Petroleum hydrocarbon degrading bacterium, application thereof and oily sludge degrading method

Abstract

The invention belongs to the technical field of oily sludge degradation microbiology, and relates to a petroleum hydrocarbon degrading bacterium, application and an oily sludge degradation method. The petroleum hydrocarbon degrading bacterium is brevibacillus brevis, and the preservation number of the petroleum hydrocarbon degrading bacterium is CGMCC (China General Microbiological Culture Collection Center) No. 28749. The petroleum hydrocarbon degrading bacteria are extracted from the oily sludge, the extraction cost is low, and the method is simple and feasible. Petroleum hydrocarbon degrading bacteria are prepared into bacterial liquid with OD600 of 1, 50 mL of the bacterial liquid is sprayed to each kg of oily sludge, high-temperature aerobic fermentation is performed on the oily sludge under the aerobic conditions that the pH is 7-7.5 and the temperature is 50-70 DEG C, the oil removal rate reaches 38.2% within 7 days, the degradation effect is remarkable, and theoretical reference is provided for shortening the period of treating the oily sludge through a biological method and improving the treatment efficiency.

Description

Technical Field

[0001] This invention belongs to the field of microbiology technology for the degradation of oily sludge, specifically relating to a petroleum hydrocarbon degrading bacterium, its application in the degradation of oily sludge, and a method for the degradation of oily sludge. Background Technology

[0002] Oily sludge from petrochemical enterprises refers to the general term for hazardous solid waste mainly composed of petroleum components generated during petroleum refining, chemical processing, and wastewater treatment processes in petrochemical companies. Its main components are crude oil and related refined oil products, silt, and water, formed after thorough emulsification and mixing, resulting in a black, viscous colloid. Oily sludge from petrochemical enterprises is listed in the "National Hazardous Waste List," and its toxic and hazardous substances mainly include: organic compounds such as polycyclic aromatic hydrocarbons and polychlorinated biphenyls (PCBs); heavy metals such as copper, zinc, and cadmium; and salts. Without effective treatment, oily sludge from petrochemical enterprises will cause serious environmental harm. Currently, my country produces more than 5 million tons of oily sludge annually. With the expansion of petrochemical processing scale and the increasing heaviness and quality of crude oil, the production of oily sludge from petrochemical enterprises will continue to grow, and its properties will become increasingly complex, increasing the difficulty of treatment. Therefore, oily sludge generally faces the problems of rising disposal costs and increased environmental risks.

[0003] Currently, oily sludge treatment technologies are mainly divided into two categories: physicochemical methods and biological treatment methods. Physicochemical methods mainly include incineration, pyrolysis, solvent extraction, chemical demulsification, chemical thermal washing, and conditioning-mechanical separation technologies; biological treatment methods mainly include aerobic fermentation, land cultivation, and bioreactors. Physicochemical methods can effectively treat most oily sludge, but their essence is the transfer of pollutants from one environmental medium to another, and the resulting solid products still need to be disposed of as hazardous waste, which can easily cause secondary pollution. Biological treatment methods have the lowest cost among all technologies, and aerobic fermentation technology is completely environmentally friendly. Its principle is that microorganisms use petroleum in oily sludge as a carbon source to degrade it, ultimately mineralizing it completely and transforming it into harmless inorganic substances (CO2 and H2O).

[0004] Biological treatment methods are rarely used for oily sludge in petrochemical enterprises, mainly for the following reasons: Traditional aerobic fermentation technology is natural composting, where the microorganisms are primarily present in the oily sludge itself, resulting in poor petroleum degradation and high-temperature resistance. Natural composting relies solely on the heat generated by microorganisms decomposing organic matter to maintain temperature. Therefore, the fermentation system maintains a short period of high temperature, lacks specialized thermophilic bacteria, and the fermentation temperature is not high enough. Consequently, the fermentation cycle is long, system efficiency is low, and the volume reduction rate is low. These factors limit the application of biological treatment technology in oily sludge treatment. Summary of the Invention

[0005] The purpose of this invention is to address the problems of long fermentation cycles and low sludge reduction rates in existing biological treatment processes for oily sludge. This invention screens out thermophilic bacterial strains from oily sludge that have a degradation effect on petroleum hydrocarbons at high temperatures. These strains can rapidly decompose organic matter such as petroleum hydrocarbons in oily sludge under high-temperature aerobic fermentation conditions, shortening the treatment cycle of aerobic fermentation, improving treatment efficiency, and reducing treatment costs.

