共查询到19条相似文献，搜索用时 140 毫秒
1.
监测式自然衰减（MNA）能够高效低耗地原位修复石油污染地下水的场地,微生物对污染物的降解对MNA过程起到了重要作用。在分析东北石油污染场地地下水中总石油烃（TPH）、电子受体的质量浓度分布和变化规律基础上,划分了微生物功能区。采用溶质通量计算法,对MNA原位修复的潜能及其微生物降解效果进行了评估。结果显示,场地微生物降解正在发生,利用的电子受体不同,划分为Mn、Fe和SO2-4还原区。污染通量模型计算显示：上游地区微生物降解强度不断增强,下游地区微生物降解强度不断降低。监测期内石油烃总量降低了394 kg,微生物降解为自然衰减过程中的主要作用,其贡献率为64%~93%,每个通量断面内微生物降解率为0.18~0.73 kg/d。由此可以证明,MNA可以有效地修复地下水中的石油污染。 相似文献
2.
地下水中污染物具有迁移性和扩散性,会对下游敏感受体造成威胁,目前场地地下水风险评估主要关注人体健康风险,还未能综合考虑地下水污染的整体风险,尤其是忽视了污染物迁移引起的对下游敏感受体的风险。本研究基于“源-径-汇”模型构建了考虑污染物扩散风险的场地地下水污染风险评估的指标体系与风险评估模式。在指标体系构建方面,重点考虑场地地下水的污染源、迁移路径和敏感受体3个方面。在风险评估模式方面,根据场地不同地下水污染状态开展3个层次的风险评估。基于假想的铬污染场地开展了案例分析,设置了地下水污染状态的4种情景,利用Wexler溶质运移模型计算了地下水污染羽的时空变化,并针对地下水污染的不同层次开展了风险评估。结果表明,在场地地下水污染羽未到达场地边界的2种情形中,场地地下水的风险评分分别为4.0,6.2,分别属于低风险与中风险。在场地地下水污染羽到达或超出场地边界的2种情形中,场地地下水的风险评分分别为7.0,8.8,分别属于中风险与高风险。综合而言,本研究构建的方法能够用来对场地地下水进行系统全面的评估和对比,能够根据风险结果对污染场地进行有效的分级管控,为污染场地的风险管控提供技术支撑。 相似文献
3.
某石油污染场地地下水石油烃生物降解的13C、34S同位素证据 总被引：1，自引：0，他引：1
应用稳定同位素技术示踪研究石油烃生物降解作用机理是近年来发展起来的一种有效的新方法。在对某石油污染场地地质和水文地质条件进行详细调查的基础上,分析了场地地下水总石油烃(TPH)、溶解无机碳(DIC)和电子受体(SO24-等)以及稳定C、S同位素等含量的变化规律。研究结果表明:场地地下水不同程度地受到了石油烃类污染,TPH和DIC含量沿地下水流方向逐渐降低,主要电子受体含量和pH相应呈现升高的趋势;场地内污染地下水δ13C值低于未污染地下水δ13C值、且由上游向下游随地下水中DIC含量减少呈逐渐升高的趋势。稳定碳同位素守恒分析结果表明:控制污染场地地下水中DIC含量变化的主要过程为产生CO2的生物降解作用;同时,随着地下水SO24-质量浓度由上游向下游升高,δ34S值逐渐减小。瑞利分馏模型拟合结果证明,场地内发生了以硫酸盐作为电子受体的生物降解反应。 相似文献
4.
