“5.12”地震灾区某固体废弃物填埋场岩体渗透特性评价

通过岩体结构调查、渗透张量计算和压水试验研究岩体渗透性能.结果发现,基岩裂隙潜水活跃带距地表70 m,是有毒元素向河流迁移的活跃通道,须采取河流改道、防渗等应急措施.地下水在岩体中的渗透以垂直方向为主,水平方向较小,总体上对工程有利.     

水泥土搅拌桩在垃圾填埋场地基处理中的应用

水泥土搅拌桩作为加固软土地基的一种成熟方法,适用于多种成因的饱和软粘土与粉土等地基。通过工程实例,介绍了水泥土搅拌桩在用于垃圾填埋场复合地基中,提高地基承载力与减少地基沉降量,保证垃圾堆体及地基整体稳定的作用,供类似工程参考。     

不同降雨模式下山谷型垃圾填埋场水分运移及其稳定性研究

近10年的运营经验表明,国内南方地区第1批建造的山谷型垃圾填埋场中的渗滤液水位一般较高。同时,现有研究表明,降雨入渗引起渗滤液水位过高是垃圾填埋场失稳的主要诱因之一。因此,研究强降雨条件下山谷型垃圾填埋场的水分运移规律及其稳定性,具有重要的现实意义。基于七子山填埋场浅层、中层和深层垃圾土的土-水特征曲线和Brooks-Corey公式,利用非线性拟合技术得到垃圾土的渗透性函数;运用饱和-非饱和渗流理论,对递减型、中心型、增强型和平均型4种降雨模式下七子山填埋场的水分运移进行了数值计算;利用极限平衡理论,对不同降雨模式下七子山填埋场的稳定性进行了分析。结果表明,降雨模式对山谷型垃圾填埋场内的水分运移规律和填埋场的稳定性有显著的影响,递减型降雨模式下填埋场内孔隙水压的变化最大,同时填埋场稳定系数也下降最为明显,为最不利降雨模式;经历7 d 746 mm的极端强降雨后,七子山填埋场具有极大的失稳隐患。     

垃圾卫生填埋中的一些岩土工程技术

垃圾卫生填埋是环境科学的重要研究内容,是一项综合性的研究课题。垃圾卫生填埋场高度和垃圾坝（或坑）深度的确定主要建立在岩土工程的稳定性理论基础上。在垃圾卫生填埋场中主要解决的防渗问题也是利用填埋场地质材料的渗透性质和现行的土工防渗技术,同时利用垃圾自身的物理力学特性解决填埋场排气等问题,而垃圾卫生填埋场的污水必须进行处理。从垃圾填埋场地质材料和垃圾自身的力学特性,结合某市垃圾卫生处理场实例对垃圾卫生填埋场中的一些岩土工程技术进行分析。     

不同岩性渗滤液污染场地中污染物衰减的模拟

选用细砂、粉砂、粘土和土壤为材料,通过4个系列的静态实验来研究不同岩性的垃圾渗滤液污染场地中pH、NO₃-N、NH₄-N、有机质及生物活性随时间的变化趋势及其相关性分析。实验结果表明,对于4种介质的pH而言,细砂>粉砂>粘土>土壤;对于NH₄-N、有机质和生物活性而言,均为土壤>粘土>粉砂>细砂;而对于NO₃-N而言,实验初期是土壤>粘土>粉砂>细砂,中期是细砂>粉砂>粘土>土壤,末期是土壤>细砂>粉砂>粘土。同时,综合4种介质中各指标的时间变化趋势利用SPSS进行相关性分析得到,在模拟垃圾渗滤液的污染场地中pH与有机质有很好的负相关性,相关系数为-0.649;有机质与生物活性有很好的正相关性,相关系数为0.640;NH₄-N与生物活性有很好的正相关性,相关系数为0.757。     

Statistical Assessment of Unidirectional Propagation of a Leachate Contamination Plume

