Self-heating soil petroleum hydrocarbon degradation treatment agent and use method thereof

Abstract

The invention belongs to the technical field of oil field oil-containing polluted soil treatment, and relates to a self-heating soil petroleum hydrocarbon degradation treatment agent which comprises denitrifying bacteria, a microbial agent, a microbial degradation nutrient solution, nitrate, ammonium salt and expanded vermiculite. The adding amount of the denitrifying bacteria is 1%-3% of the mass of the petroleum hydrocarbon polluted soil; the microbial agent is petroleum hydrocarbon degrading bacteria, and the addition amount of the microbial agent is 1-3% of the mass of the petroleum hydrocarbon polluted soil; the mass ratio of the sodium nitrate to the denitrifying bacteria is (0.5-0.7): 1; the mass ratio of ammonium chloride to sodium nitrate is (1-1.5): 1; the adding amount of the expanded vermiculite is 2%-3% of the mass of the petroleum hydrocarbon contaminated soil. The invention further discloses a using method of the microbial agent, the denitrifying bacteria serve as a heat production initiator, nitrate is slowly decomposed into nitrite, the whole heat production reaction is changed into a controllable reaction by controlling slow production of reactants of the heat production reaction, and smooth proceeding of microbial treatment of the oil-containing contaminated soil is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of oil-contaminated soil treatment in oil fields, and in particular relates to a self-heating soil petroleum hydrocarbon degradation treatment agent and a use method thereof. Background Art

[0002] The oil-contaminated soil produced by oil leakage from wellheads and pipelines during the oil extraction process has the characteristics of large contamination area, complex composition, and high treatment cost. In addition, the non-volatile components in the oil will destroy the soil structure, reduce soil fertility, affect the survival of microorganisms in the soil and the stability of the ecosystem. If it is landfilled or piled on the spot without treatment, it will not only waste oil resources, but also cause environmental pollution.

[0003] Microbial treatment technology is currently the most promising technology for treating oil-contaminated soil at home and abroad. This technology uses microorganisms to degrade and mineralize oil-containing sludge, and ultimately convert it into inorganic substances such as water and carbon dioxide. It has the advantages of low treatment cost, simple operation, large-scale restoration of oil-contaminated soil, and no secondary pollution.

[0004] However, during the field trials of this technology, it was found that: on the one hand, microorganisms need to be between 35°C and 60°C to fully function, and the temperature conditions required for microbial treatment cannot be met under normal conditions; on the other hand, low-temperature areas will experience permafrost due to low temperatures, and low temperatures will also reduce the degradation activity of microorganisms, which is not conducive to the promotion and application of this technology.

[0005] Patent document with publication number CN 106350050 B discloses a reaction control method based on a self-heating system of sodium nitrite / ammonium chloride and its application. The sodium nitrite and ammonium chloride are triggered and controlled to release heat rapidly in the target layer by a composite catalyst and a catalytic activity inhibitor. However, in the process of microbial treatment of oil-contaminated soil, the heat released by the violent reaction is not conducive to the occurrence of the microbial degradation process. The temperature is too high in an instant, which easily leads to the death of the microorganisms or the loss of degradation activity. In addition, in the process of microbial degradation of oil-contaminated soil, the first prerequisite is not to introduce foreign substances. The initiator in this patent is a polybasic organic acid, and the catalytic activity inhibitor is a polybasic organic base. On the one hand, the effect of the introduced foreign substances on the microbial degradation effect is unknown, and the addition of organic bases easily leads to soil compaction, which is not conducive to later soil restoration and vegetation growth.

