Bioremediation agent, preparation method and application thereof, and remediation method of petroleum-contaminated soil

Abstract

The invention provides a bioremediation agent, a preparation method and application thereof and a remediation method of petroleum-contaminated soil, and the preparation method of the bioremediation agent of the petroleum-contaminated soil comprises the following steps: S1, cutting a fresh plant Fritillaria pallidiflora stem into sections, adding water, and carrying out anaerobic fermentation for 2-3 days; and S2, adding an arthrobacter strain with the inoculation amount of 1wt%-2wt% and the preservation number of CGMCC No.6581, and performing fermentation at the temperature of 25-35 DEG C for 7-10 days to prepare fimbristylis pseudogriseolus fermentation liquid, namely the bioremediation agent. According to the method, a fresh plant, namely, the fimbristylis pseudogriseolata, is used, the fermentation liquor of the fimbristylis pseudogriseolata and the plant are used as the repairing agent to degrade petroleum hydrocarbon in the polluted soil, the whole processing technology of the biological repairing agent is simple, the repairing process is convenient to operate, and the manual operation process is reduced. And meanwhile, the adopted fresh plant, namely, the fimbristylis bambusae, can be obtained everywhere, the manufacturing cost is low, various exogenous microorganisms are not introduced, and the safety of soil biological populations in the whole remediation process is not affected.

Description

Technical Field

[0001] The invention belongs to the technical field of soil remediation, and specifically relates to a bioremediation agent and a preparation method and application thereof, and a method for remediating petroleum-contaminated soil. Background Art

[0002] There are two types of bioremediation technologies for oil-contaminated soil: microbial remediation technology and phytoremediation technology. Phytoremediation technology mainly uses the absorption and transformation capabilities of plants to degrade pollutants. Although it has the advantages of low cost, simple operation and high efficiency, due to its limited remediation capacity and the need to degrade, remove, transform, assimilate and metabolize harmful pollutants in the environment with the assistance of other microorganisms, single phytoremediation technology is relatively rarely used, and the effect cannot meet the needs of oil pollution remediation. Bioremediation technology refers to biological measures that use microorganisms to absorb, transform, remove or degrade soil oil pollutants to achieve soil purification. This technology has the advantages of low cost, can remove oil pollutants from the soil, has little impact on the surrounding environment, does not cause secondary pollution, and is simple to operate. It is a widely used economic, green, clean and most promising remediation technology. However, traditional microbial remediation or phytoremediation methods are not effective for remediating oil-contaminated soil with an oil content of more than 10%, and the remediation cycle is very long.

[0003] For example, a Chinese patent document with the publication number CN106190925A and the publication date December 7, 2016, discloses a microbial remediation agent for petroleum-contaminated soil, which relates to a soil microbial remediation agent, which is composed of bacterial agents, fungal agents, and carriers. The production process is as follows: the carrier is put into a grinder for crushing, mixed with water at a volume ratio of 1:4 to obtain a coating emulsion, solid bacterial agents and fungal agents are added to a granulator at a weight ratio of 1:2 for granulation, and the coating emulsion is liquefied and sprayed on the surface of the core to obtain the microbial remediation agent. The microbial remediation agent for petroleum-contaminated soil in the document has a high remediation effect. The coating material of the outer layer of the remediation agent can provide growth nutrients for bacteria and fungi while degrading. Under a degradation time of 35 days, the degradation rate can reach 92.83%. However, the microbial remediation agent for petroleum-contaminated soil provided in this document requires a lot of materials, a complex production process, and a relatively high cost. Its effect on moderately petroleum-contaminated soil with an oil content of about 10% has not yet been evaluated. At the same time, the introduction of foreign bacteria may lead to microbial invasion and affect biosafety. Summary of the invention

