Decision Analysis for Leachate Control at a Fractured Rock Landfill

The municipal landfill at the Complexe Environnemental de Saint-Michel (CESM) in Montreal, which is the third largest in North America, is located in a former quarry in fractured limestone. Impressive measures are taken to monitor and control biogas and leachate generated at the site. Leachate containment is presently performed with a pumping well completed within the waste. The efficiency of the well in controlling off-site leachate migration is questioned because field observations strongly suggest that the nearby former Francon quarry is diverting local ground water flow. To address this issue, four additional hydraulic control options are considered: (1) increased pumping at the existing waste well; (2) new pumping wells in the rock on the eastern limit of the site; (3) new injection wells in the rock on the eastern limit; and (4) combination of new injection wells at the same location and new water supply wells upgradient of the landfill. We evaluated the four hydraulic control options at the CESM using two coupled models: (1) a decision model based on an objective function weighting the risk, costs, and benefits of each option translated into dollar units; and (2) a numerical ground water flow model to represent the effect of operational conditions and ascertain success. Decision analysis offers a quantitative unbiased tool to evaluate the potential and relative cost of each option, but qualitative considerations and judgment still must be used for a complete evaluation. Our analysis confirms that scenario 4, which was the intuitively favored option, represents the best containment strategy.     

Spatiotemporal Variations in Microbial Communities in a Landfill Leachate Plume

We examined the spatiotemporal changes of microbial communities in relation to hydrochemistry variation over time and space in an aquifer polluted by landfill leachate (Banisveld, The Netherlands). Sampling in 1998, 1999, and 2004 at the same time of the year revealed that the center of the pollution plume was hydrochemically rather stable, but its upper fringe moved to the surface over time, especially at distances greater than 40 m away from the landfill. Complex and spatiotemporal heterogeneous bacterial and eukaryotic communities were resolved using denaturing gradient gel electrophoresis (DGGE) of 16S and 18S rRNA gene fragments. Large fluctuations were noted in the eukaryotic communities associated with strongly polluted and cleaner groundwater. The bacterial communities in strongly polluted samples were different from those in cleaner groundwater in 1998 and 1999, but no longer in 2004. The temporal variation in microbial communities was greater than the spatial variation: the 1998 bacteria communities in strongly polluted groundwater were more related to each other than to those recovered in 1999 and 2004. During the three sampling periods, the bacterial communities were more stable close to the landfill than at larger distances from the landfill. Overall, pollution appears to have only a minor influence on microbial communities. The considerable spatiotemporal variation in microbial community composition may contribute to better biodegradation of pollutants. Designing management strategies for natural attenuation of aquifer pollution will benefit from further long‐term, high‐density monitoring of changes in microbial communities, their diversity and physiological properties, in relation to changes in hydrochemistry.     

Landfill Leachate Treatment: A Case Study for Istanbul City

One of the most important problems arising from landfilling solid wastes is the leachate which contains high amount of pollution. Discharge of leachate without treatment causes negative effects on environmental and public health. In this study, parameters of chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen (NH₄‐N), and total phosphorus (TP) were examined in the samples taken from the influent and effluent of leachate treatment plant, where Odayeri landfill leachate is treated. Obtained results showed that the treatment plant, which consisted of preanoxic biological treatment system, ultrafiltration (UF) and nanofiltration (NF) units were operating with high efficiency. Among the examined parameters during study, COD, TN, NH₄‐N, and TP were found to be treated at the rate of 99, 94.5, 99, and 93.8%, respectively. Landfilling is increasing rapidly in the world and this consequently brings the need of leachate treatment facilities. Therefore, this study is considered to be a guide for construction and operation stages of proposed new treatment plants.     

基于PDA的地震灾情信息流动采集系统的设计与实现

针对地震现场工作需要, 提出了解决灾情快速采集上报问题的思路, 设计出基于3G网络和无线局域网络的灾情流动采集终端系统和后台服务系统, 利用QuickMap网络地图服务平台提供的GIS运行环境, 采用离线地图解决了在网络通讯困难时的地图下载问题。 经过实际野外测试, 效果良好, 能满足地震现场工作队员的工作需要。     

Utilizing Natural Liner Materials for Heavy Metal Removal in Simulated Landfill Conditions

Inorganic industrial waste landfills have the potential to contaminate subsurface groundwater supplies through migration of leachates down to the water table and into groundwater aquifers, despite the use of compacted low permeability clay or polyethene liners. This paper aims the removal of Cu²⁺ and Zn²⁺ in the leachate from an industrial waste landfill using natural materials (natural zeolite, expanded vermiculite, pumice, illite, kaolinite, and bentonite) as a liner material. Cu²⁺ and Zn²⁺ concentrations for all treatments decreased during the process. Of all the different natural materials, natural zeolite, expanded vermiculite and pumice, with bentonite, were effective in removing Cu²⁺ and Zn²⁺ present in the leachate. However, the use of illite and kaolinite with bentonite as liner materials could be of disadvantage in Cu²⁺ and Zn²⁺ removal from leachate. The adsorption kinetic models were also tested for the validity. The second order kinetics with the high correlation coefficients best described adsorption kinetic data.     

