Combined remediation method for petroleum-contaminated soil

Abstract

The invention provides a combined remediation method for petroleum-contaminated soil. The method comprises the steps that urea peroxide, sodium carbonate and to-be-treated petroleum-contaminated soil are evenly mixed and react at the room temperature under the condition that the water-to-soil ratio is 1: 1-1: 4, and based on the mass of the to-be-treated petroleum-contaminated soil being 100%, the adding amount of urea peroxide is 1%-3%; the molar ratio of urea peroxide to sodium carbonate is 1: 1-5: 1; a microbial agent is added into the reacted soil, and microbial remediation is conducted under the condition that the soil humidity is 20%-50%; wherein the microbial agent is biochar-loaded mixed bacteria, the mixed bacteria comprise pseudomonas aeruginosa, acinetobacter venetii, bacillus flexus, bacillus aryabhattai and bacillus megatherium, and the particle size of the biochar is 30-80 meshes; the adding amount of the microbial agent is 1%-5% by taking the mass of the to-be-treated petroleum-contaminated soil as 100%.

Description

Technical Field

[0001] The invention relates to a combined restoration method for petroleum-contaminated soil. Background Art

[0002] During the process of oil extraction, transportation and storage, the leakage of oil and its products will cause soil and groundwater pollution to varying degrees. Oil is a mixture of carbon, hydrogen and a small amount of other elements. Oil that enters the water will form a thin film on the water surface that prevents light from penetrating, affecting the normal life activities of plants and animals in the water. Oil that enters the soil will make the soil hydrophobic and reduce permeability, destroying the soil microecological environment. They can evaporate from the soil into the air, migrate to underground aquifers, and enter the human body or animal and plant bodies through breathing, skin contact, eating and other methods. The polycyclic aromatic hydrocarbons in them have toxic effects such as carcinogenicity, teratogenicity and mutagenicity. Therefore, the remediation of oil-contaminated soil is urgent.

[0003] The remediation of petroleum-contaminated soil has always been the focus of scholars' research. Existing remediation technologies are mainly divided into physical, chemical and biological methods. Among them, microbial remediation has the characteristics of no secondary pollution and low cost, and has become one of the most widely studied and applied methods. However, the degradation effect of single microbial remediation on petroleum substances with complex structures and tightly adsorbed in soil organic matter is poor. At the same time, the remediation process will be affected by various factors such as ambient temperature and soil pH, making its remediation effect unstable. In order to overcome the above shortcomings, researchers have tried to combine chemical oxidation with microbial remediation technology in recent years. The single chemical oxidation technology has a strong effect and a fast effect time, which is especially suitable for complex and difficult-to-degrade compounds. However, the single chemical oxidation method uses a large amount of reagents. Studies have shown that high concentrations of oxidants will have a certain impact on indicators such as soil pH and organic matter content, causing damage to the soil environment. Combining chemical oxidation technology with microbial remediation can not only solve the problem of microorganisms being difficult to degrade complex hydrocarbons, but also solve the problem of large amounts of chemical oxidants and high hazards. It is a soil remediation technology with research potential. For example, CN106811205A discloses a method for remediating petroleum hydrocarbon contaminated soil by coupling persulfate with indigenous microbial stimulation, in which ammonium phosphate and ammonium hydrogen phosphate are added as nitrogen sources to regulate the nutrient source of microorganisms after chemical oxidation with persulfate. For example, CN105772499A discloses an in-situ combined remediation method for petroleum contaminated site soil, in which after chemical oxidation with chemical oxidant sodium persulfate and activator, additional microbial nutrients are added to control the carbon-nitrogen ratio.

[0004] Currently, the methods combining chemical oxidation technology with microbial remediation generally have the problem that chemical oxidation and microbial remediation work independently, the coordination effect between the two is poor, and the removal rate of petroleum hydrocarbons is not high. Summary of the invention

[0005] The object of the present invention is to provide a soil remediation method which has good coordination effect of chemical oxidation and microbial remediation and can effectively remove petroleum hydrocarbons in petroleum-contaminated soil with a high removal rate.

