1. The compound high-temperature microbial inoculum is characterized by comprising iron reducing bacteria and iron minerals;

the iron-reducing bacteria are preferably thermophilic iron-reducing bacteria; the iron-reducing bacteria are more preferably facultative aerobic bacteria.

2. The complex hyperthermophilic agent of claim 1, wherein the thermophilic iron reducing bacteria comprises at least one of Bacillus composi and Bacillus thermophilus.

3. The complex pyrobacterial agent according to claim 1, wherein the iron mineral includes at least one of hematite, lepidocrocite, ferrihydrite, and goethite;

the mass ratio of the iron mineral in the composite high-temperature microbial inoculum is preferably 2-10%.

4. The complex thermophilic bacterial agent of claim 1, wherein the fermentation medium components for culturing the iron reducing bacteria comprise medium nutrients and a conditioner;

wherein, the nutrient components of the culture medium preferably comprise sodium dihydrogen phosphate, ammonium chloride, potassium chloride, yeast extract and glucose;

the conditioning agent preferably comprises soy cake flour.

5. The composite high temperature microbial inoculum of claim 1, wherein the bacterial content of iron reducing bacteria in the composite high temperature microbial inoculum is 10⁶～10⁹cfu/g。

6. The method for preparing the composite high-temperature microbial inoculum of any one of claims 1 to 6, comprising the following steps:

inoculating thermophilic iron reducing bacteria to a culture medium, carrying out anaerobic fermentation at 45-50 ℃ for 48-96 hours, and adding 3-6% of a conditioner after the fermentation is finished to obtain the product;

wherein, the preparation method also preferably comprises the step of adjusting the water content to be 45-55% after the conditioner is added.

7. A method for composting and degrading micro-plastics comprises the following steps:

mixing the composite high-temperature microbial inoculum of any one of claims 1 to 5 with organic solid waste for fermentation;

the mixing mass ratio of the composite high-temperature microbial inoculum to the organic solid waste is preferably (1-5): (95-99).

8. The method of claim 7, wherein the organic solid waste comprises plastic-containing municipal sludge, livestock manure, agricultural residues, kitchen waste.

9. The use of the complex high-temperature microbial inoculum of any one of claims 1 to 5 in high-temperature composting.

10. The use of the composite high temperature microbial inoculum of any one of claims 1 to 5 in plastic degradation.

Background

Microplastics (MPs) are plastic particles with a size of less than 5mm, which are nowadays a widely distributed new class of pollutants. The MPs are small in particle size and large in quantity, contain toxic additives, are easily eaten or absorbed by organisms in the environment to cause physiological damage, and easily adsorb other pollutants to form a pollutant complex which migrates in the environment and is harmful to human health through a food chain. MPs are mainly present in organic solid wastes such as household garbage, excrement, municipal sludge and the like. According to investigation, the concentration of the micro-plastic in the municipal sludge can reach 1.6-5.6 multiplied by 10⁴Every kilogram of sludge (dry weight) has about 4.4-43 million tons of MPs per year, and the MPs enter the soil environment along with organic solid waste landfill, land utilization or other garbage treatment processes, so that the physical and chemical properties of the soil are changed, the soil function and biological diversity are damaged, and the ecological and food chain risks are caused.

The compost can promote the humification of organic matters, is an important means for recycling organic solid wastes, and is an important 'barrier' for preventing pollutants in the organic solid wastes from entering the soil and other environments. The essence of the compost is a process of utilizing organic matters humification and pollutant degradation driven by microorganisms to generate heat energy, and in related documents, the compost can effectively remove pentachlorophenol in organic solid waste and eliminate antibiotics and resistance genes, and has an excellent environment purification effect. However, most of the MPs are high-molecular polymers with strong hydrophobicity, and most of microorganisms have low degradation rate in natural environment, so that the micro-plastics cannot be removed in the actual composting process.

