Pumping-rate control for contaminated groundwater with VOCs by using fuzzy inference model

In this paper, a new method is proposed for the remediation of contaminated groundwater. The method is based on fuzzy inference and risk evaluation. The effectiveness of the presented method is assessed in numerical simulations. The main results of the study are as follows: 1) A pump-and-treat control algorithm was proposed by using the fuzzy inference and the human health risk calculation model, 2) It was found that applying the proposed algorithm was likely to reduce the pumped quantity, and 3) It was found that the proposed model can be used to notify residents of the human health risk; the model is based on the ASTM RBCA model for residents. A new fuzzy control system for contaminated groundwater can be used as a useful model for characterising the effects of contaminants on human health and providing helpful information on the human risk assessment of the contaminated groundwater site.     

Uncertainty analysis of groundwater model based on data assimilation北大核心CSCD

黑河流域中下游地下水系统受上游冰冻圈融水和降雨的补给,由气候变暖导致的冰冻圈萎缩致使中下游地下水系统的稳定性面临更多的风险。地下水模型是地下水系统稳定性评估的有效手段,但是地下水模型参数往往存在较大的不确定性。为此,本文提出了基于数据同化算法的不确定性分析方法,通过包含观测资料信息减小模型不确定性。采用所提方法分析了(基于MODFLOW构建)黑河流域中游地下水模型中13个参数的不确定性,讨论了算法超参数的影响及其最优取值,分析了地下水模型参数的不确定性。实验结果证明数据同化算法可有效减小地下水模型参数的不确定性,观测资料的种类与数量对参数不确定性的减小起到重要作用;不同地下水模型参数的不确定性不同,地表水与地下水相互作用频繁的区域参数不确定性较大;含水层渗透系数、含水层给水度以及灌溉回流系数对模型输出的地下水位输出影响显著,河床水力传导系数对模型输出的河流流量影响较大。本研究将为地下水研究提供更加可靠的模型方法,为西北内流区地下水哺育的绿洲生态系统稳定可持续研究提供重要支撑。     

构建地下水污染防护与修复管理中的综合决策系统(英文)

试图阐述如何对一个国家或地区在可持续发展国策下优化资金及人力配置,采取必要的防护和修复地下水污染的可行措施,从而最大限度减少由地下水污染对人类及生态可能产生的危害。提出了一个管理地下水污染防护与修复的综合决策系统框架。该系统框架的构筑是基于资金及人力的有限性、系统优化原理、地下水污染对人类及生态可能产生的危害,地下水防护与修复的难度或费用高低、地下水保护的效益与价值,以及同时考虑满足可持续发展要求。其中,由不同地下水污染防护与修复措施产生的地下水污染危害减少量构成了优化分析的目标函数。有限资金的最佳配置是通过使目标函数的最大化,并满足所有的管理、资源等限制条件加以确定的。还就执行该决策系统框架中所需完成的主要任务及步骤给予简述,并就几个相关的前沿性问题加以探讨。     

基于单体多维稳定同位素分析的地下水有机污染研究进展

单体多维稳定同位素分析技术(MD-CSIA)能够更加深入地解析地下水有机污染物的衰减过程,为监测目标污染物原位修复效果和探究其微生物降解机制提供技术支持。文中分析了MD-CSIA技术在地下水有机污染研究中的应用动态,讨论了利用该技术进行有机污染物来源辨识及其迁移转化过程示踪的可行性,着重指出该技术可有效判识有机污染物在地下水中的转化途径并量化其转化程度,最后预测了MD-CSIA技术应用研究的发展趋势。     

Soil composition at the aquifer level,groundwater quality and the presence of Dehalococcoides ethenogenes at Dover AFB

Chlorinated solvents are among the most common groundwater pollutants globally. A common method to remediate this groundwater pollutant is through bioremediation. One of the most important bacteria that remediation workers use in this remediation is Dehalococcoides ethenogenes, which are the only dehalogenating bacteria with the capacity to break down these contaminants to the non-chlorinated compound, ethylene. While much is known about these bacteria in the laboratory, little is known about their natural habitat. In this experiment, eight sites on Dover Air Force Base were selected based on the larger CERCLA Closeout project; 2.54 cm wells were installed and groundwater samples were collected. These sites monitored groundwater quality parameters: temperature, pH, dissolved oxygen, and oxidative reduction potential. Additionally, samples were also analyzed for the contaminants: tetrachlorethylene, trichloroethylene, and vinyl chloride. The presence of vinyl chloride is an indicator of Dehalococcoides ethenogenes. Soil samples from the aquifer level were taken from each site as well and soil particle texture was assessed using the Bouyoucos hydrometer method. The objective of this experiment was to determine if there was a relationship between clay particles at the aquifer level, groundwater quality, and the presence of Dehalococcoides ethenogenes.     