[0004] In view of the problems that the production materials of petroleum-contaminated soil remediation agents are many, the production process is complex, the cost is high, and the soil microbial safety may be caused, the first purpose of the present invention is to propose a preparation method of a bioremediation agent; the second purpose is to provide a bioremediation agent for petroleum-contaminated soil; the third purpose is to provide an application of a bioremediation agent; and the fourth purpose is to provide a method for remediating petroleum-contaminated soil. The bioremediation agent of the present invention has relatively simple production ingredients, simple processing technology, does not introduce exogenous microorganisms, does not affect the safety of soil biological populations too much, and can enhance the organic matter content of poor soil at the same time; the petroleum-contaminated soil remediation process is convenient for daily maintenance and requires less manual operation.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A method for preparing a bioremediation agent for petroleum-contaminated soil comprises the following steps: S1, cutting fresh stalks of Pseudo-reed Imperata cylindrica into segments, then adding water and performing anaerobically fermentation for 2 to 3 days; S2, inoculating the Arthrobacter strain with a preservation number of CGMCC No.6581 into the fermentation product of step S1 at an inoculation amount of 1% to 2% by weight, and fermenting at a temperature of 25 to 35° C. for 7 to 10 days to prepare a fermentation liquid of Pseudo-reed caltrops, that is, a bioremediation agent.

[0006] As a further preferred embodiment, the weight percentage of the artificial reed whisk straw and water is (1-1.5):0.5.

[0007] Preferably, the anaerobic fermentation temperature is 25-35°C.

[0008] In a specific embodiment of the present invention, the cutting process is to cut the fresh plant Imperata cylindrica stems into small segments with a length of 10 to 20 mm.

[0009] A bioremediation agent for repairing petroleum-contaminated soil prepared according to the preparation method.

[0010] Application of a petroleum-contaminated soil bioremediation agent in remediating petroleum-contaminated soil.

[0011] A method for repairing petroleum contaminated soil comprises the following steps: applying a petroleum contaminated soil bioremediation agent to petroleum contaminated soil having an oil content greater than or equal to 10wt% for repair; the petroleum contaminated soil bioremediation agent is a bioremediation agent prepared by the above preparation method.

[0012] As a further preferred embodiment, the above-mentioned method for remediating petroleum-contaminated soil specifically includes the following steps: crushing the petroleum-contaminated soil, piling it into a pile with a thickness of 30 to 50 cm and placing it in a biological prefabricated bed; adding a bioremediation agent at a weight percentage of 1 to 5% and stirring it evenly, piling it in the biological prefabricated bed at a temperature of 20 to 35°C for 5 to 7 days, and scattering false reed whisk thatch seeds on the surface of the piled petroleum-contaminated soil. After 50 to 70 days, the oil content in the soil is detected. After the treatment is completed, the grown false reed whisk thatch and grass roots are collected, and finally the crude oil content in the soil is detected to complete the overall remediation process.

[0013] In a specific embodiment of the present invention, the oil content in the petroleum-contaminated soil is 10-20%.

[0014] Preferably, the sowing amount of the false reed whisk thatch seeds is 20 to 30 g per square meter.

[0015] The present invention has the following beneficial effects: The present invention uses fresh plants of Pseudo-reed whisk grass, and utilizes its fermentation liquid and the plant itself as a repair agent to degrade petroleum hydrocarbons in contaminated soil. The overall processing technology of the bioremediation agent is relatively simple, the repair process is convenient to operate, and the manual operation process is reduced. At the same time, the fresh plants of Pseudo-reed whisk grass used are available everywhere, the overall production cost is low, and a variety of exogenous microorganisms are not introduced, and the safety of soil biological populations is not affected during the overall repair process. In addition, the Pseudo-reed whisk grass that dies in autumn and winter can also provide certain organic nutrients for the soil and enhance the fertility of poor soil. Finally, for moderately petroleum-contaminated soil with an oil content of 10% to 20%, the degradation rate of petroleum hydrocarbons reaches more than 88.7% after 40 to 60 days of repair using this bioremediation agent. DETAILED DESCRIPTION

[0016] The content of the present invention can be further understood by combining the following detailed description of the preferred implementation method of the present invention and the embodiments included. Unless otherwise stated, all technical and scientific terms used in this article have the same meaning as those of ordinary skill in the art to which the present invention belongs. If the definition of a specific term disclosed in the prior art is inconsistent with any definition provided in the present invention, the definition of the term provided in the present invention shall prevail.

