High-value utilization and synergistic carbon sequestration method for household garbage incineration slag

Abstract

The invention relates to the technical field of resource recycling, in particular to a high-value utilization and synergistic carbon sequestration method of household garbage incineration slag, and the high-value utilization method comprises the step of applying the household garbage incineration slag to a soil conditioner. The soil conditioner is prepared from the following raw materials in parts by mass: 20 to 30 parts of household garbage incineration slag, 15 to 25 parts of carbonized straws, 25 to 30 parts of decomposed organic fertilizer, 5 to 8 parts of bentonite, 2 to 3 parts of humate and 0.1 to 0.5 part of microbial compound inoculant. The household garbage incineration slag is applied to the raw materials of the soil conditioner and compounded with other raw materials, so that a remarkable synergistic effect is generated, the aims of treating soil with waste and fixing carbon and reducing emission are achieved, the occupation pressure of slag landfill on land resources is effectively relieved, and secondary resource utilization of waste is promoted.

Description

Technical Field

[0001] This invention relates to the field of resource recycling technology, and in particular to a method for high-value utilization and synergistic carbon sequestration of municipal solid waste incinerator slag. Background Technology

[0002] Municipal solid waste incineration ash is a byproduct of municipal solid waste incineration, including residual ash on the grate and particulate matter falling from between the grates. It has a rough surface and high porosity. After processing, its main components include silicon, calcium, aluminum, potassium, and other substances. Its chemical composition is relatively stable, and these components are all beneficial minerals needed by the soil, providing a material basis for its resource utilization.

[0003] Currently, the main methods for disposing of municipal solid waste incineration ash, both domestically and internationally, are landfilling and stockpiling. Only a small amount of ash is used in low-value-added applications such as road base backfilling. However, the large-scale landfilling and stockpiling of ash not only occupies valuable land resources but also wastes the beneficial mineral resources contained in the ash, preventing its high-value utilization and contradicting the principles of resource-based and harmless environmental governance.

[0004] If municipal solid waste incineration slag is used in the preparation of soil conditioners, its own beneficial mineral components can be fully utilized. This can not only effectively alleviate the pressure on land resources caused by slag landfill and realize the secondary resource utilization of waste, but also specifically improve prominent problems such as soil compaction, poor aeration, and insufficient fertility, achieving the dual benefits of "treating waste with waste and recycling resources". Summary of the Invention

[0005] The purpose of this invention is to provide a method for high-value utilization and synergistic carbon sequestration of municipal solid waste incinerator slag, which solves problems such as soil compaction, poor aeration, and insufficient fertility, while also achieving the goal of secondary utilization of municipal solid waste incinerator slag.

[0006] To achieve the above objectives, the present invention provides a method for high-value utilization of municipal solid waste incinerator slag, wherein the high-value utilization method includes applying municipal solid waste incinerator slag to a soil conditioner; The soil conditioner comprises the following raw materials in parts by weight: 20-30 parts of municipal solid waste incinerator slag, 15-25 parts of carbonized straw, 25-30 parts of well-rotted organic fertilizer, 5-8 parts of bentonite, 2-3 parts of humate, and 0.1-0.5 parts of microbial compound agent.

[0007] In this invention, the soil conditioner preferably comprises the following raw materials in parts by weight: 22-28 parts of municipal solid waste incinerator slag, 18-22 parts of carbonized straw, 26-29 parts of well-rotted organic fertilizer, 6-7 parts of bentonite, 2.5 parts of humate, and 0.2-0.4 parts of microbial compound inoculant.

[0008] In this invention, the composition of the municipal solid waste incineration slag, by mass percentage, includes 20%-45% silicon dioxide, 10%-30% calcium oxide, 5%-15% aluminum oxide, 1%-8% sodium chloride, 1%-5% potassium oxide, 1%-2% magnesium oxide, 0.5%-2% phosphorus oxides, and 0.3%-1.5% sulfur oxides; the phosphorus oxides and sulfur oxides are unavoidable impurities; the particle size of the municipal solid waste incineration slag is preferably 2-5 mm.