[0006] Patent document with publication number CN 113355076 A discloses a heat-generating material for heavy oil and its application. Although phosphoric acid solution is used as the initiator, and although the phosphoric acid solution can provide nutrients for microorganisms, after the initiator is added, ammonium salt, nitrite, carbon donor and initiator undergo redox reaction in an acidic environment, generating a large amount of heat. The instantaneous increase in temperature is not conducive to the microbial degradation reaction. Summary of the invention

[0007] The purpose of the present invention is to provide a self-heating soil petroleum hydrocarbon degradation treatment agent and a method of using the same, which solves the problem of poor microbial degradation activity and excessively intense degradation reactions caused by low winter temperatures during the treatment of oily sludge.

[0008] The present invention is achieved through the following technical solutions:

[0009] A self-heating soil petroleum hydrocarbon degradation treatment agent, comprising denitrifying bacteria, microbial agents, microbial degradation nutrient solution, nitrate, ammonium salt and expanded vermiculite;

[0010] The dosage of the denitrifying bacteria is 1%-3% of the mass of the petroleum hydrocarbon-contaminated soil;

[0011] The microbial agent is a petroleum hydrocarbon degrading bacterium, and the dosage is 1%-3% of the mass of the petroleum hydrocarbon contaminated soil;

[0012] The mass ratio of sodium nitrate to denitrifying bacteria is 0.5-0.7:1;

[0013] The mass ratio of ammonium chloride to sodium nitrate is 1-1.5:1;

[0014] The dosage of the expanded vermiculite is 2%-3% of the mass of the petroleum hydrocarbon contaminated soil.

[0015] Furthermore, the main strain of denitrifying bacteria is of the genus Pseudomonas alcaligenes.

[0016] Furthermore, the main strains of the petroleum hydrocarbon degrading bacteria are Bacillus pumilus, Pseudomonas monteri or Acinetobacter luffii.

[0017] Furthermore, the dosage of the microbial degradation nutrient solution is 1% of the mass of the petroleum hydrocarbon contaminated soil.

[0018] Furthermore, the nitrate is sodium nitrate.

[0019] Furthermore, the ammonium salt is ammonium chloride.

[0020] Furthermore, the denitrifying bacteria are solid brown powder, and the microbial agent is a solid agent.

[0021] The present invention also discloses a method for using a self-heating soil petroleum hydrocarbon degradation treatment agent, comprising the following steps:

[0022] (1) mixing oil-contaminated soil, denitrifying bacteria, microbial agents, sodium nitrate, ammonium chloride and expanded vermiculite, and composting after being fully mixed by an on-site mixer;

[0023] (2) Mix the microbial degradation nutrient solution with water and dilute it, then spray it onto the pile to provide nutrients for the microbial agents and denitrifying bacteria in the pile, and cover the surface with a plastic film to keep the pile moist;

[0024] (3) Depending on the oil content, after 3-7 days of composting, denitrifying bacteria convert sodium nitrate into sodium nitrite, and the sodium nitrite reacts with ammonium chloride to generate heat. The heat is kept for 7-9 days to obtain the treated oil-contaminated soil.

[0025] Furthermore, in step (1), the optimal stacking height is 70 cm.

[0026] Furthermore, in step (2), the microbial degradation nutrient solution and water are mixed in a ratio of 1:5.

[0027] Compared with the prior art, the present invention has the following beneficial technical effects:

[0028] The present invention discloses a self-heating soil petroleum hydrocarbon degradation treatment agent, which includes denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite. Through the heat release of soil microbial fermentation, denitrifying bacteria convert sodium nitrate into sodium nitrite to generate initial heat, which triggers the subsequent sodium nitrite and ammonium chloride reaction to continue. The slow microbial fermentation reaction provides heat for the heat-producing reaction, the heat generated by the chemical reaction provides heat for the microbial degradation, the microbial degradation nutrient solution provides nutrients for the microbial agents and denitrifying bacteria in the pile, and the expanded vermiculite has a good heat preservation effect, which can preserve this heat for 7-9 days. The present invention uses denitrifying bacteria as a heat-producing initiator to slowly decompose nitrate into nitrite, and controls the slow generation of the reactants of the heat-producing reaction, so that the entire heat-producing reaction becomes a controllable reaction, thereby ensuring the smooth progress of microbial treatment of oil-contaminated soil.