[0017] In view of the problems that the production materials of petroleum-contaminated soil remediation agents are large, the production process is complex, the cost is high, and soil microbial safety may be caused, and the traditional microbial method or plant method has poor remediation effect on petroleum-contaminated soil with an oil content of more than 10%, and the remediation cycle is very long, in a typical embodiment of the present application, a method for preparing a bioremediation agent for petroleum-contaminated soil is provided, comprising the following steps: S1, cutting fresh stalks of Pseudo-reed Imperata cylindrica into segments, then adding water and performing anaerobically fermentation for 2 to 3 days; S2, inoculating the Arthrobacter strain with a preservation number of CGMCC No.6581 into the fermentation product of step S1 at an inoculation amount of 1% to 2% by weight, and fermenting at a temperature of 25 to 35° C. for 7 to 10 days to prepare a fermentation liquid of Pseudo-reed caltrops, that is, a bioremediation agent.

[0018] In order to further improve the efficiency of crude oil desorption from the soil surface and improve the remediation effect of contaminated soil with an oil concentration higher than 10%, in a preferred embodiment, the weight percentage of Imperata sphaerocephala stems and water is controlled to be (1-1.5):0.5. Within this range, firstly, Imperata sphaerocephala stems can be organically combined with water to achieve the best fermentation effect. Secondly, the fermentation product obtained by the accessed Bacillus strain within this ratio is optimal and has the best implementation effect.

[0019] In a preferred embodiment, the anaerobic fermentation temperature is controlled at 25-35° C. to achieve the best fermentation effect.

[0020] In a preferred embodiment, the cutting process is to cut the fresh plant Imperata cylindrica stems into small segments with a length of 10 to 20 mm.

[0021] In the second typical embodiment of the present application, a bioremediation agent for repairing petroleum contaminated soil is provided, and the bioremediation agent is prepared by the above-mentioned preparation method. The present invention uses fresh plants of Pseudo-reed whisk grass, and utilizes its fermentation liquid and the plant itself as a repair agent to degrade petroleum hydrocarbons in contaminated soil. The overall repair agent processing technology is relatively simple, and fresh plants of Pseudo-reed whisk grass are available everywhere, which effectively reduces the production cost, and the conditions of each step in the reaction are mild, high safety, no toxic and harmful substances are produced, the repair efficiency is high, and it has a high promotion value.

[0022] In a third typical embodiment of the present application, the use of the above-mentioned bioremediation agent in the restoration of petroleum-contaminated soil is provided. The overall production cost of the bioremediation agent is low, and a variety of exogenous microorganisms are not introduced, and the safety of the soil biological population is not affected during the overall restoration process.

[0023] The present application also provides a method for repairing petroleum-contaminated soil, comprising the following steps: applying a petroleum-contaminated soil bioremediation agent to petroleum-contaminated soil with an oil content greater than or equal to 10wt% for repair. The repair speed is fast, the process is simple, and the equipment requirements are low. No secondary pollutants are generated during the repair process. The method is particularly suitable for the repair of moderately (e.g., with an oil content of 10% to 20%) petroleum-contaminated soil.

[0024] In a fourth typical embodiment of the present application, a method for remediating petroleum-contaminated soil is provided, comprising the following steps: crushing the petroleum-contaminated soil, piling it into a pile with a thickness of 30 to 50 cm and placing it in a biological prefabricated bed; adding a bioremediation agent at a weight percentage of 1 to 5% and stirring it evenly, piling it in the biological prefabricated bed at a temperature of 20 to 35°C for 5 to 7 days, scattering false reed whisk thatch seeds on the surface of the piled petroleum-contaminated soil, detecting the oil content in the soil after 50 to 70 days, and after the treatment is completed, collecting the grown false reed whisk thatch and grass roots, and finally detecting the crude oil content in the soil to complete the overall remediation process.