Therefore, the development of a microbial inoculum capable of improving the removal efficiency of the micro-plastics in the organic solid waste composting process has important practical significance for the prevention and control of micro-plastic pollution and the protection of soil ecological environment.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art described above. Therefore, the invention provides a composite high-temperature microbial inoculum and application thereof in plastic degradation. The composite high-temperature microbial inoculum contains thermophilic iron reducing bacteria and iron minerals, wherein the thermophilic iron reducing bacteria can utilize nutrient substances of organic solid wastes in compost to carry out growth and propagation, iron oxidation reduction circulation is driven in the dynamic change process of compost aerobic-anoxic reaction, a large amount of OH (hydroxyl free radicals) are generated by the iron minerals, the surface hydrophobicity of micro plastic materials in the compost is damaged, the oxidative degradation of the micro plastic in the compost is promoted, and the efficient removal of the compost micro plastic is realized.

In a first aspect of the present invention, a complex high temperature microbial inoculum is provided, which contains iron reducing bacteria and iron minerals.

Hydroxyl radicals (. OH) are transient radicals which are common in the environment and are also oxidizingThe most reactive oxygen Radicals (ROS) play a non-negligible role in driving the conversion of pollutants in the environment. Because the Fe (II) mineral and reducing organic matter in the environment can react with O when being disturbed₂The reaction, via Fenton and Haber-Weiss pathways, produces a large amount of OH. These OH groups promote chemical bond cleavage of MPs and deep mineralization into water and carbon dioxide. In an aerobic-anaerobic alternate environment, the iron redox cycle driven by the iron reducing bacteria can promote the continuous generation of OH in the environment, and realize the effective removal of environmental pollutants. In the related technology, the microorganism-iron redox cycle OH production system can only be under the normal temperature condition (temperature)<The temperature is 40 ℃, and the method is difficult to be applied to high-temperature environments such as compost and the like. According to the invention, the high-temperature compost of the organic solid waste can be used for providing nutrients required by microbial growth, the oxygen reaching the core of compost particles is extremely low due to uneven mass transfer in the composting process, an aerobic-anoxic reaction interface required by microbial-driven iron redox cycling reaction is formed in the compost particles, and the aerobic-anoxic reaction interface is dynamically changed along with the changes of compost temperature, water content, aeration amount, turning and the like, so that a microbial-iron mineral mediated plastic degradation system which is convenient to control and suitable for high-temperature compost can be obtained.

According to a first aspect of the invention, in some embodiments of the invention, the iron-reducing bacteria are thermophilic iron-reducing bacteria.

In some preferred embodiments of the present invention, the iron-reducing bacteria are facultative aerobic bacteria.

In some more preferred embodiments of the present invention, the thermophilic iron-reducing bacterium comprises at least one of Bacillus composi and Bacillus thermophilus.

In some more preferred embodiments of the present invention, the thermophilic iron-reducing bacterium is at least one of Bacillus composi SgZ-9 and Bacillus thermophilus SgZ-10

Of course, the skilled in the art can reasonably select other thermophilic iron reducing bacteria mode strains for reasonable replacement according to the actual use requirements, and the thermophilic iron reducing bacteria in the invention include but are not limited to Bacillus composi SgZ-9 and Bacillus thermophilus SgZ-10.

According to a first aspect of the invention, in some embodiments of the invention, the iron mineral comprises at least one of hematite, lepidocrocite, ferrihydrite and goethite.

The chemical component of Hematite (Hematite) is Fe₂O₃Oxide minerals belonging to the hexagonal system; the chemical composition of the lepidocrocite is gamma-FeO (OH), the lepidocrocite contains 89.9 percent of ferric oxide, and the crystal belongs to an orthorhombic system and is crystallized into a gamma-phase hydroxide mineral; ferrihydrite is a weakly crystalline iron hydroxide, usually Fe³⁺The first precipitate to appear during hydrolysis; goethite is a widely distributed mineral, as a hydrated iron oxide, with a chemical composition of α -feo (oh). Of course, those skilled in the art can reasonably select other iron minerals for reasonable replacement according to actual use requirements, and the iron minerals in the invention include, but are not limited to hematite, lepidocrocite, ferrihydrite and goethite.

In some preferred embodiments of the present invention, the mass ratio of the iron mineral in the composite high temperature microbial inoculum is 2% to 10%.

