【作者】 张静；

【导师】 王加宁； 高永超；

【作者基本信息】 山东师范大学 ， 工程硕士（专业学位）， 2016， 硕士

【摘要】 石油污染一直以来都是影响油田地区土壤环境安全的重要问题,也是国内外研究的热点问题。我国油田地区土壤除了油污染以外,还面临着盐碱化严重的问题,油盐双重污染大大增加了处理难度,也使得传统的微生物修复工艺遭遇瓶颈。电动—微生物技术是近几年发展起来的一门新兴修复技术,已在常规石油污染土壤修复工作中取得较好效果。为研究该技术治理石油污染盐碱土壤的可行性,遂开展了本课题的研究工作。本文以山东东营孤岛黄河三角洲地区未受石油污染的盐碱土壤作为研究对象,通过人工掺油的方式,配成2%石油浓度,来模拟实际油盐污染土壤。研究工作主要分为三大部分:首先,研究电动技术对石油污染盐碱土壤理化性质的影响,确定合适的通电方式和实验条件;然后,以电动后的土壤作为本底土壤,筛选在电场中活性较高的高效石油降解菌,并进行鉴定,确定其种属;最后,将电动技术与筛选得到的石油降解菌进行结合,开展电动—微生物技术联合修复工作,研究该技术的石油降解效果和可行性。通过研究工作,得到了理想的修复效果。主要结论如下:(1)采用不切换电极和每小时切换一次电极两种通电方式,发现不切换电极的通电方式,电极阳极土壤pH可降到2左右,而阴极会达到13左右,土壤出现严重的酸碱极化现象,不利于土壤微生物生存。而采用切换电极的通电方式,可有效地避免酸碱极化现象的发生,将土壤pH维持在中性水平上。此外,插入电极,会引起土壤温度的升高,一定程度上可以提高微生物活性;同时,插入电极,电解反应会引起土壤水分的损失,需定时补充土壤水分。通过此研究工作,确定切换电极的方式为适宜的实验条件。(2)通过分离、纯化及石油降解实验,共得到两株高效石油降解菌,两者复配,按照10%的接菌浓度,一周内可达到20%的石油降解率,降解效果明显。经形态学观察、16Sr RNA序列分析以及生理生化鉴定实验,判定两者分别是大肠埃希氏菌和蜡状芽孢杆菌。由于两者皆选自电动后的盐碱土壤,因此具有一定的耐电和耐盐性。(3)电动—微生物技术联合,经80天的修复实验,石油降解率可达到28%以上,电极附近降解作用更加明显,可达到35%左右的降解率,微生物组和纯电动组的降解效率分别为15%和22%。电动技术并未改变石油组分的降解顺序,饱和烃和芳香烃最易降解,胶质和沥青质难以降解,但电场对其降解有一定的促进作用。实验过程中需定期补充土壤水分,以维持较高的电场强度。(4)电动—微生物技术应用于石油污染盐碱土壤的修复,修复效果明显,经耗能分析,电动—微生物实验组在整个修复过程中单位质量土壤消耗4.84kw·h电能,成本相对较低,管理运行方便,具有可行性。更多还原

【Abstract】 Oil pollution has always been an important problem affecting the soil environment safety in oil field, and it is also a hot issue at home and abroad.The soil in the oil area of our country, also faces serious problems of salinization, which not only has greatly increased the difficulty of remediation, but also makes the traditional bioremediation insufficient.Electro-bioremediation is a new technology which has been developed in recent years. It has achieved good results in the remediation of conventional oil-contaminated soil.The aim of our work is to study the feasibility of this technology to restore oil contaminated saline soil.This paper takes the saline soil without oil contamination from Shandong Dong Ying island in the Yellow River Delta area as the research object, artificially spiked with oil of 2%,to represent the actual contaminated soil.Research work is mainly divided into three parts.Firstly, study the influence of electric technology on the physical and chemical properties of soil, and determine the appropriate experimental conditions.Then, using the soil in the electric field as the base soil, select and identify strains of high oil degrading efficiency.In the end, combine electric technology and the oil-degrading bacteria selected and study the effect and feasibility of this associated technology.Through the research work, the ideal repair effect is obtained. The main conclusions are as follows:(1)Two power modes were used, one was constant direct current and the other was capable to reverse the polarity of the electric field per hour.It was found that in the former electric field,the soil pH close to the anode could be 2;otherwise,soil near the cathode rose to 13.Whereas by reversing the polarity at intervals, the soil pH was well maintained at neutral levels. In addition, the insertion of the electrodes, caused the increase of soil temperature which, to a certain extent, can improve microbial activity.Also it led to the loss of soil moisture, and needed to regularly add soil moisture.In a word, reversing the polarity of the electrode was the suitable experimental conditions.(2)Through the separation, purification and oil degradation experiment, two kinds of highly effective oil degrading strains were obtained. By adding 10% bacteria liquid to the crude oil medium,the oil degradation rate could reach 20% after one week.By morphological observation, 16 Sr RNA sequence analysis and physiological-biochemical experiments, it was identified that the two stains were Escherichia coli and Bacillus cereus respectively which had a tolerance of electricity and salt.(3)After eighty-day respiration experiment,Electro-bioremediation technology could reach an oil degradation rate of more than 28%.The degradation effect was even more obvious near the electrode area with a 35% oil degradation rate. However the degradation efficiency of Bioremediation and Electro-remediation were 15% and 22% respectively. The Electric technology had not change the oil degradation sequence, that the saturated hydrocarbon and aromatic hydrocarbon were much more easier to be degraded than colloid and asphaltene. However the electric field had a certain role in promoting the degradation of the last two components. During the experiment, it was necessary to supplement the soil moisture in order to maintain a higher electric intensity.(4)The technology of Electro-bioremediation on the oil contaminated saline soil is feasible with a low cost and obvious effect and convenient management.After the energy consumption analysis, it consumed about 4.84kw·h power per kilogram soil during the total experimental process of Electro-bioremediation, whose cost was relatively low.更多还原