Long-acting oxygen release particle, preparation and application thereof, and contaminated soil remediation method

Abstract

The invention belongs to the technical field of soil remediation, and discloses long-acting oxygen release particles, preparation and application thereof and a contaminated soil remediation method. The long-acting oxygen release particles are of a double-layer structure comprising inner-layer particles and outer-layer coatings, the inner-layer particles are mixture particles of calcium peroxide and a first adhesive, and the outer-layer coatings are a mixture of a slightly-soluble water-soluble acid coating material with the thickness of 0.01 mm-5 mm and a second adhesive. The long-acting oxygen release particles can be used for replacing an air inlet and exhaust system of a biological reactor, oxygen needed in the bioremediation process is supplemented, sufficient electron acceptors are provided to strengthen the aerobic metabolism process of microorganisms, and the remediation effect of petroleum-contaminated soil is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil remediation, and more specifically, relates to a long-acting oxygen-releasing particle and its preparation and application as well as a contaminated soil remediation method. Background Art

[0002] Oil is the most indispensable resource in modern industrial production and life. With the continuous progress of human society, the development and utilization of oil resources continue to increase. Environmental pollution accidents such as oil processing, transportation and tank leakage that easily cause soil pollution occur from time to time. At present, the main technologies for remediation of oil-contaminated soil at home and abroad include thermal desorption, chemical oxidation, leaching, bioremediation, gas phase and multiphase extraction. Among them, bioremediation technology has been gradually applied in the remediation of oil-contaminated soil due to its advantages of low cost, small impact on the environment, good treatment effect and no secondary pollution.

[0003] Biopile remediation technology is a widely used ex situ soil bioremediation technology, which refers to the use of artificial reinforcement measures on contaminated soil piles to promote the growth of indigenous or exogenous microorganisms that have the ability to degrade pollutants in the soil, thereby degrading pollutants in the soil. Biopile remediation technology has a good effect on easily biodegradable organic matter such as petroleum-contaminated soil and petroleum hydrocarbons in oil sludge, and the cost is relatively low. In the process of microorganisms degrading organic matter as a carbon source and electron donor, oxygen is required as an electron acceptor. Therefore, the biopile remediation system needs to use the intake system and the exhaust system to inject air, oxygen or ozone to increase the oxygen content in the soil. During the operation of the project, it was found that the power consumption of the intake system and the exhaust system became the main cost expenditure.

[0004] CN106477709A discloses a ferrous activated persulfate slow-release candle for in-situ oxidation and repair of groundwater, which is composed of an oxidant, an activator, a dispersant and a coagulant. The oxidant is persulfate, and the activator is composed of a ferrous ion compound, zero-valent iron powder and high-iron fly ash, and has the self-activation function of ferrous iron and magnet. The invention can be activated by itself after contacting water, and has a controllable sulfate radical slow-release ability. CN114177845A discloses a preparation method of a multifunctional polyvinyl alcohol hydrogel material for water body ecological restoration, which is a functional material that can slowly release oxygen and has a certain effect of adsorbing pollutants. The oxygen-releasing functional material is selected from one or more of calcium peroxide, urea peroxide, sodium perborate, and sodium percarbonate; the enrichment functional material is selected from one or more of granular activated carbon, zeolite, silica gel, and alumina; the catalytic functional material is selected from one or more of iron / carbon, nano iron, zero-valent iron, iron filings, and pyrite. The material has a good oxygen release effect and has a combined effect of adsorbing pollutants, and is pollution-free to the environment. It can be seen that solid oxygen-releasing materials can also replace the air intake and exhaust systems to provide electron acceptors for the aerobic metabolic process of biopile microorganisms.