以东北某油田石油污染场地多期地下水化学监测数据为基础,分析氯代烷烃自然生物降解中充当第一基质、电子受体、中间产物的水化学组分及相关地球化学参数在污染晕演化的不同时段、不同部位的变化趋势,了解氯代烷烃生物降解的地下水化学响应特征,并以此为依据对污染场地浅层地下水氯代烷烃生物降解程度进行定性评价。结果表明:2010年6月,事故发生约1年之际,在ZK1—ZK3—ZK6纵向剖面上生物降解过程中充当电子受体的水化学组分(SO42–)、第一基质(CH2Cl2、CHCl3)和代表地下水环境的主要理化指标(pH、Eh)从上游到下游均呈递增规律,而相关还原产物(Fe2+、Mn2+、HCO3–)则呈递减规律,这也表明天然微生物降解具有一定的滞后性。2010年6月氯代烷烃天然生物降解评价表明ZK1属微生物降解证据充足;ZK3观测井属微生物降解证据有限;ZK6观测井属微生物降解证据不足。而2011年5月,事故发生约2年之际,封堵污染源后随污染晕中心的向下游迁移,ZK3观测井中生物降解作用逐渐明显,在ZK3—ZK6纵向剖面上地下水化学指标呈现上述响应规律,而ZK1观测井诸多水化学指标经上游未污染地下水的补充更新,逐渐趋向污染前的背景值。 相似文献
5.
某石化污染场地含水层自然降解BTEX能力评估 总被引：1，自引：0，他引：1
地下水污染问题是国家关注的重要环境问题之一,监测与评估含水层自然降解污染物能力是防治地下水污染的基本手段,也是国外地下水中修复技术研究热点课题。以华北平原某石油化工类场地为案例,通过调查场地水文地质条件、土壤及地下水污染现状,监测场地地下水中苯系物(BTEX)浓度及相关化学参数变化,运用微生物水文地球化学方法和水文地质方法,估算了该场地含水层自然降解苯系物量。这一研究成果为评估我国石油类场地地下水污染的自然修复能力提供了实证和基础数据。 相似文献
6.
科学合理的地下水污染修复技术筛选方法对于有效修复受污染地下水体、节约修复工程成本、保护地下水资源、维护生态系统安全和人体健康具有重要意义。以某化工厂遗址早期排污渗坑为目标污染源,在结合水文地质勘查和地下水人体健康风险评价的基础上确定场地受污染地下水修复目标污染物,根据污染物迁移性、降解性、人体健康风险等指标及抽出处理、化学修复、生物修复、渗透反应格栅等地下水污染修复技术特点,使用偏好顺序结构评估法(PROMETHEE)进行修复技术筛选。结果显示,该场地地下水中主要污染物为1,2-二氯乙烷、1,4-二氯苯等有机污染物,其中1,2-二氯乙烷在呼吸吸入条件下的最大致癌风险达9.54×10-7。化学清除、监测自然衰减等四项技术适用于该场地地下水1,2-二氯乙烷修复,化学清除法综合排序分值最高,而在成本优先控制条件下,监测自然衰减技术更为适宜。研究对于我国场地地下水污染调查评估及修复工作具有积极的参考意义。 相似文献
7.
以大量的地下水测试数据为基础,从污染源分布及水文地质条件入手,对黄河下游平原地下水中有机污染物类型及污染程度进行了深入研究。黄河下游平原地下水普遍受到有机物污染并形成多个典型有机污染区,有机物总检出率为35．5％,检出的有机污染物种类达29种,单个样品检出的有机物种类最多达19种,部分有机物含量超过地下水饮用标准,致使地下水质量恶化。地下水污染区的分布及污染程度与污染源的种类和分布具有很好的相关性。 相似文献
8.
