西北黄土地区水源水库水―沉积物中石油污染特征及土壤生物修复技

1、 西北黄土地区水源水库水沉积物中石油污染特征及土壤生物修复技术研究专 业：市政工程研 究 生：郭 超指导教师：黄 廷 林 教 授摘 要石油污染的普遍性、复杂性、难降解性，使其受到众多学者的关注。西北黄土地区由于其独特的气候和土壤特征，石油物质对环境的污染方式及其治理手段也具有特殊性。本课题以西北黄土地区石油污染为研究背景，从模拟沉积物中石油污染物静态释放出发，研究不同季节条件下，石油物质在水体和沉积物中的迁移规律，得到相应的静态释放动力学模型；然后以延安地区主要供水水源地王瑶水库为研究对象，系统地研究石油污染物在沉积物中的分布特征，分析水库各支流流域和主体河道的历年污染状况，在此基础上对土壤的

2、生物修复技术进行了系统研究。主要研究成果如下：（1）采用滞膜模型描述沉积物中石油污染物对上覆水体的静态释放过程，其释放动力学方程为：=V AT K W t r e C C 1*K r 和C W *分别代表石油物质的释放速率常数和达到释放平衡时水相中石油物质的浓度，可以通过实验获得。静态实验结果显示，温度对沉积物中石油物质向水体中释放速率有重要影响。当沉积物石油污染强度在320 mg/kg-4792 mg/kg之间时，夏季的动力学参数表达式为：Kr = 5.51 ln(C S0 - 0.25C W * = 0.0003 C S0 + 6.86冬季的动力学参数表达式为：Kr = 3.28 ln(C

3、 S0 + 12.20C W * = 0.0005 C S0 + 4.68据此可以得到夏季和冬季的静态释放动力学方程，然后通过验证，模型可行。 （2） 夏季（温度在30 左右）的静态实验结果显示，当沉积物的石油污染强度C S0分别为320 mg/kg和810 mg/kg时，三次释放平衡后沉积物分层分析显示，对上覆水体的污染起主要作用的有效深度为沉积物上层10 cm左右；当沉积物石油污染强度在1000 mg/kg以下时，污染物对上覆水体的污染可持续时间约为60天。（3）沉积物中石油组分分析结果显示，在检测出的23种石油物质中，除二十八烷、胆固醇以及异三十烷基本不能进入上覆水体外，其余20种物质均

4、可以不同程度的进入水体。碳原子数小于12的烷烃属于易进入水体物质，大于17的烷烃，属于难进入水体物质，在C 12和C 17之间的烷烃是水相石油污染物的主要组成部分。7种多环芳烃中，除二苯并 a,h 蒽较难进入上覆水体外，其余6种物质均属于可进入水体物质，它们对环境和人体健康有重大危害。（4）以陕北延安供水水源地王瑶水库为研究区域，通过对10个断面40个取样位置共400个样品的石油污染含量分析得出，王瑶水库坝前沉积物表层的石油含量在203 mg/kg左右，对上覆水体水质影响较大；研究区域内的5条支流中，支流二水质最好，且流量较大，对减轻主河道污染起积极作用；其余4条支流流域污染均较为严重，其中，

5、支流三和支流四流域内石油污染状况最为严重，对水库污染的贡献最大，支流一和支流五由于水量小对主体河段影响较小，但其污染状况有日益加深的趋势；污染较严重的支流三和支流四入口位置表层沉积物中检测出3种烷烃，9种多环芳烃，因此，王瑶水库存在潜在的多环芳烃污染。（5）在实验室好氧条件下，通过驯化筛选，从安塞油田废弃井场石油污染土样中富集分离出5株高效石油降解菌，经形态观察和生理生化试验初步鉴定，它们分别属于假单胞菌属（Pseudomonas sp. ）、邻单胞菌属（Plesionmonas sp. ）、黄单胞菌属（Xanthomonas sp. ）和动胶菌属（Zoogloea sp. ）；5株高效菌当p

