竖井抽水下垃圾填埋场渗滤液运移规律研究

城市固废由于组成成分的多样性及分层填埋等原因,导致渗滤液运移存在明显的优先流及各向异性现象。在成都某填埋场开展多口竖井抽水及水位恢复试验,同时结合高密度电法技术(ERT)现场大尺度研究渗滤液分布及运移规律。多口竖井水位恢复试验显示填埋体内渗滤液运移具有明显的不均质性,表现为同一填埋场不同位置的竖井抽排性能差异较大,竖井周围垃圾渗透系数值分布范围为2.35×10-5~3.90×10-4 cm/s。竖井抽水下周围监测井的水位异常变化表明渗滤液补给存在明显优先流特征。ERT监测渗滤液抽水及回灌过程中堆体内电阻率变化,进一步揭示了现场渗流存在显著的各向异性和优先流特征,主要渗流路径与水平向呈0~30°。     

Organic indicators of groundwater pollution by a sanitary landfill

The organic composition of leachate from the Barcelona sanitary landfill is described. According to the low degree of stabilization of the disposed garbage the acid fraction accounts for 80–90% of the total organic extract. More than 50 individual organic components have been identified, indicating catabolic degradation of lipids (e.g. C₄–C₁₁ carboxylic acids), proteins (e.g. indole derivatives) and lignins (e.g. p-hydroxyphenyl derivatives) or simply compounds originally present in the refuse that have been washed out by percolating waters (nicotine, caffeine, phthalates).To obtain a monitoring system for the groundwater pollution originated by this landfill leachate, an analytical method is proposed based on the GC-ECD fingerprinting of groundwater acidic extracts after derivatization with PFB bromide. The chromatogram contains carboxylic and phenolic components and the profiles exhibited by waters from several test wells in the downstream edge of the landfill were indicative of the suspected leachate pollution.     

Effects on groundwater flow and groundwater quality of a waste disposal site in Noordwijk,The Netherlands

The effects of a waste disposal site in Noordwijk on the groundwater flow and groundwater quality were investigated. Special attention is given to the extension of pollutants in the aquifer. Several boreholes were made and groundwater has been sampled and analysed. Measurement of electrical resistivity and an electromagnetical investigation were carried out. Already beneath the landfill pollution was found on the fresh- salt water boundary at about 40 meters -l.s. A very large vertical flow component due to density flow could be calculated. Local flow patterns indicate an all-sided migration of pollutants. Short-circuit flow caused by the drilling of boreholes can effect the quality of groundwater seriously.     

岩土工程技术在现代卫生填埋场设计中的应用

卫生填埋将成为我国城市垃圾处理的发展方向,结合现行国家规范,针对目前卫生填埋场的研究及设计中存在的主要问题与不足进行讨论,并探讨岩土工程在现代卫生填埋场设计中的应用问题。     

浅谈生活垃圾卫生填埋场选址中应注意几个问题

生活垃圾卫生填埋场多处于农村或城乡结合部,其选址涉及多方面因素,不仅要分析其是否符合相关政策、规划、规范、标准等要求,而且还要紧密结合所选场址各方面特征因素,全面分析其可能存在的影响,尤其应关注对农村、农业和农民的影响,并提出解决办法。本文结合环评实践,阐述选址中应该注意几个问题。     

Landfill Site Selection: A Microcomputer Expert System

Sanitary landfills are common facilities for waste disposal. The process of designating a location as a landfill requires extensive studies of biogeochemical and hydrologic characteristics of all potential sites. This process demands a considerable amount of empirical inputs, expert opinions, and heuristic rules. A site selection process can be modeled only by incorporating the available empirical and expert rules into our decision making process. This task can be accomplished in the framework of knowledge-based expert systems. A prototype expert system for site selection is presented. The rules are based on U.S. EPA documents for ranking of uncontrolled hazardous waste sites for remedial actions. They include rules concerning ground water routes, local climate, waste characteristics, planned features of the proposed landfill facility, and targets at risk. The above model is programmed with the aid of Insight 2+, which is a microcomputer shell program.     

