【作者】 王博；

【导师】 武晓峰；

【作者基本信息】 清华大学 ， 水利工程， 2010， 硕士

【摘要】 土壤和地下水的污染具有较强的隐蔽性,由于长期缺乏关注和有效保护,我国土壤和地下水污染的情况仍在不断发展。作为典型的储油设施,加油站是土壤和地下水中有机污染的主要来源之一。地下输油管线的破损或地下储油罐的锈蚀使石油在土壤和地下水中发生渗漏,具有较大毒性的石油烃威胁着人体健康。目前,我国对加油站石油污染修复技术的研究较少,缺乏工程实践经验和完善的技术体系。本研究以北京市某加油站作为研究对象,以石油烃中常见的挥发性有机污染物质BTEX(即苯(benzene)、甲苯(toluene)、乙苯(ethylbenzene)、二甲苯(xylene))作为典型目标污染物,建立了加油站石油污染由现场监测至修复技术设计的完整流程。本研究为石油污染场地的监测与修复提供了技术示范,进行了技术储备。本研究对传统的地下土壤气相取样技术进行了改良,并利用改良后的技术对所研究加油站实施了现场监测,获得了各施测点位包气带中的BTEX气相浓度。由于BTEX以气相、吸附相、NAPL相和溶解相等多相形式共存于包气带中,本研究对BTEX多相平衡浓度进行了计算;并以国内外土壤环境质量标准为评价依据,判断出场地受到污染、污染程度较轻,污染重点治理区域为G3点位附近;还分析了该评价的局限性。本研究全面调研了自然衰减技术(Monitored Natural Attenuation,MNA)的机理,对MNA技术各种主要的非生物过程和生物过程逐一进行了分析;还对包气带中有机污染物生物降解的特殊性进行了分析,即包气带中有机污染物的生物降解以需氧呼吸为主,且符合一级衰减规律C = C0 e?kt,同时利用一级衰减规律对场地包气带中污染物生物降解的趋势作出了评价。土壤气相抽提技术(Soil Vapor Extraction,SVE)能够对被石油污染的包气带进行有效修复。本研究使用AIR3D软件,结合加油站场地条件与石油污染现状,建立了单井均质稳态数值模型,从抽提影响范围和经济成本两个方面综合考虑,对抽提真空度和花管长度等对SVE修复效果有重要影响的抽提井参数进行了模拟计算,提出了SVE的设计方案。更多还原

【Abstract】 The soil and groundwater have become more contaminated gradually in our country because of the long-term lack of attention and effective protection due to the concealing of the contaminants in the subsurface. As the typical facility of petroleum storage, the gasoline station is one of the main sources of organic contaminants in the soil and groundwater. The seepage of petroleum in the soil and groundwater can be caused by the breakage of petroleum pipelines or tanks which are buried in the subsurface, and the human’s health is threatened by the toxic petroleum hydrocarbons. Fewer studies have focused on the remediation of the contaminated gasoline station by petroleum presently in our country, so there is less practical experience and inperfect technology system. Regarding a gasoline station in Beijing and the BTEX (benzene, toluene, ethylbenzene and xylene) which are common volatile organic contaminants in the petroleum hydrocarbons as the study object and the typical contaminants respectly, this study has established an entire treating procedure for the contaminated gasoline station from the field monitoring to the design of remediation technology. This study has set a technical demonstration for the monitoring and the remediation of a contaminated site by petroleum.This study has amended the conventional technology of soil gas sampling in the subsurface, conducted the field monitoring in the gasoline station and obtained the BTEX gas phase concentrations of the sampling locations in the unsaturated zone. Because the 4 phases of BTEX which are gas phase, adsorbed phase, NAPL phase and dissolved phase usually coexist in the unsaturated zone, this study has calculated the multi-phases equilibrium concentrations. Based on the environmental quality standards for soils at home and abroad, this study has concluded that the gasoline station has been slightly contaminated and the region nearby G3 location should be the major remediation site. This study has also implied the limitation of such a soil environmental quality assessment.This study has surveyed the mechanism of monitored natural attenuation (MNA) overall, and analyzed all kinds of major abiotic processes and biotic processes. This study has also indicated the specialty of the biodegradation of the organic contaminants in the unsaturated zone, that is, the aerobic respiration is the major biodegradation form and the process accords with the first-order decay law 0C = C e?kt. Then the trend of the biodegradation of the organic contaminants in the unsaturated zone of the site has been evaluated by the first-order law. Soil vapor extraction can restore the unsaturated zone which has been contaminated by petroleum effectively. According to the site conditions and contaminated situation, this study has utilized the software AIR3D which can simulate the soil gas flow in the unsaturated zone to set up a single well, homogeneity and steady state model. Considering both the extraction influence area and the cost, this study has designed the extraction vacuum and the screen length, which are the major parameters of a SVE system, based on the results of the numerical simulations.更多还原