The leachate produced by the Municipal Solid Waste Landfill of São Pedro da Aldeia (State of Rio de Janeiro, Brazil) flows almost entirely in one direction guided by a natural ditch in the bottom of a gentle valley. This landfill has been in operation with no concern to environmental protection, such as containment systems or leachate drainage and treatment. This inadequate operation causes severe damage to flora, wildlife and local farmers, due to continuous propagation of contaminants in the groundwater. Field and laboratory measurements of ionic concentrations of several contaminants found in the groundwater adjacent the landfill are presented and interpreted in this paper. Several farms are located adjacent to the landfill, comprising about 1,000 inhabitants that use the ground water for personal use and land farming activities. The main purpose of this paper is to assess the environmental hazard to the surrounding properties as the landfill is still in operation. This is accomplished by estimating the maximum distance travelled by the leachate plume based on the statistical interpretation of the measured ionic concentration of several contaminants found commonly in landfills. The main recommendation coming from the statistical assessment is that safe groundwater consumption should be limited to a minimum distance of 400 m from the contamination source, provided that the quality of ground water is continuously monitored while the MSW landfill is still in operation.     

竖向扩建填埋场变形离心模型试验研究

填埋场扩建是增大库容的重要手段,而其引起的沉降变形对填埋场及内部构筑物的稳定性有重大影响。针对扩建填埋场自重应力作用下的沉降变形问题,采用能够模拟我国固废工程特性的人工固废开展了平原型填埋场竖向扩建的离心模型试验。结果表明,堆体自重应力沉降随固废龄期增大而减小,最大沉降可达到堆体初始高度的20%。新老堆体界面不均匀沉降随老堆体龄期增大而减小,界面水平位移最大值出现在新堆体坡肩附近,且随坡比增加和龄期减小而增大。坡比越小,龄期和垃圾坝的作用越明显。垃圾坝对填埋堆体变形的影响随其相对高度减小而减弱。试验结果略大于常用的填埋场一维沉降计算结果,为填埋场增容及中间衬垫设计和稳定评估等提供了参考。     

上海某生活垃圾填埋场对浅层地下水水质的影响

垃圾填埋是目前处理城市生活垃圾普遍使用的方式,由此产生的垃圾渗滤液成为主要的地下水污染源.本文以上海市某生活垃圾填埋场作为研究对象,研究垃圾填埋对地下水的影响.通过监测该场地垃圾填埋前后2年内场区及周边地下水水质的变化情况,以垃圾填埋前调查区的地下水样品分析结果为本底值,采用本底法对地下水水质进行评价来判定地下水是否受到垃圾渗滤液的影响.评价结果显示,对于本研究的水质动态监测阶段,调查区内的浅层地下水水质暂未受到垃圾渗滤液的影响,个别监测井水质发生较大变化是由于填埋场施工建设过程中,破坏了监测井井盖及挖穿了井边含水层顶层.随着整个垃圾填埋场运行时间的延长,防渗漏措施的有效性以及垃圾渗滤液对周边地下水的影响还需要进一步研究.     

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.     

Apparent Formation Factor for Leachate-Saturated Waste and Sediments: Examples from the USA and China

The formation factor relates bulk resistivity to pore fluid resistivity in porous materials. Understanding the formation factor is essential in using electrical and electromagnetic methods to monitor leachate accumulations and movements both within and around landfills. Specifically, the formation factor allows leachate resistivity, the degree of saturation, and, possibly, even the hydraulic conductivity of the waste to be estimated from non-invasive surface measurements. In this study, apparent formation factors are computed for three landfills with different types of waste as well as sediments contaminated by landfill leachate. Resistivity soundings at the closed Mallard North landfill in suburban Chicago (Illinois, USA) mapped leachate surfaces that were confirmed by monitoring wells. The resistivity of leachate-saturated waste from resistivity sounding inversions was then divided by the leachate resistivity values measured in-situ to compute apparent formation factors (Fa) ranging from 1.6 to 4.9. A global Fa of 3.0±1.9 was computed for the entire monitored portion of this landfill At a nearby mixed laboratory waste landfill, a 2D inverted resistivity section was used to compute an Fa of 2.9. Finally, a distinctly different Fa value of 10.6±2.8 was computed for leachate-saturated retorted oil and organic compounds. The Fa for aquifers containing contaminated groundwater fall in the same range as aquifers with normal groundwater, 1.7-3.9. However, models from inverted sounding curves over these contaminated areas exhibit unusually low resistivity layers, which may be diagnostic of contamination.