[0006] In order to achieve the above object, the present invention provides a method for combined remediation of petroleum-contaminated soil, wherein the method comprises:

[0007] The urea peroxide, activator and the petroleum contaminated soil to be treated are mixed and reacted at room temperature under the condition of a water-soil ratio of 1:1-1:4; wherein the activator is a 2- wherein, based on the mass of the petroleum-contaminated soil to be treated as 100%, the amount of urea peroxide added is 1%-3%; urea peroxide and CO3 provided by the activator 2- The molar ratio is 1:1-5:1;

[0008] Add a microbial agent to the reacted soil, and perform microbial remediation under the condition of soil moisture of 20%-50%; wherein the microbial agent is a biochar-loaded mixed bacteria agent, the mixed bacteria include Pseudomonas aeruginosa, Acinetobacter venetianus, Bacillus flexus, Bacillus aryabhattai and Bacillus megaterium, the particle size of the biochar is 30-80 mesh; the effective viable bacteria count of the biochar-loaded mixed bacteria agent is ≥1.6×10 9 CFU / g; based on the mass of the petroleum-contaminated soil to be treated as 100%, the amount of microbial agent added is 1%-5%.

[0009] In the combined remediation method for petroleum-contaminated soil provided by the present invention, CO3 2- Activate urea peroxide and combine with specific types of microorganisms to repair contaminated soil. 2- Activated urea peroxide can effectively degrade petroleum hydrocarbons in the soil and enhance the degradation capacity of specific microbial agents added later on. 2- The larger amount of activated urea peroxide degraded the heaviest component colloid, providing a better repair environment for microbial degradation, thereby achieving effective coordination between chemical oxidation and microbial repair, achieving the effect of 1+1>2.

[0010] In the combined remediation method for petroleum-contaminated soil provided by the present invention, a specific type of microbial agent is used with biochar as a carrier. The presence of the biochar carrier helps to shield harsh environmental conditions, improve microbial activity and enzyme activity through its adsorption effect, provide nutrients for microorganisms, and increase the transfer rate of oxygen and water molecules in the soil.

[0011] According to the above-mentioned combined remediation method for petroleum-contaminated soil, preferably, sodium carbonate is selected as the activator.

[0012] According to the above-mentioned combined remediation method for petroleum-contaminated soil, preferably, the volume ratio of Pseudomonas aeruginosa, Acinetobacter venezuelae, Bacillus flexus, Bacillus aryabordoi, and Bacillus megaterium is 3-6:4-7:1-3:1-3:1.

[0013] According to the above-mentioned combined remediation method for petroleum-contaminated soil, preferably, the microbial agent is prepared by the following method:

[0014] Pseudomonas aeruginosa, Acinetobacter venezuelae, Bacillus flexus, Bacillus aryabordoi, and Bacillus megaterium are mixed (for example, in a volume ratio of 3:6:1:1:1) to obtain a mixed bacteria;

[0015] The mixed bacteria are transferred to a mixture of biochar and culture medium for cultivation, so that the mixed bacteria are fixed on the biochar;

[0016] After the fixing process is completed, the microbial agent is obtained through drying.

[0017] According to the above-mentioned combined remediation method for petroleum-contaminated soil, preferably, the petroleum-contaminated soil to be treated is prepared by the following method:

[0018] crushing and screening the petroleum contaminated soil to obtain the petroleum contaminated soil to be treated;

[0019] More preferably, the sieving is through a 10-20 mesh sieve.

[0020] According to the above-mentioned combined remediation method for petroleum-contaminated soil, preferably, the petroleum hydrocarbon content in the petroleum-contaminated soil to be treated does not exceed 50,000 mg / kg (based on the mass of the petroleum-contaminated soil to be treated), for example, 10,000 mg / kg-50,000 mg / kg.

[0021] According to the above-mentioned combined remediation method for petroleum-contaminated soil, preferably, the reaction time is 1-4 days.

[0022] According to the above-mentioned combined remediation method for petroleum-contaminated soil, preferably, a nutrient source is added to the soil after the reaction while adding a microbial agent;

[0023] More preferably, the nutrient source includes a potassium source and humic acid;

[0024] Further preferably, the potassium source is potassium dihydrogen phosphate;

[0025] More preferably, based on the mass of the petroleum-contaminated soil to be treated as 100%, the amount of potassium dihydrogen phosphate added is 0.1%-0.2%, and the amount of humic acid added is 0.1%-0.5%.