[0006] The first aspect of the present invention provides a petroleum hydrocarbon degrading bacterium, namely Bevibacillus brevis, named BHYJ-9, with accession number CGMCC No. 28749.

[0007] A second aspect of the present invention provides the application of the aforementioned petroleum hydrocarbon degrading bacteria in the degradation of oily sludge.

[0008] A third aspect of the present invention provides a method for degrading oily sludge, comprising the following steps: contacting the petroleum hydrocarbon degrading bacteria with the oily sludge.

[0009] The beneficial effects of this invention include:

[0010] (1) This invention isolates and screens a highly efficient petroleum hydrocarbon degrading bacterium, BHYJ-9, from oily sludge. This bacterium is *Brevibacillus brevis*. The bacterium is then processed into OD... 600 A bacterial solution of 1 was added at a rate of 50 mL per kg of oily sludge. The oily sludge was subjected to high-temperature aerobic fermentation under aerobic conditions of pH 7–7.5 and temperature 50–70℃. After 7 days, the oil removal rate of the oily sludge reached 38.2%, demonstrating a significant effect in removing petroleum hydrocarbons. This invention provides a novel thermophilic bacterial strain for degrading petroleum hydrocarbons, offering a theoretical reference for high-temperature microbial aerobic fermentation treatment of oily sludge. Compared to conventional biological treatment processes, the fermentation temperature is significantly increased, and the treatment cycle is greatly shortened.

[0011] (2) The present invention extracts petroleum hydrocarbon degrading bacteria from oily sludge produced by petrochemical enterprises. The extraction cost is low and the method is simple and feasible.

[0012] (3) This invention investigated the effects of different temperature conditions and different amounts of BHYJ-9 bacterial agent on the degradation of oily sludge by strain BHYJ-9, providing an application reference for the treatment of oily sludge by strain.

[0013] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0014] Exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0015] Figure 1 The community morphology of strain BHYJ-9;

[0016] Figure 2 This is a scanning electron microscope image of strain BHYJ-9;

[0017] Figure 3 This is a graph showing the change in oil content of the oily sludge in Example 3.

[0018] Biological Preservation Instructions

[0019] The Bevibacillus brevis BHYJ-9 of this invention was deposited on October 25, 2023, at the China General Microbiological Culture Collection Center (Address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, Postcode 100101) (abbreviation of depositary institution: CGMCC), accession number CGMCCNo. 28749. Detailed Implementation

[0020] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0021] This invention uses oily sludge generated by petrochemical enterprises as raw material, screens and isolates thermophilic strains that can efficiently degrade petroleum hydrocarbons, and provides a method for degrading oily sludge using the strains.

[0022] The petroleum hydrocarbon degrading bacteria provided in this invention are *Brevibacillus* sp., named BHYJ-9, and are currently deposited at the China General Microbiological Culture Collection Center (CGMCC) of the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Beichen West Road, Chaoyang District, Beijing, China. The deposit date is October 25, 2023, and the accession number is CGMCC No. 28749. The classification name is *Brevibacillus brevis*.

[0023] The above-mentioned bacterial strains were isolated from oily sludge. This oily sludge was extracted from the wastewater pool of a petrochemical company's wastewater treatment workshop.

[0024] The present invention provides a method for screening and isolating the petroleum hydrocarbon-degrading bacterium BHYJ-9, comprising the following steps:

[0025] (1) Weigh 1g of oily sludge sample, add it to 250mL of sterile water, place it on a shaker, and shake and incubate it for 3h at a speed of 150r / min and 60℃.

[0026] (2) Using a pipette, take 5 mL of the supernatant and transfer it to 100 mL of petroleum enrichment liquid culture medium with a crude oil concentration of 1 g / L. Place the medium on a shaker and culture at 150 r / min and 60 °C for 5 days. Take another 5 mL of enrichment culture medium and transfer it to 100 mL of petroleum enrichment liquid culture medium. Keep other culture conditions unchanged, and increase the crude oil concentration of the culture medium by 1 g / L each time. Repeat this enrichment process 5 times.

