A method for composting fermentation by using earthworms and compound microbial agent, compost and application

Abstract

This invention provides a method for composting fermentation using earthworms and a compound microbial agent, as well as the compost and its application. The method includes inoculating earthworms and the compound microbial agent into a solid waste substrate for fermentation to obtain compost. The solid waste substrate includes coal gangue, sludge, and organic matter. The compound microbial agent includes non-decarboxylated Leclercella bacteria and frost-resistant short bacilli, as well as biochar loaded with these bacteria. The non-decarboxylated Leclercella bacteria are classified and named as *Leclercella non-decarboxylated Leclercella*. Leclercia adecarboxylata The preservation number is CGMCC No.36871; the preservation number of the cold-resistant short bacillus is SHBCC D71512; the organic matter includes straw; the fermentation temperature is ≤35℃; the composting fermentation method of the present invention can optimize the carbon and nitrogen conversion rate of coal gangue sludge multi-source solid waste matrix, and improve the passivation rate of active heavy metals and the seed germination index in the solid waste matrix.

Description

Technical Field

[0001] This invention relates to the field of composting fermentation technology, specifically to a method for composting fermentation using earthworms and compound microbial agents, as well as the prepared compost and its application. Background Technology

[0002] During coal mining, approximately one-third of the coal mined is gangue. The washing and processing of gangue also results in large amounts of gangue occupying land. This not only wastes land resources but also, due to its complex composition and heavy metal content, easily causes environmental pollution if left untreated. Currently, there are various ways to dispose of gangue, including landfilling, mine backfilling, building material production, and energy conversion. However, because gangue itself is highly alkaline, even after combined physical and chemical treatments, its alkalinity remains and may even increase. Adding it to soil significantly raises the pH value, leading to soil salinization, which is detrimental to the growth of many plants. Some scholars have also studied the effectiveness of gangue as artificial soil, finding that it contains relatively little organic matter and has uneven mineral nutrient content, failing to meet the growth needs of most plants.

[0003] Domestic and international scholars have studied the preparation of artificial soil by mixing sludge and gangue. Although the combination can improve the organic matter content and soil structure of artificial soil to some extent, it cannot effectively control the combined toxicity of heavy metals (such as Cd and Pb) and secondary pollutants from sludge in the gangue-sludge mixture, resulting in a low germination index (<50%). Moreover, when artificial soil prepared by mixing gangue and sludge is composted with microorganisms, technical bottlenecks such as low carbon-nitrogen conversion rate (C / N ratio decrease <30%) and long humus synthesis cycle (60 days) have been found. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a method for composting fermentation using earthworms and compound microbial agents, as well as the compost prepared and its application. The composting fermentation method of the present invention can optimize the carbon and nitrogen conversion rate of coal gangue sludge multi-source solid waste matrix, and improve the passivation rate of active heavy metals and seed germination index in solid waste matrix.

[0005] The inventors of this invention have discovered through research that by preparing a solid waste matrix from coal gangue, sludge, and straw, and then inoculating it with a compound bacterial agent consisting of non-decarboxylated Leclercella bacteria (CGMCC No. 36871) and cold-resistant short bacilli (SHBCCD71512) supported by biochar and earthworms for decomposition and fermentation, the carbon and nitrogen conversion rate of the coal gangue and sludge multi-source solid waste matrix can be optimized, and the passivation rate of active heavy metals and the seed germination index in the solid waste matrix can be improved. Analysis suggests that, on the one hand, the combined effect of microbial agents and earthworms synergistically enhances the composting fermentation: the presence of the microbial agents promotes the digestion of composting materials by earthworms and facilitates the conversion of oxidizable heavy metals, especially mercury, in the composting system, accumulating them in the earthworms in weakly acidic and oxidizable forms. During these biological activities, the earthworms help create a suitable carbon-nitrogen ratio for microbial fermentation and a stable, suitable water, air, and weakly acidic environment in the composting system. This, in turn, promotes the proliferation of the microbial agents and the efficiency of humic synthesis from the solid waste substrate. Furthermore, it further promotes the proliferation and biological activity of native proteinophilic bacteria and Bacillus subtilis in the solid waste substrate, thus synergistically enhancing the composting fermentation effect. On the other hand, the biological activities of microorganisms and earthworms help activate the mineral lattice of coal gangue in the solid waste substrate, activating and releasing beneficial elements such as phosphorus and potassium, increasing the effective nutrient content of the substrate, improving the substrate structure, further enhancing the synergistic composting fermentation effect of the microbial agents and earthworms, and also increasing earthworm yield.

[0006] Based on the above analysis, in a first aspect, the present invention provides a method for composting fermentation using earthworms and compound microbial agents, wherein the composting fermentation method includes inoculating earthworms and compound microbial agents into a solid waste substrate for fermentation to obtain compost; The solid waste substrate includes coal gangue, sludge, and organic matter; The compound microbial agent includes non-decarboxylated Leclercella and cold-resistant short bacilli, as well as biochar loaded with non-decarboxylated Leclercella and cold-resistant short bacilli. The compound microbial agent includes non-decarboxylated Leclercella and cold-resistant short bacilli, as well as biochar loaded with non-decarboxylated Leclercella and cold-resistant short bacilli. The non-decarboxylating Leclercella bacteria are classified and named as non-decarboxylating Leclercella. Leclercia adecarboxylata The accession number is CGMCC No. 36871; The preservation number of the cold-resistant short bacillus is SHBCC D71512; The organic matter includes straw; the fermentation temperature is ≤35℃.

[0007] In a preferred embodiment of the present invention, the mass ratio of coal gangue, sludge and organic matter, on a dry basis, is 1:0.5-2:1-11, preferably 1:0.6-1.2:1.5-5.5, and more preferably 1:0.9-1.1:4-5.

[0008] In a preferred embodiment of the present invention, the moisture content of the solid waste substrate is 45wt%-65wt%, preferably 45wt%-55wt%.

[0009] In a preferred embodiment of the present invention, the carbon-nitrogen ratio of the solid waste matrix is ​​21-27:1 (for example, it can be any value among 21:1, 22:1, 23:1, 24:1, 25:1, 26:1 and 27:1 or any value between any two values).

[0010] In a preferred embodiment of the present invention, the particle size of the coal gangue is ≤5mm, preferably ≤1mm.

[0011] In a preferred embodiment of the present invention, the length of the straw is 3-5 cm.

[0012] In a preferred embodiment of the present invention, the organic matter further includes animal manure. Preferably, on a dry basis, the mass ratio of straw to animal manure is 1:0.8-1.2, more preferably 1:0.9-1.1 (for example, it can be any value or any value between any two of 1:0.9, 1:0.92, 1:0.94, 1:0.96, 1:0.98, 1:1, 1:1.02, 1:1.04, 1:1.06, 1:1.08, and 1:1.1).