[0026] According to the above-mentioned combined remediation method for petroleum-contaminated soil, preferably, the time for microbial remediation is 30 days to 50 days.

[0027] The technical solution provided by the present invention uses a specific type of oxidant carbamide peroxide and an activator to provide CO3 2- The soil is treated with compounds, which can provide a suitable environment for subsequent treatment with specific types of microbial agents while achieving soil chemical oxidation remediation, effectively stimulate and strengthen the soil remediation ability of subsequent specific types of microbial agents, achieve effective coordination between chemical oxidation and microbial remediation, achieve the effect of 1+1>2, and effectively remove petroleum hydrocarbons in petroleum-contaminated soil. Compared with the existing technology, it has the following beneficial effects:

[0028] 1. The technical solution provided by the present invention utilizes chemical oxidation in combination with microbial remediation to remove petroleum hydrocarbons from petroleum-contaminated soil, and its petroleum hydrocarbon removal rate is greater than the sum of the chemical oxidation petroleum hydrocarbon removal rate and the microbial remediation petroleum hydrocarbon removal rate.

[0029] 2. The technical solution provided by the present invention uses carbamide peroxide as an oxidant and can provide CO3 2- Compounds such as sodium carbonate are used as activators to treat the soil, which can provide a suitable environment for subsequent treatment with specific types of microbial agents while achieving soil chemical oxidation remediation, and can effectively stimulate and enhance the soil remediation ability of subsequent specific types of microbial agents. 2- The hydrogen peroxide, urea and active oxygen released during soil treatment can not only remove difficult-to-degrade petroleum pollutants but also regulate soil nutrition, provide electron donors for microorganisms, improve soil biodegradability, and activate the ability of microorganisms to metabolize petroleum pollutants.

[0030] 3. The technical solution provided by the present invention has simple process, convenient operation, low cost of chemical reagent raw materials and is easy to transport.

[0031] 4. The technical solution provided by the present invention uses less oxidant and has a high removal rate of petroleum hydrocarbon pollutants, which can reduce the cost of repair and the risk of secondary pollution.

[0032] 5. The technical solution provided by the present invention is suitable for in-situ or ex-situ remediation of petroleum-contaminated soil and has little impact on the surrounding environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a diagram showing the petroleum hydrocarbon removal effect of the repair methods provided in Example 1, Comparative Example 1, Comparative Example 5, and Comparative Example 6.

[0034] Figure 2 This is a diagram showing the effect of petroleum hydrocarbon removal rate of the repair methods provided in Example 1 and Comparative Examples 1 to 6. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0036] Preparation Example 1

[0037] Preparation of petroleum contaminated soil to be treated: The petroleum contaminated soil (petroleum hydrocarbon content is about 45000 mg / kg) is crushed and sieved (passed through a 10-mesh sieve) to obtain the petroleum contaminated soil to be treated, which is stored in a -20°C refrigerator for later use.

[0038] Preparation Example 2

[0039] Preparation of microbial inoculants:

[0040] Pseudomonas aeruginosa, Acinetobacter venetianus, Bacillus flexus, Bacillus aryabhattai, and Bacillus megaterium were cultured respectively; specifically, the bacteria to be cultured were inoculated with LB medium (LB medium including 10 g / L tryptone, 5 g / L yeast extract, 10 g / L sodium chloride, pH 7.0) at an inoculum amount of 10 wt%, and cultured in a shaker (temperature 30 ° C, speed 150 r min -1 , time is 24h); then transferred to another LB medium with an inoculum of 10wt% and cultured under the same conditions for 30h; then placed in a centrifuge tube, centrifuged at 8000r / min in a high-speed centrifuge for 30min, poured out the supernatant, added sterile saline and shook evenly, centrifuged again at 8000r / min for 30min, poured out the supernatant, added sterile saline and shook evenly for standby use;

[0041] The cultured Pseudomonas aeruginosa, Acinetobacter venetianus, Bacillus flexus, Bacillus aryabhattai, and Bacillus megaterium are mixed in a volume ratio of 3:6:1:1:1 to obtain a mixed bacteria;

[0042] The mixed bacteria were transferred to the mixture of biochar and LB broth at a loading rate of 10wt% (wherein the mass content of biochar in the mixture of biochar and LB broth was 10wt% and the mesh size of biochar was 60 mesh), and cultured in a double-layer full-temperature shaker at 30°C for 30h (the speed was set at 80r / min) to fully fix the mixed bacteria on the biochar; after the fixation process was completed, the mixed bacteria were vacuum dried using a freeze dryer to obtain a microbial agent and stored at 4°C for standby use. The effective viable count of the obtained microbial agent was ≥1.6×10 9 CFU / g.

