Method for repairing petroleum-contaminated soil through combination of surfactant and biological enhancement

Abstract

The invention discloses a method for repairing petroleum-contaminated soil through combination of a surfactant and biological enhancement, and belongs to the field of petroleum-contaminated soil repairing. The method comprises the following steps: adding an alkyl glycoside surfactant into the petroleum-contaminated soil to carry out efficient surfactant leaching on the soil, and then adding sphingomonas into the soil to carry out biological enhancement remediation on the soil. By means of the remediation process, humic acid substances in the soil are remarkably increased, and by means of treatment in the process, the solubility of TPH is improved, and the accessibility of microorganisms to the TPH is enhanced; in the bioremediation stage, the efficient surfactant can serve as a stronger additional carbon source, the number and activity of microorganisms are improved, and generation of more soil enzymes is promoted, so that the whole remediation process is accelerated, and the purpose of bioremediation of petroleum hydrocarbon in soil through combination of the surfactant and the bioremediation is achieved.

Description

Technical Field

[0001] This invention belongs to the field of petroleum-contaminated soil remediation and relates to a method for remediating petroleum-contaminated soil using a combination of surfactants and bio-enhanced methods. Background Technology

[0002] Petroleum is an indispensable energy source in modern society. However, during its extraction, transportation, storage, and production, it inevitably leaks into the environment, especially into the soil. This not only severely damages the physical structure and chemical properties of the soil but also negatively impacts soil microorganisms and plant growth, and even endangers human health. Therefore, effective remediation strategies are urgently needed to restore petroleum-contaminated soil.

[0003] Currently, bioremediation technologies for petroleum-contaminated soil mainly rely on the degradation capabilities of local or exogenous microorganisms, and improve the bioavailability of pollutants by adding nutrients or biosurfactants. For example, Wang et al. isolated Pseudomonas aeruginosa DL from petroleum-contaminated sites and achieved efficient degradation of long-chain alkanes after 160 days of treatment; in addition, Wu et al. used synthetic surfactants (such as SDBS and Tween 80) to pretreat contaminated soil, which significantly improved the degradation efficiency of total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs) by subsequent microorganisms. However, the above-mentioned existing technologies still have the following unresolved defects: (1) Long remediation cycle: the current surfactant combined with petroleum-degrading bacteria still requires ≥90 days for high-concentration or aged soils, and the TPH degradation rate is often <50%, which is difficult to meet the requirements of emergency engineering repairs. (2) Secondary risks: synthetic surfactants SDBS and Tween 80 have long-lasting residues and high toxicity, which can easily inhibit native degrading bacteria and cause secondary soil pollution. (3) Blank in research on green surfactants: Although APG is degradable and non-toxic, there is still a lack of systematic data on the optimal dosage, timing and synergistic mechanism of its combined use with petroleum-degrading bacteria. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for remediating petroleum-contaminated soil by combining surfactants with bio-enhanced methods, so as to solve the problems of excessively long soil remediation time and easy soil contamination by surfactants in the existing surfactant-degrading bacteria combination.

[0005] To achieve the above objectives, the present invention employs the following technical solution: A method for remediating petroleum-contaminated soil using a surfactant-based combined bio-enhanced approach includes the following steps: S1, adding one or more alkyl glycoside surfactants to petroleum-contaminated soil to leach the soil; the alkyl glycoside surfactant is a mixed solution of alkyl glycoside and water, used to adjust the soil water-soil ratio. S2 involves adding *Sphingomonas sphingolipidae* to the soil after leaching in S1 for bio-enhanced remediation. During the bio-enhanced remediation process, the alkyl glycoside surfactant is used to provide a carbon source, which can promote the growth of *Sphingomonas sphingolipidae*, increase the number and activity of microorganisms, and promote the production of soil enzymes.

[0006] A further improvement of the present invention is that: Preferably, in S1, the alkyl glycoside is one or more of APG IC911, APG 0810, and APG 0814.

[0007] Preferably, in S1, the alkyl glycoside in the alkyl glycoside surfactant is APG IC911 and APG 0810 in a molar ratio of 6:4.

[0008] Preferably, the concentration of the alkyl glycoside surfactant in S1 is 5-20 g / L.

[0009] Preferably, in S1, the water-to-soil ratio of the soil is (4-20):1.

[0010] Preferably, in S1, the rinsing time is 1-7 hours.

[0011] Preferably, in S1, the pH value of the alkyl glycoside surfactant is 3-11.

[0012] Preferably, sodium dihydrogen phosphate and urea are also added to S2, so that the final nitrogen content in the soil is 312.7 mg / kg and the phosphorus content is 31.33 mg / kg.

[0013] Preferably, in step S1, the concentration of the alkyl glycoside surfactant solution is 15 g / L, the water-to-soil ratio is 10:1, the rinsing time is 2 hours, and the pH value is 7.

[0014] Preferably, in S2, 10 mL of Sphingomyelin-monocytozoon is added to every 100 g of soil.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for the combined remediation of petroleum-contaminated soil using surfactants and bio-enhanced methods. This method, through leaching with highly efficient surfactants, significantly increases humic acid content, improving not only the solubility of total hydrochloric acid (TPH) but also enhancing microbial accessibility to TPH. During the bioremediation phase, the highly efficient surfactants act as a stronger additional carbon source, increasing the number and activity of microorganisms and promoting the production of more soil enzymes, thereby accelerating the entire remediation process and achieving the goal of combined surfactant and bioremediation of petroleum hydrocarbons in soil. Verification showed that the TPH degradation rate was increased to >85% within 60 days, achieving rapid remediation of highly concentrated, aged contaminated soil. The use of fully biodegradable alkyl glycosides (APG) to replace synthetic surfactants eliminates secondary pollution. This invention systematically establishes the synergistic parameters between APG and indigenous highly efficient degrading bacteria, forming a green enhanced remediation process that can be engineered. The method of this invention also has the following advantages: (1) In contaminated soil with only added nutrients, the degradation rate of TPH was only 4.80% (2321.82 mg / kg). In contrast, in contaminated soil after leaching with non-efficient surfactants and after leaching with efficient surfactants, the degradation rate of TPH increased to 8.51% (4118.47 mg / kg) and 12.84% (8831.53 mg / kg), respectively. However, the biological removal of TPH did not increase significantly. In addition, the number of microorganisms was almost unchanged in contaminated soil with only added nutrients and in contaminated soil after leaching with non-efficient surfactants and after leaching with efficient surfactants, respectively. Therefore, the low number of indigenous microorganisms may be the main reason for the relatively low degradation rate.

