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1.
The behavior of the Gimpo #2 landfill, which is an active landfill and the largest in Korea, is analyzed using field measurement data obtained from various field instruments installed within the landfill. The data included in this analysis are the leachate head within the landfill, waste load data using soil pressure plate and settlement data from settlement plate on the surface of the waste of each stage fill including the settlement of the soft foundation clay soil. Landfill blocks are selected both near the embankment and in the center area of the landfill. The analysis of the field-monitored data showed that the leachate head increase was negligible near the embankment. It was significant in the central block as the waste loads increase and reached 15 m at the fourth stage of waste disposal. The reason that the leachate head is higher in the central block than near the embankment is due to the long drainage path and the loss of gradient of drain pipes. The range of unit weight of the waste converted from the measurement data of earth pressure cell was 0.91–1.24 t/m3 and the average value was 1.05 t/m3. The values reflect well the waste compositions recently buried in GML #2, since from 1998 the waste disposed in GML #2 did not contain food waste. The magnitude of final settlements that occurred in each stage loading of 5 m thickness in the peripheral block was very close to 120 cm. The settlement rate of the waste by dividing the thickness of waste was 24 %. This rate can be divided into 10 % by waste loading and 14 % by waste decomposition. The delay of settlements is recognized in each waste layer for second and third loading in the central block due to the accumulation of leachate within the landfill.  相似文献   

2.
居朦萌  施建勇 《岩土力学》2016,37(Z1):381-390
为了研究渗滤液水位以下产气对孔隙压力的影响,从孔隙气在渗滤液水位以下特定的流动状态出发,采用峰值产气模型,结合了达西定律、理想气体状态方程和多孔介质流体动力学理论,建立了渗滤液水位以下考虑产气作用的气液迁移模型。运用差分法对产气引起的气液迁移问题进行了数值求解。计算结果表明,渗滤液水位以下垃圾体的产气对孔隙压力的影响主要有渗滤液渗流引起的附加孔隙压力和水位升高引起的附加孔隙压力,按孔隙气所处阶段的不同可以分为孔隙气被封闭时孔压积聚阶段、孔隙气突破孔隙水封闭时的孔压急剧消散阶段以及由对流作用控制的气液运移阶段;高产气速率、高渗滤液水位和低渗透系数都会使得垃圾体内产生较高的孔隙压力;降低填埋场内渗滤液水位是减小产气对孔隙压力影响的有效措施。  相似文献   

3.
Annual variation in the amount and composition of waste deposited in the Gimpo #2 landfill, the largest landfill around Seoul, Korea, is reviewed, and the stability of the same landfill is analyzed during waste disposal. For the stability analysis, three empirical stability prediction methods, i.e., linear stability, displacement velocity, and curve stability methods, are used to analyze field-measured settlement and horizontal displacement data. The analysis indicated that national waste management policy has greatly influenced the annual variation in the amount and composition of waste deposited in the landfill. Continuous measurement of geotechnical data and the use of stability analysis based on these data are necessary for landfills on seashore clay foundation. Stability of the landfill must be examined with various methods to ensure accurate determination of its stability.  相似文献   

4.
为了加速填埋场降解的稳定化,渗滤液回灌常被应用在工程实践中。使用竖井进行回灌是较为有效的方式之一。伴随着液体的注入,由于对流的产生,垃圾土温度势必会发生改变。基于无锡填埋场注水试验,对该现场试验过程中垃圾土温度的改变进行模拟。为此,建立了考虑渗透系数和孔隙率随深度变化的渗流模型,以及考虑渗流影响的热对流-热传导模型,并利用数值计算方法进行求解。在对比计算值和试验值之后,发现所建立的模型能较好地模拟注水期间渗滤液水位和垃圾土温度的变化规律。结果表明：在离注水井超过6 m处的位置,显现的液位相对滞后,至少滞后0.15 d,而且距离越远滞后的时间越长;在液位以下,注水井周围的垃圾土温度均低于初始温度。但是在径向上远离注水井3.6 m之外的垃圾土温度并不是全低于初始温度,在新老垃圾土交界处之上2 m范围内,会出现温度高于初始温度的现象,温度差可达3 ℃;新填垃圾土的已降解时长对单井注水工况下温度分布的影响较为显著。  相似文献   