重工业区高脆弱岩溶含水层中多环芳烃污染的初步研究 总被引：1，自引：0，他引：1
以西南岩溶地区某市重工业区为研究对象,采集水文地质单元内地下水和土壤样品,利用气相色谱-质谱法（GC-MS)测试美国环保署16 种多环芳烃（PAHs）优控物。初步研究表明,研究区地下水16种PAHs均被检出,浓度为1 135.79～1 361.26 ng/L,以菲、蒽、萘、屈、芘为主;地下水处于中等污染程度,其中苯并[a]蒽、屈、苯并[b]荧蒽、苯并[k]荧蒽4种浓度超过美国EPA2009《国家推荐的优先有毒污染物水质标准》标准;PAHs特征比值显示含水层中的PAHs来源于燃煤和炼焦污染源,与钢铁厂和化肥厂排放的特征有机污染物一致。研究区污染源下游大面积区域地下水已经受到PAHs污染,且出现排泄区PAHs浓度高于径流区的现象,岩溶含水层PAHs的污染主要受两方面影响:一是洼地、裂隙发育,断层破碎带和强风化白云岩等为PAHs在含水层中的运移提供了有利条件,同时污染源区内地下水大量开采加速了污染物向地下水的入渗;二是水电站建坝蓄水发电,江水水位抬高,河岸地下水排泄速度减慢,可能致使岩溶含水层中PAHs的自净能力减弱。生态风险评价显示地下水中菲、蒽、芘、苯并[a]蒽、苯并[b]荧蒽处于重污染风险,应采取措施降低污染风险。 相似文献
9.
邢台市岩溶水污染现状与演化趋势预测 总被引：2，自引：2，他引：0
由于地表水的污染和固体废物的乱堆放,导致邢台市岩溶水多处出现污染现象,且污染范围不断扩大,严重威胁下游水源地的供水安全。本文依据大量水质监测数据,评价了岩溶水的污染现状,采用数值方法预测了污染源继续存在和污染源得到治理两种情况下地下水污染的演化趋势,并分析了其对水源地的影响。预测结果表明:污染源存在时,地下水污染物Cr6+超标浓度等值线将以0.769m/d的速度扩散;在污染源得到有效治理和控制后,地下水污染物超标浓度等值线扩散速度将减少至0.402m/d,可见污染源治理对减缓地下水污染的扩散有重要作用。预测结果可作为选择地下水保护方案和污染治理措施的依据。 相似文献
10.
环境调查研究表明,大武地下水水源地上游邻近的石化厂区出现严重的地下管道石油污染物持续泄漏现象。堠皋－柳杭地段地下水环境在成为集中污染地段的同时,水文地球化学环境也发生了迥然的变化：地下水中电子接受体溶解氧,ＮＯ３＾－末检出,ＳＯ４＾２－呈低值分布。这与地下水中存在微生物降解烃污染物的作用有关。其作用类型包括需氧降解,脱硝降解,脱硫降解以及有Ｆｅ＾３＋参与的降解作用。然而由于该地段需氧降解、脱硝降解、脱硫降懈以及有F3+参与的降解作用。然而由于废地段需氧降解、脱硝降懈难以进行,导致了生物降解污染物的速度降低 其研究意义是提高地下水中电子接受体的浓度．增强微生物的活性,以促进生物降解速度,将有利于含水层中这类污染物的清除。 相似文献
11.
Two biodegradation models are developed torepresent natural attenuation of fuel－hydrocarbon contaminants as observed in a comprehensive natural-gradient tracer test in a heterogeneous aquifer on the Columbus Air Force Basein Mississippi,USA．The first, a first-order mass loss model,describes the irreversible losses of BTEX and its individual components, i．e．,benzene（B）,toluene（T）,ethyl benzene（E）,and xylene（X）．The second, a reactive pathway model,describe ssequential degradation pathways for BTEX utilizing multiple electron acceptors,including oxygen,nitrate,iron and sulfate,and via methanogenesis．The heterogeneous aquifer is represented by multiple hydraulic conductivity（ K） zones delineated on the basis of numerous flowmeter K measurements．A direct propagation artificial neural network（DPN）is used as an inverse modeling tool to estimate the biodegradation rate constants associated with each of the K zones．In both the mass loss model and the reactive pathway model,the biodegradation rate constants show an increasing trend with the hydraulic conductivity．The finding of correlation between biodegradation kinetics and hydraulic conductivity distributions is of general interest and relevance to characterization and modeling of natural attenuation of hydrocarbons in other petroleum-product contaminated sites． 相似文献
12.