地下水污染场地污染的控制与修复

我国存在大量的地下水污染场地,给地下水资源的使用带来了严重威胁。将地下水污染场地划分为4大类,15个亚类,为制定不同地下水污染场地的管理、控制和修复规定提供了依据;对地下水污染防治规划的内容和方法技术进行了论述。提出了建立地下水污染的预警系统,为污染的预防奠定基础;介绍了地下水污染的控制与修复技术,并对地下水污染防控和治理的基本原则进行了探讨。     

Applying numerical modeling for designing strategies of effective groundwater remediation

Selection of effective groundwater remediation scenarios is a complex issue that requires understanding of contaminants’ transport processes. The effectiveness of cleanup measures may be verified by fate and transport numerical modeling. The goal of this work was to present the usefulness of fate and transport modeling for planning, verification and fulfillment of effective groundwater remediation methods. Selection methodology was developed, which is based on results of numerical flow and transport modeling. A field site located in south-east Poland was selected as a case study, in which groundwater contamination of trichloroethene and tetrachloroethene was detected. The results indicated that “pump and treat” was the most effective among the studied remediation methods, followed by permeable reactive barrier and in situ chemical oxidation. Natural attenuation-based remediation was demonstrated to be the least suitable, as it requires the longest time to reach predefined remediation goals, principally due to low sorption capacity and unfavorable hydrogeochemical conditions for biodegradation. Fate and transport numerical modeling allowed simulating different remediation strategies, and thus the decision-making process was facilitated.     

地下水污染场地风险管理与修复技术筛选

国际上对于地下水污染场地的控制与修复研究已经取得了许多成果,已有成功的修复实例。我国虽然起步晚,但非常重视地下水污染的防治,开展了全国范围的地下水污染调查,并进行了地下水污染的防治规划。地下水污染的控制与修复已经逐渐进入示范性研究阶段。面对地下水污染场地风险管理的不同方法,以及众多的污染修复技术,如何制定风险管理策略,如何在各种各样的修复技术中筛选合适的技术或技术组合,对于地下水污染场地的防治具有非常重要的意义。笔者分析了发达国家地下水污染风险管理策略,结合在地下水污染场地研究方面的经验,对一些主要的地下水污染修复技术进行了分析论述,提出了考虑污染物特征、场地水文地质条件的地下水污染修复技术的筛选过程和方法。     

Possible impact of shallow interfluve traps on groundwater remediation

Shallow stratigraphic traps exist in certain geologic environments, which might complicate groundwater remediation efforts. Too often, pump-and-treat remediation wells are installed in geometric patterns designed to maximize cleanup operations. If, however, shallow stratigraphic traps are present, certain contaminants may be locally trapped and thus missed during cleanup operations. Alternatively, if shallow stratigraphic traps are delineated prior to location of cleanup wells, fewer wells may be needed for remediation. For example, a single well located at the trap apex, coupled with a single injection well, might be sufficient if: (1) all contaminants were contained in the trap, and (2) the trap was not laterally extensive. Interfluve stratigraphic traps are formed when braided outwash sands are subsequently covered by backswamp or lacustrine clay deposits. Such traps are common near-surface features of the valley train deposits of the Lower Mississippi River Valley and have relief of a few tens of centimeters to perhaps in excess of 10 m. Interfluve traps are also expected to commonly occur in many glaciated regions. Due to channel migration during backswamp clay deposition, and differing thicknesses of clay cover, it is unlikely that all interfluve traps can be delineated by a single method. Therefore, several geological techniques that might be useful in delineating shallow interfluve traps are briefly discussed here, as well as potential complications in using the described methods.     

Chemical contaminant reactions and assessment of soil cleanup levels for protection of groundwater

About 70 percent of hazardous waste sites listed in the National Priority List (NPL) have some groundwater contamination that may require remediation. Such remediation is inadequate if the unsaturated soils above will continue to act as a source of groundwater contamination. Consequently, for most of these sites, it becomes necessary to determine what the cleanup levels for contaminants in soils should be so that subsequent contribution of contaminants from these soils to groundwater would not exceed groundwater protection levels. Representation of the dynamics of interactions between contaminants and soils is very complex, requiring among others, a thorough understanding of the chemical processes that influence the behavior of the contaminant once it enters the subsurface. Because of such complexities, environmental professionals frequently utilize methods with very simple assumptions that tend to err on the conservative side. While the public may feel protected, the needless spending of dollars could be avoided if attempts are made to incorporate, where possible, such complexities in the modeling efforts so that the system is represented as accurately as possible.     

