【作者】 肖洲强；

【导师】 黄廷林；

【作者基本信息】 西安建筑科技大学 ， 市政工程， 2007， 硕士

【摘要】 目前国内利用微生物修复石油污染土壤的研究已有不少成果，但这些研究基本上都集中在改善微生物的生态条件，并且大多数研究仅限于实验室，因此课题组开展了利用微电场和膨松剂等强化微生物修复的组合技术的研究，并且首次针对陕北石油污染土壤进行了现场中试试验，探讨了微生物的修复条件，初步确定微生物修复陕北石油污染土壤的适宜技术参数。实验结果表明：对实验室分离的高效菌在实验室条件下翻耕次数越多，其降解率越高，翻耕频率最高的降解率为92.6％，比不翻耕的降解率60.25％高出32.35％。在添加膨松剂的条件下，由于添加蓬松剂提高了土壤的通透性，为微生物降解石油烃提供了足够氧从而提高了微生物的降解率，添加锯末土样的降解率为87.96％，其次为稻壳，降解率达到71.19％，最后为麦皮，降解率为38.98％。不加膨松剂的降解率仅为35.05％，添加膨松剂土样的降解率均比不加膨松剂的降解率高。在匀强电场强化微生物修复实验结果显示，最适宜微生物降解石油烃的电场条件为300V.m^-1，辐照时间为10min，石油降解率比不辐照土样的降解率高出12％，并且电场辐照时间不宜过长，气质联机质谱分析显示，陕北石油污染物去除的主要组分为饱和烃，经过54d的降解已基本被去除。饱和烃被去除的烷烃主要是C₁₂H₄₄，C₂₀H₄₂，C₁₈H₃₈和C₁₉H₄₀。由此可见，微生物+膨松剂+微电场修复陕北石油污染土壤是可行的。现场修复实验表明，适当的营养配比对微生物降解石油烃是一个关键因素，添加营养的土样的降解率为73％比不加营养的降解率65.3％高出近9个百分点，实验结果同时表明由于陕北常年干旱缺水，过多的翻耕不利于水分的保持，故翻耕周期应进一步增长。其中加菌翻耕的降解率为65.26％，加菌不翻耕的降解率为72.42％,加菌不翻耕土样的降解率比加菌翻耕土样的降解率高7.12个百分点。在现场上、中、下层土样实验结果表明，下层的降解率为83.3％，中层的降解率为67.33％，上层的降解率为66.81％，下层土样的降解率比上层土样的降解率高出16.22个百分点。这进一步证明了水分在微生物降解石油污染中的关键作用。更多还原

【Abstract】 Many studies on bioremediation of oil-contaminated soil were reported at current time, and these mainly centered on the improvement of ecological environment of bacteria. The most important point was that most of the studies were conducted in the laboratory. Therefore, we adopted combined technologies that use weak electric field and bulking sgents to biodegradate oil-contaminated soils. Pilot-plant test was carried out to study the degradation of oil-contaminated soils. Based on the above studies, the optimal ecological conditions of oil-degrading bacteria in arid area of North Shann’xi were determined and lastly, optimal conditions for biodegrading the oil in the contaminated soils in North Shann’xi were obtained.The experiment results showed that, more farmed times can promote the degradation of the oil and the highest degradation rate is 92.6%, which is 32.35% higher than that of non-farmed soils. When bulking agents were added into the samples, different degradation rates were reached, because this can improve the ventilation of the soil, which provides sufficient oxygen for the microorganisms to get a better degradation rate of the oil-contaminated soil. And sawdust gave the best degradation rate of 87.96%, rice bran followed with 71.19%, and wheat straw ranked the last in 38.98%, all of which were better than that of no bulking agents-added samples(35.05%). 10min of radiation time and 300 V·m-1 of electric strength can be considered as the optimum conditions of the UE field to biodegrade the oil-contaminated soil and the removal rate was 12 percent higher than that of no radiation samples. By means of the GC-MS analysis, saturated hydrocarbons (C10-C40) contained in the oil-contaminated soil were almost completely degraded after 54 days of biodegradation. Therefore, bioremediation of oil-contaminated soils under the existence of the electric field and bulking agents was valid. The situ bioremediation results showed appropriate nutrients ratio was a key factor in degradation of the oil-contaminated soil, and nutrients-existing sample with degradation rate 73% was nearly 9 percent higher than that of no nutrients-added samples. Other results were also obtained, and more farmed times of samples were adverse to the degradation because of the arid area of north shann’xi. More farmed times are adverse to maintain of moisture in the soil. Therefore, the farmed period for the sample should be extended. Under the existence of sufficient moisture, anaerobic bacteria played a better role in the biodegradation of oil-contaminated soils, especially under the high pollution concentrations. The results showed that the best degradation rate was obtained when predominant bacteria are added and the soils are not farmed, and the degradation rate was 7.12 percent higher than that of bateria-added and farmed soils. The above results showed that anaerobic bacteria played a better role in biodegradation of oil-contaminated soil under high pollution concentrations. Still, this paper got 83.3%, 67.33%and 66.81% that were representing the degradation rate of the bottom, middle and upper oil-contaminated soils, respectively. And degradation rate of the bottom soil sample was 16.22 percent higher than that of the upper one. This further showed that moisture played a key role in the biodegradation of oil-contaminated soil.更多还原