[0005] Solid oxygen release agents include calcium peroxide, magnesium peroxide and sodium percarbonate. Calcium peroxide has become the most commonly used oxygen release material due to its low price and simple production process. When calcium peroxide meets water, it will react to release oxygen 2CaO 2 +2H 2 O=2Ca(OH) 2 +O 2 ↑, so that the oxygen concentration in the environment increases rapidly, which can meet the needs of aerobic metabolism of microorganisms, but due to the short oxygen release time and lack of continuity, it cannot meet the long-term needs of microorganisms for oxygen during bioremediation. CN112674001A discloses a composite tablet with a slow-release oxygen function, a preparation method and use, with calcium peroxide as an oxygen release agent; polylactic acid particles as an embedding agent, in which calcium peroxide is wrapped; anhydrous calcium chloride as a hygroscopic agent; manganese dioxide as a catalyst. The tablet has the characteristics of being able to effectively control the oxygen release rate of calcium peroxide and spontaneously absorb moisture in humid air. It is placed in the transportation device of fresh crabs, which can solve the problem of decreased vitality or even death of crabs during waterless transportation. Although solid oxygen-releasing materials can provide electron acceptors for the aerobic metabolism of biopile microorganisms, there are still problems such as short oxygen release time and difficulty in regulation, and it is difficult to completely replace the role of the air intake and exhaust system in biopile remediation technology.

[0006] Therefore, it is urgent to propose a long-acting oxygen-releasing particle and its preparation and application as well as a method for remediating contaminated soil. Summary of the invention

[0007] The purpose of the present invention is to address the deficiencies of the prior art and to propose a long-acting oxygen-releasing particle, its preparation and application, and a method for remediating contaminated soil. The long-acting oxygen-releasing particle of the present invention can be used to replace the air intake and exhaust system of the biopile, supplement the oxygen required in the bioremediation process, provide sufficient electron acceptors to strengthen the aerobic metabolism process of microorganisms, and improve the remediation effect of petroleum-contaminated soil.

[0008] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a long-acting oxygen-releasing particle, which is a double-layer structure including inner layer particles and an outer layer coating, wherein the inner layer particles are a mixture of calcium peroxide and a first adhesive, and the outer layer coating is a mixture of a slightly soluble water-soluble acid coating material and a second adhesive with a thickness of 0.01mm-5mm.

[0009] According to the present invention, preferably, the slightly soluble and readily soluble acid coating material is at least one of calcium phosphate, calcium hydrogen phosphate and calcium dihydrogen phosphate.

[0010] According to the present invention, preferably, the first binder and the second binder are each independently at least one of cellulose acetate, chitosan and starch.

[0011] According to the present invention, preferably, based on the total weight of the inner layer particles, the content of calcium peroxide is 80%-99%, and the content of the first binder is 1%-20%.

[0012] According to the present invention, preferably, based on the total weight of the outer coating, the content of the slightly soluble and readily soluble acid coating material is 80%-99%, and the content of the second binder is 1%-20%.

[0013] According to the present invention, preferably, the particle size of the long-acting oxygen-releasing particles is 7-10 mm;

[0014] The thickness of the outer coating is 0.05mm-5mm;

[0015] The particle size of the inner layer particles is 3.5 mm-9.0 mm.

[0016] According to the present invention, preferably, the long-acting oxygen-releasing particles are a mixture of multiple long-acting oxygen-releasing particles with different outer coating thicknesses. The different outer coating thicknesses may be equidistant or not, preferably equidistant. In the present invention, for example, they are all spaced 1mm or 0.5mm apart.

[0017] According to the present invention, preferably, the thickness of the outer coating of the various long-acting oxygen-releasing particles with different outer coating thicknesses are 1 mm, 2 mm, 3 mm, and 4 mm, respectively, and the ratio of the various long-acting oxygen-releasing particles is (0.5-1.5): (0.5-1.5): (0.5-1.5): (0.5-1.5).

[0018] The second aspect of the present invention provides a method for preparing the long-acting oxygen-releasing particles, the method comprising the following steps:

[0019] S1: mixing calcium peroxide and a binder and performing water mist granulation, granulation, sieving, and drying to obtain the inner layer particles;

[0020] S2: mixing the slightly water-soluble and readily soluble acid coating material, the binder and water and stirring until gelatinization to obtain an outer coating mixture slurry;

[0021] S3: Spraying the outer coating mixture slurry onto the inner layer particles, drying and sieving, to obtain the long-acting oxygen-releasing particles.

[0022] According to the present invention, preferably, in step S1, the drying temperature is 100-110°C.

[0023] According to the present invention, preferably, in step S2, the operating conditions for mixing and stirring the slightly soluble water-soluble acid coating material, the binder and water until gelatinization include: a water bath at a temperature of 80-90°C.