[0029] The invention discloses a method for using a self-heating soil petroleum hydrocarbon degradation treatment agent. Denitrifying bacteria, microbial agents, sodium nitrate, ammonium chloride and expanded vermiculite are first added to the oil-contaminated soil. At the beginning, the microorganisms can degrade organic matter in the oil-contaminated soil through trace elements and nutrients contained in the soil to provide energy for their own survival. In the subsequent process, insufficient trace elements and nutrients in the soil will affect the degradation effect of the microorganisms. Therefore, it is necessary to add microbial degradation nutrient solution after a period of reaction, that is, after composting, to supplement the microorganisms with a certain amount of nutrient solution, which is conducive to the growth of the microorganisms and the continuous progress of the denitrification reaction. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present invention clearer, the following is further described in detail with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments.

[0031] The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents a selected embodiment of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the protection scope of the present invention.

[0032] It should be noted that the terms "comprises", "includes" or any other variations are intended to cover non-exclusive inclusion, such that a process, element, method, article or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed.

[0033] The invention discloses a self-heating soil petroleum hydrocarbon degradation treatment agent, which comprises denitrifying bacteria, microbial agents, microbial degradation nutrient solution, nitrate, ammonium salt and expanded vermiculite;

[0034] The dosage of the denitrifying bacteria is 1%-3% of the mass of the petroleum hydrocarbon-contaminated soil; the main strain of the denitrifying bacteria is Pseudomonas alcaligenes;

[0035] The microbial agent is a petroleum hydrocarbon degrading bacterium, and the dosage is 1%-3% of the mass of the petroleum hydrocarbon contaminated soil; the main strains of the petroleum hydrocarbon degrading bacteria are Bacillus pumilus, Pseudomonas monteridium or Acinetobacter luffii;

[0036] The mass ratio of sodium nitrate to denitrifying bacteria is 0.5-0.7:1;

[0037] The mass ratio of ammonium chloride to sodium nitrate is 1-1.5:1;

[0038] The dosage of the expanded vermiculite is 2%-3% of the mass of the petroleum hydrocarbon contaminated soil.

[0039] The microbial degradation nutrient solution of the invention is a mixture of corn steep liquor, peptone and Tween 80.

[0040] The denitrifying bacteria are solid brown powder, and the microbial agent is a solid agent.

[0041] The self-heating soil petroleum hydrocarbon degradation treatment agent is used in the actual application of treating oil-contaminated soil. The self-heating soil petroleum hydrocarbon degradation treatment agent is added to the oil-contaminated soil in proportion, the soil temperature and oil content changes are regularly monitored, and the application effect of the treatment agent is analyzed.

[0042] According to field application experience, denitrifying bacteria can convert sodium nitrate into sodium nitrite 3-7 days after composting. It can also be determined by detecting nitrite ions in the soil, but doing so on site is costly.

[0043] The features and performances of the present invention are further described in detail below in conjunction with the embodiments.

[0044] Example 1

[0045] This embodiment provides a self-heating soil petroleum hydrocarbon degradation treatment agent, which includes denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite.

[0046] Specifically, the following steps are included: Taking the treatment of 1 ton of contaminated soil with an oil content of 4.8% as an example, the initial temperature of the oil sludge is 4°C.

[0047] (1) 1 ton of contaminated soil with an oil content of less than 5%, 10 kg of denitrifying bacteria, 10 kg of petroleum hydrocarbon degrading bacteria, 5 kg of sodium nitrate, 5 kg of ammonium chloride and 20 kg of expanded vermiculite were mixed and fully mixed in an on-site mixer for composting. The optimal stacking height was 70 cm.

