Sludge hydrothermal carbonization slurry ecological restoration bed as well as preparation method and application thereof

Abstract

The invention relates to the field of environmental governance, in particular to a sludge hydrothermal carbonization slurry ecological restoration bed as well as a preparation method and application thereof. The sludge hydrothermal carbonization slurry ecological restoration bed comprises 100 parts of sludge hydrothermal carbonization slurry, 5-12 parts of plant fibers, 10-50 parts of soil, 0.01-0.1 part of a water-retaining agent, 1-10 parts of cement, 1-15 parts of lime and 0.1-1 part of plant seeds. According to the sludge hydrothermal carbonization slurry ecological restoration bed, municipal sludge is directly modified to generate biochar slurry, the biochar slurry not only has nutrient elements such as clay, nitrogen, phosphorus and potassium, but also has a porous structure of biochar, moisture and entropy are preserved, plant growth is promoted, plant fibers, basic soil, a water-retaining agent, cement and lime are assisted, rapid solidification is achieved, a vegetation bed is constructed, and the ecological restoration bed has a good ecological restoration effect. The mining area ecology is quickly restored. The material, technical composition and operation are simple and practical, and the method is suitable for large-area construction application.

Description

Technical Field

[0001] This invention relates to the field of environmental remediation, and in particular to an ecological remediation bed of sludge hydrothermal carbonization slurry, its preparation method, and its application. Background Technology

[0002] With the acceleration of urbanization and the expansion of sewage treatment scale, the output of municipal sludge is increasing year by year, and its treatment and disposal has become a major challenge in the field of environmental protection. Traditional sludge disposal methods, such as landfill and incineration, have problems such as large land occupation, high risk of secondary pollution, and low resource utilization. On the other hand, mineral resource mining has led to large areas of exposed land, soil erosion, and ecosystem degradation, making the task of mine ecological restoration arduous. Currently used restoration technologies, such as topsoil spraying, vegetation bags, and vegetation concrete, often suffer from problems such as high cost, limited soil sources, and insufficient long-term stability.

[0003] Hydrothermal carbonization is a green technology that converts organic matter into biochar under subcritical water conditions, enabling the reduction, stabilization, and resource recovery of sludge. Biochar possesses a porous structure, strong nutrient retention capacity, and good stability, making it suitable as a soil conditioner or remediation matrix. However, current research and application of sludge biochar directly in mine ecological restoration are insufficient, particularly lacking systematic integration in material formulation, construction technology, and long-term ecological benefits.

[0004] Therefore, developing an ecological restoration bed technology that uses sludge hydrothermal carbonization slurry as its core to achieve rapid solidification, water and fertilizer retention, and promote vegetation growth is of great environmental, economic, and social significance. Summary of the Invention

[0005] This invention provides a sludge hydrothermal carbonization slurry ecological restoration bed, its preparation method, and its application. Using sludge hydrothermal carbonization slurry as the main raw material, supplemented with plant fibers, soil, water-retaining agents, cement, lime, and plant seeds, the slurry is mixed, stirred, and sprayed to form an ecological restoration layer with good structural stability and vegetation support capacity on the surface to be restored. It can solidify rapidly, constructing a vegetated bed and quickly restoring the ecology of mining areas. The materials and technology of this invention are simple in composition and operation, practical, and suitable for large-scale construction applications.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a sludge hydrothermal carbonization slurry ecological remediation bed, comprising the following components in parts by weight: The ingredients are: 100 parts of hydrothermal carbonization slurry of sludge, 5-12 parts of plant fiber, 10-50 parts of soil, 0.01-0.1 parts of water-retaining agent, 1-10 parts of cement, 1-15 parts of lime, and 0.1-1 parts of plant seeds.

[0007] In some specific embodiments, the method for preparing the sludge hydrothermal carbonization slurry includes the following steps: The sludge undergoes a hydrothermal carbonization reaction in an acidic catalyst system to obtain a hydrothermal carbonization slurry.

[0008] In some specific embodiments, the sludge has a moisture content of 75% to 90%.

[0009] In some specific embodiments, the organic matter content in the sludge is 30% to 80%.

[0010] In some specific embodiments, the acidic catalyst includes a citric acid solution.

[0011] In some specific embodiments, the temperature of the hydrothermal carbonization reaction is 160~220℃, the time of the hydrothermal carbonization reaction is 2~6h, and the pressure of the hydrothermal carbonization reaction is 1~3MPa.