汽油污染含水层中芳香烃的自然去除与生物降解特征 总被引：7，自引：0，他引：7
石油烃污染地下水是一个普遍而严重的环境问题.用砂卵石、中粗砂、细砂、粉砂和粘土等在实验室内按照自然界沉积物层序制作了一个含水层物理模型,具有给水、排水、监测、抽提、淋滤与注入等功能.利用该模型开展石油烃污染地下水的特征研究结果表明,苯、甲苯、乙苯和二甲苯(benzene,toluene,ethylbenzene,xylene;BTEX)各溶解组分能够被自然去除,其中甲苯自然衰减的速率系数为0.057 5～0.150 4 d-1,二甲苯为0.068 3～0.104 6 d,乙苯大约为0.047 8 d,苯为O.017 8～0.040 6 d.甲苯与二甲苯容易被去除,然而苯的去除则需要较长的时间.作为BTEX去除反应的电子受体,溶解氧、硝酸盐在需氧或厌氧条件下具有优先利用的机会,而硫酸盐则缺乏优先利用的机会.BTEX溶解组分浓度的降低,加上电子受体浓度的降低,可以表明含水层存在需氧条件与硝酸盐还原条件下的内在生物降解作用.其意义在于通过增加含水层中电子受体的浓度,将有助于内在生物降解能力的增强,从而能够提高含水层中污染物去除的效果. 相似文献
13.
E. R. Rene Ph.D. M. S. Jo S. H. Kim H. S. Park Ph.D. 《International Journal of Environmental Science and Technology》2007,4(2):177-182
Biodegradation has proved to be a versatile technique to remediate benzene, toluene, ethyl benzene and xylene mixtures in contaminated soil and groundwater. In this study, a mixed microbial culture obtained from a wastewater treatment plant was used to degrade liquid phase ethyl benzene and xylene, at initial concentrations varying between 15 to 75 mg/l. Experiments were conducted according to the 2k?1 fractional factorial design to identify the main and interaction effects of parameters and their influence on biodegradation of individual ethyl benzene and xylene compounds in mixtures. The removal efficiencies of these compounds varied between 2 to 90% depending on the concentration of other compounds and also on their interaction effects. A statistical interpretation of the results was done based on the Fishers variance ratio (F) and probability (P) values. Though all the main effects were found significant (P < 0.05) at the 5% confidence level, the interactions between benzene and toluene and benzene and xylene concentrations were also found to be statistically significant and play a major role in affecting the total ethyl benzene and xylene removal. 相似文献
14.
监测自然衰减(monitoring natural attenuation,MNA)技术是目前普遍认可的去除地下水中挥发性有机污染物(volatile organic compounds,VOCs)的技术。但受其修复周期长、监测费用昂贵等因素的影响,实地开展MNA技术修复污染场地具有一定的局限性。基于此,本研究运用多相流数值模拟手段识别了某石油污染场地内典型VOCs污染物(苯、甲苯、萘)在地下水中的自然衰减过程并评估了其自然衰减能力。结果表明:采用TMVOC所建立的多相流数值模拟模型能较好地预测和识别VOCs在地下水中的衰减规律;在研究区中,苯、甲苯和萘由于理化性质差异,在地下水中的污染羽分布特征不同,其自然衰减过程受挥发、吸附和生物降解作用的影响程度也不同;挥发和生物降解作用对VOCs自然衰减的影响程度均为苯>甲苯>萘,而吸附作用对VOCs自然衰减的影响程度为萘>甲苯>苯;在污染源被阻断的前提下,苯、甲苯和萘分别在泄漏发生7.0、6.5和6.0年后通过自然衰减达到理想去除效果。本文研究成果可以为水文地质条件类似的VOCs污染场地MNA修复方案的制定和修复效果评估提供理论支撑。 相似文献
15.