[0013] In a preferred embodiment of the present invention, the straw is selected from at least one of corn straw, wheat straw, sugarcane straw and rice straw, preferably corn straw.

[0014] In a preferred embodiment of the present invention, the animal excrement is preferably selected from at least one of sheep excrement, cow excrement, chicken excrement, pig excrement, and pigeon excrement, with cow excrement being the most preferred.

[0015] In a preferred embodiment of the present invention, the sludge is selected from municipal sludge. In the present invention, municipal sludge refers to semi-solid or solid material (excluding screenings, scum, and grit) discharged from primary sedimentation tanks, secondary sedimentation tanks, etc., during the wastewater purification process of urban wastewater treatment plants.

[0016] In a preferred embodiment of the present invention, the biochar is selected from iron-modified gasification slag-based biochar.

[0017] In a preferred embodiment of the present invention, the preparation method of the compound microbial agent includes the following steps: Step S1: After expanding the culture of the non-decarboxylated Leclercella, centrifuge to collect the bacterial cells, and resuspend the bacterial cells in 0.85% saline solution to obtain a non-decarboxylated Leclercella bacterial solution; After the cold-resistant short bacillus was expanded and centrifuged, the bacterial cells were resuspended in 0.85% saline solution to obtain the cold-resistant short bacillus bacterial solution. Step S2: Mix the gasification slag and straw residue evenly, and then impregnate them in ferrous oxalate solution for modification; take out the impregnated mixture and dry it, and then carry out the first pyrolysis and second pyrolysis treatment in an inert atmosphere to obtain iron-modified gasification slag-based biochar. Step S3: Mix the non-decarboxylated Leclercella bacterial solution and the frost-resistant Short Bacillus bacterial solution with iron-modified gasification slag-based biochar to obtain a mixed liquid. Then, place the mixed liquid in a shaker for adsorption treatment. After the adsorption treatment is completed, centrifuge to obtain a composite bacterial agent containing non-decarboxylated Leclercella and frost-resistant Short Bacillus, as well as iron-modified gasification slag-based biochar loaded with non-decarboxylated Leclercella and frost-resistant Short Bacillus. Analysis suggests that, on the one hand, the iron-modified gasification slag-based biochar prepared using this optimized method adsorbs and loads non-decarboxylated Leclercella and frost-resistant Short Bacillus, which is more conducive to the uniformity and stability of their distribution, further synergistically improving the fermentation effect on solid waste substrates. On the other hand, the iron-modified gasification slag-based biochar carries abundant Fe-OH and Fe-O bonds; the better uniformity and stability of the non-decarboxylated Leclercella and frost-resistant Short Bacillus, along with the abundant Fe-OH and Fe-O bonds, can synergistically enhance the absorption and transformation of heavy metals in compost by earthworms, effectively reducing the heavy metal content in compost. In this field, Fe-OH and Fe-O bonds can be determined using conventional techniques, such as Fourier transform infrared spectroscopy (FTIR).

[0018] In a preferred embodiment of the present invention, in step S1, the absorbance of the non-decarboxylated Leclercella bacterial solution is 1.0-2.0, preferably 1.5-1.6 (for example, it can be any value among 1.5, 1.51, 1.52, 1.53, 1.54, 1.55, 1.56, 1.57, 1.58, 1.59 and 1.6 or any value between any two values).

[0019] In a preferred embodiment of the present invention, in step S1, the absorbance of the cold-resistant short bacillus bacterial solution is 1.0-2.0, preferably 1.5-1.6 (for example, it can be any value among 1.5, 1.51, 1.52, 1.53, 1.54, 1.55, 1.56, 1.57, 1.58, 1.59 and 1.6 or any value between any two values).

[0020] In a preferred embodiment of the present invention, in step S1, the non-decarboxylated Leclercella is propagated using a first liquid culture medium, the formulation of which is: peptone 1-4 g / L, sodium carboxymethyl cellulose 3-10 g / L, potassium dihydrogen phosphate 0.5-2 g / L, magnesium sulfate heptahydrate 0.3-1.0 g / L, sodium chloride 0.3-1.0 g / L, pH 6-9.

[0021] In a preferred embodiment of the present invention, step S1, the method for expanding the non-decarboxylated Leclercella bacteria includes: inoculating the non-decarboxylated Leclercella bacteria into a first liquid culture medium, and then culturing it at 10-20°C for 60-80 hours.

[0022] In a preferred embodiment of the present invention, in step S1, the cold-resistant short bacillus is expanded using a second liquid culture medium, the second liquid culture medium being LB liquid culture medium, and the method for expanding the cold-resistant short bacillus includes: inoculating the cold-resistant short bacillus into LB liquid culture medium, and then culturing it at 25-35°C for 60-80 hours.

[0023] In a preferred embodiment of the present invention, in step S2, the mass ratio of the gasification slag to the straw slag is 1:0.5-2, preferably 1:0.8-1.1.

[0024] In a preferred embodiment of the present invention, in step S2, the particle size of the gasification slag is ≤150μm, preferably ≤74μm.

[0025] In a preferred embodiment of the present invention, in step S2, the particle size of the straw residue is ≤150μm, preferably ≤74μm.

[0026] In a preferred embodiment of the present invention, in step S2, the straw residue is selected from at least one of corn straw residue, wheat straw residue, sugarcane straw residue and rice straw residue, preferably corn straw residue.

[0027] In a preferred embodiment of the present invention, in step S2, the concentration of the ferrous oxalate solution is 0.3-1.0 mol / L (for example, it can be any value among 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L and 1.0 mol / L or any value between any two values).

[0028] In a preferred embodiment of the present invention, in step S2, the conditions for the impregnation modification include: an impregnation temperature of 22-28°C and an impregnation time of 20-30 hours.

[0029] In a preferred embodiment of the present invention, in step S2, the conditions for the first pyrolysis include: a pyrolysis temperature of 400-600℃, preferably 450-550℃; and a pyrolysis time of 0.5-1.5h, preferably 0.8-1.2h.

[0030] In a preferred embodiment of the present invention, step S2 further includes: before the first pyrolysis, heating to the first pyrolysis temperature at a rate of 3-10℃ / min in an inert atmosphere.

[0031] In a preferred embodiment of the present invention, step S2 further includes: before the second pyrolysis, raising the temperature from the first pyrolysis temperature to the second pyrolysis temperature at a rate of 1-5°C / min in an inert atmosphere.