[0009] In this invention, the leaching amount of hazardous substances (aluminum, nickel, cadmium, chromium, arsenic, mercury, and cyanide) in the municipal solid waste incineration slag meets the safe concentration limit standard value of GB5085.3-2007 "Identification Standard for Hazardous Waste - Leaching Toxicity Identification"; and the dioxin content meets the requirements of GB16889-2008 "Pollution Control Standard for Municipal Solid Waste Landfills".

[0010] In this invention, the carbonized straw preferably includes at least one of rice straw, wheat straw, and corn straw.

[0011] In this invention, the method for preparing the carbonized straw includes: pyrolyzing the straw at a temperature of 400-600℃ for 1-2 hours to obtain the carbonized straw.

[0012] In this invention, the decomposed organic fertilizer preferably includes at least one of decomposed chicken manure, decomposed cow manure, and decomposed sheep manure.

[0013] In this invention, the composting method of the organic fertilizer can be any method known to those skilled in the art, and is not limited thereto.

[0014] In this invention, the bentonite is preferably sodium-based bentonite, and the sodium-based bentonite preferably contains 85%-90% montmorillonite.

[0015] In this invention, the humate salt includes potassium humate and sodium humate; the mass ratio of potassium humate to sodium humate is preferably 1:0.5-2, more preferably 1:0.8-1.5, and even more preferably 1:1.

[0016] In this invention, the microbial compound inoculant includes Bacillus subtilis, Trichoderma, and yeast; the mass ratio of Bacillus subtilis, Trichoderma, and yeast is preferably 3-5:2-3:1, more preferably 4:2.5:1.

[0017] In this invention, the viable count of the Bacillus subtilis is ≥2.0 × 10⁻⁶. 9 CFU / g, the viable count of the *Trichoderma* species is ≥1.0 × 10⁻⁶. 9 CFU / g, the viable count of the yeast is ≥1.0×10⁻⁶. 9 CFU / g.

[0018] This invention also provides a method for soil carbon sequestration, wherein the raw materials of the soil conditioner used in the high-value utilization method of municipal solid waste incineration slag described in the above technical solution are mixed according to the mass fraction, granulated, and the soil conditioner is obtained; the soil conditioner is applied to the top 10-20cm of soil at a dosage of 300-800 kg per acre.

[0019] The present invention has the following beneficial effects: This invention provides a method for the high-value utilization of municipal solid waste incineration slag. The method includes applying the municipal solid waste incineration slag to a soil conditioner. The soil conditioner comprises the following raw materials in parts by weight: 20-30 parts of municipal solid waste incineration slag, 15-25 parts of carbonized straw, 25-30 parts of well-rotted organic fertilizer, 5-8 parts of bentonite, 2-3 parts of humate, and 0.1-0.5 parts of microbial compound inoculant.

[0020] This invention applies municipal solid waste incinerator slag to the raw materials of soil conditioners. When combined with other raw materials, it produces a significant synergistic effect, which not only achieves the goal of "treating soil with waste and reducing carbon emissions", but also effectively alleviates the pressure on land resources caused by slag landfill and promotes the secondary resource utilization of waste.

[0021] The soil conditioner provided by this invention utilizes the combined action of municipal solid waste incineration slag and carbonized straw to significantly increase the total porosity of the soil, effectively improving soil compaction and creating a loose and breathable growing environment for plant roots. Simultaneously, the combined action of these two components with bentonite and well-rotted organic fertilizer helps form a water-stable aggregate structure, not only enhancing the soil's resistance to rainfall erosion and reducing the loss of soil carbon and nutrients, but also achieving a good balance between soil aeration, water retention, and fertilizer retention.

[0022] Well-rotted organic fertilizer provides the soil with readily available nitrogen, phosphorus, potassium, amino acids, sugars, and other nutrients, while also serving as an important energy source for microbial activity. Humic acid salts and bentonite, through adsorption and exchange, continuously retain and slowly release nutrients, effectively preventing the leaching of nutrient ions such as ammonium and potassium. Microbial compound inoculants further activate the existing potential fertility of phosphorus and potassium in the soil. The synergistic effect of these three elements jointly constructs a soil fertility enhancement system.