Of course, the mass ratio of the iron mineral in the composite high-temperature microbial inoculum can be reasonably adjusted by a person skilled in the art according to the actual use requirement, so that the iron mineral can obtain a better use effect.

In some preferred embodiments of the invention, the fermentation medium components used to culture the iron-reducing bacteria include medium nutrients and conditioners.

In some more preferred embodiments of the invention, the medium nutrients include, but are not limited to, sodium dihydrogen phosphate, ammonium chloride, potassium chloride, yeast extract, glucose.

Such conditioning agents include, but are not limited to, legume meal.

In some more preferred embodiments of the present invention, the formula of the anaerobic fermentation medium of the thermophilic iron reducing bacteria in the composite high temperature microbial inoculum is as follows: mixing 0.6g/L sodium dihydrogen phosphate, 0.25g/L ammonium chloride, 0.1g/L potassium chloride, 0.2g/L yeast extract and 0.5g/L glucose, adding 2-6% (by mass) iron mineral, adjusting pH to 7.0-7.5, and fermenting. And adding 3-6% (mass ratio) of bean cake powder after fermentation.

In some preferred embodiments of the present invention, the bacterial content of the iron-reducing bacteria in the complex high temperature microbial inoculum is 10⁶～10⁹cfu/g。

The composite high-temperature microbial inoculum can grow and propagate facultative aerobic thermophilic iron reducing bacteria in aerobic condition by directly utilizing nutrient substances in organic solid wastes such as municipal sludge, livestock and poultry manure, agricultural residues, kitchen waste and the like, oxidize Fe (II) of iron minerals in the composite high-temperature microbial inoculum into Fe (III), generate OH, destroy the surface hydrophobicity of plastic materials, and promote the oxidative degradation of micro-plastics in compost. Under the anoxic condition, the thermophilic iron reducing bacteria reduce Fe (III) into Fe (II), and the iron redox cycle is completed. Therefore, the dynamic change of an aerobic-anoxic area in the composting process can be changed by matching with the composting processes such as aeration, turning and the like in the composting process, the continuous production of OH in iron redox cycle in the composting is promoted, and the further efficient removal of compost micro-plastics is realized.

In a second aspect of the present invention, there is provided a method for preparing the complex thermophilic bacterial agent described in the first aspect of the present invention, comprising the following steps:

inoculating thermophilic iron reducing bacteria to a culture medium, carrying out anaerobic fermentation at 45-50 ℃ for 48-96 hours, and adding 3-6% of conditioner after the fermentation is finished, thus obtaining the product.

According to a second aspect of the invention, in some embodiments of the invention, the preparation method further comprises adjusting the moisture content to 45% to 55% after adding the conditioner.

In some more preferred embodiments of the present invention, the preparation method is specifically:

preparing a thermophilic iron reducing bacterium seed solution;

preparing an anaerobic fermentation culture medium of the thermophilic iron reducing bacteria;

inoculating the thermophilic iron reducing bacteria seed liquid into an anaerobic fermentation culture medium according to the inoculation amount of about 1.5 percent (volume ratio), carrying out anaerobic fermentation for 48-96 hours at the temperature of 45-50 ℃, adding 3-6 percent of conditioner after the fermentation is finished, uniformly stirring, and adjusting the water content to ensure that the water content is 45-55 percent.

The mode of plate and frame filter pressing can be adopted in the adjustment of the moisture content, and certainly, other conventional moisture content adjustment modes can be adopted by a person skilled in the art according to actual use requirements.

In a third aspect of the invention, there is provided a method of composting degraded micro-plastics comprising the steps of:

the composite high-temperature microbial inoculum of the first aspect of the invention is mixed with organic solid waste for fermentation.

The inventors have found that hydroxyl radicals start to be produced in large quantities when the compost is exposed to a high temperature period (greater than 65 ℃) at which fermentation starts.

According to the third aspect of the invention, in some embodiments of the invention, the mixing mass ratio of the composite high-temperature microbial inoculum to the organic solid waste is (1-5): (95-99).

According to a third aspect of the invention, in some embodiments of the invention, the organic solid waste comprises plastic-containing municipal sludge, livestock manure, agricultural residues, kitchen waste.