[0032] In a preferred embodiment of the present invention, in step S2, the conditions for the second pyrolysis include: a pyrolysis temperature of 700-900℃, preferably 750-850℃; and a pyrolysis time of 1-3h, preferably 1.5-2.5h.

[0033] In a preferred embodiment of the present invention, in step S2, the inert atmosphere is selected from at least one of nitrogen atmosphere, helium atmosphere, neon atmosphere and argon atmosphere.

[0034] In a preferred embodiment of the present invention, in step S3, the volume ratio of the non-decarboxylated Leclercella bacterial solution and the frost-resistant Short Bacillus bacterial solution is 1:0.8-1.2.

[0035] In a preferred embodiment of the present invention, in step S3, the total amount of the non-decarboxylated Leclercella bacterial solution and the frost-resistant Short Bacillus bacterial solution to the amount of iron-modified gasification slag-based biochar is (40-70) mL:1g, preferably (45-55) mL:1g (for example, it can be any value or any value between any two of 45mL:1g, 46mL:1g, 47mL:1g, 48mL:1g, 49mL:1g, 50mL:1g, 51mL:1g, 52mL:1g, 53mL:1g, 54mL:1g, and 55mL:1g).

[0036] In a preferred embodiment of the present invention, in step S3, the conditions for the adsorption treatment include: an adsorption temperature of 20-35℃, preferably 23-27℃; and an adsorption time of 6-72h, preferably 30-40h.

[0037] In a preferred embodiment of the present invention, in step S3, the rotational speed of the shaking table is 140-200 rpm.

[0038] In a preferred embodiment of the present invention, in step S3, the pH value of the mixed liquid is 7.5-8.5.

[0039] In a preferred embodiment of the present invention, the inoculation amount of the compound microbial agent, based on the mass of water contained in the solid waste substrate, is 0.9-3 g / kg, preferably 0.9-1.3 g / kg (for example, it can be any value or any value between any two of 0.9 g / kg, 0.95 g / kg, 1 g / kg, 1.05 g / kg, 1.1 g / kg, 1.15 g / kg, 1.2 g / kg, 1.25 g / kg and 1.3 g / kg).

[0040] In a preferred embodiment of the present invention, the composting fermentation method further includes: before inoculation, laying the solid waste substrate into a pile, preferably laying it into a strip-shaped pile.

[0041] In a preferred embodiment of the present invention, the height of the pile is 0.2-0.4m.

[0042] In a preferred embodiment of the present invention, relative to 1m 2 The surface area of ​​the strip-shaped pile, and the inoculation amount of the earthworm seedlings is 0.5-1.6 kg, preferably 0.8-1.2 kg (for example, it can be any value or any value between any two of 0.8 kg, 0.85 kg, 0.9 kg, 0.95 kg, 1 kg, 1.05 kg, 1.1 kg, 1.15 kg and 1.2 kg).

[0043] In a preferred embodiment of the present invention, the earthworms are inoculated into a solid waste substrate in the form of earthworm seedlings. The earthworms are selected from at least one of Eisenia fetida, Vertrilia William, Vertrilia Eugene, and Vertrilia burrowing, with Eisenia fetida being the preferred choice.

[0044] In a preferred embodiment of the present invention, the fermentation conditions include: a fermentation temperature ≤35℃, preferably 22-26℃ (for example, any value among 22℃, 23℃, 24℃, 25℃ and 26℃ or any value between any two values), and a fermentation time of 16-24 days, preferably 18-22 days (for example, any value among 18d, 19d, 20d, 21d and 22d or any value between any two values).

[0045] In a preferred embodiment of the present invention, the composting fermentation method further includes: turning the strip-shaped pile during the fermentation process; preferably, the turning frequency is once every 3-5 days; In a preferred embodiment of the present invention, the composting fermentation method further includes: after fermentation is completed, screening and separating earthworms from the compost.

[0046] Secondly, the present invention provides compost prepared by the composting fermentation method described in the first aspect.

[0047] Thirdly, the present invention provides the application of compost prepared by the composting fermentation method described in the first aspect or the compost described in the second aspect in soil improvement.

[0048] The beneficial effects of this invention are at least in the following aspects: Firstly, combining coal gangue, sludge, and organic matter can enhance the synergistic effect of earthworms and compound microbial agents, resulting in a carbon-to-nitrogen ratio (C / N) of 11-16:1 in the compost product. This improves the maturation quality of the solid waste substrate, seed germination index, and plant biomass, while effectively reducing the heavy metal toxicity of the compost (the passivation rate of active arsenic can reach over 6%, and the passivation rate of active mercury can reach over 8%).

[0049] Secondly, the iron-modified gasification slag-based biochar loaded with non-decarboxylated Leclercella and cold-resistant short bacilli not only has strong loading capacity and optimized microbial distribution, improving the metabolic activity of microorganisms and the maturation effect of compound maturation agents during composting, but also synergistically improves the absorption and passivation effect of earthworms on heavy metals Hg and As, reducing the heavy metal ecological risk level of compost products.

[0050] Third, the addition of earthworms can synergistically enhance the key metabolites of microorganisms with the compound microbial agent, further promoting the passivation effect of earthworms on heavy metals Hg and As in the compost substrate.

[0051] Fourth, the combined approach of earthworms and low-temperature bacteria improved the microbial community structure in the compost substrate, increased the relative abundance of proteinophilic bacteria and slaughter bacilli, and increased the expression of key metabolites of microorganisms, further promoting the passivation of heavy metals by earthworms.

[0052] Fifth, it significantly promotes plant height and biomass, with remarkable growth-promoting effects. Attached Figure Description

[0053] Figure 1 This is a bar graph showing the effect of compost products on plant height and biomass as determined in Test Example 3. Detailed Implementation

[0054] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited to the following description.

[0055] Non-decarboxylated Leclercella: Classified as non-decarboxylated Leclercella Leclercia adecarboxylataThe strain was deposited on December 1, 2025, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, with accession number CGMCC No. 36871. The 16S rDNA sequence (SEQ ID NO. 1) of the strain is as follows:

[0056] Cold-resistant short bacilli: classified and named Brevibacterium frigoritolerans, Purchased from Shanghai Biotechnology Center, strain accession number: SHBCC D71512.

[0057] The first liquid culture medium formula is as follows: peptone 4 g / L, sodium carboxymethyl cellulose 5 g / L, potassium dihydrogen phosphate 1 g / L, magnesium sulfate heptahydrate 0.7 g / L, sodium chloride 0.5 g / L, pH 6; Weigh 1g of peptone, 1.25g of sodium carboxymethyl cellulose, 0.25g of potassium dihydrogen phosphate, 0.175g of magnesium sulfate heptahydrate, and 0.125g of sodium chloride. Dissolve the solid powder in 250mL of distilled water, adjust the pH to 6, and sterilize at 120℃ for 120min.