[0043] Preparation Example 3

[0044] Preparation of microbial inoculants:

[0045] Pseudomonas aeruginosa, Acinetobacter venetianus, Bacillus flexus, Bacillus aryabhattai, and Bacillus megaterium were cultured respectively; specifically, the bacteria to be cultured were inoculated with LB medium (LB medium including 10 g / L tryptone, 5 g / L yeast extract, 10 g / L sodium chloride, pH 7.0) at an inoculum amount of 10 wt%, and cultured in a shaker (temperature 30 ° C, speed 150 r min -1 , time is 24h); then transferred to another LB medium with an inoculum of 10wt% and cultured under the same conditions for 30h; then placed in a centrifuge tube, centrifuged at 8000r / min in a high-speed centrifuge for 30min, poured out the supernatant, added sterile saline and shook evenly, centrifuged again at 8000r / min for 30min, poured out the supernatant, added sterile saline and shook evenly for standby use;

[0046] The cultured Pseudomonas aeruginosa, Acinetobacter venetianus, Bacillus flexus, Bacillus aryabhattai, and Bacillus megaterium are mixed in a volume ratio of 3:6:1:1:1 to obtain a mixed bacteria;

[0047] The mixed bacteria were transferred to another LB medium at an inoculation rate of 10 wt %, cultured in a double-layer full-temperature shaker at 30° C. for 30 h (speed set at 80 r / min), and then concentrated to obtain a microbial agent which was stored at 4° C. for future use.

[0048] Example 1

[0049] This embodiment provides a combined remediation method for petroleum contaminated soil (UCB-2%), wherein the method comprises:

[0050] 200 g of the petroleum-contaminated soil to be treated prepared in Preparation Example 1 was taken and placed in a 500 mL beaker, and urea peroxide and sodium carbonate were added and mixed (the mass of the petroleum-contaminated soil to be treated was 100%, and the amount of urea peroxide added was 2%; the molar ratio of urea peroxide to sodium carbonate was 4:1); deionized water was added to adjust the water-soil ratio to 1:1, and to prevent soil moisture loss, the beaker was sealed with tin foil, and holes were evenly punched for exhaust, and the beaker was placed in an incubator at 25° C. for constant temperature reaction for 8 days, and the mixture was stirred every 12-24 hours and the water loss due to evaporation was replenished in time;

[0051] Potassium dihydrogen phosphate, humic acid and the microbial agent prepared in Preparation Example 2 were added to the reacted soil (based on the mass of the petroleum-contaminated soil to be treated as 100%, the amount of potassium dihydrogen phosphate added was 0.2%, the amount of humic acid added was 0.5%, and the amount of microbial agent added was 10%), and the temperature was controlled to be 25°C and the soil moisture was controlled to be 40% for cultivation in an ecological incubator, and sampling and analysis were performed at 0d, 8d, 16d, 24d, 32d, 40d, and 48d. The changes in the concentration of petroleum hydrocarbons in the soil were determined using an infrared oil meter according to the method of "Determination of Petroleum in Soil by Infrared Spectrophotometry" (HJ 1051-2019).

[0052] The results are as follows Figure 1 , Figure 2 As shown, after 48 days, the removal rate of petroleum hydrocarbons was 83.4%.

[0053] Comparative Example 1

[0054] This comparative example provides a method for remediating petroleum-contaminated soil (CK), wherein the method comprises:

[0055] Take 200g of the petroleum-contaminated soil to be treated prepared in Preparation Example 1, put it into a 500mL beaker, add deionized water, adjust the water-soil ratio to 1:1, seal the beaker with tin foil to avoid soil moisture loss, pierce holes evenly for exhaust, place it in an incubator at 25°C for 48 days, stir every 12-24h and replenish the water lost due to evaporation in time; sample and analyze at 0d, 8d, 16d, 24d, 32d, 40d, and 48d respectively. According to the method of "Infrared Spectrophotometry for Determination of Petroleum in Soil" (HJ1051-2019), the change of soil petroleum hydrocarbon concentration was determined using an infrared oil meter.