[0023] Municipal solid waste incineration ash is rich in calcium oxide, which can gently and persistently neutralize acidic soil and provide calcium nutrition, further promoting the formation of soil aggregates. Carbonized straw introduces a highly stable aromatic carbon structure into the soil, and its anti-decomposition properties enable long-term carbon sequestration, playing an important role in carbon fixation.

[0024] The present invention further specifies that the bentonite is sodium-based bentonite, wherein the sodium-based bentonite contains 85%-90% montmorillonite. Sodium-based bentonite has extremely strong water absorption and swelling properties and cation exchange capacity, which improves the water holding capacity of the soil and prevents the leaching of nutrients such as ammonium and potassium in the soil. At the same time, it improves the soil pore distribution and enhances the stability of the structure.

[0025] The present invention further specifies that humates include potassium humate and sodium humate, which can activate plant root development and enzyme activity in the soil and enhance stress resistance.

[0026] This invention further specifies that the microbial compound inoculant includes Bacillus subtilis, Trichoderma, and yeast. Bacillus subtilis can secrete secondary metabolites such as antimicrobial peptides, effectively inhibiting soil-borne pathogens and accelerating the decomposition of organic matter by producing proteases and cellulases. Trichoderma can prevent and control plant root diseases while efficiently degrading lignocellulose and other difficult-to-decompose organic matter. Yeast creates a microenvironment conducive to the growth of beneficial microorganisms through rapid fermentation and secretes plant growth stimulants such as vitamins and amino acids. The three work synergistically to construct a highly efficient soil biological activation system, significantly accelerating the humification process of organic fertilizers.

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a comparison chart of rice yield in an application example of the present invention. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0030] In the following embodiments of the present invention, the leaching amount of hazardous substances (aluminum, nickel, cadmium, chromium, arsenic, mercury, and cyanide) in the municipal solid waste incineration slag meets the safe concentration limit standard value of GB5085.3-2007 "Identification Standard for Hazardous Waste without Toxicity Identification"; the dioxin content meets the requirements of GB16889-2008 "Pollution Control Standard for Municipal Solid Waste Landfills", and the particle size range is 2-5mm.

[0031] The bentonite used in the following embodiments of the present invention is sodium-based bentonite with a montmorillonite content of 85%-90%.

[0032] In the following embodiments of the present invention, the viable count of Bacillus subtilis is ≥2.0 × 10⁻⁶. 9 CFU / g, viable count of Trichoderma ≥1.0×10⁻⁶ 9 CFU / g, viable yeast count ≥1.0×10⁻⁶ 9 CFU / g.

[0033] Example 1 This embodiment provides a soil conditioner, which is composed of the following raw materials in parts by weight: 20 portions of municipal solid waste incinerator slag, 22 portions of carbonized corn stalks, 25 portions of decomposed chicken manure, 8 portions of sodium bentonite, 2 portions of humate, and 0.5 portions of microbial compound inoculant.

[0034] The humate contains 1 part potassium humate and 1 part sodium humate.

[0035] The microbial compound inoculant contained 0.25 parts of Bacillus subtilis, 0.1875 parts of Trichoderma, and 0.0625 parts of yeast.

[0036] The corn stalks that have undergone the above carbonization process are obtained by pyrolyzing corn stalks at 400℃ for 1 hour.

[0037] Example 2 This embodiment provides a soil conditioner, which is composed of the following raw materials in parts by weight: 28 portions of municipal solid waste incinerator slag, 25 portions of carbonized wheat straw, 26 portions of decomposed cow manure, 7 portions of sodium bentonite, 2.5 portions of humate, and 0.4 portions of microbial compound inoculant.

[0038] The humate contains 1 part potassium humate and 1.5 parts sodium humate.

[0039] The microbial compound inoculant contains 0.2 parts of Bacillus subtilis, 0.15 parts of Trichoderma, and 0.05 parts of yeast.

[0040] The above-mentioned carbonized wheat straw is obtained by pyrolyzing wheat straw at 600℃ for 1 hour.