[0016] (2) Compared with the supernatant before surfactant rinsing, rinsing with both high-efficiency and low-efficiency surfactants significantly increased the fluorescence intensity of humic acid compounds (region V). This increase not only improves the solubility of TPH but also enhances the accessibility of TPH to microorganisms. During bioremediation, the humic acid content in the high-efficiency group was much higher than that in the low-efficiency group. This significant increase in humic acid content can be attributed to the fact that more total petroleum hydrocarbons (TPH) in the high-efficiency group were decomposed into smaller organic molecules by microorganisms. These smaller organic molecules further polymerized in subsequent processes to form humic acid compounds.

[0017] (3) By comparing the changes in nutrient consumption in the high-efficiency group and the non-high-efficiency group, the microorganisms in the high-efficiency group showed higher metabolic efficiency and activity in degrading TPH. In addition, the higher hydrocarbon conversion rate and carbon-nitrogen conversion rate of the high-efficiency group indicate that the microorganisms in the high-efficiency group have higher activity and can better promote the rapid degradation of petroleum hydrocarbons.

[0018] (4) The high-efficiency group had a high number and high activity of microbial communities. In addition, the gene expression levels encoding soil enzymes (dehydrogenase and catalase) were also higher than those of the non-high-efficiency group. After adding glucose, non-high-efficiency surfactant and high-efficiency surfactant, Sphingomonas sphingolipidae were added to the soil. It was found that the number of microorganisms and the amount of TPH removed in the high-efficiency group were both very large. This was mainly because the high-efficiency surfactant, as a stronger additional carbon source, accelerated the biodegradation process through the cometabolite pathway. Attached Figure Description

[0019] Figure 1 This is a single-factor experimental method; Among them, (a) shows the effect of surfactants APG IC911, APG 0810 and APG 0814 on the removal of petroleum hydrocarbons at different surfactant concentrations (0, 1, 2, 3, 4 and 5 wt.%); (b) The figure shows the effect of surfactants APG IC911, APG 0810 and APG 0814 on the removal of petroleum hydrocarbons at different washing times (1, 3, 5 and 7 hours); (c) The figure shows the effect of surfactants APG IC911, APG 0810 and APG 0814 on the removal of petroleum hydrocarbons at different water-to-soil ratios (4:1, 6:1, 8:1, 10:1, 15:1 and 20:1); (d) The figure shows the effect of surfactants APG IC911, APG 0810 and APG 0814 on the removal of petroleum hydrocarbons at different pH values ​​(3, 5, 7, 9 and 11); Figure 2 The diagram shows the effect of removal efficiency; Among them, (a) shows the petroleum hydrocarbon removal amount and removal efficiency of APG IC911 and APG 0810 under different compounding ratios; (b) Figure shows the removal amount and efficiency of petroleum hydrocarbons by APG IC911 and APG 0814 at different compounding ratios; (c) Figure: Petroleum hydrocarbon removal amount and removal efficiency of APG 0810 and APG 0814 at different compounding ratios; Figure 3 The graph shows the effect of different surfactants on TPH removal efficiency. Among them, (a) shows the removal effect of high-efficiency surfactant on petroleum hydrocarbons in soil columns with different concentrations and rinsing times; (b) The figure shows the removal effect of non-efficient surfactants on petroleum hydrocarbons in soil columns at different concentrations and rinsing times; Figure 4 For surfactant rinsing devices; Figure 5 For comparison; Figure (a) shows a comparison of the removal of total petroleum hydrocarbons by surfactant rinsing and biodegradation between the high-efficiency group and the non-high-efficiency group. (b) The figure shows a comparison of the removal of carbon chains in the biodegradation between the high-efficiency group and the low-efficiency group; (c) The figure shows a comparison of petroleum hydrocarbon removal between the high-efficiency group and the low-efficiency group at different remediation times during biodegradation; Figure 6 It is a three-dimensional fluorescence spectrum; Figure (a) shows the three-dimensional fluorescence spectrum of the non-high efficiency group before surfactant rinsing; (b) The figure shows the three-dimensional fluorescence spectrum of the non-high efficiency group after surfactant rinsing; (c) The figure shows the three-dimensional fluorescence spectrum of the non-efficient group after bioremediation; (d) The figure shows the three-dimensional fluorescence spectrum of the high-efficiency group before surfactant rinsing; (e) The figure shows the three-dimensional fluorescence spectrum of the high-efficiency group after rinsing with surfactant; (f) The figure shows the three-dimensional fluorescence spectrum of the high-efficiency group after bioremediation; Figure 7 A graph showing the changes in process components; Figure (a) shows the changes in dissolved organic carbon (DOC) in the high-efficiency group and the low-efficiency group during bioremediation. (b) The figure shows the difference in ammonium nitrogen (NH4+) between the high-efficiency group and the low-efficiency group during bioremediation. + -N) changes; (c) The figure shows the difference in nitrate nitrogen (NO3) between the high-efficiency group and the non-high-efficiency group during bioremediation. - -N) changes; (d) The figure shows the difference in nitrite nitrogen (NO2) between the high-efficiency group and the non-high-efficiency group during bioremediation. - -N) changes; (e) The figure shows the changes in carbon / hydrogen conversion rate during bioremediation in the high-efficiency group and the low-efficiency group; (f) The figure shows the changes in carbon / nitrogen conversion rate in the high-efficiency group and the low-efficiency group during bioremediation; Figure 8 A graph showing the changes in the content of various substances; Among them, (a) is a graph showing the changes in the number of microorganisms in the high-efficiency group and the low-efficiency group during bioremediation; (b) The figure shows the change in the percentage of viable bacteria in the high-efficiency group and the low-efficiency group during bioremediation; (c) The figure shows the changes in dehydrogenase activity in the high-efficiency group and the low-efficiency group during bioremediation; (d) The figure shows the changes in catalase activity in the high-efficiency group and the low-efficiency group during bioremediation; (e) The figure shows the kinetic model of petroleum hydrocarbon degradation in the high-efficiency group and the low-efficiency group during bioremediation; (f) The figure shows a comparison of the timelines of carbon microbial degradation in the high-efficiency group and the low-efficiency group during bioremediation; Figure 9 A diagram of biological changes; Among them, (a) shows the biodegradation efficiency of petroleum hydrocarbons in soil under three treatment methods (glucose, non-efficient surfactant, and efficient surfactant); (b) The figure shows the changes in soil microbial abundance under three treatments (glucose, inefficient surfactant, and efficient surfactant); Figure 10 Graphs showing changes in total petroleum hydrocarbons and microorganisms; Figure (a) shows the removal of total petroleum hydrocarbons in soil after three treatments: no surfactant leaching, leaching with non-efficient and efficient surfactants followed by nutrient replenishment. (b) The figure shows the number of microorganisms in soil treated with non-efficient and efficient surfactants followed by nutrient replenishment. Detailed Implementation The present invention will now be described in further detail with reference to the accompanying drawings: To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0020] In this article, unless otherwise specified, the terms “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of”. For example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a”.