5.
Modern waste management tends towards greater sustainability in landfilling, with the implementation of strategies such as the pretreatment of solid waste. This work assesses the behaviour of rejects from a refining stage of mechanically biologically treated municipal solid waste at the landfill. The main results of 18 months’ monitoring of an experimental pilot cell with waste from a full-scale plant are presented. This first stage is expected to be the most problematic period for this type of waste. The evolution of the temperature and the composition of leachate and gas at various points within the cell are included. During the first weeks, pollutant concentrations in the leachate exceeded the reference ranges in the literature, coinciding with a rapid onset of methanogenic conditions. However, there was a quick wash, reducing concentrations to below one-third of the initial values before the first year. pH values influenced concentrations of some pollutants such as copper. These results indicate that, right from the beginning of disposal, such facilities should be prepared to treat a high pollution load in the leachate and install the gas emissions control elements due to the rapid onset of methanogenesis.  相似文献   

6.
The current solid waste disposal site in the Mamak district of Ankara is being engulfed by the growing city. All varieties of solid wastes, including medical wastes, are stored at the present site in an irregular manner. Topographical and geological conditions at Mamak waste site are favorable for constructing a sanitary landfill. Located at the edge of a topographical depression, the site is underlain by the natural hydraulic barriers such as clay and metagreywacke. The terrestrial clay has a permeability of 10−7 to 10−8 cm/s and low to moderate values of CEC. The proposed sanitary landfill to replace the present solid waste site has a capacity of storing solid waste over 50 years. The details of base liner, final cover, toe embankment, and drainage of leachate and gas are presented in the paper.  相似文献   

7.
A bioreactor landfill is operated to enhance refuse decomposition, gas production, and waste stabilization. Some of the potential advantages of bioreactor include rapid stabilization of waste, increased landfill gas generation, gain in landfill space, enhanced leachate treatment, and reduced post closure maintenance period. Due to the accelerated decomposition and settlement of solid waste, bioreactor landfills are gaining popularity as an alternative to the conventional Subtitle D landfills. However, the addition of leachate to accelerate the decomposition changes the physical and engineering characteristic of waste and therefore affects the geotechnical characteristics of waste mass. The changes in the physical and mechanical characteristics of solid waste with time and decomposition are expected to affect the shear strength of waste mass. The objective of this paper is to analyze the stability of solid waste slopes within the bioreactor landfills, as a function of time and decomposition. The finite element program PLAXIS is used for numerical modeling of bioreactor landfills. Stability analysis of bioreactor landfills was also performed using limit equilibrium program STABL. Finally the results from finite element program PLAXIS and limit equilibrium program STABL are compared. GSTABL predicted a factor of safety of more than 1 in all the cases analyzed, whereas PLAXIS predicted a factor of safety of less than 1 at advanced stages for a slope of 2:1. However, the interface failures between solid waste and landfill liners have not been considered in this paper.  相似文献   

8.
 This paper presents the results of field tests of hydrologic parameters in a landfill and the results of numerical simulation to find the efficiency of the pumping method to reduce leachate levels in the landfill. The field hydraulic conductivity and storativity of waste and buried cover soils in the landfill are measured by pumping and slug tests. The hydrologic condition inside the landfill is first calibrated using the drawdown-time curve obtained from the pumping test, and the flow behavior of leachate during pumping in the landfill, when various layers of waste and buried cover soil exist, is analyzed through three-dimensional numerical simulation of flow. The results of the field investigation show that the buried cover soil of low hydraulic conductivity forms an impermeable layer preventing the downward flow of leachate and upward flow of landfill gas. The hydraulic conductivities of the pumping test and slug tests were quite close on the same order of magnitude. It was also possible to match the drawdown-time data of the field tests with those of the model using input data close to the hydrologic property obtained from the field tests. The numerical flow analysis showed that pumping was possible up to 120 tons/day for a single well without a drain, while the pumping rate could be increased to 300 tons/day for the same well with the drain. From the vertical section of the flow vector with a horizontal drain, the barrier role of buried cover soil is identified, which was proposed by examining the water contents of the disposed cover soil and waste in the field. Received: 15 May 1998 · Accepted: 4 January 1999  相似文献   