Pharmaceuticals and Other Organic Waste Water Contaminants Within a Leachate Plume Downgradient of a Municipal Landfill

Ground water samples collected from the Norman Landfill research site in central Oklahoma were analyzed as part of the U.S. Geological Survey (USGS) Toxic Substances Hydrology Program's national reconnaissance of pharmaceuticals and other organic waste water contaminants (OWCs) in ground water. Five sites, four of which are located downgradient of the landfill, were sampled in 2000 and analyzed for 76 OWCs using four research methods developed by the USGS. OWCs were detected in water samples from all of the sites sampled, with 22 of the 76 OWCs being detected at least once. Cholesterol (a plant and animal steroid), was detected at all five sites and was the only compound detected in a well upgradient of the landfill. N,N-diethyltoluamide (DEBT used in insect repellent) and tri(2-chloroethyl) phosphate (fire-retardant) were detected in water samples from all four sites located within the landfill-derived leachate plume. The sites closest to the landfill had more detections and greater concentrations of each of the detected compounds than sites located farther away. Detection of multiple OWCs occurred in the four sites located within the leachate plume, with a minimum of four and a maximum of 17 OWCs detected. Because the landfill was established in the 1920s and closed in 1985, many compounds detected in the leachate plume were likely disposed of decades ago. These results indicate the potential for long-term persistence and transport of some OWCs in ground water.     

Options for the Treatment and Management of Municipal Landfill Leachate: Common and Specific Issues

This paper aims to explore information from the literature for emphasizing the state‐of‐the art and progress in landfill leachate generation, fate and migration, and treatment. Leachate composition is discussed in terms of types of waste disposed and the processes occurring within landfill. The focus is also on potential pathways of environmental contamination by leachate, which may increase environmental and human health risk. The analysis addresses the opportunity and support for decision making concerning alternatives for leachate management and treatment. Advantages and limitations of treatment methods and processes are discussed considering leachate transfer, physico‐chemical methods, biodegradation, and combined methods.     

Nitrogen Removal from Landfill Leachate Using an Infiltration Bed Coupled with a Denitrification Barrier

Treatment of nitrogen in landfill leachate has received considerable attention recently because of the relatively low levels at which some nitrogen species (i.e., NH3) can be toxic to aquatic life forms. This study reports on the results of a three-year, pilot-scale field trial demonstrating the use of infiltration bed and nitrate barrier technology to achieve nitrogen removal in landfill leachate. The infiltration bed comprises an unsaturated sand layer overlying a saturated layer of waste cellulose solids (sawdust), which acts as a carbon source for heterotrophic denitrification. When loaded at a rate of 1 to 3 cm/day, the infiltration bed was successful at lowering leachate inorganic nitrogen (NH₄⁺+ NO₃^-) levels averaging 24.8 mg/L N by 89%, including 96% in the third year of operation. The surface water discharge criteria for un-ionized ammonia (NH3) were met on all occasions in the treated leachate during the second and third years of operation. Nitrogen attenuation is presumed to occur by a two-step process in which leachate NH₄⁺ is first oxidized to NO₃^- in the unsaturated sand layer and then is converted to nitrogen gas (N₂) by denitrification occurring in the underlying sawdust layer. Mass balance calculations suggest that the sawdust layer has sufficient carbon to allow denitrification to proceed for long periods (1.0 to 30 years) without replenishment. Because this technology is simple to construct and is relatively maintenance free, it should be attractive for use at smaller landfills where the installation of conventional treatment plants may not be feasible.     

Design of a Multi-Level Monitoring Well for Continuous Sample Collection

As part of a study of the flow dynamics and sampling environment around a high-capacity irrigation well, it was necessary to design and install a multi-level monitoring well network close to the production well. A requirement of the monitoring well network was the capability of continuous pumping over periods typical of those used during water sample collection. This was accomplished through the use of a control valve and air manifold system connected 10 a common gasoline engine-operated air compressor. The system provided adequate air pressure to operate 24 half-size bladder pumps to depths between 21 feet (6.4 m) and 56 feet (17.1 m) below the surface. Preliminary data collected from the monitoring well network indicate that the system will meet the requirements of the high-capacity well study.     

地震实时波形数据汇聚系统设计与实现

随着国家地震烈度速报与预警工程和地震信息化工程不断建设,地震台站数量激增,观测数据量呈指数型增长。为实现海量地震台站实时观测数据汇聚到国家中心,缩减数据汇集流程,本文开展了基于分布式技术（Hadoop技术框架）地震实时波形观测数据汇聚系统的研究,实现地震观测数据的云端采集,并以网络中断重连机制和实时流数据双链路接入机制保证数据的可靠传输,实现地震观测数据汇集的统一调度和高效管理。     

辽宁省地震应急值守和灾情收集系统设计

辽宁省地震应急值守和灾情收集系统能够解决"值班信息上报速度慢"、"人工上报信息错误率高"、"震区灾情收集效率低"等值班过程中存在的一系列问题.该系统是根据服务对象及业务流程等需求建立的"一体化应急综合值守自动响应体系",它将地震应急值守和灾情收集系统的值班值守工作纳入地震体系和政务系统建设当中,运用现代信息技术,建立健全值班值守管理、信息报送平台和快速、畅通的信息传递机制,同时提升了值班工作的信息化水平,保证了地震突发事件等重要信息的快速收集、编报、传递及处理,极大提高了地震应急综合处置能力、震区灾情收集能力和地震应急值守工作的效率.