[0021] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0022] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0023] It should be noted in advance that the alkyl glycosides used in this application were purchased from Shanghai Fakai Chemical Co., Ltd., and are products with corresponding product numbers from their company.

[0024] This invention provides a method for remediating petroleum-contaminated soil using a combination of highly efficient surfactants and bio-enhanced methods, comprising the following steps: S1, adding one or more alkyl glycoside surfactants to petroleum-contaminated soil to leach the soil; the alkyl glycoside surfactant is a mixed solution of alkyl glycoside and water; the soil is treated to adjust the water-soil ratio; In this step, the alkyl glycoside is one of APG IC911, APG 0810, and APG 0814, and is a green functional surfactant. The alkyl glycoside surfactant is either a highly efficient surfactant composed of APG IC911 and APG 0810 in a mass ratio of 6:4, or a less efficient surfactant composed of APG 0810 and APG 0814 in a mass ratio of 6:4.

[0025] The concentration of the alkyl glycoside surfactant is 1-5 wt.%; the soil water-to-water ratio is (4-20):1; the leaching time is 1-7 h; and the pH value of the alkyl glycoside surfactant is 3-11.

[0026] It should be understood that the above water-soil ratio is the ratio of the volume of the surfactant solution to the mass of the soil.

[0027] S2 involves adding *Sphingomonas sphingolipidae* to the soil after leaching in S1 for bio-enhanced remediation. After leaching the soil column with high-efficiency and low-efficiency surfactants respectively, purified *Sphingomonas sphingolipidae* is added, thus completing the process of surfactant-based bio-enhanced remediation of petroleum-contaminated soil.

[0028] During the bioremediation phase, sodium dihydrogen phosphate (KH2PO4) and urea (CO(NH2)2) were also added, with the final concentrations being 312.7 mg / kg for nitrogen and 31.33 mg / kg for phosphorus.

[0029] In the bottle experiment, the optimal concentration was 4 wt.%, the optimal washing time was 5 hours, the optimal water-to-soil ratio was 10:1, and the optimal pH was 7. Furthermore, in the column experiment, the optimal concentration was 15 g / L, and the optimal rinsing time was 2 hours.

[0030] During the surfactant leaching stage, the high-efficiency group removed 16,562.66 mg / kg of petroleum hydrocarbons, which was 7,595.39 mg / kg more than the non-high-efficiency group. After leaching and 60 days of bioremediation, the total petroleum hydrocarbon removal rates for the high-efficiency group and the non-high-efficiency group were 85.11% and 56.29%, respectively.

[0031] In a specific example, the pH value was 8.28, the total nitrogen content was 660 mg / kg, the total phosphorus content was 640 mg / kg, the organic matter content was 51110 mg / kg, and the total petroleum hydrocarbon (TPH) concentration was 48414.97 mg / kg.

[0032] See Figure 1 To determine the above parameters, this invention discloses a process for determining a method for remediating petroleum-contaminated soil using a combination of highly efficient surfactants and bio-enhanced agents, comprising the following steps: Step 1: Among the eight alkyl glycoside surfactants, three alkyl glycoside surfactants were selected for single-factor and compound experiments based on their removal rates under the conditions of a mass ratio of 3 wt.% and a washing time of 3 hours.

[0033] Specifically, the surface activities of the eight alkyl glycosides are APG IC06, APG IC08, APG 0810, APG 0814, APG 0818, APG IC911, APG IC10 and APG 1214.

[0034] Step 2, as follows Figure 1 As shown, three surfactants were tested in single-factor and compound bottle experiments at different mass concentrations (0-5 wt.%), different washing times (0-7 hours), different water-soil ratios (4-20:1), and different pH values ​​(3-11) to determine the high-efficiency and low-efficiency surfactants.

[0035] To determine the optimal concentration of surfactant formulations, the effects of different mass concentrations (0 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, and 5 wt.%) of alkyl glycoside surfactants (APG0814, APG 0810, and APG 911) on petroleum hydrocarbon removal efficiency were investigated in a series of batch experiments. Experimental conditions were strictly controlled as follows: washing time 5 hours, water-to-soil ratio 10:1, pH 7, and room temperature. Figure 1As shown in Figure (a), the removal of petroleum hydrocarbons by the three alkyl glycoside surfactants increased with increasing surfactant concentration. When the surfactant concentration was 0 wt.%, the leaching amount of TPH was 1225.55 mg / kg for all three surfactants. With the surfactant concentration increasing to 5 wt.%, APG 0814, APG 0810, and APG 911 achieved the highest TPH removal, which were 17.75 times, 21.83 times, and 23.07 times the leaching amount when the surfactant concentration was 0, respectively, corresponding to TPH removal amounts of 21763.41 mg / kg, 26749.81 mg / kg, and 28270.39 mg / kg. When the surfactant concentrations of APG 0814, APG 0810, and APG 911 increased from 0 wt.% to 4 wt.%, the removal of petroleum hydrocarbons significantly increased. However, when the surfactant concentration exceeded 4 wt.%, the increase in removal slowed down considerably and even plateaued. There is an optimal surfactant concentration threshold; exceeding this threshold, the removal performance increases slowly or even decreases because excessive micelles may inhibit dissolution potential. Therefore, a surfactant concentration of 4 wt.% can be considered a synergistic concentration threshold and can be used as the optimal concentration for surfactant blending.

[0036] After determining the optimal surfactant concentration (4 wt.%), the effect of washing time on petroleum hydrocarbon removal was further investigated. Under conditions of 4 wt.% concentration, a water-to-soil ratio of 10:1, pH 7, and room temperature, experiments were conducted using APG 0814, APG 0810, and APG 911. Samples were taken at pre-selected time points (1, 3, 5, and 7 hours) to determine the optimal washing time for the surfactant blend. Figure 1As shown in Figure (b), the removal of petroleum hydrocarbons by the three alkyl glycoside surfactants was directly proportional to the washing time. At 1 hour, the removal amounts were 3307.55 mg / kg, 4896.56 mg / kg, and 6640.53 mg / kg, respectively. At 3 hours, the removal amounts increased by 5084.68 mg / kg, 8396.76 mg / kg, and 8204.45 mg / kg, respectively. Further at 5 hours, the removal amounts increased by 10303.72 mg / kg, 9190.08 mg / kg, and 11139.70 mg / kg, respectively. However, between 5 and 7 hours, the removal rate slowed significantly, with removal amounts increasing by only 2214.70 mg / kg, 1430.52 mg / kg, and 5103.08 mg / kg, respectively. This is because in the initial stage of treatment, the surfactant concentration was high, and its hydrophobic groups could effectively interact with the petroleum hydrocarbons, forming emulsion droplets or micelles, thereby rapidly removing the petroleum hydrocarbons. However, as time progresses, the concentration of surfactants gradually decreases, and the interaction between their hydrophobic groups and petroleum hydrocarbons weakens, resulting in a slow increase in removal efficiency. Therefore, a 5-hour rinsing time can be considered a turning point in efficiency decay and can be regarded as the optimal rinsing time for surfactant blends.