6、H 值在7左右，N / P比在4左右，石油污染强度在1000-1500 mg/L之间时，均可获得较高的石油去除率，它们最佳的氮源为NH 4NO 3，但5株高效菌各自适宜的初始pH 值、N / P比和石油污染强度范围有所不同。（6）在西北黄土地区历时80天现场土壤修复试验结果显示，污染物强度对微生物的活性有重要影响。在低污染强度下土壤中的石油去除率较高，但会导致微生物由于碳源不足而生长受到限制；高污染物强度下，土壤内pH 值下降程度大，对微生物产生毒害，并抑制其生长。（7）在石油土壤的生物修复试验中，添加营养物质可以显著提高微生物生长速率和石油降解率；短期内通过加菌操作可以获得较好的石油去除效果

7、；单一的翻耕操作导致土壤中含水率降低，抑制微生物生长，石油降解率下降。关键词：西北地区；石油；沉积物；释放；生物修复基金资助：本课题的研究得到国家自然科学基金项目（编号：50378077）的资助西安建筑科技大学博士学位论文Petroleum Pollution Characteristics of Water - SedimentsSystem in Source Water Reservoir and Bioremediation Researchof Oil Contaminated Soil in Northwest Loess AreaSpecialty: Municipal Engi

8、neeringAuthor : Guo ChaoAdvisor: Pro. Huang TinglinABSTRACTPetroleum pollution is widespread, complex, and disdegradational. Special climate and soil characteristics result in the differences of petroleum pollution style to environment and petroleum pollution treatment means in Northwest Loess Area.

9、 The study was under the background of petroleum pollution in Northwest Loess Area. By simulating the static release of the petroleum pollutants in sediments, which meaned that petroleum transferred from sediments to superior water body, the transference rule of petroleum in water body and sediments

10、 and static dynamic models was obtained under the different season. The distribution characteristics of petroleum pollutants in sediments and yearly oil contaminated states of branch catchment basin and main waterway were studied at Wangyao reservoir, which was the main water supply source of Yanan.

11、 And the bioremendiation technology of oil contaminated soil was systematically studied. The main research contents and results were as follows:(1 The static release process of petroleum pollutants in sediments was described by stagnant film model. The release dynamic equation was as follows:=V AT K

12、 W t r e C C 1*K r and C W *, which were obtained by static experiments, were release rate constant of petroleum pollutants and petroleum concentration in aqueous phase under release balance respectively. Temperature was a main factor which influenced the release rate of petroleum pollutants in sedi

13、ments. When the oil contaminated concentration were between 320 mg/kgand 4792 mg/kg, the summer dynamic parameters equations were as fllows:Kr = 5.51 ln (C S0 - 0.25C W * = 0.0003 C S0 + 6.86The winter dynamic parameters equations were as fllows:Kr = 3.28 ln (C S0 + 12.20C W * = 0.0005 C S0 + 4.68Ac

14、cording to these equations the summer and winter dynamic models were established respectively. And the feasibility of models was verified.(2 The results of the static release experiments in the summer, when the temperature was about 30 and the oil contaminated concentration was between 320 mg/kg and

15、 810 mg/kg respectively in sediments, showed that the sediments effective depth, in which the petroleum pollutants affected the water quality of superior water body, was about 10 cm by three layer analysises of sediments after release balance, and showed that the second pollution of sediments lasted

16、 for about 60 days, when oil contaminated concentration was below 1000 mg/kg in sediments.(3 The results of petroleum component analysis in sediments showed that there were 23 kinds compounds. Besides of octacosane, cholesterin and squalane, the rest 20 kinds could enter the superior water body. The

17、 substances whose carbon number was below 12 easily entered the water body, and the substances whose carbon number was over 17 difficultly entered the water body. The substances whose carbon number was between 12 and 17 were main components of petroleum pollutants in water body. Among the 7 kinds po

18、lycyclic aromatic hydrocarbon, besides of dibenzo a, h anthracene, the rest 6 kinds, which had great dangers to environment and human health, could enter water body.(4 The Wangyao reservoir, the main water supply source of Yanan, was studied. All of the results were gained by 400 samples at 40 posit