Bettina Anneser Florian Einsiedl Rainer U. Meckenstock Lars Richters Frank Wisotzky Christian Griebler 《Applied Geochemistry》2008
The detailed understanding of in situ biodegradation of petroleum hydrocarbons in porous aquifers requires knowledge on biogeochemical gradients, the distribution of individual redox species and microorganisms. The generally limited spatial resolution of conventional monitoring wells, however, hampers appropriate characterization of small-scale gradients and thus localization of the relevant processes. Groundwater sampling across a BTEX plume in a sandy aquifer by means of a novel high-resolution multi-level well (HR-MLW) is presented here. The presence of distinct and steep biogeochemical gradients is demonstrated in the centimeter and decimeter scale, which could not be resolved with a conventional multi-level well. The thin BTEX plume with a vertical extension of only 80 cm exhibited a decline of contaminant concentrations by two orders of magnitude within a few centimeters in the upper and lower fringe zone. The small-scale distribution of sulfate, sulfide and Fe(II) in relation to the contaminants and elevated δ34S and δ18O values of groundwater sulfate strongly indicated sulfate and iron reduction to be the dominant redox processes involved in biodegradation. High microbial activities and biomass especially at the plume fringes and the slope of chemical gradients supported the concept that the latter are regulated by microbial processes and transverse dispersion, i.e. vertical mixing of electron donors and acceptors. Transverse dispersion therefore was suggested to be a driving factor controlling biodegradation in porous aquifers, but not exclusively limiting natural attenuation processes at this site. Broad overlapping zones of electron donors and electron acceptors point towards additional factors limiting anaerobic biodegradation in situ. The identification of small-scale gradients substantially contributed to a better understanding of biodegradation processes and hence is a prerequisite for the development of reliable predictive mathematical models and future remediation strategies. 相似文献
16.
Modeling in situ benzene bioremediation in the contaminated Liwa aquifer (UAE) using the slow-release oxygen source technique 总被引：5，自引：4，他引：1
Mohamed Mostafa Ahmed Mohamed Nawal E. Saleh Mohsen M. Sherif 《Environmental Earth Sciences》2010,61(7):1385-1399
Dissolved benzene was detected in the shallow unconfined Liwa aquifer, UAE, which represents the main freshwater source for
the nearby residence Bu Hasa camp area. The main source of this contamination is believed to be the rejected water released
from Bu Hasa liquid recovery plant. In this paper, a finite element model (METABIOTRANS) is used to simulate the fate and
transport of the dissolved benzene plume in Liwa aquifer. Different remediation scenarios were simulated in which the slow-release
oxygen source (SOS) technique is utilized to minimize benzene concentrations at the nearest camp supply wells downstream of
the contamination zone. Results of the remediation scenarios show that the highest biodegradation rates occur when the oxygen
source is placed near the plume center; where higher benzene concentrations exist. The nearest oxygen release source to the
contamination zone caused higher stimulation to bacterial growth than further down-gradient oxygen sources. It also exhibited
longer resident time of oxygen in the aquifer; and therefore, yielded higher reductions in benzene concentrations. However,
using one central SOS proved to be insufficient as contaminant escaped laterally. Additional four transverse oxygen sources
were necessary to capture benzene that laterally spread away from the contamination zone. These lateral SOSs were essential
to reduce benzene concentrations at the supply wells that are located at the plume fringes. Finally, it was found that increasing
oxygen release from one source did not always improve remediation; and that using several SOSs with lower release rates could
be a more practical approach to enhance benzene biodegradation in the aquifer. 相似文献
17.