9.
Commercially available hydraulic total overburden pressure cells were installed in the sand drainage layer of a municipal solid waste landfill and monitored for a period of 3,110 days. Both overburden pressure and temperature were measured in the landfill as it was filled with compacted waste. Topographic surveys of the landfill were periodically conducted to measure the height of waste above the pressure cells and to determine the landfill volume for indirect unit weight estimation. The average ratio of measured to theoretically-predicted overburden pressure was 0.6, indicating that on average the pressure cells underestimated the load. The overburden pressure measured near the toe of the landfill was greater than that predicted by the unit weight of landfilled material, while most of the overburden pressure measurements further inside the landfill were less than predicted. Several possible causes for this phenomenon are discussed, including the uneven distribution of forces resulting from the heterogeneous nature of the waste and cover soil. The earth pressure cells were capable of detecting the placement of individual waste lifts.  相似文献   

10.
During leachate recirculation, a bioreactor landfill will experience more rapid and complete settlement, which is mainly attributed to the weight of municipal solid waste (MSW) and its biodegradation. The settlement of MSW may cause the decrease of void ratio of MSW, which will influence the permeability of MSW and the leachate quantity that can be held in bioreactor landfills. In this study, a new one-dimensional model of leachate recirculation using infiltration pond is developed. The new method is not only capable of describing leachate flow considering the effect of MSW settlement, but also accounting separately leachate flow in saturated and unsaturated zones. Moreover, the effects of operating parameters are evaluated with a parametric study. The analyzing results show that the influence depth of leachate recirculation considering the effect of MSW settlement is smaller than the value without considering the effect. The influence depth and leachate recirculation volume increase with the increase of infiltration pond pressure head and MSW void ratio. This indicates that the field compaction of MSW has a great influence on the leachate recirculation.  相似文献   

11.
Containment landfills: the myth of sustainability   总被引：5，自引：0，他引：5  
A. Allen   《Engineering Geology》2001,60(1-4):3-19
A number of major problems associated with the containment approach to landfill management are highlighted. The fundamental flaw in the strategy is that dry entombment of waste inhibits its degradation, so prolonging the activity of the waste and delaying, possibly for several decades, its stabilisation to an inert state. This, coupled with uncertainties as to the long-term durability of synthetic lining systems, increases the potential, for liner failure at some stage in the future whilst the waste is still active, leading to groundwater pollution by landfill leachate. Clay liners also pose problems as the smectite components of bentonite liners are subject to chemical interaction with landfill leachate, leading to a reduction in their swelling capacity and increase in hydraulic conductivity. Thus, their ability to perform a containment role diminishes with time. More critically, if diffusion rather than advection is the dominant contaminant migration mechanism, then no liner will be completely impermeable to pollutants and the containment strategy becomes untenable.

There are other less obvious problems with the containment strategy. One is the tendency to place total reliance on artificial lining systems and pay little attention to local geological/hydrogeological conditions during selection of landfill sites. Based on the attitude that any site can be engineered for landfilling and that complete protection of groundwater can be effected by lining systems, negative geological characteristics of sites are being ignored. Furthermore, excessive costs in construction and operation of containment landfills necessitate that they are large scale operations (superdumps), with associated transfer facilities and transport costs, all of which add to overall waste management costs. Taken together with unpredictable post-closure maintenance and monitoring costs, possibly over several decades, the economics of the containment strategy becomes unsustainable. Such a high-cost, high-technology approach to landfill leachate management is generally beyond the financial and technological resources of the less wealthy nations, and places severe burdens on their economies. For instance, in third world countries with limited water resources, the need to preserve groundwater quality is paramount, so expensive containment strategies are adopted in the belief that they offer greatest protection to groundwater. A final indictment of the containment strategy is that in delaying degradation of waste, the present generations waste problems will be left for future generations to deal with.

