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CN-122007143-A - Microbial remediation method for petroleum hydrocarbon pollutants difficult to degrade in soil

CN122007143ACN 122007143 ACN122007143 ACN 122007143ACN-122007143-A

Abstract

The invention relates to the technical field of soil remediation methods, in particular to a microbial remediation method for nondegradable petroleum hydrocarbon pollutants in soil, which comprises the steps of ploughing the soil polluted by the nondegradable petroleum hydrocarbon pollutants, adding biochar, burying an aeration well and an extraction well, burying a cathode and an anode, and carrying out electrochemical treatment at constant potential; and in the biological restoration stage, direct-current voltage is applied in an intermittent mode to carry out electrochemical assistance, and periodic sampling is carried out to monitor and analyze the components in the soil, so that the restoration process is completed after the restoration end point is reached. The invention provides a proper growth, metabolism and field planting environment for the compound microbial agent by adopting the steps, and simultaneously, the electrochemical treatment parameters are accurately regulated and controlled, so that the high-efficiency and thorough degradation of the petroleum hydrocarbon pollutants difficult to degrade is realized.

Inventors

  • GUO YUECHUAN
  • YANG BO
  • HU HAIJIE
  • LI JINLING
  • QU CHENGDUN

Assignees

  • 西安石油大学

Dates

Publication Date
20260512
Application Date
20260410

Claims (10)

  1. 1. A microbial remediation method for petroleum hydrocarbon pollutants difficult to degrade in soil is characterized by comprising the following steps: S1, ploughing soil polluted by petroleum hydrocarbon pollutants difficult to degrade, adding biochar, burying an aeration well and an air extraction well in the polluted soil, and regulating the pH value in the soil to 6-8; S2, inserting a quincuncial arranged cathode and anode which are staggered with an aeration well into the soil, performing electrochemical treatment at constant potential, controlling the potential to be 2.0-3.5V, and performing primary electrochemical activation on the petroleum hydrocarbon pollutants difficult to degrade for 12-24 hours; s3, applying a nutrient salt slow release fertilizer, a growth matrix, modified straw and a biosurfactant to soil, and then uniformly applying a compound microbial agent; s4, water is sprayed into the soil regularly, ventilation is carried out through an aeration well and an air extraction well regularly, and in a bioremediation stage, direct-current voltage of 1.0-2.5V is applied in an intermittent mode for electrochemical assistance, and each time lasts for 2-6 hours; s5, periodically sampling to monitor and analyze the components in the soil, and supplementing nutrient salt slow-release fertilizer, biosurfactant or compound microbial agent according to the monitoring and analyzing result, and completing the repairing process after reaching the repairing end point.
  2. 2. The method for repairing microorganisms in soil difficult to degrade petroleum hydrocarbon pollutants according to claim 1, wherein in S1, the aeration wells and the gas extraction wells are arranged in a quincuncial staggered manner, and the distance between the aeration wells and the gas extraction wells is 3-5m.
  3. 3. A method for repairing microorganisms difficult to degrade petroleum hydrocarbon pollutants in soil according to claim 1, wherein in S2, the anode is an inert electrode, the cathode is a stainless steel electrode or a graphite electrode, the distance between the cathode and the anode is 2-3m, the bottoms of the cathode and the anode are inserted into the soil for 40-60cm, and the tops of the cathode and the anode are 10-15cm higher than the surface of the soil.
  4. 4. The method for repairing microorganisms in soil difficult to degrade petroleum hydrocarbon pollutants according to claim 1, wherein in S2, when the soil conductivity is lower than 1mS/cm, 0.1-0.5mol/L sodium sulfate solution is sprayed into the soil.
  5. 5. The microbial remediation method of the petroleum hydrocarbon pollutants difficult to degrade in soil according to claim 1, wherein in S3, the nutrient salt slow-release fertilizer is prepared by mixing coated urea, slow-release potassium dihydrogen phosphate and potassium chloride according to the effective components of N: P: K in a mass ratio of (8-12) to 1.
  6. 6. The method for repairing microorganisms of refractory petroleum hydrocarbon contaminants in soil according to claim 1, wherein in S3, the growth substrate comprises one or more of glucose, sucrose, sodium citrate or straw leachate.
  7. 7. The method for repairing microorganisms difficult to degrade petroleum hydrocarbon pollutants in soil according to claim 1, wherein in S3, the compound microbial inoculum comprises at least two of bacillus, pseudomonas, rhodococcus, nocardia and microbacteria.
  8. 8. The method for repairing microorganisms of refractory petroleum hydrocarbon contaminants in soil according to claim 1, wherein in S3, the biosurfactant is one or more of rhamnolipids and sophorolipids.
  9. 9. The method for repairing microorganisms in soil difficult to degrade due to petroleum hydrocarbon pollutants according to claim 1, wherein in S4, the electrochemical auxiliary current density is 5-10mA/cm 2 , and the intermittent treatment is 2-3 times per day.
  10. 10. The method for repairing microorganisms in soil difficult to degrade petroleum hydrocarbon pollutants according to claim 1, wherein in S5, the repairing end point is that the total concentration of the difficult to degrade petroleum hydrocarbon pollutants in the soil is lower than a target risk management standard value, and the soil activity is recovered to more than 80% of the uncontaminated soil.