[0012] In some specific embodiments, the plant fiber includes crop straw and / or aquatic plants.

[0013] In some specific embodiments, the particle size of the plant fiber is 0.1~10mm.

[0014] In some specific embodiments, the particle size of the soil is 0.1~10mm.

[0015] In some specific embodiments, the water-retaining agent includes acrylamide-acrylate copolymer crosslinkers and / or starch-grafted acrylate copolymer crosslinkers.

[0016] In some specific embodiments, the plant seeds include herbaceous plant seeds.

[0017] In some specific embodiments, the cement includes PO42.5 cement.

[0018] In some specific embodiments, it also includes 1 to 5 parts of phosphate rock powder.

[0019] A second aspect of the present invention also provides a method for preparing the above-mentioned sludge hydrothermal carbonization slurry ecological remediation bed, comprising the following steps: Mix sludge hydrothermal carbonization slurry, plant fiber, soil, water-retaining agent, cement, lime and plant seeds.

[0020] In some specific implementations, phosphate rock powder is also added.

[0021] A third aspect of the present invention also provides an application of the above-mentioned sludge hydrothermal carbonization slurry ecological restoration bed in ecological restoration.

[0022] Compared with the prior art, the present invention has the following beneficial effects: This invention relates to a sludge hydrothermal carbonization slurry ecological restoration bed. The sludge hydrothermal carbonization slurry is used as the main raw material, supplemented with plant fibers, soil, water-retaining agents, cement, lime, and plant seeds. The sludge is transformed into high-value-added ecological restoration materials through hydrothermal carbonization, achieving waste resource utilization, reducing disposal costs, and avoiding secondary pollution. Furthermore, the biochar contained in the sludge hydrothermal carbonization slurry has a porous structure, effectively retaining water and fertilizer, and providing the necessary nutrients (nitrogen, phosphorus, potassium, etc.) for plant growth. Combined with the water-retaining agent and local soil, it significantly improves plant survival rate and growth rate. The addition of cement and lime enables the restoration layer to solidify rapidly, enhancing erosion resistance and slope stability, making it suitable for complex terrains such as steep slopes and high slopes. The addition of plant seeds promotes the natural restoration of the ecosystem and enhances biodiversity. In addition, the spraying process is suitable for large-area, mechanized construction, which is highly efficient and adaptable. Furthermore, all materials used are natural or environmentally friendly, and the plant seeds are selected from local dominant species, which is conducive to the natural restoration of the ecosystem and the enhancement of biodiversity. At the same time, the main raw materials are sludge and local soil, with less auxiliary materials used, and the overall cost is lower than that of traditional topsoil spraying and vegetation concrete technology. Attached Figure Description

[0023] The above and other objects, features, and advantages of the invention will be apparent from the following description of preferred embodiments illustrating the gist of the invention and its use, and the accompanying drawings, in which: Figure 1 This is a flowchart illustrating the preparation and application of the sludge hydrothermal carbonization slurry ecological restoration bed in this invention. Detailed Implementation

[0024] The present invention will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments described below are for illustrative purposes only and do not limit the scope of the invention in any way. Furthermore, in the following embodiments, unless otherwise specified, the reagents and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the following embodiments, conditions and methods known in the art can be used for processing.

[0025] This invention provides a sludge hydrothermal carbonization slurry ecological remediation bed, comprising the following components in parts by weight: The ingredients are: 100 parts of hydrothermal carbonization slurry of sludge, 5-12 parts of plant fiber, 10-50 parts of soil, 0.01-0.1 parts of water-retaining agent, 1-10 parts of cement, 1-15 parts of lime, and 0.1-1 parts of plant seeds.

[0026] This invention relates to a sludge hydrothermal carbonization slurry ecological restoration bed. The sludge hydrothermal carbonization slurry is used as the main raw material, supplemented with plant fibers, soil, water-retaining agents, cement, lime, and plant seeds. The sludge is transformed into high-value-added ecological restoration materials through hydrothermal carbonization, achieving waste resource utilization, reducing disposal costs, and avoiding secondary pollution. Furthermore, the biochar contained in the sludge hydrothermal carbonization slurry has a porous structure, effectively retaining water and fertilizer, and providing the nutrients (clay, nitrogen, phosphorus, potassium, etc.) required for plant growth. Combined with the water-retaining agent and local soil, it significantly improves plant survival rate and growth rate. The addition of cement and lime enables the restoration layer to solidify rapidly, while plant fibers help improve the toughness of the solidified soil, enhancing erosion resistance and slope stability, making it suitable for complex terrains such as steep slopes and high slopes. The addition of plant seeds promotes the natural restoration of the ecosystem and enhances biodiversity.