[0048] (2) Mix the microbial degradation nutrient solution with water in a ratio of 1:5 and dilute it, then spray it onto the pile, and cover the surface with a plastic film to maintain a certain humidity;

[0049] (3) After 7 days of composting, the temperature of the compost was measured to be 25°C, a temperature increase of 5.25 times; the oil content in the soil dropped from 4.8% to 1.9%, an increase of 60.42%.

[0050] Example 2

[0051] This embodiment provides a self-heating soil petroleum hydrocarbon degradation treatment agent, which includes denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite.

[0052] Specifically, the following steps are included: Taking the treatment of 1 ton of contaminated soil with an oil content of 4.8% as an example, the initial temperature of the oil sludge is 4°C.

[0053] (1) 1 ton of contaminated soil with an oil content of less than 5%, 10 kg of denitrifying bacteria, 10 kg of petroleum hydrocarbon degrading bacteria, 5 kg of sodium nitrate, 6 kg of ammonium chloride and 20 kg of expanded vermiculite were mixed and composted after being fully mixed in an on-site mixer. The optimal stacking height was 70 cm.

[0054] (2) Mix the microbial degradation nutrient solution with water in a ratio of 1:5 and dilute it, then spray it onto the pile, and cover the surface with a plastic film to maintain a certain humidity;

[0055] (3) It was found that after 7 days of composting, the temperature of the compost was measured to be 30°C, a temperature increase of 6.5 times, and the oil content in the soil decreased from 4.8% to 1.6%, an increase of 66.67%.

[0056] Embodiment 3:

[0057] This embodiment provides a self-heating soil petroleum hydrocarbon degradation treatment agent, which includes denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite.

[0058] Specifically, the following steps are included: Taking the treatment of 1 ton of contaminated soil with an oil content of 4.8% as an example, the initial temperature of the oil sludge is 4°C.

[0059] (1) 1 ton of contaminated soil with an oil content of less than 5%, 10 kg of denitrifying bacteria, 10 kg of petroleum hydrocarbon degrading bacteria, 5 kg of sodium nitrate, 7.5 kg of ammonium chloride and 20 kg of expanded vermiculite were mixed and composted after being fully mixed in an on-site mixer. The optimal stacking height was 70 cm.

[0060] (2) Mix the microbial degradation nutrient solution with water in a ratio of 1:5 and dilute it, then spray it onto the pile, and cover the surface with a plastic film to maintain a certain humidity;

[0061] (3) It was found that after 7 days of composting, the temperature of the compost was measured to be 38°C, an increase of 8.5 times, and the oil content in the soil decreased from 4.8% to 1.3%, an increase of 72.9%.

[0062] Example 4

[0063] This embodiment provides a self-heating soil petroleum hydrocarbon degradation treatment agent, which includes denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite.

[0064] Specifically, the following steps are included: Taking the treatment of 1 ton of contaminated soil with an oil content of 4.8% as an example, the initial temperature of the oil sludge is 4°C.

[0065] (1) 1 ton of contaminated soil with an oil content of less than 5%, 10 kg of denitrifying bacteria, 10 kg of petroleum hydrocarbon degrading bacteria, 6 kg of sodium nitrate, 9 kg of ammonium chloride and 20 kg of expanded vermiculite were mixed and composted after being fully mixed in an on-site mixer. The optimal stacking height was 70 cm.

[0066] (2) Mix the microbial degradation nutrient solution with water in a ratio of 1:5 and dilute it, then spray it onto the pile, and cover the surface with a plastic film to maintain a certain humidity;

[0067] (3) It was found that after 7 days of composting, the temperature of the compost pile was measured to be 42°C, a temperature increase of 9.5 times; the oil content in the soil decreased from 4.8% to 0.86%, an increase of 82.1%.

[0068] Example 5

[0069] This embodiment provides a self-heating soil petroleum hydrocarbon degradation treatment agent, which includes denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite. Specifically, the following steps are included: Taking the treatment of 1 ton of contaminated soil with an oil content of 4.8% as an example, the initial temperature of the oil sludge is 4°C.