[0027] (3) Take the bacterial culture that has undergone multiple consecutive incubations and perform 10, 10... 2 10 3 10 4 10 5 Dilute the solution by 1:1, and then spread 20 μL of each dilution onto petroleum-enriched solid medium. Incubate at 60°C for 2–3 days, observing the colony morphology, size, and color until purified colonies with a uniform morphology are formed. Inoculate these purified colonies onto slant solid medium and store them at 4°C for later use.

[0028] The components of the petroleum enrichment liquid culture medium used in this invention are: K2HPO4 7.3g / L, KH2PO4 2.42g / L, NaCl 2g / L, (NH4)2SO4 2g / L, MgSO4 0.3g / L, CaCl2 0.03g / L, trace element concentrate 1mL / L, a certain amount of crude oil, and 1L of water; pH 7.0, sterilized at 121℃ for 25min.

[0029] The components of the petroleum enrichment solid culture medium used in this invention are: K2HPO4 7.3 g / L, KH2PO4 2.42 g / L, NaCl 2 g / L, (NH4)2SO4 2 g / L, MgSO4 0.3 g / L, CaCl2 0.03 g / L, trace element concentrate 1 mL / L, and water 1 L; pH 7.0, sterilized at 121℃ for 25 min; add 15-20 g / L agar powder, sterilize at 121℃ for 25 min, and when the temperature drops to 50℃, shake well and pour into sterile plates. After cooling and solidification, drop 50 μL of crude oil onto the surface and spread evenly before use.

[0030] The components of the trace element concentrate used in this invention are: ZnSO4·7H2O 0.44 g / L, CuSO4·5H2O 0.20 g / L, MnSO4·2H2O 0.17 g / L, Na2MoO4·2H2O 0.06 g / L, H3BO3 0.10 g / L, and CoCl2·6H2O 0.08 g / L.

[0031] The petroleum hydrocarbon degrading bacterium BHYJ-9 of this invention has round colonies with irregular edges, white color, and is opaque. The colony surface is relatively smooth and raised, and Gram staining results indicate that it is a Gram-negative bacterium. Identification and sequence analysis of the 16S rDNA of this strain (nucleotide sequence shown in Seq IDNo:1) indicate that this strain belongs to the genus *Brevibacillus* sp.

[0032] The present invention also provides the application of the above-mentioned petroleum hydrocarbon degrading bacteria in the degradation of oily sludge.

[0033] Furthermore, the present invention provides a method for degrading oily sludge, comprising the following steps: contacting the petroleum hydrocarbon degrading bacteria with the oily sludge.

[0034] According to one specific embodiment of the present invention, the contact conditions include a temperature of 50–70°C and a pH of 7–7.5. Under these conditions, the petroleum hydrocarbon-degrading bacteria can efficiently degrade oily sludge.

[0035] According to a specific embodiment of the present invention, the method for the degradation of oily sludge by the petroleum hydrocarbon degrading bacteria is carried out according to the following steps:

[0036] (1) Activation of strain: The petroleum hydrocarbon degrading bacteria are inoculated into liquid culture medium and cultured at constant temperature with shaking until the logarithmic growth phase to prepare bacterial solution;

[0037] (2) Degradation of oily sludge: The bacterial solution is evenly sprayed into the oily sludge and high-temperature aerobic fermentation is carried out at 50-70℃ to degrade the petroleum hydrocarbons in the oily sludge.

[0038] In step (1), the culture medium can be a conventional culture medium used in the field for Bacillus brevis. In one specific embodiment of the present invention, the culture medium is LB medium. The components of the LB liquid culture medium used in the present invention are: 10 g / L tryptone, 5 g / L yeast extract, 10 g / L NaCl, and 1 L water; pH 7.0, sterilized at 121°C for 25 min.

[0039] In step (1), the purpose of the isothermal oscillation is to activate the strain. The preferred conditions include: a temperature of 55-65°C, a rotation speed of 100-200 r / min, and a time of 30-40 h.