More cost-effective landfill management strategies take advantage of the natural hydrogeological characteristics and attenuation properties of the subsurface. The ‘dilute and disperse’ strategy employs the natural sorption and ion exchange properties of clay minerals, and it has been shown that in appropriate situations it is effective in attenuating landfill leachate and preventing pollution of water resources. Operated at sites with thick clay overburden sequences, using a permeable cap to maximise rainfall infiltration and a leachate collection system to control leachate migration, ‘dilute and disperse’ is a viable leachate management strategy. Hydraulic traps are relatively common hydrogeological situations where groundwater flow is towards the landfill, so effectively suppressing outwards advective flow of leachate. This approach is also best employed with a clay liner, taking advantage of the attenuation properties of clays to combat diffusive flow of contaminants. These strategies are likely to guarantee greater protection of groundwater in the long term.  相似文献   


12.
Landfill site selection and landfill liner design for Ankara, Turkey   总被引：2，自引：1，他引：1  
Considering the high population growth rate of Ankara, it is inevitable that landfill(s) will be required in the area in the near future to sustain the sanitary waste disposal needs of the city. The main scope of this study is to select alternative landfill sites for Ankara based on the growing trends of Ankara toward the northwest, particularly toward the Sincan municipality, and to eventually select the best alternative through utilizing multi-criteria decision making. Landfill site selection was carried out utilizing Geographic Information System (GIS) and Multi-Criteria Decision Analysis. A number of criteria, namely, settlement, slope, proximity to roads, geology, availability and proximity of landfill containment material (i.e., clay for composite lining system), suitability for agriculture, erosion, vegetation cover and lineament system were gathered in a GIS environment. Each criterion was assigned a weight value by applying the Pairwise Comparison Method and the Analytical Hierarchy Method. In order to choose the best alternative, the Technique for Order Preference by Similarity to the Ideal Solution, which is regarded as an ideal point method, was applied and a landfill site was selected. The geotechnical properties of the so-called “Ankara clay” that shows widespread distribution in Ankara were reviewed and assessed for its suitability as a compacted clay liner.  相似文献   

13.
An extensive use of solid-waste landfills for disposal of municipal and industrial wastes have prompted increased attention to groundwater pollution caused by leachate generated in such landfills. The potential for groundwater contamination by leachate has necessitated engineering designs for landfills. The quantity of leachate generated from the solid waste and the movement of water through the solid waste depends on water input and the solid-waste characteristics. This paper dealt with the experimental investigations using the laboratory solid-waste leaching column to estimate the total leachate volume/leachate flow for unsaturated and saturated conditions. The hydraulic properties of the solid waste like initial moisture content, field capacity, permanent wilting point, saturation moisture content, effective void ratio, saturation hydraulic conductivity and saturation suction pressure were determined from the small-scale laboratory experiments, which are the input for analytical model study of leachate flow/total leachate volume for both unsaturated and saturated conditions. The result of analytical model study was compared with the results of experimental investigations. Comparisons of measured and computed total leachate volume/leachate flow using Darcy’s law showed reasonable agreement.  相似文献   

