Petroleum hydrocarbon pollution remediation method based on soil microorganisms

Abstract

The invention provides a petroleum hydrocarbon pollution remediation method based on soil microorganisms, and provides an innovative solution aiming at the problems of high cost, high energy consumption and secondary pollution of an existing remediation technology. The method comprises the following steps: firstly, carrying out sampling analysis and pretreatment on polluted soil, screening out a microbial strain capable of efficiently degrading petroleum hydrocarbon, and fixing the microbial strain on a biochar carrier to form an immobilized microbial composite material; then, the material is added into the contaminated soil, and tolerant plants are planted to construct a combined remediation system. Meanwhile, nutrient substances such as nitrogen and phosphorus and a surfactant are added, so that the bioavailability and the microbial degradation efficiency of the petroleum hydrocarbon are improved. In the repairing process, the petroleum hydrocarbon content and the microbial activity are monitored regularly, and the repairing scheme is dynamically adjusted. According to the method, the biochar is prepared from agricultural waste, the cost is reduced, efficient and environment-friendly remediation is achieved by combining the synergistic effect of microorganisms and plants, and the method has remarkable economic and environmental benefits and is suitable for treatment of soil polluted by various petroleum hydrocarbons.

Description

Technical Field

[0001] The invention provides a petroleum hydrocarbon pollution remediation method, belongs to the technical field of soil remediation, and particularly relates to a petroleum hydrocarbon pollution remediation method based on soil microorganisms. Background Art

[0002] Soil remediation technology refers to a series of technical measures to treat and restore polluted or degraded soil through physical, chemical or biological means to improve soil quality, reduce pollutant concentrations, and restore soil ecological functions. Its main functions include removing or reducing pollutants in the soil, such as heavy metals, organic pollutants and petroleum hydrocarbons, reducing their harm to the ecological environment and human health; restoring soil fertility and biological activity, promoting the reconstruction of soil ecosystems, and improving the sustainable use of soil; at the same time, by repairing contaminated soil, it can also reduce the waste of land resources, ensure the stability of agricultural production and ecosystems, and provide important support for environmental protection and sustainable development.

[0003] Existing soil remediation technologies mainly include physical remediation, chemical remediation and biological remediation. Physical remediation, such as soil replacement, electric remediation and thermal desorption, has high remediation efficiency, but has problems such as high cost, high energy consumption and possible damage to soil structure. For example, thermal desorption requires a lot of energy, and electric remediation may have a certain impact on the soil ecological environment. Chemical remediation includes chemical oxidation, chemical reduction and chemical leaching. Although the remediation speed is fast, the operation is complicated and may cause secondary pollution, causing damage to the soil structure and ecological environment. Summary of the invention

[0004] In order to make up for the deficiencies of the prior art, the embodiments of the present application provide a method for remediating petroleum hydrocarbon pollution based on soil microorganisms, thereby solving the problems of high cost, high energy consumption and possible secondary pollution in the prior art remediation technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for remediating petroleum hydrocarbon pollution based on soil microorganisms, comprising the following steps:

[0006] A. Pretreatment of contaminated soil: Sampling and analysis of soil contaminated by petroleum hydrocarbons to determine the type and concentration of petroleum hydrocarbons, and preliminary treatment of the soil, such as removing large impurities and adjusting soil moisture.

[0007] B. Screening of efficient degradation strains: Microbial strains with efficient degradation capabilities for petroleum hydrocarbons are screened out from contaminated soil, including but not limited to Pseudomonas, Bacillus and Nocardia.

[0008] C. Preparation of biochar carrier: Biochar is prepared by pyrolysis technology using agricultural waste. Biochar has a porous structure and can adsorb and fix microorganisms.

[0009] D. Preparation of immobilized microorganisms: The selected efficient degradation strains are inoculated onto biochar, and the microorganisms are immobilized by adsorption and embedding to form an immobilized microbial biochar composite material.

[0010] E. Construction of remediation system: Add immobilized microbial biochar composites to contaminated soil, and plant plants suitable for the local environment to construct a microbial-plant combined remediation system.

[0011] F. Addition of nutrients and surfactants: Add appropriate amounts of nutrients such as nitrogen and phosphorus, as well as surfactants to the soil to improve the bioavailability of petroleum hydrocarbons and the degradation capacity of microorganisms.

[0012] G. Regular monitoring and adjustment: During the remediation process, regularly monitor the content of petroleum hydrocarbons and the activity of microorganisms in the soil, and adjust the remediation plan based on the monitoring results, such as adjusting the amount of nutrients and surfactants added.