19、ions on 10 cross-sections. The petroleum concentration of surface layer sediments was about 203 mg/kg at ante-dam in Wangyao reservoir. There were 5 branches. The branch two whose water quality was the best and water quantity was most great, improved the main waterway pollution. The rest branch catc

20、hment basins were severely polluted. The branch one and five, whose water quantity were little and pollution station had more and more serious tendency, had the little influence on the main waterway water quality. But the branch three and four, whose water quality wasworst and water quantity was gre

21、ater, had the serious influence on the main waterway water quality. There were three kinds diolefine and 9 kinds polycyclic aromatic hydrocarbon in surface sediments, which meaned that the Wangyao reservoir might be polluted by the polycyclic aromatic hydrocarbon, at the entrance position of the bra

22、nch three and four.(5 In laboratory the 5 highly efficient petroleum-degrading strains were screened under aerobic condition from oil contaminated soil obtained from the abandoned well site at Ansaioilfield in Yanan. The 5 strains were GX1 （Pseudomonas sp. ）、GX2（Plesionmonas sp. ）、GX3（Xanthomonas sp

23、. ）、GX4（Pseudomonas sp. ）and GX5（Zoogloea sp. ）., The high degradation rates of the 5 strains were obtained, when the pH value was about 7, the N / P ratio was about 4 and the petroleum concentration was below 1000 mg/L. The optimal nitrogen source was NH4NO 3. But the eligible ranges of the initial

24、 pH value, N / P ratio and the petroleum concentration were different.(6 The results in the field experimentation that lasted for 80 days in Northwest Loess Area showed that the petroleum concentration had great influence on the activity of microorganism. The higher oil removal efficency rate was ob

25、tained at the lower petroleum concentration, but the growth of microorganism was limited because of the absence of carbon source. At the higher petroleum concentration, the decreasing extent to the pH value in the soil was too large and the growth of microorganism in the soil was inhibited by toxicu

26、m.(7 In the field experimentation, adding nutrient was good to the growth of microorganism and the oil removal efficency rate. By seeding highly efficient petroleum-degrading strains, the higher oil removal efficency rate was obtained in the short term. The growth of microorganism was inhibited and

27、the oil degradation rate decreased because the simple plowing induced decreasing of water content in the soil.Key words: northwest area, petroleum, sediments, release, bioremediationSponsor: This study is supported by the National Natural Science Foundation of China( NSFC ( NO. 50378077 目 录目 录.VII第1

28、章 绪 论.11.1石油污染物概述.11.1.1基本性质.11.1.2石油类污染物的来源与分布.11.1.3石油类污染物的危害.31.2 西北地区石油污染物在环境中的迁移转化规律.41.2.1西北地区石油污染特征.41.2.2石油类污染物在环境中赋存状态.51.2.3水-沉积物界面石油物质的吸附和释放.71.3王瑶水库石油沉积物特点.121.3.1沉积物的形成及其特点.121.3.2水库泥沙和石油污染物传输.121.4石油沉积物的生物修复技术.131.4.1生物修复技术概述.141.4.2 生物降解速率影响因素分析.161.4.3生物修复研究现状.181.5课题研究背景.191.5.1课题来源

29、.191.5.2课题研究的主要内容.20 参考文献.20第2章 石油类污染物静态释放规律研究.282.1材料与方法.282.1.1实验装置.282.1.2标准油和标准溶液配置.292.1.3样品的制备.292.1.4 测定方法.292.1.5实验方法.312.2静态释放动力学研究.312.2.1沉积物中石油污染物的释放动力学模型.312.2.2石油物质静态释放模型季节性变化.332.3沉积物中石油物质迁移规律.402.3.1沉积物中石油含量变化.402.3.2沉积物中石油组分分析.422.4沉积物中石油污染物对上覆水体水质污染的时效性研究.462.5本章小结.47 参考文献.48第3章 王瑶水