[0041] Example 3 This embodiment provides a soil conditioner, which is composed of the following raw materials in parts by weight: 22 portions of municipal solid waste incinerator slag, 15 portions of carbonized wheat straw, 29 portions of decomposed sheep manure, 8 portions of sodium bentonite, 3 portions of humate, and 0.5 portions of microbial compound inoculant.

[0042] The humate contains 2 parts potassium humate and 1 part sodium humate.

[0043] The microbial compound inoculant contained 0.25 parts of Bacillus subtilis, 0.1875 parts of Trichoderma, and 0.0625 parts of yeast.

[0044] The above-mentioned carbonized wheat straw is obtained by pyrolyzing wheat straw at 600℃ for 1 hour.

[0045] Example 4 This embodiment provides a soil conditioner, which is composed of the following raw materials in parts by weight: 30 parts of municipal solid waste incinerator slag, 18-22 parts of carbonized rice straw, 30 parts of well-rotted cow manure, 7 parts of sodium bentonite, 2.5 parts of humate, and 0.2 parts of microbial compound agent.

[0046] The humate contains 1 part potassium humate and 1.5 parts sodium humate.

[0047] The microbial compound inoculant contains 0.2 parts of Bacillus subtilis, 0.075 parts of Trichoderma, and 0.025 parts of yeast.

[0048] The rice straw that has undergone the above carbonization process is obtained by pyrolyzing rice straw at 500°C for 2 hours.

[0049] Example 5 This embodiment provides a soil conditioner, which is composed of the following raw materials in parts by weight: 25 portions of municipal solid waste incinerator slag, 20 portions of carbonized corn stalks, 28 portions of decomposed chicken manure, 7 portions of sodium bentonite, 3 portions of humate, and 0.2 portions of microbial compound inoculant.

[0050] The humate contains 1 part potassium humate and 2 parts sodium humate.

[0051] The microbial compound inoculant contains 0.05 parts of Bacillus subtilis, 0.0375 parts of Trichoderma, and 0.0125 parts of yeast.

[0052] The corn stalks that have undergone the above carbonization process are obtained by pyrolyzing corn stalks at 400℃ for 1 hour.

[0053] Comparative Example 1 This comparative example provides a soil conditioner with essentially the same raw material composition as the soil conditioner provided in Example 1, the only difference being that it does not include carbonized corn stalks.

[0054] Comparative Example 2 This comparative example provides a soil conditioner with essentially the same raw material composition as the soil conditioner provided in Example 1, the only difference being that it does not include humic acid salts.

[0055] Comparative Example 3 This comparative example provides a soil conditioner with essentially the same raw material composition as the soil conditioner provided in Example 1, the only difference being that it does not include microbial compound inoculants.

[0056] Application examples The raw materials provided in Examples 1-5 and Comparative Examples 1-3 were mixed in proportion, granulated, and the corresponding soil conditioners were obtained. Field trials were then conducted on rice plants, and these were designated as experimental groups. A control group was also designed; no soil conditioner was applied to the control group, and no rice was planted. Only physicochemical properties were tested. A total of nine experimental plots were used, each covering an area of ​​30 m². 2 In the experimental group, the soil conditioner obtained above was applied to the top 20cm of soil at a rate of 400 kg per mu. The soil quality changes were characterized by measuring the soil physicochemical properties and rice yield. Five measurement points were randomly selected in each field experiment, and the average value was taken to determine the improvement effect of different soil conditioners on paddy field soil quality. The results are shown in Table 1.

[0057] See the comparison chart of rice yield. Figure 1 ,from Figure 1 As can be clearly seen, this invention applies municipal solid waste incineration slag to soil conditioners, and when used in combination with other raw materials, it significantly increases rice yield.

[0058] Table 1. Effects of soil quality improvement in paddy fields

[0059] As shown in Table 1, by compounding municipal solid waste incinerator slag with other raw materials, the total porosity of the soil treated in each embodiment increased by 92.8%-101.6%, the cation exchange capacity increased by 101.6%-114.2%, and the soil pH value was adjusted from acidic (5.1) to a slightly acidic to neutral range (6.6-6.9) suitable for crop growth, thus optimizing the physical and chemical properties of the soil.