[0013] Preferably: the step of screening the efficient degradation strain in step B comprises:

[0014] Collect contaminated soil samples and conduct enrichment culture;

[0015] Through separation and purification technology, microbial strains with the ability to degrade petroleum hydrocarbons are screened out;

[0016] Molecular biology techniques were used to identify the strains.

[0017] Preferably: the preparation step of the biochar carrier in step C comprises:

[0018] Drying and crushing agricultural waste;

[0019] Pyrolysis is performed at a temperature of 300-700°C to prepare biochar;

[0020] Biochar is activated to increase its specific surface area and pore structure.

[0021] Preferably: the preparation steps of the immobilized microorganisms in step D include:

[0022] The screened efficient degradation strains were inoculated onto biochar to immobilize the microorganisms by adsorption and embedding;

[0023] Cultivate under suitable temperature and humidity conditions to improve the immobilization effect and activity of microorganisms.

[0024] Preferably: the selection of plants in step E includes but is not limited to:

[0025] Plants that tolerate petroleum hydrocarbon pollution, such as ryegrass and alfalfa;

[0026] Plant root exudates can promote microbial growth and petroleum hydrocarbon degradation.

[0027] Preferably, the addition of nutrients in step 6 includes:

[0028] Nitrogen source: The amount of nitrogen source added accounts for 30%-50% of the total nutrient addition, among which urea and ammonium nitrate are added after being mixed in a mass ratio of 1:1.

[0029] Phosphorus source: The amount of phosphorus source added accounts for 20%-40% of the total nutrient addition, among which potassium dihydrogen phosphate and superphosphate are mixed in a mass ratio of 1:1 and then added.

[0030] Other trace elements: The amount of other trace elements added accounts for 1%-5% of the total nutrient addition, among which iron, manganese and zinc are added at the ratio of 5-10 mg, 2-5 mg and 1-3 mg per kilogram of soil respectively.

[0031] The addition of the surfactant includes:

[0032] Sucrose esters: Adjusted according to the concentration and type of petroleum hydrocarbons in the soil.

[0033] Tween series surfactants: adjusted according to the concentration and type of petroleum hydrocarbons in the soil.

[0034] Preferably, the regular monitoring and adjustment step in step G includes:

[0035] Regularly monitor the content of petroleum hydrocarbons in the soil, using analytical methods such as gas chromatography-mass spectrometry;

[0036] Regularly monitor the activity of microorganisms using techniques such as fluorescent quantitative PCR;

[0037] Adjust the amount of nutrients and surfactants added according to the monitoring results to ensure the repair effect.

[0038] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0039] In order to make up for the deficiencies of the prior art, the embodiments of the present application provide a method for remediating petroleum hydrocarbon pollution based on soil microorganisms, which solves the problems of high cost, high energy consumption and possible secondary pollution in the existing remediation technology. The method realizes the effective remediation of petroleum hydrocarbon contaminated soil through the steps of pretreatment of contaminated soil, screening of efficient degradation strains, preparation of biochar carriers, preparation of immobilized microorganisms, construction of remediation system, addition of nutrients and surfactants, and regular monitoring and adjustment. Specifically, biochar prepared from agricultural waste is used as a carrier to immobilize efficient degradation strains, which not only reduces costs but also improves the degradation ability and stability of microorganisms. At the same time, by adding appropriate amounts of nutrients and surfactants, the bioavailability of petroleum hydrocarbons and the degradation efficiency of microorganisms are further improved. In addition, the constructed microorganism-plant joint remediation system gives full play to the synergistic effect of microorganisms and plants, effectively reduces the remediation cost and energy consumption, and avoids the generation of secondary pollution.

[0040] Other advantages, objectives and features of the present invention will be set forth in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a flow chart of a method for remediating petroleum hydrocarbon pollution based on soil microorganisms;

[0042] Figure 2 A detailed description of the key steps of a method for remediating petroleum hydrocarbon pollution based on soil microorganisms of the present invention;

[0043] Figure 3 This is a diagram showing the composition of additives in a method for remediating petroleum hydrocarbon pollution based on soil microorganisms according to the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that the terms “vertical”, “horizontal”, “up”, “down”, “left”, “right” and similar expressions used in this document are only for illustrative purposes and do not represent the only implementation method.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the term "and / or" used herein includes any and all combinations of one or more related listed items.

[0047] like Figure 1 The present invention relates to a method for remediating petroleum hydrocarbon pollution based on soil microorganisms, comprising the following steps:

[0048] 1. Pretreatment of contaminated soil: Sampling and analysis of soil contaminated by petroleum hydrocarbons to determine the type and concentration of petroleum hydrocarbons, and preliminary treatment of the soil, such as removing large impurities and adjusting soil moisture.