[0024] According to the present invention, preferably, in step S3, the drying temperature is 65-75°C.

[0025] The third aspect of the present invention provides the application of the long-acting oxygen-releasing particles in the field of contaminated soil remediation.

[0026] According to the present invention, preferably, the contaminated soil remediation is the biopile method for remediating petroleum contaminated soil.

[0027] A fourth aspect of the present invention provides a method for remediating contaminated soil, the method comprising the following steps:

[0028] (1) crushing and screening the contaminated soil to obtain soil particles;

[0029] (2) uniformly mixing the soil particles, the optional microbial nutrition promoter, the optional composite microbial agent and the long-acting oxygen-releasing particles according to any one of claims 1 to 4 to establish a biopile;

[0030] (3) During the operation and maintenance of the biopile, the pH value of the replenishment water and the oxygen concentration in the biopile are monitored, and the oxygen release rate of the long-acting oxygen-releasing particles is controlled by adjusting the pH value of the replenishment water.

[0031] According to the present invention, preferably, the particle size of the soil particles is less than 2 cm.

[0032] According to the present invention, preferably, the height of the biopile is 80 cm-120 cm.

[0033] The beneficial effects of the technical solution of the present invention are as follows:

[0034] 1. The long-acting oxygen-releasing particles provided by the present invention that can be used for biopile method remediation of petroleum-contaminated soil provide a feasible technical solution for replacing the air extraction and air intake systems in biopile technology.

[0035] 2. During the construction of the biopile, the long-acting oxygen-releasing particles of the present invention are uniformly mixed with the microbial nutrition promoter and the composite microbial agent in the contaminated soil. This will not increase the amount of engineering work, but also save the need for pre-buried air intake and exhaust pipelines and laying links. There is no additional electricity consumption during operation, which greatly reduces the cost of biopile construction and operation and maintenance costs.

[0036] 3. The present invention can control the total oxygen release time and the oxygen release amount in different time periods by controlling the thickness and ratio of the outer coating layer of the long-acting oxygen-releasing particles, and the total oxygen release time can be up to 24 months. For example, the long-acting oxygen-releasing particles with outer coating thicknesses of 1mm, 2mm, 3mm, and 4mm can be mixed in a ratio of 1:1:1:1 to ensure uniform oxygen release during the entire oxygen release cycle.

[0037] 4. The oxygen release rate of the contaminated soil remediation method of the present invention is stable, and the oxygen release rate can be adjusted by controlling the pH value of the water replenishment. This is because the present invention uses a material that is slightly soluble in water and easily soluble in acid as the coating material (calcium hydrogen phosphate). Therefore, when it is found that the oxygen concentration in the biopile is lower than the design concentration, the water replenishment pH value can be temporarily adjusted to be slightly lower than 7 to accelerate the oxygen release rate. Similarly, when it is found that the oxygen concentration in the biopile is higher than the design concentration, the water replenishment pH value can be temporarily adjusted to be slightly higher than 7 to reduce the oxygen release rate.

[0038] 5. The oxygen-releasing process of calcium peroxide in the long-acting oxygen-releasing particles of the present invention releases heat, which is beneficial to improving the activity of microorganisms and accelerating the metabolism of pollutants.

[0039] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0041] Figure 1 A schematic cross-sectional view of a long-acting oxygen-releasing particle provided by the present invention is shown.

[0042] Figure 2 A cross-sectional schematic diagram of a biopile established by a contaminated soil remediation method provided in Example 8 of the present invention is shown.

[0043] The following are the descriptions of the reference numerals:

[0044] 1-Inner layer of granules; 2-Outer layer of coating; 3-Biopile. DETAILED DESCRIPTION

[0045] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0046] Example 1

[0047] This embodiment provides a method for preparing long-acting oxygen-releasing particles, the preparation method comprising the following steps:

[0048] S1: 8kg of calcium peroxide and 2kg of adhesive starch are mixed to prepare 10kg of granular inner layer powder; the disc inclination angle of the disc granulator is adjusted to 60°, the speed is adjusted to 30r / min, and the temperature is adjusted to 40°C, 1kg of the inner layer granular powder is added, and the particles are quickly moistened with water mist to form small particles with a particle size of about 0.5mm. After the granulation is completed, the remaining 9kg of the inner layer granular powder is put into a vibrating feeder, and the powder is added at a uniform speed of 100g / min. The water mist spray gun is adjusted to 30cm from the highest falling point of the powder in the disc, and the falling reflux material is sprayed. The spraying water volume is adjusted to 15mL / min, and the particles are sieved to obtain inner layer particles with a particle size of 4mm. The particles are placed in an oven at 105°C for drying, and the moisture is removed and cooled for use;

[0049] S2: 19.8 kg of calcium hydrogen phosphate powder and 0.2 kg of cellulose acetate are mixed evenly to prepare 20 kg of outer coating powder; 20 kg of outer coating powder is mixed with water and stirred at 80° C. in a water bath for 20 min until gelatinization is obtained to obtain an outer coating mixture slurry;

[0050] S3: Start the fluidized bed coating machine, adjust the inlet temperature to 100°C, and the inlet air volume to 2000m 3 / h, preheat the inner layer particles in step S1 for 10 minutes, start the coating liquid feed pump, adjust the nozzle pressure to 0.3MPa, and start spraying the outer coating mixture slurry on the inner layer particles. After spraying, adjust the inlet temperature to 70°C and dry for 30 minutes to obtain the long-acting oxygen-releasing particles, and the thickness of the outer coating is 4mm.

[0051] Example 2

[0052] This embodiment provides a method for preparing long-acting oxygen-releasing particles. The difference between this embodiment and embodiment 1 is only that:

[0053] In step S1, 9.9 kg of calcium peroxide and 0.1 kg of cellulose acetate as a binder are mixed to prepare 10 kg of inner layer powder of the granules, and finally the inner layer granules with a particle size of 8.9 mm are obtained;

[0054] In step S2, 1.6 kg of calcium hydrogen phosphate powder and 0.4 kg of chitosan are mixed evenly to prepare 2 kg of outer coating powder; 2 kg of outer coating powder is mixed with water and stirred in a water bath at 80° C. for 20 min until gelatinization is obtained to obtain an outer coating mixture slurry;

[0055] The thickness of the outer coating of the long-acting oxygen-releasing particles is 0.1 mm.

[0056] Example 3

[0057] This embodiment provides a method for preparing long-acting oxygen-releasing particles. The difference between this embodiment and embodiment 1 is only that:

[0058] In step S1, 9 kg of calcium peroxide and 1 kg of chitosan adhesive are mixed to prepare 10 kg of granular inner layer powder, and finally inner layer granules with a particle size of 6 mm are obtained;

[0059] In step S2, 4.2 kg of calcium hydrogen phosphate powder and 0.8 kg of starch are mixed evenly to prepare 5 kg of outer coating powder; 8 kg of outer coating powder is mixed with water and stirred in a water bath at 80° C. for 20 min until gelatinization to obtain an outer coating mixture slurry;

[0060] The thickness of the outer coating of the long-acting oxygen-releasing particles is 3 mm.

[0061] Example 4

[0062] This embodiment provides a method for preparing long-acting oxygen-releasing particles. The difference between this embodiment and embodiment 1 is only that:

[0063] In step S1, 8.8 kg of calcium peroxide and 1.2 kg of cellulose acetate as a binder are mixed to prepare 10 kg of inner layer powder of the granules, and finally the inner layer granules with a particle size of 6 mm are obtained;

[0064] In step S2, 2.5 kg of calcium phosphate powder and 0.5 kg of chitosan are mixed evenly to prepare 3 kg of outer coating powder; 2 kg of outer coating powder is mixed with water and stirred in a water bath at 80° C. for 20 min until gelatinization is obtained to obtain an outer coating mixture slurry;

[0065] The thickness of the outer coating of the long-acting oxygen-releasing particles is 2 mm.

[0066] Example 5

[0067] This embodiment provides a method for preparing long-acting oxygen-releasing particles. The difference between this embodiment and embodiment 1 is only that:

[0068] In step S1, 9.5 kg of calcium peroxide and 0.5 kg of cellulose acetate as a binder are mixed to prepare 10 kg of inner layer powder of the granules, and finally the inner layer granules with a particle size of 8 mm are obtained;

[0069] In step S2, 2.8 kg of calcium dihydrogen phosphate powder and 0.2 kg of starch are mixed evenly to prepare 3 kg of outer coating powder; 2 kg of outer coating powder is mixed with water and stirred in a water bath at 80° C. for 20 min until gelatinization is obtained to obtain an outer coating mixture slurry;

[0070] The thickness of the outer coating of the long-acting oxygen-releasing particles is 1 mm.