[0027] In some embodiments, the mass fraction of plant fiber can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, and 12 parts, etc.

[0028] In some embodiments, the mass fraction of soil may be 10 parts, 20 parts, 30 parts, 40 parts, and 50 parts, etc.

[0029] In some embodiments, the water-retaining agent may be present in parts by weight of 0.01, 0.02, 0.05, 0.07, 0.08, and 0.1 parts, etc.

[0030] In some embodiments, the mass fraction of cement can be 1 part, 2 parts, 5 parts, 7 parts, 8 parts, and 10 parts, etc.

[0031] In some embodiments, the mass fraction of lime can be 1 part, 2 parts, 5 parts, 7 parts, 8 parts, 10 parts, 12 parts, and 15 parts, etc.

[0032] In some embodiments, the mass fraction of plant seeds may be 0.1 parts, 0.3 parts, 0.5 parts, 0.7 parts, 0.8 parts, and 1 part, etc.

[0033] In some embodiments, the method for preparing the sludge hydrothermal carbonization slurry includes the following steps: The sludge undergoes a hydrothermal carbonization reaction in an acidic catalyst system to obtain a hydrothermal carbonization slurry.

[0034] In some embodiments, the sludge has a moisture content of 75% to 90%. As an example, the moisture content of the sludge can be 75%, 78%, 80%, 85%, 88%, and 90%, etc.

[0035] In some embodiments, the organic matter content in the sludge is 30% to 80%. As an example, the organic matter content in the sludge can be 30%, 40%, 50%, 60%, 70%, and 80%, etc.

[0036] In some embodiments, the acidic catalyst comprises a citric acid solution.

[0037] In some embodiments, the ratio of the sludge to the citric acid solution is 100g:(10~15)mL.

[0038] In some embodiments, the concentration of the citric acid solution is 20wt% to 30wt%.

[0039] In some embodiments, the temperature of the hydrothermal carbonization reaction is 160~220℃, the time of the hydrothermal carbonization reaction is 2~6h, and the pressure of the hydrothermal carbonization reaction is 1~3MPa. As examples, the temperature of the hydrothermal carbonization reaction can be 160℃, 180℃, 190℃, 200℃, 210℃, and 220℃, etc.; the time of the hydrothermal carbonization reaction can be 2h, 2.5h, 3h, 3.5h, 4h, 5h, and 6h, etc.; and the pressure of the hydrothermal carbonization reaction can be 1MPa, 1.5MPa, 2MPa, 2.5MPa, and 3MPa, etc.

[0040] As an example, the preparation method of sludge hydrothermal carbonization slurry specifically includes: Mix 100g of sludge with a moisture content of 75%~90% and an organic matter content of 30%~80% with 10~15mL of citric acid solution with a concentration of 20~30wt%, and carry out hydrothermal carbonization reaction in a sealed container at 160~220℃ and 1~3MPa for 2~6h.

[0041] In some embodiments, the plant fiber includes crop straw and / or aquatic plants.

[0042] In some embodiments, the particle size of the plant fiber is 0.1~10 mm.

[0043] In some embodiments, the particle size of the soil is 0.1 to 10 mm.

[0044] In some embodiments, the water-retaining agent includes acrylamide-acrylate copolymer crosslinkers and / or starch-grafted acrylate copolymer crosslinkers.

[0045] In some embodiments, the plant seeds include herbaceous plant seeds.

[0046] In some embodiments, the cement comprises PO42.5 cement.

[0047] In some embodiments, it also includes 5 parts of phosphate rock powder.

[0048] A second aspect of the present invention also provides a method for preparing the above-mentioned sludge hydrothermal carbonization slurry ecological remediation bed, comprising the following steps: Mix sludge hydrothermal carbonization slurry, plant fiber, soil, water-retaining agent, cement, lime and plant seeds.

[0049] In some embodiments, the aforementioned preparation method further includes adding phosphate rock powder.

[0050] A third aspect of the present invention also provides an application of the above-mentioned sludge hydrothermal carbonization slurry ecological restoration bed in ecological restoration.