垃圾土沉降的Logistic模型应用研究

垃圾土的沉降是卫生填埋场沉降机理设计时需考虑的一个重要因素。通过对垃圾土沉降的分析,指出垃圾土的沉降机理相当复杂,与土的沉降机理不尽相同。分析了现有垃圾土沉降模型计算存在的问题。采用使观测值和预测值残差平方和达到最小的方法对Logistic模型求取参数,并应用于香港Sai Tso Wan垃圾填埋场及巴西Bandeirantes填埋场封场期后的沉降预测研究。结果表明,只要选取合适的参数,可以克服现有沉降计算模型的缺陷,大幅度提高垃圾土封场期后沉降值的预测精度。     

某填埋场垃圾堆体边坡失稳过程监测与反分析

某填埋场是国内首批在场底铺设复合衬垫系统的大型卫生填埋场,该场垃圾坝前堆体边坡于2008年6月连续强降雨期间发生失稳事件。介绍该堆体边坡失稳过程的现场监测结果,包括坡面水平位移、深层侧向位移和渗滤液水位。基于监测数据,开展堆体边坡稳定性反分析工作,探讨复合衬垫系统界面抗剪强度取值方法,提出抽排竖井迫降水位、铺膜防渗等应急抢险措施。现场监测和理论分析结果表明:堆体边坡中高渗滤液水位是导致其失稳的关键因素,堆体边坡水平位移速率和渗滤液水位高度呈明显正相关关系;该堆体边坡失稳模式是沿场底复合衬垫系统中软弱界面的深层滑移;斜坡场底上复合衬垫系统在滑移过程中发生位移-软化效应,其界面强度介于峰值强度和残余强度之间;抽排竖井迫降水位是最直接、有效的应急抢险措施。     

浅析生活垃圾卫生填埋场运行和防治

随着我国人口的不断增长,每天都有很多的生活垃圾产生。为此,我国有很多的卫生填埋场在不间断地运行,这些卫生填埋场造成了很严重的污染问题。本文主要阐述了生活垃圾卫生填埋场的运行和防治问题。     

A reactor model for pulsed pumping groundwater remediation

A hybrid in situ bioremediation/pulsed pumping strategy has been developed to cost effectively remediate a carbon tetrachloride plume in Schoolcraft, Michigan. The pulsed pumping system uses a line of alternating injection and extraction wells perpendicular to the direction of natural groundwater flow. The wells pump periodically to clean the recirculation zone between adjacent wells. During the pump-off phase, natural groundwater flow brings new contaminant into the recirculation zone. The wells are pumped again prior to breakthrough of contaminant from the recirculation zone. A computationally efficient reactor model has been developed, which conceptually divides the aquifer into injection, extraction, and recirculation zones, which are represented by a network of chemical reactors. Solute concentration histories from three-dimensional finite difference simulations and from field data confirm the reactor model predictions. The reactor model is used to investigate the optimal well configuration, pumping rate, and pumping schedule for achieving maximum pollutant degradation.     

The effects of a hazardous and a domestic waste landfill on the trace organic quality of chalk groundwater at a site in East Anglia

As part of a research project to assess the effects of landfill leachates on groundwater quality thirteen boreholes within, around and down groundwater gradient from two adjacent domestic and hazardous wastes sites were sampled for trace organic quality.Results so far show that significant inorganic and gross organic (TOC) groundwater contamination does not occur more than a few metres from the landfill boundaries. Trace organic analyses indicate that the mineral oils, phenolic wastes and chlorinated solvents, known to have been tipped into the hazardous waste landfill, have now reached the water table, although only at low concentrations.     