[0037] After determining the optimal surfactant concentration (4 wt.%) and optimal washing time (5 hours), the effects of different water-to-soil ratios on petroleum hydrocarbon removal efficiency were further investigated, such as... Figure 1 As shown in Figure (c), the results indicate that the removal of TPH by the three surfactants initially increased significantly and then stabilized with increasing water-to-soil ratio. Specifically, at a water-to-soil ratio of 4:1, the removal amounts of TPH by the three surfactants were 7743.66 mg / kg, 14785.81 mg / kg, and 16408.99 mg / kg, respectively. When the water-to-soil ratio increased to 10:1, the removal efficiency significantly improved, increasing by 10952.29 mg / kg, 7697.20 mg / kg, and 9575.70 mg / kg, respectively. However, when the water-to-soil ratio continued to increase to 20:1, the increase in removal efficiency slowed significantly, increasing by only 520.07 mg / kg, 1869.69 mg / kg, and 2966.96 mg / kg, respectively. These results suggest that 10:1, as an optimal water-to-soil ratio, can improve petroleum hydrocarbon removal while also saving costs.

[0038] To comprehensively optimize the formulation conditions of surfactants, the effects of different pH values ​​(3, 5, 7, 9, and 11) on the removal efficiency of petroleum hydrocarbons were investigated under optimal concentration, optimal washing time, and optimal water-to-soil ratio. Figure 1As shown in (d), the removal capacity of TPH by the three surfactants first increased and then decreased with increasing pH, exhibiting the highest removal capacity at pH 9, which were 20346.41 mg / kg, 25745.2 mg / kg, and 26672.1125 mg / kg, respectively. However, the removal efficiency decreased significantly under extreme pH conditions (3 and 11). Although the removal efficiency was highest at pH 9, pH 7 was used as the optimal operating condition considering the protection of soil properties after remediation.

[0039] APG IC911, APG 0810, and APG 0814 were combined in pairs according to the optimal mass concentration of 4 wt.%, optimal washing time of 5 hours, optimal water-to-soil ratio of 10:1, and optimal pH value of 7 in the bottle experiment. Based on the removal efficiency, a high-efficiency surfactant was obtained. The petroleum hydrocarbon removal rate of the APG IC911 combined system with APG 0810 and APG 0814 is as follows: Figure 2 As shown in the figure. Experimental results indicate that APG IC911 and APG 0810 play crucial roles in the removal of TPH. In the APG 911 and APG 0810 compound system, the TPH removal amount first increases and then decreases with the increase of the APG 911 ratio. Specifically, when the ratio of APG 911 to APG 0810 reaches 6:4, the removal efficiency of the system reaches its peak, at which point the TPH removal amount is 33069.43 mg / kg. Figure 2 As shown in Figure (a). Similarly, in the APG 911 and APG 0814 compound system, a phenomenon was observed where the TPH removal first increased and then decreased with the increase of the APG IC911 ratio. Under the condition of an APG 911 to APG 0814 ratio of 6:4, the system exhibited the highest removal efficiency, with a TPH removal of 31749.90 mg / kg. Figure 2 As shown in Figure (b). In the APG 0810 and APG 0814 compound system, the removal amount first increases and then decreases with the increase of APG 0810, and the removal amount is 26784.12 mg / kg when the ratio is 6:4 (2(c)). Based on these results, the 6:4 ratio of APG IC911 to APG 0810 is confirmed as a highly efficient surfactant, while the 6:4 ratio of APG 0810 to APG 0814 is confirmed as a less efficient surfactant.

[0040] In this process, after the surfactant solution is added to the soil for washing in the conical flask experiment, it needs to be shaken in a variable speed rotary shaker at a speed of 180 r / min and a temperature of room temperature.

[0041] Step 3, surfactant elution column experiment: The APG IC 911 and APG 0810 high-efficiency surfactants with a molar ratio of 6:4 obtained in step 2 were used in a column experiment with 50 grams of contaminated soil at room temperature. Different concentrations (0, 5, 10, 15, 20 g / L) of surfactant solutions were pumped in at a flow rate of 25 rpm using a peristaltic pump for elution. Samples were taken at pre-selected time points (0, 0.5, 1, 2, 3, and 4 hours) to evaluate the oil removal efficiency under pilot-scale conditions. See [link to relevant documentation]. Figure 3 As shown in Figures (a) and (b) in the text. From Figure 3 As shown in Figure (a), the removal of petroleum hydrocarbons by the high-efficiency surfactant is also positively correlated with concentration, reaching its maximum removal rate at 4 hours. At this point, as the concentration increases from 5 g / L to 20 g / L, the removal rate increases by 7495.27 mg / kg, 7014.49 mg / kg, and 3892.73 mg / kg, respectively. When the concentration increases from 15 g / L to 20 g / L, the TPH removal rate slows significantly; therefore, 15 g / L can be considered the optimal concentration for the high-efficiency surfactant. At 15 g / L, the removal rate of petroleum hydrocarbons by the high-efficiency surfactant shows a trend of first significantly increasing and then stabilizing with increasing rinsing time: 5425.67 mg / kg is removed within 0.5 to 1 hour; the removal rate further increases to 6426.76 mg / kg within 1 to 2 hours; and the removal rate only increases by 1161.3 mg / kg within 2 to 3 hours. Therefore, 2 hours can be considered an optimal rinsing time for the high-efficiency surfactant. It is worth noting that when the surfactant concentration is 15 g / L and the rinsing time is 2 hours, the removal capacity of petroleum hydrocarbons by the high-efficiency surfactant is 16562.66 mg / kg, which is 7595.40 mg / kg more than that of the low-efficiency surfactant.

[0042] exist Figure 3In Figure (b), the removal of TPH showed an increasing trend with increasing surfactant concentration, reaching its maximum at 4 hours. Specifically, under conditions of non-efficient surfactant concentrations of 5, 10, 15, and 20 g / L, the removal amounts of TPH were 3210.37 mg / kg, 6504.25 mg / kg, 11066.87 mg / kg, and 13425.80 mg / kg, respectively. However, when the surfactant concentration exceeded 15 g / L, the increase in TPH removal was not significant; therefore, 15 g / L can be considered the optimal concentration for non-efficient surfactants. Under this concentration condition, the removal of petroleum hydrocarbons by non-efficient surfactants increased with rinsing time: 2152.46 mg / kg in 0.5 to 1 hour; 3545.63 mg / kg in 1 to 2 hours; and only 1375.21 mg / kg in 2 to 3 hours. Therefore, 2 hours can be considered the optimal rinsing time for non-efficient surfactants.