[0070] (1) 1 ton of contaminated soil with an oil content of less than 5%, 10 kg of denitrifying bacteria, 10 kg of petroleum hydrocarbon degrading bacteria, 7 kg of sodium nitrate, 10.5 kg of ammonium chloride and 20 kg of expanded vermiculite were mixed and composted after being fully mixed in an on-site mixer. The optimal stacking height was 70 cm.

[0071] (2) Mix the microbial degradation nutrient solution with water in a ratio of 1:5 and dilute it, then spray it onto the pile, and cover the surface with a plastic film to maintain a certain humidity;

[0072] (3) It was found that after 7 days of composting, the temperature of the compost pile was measured to be 35°C, a temperature increase of 7.75 times; the oil content in the soil dropped from 4.8% to 1%, an increase of 79.2%.

[0073] Table 1

[0074] Temperature increase (times) Example 1 5.25 Example 2 6.5 Example 3 8.5 Example 4 9.5 Example 5 7.75

[0075] As shown in Table 1, it can be seen from the comparison of Examples 1 to 5 that for oil-contaminated soil with an oil content of less than 5%, under the action of the self-heating soil petroleum hydrocarbon degradation treatment agent in this embodiment, considering the on-site treatment cost issue, the optimal addition ratio of sodium nitrate is 60% of the mass of denitrifying bacteria, and the optimal addition amount of ammonium chloride is 150% of the mass of sodium nitrate.

[0076] Example 6

[0077] This embodiment provides a self-heating soil petroleum hydrocarbon degradation treatment agent, which includes denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite.

[0078] Specifically, the following steps are included: taking the treatment of 1 ton of contaminated soil with an oil content of about 11.25% as an example, the initial temperature of the oil sludge is 4°C.

[0079] (1) 1 ton of contaminated soil with an oil content of about 11.25%, 20 kg of denitrifying bacteria, 10 kg of petroleum hydrocarbon degrading bacteria, 12 kg of sodium nitrate, 18 kg of ammonium chloride and 20 kg of expanded vermiculite were mixed and composted after being fully mixed in an on-site mixer. The optimal stacking height was 70 cm.

[0080] (2) Mix the microbial degradation nutrient solution with water in a ratio of 1:5 and dilute it, then spray it onto the pile, and cover the surface with a plastic film to maintain a certain humidity;

[0081] (3) It was found that after 5 days of composting, the temperature of the compost pile was measured to be 46°C, a temperature increase of 10.5 times; the oil content in the soil decreased from 11.25% to 3.89%, an increase of 65.4%.

[0082] Example 7

[0083] This embodiment provides a self-heating soil petroleum hydrocarbon degradation treatment agent, which includes denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite.

[0084] Specifically, the following steps are included: Taking the treatment of 1 ton of contaminated soil with an oil content of 11.25% as an example, the initial temperature of the oil sludge is 4°C.

[0085] (1) 1 ton of contaminated soil with an oil content between 5% and 10%, 20 kg of denitrifying bacteria, 15 kg of petroleum hydrocarbon degrading bacteria, 12 kg of sodium nitrate, 18 kg of ammonium chloride and 20 kg of expanded vermiculite were mixed and fully mixed in an on-site mixer for composting, and the optimal stacking height was 70 cm;

[0086] (2) Mix the microbial degradation nutrient solution with water in a ratio of 1:5 and dilute it, then spray it onto the pile, and cover the surface with a plastic film to maintain a certain humidity;

[0087] (3) It was found that after 5 days of composting, the temperature of the compost pile was measured to be 48°C, an increase of 11 times; the oil content in the soil dropped from 11.25% to 3.35%, an increase of 70.2%.

[0088] Example 8

[0089] This embodiment provides a self-heating soil petroleum hydrocarbon degradation treatment agent, which includes denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite.