14.
The grid-net electrical conductivity measurement system for detecting exact locations of landfill leachate intrusion in the subsurface was developed in this study. Laboratory and pilot-scale field model tests were performed to evaluate the direct application of a grid-net electrical conductivity measurement system for the detection of landfill leachate. A significant increase in electrical conductivity of soil was observed by adding landfill leachate. This can be explained as an increase in electrical conductivity of pore fluid due to an increase in leachate constituents as charge carriers. In pilot-scale field model tests, leachate intrusion locations were accurately identified at the initial stage of landfill leachate release by the grid-net electrical conductivity measurement system. The electrical conductivity of the subsurface before leachate injection lay within a small range of 24.8–43.0 S/cm. The electrical conductivity values in detected points were approximately ten times more than the conductivity values of the subsurface without landfill leachate intrusion. The results in this study indicate that the grid-net electrical conductivity measurement method has a possible application for detecting locations of landfill leachate intrusion into the subsurface at the initial stage, and thus has great potential in monitoring leachate leakage at waste landfills.  相似文献   

15.
Groundwater is inherently susceptible to contamination from anthropogenic activities and remediation is very difficult and expensive. Prevention of contamination is hence critical in effective groundwater management. In this paper an attempt has been made to assess aquifer vulnerability at the Russeifa solid waste landfill. This disposal site is placed at the most important aquifer in Jordan, which is known as Amman-Wadi Sir (B2/A7). The daily-generated leachate within the landfill is about 160 m3/day and there is no system for collecting and treating this leachate. Therefore, the leachate infiltrates to groundwater and degrades the quality of the groundwater. The area is strongly vulnerable to pollution due to the presence of intensive agricultural activity, the solid waste disposal site and industries. Increasing groundwater demand makes the protection of the aquifer from pollution crucial. Physical and hydrogeological characteristics make the aquifer susceptible to pollution. The vulnerability of groundwater to contamination in the study area was quantified using the DRASTIC model. The DRASTIC model uses the following seven parameters: depth to water, recharge, aquifer media, soil media, topography, impact on vadose zone and hydraulic conductivity. The water level data were measured in the observation wells within the disposal site. The recharge is derived based on precipitation, land use and soil characteristics. The aquifer media was obtained from a geological map of the area. The topography is obtained from the Natural Resources Authority of Jordan, 1:50,000 scale topographic map. The impact on the vadose zone is defined by the soil permeability and depth to water. The hydraulic conductivity was obtained from the field pumping tests. The calculated DRASTIC index number indicates a moderate pollution potential for the study area.  相似文献   

16.
设计软黏土中单桩模型箱试验,模拟了桩周土逐级加荷沉降,通过量测超孔隙水压力、土体沉降及桩身轴力变化,分析了软黏土进入次固结阶段时,桩侧负摩阻力及桩身中性点位置变化情况。研究表明,在次固结阶段桩周土所产生的沉降对桩侧负摩阻力仍具有一定影响,沿桩身呈先增大后减小的趋势;当桩周土所施荷载等级达到一定程度时,桩身中性点位置将随着桩周土次固结时间的增长而逐渐上移。次固结阶段产生的沉降量与土体上所施加的荷载等级有关,随着桩周土荷载等级的增大,次固结阶段产生的沉降所占总沉降的比例逐渐减小,其蠕变效应逐渐减弱。  相似文献   

17.
Magnetic properties and heavy metal content of landfill leachate sludge samples from two municipal solid waste disposal sites near Bandung, West Java, Indonesia, and their correlation with heavy metals are studied in the present work. Leachate was found to be sufficiently magnetic with mass-specific magnetic susceptibility that varies from 64.8 to 349.0 × 10−8 m3 kg−1. It is, however, less magnetic than the soils around the landfill sites. The magnetic minerals are predominantly pseudo-single domain and multidomain magnetite. Leachate samples from the older but inactive disposal site, Jelekong, are found to be more magnetic than that from Sarimukti, the younger and active site. The enhancement of leachate due to the soil-derived ferrimagnetic particles is possibly the same for both Sarimukti and Jelekong. The fact that strong correlation between magnetic parameters and heavy metals is observed in Jelekong but is absent in Sarimukti suggests that the use of magnetic measurement as a proxy measurement for heavy metal content in leachate is plausible provided that the magnetic susceptibility exceeds certain threshold value. Moreover, the accumulation of magnetic minerals and heavy metals in leachate might depend on the activity and the age of landfill site.  相似文献   

