【作者】 杨金凤；

【导师】 陈鸿汉；

【作者基本信息】 中国地质大学（北京） ， 地下水科学与工程， 2009， 博士

【摘要】 柴油是目前运输工具中使用最多的燃料之一,在其加工过程、不合理地废物处置以及事故发生时会导致土壤污染,尤其是地下储油罐泄漏造成的土壤污染。生物通风是将土壤气相抽提(Soil Vapor Extraction,SVE)和生物降解结合起来的强迫氧化降解土壤中石油的原位修复技术,因其高效、处理费用和尾气处理成本较SVE有所降低,对地下储油罐泄漏引起的土壤污染治理具有广阔的应用前景。本文通过考虑五个因素(初始油浓度、通风方式、通风孔隙体积数、土壤含水率、C:N:P)的室内正交柱实验和砂箱实验相结合的方法,利用生物通风技术对柴油污染砂土进行修复实验研究,并对砂箱内的土著优势降解菌种进行富集、分离、筛选、分子生物学鉴定,进而评价了其降解性能,主要成果如下:(1)初始油浓度和土壤含水率是影响生物通风修复柴油污染土壤修复效果的最主要因素,C:N:P和通风孔隙体积数次之,通风方式对去除率的影响很小;最佳修复效果的组合为:柴油浓度为40mg油/g土、注气的通风方式、通风孔隙体积数为4 vk·d、C:N:P为100:20:1、土壤含水率为土壤最大持水量的20%;(2)挥发作用主要是由通风孔隙体积数及土壤含水率来影响,残余TPH平衡分布曲线呈类“”型,在总去除率中所占的比例较小,最大的占22.8%,最小的仅占3.8%;重力作用则主要是由初始油浓度、土壤含水率、C:N:P影响,残余TPH平衡分布曲线呈“单峰”型;除通风方式外,四个因素均影响生物降解作用,残余TPH平衡分布曲线呈“双峰”型,生物降解作用在总去除率中所占的比例最大可达68.4%,最小的也占29.4%;(3)在顶部抽提井真空抽提(负压)作用下,砂箱内原有的平衡状态和砂土对柴油的吸附状态被打破,土壤中的柴油污染物(主要是挥发组分)在横向和纵向上发生了迁移和扩散,其中纵向的迁移和扩散较为明显;(4)对砂箱内的土著柴油降解菌进行了富集、分离、筛选,得到4株以柴油为惟一碳源的优势菌株B-1、B-2、B-3、B-4,通过形态学观察和分子生物学鉴定,菌株分别属于微杆菌属(Microbacterium sp.)、短波单胞菌属(Brevundimonas sp.)、假单胞菌属(Pseudomonas sp.,经过系统发育分析,B-3与B-4的同源性有97%,也属于假单胞菌属);(5)在菌株最佳培养条件(pH=7.5,35℃)下,对菌株B-3、菌株B-4的降解特性研究表明不同初始柴油比例下,菌株B-3的降解率明显较菌株B-4的高,在降解柴油方面更有优势,尤其在柴油比例为1.5%时达到了60.98%,比菌株B-4的降解率提高了23.8%。更多还原

【Abstract】 Diesel is one of the most used fuel in transportation. And it causes soil contamination in the course of processing, unreasonable waste disposal as well as the accident occurred, particularly underground storage tank leakage. Bioventing is an in situ forced oxidative soil remediation technology which combined soil vapor extraction (SVE) with biodegradation. It has broad application prospects of soil contamination caused by underground storage tank leakage due to its high-performance, low treatment cost and tail gas treatment cost, compared with SVE. In this paper, the combination method of indoor column in which five factors(initial diesel concentration, venting mode, pore volume number during soil venting, soil moisture content and the ratio of carbon, nitrogen and phosphate) were considered and sand box experiment was used to study the remediation of diesel contamination sand soil by bioventing. In addition, the microbiology experiment was carried out to enrich, separate, screen and identify by means of molecular biology to indigenous dominant bacteria in the sand box, and its degradation characteristics were analyzed. The main results were as follows.(1) Initial diesel concentration and soil moisture content have main effects on the remediation of diesel contaminated soil by bioventing, then the ratio of carbon, nitrogen and phosphate and pore volume number during soil venting. Venting mode has the weakest effect. When 40mg oil /g soil of diesel concentration, air injecting from the bottom of column, 4 vk·d of the pore volume number during soil venting, 100:20:1 of the ratio of carbon, nitrogen and phosphate and soil water content for 20% of the maximum of soil water holding capacity, that would reach a larger removal rate.(2) Volatilization is mainly influenced by pore volume number during soil venting and soil moisture content, the balance and distribution curve of residual TPH is“”type, and the maximun percentage which occupied the overall removal rate of TPH is 22.8%, and the minimum is only 3.8%. Gravity is mainly influenced by initial diesel concentration, soil moisture content and the ratio of carbon, nitrogen and phosphate, the balance and distribution curve of residual TPH is“single peak”type. In addition to venting mode, the other factors affect the biodegradation, the balance and distribution curve of residual TPH is“bimodal”type, and the maximun percentage in the overall removal rate of TPH is 68.4%, the minimum is 29.4%.(3) The original equilibrium state and the sand adsorption of diesel was broken under the vacuum extraction from extraction well on the top of sand box. Diesel contaminants in the soil (mainly volatile components) occurred migration and diffusion in horizontal and vertical direction, and the vertical migration and diffusion was more obvious. (4) Four diesel-degrading strains (B-1, B-2, B-3, B-4) in the sand box, which grew by diesel as only carbon sources were obtained. The results of morphological observation and identification of molecular biology showed these strains belong to Microbacterium sp., Brevundimonas sp., Pseudomonas sp., Pseudomonas sp., respectively. Strain B-3 and strain B-4 have homology of 97% based on phy-logenetic analysis.(5) Under the optimum culture conditions which is pH 7.5 and a temperature of 35℃, degradation characteristics of strain B-3 and strain B-4 were studied. The degradation rate of strain B-3 was obviously higher than that of strain B-4 for different initial diesel concentration. Especially, when the diesel concentration (v/v) was 1.5%, the degradation rate of strain B-3 was 60.98%, increased by 23.8% than that of strain B-4.更多还原