[0056] The results are as follows Figure 1 , Figure 2 As shown, after 48 days, the removal rate of petroleum hydrocarbons was 8.2%.

[0057] Comparative Example 2

[0058] This comparative example provides a method for remediating petroleum-contaminated soil (UF-2%), wherein the method comprises:

[0059] Take 200g of the petroleum-contaminated soil to be treated prepared in Preparation Example 1, put it into a 500mL beaker, add urea peroxide, citric acid, and ferrous sulfate heptahydrate (based on the mass of the petroleum-contaminated soil to be treated as 100%, the amount of urea peroxide added is 2%; urea peroxide and Fe 2+ The molar ratio of citric acid to Fe is 30:1. 2+ The molar ratio of soil to water was 1:1); deionized water was added to adjust the water-soil ratio to 3:2. To avoid soil moisture loss, the beaker was sealed with tin foil, and holes were evenly punched for exhaust. It was placed in an incubator at 25°C for 8 days. Stirring was performed every 12-24 hours and the water loss due to evaporation was replenished in time. Samples were taken after 8 days, and the changes in soil petroleum hydrocarbon concentration were determined using an infrared oil meter according to the method of "Determination of Petroleum in Soil by Infrared Spectrophotometry" (HJ 1051-2019).

[0060] The results are as follows Figure 2 As shown, after 8 days, the removal rate of petroleum hydrocarbons was 36.1%.

[0061] Comparative Example 3

[0062] This comparative example provides a method for remediating petroleum-contaminated soil (UC-2%), wherein the method comprises:

[0063] Take 200g of the petroleum-contaminated soil to be treated prepared in Preparation Example 1, put it into a 500mL beaker, add urea peroxide and sodium carbonate and mix well (the mass of the petroleum-contaminated soil to be treated is 100%, the amount of urea peroxide added is 2%; the molar ratio of urea peroxide to sodium carbonate is 4:1); add deionized water, adjust the water-soil ratio to 1:1, and seal the beaker with tin foil to avoid soil moisture loss, pierce holes evenly for exhaust, and place it in an incubator at 25°C for 8 days, stir every 12-24h and replenish the water lost due to evaporation in time. Take samples after 8 days, and use an infrared oil meter to measure the change in soil petroleum hydrocarbon concentration according to the method of "Infrared Spectrophotometry for Determination of Petroleum in Soil" (HJ1051-2019).

[0064] The results are as follows Figure 2 As shown, after 8 days, the removal rate of petroleum hydrocarbons was 44.1%.

[0065] Comparative Example 4

[0066] This comparative example provides a method for remediating petroleum-contaminated soil (UC-4%), wherein the method comprises:

[0067] Take 200g of the petroleum-contaminated soil to be treated prepared in Preparation Example 1, put it into a 500mL beaker, add urea peroxide and sodium carbonate and mix well (the mass of the petroleum-contaminated soil to be treated is 100%, the amount of urea peroxide added is 4%; the molar ratio of urea peroxide to sodium carbonate is 4:1); add deionized water, adjust the water-soil ratio to 1:1, and seal the beaker with tin foil to avoid soil moisture loss, pierce holes evenly for exhaust, and place it in an incubator at 25°C for 8 days, stir every 12-24h and replenish the water lost due to evaporation in time. Take samples after 8 days, and use an infrared oil meter to measure the change in soil petroleum hydrocarbon concentration according to the method of "Infrared Spectrophotometry for Determination of Petroleum in Soil" (HJ1051-2019).

[0068] The results are as follows Figure 2 As shown, after 8 days, the removal rate of petroleum hydrocarbons was 62.7%.