[0071] Example 6

[0072] This embodiment provides a method for preparing long-acting oxygen-releasing particles. The difference between this embodiment and embodiment 1 is only that:

[0073] In step S1, 8.5 kg of calcium peroxide and 1.5 kg of chitosan adhesive are mixed to prepare 10 kg of granular inner layer powder, and finally inner layer granules with a particle size of 4 mm are obtained;

[0074] In step S2, 11 kg of calcium dihydrogen phosphate powder and 1 kg of cellulose acetate are mixed evenly to prepare 12 kg of outer coating powder; 2 kg of outer coating powder is mixed with water and stirred at 80° C. in a water bath for 20 min until gelatinization is obtained to obtain an outer coating mixture slurry;

[0075] The thickness of the outer coating of the long-acting oxygen-releasing particles is 5 mm.

[0076] Example 7

[0077] This embodiment provides a method for remediating petroleum-contaminated soil by biopile method, the method comprising the following steps:

[0078] (1) crushing and sieving the contaminated soil to obtain soil particles with a particle size of less than 2 cm;

[0079] (2) mixing the long-acting oxygen-releasing particles of Examples 1, 2, 3, and 4 in a mass ratio of 1:1:1:1 to obtain long-acting oxygen-releasing mixed particles;

[0080] (3) mixing the soil particles and the long-acting oxygen-releasing mixed particles of step (2) to form a biopile with a height of 90 cm to 110 cm;

[0081] (4) During the operation and maintenance of the biopile, the pH value of the replenished water and the oxygen concentration in the biopile are monitored. The monitoring in this embodiment found that the oxygen content concentration in the soil air in the biopile was always greater than 20%, and the total oxygen release time of the long-acting oxygen-releasing particles could be up to 24 months.

[0082] Example 8

[0083] This embodiment provides a method for remediating petroleum-contaminated soil by biopile method, the method comprising the following steps:

[0084] (1) crushing and sieving the contaminated soil to obtain soil particles with a particle size of less than 2 cm;

[0085] (2) The long-acting oxygen-releasing particles of Examples 1, 2, 3, and 4 were uniformly mixed in a mass ratio of 0.5:1:1:1.5 to obtain long-acting oxygen-releasing mixed particles;

[0086] (3) The soil particles, microbial nutrient promoter (any commercially available), composite microbial agent (any commercially available) and the long-acting oxygen-releasing mixed particles of the above step (2) are mixed evenly to establish a biopile with a height of 90 cm-110 cm; (4) During the operation and maintenance of the biopile, the pH value of the water replenishment and the oxygen concentration in the biopile are monitored. In this embodiment, it is found that the oxygen concentration in the biopile is lower than the design concentration (10%). Therefore, in this embodiment, the pH value of the water replenishment is temporarily adjusted to be slightly lower than 7, so that the oxygen in the soil air is increased to more than 20% and then normal water replenishment is restored; In this embodiment, it is also found that the oxygen concentration in the biopile is higher than the design concentration. Therefore, in this embodiment, the pH value of the water replenishment is temporarily adjusted to be slightly higher than 7 to reduce the oxygen release rate.

[0087] The total oxygen release time of the long-acting oxygen-releasing mixed particles in step (2) above can be up to 24 months.

[0088] Comparative Example 1

[0089] The only difference between this embodiment and embodiment 7 is that no long-acting oxygen-releasing particles are added during the biopile construction process, and monitoring shows that the oxygen content concentration in the soil air in the biopile is less than 15% after 7 days.

[0090] By comparing the oxygen content monitoring results of Example 7 with those of Comparative Example 1, it can be seen that the long-acting oxygen-releasing particles used in the present invention can effectively replenish the oxygen content in the biopile, and the oxygen release process is stable, and the total oxygen release time can be up to 24 months.