[0049] 2. Screening of efficient degradation strains: Screen out microbial strains with efficient degradation capabilities for petroleum hydrocarbons from contaminated soil, including but not limited to Pseudomonas, Bacillus and Nocardia.

[0050] 3. Preparation of biochar carrier: Biochar is prepared by pyrolysis technology using agricultural waste. Biochar has a porous structure and can adsorb and fix microorganisms.

[0051] 4. Preparation of immobilized microorganisms: The selected efficient degradation strains are inoculated onto biochar, and the microorganisms are immobilized by adsorption and embedding to form an immobilized microbial biochar composite material.

[0052] 5. Construction of remediation system: Add immobilized microbial biochar composites to contaminated soil, and plant plants suitable for the local environment to construct a microbial-plant combined remediation system.

[0053] 6. Addition of nutrients and surfactants: Add appropriate amounts of nutrients such as nitrogen and phosphorus, as well as surfactants to the soil to improve the bioavailability of petroleum hydrocarbons and the degradation capacity of microorganisms.

[0054] 7. Regular monitoring and adjustment: During the remediation process, regularly monitor the content of petroleum hydrocarbons and the activity of microorganisms in the soil, and adjust the remediation plan based on the monitoring results, such as adjusting the amount of nutrients and surfactants added.

[0055] In this embodiment, agricultural waste is innovatively used to prepare biochar as a carrier of microorganisms, which not only realizes the resource utilization of waste and reduces the cost of repair, but also improves the adsorption and fixation effect of microorganisms through the porous structure of biochar, and enhances the stability and degradation ability of microorganisms in soil. At the same time, by screening microbial strains with efficient degradation ability of petroleum hydrocarbons and immobilizing them on biochar, an immobilized microorganism-biochar composite material is formed, which further improves the degradation efficiency and stability of microorganisms. In addition, the constructed microorganism-plant joint repair system gives full play to the synergistic effect of microorganisms and plants. Plant root secretions can promote the growth of microorganisms and the degradation of petroleum hydrocarbons. At the same time, the root system of plants can also increase the air permeability and permeability of the soil, which is conducive to the activity of microorganisms and the degradation of petroleum hydrocarbons. In the repair process, by adding appropriate amounts of nutrients such as nitrogen and phosphorus and surfactants, the bioavailability of petroleum hydrocarbons and the degradation ability of microorganisms are further improved, and the repair process is accelerated. Regular monitoring and adjustment of the repair plan ensures the stability and reliability of the repair effect, and timely adjusts the amount of nutrients and surfactants added according to the monitoring results, optimizes the repair plan, and improves the repair efficiency. In summary, the present invention effectively solves the problems of high cost, high energy consumption and possible secondary pollution in existing remediation technologies through a series of innovative technical means and implementation points, and provides a new efficient, environmentally friendly and economical method for the remediation of petroleum hydrocarbon contaminated soil.

[0056] like Figure 2 As shown, the key steps of the present invention are described in detail

[0057] 1. Screening of efficient degradation strains:

[0058] Collect contaminated soil samples for enrichment culture.

[0059] Microbial strains with the ability to degrade petroleum hydrocarbons are screened out through separation and purification technology.

[0060] Molecular biology techniques were used to identify the strains.

[0061] 2. Preparation of biochar carrier:

[0062] Dry and crush agricultural waste.

[0063] The biochar is prepared by pyrolysis at a temperature of 300-700°C.

[0064] Biochar is activated to increase its specific surface area and pore structure.

[0065] 3. Preparation of immobilized microorganisms:

[0066] The screened efficient degradation strains were inoculated onto biochar, and the microorganisms were immobilized by adsorption and embedding.

[0067] Cultivate under suitable temperature and humidity conditions to improve the immobilization effect and activity of microorganisms.

[0068] 4. Plant selection:

[0069] Choose plants that are tolerant to petroleum hydrocarbon pollution, such as ryegrass, alfalfa, etc.

[0070] Select plants whose root exudates promote microbial growth and petroleum hydrocarbon degradation.