电化学-水动力循环耦合井内生物反应器去除地下水中苯胺

为使含水层中苯胺污染的原位修复过程高效安全且不产生二次污染,提出了一种电化学-水动力循环下的井内生物反应器修复地下水中苯胺的方法.在水动力循环系统的驱动下,评价了苯胺在水动力循环系统的挥发情况并且通过电化学手段提供氧气,井内生物反应器提供修复载体,在砂槽模拟的含水层体系中开展井内生物反应器降解苯胺的修复实验,并对生长曲线及含水层中苯胺修复进行了模拟.289 h的修复使体系内苯胺平均浓度从298 mg/L降低到132 mg/L,去除率为56.5%.运行过程中,监测点苯胺平均浓度在48 h内去除速率为1.10 mg/（L·h）,48~72 h内去除速率为0.85 mg/（L·h）,72 h到289 h内苯胺去除速率维持在0.65 mg/（L·h）,氧化降解逐步减弱.该过程符合Michaelis-Menten方程,反应速率为:-6.71×10-7/（15+t）2.该修复系统是基于地下水动力循环技术的改进,有望应用于有机污染地下水修复.      

A GIS raster technique to optimise contaminated soil removal

A geographic information system (GIS) raster technique has been developed and used interactively with remediation designers to evaluate the optimum extent of excavating soil contaminated by chlorinated solvents. The technique and the results of its application are presented. The site was a former chemical storage plant for acids and solvents. Two distinct solvent plumes were detected within the ground using a photo-ionisation detector. The solvents were found to be dissolved in the groundwater and migrating in the general direction of groundwater flow. A remediation strategy was proposed involving the localised excavation of contamination ‘hot spots’ followed by the implementation of a groundwater remediation system. A number of excavation options were discussed and the GIS raster technique was developed to evaluate these options in terms of contaminant removed and excavation cost.

The plumes were initially mapped using a triangular irregular network (TIN). These TIN models were rasterised to produce a regular grid of rectangular cells, each cell having a value relating to the concentration of contaminant at that spatial point. The proposed excavation zones were then overlaid on to the raster models as masks. The relationship between the value of contaminant concentration of cells within the mask (or excavation zone) and the total value of contaminant concentration of cells within the solvent plume was used to determine the efficiency of the excavation.

The excavation options were compared taking into account the percentage of the contaminant plume removed, the excavation area (soil volumes) and related costs. Once the GIS raster technique had been developed, it proved very quick to rerun the analysis for the other excavation zones. The optimum excavation zone, based upon cost and contaminant recovery, was found for the site. The technique helped by targeting the worst area of contamination and provided the client with a cost-benefit analysis of the different remediation options.     

Characteristics of Oil Contamination and Numerical Modelling of Its Transport in Fracture-Karst Water in Zibo City,China

In this paper, the hydraulic characteristics of the fracture-karst aquifer and the distribution patterns of petrochemical contaminants are studied. Then, a numerical model using the mixed Eulerian-Lagrangian approach is constructed to predict the distribution and transport of petrochemical compounds in groundwater. The results of numerical modelling and sensitivity analysis show that it may be a workable way for aquifer remediation to combine contamination sources control and capture zone establishment.     

Long-term performance evaluation of zero-valent iron amended permeable reactive barriers for groundwater remediation – A mechanistic approach

Permeable reactive barriers (PRBs) are used for groundwater remediation at contaminated sites worldwide. This technology has been efficient at appropriate sites for treating organic and inorganic contaminants using zero-valent iron (ZVI) as a reductant and as a reactive material. Continued development of the technology over the years suggests that a robust understanding of PRB performance and the mechanisms involved is still lacking. Conflicting information in the scientific literature downplays the critical role of ZVI corrosion in the remediation of various organic and inorganic pollutants. Additionally, there is a lack of information on how different mechanisms act in tandem to affect ZVI-groundwater systems through time. In this review paper, we describe the underlying mechanisms of PRB performance and remove isolated misconceptions. We discuss the primary mechanisms of ZVI transformation and aging in PRBs and the role of iron corrosion products. We review numerous sites to reinforce our understanding of the interactions between groundwater contaminants and ZVI and the authigenic minerals that form within PRBs. Our findings show that ZVI corrosion products and mineral precipitates play critical roles in the long-term performance of PRBs by influencing the reactivity of ZVI. Pore occlusion by mineral precipitates occurs at the influent side of PRBs and is enhanced by dissolved oxygen and groundwater rich in dissolved solids and high alkalinity, which negatively impacts hydraulic conductivity, allowing contaminants to potentially bypass the treatment zone. Further development of site characterization tools and models is needed to support effective PRB designs for groundwater remediation.     