30、库水体沉积物中石油污染特征分析.503.1王瑶水库概况.503.2沉积物样品的采集、测定及分析.503.2.1采样点的布置、样品采集及保存.503.2.2 分析方法.513.3水库沉积物中石油污染物分布状况.513.3.1 坝前区域内沉积物中石油含量分析.513.3.2支流交汇区域沉积物中石油含量分析.553.3.3研究区域内沉积物石油污染分布特征.623.4沉积物石油组分分析.633.5本章小结.65 参考文献.65第4章 石油污染土壤生物修复研究.674.1石油降解菌种的筛选.674.1.1材料与方法.674.1.2菌种驯化和分离.684.1.3高效菌种的筛选与鉴定.694.1.4高效降解

31、菌最佳生长条件研究.714.2生物修复中试试验研究.764.2.1试验基地的建立.764.2.2试验方案和装置设计.774.2.3石油污染强度对生物修复过程参数的影响.784.2.4 添加营养物质条件下操作方式对石油降解的影响.824.3 本章小结.87 参考文献.87第5章 结论与建议.895.1结论.895.2主要创新点.915.2存在的问题及建议.92攻读博士学位期间发表的论文和参加的科研工作.93致 谢.94第1章 绪 论1.1石油污染物概述1.1.1基本性质石油是由古代水生生物演化而来，呈黑色或深棕色，密度为829-896 kg/m3，主要由烃类物质组成。其中，烃类物质占95%-99

32、.5%（碳、氢元素），其它元素（硫、氮、氧）仅占0.5%-5%。烃类化合物性质稳定，不溶于水，主要为烷烃、环烷烃、芳香烃三大类，也有少量的烯烃（其含量极低，可以忽略），它的构成直接影响石油的物理和化学性质，其组分的物理性质见表1.11-3。非烃类化合物显极性，易溶于水，对环境的危害大4-6。表1.1石油中烃类物质的物理性质1序号成份 密度（g/mL） 沸点（） 分子量 1直链烷烃（C 6-C 12） 0.66-0.77 69-230 86-170 2直链烷烃（C 13-C 25） 0.77-0.78 230-405 184-352 3环烷烃（C 6-C 12） 0.75-0.9 70-230

33、84-164 4环烷烃（C 13-C 23） 0.9-1.0 230-405 156-318 5单环芳香烃（C 6-C 11） 0.88-1.1 80-240 78-143 6 多环芳香烃（C 12-C 18） 1.1-1.2 240-400 128-234 石油中约200种化合物属于非烃类，其余为烃类。非烃类化合物由碳、氢、硫、氮、氧或金属原子构成。高分子量非烃化合物主要为胶质和沥青质，属于芳香系列和环烷-芳香系列；中-低分子量非烃化合物主要为含硫化合物（如元素硫、硫化氢、硫醇、硫醚、二硫化物、噻吩及其同系物等）、含氮化合物（如咔唑类、吡啶类和喹啉及其烷基衍生物等）、含氧化合物（如与 -CO

34、OH官能团有关的脂肪酸等有机酸、酚和萘酚等羟基芳烃化合物、苯并呋喃等呋喃衍生物、醇、醛、酮、醚以及多官能团芳香化合物）7-10。1.1.2石油类污染物的来源与分布一、石油类污染物的来源石油工业中含油污水、钻井废弃泥浆、石油污染土壤和烃类污染四大污染是环保工作的热点问题。污染产生与石油工业的生产工艺和开发阶段有直接关系，同时也由于石油工业中内容多、工序差别大、施工复杂、管理水平高低不一、设备配置不一致以及环境状况的差异，使污染源的寻求比较困难。图1.1表示石油工业一般条件下造成污染的污染源情况，有助于掌握石油工业污染源形成的一般规律，从而实现源头控制污染的目标。石油开采过程中不同作业期所产生的石

35、油类污染物也不同。如在钻井作业中主要产生含有石油类污染物的钻井废水及含油泥浆，采油作业中主要为采油废水、洗井废水和落地原油11-13，原油集输及储存过程中主要为含油废水和固体废弃物，事故污染主要包括落地原油、原油泄漏14-16。 图1.1 石油工业污染源的构成 二、石油类污染源的分布特征 石油污染源总体上具有地域广阔、点源分散性、面源区域性以及与地方其他污染源的交叉性等特点17。我国的石油资源几乎遍布整个国土区域，在东北、西北、华北、中原、西南、华中以及东部沿海各地均有石油资源18-19；每个油田内含有很多个独立的点污染源，其分布极为分散；降雨径流是导致石油面源污染的主要途径，它的污染广阔性大