[0058] LB liquid medium formulation: yeast extract 5.0 g / L, peptone 10.0 g / L, NaCl 10.0 g / L, pH 7.0; Weigh 1.25g of yeast extract, 2.5g of peptone, and 2.5g of NaCl solid powder, dissolve them in 250mL of distilled water, adjust the pH to 6, and sterilize at 120℃ for 120min.

[0059] Gasification slag: sourced from coal chemical plants around Baotou City, with a particle size ≤74μm.

[0060] Urban sludge: from Dongsheng Wastewater Treatment Plant in Ordos City, Inner Mongolia Autonomous Region, with a water content of 80 wt%.

[0061] Corn stalks: moisture content 30wt%.

[0062] Cow dung: Moisture content is 38 wt%.

[0063] Example 1 Step S1: Inoculate non-decarboxylated Leclercella into the first liquid culture medium and then incubate at 15°C for 72 h; after the incubation is completed, centrifuge to collect the bacterial cells, and resuspend the bacterial cells with 0.85% saline to obtain a non-decarboxylated Leclercella bacterial suspension with an absorbance of 1.55. The cold-resistant short bacillus was inoculated in LB liquid medium and then cultured at 30°C for 72 h. After the culture was completed, the bacterial cells were centrifuged and resuspended in 0.85% saline to obtain a cold-resistant short bacillus bacterial suspension with an absorbance of 1.55.

[0064] Step S2: Mix the gasification slag and corn straw residue evenly, then impregnate them in a ferrous oxalate solution for modification. Remove the impregnated mixture and dry it. Then, perform a first pyrolysis under a nitrogen atmosphere, raising the temperature to the pyrolysis temperature at a rate of 5℃ / min. After the first pyrolysis, perform a second pyrolysis treatment, raising the temperature from the first pyrolysis temperature to the second pyrolysis temperature at a rate of 3℃ / min, to obtain iron-modified gasification slag-based biochar. The mass ratio of gasification slag to straw residue is 1:1, the particle size of the gasification slag is ≤74μm, the particle size of the corn straw residue is ≤74μm, and the concentration of the ferrous oxalate solution is 0.5 mol·L⁻¹. -1 The impregnation temperature is 25℃, the impregnation time is 24h, the first pyrolysis temperature is 500℃, the first pyrolysis time is 1h, the second pyrolysis temperature is 800℃, and the second pyrolysis time is 2h.

[0065] Step S3: Mix the non-decarboxylated Leclercella bacteria solution and the frost-resistant Short Bacillus bacteria solution with iron-modified gasification slag-based biochar, adjust the pH value to 8, and obtain a mixed solution. Then, place the mixed solution in a shaker for adsorption treatment. After the adsorption treatment is completed, centrifuge to obtain a composite bacterial agent including non-decarboxylated Leclercella bacteria and frost-resistant Short Bacillus, as well as iron-modified gasification slag-based biochar loaded with non-decarboxylated Leclercella bacteria and frost-resistant Short Bacillus. The volume ratio of non-decarboxylated Leclercella bacteria solution to frost-resistant Short Bacillus bacteria solution is 1:1, and the ratio of the total amount of non-decarboxylated Leclercella bacteria solution and frost-resistant Short Bacillus bacteria solution to the amount of iron-modified gasification slag-based biochar is 50 mL: 1 g. The shaking speed is 150 rpm, the adsorption temperature is 25℃, and the adsorption time is 36 h.

[0066] Step S4: Mix coal gangue, municipal sludge, corn stalks, and cow dung to obtain a solid waste matrix with an initial carbon-to-nitrogen ratio of 23:1. Lay the solid waste matrix in an open area into strip-shaped piles, with a height of 0.3m. The particle size of the coal gangue is ≤1mm, and the length of the corn stalks is 3-5cm. On a dry basis, the mass ratio of coal gangue to municipal sludge is 1:1, the total amount of corn stalks and cow dung is 4.2:1 to the mass ratio of coal gangue, and the mass ratio of corn stalks to cow dung is 1:1.

[0067] Step S5: Add the compound microbial agent to the strip-shaped pile and mix evenly. Then, evenly sprinkle the Eisenia fetida seedlings on the surface of the pile. After the compound microbial agent and earthworms are inoculated, fermentation is carried out. During the fermentation period, turn the pile over every 3 days. After the fermentation is completed, sieve and separate the earthworms from the compost.

[0068] Based on the mass of water contained in the solid waste substrate, the inoculum amount of the compound microbial agent is 1 g / kg. (Relative to 1 m³) 2 The surface area of ​​the strip-shaped pile was [not specified], and the inoculation amount of Eisenia fetida seedlings was 1 kg. The fermentation temperature was 24℃, and the fermentation time was 20 days.

[0069] Example 2 Step S1: Inoculate non-decarboxylated Leclercella into sodium carboxymethyl cellulose liquid medium and then culture at 10°C for 80 h; after culture, centrifuge and resuspend the precipitate with physiological saline to obtain non-decarboxylated Leclercella bacterial suspension with absorbance of 1.6. The cold-resistant short bacillus was inoculated in LB liquid medium and then cultured at 35°C for 60 h. After the culture was completed, the precipitate was centrifuged and resuspended in physiological saline to obtain a cold-resistant short bacillus bacterial suspension with an absorbance of 1.5.

[0070] Step S2: Mix the gasification slag and corn straw residue evenly, then impregnate and modify them in a ferrous oxalate solution; remove the impregnated mixture and dry it, then perform a first pyrolysis at a rate of 3℃ / min under a nitrogen atmosphere to the pyrolysis temperature. After the first pyrolysis, perform a second pyrolysis at a rate of 5℃ / min from the first pyrolysis temperature to the second pyrolysis temperature to obtain iron-modified gasification slag-based biochar; the mass ratio of gasification slag to straw residue is 1:0.8, the particle size of the gasification slag is ≤74μm, the particle size of the corn straw residue is ≤74μm, and the concentration of the ferrous oxalate solution is 1 mol·L⁻¹. -1 The impregnation temperature was 28℃, the impregnation time was 20h, the first pyrolysis temperature was 550℃, the first pyrolysis time was 0.8h, the second pyrolysis temperature was 750℃, and the second pyrolysis time was 1.5h.

