| In the process of oil exploration, mining, transport and processing, amount of petroleum flowed into the environment due to careless handling or incidental considerable, which has become the world’s environmental problems. The soil petroleum pollution is one of the environmental pollution. In the oil-producing regions of northern China, Area of oil pollution has expanded each year, oil pollution problem has become increasingly prominent and serious, how to fix oil-contaminated soil has become the focus. Phytoremediation method has the advantages of low processing costs, no secondary pollution and green, which has become the research focus of domestic and international environmental governance. In this paper, we carried out the determination of total petroleum hydrocarbons and bioremediation technology studies to petroleum-contaminated soil, which provides some technical reference for the bioremediation of petroleum contaminated soil.The main results of this study are as follows:In this paper, established a gas chromatography-mass spectrometry segmented detection method of total petroleum hydrocarbons in the soil, which is used to detect microbial enhanced phytoremediation oil content of petroleum contaminated soil and evaluation repairing effect. Identified pre-treatment of petroleum contaminated soil: Soxhlet extraction organic extraction method extract petroleum hydrocarbons in the soil, and then separated by column chromatography petroleum hydrocarbons. Identified different fractions alternative compounds, and then established instrumental quality control methods through alternative compounds, the results can meet the qualitative and quantitative requirements analysis and can be used to detect oil the content of petroleum hydrocarbons in contaminated soil. Petroleum contaminated soil instrumental quantitative analysis methods:gas chromatography-mass spectrometry (GC/MS) ion scan mode (SCAN), section integral calculate the amount of different fractions of petroleum compounds. The present method is not only capable of measuring all the structures of the C8-C34hydrocarbons, but also to calculate the exact content of the compound of the different fractions, which accurately reflect the degree of contamination of the soil and toxicity.The improved root exudates cycle collection device accurately collect and study the root exudates. Identified by GC-MS detection to the5main substances in the root exudates of tall fescue are phenol, benzoic acid, p-hydroxybenzoic acid, palmitic acid, stearic acid. I selected4kinds of organic acid to research D5A strains allelopathy. These four substances chemotactic effect of bacteria Klebsiella D5A results show that D5A strain the chemotaxis index greater than2under concentrations of organic acids10to40μm, the chemotactic effect is remarkable, the D5A bacteria have a positive dependent chemotaxis to these four organic acids, the maximal chemotactic effect was obtained from Palmitic acid. In addition, D5A bacteria chemotaxis index max when the organic acid is30μM. The study above four acid flora mobility results show that: it is no obvious induction effect on the microflora to the hydroxy benzoic acid and stearic acid, produce the inducing effect of benzoic acid and palmitic acid is significant on flora migration, benzoic acid and palmitic acid corresponding bacteria circle diameter is1.58and1.98times respectively compared with comparison.This paper studies the laboratory screening plant growth promoting bacteria adaptability of salinity and pH adversity. The results show:the D5A strain in the pH range of4to10and four in the medium can grow normally, which further verified with strong alkali patience, the pH of the medium after growth of strain is about7; D5A growth gradually suppressed with increasing the salt content, the OD of D5A broth is about1.2and can produce a certain amount of IAA in9%salt concentration, which showed strong salt tolerance. Designed test tube agar test under laboratory conditions, the results showed that:in the tall fescue’s total length, root surface area, root tip numberand root average diameter, compared with the control, D5A bacteria inoculation treatment increased104.6%,29.1%,146.9%and reduced40.7%. S-B bacteria inoculated treatment increased80.1%,0.5%,73.1%and reduced40.0%. Trains D5A and S-B promoted the development of tall fescue root in varying degrees, which has a significant role in promoting tall fescue growth under salt stress, the effect of D5A promoting is more significant.Over a pot experiment, this paper explored phytoremediation and microbial enhanced phytoremediation in the soil purification role in the study of tall fescue for oil contaminated soil remediation effect. The pot experiment results show that:the total petroleum hydrocarbon reduced66.4%after tall fescue+D5A treated, while the control is only51.2%. The inoculated plant biomass, chlorophyll content, root activity and petroleum hydrocarbons degradation in the soil higher than the non-inoculated plants. Tall fescue strains can effectively promote plant growth in the oil-contaminated soil, rhizosphere promoting bacteria D5A is more pronounced on growth promoting effect. |
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