[0060] In Comparative Example 1, without the addition of carbonized straw, the total soil porosity decreased by 34.0% compared to Example 1, the cation exchange capacity decreased by 28.5%, the pH value dropped back to slightly acidic, and the rice yield decreased by 31.7%. This demonstrates that carbonized straw is a core component for improving soil porosity, regulating pH, and enhancing cation exchange capacity, and is also key to ensuring the crop growth environment.

[0061] In Comparative Example 2, the cation exchange capacity decreased by 18.7% and the rice yield decreased by 14.3% in the experimental field without the addition of humic acid salts compared to Example 1, demonstrating that humic acid salts play an irreplaceable role in improving soil fertility (cation exchange capacity) and activating soil nutrients.

[0062] In Comparative Example 3, without the addition of microbial compound inoculant, the rice yield decreased by 10.4% compared to Example 1, and the total soil porosity and cation exchange capacity also decreased to varying degrees. This demonstrates that the microbial compound inoculant can effectively activate soil nutrients and promote the decomposition of organic matter, and is an important component for achieving increased crop yield and optimization of the soil microenvironment.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for high-value utilization of municipal solid waste incinerator slag, characterized in that, The high-value utilization method includes applying municipal solid waste incineration slag to soil conditioners; The soil conditioner comprises the following raw materials in parts by weight: 20-30 parts of municipal solid waste incinerator slag, 15-25 parts of carbonized straw, 25-30 parts of well-rotted organic fertilizer, 5-8 parts of bentonite, 2-3 parts of humate, and 0.1-0.5 parts of microbial compound agent.

2. The method for high-value utilization of municipal solid waste incinerator slag according to claim 1, characterized in that, The composition of the municipal solid waste incineration slag, by mass percentage, includes 20%-45% silicon dioxide, 10%-30% calcium oxide, 5%-15% aluminum oxide, 1%-8% sodium chloride, 1%-5% potassium oxide, 1%-2% magnesium oxide, 0.5%-2% phosphorus oxides, and 0.3%-1.5% sulfur oxides. The particle size of the municipal solid waste incineration slag is 2-5mm.

3. A method for high-value utilization of municipal solid waste incinerator slag according to claim 1, characterized in that, The carbonized straw includes at least one of rice straw, wheat straw, and corn straw.

4. A method for high-value utilization of municipal solid waste incinerator slag according to claim 1 or 3, characterized in that, The method for preparing the carbonized straw includes: The straw is pyrolyzed at 400-600℃ for 1-2 hours to obtain carbonized straw.

5. A method for high-value utilization of municipal solid waste incinerator slag according to claim 1, characterized in that, The decomposed organic fertilizer includes at least one of decomposed chicken manure, decomposed cow manure, and decomposed sheep manure.

6. A method for high-value utilization of municipal solid waste incinerator slag according to claim 1, characterized in that, The bentonite is sodium-based bentonite, and the sodium-based bentonite contains 85%-90% montmorillonite.

7. A method for high-value utilization of municipal solid waste incinerator slag according to claim 1, characterized in that, The humate salt includes potassium humate and sodium humate; the mass ratio of potassium humate to sodium humate is 1:0.5-2.

8. A method for high-value utilization of municipal solid waste incinerator slag according to claim 1, characterized in that, The microbial compound inoculant includes Bacillus subtilis, Trichoderma, and yeast; The mass ratio of Bacillus subtilis, Trichoderma, and yeast is 3-5:2-3:

1.

9. A method for high-value utilization of municipal solid waste incinerator slag according to claim 8, characterized in that, The viable count of the Bacillus subtilis is ≥2.0 × 10⁻⁶. 9 CFU / g, the viable count of the *Trichoderma* species is ≥1.0 × 10⁻⁶. 9 CFU / g, the viable count of the yeast is ≥1.0×10⁻⁶. 9 CFU / g.

10. A method for soil carbon sequestration, characterized in that, The soil conditioner raw materials used in the high-value utilization method of municipal solid waste incineration slag according to any one of claims 1-9 are mixed according to mass parts and then granulated to obtain the soil conditioner. Apply the soil conditioner at a rate of 300-800 kg per acre to the top 10-20 cm of soil.

Images