固体废弃物填埋场建设中的环境岩土工程问题

人与环境的和谐共处是当今社会可持续发展的重要内容,面对城市固体废弃物激增所带来的人与环境之间的各种问题,卫生填埋法作为最广泛也是最彻底的固体废弃物处理方法得到了越来越多的关注和研究.环境岩土工程是岩土工程与环境科学密切结合的一门新学科,它主要应用岩土工程的观点、技术和方法,为治理和保护环境服务.卫生填埋场的建设与环境岩土工程领域内的诸多方面密切相关.针对卫生填埋场的建设中涉及到的环境岩土工程问题,在依据已有资料概括介绍国内外相关发展现状的同时,结合西安地区的特点,在填埋场场址和类型选择、废弃物工程性质指标、填埋场防渗处理、填埋场沉降计算和边坡稳定这五个方面对西安地区城市固体废弃物卫生填埋场建设中的环境岩土工程问题进行了论述,并提出了相应建议,展望了研究方向.     

云南省新平县生活垃圾卫生填埋场工程设计

介绍了云南新平县城市生活垃圾卫生填埋场工程概况及主要设计内容。在设计中针对当地气候条件和地质特征,因地制宜,优化设计,旨在提高工程经济性及实用性。其中填埋工艺采用了"HDPE+GCL"水平单层复合防渗系统,渗滤液采用了过滤预处理+两级碟管反渗透(DTRO)组合处理工艺。     

松散承压含水层地区深基坑降水三维渗流与地面沉降耦合模型

以上海环球金融中心基坑降水为例,根据基坑降水过程中有效应力和孔隙水压力的转化关系,建立了基坑降水与地面沉降的耦合模型,并采用有限差分数值模拟方法,模拟了在多层含水层复合存在、含水层最深底板埋深达145 m、基坑周围挡水连续墙埋深达34 m、抽水井埋深达55 m、抽水井过滤器埋深为34～55 m,单井抽水量为1420 m3/d的8口抽水井联合降水情况下,基坑中心下伏第Ⅰ承压含水层上部降压段水位降至埋深26 m时的地下水复杂流动状态及其地面沉降特征。经后续工程验证,该结果正确、可靠,该理论用于模拟预测此类地区深基坑降水引起的地下水流场变化及其地面沉降具有较高的可信度。     

垃圾填埋场沉降变形条件下气-水-固耦合动力学模型研究

基于多孔介质流气–水–固耦合和微生物降解理论,建立描述这一复杂动力学行为的二维气–水–固耦合数学模型,并给出耦合模型的数值格式。通过数值仿真实现垃圾填埋体的变形沉降及气体产生和迁移演化过程的可视化,得到气体压力及产气量随填埋年份的变化规律。数值计算结果表明:填埋体内总应力及孔隙度的改变与垃圾降解变化规律一致;抽气过程使场内气体压力得到释放;由于沉降作用填埋场内水相饱和度有增大的趋势,其中底部变化较顶部明显;此外,气井产量的变化与气体迁移单相模型的计算结果基本吻合,验证耦合模型的可靠性,其研究成果为垃圾填埋场沉降控制与气体资源化利用提供技术支持和理论依据。     

Überwachung der Auswirkungen von Flussaufweitungen auf das Grundwasser mittels Radon

The restoration of the perialpine river Töss in a floodplain of northern Switzerland (Linsental) included the removal of bank reinforcements and tracer studies in the river and in oberservation wells of the adjacent alluvial groundwater. The river water is continuously recharging the aquifer system and the groundwater is used extensively as drinking water. Radon activity concentrations of freshly infiltrated groundwater are interpreted as radon groundwater age between the river and a well. A first flood after the restoration operations resulted in a widening of the river bed and in a reduction of the flow distance to the wells. Sixteen days after a second flood, the results of radon measurements were compared with those from before the restoration. The radon age of the groundwater between the river and the wells decreased, probably as a result of the reduction of the flow distances. Concentrations of autochthonous and coliform bacteria increased after the restoration operation and even more one day after the first flood. Thus the findings on the bacteria corroborate the interpretation of the radon concentrations. The restoration has not yet reduced the quality of the groundwater, which is pumped for drinking water. The study is contributing to the solution of land-use conflicts between river restoration and the supply of drinking water from the alluvial groundwater.     