[0071] In this embodiment, an efficient microorganism-plant joint repair system is constructed through key steps such as the screening of efficient degradation strains, the preparation of biochar carriers, the preparation of immobilized microorganisms, and the selection of plants. First, by collecting contaminated soil samples and enriching and culturing them, separation and purification technology and molecular biology techniques are used to screen and identify microbial strains with efficient degradation capabilities for petroleum hydrocarbons, laying the foundation for subsequent repair work. Secondly, biochar is prepared from agricultural waste, and biochar with a porous structure is prepared by drying, crushing, pyrolysis and activation treatment, which provides a good carrier for the adsorption and fixation of microorganisms. Then, the screened efficient degradation strains are inoculated on biochar, the microorganisms are immobilized by adsorption and embedding, and cultured under suitable conditions, which improves the immobilization effect and activity of the microorganisms. Finally, plants that tolerate petroleum hydrocarbon pollution and whose root secretions can promote microbial growth and petroleum hydrocarbon degradation, such as ryegrass, alfalfa, etc., are selected to construct a microorganism-plant joint repair system, giving full play to the synergistic effect of microorganisms and plants, improving the bioavailability of petroleum hydrocarbons and the degradation ability of microorganisms, and effectively solving the problems of high cost, high energy consumption and possible secondary pollution in existing repair technologies.

[0072] like Figure 3 As shown, the composition of the additive of the present invention

[0073] 1. Addition of nutrients:

[0074] Nitrogen source: The amount of nitrogen source added accounts for 30%-50% of the total nutrient addition, among which urea and ammonium nitrate are added after being mixed in a mass ratio of 1:1.

[0075] Phosphorus source: The amount of phosphorus source added accounts for 20%-40% of the total nutrient addition, among which potassium dihydrogen phosphate and superphosphate are mixed in a mass ratio of 1:1 and then added.

[0076] Other trace elements: The amount of other trace elements added accounts for 1%-5% of the total nutrient addition, among which iron, manganese and zinc are added at the ratio of 5-10 mg, 2-5 mg and 1-3 mg per kilogram of soil respectively.

[0077] 2. Addition of surfactant:

[0078] Sucrose esters: Adjusted according to the concentration and type of petroleum hydrocarbons in the soil.

[0079] Tween series surfactants: adjusted according to the concentration and type of petroleum hydrocarbons in the soil.

[0080] 3. Regular monitoring and adjustment:

[0081] The content of petroleum hydrocarbons in the soil is monitored regularly, using analytical methods such as gas chromatography-mass spectrometry.

[0082] Monitor the activity of microorganisms regularly using techniques such as fluorescent quantitative PCR.

[0083] Adjust the amount of nutrients and surfactants added according to the monitoring results to ensure the repair effect.

[0084] In this embodiment, the repair effect is further optimized by accurately proportioning and scientifically adjusting the addition of nutrients and surfactants. This proportion ensures the nutritional balance required by microorganisms in the process of degrading petroleum hydrocarbons, and improves the activity and degradation efficiency of microorganisms. The addition of surfactants is flexibly adjusted according to the concentration and type of petroleum hydrocarbons in the soil. The use of sucrose esters and Tween series surfactants effectively improves the bioavailability of petroleum hydrocarbons and promotes the degradation of petroleum hydrocarbons by microorganisms. In addition, regular monitoring and adjustment steps are performed, and the content of petroleum hydrocarbons in the soil is monitored by using advanced analytical methods such as gas chromatography-mass spectrometry, and the activity of microorganisms is monitored by technologies such as fluorescent quantitative PCR. The addition of nutrients and surfactants is adjusted in time according to the monitoring results, ensuring the dynamic optimization of the repair process and the stability of the repair effect, thereby effectively solving the problems of high cost, high energy consumption and possible secondary pollution in existing repair technologies, and providing a new method of efficient, environmentally friendly and economical repair of petroleum hydrocarbon-contaminated soil.

[0085] When in use, firstly, the soil contaminated by petroleum hydrocarbons is sampled and analyzed to determine the type and concentration of petroleum hydrocarbons, and the soil is pretreated, such as removing large impurities and adjusting soil moisture; then, microbial strains with high efficiency in degrading petroleum hydrocarbons are screened out from the contaminated soil, including but not limited to Pseudomonas, Bacillus and Nocardia, and the types of strains are identified by molecular biology techniques; then, biochar is prepared by pyrolysis technology using agricultural waste, and the screened high-efficiency degradation strains are inoculated onto the biochar, and the microorganisms are immobilized by adsorption and embedding to form an immobilized microorganism-biochar composite material; then, the immobilized microorganism-biochar composite material is added to the contaminated soil, and plants suitable for the local environment are planted to construct a microorganism-plant joint remediation system; appropriate amounts of nutrients such as nitrogen and phosphorus and surfactants are added to the soil to improve the bioavailability of petroleum hydrocarbons and the degradation ability of microorganisms; finally, the content of petroleum hydrocarbons in the soil and the activity of microorganisms are regularly monitored during the remediation process, and the remediation plan is adjusted according to the monitoring results, such as adjusting the amount of nutrients and surfactants added to ensure the remediation effect.