[0071] Step S3: Mix the non-decarboxylated Leclercella bacterial solution and the frost-resistant Short Bacillus bacterial solution with iron-modified gasification slag-based biochar, adjust the pH to 8, and obtain a mixed solution. Then, place the mixed solution in a shaker for adsorption treatment. After the adsorption treatment is completed, centrifuge to obtain a composite bacterial agent containing non-decarboxylated Leclercella and frost-resistant Short Bacillus, as well as iron-modified gasification slag-based biochar loaded with non-decarboxylated Leclercella and frost-resistant Short Bacillus. The volume ratio of the non-decarboxylated Leclercella bacterial solution to the frost-resistant Short Bacillus bacterial solution is 1:0.8, and the ratio of the total amount of the non-decarboxylated Leclercella bacterial solution and the frost-resistant Short Bacillus bacterial solution to the amount of iron-modified gasification slag-based biochar is 45mL:1g. The shaking speed is 200rpm, the adsorption temperature is 27℃, and the adsorption time is 30h.

[0072] Step S4: Mix coal gangue, municipal sludge, corn stalks and cow dung to obtain a solid waste matrix with an initial carbon-to-nitrogen ratio of 25:1. Lay the solid waste matrix in an open area into strip-shaped piles with a height of 0.2m. The particle size of the coal gangue is ≤1mm, and the length of the corn stalks is 3-5cm. On a dry basis, the mass ratio of coal gangue to municipal sludge is 1:1.2, the mass ratio of the total amount of corn stalks and cow dung to the mass ratio of coal gangue is 5.4:1, and the mass ratio of corn stalks to cow dung is 1:0.9.

[0073] Step S5: Add solid waste-based solidification balls loaded with non-decarboxylated Leclercella and cold-resistant short bacilli to the strip-shaped pile and mix evenly. Then, evenly scatter Eisenia fetida seedlings on the surface of the pile. After inoculating the compound microbial agent and earthworms, fermentation is carried out. Turn the pile over once every 4 days. After fermentation is completed, screen and separate the earthworms from the compost.

[0074] Based on the mass of water contained in the solid waste substrate, the inoculum amount of the compound microbial agent is 0.9 g / kg. Relative to 1 m³ 2 The surface area of ​​the strip-shaped pile was [not specified], the inoculation amount of Eisenia fetida seedlings was 1.2 kg; the fermentation temperature was 22℃, and the fermentation time was 18 days.

[0075] Example 3 Step S1: Inoculate non-decarboxylated Leclercella into the first liquid culture medium and then incubate at 20°C for 60 h; after incubation, centrifuge and resuspend the precipitate with physiological saline to obtain a non-decarboxylated Leclercella bacterial suspension with an absorbance of 1.5. The cold-resistant short bacillus was inoculated in LB liquid medium and then cultured at 25°C for 80 h. After the culture was completed, the precipitate was centrifuged and resuspended in physiological saline to obtain a cold-resistant short bacillus culture with an absorbance of 1.6.

[0076] Step S2: Mix the gasification slag and corn straw residue evenly, then impregnate and modify them in a ferrous oxalate solution; remove the impregnated mixture and dry it, then perform a first pyrolysis at a rate of 10℃ / min under a nitrogen atmosphere to the first pyrolysis temperature. After the first pyrolysis is completed, perform a second pyrolysis at a rate of 1℃ / min from the first pyrolysis temperature to the second pyrolysis temperature to obtain iron-modified gasification slag-based biochar; the mass ratio of gasification slag to straw residue is 1:1.1, the particle size of the gasification slag is ≤74μm, the particle size of the corn straw residue is ≤74μm, and the concentration of the ferrous oxalate solution is 0.1 mol·L⁻¹. -1 The impregnation temperature is 22℃ and the impregnation time is 30h; the first pyrolysis temperature is 450℃ and the first pyrolysis time is 1.2h; the second pyrolysis temperature is 850℃ and the second pyrolysis time is 2.5h.

[0077] Step S3: Mix the non-decarboxylated Leclercella bacterial solution and the frost-resistant Short Bacillus bacterial solution with iron-modified gasification slag-based biochar, adjust the pH to 8, and obtain a mixed solution. Then, place the mixed solution in a shaker for adsorption treatment. After the adsorption treatment is completed, centrifuge to obtain a composite bacterial agent containing non-decarboxylated Leclercella and frost-resistant Short Bacillus, as well as iron-modified gasification slag-based biochar loaded with non-decarboxylated Leclercella and frost-resistant Short Bacillus. The volume ratio of the non-decarboxylated Leclercella bacterial solution to the frost-resistant Short Bacillus bacterial solution is 1:1.2, and the ratio of the total amount of the non-decarboxylated Leclercella bacterial solution and the frost-resistant Short Bacillus bacterial solution to the amount of iron-modified gasification slag-based biochar is 55 mL: 1 g. The shaking speed is 100 rpm, the adsorption temperature is 20℃, and the adsorption time is 30 h.

[0078] Step S4: Mix coal gangue, municipal sludge, corn stalks and sheep manure to obtain a solid waste matrix with an initial carbon-to-nitrogen ratio of 21:1. Lay the solid waste matrix in an open area into strip-shaped piles with a height of 0.4m. The particle size of the coal gangue is ≤1mm, and the length of the corn stalks is 3-5cm. On a dry basis, the mass ratio of coal gangue to municipal sludge is 1:0.6, the mass ratio of the total amount of corn stalks and cow manure to the mass ratio of coal gangue is 1.7:1, and the mass ratio of corn stalks to cow manure is 1:1.1.

[0079] Step S5: Add the compound microbial agent to the strip-shaped pile and mix evenly. Then, evenly sprinkle the Eisenia fetida seedlings on the surface of the pile. After the compound microbial agent and earthworms are inoculated, fermentation is carried out. Turn the pile over every 2 days. After fermentation is completed, sieve and separate the earthworms from the compost.

[0080] Based on the mass of water contained in the solid waste substrate, the inoculum amount of the compound microbial agent is 1.3 g / kg. Relative to 1 m³ 2 The surface area of ​​the strip-shaped pile was [not specified], the inoculation amount of Eisenia fetida seedlings was 0.8 kg; the fermentation temperature was 26℃, and the fermentation time was 22 days.

[0081] Example 4 The composting fermentation was carried out according to the method of Example 1, except that in step S4, the mass ratio of coal gangue to urban sludge on a dry basis was 1:0.5, the mass ratio of corn stalks and cow manure to coal gangue was 1.1:1, and the mass ratio of corn stalks to cow manure was 1:1.2.

[0082] Example 5 The composting fermentation was carried out according to the method of Example 1, except that in step S4, the mass ratio of coal gangue to urban sludge on a dry basis was 1:2, the mass ratio of corn stalks and cow manure to coal gangue was 10.2:1, and the mass ratio of corn stalks to cow manure was 1:0.8.

[0083] Example 6 The composting fermentation was carried out according to the method of Example 1, except that in step S5, relative to 1m 2 The surface area of ​​the strip-shaped pile was such that the inoculation amount of Eisenia fetida seedlings was 1.6 kg.