[0043] Step 4: After rinsing the soil column with high-efficiency and low-efficiency surfactants, add isolated and purified Sphingomyelin-1, thus completing the process of surfactant-based combined bio-enhanced remediation of petroleum-contaminated soil.

[0044] Step 5, Bioremediation Experiment: Two treatment methods were designed: biostimulation and bioaugmentation. For the biostimulation treatment, nutrients were added to both the treated soil and the untreated control soil samples from the column experiment to promote the activity of indigenous microorganisms, thereby achieving natural soil remediation. On the other hand, the bioaugmentation treatment not only added nutrients to the treated soil but also introduced isolated and purified *Sphingobium* sp. 10 mL of *Sphingobium* sp. was added per 100 g of soil to enhance the degradation capacity of the microorganisms, thereby improving the remediation efficiency of oil-contaminated soil. A total of fifteen glass jars were used in the five biological experiments, and each experiment was repeated three times. Each jar contained 100 g of oil-contaminated soil from its respective treatment, with the soil moisture content maintained between 20% and 30%.

[0045] All treatments were supplemented with sodium dihydrogen phosphate (KH₂PO₄) and urea (CO(NH₂)₂) to final concentrations of 312.7 mg / kg nitrogen and 31.33 mg / kg phosphorus. Soil samples were collected every 7 days during this period to measure TPH, DOC, and NH₄⁺. + -N, NO3 - -N, NO2 - -N and the concentrations of total bacteria and petroleum-degrading bacteria.

[0046] The following measurement method verifies the performance of high-efficiency surfactants combined with bio-enhanced remediation of petroleum-contaminated soil.

[0047] Residual petroleum hydrocarbons in the soil were determined by gas chromatography with a flame ionization detector; changes in organic matter before and after leaching and after bioremediation were determined by three-dimensional fluorescence spectroscopy; changes in dehydrogenase, catalase, and trinitrile were determined by UV-Vis spectrophotometry; and the number and activity of microorganisms were analyzed by flow cytometry.

[0048] The present invention will be further illustrated below through specific embodiments.

[0049] Example 1 The surfactants used were APG IC911, APG 0810, and APG 0814. The total petroleum hydrocarbon content in the petroleum-contaminated soil was 48414.97 mg / kg. In the bottle experiment, the optimal concentration was 4 wt.%, the optimal washing time was 5 hours, the optimal water-to-soil ratio was 10:1, and the optimal pH was 7. In the column experiment, the optimal concentration was 15 g / L, the optimal washing time was 2 hours, and sodium dihydrogen phosphate (KH2PO4) and urea (CO(NH2)2) were added to all treatments, with final concentrations of 312.7 mg / kg for nitrogen and 31.33 mg / kg for phosphorus.

[0050] (1) Confirmation of high-efficiency surfactant through bottle test: APG IC911 and APG 0810 were compounded in pairs according to the optimal mass concentration of 4 wt.%, the optimal washing time of 5 hours, the optimal water-soil ratio of 10:1 and the optimal pH value of 7. Based on the removal efficiency, APG IC911 : APG 0810 = 6 : 4 was determined to be a high-efficiency surfactant.

[0051] (2) Determine the optimal concentration for surfactant elution column experiment: A column experiment was conducted at room temperature using APG IC911 : APG 0810 = 6 : 4 surfactant and 50 g of contaminated soil. Different concentrations (0, 5, 10, 15, 20 g / L) of surfactant solution were pumped into the column at a flow rate of 25 rpm using a peristaltic pump for elution. Samples were taken at pre-selected time points (0, 0.5, 1, 2, 3 and 4 hours) to evaluate its oil removal effect under pilot conditions.

[0052] (3) Bioremediation experiment: After the soil was washed with high-efficiency surfactant, it was dried and ground, and then sodium dihydrogen phosphate (KH2PO4) and urea (CO(NH2)2) were added to make the final concentration of nitrogen 312.7 mg / kg and phosphorus 31.33 mg / kg in the soil. The soil moisture content was maintained between 20% and 30%, and the local microorganisms were used to carry out the bioremediation experiment.

[0053] After the reaction was completed, the amount of petroleum hydrocarbons removed was 8831.53 mg / kg. (See attached image) Figure 10 Figure (a) in the middle.

[0054] Example 2 The surfactants used were APG IC911, APG 0810, and APG 0814. The total petroleum hydrocarbon content in the petroleum-contaminated soil was 48414.97 mg / kg. In the bottle experiment, the optimal concentration was 4 wt.%, the optimal washing time was 5 hours, the optimal water-to-soil ratio was 10:1, and the optimal pH was 7. In the column experiment, the optimal concentration was 15 g / L, the optimal washing time was 2 hours, and sodium dihydrogen phosphate (KH2PO4) and urea (CO(NH2)2) were added to all treatments, with final concentrations of 312.7 mg / kg for nitrogen and 31.33 mg / kg for phosphorus.

[0055] (1) Preparation of high-efficiency surfactant: APG IC911 and APG 0810 were compounded in pairs according to the optimal mass concentration of 4 wt.%, the optimal washing time of 5 hours, the optimal water-soil ratio of 10:1 and the optimal pH value of 7. Based on the removal efficiency, APG IC911 : APG 0810 = 6 : 4 was determined to be a high-efficiency surfactant.

[0056] (2) Surfactant elution column experiment: A high-efficiency surfactant was prepared and 50 g of contaminated soil was subjected to a column experiment at room temperature. Different concentrations (0, 5, 10, 15, 20 g / L) of surfactant solution were pumped into the soil at a flow rate of 25 rpm using a peristaltic pump for elution. Samples were taken at pre-selected time points (0, 0.5, 1, 2, 3 and 4 hours) to evaluate its oil removal effect under pilot-scale conditions. (3) Bioremediation experiment: After the soil was washed with high-efficiency surfactant, it was dried and ground, and then sodium dihydrogen phosphate (KH2PO4) and urea (CO(NH2)2) were added to make the final concentration of nitrogen 312.7 mg / kg and phosphorus 31.33 mg / kg in the soil. The soil moisture content was maintained between 20% and 30%. Bioremediation experiment was carried out using isolated and purified Sphingomonas sphingolipidae. 10 mL of Sphingomonas sphingolipidae was added to 100 g of soil.

[0057] After the reaction, the amount of petroleum hydrocarbons removed was 24642.39 mg / kg. (See attached image) Figure 5 Figure (a) in the middle.

[0058] Comparative Example 1 In the bioremediation experiment, sodium dihydrogen phosphate (KH2PO4) and urea (CO(NH2)2) were added to all treatments, with the final concentrations being 312.7 mg / kg for nitrogen and 31.33 mg / kg for phosphorus.