In a fourth aspect of the invention, the application of the composite high temperature microbial inoculum of the first aspect of the invention in high temperature composting is provided.

Under the aerobic condition, the composite high-temperature microbial inoculum can consume nutrient substances in wastes such as municipal sludge, livestock and poultry manure, agricultural residues, kitchen waste and the like through the action of microorganisms to grow and reproduce, so that the wastes are effectively decomposed, and the harm of the wastes to the environment is reduced.

In a fifth aspect of the invention, the application of the complex high temperature microbial inoculum of the first aspect of the invention in plastic degradation is provided.

The composite high-temperature microbial inoculum can grow and propagate facultative aerobic thermophilic iron reducing bacteria in aerobic condition by directly utilizing nutrient substances in organic solid wastes such as municipal sludge, livestock and poultry manure, agricultural residues, kitchen waste and the like, and Fe (II) of iron minerals in the composite high-temperature microbial inoculum is oxidized into Fe (III), OH is generated, the surface hydrophobicity of plastic materials is destroyed, and the oxidative degradation of micro plastic in compost is promoted. Under the anoxic condition, the thermophilic iron reducing bacteria reduce Fe (III) into Fe (II), and the iron redox cycle is completed. Therefore, the dynamic change of an aerobic-anoxic area in the composting process can be changed by matching with the composting processes such as aeration, turning and the like in the composting process, the continuous production of OH in iron redox cycle in the composting is promoted, and the further efficient removal of compost micro-plastics is realized.

The invention has the beneficial effects that:

1. the composite high-temperature microbial inoculum can utilize nutrient substances in organic solid wastes to perform microbial colonization growth under aerobic conditions, and utilizes iron minerals to generate OH, so that the surface hydrophobicity of plastic materials is damaged, and the oxidative degradation of micro plastics in compost is promoted.

2. The composite high-temperature microbial inoculum can be matched with composting processes such as aeration, turning and the like in the composting process, change the dynamic change of an aerobic-anoxic area in the composting process, and promote the continuous production of OH in iron redox circulation in the composting, thereby realizing the further efficient removal of compost micro-plastics.

3. The compound high-temperature microbial inoculum can overcome the problem that the generation of OH in a microorganism-iron redox cycle under a high-temperature environment can not be realized in the related technology, thereby effectively widening the application range of the microorganism-iron redox cycle and providing more theoretical support for environmental pollution treatment and plastic degradation process development.

Drawings

FIG. 1 is a curve showing the difference between the contents of hydroxyl radicals in compost in an experimental group and a control group to which a complex high-temperature microbial inoculum is added in the example of the present invention;

FIG. 2 is a graph showing the change of the content of the micro-plastic in the compost of the experimental group and the control group to which the compound high-temperature microbial inoculum is added in the example of the invention;

FIG. 3 is a curve showing the difference in the content of hydroxyl radicals in chicken manure compost of an experimental group to which a composite high-temperature microbial inoculum is added in an embodiment of the present invention;

FIG. 4 is a graph showing the change in molecular mass of a polystyrene microplastic sheet after composting with a composite high-temperature microbial inoculum in an embodiment of the present invention;

FIG. 5 is a diagram showing the variation of surface groups of a polystyrene microplastic sheet after composting in an embodiment of the present invention, wherein A is the variation of carbon-oxygen element, and B is the variation of carbon-carbon bond, carbon-oxygen single bond, and carbon-oxygen double bond;

fig. 6 shows the surface topography of the composted polystyrene microplastic sheet in the example of the invention, wherein a is a control group and B is an experimental group.

Detailed Description

In order to make the objects, technical solutions and technical effects of the present invention more clear, the present invention will be described in further detail with reference to specific embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

The experimental materials and reagents used are, unless otherwise specified, all consumables and reagents which are conventionally available from commercial sources.

Experimental Material

The information on the strains used in the following examples is shown in Table 1.