[0084] Example 7 The composting fermentation was carried out according to the method of Example 1, except that in step S5, relative to 1m 2 The surface area of ​​the strip-shaped pile was such that the inoculation amount of Eisenia fetida seedlings was 0.5 kg.

[0085] Example 8 The composting fermentation was carried out according to the method of Example 1, except that in step S5, the inoculation amount of the compound microbial agent was 0.9 g / Kg, based on the mass of water contained in the solid waste substrate.

[0086] Example 9 The composting fermentation was carried out according to the method of Example 1, except that in step S5, the inoculation amount of the compound microbial agent was 3g / Kg, based on the mass of water contained in the solid waste substrate.

[0087] Comparative Example 1 The composting fermentation was carried out according to the method of Example 1, except that in step S4, the coal gangue was replaced with an equal mass of urban sludge.

[0088] Comparative Example 2 The composting fermentation was carried out according to the method of Example 1, except that in step S4, the coal gangue was replaced with an equal mass of weathered coal.

[0089] Comparative Example 3 The composting fermentation was carried out according to the method of Example 1, except that in step S4, the coal gangue was replaced with an equal mass of coal slime.

[0090] Comparative Example 4 The composting fermentation was carried out according to the method of Example 1, except that in step S2, the iron-modified gasification slag-based biochar was replaced with an equal mass of phosphorus-modified gangue-based biochar. The preparation method of phosphorus-modified gangue-based biochar includes: mixing coal gangue and CaO at a mass ratio of 10:1, ball milling for 30 min to obtain coal gangue powder with a particle size ≤200 mesh; mixing the ball-milled coal gangue powder with 2 mol / L NaOH solution at a solid-liquid ratio of 1 g:30 mL, then adding it to a microwave reactor and activating it by stirring at 160℃ for 40 min to obtain an active aluminosilicate mineral liquid leached from the coal gangue; centrifuging the active aluminosilicate mineral liquid at 8000 r / min for 5 min in a centrifuge, taking out the supernatant for later use, washing and drying the remaining precipitate, and pulverizing it to obtain carbon slag. Weigh out silicon dioxide from coal gangue and SiO2 at a mass ratio of 1:0.1472. Add SiO2 to the suspension to adjust the atomic ratio of sodium, aluminum and silicon in the ore solution to 1:1:2. Continue stirring and aging at room temperature for 4 hours to obtain aged material. Transfer the aged material to a reactor, seal the reactor, and heat it from room temperature to 200℃ at a rate of 5℃ / min for constant temperature crystallization for 10 hours. Filter the reacted material, wash the filtered solid phase, and dry it in an oven at 50℃ for 2 hours to obtain gangue-based zeolite. The obtained carbon slag and gangue-based zeolite were added to straw, and the straw, carbon slag, and gangue-based zeolite were mixed in a mass ratio of 5:2:1 to obtain a mixed raw material. Ca(H2PO4)2 and the mixed raw material were added to distilled water under stirring, and stirring continued for 6 hours. The Ca(H2PO4)2 content in the distilled water was 10 g / L, and the mass ratio of the mixed raw material to Ca(H2PO4)2 was 5:1. The mixture was then dried in an oven at 60℃ until the weight no longer changed after two weighings at 1-hour intervals, yielding phosphorus-modified raw material. The obtained phosphorus-modified raw material was placed in a tubular resistance furnace and heated to 500℃ at a heating rate of 5℃ / min under a N2 atmosphere, and maintained for pyrolysis for 4 hours to obtain phosphorus-modified gangue-based biochar.

[0091] Comparative Example 5 The composting fermentation was carried out according to the method of Example 1, except that steps S2 and S3 were not performed; in step S5, the compound microbial agent was replaced with a mixed microbial solution of non-decarboxylated Leclercella bacterial solution and cold-resistant Short Bacillus bacterial solution (the volume ratio of the mixed microbial solution of non-decarboxylated Leclercella bacterial solution and cold-resistant Short Bacillus bacterial solution was 1:1), and the inoculation amount of the mixed microbial solution was 50 mL / Kg based on the mass of water contained in the solid waste substrate.

[0092] Comparative Example 6 The composting fermentation was carried out according to the method of Example 1, except that in step S5, the compound microbial agent was not inoculated.

[0093] Comparative Example 7 The composting fermentation was carried out according to the method of Example 1, except that in step S5, the compound microbial agent was replaced with an equal mass of organic material composting agent (straw type) purchased from Zhongnong Lvkang (Beijing) Biotechnology Co., Ltd.

[0094] Comparative Example 8 The composting fermentation was carried out according to the method of Example 1, except that in step S3, the non-decarboxylated Leclercella bacterial solution was replaced with a cold-resistant short bacillus bacterial solution with equal absorbance and volume.

[0095] Comparative Example 9 The composting fermentation was carried out according to the method of Example 1, except that in step S3, the cold-resistant short bacillus bacterial solution was replaced with non-decarboxylated Leclercella bacterial solution with equal absorbance and volume.

[0096] Comparative Example 10 The composting fermentation was carried out according to the method of Example 1, except that earthworm seedlings were not inoculated in step S5.

[0097] Test Example 1 The heavy metal content in sludge, coal gangue, coal slime, and weathered coal was determined according to the Tessier five-step method in "Environmental Soil Science (Third Edition)". The test results are shown in Table 1.

[0098] The pH value, C / N ratio, and seed germination index of the compost products prepared in the above examples and comparative examples were determined according to the standard methods specified in NY 525-2021 "Organic Fertilizers". The experimental data were analyzed using SPSS 26.0 with one-way ANOVA, and P < 0.05 was used as the criterion for statistical significance. Different lowercase letters were used to distinguish differences between treatments in multiple comparisons. If two treatments shared the same lowercase letter, the difference was not significant at the P < 0.05 level; if no lowercase letter was shared, the difference was significant. Specifically, pH value was determined using the potentiostatic method; organic carbon content was determined using the potassium dichromate oxidation-external heating method; total nitrogen content was determined using the Kjeldahl method; and seed germination index was determined using the extract seed germination test method. The test results are shown in Tables 2 and 3.

[0099] The contents of different forms of arsenic and mercury in compost products were determined according to the Tessier five-step method in "Environmental Soil Science (Third Edition)". The test results are shown in Tables 2 and 3. The formula for the passivation rate of active heavy metals is: IR(%) = (R b R a ) / R b ×100; Where: IR—heavy metal passivation rate (%); Rb —Percentage of exchangeable heavy metals before composting (%); R a —Percentage of exchangeable heavy metals after composting (%).