[0040] For the petroleum hydrocarbon degrading bacteria of the present invention, the spraying dosage is 10 viable bacteria per kg of oily sludge. 10 ~10 12 CFU-based bacterial solutions can achieve good degradation effects on oily sludge. Specifically, the viable bacteria count can be 1×10⁻⁶. 10 CFU, 2×10 10CFU, 3×10 10 CFU, 4×10 10 CFU, 5×10 10 CFU, 6×10 10 CFU, 7×10 10 CFU, 8×10 10 cfu, 9×10 10 CFU, 1×10 11 CFU, 2×10 11 CFU, 3×10 11 CFU, 4×10 11 CFU, 5×10 11 CFU, 6×10 11 CFU, 7×10 11 CFU, 8×10 11 cfu, 9×10 11 CFU, 1×10 12 A value within the range of any one or any two of the above values ​​in CFU. According to a specific embodiment of the present invention, after the strain is activated, the OD value is adjusted... 600 The value is 1, and then it is evenly sprayed into the oily sludge. The spraying amount can be 10-500 mL of bacterial solution per kg of oily sludge, preferably 30-100 mL of bacterial solution, and more preferably 30-50 mL of bacterial solution.

[0041] According to a preferred embodiment of the present invention, the high-temperature aerobic fermentation step (2) includes: uniformly stirring the oily sludge after spraying the bacterial solution under aerobic conditions of pH 7-7.5 and temperature 50-70°C. The stirring time can be determined as needed, for example, 5-7 days, which can efficiently degrade petroleum hydrocarbons in the oily sludge.

[0042] According to one embodiment of the present invention, the oily sludge refers to oily sludge from petrochemical enterprises.

[0043] The present invention will be further described below with reference to the embodiments, but the scope of the present invention is not limited to these embodiments.

[0044] Example 1: Screening and isolation of strain BHYJ-9

[0045] The oily sludge in this invention is extracted from the oily sludge in the sewage pool of a petrochemical enterprise's wastewater treatment workshop.

[0046] Specific steps:

[0047] (1) Weigh 1g of oily sludge sample and add it to 250mL of sterile water. Place it on a shaker and culture it at 150r / min and 60℃ for 3h.

[0048] (2) Using a pipette, take 5 mL of the supernatant and transfer it to 100 mL of petroleum enrichment liquid culture medium with a crude oil concentration of 1 g / L. Place the medium on a shaker and culture at 150 r / min and 60 °C for 5 days. Take another 5 mL of enrichment culture medium and transfer it to 100 mL of petroleum enrichment liquid culture medium. Keep other culture conditions unchanged, and increase the crude oil concentration of the culture medium by 1 g / L each time. Repeat this enrichment process 5 times.

[0049] (3) Take the bacterial culture that has undergone multiple consecutive incubations and perform 10, 10... 2 10 3 10 4 10 5 Dilute the solution by 20 times, then spread 20 μL of each dilution onto petroleum-enriched solid medium. Incubate at 60℃ for 2–3 days, observing colony morphology, size, and color until purified colonies with a uniform morphology are formed. Finally, a strain BHYJ-9 with highly efficient petroleum hydrocarbon degradation capability is obtained. The streak plate diagram is shown below. Figure 1 As shown.

[0050] The components of the petroleum enrichment liquid culture medium are: K2HPO4 7.3g / L, KH2PO4 2.42g / L, NaCl 2g / L, (NH4)2SO4 2g / L, MgSO4 0.3g / L, CaCl2 0.03g / L, trace element concentrate 1mL / L, a certain amount of crude oil, and 1L of water; pH 7.0, sterilized at 121℃ for 25min.

[0051] The components of the petroleum enrichment solid culture medium are: K2HPO4 7.3g / L, KH2PO4 2.42g / L, NaCl 2g / L, (NH4)2SO4 2g / L, MgSO4 0.3g / L, CaCl2 0.03g / L, trace element concentrate 1mL / L, and water 1L; pH 7.0, sterilized at 121℃ for 25min; add 15-20g / L agar powder, sterilize at 121℃ for 25min, and when the temperature drops to 50℃, shake well and pour into sterile plates. After cooling and solidification, drop 50μL of crude oil onto the surface and spread evenly before use.