TABLE 1 information on the strains used in the experiments

Strain name	Strain deposit number
		Bacillus composti SgZ-9	CCTCC AB2012109
Bacillus thermophilus SgZ-10	CCTCC AB2012110

The composition of the LB medium in the following examples was: tryptone 10.0g/L, yeast extract (yeast powder, available from Aladdin) 5.0g/L, NaCl 10.0.0 g/L, pH 7.0, and sterilizing at 121 deg.C under 0.15MPa for 30 min.

Example 1 preparation of composite Thermomycete

The preparation method comprises the following steps:

(1) preparing a seed solution:

the concentration is 10% according to the inoculation amount of 2%⁸Inoculating cfu/mL Bacillus composi SgZ-9 bacterial liquid into a container filled with LB culture medium, fermenting for 48 hours at 50 ℃, introducing air in the fermentation process, and ensuring the ventilation quantity to be 20-100m³And/h, continuously stirring at the speed of 180-.

(2) Preparing an anaerobic fermentation culture medium:

mixing 0.6g/L sodium dihydrogen phosphate, 0.25g/L ammonium chloride, 0.1g/L potassium chloride, 0.2g/L yeast extract (yeast powder from Allantin), and 0.5g/L glucose, adding 3% (by mass) ferrihydrite, adjusting pH to 7.0, and stirring. Introducing nitrogen/carbon dioxide mixed gas into the culture medium, sterilizing at 100 deg.C for 45 min, and cooling to 80 deg.C for use.

(3) Inoculating the Bacillus composti SgZ-9 seed liquid prepared in the step (1) to the anaerobic fermentation culture medium prepared in the step (2) according to the inoculation amount (volume ratio) of 1.5%, and carrying out anaerobic fermentation for 72 hours at 50 ℃. After fermentation is finished, 4 percent (mass ratio) of bean cake powder is added as a conditioner, and after uniform stirring, the final water content of the composite high-temperature microbial inoculum is controlled to be 45-55 percent through plate-and-frame filter pressing.

The prepared composite high-temperature microbial inoculum is subjected to plate counting and test tube detection, and the bacterial amount of Bacillus compositi SgZ-9 in the prepared composite high-temperature microbial inoculum is about 1.4 multiplied by 10⁸cfu/g。

Example 2 preparation of composite high-temperature microbial inoculum

The preparation method comprises the following steps:

(1) preparing a seed solution:

the concentration is 10% according to the inoculation amount of 2%⁸Inoculating cfu/mL Bacillus thermophilus SgZ-10 bacterial liquid into a container filled with LB culture medium, fermenting at 50 ℃ for 48 hours, introducing air during fermentation, and ensuring the ventilation quantity to be 20-100m³And/h, continuously stirring at the speed of 180-.

(2) Preparing an anaerobic fermentation culture medium:

mixing 0.6g/L sodium dihydrogen phosphate, 0.25g/L ammonium chloride, 0.1g/L potassium chloride, 0.2g/L yeast extract (yeast powder from Allantin), and 0.5g/L glucose, adding 5% (by mass) hematite, adjusting pH to 7.5, and stirring. Introducing nitrogen/carbon dioxide mixed gas into the culture medium, sterilizing at 100 deg.C for 45 min, and cooling to 80 deg.C for use.

(3) Inoculating the Bacillus thermophilus SgZ-10 seed solution prepared in the step (1) to the anaerobic fermentation culture medium prepared in the step (2) according to the inoculation amount (volume ratio) of 1.5%, and performing anaerobic fermentation for 48 hours at 50 ℃. After fermentation is finished, 5 percent (mass ratio) of bean cake powder is added as a conditioner, and after uniform stirring, the final water content of the composite high-temperature microbial inoculum is controlled to be 45-55 percent through plate-and-frame filter pressing.

The prepared composite high temperature microbial inoculum is subjected to plate counting and test tube detection, and the bacterial amount of Bacillus thermophilus SgZ-10 in the prepared composite high temperature microbial inoculum is about 8.3 multiplied by 10⁷cfu/g。

Example 3 preparation of Complex Thermomicrobial inoculum

The preparation method comprises the following steps:

(1) preparing a seed solution:

the concentration of each strain was adjusted to 10% at an inoculum size of 2% per strain⁸Bacterial fluid of cfu/mL Bacillus composti SgZ-9 and concentration of 10⁸Inoculating cfu/mL Bacillus thermophilus SgZ-10 bacterial liquid into containers filled with LB culture medium, fermenting at 50 deg.C for 24 hr, introducing air during fermentation, and ventilating at 20-100m³And/h, continuously stirring at the speed of 180-.