[0059] (1) Bioremediation experiment: After air-drying and grinding, oil-contaminated soil was mixed with sodium dihydrogen phosphate (KH2PO4) and urea (CO(NH2)2) to make the final concentration of nitrogen 312.7 mg / kg and phosphorus 31.33 mg / kg in the soil, and the soil moisture content was maintained between 20% and 30%. The bioremediation experiment was carried out using local microorganisms.

[0060] After the reaction, the amount of petroleum hydrocarbons removed was 2321.82 mg / kg. (See attached image) Figure 10 Figure (a)

[0061] Comparative Example 2 The surfactants used were APG IC911, APG 0810, and APG 0814. The total petroleum hydrocarbon content in the petroleum-contaminated soil was 48414.97 mg / kg. In the bottle experiment, the optimal concentration was 4 wt.%, the optimal washing time was 5 hours, the optimal water-to-soil ratio was 10:1, and the optimal pH was 7. In the column experiment, the optimal concentration was 15 g / L, the optimal washing time was 2 hours, and sodium dihydrogen phosphate (KH2PO4) and urea (CO(NH2)2) were added to all treatments, with final concentrations of 312.7 mg / kg for nitrogen and 31.33 mg / kg for phosphorus.

[0062] (1) Preparation of non-efficient surfactants: APG 0810 and APG 0814 were compounded in pairs according to the optimal mass concentration of 4 wt.%, the optimal washing time of 5 hours, the optimal water-soil ratio of 10:1 and the optimal pH value of 7. Based on the removal efficiency, APG 0810 : APG 0814 = 6 : 4 was determined to be a non-efficient surfactant.

[0063] (2) Surfactant elution column experiment: A non-efficient surfactant and 50 g of contaminated soil were prepared for column experiments at room temperature. Different concentrations (0, 5, 10, 15, 20 g / L) of surfactant solution were pumped into the soil at a flow rate of 25 rpm using a peristaltic pump for elution. Samples were taken at pre-selected time points (0, 0.5, 1, 2, 3 and 4 hours) to evaluate its oil removal effect under pilot-scale conditions. (3) Bioremediation experiment: After the soil was washed with non-efficient surfactants, it was air-dried and ground, and then sodium dihydrogen phosphate (KH2PO4) and urea (CO(NH2)2) were added to make the final concentration of nitrogen in the soil 312.7 mg / kg and phosphorus 31.33 mg / kg, and the soil moisture content was maintained between 20% and 30%. The bioremediation experiment was carried out using local microorganisms.

[0064] After the reaction, the amount of petroleum hydrocarbons removed was 4118.47 mg / kg. (See attached image) Figure 10 Figure (a)

[0065] Comparative Example 3 The surfactants used were APG IC911, APG 0810, and APG 0814. The total petroleum hydrocarbon content in the petroleum-contaminated soil was 48414.97 mg / kg. In the bottle experiment, the optimal concentration was 4 wt.%, the optimal washing time was 5 hours, the optimal water-to-soil ratio was 10:1, and the optimal pH was 7. In the column experiment, the optimal concentration was 15 g / L, the optimal washing time was 2 hours, and sodium dihydrogen phosphate (KH2PO4) and urea (CO(NH2)2) were added to all treatments, with final concentrations of 312.7 mg / kg for nitrogen and 31.33 mg / kg for phosphorus.

[0066] (1) Preparation of non-efficient surfactants: APG 0810 and APG 0814 were compounded in pairs according to the optimal mass concentration of 4 wt.%, the optimal washing time of 5 hours, the optimal water-soil ratio of 10:1 and the optimal pH value of 7. Based on the removal efficiency, APG 0810 : APG 0814 = 6 : 4 was determined to be a non-efficient surfactant.

[0067] (2) Surfactant elution column experiment: A non-efficient surfactant was prepared and 50 g of contaminated soil was subjected to a column experiment at room temperature. Different concentrations (0, 5, 10, 15, 20 g / L) of surfactant solution were pumped into the soil at a flow rate of 25 rpm using a peristaltic pump for elution. Samples were taken at pre-selected time points (0, 0.5, 1, 2, 3 and 4 hours) to evaluate its oil removal effect under pilot-scale conditions. (3) Bioremediation experiment: After the soil was washed with non-efficient surfactants, it was dried and ground, and then sodium dihydrogen phosphate (KH2PO4) and urea (CO(NH2)2) were added to make the final concentration of nitrogen 312.7 mg / kg and phosphorus 31.33 mg / kg in the soil. The soil moisture content was maintained between 20% and 30%. Bioremediation experiment was carried out using isolated and purified Sphingomyelin-1,000.

[0068] After the reaction, the amount of petroleum hydrocarbons removed was 18285.19 mg / kg. (See attached image) Figure 5 Figure (a)

[0069] Table 1. Comparison of Petroleum Hydrocarbon Removal Performance

[0070] Table 1 shows the TPH removal rates in different treatment groups after biostimulation and bioaugmentation. It can be seen that after 60 days of cultivation, the TPH degradation rate in contaminated soil with only added nutrients was only 2321.82 mg / kg. In contrast, the TPH degradation rates in contaminated soil after leaching with a non-efficient surfactant and after leaching with a highly efficient surfactant followed by nutrient addition increased to 4118.47 mg / kg and 8831.53 mg / kg, respectively. However, the biological removal of TPH did not increase significantly. Furthermore, the number of microorganisms remained almost unchanged in both the soil with only added nutrients and the soil with leaching with non-efficient and highly efficient surfactants followed by nutrient addition. Figure 10 (b) It is speculated that the relatively low number of indigenous microorganisms is the main reason for the relatively low degradation rate. Therefore, this invention employs a bioaugmentation strategy of further adding exogenous Bacillus to improve bioremediation efficiency, such as... Figure 5 As shown, from Figure 5 As shown in Figure (a), after 60 days of biodegradation experiments, the high-efficiency group achieved a biodegradation rate of 24642.39 mg / kg of TPH, significantly higher than the non-high-efficiency group's 18285.19 mg / kg. This may be because high-efficiency surfactants can influence the bioremoval efficiency of target pollutants by altering cell activity, growth rate, cell surface properties, and intracellular degrading enzyme activity. See also Figure 5 Figure (b) shows that, regarding carbon chain removal, both the high-efficiency and low-efficiency groups showed relatively low removal rates of long-chain components (C24–C30). Specifically, the high-efficiency and low-efficiency groups removed 3126.12 mg / kg and 2106.14 mg / kg of long-chain components (C24–C30), respectively. In contrast, the removal rates of short-chain components (C10–C16) and medium-chain components (C17–C23) were dominant in both groups. The high-efficiency and low-efficiency groups removed 9822.20 mg / kg and 7592.23 mg / kg of short-chain components (C10–C16), respectively, and 11694.07 mg / kg and 8586.82 mg / kg of medium-chain components (C17–C23), respectively. This phenomenon can be attributed to the fact that long-chain components, due to their longer molecular chains, have higher hydrophobicity and are more difficult for microorganisms to absorb and utilize, thus resulting in relatively low removal rates. from Figure 5As shown in Figure (c), during the 60-day degradation process, the TPH removal rate in the high-efficiency group was consistently higher than that in the low-efficiency group, especially during the periods of days 21-30 and 31-40, where the increase in removal rate in the high-efficiency group was more significant. From day 21-30, the TPH removal rate in the high-efficiency group was 6165.08 mg / kg, significantly higher than the 4855.45 mg / kg in the low-efficiency group; while from day 31-40, the TPH removal rate in the high-efficiency group was 5455.68 mg / kg, 1676.48 mg / kg more than the low-efficiency group. This result is consistent with... Figure 5 Corresponding to the changes in total bacterial count shown in figure a, the total bacterial count in the high-efficiency group was significantly higher than that in the non-high-efficiency group during days 21-30 and 31-40. With the significant increase in the abundance of hydrocarbon-degrading bacteria, TPH could be removed in large quantities.

