 2, and also improve the firmness of the oxygen-releasing layer 1 and the plant growth layer 2 itself. In addition, xanthan gum is a stable extracellular metabolite of microorganisms. After complete hydrolysis, it can obtain glucose, mannose, and glucuronic acid. Carrageenan is mainly obtained from seaweeds of varieties such as Chondrus, Eucheuma, Gigartina, and Hypnea of lower cryptogams. Therefore, both xanthan gum and carrageenan are natural components, which not only do not affect the environment, but also can provide nutrients for plants and microorganisms after decomposition.

[0025] The fixed layer 4 can be made of polylactic acid degradable material. After coating the gel formed by mixing xanthan gum and carrageenan on the joint surface and around between the oxygen-releasing layer 1 and the plant growth layer 2, the wrapper made of polylactic acid degradable material is coated outside the coagulation layer 3 to realize the wrapping of the oxygen-releasing layer 1 and the plant growth layer 2. After the planting substrate is put into the water, the fixed layer 4 can decompose by itself in about one month, thus not causing secondary pollution to the environment. In addition, before putting the planting substrate into the water, micropore treatment is carried out on the fixed layer 4, the pore diameter is 50-100 microns, and the pore diameter on the upper surface of the plant growth layer 2 is 1-2 cm. The large pore diameter can reduce the impact on the growth of plants.

[0026] For different mixing ratios among calcium peroxide, ammonia-oxidizing archaea and solid oxygen in the oxygen-releasing layer 1, and different mixing ratios among perlite, fine sand, biochar, nutrient soil and local soil in the plant growth substrate, the sediment is repaired, and at the time nodes of the 30th day and the 60th day, samples are taken for detection, and the thickness, pH value and ORP value of the sediment are detected.

[0027] The initial thickness of the sediment is 12.8 cm, the initial pH value is 6.9, and the initial ORP value is -267 mv.

[0028] Blank group: Do not put the bio-friendly submerged plant planting substrate of the present application into the water body.

[0029] Experimental group 1: Put the bio-friendly submerged plant planting substrate of the present application into the water body, and the mixing ratio of calcium peroxide, ammonia-oxidizing archaea and solid oxygen in the oxygen-releasing layer 1 is: 7:0.5:5, and the mixing ratio of perlite, fine sand, biochar, nutrient soil and local soil in the plant growth substrate is: 2:0.5:0.5:20:30.

[0030] Experimental group 2: Put the bio-friendly submerged plant planting substrate of the present application into the water body, and the mixing ratio of calcium peroxide, ammonia-oxidizing archaea and solid oxygen in the oxygen-releasing layer 1 is: 8:1:6, and the mixing ratio of perlite, fine sand, biochar, nutrient soil and local soil in the plant growth substrate is: 2.5:0.5:1:25:30.

[0031] Experimental group 3: Put the bio-friendly submerged plant planting substrate of the present application into the water body, and the mixing ratio of calcium peroxide, ammonia-oxidizing archaea and solid oxygen in the oxygen-releasing layer 1 is: 9:1.5:7, and the mixing ratio of perlite, fine sand, biochar, nutrient soil and local soil in the plant growth substrate is: 3:1:0.5:30:35.

[0032] Figure 2Regarding the sediment - related indicators, it can be seen from the experimental data that the sediment - related indicators obtained in experimental group 3 are closest to the healthy water body standard. Therefore, the mixing ratio of calcium peroxide, ammonia - oxidizing archaea, and solid oxygen in oxygen - releasing layer 1 is set as: 9:1.5:7, and the mixing ratio of perlite, fine sand, biochar, nutrient soil, and local soil in the plant growth substrate is set as: 3:1:0.5:30:35, which is the optimal ratio of the bio - friendly submerged plant planting substrate.

[0033] This application provides a method for preparing a bio - friendly submerged plant planting substrate. Referring to Figure 3 as shown, the preparation method includes:

[0034] S1: Mix calcium peroxide, ammonia - oxidizing archaea, and solid oxygen according to a preset ratio, and then press them into blocks under a hydraulic press to form oxygen - releasing layer 1.

[0035] S2: Mix plant seeds and the plant growth substrate according to a preset ratio, and then press them into blocks under a hydraulic press to form plant growth layer 2.

[0036] S3: Mix xanthan gum and carrageenan according to a preset ratio, and coat the formed gel on the connection surface and around the periphery between oxygen - releasing layer 1 and plant growth layer 2 to form coagulation layer 3.

[0037] S4: Make a fixing layer 4 from a biodegradable material and wrap the whole bio - friendly submerged plant planting substrate.

[0038] S5: Conduct the developmental cultivation of the submerged plant seeds in the planting substrate on the shore. After developing to a preset stage, the planting substrate can be put into the water.