[0100] Test Example 2 The relative abundance of proteinophilic bacteria and slaughter bacilli in the compost products prepared in the above examples and comparative examples was detected, and the results are shown in Table 4. The relative abundance was determined by 16S rRNA amplicon analysis by Shenzhen Micro-Med Technology Group Co., Ltd., China.

[0101] Test Example 3 Pot experiments were conducted using the compost prepared in the above-described embodiments and comparative examples.

[0102] Step 1: Sieve the prepared compost to a particle size of <1mm.

[0103] Step 2: Select suburban soil from Dalad Banner, Ordos City, sieve it to a particle size of <1mm, add compost to the soil at an 8wt% addition rate, mix thoroughly, and fill into 1kg plastic gallon pots to obtain the treatment group. Use pure soil as a control, and set up 3 parallel samples for both the control group and the treatment group.

[0104] Step 3: Soak alfalfa seeds in 10% H2O2 for 10 minutes, then rinse them thoroughly with deionized water. Place 90 alfalfa seeds evenly in each pot, burying them 1-2 cm deep.

[0105] Step 4: Measure the maximum moisture content of each treatment using the gravimetric method, and maintain the maximum moisture content at 80% during the experiment. Step 5: Place the potted plants with different treatments on the plant tissue culture rack, and set the optimal light intensity for alfalfa growth to DLI = 23.328 mol / (m²). 2 ·d) That is, PPFD = 405 μmol / m 2 / s, light duration 16h, darkness duration 8h.

[0106] Step 6: After one month of pot cultivation, samples of alfalfa were taken for testing. Plant height was measured using the ruler method described in "Introduction to Environmental Protection," and biomass was determined using the oven-drying constant weight method to verify the growth-promoting effect of the substrate. The test results are shown below. Figure 1 .

[0107] Table 1

[0108] Table 2

[0109] Table 3

[0110] Table 4

[0111] As shown in Tables 1-3, the composting prepared using the method of the present invention can effectively improve the seed germination index (reaching over 125%) and the passivation rate of active heavy metals (the passivation rate of active arsenic can reach over 6%; the passivation rate of active mercury can reach over 8%), the carbon-nitrogen conversion rate in the solid waste matrix (C / N can reach 11:1 to 16:1), and the pH of the compost product is stable between 6 and 7. The method of the present invention also effectively improves the relative abundance of proteinophilic bacteria and septicemia in the compost product, further improving the fermentation effect of the compost product.

[0112] Compost prepared using the preferred technical solutions of this invention (Examples 1-3) can further improve seed germination index (reaching over 143%) and passivation rate of active heavy metals (active arsenic passivation rate reaching over 17%, and active mercury passivation rate reaching over 19%), carbon-nitrogen conversion rate in solid waste matrix (C / N ratio reaching 14 to 16), and earthworm yield reaching over 7.4 kg / t. 16S rRNA amplicon analysis shows that the relative abundance of proteinophilic bacteria in the compost product can reach 6.7%, and the relative abundance of *Bacillus septicemia* can reach 7.69%. (See attached...) Figure 1 It is known that compost prepared using the method of the present invention can effectively increase plant height and biomass.

[0113] In step S5 of Example 6, relative to 1m 2 The surface area of ​​the strip-shaped compost pile was [not specified]. The inoculation amount of Eisenia fetida seedlings was 1.6 kg. In Example 1 of this invention, the inoculation amount of Eisenia fetida seedlings was 1 kg. Compared with Example 6, the seed germination index of the compost product prepared in Example 1 increased by 6.7%, the earthworm yield increased by 6.6%, the passivation rate of active arsenic increased by 11.39%, the passivation rate of active mercury increased by 8.01%, and the C / N ratio of the compost product reached 15.7:1, which effectively improved the composting fermentation effect.

[0114] Compared to Comparative Example 1, where coal gangue was replaced with an equal mass of municipal sludge in step S4, Example 1 of the present invention uses a mixture of coal gangue, municipal sludge, straw, and cow manure, inoculated with a compound microbial agent and earthworms, which can effectively improve the composting fermentation effect. Compared to Comparative Example 1, the compost product prepared in Example 1 showed a 26.3% increase in seed germination index, a 47.43% increase in earthworm yield, a 0.78% increase in active arsenic passivation rate, a 0.57% increase in active mercury passivation rate, and a C / N ratio of 15.7:1. Furthermore, in pot experiments, it significantly improved plant height and biomass.

[0115] In step S4 of Comparative Example 2, coal gangue was replaced with an equal mass of weathered coal. In step S4 of Example 1 of the present invention, coal gangue was used. Compared with Comparative Example 2, the seed germination index of the compost product prepared in Example 1 increased by 20.26%, earthworm yield increased by 16.93%, active arsenic passivation rate increased by 1.64%, active mercury passivation rate increased by 2.16%, and the C / N ratio of the compost product reached 15.7:1, which effectively improved the composting fermentation effect.

[0116] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for composting and fermenting using earthworms and compound microbial agents, characterized in that, The method involves inoculating earthworms and compound microbial agents into a solid waste substrate for fermentation to produce compost; The solid waste substrate includes coal gangue, sludge, and organic matter; The compound microbial agent includes non-decarboxylated Leclercella, cold-resistant short bacilli, and biochar loaded with non-decarboxylated Leclercella and cold-resistant short bacilli; The non-decarboxylating Leclercella bacteria are classified and named as non-decarboxylating Leclercella. Leclercia adecarboxylata The accession number is CGMCC No. 36871; The preservation number of the cold-resistant short bacillus is SHBCC D71512; The organic matter includes straw; the fermentation temperature is ≤35℃.

2. The method according to claim 1, characterized in that, The 16S rDNA sequence of the non-decarboxylated Leclercella is shown in SEQ ID NO.1; And / or, on a dry basis, the mass ratio of the coal gangue, sludge and organic matter is 1:0.5-2:1-11, preferably 1:0.6-1.2:1.5-5.5; And / or, the moisture content of the solid waste substrate is 45wt%-65wt%, preferably 45wt%-55wt%; And / or, the carbon-to-nitrogen ratio of the solid waste matrix is ​​21-27:1; And / or, the particle size of the coal gangue is ≤5mm, preferably ≤1mm; And / or, the length of the straw is 3-5 cm; And / or, the organic matter also includes animal feces; Preferably, the mass ratio of straw to animal manure, on a dry basis, is 1:0.8-1.2; And / or, the straw is selected from at least one of corn straw, wheat straw, sugarcane straw and rice straw, preferably corn straw; And / or, the animal excrement is preferably selected from at least one of sheep manure, cow manure, chicken manure, pig manure and pigeon manure, with cow manure being the most preferred; And / or, the sludge is selected from municipal sludge.