This paper deals with a field experiment, combining the push–pull and tracer tests, conducted under natural gradient conditions
at the international Oslo airport. The studied aquifer, showing very complex hydrogeological settings, has been contaminated
by a jet fuel spill. The tracer solutes—bromide, toluene, o-xylene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene and naphthalene, have been injected into the plume. Their migration
and changes in concentration of the electron acceptors and metabolic by-products have been monitored. Fast removal of both
the non-reactive tracer as well as the aromatic organics has been observed. The tracer pulse could only be detected 2 m downgradient
from the injection points. At this point, toluene and o-xylene have been completely removed, however, trimethylbenzenes and naphthalene have been detected. Their depletion, based
on calculations of available electron acceptors, can, to a large extent, be accounted for intrinsic biodegradation, with Fe(III)
and sulphate reductions as the major controlling processes. 相似文献
18.
Xiaosi Su Hang Lv Wenjing Zhang Yuling Zhang Xun Jiao 《Environmental Earth Sciences》2013,69(6):2091-2101
Biodegradation is one of the main natural attenuation processes in groundwater contaminated with petroleum hydrocarbons. In this work, preliminary studies have been carried out by analyzing the concentrations of total petroleum hydrocarbons (TPH), dissolved inorganic carbon (DIC), dominant terminal electron accepters or donors, as well as δ 13CDIC and δ 34SSO4, to reveal the biodegradation mechanism of petroleum hydrocarbons in a contaminated site. The results show that along groundwater flow in the central line of the plume, the concentrations of electron acceptors, pH, and E h increased but TPH and DIC decreased. The δ 13CDIC values of the contaminated groundwater were in the range of ?14.02 to ?22.28 ‰PDB and ?7.71 to 8.36 ‰PDB, which reflected a significant depletion and enrichment of 13C, respectively. The increase of DIC is believed to result from the non-methanogenic and methanogenic biodegradation of petroleum hydrocarbon in groundwater. Meanwhile, from the contaminated source to the downgradient of the plume, the 34S in the contaminated groundwater became more depleted. The Rayleigh model calculation confirmed the occurrence of bacterial sulfate reduction as a biodegradation pathway of the petroleum hydrocarbon in the contaminated aquifers. It was concluded that stable isotope measurements, combined with other biogeochemical measurements, can be a useful tool to prove the occurrence of the biodegradation process and to identify the dominant terminal electron-accepting process in contaminated aquifers. 相似文献
19.
Experiment simulation study on removal mechanism of BTEX in using river filtration system 总被引：1，自引：1，他引：0
River filtration system is a natural purification process to remove the pollutants in river water and make use of surface water. In this study, a series of experiments were set up with soil column test and static adsorption experiments to simulate the environmental behaviors of BTEX in the river filtration system. It was found that the environmental behaviors of BTEX in the river filtration system included adsorption and microbial degradation. Among the four components of BTEX used in the experiments, the removal rate of xylene was the highest, ethyl-benzene was second, toluene was third, and that of benzene was the lowest. The stability of the structure of benzene was the major contributor for the relatively lower degradation efficiency, and the low removal rate of toluene was due to the impact of adsorption on degradation. By comparison of the results of soil column test and static adsorption experiments, it was found that the soil–water partition coefficient K d of each component of BTEX was higher, the degradation ratio was lower. Compared with the previous study, the results of this experiment showed that when the initial concentration of the each component of BTEX reached 80 mg/L, the mixed pollution of BTEX could be removed by the river filtration system efficiently, and the average removal rate could be over 65 %. As a natural purification, river filtration system could efficiently remove the BTEX mixed pollution in a quite high concentration and protect the ground water from being contaminated. However, its purification efficiency was limited in a certain time range and concentration. It was shown in the later stage of the leaching experiment that the exudation concentration of BTEX increased, at the same time both the concentrations of the two electron acceptors increased to about the initial concentration and kept stable state until the end of the experiment, which revealed that due to accumulation of the concentration of BTEX in the soil column, the microbial activity was inhibited and then the denitrification and sulfate reduction terminated. When the adsorption saturation was achieved and microbial activity was inhibited, BTEX contamination would penetrate through the unsaturated zone and threaten the security of the ground water. 相似文献