[0052] The components of the trace element concentrate are: ZnSO4·7H2O 0.44 g / L, CuSO4·5H2O 0.20 g / L, MnSO4·2H2O 0.17 g / L, Na2MoO4·2H2O 0.06 g / L, H3BO3 0.10 g / L, and CoCl2·6H2O 0.08 g / L.

[0053] Example 2: Morphological observation, physiological and biochemical experiments and DNA identification of strain BHYJ-9

[0054] (1) The selected dominant strains were isolated and purified, and subjected to Gram staining, microscopic observation, and electron microscopy. Morphological observation revealed that strain BHYJ-9 had round colonies with irregular edges, was white in color, opaque, and had a relatively smooth and convex surface. Electron microscopy showed that the strain was rod-shaped, as shown in the scanning electron microscope image below. Figure 2 Gram staining results indicated that it was a Gram-negative bacterium.

[0055] (2) Experiments were conducted according to the identification items and methods in Bergey's Manual of Bacterial Identification (8th Edition) and the Manual of Systematic Identification of Common Bacteria (Dong Xiuzhu et al., 2001). Physiological and biochemical characteristics are shown in Table 1.

[0056] Table 1. Physiological and biochemical characteristics of strain BHYJ-9

[0057] Physiological and biochemical reactions result Starch hydrolysis + Methyl red -

[0058] Note: "+" indicates positive, and "-" indicates negative.

[0059] (3) 16S rDNA sequencing was performed on strain BHYJ-9, and its nucleotide sequence is shown in Seq IDNo:1. BLAST alignment of the obtained 16S rDNA sequence indicated that the strain belongs to the genus *Brevibacillus* sp. It is currently deposited at the China General Biotechnology Center (CGMCC), Institute of Microbiology, Chinese Academy of Sciences, No. 3, Beichen West Road, Chaoyang District, Beijing, China, on October 25, 2023, with accession number CGMCCNo. 28749. The suggested classification and nomenclature is *Brevibacillus brevis*.

[0060] The formula for calculating the oil removal rate in this invention is as follows:

[0061] Oil removal rate (%) = ((M1×C1-M2×C2) / M1×C1)×100%

[0062] Where M1 is the mass of untreated oily sludge, C1 is the oil content of untreated oily sludge, M2 is the mass of treated oily sludge, and C2 is the oil content of treated oily sludge.

[0063] In the following examples and comparative examples, the oil content of the untreated oily sludge was 14.0%.

[0064] Example 3: Application of strain BHYJ-9 in the degradation of oily sludge

[0065] Petroleum hydrocarbon degrading bacteria BHYJ-9 was inoculated from an slant plate into LB liquid medium and cultured at 60℃ with constant temperature shaking at 150 rpm for 30–40 h until the logarithmic growth phase was reached. OD was then adjusted.600 A value of 1 is used to prepare bacterial solution.

[0066] The above-mentioned bacterial solution was evenly sprayed onto the oily sludge at a rate of 50 mL per kg of oily sludge. The oily sludge was uniformly stirred under aerobic conditions at pH 7–7.5 and temperature 50–70℃. Samples were taken every 1–2 days for 7 days. The dry basis oil content was determined using the "Test Methods for Sludge from Urban Wastewater Treatment Plants" (CJ / T 221-2005) to investigate the degradation effect of the bacterial strain on petroleum hydrocarbons. The changes in oil content of the oily sludge are shown in [Figure showing changes in oil content]. Figure 3 The degradation results showed that within 7 days, the strain could reduce the oil content of oily sludge from 14.0% to 9.1%, with an oil removal rate of 38.2%, demonstrating a significant degradation effect.

[0067] Comparative Example 1: Oil Removal Effect of BHYJ-9 on Oily Sludge under Different Temperature Conditions

[0068] Petroleum hydrocarbon degrading bacteria BHYJ-9 was inoculated from an slant plate into LB liquid medium and cultured at 60℃ with constant temperature shaking at 150 rpm for 30–40 h until the logarithmic growth phase was reached. OD was then adjusted. 600 A value of 1 is used to prepare bacterial solution.