3. The method according to claim 1 or 2, characterized in that, The biochar is selected from iron-modified gasification slag-based biochar. Preferably, the preparation method of the compound microbial agent includes the following steps: Step S1: After expanding the culture of the non-decarboxylated Leclercella, centrifuge to collect the bacterial cells, and resuspend the bacterial cells in 0.85% saline solution to obtain a non-decarboxylated Leclercella bacterial solution; After the cold-resistant short bacillus was expanded and centrifuged, the bacterial cells were resuspended in 0.85% saline solution to obtain the cold-resistant short bacillus bacterial solution. Step S2: Mix the gasification slag and straw residue evenly, and then impregnate them in ferrous oxalate solution for modification; take out the impregnated mixture and dry it, and then carry out the first pyrolysis and second pyrolysis treatment in an inert atmosphere to obtain iron-modified gasification slag-based biochar. Step S3: Mix the non-decarboxylated Leclercella bacterial solution and the frost-resistant Short Bacillus bacterial solution with iron-modified gasification slag-based biochar to obtain a mixed liquid. Then, place the mixed liquid in a shaker for adsorption treatment. After the adsorption treatment is completed, centrifuge to obtain a composite bacterial agent containing non-decarboxylated Leclercella and frost-resistant Short Bacillus, as well as iron-modified gasification slag-based biochar loaded with non-decarboxylated Leclercella and frost-resistant Short Bacillus.

4. The method according to claim 3, characterized in that, In step S1, the absorbance of the non-decarboxylated Leclercella bacterial solution is 1.0-2.0, preferably 1.5-1.6; And / or, in step S1, the absorbance of the cold-resistant short bacillus bacterial solution is 1.0-2.0, preferably 1.5-1.6; And / or, in step S1, the non-decarboxylated Leclercella is propagated using a first liquid culture medium, the formulation of which is: peptone 1-4 g / L, sodium carboxymethyl cellulose 3-10 g / L, potassium dihydrogen phosphate 0.5-2 g / L, magnesium sulfate heptahydrate 0.3-1.0 g / L, sodium chloride 0.3-1 g / L, pH 6-9; And / or, in step S1, the method for expanding the non-decarboxylated Leclercella includes: inoculating the non-decarboxylated Leclercella into a first liquid culture medium, and then culturing it at 10-20°C for 60-80 hours; And / or, in step S1, the cold-resistant short bacillus is expanded using a second liquid culture medium, the second liquid culture medium being LB liquid culture medium, and the method for expanding the cold-resistant short bacillus includes: inoculating the cold-resistant short bacillus into LB liquid culture medium, and then culturing it at 25-35℃ for 60-80h.

5. The method according to claim 3 or 4, characterized in that, In step S2, the mass ratio of the gasification slag to the straw slag is 1:0.5-2, preferably 1:0.8-1.1; And / or, in step S2, the particle size of the gasification slag is ≤150μm, preferably ≤74μm; And / or, in step S2, the particle size of the straw residue is ≤150μm, preferably ≤74μm; Preferably, in step S2, the straw residue is selected from at least one of corn straw residue, wheat straw residue, sugarcane straw residue, and rice straw residue, and is preferably corn straw residue; And / or, in step S2, the concentration of the ferrous oxalate solution is 0.3-1.0 mol·L⁻¹. -1 ; And / or, in step S2, the conditions for the impregnation modification include: an impregnation temperature of 22-28°C and an impregnation time of 20-30 hours; And / or, in step S2, the conditions for the first pyrolysis include: a pyrolysis temperature of 400-600℃, preferably 450-550℃; and a pyrolysis time of 0.5-1.5h, preferably 0.8-1.2h. And / or, in step S2, the method further includes: before the first pyrolysis, heating to the first pyrolysis temperature at a rate of 3-10℃ / min in an inert atmosphere; And / or, in step S2, the method further includes: before the second pyrolysis, raising the temperature from the first pyrolysis temperature to the second pyrolysis temperature at a rate of 1-5℃ / min in an inert atmosphere; And / or, in step S2, the conditions for the second pyrolysis include: a pyrolysis temperature of 700-900℃, preferably 750-850℃; and a pyrolysis time of 1-3h, preferably 1.5-2.5h. And / or, in step S2, the inert atmosphere is selected from at least one of nitrogen atmosphere, helium atmosphere, neon atmosphere and argon atmosphere.

6. The method according to any one of claims 3-5, characterized in that, In step S3, the volume ratio of the non-decarboxylated Leclercella bacterial suspension to the frost-resistant Short Bacillus bacterial suspension is 1:0.8-1.2; And / or, in step S3, the total amount of the non-decarboxylated Leclercella bacterial solution and the frost-resistant Short Bacillus bacterial solution to the amount of iron-modified gasification slag-based biochar is (40-70) mL:1g, preferably (45-55) mL:1g; And / or, in step S3, the conditions for the adsorption treatment include: an adsorption temperature of 20-35℃, preferably 23-27℃; and an adsorption time of 6-72h, preferably 30-40h. And / or, in step S3, the rotational speed of the shaker is 140-200 rpm; And / or, in step S3, the pH value of the mixture is 7.5-8.

5.

7. The method according to any one of claims 1-6, characterized in that, The amount of the compound microbial agent inoculated with the solid waste substrate, based on the mass of water it contains, is 0.9-3 g / kg, preferably 0.9-1.3 g / kg.

8. The method according to any one of claims 1-7, characterized in that, The composting fermentation method further includes: before inoculation, laying the solid waste substrate into a pile, preferably laying it into a strip pile; Preferably, the height of the pile is 0.2-0.4m; And / or, relative to 1m 2 The surface area of ​​the strip-shaped pile, and the inoculation amount of the earthworm seedlings is 0.5-1.6 kg, preferably 0.8-1.2 kg; And / or, the earthworms are inoculated into the solid waste substrate in the form of earthworm seedlings, and the earthworms are selected from at least one of Eisenia fetida, Pheretima filamentosa, Pheretima eugenoptera, and Pheretima burrowing, preferably Eisenia fetida; And / or, the fermentation conditions include: fermentation temperature ≤35℃, preferably 22-26℃, and fermentation time of 16-24d, preferably 18-22d; And / or, the composting fermentation method further includes: turning the strip-shaped pile during the fermentation process; Preferably, the pile is turned over once every 3-5 days; And / or, the composting fermentation method further includes: after fermentation is completed, screening and separating earthworms from the compost.

9. Compost prepared by any one of the composting fermentation methods according to claims 1-8.

10. The application of the compost prepared by the composting fermentation method according to any one of claims 1-8 or the compost according to claim 9 in soil improvement.

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