Simulation modelling for groundwater safety in an overexploitation situation: the Maggiore Valley context (Piedmont,Italy)

The Maggiore Valley well field plays a fundamental role in supplying drinking water to a large territory of the Piedmont (north-western Italy). However, an increasing demand for water has led to the overexploitation of the groundwater resources. This situation has caused a progressive drawdown of the piezometric level (locally, up to 0.8 m/year), a spatial reduction in the artesian zone, localised land subsidence and damage to wells. The main purpose of this study was the development of a groundwater flow model of the area for analysing the aquifer response to various pumping strategies. Initially, the groundwater flow simulation (achieved by the application of the MODFLOW code) was calibrated satisfactorily. Then, the groundwater response to four scenarios was simulated to explore the best option to mitigate the problem. In three of the scenarios, a withdrawal reduction of 110 l/s was simulated, whilst considering various relocation options for extraction within the well field. The fourth scenario simulated a withdrawal reduction of 150 l/s; this option also assumed a supplementary water supply from the Monferrato Aqueduct, located north of the study area. All the simulations provided an increase in the piezometric level; in some instances, up to 30 m. Based on these simulations, the most promising management strategy for the Maggiore Valley well field would seem to be the option using a supplementary feed from the Monferrato Aqueduct. In this instance, the predicted piezometric level rise would be up to 25 m; this option also precludes the need for drilling additional wells.     

Interrelation of wastewater and groundwater management in the city of Bijeljina in Bosnia

The city of Bijeljina lies on alluvial deposits of the river Drina, which provide groundwater storage of great capacity with good hydraulic properties. Groundwater is abstracted by wells which are located in a field close to the city, and used for public water supply. In the summer of 1993, large numbers of coliform bacteria were found repeatedly in two of the wells. A study was initiated with the main objective of providing a short-term solution to the problem, as well as some guidelines for the long-term groundwater management strategy. A regional groundwater flow model was developed, calibrated and verified. In situ tracer experiments were used to improve the reliability of particle tracking computations. The results were used to prove that the sources of pollution were domestic septic tanks upstream of the well field. The problem was temporarily solved by closure of five wells capturing polluted water and opening some new wells in the less affected zone. The particle tracking results show why this strategy works, but also show that it is only a temporary solution. As a long-term solution, a sewerage system and network of monitoring wells were proposed. The sewerage system has been constructed recently. The role of monitoring is to check if bacterial pollution has ceased following the construction of the sewerage system, as well as to detect other types of pollutants. Groundwater levels have been monitored for one year already, so the data for model re-calibration has been collected. The re-calibrated model can be used for more accurate delineation of protective zones, prediction of the risks related to other pollutants, analysis of the possibility to reactivate the closed wells, etc. As the major objective in long-term water resources management, it is proposed that an integrated approach should be adopted, with simultaneous management of water supply, wastewater and solid waste.     

Assessing And Managing Risk In The Public Sector: An Urban Hazardous Waste Landfill

ABSTRACT: This paper examines how risk was assessed and managed at the Adams Center Hazardous Waste Landfill in Fort Wayne, Indiana. The landfill is one of 21. federally licensed hazardous waste landfills in the United States. Like a majority of these landfills, Adams Center evolved out of an existing sanitary, nonhazardous landfill. The process used to transform the Adams Center landfill was deficient in considering technical and cultural factors in risk assessment and in providing a forum where these differences could be addressed and where issues of risk mitigation and compensation could be discussed. The landfill operators are facing strong opposition in their attempt to expand. The author suggests alternative models for assessing and managing the risks of hazardous waste that would more broadly represent affected interests in decision making and produce a more comprehensive definition of risk and a more integral focus on risk mitigation and compensation.     

垃圾填埋场的污染与防治

填埋场垃圾是放错了地方的资源,如果处理不当,不仅白白浪费可利用资源,还会造成严重的二次污染,失去卫生填埋的最初意义。介绍了垃圾卫生填埋场中常见的三种二次污染：水污染、空气污染和土壤污染。并从这三个方面入手提出了防止二次污染的的一系列建议和措施,以及相应的资源化处理。详细介绍了防止垃圾渗滤液渗漏的方法,垃圾填埋场防渗层的设计和材料选取、渗滤液的收集等,提出了国际上垃圾处理技术的今后发展的新趋势。