[0025] Furthermore, the above-mentioned method for remediating petroleum-contaminated soil is applicable to the remediation of petroleum-contaminated soil with an oil content of 10wt% to 20wt%.

[0026] In order to further improve the restoration effect of contaminated soil, the preferred sowing amount of the false reed whisk thatch seeds is 20 to 30 g per square meter.

[0027] Example 1 This embodiment relates to a bioremediation agent, which is mainly composed of Pseudocalli spatholobifolia. The preparation method of the bioremediation agent comprises the following steps: S1, taking fresh plant Aglaonema scabra, cutting its stem into small segments with a length of 10 to 15 mm, adding water at a weight percentage of 1:0.5, and performing anaerobically fermentation at a temperature of 35° C. for 2 days; S2, inoculating the Arthrobacter strain with a preservation number of CGMCC No.6581 into the fermentation product of step S1 at an inoculation amount of 1wt% by weight, and fermenting at a temperature of 35°C for 7 days to prepare a fermentation liquid of Pseudocalcinia argyi, which is a bioremediation agent.

[0028] The method for repairing petroleum-contaminated soil using the bioremediation agent is as follows: moderately petroleum-contaminated soil with an oil content of 11.20% taken from Ansai area in northern Shaanxi is crushed, piled into a pile with a thickness of 30 to 35 cm and placed in a biological prefabricated bed; the bioremediation agent is added at a weight percentage of 2% and stirred evenly, and piled in the prefabricated bed at a temperature of 25°C for 5 days, and false reed whisk grass seeds are sprinkled on the surface at a sowing rate of 20g per square meter, the crude oil content in the soil is tested every 5 to 7 days, and the oil content in the soil is tested after 60 days to evaluate the repair effect. After the treatment, the crude oil content is reduced to 1.03%, and the grown false reed whisk grass and grass roots are collected to complete the overall repair process.

[0029] Example 2 This embodiment relates to a bioremediation agent for repairing petroleum-contaminated soil, and a preparation method thereof comprises the following steps: S1, taking fresh plant Aglaonema scabra, cutting its stem into small segments with a length of 10 to 20 mm, adding water in a weight percentage of 1.2:0.5, and performing anaerobically fermentation at a temperature of 30° C. for 3 days; S2, adding an Arthrobacter strain with a preservation number of CGMCC No.6581 in an inoculation amount of 2wt%, fermenting at a temperature of 25°C for 10 days to prepare a fermentation liquid of Pseudocolobus pseudoreedii.

[0030] The method for repairing petroleum-contaminated soil using the bioremediation agent is as follows: moderately petroleum-contaminated soil with an oil content of 15.13% taken from Qingyang area of ​​Gansu Province is crushed, piled into a pile with a thickness of 40 to 45 cm and placed in a biological prefabricated bed; the bioremediation agent is added at a weight percentage of 4% and stirred evenly, and piled in the prefabricated bed at a temperature of 20°C for 7 days, and false reed whisk grass seeds are sprinkled on the surface at a sowing rate of 30g per square meter. After 70 days, the oil content in the soil is tested to evaluate the repair effect. After the treatment, the crude oil content is reduced to 1.24%, and the grown false reed whisk grass and grass roots are collected to complete the overall repair process.

[0031] Example 3 This embodiment relates to a bioremediation agent for repairing petroleum-contaminated soil, comprising the following steps: S1, taking fresh plant Aglaonema scabra, cutting its stem into small segments with a length of 15 to 20 mm, adding water in a weight percentage of 1.5:0.5, and performing anaerobically fermentation at a temperature of 25° C. for 3 days; S2, adding 2% of the Arthrobacter strain with the preservation number of CGMCC No.6581, fermenting at 30°C for 9 days to prepare the Pseudo-reed caltrop fermentation liquid.