36、、分散性强，几乎遍及整个区域；石油工业与其它行业息息相关，也使得其污染会带个其他相关行业造成交叉污染20。这些分布特征最终导致石油污染控制难度更大，给环境保护工作者提出了更高要求。1.1.3石油类污染物的危害石油类物质对环境污染从污染源产生途径可分为两类：一类是石油泄漏造成的事故污染，其危害性具有快、强等特点；另一类是在石油工业制造和使用过程中长期石油污染物的积累产生的毒性效应，其危害性不显著、但后果严重。从污染源组成物质上看，石油中的烷烃类物质含量远高于芳香烃类含量，但后者强烈的致癌、致畸作用更受到广泛关注。石油类污染物的危害表现在对水生生物、土壤及植物、动物、人体以及饮用水的毒害作用21-

37、22。石油在水体中主要以浮油、溶解油、乳化油等形式存在，它通过影响水体复氧功能，直接触杀，或通过萃取海水中的氯烃等途径，影响水生生物的生理活动、繁殖23-25。对土壤的危害主要发生在油田区，它通过影响土壤的通透性、消耗大量的氧使植物腐烂直至死亡或使植物中毒（见表1.2）26-27。低沸点饱和烃容易引起动物麻醉、昏迷，甚至死亡。各种石油蒸馏物会引起人体产生痉挛、昏迷、眩晕、嗜眠等，严重伤害人体的肺、胃肠、肾、中枢神经系统和造血系统，表1.3列出了人类对各种石油类物质摄入浓度限值，另外，人体由于食用了各类有毒的产品，也会造成严重危害；石油类污染物对人体的危害还表现其致突变和致癌变特性上，如芳香烃中

38、的多环芳香烃及其衍生物（PAH ）28。水源水中石油物质会使水处理过程中絮体难于沉降、过滤效果差、滋生细菌、产生消毒副产物，最终对人体健康构成潜在威胁29。表1.2 土壤中石油物质的含量对水稻生长的影响石油物质含量（mg/kg）水稻反应 400-600矮化减产 1000严重矮化表1.3 人体摄入各类石油烃物质最高限值28烃类 浓度（mg/L） 烃类 浓度（mg/L）甲苯浓缩液60号溶液 90 涂料用石脑油高芳烃溶剂 26 橡胶溶液40号稀释剂 25 高环烷烃溶剂脱臭煤油 14 混合二甲苯苯 10 80号稀释剂1.2 西北地区石油污染物在环境中的迁移转化规律1.2.1西北地区石油污染特征自上世纪

39、80年代以来，石油工业已经成为西北地区的支柱产业。但受地区经济和管理水平的限制，各地方的石油工业存在开发层次多，管理水平、技术水平参差不齐，油田渗透率低、面积大，水土流失严重等问题30-31。这些问题最终导致产生大量的含油废水、且其含油浓度较高，较大的油田面积使各个点源污染遍及个河谷、沟岔、山峁，污染范围较大，加上西北地区自身植被差、水土流失严重，使石油面源污染加剧了对当地水环境的影响32。一、点源污染状况根据资料和调查结果，在西北延安地区，除长庆油田作业过程中基本没有废水外排外，其他地方油田油井由于工艺落后、油井分散性大，产生大量含油废水和土壤。据报道，地方油田单井平均每天产生的废水量为2吨，其含油量高达7500 mg/L；仅有50%采油废水经过汽车运输后到隔油池进行处理，而且经过处理后的出水含油量高达32 mg/L，对周边环境污染仍然很大33。二、面源污染状况石油面源污染指在降雨时期，由于采油井场的土壤污染引起的河流水质污染。资料表明，西北延安地区的井场污染程度很严重，例如在储油罐附近，地表以下12 16 cm