[0091] Comparative Example 2

[0092] The only difference between this embodiment and embodiment 8 is that no long-acting oxygen-releasing particles are added during the biopile construction process, and monitoring shows that the oxygen content concentration in the soil air in the biopile is less than 15% after 3 days.

[0093] By comparing the oxygen content monitoring results of Example 8 with those of Comparative Example 2, it can be seen that the long-acting oxygen-releasing particles used in the present invention can effectively supplement the oxygen required for the microbial degradation of organic pollutants in the biopile, and the oxygen release process is smooth, and the total oxygen release time can be up to 24 months.

[0094] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A long-acting oxygen-releasing granule, characterized in that: The long-acting oxygen-releasing particles are a double-layer structure including inner layer particles and an outer layer coating, wherein the inner layer particles are a mixture of calcium peroxide and a first adhesive, and the outer layer coating is a mixture of a slightly water-soluble and easily acid-soluble coating material with a thickness of 0.01 mm to 5 mm and a second adhesive.

2. The long-acting oxygen-releasing granules according to claim 1, wherein: The slightly water-soluble and readily acid-soluble coating material is at least one of calcium phosphate, calcium hydrogen phosphate and calcium dihydrogen phosphate; The first binder and the second binder are each independently at least one of cellulose acetate, chitosan and starch; Based on the total weight of the inner layer particles, the content of calcium peroxide is 80%-99%, and the content of the first binder is 1%-20%; Based on the total weight of the outer coating, the content of the slightly soluble and readily soluble acid coating material is 80%-99%, and the content of the second adhesive is 1%-20%.

3. The long-acting oxygen-releasing granules according to claim 1, wherein: The particle size of the long-acting oxygen-releasing particles is 7-10 mm; The thickness of the outer coating is 0.05mm-5mm; The particle size of the inner layer particles is 3.5 mm-9.0 mm.

4. The long-acting oxygen-releasing granules according to claim 1, wherein: The long-acting oxygen-releasing particles are a mixture of a plurality of long-acting oxygen-releasing particles with different outer coating thicknesses, and the different outer coating thicknesses are preferably arranged equidistantly.

5. The long-acting oxygen-releasing granules according to claim 4, wherein: The thicknesses of the outer coatings of the various long-acting oxygen-releasing particles with different outer coating thicknesses are 1 mm, 2 mm, 3 mm, and 4 mm, respectively, and the ratio of the various long-acting oxygen-releasing particles is (0.5-1.5): (0.5-1.5): (0.5-1.5): (0.5-1.5).

6. The method for preparing the long-acting oxygen-releasing particles according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: S1: mixing calcium peroxide and a binder and performing water mist granulation, granulation, sieving, and drying to obtain the inner layer particles; S2: mixing the slightly water-soluble and readily soluble acid coating material, the binder and water and stirring until gelatinization to obtain an outer coating mixture slurry; S3: spraying the outer coating mixture slurry onto the inner layer particles, drying and sieving to obtain the long-acting oxygen-releasing particles; Preferably, in step S1, the drying temperature is 100-110°C; Preferably, in step S2, the slightly water-soluble and readily soluble acid coating material, the binder and water are mixed and stirred until gelatinization, and the operating conditions include: a water bath at a temperature of 80-90°C; Preferably, in step S3, the drying temperature is 65-75°C.

7. Use of the long-acting oxygen-releasing particles described in any one of claims 1 to 5 in the field of contaminated soil remediation.

8. The use according to claim 7, wherein: The contaminated soil remediation is a biopile method for remediating petroleum contaminated soil.

9. A method for remediating contaminated soil, characterized in that: The method comprises the following steps: (1) crushing and screening the contaminated soil to obtain soil particles; (2) uniformly mixing the soil particles, the optional microbial nutrition promoter, the optional composite microbial agent and the long-acting oxygen-releasing particles according to any one of claims 1 to 4 to establish a biopile; (3) During the operation and maintenance of the biopile, the pH value of the replenishment water and the oxygen concentration in the biopile are monitored, and the oxygen release rate of the long-acting oxygen-releasing particles is controlled by adjusting the pH value of the replenishment water.

10. The method for remediating contaminated soil according to claim 9, wherein: The particle size of the soil particles is less than 2 cm; The height of the biopile is 80cm-120cm.

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