[0071] Therefore, the application of surfactant rinsing combined with bio-enhancing provides a promising strategy for improving TPH degradation efficiency.

[0072] Furthermore, after leaching with highly efficient surfactants, the solubilizing effect of humic acid (HA) improved the bioavailability of alkanes. During bioremediation, the degradation rate constant of the highly efficient surfactant group (k = 0.02667 d) was [not specified in the original text]. -1 The efficiency of the TPH surfactant was 2.35 times that of the non-efficient group, and the degradation rate of TPH was significantly accelerated (half-life of only 26 days). This is attributed to the significant increase in the number and activity of microorganisms due to nutrient stimulation in the early stages of bioremediation, which promoted the production of more soil enzymes and thus accelerated the entire remediation process. Highly efficient surfactants can also serve as a stronger additional carbon source, accelerating the biodegradation process through a cometabolous pathway.

[0073] The efficient direct oxidation of petroleum hydrocarbons in soil by this invention can be seen from the following aspects: (1) Three-dimensional fluorescence analysis The surfactant combined with biofortification used in this invention enhances the fluorescence intensity of soil organic matter. Compared with the supernatant before surfactant leaching, leaching treatment with both high-efficiency and low-efficiency surfactants significantly increased the fluorescence intensity of humic acid substances (region V). Figure 6 (See Figures (a) and (f)). Specifically, before rinsing, the fluorescence intensity of humic acid compounds was 1.01 × 10⁷ AU. After rinsing with a non-highly effective surfactant, its fluorescence intensity increased to 1.93 × 10⁷ AU, an increase of 1.91 times; while after rinsing with a highly effective surfactant, its fluorescence intensity increased by 3.56 times, to 3.60 × 10⁷ AU. Figure 6(See Figure (f)). These results indicate that highly efficient surfactants can significantly increase the content of humic acid compounds. This increase not only improves the solubility of TPH but also enhances the accessibility of TPH to microorganisms. During bioremediation, the fluorescence intensity of humic acid compounds (region V) in the highly efficient group significantly increased in the later stage of remediation, reaching 5.651 × 10⁷ AU, which is 1.57 times that in the early stage of bioremediation and much higher than the 4.291 × 10⁷ AU in the non-highly efficient group. This significant increase in humic acid compounds can be attributed to the fact that more total petroleum hydrocarbons (TPH) in the highly efficient group were decomposed into smaller organic molecules by microorganisms. These smaller organic molecules further polymerized in subsequent processes to form humic acid compounds. (2) Nutrient analysis The surfactants used in this invention, combined with biofortification, enhance the consumption of soil nutrients in the high-efficiency group. In bioremediation, an adequate nutrient supply is crucial for maintaining the metabolic activity of microorganisms. This is achieved by comparing the changes in nutrient consumption between the high-efficiency and non-high-efficiency groups (see...). Figure 7 The study found that the degradation process exhibited distinct stages. In the initial degradation stage (0-10 days), the dissolved organic carbon (DOC) consumption of the high-efficiency group was similar to that of the low-efficiency group. However, in days 11-20 and 21-30, the consumption was significantly higher in the high-efficiency group than in the low-efficiency group (see [reference needed]). Figure 7 (Figure (a)). Specifically, during days 0-10, the DOC consumption in the high-efficiency group was 735.6 mg / kg, only 169.60 mg / kg higher than that in the low-efficiency group. However, during days 11-20 and 21-30, the DOC consumption in the high-efficiency group was 2867.60 mg / kg and 1730.00 mg / kg, respectively, while the low-efficiency group consumed only 2022.40 mg / kg and 1241.20 mg / kg. Furthermore, the changes in ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen consumption in the high-efficiency group were similar to those in DOC. These significant differences indicate that the microorganisms in the high-efficiency group exhibited higher metabolic efficiency and activity in degrading TPH.

[0074] (3) Analysis of microbial degradation capacity The surfactant combined with biofortification used in this invention results in a higher number and activity of microorganisms in the high-efficiency group. After surfactant leaching, the initial total bacterial counts in the high-efficiency and non-high-efficiency groups were not significantly different, at 3.36 and 3.14 log CFU / g soil, respectively. However, after 40 days of incubation, the total bacterial counts in both groups reached their peak, being 2.24 times and 1.76 times the initial counts, respectively, at 7.521 and 5.56 log CFU / g soil. Furthermore, in other stages of bioremediation (10 days, 20 days, 30 days, 50 days, and 60 days), the total bacterial count in the high-efficiency group was consistently higher than that in the non-high-efficiency group, being 1.18 times, 1.13 times, 1.25 times, 1.35 times, and 1.37 times higher, respectively. Figure 8 (See Figure (a)). Similarly, the percentage of viable bacteria in the high-efficiency group was also higher than that in the non-high-efficiency group during bioremediation, significantly increasing from 49.5% after rinsing to 78.4% after 60 days, a 32.9% increase compared to the non-high-efficiency group (45.5%). Figure 8 (See Figure (b)). This high-quantity and highly active microbial community provides a strong foundation for the degradation of petroleum hydrocarbons. However, the biodegradation rate and removal efficiency of petroleum hydrocarbons are also closely related to the enzyme activity of the total petroleum hydrocarbon-degrading microorganisms.

