Research On The Remediation Technology Of Crude Oil-contaminated Soil In Xinjiang

The main pollution of the main oil-producing areas in Xinjiang is the petroleum contaminated soil. Itssignificant is that fragile ecological environment can remediate the petroleum contaminated soil in aridareas. In order to provide technical support and theoretical basis for the remediation technology ofpetroleum contaminated soil. Based on current situation of petroleum contaminated soil in arid areas andthe major problems in remediation technology of petroleum contaminated soil. First, we imitated thenatural degradation process of petroleum contaminated soil, which controlled the concentrations ofartificial disposition from low to high (0g/kg～80g/kg). According to the orthogonal experimental design,we imitated the different soil condition by means of controlled the C:N conditions and the moisture content.We can realize the natural degradation process of petroleum contaminated soil by monitoring the change ofsoil respiration, soil dehydrogenase, catalase and polyphenal oxidase. Second, in order to studyphytoremediation effect of petroleum contaminated soil in Xinjiang. Using the low to the mediumconcentrations (<20g/kg) contaminated soil of artificial disposition. Three plants which are zea mays,Suaeda salsa L and Bermuda grass are selected as the plant of phytoremediation. Biomass and totalpetroleum hydrocarbons degradation rate are used as the detection indications. Indoor analog controlexperiment is utilized to research the remediation effect of the three plants in different concentrations ofpetroleum contaminated soil. Finally, using the microwave repair and restoration of hydrogen peroxide in10g/kg,20g/kg the two concentrations of petroleum contaminated soil. The advantage of microwaveheating technology was taken to remediate the crude oil contaminated soil rapidly. With simulationexperiments, used gray desert soil, and connected the biological black carbon with microwave technology.Based on the single-factor test, used the Box-Behnken experimental design and response surfacemethodology, used the biological black carbon as the exogenous absorbing medium. The effect ofmicrowave irradiation time, soil moisture content and biological black carbon content in microwavethermal remediation of soil contaminated with petroleum was discussed. In the hydrogen peroxide repairprocess, controlled the two factors about hydrogen peroxide dosage and soil moisture with three levels. Studied the hydrogen peroxide repaired effects of different concentration of oil pollutions. The main resultsobtained are as follows:1. Simulation study of natural degradation of petroleum contaminated soil in Xinjiang. The pH value isalkaline in crude oil-contaminated soil. During the experiment as a whole cycle, there was a downwardtrend of the pH value. Oil pollution concentrations have a significant impact on Dehydrogenase activityin soils. The C: N value had possible interactions between soil moisture. oil concentrations had a greaterimpact on Catalase activity in low C: N-value cases. Polyphenol oxidase had a greater activity in the largerC: N value of6:1. Results showed that the soil respiration was inhibited when the crude oil concentrationis less than15g/kg in the first six days. With the concentration of crude oil increasing, the effect change toexcitation from inhibition. After14days, all the soil respiration rates reached their equilibrium, but thecontaminated soils have a higher soil respiration rate than the control treatment. Soil moisture content haveno significant effect on soil respiration (pP>0.05), while the C: N ratio have significant effect (pP<0.05),which increased the soil respiration rate. Results of the residues of total petroleum hydrocarbons in soilsafter60days monitoring indicated that the oil degradation have the same factor as the soil respiration. Thecrude oil changed the factors of soil respiration. The effect of C: N ratio was greatest while the soilmoisture content was lowest.2. Research of phytoremediation effect of three plants to petroleum contaminated soil in Xinjiang. Theresults showed that different plants have different response to crude oil. The low-concentration crude oilcontamination（<5g/kg）can stimulate the growth of Zea mays, a significant increase in above-groundbiomass (P<0.05).; Bermuda grass has a high tolerance and adaptability in moderate-high (5g/kg-20g/kg)petroleum contaminated soil. The condition of moderate concentrations and low salt concentration canpromote the above-ground biomass of Suaeda salsa L (P<0.01).; Viewing from total petroleumhydrocarbons degradation rate, Bermuda grass has the highest rate in low-moderate (<10g/kg) petroleumcontaminated soil. We should choose the different plants for different concentrations ofpetroleum-contaminated soil.3. Research of Microwave Thermal Remediation of Soil Contaminated with Crude Oil in Xinjiang. Theresults revealed that, under the condition of800W microwave power,10min microwave irradiation time,10.30%soil moisture content,6.90%biological black carbon content was the best condition, then morethan95.76%oil was removed. In addition, the experiment results showed that there was a significance interaction in soil moisture content and biological black carbon content.4. Research of hydrogen peroxide Remediation of Soil Contaminated with Crude Oil in Xinjiang. In10g/kg petroleum contaminated soil, the highest rates of petroleum hydrocarbon degradation appeared in soilmoisture content of50%and hydrogen peroxide dosage of0.6ml/g. In20g/kg petroleum contaminatedsoil, the highest rates of petroleum hydrocarbon degradation appeared in soil moisture content of50%andhydrogen peroxide dosage of0.4ml/g.