18.
垃圾填埋场抽水试验及降水方案设计   总被引：2，自引：0，他引：2  
张文杰  陈云敏 《岩土力学》2010,31(1):211-215
垃圾填埋场中的渗滤液水位过高会引发一系列环境和稳定问题,工程上可用竖井抽水降低渗滤液水位。通过在填埋场现场进行抽水试验,确定垃圾土的渗透系数和抽水影响半径,在此基础上对填埋场降水的瞬态流问题进行有限元模拟,分析了抽水井口径和间距对填埋场降水的影响,提出了降水方案的设计步骤和方法。抽水试验表明,现场垃圾的渗透系数约为3.6×10-4cm/s,抽水影响半径约为20m。数值分析表明,井径的变化对于降水效果影响不大,而合理选择抽水井间距对降水十分关键。进行抽水方案设计时,应首先根据工期和降水幅度要求计算井间距,按井的出水速度选择水泵,再根据水泵确定井径,最后根据井径和过滤层形式确定钻孔尺寸并选择钻机。  相似文献   

19.
This study draws attention to the fact that natural processes can mobilize thallium （Tl）, a highly toxic metal, which may enter the food chain with severe health impacts on the local human population. A rural area having independent Tl mineralization in southwestern Guizhou, China, was chosen for a pilot study. Tl contents of soils extracted by HNO3 in the study area range from 35-165 mg/kg in soils from the mining area, 14-78 mg/kg in alluvial deposits downstream, and 〈0.2-0.5 mg/kg in soils from the background area. Tl contents in ammonium acetate EDTA-extracted fraction are 0.013-1.3 mg/kg, less than 1% of concentration in HNO3-extracted fraction. The amounts of Tl in NH4Ac-extracted fraction were thought to be more exchangeable and bioavailable, i.e., immediately available to plants and/or available to plant roots over a period of years. Tl concentration in crops exhibits species-dependent preferences. The enrichment of Tl in edible crop species decreases in the following order： green cabbage〉chili〉Chinese cabbage〉rice〉com. The highest level of Tl in green cabbage is up to 500 mg/kg （DW）, surpassing the values of Tl in the soils （13-59 mg/kg）. The enrichment factor for TI in green cabbage is up to 1-10 when considering the HNO3-extracted Tl, but the factor highly rises to 30-1300 while considering the NH4Ac-extracted Tl. The average daily uptake of Tl by the local villagers through consumption of locally planted crops was estimated at about 1.9 mg per person, which is 50 times the daily ingestion from the Tl-free background area.  相似文献   

20.
Geo-environmental assessment and geophysical investigations were carried out over the only functional municipal solid waste disposal site of the city of Addis Ababa, Ethiopia, known locally as Koshe. The accumulated wastes from Koshe have impact on the surrounding human and physical environment since the disposal site was not designed. The study deserves emphasis because the city of Addis Ababa currently obtains a considerable portion of its domestic water supply from a well field developed not much farther from and along a groundwater flow direction in relation to the waste disposal site. It was found out that the leachates from the site contain high concentration of biological oxygen demand, chemical oxygen demand, chloride and sulphate besides high concentration of cobalt, nickel and zinc in the surrounding soils. The geophysical results have mapped weak zones and near-vertical discontinuities that could potentially be conduits for the leachate from the wastes into the deep groundwater system. Further, a zone of potential leachate migration from the landfill was identified from the electrical models; the location of this zone is consistent with the predicted direction of groundwater flow across the site. The results further suggested that the open dump site tends to cause increasing amount of pollution on the surrounding soil, surface and ground waters. Furthermore, it was observed that the Koshe waste disposal site has grown beyond its capacity and the poor management of the open dump landfill has reduced the aesthetic value of the surrounding environments. The need to change/relocate the existing waste disposal site to a more suitable and technologically appropriate site is emphasized.  相似文献   

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