[0069] The above-mentioned bacterial solution was evenly sprayed onto the oily sludge at a rate of 50 mL per kg of oily sludge. The oily sludge after spraying was uniformly stirred under aerobic conditions with a pH of 7–7.5 and temperatures of 30–50℃ and 70–90℃, respectively. After 7 days, the dry basis oil content was determined using the "Test Method for Sludge from Urban Wastewater Treatment Plants" (CJ / T 221-2005).

[0070] The degradation results showed that after 7 days, the oil content of the oily sludge was 10.7% and 10.1%, respectively, and the oil removal rate was 26.1% and 30.7%, respectively. It can be seen that the degradation effect was best at a temperature of 50-70℃.

[0071] Comparative Example 2: Oil Removal Effect of BHYJ-9 on Oily Sludge under Different Addition Amounts of BHYJ-9 Bacterial Solution

[0072] Petroleum hydrocarbon degrading bacteria BHYJ-9 was inoculated from an slant plate into LB liquid medium and cultured at 60℃ with constant temperature shaking at 150 rpm for 30–40 h until the logarithmic growth phase was reached. OD was then adjusted. 600 A value of 1 is used to prepare bacterial solution.

[0073] The above-mentioned bacterial solution was evenly sprayed onto the oily sludge. The spraying amounts were 20 mL, 30 mL, 40 mL, 60 mL, and 70 mL per kg of oily sludge. The oily sludge after spraying was uniformly stirred under aerobic conditions with a pH of 7–7.5 and a temperature of 50–70℃. After 7 days, the dry basis oil content was determined using the "Test Method for Sludge from Urban Wastewater Treatment Plants" (CJ / T 221-2005).

[0074] The degradation results showed that after 7 days, the oil content of the oily sludge was 12.1%, 10.1%, 9.8%, 10.3%, and 11.1%, respectively, and the oil removal rates were 15.1%, 30.7%, 33.0%, 29.5%, and 23.3%, respectively. It can be seen that the amount of BHYJ-9 bacterial solution added is 30-50 mL, especially 50 mL, which has better degradation efficiency.

[0075] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0076] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A petroleum hydrocarbon degrading bacterium, characterized in that, The petroleum hydrocarbon degrading bacteria is *Brevibacillus brevis*, with accession number CGMCC No. 28749.

2. The application of the petroleum hydrocarbon degrading bacteria according to claim 1 in the degradation of oily sludge.

3. A method for degrading oily sludge, comprising the following steps: The petroleum hydrocarbon degrading bacteria described in claim 1 are brought into contact with oily sludge.

4. The method for degrading oily sludge according to claim 3, wherein, The contact conditions include a temperature of 50–70°C and a pH of 7–7.

5.

5. The method for degrading oily sludge according to claim 3, wherein, The method includes the following steps: (1) Activation of strain: The petroleum hydrocarbon degrading bacteria are inoculated into liquid culture medium and cultured at constant temperature with shaking until the logarithmic growth phase to prepare bacterial solution; (2) Degradation of oily sludge: The bacterial solution is evenly sprayed into the oily sludge and high-temperature aerobic fermentation is carried out at 50-70℃ to degrade the petroleum hydrocarbons in the oily sludge.

6. The method for degrading oily sludge according to claim 5, wherein, In step (1), the culture medium is LB medium.

7. The method for degrading oily sludge according to claim 5, wherein, In step (1), the conditions for constant temperature oscillation include: temperature of 55-65℃, rotation speed of 100-200r / min, and time of 30-40h.

8. The method for degrading oily sludge according to claim 5, wherein, In step (2), the spraying rate is 10 live bacteria per kg of oily sludge. 10 ~10 12 CFU bacterial solution.

9. The method for degrading oily sludge according to claim 5, wherein, In step (2), the high-temperature aerobic fermentation step includes: uniformly stirring the oily sludge after spraying the bacterial solution under aerobic conditions of pH 7-7.5 and temperature 50-70℃.

10. The method for degrading oily sludge according to any one of claims 3-9, wherein, The oily sludge in question is oily sludge from petrochemical enterprises.

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