(2) Preparing an anaerobic fermentation culture medium:

mixing 0.6g/L sodium dihydrogen phosphate, 0.25g/L ammonium chloride, 0.1g/L potassium chloride, 0.2g/L yeast extract (yeast powder from Aladdin), 0.5g/L glucose, adding 2% (mass ratio) hematite and 3% (mass ratio) ferrihydrite, adjusting pH to 7.0, and stirring well. Introducing nitrogen/carbon dioxide mixed gas into the culture medium, sterilizing at 100 deg.C for 45 min, and cooling to 80 deg.C for use.

(3) And (2) inoculating the seed liquid of the Bacillus composi SgZ-9 and the Bacillus thermophilus SgZ-10 prepared in the step (1) to the anaerobic fermentation culture medium prepared in the step (2) together according to the inoculation amount (volume ratio) of 1.5% of each strain, and performing anaerobic fermentation for 72 hours at 50 ℃. After fermentation is finished, 5 percent (mass ratio) of bean cake powder is added as a conditioner, and after uniform stirring, the final water content of the composite high-temperature microbial inoculum is controlled to be 45-55 percent through plate-and-frame filter pressing.

The prepared composite high-temperature microbial inoculum is subjected to plate counting and test tube detection, and the bacterial amount of Bacillus compositi SgZ-9 in the prepared composite high-temperature microbial inoculum is about 5.6 multiplied by 10⁸The bacterial amount of cfu/g, Bacillus thermophilus SgZ-10 is about 1.8 multiplied by 10⁷cfu/g。

Effect test of composite high-temperature microbial inoculum

(1) The effect of the composite high-temperature microbial inoculum on removing micro-plastics in sludge compost is as follows:

in this example, the detection object is municipal sludge obtained from a sewage treatment plant in fuzhou, and the basic properties of the sludge are detected by a conventional detection method in the field, and the results are shown in table 2.

TABLE 2 basic Properties of municipal sludge compost Material

pH	Water content (%)	Total carbon (%)	Total nitrogen (%)	C/N
					7.3	64.7	60.2	3.1	19:1

The composite high-temperature microbial inoculum in the embodiment 1 comprises the following components in percentage by mass: 5 percent of municipal sludge: 95 percent of the composite high-temperature microbial inoculum and the municipal sludge are mixed. Adjusting the water content to about 60% by using rice hulls, stacking and fermenting, wherein the compost is subjected to intermittent aeration (aeration is carried out for 8 hours every day, and aeration is not carried out for 16 hours), and turning the compost once every 7 days. A blank control is set, and the compound high-temperature microbial inoculum is not added in the control group.

Sampling is carried out on days 0, 3, 5, 7, 9, 11, 13, 15, 17, 20, 23, 26, 29, 32, 35 and 38 of the beginning of composting respectively, the yield of free radicals in the composting process is measured (by adopting a conventional detection method in the field), and the change of the content of the micro-plastics before and after the sludge composting is statistically analyzed by means of microscopic observation, Fourier infrared spectrum identification and the like.

The results are shown in FIGS. 1 to 2.

By comparing the free radical yields of the control group and the experimental group in the composting process, it can be found that the hydroxyl free radical yield of the experimental group added with the composite high temperature microbial inoculum in example 1 is much higher than that of the control group in the composting process. In addition, after the compost becomes thoroughly decomposed (45 days after the compost), the content of the micro-plastics in the compost of the experimental group to which the complex high-temperature microbial inoculum of example 1 was added and the content of the micro-plastics in the compost of the control group were decreased to different degrees (fig. 2), wherein the content of the micro-plastics in the compost of the experimental group to which the complex high-temperature microbial inoculum of example 1 was added was 7.3 × 10 of the raw materials of the compost⁴One/kg (dry weight) drops to about 4.0X 10⁴The removal rate of the microplastic is about 45% per kilogram (dry weight), while the removal rate of the microplastic in the compost of the control group is only about 6.8% (the content of the microplastic after the decomposition is about 6.8X 10)⁴One/kg), the removal effect of the micro-plastics of the experimental group added with the composite high-temperature microbial inoculum in the embodiment 1 is far better than that of the control group, which shows that the micro-plastics in the sludge can be effectively removed by the composite high-temperature microbial inoculum in the embodiment.