[0086] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for remediating petroleum hydrocarbon pollution based on soil microorganisms, characterized in that: The following steps are involved: A. Pretreatment of contaminated soil: Sampling and analysis of soil contaminated by petroleum hydrocarbons to determine the type and concentration of petroleum hydrocarbons, and preliminary treatment of the soil, such as removing large impurities and adjusting soil moisture. B. Screening of efficient degradation strains: Microbial strains with efficient degradation capabilities for petroleum hydrocarbons are screened out from contaminated soil, including but not limited to Pseudomonas, Bacillus and Nocardia. C. Preparation of biochar carrier: Biochar is prepared by pyrolysis technology using agricultural waste. Biochar has a porous structure and can adsorb and fix microorganisms. D. Preparation of immobilized microorganisms: The selected efficient degradation strains are inoculated onto biochar, and the microorganisms are immobilized by adsorption and embedding to form an immobilized microbial biochar composite material. E. Construction of remediation system: Add immobilized microbial biochar composites to contaminated soil, and plant plants suitable for the local environment to construct a microbial-plant combined remediation system. F. Addition of nutrients and surfactants: Add appropriate amounts of nutrients such as nitrogen and phosphorus, as well as surfactants to the soil to improve the bioavailability of petroleum hydrocarbons and the degradation capacity of microorganisms. G. Regular monitoring and adjustment: During the remediation process, regularly monitor the content of petroleum hydrocarbons and the activity of microorganisms in the soil, and adjust the remediation plan based on the monitoring results, such as adjusting the amount of nutrients and surfactants added.

2. The method for remediating petroleum hydrocarbon pollution based on soil microorganisms according to claim 1, characterized in that: The screening step of the efficient degradation strain in step B comprises: 1) Collect contaminated soil samples and conduct enrichment culture; 2) Screening out microbial strains that have the ability to degrade petroleum hydrocarbons through separation and purification technology; 3) Use molecular biology techniques to identify the strain type.

3. The method for remediating petroleum hydrocarbon pollution based on soil microorganisms according to claim 1, characterized in that: The preparation steps of the biochar carrier in step C include: 1) Drying and crushing agricultural waste; 2) Pyrolysis at a temperature of 300-700°C to prepare biochar; 3) Activate the biochar to increase its specific surface area and pore structure.

4. The method for remediating petroleum hydrocarbon pollution based on soil microorganisms according to claim 1, characterized in that: The preparation steps of the immobilized microorganisms in step D include: 1) The selected efficient degradation strains were inoculated onto biochar and immobilized by adsorption and embedding. thing; 2) Cultivate under suitable temperature and humidity conditions to improve the immobilization effect and activity of microorganisms.

5. The method for remediating petroleum hydrocarbon pollution based on soil microorganisms according to claim 1, characterized in that: The selection of plants in step E includes but is not limited to: Plants that tolerate petroleum hydrocarbon pollution, such as ryegrass and alfalfa; Plant root exudates can promote microbial growth and petroleum hydrocarbon degradation.

6. The method for remediating petroleum hydrocarbon pollution based on soil microorganisms according to claim 1, characterized in that: The addition of nutrients in step 6 includes: Nitrogen source: The amount of nitrogen source added accounts for 30%-50% of the total nutrient addition, among which urea and ammonium nitrate are added after being mixed in a mass ratio of 1:

1. Phosphorus source: The amount of phosphorus source added accounts for 20%-40% of the total nutrient addition, among which potassium dihydrogen phosphate and superphosphate are mixed in a mass ratio of 1:1 and then added. Other trace elements: The amount of other trace elements added accounts for 1%-5% of the total nutrient addition, among which iron, manganese and zinc are added at the ratio of 5-10 mg, 2-5 mg and 1-3 mg per kilogram of soil respectively. The addition of the surfactant includes: Sucrose esters: Adjusted according to the concentration and type of petroleum hydrocarbons in the soil. Tween series surfactants: adjusted according to the concentration and type of petroleum hydrocarbons in the soil.

7. The method for remediating petroleum hydrocarbon pollution based on soil microorganisms according to claim 1, characterized in that: The regular monitoring and adjustment steps in step G include: 1) Regularly monitor the content of petroleum hydrocarbons in the soil using analytical methods such as gas chromatography-mass spectrometry; 2) Regularly monitor the activity of microorganisms using techniques such as fluorescent quantitative PCR; 3) Adjust the amount of nutrients and surfactants added according to the monitoring results to ensure the repair effect.

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