京津唐水资源规划决策支持系统研究

京津唐地区水资源规划是一个影响这一地区工农业发展和人民生活的多目标、大时空跨度的复杂问题.采用系统论的观点对这一问题进行了分析,并采用原型方法建立了京津唐水资源规划决策支持系统.系统由交互式对话子系统、数据库、模型库、方法库和知识库组成.模型库中装有系统动力学和多目标优化等模型;方法库中装有密切值法和两两比较法等,用于方案的排序;知识库中存贮着用于决策支持的知识.重点介绍京津唐水资源决策支持系统的逻辑和结构.     

柴油污染地下水修复生物反应墙中功能微生物数量及群落多样性

利用功能微生物、泥炭和含水层介质构建生物反应墙原位修复柴油污染地下水,系统经调试稳定后运行80 d,目标污染物去除率为83.60%~99.85%。运行期结束,采用荧光素-最大或然数和Biolog方法研究了生物墙内不同位置处功能微生物的数量及群落多样性。结果表明：墙体内各处均能保持较高的功能微生物数量,且微生物群落的物种数、丰富度、均一性、碳源利用性以及代谢特征均相似;但随着生物墙深度的增加,功能微生物比例有所下降,微生物群落略显丰富,但均一性略差,碳源利用倾向略微不同。生物反应墙原位修复地下水时,功能微生物能够长期保持较高的数量、较好的降解性能和稳定的群落多样性;但随着墙体深度的增加,营养结构发生了改变,导致微生物群落结构略显不同。     

土壤中可挥发性污染物清除的离心试验研究

土工离心模拟试验技术是研究环境岩土工程问题的有效手段。本文研究了非水相流体污染物在非饱和土中的迁移以及随后的抽气清除过程。 当离心机运行到要求的加速度时,汽油污染物从地下油罐中释放并在非饱和土中迁移一年,之后采用土壤通气法对污染土壤进行修复。对土壤取样分析,得到污染物在土体中的迁移规律和分布特征。试验结果表明,土壤通气法可以清除非饱和土体中的挥发性有机污染物,是一种有效的原位土壤修复技术。     

当地下水邂逅DNA:石油类有机污染及其生物降解

地下水科学与工程研究发展到今日,已经成为一门涉及多个领域的综合性学科。地下水污染的控制和修复研究更需要跨学科的技术和知识支持,而生物修复作为一种高效低耗修复的技术成为环境领域的研究热点。微生物因其自身特性及其对污染的降解主导特征对确定有机物污染场地的永续修复具有重要意义。简要地综述了地下水有机污染及其原位修复、有机污染物和地下环境微生物的交互作用,进一步聚焦生物降解机制、生物修复和细菌研究。在此基础上以某石油污染场地地下水为例,进行了地下水中分离微生物菌株及其降解特征的实验研究。结果表明:放线菌降解效果最好,细菌和真菌次之;两两组合降解效果好于单菌,表明存在协同作用;不同菌株混合降解率较低,表明具有拮抗作用。通过动力学实验得出对TPH的降解符合一级反应动力学方程及其降解速度和降解半衰期。就微生物对有机组分降解而言,烷烃和总石油烃降解规律相似;难降解组分降解率低,后期因烷烃转化使其浓度升高;苯浓度变化不大。微生物活性实验表明:活菌总数和脱氢酶活性与降解率呈正相关变化。运用生理生化及分子生物学方法鉴定得出了具体的菌种。     

基于信息熵技术对地下水观测网的层次分类--以河北平原地下水观测网为例

针对目前地下水观测网存在的层次不清问题，提出了基于信息熵技术的新的分类方法。列举了观测网层次混乱问题的表现、原因和可能造成的后果，提出地下水观测网具有层次性，而且这种层次性必须与地下水流动系统的层次性对应；认为地下水观测网就是一种信号通讯网，水位信号具有可传递性、差异性以及衰减性等特征，可以运用信息熵理论中的互信息概念定量刻画观测孔之间的信息联系，并以这种信息联系程度作为观测孔层次分类的主要依据；以河北平原地下水观测网为例，研究了区域尺度和局部尺度观测网的分类，结果表明信息熵方法可以很好地解决此类问题。     

污染地下水原位处理PRB技术研究进展

系统介绍了一种新型地下水污染治理技术,PRB（可渗透反应墙）技术。阐述了PRB的类型、活性材料的选取、反应机理、PRB的构建、应用实例以及存在问题等。并展望了其今后还需深入研究的方向。认为其是一种非常有发展前景的环境污染修复技术。这将为在我国开展该方法的研究和应用打下基础。