Description

Microbial remediation method for petroleum hydrocarbon pollutants difficult to degrade in soil Technical Field The invention relates to the technical field of soil remediation methods, in particular to a microbial remediation method for petroleum hydrocarbon pollutants difficult to degrade in soil. Background With the continuous expansion of petroleum exploitation, transportation, processing and application scale, the problems of petroleum leakage, oil pollution on the ground and the like are increasingly prominent, and a large amount of petroleum hydrocarbon pollutants (such as polycyclic aromatic hydrocarbon, long-chain alkane, aromatic hydrocarbon derivatives and the like) which are difficult to degrade enter the soil environment. The pollutants have the characteristics of strong durability, high hydrophobicity, high biotoxicity and difficult natural degradation, are easy to be adsorbed on the surfaces of soil particles, accumulate in soil for a long time, not only can damage the soil aggregate structure and reduce the soil fertility and inhibit the activity of soil microbial communities, but also can be transmitted through food chain enrichment, thereby threatening the growth of animals and plants and the health of human beings. At present, the repair technology of the petroleum hydrocarbon pollutants difficult to degrade in soil mainly comprises three major categories of physical repair, chemical repair and microbial repair. The physical repair (such as soil leaching and thermal desorption) has the defects of high cost, high energy consumption, easiness in causing the damage of a soil structure and secondary pollution, and the chemical repair (such as oxidation of an oxidant) can quickly degrade part of pollutants, but the use of a chemical reagent is easy to destroy the microecological balance of the soil, has limited degradation effect on refractory components such as high-ring polycyclic aromatic hydrocarbon and the like, and is easy to generate toxic intermediate products. The microbial remediation is a mainstream technology for remedying petroleum hydrocarbon pollution of the current soil due to the advantages of environmental protection, low cost, simple operation, in-situ remediation, complete mineralization of pollutants into harmless substances and the like. However, the single microorganism repair still has obvious short plates, namely the chemical structure of the petroleum hydrocarbon pollutants which are difficult to degrade is stable, and the microorganism has low degradation efficiency and long period. The soil has deficient nutrient substances and poor ventilation condition, and is easy to cause inhibition of the activity of degrading bacteria and difficult field planting. The conductivity of partial polluted soil is low, the contact probability of microorganisms and pollutants is limited, and the repairing effect is further restricted. Therefore, the research and development of the microbial remediation method for the petroleum hydrocarbon pollutants difficult to degrade in soil has important practical significance and application value. Disclosure of Invention The invention aims to provide a microbial remediation method for petroleum hydrocarbon pollutants difficult to degrade in soil, which provides a proper growth, metabolism and field planting environment for a compound microbial agent, and simultaneously, accurately regulates and controls electrochemical treatment parameters, avoids damage of a high-strength electric field to microbial activity, avoids repairing short plates with low degradation efficiency and long period by a single microorganism, and realizes efficient and thorough degradation of the petroleum hydrocarbon pollutants difficult to degrade. In order to achieve the above purpose, the invention provides a microorganism repairing method for petroleum hydrocarbon pollutants difficult to degrade in soil, which comprises the following steps: S1, ploughing soil polluted by petroleum hydrocarbon pollutants difficult to degrade, adding biochar, burying an aeration well and an air extraction well in the polluted soil, and regulating the pH value in the soil to 6-8; S2, inserting a quincuncial arranged cathode and anode which are staggered with an aeration well into the soil, performing electrochemical treatment at constant potential, controlling the potential to be 2.0-3.5V, and performing primary electrochemical activation on the petroleum hydrocarbon pollutants difficult to degrade for 12-24 hours; s3, applying a nutrient salt slow release fertilizer, a growth matrix, modified straw and a biosurfactant to soil, and then uniformly applying a compound microbial agent; s4, water is sprayed into the soil regularly, ventilation is carried out through an aeration well and an air extraction well regularly, and in a bioremediation stage, direct-current voltage of 1.0-2.5V is applied in an intermittent mode for electrochemical assistance, and each time lasts for 2-6 hours; s5, peri