[0090] Specifically, the following steps are included: Taking the treatment of 1 ton of contaminated soil with an oil content of 11.25% as an example, the initial temperature of the oil sludge is 2°C.

[0091] (1) 1 ton of contaminated soil with an oil content of 5% to 10%, 20 kg of denitrifying bacteria, 20 kg of petroleum hydrocarbon degrading bacteria, 12 kg of sodium nitrate, 18 kg of ammonium chloride and 20 kg of expanded vermiculite were mixed and fully mixed in an on-site mixer for composting, and the optimal stacking height was 70 cm;

[0092] (2) Mix the microbial degradation nutrient solution with water in a ratio of 1:5 and dilute it, then spray it onto the pile, and cover the surface with a plastic film to maintain a certain humidity;

[0093] (3) It was found that after 5 days of composting, the temperature of the compost was measured to be 45°C, a temperature increase of 10.25 times; the oil content in the soil decreased from 11.25% to 2.75%, an increase of 75.6%.

[0094] Example 9

[0095] This embodiment provides a self-heating soil petroleum hydrocarbon degradation treatment agent, which includes denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite. Specifically, the following steps are included: Taking the treatment of 1 ton of contaminated soil with an oil content of 11.25% as an example, the initial temperature of the oil sludge is 2°C.

[0096] (1) 1 ton of contaminated soil with an oil content of 5% to 10%, 20 kg of denitrifying bacteria, 30 kg of petroleum hydrocarbon degrading bacteria, 12 kg of sodium nitrate, 18 kg of ammonium chloride and 20 kg of expanded vermiculite were mixed and fully mixed in an on-site mixer for composting, and the optimal stacking height was 70 cm;

[0097] (2) Mix the microbial degradation nutrient solution with water in a ratio of 1:5 and dilute it, then spray it onto the pile, and cover the surface with a plastic film to maintain a certain humidity;

[0098] (3) It was found that after 5 days of composting, the temperature of the compost pile was measured to be 51.2°C, an increase of 11.8 times; the oil content in the soil dropped from 11.25% to 1.8%, an increase of 84%.

[0099] Embodiment 10:

[0100] This embodiment provides a self-heating soil petroleum hydrocarbon degradation treatment agent, which includes denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite. Specifically, the following steps are included: Taking the treatment of 1 ton of contaminated soil with an oil content of 11.25% as an example, the initial temperature of the oil sludge is 2°C.

[0101] (1) 1 ton of contaminated soil with an oil content between 5% and 10%, 30 kg of denitrifying bacteria, 20 kg of petroleum hydrocarbon degrading bacteria, 12 kg of sodium nitrate, 18 kg of ammonium chloride and 20 kg of expanded vermiculite were mixed and composted after being fully mixed in an on-site mixer, and the optimal stacking height was 70 cm;

[0102] (2) Mix the microbial degradation nutrient solution with water in a ratio of 1:5 and dilute it, then spray it onto the pile, and cover the surface with a plastic film to maintain a certain humidity;

[0103] (3) It was found that after 5 days of composting, the temperature of the compost pile was measured to be 52°C, a temperature increase of 12 times; the oil content in the soil decreased from 11.25% to 2.19%, an increase of 80.5%.

[0104] Petroleum hydrocarbon degradation rate (%) Example 6 65.4 Example 7 70.2 Example 8 75.6 Example 9 84 Example 10 80.5

[0105] From the comparison of Examples 6 to 8, it can be seen that for oil-contaminated soil with an oil content greater than 10%, under the action of the self-heating soil petroleum hydrocarbon degradation treatment agent in this embodiment, the optimal dosage of petroleum hydrocarbon degrading bacteria is 3% of the mass of the petroleum hydrocarbon contaminated soil.