[0051] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. The embodiments of this application are only examples, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] The acrylamide-potassium acrylate copolymer water-retaining agent described below was purchased from Henan Xinliyuan Agricultural Technology Co., Ltd., and the model is high water absorption type (water absorption ratio greater than 300 times). The potting soil was purchased from Shijiazhuang Wofuwo Fertilizer Co., Ltd., and the bio-organic fertilizer is rich in nitrogen, phosphorus, and potassium. The compound fertilizer was purchased from Hefei Shunzhiyuan Chemical Co., Ltd. as potassium dihydrogen phosphate and potassium phosphate compound fertilizer.

[0053] Example 1 (Standardized Ratio) Take 100 parts of sludge hydrothermal carbonization slurry, add 8 parts of corn straw fiber (particle size 1-3mm), 30 parts of local basic soil (passed through a 5mm sieve), 0.05 parts of acrylamide-potassium acrylate copolymer water-retaining agent, 5 parts of PO42.5 cement, 5 parts of lime, and 0.5 parts of plant seeds (tall fescue seeds: Kentucky bluegrass seeds: Bermuda grass seeds = 4:3:3), and mix evenly using a forced mixer to obtain a sludge hydrothermal carbonization slurry ecological restoration bed; then, high-pressure spray seeding is applied to a 45° simulated rock slope with a thickness of 5cm. Under natural curing, the surface crust solidifies in 7 days, the vegetation coverage exceeds 85% in 21 days, and the coverage reaches over 95% after 60 days, with no peeling or erosion of the restoration layer.

[0054] The preparation of the hydrothermal carbonization slurry of sludge involves the following steps: 100g of municipal sludge with a water content of 80% and an organic matter content of 45% and 10mL of citric acid solution with a mass concentration of 20% are subjected to a hydrothermal carbonization reaction at 200℃ and 2MPa for 4h.

[0055] Example 2 (High-strength formula) The difference from Example 1 is that the plant fiber content is 5 parts, the cement content is 8 parts, the lime content is 8 parts, and the remaining components remain unchanged. This mix proportion significantly improves the early (7-day) compressive strength and is suitable for steep slopes with a high risk of erosion or requiring rapid consolidation.

[0056] Example 3 (High water retention ratio) The difference from Example 1 is that the plant fiber content is 10 parts, the base soil content is 40 parts, the cement content is 3 parts, the lime content is 3 parts, and the remaining components remain unchanged. This formulation has better water retention and air permeability, resulting in more outstanding vegetation restoration under arid and low-rainfall conditions.

[0057] Example 4 (Low Cement Ratio) The difference from Example 1 is that the cement content is 2 parts, the lime content is 8 parts, and the remaining components remain the same. This formula has a slightly slower curing speed, but better strength development in the later stages, and the alkalinity is more conducive to neutralizing acidic matrices.

[0058] Example 5 (High Soil Additive Ratio) The difference from Example 1 is that the base soil is 50 parts, plant fiber is 5 parts, and the remaining components remain the same. This formulation is suitable for scenarios requiring a thick remediation layer or where local soil resources are abundant, further reducing costs.

[0059] Example 6 (Improved formulation for acidic tailings) The difference from Example 1 is that the sludge hydrothermal carbonization slurry consists of 100 parts, plant fiber 8 parts, local base soil 30 parts, water-retaining agent 0.05 parts, cement 5 parts, lime 15 parts, with an additional 5 parts phosphate rock powder and 0.5 parts plant seeds. Under this formulation, the substrate pH is effectively raised to the neutral range after hydroseeding, and vegetation successfully establishes itself.

[0060] Example 7 (Formulation for sandy slopes) The difference from Example 1 is that the sludge hydrothermal carbonization slurry contains 100 parts, plant fiber 12 parts, base soil 20 parts, water-retaining agent 0.1 parts, cement 4 parts, lime 4 parts, and plant seeds 0.5 parts. The synergistic effect of fiber and water-retaining agent greatly improves the water and fertilizer retention capacity of sandy land.

[0061] Comparative Example 1 (Traditional hydroseeding technology) A commercially available hydroseeding formula was used: 80 parts purchased nutrient soil, 2 parts compound fertilizer, 10 parts wood fiber binder, 0.1 parts water-retaining agent, and 0.5 parts plant seeds. The same method was applied to the same slope. Initial germination was acceptable, but after continuous rainfall, significant surface erosion and gully erosion occurred. After 60 days, the vegetation coverage was approximately 75%, and the growth was uneven.