[0039] In addition, before putting the planting substrate into the water, perform microporous treatment on the planting substrate. The pore diameter is 50 - 100 microns, and the pore diameter on the upper surface of plant growth layer 2 is 1 - 2 cm.

[0040] The functional principle of this application can be elaborated through the following operation method: Use one or more of Potamogeton crispus, Potamogeton malaianus, Potamogeton pectinatus, Potamogeton maackianus, Elodea nuttallii, Hydrilla verticillata, Ceratophyllum demersum, Myriophyllum verticillatum, and Vallisneria natans as the plant seeds in plant growth layer 2, and put these seeds into the plant growth substrate composed of perlite, fine sand, biochar, nutrient soil, and local soil. Then place oxygen - releasing layer 1 composed of calcium peroxide, ammonia - oxidizing archaea, and solid oxygen in plant growth layer 2. Next, coat the gel formed by mixing xanthan gum and carrageenan on the connection surface and around the periphery between oxygen - releasing layer 1 and plant growth layer 2 to form coagulation layer 3. Finally, wrap fixing layer 4 made of polylactic acid biodegradable material outside coagulation layer 3, thereby forming a bio - friendly submerged plant planting substrate.

[0041] After the colonization substrate is put into water, the oxygen-releasing layer 1 releases oxygen when encountering water. The ammonia-oxidizing archaea can survive by generating oxygen on their own, continuously providing oxygen for the anaerobic sediment environment. The solid oxygen can kill harmful bacteria in the water body and inhibit the growth of algae. The solid oxygen has a strong absorption capacity for various substances fatal to aquatic organisms such as ammonia and nitrite, and has a certain acid-base buffering capacity, greatly increasing the redox potential of the sediment, improving the anaerobic state of the sediment, providing a favorable growth environment for the colonization of submerged plants, being able to repair the polluted sediment, and the materials used are all bio-friendly materials and will not cause secondary pollution to the environment.

[0042] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to include these modifications and variations.

[0043] As described above, it is only the preferred specific implementation manner of the embodiments of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application, according to the technical solution and its concept of this application, makes equivalent substitutions or changes, and should be covered by the protection scope of this application.

Claims

1. A bio-friendly substrate for submerged plant colonization, characterized in that, Comprising: An oxygen-releasing layer (1), including calcium peroxide, ammonia-oxidizing archaea, and solid oxygen; A plant growth layer (2), including plant seeds and a plant growth substrate, and the plant growth layer (2) is located above the oxygen-releasing layer (1); A condensation layer (3), formed by mixing xanthan gum and carrageenan, and the formed gel is coated on the joint surface and the periphery between the oxygen-releasing layer (1) and the plant growth layer (2); A fixing layer (4), made of a degradable material, and wrapped outside the condensation layer (3).

2. The bio-friendly submerged plant planting substrate according to claim 1, wherein, The ratio of calcium peroxide, ammonia-oxidizing archaea, and solid oxygen in the oxygen-releasing layer (1) is 7-9:0.5-1.5:5-7.

3. The bio-friendly submerged plant planting substrate according to claim 1, characterized in that, The plant growth substrate includes perlite, fine sand, biochar, nutrient soil, and local soil, and the mass ratio is 2-3:0.5-1:0.5-1:20-30:30-35.

4. The bio-friendly submerged plant planting substrate according to claim 1, wherein, The ratio of xanthan gum and carrageenan in the condensation layer (3) is 2:

3.

5. A bio-friendly submerged plant planting substrate according to claim 1, characterized in that, Before using the bio-friendly submerged plant colonization substrate, micropore treatment is carried out, with the pore diameter being 50-100 microns, and the pore diameter on the upper surface of the plant growth layer (2) being 1-2 cm.

6. A preparation method of a bio-friendly submerged plant colonization substrate, characterized in that, The preparation method includes: S1: Mix calcium peroxide, ammonia-oxidizing archaea, and solid oxygen in a preset ratio, and then press them into a block under a hydraulic press to form the oxygen-releasing layer (1); S2: Mix plant seeds and a plant growth substrate in a preset ratio, and then press them into a block under a hydraulic press to form the plant growth layer (2); S3: Mix xanthan gum and carrageenan in a preset ratio, and coat the formed gel on the joint surface and the periphery between the oxygen-releasing layer (1) and the plant growth layer (2) to form the condensation layer (3); S4: Make a fixing layer (4) with a degradable material and wrap it outside the condensation layer (3); S5: Carry out the development and cultivation of submerged plant seeds in the colonization substrate on the shore. After developing to a preset stage, put the colonization substrate into the water.

7. The preparation method of a bio-friendly submerged plant planting substrate according to claim 6, wherein, Before putting the colonization substrate into the water, carry out micropore treatment on the colonization substrate, with the pore diameter being 50-100 microns, and the pore diameter on the upper surface of the plant growth layer (2) being 1-2 cm.

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