[0032] The method for repairing petroleum-contaminated soil using the bioremediation agent is as follows: crush the moderately petroleum-contaminated soil with an oil content of 18.29% in Dingbian area of ​​northern Shaanxi, pile it into a pile with a thickness of 45 to 50 cm and place it in a biological prefabricated bed; add the bioremediation agent at a weight percentage of 5% and stir it evenly, pile it in the prefabricated bed at a temperature of 30°C for 7 days, and sprinkle false reed whisk grass seeds on its surface at a sowing rate of 25g per square meter. After 68 days, the oil content in the soil is tested to evaluate the repair effect. After the treatment, the crude oil content is reduced to 2.06%, and the grown false reed whisk grass and grass roots are collected to complete the overall repair process.

[0033] The effects of using the bioremediation agents of Examples 1-3 to repair petroleum-contaminated soil are shown in Table 1 below.

[0034] Table 1 Effect of bioremediation agents on petroleum-contaminated soil As shown in Table 1, the bioremediation agent provided by the present invention is used to repair moderately petroleum-contaminated soil, and the degradation rate of petroleum hydrocarbons reaches more than 88.7% after 60-70 days of treatment.

[0035] The above description is only a preferred embodiment of the present invention, which is merely illustrative of the present invention and does not limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made by ordinary technicians in this field to the technical solution of the present invention should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A method for preparing a bioremediation agent, characterized in that: The following steps are involved: S1, cutting fresh stalks of Pseudocalli cycads into segments, then adding water and performing anaerobically fermentation for 2 to 3 days; S2, inoculating the Arthrobacter strain with a preservation number of CGMCC No.6581 into the fermentation product of step S1 at an inoculation amount of 1% to 2% by weight, and fermenting at a temperature of 25 to 35° C. for 7 to 10 days to prepare a fermentation liquid of Pseudo-reed caltrops, that is, a bioremediation agent.

2. The method for preparing the bioremediation agent according to claim 1, characterized in that: The weight percentage of the artificial reed whisk straw and water is (1-1.5):0.

5.

3. The method for preparing the bioremediation agent according to claim 1, characterized in that: The anaerobic fermentation temperature is 25-35°C.

4. The method for preparing the bioremediation agent according to claim 1, characterized in that: The cutting process is to cut the fresh plant Psoralea corylifolia stems into small segments with a length of 10 to 20 mm.

5. A bioremediation agent for repairing petroleum-contaminated soil prepared according to the preparation method according to any one of claims 1 to 4.

6. Use of the bioremediation agent prepared according to any one of claims 1 to 4 in remediating petroleum-contaminated soil.

7. A method for remediating petroleum-contaminated soil, characterized in that: The following steps are involved: The bioremediation agent for petroleum contaminated soil is applied to petroleum contaminated soil having an oil content greater than or equal to 10 wt % for remediation; the bioremediation agent for petroleum contaminated soil is the bioremediation agent prepared according to any one of claims 1 to 4.

8. The method for remediating petroleum-contaminated soil according to claim 7, characterized in that: The following steps are involved: The petroleum-contaminated soil is crushed and piled into a pile with a thickness of 30 to 50 cm and placed in a biological prefabricated bed; a bioremediation agent is added at a weight percentage of 1 to 5% and stirred evenly, and the soil is piled in the biological prefabricated bed at a temperature of 20 to 35°C for 5 to 7 days. False reed whisk grass seeds are sprinkled on the surface of the piled petroleum-contaminated soil, and the oil content in the soil is tested after 50 to 70 days. After the treatment is completed, the grown false reed whisk grass and grass roots are collected, and finally the crude oil content in the soil is tested to complete the overall repair process.

9. The method for remediating petroleum-contaminated soil according to claim 8, characterized in that: The oil content in the petroleum-contaminated soil is 10-20%.

10. The method for remediating petroleum-contaminated soil according to claim 8, characterized in that: The sowing amount of the false reed brush thatch seeds is 20 to 30 g per square meter.

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