[0075] (4) Highly efficient surfactants serve as a stronger additional carbon source In soils biofortified with *Sphingomonas* sp., the biodegradation of total petroleum hydrocarbons (TPH) was significantly enhanced after 30 days of incubation with the addition of glucose (to provide an additional carbon source for microbial growth), non-efficient surfactants, and efficient surfactants. The biodegradation of TPH was 2.29 times, 2.71 times, and 3.53 times that of glucose, respectively, after the addition of efficient surfactants. Therefore, efficient surfactants significantly improved the biodegradation rate of TPH, showing better results than glucose and non-efficient surfactants. Compared to day 0, both glucose and surfactant groups showed an increase in bacterial count after remediation. On day 10, the number of microorganisms in the glucose-added samples was slightly higher than that in the surfactant-added samples, but on day 20, the number of microorganisms in the glucose-added samples decreased. In contrast, the number of microorganisms in the surfactant-added groups increased over time, and the number of microorganisms in the group with efficient surfactants was higher than that with non-efficient surfactants.

[0076] The experimental results above show that surfactants can promote the better function of *Sphingomonas sphingolipidae*. This is further demonstrated by measuring the three-dimensional excitation-emission matrix (3DEEM) spectra before and after surfactant rinsing. Figure 6Compared to the supernatant before surfactant rinsing, rinsing with both high-efficiency and low-efficiency surfactants significantly increased the fluorescence intensity of humic substances (region V). On the other hand, alkyl glycoside surfactants can serve as additional carbon sources to promote the growth of *Sphingomonas* and the degradation of petroleum hydrocarbons, with high-efficiency surfactants showing stronger effects than glucose and low-efficiency surfactants. Figure 9 As shown in Figure (a), in soil biofortified with *Sphingomonas* sp., the biodegradation of total petroleum hydrocarbons (TPH) was significantly enhanced after 30 days of incubation following the addition of glucose, a non-efficient surfactant, and a highly efficient surfactant. Specifically, in the soil sample with added glucose, the biodegradation of TPH on days 10, 20, and 30 were 489.31 mg / kg, 863.16 mg / kg, and 1225.61 mg / kg, respectively. In contrast, the biodegradation of TPH after adding the non-efficient surfactant was 1.32 times, 1.65 times, and 1.67 times that after adding glucose; while the biodegradation of TPH after adding the highly efficient surfactant was 2.29 times, 2.71 times, and 3.53 times that after adding glucose. Therefore, the highly efficient surfactant significantly improved the biodegradation rate of TPH, showing better results than glucose and the non-efficient surfactant. Compared to day 0, the number of bacteria increased in both the glucose and surfactant groups after remediation. Figure 9 As shown in Figure (b), on day 10, the number of microorganisms in the glucose-added samples was slightly higher than that in the surfactant-added samples. However, on day 20, the number of microorganisms in the glucose-added samples decreased, indicating that glucose addition can promote bacterial growth in the short term, but glucose is rapidly consumed by soil bacteria. In contrast, the number of microorganisms in the surfactant-added group increased over time, and the number of microorganisms in the group with high-efficiency surfactants was higher than that with low-efficiency surfactants.

[0077] This invention discloses a method for remediating petroleum-contaminated soil using a combination of highly efficient surfactants and bio-enhanced surfactants. A high-efficiency surfactant is prepared by mixing APG IC911 and APG 0810 in a 6:4 ratio in an Erlenmeyer flask. After the prepared high-efficiency surfactant is applied to column chromatography leaching, *Sphingomonas sphingolipidae* isolated and purified from the contaminated soil is added to achieve highly efficient removal of petroleum hydrocarbons from the soil. After 60 days of bioremediation, the total petroleum hydrocarbon removal rates for the high-efficiency group and the non-high-efficiency group were 85.11% and 56.29%, respectively. During the surfactant leaching stage, the high-efficiency group removed 16562.66 mg / kg of petroleum hydrocarbons, 7595.39 mg / kg more than the non-high-efficiency group. Furthermore, the high-efficiency group showed a significant increase in humic acid substances after leaching, which not only improved the solubility of TPH (total hydrochloric acid) but also enhanced the accessibility of TPH to microorganisms. In the bioremediation stage, the high-efficiency surfactant acts as a stronger additional carbon source, increasing the number and activity of microorganisms and promoting the production of more soil enzymes, thereby accelerating the entire remediation process. Therefore, surfactant leaching combined with biological treatment is an effective method for remediating petroleum hydrocarbon-contaminated soil.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for remediating petroleum-contaminated soil by surfactant in combination with bioaugmentation, characterized in that, The method comprises the following steps: S1, adding one or more alkyl glycoside surfactants to the soil contaminated by oil to leach the soil; the alkyl glycoside surfactant is a mixed solution of alkyl glycoside and water, and the soil is treated by adjusting the water-soil ratio; S2, adding Sphingomonas to the soil leached in S1 for biological strengthening repair; during the biological strengthening repair, the alkyl glycoside surfactant is used to provide a carbon source, promote the growth of Sphingomonas, increase the number and activity of microorganisms, and promote the production of soil enzymes.

2. The method for remediating petroleum contaminated soil by surfactant combined with bioaugmentation according to claim 1, characterized in that, In S1, the alkyl glycoside is one or more of APG IC911, APG 0810 and APG 0814.

3. The method for remediating petroleum contaminated soil by surfactant combined with bioaugmentation according to claim 2, characterized in that, In S1, the alkyl glycoside in the alkyl glycoside surfactant is APG IC911 and APG 0810 in a molar ratio of 6:

4.

4. The method for remediating petroleum contaminated soil by surfactant combined with bioaugmentation according to claim 1, characterized in that, The concentration of the alkyl glycoside surfactant in S1 is 5-20 g / L.

5. The method for remediating petroleum contaminated soil by surfactant combined with bioaugmentation according to claim 1, characterized in that, In S1, the water-soil ratio of the soil is (4-20):

1.

6. The method for remediating petroleum contaminated soil by surfactant combined with bioaugmentation according to claim 1, characterized in that, In S1, the leaching time is 1-7 h.

7. The method for remediating petroleum contaminated soil by surfactant combined with bioaugmentation according to claim 1, characterized in that, In S1, the pH value of the alkyl glycoside surfactant is 3-11.

8. The method for remediating petroleum contaminated soil by surfactant combined with bioaugmentation according to claim 1, characterized in that, In S2, sodium dihydrogen phosphate and urea are also added, so that the nitrogen content in the final soil is 312.7 mg / kg, and the phosphorus content is 31.33 mg / kg.

9. The method for remediating petroleum contaminated soil by surfactant combined with bioaugmentation according to claim 1, characterized in that, In S1, in the leaching step, the concentration of the alkyl glycoside surfactant solution is 15 g / L, the water-soil ratio is 10:1, the leaching time is 2 hours, and the pH value is 7.

10. The method for remediating petroleum contaminated soil by surfactant combined with bioaugmentation according to claim 1, characterized in that, In S2, 10 mL of Sphingomonas is added to 100 g of soil.

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