[0069] Comparative Example 5

[0070] This comparative example provides a method for remediating petroleum-contaminated soil (B), wherein the method comprises:

[0071] Take 200g of the petroleum-contaminated soil to be treated prepared in Preparation Example 1, put it into a 500mL beaker, add potassium dihydrogen phosphate, humic acid and the microbial agent prepared in Preparation Example 2 (based on the mass of the petroleum-contaminated soil to be treated as 100%, the amount of potassium dihydrogen phosphate added is 0.2%, the amount of humic acid added is 0.5%, and the amount of microbial agent added is 10%), control the temperature to 25°C, control the soil moisture to 40% and culture it in an ecological incubator, and sample and analyze it at 0d, 8d, 16d, 24d, 32d, 40d, and 48d. According to the method of "Infrared Spectrophotometry for the Determination of Petroleum in Soil" (HJ 1051-2019), the change of soil petroleum hydrocarbon concentration was determined using an infrared oil meter.

[0072] The results are as follows Figure 1 , Figure 2 As shown, after 48 days, the petroleum hydrocarbon removal rate was 36.1%.

[0073] Comparative Example 6

[0074] This comparative example provides a method for remediating petroleum-contaminated soil (UFB-2%), wherein the method comprises:

[0075] Take 200g of the petroleum-contaminated soil to be treated prepared in Preparation Example 1, put it into a 500mL beaker, add urea peroxide, citric acid, and ferrous sulfate heptahydrate (based on the mass of the petroleum-contaminated soil to be treated as 100%, the amount of urea peroxide added is 2%; urea peroxide and Fe 2+ The molar ratio of citric acid to Fe is 30:1. 2+ The molar ratio is 1:1); deionized water is added to adjust the water-soil ratio to 3:2. To prevent soil moisture loss, the beaker is sealed with tin foil, holes are evenly punched for exhaust, and the beaker is placed in an incubator at 25°C for 8 days. Stir every 12-24 hours and replenish the water lost due to evaporation in time;

[0076] Potassium dihydrogen phosphate, humic acid and the microbial agent prepared in Preparation Example 2 were added to the reacted soil (based on the mass of the petroleum-contaminated soil to be treated as 100%, the amount of potassium dihydrogen phosphate added was 0.2%, the amount of humic acid added was 0.5%, and the amount of microbial agent added was 10%), and the soil was placed in an ecological incubator at 25°C and 40% humidity for culture, and samples were taken and analyzed at 0d, 8d, 16d, 24d, 32d, 40d, and 48d. The changes in the concentration of petroleum hydrocarbons in the soil were determined using an infrared oil meter according to the method of "Infrared Spectrophotometry for the Determination of Petroleum in Soil" (HJ1051-2019).

[0077] Comparative Example 7

[0078] This comparative example provides a combined remediation method for petroleum contaminated soil (UCLB-2%), wherein the method comprises:

[0079] 200 g of the petroleum-contaminated soil to be treated prepared in Preparation Example 1 was taken and placed in a 500 mL beaker, and urea peroxide and sodium carbonate were added and mixed (the mass of the petroleum-contaminated soil to be treated was 100%, and the amount of urea peroxide added was 2%; the molar ratio of urea peroxide to sodium carbonate was 4:1); deionized water was added to adjust the water-soil ratio to 1:1, and to prevent soil moisture loss, the beaker was sealed with tin foil, and holes were evenly punched for exhaust, and the beaker was placed in an incubator at 25° C. for constant temperature reaction for 8 days, and the mixture was stirred every 12-24 hours and the water loss due to evaporation was replenished in time;

[0080] Potassium dihydrogen phosphate, humic acid and the microbial agent prepared in Preparation Example 3 were added to the reacted soil (based on the mass of the petroleum-contaminated soil to be treated as 100%, the amount of potassium dihydrogen phosphate added was 0.2%, the amount of humic acid added was 0.5%, and the amount of microbial agent added was 10%), and the temperature was controlled to be 25°C and the soil moisture was controlled to be 40% for cultivation in an ecological incubator, and sampling and analysis were performed at 0d, 8d, 16d, 24d, 32d, 40d, and 48d. The changes in the concentration of petroleum hydrocarbons in the soil were determined using an infrared oil meter according to the method of "Infrared Spectrophotometry for the Determination of Petroleum in Soil" (HJ 1051-2019).

[0081] The results are as follows Figure 1 , Figure 2 As shown, after 48 days, the removal rate of petroleum hydrocarbons was 72.1%.