[0106] The self-heating soil petroleum hydrocarbon degradation treatment agent proposed by the present invention is prepared by mixing denitrifying bacteria, microbial agents, microbial degradation nutrient solution, sodium nitrate, ammonium chloride, and expanded vermiculite. The preparation method is simple, the raw materials are easily available, and the cost is controllable. Denitrifying bacteria slowly decompose sodium nitrate into sodium nitrite to provide a reactant for the subsequent heat-generating reaction, which triggers the subsequent slow reaction of sodium nitrite and ammonium chloride. The microbial fermentation reaction provides heat for the chemical reaction, and the heat generated by the chemical reaction provides heat for the petroleum hydrocarbon degradation process. The expanded vermiculite can store this heat for 7-9 days. The self-heating soil petroleum hydrocarbon degradation treatment agent solves the problems of violent and uncontrollable reactions of conventional exothermic initiators, and the low temperature during the implementation of microbial technology for on-site treatment of oily sludge, which causes the microorganisms to be unable to function, and ensures the promotion and application of microbial treatment of oil-contaminated soil technology.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A self-heating soil petroleum hydrocarbon degradation treatment agent, characterized in that: Including denitrifying bacteria, microbial agents, microbial degradation nutrient solution, nitrate, ammonium salt and expanded vermiculite; The dosage of the denitrifying bacteria is 1%-3% of the mass of the petroleum hydrocarbon-contaminated soil; The microbial agent is a petroleum hydrocarbon degrading bacterium, and the dosage is 1%-3% of the mass of the petroleum hydrocarbon contaminated soil; The mass ratio of sodium nitrate to denitrifying bacteria is 0.5-0.7:1; The mass ratio of ammonium chloride to sodium nitrate is 1-1.5:1; The dosage of the expanded vermiculite is 2%-3% of the mass of the petroleum hydrocarbon contaminated soil.

2. The self-heating soil petroleum hydrocarbon degradation treatment agent according to claim 1, characterized in that: The main strain of denitrifying bacteria is Pseudomonas alcaligenes.

3. The self-heating soil petroleum hydrocarbon degradation treatment agent according to claim 1, characterized in that: The main strains of the petroleum hydrocarbon degrading bacteria are Bacillus pumilus, Pseudomonas monteri or Acinetobacter luffii.

4. The self-heating soil petroleum hydrocarbon degradation treatment agent according to claim 1, characterized in that: The dosage of the microbial degradation nutrient solution is 1% of the mass of the petroleum hydrocarbon-contaminated soil.

5. The self-heating soil petroleum hydrocarbon degradation treatment agent according to claim 1, characterized in that: The nitrate is sodium nitrate; the ammonium salt is ammonium chloride.

6. The self-heating soil petroleum hydrocarbon degradation treatment agent according to claim 1, characterized in that: Denitrifying bacteria come from the soil and are obtained through purification and expansion.

7. The self-heating soil petroleum hydrocarbon degradation treatment agent according to claim 1, characterized in that: The denitrifying bacteria are solid brown powder, and the microbial agent is a solid agent.

8. The method for using the self-heating soil petroleum hydrocarbon degradation agent according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) mixing oil-contaminated soil, denitrifying bacteria, microbial agents, sodium nitrate, ammonium chloride and expanded vermiculite, and composting after being fully mixed by an on-site mixer; (2) Mix the microbial degradation nutrient solution with water and dilute it, then spray it onto the pile to provide nutrients for the microbial agents and denitrifying bacteria in the pile, and cover the surface with a plastic film to keep the pile moist; (3) Depending on the oil content, after 3-7 days of composting, denitrifying bacteria convert sodium nitrate into sodium nitrite, and the sodium nitrite reacts with ammonium chloride to generate heat. The heat is kept for 7-9 days to obtain the treated oil-contaminated soil.

9. The method of use according to claim 8, characterized in that: In step (1), the optimal stacking height is 70 cm.

10. The method of use according to claim 8, characterized in that: In step (2), the microbial degradation nutrient solution and water are mixed in a ratio of 1:5.