Microbial Remediation Of Petroleum Pollution In Deep Soil

With the rapid development of China's economy,the demand for energy is increasing year by year;the mileage of crude oil and refined oil gathering and transportation pipelines is increasing.Oil pipelines and storage tanks can leak for various reasons,contaminating deep soil and contaminating groundwater.There are many remediation methods for deep oil-contaminated soil,including in-situ remediation and ectopic remediation,among which in-situ microbial remediation is the most economical and easy to operate method.This method can effectively repair oil pollution under the premise of ensuring minimum harm to soil ecology.This paper takes microbial remediation of oil pollution of deep soil as the research object to find efficiently method of microbial remediation,and uses an indoor simulation device to explore the effect of in-situ microbial remediation on the remediation of deep soil oil pollution.The research results are as follows.By screening petroleum-degrading bacteria?Pseudomonas aeruginosa D-5,Achromobacter C-2,and Acinetobacter A-3?,which were mixed in a ratio of 5:1:5?mixed bacteria?.At a Tween80 concentration of 150 mg/L,mixed bacteria with a mass fraction of 6%was added into the petroleum medium.After 7 days of treatment,the oil content decreased from 2000 mg/L to 257.6 mg/L,and the degradation rate reached 87.12%.It shows that the mixed bacteria have a good degradation effect on crude oil and can be used as a remediation bacterium for oil-contaminated soil.The bioaugmentation?adding bacterial agents?was used to repair oil-contaminated soil,and the use of biostimulation?nutrient solution?to improve the efficiency of repair.When the adding amount of bacterial solution in soil is 6%,after 53 days of restoration,the M4?bacterial agent?soil petroleum degradation rate reaches?64±3.4?%,and M5?bacterial agent+nutrient solution?reaches?76.9±2.2?%.It shows that the method of the M5 experimental group can effectively repair the petroleum hydrocarbon,and provide a feasible method for the repair of deep soil.Based on the remediation method of the M5 group,the biodegradability of the oil contaminated soil at a depth of 2m was analyzed using a deep soil pollution simulation and remediation device.After 70 days of restoration,under the natural degradation?NA?,degradation rate of oil petroleum in the soil at 0¹cm from the center of the restoration is?16.3±0.7?%,which is close to the degradation rate?12.2±0.3?%at 4⁵cm;under biostimulation?BS?,The degradation rate at 0¹cm reaches?37.7±1.5?%,and the degradation rate at 4⁵ cm reaches?29.9±0.6?%;under bioaugmentation?BA?,the degradation rate at 0¹cm reaches?52.5±1?%,the degradation rate at 4⁵ cm reached?20.1±0.5?%,indicating that in situ microbial remediation of deep soil will decrease significantly with the remediation center,mainly related to the degree of soil clearance;under bioaugmentation-biostimulation?BA-BS?,the degradation rate at 0¹cm reached?80.5±0.9?%,and the degradation rate at 4⁵cm reached?52.6±1.1?%;at 0¹cm,the number of bacteria at the BA-BS group reached 10^9.3CFU/g soil,BS group reached 10^6.3CFU/g soil and the NA group reached 10^5.3CFU/g soil.Overall,it can be seen that bioaugmentation-biostimulation?BA-BS?can effectively increase the concentration of soil bacteria and efficiently repair oil pollution in deep soil.