[0062] Comparative Example 2 (Sludge-free hydrothermal carbonization slurry control) The mixture consists of 100 parts local base soil, 8 parts plant fiber, 5 parts cement, 5 parts lime, 0.05 parts water-retaining agent, and 0.5 parts plant seeds. Under this ratio, the mixture has poor adhesion and is difficult to attach effectively to the slope. After spraying, it falls off over a large area, and vegetation can hardly grow.

[0063] Comparative Example 3 (Cement-free lime hardener control) The difference from Example 1 is that no cement or lime was added. With this modified mix proportion, the mixture cannot solidify and forms a slurry that flows down the slope, making it completely unfeasible for slope repair.

[0064] Performance testing High-pressure spraying was applied to a 45° simulated rock slope with a thickness of 5 cm, as shown in the examples and comparative examples. The slope was then naturally cured, and performance tests were conducted. The test results are shown in Table 1.

[0065] Table 1

[0066] As demonstrated by the above embodiments and comparative examples, this invention uses sludge hydrothermal carbonization slurry as its core, and through scientific compounding with plant fibers, inorganic cementing materials (cement, lime), etc., successfully constructs an ecological restoration bed that combines engineering stability (erosion resistance, compressive strength), ecological suitability (water retention, fertilizer retention, and growth promotion), and ease of construction. Its performance is comprehensively superior to traditional topsoil spraying technology (Comparative Example 1). Sludge hydrothermal carbonization slurry, as a functional binder and nutrient matrix (Comparative Example 2), and cement and lime, as structural solidifying agents (Comparative Example 3), are both indispensable key components for the success of this technology. Each embodiment demonstrates that by adjusting the proportions, it can flexibly adapt to different geological and climatic conditions, verifying the wide applicability and significant technical advantages of this invention.

[0067] Although preferred embodiments of the invention have been shown and described, it is conceivable that those skilled in the art can devise various modifications to the invention within the spirit and scope of the appended claims.

Claims

1. A sludge hydrothermal carbonization slurry ecological remediation bed, characterized in that, The components include the following parts by mass: The ingredients are: 100 parts of hydrothermal carbonization slurry of sludge, 5-12 parts of plant fiber, 10-50 parts of soil, 0.01-0.1 parts of water-retaining agent, 1-10 parts of cement, 1-15 parts of lime, and 0.1-1 parts of plant seeds.

2. The sludge hydrothermal carbonization slurry ecological restoration bed according to claim 1, characterized in that, The method for preparing the hydrothermal carbonization slurry of the sludge includes the following steps: The sludge undergoes a hydrothermal carbonization reaction under an acidic catalyst system to obtain a hydrothermal carbonization slurry. The sludge has a moisture content of 75% to 90%. The organic matter content in the sludge is 30% to 80%; The acidic catalyst includes a citric acid solution; The temperature of the hydrothermal carbonization reaction is 160~220℃, the time of the hydrothermal carbonization reaction is 2~6h, and the pressure of the hydrothermal carbonization reaction is 1~3MPa.

3. The sludge hydrothermal carbonization slurry ecological restoration bed according to claim 1, characterized in that, The plant fibers include crop straw and / or aquatic plants; The particle size of the plant fiber is 0.1~10mm.

4. The sludge hydrothermal carbonization slurry ecological restoration bed according to claim 1, characterized in that, The soil has a particle size of 0.1~10mm.

5. The sludge hydrothermal carbonization slurry ecological restoration bed according to claim 1, characterized in that, The water-retaining agent includes acrylamide-acrylate copolymer crosslinking and / or starch-grafted acrylate copolymer crosslinking.

6. The sludge hydrothermal carbonization slurry ecological restoration bed according to claim 1, characterized in that, The plant seeds include herbaceous plant seeds; The cement includes PO42.5 cement.

7. The sludge hydrothermal carbonization slurry ecological restoration bed according to claim 1, characterized in that, It also includes 1 to 5 parts of phosphate rock powder.

8. A method for preparing a sludge hydrothermal carbonization slurry ecological restoration bed according to any one of claims 1 to 7, characterized in that, Includes the following steps: Mix sludge hydrothermal carbonization slurry, plant fiber, soil, water-retaining agent, cement, lime and plant seeds.

9. The method for preparing the sludge hydrothermal carbonization slurry ecological restoration bed according to claim 8, characterized in that, It also includes the addition of phosphate rock powder.

10. The application of the sludge hydrothermal carbonization slurry ecological restoration bed according to any one of claims 1 to 7 in ecological restoration.

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