[0082] By comparing Example 1 and Comparative Example 7, it can be seen that the biochar-loaded bacterial agent (petroleum hydrocarbon removal rate 83.4%) increases the petroleum hydrocarbon removal rate by 15% compared with the free bacterial solution (petroleum hydrocarbon removal rate 70.7%).

[0083] It can be seen from the petroleum hydrocarbon removal rate data of Example 1 and Comparative Examples 1 to 5 that the use of CO3 2- The combined restoration of activated urea peroxide and bioreinforcement is higher than the restoration using only a single microorganism (such as comparative example 5) and higher than the restoration using only CO3 2- Activate carbamide peroxide chemical repair (such as comparative example 3), higher than 2 times the amount of carbamide peroxide CO3 2- Activate carbamide peroxide chemical repair (such as comparative example 4). And adopt the CO3 2- The removal efficiency of petroleum hydrocarbons by activated urea peroxide combined with bioremediation is higher than that of single microbial remediation and CO3 remediation alone. 2- The removal rate of petroleum hydrocarbons by activated carbamide peroxide chemical remediation and CO3 2- The activated urea peroxide oxidative repair and the composite microbial bacteria repair are effectively coordinated to achieve the effect of 1+1>2.

[0084] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A combined remediation method for petroleum-contaminated soil, wherein: The method includes: The urea peroxide, activator and the petroleum contaminated soil to be treated are mixed and reacted at room temperature under the condition of a water-soil ratio of 1:1-1:4; wherein the activator is a 2- wherein, based on the mass of the petroleum-contaminated soil to be treated as 100%, the amount of urea peroxide added is 1%-3%; urea peroxide and CO3 provided by the activator 2- The molar ratio is 1:1-5:1; Add a microbial agent to the reacted soil and perform microbial remediation under the condition of soil moisture of 20%-50%; wherein the microbial agent is a biochar-loaded mixed bacterial agent, the mixed bacteria include Pseudomonas aeruginosa, Acinetobacter venezuelae, Bacillus flexus, Bacillus aryabordoi and Bacillus megaterium, the particle size of the biochar is 30-80 mesh; the effective viable bacteria count of the biochar-loaded mixed bacterial agent is ≥1.6×10 9 CFU / g; based on the mass of the petroleum-contaminated soil to be treated as 100%, the amount of microbial agent added is 1%-5%.

2. The method according to claim 1, wherein: Sodium carbonate is used as the activator.

3. The method according to claim 1, wherein: The volume ratio of Pseudomonas aeruginosa, Acinetobacter venezuelae, Bacillus curvatus, Bacillus ayedoensis, and Bacillus megaterium is 3-6:4-7:1-3:1-3:

1.

4. The method according to claim 1 or 3, wherein: The microbial agent is prepared by the following method: Pseudomonas aeruginosa, Acinetobacter venezuelae, Bacillus curvatus, Bacillus aryabordoi, and Bacillus megaterium are mixed to obtain a mixed bacteria; The mixed bacteria are transferred to a mixture of biochar and culture medium for cultivation, so that the mixed bacteria are fixed on the biochar; After the fixing process is completed, the microbial agent is obtained through drying.

5. The method according to claim 1, wherein: The microbial agent is added to the reacted soil and a nutrient source is added at the same time; the nutrient source includes a potassium source and humic acid.

6. The method according to claim 5, wherein: The potassium source is potassium dihydrogen phosphate.

7. The method according to claim 6, wherein: Based on the mass of the petroleum-contaminated soil to be treated as 100%, the added amount of potassium dihydrogen phosphate is 0.1%-0.2%, and the added amount of humic acid is 0.1%-0.5%.

8. The method according to claim 1, wherein: The petroleum contaminated soil to be treated is prepared by the following method: The petroleum contaminated soil is crushed and sieved to obtain the petroleum contaminated soil to be treated; wherein the sieving is through a 10-20 mesh sieve.

9. The method according to any one of claims 1 to 3, wherein: The petroleum hydrocarbon content in the petroleum-contaminated soil to be treated does not exceed 50,000 mg / kg.

10. The method according to claim 1, in, The reaction time is 1-4 days; Among them, the time for microbial remediation is 30-50 days.

Images