The inventor further tests the composite high-temperature microbial inoculum in the embodiments 2 and 3 respectively, wherein the removal rate of the composite high-temperature microbial inoculum in the embodiment 2 to the micro-plastic is 43%, and the removal rate of the composite high-temperature microbial inoculum in the embodiment 3 to the micro-plastic is 48%, which are far higher than the removal rate of the micro-plastic of a control group set at the same time. Therefore, it can be fully demonstrated that the composite high-temperature microbial inoculum in the above embodiment can effectively remove the micro-plastics in the sludge.

(2) The composite high-temperature microbial inoculum promotes the polystyrene oxidation degradation effect in the high-temperature compost of chicken manure:

in order to further verify the degradation capability of the composite high-temperature microbial inoculum to the plastics and indicate the degradation mechanism of the composite high-temperature microbial inoculum to the plastics, polystyrene is used as a test sample in the embodiment, and the oxidative degradation effect of the composite high-temperature microbial inoculum to the polystyrene is detected. The control treatment group is not added with the composite high-temperature microbial inoculum

The specific test steps are as follows:

the polystyrene film was cut into 5cm × 5cm pieces to obtain polystyrene plastic sheets. The cut polystyrene plastic sheet, the composite high-temperature microbial inoculum prepared in example 3 and the chicken manure are mixed according to the mass percentage of 1%: 4%: mixing at 95% ratio. Wherein, the basic properties of the chicken manure are detected by adopting the conventional detection method in the field, and the results are shown in table 3.

TABLE 3 basic Properties of Chicken manure compost Material

pH	Water content (%)	Total carbon (%)	Total nitrogen (%)	C/N
					7.6	66.0	52.5	4.2	13:1

The moisture content of the uniformly mixed polystyrene plastic sheet, the composite high-temperature microbial inoculum prepared in example 3 and the chicken manure mixture is adjusted to about 60% by using rice hulls, the mixture is piled and fermented, and the compost is subjected to batch aeration (8 hours of aeration every day and 16 hours of non-aeration) and is turned once every 7 days.

Samples were taken at 0, 1, 3, 5, 7, 9, 11, 15, 17, 20, 23, 26, 29, 35, 38, 40, 44 days from the start of composting to determine the yield of free radicals (using methods conventional in the art) during composting, and statistical analysis was performed by microscopic observation, fourier-infrared spectroscopy, etc. for changes in the morphology and content of polystyrene plastic pieces before and after composting.

The results are shown in FIGS. 3 to 6.

As shown in fig. 3, the yield of hydroxyl radicals generated in the high-temperature composting process of the chicken manure added with the composite high-temperature microbial inoculum prepared in example 3 is obviously higher than that of a control group without the composite high-temperature microbial inoculum. Through Fourier infrared spectrum identification, in the composting group added with the compound high-temperature microbial inoculum, the molecular weight of the polystyrene micro plastic sheet is remarkably reduced, while the molecular weight of the polystyrene micro plastic in the control group is not remarkably reduced (figure 4), and the oxygen-containing functional groups on the surface are increased (figure 5). Further, scanning electron microscope observation was performed on the polystyrene microplastic sheets before and after composting, and it was found that a large amount of iron oxide and microorganisms were attached to the surface of the polystyrene film and that obvious erosion holes were formed (fig. 6). Experimental results show that the composite high-temperature microbial inoculum in the embodiment can generate a large amount of hydroxyl radicals in high-temperature chicken manure compost, destroy hydrophobicity of the surface of a plastic material, and promote oxidative degradation of micro-plastics.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.